JP2009047776A - Alignment layer, alignment film, optical film, polarizing plate and liquid crystal display apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an alignment layer which has high durability and good adhesion to a polymer film and an optical anisotropic layer formed of a liquid crystal composition and to provide an optical film of high durability. <P>SOLUTION: The alignment layer is consisting essentially of polyvinyl alcohol and contains at least one highly saponified polyvinyl alcohol with average saponification degree of ≥95% and at least one modified polyvinyl alcohol having a cross-linkable group in a molecule. Further the optical film has the optical anisotropic layer which is formed of the liquid crystal composition on the alignment layer. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an alignment film and an alignment film that can control the alignment of liquid crystal, and an optical film, a polarizing plate, and a liquid crystal display device using the alignment film.

  Various optical films produced by utilizing the orientation of a liquid crystal composition have been proposed as optical compensation films used for liquid crystal display devices and the like. This optical film is produced, for example, by applying a polymerizable liquid crystal composition to the alignment film surface to obtain a desired alignment state, and then fixing the state by polymerization. However, some of these optical films have insufficient adhesion between the optically anisotropic layer and the alignment film, and peeling occurs when used for a long time, and improvement in durability is required. .

For example, in Patent Document 1, as an optical compensation sheet having excellent durability, an optical compensation sheet comprising a transparent support, an alignment film made of a polymer, and an optical anisotropic layer made of a liquid crystal compound in this order. Has proposed an optical compensation sheet characterized in that the polymer of the alignment film and the liquid crystal compound of the optically anisotropic layer are chemically bonded via the interface of these layers.
However, further improvements in durability are required for optical films and the like used in liquid crystal display devices.

Patent Document 2 discloses a liquid crystal alignment film comprising at least a non-modified polyvinyl alcohol having a polymerization degree of 500 or more and a modified polyvinyl alcohol, and a rod-like or disk-like liquid crystal on the film is homeotropically or hybrid-oriented. The resulting liquid crystalline optical film is disclosed.
JP 9-152509 A JP 2006-243025 A

By the way, when an alignment film is used for producing an optical film, generally, the alignment film is formed on the surface of a polymer film, and an optically anisotropic layer made of a liquid crystal composition is formed thereon. . Not only is the alignment film itself highly durable, but if an alignment film with high adhesion to the polymer film and the optically anisotropic layer respectively positioned above and below is obtained, the durability as an optical film is improved. Can contribute to improving the durability of a polarizing plate having a protective film and a liquid crystal display device incorporating the same.
Accordingly, an object of the present invention is to provide an alignment film that is highly durable and has good adhesion to an optically anisotropic layer formed from a polymer film and a liquid crystal composition.
Moreover, this invention makes it a subject to provide the oriented film, the optical film, and polarizing plate excellent in durability, and a liquid crystal display device having the same.

Means for solving the above-mentioned problems are as follows.
[1] An alignment film containing polyvinyl alcohol as a main component, which contains at least one kind of high-saponification degree polyvinyl alcohol having an average saponification degree of 95% or more and at least one kind of modified polyvinyl alcohol having a crosslinkable group in the molecule. An alignment film, wherein the content of the modified polyvinyl alcohol is smaller than that of the high saponification degree polyvinyl alcohol.
[2] The alignment film according to [1] or [2], wherein an average saponification degree of the modified polyvinyl alcohol is 95% or less.
[3] The oriented film according to [1] or [2], wherein an average saponification degree of the modified polyvinyl alcohol is 70 to 90%.
[4] The alignment film according to any one of [1] to [3], wherein the crosslinkable group of the modified polyvinyl alcohol is any one of an unsaturated polymerizable group, an epoxy group, and an aziridinyl group.
[5] The alignment film according to any one of [1] to [4], wherein the crosslinkable group of the modified polyvinyl alcohol is an ethylenically unsaturated polymerizable group.
[6] The alignment film according to any one of [1] to [5], wherein the ratio of the high saponification degree polyvinyl alcohol is 85% by mass or more based on the total mass of all the polyvinyl alcohols contained.
[7] The alignment film according to any one of [1] to [6], wherein a ratio of the high saponification degree polyvinyl alcohol is 90% by mass or more based on a total mass of all the polyvinyl alcohols contained.
[8] The alignment film according to any one of [1] to [7], wherein a ratio of the high saponification degree polyvinyl alcohol is 95% by mass or more based on a total mass of all the polyvinyl alcohols contained.
[9] The alignment film according to any one of [1] to [8], wherein the average degree of polymerization of the high saponification degree polyvinyl alcohol is 800 or more.
[10] The alignment film according to any one of [1] to [9], wherein the average degree of polymerization of the modified polyvinyl alcohol is 800 or less.

[11] An alignment film having a polymer film and an alignment film of any one of [1] to [10] on the polymer film.
[12] The oriented film according to [11], wherein the polymer film is a polymer film containing cellulose acylate as a main component.
[13] An optical film comprising the alignment film of [11] or [12] and an optically anisotropic layer formed from a liquid crystal composition on the alignment film.
[14] The optical system according to [13], wherein the optically anisotropic layer is a layer formed by curing a curable liquid crystal composition containing a liquid crystal compound having a crosslinkable group in an aligned state. the film.
[15] The optical film of [14], wherein the crosslinkable group possessed by the liquid crystalline compound is the same kind of crosslinkable group as the crosslinkable group possessed by the modified polyvinyl alcohol contained in the alignment film.
[16] The optical film of [15], wherein the crosslinkable group is an ethylenically unsaturated polymerizable group.
[17] A polarizing plate comprising at least a polarizing film and the optical film of any one of [1] to [15].
[18] The polarizing plate according to [17], wherein the optical film is a protective film for the polarizing film.
[19] A liquid crystal display device comprising the polarizing plate of [17] or [18].

According to the present invention, it is possible to provide an alignment film that is highly durable and has good adhesion to an optically anisotropic layer formed from a polymer film and a liquid crystal composition.
In addition, according to the present invention, it is possible to provide an optical film and a polarizing plate that are useful as members of a liquid crystal display device and the like and excellent in durability, and a liquid crystal display device having the same.

BEST MODE FOR CARRYING OUT THE INVENTION

  Hereinafter, the present invention will be described in detail. In the present specification, a numerical range represented by using “to” means a range including numerical values described before and after “to” as a lower limit value and an upper limit value.

[Alignment film]
The present invention is an alignment film comprising polyvinyl alcohol as a main component, comprising at least one kind of high-saponification degree polyvinyl alcohol having an average saponification degree of 95% or more and at least one kind of modified polyvinyl alcohol having a crosslinkable group in the molecule. It is related with the orientation film characterized by containing.
As a result of intensive studies by the present inventors, the alignment film containing polyvinyl alcohol having a high saponification degree has high durability, particularly water resistance, and an optically anisotropic layer made of a liquid crystal composition is further formed thereon. The inventors obtained knowledge that the water resistance of the entire optical film formed and formed can be dramatically improved. However, when further examination is made, the durability of the entire optical film cannot be improved because the adhesion between the alignment film containing polyvinyl alcohol having a high saponification degree and the optically anisotropic layer made of the liquid crystal composition is low. I found out there was a problem. This is thought to be due to the high saponification degree polyvinyl alcohol having high crystallinity and high cohesion between the polyvinyl alcohols.
Next, in order to ensure the adhesion between the alignment film and the optically anisotropic layer made of the liquid crystal composition, an attempt was made to add polyvinyl alcohol having a crosslinkable group to the alignment film, but the adhesion was improved. However, it was found that the water resistance improvement effect obtained by using polyvinyl alcohol having a high saponification degree was lowered.
As a result of further investigation, surprisingly, a polyvinyl alcohol having a crosslinkable group in the molecule was added to the polyvinyl alcohol having a high saponification degree in a proportion smaller than that of the polyvinyl alcohol having a high saponification degree. The inventors have found that the adhesion to the optically anisotropic layer formed from the liquid crystal composition can be remarkably improved while maintaining the water resistance by alcohol, and have completed the present invention.
Modified polyvinyl alcohol having a crosslinkable group in the molecule has a small surface free energy of the molecule compared to polyvinyl alcohol having a high degree of saponification, and therefore is unevenly distributed on the surface of the alignment film and adheres to the optically anisotropic layer. It is thought to contribute to improvement. For example, when forming an optically anisotropic layer, even if the curing reaction proceeds at a relatively low temperature, the crosslinkable group of the modified polyvinyl alcohol is unevenly distributed at the interface between the alignment film and the optically anisotropic layer. The adhesion is improved. Therefore, when forming the optically anisotropic layer, the polymerization can be performed at a lower temperature, the alignment disorder due to the thermal motion can be further reduced, and the optically anisotropic layer having desired optical characteristics can be formed into a thinner film. The alignment film of the present invention is effective in terms of reduction in film thickness unevenness and the like.

Hereinafter, materials and manufacturing methods that can be used for manufacturing the alignment film of the present invention will be described in detail.
The alignment film of the present invention has polyvinyl alcohol as a main component and has at least one highly saponified polyvinyl alcohol having an average saponification degree of 95% or more, a crosslinkable group in the molecule, and an average saponification from the high saponification degree polyvinyl alcohol. At least one kind of polyvinyl alcohol having a low degree.
By using polyvinyl alcohol having a high saponification degree, the cohesive strength in the film can be increased due to its crystallinity, and water resistance or durability under high humidity can be increased. On the other hand, by mixing polyvinyl alcohol having a crosslinkable group in the molecule, adhesion with an optically anisotropic layer formed from a liquid crystal composition laminated on the alignment film can be ensured.
“Polyvinyl alcohol as a main component” means that 50% by mass or more of polyvinyl alcohol is contained.

  The alignment film of the present invention preferably contains the high saponification degree polyvinyl alcohol at a higher mass ratio than the modified polyvinyl alcohol. The proportion of the high saponification degree polyvinyl alcohol is preferably 85% by mass or more, more preferably 90% by mass or more, and 95% by mass or more with respect to the total mass of the total polyvinyl alcohol contained. Is more preferable. Increasing the proportion of polyvinyl alcohol with a high degree of saponification increases the cohesive force of the alignment film and improves water resistance. On the other hand, the content of the modified polyvinyl alcohol is preferably 0.1 to 15% by mass, more preferably 0.5 to 10% by mass, based on the total mass of all the polyvinyl alcohol contained. More preferably, it is 1.0-8.0 mass%. The alignment film of the present invention may contain two or more of the aging polyvinyl alcohol and the modified polyvinyl alcohol. Further, it may contain polyvinyl alcohol that does not belong to any of the above, but all polyvinyl alcohols contained in the alignment film of the present invention belong to either the highly saponified polyvinyl alcohol or the unmodified polyvinyl alcohol. It is preferable.

(Highly saponified polyvinyl alcohol)
High saponification degree The average saponification degree of polyvinyl alcohol is 95% or more, preferably 97% or more, and more preferably 98% or more.

  In the present invention, the average degree of polymerization of the highly saponified polyvinyl alcohol is preferably 500 to 5,000, more preferably 600 to 3,000, and particularly preferably 800 to 2,000. Polyvinyl alcohol having a high degree of polymerization has low water solubility and can further improve the water resistance of the alignment film. On the other hand, since the water solubility is lowered, the handling property of the aqueous solution for film formation is lowered. By setting it as the said range, handling property and water resistance can be made compatible.

  Commercially available unmodified polyvinyl alcohol may be used as the highly saponified polyvinyl alcohol. Examples of the unmodified polyvinyl alcohol having an average polymerization degree within the above range include PVA110, PVA117, PVA124, and PVA135 manufactured by Kuraray Co., Ltd.

(Modified polyvinyl alcohol having a crosslinkable group in the molecule)
The alignment film of the present invention contains at least one modified polyvinyl alcohol having a crosslinkable group in the molecule. The crosslinkable group of the modified polyvinyl alcohol is preferably a polymerizable group. When the modified polyvinyl alcohol having a polymerizable group is used for forming the alignment film and the liquid crystalline molecule having the polymerizable group is used for forming the optically anisotropic layer, the interface between the optically anisotropic layer and the alignment film is reduced. Can be chemically bonded. Thereby, the durability of the optical film having the alignment film can be improved. The modified polyvinyl alcohol having a polymerizable group can be obtained by introducing a repeating unit having a polymerizable group into polyvinyl alcohol or by reacting a compound having a polymerizable group with polyvinyl alcohol or modified polyvinyl alcohol.

  When the modified polyvinyl alcohol has a polymerizable crosslinkable group, it undergoes a polymerization reaction with the polymerizable group (Q) of the liquid crystalline molecule described later, and chemically bonds between the liquid crystalline molecule and the modified polyvinyl alcohol. As a result, a chemical bond is formed at the interface between the optically anisotropic layer and the alignment film. Accordingly, the polymerizable group of the modified polyvinyl alcohol is preferably capable of undergoing a polymerization reaction with the polymerizable group (Q) of the liquid crystal molecule described later, and is preferably selected according to the type of Q. As described later, the polymerizable group (Q) of the liquid crystal molecule is preferably an unsaturated polymerizable group (examples Q1 to Q7 described later), an epoxy group (Q8) or an aziridinyl group (Q9). A saturated polymerizable group is more preferable, and an ethylenically unsaturated polymerizable group (Q1 to Q6) is particularly preferable. Accordingly, the polymerizable group of the modified polyvinyl alcohol is also preferably an unsaturated polymerizable group, an epoxy group or an aziridinyl group, more preferably an unsaturated polymerizable group, and an ethylenically unsaturated polymerizable group. Particularly preferred is a group.

  In the modified polyvinyl alcohol, it is preferable that the main chain and the polymerizable group are bonded via a linking group without being directly bonded. Examples of the linking group include -O-, -O-CO-, -O-CO-NH-, -O-CO-NH-alkylene group-, -O-CO-NH-alkylene group -O-,- O-CO-NH-alkylene group -CO-O-, -O-CO-NH-alkylene group -O-CO-, -O-CO-NH-alkylene group -CO-NH-, -O-CO-alkylene -O-CO-, -O-CO-arylene group -O-alkylene group -O-CO-, -O-CO-arylene group -O-alkylene group -O-, -O-CO-arylene group -O -Alkylene group- and -O-alkylene group-O-CO- are included (the left side is bonded to the main chain and the right side is bonded to the polymerizable group). The alkylene group may have a branched or cyclic structure. The number of carbon atoms of the alkylene group is preferably 1-30, more preferably 1-20, still more preferably 1-15, and even more preferably 1-12. The arylene group is preferably phenylene or naphthylene, more preferably phenylene, and still more preferably p-phenylene. The arylene group may have a substituent. Examples of the substituent of the arylene group include a halogen atom (F, Cl, Br), carboxyl, cyano, nitro, carbamoyl, sulfamoyl, alkyl group, cycloalkyl group, alkoxy group, alkylthio group, acyl group, acyloxy group, alkyl Substituted carbamoyl groups, alkyl-substituted sulfamoyl groups, amide groups, sulfonamido groups and alkylsulfonyl groups are included.

  The alkyl group may have a branch. The number of carbon atoms in the alkyl group is preferably 1-20, more preferably 1-15, still more preferably 1-10, and even more preferably 1-6. The cycloalkyl group is preferably cyclohexyl. The alkoxy group may have a branch. The number of carbon atoms in the alkoxy group is preferably 1-20, more preferably 1-15, still more preferably 1-10, and even more preferably 1-6. The alkylthio group may have a branch. The number of carbon atoms in the alkylthio group is preferably 1-20, more preferably 1-15, still more preferably 1-10, and even more preferably 1-6. The acyl group preferably has 2 to 20 carbon atoms, more preferably 2 to 15, more preferably 2 to 10, and still more preferably 2 to 6. The number of carbon atoms of the acyloxy group is preferably 2-20, more preferably 2-15, still more preferably 2-10, and even more preferably 2-6.

  The number of carbon atoms of the alkyl-substituted carbamoyl group is preferably 2-20, more preferably 2-15, still more preferably 2-10, and even more preferably 2-6. . The alkyl part of the alkyl-substituted carbamoyl group may further have a substituent (eg, alkoxy group). The number of carbon atoms in the alkyl-substituted sulfamoyl group is preferably 1-20, more preferably 1-15, still more preferably 1-10, and even more preferably 1-6. . The alkyl portion of the alkyl-substituted sulfamoyl group may further have a substituent (eg, an alkoxy group). The number of carbon atoms in the amide group is preferably 2-20, more preferably 2-15, still more preferably 2-10, and even more preferably 2-6. The number of carbon atoms in the sulfonamide group is preferably 1-20, more preferably 1-15, still more preferably 1-10, and even more preferably 1-6. The number of carbon atoms in the alkylsulfonyl group is preferably 1-20, more preferably 1-15, still more preferably 1-10, and even more preferably 1-6. The alkyl part of the alkylsulfonyl group may further have a substituent (eg, an alkoxy group).

The modified polyvinyl alcohol may have two or more polymerizable groups.
Preferable examples of the modified polyvinyl alcohol that can be used in the present invention include modified polyvinyl alcohol having a repeating unit having a polymerizable group represented by the following formula (II).

In the formula (II), L ¹¹ represents a single bond, —CO—, —CO—NH—, —CO—NH-alkylene group—, —CO—NH-alkylene group —O—, —CO—NH-alkylene group. -CO-O-, -CO-NH-alkylene group -O-CO-, -CO-NH-alkylene group -CO-NH-, -CO-alkylene group -O-CO-, -CO-arylene group -O -Alkylene group-O-CO-, -CO-arylene group-O-alkylene group-O-, -CO-arylene group-O-alkylene group- and -alkylene group-O-CO- selected from the group consisting of It is a group. -CO-NH-alkylene group-, -CO-NH-alkylene group-O-, -CO-NH-alkylene group-O-CO-, -CO-arylene group-O-alkylene group-O-CO-,- CO-arylene group-O-alkylene group-O-, -CO-arylene group-O-alkylene group- and -alkylene group-O-CO- are preferred, and -CO-NH-alkylene group-O-CO- is particularly preferred. preferable. The alkylene group may have a branched or cyclic structure. The number of carbon atoms of the alkylene group is preferably 1-30, more preferably 1-20, still more preferably 1-15, and even more preferably 1-12. The arylene group is preferably phenylene or naphthylene, more preferably phenylene, and most preferably p-phenylene. The arylene group may have a substituent. Examples of the substituent for the arylene group are the same as the examples of the substituent for the arylene group described above. In the formula (II), Q is a polymerizable group. As described above, the polymerizable group is preferably the same group as the polymerizable group (Q) of the liquid crystal molecule. Examples of repeating units having a polymerizable group are shown below.

  The modified polyvinyl alcohol is produced, for example, by reacting a commercially available unmodified poly with bil alcohol and a reagent such as methacryloyloxyethyl isocyanate or 4- (4-acryloyloxybutoxy) benzoic acid in the presence of a catalyst. be able to. As commercially available unmodified polyvinyl alcohol used as a raw material, PVA103, PVA203, and PVA205 (all manufactured by Kuraray) can be used. This method is described in detail in JP-A-9-152509 and other publications.

  The modified polyvinyl alcohol used in the present invention preferably has an average saponification degree equal to or less than the average saponification degree of the high saponification degree polyvinyl alcohol, that is, the average saponification degree is preferably 95% or less, and 90% or less. It is more preferable that By reducing the saponification degree of the modified polyvinyl alcohol, the difference in surface energy from the highly saponified polyvinyl alcohol molecules contained more in the alignment film increases, and the polyvinyl molecules having a crosslinkable group in the molecule This is preferable because it tends to be unevenly distributed. The lower limit value of the average degree of saponification of the modified polyvinyl alcohol is not particularly limited, but generally it is preferably 95% or more, more preferably 97% or more.

  The average degree of polymerization of the modified polyvinyl alcohol having a crosslinkable group in the molecule is preferably 800 or less, more preferably 600 or less, and particularly preferably 400 or less. Decreasing the degree of polymerization facilitates movement of the molecule, and polyvinyl alcohol molecules having a crosslinkable group in the molecule tend to be unevenly distributed on the surface, which is preferable. Although there is no restriction | limiting in particular about the lower limit of the average degree of polymerization of the said modified polyvinyl alcohol, Generally, it is preferable that it is 50 or more, and it is more preferable that it is 100 or more.

In the present invention, the ratio of the modified polyvinyl alcohol to the total mass of all the polyvinyl alcohols in the alignment film is preferably 0.1 to 15% by mass, and more preferably 0.3 to 10% by mass. More preferably, it is 0.5-5 mass%.
By setting the blending amount in the above range, it is possible to increase the cohesive force of the alignment film and ensure water resistance while ensuring interface adhesion.

The alignment film of the present invention may contain other polyvinyl alcohol or additives as long as the effects of the present invention are not impaired. For example, a crosslinking agent can be used to cure the alignment film. Examples of the crosslinking agent include aldehydes, N-methylol compounds, dioxane derivatives, compounds that act by activating carboxyl groups, active vinyl compounds, active halogen compounds, isoxazole, and dialdehyde starch. More specifically, compounds described in paragraph numbers [0023] to [0024] in JP-A No. 2002-62426 may be mentioned. Aldehydes having high reaction activity, particularly glutaraldehyde are preferred.
However, if the crosslinking agent is added too much, the water resistance tends to decrease. Therefore, when the crosslinking agent is used, the addition amount is preferably small, and is 0 to 10% by mass relative to the total polyvinyl alcohol. Is preferable, and it is more preferable that it is 0-5 mass%.

-Alignment film forming method The alignment film basically comprises at least one of the high saponification degree polyvinyl alcohol, which is an alignment film forming material, at least one of the modified polyvinyl alcohol, and a cross-linking agent added as required. It can be formed from the containing composition. The composition is preferably prepared as a coating solution. The composition prepared as a coating solution can be formed by coating the surface of a support such as a polymer film, followed by drying by heating (crosslinking). As described above, the crosslinking reaction can be carried out at any time after coating on the transparent support. For the preparation of the coating solution, it is preferable to use a mixed solvent of an organic solvent (eg, methanol) and water having an antifoaming action. The ratio by mass is water: methanol greater than 0 and 99 or less: less than 100, preferably 1 or more, and more preferably greater than 0 and 91 or less: less than 100, 9 or more. Thereby, generation | occurrence | production of a bubble is suppressed and the defect of the layer surface of an alignment film and also an optically anisotropic layer reduces.

  The alignment film forming composition is preferably applied by spin coating, dip coating, curtain coating, extrusion coating, rod coating, roll coating, or the like. In particular, the rod coating method or the extrusion coating method is preferable. Although there is no restriction | limiting in particular about an application quantity, It is preferable to set it as the application quantity from which the film thickness after drying of alignment film becomes about 0.1-10 micrometers.

  After coating, the coating is dried to remove the solvent in the coating solution to form a film. You may heat as needed at the time of drying. Drying is preferably performed at 20 ° C to 110 ° C. In order to form a sufficient crosslink, 60 ° C to 100 ° C is preferable, and 80 ° C to 100 ° C is particularly preferable. The drying time is preferably 1 minute to 36 hours, more preferably 1 minute to 30 minutes. The pH is also preferably set to an optimum value for the cross-linking agent to be used, and when glutaraldehyde is used, the pH is preferably 2.5 to 5.5.

  The surface of the formed film may be rubbed if desired. For the rubbing treatment, a treatment method widely adopted as a liquid crystal alignment treatment process of LCD can be applied. That is, a method of obtaining the orientation by rubbing the surface of the orientation film in a certain direction using paper, gauze, felt, rubber, nylon, polyester fiber or the like can be used. Generally, it is carried out by rubbing using a cloth in which fibers having uniform length and thickness are flocked on average.

[Oriented film]
The present invention also relates to a polymer film and an alignment film having the alignment film of the present invention thereon. The oriented film of the present invention is excellent in water resistance, has good adhesion between the polymer film and the oriented film, and is excellent in durability as the entire oriented film. The alignment film of the present invention is used for controlling the alignment of a liquid crystal composition, and is useful for producing an optical film used as an optical compensation film for a liquid crystal display device.

  The polymer film is preferably transparent from the viewpoint that it can be used as it is in a liquid crystal display device or the like. Specifically, the polymer film is preferably a transparent support having a light transmittance of 80% or more. Examples of polymer films that can be used include cellulose ester, polycarbonate, polysulfone, polyethersulfone, polyacrylate and polymethacrylate films. Among these, since the adhesion to the alignment film of the present invention is higher, a cellulose ester film containing a cellulose ester as a main component is preferable, a cellulose acylate film containing a cellulose acylate as a main component is more preferable, and acetyl cellulose Is more preferable, and a triacetyl cellulose film containing triacetyl cellulose as a main component is even more preferable. Including the polymer film as a “main component” means containing 50% by mass or more of the raw material. The polymer film is preferably formed by a solvent cast method.

In general, the thickness of the polymer film is preferably 20 to 500 μm, and more preferably 40 to 200 μm.
In order to further improve the adhesion between the polymer film and the alignment film of the present invention provided thereon, surface treatment (eg, glow discharge treatment, corona discharge treatment, ultraviolet (UV) treatment, flame treatment) is performed on the polymer film. May be. Furthermore, an adhesive layer (undercoat layer) may be provided between the polymer film and the alignment film. Moreover, in order to give the slip property in a conveyance process or to prevent sticking with the back surface and the surface after winding up, the inorganic particle whose average particle diameter is about 10-100 nm is 5% by solid content mass ratio. You may form the polymer layer which mixed -40% on the back surface (surface on the opposite side to the surface which forms an alignment film and an optical anisotropic layer) of a polymer film. The polymer layer can be formed by a coating method or a co-casting method.

From the viewpoint of durability, the surface of the polymer film on the side in contact with the alignment film is preferably made hydrophilic. Hydrophilization can also be achieved by the above-exemplified surface treatment, but among these, it is preferable to make hydrophilic by applying a liquid containing at least an organic solvent, a metal hydroxide salt, water, a compatibilizing agent, and a surfactant to the surface. . This hydrophilization method is particularly effective for a polymer film containing a cellulose-based polymer such as cellulose acylate. The liquid used for the hydrophilization is preferably an alkaline liquid. When the surface of a polymer film containing a cellulosic polymer such as cellulose acylate is treated with an alkaline solution, saponification proceeds, thereby making it hydrophilic.
The organic solvent preferably dissolves the metal hydroxide salt and does not dissolve the cellulose acylate film, and specific examples thereof include methanol, ethanol, isopropanol, isobutanol and the like.
Specific examples of the metal hydroxide salt are preferably alkali metal hydroxides, and include sodium hydroxide, potassium hydroxide and the like.
The compatibilizing agent is preferably a compound that forms a uniform solution by adding the agent when water, an organic solvent, and a metal hydroxide salt are mixed. Specific examples thereof include diethylene glycol, Propylene glycol, polyhydric alcohol and the like are included.
The surfactant is preferably a nonionic surfactant, and specific examples thereof include polyoxyethylene lauryl ether, polyoxyethylene nonyl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene stearyl ether, Oxyethylene oleyl ether, polyoxyethylene behenyl ether, and the like.

  The hydrophilization treatment can be carried out by applying the liquid onto the surface of the polymer film, leaving it under heating as desired for 10 to 120 seconds, and then washing with water. Before the hydrophilization treatment, the film may be heated to about 30 to 80 ° C. if desired. Further, after coating, the film may be heated to about 30 to 80 ° C. as desired when the film is allowed to stand. Washing with water may be performed a plurality of times, and draining with an air knife or the like is preferable because the number of times of washing with water can be reduced. From the viewpoint of handleability and the like, the surface tension of the liquid is preferably 15 to 65 mN / m, and the viscosity is preferably 0.6 to 20 mPa · s.

In addition, when the optical film of the present invention described later is used as an optical compensation film for a liquid crystal display device, the polymer film as a support has an optical anisotropy so as not to impair the optical compensation ability of the optical anisotropic layer. Is preferably small, and it is also preferable that the wavelength dispersion of the retardation is small. Specifically, the in-plane retardation of the support is preferably 10 nm or less, and more preferably 5 nm or less. Further, the wavelength dispersibility is specifically the ratio Re (400) / Re (700) between the in-plane retardation Re (400) at a wavelength of 400 nm and the in-plane retardation Re (700) at a wavelength of 700 nm. It is preferable that it is less than 1.2.
However, this is not the case in an aspect in which the optical characteristics necessary for the optical compensation capability are obtained by actively utilizing the optical characteristics of the polymer film.

[Optical film]
The present invention also relates to an optical film having a polymer film, an alignment film of the present invention thereon, and an optically anisotropic layer formed thereon from a liquid crystal composition. The optical film of the present invention is excellent in durability, particularly water resistance, is excellent in adhesion of each layer, hardly causes defects such as peeling, and is excellent in durability as an entire optical film. As a result, it can contribute to the improvement of the durability of the polarizing plate having the optical film of the present invention as a protective film and the liquid crystal display device having the optical film of the present invention.

(Optically anisotropic layer)
The optically anisotropic layer is formed from a liquid crystal composition. Among these, a layer formed by curing a curable liquid crystal composition containing a liquid crystal compound having a crosslinkable group in an aligned state is preferable.
-Liquid crystal compound The liquid crystal composition used for forming the optically anisotropic layer contains at least one liquid crystal compound. The liquid crystal compound is preferably a polymerizable liquid crystal compound having a polymerizable group. Liquid crystal compounds are generally classified into rod-like liquid crystal compounds and discotic liquid crystal compounds based on their molecular shapes. In the present invention, any liquid crystal compound may be used.
-Rod-like liquid crystal compounds As rod-like liquid crystal compounds, azomethines, azoxys, cyanobiphenyls, cyanophenyl esters, benzoic acid esters, cyclohexanecarboxylic acid phenyl esters, cyanophenylcyclohexanes, cyano-substituted phenylpyrimidines, alkoxy-substituted compounds Phenylpyrimidines, phenyldioxanes, tolanes and alkenylcyclohexylbenzonitriles are preferably used. In addition to the low-molecular liquid crystals as described above, polymer liquid crystals can also be used. As the rod-like liquid crystal compound, those having a partial structure capable of causing polymerization or crosslinking reaction by actinic rays, electron beams, heat, or the like are suitably used. The number of the partial structures is 1 to 6, preferably 1 to 3. As described above, the rod-like liquid crystalline molecules that can be used in the present invention preferably have a polymerizable group in order to fix the alignment state. The polymerizable group is preferably a radically polymerizable unsaturated group, and specific examples thereof include a polymerizable group and a polymerizable liquid crystal compound described in JP-T-1000-514202 or JP-A-2002-62427. There is no restriction | limiting in particular about the orientation form of the rod-shaped liquid crystalline molecule in the said optically anisotropic layer. The orientation may be any of vertical, horizontal, and hybrid with respect to the layer surface.

  As described above, it is more preferable to fix the alignment of the rod-like liquid crystalline molecules by polymerization. Chem. 190, 2255 (1989), Advanced Materials 5, 107 (1993), US Pat. Nos. 4,683,327, 5,622,648 and 5,770,107, WO 95/22586, 95/24455, 97/97. No. 0600, No. 98/23580, No. 98/52905, JP-A-1-272551, No. 6-16616, No. 7-110469, No. 11-80081, and Japanese Patent Application No. 2001-64627 These compounds can be used. More preferably, it is a compound represented by the following general formula (II).

^{(IV) Q 1 -L 1 -Cy} 1 -L 2 - (Cy 2 -L 3) n -Cy 3 -L 4 -Q 2
In the formula, Q ¹ and Q ² are each independently a polymerizable group, L ¹ and L ⁴ are each independently a divalent linking group, and L ² and L ³ are each independently a single bond or a divalent group. It is a linking group, Cy ¹ , Cy ² and Cy ³ are divalent cyclic groups, and n is 0, 1 or 2.

The polymerizable rod-like liquid crystal compound will be further described below.
^{(IV) Q 1 -L 1 -Cy} 1 -L 2 - (Cy 2 -L 3) n -Cy 3 -L 4 -Q 2
In the formula, Q ¹ and Q ² are each independently a polymerizable group. The polymerization reaction of the polymerizable group is preferably addition polymerization (including ring-opening polymerization) or condensation polymerization. In other words, the polymerizable group is preferably a functional group capable of addition polymerization reaction or condensation polymerization reaction. Examples of polymerizable groups are shown below.

  In the formula, Q is a polymerizable group, the polymerizable group (Q) in the polyvinyl alcohol having a crosslinkable group in the molecule, the polymerizable group (Q) in a discotic liquid crystal compound having a polymerizable group described later, and As described above, it is preferably an unsaturated polymerizable group (the above-mentioned examples Q1 to Q7), an epoxy group (Q8) or an aziridinyl group (Q9), and more preferably an unsaturated polymerizable group. And most preferably an ethylenically unsaturated polymerizable group (Q1 to Q6).

L ¹ and L ⁴ are each independently a divalent linking group. L ¹ and L ⁴ are each independently two selected from the group consisting of —O—, —S—, —CO—, —NR ² —, a divalent chain group, a divalent cyclic group, and combinations thereof. A valent linking group is preferred. R ² is an alkyl group having 1 to 7 carbon atoms or a hydrogen atom. R ² is preferably an alkyl group having 1 to 4 carbon atoms or a hydrogen atom, more preferably a methyl group, an ethyl group or a hydrogen atom, and most preferably a hydrogen atom. The example of the bivalent coupling group which consists of a combination is shown below. Here, the left side is coupled to Q (Q ¹ or Q ² ), and the right side is coupled to Cy (Cy ¹ or Cy ³ ).

L-1: —CO—O—divalent chain group —O—
L-2: -CO-O-divalent chain group -O-CO-
L-3: —CO—O—divalent chain group —O—CO—O—
L-4: -CO-O-divalent chain group -O-divalent cyclic group-
L-5: -CO-O-divalent chain group -O-divalent cyclic group -CO-O-
L-6: -CO-O-divalent chain group -O-divalent cyclic group -O-CO-
L-7: -CO-O-divalent chain group-O-divalent cyclic group-divalent chain group-
L-8: -CO-O-divalent chain group -O-divalent cyclic group -divalent chain group -CO-O-
L-9: -CO-O-divalent chain group -O-divalent cyclic group -divalent chain group -O-CO-
L-10: —CO—O—divalent chain group—O—CO—divalent cyclic group—
L-11: -CO-O-divalent chain group -O-CO-divalent cyclic group -CO-O-
L-12: -CO-O-divalent chain group -O-CO-divalent cyclic group -O-CO-
L-13: —CO—O—Divalent chain group—O—CO—Divalent cyclic group—Divalent chain group—
L-14: -CO-O-divalent chain group -O-CO-divalent cyclic group -divalent chain group -CO-O-
L-15: -CO-O-divalent chain group-O-CO-divalent cyclic group-divalent chain group-O-CO-
L-16: —CO—O—divalent chain group—O—CO—O—divalent cyclic group—
L-17: -CO-O-divalent chain group -O-CO-O-divalent cyclic group -CO-O-
L-18: -CO-O-divalent chain group -O-CO-O-divalent cyclic group -O-CO-
L-19: —CO—O—Divalent chain group—O—CO—O—Divalent cyclic group—Divalent chain group—
L-20: -CO-O-divalent chain group -O-CO-O-divalent cyclic group -divalent chain group -CO-O-
L-21: -CO-O-divalent chain group -O-CO-O-divalent cyclic group -divalent chain group -O-CO-

  The divalent chain group means an alkylene group, a substituted alkylene group, an alkenylene group, a substituted alkenylene group, an alkynylene group, or a substituted alkynylene group. An alkylene group, a substituted alkylene group, an alkenylene group and a substituted alkenylene group are preferred, and an alkylene group and an alkenylene group are more preferred. The alkylene group may have a branch. The alkylene group preferably has 1 to 12 carbon atoms, more preferably 2 to 10 carbon atoms, and still more preferably 2 to 8 carbon atoms. The alkylene part of the substituted alkylene group is the same as the above alkylene group. Examples of the substituent include a halogen atom. The alkenylene group may have a branch. The alkenylene group preferably has 2 to 12 carbon atoms, more preferably 2 to 10 carbon atoms, and still more preferably 2 to 8 carbon atoms. The alkenylene part of the substituted alkenylene group is the same as the alkenylene group. Examples of the substituent include a halogen atom. The alkynylene group may have a branch. The alkynylene group preferably has 2 to 12 carbon atoms, more preferably 2 to 10 carbon atoms, and still more preferably 2 to 8 carbon atoms. The alkynylene part of the substituted alkynylene group is the same as the above alkynylene group. Examples of the substituent include a halogen atom.

  Specific examples of the divalent chain group include ethylene, propylene, tetramethylene, 2-methyl-1,4-butylene, pentamethylene, hexamethylene, octamethylene, 2-butenylene, 2-butynylene and the like.

The definition and examples of the divalent cyclic group are the same as those of Cy ¹ , Cy ² and Cy ³ described later.

L ^{2 and} L ³ are each independently a single bond or a divalent linking group. L ² and L ³ are each independently two selected from the group consisting of —O—, —S—, —CO—, —NR ² —, a divalent chain group, a divalent cyclic group, and combinations thereof. A valent linking group or a single bond is preferred. R ² is an alkyl group having 1 to 7 carbon atoms or a hydrogen atom, preferably an alkyl group having 1 to 4 carbon atoms or a hydrogen atom, and is a methyl group, an ethyl group or a hydrogen atom. Is more preferable, and a hydrogen atom is most preferable. The divalent chain group and the divalent cyclic group have the same definitions as L ¹ and L ⁴ .

In the formula (IV), n is 0, 1 or 2. When n is 2, two L ³ may be the same or different, and two Cy ² may be the same or different. n is preferably 1 or 2, and more preferably 1.

In formula (IV), Cy ¹ , Cy ² and Cy ³ are each independently a divalent cyclic group. The ring contained in the cyclic group is preferably a 5-membered ring, a 6-membered ring, or a 7-membered ring, more preferably a 5-membered ring or a 6-membered ring, and most preferably a 6-membered ring. The ring contained in the cyclic group may be a condensed ring. However, it is more preferably a monocycle than a condensed ring. The ring contained in the cyclic group may be any of an aromatic ring, an aliphatic ring, and a heterocyclic ring. Examples of the aromatic ring include a benzene ring and a naphthalene ring. Examples of the aliphatic ring include a cyclohexane ring. Examples of the heterocyclic ring include a pyridine ring and a pyrimidine ring.
As the cyclic group having a benzene ring, 1,4-phenylene is preferable. As the cyclic group having a naphthalene ring, naphthalene-1,5-diyl and naphthalene-2,6-diyl are preferable. The cyclic group having a cyclohexane ring is preferably 1,4-cyclohexylene. As the cyclic group having a pyridine ring, pyridine-2,5-diyl is preferable. The cyclic group having a pyrimidine ring is preferably pyrimidine-2,5-diyl.

  The cyclic group may have a substituent. Examples of the substituent include a halogen atom, a cyano group, a nitro group, an alkyl group having 1 to 5 carbon atoms, a halogen-substituted alkyl group having 1 to 5 carbon atoms, and an alkoxy group having 1 to 5 carbon atoms. , An alkylthio group having 1 to 5 carbon atoms, an acyloxy group having 2 to 6 carbon atoms, an alkoxycarbonyl group having 2 to 6 carbon atoms, a carbamoyl group, and an alkyl-substituted carbamoyl group having 2 to 6 carbon atoms And an acylamino group having 2 to 6 carbon atoms.

  Examples of the polymerizable rod-like liquid crystal compound represented by the formula (IV) are shown below, but are not limited thereto.

-Discotic liquid crystal compounds Discotic liquid crystal compounds can be obtained from various documents (C. Destrade et al., Mol. Crysr. Liq. Cryst., Vol. 71, page 111 (1981); edited by the Chemical Society of Japan). , Quarterly Chemical Review, No. 22, Liquid Crystal Chemistry, Chapter 5, Chapter 10 Section 2 (1994); B. Kohne et al., Angew. Chem. Soc. Chem. Comm., Page 1794 (1985). J. Zhang et al., J. Am.Chem.Soc., Vol.116, page 2655 (1994)). Either can be used in the present invention. Moreover, about superposition | polymerization of a discotic liquid crystalline compound, Unexamined-Japanese-Patent No. 8-27284 has description.

  The discotic liquid crystalline compound preferably has a polymerizable group so that it can be fixed by polymerization. For example, a structure in which a polymerizable group is bonded as a substituent to a discotic core of a discotic liquid crystalline compound is conceivable. However, when a polymerizable group is directly connected to the discotic core, the alignment state is maintained in the polymerization reaction. It becomes difficult. Therefore, a structure having a linking group between the discotic core and the polymerizable group is preferable. That is, the discotic liquid crystalline compound having a polymerizable group is preferably a compound represented by the following formula.

D (-LQ) _n
In the formula, Q is a polymerizable group, and is synonymous with the polymerizable group (Q) in the polyvinyl alcohol having a crosslinkable group in the molecule, and the polymerizable group (Q) in the polymerizable rod-like liquid crystal compound, As described above, it is preferably an unsaturated polymerizable group (the above-described examples Q1 to Q7), an epoxy group (Q8) or an aziridinyl group (Q9), more preferably an unsaturated polymerizable group, and an ethylenic group. Most preferably, it is a saturated polymerizable group (Q1 to Q6).
D is a disk-shaped core, L is a divalent linking group, and n is an integer of 3 to 12. Preferred specific examples of the discotic core (D) and the divalent linking group (L) in the above formula are (D1) to (D15) and (L1) to (D1) described in JP-A No. 2001-4837, respectively. (L25), and the contents described in the publication can be preferably used.

  The above discotic (discotic) compound generally has a structure in which these are used as a mother nucleus at the center of a molecule, and a linear alkyl group, an alkoxy group, a substituted benzoyloxy group, etc. are radially substituted as the linear chain. , Which shows liquid crystallinity and is generally called a discotic liquid crystal. However, the molecule itself is not limited to the above description as long as the molecule itself has negative uniaxiality and can give a certain orientation. Further, in the present invention, it is not necessary that the final product is formed from a discotic compound, for example, the low molecular discotic liquid crystal has a group that reacts with heat, light, or the like. As a result, it may be polymerized or cross-linked by reaction with heat, light, etc., to have a high molecular weight and lose liquid crystallinity.

  Preferred examples of the discotic compound are shown below.

Other components The liquid crystal composition may contain components other than the liquid crystal compound. For example, it may contain a polymerization initiator, an alignment controller, a surfactant and the like as desired.
-Polymerization initiator As the polymerization initiator, any of a thermal polymerization initiator used in a thermal polymerization reaction and a photopolymerization initiator used in a photopolymerization reaction may be used, and a photopolymerization initiator is preferable. Examples of photopolymerization initiators include α-carbonyl compounds (described in US Pat. Nos. 2,367,661 and 2,367,670), acyloin ether (US Pat. No. 2,448,828). ), Α-hydrocarbon substituted aromatic acyloin compounds (described in US Pat. No. 2,722,512), polynuclear quinone compounds (US Pat. Nos. 3,046,127 and 2,951,758) Description), combinations of triarylimidazole dimers and p-aminophenyl ketone (described in US Pat. No. 3,549,367), acridine and phenazine compounds (Japanese Patent Laid-Open No. 60-105667, US Pat. No. 4,239) And oxadiazole compounds (described in U.S. Pat. No. 4,212,970).
The amount of the photopolymerization initiator used is preferably 0.01 to 20% by mass, more preferably 0.5 to 5% by mass based on the liquid crystal composition (solid content in the case of a coating liquid).

-Alignment controller The liquid crystal composition may contain an alignment controller that controls the alignment of the liquid crystal. The alignment control agent can be selected according to the type of liquid crystal, the desired alignment state, and the like.
For example, when the composition contains a rod-like liquid crystal and the rod-like liquid crystal is to be oriented perpendicular to the layer surface (the long axis is perpendicular to the layer surface), it is preferable to contain an onium salt or the like in the composition. . Specific examples are described in JP-A-2006-301605 (Table 1, second phase difference regions 1 to 3) and the like, and any of them can be used.
Further, when the composition contains a rod-like liquid crystal and the rod-like liquid crystal is oriented horizontally with respect to the layer surface (the long axis is parallel to the layer surface), it is preferable to contain a triazine compound or the like in the composition. . Specific examples are described in JP-A-2006-293275 (Example 2) and the like, and any of them can be used.
Further, when the composition contains a discotic liquid crystal and the discotic liquid crystal is oriented perpendicularly to the layer surface (the disk surface is perpendicular to the layer surface), a pyridinium salt (Example 1) in the composition Etc. are preferably contained. Specific examples are described in JP-A-2006-285187 and the like, and any of them can be used.
When the composition contains a discotic liquid crystal and it is desired to align the discotic liquid crystal horizontally to the layer surface (the disk surface is horizontal to the layer surface), a specific fluorine-based polymer or the like is added to the composition. It is preferable to contain. Specific examples are described in JP-A-2006-267183 (Reference Example 2), and any of them can be used.

-Surfactant The liquid crystal composition may contain a surfactant in order to improve applicability. As the surfactant, a fluorine-based surfactant is preferable. Specifically, for example, compounds described in paragraph numbers [0028] to [0056] of JP-A No. 2001-330725 are exemplified.

-Method for forming optically anisotropic layer The optically anisotropic layer is prepared by applying the composition as a coating solution, applied to the surface of the alignment film, dried to remove the solvent, and has a desired alignment state. It is preferable that the alignment state is fixed by polymerization.
As the solvent used for preparing the coating solution, an organic solvent is preferably used. Examples of the organic solvent include amide (eg, N, N-dimethylformamide), sulfoxide (eg, dimethyl sulfoxide), heterocyclic compound (eg, pyridine), hydrocarbon (eg, benzene, hexane), alkyl halide ( Examples, chloroform, dichloromethane), esters (eg, methyl acetate, butyl acetate), ketones (eg, acetone, methyl ethyl ketone), ethers (eg, tetrahydrofuran, 1,2-dimethoxyethane) are included. Alkyl halides and ketones are preferred. Two or more organic solvents may be used in combination. The coating liquid can be applied by a known method (eg, extrusion coating method, direct gravure coating method, reverse gravure coating method, die coating method).

After applying the liquid crystal composition, it is dried to obtain a desired alignment state, and then cured by polymerization to form an optically anisotropic layer. Polymerization is preferably initiated by light irradiation, and ultraviolet light is preferably used for light irradiation. The irradiation energy is preferably 20 mJ / cm ^{2 to} 50 J / cm ² , and more preferably 100 mJ / cm ^{2 to} 800 mJ / cm ² . Furthermore, in order to accelerate the photopolymerization reaction, light irradiation may be performed under heating conditions. In the alignment film of the present invention, since the modified polyvinyl alcohol having a crosslinkable group is unevenly distributed on the air interface side, the alignment film, the optically anisotropic layer, and the It is possible to improve the adhesion. By causing the polymerization reaction to proceed at a relatively low temperature, it is possible to suppress the occurrence of alignment disorder during the progress of the polymerization reaction and stably produce an optically anisotropic layer having desired optical characteristics. In order to sufficiently advance the polymerization reaction without causing alignment disorder, the temperature during light irradiation is preferably about 70 to 100 ° C.

  The thickness of the optically anisotropic layer is preferably 0.1 to 10 μm, more preferably 0.5 to 5 μm, and still more preferably 1 to 5 μm.

The optical film of the present invention can be used for various applications. Especially, it is preferable to utilize as an optical compensation film of a liquid crystal display device. The optical film of the present invention may be used as a single member for a liquid crystal display device or the like, or may be used as one member of a polarizing plate (specifically, a protective film for a polarizing film). Hereinafter, the polarizing plate having the optical film of the present invention will be described.
[Polarizer]
The present invention relates to a polarizing plate having at least the optical film of the present invention and a polarizing film. As an example of the polarizing plate of the present invention, there is a polarizing plate having a polarizing film and protective films on both surfaces thereof, and one of the protective films is the optical film of the present invention. That is, the optical film of the present invention may be bonded as a protective film to one surface of the polarizing film. When the optical film of the present invention is used as a protective film, the back surface of the polymer film (the surface on which the alignment film and the optically anisotropic layer are not formed) is brought into contact with the surface of the polarizing film and laminated. Is preferred.
-Polarizing film The polarizing film includes an iodine polarizing film, a dye polarizing film using a dichroic dye, and a polyene polarizing film, and any of them may be used in the present invention. The iodine polarizing film and the dye polarizing film are generally produced using a polyvinyl alcohol film.

-Protective film It is preferable that a transparent polymer film is used for the protective film bonded to the other surface. “Transparent” means that the light transmittance is 80% or more. As the protective film, a cellulose acylate film and a polyolefin film containing polyolefin are preferable. Among the cellulose acylate films, a cellulose triacetate film is preferable. Of the polyolefin films, a polynorbornene film containing a cyclic polyolefin is preferable.
The thickness of the protective film is preferably 20 to 500 μm, and more preferably 50 to 200 μm.

  The optical film and the polarizing plate of the present invention include various modes of liquid crystal display devices, TN (Twisted Nematic), IPS (In-Plane Switching), OCB (Optically Compensated Bend), VA (Vertically Aligned), ECB (Electrically Cred). And the like can be used for liquid crystal display devices in any display mode. In addition, the liquid crystal display device can be any of a transmissive type, a reflective type, and a transflective type.

  The features of the present invention will be described more specifically with reference to examples and comparative examples. Hereinafter, materials, usage amounts, ratios, processing contents, processing procedures, and the like shown in the examples can be appropriately changed without departing from the gist of the present invention. Therefore, the scope of the present invention should not be construed as being limited by the specific examples shown below.

[Example 1]
First, the present invention will be described using an optical film (optical compensation film) produced by laminating an optically anisotropic layer in which discotic liquid crystal molecules are homeotropically aligned on the alignment film and alignment film of the present invention.
(Production of polymer film)
The following composition was put into a mixing tank and stirred while heating at 30 ° C. to dissolve each component to prepare a cellulose acylate solution (SA-1) (inner layer dope and outer layer dope).
Regarding the silica fine particles of the cellulose acylate solution for the outer layer, 20 parts by mass of the following silica fine particles and 80 parts by mass of methanol were mixed well for 30 minutes to obtain a mixed silica molecular dispersion.

Cellulose acylate (SA-1) solution composition:
Cellulose acylate solution composition (parts by mass) For inner layer For outer layer Cellulose acetate with an acyl substitution degree of 2.87 100 100
Triphenyl phosphate (plasticizer) 7.8 7.8
Biphenyl diphenyl phosphate (plasticizer) 3.9 3.9
Methylene chloride (first solvent) 293 314
Methanol (second solvent) 71 76
1-butanol (third solvent) 1.5 1.6
Silica fine particles (AEROSIL R972, manufactured by Nippon Aerosil Co., Ltd.)
0 0.8
Retardation adjuster A 1.50

The obtained inner layer dope and outer layer dope were cast on a drum cooled to −5 ° C. using a three-layer co-casting die.
The film having a residual solvent amount of 70% by mass was peeled off from the drum, and dried at 80 ° C. while being transported with the draw ratio in the transport direction being 110% while holding both ends with a pin tenter, and the residual solvent amount was 10%. By the way, it was dried at 110 ° C. Thereafter, it was dried at a temperature of 140 ° C. for 30 minutes to prepare a cellulose acylate film (CAF-1, outer layer: 3 μm, inner layer: 74 μm, outer layer: 3 μm) having a residual solvent of 0.3% by mass. The obtained CAF-1 had a width of 1340 mm and a thickness of 80 μm.
The obtained film CAF-1 had an in-plane slow axis in the longitudinal direction, Re (630) was 8 nm, and Rth (630) was 80 nm.

Alkali saponification treatment One side of the film CAF-1 was subjected to the following alkali saponification treatment.
The film (CAF-1) is passed through a dielectric heating roll having a temperature of 60 ° C. and heated to a film surface temperature of 40 ° C., and then an alkali solution (S-1) having the composition shown below is used with a rod coater. It apply | coated with the application quantity of 17 mL / m < ² >, and it was made to retain for 10 second under the steam type far-infrared heater by Noritake Co., Ltd. which was heated to 110 degreeC. Subsequently, using a rod coater as well, “2.8 mL / m ^{2 of} distilled water was applied, and then water washing with a fountain coater and draining with an air knife were repeated three times to wash off the alkali, and then 5 times in a drying zone at 70 ° C. The cellulose acylate film KF-1 in which the film was allowed to stay for 2 seconds and dried to be saponified on one side was produced.

Alkaline solution (S-1) composition:
Potassium hydroxide 8.6 parts by weight Water 24.1 parts by weight Isopropanol 56.3 parts by weight Surfactant (K-1: C ₁₆ H ₃₃ O (CH ₂ CH ₂ O) ₁₀ H) 1.0 part by weight Propylene glycol 10.0 parts by mass

Alkaline solution (S-1) properties:
Surface tension 20mN / m
Viscosity 5.2 mPa · s

  When the contact angle with water was measured on the surface of the saponified cellulose acylate film KF-1, the measurement result at 10 points was in the range of 36 to 38 °.

(Preparation of coating solution for alignment film)
Using the polyvinyl alcohol (PVA) shown in Table 1, various coating solutions for alignment films having the following compositions were prepared. In the composition, the numbers are parts by mass. In addition, the composition amount of the following PVA represents the total amount of unmodified PVA and PVA with a crosslinkable group in Table 1, and the composition ratio of PVA with a crosslinkable group corresponds to the mixing ratio in Table 1.
Composition of coating liquid for alignment film: part by mass PVA 1.244
Glutaraldehyde (50% aqueous solution) 0.12
Citric acid, 1 ethyl citrate, 2 ethyl citrate,
And a mixture of 3 ethyl citrate 0.022
Methanol 9.02
Water 28.794

In Table 1, PVA105, PVA110, and PVA117 are trade names of unmodified PVA manufactured by Kuraray Co., Ltd., and the average polymerization degree and saponification degree are shown in Table 1.
In Table 1, the modified PVA is in accordance with Synthesis Example 1 described in the [0101] column of JP-A-9-152509, but instead of MP203 used (manufactured by Kuraray Co., Ltd.), PVA203, PVA205, This is a modified PVA (modified PVA having a methacryl group as a crosslinkable group) manufactured using PVA210 and PVA103 (manufactured by Kuraray Co., Ltd.).

(Formation of alignment film)
Each of the alignment film coating solutions prepared above was applied to the saponified surface of the saponified cellulose acylate film (KF-1) at a coating amount of 31 mL / m ² and dried at a temperature of 100 ° C. for 2 minutes. Thus, an alignment film was formed on the cellulose acylate film (KF-1), and alignment films were respectively produced.

(Preparation of coating liquid D-1 for optical anisotropy)
――――――――――――――――――――――――――――――――――――
Composition of coating liquid (D-1) containing discotic liquid crystal compound ――――――――――――――――――――――――――――――――――― -
The following discotic liquid crystalline compound (I) 91 parts by mass Ethylene oxide modified trimethylolpropane triacrylate (V # 360, manufactured by Osaka Organic Chemical Co., Ltd.) 9 parts by mass Photopolymerization initiator (Irgacure 907, manufactured by Ciba Geigy) 3 parts by mass Sensitizer (Kayacure DETX, manufactured by Nippon Kayaku Co., Ltd.) 1 part by mass The following fluoropolymer A 0.4 parts by mass Methyl ethyl ketone 212 parts by mass ――――――――――――― ――――――――――――――――――――――

The coating liquid (D-1) containing the discotic liquid crystalline compound having the above composition was continuously applied on the prepared alignment film with a # 6.0 wire bar. The conveyance speed of the film was 20 m / min. The solvent was dried in a step of continuously heating from room temperature to 80 ° C., and then heated in a drying zone at 120 ° C. for 90 seconds to align the discotic liquid crystalline compound. Subsequently, the temperature of the film is maintained at 90 ° C., and UV light is irradiated at 500 mJ / cm ² using a high-pressure mercury lamp, the orientation of the liquid crystal compound is fixed, the optically anisotropic layer B1 is formed, and the optical film F1 -1 was produced.

An optical birefringence meter (KOBRA-21ADH, Oji Scientific Instruments Co., Ltd.) obtained by peeling only the optical anisotropic layer containing the discotic liquid crystalline compound from the optical film F1-1 and the optical film F1-1. The optical properties were measured using Re measured at a wavelength of 590 nm of the optical compensation film F1-1 was 2 nm, and Rth was 280 nm. Further, Re of the optically anisotropic layer alone was 0 nm, and Rth was 200 nm. It was also confirmed that an optically anisotropic layer in which the discotic liquid crystal structural unit was aligned substantially horizontally with respect to the film surface was confirmed.
Further, the film thickness of the optically anisotropic layer was 2.65 μm, and the refractive index anisotropy (Δn = Rth / film thickness of the optically anisotropic layer) was 0.075.

(Preparation of optical films F1-2 to F1-17)
Except for changing the composition of the coating liquid for the alignment film and the liquid crystal layer curing temperature (temperature at the time of UV light irradiation) as shown in Table 1 for the optical film F1-1 produced above, it is the same as F1-1. Optical compensation films F1-2 to F1-17 were prepared.

The optical film produced above was evaluated for water resistance, adhesion, and refractive index anisotropy according to the following methods, and the results are shown in Table 1.
(Evaluation of water resistance of optical film)
The produced optical film sample was immersed in warm water of 40 ° C. for 30 minutes, and then the film was rubbed with a finger to evaluate the adhesion of the film. The evaluation criteria are as follows.
(Double-circle): It does not peel even if it rubs strongly.
◯: Can not be peeled lightly.
Δ: Slightly peeled off when rubbed lightly.
X: Peel off when gently rubbed.

(Adhesion evaluation)
The surface of the optical film sample prepared above having a liquid crystal layer is cut into 11 grids and 11 grids in a grid pattern with a cutter knife to make a total of 100 square grids. ) Made of polyester adhesive tape “No. 31B” was subjected to an adhesion test. The presence or absence of peeling was visually observed, and the following four-stage evaluation was performed.
◎: No peeling was observed in 100 squares ○: No peeling was observed in 100 squares within 2 squares Δ: peeling was observed in 100 squares 3 to 10 mm x: 100 mm of which peeling was observed exceeded 10 mm

(Preparation of polarizing plate)
About the optical films F1-1 to F1-17 produced above, the back surface of the support (the surface on which the alignment film and the optically anisotropic layer are not formed) was saponified. Specifically, it was immersed in a 1.5N sodium hydroxide aqueous solution (55 ° C., 2 minutes) and then washed with water (room temperature, 15 seconds). Further, it was immersed in 0.1N sulfuric acid (30 ° C., 20 seconds) and then washed with water (room temperature, 15 seconds).
Using a polyvinyl alcohol adhesive, the back surface of each optical film subjected to saponification treatment was attached to one surface of the polarizing film with Roll To Roll.
Next, a cellulose triacetate film (TD-80UF: manufactured by Fuji Film Co., Ltd.) having a thickness of 80 μm is subjected to the above saponification treatment, and the surface on the opposite side of the polarizing film is coated with a polyvinyl alcohol adhesive. Affixed with Roll To Roll. In this way, polarizing plates H1-1 to H1-17 were produced.

(Durability evaluation of polarizing plate)
A pressure-sensitive adhesive was applied to the optically anisotropic layer side of each produced polarizing plate, and a sample attached to a glass plate was produced. The sample was allowed to stand in an atmosphere of 65 ° C. and 95% for 6 hours, and then each sample was magnified 30 times with an actual microscope to observe the presence or absence of cracks, and evaluated according to the following criteria.
(Double-circle): A crack is not recognized at all.
○: If you look closely, you can see slight cracks.
Δ: Fine cracks are observed.
X: A crack is clearly visible.
The evaluation results are shown in Table 1 below.

From the evaluation results of the optical film shown in Table 1, the following is clear.
Optical films F1-1 to F1- produced using the alignment film according to the example of the present invention, which contains polyvinyl alcohol having a high saponification degree of 95% or more and a modified polyvinyl alcohol having a methacryl group. No. 12 showed good water resistance and adhesion. In particular, optical films F1-2, F1-3, and F1- produced using alignment films having a high saponified PVA content of 95% by mass or more and an average degree of saponification of the modified PVA of 90% or less. No. 5 was particularly excellent in both water resistance and adhesion.
In addition, since the optical films of the examples cause the polymerization reaction to proceed at a relatively low temperature (90 ° C. or less) during the formation of the optically anisotropic layer, the refraction per film thickness of the formed optically anisotropic layer. The rate anisotropy Δn was sufficiently high.
On the other hand, the comparative optical film F1-13 produced using an alignment film formed using only modified polyvinyl alcohol undergoes a polymerization reaction at a relatively high temperature (110 ° C.) during the formation of the optically anisotropic layer. Therefore, the refractive index anisotropy Δn per film thickness of the formed optically anisotropic layer was lower than that of the example. Like the optical film F1-14, the polymerization reaction during the formation of the optically anisotropic layer proceeds at a relatively low temperature (90 ° C.), thereby reducing the refractive index anisotropy per film thickness of the optically anisotropic layer. Although it could be increased, on the other hand, it can be understood that the water resistance decreases.
Moreover, in the optical films F1-15-F1-17 of the comparative examples produced using the alignment film which does not contain modified polyvinyl alcohol, the adhesion between the optically anisotropic layer and the alignment film is low, and the optical film as a whole It can be understood that the durability of is extremely inferior.

[Example 2]
Next, the present invention will be described using an optical film (optical compensation film) produced by forming an optically anisotropic layer formed by fixing discotic liquid crystal molecules in a hybrid alignment state on the alignment film of the present invention. .

After rubbing the surface of the support with alignment film produced in the same manner as in Example 1, the following coating solution D-2 for optical anisotropy was applied to each rubbing treated surface at 5.3 mL / m ² . Then, the liquid crystal layer was aged at 115 ° C. for 90 seconds to align the liquid crystal layer. Subsequently, UV irradiation was performed after the entire coated product reached 80 ° C., and the liquid crystal layer was fixed in an aligned state to form an optically anisotropic layer. Thus, optical films F2-1 to F2-4 were produced, and water resistance and adhesion were evaluated in the same manner as in Example 1. The results are shown in Table 2 below.

(Preparation of coating liquid D-2 for optical anisotropy)
――――――――――――――――――――――――――――――――――――
Composition of coating liquid (D-2) containing discotic liquid crystal compound ――――――――――――――――――――――――――――――――――― -
9.1 parts by mass of the above discotic liquid crystal compound (I) Ethylene oxide modified trimethylolpropane acrylate (V # 360, trade name, Osaka Organic Chemical Co., Ltd.) 0.9 parts by mass Cellulose acetate butyrate (CAB551-0.2) 0.2 parts by weight Cellulose acetate butyrate (CAB531-1, trade name, manufactured by Eastman Chemical) 0.05 parts by weight The following fluorine compound (F-1) 1.3 parts by weight Irgacure 907 (trade name, manufactured by Ciba Geigy) 3.0 parts by mass Kayacure DETX (trade name, manufactured by Nippon Kayaku Co., Ltd.) 0.1 parts by mass Methyl ethyl ketone 29.6 parts by mass ――――――――― ―――――――――――――――――――――――――――

(Production and evaluation of polarizing plate)
In the same manner as in Example 1, polarizing plates H2-1 to H2-4 each having optical films F2-1 to F2-4 attached as protective films were prepared, and in the same manner as in Example 1, polarizing plates were prepared. The durability was evaluated. The evaluation results are shown in Table 2 below.

  From the results of Table 2, when the alignment film which is an embodiment of the present invention is used, the same applies to an optical film having an optically anisotropic layer formed by fixing a discotic hybrid alignment state and a polarizing plate using the optical film. It can be understood that the effect is obtained.

[Example 3]
(Production and evaluation of optical film)
A coating liquid containing a rod-like liquid crystal compound described in JP-A-2006-215092 [0198] to [0200], that is, a coating liquid N-1 having the following composition was prepared.
Composition of coating liquid N-1:
The following rod-shaped liquid crystal compound A 3.8 g
Photopolymerization initiator (Irgacure 907, manufactured by Ciba Geigy) 0.06 g
Sensitizer (Kayacure DETX, manufactured by Nippon Kayaku Co., Ltd.) 0.02g
The following air interface side vertical alignment agent 0.002g
9.2 g of methyl ethyl ketone

This coating solution N-1 was applied to the support with an alignment film shown in Table 1 below prepared in Example 1 with a wire bar of # 4.5. This was affixed to a metal frame and heated in a constant temperature bath at 100 ° C. for 2 minutes to align the rod-like liquid crystal compound. Next, UV irradiation was performed at 80 ° C. with a 120 W / cm high-pressure mercury lamp for 20 seconds to crosslink the rod-like liquid crystal compound, and then allowed to cool to room temperature to form an optically anisotropic layer. F3-4 was prepared.
The water resistance and adhesion of optical films F2-1 to F2-4 produced in the same manner as in Example 1 were evaluated. The results are shown in Table 3 below.

(Production and evaluation of polarizing plate)
Polarizing plates H3-1 to H3-4 each having optical films F3-1 to F3-4 attached as protective films were produced in the same manner as in Example 1, and polarizing plates were obtained in the same manner as in Example 1. The durability was evaluated. The evaluation results are shown in Table 3 below.

  From the results of Table 3, when using the alignment film according to the embodiment of the present invention, an optical film having an optically anisotropic layer formed by fixing the homeotropic alignment state of the rod-like liquid crystal, and a polarizing plate using the same, It turned out that the same effect is acquired.

Claims (19)

An alignment film comprising polyvinyl alcohol as a main component, comprising at least one polyvinyl alcohol having an average saponification degree of 95% or higher and at least one modified polyvinyl alcohol having a crosslinkable group in the molecule; An alignment film, wherein the content of the modified polyvinyl alcohol is less than that of the high saponification degree polyvinyl alcohol. The alignment film according to claim 1 or 2, wherein an average saponification degree of the modified polyvinyl alcohol is 95% or less. The alignment film according to claim 1 or 2, wherein an average saponification degree of the modified polyvinyl alcohol is 70 to 90%. The alignment film according to any one of claims 1 to 3, wherein the crosslinkable group of the modified polyvinyl alcohol is any one of an unsaturated polymerizable group, an epoxy group, and an aziridinyl group. The alignment film according to any one of claims 1 to 4, wherein the crosslinkable group of the modified polyvinyl alcohol is an ethylenically unsaturated polymerizable group. 6. The alignment film according to claim 1, wherein the ratio of the high saponification degree polyvinyl alcohol is 85% by mass or more based on the total mass of all the polyvinyl alcohols contained. The orientation film according to any one of claims 1 to 6, wherein a ratio of the high saponification degree polyvinyl alcohol is 90% by mass or more based on a total mass of all the polyvinyl alcohols contained. 8. The alignment film according to claim 1, wherein the ratio of the high saponification degree polyvinyl alcohol is 95% by mass or more based on the total mass of all the polyvinyl alcohols contained. The alignment film according to claim 1, wherein the average degree of polymerization of the high saponification degree polyvinyl alcohol is 800 or more. The alignment film according to any one of claims 1 to 9, wherein the average degree of polymerization of the modified polyvinyl alcohol is 800 or less. The orientation film which has a polymer film and the orientation film of any one of Claims 1-10 on it. The oriented film according to claim 11, wherein the polymer film is a polymer film containing cellulose acylate as a main component. 13. An optical film comprising the alignment film according to claim 11 or 12, and an optically anisotropic layer formed from a liquid crystal composition on the alignment film. 14. The optical film according to claim 13, wherein the optically anisotropic layer is a layer formed by curing a curable liquid crystal composition containing a liquid crystal compound having a crosslinkable group in an aligned state. . The optical film according to claim 14, wherein the crosslinkable group of the liquid crystalline compound is the same type of crosslinkable group as the crosslinkable group of the modified polyvinyl alcohol contained in the alignment film. The optical film according to claim 15, wherein the crosslinkable group is an ethylenically unsaturated polymerizable group. A polarizing plate comprising at least a polarizing film and the optical film according to claim 1. The polarizing plate according to claim 17, wherein the optical film is a protective film for the polarizing film. A liquid crystal display device comprising the polarizing plate according to claim 17 or 18.