阅读说明：本技术 层叠体及其制法、光学膜的形成方法、偏光膜及其制法、圆偏光板、液晶显示元件的制法 (Laminate and method for producing same, method for forming optical film, polarizing film and method for producing same, circularly polarizing plate, and method for producing liquid crystal display ele) 是由 樫下幸志 大场佑树 绫部真嗣 栗田慎也 于 2020-03-16 设计创作，主要内容包括：本发明提供一种层叠体及其制法、光学膜的形成方法、偏光膜及其制法、圆偏光板、液晶显示元件的制法。本发明的课题为获得具有光学功能的转印膜与液晶取向膜的剥离性良好、且转印后的表面粗糙度小、液晶取向性良好的转印膜。层叠体包括：支撑体、形成于支撑体上的液晶取向膜、以及形成于液晶取向膜上的光学膜。液晶取向膜是使用液晶取向剂而形成,所述液晶取向剂含有：第一聚合物,为选自由聚酰胺酸、聚酰亚胺及聚酰胺酸酯所组成的群组中的至少一种聚合物且具有光取向性基；以及第二聚合物,为具有与聚酰胺酸、聚酰亚胺及聚酰胺酸酯不同的主链的聚合物且具有光取向性基。光学膜是使液晶组合物硬化而获得。(The invention provides a laminate and a method for producing the same, a method for forming an optical film, a polarizing film and a method for producing the same, a circularly polarizing plate, and a method for producing a liquid crystal display element. The invention aims to obtain a transfer film with good stripping performance between the transfer film with optical function and a liquid crystal orientation film, small surface roughness after transfer and good liquid crystal orientation. The laminate includes: the liquid crystal display device includes a support, a liquid crystal alignment film formed on the support, and an optical film formed on the liquid crystal alignment film. The liquid crystal alignment film is formed by using a liquid crystal alignment agent, and the liquid crystal alignment agent contains: a first polymer which is at least one polymer selected from the group consisting of polyamic acid, polyimide and polyamic acid ester and has a photo-alignment group; and a second polymer having a main chain different from the polyamic acid, the polyimide, and the polyamic acid ester, and having a photo-alignment group. The optical film is obtained by hardening the liquid crystal composition.)

1. A laminate comprising a support, a liquid crystal alignment film formed on the support, and an optical film formed on the liquid crystal alignment film, wherein

The liquid crystal alignment film is formed by using a liquid crystal alignment agent, and the liquid crystal alignment agent contains: a first polymer which is at least one polymer selected from the group consisting of polyamic acid, polyimide and polyamic acid ester and has a photo-alignment group; and a second polymer having a main chain different from that of the polyamic acid, the polyimide, and the polyamic acid ester and having a photo-alignment group,

the optical film is obtained by hardening a liquid crystal composition.

2. The laminate according to claim 1, wherein the laminate is a laminate for forming an optical film layer on an adherend by transferring the optical film of the laminate to the adherend.

3. The laminate according to claim 1 or 2, wherein the liquid crystal aligning agent contains a polymer having a photo-aligning group in a main chain as the first polymer.

4. The laminate according to claim 1 or 2, wherein the liquid crystal aligning agent contains a polymer having a cinnamic acid structure in a main chain as the first polymer.

5. A method for producing a laminate having a support, a liquid crystal alignment film formed on the support, and an optical film formed on the liquid crystal alignment film, the method comprising:

a step of applying a liquid crystal aligning agent onto the support to form a coating film, the liquid crystal aligning agent comprising: a first polymer which is at least one polymer selected from the group consisting of polyamic acid, polyimide and polyamic acid ester and has a photo-alignment group; and a second polymer having a main chain different from the polyamic acid, the polyimide, and the polyamic acid ester, and having a photo-alignment group;

a step of forming a liquid crystal alignment film on the support by imparting liquid crystal alignment ability to the coating film; and

and forming the optical film on the liquid crystal alignment film.

6. A method of forming an optical film, which is a method of forming an optical film on an adherend, and includes:

a step of transferring the optical film of the laminate according to any one of claims 1 to 4 to the adherend.

7. A method for producing a polarizing film with a phase difference film, which is a method for producing a polarizing film with a phase difference film, and which comprises:

a step of transferring the optical film of the laminate according to any one of claims 1 to 4 to a polarizing film.

8. A polarizing film with a phase difference film, which is obtained by transferring the optical film of the laminate according to any one of claims 1 to 4 onto a polarizing film.

9. A circularly polarizing plate comprising a retardation layer, a resin layer, a liquid crystal alignment film, and a polarizing layer laminated in this order

The phase difference layer and the polarizing layer are formed by hardening a liquid crystal composition,

the liquid crystal alignment film is formed by using a liquid crystal alignment agent, and the liquid crystal alignment agent contains a polymer with a photo-alignment group.

10. A method of manufacturing a liquid crystal display element, which is a method of manufacturing a liquid crystal display element, and includes:

a step of constructing a liquid crystal cell having a pair of substrates arranged to face each other and a liquid crystal layer provided between the pair of substrates; and

a step of transferring the optical film of the laminate according to any one of claims 1 to 4 to the outside of at least one of the pair of substrates of the liquid crystal cell.

Technical Field

The present invention relates to a laminate, a method for producing an optical film, a polarizing film and a method for producing the same, a circularly polarizing plate, and a method for producing a liquid crystal display element, and more particularly to a technique for transferring an optical film to an adherend to impart an optical function to the adherend.

Background

Various optical materials are used for liquid crystal display devices such as liquid crystal displays. As the optical material, for example, an optical compensation film such as a retardation film, a viewing angle compensation film, and an antireflection film is known. Of these, for example, a retardation film is used for the purpose of eliminating coloring of display or eliminating viewing angle dependence of display color and contrast ratio which change depending on the visual direction. As the retardation film, a film obtained by stretching a plastic film, a film obtained by applying a liquid crystal coating technique, or the like is known.

In order to further improve the display quality of a liquid crystal display or the like, various retardation films have been proposed (for example, see patent document 1 or patent document 2). Patent documents 1 and 2 disclose: only one of the liquid crystal alignment film and the optically anisotropic film formed on the plastic film is transferred to a substrate of a liquid crystal display device or a polarizing plate, and the transfer film is attached, thereby imparting a desired function to the adherend.

[ Prior art documents ]

[ patent document ]

[ patent document 1] Japanese patent No. 5363022 publication

[ patent document 2] International publication No. 2016/158298

Disclosure of Invention

[ problems to be solved by the invention ]

When an optical function is imparted to an adherend by a transfer film, if the transfer film is less likely to peel off from the liquid crystal alignment film, the transfer film may be in the following state: after the transfer film is transferred to the adherend, the liquid crystal alignment film is locally attached to the transfer film. In this case, there is a possibility that a sufficient optical function cannot be imparted to the adherend. In addition, in the case of using the transfer film for display devices, in order to sufficiently obtain an optical compensation effect and the like by the transfer film, the transfer film is required to be easily peeled off from the liquid crystal alignment film, and the transfer film after transfer has a small surface roughness and good liquid crystal alignment properties.

An object of the present invention is to provide a liquid crystal aligning agent for forming a liquid crystal alignment film that can obtain a transfer film having an optical function, which has good peeling properties from the liquid crystal alignment film, and which has low surface roughness after transfer and good liquid crystal alignment properties.

[ means for solving problems ]

The present invention adopts the following means to solve the above problems.

< 1 > a laminate which has a support, a liquid crystal alignment film formed on the support, and an optical film formed on the liquid crystal alignment film, and which is formed using a liquid crystal alignment agent containing: a first polymer which is at least one polymer selected from the group consisting of polyamic acid, polyimide and polyamic acid ester and has a photo-alignment group; and a second polymer having a main chain different from that of the polyamic acid, the polyimide, and the polyamic acid ester and having a photo-alignment group, wherein the optical film is obtained by curing the liquid crystal composition.

< 2 > the laminate according to the < 1 > wherein the laminate is for forming an optical film layer on an adherend by transferring the optical film possessed by the laminate to the adherend.

< 3 > the laminate according to < 1 > wherein said liquid crystal aligning agent contains a polymer having a photo-aligning group in the main chain as said first polymer.

< 4 > the laminate according to any one of said < 1 > to < 3 >, wherein said liquid crystal aligning agent contains a polymer having a cinnamic acid structure in a main chain as said first polymer.

< 5 > a method for producing a laminate having a support, a liquid crystal alignment film formed on the support, and an optical film formed on the liquid crystal alignment film, comprising: a step of applying a liquid crystal aligning agent onto the support to form a coating film, the liquid crystal aligning agent comprising: a first polymer which is at least one polymer selected from the group consisting of polyamic acid, polyimide and polyamic acid ester and has a photo-alignment group; and a second polymer having a main chain different from the polyamic acid, the polyimide, and the polyamic acid ester, and having a photo-alignment group; a step of forming a liquid crystal alignment film on the support by imparting liquid crystal alignment ability to the coating film; and a step of forming the optical film on the liquid crystal alignment film.

< 6 > a method of forming an optical film, which is a method of forming an optical film on an adherend, and which comprises: and a step of transferring the optical film of the laminate according to any one of the above-mentioned < 1 > to < 4 > onto the adherend.

< 7 > a method for producing a polarizing film with a phase difference film, which is a method for producing a polarizing film with a phase difference film, and comprises: and a step of transferring the optical film of the laminate according to any one of the above-mentioned < 1 > to < 4 > onto a polarizing film.

< 8 > a polarizing film with a phase difference film, which is obtained by transferring an optical film of the laminate according to any one of the < 1 > to < 4 > onto a polarizing film.

< 9 > a circularly polarizing plate comprising a retardation layer, a resin layer, a liquid crystal alignment film and a polarizing layer laminated in this order, wherein the retardation layer and the polarizing layer are each formed by curing a liquid crystal composition, the liquid crystal alignment film is formed using a liquid crystal aligning agent containing a polymer having a photo-alignment group.

< 10 > a method for manufacturing a liquid crystal display element, which is a method for manufacturing a liquid crystal display element, and comprises: a step of constructing a liquid crystal cell having a pair of substrates arranged to face each other and a liquid crystal layer provided between the pair of substrates; and a step of transferring the optical film of the laminate according to any one of the < 1 > to < 4 > to the outside of at least one of the pair of substrates of the liquid crystal cell.

[ Effect of the invention ]

According to the laminate of the present invention, an optical film having good liquid crystal alignment properties and excellent surface roughness of a liquid crystal film can be formed on a substrate. Therefore, the optical film formed on the adherend using the laminate of the present invention can be suitably used in the field of image display and the like because of its high effect of improving the display quality of the liquid crystal display element. In addition, according to the liquid crystal aligning agent of the present invention, the following liquid crystal alignment film can be formed: the transfer film has good peelability with an optical film (transfer film) having an optical function, and can obtain a liquid crystal film having excellent surface roughness after peeling.

Drawings

Fig. 1 (a) to (c) are schematic views showing a method of forming an optical film.

Fig. 2 is a schematic configuration diagram of a circular polarizing plate.

[ description of symbols ]

10: laminated body

11: support body

12: liquid crystal alignment film

13: optical film

21: adherend

22: adhesive layer

23: transfer printing film

30: circular polarizing plate

31: base material

32: first alignment film

33: retardation layer

34: resin layer

35: second alignment film

36: and a polarizing layer.

Detailed Description

EXAMPLE 1 embodiment

Hereinafter, the present embodiment will be described with reference to the drawings as appropriate. As shown in fig. 1 (a) to (c), one embodiment is a laminate 10 in which a support 11, a liquid crystal alignment film 12, and an optical film 13 are laminated in this order. The liquid crystal alignment film 12 is formed using a liquid crystal aligning agent. The liquid crystal aligning agent is used as follows: the liquid crystal alignment film 12 for obtaining the adherend 21 having the optical film 13 is formed by transferring the optical film 13 from the laminate 10 onto a substrate (adherend 21) different from the support 11. The optical film 13 corresponds to a "transfer film".

The liquid crystal aligning agent contains: a first polymer [ A ] which is at least one polymer selected from the group consisting of polyamic acid, polyimide, and polyamic acid ester and has a photo-alignment group; and a second polymer [ B ] which is a polymer having a main chain different from that of the polyamic acid, the polyimide, and the polyamic acid ester and has a photo-alignment group. Hereinafter, components to be blended in the liquid crystal aligning agent and other components optionally blended as necessary will be described.

< liquid Crystal Aligning agent >

First Polymer [ A ]

The photo-alignment group of the first polymer [ a ] is a functional group that imparts anisotropy to the film by photoisomerization reaction, photodimerization reaction, photodecomposition reaction, photo Fries rearrangement (photo Fries rearrangement) reaction, or the like by light irradiation. Specific examples of the photo-alignment group include: an azobenzene-containing group containing azobenzene or a derivative thereof as a basic skeleton, a cinnamic acid structure-containing group containing cinnamic acid or a derivative thereof as a basic skeleton, a chalcone-containing group containing chalcone or a derivative thereof as a basic skeleton, a benzophenone-containing group containing benzophenone or a derivative thereof as a basic skeleton, a coumarin-containing group containing coumarin or a derivative thereof as a basic skeleton, and the like. Of these, the photo-alignment group of the first polymer [ a ] is preferably one selected from the group consisting of an azobenzene-containing group and a cinnamic acid structure-containing group. In particular, a group having a cinnamic acid structure is preferable in terms of having a high orientation ability and being easily introduced into a polymer, and specifically, a group represented by the following formula (1) is preferable.

[ solution 1]

(in the formula (1), R¹And R²Each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms or a cyano group; r³Halogen atom, alkyl group having 1 to 3 carbon atoms, alkoxy group having 1 to 3 carbon atoms or cyano group; a is an integer of 0-4; wherein, when a is 2 or more, a plurality of R³May be the same or different; x¹Is an oxygen atom, a sulfur atom or-NR⁸- (wherein, R)⁸Is a hydrogen atom or a monovalent organic group); "+" indicates a bond)

Examples of the group represented by the formula (1) include: a monovalent group obtained by removing one hydrogen atom of a carboxyl group of cinnamic acid or an aminocarbonyl group of cinnamamide, a group obtained by introducing a substituent to a benzene ring of the monovalent group (hereinafter, these groups are also referred to as "cis-cinnamate groups"), a monovalent group obtained by esterifying a carboxyl group of cinnamic acid or an aminocarbonyl group of cinnamamide and bonding a divalent organic group to a benzene ring, a group obtained by introducing a substituent to a benzene ring of the monovalent group (hereinafter, these groups are also referred to as "trans-cinnamate groups"), or the like.

At X¹is-NR⁸In the case of-R⁸Preferably a hydrogen atom, a C1-6 monovalent hydrocarbon group or a t-butoxycarbonyl group. a is preferably 0 or 1.

The cis-cinnamate group can be represented by, for example, the following formula (cn-1), and the trans-cinnamate group can be represented by, for example, the following formula (cn-2).

[ solution 2]

(in the formula (cn-1), R⁴Hydrogen atom, halogen atom, alkyl group having 1 to 3 carbon atoms, alkoxy group having 1 to 3 carbon atoms or cyano group; r⁵A phenylene group, a biphenylene group, a cyclohexylene group, or a group in which at least a part of hydrogen atoms of these groups is substituted with a halogen atom, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, or a monovalent group in which at least a part of hydrogen atoms of the alkoxy group is substituted with a halogen atom, or a cyano group; a. the¹Is a single bond, an oxygen atom, a sulfur atom, an alkanediyl group having 1 to 3 carbon atoms, -CH ═ CH-, -NH-, "C¹-COO-、*¹-OCO-、*¹-NH-CO-、*¹-CO-NH-、*¹-CH₂-O-or¹-O-CH₂-(“*¹"represents and R⁵A bond of (c); b is 0 or 1;

in the formula (cn-2), R⁶An alkyl group having 1 to 3 carbon atoms; a. the²Is an oxygen atom²-COO-、*²-OCO-、*²-NH-CO-or²-CO-NH-(“*²"represents and R⁷A bond of (c); r⁷An alkanediyl group having 1 to 6 carbon atoms; c is 0 or 1;

r in the formulae (cn-1) and (cn-2)¹、R²、R³、X¹And a has the same meaning as described for formula (1); "+" indicates a bond)

The content ratio of the photo-alignment group in the first polymer [ a ] is preferably 1 to 70 mol%, more preferably 3 to 60 mol%, and still more preferably 5 to 60 mol% with respect to the total amount of monomers used for synthesizing the first polymer [ a ].

(Polyamic acid)

The polyamic acid as the first polymer [ a ] is preferably a polyamic acid having a photo-alignment group in a main chain. The polyamic acid can be obtained by reacting tetracarboxylic dianhydride with a diamine compound, for example. The polyamic acid as the first polymer [ a ] is preferably a polymer obtained by polymerization using a diamine having a photoreactive group in the main chain (hereinafter, also referred to as "specific diamine"), in terms of high freedom of selection of monomers. The tetracarboxylic dianhydride used for the synthesis of the polyamic acid is not particularly limited, and various conventionally known tetracarboxylic dianhydrides such as the tetracarboxylic dianhydride described in japanese patent application laid-open No. 2010-97188 can be used.

As the specific diamine, an aromatic diamine represented by the following formula (2) can be preferably used.

[ solution 3]

(in the formula (2), X²And X³Each independently is a single bond or a divalent linking group, Y¹Is a divalent group represented by the formula (1); a1 is 0 or 1; wherein, when a1 is 0, X²Is a single bond, and the primary amino group in the formula (2) is bonded to the benzene ring in the formula (1)

Specific examples of the specific diamine include compounds represented by the following formulae. Further, the specific diamine may be used alone or in combination of two or more.

[ solution 4]

In the synthesis of the polyamic acid, a diamine other than the specific diamine may be used in combination. The other diamine is not particularly limited, and a conventionally known diamine compound such as the diamine described in Japanese patent application laid-open No. 2010-97188 can be used. When other diamines are used in combination, the proportion of the specific diamine to be used is preferably 10 mol% or more, more preferably 30 mol% or more, based on the total amount of the diamine compounds used in the synthesis. One diamine may be used alone, or two or more diamines may be used.

The synthesis reaction of the polyamic acid is preferably carried out in an organic solvent. The reaction temperature in this case is preferably-20 ℃ to 150 ℃ and the reaction time is preferably 0.1 hour to 24 hours. Examples of the organic solvent used in the reaction include: aprotic polar solvents, phenolic solvents, alcohols, ketones, esters, ethers, halogenated hydrocarbons, and the like. The amount of the organic solvent used is preferably such that the total amount of the tetracarboxylic dianhydride and the diamine compound is 0.1 to 50 mass% relative to the total amount of the reaction solution.

(polyimide)

In the case where the first polymer [ a ] is a polyimide, the polyimide can be obtained by: the polyamic acid synthesized in the manner described is subjected to dehydration ring closure and imidization.

The polyimide may be a complete imide compound obtained by dehydration ring closure of the whole amic acid structure of the polyamic acid as a precursor thereof, or may be a partial imide compound obtained by dehydration ring closure of only a part of the amic acid structure and coexistence of the amic acid structure and the imide ring structure. The imidization ratio of the polyimide is preferably 30% or more, more preferably 40% to 99%, and still more preferably 50% to 99%. The imidization ratio is a ratio of the number of imide ring structures to the total of the number of amic acid structures and the number of imide ring structures of the polyimide expressed as a percentage. Here, a part of the imide ring may be an imide ring.

The dehydration ring-closing of the polyamic acid is preferably carried out by the following method: a method of heating the polyamic acid; or a method in which the polyamic acid is dissolved in an organic solvent, and a dehydrating agent and a dehydration ring-closing catalyst are added to the solution, and heating is carried out as necessary. Among them, the method described later is preferably used.

In the method of adding a dehydrating agent and a dehydration ring-closure catalyst to a solution of polyamic acid, an acid anhydride such as acetic anhydride, propionic anhydride, or trifluoroacetic anhydride may be used as the dehydrating agent. The amount of the dehydrating agent to be used is preferably 0.01 to 20 moles based on 1 mole of the amic acid structure of the polyamic acid. As the dehydration ring-closure catalyst, for example, pyridine, collidine, lutidine, triethylamine and other tertiary amines can be used. The amount of the dehydration ring-closing catalyst to be used is preferably 0.01 to 10 mol based on 1 mol of the dehydrating agent to be used. Examples of the organic solvent used in the dehydration ring-closure reaction include organic solvents exemplified as organic solvents used in the synthesis of polyamic acid. The reaction temperature of the dehydration ring-closure reaction is preferably 0 to 180 ℃, more preferably 10 to 150 ℃. The reaction time is preferably 1.0 to 120 hours, more preferably 2.0 to 30 hours.

Thus, a reaction solution containing polyimide can be obtained. The reaction solution may be directly supplied to the preparation of the liquid crystal aligning agent, may be supplied to the preparation of the liquid crystal aligning agent after removing the dehydrating agent and the dehydration ring-closing catalyst from the reaction solution, may be supplied to the preparation of the liquid crystal aligning agent after separating the polyimide, or may be supplied to the preparation of the liquid crystal aligning agent after refining the separated polyimide. These purification operations may be carried out according to known methods. Further, the polyimide may also be obtained by imidization of a polyamic acid ester.

(polyamic acid ester)

In the case where the first polymer [ a ] is a polyamic acid ester, the polyamic acid ester can be obtained, for example, by the following method or the like: [I] a method of reacting a polyamic acid obtained by the synthesis reaction with an esterifying agent; [ II ] a method for reacting a tetracarboxylic acid diester with a diamine; [ III ] A process for reacting a tetracarboxylic acid diester dihalide with a diamine.

In the present specification, the term "tetracarboxylic diester" refers to a compound in which 2 of 4 carboxyl groups of a tetracarboxylic acid are esterified and the remaining 2 are carboxyl groups. The "tetracarboxylic acid diester dihalide" refers to a compound in which 2 of 4 carboxyl groups of a tetracarboxylic acid are esterified and the remaining 2 are halogenated.

Examples of the esterification agent used in the process [ I ] include: hydroxyl group-containing compounds, acetal compounds, halides, epoxy group-containing compounds, and the like. Specific examples of these include the hydroxyl group-containing compounds: alcohols such as methanol, ethanol and propanol, phenols such as phenol and cresol; examples of the acetal compound include: n, N-dimethylformamide diethylacetal, N-diethylformamide diethylacetal, and the like; examples of the halide include: methyl bromide, ethyl bromide, octadecyl bromide, methyl chloride, octadecyl chloride, 1,1, 1-trifluoro-2-iodoethane, etc.; examples of the epoxy group-containing compound include: propylene oxide, and the like.

The tetracarboxylic acid diester used in the process [ II ] can be obtained, for example, by: the tetracarboxylic dianhydride exemplified in the synthesis of the polyamic acid is subjected to ring opening using an alcohol such as methanol or ethanol. In the method [ II ], as the acid derivative, only a tetracarboxylic acid diester may be used, or a tetracarboxylic acid dianhydride may be used in combination. The diamine used may be the one exemplified in the synthesis of polyamic acid.

The reaction of the process [ II ] is preferably carried out in an organic solvent in the presence of a suitable dehydration catalyst. The organic solvent may be an organic solvent exemplified as an organic solvent used for synthesis of a polyamic acid. Examples of the dehydration catalyst include: 4- (4, 6-dimethoxy-1, 3, 5-triazin-2-yl) -4-methylmorpholinium halide, carbonylimidazole, phosphorus-based condensing agent, and the like. The reaction temperature in this case is preferably-20 to 150 ℃ and more preferably 0 to 100 ℃. The reaction time is preferably 0.1 to 24 hours, more preferably 0.5 to 12 hours.

The tetracarboxylic acid diester dihalide used in the process [ III ] can be obtained, for example, by: the tetracarboxylic acid diester obtained in the above manner is reacted with an appropriate chlorinating agent such as thionyl chloride. In the method [ III ], as the acid derivative, only a tetracarboxylic acid diester dihalide may be used, or a tetracarboxylic acid dianhydride may be used in combination. The diamine used may be the one exemplified in the synthesis of polyamic acid.

The reaction of the process [ III ] is preferably carried out in an organic solvent in the presence of an appropriate base. The organic solvent may be an organic solvent exemplified as an organic solvent used for synthesis of a polyamic acid. As the base, for example, there can be preferably used: tertiary amines such as pyridine and triethylamine; alkali metals such as sodium hydride, potassium hydride, sodium hydroxide, potassium hydroxide, sodium and potassium, and the like. The reaction temperature in this case is preferably-20 to 150 ℃ and more preferably 0 to 100 ℃. The reaction time is preferably 0.1 to 24 hours, more preferably 0.5 to 12 hours.

The polyamic acid ester contained in the liquid crystal aligning agent may have only an amic acid ester structure or may be a partially esterified product in which an amic acid structure and an amic acid ester structure coexist. The reaction solution in which the polyamic acid ester is dissolved may be supplied as it is to the production of the liquid crystal aligning agent, or the polyamic acid ester contained in the reaction solution may be separated and supplied to the production of the liquid crystal aligning agent, or the separated polyamic acid ester may be purified and supplied to the production of the liquid crystal aligning agent. The isolation and purification of the polyamic acid ester can be carried out according to a known method.

(solution viscosity and weight-average molecular weight)

The polyamic acid, polyamic acid ester, and polyimide obtained in the above-described manner preferably exhibit a solution viscosity of 10 to 800mPa · s, more preferably 15 to 500mPa · s, when the polyamic acid, polyamic acid ester, and polyimide are prepared into a solution having a concentration of 10% by mass. The solution viscosity (mPa · s) of the polymer is a value measured at 25 ℃ using an E-type rotational viscometer for a polymer solution having a concentration of 10 mass% prepared using a good solvent for the polymer (e.g., γ -butyrolactone, N-methyl-2-pyrrolidone, etc.).

The weight average molecular weight (Mw) of the polyamic acid, polyamic acid ester, and polyimide obtained in the above manner, as measured by Gel Permeation Chromatography (GPC) in terms of polystyrene, is preferably 1,000 to 500,000, more preferably 2,000 to 300,000. The molecular weight distribution (Mw/Mn) is preferably 7 or less, more preferably 5 or less.

Second Polymer [ B ]

The photo-alignment group of the second polymer [ B ] may be the same as a specific example of the photo-alignment group of the first polymer. In particular, a group having a cinnamic acid structure is preferable in terms of having a high orientation ability and being easily introduced into a polymer.

The second polymer [ B ] is not limited as long as it is a polymer different from the polyamic acid, the polyimide, and the polyamic acid ester, and is preferably at least one selected from the group consisting of a polyorganosiloxane, a styrene-maleimide copolymer, and a (meth) acrylic polymer. Hereinafter, the polyorganosiloxane, the styrene-maleimide copolymer, and the (meth) acrylic polymer will be described separately.

(polyorganosiloxane)

When the second polymer [ B ] is a polyorganosiloxane having photo-alignment groups (hereinafter, also referred to as "polyorganosiloxane [ a"), the method for synthesizing the polyorganosiloxane [ a ] is not particularly limited, and the following method is preferably used in terms of simplicity and improvement of the introduction rate of the photo-alignment groups: the epoxy group-containing polyorganosiloxane is obtained by hydrolytic condensation of an epoxy group-containing alkoxysilane or a mixture of an epoxy group-containing alkoxysilane and another silane compound, and then the obtained epoxy group-containing polyorganosiloxane is reacted with a carboxylic acid having a photo-alignment group (hereinafter, also referred to as "specific carboxylic acid").

The epoxy group-containing polyorganosiloxane can be obtained by, for example, hydrolyzing and condensing a hydrolyzable silane compound. The silane compound to be used is not particularly limited as long as it exhibits hydrolyzability, and examples thereof include: tetraalkoxysilane, phenyltrialkoxysilane, dialkyldialkoxysilane, monoalkyltrialkoxysilane, mercaptoalkyltrialkoxysilane, ureidoalkyltrialkoxysilane, aminoalkyltrialkoxysilane, 3-glycidoxypropyltrialkoxysilane, 2- (3, 4-epoxycyclohexyl) ethyltrialkoxysilane, 3- (3, 4-epoxycyclohexyl) propyltrialkoxysilane, 3- (meth) acryloyloxypropyltrialkoxysilane, vinyltrialkoxysilane, p-styryltrialkoxysilane, trimethoxysilylpropylsuccinic anhydride, and the like. The silane compound may be used singly or in combination of two or more of these.

The hydrolysis and condensation reaction of the silane compound is carried out as follows: one or more silane compounds described above are reacted with water, preferably in the presence of a suitable catalyst and an organic solvent. In the hydrolysis and condensation reaction, the proportion of water used is preferably 1 to 30 moles per 1 mole of the silane compound (total amount). Examples of the catalyst include: acids, alkali metal compounds, organic bases, titanium compounds, zirconium compounds, and the like. The amount of the catalyst to be used varies depending on the kind of the catalyst, reaction conditions such as temperature, and the like, and is suitably set, for example, preferably from 0.05 to 1 times by mole based on the total amount of the silane compounds. Examples of the organic solvent used in the reaction include: hydrocarbons, ketones, esters, ethers, alcohols, and the like. Among these, it is preferable to use an organic solvent which is not water-soluble or hardly water-soluble. The use ratio of the organic solvent is preferably 10 to 1,000 parts by mass with respect to 100 parts by mass of the total of the silane compounds used in the reaction.

The hydrolysis and condensation reaction are preferably carried out by heating (for example, to 40 to 130 ℃) with an oil bath or the like. The heating time is preferably 0.5 to 8 hours. After the reaction is completed, the organic solvent layer separated from the reaction solution is washed with water as necessary, and the organic solvent layer is dried with a drying agent, and then the solvent is removed, whereby the target polyorganosiloxane can be obtained. The method for synthesizing the polyorganosiloxane is not limited to the hydrolysis and condensation reaction, and may be carried out, for example, by reacting a hydrolyzable silane compound in the presence of oxalic acid and an alcohol.

Subsequently, the obtained polyorganosiloxane containing an epoxy group is reacted with a specific carboxylic acid. Thus, the epoxy group of the epoxy group-containing polyorganosiloxane is reacted with a carboxylic acid to obtain polyorganosiloxane [ A ].

The specific carboxylic acid is not particularly limited as long as it has a photo-alignment group, and is preferably a carboxylic acid having a group containing a cinnamic acid structure. Examples of such specific carboxylic acids include X in the groups represented by the above formula (cn-1) and the above formula (cn-2)¹And carboxylic acids in which hydrogen atoms are bonded to a part of the bond in the oxygen atom-containing group. Furthermore, the specific carboxylic acids may be used singly or in combinationTwo or more kinds are used.

When the epoxy group-containing polyorganosiloxane is reacted with a specific carboxylic acid, a carboxylic acid (other carboxylic acid) having no photo-alignment group may be used. The other carboxylic acid to be used is not particularly limited, and a carboxylic acid having a polymerizable group (hereinafter, also referred to as "polymerizable group-containing carboxylic acid") can be preferably used, and a carboxylic acid in which the polymerizable group is a (meth) acryloyl group can be more preferably used. When the epoxy group-containing polyorganosiloxane is reacted with a specific carboxylic acid, a liquid crystal alignment film having more excellent releasability between the optically anisotropic film and the liquid crystal alignment film can be obtained by using a carboxylic acid containing a polymerizable group in combination. As specific examples of the polymerizable group, the above-mentioned descriptions concerning the polymerizable group which the polymer [ A ] may have can be applied. The polyorganosiloxane [ a ] preferably has at least an epoxy group, and more preferably has a (meth) acryloyl group and an epoxy group. The carboxylic acid which is reacted with the epoxy group-containing polyorganosiloxane may also be a carboxylic acid anhydride.

Specific examples of the polymerizable group-containing carboxylic acid include: unsaturated carboxylic acids such as (meth) acrylic acid, maleic acid, fumaric acid, citraconic acid, mesaconic acid, itaconic acid, ω -carboxy-polycaprolactone mono (meth) acrylate, and phthalic acid monohydroxyethyl (meth) acrylate; unsaturated polycarboxylic acid anhydrides such as trimellitic anhydride, maleic anhydride, itaconic anhydride, citraconic anhydride, and cis-1, 2,3, 4-tetrahydrophthalic anhydride. The polymerizable group-containing carboxylic acid may be used alone or in combination of two or more of these. As the other carboxylic acid, for example, propionic acid, benzoic acid, methylbenzoic acid, a carboxylic acid having a vertically oriented group, and the like can be used in addition to the carboxylic acid having a polymerizable group.

In the case of reacting an epoxy group-containing polyorganosiloxane with a carboxylic acid, the proportion of the carboxylic acid to be used is preferably 0.001 to 1.5 moles per 1 mole of the total of epoxy groups in the polyorganosiloxane from the viewpoint of sufficiently proceeding the reaction and reducing the amount of unreacted carboxylic acid, and more preferably 0.01 to less than 1.0 mole, and even more preferably 0.1 to 0.8 mole from the viewpoint of obtaining a liquid crystal alignment film having a more excellent peelability between an optically anisotropic film and a liquid crystal alignment film. In the above reaction, it is preferable that the ratio of the carboxylic acid used is less than 1 mole based on 1 mole of the total of the epoxy groups of the polyorganosiloxane, from the viewpoint that the polyorganosiloxane [ a ] having the photo-alignment group and the epoxy group can be obtained. In order to further improve the releasability between the liquid crystal alignment film and the optically anisotropic film, the polyorganosiloxane [ a ] preferably has an epoxy group in a side chain.

From the viewpoint of improving the liquid crystal alignment property of the liquid crystal alignment film 12, the use ratio of the specific carboxylic acid (the total amount thereof in the case of using two or more kinds) is preferably 10 mol% or more, and more preferably 20 mol% or more, with respect to the total amount of the carboxylic acid used in the reaction. When the carboxylic acid containing a polymerizable group is used, the proportion of the carboxylic acid containing a polymerizable group to be used is preferably 1 mol% or more, more preferably 3 mol% to 50 mol%, and still more preferably 5 mol% to 30 mol% based on the total amount of the carboxylic acid used in the reaction.

The reaction of the epoxy group-containing polyorganosiloxane with the carboxylic acid is preferably carried out in the presence of a catalyst and an organic solvent. As the catalyst, a tertiary organic amine or a quaternary organic amine is preferably used. The proportion of the catalyst used is preferably 0.1 to 20 parts by mass relative to 100 parts by mass of the epoxy group-containing polyorganosiloxane. The organic solvent used is preferably at least one selected from the group consisting of ethers, esters, and ketones, from the viewpoint of solubility of the raw materials and the product and ease of purification of the product. Specific examples of particularly preferred solvents include: 2-butanone, 2-hexanone, methyl isobutyl ketone, butyl acetate, and the like. The organic solvent is preferably used in such a proportion that the solid content concentration (the proportion of the total mass of components other than the solvent in the reaction solution to the total mass of the solution) is 5 to 50 mass%. The reaction temperature is preferably 0 ℃ to 200 ℃ and the reaction time is preferably 0.1 hour to 50 hours. After the reaction is completed, the organic solvent layer separated from the reaction solution is preferably washed with water.

The polyorganosiloxane [ A ] preferably has a weight average molecular weight (Mw) in terms of polystyrene, as measured by Gel Permeation Chromatography (GPC), within a range of 100 to 50,000, more preferably within a range of 200 to 10,000.

(styrene-maleimide copolymer)

In a second polymer [ B]A styrene-maleimide copolymer (hereinafter, also referred to As "polymer [ As ]) having photo-alignment group]") in the case of a polymer [ As ] was synthesized]The method of (3) is not particularly limited. Polymer [ As ]]May further have a polymerizable group. Polymer [ As ]]The polymerizable group is preferably a group capable of forming a covalent bond between the same or different molecules by light or heat, and examples thereof include: a (meth) acryloyl group, a vinyl group, a vinylphenyl group, a vinyl ether group, an allyl group, an ethynyl group, an allyloxy group, a cyclic ether group, and groups represented by the following formulae (22) to (25). In the following formula, R is¹²～R¹⁵Examples of the divalent organic group of (2) include a divalent hydrocarbon group having 1 to 20 carbon atoms, and groups having-O-, -CO-, -COO-or the like between carbon-carbon bonds of the divalent hydrocarbon group. Of these, the polymer [ As]The polymerizable group is preferably a (meth) acryloyl group or an epoxy group, and more preferably an epoxy group.

[ solution 5]

In (formula (22) to (25), R¹²～R¹⁴Each independently being a single bond or a divalent organic radical, R¹⁵Is a divalent organic radical; "+" indicates a bond)

The polymer [ As ] may contain only a structural unit derived from a monomer having a styryl group (hereinafter, also referred to As "styrenic compound") and a structural unit derived from a monomer having a maleimide group (hereinafter, also referred to As "maleimide compound"), or may further contain a structural unit derived from a monomer other than the styrenic compound and the maleimide compound. The content ratio of the structural unit derived from the styrene compound is preferably 2 to 80 mol%, more preferably 5 to 70 mol%, based on all the structural units of the styrene-maleimide copolymer. The content ratio of the structural unit derived from the maleimide-based compound is preferably 2 to 80 mol%, more preferably 5 to 70 mol%, based on all the structural units of the styrene-maleimide-based copolymer.

Specific examples of the styrene-based compound include: styrene, methylstyrene, divinylbenzene, 3-vinylbenzoic acid, 4-vinylbenzoic acid, 3- (glycidyloxymethyl) styrene, 4-glycidyl-alpha-methylstyrene, etc. Examples of the maleimide-based compound include: n-methyl maleimide, N-cyclohexyl maleimide, N-phenylmaleimide, 3- (2, 5-dioxo-3-pyrrolin-1-yl) benzoic acid, 4- (2, 5-dioxo-3-pyrrolin-1-yl) benzoic acid, methyl 4- (2, 5-dioxo-3-pyrrolin-1-yl) benzoate, photo-alignment group-containing compounds represented by the following formulae (m3-1) to (m3-5), respectively, and the like.

[ solution 6]

Further, as the styrene compound and the maleimide compound, one of them may be used alone or two or more of them may be used in combination.

The polymer [ As ] can be obtained by polymerization using a styrene-based compound and a maleimide-based compound. The polymerization is preferably carried out in the presence of a polymerization initiator and in an organic vehicle. As the polymerization initiator to be used, for example, azo compounds such as 2,2' -azobis (isobutyronitrile), 2' -azobis (2, 4-dimethylvaleronitrile), and 2,2' -azobis (4-methoxy-2, 4-dimethylvaleronitrile) are preferable. The use ratio of the polymerization initiator is preferably 0.01 to 30 parts by mass with respect to 100 parts by mass of all monomers used in the reaction. Examples of the organic solvent to be used include: alcohols, ethers, ketones, amides, esters, hydrocarbon compounds, and the like. In this case, the reaction temperature is preferably 30 to 120 ℃ and the reaction time is preferably 1 to 36 hours. The amount (a) of the organic solvent used is preferably 0.1 to 60% by mass of the total amount (b) of the monomers used in the reaction relative to the total amount (a + b) of the reaction solution.

In order to further improve the releasability between the liquid crystal alignment film and the optically anisotropic film, the polymer [ As ] is preferably a styrene-maleimide copolymer having an epoxy group, a functional group that reacts with the epoxy group by heating, and a photo-alignment group. The functional group that reacts with an epoxy group by heating is preferably a carboxyl group or a protected carboxyl group in terms of high storage stability and high reactivity with an epoxy group.

When the polymer [ As ] has an epoxy group and a functional group that reacts with the epoxy group by heating, the content of the epoxy group in the polymer [ As ] is preferably 1 to 60 mol%, more preferably 10 to 50 mol%, based on the total amount of monomers used for synthesizing the polymer [ As ]. The content of the functional group that reacts with the epoxy group by heating is preferably 1 mol% to 90 mol%, more preferably 10 mol% to 80 mol%.

The weight average molecular weight (Mw) of the polymer [ As ] in terms of polystyrene measured by GPC is preferably 1,000 to 300,000, more preferably 2,000 to 100,000. The molecular weight distribution (Mw/Mn) represented by the ratio of Mw to the number average molecular weight (Mn) in terms of polystyrene measured by GPC is preferably 10 or less, more preferably 8 or less.

((meth) acrylic acid-based Polymer)

When the second polymer [ B ] is a (meth) acrylic polymer having photo-alignment groups (hereinafter, also referred to as "polymer [ Am ]"), the method for synthesizing the polymer [ Am ] is not particularly limited. The polymer [ Am ] may further have a polymerizable group.

The polymer [ Am ] preferably has an epoxy group as a polymerizable group in a side chain. Such a polymer [ Am ] can be obtained, for example, by the following method: a monomer containing a (meth) acrylic compound having an epoxy group is polymerized in the presence of a polymerization initiator, and the obtained polymer (hereinafter, also referred to as "epoxy group-containing poly (meth) acrylate") is reacted with a photo-alignment group-containing carboxylic acid. Further, with respect to various conditions in the synthesis reaction, the description of the polymer [ As ] can be applied.

Examples of the epoxy group-containing (meth) acrylic monomer include unsaturated carboxylic acid esters having an epoxy group, and specific examples thereof include: glycidyl (meth) acrylate, glycidyl α -ethylacrylate, 3, 4-epoxybutyl (meth) acrylate, 3, 4-epoxycyclohexylmethyl (meth) acrylate, 6, 7-epoxyheptyl (meth) acrylate, 4-hydroxybutyl glycidyl acrylate, (3-ethyloxetan-3-yl) methyl (meth) acrylate, and the like.

In the polymerization, as the other monomers other than the epoxy group-containing (meth) acrylic monomers, for example, (meth) acrylic acid, maleic acid, vinyl benzoic acid, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, allyl (meth) acrylate, cyclohexyl (meth) acrylate, benzyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, styrene, methylstyrene, N-methylcaleimide, N-cyclohexylmaleimide, N-phenylmaleimide and the like can be used in combination with the epoxy group-containing (meth) acrylic monomers. Further, one of these may be used alone or two or more of these may be used in combination.

The number average molecular weight (Mn) of the polymer [ Am ] in terms of polystyrene measured by GPC is preferably 250 to 500,000, more preferably 500 to 100,000, and still more preferably 1,000 to 50,000.

The second polymer [ B ] is preferably a polyorganosiloxane in terms of making the optical film more excellent in releasability and transparency after transfer.

The content of the second polymer [ B ] is preferably 5 parts by mass or more, more preferably 5 to 90 parts by mass, and still more preferably 10 to 80 parts by mass, based on 100 parts by mass of the total of the polymer components contained in the liquid crystal aligning agent. Further, as one reason, it is presumed that: by having any of the main skeletons of the second polymer [ B ], the adhesiveness of the liquid crystal alignment film to the optical film is appropriately weakened, and thus the peelability of the optical film can be improved.

In the liquid crystal aligning agent of the present embodiment, either one or both of the first polymer [ a ] and the second polymer [ B ] may have a polymerizable group, in order to obtain a liquid crystal alignment film which can improve the releasability from an optical film, the transparency, and the liquid crystal alignment property. In this case, the optical film is preferable because the effect of improving the peelability, transparency, and liquid crystal alignment properties of the optical film with respect to the liquid crystal alignment film is high. Further, the reason why the effect is further enhanced when the component in the liquid crystal aligning agent has a polymerizable group is presumed to be: the hardness of the liquid crystal alignment film is increased by intermolecular or intramolecular crosslinking due to the polymerizable group, and the adhesiveness of the liquid crystal alignment film to the support is improved, whereby the optical anisotropic film is perfectly peeled from the liquid crystal alignment film, and as a result, the alignment regulating force and the transparency of the optical anisotropic film are increased.

The polymerizable group is preferably a group capable of forming a covalent bond between the same or different molecules by light or heat, and examples thereof include: (meth) acryloyl, vinyl, vinylphenyl, vinylene, vinyloxy (CH)₂CH — O-), maleimido group, allyl group, ethynyl group, allyloxy group, cyclic ether group (oxetanyl group, etc.), and the like. Among these, (meth) acryloyl groups and epoxy groups are preferable in terms of high reactivity to light. Further, the term "(meth) acryloyl group" means an acryloyl group and a methacryloyl group, and the term "epoxy group" means an oxetanyl group and an oxetanyl group. Relative to the constitution of the first polymer [ A ]]And a second polymer [ B]The total amount of the monomer units (b) is preferably 1 mol% or more, more preferably 2 mol% or more, based on the content of the polymerizable group. In addition, the first and second substrates are,relative to the constitution of the first polymer [ A ]]And a second polymer [ B]The total amount of the monomer units (a) is preferably 50 mol% or less, more preferably 40 mol% or less, based on the content of the polymerizable group.

The preferred use ratio of the first polymer [ a ] and the second polymer [ B ] is preferably 100 parts by mass or more, more preferably 150 parts by mass or more, and still more preferably 200 parts by mass or more, relative to 100 parts by mass of the polymer [ B ]. The amount of the polymer [ A ] used is preferably 100,000 parts by mass or less, more preferably 5,000 parts by mass or less, and still more preferably 3,000 parts by mass or less, per 100 parts by mass of the polymer [ B ].

Other ingredients

The liquid crystal aligning agent of the present embodiment may contain other components than the first polymer [ a ] and the second polymer [ B ] as required. Examples of the other component include a polymer different from the first polymer [ a ] and the second polymer [ B ] (hereinafter, also referred to as "other polymer"), a curing catalyst, a curing accelerator, and the like.

(other Polymer)

The other polymers are not particularly limited, and examples thereof include: the polymer is a polymer having no photo-alignment group and having a main skeleton such as polyamic acid, polyamic acid ester, polyimide, polyester, polyamide, cellulose derivative, polyacetal, polystyrene derivative, styrene-maleimide copolymer, or (meth) acrylic polymer. The other polymer is more preferably a polyamide acid, a polyamic acid ester, a polyimide, or a (meth) acrylic polymer having a main chain thereof. Further, as the other polymer, one kind may be used alone, or two or more kinds may be used in combination. When another polymer is blended, the ratio of the other polymer to the total amount of the first polymer [ a ], the second polymer [ B ] and the other polymer is preferably 90% by mass or less, more preferably 80% by mass or less, still more preferably 50% by mass or less, and particularly preferably 20% by mass or less.

(curing catalyst)

The curing catalyst is a component having a catalytic action for the crosslinking reaction between epoxy structures, and is contained in the liquid crystal aligning agent for the purpose of promoting the crosslinking reaction. The hardening catalyst is preferably a metal chelate compound, and is preferably an acetylacetone complex or an acetoacetic acid complex using a metal selected from aluminum, titanium, and zirconium. Specific examples thereof include: aluminum diisopropoxyethylacetoacetate, aluminum tris (acetylacetonate), aluminum tris (ethylacetoacetate), titanium diisopropoxybis (acetylacetonate), zirconium tris-n-butoxyethylacetoacetate, zirconium di-n-butoxybis (ethylacetoacetate), and the like. The metal chelate compound is used in a proportion of preferably 0.1 to 50 parts by mass, more preferably 0.5 to 30 parts by mass, based on 100 parts by mass of the total polymer components in the liquid crystal aligning agent.

(hardening accelerator)

The curing accelerator is a component contained in the liquid crystal aligning agent for the purpose of enhancing the catalytic action of the curing catalyst and accelerating the crosslinking reaction between epoxy structures. Examples of the hardening accelerator include compounds having a phenol group, a silanol group, a thiol group, a phosphoric acid group, a sulfonic acid group, a carboxyl group, and a carboxylic anhydride group. Specific examples of the hardening accelerator include: cyanophenol, nitrophenol, methoxyphenoxyphenol, thiophenophenol, 4-benzylphenol, trimethylsilanol, triethylsilanol, 1,3, 3-tetraphenyl-1, 3-disiloxane diol, 1, 4-bis (hydroxydimethylsilyl) benzene, triphenylsilanol, tri (p-tolyl) silanol, diphenylsilanediol, trimellitic acid, and the like. The use ratio of the curing accelerator is preferably 30 parts by mass or less, and more preferably 0.1 to 20 parts by mass, relative to 100 parts by mass of the total polymer components in the liquid crystal aligning agent.

The liquid crystal aligning agent may contain other components than those described above within a range not to impair the object and effect of the present invention. Examples of the components include: a compound having at least one epoxy group in the molecule, a functional silane compound, a surfactant, silica particles, a filler, an antifoaming agent, a photosensitizer, a dispersant, an antioxidant, an adhesion promoter, an antistatic agent, an antibacterial agent, an ultraviolet absorber, and the like. The blending ratio of these compounds may be appropriately set within a range not to impair the effects of the present invention depending on each compound to be blended.

(solvent)

The liquid crystal aligning agent is prepared in the form of a liquid composition in which the first polymer [ a ], the second polymer [ B ] and optionally other components are preferably dispersed or dissolved in an appropriate solvent.

The solvent used is preferably an organic solvent. As the solvent, alcohols, ethers, ketones, amides, esters, hydrocarbons, and the like can be suitably used. Among them, it is preferable to use one or more solvents (hereinafter, also referred to as "a solvent") selected from partial esters of polyhydric alcohols, polyhydric alcohol ethers, ketones, and esters. Specifically, as the partial ester of the polyhydric alcohol, propylene glycol monomethyl ether acetate; as the polyol ether, one or more selected from propylene glycol monomethyl ether and ethylene glycol monobutyl ether (butyl cellosolve) can be preferably used; as the ether, one or more selected from diethylene glycol ethyl methyl ether and tetrahydrofuran; as the ketone, one or more selected from methyl ethyl ketone, cyclopentanone, and cyclohexanone; as the ester, one or more selected from ethyl acetate, n-butyl acetate, isobutyl acetate, tert-butyl acetate, ethyl acetoacetate, and propylene glycol monomethyl ether acetate can be preferably used.

In the production of the liquid crystal aligning agent, the solvent A may be used alone or in combination with another solvent (hereinafter, also referred to as "B solvent"). The solvent B includes aprotic polar solvents, and examples thereof include: n-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, γ -butyrolactone, 1, 2-dimethyl-2-imidazolidinone, N-dimethylformamide, and the like. The solvent B may be used singly or in combination of two or more.

The ratio of the solvent A and the solvent B to be used may be appropriately selected depending on the solubility of the polymer in the solvent. Specifically, the ratio of the solvent a to the total amount of solvents used for producing the liquid crystal aligning agent is preferably 5% by mass or more, and more preferably 10% by mass or more. The ratio of the B solvent to the total amount of the solvents used for the preparation of the liquid crystal aligning agent is preferably 95% by mass or less, and more preferably 90% by mass or less. The ratio of the B solvent to the total amount of the solvents used for producing the liquid crystal aligning agent is preferably 5 mass% or more, and more preferably 10 mass% or more.

From the viewpoint of making the coatability of the liquid crystal aligning agent and the film thickness of the formed coating film appropriate, the use ratio of the solvent is preferably a ratio such that the solid content concentration of the liquid crystal aligning agent (the ratio of the total mass of all components other than the solvent in the liquid crystal aligning agent to the total mass of the polymer composition) becomes 0.2 to 10 mass%, and more preferably a ratio of 3 to 10 mass%.

< laminate and method for producing same >

As shown in fig. 1 (a) to (c), the laminate 10 of the present embodiment is formed by sequentially laminating a support 11, a liquid crystal alignment film 12, and an optical film 13. The optical film 13 is a film containing a liquid crystal compound, and may be a film containing a single layer or a film containing a plurality of layers. Examples of the case where the optical film 13 has a multilayer structure include: a multilayer structure in which two or more liquid crystal layers having different retardation (retardation) are stacked; a multilayer structure in which another layer (e.g., an adhesive layer or an adhesive layer) is interposed between the liquid crystal layer and the liquid crystal layer. The laminate 10 can be produced, for example, by a method including the following steps 1 to 3.

(step 1: formation of coating film)

First, a liquid crystal aligning agent is applied to the support 11, and preferably, the applied surface is heated, thereby forming a coating film on the support 11. As the support 11, a transparent resin film can be preferably used. Specific examples thereof include: a film containing a synthetic resin such as cellulose acylate, polyethylene terephthalate, polybutylene terephthalate, polysulfone, polyethersulfone, polyetheretherketone, polyamide, polyimide, poly (meth) acrylate, polymethyl methacrylate, polycarbonate, cyclic polyolefin, or the like. Of these, the support 11 is preferably formed of a resin material of triacetyl cellulose, polyethylene terephthalate, poly (meth) acrylate, polycarbonate, or polyether ether ketone. The support 11 formed of these resin materials is preferable in that it has appropriate resistance to a solvent (only the a solvent or a mixed solvent of the a solvent and the B solvent) suitably used in the production of the liquid crystal aligning agent containing the first polymer [ a ] and the second polymer [ B ], and adhesion of the liquid crystal alignment film formed on the support 11 to the support 11 and liquid crystal alignment properties can be further improved. In order to improve the adhesion between the surface of the support 11 and the liquid crystal alignment film 12, the support 11 to be used may be subjected to a conventionally known pretreatment such as saponification treatment on the surface on which the liquid crystal alignment film 12 is formed.

The liquid crystal aligning agent can be applied to the support 11 by a suitable application method. Specifically, for example, there can be adopted: a roll coater method, a spinner method, an inkjet printing method, a bar coater method, an extrusion die (extrusion die) method, a direct gravure coater method, a chamber knife coater method, an offset gravure coater method, an impregnation coater method, an MB coater method, and the like. After the liquid crystal aligning agent is applied, the applied surface is preferably heated (baked). The heating temperature in this case is preferably 40 to 150 ℃, more preferably 80 to 140 ℃. The heating time is preferably 0.1 to 15 minutes, more preferably 1 to 10 minutes. The film thickness of the coating film formed on the support 11 is preferably 1nm to 1 μm, and more preferably 5nm to 0.5 μm. Thereby, a coating film to be the liquid crystal alignment film 12 is formed on the support 11.

(step 2: photo-alignment treatment)

Then, the coating film formed on the substrate in the above manner is irradiated with light to impart liquid crystal alignment ability to the coating film, thereby forming the liquid crystal alignment film 12. Examples of the irradiation light include ultraviolet rays and visible rays including light having a wavelength of 150nm to 800 nm. Of these, ultraviolet rays containing light having a wavelength of 300nm to 400nm are preferable. The illumination light may be polarized or unpolarized. As the polarized light, light including linearly polarized light is preferably used. When the light to be used is polarized light, the substrate surface may be irradiated from a vertical direction, the substrate surface may be irradiated from an oblique direction, or a combination of these directions may be performed. When unpolarized light is irradiated, it is necessary to irradiate the substrate surface from an oblique direction.

Examples of the light source used include: low-pressure mercury lamps, high-pressure mercury lamps, deuterium lamps, metal halide lamps, argon resonance lamps, xenon lamps, mercury-xenon lamps (Hg-Xe lamps), and the like. The polarization can be obtained by a method of using these light sources in combination with, for example, a filter, a diffraction grating, or the like. The irradiation amount of light is preferably set to 0.1mJ/cm²～1,000mJ/cm²More preferably 1mJ/cm²～500mJ/cm²。

(step 3: formation of optical film)

Then, a liquid crystal composition containing a polymerizable liquid crystal compound is applied to the coating film (liquid crystal alignment film 12) irradiated with light in the above-described manner and cured. Thereby, the optical film 13 as a transfer film having an optical function is formed on the surface of the liquid crystal alignment film 12. The polymerizable liquid crystal compound used herein is a liquid crystal compound that is polymerized by at least one of heating and light irradiation. Examples of the polymerizable group of the polymerizable liquid crystal compound include a (meth) acryloyl group, a vinyl group, a vinylphenyl group, and an allyl group, and a (meth) acryloyl group is preferable.

As the polymerizable liquid crystal compound, any liquid crystal compound having a polymerizable functional group may be used, and conventionally known ones can be used. Specifically, examples thereof include nematic liquid crystals described in non-patent document 1 (UV-curable liquid crystals and applications thereof, liquid crystals, Vol.3, No. 1 (1999), pp 34-42). In this case, a liquid crystal compound having a (meth) acryloyl group and a mesogen (mesogen) skeleton is preferable. Further, the liquid crystal may be a cholesteric liquid crystal, a discotic liquid crystal (discotic crystal), a twisted nematic liquid crystal to which a chiral agent is added, or the like. When the optically anisotropic film as the optical film 13 is formed using a polymerizable liquid crystal compound, a mixture of a plurality of liquid crystal compounds may be used, and a composition containing a known polymerization initiator, an appropriate solvent, a polymerizable monomer, a surfactant, or the like may be further used. When the polymerizable liquid crystal compound is applied to the liquid crystal alignment film 12 formed, an appropriate application method such as a bar coater method, a roll coater method, a spinner method, a printing method, and an ink jet method can be used.

The liquid crystal composition may contain both a polymerizable liquid crystal compound and a coloring matter. By using the liquid crystal composition containing a dye, an anisotropic dye film having a polarizing function can be formed as the optical film 13. The dye is a compound that absorbs at least a part of the wavelength in the visible light region (380nm to 780nm), and a dichroic dye is preferably used.

The pigment is not particularly limited, and a known compound can be used. Specific examples of the coloring matter include: azo-based pigments, naphthoquinone-based pigments, anthraquinone-based pigments, cyanine-based pigments, phthalocyanine-based pigments, stilbene (stilbene) -based pigments, perylene-based pigments, oxazine-based pigments, acridine-based pigments, indigo-based pigments, polyiodide, and the like. Among these, azo dyes or anthraquinone dyes are preferable, and azo dyes (e.g., disazo compounds, trisazo compounds, tetraazo compounds, etc.) are particularly preferable, from the viewpoint of excellent light resistance and high dichroism. Examples of the known dye compounds include dichroic dyes described in Japanese patent laid-open Nos. Hei 1-105204, 2012-083734, 2014-095899, and 2017-025317. One kind of the coloring matter may be used alone, or two or more kinds may be used in combination.

When the dye is contained in the liquid crystal composition, the content ratio of the dye is preferably 0.01% by mass or more, and more preferably 0.05% by mass or more, relative to the total amount of the liquid crystal composition. The content of the coloring matter is preferably 30% by mass or less, more preferably 20% by mass or less, and still more preferably 10% by mass or less, based on the total amount of the liquid crystal composition. When the amount of the coloring matter is 0.05% by mass or more, an optical film that sufficiently exhibits a polarizing function can be obtained, and when the amount is 30% by mass or less, the influence of the decrease in the alignment ability due to the excessive coloring matter can be reduced, which is preferable.

Then, the coating film of the polymerizable liquid crystal compound formed in the above manner is subjected to one or more treatments selected from heating and light irradiation, thereby hardening the coating film to form a liquid crystal layer (optical film 13). These treatments are preferably performed in an overlapping manner in terms of obtaining good orientation. The heating temperature of the coating film can be appropriately selected depending on the kind of the polymerizable liquid crystal compound to be used. For example, in the case of using RMS03-013C manufactured by Merck, it is preferable to heat at a temperature in the range of 40 ℃ to 80 ℃. The heating time is preferably 0.5 to 5 minutes. As the irradiation light to the coating film, unpolarized ultraviolet rays having a wavelength in the range of 200nm to 500nm can be preferably used. The dose of light irradiation is preferably 50mJ/cm²～10,000mJ/cm²More preferably, it is 100mJ/cm²～5,000mJ/cm². The coating film may be irradiated with polarized radiation only once from a predetermined polarization direction, or the coating film may be irradiated with radiation having a different polarization direction (incident direction) a plurality of times.

The thickness of the optical film 13 to be formed may be appropriately set according to desired optical characteristics. For example, when an 1/2-wavelength plate of visible light having a wavelength of 540nm is produced as the retardation film, the thickness of the optical film 13 as the retardation film is selected to be 240nm to 300nm, and when the retardation film is a 1/4-wavelength plate, the thickness of the optical film is selected to be 120nm to 150 nm. The thickness of the optical film 13 that can obtain the target retardation varies depending on the optical characteristics of the polymerizable liquid crystal compound used. For example, in the case of RMS03-013C manufactured by Merck (Merck), the thickness of the plate used to manufacture 1/4 wavelength plates ranged from 0.6 μm to 1.5 μm. Thus, a laminate 10 was obtained. In the case where the optical film 13 has a multilayer structure, the optical film 13 can be obtained by repeating, for example, application and curing of a polymerizable liquid crystal compound.

< method for forming optical compensation film >

According to the laminate 10, the optical film 13 included in the laminate 10 is transferred to the adherend 21 (see fig. 1 (b)), whereby the optical film as the transfer film 23 can be formed on the adherend 21 (see fig. 1 (c)). Specifically, first, the laminate 10 is obtained in the above-described manner (see fig. 1 (a)), and then, the surface of the laminate 10 on the optical film 13 side is bonded to one surface of the adherend 21 (see fig. 1 (b)). In this case, the adhesive layer 22 may be formed on at least one of the surface of the laminate 10 on the optical film 13 side and the surface of the adherend 21, and the laminate 10 may be bonded to the adherend 21 via the adhesive layer 22. Then, the support 11 is separated from the adherend 21. This causes peeling at the boundary between the liquid crystal alignment film 12 and the optical film 13, and the optical film 13 is transferred to the surface of the adherend 21. In this manner, the optical film 13 (transfer film 23) is formed on the adherend 21 (see fig. 1 (c)). Examples of the optical film 13 include: a retardation film, a viewing angle compensation film, an antireflection film, and the like.

The adherend 21 to which the optical film 13 is transferred is not particularly limited. For example, a liquid crystal cell in which a liquid crystal layer is provided between a pair of substrates disposed to face each other is constructed, and the adherend 21 is a pair of substrates (for example, glass substrates) in the liquid crystal cell. Then, the surface of the laminate 10 on the optical film 13 side is bonded to the outer side of at least one of the pair of substrates, and the optical film 13 is transferred. Thereby, the following liquid crystal display element can be obtained: a transfer film 23 including an optical film 13 is provided on the outer sides of the pair of substrates in the liquid crystal cell. Alternatively, the optical film 13 may be transferred by laminating the polarizing film as the adherend 21 and the surface of the laminate 10 on the optical film 13 side to the polarizing film (preferably, to the surface on the polarizing layer side of the polarizing film). When the optical film 13 is transferred to the polarizing layer side surface of the polarizing film, the transferred surface of the polarizing film preferably includes a material with little shrinkage at the time of transfer. Specifically, the surface of a protective layer containing Triacetyl Cellulose (TAC) or a liquid crystal layer having iodine adsorbed on polyvinyl alcohol may be a transfer target surface.

In the case where the optical film 13 is a phase difference film, a polarizing film (polarizing film with a phase difference film) having the optical film 13 can be obtained thereby. The polarizing film with the retardation film can be used as a circular polarizing plate, for example. The optical film 13 is useful as an optical film having an antireflection function by being combined with a linear polarizing plate. The adherend 21 is preferably a glass substrate, a triacetylcellulose substrate, or a polyvinyl alcohol substrate, and more preferably a glass substrate or a triacetylcellulose substrate.

The transfer of the optical film 13 may be performed a plurality of times using a plurality of laminated bodies 10 for the adherend 21. Specifically, first, a first laminate in which a first liquid crystal alignment film and a first optical film are sequentially laminated on a support is bonded to one surface of the adherend 21, and the first optical film is transferred to the adherend 21. Then, a second laminate in which the second liquid crystal alignment film and the second optical film are sequentially laminated on the support is bonded to the surface of the adherend 21 on which the first optical film is formed, and the second optical film is transferred onto the surface of the first optical film. Thus, an optical film including a multilayer structure including the first optical film and the second optical film can be formed on one surface of the adherend 21. In the optical film having a multilayer structure, the optical film is not limited to two layers, and may have three or more layers. In the case where the adherend is a liquid crystal cell including a pair of substrates disposed to face each other and a liquid crystal layer disposed between the pair of substrates, the optical film side of the laminate is bonded to the outside of at least one of the substrates of the liquid crystal cell, and the support and the liquid crystal alignment film are peeled off, whereby a liquid crystal element with an optical film can be obtained.

EXAMPLE 2 EXAMPLE

The circularly polarizing plate of the present embodiment and the liquid crystal aligning agent used for producing the circularly polarizing plate will be described. The circularly polarizing plate of the present embodiment is formed by sequentially laminating a retardation layer, a resin layer, a liquid crystal alignment film, and a polarizing layer. Hereinafter, the components of the circularly polarizing plate of the present embodiment and the liquid crystal aligning agent for forming the liquid crystal alignment film will be described mainly with respect to differences from the liquid crystal aligning agent of embodiment 1.

Fig. 2 shows an example of the circularly polarizing plate 30 of the present embodiment. The circularly polarizing plate 30 includes a substrate 31, a first alignment film 32, a phase difference layer 33, a resin layer 34, a second alignment film 35, and a polarizing layer 36, and these layers are laminated in this order. As the substrate 31, a transparent resin film or a glass substrate can be used. As specific examples and preferable examples of the resin film, the description of the support 11 of embodiment 1 can be applied.

The first alignment film 32 and the second alignment film 35 are formed using a liquid crystal alignment agent containing a polymer having a photo-alignment group (hereinafter, also referred to as "polymer [ P ]). As specific examples and preferable examples of the photo-alignment group contained in the polymer [ P ], the description of the first polymer [ a ] in embodiment 1 can be applied. The main chain of the polymer [ P ] is not particularly limited, and a polymer having a photo-alignment group (i.e., the first polymer [ a ]) is preferably at least one polymer selected from the group consisting of polyamic acids, polyimides, and polyamic acid esters, from the viewpoint of obtaining a circular polarizing plate having excellent polarizing performance.

The liquid crystal aligning agent used to form the first alignment film 32 and the second alignment film 35 may contain only the first polymer [ a ] as a polymer component. Alternatively, the liquid crystal aligning agent may contain the first polymer [ A ] and the second polymer [ B ], and may also contain the first polymer [ A ] and other polymers. The first alignment film 32 and the second alignment film 35 may be formed using a liquid crystal aligning agent having the same composition, or may be formed using a liquid crystal aligning agent having a different composition.

The resin layer 34 is preferably formed using a liquid polymer composition in which a polymer is dissolved in a solvent. The polymer (hereinafter, also referred to as "polymer [ Q ]") contained in the polymer composition is preferably at least one selected from the group consisting of a polyorganosiloxane, (meth) acrylic polymer, and a styrene-maleimide copolymer, and particularly preferably a polyorganosiloxane, from the viewpoint of sufficiently improving the liquid crystal alignment function by the second alignment film 35 and forming the polarizing layer 36 exhibiting an excellent polarizing function. The polymer as a constituent of the resin layer 34 preferably has no photo-alignment group.

The polymer [ Q ] preferably has a crosslinkable group. The polymer [ Q ] having a crosslinkable group is preferable in that it can form the circularly polarizing plate 30 having a further excellent polarizing function. The crosslinkable group is preferably a group capable of forming a covalent bond between the same or different molecules by light or heat, and examples thereof include: a (meth) acrylic acid-containing group having a (meth) acrylic acid or a derivative thereof as a basic skeleton, a group having a vinyl group (an alkenyl group, a styryl group, or the like), an ethynyl group, an epoxy group (an oxetanyl group ), or the like. Among these, the crosslinkable group of the polymer [ Q ] is particularly preferably an epoxy group.

When the polymer composition used for forming the resin layer 34 contains the polymer [ Q ] having a crosslinkable group, it preferably contains at least one selected from the group consisting of a curing catalyst and a curing accelerator. The description of embodiment 1 can be applied to specific examples of the curing catalyst, the curing accelerator, and the solvent. The thickness of the resin layer 34 is preferably 1nm to 1 μm, and more preferably 5nm to 0.5 μm.

The retardation layer 33 and the polarizing layer 36 are each formed by curing a liquid crystal compound. Of these, from the viewpoint of imparting a sufficient polarizing function to the film, it is preferable that the liquid crystal composition used for forming the polarizing layer 36 contains both a liquid crystal compound and a coloring matter. The description of embodiment 1 can be applied to specific examples and preferred examples of the coloring matter.

Next, a process for producing the circularly polarizing plate 30 will be described. First, a liquid crystal aligning agent is applied to the substrate 31, and preferably, the applied surface is heated, thereby forming a coating film on the substrate 31. Then, the coating film is irradiated with light to impart liquid crystal alignment capability to the coating film, thereby forming the first alignment film 32 as a photo-alignment film. Then, the liquid crystal composition is applied to the first alignment film 32 and cured, thereby forming the retardation layer 33. Thereafter, a polymer composition containing the polymer [ Q ] is applied to the retardation layer 33, and preferably subjected to heat treatment, reduced pressure treatment, or the like, to form a resin layer 34. In forming the resin layer 34, the description of step 1 in embodiment 1 can be applied to a method for applying a polymer composition, and the like.

Thereafter, a liquid crystal aligning agent is further applied to the resin layer 34 to form a coating film, and the coating film is subjected to photo-alignment treatment to form a second alignment film 35. Further, a liquid crystal composition (preferably, a liquid crystal composition containing a dye) is applied onto the second alignment film 35 and cured to form the polarizing layer 36. Thus, the circularly polarizing plate 30 is obtained. The circularly polarizing plate 30 may be in the form of a film or a sheet.

In embodiment 2, the case where the first alignment film 32 is formed on the substrate 31 and the retardation layer 33 is formed on the first alignment film 32 has been described, but the retardation layer 33 may be formed by using the laminate of embodiment 1, that is, the laminate including the support 11, the liquid crystal alignment film 12, and the retardation film as the optical film 13, and transferring the retardation film of the laminate onto the substrate 31. In this case, a circularly polarizing plate not including the first alignment film 32 can be manufactured.

Here, if the layers of the circularly polarizing plate are formed by a liquid phase process, it is considered that thinning of the circularly polarizing plate, reduction of manufacturing cost, and the like can be achieved. On the other hand, when the film is formed by a liquid-phase process, a circular polarizing plate exhibiting a sufficient polarizing function may not be obtained due to the influence of one layer adjacent to the other layer.

In view of such a problem, according to the coating-type circularly polarizing plate 30 of the present embodiment, each layer can be manufactured by film formation using a liquid phase process, and a circularly polarizing plate exhibiting an excellent polarizing function can be manufactured by a relatively simple manufacturing method. In addition, by providing the resin layer 34 between the retardation layer 33 and the second alignment film 35, the liquid crystal alignment ability of the second alignment film 35 can be secured, and the function of the polarizing layer 36 can be sufficiently improved.