JP2013156391A - Manufacturing method of roll-shaped circularly polarizing plate, organic electroluminescence display device and lateral electric field type switching mode type liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide: a manufacturing method of a roll-shaped circularly polarizing plate to manufacture a circularly polarizing plate with high contrast and less unevenness of image and with excellent moisture-heat resistance; and an organic electroluminescence display device and a lateral electric field type switching mode type liquid crystal display device, using the roll-shaped circularly polarizing plate.SOLUTION: In a manufacturing method of a roll-shaped circularly polarizing plate to manufacture a roll-shaped circularly polarizing plate with a first protective film and a polarizer being laminated, the polarizer is made by laminating a hydrophilic polymer layer on a thermoplastic resin layer in a coating system and by stretching so as to have an inclination of 45° ±10° with respect to the conveyance direction. The manufacturing method of a roll-shaped circularly polarizing plate includes sticking the first protective film to the polarizer so that the in-plane phase value Ro of the first protective film is within the range of 80≤Ro≤200 and the angle between the slow axis of the first protective film and the absorption axis of the polarizer is 45° ±10°.

Description

  The present invention relates to a method for manufacturing a roll-shaped circularly polarizing plate using a polarizer having an absorption axis oblique to the longitudinal direction and the width direction, an organic electroluminescence display device, and a lateral electric field type switching mode liquid crystal display device.

  In recent years, the market for thin displays using liquid crystal displays and organic electroluminescence has grown rapidly. In particular, the market for small and medium-sized mobile devices called smartphones and pads is growing significantly.

  Small and medium-sized mobile devices are required to have thinner and lighter devices as well as to improve the contrast of displayed images. Therefore, the thinning of each member which comprises a display apparatus has become a big subject.

  In addition, a display device using organic electroluminescence has an optical element (λ / 4 polarizing plate) in which a polarizer and a λ / 4 retardation plate are combined, so that external light can be emitted from the light emitting element surface. It is known that reflection can be suppressed.

  Among the liquid crystal display methods, the horizontal electric field type switching mode type (hereinafter also referred to as in-plane switching method or IPS method) has a fast response speed, a wide viewing angle, and a high contrast in the oblique direction. It is preferably used as a medium-sized liquid crystal display. Medium and small-sized liquid crystal displays are frequently used outdoors. However, when polarized sunglasses are worn, image brightness changes depending on the viewing angle of the display, which is not preferable.

  It is known that the viewing angle can be widened by using a λ / 4 polarizing plate as a front polarizing plate of a liquid crystal display in response to the above problem.

  In addition, it is known that an active 3D display can expand the 3D viewing area by having an optical element (λ / 4 polarizing plate) in which a polarizer and a λ / 4 retardation plate are combined. Yes. For example, in order to suppress flicker of external light and improve the brightness of spectacles, a stereoscopic video display device using spectacles that uses only one polarizing plate has been disclosed (for example, see Patent Document 3). In this patent document, a circular polarizing plate is provided on the front surface of the display, and the configuration of the glasses is (λ / 4 plate) / (liquid crystal cell) / (linear polarizing plate), so that crosstalk when tilting the neck is achieved. It is disclosed that it can be suppressed.

  As a manufacturing method of the λ / 4 polarizing plate used in the above liquid crystal display, 1) a method of stretching a retardation film in an oblique direction and pasting it with a polarizer stretched in a longitudinal direction or a transverse direction; ) A method is known in which a polarizer is laminated in a sheet form with a retardation film stretched in the longitudinal direction or the width direction. In the former method, it is easy to break at the time of stretching the film, and it is very difficult to obtain a uniform film, and there is a disadvantage that the deterioration of contrast and display unevenness are remarkably inferior, and the latter has a lot of discarded parts at the time of punching, There was a disadvantage of being expensive.

  In addition, when a λ / 4 polarizing plate is arranged on the display, strong contraction force acts in the stretching direction of the polarizer and in the direction perpendicular to the stretching due to the influence of heat at the time of lighting the panel and humidity in the usage environment. Become. The shrinkage force to the polarizer increases from the center of the panel bonded to the polarizing plate according to the outside. However, when the polarizing plate absorption axis is arranged horizontally or vertically with respect to the liquid crystal panel, the four corners of the liquid crystal screen are displayed. As a result, deformation of the polarizing plate (curling due to expansion and contraction, etc.) causes polarization unevenness at the four corners of the liquid crystal screen, resulting in a significant problem that contrast is reduced over a wide range. What we have is the current situation.

  As one of the methods for solving the above problem, it is desired to reduce the thickness of the polarizer and the protective film which are constituent members. In response to this problem, a method of manufacturing a polarizing plate by applying a hydrophilic polymer to a substrate, stretching and dyeing the substrate is disclosed (for example, see Patent Document 1). According to the method described in Patent Document 1, a thin film polarizer can be formed. However, this method does not solve the contrast reduction of the λ / 4 polarizing plate.

  In addition, a method of stretching a polarizer obliquely is disclosed (for example, see Patent Document 2). However, with the method disclosed in Patent Document 2, a polarizer having an absorption axis in an oblique direction can be obtained, but it cannot meet the demand for thinning the polarizing plate, and in the state of a roll-shaped polarizing plate. The deterioration over time is large and has problems.

JP 2011-1000016 A JP 2011-22223 A JP 2002-82307 A

  The present invention has been made in view of the above problems, and a solution to the problem is a method for producing a rolled circularly polarizing plate that produces a circularly polarizing plate having high contrast, less image unevenness, and excellent wet heat durability, and It is another object of the present invention to provide an organic electroluminescence display device and a lateral electric field type switching mode liquid crystal display device using the roll-shaped circularly polarizing plate.

  As a result of diligent investigations in view of the above problems, the present inventor, as a roll-shaped circularly polarizing plate, roll-shaped circularly polarized light for producing a roll-shaped circularly polarizing plate in which at least a first protective film and a polarizer are laminated. In the method for producing a plate, the polarizer has a step of laminating a hydrophilic polymer layer on a thermoplastic resin layer by a coating method, and a step of stretching the polarizer so as to have an inclination of 45 ° ± 10 ° with respect to the transport direction. The in-plane phase value Ro of the first protective film is in the range of 80 to 200, and the angle formed by the slow axis of the first protective film and the absorption axis of the polarizer is By producing by the production method characterized by having a step of bonding the first protective film and the polarizer so as to be 45 ° ± 10 °, the image has high contrast, little unevenness of image, and wet heat Manufactures circularly polarizing plates with excellent durability It found that can Rukoto, is up which led to the present invention.

  That is, a hydrophilic polymer layer, such as polyvinyl alcohol, is formed on a thermoplastic resin layer as a base material to form a hydrophilic polymer layer, and the film is stretched obliquely with respect to the longitudinal direction. A transparent film (first protective film) having a phase difference such that an angle formed between a polarizer dyed with a substance, for example, iodine, and the slow axis and the absorption axis of the polarizer is 45 ° ± 10 °. By combining them, the reflection of external light on the light emitting element surface can be suppressed, high contrast can be obtained, an organic electroluminescence display device with little display unevenness, and an IPS type liquid crystal corresponding to the image viewing angle when wearing polarized sunglasses It has become possible to provide a thin circular polarizing plate compatible with displays at a low cost.

  That is, the above problem of the present invention is solved by the following means.

1. In the production method of a roll-shaped circularly polarizing plate for producing a roll-shaped circularly polarizing plate in which at least a first protective film and a polarizer are laminated,
The polarizer is produced by a step of laminating a hydrophilic polymer layer on a thermoplastic resin layer by a coating method and a step of stretching to have an inclination of 45 ° ± 10 ° with respect to the transport direction,
The in-plane phase value Ro of the first protective film satisfies the condition defined by the following formula (i),
And a step of bonding the first protective film and the polarizer so that an angle formed between the slow axis of the first protective film and the absorption axis of the polarizer is 45 ° ± 10 °. The manufacturing method of the roll-shaped circularly-polarizing plate characterized by the above-mentioned.

Formula (i)
80 ≦ Ro ≦ 200
Wherein is represented by _{Ro = (n x -n y)} × d, n x is a refractive index in a slow axis direction in a plane of the film, n _y is the direction perpendicular to the slow axis in the film plane Each represents a refractive index, and d represents the thickness (nm) of the film. Each refractive index is a value measured at an optical wavelength of 590 nm in an environment of a temperature of 23 ° C. and a relative humidity of 55% RH. ]
2. In the first item, the polarizer is stretched so as to have an inclination of 45 ° ± 10 ° with respect to the transport direction, and is contracted within a range of 10 to 40% in a direction perpendicular to the stretching axis. The manufacturing method of the roll-shaped circularly-polarizing plate of description.

  3. 3. The method for producing a roll-shaped circularly polarizing plate according to item 1 or 2, wherein the film thickness of the polarizer after stretching is in the range of 0.5 to 10 [mu] m.

  4). The stretching ratio for stretching the polarizer so as to have an inclination of 45 ° ± 10 ° with respect to the transport direction is in the range of 2.0 to 7.0 times, wherein the first to third items are characterized. The manufacturing method of the roll-shaped circularly-polarizing plate as described in any one of claim | items.

  5. Any one of Items 1 to 4, wherein the hydrophilic polymer layer forming the polarizer is a coated body of polyvinyl alcohol resin, and the dichroic material used in the dyeing step is an iodine-containing compound. The manufacturing method of the roll-shaped circularly-polarizing plate of one term.

  6). The roll according to any one of claims 1 to 5, further comprising a step of peeling the thermoplastic resin layer after bonding the first protective film and the polarizer. A method for producing a circularly polarizing plate.

  7). The first protective film includes a cellulose ester having an average acyl substitution degree of 1.5 to 2.7 and extending in a range of 1.05 to 1.50 times in the width direction or the longitudinal direction. The manufacturing method of the roll-shaped circularly-polarizing plate as described in any one of Claims 1-6 characterized by the above-mentioned.

  8). An organic electroluminescence display device comprising a circularly polarizing plate manufactured by the method for manufacturing a rolled circularly polarizing plate according to any one of items 1 to 7.

  9. A lateral electric field type switching mode type liquid crystal display device comprising a liquid crystal cell and two polarizing plates sandwiching the liquid crystal cell, wherein the roll according to any one of items 1 to 7 is provided on a viewing side of the liquid crystal cell. A transverse electric field type switching mode type liquid crystal display device, characterized in that a circularly polarizing plate manufactured by a method for manufacturing a circular circularly polarizing plate is disposed.

  It is presumed that the above problem can be solved by the configuration defined in the present invention for the following reason.

  As described above, the conventional circularly polarizing plate has been produced by a method in which a retardation film is stretched in an oblique direction and bonded to a polarizer stretched in a longitudinal direction or a transverse direction as described above. However, when the retardation film is stretched obliquely and has a large retardation (λ / 4), it is extremely difficult industrially to suppress in-plane variation of the retardation. That is, it is difficult to produce a uniform roll-shaped circularly polarizing plate with a retardation film stretched in an oblique direction. Also, in the method of stretching the polarizer diagonally, if the polarizer is a thick film, the dimensional variation due to heat and humidity is large, causing in-plane variations in the degree of polarization, and a stable circle against environmental variations. It was difficult to produce a polarizing plate.

  In the present invention, the retardation film is stretched in the longitudinal direction and the width direction, and the polarizer is a coating-type thin film polarizer, so that in-plane variation of retardation is suppressed and stable against environmental fluctuations. In addition, a circularly polarizing plate excellent in productivity could be produced. In addition, when the polarizer is produced by a coating method, particularly in the case of oblique stretching, there may be a case where minute peeling occurs at the interface due to the difference in elongation between the substrate and the polarizer, and stretching unevenness occurs. As a result of diligent investigation on the above problem, the present inventor has found that a more excellent circularly polarizing plate can be produced by providing a process of shrinking in a direction orthogonal to the stretching direction.

  In addition, when the circularly polarizing plate of the present invention is applied to a small and medium-sized mobile organic electroluminescence display device or a liquid crystal display, in recent years, the purpose of improving contrast and reducing the thickness by suppressing interface reflection on the surface of the polarizing plate Therefore, it is increasing that it is directly bonded to a display panel or a touch panel by OCA (optical transparent adhesive sheet) or OCR (optical transparent ultraviolet curable resin). By sticking with OCA or OCR, it becomes easy to transmit the heat of the backlight to the circularly polarizing plate. Therefore, the usefulness of the circularly polarizing plate of the present invention having high stability against environmental changes is enhanced.

  Further, when the punched circularly polarizing plate of the present invention is efficiently punched and disposed on the panel, the absorption axis of the polarizing plate is disposed diagonally with respect to the panel. Regarding the polarization unevenness at the four corners of the screen, the contraction force of the polarizer does not act on the four corners, so that the problem can be solved.

  As described above, a rolled circularly polarizing plate having high productivity and less unevenness and fluctuation has been provided.

  By the above-mentioned means of the present invention, a method for producing a rolled circularly polarizing plate for producing a circularly polarizing plate having high contrast, less image unevenness and excellent wet heat durability, and organic electroluminescence using the rolled circularly polarizing plate A display device and a horizontal electric field type switching mode liquid crystal display device can be provided.

The schematic diagram of the tenter which can be extended | stretched diagonally applicable at the extending | stretching process of the laminated body which concerns on this invention. The schematic diagram which shows an example of the extending | stretching direction of the laminated body in the diagonal stretch tenter shown by (A) and (B) of FIG. Schematic which shows an example (example which extends | stretches diagonally after extending | stretching from a elongate laminated body roll) of the other manufacturing method of the extending | stretching laminated body which concerns on this invention. Schematic which shows an example (example which stretches diagonally continuously, without winding up a long laminated body film reaction) other manufacturing methods of the extending | stretching laminated body which concerns on this invention.

  The method for producing a roll-shaped circularly polarizing plate of the present invention is a method for producing a roll-shaped circularly polarizing plate that produces a roll-shaped circularly polarizing plate in which at least a first protective film and a polarizer are laminated. The first protective film is produced by a step of laminating a hydrophilic polymer layer on a thermoplastic resin layer by a coating method and a step of stretching so as to have an inclination of 45 ° ± 10 ° with respect to the transport direction. The in-plane phase value Ro satisfies the condition defined by the formula (i), and the angle formed between the slow axis of the first protective film and the absorption axis of the polarizer is 45 ° ± 10 °. As described above, a roll-shaped circularly polarized light having a step of bonding the first protective film and the polarizer, and producing a circularly polarizing plate having high contrast, little image unevenness, and excellent wet heat durability A plate manufacturing method can be realized. This feature is a technical feature common to the inventions according to claims 1 to 7.

  As an embodiment of the present invention, the polarizer is stretched so as to have an inclination of 45 ° ± 10 ° with respect to the transport direction, and is orthogonal to the stretching axis, from the viewpoint of more manifesting the intended effect of the present invention. It is preferable to shrink by 10% to 40% in the direction of movement. Moreover, it is a preferable aspect that the film thickness after extending | stretching of the said polarizer exists in the range of 0.5-10 micrometers. Moreover, it is preferable that the draw ratio which extends | stretches the said polarizer so that it may have an inclination of 45 degrees +/- 10 degrees with respect to a conveyance direction is in the range of 2.0-7.0 times. Moreover, it is preferable to have the process of peeling the said thermoplastic resin layer, after bonding a said 1st protective film and the said polarizer. In addition, the first protective film includes a cellulose ester that is stretched within a range of 1.05 to 1.50 times in the width direction or the longitudinal direction and has an average acyl substitution degree of 1.5 to 2.7. Is a preferred embodiment.

  Hereinafter, the present invention, its components, and modes and modes for carrying out the present invention will be described in detail. In addition, "-" shown in this invention is used in the meaning which includes the numerical value described before and behind that as a lower limit and an upper limit.

《Roll circular polarizing plate》
The roll-shaped circularly polarizing plate according to the present invention includes at least a first protective film and a polarizer formed by laminating a hydrophilic polymer layer on a thermoplastic resin layer by a coating method.

  The polarizer according to the present invention is produced by a step of stretching so as to have an inclination of 45 ° ± 10 ° with respect to the transport direction, and the first protective film has an in-plane phase value Ro of 80 to 200. The first protective film and the first protective film and the polarizer so that the angle formed by the slow axis of the first protective film and the absorption axis of the polarizer is 45 ° ± 10 °. It is characterized by being manufactured by laminating a polarizer.

  First, the thermoplastic resin layer and the hydrophilic polymer layer constituting the obliquely extending polarizer and the first protective film will be described.

[Polarizer]
As described above, the polarizer according to the present invention is formed by laminating a hydrophilic polymer layer on a thermoplastic resin layer by a coating method and then stretching it so as to have an inclination of 45 ° ± 10 ° with respect to the transport direction. It is the extending | stretching laminated body manufactured.

[Thermoplastic resin layer]
In the present invention, a hydrophilic polymer layer is laminated on a thermoplastic resin layer and stretched to form a stretched laminate.

  The thermoplastic resin layer according to the present invention functions as a base material for forming a hydrophilic polymer layer. Moreover, the thermoplastic resin layer demonstrated below can also be applied as a 2nd protective film which can be used for comprising the circularly-polarizing plate which concerns on this invention.

(Thermoplastic resin)
The thermoplastic resin used for forming the thermoplastic resin layer according to the present invention has excellent properties such as transparency, mechanical strength, thermal stability, moisture barrier property, isotropic property, stretchability, etc. Cellulose resin such as triacetyl cellulose, polyester resin such as polyethylene terephthalate and polyethylene naphthalate, polyethersulfone resin, polysulfone resin, polycarbonate resin, polyamide resin such as nylon and aromatic polyamide, polyimide resin, polyethylene, polypropylene, ethylene / propylene Polyolefin resins such as copolymers, cyclic polyolefin resins having a cyclo or norbornene structure (norbornene resins), (meth) acrylic resins, polyarylate resins, polystyrene resins, polyvinyl alcohol resins, and mixtures thereof. Is, can be applied without particular limitations, among them, a polyethylene terephthalate, polypropylene, and be used cellulose resin.

  Although there is no restriction | limiting in particular also about the specific form of a cellulose resin, A cellulose ester, a cellulose ether, etc. are used.

  Although there is no restriction | limiting in particular as a specific structure of a cellulose ester resin, From the viewpoint of improvement in brittleness or transparency, a cellulose ester having an acyl group substitution degree that satisfies the conditions defined by the following formulas (1) to (3) Resins are preferred.

Formula (1)
2.0 ≦ A + B ≦ 3
Formula (2)
0.15 ≦ A ≦ 2.0
Formula (3)
1.0 ≦ B ≦ 2.75
In each of the above formulas, A represents the degree of substitution of the acetyl group, and B represents the total degree of substitution of the acyl group having 3 to 7 carbon atoms.

  If the total substitution degree (A + B) of the acyl group having 2 to 7 carbon atoms of the cellulose ester resin is 2.0 or more, that is, the residual degree of the hydroxyl groups at the 2, 3, 6 positions of the cellulose ester molecule is 1.0. If it is below, even if it is a case where a thermoplastic resin layer is applied as a 1st or 2nd protective film, a raise of a haze is prevented. Moreover, if the acyl group total substitution degree (A + B) is 2.0 or more and the substitution degree of the acyl group having 3 to 7 carbon atoms is 1.0 or more, the brittleness is prevented from being lowered.

  As for the acyl group substitution degree of the cellulose ester resin, the total substitution degree (A) is 2.0 to 3.0, the substitution degree (A) of the acetyl group is 0.15 to 2.0, and the carbon number is 3 If the substitution degree (B) of the acyl group of ˜7 is 1.2 to 3.0, there is no problem, but an acyl group other than those having 3 to 7 carbon atoms, that is, an acetyl group or an acyl group having 8 or more carbon atoms. It is preferable that the total degree of substitution is 1.3 or less. The total substitution degree (A + B) of the acyl group having 2 to 7 carbon atoms of the cellulose ester resin is more preferably in the range of 2.5 to 3.0.

  The acyl group may be an aliphatic acyl group or an aromatic acyl group. In the case of an aliphatic acyl group, it may be linear or branched and may further have a substituent. The number of carbon atoms of the acyl group in the present invention includes an acyl group substituent.

  When the cellulose ester resin has an aromatic acyl group as a substituent, the number of substituents X substituted on the aromatic ring is preferably 0 to 5. In this case as well, in the above-described preferred embodiment, attention should be paid so that the substitution degree of the acyl group having 3 to 7 carbon atoms including the substituent is 1.0 to 2.75. For example, since the benzoyl group has 7 carbon atoms, when it has a substituent containing carbon, the benzoyl group has 8 or more carbon atoms and is not included in the acyl group having 3 to 7 carbon atoms. Become.

  Further, when the number of substituents substituted on the aromatic ring is 2 or more, these may be the same or different from each other, and may be connected to each other to form a condensed polycyclic compound (for example, naphthalene, indene, indane, phenanthrene). Quinoline, isoquinoline, chromene, chroman, phthalazine, acridine, indole, indoline, etc.).

  The cellulose ester resin is particularly preferably at least one selected from cellulose acetate propionate, cellulose acetate butyrate, cellulose acetate benzoate, cellulose propionate, and cellulose butyrate. Among these, cellulose ester resins that are particularly preferred are cellulose acetate propionate and cellulose propionate. In the present invention, two or more kinds of cellulose ester resins can be mixed and used.

  The portion that is not substituted with an acyl group usually exists as a hydroxyl group. These can be synthesized by known methods. Moreover, the substitution degree of an acetyl group and the substitution degree of other acyl groups are determined by the method prescribed in ASTM-D817-96.

  The weight average molecular weight (Mw) of the cellulose ester resin is preferably 75,000 or more, more preferably in the range of 75,000 to 300,000, and more preferably in the range of 100,000 to 240,000, particularly from the viewpoint of improving brittleness. In particular, those within the range of 160000 to 240000 are particularly preferred. When the weight average molecular weight (Mw) of the cellulose ester resin is less than 75,000, the heat resistance and brittleness improvement effects may not be sufficiently obtained.

  Although there is no restriction | limiting in particular about the thickness of the thermoplastic resin layer which comprises an extending | stretching laminated body, It exists in the range of 5-60 micrometers in general, Preferably it exists in the range of 5-30 micrometers. If the said thickness is 5 micrometers or more, the intensity | strength as a polarizing plate is enough. On the other hand, if the said thickness is 30 micrometers or less, generation | occurrence | production of the curvature of a panel can be suppressed. In addition, as a value of the thickness of the thermoplastic resin layer, a value measured by a method of producing a film in which only a base film is stretched under the same conditions is adopted.

  The thermoplastic resin layer may be configured to contain a resin or additive other than the cellulose ester resin, as long as the function of holding the hydrophilic polymer layer or each function when applied as a protective film is not impaired. .

  As a form in which the thermoplastic resin layer contains a resin other than the cellulose ester resin, a form in which the cellulose ester resin and the acrylic resin are contained in a compatible state is exemplified. About such a form, the content currently disclosed by the international publication 2011/121720 specification and the international publication 2011/121817 specification can be referred.

  Moreover, a cellulose ether resin can be used as a thermoplastic resin. Although there is no restriction | limiting in particular also about the specific form of a cellulose ether resin, It has an ether bond in the at least 1 substituent of the 2, 3, 6 position in a cellulose molecule. The ether bond referred to here is a carbon-oxygen-carbon bond. Examples of the cellulose ether include, but are not limited to, methyl cellulose, ethyl cellulose, carboxymethyl cellulose, carboxymethyl ethyl cellulose, hydroxyethyl cellulose, hydroxyethyl methyl cellulose, hydroxypropyl methyl cellulose, and the like. Further, ethyl cellulose is optimal for ensuring transparency and durability as an optical film. The degree of ethoxyl substitution is preferably in the range of 1.9 to 2.9, and in the range of 2.2 to 2.9 from the balance between the viscosity at the time of melting and the stability of the moist heat resistant environment. Particularly preferred. The degree of ether substitution can be quantified by the method described in ASTM D4794-94. The molecular weight of the cellulose ether only needs to be able to be formed into a film alone. Specifically, the number average molecular weight Mn may be in the range of 30,000 ≦ Mn ≦ 300,000 (polystyrene conversion). Preferably, 50,000-200,000 is used. If the molecular weight is too small, the film becomes fragile, and if the molecular weight is too high, the viscosity is high and the molding stability at the time of molding processing is deteriorated, which is not preferable for production.

(Additive for thermoplastic resin layer)
Various additives can be used for the thermoplastic resin layer according to the present invention.

<Low molecular weight acrylic polymer>
Examples of the additive that can be added to the thermoplastic resin layer include a low molecular weight acrylic polymer. The weight average molecular weight (Mw) of the low molecular weight acrylic polymer is preferably in the range of 500 to 30,000. Among low molecular weight acrylic polymers, polymer X ₁ having a weight average molecular weight of 500 to 30,000 obtained by polymerizing ethylenically unsaturated monomer Xa having no aromatic ring and no hydrophilic group in the molecule, or aromatic ring in the molecule And an ethylenically unsaturated monomer Xa having no hydrophilic group and an ethylenically unsaturated monomer Xb having no hydrophilic ring in the molecule and having a hydrophilic group, having a weight average molecular weight of 500 to 30,000 preferably contains a polymer X _2. Here, examples of the ethylenically unsaturated monomer Xa having no aromatic ring and no hydrophilic group in the molecule include (meth) acrylic acid esters as described later, and methyl methacrylate (MMA) is particularly preferable. Examples of the ethylenically unsaturated monomer Xb having no hydrophilic ring in the molecule and having a hydrophilic group include acryloylmorpholine, vinyl pyrrolidone, and hydroxyethyl methacrylate. There is no particular restriction as to the content of the constitutional unit Xb derived constituent units derived from Xa in X _2, structural units derived from Xa: as the mass ratio of the constituent unit derived from Xb, 50: 50~95: 5 is preferably 60:40 to 90:10 is more preferable, and the range of 70:30 to 80:20 is particularly preferable.

  In addition, the weight average molecular weight of the acrylic polymer mentioned above becomes like this. Preferably it is 1500-20000, More preferably, it is 2000-10000, Especially preferably, it exists in the range of 2500-5000. If the weight average molecular weight of the acrylic polymer is in such a range, an advantage that a balance between volatility and compatibility is easily obtained can be obtained.

  Further, the content of the acrylic polymer in the thermoplastic resin layer described above is preferably in the range of 10 to 40% by mass, more preferably in the range of 20 to 30% by mass with respect to 100% by mass of the cellulose ester resin. It is.

  Additives other than the low molecular weight acrylic polymer can include the following plasticizers, sugar ester compounds, polyester compounds, ultraviolet absorbers, infrared absorbers, and matting agents (fine particles). Furthermore, the retardation adjusting agent which can be used as an additive of the 1st protective film mentioned later, retardation developing agent, etc. can be mentioned.

<Plasticizer>
Although there is no restriction | limiting in particular about the specific form of a plasticizer, For example, a polyester plasticizer is mentioned. There is no restriction | limiting in particular about the specific structure of a polyester plasticizer, The polyester plasticizer which has an aromatic ring or a cycloalkyl ring in a molecule | numerator can be used. As a polyester plasticizer, the polyester compound represented by following General formula (1) is mentioned, for example.

General formula (1)
X—O—B— {O—C (═O) —A—C (═O) —O—B} _n —O—X
In the general formula (1), B represents a linear or branched alkylene group or cycloalkylene group having 2 to 6 carbon atoms, and A represents an aromatic ring having 6 to 14 carbon atoms, or 2 to 6 carbon atoms. A linear or branched alkylene group or a cycloalkylene group, X represents a hydrogen atom or a monocarboxylic acid residue containing an aromatic ring having 6 to 14 carbon atoms, and n represents a natural number of 1 or more.

  The polyester compound represented by the general formula (1) is composed of a dicarboxylic acid having an aromatic ring (6 to 14 carbon atoms) or a linear or branched alkylene group or cycloalkylene group (both having 2 to 6 carbon atoms) and a carbon number. It is an alternating copolymer obtained by alternating copolymerization with 2-6 linear or branched alkylene diols or cycloalkylene diols. The aromatic dicarboxylic acid and the dicarboxylic acid having a linear or branched alkylene group or cycloalkylene group may be used alone or as a mixture, but the main component constituting the polarizing plate protective film may be used. In view of compatibility with a resin (for example, a cellulose ester resin), it is preferable that at least 10% of an aromatic dicarboxylic acid is contained. Moreover, you may seal both ends with the monocarboxylic acid which has an aromatic ring (C6-C14).

  Examples of the dicarboxylic acid having an aromatic ring (6 to 14 carbon atoms), that is, an aromatic dicarboxylic acid having 6 to 16 carbon atoms include phthalic acid, isophthalic acid, terephthalic acid, 1,5-naphthalenedicarboxylic acid, 1, 4-naphthalenedicarboxylic acid, 1,8-naphthalenedicarboxylic acid, 2,3-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 2,8-naphthalenedicarboxylic acid, 2,2'-biphenyldicarboxylic acid, 4,4 '-Biphenyldicarboxylic acid, and the like. Among these, terephthalic acid, 2,6-naphthalenedicarboxylic acid, and 4,4′-biphenyldicarboxylic acid are preferable.

  Examples of the dicarboxylic acid having a linear or branched alkylene group or cycloalkylene group (2 to 6 carbon atoms) include malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, and 1,2-cyclohexane. Examples thereof include dicarboxylic acid and 1,4-cyclohexanedicarboxylic acid. Of these, succinic acid, adipic acid, and 1,4-cyclohexanedicarboxylic acid are preferable.

  Examples of the linear or branched alkylene diol or cycloalkylene diol having 2 to 6 carbon atoms include ethanediol (ethylene glycol), 1,2-propanediol, 1,3-propanediol, 1,2- Butanediol, 1,3-butanediol, 2-methyl-1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6- Examples include hexanediol, 1,4-cyclohexanediol, and 1,4-cyclohexanedimethanol. Among these, ethanediol (ethylene glycol), 1,2-propanediol, 1,3-propanediol, and 1,3-butanediol are preferable.

  Among these, A is preferably a benzene ring, naphthalene ring or biphenyl ring which may have a substituent, from the viewpoint of excellent plasticity imparting performance. Here, the “substituent” that the benzene ring, naphthalene ring or biphenyl ring may have is an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms. is there.

  Examples of the monocarboxylic acid having an aromatic ring (having 6 to 14 carbon atoms) that seals both ends of the polyester compound include benzoic acid, orthotoluic acid, metatoluic acid, p-toluic acid, p-tert-butylbenzoic acid, and dimethylbenzoic acid. Examples include acids and paramethoxybenzoic acid. Of these, benzoic acid, p-toluic acid and p-tert-butylbenzoic acid are preferred.

  Aromatic polyester compounds can be prepared by the conventional methods, such as the above-mentioned hot-melt condensation method by the polyesterification reaction or transesterification reaction between the dicarboxylic acid and alkylene diol or cycloalkylene diol, or the interfacial condensation method between acid chlorides of these acids and glycols. It can be easily synthesized by either method. Furthermore, by adding the above-described aromatic monocarboxylic acid, a polyester compound in which both ends are sealed can be synthesized.

  The thermoplastic resin layer can further contain a plasticizer other than the polyester compound represented by the general formula (1).

  Although it does not specifically limit as plasticizers other than the polyester compound represented by General formula (1), Preferably, polyhydric carboxylic acid ester plasticizer, glycolate plasticizer, phthalate ester plasticizer, fatty acid ester type It is selected from plasticizers and polyhydric alcohol ester plasticizers, ester plasticizers, acrylic plasticizers and the like.

  Of these, when two or more plasticizers are used, at least one plasticizer is preferably a polyhydric alcohol ester plasticizer.

  The polyhydric alcohol ester plasticizer is a plasticizer comprising an ester of a dihydric or higher aliphatic polyhydric alcohol and a monocarboxylic acid, and preferably has an aromatic ring or a cycloalkyl ring in the molecule. Preferably it is a 2-20 valent aliphatic polyhydric alcohol ester.

  The polyhydric alcohol preferably used in the present invention is represented by the following general formula (a).

Formula (a)
R ₁₁ - _{(OH) n}
In the general formula (a), R ₁₁ represents an n-valent organic group, n represents a positive integer of 2 or more, and the OH group represents an alcoholic or phenolic hydroxy group (hydroxyl group).

  Examples of preferred polyhydric alcohols include the following, but are not limited thereto.

  Adonitol, arabitol, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propanediol, 1,3-propanediol, dipropylene glycol, tripropylene glycol, 1,2-butanediol, 1,3- Butanediol, 1,4-butanediol, dibutylene glycol, 1,2,4-butanetriol, 1,5-pentanediol, 1,6-hexanediol, hexanetriol, galactitol, mannitol, 3-methylpentane- Examples include 1,3,5-triol, pinacol, sorbitol, trimethylolpropane, trimethylolethane, xylitol and the like.

  In particular, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, sorbitol, trimethylolpropane, and xylitol are preferable.

  There is no restriction | limiting in particular as monocarboxylic acid used for polyhydric alcohol ester, Well-known aliphatic monocarboxylic acid, alicyclic monocarboxylic acid, aromatic monocarboxylic acid, etc. can be used. Use of an alicyclic monocarboxylic acid or aromatic monocarboxylic acid is preferred in terms of improving moisture permeability and retention.

  Examples of preferred monocarboxylic acids include the following, but are not limited thereto.

  As the aliphatic monocarboxylic acid, a fatty acid having a straight chain or side chain having 1 to 32 carbon atoms can be preferably used. The number of carbon atoms is more preferably 1-20, and particularly preferably 1-10. The inclusion of acetic acid is preferred because the compatibility with cellulose acetate increases, and it is also preferred to use a mixture of acetic acid and other monocarboxylic acids.

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

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

  Examples of preferred aromatic monocarboxylic acids include those in which 1 to 3 alkoxy groups such as an alkyl group, a methoxy group or an ethoxy group are introduced into the benzene ring of benzoic acid such as benzoic acid or toluic acid, biphenylcarboxylic acid, Examples thereof include aromatic monocarboxylic acids having two or more benzene rings such as naphthalenecarboxylic acid and tetralincarboxylic acid, or derivatives thereof. Benzoic acid is particularly preferable.

  The molecular weight of the polyhydric alcohol ester is not particularly limited, but is preferably in the range of 300 to 1500, and more preferably in the range of 350 to 750. A higher molecular weight is preferred because it is less likely to volatilize, and a smaller one is preferred in terms of moisture permeability and compatibility with cellulose acetate.

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

  The glycolate plasticizer is not particularly limited, but alkylphthalylalkyl glycolates can be preferably used.

  Examples of alkyl phthalyl alkyl glycolates include methyl phthalyl methyl glycolate, ethyl phthalyl ethyl glycolate, propyl phthalyl propyl glycolate, butyl phthalyl butyl glycolate, octyl phthalyl octyl glycolate, methyl phthalyl ethyl Glycolate, ethyl phthalyl methyl glycolate, ethyl phthalyl propyl glycolate, methyl phthalyl butyl glycolate, ethyl phthalyl butyl glycolate, butyl phthalyl methyl glycolate, butyl phthalyl ethyl glycolate, propyl phthalyl butyl glycol Butyl phthalyl propyl glycolate, methyl phthalyl octyl glycolate, ethyl phthalyl octyl glycolate, octyl phthalyl methyl glycolate, octyl phthalate Ethyl glycolate, and the like.

  Examples of the phthalate ester plasticizer include diethyl phthalate, dimethoxyethyl phthalate, dimethyl phthalate, dioctyl phthalate, dibutyl phthalate, di-2-ethylhexyl phthalate, dioctyl phthalate, dicyclohexyl phthalate, and dicyclohexyl terephthalate.

  Examples of the citrate plasticizer include acetyl trimethyl citrate, acetyl triethyl citrate, and acetyl tributyl citrate.

  Examples of fatty acid ester plasticizers include butyl oleate, methylacetyl ricinoleate, and dibutyl sebacate.

  Examples of the phosphate ester plasticizer include triphenyl phosphate, tricresyl phosphate, cresyl diphenyl phosphate, octyl diphenyl phosphate, diphenyl biphenyl phosphate, trioctyl phosphate, tributyl phosphate and the like.

  The polyvalent carboxylic acid ester compound is composed of an ester of a polyvalent carboxylic acid and an alcohol having a valence of 2 or more, preferably in the range of 20 to 20. The aliphatic polyvalent carboxylic acid is preferably 2 to 20 valent, and in the case of an aromatic polyvalent carboxylic acid or an alicyclic polyvalent carboxylic acid, it is preferably within a range of 3 to 20 valent.

  The polyvalent carboxylic acid is represented by the following general formula (b).

General formula (b)
R ₁₂ (COOH) _m1 (OH) _n1
In the general formula (b), R ₁₂ is an (m1 + n1) -valent organic group, m1 is a positive integer of 2 or more, n1 is an integer of 0 or more, a COOH group is a carboxy group, an OH group is alcoholic or phenolic hydroxy Represents a group.

  Examples of preferred polyvalent carboxylic acids include, but are not limited to, the following.

  Trivalent or higher aromatic polyvalent carboxylic acids such as trimellitic acid, trimesic acid, pyromellitic acid or derivatives thereof, succinic acid, adipic acid, azelaic acid, sebacic acid, oxalic acid, fumaric acid, maleic acid, tetrahydrophthal An aliphatic polyvalent carboxylic acid such as an acid, an oxypolyvalent carboxylic acid such as tartaric acid, tartronic acid, malic acid and citric acid can be preferably used. In particular, it is preferable to use an oxypolycarboxylic acid from the viewpoint of improving retention.

  There is no restriction | limiting in particular as alcohol used for the polyhydric carboxylic acid ester compound which can be used for this invention, Well-known alcohol and phenols can be used.

  For example, an aliphatic saturated alcohol or aliphatic unsaturated alcohol having a straight chain or a side chain having 1 to 32 carbon atoms can be preferably used. It is more preferable that it is C1-C20, and it is especially preferable that it is C1-C10.

  In addition, alicyclic alcohols such as cyclopentanol and cyclohexanol or derivatives thereof, aromatic alcohols such as benzyl alcohol and cinnamyl alcohol, or derivatives thereof can also be preferably used.

  When an oxypolycarboxylic acid is used as the polycarboxylic acid, the alcoholic or phenolic hydroxy group (hydroxyl group) of the oxypolycarboxylic acid may be esterified with a monocarboxylic acid. Examples of preferred monocarboxylic acids include the following, but the present invention is not limited thereto.

  As the aliphatic monocarboxylic acid, a fatty acid having a straight chain or a side chain having 1 to 32 carbon atoms can be preferably used. It is more preferable that it is C1-C20, and it is especially preferable that it is C1-C10.

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

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

  Examples of preferred aromatic monocarboxylic acids include those in which an alkyl group is introduced into the benzene ring of benzoic acid such as benzoic acid and toluic acid, and two or more benzene rings such as biphenyl carboxylic acid, naphthalene carboxylic acid, and tetralin carboxylic acid. The aromatic monocarboxylic acid which has, or those derivatives can be mentioned. Particularly preferred are acetic acid, propionic acid, and benzoic acid.

  The molecular weight of the polyvalent carboxylic acid ester compound is not particularly limited, but is preferably in the range of 300 to 1000, and more preferably in the range of 350 to 750. The larger one is preferable in terms of improvement in retention, and the smaller one is preferable in terms of moisture permeability and compatibility with cellulose acetate.

  The alcohol used for the polyvalent carboxylic acid ester that can be used in the present invention may be one kind or a mixture of two or more kinds.

  The acid value of the polyvalent carboxylic acid ester compound that can be used in the present invention is preferably 1 mgKOH / g or less, and more preferably 0.2 mgKOH / g or less. Setting the acid value in the above range is preferable because the environmental fluctuation of the retardation is also suppressed.

  In addition, an acid value means the milligram number of potassium hydroxide required in order to neutralize the acid (carboxy group which exists in a sample) contained in 1g of samples. The acid value is measured according to JIS K0070.

  Examples of particularly preferred polyvalent carboxylic acid ester compounds are shown below, but the present invention is not limited thereto.

  For example, triethyl citrate, tributyl citrate, acetyl triethyl citrate (ATEC), acetyl tributyl citrate (ATBC), benzoyl tributyl citrate, acetyl triphenyl citrate, acetyl tribenzyl citrate, dibutyl tartrate, diacetyl dibutyl tartrate, Examples include tributyl trimellitic acid and tetrabutyl pyromellitic acid.

  The plasticizer is preferably contained within a range of 0.1 to 30% by mass, more preferably within a range of 2 to 20% by mass with respect to 100% by mass of the total amount of the thermoplastic resin layer.

<Sugar ester compound>
Since the thermoplastic resin layer further includes a sugar ester compound other than the cellulose ester, hydrolysis of the cellulose ester resin is prevented, so that the water resistance of the film can be improved.

  An example of the sugar ester compound is a compound represented by the following general formula (2).

General formula (2)
(HO) _m -Q- (OC (= O) -R) _p
In the general formula (2), Q represents a monosaccharide or disaccharide residue, R represents an aliphatic group or an aromatic group, and m is directly bonded to the monosaccharide or disaccharide residue. P is the sum of the number of — (O—C (═O) —R) groups directly attached to the monosaccharide or disaccharide residue, 3 ≦ m + p ≦ 8 and p ≠ 0.

  The compound having the structure represented by the general formula (2) is a single kind of compound in which the number (m) of hydroxyl groups and the number (p) of — (O—C (═O) —R) groups are fixed. It is difficult to isolate, and it is known that a compound in which several components having different m and p in the formula are mixed is obtained. Therefore, the performance as a mixture in which the number (m) of hydroxyl groups and the number (p) of — (O—C (═O) —R) groups are important is important, and the cellulose acylate film as in this embodiment A compound having a structure represented by the general formula (2) with respect to haze characteristics and a mixing ratio of a component of m = 0 and a component of m> 0 is 45:55 to 0: 100. preferable. More preferably, in terms of performance and cost, the mixing ratio of the component m = 0 and the component m> 0 is in the range of 10:90 to 0.1: 99.9. In addition, the component of said m = 0 and the component of m> 0 can be measured by a high performance liquid chromatography by a conventional method.

  In the general formula (2), Q represents a monosaccharide or disaccharide residue. Specific examples of monosaccharides include allose, altrose, glucose, mannose, gulose, idose, galactose, talose, ribose, arabinose, xylose, lyxose, and the like.

  Specific examples of the disaccharide include trehalose, sucrose, maltose, cellobiose, gentiobiose, lactose, and isotrehalose.

  In the general formula (2), R represents an aliphatic group or an aromatic group. Here, the aliphatic group and the aromatic group may each independently have a substituent.

  In the general formula (2), m is the total number of hydroxyl groups directly bonded to the monosaccharide or disaccharide residue, and p is directly bonded to the monosaccharide or disaccharide residue. The total number of — (O—C (═O) —R) groups. In addition, it is necessary that 3 ≦ m + p ≦ 8, and it is preferable that 4 ≦ m + p ≦ 8. Further, p ≠ 0. In addition, when p is 2 or more, the — (O—C (═O) —R) groups may be the same or different.

  The aliphatic group in the definition of R may be linear, branched or cyclic, preferably has 1 to 25 carbon atoms, more preferably has 1 to 20 carbon atoms, 15 is particularly preferred. Specific examples of the aliphatic group include, for example, methyl, ethyl, n-propyl, iso-propyl, cyclopropyl, n-butyl, iso-butyl, tert-butyl, amyl, iso-amyl, tert-amyl, n- Examples include hexyl, cyclohexyl, n-heptyl, n-octyl, bicyclooctyl, adamantyl, n-decyl, tert-octyl, dodecyl, hexadecyl, octadecyl, didecyl and the like.

  The aromatic group in the definition of R may be an aromatic hydrocarbon group or an aromatic heterocyclic group, and more preferably an aromatic hydrocarbon group. The aromatic hydrocarbon group preferably has 6 to 24 carbon atoms, and more preferably 6 to 12 carbon atoms. Specific examples of the aromatic hydrocarbon group include benzene, naphthalene, anthracene, biphenyl, terphenyl and the like. As the aromatic hydrocarbon group, benzene, naphthalene, and biphenyl are particularly preferable. As the aromatic heterocyclic group, those containing at least one of an oxygen atom, a nitrogen atom or a sulfur atom are preferable. Specific examples of the heterocyclic ring include, for example, furan, pyrrole, thiophene, imidazole, pyrazole, pyridine, pyrazine, pyridazine, triazole, triazine, indole, indazole, purine, thiazoline, thiadiazole, oxazoline, oxazole, oxadiazole, quinoline, Examples include isoquinoline, phthalazine, naphthyridine, quinoxaline, quinazoline, cinnoline, pteridine, acridine, phenanthroline, phenazine, tetrazole, benzimidazole, benzoxazole, benzthiazole, benzotriazole, and tetrazaindene. As the aromatic heterocyclic group, pyridine, triazine, and quinoline are particularly preferable.

  It is preferable that a sugar ester compound is contained in the range of 0.1-30 mass% with respect to the total mass of a thermoplastic resin layer, More preferably, it exists in the range of 2-20 mass%.

<polyester>
The thermoplastic resin layer also preferably contains a polyester represented by the following general formula (c) or (d).

Formula (c)
B _1- (G ₁ -A _1- ) _m G ₁ -B ₁
In the above general formula (c), B ₁ represents a monocarboxylic acid, G ₁ represents a divalent alcohol, and A ₁ represents a dibasic acid. B ₁ , G ₁ and A ₁ do not contain an aromatic ring. m represents the number of repetitions.

General formula (d)
B _2- (A ₂ -G _2- ) _n A ₂ -B ₂
In the general formula (d), B ₂ represents a monoalcohol, G ₂ represents a divalent alcohol, and A 2 represents a dibasic acid. B ₂ , G ₂ , and A ₂ do not contain an aromatic ring. n represents the number of repetitions.

The monocarboxylic acids represented by B _1, is not particularly limited and includes known aliphatic monocarboxylic acids, can be used alicyclic monocarboxylic acid.

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

  As the aliphatic monocarboxylic acid, a straight-chain or side-chain fatty acid having 1 to 32 carbon atoms can be preferably used. The number of carbon atoms is more preferably 1-20, and particularly preferably 1-12. When acetic acid is contained, the compatibility with cellulose acylate is increased, and it is also preferable to use a mixture of acetic acid and another monocarboxylic acid.

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

The monoalcohol component represented by B ₂ is not particularly limited, and known alcohols can be used. For example, an aliphatic saturated alcohol or aliphatic unsaturated alcohol having a straight chain or a side chain having 1 to 32 carbon atoms can be preferably used. The number of carbon atoms is more preferably 1-20, and particularly preferably 1-12.

Examples of the divalent alcohol component represented by G ₁ and G ₂ include the following, but the present invention is not limited thereto. For example, ethylene glycol, diethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,2-butylene glycol, 1,3-butylene glycol, 1,4-butylene glycol, 1,5-pentanediol, , 6-hexanediol, 1,5-pentylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, etc., among which ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1 , 2-butylene glycol, 1,3-butylene glycol, 1,4-butylene glycol, 1,6-hexanediol, diethylene glycol and triethylene glycol are preferred, and 1,3-propylene glycol, 1,4 Butylene glycol 1,6-hexanediol, diethylene glycol is preferably used.

The dibasic acid (dicarboxylic acid) component represented by A ₁ or A ₂ is preferably an aliphatic dibasic acid or an alicyclic dibasic acid. Examples of the aliphatic dibasic acid include malonic acid and succinic acid. , Glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedicarboxylic acid, dodecanedicarboxylic acid, etc., especially aliphatic dicarboxylic acids having 4 to 12 carbon atoms, at least one selected from these One can be used. That is, two or more dibasic acids may be used in combination.

  m and n represent the number of repetitions and are preferably in the range of 1 or more and 170 or less.

  Moreover, the thermoplastic resin layer can contain polyester represented by the following general formula (e) or (f).

General formula (e)
B _3- (G ₃ -A _3- ) _m1 G ₃ -B ₃
In the general formula (e), B ₃ represents a monocarboxylic acid having 1 to 12 carbon atoms, G ₃ represents a divalent alcohol having 2 to 12 carbon atoms, and A ₃ is a 2 base having 2 to 12 carbon atoms. Represents an acid. B ₃ , G ₃ and A ₃ do not contain an aromatic ring. m1 represents the number of repetitions.

Formula (f)
_{B 4 - (A 4 -G 4} -) n1 A 4 -B 4
In the general formula (f), B ₄ represents a monoalcohol having 1 to 12 carbon atoms, G ₄ represents a divalent alcohol having 2 to 12 carbon atoms, and A ₄ represents a dibasic acid having 2 to 12 carbon atoms. Represents. B ₄ , G ₄ , and A ₄ do not contain an aromatic ring. n1 represents the number of repetitions.

In the general formulas (e) and (f), B ₃ and B ₄ have the same meanings as B ₁ and B ₂ in the general formula (c) or (d). G ₃ , G ₄ , A ₃ , and A ⁴ are each an alcohol component having 2 to 12 carbon atoms in G ₁ , G ₂ , A ₁ , or A ₂ in the general formula (c) or (d) or Corresponds to the dibasic acid component.

  The number average molecular weight of the polyester is preferably in the range of 1000 or more and 10,000 or less. If the number average molecular weight is less than 1000, breakage tends to occur at high temperature and high magnification stretching, and if it exceeds 10,000, whitening due to phase separation tends to increase.

  The polyester is preferably contained within a range of 0.1 to 30% by mass, and more preferably within a range of 2 to 20% by mass with respect to the total mass of the thermoplastic resin layer.

<Ultraviolet absorber>
The thermoplastic resin layer can also contain an ultraviolet absorber. The ultraviolet absorber is intended to improve durability by absorbing ultraviolet light having a wavelength of 400 nm or less. In particular, the transmittance at a wavelength of 370 nm is preferably 10% or less, more preferably 5% or less, Preferably it is 2% or less. In addition, when a thermoplastic resin layer contains a ultraviolet absorber, it is preferable that the said ultraviolet absorber is contained 2 or more types.

  Although the ultraviolet absorber used in the present invention is not particularly limited, for example, oxybenzophenone compounds, benzotriazole compounds, salicylic acid ester compounds, benzophenone compounds, cyanoacrylate compounds, triazine compounds, nickel complex compounds, inorganic Examples thereof include powders.

  For example, 5-chloro-2- (3,5-di-sec-butyl-2-hydroxylphenyl) -2H-benzotriazole, (2-2H-benzotriazol-2-yl) -6- (linear and side Chain dodecyl) -4-methylphenol, 2-hydroxy-4-benzyloxybenzophenone, 2,4-benzyloxybenzophenone, etc., and tinuvin 109, tinuvin 171, tinuvin 234, tinuvin 326, tinuvin 327, tinuvin 328, etc. These are commercially available products made by BASF Japan Ltd. and can be preferably used.

  The UV absorbers preferably used in the present invention are benzotriazole UV absorbers, benzophenone UV absorbers, and triazine UV absorbers, particularly preferably benzotriazole UV absorbers and benzophenone UV absorbers. . In addition, a discotic compound such as a compound having a 1,3,5 triazine ring is also preferably used as the ultraviolet absorber. As the UV absorber, a polymer UV absorber can also be preferably used, and in particular, a polymer type UV absorber described in JP-A-6-148430 is preferably used.

  The method of adding the UV absorber can be added to the dope after dissolving the UV absorber in an alcohol such as methanol, ethanol or butanol, an organic solvent such as methylene chloride, methyl acetate, acetone or dioxolane or a mixed solvent thereof. Or you may add directly in dope composition. Moreover, what does not melt | dissolve in an organic solvent like inorganic powder should just add to dope after disperse | distributing in an organic solvent and a cellulose-ester resin using a dissolver or a sand mill.

  The ultraviolet absorber is preferably contained within a range of 0.1 to 15% by mass, and more preferably within a range of 1 to 10% by mass with respect to 100% by mass of the total amount of the thermoplastic resin layer. .

<Infrared absorber>
The thermoplastic resin layer may include an infrared absorber. By containing an infrared absorber, the reverse wavelength dispersibility of the thermoplastic resin layer can be adjusted.

  The infrared absorber preferably has a maximum absorption in a wavelength region of 750 to 1100 nm, and more preferably has a maximum absorption in a wavelength region of 800 to 1000 nm. Moreover, it is preferable that the infrared absorber has substantially no absorption in the visible region.

  As the infrared absorbing agent, it is preferable to use an infrared absorbing dye or an infrared absorbing pigment, and it is particularly preferable to use an infrared absorbing dye.

  The infrared absorbing dye includes an organic compound and an inorganic compound. It is preferable to use an infrared absorbing dye that is an organic compound. Organic infrared absorbing dyes include cyanine compounds, metal chelate compounds, aminium compounds, diimonium compounds, quinone compounds, squarylium compounds, and methine compounds. Infrared absorbing dyes are described in Coloring Materials, 61 [4] 215-226 (1988), and Chemical Industry, 43-53 (1986, May).

  The infrared absorber is preferably included within a range of 0.1 to 30% by mass, and more preferably within a range of 2 to 20% by mass with respect to 100% by mass of the total amount of the thermoplastic resin layer. .

<Matting agent (fine particles)>
In order to improve the handleability, the thermoplastic resin layer may have, for example, silicon dioxide, titanium dioxide, aluminum oxide, zirconium oxide, calcium carbonate, kaolin, talc, calcined calcium silicate, hydrated calcium silicate, aluminum silicate, silica It is preferable to contain inorganic fine particles such as magnesium oxide and calcium phosphate and fine particles such as a crosslinked polymer as a matting agent. Of these, silicon dioxide is preferable because it can reduce the haze of the film.

  The average primary particle diameter of the fine particles is preferably 20 nm or less, more preferably 5 to 16 nm, and particularly preferably in the range of 5 to 12 nm.

  These fine particles preferably form secondary particles having a particle size of 0.1 to 5 μm and are contained in the film, and the preferable average particle size is 0.1 to 2 μm, more preferably 0.2 to 0. .6 μm. Thereby, the unevenness | corrugation about 0.1-1.0 micrometer high can be formed in the film surface, and this can give appropriate slipperiness to the film surface.

  The average primary particle diameter of the fine particles used in the present invention is measured by observing the particles with a transmission electron microscope (magnification of 500,000 to 2,000,000 times), observing 100 particles, measuring the particle diameter, and measuring the average value. Is the average primary particle size.

  The apparent specific gravity of the fine particles is preferably 70 g / liter or more, more preferably 90 to 200 g / liter, and particularly preferably in the range of 100 to 200 g / liter. A higher apparent specific gravity is preferable because a high-concentration dispersion can be produced and haze and aggregates are improved, and it is particularly preferably used when preparing a dope having a high solid content concentration.

  For example, silicon dioxide fine particles having an average primary particle diameter of 20 nm or less and an apparent specific gravity of 70 g / liter or more are obtained by burning vaporized silicon tetrachloride and hydrogen in air at 1000 to 1200 ° C. Can be obtained at For example, Aerosil R812, Aerosil 200V, Aerosil R972V (above, manufactured by Nippon Aerosil Co., Ltd.) are commercially available and can be used.

  The matting agent (fine particles) is preferably contained within a range of 0.01 to 5% by mass, and preferably within a range of 0.1 to 3% by mass with respect to the total mass of the thermoplastic resin layer. More preferred.

<Colorant>
The thermoplastic resin layer may contain a colorant. The “colorant” means a dye or a pigment. In the present invention, those having an effect of making the color tone of the liquid crystal screen blue, adjusting the yellow index, and reducing haze are particularly preferable. Various dyes and pigments can be used as the colorant, and anthraquinone dyes, azo dyes, phthalocyanine pigments and the like are particularly effective.

  The colorant is preferably contained within a range of 0.01 to 5% by mass, and more preferably within a range of 0.1 to 3% by mass with respect to the total mass of the thermoplastic resin layer.

[Hydrophilic polymer layer]
The stretched laminate according to the present invention includes a hydrophilic polymer layer on a thermoplastic resin layer. The hydrophilic polymer layer is a layer containing a hydrophilic polymer as a main component. And in the circularly-polarizing plate which concerns on this invention, it is preferable that a hydrophilic polymer layer adsorb | sucks a dichroic substance. Thereby, the hydrophilic polymer layer functions as a polarizer in the circularly polarizing plate according to the present invention.

  Although there is no restriction | limiting in particular about the hydrophilic polymer which comprises a hydrophilic polymer layer, A polyvinyl alcohol-type material is illustrated preferably. Examples of the polyvinyl alcohol-based material include polyvinyl alcohol and derivatives thereof. Examples of polyvinyl alcohol derivatives include polyvinyl formal, polyvinyl acetal, etc., olefins such as ethylene and propylene, unsaturated carboxylic acids such as acrylic acid, methacrylic acid, and crotonic acid, alkyl esters thereof, acrylamide, and the like. Can be mentioned. The degree of polymerization of polyvinyl alcohol is preferably about 100 to 10,000, and more preferably 1,000 to 10,000. A saponification degree of about 80 to 100 mol% is generally used. In addition to the above, examples of the hydrophilic polymer include partially saponified ethylene / vinyl acetate copolymer, dehydrated polyvinyl alcohol and dehydrochlorinated polyvinyl chloride. As the hydrophilic polymer, it is preferable to use polyvinyl alcohol among polyvinyl alcohol materials.

  The hydrophilic polymer layer may contain additives such as a plasticizer and a surfactant in addition to the above-described hydrophilic polymer. Examples of the plasticizer include polyols and condensates thereof, and examples include glycerin, diglycerin, triglycerin, ethylene glycol, propylene glycol, and polyethylene glycol. The amount of the plasticizer used is not particularly limited, but it is preferably 20% by mass or less with respect to 100% by mass of the total amount of the hydrophilic polymer layer.

  Next, a dyeing process is performed on the hydrophilic polymer layer.

  The dyeing process is performed by adsorbing the dichroic substance to the hydrophilic polymer layer of the laminate. Since the dichroic substance is as described above, the description is omitted here. The dyeing process is performed, for example, by immersing the laminate in a solution (dyeing solution) containing a dichroic substance. As the staining solution, a solution in which a dichroic substance is dissolved in a solvent can be used. As the solvent, water is generally used, but an organic solvent compatible with water may be further added.

  Although there is no restriction | limiting in particular also about the specific structure of the dichroic substance adsorb | sucked to a hydrophilic polymer layer, For example, an iodine, an organic dye, etc. are mentioned. Organic dyes include, for example, Red BR, Red LR, Red R, Pink LB, Rubin BL, Bordeaux GS, Sky Blue LG, Lemon Yellow, Blue BR, Blue 2R, Navy RY, Green LG, Violet LB, Violet B, Black H, Black B, Black GSP, Yellow 3G, Yellow R, Orange LR, Orange 3R, Scarlet GL, Scarlet KGL, Congo Red, Brilliant Violet BK, Spura Blue G, Spura Blue GL, Spura Orange GL, Direct Sky Blue, Direct First orange S, first black, etc. can be used. Among these, from the viewpoints of water solubility and process suitability, it is preferable to add iodide, since using iodine as a dichroic material can further improve the dyeing efficiency. Examples of the iodide include potassium iodide, lithium iodide, sodium iodide, zinc iodide, aluminum iodide, lead iodide, copper iodide, barium iodide, calcium iodide, tin iodide, and iodide. Examples include titanium. The addition ratio of these iodides is preferably 0.01 to 10% by mass and more preferably 0.1 to 5% by mass in the dyeing solution. Among them, it is preferable to add potassium iodide, and the ratio (mass ratio) of iodine and potassium iodide is preferably in the range of 1: 5 to 1: 100, and in the range of 1: 6 to 1:80. More preferably, it is in the range of 1: 7 to 1:70.

  The immersion time of the laminate in the dyeing solution is not particularly limited, but usually it is preferably in the range of 15 seconds to 5 minutes, more preferably 1 minute to 3 minutes. Moreover, it is preferable that it is in the range of 10-60 degreeC, and, as for the temperature of a dyeing | staining solution, it is more preferable that it exists in the range of 20-40 degreeC. In the dyeing treatment, the dichroic substance is oriented by adsorbing the dichroic substance to the hydrophilic polymer layer of the laminate. The dyeing process can be performed before, simultaneously with, or after the stretching process of the laminate. From the viewpoint of satisfactorily orienting the dichroic material adsorbed on the hydrophilic polymer layer, the dyeing process is performed on the laminate. It is preferable to carry out after the treatment.

[Polarizer Production Method]
Next, as a method for producing a polarizer according to the present invention, a hydrophilic polymer layer is laminated on a thermoplastic resin layer by a coating method, and then has an inclination of 45 ° ± 10 ° with respect to the transport direction in the stretching process. A stretched laminate having a polarizer is formed through a stretching process. Furthermore, when manufacturing a polarizer, it is preferable from the viewpoint that the degree of polarization can be set high by shrinking within a range of 10 to 40% in a direction perpendicular to the stretching axis.

  There is no restriction | limiting in particular about the manufacturing method of the extending | stretching laminated body which concerns on this invention, It can manufacture suitably, referring the description of the column of the conventionally well-known knowledge and the Example mentioned later.

  An example of a method for producing a stretched laminate can be obtained, for example, by applying an aqueous solution containing a hydrophilic polymer to a thermoplastic resin layer, followed by drying and stretching. As a method for forming the stretched laminate, the thermoplastic resin layer and the hydrophilic polymer layer are laminated directly or via a photocurable adhesive layer, so that the thermoplastic resin layer and the hydrophilic polymer layer are integrated. Thus, a laminated body in a state of being converted is obtained.

  The thermoplastic resin layer used for producing the stretched laminate may be subjected to a stretching treatment in advance before applying an aqueous solution containing a hydrophilic polymer. As the stretching treatment, uniaxial stretching, biaxial stretching, oblique stretching, or the like is performed. Uniaxial stretching may be either longitudinal stretching performed in the longitudinal direction of the thermoplastic resin layer or transverse stretching performed in the width direction of the thermoplastic resin layer. In transverse stretching, the film can be contracted in the longitudinal direction while stretching in the width direction. Examples of the transverse stretching method include a fixed end uniaxial stretching method in which one end is fixed via a tenter, and a free end uniaxial stretching method in which one end is not fixed. Examples of the longitudinal stretching method include an inter-roller stretching method, a compression stretching method, and a stretching method using a tenter. The stretching process can be performed in multiple stages. In addition, when the extending | stretching process with respect to a base material layer is uniaxial stretching, it is preferable that it is longitudinal stretching (stretching to MD direction).

  Moreover, there is no restriction | limiting in particular about the temperature at the time of the extending | stretching process of a thermoplastic resin layer, Preferably it is 130-200 degreeC, More preferably, it exists in the range of 150-180 degreeC. The stretching treatment of the thermoplastic resin layer may be performed so that the total stretching ratio in all directions is 1.1 to 10 times the original length of the thermoplastic resin layer. Preferably it is 2-6 times, More preferably, it exists in the range of 3-5 times.

  An aqueous solution containing a hydrophilic polymer (a coating solution for forming a hydrophilic polymer) is prepared by appropriately heating a powder of a hydrophilic polymer (for example, polyvinyl alcohol) or a pulverized product or a cut product of a hydrophilic polymer film. It can be prepared by dissolving in water (hot water). Examples of the method for applying the aqueous solution containing the hydrophilic polymer onto the thermoplastic resin layer include, for example, a wire bar coating method, a roller coating method such as reverse coating and gravure coating, a spin coating method, a screen coating method, and a fountain coating. A method, a dipping method, a spray method and the like can be appropriately selected and applied.

  Drying is carried out after applying a coating solution for forming a hydrophilic polymer onto the thermoplastic resin layer. The drying temperature is usually in the range of 50 to 200 ° C, preferably in the range of 80 to 150 ° C. The drying time is usually about 5 to 30 minutes.

  In addition, as another lamination method of the stretched laminate according to the present invention, a laminate is prepared by supplying from a die or the like by a co-extrusion method of a thermoplastic resin layer forming material and a hydrophilic polymer layer forming material. It can be formed in a process. At the time of coextrusion, the material for forming the thermoplastic resin layer and the material for forming the hydrophilic polymer layer are respectively charged into the coextrusion machine so that the thicknesses of the thermoplastic resin layer and the hydrophilic polymer layer are within a desired range. It is preferable to control the coextrusion amount.

  Subsequently, the laminate obtained above is subjected to stretching treatment and dyeing treatment with a dichroic substance. The stretched laminate subjected to each treatment is subjected to stretching treatment of the hydrophilic polymer layer and dyeing treatment with the dichroic substance, so that the dichroic substance is adsorbed to the hydrophilic polymer layer and becomes a polarizer. Become functional.

  In the present invention, the hydrophilic polymer layer is laminated on the thermoplastic resin layer by the above method, dried, and then heated in the stretching process, and has an inclination of 45 ° ± 10 ° with respect to the transport direction. The film is stretched in such a manner that it is simultaneously contracted within a range of 10 to 40% in a direction orthogonal to the stretching axis, thereby forming a diagonally stretched polarizer.

  Hereinafter, a method for obliquely stretching the laminate so as to have an inclination of 45 ° ± 10 ° with respect to the transport direction will be described.

  In the manufacturing process of a laminate that is obliquely stretched according to the present invention, an obliquely stretched tenter is used to impart oblique stretching to a laminate in which a hydrophilic polymer layer is laminated on a thermoplastic resin layer. Is preferred. The diagonally stretched tenter can freely set the orientation angle of the laminate by changing the rail pattern in various ways, and can evenly orient the orientation axis of the laminate across the film width direction evenly with high precision. A film stretching apparatus capable of controlling the film thickness and retardation with high accuracy is preferable.

  FIG. 1 is a schematic view of a tenter that can be stretched obliquely and can be applied in the step of stretching a laminate according to the present invention. However, this is an example, and the present invention is not limited to this.

  In the tenter structure 1 shown in FIG. 1A that can be obliquely stretched, a laminate 4 in which a hydrophilic polymer layer is formed on a thermoplastic resin layer whose direction is controlled by a guide roller 12-1 on the tenter entrance side is as follows. The outer film holding start point 8-1 and the inner film holding start point 8-2 are supported by a gripper (also referred to as a clip gripping portion) at the position of the inner film holding start point 8-2. −1, transported and stretched in an oblique direction indicated by the locus 7-2 of the inner film holding means, and the gripping is released by the outer film holding end point 9-1 and the inner film holding end point 9-2. Conveyance is controlled by the guide roller 12-2 on the exit side, and a stretched laminate (polarizer) 5 that is obliquely stretched to have an inclination of 45 ° ± 10 ° with respect to the transport direction is formed. In the drawing, the laminated body is obliquely stretched at an angle of 45 ° ± 10 ° at an angle (feeding angle θi) of the film stretching direction 14-2 with respect to the film transport direction 14-1. At this time, in the present invention, it is preferable that the film is stretched so as to have an inclination of 45 ° ± 10 ° with respect to the transport direction and is contracted within a range of 10 to 40% in a direction perpendicular to the stretching axis. One.

  1B shows another tenter structure 2 that can be obliquely stretched, and the laminate is stretched in the same manner as the tenter structure 1 that can be obliquely stretched shown in FIG. 1A. Can do.

  Stretching in the stretching step of the laminate in which the hydrophilic polymer layer is formed on the thermoplastic resin layer according to the present invention is performed using the tenter capable of oblique stretching. This tenter is an apparatus that widens a long film original fabric in an oblique direction with respect to its traveling direction (moving direction of the middle point in the film width direction) in an environment heated by an oven. The tenter includes an oven, a pair of rails on the left and right on which a gripping tool for transporting the film travels, and a number of gripping tools that travel on the rails. The both ends of the laminate fed out from the film roll and sequentially supplied to the inlet of the tenter are gripped by the gripping tool, the previously prepared laminate is guided into the oven, and stretched from the gripping tool at the outlet of the tenter. Release the laminate. The stretched laminate released from the gripping tool is wound around the core. Each of the pair of rails has an endless continuous track, and the gripping tool that has opened the stack at the outlet of the tenter travels outside and is sequentially returned to the inlet.

  As shown in FIGS. 1A and 1B, the tenter rail shape is asymmetrical on the left and right depending on the orientation angle θ, the draw ratio, etc. given to the long stretched laminate to be manufactured. It can be finely adjusted manually or automatically. In the present invention, a long laminate is stretched, and the orientation angle θ can be set within a range of 45 ° ± 10 ° with respect to the winding direction after stretching.

  The traveling speed of the gripping tool can be selected as appropriate, but is usually in the range of 1 to 100 m / min. The difference in travel speed between the pair of left and right grippers is usually 1% or less, preferably 0.5% or less, more preferably 0.1% or less of the travel speed. This is because if there is a difference in the traveling speed between the left and right sides of the film at the exit of the stretching process, wrinkles and shifts will occur at the exit of the stretching process, so the speed difference between the right and left gripping tools is required to be substantially the same speed. Because. In general tenter devices, etc., there are speed irregularities that occur in the order of seconds or less depending on the period of the sprocket teeth driving the chain, the frequency of the drive motor, etc. It does not fall under the difference.

  Moreover, in the diagonally stretched tenter used in the present invention, it is preferable that the positions of the rail portions and the rail connecting portions can be freely set. Therefore, the oblique stretching tenter can be set to a stretching ratio according to an arbitrary entrance width and exit width. (In the figure, the part indicated by “◯” is a connecting part).

  In the obliquely stretched tenter used in the present invention, a large bending rate is often required for the rail that regulates the locus of the gripping tool. In order to avoid interference between gripping tools due to sudden bending or local stress concentration, it is desirable that the trajectory of the gripping tool draws an arc at the bent portion. In addition, the obliquely stretched tenter applied to the present invention has a mechanism for stretching so as to have an inclination of 45 ° ± 10 ° with respect to the transport direction, and is contracted by 10% to 40% in a direction perpendicular to the stretching axis. It is preferable that a mechanism capable of performing the above is provided.

  In the diagonally stretched tenter shown in FIG. 1A, the traveling direction 14-1 at the tenter inlet of the elongated laminate is the traveling direction 14-2 on the tenter exit side of the stretched laminate after stretching. Is different. The feeding angle θi is an angle formed by the traveling direction 14-1 at the tenter inlet and the traveling direction 14-2 on the tenter exit side of the stretched laminate after stretching.

  In the obliquely stretched tenter shown in FIG. 1B, the traveling direction 14-1 at the tenter inlet of the long laminate is different from the traveling direction at the tenter inlet at the feeding angle θi in the tenter. To be transported. Thereafter, the conveying direction is further changed, and finally the locus is taken so as to coincide with the traveling direction on the tenter exit side of the stretched laminate after stretching.

  In the present invention, as described above, in order to produce a stretched laminate having an orientation angle θ of 45 ° ± 10 ° with respect to the transport direction, the feeding angle θi is set in the range of 35 to 55 °. By setting the feeding angle θi in the above range, the variation in optical characteristics in the width direction of the obtained stretched laminate is improved (smaller).

  In the present invention, the gripping tool of the tenter is configured to travel at a constant speed with a certain distance from the front and rear gripping tools.

  (A-2) and (B-2) in FIG. 2 schematically show the stretching direction of the laminate in the oblique stretching tenter shown in (A) and (B) of FIG.

  In the present invention, as shown by (A-2) and (B-2) in FIG. 2, the both ends of the laminated body are gripped by the gripping tool for the first time, that is, the lamination on the introduction side from the gripping start points A1 and A1. Starting from two points B1 (that is, the film grip start point on the opposite side) where the straight line drawn substantially perpendicular to the center line of the body intersects the trajectory of the opposite gripping means, the gripping tools on both ends are substantially constant. When transported at a speed, the stretching end point An moves from A1 to A2 and A3 every unit time, and B1 similarly travels from B1 to B2 and B3 to the stretching end point Bn. By using such a stretching method, as shown in (A-2) and (B-2) of FIG. 2, the gripping portion An is gradually delayed with respect to Bn, so the stretching direction is the width direction. It gradually tilts from. The actual grip end point (the point at which the gripped transport film is released from the gripper that was gripped) is the point at which either or both ends of the transport film are released from the gripper, that is, the grip end A point Bx and a straight line drawn substantially perpendicularly to the center line of the stacked body sent from Bx to the next process are defined by two points Ay that intersect with the trajectory of the gripping means on the opposite side. Here, “substantially vertical” means within 90 ± 1 °.

  The angle in the stretching direction of the final laminate is determined by the distance W between the grip end points (the distance between Bx and Ay) and the ratio between Ax and Ay.

Therefore, the inclination angle θf formed by the stretching direction with respect to the transport direction to the next direction is
tan θf = W / (Ay−Ax)
That is,
tan θf = W / | LA-LB |
An angle that satisfies

  Here, LA is the travel distance from the grip start point to the grip end point on the tenter rail on the large turn side, and LB is the grip end on the tenter rail locus on the small turn side from the grip start point to the end of gripping. Is the distance traveled to the point, and | LA-LB | is the difference in the distance that the left and right grippers travel on the tenter rail at the grip end point.

  The definition of the draw ratio in the present invention will be described with reference to FIG.

In FIG. 2, the linear distance from the grip start point A1 to B1 at which the laminate is first gripped by the gripping tool in the oblique stretching tenter is Lo, and both of the gripping tools pass through all the stretching zones in the oblique stretching tenter. When the position of the gripping tool (stretching end point) is An and Bn, and the linear distance between An and Bn is L, the stretching ratio R of the laminate in the oblique stretching tenter is
R = L / L0
Defined by

  The draw ratio R at this time is preferably in the range of 2.0 to 7.0, more preferably in the range of 4.0 to 6.0. If the draw ratio is in this range, thickness unevenness in the width direction is reduced, which is preferable. In the stretching zone of the oblique stretching tenter, if the stretching temperature is differentiated in the width direction, the thickness unevenness in the width direction can be further improved.

  In the obliquely stretched tenter, as shown in FIG. 1, as shown in FIG. 1, the both ends (both sides) are sequentially held by the left and right gripping tools at the tenter inlet (position “a”). Traveled. At the tenter inlet (position a), the left and right gripping tools facing the direction substantially perpendicular to the traveling direction (14-1) of the laminate travel on the left-right asymmetric rail, and the preheating zone, It passes through an oven having a transverse stretching zone, an oblique stretching zone, a holding zone, and a cooling zone.

  However, it is not always necessary to transport the laminated body in the above order in all the zones. For example, as in the following combination examples, only a part of the zones is used, or any zone among the zones is several times. Or may be used.

1) Preheating zone / oblique stretching zone / holding zone / cooling zone 2) Preheating zone / oblique stretching zone / shrink zone / holding zone / cooling zone 3) Preheating zone / lateral stretching zone / oblique stretching zone / holding zone / cooling zone 4 ) Preheating zone / oblique stretching zone / lateral stretching zone / holding zone / cooling zone 5) Preheating zone / lateral stretching zone / oblique stretching zone / shrinking zone / holding zone / cooling zone 6) Preheating zone / oblique stretching zone / lateral stretching zone / Shrinking zone / Holding zone / Cooling zone The preheating zone refers to a section where the oven runs at the entrance of the oven while holding the gap between the grips at both ends of the laminate.

  The transverse stretching zone refers to a section in which the interval between the gripping tools that grip both ends of the laminate starts to reach a predetermined interval. At this time, the opening angle of the rail on which the gripping tools at both ends run may be opened at the same angle for both rails, or may be opened at different angles.

  The diagonally extending zone refers to a gripping tool that grips both ends of the laminate, while the gripping tool spacing is kept constant or spreads, and both gripping tools travel on a straight rail again. This refers to the interval until you begin to do.

  The contraction zone refers to a section in which the interval between gripping tools gripping both ends of the laminate is narrowed in a direction perpendicular to the stretching axis and reaches a predetermined interval.

  The holding zone refers to a section in which the gripping tools at both ends travel while being parallel to each other in a period in which the interval between the gripping tools after the transverse stretching zone or the oblique stretching zone becomes constant again.

  The cooling zone refers to a section where the temperature in the zone is set to the glass transition temperature Tg ° C. or lower of the thermoplastic resin constituting the laminate in the section after the holding zone.

  At this time, in consideration of shrinkage of the stacked body due to cooling, a rail pattern that narrows the gap between the opposing gripping tools in advance may be used.

  The temperature of each zone is Tg to Tg + 30 ° C., the temperature of the stretching zone is Tg to Tg + 30 ° C., and the temperature of the cooling zone is Tg−30 to Tg ° C. with respect to the glass transition temperature Tg of the thermoplastic resin layer. It is preferable to set the range.

  In order to control the thickness unevenness in the width direction, a temperature difference may be applied in the width direction in the stretching zone. Examples of a method of imparting a temperature difference in the width direction in the stretching zone include, for example, a method of adjusting the opening degree of the nozzle that sends warm air into the temperature-controlled room so as to make a difference in the width direction, and heating by arranging heaters in the width direction. A known method such as control can be used.

  Furthermore, as a method of preventing the occurrence of wrinkles and misalignment in the stretched laminate, the support of the laminate is maintained during stretching, and after stretching in a state where the volatile content is 5% by volume or more, it is volatilized while shrinking. The method etc. which reduce a fraction can be mentioned. Maintaining the support of the laminate in the present invention means that both side edges are gripped without impairing the film properties of the laminate. As for the volatile content, the state of 5% by volume or more may always be maintained in the stretching operation process, and the state of the volatile content is maintained at 5% by volume or more only in a part of the stretching operation process. May be. In the latter case, it is preferable that the entrance position is a starting point, and that the section of 50% or more of the entire stretching section and the volatile content rate are 12% by volume or more. In any case, it is preferable to have a volatile content of 12% by volume or more before stretching. Here, the volatile fraction (unit: volume%) represents the volume of the volatile component contained per unit volume of the film, and is a value obtained by dividing the volatile component volume by the film volume.

  The guide roller closest to the entrance of the tenter is a driven roller that guides the travel of the laminated body, and is rotatably supported by bearings via bearings. Known materials can be used for the roller, but it is preferable to reduce the weight, such as a method of applying a ceramic coat to prevent the laminate from being damaged, a method of applying chrome plating to a light metal such as aluminum, and the like. is there. This roller is provided to stabilize the track during travel of the laminate.

  Further, it is preferable that one of the rollers on the upstream side of the roller is nipped by pressing a rubber roller. This is because by using such a nip roller, it is possible to suppress fluctuations in the feeding tension in the flow direction of the laminate.

  A pair of bearing portions at both ends (left and right) of the guide roller closest to the entrance of the tenter includes a first laminate tension detecting device for detecting tension generated in the laminate being conveyed in the roller, Two laminate tension detecting devices are provided. As the laminate tension detection device, for example, a load cell can be used. As the load cell, a known tensile or compression type can be used. A load cell is a device that detects a load acting on an applied point by converting it into an electrical signal using a strain gauge attached to the strain generating body.

  The load cell is installed on the left and right bearings of the guide roller closest to the entrance of the obliquely stretched tenter, so that the force exerted on the roller by the traveling laminate, that is, the progress of the laminate occurring near both side edges of the laminate The tension in the direction is detected independently on the left and right. In addition, a strain gauge may be directly attached to the support that constitutes the roller bearing portion, and the load, that is, the laminate tension may be detected based on the strain generated in the support. The relationship between the generated strain and the laminate tension is measured in advance and is known.

  The laminated body tension detection device as described above is provided so that the tension in the vicinity of both side edges of the laminated body in the guide roller closest to the entrance of the obliquely stretched tenter is detected because the position and direction of the laminated body When there is a deviation with respect to the position and direction of the inlet portion of the body stretching device, a difference is generated in the tension in the vicinity of both side edges of the laminated body in the guide roller closest to the inlet of the oblique stretching tenter according to the amount of the deviation. Therefore, by detecting this tension difference, the degree of the deviation is discriminated. If the position and direction of the laminated body are appropriate in relation to the position and direction of the inlet portion of the laminated body stretching apparatus, the load acting on the roller is roughly equal on the left and right, and if the positions are shifted, the left and right A difference occurs in the tension of the laminate.

  Therefore, if the position and angle of the laminate are appropriately adjusted so that the difference in tension between the left and right laminates at the guide roller closest to the entrance of the oblique stretching tenter is equal, the gripper at the entrance of the laminate stretching apparatus Grasping is stable and the occurrence of obstacles such as detachment of the gripping tool can be reduced. Furthermore, the physical properties in the width direction of the laminate after oblique stretching by the laminate stretching apparatus can be stabilized.

  In order to cope with fine adjustment of the orientation angle and product variations, it is necessary to adjust the angle formed by the laminate travel direction at the obliquely stretched tenter inlet and the laminate travel direction at the obliquely stretched tenter outlet. At that time, as described above, it is preferable from the viewpoint of productivity and yield that the laminated body is formed and obliquely stretched continuously. When the laminated body forming process, the oblique stretching process, and the winding process are performed continuously, the traveling direction of the laminated body in the laminated body forming process and the winding process is the same in that the width of the process can be reduced. preferable. For such a process, in order to guide the laminated laminate to the obliquely stretched tenter inlet, to change the transport direction of the laminated body, or to return the laminated body that has exited from the obliquely stretched tenter outlet to the winding device direction. In addition, a method for changing the transport direction of the laminate is required. As a device for changing the transport direction of the laminated body, a known method such as using an air flow roller can be used. It is preferable that a device (winding device, accumulator device, drive device, etc.) after the obliquely extending tenter exit is slidable in the lateral direction.

  Next, another method for producing a stretched laminate according to the present invention will be described with reference to the drawings.

  3A to 3C are schematic views showing an example of another method for producing a stretched laminate according to the present invention (an example in which the stretched laminate is drawn from a long laminate roll and then obliquely stretched).

  4 (A) and 4 (B) are schematic views showing an example of another method for producing a stretched laminate according to the present invention (an example of continuous oblique stretching without winding up a long laminate film). is there.

  3 (A) to 3 (C) show an example of a pattern in which a long laminate once wound up in a roll shape is drawn out and obliquely stretched, and FIGS. 4 (A) and 4 (B). These show an example of the pattern which performs a diagonal stretch process continuously, without winding up each elongate laminated body raw material.

  In FIG. 3, 16 is a laminated body feeding device, 17 is a conveying direction changing device, 18 is a winding device, and 19 is a film forming device. In each figure, symbols indicating the same thing may be omitted.

  The laminated body feeding device 16 is slidable and swivel so that the laminated body can be fed out at a predetermined angle with respect to the obliquely extending tenter inlet, or the laminated body feeding device 16 is slidable, and the conveying direction It is preferable that the change body 17 can feed the laminate to the entrance of the obliquely stretched tenter. By configuring the laminate feeding device 16 and the conveyance direction changing device 17 as described above, the width of the entire manufacturing apparatus can be further reduced, and the feeding position and angle of the laminate can be finely controlled. Thus, it becomes possible to obtain a stretched laminate having small variations in film thickness and optical value. In addition, by enabling movement of the stacked body feeding device 16 and the conveyance direction changing device 17, it is possible to effectively prevent the left and right clips from being caught in the stacked body.

[Preparation of polarizing plate]
The 1st protective film mentioned later is bonded to the surface on the opposite side to the surface by the side of the thermoplastic resin layer of the polarizer layer of the laminated body produced according to the said method. Examples of the method of bonding the first protective film include a method of bonding the polarizer layer and the first protective film with an adhesive, and a method of bonding the polarizer layer and the first protective film with an adhesive. It is done.

  After bonding, the thermoplastic resin layer may be used as it is as a protective film (corresponding to a second protective film described later), but it is preferable to peel the thermoplastic resin layer from the laminate. The peeling method of a thermoplastic resin layer is not specifically limited, It can peel by the method similar to the peeling process of the peeling film performed with the polarizing plate with a normal adhesive. After laminating the first protective film, it may be peeled off as it is, or after winding it up into a roll once, it may be peeled off by providing a separate peeling step.

[First protective film]
Subsequently, the 1st protective film which comprises the circularly-polarizing plate of this invention is demonstrated.

  The first protective film according to the present invention has a condition defined by the following formula (i) in the measurement at an optical wavelength of 590 nm in an environment where the in-plane retardation value Ro is 23 ° C. and relative humidity 55% RH. The angle between the slow axis of the first protective film and the absorption axis of the polarizer according to the present invention is 45 ° ± 10 °.

Formula (i)
80 ≦ Ro ≦ 200
In the above formula (i), the birefringence and retardation value of the film can be measured using an automatic birefringence measuring apparatus (trade name KOBRA-21ADH manufactured by Oji Scientific Instruments), but is limited to this. is not.

  Although the 1st protective film which concerns on this invention will not be limited if the phase difference Ro of an in-plane direction is a material in said range, It is preferable that it is a protective film which consists of a cellulose-ester film.

A more preferred cellulose ester has an acyl group having 2 to 4 carbon atoms as a substituent, the substitution degree of the acetyl group is _Xac, and the substitution degree of the propionyl group or butyryl group is _Ypb . the sum of the substitution degree and Y _pb of the substitution degree X _ac and professional and Pioniru group or butyryl group, a satisfying cellulose ester defined by the following formula (a).

  In addition, it is preferable that the thickness direction retardation Rt is in the range of 100 ≦ Rt ≦ 300 in order to exhibit the effects of the present invention.

Formula (A)
2.2 ≦ (X _ac + Y _pb ) ≦ 2.55
Particularly preferred is a cellulose ester that simultaneously satisfies the above formula (A) and the following formula (B).

Formula (B)
1.0 ≦ X _ac ≦ 2.1, 0.1 ≦ Y _pb ≦ 1.55
The degree of substitution of these acyl groups can be measured according to the method prescribed in ASTM-D817-96. The portion not substituted with an acyl group is usually present as a hydroxy hydroxyl group.

  These cellulose esters can be synthesized by a known method.

  Cellulose as a raw material for the cellulose ester used in the first protective film according to the present invention can be used in the same manner as cellulose as a raw material for the cellulose ester used in the thermoplastic resin layer or the second protective film. The molecular weight, Mw / Mn ratio, and measurement method of the cellulose ester used in the first protective film according to the present invention are the same as those of the thermoplastic resin layer (second protective film).

  In the present invention, the angle formed between the slow axis of the first protective film and the absorption axis of the polarizer is 45 ° ± 10 °. For this configuration, the slow axis of the first protective film is preferably parallel or perpendicular to the longitudinal direction of the roll-shaped polarizing plate. From the viewpoint of ease of production, etc., it is preferably perpendicular to the longitudinal direction.

  By making the first protective film and the polarizer as described above, linearly polarized light that has passed through the polarizer from the light source side can be made into a circularly polarizing plate by the first protective film (ie, λ / 4 plate). It is. In addition, according to the configuration of the present invention, a roll-shaped polarizer in which the angle between the longitudinal direction and the absorption axis is substantially 45 °, and a roll-shaped λ in which the longitudinal direction and the slow axis are substantially perpendicular. A roll-shaped circularly polarizing plate can be easily produced by simply laminating a / 4 plate with a roll-to-roll.

  Although the film thickness of a 1st protective film is not specifically limited, 10-200 micrometers is used. Preferably it is 10-100 micrometers, More preferably, it is 30-80 micrometers.

<Phase difference adjusting agent>
In the present invention, a phase difference adjusting agent can be used to adjust the phase difference. Although it does not specifically limit as a phase difference adjusting agent, The following polyester polyol can be used.

  The polyester polyol that can be used in the present invention is a polymer in which the terminal that can be obtained by the condensation reaction of dibasic acid or an ester-forming derivative thereof and glycol becomes a hydroxy group (hydroxyl group). The ester-forming derivatives referred to here are esterified products of dibasic acids, dibasic acid chlorides, and anhydrides of dibasic acids.

  The polyester polyol is obtained by dehydration condensation reaction of aromatic dibasic acid and glycol, addition of glycol to aromatic anhydride dibasic acid and dehydration condensation reaction, or dealcoholization of esterified product of aromatic dibasic acid and glycol. It can be obtained by a condensation reaction.

  As the aromatic dibasic acid or an ester-forming derivative thereof, an aromatic dicarboxylic acid having 10 to 16 carbon atoms or an ester-forming derivative thereof can be used. For example, a benzene ring structure, a naphthalene ring structure, Dicarboxylic acids having an aromatic ring structure such as anthracene ring structure and ester-forming derivatives thereof can be used. For example, orthophthalic acid having a substituent, isophthalic acid having a substituent, terephthalic acid having a substituent, substituted Group-containing phthalic anhydride, 1,4-naphthalenedicarboxylic acid, 2,3-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, 1,8-naphthalenedicarboxylic acid, 2,6 -Anthracene dicarboxylic acid, etc., their esterified products, acid chlorides, 1,8-na Etc. can be mentioned acid anhydrides data dicarboxylic acids, they may have a substituent on the aromatic ring, can be used in combination use of two or more of these alone. 1,4-naphthalenedicarboxylic acid, 2,3-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, 1,8-naphthalenedicarboxylic acid and esterified products thereof, 2,3-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid and esterified products thereof are preferable, and 2,6-naphthalenedicarboxylic acid and esterified products thereof are particularly preferable.

  The average of the carbon number of the dibasic acid of the polyester polyol means the carbon number of the dibasic acid when the polyester polyol is polymerized using a single dibasic acid. When the polyester polyol is polymerized using, it means the sum of the products of the carbon number of each dibasic acid and the molar fraction of the dibasic acid.

  In the present invention, it is important that the average number of carbon atoms of the dibasic acid used as a raw material for the polyester polyol is in the range of 10 to 16. If the average carbon number of the dibasic acid is 10 or more, the retardation is excellent. If the average carbon number is 16 or less, the compatibility with the cellulose ester is remarkably excellent. As a dibasic acid, Preferably the average of carbon number is 10-14, More preferably, the average of carbon number is 10-12.

  If the average carbon number is 10 to 16, the aromatic dibasic acid having 10 to 16 carbon atoms and the other dibasic acid can be used in combination.

  The dibasic acid that can be used in combination is preferably a dicarboxylic acid having 4 to 9 carbon atoms or an ester-forming derivative thereof. For example, succinic acid, glutaric acid, adipic acid, maleic acid, succinic anhydride, maleic anhydride, orthophthalic acid Examples thereof include acids, isophthalic acid, terephthalic acid, phthalic anhydride and the like, esterified products, and acid chlorides thereof.

  Examples of the glycol include ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propanediol, 2-methyl 1,3-propanediol, 1,2-butanediol, 1,3. -Butanediol, 1,4-butanediol, 2,3-butanediol, 1,5-pentanediol, neopentyl glycol, 1,2-cyclopentanediol, 1,3-cyclopentanediol, 1,4-cyclohexane Diols can be used alone or in combination of two or more. Among them, ethylene glycol, diethylene glycol, 1,2-propylene glycol and 2-methyl 1,3-propanediol are preferable, and ethylene glycol and diethylene glycol are more preferable. 1, - propylene glycol.

  In the present invention, the polyester polyol is a dibasic acid or an ester-forming derivative thereof and a glycol, if necessary, in the presence of an esterification catalyst, for example, within a temperature range of 180 to 250 ° C., for 10 to 25 hours. It can be produced by an esterification reaction by a well-known and usual method.

  In conducting the esterification reaction, a solvent such as toluene or xylene may be used, but a method using no solvent or glycol used as a raw material as a solvent is preferable.

  As the esterification catalyst, for example, tetraisopropyl titanate, tetrabutyl titanate, p-toluenesulfonic acid, dibutyltin oxide and the like can be used. The esterification catalyst is preferably used in an amount of 0.01 to 0.5 parts by mass with respect to 100 parts by mass of the total amount of dibasic acids or their ester-forming derivatives.

  The molar ratio of the dibasic acid or the ester-forming derivative thereof to the glycol must be such that the terminal group of the polyester is a hydroxy group (hydroxyl group). The glycol is 1.1 to 10 moles per mole of the functional derivative. Preferably, glycol is 1.5 to 7 moles per mole of dibasic acid or ester-forming derivative thereof, and more preferably, 1 mole of dibasic acid or ester-forming derivative thereof. 2-5 moles of glycol.

  On the other hand, since the carboxyl group terminal in the said polyester polyol reduces humidity stability, the one where the content is low is preferable. Specifically, the acid value is preferably 5.0 or less, more preferably 1.0 or less, and particularly preferably 0.5 or less.

  The acid value referred to here means the number of milligrams of potassium hydroxide necessary for neutralizing the acid (carboxy group present in the sample) contained in 1 g of the sample. The acid value is measured according to JIS K0070.

  The polyester polyol preferably has a hydroxy group (hydroxyl group) value (OHV) in the range of 35 mgKOH / g to 220 mgKOH / g. The hydroxy group (hydroxyl group) value referred to here is the number of milligrams of potassium hydroxide required to neutralize acetic acid bonded to the hydroxy group (hydroxyl group) when OH groups contained in 1 g of a sample are acetylated. Say. Acetic anhydride is used to acetylate OH groups in the sample, and unused acetic acid is titrated with a potassium hydroxide solution, and obtained from the difference from the initial titration value of acetic anhydride.

  The polyester polyol preferably has a hydroxy group (hydroxyl group) content of 70% or more. When the hydroxy group (hydroxyl group) content is low, the compatibility between the polyester polyol and the cellulose ester is lowered. For this reason, the hydroxy group (hydroxyl group) content is preferably 70% or more, more preferably 90% or more, and most preferably 99% or more.

  In the present invention, a compound having a hydroxy group (hydroxyl group) content of 50% or less is not included in the polyester polyol because one of the end groups is substituted with a group other than the hydroxy group (hydroxyl group).

  The hydroxy group (hydroxyl group) content can be determined by the following formula (A).

Formula (A)
Y / X × 100 = hydroxy group (hydroxyl group) content (%)
X: Hydroxyl group (hydroxyl group) value (OHV) of the polyester polyol
Y: 1 / (number average molecular weight (Mn)) × 56 × 2 × 1000
The polyester polyol preferably has a number average molecular weight within a range of 300 to 3,000, and more preferably has a number average molecular weight of 350 to 2,000.

  Moreover, it is preferable that the dispersion degree of the molecular weight of the polyester polyol based on this invention is 1.0-3.0, and it is still more preferable that it is 1.0-2.0. If the degree of dispersion is within the above range, a polyester polyol having excellent compatibility with the cellulose ester can be obtained.

  The polyester polyol preferably contains 50% or more of a component having a molecular weight of 300 to 1800. By setting the number average molecular weight within the above range, the compatibility can be greatly improved.

  As a method for controlling the number average molecular weight, the degree of dispersion, and the component content within the above preferable range, 2 to 5 mol of glycol is used per 1 mol of dibasic acid or ester-forming derivative thereof, and unreacted glycol is used. A method of distilling off under reduced pressure is preferred. The temperature at which the solvent is distilled off under reduced pressure is preferably 100 to 200 ° C, more preferably 120 to 180 ° C, and particularly preferably 130 to 170 ° C. The degree of reduced pressure when distilled off under reduced pressure is preferably 13.3 Pa to 66.5 kPa, more preferably within the range of 13.3 Pa to 26.6 kPa, and most preferably within the range of 13.3 Pa to 13.3 kPa. is there.

  The polyester polyol number average molecular weight (Mn) and dispersity can be measured using gel permeation chromatography (GPC).

  An example of measurement conditions is as follows, but is not limited to this, and an equivalent measurement method can be used.

Solvent: Tetrahydrofuran (THF)
Column: TSKgel G2000HXL (Tosoh Co., Ltd. uses two connected)
Column temperature: 40 ° C
Sample concentration: 0.1% by mass
Apparatus: HLC-8220 (manufactured by Tosoh Corporation)
Flow rate: 1.0ml / min
Calibration curve: A calibration curve by PStQuick F (manufactured by Tosoh Corporation) is used.

  In obtaining the effects of the present invention, the polyester polyol is preferably contained in the film in an amount of 5 to 30% by mass. More preferably, it is 5-20 mass%.

  Specific examples of dibasic acids having 10 to 16 carbon atoms are shown below, but the present invention is not limited thereto.

(1) 2,6-naphthalenedicarboxylic acid (2) 2,3-naphthalenedicarboxylic acid (3) 2,6-anthracenedicarboxylic acid (4) 2,6-naphthalenedicarboxylic acid: succinic acid (75: 25-99: 1 molar ratio)
(5) 2,6-naphthalenedicarboxylic acid: terephthalic acid (50:50 to 99: 1 molar ratio)
(6) 2,3-naphthalenedicarboxylic acid: succinic acid (75:25 to 99: 1 molar ratio)
(7) 2,3-naphthalenedicarboxylic acid: terephthalic acid (50:50 to 99: 1 molar ratio)
(8) 2,6-anthracene dicarboxylic acid: succinic acid (50:50 to 99: 1 molar ratio)
(9) 2,6-anthracene dicarboxylic acid: terephthalic acid (25:75 to 99: 1 molar ratio)
(10) 2,6-naphthalenedicarboxylic acid: adipic acid (67:33 to 99: 1 molar ratio)
(11) 2,3-naphthalenedicarboxylic acid: adipic acid (67:33 to 99: 1 molar ratio)
(12) 2,6-anthracene dicarboxylic acid: adipic acid (40:60 to 99: 1 molar ratio)
As the phase difference adjusting agent that can be used in the present invention, in addition to the above-mentioned polyester polyol, a compound having an octanol-water partition coefficient (log P) of 0 or more and less than 7 is used from the viewpoint of water solubility and orientation of the compound. Is also preferable.

  As the phase difference adjusting agent, for example, an ester compound represented by the following general formula (3) can be preferably used.

General formula (3)
B- (GA) n-GB
In the general formula (3), B is a hydroxy group or a carboxylic acid residue, G is an alkylene glycol residue having 2 to 12 carbon atoms, an aryl glycol residue having 6 to 12 carbon atoms, or an oxy having 4 to 12 carbon atoms. An alkylene glycol residue, A represents an alkylene dicarboxylic acid residue having 4 to 12 carbon atoms or an aryl dicarboxylic acid residue having 6 to 12 carbon atoms, and n represents an integer of 1 or more. )
In the general formula (3), a hydroxy group or a carboxylic acid residue represented by B, an alkylene glycol residue, an oxyalkylene glycol residue or an aryl glycol residue represented by G, an alkylene dicarboxylic acid residue represented by A or It is composed of an aryl dicarboxylic acid residue and can be obtained by the same reaction as that of a normal ester compound.

  Examples of the carboxylic acid component of the ester compound represented by the general formula (3) include acetic acid, propionic acid, butyric acid, benzoic acid, p-tert-butylbenzoic acid, orthotoluic acid, metatoluic acid, p-toluic acid, and dimethylbenzoic acid. , Ethyl benzoic acid, normal propyl benzoic acid, aminobenzoic acid, acetoxybenzoic acid, aliphatic acid and the like, and these can be used as one kind or a mixture of two or more kinds, respectively.

  Examples of the alkylene glycol component having 2 to 12 carbon atoms of the ester compound represented by the general formula (3) include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,2-butanediol, , 3-butanediol, 1,2-propanediol, 2-methyl 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 2,2-dimethyl-1,3-propanediol ( Neopentyl glycol), 2,2-diethyl-1,3-propanediol (3,3-dimethylolpentane), 2-n-butyl-2-ethyl-1,3-propanediol (3,3-dimethylolheptane) ), 3-methyl-1,5-pentanediol 1,6-hexanediol, 2,2,4-trimethyl 1,3-pentanedioe , 2-ethyl 1,3-hexanediol, 2-methyl 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,12-octadecanediol, and the like. It is used as one kind or a mixture of two or more kinds.

  In particular, an alkylene glycol having 2 to 12 carbon atoms is particularly preferable because of excellent compatibility with a cellulose ester.

  Examples of the oxyalkylene glycol component having 4 to 12 carbon atoms of the ester compound represented by the general formula (3) include diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, and tripropylene glycol. Yes, these glycols can be used as one or a mixture of two or more.

  Examples of the alkylene dicarboxylic acid component having 4 to 12 carbon atoms of the ester compound represented by the general formula (3) include succinic acid, maleic acid, fumaric acid, glutaric acid, adipic acid, azelaic acid, sebacic acid, and dodecane. There exist dicarboxylic acid etc., and these are each used as a 1 type, or 2 or more types of mixture. Examples of the arylene dicarboxylic acid component having 6 to 12 carbon atoms include phthalic acid, terephthalic acid, isophthalic acid, 1,5 naphthalene dicarboxylic acid, and 1,4 naphthalene dicarboxylic acid.

  The ester compound represented by the general formula (3) has a number average molecular weight of preferably 300 to 1500, more preferably 400 to 1000. The acid value is 0.5 mgKOH / g or less, the hydroxy group (hydroxyl group) value is 25 mgKOH / g or less, more preferably the acid value is 0.3 mgKOH / g or less, and the hydroxy group (hydroxyl group) value is 15 mgKOH / g or less. Is.

  It is preferable that the 1st protective film which concerns on this invention, or the 2nd protective film mentioned later contains 0.1-30 mass% of retardation adjusting agents, and contains 0.5-10 mass% especially of a protective film. It is preferable.

(Phase difference agent)
In the present invention, a retardation (also referred to as “retardation”) developing agent may be included. A retardation developing agent can be contained, for example, within a range of 0.5 to 10% by mass of the first protective film, and further within a range of 2 to 6% by mass. Is preferred. By employing a phase difference (retardation) developing agent, high retardation expression can be obtained at a low draw ratio. The type of the retardation (retardation) developing agent is not particularly defined, and examples thereof include those composed of rod-like or discotic compounds. As the rod-like or discotic compound, a compound having at least two aromatic rings can be preferably used as a retardation developing agent. The addition amount of the retardation developing agent composed of the rod-shaped compound is preferably 0.5 to 10 parts by mass, and 2 to 6 parts by mass with respect to 100 parts by mass of the polymer component containing the cellulose ester. Is more preferable.

  The discotic retardation developing agent is preferably used in a range of 0.5 to 10 parts by mass, and in a range of 1 to 8 parts by mass with respect to 100 parts by mass of the polymer component containing the cellulose ester. It is more preferable to use in the range of 2 to 6 parts by mass.

  Two or more kinds of retardation developing agents may be used in combination.

  The phase difference (retardation) developing agent preferably has maximum absorption in the wavelength region of 250 to 400 nm, and preferably has substantially no absorption in the visible region.

  The discotic compound will be described. As the discotic compound, a compound having at least two aromatic rings can be used.

  Here, the “aromatic ring” includes an aromatic heterocycle in addition to an aromatic hydrocarbon ring.

  The aromatic hydrocarbon ring is particularly preferably a 6-membered ring (that is, a benzene ring).

  The aromatic heterocycle is generally an unsaturated heterocycle. The aromatic heterocycle is preferably a 5-membered ring, 6-membered ring or 7-membered ring, more preferably a 5-membered ring or 6-membered ring. Aromatic heterocycles generally have the most double bonds. As the hetero atom, a nitrogen atom, an oxygen atom and a sulfur atom are preferable, and a nitrogen atom is particularly preferable. Examples of aromatic heterocycles include furan ring, thiophene ring, pyrrole ring, oxazole ring, isoxazole ring, thiazole ring, isothiazole ring, imidazole ring, pyrazole ring, furazane ring, triazole ring, pyran ring, pyridine ring , Pyridazine ring, pyrimidine ring, pyrazine ring and 1,3,5-triazine ring.

  As the aromatic ring, a benzene ring, a condensed benzene ring, and biphenyls are preferable. In particular, a 1,3,5-triazine ring is preferably used. Specifically, for example, compounds disclosed in JP-A No. 2001-166144 are preferably used.

  The number of carbon atoms of the aromatic ring contained in the retardation developing agent is preferably 2-20, more preferably 2-12, further preferably 2-8, and 2-6. Most preferably.

  The bonding relationship between two aromatic rings can be classified into (a) when forming a condensed ring, (b) when directly connecting with a single bond, and (c) when connecting via a linking group (for aromatic rings). , Spiro bonds cannot be formed). The connection relationship may be any of (a) to (c).

  Examples of the condensed ring (a condensed ring of two or more aromatic rings) include an indene ring, a naphthalene ring, an azulene ring, a fluorene ring, a phenanthrene ring, an anthracene ring, an acenaphthylene ring, a biphenylene ring, a naphthacene ring, Pyrene ring, indole ring, isoindole ring, benzofuran ring, benzothiophene ring, indolizine ring, benzoxazole ring, benzothiazole ring, benzimidazole ring, benzotriazole ring, purine ring, indazole ring, chromene ring, quinoline ring, isoquinoline Ring, quinolidine ring, quinazoline ring, cinnoline ring, quinoxaline ring, phthalazine ring, pteridine ring, carbazole ring, acridine ring, phenanthridine ring, xanthene ring, phenazine ring, phenothiazine ring, phenoxathiin ring, phenoxazine ring and thiantole Ring, and the like. Among these, naphthalene ring, azulene ring, indole ring, benzoxazole ring, benzothiazole ring, benzimidazole ring, benzotriazole ring and quinoline ring are preferable.

  The single bond (b) is preferably a bond between carbon atoms of two aromatic rings. Two aromatic rings may be bonded with two or more single bonds to form an aliphatic ring or a non-aromatic heterocyclic ring between the two aromatic rings.

  The linking group in (c) is also preferably bonded to carbon atoms of two aromatic rings. The linking group is preferably an alkylene group, an alkenylene group, an alkynylene group, —CO—, —O—, —NH—, —S—, or a combination thereof.

  Examples of linking groups composed of combinations are shown below. In addition, the relationship between the left and right in the following examples of the linking group may be reversed.

c1: -CO-O-
c2: —CO—NH—
c3: -alkylene-O-
c4: —NH—CO—NH—
c5: —NH—CO—O—
c6: —O—CO—O—
c7: -O-alkylene-O-
c8: -CO-alkenylene-
c9: -CO-alkenylene-NH-
c10: -CO-alkenylene-O-
c11: -alkylene-CO-O-alkylene-O-CO-alkylene-
c12: -O-alkylene-CO-O-alkylene-O-CO-alkylene-O-
c13: -O-CO-alkylene-CO-O-
c14: -NH-CO-alkenylene-
c15: -O-CO-alkenylene-
The aromatic ring and the linking group may have a substituent.

  Examples of substituents include halogen atoms (F, Cl, Br, I), hydroxy groups, carboxy groups, cyano groups, amino groups, nitro groups, sulfo groups, carbamoyl groups, sulfamoyl groups, ureido groups, alkyl groups, alkenyls. Group, alkynyl group, aliphatic acyl group, aliphatic acyloxy group, alkoxy group, alkoxycarbonyl group, alkoxycarbonylamino group, alkylthio group, alkylsulfonyl group, aliphatic amide group, aliphatic sulfonamido group, aliphatic substituted amino group An aliphatic substituted carbamoyl group, an aliphatic substituted sulfamoyl group, an aliphatic substituted ureido group, and a non-aromatic heterocyclic group.

  It is preferable that the alkyl group has 1 to 8 carbon atoms. A chain alkyl group is preferable to a cyclic alkyl group, and a linear alkyl group is particularly preferable. The alkyl group may further have a substituent (for example, a hydroxy group, a carboxy group, an alkoxy group, an alkyl-substituted amino group). Examples of alkyl groups (including substituted alkyl groups) include methyl, ethyl, n-butyl, n-hexyl, 2-hydroxyethyl, 4-carboxybutyl, 2-methoxyethyl and 2-methoxyethyl. Each group of a diethylaminoethyl group is included.

  The alkenyl group preferably has 2 to 8 carbon atoms. A chain alkenyl group is preferable to a cyclic alkenyl group, and a linear alkenyl group is particularly preferable. The alkenyl group may further have a substituent. Examples of the alkenyl group include a vinyl group, an allyl group, and a 1-hexenyl group.

  The alkynyl group preferably has 2 to 8 carbon atoms. A chain alkynyl group is preferable to a cyclic alkynyl group, and a linear alkynyl group is particularly preferable. The alkynyl group may further have a substituent. Examples of the alkynyl group include ethynyl group, 1-butynyl group and 1-hexynyl group.

  The number of carbon atoms in the aliphatic acyl group is preferably 1-10. Examples of the aliphatic acyl group include an acetyl group, a propanoyl group, and a butanoyl group.

  The number of carbon atoms in the aliphatic acyloxy group is preferably 1-10. Examples of the aliphatic acyloxy group include an acetoxy group.

  The number of carbon atoms of the alkoxy group is preferably 1-8. The alkoxy group may further have a substituent (for example, an alkoxy group). Examples of the alkoxy group (including a substituted alkoxy group) include a methoxy group, an ethoxy group, a butoxy group, and a methoxyethoxy group.

  The number of carbon atoms of the alkoxycarbonyl group is preferably 2-10. Examples of the alkoxycarbonyl group include a methoxycarbonyl group and an ethoxycarbonyl group.

  The number of carbon atoms of the alkoxycarbonylamino group is preferably 2-10. Examples of the alkoxycarbonylamino group include a methoxycarbonylamino group and an ethoxycarbonylamino group.

  The alkylthio group preferably has 1 to 12 carbon atoms. Examples of the alkylthio group include a methylthio group, an ethylthio group, and an octylthio group.

  The alkylsulfonyl group preferably has 1 to 8 carbon atoms. Examples of the alkylsulfonyl group include a methanesulfonyl group and an ethanesulfonyl group.

  The number of carbon atoms in the aliphatic amide group is preferably 1-10. Examples of the aliphatic amide group include acetamide.

  The number of carbon atoms of the aliphatic sulfonamide group is preferably 1-8. Examples of the aliphatic sulfonamido group include a methanesulfonamido group, a butanesulfonamido group, and an n-octanesulfonamido group.

  The number of carbon atoms of the aliphatic substituted amino group is preferably 1-10. Examples of the aliphatic substituted amino group include a dimethylamino group, a diethylamino group, and a 2-carboxyethylamino group.

  The number of carbon atoms in the aliphatic substituted carbamoyl group is preferably 2-10. Examples of the aliphatic substituted carbamoyl group include a methylcarbamoyl group and a diethylcarbamoyl group.

  The number of carbon atoms in the aliphatic substituted sulfamoyl group is preferably 1-8. Examples of the aliphatic substituted sulfamoyl group include a methylsulfamoyl group and a diethylsulfamoyl group.

  The number of carbon atoms in the aliphatic substituted ureido group is preferably 2-10. Examples of the aliphatic substituted ureido group include a methylureido group.

  Examples of the non-aromatic heterocyclic group include a piperidino group and a morpholino group.

  The molecular weight of the retardation developing agent is preferably 300 to 800.

  It is preferable to use a triazine compound represented by the following general formula (4) as the discotic compound.

In the general formula (4), each R ¹ independently represents an aromatic ring or a heterocyclic ring having a substituent in at least one of the ortho position, the meta position, and the para position.

X each independently represents a single bond or NR ² —. Here, each R ² independently represents a hydrogen atom, a substituted or unsubstituted alkyl group, an alkenyl group, an aryl group, or a heterocyclic group.

The aromatic ring represented by R ¹ is preferably phenyl or naphthyl, and particularly preferably phenyl. The aromatic ring represented by R ¹ may have at least one substituent at any substitution position. Examples of the substituent include a halogen atom, hydroxy group, cyano group, nitro group, carboxy group, alkyl group, alkenyl group, aryl group, alkoxy group, alkenyloxy group, aryloxy group, acyloxy group, alkoxycarbonyl group, Alkenyloxycarbonyl group, aryloxycarbonyl group, sulfamoyl group, alkyl-substituted sulfamoyl group, alkenyl-substituted sulfamoyl group, aryl-substituted sulfamoyl group, sulfonamide group, carbamoyl, alkyl-substituted carbamoyl group, alkenyl-substituted carbamoyl group, aryl-substituted carbamoyl group, amide Groups, alkylthio groups, alkenylthio groups, arylthio groups and acyl groups.

The heterocyclic group represented by R ¹ preferably has aromaticity. The heterocycle having aromaticity is generally an unsaturated heterocycle, preferably a heterocycle having the largest number of double bonds. The heterocyclic ring is preferably a 5-membered ring, 6-membered ring or 7-membered ring, more preferably a 5-membered ring or 6-membered ring, and most preferably a 6-membered ring. The hetero atom of the heterocyclic ring is preferably a nitrogen atom, a sulfur atom or an oxygen atom, and particularly preferably a nitrogen atom. As the heterocyclic ring having aromaticity, a pyridine ring (2-pyridyl or 4-pyridyl as the heterocyclic group) is particularly preferable. The heterocyclic group may have a substituent. Examples of the substituent of the heterocyclic group are the same as the examples of the substituent of the aryl moiety.

  When X is a single bond, the heterocyclic group is preferably a heterocyclic group having a free valence on the nitrogen atom. The heterocyclic group having a free valence on the nitrogen atom is preferably a 5-membered ring, 6-membered ring or 7-membered ring, more preferably a 5-membered ring or 6-membered ring, and a 5-membered ring. Is most preferred. The heterocyclic group may have a plurality of nitrogen atoms. Further, the heterocyclic group may have a hetero atom other than the nitrogen atom (for example, O, S). Examples of heterocyclic groups having free valences on nitrogen atoms are shown below.

The alkyl group represented by R ² may be a cyclic alkyl group or a chain alkyl group, but a chain alkyl group is preferable, and a linear alkyl group is more preferable than a branched chain alkyl group. preferable.

  The number of carbon atoms in the alkyl group is preferably 1-30, more preferably 1-20, further preferably 1-10, still more preferably 1-8, and 1-6. Most preferred. The alkyl group may have a substituent. Examples of the substituent include a halogen atom, an alkoxy group (for example, methoxy group, ethoxy group) and an acyloxy group (for example, acryloyloxy group, methacryloyloxy group).

The alkenyl group represented by R ² may be a cyclic alkenyl group or a chain alkenyl group, but preferably represents a chain alkenyl group, and is a straight chain alkenyl group rather than a branched chain alkenyl group. More preferably it represents a group. The number of carbon atoms in the alkenyl group is preferably 2 to 30, more preferably 2 to 20, still more preferably 2 to 10, still more preferably 2 to 8, 6 is most preferred. The alkenyl group may have a substituent. Examples of the substituent are the same as those of the alkyl group described above.

The aromatic ring group and heterocyclic group represented by R ² are the same as the aromatic ring and heterocyclic ring represented by R ¹ , and the preferred range is also the same. The aromatic ring group and the heterocyclic group may further have a substituent, and examples of the substituent are the same as those of the aromatic ring and heterocyclic ring of R ¹ .

  As the discotic compound, a triphenylene compound represented by the following general formula (5) can also be preferably used.

In the general formula (5), R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ each independently represent a hydrogen atom or a substituent.

The substituent represented by each of R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ is an alkyl group (preferably having 1 to 40 carbon atoms, more preferably 1 to 30 carbon atoms, and particularly preferably carbon number). 1-20 alkyl groups, such as methyl, ethyl, isopropyl, tert-butyl, n-octyl, n-decyl, n-hexadecyl, cyclopropyl, cyclopentyl, cyclohexyl, etc. ), An alkenyl group (preferably an alkenyl group having 2 to 40 carbon atoms, more preferably 2 to 30 carbon atoms, particularly preferably 2 to 20 carbon atoms, such as a vinyl group, an allyl group, 2- Butenyl group, 3-pentenyl group and the like), alkynyl group (preferably 2 to 40 carbon atoms, more preferably 2 to 30 carbon atoms, particularly preferably 2 carbon atoms). -20 alkynyl group, for example, propargyl group, 3-pentynyl group, etc., aryl group (preferably 6-30 carbon atoms, more preferably 6-20 carbon atoms, particularly preferably 6-6 carbon atoms). 12 aryl groups, for example, phenyl group, p-methylphenyl group, naphthyl group, etc., substituted or unsubstituted amino group (preferably having 0 to 40 carbon atoms, more preferably 0 to 30 carbon atoms). And particularly preferably an amino group having 0 to 20 carbon atoms, such as an unsubstituted amino group, a methylamino group, a dimethylamino group, a diethylamino group, and an anilino group), an alkoxy group (preferably having a carbon number of 1 to 40, more preferably an alkoxy group having 1 to 30 carbon atoms, particularly preferably 1 to 20 carbon atoms, such as a methoxy group, an ethoxy group, And the like, and an aryloxy group (preferably an aryloxy group having 6 to 40 carbon atoms, more preferably 6 to 30 carbon atoms, particularly preferably 6 to 20 carbon atoms, such as a phenyloxy group, 2-naphthyloxy group and the like), an acyl group (preferably 1 to 40 carbon atoms, more preferably 1 to 30 carbon atoms, particularly preferably an acyl group having 1 to 20 carbon atoms, for example, an acetyl group, A benzoyl group, a formyl group, a pivaloyl group, and the like), an alkoxycarbonyl group (preferably an alkoxycarbonyl group having 2 to 40 carbon atoms, more preferably 2 to 30 carbon atoms, particularly preferably 2 to 20 carbon atoms, For example, methoxycarbonyl group, ethoxycarbonyl group, etc.), aryloxycarbonyl group (preferably carbon An aryloxycarbonyl group having 7 to 40 carbon atoms, more preferably 7 to 30 carbon atoms, particularly preferably 7 to 20 carbon atoms, such as a phenyloxycarbonyl group, and an acyloxy group (preferably 2 to 2 carbon atoms). 40, more preferably an acyloxy group having 2 to 30 carbon atoms, particularly preferably 2 to 20 carbon atoms, such as an acetoxy group and a benzoyloxy group), an acylamino group (preferably having 2 to 40 carbon atoms, More preferably, it is an acylamino group having 2 to 30 carbon atoms, particularly preferably 2 to 20 carbon atoms, and examples thereof include an acetylamino group and a benzoylamino group), an alkoxycarbonylamino group (preferably having 2 to 40 carbon atoms, More preferred is an alkoxycarbonyl group having 2 to 30 carbon atoms, particularly preferably 2 to 20 carbon atoms. A mino group such as a methoxycarbonylamino group), an aryloxycarbonylamino group (preferably having 7 to 40 carbon atoms, more preferably 7 to 30 carbon atoms, particularly preferably 7 to 20 carbon atoms). An oxycarbonylamino group such as a phenyloxycarbonylamino group), a sulfonylamino group (preferably having 1 to 40 carbon atoms, more preferably 1 to 30 carbon atoms, and particularly preferably 1 to 20 carbon atoms). A sulfonylamino group, for example, a methanesulfonylamino group, a benzenesulfonylamino group, and the like; a sulfamoyl group (preferably having 0 to 40 carbon atoms, more preferably 0 to 30 carbon atoms, and particularly preferably 0 to 0 carbon atoms). 20 sulfamoyl groups such as sulfamoyl group, methylsulfur group A moyl group, a dimethylsulfamoyl group, a phenylsulfamoyl group and the like), a carbamoyl group (preferably having 1 to 40 carbon atoms, more preferably 1 to 30 carbon atoms, and particularly preferably 1 to 20 carbon atoms). A non-substituted carbamoyl group, a methylcarbamoyl group, a diethylcarbamoyl group, a phenylcarbamoyl group, etc., an alkylthio group (preferably having 1 to 40 carbon atoms, more preferably 1 to 30 carbon atoms, especially Preferably it is C1-C20, for example, a methylthio group, an ethylthio group, a propylthio group, a butylthio group, a pentylthio group, a hexylthio group, a heptylthio group, an octylthio group etc. are mentioned, An arylthio group (preferably 6 carbon atoms) ~ 40, more preferably 6-30 carbon atoms, especially preferred Is a sulfonyl group having 1 to 20 carbon atoms, such as a phenylthio group, preferably a sulfonyl group (preferably having 1 to 40 carbon atoms, more preferably 1 to 30 carbon atoms, and particularly preferably 1 to 20 carbon atoms). , For example, a mesyl group, a tosyl group, etc.), a sulfinyl group (preferably a sulfinyl group having 1 to 40 carbon atoms, more preferably 1 to 30 carbon atoms, particularly preferably 1 to 20 carbon atoms, A methanesulfinyl group, a benzenesulfinyl group and the like), a ureido group (preferably a ureido group having 1 to 40 carbon atoms, more preferably 1 to 30 carbon atoms, and particularly preferably 1 to 20 carbon atoms). Substituted ureido group, methylureido group, phenylureido group, etc.), phosphoric acid amide group (preferably having 1 to 40 carbon atoms) More preferably, it is a phosphoric acid amide group having 1 to 30 carbon atoms, particularly preferably 1 to 20 carbon atoms, and examples thereof include a diethylphosphoric acid amide group and a phenylphosphoric acid amide group), a hydroxy group, a mercapto group, Halogen atom (for example, fluorine atom, chlorine atom, bromine atom, iodine atom), cyano group, sulfo group, carboxy group, nitro group, hydroxamic acid group, sulfino group, hydrazino group, imino group, heterocyclic group (preferably carbon number) 1-30, more preferably 1-12, for example, a heterocyclic group having a heteroatom such as a nitrogen atom, oxygen atom, sulfur atom, etc., for example, an imidazolyl group, a pyridyl group, a quinolyl group, Furyl group, piperidyl group, morpholino group, benzoxazolyl group, benzimidazolyl group, benzthiazolyl group, 1,3,5- A silyl group (preferably 3 to 40 carbon atoms, more preferably 3 to 30 carbon atoms, and particularly preferably 3 to 24 carbon atoms). A phenylsilyl group, etc.). These substituents may be further substituted with these substituents. Moreover, when it has two or more substituents, they may be the same or different. If possible, they may be bonded to each other to form a ring.

The substituents represented by R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ are each preferably an alkyl group, an aryl group, a substituted or unsubstituted amino group, an alkoxy group, an alkylthio group or a halogen atom. is there.

  Hereinafter, although the specific example of a compound represented by General formula (5) is given, it is not limited to this.

  The compound represented by the general formula (4) is, for example, a method described in JP-A-2003-344655, and the compound represented by the general formula (5) is, for example, described in JP-A-2005-134484. It can synthesize | combine by well-known methods, such as a method.

  In the present invention, in addition to the aforementioned discotic compound, a rod-shaped compound having a linear molecular structure can also be preferably used. The linear molecular structure means that the molecular structure of the rod-like compound is linear in the most thermodynamically stable structure. The most thermodynamically stable structure can be obtained by crystal structure analysis or molecular orbital calculation. For example, molecular orbital calculation is performed using molecular orbital calculation software (for example, WinMOPAC2000, manufactured by Fujitsu Limited), and a molecular structure that minimizes the heat of formation of a compound can be obtained. The molecular structure being linear means that in the thermodynamically most stable structure obtained by calculation as described above, the angle of the main chain constituting the molecular structure is 140 degrees or more.

  As the rod-shaped compound having at least two aromatic rings, a compound represented by the following general formula (6) is preferable.

General formula (6)
Ar ₁ -L ₁ -Ar ₂
In the general formula (6), Ar ₁ and Ar ₂ are each independently an aromatic group. Here, the aromatic group includes an aryl group (aromatic hydrocarbon group), a substituted aryl group, an aromatic heterocyclic group, and a substituted aromatic heterocyclic group.

  An aryl group and a substituted aryl group are more preferable than an aromatic heterocyclic group and a substituted aromatic heterocyclic group. The heterocyclic ring of the aromatic heterocyclic group is generally unsaturated. The aromatic heterocycle is preferably a 5-membered ring, 6-membered ring or 7-membered ring, more preferably a 5-membered ring or 6-membered ring. Aromatic heterocycles generally have the most double bonds. As a hetero atom, a nitrogen atom, an oxygen atom or a sulfur atom is preferable, and a nitrogen atom or a sulfur atom is more preferable.

  As the aromatic ring of the aromatic group, a benzene ring, a furan ring, a thiophene ring, a pyrrole ring, an oxazole ring, a thiazole ring, an imidazole ring, a triazole ring, a pyridine ring, a pyrimidine ring and a pyrazine ring are preferable, and a benzene ring is particularly preferable. .

  Examples of the substituent of the substituted aryl group and the substituted aromatic heterocyclic group include a halogen atom (F, Cl, Br, I), a hydroxy group, a carboxy group, a cyano group, an amino group, an alkylamino group (for example, methyl Amino group, ethylamino group, butylamino group, dimethylamino group), nitro group, sulfo group, carbamoyl group, alkylcarbamoyl group (for example, N-methylcarbamoyl group, N-ethylcarbamoyl group, N, N-) Dimethylcarbamoyl group), sulfamoyl group, alkylsulfamoyl group (eg, N-methylsulfamoyl group, N-ethylsulfamoyl group, N, N-dimethylsulfamoyl group), ureido Group, alkylureido group (for example, N-methylureido group, N, N-dimethylureido group, N, N, N′-trimethyl) Each group of raid group), alkyl group (for example, methyl group, ethyl group, propyl group, butyl group, pentyl group, heptyl group, octyl group, isopropyl group, s-butyl group, tert-amyl group, cyclohexyl group, cyclopentyl) Group), alkenyl group (for example, vinyl group, allyl group, hexenyl group), alkynyl group (for example, ethynyl group, butynyl group), acyl group (for example, formyl group, acetyl group, butyryl group, Hexanoyl group, lauryl group), acyloxy group (for example, acetoxy group, butyryloxy group, hexanoyloxy group, lauryloxy group), alkoxy group (for example, methoxy group, ethoxy group, propoxy group, butoxy group) , Pentyloxy group, heptyloxy group, octyloxy group), aryloxy (For example, phenoxy group), alkoxycarbonyl group (for example, methoxycarbonyl group, ethoxycarbonyl group, propoxycarbonyl group, butoxycarbonyl group, pentyloxycarbonyl group, heptyloxycarbonyl group), aryloxycarbonyl group (for example, Phenoxycarbonyl group), alkoxycarbonylamino group (for example, butoxycarbonylamino group, hexyloxycarbonylamino group), alkylthio group (for example, methylthio group, ethylthio group, propylthio group, butylthio group, pentylthio group, heptylthio group, octylthio group) Each group), arylthio group (for example, phenylthio group), alkylsulfonyl group (for example, methylsulfonyl group, ethylsulfonyl group, propylsulfonyl group, butylsulfonyl group) , Pentylsulfonyl group, heptylsulfonyl group, octylsulfonyl group), amide group (for example, acetamido group, butyramide group, hexylamide group, laurylamide group) and non-aromatic heterocyclic group (for example, Morpholyl group, pyrazinyl group).

  Among these, preferable substituents include halogen atoms, cyano groups, carboxy groups, hydroxy groups, amino groups, alkylamino groups, acyl groups, acyloxy groups, amide groups, alkoxycarbonyl groups, alkoxy groups, alkylthio groups, and alkyl groups. Can be mentioned.

  The alkyl moiety of the alkylamino group, alkoxycarbonyl group, alkoxy group, and alkylthio group and the alkyl group may further have a substituent. Examples of the alkyl moiety and the substituent of the alkyl group include a halogen atom, hydroxy group, carboxy group, cyano group, amino group, alkylamino group, nitro group, sulfo group, carbamoyl group, alkylcarbamoyl group, sulfamoyl group, alkylsulfur group. Famoyl group, ureido group, alkylureido group, alkenyl group, alkynyl group, acyl group, acyloxy group, alkoxy group, aryloxy group, alkoxycarbonyl group, aryloxycarbonyl group, alkoxycarbonylamino group, alkylthio group, arylthio group, An alkylsulfonyl group, an amide group and a non-aromatic heterocyclic group are included. As the substituent for the alkyl moiety and the alkyl group, a halogen atom, a hydroxy group, an amino group, an alkylamino group, an acyl group, an acyloxy group, an acylamino group, an alkoxycarbonyl group, and an alkoxy group are preferable.

In General Formula (6), L ₁ is a divalent linking group selected from an alkylene group, an alkenylene group, an alkynylene group, —O—, —CO—, and a combination thereof.

  The alkylene group may have a cyclic structure. As the cyclic alkylene group, cyclohexylene is preferable, and 1,4-cyclohexylene is particularly preferable. As the chain alkylene group, a linear alkylene group is more preferable than a branched alkylene group.

  The number of carbon atoms of the alkylene group is preferably 1-20, more preferably 1-15, still more preferably 1-10, still more preferably 1-8, and most preferably 1-6. It is.

  The alkenylene group and the alkynylene group preferably have a chain structure rather than a cyclic structure, and more preferably have a linear structure rather than a branched chain structure.

  The alkenylene group and the alkynylene group preferably have 2 to 10 carbon atoms, more preferably 2 to 8, more preferably 2 to 6, still more preferably 2 to 4, and most preferably 2. (Vinylene group or ethynylene group).

  The arylene group preferably has 6 to 20 carbon atoms, more preferably 6 to 16, and still more preferably 6 to 12.

In the molecular structure of the general formula (6), the angle formed by Ar ₁ and Ar ₂ across L ₁ is preferably 140 ° or more.

  As the rod-like compound, a compound represented by the following general formula (7) is more preferable.

General formula (7)
Ar ₁ -L ₂ -XL ₃ -Ar ₂
In the general formula (7), Ar ₁ and Ar ₂ are each independently an aromatic group. The definition and examples of the aromatic group are the same as those of Ar ₁ and Ar _{2 in} the general formula (6).

In General Formula (7), L ₂ and L ₃ are each independently a divalent linking group selected from an alkylene group, —O—, —CO—, and a group consisting of a combination thereof.

  The alkylene group preferably has a chain structure rather than a cyclic structure, and more preferably has a linear structure rather than a branched chain structure.

  The alkylene group preferably has 1 to 10 carbon atoms, more preferably 1 to 8, more preferably 1 to 6, still more preferably 1 to 4, and 1 or 2 (methylene group). Or ethylene group).

L ₂ and L ₃ are particularly preferably —O—CO— or CO—O—.

  In General formula (7), X is a 1, 4- cyclohexylene group, vinylene group, or an ethynylene group.

Specific examples of the compound represented by the general formula (6) or (7) include JP-A-2004-109.
And the compounds described in [Chemical Formula 1] to [Chemical Formula 11] of No. 657.

  Two or more rod-shaped compounds whose maximum absorption wavelength (λmax) is longer than 250 nm in the ultraviolet absorption spectrum of the solution may be used in combination.

  The rod-like compound can be synthesized with reference to methods described in literature. As literature, Mol. Cryst. Liq. Cryst. 53, 229 (1979), 89, 93 (1982), 145, 111 (1987), 170, 43 (1989), J. Am. Am. Chem. Soc. 113, p. 1349 (1991), p. 118, p. 5346 (1996), p. 92, p. 1582 (1970). Org. Chem. 40, 420 pages (1975), Tetrahedron, Vol. 48, No. 16, page 3437 (1992).

  Moreover, you may use the rod-shaped aromatic compound of the 11-11 pages of Unexamined-Japanese-Patent No. 2004-50516 as said retardation (retardation) developing agent.

  When the optical film is produced by a solvent cast method, the retardation developing agent may be added to the dope. The addition may be performed at any timing. For example, a retardation developing agent may be dissolved in an organic solvent such as alcohol, methylene chloride, dioxolane, etc., and then added to the cellulose ester solution (dope). Or may be added directly into the dope composition.

  In addition, specific examples of preferable compounds of rod-like compounds other than those described in the above-mentioned publications are shown below.

  The specific examples (1) to (34), (41), and (42) have two asymmetric carbon atoms at the 1-position and the 4-position of the cyclohexane ring. However, since the specific examples (1), (4) to (34), (41), and (42) have a symmetrical meso type molecular structure, there are no optical isomers (optical activity), and geometric isomers (trans Type and cis type). The trans type (1-trans) and cis type (1-cis) of specific example (1) are shown below.

  As described above, the rod-like compound preferably has a linear molecular structure. Therefore, the trans type is preferable to the cis type.

  Specific examples (2) and (3) have optical isomers (a total of four isomers) in addition to geometric isomers. As for geometric isomers, the trans type is similarly preferable to the cis type. The optical isomer is not particularly superior or inferior, and may be D, L, or a racemate.

  In specific examples (43) to (45), the central vinylene bond includes a trans type and a cis type. For the same reason as above, the trans type is preferable to the cis type.

<Other additives for the first protective film>
In the cellulose ester film preferably used for the first protective film, as other additives that can be added to the ordinary cellulose ester film, various additives used in the production of the thermoplastic resin according to the polarizer, The same can be applied.

(Thermoplastic resin layer (second protective film) and first protective film manufacturing method)
Next, about the manufacturing method of the cellulose-ester film which preferably forms the thermoplastic resin layer used for preparation of a polarizer, the 2nd protective film (electrode side), and the 1st protective film (non-electrode side) based on this invention. explain.

  The cellulose ester film is preferably a cellulose ester film produced by a solution casting method or a melt casting method.

  The cellulose ester film is produced by dissolving a cellulose ester, a compound having negative orientation birefringence and an additive in a solvent to prepare a dope, and casting the dope on an endless metal support that moves infinitely. It is performed by a step of drying the cast dope as a web, a step of peeling from the metal support, a step of stretching or maintaining the width, a step of further drying, and a step of winding up the finished film.

  The process for preparing the dope will be described. The concentration of cellulose ester in the dope is preferably higher because the drying load after casting on the metal support can be reduced. However, if the concentration of cellulose ester is too high, the load during filtration increases and the filtration accuracy is poor. Become. As a density | concentration which makes these compatible, 10-35 mass% is preferable, More preferably, it is 15-25 mass%.

  The solvent used in the dope may be used alone or in combination of two or more, but it is preferable to use a mixture of a good solvent and a poor solvent of cellulose ester in terms of production efficiency, and there are many good solvents. This is preferable from the viewpoint of the solubility of the cellulose ester.

  The preferable range of the mixing ratio of the good solvent and the poor solvent is 70 to 98% by mass for the good solvent and 2 to 30% by mass for the poor solvent. With a good solvent and a poor solvent, what dissolve | melts the cellulose ester to be used independently is defined as a good solvent, and what poorly swells or does not melt | dissolve is defined as a poor solvent.

  Therefore, depending on the average acetylation degree (acetyl group substitution degree) of the cellulose ester, the good solvent and the poor solvent change. For example, when acetone is used as a solvent, the cellulose ester acetate (acetyl group substitution degree 2.4), Cellulose acetate propionate is a good solvent, and cellulose acetate (acetyl group substitution degree 2.8) is a poor solvent.

  Although the good solvent used for this invention is not specifically limited, Organic halogen compounds, such as a methylene chloride, dioxolanes, acetone, methyl acetate, methyl acetoacetate, etc. are mentioned. Particularly preferred is methylene chloride or methyl acetate.

  Moreover, although the poor solvent used for this invention is not specifically limited, For example, methanol, ethanol, n-butanol, cyclohexane, cyclohexanone, etc. are used preferably. Moreover, it is preferable that 0.01-2 mass% of water contains in dope. Moreover, the solvent used for melt | dissolution of a cellulose ester collect | recovers the solvent removed from the film by drying at the film-forming process, and uses this again.

  A general method can be used as a dissolution method of the cellulose ester when preparing the dope described above. When heating and pressurization are combined, it can be heated above the boiling point at normal pressure. It is preferable to stir and dissolve while heating at a temperature that is equal to or higher than the boiling point of the solvent at normal pressure and that the solvent does not boil under pressure, in order to prevent the generation of massive undissolved materials called gels and mamacos. Moreover, after mixing a cellulose ester with a poor solvent and making it wet or swell, the method of adding a good solvent and melt | dissolving is also used preferably.

  The pressurization may be performed by a method of injecting an inert gas such as nitrogen gas or a method of increasing the vapor pressure of the solvent by heating. Heating is preferably performed from the outside. For example, a jacket type is preferable because temperature control is easy.

  The heating temperature with the addition of a solvent is preferably higher from the viewpoint of the solubility of the cellulose ester, but if the heating temperature is too high, the required pressure increases and the productivity deteriorates. A preferable heating temperature is 45 to 120 ° C, more preferably 60 to 110 ° C, and still more preferably 70 ° C to 105 ° C. The pressure is adjusted so that the solvent does not boil at the set temperature.

  Alternatively, a cooling dissolution method is also preferably used, whereby the cellulose ester can be dissolved in a solvent such as methyl acetate.

  Next, this cellulose ester solution is filtered using a suitable filter medium such as filter paper. As the filter medium, it is preferable that the absolute filtration accuracy is small in order to remove insoluble matters and the like, but there is a problem that the filter medium is likely to be clogged if the absolute filtration accuracy is too small. Therefore, a filter medium with an absolute filtration accuracy of 0.008 mm or less is preferable, a filter medium with an absolute filtration accuracy within the range of 0.001 to 0.008 mm is more preferable, and an absolute filtration accuracy within the range of 0.003 to 0.006 mm. A filter medium is more preferable.

  There are no particular restrictions on the material of the filter medium, and ordinary filter media can be used. However, plastic filter media such as polypropylene and Teflon (registered trademark), and metal filter media such as stainless steel do not drop off fibers. preferable. It is preferable to remove and reduce impurities, particularly bright spot foreign matter, contained in the raw material cellulose ester by filtration.

The bright spot foreign matter was placed in a crossed Nicols state with two polarizing plates, a rolled cellulose ester was placed between them, and light was applied from the side of one polarizing plate, and observed from the side of the other polarizing plate. It is a point (foreign matter) where light from the opposite side sometimes leaks, and the number of bright spots having a diameter of 0.01 mm or more is preferably 200 / cm ² or less. More preferably, it is 100 pieces / cm < ² > or less, More preferably, it is 50 pieces / m < ² > or less, More preferably, it is 0-10 pieces / cm < ² > or less. Further, it is preferable that the number of bright spots of 0.01 mm or less is small.

  The dope can be filtered by a normal method, but the method of filtering while heating at a temperature not lower than the boiling point of the solvent at normal pressure and in a range where the solvent does not boil under pressure is the filtration pressure before and after filtration. The increase in the difference (referred to as differential pressure) is small and preferable. A preferable temperature is 45 to 120 ° C, more preferably 45 to 70 ° C, and still more preferably within a range of 45 to 55 ° C.

  A smaller filtration pressure is preferred. The filtration pressure is preferably 1.6 MPa or less, more preferably 1.2 MPa or less, and further preferably 1.0 MPa or less.

  Here, the dope casting will be described.

  The metal support in the casting (casting) step preferably has a mirror-finished surface, and a stainless steel belt or a drum whose surface is plated with a casting is preferably used as the metal support. The cast width can be 1 to 4 m. The surface temperature of the metal support in the casting step is −50 ° C. to less than the boiling point of the solvent, and a higher temperature is preferable because the web drying speed can be increased. However, if the temperature is too high, the web foams and is flat. May deteriorate. The support temperature is preferably in the range of 0 to 40 ° C, more preferably in the range of 5 to 30 ° C.

  Alternatively, it is also a preferable method that the web is gelled by cooling and peeled from the drum in a state containing a large amount of residual solvent.

  The method for controlling the temperature of the metal support is not particularly limited, and there are a method of blowing hot air or cold air, and a method of contacting hot water with the back side of the metal support. It is preferable to use warm water because heat transfer is performed efficiently, so that the time until the temperature of the metal support becomes constant is short. When warm air is used, wind at a temperature higher than the target temperature may be used.

  In order for the roll cellulose ester to exhibit good flatness, the residual solvent amount when peeling the web from the metal support is preferably 10 to 150% by mass, more preferably 20 to 40% by mass or 60 to 130% by mass. %, Particularly preferably in the range of 20-30% by mass or 70-120% by mass.

  In the present invention, the amount of residual solvent is defined by the following formula.

Residual solvent amount (% by mass) = {(MN) / N} × 100
M is the mass of a sample collected during or after the production of the web or film, and N is the mass after heating M at 115 ° C. for 1 hour.

  In the drying step of the roll cellulose ester, the web is peeled off from the metal support and further dried, and the residual solvent amount is preferably 1% by mass or less, more preferably 0.1% by mass or less. Especially preferably, it exists in the range of 0-0.01 mass%.

  In the film drying process, generally, a roll drying method (a method in which a plurality of rolls arranged on the upper and lower sides are alternately passed through and dried) or a method of drying while conveying the web by a tenter method is adopted.

  In order to produce a cellulose ester film, a tenter method in which the web is stretched in the transport direction (= long direction) where the residual solvent amount of the web immediately after peeling from the metal support is large, and further, both ends of the web are gripped with clips or the like. It is particularly preferable to perform stretching in the width direction.

  Further, in the production of the first protective film, before or after stretching, the functions of an antistatic layer, a backcoat layer, a slippery layer, an adhesive layer, a barrier layer, an antiglare layer, an antireflection layer, an optical compensation layer, etc. A layer may be applied.

[Second protective film]
The circularly-polarizing plate which concerns on this invention may provide a 2nd protective film on the opposite side through the said 1st protective film and a polarizer as needed. There is no restriction | limiting in particular as a 2nd protective film, A commercially available cellulose-ester film can be used. As a commercially available cellulose ester film, for example, Konica Minoltack KC8UX, KC5UX, KC8UCR3, KC8UCR4, KC8UCR5, KC8UY, KC4UA, KC4UY, KC4UE, KC8UE-KC8UY-HA, KC8UX-H8, -NC, KC4UXW-RHA-NC (above, manufactured by Konica Minolta Opto Co., Ltd.) and the like are preferably used. Moreover, the thermoplastic resin film used for preparation of the polarizer which concerns on this invention demonstrated above can also be used. Alternatively, it is also preferable to use a protective film that also serves as an optical compensation film having an optically anisotropic layer formed by aligning liquid crystal compounds such as discotic liquid crystal, rod-shaped liquid crystal, and cholesteric liquid crystal. For example, the optically anisotropic layer can be formed by the method described in JP-A-2003-98348. By using in combination with the polarizing plate according to the present invention, a polarizing plate having excellent flatness and a stable viewing angle expansion effect can be obtained. In addition, as a polarizing plate protective film located in the side far from a liquid crystal cell, or on the said film, it is also possible to arrange | position the film which has other functionality, when improving the quality of a display apparatus. For example, anti-reflection (anti-reflection (AR)), anti-glare (anti-glare (AG)), scratch resistance (hard coat (HC)), low reflection (low reflection (LR)), dust adhesion prevention, brightness improvement, anti-static A film containing a known functional layer as a display for antifouling and back coating can be used as a polarizing plate protective film. Or you may affix separately the film containing these functional layers on the surface of polarizing plate protective films, such as a general purpose TAC film.

  When using the circularly-polarizing plate of this invention for an IPS type | mold liquid crystal display device, a 2nd protective film is arrange | positioned between the liquid crystal cell and polarizer of the electrode side. In the second protective film, the in-plane direction retardation Ro is preferably 0 nm ≦ Ro ≦ 5 nm, and the thickness direction retardation Rt is preferably −5 nm ≦ Rt ≦ 5 nm. The means for setting Ro and Rt to the desired values is not limited as long as the film is a single sheet, but is preferably a cellulose ester containing a compound having negative orientation birefringence and having a film thickness of 20 It is preferable to be within a range of ˜60 μm.

  Moreover, as a film thickness of a 2nd protective film, it is preferable to exist in the range of 20-60 micrometers.

<Display device>
The circularly polarizing plate according to the present invention can be applied to various display devices such as a liquid crystal display device and an organic electroluminescence (EL) display device.

  For example, by incorporating the circularly polarizing plate according to the present invention into a liquid crystal display device, various liquid crystal display devices with excellent visibility can be manufactured. In addition, since the circularly polarizing plate according to the present invention has excellent reworkability, the productivity of the display device can be greatly improved. Note that the circularly polarizing plate according to the present invention can be used for liquid crystal display devices of various drive systems such as STN, TN, OCB, HAN, VA (MVA, PVA), and IPS. Preferably, VA (MVA, PVA) type and IPS type liquid crystal display devices are used. In particular, it is preferably incorporated in an IPS mode liquid crystal display device.

  The liquid crystal layer of the liquid crystal panel in the IPS mode type liquid crystal display device is homogeneously aligned parallel to the substrate surface in the initial state, and the director of the liquid crystal layer is parallel to the electrode wiring direction when no voltage is applied. The direction of the director of the liquid crystal layer shifts to a direction perpendicular to the electrode wiring direction when a voltage is applied, and the director direction of the liquid crystal layer is the direction of the director when no voltage is applied. When tilted in the direction of the electrode wiring by 45 ° compared to the liquid crystal layer when the voltage is applied, the azimuth angle of the polarization is rotated by 90 ° like a half-wave plate, and the transmission axis and polarization of the output side polarizing plate are rotated. The azimuth angles of the two coincide with each other to display white.

  In general, the thickness of the liquid crystal layer is constant, but since it is driven by a lateral electric field, it may be possible to increase the response speed to switching by providing a slight unevenness in the thickness of the liquid crystal layer. Even when the thickness is not constant, the effect can be utilized to the maximum, and the influence on the change in the thickness of the liquid crystal layer is small. The thickness of the liquid crystal layer is 2 to 6 μm, and preferably 3 to 5.5 μm. The liquid crystal display device according to this embodiment can be preferably used for portable devices such as a tablet display device and a smartphone in addition to being used for a large liquid crystal television.

  In addition, there is no restriction | limiting in particular about the detail of an IPS mode type liquid crystal cell, and this invention can be implemented by referring description of other conventionally well-known technical matters, for example, Unexamined-Japanese-Patent No. 2010-3060. .

  The details of the organic electroluminescence (EL) display device are not particularly limited, and other conventionally known technical matters such as JP2010-243769, JP2011-8210, and 2010-212184 are known. The present invention can be implemented by referring to the description of the publication.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. In addition, although the display of "%" is used in an Example, unless otherwise indicated, "mass%" is represented.

Example 1
<Production of circularly polarizing plate>
[Production of Circular Polarizing Plate 101]
(Preparation of polarizer 1)
A 75 μm-thick polyvinyl alcohol film (manufactured by Kuraray Co., Ltd., vinylon film VF-P # 7500) is uniaxially stretched in the dry direction in the transport direction (MD direction) at a draw ratio of 5.2 times, and while maintaining a tension state, Each 100 parts by mass was immersed in an aqueous solution containing 0.05 parts by mass of iodine and 5 parts by mass of potassium iodide at a temperature of 28 ° C. for 60 seconds. Next, in a state where the tensioned state was maintained, it was immersed in a boric acid aqueous solution containing 7.5 parts by mass of boric acid and 6 parts by mass of potassium iodide per 100 parts by mass of water at a temperature of 73 ° C. for 300 seconds, and then Washed with pure water at 15 ° C. for 10 seconds.

  The film washed with water was dried with warm air at 70 ° C. for 300 seconds while maintaining the tension state, and the edge was cut off to obtain a polarizer 1 having a width of 1300 mm. The film thickness of this polarizer 1 (polarizing film single film) was 33 μm.

(Preparation of the first protective film 1)
<Preparation of fine particle dispersion 1>
Fine particles (Aerosil R972V manufactured by Nippon Aerosil Co., Ltd.) 11 parts by weight Ethanol 89 parts by weight The above was stirred and mixed with a dissolver for 50 minutes, and then dispersed using a Manton Gorin disperser to prepare a fine particle dispersion 1.

<Preparation of fine particle additive solution 1>
The fine particle dispersion 1 was slowly added while sufficiently stirring the methylene chloride in the dissolution tank. Subsequently, it was dispersed using an attritor so that the particle size of the secondary particles became a predetermined size. Next, the mixture was filtered with Finemet NF manufactured by Nippon Seisen Co., Ltd. to prepare a fine particle additive solution 1.

Methylene chloride 99 parts by mass Fine particle dispersion 1 5 parts by mass <Preparation of main dope 1>
A main dope 1 having the following composition was prepared. First, methylene chloride and ethanol were added as solvents to the pressure dissolution tank. Cellulose acetate was added to the pressurized dissolution tank containing each solvent while stirring. This was heated and stirred to dissolve completely, and this was dissolved in Azumi Filter Paper No. The main dope 1 was prepared by filtration using 244.

<Composition of main dope 1>
Methylene chloride 340 parts by mass Ethanol 64 parts by mass Cellulose acetate with an acetyl group substitution degree of 2.45 (Mn; 53000)
100 parts by mass Sugar ester compound 1 10.0 parts by mass Ester compound 1 2.5 parts by mass UV absorber (Tinuvin 928 (manufactured by BASF Japan Ltd.)) 2.3 parts by mass Fine particle additive 1 1.0 part by mass

<Formation of the first protective film 1>
Each of the above additives was put into a sealed container and dissolved while stirring to prepare the main dope 1. Next, using the endless belt casting apparatus, the main dope 1 was uniformly cast on a stainless steel belt support at a temperature of 33 ° C. and a width of 2000 mm. The temperature of the stainless steel belt was controlled at 30 ° C.

  On the stainless steel belt support, the solvent was evaporated until the residual solvent amount in the cast (cast) film was 75%, and then peeled off from the stainless steel belt support with a peeling tension of 130 N / m.

  After peeling, using the apparatus described in Example 1 of JP-A-2009-214441 (stretching machine A: FIG. 11), the slow axis is 45 ° with the film width direction at a temperature of 170 ° C. and a magnification of 1.35 times. As was done, the film was stretched in an oblique direction.

  Next, drying was completed while the drying zone was conveyed by a number of rollers. The drying temperature was 130 ° C. and the transport tension was 100 N / m.

  As described above, the first protective film having a dry film thickness of 80 μm, a stretching direction θ = 45 °, Ro = 138 nm, and Rt = 160 nm, having a knurling of 1300 mm in width and 1 cm in width at the end and 8 μm in height. 1 (λ / 4 film) was obtained.

(Production of circularly polarizing plate)
Next, the polarizer 1 and the first protective film 1 produced in accordance with the following steps 1 to 5 were bonded together to produce a circularly polarizing plate 1.

  Step 1: The first protection film 1 is immersed in a 2 mol / L sodium hydroxide solution at 60 ° C. for 90 seconds, then washed with water and dried to saponify the side to be bonded to the polarizer. Film 1 was obtained.

  Step 2: A polyvinyl alcohol adhesive having a solid content of 2% by mass was applied to one side of the polarizer 1.

  Step 3: The first protective film 1 treated in Step 1 was placed on the surface of the polarizer coated with the polyvinyl alcohol adhesive in Step 2.

Step 4: The first protective film 1 and the polarizer 1 laminated in Step 3 were bonded at a pressure of 20 to 30 N / cm ² and a conveyance speed of about 2 m / min.

  Step 5: The sample produced in Step 4 was dried for 2 minutes in a dryer at 80 ° C. to produce a roll-shaped circularly polarizing plate 101.

  In the obtained circularly polarizing plate 101, the angle formed by the slow axis of the first protective film 1 and the absorption axis of the polarizer was 45 °.

[Production of Circular Polarizing Plate 102]
(Preparation of polarizer 2)
In the production method of the polarizer 1 used for the production of the circularly polarizing plate 101, the apparatus described in Example 1 of JP-A-2009-214441 (stretching machine A: FIG. 11) was used, and the stretching temperature was 55 ° C. A polarizer 2 made of a polyvinyl alcohol film was produced in the same manner except that the film was stretched in an oblique direction so that the absorption axis was 45 ° with the film width direction at a magnification of 5.7. The thickness of the polarizer 2 was 37 μm.

(Preparation of the first protective film 2)
In the manufacturing method of the 1st protective film 1 used for preparation of the said circularly-polarizing plate 101, a solvent is evaporated until the amount of residual solvents in the cast (cast) film becomes 75% on a stainless steel belt support body. Then, after peeling from the stainless steel belt support with a peeling tension of 130 N / m, both ends of the web are gripped by a tenter and stretched so that the stretching ratio in the width (TD) direction is 1.35 times. This is the same except that the width is maintained for several seconds while the width is maintained, the tension in the width direction is relaxed, the width is released, and further, transported for 30 minutes in the third drying zone set at 125 ° C. for drying. Thus, a first protective film 2 (λ / 4 film) was produced. The residual solvent at the start of stretching was 30%.

  The first protective film 2 produced as described above had a dry film thickness of 66 μm, a stretching direction θ = 90 °, Ro = 136 nm, and Rt = 228 nm.

(Production of circularly polarizing plate)
Subsequently, the polarizer 2 and the protective film 2 were bonded together according to the steps 1 to 5 used for the production of the circularly polarizing plate 101 to produce the circularly polarizing plate 102.

  In the obtained polarizing plate 102, the angle formed by the slow axis of the protective film 2 and the absorption axis of the polarizer was 45 °.

[Production of Circular Polarizing Plate 103]
(Preparation of stretched laminated film 1 having polarizing properties)
The surface of the 120 μm-thick amorphous polyethylene terephthalate sheet subjected to antistatic treatment was subjected to corona treatment, and this was used as a base film 1 (thermoplastic resin layer, abbreviated as PET in Table 1).

  On the base film 1, polyvinyl alcohol powder (manufactured by Nippon Vinegar Bipovar Co., Ltd., average polymerization degree 2500, saponification degree 99.0 mol% or more, trade name: JC-25) is 95 ° C. as a hydrophilic polymer. A polyvinyl alcohol aqueous solution having a concentration of 8% by mass was prepared by dissolving in hot water. The obtained aqueous polyvinyl alcohol solution was applied onto the base film 1 using a lip coater, dried at 80 ° C. for 20 minutes, and a laminate comprising the base film 1 (thermoplastic resin layer) and a hydrophilic polymer layer. A film (laminate) was produced. The hydrophilic polymer layer had a thickness of 12.0 μm.

<Extension process>
The laminated film was subjected to free end uniaxial stretching 5.3 times at 160 ° C. with respect to the transport direction (MD direction) to obtain a stretched laminated film (stretched laminate). The thickness of the hydrophilic resin layer after stretching was 5.6 μm.

<Dyeing process>
Thereafter, the stretched laminated film was immersed in warm water at 60 ° C. for 60 seconds, and then added to an aqueous solution containing 0.05 part by mass of iodine and 5 parts by mass of potassium iodide per 100 parts by mass of water at a temperature of 28 ° C. for 60 seconds. Soaked. Next, while maintaining the tension state, it was immersed in a boric acid aqueous solution containing 7.5 parts by mass of boric acid and 6 parts by mass of potassium iodide per 100 parts by mass of water at a temperature of 73 ° C. for 300 seconds. Then, it wash | cleaned for 10 second with 15 degreeC pure water. The stretched laminated film washed with water was dried at 70 ° C. for 300 seconds while keeping the tensioned state to obtain a stretched laminated film 1 having polarizing properties.

(Production of circularly polarizing plate)
After laminating the stretched laminated film 1 having polarization according to the following steps 1 to 6 and the first protective film 1 produced as described above, the base film 1 (thermoplastic resin layer) constituting the stretched laminated film 1 ) Was peeled off to produce a circularly polarizing plate 103.

  Step 1: The first protective film 1 is immersed in a 2 mol / L sodium hydroxide solution at 60 ° C. for 90 seconds, then washed with water and dried to saponify the side to be bonded to the polarizer. 1 was obtained.

  Process 2: The polyvinyl alcohol adhesive of 2 mass% of solid content was apply | coated to the polarizer surface side of the stretched laminated film 1 having the polarizing property.

  Process 3: The 1st protective film 1 processed at the process 1 was arrange | positioned on the surface which apply | coated the polyvinyl alcohol adhesive agent at the process 2. FIG.

Step 4: the first was laminated in Step 3 1 of the protective film 1 and the polarizer plane of the stretched laminated film 1, pressure 20-30 N / cm ^2, it was stuck at about 2m / min conveyor speed.

  Step 5: The sample produced in Step 4 was dried for 2 minutes in a dryer at 80 ° C. to obtain a circularly polarizing plate comprising a first protective film, a polarizer layer, and a substrate film.

  Process 6: The base film 1 (thermoplastic resin layer) constituting the stretched laminated film 1 was peeled from the obtained circularly polarizing plate. The base film 1 was easily peeled off to produce a roll-shaped circularly polarizing plate 103.

[Production of Polarizing Plate 104]
In the production of the stretched laminated film 1 having polarizing properties used for the production of the circularly polarizing plate 103, as stretching process conditions of the laminated film (laminated body), both ends of the web are gripped by a tenter, and the width (TD) direction is measured. A stretched laminated film 2 was produced in the same manner except that the stretch ratio was 5.5 times. The thickness of the hydrophilic polymer layer (polarizer) after stretching was 5.7 μm.

  Next, in the production of the circularly polarizing plate 103, a circularly polarizing plate 104 was produced in the same manner except that the produced stretched laminated film 2 was used instead of the stretched laminated film 1.

[Production of Circular Polarizing Plate 105]
In the production of the stretched laminated film 1 having polarizing properties used for the production of the circularly polarizing plate 103, as the stretching process conditions of the laminated film (laminate), the apparatus described in Example 1 of JP-A-2009-214441 ( Stretching machine A: FIG. 11) was used in the same manner except that stretching was performed in an oblique direction so that the stretching temperature was 160 ° C., the stretching ratio was 5.6 times, and the absorption axis was 45 ° with the film width direction. Film 3 was produced. The thickness of the hydrophilic polymer layer (polarizer) after stretching was 5.5 μm.

  Next, in the production of the circularly polarizing plate 103, a circularly polarizing plate 105 was produced in the same manner except that the produced stretched laminated film 3 was used instead of the stretched laminated film 1.

[Production of Circular Polarizing Plate 106]
In the production of the stretched laminated film 3 having polarizing properties used for the production of the circularly polarizing plate 105, as a stretching process condition of the laminated film (laminated body), a clip that stretches in an oblique direction and simultaneously grips both ends of the web A stretched laminated film 4 was produced in the same manner except that the interval was adjusted and a treatment for shrinking 45% in the direction perpendicular to the stretched direction was performed. The thickness of the hydrophilic polymer layer (polarizer) after stretching was 5.5 μm.

  Next, in the production of the circularly polarizing plate 105, the first laminated film 4 was used instead of the stretched laminated film 3, and the first protective film 1 was further used for producing the circularly polarizing plate 102. A circularly polarizing plate 106 was produced in the same manner except that the protective film 2 was changed.

[Production of Circular Polarizing Plate 107]
In the production of the circularly polarizing plate 105, a circularly polarizing plate 107 was produced in the same manner except that the first protective film 1 was changed to the following first protective film 3.

(Preparation of the first protective film 3)
A norbornene resin (Nippon ZEON Co., Ltd., ZEONOR (registered trademark) 1420, abbreviated as COP in Table 1) is melt-extruded at 250 ° C. and stretched in the width direction (TD direction) with a stretching machine. Thus, a first protective film 3 (λ / 4 film) having a dry film thickness of 58 μm, a stretching direction θ = 90 °, Ro = 138 nm, and Rt = 69 nm was obtained.

[Production of Circular Polarizing Plate 108]
In the production of the circularly polarizing plate 105, a circularly polarizing plate 108 was produced in the same manner except that the first protective film 1 was changed to the first protective film 4 described below.

(Preparation of the first protective film 4)
In the production of the first protective film 2, the solvent was evaporated on the stainless steel belt support until the residual solvent amount in the cast (cast) film became 75%, and then the stainless steel belt was peeled at a peeling tension of 130 N / m. After peeling from the belt support, it was stretched by 1.40 times in the longitudinal direction (MD direction; transport direction) at 155 ° C. by a stretching machine using a difference in roller peripheral speed. Next, it is introduced into a tenter having a preheating zone, a stretching zone, a holding zone, and a cooling zone (there is also a neutral zone for ensuring thermal insulation between the zones), and the width direction (TD direction; width) Direction) at 155 ° C. and then cooled to 30 ° C. while relaxing 2% in the width direction, then released from the clip, clipped off the clip gripping part, dried film thickness 60 μm, stretching direction θ A first protective film 4 (λ / 4 film) having = 0 °, Ro = 136 nm, and Rt = 228 nm was obtained.

[Production of Circular Polarizing Plate 109]
In the production of the circularly polarizing plate 105, the circularly polarizing plate 109 was produced in the same manner except that the stretched laminated film 1 was changed to the following stretched laminated film 5 and the stretching conditions were further changed as follows.

(Preparation of stretched laminated film 5 having polarization)
The following base film 2 was prepared as a base film (thermoplastic resin layer).

  The following constituent materials were further dried while being mixed at 80 ° C. and 133 Pa for 3 hours in a vacuum nauter mixer, and the resulting mixture was melt-mixed at 235 ° C. using a twin-screw extruder to be pelletized.

Acrylic resin (methyl methacrylate / acryloylmorpholine = 80/20 (molar ratio); Mw = 100000; dried at 90 ° C. for 3 hours and water content 1000 ppm) 70 parts by mass Cellulose ester resin (cellulose acetate propionate: total acyl group substitution) Degree 2.7, acetyl group substitution degree 0.1, propionyl group substitution degree 2.6, Mw = 200000, dried at 100 ° C. for 3 hours and water content 500 ppm) 30 parts by mass Tinuvin 928 (manufactured by BASF Japan Ltd.) 1 .1 part by weight ADK STAB PEP-36 (manufactured by ADEKA Corporation) 0.25 part by weight Irganox 1010 (manufactured by BASF Japan Ltd.) 0.5 part by weight Sumilizer GS (manufactured by Sumitomo Chemical Co., Ltd.) 0.24 parts by weight Aerosil R972V (manufactured by Nippon Aerosil Co., Ltd.) 0.27 parts by mass was obtained. Let were allowed to circulate over 5 hours 70 ° C. dehumidified air and dried by, while maintaining the temperature 100 ° C., and introduced into the next step uniaxial extruder.

  The pellets were melt extruded from a T die onto a first cooling roller having a surface temperature of 90 ° C. at a melting temperature of 240 ° C. using a single screw extruder to obtain a 120 μm cast film. Under the present circumstances, the film was pressed on the 1st cooling roller with the elastic touch roller which has a 2 mm-thick metal surface, and the base film 2 (thermoplastic resin layer) was produced.

  Next, 95 polyvinyl alcohol powder (manufactured by Nippon Vinegar Bipovar Co., Ltd., average polymerization degree 2500, saponification degree 99.0 mol% or more, trade name: JC-25) as a hydrophilic polymer on the base film 2 is 95. A polyvinyl alcohol aqueous solution having a concentration of 8% by mass was dissolved in hot water at 0 ° C. The obtained polyvinyl alcohol aqueous solution was applied onto the base film 2 using a lip coater, dried at 80 ° C. for 20 minutes, and a laminated film comprising the base film 2 and a hydrophilic polymer layer (polarizer) was obtained. Produced. The thickness of the hydrophilic polymer layer was 12.0 μm.

<Extension process>
In the production of the stretched laminated film 1, the laminated film was stretched at a temperature of 145 ° C. and a stretch ratio of 5.3 using the apparatus described in Example 1 of JP 2009-214441 A (stretching machine A: FIG. 11). A stretched laminated film 5 was produced in the same manner except that the film was stretched in an oblique direction so that the absorption axis was 45 ° with the film width direction. The thickness of the hydrophilic polymer layer (polarizer) after stretching was 5.2 μm.

  In addition, the detail of the item described in Table 1 with the abbreviation is as follows.

<Each material>
PVA: polyvinyl alcohol PET: polyethylene terephthalate TD: width direction MD: transport direction CE: cellulose ester COP: cycloolefin resin <Polarizer stretching method>
Stretching method 1A: Stretching the PVA single film in the MD direction Stretching method 2A: Stretching the PVA single film obliquely Stretching method 3A: Stretching the laminate in the MD direction Stretching method 4A: Stretching the laminate (PET) in the TD direction Stretching method 5A : Stretching the laminate (PET) by 45 ° obliquely Stretching method 6A: Stretching the laminate (PET) by 45 ° obliquely + shrinkage Stretching method 7A: Stretching the laminate (CE) by 45 ° obliquely <First Protective film stretching method>
Stretching method 1B: Stretching cellulose ester film diagonally Stretching method 2B: Stretching cellulose ester film in TD direction Stretching method 3B: Stretching cycloolefin film (COP) in TD direction Stretching method 4B: Stretching cellulose ester film in MD direction << Evaluation of Circular Polarizing Plate >>
Each roll-shaped circularly polarizing plate produced above was subjected to the following evaluations.

[Evaluation of curl]
The obtained roll-shaped circularly polarizing plate was drawn out, and a substantially central portion was cut out to have a size of 50 mm in the width direction and 30 mm in the longitudinal direction, and placed on a horizontal substrate for 24 hours in an environment of room temperature 23 ° C. and relative humidity 80%. After being allowed to stand, the curl shape of the circularly polarizing plate was visually observed, and the curl was evaluated according to the following criteria.

A: Almost flat, no occurrence of curl ○: Slightly raised at the four corners, weak curl is observed, but the quality has no problem in practice △: Clear curl is observed Curl characteristics that are difficult to handle ×: quality that makes the curl state tight and extremely difficult to handle (Durability 1 evaluation: resistance to uneven polarization degree after high-temperature and high-humidity treatment in a roll state)
After the produced roll-shaped circularly polarizing plate is left in a high-temperature and high-humidity environment at a room temperature of 60 ° C. and a relative humidity of 90% for one week, the circularly polarizing plate located at the outermost peripheral portion is widened from the end to the width direction. The degree of polarization C at the 25%, 50% and 75% positions of the full width was measured. Next, in the longitudinal direction, the same measurement is repeated every 10 m toward the core side, and the degree of polarization at a total of 150 points is measured for 500 m from the outside of the roll-shaped polarizing plate to the inside, and the degree of polarization at all measurement points varies. Was determined as the difference in percentage of polarization degree C (polarization degree 1).

  Similarly, for a roll-shaped circularly polarizing plate immediately after production which is not subjected to high temperature and high humidity, the same measurement is performed, and the variation in polarization degree at all measurement points is defined as the difference in percentage of polarization degree C (degree of polarization 2). Asked. Next, the degree of polarization 1 to the degree of polarization 2 is obtained, and this is set as the degree of increase in the degree of polarization variation (Δ polarization degree 1) in a high-temperature and high-humidity environment. As a scale, durability 1 was evaluated according to the following criteria.

  The degree of polarization C was measured using an automatic polarizing film measuring device VAP-7070 (manufactured by JASCO Corporation) and a dedicated program.

A: Δ polarization degree 1 is less than 1.0% B: Δ polarization degree 1 is 1.0% or more and less than 2.0% Δ: Δ polarization degree 1 is 2.0% or more, Less than 5.0% ×: Δ polarization degree 1 is 5.0% or more (Evaluation of durability 2: resistance to variation in polarization degree after high-temperature and high-humidity treatment in a glass-bonded state)
The roll-shaped circularly polarizing plate produced above is fed out and cut into a 42-inch liquid crystal panel size (930 mm x 520 mm) at approximately the center of 500 m from the outside of the roll and left for 24 hours in an atmosphere of 23 ° C and 55% relative humidity. did. Next, the cut circularly polarizing plate was placed on one side of a glass plate (thickness 1.2 mm) whose surface was previously washed with ethanol through a 25 μm double-sided adhesive tape (baseless tape MO-3005C manufactured by Lintec). Four sides were bonded so that the polarizer-forming surface of the polarizing plate faced the glass surface, and each glass plate bonded circularly polarizing plate was produced.

  Next, after this glass plate-bonded circularly polarizing plate was left in a high-temperature and high-humidity environment at a temperature of 60 ° C. and a relative humidity of 90% for 300 hours, the circularly polarizing plate was peeled off from the glass plate, and then the diagonal of the circularly polarizing plate was The polarization degree variation was measured as the difference in the percentage of the polarization degree C at the center point (ρ0) and the 75% point (ρ75) from the diagonal center. Next, a difference in each polarization degree variation (Δ polarization degree 2) is obtained, and this is used as a measure of polarization degree variation resistance after high-temperature and high-humidity treatment in a glass bonding state, and durability 2 is evaluated according to the following criteria. It was.

  The degree of polarization was measured using an automatic polarizing film measuring device VAP-7070 (manufactured by JASCO Corporation) and a dedicated program.

Difference in polarization degree variation (Δ polarization degree 2) = polarization degree variation (%) at 75% point (ρ75) −polarization degree variation (%) at the diagonal center point (ρ0) of the circularly polarizing plate
A: Δ polarization degree 2 is less than 1.0% B: Δ polarization degree 2 is 1.0% or more and less than 2.0% Δ: Δ polarization degree 2 is 2.0% or more, Less than 5.0% ×: Δ polarization degree 2 is 5.0% or more Table 2 shows the results obtained.

  As is apparent from the results shown in Table 2, the roll-shaped circularly polarizing plate having the configuration defined in the present invention can be made into a thin film polarizer with respect to the comparative example, and as a result, has excellent curl characteristics, And it turns out that it is excellent in the polarization degree nonuniformity tolerance at the time of storing in a high temperature, high humidity environment in a roll state, and the polarization degree variation tolerance at the time of storing in a high temperature, high humidity environment in a glass bonding state.

Example 2
<Production of liquid crystal display device>
Take out the liquid crystal panel from the liquid crystal display device “Regza 47ZG2 manufactured by Toshiba Corporation” including the liquid crystal cell of the horizontal electric field type switching mode type (IPS mode type), and remove the two sets of polarizing plates arranged above and below the liquid crystal cell. After removing, the glass surface (front and back) of the liquid crystal cell was washed.

  Subsequently, in each circularly polarizing plate produced in Example 1, the upper (viewing side) circularly polarizing plate is such that the polarizer is on the liquid crystal panel side, and the slow axis of the first protective film is the length of the liquid crystal cell. The liquid crystal so that it is parallel to the side (0 ± 0.2 degrees) and the lower (backlight side) circularly polarizing plate is parallel to the short side of the liquid crystal cell (0 ± 0.2 degrees). Attached to both sides of the cell using an acrylic adhesive (thickness 20 μm).

  The liquid crystal display devices 201 to 209 were manufactured by the above method.

<Evaluation of liquid crystal display device>
Each of the liquid crystal display devices produced above was subjected to the following evaluations.

[Measurement of contrast ratio]
A white image and a black image are displayed on each of the manufactured liquid crystal display devices, and an XYZ display system in an azimuth angle 45 ° direction and a polar angle 60 ° direction of the display screen is used using a product name “EZ Contrast 160D” manufactured by ELDIM. The Y value was measured. Then, the contrast ratio (YW / YB) in the oblique direction was calculated from the Y value (YW) in the white image and the Y value (YB) in the black image. An azimuth angle of 45 ° represents an azimuth rotated 45 ° counterclockwise when the long side of the panel is 0 °, and a polar angle of 60 ° is when the front direction of the display screen is 0 °. Represents a direction inclined at an angle of 60 °. The above measurement was performed in a dark room at a temperature of 23 ° C. and a relative humidity of 55%. A higher value indicates a higher contrast and is preferable.

[Evaluation of 3D effect]
3D images are displayed on each of the liquid crystal display devices produced above, and the attached active shutter type “Regza 3D Glass” is used to perform a sensory evaluation of 3D stereoscopic effect by 10 researchers according to the following criteria, and the average of the 10 people The value was determined.

3: The stereoscopic effect is very high 2: The stereoscopic effect is high 1: The stereoscopic effect is slightly poor 0: The stereoscopic effect is not felt at all [Evaluation of unevenness in image quality]
Each liquid crystal display device was treated for 750 hours in an environment of 80 ° C. and 90% relative humidity, and then conditioned for 24 hours in an environment of 25 ° C. and 55% relative humidity. The difference between the three-dimensional effect and the three-dimensional effect at the 75% point (end) from the center on the diagonal line is subjected to sensory evaluation by 10 researchers according to the following criteria, and the average value of 10 evaluators is obtained. This was used as a measure of image unevenness resistance.

3: There is no difference in the stereoscopic effect between the central part and the edge part 2: There is almost no difference in the stereoscopic effect between the central part and the edge part 1: There is a difference in stereoscopic effect between the central part and the edge part 0: Very large difference in three-dimensional effect between the central portion and the end portion Table 3 shows the results obtained as described above.

  As is apparent from the results shown in Table 3, the transverse electric field type switching mode type (IPS mode type) liquid crystal display device incorporating the roll-shaped circularly polarizing plate of the present invention has a contrast of the displayed image as compared with the comparative example. It is high, it is excellent in 3D stereoscopic effect, and it turns out that the dispersion | variation in the center part of a stereoscopic effect after preserve | saving in a high-temperature, high-humidity environment and an edge part is small.

Example 3
<< Production of organic EL display device >>
The Galaxy S manufactured by Samsung Electronics Co., Ltd., which is an organic EL display device, was disassembled, the polarizing plate placed on the touch panel was removed, and the glass surface of the touch panel was washed.

  Next, the circularly polarizing plates 101 to 109 produced in Example 1 are attached using an acrylic pressure-sensitive adhesive (thickness 20 μm) so that each protective film is on the touch panel side, and the organic EL display devices 301 to 309 are attached. Produced.

<< Evaluation of organic EL display >>
Next, the following evaluations were performed on each of the produced organic EL display devices.

[Evaluation of front luminance unevenness resistance]
Each of the produced organic EL display devices was treated in a high-temperature and high-humidity environment of 60 ° C. and a relative humidity of 90% for 1500 hours, and then conditioned for 20 hours in an environment of 25 ° C. and a relative humidity of 60%.

  Next, the front luminance is calculated for a total of 9 points of 25%, 50% and 75% points from the center point on the diagonal of the screen and the center on the diagonal, and the average luminance of 9 points is set to 100, and the maximum luminance and the minimum luminance are obtained. A difference (Δ luminance,%) was obtained, and front luminance unevenness resistance was evaluated according to the following criteria. The luminance was measured by using a spectral radiance meter CS-1000 (manufactured by Konica Minolta Sensing) and measuring the light emission luminance from the front (2 ° viewing angle front luminance).

A: Δ luminance is less than 1.0% B: Δ luminance is 1.0% or more and less than 2.0% Δ: Δ luminance is 2.0% or more and less than 5.0% Yes x: Δ luminance is 5.0% or more [Evaluation of reflectance unevenness resistance]
Each of the produced organic EL display devices was treated in a high-temperature and high-humidity environment of 60 ° C. and a relative humidity of 90% for 1500 hours, and then conditioned for 20 hours in an environment of 25 ° C. and a relative humidity of 60%.

  Next, the reflectivity is measured for a total of 9 points of 25%, 50%, and 75% points from the center point of the screen diagonal and the center on the diagonal line. A difference in minimum reflectance (Δ reflectance,%) was obtained, and reflectance unevenness resistance was evaluated according to the following criteria.

  The reflectance was measured by using a spectrocolorimeter CM2500d (manufactured by Konica Minolta Sensing) and measuring the reflectance at a wavelength of 550 nm.

A: Δ reflectivity is less than 0.3% O: Δ reflectivity is 0.3% or more and less than 0.5% Δ: Δ reflectivity is 0.5% or more, 1.0 X: Δ reflectivity is 1.0% or more Table 4 shows the results obtained.

  As is clear from the results shown in Table 4, the organic EL display device incorporating the roll-shaped circularly polarizing plate of the present invention has a front brightness after being stored for a long time in a high temperature and high humidity environment as compared with the comparative example. It can be seen that it is excellent in unevenness resistance and reflectance unevenness resistance.

4 Laminated body 5 Stretched laminated body 6 Diagonal stretched tenter 7-1 Trajectory of outer film holding means 7-2 Trajectory of inner film holding means 8-1 Outer film holding start point 8-2 Inner film holding start point 9 -1 Outer film holding end point 9-2 Inner film holding end point 10-1 Outer oblique stretching start point 10-2 Inner oblique stretching start point 11-1 Outer oblique stretching end point 11-2 Inner oblique stretching end point 12 -1 Guide roller on the tenter inlet side 12-2 Guide roller on the tenter outlet side 13 Film stretching direction 14-1 Transport direction of laminate before oblique stretching 14-2 Transport direction of stretched laminate after oblique stretching Wo Diagonal stretching Previous film width W Film width after oblique stretching

Claims (9)

In the production method of a roll-shaped circularly polarizing plate for producing a roll-shaped circularly polarizing plate in which at least a first protective film and a polarizer are laminated,
The polarizer is produced by a step of laminating a hydrophilic polymer layer on a thermoplastic resin layer by a coating method and a step of stretching to have an inclination of 45 ° ± 10 ° with respect to the transport direction,
The in-plane phase value Ro of the first protective film satisfies the condition defined by the following formula (i),
And a step of bonding the first protective film and the polarizer so that an angle formed between the slow axis of the first protective film and the absorption axis of the polarizer is 45 ° ± 10 °. The manufacturing method of the roll-shaped circularly-polarizing plate characterized by the above-mentioned.
Formula (i)
80 ≦ Ro ≦ 200
Wherein is represented by _{Ro = (n x -n y)} × d, n x is a refractive index in a slow axis direction in a plane of the film, n _y is the direction perpendicular to the slow axis in the film plane Each represents a refractive index, and d represents the thickness (nm) of the film. Each refractive index is a value measured at an optical wavelength of 590 nm in an environment of a temperature of 23 ° C. and a relative humidity of 55% RH. ]   2. The polarizer according to claim 1, wherein the polarizer is stretched so as to have an inclination of 45 ° ± 10 ° with respect to the transport direction, and is contracted within a range of 10 to 40% in a direction perpendicular to the stretching axis. The manufacturing method of the roll-shaped circularly-polarizing plate of description.   3. The method for producing a roll-shaped circularly polarizing plate according to claim 1, wherein a thickness of the polarizer after stretching is in a range of 0.5 to 10 μm.   The stretch ratio for stretching the polarizer so as to have an inclination of 45 ° ± 10 ° with respect to the transport direction is in the range of 2.0 to 7.0 times. The manufacturing method of the roll-shaped circularly-polarizing plate as described in any one.   The hydrophilic polymer layer forming the polarizer is a coated body of polyvinyl alcohol resin, and the dichroic material used in the dyeing step is an iodine-containing compound. The manufacturing method of the roll-shaped circularly-polarizing plate of one term.   The roll-shaped circularly polarized light according to any one of claims 1 to 5, further comprising a step of peeling the thermoplastic resin layer after the first protective film and the polarizer are bonded together. A manufacturing method of a board.   The first protective film includes a cellulose ester having an average acyl substitution degree of 1.5 to 2.7 and extending in a range of 1.05 to 1.50 times in the width direction or the longitudinal direction. The manufacturing method of the roll-shaped circularly-polarizing plate as described in any one of Claim 1 to 6 characterized by the above-mentioned.   An organic electroluminescence display device comprising a circularly polarizing plate manufactured by the method for manufacturing a rolled circularly polarizing plate according to any one of claims 1 to 7.   A lateral electric field type switching mode liquid crystal display device comprising a liquid crystal cell and two polarizing plates sandwiching the liquid crystal cell. A transverse electric field type switching mode type liquid crystal display device, wherein a circularly polarizing plate manufactured by a manufacturing method of a polarizing plate is disposed.

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