JP2008250095A - Protection film for polarizing plate, polarizing plate and liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a protection film for polarizing plate which is hardly stripped due to heat and moisture change and has high durability as a constituent element of a polarizing plate, to provide a polarizing plate comprising the protection film for polarizing plate, and to provide a liquid crystal display device for keeping the quality of a display image with high quality over a long term. <P>SOLUTION: The protection film for polarizing plate is characterized in that at least a first cover layer having hydrophobicity and at least a second cover layer having hydrophilicity are laminated on the one side surface of a transparent base film, wherein at least one easy-adhesion layer presenting an I/O value between the I/O value of the first cover layer and the I/O value of the second cover layer is disposed between the first cover layer and the second cover layer. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a protective film for a polarizing plate provided with a plurality of coating layers for realizing low moisture permeability, a polarizing plate using the protective film for a polarizing plate, and a liquid crystal display device using the polarizing plate.

  Recently, liquid crystal display devices (hereinafter referred to as LCDs) are widely used in place of CRTs because of their thinness, light weight, and low power consumption. The demand for polarizing plates is rapidly increasing with the spread of LCDs. The field of use is also expanding from small products such as conventional calculators and watches to large products such as automotive instruments, PC monitors, and televisions.

In the polarizing plate, a polarizing plate protective film (hereinafter sometimes referred to as a protective film or a protective layer) is bonded to both surfaces or one surface of a polarizer having polarizing ability through an adhesive layer.
As a material of the polarizer, polyvinyl alcohol (hereinafter sometimes referred to as PVA) is mainly used, and the PVA film is uniaxially stretched and then dyed with iodine or a dichroic dye, or dyed. Then, the polarizer is formed by stretching and then crosslinking with a boron compound.
The protective film is mainly cellulose triacetate (hereinafter referred to as TAC) because it is optically transparent and has low birefringence, a smooth surface, and excellent adhesion to a polarizer made of PVA by saponification. Is sometimes used).

  Here, when cellulose triacetate is used as a protective layer, display size unevenness may occur due to changes in the size of the polarizer due to changes in temperature and humidity during long-term use, and improvements are desired.

On the other hand, since liquid crystal display devices are often in use for a long time at all times, the polarizing plate is long-term so that the image quality of the LCD does not deteriorate even in long-term use in an environment with temperature and humidity changes. Durability has been demanded. In particular, it is necessary to withstand the improvement in light emission intensity from the backlight accompanying the increase in luminance of the liquid crystal display device and the temperature rise from the backlight.
That is, with the expansion of applications of liquid crystal display devices, durability under severe conditions such as higher temperatures and higher humidity has been required.

As a protective film with reduced moisture permeability, for example, a sheet made of a norbornene-based resin as a highly hydrophobic resin is useful in order to solve the unevenness of the display image during long-term use accompanying changes in temperature and humidity. Has been reported (see Patent Document 1).
However, a sheet made of norbornene-based resin has a problem that moisture permeability is sufficiently small and it is difficult to receive a change in humidity, but adhesion to a polarizer is insufficient and productivity is low.

Moreover, it has been reported that the wet heat property of a polarizing plate improves by using the protective film which provided the layer containing a vinylidene chloride copolymer on the surface of a cellulose triacetate film (patent documents 2-3).
However, even in the techniques disclosed in Patent Documents 2 and 3, the wet heat resistance is improved, but the hydrophobicity of the vinylidene chloride copolymer is high, and the layer containing the copolymer and the other more hydrophilic layers Adhesion is insufficient.
In addition, with the materials and film thicknesses disclosed in Patent Documents 2 and 3, a sufficient moisture permeability reduction effect intended in the present invention cannot be obtained.

JP-A-10-101907 JP-A-62-161103 JP 2001-343526 A

The present invention aims to solve the above-described problems and achieve the following objects. That is, an object of the present invention is to provide a polarizing plate protective film having a low durability and a high durability as a constituent element of a polarizing plate due to a change in heat and humidity.
Another object of the present invention is to provide a highly durable polarizing plate that has low peelability due to changes in heat and humidity.
It is another object of the present invention to provide a liquid crystal display device that can maintain a high quality display image for a long period of time.

As a result of intensive studies, the inventors have made a first coating layer exhibiting hydrophobicity and a second coating exhibiting hydrophilicity on one surface of a transparent substrate film (hereinafter also referred to as a substrate layer). In the protective film for a polarizing plate in which the coating layer is laminated via the easy adhesion layer, the hydrophilicity / hydrophobicity of the easy adhesion layer is between the hydrophilicity / hydrophobicity of the first coating layer and the hydrophilicity / hydrophobicity of the second coating layer. It was found that the above-mentioned problem can be solved by the value of.
The present invention is based on the above findings by the present inventors, and means for solving the above problems are as follows. That is,
<1> On one surface of the transparent substrate film, a coating layer is formed by laminating at least one or more of the first coating layer exhibiting hydrophobicity and the second coating layer exhibiting hydrophilicity, An easy-adhesion layer showing an I / O value between the I / O value of the first coating layer and the I / O value of the second coating layer includes the first coating layer, the second coating layer, It is a protective film for polarizing plates provided with at least 1 layer between.
<2> The polarizing plate protective film according to <1>, wherein the difference between the I / O value of the first coating layer and the I / O value of the second coating layer is 0.5 or more. .
<3> From <1>, wherein the difference between the I / O value of the first coating layer, the I / O value of the second coating layer, and the I / O value of the easy-adhesion layer is 0.1 or more. <2> It is a protective film for polarizing plates in any one.
<4> The polarizing plate according to any one of <1> to <3>, wherein the easy-adhesion layer has a refractive index between the refractive index of the first coating layer and the refractive index of the second coating layer. Protective film.
<5> The protective film for a polarizing plate according to any one of <1> to <4>, wherein the easy adhesion layer includes a compound contained in each of the first coating layer and the second coating layer.
The <6> 2nd coating layer is a protective film for polarizing plates in any one of said <1> to <5> provided in the outermost layer.
<7> The protective film for a polarizing plate according to any one of <1> to <6>, wherein at least one of the second coating layers contains a hydrophilic polymer compound.
<8> The protective film for a polarizing plate according to <7>, wherein the hydrophilic polymer compound is polyvinyl alcohol.
<9> The polarizing plate protection according to any one of <1> to <8>, wherein at least one of the first coating layers has a polymer containing a repeating unit derived from a chlorine-containing vinyl monomer. It is a film.
<10> The protective film for a polarizing plate according to <9>, wherein the chlorine-containing vinyl monomer is vinylidene chloride.
<11> The transparent substrate film includes cellulose acylates, and the cellulose acylates are any one of cellulose acetate, cellulose acetate propionate, and cellulose acetate butyrate. It is a protective film for polarizing plates in any one.
<12> The polarizing plate protective film according to any one of <1> to <11>, wherein the easy-adhesion layer has a thickness of 0.05 μm or more and 5 μm or less.
<13> The protective film for a polarizing plate according to any one of <1> to <12>, wherein the coating layer has a thickness of 0.05 μm or more and 10 μm or less.
<14> The protective film for a polarizing plate according to any one of <1> to <13>, wherein the transparent base film has a thickness of 30 to 120 μm.
<15> A coating solution preparation step for an easy adhesion layer, which shows hydrophobicity and prepares a coating solution for an easy adhesion layer using a water dispersion of a component derived from a compound contained in the first coating layer as a solvent. It is a manufacturing method of the protective film for polarizing plates characterized by these.
<16> A first coating layer coating solution preparing step of preparing a first coating layer coating solution for forming a first coating layer using a solvent as a solvent, and forming a second coating layer using water as a solvent. It is a manufacturing method of the protective film for polarizing plates as described in said <15> including the coating liquid preparation process of the 2nd coating layer which prepares the coating liquid for 2nd coating layers.
<17> A polarizing plate comprising the polarizing plate protective film according to any one of <1> to <14>, and a polarizer.
<18> A liquid crystal display device comprising the polarizing plate according to <17> and a liquid crystal cell.

According to the present invention, it is possible to provide a polarizing plate protective film that has low durability and high durability as a component of the polarizing plate due to changes in heat and humidity.
Moreover, according to the present invention, it is possible to provide a polarizing plate having high durability and low peelability due to changes in heat and humidity.
In addition, according to the present invention, it is possible to provide a liquid crystal display device that can maintain a high quality display image for a long period of time.

Below, the protective film for polarizing plates concerning this invention, a polarizing plate, and a liquid crystal display device are demonstrated in detail.
In the description of the present embodiment, a numerical range expressed using “to” means a range including numerical values described before and after “to” as a lower limit value and an upper limit value.
In the description of the present embodiment, “45 °”, “parallel” or “orthogonal” means that the angle is within a range of strictly less than ± 5 °. The error from the exact angle is preferably less than 4 °, more preferably less than 3 °. Regarding the angle, “+” means the clockwise direction, and “−” means the counterclockwise direction. Further, the “slow axis” means a direction in which the refractive index is maximized. The “visible light region” means 380 to 780 nm. Further, the refractive index measurement wavelength is a value in the visible light region (λ = 550 nm) unless otherwise specified.

In the description of the present embodiment, the term “polarizing plate” is used to include both a long polarizing plate and a polarizing plate cut into a size incorporated in a liquid crystal device unless otherwise specified. Yes. The “cutting” here includes “punching” and “cutting out”.
In the description of the present embodiment, “polarizing film” and “polarizing plate” are distinguished from each other. However, “polarizing plate” is a laminate having a transparent protective film that protects the polarizing film on at least one side of “polarizing film”. It shall mean the body.

(Protective film for polarizing plate)
FIG. 1 is a cross-sectional view showing a configuration of a protective film for polarizing plate in the present embodiment. As shown in FIG. 1, the protective film 1 for polarizing plates of this embodiment is provided on one surface of the transparent base film 11 and the transparent base film 11 and exhibits a hydrophobic property. And at least one coating layer 12 (hereinafter sometimes referred to as a low moisture permeable layer 12) in which at least one second coating layer 12b exhibiting hydrophilicity is laminated.
In addition, the hard coat layer 40 which has hard-coat property may be provided in the other surface (surface on the opposite side to the side in which the coating layer 12 was provided in the transparent base film 11) of the transparent base film 11. preferable.
It is also preferable that the second coating layer also serves as a hard coat layer having hard coat properties. In this case, it is preferable to perform a saponification treatment described later on the other surface of the transparent substrate film.
Further, it is more preferable that the hard coat layer 40 has an internal scattering property or a surface scattering property. Specifically, by including particles or the like in the hard coat layer 40, internal scattering properties and surface scattering properties can be expressed.
The hard coat layer 40 is preferably composed of two or more layers having different refractive indexes for the purpose of reducing the reflectance of the surface. In such a case, the surface-side layer (the side farther from the polarizer 50) It is preferable that the refractive index of the inner layer is lower than the refractive index of the inner layer (the layer closer to the polarizer 50 than the surface-side layer).
Furthermore, it is preferable from an adhesive viewpoint between layers to have an easily bonding layer between the transparent base film 11 and the coating layer 12, and at least in the surface of the coating layer 12a.
The easy-adhesion layer is preferably composed of a plurality of layers, and any one of the layers may be an antistatic layer.

<< Coating layer >>
The first protective film is formed by laminating at least one or more layers each of a first coating layer exhibiting hydrophobicity and a second coating layer exhibiting hydrophilicity on one surface of the transparent substrate film, An easy adhesion layer is provided between the first coating layer and the second coating layer.
Further, the inorganic value / organic value (hereinafter sometimes referred to as I / O value) of the easy-adhesion layer is the I / O value of the first coating layer and the I / O value of the second coating layer. The value between.
Hereinafter, unless otherwise specified, the term “coating layer” refers to “the entire coating layer” in which at least one or more “first coating layer” and “second coating layer” are laminated. And

[I / O value]
The I / O value is a value that treats the polarity of various organic compounds in an organic concept, and is one of the functional group contribution methods for setting parameters for each functional group.
The I / O values are shown in an organic conceptual diagram (Yoshio Koda, Sankyo Publishing (1984)); No., 719-725 (1957); Fragrance Journal, 34, 97-111 (1979); Fragrance Journal, 50, 79-82 (1981); Explained.
The concept of the I / O value is that the properties of a compound are divided into an organic group exhibiting a covalent bond and an inorganic group exhibiting an ionic bond, and all organic compounds are named as an organic axis and an inorganic axis. Each point on the coordinates is shown.
The inorganic value is obtained by quantifying the magnitude of the influence on the boiling point of various substituents and bonds of an organic compound, based on the hydroxyl group.
Specifically, when the distance between the boiling point curve of a linear alcohol and the boiling point curve of a linear paraffin is about 100 ° C., the influence of one hydroxyl group is set to 100 as a numerical value. Based on this numerical value, the value obtained by quantifying the influence on the boiling point of various substituents or various bonds is the inorganic value of the substituent that the organic compound has. For example, the inorganic value of the —COOH group is 150, and the inorganic value of the double bond is 2.
Therefore, the inorganic value of a certain kind of organic compound means the sum of inorganic values such as various substituents and bonds of the compound.
The organic value is determined based on the influence of the methylene group in the molecule as a unit and the boiling point of the carbon atom representing the methylene group. That is, since the average value of the boiling point increase due to addition of one carbon in the vicinity of 5 to 10 carbon atoms of the linear saturated hydrocarbon compound is 20 ° C., the organic value of one carbon atom is set to 20 on the basis of this. Based on this, the value obtained by quantifying the influence on the boiling point of various substituents and bonds is the organic value. For example, the organic value of a nitro group (—NO ₂ ) is 70.
The closer the I / O value is to 0, the more non-polar (hydrophobic and organic) organic compounds are, and the larger the I / O value is, the more polar (hydrophilic and inorganic) organic compounds are. Show.

-I / O value calculation method-
An example of a method for calculating the I / O value will be described below.
For example, when calculating the I / O value of a vinylidene chloride / acrylonitrile copolymer (copolymer composition (molar ratio): 9/1), the inorganic value and organic value of the copolymer are as follows: And calculated by the following formula: (inorganic value of the copolymer) / (organic value of the copolymer).

  The inorganic value of the copolymer is calculated by calculating the sum of the inorganic value of the vinylidene chloride × molar ratio of the vinylidene chloride and the inorganic value of the acrylonitrile × the molar ratio of the acrylonitrile.

Since the vinylidene chloride has two chloro groups and the acrylonitrile has one cyano group,
The inorganic value of the vinylidene chloride is calculated as 10 (inorganic value of chloro group) × 2 (number of chloro groups) = 20.
The inorganic value of the acrylonitrile is calculated as 70 (inorganic value of cyano group) × 1 (number of cyano groups) = 70.
That is, the inorganic value of the copolymer is calculated to be 250 by calculating the following formula: 20 × 9 (molar ratio of vinylidene chloride) + 70 × 1 (molar ratio of acrylonitrile).

  On the other hand, the organic value of the copolymer is calculated by calculating the sum of the organic value of the vinylidene chloride × the molar ratio of the vinylidene chloride and the organic value of the acrylonitrile × the molar ratio of the acrylonitrile. .

Since the vinylidene chloride has 2 chloro groups and 2 carbon atoms, and the acrylonitrile has 1 cyano group and 3 carbon atoms, the organic value of the vinylidene chloride is 40 (chloro group). Of organic value) × 2 (number of chloro groups) +20 (organic value of carbon atoms) × 2 (number of carbon atoms) = 120.
The organic value of the acrylonitrile is calculated as 20 (organic value of cyano group) × 1 (number of cyano groups) +20 (organic value of carbon atom) × 3 (number of carbon atoms) = 80.
That is, the organic value of the copolymer is 1,160 by calculating the following formula: 120 × 9 (molar ratio of the vinylidene chloride) + 80 × 1 (molar ratio of the acrylonitrile). Calculated.
Therefore, it is calculated that the I / O value of the copolymer is 250 (inorganic value of the copolymer) / 1,160 (organic value of the copolymer) = 0.216.

  The I / O values of the first coating layer, the easy-adhesion layer, the second coating layer, and the hard coat layer are calculated for the material used as the binder (the main component constituting each layer) of each layer. In the case of being composed of a plurality of binders, the composition ratio is taken into consideration.

[Thickness of coating layer]
The thickness of the coating layer is preferably 1.1 to 10 μm, more preferably 1.2 to 7 μm, and still more preferably 1.5 to 5 μm. If the thickness of the coating layer is equal to or less than the upper limit value, it is preferable because it has excellent low moisture permeability and does not cause adverse effects such as an increase in curling and deterioration of the brittleness of the coating layer. If the curl becomes too large, it will hinder subsequent processes for producing a polarizing plate, for example, a bonding process with a polarizing film and handling. Further, it is not preferable that the curl remains not only in the manufacturing process but also as the polarizing plate, which causes display unevenness in the LCD.
Therefore, in order to reduce the curl to such an extent that it does not occur or is practically not problematic, it is preferable to set the upper limit of the coating layer thickness within the above range.
Moreover, it is preferable if the thickness of the coating layer is equal to or less than the above upper limit value because there are no adverse effects such as formation of a brittle film or easy coloring. On the other hand, the lower limit of the thickness of the coating layer is defined as a range that is more preferable than moisture resistance, and the effect of the present invention can be sufficiently exhibited by setting the above range.

Regarding the thickness of the coating layer, in-plane uniformity is also required. The coating layer of the present invention is produced continuously by wet coating on a roll-shaped transparent substrate film having a width of 1 m or more and less than 3 m and a total length of 100 m or more and less than 10,000 m. However, the thickness distribution is preferably within ± 20% of the average thickness and within ± 10% of the average thickness in the width and longitudinal planes. More preferably, the variation is within ± 5% of the average thickness.
If the variation is within ± 20% with respect to the average thickness, the variation in the moisture permeability of the coating layer by the measurement method described later can be suppressed, and the display quality unevenness that is the effect of the present invention is further reduced.

[Haze of coating layer]
The haze of the coating layer is preferably 5% or less, more preferably 3% or less, and still more preferably 1% or less. The ratio between the surface haze and the internal haze may be arbitrary, but the surface haze is particularly preferably 1% or less.

[Moisture permeability]
Next, the moisture permeability will be described in detail.
The measurement method of moisture permeability is "Polymer Physical Properties II" (Polymer Experiment Course 4, Kyoritsu Shuppan), pages 285-294: Measurement of vapor permeation (mass method, thermometer method, vapor pressure method, adsorption amount method) Can be applied as appropriate.

70 mmφ film sample according to the present invention was conditioned at 60 ° C. and 95% RH for 24 hours, respectively, and from the mass difference before and after humidity adjustment, using a moisture permeable cup according to JIS Z-0208, moisture permeability = after moisture conditioning The amount of water per unit area (g / m ² ) was calculated by mass-mass before humidity control.
At this time, the operation of taking out and weighing the cup placed in the thermo-hygrostat at an appropriate time interval is repeated, and the increase in mass per unit time is obtained with two successive weighings, and it becomes constant within 5%. The evaluation continued until. Moreover, in order to exclude the influence by the moisture absorption etc. of a sample, the blank cup which does not put a hygroscopic agent was measured, and the value of moisture permeability was correct | amended.
The moisture permeability of a commercially available cellulose acetate film measured by the above measurement method is generally 80 μm in thickness and 1,100 to 1,300 g / m ² · day under the above conditions.
On the other hand, the upper limit of the moisture permeability of the polarizing plate protective film of the present invention is preferably 700 g / m ² · day or less, more preferably 500 g / m ² · day or less, and 300 g / m ² · day or less. It is particularly preferred that If the moisture permeability is higher than the above upper limit value, unevenness of the display image is likely to occur due to a change in the size of the polarizing film due to changes in temperature and humidity during long-term use, and the reduction effect is low. The lower limit is not particularly limited, but is preferably larger than 0 g / m ² · day, preferably 20 g / m ² · day or more, more preferably 30 g / m ² · day or more from the viewpoint of productivity during polarizing plate processing. preferable.
Therefore, the moisture permeability of the polarizing plate protective film of the present invention is particularly preferably in the range of 30 to 300 g / m ² · day. Within this range, the performance (polarization degree, single plate transmittance) as a polarizing plate does not deteriorate, and unevenness in the display image due to changes in the size of the polarizing film due to changes in temperature and humidity during long-term use. Occurrence can be suppressed.

  In addition, a measurement method called a mocon method is also preferably used for measuring moisture permeability. In the present invention, the moisture permeability measured by the Mocon method was measured and calculated with a PERMARTRAN-W3 / 33 type water vapor permeability measuring device manufactured by Mocon under the conditions of 40 ° C. and a relative humidity of 90% RH.

[Light resistance]
JIS K 5600-7-5 “Paint General Test Method—Light Resistance—” describes that a light resistance test is performed using a xenon lamp as a light source.
In the present invention, a xenon lamp light source is used as the light resistance test, the irradiance is 100 ± 25 W / m ² (wavelength: 310 to 400 nm), the test chamber temperature is 35 ± 5 ° C., the black panel temperature is 50 ± 5 ° C., the relative humidity. JIS K 5600-7-5 is adopted under the condition of 65 ± 15%.
In the present invention, the degree of change in appearance (color of transmitted light) was evaluated as a measure for measuring the light resistance of the polarizing plate protective film.

The inventors of the present invention quantitatively measure and display these values as a numerical value to be displayed by the following formula (A), and a transmitted light color change amount (color difference ΔE * ab value in CIE 1976 L * a * b * color space) ) Was found to be appropriate.
For example, if the transparency deteriorates (the transmittance decreases), ΔL * increases, and as a result, the transmitted light color change amount ΔE * ab value increases.
Further, if the color of the transmitted light changes, Δa * and Δb * increase, and the transmitted light color change ΔE * ab value also increases. The correspondence between the transmitted light color change ΔE * ab value and the sensory evaluation results for the appearance change is almost as shown in Table 1 below, and the color change amount indicates the degree of appearance change of the polarizing plate protective film, that is, the light resistance. It can be seen that this is an appropriate evaluation characteristic that reflects correctly.
The transmitted light color change ΔE * ab value is preferably 4.5 or less, more preferably 3.0 or less, and even more preferably 2.0 or less. By setting the transmitted light color change ΔE * ab value to 4.5 or less, high light resistance can be achieved.

ΔE * ab = [(ΔL *) ² + (Δa *) ² + (Δb *) ² ] ^1/2 Equation (A)
ΔL * = L1 * -L2 *
Δa * = a1 * −a2 *
Δb * = b1 * −b2 *
(In the formula (A), L1 *, a1 *, b1 *, L2 *, a2 *, and b2 * indicate the color of the transmitted light of the CIE standard light source C of the polarizing plate protective film as CIE1976L * a * b *. The color space is expressed by L * value, a * value, and b * value, and L1 *, a1 *, and b1 * are L of the polarizing plate protective film before the light resistance test is performed. * Value, a * value, and b * value are represented. L2 *, a2 *, and b2 * are L * value, a * value, and b * of the polarizing plate protective film after the light resistance test is performed. Represents the value.)

  In the above formula (A), L1 *, a1 *, b1 *, L2 *, a2 *, and b2 * are values calculated in detail by the following method.

[Calculation of L1 *, a1 *, and b1 *]
Using a spectrophotometer (UV-3150, manufactured by Shimadzu Corporation), the spectral transmittance is measured in a wavelength region of 380 to 780 nm.
Next, the obtained spectral transmittance data and the spectral distribution data of the CIE C standard light source are multiplied for each wavelength to obtain spectral transmitted light for the C light source.
The LIE *, a *, and b * values of the CIE 1976 L * a * b * color space in the CIE standard light source C are calculated from the obtained spectral transmission light data under the standard light, and L1 *, a1 *, and Let b1 *.

[Calculation of L2 *, a2 *, and b2 *]
Using a light resistance test apparatus (super xenon weather meter SX120 type (long life xenon lamp), Suga Test Instruments Co., Ltd.) and carrying out a light resistance test 120 hr according to JIS K 5600-7-5, L * value, a * value, and b * value calculated from values measured in the same manner using a photometer (UV-3150, manufactured by Shimadzu Corporation) are set as L2 *, a2 *, and b2 *. .

  In the protective film for polarizing plate in the present invention, the curl value represented by the following formula (1) is preferably in the range of −15 to +15, more preferably in the range of −12 to +12, and −10 ~ + 10 is more preferred. In this case, the measurement direction of the curl in the sample is measured in the conveyance direction of the base material in the case of application in a web form. In the following formula (1), R represents a radius of curvature (m).

  Curl value = 1 / R ... Formula (1)

It is preferable that the curl value is in the above range and the curl is small. If it is in said range, a crack and film | membrane peeling will not occur by manufacture of a film which has a coating layer, a process, and handling in a market, and it is preferable. It is possible to reduce the curl within the above range and increase the surface hardness by setting the volume shrinkage ratio before and after curing to 15% or less.
The curl is measured using the curl measurement template of Method A in “Measuring Method of Curling of Photographic Film” of JIS K-7619-1988. The measurement conditions are 25 ° C., humidity 60% RH, and humidity control time 10 hours.
Here, “curl plus” means a curl in which the coating layer coating side of the film is inside the curve, and “minus” means a curl in which the coating side is outside the curve.

  In the protective film for polarizing plate of the present invention, when only the humidity is changed to 80% RH to 10% RH based on the curl measurement method, the absolute value of the difference between the curl values is in the range of 24 to 0. Preferably, it is in the range of 15-0, more preferably in the range of 8-0. This is a property related to handling properties, peeling, and cracking when a polarizing plate protective film is attached under various humidity conditions.

The cracking resistance of the protective film for polarizing plate of the present invention is preferably 30 mm or less, more preferably 25 mm or less, with a radius of curvature at which cracking occurs when the coating layer coating side is rolled outward. More preferably, it is 20 mm or less.
About the crack of an edge part, it is preferable that there is no crack or the length of a crack is less than 1 mm on average. This crack resistance is an important characteristic for preventing crack defects in handling such as coating, processing, cutting, and sticking of a film having a coating layer.

[First coating layer]
Examples of the first coating layer include polymers containing repeating units derived from chlorine-containing vinyl monomers (hereinafter also referred to as chlorine-containing polymers). As chlorine-containing vinyl monomers, , Vinyl chloride and vinylidene chloride. The chlorine-containing polymer can be obtained by copolymerizing these vinyl chloride or vinylidene chloride monomers with a monomer copolymerizable therewith.

-I / O value of the first coating layer-
There is no restriction | limiting in particular as I / O value of a 1st coating layer, According to the objective, it selects suitably, For example, 0.1-1.2 are preferable and 0.5-1.0 are more preferable. When the I / O value exceeds 1.2, there is a possibility that the hydrophobicity becomes low and the moisture permeability becomes high.
Further, it is particularly preferable that the difference between the I / O value of the first coating layer and the I / O value of the second coating layer described later is 0.5 or more.
As a method of adjusting the I / O value of the first coating layer, there is a method of appropriately selecting at least one of the type of monomer constituting the copolymer and the polymerization ratio (content) when the monomer is polymerized. By doing so, for example, the I / O value of the first coating layer can be adjusted in the range of 0.1 to 1.2.

-Monomers copolymerizable with chlorine-containing vinyl monomers-
Examples of the copolymerizable monomer include olefins, styrenes, acrylic acid esters, methacrylic acid esters, acrylamides, methacrylamides, itaconic acid diesters, maleic acid esters, fumaric acid diesters, N- Examples thereof include monomers selected from alkylmaleimides, maleic anhydride, acrylonitrile, vinyl ethers, vinyl esters, vinyl ketones, vinyl heterocyclic compounds, glycidyl esters, unsaturated nitriles, unsaturated carboxylic acids and the like.

Examples of olefins include dicyclopentadiene, ethylene, propylene, 1-butene, 1-pentene, isoprene, chloroprene, butadiene, 2,3-dimethylbutadiene and the like.
Examples of styrenes include styrene, methyl styrene, dimethyl styrene, trimethyl styrene, ethyl styrene, isopropyl styrene, chloromethyl styrene, methoxy styrene, acetoxy styrene, chloro styrene, dichloro styrene, bromo styrene, trifluoromethyl styrene, vinyl. And benzoic acid methyl ester.

Specific examples of acrylic esters and methacrylic esters include the following.
Methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, amyl acrylate, 2-ethylhexyl acrylate, octyl acrylate, t-octyl acrylate, 2-methoxyethyl acrylate, 2-butoxyethyl acrylate, 2-phenoxyethyl acrylate, chloroethyl acrylate, Cyanoethyl acrylate, dimethylaminoethyl acrylate, benzyl acrylate, methoxybenzyl acrylate, furfuryl acrylate, phenyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, butyl methacrylate, amyl methacrylate, hexyl methacrylate, 2-ethylhexyl methacrylate, oct Methacrylate, benzyl methacrylate, cyanoacetoxyethyl methacrylate, chlorobenzyl methacrylate, sulfopropyl methacrylate, N-ethyl-N-phenylaminoethyl methacrylate, 2-methoxyethyl methacrylate, 2- (3-phenylpropyloxy) ethyl methacrylate, dimethylamino Phenoxyethyl methacrylate, furfuryl methacrylate, tetrahydrofurfuryl methacrylate, phenyl methacrylate, cresyl methacrylate, naphthyl methacrylate, hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, 3-chloro-2-hydroxypropyl methacrylate, 3 -Chloro-2-hydro Cypropyl methacrylate, 2,2-dimethylhydroxypropyl acrylate, 5-hydroxypentyl acrylate, diethylene glycol monoacrylate, trimethylolpropane monoacrylate, pentaerythritol monoacrylate, 2,2-dimethyl-3-hydroxypropyl methacrylate, 5-hydroxypropyl Methacrylate, diethylene glycol monomethacrylate, trimethylolpropane monomethacrylate, pentaerythritol monomethacrylate.

Specific examples of vinyl ethers include the following.
Methyl vinyl ether, butyl vinyl ether, hexyl vinyl ether, octyl vinyl ether, decyl vinyl ether, ethyl hexyl vinyl ether, methoxyethyl vinyl ether, ethoxyethyl vinyl ether, chloroethyl vinyl ether, 1-methyl-2,2-dimethylpropyl vinyl ether, 2-ethylbutyl ether, dimethylaminoethyl Vinyl ether, diethylaminoethyl vinyl ether, butylaminoethyl vinyl ether, benzyl vinyl ether, tetrahydrofurfuryl vinyl ether, vinyl phenyl ether, vinyl tolyl ether, vinyl chlorophenyl ether, vinyl-2,4-dichlorophenyl ether, vinyl naphthyl ether, vinyl anthranyl ether .

Specific examples of the vinyl esters include the following.
Vinyl acetate, vinyl propionate, vinyl butyrate, vinyl isobutyrate, vinyl dimethyl propionate, vinyl ethyl butyrate, vinyl valerate, vinyl caproate, vinyl chloroacetate, vinyl dichloroacetate, vinyl methoxyacetate, Vinyl butoxy acetoacetate, vinyl phenyl acetate, vinyl acetoacetate, vinyl lactate, vinyl-β-phenylbutyrate, vinyl cyclohexyl carboxylate, vinyl benzoate, vinyl salicylate, vinyl chlorobenzoate, vinyl tetrachlorobenzoate, vinyl naphthoate.

  Acrylamides include acrylamide, methylacrylamide, ethylacrylamide, propylacrylamide, butylacrylamide, t-butylacrylamide, cyclohexylacrylamide, benzylacrylamide, hydroxymethylacrylamide, methoxyethylacrylamide, dimethylaminoethylacrylamide, phenylacrylamide, dimethylacrylamide, and diethyl. Examples include acrylamide, β-cyanoethyl acrylamide, and N- (2-acetoacetoxyethyl) acrylamide.

  Examples of methacrylamides include methacrylamide, methyl methacrylamide, ethyl methacrylamide, propyl methacrylamide, butyl methacrylamide, tert-butyl methacrylamide, cyclohexyl methacrylamide, benzyl methacrylamide, hydroxymethyl methacrylamide, methoxyethyl methacrylamide , Dimethylaminoethylmethacrylamide, phenylmethacrylamide, dimethylmethacrylamide, diethylmethacrylamide, β-cyanoethylmethacrylamide, N- (2-acetoacetoxyethyl) methacrylamide and the like.

  Further, acrylamides having a hydroxyl group can also be used, and examples thereof include N-hydroxymethyl-N- (1,1-dimethyl-3-oxo-butyl) acrylamide, N-methylolacrylamide, and N-methylol. Examples include methacrylamide, N-ethyl-N-methylol acrylamide, N, N-dimethylol acrylamide, N-ethanol acrylamide, N-propanol acrylamide, N-methylol acrylamide, and the like.

  Examples of the itaconic acid diesters include dimethyl itaconate, diethyl itaconate, and dibutyl itaconate. Examples of maleic acid diesters include diethyl maleate, dimethyl maleate, and dibutyl maleate. Examples of the fumaric acid diesters include diethyl fumarate, dimethyl fumarate, dibutyl fumarate and the like.

Examples of vinyl ketones include methyl vinyl ketone, phenyl vinyl ketone, methoxyethyl vinyl ketone, and the like. Examples of the vinyl heterocyclic compound include vinyl pyridine, N-vinyl imidazole, N-vinyl oxazolidone, N-vinyl triazole, and N-vinyl pyrrolidone. Examples of glycidyl esters include glycidyl acrylate and glycidyl methacrylate. Examples of unsaturated nitriles include acrylonitrile and methacrylonitrile. Examples of N-alkylmaleimides include N-ethylmaleimide and N-butylmaleimide.

Examples of the unsaturated carboxylic acids include acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid and the like, and further anhydrides such as fumaric acid, itaconic acid and maleic acid.
Two or more kinds of these copolymerizable monomers may be used.

  Examples of the chlorine-containing polymer in the present invention include JP-A-53-58553, JP-A-55-43185, JP-A-57-139109, JP-A-57-139136, JP-A-60. -235818, JP-A 61-108650, JP-A 62-256871, JP-A 62-280207, JP-A 63-256665, and the like.

  The proportion of the chlorine-containing vinyl monomer in the chlorine-containing polymer is preferably from 50 to 99 mass%, more preferably from 60 to 98 mass%, still more preferably from 70 to 97 mass%. If the ratio of the chlorine-containing vinyl monomer is 50% or more, problems such as deterioration of moisture permeability will not occur, and if it is 99% or less, solubility in various solvents is obtained, which is preferable. .

Chlorine-containing polymers are available from Asahi Kasei Chemicals Corporation and Kureha Chemical Corporation. The following are listed as available from Asahi Kasei Chemicals Corporation.
“Saran Resin R241C”, “Saran Resin F216”, “Saran Resin R204”, “Saran Latex L502”, “Saran Latex L529B”, “Saran Latex L536B”, “Saran Latex L544D”, “Saran Latex L549B”, “Saran Latex L551B” “Saran Latex L557”, “Saran Latex L561A”, “Saran Latex L116A”, “Saran Latex L411A”, “Saran Latex L120”, “Saran Latex L123D”, “Saran Latex L106C”, “Saran Latex L131A”, “ “Saran Latex L111”, “Saran Latex L232A”, “Saran Latex L321B”. Among these, Saran Resin F216 is more preferably used because it is soluble in ketone solvents (such as methyl ethyl ketone and cyclohexanone).
Further, Saran Resin R204 is more preferably used because it has high crystallinity and can reduce the moisture permeability of the coating layer.

Since the first coating layer is often wet-coated, the solvent used in the coating composition is an important factor.
The requirements for the solvent include that the solute is sufficiently dissolved, and that coating unevenness and drying unevenness are less likely to occur during the drying process from coating.
Further, as another requirement of the solvent, the solvent of the coating solution for forming the first coating layer forms a mixed region between the support and the coating layer. It is necessary to select a solvent having a property of dissolving or swelling.
This is because if such a solvent is used in the coating layer coating solution, the interface between the base film and the coating layer becomes unclear because the coating layer is formed while dissolving or swelling the support immediately after coating. A layer in a region where the resin component of the coating layer and the resin component of the base film are mixed is formed.

Further, in order to achieve both control of the unevenness on the surface of the coating layer (reducing or flattening the unevenness) and the strength of the coating layer, at least a solvent that does not dissolve the transparent base film (for example, triacetylcellulose film) is used. It is preferable to mix one or more types, and it is more preferable that at least one of the solvents that dissolve the transparent substrate film has a higher boiling point than at least one of the solvents that do not dissolve the transparent substrate film.
Furthermore, it is preferable that the boiling point temperature difference between the solvent having the highest boiling point among the solvents that dissolve the transparent substrate film and the solvent having the highest boiling point among the solvents that do not dissolve the transparent substrate film is 25 ° C. or more, The temperature is more preferably 35 ° C. or higher, and further preferably 50 ° C. or higher.

When the base film is a cellulose acylate film, as a solvent having the property of dissolving or swelling the base film,
Ethers having 3 to 12 carbon atoms: Specifically, dibutyl ether, dimethoxymethane, dimethoxyethane, diethoxyethane, propylene oxide, 1,4-dioxane, 1,3-dioxolane, 1,3,5- Trioxane, tetrahydrofuran, anisole, phenetole, etc.
Ketones having 3 to 12 carbon atoms: specifically, acetone, methyl ethyl ketone, diethyl ketone, dipropyl ketone, diisobutyl ketone, cyclopentanone, cyclohexanone, methylcyclohexanone, methylcyclohexanone, etc.
Esters having 3 to 12 carbon atoms: Specifically, ethyl formate, propyl formate, n-pentyl formate, methyl acetate, ethyl acetate, methyl propionate, propion brewed ethyl, n-pentyl acetate, γ-butyrolactone, etc. ,
Organic solvent having two or more kinds of functional groups: Specifically, methyl 2-methoxyacetate, methyl 2-ethoxyacetate, ethyl 2-ethoxyacetate, ethyl 2-ethoxypropionate, 2-methoxyethanol, 2-propoxyethanol 2-butoxyethanol, 1,2-diacetoxyacetone, acetylacetone, diacetone alcohol, methyl acetoacetate, and ethyl acetoacetate.
These can be used alone or in combination of two or more. As a solvent for dissolving the transparent substrate film, a ketone solvent is preferable, and methyl ethyl ketone and cyclohexanone are particularly preferable.

As a solvent that does not dissolve the transparent substrate film (preferably triacetyl cellulose), methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, tert-butanol, 1-pentanol, 2-methyl- Examples include 2-butanol, cyclohexanol, isobutyl acetate, methyl isobutyl ketone, 2-octanone, 2-pentanone, 2-hexanone, 2-heptanone, 3-pentanone, 3-heptanone, 4-heptanone, and toluene.
These can be used alone or in combination of two or more.

  The mass ratio (A / B) of the total amount (A) of the solvent that dissolves the transparent base film and the total amount (B) of the solvent that does not dissolve the transparent base film is preferably 20/80 to 100/0, and 30/70. ~ 100/0 is more preferable, and 40/60 to 100/0 is still more preferable.

In the present invention, when the chlorine-containing polymer is vinylidene chloride, it is preferable to use tetrahydrofuran as the main solvent.
Further, by selecting a copolymer of vinylidene chloride, it is possible to dissolve in toluene, a ketone solvent, etc., and it is more preferable to use toluene, a ketone solvent, etc. without using tetrahydrofuran, and in particular, methyl ethyl ketone, cyclohexanone is used. It is particularly preferred.
Further, it is also preferable to add the above solvent within a range where the solute dissolves in tetrahydrofuran. When tetrahydrafuran is used, a reducing substance such as p-cresol, resorcin, hydroquinone, ferrous salt, hindered phenol (for example, 2,6-di-tert-butyl-4-methylphenol) is used from the viewpoint of light stabilization. It is preferable to add 0.01 to 1% by mass in the coating solution. The coating layer is preferably used because it is effective in preventing coloring of the coating layer.
When the chlorine-containing polymer is supplied as a latex dispersion, water is preferably used as the main solvent. In the case of a latex dispersion, it is preferable to use a surfactant, a thickener or the like in combination.

When the first coating layer containing a chlorine-containing polymer is applied on the transparent substrate film, in order to improve the blocking resistance, Sirisia (made by Fuji Silysia), Mizuka Seal (made by Mizusawa Chemical Co., Ltd.), 2 Silica powder such as Puseal (manufactured by Nippon Silica Industry Co., Ltd.) is added to the chlorine-containing polymer in an amount of 0.2 to 1.0 parts by mass, paraffin wax (manufactured by Nippon Seiwa Co., Ltd.), behenic acid It is also preferable to add 0.2 to 5.0 parts by mass of a wax emulsion such as (manufactured by NOF Corporation) or stearic acid (manufactured by NOF Corporation).
Further, modified waxes are preferably used as described in paragraphs [0012] to [0016] of JP-A-9-143419.

When using particles for improving blocking resistance, organic resin particles can also be used. From the viewpoint of sedimentation in the coating solution, the specific gravity is lighter than that of the silica powder, so that it is preferably used. As the organic resin particles, plastic beads are suitable, and those having particularly high transparency and a refractive index difference from the chlorine-containing polymer of 0.01 or more and 0.3 or less are preferable.
As organic resin particles, polymethyl methacrylate particles (refractive index 1.49), crosslinked poly (acryl-styrene) copolymer particles (refractive index 1.54), melamine resin particles (refractive index 1.57), polycarbonate particles (Refractive index 1.57), polystyrene particles (refractive index 1.60), crosslinked polystyrene particles (refractive index 1.61), polyvinyl chloride particles (refractive index 1.60), benzoguanamine-melamine formaldehyde particles (refractive index 1) .68) etc. are used.
Among the organic resin particles, cross-linked polystyrene particles, cross-linked polymethyl methacrylate particles, and cross-linked poly (acryl-styrene) particles are preferably used.

  Here, the refractive index of the chlorine-containing polymer can be quantitatively evaluated by directly measuring it with an Abbe refractometer or by measuring a spectral reflection spectrum or a spectral ellipsometry. The refractive index of the organic resin particles is determined by measuring the turbidity by dispersing an equal amount of the organic resin particles in a solvent in which the refractive index is changed by changing the mixing ratio of two types of solvents having different refractive indexes. Is measured by measuring the refractive index of the solvent with an Abbe refractometer.

The average particle diameter of the organic resin particles is preferably 0.5 to 12 μm, more preferably 1.0 to 8.0 μm, and still more preferably 1.5 to 6 μm. When the average particle size is 0.5 μm or more and 12 μm or less, the blocking resistance is good and preferable.
Moreover, you may use together and use 2 or more types of organic resin particles from which a particle diameter differs.

  The organic resin particles are preferably blended so as to be contained in the chlorine-containing polymer in an amount of 0.2 to 5% by mass, and blended so as to be contained in the chlorine-containing polymer in an amount of 0.25 to 1% by mass. More preferably. When the blending amount is 0.2% by mass or more and 5% by mass or less, the blocking resistance is good and the moisture permeability can be suppressed low, which is preferable.

The density of the organic resin particles is preferably ^{10~1,000mg / m 2, 100~700mg / m} 2 is more preferable.

Examples of the method for producing the organic resin particles according to the present invention include a suspension polymerization method, an emulsion polymerization method, a soap-free emulsion polymerization method, a dispersion polymerization method, a seed polymerization method and the like, and may be produced by any method. .
These production methods are described, for example, in “Experimental Methods for Polymer Synthesis” (Takayuki Otsu and Masaaki Kinoshita, Chemical Dojinsha), pages 130 and 146 to 147, “Synthetic Polymers”, Vol. 1, p. 246-290, 3rd volume, p. 1 to 108, etc., and Japanese Patent Nos. 2543503, 3508304, 2746275, 3521560, 3580320, and Japanese Patent Laid-Open No. 10-1561. Reference can be made to methods described in JP-A No. 7-2908, JP-A No. 5-297506, JP-A No. 2002-145919, and the like.

The particle size distribution of the organic resin particles is preferably monodisperse particles in view of ensuring transparency and uniformity of the coated surface. For example, when a particle having a particle size of 20% or more than the average particle size is defined as a coarse particle, the ratio of the coarse particle is preferably 1% or less of the total number of particles, and preferably 0.1% or less. More preferred is 0.01% or less.
The particle size distribution of the organic resin particles is measured by a Coulter counter method, and the measured distribution is converted into a particle number distribution. Particles having a particle size distribution as described above are also effective means of classification after the preparation or synthesis reaction. By increasing the number of classifications or increasing the degree thereof, particles having a preferable distribution can be obtained. it can.
It is preferable to use a method such as an air classification method, a centrifugal classification method, a sedimentation classification method, a filtration classification method, or an electrostatic classification method for classification.

[Fine particles]
In the present invention, fine particles may be added to the first coating layer forming coating solution. By adding fine particles, effects such as improved hardness, improved adhesion to a transparent substrate film, and reduced moisture permeability can be obtained.

  As the fine particles, any of inorganic fine particles, organic fine particles, and organic-inorganic composite fine particles can be used. Examples of the inorganic fine particles include silicon dioxide particles, titanium dioxide particles, zirconium oxide particles, aluminum oxide particles, antimony oxide particles, and indium oxide particles.

  In general, the inorganic fine particles may easily form aggregates or cracks in the coating layer after curing, simply by mixing. In the present invention, in order to increase the affinity between the inorganic fine particles and the organic component, the surface of the inorganic fine particles can be treated with a surface modifier containing an organic segment.

  2-40 volume% is preferable with respect to the volume of the 1st coating layer after filling, as for the filling amount of microparticles | fine-particles, 3-30 volume% is more preferable, and 5-30 volume% is still more preferable.

  An inorganic layered compound can also be added to the first coating layer forming coating solution. As the layer compound, synthetic mica and synthetic smectite are preferably used. Specific examples of the synthetic mica include “Micro Mica MK-100”, “Micro Mica MK-200”, “Micro Mica MK-300”, “Somasif ME-100”, “Somasif MAE”, manufactured by Corp Chemical Co., Ltd. "Somasif MTE", "Somasif MEE", "Somasif MPE", etc. are listed, and synthetic smectites include "Lucentite SWN", "Lucentite SAN", "Lucentite STN", "Lucentite SEN", "Lucentite" Tight SPN "and the like. Synthetic smectites “Lucentite STN” and “Lucentite SPN” are preferable in view of transparency of the coating layer after curing and dispersibility in the coating liquid for forming the coating layer.

Since the chlorine-containing polymer is decomposed and colored by heat, light, and ultraviolet rays, it is preferable that stearic acid such as lead, zinc, barium, silver salts, magnesium oxide, or the like is used together as a stabilizer.
Moreover, you may use antioxidant as described in Paragraph [0013]-[0020] of Unexamined-Japanese-Patent No. 2004-359819.
Furthermore, in order to increase the adhesion between the coating layer containing the chlorine-containing polymer and the transparent substrate film and other layers, Coronate L (manufactured by Nippon Polyurethane Co., Ltd.), Takenate A-3 (Takeda Pharmaceutical Co., Ltd.) It is also preferable to add 0.1 to 1.0 parts by mass of an isocyanate-based adhesive such as)) to the chlorine-containing polymer.

The mixed region formed after coating the first coating layer is the solid content concentration of the coating layer coating solution, the solvent type, the solvent composition, the additive, the type of the transparent base film on which the coating layer is coated, and the coating layer coating. It is affected by various conditions such as the amount of liquid applied, drying conditions, and curing conditions. In the present invention, the above conditions are not particularly limited as long as a mixed region is formed between the transparent substrate film and the first coating layer and there is an effect of suppressing interference unevenness of the coating layer.
The layer thickness of the mixed region is preferably in the range of 0.2 to 10 μm, more preferably 0.3 to 7 μm, and still more preferably 0.5 to 5 μm. When the thickness of the layer in the mixed region is smaller than this range, the effect of suppressing the interference unevenness of the coating layer is small, and when it is larger than this range, the strength of the coating layer tends to decrease. The thickness of the layer in the mixed region was photographed by cutting the cross section of the polarizing plate protective film using a microtome, observing in the reflected electron mode from the cross section using a scanning electron microscope (S-570, manufactured by Hitachi, Ltd.). The thickness of the layer in the mixed region can be obtained from the photograph.

[Second coating layer]
As described above, the second coating layer provided on the protective film of the present invention is preferably a coating layer formed from a resin comprising at least a vinyl alcohol polymer, and the layered inorganic in the vinyl alcohol polymer composition. A coating layer formed from a resin containing a compound is more preferable.

-I / O value of the second coating layer-
There is no restriction | limiting in particular as I / O value of a 2nd coating layer, According to the objective, it selects suitably, For example, 1.6-3.0 are preferable, 1.8-2.8 are more preferable, 2 0.0 to 2.6 is more preferable. When the I / O value exceeds 3.0, the hydrophilicity of the coating layer is high, and there is a possibility that the coating layer dissolves in a high humidity environment.
The difference between the I / O value of the second coating layer and the I / O value of the first coating layer is particularly preferably 0.5 or more.
As a method of adjusting the I / O value of the second coating layer, a method of appropriately selecting at least one of the type of monomer constituting the copolymer and the polymerization ratio (content) when the monomer is polymerized In this way, for example, the I / O value of the second coating layer can be adjusted in the range of 1.6 to 3.0.

-Vinyl alcohol polymer-
Examples of the vinyl alcohol polymer constituting the second coating layer include a homopolymer such as polyvinyl alcohol (PVA), an ethylene-vinyl alcohol copolymer (EVOH), and the like. In addition, these vinyl alcohol polymers may be partially carbonyl-modified, silanol-modified, epoxy-modified, acetoacetyl-modified, amino-modified or ammonium-modified, and a part thereof is a diacetone acrylamide unit. You may use the copolymer containing etc. Moreover, various vinyl alcohol polymers can be used alone or in combination of two or more.

  The saponification degree of the vinyl alcohol polymer can be selected from a range of 80 mol% or more, but is preferably 96 mol% or more, and more preferably 99 mol% or more. The degree of polymerization of the vinyl alcohol polymer is preferably 200 to 5,000, more preferably 400 to 5,000, and still more preferably about 500 to 3,000, from the viewpoint of moisture permeability and coatability.

-Second coating layer containing a layered inorganic compound-
In order to further reduce the moisture permeability of the second coating layer of the present invention, it is more preferable to disperse the layered inorganic compound in a binder that can be used for the second coating layer described above. Since the layered inorganic compound has a hydrophilic surface, it is preferably dispersed in a water-soluble binder, and is preferably dispersed in a coating layer made of the above-described vinyl alcohol polymer. A particularly preferable performance can be exhibited by combining with the above-mentioned preferable vinyl alcohol polymer. On the other hand, by organically treating the layered inorganic compound, it is possible to disperse in a binder having low hydrophilicity and to reduce moisture permeability.

--Layered inorganic compound--
The layered inorganic compound in the present invention is an inorganic compound having a structure in which unit crystal layers are laminated and exhibiting a property of swelling or cleaving by coordinating or absorbing a solvent between the layers.
Examples of such inorganic compounds include swellable hydrous silicates such as smectite group clay minerals (montmorillonite, saponite, hectorite, etc.), palm curite group clay minerals, kaolinite group clay minerals, phyllosilicates (mica). Etc.).
Synthetic layered inorganic compounds are also preferably used, and examples of the synthetic layered inorganic compounds include synthetic smectites (hectorite, saponite, stevensite, etc.), synthetic mica, etc., preferably smectites, montmorillonite, mica, montmorillonite, mica. Is more preferable, and mica is more preferable. Synthetic mica is particularly preferable from the viewpoint of moisture permeability reduction and suppression of coloring. Such layered inorganic compounds may be those obtained by subjecting these layered inorganic compounds to organic treatment.

The swellable layered inorganic compound is preferably finely divided from the viewpoint of achieving both the moisture permeability reduction effect and the adhesion between the easy adhesion layer and the second coating layer. The swellable layered inorganic compound that has been microparticulated is usually plate-shaped or flat-shaped, and the planar shape is not particularly limited, and may be an amorphous shape.
The average particle diameter (planar average particle diameter) of the swellable layered inorganic compound that has been microparticulated is preferably, for example, 0.1 to 10 μm, more preferably 0.5 to 8 μm, and even more preferably 0.8 to 6 μm. preferable. If the particle diameter is smaller than this range, the effect of reducing moisture permeability is not sufficient, and if the particle diameter is large, an increase in haze value, an increase in surface roughness, and the like are not preferable.
3-60 mass% is preferable, as for the density | concentration of an inorganic compound, 3-50 mass% is more preferable, and 3-40 mass% is still more preferable. If the concentration of the inorganic compound is less than 3% by mass, the effect of reducing moisture permeability is not sufficient, and if the concentration of the inorganic compound is more than 60% by mass, an increase in haze value and deterioration of brittleness are not preferable.

-Dispersion treatment of layered inorganic compound-
The layered inorganic compound is dispersed in the binder in a state where the interlayer is surely cleaved, thereby increasing the moisture transmission path length and reducing the moisture permeability.
Therefore, a dispersion treatment for obtaining a state where each layer of the layered inorganic compound is appropriately cleaved is very important.
The dispersion treatment is preferably carried out by high-pressure dispersion treatment a plurality of times in the solution. At this time, the treatment pressure is preferably 10 MPa or more, and more preferably 20 MPa or more. The solvent is not particularly specified, but water or a water-soluble solvent (lower alcohol such as methanol, ethanol, isopropyl alcohol, acetone, etc.) can be exemplified for the layered inorganic compound that has not been subjected to organic treatment, and water is particularly preferred. preferable. A mixed solvent of water and lower alcohol is also preferably used.
Examples of the high-pressure dispersion treatment method include a method in which a swellable layered inorganic compound is swollen in a solvent and then stirred by a high-pressure homogenizer to perform high-pressure dispersion.
A method for preparing the coating solution is not particularly limited, but a method of dissolving the binder component of the coating layer described above uniformly in a solvent and then mixing it with a solvent in which layered particles are uniformly dispersed is effectively used.

--Organized layered inorganic compound--
When the layered inorganic compound is dispersed in a compound having low hydrophilicity, a layered inorganic compound that can be dispersed in an organic solvent is preferably used, and a layered inorganic compound that has been subjected to an organic treatment is more preferable.
Examples of these layered inorganic compounds are layered compounds that have been organically treated with an organic agent such as alkylamine.
Further, for the purpose of further strengthening the strength of the second coating layer and further reducing moisture permeability, it is preferable to perform organic treatment with an organic agent containing a polymerizable group.
Examples of organically treated layered inorganic compounds that can be used as commercial products include Somasif MAE, MTE, MEE, and MPE (all synthetic mica manufactured by Coop Chemical Co., Ltd.), Lucentite SAN, STN, SEN, and SPN (all corp chemical). Synthetic smectite manufactured by Co., Ltd.) or the like is used.

Further, a layered inorganic compound that is not organicized, such as Lucentite ME-100 Corp. Chemical Co., Ltd. synthetic mica) or Lucentite SWN (Corp Chemical Corp. synthetic smectite) is organically treated. It is also preferable.
The organic agent is preferably a quaternary ammonium salt and is not particularly limited, but a quaternary ammonium salt represented by the following general formula (3) is more preferable.
In the following general formula (3), Ra is represented by (CH ₂ ) mH, (CH ₂ ) mRcH, or (CH ₂ Rc) mH, m is an integer of 2 or more, and Rc is any structure or none. Rb may represent CH ₃ , and n represents 0 or an integer of 1 to 3. A ⁻ represents Cl ⁻ or Br ⁻ .

In the said General formula (3), 0-3 are preferable, 0-2 are preferable, and 0-1 are especially preferable. When n is large, dispersibility deteriorates, which is not preferable. With respect to Ra, all groups may have the same structure or different structures.
m is 2 or more, and in at least one group of Ra, m is particularly preferably 4 or more, more preferably 8 or more, and further preferably 8 to 30. As m is larger, the dispersibility is better and preferable. However, when m is too large, the ratio of the organic substance to the layered inorganic compound becomes too large.

Ra also preferably has a structure in which interaction between molecules is large. Examples of the structure in which interaction between molecules is large include —OH, —CH ₂ CH ₂ O—, —CHO (CH) ₃ — and the like.
Examples of the quaternary ammonium salt include dimethyldioctadecylammonium bromide, trimethyloctadecylammonium chloride, benzyltrimethylammonium chloride, dimethylbenzyloctadecylammonium bromide, trioctylmethylammonium chloride, polyoxypropylene trimethylammonium chloride, di (polyoxypropylene) Examples thereof include dimethylammonium chloride, di (polyoxyethylene) dodecylmethylammonium chloride, tri (polyoxypropylene) methylammonium chloride, and tri (polyoxypropylene) methylammonium bromide.

As a method of using an organically treated layered inorganic compound, a method in which the layered compound is sufficiently dispersed in an organic solvent, and a solution in which a hydrophobic binder is dissolved and / or dispersed in the solvent is added. A method of adding the dispersed organically treated layered inorganic compound solution to the hydrophobic binder solution is used.
In addition, as a method of directly adding the layered inorganic compound to the hydrophobic binder, a method of adding the layered inorganic compound in a molten state of the hydrophobic binder and adding it while being dispersed in the hydrophobic binder by a method such as kneading may be used. it can.

-Other ingredients-
In the present invention, a vinyl alcohol polymer cross-linking agent may be further added as a component of the resin composition constituting the coating layer in addition to the layered inorganic compound, thereby improving the water resistance of the adhesive layer. be able to.
Moreover, you may add additives, such as a heat stabilizer, a light stabilizer, the ultraviolet absorber mentioned later, and a lubricant, to the coating layer provided in the 1st protective film of this invention as needed.

--Crosslinking agent--
The crosslinking agent is not particularly limited, and a known crosslinking agent can be appropriately selected according to the purpose. For example, phenol resin, melamine resin, urea resin, polyamide polyurea, dimethylol urea, dimethylol melamine, Epoxy compound, dialdehyde compound, polyvalent isocyanate resin, aziridine compound, polyamidoamine epichlorohydrin compound, activated vinyl compound, dicarbonate compound, hydrazino group-containing compound, colloidal silica, zirconium salt, polyvalent metal salt, boric acid, phosphorus Examples include titanium compounds such as acid, polyacrylic acid, dicarboxylic acid, adipic acid anhydride, succinic acid anhydride, tetraisopropyl titanate, and diisopropoxybis (acetylacetone) titanate. In addition, 3-glycidpropyl Methoxy Coupling agents such as orchids, the use of such radical generator such as peroxide is also possible.

  Among the above crosslinking agents, activated vinyl compounds, dicarbonate compounds, colloidal silica, zirconium salts, polyvalent metal salts, boric acid, phosphoric acid, polyacrylic acid, dicarboxylic acid, adipic acid anhydride, succinic acid anhydride, Titanium compounds such as tetraisopropyl titanate and diisopropoxybis (acetylacetone) titanate are preferable because of excellent balance between viscosity and adhesive strength.

  The addition amount of the crosslinking agent is preferably 0.5% by mass or more, more preferably 1% by mass or more, and particularly preferably 2% by mass or more in terms of (crosslinking agent / (PVA polymer + crosslinking agent)). In the case where the mass ratio of the crosslinking agent to both the PVA polymer and the crosslinking agent is less than 0.5% by mass, the effect is not exhibited by adding the crosslinking agent. The mass ratio of the crosslinking agent to both the PVA polymer and the crosslinking agent is preferably 50% by mass or less, more preferably 40% by mass or less, and particularly preferably 30% by mass or less. When the mass ratio of the crosslinking agent exceeds 50% by mass, the transparency and water resistance of the adhesive layer formed from the resin composition tend to decrease.

<< Easily Adhesive Layer >>
In the present invention, it is preferable to form an easy adhesion layer in order to improve the adhesion between the first coating layer and the second coating layer.
As the easy adhesion layer, in order to improve the adhesion between the first coating layer and the second coating layer, the I / O value of the easy adhesion layer is the I of the first coating layer to be bonded. If it is a numerical value between the / O value and the I / O value of the second coating layer that is also the object to be bonded, there is no particular limitation, and it is appropriately selected according to the purpose. For example, easy adhesion made of polymer latex A layer, an easy-adhesion layer made of a hydrophilic polymer compound, an easy-adhesion layer combining these, and the like are used.
These easy adhesion layers may be laminated directly on the first coating layer, or may be laminated after performing an easy adhesion treatment such as a saponification treatment or a corona discharge treatment.

[Easily adhesive layer made of polymer latex]
The easy adhesion layer is preferably made of a polymer latex.
The “polymer latex” referred to in the present invention is a polymer in which a water-insoluble hydrophobic polymer is dispersed as fine particles in a water-soluble dispersion medium.
As the dispersion state, the polymer is emulsified in a dispersion medium, emulsion-polymerized, micelle-dispersed, or partly hydrophilic in the polymer molecule and the molecular chain itself is molecularly dispersed. Any of these may be used.
For the polymer latex used in the present invention, “Synthetic Resin Emulsion (Hiraku Okuda, Hiroshi Inagaki, published by Kobunshi Publishing Co., Ltd. (1978))”, “Application of Synthetic Latex (Takaaki Sugimura, Ikuo Kataoka, Junichi Suzuki, Kasahara) Edited by Keiji, published by Polymer Press (1993)), "chemistry of synthetic latex (by Soichi Muroi, published by Polymer Press (1970))" and the like. The average particle size of the dispersed particles is preferably 1 to 50000 nm, and more preferably 5 to 1000 nm. The particle size distribution of the dispersed particles is not particularly limited, and may have a wide particle size distribution or a monodispersed particle size distribution.

The polymer latex used in the present invention may be a normal uniform structure polymer latex or a so-called core / shell type latex.
In the case of the core / shell type, it may be preferable that the glass transition temperatures of the core and the shell are different.

  The glass transition temperature (Tg) of the polymer latex preferably used for the binder used in the present invention is preferably −30 to 80 ° C., more preferably −15 to 70 ° C., and 0 ° C. to 60 ° C. Is particularly preferred.

The minimum film-forming temperature (MFT) of the polymer latex used in the present invention is preferably -30 ° C to 90 ° C, more preferably about 0 ° C to 70 ° C. A film-forming auxiliary may be added to control the minimum film-forming temperature. The film-forming aid is also called a plasticizer and is an organic compound (usually an organic solvent) that lowers the minimum film-forming temperature of the polymer latex. For example, it is described in “Synthetic Latex Chemistry (Muroichi Muroi, published by Kobunshi Shuppankai (1970))”. Specific examples of the film forming aid include the following compounds.
K-1: benzyl alcohol K-2: 2-dimethylaminoethanol K-3: 2,2,4-trimethylpentanediol-1,3-monoisobutyrate K-4: diacetone alcohol K-5: ethylene glycol Monobutyl ether K-6: Diethylene glycol monobutyl ether acetate K-7: Dibutyl phthalate K-8: Diethylene glycol

Examples of the polymer species used in the polymer latex used in the present invention include acrylic resins, vinyl acetate resins, polyester resins, polyurethane resins, rubber resins, vinyl chloride resins, vinylidene chloride resins, polyolefin resins, and copolymers thereof. Can be mentioned.
The polymer may be a linear polymer, a branched polymer, or a crosslinked polymer. The polymer may be a so-called homopolymer obtained by polymerizing a single monomer, or a copolymer obtained by polymerizing two or more monomers. In the case of a copolymer, it may be a random copolymer or a block copolymer. The molecular weight of the polymer is 5,000 to 1,000,000, preferably about 10,000 to 100,000 in terms of number average molecular weight. If the molecular weight is too small, the mechanical strength of the image forming layer is insufficient, and if it is too large, the film formability is poor, which is not preferable.

Specific examples of the polymer latex used as the binder of the easy adhesion layer of the present invention include methyl methacrylate / ethyl acrylate / methacrylic acid copolymer latex, methyl methacrylate / butadiene / itaconic acid copolymer latex, and ethyl acrylate / methacrylic acid copolymer. Latex, latex of methyl methacrylate / 2-ethylhexyl acrylate / styrene / acrylic acid copolymer, latex of styrene / butadiene / acrylic acid copolymer, latex of styrene / butadiene / divinylbenzene / methacrylic acid copolymer, methyl methacrylate / vinyl chloride / acrylic acid copolymer And latex of vinylidene chloride / ethyl acrylate / acrylonitrile / methacrylic acid copolymer. More specifically, copolymer latex of methyl methacrylate / ethyl acrylate / methacrylic acid = 33.5 / 50 / 16.5 (mass%), copolymer latex of methyl methacrylate / butadiene / itaconic acid = 47.5 / 47.5 / 5 (mass%), ethyl Examples thereof include copolymer latex of acrylate / methacrylic acid = 95/5 (mass%). Such polymers are also commercially available, for example, as an example of acrylic resin, Sebian A-4635, 46583, 4601 (above Daicel Chemical Industries, Ltd.), Nipol LX811, 814, 821, 820, 857 ( As a polyester resin, FINETEX ES650, 611, 675, 850 (Dainippon Ink Chemical Co., Ltd.) (Made by Co., Ltd.), WD-size, WMS (made by Eastman Chemical Co., Ltd.) etc., polyurethane resins such as HYDRAN AP10, 20, 30, 40 (made by Dainippon Ink Chemical Co., Ltd.), etc. G351, G576 (Japan) As a vinylidene chloride resin such as Zeon Corporation), L502, L529B described in the first coating layer, 536B, L544D, L549B, L551B, L557, L561A, L116A, L411A, L120, L123D, L106C, L131A, L111, L232A, L321B (above Asahi Kasei Kogyo Co., Ltd.), Aaron D7020, D504, D5071 Examples of the olefin resin include Chemipearl S120 and SA100 (manufactured by Mitsui Petrochemical Co., Ltd.).
These polymers may be used alone or in combination of two or more as required.

  The easy-adhesion layer of the present invention is preferably prepared by applying an aqueous coating solution and then drying it. However, “aqueous” as used herein means that 60% by mass or more of the solvent (dispersion medium) of the coating solution is water. As components other than water in the coating solution, water-miscible organic solvents such as methyl alcohol, ethyl alcohol, isopropyl alcohol, methyl cellosolve, ethyl cellosolve, dimethylformamide, and ethyl acetate can be used. Specific examples of the solvent composition include the following. Water / methanol = 90/10, water / methanol = 70/30, water / ethanol = 90/10, water / isopropanol = 90/10, water / dimethylformamide = 95/5, water / methanol / dimethylformamide = 80 / 15/5, water / methanol / dimethylformamide = 90/5/5 (however, the number represents mass%)

[Adhesive layer composed of hydrophilic polymer compound]
In the present invention, an easy-adhesion layer containing a hydrophilic polymer compound as a main binder can be provided on the first coating layer.

  Here, as the hydrophilic polymer compound, generally, a polymer compound having a hydrophilic group such as a hydroxyl group may be used, and acylated gelatin such as gelatin, phthalated gelatin, maleated gelatin, methyl cellulose, carboxymethyl cellulose, Cellulose derivatives such as hydroxyethyl cellulose, grafted gelatin obtained by grafting acrylic acid, methacrylic acid or amide onto gelatin, polyvinyl alcohol derivatives (for example, polyvinyl alcohol, vinyl acetate-vinyl alcohol copolymer, polyvinyl acetate, polyvinyl acetal, Polyvinyl homar, polyvinyl benzal, etc.), natural polymer compounds (eg, gelatin, casein, gum arabic, agar, starch, etc.), hydrophilic polyester derivatives (eg, partially sulfonated) Poly (N-vinylpyrrolidone, copoly-vinylpyrrolidone-vinyl acetate, polyacrylamide, polyvinylimidazole, polyvinylpyrazole, etc.), polyhydroxyalkyl acrylate, grafted starch, agarose, albumin, sodium alginate Polysaccharide polyacrylamide, N-substituted acrylamide, N-substituted methacrylamide or the like alone or a copolymer, or a partial hydrolyzate thereof, or a synthetic or natural hydrophilic polymer compound is used. These are used alone or in combination.

As the hydrophilic polymer compound, a polyvinyl alcohol derivative (for example, polyvinyl alcohol) having a composition similar to that of the second coating layer is preferable.
When polyvinyl alcohol is used, the degree of polymerization is preferably 100 to 7,000, more preferably 300 to 5,000, still more preferably 500 to 5,000, and 1,000 to 4,000 is particularly preferred.
The degree of saponification is preferably 40 to 99.9%, more preferably 50 to 99.5%, and particularly preferably 60 to 99.

  Moreover, a crosslinking agent is also preferably used for the easy adhesion layer. The crosslinking agent is selected from epoxy compounds, isocyanate compounds, blocked isocyanate compounds, methylol compounds, hydroxy compounds, carboxyl compounds, amino compounds, ethyleneimine compounds, aldehyde compounds, halogen compounds, and the like. Specific examples of the cross-linking agent include hexamethylene isocyanate, duranate WB40-80D, WX-1741 (manufactured by Asahi Kasei Kogyo Co., Ltd.), Bihijoule 3100 (manufactured by Sumitomo Bayer Urethane Co., Ltd.), Takenate WD725 (Takeda Pharmaceutical Co., Ltd.) Aquanate 100, 200 (manufactured by Nippon Polyurethane Co., Ltd.), water-dispersed polyisocyanate described in JP-A-9-160172; Sumitex Resin M-3 (Sumitomo Chemical Co., Ltd.) 2,4-dichloro-6-hydroxy-1,3,5-triazine sodium and the like as the halogen compound.

Examples of the epoxy compound include 1,4-bis (2 ′, 3′-epoxypropyloxy) butane, 1,3,5-triglycidyl isocyanurate, 1,3-diglycidyl-5- (γ-acetoxy-β-oxy Propyl) isosinurate, sorbitol polyglycidyl ethers, polyglycerol polyglycidyl ethers, pentaerythritol polyglycidyl ethers, diglycerol polyglycidyl ether, 1,3,5-triglycidyl (2-hydroxyethyl) isocyanurate, glycerol poly Epoxy compounds such as glycerol ethers and trimethylolpropane polyglycidyl ethers are preferable, and specific commercial products thereof include, for example, Denacol EX-521 and EX-614B (manufactured by Nagase Kasei Kogyo Co., Ltd.). , But it is not limited thereto.
In addition, in the range of the addition amount that does not affect the optical characteristics, it can be used in combination with other compounds. E. K. Meers and T.W. H. "The Theory of the Photographic Process" by James, 3rd edition (1966), U.S. Patent Nos. 3316095, 3232264, 3288775, 27332303, 3635718, 3323716, 2732616, 258616 No. 3103437, No. 3017280, No. 2998611, No. 2725294, No. 2725295, No. 3100704, No. 3091537, No. 3321313, No. 3543292 and No. 312449, and British Patent No. 994869, and Examples thereof include curing agents described in No. 1167207 and the like.
Typical examples include melamine compounds containing two or more (preferably three or more) methylol groups and / or alkoxymethyl groups, and melamine resins or melamine urea resins, mucochloric acid, which are polycondensates thereof. Mucobromic acid, mucofenoxycyclolic acid, mucophenoxypromic acid, formaldehyde, glyoxal, monomethylglioxal, 2,3-dihydroxy-1,4-dioxane, 2,3-dihydroxy-5-methyl-1,4-dioxanesuccin Aldehyde compounds such as aldehyde, 2,5-dimethoxytetrahydrofuran and glutaraldehyde and derivatives thereof; divinylsulfone-N, N′-ethylenebis (vinylsulfonylacetamide), 1,3-bis (vinylsulfonyl) -2-propanol, Methylenebis Maleimide, 5-acetyl-1,3-diacryloyl-hexahydro-s-triazine, 1,3,5-triacryloyl-hesahydro-s-triazine, 1,3,5-trivinylsulfonyl-hexahydro-s-triazine, etc. 2,4-dichloro-6-hydroxy-s-triazine sodium salt, 2,4-dichloro-6- (4-sulfoanilino) -s-triazine sodium salt, 2,4-dichloro-6 Active halogen compounds such as (2-sulfoethylamino) -s-triazine and N, N′-bis (2-chloroethylcarbamyl) piperazine; bis (2,3-epoxypropyl) methylpropylammonium · p-toluene Sulfonate, 2,4,6-triethylene-s-triazine, 1,6-hexamethylene-N, Ethyleneimine compounds such as N′-bisethyleneurea and bis-β-ethyleneiminoethylthioether; 1,2-di (methanesulfoneoxy) ethane, 1,4-di (methanesulfoneoxy) butane and 1,5- Methanesulfonic acid ester compounds such as di (methanesulfoneoxy) pentane; carbodiimide compounds such as dicyclohexylcarbodiimide and 1-dicyclohexyl-3- (3-trimethylaminopropyl) carbodiimide hydrochloride; isoforms such as 2,5-dimethylisoxazole Oxazole compounds; inorganic compounds such as chromium alum and chromium acetate; N-carboethoxy-2-isopropoxy-1,2-dihydroquinoline and N- (1-morpholinocarboxy) -4-methylpyridinium chloride Dehydrated condensation type peptide reagent; N, Active ester compounds such as' -adipoyldioxydisuccinimide and N, N'-terephthaloyldioxydisuccinimide: isocyanates such as toluene-2,4-diisocyanate and 1,6-hexamethylene diisocyanate; and An epichlorohydrin compound such as a polyamide-polyamine-epichlorohydrin reactant may be used, but the present invention is not limited thereto.

  As a thickness of an easily bonding layer, the range of 0.05-1.0 micrometer is preferable. If it is thinner than 0.05 μm, it is difficult to obtain sufficient adhesiveness, and if it is thicker than 1.0 μm, the adhesive effect is saturated.

  An ultraviolet absorber described later can be added to the easy-adhesion layer as necessary.

  Depending on the desired purpose of the coating solution, for example, water-soluble polymers other than those described above, surfactants, antifoaming agents and the like can be appropriately mixed. In preparing a coating solution containing these, it is preferable to prepare respective aqueous solutions whose concentrations are adjusted as appropriate, and then mix them to prepare a coating solution. When preparing each aqueous solution, it may be dissolved by heating in order to enhance the solubility.

(Polarizer)
FIG. 2 is a cross-sectional view showing the configuration of the polarizing plate in the present embodiment. As shown in FIG. 2, the polarizing plate 5 of the present embodiment is a polarizer 6 and a first protective film that is provided on one surface of the polarizer 6 and has a plurality of coating layers 3 (for the polarizing plate described above). Protective film) 1 and a second protective film 7 provided on the other surface of the polarizer 6 (a surface opposite to one surface of the polarizer 6).
The first protective film 1 is bonded to the polarizer 6 so that the coating layer 3 provided on the first protective film 1 faces the polarizer 6.
The material of the second protective film 7 is not particularly limited and is appropriately selected depending on the purpose. From the viewpoint of productivity, a transparent base film made of cellulose acylates having no coating layer formed. It is preferable that

<First protective film>
<< Transparent substrate film (substrate layer) >>
As a base material layer of the first protective film, it is sufficient that moisture permeability and equilibrium water content are within a desired range, and the composition includes cellulose resin, polyester resin, polycarbonate resin, saturated alicyclic structure-containing polymer. A resin such as a resin, an acrylic resin, a melamine resin, or a polyethylene resin can be used, and it is preferably made of a cellulose resin or a saturated alicyclic structure-containing polymer resin, and is a cellulose acylate film made of a cellulose resin. Is more preferable.

[Cellulose acylate film]
As the base layer of the first protective film, a cellulose acylate film is used because it is optically uniform, has a smooth surface, and has good secondary workability in producing a polarizing plate. It is preferable.
The cellulose acylate used for the first protective film is an aliphatic carboxylic acid ester or an aromatic carboxylic acid ester having about 2 to 22 carbon atoms, and is particularly preferably a lower fatty acid ester of cellulose.
The lower fatty acid in the lower fatty acid ester of cellulose means a fatty acid having 6 or less carbon atoms. For example, cellulose acetate, cellulose propionate, cellulose butyrate, cellulose acetate phthalate, etc., and JP-A-10-45804 Mixed fatty acid esters such as cellulose acetate propionate and cellulose acetate butyrate as described in JP-A-8-2311761, US Pat. No. 2,190,052 and the like are used. Alternatively, esters of aromatic carboxylic acids and cellulose described in JP-A Nos. 2002-179701, 2002-265639, and 2002-265638 are also preferably used.
Among the above description, the lower fatty acid esters of cellulose that are particularly preferably used are cellulose triacetate and cellulose acetate propionate described later. These cellulose esters can also be mixed and used.

The degree of substitution (DS) of cellulose acylate means the ratio of acylation of three hydroxyl groups present in the cellulose structural unit (glucose having β1 → 4 glycosidic bonds).
The degree of substitution can be calculated by measuring the amount of bound fatty acid per unit mass of cellulose. The measurement method is carried out according to ASTM-D817-91.
The cellulose acylate of the present invention balances the humidity dependence of the retardation and the dimensional stability by appropriately balancing the hydrophobicity of the acyl group and the hydrophilicity of the hydroxyl group.
That is, if the alkyl chain in the acyl group is too short on average or the hydroxyl group ratio is too high, the humidity dependency of retardation will increase.
On the other hand, if the alkyl chain in the acyl group is too long on average or the hydroxyl group ratio is too high, the Tg is lowered and the dimensional stability is deteriorated.
Accordingly, the cellulose triacetate preferably used in the present invention preferably has a degree of acetylation of 2.83 or more and 2.91 or less and no other acyl group having 3 or more carbon atoms, and the degree of acetylation is 2.84 or more and 2 .89 or less is more preferable.

  In addition, cellulose ester other than cellulose triacetate has an acyl group having 2 to 4 carbon atoms as a substituent, the substitution degree of acetyl group is X, and the substitution degree of propionyl group is Y, the following formula ( It is a cellulose ester that satisfies both a) and (b).

2.6 ≦ X + Y ≦ 2.9 Equation (a)
0 ≦ X ≦ 2.5 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Formula (b)

  Here, among the cellulose esters that simultaneously satisfy the formulas (a) and (b), cellulose acetate propionate (total acyl group) of 1.9 ≦ X ≦ 2.5 and 0.1 ≦ Y ≦ 0.9 Degree of substitution = X + Y) is preferred. The portion not substituted with an acyl group usually exists as a hydroxyl group. These can be synthesized by known methods.

  30-120 micrometers is preferable and, as for the thickness of the said transparent base film, 40-80 micrometers is more preferable. If the thickness of the substrate film is 30 μm or more, problems such as a decrease in film strength are unlikely to occur, and if it is 120 μm or less, the mass increases excessively, which is disadvantageous particularly when used for a large television of 20 inches or more. This is preferable because it does not easily cause harmful effects such as.

-UV absorber-
Any of the transparent substrate film, the coating layer, the easy-adhesion layer, and the hard coat layer described later preferably contains one or more ultraviolet absorbers represented by the following general formula (1).
In the following general formula (1), R ¹ , R ² , R ³ , R ⁴ and R ⁵ each independently represent a hydrogen atom or a monovalent organic group, and at least one of R ¹ , R ² and R ³ Represents an unsubstituted branched or straight chain alkyl group having 4 to 20 carbon atoms in total, and R ¹ , R ² and R ³ are different from each other.

Further, an average value (hereinafter sometimes referred to as “log P”) of octanol / water distribution coefficient (hereinafter sometimes referred to as “log P”) represented by the following formula (c) relating to the ultraviolet absorber, and cellulose acylate. More preferably, a cellulose acylate film having a degree of acylation DS of the following formula (d) is used as the transparent substrate film.
Here, in the following mathematical formula (c), W _n represents the mass fraction of the nth ultraviolet absorber, and (logP) _n represents “logP” of the nth ultraviolet absorber.

5.0 × DS−6.7 ≦ average log P ≦ 5.0 × DS−5.1... (D)

The average value of the log P of the ultraviolet absorbent used in the present invention is preferably (5.0 × DS-6.7) or more and (5.0 × DS-5.1) or less, (5.0 × DS -6.5) or more and (5.0 × DS-5.2) or less are more preferable.
If the average value of log P is too large, the surface shape is deteriorated, and if the average value of log P is too small, the retentivity of the ultraviolet absorbent under high temperature and high humidity is deteriorated.
Moreover, the compound represented by General formula (1) has an absorption maximum in the wavelength range of 330-360 nm.

--Log P value--
Here, the octanol-water partition coefficient (log P value) can be measured by a flask immersion method described in JIS Japanese Industrial Standard Z7260-107 (2000).
Further, the octanol-water partition coefficient (log P value) can be estimated by a computational chemical method or an empirical method instead of the actual measurement.
As a calculation method, Crippen's fragmentation method (J. Chem. Inf. Comput. Sci., 27, 21 (1987)), Viswanadhan's fragmentation method (J. Chem. Inf. Comput. Sci., 29, 163). (1989)), Broto's fragmentation method (Eur. J. Med. Chem.-Chim. Theor., 19, 71 (1984)) and the like are preferably used, but the Crippen's fragmentation method (J. Chem. Inf .Comput.Sci., 27, 21 (1987)) is more preferable.
When the log P value of a certain compound varies depending on the measurement method or calculation method, it is preferable to determine whether or not the compound is within the scope of the present invention by the Crippen's fragmentation method.

The UV absorber preferably has a molecular weight of 250 to 1,000 from the viewpoint of volatility, more preferably 260 to 800, still more preferably 270 to 800, and 300 to 800. Is particularly preferred.
A specific monomer structure may be used as long as these molecular weights are within the range, and an oligomer structure or a polymer structure in which a plurality of the monomer units are bonded may be used.
Moreover, it is preferable that the said ultraviolet absorber does not volatilize in the process of dope casting of cellulose acylate film preparation, the process of drying, the coating layer, the easily adhesive layer, the layer having hard coat properties, and the like, and the process of drying.

--- Amount of UV absorber added--
The amount of the ultraviolet absorber used in the present invention described above is preferably 0.01 to 10% by mass, more preferably 0.1 to 5% by mass, based on cellulose acylate. More preferably, it is 0.2-3 mass%.
When added to a coating layer, an easy-adhesion layer, a layer having hard coat properties, etc., it is preferably 0.01 to 10% by mass, and 0.1 to 5% by mass with respect to the total solid content. Is more preferable, and 0.2 to 3% by mass is particularly preferable.

--- Adding method of UV absorber ---
Further, the timing of adding these ultraviolet absorbers may be any time during the dope and coating layer preparation step, or may be performed at the end of the dope and coating layer preparation step.

Next, the said ultraviolet absorber represented by General formula (1) is demonstrated in detail.
R ¹ , R ² , R ³ , R ⁴ , and R ⁵ each independently represent a hydrogen atom or a monovalent organic group, and at least one of R ¹ , R ² , and R ³ has a total carbon number of 4 Represents an unsubstituted or branched alkyl group of -20, and R ¹ , R ² , and R ³ are different from each other.
Examples of the substituent include an alkyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, particularly preferably 1 to 8 carbon atoms, such as methyl, ethyl, iso-propyl, tert-butyl, and n-octyl, n-decyl, n-hexadecyl, cyclopropyl, cyclopentyl, cyclohexyl, etc.), an alkenyl group (preferably having 2 to 20 carbon atoms, more preferably 2 to 12 carbon atoms, and particularly preferably carbon number). 2 to 8, for example, vinyl, allyl, 2-butenyl, 3-pentenyl, etc.), an alkynyl group (preferably having 2 to 20 carbon atoms, more preferably 2 to 12 carbon atoms, and particularly preferably carbon number). 2-8, for example, propargyl, 3-pentynyl, etc.), aryl groups (preferably having 6-30 carbon atoms) More preferably, it has 6 to 20 carbon atoms, particularly preferably 6 to 12 carbon atoms, and examples thereof include phenyl, p-methylphenyl, naphthyl and the like, and a substituted or unsubstituted amino group (preferably having 0 to 0 carbon atoms). 20, more preferably 0 to 10 carbon atoms, particularly preferably 0 to 6 carbon atoms, and examples thereof include amino, methylamino, dimethylamino, diethylamino, dibenzylamino and the like.

In addition, other examples of the substituent include an alkoxy group (preferably having 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, and particularly preferably 1 to 8 carbon atoms, and examples thereof include methoxy, ethoxy, and butoxy. An aryloxy group (preferably having 6 to 20 carbon atoms, more preferably 6 to 16 carbon atoms, particularly preferably 6 to 12 carbon atoms, and examples thereof include phenyloxy and 2-naphthyloxy). An acyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, and examples thereof include acetyl, benzoyl, formyl, pivaloyl and the like), an alkoxycarbonyl group. (Preferably having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, and particularly preferably 2 to 12 carbon atoms. And aryloxycarbonyl groups (preferably having 7 to 20 carbon atoms, more preferably 7 to 16 carbon atoms, particularly preferably 7 to 10 carbon atoms, such as phenyloxycarbonyl). An acyloxy group (preferably having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, and particularly preferably 2 to 10 carbon atoms, such as acetoxy and benzoyloxy). (Preferably having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, particularly preferably 2 to 10 carbon atoms, and examples thereof include acetylamino and benzoylamino), alkoxycarbonylamino group (preferably carbon 2 to 20, more preferably 2 to 16 carbon atoms, particularly preferably 2 to 1 carbon atoms Such as methoxycarbonylamino), aryloxycarbonylamino group (preferably having 7 to 20 carbon atoms, more preferably having 7 to 16 carbon atoms, particularly preferably having 7 to 12 carbon atoms, such as phenyl Oxycarbonylamino, etc.), sulfonylamino groups (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as methanesulfonylamino, benzenesulfonylamino) ), A sulfamoyl group (preferably having 0 to 20 carbon atoms, more preferably 0 to 16 carbon atoms, and particularly preferably 0 to 12 carbon atoms. For example, sulfamoyl, methylsulfamoyl, dimethylsulfamoyl , Phenylsulfamoyl, etc.), carbamoyl Group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, and examples thereof include carbamoyl, methylcarbamoyl, diethylcarbamoyl, phenylcarbamoyl and the like. ), An alkylthio group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as methylthio, ethylthio, etc.), an arylthio group (preferably carbon 6 to 20, more preferably 6 to 16 carbon atoms, particularly preferably 6 to 12 carbon atoms, such as phenylthio, and the like, and a sulfonyl group (preferably 1 to 20 carbon atoms, more preferably carbon atoms). 1 to 16, particularly preferably 1 to 12 carbon atoms such as mesyl, tosyl, etc.), sulfinyl group (preferably 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably carbon atoms). 1 to 12, for example, methanesulfinyl, benzenesulfinyl, etc.), ureido group (preferably having 1 to 1 carbon atoms) 0, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as ureido, methylureido, phenylureido, etc.), phosphoric acid amide group (preferably having 1 to 20 carbon atoms, More preferably, it has 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, and examples thereof include diethyl phosphoric acid amide and phenyl phosphoric acid amide), hydroxy group, mercapto group, halogen atom (for example, fluorine atom, Chlorine atom, bromine atom, iodine atom), cyano group, sulfo group, carboxyl group, nitro group, hydroxamic acid group, sulfino group, hydrazino group, imino group, heterocyclic group (preferably having 1 to 30 carbon atoms, more preferably 1 to 12 and the hetero atom includes, for example, a nitrogen atom, an oxygen atom, a sulfur atom, specifically, for example, an imidazoli , Pyridyl, quinolyl, furyl, piperidyl, morpholino, benzoxazolyl, benzimidazolyl, benzthiazolyl, etc.), a silyl group (preferably having 3 to 40 carbon atoms, more preferably 3 to 30 carbon atoms, particularly preferably Are those having 3 to 24 carbon atoms, and examples thereof include trimethylsilyl and triphenylsilyl). These substituents may be further substituted.
Further, when there are two or more substituents, they may be the same or different, and may be connected to each other to form a ring if possible, but at least one of R ¹ , R ² and R ³ is It represents an unsubstituted branched or straight chain alkyl group having a total carbon number of 4 to 20, and R ¹ , R ² , and R ³ are different from each other.

R ¹ and R ³ are preferably a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, a substituted or unsubstituted amino group, an alkoxy group, an aryloxy group, a hydroxy group, or a halogen atom, a hydrogen atom, an alkyl group Group, an aryl group, an alkyloxy group, an aryloxy group, and a halogen atom are more preferable, a hydrogen atom, and an alkyl group having 1 to 12 carbon atoms are more preferable, and an alkyl group having 1 to 12 carbon atoms (preferably having 4 to 12 carbon atoms). Particularly preferred.

R ² is preferably a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, a substituted or unsubstituted amino group, an alkoxy group, an aryloxy group, a hydroxy group, or a halogen atom, a hydrogen atom, an alkyl group, An aryl group, an alkyloxy group, an aryloxy group and a halogen atom are more preferable, a hydrogen atom and a carbon 1-12 alkyl group are further preferable, a hydrogen atom and a methyl group are particularly preferable, and a hydrogen atom is most preferable.

R ⁴ and R ⁵ are preferably a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, a substituted or unsubstituted amino group, an alkoxy group, an aryloxy group, a hydroxy group, or a halogen atom, a hydrogen atom, An alkyl group, an aryl group, an alkyloxy group, an aryloxy group and a halogen atom are more preferred, a hydrogen atom and a halogen atom are further preferred, and a hydrogen atom and a chlorine atom are particularly preferred.

  Although the specific example of a compound represented by General formula (1) below is given, this invention is not limited to the following specific example at all.

-Plasticizer-
Examples of the plasticizer that can be used for the transparent substrate film of the present invention include polyhydric alcohol ester plasticizers, glycolate plasticizers, phosphate ester plasticizers, and phthalate ester plasticizers. Particularly preferred are polyhydric alcohol plasticizers and glycolate plasticizers.
Moreover, it is preferable to set it as 16 mass% or less with respect to a film, as for the addition amount of a phosphate ester plasticizer, it is more preferable to set it as 10 mass% or less, and it is still more preferable to set it as 6 mass% or less.

  The polyhydric alcohol ester is composed of an ester of a dihydric or higher aliphatic polyhydric alcohol and a monocarboxylic acid, and preferably has an aromatic ring or a cycloalkyl ring in the molecule.

The polyhydric alcohol used in the present invention is represented by the following general formula (2).
However, in the following general formula (2), R ₁ represents an n-valent organic group, n represents a positive integer of 2 or more, and an OH group represents an alcoholic and / or phenolic hydroxyl group.

Examples of the polyhydric alcohol represented by the general formula (2) include the following, but the present invention is not limited to these.
Specifically, adonitol, arabitol, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propanediol, 1,3-propanediol, dipropylene glycol, tripropylene glycol, 1,2-butanediol 1,3-butanediol, 1,4-butanediol, dibutylene glycol, 1,2,4-butanetriol, 1,5-pentanediol, 1,6-hexanediol, hexanetriol, galactitol, mannitol, Examples include 3-methylpentane-1,3,5-triol, pinacol, sorbitol, trimethylolpropane, trimethylolethane, and xylitol.
Among these, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, sorbitol, trimethylolpropane, and xylitol are particularly preferable.

  There is no restriction | limiting in particular as monocarboxylic acid used for the polyhydric alcohol ester of this invention, Well-known aliphatic monocarboxylic acid, alicyclic monocarboxylic acid, aromatic monocarboxylic acid, etc. are used. Among these, alicyclic monocarboxylic acid and aromatic monocarboxylic acid are preferable in terms of improving moisture permeability and retention.

  Examples of preferred monocarboxylic acids include the following, but the present invention is not limited thereto.

  As the aliphatic monocarboxylic acid, a fatty acid having a straight chain or a side chain having 1 to 32 carbon atoms is preferably used, and among them, the number of carbon atoms is more preferably 1 to 20, and the number of carbon atoms is preferably 1 to 2. More preferably, it is 10. When acetic acid is contained, the compatibility with the cellulose ester is increased, and it is also preferable to use a mixture of acetic acid and another monocarboxylic acid.

  Preferred aliphatic monocarboxylic acids include acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, 2-ethyl-hexanecarboxylic acid, undecylic acid, lauric acid, tridecylic acid , Saturated fatty acids such as myristic acid, pentadecylic acid, palmitic acid, heptadecylic acid, stearic acid, nonadecanoic acid, arachidic acid, behenic acid, lignoceric acid, serotic acid, heptacosanoic acid, montanic acid, melicic acid, laccelic acid, undecylenic acid, And unsaturated fatty acids such as oleic acid, sorbic acid, linoleic acid, linolenic acid and arachidonic acid.

  Examples of preferred alicyclic monocarboxylic acids include cyclopentane carboxylic acid, cyclohexane carboxylic acid, cyclooctane carboxylic acid, or derivatives thereof.

  Examples of preferred aromatic monocarboxylic acids include those in which an alkyl group is introduced into the benzene ring of benzoic acid such as benzoic acid and toluic acid, and two or more benzene rings such as biphenylcarboxylic acid, naphthalenecarboxylic acid, and tetralincarboxylic acid. The aromatic monocarboxylic acid which has, or those derivatives are mentioned. Among these, benzoic acid is particularly preferable.

  The molecular weight of the polyhydric alcohol ester is not particularly limited, but is preferably 300 to 1,500, and more preferably 350 to 750. A higher molecular weight is preferable because it is less likely to volatilize, and a lower molecular weight is preferable in terms of moisture permeability and compatibility with cellulose ester.

  The carboxylic acid used for the polyhydric alcohol ester may be one kind or a mixture of two or more kinds. Moreover, all the OH groups in the polyhydric alcohol may be esterified, or a part of the OH groups may be left as they are.

The specific compound of a polyhydric alcohol ester is shown below.

The glycolate plasticizer is not particularly limited, but a glycolate plasticizer having an aromatic ring or a cycloalkyl ring in the molecule is preferably used.
As a preferable glycolate type plasticizer, for example, butylphthalylbutyl glycolate, ethylphthalylethyl glycolate, methylphthalylethyl glycolate or the like is used.

As the phosphate ester plasticizer, triphenyl phosphate, tricresyl phosphate, cresyl diphenyl phosphate, octyl diphenyl phosphate, diphenyl biphenyl phosphate, trioctyl phosphate, tributyl phosphate and the like are used.
Further, as phthalate ester plasticizers, diethyl phthalate, dimethoxyethyl phthalate, dimethyl phthalate, dioctyl phthalate, dibutyl phthalate, di-2-ethylhexyl phthalate, butyl benzyl phthalate, dibenzyl phthalate, butyl phthalyl butyl glycolate, ethyl Phthalyl ethyl glycolate, methyl phthalyl ethyl glycolate or the like is used.
Examples of the citrate ester plasticizer include triethyl citrate, tri-n-butyl citrate, acetyl triethyl citrate, acetyl tri-n-butyl citrate, acetyl tri-n- (2-ethylhexyl) citrate and the like. Used.

  These plasticizers can be used alone or in combination of two or more. 4-20 mass% is preferable with respect to a cellulose ester, and, as for the usage-amount of a plasticizer, 6-16 mass% is more preferable, and 8-13 mass% is still more preferable. If the added amount of the plasticizer is too large, the film becomes too soft and the water absorption modulus decreases. If the added amount is too small, the moisture permeability of the film decreases.

  In addition to the plasticizers described above, various additives are used in the transparent base film of the present invention for the purpose of controlling film properties such as durability, moisture permeability, and elastic modulus of the substrate, and optical property values. For example, JP 2006-30937 A (paragraph numbers [0054] to [0134]), JP 2003-12859 A, JP 2002-20410 A, JP 2003-222723 A (paragraph). Nos. [0031] to [0044]) and compounds described in JP-A-2002-22756 (paragraph numbers [0045] to [0058]) can be used.

<< Hard coat layer >>
In the first protective film of the present invention, a layer having a hard coat property on one surface of the transparent substrate film (hereinafter sometimes referred to as a hard coat layer) in order to impart physical strength of the protective film. Is preferably provided.
The coating surface of the layer having hard coat properties is not particularly limited, but in consideration of application suitability, it may be applied directly to the base material layer (on the side opposite to the coating layer via the base material layer). preferable.
Further, it is more preferable that a low refractive index layer is provided on the hard coat layer, and an antireflective film is formed by providing an intermediate refractive index layer and a high refractive index layer between the hard coat layer and the low refractive index layer. More preferably. The hard coat layer may be composed of a laminate of two or more layers.

  The refractive index of the hard coat layer in the present invention is preferably 1.48 to 2.00, more preferably 1.49 to 1.90 from the optical design for obtaining an antireflection film. Is more preferable, and it is still more preferable that it is 1.50-1.80.

The thickness of the hard coat layer is preferably about 0.5 μm to 50 μm, more preferably 1 to 20 μm, still more preferably 2 to 15 μm, from the viewpoint of imparting sufficient durability and impact resistance to the film, and 3 to 10 μm. Is particularly preferred.
Further, the strength of the hard coat layer is preferably 2H or more, more preferably 3H or more, and further preferably 4H or more in the pencil hardness test.
In particular, in the Taber test according to JIS K5400, the smaller the wear amount of the test piece before and after the test, the better.

The hard coat layer is preferably formed by a crosslinking reaction or a polymerization reaction of an ionizing radiation curable compound. For example, a coating composition containing an ionizing radiation-curable polyfunctional monomer or polyfunctional oligomer is applied on a transparent substrate film, and the polyfunctional monomer or polyfunctional oligomer is formed by a crosslinking reaction or a polymerization reaction. Can do.
The functional group of the ionizing radiation-curable polyfunctional monomer or polyfunctional oligomer is preferably a light, electron beam, or radiation polymerizable group, and among them, a photopolymerizable functional group is preferable.
Examples of the photopolymerizable functional group include unsaturated polymerizable functional groups such as a (meth) acryloyl group, a vinyl group, a styryl group, and an allyl group. Among them, a (meth) acryloyl group is preferable.

Further, instead of or in addition to the monomer having a polymerizable unsaturated group, a crosslinkable functional group may be introduced into the binder.
Examples of the crosslinkable functional group include isocyanate group, epoxy group, aziridine group, oxazoline group, aldehyde group, carbonyl group, hydrazine group, carboxyl group, methylol group and active methylene group.
Further, vinylsulfonic acid, acid anhydride, cyanoacrylate derivative, melamine, etherified methylol, ester and urethane, and metal alkoxide such as tetramethoxysilane can also be used as a monomer having a crosslinked structure.
A functional group that exhibits crosslinkability as a result of the decomposition reaction, such as a blocked isocyanate group, may be used.
That is, in the present invention, the crosslinkable functional group may not be immediately reactive but may be reactive as a result of decomposition.
These binders having a crosslinkable functional group can form a crosslinked structure by heating after coating.

  The hard coat layer contains matte particles having an average particle size of 1.0 to 10.0 μm, preferably 1.5 to 7.0 μm, such as inorganic compound particles or resin particles, for the purpose of imparting internal scattering properties. May be.

For the purpose of controlling the refractive index of the hard coat layer, a high refractive index monomer, inorganic particles, or both can be added to the binder of the hard coat layer. In addition to the effect of controlling the refractive index, the inorganic particles also have the effect of suppressing cure shrinkage due to the crosslinking reaction.
In the present invention, a polymer formed by polymerizing the polyfunctional monomer and / or the high refractive index monomer after the formation of the hard coat layer, and the inorganic particles dispersed therein are referred to as a binder.

The haze of the hard coat layer varies depending on the function imparted to the antireflection film.
When maintaining the sharpness of the image, suppressing the reflectance of the surface, and not imparting the light scattering function inside and on the surface of the hard coat layer, the haze value is preferably as low as possible, specifically 10% or less is preferable, 5% or less is more preferable, and 2% or less is still more preferable.

On the other hand, in addition to the function of suppressing the reflectance of the surface, in the case of imparting an antiglare function by surface scattering of the hard coat layer, the surface haze is preferably 5 to 15%, and preferably 5 to 10%. It is more preferable.
Also, when it is difficult to see the pattern, color unevenness, brightness unevenness, glare, etc. of the liquid crystal panel due to internal scattering of the hard coat layer, or to add the function of expanding the viewing angle by scattering, the internal haze value (from the total haze value) The value obtained by subtracting the surface haze value) is preferably 10 to 90%, more preferably 15 to 70%, and still more preferably 20 to 50%.
The film of the present invention can freely set surface haze and internal haze according to the purpose.

In addition, for the surface irregularity shape of the hard coat layer, in order to obtain a clear surface for the purpose of maintaining the sharpness of the image, among the characteristics indicating the surface roughness, for example, the centerline average roughness (Ra) is set. The thickness is preferably 0.10 μm or less, more preferably 0.09 μm or less, and still more preferably 0.08 μm or less.
In the film of the present invention, the surface unevenness of the hard coat layer is dominant in the surface unevenness of the film, and the center line average roughness of the antireflection film is adjusted by adjusting the center line average roughness of the hard coat layer. It can be set as the said range.

In order to maintain the sharpness of the image, it is preferable to adjust the clarity of the transmitted image in addition to adjusting the uneven shape of the surface. The clearness of the transmitted image of the clear antireflection film is preferably 60% or more.
The transmitted image clarity is generally an index indicating the degree of blurring of an image reflected through a film, and the larger this value, the clearer and better the image viewed through the film. The transmitted image definition is preferably 70% or more, and more preferably 80% or more.

[Surface improver]
The coating solution used to make any layer on the base film has at least one of fluorine-based and silicone-based to improve surface defects (coating irregularities, drying irregularities, point defects, etc.) It is preferable to add a surface improver.

The surface improver preferably changes the surface tension of the coating solution by 1 mN / m or more. Here, when the surface tension of the coating liquid changes by 1 mN / m or more, the surface tension of the coating liquid after the addition of the surface conditioner is added, including the concentration process during coating / drying. It means that it changes by 1 mN / m or more as compared with the surface tension of the coating liquid that has not been applied.
The surface improver is preferably a surface improver that has an effect of lowering the surface tension of the coating solution by 1 mN / m or more, more preferably a surface improver that lowers by 2 mN / m or more, and 3 mN / m. It is more preferable that the surface conditioner be lowered.

  Preferable examples of the fluorine-based surface improver include compounds containing a fluoroaliphatic group. Examples of preferred compounds include those described in JP-A-2005-115359, JP-A-2005-221963, and JP-A-2005-234476.

When the protective film for a polarizing plate of the present invention is used on the surface of a liquid crystal display device, a reflection image of a surrounding object may be reflected on the surface, which may reduce the visibility of the display image. It is preferable that the surface of the hard coat layer is provided with unevenness to impart the ability to scatter light on the surface (antiglare property).
The first coating layer of the present invention may have a refractive index higher than that of the base film, and interference unevenness occurs due to the refractive index difference between the coating layer and the base film. In order to prevent the deterioration of visibility due to this interference unevenness, it is preferable to impart light scattering properties.
The hard coat layer is preferably a light-scattering layer having light scattering properties on the surface and / or inside (when the surface is given scattering properties, it may be referred to as an antiglare layer).

<< Anti-glare layer >>
The antiglare layer is formed for the purpose of contributing to the film antiglare properties due to surface scattering and preferably hard coat properties for improving the scratch resistance of the film. Therefore, in this invention, it can be used as one embodiment of a hard-coat layer.

As a method of forming the antiglare property, a method of laminating and forming a mat-shaped shaping film having fine irregularities on the surface as described in JP-A-6-16851, JP-A-2000-206317 As described, a method of forming by curing shrinkage of an ionizing radiation curable resin due to a difference in ionizing radiation dose, a good solvent for a translucent resin by drying as described in JP 2000-338310 A A method of forming concavo-convex on the surface of the coating film by solidifying the light-transmitting fine particles and the light-transmitting resin by gelation by reducing the mass ratio of the resin, as described in JP 2000-275404 A A method of imparting surface irregularities by the pressure from the phase, phase separation in the process of evaporation of the solvent from a mixed solution of a plurality of polymers as described in JP-A-2005-195919 Are known a method of forming surface irregularities by utilizing can utilize these known methods.
One preferable form of the antiglare layer that can be used in the present invention contains a binder capable of imparting hard coat properties, translucent particles for imparting antiglare properties, and a solvent as essential components, Surface irregularities are formed by protrusions of the light particles themselves or protrusions formed by an aggregate of a plurality of particles.
The antiglare layer having antiglare properties preferably has both antiglare properties and hard coat properties.

[binder]
Details of the binder and translucent particles will be described below.
The film of the present invention can be formed by a crosslinking reaction or a polymerization reaction of an ionizing radiation curable compound. That is, it is formed by applying a coating composition containing an ionizing radiation-curable polyfunctional monomer or polyfunctional oligomer as a binder on a transparent substrate film, and causing the polyfunctional monomer or polyfunctional oligomer to undergo a crosslinking reaction or a polymerization reaction. can do.
The functional group of the ionizing radiation-curable polyfunctional monomer or polyfunctional oligomer is preferably a light, electron beam, or radiation polymerizable group, and among them, a photopolymerizable functional group is preferable.
Examples of the photopolymerizable functional group include unsaturated polymerizable functional groups such as a (meth) acryloyl group, a vinyl group, a styryl group, and an allyl group. Among them, a (meth) acryloyl group is preferable.

As a specific example of a photopolymerizable polyfunctional monomer having a photopolymerizable functional group,
(Meth) acrylic acid diesters of alkylene glycol such as neopentyl glycol acrylate, 1,6-hexanediol (meth) acrylate, propylene glycol di (meth) acrylate;
(Meth) acrylic acid diesters of polyoxyalkylene glycols such as triethylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate;
(Meth) acrylic acid diesters of polyhydric alcohols such as pentaerythritol di (meth) acrylate;
(Meth) acrylic acid diesters of ethylene oxide or propylene oxide adducts such as 2,2-bis {4- (acryloxy · diethoxy) phenyl} propane and 2-bis {4- (acryloxy · polypropoxy) phenyl} propane ;
Etc.

  Furthermore, epoxy (meth) acrylates, urethane (meth) acrylates, and polyester (meth) acrylates are also preferably used as the photopolymerizable polyfunctional monomer.

Among the above, esters of polyhydric alcohol and (meth) acrylic acid are preferable, and polyfunctional monomers having three or more (meth) acryloyl groups in one molecule are more preferable.
Specifically, trimethylolpropane tri (meth) acrylate, trimethylolethane tri (meth) acrylate, 1,2,4-cyclohexanetetra (meth) acrylate, pentaglycerol triacrylate, pentaerythritol tetra (meth) acrylate, penta Erythritol tri (meth) acrylate, (di) pentaerythritol triacrylate, (di) pentaerythritol pentaacrylate, (di) pentaerythritol tetra (meth) acrylate, (di) pentaerythritol hexa (meth) acrylate, tripentaerythritol triacrylate , Tripentaerythritol hexatriacrylate and the like.
In the present specification, “(meth) acrylate”, “(meth) acrylic acid”, and “(meth) acryloyl” represent “acrylate or methacrylate”, “acrylic acid or methacrylic acid”, and “acryloyl or methacryloyl”, respectively. .

As the monomer binder, monomers having different refractive indexes can be used to control the refractive index of each layer. Examples of particularly high refractive index monomers include bis (4-methacryloylthiophenyl) sulfide, vinyl naphthalene, vinyl phenyl sulfide, 4-methacryloxyphenyl-4′-methoxyphenyl thioether, and the like.
Further, for example, dendrimers described in JP-A-2005-76005 and JP-A-2005-36105, and norbornene ring-containing monomers as described in JP-A-2005-60425 can also be used.

Two or more polyfunctional monomers may be used in combination.
Polymerization of the monomer having an ethylenically unsaturated group can be performed by irradiation with ionizing radiation or heating in the presence of a photo radical initiator or a thermal radical initiator.
It is preferable to use a photopolymerization initiator for the polymerization reaction of the photopolymerizable polyfunctional monomer. As the photopolymerization initiator, a photoradical polymerization initiator and a photocationic polymerization initiator are preferable, and a photoradical polymerization initiator is particularly preferable.

[Photopolymerization initiator]
Examples of photo radical polymerization initiators include acetophenones, benzoins, benzophenones, phosphine oxides, ketals, anthraquinones, thioxanthones, azo compounds, peroxides (JP-A No. 2001-139663, etc.), 2, 3 -Dialkyldione compounds, disulfide compounds, fluoroamine compounds, aromatic sulfoniums, lophine dimers, onium salts, borate salts, active esters, active halogens, inorganic complexes, coumarins and the like.
Examples of acetophenones include 2,2-dimethoxyacetophenone, 2,2-diethoxyacetophenone, p-dimethylacetophenone, 1-hydroxy-dimethylphenylketone, 1-hydroxy-dimethyl-p-isopropylphenylketone, 1-hydroxy Cyclohexyl phenyl ketone, 2-methyl-4-methylthio-2-morpholinopropiophenone, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone, 4-phenoxydichloroacetophenone, 4-t- Butyl-dichloroacetophenone is included.

Examples of benzoins include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzyl dimethyl ketal, benzoin benzene sulfonate, benzoin toluene sulfonate, benzoin methyl ether, benzoin ethyl ether and benzoin isopropyl ether. It is.
Examples of benzophenones include benzophenone, hydroxybenzophenone, 4-benzoyl-4'-methyldiphenyl sulfide, 2,4-dichlorobenzophenone, 4,4-dichlorobenzophenone and p-chlorobenzophenone, 4,4'-dimethylaminobenzophenone (Michler's ketone), 3,3 ′, 4,4′-tetra (t-butylperoxycarbonyl) benzophenone and the like are included.

Examples of the borate salt are described in Japanese Patent Nos. 2764769 and 2002-116539, and in Kunz, Martin “Rad Tech'98. Proceeding April 19-22, 1998, Chicago”. And the organic borate compounds described. For example, the compounds described in JP-A-2002-116539, paragraph numbers [0022] to [0027] can be mentioned.
Examples of other organic boron compounds include JP-A-6-348011, JP-A-7-128785, JP-A-7-140589, JP-A-7-306527, JP-A-7-292014, and the like. Specific examples include organoboron transition metal coordination complexes, and specific examples include ion complexes with cationic dyes.

Examples of phosphine oxides include 2,4,6-trimethylbenzoyldiphenylphosphine oxide.
Examples of the active esters include 1,2-octanedione, 1- [4- (phenylthio)-, 2- (O-benzoyloxime)], sulfonic acid esters, cyclic active ester compounds, and the like.
Specifically, compounds 1 to 21 described in Examples of JP 2000-80068 A are particularly preferable.
Examples of onium salts include aromatic diazonium salts, aromatic iodonium salts, and aromatic sulfonium salts.

Specific examples of the active halogens include Wakabayashi et al., “Bull Chem. Soc Japan”, 42, 2924 (1969), US Pat. No. 3,905,815, JP-A-5-27830, M.M. P. Examples include compounds described in Hutt “Journal of Heterocyclic Chemistry”, Vol. 1 (No. 3), (1970), and in particular, oxazole compounds substituted with a trihalomethyl group: s-triazine compounds.
More preferable examples include s-triazine derivatives in which at least one mono, di, or trihalogen-substituted methyl group is bonded to the s-triazine ring.
Specific examples include S-triazine and oxathiazole compounds, such as 2- (p-methoxyphenyl) -4,6-bis (trichloromethyl) -s-triazine, 2- (p-methoxyphenyl). ) -4,6-bis (trichloromethyl) -s-triazine, 2- (p-styrylphenyl) -4,6-bis (trichloromethyl) -s-triazine, 2- (3-Br-4-di ( Ethyl acetate) amino) phenyl) -4,6-bis (trichloromethyl) -s-triazine, 2-trihalomethyl-5- (p-methoxyphenyl) -1,3,4-oxadiazole.
More specifically, Nos. Described in JP-A-58-15503, p14 to p30, JP-A-55-77742, p6-p10, and JP-B-60-27673, p287. 1-No. 8, p443-p444 No. of JP-A-60-239736. 1-No. 17, No. 4,701,399. Compounds such as 1-19 are particularly preferred.
Examples of inorganic complexes include bis (η ⁵ -2,4-cyclopentadien-1-yl) -bis (2,6-difluoro-3- (1H-pyrrol-1-yl) -phenyl) titanium.
Moreover, 3-ketocoumarin is mentioned as an example of coumarins.

These initiators may be used alone or in combination.
“Latest UV Curing Technology”, Technical Information Association, 1991, p. 159, and “UV curing system” written by Kayo Kiyomi, 1989, General Technology Center, p. Various examples are also described in 65-148 and are useful in the present invention.

  Commercially available photo radical polymerization initiators include KAYACURE (DETX-S, BP-100, BDKM, CTX, BMS, 2-EAQ, ABQ, CPTX, EPD, ITX, QTX, BTC, manufactured by Nippon Kayaku Co., Ltd. MCA, etc.), Irgacure (651, 184, 500, 819, 907, 369, 1173, 1870, 2959, 4265, 4263, etc.) manufactured by Ciba Specialty Chemicals, Ltd., Esacure (KIP100F, KB1, manufactured by Sartomer) EB3, BP, X33, KT046, KT37, KIP150, TZT) and the like and combinations thereof are preferable examples.

  It is preferable to use a photoinitiator in the range of 0.1-15 mass parts with respect to 100 mass parts of polyfunctional monomers, and it is more preferable to use it in the range of 1-10 mass parts.

[Photosensitizer]
In addition to the photopolymerization initiator, a photosensitizer may be used. Specific examples of the photosensitizer include n-butylamine, triethylamine, tri-n-butylphosphine, Michler's ketone and thioxanthone.
Further, one or more auxiliary agents such as an azide compound, a thiourea compound, and a mercapto compound may be used in combination.
Examples of commercially available photosensitizers include KAYACURE (DMBI, EPA) manufactured by Nippon Kayaku Co., Ltd.

[Thermal initiator]
As the thermal radical initiator, organic or inorganic peroxides, organic azo, diazo compounds, and the like can be used.
Specifically, benzoyl peroxide, halogen benzoyl peroxide, lauroyl peroxide, acetyl peroxide, dibutyl peroxide, cumene hydroperoxide, butyl hydroperoxide as organic peroxides, hydrogen peroxide, peroxides as inorganic peroxides. Diazo compounds such as 2,2′-azobis (isobutyronitrile), 2,2′-azobis (propionitrile), 1,1′-azobis (cyclohexanecarbonitrile) as azo compounds such as ammonium sulfate and potassium persulfate And diazoaminobenzene, p-nitrobenzenediazonium and the like.

[Translucent particles]
The translucent particles may be organic particles or inorganic particles. As the translucent particles, plastic beads are preferable, and those having particularly high transparency and a refractive index difference from the binder of 0.01 to 0.3 are preferable.
As organic particles, polymethyl methacrylate particles (refractive index 1.49), crosslinked poly (acryl-styrene) copolymer particles (refractive index 1.54), melamine resin particles (refractive index 1.57), polycarbonate particles ( Refractive index 1.57), polystyrene particles (refractive index 1.60), crosslinked polystyrene particles (refractive index 1.61), polyvinyl chloride particles (refractive index 1.60), benzoguanamine-melamine formaldehyde particles (refractive index 1. 68) etc. are used.
Examples of the inorganic particles include silica particles (refractive index: 1.44), alumina particles (refractive index: 1.63), zirconia particles, titania particles, and inorganic particles having hollows and pores.

  Among the translucent particles, cross-linked polystyrene particles, cross-linked poly ((meth) acrylate) particles, and cross-linked poly (acryl-styrene) particles are preferably used, and each of the translucent particles selected from these particles is used. By adjusting the refractive index of the binder in accordance with the refractive index, the internal haze, surface haze, and centerline average roughness of the present invention can be achieved.

  The refractive index of the binder (translucent resin) and the translucent particles in the present invention is preferably 1.45 to 1.70, and more preferably 1.48 to 1.65. In order to make the refractive index within the above range, the type and amount ratio of the binder and translucent particles may be appropriately selected. How to select can be easily known experimentally in advance.

  Here, the refractive index of the binder can be quantitatively evaluated by directly measuring it with an Abbe refractometer or by measuring a spectral reflection spectrum or a spectral ellipsometry. The refractive index of the translucent particles is measured by measuring the turbidity by dispersing an equal amount of the translucent particles in the solvent in which the refractive index is changed by changing the mixing ratio of two types of solvents having different refractive indexes. It is measured by measuring the refractive index of the solvent when the turbidity is minimized with an Abbe refractometer.

  In the case of the above translucent particles, the translucent particles easily settle in the binder, and therefore an inorganic filler such as silica may be added to prevent sedimentation. As the amount of the inorganic filler added increases, it is more effective in preventing the translucent particles from settling, but adversely affects the transparency of the coating film. Therefore, it is preferable to contain an inorganic filler having a particle size of 0.5 μm or less in an amount of less than 0.1% by mass so as not to impair the transparency of the coating film with respect to the binder.

  The average particle diameter of the translucent particles is preferably 0.5 to 10 μm, and more preferably 2.0 to 8.0 μm. An average particle size of 0.5 μm or more and 10 μm or less is preferable because it does not cause display character blur and does not cause problems such as curling and cost increase.

  Moreover, you may use together and use 2 or more types of translucent particle | grains from which a particle diameter differs. It is possible to impart an antiglare property with a light-transmitting particle having a larger particle diameter, and to reduce the surface roughness with a light-transmitting particle having a smaller particle diameter.

  The translucent particles are preferably blended so as to be contained in an amount of 3-30% by mass in the total solid content of the additive layer, and are formulated so as to be contained in an amount of 5-20% by mass in the total solid content of the additive layer. More preferably. If it is less than 3% by mass, the effect of addition is insufficient, and if it exceeds 30% by mass, problems such as image blur, surface turbidity and glare occur.

The density of the translucent particles is preferably ^{10~1,000mg / m 2, 100~700mg / m} 2 is more preferable.

-Preparation of light-transmitting particles and classification method-
Examples of the method for producing translucent particles in the present invention include suspension polymerization method, emulsion polymerization method, soap-free emulsion polymerization method, dispersion polymerization method, seed polymerization method and the like, and any method may be used. .
These production methods are described, for example, in “Experimental Methods for Polymer Synthesis” (Takayuki Otsu and Masaaki Kinoshita, Chemical Dojinsha), pages 130 and 146 to 147, “Synthetic Polymers”, Vol. 1, p. 246-290, 3rd volume, p. 1 to 108, etc., and Japanese Patent Nos. 2543503, 3508304, 2746275, 3521560, 3580320, and Japanese Patent Laid-Open No. 10-1561. Reference can be made to methods described in JP-A No. 7-2908, JP-A No. 5-297506, JP-A No. 2002-145919, and the like.

The particle size distribution of the translucent particles is preferably monodisperse particles in view of haze value and diffusibility control, and uniformity of the coated surface. For example, when a particle having a particle size of 20% or more than the average particle size is defined as a coarse particle, the ratio of the coarse particle is preferably 1% or less of the total number of particles, and preferably 0.1% or less. More preferred is 0.01% or less.
Particles having such a particle size distribution are also effective means of classification after the preparation or synthesis reaction, and particles having a preferable distribution can be obtained by increasing the number of classifications or increasing the degree of classification. .
It is preferable to use a method such as an air classification method, a centrifugal classification method, a sedimentation classification method, a filtration classification method, or an electrostatic classification method for classification.

Two or more kinds of mat particles having different particle diameters may be used in combination. It is possible to impart anti-glare properties with mat particles having a larger particle size and to impart other optical characteristics with mat particles having a smaller particle size. For example, when an anti-glare antireflection film is attached to a high-definition display of 133 ppi or higher, a problem in display image quality called “glare” may occur.
“Glitter” is derived from the fact that pixels are enlarged or reduced due to irregularities present on the surface of the antiglare and antireflection film, resulting in loss of luminance uniformity. Thus, it can be greatly improved by using mat particles having a refractive index different from that of the binder.
The particle size distribution of the mat particles is measured by a Coulter counter method, and the measured distribution is converted into a particle number distribution.

[Phase separation]
As an example of a method for creating a light scattering layer, a method for creating a light scattering layer by spinodal decomposition of a plurality of polymers can be given as an example of a method other than the use of translucent particles to exhibit antiglare properties. In particular, it is possible to impart good light scattering properties by giving a difference in the refractive indexes of the phase separated phases.
The light scattering layer formed by spinodal decomposition is composed of a plurality of polymers having different refractive indexes, and is usually a phase having at least a co-continuous phase structure in an operating atmosphere (especially at room temperature of about 10 to 30 ° C.). A separation structure is formed.
The co-continuous phase structure is formed by spinodal decomposition from a liquid phase containing a plurality of polymers (liquid phase at room temperature, for example, a mixed liquid or a solution).
The bicontinuous phase structure is usually formed by spinodal decomposition through evaporation of a solvent using a composition (for example, a mixed solution or a solution) containing a plurality of polymers and forming a liquid phase at room temperature.
Since such a light scattering layer is formed from a liquid phase, it has a uniform and fine co-continuous phase structure. When such a protective film for a polarizing plate is used, incident light is substantially isotropically scattered, and directivity can be imparted to transmitted scattered light. Therefore, both high light scattering and directivity can be achieved.

  In order to enhance light scattering properties, a plurality of polymers can be used in combination so that the difference in refractive index is, for example, about 0.01 to 0.2, and preferably about 0.1 to 0.15. If the difference in refractive index is less than 0.01, the intensity of the transmitted scattered light decreases, and if the difference in refractive index is greater than 0.2, high directivity cannot be imparted to the transmitted scattered light.

  The plurality of polymers include, for example, styrene resins, (meth) acrylic resins, vinyl ester resins, vinyl ether resins, halogen-containing resins, olefin resins (including alicyclic olefin resins), polycarbonate resins, and polyesters. Resin, polyamide resin, thermoplastic polyurethane resin, polysulfone resin (polyethersulfone, polysulfone, etc.), polyphenylene ether resin (2,6-xylenol polymer, etc.), cellulose derivatives (cellulose esters, cellulose carbamates) , Cellulose ethers, etc.), silicone resins (polydimethylsiloxane, polymethylphenylsiloxane, etc.), rubbers or elastomers (diene rubbers such as polybutadiene, polyisoprene, styrene-butadiene copolymers, Acrylonitrile - butadiene copolymer, acrylic rubber, urethane rubber, silicone rubber, etc.) can be chosen a suitable combination and the like.

Preferred polymers include, for example, styrene resins, (meth) acrylic resins, vinyl ester resins, vinyl ether resins, halogen-containing resins, alicyclic olefin resins, polycarbonate resins, polyester resins, polyamide resins, Cellulose derivatives, silicone resins, rubbers or elastomers are included.
As the plurality of polymers, a resin that is non-crystalline and is soluble in an organic solvent (in particular, a common solvent capable of dissolving the plurality of polymers) is usually used.
In particular, resins with high moldability or film formability, transparency and weather resistance, such as styrene resins, (meth) acrylic resins, alicyclic olefin resins, polyester resins, cellulose derivatives (cellulose esters, etc.) Etc. are preferable.

  These multiple polymers can be used in appropriate combinations. For example, in a combination of polymers, at least one polymer may be converted to a cellulose derivative, particularly a cellulose ester (eg, cellulose C2-4 alkylcarboxyl such as cellulose diacetate, cellulose triacetate, cellulose acetate propionate, cellulose acetate butyrate, etc. Acid esters) and may be combined with other polymers.

The glass transition temperature of the polymer is, for example, preferably from −100 ° C. to 250 ° C., more preferably from −50 to 230 ° C., and still more preferably from about 0 to 200 ° C. (for example, from about 50 to 180 ° C.).
In view of the strength and rigidity of the sheet, the glass transition temperature of at least one of the constituent polymers is preferably 50 ° C. or higher (for example, about 70 to 200 ° C.), and 100 ° C. or higher (for example, 100 to 170 ° C.). Degree) is more preferable.
The mass average molecular weight of the polymer is, for example, preferably 1,000,000 or less (about 10,000 to 1,000,000), and more preferably in the range of about 10,000 to 700,000.

In the present invention, a wet method is employed in which a solvent is evaporated from a liquid phase containing a plurality of polymers and spinodal decomposition is performed. A light scattering layer having a co-continuous phase structure can be formed.
For this reason, it may be configured by combining a plurality of mutually compatible polymers. However, in order to easily control the phase separation structure by spinodal decomposition and to form a co-continuous phase structure efficiently, incompatible (phase separation) In many cases, a plurality of polymers are combined.

The plurality of polymers can be constituted by a combination of the first polymer and the second polymer, and each of the first polymer and the second polymer may be constituted by a single resin or a plurality of resins. Also good. The combination of the first polymer and the second polymer is not particularly limited.
For example, when the first polymer is a cellulose derivative (for example, cellulose esters such as cellulose acetate propionate), the second polymer is a styrene resin (polystyrene, styrene-acrylonitrile copolymer, etc.), (meta ) Acrylic resins (such as polymethyl methacrylate), alicyclic olefin resins (such as polymers using norbornene as monomers), polycarbonate resins, polyester resins (such as poly C2-4 alkylene arylate copolyester) Or the like.

The ratio of the first polymer to the second polymer is, for example, preferably the former / the latter = about 10/90 to 90/10 (mass ratio), and more preferably about 20/80 to 80/20 (mass ratio). 30/70 to 70/30 (mass ratio) is more preferable, and about 40/60 to 60/40 (mass ratio) is particularly preferable. When the ratio of one polymer is too large, the volume ratio between the separated phases is biased, so that the intensity of scattered light decreases.
In addition, when forming a sheet | seat with a 3 or more some polymer, content of each polymer is 1-90 mass% normally (for example, 1-70 mass%, Preferably 5-70 mass%, More preferably, it is 10 Can be selected from a range of about 70 mass%.

The light scattering layer constituting the protective film for polarizing plate of the present invention has at least a co-continuous phase structure. The co-continuous phase structure is sometimes referred to as a co-continuous structure or a three-dimensional continuous or connected structure, and means a structure in which at least two constituent polymer phases are continuous (for example, a network structure). .
The light scattering layer only needs to have at least a co-continuous phase structure, and may have a structure in which a co-continuous phase structure and a droplet phase structure (independent or isolated phase structure) are mixed.
In spinodal decomposition, a co-continuous phase structure is formed with the progress of phase separation, and when the phase separation is further advanced, the continuous phase becomes discontinuous by its surface tension, resulting in a droplet phase structure (spherical, true spherical) Sea island structure of independent phases).
Therefore, depending on the degree of phase separation, an intermediate structure between the co-continuous phase structure and the droplet phase structure, that is, a phase structure in the process of shifting from the co-continuous phase to the droplet phase can be formed.
In the present invention, the intermediate structure is also referred to as a co-continuous phase structure.
In addition, when the phase separation structure is a mixed structure of a co-continuous phase structure and a droplet structure, the ratio of the droplet phase (independent polymer phase) is preferably 30% or less (volume ratio), for example, and 10% or less (volume ratio). (Volume ratio) is more preferable. The shape of the co-continuous phase structure is not particularly limited, and may be a network shape, particularly a random network shape.

  The bicontinuous phase structure is generally isotropic with reduced anisotropy in the layer or sheet plane. Note that isotropic means that the average interphase distance of the co-continuous phase structure is substantially equal in any direction in the sheet plane.

The bicontinuous phase structure usually has regularity in the interphase distance (distance between the same phases). For this reason, the light scattered on the sheet is directed to a specific direction by Bragg reflection.
Therefore, even when mounted on a reflective liquid crystal display device, the transmitted scattered light can be directed in a certain direction, the display screen can be made highly bright, and the conventional particle dispersion type transmissive polarizing plate can be used. Problems that cannot be solved by the protective film, that is, reflection of a light source (for example, a fluorescent lamp) on the panel can be avoided.

  In the protective film for polarizing plate, the average interphase distance of the co-continuous phase is preferably, for example, 0.5 to 20 μm (for example, 1 to 20 μm), and more preferably about 1 to 15 μm (for example, 1 to 10 μm). If the average interphase distance is too small, it is difficult to obtain high scattered light intensity, and if the average interphase distance is too large, the directivity of transmitted scattered light decreases.

The average interphase distance of the co-continuous layer can be calculated from a photomicrograph (transmission microscope, phase contrast microscope, confocal laser microscope, etc.) of the light scattering layer or the protective film for polarizing plate.
In addition, the scattering angle θ at which the scattered light intensity is maximized is measured by a method similar to the scattered light directivity evaluation method described later, and the average interphase distance d of the co-continuous phase is calculated from the following Bragg reflection condition equation. May be.

2d · sin (θ / 2) = λ
(Where d is the average interphase distance of co-continuous phases, θ is the scattering angle, and λ is the wavelength of light)

[Emboss]
An example of a method for creating a light scattering layer is a method for creating a light scattering layer by an embossing method as an example of a method other than the use of translucent particles to exhibit antiglare properties.
The light scattering layer prepared by the embossing method is an ionizing radiation curable resin composition or a thermosetting resin composition formed on a transparent substrate with a mat-shaped molding film having fine irregularities on the surface. A light diffusion layer consisting essentially of is formed.
When the resin is an ionizing radiation curable resin composition, the light scattering layer is produced by coating the ionizing radiation curable resin composition on a transparent substrate and then applying the ionizing radiation curable resin. By laminating a mat-shaped shaped film having fine irregularities on the surface of the uncured coating film of the composition, and then irradiating ionizing radiation on the coated film on which the shaped film is laminated, It is preferable to manufacture the coating film of the ionizing radiation curable resin composition by a manufacturing method in which the shaped film is peeled from the cured coating film of the ionizing radiation curable resin.
When the resin is a thermosetting resin composition, the thermosetting resin composition is applied on a transparent substrate, and then the uncured coating film of the applied thermosetting resin composition is applied. A mat-like shaped film having fine irregularities on the surface is laminated, and then the coating film laminated with the shaped film is heated and cured, and then the cured thermosetting resin composition is applied. It is preferable to manufacture by the manufacturing method which peels a shaping film from a film | membrane.

When laminating the shaping film on the coating film of the uncured ionizing radiation curable resin composition, if the coated resin is of a solvent dilution type, the solvent is dried and then laminating, If the applied resin is solventless, lamination is performed as it is.
The film forming component of the ionizing radiation curable resin composition used for the light diffusion layer of the embossing method preferably has an acrylate functional group.
For example, relatively low molecular weight polyester resins, polyether resins, acrylic resins, epoxy resins, urethane resins, alkyd resins, spiroacetal resins, polybutadiene resins, polythiol polyene resins, (meth) acrylates of polyfunctional compounds such as polyhydric alcohols Monofunctional monomers such as ethyl (meth) acrylate, ethylhexyl (meth) acrylate, styrene, methylstyrene, N-vinyl pyrrolidone, and polyfunctional monomers such as trimethylolpropane tri ( (Meth) acrylate, hexanediol (meth) acrylate, tripropylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, pentaerythritol tri (meth) acrylate DOO, dipentaerythritol hexa (meth) acrylate, 1,6-hexanediol di (meth) acrylate, those of relatively high content of neopentyl glycol di (meth) acrylate can be used.

  The film forming component is particularly preferably a mixture of polyester acrylate and polyurethane acrylate. The reason is that polyester acrylate is very hard and suitable for obtaining a hard coat, but polyester acrylate alone has low impact and is brittle. Therefore, polyurethane acrylate is used in combination to impart impact resistance and flexibility to the coating film. At this time, the blending ratio of the polyurethane acrylate with respect to 100 parts by mass of the polyester acrylate is 30 parts by mass or less. If this value is exceeded, the coating film is too soft and the hardness is lost.

Furthermore, in order to make the ionizing radiation curable resin composition into an ultraviolet curable resin composition, acetophenones, benzophenones, Michler benzoylbenzoate, α-amyloxime ester, tetra Methyl thiuram monosulfide, thioxanthones, and n-butylamine, triethylamine, tri-n-butylphosphine, and the like can be used as a photosensitizer.
Particularly in the present invention, it is preferable to mix urethane acrylate as an oligomer and dipentaerythritol hexa (meth) acrylate as a monomer.

The paint for forming a light-diffusing and hard coat (scratch-resistant) coating film contains 10 parts by mass or more and 100 parts by mass or less of solvent-drying resin with respect to 100 parts by mass of ionizing radiation curable resin Also good.
As the solvent-drying resin, a thermoplastic resin is mainly used. The types of solvent-drying thermoplastic resins added to ionizing radiation curable resins are usually those used, especially when a mixture of polyester acrylate and polyurethane acrylate is used for ionizing radiation curable resins. In the solvent-drying resin, polymethyl methacrylate acrylate or polybutyl methacrylate acrylate can keep the hardness of the coating film high.
In addition, in this case, since the refractive index is close to that of the main ionizing radiation curable resin, the transparency of the coating film is not impaired, and it is advantageous in terms of transparency, particularly low haze value, high transmittance, and compatibility. .

  In addition, when using a cellulose-based resin such as triacetylcellulose as the transparent substrate, the solvent-drying resin to be included in the ionizing radiation curable resin includes nitrocellulose, acetylcellulose, cellulose acetate propionate, ethylhydroxyethylcellulose, etc. The cellulosic resin is advantageous in terms of adhesion and transparency of the coating film.

  The film thickness of the antiglare layer is preferably 1 to 25 μm, and more preferably 2 to 15 μm. If it is too thin, the hard property is insufficient, and if it is too thick, curling and brittleness may be deteriorated and workability may be lowered.

Furthermore, when it is difficult to see the pattern, color unevenness, luminance unevenness, glare, etc. of the liquid crystal panel due to internal scattering of the hard coat layer, or to add the function of expanding the viewing angle by scattering, the internal haze value (from the total haze value) The value obtained by subtracting the surface haze value) is preferably 10 to 80%, more preferably 15 to 70%, and still more preferably 20 to 60%.
The film of the present invention can freely set surface haze and internal haze according to the purpose.

  On the other hand, the center line average roughness (Ra) of the antiglare layer is preferably in the range of 0.01 to 0.40 μm, and more preferably in the range of 0.05 to 0.20 μm. If it exceeds 0.40 μm, problems such as glare and whitening of the surface when external light is reflected occur. Further, it is preferable that the value of the transmitted image definition is 5 to 60%.

  The strength of the antiglare layer is preferably 2H or more, more preferably 3H or more, and still more preferably 5H or more in the pencil hardness test.

[Hard coat layer solvent]
Since the hard coat layer of the present invention is often wet-coated on the coating layer, the solvent used in the coating composition is an important factor. The requirements for the solvent include sufficiently dissolving various solutes such as the above-mentioned translucent resin, not dissolving the above-mentioned translucent fine particles, and being difficult to generate coating unevenness and drying unevenness in the coating to drying process. .
In addition, the solubility of the lower layer is not too high (necessary for failure prevention such as deterioration of flatness and whitening), and conversely, the coating layer is dissolved and swollen to the minimum extent (necessary for adhesion). This is a preferable characteristic.
One type of solvent may be used, but it is particularly preferable to adjust the solubility, swelling property, material solubility, drying property, particle cohesiveness, and the like of the coating layer using two or more types of solvents. In addition, by adding a small amount of highly swellable solvent to the main solvent having low swellability of the coating layer, it is possible to improve adhesion with the coating layer without deteriorating other performance and surface condition. it can.
As specific examples, various ketones (such as methyl ethyl ketone, acetone, methyl isobutyl ketone, and cyclohexanone) and various cellosolves (such as ethyl cellosolve, butyl cellosolve, and propylene glycol monomethyl ether) are preferably used as the solvent.
In addition, various alcohols (propylene glycol, ethylene glycol, ethanol, methanol, isopropyl alcohol, 1-butanol, 2-butanol, etc.), toluene and the like are preferably used.

  In the present invention, when the hard coat layer is directly applied on the easy adhesion layer, it is preferable to use a solvent capable of dissolving and swelling the easy adhesion layer. In particular, when the easy adhesion layer is a vinylidene chloride latex, it is preferable to add tetrahydrofuran. It is more preferable to use a vinylidene chloride copolymer for the coating layer so that it can be dissolved in toluene, a ketone solvent, etc., and toluene or a ketone solvent is used without using tetrahydrofuran.

[High refractive index layer (medium refractive index layer)]
On the film of the present invention, when a high refractive index layer and a medium refractive index layer are provided on the hard coat layer and optical interference is used together with the low refractive index layer described later, the antireflection property can be further improved.
In the following description, the high refractive index layer and the medium refractive index layer may be collectively referred to as a high refractive index layer.
In the present invention, “high”, “medium”, and “low” in the high refractive index layer, the middle refractive index layer, and the low refractive index layer represent the relative refractive index relationship between the layers.
In terms of the relationship with the transparent substrate, the refractive index preferably satisfies the relationship of transparent substrate film> low refractive index layer, high refractive index layer> transparent substrate film.
In the present specification, the high refractive index layer, the middle refractive index layer, and the low refractive index layer may be collectively referred to as an antireflection layer.

  In order to construct an antireflection film by constructing a low refractive index layer on a high refractive index layer, the refractive index of the high refractive index layer is preferably 1.55 to 2.40, and 1.60. To 2.20 is more preferable, 1.65 to 2.10 is more preferable, and 1.80 to 2.00 is particularly preferable.

  When the first coating layer, the easy adhesion layer, the hard coat layer, the medium refractive index layer, the high refractive index layer, and the low refractive index layer are coated in the order from the transparent base film, when creating an antireflection film, the high refractive index The refractive index of the refractive index layer is preferably 1.65 to 2.40, more preferably 1.70 to 2.20. The refractive index of the middle refractive index layer is adjusted to be a value between the refractive index of the low refractive index layer and the refractive index of the high refractive index layer. The refractive index of the middle refractive index layer is preferably 1.55-1.80.

Specific examples of the inorganic particles used in the high refractive index layer and the medium refractive index layer include TiO ₂ , ZrO ₂ , Al ₂ O ₃ , In ₂ O ₃ , ZnO, SnO ₂ , Sb ₂ O ₃ , ITO and SiO _2. Etc. Among these, TiO ₂ and ZrO ₂ are particularly preferable in terms of increasing the refractive index.
The inorganic filler is preferably subjected to a silane coupling treatment or a titanium coupling treatment on the surface, and a surface treatment agent having a functional group capable of reacting with a binder species on the filler surface is preferably used.

The content of the inorganic particles in the high refractive index layer is preferably 10 to 90% by mass, more preferably 15 to 80% by mass, and still more preferably 15 to 75% by mass with respect to the mass of the high refractive index layer. Two or more kinds of inorganic particles may be used in combination in the high refractive index layer.
When the low refractive index layer is provided on the high refractive index layer, the refractive index of the high refractive index layer is preferably higher than the refractive index of the transparent substrate film.
The high refractive index layer contains an ionizing radiation curable compound containing an aromatic ring, an ionizing radiation curable compound containing a halogenated element other than fluorine (for example, Br, I, Cl, etc.), and atoms such as S, N, P, etc. A binder obtained by a crosslinking or polymerization reaction such as an ionizing radiation curable compound can also be preferably used.

  The film thickness of the high refractive index layer can be appropriately designed depending on the application. When using a high refractive index layer as an optical interference layer described later, 30 to 200 nm is preferable, 50 to 170 nm is more preferable, and 60 to 150 nm is still more preferable.

  The haze of the high refractive index layer is preferably as low as possible when it does not contain particles that impart an antiglare function. For example, it is preferably 5% or less, more preferably 3% or less, and still more preferably 1% or less. The high refractive index layer is preferably constructed on the transparent substrate film via another layer.

  When the protective film for polarizing plates of the present invention is used on the surface of an image display device, it is also preferable to form a low refractive index layer on the surface of the hard coat layer as a method for preventing reflection. The low refractive index layer that can be preferably used in the present invention will be described below.

[Low refractive index layer]
The low refractive index layer used in the present invention has a thermosetting property and / or a photocuring property mainly comprising a fluorine-containing compound containing a fluorine atom in a range of 35 to 80% by mass and containing a crosslinkable or polymerizable functional group. It is preferably formed by applying a composition having the same.
The refractive index of the low refractive index layer in the antiglare antireflection film of the present invention is preferably 1.45 or less, more preferably 1.30 or more and 1.40 or less, and 1.33 or more and 1.37 or less. Further preferred.
Further, the low refractive index layer preferably satisfies the following formula (2) from the viewpoint of reducing the reflectance.
(M / 4) × 0.7 <n1 × d1 <(m / 4) × 1.3 Expression (2)
In Formula (2), m is a positive odd number, n1 is the refractive index of the low refractive index layer, and d1 is the film thickness (nm) of the low refractive index layer. Further, λ is a wavelength, which is a value in the range of 500 to 550 nm.
In addition, satisfy | filling said Numerical formula (2) means that m (positive odd number, usually 1) which satisfy | fills Numerical formula (2) exists in the said wavelength range.

The low refractive index layer is a cured film formed by, for example, applying, drying and curing a curable composition containing a fluorine-containing compound as a main component.
The curable composition used in forming the low refractive index layer contains at least two of (A) a fluorine-containing compound, (B) inorganic fine particles, and (C) an organosilane compound. Is preferable, and it is particularly preferable that all three types are contained.
As the fluorine-containing compound, it is preferable to use a fluorine-containing polymer having a low refractive index or a fluorine-containing sol-gel material.
The fluorine-containing polymer or fluorine-containing sol-gel is crosslinked by heat or ionizing radiation, the dynamic friction coefficient of the surface of the low refractive index layer formed is 0.03 to 0.30, and the contact angle with water is 85 to 120. A material with a temperature of ° is preferred.

-Fluoropolymer for low refractive index layer-
Next, the material for forming the low refractive index layer will be described below.
The fluoropolymer has a cured film with a coefficient of dynamic friction of 0.03 to 0.20, a contact angle with water of 90 to 120 °, and a sliding angle of pure water of 70 ° or less, and heat or ionization. A polymer that is cross-linked by radiation is preferable from the viewpoint of improving productivity in the case of applying and curing a roll film while conveying the web.
In addition, when the antiglare film or the antiglare antireflection film of the present invention is mounted on an image display device, the lower the peel strength from a commercially available adhesive tape, the easier it is to peel off after sticking a sticker or memo. The force is preferably 500 gf (4.9 N) or less, more preferably 300 gf (2.9 N) or less, and even more preferably 100 gf (0.98 N) or less. Further, the higher the surface hardness measured with a microhardness meter, the harder it is to scratch. Therefore, the surface hardness is preferably 0.3 GPa or more, and more preferably 0.5 GPa or more.

  The fluorine-containing polymer used in the low refractive index layer is preferably a fluorine-containing polymer containing a fluorine atom in a range of 35 to 80% by mass and containing a crosslinkable or polymerizable functional group. In addition to the hydrolyzate or dehydration condensate of an alkyl group-containing silane compound [for example, (heptadecafluoro-1,1,2,2-tetrahydrodecyl) triethoxysilane], a fluorine-containing monomer unit and a crosslinking reactive unit are constituted. Examples thereof include a fluorine-containing copolymer as a unit. In the case of a fluorinated copolymer, the main chain preferably consists of only carbon atoms. That is, it is preferable that the main chain skeleton does not have an oxygen atom or a nitrogen atom.

  Specific examples of the fluorine-containing monomer unit include, for example, fluoroolefins (for example, fluoroethylene, vinylidene fluoride, tetrafluoroethylene, perfluorooctylethylene, hexafluoropropylene, perfluoro-2,2-dimethyl-1,3- Dioxoles, etc.), (meth) acrylic acid partial or fully fluorinated alkyl ester derivatives (for example, Biscoat 6FM (produced by Osaka Organic Chemicals) and M-2020 (produced by Daikin)), fully or partially fluorinated vinyl ethers, etc. However, perfluoroolefins are preferred, and hexafluoropropylene is more preferred from the viewpoints of refractive index, solubility, transparency, availability, and the like.

  Examples of the crosslinking reactive unit include a structural unit obtained by polymerization of a monomer having a self-crosslinking functional group in the molecule such as glycidyl (meth) acrylate and glycidyl vinyl ether; carboxyl group, hydroxy group, amino group, sulfo group A structural unit obtained by polymerization of a monomer having, for example, (meth) acrylic acid, methylol (meth) acrylate, hydroxyalkyl (meth) acrylate, allyl acrylate, hydroxyethyl vinyl ether, hydroxybutyl vinyl ether, maleic acid, crotonic acid, etc. And a structural unit in which a crosslinkable reactive group such as a (meth) acryloyl group is introduced by a polymer reaction (for example, it can be introduced by a technique such as allowing acrylic acid chloride to act on a hydroxy group).

Further, in addition to the fluorine-containing monomer unit and the crosslinking reactive unit, from the viewpoint of solubility in a solvent, film transparency, and the like, a monomer that does not contain a fluorine atom is appropriately copolymerized to introduce another polymerization unit. You can also
There are no particular limitations on the monomer units that can be used in combination. For example, olefins [ethylene, propylene, isoprene, vinyl chloride, vinylidene chloride, etc.], acrylic esters [methyl acrylate, methyl acrylate, ethyl acrylate, acrylic acid 2 -Ethylhexyl], methacrylate esters [methyl methacrylate, ethyl methacrylate, butyl methacrylate, ethylene glycol dimethacrylate, etc.], styrene derivatives [styrene, divinylbenzene, vinyl toluene, α-methylstyrene, etc.], vinyl ethers [methyl Vinyl ether, ethyl vinyl ether, cyclohexyl vinyl ether, etc.], vinyl esters [vinyl acetate, vinyl propionate, vinyl cinnamate, etc.], acrylamides [N-tertbutylacrylamide, N-silane] B hexyl acrylamide, methacrylamides, acrylonitrile derivatives, and the like.

  About the said fluorine-containing polymer, you may use together suitably the hardening | curing agent of Unexamined-Japanese-Patent No. 10-25388 and Unexamined-Japanese-Patent No. 10-147739.

The fluorine-containing polymer particularly useful in the present invention is a random copolymer of perfluoroolefin and vinyl ethers or vinyl esters.
In particular, it preferably has a group capable of undergoing crosslinking reaction alone [radical reactive group such as (meth) acryloyl group, ring-opening polymerizable group such as epoxy group and oxetanyl group].
These cross-linking reactive group-containing polymer units preferably occupy 5 to 70 mol% of the total polymer units of the polymer, and more preferably occupy 30 to 60 mol%.

  A preferred form of the fluorine-containing polymer for the low refractive index layer used in the present invention is a copolymer represented by the following general formula (4).

In general formula (4), L preferably represents a linking group having 1 to 10 carbon atoms, more preferably represents a linking group having 1 to 6 carbon atoms, and still more preferably represents a linking group having 2 to 4 carbon atoms. These may be linear or branched, may have a ring structure, and may have a heteroatom selected from O, N and S.
Examples of L _{^{are, * - (CH 2) 2}} -O- **, * - (CH 2) 2 -NH- **, * - (CH 2) 4 -O- **, * - (CH 2 _{^{) 6 -O- **, * - (}} CH 2) 2 -O- (CH 2) 2 -O- **, * -CONH- (CH 2) 3 -O- **, * -CH 2 CH ( OH) CH ₂ —O— ^** , ^* —CH ₂ CH ₂ OCONH (CH ₂ ) ₃ —O— ^** ( ^* represents a connecting site on the polymer main chain side, and ^** represents a (meth) acryloyl group side. Represents a connecting site). m represents 0 or 1;
Moreover, in General formula (4), X represents a hydrogen atom or a methyl group. From the viewpoint of curing reactivity, a hydrogen atom is preferable.

  In the general formula (4), A represents a repeating unit derived from an arbitrary vinyl monomer, and is not particularly limited as long as it is a constituent component of a monomer copolymerizable with hexafluoropropylene. The polymer Tg (contributes to film hardness), solubility in solvents, transparency, slipperiness, dustproof / antifouling properties, etc., can be selected as appropriate, depending on the purpose. You may be comprised by the monomer.

  Examples of the vinyl monomer include methyl vinyl ether, ethyl vinyl ether, t-butyl vinyl ether, cyclohexyl vinyl ether, isopropyl vinyl ether, hydroxyethyl vinyl ether, hydroxybutyl vinyl ether, glycidyl vinyl ether, allyl vinyl ether and other vinyl ethers, vinyl acetate, propionic acid Vinyl esters such as vinyl and vinyl butyrate, methyl (meth) acrylate, ethyl (meth) acrylate, hydroxyethyl (meth) acrylate, glycidyl methacrylate, allyl (meth) acrylate, (meth) acryloyloxypropyltrimethoxysilane, etc. (Meth) acrylates, styrene, styrene derivatives such as p-hydroxymethylstyrene, crotonic acid, maleic acid While such unsaturated carboxylic acids and derivatives thereof such as itaconic acid, vinyl ether derivatives, is preferably a vinyl ester derivative, and more preferably ether derivative.

x, y, and z represent mol% of each constituent component, and 30 ≦ x ≦ 60, 5 ≦ y ≦ 70, and 0 ≦ z ≦ 65 are preferable, 35 ≦ x ≦ 55, 30 ≦ y ≦ 60, and 0 ≦. z ≦ 20 is more preferable, and 40 ≦ x ≦ 55, 40 ≦ y ≦ 55, and 0 ≦ z ≦ 10 are more preferable. However, x + y + z = 100.
As a particularly preferred form of the copolymer used in the present invention, the following general formula (5) may be mentioned.

In General formula (5), X represents the same meaning as General formula (4), and its preferable range is also the same.
n represents an integer of 2 ≦ n ≦ 10, preferably 2 ≦ n ≦ 6, and particularly preferably 2 ≦ n ≦ 4.
B represents a repeating unit derived from an arbitrary vinyl monomer, and may be composed of a single composition or a plurality of compositions. As an example, what was demonstrated as an example of A in the said General formula (4) is applicable.
x, y, z1, and z2 represent mol% of each repeating unit, and x and y preferably satisfy 30 ≦ x ≦ 60 and 5 ≦ y ≦ 70, respectively, and 35 ≦ x ≦ 55, 30 ≦ y ≦ 60 is more preferable, and 40 ≦ x ≦ 55 and 40 ≦ y ≦ 55 are still more preferable. z1 and z2 preferably satisfy 0 ≦ z1 ≦ 65 and 0 ≦ z2 ≦ 65, more preferably 0 ≦ z1 ≦ 30 and 0 ≦ z2 ≦ 10, and 0 ≦ z1 ≦ 10 and 0 ≦ z2. More preferably, ≦ 5. However, x + y + z1 + z2 = 100.
The copolymer represented by the general formula (4) and the general formula (5) is, for example, a copolymer containing a hexafluoropropylene component and a hydroxyalkyl vinyl ether component (meth) by any of the methods described above. It can be synthesized by introducing an acryloyl group. As the reprecipitation solvent used at this time, isopropanol, hexane, methanol and the like are preferable.
Preferable specific examples of the copolymer represented by the general formula (4) and the general formula (5) include those described in [0035] to [0047] of JP-A-2004-45462. Can be synthesized by the method described in the publication.

-Inorganic fine particles for low refractive index layer-
The amount of the inorganic fine particles is ^{preferably 1mg / m 2 ~100mg / m 2} , more preferably ^{5mg / m 2 ~80mg / m 2} , 10mg / m 2 ~60mg / m 2 is more preferable. If the amount is too small, the effect of improving the scratch resistance is reduced. It is preferable to be inside.
Since the inorganic fine particles are contained in the low refractive index layer, it is desirable to have a low refractive index. Examples thereof include fine particles of magnesium fluoride and silicon oxide (silica). In particular, silica fine particles are preferable in terms of refractive index, dispersion stability, and cost.
The average particle diameter of the inorganic fine particles is, for example, 10% to 100%, preferably 30% to 100%, more preferably 35% to 80%, and more preferably 40% to 60% of the thickness of the low refractive index layer. preferable. That is, when the thickness of the low refractive index layer is 100 nm, the particle size of the silica fine particles is preferably 30 nm to 100 nm, more preferably 35 nm to 80 nm, and further preferably 40 nm to 60 nm.
If the particle size of the inorganic fine particles is too small, the effect of improving the scratch resistance is reduced. Therefore, it is preferable to be within the above range. The inorganic fine particles may be either crystalline or amorphous, and may be monodispersed particles or aggregated particles as long as a predetermined particle size is satisfied. The shape is most preferably a spherical diameter, but there is no problem even if the shape is indefinite.
Here, the average particle diameter of the inorganic fine particles is measured by a Coulter counter.

In order to further reduce the refractive index increase of the low refractive index layer, the inorganic fine particles preferably have a hollow structure, and the refractive index of the inorganic fine particles is preferably 1.17 to 1.40, and 1.17. To 1.35 is more preferable, and 1.17 to 1.30 is more preferable. Here, the refractive index represents the refractive index of the entire particle, and does not represent the refractive index of only the inorganic material of the outer shell in the case of inorganic fine particles having a hollow structure. At this time, when the radius of the cavity in the particle is a and the radius of the particle outer shell is b, the porosity x is expressed by the following formula (3).
^{x = (4πa 3/3)} / (4πb 3/3) × 100 ···· equation (3)
The porosity x is preferably 10 to 60%, more preferably 20 to 60%, and still more preferably 30 to 60%.
If the refractive index of hollow inorganic fine particles is made lower and the porosity is increased, the thickness of the outer shell becomes thinner and the strength of the particles becomes weaker. Therefore, from the viewpoint of scratch resistance, the refractive index is 1 Particles with a low refractive index of less than .17 do not hold.
The refractive index of the inorganic fine particles can be measured with an Abbe refractometer (manufactured by Atago Co., Ltd.).

In addition, at least one kind of inorganic fine particles (hereinafter referred to as “small size inorganic fine particles”) having an average particle size of less than 25% of the thickness of the low refractive index layer is referred to as “inorganic fine particles (hereinafter referred to as“ small size inorganic fine particles ”). It may be used in combination with “large-size inorganic fine particles”.
Since the small-sized inorganic fine particles can be present in the gaps between the large-sized inorganic fine particles, they can contribute as a retaining agent for the large-sized inorganic fine particles.
When the low refractive index layer is 100 nm, the average particle size of the small-sized inorganic fine particles is preferably 1 nm to 20 nm, more preferably 5 nm to 15 nm, and still more preferably 10 nm to 15 nm. Use of such inorganic fine particles is preferable in terms of raw material costs and a retaining agent effect.
As described above, the inorganic fine particles have an average particle size of 30 to 100% of the thickness of the low refractive index layer as described above, have a hollow structure, and have a refractive index of 1.17 to 1. What is 40 is used especially preferably.

Inorganic fine particles are treated with physical surface treatment such as plasma discharge treatment or corona discharge treatment in order to stabilize dispersion in the dispersion or coating solution, or to improve the affinity and binding properties with the binder component. Chemical surface treatment with a surfactant, a coupling agent, or the like may be performed. Of these, the use of a coupling agent is particularly preferred.
As the coupling agent, an alkoxy metal compound (eg, titanium coupling agent, silane coupling agent) is preferably used. Of these, silane coupling treatment is particularly effective.
The coupling agent is used as a surface treatment agent for the inorganic fine particles of the low refractive index layer in advance for surface treatment prior to the preparation of the layer coating solution, and is further added as an additive during the preparation of the layer coating solution. It is preferable to make it contain in a layer.
The inorganic fine particles are preferably dispersed in the medium in advance before the surface treatment in order to reduce the load of the surface treatment.

-Organosilane compound for low refractive index layer-
Next, (C) the organosilane compound will be described.
The curable composition includes an organosilane compound, a hydrolyzate of the organosilane, and a partial condensate of the hydrolyzate of the organosilane (hereinafter, the obtained reaction solution is also referred to as “sol component”). It is preferable to contain at least one selected from the group consisting of scratch resistance, particularly in terms of achieving both antireflection ability and scratch resistance.
These components function as a binder for the low refractive index layer by applying the curable composition and then condensing in a drying and heating process to form a cured product. In the present invention, since the fluorine-containing compound preferably has the fluorine-containing polymer, a binder having a three-dimensional structure is formed by irradiation with actinic rays.
The organosilane compound is preferably represented by the following general formula (6).

In the general formula (6), R ¹⁰ represents a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group. Examples of the alkyl group include methyl, ethyl, propyl, isopropyl, hexyl, decyl, hexadecyl and the like.
As an alkyl group, a C1-C30 thing is preferable, a C1-C16 thing is more preferable, and a C1-C6 thing is still more preferable. Examples of the aryl group include phenyl and naphthyl, and a phenyl group is preferable.
X represents a hydroxyl group or a hydrolyzable group, for example, an alkoxy group (preferably an alkoxy group having 1 to 5 carbon atoms, such as a methoxy group or an ethoxy group), a halogen atom (for example, Cl, Br, I or the like). ) And R ² COO (R ² is preferably a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. Examples include CH ₃ COO, C ₂ H ₅ COO, etc.), and an alkoxy group. It is preferable that it is methoxy group or ethoxy group.
m represents an integer of 1 to 3, preferably 1 or 2, and more preferably 1.

When R ¹⁰ or X there are a plurality, a plurality of R ¹⁰ or X may be different even in the same, respectively.
The substituent contained in R ¹⁰ is not particularly limited, but a halogen atom (fluorine, chlorine, bromine, etc.), a hydroxyl group, a mercapto group, a carboxyl group, an epoxy group, an alkyl group (methyl, ethyl, i-propyl, propyl, t-butyl etc.), aryl groups (phenyl, naphthyl etc.), aromatic heterocyclic groups (furyl, pyrazolyl, pyridyl etc.), alkoxy groups (methoxy, ethoxy, i-propoxy, hexyloxy etc.), aryloxy (phenoxy etc.) ), Alkylthio groups (methylthio, ethylthio, etc.), arylthio groups (phenylthio, etc.), alkenyl groups (vinyl, 1-propenyl, etc.), acyloxy groups (acetoxy, acryloyloxy, methacryloyloxy, etc.), alkoxycarbonyl groups (methoxycarbonyl, ethoxy) Carbonyl), arylo Xyloxycarbonyl group (phenoxycarbonyl, etc.), carbamoyl group (carbamoyl, N-methylcarbamoyl, N, N-dimethylcarbamoyl, N-methyl-N-octylcarbamoyl, etc.), acylamino group (acetylamino, benzoylamino, acrylamino, methacryl) Amino) and the like, and these substituents may be further substituted.

When there are a plurality of R ^{10 s} , at least one of them is preferably a substituted alkyl group or a substituted aryl group.
Among the organosilane compounds represented by the general formula (6), an organosilane compound having a vinyl polymerizable substituent represented by the following general formula (7) is preferable.

In the general formula (7), R ¹ represents a hydrogen atom, a methyl group, a methoxy group, an alkoxycarbonyl group, a cyano group, a fluorine atom, or a chlorine atom. Examples of the alkoxycarbonyl group include a methoxycarbonyl group and an ethoxycarbonyl group. A hydrogen atom, a methyl group, a methoxy group, a methoxycarbonyl group, a cyano group, a fluorine atom, and a chlorine atom are preferable, a hydrogen atom, a methyl group, a methoxycarbonyl group, a fluorine atom, and a chlorine atom are more preferable, and a hydrogen atom and a methyl group Is particularly preferred.
Y represents a single bond, or ^* -COO- ^** , ^* -CONH- ^** , or ^* -O- ^**, and a single bond, ^* -COO- ^** , or ^* -CONH- ^** Preferably, a single bond and ^* -COO- ^** are more preferable, and ^* -COO- ^** is particularly preferable. ^* Represents a position bonded to ═C (R ¹ ) —, and ^** represents a position bonded to L.

  In the general formula (7), L represents a divalent linking chain. Specifically, a substituted or unsubstituted alkylene group, a substituted or unsubstituted arylene group, a substituted or unsubstituted alkylene group having a linking group (for example, ether, ester, amide, etc.) inside, and a linking group inside. A substituted or unsubstituted arylene group, a substituted or unsubstituted alkylene group, a substituted or unsubstituted arylene group, an alkylene group having a linking group therein is preferred, an unsubstituted alkylene group, an unsubstituted arylene group Further, an alkylene group having an ether or ester linking group inside is more preferable, an unsubstituted alkylene group, and an alkylene group having an ether or ester linking group inside is particularly preferable. Examples of the substituent include a halogen, a hydroxyl group, a mercapto group, a carboxyl group, an epoxy group, an alkyl group, and an aryl group, and these substituents may be further substituted.

In the general formula (7), n represents 0 or 1. When a plurality of X are present, the plurality of X may be the same or different. n is preferably 0.
In the general formula (7), R ¹⁰ has the same meaning as in the general formula (6), and a substituted or unsubstituted alkyl group or an unsubstituted aryl group is preferable. An unsubstituted alkyl group or an unsubstituted aryl group is preferable. Groups are more preferred.
Moreover, in the said General formula (7), X is synonymous with General formula (6), A halogen atom, a hydroxyl group, and an unsubstituted alkoxy group are preferable, A chlorine atom, a hydroxyl group, and C1-C6 unsubstituted carbon are preferable. An alkoxy group is more preferred, a hydroxyl group and an alkoxy group having 1 to 3 carbon atoms are more preferred, and a methoxy group is particularly preferred.

  Two or more compounds of the general formula (6) and the general formula (7) may be used in combination. Although the specific example of a compound represented by General formula (6) and General formula (7) below is shown, it is not limited to the following compounds.

  Of the above (M-1) to (M-10), (M-1), (M-2), and (M-5) are particularly preferable.

The hydrolyzate and / or partial condensate of the organosilane compound is generally produced by treating the organosilane compound in the presence of a catalyst.
Catalysts include inorganic acids such as hydrochloric acid, sulfuric acid and nitric acid; organic acids such as oxalic acid, acetic acid, formic acid, methanesulfonic acid and toluenesulfonic acid; inorganic bases such as sodium hydroxide, potassium hydroxide and ammonia; triethylamine, Examples thereof include organic bases such as pyridine; metal alkoxides such as triisopropoxyaluminum and tetrabutoxyzirconium; metal chelate compounds having a metal such as Zr, Ti or Al as a central metal.
In the present invention, it is preferable to use a metal chelate compound, an acid catalyst of inorganic acids and organic acids. Inorganic acids are preferably hydrochloric acid and sulfuric acid, and organic acids are preferably those having an acid dissociation constant in water (pKa value (25 ° C.)) of 4.5 or less, and an acid dissociation constant in hydrochloric acid, sulfuric acid and water of 3 or less. An organic acid having an acid dissociation constant of 2.5 or less is more preferable, and an organic acid having an acid dissociation constant of 2.5 or less in water is particularly preferable. Specifically, methanesulfonic acid, oxalic acid, phthalic acid, and malonic acid are preferable, and oxalic acid is particularly preferable among them.

As the metal chelate compound, (wherein, ^{R 3} represents an alkyl group having 1 to 10 carbon atoms) Formula ^R 3 OH alcohol and ^R 4 COCH ₂ COR ⁵ (formula represented by, ^{R 4} is the number of carbon atoms 1 to 10 alkyl groups, R ⁵ is an alkyl group having 1 to 10 carbon atoms or a compound represented by an alkoxy group having 1 to 10 carbon atoms) and selected from Zr, Ti, and Al. Any metal having a central metal as the metal can be used without any particular limitation. Within this category, two or more metal chelate compounds may be used in combination.
The metal chelate compound used in the present invention has the general formula Zr (OR ³ ) p 1 (R ⁴ COCHCOR ⁵ ) p 2, Ti (OR ³ ) q 1 (R ⁴ COCHCOR ⁵ ) q 2, and Al (OR ³ ) r 1 (R ⁴ ). Those selected from the group of compounds represented by COCHCOR ⁵ ) r2 are preferred, and serve to promote the condensation reaction of the hydrolyzate and / or partial condensate of the organosilane compound.
R ³ and R ⁴ in the metal chelate compound may be the same or different, and an alkyl group having 1 to 10 carbon atoms, specifically, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, a sec-butyl group, a t-butyl group, an n-pentyl group, a phenyl group, and the like. R5 is the same alkyl group having 1 to 10 carbon atoms as described above, or an alkoxy group having 1 to 10 carbon atoms, such as a methoxy group, an ethoxy group, an n-propoxy group, an i-propoxy group, and an n-butoxy group. , Sec-butoxy group, t-butoxy group and the like. Moreover, p1, p2, q1, q2, r1, and r2 in the metal chelate compound represent integers determined so as to be p1 + p2 = 4, q1 + q2 = 4, and r1 + r2 = 3, respectively.

Specific examples of these metal chelate compounds include tri-n-butoxyethylacetoacetate zirconium, di-n-butoxybis (ethylacetoacetate) zirconium, n-butoxytris (ethylacetoacetate) zirconium, tetrakis (n-propylacetate). Zirconium chelate compounds such as acetate) zirconium, tetrakis (acetylacetoacetate) zirconium, tetrakis (ethylacetoacetate) zirconium; diisopropoxy bis (ethylacetoacetate) titanium, diisopropoxy bis (acetylacetate) titanium, diiso Titanium chelate compounds such as propoxy bis (acetylacetone) titanium; diisopropoxyethyl acetoacetate aluminum, diisopropyl Poxyacetylacetonate aluminum, isopropoxybis (ethylacetoacetate) aluminum, isopropoxybis (acetylacetonate) aluminum, tris (ethylacetoacetate) aluminum, tris (acetylacetonato) aluminum, monoacetylacetonate bis (ethyl) An aluminum chelate compound such as acetoacetate) aluminum.
Among these metal chelate compounds, tri-n-butoxyethyl acetoacetate zirconium, diisopropoxybis (acetylacetonato) titanium, diisopropoxyethyl acetoacetate aluminum, and tris (ethyl acetoacetate) aluminum are preferable. These metal chelate compounds can be used individually by 1 type or in mixture of 2 or more types. Moreover, the partial hydrolyzate of these metal chelate compounds can also be used.

  In the present invention, it is preferable that a β-diketone compound and / or a β-ketoester compound is further added to the curable composition. This will be further described below.

The β-diketone compound and / or β-ketoester compound represented by the general formula R ⁴ COCH ₂ COR ⁵ is used in the present invention, and is used as a stability improver for the curable composition used in the present invention. It works.
Here, R ⁴ represents an alkyl group having 1 to 10 carbon atoms, and R ⁵ represents an alkyl group having 1 to 10 carbon atoms or an alkoxy group having 1 to 10 carbon atoms. That is, by coordinating with the metal atom in the metal chelate compound (zirconium, titanium and / or aluminum compound), the condensation reaction of the hydrolyzate and / or partial condensate of the organosilane compound by these metal chelate compounds is performed. It is considered that the promoting action is suppressed and the storage stability of the resulting composition is improved. R ⁴ and R ⁵ constituting the β- diketone compound and / or β- ketoester compound are the same as R ⁴ and R ⁵ constituting the metal chelate compound.

  Specific examples of the β-diketone compound and / or β-ketoester compound include acetylacetone, methyl acetoacetate, ethyl acetoacetate, acetoacetate-n-propyl, acetoacetate-i-propyl, acetoacetate-n-butyl, acetoacetate. Acetic acid-sec-butyl, acetoacetic acid-t-butyl, 2,4-hexane-dione, 2,4-heptane-dione, 3,5-heptane-dione, 2,4-octane-dione, 2,4-nonane -Dione, 5-methyl-hexane-dione, etc. are mentioned. Of these, ethyl acetoacetate and acetylacetone are preferred, and acetylacetone is particularly preferred. These β-diketone compounds and / or β-ketoester compounds may be used alone or in combination of two or more. In this invention, 2 mol or more is preferable with respect to 1 mol of metal chelate compounds, and, as for (beta) -diketone compound and / or (beta) -ketoester compound, it is more preferable that 3-20 mol is used. Within the above range, good storage stability can be obtained.

The compounding amount of the organosilane compound is preferably 0.1 to 50% by mass, more preferably 0.5 to 20% by mass, and still more preferably 1 to 10% by mass based on the total solid content of the low refractive index layer.
The organosilane compound may be added directly to the curable composition (coating solution for anti-glare layer, low refractive index layer, etc.), but the organosilane compound is treated in the presence of a catalyst in advance to prepare the organosilane compound. It is preferable to prepare a silane compound hydrolyzate and / or a partial condensate, and prepare the curable composition using the obtained reaction solution (sol solution). In the present invention, first, the organosilane compound A composition containing a hydrolyzate and / or a partial condensate and a metal chelate compound is prepared, and a solution obtained by adding a β-diketone compound and / or a β-ketoester compound thereto is added to at least an antiglare layer or a low refractive index layer. It is preferable to coat it in a single layer coating solution.
In the present invention, both the antiglare layer and the low refractive index layer contain a hydrolyzate of organosilane and / or a partial condensate thereof represented by the general formula (6). A cured film formed by applying and curing is preferable.

  5-100 mass% is preferable, the usage-amount of the sol component of the organosilane with respect to a fluorine-containing polymer in a low refractive index layer has more preferable 5-40 mass%, 8-35 mass% is still more preferable, 10-30 mass % Is particularly preferred. If the amount used is small, it is difficult to obtain the effect of the present invention, and if the amount used is too large, the refractive index increases or the shape / surface shape of the film deteriorates.

  An inorganic filler other than the above-described inorganic fine particles can be added to the curable composition in an addition amount within a range that does not impair the desired effect of the present invention. As the inorganic filler, inorganic fine particles described for the antiglare layer are preferable, and it is particularly preferable to add a material that can impart conductivity, such as indium, tin, and antimony, within a range that does not greatly affect the refractive index.

-Sol-gel material-
Various sol-gel materials can also be used as the material for the low refractive index layer. As such a sol-gel material, metal alcoholates (alcolates such as silane, titanium, aluminum, and zirconium), organoalkoxy metal compounds, and hydrolysates thereof can be used. In particular, alkoxysilane, organoalkoxysilane and its hydrolyzate are preferable. Examples of these include tetraalkoxysilane (tetramethoxysilane, tetraethoxysilane, etc.), alkyltrialkoxysilane (methyltrimethoxysilane, ethyltrimethoxysilane, etc.), aryltrialkoxysilane (phenyltrimethoxysilane, etc.), dialkyl. Examples thereof include dialkoxysilane and diaryl dialkoxysilane. In addition, organoalkoxysilanes having various functional groups (vinyl trialkoxysilane, methylvinyl dialkoxysilane, γ-glycidyloxypropyltrialkoxysilane, γ-glycidyloxypropylmethyl dialkoxysilane, β- (3,4-epoxy) Dicyclohexyl) ethyltrialkoxysilane, γ-methacryloyloxypropyltrialkoxysilane, γ-aminopropyltrialkoxysilane, γ-mercaptopropyltrialkoxysilane, γ-chloropropyltrialkoxysilane, etc.), perfluoroalkyl group-containing silane compounds ( For example, it is also preferable to use (heptadecafluoro-1,1,2,2-tetradecyl) triethoxysilane, 3,3,3-trifluoropropyltrimethoxysilane, etc.). In particular, the use of a fluorine-containing silane compound is preferable in terms of lowering the refractive index of the layer and imparting water repellency and oil repellency, and it is also preferable to contain it as the above-mentioned (A) fluorine-containing compound.

-Other substances contained in the curable composition for the low refractive index layer-
In the curable composition, various additives, a radical polymerization initiator, and a cationic polymerization initiator are added to the above-mentioned (A) fluorine-containing compound, (B) inorganic fine particles, and (C) an organosilane compound as necessary. Further, these are prepared by dissolving them in a suitable solvent. In this case, the concentration of the solid content is appropriately selected according to the use, but generally, it is preferably about 0.01 to 60% by mass, more preferably 0.5 to 50% by mass, and 1 to 20% by mass. The degree is further preferred.

  From the viewpoint of interfacial adhesion between the lower refractive index layer and the lower layer that is in direct contact, a curing agent such as a polyfunctional (meth) acrylate compound, polyfunctional epoxy compound, polyisocyanate compound, aminoplast, polybasic acid, or an anhydride thereof. Can also be added in small amounts. When adding these, it is preferable to set it as the range of 30 mass% or less with respect to the total solid of a low-refractive-index layer film, It is more preferable to set it as the range of 20 mass% or less, The range of 10 mass% or less It is particularly preferable that

  In addition, for the purpose of imparting properties such as antifouling properties, water resistance, chemical resistance, and slipping properties, a known silicone compound or fluorine compound antifouling agent, slipping agent, and the like may be appropriately added. When these additives are added, it is preferably added in the range of 0.01 to 20% by mass of the total solid content of the low refractive index layer, and may be added in the range of 0.05 to 10% by mass. More preferably, it is more preferable to add in the range of 0.1 to 5% by mass.

Preferable examples of the silicone compound include those having a substituent at the terminal and / or side chain of a compound chain containing a plurality of dimethylsilyloxy units as repeating units. The compound chain containing dimethylsilyloxy as a repeating unit may contain a structural unit other than dimethylsilyloxy. The substituents may be the same or different, and a plurality of substituents are preferable. Examples of preferred substituents include acryloyl group, methacryloyl group, vinyl group, aryl group, cinnamoyl group, epoxy group, oxetanyl group, hydroxyl group, fluoroalkyl group, polyoxyalkylene group, carboxyl group, amino group and the like. It is done. Although there is no restriction | limiting in particular in molecular weight, It is preferable that it is 100,000 or less, It is more preferable that it is 50,000 or less, It is still more preferable that it is 3,000-30,000. Although there is no restriction | limiting in particular in silicone atom content of a silicone type compound, It is preferable that it is 18.0 mass% or more, It is more preferable that it is 25.0-37.8 mass%, 30.0-37.0 More preferably, it is mass%.
Examples of preferable silicone compounds include X-22-174DX, X-22-2426, X-22-164B, X22-164C, X-22-170DX, X-22-176D, X, manufactured by Shin-Etsu Chemical Co., Ltd. -22-1821 (named above), Chisso Corporation, FM-0725, FM-7725, FM-4421, FM-5521, FM6621, FM-1121, Gelest DMS-U22, RMS-033, RMS- 083, UMS-182, DMS-H21, DMS-H31, HMS-301, FMS121, FMS123, FMS131, FMS141, FMS221 (and above are trade names) and the like, but are not limited thereto.

As the fluorine compound, a compound having a fluoroalkyl group is preferable. The fluoroalkyl group preferably has 1 to 20 carbon atoms, more preferably 1 to 10 carbon atoms, and a straight chain (for example, —CF ₂ CF ₃ , —CH ₂ (CF ₂ ) ₄ H, —CH ₂ (CF ₂ ) ₈ CF ₃ , —CH ₂ CH ₂ (CF ₂ ) ₄ H, etc.), but branched structures (eg, —CH (CF ₃ ) ₂ , —CH ₂ CF (CF ₃ ) ₂ , —CH (CH ₃ )) CF ₂ CF ₃ , —CH (CH ₃ ) (CF ₂ ) ₅ CF ₂ H, and the like) may be an alicyclic structure (preferably a 5- or 6-membered ring such as a perfluorocyclohexyl group, A fluorocyclopentyl group or an alkyl group substituted with these, and may have an ether bond (for example, —CH ₂ OCH ₂ CF ₂ CF ₃ , —CH ₂ CH ₂ OCH ₂ C ₄ F). ₈ H, —CH ₂ CH _{2 OCH 2 CH 2 C 8 F} 17, -CH 2 CH 2 OCF 2 CF 2 OCF 2 CF 2 H , etc.). A plurality of the fluoroalkyl groups may be contained in the same molecule.
It is preferable that the fluorine-based compound further has a substituent that contributes to bond formation or compatibility with the low refractive index layer film. The substituents may be the same or different, and a plurality of substituents are preferable. Examples of preferred substituents include acryloyl group, methacryloyl group, vinyl group, aryl group, cinnamoyl group, epoxy group, oxetanyl group, hydroxyl group, polyoxyalkylene group, carboxyl group, amino group and the like. The fluorine-based compound may be a polymer or an oligomer with a compound not containing a fluorine atom, and the molecular weight is not particularly limited. Although there is no restriction | limiting in particular in fluorine atom content of a fluorine-type compound, It is preferable that it is 20 mass% or more, It is more preferable that it is 30-70 mass%, It is still more preferable that it is 40-70 mass%. Examples of preferable fluorine-based compounds include Daikin Chemical Industries, Ltd., R-2020, M-2020, R-3833, M-3833 (named above), Dainippon Ink Co., Ltd., MegaFac F- 171, F-172, F-179A, defender MCF-300 (trade name) and the like, but are not limited thereto.

  In addition, the aforementioned silicone compound or fluorine compound, which can be appropriately added for the purpose of imparting properties such as antifouling property, water resistance, chemical resistance and slipperiness, has a molecular structure for the low refractive index layer. (A) It is also preferable to include in the molecular structure of the fluorine-containing compound in the curable composition. That is, it is desirable to contain in the form of a block or a graph in the molecular structure of the aforementioned fluorine-containing polymer or fluorine-containing sol-gel.

  For the purpose of imparting properties such as dust resistance and antistatic properties, a known cationic surfactant or a dustproof agent such as a polyoxyalkylene compound, an antistatic agent, or the like can be appropriately added. These dustproofing agent and antistatic agent may contain the structural unit as a part of the function in the above-mentioned silicone compound or fluorine compound. When these are added as additives, it is preferably added in the range of 0.01 to 20% by mass, and more preferably in the range of 0.05 to 10% by mass, based on the total solid content of the low n layer. Preferably, it is more preferable to add in 0.1-5 mass%. Examples of preferred compounds include, but are not limited to, Dainippon Ink Co., Ltd., MegaFace F-150 (trade name), Toray Dow Corning Co., Ltd., SH-3748 (trade name), and the like. Do not mean.

-Solvent for low refractive index layer-
As the solvent used in the coating composition for forming the low refractive index layer of the present invention, it is possible to dissolve or disperse each component, to easily form a uniform surface in the coating process and the drying process, and liquid storage stability. Can be used, and various solvents selected from the viewpoint of having an appropriate saturated vapor pressure can be used. From the viewpoint of the drying load, it is preferable that the main component is a solvent having a boiling point of 100 ° C. or lower at normal pressure and room temperature, and it is more preferable to contain a small amount of a solvent having a boiling point of 100 ° C. or higher in order to adjust the drying speed. .
Examples of the solvent having a boiling point of 100 ° C. or lower include hydrocarbons such as hexane (boiling point 68.7 ° C.), heptane (98.4 ° C.), cyclohexane (80.7 ° C.), benzene (80.1 ° C.), Halogenated carbonization such as dichloromethane (39.8 ° C), chloroform (61.2 ° C), carbon tetrachloride (76.8 ° C), 1,2-dichloroethane (83.5 ° C), trichloroethylene (87.2 ° C) Hydrogens, diethyl ether (34.6 ° C), diisopropyl ether (68.5 ° C), dipropyl ether (90.5 ° C), tetrahydrofuran (66 ° C) and other ethers, ethyl formate (54.2 ° C), Esters such as methyl acetate (57.8 ° C.), ethyl acetate (77.1 ° C.), isopropyl acetate (89 ° C.), acetone (56.1 ° C.), 2-butanone (methyl ethyl) Ketones such as 79.6 ° C, the same as ketone, methanol (64.5 ° C), ethanol (78.3 ° C), 2-propanol (82.4 ° C), 1-propanol (97.2 ° C), etc. Alcohols, cyano compounds such as acetonitrile (81.6 ° C.), propionitrile (97.4 ° C.), carbon disulfide (46.2 ° C.), and the like. Of these, ketones and esters are preferred, and ketones are more preferred. Among the ketones, 2-butanone is particularly preferable.
Examples of the solvent having a boiling point of 100 ° C. or more include, for example, octane (125.7 ° C.), toluene (110.6 ° C.), xylene (138 ° C.), tetrachloroethylene (121.2 ° C.), and chlorobenzene (131.7 ° C.). , Dioxane (101.3 ° C), dibutyl ether (142.4 ° C), isobutyl acetate (118 ° C), cyclohexanone (155.7 ° C), 2-methyl-4-pentanone (same as MIBK, 115.9 ° C) 1-butanol (117.7 ° C.), N, N-dimethylformamide (153 ° C.), N, N-dimethylacetamide (166 ° C.), dimethyl sulfoxide (189 ° C.) and the like. Among these, cyclohexanone and 2-methyl-4-pentanone are preferable.

<< layer formation >>
The first coating layer, the easy-adhesion layer, and the second coating layer, hard coat layer, low refractive index layer or other layer used in the present invention are coated on the transparent substrate film. Then, heating and drying are performed, and then, if necessary, the monomer and the curable resin for forming each layer are cured by light irradiation and / or heating. Thereby, each layer is formed.

  Although the coating method of each layer of the film of the present invention is not particularly limited, a dip coating method, an air knife coating method, a curtain coating method, a roller coating method, a wire bar coating method, a gravure coating method, an extrusion coating method (die coating method) ( U.S. Pat. No. 2,681,294) and known methods such as a micro gravure coating method are used. Among them, a micro gravure coating method and a die coating method are preferable, and a die coating method is preferably used in order to supply with high productivity. At this time, in order to optimize the viscosity characteristic of the liquid for the coating apparatus during film formation, a method of adjusting the liquid viscosity of the coating liquid by adding a viscosity modifier such as a thickener to the coating liquid is also used. You can also.

  Drying is preferably performed under conditions where the concentration of the organic solvent in the applied liquid film is 5% by mass or less after drying, more preferably 2% by mass or less, and even more preferably 1% by mass or less. The drying conditions are affected by the thermal strength of the substrate, the conveyance speed, the length of the drying process, and the like, but it is preferable that the organic solvent content is as low as possible in terms of film hardness and adhesion prevention. When an organic solvent is not contained, the drying step can be omitted and ultraviolet irradiation can be performed immediately after coating.

  The first coating layer and the easy adhesion layer of the present invention may be subjected to heat treatment in order to increase the crystallinity. The preferable heat treatment temperature is 40 to 130 ° C., and the heat treatment time can be appropriately determined according to the required crystallinity, but is usually about 5 minutes to 48 hours.

  Furthermore, for the purpose of improving the adhesion between the transparent substrate film and the first coating layer, one or both surfaces of the transparent substrate film can be subjected to a surface treatment by an oxidation method, an unevenness method, or the like as desired. Examples of the oxidation method include corona discharge treatment, glow discharge treatment, chromic acid treatment (wet), flame treatment, hot air treatment, ozone / ultraviolet irradiation treatment, and the like.

<< Antistatic Layer >>
An antistatic layer may be formed between the transparent substrate film and the first coating layer. In the antistatic layer of the present invention, the haze of the low chargeable substrate film obtained by providing the antistatic layer on the transparent substrate film is 3% or less, and the surface of the surface layer of the obtained polarizing plate protective film Conductivity is imparted so that the electric resistance is in the range of 1 × 10 ⁶ to 1 × 10 ¹¹ Ω. By providing the antistatic layer, it is possible to suppress the occurrence of trouble with dust caused by static electricity that occurs in the manufacturing process of handling the plastic support.

  The antistatic layer is a layer containing conductive metal oxide particles, and generally further contains a binder. The conductive metal oxide particles are preferably acicular particles having a major axis to minor axis ratio (major axis / minor axis) in the range of 3 to 50. In particular, those having a major axis / minor axis in the range of 10 to 50 are preferable. The minor axis of such acicular particles is preferably in the range of 0.001 to 0.1 μm, and particularly preferably in the range of 0.01 to 0.02 μm. The major axis is preferably in the range of 0.1 to 5.0 μm, and particularly preferably in the range of 0.1 to 2.0 μm.

Examples of the material of the conductive metal oxide particles include ZnO, TiO ₂ , SnO ₂ , Al ₂ O ₃ , In ₂ O ₃ , MgO, BaO and MoO ₃ , and composite oxides thereof, and metal oxides thereof. In addition, metal oxides further containing different atoms can be mentioned.
As the metal oxide, SnO ₂ , ZnO, Al ₂ O ₃ , TiO ₂ , In ₂ O ₃ and MgO are preferable, SnO ₂ , ZnO, In ₂ O ₂ and TiO ₂ are more preferable, and SnO ₂ is more preferable. preferable.
Examples of containing a small amount of different atoms include Zn or Al, In, TiO ₂ Nb or Ta, In ₂ O ₃ Sn, and SnO ₂ Sb, Nb or halogen elements. What doped 0.01-30 mol% (preferably 0.1-10 mol%) of an element is mentioned. If the amount of the different element added is less than 0.01 mol%, sufficient conductivity cannot be imparted to the oxide or composite oxide. If it exceeds 30 mol%, the degree of blackening of the particles increases, and charging Since the prevention layer is dark, it is not suitable as a protective film for polarizing plates.
Therefore, in the present invention, the material of the conductive metal oxide particles is preferably one containing a small amount of different elements with respect to the metal oxide or the composite metal oxide. Also preferred are those containing an oxygen defect in the crystal structure.
As the conductive metal oxide particles containing a small amount of different atoms, antimony-doped SnO ₂ particles are preferable, and antimony-doped SnO ₂ particles are particularly preferable.
Therefore, in the present invention, it is advantageous to use a metal oxide particle such as antimony-doped SnO ₂ having the short axis and long axis dimensions for forming an antistatic layer that is transparent and has good conductivity. is there. Thereby, the protective film for polarizing plates which has a low-chargeable base film and the surface electrical resistance of a surface layer is in the range of 1 × 10 ⁶ to 1 × 10 ¹¹ Ω can be easily obtained.

About the reason why an antistatic layer which is transparent and has good conductivity can be advantageously formed by using acicular metal oxide particles having the dimensions of the short axis and the long axis (eg, antimony-doped SnO ₂ ). Is considered as follows.
In the antistatic layer, the needle-like metal oxide particles extend long in the major axis direction parallel to the surface of the antistatic layer, but the length of the minor axis in the thickness direction of the layer. It only occupies. Since such acicular metal oxide particles are long in the major axis direction as described above, they are easier to contact with each other than ordinary spherical particles, and high conductivity can be obtained even in a small amount.
Accordingly, the surface electrical resistance can be reduced without impairing transparency.
Further, in the needle-shaped metal oxide particles, the minor axis diameter is usually smaller than or substantially the same as the thickness of the antistatic layer, and hardly protrudes to the surface. For this reason, it is almost completely covered by the first covering layer provided on the antistatic layer.
Therefore, the advantage that there is almost no occurrence of powder falling, which is the detachment of the protruding portion from the layer, during the transport of the protective film for polarizing plate can be obtained.

The antistatic layer of the present invention generally contains a binder that disperses and supports conductive metal oxide particles. As a material for the binder, various polymers such as an acrylic resin, a vinyl resin, a polyurethane resin, and a polyester resin can be used. From the viewpoint of preventing powder falling, a cured product of a polymer (preferably an acrylic resin, a vinyl resin, a polyurethane resin, or a polyester resin) and a carbodiimide compound is preferable.
In the present invention, from the viewpoint of maintaining a good working environment and preventing air pollution, it is preferable to use either a water-soluble polymer or a carbodiimide compound, or an aqueous dispersion such as an emulsion.
Further, the polymer has any group of a methylol group, a hydroxyl group, a carboxyl group, and an amino group so that a crosslinking reaction with the carbodiimide compound is possible. A hydroxyl group and a carboxyl group are preferred, and a carboxyl group is particularly preferred. The content of the hydroxyl group or carboxyl group in the polymer is preferably 0.0001 to 1 equivalent / 1 kg, particularly preferably 0.001 to 1 equivalent / 1 kg.

Acrylic resins include acrylic acid esters such as acrylic acid and alkyl acrylate, homopolymers of monomers such as acrylamide, acrylonitrile, methacrylic acid esters such as methacrylic acid and alkyl methacrylate, methacrylamide and methacrylonitrile. Or the copolymer obtained by superposition | polymerization of 2 or more types of these monomers is mentioned.
Among these, homopolymers of monomers of acrylic acid esters such as alkyl acrylates and methacrylic acid esters such as alkyl methacrylates, or copolymers obtained by polymerization of two or more of these monomers preferable. For example, the homopolymer of the monomer in any one of acrylic acid ester and methacrylic acid ester which has a C1-C6 alkyl group, or the copolymer obtained by superposition | polymerization of these 2 or more types of monomers is mentioned. The acrylic resin has the above composition as a main component and, for example, partially uses a monomer having any group of a methylol group, a hydroxyl group, a carboxyl group, and an amino group so that a crosslinking reaction with a carbodiimide compound is possible. The resulting polymer.

  Examples of the vinyl resin include polyvinyl alcohol, acid-modified polyvinyl alcohol, polyvinyl formal, polyvinyl butyral, polyvinyl methyl ether, polyolefin, ethylene / butadiene copolymer, polyvinyl acetate, vinyl chloride / vinyl acetate copolymer, vinyl chloride / ( And a (meth) acrylic acid ester copolymer and an ethylene / vinyl acetate copolymer (preferably ethylene / vinyl acetate / (meth) acrylic acid ester copolymer). Among these, polyvinyl alcohol, acid-modified polyvinyl alcohol, polyvinyl polymer, polyolefin, ethylene / butadiene copolymer and ethylene / vinyl acetate copolymer (preferably ethylene / vinyl acetate / acrylic acid ester copolymer). Is preferred. The vinyl resin is polyvinyl alcohol, acid-modified polyvinyl alcohol, polyvinyl formal, polyvinyl butyral, polyvinyl methyl ether, and polyvinyl acetate so that a crosslinking reaction with a carbodiimide compound is possible. The polymer having a hydroxyl group is left as it is, and the other polymer is, for example, a crosslinkable polymer by partially using a monomer having any of a methylol group, a hydroxyl group, a carboxyl group, and an amino group.

  Examples of the polyurethane resin include polyhydroxy compounds (eg, ethylene glycol, propylene glycol, glycerin, trimethylolpropane), aliphatic polyester polyols obtained by reaction of polyhydroxy compounds and polybasic acids, polyether polyols (eg, Poly (oxypropylene ether) polyol, poly (oxyethylene-propylene ether) polyol), polycarbonate-based polyol, and polyethylene terephthalate polyol, or a polyurethane derived from a mixture thereof and polyisocyanate can be used. In the polyurethane resin, for example, the hydroxyl group remaining unreacted after the reaction between polyol and polyisocyanate can be used as a functional group capable of crosslinking reaction with a carbodiimide compound.

  As the polyester resin, generally used is a polymer obtained by reacting a polyhydroxy compound (eg, ethylene glycol, propylene glycol, glycerin, trimethylolpropane) with a polybasic acid. In the above-mentioned polyester resin, for example, the hydroxyl group and carboxyl group remaining unreacted after the reaction between the polyol and the polybasic acid can be used as a functional group capable of crosslinking reaction with the carbodiimide compound. Of course, a third component having a functional group such as a hydroxyl group may be added.

  Among the above polymers, acrylic resins and polyurethane resins are preferable, and acrylic resins are particularly preferable.

As the carbodiimide compound used in the present invention, it is preferable to use a compound part having a plurality of carbodiimide structures in the molecule.
Polycarbodiimide is usually synthesized by a condensation reaction of organic diisocyanate. Here, the organic group of the organic diisocyanate used for the synthesis of the compound having a plurality of carbodiimide structures in the molecule is not particularly limited, and either aromatic or aliphatic, or a mixed system thereof can be used. An aliphatic system is particularly preferred from the viewpoint of reactivity.
As the synthetic raw material, organic isocyanate, organic diisocyanate, organic triisocyanate and the like are used.
As examples of organic isocyanates, aromatic isocyanates, aliphatic isocyanates, and mixtures thereof can be used.
Specifically, 4,4′-diphenylmethane diisocyanate, 4,4-diphenyldimethylmethane diisocyanate, 1,4-phenylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, hexamethylene diisocyanate, cyclohexane Diisocyanate, xylylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 4,4′-dicyclohexylmethane diisocyanate, 1,3-phenylene diisocyanate, etc. are used. As organic monoisocyanates, isophorone isocyanate, phenyl isocyanate are used. Cyclohexyl isocyanate, butyl isocyanate, naphthyl isocyanate and the like are used.
Moreover, the carbodiimide type compound that can be used in the present invention is also available as a commercial product such as Carbodilite V-02-L2 (trade name: manufactured by Nisshinbo Co., Ltd.).
It is preferable to add the carbodiimide type compound of this invention in the range of 1-200 mass% with respect to a binder, and it is more preferable to add in the range of 5-100 mass%.

  In order to form the antistatic layer of the present invention, first, for example, a dispersion obtained by dispersing the conductive metal oxide particles as they are or in a solvent such as water (including a dispersant and a binder as necessary) An antistatic layer-forming coating solution is prepared by adding and mixing (dispersing as necessary) an aqueous dispersion or aqueous solution containing the binder (eg, polymer, carbodiimide compound and appropriate additive). The antistatic layer is a coating method generally known on the surface of a plastic film such as polyester (the side where no photosensitive layer is provided), such as dip coating, air knife coating, It can be applied by a curtain coating method, a wire bar coating method, a gravure coating method, an extrusion coating method or the like. The plastic film such as polyester to be applied may be any of before sequential biaxial stretching, before simultaneous biaxial stretching, after uniaxial stretching and before re-stretching, or after biaxial stretching. The surface of the plastic substrate film to which the coating solution for forming the antistatic layer is applied is preferably subjected to surface treatment such as ultraviolet treatment, corona treatment, glow discharge treatment and the like in advance.

The layer thickness of the antistatic layer of the present invention is preferably in the range of 0.01 to 1 μm, more preferably in the range of 0.01 to 0.2 μm. If the coating agent is less than 0.01 μm, it is difficult to uniformly apply the coating agent, and uneven coating tends to occur on the product. If it exceeds 1 μm, the antistatic performance and scratch resistance may be inferior.
The conductive metal oxide particles are preferably contained in the antistatic layer in the range of 10 to 1,000% by mass with respect to the binder (for example, the total of the polymer and the carbodiimide compound). The range of 500% by mass is more preferable. If it is less than 10% by mass, sufficient antistatic properties cannot be obtained, and if it exceeds 1,000% by mass, the haze becomes too high.

  The antistatic layer of the present invention and the following surface layer can be used in combination with additives such as a matting agent, a surfactant, and a slipping agent, if necessary. Examples of the matting agent include particles of oxides such as silicon oxide, aluminum oxide, and magnesium oxide having a particle diameter of 0.001 to 10 μm, and particles such as a polymer or a copolymer such as polymethyl methacrylate and polystyrene. .

Examples of the surfactant include known anionic surfactants, cationic surfactants, amphoteric surfactants, and nonionic surfactants.
Examples of the slip agent include natural waxes such as carnauba wax, phosphate esters of higher alcohols having 8 to 22 carbon atoms or amino salts thereof; palmitic acid, stearic acid, behenic acid, and esters thereof; and silicone compounds. It is done.

The protective film of the present invention having the first coating layer, the easy-adhesion layer, the hard coat layer, etc. in this order on the transparent substrate film is placed on the outermost surface side of the liquid crystal display device among the surface protective films of the two polarizing films. When creating a polarizing plate by using the protective film, the surface of the transparent substrate film opposite to the first coating layer, that is, the surface to be bonded to the polarizing film is hydrophilized. It is preferable to improve the adhesion on the bonding surface.
The hydrophilized surface is effective for improving the adhesion with an adhesive layer containing polyvinyl alcohol. As the hydrophilic treatment, the following saponification treatment is preferably performed.

[Saponification]
(1) Method of immersing in alkali solution This is a technique in which a protective film for polarizing plate is immersed in an alkali solution under appropriate conditions, and all surfaces having reactivity with alkali on the entire surface of the film are saponified. It is preferable from the viewpoint of cost because it does not require any equipment.
The alkaline liquid is preferably a sodium hydroxide aqueous solution. The concentration is preferably 0.5 to 3 mol / L, and more preferably 1 to 2 mol / L. Moreover, as a liquid temperature of an alkaline liquid, 30-75 degreeC is preferable and 40-60 degreeC is more preferable.
The combination of the saponification conditions is preferably a combination of relatively mild conditions, but can be set according to the material and configuration of the light scattering film and the antireflection film, and the target contact angle.
After being immersed in the alkaline solution, it is preferable to sufficiently wash with water or neutralize the alkaline component by immersing in a dilute acid so that the alkaline component does not remain in the film.

By performing the saponification treatment, the surface of the transparent base film opposite to the surface having the antiglare layer or the antireflection layer is hydrophilized.
The protective film for polarizing plate is used by adhering the hydrophilic surface of the transparent substrate film to the polarizing film.
The hydrophilized surface is effective for improving the adhesiveness with the adhesive layer mainly composed of polyvinyl alcohol.
In the saponification treatment, the lower the contact angle with water on the surface of the transparent substrate film opposite to the side having the antiglare layer or the low refractive index layer, the better from the viewpoint of adhesion to the polarizing film, but on the other hand, In this method, alkali damage is caused from the surface having the antiglare layer and the low refractive index layer to the inside, so that it is important to set the necessary minimum reaction conditions.
When the contact angle to water of the transparent substrate film on the opposite surface is used as an index of damage received by each layer due to alkali, 10 to 50 degrees is preferable particularly when the transparent substrate film is triacetylcellulose. -50 degrees is more preferable and 40-50 degrees is still more preferable. If it is 50 degrees or more, a problem arises in the adhesion to the polarizing film, which is not preferable. On the other hand, if it is less than 10 degrees, the damage is too great, and physical strength is impaired.

(2) Method of applying alkaline solution As a means for avoiding damage to each film in the above-mentioned immersion method, the alkaline solution is applied only to the surface opposite to the surface having the antiglare layer or the low refractive index layer under appropriate conditions. An alkaline solution coating method of coating, heating, washing with water and drying is preferably used.
The application in this case means that an alkaline solution or the like is brought into contact only with the surface to be saponified, and in addition to the application, it may be carried out by spraying or contacting a belt containing the solution. Including.
By adopting these methods, a separate facility and process for applying an alkaline solution are required, which is inferior to the immersion method (1) from the viewpoint of cost.
On the other hand, since the alkali solution contacts only the surface to be saponified, the opposite surface can have a layer using a material that is weak against the alkali solution.
For example, vapor deposition films and sol-gel films have various effects such as corrosion, dissolution, and peeling due to alkali solution, so it is not desirable to use the immersion method. Is possible.

In any of the saponification methods (1) and (2), since each layer can be formed after being unwound from a roll-shaped transparent substrate film, after the above-described antiglare antireflection film production process In addition, a series of operations may be performed.
Furthermore, a polarizing plate can be produced more efficiently than the same operation on a single wafer by continuously performing a bonding process with a polarizing plate made of a transparent base film that has been unwound in the same manner. .

(3) Method of protecting and saponifying an antiglare layer and an antireflection layer with a laminate film When the antiglare layer and / or the low refractive index layer is insufficient in resistance to an alkaline solution as in the above (2) Then, after forming the final layer, the laminate film is bonded to the surface on which the final layer is formed and then immersed in an alkaline solution to hydrophilize only the side of the triacetyl cellulose opposite to the surface on which the final layer has been formed. After being laminated, the laminate film can be peeled off.
Even in this method, only the surface opposite to the surface on which the final layer of the triacetylcellulose film is formed can be subjected to the hydrophilic treatment necessary for the protective film without damaging the antiglare layer and the low refractive index layer. . Compared with the method (2), there is an advantage that a laminate film is generated as waste, but a device for applying a special alkaline solution is unnecessary.

(4) Method of immersing in alkaline solution after forming up to antiglare layer Up to antiglare layer is resistant to alkaline solution, but when low refractive index layer is insufficiently resistant to alkaline solution, after forming up to antiglare layer It is also possible to soak both surfaces in an alkali solution to hydrophilize both surfaces, and then form a low refractive index layer on the antiglare layer.
Although the manufacturing process becomes complicated, there is an advantage that the interlayer adhesion between the antiglare layer and the low refractive index layer is improved particularly when the low refractive index layer has a hydrophilic group such as a fluorine-containing sol-gel film.

(5) Method of forming a coating on a previously saponified triacetyl cellulose film First, the triacetyl cellulose film is saponified by immersing it in an alkali solution in advance, either directly or via another layer. The coating layer may be formed. In the case of saponification by dipping in an alkaline solution, interlayer adhesion between the first coating layer and the triacetyl cellulose surface hydrophilized by saponification may deteriorate.
In such a case, after the saponification, only the surface on which the first coating layer is formed is treated with corona discharge, glow discharge or the like to remove the hydrophilic surface and then the first coating layer or other layer. It can be dealt with by forming. Further, when the first coating layer or other layer has a hydrophilic group, the interlayer adhesion may be good.

<Preparation method of polarizing plate>
The protective film for polarizing plates (first protective film) of the present invention constitutes a polarizing plate by being bonded to at least one surface of a polarizer. The other surface of the polarizer is preferably bonded with a second protective film having a moisture permeability of 700 to 3,000 g / m ² · day, and the moisture permeability of 1,000 to 1,700 g / m ² · day. More preferably, a protective film for polarizing plate can be bonded. Usually, a TAC (cellulose triacetate) film is suitably used as the second protective film.
Here, as the second protective film, a normal cellulose acetate film may be used, but the cellulose produced by a solution casting method and stretched in the width direction in the form of a roll film at a stretch ratio of 10 to 100%. An acetate film may be used.
Furthermore, in the polarizing plate of the present invention, one side is the protective film for polarizing plate of the present invention, whereas the other protective film is an optical compensation film having an optically anisotropic layer made of a liquid crystalline compound. Good.
In the polarizing plate of the present invention, one side is the protective film for polarizing plate of the present invention, whereas the in-plane retardation Re of the other protective film is 0 to 10 nm, and the retardation Rth in the thickness direction is −20. It may be a film having a thickness of ˜20 nm (for example, see paragraph number [0095] of JP-A-2005-301227).

  Examples of the polarizer include an iodine polarizing film, a dye polarizing film using a dichroic dye, and a polyene polarizing film. The iodine polarizing film and the dye polarizing film are generally produced using a polyvinyl alcohol film.

Of the two protective films installed on the polarizer, the protective film for polarizing plate (second protective film) other than the protective film for polarizing plate (first protective film) of the present invention is an optically anisotropic layer. It is also preferable that the optical compensation film has an optical compensation layer comprising
The optical compensation film (retardation film) can improve the viewing angle characteristics of the liquid crystal display screen.
A known film can be used as the optical compensation film, but the optical compensation film described in JP-A-2001-100042 is preferable in terms of widening the viewing angle.

  When the protective film for polarizing plates of the present invention is used together with a liquid crystal display device or the like, it is preferably disposed on the viewing side opposite to the liquid crystal cell.

(Liquid crystal display device)
Below, the liquid crystal display device using the polarizing plate using the protective film of this invention is demonstrated.
FIG. 3 is a cross-sectional view showing a configuration of a liquid crystal display device using the polarizing plate of the present invention.
As shown in FIG. 3, the liquid crystal display device 8 of the present invention includes a liquid crystal cell 9 and two polarizing plates 5 and 5 installed so as to sandwich the liquid crystal cell 9.
The liquid crystal display device 8 shown in FIG. 3 includes a liquid crystal cell 9 that holds a liquid crystal between two electrode substrates, and two polarizing plates 5 and 5 that are installed so as to sandwich the liquid crystal cell 9. However, the liquid crystal display device 8 of the present invention is effective even when the polarizing plate 5 is provided on at least one of the liquid crystal cells 9.
Moreover, it is preferable that the polarizing plate 5 of this invention is affixed on a liquid crystal cell through an adhesive so that the 2nd protective film 7 may oppose the liquid crystal cell 9. FIG.
Furthermore, one optically anisotropic layer may be disposed between the liquid crystal cell and one polarizing plate, or two optically anisotropic layers may be disposed between the liquid crystal cell and both polarizing plates.

  The liquid crystal cell may be a TN (Twisted Nematic) mode, a VA (Vertical Aligned Bend) mode, an OCB (Optically Compensated Bend) mode, an IPS (In-Plane Switching) mode, and an ECB (Electrically Bending mode). preferable.

<TN mode>
In a TN mode liquid crystal cell, rod-like liquid crystal molecules are substantially horizontally aligned when no voltage is applied, and are twisted and aligned at 60 to 120 °.
TN mode liquid crystal cells are particularly frequently used as color TFT liquid crystal display devices, and are described in many documents.

<VA mode>
In a VA mode liquid crystal cell, rod-like liquid crystalline molecules are aligned substantially vertically when no voltage is applied.
The VA mode liquid crystal cell includes (1) a narrowly defined VA mode liquid crystal cell in which rod-like liquid crystalline molecules are aligned substantially vertically when no voltage is applied, and substantially horizontally when a voltage is applied (Japanese Patent Laid-Open No. Hei 2-). (2) Liquid crystal cell (SID97, Digest of Tech. Papers (Proceedings) 28 (1997) 845 in which the VA mode is converted into a multi-domain (for MVA mode) in order to expand the viewing angle. (3) A liquid crystal cell in a mode (n-ASM mode) in which rod-like liquid crystalline molecules are substantially vertically aligned when no voltage is applied and twisted multi-domain alignment is applied when a voltage is applied (Preliminary Collection 58- 59 (1998)) and (4) SURVAVAL mode liquid crystal cells (announced at LCD International 98).

<OCB mode>
The OCB mode liquid crystal cell is a bend alignment mode liquid crystal cell in which rod-like liquid crystal molecules are aligned in substantially opposite directions (symmetrically) at the upper and lower portions of the liquid crystal cell. US Pat. No. 4,583,825, No. 5,410,422. Since the rod-like liquid crystal molecules are symmetrically aligned at the upper and lower portions of the liquid crystal cell, the bend alignment mode liquid crystal cell has a self-optical compensation function. Therefore, this liquid crystal mode is called an OCB (Optically Compensatory Bend) liquid crystal mode. The bend alignment mode liquid crystal display device has an advantage of high response speed.

<IPS mode>
The IPS mode liquid crystal cell is a type in which a nematic liquid crystal is switched by applying a lateral electric field. IDRC (Asia Display '95), p. 577-580, and p. 707-710.

<ECB mode>
In the ECB mode liquid crystal cell, rod-like liquid crystalline molecules are substantially horizontally aligned when no voltage is applied. The ECB mode is one of the liquid crystal display modes having the simplest structure, and is described in detail in, for example, Japanese Patent Application Laid-Open No. 5-203946.

<Brightness enhancement film>
As the brightness enhancement film, a polarization conversion element having a function of separating light emitted from a light source (backlight) into transmitted polarized light, reflected polarized light, or scattered polarized light is used. Such a brightness enhancement film can improve the emission efficiency of linearly polarized light by using retroreflected light from a reflected polarized light or scattered polarized light backlight.
An example is an anisotropic reflective polarizer. An anisotropic reflective polarizer includes an anisotropic multiple thin film that transmits linearly polarized light in one vibration direction and reflects linearly polarized light in the other vibration direction.
An example of the anisotropic multi-thin film is DBM manufactured by 3M (see, for example, JP-A-4-268505).
An example of the anisotropic reflective polarizer is a composite of a cholesteric liquid crystal layer and a λ / 4 plate. An example of such a composite is PCF manufactured by Nitto Denko (see JP-A-11-231130, etc.). An example of the anisotropic reflective polarizer is a reflective grid polarizer.
As a reflective grid polarizer, a metal grid reflective polarizer (see US Pat. No. 6,288,840, etc.) in which metal is finely processed to produce reflected polarized light in the visible light region, metal fine particles are placed in a polymer matrix. And the like (see JP-A-8-184701, etc.).
Moreover, an anisotropic scattering polarizer is mentioned. An example of the anisotropic scattering polarizer is DRP manufactured by 3M (see US Pat. No. 5,825,543).
Furthermore, there is a polarizing element that can perform polarization conversion in one pass. For example, the one using smectic C * can be mentioned (see JP 2001-201635 A). An anisotropic diffraction grating can be used.
The polarizing plate of the present invention can be used together with a brightness enhancement film. In the case of using a brightness enhancement film, it is more preferable that the polarizing plate and the brightness enhancement film are in close contact with each other in order to prevent moisture from entering the polarizing plate and suppress light leakage. The adhesive for bonding the polarizing plate and the brightness enhancement film is not particularly limited. For example, acrylic polymer, silicone polymer, polyester, polyurethane, polyamide, polyvinyl ether, vinyl acetate / vinyl chloride copolymer, modified polyolefin, epoxy-based, fluorine-based, natural rubber, synthetic rubber and other rubber-based polymers Can be appropriately selected and used. In particular, those excellent in optical transparency, exhibiting appropriate wettability, cohesiveness, and adhesive pressure-sensitive adhesive properties and excellent in weather resistance, heat resistance and the like can be preferably used.

<Touch panel>
The protective film of the present invention can be applied to touch panels described in JP-A-5-127822 and JP-A-2002-48913.

<Organic EL device>
The protective film of the present invention can be used as a substrate (transparent substrate film) such as an organic EL element or a protective film.
When the protective film of the present invention is used for an organic EL device or the like, JP-A Nos. 11-335661, 11-335368, 2001-192651, 2001-192651, 2001-192653, JP-A-2001-335776, JP-A-2001-247859, JP-A-2001-181616, JP-A-2001-181617, JP-A-2002-181816, JP-A-2002- The contents described in Japanese Patent No. 181617 and Japanese Patent Application Laid-Open No. 2002-056776 can be applied. Moreover, it is preferable to use together with the content of Unexamined-Japanese-Patent No. 2001-148291, Unexamined-Japanese-Patent No. 2001-221916, and Unexamined-Japanese-Patent No. 2001-231443.

  Hereinafter, the present invention will be described more specifically by way of examples. However, the embodiments of the present invention are not limited to these examples.

<Measurement method>
Hereinafter, a method for measuring various amounts described in this specification will be described.

[Moisture permeability]
The measurement method of moisture permeability is “Polymer Properties II” (Polymer Experiment Course 4, Kyoritsu Shuppan), pages 285-294: Measurement of vapor permeation (mass method, thermometer method, vapor pressure method, adsorption amount method) The method described in can be applied. In the present invention, the moisture content per unit area (g / m ² ) is determined in accordance with JIS Z-0208, except that the humidity control condition is changed to 60 ° C. and 95% RH, according to JIS Z-0208. Calculated. At this time, the operation of taking out and weighing the cup placed in the thermo-hygrostat at an appropriate time interval is repeated, and the mass increase per unit time is obtained for each of two consecutive weighings, and it is constant within 5%. Evaluation continued until.
Moreover, in order to exclude the influence by the moisture absorption etc. of a sample, the blank cup which does not put a hygroscopic agent was measured, and the value of moisture permeability was correct | amended.

[Haze]
The total haze, internal haze, and surface haze of the obtained film were measured by the following measurements.
1. The total haze value of the film obtained according to JIS-K7136 is measured.
2. A few drops of silicone oil were added to the front and back surfaces of the obtained film on the low refractive index layer side, and sandwiched from the front and back using two 1 mm thick glass plates (micro slide glass product number S 9111, manufactured by MATSANAMI), Two glass plates and the obtained film were optically adhered to each other, and the haze was measured in a state where surface haze was removed, and measurement was performed by sandwiching only silicone oil between two separately measured glass plates. The value obtained by subtracting haze was calculated as the internal haze of the film.
3. The value obtained by subtracting the internal haze calculated in 2 above from the total haze measured in 1 above was calculated as the surface haze of the film.

[Adhesion evaluation]
The adhesion between the film layers or between the support and the coating layer was evaluated by the following method.
Nitto Denko Co., Ltd. Polyester adhesive tape made by cutting a total of 100 square squares on the surface having the coating layer with a cutter knife in a grid pattern with 11 vertical and 11 horizontal cuts at 1 mm intervals. (NO.31B) or cello tape (registered trademark, NO.405) made by Nichiban Co., Ltd., and the test of peeling after leaving for 24 hours is repeated three times at the same place, and the presence or absence of peeling is visually observed. Evaluation was made based on the following evaluation criteria.

[Evaluation criteria]
◎: No peeling ○: The number of peeling is 5 or less △: The number of peeling is 30 or less, and there is no practical problem ×: There is peeling on the entire surface

[Light resistance]
In the present invention, as a light resistance test, a light resistance test apparatus (super xenon weather meter SX120 type (long life xenon lamp), manufactured by Suga Test Instruments Co., Ltd.) is used, and irradiance is 100 ± 25 W / m ² (wavelength Before and after the light resistance test 120 hr was performed according to JIS K 5600-7-5 under the conditions of 310 nm to 400 nm), test chamber temperature 35 ± 5 ° C., black panel temperature 50 ± 5 ° C., relative humidity 65 ± 15%. In addition, ΔE * ab was determined according to the above equation (1) using the L * value, a * value, and b * value calculated from the values measured using the spectrophotometer described above.

<Preparation of coating layer coating solution A-1>
The following composition was put into a mixing tank and stirred to dissolve each component to prepare a coating layer coating solution A-1.

[Composition of Coating Layer Coating Liquid A-1]
・ R204 10.0g
・ Tetrahydrofuran (stabilizer containing BHT 250PPM) 63.0g
・ MEK (methyl ethyl ketone) 13.5g
・ Toluene 13.5g
・ MXS-300 0.05g
・ 0.5g UV-2 (ultraviolet absorber) shown below

<Preparation of coating layer coating solution A-2>
Instead of adding MXS-300 in the preparation of coating solution A-1 for coating layer, coating was performed in the same manner as the coating solution A-1 for coating layer, except that 0.05 g of MX-180TA was added. Layer coating solution A-2 was prepared.

<Preparation of coating layer coating solution A-3>
A coating layer coating solution A-3 was prepared in the same manner as the coating layer coating solution A-1, except that the ultraviolet absorber UV-2 in the preparation of the coating layer coating solution A-1 was omitted. did.

<Preparation of Coating Layer Coating Liquid A-4>
The following composition was put into a mixing tank and stirred to dissolve each component to prepare a coating layer coating solution A-4.

[Composition of coating liquid A-4 for coating layer]
・ F216 9.62g
・ MiBK (methyl isobutyl ketone) 22.5 g
・ Cyclohexanone 2.5g
・ Silicia 0.03g
・ 0.1 g paraffin wax

<Preparation of coating layer coating solution A-5>
The following composition was put into a mixing tank and stirred to dissolve each component to prepare a coating layer coating solution A-5.

[Composition of coating liquid A-5 for coating layer]
・ HA-17F 9.62g
・ MiBK (methyl isobutyl ketone) 22.5 g
・ Cyclohexanone 2.5g
・ Silicia 0.03g
・ 0.1 g paraffin wax

<Preparation of coating layer coating solution A-6>
The following composition was put into a mixing tank and stirred to dissolve each component to prepare a coating layer coating solution A-6.

[Composition of coating liquid A-6 for coating layer]
・ Tricyclodecanediyl dimethacrylate 9.62g
・ MiBK (methyl isobutyl ketone) 22.5 g
・ Cyclohexanone 2.5g
・ Silicia 0.03g
・ 0.1 g paraffin wax

Here, the compounds used for the preparation of the coating layer coating solutions A-1 to A-6, respectively, are shown below.
R204: Vinylidene chloride copolymer [Asahi Kasei Life & Living Co., Ltd.]
F216: Vinylidene chloride copolymer [Asahi Kasei Life & Living Co., Ltd.]
HA-17F: Chlorinated vinyl chloride polymer [manufactured by Sekisui Chemical Co., Ltd.]
MXS-300: 3 μm cross-linked PMMA particle classification strengthened product [manufactured by Soken Chemical Co., Ltd.]
UV-2 / TINUVIN329: manufactured by Ciba Specialty Chemicals Co., Ltd. MX-180TA: 1.8 μm highly crosslinked PMMA particles [manufactured by Soken Chemical Co., Ltd.]
・ Silicia: Colloidal silica [Fuji Silysia Chemical Co., Ltd.]
・ Paraffin wax: [Nippon Seiki Co., Ltd.]

<Preparation of coating liquid B-1 for easy adhesion layer>
The following composition was put into a mixing tank and stirred to dissolve each component to prepare an easy-adhesion layer coating solution B-1.

[Composition of coating liquid B-1 for easy adhesion layer]
・ 44.7g of distilled water
・ L536B (49%) 3.6g
・ PVA124 1.8g

[Preparation of easy-adhesion layer coating solutions B-2 to B-5]
The easy adhesion is similar to the preparation of the easy adhesion layer coating liquid B-1, except that the addition amount of L536B and the addition amount of PVA124 in the easy adhesion layer coating liquid B-1 are changed as shown in Table 1. Layer coating solutions B-2 to B-5 were prepared.

<Preparation of coating liquid B-6 for easy adhesion layer>
The following composition was charged into a mixing tank and stirred to dissolve each component to prepare an easy-adhesion layer coating solution B-6.

[Composition of coating liquid B-6 for easy adhesion layer]
・ 44.7g of distilled water
・ L536B (49%) 3.6g
・ PVA117H 1.8g

<Preparation of coating liquid B-7 for easy adhesion layer>
The following composition was put into a mixing tank and stirred to dissolve each component to prepare an easy-adhesion layer coating solution B-7.

[Composition of Coating Solution B-7 for Easy Adhesive Layer]
・ 44.6g of distilled water
・ L549B (48%) 3.6g
・ PVA124 1.8g

<Preparation of coating liquid B-8 for easy adhesion layer>
The following composition was charged into a mixing tank and stirred to dissolve each component to prepare an easy-adhesion layer coating solution B-8.

[Composition of coating liquid B-8 for easy adhesion layer]
・ 823.0 g of distilled water
・ Latex A (28%) 151.5g
・ UFN1008 (10%) 0.5g

<Preparation of coating liquid B-9 for easy adhesion layer>
The following composition was put into a mixing tank and stirred to dissolve each component to prepare an easy-adhesion layer coating solution B-9.

[Composition of coating liquid B-9 for easy adhesion layer]
・ Distilled water 100.0g
・ PES-2405A30 (30%) 30.0g
・ Aquanate 100 2.10g

  In addition, about the said coating liquid B-1 to B-9 for easy-adhesion layers, it filtered with the filter made from a polypropylene with a hole diameter of 20 micrometers, and was set as coating liquid B-1 to B-9 for easy-adhesion layers.

Here, the compounds used in preparing the coating liquids B-1 to B-9 for the easy-adhesion layer are shown below.
L536B: Vinylidene chloride copolymer latex [Asahi Kasei Life & Living Co., Ltd.]
L549B: Vinylidene chloride copolymer latex [Asahi Kasei Life & Living Co., Ltd.]
PVA124: polyvinyl alcohol resin (saponification degree 98-99%, polymerization degree 2400) [manufactured by Kuraray Co., Ltd.]
PVA117H: polyvinyl alcohol resin (saponification degree of 99.3% or more, polymerization degree of 1700) [manufactured by Kuraray Co., Ltd.]
Latex A: Polymer latex solution of copolymer of methyl acrylate / methyl methacrylate = 70/30 (mass%) (glass transition temperature: 30 ° C., compound shown below: 2.5 mass% based on latex solids, Solid content concentration 28%, average particle size 120nm)
-PES-2405A30: Water-based polyester resin [manufactured by Toa Gosei Co., Ltd.]
・ Aquanate 100: Self-emulsifying polyisocyanate [Nippon Polyurethane Industry Co., Ltd.]

<Preparation of coating liquid for second coating layer>
The following composition was put into a mixing tank and stirred to dissolve each component to prepare a second coating layer coating solution C-1.

[Composition of Second Coating Layer Coating Liquid C-1]
・ Distilled water 100.0g
・ HR-3010 5.0g
・ ME-100 (5%) 10.0g

  ME-100 was mixed with water so as to have a desired concentration, and then subjected to high-pressure dispersion treatment at 30 MPa three times using a high-pressure disperser, and dispersed in water. HR-3010 was dissolved by stirring with distilled water at 95 ° C. for 2 hours. Then, both were mixed and the coating liquid of 2nd coating layer C-2 was produced.

[Composition of second coating layer coating solution C-2]
・ Distilled water 100.0g
・ PVA-117H 5.0g
・ ME-100 (5%) 10.0g

  ME-100 was mixed with water so as to have a desired concentration, and then subjected to high-pressure dispersion treatment at 30 MPa three times using a high-pressure disperser, and dispersed in water. HR-3010 was dissolved by stirring with distilled water at 95 ° C. for 2 hours. Then, both were mixed and the coating liquid of 2nd coating layer C-2 was produced.

[Composition of second coating layer coating solution C-3]
・ Distilled water 100.0g
・ L-101 5.0g

  In addition, about the said coating liquid C-1 to C-3 for 2nd coating layers, it filtered with the filter made from a polypropylene with a hole diameter of 40 micrometers, and was set as the coating liquids C-1 to C-3 for 2nd coating layers.

Here, the compounds used in preparing the second coating liquids C-1 to C-3 for the coating layer are shown below.
HR-3010: vinyl alcohol polymer [manufactured by Kuraray Co., Ltd.]
ME-100: Mica already dispersed under high pressure in water [Coop Chemical Co., Ltd.]
L-101: ethylene-vinyl alcohol copolymer [manufactured by Kuraray Co., Ltd.]

<Preparation of coating solution for hard coat layer>
[Preparation of Sol Solution 1]
In a 1,000 ml reaction vessel equipped with a thermometer, a nitrogen inlet tube and a dropping funnel, 187 g (0.80 mol) of acryloxyoxypropyltrimethoxysilane, 27.2 g (0.20 mol) of methyltrimethoxysilane, 320 g of methanol ( 10 mol) and 0.06 g (0.001 mol) of KF were added, and 15.1 g (0.86 mol) of water was slowly added dropwise at room temperature with stirring. After completion of the dropwise addition, the mixture was stirred at room temperature for 3 hours, and then heated and stirred for 2 hours under methanol reflux. Thereafter, low-boiling components were distilled off under reduced pressure, and further filtered to obtain 120 g of sol solution 1.
As a result of GPC measurement of the substance thus obtained, the mass average molecular weight was 1,500, and among the components higher than the oligomer component, the component having a molecular weight of 1,000 to 20,000 was 30%.
Moreover, from the measurement result of ¹ H-NMR, the structure of the obtained substance was a structure represented by the following general formula.

Furthermore, the condensation rate α as determined by ²⁹ Si-NMR was 0.56. From this analysis result, it was found that the silane coupling agent sol was mostly composed of a linear structure.
From the gas chromatography analysis, the raw material acryloxypropyltrimethoxysilane had a residual rate of 5% or less.

(1) Preparation of coating liquid for hard coat layer The following composition was put into a mixing tank and stirred to dissolve each component to prepare a coating liquid D-1 for hard coat layer.

[Composition of coating liquid D-1 for hard coat layer]
PET-30 40.0g
DPHA 10.0g
Irgacure 184 2.0g
SX-350 (30%) 2.0g
Cross-linked acrylic-styrene particles (30%) 13.0 g
FP-13 0.06g
Sol liquid a 11.0g
Toluene 38.5g

  The following composition was put into a mixing tank and stirred to dissolve each component to prepare a hard coat layer coating solution D-2.

[Composition of coating liquid D-2 for hard coat layer]
・ PET-30 28.0g
・ DPHA 12.0g
・ Cohesive silica (secondary aggregate diameter 1.5μm) 5.0g
・ Irgacure 184 1.0g
・ Irgacure 907 0.2g
・ FP-13 0.08g
・ Methyl isobutyl ketone 40.0g
・ Cyclohexanone 15.0g

  The following composition was put into a mixing tank and stirred to dissolve each component to prepare a hard coat layer coating solution D-3.

[Composition of coating liquid D-3 for hard coat layer]
・ PET-30 46.0g
・ Irgacure 184 1.7g
・ MX-600 (30%) 28.6g
・ FP-13 0.06g
・ Sol liquid 1 7.0g
・ MiBK (methyl isobutyl ketone) 13.0 g
・ MEK (methyl ethyl ketone) 6.0 g

  The following composition was put into a mixing tank and stirred to dissolve each component to prepare a hard coat layer coating solution D-4.

[Composition of Hard Coat Layer Coating Liquid D-4]
Desolite Z7404 100.0g
DPHA 31.0g
KBM-5103 10.0g
KEP-150 8.9g
MXS-300 3.4g
MEK 29.0g
MiBK 13.0g

  The following composition was put into a mixing tank and stirred to dissolve each component to prepare a hard coat layer coating solution D-5.

[Composition of coating liquid D-5 for hard coat layer]
CAP482-20 2.4g
Cyclomer P 13.4g
DPHA 16.3g
Irgacure 184 1.2g
MEK 51.0g
Butanol 14.0g
Propylene glycol monomethyl ether 3.5g

  The hard coat layer coating solutions D-1 to D-5 were filtered through a polypropylene filter having a pore size of 30 μm to obtain hard coat layer coating solutions D-1 to D-5.

Here, the compounds used in the preparation of the coating liquids D-1 to D-5 for the hard coat layer are shown below.
PET-30: A mixture of pentaerythritol triacrylate and pentaerythritol tetraacrylate [manufactured by Nippon Kayaku Co., Ltd.]
DPHA: Mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate [manufactured by Nippon Kayaku Co., Ltd.]
・ Irgacure 184: Polymerization initiator [Ciba Specialty Chemicals Co., Ltd.]
・ Irgacure 907: Polymerization initiator [Ciba Specialty Chemicals Co., Ltd.]
SX-350: average particle size 3.5 μm crosslinked polystyrene particles [refractive index 1.60, manufactured by Soken Chemical Co., Ltd., 30% toluene dispersion, used after dispersion for 20 minutes at 10,000 rpm with a Polytron disperser]
Crosslinked acrylic-styrene particles: average particle size 3.5 μm [refractive index 1.55, manufactured by Soken Chemical Co., Ltd., 30% toluene dispersion, used after dispersion for 20 minutes at 10,000 rpm with a Polytron disperser]
FP-13: fluorine-based surface modifier, compound shown below
MX-600: PMMA particles having an average particle size of 6 μm [refractive index: 1.49, manufactured by Soken Chemical Co., Ltd., 30% MIBK dispersion, used after dispersion at 10,000 rpm for 20 minutes in a Polytron disperser]
-Agglomerated silica: secondary agglomerated diameter 1.5 μm (primary particle size of several tens of nm), [manufactured by Nippon Silica Co., Ltd.]
Desolite Z7404: Photopolymerizable hard coat composition liquid containing zirconia fine particles [manufactured by JSR Corporation]
KBM-5103: γ-acryloyloxypropyltrimethoxysilane [manufactured by Shin-Etsu Chemical Co., Ltd.]
KE-P150: 1.5 μm silica particles [manufactured by Nippon Shokubai Co., Ltd.]
MXS-300: 3 μm cross-linked PMMA particles [manufactured by Soken Chemical Co., Ltd.]
CAP482-20: cellulose acetate propionate [manufactured by Eastman Chemical Co.]
・ Cyclomer P: Reactive oligomer [manufactured by Daicel UCB Co., Ltd.]

<Preparation of coating solution for low refractive index>
[Synthesis of Perfluoroolefin Copolymer (1)]
Into an autoclave with a stirrer made of stainless steel having an internal volume of 100 ml, 40 ml of ethyl acetate, 14.7 g of hydroxyethyl vinyl ether and 0.55 g of dilauroyl peroxide were charged, and the inside of the system was deaerated and replaced with nitrogen gas. Further, 25 g of hexafluoropropylene (HFP) was introduced into the autoclave and the temperature was raised to 65 ° C. The pressure when the temperature in the autoclave reached 65 ° C. was 0.53 Mpa (5.4 kg / cm ² ). The reaction was continued for 8 hours while maintaining the temperature, and when the pressure reached 0.31 MPa (3.2 kg / cm ² ), the heating was stopped and the mixture was allowed to cool. When the internal temperature dropped to room temperature, unreacted monomers were driven out, the autoclave was opened, and the reaction solution was taken out. The obtained reaction solution was poured into a large excess of hexane, and the polymer was precipitated by removing the solvent by decantation. Further, this polymer was dissolved in a small amount of ethyl acetate and reprecipitated twice from hexane to completely remove the residual monomer. After drying, 28 g of polymer was obtained. Next, 20 g of the polymer was dissolved in 100 ml of N, N-dimethylacetamide, and 11.4 g of acrylic acid chloride was added dropwise under ice cooling, followed by stirring at room temperature for 10 hours. Ethyl acetate was added to the reaction solution, washed with water, the organic layer was extracted and concentrated, and the resulting polymer was reprecipitated with hexane to obtain 19 g of perfluoroolefin copolymer (1) shown below. The resulting polymer had a refractive index of 1.421.

(Preparation of sol solution 2)
A stirrer, a reactor equipped with a reflux condenser, 120 parts by mass of methyl ethyl ketone, 100 parts by mass of acryloyloxypropyltrimethoxysilane (KBM-5103, manufactured by Shin-Etsu Chemical Co., Ltd.), 3 parts by mass of diisopropoxyaluminum ethyl acetoacetate After adding and mixing, 30 parts by mass of ion-exchanged water was added and reacted at 60 ° C. for 4 hours, and then cooled to room temperature to obtain sol solution 2. The mass average molecular weight was 1,600, and among the components higher than the oligomer component, the component having a molecular weight of 1,000 to 20,000 was 100%. Further, from the gas chromatography analysis, the raw material acryloyloxypropyltrimethoxysilane did not remain at all.

(Preparation of dispersion A)
Hollow silica fine particle sol (Isopropyl alcohol silica sol, average particle diameter 60 nm, shell thickness 10 nm, silica concentration 20 mass%, silica particle refractive index 1.31, size changed according to Preparation Example 4 of JP-A-2002-79616 Preparation) To 500 g, 30 g of acryloyloxypropyltrimethoxysilane (KBM-5103, manufactured by Shin-Etsu Chemical Co., Ltd.) and 1.5 g of diisopropoxyaluminum ethyl acetate were added and mixed, and then 9 g of ion-exchanged water was added.
Then, after making it react at 60 degreeC for 8 hours, it cooled to room temperature and added 1.8 g of acetylacetone.
While adding cyclohexanone to 500 g of this dispersion so that the silica content was almost constant, solvent substitution was performed by distillation under reduced pressure at a pressure of 20 kPa. No foreign matter was generated in the dispersion, and the viscosity when the solid content concentration was adjusted to 20% by mass with cyclohexanone was 5 mPa · s at 25 ° C. When the residual amount of isopropyl alcohol in the obtained dispersion A was analyzed by gas chromatography, it was 1.5%.

[Composition of coating liquid E-1 for low refractive index layer]
・ JTA113 (6%) 13.0 g
・ MEK-ST-L (30%) 1.3g
・ Sol solution 2 0.65g
・ MEK 4.4g
・ Cyclohexanone 1.2g

  The low refractive index layer coating liquid E-1 was prepared by filtering the low refractive index layer coating liquid E-1 through a polypropylene filter having a pore diameter of 1 μm. The refractive index of the low refractive index layer formed with this coating solution E-1 for low refractive index layer was 1.45.

[Composition of coating liquid E-2 for low refractive index layer]
・ JTA113 (6%) 783g
・ Dispersion A (20%) 195 g
・ MEK-ST-L (30%) 30g
・ Sol liquid 2 (29%) 17g
・ MEK 642g

  The low refractive index layer coating liquid E-2 was filtered through a polypropylene filter having a pore size of 5 μm to prepare a low refractive index layer coating liquid E-2. The refractive index of the low refractive index layer formed by this low refractive index layer coating solution E-2 was 1.39.

[Composition of coating liquid E-3 for low refractive index layer]
・ Perfluoroolefin copolymer (1) 15.4 g
・ Hollow silica fine particle sol (20%) 2.2g
・ X-22-164B 0.3g
-Sol liquid 2 (29%) 7.3 g
・ Irgacure 907 0.76g
・ MEK 298g
・ Cyclohexanone 12g

  The low refractive index layer coating liquid E-3 was filtered through a polypropylene filter having a pore size of 5 μm to prepare a low refractive index layer coating liquid E-3. The refractive index of the low refractive index layer formed with this coating solution E-3 for low refractive index layer was 1.40.

[Composition of coating liquid E-4 for low refractive index layer]
・ Ethylenically unsaturated group-containing fluoropolymer 45.0g
・ Dispersion A 195.0g
-Sol liquid 2 (29%) 17.0 g
・ PM980M 2.0g
・ MiBK 500g
・ MEK-ST-L (30%) 30g
・ MEK 55g

  The low refractive index layer coating liquid E-4 was prepared by filtering the low refractive index layer coating liquid E-4 through a polypropylene filter having a pore size of 5 μm. The refractive index of the low refractive index layer formed by this low refractive index layer coating solution E-4 was 1.38.

[Composition of coating liquid E-5 for low refractive index layer]
・ JTA105 (5%) 100g
・ JTA105A (5%) 1.0g
・ Butyl acetate 151.5g
・ Colcoat N103X (2%) 164g
・ Hollow silica fine particle sol (20%) 42.5g

  The low refractive index layer coating liquid E-5 was filtered through a polypropylene filter having a pore size of 5 μm to prepare a low refractive index layer coating liquid E-5. The refractive index of the low refractive index layer formed with this coating solution E-5 for low refractive index layer was 1.36.

The compounds used in the coating solutions E-1 to E-5 for the low refractive index layer are shown below.
JTA113: heat-crosslinkable fluorine-containing polymer having a refractive index of 1.44 containing polysiloxane and hydroxyl group [manufactured by JSR Corporation]
MEK-ST-L: colloidal silica dispersion [average particle size 45 nm, manufactured by Nissan Chemical Co., Ltd.]
X-22-164B: reactive silicone [manufactured by Shin-Etsu Chemical Co., Ltd.]
Ethylenically unsaturated group-containing fluoropolymer: fluoropolymer (A-1) described in Production Example 3 of JP-A-2005-89536
PM980M: polymerization initiator [Wako Pure Chemical Industries, Ltd.]
JTA105: Fluorine compound having a fluoroalkyl group and a polysiloxane structure [manufactured by JSR Corporation]
・ Opta-JTA105A: [manufactured by JSR Corporation]
Colcoat N103X: siloxane oligomer (number average molecular weight 950 in terms of ethylene glycol) [manufactured by Colcoat Co., Ltd.]

Example 1
<Preparation of protective film for polarizing plate>
<Coating of the first coating layer>
80 μm thick triacetyl cellulose film (TAC-TD80U, manufactured by FUJIFILM Corporation) is unwound in the form of a roll, and is coated with a slot die to form a first coating layer A- The coating solution A-1 was applied onto the cellulose acylate film 1 so that the thickness of 1 was 2 μm, applied on the condition of a conveyance speed of 30 m / min, dried at 100 ° C. for 2 minutes and wound up.
Further, the easy-adhesion layer coating solution b-1 is applied on the application surface of the first coating layer A-1 so that the thickness of the easy-adhesion layer B-1 formed after drying is 0.5 μm. , Dried at 100 ° C. for 2 minutes and wound up.
Then, the coating liquid C-1 is applied on the easy-adhesion layer B-1 so that the thickness of the second coating layer C-1 formed after drying is 7 μm, and dried at 100 ° C. for 3 minutes. Winded up.

<Coating of hard coat layer>
An 80 μm-thick triacetyl cellulose film (TAC-TD80U, FUJIFILM Corporation) with the first coating layer A-1 and the second coating layer C-2 applied thereto via the easy adhesion layer B-1 Co., Ltd.) was unrolled in the form of a roll, and using a coater having a slot die, the coating liquid D-1 for hard coat layer was coated with the first coating layer A-1 on the triacetyl cellulose film. It was extruded and applied directly to the surface opposite to the side.
This hard coat layer coating solution D-1 was applied under the condition of a conveyance speed of 30 m / min, dried at 30 ° C. for 15 seconds and 90 ° C. for 20 seconds, and then air-cooled metal halide lamp (160 W / cm under nitrogen purge) Using an iGraphics Co., Ltd.), the coating layer is cured by irradiating with an ultraviolet ray with an irradiation amount of 90 mJ / cm ² to form an antiglare hard coat layer D-1 having a thickness of 6 μm, Winded up.

<Coating of low refractive index layer>
The first coating layer A-1 and the second coating layer C-1 are coated on one surface and the hard coat layer D-1 is coated on the other surface via the easy adhesion layer B-1. The 80 μm-thick triacetyl cellulose film (TAC-TD80U, manufactured by Fuji Film Co., Ltd.) was unwound in a roll form, and a polarizing plate protective film on a backup roll was used by using a coater having a slot die. On the surface to which the hard coat layer D-1 is applied, the low refractive index layer coating solution E-1 is directly extruded and applied to form a low refractive index layer E-1 having a thickness of 100 nm, and wound. The protective film 1 for polarizing plates in which the two coating layers A-1, C-1, the hard coat layer D-1, and the low refractive index layer E-1 were formed was produced. The drying / curing conditions are shown below.
Drying: Dried at 90 ° C. for 60 seconds.
Curing: After curing at 110 ° C. for 10 minutes, using a 240 W / cm air-cooled metal halide lamp (manufactured by Igraphic Co., Ltd.) in an atmosphere with an oxygen concentration of 0.1% by nitrogen purge, the irradiation dose is 400 mJ / cm ² . Irradiated with ultraviolet rays.

(Examples 3-6 and 9-30)
<Preparation of protective film for polarizing plate>
The protective films for polarizing plates of Examples 3-6 and 9-30 were prepared in the same manner as in Example 1 except that the presence / absence of each layer, the type of coating solution, and the film thickness were changed as shown in Table 2.
Moreover, it carried out similarly to Example 1, and evaluated the protective film for polarizing plates of Examples 3-6 and 9-30. The evaluation results are shown in Table 3.

(Examples 2, 7 and 8)
Subsequent to the first coating layer A-1 or A-4, a hard coat layer coating solution and a low refractive index layer coating solution are applied to the same side on which the easy adhesion layer is coated as shown in Table 2. Thus, protective films for polarizing plates of Examples 2, 7 and 8 were produced.
Moreover, it carried out similarly to Example 1, and evaluated the protective film for polarizing plates of Example 2, 7 and 8. The evaluation results are shown in Table 3.

(Example 11)
A protective film for a polarizing plate of Example 11 was produced in the same manner as in Example 1 as shown in Table 2, except that a polyester film “Lumirror # 25” (manufactured by Toray Industries, Inc.) was used instead of TAC-TD80U. did.
Moreover, it carried out similarly to Example 1, and evaluated the protective film for polarizing plates of Example 11. FIG. The evaluation results are shown in Table 3.

(Example 14)
A protective film for a polarizing plate of Example 14 was produced in the same manner as in Example 1 as shown in Table 2, except that a 20 μm thick triacetylcellulose film was used instead of TAC-TD80U.
Moreover, it carried out similarly to Example 1, and evaluated the protective film for polarizing plates of Example 14. FIG. The evaluation results are shown in Table 3.

(Examples 25, 27 and 30)
<Preparation of protective film for polarizing plate)
The protective film for polarizing plates of Examples 25, 27 and 30 in the same manner as in Example 1 except that the coating liquid for hard coat layer and the coating liquid for low refractive index layer in Example 1 were changed as shown in Table 2. Was made. At that time, the drying / curing conditions were changed as shown below.
Drying: Dried at 90 ° C. for 60 seconds.
Curing: Irradiation with ultraviolet rays with an irradiation amount of 400 mJ / cm ² was performed using a 240 W / cm air-cooled metal halide lamp (manufactured by Eyegraphic Co., Ltd.) in an atmosphere with an oxygen concentration of 0.1% by nitrogen purge.
Moreover, it carried out similarly to Example 1, and evaluated the protective film for polarizing plates of Example 25, 27, and 30. FIG. The evaluation results are shown in Table 3.

(Comparative Example 1)
<Preparation of protective film for polarizing plate>
A polarizing plate protective film of Comparative Example 1 was prepared in the same manner as in Example 1 except that the presence / absence of each layer, the type of coating solution, and the film thickness were changed as shown in Table 2.
Moreover, it carried out similarly to Example 1, and evaluated the protective film for polarizing plates. The evaluation results are shown in Table 3.

(Comparative Example 2)
<Preparation of protective film for polarizing plate>
A polarizing plate protective film of Comparative Example 2 was produced in the same manner as in Example 2 except that the presence / absence of each layer, the type of coating solution, and the film thickness were changed as shown in Table 2.
Moreover, it carried out similarly to Example 2, and evaluated the protective film for polarizing plates. The evaluation results are shown in Table 3.

As shown in Table 3, the protective films for polarizing plates of Examples 1 to 30 showed good results in adhesion and light resistance. In particular, better results were obtained in Example 1, Example 12, and Example 14.
On the other hand, the protective films for polarizing plates of Comparative Examples 1 and 2 were remarkably poor in adhesion or light resistance and were inappropriate as products.

(Example 31) Polarizing plate WV
<Production of polarizer>
A 120 μm-thick polyvinyl alcohol film was immersed in an aqueous solution containing 1 part by mass of iodine, 2 parts by mass of potassium iodide, and 4 parts by mass of boric acid, and stretched 4 times at 50 ° C. to produce a polarizer.

<Saponification of second protective film>
A WV film (manufactured by FUJIFILM Corporation) as a second protective film coated with an optically anisotropic layer was immersed in a 1.5 mol / L sodium hydroxide aqueous solution at 55 ° C. for 120 seconds, and then washed with water. Dried.

<Preparation of polarizing plate>
Using the protective film for polarizing plate of Example 1 as the first protective film, the surface on which the second coating layer is applied and the surface on which the optically anisotropic layer of the second protective film is not applied, The polarizing plate of Example 31 was produced by laminating the above polarizer using a completely saponified polyvinyl alcohol 5% aqueous solution as an adhesive.

<Evaluation of polarizing plate>
[Degree of polarization]
The polarizing plate obtained as described above was allowed to stand for 1000 hours in an environment of 60 ° C. and 95% RH, and then the degree of polarization was measured. The degree of polarization is obtained from the following mathematical formula (3). (Wavelength 550nm)

Evaluation of degree of polarization ○: There is no problem when the degree of polarization is 99% or more.
Δ: The degree of polarization is 98% or more and less than 99%, and there is no practical problem.
X: The degree of polarization is less than 98%, which is a problem.

[Coloring]
The protective film for polarizing plates was visually observed to determine the degree of coloring (yellowing).
○: Level with almost no coloring.
Δ: Level that is very lightly colored but has no problem in practice ×: Level that coloring is a problem

(Examples 32 to 60)
<Preparation of polarizing plate>
Polarizing plates of Examples 32 to 60 were produced in the same manner as in Example 31 except that the first protective film in Example 31 was changed as shown in Table 4.
Moreover, it carried out similarly to Example 31, and evaluated the polarizing plate of Examples 32-60. The evaluation results are shown in Table 4.

(Example 61) Polarizing plate T
<Preparation of polarizing plate>
A polarizing plate of Example 61 was produced in the same manner as in Example 31 except that the second protective film (WV film) in Example 31 was ordinary TAC (TD80 manufactured by FUJIFILM Corporation).
Further, the polarizing plate of Example 61 was evaluated in the same manner as Example 31. The evaluation results are shown in Table 4.

(Example 62) Polarizing plate Z
<Preparation of polarizing plate>
Except that the second protective film (WV film) in Example 31 was low retardation TAC (manufactured by Z-TAC FUJIFILM Corporation. Re = 1 nm, Rth = -3 nm), it was the same as Example 31. A polarizing plate of Example 62 was produced.
Further, the polarizing plate of Example 62 was evaluated in the same manner as Example 31. The evaluation results are shown in Table 4.

(Comparative Examples 3-6)
<Preparation of polarizing plate>
Polarizing plates of Comparative Examples 3 to 6 were produced in the same manner as in Example 31 except that the first protective film in Example 31 was changed as shown in Table 4.
Moreover, it carried out similarly to Example 31, and evaluated the polarizing plate of Comparative Examples 3-6. The evaluation results are shown in Table 4.

As shown in Table 4, in the polarizing plates of Examples 31 to 62, there is no problem of degree of polarization and coloring, peeling of the protective film does not occur even in long-term use, and preferable performance for use in a liquid crystal display device or the like. Since it showed, the display image quality of displays, such as a liquid crystal display device, can be maintained high quality over a long period of time.
On the other hand, in the polarizing plates of Comparative Examples 3 and 4, the degree of polarization or coloring was remarkably poor, and in Comparative Example 3, the protective film was peeled off.

(Example 63)
<Production of liquid crystal display device>
<< Production of TN liquid crystal display device >>
The polarizing plate provided in the liquid crystal display device (MDT-191S, manufactured by Mitsubishi Electric Corporation) using a TN type liquid crystal cell is peeled off, and the polarizing plate of Example 31 is replaced with the hard coat layer and the low refractive index instead. The liquid crystal display of Example 63 was pasted with an adhesive so that the surface on which the layer was applied was on the outside (viewing side) and the transmission axis of the polarizing plate coincided with the polarizing plate attached to the product. A device was made.

<Evaluation of light leakage after high and low humidity treatment (peripheral unevenness evaluation)>
After the liquid crystal display device is treated at 60 ° C., 90%, 50 hours, and 70 ° C., 10%, 50 hours, and left in an environment of 25 ° C., 60% for 2 hours, the liquid crystal display device displays black in a dark room. The light leakage from the front was visually observed by a plurality of observers and evaluated based on the following evaluation criteria. The evaluation results are shown in Table 5.

[Evaluation criteria]
○: No light leakage was observed. Δ: Light leakage was present at a satisfactory level. ×: Light leakage was clearly observed.

(Examples 64-92)
<Production of liquid crystal display device>
Liquid crystal display devices of Examples 64-92 were produced in the same manner as in Example 63 except that the first polarizing plate in Example 63 was changed as shown in Table 5.
Further, the liquid crystal display devices of Examples 64-92 were evaluated in the same manner as Example 63. The evaluation results are shown in Table 5.

(Comparative Examples 5 and 6)
<Production of liquid crystal display device>
Liquid crystal display devices of Comparative Examples 5 and 6 were produced in the same manner as in Example 63 except that the first polarizing plate in Example 63 was changed as shown in Table 5.
Further, in the same manner as in Example 63, the liquid crystal display devices of Comparative Examples 5 and 6 were evaluated. The evaluation results are shown in Table 5.

(Example 93)
<Production of VA liquid crystal display device>
The polarizing plate provided in the VA liquid crystal display device (LC-26GD3 manufactured by Sharp) was peeled off while leaving the retardation film on the liquid crystal cell side, and the polarizing plate of Example 61 was replaced with the transmission axis of the polarizing plate instead. Was attached to match the polarizing plate attached to the product, and a liquid crystal display device of Example 93 was produced. The polarizing plate of Example 61 was pasted so that the surface on which the hard coat layer and the low refractive index layer were applied was on the outside.

(Comparative Example 9)
A liquid crystal display device of Comparative Example 9 was produced in the same manner as in Example 93 except that the polarizing plate of Example 61 in Example 93 was changed to the polarizing plate of Comparative Example 5 as shown in Table 5.
Further, the liquid crystal display device of Comparative Example 9 was evaluated in the same manner as in Example 93. The evaluation results are shown in Table 5.

(Example 94)
<Production of IPS liquid crystal display device>
The polarizing plate provided in the IPS type liquid crystal display device (TH-26LX300, manufactured by Matsushita) is peeled off, and instead the polarizing plate of Example 62 matches the polarizing plate with the transmission axis of the polarizing plate attached to the product. Thus, a liquid crystal display device of Example 94 was produced. The polarizing plate of Example 62 was attached so that the surface on which the hard coat layer and the low refractive index layer were applied was on the outside.

(Comparative Example 10)
A liquid crystal display device of Comparative Example 10 was produced in the same manner as in Example 94 except that the polarizing plate of Example 62 in Example 94 was changed to the polarizing plate of Comparative Example 6 as shown in Table 5.
Further, in the same manner as in Example 94, the liquid crystal display device of Comparative Example 10 was evaluated. The evaluation results are shown in Table 5.

(Example 95)
In addition, the polarizing plate provided in the IPS liquid crystal display device (32LC100 manufactured by Toshiba) leaves the retardation film on the front side, peels off the retardation film on the back side, and instead uses the polarizing plate of Example 63 of the polarizing plate. The liquid crystal display device of Example 95 was manufactured by pasting so that the transmission axis coincided with the polarizing plate pasted on the product. The polarizing plate of Example 63 was attached so that the surface on which the hard coat layer and the low refractive index layer were applied was on the outside.

(Comparative Example 11)
A liquid crystal display device of Comparative Example 11 was produced in the same manner as in Example 95 except that the polarizing plate of Example 63 in Example 95 was changed to the polarizing plate of Comparative Example 6 as shown in Table 5.
Further, in the same manner as in Example 95, the liquid crystal display device of Comparative Example 11 was evaluated. The evaluation results are shown in Table 5.

As shown in Table 5, in the liquid crystal display devices of Examples 63 to 95, there is no problem of peripheral unevenness under high temperature and high humidity environment, and the protective film does not peel off even after long-term use. Quality can be kept high for a long time.
On the other hand, in the liquid crystal display devices of Comparative Examples 7 to 11, the peripheral unevenness was extremely bad, and Comparative Example 7 was a problem because the protective film was peeled off.

  Instead of the TAC-TD80U used in the above examples as a transparent substrate film, a polarizing plate protective film, a polarizing plate, and a polarizing plate were prepared in the same manner as in the above examples except that a cellulose acylate film prepared as described below was used. As a result of creating and evaluating the image display device, the polarizing plate durability was further improved without affecting other performances.

<Preparation of cellulose acylate solution>
The following composition was put into a mixing tank and stirred to dissolve each component to prepare a cellulose acylate solution A.

[Composition of Cellulose Acylate Solution A]
Cellulose triacetate (acetyl substitution degree 2.86) 100.0 parts by mass Triphenyl phosphate (plasticizer 1) 6.0 parts by mass Biphenyl phosphate (plasticizer 2) 3.0 parts by mass Methylene chloride 1 solvent) 402.0 parts by mass
・ Methanol (second solvent) 60.0 parts by mass

<Preparation of matting agent solution>
The following composition was put into a disperser and stirred to dissolve each component to prepare a matting agent solution A.

[Composition of matting agent solution A]
Silica particles having an average particle diameter of 16 nm (AEROSIL R972, manufactured by Nippon Aerosil Co., Ltd. 2.2 parts by mass) Cellulose triacetate (acetyl substitution degree 2.88) 2.0 parts by mass Triphenyl phosphate (plasticizer 1) 0 .2 parts by mass-biphenyl phosphate (plasticizer 2) 0.1 parts by mass-methylene chloride (first solvent) 83.5 parts by mass
・ Methanol (second solvent) 12.0 parts by mass

<Preparation of UV absorber solution A>
The following composition was put into a mixing tank, stirred while heating to dissolve each component, and an ultraviolet absorbent solution A was prepared.

[Composition of UV absorber solution A]
-UV-1 (ultraviolet absorber) shown below 3.0 parts by mass-UV-10 (ultraviolet absorber) shown below 12.0 parts by mass-Cellulose triacetate (acetyl substitution degree 2.86) 4.4 parts by mass・ Triphenyl phosphate (plasticizer 1) 0.4 parts by mass ・ Biphenyl phosphate (plasticizer 2) 0.2 parts by mass ・ Methylene chloride (first solvent) 70.0 parts by mass
・ Methanol (second solvent) 10.0 parts by mass

(Preparation of cellulose acylate film 1)
97.4 parts by mass of cellulose acylate solution A, 1.3 parts by mass of matting agent solution A and 1.3 parts by mass of ultraviolet absorber solution A were mixed after filtration, and cast using a band casting machine. When the residual solvent was 60%, the film was peeled off from the band, and the film was held at 100 ° C. using a clip tenter and held at 130 ° C. for 30 seconds with the width after 5% stretching. Thereafter, the clip was removed and dried at 130 ° C. for 40 minutes to produce a cellulose acylate film 1 as a transparent substrate film.
The obtained cellulose acylate film 1 had a residual solvent amount of 0.2% by volume and a film thickness of 80 μm.

Since the protective film of the present invention has high adhesion due to changes in heat and humidity, and has high durability and good haze, it can be suitably used for polarizing plates and liquid crystal display devices using the same. .
Since the polarizing plate of the present invention has high adhesion due to changes in heat and humidity, and has high durability and good haze, it can be suitably used for a liquid crystal display device.
The liquid crystal display device of the present invention is excellent in productivity, suppressed unevenness due to light leakage, and has excellent performance of light leakage in high temperature and high humidity environmental changes, such as mobile phones, monitors for personal computers, televisions, It is suitably used for a liquid crystal projector or the like.

FIG. 1 is a cross-sectional view schematically showing a preferred embodiment of the protective film for polarizing plate of the present invention. FIG. 2 is a cross-sectional view schematically showing a preferred embodiment of the polarizing plate of the present invention. FIG. 3 is a sectional view schematically showing a preferred embodiment of the image display device of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Polarizing plate 10 1st protective film 11 Transparent base film 12 Cover layer 12a 1st cover layer 12b 2nd cover layer 13 Easy adhesion layer 20 2nd protective film 21 Transparent base film 22 Optically anisotropic layer 30 Polarizer 40 Hard coat layer 50 Undercoat layer 100 Liquid crystal display device 101 Liquid crystal cell

Claims (18)

  On one surface of the transparent base film, a coating layer is formed by laminating at least one or more of the first coating layer exhibiting hydrophobicity and the second coating layer exhibiting hydrophilicity, An easy-adhesion layer showing an I / O value between the I / O value of the coating layer and the I / O value of the second coating layer is between the first coating layer and the second coating layer. A protective film for a polarizing plate, comprising at least one layer.   The protective film for polarizing plates according to claim 1, wherein the difference between the I / O value of the first coating layer and the I / O value of the second coating layer is 0.5 or more.   The difference between the I / O value of the first coating layer and the I / O value of the second coating layer and the I / O value of the easy-adhesion layer is 0.1 or more. The protective film for polarizing plates as described in 2.   The protective film for polarizing plates according to any one of claims 1 to 3, wherein the easy-adhesion layer has a refractive index between the refractive index of the first coating layer and the refractive index of the second coating layer.   The protective film for polarizing plates according to any one of claims 1 to 4, wherein the easy adhesion layer contains a compound contained in each of the first coating layer and the second coating layer.   The protective film for polarizing plates according to claim 1, wherein the second coating layer is provided on the outermost layer.   The protective film for polarizing plates according to any one of claims 1 to 6, wherein at least one layer of the second coating layer contains a hydrophilic polymer compound.   The protective film for polarizing plates according to claim 7, wherein the hydrophilic polymer compound is polyvinyl alcohol.   The protective film for polarizing plates according to any one of claims 1 to 8, wherein at least one of the first coating layers has a polymer containing a repeating unit derived from a chlorine-containing vinyl monomer.   The protective film for polarizing plates according to claim 9, wherein the chlorine-containing vinyl monomer is vinylidene chloride.   The polarized light according to any one of claims 1 to 10, wherein the transparent substrate film contains cellulose acylates, and the cellulose acylates are cellulose acetate, cellulose acetate propionate, or cellulose acetate butyrate. Board protective film.   The protective film for a polarizing plate according to any one of claims 1 to 11, wherein the easily adhesive layer has a thickness of 0.05 µm or more and 5 µm or less.   13. The protective film for a polarizing plate according to claim 1, wherein the coating layer has a thickness of 0.05 μm or more and 10 μm or less.   The protective film for polarizing plates according to any one of claims 1 to 13, wherein the transparent substrate film has a thickness of 30 to 120 µm.   It includes a step of preparing an easy-adhesion layer coating solution, which is hydrophobic and has an aqueous dispersion of components derived from the compound contained in the first coating layer, and prepares an easy-adhesion layer coating solution using a solvent as water. The manufacturing method of the protective film for polarizing plates to perform.   A first coating layer coating solution preparing step of preparing a first coating layer coating solution for forming a first coating layer using a solvent as a solvent; and a second coating layer forming a second coating layer using water as a solvent. The manufacturing method of the protective film for polarizing plates of Claim 15 including the coating liquid preparation process for the 2nd coating layer which prepares the coating liquid for coating layers.   A polarizing plate comprising the polarizing plate protective film according to claim 1 and a polarizer.   A liquid crystal display device comprising the polarizing plate according to claim 17 and a liquid crystal cell.