WO2023136269A1

WO2023136269A1 - Liquid crystal alignment agent, liquid crystal alignment film, and liquid crystal display element

Info

Publication number: WO2023136269A1
Application number: PCT/JP2023/000516
Authority: WO
Inventors: 祐太飯塚
Original assignee: 日産化学株式会社
Priority date: 2022-01-13
Filing date: 2023-01-12
Publication date: 2023-07-20
Also published as: TW202344671A

Abstract

[Problem] The present invention provides a liquid crystal alignment film and a liquid crystal alignment agent, with each of which it is possible to achieve good liquid crystal alignment properties, excellent pre-tilt angle expression capability, and high reliability even when a firing time is shortened. The present invention provides a liquid crystal alignment agent containing a component (A) and a solvent. The component (A) is a polymer that has the following structures (A-1) to (A-4): a structure (A-1) having at least one functional group selected from a carboxy group, an amino group, and a hydroxy group; a structure (A-2) represented by a formula (pa-1); a structure (A-3) having at least one functional group selected from an oxetanyl group, an oxiranyl group, and the like; and a structure (A-4) represented by a formula (pa-2). (The symbols in the formulas are as defined in the description.)

Description

Liquid crystal alignment agent, liquid crystal alignment film, and liquid crystal display element

The present invention relates to a liquid crystal aligning agent, a liquid crystal alignment film obtained thereby, and a liquid crystal display element comprising the obtained liquid crystal alignment film. More specifically, even when the baking temperature is low and the baking time is short, the liquid crystal aligning agent is capable of providing a liquid crystal alignment film having good liquid crystal alignment, excellent pretilt angle expression ability, and high reliability. and to a liquid crystal display element having excellent display quality.

In the liquid crystal display element, the liquid crystal alignment film plays a role of orienting the liquid crystal in a certain direction. Currently, the main liquid crystal alignment films used industrially are polyimide precursors such as polyamic acid (also known as polyamic acid), polyamic acid esters, and polyimide-based liquid crystal alignment agents made of polyimide solutions on substrates. It is produced by applying and forming a film.
Further, in the case of aligning the liquid crystal parallel or obliquely with respect to the substrate surface, surface stretching treatment by rubbing is further performed after the film formation.

On the other hand, when the liquid crystal is aligned perpendicularly to the substrate (called a vertical alignment (VA) system), a long-chain alkyl, a cyclic group, or a combination of a cyclic group and an alkyl group (see, for example, Patent Document 1), a steroid skeleton ( For example, see Patent Document 2), a liquid crystal alignment film in which a hydrophobic group is introduced into a side chain of polyimide is used. In this case, when a voltage is applied between the substrates to tilt the liquid crystal molecules in a direction parallel to the substrates, it is necessary to tilt the liquid crystal molecules from the direction normal to the substrates toward one direction within the plane of the substrates. . As a means for this, for example, a method of providing a projection on the substrate, a method of providing a slit in the display electrode, or a method of slightly tilting the liquid crystal molecules from the normal direction of the substrate toward one direction within the substrate surface by rubbing ( Pretilt) method, further, by adding a photopolymerizable compound in advance to the liquid crystal composition, using it together with a vertical alignment film such as polyimide, and irradiating ultraviolet rays while applying a voltage to the liquid crystal cell, the liquid crystal is pretilt. A method (for example, see Patent Document 3) is proposed.

In recent years, as an alternative to the formation of protrusions and slits in the VA liquid crystal alignment control and the PSA technology, a method using an anisotropic photochemical reaction caused by polarized ultraviolet irradiation or the like (photo alignment method) has also been proposed. That is, it is known that the tilt direction of liquid crystal molecules can be uniformly controlled when a voltage is applied by irradiating a photoreactive, vertically aligned polyimide film with polarized ultraviolet rays to impart alignment control ability and pretilt angle expression. (see Patent Document 4). In this case as well, a polyimide-based liquid crystal alignment film, which is excellent in durability and suitable for controlling the pretilt angle of liquid crystal, is used as in the conventional alignment film.

On the other hand, as a solvent for a liquid crystal aligning agent using a polyimide polymer, a highly polar solvent such as N-methyl-2-pyrrolidone (also referred to as NMP) is used because the solvent solubility of these polyimide polymers is low. It is used. These highly polar solvents have high boiling points. For example, NMP has a boiling point of 200° C. or higher. Therefore, in order to produce a liquid crystal alignment film using a liquid crystal alignment treatment agent using NMP as a solvent, in order to eliminate NMP remaining in the liquid crystal alignment film, at a high temperature of about 200 ° C. which is near the boiling point of NMP firing is required.

On the other hand, if a plastic substrate that is thin and lightweight but has low heat resistance is used for the substrate of the liquid crystal display element, it is necessary to bake at a lower temperature when manufacturing the liquid crystal alignment film. Similarly, it is also required to reduce the energy cost in manufacturing liquid crystal display elements by lowering the firing temperature.

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

JP-A-3-179323 JP-A-4-281427 Japanese Patent No. 4504626 Japanese Patent No. 4995267 JP-A-7-209633

As a result of investigation by the present inventor, it was found that when a liquid crystal alignment film was produced by lowering the baking temperature and shortening the baking time, the liquid crystal orientation was significantly impaired in addition to the above. An object of the present invention is to provide a liquid crystal aligning film and a liquid crystal aligning agent that have good liquid crystal alignment properties, excellent pretilt angle expression ability, and high reliability even if the baking time is shortened. .

The present inventors have discovered an invention having the following <1> as a gist.
<1> A liquid crystal aligning agent containing the following (A) component and a solvent.
Component (A): A polymer having the following structures (A-1) to (A-4).
(A-1) A structure having at least one functional group selected from the group consisting of a carboxy group, an amino group and a hydroxy group (hereinafter also referred to as "polar group").
(A-2) A structure represented by the following formula (pa-1) (hereinafter also referred to as “photo-alignment group 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 (which is optionally one cyano group or substituted with one or more halogen atoms), pyrimidine-2,5-diyl, pyridine-2,5-diyl, thiophene-2,5-diyl, furan-2,5 -diyl, 1,4- or 2,6-naphthylene or phenylene, R ₁ is a single bond, an oxygen atom, -COO- or -OCO-, R ₂ is a divalent aromatic group, a divalent an alicyclic group, a divalent heterocyclic group or a divalent condensed 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 including a linear or branched alkyl group or alicyclic group, and D is an oxygen atom, a sulfur atom or —NR _d — (wherein R _d is , representing a hydrogen atom or alkyl having 1 to 3 carbon atoms), X and Y each independently represent a hydrogen atom, a fluorine atom, a chlorine atom, a cyano group or an alkyl group having 1 to 3 carbon atoms, a is an integer of 0 to 3, and * represents a bond. When a is 2 or more, each of the plurality of R ₁ and R ₂ independently has the above definition.
(A-3) an oxetanyl group, an oxiranyl group, a group represented by the following formula (3), a group represented by the following formula (4), a group represented by the following formula (5) (in each formula, * represents a bond.) and a structure having at least one functional group selected from the group consisting of a thiirane group (hereinafter also referred to as a “thermally crosslinkable group”).

(A-4) A structure represented by the following formula (pa-2) (hereinafter also referred to as “photo-alignment group 2”).

wherein L ₁ , L ₂ and L ₃ each independently represent a single bond, -O-, -CH ₂ -, -COO-, -OCO-, -CONH- or -NH-CO-;
T is a single bond or an alkylene group having 1 to 12 carbon atoms, and the hydrogen atoms bonded thereto may be replaced with a halogen group;
when T is a single bond then _L2 also represents a single bond;
Y ₁ is a divalent benzene ring;
P ₁ and Q ₁ are each independently a group selected from the group consisting of a benzene ring and an alicyclic hydrocarbon ring having 5 to 8 carbon atoms;
R ₁₁ is a hydrogen atom, —CN, a halogen group, an alkyl group having 1 to 5 carbon atoms, an (alkyl having 1 to 5 carbon atoms)carbonyl group, a cycloalkyl group having 3 to 7 carbon atoms or a cycloalkyl group having 1 to 5 carbon atoms. It is an alkyloxy group.
In Y ₁ , P ₁ and Q ₁ , the hydrogen atoms bonded to the benzene ring are each independently —CN, a halogen group, an alkyl group having 1 to 5 carbon atoms, an (alkyl having 1 to 5 carbon atoms) carbonyl group, or a carbon may be substituted with an alkyloxy group of numbers 1 to 5;
X ₁ represents a single bond, -O-, -COO- or -OCO-;
n1 is 0, 1 or 2;
when the number of X ₁ is 2, X ₁ may be the same or different;
When the number of Q ₁ is 2, Q ₁ may be the same or different;
A dashed line represents a bond with a polymerizable group.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a liquid crystal aligning film and a liquid crystal aligning agent that have good liquid crystal alignment properties, excellent pretilt angle expression ability, and high reliability even if the baking time is shortened.
Also, the liquid crystal display device manufactured by the method of the present invention has excellent display characteristics.

The liquid crystal aligning agent of the present invention contains a polymer having the structures (A-1) to (A-4) (hereinafter also referred to as "specific polymer") and a liquid crystal aligning agent containing a solvent. Here, since all of the above four structures can be side chains in a polymer, they can also be referred to as "side chains" if necessary.
Moreover, * represents a bond throughout this specification.
Hereinafter, each component of the present invention will be described in detail.

<(A) component: specific polymer>
The specific polymer of the present invention is represented by the following formula (I).

During the ceremony,
S _a , S _b , S _c and S _d each represent an independent spacer unit,
I _a1 has the same definition as in formula (a-1-m) described later,
I _b is a group represented by the formula (pa-1),
I _c is selected from the group consisting of an oxetanyl group, an oxiranyl group, a group represented by the formula (3), a group represented by the formula (4), a group represented by the formula (5), and a thiirane group. represents a monovalent organic group having at least one functional group represented by
I _d is a group represented by the above formula (pa-2).
M _a , M _c , M _d , M _e , M _f , M _g , r ₁ , r ₂ , and r ₃ are the formulas (a-1-m), (b-1-m), and ( c-1-m) and the definition given in formula (d-1-m).

Also, w, x, y, and z are not particularly limited as long as they are all greater than 0. For example, w, x, y, and z each independently take a value of 0.01 or more and 0.89 or less. can be done.
The formula (I) means that each side chain exists in the ratio of w, x, y, z, and in the polymer, a block copolymer in which each side chain is blocked does not mean

Because the specific polymer contained in the liquid crystal aligning agent of the present invention has high sensitivity to light, it can exhibit alignment controllability even with low-exposure polarized UV irradiation. Furthermore, the reaction of the thermally crosslinkable group with the amino group and the hydroxy group or the carboxy group allows the specific polymer to undergo a cross-linking reaction within the specific polymer even when the liquid crystal aligning agent is baked for a short period of time. As a result, when the photo-alignment site of the specific polymer exhibits anisotropy due to a photoreaction, the anisotropy tends to remain in the liquid crystal alignment film (memory), so the liquid crystal alignment is improved and the liquid crystal It becomes possible to develop a pretilt angle.

<(A-1) Structure Having a Polar Group>
The specific polymer contained in the liquid crystal aligning agent of the present invention has at least one functional group selected from polar groups, ie, carboxy groups, amino groups and hydroxy groups, in the molecule, preferably in the side chain. have a structure.
This structure can enhance the liquid crystal orientation of the obtained liquid crystal alignment film and express the pretilt angle of the liquid crystal even when the baking time of the liquid crystal alignment agent obtained from the specific polymer of the present invention is shortened. .

In the present invention, a structure having a polar group can be represented, for example, by the following formula (a-1). Further, examples of the structure include, but are not limited to, structures derived from monomers represented by the following formula (a-1-m).

In the formula, _Ia1 is a monovalent group selected from a carboxy group, a hydroxy group, a group having at least one partial structure represented by the following formula (a2), or a primary amino group. However, the following formula (a2) represents a group other than a primary amino group, and r1 is ₁ or 2.

Moreover, S _a represents a single bond or a divalent linking group. When r ₁ is 2, each of the plurality of S _a and I _a1 independently has the above definition.

In _Ia1 , the group having the partial structure of formula (a2) includes, for example, a 5-membered or 6-membered nitrogen-containing heterocyclic ring, such as a piperidine ring and a morpholine ring. Each of these groups may be unsubstituted or one or more hydrogen atoms may be substituted by a fluorine atom, chlorine atom, cyano group, methyl group or methoxy group. Preferred examples of _Ia1 include a monovalent group selected from a carboxy group and a hydroxy group.

_Ma represents a first polymerizable group. As the first polymerizable group, the following formulas (M _a -1) to (M _a -2) (wherein R ₁ represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms), α-methylene - radically polymerizable groups of γ-butyrolactone, maleimide, norbornene and its derivatives, siloxanes. Formulas (M _a -1) to (M _a -2) and α-methylene-γ-butyrolactone maleimide are preferred.

Examples of the divalent linking group for S _a in the formula (a-1-m) include an alkanediyl group having 1 to 10 carbon atoms (preferably 1 to 6), 6 to 20 carbon atoms (preferably 6 to 14), (*A)-CONH-R ₆ -(*B) group, (*A)-COO-R ₇ -(*B) group and the like. Here, R ₆ and R ₇ are each independently a single bond, an alkanediyl group having 1 to 12 carbon atoms (preferably 1 to 6), or an arylene group having 6 to 20 carbon atoms (preferably 6 to 14). represents a group, an alkyleneoxyarylene group, any carbon-carbon bond of the alkanediyl group may have an -O- bond, and (*A) is a bond that bonds to a carbon atom having an unsaturated bond (*B) indicates that it is a bond that binds to _Ia1 . Examples of alkanediyl groups include methylene group, ethylene group, ethane-1,1-diyl group, propane-1,1-diyl group, propane-1,2-diyl group, propane-1,3-diyl group, Propane-2,2-diyl group, butane-1,2-diyl group, butane-1,3-diyl group, butane-1,4-diyl group, pentane-1,4-diyl group, pentane-1,5 -diyl group, hexane-1,5-diyl group, hexane-1,6-diyl group and the like. Moreover, as an arylene group, a phenylene group, a naphthylene group, a biphenylene group, an anthrylene group, etc. can be mentioned, for example. Examples of the alkyleneoxyarylene group include an ethyleneoxyphenylene group, a hexyleneoxyphenylene group, and a hexyleneoxybiphenyl group. Among them, the divalent linking group for S _a includes an alkanediyl group having 1 to 10 carbon atoms (preferably 1 to 6), an arylene group having 6 to 20 carbon atoms (preferably 6 to 14), (*A) A --COO--R ₇ --(*B) group is preferred, and R ₇ is preferably an alkanediyl group having 2 to 6 carbon atoms.

Specific examples of the above formula (a-1-m) having a carboxy group include (meth)acrylic acid, carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, crotonic acid, isocrotonic acid, α-ethyl acrylic acid, β-ethylacrylic acid, β-propylacrylic acid, β-isopropylacrylic acid, itaconic acid, fumaric acid, vinylbenzoic acid and the like. Further, specific examples of the above formula (a-1-m) having an amino group include tert-butylaminoethyl (meth)acrylate. Specific examples of the formula (a-1-m) having a hydroxy group include 2-hydroxyethyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 4-hydroxy hydroxyalkyl (meth)acrylates such as butyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, 12-hydroxylauryl (meth)acrylate; Hydroxyethyl (meth)acrylamide, (4-hydroxymethylcyclohexyl)methyl acrylate, N-methylol (meth)acrylamide, N-hydroxy (meth)acrylamide and the like can be mentioned.

Specific examples of the above formula (a-1-m) having a group having the partial structure of the above formula (a2) include 2,2,6,6-tetramethyl-4-piperidyl methacrylate and the like. .

The site having a polar group to be contained in the polymer of the present invention may be used singly, or two or more sites may be used in combination.

In addition, the portion having a polar group is preferably contained in a ratio of 20 to 94 mol%, 20 to 88 mol%, or 25 to 80 mol% of the specific polymer (component (A)).

<(A-2) Structure Having Photoalignment Group 1>
The specific polymer contained in the liquid crystal aligning agent of the present invention has a structure having a photo-aligning group 1 represented by the formula (pa-1) in the molecule, preferably in the side chain.
By making the structure of the site having the photo-alignment group 1 as described above, the ability to control vertical alignment can be stably maintained for a long period of time even when exposed to external stress such as heat. In addition, since it has a high sensitivity to light, it is possible to exhibit alignment controllability even with a low exposure dose of polarized ultraviolet irradiation, which is also preferable from the viewpoint of simplifying the manufacturing process of the liquid crystal alignment film.

In the present invention, the site having the photoalignable group 1 represented by the above formula (pa-1) can be represented, for example, by the following formula (b-1). In addition, the site includes, but is not limited to, a structure derived from a monomer represented by the following formula (b-1-m).

In the formula, _Ib is a monovalent organic group represented by 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 (which is optionally one cyano group or substituted with one or more halogen atoms), pyrimidine-2,5-diyl, pyridine-2,5-diyl, thiophene-2,5-diyl, furan-2,5 -diyl, 1,4- or 2,6-naphthylene or phenylene, R ₁ is a single bond, an oxygen atom, -COO- or -OCO-, R ₂ is a divalent aromatic group, a divalent an alicyclic group, a divalent heterocyclic group or a divalent condensed 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 including a linear or branched alkyl group or alicyclic group, and D is an oxygen atom, a sulfur atom or —NR _d — (wherein R _d is , representing a hydrogen atom or alkyl having 1 to 3 carbon atoms), X and Y each independently represent a hydrogen atom, a fluorine atom, a chlorine atom, a cyano group or an alkyl group having 1 to 3 carbon atoms, a is an integer from 0 to 3. When a is 2 or more, each of the plurality of R ₁ and R ₂ independently has the above definition.

In the above formula (b-1) or (b-1-m), S _b represents a spacer unit, and the left bond of S _b binds to the main chain of the specific polymer, optionally via a spacer. indicates that
_Sb can be represented, for example, by the structure of the following formula (Sp).

In formula (Sp),
The left bond of _W1 represents the bond to _Md ,
The right bond of _W3 represents the bond to _Ib ,
W ₁ , W ₂ and W ₃ each independently represent a single bond, a divalent heterocyclic ring, —(CH ₂ ) _n — (wherein 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- but one or more of the non-adjacent CH ₂ groups in these substituents 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 ═CH—, —C≡C— or —O—CO—O— (wherein R independently represents hydrogen or a linear or branched alkyl group having 1 to 5 carbon atoms) can be
A ₁ and A ₂ are each independently a group selected from a single bond, an alkylene group, a divalent aromatic group, a divalent alicyclic group, or a divalent heterocyclic group; The groups may be unsubstituted or one or more hydrogen atoms may be replaced by fluorine, chlorine, cyano, methyl or methoxy groups.

In formula (b-1-m), M _c represents a second polymerizable group. As the second polymerizable group, radically polymerizable groups of (meth)acrylate, fumarate, maleate, α-methylene-γ-butyrolactone, styrene, vinyl, maleimide, norbornene, (meth)acrylamide and derivatives thereof, and siloxane can be mentioned. (Meth)acrylate, α-methylene-γ-butyrolactone, styrene, vinyl, maleimide and acrylamide are preferred.
r ₂ is an integer that satisfies 1≦r ₂ ≦3. When r ₂ is 2 or more, each of the plurality of S _b and I _b independently has the above definition.
In formula (b-1-m), M _d is a single bond, (r ₂ +1)-valent heterocyclic ring, (r ₂ +1)-valent linear or branched hydrocarbon group having 1 to 10 carbon atoms, A group selected from (r ₂ +1)-valent aromatic groups and (r ₂ +1)-valent alicyclic groups, each group being unsubstituted or having at least one hydrogen atom of fluorine atom or chlorine It may be substituted by atoms, cyano groups, methyl groups or methoxy groups.

Examples of aromatic groups for A ₁ , A ₂ and M _d include aromatic hydrocarbon groups having 6 to 18 carbon atoms such as benzene ring, biphenyl structure and naphthalene ring. Examples of the alicyclic group for A ₁ , A ₂ and M _d include alicyclic hydrocarbon groups having 6 to 12 carbon atoms such as cyclohexane ring and bicyclohexane structure. Examples of heterocyclic rings for A ₁ , A ₂ and _Md include nitrogen-containing heterocyclic rings such as pyridine ring, piperidine ring and piperazine ring. Examples of the alkylene group for A ₁ and A ₂ include a linear or branched alkylene group having 1 to 10 carbon atoms.

From the viewpoint of exhibiting good vertical alignment controllability and a stable pretilt angle, the structure of (b-1) is the group represented by (pa-1) above, or the group represented by (pa-1-a) below. can be mentioned. In addition, the site includes, but is not limited to, a structure derived from a monomer represented by the following formula (pa-1-ma).

In the formula, M _c , M _d , S _b and r ₂ have the same definitions as above.
Also, 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-.
_R2 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 C 3-40 monovalent organic group including a C 1-40 linear or branched alkyl group 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 of 0-3 and b is an integer of 0-4. When a is 2 or more, each of the plurality of R ₁ and R ₂ independently has the above definition. When b is 2 or more, each of the plurality of R ₅ independently has the above definition.

In formula (pa-1-a) or (pa-1-ma), the linear or branched alkylene group having 1 to 10 carbon atoms in S _b is a linear or branched alkylene group having 1 to 8 carbon atoms. is preferably a group such as methylene group, ethylene group, n-propylene group, n-butylene group, tert-butylene group, n-pentylene group, n-hexylene group, n-heptylene group and n-octylene group. .

Examples of divalent aromatic groups for S _b include 1,4-phenylene group, 2-fluoro-1,4-phenylene group, 3-fluoro-1,4-phenylene group, 2,3,5,6-tetra A fluoro-1,4-phenylene group and the like can be mentioned.

In the formula (pa-1-a) or (pa-1-ma), the divalent alicyclic group for S _b is, for example, trans-1,4-cyclohexylene, trans-trans-1,4-bicyclohexylene Silene and the like can be mentioned.

Examples of divalent heterocyclic groups for S _b include 2,5-pyridylene group, 2,6-pyridylene group, furan-2,5-diyl group, piperazine-1,4-diyl group, piperidine-1,4 -diyl group and the like.

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

Examples of divalent aromatic groups 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 A fluoro-1,4-phenylene group, a naphthylene group and the like can be mentioned.

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

Examples of divalent heterocyclic groups for R ₂ include 2,5-pyridylene group, 2,6-pyridylene group, furan-2,5-diyl group, piperazine-1,4-diyl group, piperidine-1,4 -diyl group and the like.

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

The linear or branched alkyl group having 1 to 40 carbon atoms for R ₄ includes, for example, a linear or branched alkyl group having 1 to 20 carbon atoms. Or all may be substituted by fluorine atoms. Examples of such alkyl groups include methyl, ethyl, n-propyl, n-butyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, 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- (Perfluorobutyl)ethyl group, 2-(perfluorooctyl)ethyl group, 2-(perfluorodecyl)ethyl group and the like can be mentioned.

Examples of the monovalent organic group having 3 to 40 carbon atoms including an alicyclic group for R ₄ include cholestenyl group, cholestanyl group, adamantyl group, and the following formula (Alc-1) or (Alc-2) (wherein, Each R ₇ is a hydrogen atom, a fluorine atom or an alkyl group having 1 to 20 carbon atoms which may be substituted with a fluorine atom).

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

The site of the photoreactive group 1 to be contained in the polymer of the present invention may be used singly, or two or more sites may be used in combination.

In addition, the site of the photoreactive group 1 is preferably contained in a proportion of 5 to 50 mol%, 10 to 50 mol%, or 15 to 50 mol% of the specific polymer (component (A)).

<(A-3) Portion Having a Thermally Crosslinkable Group>
The specific polymer contained in the liquid crystal aligning agent of the present invention is a site having a thermally crosslinkable group, that is, an oxetanyl group (1,3-epoxy structure), an oxiranyl group (1,2-epoxy structure), the following formula It has a site having at least one functional group selected from a group represented by formula (3), a group represented by formula (4) below, a group represented by formula (5) below, and a thiirane group. In other words, the specific polymer is an oxetanyl group, an oxiranyl group, a group represented by the following formula (3), a group represented by the following formula (4), a group represented by the following formula (5), and a thiirane group. It has a site having at least one selected functional group in the molecule, preferably in a side chain.

The site (A-3) having a thermally crosslinkable group can form a cross-linking reaction with the polar groups such as amino groups, hydroxy groups, and carboxy groups. It is possible to obtain a liquid crystal alignment film excellent in pretilt angle expression ability by stabilizing the liquid crystal alignment ability of the portion having photo-alignment (A-2).

In the present invention, the site having a thermally crosslinkable group can be represented, for example, by the following formula (c-1). Further, the site can include a structure derived from a monomer represented by the following formula (c-1-m).

In formula (c-1) or (c-1-m), I _c is an oxetanyl group, an oxiranyl group, a group represented by the above formula (3), a group represented by the above formula (4), the above formula It is a monovalent organic group selected from the group represented by (5) and a thiirane group. _Sc represents a single bond or a divalent linking group.
In formula (c-1-m), M _e represents a third polymerizable group. Examples of the third polymerizable group include the following formulas (M _c -1) to (M _c -2), radically polymerizable groups of α-methylene-γ-butyrolactone, maleimide, norbornene and derivatives thereof, and siloxane. can.

In formulas (M _c -1) to (M _c -2), Rc represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms.
M _e is preferably represented by formulas (M _c -1) to (M _c -2) and α-methylene-γ-butyrolactone maleimide.

Examples of the divalent linking group for S _c in the formula (c-1-m) include an alkanediyl group having 1 to 10 carbon atoms (preferably 1 to 6), 6 to 20 carbon atoms (preferably 6 to 14), (*A)-CONH-R ₆ -(*B) group, (*A)-COO-R ₇ -(*B) group and the like. Here, R ₆ and R ₇ are each independently a single bond, an alkanediyl group having 1 to 12 carbon atoms (preferably 1 to 6), or an arylene group having 6 to 20 carbon atoms (preferably 6 to 14). represents an alkyleneoxyarylene group, any carbon-carbon bond of the alkanediyl group may have an -O- bond or a -S- bond, and (*A) is a carbon atom having an unsaturated bond (*B) indicates a bond that binds to _Ia1 . Examples of alkanediyl groups include methylene group, ethylene group, ethane-1,1-diyl group, propane-1,1-diyl group, propane-1,2-diyl group, propane-1,3-diyl group, Propane-2,2-diyl group, butane-1,2-diyl group, butane-1,3-diyl group, butane-1,4-diyl group, pentane-1,4-diyl group, pentane-1,5 -diyl group, hexane-1,5-diyl group, hexane-1,6-diyl group and the like. Moreover, as an arylene group, a phenylene group, a naphthylene group, a biphenylene group, an anthrylene group, etc. can be mentioned, for example. Examples of the alkyleneoxyarylene group include an ethyleneoxyphenylene group, a hexyleneoxyphenylene group, and a hexyleneoxybiphenyl group. Among them, the divalent linking group for S _a includes an alkanediyl group having 1 to 10 carbon atoms (preferably 1 to 6), an arylene group having 6 to 20 carbon atoms (preferably 6 to 14), (*A) A --COO--R ₇ --(*B) group is preferred, and R ₇ is preferably an alkanediyl group having 2 to 6 carbon atoms. In each group, one or more hydrogen atoms may be substituted with a fluorine atom, a chlorine atom, a cyano group, a methyl group or a methoxy group.

Specific examples of formula (c-1-m) having an oxiranyl group include allyl glycidyl ether, glycidyl acrylate, glycidyl methacrylate, 2-methylglycidyl methacrylate, α-ethyl glycidyl acrylate, and α-n-propyl. glycidyl acrylate, α-n-butyl glycidyl acrylate, 3,4-epoxybutyl acrylate, 3,4-epoxybutyl methacrylate, 6,7-epoxyheptyl acrylate, 6,7-epoxyheptyl methacrylate, α -6,7-epoxyheptyl ethyl acrylate, 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-hexene, 1,7-octadiene monoepoxide and the like. Among these, glycidyl methacrylate, 2-methylglycidyl methacrylate, 6,7-epoxyheptyl methacrylate, o-vinylbenzyl glycidyl ether, m-vinylbenzyl glycidyl ether, p-vinylbenzyl glycidyl ether, methacrylic acid 3, 4-Epoxycyclohexyl is preferable from the viewpoint of improving the copolymerization reactivity and the orientation of the liquid crystal alignment film.

Specific examples of formula (c-1-m) having an oxetanyl group include 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)-2,2,4-trifluorooxetane, 3-(2-acryloyloxyethyl)-2,2,4,4-tetrafluorooxetane and the like Acrylic acid ester; 3-(methacryloyloxymethyl) oxetane, 3-(methacryloyloxymethyl)-2-methyloxetane, 3-(methacryloyloxymethyl)-3-ethyloxetane, 3-(methacryloyloxymethyl)-2-tri fluoromethyloxetane, 3-(methacryloyloxymethyl)-2-pentafluoroethyloxetane, 3-(methacryloyloxymethyl)-2-phenyloxetane, 3-(methacryloyloxymethyl)-2,2-difluorooxetane, 3-( methacryloyloxymethyl)-2,2,4-trifluorooxetane, 3-(methacryloyloxymethyl)-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-methacryloyloxy ethyl)-2-pentafluoroethyloxetane, 3-(2-methacryloyloxyethyl)-2-phenyloxetane, 3-(2-methacryloyloxyethyl)-2,2-difluorooxetane, 3-(2-methacryloyloxyethyl )-2,2,4-trifluorooxetane and 3-(2-methacryloyloxyethyl)-2,2,4,4-tetrafluorooxetane.

Specific examples of the formula (c-1-m) having a thiirane group include the following formula (S) (where X is —O(CH ₂ ) _n —, —S(CH ₂ ) _n —, or —( CH ₂ ) _n —, where n is an integer of 0 to 6, and Y is an acryloyl group, a methacryloyl group, an allyl group, or a vinyl group.), or 2,3-epithiopropyl acrylate or methacrylate, and 2- or 3- or 4-(β-epithiopropylthiomethyl)styrene, 2- or 3- or 4-(β-epithiopropyloxymethyl)styrene, 2- or 3- or 4- (β-epithiopropylthio)styrene, 2- or 3- or 4-(β-epithiopropyloxy)styrene and the like can be mentioned.

The site having a thermally crosslinkable group to be contained in the polymer of the present invention may be used singly or in combination of two or more types.
The introduction amount of the site having a thermally crosslinkable group is preferably 1 to 30 mol %, 2 to 30 mol %, or 5 to 25 mol % of the specific polymer (component (A)).

<(A-4) Structure Having Photoalignment Group 2>
The specific polymer contained in the liquid crystal aligning agent of the present invention has a structure having photo-orientation represented by the formula (pa-2) in the molecule, preferably in the side chain.
By making the structure of the site having the photo-alignment group 2 as described above, the ability to control vertical alignment can be stably maintained for a longer period of time even when exposed to external stress such as heat.

In the present invention, the site having photoalignment represented by the above formula (pa-2) can be represented by, for example, the following formula (d-1). In addition, the site includes, but is not limited to, a structure derived from a monomer represented by the following formula (d-1-m).

In the formula, I _d is a monovalent organic group represented by the above formula (pa-2).
In the above formula (d-1) or (d-1-m), S _d represents a spacer unit, and the left bond of S _d binds to the main chain of the specific polymer, optionally via a spacer. indicates that
_Sd can be represented, for example, by the structure of the above formula (Sp). However, the left bond of _W1 represents a bond to _Mg , and the right bond of _W3 represents a bond to _Id , but otherwise the same as formula (Sp) above.
In formula (d-1-m), _Mf represents a fourth polymerizable group. As the fourth polymerizable group, radically polymerizable groups of (meth)acrylate, fumarate, maleate, α-methylene-γ-butyrolactone, styrene, vinyl, maleimide, norbornene, (meth)acrylamide and derivatives thereof, and siloxane can be mentioned. (Meth)acrylate, α-methylene-γ-butyrolactone, styrene, vinyl, maleimide and acrylamide are preferred.
r ₃ is an integer that satisfies 1≦r ₃ ≦3. When r ₃ is 2 or more, each of the plurality of S _d and I _d independently has the above definition.
In formula (d-1-m), M _g is a single bond, (r ₃ +1)-valent heterocyclic ring, (r ₃ +1)-valent linear or branched hydrocarbon group having 1 to 10 carbon atoms, A group selected from (r ₃ +1)-valent aromatic groups and (r ₃ +1)-valent alicyclic groups, each group being unsubstituted or having at least one hydrogen atom of fluorine atom or chlorine It may be substituted by atoms, cyano groups, methyl groups or methoxy groups.

Examples of the aromatic group for _Mg include aromatic hydrocarbon groups having 6 to 18 carbon atoms such as benzene ring, biphenyl structure and naphthalene ring. Examples of the alicyclic group for _Mg include alicyclic hydrocarbon groups having 6 to 12 carbon atoms such as cyclohexane ring and bicyclohexane structure. Examples of the heterocyclic ring in _Mg include nitrogen-containing heterocyclic rings such as pyridine ring, piperidine ring and piperazine ring.

From the viewpoint of being able to exhibit good vertical alignment controllability and a stable pretilt angle, the structure of (d-1) is the group represented by (pa-2) above, or the group represented by (pa-2-a) below. can be mentioned. In addition, the site includes, but is not limited to, a structure derived from a monomer represented by the following formula (pa-2-ma). In the following formula, M _f , M _g , S _d , L ₁ , R ₁₁ and r ₃ have the same definitions as above.

In formula (pa-2-a) or (pa-2-ma), the linear or branched alkylene group having 1 to 10 carbon atoms in S _d is a linear or branched alkylene group having 1 to 8 carbon atoms. is preferably a group such as methylene group, ethylene group, n-propylene group, n-butylene group, t-butylene group, n-pentylene group, n-hexylene group, n-heptylene group and n-octylene group. .

Examples of divalent aromatic groups for S _d include 1,4-phenylene group, 2-fluoro-1,4-phenylene group, 3-fluoro-1,4-phenylene group, 2,3,5,6-tetra A fluoro-1,4-phenylene group and the like can be mentioned.

In formula (pa-2-a) or (pa-2-ma), the divalent alicyclic group of S _d is, for example, trans-1,4-cyclohexylene group, trans-trans-1,4-bi A cyclohexylene group and the like can be mentioned.

Examples of divalent heterocyclic groups for S _d include 2,5-pyridylene group, 2,6-pyridylene group, furan-2,5-diyl group, piperazine-1,4-diyl group, piperidine-1,4 -diyl group and the like.

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

R ₁₁ includes a methoxy group, ethoxy group, n-propyloxy group, n-butyloxy group, tert-butyloxy group, n-pentyloxy group, trifluoromethyl group, fluoro group, chloro group, bromo group, cyano group, A nitro group and the like can be mentioned.

Examples of the monomer represented by the above formula (pa-2-ma) include, but are not limited to, structures represented by formulas (paa-2-ma1) to (paa-2-ma7). In the formula, "E" represents the E form.

The site of the photoreactive group 2 to be contained in the polymer of the present invention may be used singly, or two or more sites may be used in combination.

In addition, the site of the photoreactive group 2 is preferably contained in a ratio of 1 to 20 mol%, 2 to 15 mol%, or 3 to 10 mol% of the specific polymer (component (A)).

<Solvent>
The solvent used for the liquid crystal aligning agent of the present invention is not particularly limited as long as it dissolves the specific polymer.
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 Dialkylimidazolidinones 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, methyl isobutyl ketone, 4-hydroxy-4-methyl-2-pentanone, the following formula Compounds represented by (Sv-1) and compounds represented by the following formula (Sv-2), 4-methyl-2-pentyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, cyclohexyl acetate, 2-methyl acetate Cyclohexyl, butyl butyrate, isoamyl butyrate, diisobutylcarbinol, diisopentyl ether and the like can be mentioned.

In formulas (Sv-1) and (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- , X ₂ 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 of 1-3. When n ₁ is 2 or 3, multiple R _1s may be the same or different. Z ₁ is a C 1-6 divalent hydrocarbon group, and Y ₃ and Y ₄ are each independently a hydrogen atom or a C 1-6 monovalent hydrocarbon group.

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

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

Specific examples of the solvent represented by formula (Sv-1) include, for example, 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 and the like;
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. Preferred solvents include N,N-dimethylformamide, tetramethylurea, 3-methoxy-N,N-dimethylpropanamide, propanol, isopropanol, 3-methyl-3-methoxy Butanol, ethyl amyl ketone, methyl ethyl ketone, isoamyl methyl ketone, methyl isopropyl ketone, diisobutyl ketone, cyclohexanone, 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, diisobutylcarbinol, 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, ethyl-3- ethoxypropionate, methyl-3-methoxypropionate, ethyl 3-methoxypropionate, and the like. It is preferable that the boiling point is within this range, particularly when the liquid crystal aligning agent containing the solvent is applied onto a plastic substrate, which will be described later.

<Method for producing specific polymer>
The specific polymer contained in the liquid crystal aligning agent of the present invention includes (A-1) a monomer having at least one functional group selected from the above carboxy group, amino group and hydroxy group, and (A-2) light Obtained by polymerizing a monomer having a site having an alignment group 1, (A-3) a monomer having a thermally crosslinkable group, and (A-4) a monomer having a site having a photoalignment group 2. . Moreover, it can be copolymerized with other monomers other than those described above. Other monomers include, for example, industrially available radical polymerizable monomers.

Specific examples of other monomers include acrylic acid ester compounds, methacrylic acid ester compounds, maleimide compounds, acrylonitrile, maleic anhydride, styrene compounds and vinyl compounds, etc., containing a nitrogen-containing aromatic heterocyclic group and a polymerizable group. monomers.

Examples of acrylic acid 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, tert-butyl acrylates, cyclohexyl acrylate, isobornyl acrylate, 2-methoxyethyl acrylate, methoxytriethylene glycol acrylate, 2-ethoxyethyl acrylate, tetrahydrofurfuryl acrylate, 3-methoxybutyl acrylate, 2-methyl-2-adamantyl acrylate, 2- Propyl-2-adamantyl acrylate, 8-methyl-8-tricyclodecyl acrylate, 8-ethyl-8-tricyclodecyl acrylate and the like.

Examples of methacrylic acid ester compounds include alkyl group-containing methacrylates such as methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, hexadecyl methacrylate and octadecyl methacrylate, benzyl methacrylate, naphthyl methacrylate, anthryl methacrylate, anthrylmethyl methacrylate, phenyl methacrylate, 2 , 2,2-trifluoroethyl methacrylate, tert-butyl methacrylate, cyclohexyl methacrylate, isobornyl methacrylate, 2-methoxyethyl methacrylate, methoxytriethylene glycol methacrylate, 2-ethoxyethyl methacrylate, tetrahydrofurfuryl methacrylate, 3-methoxybutyl methacrylate, 2-methyl-2-adamantyl methacrylate, 2-propyl-2-adamantyl methacrylate, 8-methyl-8-tricyclodecyl methacrylate, 8-ethyl-8-tricyclodecyl methacrylate and the like.

Examples of vinyl compounds include vinyl ether, methyl vinyl ether, benzyl vinyl ether, 2-hydroxyethyl vinyl ether, phenyl vinyl ether, and propyl vinyl ether.

Styrene compounds include, for example, styrene, methylstyrene, chlorostyrene, bromostyrene, and the like.

The nitrogen-containing aromatic heterocycle has a structure selected from the group consisting of the following formulas [Na] to [Nb] (wherein Z ₂ is a linear or branched alkyl group having 1 to 5 carbon atoms) is preferably an aromatic cyclic hydrocarbon containing at least 1, preferably 1 to 4 of.

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, an acridine ring, and the like. Furthermore, the carbon atoms of these nitrogen-containing aromatic heterocycles may have substituents containing heteroatoms. Among these, a pyridine ring is mentioned, for example.

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 singly, or two or more moieties may be used in combination.

The content of the above other monomers is preferably 0 to 20 mol%, or 1 to 20 mol%, or 5 to 20 mol% of the specific polymer (component (A)). In this case, the total of the site having a polar group, the site of photoreactive group 1, the site having thermal crosslinkability and the site of photoreactive group 2 is 80 to 100 mol% of the specific polymer (A) component, or 80 to 99 mol %, or 80 to 95 mol %.

The method for producing the specific polymer in the present invention is not particularly limited, and general-purpose industrially used methods can be used. Specifically, it can be produced by cationic polymerization, radical polymerization, or anionic polymerization using a vinyl group of a monomer. 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. Examples of such radical thermal polymerization initiators include 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 (dibutylperoxycyclohexane etc.), 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.), azo compounds (azobisisobutyronitrile, 2,2'-di(2-hydroxyethyl)azobisisobutyronitrile, etc.). Such radical thermal polymerization initiators can be used singly 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 an emulsion polymerization method, a suspension polymerization method, a dispersion polymerization method, a precipitation polymerization method, a bulk polymerization method, a solution polymerization method, or the like can be used.

The solvent used for the polymerization reaction of the specific polymer is not particularly limited as long as it dissolves the polymer produced. Specific examples include the above solvents such as N-alkyl-2-pyrrolidones, dialkylimidazolidinones, lactones, carbonates, ketones, compounds represented by the above formula (Sv-1) and the above formulas compounds represented by (Sv-2), tetrahydrofuran, 1,4-dioxane, dimethylsulfone, dimethylsulfoxide, hexamethylsulfoxide and the like.

These solvents may be used alone or in combination. Furthermore, even a solvent that does not dissolve the resulting polymer may be used by mixing with the above solvent.

Also, in radical polymerization, oxygen in the solvent inhibits 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 may be any temperature from 30 to 150°C, preferably from 50 to 100°C. Also, 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 the organic solvent can be added.

In the radical polymerization reaction described above, the ratio of the radical initiator is preferably 0.1 to 10 mol% with respect to the monomers to be polymerized. Further, various monomer components, solvents, initiators, etc. can be added during polymerization.

[Recovery of polymer]
In the case of recovering the produced polymer from the reaction solution obtained by the above reaction, the reaction solution may be put into a poor solvent to precipitate the polymer. Poor solvents used for precipitation include methanol, acetone, hexane, heptane, butyl cellosolve, heptane, ethanol, toluene, benzene, diethyl ether, methyl ethyl ether, and water. The polymer precipitated by putting it into a poor solvent can be filtered and recovered, and then dried at room temperature or under heat under normal pressure or reduced pressure. In addition, the impurities in the polymer can be reduced by redissolving the precipitated and recovered polymer in an organic solvent and repeating the operation of reprecipitating and recovering 2 to 10 times. Examples of the poor solvent in this case include alcohols, ketones, hydrocarbons, and the like. It is preferable to use three or more poor solvents selected from these, because the purification efficiency is further improved.

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

[Preparation of Liquid Crystal Aligning Agent]
The liquid crystal aligning agent (that is, polymer composition) used in the present invention is preferably prepared as a coating liquid so as to be suitable for forming a liquid crystal aligning 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 already explained specific polymer (component (A)). At that time, the content of the resin component is preferably 0.5 to 20% by mass, more preferably 1 to 15% by mass, particularly preferably 1 to 10% by mass, based on the total liquid crystal aligning agent.

In the polymer composition of the present embodiment, the above-mentioned resin components include a site having a polar group, a site having a photo-aligning group 1, a site having a thermally crosslinkable group, and a photo-aligning group. 2 may be used, but other polymers (hereinafter also referred to as "other polymers") may be mixed. At that time, the content of the other polymer in the resin component may be 5 to 95 parts by mass, or 10 to 90 parts by mass, based on the total of 100 parts by mass of the component (A) and the other polymer. .

Such other polymers are composed of, for example, poly(meth)acrylates, polyamic acid esters, polyimides, etc., and some or all of (A-1) to (A-4) possessed by the specific polymer of the present invention and polymers having no site.

<Other ingredients>
The liquid crystal aligning agent of the present invention may contain components other than the characteristic polymer component. Such other components include compounds containing two or more epoxy groups or thiirane groups in the molecule and other crosslinkable compounds (hereinafter collectively referred to as "crosslinker components"), and liquid crystals. Compounds that improve film thickness uniformity and surface smoothness when the alignment agent is applied, compounds that improve adhesion between the liquid crystal alignment film and the substrate, and the like can be mentioned, but are not limited to these.

<Crosslinking agent component>
1. A compound containing two or more epoxy groups or thiirane groups in the molecule By making such a structure, the amino group, hydroxy group, or carboxy group that is the polar group of (A-1) contained in the above specific polymer And the cross-linking reaction with the hydroxy group is further accelerated, and it becomes possible to obtain a liquid crystal alignment film excellent in the pretilt angle expression ability even in short-time baking. Compounds having two or more epoxy groups or thiirane groups in the molecule are not particularly limited as long as they have two or more epoxy groups or thiirane groups at the ends of the molecule. Examples of compounds having two or more epoxy groups at the ends of the molecules include epoxy compounds having at least one or more tertiary nitrogen atoms in the molecule, epoxy compounds having no nitrogen compound in the molecule, and the like. can.

Specific examples of epoxy compounds having at least one tertiary nitrogen atom in the molecule include epoxy compounds and aliphatic diamines having structures represented by the following formulas (Ep-1) to (Ep-11). Examples thereof include epoxy compounds containing a nitrogen atom as a mother nucleus. In the following formula, each X represents a single bond, an aliphatic group having 1 to 6 carbon atoms, or an aromatic group, and Y represents a methylene group, an ethylene group, a trimethylene group, an ethylidene group, an isopropylidene group, and a vinylene group. , a vinylidene group, an oxy group, an imino group, a thio group, or a sulfonyl group, each of R ₁ to R ₃ independently represents a hydrogen atom or an aliphatic group having 1 to 6 carbon atoms, and j is Represents an integer from 0 to 4. When j is 2 or more, multiple R _1s may be the same or different. Q ₁ to Q ₃ each independently represent an alkylene group having 1 to 6 carbon atoms.

Among epoxy compounds having at least one or more tertiary nitrogen atoms in the molecule, compounds in which the tertiary nitrogen atom is bonded to at least one aliphatic group or alicyclic group shorten the baking time. It is preferable in that it is possible.

Specific examples of epoxy compounds having at least one or more tertiary nitrogen atoms in the molecule include N,N-diglycidylaniline, N,N-diglycidyltoluidine, N,N-diglycidylcyclohexylamine, N, N-diglycidylmethylcyclohexylamine, N,N,N',N'-tetraglycidyl-p-phenylenediamine, N,N,N',N'-tetraglycidyl-m-phenylenediamine, N,N,N' , N′-tetraglycidyl-o-phenylenediamine, N,N,N′,N′-tetraglycidyl-4,4′-diaminodiphenylmethane, N,N,N′,N′-tetraglycidyl-3,4′ -diaminodiphenylmethane, N,N,N',N'-tetraglycidyl-3,3'-diaminodiphenylmethane, N,N,N',N'-tetraglycidyl-4,4'-diaminodiphenyl sulfide, N,N , N′,N′-tetraglycidyl-1,5-diaminonaphthalene, N,N,N′,N′-tetraglycidyl-2,7-diaminofluorene, N,N,N′,N′-tetraglycidyl- 4,4'-diaminodiphenyl ether, N,N,N',N'-tetraglycidyl-2,2-bis[4-(4-aminophenoxy)phenyl]propane, N,N,N',N'-tetra glycidyl-9,9-bis(4-aminophenyl)fluorene, N,N,N',N'-tetraglycidyl-2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane, N, N,N',N'-tetraglycidyl-2,2-bis(4-aminophenyl)hexafluoropropane, N,N,N',N'-tetraglycidyl-4,4'-(p-phenylenediisopropyl bisaniline, N,N,N',N'-tetraglycidyl-4,4'-(m-phenylenediisopropylidene)bisaniline, N,N,N',N'-tetraglycidyl-1,4-bis (4-aminophenoxy)benzene, N,N,N',N'-tetraglycidyl-4,4'-bis(4-aminophenoxy)biphenyl, N,N,N',N'-tetraglycidyl-m- xylylenediamine, N,N,N',N'-tetraglycidyl-p-xylylenediamine, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, 1,4-bis(N,N- diglycidylaminomethyl)cyclohexane, N,N,N',N'-tetraglycidyl-1,4-cyclohexanediamine, N,N,N',N'-tetraglycidyl-1,3-cyclohexanediamine, N,N , N′,N′-tetraglycidyl-4,4′-methylenebis(cyclohexylamine), N,N,N′,N′-tetraglycidyl-1,2-diaminoethane, N,N,N′,N′ -tetraglycidyl-1,3-diaminopropane, N,N,N',N'-tetraglycidyl-1,4-diaminobutane, N,N,N',N'-tetraglycidyl-1,5-diaminopentane , N,N,N′,N′-tetraglycidyl-1,6-diaminohexane, N,N,N′,N′-tetraglycidyl-1,7-diaminoheptane, N,N,N′,N′ -tetraglycidyl-1,8-diaminooctane and the like.
Specific examples of epoxy compounds having no nitrogen atom in the molecule include trade names of "Epikote 828", "Epikote 834", "Epikote 1001" and "Epikote 1004" manufactured by Mitsubishi Chemical Corporation, and Dainippon Ink and Chemicals. Bisphenol A type epoxy compounds such as "Epiclon 840", "Epiclon 850", "Epiclon 1050", and "Epiclon 2055" manufactured by Nippon Steel & Sumikin Chemical Co., Ltd. under the trade name of "Epotote 128";
Dainippon Ink and Chemicals Co., Ltd. under the trade name of "Epiclon 830S"; Mitsubishi Chemical under the trade name of "Epikote 807"; YDF-2004” and other bisphenol F type epoxy compounds;
Bisphenol S-type epoxy compounds such as the trade name “EBPS-200” manufactured by Nippon Kayaku, the trade name “EPX-30” manufactured by Asahi Denka Kogyo Co., Ltd., and the trade name “Epiclon EXA1514” manufactured by Dainippon Ink and Chemicals;
Bisphenol fluorene-type epoxy compounds such as the trade name “BPFG” manufactured by Osaka Gas Co., Ltd.; bixylenol-type or biphenyl-type epoxy compounds, or mixtures thereof;
Hydrogenated bisphenol A type epoxy compounds such as trade names "Epotote ST-2004", "ST-2007", "ST-3000" manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.;
Trade names "Epikote 152" and "Epikote 154" manufactured by Mitsubishi Chemical Corporation, trade names "DEN 431" and "DEN 438" manufactured by Dow Chemical Co., Ltd., Dainippon Ink and Chemicals Co., Ltd. manufactured by Nippon Steel & Sumikin Chemical Co., Ltd. under the trade names of "Epiclon N-690,""EpiclonN-695,""EpiclonN-730,""EpiclonN-770," and "Epiclon N-865," and "Epotote YDCN" manufactured by Nippon Steel & Sumikin Chemical -701”, “Epotato YDCN-704”, Nippon Kayaku brand names “EPPN-201”, “EOCN-1025”, “EOCN-1020”,
Novolac type epoxy compounds such as "EOCN-104S" and "RE-306";
Mitsubishi Chemical's trade name "Epikote YL-903", Dainippon Ink and Chemicals Co., Ltd. trade names "Epicron 152" and "Epicron 165", Nippon Steel & Sumikin Chemical Co., Ltd. trade names "Epotote YDB-400", " Brominated bisphenol A type epoxy compounds such as Epotato YDB-500;
Naphthalene skeleton such as trade names "ESN-190" and "ESN-360" manufactured by Nippon Steel Chemical Co., Ltd., trade names "HP-4032", "EXA-4700", and "EXA-4750" manufactured by Dainippon Ink and Chemicals Co., Ltd. an epoxy compound having
Epoxy compounds having a dicyclopentadiene skeleton, such as trade names "HP-7200" and "HP-7200H" manufactured by Dainippon Ink and Chemicals;
Tris-hydroxyphenylmethane-type epoxy compounds such as Mitsubishi Chemical's trade name "YL-933" and Nippon Kayaku's trade names "EPPN-501" and "EPPN-502";
Alicyclic epoxy compounds such as the product name "Celoxide 2011" manufactured by Daicel Chemical Industries, Ltd., the product names "Araldite CY175" and "Araldite CY179" manufactured by Asahi Chemical Industries, Ltd., and the product name "HBE-100" manufactured by Shin Nippon Rika Co., Ltd. etc., but not limited to these. These epoxy compounds can be used individually or in combination of 2 or more types.

The compound having two or more thiirane groups at the molecular end can be obtained, for example, by converting the epoxy group of the epoxy compound having the epoxy group to a thiirane group. As a method for converting to the thiirane group, the solution containing the epoxy compound having the epoxy group is continuously or intermittently added to the first solution containing the sulfurizing agent, and then the second solution containing the sulfurizing agent is added. A method of further adding continuously or intermittently is preferred. By this method, the epoxy group can be converted to a thiirane group.

Examples of the sulfurizing agent include thiocyanates, thioureas, phosphine sulfide, dimethylthioformamide and N-methylbenzothiazole-2-thione. Examples of the thiocyanates include sodium thiocyanate, potassium thiocyanate and sodium thiocyanate.

The use of a compound having two or more thiirane groups promotes the cross-linking reaction, which is preferable in that the baking time of the liquid crystal aligning agent can be shortened.
The amount of the compound component containing two or more epoxy groups or thiirane groups in the molecule is 0.1 to 40 parts by mass with respect to 100 parts by mass of the resin component contained in the polymer composition. is preferred, and more preferably 0.5 parts by mass to 20 parts by mass.

2. Other crosslinkable compounds Other crosslinkable compounds include compounds having an isocyanate group, an oxetane group, or a cyclocarbonate group, or a hydroxy group, described in paragraphs [0109] to [0113] of International Publication WO2016/047771. , a compound having at least one group selected from the group consisting of a hydroxyalkyl group and a lower alkoxyalkyl group, and a compound having a blocked isocyanate group.

Examples of blocked isocyanate compounds 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, B-820NSU, B-842N, B-846N, B-870N, B-874N, B-882N (manufactured by Mitsui Chemicals, Inc.) and the like.

The amount of these crosslinking agent components used is preferably 0.1 parts by mass to 30 parts by mass, more preferably 1 part by mass to 20 parts by mass with respect to 100 parts by mass of the resin component contained in the polymer composition. Department.

[Compound that improves film thickness uniformity and surface smoothness]
Compounds that improve film thickness uniformity and surface smoothness include fluorine-based surfactants, silicone-based surfactants, nonionic surfactants, and the like. Specifically, for example, Ftop (registered trademark) 301, EF303, EF352 (manufactured by Tochem Products), Megafac (registered trademark) F171, F173, R-30 (manufactured by DIC), Florard FC430, FC431 ( 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 Co., Ltd.), etc. . The proportion of these surfactants used is preferably 0.01 to 2 parts by mass, more preferably 0.01 to 1 part by mass, per 100 parts by mass of the resin component contained in the polymer composition. part by mass.

[Compound for Improving Adhesion between Liquid Crystal Alignment Film and Substrate]
Specific examples of the compound that improves 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-(3-triethoxysilylpropyl)triethylenetetramine, N-(3-trimethoxysilylpropyl)triethylenetetramine, 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- Amino silane-containing compounds such as 3-aminopropyltrimethoxysilane, N-benzyl-3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltriethoxysilane is mentioned.

When using a compound that improves adhesion to the substrate, the amount used is preferably 0.1 to 30 parts by mass with respect to 100 parts by mass of the resin component contained in the polymer composition. It is more preferably 1 part by mass to 20 parts by mass.

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

<Liquid crystal alignment film and liquid crystal display element>
The liquid crystal aligning agent of the present invention can be coated on a substrate, baked, and then subjected to alignment treatment such as rubbing treatment or light irradiation, or can be used as a liquid crystal alignment film without alignment treatment for some vertical alignment applications. can. Substrates include glass such as float glass and soda glass; polyethylene terephthalate, polybutylene terephthalate, polypropylene, polystyrene, polyethersulfone, polycarbonate, poly(alicyclic olefin), polyvinyl chloride, polyvinylidene chloride, polyether ether A transparent substrate made of plastic such as ketone (PEEK) resin film, polysulfone (PSF), polyethersulfone (PES), polyamide, polyimide, acrylic and triacetylcellulose can be used.

Examples of the transparent conductive film provided on one surface of the substrate include an NESA film (registered trademark of PPG, USA) made of tin oxide (SnO ₂ ), an ITO film made of indium oxide-tin oxide (In ₂ O ₃ —SnO ₂ ), and the like. can be used.

<Coating film forming process>
The method of applying the liquid crystal aligning agent of the present invention is not particularly limited. good. After coating on a substrate by these methods, a coating film can be formed by evaporating the solvent by heating means such as a hot plate.

Baking after applying the liquid crystal aligning agent can be performed at any temperature of 40 to 300°C, preferably 40 to 250°C, more preferably 40 to 230°C. When a transparent substrate made of a plastic substrate is used, the temperature is preferably 40 to 150.degree. C., more preferably 80 to 140.degree. The firing time is preferably 0.1 to 15 minutes, more preferably 1 to 10 minutes.

The film 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 baking can be performed using a hot plate, a hot air circulating furnace, an infrared furnace, or the like.

Rayon cloth, nylon cloth, cotton cloth, etc. can be used for the rubbing treatment.

<Light irradiation process>
In an embodiment, alignment treatment may be performed by light irradiation, for example, a step of applying the above liquid crystal alignment agent on a substrate to form a coating film, and the coating film is not in contact with the liquid crystal layer or and irradiating the coating film with light while in contact with the liquid crystal layer.

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

When the light used is polarized light, the light irradiation may be performed in a direction perpendicular to the substrate surface or in an oblique direction, or may be performed in combination. When irradiating with non-polarized light, it is preferable to irradiate from an oblique direction with respect to the substrate surface.

The irradiation amount of light 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 further preferably 2 to 200 mJ/cm ² . preferable.

The liquid crystal display element of the present invention can be produced by a normal method, and the production method is not particularly limited. It is preferable that the pair of substrates are opposed to each other with an appropriate gap therebetween, and a spacer is arranged between the substrates for the purpose of uniformizing the thickness of the liquid crystal sandwiched between the substrates. As the spacer, known spacer materials such as a conventional spray-type spacer and a spacer formed from a photosensitive spacer-forming composition can be used. It can also be used as a spacer.

<Liquid crystal clamping process>
There are, for example, the following two methods for forming a liquid crystal cell by sandwiching liquid crystal between substrates. As a first method, a pair of substrates are arranged opposite to each other with a gap (cell gap) interposed between the liquid crystal alignment films, and the peripheral portions of the pair of substrates are bonded together using a sealing agent, and the substrate surfaces and A liquid crystal cell can be produced by injecting and filling a liquid crystal into a cell gap partitioned by an appropriate sealant and then sealing the injection hole.

As a second method, for example, an ultraviolet light-curing sealing material is applied to a predetermined place on one of the two substrates on which the liquid crystal alignment film is formed, and several predetermined places on the surface of the liquid crystal alignment film are coated. After dropping the liquid crystal on the substrate, the other substrate is attached so that the liquid crystal alignment film faces the other substrate, and the liquid crystal is spread over the entire surface of the substrate. A method of manufacturing a cell (ODF (One Drop Fill) method) can be mentioned.

Liquid crystals include fluorine-based liquid crystals and cyano-based liquid crystals having positive or negative dielectric anisotropy depending on the application, and liquid crystal compounds or liquid crystal compositions ( hereinafter, also referred to as a polymerizable liquid crystal or a curable liquid crystal composition) may be used.

The step of forming the coating film of the liquid crystal aligning agent may be performed by a roll-to-roll method. The roll-to-roll method simplifies the manufacturing process of the liquid crystal display element, thereby making it possible to reduce the manufacturing cost.

Then, 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 outside the liquid crystal cell consists of a polarizing film called "H film", which is made by stretching and aligning polyvinyl alcohol and absorbing iodine, sandwiched between cellulose acetate protective films, or the H film itself. A polarizing plate and the like can be mentioned.

The liquid crystal alignment film obtained from the liquid crystal alignment agent of the present invention as described above has good liquid crystal alignment, excellent pretilt angle expression ability, and high reliability. Also, the liquid crystal display device manufactured by the method of the present invention has excellent display characteristics.

The present invention will be specifically described below with reference to examples, but the present invention should not be construed as being limited to these examples. Abbreviations of compounds and methods for measuring properties are as follows.

<Methacrylic monomer>
(Photo-orientation monomer)
MA-1 was synthesized by the synthesis method described in the patent document (WO2017/115790).
MA-2 was synthesized according to the synthesis method described in British Patent GB2306470B.
The side chain derived from MA-1 has photo-alignment group 1, and the side chain derived from MA-2 has photo-alignment group 2.

(epoxy group-containing monomer)
GMA: glycidyl methacrylate

(Carboxy group-containing monomer)
MAA: methacrylic acid

<Tetracarboxylic dianhydride monomer>
A1 to A3: compounds represented by the following formulas [A1] to [A3], respectively

<Diamine monomer>
B1 to B3: compounds represented by the following formulas [B1] to [B3], respectively

(Crosslinking agent component)
D1: a compound represented by the following formula [D1]

(Polymerization initiator)
AIBN: azobisisobutyronitrile

(solvent)
NMP: N-methyl-2-pyrrolidone BCS: butyl cellosolve THF: tetrahydrofuran

<Molecular weight measurement>
The molecular weights of the polymers in Synthesis Examples were measured using a room temperature gel permeation chromatography (GPC) apparatus (SSC-7200 manufactured by Senshu Kagaku Co., Ltd., columns manufactured by Shodex (KD-803, KD-805)) as follows.
Column temperature: 50° C., eluent: DMF (additives include lithium bromide monohydrate (LiBr.H ₂ O) at 30 mmol/L, phosphoric acid/anhydrous crystals (o-phosphoric acid) at 30 mmol/L, THF is 10 ml / L), flow rate: 1.0 mL / min Standard sample for creating a calibration curve: Tosoh Corporation TSK standard polyethylene oxide (molecular weight about 900,000, 150,000, 100,000, 30,000), and Polyethylene glycol manufactured by Polymer Laboratories (molecular weight: about 12,000, 4,000, 1,000).

<Measurement of imidization rate>
The imidization rate in Synthesis Examples was measured as follows. 20 mg of polyimide powder is placed in an NMR sample tube (manufactured by Kusano Kagaku NMR sampling tube standard φ5), 1.0 mL of deuterated dimethyl sulfoxide (DMSO-d ₆ , 0.05% TMS mixture) is added, and ultrasonic waves are applied. to dissolve completely. This solution was subjected to proton NMR at 500 MHz using an NMR spectrometer (JNW-ECA500) manufactured by JEOL Datum. For the imidization rate, a proton derived from a structure that does not change before and after imidization is determined as a reference proton. It was obtained by the following formula using the integrated value. In the following formula, x is the proton peak integrated value derived from the NH group of the amic acid, y is the peak integrated value of the reference proton, and α is the proton of the NH group of the amic acid in the case of polyamic acid (imidization rate is 0%). It is the ratio of the number of reference protons to one.
Imidation rate (%) = (1-α x/y) x 100

<Synthesis of polymethacrylate>
(Synthesis example 1)
MA-1 (3.04 g, 6.00 mmol), MA-2 (0.44 g, 1.00 mmol), GMA (0.57 g, 4.00 mmol) and MAA (0.77 g, 9.00 mmol) in NMP (28.2 g) and degassed with a diaphragm pump, AIBN (0.16 g, 0.97 mmol) was added as a polymerization initiator and degassed again. After that, reaction was carried out at 60° C. for 13 hours under nitrogen atmosphere to obtain a polymer solution.
Next, NMP (5.0 g) and BCS (6.0 g) were added to this polymer solution (4.0 g) and stirred at room temperature to obtain a polymethacrylate solution (MP1).
This polymer had a number average molecular weight of 31,000 and a weight average molecular weight of 120,000.

(Synthesis Examples 2-3)
Using the same method as in Synthesis Example 1, polymethacrylate solutions (MP2) to (MP3) were synthesized with the compositions shown in Table 1.

<Synthesis of polyamic acid>
(Synthesis Example 4)
B1 (1.22 g, 8.00 mmol), B2 (1.45 g, 6.00 mmol), B3 (2.28 g, 6.00 mmol) and A2 (1.00 g, 4.00 mmol) were combined with NMP (29.2 g). and reacted at 60°C for 5 hours, then A1 (2.24g, 11.4mmol) and A3 (0.87g, 4.00mmol) and NMP (7.3g) were added and stirred at 40°C for 10 hours. A polyamic acid solution (PAA-1A) with a solid content concentration of 20% by mass was obtained by reacting for a period of time.
NMP (20.0 g) and BCS (20.0 g) were added to the obtained polyamic acid solution (10.0 g), and the mixture was stirred at room temperature for 2 hours to obtain a polyamic acid solution having a solid concentration of 4.0% by mass ( PAA-1) was obtained.

<Synthesis of polyimide>
(Synthesis Example 5)
After adding NMP to the polyamic acid solution (PAA-1A) (15 g) and diluting it to a solid content concentration of 6.5% by mass, acetic anhydride (2.6 g) and pyridine (0.81 g) were added as an imidization catalyst, and 75 °C for 2.5 hours. This reaction solution was poured into methanol (210 mL), and the resulting precipitate was filtered off. This precipitate was washed with methanol and dried under reduced pressure at 100° C. to obtain polyimide powder (E). This polyimide had an imidization rate of 75%, a number average molecular weight of 12,400, and a weight average molecular weight of 42,500.
NMP (14.7 g) was added to the obtained polyimide powder (E) (2.0 g) and dissolved by stirring at 70° C. for 20 hours. NMP (13.3 g) and BCS (20.0 g) were added to this solution and stirred at room temperature for 5 hours to obtain a polyimide solution (SPI-1).

<Preparation of liquid crystal aligning agent>
(Example 1)
D1 (0.04 g) was added to the polymethacrylate solution (MP1) (10.0 g) obtained in Synthesis Example 1, and the mixture was stirred at room temperature to obtain a liquid crystal aligning agent (PM1).

(Example 2)
To the polymethacrylate solution (MP1) (3.0 g) obtained in Synthesis Example 1 was added the polyamic solution (PAA-1) (7.0 g) obtained in Synthesis Example 4, and further D1 (0.04 g) was added. The liquid crystal aligning agent (PM2) was obtained by adding and stirring at room temperature.

(Example 3)
The polymethacrylate solution (MP1) (3.0 g) obtained in Synthesis Example 1 was added with the polyimide solution (SPI-1) (7.0 g) obtained in Synthesis Example 5, and D1 (0.04 g) was added. The liquid crystal aligning agent (PM3) was obtained by adding and stirring at room temperature.

(Comparative example 1)
D1 (0.04 g) was added to the polymethacrylate solution (MP2) (10.0 g) obtained in Synthesis Example 2, and the mixture was stirred at room temperature to obtain a liquid crystal aligning agent (RPM1).

(Comparative example 2)
D1 (0.04 g) was added to the polymethacrylate solution (MP3) (10.0 g) obtained in Synthesis Example 3, and the mixture was stirred at room temperature to obtain a liquid crystal aligning agent (RPM2).

(Comparative Example 3)
The polyamic acid solution (PAA-1) (7.0 g) obtained in Synthesis Example 4 was added to the polymethacrylate solution (MP2) (3.0 g) obtained in Synthesis Example 2, and D1 (0.04 g) was added. was added and stirred at room temperature to obtain a liquid crystal aligning agent (RPM3).

(Comparative Example 4)
The polymethacrylate solution (MP2) (3.0 g) obtained in Synthesis Example 2 was added with the polyimide solution (SPI-1) (7.0 g) obtained in Synthesis Example 5, and D1 (0.04 g) was added. The liquid crystal aligning agent (RPM4) was obtained by adding and stirring at room temperature.

<Production of liquid crystal display element>
The liquid crystal aligning agents (PM1) to (PM3) obtained in Examples and the liquid crystal aligning agents (RPM1) to (RPM4) obtained in Comparative Examples were filtered under pressure with a membrane filter having a pore size of 1 μm.
The resulting solution was spin-coated on the ITO surface of a glass substrate with a transparent electrode made of an ITO film, dried on a hot plate at 70° C. for 90 seconds, and then baked on a hot plate at 200° C. for 30 minutes to obtain a film thickness of 100 nm. A liquid crystal alignment film was formed.
Next, through a polarizing plate, the coating film surface was irradiated with 50 mJ/cm ² of linearly polarized ultraviolet light having a wavelength of 313 nm and an irradiation intensity of 4.3 mW/cm ² from an angle inclined by 40° from the normal direction of the substrate. got the substrate. Linearly polarized ultraviolet light was prepared by passing ultraviolet light from a high-pressure mercury lamp through a band-pass filter with a wavelength of 313 nm and then passing it through a polarizing plate with a wavelength of 313 nm.
Two of the above substrates were prepared, and after scattering bead spacers of 4 μm on the liquid crystal alignment film of one of the substrates, a sealant (XN-1500T manufactured by Mitsui Chemicals, Inc.) was applied. Then, the other substrate was pasted 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 liquid crystal (MLC-3022, manufactured by Merck Co.) was injected into this empty cell by a vacuum injection method to obtain a liquid crystal display device.

<Evaluation>
(Liquid crystal orientation)
After the liquid crystal display device obtained above was subjected to an isotropic phase treatment at 120° C. for 1 hour, the cell was observed with a polarizing microscope. The case where there was no orientation defect such as light leakage or domain generation, or the case where uniform driving of the liquid crystal was obtained when a voltage was applied to the liquid crystal cell was evaluated as good. Table 2 shows the evaluation results.

(pretilt angle)
The pretilt angle of the liquid crystal cell of the liquid crystal display element produced above was measured by the Mueller matrix method using AxoScan manufactured by Axometrics. Table 2 shows the evaluation results.

(Evaluation of pretilt angle change)
A DC voltage of 15 V was applied to the liquid crystal display element whose pretilt angle was measured above, and the pretilt angle was measured again after 24 hours. A change in pretilt angle (Δ _pretilt ) was obtained from the pretilt angle before and after applying the DC voltage. Table 2 shows the evaluation results.

As can be seen from the results in Table 2, MA-1, MA-2, GMA, and a liquid crystal obtained from a liquid crystal aligning agent obtained by blending a polymethacrylate solution obtained by copolymerizing MAA, or a polymethacrylate solution and a polyamic acid or polyimide solution. The alignment film had higher tilt stability than the liquid crystal alignment film of the comparative example. Specifically, Example 1 and Comparative Examples 1 and 2, Example 2 and Comparative Example 3, and Example 3 and Comparative Example 4 are compared.

The liquid crystal aligning agent of the present invention and the liquid crystal display element using the liquid crystal aligning film obtained therefrom can be suitably used for liquid crystal display elements that require durability such as in-vehicle use.

Claims

A liquid crystal aligning agent containing the following component (A) and a solvent:
(A) component: a polymer having the following structures (A-1) to (A-4);
(A-1) a structure having at least one functional group selected from the group consisting of a carboxy group, an amino group and a hydroxy group;
(A-2) the following formula (pa-1) (wherein A is optionally a group selected from fluorine, chlorine, cyano, or an alkoxy group having 1 to 5 carbon atoms, linear or branched pyrimidine-2,5-diyl, pyridine-2,5-diyl, substituted with an alkyl residue of optionally substituted with one cyano group or one or more halogen atoms, thiophene-2,5-diyl, furan-2,5-diyl, 1,4- or 2,6-naphthylene or phenylene, R 1 is a single bond, an oxygen atom, -COO- or -OCO-, R 2 is a divalent aromatic group, divalent alicyclic group, divalent heterocyclic group or divalent condensed cyclic 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 including a linear or branched alkyl group or alicyclic group having 1 to 40 carbon atoms, D is an oxygen atom, sulfur atom or —NR d — (here, R d represents a hydrogen atom or alkyl having 1 to 3 carbon atoms), and X and Y each independently represent a hydrogen atom, a fluorine atom, a chlorine atom, a cyano group or represents an alkyl group having 1 to 3 carbon atoms, a is an integer of 0 to 3, and * represents a bond When a is 2 or more, a plurality of R 1 and R 2 are each independently has a definition.);
(A-3) from the group consisting of an oxetanyl group, an oxiranyl group, a group represented by the following formula (3), a group represented by the following formula (4), a group represented by the following formula (5), and a thiirane group a structure having at least one selected functional group;
(A-4) the following formula (pa-2) (wherein L 1 , L 2 and L 3 are each independently a single bond, -O-, -CH 2 -, -COO-, -OCO-, represents -CONH- or -NH-CO-;
T is a single bond or an alkylene group having 1 to 12 carbon atoms, and the hydrogen atoms bonded thereto may be replaced with a halogen group;
when T is a single bond then L2 also represents a single bond;
Y 1 is a divalent benzene ring;
P 1 and Q 1 are each independently a group selected from the group consisting of a benzene ring and an alicyclic hydrocarbon ring having 5 to 8 carbon atoms;
R 11 is a hydrogen atom, —CN, a halogen group, an alkyl group having 1 to 5 carbon atoms, an (alkyl having 1 to 5 carbon atoms)carbonyl group, a cycloalkyl group having 3 to 7 carbon atoms or a cycloalkyl group having 1 to 5 carbon atoms. It is an alkyloxy group.
In Y 1 , P 1 and Q 1 , the hydrogen atoms bonded to the benzene ring are each independently —CN, a halogen group, an alkyl group having 1 to 5 carbon atoms, an (alkyl having 1 to 5 carbon atoms) carbonyl group, or a carbon may be substituted with an alkyloxy group of numbers 1 to 5;
X 1 represents a single bond, -O-, -COO- or -OCO-;
n1 is 0, 1 or 2;
when the number of X 1 is 2, X 1 may be the same or different;
When the number of Q 1 is 2, Q 1 may be the same or different;
A dashed line represents a bond with a polymerizable group. ).
(A-2) is represented by the following formula (b-1-m) (wherein M c represents a second polymerizable group, M d represents a single bond, a (r 2 +1)-valent heterocyclic ring, a group selected from (r 2 +1)-valent linear or branched hydrocarbon groups having 1 to 10 carbon atoms, (r 2 +1)-valent aromatic groups, and (r 2 +1)-valent alicyclic groups; and each group may be unsubstituted or one or more hydrogen atoms may be substituted by a fluorine atom, a chlorine atom, a cyano group, a methyl group or a methoxy group, and S b is a single bond, the number of carbon atoms 1 to 10 linear or branched alkylene group, divalent aromatic group or divalent alicyclic group, I b is a group represented by formula (pa-1), r 2 is , an integer satisfying 1≦r 2 ≦3).
—S b —I b in the formula (b-1-m) is represented by the following formula (pa-1-a) (wherein S b has the same definition as S b in formula (b-1-m) and 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, and R 1 is a single bond, an oxygen atom, —COO— or —OCO—, R2 is a divalent aromatic group, divalent alicyclic group, or divalent heterocyclic group, and R3 is a single a bond, an oxygen atom, —COO— or —OCO—, and R 4 is a monovalent organic group having 3 to 40 carbon atoms, including a linear or branched alkyl group or alicyclic group having 1 to 40 carbon atoms and 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, a is an integer of 0 to 3, and b is an integer of 0 to 4 (When a is 2 or more, each of the plurality of R 1 and R 2 independently has the above definition.When b is 2 or more, the plurality of R 5 each independently has the above definition.) The liquid crystal aligning agent according to claim 2, which is a site having photoalignability represented by.
(A-4) is represented by the following formula (d-1-m) (wherein M f represents a fourth polymerizable group, M g represents a single bond, an (r 3 +1)-valent heterocyclic ring, a group selected from (r 3 +1)-valent linear or branched hydrocarbon groups having 1 to 10 carbon atoms, (r 3 +1)-valent aromatic groups, and (r 3 +1)-valent alicyclic groups; and each group may be unsubstituted or one or more hydrogen atoms may be substituted by a fluorine atom, a chlorine atom, a cyano group, a methyl group or a methoxy group, and S d is a single bond, the number of carbon atoms 1 to 10 linear or branched alkylene group, divalent aromatic group or divalent alicyclic group, I d is a group represented by formula (pa-2), r 3 is , an integer satisfying 1 ≤ r 3 ≤ 3. When r 3 is 2 or more, a plurality of S d and I d each independently have the above definition. 1. The liquid crystal aligning agent according to 1.
—S d —I d in (d-1-m) is represented by the following formula (pa-2-a) (wherein S d , L 1 , and R 11 have the same definitions as above); 5. The liquid crystal aligning agent according to claim 4, which is a site having photo-orientation.
The (A-1) is at least one portion of the following formula (a-1-m) (wherein I a1 is a carboxy group and the following formula (a2) (wherein * represents a bond) a monovalent organic group selected from a group having a structure or a primary amino group, r 1 is 1 or 2, Sa represents a single bond or a divalent linking group, M a represents a 1, provided that the above formula (a2) represents a group other than a primary amino group, and when r 1 is 2, a plurality of S a and I a1 each independently have the above definition. The liquid crystal aligning agent according to claim 1, which is derived from a monomer represented by ).
(A-3) is represented by the following formula (c-1-m) (wherein I c is an oxetanyl group, an oxiranyl group, a group represented by the above formula (3), or a group represented by the above formula (4) is a monovalent organic group selected from the group consisting of a group represented by the above formula (5) and a thiirane group, Sc represents a single bond or a divalent linking group, and Me represents a 3. The liquid crystal aligning agent according to claim 1, characterized by being derived from a monomer represented by .
Containing 20 to 94 mol% of the monomer derived from the site (A-1) with respect to the entire polymer of the component (A), and 5 monomers derived from the site (A-2) Containing at a rate of ~50 mol%, containing a monomer derived from the site (A-3) at a rate of 1 to 30 mol%, and containing a monomer derived from the site (A-4) at a rate of 1 to 20 mol% 2. The liquid crystal aligning agent according to claim 1, wherein the liquid crystal aligning agent is obtained from a monomer component.
The liquid crystal aligning agent according to any one of claims 1 to 8, wherein the weight average molecular weight of the polymer of component (A) is 2,000 to 1,000,000.
A liquid crystal alignment film formed using the liquid crystal alignment agent according to any one of claims 1 to 9.
A step of applying the liquid crystal aligning agent according to any one of claims 1 to 10 on a substrate to form a coating film, and the coating film is not in contact with the liquid crystal layer or with the liquid crystal layer A method for producing a liquid crystal alignment film, comprising a step of irradiating the coating film with light in a contact state.
A liquid crystal display element comprising the liquid crystal alignment film according to claim 10.