JP2024037943A - Manufacturing method of liquid crystal orientation film, liquid crystal orientation film and liquid crystal display - Google Patents

Abstract

To provide a manufacturing method of forming a plurality of areas having different orientation directions (orientation division) and thereby easily forming a VA mode liquid crystal display element excellent in field of view angle.SOLUTION: The manufacturing method of multi-domain liquid crystal orientation film includes: a step of applying on a substrate liquid crystal orientation agent that contains polymer including optical orientation group and thermal cross-linking group A as component (A) and solvent, and satisfies at least one of the following Z1 and Z2, to form a cured film; a first irradiation step of irradiating the cured film with ultraviolet from an oblique direction; and a second irradiation step of irradiating the cured film subjected to the ultraviolet irradiation with ultraviolet from a direction different from the first irradiation step, in this order. At least one of the irradiation steps is performed via a mask including a light-shielded area and a not light-shielded area. Z1: the component (A) further contains thermal cross-linking group B. Z2: the component (B) further contains compound containing thermal cross-linking group B.SELECTED DRAWING: Figure 1

Description

The present invention relates to a method for producing a liquid crystal alignment film using a liquid crystal alignment agent, a liquid crystal alignment film obtained thereby, and a liquid crystal display element equipped with the obtained liquid crystal alignment film. More specifically, by using a specific liquid crystal aligning agent, even when the firing temperature is low and the firing time is short, the liquid crystal alignment property is good, the pretilt angle expression ability is excellent, and the reliability is high. The present invention relates to a method for producing a multi-domain liquid crystal aligning film with excellent display quality, a multi-domain liquid crystal aligning film, and a liquid crystal display element using a liquid crystal aligning film that can be obtained and overwriting the pretilt angle, and a specific liquid crystal aligning agent.

In a liquid crystal display element, a liquid crystal alignment film plays the role of aligning liquid crystal in a certain direction. Currently, the main liquid crystal alignment films used industrially are polyimide precursors such as polyamic acid (also called polyamic acid), polyamic acid esters, and polyimide-based liquid crystal alignment agents made of polyimide solutions, which are applied to a substrate. It is manufactured by coating and forming a film.
In addition, when the liquid crystal is aligned parallel or oblique to the substrate surface, a surface stretching process by rubbing is further performed after the film is formed.

On the other hand, when aligning liquid crystal perpendicularly to the substrate (referred to as vertical alignment (VA) method), long-chain alkyls, cyclic groups, or combinations of cyclic groups and alkyl groups (for example, see Patent Document 1), steroid skeletons ( For example, a liquid crystal alignment film is used in which a hydrophobic group such as (see Patent Document 2) is introduced into the side chain of polyimide. In this case, when applying a voltage between the substrates and tilting the liquid crystal molecules in a direction parallel to the substrates, it is necessary to make sure that the liquid crystal molecules tilt from the normal direction of the substrates to one direction within the plane of the substrates. . Methods for this purpose include, for example, providing protrusions on the substrate, providing slits in the display electrodes, and rubbing to slightly tilt the liquid crystal molecules from the normal direction of the substrate toward one direction within the substrate surface. Furthermore, the liquid crystal can be pretilted by adding a photopolymerizable compound to the liquid crystal composition in advance, using it together with a vertical alignment film such as polyimide, and irradiating the liquid crystal cell with ultraviolet rays while applying a voltage. A method (for example, see Patent Document 3) has been proposed.

In recent years, as an alternative to the formation of protrusions and slits in VA liquid crystal alignment control, and the PSA technique, methods (photoalignment methods) that utilize anisotropic photochemical reactions such as polarized ultraviolet irradiation have also been proposed. In other words, it is known that by irradiating a photoreactive, vertically aligned polyimide film with polarized ultraviolet rays to impart alignment regulation ability and pretilt angle development ability, it is possible to uniformly control the tilt direction of liquid crystal molecules when voltage is applied. (See Patent Document 4). In this case as well, a polyimide-based liquid crystal alignment film is used, which has excellent durability and is suitable for controlling the pretilt angle of the liquid crystal, like the conventional alignment film. Polyimide-based liquid crystal alignment films are generally fired at a high temperature of 200° C. or higher.

On the other hand, efforts are being made to use thin and lightweight plastic substrates as substrates for liquid crystal display elements. In this case, since the heat resistance of the plastic substrate is low, it is necessary to perform baking at a lower temperature when producing the liquid crystal alignment film. Similarly, it is also desired to reduce the energy cost in manufacturing liquid crystal display elements by lowering the firing temperature.

When baking at a low temperature, there is a problem that curing must be completed before the alignment film material is sufficiently cured, making it difficult to obtain a highly reliable liquid crystal display element (for example, (See Patent Document 5).

On the other hand, there is an increasing demand for multi-domain technology that forms multiple regions with different orientation directions (orientation division). After that, it is necessary to shift the exposure mask by a predetermined interval and expose again, and high precision is required for alignment of the exposure mask and formation of multiple openings, making the manufacturing process complicated, and improvements are needed. . Here, a method for manufacturing a multi-domain liquid crystal display element using a polymer in which a vertical alignment group is bonded to a photodegradable polyimide is known, but it requires a very large amount of light irradiation and has poor manufacturing efficiency ( For example, see Patent Documents 6, 7, and 8). Although there are further examples of methods for producing multi-domain alignment films, it has not been clear what kind of alignment film should be used to enable the invention to be implemented (for example, see Patent Document 9).

Japanese Patent Application Publication No. 3-179323 Japanese Patent Application Publication No. 4-281427 Patent No. 4504626 Patent No. 4995267 Japanese Patent Application Publication No. 7-209633 Japanese Patent Application Publication No. 11-95224 Japanese Patent Application Publication No. 2005-148442 Japanese Patent Application Publication No. 2005-316027 Japanese Patent Application Publication No. 2007-219191

An object of the present invention is to provide a VA mode liquid crystal display element that more easily forms a plurality of regions with different orientation directions (orientation division) with fewer mask processing steps and has excellent viewing angle characteristics, and a method for manufacturing the same. do.
In addition to the above-mentioned objects, it is an object of the present invention to provide an ECB liquid crystal display element having improved viewing angle characteristics and a liquid crystal alignment film for the element.

The present inventors have discovered the invention whose gist is <X> below.
<X> Contains a polymer having a photo-alignable group and a thermally crosslinkable group A represented by the following formula (pa-1) and a solvent as the component (A), and satisfies at least one of the following requirements Z1 and Z2. a step of applying a liquid crystal aligning agent that satisfies the requirements on the substrate and forming a cured film by drying and baking;
A first irradiation step of irradiating the cured film with ultraviolet rays from an oblique direction, and
A second irradiation step of irradiating the cured film with ultraviolet rays from a direction different from that of the first irradiation step in this order,
A method for manufacturing a multi-domain liquid crystal alignment film, characterized in that at least one of the first irradiation step and the second irradiation step is performed through a mask including a light-blocked region and a non-light-blocked region. .
Z1: The polymer that is component (A) further has a thermally crosslinkable group B.
Z2: Further contains a compound having two or more thermally crosslinkable groups B in the molecule as component (B).

In the formula, A is optionally a group selected from fluorine, chlorine, cyano, or an alkoxy group having 1 to 5 carbon atoms, a linear or branched alkyl residue (which can optionally be one pyrimidine-2,5-diyl, pyridine-2,5-diyl, 2,5-thiophenylene, 2,5-furanylene, substituted with a cyano group or one or more halogen atoms); Represents 1,4- or 2,6-naphthylene or phenylene, R ₁ is a single bond, oxygen atom, -COO- or -OCO-, and R ₂ is a divalent aromatic group, a divalent alicyclic group group, a divalent heterocyclic group, or a divalent fused cyclic group, R ₃ is a single bond, an oxygen atom, -COO- or -OCO-, and R ₄ is a straight chain having 1 to 40 carbon atoms. or a monovalent organic group having 3 to 40 carbon atoms containing a branched alkyl group or alicyclic group, and D is an oxygen atom, a sulfur atom, or -NR _d - (where R _d is a hydrogen atom or represents an alkyl having 1 to 3 carbon atoms), a is an integer of 0 to 3, and * represents a bonding position.
Thermal crosslinkable group A and thermally crosslinkable group B each independently include a carboxyl group, an amino group, an alkoxymethylamide group, a hydroxymethylamide group, a hydroxyl group, an epoxy site-containing group, an oxetanyl group, a thiiranyl group, an isocyanate group, and a block. An organic group selected from the group consisting of isocyanate groups, which is selected such that thermally crosslinkable group A and thermally crosslinkable group B undergo a crosslinking reaction with heat, provided that thermally crosslinkable group A and thermally crosslinkable group The groups B may be the same.

According to the present invention, it is possible to more easily form a plurality of regions having different orientation directions (orientation division) with fewer mask processing steps, and provide a VA mode liquid crystal display element with excellent viewing angle characteristics.

It is a schematic diagram showing the irradiation process of the present invention. Θ represents the irradiation angle in the first irradiation step, Φ represents the irradiation angle in the second irradiation step, and Ψ represents the tilt angle.

The method for producing a multi-domain liquid crystal alignment film of the present invention comprises as component (A) a polymer having a photoalignable group represented by the above formula (pa-1) and a thermally crosslinkable group A, and a solvent. , a step of applying a liquid crystal aligning agent that satisfies at least one of the following requirements Z1 and Z2 onto a substrate, and forming a cured film by drying and baking;
A first irradiation step of irradiating the cured film with ultraviolet rays from an oblique direction, and
A second irradiation step of irradiating the cured film with ultraviolet rays from a direction different from that of the first irradiation step in this order,
A method for manufacturing a multi-domain liquid crystal alignment film, characterized in that at least one of the first irradiation step and the second irradiation step is performed through a mask including a light-blocked region and a non-light-blocked region. .
Z1: The polymer that is component (A) further has a thermally crosslinkable group B.
Z2: Further contains a compound having two or more thermally crosslinkable groups B in the molecule as component (B).
Thermal crosslinkable group A and thermally crosslinkable group B each independently include a carboxyl group, an amino group, an alkoxymethylamide group, a hydroxymethylamide group, a hydroxyl group, an epoxy site-containing group, an oxetanyl group, a thiiranyl group, an isocyanate group, and a block. An organic group selected from the group consisting of isocyanate groups, which is selected such that thermally crosslinkable group A and thermally crosslinkable group B undergo a crosslinking reaction with heat, provided that thermally crosslinkable group A and thermally crosslinkable group The groups B may be the same.

Here, "two or more groups in the molecule" refers to cases in which the molecule contains two or more groups of the same type, such as two or more epoxy groups, as well as cases in which the molecule contains two or more groups of the same type, such as a combination of an epoxy group and a thiirane group. This also includes cases where the molecule contains a total of two or more different groups. "Two or more groups in the molecule" preferably means that the molecule contains two or more groups of the same type.

Since the polymer that is component (A) contained in the liquid crystal aligning agent of the present invention has high sensitivity to light, it can exhibit alignment control ability even when irradiated with polarized ultraviolet light at a low exposure dose.

In addition, since the polymer that is the component (A) contains the thermally crosslinkable group A and further contains the thermally crosslinkable group B in the component, the component (A) can be used even when the baking time of the liquid crystal aligning agent is short. It becomes possible to carry out crosslinking reactions involving polymers that are This makes it easier for the anisotropy to remain (memory) in the liquid crystal alignment film when the photoalignment site develops anisotropy due to a photoreaction, thereby increasing the liquid crystal alignment and developing the pretilt angle of the liquid crystal. It becomes possible to do so.

In addition, the site having the photoalignable group represented by the above formula (pa-1) (for example, the group represented by the below-mentioned formula (a-1)), the thermally crosslinkable group A, and the thermally crosslinkable group B are Since any of these can become side chains in a polymer, they can also be referred to as "side chains" if necessary.
Each component of the present invention will be explained in detail below.

<(A) component: specific polymer>
[Photoalignable group represented by formula (pa-1)]
In the present invention, the site in the molecule having the photo-alignment property represented by the above formula (pa-1) can be represented by, for example, the following formula (a-1). Further, the site may include, but is not limited to, a structure derived from a monomer represented by the following formula (a-1-m). In the formula, I _a is a monovalent organic group represented by the following formula (pa-1).

In formula (pa-1), A is optionally a group selected from fluorine, chlorine, cyano, an alkoxy group having 1 to 5 carbon atoms, a linear or branched alkyl residue (this is pyrimidine-2,5-diyl, pyridine-2,5-diyl, 2,5-thiophenylene, optionally substituted with one cyano group or one or more halogen atoms) , 5-furanylene, 1,4- or 2,6-naphthylene or phenylene, R ₁ is a single bond, oxygen atom, -COO- or -OCO-, R ₂ is a divalent aromatic group, 2 a valent alicyclic group, a divalent heterocyclic group, or a divalent fused cyclic group, R ₃ is a single bond, an oxygen atom, -COO- or -OCO-, and R ₄ has a carbon number of 1 -40 linear or branched alkyl group or alicyclic group, and D is a monovalent organic group having 3 to 40 carbon atoms, and D is an oxygen atom, a sulfur atom, or -NR _d - (here, R _d represents a hydrogen atom or an alkyl having 1 to 3 carbon atoms), a is an integer of 0 to 3, and * represents the bonding position with _Sa.

In the above formula (a-1) or (a-1-m), S _a represents a spacer unit, and the bonding group on the left of S _a is optionally attached to the main chain of the first and second specific polymers. This shows that they are bonded to each other through a spacer.

S _a can be represented, for example, by the structure of the following formula (Sp).

In the formula (Sp),
The left bond of W ₁ represents the bond to M _b ,
The bond to the right of W ₃ represents the bond to I _a ,
W ₁ , W ₂ and W ₃ each independently represent a single bond, a divalent heterocycle, -(CH ₂ ) _n - (in the formula, n represents 1 to 20), -OCH ₂ -, - Represents CH ₂ O-, -COO-, -OCO-, -CH=CH-, -CF=CF-, -CF ₂ O-, -OCF ₂ -, -CF ₂ CF ₂ - or -C≡C- However, in these substituents, one or more non-adjacent CH ₂ groups are independently -O-, -CO-, -CO-O-, -O-CO-, -Si(CH ₃ ) ₂ - O-Si(CH ₃ ) ₂ -, -NR-, -NR-CO-, -CO-NR-, -NR-CO-O-, -OCO-NR-, -NR-CO-NR-, -CH Substitution with =CH-, -C≡C- or -O-CO-O- (wherein R independently represents hydrogen or a straight or branched alkyl group having 1 to 5 carbon atoms) is possible,
A ₁ and A ₂ are each independently a group selected from a single bond, a divalent alkyl group, a divalent aromatic group, a divalent alicyclic group, or a divalent heterocyclic group; , each group may be unsubstituted or one or more hydrogen atoms may be substituted with a fluorine atom, chlorine atom, cyano group, methyl group or methoxy group.

In formula (a-1-m), M _a represents a polymerizable group. Examples of the polymerizable group include radically polymerizable groups of (meth)acrylate, fumarate, maleate, α-methylene-γ-butyrolactone, styrene, vinyl, maleimide, norbornene, (meth)acrylamide and its derivatives, and siloxane. can. Preferred are (meth)acrylate, α-methylene-γ-butyrolactone, styrene, vinyl, maleimide, and acrylamide.
r is an integer satisfying 1≦r≦3.

In formula (a-1-m), M _b represents a single bond, an (r+1)-valent heterocycle, a linear or branched alkyl group having 1 to 10 carbon atoms, an (r+1)-valent aromatic group, ( r+1) A group selected from valent alicyclic groups, each group being unsubstituted or having one or more hydrogen atoms substituted with a fluorine atom, chlorine atom, cyano group, methyl group or methoxy group. Also good.

Examples of the aromatic group for A ₁ , A _{2 ,} and M _b include aromatic hydrocarbons having 6 to 18 carbon atoms such as benzene, biphenyl, and naphthalene. Examples of the alicyclic group for A ₁ , A ₂ and M _b include alicyclic hydrocarbons having 6 to 12 carbon atoms such as cyclohexane and bicyclohexane. Examples of the heterocycle in A ₁ , A _{2 ,} and M _b include nitrogen-containing heterocycles such as pyridine, piperidine, and piperazine. Examples of the alkyl group for A ₁ and A ₂ include linear or branched alkyl groups having 1 to 10 carbon atoms.

From the viewpoint of achieving good vertical alignment control ability and a stable pretilt angle, the structure of (a-1) is a group represented by the above (pa-1) or the following (pa-1-a). Mention may be made of the groups represented. Further, the site may include, but is not limited to, a structure derived from a monomer represented by the following formula (pa-1-ma).

In formula (pa-1-a) or (pa-1-ma), M _a , M _b , and S _a have the same definitions as above.
Z is an oxygen atom or a sulfur atom.
X _a and X _b are each independently a hydrogen atom, a fluorine atom, a chlorine atom, a cyano group, or an alkyl group having 1 to 3 carbon atoms.
R ₁ is a single bond, an oxygen atom, -COO- or -OCO-.
R ₂ is a divalent aromatic group, a divalent alicyclic group, or a divalent heterocyclic group.
R ₃ is a single bond, an oxygen atom, -COO- or -OCO-.
R ₄ is a monovalent organic group having 3 to 40 carbon atoms containing a linear or branched alkyl group having 1 to 40 carbon atoms or an alicyclic group.
R ₅ is an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a fluorine atom or a cyano group, preferably a methyl group, a methoxy group or a fluorine atom.
a is an integer from 0 to 3, and b is an integer from 0 to 4.

In formula (pa-1-a) or (pa-1-ma), as the straight chain or branched alkylene group having 1 to 10 carbon atoms in S _a , straight chain or branched alkylene having 1 to 8 carbon atoms; It is preferably a group, such as a methylene group, an ethylene group, an n-propylene group, an n-butylene group, a t-butylene group, an n-pentylene group, an n-hexylene group, an n-heptylene group, or an n-octylene group. .

Examples of the divalent aromatic group of S _a include 1,4-phenylene group, 2-fluoro-1,4-phenylene group, 3-fluoro-1,4-phenylene group, 2,3,5,6-tetra Examples include fluoro-1,4-phenylene group.

Examples of the divalent alicyclic group of S _a include trans-1,4-cyclohexylene and trans-trans-1,4-bicyclohexylene.

Examples of the divalent heterocyclic group of S _a include 1,4-pyridylene group, 2,5-pyridylene group, 1,4-furanylene group, 1,4-piperazine group, 1,4-piperidine group, etc. be able to.

S _a is preferably an alkylene group having 1 to 8 carbon atoms, more preferably an alkylene group having 1 to 6 carbon atoms, and even more preferably an alkylene group having 1 to 4 carbon atoms.

Examples of the divalent aromatic group for R ₂ include 1,4-phenylene group, 2-fluoro-1,4-phenylene group, 3-fluoro-1,4-phenylene group, 2,3,5,6-tetra Examples include fluoro-1,4-phenylene group and naphthylene group.

Examples of the divalent alicyclic group for R ₂ include trans-1,4-cyclohexylene and trans-trans-1,4-bicyclohexylene.

Examples of the divalent heterocyclic group for R ₂ include 1,4-pyridylene group, 2,5-pyridylene group, 1,4-furanylene group, 1,4-piperazine group, 1,4-piperidine group, etc. be able to.

R ₂ is preferably a 1,4-phenylene group, trans-1,4-cyclohexylene, or trans-trans-1,4-bicyclohexylene.

Examples of the straight-chain or branched alkyl group having 1 to 40 carbon atoms for R ₄ include straight-chain or branched alkyl groups having 1 to 20 carbon atoms, and some of the hydrogen atoms of this alkyl group Alternatively, all of them may be substituted with fluorine atoms. Examples of such alkyl groups include methyl group, ethyl group, n-propyl, n-butyl group, t-butyl group, n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group, n- -nonyl group, n-decyl group, n-lauryl group, n-dodecyl group, n-tridecyl group, n-tetradecyl group, n-pentadecyl group, n-hexadecyl group, n-heptadecyl group, n-octadecyl group, n -nonadecyl group, n-eicosyl group, 4,4,4-trifluorobutyl group, 4,4,5,5,5-pentafluoropentyl, 4,4,5,5,6,6,6-heptafluoro Hexyl group, 3,3,4,4,5,5,5-heptafluoropentyl group, 2,2,2-trifluoroethyl group, 2,2,3,3,3-pentafluoropropyl group, 2- Examples include (perfluorobutyl)ethyl group, 2-(perfluorooctyl)ethyl group, and 2-(perfluorodecyl)ethyl group.

Examples of the monovalent organic group having 3 to 40 carbon atoms containing an alicyclic group for R ₄ include a cholestenyl group, a cholestanyl group, an adamantyl group, and the following formula (Alc-1) or (Alc-2) (in the formula, R ₇ is a hydrogen atom, a fluorine atom, or an alkyl group having 1 to 20 carbon atoms, and the alkyl group having 1 to 20 carbon atoms may be substituted with a fluorine atom, and * indicates the bonding position). The groups represented can be mentioned.

Examples of the monomer represented by the above formula (pa-1-ma) include, but are not limited to, structures represented by formulas (paa-1-ma1) to (paa-1-ma18). In the formula, "E" represents the E form, and "t" represents the trans form of the cyclohexyl group.

[Thermal crosslinkable group A and thermally crosslinkable group B]
Thermal crosslinkable group A and thermally crosslinkable group B each independently include a carboxyl group, an amino group, an alkoxymethylamide group, a hydroxymethylamide group, a hydroxyl group, an epoxy site-containing group, an oxetanyl group, a thiiranyl group, an isocyanate group, and a block. An organic group selected from the group consisting of isocyanate groups, which is selected such that thermally crosslinkable group A and thermally crosslinkable group B undergo a crosslinking reaction with heat, provided that thermally crosslinkable group A and thermally crosslinkable group The groups B may be the same.

Combinations of such thermally crosslinkable group A and thermally crosslinkable group B include combinations in which one is a carboxyl group and the other is an epoxy group, oxetanyl group, or thiiranyl group, and combinations in which one is a hydroxy group and the other is a blocked isocyanate group, one is a phenolic hydroxy group and the other is an epoxy group, oxetanyl group, or thiiranyl group, one is a carboxyl group and the other is a blocked isocyanate group, one is an amino group, and the other is a blocked isocyanate group, and both are N-alkoxymethylamide groups. More preferred combinations include a carboxyl group and an epoxy group, a hydroxy group and a blocked isocyanate group, and the like.

In order to introduce such a thermally crosslinkable group A into the polymer serving as component (A), a monomer having a thermally crosslinkable group A may be copolymerized.

In addition, when the liquid crystal aligning agent used in the present invention satisfies requirement Z1, when producing the polymer as component (A), a monomer having a thermally crosslinkable group A and a monomer having a thermally crosslinkable group B are added. Both may be copolymerized.

Examples of monomers having a thermally crosslinkable group include acrylic acid, methacrylic acid, crotonic acid, mono-(2-(acryloyloxy)ethyl)phthalate, mono-(2-(methacryloyloxy)ethyl)phthalate, N-( Monomers having a carboxyl group such as carboxyphenyl)maleimide, N-(carboxyphenyl)methacrylamide, and N-(carboxyphenyl)acrylamide;

2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, 4-hydroxybutyl acrylate, 4-hydroxybutyl methacrylate, 2,3-dihydroxypropyl acrylate, 2,3-dihydroxypropyl Methacrylate, diethylene glycol monoacrylate, diethylene glycol monomethacrylate, caprolactone 2-(acryloyloxy) ethyl ester, caprolactone 2-(methacryloyloxy) ethyl ester, poly(ethylene glycol) ethyl ether acrylate, poly(ethylene glycol) ethyl ether methacrylate, 5- Monomers having a hydroxy group such as acryloyloxy-6-hydroxynorbornene-2-carboxylic-6-lactone and 5-methacryloyloxy-6-hydroxynorbornene-2-carboxylic-6-lactone;

Monomers having a phenolic hydroxy group such as hydroxystyrene, N-(hydroxyphenyl)methacrylamide, N-(hydroxyphenyl)acrylamide, N-(hydroxyphenyl)maleimide, and N-(hydroxyphenyl)maleimide;

Monomers having an amino group such as aminoethyl acrylate, aminoethyl methacrylate, aminopropyl acrylate, and aminopropyl methacrylate;

N-hydroxymethyl (meth)acrylamide, N-methoxymethyl (meth)acrylamide, N-ethoxymethyl (meth)acrylamide, N-butoxymethyl (meth)acrylamide, etc. ) acrylamide compound;

Allyl glycidyl ether, glycidyl acrylate, glycidyl methacrylate, 2-methylglycidyl methacrylate, α-ethyl glycidyl acrylate, α-n-propylacrylate glycidyl, α-n-butyl glycidyl acrylate, 3,4-acrylate Epoxybutyl, 3,4-epoxybutyl methacrylate, 6,7-epoxyheptyl acrylate, 6,7-epoxyheptyl methacrylate, α-ethyl acrylate-6,7-epoxyheptyl, o-vinylbenzyl glycidyl ether, m-vinylbenzyl glycidyl ether, p-vinylbenzyl glycidyl ether, 3,4-epoxycyclohexylmethyl methacrylate, 3-ethenyl-7-oxabicyclo[4.1.0]heptane, 1,2-epoxy-5- Monomers having epoxy moiety-containing groups such as hexene and 1,7-octadiene monoepoxide;

3-(acryloyloxymethyl)oxetane, 3-(acryloyloxymethyl)-2-methyloxetane, 3-(acryloyloxymethyl)-3-ethyloxetane, 3-(acryloyloxymethyl)-2-trifluoromethyloxetane, 3-(acryloyloxymethyl)-2-pentafluoroethyloxetane, 3-(acryloyloxymethyl)-2-phenyloxetane, 3-(acryloyloxymethyl)-2,2-difluorooxetane, 3-(acryloyloxymethyl) -2,2,4-trifluorooxetane, 3-(acryloyloxymethyl)-2,2,4,4-tetrafluorooxetane, 3-(2-acryloyloxyethyl)oxetane, 3-(2-acryloyloxyethyl) )-2-ethyloxetane, 3-(2-acryloyloxyethyl)-3-ethyloxetane, 3-(2-acryloyloxyethyl)-2-trifluoromethyloxetane, 3-(2-acryloyloxyethyl)-2 -Pentafluoroethyloxetane, 3-(2-acryloyloxyethyl)-2-phenyloxetane, 3-(2-acryloyloxyethyl)-2,2-difluorooxetane, 3-(2-acryloyloxyethyl)-2, Acrylic acid esters such as 2,4-trifluorooxetane, 3-(2-acryloyloxyethyl)-2,2,4,4-tetrafluorooxetane; 3-(methacryloyloxymethyl)oxetane, 3-(methacryloyloxymethyl) )-2-methyloxetane, 3-(methacryloyloxymethyl)-3-ethyloxetane, 3-(methacryloyloxymethyl)-2-trifluoromethyloxetane, 3-(methacryloyloxymethyl)-2-pentafluoroethyloxetane, 3-(methacryloyloxymethyl)-2-phenyloxetane, 3-(methacryloyloxymethyl)-2,2-difluorooxetane, 3-(methacryloyloxymethyl)-2,2,4-trifluorooxetane, 3-(methacryloyl oxymethyl)-2,2,4,4-tetrafluorooxetane, 3-(2-methacryloyloxyethyl)oxetane, 3-(2-methacryloyloxyethyl)-2-ethyloxetane, 3-(2-methacryloyloxyethyl) )-3-ethyloxetane, 3-(2-methacryloyloxyethyl)-2-trifluoromethyloxetane, 3-(2-methacryloyloxyethyl)-2-pentafluoroethyloxetane, 3-(2-methacryloyloxyethyl) -2-phenyloxetane, 3-(2-methacryloyloxyethyl)-2,2-difluorooxetane, 3-(2-methacryloyloxyethyl)-2,2,4-trifluorooxetane, 3-(2-methacryloyloxy Monomers having an oxetanyl group such as ethyl)-2,2,4,4-tetrafluorooxetane;

2,3-epithiopropyl acrylate or methacrylate, and 2- or 3- or 4-(β-epithiopropylthiomethyl) styrene, 2- or 3- or 4-(β-epithiopropyloxymethyl) styrene, Monomers having a thiiranyl group such as 2- or 3- or 4-(β-epithiopropylthio)styrene, 2- or 3- or 4-(β-epithiopropyloxy)styrene;

2-(0-(1'-methylpropylideneamino)carboxyamino)ethyl acrylate, 2-(3,5-dimethylpyrazolyl)carbonylamino)ethyl acrylate, 2-(0-(1'-methyl methacrylate) Examples include monomers having a blocked isocyanate group such as propylideneamino)carboxyamino)ethyl and 2-(3,5-dimethylpyrazolyl)carbonylamino)ethyl methacrylate. Note that (meth)acrylamide means both acrylamide and methacrylamide.

In addition, in the present invention, when obtaining a specific copolymer, a monomer having a photoalignable group represented by the above formula (a-1-m) and a thermally crosslinkable group A and, if necessary, a thermally crosslinkable In addition to the monomer having group B, other monomers that can be copolymerized with these monomers can also be used.

Specific examples of such other monomers include acrylic ester compounds, methacrylic ester compounds, maleimide compounds, acrylonitrile, maleic anhydride, styrene compounds, vinyl compounds, N-methoxymethyl (meth)acrylamide, N-butoxymethyl Examples include acrylamide compounds such as (meth)acrylamide and acrylamide, and monomers having a nitrogen-containing aromatic heterocyclic group and a polymerizable group.

Examples of acrylic ester compounds include methyl acrylate, ethyl acrylate, isopropyl acrylate, benzyl acrylate, naphthyl acrylate, anthryl acrylate, anthryl methyl acrylate, phenyl acrylate, 2,2,2-trifluoroethyl acrylate, and tert-butyl acrylate. Acrylate, cyclohexyl acrylate, isobornyl acrylate, 2-methoxyethyl acrylate, methoxytriethylene glycol acrylate, 2-ethoxyethyl acrylate, tetrahydrofurfuryl acrylate, 3-methoxybutyl acrylate, 2-methyl-2-adamantyl acrylate, 2- Examples include propyl-2-adamantyl acrylate, 8-methyl-8-tricyclodecyl acrylate, and 8-ethyl-8-tricyclodecyl acrylate.

Examples of methacrylic acid ester compounds include methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, hexadecyl methacrylate, octadecyl methacrylate, benzyl methacrylate, naphthyl methacrylate, anthryl methacrylate, anthryl methyl methacrylate, phenyl methacrylate, and 2,2,2-trimethacrylate. Fluoroethyl methacrylate, tert-butyl methacrylate, cyclohexyl methacrylate, isobornyl methacrylate, 2-methoxyethyl methacrylate, methoxytriethylene glycol methacrylate, 2-ethoxyethyl methacrylate, tetrahydrofurfuryl methacrylate, 3-methoxybutyl methacrylate, 2-methyl- Examples include 2-adamantyl methacrylate, 2-propyl-2-adamantyl methacrylate, 8-methyl-8-tricyclodecyl methacrylate, and 8-ethyl-8-tricyclodecyl methacrylate.

Examples of the (meth)acrylamide compound include acrylamide, methacrylamide, N-methylacrylamide, N,N-dimethylacrylamide, N,N-diethylacrylamide, and the like.

Examples of the vinyl compound include methyl vinyl ether, benzyl vinyl ether, vinylnaphthalene, vinyl carbazole, allyl glycidyl ether, and 3-ethenyl-7-oxabicyclo[4.1.0]heptane.

Examples of the styrene compound include styrene, methylstyrene, chlorostyrene, and bromostyrene.

Examples of the maleimide compound include maleimide, N-methylmaleimide, N-phenylmaleimide, and N-cyclohexylmaleimide.

The nitrogen-containing aromatic heterocycle has a structure selected from the group consisting of the following formulas [N-a] to [N-b] (wherein Z ₂ is a straight chain or branched alkyl group having 1 to 5 carbon atoms) It is preferable that the aromatic cyclic hydrocarbon contains at least one, preferably one to four.

Specifically, oxazole ring, thiazole ring, pyridine ring, pyrimidine ring, quinoline ring, 1-pyrazoline ring, isoquinoline ring, thiadiazole ring, pyridazine ring, triazine ring, pyrazine ring, phenanthroline ring, quinoxaline ring, benzothiazole ring, Examples include an oxadiazole ring and an acridine ring. Furthermore, the carbon atoms of these nitrogen-containing aromatic heterocycles may have a substituent containing a heteroatom. Among these, for example, a pyridine ring can be mentioned.

Examples of monomers having a nitrogen-containing aromatic heterocyclic group and a polymerizable group include 2-(2-pyridylcarbonyloxy)ethyl (meth)acrylate, 2-(3-pyridylcarbonyloxy)ethyl (meth)acrylate, 2 -(4-pyridylcarbonyloxy)ethyl (meth)acrylate, and the like.

The other monomers used in the present invention may be used alone, or two or more monomers may be used in combination.

The photoreactive moieties represented by the above formula (pa-1) contained in the polymer of the present invention may be used alone or in combination of two or more kinds.
The photoreactive site represented by the above formula (pa-1) is contained in a proportion of 5 to 50 mol%, 10 to 40 mol%, or 15 to 35 mol% of the total repeating units of the polymer that is component (A). It is preferable that

As the site having a thermally crosslinkable group to be contained in the polymer of the present invention, thermally crosslinkable group A may be used alone, or two or more types of sites containing thermally crosslinkable group A and thermally crosslinkable group B may be used in combination. It may also be used.
The amount of the site having a thermally crosslinkable group introduced is preferably 50 to 95 mol%, 60 to 90 mol%, or 65 to 85 mol% of the total repeating units of the polymer as component (A).

The content of the structure derived from the other monomers is preferably 0 to 40 mol%, 0 to 30 mol%, or 0 to 20 mol% of the total repeating units of the polymer as component (A).

<Method for producing specific polymer>
The specific polymer of component (A) contained in the liquid crystal aligning agent of the present invention is a monomer having a photoalignable group represented by the above formula (pa-1), a monomer having the above thermally crosslinkable group A, , and, if desired, by copolymerizing a monomer having the above thermally crosslinkable group B. Moreover, it can be copolymerized with the other monomers mentioned above.

The method for producing the specific polymer of component (A) in the present invention is not particularly limited, and any industrially used general-purpose method can be used. Specifically, it can be produced by cationic polymerization, radical polymerization, or anionic polymerization using vinyl groups of monomers. Among these, radical polymerization is particularly preferred from the viewpoint of ease of reaction control.
As the polymerization initiator for radical polymerization, known compounds such as radical polymerization initiators and reversible addition-fragmentation chain transfer (RAFT) polymerization reagents can be used.

A radical thermal polymerization initiator is a compound that generates radicals when heated above the decomposition temperature. Such radical thermal polymerization initiators include, for example, ketone peroxides (methyl ethyl ketone peroxide, cyclohexanone peroxide, etc.), diacyl peroxides (acetyl peroxide, benzoyl peroxide, etc.), hydroperoxides (peroxide Hydrogen, tert-butyl hydroperoxide, cumene hydroperoxide, etc.), dialkyl peroxides (di-tert-butyl peroxide, dicumyl peroxide, dilauroyl peroxide, etc.), peroxyketals (dibutyl peroxycyclohexane) ), alkyl peresters (peroxyneodecanoic acid tert-butyl ester, peroxypivalic acid tert-butyl ester, peroxy 2-ethylcyclohexanoic acid tert-amyl ester, etc.), persulfates (potassium persulfate, sodium persulfate, ammonium persulfate, etc.), and azo compounds (azobisisobutyronitrile, 2,2'-di(2-hydroxyethyl)azobisisobutyronitrile, etc.).
Such radical thermal polymerization initiators can be used alone or in combination of two or more.

The radical photopolymerization initiator is not particularly limited as long as it is a compound that initiates radical polymerization by light irradiation. Examples of such radical photopolymerization initiators include known compounds such as benzophenone, Michler's ketone, 4,4'-bis(diethylamino)benzophenone, xanthone, thioxanthone, and isopropylxanthone. These compounds may be used alone or in combination of two or more.
The radical polymerization method is not particularly limited, and emulsion polymerization, suspension polymerization, dispersion polymerization, precipitation polymerization, bulk polymerization, solution polymerization, etc. can be used.

The solvent used in the polymerization reaction of the specific polymer of component (A) is not particularly limited as long as it dissolves the produced polymer. Specific examples include the solvents described in the <Solvent> section below, such as N-alkyl-2-pyrrolidones, dialkylimidazolidinones, lactones, carbonates, ketones, and the formula (Sv-1). Examples include the compound represented by the formula (Sv-2), tetrahydrofuran, 1,4-dioxane, dimethylsulfone, dimethylsulfoxide, and the like.
These solvents may be used alone or in combination. Furthermore, even a solvent that does not dissolve the produced polymer may be mixed with the above-mentioned solvent and used as long as the produced polymer does not precipitate.
Further, in radical polymerization, oxygen in the solvent becomes a cause of inhibiting the polymerization reaction, so it is preferable to use an organic solvent that has been degassed to the extent possible.

The polymerization temperature during radical polymerization can be selected from any temperature in the range of 30 to 150°C, but is preferably in the range of 50 to 100°C. Further, the reaction can be carried out at any concentration, but the monomer concentration is preferably 1 to 50% by mass, more preferably 5 to 30% by mass. The initial stage of the reaction can be carried out at a high concentration, and then an organic solvent can be added.
In the above-mentioned radical polymerization reaction, if the ratio of the radical polymerization initiator to the monomer is large, the molecular weight of the obtained polymer will be small, and if it is small, the molecular weight of the obtained polymer will be large. The amount is preferably 0.1 to 10 mol% based on the monomer to be polymerized. Furthermore, various monomer components, solvents, initiators, etc. can be added during polymerization.

[Polymer recovery]
When recovering produced polymers from the reaction solution obtained by the above-described reaction, the reaction solution may be poured into a poor solvent to precipitate the polymers. Examples of the poor solvent used for precipitation include methanol, acetone, hexane, heptane, butyl cellosolve, heptane, ethanol, toluene, benzene, diethyl ether, methyl ethyl ether, water, and the like. The polymer precipitated in a poor solvent can be collected by filtration and then dried under normal pressure or reduced pressure, at room temperature or by heating. Furthermore, by repeating the procedure of redissolving the precipitated and collected polymer in an organic solvent and re-precipitating and collecting it 2 to 10 times, the amount of impurities in the polymer can be reduced. Examples of the poor solvent in this case include alcohols, ketones, hydrocarbons, etc. It is preferable to use three or more types of poor solvents selected from these, since the efficiency of purification will further increase.

The molecular weight of the specific polymer of component (A) is the weight average measured by GPC (Gel Permeation Chromatography) method, considering the strength of the resulting coating film, workability during coating film formation, and uniformity of the coating film. The molecular weight is preferably 2,000 to 1,000,000, more preferably 5,000 to 100,000.

<(B) component>
When the liquid crystal aligning agent used in the present invention satisfies requirement Z2, it contains a crosslinking agent as the component (B). Component (B) includes a crosslinking agent having two or more thermally crosslinkable groups B.

As the crosslinking agent which is component (B), low molecular weight compounds such as epoxy compounds, compounds having two or more amino groups, methylol compounds, isocyanate compounds, phenoplast compounds, blocked isocyanate compounds, and polymers of N-alkoxymethyl acrylamide are used. , a polymer of a compound having an epoxy group, a polymer of a compound having an isocyanate group, and the like.

Specific examples of the above-mentioned epoxy compounds include ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, 6-hexanediol diglycidyl ether, glycerin diglycidyl ether, 2,2-dibromoneopentyl glycol diglycidyl ether, 1,3,5,6-tetraglycidyl-2,4-hexanediol, N,N,N', N',-tetraglycidyl-m-xylene diamine, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, and N,N,N',N'-tetraglycidyl-4,4'-diaminodiphenylmethane etc.

Examples of compounds having two or more amino groups include diamines such as alicyclic diamines, aromatic diamines, aromatic-aliphatic diamines, and aliphatic diamines.

Examples of alicyclic diamines include 1,4-diaminocyclohexane, 1,3-diaminocyclohexane, 4,4'-diaminodicyclohexylmethane, 4,4'-diamino-3,3'-dimethyldicyclohexylamine, and isophorone. Examples include diamine.

Examples of aromatic diamines include o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, 2,4-diaminotoluene, 2,5-diaminotoluene, 3,5-diaminotoluene, 1,4-diamino Examples include -2-methoxybenzene, 2,5-diamino-p-xylene, and 1,3-diamino-4-chlorobenzene.

Examples of aromatic-aliphatic diamines include 3-aminobenzylamine, 4-aminobenzylamine, 3-amino-N-methylbenzylamine, 4-amino-N-methylbenzylamine, 3-aminophenethylamine, 4-aminobenzylamine, Aminophenethylamine, 3-amino-N-methylphenethylamine, 4-amino-N-methylphenethylamine, 3-(3-aminopropyl)aniline, 4-(3-aminopropyl)aniline, 3-(3-methylaminopropyl) Aniline, 4-(3-methylaminopropyl)aniline, 3-(4-aminobutyl)aniline, 4-(4-aminobutyl)aniline, 3-(4-methylaminobutyl)aniline, 4-(4-methyl) aminobutyl)aniline, 3-(5-aminopentyl)aniline, 4-(5-aminopentyl)aniline, 3-(5-methylaminopentyl)aniline, 4-(5-methylaminopentyl)aniline, 2-( Examples include 6-aminonaphthyl)methylamine, 3-(6-aminonaphthyl)methylamine, 2-(6-aminonaphthyl)ethylamine, and 3-(6-aminonaphthyl)ethylamine.

Examples of aliphatic diamines include 1,2-diaminoethane, 1,3-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane, 1,6-diaminohexane, and 1,7-diaminoheptane. , 1,8-diaminooctane, 1,9-diaminononane, 1,10-diaminodecane, 1,3-diamino-2,2-dimethylpropane, 1,6-diamino-2,5-dimethylhexane, 1,7 -diamino-2,5-dimethylheptane, 1,7-diamino-4,4-dimethylheptane, 1,7-diamino-3-methylheptane, 1,9-diamino-5-methylheptane and the like.

Specific examples of methylol compounds include compounds such as alkoxymethylated glycoluril, alkoxymethylated benzoguanamine, and alkoxymethylated melamine.

Specific examples of alkoxymethylated glycoluril include 1,3,4,6-tetrakis(methoxymethyl)glycoluril, 1,3,4,6-tetrakis(butoxymethyl)glycoluril, 1,3,4 , 6-tetrakis(hydroxymethyl)glycoluril, 1,3-bis(hydroxymethyl)urea, 1,1,3,3-tetrakis(butoxymethyl)urea, 1,1,3,3-tetrakis(methoxymethyl) Examples include urea, 1,3-bis(hydroxymethyl)-4,5-dihydroxy-2-imidazolinone, and 1,3-bis(methoxymethyl)-4,5-dimethoxy-2-imidazolinone. Commercially available products include compounds such as glycoluril compounds (product names: Cymel (registered trademark) 1170, Powder Link (registered trademark) 1174) manufactured by Mitsui Cytec Co., Ltd., and methylated urea resins (product name: UFR (registered trademark) 65). ), butylated urea resin (product name: UFR (registered trademark) 300, U-VAN10S60, U-VAN10R, U-VAN11HV), urea/formaldehyde resin manufactured by DIC Corporation (high condensation type, product name: Beckamine ( Examples include registered trademarks) J-300S, P-955, N), etc.

Specific examples of alkoxymethylated benzoguanamine include, for example, tetramethoxymethylbenzoguanamine. Commercially available products include Mitsui Cytec Co., Ltd. (product name: Cymel (registered trademark) 1123), Sanwa Chemical Co., Ltd. (product names: Nikalac (registered trademark) BX-4000, BX-37, and BL-). 60, BX-55H), etc.

Specific examples of alkoxymethylated melamine include hexamethoxymethylmelamine and the like. Commercially available products include methoxymethyl type melamine compounds (trade name: Cymel (registered trademark) 300, Cymel 301, Cymel 303, Cymel 350), butoxymethyl type melamine compounds (trade name: Mycoat (registered trademark)) manufactured by Mitsui Cytec Co., Ltd. ) 506, 508), methoxymethyl type melamine compounds manufactured by Sanwa Chemical (trade name: Nikalak (registered trademark) MW-30, Nikalak MW-22, Nikalak MW-11, Nikalak MS-001, Nikalak MX-002, Nikalak (registered trademark) MX-730, MX-750, MX-035), butoxymethyl type melamine compounds (trade name: Nikalac (registered trademark) MX-45, MX-410, MX-302), and the like.

It may also be a compound obtained by condensing a melamine compound, a urea compound, a glycoluril compound, and a benzoguanamine compound in which the hydrogen atom of the amino group is substituted with a methylol group or an alkoxymethyl group. Examples include high molecular weight compounds made from melamine and benzoguanamine compounds as described in US Pat. No. 6,323,310. Examples of commercial products of the melamine compound include the trade name Cymel (registered trademark) 303 (manufactured by Mitsui Cytec Co., Ltd.), and commercial products of the benzoguanamine compound include the trade name Cymel (registered trademark) 1123 (trade name). (manufactured by Mitsui Cytec Co., Ltd.), etc.

Specific examples of isocyanate compounds include VESTANAT B1358/100, VESTAGON BF 1540 (all of the above are isocyanurate-type modified polyisocyanates, manufactured by Degussa Japan Co., Ltd.), Takenate (registered trademark) B-882N, VESTAGON B-7075 ( Examples include isocyanurate-type modified polyisocyanate (manufactured by Mitsui Chemicals, Inc.).

Specific examples of the phenoplast compound include the following compounds, but the phenoplast compound is not limited to the following compound examples.

Specific examples of the compound having two or more hydroxyalkylamide groups at the end of the molecule include the following compounds, Primid XL-552, and Primid SF-4510.

Examples of the blocked isocyanate compound include Coronate AP Stable M, Coronate 2503, 2515, 2507, 2513, 2555, Millionate MS-50 (manufactured by Nippon Polyurethane Industry Co., Ltd.), Takenate B-830, B-815N, Examples include B-820NSU, B-842N, B-846N, B-870N, B-874N, and B-882N (all manufactured by Mitsui Chemicals, Inc.).

Furthermore, examples of the above-mentioned polymers of N-alkoxymethyl acrylamide include N-hydroxymethyl (meth)acrylamide, N-methoxymethyl (meth)acrylamide, N-ethoxymethyl (meth)acrylamide, and N-butoxymethyl (meth)acrylamide. ) Polymers produced using acrylamide or methacrylamide compounds substituted with hydroxymethyl groups or alkoxymethyl groups, such as acrylamide.

Specific examples of such polymers include, for example, poly(N-butoxymethylacrylamide), a copolymer of N-butoxymethylacrylamide and styrene, a copolymer of N-hydroxymethylmethacrylamide and methyl methacrylate, and N-butoxymethylacrylamide. Examples include a copolymer of -ethoxymethylmethacrylamide and benzyl methacrylate, and a copolymer of N-butoxymethylacrylamide, benzyl methacrylate and 2-hydroxypropyl methacrylate. The weight average molecular weight of such a polymer is 1,000 to 200,000, more preferably 3,000 to 150,000, still more preferably 3,000 to 50,000.

Examples of polymers of compounds having epoxy groups include polymers produced using compounds having epoxy groups such as glycidyl methacrylate, 3,4-epoxycyclohexylmethyl methacrylate, and 3,4-epoxycyclohexylmethyl methacrylate. It will be done.

Specific examples of such polymers include poly(3,4-epoxycyclohexylmethyl methacrylate), poly(glycidyl methacrylate), copolymers of glycidyl methacrylate and methyl methacrylate, and 3,4-epoxycyclohexylmethyl methacrylate. Examples include copolymers with methyl methacrylate and copolymers with glycidyl methacrylate and styrene. The weight average molecular weight of such a polymer is 1,000 to 200,000, more preferably 3,000 to 150,000, still more preferably 3,000 to 50,000.

Examples of polymers of the above-mentioned compounds having isocyanate groups include 2-isocyanatoethyl methacrylate (Karens MOI [registered trademark], manufactured by Showa Denko KK), 2-isocyanatoethyl acrylate (Karens AOI [registered trademark]) , manufactured by Showa Denko K.K.), or 2-(0-[1'-methylpropylideneamino]carboxyamino)ethyl methacrylate (Karens MOI-BM [registered trademark], Showa Denko K.K.) ), 2-[(3,5-dimethylpyrazolyl)carbonylamino]ethyl methacrylate (Karenz MOI-BP [registered trademark], manufactured by Showa Denko K.K.) and other compounds having blocked isocyanate groups. Examples include polymers that can be used.

Specific examples of such polymers include, for example, poly(2-isocyanatoethyl acrylate), poly(2-(0-[1'-methylpropylideneamino]carboxyamino)ethyl methacrylate), 2-isocyanatoethyl Examples include a copolymer of methacrylate and styrene, a copolymer of 2-[(3,5-dimethylpyrazolyl)carbonylamino]ethyl methacrylate and methyl methacrylate, and the like. The weight average molecular weight of such a polymer is 1,000 to 200,000, more preferably 3,000 to 150,000, still more preferably 3,000 to 50,000.

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

When the liquid crystal aligning agent used in the present invention contains the crosslinking agent (B), the content is preferably 1 part by mass to 100 parts by mass based on 100 parts by mass of the resin (A). , more preferably 1 part by mass to 80 parts by mass.

[Preparation of liquid crystal alignment agent]
The liquid crystal alignment agent used in the present invention is preferably prepared as a coating liquid so that it is suitable for forming a liquid crystal alignment film. That is, the liquid crystal aligning agent of the present invention is preferably prepared as a solution in which a resin component for forming a resin film is dissolved in an organic solvent. Here, the resin component is the specific polymer which is component (A) described above. At that time, the content of the specific polymer is preferably 0.5 to 20% by mass, more preferably 1 to 20% by mass, even more preferably 1 to 15% by mass, particularly preferably 1 to 15% by mass, based on the entire liquid crystal aligning agent. The content is preferably 10% by mass.

<Solvent>
The solvent contained in the liquid crystal aligning agent used in the present invention is not particularly limited as long as it is a solvent that can dissolve component (A) and optionally component (B). The number of solvents contained in the liquid crystal aligning agent may be one, or a mixture of two or more may be used. Furthermore, the solvent does not have to be a solvent that dissolves the component (A) and the component (B), but can be used in combination with a solvent that dissolves the component (A) and the component (B). In this case, if the surface energy of the solvent that does not dissolve component (A) or (B) is lower than that of the solvent that dissolves component (A) or (B), the coating properties of the liquid crystal aligning agent on the substrate will be improved. It is preferable because it can be done.

Specific examples include water, N-alkyl-2-pyrrolidones such as N-methyl-2-pyrrolidone and N-ethyl-2-pyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, and N-methylcaprolactam. , tetramethylurea, 3-methoxy-N,N-dimethylpropanamide, 3-ethoxy-N,N-dimethylpropanamide, 3-butoxy-N,N-dimethylpropanamide, 1,3-dimethyl-2-imidazo Dialkyl imidazolidinones such as lysinone, lactones such as γ-butyrolactone, γ-valerolactone, and δ-valerolactone, carbonates such as ethylene carbonate and propylene carbonate, methanol, ethanol, propanol, isopropanol, 3-methyl- Ketones such as 3-methoxybutanol, ethyl amyl ketone, methyl nonyl ketone, methyl ethyl ketone, isoamyl methyl ketone, methyl isopropyl ketone, diisobutyl ketone, cyclohexanone, cyclopentanone, methyl isobutyl ketone, 4-hydroxy-4-methyl-2-pentanone compounds represented by the following formula (Sv-1) and compounds represented by the following formula (Sv-2), 4-methyl-2-pentyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, cyclohexyl acetate, Examples include 2-methylcyclohexyl acetate, butyl butyrate, isoamyl butyrate, diisobutyl carbinol, diisopentyl ether, and the like.

In formulas (Sv-1) to (Sv-2), Y ₁ and Y ₂ are each independently a hydrogen atom or a monovalent hydrocarbon group having 1 to 6 carbon atoms, and X ₁ is an oxygen atom or -COO- , X2 is a single bond or a carbonyl group, and R ₁ is an alkanediyl group having 2 to 4 carbon atoms. n ₁ is an integer from 1 to 3. When n ₁ is 2 or 3, a plurality of R ₁ may be the same or different. Z ₁ is a divalent hydrocarbon group having 1 to 6 carbon atoms, and Y ₃ and Y ₄ are each independently a hydrogen atom or a monovalent hydrocarbon group having 1 to 6 carbon atoms.

In formula (Sv-1), the monovalent hydrocarbon group having 1 to 6 carbon atoms in Y ₁ and Y ₂ may be, for example, a monovalent chain hydrocarbon group having 1 to 6 carbon atoms, or a monovalent hydrocarbon group having 1 to 6 carbon atoms. Examples include a monovalent alicyclic hydrocarbon group and a monovalent aromatic hydrocarbon group having 1 to 6 carbon atoms. Examples of the monovalent chain hydrocarbon group having 1 to 6 carbon atoms include an alkyl group having 1 to 6 carbon atoms. The alkanediyl group for R ₁ may be linear or branched.

In formula (Sv-2), examples of the divalent hydrocarbon group having 1 to 6 carbon atoms in Z ₁ include alkanediyl groups having 1 to 6 carbon atoms.
The monovalent hydrocarbon group having 1 to 6 carbon atoms for Y ₃ and Y ₄ includes a monovalent chain hydrocarbon group having 1 to 6 carbon atoms, and a monovalent alicyclic hydrocarbon group having 1 to 6 carbon atoms. and a monovalent aromatic hydrocarbon group having 1 to 6 carbon atoms. Examples of the monovalent chain hydrocarbon group having 1 to 6 carbon atoms include an alkyl group having 1 to 6 carbon atoms.

Specific examples of the solvent represented by formula (Sv-1) include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol-n-propyl ether, ethylene glycol-i-propyl ether, ethylene glycol monobutyl ether ( butyl cellosolve), ethylene glycol monohexyl ether, ethylene glycol dimethyl ether, ethylene glycol monoacetate, ethylene glycol diacetate, ethylene glycol ethyl ether acetate, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl Ether acetate, diethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monoethyl ether acetate, propylene glycol monobutyl ether, dipropylene glycol dimethyl ether, dipropylene glycol monomethyl ether, propylene glycol diacetate, ethylene Glycol, 1,4-butanediol, 3-methoxybutyl acetate, 3-ethoxybutyl acetate, etc.;

Specific examples of the solvent represented by (Sv-2) include methyl glycolate, ethyl glycolate, butyl glycolate, ethyl lactate, butyl lactate, isoamyl lactate, ethyl-3-ethoxypropionate, methyl-3 -methoxypropionate, ethyl 3-methoxypropionate, 3-ethoxypropionic acid, 3-methoxypropionic acid, propyl 3-methoxypropionate, butyl 3-methoxypropionate, and the like.

The solvent preferably has a boiling point of 80 to 200°C. More preferably, the temperature is 80°C to 180°C, and preferred solvents include N,N-dimethylformamide, tetramethylurea, 3-methoxy-N,N-dimethylpropanamide, propanol, isopropanol, and 3-methyl-3-methoxy. Butanol, ethyl amyl ketone, methyl ethyl ketone, isoamyl methyl ketone, methyl isopropyl ketone, diisobutyl ketone, cyclohexanone, cyclopentanone, methyl isobutyl ketone, 4-hydroxy-4-methyl-2-pentanone, 4-methyl-2-pentyl acetate, 2-ethylbutyl acetate, cyclohexyl acetate, 2-methylcyclohexyl acetate, butyl butyrate, isoamyl butyrate, diisobutyl carbinol, diisopentyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol-n-propyl ether, ethylene glycol -i-Propyl ether, ethylene glycol monobutyl ether (butyl cellosolve), ethylene glycol dimethyl ether, ethylene glycol monoacetate, ethylene glycol ethyl ether acetate, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene Glycol monoethyl ether acetate, propylene glycol monobutyl ether, dipropylene glycol dimethyl ether, dipropylene glycol monomethyl ether, 3-methoxybutyl acetate, methyl glycolate, ethyl glycolate, butyl glycolate, ethyl lactate, butyl lactate, isoamyl lactate, Examples include ethyl-3-ethoxypropionate, methyl-3-methoxypropionate, ethyl 3-methoxypropionate, and the like.
It is preferable that the boiling point is in this range, especially when the liquid crystal aligning agent containing the solvent is coated on a plastic substrate to be described later.

<Other ingredients>
The liquid crystal aligning agent used in the present invention may contain components other than the above-mentioned (A) component and (B) component. Examples of such other components include a crosslinking catalyst, a compound that improves film thickness uniformity and surface smoothness when the liquid crystal alignment agent is applied, a compound that improves the adhesion between the liquid crystal alignment film and the substrate, etc. Examples include, but are not limited to.

<Crosslinking catalyst>
A crosslinking catalyst may be added to the liquid crystal aligning agent used in the present invention for the purpose of promoting the reaction between the thermally crosslinkable group A and the thermally crosslinkable group B. Such crosslinking catalysts include p-toluenesulfonic acid, camphorsulfonic acid, trifluoromethanesulfonic acid, p-phenolsulfonic acid, 2-naphthalenesulfonic acid, mesitylenesulfonic acid, p-xylene-2-sulfonic acid, m- Xylene-2-sulfonic acid, 4-ethylbenzenesulfonic acid, 1H,1H,2H,2H-perfluorooctanesulfonic acid, perfluoro(2-ethoxyethane)sulfonic acid, pentafluoroethanesulfonic acid, nonafluorobutane-1- Examples include sulfonic acids such as sulfonic acid and dodecylbenzenesulfonic acid, or hydrates and salts thereof. Examples of compounds that generate acid when heated include bis(tosyloxy)ethane, bis(tosyloxy)propane, bis(tosyloxy)butane, p-nitrobenzyl tosylate, o-nitrobenzyl tosylate, 1,2,3- Phenylene tris(methylsulfonate), p-toluenesulfonic acid pyridinium salt, p-toluenesulfonic acid morphonium salt, p-toluenesulfonic acid ethyl ester, p-toluenesulfonic acid propyl ester, p-toluenesulfonic acid butyl ester, p- Toluenesulfonic acid isobutyl ester, p-toluenesulfonic acid methyl ester, p-toluenesulfonic acid phenethyl ester, cyanomethyl p-toluenesulfonate, 2,2,2-trifluoroethyl p-toluenesulfonate, 2-hydroxybutyl p-toluenesulfonate , N-ethyl-p-toluenesulfonamide and the like.

[Compound that improves film thickness uniformity and surface smoothness]
Examples of compounds that improve the uniformity of film thickness and surface smoothness include fluorosurfactants, silicone surfactants, and nonionic surfactants.
Specifically, for example, FTOP (registered trademark) 301, EF303, EF352 (manufactured by Tochem Products), Megafac (registered trademark) F171, F173, R-30 (manufactured by DIC), Florado FC430, FC431 ( (manufactured by Sumitomo 3M), Asahi Guard (registered trademark) AG710 (manufactured by Asahi Glass Co., Ltd.), Surflon (registered trademark) S-382, SC101, SC102, SC103, SC104, SC105, SC106 (manufactured by AGC Seimi Chemical), etc. .
The proportion of these surfactants used is preferably 0.01 parts by mass to 2 parts by mass, more preferably 0.01 parts by mass to 1 part by mass, based on 100 parts by mass of the resin component contained in the polymer composition. Part by mass.

[Compound that improves adhesion between liquid crystal alignment film and substrate]
Specific examples of compounds that improve the adhesion between the liquid crystal alignment film and the substrate include the following functional silane-containing compounds.
For example, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 2-aminopropyltrimethoxysilane, 2-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane , N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, 3-ureidopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, N-ethoxycarbonyl-3-aminopropyltrimethoxysilane, N-ethoxy Carbonyl-3-aminopropyltriethoxysilane, N-triethoxysilylpropyltriethylenetriamine, N-trimethoxysilylpropyltriethylenetriamine, 10-trimethoxysilyl-1,4,7-triazadecane, 10-triethoxysilyl- 1,4,7-triazadecane, 9-trimethoxysilyl-3,6-diazanonyl acetate, 9-triethoxysilyl-3,6-diazanonyl acetate, N-benzyl-3-aminopropyltrimethoxysilane, N-benzyl-3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltriethoxysilane, N-bis(oxyethylene)-3-aminopropyltrimethoxy Examples include amino-based silane-containing compounds such as silane and N-bis(oxyethylene)-3-aminopropyltriethoxysilane.
When using a compound that improves adhesion to the substrate, the amount used is preferably 0.1 parts by mass to 30 parts by mass based on 100 parts by mass of the resin component contained in the polymer composition. More preferably, it is 1 part by mass to 20 parts by mass.

In some embodiments, a photosensitizer can also be used as an additive to improve the photoreactivity of the photoalignable group. Specific examples include aromatic 2-hydroxyketone (benzophenone), coumarin, ketocoumarin, carbonylbiscoumarin, acetophenone, anthraquinone, xanthone, thioxanthone, and acetophenone ketal.

In the liquid crystal aligning agent used in the present invention, all of the above-mentioned resin components may be the above-mentioned specific polymers, but other polymers other than these (hereinafter also referred to as "other polymers") may be used. They may be mixed. At that time, the content of other polymers in the resin component may be 5 to 95 parts by mass, or 10 to 90 parts by mass, based on a total of 100 parts by mass of component (A) and other polymers. .
Examples of such other polymers include poly(meth)acrylate, polyamic acid, polyamic acid ester, and polyimide, which do not satisfy at least one of the constituent requirements of the above-mentioned specific polymer. Can be mentioned.

The other polymer is preferably a polyimide or a precursor thereof (hereinafter also referred to as a polyimide component), which has a surface energy close to that of the polymer that is component (A). Acrylic components such as component (A) basically have low polarity and low surface energy. On the other hand, polyimide components have high polarity and high surface energy. However, if the difference in surface energy between these two components is too large, they will not mix well and agglomeration will occur, resulting in an uneven film, repelling, and unevenness, which will narrow the process margin. Problems such as this may occur. Therefore, by lowering the polarity of the polyimide component, the surface energy can be controlled to a value that is higher than that of the acrylic component but has a small difference. Methods for lowering the polarity of the polyimide component include a method of chemically imidizing it and then mixing it with component (A), and a method of introducing a side chain.

Such polymers include polymers obtained by chemically imidizing a tetracarboxylic acid derivative such as a known tetracarboxylic dianhydride and a known diamine, and a diamine having a side chain. Examples thereof include the resulting polyimide precursor, a polyimide obtained by imidizing the same, a polyimide precursor obtained using a diamine having a tert-butoxycarbonyloxy group, and a polyimide obtained by imidizing the same. Due to such side chains and chemical imidization, the surface energy can be brought close to that of the acrylic polymer, which is component (A), so when a liquid crystal aligning agent is applied and baked to form a cured film, agglomeration etc. This does not occur and a flat cured film can be provided. Examples of diamines having side chains include diamines represented by formulas (2), (3), (4), and (5) described in paragraphs [0023] to [0039] of International Patent Application Publication WO2016/125870; Specific examples include diamines represented by formulas [A-1] to [A-32]. Examples of diamines having a tertiary-butoxycarbonyloxy group include formulas [A-1], [A-2], and [A-3] described in paragraphs [0011] to [0034] of International Patent Application Publication WO2017/119461. Diamines having this structure and specific examples thereof include the diamines exemplified.

<Liquid crystal alignment film and liquid crystal display element>
The liquid crystal aligning agent of the present invention can be applied to a substrate, baked, and then subjected to alignment treatment such as rubbing or light irradiation, or in some vertical alignment applications, can be made into a liquid crystal alignment film without alignment treatment. can. Examples of substrates include glasses such as float glass and soda glass; polyethylene terephthalate, polybutylene terephthalate, polypropylene, polystyrene, polyether sulfone, polycarbonate, poly(alicyclic olefin), polyvinyl chloride, polyvinylidene chloride, and polyether ether. Transparent substrates made of plastics such as ketone (PEEK) resin films, polysulfone (PSF), polyethersulfone (PES), polyamide, polyimide, acrylic, and triacetyl cellulose can be used.
The transparent conductive film provided on one surface of the substrate includes a NESA film (registered trademark of PPG, Inc., USA) made of tin oxide (SnO ₂ ), an ITO film made of indium oxide-tin oxide (In ₂ O ₃ -SnO ₂ ), etc. Can be used.

<Coating film formation process>
The method for applying the liquid crystal aligning agent of the present invention is not particularly limited, but includes screen printing, flexo printing, offset printing, inkjet, dip coating, roll coating, slit coating, spin coating, etc., and these may be used depending on the purpose. good. After coating onto a substrate using these methods, the solvent can be evaporated using heating means such as a hot plate to form a coating film.

The baking after applying the liquid crystal aligning agent can be carried out at any temperature from 40 to 300°C, preferably from 40 to 250°C, more preferably from 40 to 230°C. When a transparent substrate made of a plastic substrate is used, the temperature is preferably 40 to 150°C, more preferably 80 to 140°C. The firing time is preferably 0.1 to 15 minutes, more preferably 1 to 10 minutes.
The thickness of the coating film formed on the substrate is preferably 5 to 1,000 nm, more preferably 10 to 500 nm or 10 to 300 nm. This firing can be performed using a hot plate, hot air circulation furnace, infrared furnace, etc.

<Light irradiation process>
The light irradiation step in the present invention includes a first irradiation step in which the cured film obtained in the coating film forming step is irradiated with ultraviolet rays from an oblique direction, and a first irradiation step in which the cured film obtained in the coating film forming step is irradiated with ultraviolet rays in an oblique direction. A second irradiation step of irradiating ultraviolet rays from a direction different from that in this order is included, and at least one of the first irradiation step and the second irradiation step includes a light-shielded region and an unshielded region. It is done through a mask.

Examples of the light irradiated in the alignment treatment by light irradiation include ultraviolet rays containing light with a wavelength of 150 to 800 nm, visible light, and the like. Among these, ultraviolet light containing light with a wavelength of 300 to 400 nm is preferred. The irradiation light may be polarized or non-polarized. As the polarized light, it is preferable to use light containing linearly polarized light.

The amount of light irradiation is preferably 0.1 mJ/cm ² or more and less than 1,000 mJ/cm ² , more preferably 1 to 500 mJ/cm ² , and even more preferably 2 to 200 mJ/cm ² . preferable.

The direction of ultraviolet ray irradiation is usually 1° to 89° with respect to the normal to the substrate, preferably 20° to 70°, particularly preferably 30° to 60°. If this angle is too small, there is a problem that the pretilt angle becomes small, and if this angle is too large, there is a problem that it becomes difficult to design the irradiation device.

Methods for adjusting the irradiation direction to the above angle include a method of tilting the substrate itself and a method of tilting the light source, but tilting the light source itself is more preferable from the viewpoint of throughput.

In addition, by using a specific composition of the present invention, a pretilt angle formed by irradiation of ultraviolet rays from one direction can be canceled by irradiation of ultraviolet rays from another direction, and a different pretilt angle can be formed. .
With this, for example, after forming a pretilt angle in a specific direction by exposing the entire surface to ultraviolet rays, by irradiating ultraviolet rays from another direction through a mask, it is possible to easily form multiple regions with different orientation directions (orientation division). This makes it possible to efficiently manufacture a multi-domain liquid crystal display element.

The multi-domain liquid crystal alignment film obtained by the manufacturing method of the present invention has a region 1 in which the pretilt angle is tilted by -0.1° to -10° from 90° as a pretilt angle suitable for vertical alignment mode, and region 1 where the pretilt angle is tilted from 90° to +10°. It is preferable to have the region 2 inclined by 0.1° to plus 10°. That is, it is preferable to have a region 1 of 80° to 89.9° and a region 2 of 90.1° to 100° as a pretilt angle, and a region 1 of 85° to 89° and a region 2 of 91° to 95°. It is further preferable to have.

Note that when forming the above regions 1 and 2, region 1 may be formed in the first irradiation step, and region 2 may be formed in the second irradiation step, or region 2 may be formed in the first irradiation step. However, region 1 may be formed in the second irradiation step. When the first irradiation step is performed without using a mask, the amount of light irradiated in the second irradiation step is preferably greater than the amount of light irradiated in the first irradiation step. On the other hand, when the first irradiation step is performed through a mask, the amount of light irradiated in the second irradiation step is preferably smaller than the amount of light irradiated in the first irradiation step.

According to the present invention, when a patterned mask is used in both the first irradiation process and the second irradiation process, even if the mask is shifted, the second irradiation area is the same as the first irradiation area. Since the tilt can be canceled and rewritten to the tilt angle from the second irradiation, "dark lines" will not occur if the mask is misaligned.

The liquid crystal display element of the present invention can be produced by a conventional method using the multi-domain liquid crystal alignment film obtained in the present invention, and the production method is not particularly limited. It is preferable that the pair of substrates face each other with an appropriate gap therebetween, and that a spacer is disposed between the substrates in order to make the thickness of the liquid crystal sandwiched between the substrates uniform. As this spacer, known spacer materials such as a conventional scattering type spacer and a spacer formed from a photosensitive spacer forming composition can be used, as well as unevenness formed on a layer made of a cured liquid crystal material. It is also possible to use it as a spacer.

<Liquid crystal clamping process>
For constructing a liquid crystal cell by sandwiching a liquid crystal between substrates, there are, for example, the following two methods. The first method is to place a pair of substrates facing each other with a gap (cell gap) in between so that the respective liquid crystal alignment films face each other, and then bond the peripheral parts of the pair of substrates together using a sealant. A method for producing a liquid crystal cell can be mentioned by injecting liquid crystal into a cell gap defined by a suitable sealant and then sealing the injection hole.

As a second method, for example, an ultraviolet light-curable sealing material is applied to a predetermined location on one of the two substrates on which a liquid crystal alignment film is formed, and then a sealing material that is cured by ultraviolet light is applied to several predetermined locations on the surface of the liquid crystal alignment film. After dropping the liquid crystal onto the substrate, the other substrate is attached so that the liquid crystal alignment films face each other, the liquid crystal is spread over the entire surface of the substrate, and then the entire surface of the substrate is irradiated with ultraviolet light to harden the sealant. A method for manufacturing cells (ODF (One Drop Fill) method) can be mentioned.

Examples of liquid crystals include fluorine-based liquid crystals and cyano-based liquid crystals that have positive or negative dielectric anisotropy depending on the application, and liquid crystal compounds or liquid crystal compositions that are polymerized by at least one of heating and light irradiation. (hereinafter also referred to as a polymerizable liquid crystal or a curable liquid crystal composition) may be used.
In an embodiment, the step of forming the coating film of the liquid crystal aligning agent may be performed by a roll-to-roll method. If the roll-to-roll method is used, it becomes possible to simplify the manufacturing process of the liquid crystal display element and thereby reduce the manufacturing cost.
A liquid crystal display element can be obtained by attaching polarizing plates to both outer surfaces of the liquid crystal cell.

The polarizing plate used on the outside of the liquid crystal cell is either a polarizing plate in which a polarizing film called "H film", which is made by stretching and aligning polyvinyl alcohol and absorbing iodine, is sandwiched between cellulose acetate protective films, or the H film itself. Examples include polarizing plates.
The liquid crystal alignment film obtained from the liquid crystal aligning agent of the present invention as described above has good liquid crystal alignment, excellent pretilt angle expression ability, and high reliability. Furthermore, the liquid crystal display element manufactured by the method of the present invention has excellent display characteristics.

The structures of the compounds used in the examples are shown below.
In addition, in the formula, "t" indicates that the cyclohexyl group is trans type.

MA-1, MA-2, MA-3, and MA-4 are photoalignable monomers, and CR-1, CR-2, MOI-BP, HEMA, and MAA are thermally crosslinkable monomers.

X-1, X-2, and X-3 are tetracarboxylic dianhydride monomers.

X-4 is a side chain diamine monomer, and X-5 and X-6 are other diamine monomers.

The abbreviations of organic solvents used in Examples are as follows.
PGME: Propylene glycol monomethyl ether CHN: Cyclohexanone The abbreviations of the polymerization initiators used in Examples are as follows.
AIBN: 2,2'-azobisisobutyronitrile

<Polymer molecular weight measurement>
The molecular weight of the polymer in the synthesis example was measured as follows using a normal temperature gel permeation chromatography (GPC) device (SSC-7200 manufactured by Senshu Kagaku Co., Ltd. and columns (KD-803, KD-805) manufactured by Shodex Co., Ltd.).
Column temperature: 50℃
Eluent: DMF (as additives, lithium bromide-hydrate (LiBr.H ₂ O) is 30 mmol/L, phosphoric acid/anhydrous crystal (o-phosphoric acid) is 30 mmol/L, THF is 10 ml/L)
Flow rate: 1.0 ml/min Standard samples for creating a calibration curve: TSK standard polyethylene oxide manufactured by Tosoh Corporation (molecular weight approx. 9000,000, 150,000, 100,000, 30,000) and polyethylene glycol manufactured by Polymer Laboratory Co., Ltd. molecular weight approximately 12,000, 4,000, 1,000).

<Reference example 1>
MA-1 (4.95 g, 12.0 mmol) and MOI-BP (7.04 g, 28.0 mmol) were dissolved in CHN (69.8 g), and after degassing with a diaphragm pump, AIBN (0 .33 g, 2.0 mmol) was added and degassed again. Thereafter, the mixture was reacted at 55° C. for 13 hours to obtain a methacrylate polymer solution. This polymer solution was added dropwise to a mixed solvent (1000 ml) of methanol and pure water = 5/5, and the resulting precipitate was filtered. This precipitate was washed with methanol and dried under reduced pressure in an oven at 40°C to obtain a methacrylate polymer powder (A). This polymer had a number average molecular weight of 44,200 and a weight average molecular weight of 141,800.
CHN (18.0 g) was added to the obtained methacrylate polymer powder (A) (1.5 g) and dissolved by stirring at room temperature for 5 hours. CR-1 (0.15 g) and PGME (18.0 g) were added to this solution and stirred to obtain a liquid crystal aligning agent (A1).

<Example 1-0>
[Preparation of liquid crystal cell]
The liquid crystal alignment agent (A1) obtained in Reference Example 1 was spin-coated on the ITO surface of a glass substrate with a transparent electrode made of an ITO film, and dried on a 40° C. hot plate for 300 seconds. Next, baking was performed on a hot plate at 120° C. for 10 minutes to form a liquid crystal alignment film with a thickness of 100 nm. Thereafter, 50 mJ/cm ² of linearly polarized ultraviolet light of 313 nm with an irradiation intensity of 4.3 mW/cm ² is irradiated onto the coating surface of the alignment film from an angle inclined by 40 degrees from the normal direction of the substrate. A substrate with a liquid crystal alignment film was obtained. The linearly polarized ultraviolet light of 313 nm to be irradiated was extracted by passing ultraviolet light emitted from a high-pressure mercury lamp through a 313 nm band-pass filter and a Brewster polarizing plate.
Two of the above substrates were prepared, and after 4 μm bead spacers were sprinkled on the liquid crystal alignment film of one substrate, a sealant (XN-1500T, manufactured by Mitsui Chemicals) was applied. Next, the other substrate is pasted together so that the liquid crystal alignment film surfaces face each other and the irradiation direction of the incident polarized ultraviolet light is 180° with respect to the irradiation direction of the ultraviolet light incident on the opposing substrate, Empty cells were prepared by thermally curing the sealant at 120° C. for 90 minutes. A negative liquid crystal (MLC-3022, manufactured by Merck & Co., Ltd.) was injected into this empty cell by a reduced pressure injection method to produce a liquid crystal cell.

[Evaluation of pretilt angle]
The pretilt angle of the liquid crystal cell was measured by the Mueller matrix method using "AxoScan" manufactured by Axo Metrix. The results are summarized in Table 1.

[Evaluation of liquid crystal orientation]
After fabricating the liquid crystal cell, perform isotropic phase treatment at 120°C for 1 hour, then observe the cell using a polarizing microscope. A case where the liquid crystal could be driven was considered to have good alignment. The results are summarized in Table 1.

<Example 1-1>
In Example 1-0 [Preparation of liquid crystal cell], after irradiating linearly polarized ultraviolet rays at 50 mJ/ ^cm2 from an angle inclined at 40 degrees from the normal direction of the substrate, 50 mJ was further applied from an angle inclined at 40 degrees from the normal direction of the substrate. A liquid crystal cell was obtained in the same manner as in Example 1-0 except that / ^cm2 irradiation was performed. Note that the first irradiation and the second irradiation were performed at an angle of 40 degrees in opposite directions from the normal direction. Furthermore, the pretilt angle and liquid crystal cell orientation were evaluated in the same manner as in Example 1-0.

<Example 1-2, 1-3>
In Example 1-1 [Preparation of liquid crystal cell], except that the second polarized ultraviolet irradiation amount was changed to 100 mJ/cm ² (Example 1-2) and 150 mJ/cm ² (Example 1-3). A liquid crystal cell was obtained in the same manner as in Example 1-1. Furthermore, the pretilt angle and liquid crystal cell orientation were evaluated in the same manner as in Example 1-0.

<Reference example 2>
MA-1 (4.95 g, 12.0 mmol), MOI-BP (3.52 g, 14.0 mmol), and HEMA (1.82 g, 14.0 mmol) were dissolved in CHN (60.2 g), and a diaphragm pump was added. After deaeration, AIBN (0.33 g, 2.0 mmol) was added and deaeration was performed again. Thereafter, the mixture was reacted at 55° C. for 13 hours to obtain a methacrylate polymer solution. This polymer solution was added dropwise to a mixed solvent (1000 ml) of methanol and pure water = 5/5, and the resulting precipitate was filtered. This precipitate was washed with methanol and dried under reduced pressure in an oven at 40°C to obtain a methacrylate polymer powder (B). This polymer had a number average molecular weight of 33,800 and a weight average molecular weight of 123,500.
CHN (18.0 g) was added to the obtained methacrylate polymer powder (B) (1.5 g) and dissolved by stirring at room temperature for 5 hours. PGME (18.0 g) was added to this solution and stirred to obtain a liquid crystal aligning agent (B1).

<Reference example 3>
MA-1 (3.30 g, 8.0 mmol) and MAA (2.75 g, 32.0 mmol) were dissolved in CHN (36.2 g), and after degassing with a diaphragm pump, AIBN (0.33 g , 2.0 mmol) was added and degassed again. Thereafter, the mixture was reacted at 55° C. for 13 hours to obtain a methacrylate polymer solution. This polymer solution was added dropwise to a mixed solvent (1000 ml) of methanol and pure water = 5/5, and the resulting precipitate was filtered. This precipitate was washed with methanol and dried under reduced pressure in an oven at 40°C to obtain a methacrylate polymer powder (C). This polymer had a number average molecular weight of 51,500 and a weight average molecular weight of 143,000.
CHN (18.0 g) was added to the obtained methacrylate polymer powder (C) (1.5 g) and dissolved by stirring at room temperature for 5 hours. CR-2 (0.45 g) and PGME (18.0 g) were added to this solution and stirred to obtain a liquid crystal aligning agent (C1).

<Reference example 4>
X-4 (2.28g, 3.00mmol), X-5 (1.22g, 4.00mmol), X-6 (1.45g, 3.00mmol) and X-1 (2.23g, 6.00mmol) ) was dissolved in NMP (27.2 g) and reacted at 60°C for 5 hours, then X-2 (1.00 g, 2.00 mmol) and X-3 (0.87 g, 2.00 mmol) and NMP (9.1 g) was added and reacted at 40° C. for 10 hours to obtain a polyamic acid polymer solution.
After adding NMP to the polyamic acid polymer solution (50 g) and diluting it to 6.5% by mass, acetic anhydride (8.8 g) and pyridine (2.7 g) were added as imidization catalysts, and the mixture was reacted at 75°C for 2.5 hours. I let it happen. This reaction solution was poured into methanol (700 ml), and the resulting precipitate was filtered off. This precipitate was washed with methanol and dried under reduced pressure at 100°C to obtain a polyimide polymer powder. The imidization rate of this polyimide polymer was 71%, the number average molecular weight was 13,000, and the weight average molecular weight was 42,000.
NMP (44.0 g) was added to the obtained polyimide powder (6.0 g) and dissolved by stirring at 70° C. for 20 hours. NMP (10.0 g) and BCS (40.0 g) were added to this solution, and the mixture was stirred at room temperature for 5 hours to obtain a polyimide polymer solution (H1).
The obtained polyimide polymer solution (H1) (14.0 g) and the liquid crystal aligning agent (B1) (6.0 g) obtained in Reference Example 2 were stirred at room temperature for 5 hours to prepare the liquid crystal aligning agent (D1). Obtained.

<Reference example 5>
The polyimide polymer solution (H1) (14.0 g) obtained in Reference Example (4) and the liquid crystal alignment agent (C1) (6.0 g) obtained in Reference Example 3 were stirred at room temperature for 5 hours to form a liquid crystal. An alignment agent (E1) was obtained.

<Examples 2-0 to 5-3>
Tests were conducted in the same manner as in Examples 1-0 to 1-3, except that the liquid crystal aligning agent listed in Table 1 was used instead of the liquid crystal aligning agent (A1) obtained in Reference Example 1. The evaluation results are shown in Table 1.

<Reference example 6>
MA-2 (13.74 g, 24.0 mmol) and MA-3 (7.02 g, 16.0 mmol) were dissolved in CHN (119.5 g), and after degassing with a diaphragm pump, AIBN (0 .33 g, 2.0 mmol) was added and degassed again. Thereafter, the mixture was reacted at 55° C. for 13 hours to obtain a methacrylate polymer solution. This polymer solution was added dropwise to a mixed solvent (1000 ml) of methanol and pure water = 5/5, and the resulting precipitate was filtered. This precipitate was washed with methanol and dried under reduced pressure in an oven at 40°C to obtain a methacrylate polymer powder (D). This polymer had a number average molecular weight of 35,700 and a weight average molecular weight of 126,000.
CHN (18.0 g) was added to the obtained methacrylate polymer powder (D) (1.5 g) and dissolved by stirring at room temperature for 5 hours. A liquid crystal aligning agent (F1) was obtained by adding CHN (18.0 g) to this solution and stirring.

<Comparative example 1-0>
[Preparation of liquid crystal cell]
The liquid crystal alignment agent (F1) obtained in Reference Example 6 was spin-coated on the ITO surface of a glass substrate with a transparent electrode made of an ITO film, and dried on a hot plate at 40°C for 300 seconds to form a liquid crystal alignment agent with a film thickness of 100 nm. A film was formed. The coating surface was irradiated with 50 mJ/cm ² of linearly polarized ultraviolet rays of 313 nm and an irradiation intensity of 4.3 mW/cm ² from an angle inclined at 40° from the normal direction of the substrate through a polarizing plate. Next, baking was performed on a hot plate at 120° C. for 10 minutes to obtain a substrate with a liquid crystal alignment film. Incoming linearly polarized UV light was prepared by passing ultraviolet light from a high-pressure mercury lamp through a 313 nm band-pass filter and then passing it through a 313 nm polarizing plate.
Two of the above substrates were prepared, and after 4 μm bead spacers were sprinkled on the liquid crystal alignment film of one substrate, a sealant (manufactured by Kyoritsu Chemical Co., Ltd., XN-1500T) was applied. Next, the other substrate was bonded together so that the liquid crystal alignment film surfaces faced each other and the alignment direction was 180°, and then the sealant was thermally cured at 120° C. for 90 minutes to prepare an empty cell. A negative liquid crystal (MLC-3022, manufactured by Merck & Co., Ltd.) was injected into this empty cell by a reduced pressure injection method to produce a liquid crystal cell.
Furthermore, the pretilt angle and liquid crystal cell orientation were evaluated in the same manner as in Example 1-0.

<Comparative example 1-1>
In [Preparation of liquid crystal cell] of Comparative Example 1-0, after irradiating linearly polarized ultraviolet rays at 50 mJ/ ^cm2 from an angle inclined at 40 degrees from the normal direction of the substrate, 50 mJ was further applied from an angle inclined at 40 degrees from the normal direction of the substrate. A liquid crystal cell was obtained in the same manner as in Comparative Example 1-0, except that /cm ² irradiation was performed. Note that the first irradiation and the second irradiation were performed at an angle of 40 degrees in opposite directions from the normal direction. Furthermore, the pretilt angle and liquid crystal cell orientation were evaluated in the same manner as in Example 1-0.

<Comparative Examples 1-2, 1-3>
In Comparative Example 1-0 [Preparation of liquid crystal cell], except that the second polarized ultraviolet irradiation amount was changed to 100 mJ/cm ² (Comparative Example 1-2) and 150 mJ/cm ² (Comparative Example 1-3). A liquid crystal cell was obtained in the same manner as in Comparative Example 1. Furthermore, the pretilt angle and liquid crystal cell orientation were evaluated in the same manner as in Example 1-0.

<Reference example 7>
MA-2 (17.18 g, 30.0 mmol) and MAA (1.72 g, 20.0 mmol) were dissolved in NMP (108.51 g), and after degassing with a diaphragm pump, AIBN (0.25 g , 1.5 mmol) and degassing was performed again. Thereafter, the mixture was reacted at 55° C. for 13 hours to obtain a methacrylate polymer solution. This polymer solution was added dropwise to a mixed solvent (1000 ml) of methanol and pure water = 5/5, and the resulting precipitate was filtered. This precipitate was washed with methanol and dried under reduced pressure in an oven at 40°C to obtain a methacrylate polymer powder (E). This polymer had a number average molecular weight of 22,700 and a weight average molecular weight of 131,000.
CHN (18.0 g) was added to the obtained methacrylate polymer powder (E) (1.5 g) and dissolved by stirring at room temperature for 5 hours. A liquid crystal aligning agent (G1) was obtained by adding CHN (18.0 g) to this solution and stirring.

<Comparative Examples 2-0 to 2-3>
Using the liquid crystal aligning agent (G1) obtained in Reference Example 7, tests were conducted in the same manner as in Comparative Examples 1-0 to 1-3, except that the firing temperature was changed from 120°C to 150°C.

<Reference example 8>
MA-4 (4.05 g, 8.0 mmol) and MAA (2.75 g, 32.0 mmol) were dissolved in CHN (28.5 g), and after degassing with a diaphragm pump, AIBN (0.33 g , 2.0 mmol) was added and degassed again. Thereafter, the mixture was reacted at 55° C. for 13 hours to obtain a methacrylate polymer solution. This polymer solution was added dropwise to a mixed solvent (1000 ml) of methanol and pure water = 5/5, and the resulting precipitate was filtered. This precipitate was washed with methanol and dried under reduced pressure in an oven at 40°C to obtain methacrylate polymer powder (H). This polymer had a number average molecular weight of 47,000 and a weight average molecular weight of 140,000.
CHN (18.0 g) was added to the obtained methacrylate polymer powder (H) (1.5 g) and dissolved by stirring at room temperature for 5 hours. CR-2 (0.45 g) and PGME (18.0 g) were added to this solution and stirred to obtain a liquid crystal aligning agent (I1).

<Reference example 9>
Stir the polyimide polymer solution (H1) (14.0 g) obtained in Reference Example (4) and the liquid crystal alignment agent (I1) (6.0 g) obtained in Reference Example (8) at room temperature for 5 hours. A liquid crystal aligning agent (J1) was obtained.

<Examples 6-0 to 7-3>
Tests were conducted in the same manner as in Examples 1-0 to 1-3, except that the liquid crystal aligning agent listed in Table 2 was used instead of the liquid crystal aligning agent (A1) obtained in Reference Example 1. The evaluation results are shown in Table 2.

As is clear from Tables 1 and 2, in all Examples, the tilt angle could be rewritten by performing the second irradiation, and the liquid crystal orientation after rewriting was also good. On the other hand, in all comparative examples, it was impossible to rewrite the tilt angle.

According to the manufacturing method of the present invention, a multi-domain liquid crystal alignment film can be efficiently manufactured. Further, a liquid crystal display device using the obtained multi-domain liquid crystal alignment film can be suitably used as a liquid crystal display device for ECB and the like.

Claims (5)

A method for manufacturing a multi-domain liquid crystal alignment film, the method comprising:
A step of applying a liquid crystal aligning agent onto a substrate and forming a cured film by drying and baking;
a first irradiation step of irradiating the cured film with ultraviolet rays from an oblique direction, and
A second irradiation step of irradiating the cured film obtained by the first irradiation step with ultraviolet rays from a direction different from the irradiation direction in the first irradiation step in this order,
At least one of the first irradiation step and the second irradiation step is performed through a mask including a light-shielded region and an unshielded region,
The liquid crystal aligning agent is (A) the following formula (pa-1)

(In the formula, A is optionally a group selected from fluorine, chlorine, cyano, or an alkoxy group having 1 to 5 carbon atoms, a linear or branched alkyl residue (this can optionally be one pyrimidine-2,5-diyl, pyridine-2,5-diyl, 2,5-thiophenylene, 2,5-diyl, which may be substituted with a cyano group or one or more halogen atoms) -furanylene, 1,4- or 2,6-naphthylene, or phenylene, R ₁ is a single bond, oxygen atom, -COO- or -OCO-, and R ₂ is a divalent aromatic group, a divalent aromatic group, It is an alicyclic group, a divalent heterocyclic group, or a divalent fused cyclic group, R ₃ is a single bond, an oxygen atom, -COO- or -OCO-, and R ₄ has 1 to 40 carbon atoms. is a monovalent organic group having 3 to 40 carbon atoms containing a linear or branched alkyl group or alicyclic group, and D is an oxygen atom, a sulfur atom, or -NR _d - (where R _d is , represents a hydrogen atom or an alkyl having 1 to 3 carbon atoms), a is an integer from 0 to 3, and * represents the bonding position.)
The liquid crystal aligning agent contains a polymer having a photoalignable group and a thermally crosslinkable group A represented by: and a solvent, and
Z1: The (A) polymer further has a thermally crosslinkable group B, and/or Z2: (B) The polymer further contains a compound having two or more thermally crosslinkable groups B in the molecule (thermally crosslinkable Group A and thermally crosslinkable group B each independently include a carboxyl group, an amino group, an alkoxymethylamide group, a hydroxymethylamide group, a hydroxyl group, an epoxy site-containing group, an oxetanyl group, a thiiranyl group, an isocyanate group, and a blocked isocyanate group. A group selected from the group consisting of thermally crosslinkable group A and thermally crosslinkable group B such that they undergo a crosslinking reaction with heat, provided that thermally crosslinkable group A and thermally crosslinkable group B are mutually They may be the same.)
A method characterized by: The method according to claim 1, wherein at least one of the ultraviolet rays irradiated in the first irradiation step and the second irradiation step is polarized ultraviolet rays. 2. The method of claim 1, wherein only the second irradiation step is performed through the mask. A multi-domain liquid crystal alignment film formed using the method according to any one of claims 1 to 3. A liquid crystal display device comprising the multi-domain liquid crystal alignment film according to claim 4.