Liquid crystal polymer film and its manufacturing method

Abstract

To provide a method which can alleviate restrictions of a producing condition, with which chemical structures of various liquid crystal polymers can be designed and a liquid crystal polymer film having predetermined physical properties and characteristics can be produced.SOLUTION: A production method of the liquid crystal polymer film at least includes: a film forming step of forming a polymer film comprising a mesogenic component and a side chain type liquid crystal polymer including a side chain having a hydrolyzable group and a side chain having a photosensitive group; a light irradiation step of making the obtained polymer film irradiated with light capable of making the mesogenic component anisotropically oriented due to a photoreaction of the photosensitive group; a heating orientation step of heating the photo-irradiated polymer film so as to induce orientation of a non-oriented mesogenic component; a hydrolysis step of subjecting the hydrolyzable group to a hydrolysis reaction by heating the polymer film so as to generate a side chain residue together with eliminated compounds; an application step of applying a condensable compound having a condensable group capable of condensation-reacting with the side chain residue to the polymer film; and a condensation reaction step of conducting a condensation reaction of the side chain residue with the condensable compound.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a liquid crystal polymer film, a method for producing the same, and an optically anisotropic element using the liquid crystal polymer film. [Background technology]

[0002] In Patent Document 1 (Japanese Patent No. 6518934), the present inventors have proposed a liquid crystal polymer film having optical anisotropy and liquid crystal alignment ability, which is produced by forming a photosensitive liquid crystal polymer film by subjecting a film of a polymer capable of forming a photosensitive liquid crystal polymer by a condensation reaction, and then irradiating the obtained photosensitive liquid crystal polymer film with light capable of anisotropically aligning the mesogen moiety.

[0003] Furthermore, in Patent Document 2 (Japanese Patent No. 6644310), we have proposed a liquid crystal polymer film with orientation divided into out-of-plane and in-plane orientation, which is produced by laminating an easily removable masking material on a photosensitive liquid crystal polymer film, heat-treating the laminate, and then irradiating it with light that can anisotropically orient the mesogen moiety.

[0004] Furthermore, in Patent Document 3 (JP 2019-85433 A), a liquid crystal polymer film with excellent light resistance has been proposed, which is produced by irradiating a photo-alignable polymer film containing a copolymer having a side chain (1) capable of forming a liquid crystal structure and having a photosensitive group that can be removed by a hydrolysis reaction, and a side chain (2) capable of forming a liquid crystal structure and having a functional group that has catalytic activity in the hydrolysis reaction, or a polymer composite containing a polymer having side chain (1) and a polymer having side chain (2), with light that can anisotropically align the liquid crystal structure, and then heating and causing a hydrolysis reaction to remove the photosensitive group.

[0005] When the materials for forming liquid crystal polymer films described in Patent Documents 1 to 3 are formed on a substrate and then irradiated with linearly polarized ultraviolet light, an axis-selective photoreaction occurs due to the photosensitive groups contained in the polymer side chains. Furthermore, when such a film is heated, the side chains that have undergone an axis-selective photoreaction due to the liquid crystallinity of the material itself can align the side chains that did not react to the linearly polarized ultraviolet light. As a result, the entire film can be molecularly oriented. This film can be used as a liquid crystal alignment film because it exhibits the ability to align liquid crystal molecules. Furthermore, it can be used as a retardation film because it exhibits birefringence due to molecular orientation. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 6518934 [Patent Document 2] Patent No. 6644310 [Patent Document 3] Japanese Patent Application Publication No. 2019-85433 Summary of the Invention [Problem to be solved by the invention]

[0007] It is possible to control the molecular orientation of liquid crystal polymers using materials for forming liquid crystal polymer films described in Patent Documents 1 to 3. However, Patent Documents 1 to 3 do not allow the use of materials that have low solubility in solvents and are difficult to dissolve as raw materials for film formation. Furthermore, even if a solvent is available in which the raw material has high solubility, if the solution corrodes the substrate, the raw material cannot be used.

[0008] Even if film formation is possible, some liquid crystal polymers have chemical structures that make it difficult to induce molecular orientation unless the heating temperature is high when they are heated to induce molecular orientation of unreacted side chains after being irradiated with light capable of anisotropically orienting the mesogen moieties in order to align the side chains of the liquid crystal polymer. When such liquid crystal polymers are used as raw materials, it becomes difficult to set the manufacturing conditions.

[0009] Furthermore, there are liquid crystal polymers whose chemical structures make them difficult to be photo-aligned in the first place, and therefore, it is not possible to prepare optically anisotropic liquid crystal polymer films using such liquid crystal polymers.

[0010] Therefore, the present invention has been made based on these problems, and aims to provide a method that can relax the constraints on manufacturing conditions that have been previously imposed, that can design the chemical structures of liquid crystal polymers that constitute various liquid crystal polymer films, and that can manufacture liquid crystal polymer films having predetermined physical properties and characteristics.

[0011] Another object of the present invention is to provide a liquid crystal polymer film having improved birefringence and heat resistance, or a liquid crystal polymer film capable of emitting polarized light. [Means for solving the problem]

[0012] As a result of intensive research to solve the above problems, the inventors of the present invention have found that by adopting a production method in which (i) a polymer film containing a photosensitive liquid crystal polymer having side chains with hydrolyzable groups is formed, (ii) the obtained polymer film is irradiated with light and heated to orient the photosensitive liquid crystal polymer, (iii) the hydrolyzable groups in the photosensitive liquid crystal polymer are hydrolyzed, and (iv) the resulting side chain residues are reacted with a condensable compound capable of condensation reaction with these residues, (I) it is possible to select and use a photosensitive liquid crystal polymer that has good solubility as a raw material before light irradiation and that is easy to control the molecular orientation, (II) it is possible to maintain the orientation even if the side chains are hydrolyzed after molecular orientation, and (III) it is possible to introduce a desired side chain structure using a condensable compound, and therefore it is possible to produce a liquid crystal polymer film with predetermined physical properties and characteristics regardless of the molecular orientation of the desired side chain structure, and have completed the present invention.

[0013] That is, the present invention can be configured in the following manner. [Aspect 1] a film-forming step of forming a polymer film containing a side-chain liquid crystal polymer having a mesogen component, a side chain having a hydrolyzable group, and a side chain having a photosensitive group; a light irradiation step of irradiating the obtained polymer film with light capable of causing a photoreaction of the photosensitive groups and anisotropically orienting the mesogen components; a thermal orientation step of heating the light-irradiated polymer film to induce orientation of the unoriented mesogen components; a hydrolysis step of heating the polymer film to hydrolyze the hydrolyzable groups and generate side chain residues together with the elimination compound; a coating step of coating a polymer film with a condensable compound having a condensable group capable of undergoing a condensation reaction with a side chain residue; a condensation reaction step in which a condensation reaction is carried out between the side chain residue and a condensable compound; A method for producing a liquid crystal polymer film, comprising at least the steps of: [Aspect 2] The method for producing a liquid crystal polymer film according to aspect 1, wherein the condensable group of the side chain residue is an aldehyde group or an amino group, and the condensable compound is at least one compound selected from the group consisting of compounds represented by the following formulas (5) to (7): [ka] (wherein c is an integer of 0 to 3 (preferably 1 to 3); Z1 is a single bond, -O-, -COO-, -OCO-, -N=N-, -NO=N-, -CH=CH-, -C≡C-, -CO-CH=CH-, -CH=CH-CO-, -CH=N-, or -N=CH-; Q3 is -NH2 or -CHO; R8 is a hydrogen atom, an alkyl group, an alkyloxy group, a halogen atom, a cyano group, an amino group, an aldehyde group, a carboxy group, or a cinnamic acid group; R9 and R 10 are the same or different and are a hydrogen atom, an alkyl group, an alkyloxy group, a halogen atom, or a cyano group. [ka] (wherein, d and e are the same or different and are integers of 0 to 2; Z2 and Z3 are the same or different and are a single bond, -O-, -COO-, -OCO-, -N=N-, -NO=N-, -CH=CH-, -C≡C-, -CO-CH=CH-, -CH=CH-CO-, -CH=N-, or -N=CH-; Q4 is -NH2 or -CHO; R 11 is a hydrogen atom, an alkyl group, an alkyloxy group, a halogen atom, a cyano group, an amino group, or an aldehyde group; R 12 , R 13 , R 14 , R 15 , R 16 , and R 17 are the same or different and are a hydrogen atom, an alkyl group, an alkyloxy group, a halogen atom, or a cyano group. [ka] (wherein f is an integer of 0 to 3; Z4 is a single bond, -O-, -COO-, -OCO-, -N=N-, -NO=N-, -CH=CH-, -C≡C-, -CO-CH=CH-, -CH=CH-CO-, -CH=N-, or -N=CH-; R 18 is a hydrogen atom, an alkyl group, an alkyloxy group, a halogen atom, a cyano group, or a carboxy group; R 19 and R 20 are the same or different and are a hydrogen atom, an alkyl group, an alkyloxy group, a halogen atom, or a cyano group. Aspect 3 The method for producing a liquid crystal polymer film according to aspect 1 or 2, wherein the side chain of the side chain liquid crystal polymer has a side chain structure represented by the following formula (1): [ka] (In the formula, a is 0 or 1; p is an integer of 0 to 12; q is 0 or 1; X is a single bond, -COO-, -OCO-, or -C≡C-; Q is -CH=N- or -N=CH-; and R1, R2, R3, and R4 are the same or different and each is a hydrogen atom, an alkyl group, an alkyloxy group, a halogen atom, or a cyano group.) Aspect 4 A method for producing a liquid crystal polymer film according to any one of aspects 1 to 3, wherein in the polymer film obtained in the film formation step, the side chain liquid crystal polymer is a copolymer further having a side chain structure represented by the following formula (2), and / or further contains a polymer having a side chain structure represented by the following formula (2): [ka] (In the formula, b is 0 or 1; r is an integer of 0 to 12; s is 0 or 1; Y is a single bond, -COO-, -OCO-, or -C≡C-; R5 is a carboxy group or a sulfo group (preferably a carboxy group); and R6 and R7 are the same or different and each is a hydrogen atom, an alkyl group, an alkyloxy group, a halogen atom, or a cyano group.) Aspect 5 A liquid crystal polymer film comprising a side-chain liquid crystal polymer having a side-chain structure represented by the following formula (9), wherein the liquid crystal polymer film has a dichroic ratio D of 0.5 or more. [ka] (wherein a is 0 or 1; d and e are the same or different and are an integer of 0 to 2; p is an integer of 0 to 12; q is 0 or 1; X is a single bond, -COO-, -OCO-, or -C≡C-; Q is -CH=N- or -N=CH-; Z2 and Z3 are the same or different and are a single bond, -O-, -COO-, -OCO-, -N=N-, -NO=N-, -CH=CH-, -C≡C-, -CO-CH=CH-, -CH=CH-CO-, -CH=N-, or -N=CH-; R 11 are a hydrogen atom, an alkyl group, an alkyloxy group, a halogen atom, a cyano group, or an amino group; R, R, R 12 , R 13 , R 14 , R 15 , R 16 , and R 17 are the same or different and are a hydrogen atom, an alkyl group, an alkyloxy group, a halogen atom, or a cyano group. Aspect 6 A liquid crystal polymer film comprising a side-chain liquid crystal polymer having a side-chain structure represented by the following formula (10), wherein the liquid crystal polymer film has a dichroic ratio D of 0.5 or more. [ka] (wherein a is 0 or 1; f is an integer of 0 to 3; p is an integer of 0 to 12; q is 0 or 1; X is a single bond, -COO-, -OCO-, or -C≡C-; Z4 is a single bond, -O-, -COO-, -OCO-, -N=N-, -NO=N-, -CH=CH-, -C≡C-, -CO-CH=CH-, -CH=CH-CO-, -CH=N-, or -N=CH-; R 18 are a hydrogen atom, an alkyl group, an alkyloxy group, a halogen atom, a cyano group, or a carboxy group; R, R, R 19 and R 20are the same or different and are a hydrogen atom, an alkyl group, an alkyloxy group, a halogen atom, or a cyano group. Aspect 7 An optically anisotropic element comprising the liquid crystal polymer film according to embodiment 5 or 6. [Effects of the Invention]

[0014] In the present invention, the desired side chain structure can be introduced later by the hydrolysis reaction of the side chain of the photosensitive liquid crystal polymer and the subsequent condensation reaction, which relaxes the constraints on the manufacturing conditions, makes it possible to design the chemical structures of the liquid crystal polymers that make up various liquid crystal polymer films, and produces liquid crystal polymer films with desired physical properties and characteristics.

[0015] Furthermore, the present invention makes it possible to produce a liquid crystal polymer film having improved birefringence and heat resistance, or a liquid crystal polymer film capable of polarized light emission, and the liquid crystal polymer film can be usefully used as an optically anisotropic element. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a graph showing polarized UV-vis absorption spectra of a polymer film after the film formation process and a polymer film after the light irradiation process obtained in Example 1, where (⊥) indicates absorption when the electric field vector of the detection light is oriented vertically, and (||) indicates absorption when the electric field vector of the detection light is oriented parallel. [Figure 2] 1 is a graph showing polarized UV-vis absorption spectra of a polymer film (Initial) after the film formation process, a polymer film (Exposed) after the light irradiation process, and a polymer film (Annealed) after the thermal orientation process, obtained in Example 1, where (⊥) indicates absorption when the electric field vector of the detection light is oriented perpendicularly, and (||) indicates absorption when the electric field vector of the detection light is oriented parallel. [Figure 3]1 is a graph showing polarized UV-vis absorption spectra of a polymer film (Oriented) before the hydrolysis process and a polymer film (After hydrolysis) obtained in Example 1, where (⊥) indicates absorption when the electric field vector of the detection light is oriented vertically, and (||) indicates absorption when the electric field vector of the detection light is oriented parallel. [Figure 4] FIG. 1 is a graph showing polarized UV-vis absorption spectra of the polymer film after the hydrolysis step (Hydrolysis), the polymer film after the coating step (SB coated), and the liquid crystal polymer film after the condensation reaction step (Post annealed) obtained in Example 1, where (⊥) indicates absorption when the electric field vector of the detection light is oriented vertically, and (||) indicates absorption when the electric field vector of the detection light is oriented parallel. [Figure 5] 1 is a graph showing the change in Δn when the liquid crystal polymer film (P1 / SB) obtained in Example 1, the liquid crystal polymer film (P1 / MSB) obtained in Example 2, the liquid crystal polymer film (P1 / FL) obtained in Example 3, and the liquid crystal polymer film (P1 / TD) obtained in Example 4 are heated under a nitrogen atmosphere. DETAILED DESCRIPTION OF THE INVENTION

[0017] (Method of manufacturing liquid crystal polymer film) The method for producing a liquid crystal polymer film of the present invention includes a film-forming step of forming a polymer film containing a side-chain liquid crystal polymer having a mesogen component, a side chain having a hydrolyzable group, and a side chain having a photosensitive group; a light irradiation step of irradiating the obtained polymer film with light capable of causing a photoreaction of the photosensitive groups and anisotropically orienting the mesogen components; a thermal orientation step of heating the light-irradiated polymer film to induce orientation of the unoriented mesogen components; a hydrolysis step of heating the polymer film to hydrolyze the hydrolyzable groups and generate side chain residues together with the elimination compound; a coating step of coating a polymer film with a condensable compound having a condensable group capable of undergoing a condensation reaction with a side chain residue; a condensation reaction step in which a condensation reaction is carried out between the side chain residue and a condensable compound; At least the following is provided.

[0018] [Film formation process] In the film formation step, it is only necessary to form a polymer film containing a side-chain liquid crystal polymer having a mesogen component, a side chain having a hydrolyzable group, and a side chain having a photosensitive group, and the polymer film may be formed by forming a film using a solution containing the side-chain liquid crystal polymer. Alternatively, the polymer film may be formed by forming a film using a solution containing at least two compounds that can be formed by a condensation reaction of the side-chain liquid crystal polymer, and then performing a condensation reaction.

[0019] Side-chain liquid crystal polymers are photosensitive liquid crystal polymers that contain photosensitive groups and mesogen components, which are rigid parts that exhibit liquid crystallinity, and have the property that molecular orientation is induced by the photoreaction of the photosensitive groups. Examples of photoreactions that can be caused by the photosensitive groups include photodimerization, photo-Fries transition, and photoisomerization.

[0020] The photosensitive group is not particularly limited as long as it is a functional group capable of undergoing a photoreaction by light energy, and examples thereof include a chalcone group, a coumarin group, a cinnamoyl group, a cinnamylidene group, a biphenylacryloyl group, a furylacryloyl group, a naphthylacryloyl group, a phenylbenzoate group, a stilbene group, an azobenzene group, a benzylideneaniline group, or a derivative thereof, and preferably a benzylideneaniline group or a derivative thereof.

[0021] The mesogenic component may be a mesogenic group composed of two or more aromatic or aliphatic rings and linking groups connecting them, the linking groups being formed by covalent bonds, or a mesogenic structure formed by dimerization of the linking groups formed by hydrogen bonds, i.e., a structure capable of forming a dimer through hydrogen bonding with another polymer or another side chain of the same polymer. Examples of aromatic rings include a benzene ring, a naphthalene ring, and heterocycles (for example, oxygen-containing heterocycles such as a furan ring and a pyran ring; nitrogen-containing heterocycles such as a pyrrole ring and an imidazole ring). Examples of aliphatic rings include a cyclohexane ring. These aromatic rings or aliphatic rings may have a substituent, and the substituent may be an alkyl group (for example, C 1-6 Alkyl groups, preferably C 1-4 alkyl groups), alkyloxy groups (e.g., C 1-6 Alkyloxy groups, preferably C 1-4 alkyloxy groups), alkenyl groups (e.g., C 2-6 Alkenyl groups, preferably C 2-4 alkenyl groups), alkynyl groups (e.g., C 2-6 Alkynyl groups, preferably C 2-4 alkynyl groups), halogen atoms, etc. Examples of the linking group include, in the case of a covalent bond, a single bond, -O-, -COO-, -OCO-, -N=N-, -NO=N-, -C=C-, -C≡C-, -CO-C=C-, and -CH=N-. In the case of a hydrogen bond, examples include a side chain structure having a carboxy group at the end, in which case a hydrogen bond is formed between the carboxy groups.

[0022] The side-chain liquid crystal polymer has a mesogen component and a side chain having a hydrolyzable group. The hydrolyzable group is a functional group capable of undergoing a hydrolysis reaction, such as an ester group, a thioester group, an acetal group, a ketal group, an amide group, or a Schiff base. From the viewpoint of hydrolysis reactivity, the Schiff base is preferable.

[0023] In a side-chain liquid crystal polymer, the mesogen component and the hydrolyzable group may be present in the same side chain. The photosensitive group may be present in a separate side chain that does not have the mesogen component and the hydrolyzable group, or may be present in the same side chain as the mesogen component and the hydrolyzable group. Preferably, the side-chain liquid crystal polymer may have the mesogen component, the hydrolyzable group, and the photosensitive group in the same side chain. In addition, in the same side chain, the mesogen component, the hydrolyzable group, and the photosensitive group may exist independently, or may exist in a composite manner by sharing a chemical structure. Examples of a case in which the mesogen component, the hydrolyzable group, and the photosensitive group share a chemical structure include a side chain structure having mesogen groups linked by a hydrolyzable group, a side chain structure in which the photosensitive group constitutes part of the mesogen group, a side chain structure in which the hydrolyzable group constitutes part of the photosensitive group, and a side chain structure in which the photosensitive group constitutes part of the mesogen group linked by a hydrolyzable group.

[0024] Preferably, the side-chain liquid crystal polymer may have a side-chain structure in which a photosensitive group constitutes part of a mesogenic group linked by a hydrolyzable group, and more preferably may have a benzylideneaniline group or a derivative thereof in the side chain. The benzylideneaniline group is a photosensitive group whose carbon-nitrogen double bond has photoisomerization reactivity, and also has a rigid molecular structure and is an effective mesogenic group for expressing liquid crystallinity, and the -CH=N- contained in the benzylideneaniline group is also a hydrolyzable group.

[0025] From the viewpoint of maintaining alignment after the hydrolysis reaction, the side-chain liquid crystal polymer may have a mesogen component even after the hydrolyzable group has been hydrolyzed. Examples of side-chain liquid crystal polymers that have a mesogen component even after the hydrolysis reaction include those that have a side chain having a mesogen component and a hydrolyzable group, and that have a side chain having a mesogen component in the residue after the hydrolysis reaction (for example, a side chain having a mesogen component closer to the main chain than the hydrolyzable group), and those that have no hydrolyzable group but have a side chain having a mesogen component.

[0026] The side-chain liquid crystal polymer may have a main chain structure having a linear or cyclic skeletal chain such as a polyacrylate, polymethacrylate, polyvinyl, polysiloxane, polyether, or polymaleimide, and a side chain having a mesogen component and a hydrolyzable group, and a side chain having a photosensitive group may be bonded to this main chain structure.

[0027] The side chains of the side-chain liquid crystal polymer having a mesogen component, a hydrolyzable group, and a photosensitive group may preferably have a side chain structure represented by the following formula (1) (hereinafter, sometimes referred to as side chain structure (1)). <Side chain structure (1)> [ka] In the formula, a is 0 or 1; p is an integer of 0 to 12; q is 0 or 1; X is a single bond, -COO-, -OCO-, or -C≡C-; Q is -CH=N- or -N=CH-; R1, R2, R3, and R4 are the same or different and each is a hydrogen atom, an alkyl group (e.g., C 1-6 Alkyl groups, preferably C 1-4 alkyl groups), alkyloxy groups (e.g., C 1-6 Alkyloxy groups, preferably C 1-4 alkyloxy group), a halogen atom, or a cyano group. R2, R3, and R4 each represent a substituent at a substitutable position on the benzene ring, and may be the same or different from each other at these positions.

[0028] In the side chain structure (1), Q is a Schiff base and connects the benzene rings, resulting in a benzylideneaniline group. As described above, the benzylideneaniline group is a photosensitive group having photoisomerization reactivity and is also a mesogenic group effective in exhibiting liquid crystallinity, and the Schiff base contained in the benzylideneaniline group is a hydrolyzable group.

[0029] The side-chain liquid crystal polymer may be a homopolymer consisting of the same repeating unit containing a side chain having a mesogen component, a hydrolyzable group, and a photosensitive group, or may be a copolymer consisting of repeating units containing a mesogen component, a side chain having a hydrolyzable group, and a side chain having a photosensitive group, or a copolymer containing repeating units containing a side chain structure different from these side chains.

[0030] When the side chain liquid crystal polymer is a copolymer, it may have a side chain that does not have a mesogen component, a hydrolyzable group, and / or a photosensitive group.

[0031] For example, the side-chain liquid crystal polymer may further have a side chain having a functional group that has catalytic activity for the hydrolysis reaction at the hydrolyzable group of the side chain. Examples of the functional group that has catalytic activity for the hydrolysis reaction include acidic functional groups such as a carboxy group and a sulfo group, and preferably a carboxy group. By having a functional group that has catalytic activity for the hydrolysis reaction, the hydrolysis reaction can be carried out on the side chain without the need for a separate addition of a catalyst such as an acid in the hydrolysis step described below. Furthermore, a step for removing the catalyst such as an acid is also not required, simplifying the method for producing a liquid crystal polymer film.

[0032] The side chain type liquid crystal polymer may have a side chain having a side chain structure represented by the following formula (2) (hereinafter, sometimes referred to as side chain structure (2)) as a side chain having a functional group that has catalytic activity for the hydrolysis reaction of the hydrolyzable group. <Side chain structure (2)> [ka] In the formula, b is 0 or 1; r is an integer of 0 to 12; s is 0 or 1; Y is a single bond, -COO-, -OCO-, or -C≡C-; R5 is a carboxy group or a sulfo group (preferably a carboxy group); R6 and R7 are the same or different and each is a hydrogen atom, an alkyl group (e.g., C 1-6 Alkyl groups, preferably C 1-4 alkyl groups), alkyloxy groups (e.g., C 1-6Alkyloxy groups, preferably C 1-4 alkyloxy group), a halogen atom, or a cyano group. R6 and R7 each represent a substituent at a substitutable position on the benzene ring, and may be the same or different from each other at these positions.

[0033] In the above formula (2), R5 is a carboxyl group or sulfo group, which is an acidic functional group, and is therefore a functional group that has catalytic activity in hydrolysis reactions, preferably a carboxyl group. In the above formula (2), when R5 is a carboxyl group, in addition to acting as a catalyst in hydrolysis reactions, the carboxyl group has hydrogen-bonding properties, and therefore it is possible to form a mesogenic structure by dimerizing through hydrogen bonds with a carboxyl group, such as a terminal benzoic acid group, of a side chain of another polymer or the same polymer. That is, in the above formula (2), when R5 is a carboxyl group, the polymer has a mesogenic component even if b is 0.

[0034] The side chain structures (1) and (2) represent the chemical structures at the ends of the side chains in the repeating units, and various chemical structures may be included between these side chain structures and the main chain structure as long as the effects of the present invention are not impaired.

[0035] When the side chain liquid crystal polymer is a copolymer having side chain structures (1) and (2), the molar ratio (1) / (2) of the monomer unit having side chain structure (1) to the monomer unit having side chain structure (2) may be 1 / 99 to 50 / 50, preferably 2 / 98 to 40 / 60, and more preferably 5 / 95 to 30 / 70, from the viewpoint of adjusting the liquid crystal temperature range.

[0036] In the film formation process, the material used to form the polymer film may contain the side-chain liquid crystal polymer described above, and may further contain other compounds. Such compounds may be either high molecular weight compounds or low molecular weight compounds. For example, the material may contain a polymer having a side chain with a functional group that has catalytic activity in a hydrolysis reaction, preferably a polymer having a side chain with the side chain structure (2). In particular, when R5 in the above formula (2) is a carboxy group, it not only acts as a catalyst for the hydrolysis reaction of the side chain of the side-chain liquid crystal polymer, but also forms a mesogenic structure by forming hydrogen bonds and dimerizing, thereby exhibiting liquid crystallinity.

[0037] The method for producing the side chain liquid crystal polymer is not particularly limited, and the polymer can be produced by a known polymerization method using a monomer having the above-mentioned side chain.

[0038] The side-chain liquid crystal polymer can be produced by condensing at least two compounds capable of forming the side-chain liquid crystal polymer. The condensation reaction is a chemical reaction between functional groups of at least two compounds, resulting in the elimination of molecules such as water, alcohols, ammonia, amines, and hydrogen halides. Such compounds may include at least a polymer compound (precursor polymer compound) capable of forming the side-chain liquid crystal polymer by condensation and a low-molecular-weight compound. The precursor polymer compound and the low-molecular-weight compound each have a condensable group capable of condensation reaction with each other. The precursor polymer compound has a side chain having a condensable group. The precursor polymer compound does not have at least one of a mesogen component, a hydrolyzable group, and a photosensitive group. The precursor polymer compound may undergo a condensation reaction with the low-molecular-weight compound to form a side chain having a mesogen component and a hydrolyzable group, as well as a side chain having a photosensitive group.

[0039] For example, the side chain having a condensable group of the precursor polymer compound may not have at least a hydrolyzable group, but may be capable of introducing a hydrolyzable group by a condensation reaction, and preferably the group formed by the condensation reaction may be a hydrolyzable group. Furthermore, the side chain may have a photosensitive group or a condensable group capable of introducing a photosensitive group by a condensation reaction. Furthermore, the side chain may have a mesogen component or a condensable group capable of introducing a mesogen component by a condensation reaction.

[0040] Examples of the condensable group include a hydroxy group, an aldehyde group, an amino group, and a carboxy group, and preferably an aldehyde group or an amino group. For example, the condensable group of the side chain of the precursor polymer compound and the condensable group of the low molecular weight compound may be an aldehyde group and an amino group, respectively, and preferably an aromatic aldehyde group and an aromatic amino group, respectively. The aromatic aldehyde group and the aromatic amino group form a benzylideneaniline group by a dehydration condensation reaction as shown in Reaction Scheme 1 below. [ka]

[0041] The side chain having a condensable group of the precursor polymer compound may preferably have a side chain structure represented by the following formula (3) (hereinafter, sometimes referred to as side chain structure (3)) as a precursor of the side chain structure represented by the above formula (1) of the side chain type liquid crystal polymer. <Side chain structure (3)> [ka] In the formula, a is 0 or 1; p is an integer of 0 to 12; q is 0 or 1; X is a single bond, -COO-, -OCO-, or -C≡C-; Q1 is an aldehyde group or an amino group; R2 and R3 are the same or different and each is a hydrogen atom, an alkyl group (e.g., C 1-6 Alkyl groups, preferably C 1-4 alkyl groups), alkyloxy groups (e.g., C 1-6 Alkyloxy groups, preferably C 1-4R2 and R3 each represent a substituent at a substitutable position on the benzene ring, and may be the same or different from each other.

[0042] The precursor polymer compound may have a side chain corresponding to the side-chain liquid crystal polymer, or in the case of a copolymer, may have a side chain that does not contribute to the condensation reaction. For example, it may have a side chain that does not have a mesogen component, a hydrolyzable group, and / or a photosensitive group, or it may have a side chain that has a functional group that has catalytic activity in the hydrolysis reaction, preferably a side chain having the side chain structure (2).

[0043] The side chain structure (3), like the corresponding side chain structure (1) after the condensation reaction, represents the chemical structure at the end of the side chain in the repeating unit, and various chemical structures may be included between this side chain structure and the main chain structure as long as the effects of the present invention are not impaired.

[0044] When the precursor polymer compound is a copolymer having side chain structures (3) and (2), from the viewpoint of adjusting the liquid crystal temperature range, the molar ratio (3) / (2) of the monomer unit having the side chain structure (3) to the monomer unit having the side chain structure (2) may be 1 / 99 to 50 / 50, preferably 2 / 98 to 40 / 60, and more preferably 5 / 95 to 30 / 70.

[0045] The method for producing the precursor polymer compound is not particularly limited, and the compound can be produced by a known polymerization method using a monomer having the above-mentioned side chain.

[0046] When the low molecular weight compound having a condensable group remains as an unreacted substance after the condensation reaction, it is preferable that it can be easily removed from the system by evaporation, sublimation, washing, etc., and more preferably, it may be a sublimable low molecular weight compound. If it is a sublimable low molecular weight compound, it can be removed by heating in the thermal orientation step or hydrolysis step described below, and it can be prevented from remaining until the subsequent condensation reaction step and contributing again to the condensation reaction.

[0047] The low molecular weight compound having a condensable group may preferably be a compound represented by the following formula (4) (hereinafter, sometimes referred to as low molecular weight compound (4)). <Low molecular compound (4)> [ka] In the formula, Q2 is an amino group or an aldehyde group; R1 and R4 are the same or different and each is a hydrogen atom, an alkyl group (e.g., C 1-6 Alkyl groups, preferably C 1-4 alkyl groups), alkyloxy groups (e.g., C 1-6 Alkyloxy groups, preferably C 1-4 alkyloxy group), a halogen atom, or a cyano group. R4 represents a substituent at a substitutable position on the benzene ring, and may be the same or different substituents at these positions.

[0048] The low molecular weight compound having a condensable group may have a molecular weight of, for example, 50 to 500, preferably 90 to 300, and more preferably 110 to 200. Examples of the low molecular weight compound having a condensable group include sublimable compounds such as p-anisidine (4-methoxyaniline).

[0049] In the film formation process, a polymer film may be formed by forming a film using a solution in which the side-chain liquid crystal polymer is dissolved in an organic solvent, or by forming a film using a solution (mixed solution) in which at least two compounds capable of forming the side-chain liquid crystal polymer by a condensation reaction are dissolved in an organic solvent, or by forming individual solutions (single solutions) in which these compounds are dissolved in an organic solvent, followed by a condensation reaction to form a polymer film. In the case of a single solution, films are formed individually, but in order to perform a condensation reaction between the compounds, the solutions of each compound are formed so that there is at least an overlapping portion.

[0050] The organic solvent can be appropriately selected depending on the type of side-chain liquid crystal polymer or compound to be dissolved. Non-halogenated solvents are preferred. Examples include alcoholic solvents such as ethanol, propanol, and butanol; ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, and cyclopentanone; ester solvents such as ethyl acetate, butyl acetate, and methoxypropyl acetate; ether solvents such as diethyl ether, tetrahydrofuran, dioxane, ethylene glycol monoethyl ether, diethylene glycol monoethyl ether, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, propylene glycol monomethyl ether, and propylene glycol 1-monomethyl ether 2-acetate; hydrocarbon solvents such as hexane, cyclohexane, methylcyclohexane, toluene, and xylene; nitrile solvents such as acetonitrile; and amide solvents such as N-methylpyrrolidone and dimethylacetamide. These solvents may be used alone or in combination. In the present invention, the chemical structure of the side-chain liquid crystal polymer can be designed to suit the orientation and manufacturing conditions, thereby broadening the options for solvents for side-chain liquid crystal polymers. Furthermore, when a polymer film is used as the substrate, as will be described later, a solvent can be selected that is a good solvent for the side-chain liquid crystal polymer and does not dissolve the polymer film.

[0051] During film formation, the solution may be applied to a substrate. Substrates may be selected from various polymer films and inorganic materials such as glass and quartz substrates. Examples of polymer films include polyester films such as polyethylene terephthalate; acrylic resin films such as polymethyl methacrylate; cellulose polymer films such as diacetyl cellulose and triacetyl cellulose; polycarbonate polymer films such as bisphenol A-carbonate copolymers; linear, branched, or cyclic polyolefin films such as polyethylene, polypropylene, ethylene-propylene copolymers, cycloolefin polymers, and cycloolefin copolymers; polyamide films; imide polymer films; and sulfone polymer films. When using a liquid crystal polymer film in an optically anisotropic element, a transparent substrate among the above substrates may be used as part of the optically anisotropic element.

[0052] In addition, among the above substrates, a substrate made of a material having low adhesion to the liquid crystal polymer film of the present invention may be used as a release substrate.When a release substrate is used, since it can be peeled off after the liquid crystal polymer film of the present invention is formed, the optical properties of the substrate itself do not need to be considered, and an opaque substrate may be used.For example, after the liquid crystal polymer film of the present invention is formed on the substrate, it is bonded to another optical component via an adhesive or the like, and then the release substrate is peeled off and used, so that the liquid crystal polymer film can be used as a configuration without a substrate.

[0053] As a film formation method, known methods can be used, for example, coating / printing methods such as gravure coating, flexo coating, die coating, bar coating, slit coating, spin coating, knife coating, spray coating, and screen printing, and direct drawing methods using an inkjet printer.

[0054] Furthermore, when at least two kinds of compounds (e.g., a precursor polymer compound and a low molecular weight compound) capable of forming the above-mentioned side-chain liquid crystal polymer by a condensation reaction are dissolved in a solvent and the resulting solutions (single solutions) are separately formed into films, for example, one of the compounds may be applied to the entire surface to form a film, and the other compound may be patterned and applied using a printing method or a printer, so that only the area where the other compound is applied forms a side-chain liquid crystal polymer, which is then oriented to form an optically anisotropic layer.

[0055] Furthermore, when the film-forming solutions of the precursor polymer compound and the low molecular weight compound are applied separately, it is preferable to first apply the precursor polymer compound solution and then apply the low molecular weight compound solution to the precursor polymer compound coating film, since this allows the low molecular weight compound to efficiently adhere to the precursor polymer compound.

[0056] The conditions for the condensation reaction of at least two compounds capable of forming the side-chain liquid crystal polymer by condensation reaction can be appropriately set depending on the type of compound. The condensation reaction may be carried out at room temperature or under heating. Heating can accelerate the condensation reaction. The heating temperature is preferably set to a temperature equal to or lower than the boiling point or sublimation point of each compound.

[0057] The time for the condensation reaction can be appropriately set depending on the type of compound, reaction conditions such as heating temperature, etc. For example, when heated at a predetermined temperature, the time for the condensation reaction may be, for example, in the range of 1 minute to 60 minutes, preferably about 3 minutes to 40 minutes, and more preferably about 5 minutes to 20 minutes.

[0058] [Light irradiation process] In the light irradiation step, the polymer film obtained in the film formation step is irradiated with light that can photoreact with the photosensitive groups in the side chains of the side-chain liquid crystal polymer and anisotropically align the mesogen components. Such light may be linearly polarized or elliptically polarized, but linearly polarized light is preferred. The light irradiation step results in a polymer film that exhibits anisotropy due to an axially selective photoreaction.

[0059] The light to be irradiated may be infrared, visible light, ultraviolet (e.g., near ultraviolet, far ultraviolet, etc.), X-ray, charged particle beam (e.g., electron beam, etc.), or the like, as long as it has a wavelength that causes a photoreaction of the photosensitive group of the side-chain liquid crystal polymer. Although the wavelength of the light varies depending on the side chain structure of the side-chain liquid crystal polymer, it can be appropriately set depending on the type of photosensitive group, and may be 200 to 500 nm, with 250 to 400 nm being particularly effective in many cases. Examples of photoreactions include photodimerization reactions, photo-Fries transition reactions, and photoisomerization reactions, with photoisomerization reactions being preferred.

[0060] The amount of light irradiation is not particularly limited as long as it can generate anisotropy through an axis-selective photoreaction. For example, 2 ~150J / cm 2 and preferably 500 mJ / cm 2 ~100J / cm 2 , more preferably 1 J / cm 2 ~50J / cm 2 may be.

[0061] For example, when benzylidene aniline groups are irradiated with linearly polarized light, they undergo axially selective cis-trans photoisomerization, as shown in the following reaction formula 2. When a polymer film containing a side-chain liquid crystal polymer containing benzylidene aniline groups is irradiated with polarized ultraviolet light, the film becomes anisotropic due to axially selective photoisomerization. [ka]

[0062] [Thermal orientation process] In the thermal orientation process, the polymer film irradiated in the light irradiation process is heated. When the polymer film, which has become anisotropic due to the axially selective photoreaction, is heated, the side-chain liquid crystalline polymers in the polymer film become able to undergo molecular motion. Because the material itself has liquid crystal properties, the molecular motion cooperatively induces the alignment of the unoriented mesogen components along the side chains that have undergone the photoreaction.

[0063] When molecular orientation occurs due to a photoreaction such as the cis-trans photoisomerization reaction described above, the orientation of the unoriented mesogen components is cooperatively induced along the molecular orientation, resulting in a film in which the side chains are uniformly oriented in the direction perpendicular to the electric field vibration direction of the irradiated polarized light component (e.g., linearly polarized light) throughout the entire polymer film, amplifying the anisotropy of the polymer film itself. This amplification of anisotropy results in optical anisotropy (birefringence).

[0064] The heating temperature is not particularly limited as long as it induces cooperative molecular orientation of the side-chain liquid crystal polymer in the polymer film, but is preferably set to a temperature equal to or higher than the liquid crystal phase transition temperature of the material (side-chain liquid crystal polymer) forming the polymer film itself and lower than the isotropic phase transition temperature. For example, the temperature may be 80 to 300°C, preferably 100 to 280°C, and more preferably 110 to 250°C.

[0065] The heating time is not particularly limited as long as it induces cooperative molecular orientation of the side-chain liquid crystal polymer in the polymer film, but can be appropriately set depending on the type of side-chain liquid crystal polymer, heating temperature, etc. For example, it may be 1 minute or more, preferably 3 minutes or more, more preferably 5 minutes or more. The upper limit is not particularly limited, but from an economical viewpoint, it may be about 60 minutes (preferably about 40 minutes, more preferably about 20 minutes).

[0066] [Hydrolysis process] In the hydrolysis step, the polymer film is heated to hydrolyze the hydrolyzable groups in the side chains of the side-chain liquid crystal polymer, thereby generating side-chain residues along with the elimination compound. In the present invention, the condensable groups in the side-chain residues generated by hydrolyzing the hydrolyzable groups in the side chains of the side-chain liquid crystal polymer can be used to introduce the structure of a condensable compound into the side chains in the condensation reaction step described below. Furthermore, even if the hydrolysis reaction occurs in the hydrolysis step, the orientation of the mesogenic component of the side-chain liquid crystal polymer can be maintained, possibly because it is fixed by the light irradiation step and the heat orientation step. Therefore, even if the side chain of a side-chain liquid crystal polymer into which a condensable compound described below has been introduced has a chemical structure that is inherently difficult to photoalign, a liquid crystal polymer film containing a side-chain liquid crystal polymer with a desired side-chain structure and orientation can be produced.

[0067] In the hydrolysis step, the rate at which the hydrolysis reaction occurs in the hydrolyzable groups of the side-chain liquid crystal polymer (hydrolysis rate) can be adjusted by adjusting the heating conditions. Therefore, it is possible to leave the side chain structure of the original side-chain liquid crystal polymer and adjust the introduction rate of the condensable compound described below.

[0068] The cleaved compound from the side chain liquid crystal polymer by the hydrolysis reaction is preferably one that can be easily removed from the system by evaporation, sublimation, washing, etc., and examples thereof include sublimable low molecular weight compounds.

[0069] The heating temperature is not particularly limited as long as it is possible to promote the hydrolysis reaction and adjust the hydrolysis rate. However, from the viewpoint of maintaining the alignment of the side chains of the side-chain liquid crystal polymer, it is preferable to set the temperature below the isotropic phase transition temperature of the material (liquid crystal polymer) that forms the film itself. Furthermore, to prevent the elimination compound from participating in the condensation reaction process described below, it is preferable to set the temperature at which the elimination compound sublimes and evaporates. The heating temperature varies depending on the structure of the side chains containing hydrolyzable groups of the side-chain liquid crystal polymer and the presence or absence of functional groups that have catalytic activity in the hydrolysis reaction. For example, it may be 80 to 180°C, preferably 90 to 160°C, and more preferably 100 to 150°C.

[0070] The hydrolysis step may be carried out in an air atmosphere or a humid atmosphere from the viewpoint of promoting the hydrolysis reaction. The humidity in the hydrolysis step may be, for example, 20% RH or higher, preferably 30% RH or higher. The upper limit is not particularly limited, but may be about 95% RH (preferably about 90% RH).

[0071] The heating time can be appropriately set depending on the structure of the side chain having a hydrolyzable group of the side-chain liquid crystal polymer, the heating temperature, etc., and may be, for example, 5 minutes or more, preferably 20 minutes or more, and more preferably 30 minutes or more. The upper limit is not particularly limited, but from the viewpoint of economy, it may be about 600 minutes (preferably about 180 minutes, more preferably about 120 minutes).

[0072] In the above-described production method, the thermal orientation step and the hydrolysis step may be carried out simultaneously by heating. By carrying out the thermal orientation step and the hydrolysis step simultaneously, molecular orientation and hydrolysis reaction can be carried out efficiently.

[0073] Furthermore, after the hydrolysis step, if the polymer film in which the rigid portions are oriented is cooled to a temperature below the softening point of the material, the molecules are frozen, and a polymer film in which the rigid portions are oriented is obtained. Cooling is preferably performed by leaving the polymer film to cool as usual.

[0074] [Coating process] In the coating step, a condensable compound having a condensable group capable of undergoing a condensation reaction with the side chain residues generated in the hydrolysis step is coated onto the polymer film. The condensable compound is preferably a compound different from the elimination compound. For example, from the viewpoint of improving birefringence and heat resistance, the condensation compound preferably has a larger molecular weight than the elimination compound. Furthermore, from the viewpoint of improving the reaction efficiency between the side chain residues and the condensation compound, it is preferable that the elimination compound is a compound that evaporates or sublimes at the heating temperature in the hydrolysis step and can be easily removed from the system by evaporation, sublimation, or the like in the hydrolysis step, while it is preferable that the condensable compound is a compound that does not evaporate or sublimate at the reaction temperature in the condensation reaction step described below.

[0075] The condensable group of the condensable compound is not particularly limited as long as it can undergo a condensation reaction with the condensable group of the side chain residue generated by hydrolysis, and examples thereof include a hydroxy group, an aldehyde group, an amino group, a carboxy group, etc., and preferably an aldehyde group or an amino group. For example, as the condensable group of the side chain residue and the low molecular weight compound, an aldehyde group and an amino group may be combined, and preferably an aromatic aldehyde group and an aromatic amino group may be combined, and these can form a benzylideneaniline group by a dehydration condensation reaction as described above.

[0076] The condensable compound may have a chemical structure that allows the introduction of a mesogen component and / or a photosensitive group through a condensation reaction with a side chain residue.

[0077] The condensable group of the side chain residue is an aldehyde group or an amino group, and the condensable compound is preferably at least one compound selected from the group consisting of compounds represented by the following formulas (5) to (7) (hereinafter, sometimes referred to as condensable compounds (5) to (7)).

[0078] <Condensation compound (5)> [ka] In the formula, c is an integer of 0 to 3 (preferably 1 to 3); Z1 is a single bond, -O-, -COO-, -OCO-, -N=N-, -NO=N-, -CH=CH-, -C≡C-, -CO-CH=CH-, -CH=CH-CO-, -CH=N-, or -N=CH-; Q3 is -NH2 or -CHO; R8 is a hydrogen atom, an alkyl group (e.g., C 1-6 Alkyl groups, preferably C 1-4 alkyl groups), alkyloxy groups (e.g., C 1-6 Alkyloxy groups, preferably C 1-4 alkyloxy group), halogen atom, cyano group, amino group, aldehyde group, carboxy group, or cinnamic acid group; R and R 10are the same or different and may be hydrogen atoms, alkyl groups (e.g., C 1-6 Alkyl groups, preferably C 1-4 alkyl groups), alkyloxy groups (e.g., C 1-6 Alkyloxy groups, preferably C 1-4 alkyloxy group), a halogen atom, or a cyano group. 10 Each represents a substituent at a substitutable position on the benzene ring, and represents the same or different substituents at these positions. In the above formula (5), when c is 2 or 3, multiple chemical structures in parentheses are bonded, and their Z1 and R 10 may be the same or different.

[0079] In the above formula (5), when the condensable group of the side chain residue is an aldehyde group, Q3 is -NH2, and when the condensable group of the side chain residue is an amino group, Q3 is -CHO, both of which form a Schiff base by condensation reaction.

[0080] In the condensable compound (5), c is preferably an integer of 1 to 3 in the above formula (5), from the viewpoint of improving the birefringence and heat resistance of the side chain liquid crystal polymer obtained by condensation.

[0081] In the condensable compound (5) of the above formula (5), when Q3 is -NH2 and R8 is an amino group, both can undergo a condensation reaction with the aldehyde group of the side chain residue, and crosslinking can occur when the condensation reaction occurs with both amino groups. Also, when Q3 is -CHO and R8 is an aldehyde group, both can undergo a condensation reaction with the amino group of the side chain residue, and crosslinking can occur when the condensation reaction occurs with both aldehyde groups. In such cases, crosslinking can improve heat resistance.

[0082] <Condensation compound (6)> [ka] In the formula, d and e are the same or different and are integers of 0 to 2; Z2 and Z3 are the same or different and are a single bond, -O-, -COO-, -OCO-, -N=N-, -NO=N-, -CH=CH-, -C≡C-, -CO-CH=CH-, -CH=CH-CO-, -CH=N-, or -N=CH-; Q4 is -NH2 or -CHO; R 11 represents a hydrogen atom, an alkyl group (e.g., C 1-6 Alkyl groups, preferably C 1-4 alkyl groups), alkyloxy groups (e.g., C 1-6 Alkyloxy groups, preferably C 1-4 alkyloxy group), halogen atom, cyano group, amino group, or aldehyde group; R 12 , R 13 , R 14 , R 15 , R 16 , and R 17 are the same or different and may be hydrogen atoms, alkyl groups (e.g., C 1-6 Alkyl groups, preferably C 1-4 alkyl groups), alkyloxy groups (e.g., C 1-6 Alkyloxy groups, preferably C 1-4 alkyloxy group), halogen atom, or cyano group. 12 , R 13 , R 14 , and R 15 Each represents a substituent at a substitutable position on the benzene ring, and these positions may be the same or different. When d and e are 2, multiple chemical structures in parentheses are bonded, and their Z2 and R 12 and Z3 and R 15 may be the same or different.

[0083] The condensable compound (6) has a fluorene skeleton and can improve the birefringence and heat resistance of the side-chain liquid crystal polymer obtained by condensation.

[0084] In the above formula (6), when the condensable group of the side chain residue is an aldehyde group, Q4 is -NH2, and when the condensable group of the side chain residue is an amino group, Q4 is -CHO, both of which form a Schiff base by condensation reaction.

[0085] The condensable compound (6) is a compound represented by the above formula (6), in which Q4 is -NH2 and R 11 When R is an amino group, both can undergo condensation reaction with the aldehyde group of the side chain residue, and crosslinking can be achieved by condensation reaction with both amino groups. 11 When is an aldehyde group, both can undergo a condensation reaction with the amino group of the side chain residue, and crosslinking can occur when the condensation reaction occurs with both aldehyde groups. In such cases, crosslinking can improve heat resistance.

[0086] <Condensation compound (7)> [ka] In the formula, f is an integer of 0 to 3; Z4 is a single bond, -O-, -COO-, -OCO-, -N=N-, -NO=N-, -CH=CH-, -C≡C-, -CO-CH=CH-, -CH=CH-CO-, -CH=N-, or -N=CH-; R 18 represents a hydrogen atom, an alkyl group (e.g., C 1-6 Alkyl groups, preferably C 1-4 alkyl groups), alkyloxy groups (e.g., C 1-6 Alkyloxy groups, preferably C 1-4 alkyloxy group), halogen atom, cyano group, or carboxy group; R 19 and R 20 are the same or different and may be hydrogen atoms, alkyl groups (e.g., C 1-6 Alkyl groups, preferably C 1-4 alkyl groups), alkyloxy groups (e.g., C 1-6 Alkyloxy groups, preferably C 1-4 alkyloxy group), halogen atom, or cyano group. 19 and R 20Each represents a substituent at a substitutable position on the benzene ring, and these positions may be the same or different. When f is 2 or 3, multiple chemical structures in parentheses are bonded, and their Z4 and R 20 may be the same or different.

[0087] The side chain structure introduced by the condensation reaction using the condensable compound (7) is a chemical structure that is difficult to photoalign, and therefore it is difficult to prepare an optically anisotropic liquid crystal polymer film using a side chain liquid crystal polymer having such a side chain structure as a raw material. However, the production method of the present invention makes it possible to prepare an optically anisotropic liquid crystal polymer film containing a side chain liquid crystal polymer having such a side chain structure.

[0088] When condensable compound (7) is used, the condensable group of the side chain residue is an amino group, which forms a Schiff base by condensation with the aldehyde group of formula (7) above. When the condensable group of the side chain residue is an aromatic amino group, a salicylideneaniline derivative can be formed by condensation with condensable compound (7). When irradiated with ultraviolet light, the salicylideneaniline derivative undergoes phototautomerization due to intramolecular hydrogen transfer, as shown in reaction formula 3 below, and can emit polarized light. [ka]

[0089] In the coating step, the condensable compound may be applied as is if it is a liquid, or may be applied as a solution if it is a solid. The condensable compound is applied so that there is at least an overlap with the hydrolyzed side-chain liquid crystal polymer in the polymer film. The coating method can utilize the film-forming method described in the film-forming step above. By performing patterned coating using a printing method or a printer, it is possible to form a side-chain liquid crystal polymer into which the condensable compound is introduced by a condensation reaction only in the area where the condensable compound is applied, and to form an optically anisotropic layer with different optical properties from the area where the condensable compound is not applied.

[0090] The coating step may be carried out before the hydrolysis step. In this case, the hydrolysis step and the condensation reaction step described below may be carried out simultaneously. The hydrolysis produces a elimination compound, and the side chain residue having a condensable group can undergo a condensation reaction with the condensable compound.

[0091] [Condensation reaction step] In the condensation reaction step, a condensation reaction is carried out between the side chain residue and the condensable compound. The condensation reaction step allows the introduction of a desired side chain structure into the side chain liquid crystal polymer, thereby obtaining a liquid crystal polymer film with desired physical properties and characteristics. For example, the physical properties (e.g., birefringence, heat resistance, etc.) can be improved compared to the polymer film before the hydrolysis step, or properties (e.g., polarized luminescence) that the polymer film did not have before the hydrolysis step can be imparted.

[0092] The condensation reaction step may be carried out at room temperature or under heating. Heating can accelerate the condensation reaction. The heating temperature is preferably set to a temperature equal to or lower than the boiling point or sublimation point of the condensable compound. For example, the heating temperature may be 50 to 180°C, preferably 80 to 160°C, and more preferably 100 to 140°C.

[0093] The time for the condensation reaction can be appropriately set depending on the type of condensable compound, reaction conditions such as heating temperature, etc. For example, when heated at a predetermined temperature, the time for the condensation reaction may be, for example, in the range of 1 minute to 120 minutes, preferably about 3 minutes to 90 minutes, and more preferably about 5 minutes to 60 minutes.

[0094] As described above, in the method for producing a liquid crystal polymer film of the present invention, while maintaining the orientation of the side chain liquid crystal polymer induced by the light irradiation step and the heat orientation step, a desired side chain structure can be introduced later by the hydrolysis reaction of the side chain of the side chain liquid crystal polymer and the subsequent condensation reaction. Therefore, restrictions on the production conditions can be suppressed regardless of the chemical structure of the side chain liquid crystal polymer that constitutes the final liquid crystal polymer film, and a liquid crystal polymer film having predetermined physical properties and characteristics can be produced.

[0095] (liquid crystal polymer film) The liquid crystal polymer film of the present invention can be obtained by the above-mentioned production method, and may be a liquid crystal polymer film composed of a side-chain liquid crystal polymer formed by introducing a condensation compound, in which the orientation induced by the above-mentioned light irradiation step and heat orientation step is maintained. The liquid crystal polymer film of the present invention preferably has predetermined physical properties and characteristics, and for example, may have improved physical properties (e.g., birefringence, heat resistance, etc.) compared to the polymer film before the hydrolysis step, or may have characteristics (e.g., polarized luminescence) that the polymer film before the hydrolysis step did not have.

[0096] The liquid crystal polymer film of the present invention may have a dichroic ratio D of 0.5 or more. The dichroic ratio D is a parameter that quantifies polarization characteristics, and is defined by the following formula. D=(A⊥-A||) / (A⊥+A||) In the formula, A⊥ represents the absorbance when the electric field vectors of the irradiated polarized UV light and the detection light during polarized UV-vis spectrum measurement are perpendicular, and A|| represents the absorbance when the electric field vectors of the irradiated polarized UV light and the detection light during polarized UV-vis spectrum measurement are perpendicular.

[0097] The higher the dichroic ratio D, the higher the molecular orientation. The liquid crystal polymer film of the present invention can maintain the orientation induced by the light irradiation step and the thermal orientation step, even if the mesogenic side chains are subjected to hydrolysis and condensation reactions. The dichroic ratio D is preferably 0.55 or more, more preferably 0.6 or more. The upper limit of the dichroic ratio D is not particularly limited, but it may be 1 or less. The dichroic ratio D is a measurement value of absorption at the same wavelength measured in a polarized absorption spectrum. The wavelength is appropriately selected depending on the chemical structure, and may be a measurement value of absorption at the wavelength showing the highest D value.

[0098] From the viewpoint of controlling optical anisotropy, the liquid crystal polymer film of the present invention may have a birefringence Δn of 0.13 or more, preferably 0.14 or more, more preferably 0.15 or more. The upper limit of Δn is not particularly limited, but may be, for example, 1 or less.

[0099] In the present invention, the maximum temperature at which no change in Δn occurs when the temperature of the liquid crystal polymer film is increased is defined as the heat resistance temperature (TS), and the liquid crystal polymer film of the present invention may have a TS of 150° C. or higher, preferably 155° C. or higher, and more preferably 160° C. or higher. The upper limit of TS is not particularly limited, but may be, for example, 400° C. or lower.

[0100] For example, the liquid crystal polymer film of the present invention may contain a side chain liquid crystal polymer having a side chain structure represented by the following formula (8) (hereinafter, sometimes referred to as side chain structure (8)). <Side chain structure (8)> [ka] In the formula, a is 0 or 1; c is an integer of 0 to 3 (preferably 1 to 3); p is an integer of 0 to 12; q is 0 or 1; X is a single bond, -COO-, -OCO-, or -C≡C-; Q is -CH=N- or -N=CH-; Z1 is a single bond, -O-, -COO-, -OCO-, -N=N-, -NO=N-, -CH=CH-, -C≡C-, -CO-CH=CH-, -CH=CH-CO-, -CH=N-, or -N=CH-; R8 is a hydrogen atom, an alkyl group (e.g., C 1-6 Alkyl groups, preferably C 1-4 alkyl groups), alkyloxy groups (e.g., C 1-6 Alkyloxy groups, preferably C 1-4 alkyloxy group), halogen atom, cyano group, amino group, aldehyde group, carboxy group, or cinnamic acid group; R2, R3, R9 and R 10 are the same or different and may be hydrogen atoms, alkyl groups (e.g., C 1-6 Alkyl groups, preferably C 1-4 alkyl groups), alkyloxy groups (e.g., C 1-6 Alkyloxy groups, preferably C 1-4 alkyloxy group), a halogen atom, or a cyano group. 10Each represents a substituent at a substitutable position on the benzene ring, and these positions may be the same or different. When c is 2 or 3, multiple chemical structures in parentheses are bonded, and their Z1 and R 10 may be the same or different.

[0101] In order to improve the birefringence and heat resistance of the liquid crystal polymer film of the present invention, a side chain liquid crystal polymer in which c is an integer of 1 to 3 in the above formula (8) is preferred.

[0102] In the liquid crystal polymer film of the present invention, when the side chain type liquid crystal polymer in the above formula (8) is a side chain type liquid crystal polymer in which Q is -CH=N- and R8 is an amino group, and when Q is -N=CH- and R8 is an aldehyde group, some of the side chains contain side chains in which the amino group or aldehyde group of R8 also undergoes a condensation reaction with the side chain residue when a condensable compound is introduced to form a crosslinked structure, and therefore such side chain type liquid crystal polymers are preferred because they can improve heat resistance.

[0103] For example, the liquid crystal polymer film of the present invention may contain a side chain liquid crystal polymer having a side chain structure represented by the following formula (9) (hereinafter, sometimes referred to as side chain structure (9)). <Side chain structure (9)> [ka] In the formula, a is 0 or 1; d and e are the same or different and are an integer of 0 to 2; p is an integer of 0 to 12; q is 0 or 1; X is a single bond, -COO-, -OCO-, or -C≡C-; Q is -CH=N- or -N=CH-; Z2 and Z3 are the same or different and are a single bond, -O-, -COO-, -OCO-, -N=N-, -NO=N-, -CH=CH-, -C≡C-, -CO-CH=CH-, -CH=CH-CO-, -CH=N-, or -N=CH-; R 11 represents a hydrogen atom, an alkyl group (e.g., C 1-6 Alkyl groups, preferably C 1-4 alkyl groups), alkyloxy groups (e.g., C 1-6Alkyloxy groups, preferably C 1-4 alkyloxy group), halogen atom, cyano group, amino group, or aldehyde group; R2, R3, R 12 , R 13 , R 14 , R 15 , R 16 , and R 17 are the same or different and may be hydrogen atoms, alkyl groups (e.g., C 1-6 Alkyl groups, preferably C 1-4 alkyl groups), alkyloxy groups (e.g., C 1-6 Alkyloxy groups, preferably C 1-4 alkyloxy group), halogen atom, or cyano group. 12 , R 13 , R 14 , and R 15 Each represents a substituent at a substitutable position on the benzene ring, and these positions may be the same or different. When d and e are 2, multiple chemical structures in parentheses are bonded, and their Z2 and R 12 and Z3 and R 15 may be the same or different.

[0104] The side-chain liquid crystal polymer having the side-chain structure (9) has a fluorene skeleton, and can improve the birefringence and heat resistance.

[0105] The liquid crystal polymer film of the present invention is a liquid crystal polymer film having a structure represented by the formula (9), in which Q is -CH=N-, and R 11 In the case of a side-chain liquid crystal polymer where Q is an amino group, and Q is -N=CH-, and R 11 In the case of a side-chain liquid crystal polymer in which R is an aldehyde group, when the condensation compound is introduced, R 11 The amino group or aldehyde group in the side chain may undergo a condensation reaction with the side chain residue to form a crosslinked structure, and such a side chain type liquid crystal polymer is preferred because it can improve heat resistance.

[0106] For example, the liquid crystal polymer film of the present invention may contain a side chain liquid crystal polymer having a side chain structure represented by the following formula (10) (hereinafter, sometimes referred to as side chain structure (10)). <Side chain structure (10)> [ka] In the formula, a is 0 or 1; f is an integer of 0 to 3; p is an integer of 0 to 12; q is 0 or 1; X is a single bond, -COO-, -OCO-, or -C≡C-; Z4 is a single bond, -O-, -COO-, -OCO-, -N=N-, -NO=N-, -CH=CH-, -C≡C-, -CO-CH=CH-, -CH=CH-CO-, -CH=N-, or -N=CH-; a hydrogen atom, an alkyl group (e.g., C 1-6 Alkyl groups, preferably C 1-4 alkyl groups), alkyloxy groups (e.g., C 1-6 Alkyloxy groups, preferably C 1-4 alkyloxy group), halogen atom, cyano group, or carboxy group; R2, R3, R 19 and R 20 are the same or different and may be hydrogen atoms, alkyl groups (e.g., C 1-6 Alkyl groups, preferably C 1-4 alkyl groups), alkyloxy groups (e.g., C 1-6 Alkyloxy groups, preferably C 1-4 alkyloxy group), halogen atom, or cyano group. 19 and R 20 Each represents a substituent at a substitutable position on the benzene ring, and these positions may be the same or different. When f is 2 or 3, multiple chemical structures in parentheses are bonded, and their Z4 and R 20 may be the same or different.

[0107] The side chain structure (10) is a chemical structure that is difficult to photo-align, and therefore it is difficult to prepare an optically anisotropic liquid crystal polymer film using a side chain liquid crystal polymer having such a side chain structure as a raw material. However, the production method of the present invention makes it possible to prepare a liquid crystal polymer film that contains a side chain liquid crystal polymer having such a side chain structure and has excellent in-plane dichroism.

[0108] The side chain structure (10) has a salicylideneaniline skeleton. As described above, salicylideneaniline derivatives undergo phototautomerization due to intramolecular hydrogen migration when irradiated with ultraviolet light, as shown in Reaction Scheme 3, and can emit polarized light.

[0109] The side chain structures (8) to (10) represent the chemical structures at the ends of the side chains in the repeating units, and various chemical structures may be included between these side chain structures and the main chain structure as long as the effects of the present invention are not impaired.

[0110] The side-chain liquid crystal polymer constituting the liquid crystal polymer film of the present invention may be a homopolymer consisting of the same repeating unit containing any one of the side-chain structures (8) to (10), or may be a copolymer containing, in addition to the side-chain structures (8) to (10), a repeating unit containing a side-chain residue that has not reacted in the condensation reaction step or a crosslinked side chain, or a repeating unit containing a side-chain structure different from these side chains.

[0111] When the side-chain liquid crystal polymer constituting the liquid crystal polymer film of the present invention is a copolymer, it may have a side chain having a mesogen component in addition to the side chain structures (8) to (10). For example, it may have a side chain having the side chain structure represented by the above formula (2).

[0112] The liquid crystal polymer film of the present invention may further contain a compound other than the side-chain liquid crystal polymer. Such a compound may be a high molecular weight compound or a low molecular weight compound. For example, in order to adjust the optical properties of the liquid crystal polymer film, a polymer having a side chain having the side chain structure (2) may be contained. In particular, when R5 in the above formula (2) is a carboxy group, it not only acts as a catalyst for the hydrolysis reaction of the side chain of the side-chain liquid crystal polymer, but also can form a mesogenic structure by forming hydrogen bonds and dimerizing, thereby exhibiting liquid crystallinity.

[0113] The side-chain liquid crystal polymer constituting the liquid crystal polymer film of the present invention may have a main chain structure having a linear or cyclic skeletal chain such as a polyacrylate, polymethacrylate, polyvinyl, polysiloxane, polyether, or polymaleimide.

[0114] The liquid crystal polymer film of the present invention is a liquid crystal polymer film produced by the above-mentioned production method, and may be a liquid crystal polymer film having optical anisotropy. The liquid crystal polymer film of the present invention can be used as a member of an optically anisotropic element.

[0115] The optically anisotropic element of the present invention may comprise a transparent substrate and the liquid crystal polymer film formed on the transparent substrate. Due to the improved optical properties of the optically anisotropic element of the present invention, it can be used as a retardation film, a liquid crystal alignment film, a pattern retarder, a polarized diffraction grating, a radial polarization converter, etc., used in optical devices and display devices. In addition, if it has polarized light emission, it can be used as a polarized light-emitting film, and can be used for backlights, etc. [Example]

[0116] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. In the following examples and comparative examples, various physical properties were measured by the following methods.

[0117] In the following examples and comparative examples, various physical properties were measured by the following methods. The molecular weight was measured using a GPC apparatus (JASCO Corporation, PU-2080, RI-2031) equipped with a Shodex column manufactured by Showa Denko K.K. as the column and tetrahydrofuran (THF) as the eluent, and calculated in terms of polystyrene. The phase transition temperature was measured using a differential scanning calorimeter (Seiko Instruments Inc., SSC5200H). The dichroic ratio was measured using a spectrophotometer (U-3010, Hitachi High-Tech Science Corporation) equipped with a Glan-Taylor polarizing prism and calculated from the polarized absorption spectrum. The dichroic ratio D shown in Table 1 indicates the dichroic ratio at the absorption wavelength showing the highest value D. The birefringence was measured at a wavelength of 633 nm by the Senarmont method using a polarizing microscope (Olympus Corporation, BX51) equipped with a heating / cooling device (LINKAM Corporation, TH600PM). The emission spectrum was measured by photoluminescence (PL) measurement using a spectrofluorometer (F-7000, manufactured by Hitachi High-Tech Science Corporation), and the wavelength showing the maximum emission intensity was calculated as PLmax.

[0118] (Monomer 1) 4-(6-hydroxyhexyloxy)benzoic acid was synthesized by heating 4-hydroxybenzoic acid and 6-chloro-1-hexanol under alkaline conditions. This product was then esterified with a large excess of methacrylic acid in the presence of p-toluenesulfonic acid to synthesize Monomer 1 shown in Chemical Formula 1. [ka]

[0119] (Monomer 2) 4-(6-hydroxyhexyloxy)benzaldehyde was synthesized by heating 4-hydroxybenzaldehyde and 6-chloro-1-hexanol under alkaline conditions. This product was esterified with a large excess of methacrylic acid in the presence of p-toluenesulfonic acid to synthesize Monomer 2 shown in Chemical Formula 2. [ka]

[0120] (Monomer 3) Monomer 1 was reacted with thionyl chloride to synthesize an acid chloride, and then this product was reacted with 4-hydroxybenzaldehyde in the presence of triethylamine to synthesize the compound shown in Chemical Formula 3. [ka]

[0121] Next, this product was subjected to dehydration condensation with p-anisidine to synthesize monomer 3 represented by chemical formula 4. [ka]

[0122] (Monomer 4) 4-(6-hydroxyhexyloxy)aniline was synthesized by heating 4-aminophenol and 6-chloro-1-hexanol under alkaline conditions. This product was then subjected to an esterification reaction with a large excess of methacrylic acid in the presence of p-toluenesulfonic acid to synthesize 4-(6-methacryloyloxyhexyloxy)aniline. Monomer 4, shown in chemical formula 5, was then synthesized by dehydration condensation with 4-methoxybenzaldehyde.

[0123] [ka]

[0124] (Monomer 5) 4-(6-hydroxyhexyloxy)aniline was synthesized by heating 4-aminophenol and 6-chloro-1-hexanol under alkaline conditions. This product was then subjected to an esterification reaction with a large excess of methacrylic acid in the presence of p-toluenesulfonic acid to synthesize 4-(6-methacryloyloxyhexyloxy)aniline. Monomer 5, shown in chemical formula 6, was then synthesized by dehydration condensation with 4-methoxysalicylaldehyde. [ka]

[0125] (Copolymer 1)P1 Monomer 1 and monomer 2 were dissolved in THF so that the molar ratio of monomer 1 to monomer 2 was 80:20, and azobisisobutyronitrile (AIBN) was added as a reaction initiator to polymerize the monomers to obtain copolymer 1. The number-average molecular weight of copolymer 1 was 38,000 and the weight-average molecular weight was 87,400. This copolymer 1 exhibited liquid crystallinity in the temperature range from 50°C to 132°C.

[0126] (Polymer 2) P2 Monomer 3 was dissolved in THF, and polymerization was carried out with the addition of AIBN as a reaction initiator to obtain polymer 2. This polymer 2 exhibited liquid crystallinity in the temperature range from 120°C to 295°C.

[0127] (Copolymer 3)P3 Monomer 1 and monomer 4 were dissolved in THF at a molar ratio of 80:20, and AIBN was added as a reaction initiator to polymerize them to obtain copolymer 3. This copolymer 3 exhibited liquid crystallinity in the temperature range of 115°C to 151°C.

[0128] (Polymer 4) P4 Monomer 5 was dissolved in THF, and polymerized by adding AIBN as a reaction initiator to obtain polymer 4.

[0129] (Compound 1) As Compound 1, commercially available p-anisidine (manufactured by Tokyo Chemical Industry Co., Ltd.) was purified by recrystallization from ethanol and used.

[0130] (Compound 2)SB As Compound 2, commercially available 4-aminostilbene (hereinafter sometimes referred to as SB; manufactured by Tokyo Chemical Industry Co., Ltd.) was purified by recrystallization from ethanol and used.

[0131] (Compound 3) MSB As Compound 3, commercially available 4-amino-4'-methoxystilbene (hereinafter sometimes referred to as MSB; manufactured by Tokyo Chemical Industry Co., Ltd.) was purified by recrystallization from ethanol and used.

[0132] (Compound 4)FL As Compound 4, commercially available 2,7-diaminofluorene (hereinafter sometimes referred to as FL; manufactured by Tokyo Chemical Industry Co., Ltd.) was purified by recrystallization from ethanol and used.

[0133] (Compound 5)TD As Compound 5, commercially available m-tolidine (hereinafter sometimes referred to as TD; manufactured by Tokyo Chemical Industry Co., Ltd.) was purified by recrystallization from ethanol and used.

[0134] (Compound 6) As Compound 6, commercially available 2-aminofluorene (manufactured by Tokyo Chemical Industry Co., Ltd.) was purified by recrystallization from ethanol and used.

[0135] (Compound 7) As Compound 7, commercially available 2-hydroxy-4-methoxybenzaldehyde (manufactured by Tokyo Chemical Industry Co., Ltd.) was purified by recrystallization from ethanol and used.

[0136] (Compound 8) As Compound 8, commercially available 4-formyl-3-hydroxybenzoic acid (manufactured by Sigma-Aldrich) was purified by recrystallization from ethanol and used.

[0137] Example 1 A solution was prepared by dissolving the materials for copolymer 1 and compound 1 in THF at a molar ratio of copolymer 1:compound 1 = 1:2. This solution was applied to a quartz substrate using a spin coater to a thickness of approximately 0.2 μm. After drying at room temperature, the substrate was heated at 100°C for 10 minutes to cause dehydration condensation between copolymer 1 and compound 1, forming a polymer film made of a photosensitive liquid crystal polymer. Three of these polymer films were prepared, and then ultraviolet light from an ultra-high pressure mercury lamp was passed through a 365 nm bandpass filter and a polarizer to become linearly polarized ultraviolet light, resulting in a photoirradiation of 2 J / cm. 2 , 5J / cm 2 , 20J / cm 2 were irradiated, respectively.

[0138] The change in the polarized UV-vis absorption spectrum of this polymer film is shown in Figure 1. The dichroic ratio (D) is defined by the following formula: D=(A⊥-A||) / (A⊥+A||) (In the formula, A⊥ represents the absorbance when the electric field vectors of the irradiated polarized UV light and the detected light during polarized UV-vis spectrum measurement are perpendicular, and A|| represents the absorbance when the electric field vectors of the irradiated polarized UV light and the detected light during polarized UV-vis spectrum measurement are perpendicular.)

[0139] As shown in Figure 1, the dichroic ratio (D 262 ) hardly occurs, and the dichroic ratio (D 335 ) was generated, it can be seen that the benzylideneaniline group is undergoing an axially selective photoreaction. 335 was less than 0.01.

[0140] After that, polarized UV light was applied at 5 J / cm 2 The polymer film was then heat-treated at 140°C for 10 minutes in a nitrogen atmosphere. The change in the polarized UV-vis absorption spectrum of the resulting polymer film is shown in Figure 2. As can be seen from Figure 2, cooperative reorientation occurred, resulting in a D peak at 262 nm, which is attributable to the benzoic acid group. 262= 0.74, D at 335 nm absorption due to benzylideneaniline group 335 A polymer film with a large dichroic ratio of 0.69 was fabricated. The retardation value and thickness of this polymer film were measured, and the birefringence Δn was calculated to be 0.12.

[0141] Next, the polymer film in which cooperative reorientation had occurred was heat-treated at 125°C for 80 minutes in an air atmosphere with a humidity of 35%. The change in the polarized UV-vis absorption spectrum of the resulting polymer film is shown in Figure 3. From Figure 3, it can be seen that the absorption at 262 nm and the dichroic ratio derived from the benzoic acid group were maintained, while the absorption at 335 nm derived from the benzylideneaniline group decreased, indicating that the orientation of the benzoic acid group was maintained while the photosensitive group, the benzylideneaniline group, was hydrolyzed. The D of this polymer film 262 =0.63 and Δn was 0.08.

[0142] Next, a solution of compound 2 was prepared by dissolving it in diethyl ether. This solution was applied to the hydrolyzed polymer film using a spin coater and then heat-treated at 130°C for 10 minutes under a nitrogen atmosphere. The change in the polarized UV-vis absorption spectrum of the resulting liquid crystal polymer film is shown in Figure 4. As shown in Figure 4, a new peak was observed at 355 nm, and the dichroic ratio of this absorption was D 355 = 0.78, which is a large value. This indicates that the benzaldehyde group in the side chain residue after hydrolysis and compound 2 undergo a dehydration condensation reaction to generate benzylideneaniline groups, which are then oriented. The Δn of the resulting liquid crystal polymer film was 0.13.

[0143] Figure 5 (P1 / SB) shows the change in Δn when this liquid crystal polymer film was heated under a nitrogen atmosphere. The maximum temperature at which Δn did not change was defined as the heat resistance temperature (TS). Figure 5 (P1 / SB) shows that there was no change in Δn up to 155°C, and the TS of the obtained liquid crystal polymer film was 155°C.

[0144] Example 2 A liquid crystal polymer film shown in Table 1 was obtained in the same manner as in Example 1, except that Compound 3 was used instead of Compound 2. The obtained liquid crystal polymer film had a D 262 = 0.75, and D in the absorption at 366 nm from the benzylideneaniline group 366 =0.82 and Δn was 0.14. From Fig. 5 (P1 / MSB), the TS of the obtained liquid crystal polymer film was 150°C.

[0145] Example 3 A liquid crystal polymer film shown in Table 1 was obtained in the same manner as in Example 1, except that Compound 4 was used instead of Compound 2. The obtained liquid crystal polymer film had a D 262 = 0.68, and D in the absorption at 378 nm from the benzylideneaniline group 378 =0.71 and Δn was 0.18. From Fig. 5 (P1 / FL), the TS of the obtained liquid crystal polymer film was 180°C.

[0146] Example 4 A liquid crystal polymer film shown in Table 1 was obtained in the same manner as in Example 1, except that Compound 5 was used instead of Compound 2. The obtained liquid crystal polymer film had a D 262 = 0.63, and D in the absorption at 341 nm from the benzylideneaniline group 341 =0.62 and Δn was 0.14. From Fig. 5 (P1 / TD), the TS of the obtained liquid crystal polymer film was 165°C.

[0147] Example 5 A solution of polymer 2 was prepared by dissolving it in THF. This solution was applied to a quartz substrate using a spin coater to a thickness of approximately 0.2 μm. After drying the substrate at room temperature, ultraviolet light from an ultra-high pressure mercury lamp was passed through a 365 nm bandpass filter and a polarizer to become linearly polarized ultraviolet light, and then the substrate was exposed to 7 J / cm 2 After the irradiation, the polymer film was heat-treated at 200°C for 10 minutes in a nitrogen atmosphere. The dichroic ratio D 266= 0.8, and the dichroic ratio D 335 =0.82 and Δn was 0.24.

[0148] The oriented polymer film was then immersed in a dilute aqueous acetic acid solution (pH = 3.0) for 60 minutes to hydrolyze the Schiff base, and then washed with methanol and diethyl ether. The Δn of the resulting polymer film was 0.08.

[0149] Next, a solution (4 wt%) of Compound 6 was prepared by dissolving it in ethylene glycol. This solution was applied to the washed polymer film using a spin coater and then heat-treated at 50°C for 60 minutes under a nitrogen atmosphere. The obtained liquid crystal polymer film had a dichroic ratio D 350 =0.79, Δn was 0.40, and TS was 315°C.

[0150] Example 6 A solution of copolymer 3 in THF was prepared. This solution was applied to a quartz substrate using a spin coater to a thickness of approximately 0.2 μm. After drying the substrate at room temperature, ultraviolet light from an ultra-high pressure mercury lamp was passed through a 365 nm bandpass filter and a polarizer to become linearly polarized ultraviolet light, and the substrate was then exposed to a 7 J / cm 2 After the irradiation, the polymer film was heat-treated at 145°C for 10 minutes in a nitrogen atmosphere. The dichroic ratio D 266 = 0.64, and the dichroic ratio D 335 =0.59.

[0151] Next, the oriented polymer film was heat-treated at 110°C for 60 minutes in an air atmosphere with a humidity of 35% to hydrolyze the Schiff base. The obtained polymer film exhibited a dichroic ratio D 264 =0.66.

[0152] Next, a solution of compound 7 was prepared in diethyl ether. This solution was applied to the hydrolyzed polymer film using a spin coater and then heat-treated at 100°C for 10 minutes under a nitrogen atmosphere. The resulting liquid crystal polymer film had a dichroic ratio D = 0.70 in the absorption due to the benzylidene aniline group. Furthermore, when the resulting liquid crystal polymer film was irradiated with UV light and placed under a polarizer, polarized light emission of yellow-green (PLmax = 508 nm) was confirmed.

[0153] Example 7 A liquid crystal polymer film shown in Table 1 was obtained in the same manner as in Example 6, except that compound 8 was used instead of compound 7. The obtained liquid crystal polymer film had a dichroic ratio D of 0.63 in the absorption derived from the benzylideneaniline group. Furthermore, when the obtained liquid crystal polymer film was irradiated with UV light and placed under a polarizing plate, yellow polarized light emission (PLmax = 546 nm) was confirmed.

[0154] (Comparative Example 1) A solution was prepared by dissolving the materials for copolymer 1 and compound 1 in THF at a molar ratio of copolymer 1:compound 1 = 1:2. This solution was applied to a quartz substrate using a spin coater to a thickness of approximately 0.2 μm. After drying the substrate at room temperature, it was heated at 100°C for 10 minutes to cause dehydration condensation between copolymer 1 and compound 1, thereby forming a polymer film made of a photosensitive liquid crystal polymer. Next, ultraviolet light from an ultra-high pressure mercury lamp was passed through a 365 nm bandpass filter and a polarizer to become linearly polarized ultraviolet light, and this polymer film was irradiated with 5 J / cm. 2 After the irradiation, the polymer film was heat-treated in a nitrogen atmosphere at 130°C for 10 minutes and then at 125°C for 100 minutes. The obtained polymer film had a dichroic ratio D 335 =0.69, Δn was 0.12, and TS was 146°C.

[0155] (Comparative Example 2) The oriented polymer film obtained in Comparative Example 1 was heat-treated at 125°C for 80 minutes in an air atmosphere with a humidity of 35% to hydrolyze the Schiff base. The obtained polymer film had a dichroic ratio D262 =0.63, Δn was 0.08, and TS was 130°C.

[0156] (Comparative Example 3) Polymer 4 was dissolved in THF to prepare a solution. This solution was applied to a quartz substrate using a spin coater to a thickness of approximately 0.2 μm. Ultraviolet light from an ultra-high pressure mercury lamp was passed through a 365 nm bandpass filter and a polarizer to become linearly polarized ultraviolet light, and the applied voltage was 1 to 20 J / cm. 2 After irradiation, heat treatment was carried out at 80 to 140°C, but no orientation was observed in the resulting polymer film.

[0157] [Table 1]

[0158] In Examples 1 to 4, a polymer film made of a side-chain liquid crystal polymer, which is the raw material for the film, was prepared by condensation reaction of Copolymer 1 with Compound 1 as a precursor polymer compound, and orientation was induced by light irradiation and heating, followed by hydrolysis reaction. Various amine compounds were then applied and condensation reaction was carried out to obtain a liquid crystal polymer film. Comparative Example 1 corresponds to the polymer film before the hydrolysis reaction, and Comparative Example 2 corresponds to the polymer film after the hydrolysis reaction and before the condensation reaction. However, the liquid crystal polymer films obtained in Examples 1 to 4 exhibited higher values ​​of birefringence Δn and heat resistance temperature TS than Comparative Examples 1 and 2, and had improved physical properties compared to the polymer films made from the raw materials.

[0159] In Example 5, a polymer film was prepared using polymer 2, and orientation was induced by light irradiation and heating. The film was then subjected to a hydrolysis reaction, and an amine compound was applied and subjected to a condensation reaction to obtain a liquid crystal polymer film. The birefringence index Δn of the liquid crystal polymer film obtained in Example 5 was 0.40, which is improved from the birefringence index Δn of the polymer film before the hydrolysis reaction, which was 0.24. Furthermore, the heat resistance temperature TS of the liquid crystal polymer film obtained in Example 5 was 315°C, demonstrating high heat resistance.

[0160] In Examples 6 and 7, a polymer film was prepared using copolymer 3, and orientation was induced by light irradiation and heating. After this, a hydrolysis reaction was carried out, and various aldehyde compounds were then applied and subjected to a condensation reaction to obtain a liquid crystal polymer film. The liquid crystal polymer films obtained in Examples 6 and 7 exhibited polarized luminescence due to the formation of a salicylideneaniline derivative in the side chain of the side-chain liquid crystal polymer, and the color of the emitted light could be adjusted by the influence of the substituents substituted on the salicylideneaniline. In Comparative Example 3, a film was prepared using the polymer having the salicylideneaniline derivative in the side chain formed in Example 6 as a raw material, but molecular orientation was not achieved. [Industrial Applicability]

[0161] As described above, the present invention can produce a liquid crystal polymer film with improved physical properties or a liquid crystal polymer film having predetermined characteristics. The liquid crystal polymer film of the present invention can be formed on a transparent substrate and used as an optically anisotropic element, a retardation film, an optical compensation film, a polarized light-emitting film, etc. Furthermore, by utilizing the orientation of the liquid crystal polymer, it can also be used as a liquid crystal alignment film. It can also be used as a liquid crystal display element comprising a pair of liquid crystal alignment films and a liquid crystal layer disposed between a pair of optical elements.

[0162] As described above, the preferred embodiment of the present invention has been described, but various additions, modifications, or deletions can be made without departing from the spirit of the present invention, and such additions, modifications, or deletions are also included within the scope of the present invention.

Claims

1. a film-forming step of forming a polymer film containing a side-chain liquid crystal polymer having a mesogen component, a side chain having a hydrolyzable group, and a side chain having a photosensitive group, or a side chain having a mesogen component, a hydrolyzable group, and a photosensitive group, wherein the mesogen component, the hydrolyzable group, and the photosensitive group may exist independently or may exist in a composite form sharing a chemical structure; a light irradiation step of irradiating the obtained polymer film with light capable of causing a photoreaction of the photosensitive groups and anisotropically orienting the mesogen components; a thermal orientation step of heating the light-irradiated polymer film to induce orientation of the unoriented mesogen components; a hydrolysis step of heating the polymer film at a temperature lower than its isotropic phase transition temperature to hydrolyze the hydrolyzable groups and generate side chain residues together with the elimination compound; a coating step of coating a condensable compound having a condensable group capable of undergoing a condensation reaction with a side chain residue onto the polymer film in which the mesogen component is oriented; a condensation reaction step in which a condensation reaction is carried out between the side chain residue and a condensable compound; A method for producing a liquid crystal polymer film, comprising at least the steps of:

2. The method for producing a liquid crystal polymer film according to claim 1, wherein the condensable group of the side chain residue is an aldehyde group or an amino group, and the condensable compound is at least one compound selected from the group consisting of compounds represented by the following formulas (5) to (7): 【Chemistry 1】 (wherein c is an integer of 0 to 3; Z １ is a single bond, —O—, —COO—, —OCO—, —N═N—, —CH═CH—, —C≡C—, —CO—CH═CH—, —CH═CH—CO—, —CH═N—, or —N═CH—; Q ３ Ha-NH ２ or -CHO; R ８ is a hydrogen atom, an alkyl group, an alkyloxy group, a halogen atom, a cyano group, an amino group, an aldehyde group, a carboxy group, or a cinnamic acid group; R ９ and R １０ are the same or different and are a hydrogen atom, an alkyl group, an alkyloxy group, a halogen atom, or a cyano group. 【Chemistry 2】 (wherein d and e are the same or different and are integers of 0 to 2; Z ２ and Z ３ are the same or different and each represents a single bond, —O—, —COO—, —OCO—, —N═N—, —CH═CH—, —C≡C—, —CO—CH═CH—, —CH═CH—CO—, —CH═N—, or —N═CH—; Q ４ Ha-NH ２ or -CHO; R １１ is a hydrogen atom, an alkyl group, an alkyloxy group, a halogen atom, a cyano group, an amino group, or an aldehyde group; R １２ , R １３ , R １４ , R １５ , R １６ , and R １７ are the same or different and are a hydrogen atom, an alkyl group, an alkyloxy group, a halogen atom, or a cyano group. 【Transformation 3】 (wherein f is an integer of 0 to 3; Z ４ is a single bond, —O—, —COO—, —OCO—, —N═N—, —CH═CH—, —C≡C—, —CO—CH═CH—, —CH═CH—CO—, —CH═N—, or —N═CH—; R １８ is a hydrogen atom, an alkyl group, an alkyloxy group, a halogen atom, a cyano group, or a carboxy group; R １９ and R ２０ are the same or different and are a hydrogen atom, an alkyl group, an alkyloxy group, a halogen atom, or a cyano group.

3. 3. The method for producing a liquid crystal polymer film according to claim 1, wherein the side chain of the side chain liquid crystal polymer has a side chain structure represented by the following formula (1): 【Chemistry 4】 (wherein a is 0 or 1; p is an integer of 0 to 12; q is 0 or 1; X is a single bond, —COO—, —OCO—, or —C≡C—; Q is —CH═N— or —N═CH—; R １ , R ２ , R ３ and R ４ are the same or different and are a hydrogen atom, an alkyl group, an alkyloxy group, a halogen atom, or a cyano group.

4. The method for producing a liquid crystal polymer film according to any one of claims 1 to 3, wherein in the polymer film obtained in the film formation step, the side chain-type liquid crystal polymer further has a side chain having a functional group that has a catalytic activity for a hydrolysis reaction, in addition to the side chain having a mesogen component and a hydrolyzable group or the side chain having a mesogen component, a hydrolyzable group, and a photosensitive group, and the side chain is a copolymer having a side chain structure represented by the following formula (2), and / or further contains a polymer having a side chain having a side chain structure represented by the following formula (2): 【Transformation 5】 (wherein b is 0 or 1; r is an integer from 0 to 12; s is 0 or 1; Y is a single bond, —COO—, —OCO—, or —C≡C—; R ５ is a carboxy group or a sulfo group; R ６ and R ７ are the same or different and are a hydrogen atom, an alkyl group, an alkyloxy group, a halogen atom, or a cyano group.

5. A liquid crystal polymer film comprising a side-chain liquid crystal polymer having a side-chain structure represented by the following formula (9), wherein the liquid crystal polymer film has a dichroic ratio D of 0.5 or more: 【Transformation 6】 (wherein a is 0 or 1; d and e are the same or different and are an integer of 0 to 2; p is an integer of 0 to 12; q is 0 or 1; X is a single bond, —COO—, —OCO—, or —C≡C—; Q is —CH═N— or —N═CH—; Z ２ and Z ３ are the same or different and each represents a single bond, —O—, —COO—, —OCO—, —N═N—, —CH═CH—, —C≡C—, —CO—CH═CH—, —CH═CH—CO—, —CH═N—, or —N═CH—; R １１ is a hydrogen atom, an alkyl group, an alkyloxy group, a halogen atom, a cyano group, or an amino group; R ２ , R ３ , R １２ , R １３ , R １４ , R １５ , R １６ , and R １７ are the same or different and are a hydrogen atom, an alkyl group, an alkyloxy group, a halogen atom, or a cyano group.

6. A liquid crystal polymer film comprising a side-chain liquid crystal polymer having a side-chain structure represented by the following formula (10), wherein the liquid crystal polymer film has a dichroic ratio D of 0.5 or more: 【Transformation 7】 (wherein a is 0 or 1; f is an integer of 0 to 3; p is an integer of 0 to 12; q is 0 or 1; X is a single bond, —COO—, —OCO—, or —C≡C—; Z ４ is a single bond, —O—, —COO—, —OCO—, —N═N—, —CH═CH—, —C≡C—, —CO—CH═CH—, —CH═CH—CO—, —CH═N—, or —N═CH—; R １８ is a hydrogen atom, an alkyl group, an alkyloxy group, a halogen atom, a cyano group, or a carboxy group; R ２ , R ３ , R １９ and R ２０ are the same or different and are a hydrogen atom, an alkyl group, an alkyloxy group, a halogen atom, or a cyano group.

7. 7. An optically anisotropic element comprising the liquid crystal polymer film according to claim 5.

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