JP2014095730A - Optical film and method for producing the same, polarizing plate and liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical film and a production method of the film capable of reducing curling of the film, and to provide a liquid crystal display device capable of suppressing the generation of black display irregularity after the device is exposed to a high temperature and high humidity environment.SOLUTION: The optical film includes a base film essentially comprising a (meth)acryl polymer and a low moisture permeable layer laminated on the base film; and a production method of the film and a liquid crystal display device using the film are also disclosed. The optical film shows a moisture permeability of 100 g/m/day or less and satisfies expression (1):0.01≤A/B≤0.8. In expression (1), A represents a moisture permeability of the optical film comprising the base film and the low moisture permeable layer laminated thereon; and B represents a moisture permeability of the base film. The moisture permeability is measured according to the procedure of JIS 0208 after the film is kept at 40°C and 90% relative humidity for 24 hours.

Description

  The present invention relates to an optical film, a method for producing the same, a polarizing plate, and a liquid crystal display device.

  In recent years, liquid crystal display devices have been widely used for liquid crystal panels such as liquid crystal televisions, personal computers, mobile phones, and digital cameras. Usually, a liquid crystal display device has a liquid crystal panel member provided with polarizing plates on both sides of a liquid crystal cell, and display is performed by controlling light from the backlight member with the liquid crystal panel member. Here, the polarizing plate is composed of a polarizer and protective films on both sides thereof, and a general polarizer is obtained by dyeing a stretched polyvinyl alcohol (PVA) film with iodine or a dichroic dye to protect it. A cellulose ester film or the like is used as the film.

Recent liquid crystal display devices are becoming more and more demanding, and the demands for durability are becoming stricter as the quality of the liquid crystal display devices increases. For example, when used in outdoor applications, stability against environmental changes is required, and optical films such as the above-described polarizing plate protective film and optical compensation film used in liquid crystal display devices also have dimensions and optical characteristics with respect to temperature and humidity changes. It is required to suppress changes in
Problems with liquid crystal display devices exposed to high temperature and high humidity include the occurrence of warpage and display unevenness in the liquid crystal cell of the liquid crystal display device. This is a problem with polarizing plates and optical films that compose them, particularly polarizers. When moisture absorbs and desorbs, a contraction difference occurs between the front and back polarizing plates of the liquid crystal cell of the liquid crystal display device, the balance is lost, the liquid crystal cell warps, and the four corners and four sides of the liquid crystal cell are members on the housing and the back side. This is considered to be caused by display unevenness caused by contact with the. For this reason, improvements in humidity dependency and wet heat durability have been required for protective films for polarizing plates, but for drastic improvement, it is necessary to suppress moisture absorption and desorption due to environmental changes. In particular, the optical film on the outermost surface of the polarizing plate is required to have a performance that prevents moisture from passing through, that is, a reduction in moisture permeability.

Patent Document 1 describes an optical device in which a large amount of acrylic resin such as polymethyl methacrylate (PMMA) is added to cellulose ester for the purpose of providing an optical film having high transparency, low moisture absorption, high heat resistance, and high mechanical strength. A film is disclosed.
On the other hand, a film in which a low moisture permeability layer is provided on a base film is also known. For example, Patent Document 2 discloses a composition having a compound having a cyclic aliphatic hydrocarbon group and two or more unsaturated double bond groups in the molecule on a base film made of cellulose acylate having a film thickness of 80 μm. Although a film provided with a low moisture permeability layer formed from is described, sufficient low moisture permeability was not obtained.

International Publication No. 2009/047924 JP 2006-83225 A

  Liquid crystal display devices are used not only in conventional indoor applications but also in harsher environments such as outdoors, and for the optical film on the outermost surface of the liquid crystal display device, it is important to have a performance that does not transmit moisture. . In TV applications that are becoming larger in size in recent years, this problem is also affected by the tendency of the glass of the liquid crystal cell to become thinner, warping tends to increase, and there is concern about the effects on black display unevenness after aging in a high temperature and high humidity environment. . In addition, since small and medium-sized devices such as tablet PCs and mobile applications, which have been rapidly spreading in recent years, have high demands for thinning and space-saving in liquid crystal display devices, it is strongly desired to solve the problem of black display unevenness after aging in a high-temperature and high-humidity environment. .

In view of the above situation, an object of the present invention, that is, a problem to be solved by the present invention is to provide an optical film capable of reducing moisture permeation and a method for producing the same.
Furthermore, the problem to be solved by the present invention is to provide an optical film capable of reducing the curl of the film found by reexamining Patent Document 2 and a method for producing the same.
Another object of the present invention is to provide a polarizing plate using the optical film. Still another object of the present invention is to provide a liquid crystal display device in which unevenness in black display after a high temperature and high humidity environment is improved.
In particular, it has not been known that there is a correlation between an optical film and a curl value.

As a result of intensive studies by the present inventors, it is possible to provide an optical film capable of reducing moisture permeation, and further, by using such an optical film as a protective film for a polarizing plate, black display after aging at a high temperature and high humidity environment The present inventors have found that a liquid crystal display device with improved unevenness can be provided, and have reached the present invention.
The problem to be solved by the present invention can be solved by the present invention which is the following means.

[1]
An optical film having a base film mainly composed of a (meth) acrylic polymer and a low moisture permeable layer laminated on the described film,
The optical film has a moisture permeability of 100 g / m ² / day or less,
An optical film characterized by satisfying the following formula (1).
Formula (1) 0.01 <= A / B <= 0.8
(In Formula (1), A represents the water vapor transmission rate of the optical film which laminated | stacked the said low moisture-permeable layer on the said base film, B represents the water vapor transmission rate of the said base film. However, a water vapor transmission rate is JIS 0208. (This is the value after 24 hours at 40 ° C. and 90% relative humidity.)
[2]
Moisture permeability of the low moisture permeable layer when the thickness of the low moisture permeable layer is 10 μm J _b × d _b / 10
Is 5.0 to 250 g / m ² / day, the optical film as described in [1] above.
(Here, d _b [μm] represents the film thickness of the low moisture-permeable layer, and is calculated from the film thickness difference before and after the lamination of the low moisture-permeable layer.
Further, J _b represents the moisture permeability of the low moisture-permeable layer when separating the optical film to the substrate and the low moisture-permeable layer, the moisture permeability J _s of the moisture permeability J _f, the substrate film of the optical _film, low the moisture permeability of the moisture-permeable layer is calculated from the following equation when a J _b. )
1 / J _f = 1 / J _s + 1 / J _b Expression (n)
[3]
In the above [1] or [2], the (meth) acrylic polymer is a polymer having any of a lactone ring structure, a glutaric anhydride ring structure, and a glutarimide ring structure in the main chain. The optical film as described.
[4]
The optical film as described in [3] above, wherein the (meth) acrylic polymer is a polymer having a unit represented by the following general formula (1).
General formula (1):

(Wherein R ¹¹ , R ¹² and R ¹³ each independently represents a hydrogen atom or an organic residue having 1 to 20 carbon atoms. The organic residue may contain an oxygen atom.)
[5]
The film thickness of the said base film is 5-80 micrometers, The optical film as described in any one of said [1]-[4] characterized by the above-mentioned.
[6]
The optical film according to any one of [1] to [5], wherein the low moisture-permeable layer has a thickness of 1 to 12 μm.
[7]
The low moisture permeation layer is a layer formed from a low moisture permeation forming composition having a compound having a cyclic aliphatic hydrocarbon group and an unsaturated double bond group in the molecule. The optical film according to any one of [1] to [6].
[8]
The low moisture-permeable layer is composed of a compound having a cyclic aliphatic hydrocarbon group and an unsaturated double bond group in the molecule with respect to the total solid content excluding inorganic components in the composition for forming a low moisture-permeable layer. The optical film as described in [7] above, which is a layer formed from a composition containing ~ 99% by mass.
[9]
The said optical film has a hard-coat layer further, The optical film as described in any one of said [1]-[8] characterized by the above-mentioned.
[10]
The hard coat layer is a layer formed from a composition for forming a hard coat layer having a compound having a cyclic aliphatic hydrocarbon group and two or more unsaturated double bond groups in the molecule. The optical film according to any one of [1] to [9] above.
[11]
The optical film as described in [10] above, wherein the composition for forming a hard coat layer further contains a (meth) acrylate having 5 or more functional groups.
[12]
[1] to [1], wherein the low moisture permeability layer is a layer formed from a composition for low moisture permeability formation having a compound having a fluorene skeleton and an unsaturated double bond group in the molecule. [6] The optical film according to any one of [6].
[13]
The low moisture-permeable layer is a compound having a fluorene skeleton and an unsaturated double bond group in the molecule, based on the total solid content excluding the inorganic components in the composition for forming the low moisture-permeable layer, 60 to 99% by mass. The optical film as described in [12] above, which is a layer formed from a composition containing the optical film.
[14]
The optical film according to any one of the above [1] to [13], wherein the base film is formed by melting a thermoplastic resin mainly composed of a (meth) acrylic polymer. the film.
[15]
A step of melt-forming a base film mainly composed of a (meth) acrylic polymer; and
The manufacturing method of the optical film which has a low moisture-permeable layer laminated | stacked on the base film including the process of laminating | stacking a low moisture-permeable layer on the said base film by application | coating.
[16]
A polarizer,
A polarizing plate comprising at least one optical film according to any one of [1] to [14] as a protective film for the polarizer.
[17]
A liquid crystal cell;
Including the polarizing plate according to the above [16] disposed in at least one of the liquid crystal cells,
A liquid crystal display device, wherein the optical film is arranged to be an outermost layer.

  According to the present invention, an optical film capable of reducing moisture permeation and a method for producing the same can be provided. By using the optical film of the present invention, it is possible to provide a liquid crystal display device in which the occurrence of black display unevenness after a high temperature and high humidity environment has been suppressed.

Below, the polarizing plate of this invention, its manufacturing method, the additive used for it, etc. are demonstrated in detail.
The description of the constituent elements described below may be made based on typical embodiments of the present invention, but the present invention is not limited to such embodiments. In the present specification, a numerical range represented by using “to” means a range including numerical values described before and after “to” as a lower limit value and an upper limit value.
“Acrylic resin” means a resin obtained by polymerizing methacrylic acid or a derivative of acrylic acid, and a resin containing the derivative. Further, when not particularly limited, “(meth) acrylate” represents acrylate and methacrylate, and “(meth) acryl” represents acryl and methacryl.
Furthermore, the “slow axis direction” of the film is the direction in which the refractive index is maximum in the film plane, and the “fast axis direction” means the direction perpendicular to the slow axis in the film plane. .

[Optical Film and Optical Film Manufacturing Method]
The optical film of the present invention is an optical film having a base film containing a (meth) acrylic polymer as a main component and a low moisture-permeable layer laminated on the base film, The moisture permeability is 100 g / m ² / day or less and satisfies the formula (1).
Formula (1) 0.01 <= A / B <= 0.8
(In Formula (1), A represents the moisture permeability of the optical film which laminated | stacked the said low moisture-permeable layer on the base film which has a (meth) acrylic-type polymer as a main component, B represents the said (meth) acrylic-type heavy weight. (It represents the moisture permeability of the base film mainly composed of coalescence, which is a value after 24 hours at 40 ° C. and 90% relative humidity by the method of JIS 0208.)
With the above configuration, durability is excellent and moisture permeation and desorption can be reduced.

The optical film of the present invention more preferably satisfies the following formula (2), more preferably satisfies the following formula (3), and particularly preferably satisfies the following formula (4).
Formula (2) 0.01 <= A / B <= 0.7
Formula (3) 0.02 ≦ A / B ≦ 0.6
Formula (4) 0.04 ≦ A / B ≦ 0.5
The definitions of A and B in the formulas (2) to (4) are the same as the definitions of A and B in the formula (1).

Moreover, the method for producing an optical film of the present invention includes a step of forming a base film by melting and forming a thermoplastic resin, and a step of laminating a low moisture-permeable layer on the base film by coating. It is a manufacturing method of the optical film which has the low moisture-permeable layer laminated | stacked on the base film.
The moisture permeability of the optical film produced by the production method is 100 g / m ² / day or less, and preferably satisfies the following formula (1).
Formula (1) 0.01 <= A / B <= 0.8
(In Formula (1), A represents the moisture permeability of the optical film which laminated | stacked the said low moisture-permeable layer on the base film containing the said thermoplastic resin, and B represents the moisture permeability of the said base film. However, permeation | transmission. (The humidity is a value after 24 hours at 40 ° C. and 90% relative humidity by the method of JIS 0208.)
With the above configuration, the optical film of the present invention can be produced.

  Hereinafter, preferred embodiments of the optical film of the present invention and the production method thereof will be described.

{Characteristics of optical film}
(Optical film thickness)
5-100 micrometers is preferable, as for the film thickness (total film thickness after laminating | stacking a low moisture-permeable layer on a base film) of the optical film of this invention, 10-80 micrometers is more preferable, and 15-75 micrometers is especially preferable.

(Water vapor transmission rate of optical film)
The moisture permeability of the optical film of the present invention is measured under the conditions of 40 ° C. and 90% relative humidity based on JIS Z-0208.
The moisture permeability of the optical film of the present invention is 100 g / m ² / day or less, preferably 90 g / m ² / day or less, more preferably 80 g / m ² / day or less, and 70 g / m. ² / day or less is more preferable, and 60 g / m ² / day is particularly preferable. If the moisture permeability is 100 g / m ² / day or less, the room temperature of the liquid crystal display device,
It is possible to suppress warpage of the liquid crystal cell and display unevenness during black display after aging in a high humidity and high temperature and high humidity environment.

(Retardation)
In the optical film of the present invention, Re and Rth (defined by the following formulas (I) and (II)) measured at a wavelength of 590 nm preferably satisfy the formulas (III) and (IV).
Formula (I) Re = (nx−ny) × d
Formula (II) Rth = {(nx + ny) / 2−nz} × d
Formula (III) | Re | ≦ 50 nm
Formula (IV) | Rth | ≦ 300 nm
(In the formulas (I) to (IV), nx is the refractive index in the slow axis direction in the film plane of the optical film, and ny is the refractive index in the fast axis direction in the film plane of the optical film. , Nz is the refractive index in the film thickness direction of the optical film, and d is the film thickness (nm) of the optical film.)
In the optical film of the present invention, the above formulas (III) and (IV) may be satisfied at at least one point in the film plane, but the above formulas (III) and (IV) are arbitrary at any point in the film plane. ) Is preferably satisfied.
Re and Rth of the optical film of the present invention are adjusted by adjusting the Re and Rth of the base film described later, the composition and film thickness of the low moisture permeable layer, the total film thickness of the optical film of the present invention, and the like. Can do.

{Low moisture permeability layer}
(Thickness of low moisture permeable layer)
In the present invention, the low moisture permeability layer refers to a layer having a low moisture permeability per unit film thickness. More specifically, the moisture permeability per 10 μm thickness is 5.0 to 250 g / m ² / day. Preferably there is.
The thickness of the low moisture permeable layer is preferably 1 to 20 μm, more preferably 2 to 18 μm, and particularly preferably 3 to 17 μm.

(Moisture permeability per unit film thickness of low moisture permeable layer)
It is generally known that the moisture permeability in a steady state is inversely proportional to the film thickness. Accordingly, the moisture permeability that can be reached by the low moisture permeable layer in the range of the film thickness is determined by the moisture permeability per unit film thickness that is a characteristic value of the material, and the smaller the value, the lower the moisture permeability. On the other hand, the moisture permeability can be adjusted by adjusting the film thickness of the low moisture permeable layer based on the above relationship. However, if the moisture permeability per unit film thickness is too low, it becomes difficult to control the moisture permeability of the optical film.
In view of both moisture permeability per thickness 10μm of the low moisture-permeable layer is preferably 5.0~250g ^/ m 2 ^/ day, more preferably ^{10~200g / m 2 / day, 20~150g} / m 2 / Day is more preferable, and 30 to 130 g / m ² / day is particularly preferable. (The moisture permeability is the value after 24 hours at 40 ° C. and 90% relative humidity by the method of JIS 0208.)
The moisture permeability per 10 μm of the low moisture permeable layer can be estimated as follows from the moisture permeability of the base film and the optical film and the film thickness of the low moisture permeable layer.

From the gas permeation type of composite films (for example, “Science of Barrier Properties of Packaging Materials (Basic Course of Packaging Science 5)” p.68-72 Tsutomu Nakagawa, Japan Society for Packaging Science), J _f , When the moisture permeability of the material film is J _s and the moisture permeability of the low moisture permeable layer when the optical film is separated into the base film and the low moisture permeable layer is J _b , the following equation is established.
1 / J _f = 1 / J _s + 1 / J _b Expression (n)
The moisture permeability J _f of the optical film and the moisture permeability J _s of the base film can be directly measured, and the moisture permeability J _b of the low moisture permeable layer can be obtained by calculation based on those measured values.

The moisture permeability C _b (10 μm) with respect to the film thickness of 10 μm of the low moisture permeable layer can be expressed by the following formula based on J _b calculated above.
C _b (10 μm) = J _b × d _b / 10 [g / m ² / day]
(Here, d _b [μm] is the film thickness of the low moisture-permeable layer, and can be determined from the film thickness difference before and after the lamination of the low moisture-permeable layer as described above.)

(Composition of low moisture permeable layer)
The low moisture permeable layer that can be used in the optical film of the present invention may be formed of any material as long as the optical film of the present invention satisfies the above formula (1). A layer formed from a composition containing at least a compound having a cyclic aliphatic hydrocarbon group and an unsaturated double bond, or a layer having a resin containing at least a repeating unit derived from a chlorine-containing vinyl monomer And is formed from a composition containing a compound having a cyclic aliphatic hydrocarbon group and an unsaturated double bond in the molecule and / or a compound having a fluorene ring and an unsaturated double bond group in the molecule. More preferably, it is a layer.

  About the layer formed from the composition containing a compound having a cyclic aliphatic hydrocarbon group and an unsaturated double bond group in the molecule and / or a compound having a fluorene ring and an unsaturated double bond group in the molecule explain.

<< Layer formed from a composition mainly composed of a compound having a cycloaliphatic hydrocarbon group and an unsaturated double bond group in the molecule >>
In the present invention, it is formed from a compound containing a compound having a cyclic aliphatic hydrocarbon group and an unsaturated double bond group in the molecule and / or a compound having a fluorene skeleton and an unsaturated double bond group in the molecule. The layer comprises a compound having a cyclic aliphatic hydrocarbon group and an unsaturated double bond group in the molecule in order to impart low moisture permeability, and if necessary, a polymerization initiator, A composition containing translucent particles, a fluorine-containing or silicone compound, and a solvent can be formed by coating, drying, and curing directly on a support or through another layer. Each component will be described below.

[Compound having a cyclic aliphatic hydrocarbon group and an unsaturated double bond group in the molecule]
By using a compound having a cyclic aliphatic hydrocarbon group and an unsaturated double bond group in the molecule, low moisture permeability and high film strength can be realized. Although the details are not clear, by using a compound having a cycloaliphatic hydrocarbon group in the molecule, a hydrophobic cycloaliphatic hydrocarbon group is introduced into the low moisture-permeable layer, and is hydrophobized. Prevents uptake of molecules and reduces moisture permeability. Moreover, by having an unsaturated double bond group in a molecule | numerator, a crosslinking point density is raised and the diffusion path | route of the water molecule in a low moisture-permeable layer is restrict | limited. Increasing the crosslink point density also has the effect of relatively increasing the density of the cyclic aliphatic hydrocarbon group, making the inside of the low moisture permeable layer more hydrophobic, preventing the adsorption of water molecules, and reducing the moisture permeability. it is conceivable that.
In order to increase the crosslinking point density, the number of unsaturated double bond groups in the molecule is more preferably 2 or more.

The cyclic aliphatic hydrocarbon group is preferably a group derived from an alicyclic compound having 7 or more carbon atoms, more preferably a group derived from an alicyclic compound having 10 or more carbon atoms, and further preferably Is a group derived from an alicyclic compound having 12 or more carbon atoms.
The cycloaliphatic hydrocarbon group is particularly preferably a group derived from a polycyclic compound such as bicyclic or tricyclic.
More preferably, the central skeleton of the compound described in the claims of JP-A No. 2006-215096, the central skeleton of the compound described in JP-A No. 2001-10999, or the skeleton of an adamantane derivative may be used.

  As the cyclic aliphatic hydrocarbon group (including a linking group), a group represented by any one of the following general formulas (I) to (V) is preferable, and the following general formula (I), (II), or (IV) Is more preferable, and a group represented by the following general formula (I) is more preferable.

  In general formula (I), L and L ′ each independently represent a divalent or higher linking group. n represents an integer of 1 to 3.

  In general formula (II), L and L ′ each independently represent a divalent or higher linking group. n represents an integer of 1 to 2.

  In general formula (III), L and L ′ each independently represent a divalent or higher linking group. n represents an integer of 1 to 2.

  In general formula (IV), L and L ′ each independently represent a divalent or higher valent linking group, and L ″ represents a hydrogen atom or a divalent or higher valent linking group.

  In general formula (V), L and L ′ each independently represent a divalent or higher linking group.

  Specific examples of the cyclic aliphatic hydrocarbon group include norbornyl, tricyclodecanyl, tetracyclododecanyl, pentacyclopentadecanyl, adamantyl, diamantanyl and the like.

Examples of the unsaturated double bond group include 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 and —C (O) OCH═CH ₂ Is preferred. Particularly preferably, a compound containing three or more (meth) acryloyl groups in one molecule described below can be used.

A compound having a cycloaliphatic hydrocarbon group and having 3 or more unsaturated double bond groups in the molecule has the above-described cycloaliphatic hydrocarbon group and the group having an unsaturated double bond as a linking group. It is comprised by connecting via.
As the linking group, a single bond, an alkylene group having 1 to 6 carbon atoms which may be substituted, an amide group which may be substituted at the N position, a carbamoyl group which may be substituted at the N position, an ester group, Examples include oxycarbonyl groups, ether groups, and the like, and groups obtained by combining these.

These compounds include, for example, polyols such as diols and triols having the above cyclic aliphatic hydrocarbon groups, and carboxylic acids and carboxylic acid derivatives of compounds having (meth) acryloyl groups, vinyl groups, styryl groups, allyl groups, etc. It can be easily synthesized by a one-step or two-step reaction with an epoxy derivative, an isocyanate derivative or the like.
Preferably, compounds such as (meth) acrylic acid, (meth) acryloyl chloride, (meth) acrylic anhydride, glycidyl (meth) acrylate, and compounds described in WO2012 / 00316A (eg, 1,1-bis ( (Acryloxymethyl) ethyl isocyanate) can be synthesized by reacting with a polyol having the above cyclic aliphatic hydrocarbon group.

  Hereinafter, although the preferable specific example of the compound which has a cyclic aliphatic hydrocarbon group and has an unsaturated double bond group is shown, this invention is not limited to these.

[Compound having a fluorene skeleton and an unsaturated double bond in the molecule]
A compound having a fluorene skeleton and an unsaturated double bond in the molecule is a binder in a layer formed of a composition mainly comprising a compound having a cyclic aliphatic hydrocarbon group and an unsaturated double bond group in the molecule. Function as. In addition, a compound having a fluorene skeleton and an unsaturated double bond group can function as a curing agent, and can improve the strength and scratch resistance of the coating film and at the same time impart low moisture permeability. it can. By further including such a compound, the low moisture permeability can be further improved.
In order to increase the crosslinking point density, the number of unsaturated double bond groups in the molecule is more preferably 2 or more.

  The compound having a fluorene skeleton and an unsaturated double bond in the molecule is preferably represented by the following general formula (VI).

(In formula (VI), R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ each independently represents a monovalent substituent, and m, n, p and q are each independently 0 Represents an integer of ˜4, and at least one of R ¹ and R ² represents a monovalent organic group having an ethylenically unsaturated group.)

  The compound having a fluorene skeleton and an unsaturated double bond in the molecule is preferably represented by the following general formula (VII).

(Wherein R ₇ and R ₈ represent a hydrogen atom or a methyl group, r and s represent an integer of 0 to 5)

[Compound having an unsaturated double bond group not having a cyclic aliphatic hydrocarbon group]
In the composition for forming a low moisture permeable layer used in the present invention, a compound having an unsaturated double bond having no cyclic aliphatic hydrocarbon group in the molecule can be used in combination as long as the effects of the present invention are not impaired.

  The compound having an unsaturated double bond group not having a cycloaliphatic hydrocarbon group is preferably a (meth) acrylate compound not having a cycloaliphatic hydrocarbon group, and is a (meth) acrylic alkylene glycol. Acid diesters, (meth) acrylic acid diesters of polyoxyalkylene glycol, (meth) acrylic acid diesters of polyhydric alcohols, (meth) acrylic acid diesters of ethylene oxide or propylene oxide adducts, epoxy (meth) acrylates , Urethane (meth) acrylates, polyester (meth) acrylates, and the like.

  Among these, esters of polyhydric alcohol and (meth) acrylic acid are preferable. For example, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol (meth) acrylate, ethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate , Pentaerythritol tetra (meth) acrylate, pentaerythritol tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, EO modified trimethylolpropane tri (meth) acrylate, PO modified trimethylolpropane tri (meth) acrylate, EO modified Tri (meth) acrylate phosphate, trimethylolethane tri (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, dipentaerythritol tetra (meth) acrylate Rate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, polyurethane polyacrylate, polyester polyacrylate and caprolactone-modified tris (acryloyloxyethyl) isocyanurate.

  Commercially available polyfunctional acrylate compounds having a (meth) acryloyl group can be used, such as NK ester A-TMMT manufactured by Shin-Nakamura Chemical Co., Ltd., KAYARAD DPHA manufactured by Nippon Kayaku Co., Ltd. Can be mentioned. The polyfunctional monomer is described in paragraphs [0114] to [0122] of JP-A-2009-98658, and the same applies to the present invention.

  The compound having an unsaturated double bond group that does not have a cycloaliphatic hydrocarbon group is a compound having a hydrogen bonding substituent, adhesion to the support, low curl, and fluorine-containing compounds described later. Or it is preferable from the point of the fixability of a silicone type compound. The hydrogen-bonding substituent refers to a substituent in which an atom having a large electronegativity such as nitrogen, oxygen, sulfur, or halogen and a hydrogen bond are covalently bonded. Specifically, OH—, SH—, — NH-, CHO-, CHN- and the like can be mentioned, and urethane (meth) acrylates and (meth) acrylates having a hydroxyl group are preferable. Commercially available polyfunctional acrylates having a (meth) acryloyl group can also be used. Shin Nakamura Chemical Co., Ltd. NK Oligo U4HA, NK Ester A-TMM-3, Nippon Kayaku Co., Ltd. KAYARAD PET-30 etc. can be mentioned.

[Inorganic layered compound]
In order to further reduce the moisture permeability of the coating layer of the present invention, it is also preferable to disperse the inorganic layered compound in a binder that can be used for the above-described low moisture permeability layer. Since the inorganic layered compound has a hydrophilic surface, it is preferably subjected to an organic treatment.

The inorganic layered compound 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.). In addition, a synthetic inorganic layered compound is also preferably used. Examples of the synthetic inorganic layered compound include synthetic smectite (hectorite, saponite, stevensite, etc.), synthetic mica, etc., preferably smectite, montmorillonite, mica, montmorillonite, mica. Is more preferable. As an inorganic layered compound that can be used as a commercial product, MEB-3 (synthetic mica aqueous dispersion manufactured by Coop Chemical Co., Ltd.), ME-100 (synthetic mica manufactured by Coop Chemical Co., Ltd.), S1ME (manufactured by Coop Chemical Co., Ltd.) Synthetic mica), SWN (Synthetic smectite manufactured by Corp Chemical Co., Ltd.), SWF (Synthetic smectite manufactured by Corp Chemical Co., Ltd.), Kunipia F (Purified bentonite manufactured by Kunimine Chemical Co., Ltd.), Bengel (Purified by Hojun Co., Ltd.) Bentonite), Wengel HV (Purified bentonite manufactured by Hojung Co., Ltd.), Wenger FW (Purified bentonite manufactured by Hojun Co., Ltd.), Wenger Bright 11 (Purified bentonite manufactured by Hojun Co., Ltd.), Wengel Bright 23 (Purified by Hojun Co., Ltd.) Bentonite), Wenger Bright 25 (Hojung Co., Ltd.) Purification bentonite), Wenger A (HOJUN Co. purification bentonite), can be used Wenger 2M (HOJUN Co. purified bentonite) or the like.
Such inorganic layered compounds are preferably those obtained by subjecting these inorganic layered compounds to organic treatment.

  The swellable layered inorganic compound is preferably finely divided from the viewpoint of achieving both low moisture permeability and adhesion between the substrate and the low moisture permeability 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 0.1 to 8 μm, and particularly preferably 0.1 to 6 μm. .

(Polymerization initiator)
The composition containing a compound having a cyclic aliphatic hydrocarbon group and an unsaturated double bond group in the molecule and / or a compound having a fluorene skeleton and an unsaturated double bond group in the molecule contains a polymerization initiator. It is preferable. As the polymerization initiator, a photopolymerization initiator is preferable.
As photopolymerization initiators, acetophenones, benzoins, benzophenones, phosphine oxides, ketals, anthraquinones, thioxanthones, azo compounds, peroxides, 2,3-dialkyldione compounds, disulfide compounds, Examples include fluoroamine compounds, aromatic sulfoniums, lophine dimers, onium salts, borate salts, active esters, active halogens, inorganic complexes, and coumarins. Specific examples, preferred embodiments, commercially available products, and the like of the photopolymerization initiator are described in paragraphs [0133] to [0151] of JP-A-2009-098658, and can be suitably used in the present invention as well. it can.

  “Latest UV Curing Technology” {Technical Information Association, Inc.} (1991), p. 159, and “UV Curing System” written by Kiyomi Kato (published by the General Technology Center in 1989), p. Various examples are also described in 65-148 and are useful in the present invention.

  Commercially available photocleavable photoradical polymerization initiators include “Irgacure 651”, “Irgacure 184”, “Irgacure 819”, “Irgacure 907”, “Irgacure 1870” (CGI) manufactured by Ciba Specialty Chemicals Co., Ltd. -403 / Irgacure 184 = 7/3 mixing initiator), "Irgacure 500", "Irgacure 369", "Irgacure 1173", "Irgacure 2959", "Irgacure 4265", "Irgacure 4263", "Irgacure 127", " OXE01 ”, etc .;“ Kayacure DETX-S ”,“ Kayacure BP-100 ”,“ Kayacure BDK ”,“ Kayacure CTX ”,“ Kayacure BMS ”,“ Kayacure 2-EAQ ”,“ Cayacure ”manufactured by Nippon Kayaku Co., Ltd. "ABQ", " “Yacure CPTX”, “Kayacure EPD”, “Kayacure ITX”, “Kayacure QTX”, “Kayacure BTC”, “Kayacure MCA”, etc .; , KIP150, TZT) ", etc., and combinations thereof are preferred examples.

  Light in a composition containing a compound having a cyclic aliphatic hydrocarbon group and an unsaturated double bond group in the molecule and / or a compound having a fluorene skeleton and an unsaturated double bond group in the molecule used in the present invention The content of the polymerization initiator is set to 0. 0 with respect to the total solid content in the composition because the polymerizable compound contained in the composition is polymerized and the starting point is set not to increase too much. 5-8 mass% is preferable and 1-5 mass% is more preferable.

[Ultraviolet absorber]
The optical film of the present invention including a low moisture permeable layer is used for a polarizing plate or a liquid crystal display device member, but contains a UV absorber in the low moisture permeable layer from the viewpoint of preventing deterioration of the polarizing plate or liquid crystal. Thus, ultraviolet absorption can be imparted to the optical film.

〔solvent〕
The composition containing as a main component a compound having a cyclic aliphatic hydrocarbon group and an unsaturated double bond group in the molecule used in the present invention can contain a solvent. As the solvent, various solvents can be used in consideration of the solubility of the monomer, the drying property during coating, the dispersibility of the translucent particles, and the like. Examples of such organic solvents include dibutyl ether, dimethoxyethane, diethoxyethane, propylene oxide, 1,4-dioxane, 1,3-dioxolane, 1,3,5-trioxane, tetrahydrofuran, anisole, phenetole, dimethyl carbonate, carbonic acid. Methyl ethyl, diethyl carbonate, acetone, methyl ethyl ketone (MEK), diethyl ketone, dipropyl ketone, diisobutyl ketone, cyclopentanone, cyclohexanone, methylcyclohexanone, ethyl formate, propyl formate, pentyl formate, methyl acetate, ethyl acetate, propyl acetate, Methyl propionate, ethyl propionate, γ-ptyrolactone, methyl 2-methoxyacetate, methyl 2-ethoxyacetate, ethyl 2-ethoxyacetate, ethyl 2-ethoxypropionate, 2-metho Siethanol, 2-propoxyethanol, 2-butoxyethanol, 1,2-diacetoxyacetone, acetylacetone, diacetone alcohol, methyl acetoacetate, methyl acetoacetate and other methyl alcohol, ethyl alcohol, isopropyl alcohol, n-butyl alcohol, cyclohexyl Alcohol, isobutyl acetate, methyl isobutyl ketone (MIBK), 2-octanone, 2-pentanone, 2-hexanone, ethylene glycol ethyl ether, ethylene glycol isopropyl ether, ethylene glycol butyl ether, propylene glycol methyl ether, ethyl carbitol, butyl carbitol , Hexane, heptane, octane, cyclohexane, methylcyclohexane, ethylcyclohexane, benzene, tolu Examples thereof include ene and xylene, and these can be used alone or in combination of two or more.

  It is preferable to use at least one of dimethyl carbonate, methyl acetate, ethyl acetate, methyl ethyl ketone, acetylacetone, and acetone, more preferably dimethyl carbonate or methyl acetate, and particularly preferably methyl acetate.

  A solvent is used so that the solid content concentration of the composition mainly composed of a compound having a cycloaliphatic hydrocarbon group and an unsaturated double bond group in the molecule is 20-80% by mass. It is preferably used, more preferably 30 to 75% by mass, and still more preferably 40 to 70% by mass.

(Configuration of low moisture permeable layer, manufacturing method)
The low moisture-permeable layer may be a single layer or a plurality of layers. When laminating a plurality of low moisture permeable layers, all of them may be provided on one side of the base material, or may be provided separately on both sides. The lamination method of the low moisture permeable layer is not particularly limited, but the low moisture permeable layer is formed as a co-cast with the base film, or the low moisture permeable layer is applied on the base film. It is preferable to provide, and it is more preferable to provide the low moisture-permeable layer on the base film by coating.

  The low moisture permeable layer of the optical film of the present invention preferably has a hard coat layer function, an antireflection function, an antifouling function and the like in addition to the low moisture permeability.

{Base film}
The base film contains a (meth) acrylic polymer as a main component. In the present application, that the base film is mainly composed of a (meth) acrylic polymer means that the base film contains 50% by mass or more of the (meth) acrylic polymer.

  The (meth) acrylic polymer is a concept including both a methacrylic polymer and an acrylic polymer. The (meth) acrylic polymer also includes acrylate / methacrylate derivatives, in particular, acrylate ester / methacrylate ester (co) polymers.

((Meth) acrylic polymer)
The repeating structural unit of the (meth) acrylic polymer is not particularly limited. The (meth) acrylic polymer preferably has a repeating structural unit derived from a (meth) acrylic acid ester monomer as a repeating structural unit.

  The (meth) acrylic polymer further polymerizes at least one selected from a hydroxyl group-containing monomer, an unsaturated carboxylic acid, and a monomer represented by the following general formula (201) as a repeating structural unit. It may contain a repeating structural unit constructed by

Formula (201)
CH ₂ = C (X) R ²⁰¹

(In the formula, R ²⁰¹ represents a hydrogen atom or a methyl group, and X represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an aryl group, a —CN group, a —CO—R ²⁰² group, or —O—CO—R. ²⁰³ represents a group, and R ²⁰² and R ²⁰³ represent a hydrogen atom or an organic residue having 1 to 20 carbon atoms.)

The (meth) acrylic acid ester is not particularly limited, and examples thereof include methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, t-butyl acrylate, cyclohexyl acrylate, and benzyl acrylate. Acrylic acid esters; methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, cyclohexyl methacrylate, methacrylic acid esters such as benzyl methacrylate; These may be used alone or in combination of two or more. Among these, methyl methacrylate is particularly preferable from the viewpoint of excellent heat resistance and transparency.
When the (meth) acrylic acid ester is used, the content ratio in the monomer component to be subjected to the polymerization step is preferably 10 to 100% by mass, more preferably 10 in order to sufficiently exhibit the effects of the present invention. -100 mass%, More preferably, it is 40-100 mass%, Most preferably, it is 50-100 mass%.

The hydroxyl group-containing monomer is not particularly limited. For example, 2- (hydroxyalkyl) acrylic acid ester such as α-hydroxymethylstyrene, α-hydroxyethylstyrene, methyl 2- (hydroxyethyl) acrylate; 2 2- (hydroxyalkyl) acrylic acid such as-(hydroxyethyl) acrylic acid; and the like. These may be used alone or in combination of two or more.
In the case of using the hydroxyl group-containing monomer, the content ratio in the monomer component to be subjected to the polymerization step is preferably 0 to 30% by mass, more preferably 0 to 0% in order to sufficiently exhibit the effects of the present invention. 20 mass%, More preferably, it is 0-15 mass%, Most preferably, it is 0-10 mass%.

Examples of the unsaturated carboxylic acid include acrylic acid, methacrylic acid, crotonic acid, α-substituted acrylic acid, α-substituted methacrylic acid and the like. These may be used alone or in combination of two or more. You may use together. Among these, acrylic acid and methacrylic acid are preferable in that the effects of the present invention are sufficiently exhibited.
When the unsaturated carboxylic acid is used, the content ratio in the monomer component to be subjected to the polymerization step is preferably 0 to 30% by mass, more preferably 0 to 20%, in order to sufficiently exhibit the effects of the present invention. It is 0 mass%, More preferably, it is 0-15 mass%, Most preferably, it is 0-10 mass%.

Examples of the monomer represented by the general formula (201) include styrene, vinyl toluene, α-methyl styrene, acrylonitrile, methyl vinyl ketone, ethylene, propylene, vinyl acetate, and the like. You may use, and may use 2 or more types together. Among these, styrene and α-methylstyrene are particularly preferable in that the effects of the present invention are sufficiently exhibited.
When using the monomer represented by the general formula (201), the content ratio in the monomer component to be subjected to the polymerization step is preferably 0 to 30 mass in order to sufficiently exhibit the effects of the present invention. %, More preferably 0 to 20% by mass, still more preferably 0 to 15% by mass, and particularly preferably 0 to 10% by mass.

[(Meth) acrylic polymer having a ring structure in the main chain]
Among (meth) acrylic polymers, those having a ring structure in the main chain are preferred. By introducing a ring structure into the main chain, the rigidity of the main chain can be improved and the heat resistance can be improved.
In the present invention, among (meth) acrylic polymers having a ring structure in the main chain, a polymer having a lactone ring structure in the main chain, a polymer having a glutaric anhydride ring structure in the main chain, and a glutarimide ring in the main chain It is preferably any of polymers having a structure. Among these, a polymer containing a lactone ring structure in the main chain is more preferable.
The following polymers having a ring structure in these main chains will be described in order.

((Meth) acrylic polymer with lactone ring structure in the main chain)
The (meth) acrylic polymer having a lactone ring structure in the main chain (hereinafter also referred to as a lactone ring-containing polymer) is not particularly limited as long as it is a (meth) acrylic polymer having a lactone ring in the main chain, but preferably Has a lactone ring structure represented by the following general formula (401).

  General formula (401):

In the general formula (401), R ⁴⁰¹ , R ⁴⁰² and R ⁴⁰³ each independently represent a hydrogen atom or an organic residue having 1 to 20 carbon atoms, and the organic residue may contain an oxygen atom. . Here, the organic residue having 1 to 20 carbon atoms is preferably a methyl group, an ethyl group, an isopropyl group, an n-butyl group, a t-butyl group, or the like.

  The content ratio of the lactone ring structure represented by the general formula (401) in the structure of the lactone ring-containing polymer is preferably 5 to 90% by mass, more preferably 10 to 70% by mass, and still more preferably 10 to 60% by mass. %, Particularly preferably 10 to 50% by mass. By setting the content ratio of the lactone ring structure to 5% by mass or more, the heat resistance and surface hardness of the obtained polymer tend to be improved, and by setting the content ratio of the lactone ring structure to 90% by mass or less. The moldability of the obtained polymer tends to be improved.

  The method for producing the lactone ring-containing polymer is not particularly limited, but preferably, after obtaining a polymer (p) having a hydroxyl group and an ester group in the molecular chain by a polymerization step, the obtained polymer ( It is obtained by carrying out a lactone cyclization condensation step for introducing a lactone ring structure into the polymer by heat-treating p).

  The mass average molecular weight of the lactone ring-containing polymer is preferably 1,000 to 2,000,000, more preferably 5,000 to 1,000,000, still more preferably 10,000 to 500,000, particularly preferably. 50,000 to 500,000.

  The lactone ring-containing polymer has a mass reduction rate within a range of 150 to 300 ° C. in dynamic TG measurement, preferably 1% or less, more preferably 0.5% or less, and still more preferably 0.3% or less. It is good. As a method for measuring dynamic TG, the method described in JP-A-2002-138106 can be used.

  Since the lactone ring-containing polymer has a high cyclization condensation reaction rate, there is little dealcoholization reaction in the production process of the molded product, and bubbles and silver stripes (silver streaks) are formed in the molded product after molding due to the alcohol. The disadvantage of entering can be avoided. Furthermore, since the lactone ring structure is sufficiently introduced into the polymer due to a high cyclization condensation reaction rate, the obtained lactone ring-containing polymer has high heat resistance.

  The lactone ring-containing polymer has a coloring degree (YI) of preferably 6 or less, more preferably 3 or less, still more preferably 2 or less, and particularly preferably 1 or less when a chloroform solution having a concentration of 15% by mass is used. . If the degree of coloring (YI) is 6 or less, problems such as loss of transparency due to coloring are unlikely to occur, and therefore, it can be preferably used in the present invention.

  The lactone ring-containing polymer has a 5% mass reduction temperature in thermal mass spectrometry (TG) of preferably 330 ° C. or higher, more preferably 350 ° C. or higher, and still more preferably 360 ° C. or higher. The 5% mass reduction temperature in thermal mass spectrometry (TG) is an indicator of thermal stability, and by setting it to 330 ° C. or higher, sufficient thermal stability tends to be exhibited. The thermal mass spectrometry can use the apparatus for measuring the dynamic TG.

  The lactone ring-containing polymer has a glass transition temperature (Tg) of preferably 115 ° C. or higher, more preferably 125 ° C. or higher, further preferably 130 ° C. or higher, particularly preferably 135 ° C. or higher, and most preferably 140 ° C. or higher. .

  The total amount of residual volatile components contained in the lactone ring-containing polymer is preferably 5,000 ppm or less, more preferably 2,000 ppm or less, still more preferably 1,500 ppm, and particularly preferably 1,000 ppm. If the total amount of residual volatile components is 5,000 ppm or less, it is preferable because coloring defects due to alteration during molding, foaming, and molding defects such as silver streak are unlikely to occur.

  The lactone ring-containing polymer has a total light transmittance of 85% or more, more preferably 88% or more, and still more preferably measured by a method based on ASTM-D-1003 for a molded product obtained by injection molding. 90% or more. The total light transmittance is an index of transparency, and when it is 85% or more, the transparency tends to be improved.

In the case of a polymerization form using a solvent, the polymerization solvent is not particularly limited. For example, aromatic hydrocarbon solvents such as toluene, xylene, and ethylbenzene; ketone solvents such as methyl ethyl ketone and methyl isobutyl ketone; ether solvents such as tetrahydrofuran Etc., and only one of these may be used, or two or more may be used in combination.
In the first aspect of the production method of the present invention, the (meth) acrylic resin is dissolved in an organic solvent and cast by solution casting. Therefore, the organic solvent at the time of synthesizing the (meth) acrylic resin is There is no limitation as compared with the case of performing melt film formation, and synthesis may be performed using an organic solvent having a high boiling point.

During the polymerization reaction, a polymerization initiator may be added as necessary. Although it does not specifically limit as a polymerization initiator, For example, cumene hydroperoxide, diisopropylbenzene hydroperoxide, di-t-butyl peroxide, lauroyl peroxide, benzoyl peroxide, t-butylperoxyisopropyl carbonate, t-amyl Organic peroxides such as peroxy-2-ethylhexanoate; 2,2′-azobis (isobutyronitrile), 1,1′-azobis (cyclohexanecarbonitrile), 2,2′-azobis (2, Azo compounds such as 4-dimethylvaleronitrile), and the like. These may be used alone or in combination of two or more. The amount of the polymerization initiator used is not particularly limited as long as it is appropriately set according to the combination of the monomers used and the reaction conditions.
The weight average molecular weight of the polymer can be adjusted by adjusting the amount of the polymerization initiator.

  When performing the polymerization, it is preferable to control the concentration of the produced polymer in the polymerization reaction mixture to be 50% by mass or less in order to suppress gelation of the reaction solution. Specifically, when the concentration of the produced polymer in the polymerization reaction mixture exceeds 50% by mass, it is preferable that the polymerization solvent is appropriately added to the polymerization reaction mixture and controlled to be 50% by mass or less. . The concentration of the produced polymer in the polymerization reaction mixture is more preferably 45% by mass or less, still more preferably 40% by mass or less.

  The form in which the polymerization solvent is appropriately added to the polymerization reaction mixture is not particularly limited, and the polymerization solvent may be added continuously or intermittently. By controlling the concentration of the produced polymer in the polymerization reaction mixture in this way, the gelation of the reaction solution can be more sufficiently suppressed. The polymerization solvent to be added may be the same type of solvent used during the initial charging of the polymerization reaction or may be a different type of solvent, but is the same as the solvent used during the initial charging of the polymerization reaction. It is preferable to use different types of solvents. Further, the polymerization solvent to be added may be only one type of solvent or a mixed solvent of two or more types.

(Polymer having glutaric anhydride ring structure in the main chain)
The polymer having a glutaric anhydride ring structure in the main chain is a polymer having glutaric anhydride units.

  The polymer having a glutaric anhydride unit preferably has a glutaric anhydride unit represented by the following general formula (101) (hereinafter referred to as a glutaric anhydride unit).

  Formula (101):

In general formula (101), R ³¹ and R ³² each independently represent a hydrogen atom or an organic residue having 1 to 20 carbon atoms. The organic residue may contain an oxygen atom. R ³¹ and R ³² particularly preferably represent the same or different hydrogen atoms or alkyl groups having 1 to 5 carbon atoms.

  The polymer having a glutaric anhydride unit is preferably a (meth) acrylic polymer containing a glutaric anhydride unit. The (meth) acrylic polymer preferably has a glass transition temperature (Tg) of 120 ° C. or higher from the viewpoint of heat resistance.

  As content of the glutaric anhydride unit with respect to a (meth) acrylic-type polymer, 5-50 mass% is preferable, More preferably, it is 10-45 mass%. When the content is 5% by mass or more, more preferably 10% by mass or more, an effect of improving heat resistance can be obtained, and further an effect of improving weather resistance can be obtained.

Moreover, it is preferable that said (meth) acrylic-type copolymer contains the repeating unit based on unsaturated carboxylic-acid alkylester further. As the repeating unit based on the unsaturated carboxylic acid alkyl ester, for example, those represented by the following general formula (102) are preferable.
Formula _{(102): - [CH 2} -C (R 41) (COOR 42)] -

In the general formula (102), R ⁴¹ represents hydrogen or an alkyl group having 1 to 5 carbon atoms, and R ⁴² ) represents an aliphatic or alicyclic hydrocarbon group having 1 to 6 carbon atoms, or one or more carbon atoms. Represents an aliphatic or alicyclic hydrocarbon group having 1 to 6 carbon atoms substituted by the number of hydroxyl groups or halogen.

The monomer corresponding to the repeating unit represented by the general formula (102) is represented by the following general formula (103).
Formula _{(103): CH 2 = C} (R 41) (COOR 42)

  Preferred examples of such monomers include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, n-butyl (meth) acrylate, (meth) acrylic acid. t-butyl, n-hexyl (meth) acrylate, cyclohexyl (meth) acrylate, chloromethyl (meth) acrylate, 2-chloroethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, (meth ) 3-hydroxypropyl acrylate, 2,3,4,5,6-pentahydroxyhexyl (meth) acrylate and 2,3,4,5-tetrahydroxypentyl (meth) acrylate, among others, methacryl Methyl acid is most preferably used. These may be used individually by 1 type, or may use 2 or more types together.

  The content of the unsaturated carboxylic acid alkyl ester unit relative to the (meth) acrylic polymer is preferably 50 to 95% by mass, more preferably 55 to 90% by mass. A (meth) acrylic polymer having a glutaric anhydride unit and an unsaturated carboxylic acid alkyl ester unit is obtained by polymerizing a copolymer having an unsaturated carboxylic acid alkyl ester unit and an unsaturated carboxylic acid unit, for example. It can be obtained by cyclization.

As an unsaturated carboxylic acid unit, what is represented, for example by the following general formula (104) is preferable.
Formula _{(104): - [CH 2} -C (R 51) (COOH)] -
Here, R ⁵¹ represents hydrogen or an alkyl group having 1 to 5 carbon atoms.

Preferable specific examples of the monomer for deriving the unsaturated carboxylic acid unit include a compound represented by the following general formula (105) which is a monomer corresponding to the repeating unit represented by the general formula (104), and Examples thereof include maleic acid and a hydrolyzate of maleic anhydride, and acrylic acid and methacrylic acid are preferable, and methacrylic acid is more preferable in terms of excellent thermal stability.
Formula _{(105): CH 2 = C} (R 51) (COOH)

  These may be used individually by 1 type, or may use 2 or more types together. As described above, an acrylic thermoplastic copolymer having a glutaric anhydride unit and an unsaturated carboxylic acid alkyl ester-based unit is, for example, a copolymer having an unsaturated carboxylic acid alkyl ester-based unit and an unsaturated carboxylic acid unit. Since the polymer can be obtained by cyclization of the polymer, it may have an unsaturated carboxylic acid unit in its constituent unit.

  As content of the unsaturated carboxylic acid unit with respect to said (meth) acrylic-type polymer, 10 mass% or less is preferable, More preferably, it is 5 mass% or less. By setting the content to 10% by mass or less, it is possible to prevent a decrease in colorless transparency and retention stability.

  Moreover, the said (meth) acrylic-type polymer may have the other vinyl-type monomer unit which does not contain an aromatic ring in the range which does not impair the effect of this invention. Specific examples of other vinyl monomer units that do not contain an aromatic ring include the corresponding monomers: vinyl cyanide monomers such as acrylonitrile, methacrylonitrile, ethacrylonitrile; allyl glycidyl ether Maleic anhydride, itaconic anhydride; N-methylmaleimide, N-ethylmaleimide, N-cyclohexylmaleimide, acrylamide, methacrylamide, N-methylacrylamide, butoxymethylacrylamide, N-propylmethacrylamide; aminoethyl acrylate, acrylic Propylaminoethyl acid, dimethylaminoethyl methacrylate, ethylaminopropyl methacrylate, cyclohexylaminoethyl methacrylate; N-vinyldiethylamine, N-acetylvinylamine, allylamine, methallylamino , N- methyl-allyl amine; 2-isopropenyl - oxazoline, 2-vinyl - oxazoline, 2-acryloyl - oxazoline, and the like. These may be used alone or in combination of two or more.

  As content of the other vinyl-type monomer unit which does not contain an aromatic ring with respect to said (meth) acrylic-type polymer, 35 mass% or less is preferable.

  For vinyl monomer units containing an aromatic ring (N-phenylmaleimide, phenylaminoethyl methacrylate, p-glycidylstyrene, p-aminostyrene, 2-styryl-oxazoline, etc.), they have scratch resistance and weather resistance. Since there exists a tendency to reduce, it is preferable to keep it as 1 mass% or less as content with respect to the said (meth) acrylic-type polymer.

((Meth) acrylic polymer with glutarimide ring structure in the main chain)
A (meth) acrylic polymer having a glutarimide ring structure in the main chain (hereinafter also referred to as a glutarimide resin) has a desirable balance of properties in terms of optical properties and heat resistance by having a glutarimide ring structure in the main chain. Can be expressed. The (meth) acrylic polymer having a glutarimide ring structure in the main chain is at least the following general formula (301):

General formula (301)

Wherein R ³⁰¹ , R ³⁰² and R ³⁰³ are independently hydrogen or an unsubstituted or substituted alkyl group having 1 to 12 carbon atoms, a cycloalkyl group or an aryl group. It is preferable to contain a glutarimide resin having 20% by mass or more.

As preferred glutarimide units constituting the glutarimide resin used in the present invention, R ³⁰¹ and R ³⁰² are hydrogen or a methyl group, and R ³⁰³ is a methyl group or a cyclohexyl group. The glutarimide unit may be a single type, or may include a plurality of types in which R ³⁰¹ , R ³⁰² , and R ³⁰³ are different.

  A preferred second structural unit constituting the glutarimide resin used in the present invention is a unit composed of an acrylate ester or a methacrylate ester. Preferable acrylic acid ester or methacrylic acid ester structural unit includes methyl acrylate, ethyl acrylate, methyl methacrylate, methyl methacrylate and the like. Another preferred imidizable unit includes N-alkyl methacrylamide such as N-methyl methacrylamide and N-ethyl methacrylamide. These second structural units may be of a single type or may include a plurality of types.

  The content of the glutarimide unit represented by the general formula (301) in the glutarimide resin is 20% by mass or more based on the total repeating unit of the glutarimide resin. The preferable content of the glutarimide unit is 20% by mass to 95% by mass, more preferably 50 to 90% by mass, and still more preferably 60 to 80% by mass. When a glutarimide unit is smaller than this range, the heat resistance of the film obtained may be insufficient or transparency may be impaired. On the other hand, if it exceeds this range, the heat resistance is unnecessarily increased and it becomes difficult to form a film, the mechanical strength of the resulting film becomes extremely brittle, and the transparency may be impaired.

  The glutarimide-based resin may be further copolymerized with a third structural unit as necessary. Preferred examples of the third structural unit include styrene monomers such as styrene, substituted styrene and α-methylstyrene, acrylic monomers such as butyl acrylate, and nitrile monomers such as acrylonitrile and methacrylonitrile. , A structural unit obtained by copolymerizing maleimide monomers such as maleimide, N-methylmaleimide, N-phenylmaleimide, and N-cyclohexylmaleimide can be used. These may be directly copolymerized with the glutarimide unit and the imidizable unit in the glutarimide resin, and graft copolymerized with the resin having the glutarimide unit and the imidizable unit. It may be polymerized. When the third component is added, the content in the glutarimide resin is preferably 5 mol% or more and 30 mol% or less based on the total repeating units in the glutarimide resin.

  The glutarimide resin is described in US Pat. No. 3,284,425, US Pat. No. 4,246,374, JP-A-2-153904, and the like, and is obtained by using methyl methacrylate as a main raw material as a resin having an imidizable unit. It can be obtained by using a resin and imidizing the resin having an imidizable unit with ammonia or a substituted amine. When obtaining a glutarimide resin, a unit composed of acrylic acid, methacrylic acid, or an anhydride thereof may be introduced into the glutarimide resin as a reaction by-product. The presence of such a structural unit, particularly an acid anhydride, is not preferable because it reduces the total light transmittance and haze of the obtained film of the present invention. The acrylic acid or methacrylic acid content is 0.5 milliequivalent or less per gram of resin, preferably 0.3 milliequivalent or less, more preferably 0.1 milliequivalent or less. In addition, as seen in JP-A No. 02-153904, it is also possible to obtain a glutarimide resin by imidization using a resin mainly composed of N-methylacrylamide and methacrylic acid methyl ester.

The glutarimide resin preferably has a weight average molecular weight of 1 × 10 ⁴ to 5 × 10 ⁵ .

<Ultraviolet absorber>
The ultraviolet absorber preferably used for the base film will be described. The optical film of the present invention including the base film is used for a polarizing plate, a liquid crystal display member, or the like. From the viewpoint of preventing deterioration of the polarizing plate or the liquid crystal, an ultraviolet absorber is preferably used. As the ultraviolet absorber, those excellent in the ability to absorb ultraviolet rays having a wavelength of 370 nm or less and having little absorption of visible light having a wavelength of 400 nm or more are preferably used from the viewpoint of good liquid crystal display properties. Only one type of ultraviolet absorber may be used, or two or more types may be used in combination. For example, the ultraviolet absorber as described in Unexamined-Japanese-Patent No. 2001-72782 and Special Table 2002-543265 is mentioned. Specific examples of the ultraviolet absorber include oxybenzophenone compounds, benzotriazole compounds, salicylic acid ester compounds, benzophenone compounds, cyanoacrylate compounds, nickel complex compounds, and the like.

  Among them, 2- (2′-hydroxy-5′-methylphenyl) benzotriazole, 2- (2′-hydroxy-3 ′, 5′-di-tert-butylphenyl) benzotriazole, 2- (2′- Hydroxy-3'-tert-butyl-5'-methylphenyl) benzotriazole, 2- (2'-hydroxy-3 ', 5'-di-tert-butylphenyl) -5-chlorobenzotriazole, 2- (2 '-Hydroxy-3'-(3 ", 4", 5 ", 6" -tetrahydrophthalimidomethyl) -5'-methylphenyl) benzotriazole, 2,2-methylenebis (4- (1,1,3,3 -Tetramethylbutyl) -6- (2H-benzotriazol-2-yl) phenol), 2- (2'-hydroxy-3'-tert-butyl-5'-methyl) Enyl) -5-chlorobenzotriazole, 2,4-dihydroxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxy-5-sulfobenzophenone, bis (2-methoxy-4-hydroxy) -5-benzoylphenylmethane), (2,4-bis- (n-octylthio) -6- (4-hydroxy-3,5-di-tert-butylanilino) -1,3,5-triazine, 2 (2 '-Hydroxy-3', 5'-di-tert-butylphenyl) -5-chlorobenzotriazole, (2 (2'-hydroxy-3 ', 5'-di-tert-amylphenyl) -5-chlorobenzo Triazole, 2,6-di-tert-butyl-p-cresol, pentaerythrityl-tetrakis [3- (3,5-di tert-butyl-4-hydroxyphenyl) propionate], triethylene glycol-bis [3- (3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate], 1,6-hexanediol-bis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], 2,4-bis- (n-octylthio) -6- (4-hydroxy-3,5-di-tert-butylanilino) -1 , 3,5-triazine, 2,2-thio-diethylenebis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], octadecyl-3- (3,5-di-tert- Butyl-4-hydroxyphenyl) propionate, N, N′-hexamethylenebis (3,5-di-tert-butyl-4- Hydroxy-hydrocinnamide), 1,3,5-trimethyl-2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene, tris- (3,5-di-tert-butyl) -4-hydroxybenzyl) -isocyanurate and the like. In particular, (2,4-bis- (n-octylthio) -6- (4-hydroxy-3,5-di-tert-butylanilino) -1,3,5-triazine, 2 (2′-hydroxy-3 ′, 5'-di-tert-butylphenyl) -5-chlorobenzotriazole, (2 (2'-hydroxy-3 ', 5'-di-tert-amylphenyl) -5-chlorobenzotriazole, 2,6-di -Tert-butyl-p-cresol, pentaerythrityl-tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], triethylene glycol-bis [3- (3-tert-butyl -5-methyl-4-hydroxyphenyl) propionate], for example, N, N'-bis [3- (3,5-di-tert-butyl-4 Hydroxyphenyl) may be used in combination with phosphorus-based processing stabilizer such as metal hydrazine systems such as propionyl] hydrazine deactivator and tris (2,4-di -tert- butylphenyl) phosphite.

  An ultraviolet absorber can also be introduce | transduced into resin as a structural unit which has an ultraviolet absorptivity. For example, a benzotriazole derivative, a triazine derivative or a benzophenone derivative into which a polymerizable group is introduced. The polymerizable group to be introduced can be appropriately selected according to the structural unit of the resin.

  Specific examples of the monomer having ultraviolet absorbing ability include 2- (2′-hydroxy-5′-methacryloyloxy) ethylphenyl-2H-benzotriazole (manufactured by Otsuka Chemical Co., Ltd., trade name RUVA-93), 2- (2 '-Hydroxy-5'-methacryloyloxy) phenyl-2H-benzotriazole, 2- (2'-hydroxy-3'-t-butyl-5'-methacryloyloxy) phenyl-2H-benzotriazole.

(Other additives)
To the base film, additives such as a matting agent, a retardation developer, a plasticizer, an ultraviolet absorber, a deterioration preventing agent, a release agent, an infrared absorber, and a wavelength dispersion adjusting agent can be added. However, it may be an oily substance. That is, the melting point and boiling point are not particularly limited. For example, mixing of ultraviolet absorbing material at 20 ° C. or lower and 20 ° C. or higher, and similarly mixing of a plasticizer is described in, for example, JP-A-2001-151901. Furthermore, infrared absorbing dyes are described in, for example, JP-A No. 2001-194522. Moreover, the addition time may be added at any time in the dope preparation step, but may be added by adding an additive to the final preparation step of the dope preparation step. Furthermore, the amount of each material added is not particularly limited as long as the function is manifested. Moreover, when an optical film is formed from a multilayer, the kind and addition amount of the additive of each layer may differ. For example, it is described in Japanese Patent Application Laid-Open No. 2001-151902, and these are conventionally known techniques. For these details, materials described in detail on pages 16 to 22 in the Japan Institute of Invention Disclosure Technical Bulletin (Public Technical No. 2001-1745, published on March 15, 2001, Japan Institute of Invention) are preferably used.

  The base film may contain rubber-like particles. Examples thereof include acrylic particles such as soft acrylic resin, acrylic rubber, and rubber-acrylic graft type core-shell polymer, or styrene-elastomer copolymer. Furthermore, additives that improve impact resistance and stress whitening resistance described in JP-B-60-17406, JP-B-3-39095 and the like are also preferably used.

In the said base film, when adding these additives, it is preferable that the total amount of an additive is 50 mass% or less with respect to a base film, and it is preferable that it is 30 mass% or less.
These additives improve the brittleness of the film and greatly improve the folding resistance test of the film (e.g., crack evaluation when bent 180 degrees).
In order to achieve low haze, the refractive index of the additive preferably has substantially the same refractive index as the base polymer, and the refractive index difference is preferably 0.5 or less, more preferably 0.3 or less. preferable.

<Characteristics of base film>
(Retardation)
In the substrate film, Re and Rth (defined by the following formulas (I ′) and (II ′)) measured at a wavelength of 590 nm preferably satisfy the formulas (III ′) and (IV ′).
Formula (I ′) Re = (nx−ny) × d
Formula (II ′) Rth = {(nx + ny) / 2−nz} × d
Formula (III ′) | Re | ≦ 50 nm
Formula (IV ′) | Rth | ≦ 300 nm
(In the formulas (I ′) to (IV ′), nx is the refractive index in the slow axis direction in the film plane of the base film, and ny is in the fast axis direction in the film plane of the base film. (It is a refractive index, nz is the refractive index in the film thickness direction of the base film, and d is the thickness (nm) of the base film.)
In the base film, the above formulas (III ′) and (IV ′) may be satisfied at at least one point in the film plane, but the above formulas (III ′) and (IV) may be satisfied at any point in the film plane. It is preferable that (IV ′) is satisfied.

In this specification, Re, Rth, and Nz at a wavelength λnm can be measured as follows.
Re is measured with KOBRA 21ADH (manufactured by Oji Scientific Instruments Co., Ltd.) by making light of wavelength λ nm incident in the normal direction of the film.
Rth was measured by making light having a wavelength λ nm incident from a direction inclined + 40 ° with respect to the normal direction of the film with the slow axis in the plane (determined by KOBRA 21ADH) as the tilt axis (rotation axis). A retardation value and a retardation value measured by making light of wavelength λ nm incident from a direction inclined by −40 ° with respect to the film normal direction with the in-plane slow axis as the tilt axis (rotation axis). Calculated by KOBRA 21ADH based on the retardation value measured in the direction. Here, as the assumed value of the average refractive index, values in the thermoplastic handbook (John Wiley & Sons, Inc.) and catalogs of various optical films can be used. Those whose average refractive index is not known can be measured with an Abbe refractometer. The average refractive index values of main optical films are exemplified below: cellulose acylate (1.48), cycloolefin thermoplasticity (1.52), polycarbonate (1.59), polymethyl methacrylate (1.49) Polystyrene (1.59).
In the measurement of the base film, when the thermoplastic resin used for the base film is a cellulose ester, the average refractive index of the base film is 1.48 and the retardation is measured.

  The Re and Rth are the types of the thermoplastic resin used for the base film (if the thermoplastic resin used for the base film is a cellulose ester, the degree of substitution of the cellulose ester), the thermoplastic resin And the amount of the additive, addition of the retardation enhancer, film thickness of the film, stretching direction and stretching ratio of the film, and the like.

(Base film thickness)
The film thickness of the substrate film is preferably 5 to 100 μm, more preferably 10 to 80 μm, particularly preferably 15 to 70 μm, and particularly preferably 20 to 60 μm. By controlling the film thickness within the above range, it is possible to reduce the unevenness of the panel due to the environment where the liquid crystal display device is placed after laminating the low moisture permeable layer, that is, the temperature and humidity change.

(Water vapor permeability of base film)
The moisture permeability of the base film is measured under the conditions of 40 ° C. and 90% relative humidity based on JIS Z-0208.
The moisture permeability of the base film is preferably 300 g / m ² / day or less.
More preferably, it is 50 g / m ² / day or less, further preferably 200 g / m ² / day or less, and particularly preferably 150 g / m ² / day or less. By controlling the moisture permeability of the base film within the above range, the liquid crystal display device equipped with the optical film (the optical film of the present invention) on which the low moisture permeable layer is mounted is subjected to normal temperature, high humidity, and high temperature and high humidity environment over time. In addition, warping of the liquid crystal cell and display unevenness during black display can be suppressed.

(Moisture permeability per unit film thickness of base film)
As described in the description of (moisture permeability per unit film thickness) of the low moisture permeability layer, the moisture permeability is given to the substrate 10 μm by the following equation.
C _s (10 μm) = J _s × d _s / 10 [g / m ² / day]
(Here, d _s [μm] is the film thickness of the base film, and J _s is the moisture permeability of the base film.)
Moisture permeability is preferably 50~2000g ^/ m 2 ^/ day film thickness of the substrate film for 10 [mu] m, more preferably 80~1500g ^/ m 2 ^/ day, more preferably 100~1000g ^/ m 2 ^/ day, 150~800g / M ² / day is particularly preferred. (The moisture permeability is the value after 24 hours at 40 ° C. and 90% relative humidity by the method of JIS 0208.)
Further, the moisture permeability C _b (10 μm) / C _s (10 μm) of the base film and the low moisture permeable layer having a film thickness of 10 μm is preferably 1.5 to 30, more preferably 2 to 20. 3 to 10 is particularly preferable.
A sufficient low moisture permeability effect is obtained above the lower limit, and curling can be suppressed below the upper limit.

(Oxygen permeability coefficient of base film)
In order to reduce moisture permeability, it is preferable to suppress the diffusion of water in the film, that is, it is preferable to reduce the free volume of the film. In general, the free volume of the film correlates with the oxygen permeability coefficient of the film.
The oxygen permeability coefficient of the base film is preferably 100 cc · mm / (m ² · day · atm) or less, and more preferably 30 cc · mm / (m ² · day · atm) or less.
The oxygen permeability coefficient of the base film can be measured by the following method.

<Measurement method of oxygen permeability coefficient>
The oxygen permeation amount of the film was measured by attaching a test piece cut to a diameter of 1.5 cm through silicon grease thinly applied to an oxygen electrode (MODEL3600, PFA manufactured by Orbis Fair Laboratories), and reducing the oxygen reduction current in a steady state. From the output value, the oxygen transmission amount was determined.
Conversion of the output current value to the oxygen permeation amount was obtained by creating a calibration curve using a sample with a known permeation amount. The measurement was performed in an environment of 25 ° C. and 50% RH.

(Haze of base film)
The base film preferably has a total haze value of 2.00% or less. When the total haze value is 2.00% or less, the transparency of the film is high, and the contrast ratio and brightness of the liquid crystal display device are improved. The total haze value is more preferably 1.00% or less, further preferably 0.50% or less, particularly preferably 0.30% or less, and most preferably 0.20% or less. The lower the total haze value, the better the optical performance, but it is preferably 0.01% or more considering raw material selection, production control, and roll film handling.
The internal haze value of the substrate film is preferably 1.00% or less. By setting the internal haze value to 1.00% or less, the contrast ratio of the liquid crystal display device can be improved and excellent display characteristics can be realized. The internal haze value is more preferably 0.50% or less, further preferably 0.20% or less, particularly preferably 0.10% or less, and most preferably 0.05% or less. From the viewpoint of raw material selection, production control, etc., 0.01% or more is preferable.
In particular, the base film preferably has a total haze value of 0.30% or less and an internal haze value of 0.10% or less.
The total haze value and internal haze value are the types and addition amounts of film materials, selection of additives (particularly the particle size, refractive index, addition amount of matting agent particles), and further film production conditions (temperature at stretching, The stretching ratio can be adjusted.
In addition, the measurement of a haze can be measured according to JISK-6714 with a haze meter (HGM-2DP, Suga test machine) at 25 degreeC and 60% of relative humidity for the film sample 40 mm x 80 mm.

(Elastic modulus of base film)
The elastic modulus of the base film is preferably 1800 to 7000 MPa in the width direction (TD direction).
In the present invention, when the elastic modulus in the TD direction is within the above range, display unevenness at the time of black display after high humidity and high temperature and high humidity environment aging, transportability at the time of film production, end slit property and difficulty in breaking. It is preferable from the viewpoint of manufacturing suitability. If the TD elastic modulus is too small, display unevenness at the time of black display after high humidity and high temperature and high humidity environment is likely to occur, and there is a problem in manufacturing suitability. The elastic modulus is more preferably 1800 to 5000 MPa, and further preferably 1800 to 4000 MPa.
Moreover, 1800-4000 MPa is preferable and, as for the elasticity modulus of the conveyance direction (MD direction) of the said base film, it is more preferable that it is 1800-3000 MPa.
Here, the conveyance direction (longitudinal direction) of the film is the conveyance direction (MD direction) during film production, and the width direction is the direction (TD direction) perpendicular to the conveyance direction during film production.
The elastic modulus of the film depends on the type and amount of the thermoplastic resin used in the base film material, selection of additives (particularly, the particle size, refractive index, and amount of addition of the matting agent particles), and film production conditions (stretching). The magnification can be adjusted.
The elastic modulus is obtained, for example, by measuring a stress at 0.5% elongation at a tensile rate of 10% / min in an atmosphere of 23 ° C. and 70 RH% using a universal tensile tester “STM T50BP” manufactured by Toyo Baldwin Co., Ltd. be able to.

(Glass transition temperature Tg of base film)
The glass transition temperature Tg of the base film is preferably 100 ° C. or higher and 200 ° C. or lower, more preferably 100 ° C. or higher and 150 ° C. or lower, from the viewpoints of production suitability and heat resistance.
The glass transition temperature is a temperature at which the base line derived from the glass transition of the film starts to change and a temperature at which it returns to the base line again when measured at a heating rate of 10 ° C./min using a differential scanning calorimeter (DSC). It can be calculated as an average value.
Moreover, the measurement of a glass transition temperature can also be calculated | required using the following dynamic viscoelasticity measuring apparatuses. A film sample (unstretched) 5 mm × 30 mm was conditioned at 25 ° C. and 60% RH for 2 hours or more, and then grasped with a dynamic viscoelasticity measuring device (Vibron: DVA-225 (produced by IT Measurement Control Co., Ltd.)) Measured at a distance of 20 mm, a temperature increase rate of 2 ° C./min, a measurement temperature range of 30 ° C. to 250 ° C., and a frequency of 1 Hz. The straight line 1 and the straight line when a straight line 1 is drawn in the solid region and a straight line 2 is drawn in the glass transition region, when the storage elastic modulus sometimes shifts from the solid region to the glass transition region. The intersection of 2 is the temperature at which the storage elastic modulus suddenly decreases and the film begins to soften when the temperature rises, and is the temperature at which the film begins to move to the glass transition region.

(Knoop hardness of the base film)
The polarizing plate protective film used for the outermost surface preferably has a high surface hardness. In that case, as a characteristic of the base film, it is preferable that the Knoop hardness is high. The Knoop hardness is preferably 100 N / mm ² or more, more preferably 150 N / mm ² or more.
The Knoop hardness of the base film can be measured by the following method.

<Measurement of surface hardness>
Using the “Fuscherscope H100Vp hardness tester” manufactured by Fischer Instruments Co., Ltd., the direction of the minor axis of the indenter is relative to the transport direction (longitudinal direction; test direction in the pencil hardness test) when the cellulose acylate film is formed. The surface of the sample fixed to the glass substrate was measured with a Knoop indenter arranged in parallel under a load time of 10 sec, a creep time of 5 sec, an unload time of 10 sec, and a maximum load of 100 mN. The hardness was calculated from the relationship between the contact area between the indenter and the sample obtained from the indentation depth and the maximum load, and the average value of these five points was defined as the surface hardness.

(Equilibrium moisture content of base film)
The water content (equilibrium water content) of the base film is 25, regardless of the film thickness, so as not to impair the adhesiveness with water-soluble thermoplastics such as polyvinyl alcohol when used as a protective film for a polarizing plate. It is preferable that the moisture content in 0 degreeC and 80% of relative humidity is 0-4 mass%. It is more preferably 0 to 2.5% by mass, and still more preferably 0 to 1.5% by mass. If the equilibrium moisture content is 4% by mass or less, the dependence of retardation on humidity changes does not become too large, and the display unevenness of the liquid crystal display device during black display after normal temperature, high humidity, and high temperature and high humidity environments is suppressed. This is also preferable.
The moisture content was measured by measuring a film sample 7 mm × 35 mm by a Karl Fischer method using a moisture measuring device and sample drying apparatuses “CA-03” and “VA-05” (both manufactured by Mitsubishi Chemical Corporation). It can be calculated by dividing the amount of water (g) by the sample mass (g).

(Dimensional change of base film)
The dimensional stability of the base film is as follows: dimensional change rate after standing for 24 hours under conditions of 60 ° C. and 90% relative humidity (high humidity), and 80 ° C., DRY environment (relative humidity 5% or less) ) When it is allowed to stand for 24 hours under the above conditions (high temperature), it is preferable that the dimensional change rate is 0.5% or less. More preferably, it is 0.3% or less, More preferably, it is 0.15% or less.

(Photoelastic coefficient of base film)
When the optical film of the present invention is used as a protective film for a polarizing plate, birefringence (Re, Rth) may change due to stress caused by the contraction of the polarizer. Although the change in birefringence accompanying such stress can be measured as a photoelastic coefficient, the elastic modulus of the base film is preferably 15 Br or less, more preferably −3 to 12 Br, and more preferably 0 to 11 Br. More preferably it is.

<Method for producing base film>
Hereinafter, a manufacturing method for forming a thermoplastic resin film mainly composed of a (meth) acrylic polymer used in the present invention will be described in detail.
In order to form a base film using a (meth) acrylic polymer as a main component, for example, after pre-blending the film raw material with a conventionally known mixer such as an omni mixer, the resulting mixture is extrusion kneaded. To do. In this case, the mixer used for extrusion kneading is not particularly limited. For example, a conventionally known mixer such as an extruder such as a single screw extruder or a twin screw extruder or a pressure kneader can be used. .

  Examples of the film forming method include conventionally known film forming methods such as a solution casting method (solution casting method), a melt extrusion method, a calendar method, and a compression molding method. Of these film forming methods, the melt extrusion method is particularly suitable.

  Examples of the melt extrusion method include a T-die method and an inflation method, and the molding temperature at that time may be appropriately adjusted according to the glass transition temperature of the film raw material, and is not particularly limited. For example, it is preferably 150 ° C to 350 ° C, more preferably 200 ° C to 300 ° C.

  When forming a film by the T-die method, a roll-shaped film can be obtained by attaching a T-die to the tip of a known single-screw extruder or twin-screw extruder and winding the film extruded into a film. it can. At this time, it is possible to perform uniaxial stretching by appropriately adjusting the temperature of the take-up roll and adding stretching in the extrusion direction. Further, simultaneous biaxial stretching, sequential biaxial stretching, and the like can be performed by stretching the film in a direction perpendicular to the extrusion direction.

  The base film having the (meth) acrylic polymer as the main component may be either an unstretched film or a stretched film. In the case of a stretched film, either a uniaxially stretched film or a biaxially stretched film may be used. When it is a biaxially stretched film, either a simultaneous biaxially stretched film or a sequential biaxially stretched film may be used. In the case of biaxial stretching, the mechanical strength is improved and the film performance is improved. When the (meth) acrylic polymer is a (meth) acrylic polymer having a cyclic structure in the main chain, mixing with other thermoplastic resins increases the retardation even when stretched. It is possible to obtain a film that can be suppressed and retains optical isotropy.

  The stretching temperature is preferably in the vicinity of the glass transition temperature of the (meth) acrylic polymer that is the film raw material, specifically, preferably (glass transition temperature-30 ° C) to (glass transition temperature + 100 ° C), More preferably, it is within the range of (glass transition temperature−20 ° C.) to (glass transition temperature + 80 ° C.). If the stretching temperature is less than (glass transition temperature-30 ° C.), a sufficient stretching ratio may not be obtained. Conversely, when the stretching temperature exceeds (glass transition temperature + 100 ° C.), the flow of the (meth) acrylic polymer may occur, and stable stretching may not be performed.

  The draw ratio is preferably 1.1 to 25 times, more preferably 5.0 to 20 times in terms of area ratio, and particularly preferably 8 to 15 times. If the draw ratio is less than 1.1 times, the toughness accompanying the drawing may not be improved. On the other hand, when the draw ratio exceeds 25 times, the effect of increasing the draw ratio may not be recognized. Moreover, when the draw ratio is 5 times or more, moisture permeability may be lowered in addition to improvement of toughness, which is more preferable in the present invention.

  The stretching speed is unidirectional, preferably 10 to 20,000% / min, more preferably 100 to 10,000% / min. When the stretching speed is less than 10% / min, it takes time to obtain a sufficient stretching ratio, and the production cost may increase. On the contrary, when the stretching speed exceeds 20,000% / min, the stretched film may be broken.

  In addition, the base film obtained by using the (meth) acrylic polymer as a main component can be subjected to a heat treatment (annealing) or the like after the stretching treatment in order to stabilize its optical isotropy and mechanical properties. . The conditions for the heat treatment may be appropriately selected similarly to the conditions for the heat treatment performed on a conventionally known stretched film, and are not particularly limited.

  The thickness of the base film obtained with the (meth) acrylic polymer as a main component is preferably 5 μm to 200 μm, more preferably 10 μm to 100 μm. When the thickness is less than 5 μm, not only the strength of the film is lowered, but also when the durability test is performed by sticking to other parts, the crimp may be increased. On the other hand, when the thickness exceeds 200 μm, not only the transparency of the film is lowered, but also the moisture permeability is reduced, and when a water-based adhesive is used when sticking to other parts, water that is the solvent is used. The drying speed may be slow.

(surface treatment)
The base film may be optionally surface-treated to achieve improved adhesion between the base film and the low moisture permeable layer or other layers (for example, a polarizer, an undercoat layer, and a back layer). it can. For example, glow discharge treatment, ultraviolet irradiation treatment, corona treatment, flame treatment, acid or alkali treatment can be used. The glow discharge treatment here may be low-temperature plasma that occurs under a low pressure gas of 10 ^{−3 to} 20 Torr, and plasma treatment under atmospheric pressure is also preferred. A plasma-excitable gas is a gas that is plasma-excited under the above conditions, and includes chlorofluorocarbons such as argon, helium, neon, krypton, xenon, nitrogen, carbon dioxide, tetrafluoromethane, and mixtures thereof. It is done. Details of these are described in detail in pages 30 to 32 in the Japan Institute of Invention Disclosure Technical Bulletin (Public Technical Number 2001-1745, published on March 15, 2001, Japan Institute of Invention), and are preferably used in the present invention. be able to.

{Function layer}
Moreover, although the optical film of this invention has the said low moisture-permeable layer, you may laminate | stack a functional layer further on at least one surface. The type of the functional layer is not particularly limited, but a hard coat layer, an antireflection layer (a layer having a adjusted refractive index such as a low refractive index layer, a medium refractive index layer, or a high refractive index layer), an antiglare layer, an antistatic layer, Examples include an ultraviolet absorbing layer.
The functional layer may be a single layer or a plurality of layers. The method for laminating the functional layer is not particularly limited, but it is preferable to coat another functional layer on the optical film of the present invention after laminating the low moisture-permeable layer.
The functional layer may be laminated on the surface of the base film provided with the low moisture permeable layer. In this case, the functional layer may or may not be in contact with the low moisture permeable layer. Moreover, you may laminate | stack on the surface which has not laminated | stacked the low moisture-permeable layer. When laminating a plurality of functional layers, one functional layer can be laminated on the low moisture-permeable layer, and another functional layer can be laminated on the surface where the low moisture-permeable layer is not laminated.

[Layer structure of optical film]
The optical film of the present invention preferably has a low moisture permeability layer on one surface of the base film, is a polarizing plate protective film, and is a surface film of a liquid crystal display device. When the optical film of the present invention is a surface film, it is preferable that a hard coat layer is laminated. A preferred layer structure in this case is shown below.

Base film / Low moisture permeability layer / Hard coat layer Base film / Hard coat layer / Low moisture permeability layer Low moisture permeability layer / Base film / Hard coat layer Base film / Low moisture permeability layer / Hard coat layer / Reflection Prevention layer Base film / hard coat layer / low moisture permeability layer / antireflection layer Low moisture permeability layer / base film / hard coat layer / antireflection layer Base film / low moisture permeability layer / hard coat layer / antireflection layer / Anti-fouling layer

[Hard coat layer]
As described above, the optical film of the present invention is preferably provided with a hard coat layer as a functional layer.
In the present invention, the hard coat layer refers to a layer in which the pencil hardness of the transparent support is increased by forming the layer. Practically, the pencil hardness (JIS K5400) after laminating the hard coat layer is preferably H or higher, more preferably 2H or higher, and most preferably 3H or higher.
The thickness of the hard coat layer is preferably 0.4 to 35 μm, more preferably 1 to 30 μm, and most preferably 1.5 to 20 μm.
In the present invention, the hard coat layer may be a single layer or a plurality of layers. When there are a plurality of hard coat layers, it is preferable that the total film thickness of all the hard coat layers is in the upper range.
The surface of the hard coat layer of the optical film of the present invention may be flat and uneven. Further, if necessary, the hard coat layer may contain translucent particles for imparting surface irregularities and internal scattering.

[Hard coat layer forming material]
In the present invention, the hard coat layer comprises a composition containing an unsaturated double bond, a polymerization initiator, and, if necessary, translucent particles, a fluorine-containing or silicone compound, and a solvent on a support. It can be formed by coating, drying and curing directly or through another layer. Each component will be described below.

[Compound having an unsaturated double bond]
The composition for forming a hard coat layer of the present invention can contain a compound having an unsaturated double bond. The compound having an unsaturated double bond can function as a binder, and is preferably a polyfunctional monomer having two or more polymerizable unsaturated groups. The polyfunctional monomer having two or more polymerizable unsaturated groups can function as a curing agent, and can improve the strength and scratch resistance of the coating film. The number of polymerizable unsaturated groups is more preferably 3 or more. These monomers can be used in combination of a monofunctional or bifunctional monomer and a trifunctional or higher monomer.

Examples of the compound having an unsaturated double bond include compounds having a polymerizable functional group such as a (meth) acryloyl group, a vinyl group, a styryl group, and an allyl group. Among them, a (meth) acryloyl group and —C (O ) OCH = CH ₂ is preferred. Particularly preferably, a compound containing three or more (meth) acryloyl groups in one molecule described below can be used.

  Specific examples of the compound having a polymerizable unsaturated bond include (meth) acrylic acid diesters of alkylene glycol, (meth) acrylic acid diesters of polyoxyalkylene glycol, and (meth) acrylic acid diesters of polyhydric alcohol. , (Meth) acrylic acid diesters of ethylene oxide or propylene oxide adducts, epoxy (meth) acrylates, urethane (meth) acrylates, polyester (meth) acrylates, and the like.

  Among these, esters of polyhydric alcohol and (meth) acrylic acid are preferable. For example, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol (meth) acrylate, ethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate , Pentaerythritol tetra (meth) acrylate, pentaerythritol tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, EO modified trimethylolpropane tri (meth) acrylate, PO modified trimethylolpropane tri (meth) acrylate, EO modified Tri (meth) acrylate phosphate, trimethylolethane tri (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, dipentaerythritol tetra (meth) acrylate Rate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, 1,2,3-cyclohexanetetramethacrylate, polyurethane polyacrylate, polyester polyacrylate, caprolactone-modified tris (acryloxyethyl) isocyanurate, etc. Can be mentioned.

  Commercially available polyfunctional acrylate compounds having a (meth) acryloyl group can be used, such as NK ester A-TMMT manufactured by Shin-Nakamura Chemical Co., Ltd., KAYARAD DPHA manufactured by Nippon Kayaku Co., Ltd. Can be mentioned. The polyfunctional monomer is described in paragraphs [0114] to [0122] of JP-A-2009-98658, and the same applies to the present invention.

  The compound having an unsaturated double bond is preferably a compound having a hydrogen-bonding substituent from the viewpoint of adhesion to the support, low curl, and fluorine-containing or silicone-based compound fixation described later. . The hydrogen-bonding substituent refers to a substituent in which an atom having a large electronegativity such as nitrogen, oxygen, sulfur, or halogen and a hydrogen bond are covalently bonded. Specifically, OH—, SH—, — NH-, CHO-, CHN- and the like can be mentioned, and urethane (meth) acrylates and (meth) acrylates having a hydroxyl group are preferable. Commercially available polyfunctional acrylates having a (meth) acryloyl group can also be used. Shin Nakamura Chemical Co., Ltd. NK Oligo U4HA, NK Ester A-TMM-3, Nippon Kayaku Co., Ltd. KAYARAD PET-30 etc. can be mentioned.

  The content of the compound having an unsaturated double bond in the composition for forming a hard coat layer of the present invention provides a sufficient polymerization rate and imparts hardness and the like, so that the inorganic component in the composition for forming a hard coat layer 50 mass% or more is preferable with respect to the total solid content except, 60-99 mass% is more preferable, 70-99 mass% is still more preferable, 80-99 mass% is especially preferable.

In the present invention, it is also preferable to use a compound having a cyclic aliphatic hydrocarbon and an unsaturated double bond group in the molecule for the composition for forming a hard coat layer. By using such a compound, low moisture permeability can be imparted to the hard coat layer. In order to enhance the hard coat property, it is more preferable to use a compound having two or more cyclic aliphatic hydrocarbons and unsaturated double bond groups in the molecule.
When the composition for forming a hard coat layer contains a compound having a cyclic aliphatic hydrocarbon and an unsaturated double bond group in the molecule, the compound having a cyclic aliphatic hydrocarbon and an unsaturated double bond in the molecule is hard. 1-90 mass% is preferable in the compound which has an unsaturated double bond in the composition for coat layer formation, 2-80 mass% is more preferable, 5-70 mass% is especially preferable.

When the composition for forming a hard coat layer contains a compound having a cyclic aliphatic hydrocarbon and an unsaturated double bond group in the molecule, it preferably further contains a (meth) acrylate having 5 or more functional groups.
When the hard coat layer forming composition further contains a pentafunctional or higher (meth) acrylate, the pentafunctional or higher (meth) acrylate is a compound having an unsaturated double bond in the hard coat layer forming composition. Among them, 1 to 70% by mass is preferable, 2 to 60% by mass is more preferable, and 5 to 50% by mass is particularly preferable.

[Translucent particles]
By including translucent particles in the hard coat layer of the present invention, it is possible to impart an uneven shape to the hard coat layer surface or to impart internal haze.

  Translucent particles that can be used in the hard coat layer include 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), cross-linked polystyrene particles (refractive index 1.61), polyvinyl chloride particles (refractive index 1.60), Examples include benzoguanamine-melamine formaldehyde particles (refractive index 1.68), silica particles (refractive index 1.46), alumina particles (refractive index 1.63), zirconia particles, titania particles, or particles having hollow or pores. It is done.

  Of these, crosslinked poly ((meth) acrylate) particles and crosslinked poly (acryl-styrene) particles are preferably used, and the refractive index of the binder is adjusted according to the refractive index of each light-transmitting particle selected from these particles. By adjusting, surface irregularities, surface haze, internal haze, and total haze suitable for the hard coat layer of the optical film of the present invention can be achieved.

The refractive index of the binder (translucent resin) is preferably 1.45 to 1.70, more preferably 1.48 to 1.65.
Further, the difference in refractive index between the translucent particles and the binder of the hard coat layer (“refractive index of the translucent particles” − “refractive index of the hard coat layer excluding the translucent particles”) is an absolute value. As for it, Preferably it is less than 0.05, More preferably, it is 0.001-0.030, More preferably, it is 0.001-0.020. When the difference in refractive index between the light-transmitting particles and the binder in the hard coat layer is less than 0.05, the light refraction angle by the light-transmitting particles decreases, the scattered light does not spread to a wide angle, and the optical anisotropy There is no adverse effect such as depolarization of the transmitted light of the layer, which is preferable.

In order to realize the difference in refractive index between the particles and the binder, the refractive index of the light-transmitting particles may be adjusted, or the refractive index of the binder may be adjusted.
As a preferable first embodiment, a binder having a tri- or higher functional (meth) acrylate monomer as a main component (a refractive index after curing is 1.50 to 1.53) and an acrylic content of 50 to 100 mass percent is used. It is preferable to use a combination of translucent particles made of poly (meth) acrylate / styrene polymer. By adjusting the composition ratio of the acrylic component having a low refractive index and the styrene component having a high refractive index, it is easy to make the difference in refractive index between the translucent particles and the binder less than 0.05. The ratio of the acrylic component to the styrene component is preferably 50/50 to 100/0, more preferably 60/40 to 100/0, and most preferably 65/35 to 90/10 in terms of mass ratio. The refractive index of the light-transmitting particles comprising the crosslinked poly (meth) acrylate / styrene polymer is preferably 1.49 to 1.55, more preferably 1.50 to 1.54, and most preferably 1. 51 to 1.53.
As a preferred second embodiment, a binder composed of a monomer and inorganic fine particles is obtained by using inorganic fine particles having an average particle size of 1 to 100 nm in combination with a binder mainly composed of a tri- or higher functional (meth) acrylate monomer. The refractive index difference is adjusted to adjust the refractive index difference from the existing light-transmitting particles. As the inorganic particles, an oxide of at least one metal selected from silicon, zirconium, titanium, aluminum, indium, zinc, tin, and antimony, specific examples include SiO ₂ , ZrO ₂ , TiO ₂ , Al ₂ O. ₃ , In ₂ O ₃ , ZnO, SnO ₂ , Sb ₂ O ₃ , ITO and the like. _Preferably, such _{SiO 2, ZrO 2, Al 2} O 3 and the like. These inorganic particles can be used by mixing in the range of 1 to 90% by mass with respect to the total amount of monomers, and preferably 5 to 65% by mass.
Here, the refractive index of the hard coat layer excluding the translucent particles can be quantitatively evaluated by directly measuring 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.

  The average particle diameter of the translucent particles is preferably 1.0 to 12 μm, more preferably 3.0 to 12 μm, still more preferably 4.0 to 10.0 μm, and most preferably 4.5 to 8 μm. By setting the refractive index difference and the particle size within the above ranges, the light scattering angle distribution does not spread to a wide angle, and it is difficult to cause blurring of characters on the display and a decrease in contrast. It is not necessary to increase the thickness of the layer to be added, and 12 μm or less is preferable because it is difficult to cause problems such as curling and cost increase. Furthermore, it is preferable that the amount falls within the above range from the viewpoint that the coating amount during coating can be suppressed, drying is quick, and surface defects such as drying unevenness are unlikely to occur.

  The measuring method of the average particle diameter of the translucent particles can be any measuring method as long as it is a measuring method for measuring the average particle diameter of the particles, but preferably a transmission electron microscope (magnification of 500,000 to 2,000,000 times) The particles are observed by observing 100 particles, and the average value can be obtained as the average particle diameter.

  The shape of the translucent particles is not particularly limited, but in addition to the spherical particles, translucent particles having different shapes such as irregularly shaped particles (for example, non-spherical particles) may be used in combination. In particular, when the minor axes of non-spherical particles are aligned in the normal direction of the hard coat layer, particles having a smaller particle diameter than the true spherical particles can be used.

  The translucent particles are preferably blended so as to be contained in an amount of 0.1 to 40% by mass in the total solid content of the hard coat layer. More preferably, it is 1-30 mass%, More preferably, it is 1-20 mass%. The internal haze can be controlled within a preferable range by adjusting the blending ratio of the translucent particles within the above range.

Moreover, the application amount of translucent particles is preferably 10 to 2500 mg / m ² , more preferably 30 to 2000 mg / m ² , and still more preferably 100 to 1500 mg / m ² .

<Translucent particle preparation, classification method>
Examples of the method for producing the translucent particles 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 any method may be used. These production methods are described in, for example, “Experimental Methods for Polymer Synthesis” (Takayuki Otsu and Masaaki Kinoshita, Chemical Dojinsha), pages 130 and 146 to 147, “Synthetic Polymers”, Vol. 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 terms of haze value and diffusibility control, and uniformity of the coated surface. The CV value representing the uniformity of the particle diameter is preferably 15% or less, more preferably 13% or less, and still more preferably 10% or less. Further, when a particle having a particle size of 20% or more than the average particle size is defined as a coarse particle, the proportion of the coarse particle is preferably 1% or less of the total number of particles, more preferably 0.1% or less. Yes, more preferably 0.01% or less. Particles having such a particle size distribution are also effective means of classification after preparation or synthesis reaction, and particles having a desired 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.

[Photopolymerization initiator]
The hard coat layer forming composition preferably contains a photopolymerization initiator. The photopolymerization initiator described for the low moisture-permeable layer can also be preferably used in the composition for forming a hard coat layer.

  The content of the photopolymerization initiator in the composition for forming the hard coat layer is sufficiently high to polymerize the polymerizable compound contained in the composition for forming the hard coat layer and is small enough not to increase the starting point excessively. From the reason that the amount is set, the amount is preferably 0.5 to 8% by mass, and more preferably 1 to 5% by mass with respect to the total solid content in the composition for forming a hard coat layer.

[Ultraviolet absorber]
The optical film of the present invention is used for a polarizing plate or a liquid crystal display device member, but from the viewpoint of preventing deterioration of the polarizing plate or liquid crystal, the hard coat layer contains an ultraviolet absorber in a range that does not inhibit UV curing. Thus, ultraviolet absorption can be imparted to the optical film.

[solvent]
The composition for forming a hard coat layer of the present invention can contain a solvent. Various solvents can be used as the solvent in consideration of the solubility of the monomer, the dispersibility of the light-transmitting particles, the drying property at the time of coating, and the like. Examples of such organic solvents include dibutyl ether, dimethoxyethane, diethoxyethane, propylene oxide, 1,4-dioxane, 1,3-dioxolane, 1,3,5-trioxane, tetrahydrofuran, anisole, phenetole, dimethyl carbonate, carbonic acid. Methyl ethyl, diethyl carbonate, acetone, methyl ethyl ketone (MEK), diethyl ketone, dipropyl ketone, diisobutyl ketone, cyclopentanone, cyclohexanone, methylcyclohexanone, ethyl formate, propyl formate, pentyl formate, methyl acetate, ethyl acetate, propyl acetate, Methyl propionate, ethyl propionate, γ-ptyrolactone, methyl 2-methoxyacetate, methyl 2-ethoxyacetate, ethyl 2-ethoxyacetate, ethyl 2-ethoxypropionate, 2-metho Siethanol, 2-propoxyethanol, 2-butoxyethanol, 1,2-diacetoxyacetone, acetylacetone, diacetone alcohol, methyl acetoacetate, methyl acetoacetate and other methyl alcohol, ethyl alcohol, isopropyl alcohol, n-butyl alcohol, cyclohexyl Alcohol, isobutyl acetate, methyl isobutyl ketone (MIBK), 2-octanone, 2-pentanone, 2-hexanone, ethylene glycol ethyl ether, ethylene glycol isopropyl ether, ethylene glycol butyl ether, propylene glycol methyl ether, ethyl carbitol, butyl carbitol , Hexane, heptane, octane, cyclohexane, methylcyclohexane, ethylcyclohexane, benzene, tolu Examples thereof include ene and xylene, and these can be used alone or in combination of two or more.

  It is preferable to use a solvent so that the solid content of the composition for forming a hard coat layer of the present invention is in the range of 20 to 80% by mass, more preferably 30 to 75% by mass, and still more preferably 40 to 40% by mass. 70% by mass.

[Antireflection layer]
As described above, laminating the antireflection layer on the hard coat layer is one of the preferred embodiments of the present invention. In the present invention, a known antireflection layer can be preferably used. Among them, a UV curable antireflection layer is preferable.
The antireflection layer may be a low-reflectance layer having a single-layer thickness of λ / 4 or a multi-layer structure, but a low-reflectance layer having a single-layer thickness of λ / 4 is particularly preferable. The low refractive material that can be preferably used in the present invention will be described below, but the present invention is not limited thereto.

[Material for low refractive index layer]
The material for the low refractive index layer will be described below.

[Inorganic fine particles]
From the viewpoint of lowering the refractive index and improving the scratch resistance, it is preferable to use inorganic fine particles in the low refractive index layer. The inorganic fine particles are not particularly limited as long as the average particle size is 5 to 120 nm, but inorganic low refractive index particles are preferable from the viewpoint of lowering the refractive index.

  Examples of the inorganic fine particles include magnesium fluoride and silica fine particles because of their low refractive index. In particular, silica fine particles are preferable in terms of refractive index, dispersion stability, and cost. The size (primary particle size) of these inorganic particles is preferably 5 to 120 nm, more preferably 10 to 100 nm, 20 to 100 nm, and most preferably 30 to 90 nm.

  If the particle size of the inorganic fine particles is too small, the effect of improving the scratch resistance is reduced. If the particle size is too large, fine irregularities are formed on the surface of the low refractive index layer, and the appearance such as black tightening and the integrated reflectance are deteriorated. Further, when hollow silica fine particles described later are used, if the particle size is too small, the ratio of the cavity portion is reduced and a sufficient decrease in the refractive index cannot be expected. 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 may be indefinite.

The coating amount of the inorganic fine particles is ^{preferably 1mg / m 2 ~100mg / m 2} , more preferably ^{5mg / m 2 ~80mg / m 2} , more preferably from ^{10mg / m 2 ~60mg / m 2} . If the amount is too small, a sufficiently low refractive index cannot be expected or the effect of improving the scratch resistance is reduced. If the amount is too large, fine irregularities are formed on the surface of the low refractive index layer, and the appearance and integration such as black tightening Reflectivity deteriorates.

(Porous or hollow fine particles)
In order to reduce the refractive index, it is preferable to use fine particles having a porous or hollow structure. It is particularly preferable to use hollow structure silica particles. The porosity of these particles is preferably 10 to 80%, more preferably 20 to 60%, and most preferably 30 to 60%. It is preferable that the void ratio of the hollow fine particles be in the above range from the viewpoint of lowering the refractive index and maintaining the durability of the particles.

  When the porous or hollow particles are silica, the refractive index of the fine particles is preferably 1.10 to 1.40, more preferably 1.15 to 1.35, and most preferably 1.15 to 1.30. is there. The refractive index here represents the refractive index of the entire particle, and does not represent the refractive index of only the outer shell silica forming the silica particles.

  Further, two or more kinds of hollow silica having different particle average particle sizes can be used in combination. Here, the average particle diameter of the hollow silica can be determined from an electron micrograph.

The specific surface area of the hollow silica in the present invention is preferably from 20 to 300 m ² / g, more preferably 30~120m ² / g, most preferably 40~90m ² / g. The surface area can be determined by the BET method using nitrogen.

  In the present invention, silica particles having no voids can be used in combination with hollow silica. The preferred particle size of silica without voids is 30 nm to 150 nm, more preferably 35 nm to 100 nm, and most preferably 40 nm to 80 nm.

[Inorganic fine particle surface treatment method]
Further, in the present invention, inorganic fine particles can be used after being surface-treated with a silane coupling agent or the like by a conventional method.
In particular, in order to improve dispersibility in the binder for forming a low refractive index layer, the surface of the inorganic fine particles is preferably treated with a hydrolyzate of an organosilane compound and / or a partial condensate thereof. In this case, it is more preferable to use either an acid catalyst or a metal chelate compound or both. The method for treating the surface of the inorganic fine particles is described in paragraphs [0046] to [0076] of JP-A-2008-242314, and the organosilane compound, the siloxane compound, and the solvent for the surface treatment described in the document. Surface treatment catalysts, metal chelate compounds, and the like can also be suitably used in the present invention.

For the low refractive index layer, (b2) a fluorine-containing or non-fluorine-containing monomer having a polymerizable unsaturated group can be used. As the non-fluorinated monomer, it is preferable to use a compound having an unsaturated double bond described as being usable in the hard coat layer. As the fluorine-containing monomer, a fluorine-containing polyfunctional monomer (d) represented by the following general formula (1), containing 35% by mass or more of fluorine and having a calculated value of all cross-linking molecular weights smaller than 500 is used. Is preferred.
General formula (1): Rf ² {-(L) _m -Y} _n
(In General Formula (1), Rf ² represents an n-valent group containing at least a carbon atom and a fluorine atom, n represents an integer of 3 or more, L represents a single bond or a divalent linking group, and m represents Represents 0 or 1. Y represents a polymerizable unsaturated group.)
Rf ² may contain at least one of an oxygen atom and a hydrogen atom. Further, Rf ² is a chain (straight or branched) or cyclic.

Y is preferably a group containing two carbon atoms forming an unsaturated bond, more preferably a radical polymerizable group, a (meth) acryloyl group, an allyl group, an α-fluoroacryloyl group, and Those selected from —C (O) OCH═CH ₂ are particularly preferred. Among these, from the viewpoint of polymerizability, (meth) acryloyl group, allyl group, α-fluoroacryloyl group, and C (O) OCH═CH ₂ having radical polymerizability are more preferable.

L represents a divalent linking group, specifically, an alkylene group having 1 to 10 carbon atoms, an arylene group having 6 to 10 carbon atoms, -O-, -S-, -N (R)-, 1 to carbon atoms. A group obtained by combining 10 alkylene group and —O—, —S— or N (R) —, a combination of an arylene group having 6 to 10 carbon atoms and —O—, —S— or N (R) —. Represents the resulting group. R represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. When L represents an alkylene group or an arylene group, the alkylene group and the arylene group represented by L are preferably substituted with a halogen atom, and preferably substituted with a fluorine atom.
Specific examples of the compound represented by the general formula (1) are described in paragraphs [0121] to [0163] of JP 2010-152111 A.

[Optically anisotropic layer]
An optically anisotropic layer can also be provided on the optical film of the present invention. The optically anisotropic layer may be an optically anisotropic layer in which a film having a constant retardation is uniformly formed in the plane, and the direction of the slow axis and the magnitude of the retardation are different from each other. It may be an optically anisotropic layer having a pattern in which retardation regions are regularly arranged in a plane.
As described above, the optical film of the present invention is preferably a surface film on which a hard coat layer of a liquid crystal display device is laminated. When the optical film of the present invention has both a hard coat layer and an optically anisotropic layer, the optically anisotropic layer is preferably formed on a surface on which the hard coat layer is not laminated via a base film. .

When the optical film of the present invention has such an embodiment, the low moisture permeable layer may be laminated on the same side as the hard coat layer with respect to the base film, or provided on the opposite side to the hard coat layer. It may be laminated | stacked on both surfaces of the base film.
A preferable layer configuration in the case where the low moisture-permeable layer is laminated on the same side as the hard coat layer with respect to the base film can be a preferred layer configuration in the case of laminating the hard coat layer.
On the other hand, when the low moisture permeable layer is laminated on the same side as the optically anisotropic layer with respect to the base film, the low moisture permeable layer may be laminated between the base film and the optically anisotropic layer. Alternatively, the base film, the optically anisotropic layer, and the low moisture permeable layer may be laminated in this order.

  The optically anisotropic layer can be selected from materials and production conditions according to various uses, but in the present invention, an optically anisotropic layer using a polymerizable liquid crystalline compound is preferable. In that case, it is also a preferred embodiment that an alignment film is formed between the optically anisotropic layer and the substrate film in contact with the optically anisotropic layer.

  A preferred example having an optically anisotropic layer formed uniformly in the plane is an embodiment in which the optically anisotropic layer is a λ / 4 film, and is particularly useful as a member of an active 3D liquid crystal display device. As an aspect in which a λ / 4 film's anisotropy layer and a hard coat layer are laminated on opposite surfaces via a base film, they are described in JP2012-098772A and JP20121277982A. Such an embodiment can be preferably used in the optical film of the present invention.

  On the other hand, as a preferable example of the optically anisotropic layer in which a pattern is formed, a pattern type λ / 4 film is exemplified, and the embodiments described in Japanese Patent Nos. 4825934 and 4887463 are applied to the optical film of the present invention. It can be preferably used.

[Polarizer]
The polarizing plate of the present invention includes a polarizer and at least one optical film of the present invention as a protective film for the polarizer.
The optical film of the present invention can be used as a protective film for a polarizing plate. When using as a protective film for polarizing plates, the production method of a polarizing plate is not specifically limited, It can produce by a general method. There is a method in which the obtained optical film is treated with an alkali and bonded to both sides of a polarizer prepared by immersing and stretching a polyvinyl alcohol film in an iodine solution using a completely saponified polyvinyl alcohol aqueous solution. Instead of alkali treatment, easy adhesion processing as described in JP-A-6-94915 and JP-A-6-118232 may be performed. Further, the surface treatment as described above may be performed. The bonding surface of the optical film with the polarizer may be a surface laminated with a low moisture permeable layer or a surface not laminated with a low moisture permeable layer.
Examples of the adhesive used to bond the protective film treated surface and the polarizer include polyvinyl alcohol adhesives such as polyvinyl alcohol and polyvinyl butyral, vinyl latexes such as butyl acrylate, and the like.
The polarizing plate is composed of a polarizer and a protective film that protects both surfaces of the polarizer, and further includes a protective film bonded to one surface of the polarizing plate and a separate film bonded to the other surface. The protective film and the separate film are used for the purpose of protecting the polarizing plate at the time of shipping the polarizing plate and at the time of product inspection. In this case, the protect film is bonded for the purpose of protecting the surface of the polarizing plate, and is used on the side opposite to the surface where the polarizing plate is bonded to the liquid crystal plate. Moreover, a separate film is used in order to cover the adhesive layer bonded to a liquid crystal plate, and is used for the surface side which bonds a polarizing plate to a liquid crystal plate.

[Liquid Crystal Display]
The liquid crystal display device of the present invention includes a liquid crystal cell and the polarizing plate of the present invention disposed in at least one of the liquid crystal cells, so that the optical film of the present invention contained in the polarizing plate is the outermost layer. It is arranged.

(General liquid crystal display device configuration)
The liquid crystal display device includes a liquid crystal cell having a liquid crystal supported between two electrode substrates, two polarizing plates disposed on both sides thereof, and, if necessary, between the liquid crystal cell and the polarizing plate. At least one optical compensation film is arranged.
The liquid crystal layer of the liquid crystal cell is usually formed by sealing liquid crystal in a space formed by sandwiching a spacer between two substrates. The transparent electrode layer is formed on the substrate as a transparent film containing a conductive substance. The liquid crystal cell may further be provided with a gas barrier layer, a hard coat layer, or an undercoat layer (undercoat layer) (used for adhesion of the transparent electrode layer). These layers are usually provided on the substrate. The substrate of the liquid crystal cell generally has a thickness of 50 μm to 2 mm.

In a liquid crystal display device, a substrate including a liquid crystal cell is usually disposed between two polarizing plates. The protective film for polarizing plates to which the optical film of the present invention is applied is a protective film for any of the two polarizing plates. Although it can be used, it is preferable to use as a protective film arrange | positioned outside a liquid crystal cell with respect to a polarizer among two protective films of each polarizing plate.
Of the two polarizing plates, it is particularly preferable to dispose the optical film of the present invention as a viewing-side protective film of the viewing-side polarizing plate.
Moreover, after arranging the optical film of the present invention as the protective film on the viewing side of the viewing side polarizing plate of the two polarizing plates, the present invention is also applied to the backlight side protective film of the backlight side polarizing plate. It is also a preferable aspect to dispose an optical film, suppress expansion and contraction of the polarizer contained in the two polarizing plates, and prevent warping of the panel.

(Types of liquid crystal display devices)
The film of the present invention can be used for liquid crystal cells in various display modes. TN (Twisted Nematic), IPS (In-Plane Switching), FLC (Ferroelectric Liquid Crystal), AFLC (Anti-Ferroly Liquid Liquid Crystal), OCB (Optically QuantNW). Various display modes such as ECB (Electrically Controlled Birefringence) and HAN (Hybrid Aligned Nematic) have been proposed. In addition, a display mode in which the above display mode is oriented and divided has been proposed. The optical film of the present invention is effective in any display mode liquid crystal display device. Further, it is effective in any of a transmissive type, a reflective type, and a transflective liquid crystal display device.

  Hereinafter, the present invention will be specifically described based on examples. The materials, reagents, amounts and ratios of substances, operations, and the like shown in the following examples can be appropriately changed without departing from the gist of the present invention. Therefore, the present invention is not limited to the following examples.

[Production Example 1]
<Preparation of base film 1>
In a reaction vessel having an internal volume of 30 L equipped with a stirrer, a temperature sensor, a cooling pipe and a nitrogen introduction pipe, 8000 g of methyl methacrylate (MMA), 2000 g of methyl 2- (hydroxymethyl) acrylate (MHMA) and 10000 g of toluene as a polymerization solvent Was heated up to 105 ° C. while passing nitrogen through it. When the reflux accompanying the temperature rise began, 10.0 g of t-amylperoxyisonononanoate was added as a polymerization initiator, and a solution comprising 20.0 g of t-amylperoxyisonononanoate and 100 g of toluene was added. While dropping over time, solution polymerization was allowed to proceed under reflux at about 105 to 110 ° C., and further aging was performed for 4 hours. The polymerization reaction rate was 96.6%, and the content (mass ratio) of MHMA in the obtained polymer was 20.0%.

  Next, 10 g of stearyl phosphate / distearyl phosphate mixture (Phoslex A-18, manufactured by Sakai Chemical Industry Co., Ltd.) as a cyclization catalyst is added to the resulting polymerization solution, and the mixture is refluxed at about 80 to 100 ° C. for 5 hours. The cyclization condensation reaction was allowed to proceed.

  Next, the obtained polymerization solution was subjected to a barrel type screw twin screw extruder having a barrel temperature of 260 ° C., a rotation speed of 100 rpm, a degree of vacuum of 13.3 to 400 hPa (10 to 300 mmHg), a rear vent number of 1, and a forevent number of 4. (Φ = 29.75 mm, L / D = 30) was introduced at a treatment rate of 2.0 kg / hour in terms of resin amount, and cyclization condensation reaction and devolatilization were performed in the extruder. Next, after completion of devolatilization, the resin in the molten state left in the extruder is discharged from the tip of the extruder, pelletized by a pelletizer, and transparent pellets made of an acrylic resin having a lactone ring structure in the main chain A was obtained. The weight average molecular weight of this resin is 148,000, the melt flow rate (based on JIS K7120, the test temperature is 240 ° C., the load is 10 kg, the same applies to the following production examples) is 11.0 g / 10 min, glass transition The temperature was 130 ° C.

  Next, the obtained pellets and AS resin (made by Toyo Styrene, trade name: Toyo AS AS20) are kneaded using a single screw extruder (φ = 30 mm) at a mass ratio of pellet / AS resin = 90/10. As a result, a transparent pellet B having a glass transition temperature of 127 ° C. was obtained.

  The resin composition pellet B produced above was melt extruded from a coat hanger type T die using a twin screw extruder to produce a resin film having a thickness of about 160 μm.

  Next, the obtained unstretched resin film is biaxially stretched 2.0 times in the longitudinal direction and 2.0 times in the transverse direction (stretching ratio is 4 times in area ratio), thereby producing a transparent plastic film base. A material was prepared. The biaxially stretchable film thus obtained had a thickness of 40 μm, a total light transmittance of 92%, a haze of 0.3%, and a glass transition temperature of 127 ° C.

[Production Example 2]
<Preparation of base film 2>
The resin composition pellets B produced above were melt extruded from a coat hanger type T die using a twin screw extruder to produce a resin film having a thickness of about 500 μm.

  Next, the obtained unstretched resin film is biaxially stretched 3.4 times in the longitudinal direction and 3.6 times in the transverse direction (stretching ratio is 12.2 times in terms of area ratio). A film substrate was prepared. The biaxially stretchable film thus obtained had a thickness of 40 μm, a total light transmittance of 92%, a haze of 0.3%, and a glass transition temperature of 127 ° C.

[Production Example 3]
<Preparation of base film 3>
In a reaction vessel having an internal volume of 30 L equipped with a stirrer, a temperature sensor, a cooling pipe and a nitrogen introduction pipe, 41.5 parts of methyl methacrylate (MMA) and 6 parts of methyl 2- (hydroxymethyl) acrylate (MHMA) 2.5 parts of 2- [2′-hydroxy-5′-methacryloyloxy] ethylphenyl] -2H-benzotriazole (trade name: RUVA-93, manufactured by Otsuka Chemical), 50 parts of toluene as a polymerization solvent, 0 0.025 part of an antioxidant (manufactured by Asahi Denka Kogyo Co., Ltd., Adeka Stub 2112) and 0.025 part of n-dodecyl mercaptan were charged as a chain transfer agent, and the temperature was raised to 105 ° C. through nitrogen. When the reflux with the temperature increase started, 0.05 part of t-amyl peroxyisononanoate (manufactured by Arkema Yoshitomi, trade name: Luperox 570) was added as a polymerization initiator, and 0.10 part of t- While amyl peroxy isononanoate was added dropwise over 3 hours, solution polymerization was allowed to proceed under reflux at about 105 to 110 ° C., followed by further aging for 4 hours.

  Next, 0.05 part of 2-ethylhexyl phosphate (manufactured by Sakai Chemical Industry Co., Ltd., Phoslex A-8) is added to the resulting polymerization solution as a catalyst for the cyclization condensation reaction (cyclization catalyst). The cyclization condensation reaction was allowed to proceed for 2 hours under reflux at 0 ° C., and then the polymerization solution was heated for 30 minutes in an autoclave at 240 ° C. to further proceed the cyclization condensation reaction. Next, 0.94 parts of CGL777MPA (manufactured by Ciba Specialty Chemicals) was mixed with the polymerization solution after the reaction proceeded as an ultraviolet absorber.

Next, the obtained polymerization solution was subjected to a barrel temperature of 240 ° C., a rotation speed of 100 rpm, a degree of vacuum of 13.3 to 400 hPa (10 to 300 mmHg), a rear vent number of 1 and a forevent number of 4 (first and 2, third and fourth vents), a vent type screw twin screw extruder (Φ = 50.0 mm) in which a leaf disk type polymer filter (filtration accuracy 5 μ, filtration area 1.5 m ² ) is arranged at the tip. L / D = 30) was introduced at a treatment rate of 45 kg / hr in terms of resin amount, and devolatilization was performed. At that time, a separately prepared mixed solution of antioxidant / cyclization catalyst deactivator was charged at a rate of 0.68 kg / hour from the back of the first vent, and ion-exchanged water was charged at 0.22 kg / hour. Each was fed from behind the third vent at a speed.

  In the mixed solution of antioxidant / cyclization catalyst deactivator, 50 parts of antioxidant (Sumitizer GS manufactured by Sumitomo Chemical Co., Ltd.) and 35 parts of zinc octylate (manufactured by Nippon Kagaku Sangyo Co., Ltd., Nikka Octix) Zinc (3.6%) was dissolved in 200 parts of toluene.

  Next, after completion of devolatilization, the resin in the hot melt state remaining in the extruder is discharged while being filtered through a polymer filter from the tip of the extruder, pelletized by a pelletizer, and has a lactone ring structure in the main chain A transparent resin composition pellet C containing an acrylic resin and an ultraviolet absorber was obtained. The weight average molecular weight of the resin was 145000, and the glass transition temperature (Tg) of the resin and the resin composition was 122 ° C.

  The resin composition pellets C produced above were melt-extruded from a coat hanger type T die using a twin screw extruder to produce a resin film having a thickness of about 160 μm.

Next, the obtained unstretched resin film is biaxially stretched 2.0 times in the longitudinal direction and 2.0 times in the transverse direction (stretching ratio is 4 times in area ratio), thereby producing a transparent plastic film base. A material was prepared.
When the physical properties of the biaxially stretchable resin film thus obtained were measured, the thickness was 40 mm, the haze (turbidity) was 0.3%, the glass transition temperature was 128 ° C., and the transmittance for light at 380 nm was The transmittance for light of 5.8% and 500 nm was 92.2%.

[Production Example 4]
[Preparation of composition for forming a low moisture-permeable layer]
Prepared as shown below.

(Composition of composition B-1 for forming a low moisture-permeable layer)
A-DCP (100%) 97.0 g
Irgacure 907 (100%) 3.0g
SP-13 0.04g
MEK 81.8g

[Production Example 5]
(Composition of composition B-2 for forming a low moisture permeable layer)
AA-BPEF (100%) 97.0 g
Irgacure 907 (100%) 3.0g
SP-13 0.04g
MEK 81.8g

[Production Example 6]
(Composition of composition B-3 for forming a low moisture permeable layer)
PET30 (100%) 97.0g
Irgacure 907 (100%) 3.0g
SP-13 0.04g
MEK 81.8g

The materials used are shown below.
A-DCP: tricyclodecane dimethanol dimethacrylate [manufactured by Shin-Nakamura Chemical Co., Ltd.]
AA-BPEF: 9, 9-bis [4- (2acryloyloxyethoxy) phenyl] fluorene [manufactured by Shin-Nakamura Chemical Co., Ltd.]
PET30: A mixture of pentaerythritol tetraacrylate and pentaerythritol triacrylate [manufactured by Nippon Kayaku Co., Ltd.]
・ Irgacure 907: Polymerization initiator [Ciba Specialty Chemicals Co., Ltd.]
・ Leveling agent

・ SP-13:

<Preparation of optical film 101>
As a base film, Fujitac TD80 (manufactured by Fuji Film Co., Ltd., width 1,340 mm, thickness 80 μm) is unwound from the roll form, and the low moisture-permeable layer forming composition B-1 is used. In the die coating method using the slot die described in Example 1 of JP-A-122889, the coating was performed under the condition of a conveyance speed of 30 m / min and dried at 60 ° C. for 150 seconds. Thereafter, using an air-cooled metal halide lamp (manufactured by Eye Graphics Co., Ltd.) with an oxygen concentration of about 0.1% under a nitrogen purge, ultraviolet rays with an illuminance of 400 mW / cm ² and an irradiation amount of 60 mJ / cm ² are irradiated. Then, the coating layer was cured and wound up. The coating amount was adjusted so that the thickness of the low moisture-permeable layer was 5 μm.
The obtained optical film was designated as optical film 101.

<Preparation of optical films 102-116>
In the production of the optical film 101, the optical films 102 to 116 are the same as the optical film 101 except that the base film, the composition for forming a low moisture permeable layer, and the film thickness of the low moisture permeable layer are as described in the table. It was created.

[Evaluation of optical film]
The film thickness was measured about the produced optical film of each Example and a comparative example, and the following physical-property measurement and evaluation were performed. The results are shown in Table 1 below.
In addition, the film thickness of the low moisture-permeable layer measured the film thickness before and behind lamination | stacking of a low moisture-permeable layer, and calculated | required from the difference.

(1) Moisture permeability (moisture permeability at 40 ° C and 90% relative humidity)
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) The method described in is applied.
70 mmφ of optical film samples of each example and comparative example were conditioned at 40 ° C. and 90% relative humidity for 24 hours, respectively, and using a moisture permeable cup according to JIS Z-0208, moisture permeability = mass after humidity adjustment−control The amount of water per unit area (g / m ² ) was calculated by the mass before wetting. In this measurement, the moisture permeability value was corrected with a blank cup containing no hygroscopic agent.

[Panel Evaluation]
<Preparation of polarizing plate>
1) Saponification of Film Commercially available cellulose acylate film (Fujitack ZRD40, manufactured by Fuji Film Co., Ltd.) and optical films 101 to 104 are placed in a 1.5 mol / L NaOH aqueous solution (saponification solution) kept at 55 ° C. for 2 minutes. After dipping, the film was washed with water, then dipped in a 0.05 mol / L sulfuric acid aqueous solution at 25 ° C. for 30 seconds, and then a water washing bath was passed under running water for 30 seconds to make the film neutral. Then, draining with an air knife was repeated three times, and after dropping the water, the film was retained in a drying zone at 70 ° C. for 15 seconds and dried to produce a saponified film.

2) Production of Polarizer According to Example 1 of Japanese Patent Application Laid-Open No. 2001-141926, iodine was adsorbed to a stretched polyvinyl alcohol film to produce a polarizer having a thickness of 20 μm.

3) Bonding (production of polarizing plates 101 to 104)
Optical films 101 to 104 after saponification (arranged so that the surface on which the low moisture-permeable layer of each optical film is not laminated is in contact with the polarizer), the polarizer prepared above, and cellulose acylate after saponification The films ZRD40 were bonded in this order with a PVA adhesive and heat-dried to prepare polarizing plates 101 to 104.
Under the present circumstances, it arrange | positioned so that the longitudinal direction of the roll of the produced polarizer and the longitudinal direction of the optical films 101-104 may become parallel. Moreover, it arrange | positioned so that the longitudinal direction of the roll of a polarizer and the longitudinal direction of the roll of the said cell roll acylate film ZRD40 may become parallel.
The obtained polarizing plates 101-104 were made into the polarizing plates 101-104, respectively.

(Preparation of polarizing plates 105 to 116)
The surface where the low moisture-permeable layer of the produced optical films 105 to 114 is not laminated on one side of the polarizer produced as described above using the acrylic adhesive is the low moisture-permeable layer of the optical films 105 to 116. After the corona treatment was applied to the non-laminated surface, it was bonded. Using the polyvinyl alcohol adhesive on the other side of the polarizer prepared above, the saponified commercially available cellulose acylate film ZRD40 is pasted and dried at 70 ° C. for 10 minutes or more to produce polarizing plates 105 to 116. did.
Under the present circumstances, it arrange | positioned so that the longitudinal direction of the roll of the produced polarizer and the longitudinal direction of the optical films 105-116 may become parallel. Moreover, it arrange | positioned so that the longitudinal direction of the roll of a polarizer and the longitudinal direction of the roll of the said cell roll acylate film ZRD40 may become parallel.
The obtained polarizing plate was made into each polarizing plate 105-116.

(Preparation of polarizing plates 205-208)
The surface obtained by laminating the low moisture permeable layer of the produced optical films 105 to 108 using an acrylic adhesive was bonded to one side of the polarizer produced as described above, and then bonded. Using the polyvinyl alcohol adhesive on the other side of the polarizer prepared above, the above saponified commercially available cellulose acylate film ZRD40 is attached and dried at 70 ° C. for 10 minutes or more to produce polarizing plates 205 to 208. did.
Under the present circumstances, it arrange | positioned so that the longitudinal direction of the roll of the produced polarizer and the longitudinal direction of the optical films 105-108 may become parallel. Moreover, it arrange | positioned so that the longitudinal direction of the roll of a polarizer and the longitudinal direction of the roll of the said cell roll acylate film ZRD40 may become parallel.
The obtained polarizing plate was made into each polarizing plate 205-208.

<Implementation to IPS panel>
The upper and lower polarizing plates of the IPS mode liquid crystal cell (manufactured by LGD 42LS5600) were peeled off, and the polarizing plates 101 to 116 and 205 to 208 were attached so that the ZRD 40 was on the liquid crystal cell side. The crossed nicols were arranged so that the transmission axis of the upper polarizing plate was in the vertical direction and the transmission axis of the lower polarizing plate was in the horizontal direction.
The obtained liquid crystal display devices were designated as liquid crystal display devices 101 to 116 and 205 to 208, respectively.
In addition, the structure of the polarizing plate at the time of mounting on an IPS panel was described in Table 2 below.

  The liquid crystal display device produced as described above was evaluated for black display unevenness after a high temperature and high humidity environment. The results are shown in Tables 1 and 2 below.

(Black display unevenness after high temperature and high humidity environment)
The liquid crystal display device was allowed to pass for 36 hours at 60 ° C. and 90% relative humidity, then lit for 24 hours in an environment of 25 ° C. and 60% relative humidity, and then turned on to reduce the degree of color unevenness during black display. It observed visually and evaluated in six steps according to the following criteria.
Among the 6-step evaluation, A to D are within the allowable range, and E and F are outside the allowable range.
A to C are preferable, A or B is more preferable, and A is particularly preferable.
A: Color unevenness was not observed.
B: Weak color unevenness was observed in an area of 1/8 or less of the display surface.
C: Weak color unevenness was observed in an area of more than ¼ of the display surface and ¼ or less.
D: Weak color unevenness was observed in an area exceeding 1/4 of the display surface and 1/2 or less.
E: Strong color unevenness was observed in an area of more than 1/4 of the display surface and 1/2 or less.
F: Strong color unevenness was observed in an area exceeding 1/2 of the display surface.

From the results shown in Tables 1 and 2, the following is clear.
1. There is a strong correlation between the moisture permeability of the optical film and the display unevenness after the high temperature and high humidity environment, and the black display unevenness is suppressed as the moisture permeability is lower.
2. The embodiment of the present invention that satisfies the requirements of claim 1 is preferable because the film has a thin film thickness but low moisture permeability.
3. In the present invention, a composition having a compound having a cyclic aliphatic hydrocarbon group and an unsaturated double bond group in the molecule on a base film mainly composed of a (meth) acrylic copolymer resin having a lactone ring structure An optical film provided with a low moisture-permeable layer formed from a product is an example of a preferred embodiment of the present invention.
4). In the present invention, a base film mainly composed of a (meth) acrylic copolymer resin is stretched at a high magnification (5 times or more in terms of area), whereas a film with a low magnification (less than 5 times in terms of area) is stretched. The moisture permeability per unit film thickness is low, and the laminate with the low moisture permeable layer is good because the film thickness is thin and display unevenness after high temperature and high humidity environment aging is suppressed.
5. What provided the low moisture-permeable layer formed from the composition which has a compound which has a fluorene frame | skeleton and an unsaturated double bond group in a molecule | numerator is also an example of the preferable aspect of this invention.
6). The evaluation results when the optical film of the present invention is mounted on the panel are the same results as those obtained by pasting the opposite surface of the low moisture permeable layer to the polarizer and those obtained by pasting the low moisture permeable layer to the polarizer. was. Both sides of the optical film of the present invention can be bonded to a polarizer.

  Next, a hard coat layer is laminated on the optical film of the present invention.

[Production Example 7]
[Preparation of composition for forming hard coat layer]
Prepared as shown below.

(Composition of hard coat layer forming composition HC-1)
PET30 (100%) 97.0g
Irgacure 907 (100%) 3.0g
SP-13 0.04g
MEK 81.8g

[Production Example 8]
[Preparation of composition for forming hard coat layer]
Prepared as shown below.

(Composition of hard coat layer forming composition HC-2)
DPHA (100%) 48.5g
A-DCP (100%) 48.5g
Irgacure 907 (100%) 3.0g
SP-13 0.04g
MEK 81.8g

The materials used are shown below.
DPHA: Mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate [manufactured by Nippon Kayaku Co., Ltd.]
* Materials used for the low moisture permeability layer are omitted.

[Production Example 9]
<Preparation of hard coat film 301>
The roll-shaped optical film 105 created above is unwound from a roll form, and the low moisture-permeable layer forming composition HC-1 is used on the surface on which the low moisture-permeable layer is laminated. In the die coating method using the slot die described in Example 1 of US Pat. No. 122889, the coating was performed under the condition of a conveyance speed of 30 m / min and dried at 60 ° C. for 150 seconds. Thereafter, using an air-cooled metal halide lamp (manufactured by Eye Graphics Co., Ltd.) with an oxygen concentration of about 0.1% under a nitrogen purge, ultraviolet rays with an illuminance of 400 mW / cm ² and an irradiation amount of 300 mJ / cm ² are irradiated. Then, the coating layer was cured and wound up. The coating amount was adjusted so that the thickness of the low moisture permeable layer was 8 μm.
The obtained film was designated as a hard coat film 301.

<Production of hard coat films 302 to 306>
With respect to the hard coat film 301, the hard coat layer forming coating solution is changed as shown in Table 3 to form an optical film serving as a base film, and the hard coat layer is laminated on the low moisture permeable layer, and the hard coat film 302 to 306 was created.

<Preparation of hard coat film 307>
A hard coat film 307 is produced by laminating a hard coat layer on the opposite surface of the low moisture permeable layer in the same manner except that the hard coat layer laminated surface is changed to the opposite surface of the low moisture permeable layer. did.

<Preparation of hard coat films 308 to 309>
With respect to the hard coat film 301, the base material and the hard coat layer were changed as shown in Table 3, and the hard coat layer was laminated on the base material to prepare hard coat films 308 to 309.
The moisture permeability ratio (A / B) before and after the hard coat layer lamination of the hard coat film 309 is 0.75, which satisfies the formula (1).

<Preparation of hard coat film 310>
The substrate film-1 is unwound from the roll form, and transported by the die coat method using the slot die described in Example 1 of JP-A-2006-122889 using the hard coat layer forming composition HC-1. The coating was performed at a speed of 30 m / min and dried at 60 ° C. for 150 seconds. Thereafter, using an air-cooled metal halide lamp (manufactured by Eye Graphics Co., Ltd.) with an oxygen concentration of about 0.1% under a nitrogen purge, ultraviolet rays with an illuminance of 400 mW / cm ² and an irradiation amount of 60 mJ / cm ² are irradiated. Then, the coating layer was cured and wound up. The coating amount was adjusted so that the thickness of the hard coat layer was 8 μm.
Subsequently, the composition B-1 for forming a low moisture permeable layer was used, and was applied by a die coating method using a slot die described in Example 1 of Japanese Patent Application Laid-Open No. 2006-122889 at a conveyance speed of 30 m / min. Dry at 150 ° C. for 150 seconds. Thereafter, using an air-cooled metal halide lamp (manufactured by Eye Graphics Co., Ltd.) with an oxygen concentration of about 0.1% under a nitrogen purge, ultraviolet rays with an illuminance of 400 mW / cm ² and an irradiation amount of 300 mJ / cm ² are irradiated. Then, the coating layer was cured and wound up. The coating amount was adjusted so that the film thickness of the low moisture permeable layer was 3 μm, and a hard coat film 310 was prepared.

Polarizers 301 to 310 and liquid crystal display devices 301 to 310 were made from the hard coat films 301 to 310 in the same manner as the liquid crystal display device 105 was made from the optical film 105.
As with the liquid crystal display device 105, the liquid crystal display devices 301 to 310 were evaluated for black display unevenness after a high temperature and high humidity environment. The evaluation results are shown in Table 3.

[Evaluation of hard coat film]
The film thickness was measured about the produced optical film of each Example and a comparative example, and the following physical-property measurement and evaluation were performed. The results are shown in Table 3 below.
In addition, the film thickness of the hard coat layer of the hard coat films 301 to 310 was obtained from the difference between the film thicknesses measured before and after the hard coat layer was laminated. Moreover, the film thickness of the low moisture-permeable layer of the hard coat film 310 was obtained from the difference between the film thicknesses measured before and after the lamination of the low moisture-permeable layer.

(2) Pencil hardness evaluation Pencil hardness evaluation described in JIS K 5400 was performed as an index of scratch resistance. After conditioning the light diffusing film at a temperature of 25 ° C. and a humidity of 60% RH for 2 hours, using a 2H-5H test pencil specified in JIS S 6006 at a load of 4.9 N, as follows: Evaluation was made based on the judgment, and the highest hardness that gave OK was taken as the evaluation value.
OK: No less than 3 scratches in n = 5 evaluation NG: No more than 2 scratches in n = 5 evaluation

* The composition of each hard coat film is as follows: Hard coat films 301-306
Optical film / hard coat layer / low moisture permeable layer hard coat film 307
Low moisture permeable layer / optical film / hard coat layer hard coat film 308-309
Base film / hard coat layer hard coat film 310
Base film / hard coat layer / low moisture permeability layer

From the results shown in Table 3, the following is clear.
1. By laminating a hard coat layer on the optical film of the present invention, high pencil hardness (3H) can be imparted in addition to low moisture permeability.
2. A hard coat layer formed from a composition containing a compound having a cyclic aliphatic hydrocarbon group and an unsaturated polymerizable group in the molecule and a (meth) acrylate having 5 or more functional groups, formed from a (meth) acrylate polymer The coated film has a greater moisture permeability reduction effect than a film having a hard coat layer formed from a composition that does not contain a cyclic aliphatic hydrocarbon group and an unsaturated polymerizable group in the molecule.
3. A hard coat layer formed from a composition containing a compound having a cyclic aliphatic hydrocarbon group and an unsaturated polymerizable group in the molecule and a (meth) acrylate having 5 or more functional groups, formed from a (meth) acrylate polymer The coat film 309 satisfies the requirements of claim 1 of the present application.
4). A hard coat layer laminated on a low moisture permeable layer (hard coat film 302), a hard coat layer laminated on a low moisture permeable layer (hard coat film 310), and based on the hard coat layer and the low moisture permeable layer. Any of the materials (hard coat film 305) disposed on the opposite surface of the material has good pencil hardness and moisture permeability.

[Production Example 10]
(Preparation of coating solution Ln-1 for low refractive index layer)
Each component was mixed as described below and dissolved in a 90/10 mixture (mass ratio) of MEK / MMPG-AC to prepare a low refractive index layer coating solution having a solid content of 5% by mass.

(Composition of Ln-1)
15.0 g of the following perfluoroolefin copolymer (P-1)
DPHA 7.0g
RMS-033 5.0 g
20.0 g of the following fluorine-containing monomer (M-1)
Hollow silica particles (as solids) 50.0g
Irgacure 127 3.0g

  The compounds used are shown below.

Perfluoroolefin copolymer (P-1)

  In the above structural formula, 50:50 represents a molar ratio.

Fluorine-containing monomer (M-1)

DPHA: Mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate, manufactured by Nippon Kayaku Co., Ltd. RMS-033: Silicone polyfunctional acrylate (manufactured by Gelest, Mwt = 28000)
Irgacure 127: Photopolymerization initiator, manufactured by Ciba Specialty Chemicals Co., Ltd. Hollow silica: Hollow silica particle dispersion (average particle size 45 nm, refractive index 1.25, surface with silane coupling agent having acryloyl group) Surface treatment, MEK dispersion concentration 20%) ・ MEK: Methyl ethyl ketone ・ MMPG-Ac: Propylene glycol monomethyl ether acetate

  The coating solution for the low refractive index layer was filtered through a polypropylene filter having a pore size of 1 μm to prepare a coating solution. The refractive index after curing of the low refractive index layer obtained by coating and curing the coating liquid Ln-1 for low refractive index layer was 1.36.

(Preparation of antireflection film sample 506)
The roll-shaped optical film 106 produced in the same manner as described above was unwound from the roll form, and the coating liquid HC-1 for hard coat layer was used, and the slot die described in Example 1 of JP-A-2006-122889 was used. After coating with a die coating method at a conveyance speed of 30 m / min and drying at 60 ° C. for 150 seconds, an air-cooled metal halide lamp with an oxygen concentration of about 0.1% under a nitrogen purge (I Graphics Co., Ltd.) The coating layer was cured and wound by irradiating with ultraviolet rays having an illuminance of 600 mW / cm ² and an irradiation amount of 60 mJ / cm ² . The coating amount was adjusted so that the thickness of the hard coat layer was 8 μm.
Further, the hard coat film prepared above was unwound from the roll form, and the coating liquid Ln-1 for the low refractive index layer was applied to the side on which the hard coat layer was coated, to prepare an antireflection film sample 507. The low refractive index layer was dried at 60 ° C. for 60 seconds, and the ultraviolet curing condition was 240 W / cm air-cooled metal halide lamp (eye graphics) while purging with nitrogen so that the atmosphere had an oxygen concentration of 0.1% by volume or less. The irradiance was 600 mW / cm ² and the irradiation amount was 300 mJ / cm ² . The low refractive index layer had a refractive index of 1.36 and a film thickness of 95 nm.

In the antireflection film having the antireflection layer laminated as described above, the moisture permeability is low (65 g / m ² / day), the pencil hardness is high (3H), light leakage is difficult to place, and the reflectance is low (1. 1%), the image was less reflected when used in a liquid crystal display device. It is also a preferred embodiment that a hard coat layer and an antireflection layer are laminated on the optical film of the present invention.

Claims (17)

An optical film having a base film mainly composed of a (meth) acrylic polymer and a low moisture permeable layer laminated on the described film,
The optical film has a moisture permeability of 100 g / m ² / day or less,
An optical film characterized by satisfying the following formula (1).
Formula (1) 0.01 <= A / B <= 0.8
(In Formula (1), A represents the water vapor transmission rate of the optical film which laminated | stacked the said low moisture-permeable layer on the said base film, B represents the water vapor transmission rate of the said base film. However, a water vapor transmission rate is JIS 0208. (This is the value after 24 hours at 40 ° C. and 90% relative humidity.) Moisture permeability of the low moisture permeable layer when the thickness of the low moisture permeable layer is 10 μm J _b × d _b / 10
The optical film according to claim 1, wherein is 5.0 to 250 g / m ² / day.
(Here, d _b [μm] represents the film thickness of the low moisture-permeable layer, and is calculated from the film thickness difference before and after the lamination of the low moisture-permeable layer.
Further, J _b represents the moisture permeability of the low moisture-permeable layer when separating the optical film to the substrate and the low moisture-permeable layer, the moisture permeability J _s of the moisture permeability J _f, the substrate film of the optical _film, low the moisture permeability of the moisture-permeable layer is calculated from the following equation when a J _b. )
1 / J _f = 1 / J _s + 1 / J _b Expression (n)   The said (meth) acrylic-type polymer is a polymer which has either a lactone ring structure, a glutaric anhydride ring structure, or a glutarimide ring structure in a principal chain, The Claim 1 or Claim 2 characterized by the above-mentioned. Optical film. The optical film according to claim 3, wherein the (meth) acrylic polymer is a polymer having a unit represented by the following general formula (1).
General formula (1):

(Wherein R ¹¹ , R ¹² and R ¹³ each independently represents a hydrogen atom or an organic residue having 1 to 20 carbon atoms. The organic residue may contain an oxygen atom.)   The film thickness of the said base film is 5-80 micrometers, The optical film as described in any one of Claims 1-4 characterized by the above-mentioned.   The optical film according to claim 1, wherein a thickness of the low moisture-permeable layer is 1 to 12 μm.   The low moisture-permeable layer is a layer formed from a low moisture-permeable forming composition having a compound having a cyclic aliphatic hydrocarbon group and an unsaturated double bond group in the molecule. The optical film as described in any one of 1-6.   The low moisture-permeable layer is composed of a compound having a cyclic aliphatic hydrocarbon group and an unsaturated double bond group in the molecule with respect to the total solid content excluding inorganic components in the composition for forming a low moisture-permeable layer. The optical film according to claim 7, wherein the optical film is a layer formed from a composition containing ˜99% by mass.   The optical film according to any one of claims 1 to 8, wherein the optical film further has a hard coat layer.   The hard coat layer is a layer formed from a composition for forming a hard coat layer having a compound having a cyclic aliphatic hydrocarbon group and two or more unsaturated double bond groups in the molecule. The optical film according to any one of claims 1 to 9.   The optical film according to claim 10, wherein the composition for forming a hard coat layer further contains a (meth) acrylate having 5 or more functional groups.   The said low moisture-permeable layer is a layer formed from the composition for low moisture-permeability formation which has a compound which has a fluorene frame | skeleton and an unsaturated double bond group in a molecule | numerator. The optical film as described in any one.   The low moisture-permeable layer is a compound having a fluorene skeleton and an unsaturated double bond group in the molecule, based on the total solid content excluding the inorganic components in the composition for forming the low moisture-permeable layer, 60 to 99% by mass. The optical film according to claim 12, wherein the optical film is a layer formed from a composition containing the optical film.   The optical film according to any one of claims 1 to 13, wherein the base film is formed by melting a thermoplastic resin containing a (meth) acrylic polymer as a main component. A step of melt-forming a base film mainly composed of a (meth) acrylic polymer; and
The manufacturing method of the optical film which has a low moisture-permeable layer laminated | stacked on the base film including the process of laminating | stacking a low moisture-permeable layer on the said base film by application | coating. A polarizer,
A polarizing plate comprising at least one optical film according to any one of claims 1 to 14 as a protective film for the polarizer. A liquid crystal cell;
The polarizing plate according to claim 16 disposed in at least one of the liquid crystal cells,
A liquid crystal display device, wherein the optical film is arranged to be an outermost layer.