JP2017068019A - Heat curable composition having optical alignment property, alignment layer, substrate with alignment layer and manufacturing method of the same, and phase difference plate and manufacturing method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat curable composition that has good liquid crystal alignment capability, can form an alignment layer having excellent adhesion with a liquid crystal layer, and has an optical alignment property, and an alignment layer using the same, a substrate with an alignment layer, and a phase difference plate.SOLUTION: The present invention provides a heat curable composition having an optical alignment property, and containing: a copolymer that includes an optical alignment property constitutional unit and heat crosslinking constitutional unit; a crosslinking agent that couples with a heat crosslinking group of the heat crosslinking constitutional unit; and a compound that includes at least one of a hydroxy group and a carboxy group, an aromatic hydrocarbon group, and an ethylenically unsaturated double bond group.SELECTED DRAWING: None

Description

  The present invention relates to a thermosetting composition having photo-alignment used for an alignment layer, an alignment layer, a substrate with an alignment layer and a method for producing the same, a retardation plate and a method for producing the same.

  In addition to liquid crystal display elements, liquid crystals are used in various optical elements such as retardation plates and polarizing plates by utilizing their orientation and anisotropy of physical properties such as refractive index, dielectric constant, and magnetic susceptibility. Applications are being studied.

  An alignment layer is used to align the liquid crystal. As a method for forming the alignment layer, for example, a rubbing method or a photo-alignment method is known. The photo-alignment method does not generate static electricity or dust, which is a problem of the rubbing method, and can control the alignment process quantitatively. (For example, refer to Patent Document 1).

  In addition to the liquid crystal alignment ability, the alignment layer is required to have heat resistance, solvent resistance, and the like. For example, the alignment layer may be exposed to heat or a solvent during the manufacturing process of various devices, or may be exposed to a high temperature when the various devices are used. When the alignment layer is exposed to a high temperature, the liquid crystal alignment ability may be significantly reduced.

  Therefore, for example, in Patent Document 2, in order to obtain stable liquid crystal alignment ability, a liquid crystal aligning agent containing a polymer component having a structure capable of crosslinking reaction by light and a structure crosslinked by heat, and light. A liquid crystal aligning agent containing a polymer component having a structure capable of crosslinking reaction and a compound having a structure crosslinked by heat has been proposed.

  Patent Document 3 discloses (A) an acrylic copolymer having a photodimerization site and a thermal crosslinking site in order to obtain excellent liquid crystal alignment ability, sufficient heat resistance, high solvent resistance and high transparency; (B) The thermosetting film formation composition which has a photo-alignment property containing a crosslinking agent is proposed. (B) The cross-linking agent binds to the thermal cross-linking site of (A) the acrylic copolymer, and the thermosetting film-forming composition having photo-alignment properties is cured by heating to form a cured film. An alignment layer can be formed by irradiation with polarized ultraviolet rays.

  In Patent Document 4, in order to obtain excellent liquid crystal alignment ability, sufficient heat resistance, high solvent resistance and high transparency, (A) an acrylic copolymer having a photodimerization site and a thermal crosslinking site, and (B ) A photo-alignment property comprising an acrylic polymer having at least one of a predetermined alkyl ester group and a hydroxyalkyl ester group and at least one of a carboxyl group and a phenolic hydroxy group, and (C) a crosslinking agent. A thermosetting film-forming composition having been proposed. (C) The crosslinking agent is a thermosetting film-forming composition having a photo-alignment property, which is bonded to (A) the thermal crosslinking site of the acrylic copolymer and (B) the carboxyl group and the phenolic hydroxy group of the acrylic polymer. Can be cured by heating to form a cured film, and the cured film can be irradiated with polarized ultraviolet rays to form an alignment layer.

  Patent Document 5 discloses (A) a compound having a photo-alignment group and a hydroxy group, and (B) a hydroxy group in order to obtain excellent liquid crystal alignment ability, sufficient heat resistance, high solvent resistance and high transparency. And a thermosetting film-forming composition having photo-alignment properties, which contains a polymer having at least one of carboxyl groups and (C) a crosslinking agent. (C) The crosslinking agent is bonded to the hydroxy group of the compound (A) and the hydroxy group and carboxyl group of the polymer (B), and is cured by heating the thermosetting film-forming composition having photo-alignment properties. And an alignment layer can be formed by irradiating the cured film with polarized ultraviolet rays.

  However, when thermosetting is performed, the hardness of the alignment layer is increased, and there is a problem in that the adhesion with the liquid crystal layer formed on the alignment layer may be reduced. In particular, as in Patent Documents 3 and 4, when an acrylic copolymer having a photo-alignment site and a thermal cross-linking site is used and thermosetting is performed with a cross-linking agent, a network structure is formed inside the film. Thus, the adhesion between the alignment layer and the liquid crystal layer formed thereon is lowered.

  In view of the above problems, the present inventors can form an alignment layer that is excellent in liquid crystal alignment ability and adhesion with a liquid crystal layer, and as a thermosetting composition having photoalignment, a photoalignment structure including a styrene skeleton. A thermosetting composition containing a copolymer having a unit and a thermally crosslinkable structural unit containing a styrene skeleton is disclosed (Patent Document 6).

  On the other hand, Patent Document 7 includes (A) a compound having a photoalignable group and a photoalignable group as a cured film that can be used as an alignment material having excellent adhesion to the substrate while using an acrylic film substrate. A cured film formed of a cured film forming composition containing at least one selected from the group consisting of polymers and (B) a polymer having an acrylate unit structure has been proposed. Patent Document 7 describes a compound having a hydroxy group and a (meth) acryl group as an adhesion improving component. However, the adhesion evaluation of Examples 6 to 10 in which the adhesion improving component is used in Patent Document 7 is the same evaluation result as other examples in which the adhesion improving component is not used. It is shown.

Japanese Patent No. 40947644 Japanese Patent No. 4207430 International Publication No. 2010/150748 International Publication No. 2011/010635 International Publication No. 2011/126022 Japanese Patent No. 5626492 International Publication No. 2014/073658

  In recent years, more durability has been demanded for various optical elements such as retardation plates and polarizing plates, and the adhesion between the alignment layer and the liquid crystal layer used in these has also been demanded, and improved adhesion. Sex is desired.

  The present invention has been made in view of the above problems, and in a thermosetting composition containing a copolymer having both a photo-alignment site and a thermal cross-linking site, it has a good liquid crystal alignment capability, and a liquid crystal It is a main object to provide a thermosetting composition having photo-alignment property, an alignment layer, a substrate with an alignment layer, and a retardation plate, which can form an alignment layer having excellent adhesion to the layer, and having photo-alignment properties.

  In addition to the copolymer having a photo-alignable structural unit and a heat-crosslinkable structural unit, and a crosslinking agent that binds to the heat-crosslinkable group of the heat-crosslinkable structural unit, the present inventors have added a hydroxy group and a carboxy group. When a compound having at least one of the following, an aromatic hydrocarbon group and an ethylenically unsaturated double bond group is contained, the liquid crystal alignment ability is not hindered and the liquid crystal layer has a good liquid crystal alignment ability. The inventors have found that an alignment layer with better adhesion can be obtained, and have reached the present invention.

The present invention includes a copolymer having a photo-alignable structural unit and a thermally crosslinkable structural unit;
A crosslinking agent that binds to the thermally crosslinkable group of the thermally crosslinkable structural unit;
A compound having at least one of a hydroxy group and a carboxy group, an aromatic hydrocarbon group, and an ethylenically unsaturated double bond group;
A thermosetting composition having photo-alignment characteristics, comprising:

  It is preferable that the thermosetting composition having photo-alignment property of the present invention further contains a photoinitiator because an alignment layer having better adhesion to the liquid crystal layer can be obtained.

  Moreover, in this invention, it is preferable from the point of the more excellent liquid crystal aligning capability and the more excellent adhesiveness that the said photo-alignment structural unit contains the photo-alignment structural unit represented by following formula (1).

(Wherein, in formula (1), X is a photo-alignment group, L ¹ is a divalent linking group or single bond, R ¹ is a hydrogen atom, methyl group, chlorine atom or phenyl group, k is 1-5. Represents.)

The present invention also provides a photodimerization structure or photoisomerization structure of a photoalignable group possessed by a photoalignable structural unit, and a crosslinked structure formed by bonding a thermally crosslinkable group possessed by a thermally crosslinkable structural unit and a crosslinking agent. A copolymer having
A compound having a crosslinked structure formed by bonding at least one of a hydroxy group and a carboxy group and a crosslinking agent, an aromatic hydrocarbon group, and an ethylenically unsaturated double bond group;
An alignment layer characterized by containing is provided.

  Furthermore, the present invention provides a substrate with an alignment layer, characterized by comprising a substrate and the alignment layer described above formed on the substrate.

Moreover, this invention apply | coats the thermosetting composition which has the photo-orientation property which concerns on the said invention on a board | substrate, forms the coating film of the said thermosetting composition which has the said photo-orientation property, Forming a cured film by heating; and
And a step of forming an alignment layer by irradiating the cured film with polarized ultraviolet rays.

The present invention also includes a substrate,
A photo-dimerization structure or photo-isomerization structure of a photo-alignment group of a photo-alignment constituent unit, and a heat-crosslinkable group of a heat-cross-linkable constitution unit and a cross-linking agent, which are arranged on the substrate, are combined. It has a structure in which a copolymer having a crosslinked structure, a crosslinked structure formed by bonding at least one of a hydroxy group and a carboxy group and a crosslinking agent, an aromatic hydrocarbon group, and an ethylenically unsaturated double bond group are polymerized. An alignment layer containing a compound;
A retardation layer having a structure in which an ethylenically unsaturated double bond group of the polymerizable liquid crystal composition having an ethylenically unsaturated double bond group disposed on the alignment layer is polymerized. A retardation plate is provided.

Moreover, this invention apply | coats the thermosetting composition which has the photo-orientation property which concerns on the said invention on a board | substrate, forms the coating film of the said thermosetting composition which has the said photo-orientation property, Forming a cured film by heating; and
Forming an alignment layer by irradiating the cured film with polarized ultraviolet rays;
On the alignment layer, a polymerizable liquid crystal composition having an ethylenically unsaturated double bond group is applied to form a coating film of the polymerizable liquid crystal composition, and the coating film is a phase of the polymerizable liquid crystal composition. Aligning liquid crystal molecules with the alignment layer by heating to a transition temperature;
And a step of forming a retardation layer by irradiating light onto a coating film of a polymerizable liquid crystal composition in which the liquid crystal molecules are aligned.

  In the present invention, a thermosetting composition having photoalignment capable of forming an alignment layer having excellent liquid crystal alignment ability and adhesion to the liquid crystal layer, and alignment using the thermosetting composition having the photoalignment. There is an effect that it is possible to provide a layer, a substrate with an alignment layer and a manufacturing method thereof, and a retardation plate and a manufacturing method thereof.

It is a schematic sectional drawing which shows an example of the board | substrate with an alignment layer of this invention. It is a schematic sectional drawing which shows an example of the phase difference plate of this invention.

  Hereinafter, the thermosetting composition having photo-alignment property of the present invention, an alignment layer using the same, a substrate with an alignment layer and a manufacturing method thereof, a retardation plate and a manufacturing method thereof will be described in detail.

A. Thermosetting composition having photo-orientation The thermosetting composition having photo-orientation of the present invention comprises a copolymer having a photo-orienting constitutional unit and a heat-crosslinking constitutional unit,
A crosslinking agent that binds to the thermally crosslinkable group of the thermally crosslinkable structural unit;
A compound having at least one of a hydroxy group and a carboxy group, an aromatic hydrocarbon group, and an ethylenically unsaturated double bond group;
It is characterized by containing.

In the present invention, in addition to the copolymer having a photo-alignable structural unit and a heat-crosslinkable structural unit, and a crosslinking agent that binds to the heat-crosslinkable group of the heat-crosslinkable structural unit, Thermally crosslinkable polymerizable compound having at least one aromatic hydrocarbon group and ethylenically unsaturated double bond group (hereinafter simply referred to as “thermally crosslinkable polymerizable compound containing an aromatic hydrocarbon group”, “the heat It may be referred to as a “crosslinkable polymerizable compound”). Since the thermally crosslinkable polymerizable compound containing the aromatic hydrocarbon group is a low molecular component compared to the polymer, the alignment layer is formed using the thermosetting composition having photo-alignment property of the present invention. In such a case, the thermally crosslinkable polymerizable compound tends to emerge on the surface of the alignment layer. Therefore, the thermally crosslinkable polymerizable compound containing the aromatic hydrocarbon group can be localized near the surface of the alignment layer. When thermosetting is performed in this state, an aromatic hydrocarbon group, an ethylenically unsaturated double bond group, and at least one of a hydroxy group and a carboxy group of the thermally crosslinkable polymerizable compound reacts with the crosslinker. A polymerizable compound containing can be immobilized in the vicinity of the surface of the alignment layer. Furthermore, when forming a liquid crystal layer such as a retardation layer containing a cured product of the polymerizable liquid crystal composition on the alignment layer, the ethylenically unsaturated double of the polymerizable compound fixed in the vicinity of the surface of the alignment layer. The bonding group is capable of reacting with an ethylenically unsaturated double bond group included in the polymerizable liquid crystal compound contained in the polymerizable liquid crystal composition. Therefore, at the interface between the alignment layer and the liquid crystal layer, the ethylenically unsaturated double bond group of the polymerizable compound immobilized in the vicinity of the surface of the alignment layer and the ethylenically unsaturated divalent group of the polymerizable liquid crystal compound used in the liquid crystal layer. A heavy bond group can be reacted and adhesion between the alignment layer and the liquid crystal layer can be improved.
As shown in the comparative example described later, when a thermally crosslinkable polymerizable compound containing only an aliphatic hydrocarbon group and not containing an aromatic hydrocarbon group as a hydrocarbon group is used, adhesion is not improved. There was a tendency for the liquid crystal alignment ability to be easily inhibited. On the other hand, in the present invention, since a thermally crosslinkable polymerizable compound containing an aromatic hydrocarbon group is used, the liquid crystal alignment ability is not hindered, and the liquid crystal layer has good liquid crystal alignment ability and adhesion to the liquid crystal layer. An alignment layer that is more excellent is obtained. The thermally crosslinkable polymerizable compound containing an aromatic hydrocarbon group is less likely to inhibit the liquid crystal alignment ability even when it exists at the interface with the liquid crystal layer as compared with the case containing only an aliphatic hydrocarbon group, and When present at the interface, the interaction between the liquid crystal molecules and the π-electron system is strengthened, the reaction with the ethylenically unsaturated double bond group of the polymerizable liquid crystal compound is more likely to proceed, and the adhesion to the liquid crystal layer is further improved. Estimated to become better.

  Moreover, according to the thermosetting composition having photo-alignment property of the present invention, since it contains a copolymer having both a photo-alignment site and a thermal cross-linking site, and a cross-linking agent, Depending on the structure, the alignment layer has good heat resistance and solvent resistance, and an alignment layer with high durability can be obtained. An alignment layer containing a copolymer having both a photo-alignment site and a thermal cross-linking site and a cross-linking agent has high hardness, and thus the adhesion to the liquid crystal layer formed thereon tends to be lowered. There is. On the other hand, in the present invention, since the thermally crosslinkable polymerizable compound containing an aromatic hydrocarbon group is further used in combination, it is possible to obtain highly durable adhesiveness.

Hereinafter, each component in the thermosetting composition having the photo-alignment property of the present invention will be described.
1. Copolymer The copolymer used in the present invention has a photo-alignment structural unit and a thermally crosslinkable structural unit.
Hereinafter, each structural unit in the copolymer will be described.

(1) Photoalignment structural unit The photoalignment structural unit in this invention is a site | part which expresses anisotropy by producing a photoreaction by light irradiation. The photoreaction is preferably a photodimerization reaction or a photoisomerization reaction. That is, the photo-alignment structural unit is a photodimerization structural unit that develops anisotropy by generating a photodimerization reaction by light irradiation, or a light that exhibits anisotropy by generating a photoisomerization reaction by light irradiation. An isomerized structural unit is preferred.

  A photo-alignment structural unit has a photo-alignment group. As described above, the photo-alignment group is a functional group that exhibits anisotropy by causing a photoreaction by light irradiation, and is preferably a functional group that causes a photodimerization reaction or a photoisomerization reaction.

  Examples of the photoalignable group that causes a photodimerization reaction include a cinnamoyl group, a chalcone group, a coumarin group, an anthracene group, a quinoline group, an azobenzene group, and a stilbene group. The benzene ring in these functional groups may have a substituent. Any substituent that does not interfere with the photodimerization reaction may be used, and examples thereof include an alkyl group, an aryl group, a cycloalkyl group, an alkoxy group, a hydroxy group, a halogen atom, a trifluoromethyl group, and a cyano group.

  The photo-alignment group that causes a photoisomerization reaction is preferably one that causes a cis-trans isomerization reaction, and examples thereof include a cinnamoyl group, a chalcone group, an azobenzene group, and a stilbene group. The benzene ring in these functional groups may have a substituent. Any substituent that does not interfere with the photoisomerization reaction may be used, and examples thereof include an alkoxy group, an alkyl group, a halogen atom, a trifluoromethyl group, and a cyano group.

  Among these, the photo-alignment group is preferably a cinnamoyl group. Specifically, the cinnamoyl group is preferably at least one selected from the group consisting of groups represented by the following formulas (2-1) and (2-2).

In the above formula ^{(2-1), R 11} represents a hydrogen atom, an alkyl group having 1 to 18 carbon atoms, an aryl group or a cycloalkyl group having 1 to 18 carbon atoms having 1 to 18 carbon atoms. However, the alkyl group, aryl group and cycloalkyl group may be bonded via an ether bond, ester bond, amide bond or urea bond, and may have a substituent. R ^{12 to} R ¹⁵ are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 18 carbon atoms, an aryl group having 1 to 18 carbon atoms, a cycloalkyl group having 1 to 18 carbon atoms, or an alkyl group having 1 to 18 carbon atoms. Represents an alkoxy group or a cyano group. However, the alkyl group, aryl group and cycloalkyl group may be bonded via an ether bond, ester bond, amide bond or urea bond, and may have a substituent. R ¹⁶ and R ¹⁷ each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 18 carbon atoms, an aryl group having 1 to 18 carbon atoms, or an alkoxy group having 1 to 18 carbon atoms.
Further, in the above formula ^{(2-2), R} 21 ~R ²⁵ independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 18 carbon atoms, 1 to 18 aryl group or a carbon of 1 to 18 carbon atoms A cycloalkyl group, an alkoxy group having 1 to 18 carbon atoms, or a cyano group. However, the alkyl group, aryl group and cycloalkyl group may be bonded via an ether bond, ester bond, amide bond or urea bond, and may have a substituent. R ²⁶ and R ²⁷ each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 18 carbon atoms, an aryl group having 1 to 18 carbon atoms, or an alkoxy group having 1 to 18 carbon atoms.

  In the case where the photo-alignment group is a cinnamoyl group and the group is represented by the above formula (2-1), the benzene ring of the styrene skeleton contained in the monomer unit described later is a benzene ring of the cinnamoyl group. It may be.

  Further, the cinnamoyl group represented by the above formula (2-1) is more preferably a group represented by the following formula (2-3).

In the above formula (2-3), R ^{12 to} R ¹⁷ are the same as in the above formula (2-1). R ¹⁸ represents a hydrogen atom, an alkoxy group having 1 to 18 carbon atoms, a cyano group, an alkyl group having 1 to 18 carbon atoms, a phenyl group, a biphenyl group, or a cyclohexyl group. However, the alkyl group, phenyl group, biphenyl group and cyclohexyl group may be bonded via an ether bond, an ester bond, an amide bond or a urea bond. n represents 1 to 5, and R ¹⁸ may be bonded to any of the ortho, meta, and para positions. When n is 2 to 5, R ¹⁸ may be the same as or different from each other. Among them, it is preferable that n is 1 and R ¹⁸ is bonded to the para position.

  When the photoalignable group is at least one group selected from the group consisting of the groups represented by the above formulas (2-3) and (2-2), an aromatic ring is provided near the end of the photoalignable structural unit. Are arranged, and contain a lot of π electrons. Therefore, it is considered that the affinity with the liquid crystal layer formed on the alignment layer is increased, the liquid crystal alignment ability is improved, and the adhesion with the liquid crystal layer is increased.

  Examples of the monomer unit constituting the photoalignable structural unit include acrylic acid ester, methacrylic acid ester, styrene, acrylamide, methacrylamide, maleimide, vinyl ether, and vinyl ester. Of these, acrylic acid esters, methacrylic acid esters, and styrene are preferred as in the case of the thermally crosslinkable structural unit.

  As a photo-alignment structural unit, the structural unit represented by following formula (3) can be illustrated.

(In the above formula (3), Z ¹ represents a monomer unit, X represents a photo-alignment group, and L ¹ represents a divalent linking group or a single bond.)

In the above formula (3), Z ¹ represents a monomer unit, and examples thereof include acrylic acid ester, methacrylic acid ester, styrene, acrylamide, methacrylamide, maleimide, vinyl ether, and vinyl ester. Among these, as described above, acrylic acid ester, methacrylic acid ester, and styrene are preferable. Specific examples include monomer units represented by the following formulas (4-1) to (4-6).

(In the above formulas (4-1) to (4-6), R ³¹ represents a hydrogen atom, a methyl group, a chlorine atom or a phenyl group, R ³² represents a hydrogen atom or a methyl group, R ³³ represents a hydrogen atom, (A methyl group, a chlorine atom or a phenyl group, R ³⁴ represents a hydrogen atom or a lower alkyl group.)

When the monomer unit is styrene, -L ¹ -X may be bonded to any of the ortho, meta, and para positions, or a plurality of bonds may be bonded. That is, it is preferable that the photo-alignment structural unit represented by the following formula (1) is included from the viewpoint of more excellent liquid crystal alignment ability and better adhesion. In general, many liquid crystal molecules have an aromatic ring such as a benzene ring, and also include a π electron system. Therefore, when the copolymer has a styrene skeleton and contains a lot of π-electron systems, the alignment layer formed from the thermosetting composition having the photo-alignment property of the present invention has a strong interaction with liquid crystal molecules. Become. Thereby, it becomes easy to control alignment of liquid crystal molecules, and it is considered that excellent liquid crystal alignment ability can be obtained. Moreover, it is considered that the alignment layer formed from the thermosetting composition having the photo-alignment property of the present invention has high adhesion to the liquid crystal layer formed on the alignment layer due to the interaction of the π electron system. .

(Wherein, in formula (1), X is a photo-alignment group, L ¹ is a divalent linking group or single bond, R ¹ is a hydrogen atom, methyl group, chlorine atom or phenyl group, k is 1-5. Represents.)

k is 1 to 5, and -L ¹ -X may be bonded to any of the ortho, meta, and para positions. When k is 2 to 5, L ¹ and X may be the same as or different from each other. Among them, it is preferable that k is 1 and -L ¹ -X is bonded to the para position.

In the above formula (3), X represents a photo-alignment group, and examples thereof include a cinnamoyl group, a chalcone group, a coumarin group, an anthracene group, a quinoline group, an azobenzene group, and a stilbene group. The benzene ring in these functional groups may have a substituent. The substituent may be any as long as it does not interfere with the photodimerization reaction or the photoisomerization reaction. For example, an alkyl group, aryl group, cycloalkyl group, alkoxy group, hydroxy group, halogen atom, trifluoromethyl group, cyano group, etc. Is mentioned.
Among these, the photoalignment group is preferably a cinnamoyl group. Specifically, the groups represented by the above formulas (2-1) and (2-2) are preferable.

L ¹ in the above formula (3) is a divalent linking group or a single bond. When L ¹ is a single bond, the photoalignable group X is directly bonded to the monomer unit Z ¹ . Examples of the divalent linking group include an ether bond, a thioether bond, an ester bond, a thioester bond, a carbonyl bond, a thiocarbonyl bond, an alkylene group, an arylene group, a cycloalkylene group, and combinations thereof. Specifically, —O—, —S—, —COO—, —COS—, —CO—, —OCO—, —OCO (CH ₂ ) _n COO—, —OCO (CH ₂ CH ₂ O) _m COO _{-, - OCOC 6 H 4 O} -, - OCOC 6 H 10 O -, - COO (CH 2) n O -, - COO (CH 2 CH 2 O) m -, - COOC 6 H 4 O -, - COOC ₆ H ₁₀ O—, —O (CH ₂ ) _n O—, —O (CH ₂ CH ₂ O) _m —, —OC ₆ H ₄ O—, —OC ₆ H ₁₀ O—, — (CH ₂ ) _n O- etc. are mentioned. n is 1-20, m is 1-10.

The photo-alignment structural unit possessed by the copolymer may be one type or two or more types.
For the synthesis of the copolymer, a monomer having a photoalignable group that forms the photoalignable structural unit can be used. The monomer which has a photo-alignment group can be used individually or in combination of 2 or more types.

  As a content rate of the photo-alignment structural unit in a copolymer, when the whole copolymer is 100 mol%, it can set within the range of 10 mol%-90 mol%, Preferably it is 20 mol%- It is in the range of 80 mol%. When the content ratio of the photo-alignment structural unit is small, the sensitivity is lowered, and it may be difficult to impart good liquid crystal alignment ability. In addition, when the content ratio of the photo-alignable structural unit is large, the content ratio of the heat-crosslinkable structural unit is relatively small, sufficient thermosetting property cannot be obtained, and it is difficult to maintain good liquid crystal alignment ability. It may become.

(2) Thermally crosslinkable structural unit The thermally crosslinkable structural unit in this invention is a site | part couple | bonded with a crosslinking agent by heating.
The thermally crosslinkable structural unit has a thermally crosslinkable group. Examples of the thermally crosslinkable group include a hydroxy group, a carboxy group, a phenolic hydroxy group, a mercapto group, a glycidyl group, and an amide group. Among these, from the viewpoint of reactivity, an aliphatic hydroxy group is preferable, and a primary hydroxy group is more preferable. The primary hydroxy group refers to a hydroxy group in which the carbon atom to which the hydroxy group is bonded is a primary carbon atom.

Examples of the monomer unit constituting the thermally crosslinkable structural unit include acrylic acid ester, methacrylic acid ester, styrene, acrylamide, methacrylamide, maleimide, vinyl ether, vinyl ester and the like. Of these, acrylic acid esters, methacrylic acid esters, and styrene are preferable.
Acrylic acid ester and methacrylic acid ester monomers have the advantages of high solubility, easy availability as commercial products, and good reactivity when copolymerized.
In the case of styrene, it is preferable from the viewpoint of more excellent liquid crystal alignment ability and better adhesion. By having a styrene skeleton in the copolymer, a copolymer containing a large number of π electron systems can be obtained. Therefore, when the alignment layer is formed using the thermosetting composition having the photo-alignment property of the present invention, the liquid crystal alignment ability is improved and the adhesion with the liquid crystal layer is improved by the interaction of π electrons. It is thought that you can.

  As the thermally crosslinkable structural unit, a structural unit represented by the following formula (5) can be exemplified.

(In the above formula (5), Z ² represents a monomer unit, Y represents a thermally crosslinkable group, and L ² represents a divalent linking group or a single bond.)

In the above formula (5), Z ² represents a monomer unit, and examples thereof include acrylic acid ester, methacrylic acid ester, acrylamide, methacrylamide, styrene, maleimide, vinyl ether, vinyl ester and the like. Among these, as described above, acrylic acid ester, methacrylic acid ester, and styrene are preferable.
Specific examples of the monomer unit include monomer units represented by the formulas (4-1) to (4-6).

When the monomer unit is styrene as represented by the formula (4-2), -L ² -Y may be bonded to any of the ortho, meta, and para positions, and a plurality of bonds may be bonded. It may be. In a plurality, L ² and Y may be the same as or different from each other. Among them, it is preferable that one -L ² —Y is bonded to the para position.

  In the above formula (5), Y represents a thermally crosslinkable group, and examples thereof include a hydroxy group, a carboxy group, a phenolic hydroxy group, a mercapto group, a glycidyl group, and an amide group. Among them, as described above, from the viewpoint of reactivity, an aliphatic hydroxy group is preferable, and a primary hydroxy group is more preferable.

In the above formula (5), L ² represents a single bond or a divalent linking group. When L ² is a single bond, the thermally crosslinkable group Y is directly bonded to the monomer unit Z ² . Examples of the divalent linking group include an ether bond, a thioether bond, an ester bond, a thioester bond, a carbonyl bond, a thiocarbonyl bond, an alkylene group, an arylene group, a cycloalkylene group, and combinations thereof. Among these, a divalent linking group is, - _{(CH 2) n} - or _{- (C 2 H 4 O)} m - preferably has a, n represents 4 to 11, m is preferably 2-5. If n and m are too small, the distance between the heat-crosslinkable group and the main skeleton of the copolymer in the heat-crosslinkable structural unit is shortened, so that it becomes difficult for the cross-linking agent to bind to the heat-crosslinkable group. There is a possibility that the reactivity between the unit and the cross-linking agent may decrease. On the other hand, if n and m are too large, the chain length of the linking group in the heat-crosslinkable structural unit becomes long, so that the terminal heat-crosslinkable group is unlikely to appear on the surface, and the crosslinker is less likely to bind to the heat-crosslinkable group. The reactivity between the thermally crosslinkable structural unit and the crosslinking agent may be reduced.

For example, when L ² is — (C ₂ H ₄ O) _m — and Y is a hydroxy group, —L ² —Y may be — (C ₂ H ₄ O) _m —H. it can.

In the above formula (5), the thermally crosslinkable group Y is bonded to the monomer unit Z ² via a divalent linking group or a single bond L ^{2. When} Y is a carboxy group or a hydroxy group, The thermally crosslinkable structural unit represented by the above formula (5) may be a structural unit represented by the following formula (5-1) or formula (5-2). In the following formula, each symbol is the same as the above formula.

The thermally crosslinkable structural unit may have a crosslinking group. In this case, the thermally crosslinkable structural unit can also serve as a crosslinking agent. When using the copolymer which has such a heat-crosslinkable structural unit, the thermosetting composition which has the photo-alignment property of this invention can be utilized without adding a crosslinking agent. However, from the viewpoint of storage stability, the thermally crosslinkable structural unit preferably has no crosslinkable group.
Examples of the thermally crosslinkable structural unit having a crosslinking group include those having a phenolic hydroxy group or glycidyl group in which the ortho position is substituted with a hydroxymethyl group or an alkoxymethyl group.

  Examples of the monomer that forms such a thermally crosslinkable structural unit include acrylic acid ester compounds, methacrylic acid ester compounds, acrylamide compounds, methacrylamide compounds, styrene compounds, maleimide compounds, and vinyl compounds.

  Examples of the acrylic ester compound and methacrylic ester compound include 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 3-hydroxypropyl acrylate, 3-hydroxypropyl methacrylate, 4-hydroxybutyl acrylate, 4-hydroxybutyl methacrylate, 2,3-dihydroxypropyl acrylate, 2,3-dihydroxypropyl methacrylate, diethylene glycol monoacrylate, diethylene glycol monomethacrylate, triethylene glycol monoacrylate, tetraethylene glycol monoacrylate, dipropylene glycol monoacrylate, tripropylene glycol monoacrylate, tetrapropylene Hides such as glycol monoacrylate Monomers having a carboxy group and an acrylic group or methacrylic group.

Examples of the styrene compound include esterified products of 4-vinylbenzoic acid and diol, esterified products of 4-vinylbenzoic acid and diethylene glycol, etherified products of hydroxystyrene and diol, etherified products of hydroxystyrene and diethylene glycol, and the like. Examples include monomers having a hydroxy group and a styrene group.
In addition, specifically as a monomer which forms a thermally crosslinkable structural unit, the monomer described in patent 5626493 gazette paragraphs 0075-0079 can be used specifically ,.

The thermal crosslinkable structural unit possessed by the copolymer may be one type or two or more types.
For the synthesis of the copolymer, a monomer having a thermally crosslinkable group that forms the thermally crosslinkable structural unit can be used. Monomers having a thermally crosslinkable group can be used alone or in combination of two or more.

  As a content rate of the heat-crosslinkable structural unit in a copolymer, when the whole copolymer is 100 mol%, it can set within the range of 10 mol%-90 mol%, Preferably it is 20 mol%- It is in the range of 80 mol%. When the content ratio of the thermally crosslinkable structural unit is small, sufficient thermosetting property cannot be obtained, and it may be difficult to maintain good liquid crystal alignment ability. In addition, when the content ratio of the thermally crosslinkable structural unit is large, the content ratio of the photoalignable structural unit is relatively decreased, the sensitivity is lowered, and it may be difficult to impart good liquid crystal alignment ability. .

(3) Other Structural Units In the present invention, the copolymer has a structural unit having neither a photo-alignable group nor a heat-crosslinkable group in addition to the photo-alignment structural unit and the heat-crosslinkable structural unit. You may do it. By including other structural units in the copolymer, for example, solvent solubility, heat resistance, reactivity, and the like can be improved.

  Examples of the monomer unit constituting the structural unit having no photo-alignable group and heat-crosslinkable group include acrylic acid ester, methacrylic acid ester, maleimide, acrylamide, acrylonitrile, maleic anhydride, styrene, vinyl and the like. Can be mentioned. Of these, acrylic acid esters, methacrylic acid esters, and styrene are preferred as in the case of the thermally crosslinkable structural unit.

  Examples of the monomer that forms the structural unit having no photo-alignable group and heat-crosslinkable group include, for example, acrylic ester compounds, methacrylic ester compounds, maleimide compounds, acrylamide compounds, acrylonitrile, maleic anhydride, styrene. Compound, vinyl compound and the like can be mentioned. Specifically, for example, monomers described in paragraphs 0036 to 0040 of International Publication No. 2010/150748 can be used.

  The constitutional unit having no photo-alignable group and heat-crosslinkable group in the copolymer may be one kind or two or more kinds.

  The content of the structural unit in the copolymer is preferably in the range of 0 mol% to 50 mol%, and in the range of 0 mol% to 30 mol%, assuming that the entire copolymer is 100 mol%. More preferably, it is within. When the content ratio of the structural unit is large, the content ratio of the photoalignable structural unit and the thermally crosslinkable structural unit is relatively reduced, the sensitivity is lowered, and it becomes difficult to impart good liquid crystal alignment ability. Moreover, sufficient thermosetting cannot be obtained, and it may be difficult to maintain good liquid crystal alignment ability.

(4) Copolymer The number average molecular weight of the copolymer is not particularly limited, and can be, for example, about 3,000 to 200,000, preferably in the range of 4,000 to 100,000. It is. If the number average molecular weight is too large, the solubility in a solvent may be lowered or the viscosity may be increased, resulting in a decrease in handleability, and it may be difficult to form a uniform film. On the other hand, if the number average molecular weight is too small, curing may be insufficient during thermosetting, and solvent resistance and heat resistance may be reduced.
The number average molecular weight can be measured by gel permeation chromatography (GPC) method.

Examples of the method for synthesizing the copolymer include a method of copolymerizing a monomer having a photoalignable group and a monomer having a thermally crosslinkable group.
The method for synthesizing the copolymer is not particularly limited. For example, the copolymer can be obtained by a polymerization reaction in a solvent in which a monomer having a photoalignable group, a monomer having a heat crosslinkable group, and a polymerization initiator coexist. Can do. In that case, the solvent used will not be specifically limited if it dissolves the monomer which has a photo-alignment group, the monomer which has a heat crosslinkable group, a polymerization initiator, etc. Specifically, it can be the same as that of the solvent used for the thermosetting composition which has the photo-alignment property mentioned later. Moreover, the temperature in the case of a polymerization reaction can be set, for example at about 50 to 120 degreeC. The copolymer obtained by the above method is usually in the state of a solution dissolved in a solvent.

The copolymer obtained by the above method can be used as it is, but can also be purified and used by the method shown below.
That is, the copolymer solution obtained by the above method is poured into diethyl ether, methanol, water or the like while stirring to reprecipitate, and the resulting precipitate is filtered and washed, and then at normal pressure or reduced pressure. Then, it can be dried at room temperature or by heating to obtain a powder of the copolymer. By this operation, the polymerization initiator coexisting with the copolymer and the unreacted monomer can be removed, and as a result, a purified copolymer powder is obtained. If sufficient purification cannot be achieved by a single operation, the obtained powder may be redissolved in a solvent and the above operation may be repeated.

The copolymer may be used in the form of a solution when the copolymer is synthesized, in the form of a powder, or in the form of a solution in which purified powder is redissolved in a solvent described later.
Further, the copolymer may be one kind or a mixture of plural kinds of copolymers.

2. Crosslinking agent The thermosetting composition having photo-alignment properties of the present invention contains a crosslinking agent that binds to the thermally crosslinkable group of the thermally crosslinkable structural unit. A crosslinking agent can improve heat resistance and solvent resistance by combining with the thermally crosslinkable structural unit of the copolymer. The crosslinking agent is bonded to at least one of a hydroxy group and a carboxy group of a thermally crosslinkable polymerizable compound containing an aromatic hydrocarbon group, which will be described later, and is thermally crosslinkable polymerizable containing an aromatic hydrocarbon group. Immobilizing the compound on the surface of the alignment layer contributes to improved adhesion.

As the crosslinking agent, it is preferable to select and use a compound that binds to the thermally crosslinkable group of the thermally crosslinkable structural unit and also bonds to at least one of a hydroxy group and a carboxy group of the compound described later.
Examples of such a crosslinking agent include an epoxy compound, a methylol compound, an isocyanate compound, and the like. Of these, methylol compounds are preferred.
Further, the crosslinking agent may be a compound obtained by condensing a melamine compound, urea compound, glycoluril compound and benzoguanamine compound in which a hydrogen atom of an amino group is substituted with a methylol group or an alkoxymethyl group.
Furthermore, as a crosslinking agent, a polymer produced using an acrylamide compound or a methacrylamide compound substituted with a hydroxymethyl group or an alkoxymethyl group can also be used.
Specifically, for example, a crosslinking agent described in paragraphs 0047 to 0050 of International Publication No. 2010/150748 can be used.

  A cross-linking agent containing a plurality of benzene rings in the molecule can also be used. Examples of the crosslinking agent containing a plurality of benzene rings in the molecule include, for example, a phenol derivative having at least two hydroxymethyl groups or alkoxymethyl groups and a molecular weight of 1200 or less, or at least two free N-alkoxymethyl groups. Melamine-formaldehyde derivatives and alkoxymethylglycoluril derivatives having A phenol derivative having a hydroxymethyl group can be obtained by reacting a corresponding phenol compound having no hydroxymethyl group with formaldehyde in the presence of a base catalyst.

  These crosslinking agents can be used alone or in combination of two or more.

  The content of the crosslinking agent in the thermosetting composition having photo-alignment property of the present invention is preferably in the range of 1 to 40 parts by mass, more preferably 100 parts by mass of the copolymer. It is in the range of 2 to 30 parts by mass. If the content is too small, the heat resistance and solvent resistance of the cured film formed from the thermosetting composition having photo-alignment properties may decrease, and the liquid crystal alignment ability may decrease. Moreover, when there is too much content, liquid crystal aligning ability and storage stability may fall.

3. Thermally crosslinkable polymerizable compound containing an aromatic hydrocarbon group The present invention includes a compound having at least one of a hydroxy group and a carboxy group, an aromatic hydrocarbon group, and an ethylenically unsaturated double bond group. Since at least one of the hydroxy group and the carboxy group functions as a thermally crosslinkable group, and the ethylenically unsaturated double bond group functions as a polymerizable group, the compound includes a thermal hydrocarbon group containing an aromatic hydrocarbon group. Functions as a crosslinkable polymerizable compound.

At least one of the hydroxy group and the carboxy group is a functional group capable of reacting with the crosslinking agent. At least one of a hydroxy group and a carboxy group is immobilized on the alignment layer by reacting with the crosslinking agent.
The thermally crosslinkable polymerizable compound containing an aromatic hydrocarbon group has at least one of a hydroxy group and a carboxy group in one molecule. If at least one of the hydroxy group and the carboxy group is too much in one molecule of the compound, the compound is strongly fixed to the alignment layer, and the ethylenically unsaturated double bond group may not easily react. The thermally crosslinkable polymerizable compound containing an aromatic hydrocarbon group preferably has 1 to 2 hydroxyl groups and carboxy groups in one molecule, and more preferably 1 in one molecule.

  Moreover, when it has a phenolic hydroxy group, since the reactivity with a crosslinking agent becomes high, it is preferable from the point of adhesive improvement.

The ethylenically unsaturated double bond group is a radical polymerizable group, and an alignment layer is formed using the thermosetting composition having photo-alignment property of the present invention, and a polymerizable liquid crystal composition is used on the alignment layer. When the liquid crystal layer is formed, it can react with the ethylenically unsaturated double bond group of the polymerizable liquid crystal compound contained in the polymerizable liquid crystal composition. The radical polymerizable group is a functional group that can be polymerized by irradiation with active energy rays such as ultraviolet rays or the action of radicals. Examples of the ethylenically unsaturated double bond group include a vinyl group (H ₂ C═CH—), an acryloyl group (H ₂ C═CH—C (═O) —), and a methacryloyl group (H ₂ C═C ( CH ₃ ) —C (═O) —) and the like.
The thermally crosslinkable polymerizable compound has one or more ethylenically unsaturated double bond groups in one molecule.

The thermally crosslinkable polymerizable compound preferably has a double bond of an ethylenically unsaturated double bond group at the terminal.
As the thermally crosslinkable polymerizable compound, a compound represented by the following formula (6) can be exemplified.
Formula (6)
(R ³¹ ) _s- (L ³ )-(Y ³ ) _t
(In the above formula (6), R ³¹ is an ethylenically unsaturated double bond group, Y ³ is at least one of a hydroxy group and a carboxy group, and L ³ has an (s + t) valence containing an aromatic hydrocarbon group. S represents a number contained in one molecule of an ethylenically unsaturated double bond group, and is 1 or more, and t is contained in one molecule of at least one of a hydroxy group and a carboxy group. Represents a number and is one or more.)

The ethylenically unsaturated double bond group R ³¹ and at least one of the hydroxy group and the carboxy group Y ³ are as described above.
s, t are the independently 2 or more, if R ³¹ and Y ³ in one molecule is there exist a plurality independently each a plurality of R ³¹ and Y ³ independently may be identical to one another May be different.

L ³ is a (s + t) -valent linking group containing an aromatic hydrocarbon group.
The (s + t) -valent linking group necessarily includes an aromatic hydrocarbon group, and further includes, for example, an ether bond, a thioether bond, an ester bond, a thioester bond, a carbonyl bond, a thiocarbonyl bond, and a divalent amino group (—NR— Wherein R is hydrogen or a hydrocarbon group), an amide group, and a group in combination with one or more groups selected from the group consisting of a chain, branched or cyclic aliphatic hydrocarbon group, etc. Is mentioned.

The aromatic hydrocarbon constituting the aromatic hydrocarbon group preferably has 6 to 14 carbon atoms, and examples thereof include benzene, naphthalene, biphenyl, and anthracene. Among them, as the aromatic hydrocarbon constituting the aromatic hydrocarbon group, benzene is preferable from the viewpoint of increasing the affinity with the photoalignment group.
The aromatic hydrocarbon group may have a monovalent substituent. Examples of the monovalent substituent include a chain, branched or cyclic monovalent aliphatic hydrocarbon group, a halogen atom, an alkoxy group, and a cyano group.

The thermally crosslinkable polymerizable compound includes a compound having at least one acryloyl group and methacryloyl group and a glycidyl group, such as glycidyl methacrylate, and an aromatic hydrocarbon group having a phenolic hydroxy group. A reaction product with the compound to be contained is also preferable from the viewpoint of improving adhesion. In this case, the reaction product has an alcoholic hydroxy group by the reaction of a glycidyl group and a phenolic hydroxy group near the center of the molecule, and at least one of an acryloyl group and a methacryloyl group near the end, Since the structure has an aromatic hydrocarbon group, it reacts with the crosslinking agent at the alcoholic hydroxy group near the center of the molecule, and is affected by the effects of the ethylenically unsaturated double bond group and the aromatic hydrocarbon group near the molecular end. The interaction between the liquid crystal molecules described later and the π-electron system becomes stronger on the alignment film surface, the reaction with the ethylenically unsaturated double bond group of the polymerizable liquid crystal compound is more likely to proceed, and the adhesion to the liquid crystal layer is improved. It is estimated that it will become better.
The total number of carbon atoms and heteroatoms constituting the bond between the alcoholic hydroxy group and the aromatic hydrocarbon ring is preferably 3 or more and 6 or less, and the alcoholic hydroxy group and The total number of carbon atoms and hetero atoms constituting the bond between the ethylenically unsaturated double bond group and the carbon atom is preferably 3 or more and 5 or less.

  Examples of the thermally crosslinkable polymerizable compound include, but are not limited to, compounds shown below.

The thermally crosslinkable polymerizable compound may be a commercially available product having a corresponding structure, or may be obtained by appropriately synthesizing. For example, a compound having an aromatic hydrocarbon group and a glycidyl ether group is reacted with acrylic acid or methacrylic acid, or a compound having at least one acryloyl group or methacryloyl group and a glycidyl group, and a phenolic hydroxy group Or a compound having an aromatic hydrocarbon group having two carboxy groups, a compound having at least one of acryloyl group and methacryloyl group and a hydroxy group, and a compound having an aromatic hydrocarbon group having two carboxy groups Or by reacting at least one of acrylic acid chloride and methacrylic acid chloride with an aromatic hydrocarbon having two hydroxy groups.
Moreover, the said heat-crosslinkable polymeric compound can be used individually or in combination of 2 or more types.

  The molecular weight of the thermally crosslinkable polymerizable compound is preferably within the range of 120 to 1000, more preferably within the range of 120 to 500, and even more preferably within the range of 150 to 400. If the molecular weight is too large, when the alignment layer is formed using the thermosetting composition having photo-alignment property of the present invention, the photo-alignment compound may not be localized near the surface of the alignment layer.

  The content of the thermally crosslinkable polymerizable compound in the photocurable thermosetting composition of the present invention is in the range of 5 to 60 parts by mass with respect to 100 parts by mass of the copolymer. More preferably, it is in the range of 10 to 50 parts by mass, and further preferably in the range of 20 to 50 parts by mass. If the content of the heat-crosslinkable polymerizable compound is too small, the effect of improving the adhesion with the liquid crystal layer can be obtained when the alignment layer is formed using the thermosetting composition having the photo-alignment property of the present invention. There is a possibility that it cannot be obtained sufficiently. Moreover, when there is too much content of the said heat crosslinkable polymeric compound, content of a copolymer will decrease relatively and there exists a possibility that favorable liquid crystal aligning ability may not be obtained.

4). Acid or acid generator The thermosetting composition having photo-alignment property of the present invention may contain an acid or an acid generator. With the acid or the acid generator, the thermosetting reaction of the thermosetting composition having photo-alignment property of the present invention can be promoted.

  Examples of the acid or acid generator include a sulfonic acid group-containing compound, hydrochloric acid or a salt thereof, and a compound that generates an acid upon thermal drying and curing of a coating film, that is, a thermal decomposition at a temperature of 50 ° C. to 250 ° C. The compound is not particularly limited as long as it is a compound that generates an acid. Specifically, what is described in paragraph 0054 of International Publication No. 2010/150748 can be used.

  The content of the acid or acid generator in the thermosetting composition having photo-alignment property of the present invention is preferably within a range of 0.01 to 20 parts by mass with respect to 100 parts by mass of the copolymer. More preferably, it is in the range of 0.05 to 10 parts by mass, and further preferably in the range of 0.1 to 5 parts by mass. By making content of an acid or an acid generator into the said range, sufficient thermosetting and solvent tolerance can be provided, and also the high sensitivity with respect to light irradiation can be provided. On the other hand, when there is too much content, the storage stability of the thermosetting composition which has photoalignment may fall.

5. Photoinitiator The thermosetting composition having photoalignment property of the present invention preferably further contains a photoinitiator from the viewpoint of obtaining an alignment layer having better adhesion to the liquid crystal layer.
An ethylenically unsaturated double bond group in the thermally crosslinkable polymerizable compound containing the aromatic hydrocarbon group by further containing a photoinitiator in combination with the thermally crosslinkable polymerizable compound containing the aromatic hydrocarbon group It is estimated that the reaction with the ethylenically unsaturated double bond group of the polymerizable liquid crystal compound contained in the polymerizable liquid crystal composition can be promoted, and the adhesion with the liquid crystal layer is further improved.

  As the photoinitiator, a radical photopolymerization initiator that generates radical species by light irradiation is preferably used. When the thermosetting composition having photo-alignment property of the present invention contains the acid or acid generator, the photo-initiator is, for example, a basic light such as an aminoalkylphenone photo-initiator. It is preferably not an initiator, and is preferably a photoinitiator having no basic group.

  Examples of the photoinitiator include acylphosphine oxide photoinitiators, oxime ester photoinitiators, α-hydroxyacetophenone photoinitiators, and benzyl ketal photoinitiators.

Although the specific example of a photoinitiator is given to the following, it is not limited to these.
Specific examples of the acylphosphine oxide photoinitiator include 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, and the like.
Specific examples of the oxime ester photoinitiator include 1.2-octanedione, 1- [4- (phenylthio)-, 2- (O-benzoyloxime)], ethanone, 1- [9-ethyl-6- (2-methylbenzoyl) -9H-carbazol-3-yl]-, 1- (O-acetyloxime) and the like.
Specific examples of the α-hydroxyacetophenone photoinitiator include 1-hydroxy-cyclohexyl-phenyl-ketone, 2-hydroxy-1- {4- [4- (2-hydroxy-2-methyl-propionyl) -benzyl]. Phenyl} -2-methyl-propan-1-one, 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propan-1-one, oligo [2-hydroxy- 2-methyl-1- {4- (1-methylvinyl) phenyl} propanone], 2-hydroxy-2-methyl-1-phenyl-propan-1-one, 2-hydroxy-1- (4- (4- (2-hydroxy-3,5,2-methylpropionyl) -benzyl) -phenyl) -2-methylpropan-1-one and the like.
Specific examples of the benzyl ketal photoinitiator include 2,2-dimethoxy-1,2-diphenylethane-1-one.

Among them, at least one of an acyl phosphine oxide photoinitiator and an oxime ester photoinitiator is preferable from the viewpoint of high reactivity.
As a photoinitiator, it can be used individually or in combination of 2 or more types.

  The content of the photoinitiator in the photo-curable thermosetting composition of the present invention is preferably in the range of 5 to 30 parts by mass, more preferably 100 parts by mass of the copolymer. Is within the range of 5 to 20 parts by mass. When the content is too small, the effect of the photoinitiator may not be sufficiently obtained, and when the content is too large, the orientation may be deteriorated.

6). Sensitizer The thermosetting composition having photo-alignment property of the present invention may contain a sensitizer. Photosensitizers such as photodimerization reaction and photoisomerization reaction can be promoted by the sensitizer.

As the sensitizer, specifically, those described in paragraph 0057 of International Publication No. 2010/150748 can be used.
Of these, benzophenone derivatives and nitrophenyl compounds are preferred. Sensitizers can be used alone or in combination of two or more compounds.

  The content of the sensitizer in the thermosetting composition having photo-alignment property of the present invention is preferably in the range of 0.1 to 20 parts by mass with respect to 100 parts by mass of the copolymer. More preferably, it exists in the range of 0.2 mass part-10 mass parts. If the content is too small, the effect as a sensitizer may not be sufficiently obtained. If the content is too large, the transmittance may be lowered and the coating film may be roughened.

7). Solvent The thermosetting composition having photo-alignment property of the present invention is mainly used in a solution state dissolved in a solvent.
The solvent is not particularly limited as long as it can dissolve each of the above components, and specifically, those described in paragraph 0061 of International Publication No. 2010/150748 can be used.
A solvent can be used individually by 1 type or in combination of 2 or more types.

8). Additives The thermosetting composition having the photo-alignment property of the present invention is a silane coupling agent, a surfactant, a rheology modifier, a pigment, a dye, a storage as long as the effects of the present invention are not impaired. Stabilizers, antifoaming agents, antioxidants and the like can be contained. Moreover, a liquid crystalline monomer can be contained in order to improve the liquid crystal alignment ability.

9. Thermosetting composition having photo-alignment property The thermosetting composition having photo-alignment property of the present invention is usually used as a solution in which each component is dissolved in a solvent. The ratio of the solid content in the thermosetting composition having photo-alignment property of the present invention is not particularly limited as long as each component is uniformly dissolved in the solvent, and is 0.1% by mass to 80% by mass. It is within the range, preferably within the range of 0.5% by mass to 60% by mass, and more preferably within the range of 0.5% by mass to 40% by mass. If the ratio of the solid content is too small, it may be difficult to impart liquid crystal alignment ability and thermosetting property. Moreover, when there are too many ratios of solid content, the viscosity of the thermosetting composition which has photo-orientation property will become high, and it will become difficult to form a uniform film | membrane.
In addition, solid content means what remove | excluded the solvent from all the components of the thermosetting composition which has photo-orientation property.

The method for preparing the thermosetting composition having photo-alignment property of the present invention is not particularly limited. However, since the storage stability becomes long, the copolymer, the crosslinking agent, the thermocrosslinkable polymerizable compound, And other additives are mixed, and an acid or an acid generator is added later. In addition, when adding an acid or an acid generator from the beginning, it is preferable to use as the acid or an acid generator a compound that generates an acid by thermal decomposition during drying and heat curing of the coating film.
In the preparation of the thermosetting composition having photo-alignment property of the present invention, a copolymer solution obtained by a polymerization reaction in a solvent can be used as it is. In this case, as described above, the crosslinking agent, the thermally crosslinkable polymerizable compound, and other additives are added to the copolymer solution to form a uniform solution, and then the acid or acid generator is added. At this time, a solvent may be further added for the purpose of adjusting the concentration. At this time, the solvent used in the process of forming the copolymer and the solvent used for adjusting the concentration of the thermosetting composition having photo-alignment property may be the same or different.

  Moreover, it is preferable to use, after filtering the prepared solution of the thermosetting composition which has photo-alignment property using the filter etc. with a pore diameter of about 0.2 micrometer.

10. Uses Examples of uses of the thermosetting composition having photo-alignment properties of the present invention include alignment layers for various optical elements such as retardation plates and alignment layers for liquid crystal display elements. The thermosetting composition having photo-alignment property of the present invention can also be used for insulating films and protective films in various devices such as liquid crystal display elements, organic EL elements, TFTs, and color filters. For example, organic EL elements Insulating film, TFT interlayer insulating film, color filter overcoat layer, and the like.

B. Alignment layer The alignment layer of the present invention comprises a photodimerization structure or photoisomerization structure of a photoalignment group possessed by a photoalignment structural unit, and a thermally crosslinkable group possessed by a thermally crosslinkable structural unit and a crosslinking agent. A copolymer having a crosslinked structure,
A compound having a crosslinked structure formed by bonding at least one of a hydroxy group and a carboxy group and a crosslinking agent, an aromatic hydrocarbon group, and an ethylenically unsaturated double bond group;
It is characterized by containing.

  Here, the cross-linked structure refers to a three-dimensional network structure. The crosslinked structure includes a crosslinked structure formed by bonding a thermally crosslinkable group of the thermally crosslinkable structural unit of the copolymer and a crosslinking agent, and at least one of a hydroxy group and a carboxy group of the compound and a crosslinking agent. And a crosslinked structure formed by bonding. The crosslinked structure does not include a structure in which photoalignable groups are crosslinked by a photodimerization reaction and a structure in which ethylenically unsaturated double bond groups are polymerized.

According to the present invention, the alignment layer includes a predetermined photodimerization structure or photoisomerization structure, a copolymer having a predetermined crosslink structure, an aromatic hydrocarbon group, a predetermined crosslink structure, and ethylene. Containing a compound having a polymerizable unsaturated double bond group, having good liquid crystal alignment ability, excellent adhesion to the liquid crystal layer, and having good heat resistance and solvent resistance It is.
Hereinafter, each structure in the alignment layer of this invention is demonstrated.

1. Copolymer contained in alignment layer The alignment layer includes a photodimerization structure or photoisomerization structure of a photoalignment group of a photoalignment structural unit, and a heat crosslinkable group and a crosslinking agent of a heat crosslinkable structural unit. A copolymer having a crosslinked structure formed by bonding is included.

The copolymer contained in the alignment layer is obtained by thermosetting the copolymer having the photo-alignment structural unit and the heat-crosslinkable structural unit described in “A. Thermosetting composition having photo-alignment”. It can be formed by photo-alignment. In the present invention, a crosslinking agent is used, and the thermally crosslinkable group of the thermally crosslinkable structural unit is bonded to the crosslinking agent. Therefore, the crosslinked structure is a structure in which the thermally crosslinkable group and the crosslinking agent are crosslinked by heating. When the thermally crosslinkable structural unit of the copolymer has a crosslinkable group, as the crosslink structure, the heat crosslinkable group possessed by the heat crosslinkable structural unit and the crosslinkable group possessed by the heat crosslinkable structural unit are combined. It may contain a crosslinked structure.
As the cross-linking agent, the cross-linking agent described in “A. Thermosetting composition having photo-alignment” can be used, and in the cross-linked structure, a residue of the cross-linking agent after the cross-linking agent has reacted. Is included.

  For example, when the cross-linking agent is hexamethoxymethylmelamine, the cross-linked structure is, for example, as shown below. In addition, in the following formula | equation, each code | symbol is the same as that of the said Formula (1). The following copolymer is an example, and the monomer unit and the residue of the thermally crosslinkable group are not limited to the following.

In addition, since each structural unit of the copolymer was described in detail in the above-mentioned “A. Thermosetting composition having photo-alignment”, description thereof is omitted here.
It can be confirmed that the alignment layer contains the copolymer by collecting and analyzing the material from the alignment layer. As an analysis method, NMR, IR, GC-MS, XPS, TOF-SIMS, and a combination thereof can be applied.

The photodimerization structure in the copolymer is a structure in which the photoalignment groups of the photoalignment structural unit represented by the above formula (1) are crosslinked by a photodimerization reaction, and has a cyclopropane skeleton.
The photodimerization reaction is a reaction as shown below, and is a reaction in which an olefin structure contained in a photoalignable group forms a cyclopropane skeleton by a photoreaction. Xa to Xd and Xa ′ to Xd ′ are different depending on the type of photo-alignment group.

  The photodimerization structure is preferably a photodimerization structure of a cinnamoyl group. Specifically, a structure in which cinnamoyl groups described in “A. Thermosetting composition having photo-alignment property” are cross-linked by a photodimerization reaction is preferable. Among these, the alignment layer preferably has a photodimerization structure represented by the following formulas (7-1) and (7-2). In addition, in the following formula | equation, each code | symbol is the same as that of the said Formula (2-1), (2-2), and (2-3).

  When the alignment layer has a photodimerization structure represented by the above formulas (7-1) and (7-2), many aromatic rings are arranged and many π electrons are contained. Therefore, it is considered that the affinity with the liquid crystal layer formed on the alignment layer is increased, the liquid crystal alignment ability is improved, and the adhesion with the liquid crystal layer is further increased.

Further, the photoisomerization structure in the copolymer is a structure in which the photoalignment group of the photoalignment structural unit is isomerized by a photoisomerization reaction. For example, in the case of a cis-trans isomerization reaction, the photoisomerization structure may be either a structure in which a cis isomer is changed to a trans isomer or a structure in which a trans isomer is changed to a cis isomer.
For example, when the photoalignment group is a cinnamoyl group, the photoisomerization reaction is a reaction as shown below, and the olefin structure contained in the photoalignment group is a reaction that forms a cis isomer or a trans isomer by the photoreaction. . Xa to Xd differ depending on the type of photo-alignment group.

  The photoisomerization structure is preferably a photoisomerization structure of a cinnamoyl group. Specifically, a structure in which the cinnamoyl group described in “A. Thermosetting composition having photo-alignment property” is isomerized by a photoisomerization reaction is preferable. In this case, the photoisomerization structure may be either a structure in which the cis form is changed to a trans form or a structure in which the trans form is changed to a cis form. Among them, the alignment layer has a photoisomerization structure of a cinnamoyl group represented by the above formulas (2-1) and (2-2) as represented by the following formulas (8-1) and (8-2). It is preferable to have.

  In addition, it can be analyzed by NMR or IR that the alignment layer has the above-mentioned photodimerization structure or photoisomerization structure.

2. Polymerizable compound contained in alignment layer The alignment layer in the present invention has a crosslinked structure formed by bonding at least one of a hydroxy group and a carboxy group and a crosslinking agent, an aromatic hydrocarbon group, and an ethylenically unsaturated double bond. A compound having a group (hereinafter, simply referred to as a polymerizable compound contained in the alignment layer) is included.

The compound having a crosslinked structure formed by bonding at least one of the hydroxy group and carboxy group and a crosslinking agent, an aromatic hydrocarbon group, and an ethylenically unsaturated double bond group has the above-mentioned “A. Photoalignment”. It can be formed by crosslinking a compound having at least one of a hydroxy group and a carboxy group, an aromatic hydrocarbon group, and an ethylenically unsaturated double bond group described in “thermosetting composition” with a crosslinking agent. . The crosslinked structure includes at least one residue of a hydroxy group and a carboxy group and a residue of the crosslinking agent after the crosslinking agent has reacted.
Since the aromatic hydrocarbon group and the ethylenically unsaturated double bond group of the polymerizable compound contained in the alignment layer are described in detail in “A. Thermosetting composition having photo-alignment” above. Explanation here is omitted.

  Whether the alignment layer contains a polymerizable compound contained in the alignment layer can be confirmed by collecting and analyzing the material from the alignment layer. As an analysis method, NMR, IR, GC-MS, XPS, TOF-SIMS, and a combination thereof can be applied.

3. Alignment layer The alignment layer may contain an acid or an acid generator, a photoinitiator, a sensitizer, other additives, and decomposition products thereof. In addition, about these additives, it is the same as that of what was described in said "A. Thermosetting composition which has photo-alignment property".
In addition, the alignment layer is an unreacted copolymer having a photo-alignable structural unit and a thermally crosslinkable structural unit, a crosslinking agent, at least one of a hydroxy group and a carboxy group, an aromatic hydrocarbon group, and an ethylenic group. You may contain the compound which has a saturated double bond group.

The alignment layer is formed from the thermosetting composition having the above-described photo-alignment property.
Here, the alignment layer formed from the thermosetting composition having photo-alignment refers to an alignment layer obtained by thermo-curing a film containing a thermo-setting composition having photo-alignment and further photo-aligning. Say. That is, the alignment layer is first applied on a substrate to form a coating film of the thermosetting composition having the photo-alignment property, and the coating film is heated to form a cured film. It can be formed by irradiating polarized ultraviolet rays.
The method for forming the coating film, the method for forming the thermosetting film, the method for photo-alignment, and the like may be the same as the methods described in the method for manufacturing the substrate with an alignment layer described later, and thus description thereof is omitted here.

  In addition, it can confirm that an alignment layer is formed from the thermosetting composition which has the above-mentioned photo-alignment property by extract | collecting and analyzing a material from an alignment layer. As an analysis method, NMR, IR, GC-MS, XPS, TOF-SIMS, and a combination thereof can be applied.

C. 1. Substrate with alignment layer and method for producing the same A substrate with alignment layer of the present invention comprises a substrate and the alignment layer according to the present invention disposed on the substrate.

  FIG. 1 is a schematic sectional view showing an example of a substrate with an alignment layer of the present invention. In the substrate 1 with an alignment layer illustrated in FIG. 1, an alignment layer 3 is formed on the substrate 2.

According to the present invention, by having the above-mentioned alignment layer, it is possible to provide a substrate with an alignment layer having excellent liquid crystal alignment ability, adhesion to the liquid crystal layer, heat resistance, and solvent resistance.
Hereinafter, each structure in the board | substrate with an alignment layer of this invention is demonstrated.

1. Alignment layer The alignment layer in the substrate with an alignment layer of the present invention is the alignment layer according to the present invention, and has a function of aligning liquid crystal molecules. Since the alignment layer has been described in detail in “B. Alignment layer” above, description thereof is omitted here.

2. Substrate The substrate used in the present invention supports the alignment layer.
The substrate is not particularly limited, and is appropriately selected depending on the application. Examples of the material for the substrate include glass, quartz, polyethylene terephthalate, polycarbonate, triacetyl cellulose, polyester, acrylic and other resins, metals such as aluminum, and ceramics such as silicon and silicon nitride. The substrate may be subjected to a surface treatment.
The substrate may or may not have flexibility, and is appropriately selected according to the use or the like.

3. Conductive layer In the present invention, a conductive layer may be formed between the substrate and the alignment layer. The conductive layer functions, for example, as an electrode for various devices. Examples of the material for the conductive layer include transparent conductive materials such as ITO and IZO, and metal materials such as aluminum, molybdenum, and chromium.

4). Applications Examples of the use of the substrate with an alignment layer of the present invention include various optical elements such as a retardation plate, liquid crystal display elements, and light emitting elements.

5. Manufacturing method of substrate with alignment layer The manufacturing method of a substrate with alignment layer of the present invention is a method of applying thermosetting composition having photo-alignment according to the present invention on a substrate, and thermosetting having photo-alignment. Forming a cured film by forming a coating film of the adhesive composition and heating the coating film;
And a step of forming an alignment layer by irradiating the cured film with polarized ultraviolet rays.

  The application method of the thermosetting composition having photo-alignment is not particularly limited as long as it is a method capable of forming a uniform film on the substrate. For example, spin coating method, roll coating method, rod bar coating Method, spray coating method, air knife coating method, slot die coating method, wire bar coating method, flow coating method, ink jet method and the like.

  For example, a hot plate or an oven can be used for drying the coating film. The temperature can be set, for example, at about 30 ° C. to 160 ° C., and preferably within the range of 50 ° C. to 140 ° C. The time can be set, for example, for about 20 seconds to 60 minutes, and is preferably in the range of 30 seconds to 10 minutes.

  Even when a cured film is formed by heating the coating film, a hot plate, an oven, or the like can be used. The temperature can be set, for example, at about 30 ° C to 250 ° C. The time can be set, for example, for about 20 seconds to 60 minutes. Moreover, drying and heat curing of the coating film may be performed simultaneously or separately.

  The film thickness of the cured film obtained by thermosetting the thermosetting composition having photo-alignment is appropriately selected according to the application and the like, and can be, for example, about 0.05 μm to 30 μm. In addition, when the film thickness of a cured film is too thin, sufficient liquid crystal aligning ability may not be obtained.

The obtained cured film can be irradiated with polarized ultraviolet rays to cause a photoreaction and develop anisotropy. The wavelength of polarized ultraviolet light is usually in the range of 150 nm to 450 nm. Moreover, the irradiation direction of polarized ultraviolet rays can be perpendicular or oblique to the substrate surface.
As described above, an alignment layer can be formed.

D. Retardation plate The retardation plate of the present invention comprises a substrate,
A photo-dimerization structure or photo-isomerization structure of a photo-alignment group of a photo-alignment constituent unit, and a heat-crosslinkable group of a heat-cross-linkable constitution unit and a cross-linking agent, which are arranged on the substrate, are combined. It has a structure in which a copolymer having a crosslinked structure, a crosslinked structure formed by bonding at least one of a hydroxy group and a carboxy group and a crosslinking agent, an aromatic hydrocarbon group, and an ethylenically unsaturated double bond group are polymerized. An alignment layer containing a compound;
A retardation layer having a structure in which an ethylenically unsaturated double bond group of the polymerizable liquid crystal composition having an ethylenically unsaturated double bond group disposed on the alignment layer is polymerized. Is.

  FIG. 2 is a schematic sectional view showing an example of the retardation plate of the present invention. In the retardation plate 10 illustrated in FIG. 2, the alignment layer 12 is formed on the substrate 11, and the retardation layer 13 is formed on the alignment layer 12.

  According to the present invention, the alignment layer comprises a copolymer having a predetermined photodimerization structure or photoisomerization structure and a crosslinked structure, a predetermined crosslinked structure, an aromatic hydrocarbon group, and an ethylenically unsaturated double bond. A compound having a bonding group, and having a structure in which the ethylenically unsaturated double bond group is polymerized, it has excellent liquid crystal alignment ability, adhesion to the liquid crystal layer, heat resistance and solvent resistance, and optical properties. A retardation plate with good characteristics can be obtained.

  In addition, since it described in the said "C. board | substrate with an orientation layer" about the board | substrate, description here is abbreviate | omitted. Hereinafter, the other structure in the phase difference plate of this invention is demonstrated.

1. Alignment layer in phase difference plate The alignment layer in the phase difference plate has a photodimerization structure or photoisomerization structure of a photoalignment group of a photoalignment constituent unit and a thermally crosslinkable constitution unit, which are arranged on a substrate. A copolymer having a crosslinked structure formed by bonding a thermally crosslinkable group and a crosslinking agent, a crosslinked structure formed by bonding at least one of a hydroxy group and a carboxy group and a crosslinking agent, an aromatic hydrocarbon group, and ethylene And a compound having a structure in which a polymerizable unsaturated double bond group is polymerized (hereinafter simply referred to as a compound containing an aromatic hydrocarbon group in the alignment layer).

  The copolymer is the same as the copolymer in “B. Alignment layer”, and the description thereof is omitted here.

The structure in which the ethylenically unsaturated double bond group of the compound containing an aromatic hydrocarbon group in the alignment layer is polymerized is obtained by applying a polymerizable liquid crystal composition on the alignment layer to the phase transition temperature of the polymerizable liquid crystal composition. It can be obtained by heating to align the liquid crystal molecules with the alignment layer and curing.
The structure in which the ethylenically unsaturated double bond group of the compound containing the aromatic hydrocarbon group in the alignment layer is polymerized is the ethylenically unsaturated double bond group of the compound containing the aromatic hydrocarbon group in the alignment layer, Or, it is a structure in which the ethylenically unsaturated double bond group of the polymerizable liquid crystal compound contained in the retardation layer and the ethylenically unsaturated double bond group of the compound containing an aromatic hydrocarbon group in the alignment layer are polymerized. .
Whether the alignment layer has the above structure can be analyzed by XPS or IR.

2. Retardation layer The retardation layer in this invention is formed on the said orientation layer, and contains the hardened | cured material of a polymeric liquid crystal composition.
As a polymeric liquid crystal composition, what contains the polymeric liquid crystal compound which has a polymeric group can be used, and what is generally used for a phase difference layer can be used.
Examples of the ethylenically unsaturated double bond group possessed by the polymerizable liquid crystal compound include an acryloyl group and a methacryloyl group.

Some polymerizable liquid crystal compositions have alignment properties such as horizontal alignment, cholesteric alignment, vertical alignment, and hybrid alignment, and are appropriately selected depending on the combination with the alignment layer, a desired retardation, and the like.
The retardation layer can be obtained by applying a polymerizable liquid crystal composition on the alignment layer, heating to the phase transition temperature of the polymerizable liquid crystal composition, aligning the liquid crystal molecules with the alignment layer, and curing. The film thickness and the formation method of the retardation layer can be the same as those of a general retardation layer.

3. A phase difference plate A conductive layer may be formed between the substrate and the alignment layer. In addition, since it described in the said "C. board | substrate with an orientation layer" about the conductive layer, description here is abbreviate | omitted.
The phase difference plate may or may not have flexibility.

4). Method for Producing Retardation Plate A method for producing a phase difference plate according to the present invention comprises applying a thermosetting composition having a photo-alignment property according to the present invention on a substrate to form a thermosetting property having the photo-alignment property. Forming a coating film of the composition and forming a cured film by heating the coating film; and
Forming an alignment layer by irradiating the cured film with polarized ultraviolet rays;
On the alignment layer, a polymerizable liquid crystal composition having an ethylenically unsaturated double bond group is applied to form a coating film of the polymerizable liquid crystal composition, and the coating film is a phase of the polymerizable liquid crystal composition. Aligning liquid crystal molecules with the alignment layer by heating to a transition temperature;
And a step of forming a retardation layer by irradiating light onto the coating film of the polymerizable liquid crystal composition in which the liquid crystal molecules are aligned.
In the method for producing a retardation plate according to the present invention, the step of forming a cured film and the step of forming an alignment layer are described in the above “C. Substrate with alignment layer”, and thus the description thereof is omitted here. .

  In the step of aligning liquid crystal molecules, a method of forming a coating film of a polymerizable liquid crystal composition having an ethylenically unsaturated double bond group, a method of heating to a phase transition temperature, a conventionally known method may be used, There is no particular limitation. As for the coating method and the heating method, the same method as in the alignment layer forming step can be used.

  The coating film of the polymerizable liquid crystal composition in which the liquid crystal molecules are aligned causes a polymerization reaction by irradiating with light, and an ethylenically unsaturated double bond group contained in the polymerizable liquid crystal compound contained in the retardation layer. Alternatively, the ethylenically unsaturated double bond groups of the polymerizable liquid crystal compound contained in the retardation layer and the ethylenically unsaturated double bond group of the compound containing the aromatic hydrocarbon group in the alignment layer are polymerized. A conventionally known method may be used as the light irradiation method. As the light irradiation method, ultraviolet irradiation is preferably used.

  The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the present invention has substantially the same configuration as the technical idea described in the claims of the present invention, and any device that exhibits the same function and effect is the present invention. It is included in the technical scope of the invention.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples.
[Synthesis Example 1] Synthesis of Photoalignment Monomer 1 Photoalignment monomer 1 was synthesized as shown in the following scheme in the same manner as Synthesis Example 1 of Japanese Patent No. 5668881.

[Synthesis Example 2] Synthesis of Photoalignment Monomer 2 Photoalignment monomer 2 was synthesized as shown in the following scheme in the same manner as in Synthesis Example 3 of Japanese Patent No. 5626492.

Synthesis Example 3 Synthesis of Thermally Crosslinkable Monomer 2 Thermally crosslinkable monomer 2 was synthesized as shown in the following scheme in the same manner as in Synthesis Example 5 of Japanese Patent No. 5668881.

The structure of each monomer used for the synthesis of the following copolymer is shown in Table 1 below.
Each synthesized monomer was confirmed for its chemical structure by ¹ H NMR measurement using JEOL JNM-LA400WB manufactured by JEOL Ltd.

[Production Example 1] Synthesis of copolymer 1 4.2 g of photoalignable monomer 1, 1.4 g of thermally crosslinkable monomer 1 (hydroxybutyl acrylate), α, α′-azobisisobutyronitrile (AIBN) as a polymerization catalyst 50 mg was dissolved in 25 ml of dioxane and reacted at 90 ° C. for 6 hours. After completion of the reaction, the copolymer 1 was obtained by purification by a reprecipitation method. The number average molecular weight of the obtained copolymer 1 was 21300.
The number average molecular weight (hereinafter referred to as Mn) of each copolymer synthesized was determined by gel permeation chromatography using HLC-8220 GPC manufactured by Tosoh Corporation with polystyrene as a standard substance and NMP as an eluent. GPC).

[Production Example 2] Synthesis of Copolymer 2 Copolymer 2 was synthesized in the same manner as Production Example 1 except that 3.1 g of photo-alignment monomer 2 and 1.9 g of thermally crosslinkable monomer 2 were used. The number average molecular weight of the obtained copolymer 2 was 19400.

[Example 1]
(Preparation of thermosetting composition 1)
A thermosetting composition 1 having the following composition was prepared. As the thermally crosslinkable polymerizable compound 1 containing an aromatic hydrocarbon group, the compounds shown in Table 2 below were prepared.
-Copolymer 1: 0.1 g
-Hexamethoxymethylmelamine (HMM): 0.01 g
-Thermally crosslinkable polymerizable compound 1: 0.01 g
-P-Toluenesulfonic acid monohydrate (PTSA): 0.0015 g
Propylene glycol monomethyl ether (PGME): 2g

(Formation of alignment layer)
The said thermosetting composition was apply | coated to one surface of the transparent glass substrate by spin coating, and it heat-dried in 100 degreeC oven for 1 minute, the cured film was formed, and the coating film was obtained. An alignment layer was formed by irradiating the cured film surface with polarized ultraviolet rays containing a 313 nm emission line in a direction perpendicular to the substrate normal by 20 mJ / cm ² using a Hg—Xe lamp and a Grand Taylor prism.

(Production of retardation plate)
5% by mass of BASF Corporation photopolymerization initiator Irgacure 184 is added to a solution in which a liquid crystalline monomer represented by the following formula is dissolved in cyclohexanenon so as to have a solid content of 15% by mass. Was prepared.

The polymerizable liquid crystal composition was applied to the surface of the transparent glass substrate on which the alignment layer was formed by spin coating, and heated in a 70 ° C. oven for 1 minute to form a coating film. A retardation plate was produced by irradiating the surface of the polymerizable liquid crystal composition coated with 300 mJ / cm ² of non-polarized ultraviolet light containing a 365 nm emission line using a Hg—Xe lamp in a nitrogen atmosphere.

[Examples 2 to 16 and Comparative Examples 1 to 3]
Copolymers 1-2, hexamethoxymethylmelamine (HMM) as a crosslinking agent, p-toluenesulfonic acid monohydrate (PTSA) as an acid or acid generator, thermally crosslinkable polymerizable compounds 1-4 and comparative thermal crosslinking The heat of Examples 2-16 and Comparative Examples 1-3, as in Example 1, using polymerizable polymerizable compounds C1-C2, propylene glycol monomethyl ether (PGME) as solvent, and optionally photoinitiator 1-2. A curable composition was prepared, an alignment layer was formed, and a retardation plate was produced.
Photoinitiators 1 and 2 are as shown below.
Photoinitiator 1: 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide (Irgacure TPO BASF)
Photoinitiator 2: Ethanone, 1- [9-ethyl-6- (2-methylbenzoyl) -9H-carbazol-3-yl]-, 1- (0-acetyloxime) (Irgacure OXE-02 manufactured by BASF)
The composition of each thermosetting composition is shown in Table 3 below.

[Evaluation]
The following evaluation was performed about each obtained thermosetting composition and each phase difference plate.

(Liquid crystal orientation)
Two linearly polarizing plates were placed in a crossed Nicol state, a retardation plate was sandwiched between them, and the samples were visually observed. When the substrate is rotated, “A” indicates that the bright and dark pattern observed in the plane is clear, and “B” indicates that the bright and dark pattern observed in the plane is clear but the orientation is weak. Those with defects were evaluated as “C”. Here, the weak orientation means a case where it is partially gray or not uniform.

(Adhesion)
A 10 × 10 lattice pattern was formed on the phase difference plate by using an equally spaced spacer and cutting with a cutter knife at 1 mm intervals. Subsequently, the cellophane tape was placed on the lattice pattern and brought into close contact, and then the cellophane tape was peeled off. The cut part of the coating film after peeling off the cellophane tape was observed. A case where the number of lattice meshes where peeling occurs at a point where the coating film crosses or intersects the cut line is less than 5% with respect to the total number of lattice patterns is defined as “A”, and 5% or more and 10 The case of less than% was designated as “B”, and the case of 10% or more was designated as “C”.

(Durable adhesion 1 after 48 hours storage)
After the retardation film was stored in an oven at a temperature of 60 ° C. and a humidity of 90% for 48 hours, the durability adhesion was evaluated by the same evaluation method as the above adhesion. A case where the number of lattice meshes where peeling occurs at a point where the coating film crosses or intersects the cut line is less than 5% with respect to the total number of lattice patterns is defined as “A”, and 5% or more and 10 The case of less than% was designated as “B”, and the case of 10% or more was designated as “C”.

(Durable adhesion 2 after 96 hours storage)
The retardation film was stored in an oven at a temperature of 60 ° C. and a humidity of 90% for 96 hours, and then durability adhesion was evaluated by the same evaluation method as the above adhesion. A case where the number of lattice meshes where peeling occurs at a point where the coating film crosses or intersects the cut line is less than 5% with respect to the total number of lattice patterns is defined as “A”, and 5% or more and 10 The case of less than% was designated as “B”, and the case of 10% or more was designated as “C”.

Claims (8)

A copolymer having a photoalignable structural unit and a thermally crosslinkable structural unit;
A crosslinking agent that binds to the thermally crosslinkable group of the thermally crosslinkable structural unit;
A compound having at least one of a hydroxy group and a carboxy group, an aromatic hydrocarbon group, and an ethylenically unsaturated double bond group;
A thermosetting composition having a photo-alignment property, comprising:   The thermosetting composition having photo-alignment property according to claim 1, further comprising a photoinitiator. The said photoalignment structural unit contains the photoalignment structural unit represented by following formula (1), The thermosetting composition which has a photoalignment of Claim 1 or 2 characterized by the above-mentioned.
(Wherein, in formula (1), X is a photo-alignment group, L ¹ is a divalent linking group or single bond, R ¹ is a hydrogen atom, methyl group, chlorine atom or phenyl group, k is 1-5. Represents.) A photodimerization structure or photoisomerization structure of a photoalignable group possessed by the photoalignable structural unit, and a copolymer having a crosslinked structure formed by bonding a thermally crosslinkable group possessed by the thermally crosslinkable structural unit and a crosslinking agent; ,
A compound having a crosslinked structure formed by bonding at least one of a hydroxy group and a carboxy group and a crosslinking agent, an aromatic hydrocarbon group, and an ethylenically unsaturated double bond group;
An alignment layer comprising:   A substrate with an alignment layer, comprising: a substrate; and the alignment layer according to claim 4 disposed on the substrate. On the board | substrate, the thermosetting composition which has the photo-alignment property of any one of Claims 1-3 is apply | coated, the coating film of the thermosetting composition which has the said photo-alignment property is formed, The said Forming a cured film by heating the coating film;
And a step of forming an alignment layer by irradiating the cured film with polarized ultraviolet rays. A substrate,
A photo-dimerization structure or photo-isomerization structure of a photo-alignment group of a photo-alignment constituent unit, and a heat-crosslinkable group of a heat-cross-linkable constitution unit and a cross-linking agent, which are arranged on the substrate, are combined. It has a structure in which a copolymer having a crosslinked structure, a crosslinked structure formed by bonding at least one of a hydroxy group and a carboxy group and a crosslinking agent, an aromatic hydrocarbon group, and an ethylenically unsaturated double bond group are polymerized. An alignment layer containing a compound;
A retardation layer having a structure in which an ethylenically unsaturated double bond group of the polymerizable liquid crystal composition having an ethylenically unsaturated double bond group disposed on the alignment layer is polymerized. Phase difference plate. On the board | substrate, the thermosetting composition which has the photo-alignment property of any one of Claims 1-3 is apply | coated, the coating film of the thermosetting composition which has the said photo-alignment property is formed, The said Forming a cured film by heating the coating film;
Forming an alignment layer by irradiating the cured film with polarized ultraviolet rays;
On the alignment layer, a polymerizable liquid crystal composition having an ethylenically unsaturated double bond group is applied to form a coating film of the polymerizable liquid crystal composition, and the coating film is a phase of the polymerizable liquid crystal composition. Aligning liquid crystal molecules with the alignment layer by heating to a transition temperature;
And a step of forming a retardation layer by irradiating light onto the coating film of the polymerizable liquid crystal composition in which the liquid crystal molecules are aligned.