JP2007121721A - Composition for photo-alignment film, method for producing photo-alignment film, optically anisotropic body using the same, optical element and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photo-alignment film having high sensitivity and free of reduction in alignment control power even when exposed to a high temperature in production of a liquid crystal display element or in production of an optically anisotropic body, or exposed to an adhesive used in a seal member or a diluent solvent of a polymerizable liquid crystal or an alignment film material for use in production of an optically anisotropic body. <P>SOLUTION: There are provided a composition for a photo-alignment film containing a dichroic compound and amino resin, a method for producing a photo-alignment film including: applying the composition for a photo-alignment film on a substrate; illuminating light having anisotropy on the resultant coating film; and heating the film, and an optically anisotropic body obtained by applying a polymerizable liquid crystal composition on a photo-alignment film using the composition for a photo-alignment film, and polymerizing the composition in an aligned state. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a composition for a photoalignment film that is useful as a liquid crystal alignment film for a liquid crystal display element or an optical anisotropic body, and further relates to an optical anisotropic body using a photoalignment film made of the composition for a photoalignment film.

In the liquid crystal display device, the state of the molecular arrangement of the liquid crystal is changed by the action of an electric field or the like, and the change in the optical characteristics accompanying this is used for display. In many cases, the liquid crystal is used by being injected into a gap between two substrates. In order to align the liquid crystal molecules in a specific direction, a liquid crystal alignment film is disposed inside the substrate.
Recently, as an optical compensation sheet (retardation plate) which is a kind of optical anisotropic body used between a liquid crystal cell and a polarizing plate, an optical heterogeneity obtained by curing a polymerizable liquid crystal material in an aligned state. The demand for rectangular parallelepiped is increasing, and a liquid crystal alignment film is also used for this.

Conventionally, a rubbing film obtained by rubbing a polymer film such as polyimide in one direction with a cloth or the like is used as the liquid crystal alignment film. However, in the rubbing method, fine scratches on the surface of the polymer film due to mechanical rubbing may cause liquid crystal alignment defects, and uneven alignment may occur due to non-uniform pressing pressure during rubbing. There is a problem that the definition of the liquid crystal element is lowered.
In addition, the optical compensation sheet (retardation plate) is often used for the purpose of widening the wavelength band and improving the accuracy of the viewing angle. In that case, for example, a quarter wavelength plate and a half wavelength plate are used. Or a laminate of A-Plate and C-Plate. However, when the method for producing the laminate, that is, the step of curing the polymerizable liquid crystal layer after the production of the liquid crystal alignment film layer is repeated, the production method using the rubbing method becomes very large and the production is continuous. It is virtually impossible to do. Therefore, there has been a demand for a method for obtaining a liquid crystal alignment film that can continuously perform all the steps of laminating the liquid crystal alignment film and the liquid crystal layer.

In order to solve such a problem, a liquid crystal alignment film manufacturing technique that does not perform rubbing has recently attracted attention. In particular, the photo-alignment method, which obtains liquid crystal alignment by irradiating the coating film provided on the substrate with light having some anisotropy, is expected to be put to practical use because of its excellent mass productivity and compatibility with large substrates. ing.
Such photo-alignment films can be anisotropic, such as dichroic compounds that undergo photoisomerization reactions such as azobenzene derivatives, compounds that have photodimerization reactions such as cinnamate, coumarin, and chalcone, and polyimide. There are compounds that cause photolysis (see, for example, Non-Patent Document 1). Among them, the photo-alignment material that is currently considered to have the highest sensitivity and good orientation is a low-molecular dichroic compound that undergoes a photoisomerization reaction, such as an azobenzene derivative, and many studies have been made. . (For example, see Patent Document 1 and Non-Patent Document 2)
In addition, the sensitivity here means that the light irradiation energy required to obtain a sufficient alignment regulating force is small.

  Since low molecular dichroic compounds may have a small free volume necessary for molecular structure change by isomerization reaction, reorientation such as photoisomerization and thermal isomerization easily occurs. Thus, the small light energy required for molecular reorientation is a factor of high sensitivity and good orientation.

However, this property has a negative effect on the stability of the orientation regulating force. That is, if external energy that can cause re-orientation is given again, the orientation regulating power may be lost.
For example, in a manufacturing process of a liquid crystal display element, there is a process of bonding two substrates having a photo-alignment film through a spacer having a diameter of several microns. Since many of the adhesives (generally referred to as sealing agents) used at this time are thermosetting, the substrate is exposed to a high temperature in the bonding process. That is, external energy is again applied to the photo-alignment film, re-orientation of the dichroic compound is induced, and the alignment regulation power may be lost.
In addition, in the optical anisotropic process, in order to grow a liquid crystal phase into a monodomain after applying a liquid crystal material such as a polymerizable liquid crystal or a polymer liquid crystal on a photo-alignment film subjected to a photo-alignment treatment, An aging treatment may be required at a temperature just below the isotropic phase-liquid crystal phase transition temperature. Polymerizable liquid crystals and polymer liquid crystals have a higher transition temperature between the liquid crystal phase and the isotropic phase than non-polymerizable low-molecular liquid crystals used as drive liquid crystals for ordinary liquid crystal display elements. The aging time must be increased. Even in such an aging treatment step, the photo-alignment film is exposed to heat, re-orientation of the dichroic compound is induced, and the alignment regulation power may be lost.

In addition, the sealing agent used in the manufacturing process of the liquid crystal display element or the liquid crystal material used when creating the optical anisotropic body may cause the alignment regulating power of the photo-alignment film to be lost. That is, the sealing agent or the liquid crystal material may contain a general-purpose solvent, resin, additive, or the like in order to improve the coating property or adhesiveness, and the dichroic compound may be dissolved therein. As a result, the alignment of the photo-alignment film is disturbed, which is a major factor in losing the alignment regulating force.
In addition, in the case of obtaining a laminated optical anisotropic body that repeats the lamination of the liquid crystal alignment film and the liquid crystal layer, in the step of coating and creating the liquid crystal alignment film on the liquid crystal layer, two dilute solvents for the alignment film material are used. The chromatic compound may begin to dissolve and similar problems may occur.

  In order to deal with such problems, a polymerizable compound in which a polymerizable group is introduced into a dichroic compound having an azobenzene skeleton (see, for example, Patent Document 2), and a polymer compound having an azobenzene skeleton pendant (for example, Patent Document) 3), a composition obtained by adding a polymer to a low-molecular dichroic compound, and the like (for example, see Patent Document 4) have been studied.

  Since the dichroic compound having a polymerizable group introduced therein as in Patent Document 2 can be fixed by polymerization after being subjected to photo-alignment treatment, the reactivity to heat is suppressed or it is difficult to dissolve in a solvent. be able to. However, since the molecular volume is increased by introducing a polymerizable group, the free volume required for the molecular structure change due to photoisomerization increases, and the sensitivity of the photoisomerization reaction decreases.

  In addition, a polymer compound in which a dichroic molecule such as an azobenzene skeleton is pendant as in Patent Document 3 can suppress a decrease in the degree of orientational order due to heat at a temperature lower than the glass transition point, and can improve heat resistance or resist a solvent. A decrease in solubility can be expected. However, since the dichroic molecule is covalently bonded to the polymer main chain, the thermal motion of the dichroic molecule is limited, and the sensitivity of the photoisomerization reaction is lowered.

  Moreover, it is thought that the composition which added the polymer to the low molecular dichroic compound like patent document 4 is comprised so that the circumference | surroundings of a dichroic compound may be enclosed with a polymer, and, thereby, heat-resistant The improvement of the property or the decrease in the solubility in the solvent can be expected. However, in this method, the concentration of the dichroic compound is relatively lowered, and the sensitivity is greatly reduced in proportion to the amount of the added resin.

  Thus, the present situation is that a photo-alignment film having high sensitivity and whose alignment regulating force is not lowered by heat or a solvent has not yet been obtained.

Liquid Crystal, Vol.3, No.4, 262 (1999) Molecular Crystals and Liquid Crystals, 2000 (352), p27, Molecular Crystals and Liquid Crystals, 2001 (360), p81, Liquid Crystals, 2002 (29), p1321 Japanese Patent Laid-Open No. 5-232473 JP 2002-250924 A JP 7-247319 A Japanese Patent Laid-Open No. 11-133431

  The problem to be solved by the invention is high sensitivity, high temperature during liquid crystal display element production or optical anisotropic body production, or an adhesive used in a seal member or polymerizable liquid crystal used in optical anisotropic production. An object of the present invention is to provide a photo-alignment film in which the alignment regulating force does not decrease even when exposed to a dilution solvent of the alignment film material, and an optical anisotropic body and optical element using the same.

The inventors of the present invention have used a low-molecular dichroic compound with high sensitivity, and have studied a composition that does not lower the alignment regulation force by heat or a solvent without lowering the sensitivity of the compound.
In order not to lower the sensitivity of the dichroic compound, it is preferable to keep the free volume required for the structural change of the photoisomerization of the dichroic compound during orientation as small as possible. On the other hand, it is preferable to take away the degree of freedom of the dichroic molecule after the alignment treatment in order to obtain a photo-alignment film in which the alignment regulating force is not reduced by heat or a solvent, that is, the alignment is not disturbed.
As a result of diligent research under such an idea, a composition of a low molecular dichroic compound and a reactive compound having a relatively low molecular weight that becomes an amino resin after thermosetting has high sensitivity in the photo-alignment process. After the photo-alignment treatment, the inventors have found that the above-described reactive compound mixed with the dichroic molecule is thermally cured to generate a highly rigid amino resin around the dichroic dye, thereby solving the problem.
The reactive compound to be an amino resin has a small molecular volume before the reaction, and therefore does not hinder the free volume of the dichroic compound. The dichroic compound can maintain the sensitivity because the free volume required for the structural change of photoisomerization can be kept small. In addition, after the thermosetting of the reactive compound, the dichroic compound is surrounded by a highly rigid amino resin. Since the dichroic compound loses the free volume necessary for the photoisomerization reaction, the orientation is not disturbed by the heat or the solvent, and the dichroic compound does not dissolve in the solvent.

  That is, this invention provides the composition for photo-alignment films containing a dichroic compound and an amino resin.

  In addition, the present invention provides a method for producing a photo-alignment film in which the coating composition for photo-alignment film described above is applied on a substrate and then irradiated with light having anisotropy on the coating film. A method for producing a heated photo-alignment film is provided.

  The present invention also provides an optical anisotropic body obtained by applying a polymerizable liquid crystal composition on a photo-alignment film using the above-described composition for photo-alignment film and polymerizing the composition in an aligned state. .

  The present invention also includes a step 1 of applying the composition for a photoalignment film described above on a substrate, a step 2 of irradiating the coating film with anisotropic light, and a polymerizable liquid crystal composition. The method for producing an optical anisotropic body as described above, wherein the step 3 of polymerizing in the aligned state is performed in this order, and the step of curing the amino resin between the step 1 and the step 3 The manufacturing method of the optical anisotropic body which has these is provided.

  The present invention also provides an optical element using the above-described optical anisotropic body.

  The present invention also includes a step 1 of applying the composition for a photoalignment film described above on a substrate, a step 2 of irradiating the coating film with anisotropic light, and a polymerizable liquid crystal composition. The method for producing an optical element as described above, wherein Step 3 for obtaining an optical anisotropic body to be polymerized in an oriented state and Step 4 for obtaining an optical element on which the optical anisotropic body is installed are performed in this order. The manufacturing method of the optical element which has the process of hardening an amino resin between the said process 4 after 1 is provided.

  According to the invention, the sensitivity is high, the temperature at the time of liquid crystal display element production or optical anisotropic body production, or the diluent used for the polymerizable liquid crystal or polymer liquid crystal used for the production of adhesives or optical anisotropic bodies used for sealing members A photo-alignment film in which the alignment regulating force does not decrease even when exposed to light, an optical anisotropic body using the same, and an optical element can be provided.

(Dichroic compound)
The dichroic compound used in the present invention is preferably a compound having a photo-alignment group (hereinafter abbreviated as a photo-alignment group) that exhibits a liquid crystal alignment function by at least one photoisomerization reaction in one molecule. Particularly preferred are compounds having an azobenzene skeleton, anthraquinone skeleton, quinophthalone skeleton, perylene skeleton, and stilbene skeleton, in which the light absorption spectrum of the molecular chromophore varies depending on the direction of the polarization plane of linearly polarized light (hereinafter referred to as dichroism). , A compound having an azobenzene skeleton, an anthraquinone skeleton, or a stilbene skeleton is particularly preferable in that it exhibits good photo-alignment properties when irradiated with polarized light, and a compound having an azobenzene skeleton (hereinafter abbreviated as an azo compound) has the highest sensitivity to light. So most preferred.

  A well-known thing can be used as an azo compound used by this invention. For example, Direct Yellow 1, Direct Yellow 12, Direct Yellow 26, Direct Yellow 28, Disperse Yellow 7, Disperse Yellow 9, Acid Yellow 9, Acid Yellow 36, Acid Orange 8, Moldant Yellow 1, Moldant Yellow 10, Moldant yellow 12, etc. are mentioned.

  The azo compound used in the present invention preferably has a group having reactivity with the melamine resin. Examples of such a group include polar groups such as a hydroxyl group, an amino group, and a carboxyl group. Of these, a hydroxyl group is preferred.

  The azo compound used in the present invention may have a polymerizable group. Examples of the azo compound having a polymerizable group include a carboxylic acid having a polymerizable group, a carboxylic acid chloride having a polymerizable group, and a carboxylic acid anhydride having a polymerizable group by a known method. , Etc. can be easily synthesized. An azo compound having a hydroxy group can be easily synthesized by a known method.

(Polymerizable group)
Examples of the polymerizable group include (meth) acryloyl group, (meth) acryloyloxy group, (meth) acrylamide group, vinyl group, vinyloxy group, maleimide group, azide group, chloromethyl group, epoxy group, and the like. Examples of the derivative having a polymerizable group include cinnamic acid derivatives and thymine derivatives. Among these, (meth) acryloyl group, (meth) acryloyloxy group, maleimide group, (meth) acrylamide group, vinyl group and vinyloxy group are preferable because photopolymerization and thermal polymerization are relatively easy. An acryloyl group, a (meth) acryloyloxy group, a maleimide group, or a (meth) acrylamide group is more preferable. These polymerizable groups may be bonded to an azobenzene derivative via a linking group such as an alkylene group and / or a phenylene group, and the linking group includes an ester bond, an ether bond, an imide bond, or an amide bond. You may have.
When a compound having a photo-alignable group has a polymerizable group, after photo-alignment, after a cooling step, the orientation is increased, and then the alignment state is polymerized using the polymerizable group to fix the alignment. It is preferable to do.

  Among the azo compounds used in the present invention, the compound represented by the general formula (1) exhibits high solubility in water or a polar organic solvent, and exhibits good affinity for glass and the like. A composition for a photo-alignment film formed by dissolving the compound in water or a polar organic solvent is applied to a substrate such as glass, and then the water or the polar organic solvent is removed. A coating film for a photo-alignment film can be formed.

In general formula (1), R ¹ and R ² are each independently a hydroxy group or amino group, carboxyl group, (meth) acryloyl group, (meth) acryloyloxy group, (meth) acrylamide group, vinyl group, It represents a polymerizable functional group selected from the group consisting of a vinyloxy group and a maleimide group. It is preferable that R ¹ and R ² are a hydroxyl group, an amino group, or a carboxyl group, because the chemical reaction with the amino resin improves the stability to light and heat. In addition, it is preferable that R ¹ and R ² are polymerizable functional groups because the thermal motion of the photo-alignment film molecules is suppressed by the polymerization operation after the photo-alignment treatment, so that the stability to light and heat is improved. Among the polymerizable groups, a (meth) acryloyloxy group is particularly preferable. A maleimide group is more preferable because a polymerization initiator is not required.

X ¹ represents a single bond when R ¹ is a hydroxy group, and represents a linking group represented by — (A ¹ -B ¹ ) _m — when R ¹ is a polymerizable functional group, and X ² represents R ^{When 2} is a hydroxy group, it represents a single bond, and when R ² is a polymerizable functional group, it represents a linking group represented by-(A ² -B ² ) _n- . Here, A ¹ and A ² each independently represent a single bond or a divalent hydrocarbon group.
Divalent hydrocarbon groups include methylene, ethylene, trimethylene, tetramethylene, pentamethylene, hexamethylene, heptamethylene, octamethylene, nonamethylene, decamethylene, undecamethylene, A linear alkylene group having 1 to 18 carbon atoms such as a methylene group; 1-methylethylene group, 1-methyltriethylene group, 2-methyltriethylene group, 1-methyltetraethylene group, 2-methyltetraethylene group, A branched alkylene group having 1 to 18 carbon atoms such as 1-methylpentamethylene group, 2-methylpentamethylene group, 3-methylpentamethylene group; phenylene group such as p-phenylene group; 2-methoxy-1,4 -Phenylene group, 3-methoxy-1,4-phenylene group, 2-ethoxy-1,4-phenylene group, 3-eth A phenylene group having a linear or branched alkoxy group having 1 to 18 carbon atoms such as cis-1,4-phenylene group and 2,3,5-trimethoxy-1,4-phenylene group; 2,6-naphthalene An arylene group such as a diyl group may be mentioned.

B ¹ and B ² are each independently a single bond, —O—, —CO—O—, —O—CO—, —CO—NH—, —NH—CO—, —NH—CO—O—, or -O-CO-NH- is represented. m and n each independently represents an integer of 0 to 4. However ^{A 1} is bonded to ^{R 1, A 2} binds to ^{R 2.}
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.

R ³ and R ⁴ each independently represent a hydrogen atom, a halogen atom, a carboxyl group, a halogenated methyl group, a halogenated methoxy group, a cyano group, a nitro group, or —OR ⁷ (wherein R ⁷ has 1 to 6 represents a lower alkyl group having 6 to 6 carbon atoms, a lower alkyl group having 1 to 6 carbon atoms substituted by a cycloalkyl group having 3 to 6 carbon atoms or a lower alkoxy group having 1 to 6 carbon atoms), and 1 to 4 carbon atoms A hydroxyalkyl group, or —CONR ⁸ R ⁹ (R ⁸ and R ⁹ each independently represents a hydrogen atom or a lower alkyl group having 1 to 6 carbon atoms), or a methoxycarbonyl group. However, the carboxyl group may form a salt with the alkali metal.
Examples of the halogen atom include a fluorine atom and a chlorine atom. Examples of the halogenated methyl group include a trichloromethyl group and a trifluoromethyl group. Examples of the halogenated methoxy group include a chloromethoxy group and a trifluoromethoxy group.
Examples of the lower alkyl group having 1 to 6 carbon atoms represented by R ⁷ include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, and a 1-methylethyl group. Examples of the lower alkyl group having 1 to 6 carbon atoms substituted by the lower alkoxy group having 1 to 6 carbon atoms represented by R ⁷ include methoxymethyl group, 1-ethoxyethyl group, tetrahydropyranyl group and the like. It is done.
Examples of the hydroxyalkyl group having 1 to 4 carbon atoms include hydroxymethyl group, 1-hydroxyethyl group, 2-hydroxyethyl group, 1-hydroxypropyl group, 2-hydroxypropyl group, 3-hydroxypropyl group, 1-hydroxy A butyl group etc. are mentioned.
Examples of the alkyl group having 1 to 6 carbon atoms represented by R ⁸ and R ⁹ include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, and a 1-methylethyl group.
Among these, a halogen atom, carboxyl group, halogenated methyl group, halogenated methoxy group, methoxy group, ethoxy group, propoxy group, hydroxymethyl group, carbamoyl group, dimethylcarbamoyl group, and cyano group are preferable, carboxyl group, hydroxymethyl The group or the trifluoromethyl group is particularly preferable in that good orientation can be obtained.
Y represents a single bond, —C═C—, —C≡C═. A single bond and —C═C— are preferable because of high sensitivity of the photoisomerization reaction, and a single bond is more preferable.

Moreover, when R ³ and R ⁴ are substituted at the meta positions of the phenylene group at both ends of the 4,4′-bis (phenylazo) biphenyl skeleton, an excellent photoalignment film can be obtained, which is particularly preferable. R ³ and R ⁴ are particularly preferably substituted at the following structural formulas because an excellent alignment film can be obtained.

Ｒ^５およびＲ^６は各々独立して、カルボキシル基、スルホ基、ニトロ基、アミノ基、カルバモイル基又はヒドロキシ基を表す。但し、カルボキシル基、スルホ基は、リチウム、ナトリウム、カリウム等のアルカリ金属と塩を形成していても良い。これらの中でも、基板表面に均一に光配向膜を形成するためにはガラスやＩＴＯなどの透明電極に親和性が高い官能基が好ましく、カルボキシル基又はその塩、スルホ基又はその塩が特に好ましい。また、Ｒ^５およびＲ^６は、４，４’−ビス（フェニルアゾ）ビフェニル骨格の２、２’位に置換していると、優れた光配向性が得られ、特に好ましい。また、Ｒ^５およびＲ^６は、優れた光配向性が得られることから、下記構造式の置換位置が特に好ましい。

R ⁵ and R ⁶ each independently represent a carboxyl group, a sulfo group, a nitro group, an amino group, a carbamoyl group or a hydroxy group. However, the carboxyl group and the sulfo group may form a salt with an alkali metal such as lithium, sodium or potassium. Among these, in order to form a photo-alignment film uniformly on the substrate surface, a functional group having high affinity for a transparent electrode such as glass or ITO is preferable, and a carboxyl group or a salt thereof, a sulfo group or a salt thereof is particularly preferable. Further, it is particularly preferable that R ⁵ and R ⁶ are substituted at the 2,2 ′ positions of the 4,4′-bis (phenylazo) biphenyl skeleton, because excellent photoalignment properties can be obtained. R ⁵ and R ⁶ are particularly preferably substituted at the following structural formulas because excellent photo-orientation properties can be obtained.

Examples of the azo compound represented by the general formula (1) include compounds described in JP-A-5-232473. Among these, an azo compound having the following structure is preferable.

  The compounds having a photoalignable group used in the present invention can be used alone or in combination of two or more.

(Amino resin)
In the present invention, the amino resin refers to those which are generally used as a crosslinking agent / curing agent, such as those having an amino group, a methylol group, or an alkoxymethyl group, and become an amino resin after curing. Examples of such amino resins include melamine resins and benzoguanamine resins. These amino resins can be obtained by condensing formaldehyde and alcohol as necessary to melamine, benzoguanamine, etc. by a known method, but they are highly acetalized (alkyl etherified) with few amino groups or methylol groups. It is preferable to use the prepared one because the composition for photo-alignment film of the present invention hardly reacts with time, is excellent in stability over time, and can suppress the self-condensation of melamine during heat curing. . More specifically, the average number of methylol groups etherified with methanol, n-butanol, isobutanol, or the like per one triazine ring is preferably 2.5 or more. Further, if the molecular volume is too large, the orientation of the dichroic compound may be hindered during the photo-alignment treatment, so the average degree of condensation is preferably 6 or less, more preferably 3 or less, and even more preferably 1.0 to 2.5 is preferred. For the same reason, the weight average molecular weight is preferably 3000 or less, and preferably 300 to 2500.

  Specifically, for example, Super Becamine L-164, Super Becamine L-152-60 [all manufactured by Dainippon Ink and Chemicals], My Coat 506, My Coat 508 [All manufactured by Cytec Industries, USA], BR -28, BR-20SE, BR-220, BR-21R, BR-22R [all made by Changchun Artificial Resin Taiwan], etc .; Cymel 300, Cymel 301, Cymel 303, Cymel 325, Cymel 327, Cymel 350 , Cymel 370, Cymel 703, Cymel 712, My Coat 715 (all manufactured by Cytec Industries, USA), Nicarak MW-30M, Nicarak MW-30HM, Nicarac MW-30, Nicarac MW-22, Nicarac MW-390, Nicarac W-100LM, Nicarak MS-11, Nicarak MS-15, Nicarak MS-17, Nicarak MS-001, Nicarak MX-035, Nicarax MX-706, Nicarak MX-730, Nicarac MX-750, Nicarac MX-750LM [three Sumika M-100C, Sumimar M-55, Sumimar M-56T, Sumimar M-40ST, Sumimar M-50WT, Sumimar M-40WT, Sumimar M-30W (both made by Changchun artificial resin, Taiwan), Resimin Methyl etherified melamine such as 741 [manufactured by Monsanto]; Cymel 202, Cymel 207, Cymel 211, Cymel 232, Cymel 235, Cymel 236, Cymel 238, Cymel 254, Cymel 266, Cymel 267, Cymel 272, Cymel 285, Cymel 1130, My Coat 212 [all manufactured by Cytec Industries, USA], Nicarax MX-45, Nicarak MX-410, Nicarak MX-485, Nicarak MXP485, Nicarak MX-487, Nicarac MXP487 [all Sanwa Chemical], BEETLE BE3020, BEETLE BE3021, BEETLE BE3751 [manufactured by BIP Ltd., UK], and the like.

  Moreover, you may use together the said amino resin, an acid anhydride group containing compound, and / or its monoester. Since the acid anhydride group-containing compound and / or monoester thereof also serves as a reactive diluent, the content of the organic solvent can be reduced. Specifically, trimellitic acid, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, tetrachlorophthalic anhydride, methylhexahydrophthalic anhydride, het anhydride, anhydrous hymic acid ("Himic acid" It is a registered trademark of Hitachi Chemical Co., Ltd. ), Various acid anhydride group-containing low molecular weight compounds such as maleic anhydride, succinic anhydride, itaconic anhydride, methacrylic anhydride, pyromellitic anhydride, glycerol tris (trimellitate), etc. And hexahydrophthalic anhydride monomethyl ester, hexahydrophthalic anhydride monobutyl ester, tetrachlorophthalic anhydride monobutyl ester and the like obtained by esterifying these acid anhydride group-containing compounds with alcohols and the like. These number average molecular weights are preferably 1,000 or less and more preferably 700 or less in consideration of dilution performance.

The amino resin and a resin having a group capable of reacting with the amino resin, for example, a reactive functional group such as a hydroxyl group, an amino group, or a carboxy group can be used in combination. As the resin having a reactive functional group capable of reacting with these amino resins, known resins can be used, for example, polyester polyol resin, acrylic polyol resin, polyvinyl alcohol resin, polyvinyl butyral resin, epoxy resin, Phenol novolac resin, cresol novolak resin, aromatic hydrocarbon formaldehyde resin modified phenol resin, dicyclopentadiene phenol addition type resin, phenol aralkyl resin, naphthol aralkyl resin, trimethylol methane resin, tetraphenylol ethane resin, naphthol novolak resin, naphthol -Phenol co-condensed novolak resin, naphthol-cresol co-condensed novolak resin, biphenyl-modified phenol resin, aminotriazine-modified phenol resin and these Such as sex object can be used. In particular, it is preferable to use acrylic polyol, polyester polyol, polyvinyl butyral and the like containing a large amount of hydroxyl groups.
In the present invention, in the photo-alignment treatment stage, it is not preferable to add a large amount of an additive that deprives the free volume of the dichroic compound. Therefore, a resin having a group capable of reacting with the amino resin is used. In such a case, it is preferable to keep the addition amount small. Specifically, the total amount of polar functional groups that react with reactive functional groups such as alkoxy groups, methylol groups, and imino groups of amino resins is 2 to 1/10 times the total amount of reactive functional groups of amino resins. It is preferable that the amount is 1 to 1/10 times the amount, more preferably 1 to 1/5 times the amount. When this is defined with respect to the total amount of the composition for photo-alignment films, the resin having a group capable of reacting with the amino resin is preferably 25% by mass or less, preferably 20% by mass or less, and more preferably 10% by mass or less. .

  It is also effective to use the amino resin in combination with a curing catalyst. Examples of the curing catalyst include known and commonly used heat curing type acid catalysts for various amino resins. For example, aromatic sulfonic acids such as p-toluenesulfonic acid are preferably used. Representative catalysts include strong acid catalysts such as aromatic sulfonic acid catalyst 4040, catalyst 4050, catalyst 600, catalyst 602, and catalyst 500 (all manufactured by Cytec Industries, USA), phosphoric acid catalyst. Examples include weak acid catalysts such as List 296-9 (made by Cytec Industries, USA). Needless to say, the catalyst is not limited to these exemplified catalysts, and any compound that generates protons can be used, or these can be used alone or as a mixture of two or more.

  Moreover, the low molecular compound which has reactive functional groups, such as the said amino resin and the group which can react with the said amino resin, for example, a hydroxyl group, a phenol group, an amino group, a carboxy group, can also be used together. As the low molecular weight compound having these reactive functional groups, known and commonly used compounds can be used, and examples thereof include polymerizable low molecular weight compounds such as epoxy (meth) acrylate, polyhydric alcohols, and diamine compounds. . A low molecular compound having a polymerizable group such as epoxy (meth) acrylate is preferable because a covalent bond can be generated with both the photo-alignment film and the polymerizable liquid crystal.

(Mixing ratio)
The compounding ratio of the dichroic compound and the amino resin is not particularly limited, but if the amount of the dichroic compound added is too small, there is a possibility that sufficient alignment control force cannot be obtained, and the addition of the amino resin. If the amount is too small, sufficient resistance to the solvent may not be obtained. Usually, it is preferable to mix | blend so that dichroic compound: amino resin may be set to 100: 120-100: 5. The ratio is preferably 100: 100 to 100: 5, and most preferably 100: 40 to 100: 10. In the present invention, even if the amino resin amount is close to the same amount as that of the dichroic compound, the irradiation energy required for the photo-alignment treatment is not increased, and the sensitivity is maintained. This is a feature that is greatly different from a composition for a photo-alignment film comprising a mixture of a dichroic compound and another polymer material.

(Curing temperature)
The curing temperature of the amino resin used in the present invention is preferably in the range of 100 to 300 ° C. If the dichroic dye is a basic compound, the curing temperature is preferably high, specifically 150 to 300 ° C, preferably 150 ° C to 250 ° C, and more preferably 170 ° C to 240 ° C.
When the dichroic compound is an acidic substance or an acid catalyst is added, the curing temperature can be lowered. Specifically, the range of 100 to 250 ° C is preferable, 120 to 220 ° C is more preferable, and 120 ° C to 180 ° C is more preferable.

(solvent)
The composition for photo-alignment films used in the present invention usually uses a solvent for the purpose of improving the coatability. Although there is no limitation in particular as a solvent used for a solvent, The solvent in which the said compound shows favorable solubility is used. For example, inorganic solvents such as water, alcohol solvents such as methanol, ethanol, propanol, isopropanol, normal butanol and 2-butanol, diol solvents such as ethylene glycol, propylene glycol and 1,3-butanediol, tetrahydrofuran, 2- Ether solvents such as methoxyethanol, 2-butoxyethanol, 2- (2-ethoxyethoxy) ethanol, 2- (2-butoxyethoxy) ethanol, 2-pyrrolidone, N-methylpyrrolidone, dimethylformamide, dimethylacetamide, etc. Examples include amide solvents, γ-butyrolactone, chlorobenzene, dimethyl sulfoxide, and the like. These can be used alone or in combination of two or more. Moreover, you may add a well-known and usual additive in the range which does not impair the effect of this invention.
Usually, it prepares so that solid content ratio may be 0.2 mass% or more. It is preferable to prepare so that it may become 0.5-10 mass% especially.

(Additive)
In order to uniformly apply the composition for photo-alignment film used in the present invention and obtain a photo-alignment film having a uniform film thickness, a general-purpose additive can be used. For example, leveling agents, thixotropic agents, surfactants, ultraviolet absorbers, infrared absorbers, antioxidants, surface treatment agents, PH preparation agents, and other additives can be added to such an extent that the liquid crystal alignment ability is not significantly reduced. .

(Photo-alignment film, optical anisotropic body having photo-alignment film or method for producing optical element)
In order to obtain a photo-alignment film by using the composition for photo-alignment film of the present invention, the composition for photo-alignment film has anisotropy such as ultraviolet light or visible light after coating and drying on the substrate. Irradiate light to align the compound having photoalignment. Then, a photo-alignment film can be obtained by hardening an amino resin. This makes it possible to withstand high temperatures during the thermosetting process of sealing members such as liquid crystal display cells, and to use raw materials used by the sealing members, such as curable compounds (epoxy compounds and acrylic adhesives for epoxy adhesives). If there is an acrylate or the like) or an organic solvent used for the purpose of dilution, a liquid crystal display cell having a uniform display portion can be obtained.
In addition, after applying the composition for photo-alignment film on the substrate, it is heated and solvent-dried to produce a semi-cured state of the amino resin, and then light having anisotropy such as ultraviolet light or visible light. The compound having photo-alignment property may be aligned. In the semi-cured state, the free alignment necessary for the photoisomerization of the dichroic dye in the photo-alignment film material is compatible with the low solubility in the organic solvent that is a component of the seal member. The application of the sealing member to the substrate is preferable because the photo-alignment film composition can be suppressed from being dissolved into the sealing member. The main curing of the amino resin may be performed simultaneously with the curing of the seal member, or the amino resin may be thermally cured as a separate process.

Moreover, in order to obtain an optical anisotropic body using the composition for photo-alignment films of the present invention, a polymerizable liquid crystal is applied on the photo-alignment film described above and polymerized in an aligned state. Usually, Step 1 for applying the composition for a photoalignment film described above on a substrate, Step 2 for irradiating the coating film with anisotropic light, and applying and aligning a polymerizable liquid crystal composition. Step 3 of polymerizing in the state is performed in this order.
The step of curing the amino resin is not particularly limited, and may be performed after the step 1 to the step 3; however, if the polymerizable liquid crystal composition is applied and polymerized, the step is performed. It has been found that the solvent resistance and the like of the optical anisotropic body are improved while maintaining the alignment regulating force of the alignment film. Although the detailed reason such as the reaction mechanism is not clear, the method is a preferable method because the heating step can be provided at the very end of the coating step, the alignment step, and the polymerization step, and the manufacturing method can be simplified. is there.

In addition, after applying the composition for photo-alignment film on the substrate, it is heated and solvent-dried to produce a semi-cured state of the amino resin, and then light having anisotropy such as ultraviolet light or visible light. May be used to align a compound having photo-alignment properties. In the semi-cured state, the substrate that has been subjected to photo-alignment treatment is compatible with ensuring the free volume necessary for photoisomerization of the dichroic dye in the photo-alignment film material and low solubility in the polymerizable liquid crystal and its diluting solvent. By applying the polymerizable liquid crystal to the liquid crystal, it can be suppressed that the photo-alignment film composition is dissolved out to the polymerizable liquid crystal side. The main curing of the amino resin may utilize the heat of the aging process of the polymerizable liquid crystal, or a separate thermosetting process of the amino resin may be provided after the photo-curing of the polymerizable liquid crystal.
In some cases, optical anisotropic bodies can be laminated over several layers. In that case, the above process may be repeated a plurality of times, and an optically anisotropic laminate can be formed.

Or in order to obtain an optical element using the composition for photo-alignment films of the present invention, Step 1 for applying the above-described composition for photo-alignment films on a substrate and the coating film has anisotropy The step 2 of irradiating light, the step 3 of obtaining an optically anisotropic body to be polymerized in a state where the polymerizable liquid crystal composition is applied and aligned, and the step 4 of obtaining an optical element provided with the optically anisotropic body are performed. Do in order. The step of curing the amino resin may be performed after the step 1 and after the step 4, but for the same reason as the step of obtaining the optical anisotropic body, the step 3 of applying the polymerizable liquid crystal composition and Putting it in the step 4 of obtaining the optical element in which the optical anisotropic body is installed can improve the heat resistance and solvent resistance of the photo-alignment film by curing the amino resin while maintaining the alignment regulating force of the photo-alignment film. It is preferable for the reason.
A method put between the step 3 of applying the polymerizable liquid crystal composition and the step 4 of obtaining the optical element provided with the optical anisotropic body is preferable because the manufacturing method can be simplified.

The amino resin curing process may utilize a heating process incorporated in a manufacturing process of a liquid crystal display cell having an optical alignment film as a constituent member, an optical anisotropic body, an optical element, or the like.
For example, in a liquid crystal display cell, there is a step of thermally bonding two substrates with an alignment film with a sealant, and the amino resin can be cured using the heat. In this case, a curing catalyst or an additive capable of controlling the reaction temperature during the melamine curing reaction is appropriately added to the composition for a photo-alignment film, and the temperature of the melamine curing reaction and the curing temperature of the sealing agent are matched. Further preferred. This method is preferable because the manufacturing process of the liquid crystal display cell can be shortened.
In the case of an optical anisotropic body, there is an aging step, but the heat may be used. For example, when preparing a laminated body of optically anisotropic bodies, the step 1 of applying the composition for photo-alignment film on the substrate, the solvent drying of the composition for photo-alignment film, and the semi-curing of the amino resin are simultaneously performed. Heating step 2, step 3 for irradiating the coating film with anisotropic light, step 4 for applying the polymerizable liquid crystal composition and polymerizing it in an aligned state to obtain an optical anisotropic body, and amino A method in which the main curing of the resin and the heating step 5 for simultaneously performing aging of the optical anisotropic body are performed in this order is preferable because there is a merit that the heating step can be made common.
In any of the above cases, the heating temperature is preferably in a range not exceeding the temperature at which rearrangement of the composition for photo-alignment films is induced.

  In the case of producing an optical anisotropic body or an optical element, when a polymer liquid crystal is used instead of the polymerizable liquid crystal, the step 1 for applying the composition for a photo-alignment film on the substrate, Heating process 2 for simultaneously performing solvent drying of the product and semi-curing of the amino resin, process 3 of irradiating the coating film with anisotropic light, and applying a polymer liquid crystal composition to apply the polymer liquid crystal A heating step includes a step 4 for performing heating for simultaneously performing aging for aligning in a monodomain and a main curing of an amino resin, and a step 5 for fixing the alignment state of the polymer liquid crystal by cooling in this order. Can be used in common, and is efficient.

(Coating, substrate)
The composition for photo-alignment film used in the present invention is applied on a substrate by a known and common method such as spin coating method, gravure printing method, flexographic printing method, ink jet method, die coating method, cap coating method, dipping method. The coating film for photo-alignment film is obtained by drying. The substrate to be used is a substrate usually used for liquid crystal display elements and optical anisotropic bodies, and has a solvent resistance that can withstand heating during the drying after the application of the composition solution for photo-alignment film or during the production of the liquid crystal element. If it is a material which has heat resistance, there will be no restriction | limiting in particular. Examples of such a substrate include a glass substrate, a ceramic substrate, a metal substrate, a polymer material substrate, and the like. As the polymer material substrate, cellulose derivatives, polycycloolefin derivatives, polyesters, polyolefins, polycarbonates, polyacrylates, polyarylates, nylons, polystyrenes, polyether sulfones, polyvinyl alcohols, and the like can be used. In order to improve the applicability and adhesion of the composition for photo-alignment films, surface treatment of these substrates may be performed. Examples of the surface treatment include ozone treatment and plasma treatment. In order to adjust light transmittance and reflectance, an organic thin film, an inorganic oxide thin film, a metal thin film, or the like may be provided on the substrate surface by a method such as vapor deposition.
Usually, since the solution diluted with the organic solvent is applied, it is dried after application to obtain a coating film for a photo-alignment film.

(Photoisomerization process)
The coating film for photo-alignment film obtained by the above method is irradiated with light having anisotropy to give a liquid crystal alignment function (hereinafter abbreviated as a photoisomerization step), and photoisomerized coating for photo-alignment film. Create a membrane.
The anisotropic light used in the photoisomerization step includes polarized light such as linearly polarized light and elliptically polarized light, or non-polarized light from a direction oblique to the substrate surface. 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 or the like in order to obtain polarized light in the light irradiation device, there is a disadvantage that the light intensity irradiated to the film surface is reduced. The irradiation method does not require a polarizing filter or the like in the irradiation device, and has 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 to the substrate. In consideration of the uniformity of the irradiation energy on the irradiated surface, the pretilt angle obtained, the alignment efficiency, etc. A range of 60 ° is more preferred and 45 ° is most preferred.
The light to be irradiated may be light in a wavelength region in which the photo-alignment group of the compound to be used has absorption. For example, when the photo-alignment group has an azobenzene structure, ultraviolet rays having a wavelength of 330 to 550 nm that have strong absorption due to the π → π ^* transition of azobenzene are particularly preferable.

As a light source of irradiation light, an ultraviolet light source such as a xenon lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a metal halide lamp, an ultraviolet light laser such as KrF, ArF, and a nitrogen laser, a visible light laser such as an Ar ion laser, etc. Is mentioned. In particular, when the photo-alignment group has an azobenzene structure, it is possible to effectively use an ultra-high pressure mercury lamp having a particularly large emission intensity of ultraviolet light at 365 nm.
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.

  Further, when irradiating polarized light, if a photomask is used, liquid crystal alignment ability can be generated in two or more different directions in a pattern on the photo-alignment film. Specifically, after the composition for photo-alignment film of the present invention is applied and dried, the substrate 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 a plurality of times as necessary, liquid crystal alignment ability can be generated in a plurality of directions.

Further, in some cases, the photo-alignment film can be cooled after the photoisomerization step. As a cooling method, the photo-isomerized coating film for the photo-alignment film may be cooled. For example, the entire substrate is cooled by a known and common cooling device such as a cold plate, a chamber, or a low-temperature thermostat.
The cooling condition is that the cooling temperature is 20 ° C. for 1 minute or longer, but this is not the case when the cooling temperature is lower than 20 ° C. Although it should just be more than melting | fusing point of the solvent to be used as a cooling temperature, the range of -40 degreeC-20 degreeC is preferable normally. In order to obtain a more stable photo-alignment film with improved liquid crystal alignment function, the temperature is preferably 10 ° C. or less, and the cooling time is preferably 5 minutes or more. In order to further shorten the cooling time, the cooling temperature is preferably 5 ° C. or lower.
In order to prevent condensation, the cooling may be performed in a dry air, nitrogen, or argon atmosphere, or the substrate may be cooled while blowing dry air, nitrogen, or the like onto the substrate.

(Heating process)
Next, the amino resin is cured. When the curing is performed by heat, it is performed after the photoisomerization step. The heating method may be a known method, and usually the whole substrate is heated. The heating temperature depends on the reaction rate of the amino resin, the curing agent, and the curing accelerator to be used, but is usually preferably in the range of 100 to 300 ° C, particularly preferably in the range of 120 to 250 ° C, and in the range of 140 to 230 ° C. Is more preferable.
As described above, the heating step may be incorporated in any step among the steps of creating the target photo-alignment film, optical anisotropic body, or optical element as long as it is after the photoisomerization step. When an optical anisotropic body is obtained, it is preferable to incorporate a heating step after forming a coating film of polymerizable liquid crystal. In this case, although the reason is not clear, the solvent resistance of the optical anisotropic body as a laminate of the photo-alignment film and the polymerizable liquid crystal can be further improved. This method is effective for obtaining a laminated body of optical anisotropic bodies composed of a plurality of layers.
When obtaining an optical anisotropic body using the photo-alignment film of the present invention, there is a step of polymerizing a polymerizable liquid crystal composition. When heat is used as the polymerization method, the amino resin in the photo-alignment film is simultaneously cured. be able to.

  When the dichroic compound used in the present invention has a polymerizable group, the orientation state can be fixed after the photoisomerization step. In that case, it carries out by irradiating an active energy ray or heating. As the active energy ray, light having a wavelength different from that used in the photo-alignment operation, that is, light in a wavelength region that is not absorbed by the photo-alignment group of the compound used in the composition for the photo-alignment film is preferable. It is preferable to irradiate non-polarized ultraviolet light having a wavelength of 200 to 320 nm. In addition, a compound that absorbs light having a wavelength longer than the light absorption band of the photo-alignment group and induces a polymerization reaction by causing energy transfer may be mixed. Moreover, you may irradiate the polarized light which vibrates in the direction orthogonal to the direction of the absorption transition moment of a dichroic compound. Since polarized light orthogonal to the absorption transition moment is not absorbed by the dichroic dye, the alignment state is not disturbed even if the wavelength of the light to be polymerized and the wavelength of the light used in the photo-alignment operation are the same. By these, it can superpose | polymerize, without disturbing the orientation state of the composition for photo-alignment films | membranes fixed by photo-alignment operation. On the other hand, when the polymerization step is performed by heating, it can be performed in combination with the heating step.

  Since the photo-alignment film of the present invention is cured by adding an amino resin, it is used for the purpose of adjusting the viscosity of an existing sealant, for example, solvent naphtha, decalin, toluene, xylene, p-cymene, Hydrocarbon solvents such as α-pinene, p-menthane, turpentine oil, halogenated hydrocarbon solvents such as dichloropentane, alcohol solvents such as n-butanol, isobutanol, n-hexanol, 2-methylcyclohexanol, Diol solvents such as ethylene glycol and propylene glycol, ether systems such as 2-ethoxyethanol, 2-butoxyethanol, 2- (ethoxyethoxy) ethanol, 2- (butoxyethoxy) ethanol, diethylene glycol diethyl ether, and 1,4-dioxane Solvent, ethylene glycol monomethyl ester Ether ester solvents such as teracetate and ethylene glycol monoethyl ether acetate, ester solvents such as ethyl ethoxypropionate and dimethyl malonate, ketone solvents such as methyl isobutyl ketone, mesityl oxide, phorone and cyclohexanone; Resistant to solvents such as diethyl acetal, diacetone alcohol, dimethylformamide, dimethyl sulfoxide, N-methyl-2-pyrrolidone.

(Polymerizable liquid crystal composition)
The polymerizable liquid crystal composition used when obtaining the optical anisotropic body using the photo-alignment film obtained in the present invention has a polymerizable group that exhibits liquid crystallinity alone or in a composition with another liquid crystal compound. It is a liquid crystal composition containing the compound which has. 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 sylene group are connected, and a polymerizable functional group such as a (meth) acryloyl group, a vinyloxy group, and an epoxy group, or JP 2004-2373 A A rod-like polymerizable liquid crystal compound having a maleimide group as described in JP-A-2004-99446, Or a rod-like polypolar liquid crystal compound having an allyl ether group as described in JP-A No. 2004-149522, or, for example, Handbook of Liquid Crystals (D. Demus, J. W. Goodby, GW). Gray, H. W. Spiess, V. Vill, published by Wiley-VCH, 1998), Quarterly Chemical Review No. 22. Liquid crystal chemistry (edited by Chemical Society of Japan, 1994) and discotic polymerizable compounds described in JP-A-07-146409.

(Polymerization initiator)
In general, the polymerizable liquid crystal composition is polymerized by irradiation with light such as ultraviolet rays or heating. As the photopolymerization initiator used in the case of carrying out by light irradiation, known and conventional ones can be used, for example, 2-hydroxy-2-methyl-1-phenylpropan-1-one (“Darocur 1173” manufactured by Merck), 1 -Hydroxycyclohexyl phenyl ketone ("Irgacure 184" manufactured by Ciba Specialty Chemicals), 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropan-1-one ("Darocur 1116" manufactured by Merck), 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.), isopropylthioxanthone (“Kantacure” manufactured by Word Prekinsop Co., Ltd.) -ITX ") and a mixture of ethyl p-dimethylaminobenzoate, acylphosphine oxide (" Lucirin TPO "manufactured by BASF), and the like. The amount of the photopolymerization initiator used is preferably 10% by mass or less, particularly preferably 0.5 to 5% by mass with respect to the polymerizable liquid crystal compound.

  In addition, as the thermal polymerization initiator used in the thermal polymerization, known ones can be used, for example, methyl acetoacetate peroxide, cumene hydroperoxide, benzoyl peroxide, bis (4-t-butyl). (Cyclohexyl) peroxydicarbonate, t-butyl peroxybenzoate, methyl ethyl ketone peroxide, 1,1-bis (t-hexyl peroxy) 3,3,5-trimethylcyclohexane, p-pentahydroperoxide, Organic peroxides such as t-butyl hydroperoxide, dicumyl peroxide, isobutyl peroxide, di (3-methyl-3-methoxybutyl) peroxydicarbonate, 1,1-bis (t-butylperoxy) cyclohexane Oxide, 2,2'-azobisisobutyronitrile Azonitrile compounds such as 2,2′-azobis (2,4-dimethylvaleronitrile), azoamidin compounds such as 2,2′-azobis (2-methyl-N-phenylpropion-amidin) dihydrochloride, 2,2 ′ Azoamide compounds such as azobis {2-methyl-N- [1,1-bis (hydroxymethyl) -2-hydroxyethyl] propionamide} and alkylazo such as 2,2′azobis (2,4,4-trimethylpentane) Compounds and the like can be used. The amount of the thermal polymerization initiator used is preferably 10% by mass or less, particularly preferably 0.5 to 5% by mass with respect to the polymerizable liquid crystal compound.

(solvent)
Although there is no limitation in particular as a solvent used for the said polymeric liquid crystal composition, the solvent in which the said compound shows favorable solubility is used. For example, aromatic hydrocarbons such as toluene, xylene and mesitylene, ester solvents such as methyl acetate, ethyl acetate and propyl acetate, ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone, tetrahydrofuran, 1,2-dimethoxyethane And ether solvents such as anisole, amide solvents such as N, N-dimethylformamide and N-methyl-2-pyrrolidone, γ-butyrolactone, and chlorobenzene. These can be used alone or in combination of two or more. Moreover, an additive can also be added.

(Polymerization process of polymerizable liquid crystal composition)
The polymerization operation of 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 alignment state of the photo-alignment film comprising the composition for photo-alignment film of the present invention, generally, the light absorption band of the dichroic compound, for example, It is preferable to carry out at a wavelength other than the absorption band of the azobenzene skeleton or anthraquinone skeleton. Such light is specifically ultraviolet light having a wavelength of 320 nm or less, but when the photo-alignment film and the polymerizable liquid crystal composition are decomposed by the ultraviolet light having a wavelength of 320 nm or less, the polymerization treatment is performed with the ultraviolet light having a wavelength of 320 nm or more. In some cases, it is preferable to perform the above.
In order to prevent the orientation of the photo-alignable group already obtained from being disturbed by ultraviolet light of 320 nm or more, usually, light having a light absorption wavelength band different from the light absorption band of the dichroic compound. It is preferable to use a polymerization initiator. Further, a compound that induces a polymerization reaction by absorbing light having a wavelength longer than the absorption band of a normal photopolymerization initiator and causing energy transfer to the polymerization initiator may be mixed. By these, it can superpose | polymerize, without disturbing the orientation state of the composition for photo-alignment films | membranes fixed by photo-alignment operation. On the other hand, if the light for polymerization is irradiated from the same direction as the photo-alignment operation, or if polarized light irradiation having a polarization plane perpendicular to the absorption transition moment of the photo-alignment film molecules is performed, the alignment state of the photo-alignment material may be disturbed. Since there is no, any wavelength can be used.

  In order to quickly complete the polymerization of the polymerizable liquid crystal, degassing or inert gas replacement may be performed before the polymerization. When this operation is performed, the polymerization reaction is greatly accelerated, so even if the wavelength at which the polymerizable liquid crystal is photocured overlaps with the light absorption band of the photo-alignment film molecules, alignment disorder occurs due to re-isomerization of the photo-alignment film molecules. It is possible to complete the photocuring of the polymerizable liquid crystal before. This method is preferably used when wavelength selection for polymerization is limited.

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 starting temperature is the above. It is preferable to use the one in the temperature range.
When the thermal polymerization initiator and the photopolymerization initiator are used in combination, the polymerization temperature and the polymerization temperature are set so that the polymerization speeds of both the photo-alignment film and the polymerizable liquid crystal film are not greatly different together with the limitation of the temperature range. It is preferred to select each initiator. 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.
Further, when the polymerizable liquid crystal composition is heated by polymerization, a combination of an amino resin and a curing agent added to the photo-alignment film layer is prepared so that the heating temperature of the polymerizable liquid crystal composition can be applied. Preferably both layers can be cured at once

  In order to stabilize the solvent resistance and heat resistance of the obtained optical anisotropic body, the optical anisotropic body can be subjected to a heat aging treatment. In this case, it is preferable to heat above the glass transition point of the prepolymerizable liquid crystal film. Usually, 50 to 300 ° C is preferable, 80 to 250 ° C is more preferable, and 100 to 230 ° C is further preferable.

  Hereinafter, the present invention will be described with reference to synthesis examples, examples, and comparative examples, but the present invention is not limited to these examples. Unless otherwise specified, “part” and “%” are based on mass.

(Synthesis Example 1) Synthesis of Dichroic Compound (a) To 8.6 g (25 mmol) of 2,2′-benzidine disulfonic acid, 230 ml of 2% hydrochloric acid was added, and while maintaining the temperature at 0 to 5 ° C., 3.5 g of sodium nitrite ( 51 mmol) was added dropwise little by little and reacted for 2 hours to prepare a diazonium salt. Next, 6.9 g (50 mmol) of salicylic acid was dissolved in 300 ml of 5% aqueous sodium carbonate solution, and the diazonium salt mixture was gradually added dropwise thereto. After reacting for 1 hour, 20% saline was added to obtain a precipitate. This precipitate was recrystallized with a mixed solvent of ethanol and water to obtain 4.8 g of an azo compound represented by the formula (a).

（ａ）

(A)

(Synthesis Example 2) Synthesis of Dichroic Compound (b) To 8.6 g (25 mmol) of 2,2′-benzidine disulfonic acid, 230 ml of 2% hydrochloric acid was added, and while maintaining at 0 to 5 ° C., 3.5 g of sodium nitrite ( 51 mmol) was added dropwise little by little and reacted for 2 hours to prepare a diazonium salt. Next, 8.2 g (50 mmol) of o-trifluoromethylphenol was dissolved in 300 ml of 5% aqueous sodium carbonate solution, and the diazonium salt mixture was gradually added dropwise thereto. After reacting for 4 hours, 20% saline was added to obtain a precipitate. The obtained precipitate was washed with acetone and recrystallized with a mixed solvent of ethanol and ethyl acetate to obtain 7.9 g of an azo compound represented by the formula (b).

（ｂ）

(B)

Synthesis Example 3 Synthesis of Dichroic Compound (c) 4,4′-bis (4-hydroxy-3-trifluoromethylphenyl-1-azo) biphenyl-2,2′-disulfonic acid disodium salt (compound (B)) 2.2 g (0.003 mol) was added to 100 ml of pyridine and stirred. To this, 1.9 g (0.006 mol) of p- (acryloyl-n-hexyloxy) benzoic acid chloride and 0.05 g of hydroquinone were added, and the reaction was continued with stirring at 60 ° C. for 5 hours. The reaction product is cooled, and the precipitate is filtered off, washed with 300 ml of ethanol, and dried in the air to obtain 2.2 g (yield 58%) of the azo compound represented by the formula (c). Obtained.

（ｃ）

(C)

(Preparation of composition for photo-alignment film (1) for example)
2 parts of the compound represented by the formula (a) were dissolved in 98 parts of N-methyl-2-pyrrolidone (NMP) (solution A). Methylated melamine Sumimar M-100C (hereinafter referred to as M-100C) (manufactured by Changchun Artificial Resin. As a hexamethoxymethylated melamine monomer, molecular weight = 390, average polymerization degree is 1.3 to 1.7) 2 parts 98 parts of 2-butoxyethanol (BC) was added to obtain a homogeneous solution (Solution B). 100 parts of solution A, 23 parts of solution B and 77 parts of BC were mixed to prepare a solution having a solid content ratio of 1.0%. The obtained solution was filtered with a 0.45 μm membrane filter to obtain a composition (1) for a photo-alignment film.

(Comparative Example Composition Preparation of Photoalignment Film Composition (2))
2 parts of the compound represented by the formula (a) were dissolved in 98 parts of N-methyl-2-pyrrolidone (NMP) (solution A). 100 parts of solution A and 100 parts of BC were mixed to prepare a solution having a solid content ratio of 1.0%. The obtained solution was filtered with a 0.45 μm membrane filter to obtain a composition (2) for a photo-alignment film.

(Preparation of composition for photo-alignment film (3-22) According to the composition described in the composition composition table for photo-alignment film in Table 1, the photo-alignment film was prepared in the same manner as the preparation of composition for photo-alignment film (1). Compositions (3) to (22) were prepared, and compositions (2), (17), (18), (19), and (20) for photo-alignment films are for comparison.

尚、表中の記号は以下の通りである。
ＢＬ−１：ポリビニルブチラール樹脂エスレック（積水化学製）
ＫＳ−３Ｚ：ポリビニルアセタール樹脂エスレック（積水化学製）
ＢＸ−Ｌ：ポリビニルアセタール樹脂エスレック（積水化学製）
ＢＭ−１：ポリビニルブチラール樹脂エスレック（積水化学製）
ＤＡ−２１２：エポキシアクリレート（ナガセケムテックス製）

The symbols in the table are as follows.
BL-1: Polyvinyl butyral resin ESREC (manufactured by Sekisui Chemical)
KS-3Z: Polyvinyl acetal resin ESREC (manufactured by Sekisui Chemical)
BX-L: Polyvinyl acetal resin ESREC (manufactured by Sekisui Chemical)
BM-1: Polyvinyl butyral resin ESREC (manufactured by Sekisui Chemical)
DA-212: Epoxy acrylate (manufactured by Nagase ChemteX)

（ｄ）

(D)

（e）

(E)

(Preparation of liquid crystal sealant compositions (1) to (3) used for the evaluation of the photo-alignment film)
(Preparation of liquid crystal sealant composition (1))
40 parts of Epicron 1055 (manufactured by Dainippon Ink & Chemicals, Inc.), 20 parts of Epicron 850 (manufactured by Dainippon Ink & Chemicals, Inc.), Phenolite TD-2090 (manufactured by Dainippon Ink & Chemicals, Inc.) 20 parts, 5 parts of silane coupling agent KBM-403 (manufactured by Shin-Etsu Chemical Co., Ltd.), 2 parts of Amicure VDH (manufactured by Ajinomoto Fine Techno Co., Ltd.), 2 parts of N, N-dimethylaminopyridine -It melt | dissolved in 20 parts of (2-methoxyethoxy) ethanol, Furthermore, 10 parts of Leolo seal (made by Tokuyama Co., Ltd.) was added, and the liquid-crystal sealing compound composition (1) was obtained by kneading with a 3 roll mill. .

(Preparation of liquid crystal sealant composition (2))
50 parts of Epicron N-665-EXP (Dainippon Ink Chemical Co., Ltd.), 15 parts of Epicron 830-LVP (Dainippon Ink Chemical Co., Ltd.), Rakkamide TD-971 (Dainippon Ink Chemical Co., Ltd.) 20 parts (contains 25% xylene and 25% 1-butanol), 5 parts silane coupling agent, KBM-403 (manufactured by Shin-Etsu Chemical Co., Ltd.), Amicure VDH (Ajinomoto Fine Techno Co., Ltd.) The liquid crystal sealant composition (2) was obtained by kneading 1 part) and 10 parts Leo Seal (made by Tokuyama Co., Ltd.) with a three roll mill.

(Preparation of liquid crystal sealant composition (3))
Epiklon HP-7200L (Dainippon Ink Chemical Co., Ltd.) 45 parts, Epicron N-740 (Dainippon Ink Chemical Co., Ltd.) 15 parts, Phenolite KA-7052-L2 (Dainippon Ink Chemical) 20 parts by Kogyo Co., Ltd., 5 parts by silane coupling agent KBM-4038 by Shin-Etsu Chemical Co., Ltd., 2 parts by Amicure VDH (by Ajinomoto Fine Techno Co., Ltd.), 2 parts by dicyandiazide It melt | dissolved in 20 parts of monomethyl ether acetate, Furthermore, 10 parts of Leoseal (made by Tokuyama Co., Ltd.) was added, and the liquid-crystal sealing compound composition (3) was obtained by kneading with a 3 roll mill.

(Preparation of polymerizable liquid crystal compositions (LC-1) to (LC-3) used in Examples of optical anisotropic bodies)
(Preparation of Polymerizable Liquid Crystal Composition (LC-1) After dissolving 15 parts of the compound represented by the formula (f) and 15 parts of the compound represented by the formula (g) in 70 parts of xylene, Irgacure 907 (Ciba Specialty Chemicals) 1.2 parts and 0.3 part of an acrylic copolymer represented by formula (h) were added to obtain a solution, which was filtered through a 0.45 μm membrane filter and polymerized. Liquid crystalline composition (LC-1) was obtained, which had a liquid crystal phase-isotropic phase transition temperature of 80 ° C.

Preparation of polymerizable liquid crystal composition (LC-2) 11 parts of compound represented by formula (f), 9 parts of compound represented by formula (g), 16.5 parts of compound represented by formula (i), formula (j ) And 11 parts of the compound represented by formula (k) and 2.5 parts of the compound represented by formula (k) were dissolved in 50 parts of xylene, and then 1.2 parts of Irgacure 907 (manufactured by Ciba Specialty Chemicals Co., Ltd.) ) Was added to obtain 0.3 part of an acrylic copolymer. The obtained solution was filtered with a 0.45 μm membrane filter to obtain a polymerizable liquid crystal composition (LC-2). The liquid crystal phase-isotropic phase transition temperature of (LC-2) is 50 ° C.

Preparation of polymerizable liquid crystal composition (LC-3) After dissolving 39 parts of the compound represented by the formula (l) in 50 parts of xylene, 1.2 parts of Irgacure 907 (manufactured by Ciba Specialty Chemicals Co., Ltd.) 0.3 parts of the acrylic copolymer represented by (h) was added to obtain a solution. The obtained solution was filtered with a 0.45 μm membrane filter to obtain a polymerizable liquid crystal composition (LC-3). The liquid crystal phase-isotropic phase transition temperature of (LC-3) is 111 ° C.

（ｆ）

(F)

（ｇ）

(G)

（ｈ）

(H)

（ｉ）

(I)

（ｊ）

(J)

（ｋ）

(K)

（ｌ）

(L)

(Example of photo-alignment film)
Example 1
The composition for photo-alignment film (1) was applied onto a glass substrate with a spin coater and dried at 100 ° C. for 1 minute. On the surface of the obtained coating film, ultraviolet light having a wavelength of around 365 nm (irradiation intensity: 10 mW / cm ² ) and parallel light are converted into glass through an ultrahigh pressure mercury lamp through a wavelength cut filter and a polarizing filter. Light irradiation was performed at an irradiation energy of 100 mJ / cm ² from the direction perpendicular to the substrate to obtain a photo-alignment film.
Next, a liquid crystal sealant composition (1) containing silica beads having a diameter of 5 μm was applied by a dispenser around the photo-alignment film surface of the obtained glass substrate with a photo-alignment film. After pre-curing this at 80 ° C. for 30 minutes, the glass substrate on which the adhesive is not applied and the alignment surface are overlapped so as to be perpendicular to each other and bonded, and heated at 200 ° C. for 20 minutes to cure the adhesive. Thus, a TN liquid crystal cell was obtained. A suitable amount of a liquid crystal composition for TFT driving (trade name “11-3323”: manufactured by Dainippon Ink & Chemicals, Inc.) was injected under vacuum. The polarizing plates were placed on the upper and lower sides of the obtained TN liquid crystal cell, and the liquid crystal orientation was evaluated by visually observing the external appearance of the TN liquid crystal cell in a crossed Nicol state and a parallel Nicol state (see below).

X: The liquid crystal material is not aligned at all. Δ: The alignment of the liquid crystal material is somewhat observed in alignment defects, and the appearance is partially uneven. The alignment disorder in the vicinity of the sealant is particularly large.
○: The alignment of the liquid crystal material is uniform, but the appearance is partially uneven.
A: The alignment of the liquid crystal material is uniform and there are no defects.

(Examples 2-3)
A TN liquid crystal cell was prepared and evaluated in the same manner as in Example 1 except that the liquid crystal sealant composition was changed. The obtained results are shown in Table 2.

(Comparative Example 1)
A TN liquid crystal cell was prepared and evaluated in the same manner as in Example 1 except that the composition for photo-alignment film (2) was used. The obtained results are shown in Table 2.

(Comparative Examples 2-3)
A TN liquid crystal cell was prepared and evaluated in the same manner as in Comparative Example 1 except that the liquid crystal sealant composition was changed. The obtained results are shown in Table 2.

As a result, the liquid crystal cells obtained in Examples 1 to 3 showed good liquid crystal alignment. It was found that when the liquid crystal cells obtained in Comparative Examples 1 to 3 were used, the liquid crystal alignment was disturbed as a whole. In addition, it was found that the liquid crystal orientation particularly in the vicinity of the sealant was significantly inferior compared with the central part of the liquid crystal cell.
From this, it was confirmed by using the composition for photo-alignment films which added amino resin that the durability with respect to the composition of the high temperature process and sealing member at the time of liquid crystal cell preparation improved.

(Example of optical anisotropic body)
(Evaluation method of orientation)
The orientation of the optical anisotropic body was evaluated in five stages by visual observation and observation with a polarizing microscope.
A: Uniform orientation is obtained visually, and there are no defects even when observed with a polarizing microscope. B: Uniform orientation is obtained visually, but the orientation area is 90 to 100% when observed with a polarizing microscope.
C: Although alignment as much as A and B is not obtained visually, the alignment area in observation with a polarizing microscope is 60 to 90%.
D: Nearly non-oriented by visual observation, but the orientation area by polarizing microscope observation is 40 to 60%.
E: No orientation by visual observation, and orientation area by polarization microscope observation is 40% or less

(Solvent / chemical resistance evaluation method)
The solvent and chemical resistance of the optical anisotropic body was determined by applying NMP / 2-butoxyethanol (BC) (Evaluation 2) as a test solvent on the optical anisotropic body obtained by a spin coater and measuring 1 at 80 ° C. The result of observing the film state when dried for 5 minutes was evaluated in five stages by visual observation and observation with a polarizing microscope.
The test solvent used here is a combination of solvents generally used for the purpose of diluting the alignment film composition.
A: No change in film visually, no defects even with polarization microscope observation B: No change in film visually, but cracks observed in polarization microscope observation C: Partial film peeling off with visual observation However, the occurrence of cracks in the polarizing microscope is the same level as B. D: Most of the film is peeled off visually. E: The whole film is peeled off visually.

  Comparison of optical anisotropic bodies using a polymerizable liquid crystal composition (LC-3) having a high heating temperature for aging treatment was performed in Example 4 and Comparative Example 4.

Example 4
The composition for photo-alignment film (1) was applied onto a glass substrate with a spin coater and dried at 100 ° C. for 1 minute. Next, a linearly polarized and parallel light of visible ultraviolet light (irradiation intensity: 10 mW / cm ² ) near a wavelength of 365 nm is passed through a glass substrate through a wavelength cut filter, a band pass filter, and a polarizing filter to an ultra high pressure mercury lamp. A photo-alignment film was produced by irradiating from the vertical direction. The irradiation amount was 100 mJ / cm ² . After heating at 220 ° C. for 20 minutes, a polymerizable liquid crystal composition (LC-3) was applied on the obtained photo-alignment film with a spin coater and heated at 110 ° C. for 10 minutes to perform an aging treatment, and then nitrogen. Ultraviolet rays were irradiated at 1 J / cm ² in an atmosphere. An optical anisotropic body was obtained. As a result, the orientation was A.

(Comparative Example 4)
An optical anisotropic body was obtained in the same manner as in Example 4 except that the composition for photoalignment film (2) was used instead of the composition for photoalignment film (1) and the composition was not heated at 220 ° C. for 20 minutes. . As a result, the orientation was D, and it was confirmed that the orientation was disturbed.

  Evaluation of orientation, solvent resistance, and chemical resistance was performed in Examples 5 to 30 and Comparative Examples 5 to 17.

(Example 5)
The composition for photo-alignment film (1) was applied onto a glass substrate with a spin coater and dried at 100 ° C. for 1 minute. Next, a linearly polarized and parallel light of visible ultraviolet light (irradiation intensity: 10 mW / cm ² ) near a wavelength of 365 nm is passed through a glass substrate through a wavelength cut filter, a band pass filter, and a polarizing filter to an ultra high pressure mercury lamp. A photo-alignment film was produced by irradiating from the vertical direction. The irradiation amount was 100 mJ / cm ² . A polymerizable liquid crystal composition (LC-1) was applied onto the obtained photo-alignment film with a spin coater, dried at 80 ° C. for 1 minute, and then irradiated with 1 J / cm ² of ultraviolet light in a nitrogen atmosphere. This was heated at 220 ° C. for 20 minutes to obtain an optical anisotropic body. The retardation was 180 nm. The results are shown in Table 3.

(Examples 6-30, Comparative Examples 5-17)
The composition for a photo-alignment film (1) is changed to the composition for a photo-alignment film (2) to (22), and (2) is used in addition to the polymerizable liquid crystal composition (1). Thus, an optical anisotropic body was produced. The irradiation energy is the irradiation energy required for the photo-alignment treatment, and the larger the value, the lower the sensitivity. An irradiation energy of 2000 mJ / cm ² is a range that can sufficiently withstand practical use. The results are shown in Table 3.

As a result, all the compositions for photo-alignment films obtained in Examples 5 to 30 were excellent in solvent resistance and chemical resistance. Example 10 is an example in which the amount of polyvinyl butyral is large, but the sensitivity was slightly lowered. Further, Example 16 is an example using the compound (d) as a dichroic compound, but the sensitivity was slightly lowered as compared with the example using the compound (a).
On the other hand, Comparative Examples 5 to 17 did not have both orientation (sensitivity) and appearance (solvent resistance, chemical resistance).
From the above Examples and Comparative Examples, the composition for photo-alignment film of the present invention can not only produce a highly heat-resistant photo-alignment film, but also a liquid crystal sealant, a dilute solution of polymerizable liquid crystal, and a dilute photo-alignment agent. It has also been revealed that it exhibits excellent solvent resistance and chemical resistance to the liquid. Therefore, the material of the present invention is very useful for the production of an optical element using a liquid crystal display element or an optical anisotropic body.

The heat resistance was evaluated in Example 31 and Comparative Example 18.
(Example 31)
The composition for photo-alignment film (1) was applied onto a glass substrate with a spin coater and dried at 100 ° C. for 1 minute. Next, a linearly polarized light of visible ultraviolet light (irradiation intensity: 10 mW / cm ² ) in the vicinity of a wavelength of 365 nm is converted into a glass substrate through a wavelength cut filter, a bandpass filter, and a polarizing filter through an ultrahigh pressure mercury lamp. Irradiated from the vertical direction. The irradiation amount was 100 mJ / cm ² . The obtained photo-alignment film was kept on a hot plate at 220 ° C. for 20 minutes, and then the polymerizable liquid crystal composition (1) was applied on the photo-alignment film with a spin coater, and the solvent was dried at 80 ° C. for 1 minute. . Thereafter, ultraviolet rays were irradiated at 1 J / cm ^{2 in} a nitrogen atmosphere to obtain a uniform optical anisotropic body. The orientation result was A. The retardation was 185 nm.

(Comparative Example 18)
The composition for photo-alignment film (2) was applied onto a glass substrate with a spin coater and dried at 100 ° C. for 1 minute. Next, a linearly polarized light of visible ultraviolet light (irradiation intensity: 10 mW / cm ² ) in the vicinity of a wavelength of 365 nm is converted into a glass substrate through a wavelength cut filter, a bandpass filter, and a polarizing filter through an ultrahigh pressure mercury lamp. Irradiated from the vertical direction. The irradiation amount was 100 mJ / cm ² . After maintaining the obtained photo-alignment film on a hot plate at 220 ° C. for 20 minutes, the polymerizable liquid crystal composition (1) was applied on the photo-alignment film with a spin coater, and the solvent was dried at 80 ° C. for 1 minute. Thereafter, ultraviolet rays were irradiated at 1 J / cm ² in a nitrogen atmosphere, but a uniform optical anisotropic body could not be obtained. The orientation result was E.

From the results of Example 31 and Comparative Example 17, the composition for photo-alignment films of the present invention maintains the alignment ability even when heated at 220 ° C. for 20 minutes after performing light irradiation for alignment treatment. However, in the case of a system not containing an amino resin, the orientation ability was lost after heating at 220 ° C. for 20 minutes.
From this result, it can be determined that the heat resistance of the photo-alignment film has been improved.

Claims (10)

A composition for a photo-alignment film, comprising a dichroic compound and an amino resin. The composition for photo-alignment films according to claim 1, wherein the dichroic compound is an azo compound. The composition for photo-alignment films according to claim 1, wherein the dichroic compound is an azo compound represented by the general formula (1).

In the formula, R ¹ and R ² are each independently a hydroxy group or an amino group, a carboxyl group, a (meth) acryloyl group, a (meth) acryloyloxy group, a (meth) acrylamide group, a vinyl group, a vinyloxy group, and It represents a polymerizable functional group selected from the group consisting of maleimide groups.
X ¹ represents a single bond when R ¹ is a hydroxy group, amino group, or carboxyl group, and represents a linking group represented by — (A ¹ -B ¹ ) _m — when R ¹ is a polymerizable functional group. Represent,
X ² represents a single bond when R ² is a hydroxy group, an amino group or a carboxyl group, and when R ² is a polymerizable functional group, X ² represents a linking group represented by-(A ² -B ² ) _n- To express. 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—, — It represents O—CO—, —CO—NH—, —NH—CO—, —NH—CO—O—, or —O—CO—NH—. m and n each independently represents an integer of 0 to 4. However ^{A 1} is bonded to ^{R 1, A 2} binds to ^{R 2.}
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. R ³ and R ⁴ each independently represent a hydrogen atom, a halogen atom, a carboxy group, a halogenated methyl group, a halogenated methoxy group, a cyano group or a hydroxyl group, —OR ⁷ (wherein R ⁷ has 2 to 2 carbon atoms, 6 represents an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, or a lower alkoxy group having 1 to 6 carbon atoms. However, the carboxy group may form a salt with an alkali metal.
R ⁵ and R ⁶ each independently represent a carboxyl group, a sulfo group, a nitro group, an amino group, a carbamoyl group, an alkoxycarbonyl group, or a hydroxy group. However, the carboxy group and the sulfo group may form a salt with the alkali metal. Y represents a single bond, —C═C—, or —C≡C—. The composition for photo-alignment film according to claim 1, wherein the amino resin is a melamine resin. The melamine resin has a mononuclear ratio of 50% by weight or more, an average condensation degree of 6 or less, a weight average molecular weight of 3000 or less, and methylol etherified with methanol, n-butanol, or isobutanol. The composition for photo-alignment films according to claim 4, which is a low molecular weight melamine resin having an average number of groups of 2.5 or more per triazine ring. In the manufacturing method of the photo-alignment film | membrane which irradiates the light which has anisotropy to this coating film after apply | coating the composition for photo-alignment films | membrane of Claim 1 on a board | substrate, it heats after irradiating light. The manufacturing method of the photo-alignment film | membrane characterized by these. An optical anisotropic body obtained by applying a polymerizable liquid crystal composition on a photo-alignment film using the composition for photo-alignment film according to claim 1 and polymerizing the composition in an aligned state. The process 1 which apply | coats the composition for photo-alignment films | membrane of Claim 1 on a board | substrate, the process 2 which irradiates the light which has anisotropy to this coating film, and apply | coated the polymerizable liquid crystal composition and orientated it. The method for producing an optical anisotropic body according to claim 7, wherein the step 3 of polymerizing in a state is performed in this order, the step of curing the amino resin between after the step 1 and after the step 3. A method for producing an optical anisotropic body, comprising: An optical element using the optical anisotropic body according to claim 7. The process 1 which apply | coats the composition for photo-alignment films | membrane of Claim 1 on a board | substrate, the process 2 which irradiates the light which has anisotropy to this coating film, and apply | coated the polymerizable liquid crystal composition and orientated it. It is the manufacturing method of the optical element of Claim 9, Comprising: The process 3 which obtains the optical anisotropic body superposed | polymerized in a state, and the process 4 which obtains the optical element which installed the said optical anisotropic body are performed in this order, Comprising: The said process A method for producing an optical element, comprising the step of curing the amino resin after step 1 and between step 4.