JP2015049419A - Composition for optical orientation film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal orientation film that has high optical orientation sensitivity after high temperature firing, has excellent adhesion to an undercoat, is soluble in an alcoholic solvent, and can be manufactured at a low cost; and a composition for an optical orientation film for forming the same.SOLUTION: There is provided a composition for an optical orientation film that contains: a compound (A1) obtained by reacting at least one acid anhydride (a1) selected from the group of compounds represented by the formulas (1) and (2) with a compound (a2) having amino and alkoxysilyl in molecules, or a polymer (A2) obtained by polymerizing the compound (A1); and an organic solvent (B). In the formulas, R, R, and Reach independently are hydrogen or an alkyl having a carbon number of 1 to 5.

Description

The present invention relates to a composition for a photoalignment film, a photoalignment film formed using the composition, and an optical film or a liquid crystal display device using the composition.

Liquid crystal display elements are used in various liquid crystal display devices such as monitors for notebook computers and desktop computers, as well as video camera viewfinders, projection displays, and televisions. Furthermore, it is also used as an optoelectronic-related element such as an optical printer head, an optical Fourier transform element, or a light valve. As a conventional liquid crystal display element, a display element using nematic liquid crystal is mainly used, and the alignment direction of the liquid crystal in the vicinity of one substrate and the alignment direction of the liquid crystal in the vicinity of the other substrate are twisted at an angle of 90 °. TN (Twisted Nematic) mode, STN (Super Twisted Nematic) mode in which the orientation direction is twisted at an angle of usually 180 ° or more, IPS (In Plane Switching) in which the orientation direction is oriented horizontally with respect to the substrate, Liquid crystal display elements such as FFS (Fringe Field Switching) mode have been put into practical use.

However, these liquid crystal display elements have a narrow viewing angle for properly recognizing an image, and when viewed from an oblique direction, luminance and contrast may be reduced, and luminance inversion may occur in a halftone. In recent years, this viewing angle problem has been caused by a TN type liquid crystal display element using an optical compensation film, an MVA (Multi-domain Vertical Alignment) mode using a technique of vertical alignment and a protruding structure (see Patent Document 1). Alternatively, it is improved by a lateral electric field type IPS (In-Plane Switching) mode (see Patent Document 2).

The development of the technology of the liquid crystal display element is achieved not only by simply improving these driving methods and element structures but also by improving members used for the display element. Among the members used for display elements, the liquid crystal alignment film is one of the important elements related to the display quality of the liquid crystal display element, and the role of the liquid crystal alignment film is important year by year as the quality of the display element increases. It is becoming.

The liquid crystal alignment film needs to uniformly control the molecular arrangement of the liquid crystal for the uniform display characteristics of the liquid crystal display element. Therefore, it is required to uniformly align the liquid crystal molecules on the substrate in one direction.

Further, in order to realize an improvement in contrast of an image display device and an expansion of a viewing angle range, for example, a stretched film having refractive index anisotropy or a polymerizable liquid crystalline compound is aligned as an optical compensation film or a retardation film. Thereafter, a film obtained by polymerizing a compound is used. A liquid crystal alignment film is also used for aligning the polymerizable liquid crystal compound. A liquid crystal alignment film that uniformly aligns the directions of liquid crystal molecules on a substrate is used in various scenes in the manufacturing process of a liquid crystal display element, and the technology is important and indispensable.

The liquid crystal alignment film is prepared using a liquid crystal alignment agent. Currently, the liquid crystal aligning agent mainly used is a solution in which polyamic acid or soluble polyimide is dissolved in an organic solvent. After applying such a solution to a substrate, a polyimide-based liquid crystal alignment film is formed by film formation by means such as heating. Various liquid crystal aligning agents other than polyamic acid are also being studied, but they are almost practical in terms of heat resistance, chemical resistance (liquid crystal resistance), coating properties, liquid crystal alignment properties, electrical properties, optical properties, display properties, etc. It has not reached.

Industrially, a rubbing method that is simple and capable of high-speed processing of a large area is widely used as an alignment processing method. The rubbing method is a process of rubbing the surface of the liquid crystal alignment film in one direction using a cloth in which fibers of nylon, rayon, polyester, or the like are planted, and this makes it possible to obtain uniform alignment of liquid crystal molecules. However, the rubbing method generates a lot of dust and static electricity, and there is a concern about the influence on the liquid crystal element due to alignment defects.

Therefore, in recent years, a liquid crystal alignment control method has been developed in place of the rubbing method. As for the photo-alignment method in which alignment treatment is performed by irradiating light, many alignment methods such as a photolysis method, a photoisomerization method, a photodimerization method, and a photocrosslinking method have been proposed (Non-patent Documents 1 and 3). And Patent Document 4). Unlike the rubbing method, the photo-alignment method is a non-contact alignment method, and in principle, dust generation and static electricity are less generated than the rubbing treatment.

The alignment state of the liquid crystal monolayer in contact with the liquid crystal alignment film can be controlled by using a liquid crystal alignment film that has been aligned by the photo-alignment method and has good alignment properties, and alignment division is easy It becomes possible. Thus, it can be expected to improve the performance as a liquid crystal display element.

As a compound that can be used in the photo-alignment method, a polymer in which a photoreactive cinnamate is bonded to a side chain of a copolymer has been proposed (see Patent Documents 5 and 6). However, in this system, the liquid crystal alignment ability often deteriorates when baked at a high temperature, and there are cases where there is a problem in base adhesion. Further, a solvent having a high dissolving power is required for the solvent for dissolving these polymers, and in particular, in the case of a flexible plastic base material, it has been difficult to use because the base material is eroded. On the other hand, there is also a problem that the cost is increased because polymerization is performed after synthesizing a monomer having a special structure.

On the other hand, a siloxane compound having a maleimide structure has been proposed as a photocurable composition (see Patent Document 7). However, Patent Document 7 does not mention anything about the photo-alignment of the liquid crystal compound.

Japanese Patent No. 2947350 Japanese Patent No. 2940354 JP 2005-275364 A Japanese Patent Laid-Open No. 11-15001 Patent No. 3611342 Patent No. 4011652 Japanese Patent No. 2630596

Liquid Crystal Vol. 3 No. 4, edited by the Japanese Liquid Crystal Society Editorial Board, published by the Japanese Liquid Crystal Society, 1999, page 262

An object of the present invention is to provide a composition for a photoalignment film suitable for the photoalignment method. Specifically, it provides a liquid crystal alignment film that has high photo-alignment sensitivity after high-temperature firing, excellent adhesion to the substrate, is soluble in alcoholic solvents (does not erode flexible substrates), and can be manufactured at low cost. It is to be.

As a result of diligent research and development, the present inventor has realized a liquid crystal alignment film that can achieve the above object by using a specific composition for photo-alignment film.

式中、Ｒ^１、Ｒ^２およびＲ^３はそれぞれ独立して、水素または炭素数１〜５のアルキルである。 The present invention includes the following items.
[1] A reaction of at least one acid anhydride (a1) selected from the group of compounds represented by formulas (1) and (2) with a compound (a2) having amino and alkoxysilyl in the molecule. The composition for photo-alignment films containing the polymer (A2) obtained by polymerizing the compound (A1) or the compound (A1) obtained in this way, and the organic solvent (B).

In formula, R < ¹ >, R < ² > and R < ³ > are respectively independently hydrogen or a C1-C5 alkyl.

[2] The composition for photoalignment film according to the item [1], wherein the acid anhydride (a1) is at least one selected from maleic anhydride, itaconic anhydride and citraconic anhydride.

[3] The compound (a2) having amino and alkoxysilyl in the molecule is 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 4-aminophenyltrimethoxysilane, and 4-aminophenyltriethoxysilane. The composition for photo-alignment films according to the item [1] or [2], which is at least one selected from:

[4] A photo-alignment film prepared by using the photocurable composition described in any one of [1] to [3].

[5] A display device manufactured using the photo-alignment film according to the item [4].

In the present invention, since a liquid crystal alignment film is formed using a compound having a photoreactive group, complicated processing steps found in the conventional rubbing treatment can be omitted, and due to dust generation and static electricity generated at that time. Alignment defects do not occur. Therefore, a liquid crystal alignment film with high optical uniformity can be created. In addition, an optical film and a liquid crystal display element manufactured using the liquid crystal alignment film can maintain high alignment stability.

The composition for photo-alignment films of the present invention comprises at least one acid anhydride (a1) selected from the group of compounds represented by the following formulas (1) and (2), amino and alkoxysilyl in the molecule. The compound (A1) obtained by making it react with the compound (a2) which has it, or the polymer (A2) obtained by polymerizing the compound (A1), and the organic solvent (B) which melt | dissolves it are included. Specifically, the compound (A1) is a silane coupling agent having a photopolymerizable group (maleimide, citraconimide, itaconimide) obtained by reacting the acid anhydride (a1) and the compound (a2). Specifically, the polymer (A2) is a siloxane polymer having a polymerizable group (maleimide, citraconimide, itaconimide) obtained by polycondensation of the compound (A1). Hereinafter, the compound, polymer, solvent, and other elements constituting the present invention will be described.

式中、Ｒ^１、Ｒ^２およびＲ^３はそれぞれ独立して、水素、炭素数１〜５のアルキルである。 1. Acid anhydride (a1)
The acid anhydride (a1) is at least one selected from the group of compounds represented by the following formulas (1) and (2).

In formula, R < ¹ >, R < ² > and R < ³ > are respectively independently hydrogen and a C1-C5 alkyl.

Specific examples of the acid anhydride (a1) are maleic anhydride, itaconic anhydride, citraconic anhydride, and 2,3-dimethylmaleic anhydride. The acid anhydride (a1) may be used alone or in combination of two or more.

2. Compound having amino and alkoxysilyl in the molecule (a2)
Specific examples of the compound (a2) having amino and alkoxysilyl in the molecule include 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyldimethoxymethylsilane, and 3-aminopropyldiethoxymethylsilane. 4-aminophenyltrimethoxysilane, 4-aminophenyltriethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, and N-2- (aminoethyl) -3-aminopropyltriethoxy Silane. More preferred compounds (a2) are 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyldimethoxymethylsilane, and 3-aminopropyldiethoxymethylsilane, and more preferred compound (a2) Are 3-aminopropyltrimethoxysilane and 3-aminopropyltriethoxysilane.

3. Compound (A1)
The acid anhydride (a1) and the compound (a2) are easily reacted by stirring in a solvent at room temperature to produce an amic acid. Thereafter, the amic acid is heated to imidize to obtain the compound (A1). The heating temperature when imidizing is 60 to 150 ° C, preferably 80 to 130 ° C. A base catalyst may be added as an imidation catalyst. Examples of base catalysts are pyridine, triethylamine, trimethylamine, tributylamine, and trioctylamine. Moreover, a polymerization inhibitor can also be used together for the purpose of suppressing the polymerization of the photopolymerizable group induced during this reaction. Examples of polymerization inhibitors are 2,2,6,6-tetramethylpiperidinyl-1-oxyl, 4-hydroxy-2,2,6,6-tetramethylpiperidinyl-1-oxyl, triphenyldazyl , P-methoxyphenol, and hydroquinone.

The solvent used for the reaction for synthesizing the compound (A1) is not particularly limited as long as it can dissolve the raw acid anhydride (a1), the compound (a2) and the compound (A1) obtained by the reaction. However, when it is necessary to suppress the hydrolysis and condensation of the alkoxysilyl moiety of the compound (A1), it is preferable to synthesize at a low concentration and a low temperature using a solvent having a hydroxyl group. By making heating temperature 60-60 degreeC, the production | generation of the polymer by reaction of an alkoxy silyl site | part can be suppressed, and a compound (A1) can be obtained with a high yield.

4). Polymer (A2)
The obtained compound (A1) may be used as it is in the composition for a photoalignment film of the present invention, but it is more preferable to use it as a polymer because a uniform photoalignment film can be easily obtained by various coating methods. In order to obtain the polymer (A2) by polymerizing the compound (A1), hydrolysis condensation of the alkoxysilyl moiety is necessary. The polymer (A2) can be obtained by adding the acid catalyst such as water and formic acid to the compound (A1) and further heating to distill off the low boiling point. The heating temperature during this reaction is preferably 90 to 150 ° C.

Further, when the compound (A1) is synthesized and heated at a high concentration / high temperature, the amidic acid generated in the first reaction itself serves as an acid catalyst, and the alkoxysilyl group is formed by water generated by imidization of the amic acid. In order to induce the hydrolysis reaction, the polymer (A2) can be obtained in one step. The heating temperature during this reaction is preferably 100 to 150 ° C.

The solvent used for the polymerization reaction is not particularly limited as long as it can dissolve the polymer (A2). When formic acid and water are added as a catalyst, the hydrolysis condensation reaction can be further advanced.

The polymer (A2) is a siloxane polymer having a photopolymerizable group, and its weight average molecular weight is in the range of 500 to 1,000,000. The weight average molecular weight is preferably 1,000 to 500,000, and more preferably 2,000 to 100,000 from the viewpoints of easy filtration, storage stability, and photoalignment ability.

5. Organic solvent (B)
The organic solvent (B) is an organic solvent that can dissolve the acid anhydride (a1) and the compound (a2), and can dissolve the compound (A) obtained by reacting (a1) and (a2). When the photo-alignment film is formed by spin coating, slit coating, or other printing methods, an organic solvent having high coating uniformity is preferable. When the base is a flexible substrate, it is preferable to use an alcohol solvent in order to avoid erosion of the substrate.

Examples of the organic solvent include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, isobutyl alcohol, tert-butyl alcohol, acetone, 2-butanone, ethyl acetate, propyl acetate, tetrahydrofuran, acetonitrile. , Dioxane, toluene, xylene, cyclopentanone, cyclohexanone, diacetone alcohol, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether, diethylene glycol dimethyl ether, diethylene glycol methyl ethyl Ether, methyl 3-methoxypropionate, and - ethyl ethoxypropionate, N- methylpyrrolidone, γ- butyrolactone.

From the viewpoint of coating properties, storage stability, and avoiding erosion of the base, an organic solvent having a hydroxyl group is more preferable. Specific examples thereof include ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, isobutyl alcohol, tert-butyl alcohol, diacetone alcohol, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, propylene glycol monomethyl ether. Diethylene glycol monoethyl ether. Among these, propylene glycol monomethyl ether and diacetone alcohol having an appropriate boiling point are more preferable.

6). Other components The composition for photo-alignment films of the present invention further contains other components than the compound (A1), the polymer (A2) and the organic solvent (B) described above within the range in which the effects of the present invention are obtained. You may do it. For example, various additives can be added to the composition for photo-alignment films of the present invention in order to improve coating uniformity, film hardness, and adhesion. Examples of such additives include acrylic, styrene, polyethyleneimine, or urethane polymer dispersants, anionic, cationic, nonionic, or fluorine surfactants, and improved silicone coating properties. Agents, hindered phenols, hindered amines, phosphorus, sulfur compounds and other antioxidants, coupling agents and other adhesion improvers, epoxy compounds and other thermal crosslinking agents, photoradical initiators, thermal radical initiators, etc. These radical generators or sensitizers.

6-1. Polymer dispersing agent, surfactant, coatability improver The polymer dispersing agent, surfactant, and coatability improving agent may be components used for these applications in the composition. These may be one type or two or more types. Examples of such a polymer dispersant, surfactant, and coatability improver include, for example, Polyflow No. 45, polyflow KL-245, polyflow no. 75, Polyflow No. 90, polyflow no. 95 (all are trade names, manufactured by Kyoeisha Chemical Industry Co., Ltd.), Disperbak 161, Disper Bake 162, Disper Bake 163, Disper Bake 164, Disper Bake 166, Disper Bake 170, Disper Bake 180, Disper Bake 181, Disper Bake 182, BYK300, BYK306, BYK310, BYK320, BYK330, BYK342, BYK344, BYK346, BYK361N (all are trade names, manufactured by BYK Japan KK), KP-341, KP-358, KP -368, KF-96-50CS, KF-50-100CS (all are trade names, manufactured by Shin-Etsu Chemical Co., Ltd.), Surflon SC-101, Surflon KH-40 (above, Izu) Product name, manufactured by Seimi Chemical Co., Ltd.), Footent 222F, Footgent 251, FTX-218 (all of which are trade names, manufactured by Neos Co., Ltd.), EFTOP EF-351, EFTOP EF-352, EFTOP EF -601, EFTOP EF-801, EFTOP EF-802 (all are trade names, manufactured by Mitsubishi Materials Corporation), MegaFuck F-171, MegaFuck F-177, MegaFuck F-475, MegaFuck R- 08, MegaFac R-30 (all are trade names, manufactured by DIC Corporation), fluoroalkylbenzene sulfonate, fluoroalkylcarboxylate, fluoroalkylpolyoxyethylene ether, fluoroalkylammonium iodide, fluoroalkyl Betaine, fluoroalkyl sulfone Acid salt, diglycerin tetrakis (fluoroalkylpolyoxyethylene ether), fluoroalkyltrimethylammonium salt, fluoroalkylaminosulfonate, polyoxyethylene nonylphenyl ether, polyoxyethylene octylphenyl ether, polyoxyethylene alkyl ether, polyoxy Ethylene lauryl ether, polyoxyethylene oleyl ether, polyoxyethylene tridecyl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene laurate, polyoxyethylene oleate, polyoxyethylene stearate, polyoxyethylene Laurylamine, sorbitan laurate, sorbitan palmitate, sorbitan stearate, sorbitan Acid, sorbitan fatty acid ester, polyoxyethylene sorbitan laurate, polyoxyethylene sorbitan palmitate, polyoxyethylene sorbitan stearate, polyoxyethylene sorbitan oleate, polyoxyethylene naphthyl ether, alkyl benzene sulfonate, and alkyl diphenyl ether disulfonic acid Salt.

Among these, fluoroalkyl benzene sulfonate, fluoroalkyl carboxylate, fluoroalkyl polyoxyethylene ether, fluoroalkyl ammonium iodide, fluoroalkyl betaine, fluoroalkyl sulfonate, diglycerin tetrakis (fluoroalkyl polyoxyethylene ether) ), Fluorosurfactants such as fluoroalkyltrimethylammonium salts, and fluoroalkylaminosulfonates, and silicon systems such as BYK306, BYK342, BYK344, BYK346, KP-341, KP-358, and KP-368 It is preferable that at least one selected from the group consisting of coatability improvers is included in the additive from the viewpoint of enhancing the coating uniformity of the composition for photo-alignment films of the present invention.

The content of the polymer dispersant, the surfactant, and the coatability improver in the composition for photo-alignment film of the present invention is 0.001 to 0 based on 100 parts by weight of the total solid content of the composition, respectively. .1 part by weight is preferred.

6-2. Antioxidant Antioxidants of hindered phenol-based, hindered amine-based, phosphorus-based and sulfur-based compounds can be suitably used as the antioxidant. One type or two or more types of antioxidants may be used. The antioxidant is preferably an antioxidant of a hindered phenol compound from the viewpoint of weather resistance. The antioxidant, e.g. Irganox1010, IrganoxFF, Irganox1035, Irganox1035FF, Irganox1076, Irganox1076FD, Irganox1076DWJ, Irganox1098, Irganox1135, Irganox1330, Irganox1726, Irganox1425 WL, Irganox1520L, Irganox245, Irganox245FF, Irganox245DWJ, Irganox259, Irganox3114, Irganox565, Irganox565DD Irganox 295 (all are trade names; manufactured by BASF Japan Ltd.), ADK STAB AO-20, ADK STAB AO-30, AD STAB AO-50, ADK STAB AO-60, ADK STAB AO-70, and ADK STAB AO-80 (trade names; Co. ADEKA) and the like. Among these, ADK STAB AO-60 is more preferable.

The content of the antioxidant in the composition for photo-alignment films of the present invention is preferably 0.1 to 5 parts by weight and 100 to 3 parts by weight with respect to 100 parts by weight of the compound (A). Is more preferable.

6-3. Adhesion improver The adhesion improver is used to improve the adhesion between the photoalignment film composition and the substrate. A coupling agent can be suitably used as the adhesion improver. The adhesion improver may be one type or two or more types. As the coupling agent, a silane-based, aluminum-based or titanate-based compound can be used. Examples of such coupling agents include 3-glycidoxypropyldimethylethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltrimethoxysilane, acetoalkoxyaluminum diisopropylate, and tetra And isopropyl bis (dioctyl phosphite) titanate. Among these, 3-glycidoxypropyltrimethoxysilane is preferable because of its great effect of improving adhesion.

The content of the adhesion improver in the composition for photo-alignment films of the present invention is preferably 10 parts by weight or less with respect to 100 parts by weight of the compound (A).

6-4. Thermal crosslinking agent The thermal crosslinking agent may be a component that causes a crosslinking reaction under heating conditions in film formation using the composition for photo-alignment films. One or more thermal crosslinking agents may be used. A thermal crosslinking agent such as an epoxy compound can be used as the thermal crosslinking agent. Examples of such a thermal crosslinking agent include Epicoat 807, Epicoat 815, Epicoat 825, Epicoat 827, Epicoat 828, Epicoat 190P, Epicoat 191P, and Epicoat. 1004, Epicoat 1256, YX8000 (all are trade names; manufactured by Japan Epoxy Resin Co., Ltd.), Araldite CY177, Araldite CY184 (all are trade names: manufactured by BASF Japan), Celoxide 2021P, EHPE-3150 (All are trade names; manufactured by Daicel Chemical Industries, Ltd.) and Techmore VG3101L (trade names; manufactured by Printec Co., Ltd.)).

The content of the thermal crosslinking agent in the composition for photo-alignment films of the present invention is preferably 1 to 30 parts by weight and more preferably 5 to 15 parts by weight with respect to 100 parts by weight of the solid content of the composition. preferable.

6-5. Radical generators / sensitizers Photoradical generators include 2-hydroxy-2-methyl-1-phenylpropan-1-one (DAROCUR1173), 1-hydroxycyclohexyl phenyl ketone, 2,2-dimethoxy-1,2 -Diphenylethane-1-one (IRGACURE 651), 1-hydroxy-cyclohexyl-phenyl-ketone (IRGACURE 184), IRGACURE 127, IRGACURE 500 (mixture of IRGACURE 184 and benzophenone), IRGACURE 2959, IRGACURE 759, IRGACURE 759, IRGACURE 369 , IRGACURE 1800, IRGACU E1850, IRGACURE1870, DAROCUR4265, DAROCUR MBF, DAROCUR TPO, IRGACURE784, IRGACURE754, IRGACURE OXE01, and IRGACURE OXE02 the like. Both DAROCUR and IRGACURE are trade names of BASF Japan. These are known sensitizers (isopropylthioxanthone, diethylthioxanthone, ethyl-4 dimethylaminobenzoate (DAROCUR EDB), 2-ethylhexyl-4-dimethylaminobenzoate (DAROCUR EHA), 4,4′-dimethylaminobenzophenone (Nippon Soda) Nisocure MABP manufactured by Co., Ltd.) and 4,4′-diethylaminobenzophenone (dialkylaminobenzophenone such as EAB manufactured by Hodogaya Chemical Co., Ltd.) may be added.

Examples of the thermal radical generator include 2,2′-Azobis (4-methoxy-2,4-dimethylvaleronitrile) (V-70 manufactured by Wako Pure Chemical Industries, Ltd.), 2,2′-Azobis (2,4-dimethylvaleronitile). ) (V-65 manufactured by Wako Pure Chemical Industries, Ltd.), 2,2′-Azobis (isobutyronitrile) (V-60 manufactured by Wako Pure Chemical Industries, Ltd.), 2,2′-Azobis (2-methylbutyronitrile) ( V-59) manufactured by Wako Pure Chemical Industries, Ltd., 2,2′-Azobis [N- (2-propenyl) -2-methylpropionamide] (VF-096 manufactured by Wako Pure Chemical Industries, Ltd.), 2, 2 ′ -Azobis (N-butyl-2-methylpropiona ide) (manufactured by Wako Pure Chemical Industries, Ltd. VAm-110), include Dimethyl 2,2'-azobis (isobutyrate) (manufactured by Wako Pure Chemical Industries, Ltd. V-601).

The content of the radical initiator / sensitizer in the composition for photoalignment film of the present invention is preferably 0.1 to 10 parts by weight with respect to 100 parts by weight of the solid content of the composition. Part is more preferable, and 3 to 10 is more preferable.

7). Storage conditions for composition for photo-alignment film The composition for photo-alignment film of the present invention can be stored while being shielded from light in the temperature range of -30 ° C to 25 ° C. To preferred. A storage temperature of −20 ° C. to 10 ° C. is even more preferable from the viewpoint of preventing the generation of precipitates from the photosensitive composition.

8). Deposition of Photo Alignment Film and Evaluation of Alignment of Polymerizable Liquid Crystal Hereinafter, a method of forming a photo alignment film and an evaluation of alignment using a polymerizable liquid crystal as a material to be aligned on the photo alignment film will be described.

8-1. Film-forming method of photo-alignment film The composition for photo-alignment film of the present invention is applied on a substrate by a known method such as spin coating, roll coating, slit coating or the like. As the substrate, for example, transparent glass substrate such as white plate glass, blue plate glass, silica coated blue plate glass, synthetic resin sheet such as polycarbonate, polyethersulfone, polyester, acrylic, vinyl chloride, aromatic polyamide, polyamideimide, polyimide, Examples of the semiconductor substrate include a film or substrate, a metal substrate such as an aluminum plate, a copper plate, a nickel plate, and a stainless plate, other ceramic plates, and a photoelectric conversion element. These substrates may be subjected to a pretreatment such as a chemical treatment such as a silane coupling agent, plasma treatment, ion plating, sputtering, a gas phase reaction method, or vacuum deposition.

Next, the coating film of the composition for photo-alignment films on a board | substrate is dried with a hotplate or oven. Usually, it is dried at 60 to 150 ° C. for 1 to 5 minutes. The film thickness of the photo-alignment film is not particularly limited, but is generally formed to a film thickness of about 1 nm to 300 nm. The photo-alignment film on the dried substrate is irradiated with light irradiated from a light irradiation device such as an ultra-high pressure mercury lamp converted into polarized light by a polarizing plate such as a wire grid. The irradiation amount is suitably about 1 to 3000 mJ / cm ² at a wavelength of 300 to 450 nm.

8-2. Method for evaluating orientation of polymerizable liquid crystal First, a polymerizable liquid crystal composition used for evaluation was prepared as follows. LC242 (trade name, manufactured by BASF Japan) 5.0g, IRGACURE907 (trade name, manufactured by BASF Japan) 0.25g, BYK361N (trade name, manufactured by Big Chemie Japan) 0. 0050 g, and toluene as an organic solvent is further added so that the organic solvent becomes 85 wt% of the whole, and uniformly mixed and dissolved. This composition is referred to as “polymerizable liquid crystal composition (1)”.

8-2-1. Polymerization liquid crystal composition (1) is formed by a coating method such as spin coating on a substrate with a photo-alignment film irradiated with pre-bake photo-alignment sensitivity polarized light, and dried at 80 ° C. for 1 minute on a hot plate. To do. After the substrate is cooled to room temperature, the entire alignment line is irradiated by irradiating all lines such as an ultra-high pressure mercury lamp, and the alignment is fixed by photocuring the polymerizable liquid crystal composition. The prepared polymerizable liquid crystal photocured substrate is sandwiched between two polarizing plates in an orthogonal (crossed Nicols) state, and the backlight is irradiated from below and observed. If the polymerizable liquid crystal is horizontally aligned, bright and dark states are alternately observed when the substrate is rotated. The minimum exposure amount at which bright and dark display was possible without alignment defects (light loss) was defined as “photo alignment sensitivity after pre-bake”.

8-2-2. Post-bake post photo-alignment sensitivity As described above, a photo-alignment film is spin-coated on a glass substrate, dried at 130 ° C. for 5 minutes, and further post-baked at 230 ° C. for 30 minutes. Thereafter, the light irradiated from the ultra-high pressure mercury lamp is converted into linearly polarized light through a filter that cuts light of 300 nm or less and a wire grid polarizing plate, and 10 mJ / cm ² (value at 313 nm is applied to the glass substrate on which the photo-alignment film is applied. ) Irradiate. Next, the polymerizable liquid crystal composition (1) is spin-coated on the substrate at a rotation speed of 1300 rpm for 10 seconds, and dried on a hot plate at 80 ° C. for 1 minute. After cooling the substrate to room temperature, the entire line of the ultra-high pressure mercury lamp is irradiated with 300 mJ / cm ² (value at 313 nm) to photocur the polymerizable liquid crystal composition and fix the alignment. The prepared polymerizable liquid crystal photocured substrate is sandwiched between two polarizing plates in an orthogonal (crossed Nicols) state, and the backlight is irradiated from below and observed. If the polymerizable liquid crystal is horizontally aligned, bright and dark states are alternately observed when the substrate is rotated. The minimum exposure amount at which bright and dark display was possible without alignment defects (light loss) was defined as “post-bake post-bake photo-alignment sensitivity”.

8-3. Evaluation Method of Substrate Adhesion A cross-cut test is performed using the substrate after immobilization of the polymerizable liquid crystal prepared by the evaluation of the photoalignment sensitivity. Using a cutter and a cross-cut guide, a 1-mm square 100-mass cut is created, and adhesiveness is evaluated by applying an adhesive tape and peeling it from the top. The case where peeling did not occur in all of the 100 squares after the tape was peeled was rated as ◎, the case where peeling did not occur in 80% or more was marked as ◯, and the case where it was less than x. The test was performed on both the substrate after the pre-bake post-bright photosensitivity test and the substrate after the post-bake photo-alignment sensitivity test.

EXAMPLES Hereinafter, although an Example demonstrates this invention more concretely, this invention is not restrict | limited by these Examples.

[Synthesis Example 1] Synthesis of Compound (A1) A four-necked flask with a stirrer is propylene glycol monomethyl ether as a polymerization solvent, maleic anhydride as a compound (a1), 3-aminopropyltriethoxysilane as a compound (a2), polymerization Dibutylhydroxytoluene as an inhibitor was charged in the following weight. The four-necked flask was heated in an oil bath set at 100 ° C. for 1 hour, and further set at 120 ° C. and aged for 2 hours.

The concentrated reaction liquid was cooled to room temperature and then recovered to obtain a compound (A1) solution having a solid content concentration of 40 wt%. Here, the solid content concentration was determined by a dry weight method. The measuring method is as follows. A small amount of the compound (A1) solution is applied to a 40 × 40 mm square glass substrate with a bar coater, and the initial weight W1 is measured. Thereafter, the glass substrate is dried on a hot plate at 100 ° C. for 5 minutes, and the weight W2 is measured again. Finally, the solid content concentration of the compound (A1) solution was calculated by (W2 / W1) × 100.

A part of the solution was sampled, and the weight average molecular weight was measured by GPC analysis (polystyrene standard). For GPC analysis, polystyrene having a molecular weight of 645 to 132,900 (polystyrene calibration kit PL2010-0102 manufactured by VARIAN) was used as standard polystyrene, and PLgel MIXED-D (manufactured by VARIAN) was used as the column, and the mobile phase was used. As THF, the column temperature was set to 35 ° C., and the measurement was performed using a differential refractive index detector. As a result, the weight average molecular weight of the compound (A1) was 3,200.

[Synthesis Example 2] Synthesis of Compound (A2) In a four-necked flask with a stirrer, propylene glycol monomethyl ether as a polymerization solvent, citraconic anhydride as a compound (a1), and 3-aminopropyltriethoxysilane as a compound (a2) are as follows. The weight was charged. The four-necked flask was heated in an oil bath set at 100 ° C. for 1 hour, and further set at 120 ° C. and aged for 2 hours.

A compound (A2) solution was obtained by a method according to Synthesis Example 1. The solid content concentration of the compound (A2) determined by the dry weight method was 41 wt%, and GPC analysis was performed in the same manner. As a result, the weight average molecular weight of the compound (A2) was 2,600.

[Synthesis Example 3] Synthesis of Compound (A3) In a four-necked flask with a stirrer, propylene glycol monomethyl ether as a polymerization solvent, itaconic anhydride as compound (a1), and 3-aminopropyltriethoxysilane as compound (a2) are as follows. The weight was charged. The four-necked flask was heated in an oil bath set at 100 ° C. for 1 hour, and further set at 120 ° C. and aged for 2 hours.

A compound (A3) solution was obtained by a method according to Synthesis Example 1. The solid content concentration of the compound (A3) determined by the dry weight method was 43 wt%, and GPC analysis was performed in the same manner. As a result, the weight average molecular weight of the compound (A3) was 3,000.

[Synthesis Example 4] Synthesis of Compound (A4) Four-necked flask with a stirrer is propylene glycol monomethyl ether as a polymerization solvent, citraconic anhydride as compound (a1), and 3-aminopropyltriethoxysilane as compound (a2) The weight was charged. The four-necked flask was heated in an oil bath set at 100 ° C. for 1 hour, and further set at 120 ° C. and aged for 2 hours.

Thereafter, the reaction solution was once cooled to about room temperature, and then 3.39 g of formic acid and 4.82 g of water were added to the reaction solution. The reaction was again carried out for 1 hour at an oil bath temperature of 100 ° C., and the low boiling point was distilled off at normal pressure while aging for 2 hours at a setting of 120 ° C.

A compound (A4) solution was obtained by a method according to Synthesis Example 1. The solid content concentration of the compound (A4) determined by the dry weight method was 39 wt%, and as a result of GPC analysis, the weight average molecular weight of the compound (A4) was 5,800.

[Synthesis Example 5] Synthesis of Compound (A5) In a four-necked flask with a stirrer, propylene glycol monomethyl ether as a polymerization solvent, itaconic anhydride as compound (a1), and 3-aminopropyltriethoxysilane as compound (a2) are as follows. The weight was charged. The four-necked flask was heated in an oil bath set at 100 ° C. for 1 hour, and further set at 120 ° C. and aged for 2 hours.

Thereafter, the reaction solution was once cooled to about room temperature, and then 3.39 g of formic acid and 4.82 g of water were added to the reaction solution. The reaction was again carried out for 1 hour at an oil bath temperature of 100 ° C., and the low boiling point was distilled off at normal pressure while aging for 2 hours at a setting of 120 ° C.

A compound (A5) solution was obtained by a method according to Synthesis Example 1. The solid content concentration of the compound (A5) determined by the dry weight method was 42 wt%, and as a result of GPC analysis, the weight average molecular weight of the compound (A5) was 6,000.

Synthesis Example 6 Synthesis of Compound (A6) In a four-necked flask with a stirrer, propylene glycol monomethyl ether as a polymerization solvent, maleic anhydride and citraconic anhydride as a compound (a1), and 3-aminopropyltrimethyl as a compound (a2) Ethoxysilane and dibutylhydroxytoluene as a polymerization inhibitor were charged in the following weights. The four-necked flask was heated in an oil bath set at 100 ° C. for 1 hour, and further set at 120 ° C. and aged for 2 hours.

A compound (A6) solution was obtained by a method according to Synthesis Example 1. The solid content concentration of the compound (A6) determined by the dry weight method was 39 wt%, and as a result of GPC analysis, the weight average molecular weight of the compound (A6) was 2,700.

[Comparative Synthesis Example 1] Synthesis of polymer (E1) In a four-necked flask with a stirrer, cyclopentanone as a polymerization solvent, a monomer of the following formula (e1), Dimethyl 2,2'-azobis (2-methylpropionate (Wako Pure Chemical) Industrial V-601) was charged at the following weight, and radical polymerization was performed at 80 ° C. for 3 hours to obtain a polymer (E1) solution having a solid content concentration of 30 wt%.

As a result of GPC analysis by a method according to Synthesis Example 1, the weight average molecular weight of the polymer (E1) was 9,500.

[Examples 1 to 6] and [Comparative Example 1]
As shown in the table below, compositions of Examples 1 to 6 and Comparative Example 1 were prepared and evaluated. The compounds (A1) to (A6) obtained in Examples 1 to 6 were each diluted with propylene glycol monomethyl ether to a solid content of 3 wt%. In Comparative Example 1, the polymer (E1) obtained in Comparative Synthesis Example 1 was diluted with cyclopentanone to 3 wt% and used. Here, solid content refers to components other than an organic solvent.

Abbreviations used in the table below are as follows.
Compound (a1)
MAH: maleic anhydride CAH: citraconic anhydride IAH: itaconic anhydride compound (a2)
APTES: 3-aminopropyltriethoxysilane organic solvent (B)
PGME: Propylene glycol monomethyl ether CPN: Cyclopentanone

[Evaluation of photo-alignment sensitivity after pre-bake]
The composition for photo-alignment film of Example 1 was spin-coated at a rotation speed of 1500 rpm for 10 seconds, and a thin film was formed on a glass substrate (Corning Co., Ltd. EagleXG, 40 mm × 40 mm × 0.7 mm). Next, it was dried at 130 ° C. for 5 minutes on a hot plate.

The film thickness of the dried thin film was measured with a profiler P-16 (a step / surface roughness / fine shape measuring device manufactured by KLA-Tencor Corporation). The film thickness was 93 nm.

The light irradiated from the ultra high pressure mercury lamp was converted into linearly polarized light through a filter that cuts light of 300 nm or less and a wire grid polarizing plate, and irradiated to the glass substrate coated with the thin film at a value of 10 mJ / cm ² (value at 313 nm).

Next, the polymerizable liquid crystal composition (1) was spin-coated on the substrate at a rotation speed of 1300 rpm for 10 seconds, and dried on a hot plate at 80 ° C. for 1 minute. After cooling the substrate to room temperature, the entire line of the ultra-high pressure mercury lamp was irradiated with 300 mJ / cm ² (value at 313 nm) to photocur the polymerizable liquid crystal composition to fix the alignment.

The prepared polymerizable liquid crystal photocured substrate was sandwiched between two polarizing plates in an orthogonal (crossed Nicols) state and observed by irradiating a backlight from below. The minimum exposure amount at which bright and dark display was possible without alignment defects (light loss), that is, “photo alignment sensitivity after pre-bake” was 10 mJ / cm ² .

[Evaluation of post-bake post-photoalignment sensitivity]
In the same manner as described above, a photo-alignment film was spin-coated on a glass substrate, dried at 130 ° C. for 5 minutes, and further post-baked at 230 ° C. for 30 minutes. Then, the light irradiated from the ultra-high pressure mercury lamp is converted into linearly polarized light through a filter that cuts light of 300 nm or less and a wire grid polarizing plate, and the glass substrate coated with the thin film is irradiated with 10 mJ / cm ² (value at 313 nm). did.

Next, the polymerizable liquid crystal composition (1) was spin-coated on the substrate at a rotation speed of 1300 rpm for 10 seconds, and dried on a hot plate at 80 ° C. for 1 minute. After cooling the substrate to room temperature, the entire line of the ultra-high pressure mercury lamp was irradiated with 300 mJ / cm ² (value at 313 nm) to photocur the polymerizable liquid crystal composition to fix the alignment.

The prepared substrate after fixing the polymerizable liquid crystal was sandwiched between two polarizing plates in an orthogonal (crossed Nicols) state and observed by irradiating a backlight from below. The minimum exposure amount at which bright and dark display was possible without alignment defects (light loss), that is, “post-bake post-bake photo-alignment sensitivity” was 10 mJ / cm ² .

[Board adhesion]
A cross-cut test was performed using the substrate after fixing the polymerizable liquid crystal prepared by the evaluation of the photo-alignment sensitivity. Both the substrate after the pre-bake photo-alignment sensitivity test and the substrate after the post-bake photo-alignment sensitivity test were not peeled off in all 100 squares after the tape was peeled off.

Further, in Examples 2 to 6 and Comparative Example 1, the same evaluation as in Example 1 was performed. The results are shown in Table 2 together with the results of Example 1. In Comparative Example 1, the photo-alignment sensitivity after the pre-bake was good, but the photo-alignment sensitivity after the post-bake was remarkably lowered, and the substrate adhesion was x. Since Comparative Example 1 was insoluble in propylene glycol monomethyl ether, which is an alcohol solvent, evaluation was performed using cyclopentanone having strong dissolving power.

The photo-alignment film of the present invention has excellent adhesion to the substrate, is soluble in an alcohol-based solvent (does not erode the flexible substrate), and can be manufactured at low cost, so that it can be used as a liquid crystal alignment film in a wide range of applications. Is possible.

Claims (5)

Obtained by reacting at least one acid anhydride (a1) selected from the group of compounds represented by formulas (1) and (2) with compound (a2) having amino and alkoxysilyl in the molecule The composition for photo-alignment films containing the polymer (A2) obtained by polymerizing a compound (A1) or a compound (A1), and an organic solvent (B).

In formula, R < ¹ >, R < ² > and R < ³ > are respectively independently hydrogen or a C1-C5 alkyl. The composition for photo-alignment films according to claim 1, wherein the acid anhydride (a1) is at least one selected from maleic anhydride, itaconic anhydride and citraconic anhydride. The compound (a2) having amino and alkoxysilyl in the molecule is selected from 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 4-aminophenyltrimethoxysilane, and 4-aminophenyltriethoxysilane The composition for photo-alignment films according to claim 1 or 2, wherein the composition is at least one. The photo-alignment film created using the photocurable composition described in any one of Claims 1-3. A display device manufactured using the photo-alignment film according to claim 4.