JP6518934B2 - Method for producing liquid crystal polymer film - Google Patents

Description

  The present invention relates to a liquid crystal polymer film that can be used for an optically anisotropic element, a liquid crystal alignment film, and a method for producing a liquid crystal polymer film.

  In Patent Document 1 (Japanese Patent Application Laid-Open No. 11-181127), the present inventors irradiate an ultraviolet ray having linear polarization to a photosensitive side chain type polymer film to obtain an alignment film having an arbitrary alignment characteristic. In a method for producing an alignment film characterized by the above, in Patent Document 2 (Japanese Patent Application Laid-Open No. 2002-90750), a liquid crystal panel is irradiated with light of linear polarization or partial polarization on a photosensitive polymer film. A film has been proposed which promotes the alignment of the enclosed liquid crystal.

  Further, in Patent Document 3 (Japanese Patent Application Laid-Open No. 2002-202409), a film of a mixture of a photosensitive polymer and a low molecular weight compound is molecularly oriented by irradiating light with light, and the phase difference and light in the polymer material are obtained. In a retardation film in which an axial direction is optionally expressed, in Patent Document 4 (Japanese Patent Application Laid-Open No. 2003-307618), a film is formed with a photosensitive material, and light irradiation from a direction inclined to the film surface, or In addition, a retardation film has been proposed which is characterized in that it is manufactured by a process including an operation of heating and cooling.

  In these materials, when applied to a substrate to form a film, irradiation with linearly polarized ultraviolet light causes an axially selective photocrosslinking reaction of polymer side chains. Furthermore, when such a film is heated, the side chains which have not reacted by the irradiation of linearly polarized ultraviolet light can be oriented along the side chains which are photoselectively cross-linked, by the liquid crystallinity of the material itself. . As a result, the entire film can also be molecularly oriented. This film can be used as a liquid crystal alignment film because it exhibits the alignment ability of liquid crystal molecules. Furthermore, since birefringence is exhibited by molecular orientation, it can be used as a retardation film.

JP 11-181127 A Japanese Patent Application Laid-Open No. 2002-90750 Japanese Patent Laid-Open No. 2002-202409 Unexamined-Japanese-Patent No. 2003-307618

  However, since the materials described in Patent Documents 1 to 4 are liquid crystalline polymer materials which are solid in a normal state, they need to be formed into a film or film to be used as an alignment film, retardation film, etc. is there.

  In order to form such a solid liquid crystalline polymer material in the form of a film or a film, it is necessary to dissolve the material in a solvent and apply and dry it on a substrate to form a film. However, the materials proposed so far tend to have low solubility in common organic solvents. On the other hand, a solvent having good solubility in a solid liquid crystalline polymer material may damage the substrate when applying the material, or may be a solvent with high environmental load such as a halogen-containing solvent.

  Therefore, when the solubility of the solid liquid crystalline polymer material in a general organic solvent is low, the types of usable solvents are limited, and even if the material is excellent, it is difficult to process it into a film or a film. May be

  In view of the above problems, in the present invention, in the case of forming a liquid crystal polymer film having optical anisotropy and / or liquid crystal alignment ability, the selection range of the film forming solvent is broadened or dissolved in the solvent. The present invention proposes a material system and a manufacturing method capable of forming a film or a film, and solves the above-mentioned problems in the prior art.

  MEANS TO SOLVE THE PROBLEM As a result of earnestly researching in order to solve the said subject, this inventor discovered the following invention.

That is, according to the first configuration of the present invention, a solution containing at least two compounds capable of forming a liquid crystal polymer having a photosensitive functional group (hereinafter referred to as a photosensitive liquid crystal polymer) is produced by a condensation reaction. A film forming step of forming a film or separately forming a solution of each compound;
A condensation reaction step of subjecting the compound to a condensation reaction to form a photosensitive liquid crystal polymer in the film obtained in the film forming step;
Irradiating the obtained photosensitive liquid crystal polymer with light capable of anisotropically orienting the mesogen portion in the photosensitive liquid crystal polymer;
A liquid crystal polymer film.

  The manufacturing method may further include a heating step of heating the light irradiation film from the viewpoint of improving the alignment of the liquid crystal polymer.

  For example, in this production method, a functional group having photosensitivity may be formed by condensation reaction of an aromatic amine compound and an aromatic aldehyde compound.

  The liquid crystal polymer may be a side chain type liquid crystal polymer, and a functional group having photosensitivity represented by the following chemical formula 1 may be formed on the side chain.

(Wherein, R is a hydrogen atom, a halogen group, -CN, an alkyl group or an alkyloxy group)

  In the production method, the solvent for preparing the solution is preferably a non-halogen solvent.

  A second structure of the present invention is a liquid crystal polymer film produced by any of the above-mentioned production methods, which has optical anisotropy, has liquid crystal alignment ability, or has liquid crystal alignment ability and optical ability Liquid crystal polymer film having a specific anisotropy. In this liquid crystal polymer film, the liquid crystal polymer may be a side chain type liquid crystal polymer, and the side chain may have a structure represented by the above formula 1.

  A third configuration of the present invention is an optically anisotropic element comprising a transparent substrate and a liquid crystal polymer film formed on the transparent substrate, wherein the liquid crystal polymer film is described above. It may be an optically anisotropic element which is a thin film.

  The fourth configuration of the present invention is a liquid crystal alignment film comprising a transparent substrate and a liquid crystal polymer film formed on the transparent substrate, wherein the liquid crystal polymer film is the film described above. It may be a liquid crystal alignment film.

  A fifth configuration of the present invention is a liquid crystal display element comprising a pair of alignment films and a liquid crystal layer disposed between the pair of optical elements, wherein the alignment film is the film described above. Or a liquid crystal display device.

  In the present invention, since a photosensitive liquid crystal polymer is produced by condensation reaction of a material system after forming a film of a specific material system, it becomes possible to expand the selection range of the film forming solvent to a general solvent. Furthermore, a liquid crystal alignment film to which liquid crystal alignment ability is imparted or a liquid crystal polymer film having optical anisotropy can be efficiently produced by irradiating the photosensitive liquid crystal polymer obtained by the condensation reaction with light.

  Furthermore, such a liquid crystal polymer film can be usefully used as an optically anisotropic element or a liquid crystal alignment film. Furthermore, when it combines with a liquid crystal layer as a liquid crystal aligning film, a liquid crystal display element can be obtained.

5 is a graph showing a polarized UV-vis absorption spectrum of the polymer film after polarized light irradiation obtained in Example 1. FIG. In Example 2, the UV-vis absorption spectrum of the coating film (B) after heat treatment after applying p-anisidine to the coating film (A) which applied and dried the polymer 1 after coating and further to the coating film (A) is shown. It is a graph. In Example 2, it is a graph which shows the infrared absorption spectrum of a coating film (A) and a coating film (B). In Example 2, after irradiation with polarized light, it is a graph showing a polarized UV-vis absorption spectrum of a film after heat treatment at 130 ° C. for 10 minutes. Graph showing a UV-vis absorption spectrum of a coated film after heat treatment of a solution in which polymer 1 and p-anisidine are dissolved in acetone at a mixing ratio of 1: 0.5 to 1: 5 in Example 3 in a mixing ratio It is. In Example 3, the injection amount was changed to 0.01 to 500 J / cm ² for a solution in which polymer 1 and p-anisidine were dissolved in acetone at a mixing ratio of molar ratio 1: 0.5 to 1: 5. It is a graph which shows the orientation degree change of the film which has each mixing ratio at the time of irradiating.

According to a first aspect of the present invention, there is provided a method of producing a liquid crystal polymer film, the method comprising
A solution containing at least two compounds capable of forming a liquid crystal polymer having a photosensitive functional group (hereinafter referred to as a photosensitive liquid crystal polymer) is formed into a film by condensation reaction, or a solution of each compound is overlapped. Forming a film separately so as to have a region;
A condensation reaction step of subjecting the compound to a condensation reaction to form a photosensitive liquid crystal polymer in the obtained film;
At least the step of irradiating the obtained photosensitive liquid crystal polymer with light capable of anisotropically orienting the mesogen portion in the liquid crystal polymer to orient the mesogen portion in the liquid crystal polymer.

(Film forming process)
In the film forming step, film formation is performed using a solution containing at least two types of compounds capable of forming a photosensitive liquid crystal polymer by condensation reaction, or individual solutions of these compounds.
In addition, a condensation reaction is a chemical reaction which reacts between functional groups of at least 2 types of compounds here, and involves elimination of molecules such as water, alcohols, ammonia, amines, hydrogen halide and the like.

[Compound capable of forming a photosensitive liquid crystal polymer by condensation reaction]
At least two types of compounds capable of forming a photosensitive liquid crystal polymer by a condensation reaction have condensable groups capable of condensation reaction with each other.
Examples of the condensable group include a hydroxyl group, an aldehyde group, a ketone group, an amino group, a nitro group, a nitroso group, a carboxyl group and the like, and these condensable groups are combined according to known or common knowledge to perform condensation reaction. It can be used for

  The photosensitive liquid crystal polymer is a polymer having a photosensitive group and a mesogen component which is a rigid portion exhibiting liquid crystallinity. In the photosensitive liquid crystal polymer, the photosensitive group and the mesogenic component may be independently present, or the photosensitive group may be part of the mesogenic component.

  The mesogen component may form a main chain of the liquid crystal polymer, but from the viewpoint of improving the solubility in the solvent, the liquid crystal polymer includes a mesogenic component in a side chain, a side chain type liquid crystal polymer Is preferred.

  The side chain type liquid crystal polymer has a polymer having a linear or cyclic skeleton such as poly (meth) acrylate type, polyvinyl type, polysiloxane type, polyether type and polymalonate type as a main chain, and a side chain Or a liquid crystal polymer having a mesogenic component bound thereto, or a mixture of these.

In addition, the mesogen component is composed of two or more aromatic rings or aliphatic rings and a linking group that links them.
As an aromatic ring, a benzene ring, a naphthalene ring, etc. are mentioned, As an aliphatic ring, a cyclohexane ring etc. are mentioned. In addition, these aromatic rings or aliphatic rings may have a substituent.
As a linking group, a single bond, -O-, -COO-, -OCO-, -N = N-, -NO = N-, -C = C-, -CO-C = C-, -CH = N -, An alkylene group etc. are mentioned.

  The photosensitive group may be chalcone group, coumarin group, cinnamoyl group, cinnamylidene group, biphenyl acryloyl group, furyl acryloyl group, naphthyl acryloyl group, derivatives thereof or the like. Further, the mesogen component may form a photosensitive group, in which case, for example, the photosensitive group is a functional group that exhibits photosensitivity by binding of a benzene ring by a predetermined linking group (for example, a linking group May be —N = N—, —CO—C = C—, —C = C— and the like).

For example, as a combination of compounds capable of forming a photosensitive liquid crystal polymer,
(I) A combination of a compound having a photosensitive group and one condensable group with a compound having a mesogen component and the other condensable group,
(Ii) A combination of a compound having a photosensitive group and capable of forming a mesogenic component with one of the condensing groups and a compound capable of forming a mesogenic component with the other condensing group,
(Iii) A combination of a compound having a mesogenic component and capable of forming a photosensitive group with one of the condensable groups and a compound capable of forming a photosensitive group with the other condensable group,
(Iv) A combination of a compound capable of forming both a photosensitive group and a mesogenic component with one condensable group and a compound capable of forming both a photosensitive group and a mesogenic component with the other condensable group, etc. It can be mentioned.

  Among these, the combination of (iv) is preferable from the viewpoint of excellent solubility in a solvent. For example, as a combination of (iv), an aromatic amine compound and an aromatic aldehyde compound can be suitably used. The aromatic amine compound and the aromatic aldehyde compound form a benzylidene aniline compound by dehydration condensation as shown in the following reaction formula 1.

  This benzylidene aniline compound has a rigid molecular structure and becomes an effective mesogenic component for developing liquid crystallinity. Moreover, the carbon-nitrogen double bond contained in the benzylidene aniline compound has photoisomerization reactivity.

  The compound before the condensation reaction may be a compound having a melting point lower than normal temperature (for example, 25 ° C.) and liquid at normal temperature. In addition, the compound before condensation may be a compound that is solid at normal temperature. Usually, the compound before condensation has higher solubility in the solvent than the reaction product after condensation. Therefore, the compound before the condensation reaction can be used as a solution dissolved in various common organic solvents.

Moreover, when forming these compounds into a film, the production amount of the photosensitive group which arises by condensation reaction can be adjusted by changing mixing ratio. For example, one of the compounds capable of forming a photosensitive liquid crystal polymer is a high molecular weight compound (for example, molecular weight: 12,000 to 150,000) and the other is a low molecular weight compound (for example, molecular weight: 50 to 200) In this case, the molar ratio of the reactive group of the polymer compound to the low molecular weight compound is, for example, about 70/30 to 5/95, preferably about 60/40 to 10/90, more preferably about 55/45 to 15/85. It may be.
In the film in which the generation amount of such a photosensitive group is changed, it is also possible to adjust the anisotropy of the film generated by the irradiation of the linearly polarized ultraviolet light or the subsequent heating.

  The organic solvent is preferably a non-halogen solvent, and examples thereof include alcohol solvents such as ethanol, propanol and butanol, ketone solvents such as acetone, 2-butanone, methyl isobutyl ketone, cyclohexanone and cyclopentanone, and ethyl acetate Ester solvents such as butyl acetate and methoxypropyl acetate, diethyl ether, ethylene glycol monoethyl ether, diethylene glycol monoethyl ether, diethylene glycol dimethyl ether, ether solvents such as propylene monomethyl ether, hexane, cyclohexane, methylcyclohexane, toluene, xylene, etc. Hydrocarbon solvents, nitrile solvents such as acetonitrile, amide solvents such as N-methylpyrrolidone and dimethylacetamide, and the like. These solvents may be used alone or in combination of two or more.

  The solution (coating solution) used when forming a film may be, for example, a solution (mixed solution) in which at least two of the condensation-reactive compounds are dissolved in a solvent, or each compound may be used. It may be a solution (single solution) dissolved individually in a solvent. In the case of a single solution, film formation is separately performed, but in order to carry out a condensation reaction between the compounds, each compound is formed so that at least an overlapping portion exists.

At the time of film formation, the coating solution may be applied to the support. As a support body, it selects suitably from inorganic substances, such as various polymer films, glass, a quartz board | substrate, and is used. For example, as a polymer film, a cellulose-based polymer film such as polyethylene terephthalate film, diacetyl cellulose and triacetyl cellulose, a polycarbonate-based polymer film such as bisphenol A / carbonic acid copolymer, polyethylene, polypropylene and ethylene / propylene copolymer Linear or branched polyolefin films, polyamide-based films, imide-based polymer films, sulfone-based polymer films and the like. The condensation reactive compound can expand the range of selectivity of the organic solvent, so that, for example, even if the support is a polymer film, it is possible to carry out film formation in which damage to the support is suppressed. Become.
In addition, when using a liquid crystal polymer film in an optically anisotropic element or a liquid crystal aligning film, you may use a transparent thing among transparent bodies as a transparent base material.

  As a coating method, for example, a method such as gravure coating, flexo coating, die coating, bar coating, spin coating, or direct writing using an inkjet printer can be used.

  Moreover, when forming into a film separately the solution (single solution) which dissolved each compound separately in the solvent, for example, one side is apply | coated on the whole surface, it forms into a film, and the other is used using the printing method or a printer. If patterning application is performed, it is also possible to form a liquid crystal alignment layer or a layer having a phase difference only in the region where the other is applied.

  Furthermore, when two types of compound film forming solutions are separately applied, a high molecular weight compound (for example, polymer) solution is first applied, and then a low molecular weight compound (for example, monomer) is applied to the high molecular weight compound coating film. It is preferable to apply it to a high molecular weight compound because the low molecular weight compound can be efficiently attached to the high molecular weight compound.

[Condensation reaction process]
In the condensation reaction, in the film obtained in the film forming step, the compound is subjected to a condensation reaction to form a photosensitive liquid crystal polymer.

  The photosensitive liquid crystal polymer may be, for example, a side chain type liquid crystal polymer having the following structure in the side chain.

In each of the chemical formulas (2) and (3), n is an integer of 1 to 12, m is an integer of 1 to 12, and p is an integer of 1 to 12, and X or Y is -COO- or -OCO-. Or -N = N-, respectively, and W ₁ and W ₂ each represent a chalcone group, a cinnamylidene group, a biphenyl acryloyl group, a furyl acryloyl group, a naphthyl acryloyl group, a cinnamic acid group, a naphthyl acrylic acid group or derivatives thereof Represent.

(Wherein, Z represents -CO-C = C-, -C = N-, or -N = N-, and R represents a hydrogen atom, a halogen atom, -CN, an alkyl group (for example, C _1-6) An alkyl group, preferably a C _1-4 alkyl group, or an alkyloxy group (for example, a C _1-6 alkyloxy group, preferably a C _1-4 alkyloxy group) is shown.

Among these side chains, preferred are side chains having a photosensitive group represented by the following formula.

(Wherein, R is a hydrogen atom, a halogen group, -CN, an alkyl group or an alkyloxy group)

  The conditions for the condensation reaction can be appropriately set according to the type of compound. The condensation reaction may be carried out at normal temperature or may be carried out under heating. When heated, the condensation reaction can be promoted. The heating temperature is preferably set below the boiling point or sublimation point of each compound.

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

  The photosensitive liquid crystal polymer film produced by the condensation reaction is preferably insoluble in the solvent for dissolving the compound before the condensation reaction.

[Light irradiation process]
In the light irradiation step, the photosensitive liquid crystal polymer formed in the condensation reaction step is irradiated with light capable of anisotropically orienting the mesogen portion in the photosensitive liquid crystal polymer. Such light may be linearly polarized light or elliptically polarized light, preferably linearly polarized light. By the light irradiation step, the film becomes anisotropic due to the axial selective photoreaction. When liquid crystal molecules come into contact with the film, the film functions as a liquid crystal alignment film that induces the alignment of the liquid crystal molecules due to the anisotropy of the film.

  In order to proceed with this photoreaction, it is necessary to irradiate light of a wavelength at which the portion of the photosensitive group can react. Although a wavelength can be suitably set according to the kind of photosensitive group, generally it is 200-500 nm, and in many cases, the effectiveness of 250-400 nm is high. The photoreaction includes a photodimerization reaction, a photofleece transfer reaction, a photoisomerization reaction and the like, and preferably a photoisomerization reaction.

  For example, in the case of a benzylidene aniline compound, a photoisomerization reaction occurs in an axial selective manner as shown in reaction formula 2 by irradiation with light having linear polarization. When the side chain type polymer film containing the benzylidene aniline compound is irradiated with polarized ultraviolet light, the film becomes anisotropic due to axially selective photoisomerization.

[Heating process after light irradiation]
Moreover, after irradiating light, you may perform the heating process which heats a light irradiation film | membrane as needed. The heating step enables the liquid crystal polymer in the film to perform molecular motion. When heating a film that has generated anisotropy due to axially selective photoisomerization, the material itself has liquid crystallinity, and along the side chain that did not cause photoisomerization in the film by molecular motion after light irradiation. Orientation is induced.

  As a result, it becomes a film in which the side chains are uniformly oriented in the direction perpendicular to the electric field vibration direction of the polarized light component (for example, linearly polarized light) irradiated in the whole film, and the anisotropy of the film itself is amplified. The amplification of the anisotropy causes the enhancement of the liquid crystal alignment ability and the optical anisotropy (birefringence) of the film itself.

  The heating temperature is equal to or higher than the liquid crystal phase transition temperature of the material (liquid crystal polymer) forming the film itself, and is preferably set to equal to or lower than the isotropic phase transition temperature. The heating time can be appropriately set according to the type of liquid crystal polymer, heating temperature, etc., and may be, for example, in the range of 1 minute to 60 minutes, preferably about 3 minutes to 40 minutes, Preferably, it may be about 5 minutes to 20 minutes.

  Furthermore, after heating in this manner, when the film in which the rigid portion is oriented is cooled to below the softening point of the material, the molecules are frozen and a film in which the rigid portion is oriented is obtained. From the viewpoint of enhancing the reorientation, the cooling is preferably performed by normal standing cooling.

  As described above, a film is formed using at least two types of compounds that have high solubility in common organic solvents and at the same time generate a condensation reaction that forms a photosensitive functional group, and after the film formation, the condensation reaction is advanced It is possible to form a film to which the formation of a liquid group and the liquid crystallinity are imparted. The molecularly oriented film produced by the process including the step of irradiating the film with linearly polarized light functions as a liquid crystal alignment film or an optically anisotropic element (for example, a retardation film). Therefore, in the method of manufacturing a liquid crystal alignment film or an optically anisotropic element to which liquid crystal alignment ability is imparted by light irradiation, the problem of the prior art that the selection range of the solvent at the time of film formation is limited is solved. it can.

  Therefore, the liquid crystal polymer film according to the second configuration of the present invention is a liquid crystal polymer film produced by such a production method, and it has optical anisotropy or has liquid crystal alignment ability, Alternatively, it is a liquid crystal polymer film having liquid crystal alignment ability and optical anisotropy.

  For example, an optically anisotropic element according to a third configuration of the present invention is an optically anisotropic element including a transparent substrate and a liquid crystal polymer film formed on the transparent substrate. Or an optically anisotropic element in which the liquid crystal polymer film is the film described above.

  The fourth configuration of the present invention is a liquid crystal alignment film comprising a transparent substrate and a liquid crystal polymer film formed on the transparent substrate, wherein the liquid crystal polymer film is described above. It is a liquid crystal alignment film which is a film.

  Furthermore, the 5th structure of this invention is a liquid crystal display element provided with a pair of liquid crystal aligning film and a liquid crystal layer arrange | positioned between a pair of said optical elements, Comprising: The said liquid crystal aligning film was described above It is a liquid crystal display element which is a film.

  Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited by the examples. The synthetic methods for the materials used in the examples of the present invention are shown below.

(Monomer 1)
4- (6-hydroxyhexyloxy) benzaldehyde was synthesized by heating 4-hydroxybenzaldehyde and 6-chloro-1-hexanol under alkaline conditions. A large excess of methacrylic acid was added to this product in the presence of p-toluenesulfonic acid to cause esterification reaction, and monomer 1 represented by the chemical formula 6 was synthesized.

(Polymer 1)
The polymer 1 was obtained by dissolving the monomer 1 in THF and polymerizing by adding AIBN (azobisisobutyronitrile) as a reaction initiator. The polymer 1 was liquid at normal temperature and had solubility in common solvents such as acetone and 2-butanone.

(Compound 1)
As Compound 1, commercially available p-anisidine (manufactured by Tokyo Chemical Industry Co., Ltd., hereinafter the same) was used as it was. This compound 1 was soluble in common solvents such as ethers, alcohols, and acetone.

Example 1
Polymer 1 and p-anisidine were dissolved in acetone at a weight ratio of 1: 1 to prepare a solution. This solution was coated on a quartz substrate using a spin coater to a thickness of about 0.3 μm. The substrate was dried at room temperature and then heated at 100 ° C. for 10 minutes for dehydration condensation to form a photosensitive liquid crystal polymer film. This polymer film was insoluble in acetone. Subsequently, the substrate was irradiated with ultraviolet light from a high-pressure mercury lamp at 5 J / cm ² as linearly polarized light through a Glan-Taylor prism. After irradiation, heat treatment was performed at 130 ° C. for 10 minutes. The polarized UV-vis absorption spectrum of this film is shown in FIG. From this FIG. 1, it was confirmed that the absorption spectrum had an anisotropy due to the irradiation after the application, and further that the anisotropy was enhanced by the subsequent heat treatment.
When this substrate was observed under a polarizing plate crossed Nicol, it was confirmed that birefringence was caused.
In addition, two glass substrates on which such a film was formed were made to face each other to produce a cell, a liquid crystal material ("E7", manufactured by Merck Ltd.) was filled between the substrates, heated at 100 ° C, and cooled. . In the liquid crystal cell produced in this manner, it was confirmed that the filled liquid crystal material was aligned.

(Example 2)
Polymer 1 was dissolved in acetone to prepare a solution. This solution was coated on a quartz substrate using a spin coater to a thickness of about 0.3 μm. Next, p-anisidine was dissolved in methanol to form a solution, and the solution was applied onto a film of polymer 1 and dried. After drying, the film was heated at 100 ° C. for 10 minutes for dehydration condensation to form a photosensitive liquid crystal polymer film. The coating after heat treatment after application of p-anisidine was insoluble in the solvent.
The UV-vis absorption spectrum of the coating film (B) after heat-processing, after apply | coating p-anisidine to the coating film (A) which applied and dried the coating film (A) after coating the polymer 1 in FIG. 2 is shown. As shown in FIG. 2, the absorption spectra of the coated film (A) dried after application of the polymer 1 and the coated film (B) after heat treatment after application of p-anisidine to the coated film (A) are compared. In addition, in the coating film (B), it was confirmed that absorption having a peak around 350 nm was newly developed, and the absorption edge also extended to around 400 nm. Moreover, in FIG. 3, the infrared absorption spectrum of a coating film (A) and a coating film (B) is shown. In this FIG. 3, the disappearance of the peak derived from the C = O bond around 1680 cm ⁻¹ was confirmed. From these, it can be estimated that the photosensitive group (Schiff base) is formed by dehydration condensation. Subsequently, the substrate was irradiated with ultraviolet light from a high-pressure mercury lamp at 5 J / cm ² as linearly polarized light through a Glan-Taylor prism. After irradiation, heat treatment was performed at 130 ° C. for 10 minutes. The polarized UV-vis absorption spectrum of this film is shown in FIG. From this FIG. 4, comparing the absorption spectra of the film after application heating of p-anisidine and the film subjected to heat treatment after irradiation, in the film subjected to heat treatment after irradiation, in the absorption spectrum, a direction perpendicular to the polarization electric field direction and It could be confirmed that anisotropy occurred between

When this substrate was observed under a polarizing plate crossed Nicol, it was confirmed that birefringence was caused.
Further, two glass substrates on which such a film was formed were opposed to each other to prepare a cell, a liquid crystal material (E7 manufactured by Merck) was filled between the substrates, heated at 100 ° C., and cooled. In the liquid crystal cell produced in this manner, it was confirmed that the filled liquid crystal material was aligned.

  From Example 1 and Example 2, when forming into a film using the solution which mixed the at least 2 types of compounds which produce the condensation reaction which forms a photosensitive functional group (Example 1), or each compound separately In any case of forming a film (Example 2), a photosensitive side chain type liquid crystal polymer film can be formed by advancing the condensation reaction of the compound in the coating film, and this film is irradiated with light or irradiated with light and heated. It was confirmed that the liquid crystal alignment film and the retardation film can be produced by cooling. Here, since at least two types of compounds that cause a condensation reaction to form a photosensitive functional group have high solubility in a solvent at the time of film formation, or the compound itself is a liquid, so the solvent used in coating is It is possible to expand the selection range of Therefore, in these examples, although being a liquid crystal polymer material, it has been proved that a liquid crystal alignment film or a retardation film can be efficiently produced using a common organic solvent.

(Example 3)
A solution was prepared by dissolving Polymer 1 and p-anisidine in acetone at a molar ratio of 1: 0.5 to 1: 5. These solutions were applied onto a quartz substrate using a spin coater to a thickness of about 0.3 μm and dried at room temperature. Next, the substrate coated with these solutions was heated at 100 ° C. for 10 minutes. The UV-vis absorption spectrum of the coating film after heat processing is shown in FIG. The absorption intensity in the vicinity of 350 nm was changed depending on the molar ratio of polymer 1 and p-anisidine, and it was confirmed that the amount of photosensitive groups generated by the condensation reaction was changed. Subsequently, the substrate was irradiated with ultraviolet light from a high-pressure mercury lamp as linearly polarized light through the Glan-Taylor prism, with the irradiation amount changed to 0.01 to 500 J / cm ² . The change in degree of orientation of the film (as calculated from the polarized UV-vis absorption spectrum at 330 nm) at each irradiation dose is shown in FIG. From this FIG. 6, it was confirmed that the degree of orientation can be adjusted by the mixing ratio of the polymer 1 and p-anisidine.

  As described above, in the present invention, a liquid crystal polymer film having optical anisotropy and / or liquid crystal alignment ability can be efficiently produced without limiting the type of solvent. The liquid crystal polymer film of the present invention is suitably used not only as a retardation film, an optical compensation film, etc., but also as a liquid crystal alignment film by utilizing the orientation of the liquid crystal polymer. Can.

  As described above, although the preferred embodiments of the present invention have been described with reference to the drawings, various additions, modifications, or deletions can be made without departing from the spirit of the present invention, and such modifications are also possible. Included in the scope of

Claims (5)

A solution containing at least two compounds capable of forming a liquid crystal polymer having a photosensitive functional group (hereinafter referred to as a photosensitive liquid crystal polymer) is formed into a film by condensation reaction, or a solution of each compound is separately prepared. A film forming step of forming a film;
A condensation reaction step of subjecting the compound to a condensation reaction to form a photosensitive liquid crystal polymer in the film obtained in the film forming step;
Irradiating the obtained photosensitive liquid crystal polymer with light capable of anisotropically orienting the mesogen portion in the liquid crystal polymer;
A method of producing a liquid crystal polymer film, comprising at least   The method according to claim 1, further comprising a heating step of heating the light irradiation film.   The method for producing a liquid crystal polymer film according to claim 1 or 2, wherein a functional group having photosensitivity is formed by a condensation reaction of an aromatic amine compound and an aromatic aldehyde compound. The method according to any one of claims 1 to 3, wherein the liquid crystal polymer is a side chain type liquid crystal polymer, and a functional group having photosensitivity represented by the following chemical formula 1 is formed on the side chain. Method of producing a polymer membrane.

(Wherein, R is a hydrogen atom, a halogen group, -CN, an alkyl group or an alkyloxy group)   The method according to any one of claims 1 to 4, wherein the solvent for preparing the solution is a non-halogen solvent.

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