JP2005173547A - Method for manufacturing optically anisotropic substance - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optically anisotropic substance usable as an optical retardation film excellent in durability by a simple and easy method by avoiding contamination in rubbing thereby solving the problem that only alignment parallel to the traveling direction of a film is imparted. <P>SOLUTION: In a method for manufacturing the optically anisotropic substance, a multilayer film of an optically alignable polymerizable composition layer (A) which produces liquid crystal aligning ability upon photoirradiation and a polymerizable liquid crystal composition layer (B) is formed on a substrate and both the layers are polymerized in a state in which the liquid crystal composition having a polymerizable group is aligned. A method is preferred in which the layer (A) is formed, and after allowing the layer (A) to produce liquid crystal aligning ability, the polymerizable liquid crystal composition layer (B) is formed on the layer (A) and both the layers are polymerized, or a method is preferred in which the layer (B) is formed on the layer (A), and while or after allowing the layer (A) to produce liquid crystal aligning ability, both the layers are polymerized. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for producing an optical anisotropic body obtained by polymerizing a polymerizable liquid crystal composition in an aligned state.

An STN liquid crystal display (LCD) can display a large capacity by time-division driving with a simple matrix electrode structure. However, there is a problem that the screen is colored due to the retardation applied when passing through the liquid crystal, and a retardation film is used to solve this problem.
In addition, the TFT-LCD adopts the TN mode in which the alignment state of the liquid crystal molecules is twisted by 90 °, the response speed is fast (several tens of milliseconds), the white display can be easily obtained, and the display contrast is high. Therefore, it is the most powerful method for improving image quality compared to other types of LCD. However, because twisted nematic liquid crystal is used, there is a problem in viewing angle characteristics that the display color and display contrast change depending on the viewing direction due to the principle of the display method. To solve this problem, a retardation film is used. Yes.

  These retardation films are not limited to the above-mentioned LCD, but are IPS (In-Plane Switching) type LCD, FLC (Ferroelectric Liquid Crystal) type LCD, OCB (Optically Compensated Bend) type LCD, VA (Vertically Aligned EC) type LCD. (Electrically Controlled Birefringence) type LCD, HAN (Hybrid Aligned Nematic) type LCD, GH (Guest-Host) type LCD, and other types of LCDs are also required for the purpose of eliminating the viewing angle dependency. There is a need for a retardation film suitable for each method.

  In any case, since the liquid crystal has optical anisotropy, the image has viewing angle dependency, so it is necessary to improve the display quality by using some compensation film. Further, a retardation film that is necessary for a reflective or transflective liquid crystal display such as a quarter-wave plate is also used.

  Conventionally, a birefringent stretched film has been used for the retardation film, but in recent years, as a retardation film having more complicated optical properties, a polymerizable liquid crystal is applied on a substrate provided with an alignment film, Optical anisotropic bodies have been developed in which liquid crystal molecules are cured in an aligned state. (For example, see Patent Document 1.) This is a method in which a polymer film such as polyimide is provided on a substrate, and a polymerizable liquid crystal is applied on an alignment film that is rubbed (rubbed) with a cloth or the like in one direction. The liquid crystal molecules are aligned in the rubbing direction and then polymerized to fix the alignment. The optical properties that cannot be obtained with a stretched birefringent film due to the combination of the alignment direction of the alignment film and the alignment mode of the polymerizable liquid crystal Is obtained.

However, the rubbing alignment film has a problem of causing scratches and dust during the rubbing process. Dust generation can be removed by washing or the like, but scratches cannot be removed. Therefore, the optical uniformity of the laminated liquid crystal film may be greatly impaired.
Furthermore, in order to remove dust, cleaning or the like must be performed, and there is a problem that the manufacturing process becomes complicated. In addition, since the orientation is performed by the rubbing roll, it is possible to change the direction within a slight angle range, but in practice, only the orientation parallel to the traveling direction can be provided. Therefore, when the retardation film to be bonded to the liquid crystal display cell is cut out from the original fabric, the orientation direction and the cutting direction cannot be made parallel, and there is a problem that a large amount of unusable film is generated.

  A photo-alignment film is known as an alignment film that is not rubbed. The photo-alignment method is one of alignment methods in which liquid crystal molecules can be aligned without rubbing, and the film formed on the substrate is irradiated with light, and liquid crystal alignment ability is generated in the film in a non-contact manner. be able to. The alignment can be controlled by the direction of light, and unlike the rubbing method, it has the characteristic that there is no possibility of scratches or dust generation in principle, so a retardation film using a liquid crystal having a polymerizable group is created. In the above, the degree of freedom in controlling the alignment state is increased, and there is no light leakage due to scratches, and a uniform film can be formed.

  For example, after applying a photo-alignment film material containing a dichroic dye having two or more polymerizable groups in one molecule on a substrate and irradiating polarized light to impart a photo-alignment function, heating or light A photo-alignment film obtained by polymerizing a polymerizable group by irradiating a polymer, or a monomer such as 4,4-bisacryloyloxystilbene (for example, see Patent Document 2) is applied on a substrate, and is anisotropic. A photo-alignment film obtained by irradiating and reacting with various light is known (see, for example, Patent Document 3). However, the optical anisotropic body obtained using these photo-alignment films has a problem that the interface between the photo-alignment film and the polymerizable liquid crystal layer is peeled off, resulting in poor durability.

  As an optically anisotropic material having excellent durability, a polyimide coating film having a polymerizable group provided on a substrate is rubbed, and a discotic liquid crystal having a polymerizable group is applied thereon, and a polyimide alignment film and disco An optical compensation sheet excellent in durability, which is formed by chemically bonding an optically anisotropic layer made of a tick liquid crystal via an interface, is known. However, since the method uses a rubbing film, the problem derived from the rubbing film has not been solved as before. The optical compensation sheet relates to a vertical alignment film in which the diameter direction of the discotic liquid crystal molecules is aligned in a direction perpendicular to the substrate, and by introducing a long alkyl chain, an aliphatic chain, or the like. Since the surface energy on the surface of the alignment film is lowered, liquid crystal molecules tend to aggregate on the surface of the vertical alignment film, which makes it difficult to stack in a thin film state.

Japanese Patent Application Laid-Open No. 5-215921 JP 2002-250924 A JP 2001-48904 A JP 2001-89657 A

  The problem to be solved by the present invention is to avoid contamination of the retardation film due to scratches and dust generation during rubbing treatment, and in the process of producing the retardation film, the rubbing direction is limited with respect to the traveling direction of the film, The object is to solve the problem that, in effect, only an orientation parallel to the running direction can be imparted, and to provide an optical anisotropic body that can be used as a retardation film having excellent durability by a simple method.

  The inventors of the present invention have solved the above-mentioned problems by using a film that generates liquid crystal alignment ability by light irradiation and setting the alignment conditions and polymerization conditions to specific methods. That is, a film (layer) comprising a compound having a liquid crystal alignment ability by light irradiation and a compound having both a polymerizable group and a liquid crystal compound having a polymerizable group. A liquid crystal compound having a polymerizable group and a film (layer) formed of the compound having a liquid crystal alignment ability while forming a laminated film with the layer on the substrate and maintaining the alignment state of the liquid crystal compound having the polymerizable group It has been found that by polymerizing the layers, a bonding relationship can be introduced between the two layers, and an optical anisotropic body excellent in adhesion and durability can be easily obtained.

  That is, the present invention forms a laminated film of a photoalignable polymerizable composition layer (A) that generates liquid crystal aligning ability by light irradiation and a polymerizable liquid crystal composition layer (B) on a substrate, and the polymerizable property. Provided is a method for producing an optical anisotropic body in which both layers are polymerized in a state where a liquid crystal composition having a group is aligned.

  By the production method of the present invention, it is possible to easily obtain an optical anisotropic body that is excellent in durability and uniform and can be used as a retardation film without light leakage. In particular, the photo-alignment polymerizable composition layer has the disadvantage that the anchoring force of the photo-alignment film (the magnitude of the interaction between the alignment film and the liquid crystal molecules) is weaker than that of the rubbing alignment film and the alignment regulation force is weak It can also be improved by connecting the liquid crystal layer polymerizable liquid crystal composition layer with a covalent bond.

(Photoalignable polymerizable composition layer (A) in which liquid crystal alignment ability is produced by light irradiation)
The photo-alignable polymerizable composition layer (A) (hereinafter abbreviated as layer (A)) that generates liquid crystal alignment ability upon irradiation with light is a group that generates liquid crystal alignment ability when irradiated with light (hereinafter referred to as photo-alignment group). Abbreviated).
In the present invention, the photo-alignment group is a molecular orientation induction or isomerization reaction (eg, azobenzene group) or dimerization reaction (eg, cinnamoyl group) due to the Weigert effect resulting from photodichroism caused by light irradiation. ), Photocrosslinking reaction (eg, benzophenone group), or photodecomposition reaction (eg, polyimide group), which represents a group that causes a photoreaction that is the origin of liquid crystal alignment ability. Among them, those using molecular orientation induction or isomerization reaction, dimerization reaction, or photocrosslinking reaction due to Weigert effect due to photodichroism are excellent in alignment property and can easily align polymerizable liquid crystals. preferable.
The photo-alignment group is not particularly limited, but among them, at least one double bond selected from the group consisting of C = C, C = N, N = N, and C = O (however, it forms two aromatic rings). A group having (excluding a heavy bond) is particularly preferably used.

Examples of groups having a C═C bond as these photo-alignable groups include groups having a structure such as a polyene group, a stilbene group, a stilbazole group, a stilbazolium group, a cinnamoyl group, a hemithioindigo group, and a chalcone group. It is done. Examples of the group having a C═N bond include groups having a structure such as an aromatic Schiff base and an aromatic hydrazone. Examples of the group having an N═N bond include groups having a structure such as an azobenzene group, an azonaphthalene group, an aromatic heterocyclic azo group, a bisazo group, a formazan group, and those having a basic structure of azoxybenzene. Examples of the group having a C═O bond include groups having a structure such as a benzophenone group, a coumarin group, and an anthraquinone group. These groups may have a substituent such as an alkyl group, an alkoxy group, an aryl group, an allyloxy group, a cyano group, an alkoxycarbonyl group, a hydroxyl group, a sulfonic acid group, and a halogenated alkyl group.
Among them, an azobenzene group or anthraquinone group that exhibits photo-alignment by a photoisomerization reaction, or a benzophenone group, cinnamoyl group, chalcone group, or coumarin group that exhibits photo-orientation by a photodimerization reaction has a polarization necessary for photo-alignment. This is particularly preferable because the irradiation amount is small, and the obtained photo-alignment film has excellent thermal stability and stability over time.

  Examples of the polymerizable group include (meth) acryloyl group, (meth) acryloyloxy group, (meth) acrylamide group, vinyl group, vinyloxy group, azide group, chloromethyl group, epoxy group, and maleimide group. Among these, since photopolymerization and thermal polymerization are relatively easy, (meth) acryloyl group, (meth) acryloyloxy group, (meth) acrylamide group, vinyl group, vinyloxy group are preferable, (meth) acryloyl group, A (meth) acryloyloxy group or a (meth) acrylamide group is more preferable. Moreover, when it is a maleimide group, it can superpose | polymerize, without using a photoinitiator.

These polymerizable groups may be directly bonded to the photoalignable group or may be bonded via a linking group such as an alkylene group or a phenylene group. The linking group may have an ester bond, an ether bond, an imide bond, an amide bond or a urethane bond. Examples of such a linking group include a methylene group, ethylene group, trimethylene group, tetramethylene group, pentamethylene group, hexamethylene group, heptamethylene group, octamethylene group, nonamethylene group, decamethylene group, undecamethylene group, A linear alkylene group having 1 to 18 carbon atoms such as dodecamethylene group; 1-methylethylene group, 1-methyl-trimethylene group, 2-methyl-trimethylene group, 1-methyl-tetramethylene group, 2-methyl A branched alkylene group having 1 to 18 carbon atoms such as tetramethylene group, 1-methyl-pentamethylene group, 2-methyl-pentamethylene group, 3-methyl-pentamethylene group; phenylene such as p-phenylene group Group: 2-methoxy-1,4-phenylene group, 3-methoxy-1,4-phenylene group, 2-eth Linear or branched having 1 to 18 carbon atoms such as cis-1,4-phenylene group, 3-ethoxy-1,4-phenylene group, 2,3,5-trimethoxy-1,4-phenylene group, etc. And an alkoxyphenylene group having an alkoxyl group.
(Hereinafter, a compound having a photoalignable group and a polymerizable group is abbreviated as compound (C).)

The molecular weight of the compound (C) is preferably in the range of 1 × 10 ² to 1 × 10 ⁶ in terms of weight average molecular weight. However, if the molecular weight is too high, the photo-alignment group becomes difficult to move in the system and the sensitivity to light tends to decrease. Therefore, the range of 1 × 10 ² to 1 × 10 ⁵ is more preferable, and 1 × 10 A range of ^{2 to} 5 × 10 ³ is more preferable.

  Specifically, the compound (C) is preferably a compound represented by the general formula (1).

In the formula, R ¹ and R ² are each independently a polymerization selected from the group consisting of (meth) acryloyl group, (meth) acryloyloxy group, (meth) acrylamide group, vinyl group, vinyloxy group, and maleimide group. Represents a sex group. Of these, a (meth) acryloyl group, a (meth) acryloyloxy group, or a (meth) acrylamide group is preferable because photopolymerization and thermal polymerization are relatively easy. A maleimide group is more preferable because a polymerization initiator is not required.

In General Formula (1), X ¹ represents a linking group represented by — (A ¹ -B ¹ ) _m —, and X ² represents a linking group represented by — (B ² -A ² ) _n —. Represent. Here, A ¹ and A ² each independently represent a single bond or a divalent hydrocarbon group. Examples of the divalent hydrocarbon group include alkylene groups having 1 to 20 carbon atoms such as ethylene group, methylene group, propylene group, pentamethylene group and heptylene group; 3 to 3 carbon atoms such as cyclopropylene group and cyclohexylene group. 20 cycloalkylene group; arylene groups having 6 to 20 carbon atoms such as phenylene group and naphthylene group. Among these, an alkylene group is preferable and an alkylene group having 1 to 4 carbon atoms is more preferable.

B ¹ and B ² each independently represents a single bond, —O—, —CO—O—, —OCO—, —CONH—, —NHCO—, —NHCO—O—, or —OCONH—. m and n each independently represents an integer of 1 to 4. When m or n is 2 or more, a plurality of A ¹ , B ¹ , A ² and B ² may be the same or different. However, A ¹ or A ² sandwiched between two B ¹ or B ² is not a single bond. Specifically, when m is ^{2, - (A 1 -B 1} ) m - linking group represented _{by, -CH 2 CH 2 -O-CH} 2 CH 2 CH 2 CH 2 -CO-O- or _{represents -O-CH 2 CH 2 CH 2} -CO-O- and the like, when n is ^{2, - (B 2 -A 2} ) n - linking group represented by, -O-CO-Ph It represents the like - (phenylene _group) -O- _(CH 2) _6.

  Y represents a group having an azobenzene group, an anthraquinone group, a benzophenone group, a cinnamoyl group, a chalcone group or a coumarin group. Among these, a group having the following structure is preferable.

In the above structure, p _{1 to} p ₁₁ are each independently a hydrogen atom, a halogen atom, a halogenated alkyl group, a halogenated alkoxy group, a cyano group, a nitro group, an alkyl group, an alkoxy group, an aryl group, an allyloxy group, an alkoxy group. A carbonyl group, a carboxyl group, a sulfonic acid group, an amino group, or a hydroxy group is represented. However, the carboxyl group and the sulfonic acid group may form a salt with an alkali metal.
Among them, an azobenzene group is preferable, and an azobenzene structure having the following structure is particularly preferable.

In the above structure, p _{1 to} p ₄ are each independently a hydrogen atom, halogen atom, halogenated alkyl group, halogenated alkoxy group, cyano group, nitro group, alkyl group, alkoxy group, aryl group, allyloxy group, alkoxy group. A carbonyl group, a carboxyl group, a sulfonic acid group, an amino group, or a hydroxy group is represented. However, the carboxyl group and the sulfonic acid group may form a salt with an alkali metal. Among these, a carboxyl group, a sulfonic acid group, an amino group, a hydroxy group, or a salt thereof is preferable, and a carboxyl group, a sulfonic acid group, or a salt thereof is preferable.

  Specific examples of the compound represented by the general formula (1) include compounds described in JP-A No. 2002-250924 and JP-A No. 2002-317013. It can be easily synthesized.

  Since the compound represented by the general formula (1) has a low molecular weight, it is excellent in sensitivity to light when formed into a coating film. Therefore, liquid crystal alignment ability can be easily imparted by light irradiation. In addition, the polymerizable group has a higher degree of freedom than the polymerizable group bonded to the polymer, so the reaction rate is high, and the layer (A) that causes the liquid crystal alignment ability and the polymerizable liquid crystal composition layer (B) at the interface. It can react well and has excellent adhesion at the interface.

  Compound (C) is preferably used by dissolving in an appropriate solvent. The solvent is not particularly limited, but N-methylpyrrolidone (hereinafter abbreviated as NMP), butyl cellosolve, phenyl cellosolve, N, N-dimethylformamide (hereinafter abbreviated as DMF), γ-butyrolactone, dimethyl sulfoxide (hereinafter, abbreviated as “MP”). DMSO)), ethylene glycol, propylene glycol, toluene, tetrahydrofuran, chlorobenzene, dimethylacetamide and the like. Among these, a solution of NMP, butyl cellosolve, and DMF is particularly preferable because it has a good coating property on a substrate such as glass and a uniform film can be obtained. These solutions are preferably selected in consideration of applicability and the volatilization rate of the solvent after application, and two or more kinds can be mixed and used.

  Since the solvent is volatilized and removed after being applied to the substrate, when used, the solid content concentration of the compound (C) needs to be at least 0.2% by mass or more. Especially, the range of 0.3-10 mass% is especially preferable. Moreover, polymer materials such as polyvinyl alcohol and polyimide can be mixed within a range not impairing the effects of the present invention. (Hereinafter, the composition containing the compound (C) is abbreviated as a photo-alignment polymerizable composition)

(Polymerizable liquid crystal composition layer (B))
In the present invention, the liquid crystal compound having a polymerizable group constituting the polymerizable liquid crystal composition layer (B) (hereinafter abbreviated as layer (B)) exhibits liquid crystallinity alone or in a composition with another liquid crystal compound. If it is a compound which has a polymeric group, there will be no limitation in particular. For example, Handbook of Liquid Crystals (D. Demus, J. W. Goodbye, GW Gray, H. W. Spiss, V. Vill, edited by Wiley-VCH, 1998), Quarterly Chemical Review. 22, Liquid Crystal Chemistry (Edited by Chemical Society of Japan, 1994), or JP-A-7-294735, JP-A-8-3111, JP-A-8-29618, JP-A-11-80090, 1,4-phenylene group, 1,4-cyclohexene, as described in Kaihei 11-148079, JP-A 2000-178233, JP-A 2002-308831, and JP-A 2002-145830. A rod-like polymerizable liquid crystal compound having a rigid site called a mesogen in which a plurality of structures such as a silene group are connected, and a polymerizable functional group such as a (meth) acryloyl group, a vinyloxy group, and an epoxy group,

  Alternatively, for example, Handbook of Liquid Crystals (D. Demus, J. W. Goodby, GW Gray, H. W. Spiss, V. Vill, edited by Wiley-VCH, No. 1998) . 22. Liquid crystal chemistry (edited by Chemical Society of Japan, 1994) and discotic polymerizable compounds described in JP-A-07-146409. Among these, a rod-like liquid crystal compound having a polymerizable group is preferable because it can easily produce a liquid crystal having a temperature range around room temperature.

(Production method)
In the production method of the present invention, a laminated film of the above-mentioned layer (A) and the above-mentioned layer (B) is formed on a substrate, and the liquid crystal composition having the polymerizable group is aligned. Is polymerized.
Specific examples are given below. In addition, the following examples are reference examples to the last, and are not limited to these. Moreover, it can also manufacture combining this example.

1. Method 1 in which a photopolymerization initiator is added to the layer (B)
A layer (A) is formed by applying and drying a photo-alignable polymerizable composition not containing a polymerization initiator on a substrate, and the layer side (substrate side opposite to the layer forming side) or From the surface side of the layer (A), polarized light having a wavelength that can be absorbed by the photoalignable group of the compound (C) is irradiated to give liquid crystal alignment ability. When the photo-alignable group is a group utilizing molecular orientation induction or isomerization reaction by the Weigert effect, the liquid crystal is irradiated with non-polarized light having a wavelength that the group efficiently absorbs from the oblique direction. An alignment function may be given (this is the same for other embodiments. In addition, polarized light irradiated for alignment and non-polarized light obliquely with respect to the substrate are collectively referred to as “alignment light”) . Next, a polymerizable liquid crystal composition solution containing a photopolymerization initiator is applied and dried thereon to form a layer (B). The polymerizable liquid crystal of the layer (B) assumes the intended alignment state due to the effect of the liquid crystal alignment ability of the layer (A). Next, two layers of light having a wavelength that is absorbed by the added photopolymerization initiator are irradiated to advance curing of the polymerizable liquid crystal, and at the same time, photopolymerization existing at the interface between the layer (A) and the layer (B). Polymerization is carried out between the molecules of both layers by means of an initiator. Since radicals generated by the cleavage of the photopolymerization initiator can move between both layers, if a photopolymerization initiator is contained in either layer, the polymerizable groups present at the interface between the two layers are polymerized. Thus, the layer (A) and the layer (B) are covalently bonded, the adhesion at both interfaces is improved, and an optical anisotropic body excellent in durability can be obtained. Further, in this method, since the photoalignable polymerizable composition does not contain a photopolymerization initiator, there is no possibility that unexpected polymerization occurs during irradiation of alignment light or the like, and the alignment treatment can be performed uniformly.

2. Method 2 in which a photopolymerization initiator is added to the layer (B)
A photo-alignment polymerizable composition not containing a polymerization initiator is applied onto a transparent substrate and dried to form a layer (A), and then the layer (A) is not oriented, and a photo-polymerization initiator is included thereon. The polymerizable liquid crystal composition is applied and dried to form the layer (B).
Next, alignment light is irradiated from the transparent substrate side or from the surface side of the layer (B) to impart alignment ability to the layer (A). Since the polymerizable liquid crystal compound of the layer (B) is also aligned according to the provision of the alignment ability of the layer (A), the alignment ability can be further enhanced. In particular, from the layer (A) side, a method of irradiating oriented light having a wavelength that can be absorbed by the photoalignable group of the compound (C) or non-oriented light from an oblique direction to the substrate is preferable. In this method, the photo-alignment group in the layer (A) absorbs most of the irradiation light, the liquid crystal alignment ability is generated, and the molecules of the stacked layer (B) are aligned. As the irradiation progresses, the irradiation light passes through the layer (A) by the mechanism described below, reaches the layer (B), cleaves the photopolymerization initiator in the layer, and induces a polymerization reaction. Bonding between layer (A) and layer (B) also occurs. That is, when light irradiation is performed from the transparent substrate side, an isomerization reaction such as an azobenzene group is caused to induce molecular orientation by the Weigert effect. The orientation direction of the film changes to take an orientation state that minimizes absorption, so that the irradiation light gradually leaks into the layer (B), inducing polymerization of the layer (B). Similarly, even when a compound utilizing a dimerization reaction (eg, cinnamoyl group), photocrosslinking reaction (eg, benzophenone group), or photodecomposition reaction (eg: polyimide group) is used as the layer (A) The components oriented in this direction by light absorption are dimerized, photocrosslinked, photodecomposed, and the group that absorbs gradually decreases, so that the irradiation light leaks to the layer (B), and the polymerization of the layer (B) Induces. In this aspect, since the light to be irradiated serves as both alignment light and polymerization light, polymerization is performed while controlling the alignment, and an excellent alignment in which the alignment is not disturbed can be obtained. If the alignment does not proceed sufficiently with the light, the polymerization light may be superimposed and irradiated.
Therefore, the layer (A) and the layer (B) are covalently bonded, the adhesion at both interfaces is improved, and an optical anisotropic body excellent in durability can be obtained. Also in this case, since the photo-alignable polymerizable composition does not contain a photopolymerization initiator, there is no possibility of unexpected polymerization during irradiation of alignment light, and the alignment process can be performed uniformly.

3. A method in which a photopolymerization initiator having a light absorption wavelength band different from the light absorption band of compound (C) is added to one or both of the polymerizable liquid crystal composition and the photoalignable polymerizable composition. After the photopolymerizable composition solution is applied and dried on the substrate to form the layer (A), the wavelength that can be absorbed by the photoalignable group of the compound (C) from the substrate side or the surface side of the layer (A) The liquid crystal alignment ability is given by irradiating the alignment light or non-alignment light from the oblique direction to the substrate. When the polymerizable liquid crystal composition solution is applied and dried thereon to form the layer (B), the polymerizable liquid crystal compound is in the intended alignment state. Next, the laminated two layers are irradiated with light having a wavelength that is absorbed by the added photopolymerization initiator, and bonds between molecules at the interface between the layer (B) and the layer (A). The curing of each of C) is also advanced. Also by such an operation, the layer (A) and the layer (B) are covalently bonded, the adhesion at both interfaces is improved, and an optical anisotropic body excellent in durability can be obtained.
After laminating the layer (A) and the layer (B), the above-described alignment light irradiation and polymerization light irradiation may be performed.

4). A method in which a thermal polymerization initiator is added to one or both of a polymerizable liquid crystal composition and a photoalignable polymerizable composition. A layer (A) is formed by applying and drying a photoalignable polymerizable composition solution on a substrate. After the formation, from the substrate side or the surface side of the layer (A), the alignment light having a wavelength that can be absorbed by the photoalignable group of the compound (C) or non-alignment light from an oblique direction is irradiated to the substrate. Provides liquid crystal alignment ability. A layer (B) is formed thereon, both layers are heated to cleave the thermal polymerization initiator to advance curing of both layers, and at the same time, heat existing at the interface between the layers (B) and (A). Polymerization is performed between the molecules of both layers by a polymerization initiator. The radicals generated by the cleavage of the thermal polymerization initiator can move in both layers, so if they are contained in either layer, the polymerizable groups present at the interface between both layers can be polymerized. The layer (A) and the layer (B) are covalently bonded, the adhesion at both interfaces is improved, and an optical anisotropic body excellent in durability can be obtained.
After laminating the layer (A) and the layer (B), the above-described alignment light irradiation and polymerization light irradiation may be performed.

5. Method of Using Thermal Polymerization Initiator and Photopolymerization Initiator After Forming Layer (A) by Applying and Drying Photoalignable Polymerizable Composition Containing Thermal Polymerization Initiator on Substrate, then Substrate Side or Layer (A ) From the surface side, alignment light having a wavelength that can be absorbed by the photo-alignment group of the compound (C) or non-alignment light from an oblique direction is applied to the substrate to give liquid crystal alignment ability. Next, a layer (B) containing a photopolymerization initiator is formed on the layer, and the wavelength that the photopolymerization initiator absorbs while heating the two laminated layers to an appropriate temperature at which the thermal polymerization initiator is cleaved. By irradiating the light, the curing of both layers proceeds and at the same time the molecules of both layers are polymerized.

Alternatively, a photopolymerization initiator having a light absorption wavelength band different from that of the photoalignable polymerizable composition itself is added to the photoalignable polymerizable composition, and the layer (A) is coated on the substrate and dried. After formation, liquid crystal alignment is performed by irradiating alignment light that can be absorbed by the photoalignable group of the compound (C) or non-alignment light from an oblique direction to the substrate from the substrate side or the surface side of the layer (A). Give the ability. Next, a layer (B) added with a thermal polymerization initiator is formed on the layer, and both layers are simultaneously cured by irradiating light absorbed by the photopolymerization initiator while heating both layers. Polymerize between molecules. Also by such an operation, it is possible to obtain an optical anisotropic body having excellent durability by providing bonding between the layer (A) and the layer (B), improving the adhesiveness at both interfaces.
After laminating the layer (A) and the layer (B), the above-described alignment light irradiation and polymerization light irradiation may be performed.

(Application method)
Known methods for forming each layer on the substrate include spin coating methods, extrusion methods, gravure coating methods, die coating methods, bar coating methods, applicator methods and other printing methods, and flexographic methods. Can be used.

(substrate)
The substrate is not particularly limited as long as it is substantially transparent, and glass, ceramics, plastics and the like can be used. Examples of plastic substrates include cellulose, triacetyl cellulose, cellulose derivatives of diacetyl cellulose, polyesters such as polyethylene terephthalate and polyethylene naphthalate, polyolefins such as polypropylene and polyethylene, and polycarbonate. , Polyvinyl alcohol, polyvinyl chloride, polyvinylidene chloride, nylon, polystyrene, polyacrylate, polymethyl methacrylate, polyethersulfone, polyarylate and the like can be used.
The optical anisotropic body manufactured by applying to the substrate may be bonded to the substrate of the liquid crystal cell, the optical anisotropic body formed by application may be peeled off from the substrate and bonded to the substrate of the liquid crystal cell, An optical anisotropic body can also be formed directly on the glass substrate or plastic substrate of the liquid crystal cell.

(Optical alignment operation)
For imparting liquid crystal alignment ability to the layer (A) (hereinafter abbreviated as photoalignment operation), polarized light having a wavelength that can be absorbed by the photoalignable group of the compound (C) is applied to the coating film surface or the coating film surface. May be irradiated from the opposite substrate side, perpendicular to the surface or from an oblique direction. In addition, when the photo-alignable group is a group utilizing molecular orientation induction or isomerization reaction due to the Weigert effect, non-polarized light having a wavelength that the group efficiently absorbs from the coating film surface or the substrate side. The liquid crystal alignment function may be given by irradiating the surface from an oblique direction. Also, polarized light and non-polarized light may be combined.
The polarized light may be either linearly polarized light or elliptically polarized light, but it is preferable to use linearly polarized light having a high extinction ratio in order to perform photoalignment efficiently.

  Moreover, since it is necessary to use a polarizing filter in order to obtain polarized light, there is a disadvantage that the light intensity irradiated on the film surface is reduced. However, in the method of irradiating non-polarized light from an oblique direction with respect to the film surface, The irradiation apparatus does not require a polarizing filter, and there is an advantage that a large irradiation intensity can be obtained and the irradiation time for photo-alignment can be shortened. At this time, the incident angle of non-polarized light is preferably in the range of 10 ° to 80 ° with respect to the normal of the substrate. A range of 60 ° is most preferred.

The light to be irradiated may be light in a wavelength region in which the photoalignable group of the compound (C) has absorption. For example, when the photo-alignment group has an azobenzene structure, ultraviolet rays having a wavelength of 350 to 500 nm that have strong absorption due to the π → π ^* transition of azobenzene are particularly preferable. Examples of the light source for irradiation light include xenon lamps, high-pressure mercury lamps, ultra-high pressure mercury lamps, metal halide lamps, ultraviolet lasers such as KrF and ArF, and the like. In particular, when the photo-alignment group has an azobenzene structure, the ultra-high pressure mercury lamp is particularly preferable because the emission intensity of ultraviolet light at 365 nm is large. Ultraviolet linearly polarized light can be obtained by passing the light from the light source through a polarizing prism such as a polarizing filter, Glan-Thompson, and Glan-Teller. Moreover, it is particularly preferable that the irradiated light is substantially parallel light regardless of whether polarized light or non-polarized light is used. The light to be irradiated may be irradiated from the surface side of the layer (A) or the layer (B) or from the substrate side. In the case of irradiation from the substrate side, a transparent substrate is used as the substrate.
Among them, it is more preferable to irradiate from the substrate side because light that orients the photoalignable group can be directly irradiated to the photoalignable group.

  Further, when irradiating polarized light, if a photomask is used, the layer (A) can have liquid crystal alignment ability in two or more different directions in a pattern. Specifically, the substrate on which the layer (A) is formed is covered with a photomask, and the entire surface is irradiated with polarized light or non-polarized light to give liquid crystal alignment ability to the exposed portion in a pattern. By repeating this as many times as necessary, liquid crystal alignment ability can be produced in a plurality of directions. Next, the layer (B) is laminated, and the liquid crystal molecules are aligned on the substrate, and then the layers (A) and (B) are polymerized by irradiating ultraviolet rays, and the two layers are bonded.

Specific modes when using a photomask are shown in FIGS.
FIG. 1 is a plan view of an optical anisotropic body as seen from the normal direction of a substrate when a layer (A) is provided with an alignment pattern in which a plurality of different alignment regions are alternately arranged in the in-plane alignment direction. FIG. 2 is a plan view and a side view of an optically anisotropic body as viewed from the normal direction of a substrate when a layer (A) is provided with an alignment pattern in which a plurality of different alignment regions having different pretilt angles are alternately arranged. It is.
The direction of arrow 1 indicates the orientation direction of the layer (B) in the same orientation region. The layer (B) cured in a state of being aligned by the layer (A) in which the liquid crystal alignment ability is generated in a plurality of directions in an intended pattern shows a pattern based on the alignment of (A).

(polymerization)
The polymerization operation of the photo-alignable polymerizable composition and the polymerizable liquid crystal composition is generally performed by irradiation with light such as ultraviolet rays or heating.
When polymerization is performed by light irradiation, in order not to disturb the orientation state of the layer (A) already obtained, generally, the light absorption band of the compound (C), for example, an azobenzene skeleton or an anthraquinone skeleton It is preferable to carry out at a wavelength other than the absorption band of. Specifically, it is preferable to irradiate ultraviolet light of 320 nm or less, and most preferable to irradiate light having a wavelength of 250 to 300 nm. However, when the photo-alignment polymerizable composition and the polymerizable liquid crystal composition cause decomposition or the like due to ultraviolet light of 320 nm or less, it may be preferable to perform the polymerization treatment with ultraviolet light of 320 nm or more.
This light is preferably diffused light and unpolarized light so as not to disturb the orientation of the photoalignable group already obtained. Therefore, it is usually preferable to use a photopolymerization initiator having a light absorption wavelength band different from the light absorption band of the compound (C). On the other hand, when light for polymerization is irradiated from the same direction as the photo-alignment operation, any wavelength can be used because there is no fear of disturbing the alignment state of the photo-alignment material.

  As the photopolymerization initiator, known ones can be used. For example, 2-hydroxy-2-methyl-1-phenylpropan-1-one ("Darocur 1173" manufactured by Merck & Co., Inc.), 1-hydroxycyclohexyl phenyl ketone (Ciba Specialty Chemicals “Irgacure 184”), 1- (4-Isopropylphenyl) -2-hydroxy-2-methylpropan-1-one (Merck “Darocur 1116”), 2-methyl-1-[( Methylthio) phenyl] -2-morpholinopropane-1 (“Irgacure 907” manufactured by Ciba Specialty Chemicals). Benzylmethylketal ("Irgacure 651" manufactured by Ciba Specialty Chemicals). A mixture of 2,4-diethylthioxanthone (“Kayacure DETX” manufactured by Nippon Kayaku Co., Ltd.) and ethyl p-dimethylaminobenzoate (“Kayacure EPA” manufactured by Nippon Kayaku Co., Ltd.) -ITX ") and a mixture of ethyl p-dimethylaminobenzoate, acylphosphine oxide (" Lucirin TPO "manufactured by BASF), and the like. 10 mass% or less is preferable with respect to a composition, and, as for the usage-amount of a photoinitiator, 0.5-5 mass% is especially preferable.

  The light for polymerization may be irradiated from the surface of the layer (B) or from the substrate side, and may be optional, but it is unexpected to irradiate from the side where the photopolymerization initiator is added. This is preferable because there is little risk of occurrence.

  On the other hand, the polymerization by heating is preferably performed at a temperature at which the polymerizable liquid crystal composition exhibits a liquid crystal phase or at a temperature lower than that. In particular, when a thermal polymerization initiator that releases radicals by heating is used, the cleavage temperature is the above. It is preferable to use the one in the temperature range. In the case where the thermal polymerization initiator and the photopolymerization initiator are used in combination, the polymerization temperature is set so that the polymerization rate of both layers (A) and (B) does not greatly differ with the limitation of the temperature range. And each initiator is preferably selected. Although the heating temperature depends on the transition temperature from the liquid crystal phase to the isotropic phase of the polymerizable liquid crystal composition, it is preferably performed at a temperature lower than the temperature at which inhomogeneous polymerization is induced by heat. 300 degreeC is preferable, 30 to 200 degreeC is more preferable, and 30 to 120 degreeC is especially preferable. For example, when a polymeric group is a (meth) acryloyl group, it is preferable to carry out at a temperature lower than 90 degreeC.

  In the above case, it is preferable to use a thermal polymerization initiator as appropriate. As the thermal polymerization initiator, known and commonly used ones can be used. For example, methyl acetoacetate peroxide, cumene hydroperoxide, benzoyl peroxide, bis (4-t-butylcyclohexyl) peroxydicarbonate, t -Butyl peroxybenzoate, methyl ethyl ketone peroxide, 1,1-bis (t-hexyl peroxy) 3,3,5-trimethylcyclohexane, p-penta hydroperoxide, t-butyl hydroperoxide, dicumylpa Organic peroxides such as oxide, isobutyl peroxide, di (3-methyl-3-methoxybutyl) peroxydicarbonate, 1,1-bis (t-butylperoxy) cyclohexane, 2,2′-azo Bisisobutyronitrile, 2,2′-azobis (2, Azonitrile compounds such as 2-dimethylvaleronitrile), azoamidin compounds such as 2,2′-azobis (2-methyl-N-phenylpropion-amidin) dihydrochloride, 2,2′azobis {2-methyl-N- [1 , 1-bis (hydroxymethyl) -2-hydroxyethyl] propionamide}, alkyl azo compounds such as 2,2′azobis (2,4,4-trimethylpentane), and the like can be used. 10 mass% or less is preferable with respect to a composition, and, as for the usage-amount of a thermal-polymerization initiator, 0.5-5 mass% is especially preferable.

  The polymerization initiators such as the photopolymerization initiator and the thermal polymerization initiator described above may be included in either the layer (A) or the layer (B), and may be included in both. Since the interface between both layers is liquid, the polymerization initiator and radicals generated by the cleavage of the polymerization initiator can move to both layers to some extent. Therefore, if included in either layer, both layers can be polymerized at the same time, and the optically anisotropic body in which the layer (A) and the layer (B) excellent in durability are covalently bonded and laminated is obtained. Can be obtained.

  For example, the photo-alignable polymerizable composition does not contain a polymerization initiator, and when the polymerizable liquid crystal composition contains a polymerization initiator, the polymerization initiator slightly shifts from the layer (B) to the layer (A). Further, by applying light or heat, radicals generated in the polymerizable liquid crystal composition are transferred to the layer (A), and both layers and their interfaces can be polymerized.

  In addition, the photo-alignable polymerizable composition and the above-described composition can be produced while causing liquid crystal alignment ability in the layer (A) by irradiation with polarized light from the transparent substrate side or non-polarized light irradiation with respect to the substrate from an oblique direction. When the polymerizable liquid crystal composition is polymerized by active energy rays or heat, the polymerization reaction is performed while maintaining the light for aligning the photo-alignable group and fixing the alignment, so the photo-alignment operation and the polymerization operation are performed separately. Compared with the case, a photo-alignment film having excellent liquid crystal alignment ability and excellent alignment order can be obtained, and an optically anisotropic body having more excellent alignment can be obtained.

  Hereinafter, the present invention will be described more specifically with reference to examples.

(Preparation of a polymerizable liquid crystal composition containing a liquid crystal compound having a polymerizable group)
A liquid crystal composition comprising 20 parts by mass of the compound represented by the formula (a), 40 parts by mass of the compound represented by the formula (b), and 40 parts by mass of the compound represented by the formula (c) was prepared, and a polymerizable liquid crystal It was set as the composition (A-1).
The liquid crystal composition (A-1) had a CN transition temperature of 31 ° C. and an NI transition temperature of 48 ° C. When the temperature of the liquid crystal composition was lowered from 48 ° C., the liquid crystal composition was supercooled at 31 ° C. or lower and exhibited a liquid crystal phase even at 25 ° C.

A liquid crystal composition comprising 50 parts by mass of the compound represented by the formula (d) and 50 parts by mass of the compound represented by the formula (e) was prepared to obtain a polymerizable liquid crystal composition (A-2). The N-I transition temperature of the liquid crystal composition (A-2) was 74 ° C. When the temperature of the liquid crystal composition was lowered from 90 ° C., the liquid crystal composition became a nematic state at 71 ° C. or lower and exhibited a liquid crystal phase even at 25 ° C.
In addition, the polymerizable liquid crystal compositions (A-1) and (A-2) are diluted with xylene so that the solid content concentration becomes 50% by weight, and used with a filter having a pore diameter of 0.1 μm. Filtered.

(Preparation of photo-alignment polymerizable composition)
The compound represented by the formula (f) was dissolved in N-methylpyrrolidone to obtain a 1 wt% solid content solution. This solution was filtered through a filter having a pore size of 0.1 μm to obtain a photoalignable polymerizable composition solution (B).

Example 1
A TN type glass cell with an ITO electrode with a gap of 10 μm is made of two opposing glass substrates, and a polyimide alignment film whose rubbing directions are substantially orthogonal to each other is formed inside each substrate of the cell.
An ethanol solution (concentration 2 wt%) of a silane coupling agent 3-vinyltriethoxysilane was applied to both outer surfaces of the glass substrate of the cell and heat-treated at 110 ° C. for 10 minutes. Next, the photo-alignable polymerizable composition solution (B) was uniformly applied on the one-side substrate outside the cell with a spin coater, and dried with hot air at 80 ° C. for 10 minutes. In the plane of the substrate, the direction is perpendicular to the rubbing direction of the alignment film formed on the inner side of the substrate, and the output is about 45 nm from the ultrahigh pressure mercury lamp whose output is 1 KW from the direction inclined by 45 ° from the normal line of the coating film surface. Non-polarized light was irradiated with an integrated light amount of 5 J / cm ^{2 in} the state of parallel light, and liquid crystal alignment ability was imparted to the photo-alignable polymerizable composition layer.

Next, a photopolymerization initiator “Irgacure 907” manufactured by Ciba Specialty Chemicals was added to the polymerizable liquid crystal composition (A-1) so that the mass ratio was 98: 2. This was applied onto the photo-alignable polymerizable composition layer using an applicator at room temperature to form a polymerizable liquid crystal composition layer having a thickness of 6 μm. The cell is placed in a nitrogen atmosphere, and an ultra-high pressure mercury lamp is used to irradiate ultraviolet light having an intensity of 0.25 W / cm ² for 4 seconds from the same direction as the ultraviolet irradiation imparted with liquid crystal alignment ability. The polymerizable component in the composition layer and the polymerizable liquid crystal composition layer was polymerized to form an optical anisotropic body composed of a photo-alignment film layer and an anisotropic polymer layer.
Similarly, non-polarized light is irradiated to the outside of the other glass substrate of the cell from a direction orthogonal to the rubbing direction of the inner surface and inclined by 45 ° from the normal line of the substrate, and photo-alignment is performed in the same manner as above An optical anisotropic body composed of a film layer and an anisotropic polymer layer was formed.

Liquid crystal cell 11-3323 manufactured by Dainippon Ink & Chemicals, Inc. was poured into the glass cell to prepare liquid crystal cell 1.
The light intensity ratio of the backlight that passes through the glass cell with and without an AC electric field of 10V-30Hz is measured by changing the tilt angle from the normal of the cell surface along the rubbing direction. Dependency was measured. The viewing angle at which the contrast is 10 or more is shown in Table 1.
In addition, in order to evaluate the adhesive force between the photo-alignment film layer and the anisotropic polymer layer, the optically anisotropic body was cut into 2 mm square grids with a cutter, and serotape (cello tape is registered) Table 1 shows the ratio of the number of grids in which the optical anisotropic bodies remain. Since the photo-alignment film layer remained at the peeled portion by observation with a polarizing microscope, it was confirmed that the peeling occurred at the interface between the photo-alignment film layer and the anisotropic polymer layer. In addition, scratches and foreign matter were not observed on the surface and the inner surface of the optical anisotropic body, and the uniformity of retardation within the surface was good with a coefficient of variation of about 3%.

(Example 2)
To the photo-alignable polymerizable composition (B), 2,2′-azobis (2,4-dimethylvaleronitrile) “V65” manufactured by Wako Pure Chemical Industries, Ltd. was used as a thermal polymerization initiator. It added so that it might become weight%, it carried out similarly to Example 1, and it apply | coated uniformly on the one-side board | substrate of the cell outer side processed with the silane coupling agent, and dried with hot air for 30 minutes at 40 degreeC. Next, in the substrate plane, the direction is orthogonal to the rubbing direction of the alignment film formed on the inner side of the substrate, and the wavelength is around 365 nm from the ultrahigh pressure mercury lamp whose output is 1 kW from the direction inclined by 45 ° from the normal of the coating film surface. The non-polarized light was irradiated with an accumulated light amount of 5 J / cm ^{2 in} the state of parallel light, thereby imparting liquid crystal alignment ability to the photo-alignable polymerizable composition layer.

Next, 2,2′-azobis (2,4-dimethylvaleronitrile, W65 manufactured by Wako Pure Chemical Industries, Ltd.) as a thermal polymerization initiator was added to the polymerizable liquid crystal composition (A-2) at a mass ratio of 98: 2. It added so that it might become. This was applied onto the photo-alignable polymerizable composition layer at room temperature using an applicator to form a polymerizable liquid crystal composition layer having a thickness of 6 μm. The cell coated with the aligned polymerizable liquid crystal composition layer was heat-treated in nitrogen at 60 ° C. for 120 minutes to polymerize the polymerizable components in the photo-alignable polymerizable composition layer and the polymerizable liquid crystal composition layer. An optical anisotropic body composed of a photo-alignment film layer and an anisotropic polymer layer was formed. Similarly, an optical anisotropic body composed of a photo-alignment film layer and an anisotropic polymer layer oriented in a direction perpendicular to the rubbing direction of the inner surface was formed on the other glass surface of the cell.
Liquid crystal was injected in the same manner as in Example 1 to prepare a liquid crystal cell 2. Tests were conducted in the same manner as in Example 1, and the results are shown in Table 1.

(Example 3)
A polyimide rubbing alignment film was formed on the electrode of the glass substrate with ITO electrode, and a rubbing treatment was performed. After treating the surface of the substrate having no electrode with a silane coupling agent in the same manner as in Example 1, the photo-alignable polymerizable composition (B) was uniformly applied with a spin coater and the temperature was 15 at 80 ° C. It dried for minutes and obtained the photo-alignment polymeric composition layer. A photopolymerization initiator “Irgacure 907” manufactured by Ciba Specialty Chemicals was added to the polymerizable liquid crystal composition (A-1) so that the mass ratio was 98: 2. This was applied onto the photo-alignable polymerizable composition layer using an applicator at room temperature to form a polymerizable liquid crystal composition layer having a thickness of 6 μm. The substrate was placed in a nitrogen atmosphere, and the intensity was 0.25 W / cm ² using an ultrahigh pressure mercury lamp having an output of 1 KW from a direction perpendicular to the rubbing direction of the rubbing alignment film and inclined 45 ° from the normal line of the substrate. Non-polarized light having a wavelength of around 365 nm was irradiated in the state of parallel light for 20 seconds from the side opposite to the photo-alignable polymerizable composition layer with the substrate interposed therebetween. While producing the liquid crystal alignment ability in the photo-alignable polymerizable composition layer, the photo-alignable polymerizable composition layer and the aligned polymerizable liquid crystal composition are polymerized, and the photo-alignment film layer and the anisotropic weight are formed on the glass substrate. An optical anisotropic body composed of a combined layer was formed.

  Two substrates were prepared, and a TN cell was prepared by inserting a spacer into a sealing agent so that the rubbing alignment film of polyimide was inside, the rubbing direction was orthogonal, and the cell gap was 10 μm. Liquid crystal was injected in the same manner as in Example 1 to prepare a liquid crystal cell. Tests were conducted in the same manner as in Example 1, and the results are shown in Table 1.

Example 4
In Example 1, the amount of accumulated light in the state of collimated non-polarized light in the vicinity of a wavelength of 365 nm from a super-high pressure mercury lamp whose output is 1 KW from a direction inclined 45 ° from the normal line of the coating film surface to the photo-alignable polymerizable composition layer. After irradiating 5 J / cm ² and imparting liquid crystal alignment ability to the photo-alignable polymerizable composition layer, a photomask having a rectangular slit with a period of 20 μm is then placed on the photo-alignable polymerizable composition layer, Non-polarized light having a wavelength of about 365 nm using an ultrahigh pressure mercury lamp having an output of 1 kW from a direction perpendicular to the in-plane orientation direction of the photo-alignable polymerizable composition layer and inclined by 45 ° from the normal of the coating film surface. the irradiated integrated light quantity 5 J / cm ² in a state of parallel light, except that a rectangular alignment regions plane alignment direction is different by 90 ° photoaligning polymerizable composition layer gave orientation pattern alternating is performed Similar to Example 1, different from the photo-alignment film layer An optical anisotropic body composed of an isotropic polymer layer was prepared.

When a He—Ne laser (633 nm) passed through a polarizing plate is incident perpendicularly to the substrate surface and the polarization vibration direction is parallel to one orientation direction of the rectangular pattern, Raman-Nath scattering is exhibited. A diffraction peak up to ± 5th order was observed, confirming that it functions as a diffraction grating.
In addition, in order to evaluate the adhesive force between the photo-alignment film layer and the anisotropic polymer layer, the produced optical anisotropic body is cut into 2 mm square grids with a cutter, and serotape (cello tape is registered) (Trademark) was applied and pulled up in the vertical direction, and the ratio of the number of grids in which the optical anisotropic body remained was examined, and it was 87%. Since the photo-alignment film layer remained at the peeled portion by observation with a polarizing microscope, it was confirmed that the peeling occurred at the interface between the photo-alignment film layer and the anisotropic polymer layer.

(Comparative Example 1)
In the same manner as in Example 1, a phenol novolac epoxy acrylate having an acrylic group on the side chain of Dainippon Ink & Chemicals, Inc. on the outside of a TN type glass cell with an ITO electrode having a gap of 10 μm treated with a silane coupling agent NK ester EA-6310 new "ethyl cellosolve acetate solution (concentration: 30 wt%) was uniformly applied on one side substrate outside the cell with a spin coater and dried at 60 ° C for 30 minutes. By rubbing this, in-plane horizontal alignment ability was imparted. At that time, the orientation direction was set to be perpendicular to the orientation direction of the polyimide film inside the substrate. After rubbing treatment, a lot of dust of about 10 μm was adhered on the alignment film. Therefore, the surface was washed with running water to prevent deterioration of optical properties of the optical anisotropic body, rinsed with pure water, and rinsed at 70 ° C. for 30 minutes. Dried.

Next, a photopolymerization initiator “Irgacure 907” was added to the polymerizable liquid crystal composition (A-1) so as to have a mass ratio of 98: 2, and this was added to the rubbing-oriented phenol novolac acrylate layer at room temperature. Then, it was applied using an applicator to form a polymerizable liquid crystal composition layer having a thickness of 6 μm. Subsequently, the applied surface is irradiated with ultraviolet rays with an integrated light amount of ² J / cm ² from an ultra-high pressure mercury lamp with an output of 1 KW at room temperature in a nitrogen atmosphere, and a rubbing-oriented phenol novolac-type acrylate layer and an oriented polymerizable liquid crystal composition The material layer was polymerized to form an optical anisotropic body.
Similarly, an optical anisotropic body was formed on the other side of the cell. In the same manner as in Example 1, liquid crystal was injected to perform viewing angle measurement and cross-cut test. The results are shown in Table 1. When the optical anisotropic body was observed with a polarizing microscope, many scratches due to rubbing were observed along the alignment direction, and a decrease in optical uniformity was observed.

(Comparative Example 2)
In the same manner as in Example 1, on the outside of a TN type glass cell with an ITO electrode having a gap of 10 μm treated with a silane coupling agent, a photo-alignable polymerizable composition (B) and Wako Pure Chemical Industries, Ltd. as a thermal polymerization initiator were used. A composition having a mass ratio of 98: 2 with 2,2′-azobis (2,4-dimethylvaleronitrile “V65”) manufactured by the present invention was uniformly applied on one substrate on the outside of the cell and dried with hot air at 40 ° C. for 30 minutes. After that, from the ultrahigh pressure mercury lamp whose output is 1 kW from the direction which is orthogonal to the rubbing direction of the alignment film formed inside the substrate and inclined by 45 ° from the normal of the coating film surface. Non-polarized light in the vicinity of a wavelength of 365 nm was irradiated with an accumulated light amount of 5 J / cm ^{2 in} the state of parallel light, thereby imparting liquid crystal alignment ability to the photo-alignable polymerizable composition layer. Polymerized by heat treatment, orientation I was immobilized.

A photopolymerization initiator “Irgacure 907” is added to the polymerizable liquid crystal composition (A-1) on this alignment film so that the mass ratio is 98: 2, and the other composition is used at room temperature using an applicator. And a polymerizable liquid crystal composition layer having a thickness of 6 μm was formed. Subsequently, an ultraviolet ray with an integrated light amount of ² J / cm ² is irradiated onto the coated surface at a room temperature in a nitrogen atmosphere from an ultrahigh pressure mercury lamp having a power of 1 KW to polymerize the polymerizable liquid crystal, and the photo-alignment film layer and anisotropy An optical anisotropic body composed of a polymer layer was formed. Similarly, an optical anisotropic body composed of a photo-alignment film layer and an anisotropic polymer layer was formed on the other side of the cell.
In the same manner as in Example 1, liquid crystal was injected to perform viewing angle measurement and cross-cut test. The results are shown in Table 1. The optical anisotropic body was also observed with a polarizing microscope.

(Comparative Example 3)
In the same manner as in Example 1, on the outside of a TN type glass cell with an ITO electrode with a gap of 10 μm treated with a silane coupling agent, a phenol novolac type epoxy acrylate having a side chain with an acrylic group “NK ester EA-6310 new” and Ciba A toluene solution (concentration 5 wt%) of a composition in which a photopolymerization initiator “Irgacure 907” manufactured by Specialty Chemicals Co., Ltd. was mixed so as to have a mass ratio of 98: 2, was placed on one side substrate outside the cell using a spin coater. It was uniformly coated on top and dried at 60 ° C. for 30 minutes. Subsequently, in a nitrogen atmosphere, the coated surface was irradiated with an ultraviolet ray with an integrated light amount of ² J / cm ² from an ultrahigh pressure mercury lamp with an output of 1 KW and cured, and then this was rubbed to impart in-plane horizontal alignment ability. At that time, the orientation direction was set to be perpendicular to the orientation direction of the polyimide film inside the substrate. The surface was washed with running water, rinsed with pure water, and dried at 70 ° C. for 30 minutes.

Next, a composition having a mass ratio of 98: 2 between the polymerizable liquid crystal composition (A-1) and the photopolymerization initiator “Irgacure 907” was applied to the rubbing-oriented phenol novolac acrylate layer using an applicator. This was applied to form a polymerizable liquid crystal composition layer having a thickness of 6 μm. Subsequently, in a nitrogen atmosphere, the coated surface is irradiated with ultraviolet rays having an integrated light amount of ² J / cm ² from an ultrahigh pressure mercury lamp having an output of 1 KW, and is made of a rubbing-oriented phenol novolac acrylate layer and an anisotropic polymer layer. Anisotropic bodies were formed. Similarly, an optical anisotropic body composed of a phenol novolak acrylate layer and an anisotropic polymer layer that were rubbed and aligned was formed on the other side of the cell.
In the same manner as in Example 1, liquid crystal was injected to perform viewing angle measurement and cross-cut test. The results are shown in Table 1. The optical anisotropic body was also observed with a polarizing microscope.

  As a result, the optical anisotropic body obtained by the manufacturing methods of Examples 1 to 3 has no surface scratches and the like, has uniform and good orientation, and obtains a desired retardation. Therefore, a TN liquid crystal display element The effect of widening the viewing angle was excellent, and there was little interfacial peeling between the photo-alignment film layer and the polymerizable liquid crystal layer. In Comparative Example 1, since the surface of the alignment film was scratched, a decrease in optical uniformity was observed. Comparative Examples 2 and 3 were inferior in performance and interface peelability of the optical anisotropic body as an optical compensator.

  The optical anisotropic body obtained by the present invention has a birefringence such as a retardation film, a quarter-wave plate, a half-wave plate, an optical compensation film and the like used for a liquid crystal display device, and a polarization separation element. It can utilize for the optical function element which has.

In the present invention, the optical anisotropy obtained when the layer (A) is irradiated with polarized light or non-polarized light from an oblique direction through a photomask to produce liquid crystal alignment ability in two or more different directions in a pattern. It is the top view which showed the specific aspect of the body. In the present invention, the optical anisotropy obtained when the layer (A) is irradiated with polarized light or non-polarized light from an oblique direction through a photomask to produce liquid crystal alignment ability in two or more different directions in a pattern. It is the top view and side view which showed the specific aspect of the body.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Arrow which shows the orientation direction of the layer (B) in the same orientation area | region 2 Substrate 3 Layer (A) which produced liquid crystal orientation ability in the direction of two or more different directions in pattern form
4 layers (B)

Claims (11)

A liquid crystal composition having a polymerizable group in which a laminated film of a photo-alignable polymerizable composition layer (A) and a polymerizable liquid crystal composition layer (B) that generates liquid crystal aligning ability upon light irradiation is formed on a substrate. A method for producing an optical anisotropic body, wherein both layers are polymerized in a state in which the is oriented. Forming a photo-alignable polymerizable composition layer (A) on which a liquid crystal alignment ability is generated by light irradiation on a substrate, polarized light irradiation or from the surface side of the substrate or the photo-alignable polymerizable composition layer (A) After the non-polarized light irradiation from the oblique direction is performed on the substrate, the photo-alignable polymerizable composition layer (A) is caused to have liquid crystal alignment ability, and then the polymerizable liquid crystal composition layer (B The method for producing an optical anisotropic body according to claim 1, wherein both layers are polymerized. On the substrate, a photo-alignable polymerizable composition layer (A) in which liquid crystal alignment ability is generated by light irradiation, and after forming the polymerizable liquid crystal composition layer (B) on the layer, the substrate side or the From the surface side of the polymerizable liquid crystal composition layer (B), the photo-alignment polymerizable composition layer (A) has a liquid crystal alignment ability by irradiating polarized light or non-polarized light from an oblique direction with respect to the substrate. The method for producing an optical anisotropic body according to claim 1, wherein both layers are polymerized while or after being generated. 4. The optical anisotropic body according to claim 2, wherein the substrate is a transparent substrate, and the liquid crystal alignment ability is generated by irradiation with polarized light from the transparent substrate side or non-polarized light irradiation from an oblique direction to the substrate. Production method. The photo-alignable polymerizable composition layer (A) that generates liquid crystal alignment ability by light irradiation has a photo-alignment group that exhibits liquid crystal alignment ability by photo-isomerization reaction, photo-dimerization reaction, or photo-crosslinking reaction in one molecule. And a compound (C) having at least one polymerizable group, and a method for producing an optical anisotropic body according to claim 1. 6. The method for producing an optical anisotropic body according to claim 5, wherein the photo-alignment group is an azobenzene group, an anthraquinone group, a benzophenone group, a cinnamoyl group, a chalcone group or a coumarin group. The method for producing an optical anisotropic body according to claim 5 or 6, wherein the compound (C) is a compound represented by the general formula (1).

(In the formula, R ¹ and R ² are each independently selected from the group consisting of (meth) acryloyl group, (meth) acryloyloxy group, (meth) acrylamide group, vinyl group, vinyloxy group, and maleimide group). Represents a polymerizable group.
X ¹ represents a linking group represented by — (A ¹ -B ¹ ) _m —, and X ² represents a linking group represented by — (B ² -A ² ) _n —. Here, A ¹ and A ² each independently represent a single bond or a divalent hydrocarbon group, and B ¹ and B ² each independently represent a single bond, —O—, —CO—O—, — OCO-, -CONH-, -NHCO-, -NHCO-O-, or -OCONH- is represented. m and n each independently represents an integer of 0 to 4. When m or n is 2 or more, a plurality of A ¹ , B ¹ , A ² and B ² may be the same or different. However, A ¹ or A ² sandwiched between two B ¹ or two B ² is not a single bond.
Y represents a group having an azobenzene group, an anthraquinone group, a benzophenone group, a cinnamoyl group, a chalcone group or a coumarin group. ) In the said General formula (1), Y is group represented by the following structure, The manufacturing method of the optical anisotropic body of Claim 7.

(Wherein p _{1 to} p ₁₁ are each independently a hydrogen atom, a halogen atom, a halogenated alkyl group, a halogenated alkoxy group, a cyano group, a nitro group, an alkyl group, an alkoxy group, an aryl group, an allyloxy group, an alkoxy group. Represents a carbonyl group, a carboxyl group, a sulfonic acid group, an amino group, or a hydroxy group, provided that the carboxyl group and the sulfonic acid group may form a salt with an alkali metal. The optically anisotropic body according to any one of claims 1 to 8, wherein the polymerizable liquid crystal composition layer (B) contains a rod-like liquid crystal compound having a polymerizable group or a discotic liquid crystal compound having a polymerizable group. Production method. The method for producing an optical anisotropic body according to claim 1, wherein the substrate is a glass substrate or a plastic substrate. The liquid crystal alignment ability is produced in two or more different directions in a pattern by irradiating the photo-alignable polymerizable composition layer (A) with polarized light or non-polarized light from an oblique direction through a photomask. The manufacturing method of an optical anisotropic body in any one of 1-10.

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