WO2024058169A1

WO2024058169A1 - Weak-anchoring liquid crystal aligning agent and liquid crystal display element

Info

Publication number: WO2024058169A1
Application number: PCT/JP2023/033185
Authority: WO
Inventors: 一世三宅
Original assignee: 日産化学株式会社
Priority date: 2022-09-13
Filing date: 2023-09-12
Publication date: 2024-03-21

Abstract

Provided is a weak-anchoring liquid crystal aligning agent which is used for the formation of a liquid crystal alignment film in a liquid crystal cell having a liquid crystal and the liquid crystal alignment film, and comprises a polymer (P) produced by a compound that has a polymerizable group having a polymerizable unsaturated hydrocarbon group and a compound serving as a solvent and represented by formula (1). (In formula (S1), Q¹ and Q² each independently represent an alkyl group having 1 to 4 carbon atoms; and Q³ represents a linear, branched or cyclic alkyl group having 1 to 8 carbon atoms, an alkoxyalkyl group having 2 to 8 carbon atoms, an alkylcarbonylalkyl group having 4 to 8 carbon atoms, or a hydrogen atom; in which the total number of carbon atoms in Q¹, Q² and Q³ is 4 or more.)

Description

Weak anchoring liquid crystal alignment agent and liquid crystal display element

The present invention makes it possible to produce an organic film that exhibits weak anchoring properties (weak anchoring film) using a method that is inexpensive and does not involve complicated processes, and enables even higher brightness and lower voltage driving. The present invention relates to a liquid crystal display element for realizing the above, and a weakly anchoring liquid crystal aligning agent and a copolymer that can be used therefor.

In recent years, liquid crystal display elements have been widely used in displays for mobile phones, computers, televisions, and the like. Liquid crystal display elements have characteristics such as being thin, lightweight, and low power consumption, and are expected to be applied to further content such as VR (Virtual Reality) and ultra-high-definition displays in the future. Various display methods have been proposed for liquid crystal displays, including the TN (Twisted Nematic) method, the IPS (In-Plane Switching) method, and the VA (Vertical Alignment) method. A film (liquid crystal alignment film) that induces a desired alignment state is used.

In particular, for products equipped with touch panels such as tablet PCs, smartphones, and smart TVs, the IPS method is preferred because the display is less distorted even when touched, and in recent years FFS (Fringe Field Switching ) liquid crystal display elements using the method and liquid crystal alignment technology using the optical alignment method are used.

However, the FFS method has problems in that the manufacturing cost of the substrate is higher than that in the IPS method, and a unique display defect called Vcom shift occurs. Furthermore, compared to the rubbing alignment method, the photo-alignment method has the advantage of being easier to adapt to device enlargement and greatly improving display characteristics, but there are some theoretical issues (when using photodegradable materials, Display defects, and if the photoisomerization type is used, there may be burn-in due to insufficient alignment power, etc.). In order to solve these problems, liquid crystal display element manufacturers and liquid crystal alignment film manufacturers are currently making various efforts.

In recent years, at the contact interface between the liquid crystal and the base material in a liquid crystal cell, a compatible interface (completely wet liquid-liquid crystal interface) is formed between the polymer and the liquid crystal, which has no alignment regulating force in the in-plane direction. It has been discovered that it is possible to create a "zero-plane anchoring" state, and a liquid crystal switching device that has no switching threshold and has orientation memory has been reported (see Patent Document 1).

A weak anchoring IPS method that applies weak anchoring technology has been proposed. This can improve the contrast ratio and realize significantly lower voltage driving than the conventional IPS method (see Patent Document 2).

The weak anchoring IPS method uses a liquid crystal alignment film that has strong anchoring energy on one substrate, and a process that does not have anchoring energy on the other substrate (which is equipped with an electrode that generates a transverse electric field). It is made using organic thin films.

In recent years, a weak anchoring IPS method using a method of directly providing a thick polymer brush on a substrate has been proposed (see Patent Document 3).

In addition, as another method, a weak anchoring IPS method has been proposed, which uses a liquid crystal alignment film that can generate photoradicals and a compound that can undergo radical polymerization, and generates weak anchoring by irradiating UV in the liquid crystal and causing a radical reaction. (See Patent Document 4). With this technology, in addition to improving contrast ratio and significantly lower voltage drive using a method that can be mass-produced, we have achieved faster response and reduced burn-in.

Patent No. 2006-84536 Patent No. 4053530 Japanese Patent Application Publication No. 2013-231757 International Publication No. 2019/004433 pamphlet

The method of directly providing a dense polymer brush on a substrate (Patent Document 3) requires a surface treatment step to provide reaction points on the substrate and a step of growing the polymer from the reaction points on the substrate surface, which complicates the process and requires high altitude. This method is technically difficult because it requires strict deoxidation conditions and the environment must be strictly controlled, making it impractical from the perspective of mass production. Therefore, a method has been proposed in which a weakly anchored IPS display element is obtained by applying a bottlebrush polymer having an anchoring site onto a substrate.However, when manufacturing a bottlebrush polymer, a macromonomer having a polymerization initiation site is used. However, in addition, since both are produced using living radical polymerization, there is a problem in that it is difficult to supply them in large quantities. In addition, bottle brush polymers have poor solvent selectivity and low solubility in commonly used N-methyl-2-pyrrolidone (NMP) and γ-butyrolactone (GBL). Because of its structure, it has poor sealing and adhesion to substrates, so it is necessary to devise a method that can solve these problems.

The present inventors have proposed a block copolymer having a block segment that is insoluble in liquid crystal or becomes insolubilized by heating and a block segment that is compatible with liquid crystal as a material exhibiting weak anchoring properties (Japanese Patent Application No. 2021-96448 and (See WO2022/260048). However, the bottle brush polymer and the block copolymer are generally made of NMP (N-methyl-2-pyrrolidone) or GBL (γ-butyrolactone), which are used in general liquid crystal alignment agents (agents used to form liquid crystal alignment films). The problem is that although they show solubility, they tend to precipitate or gel during storage, and when these solvents are used for coating, pinholes and unevenness tend to occur.
Furthermore, the block segments of the block copolymer and the like that are compatible with the liquid crystal have no polarity and low viscosity due to their structure. Therefore, the coating uniformity of the liquid crystal alignment film, especially the coating properties at the edges, tends to deteriorate, and the edges of the liquid crystal alignment film are likely to be not straight or swollen.
Due to these factors, there is a problem in that it is difficult to form a high-quality coating film using a flexographic printing method, an inkjet method, or the like used in the liquid crystal aligning agent coating process. Therefore, even if good characteristics are obtained with a weakly anchored IPS display element, a problem arises in that panels for televisions, smartphones, etc. cannot be manufactured in the actual manufacturing process.

If such technical issues can be resolved, it will be a huge cost advantage for panel manufacturers, and it is also thought to have benefits such as reducing battery consumption and improving image quality.

The present invention was made to solve the above-mentioned problems, and provides a weakly anchoring liquid crystal aligning agent that can form a coating film of higher quality than conventional methods, and a weakly anchoring IPS display element using the same. , even in narrow cell gaps, stable low-voltage drive without the occurrence of pre-tilt angles and high-speed response when the voltage is turned off can be achieved at the same time.In addition, burn-in can be reduced, and high backlight transmittance and low voltage can be achieved in low-temperature environments. It is an object of the present invention to provide a transverse electric field liquid crystal display element that can achieve both driving performance.

In order to solve the above problems, the present inventors conducted intensive studies, and as a result found that the above problems could be solved, and completed the present invention having the following gist.

That is, the present invention includes the following.
[1] Used for forming the liquid crystal alignment film of a liquid crystal cell having a liquid crystal and a liquid crystal alignment film,
A weakly anchoring liquid crystal aligning agent containing a polymer (P) obtained from a compound having a polymerizable group having a polymerizable unsaturated hydrocarbon group, and a compound represented by the following formula (1) as a solvent.

(In formula (S1), Q ¹ and Q ² each independently represent an alkyl group having 1 to 4 carbon atoms, and Q ³ represents a linear, branched, or cyclic alkyl group having 1 to 8 carbon atoms; represents an alkoxyalkyl group having 2 to 8 carbon atoms, an alkylcarbonylalkyl group having 4 to 8 carbon atoms, or a hydrogen atom, and the total number of carbon atoms of Q ¹ , Q ² and Q ³ is 4 or more.)
[2] The compound represented by the formula (1) is N,N-diethylacetamide, N,N-diethylformamide, N,N-dibutylformamide, N,N-dipropylacetamide, N,N-dimethylpropion Amide, N,N-diethylpropionamide, 3-methoxy-N,N-dimethylpropanamide, 2-methoxy-N,N-diethylacetamide, 3-methoxy-N,N-diethylpropanamide, 4-oxo-N , N-diethylpentanamide, and N,N-diethylcyclohexanecarboxamide, the weakly anchoring liquid crystal aligning agent according to [1].
[3] The content of the compound represented by the formula (1) is 10 to 90% by mass with respect to the total amount of the solvent component contained in the weakly anchoring liquid crystal aligning agent [1] to [2] ] The weak anchoring liquid crystal aligning agent according to any one of the above.
[4] The weak polymer according to any one of [1] to [3], wherein the polymer (P) is at least one selected from the group consisting of the following polymers (α) and polymers (β). Anchoring liquid crystal alignment agent.
Polymer (α): A block copolymer having a block segment (A) that is compatible with the liquid crystal and a block segment (B) that is not compatible with the liquid crystal or becomes insolubilized in the liquid crystal upon firing.
Polymer (β): A graft copolymer having a trunk polymer and a branch polymer bonded to the trunk polymer as a side chain of the trunk polymer, and the branch polymer is compatible with the liquid crystal and the trunk polymer is not compatible with the liquid crystal or becomes insoluble in the liquid crystal upon firing.
[5] The block segment (A) in the polymer (α) and the branch polymer in the polymer (β) are a compound represented by the following formula (2), a compound represented by the following formula (3), Containing as a constituent component at least one selected from the group consisting of a compound represented by the following formula (4) and a compound represented by the following formula (5),
The block segment (B) in the polymer (α) and the backbone polymer in the polymer (β) contain a compound represented by the following formula (6) as a constituent component,
Weak anchoring liquid crystal aligning agent according to [4].

(In formula (2), M represents a polymerizable group having a polymerizable unsaturated hydrocarbon group, and X represents a single bond, ether bond, ester bond, amide bond, urethane bond, urea bond, or thioether bond. , R ₁ represents an alkyl group having 1 to 20 carbon atoms which may have a bonding group inserted therein, and n is an integer of 1 to 2. When n is 2, the two X and R ₁ are each the same. (It may be different or it may be different.)

(In formula (3), M represents a polymerizable group having a polymerizable unsaturated hydrocarbon group, and S represents a single bond or a saturated hydrocarbon group having 1 to 6 carbon atoms which may have a bonding group inserted therein. , T represents an organic group represented by the following formula (3-T), and n is an integer of 1 to 2. When n is 2, the two Ts may be the same or different. (However, when n is 2, S represents a saturated hydrocarbon group having 1 to 6 carbon atoms that may have a bonding group inserted.)

(In formula (3-T), * indicates a bonding site. X is a single bond, ether bond, ester bond, amide bond, urethane bond, urea bond, thioether bond, -Si(R ₁ )(R ₂ )- (R ₁ and R ₂ each independently represent an alkyl group bonded to Si.), -Si(R ₃ )(R ₄ )-O-(R ₃ and R ₄ each independently bond to Si. represents an alkyl group), and -N(R ₅ )-(R ₅ represents a hydrogen atom or an alkyl group bonded to N), and Cy is a 6- to 20-membered non-ring group. (Represents an aromatic cyclic group.)

(In formula (4), M represents a polymerizable group having a polymerizable unsaturated hydrocarbon group, R ₁ represents an aliphatic hydrocarbon group having a linear or branched structure having 1 to 10 carbon atoms, and 3 Each of the three X's independently represents a hydrogen atom or the following formula (4-X).However, at least one of the three X's represents the formula (4-X).)

(In formula (4-X), Y represents a single bond, -O-, -S-, or -N(R)-(R represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms bonded to N. ), and * indicates a bonding site. _{R 2} , R ₃ , and R ₄ each independently represent an alkyl group having 1 to 6 carbon atoms or an aromatic hydrocarbon group that may have a substituent. )

(In formula (5), M represents a polymerizable group having a polymerizable unsaturated hydrocarbon group, and R ₁ to R ₃ are each independently a single bond or the number of carbon atoms into which a bonding group may be inserted. represents an alkylene group of 1 to 6, Ar represents an aromatic hydrocarbon group that may have a substituent, and X ₁ and X ₂ are each independently a hydrogen atom, or R ₁ X ₁ and R ₂ X ₂ and the carbon atoms bonded to R ₁ X ₁ and R ₂ X ₂ may form a ring together. The total number of carbon atoms in R ₁ X ₁ , R ₂ X ₂ and R ₃ is 1 or more.)

(In formula (6), M represents a polymerizable group having a polymerizable unsaturated hydrocarbon group, and n is an integer of 1 to 2. Z represents a group represented by the following formula (6-Z). (If n is 2, the two Zs may be the same or different.)

(In formula (6-Z), L is a trialkoxysilyl group, an isocyanate group, a blocked isocyanate group, an epoxy group, an oxetane group, a vinyl group, an allyl group, an oxazoline group, an amino group, a protected amino group, an aniline group, a protected aniline group) group, hydroxy group, protected hydroxy group, phenol group, protected phenol group, thiol group, protected thiol group, thiophenol group, protected thiophenol group, aldehyde group, carboxy group, maleimide group, N-hydroxysuccinimide ester group, bonding group Aromatic hydrocarbon group having 5 to 18 carbon atoms which may have a bonding group inserted therein, an aromatic heterocyclic group having 5 to 18 carbon atoms which may have a bonding group inserted therein, a cinnamic acid group, a cinnamic acid aromatic ester group , a cinnamic acid alkyl ester group, a cinnamyl group, a phenylbenzoate group, an azobenzene group, an N-benzylideneaniline group, a stilbene group, and a tolan group. J is a single bond or has 1 to 1 carbon atoms. 6 represents an aliphatic hydrocarbon group.When K is bonded to an aromatic hydrocarbon group, it represents a linking group selected from a single bond, an ether bond, an ester bond, an amide bond, a urea bond, a urethane bond, and a thioether bond. In other cases, it indicates a single bond. * represents a binding site. m is an integer from 1 to 3. When m is 2 or 3, multiple K and L may be the same. (However, if J is a single bond, m is 1.)
[6] The weakly anchoring liquid crystal aligning agent according to [5], wherein the branch polymer in the polymer (β) is derived from a macromonomer represented by the following formula (7).

(In formula (7), P represents a polymerizable group having a polymerizable unsaturated hydrocarbon group, and Q represents a polymerizable monomer containing at least one of the compounds represented by formulas (2) to (5) above. (n is an integer of 1 to 2. When n is 2, the two Qs may be the same or different.)
[7] M in the formula (2) is any of the structures represented below,
M in the formula (3) is any of the structures represented below,
M in the formula (4) is any of the structures represented below,
M in the formula (5) is any of the structures represented below,
M in the formula (6) is any of the structures represented below,
Weak anchoring liquid crystal aligning agent according to [5].

(In the formula, R ₁ and R ₂ each independently represent a hydrogen atom or a linear or branched alkyl group having 1 to 12 carbon atoms, and X, Y, and Z each independently represent an oxygen atom or a sulfur atom. *, * ¹ and * ² represent bonding sites, and either one of * ¹ and * ² may be replaced with a hydrogen atom or a straight chain or branched alkyl group having 1 to 12 carbon atoms.)
[8] The polymer (α) and the polymer (β) contain at least one constituent selected from the group consisting of compounds represented by the following formulas (B-1) to (B-17). The weakly anchoring liquid crystal aligning agent according to any one of [4] to [7], comprising:

(In formulas (B-1) to (B-17), Me represents a methyl group, and Et represents an ethyl group.)
[9] A liquid crystal display element obtained using the weakly anchoring liquid crystal aligning agent according to any one of [1] to [8].
[10] The liquid crystal display element according to [9], which is a lateral electric field liquid crystal display element.
[11] A method for manufacturing a liquid crystal display element, comprising applying and baking the weakly anchoring liquid crystal aligning agent according to any one of [1] to [8].
[12] The method for manufacturing a liquid crystal display element according to [11], wherein the liquid crystal display element is a horizontal field liquid crystal display element.

According to the present invention, a stable weak anchoring alignment film can be produced using an extremely simple method compared to the conventional technology, thereby reducing the process load and yield rate required for producing weak anchoring horizontal electric field liquid crystal display elements in actual industrialization. It is possible to improve the By using the material and method of the present invention, the stability of the composition solution is superior to that of the conventional technology, the applicability by flexographic printing is greatly improved, and the material can stably exhibit excellent weak anchoring IPS properties. A transverse electric field liquid crystal display element can be provided.

1 is a schematic cross-sectional view showing an example of a horizontal electric field liquid crystal display element of the present invention. FIG. 3 is a schematic cross-sectional view showing another example of the horizontal electric field liquid crystal display element of the present invention.

(weak anchoring)
In the present invention, "weak anchoring" refers to having a force that regulates the alignment of liquid crystal molecules in the azimuthal or polar direction with respect to the substrate, but with anchoring strength (i.e., maintaining the position of the liquid crystal molecules). Alternatively, even if the orientation of liquid crystal molecules changes, there is no interfacial elastic energy to restore the original state, or even if there is, it is weaker than the intermolecular force between liquid crystals, and in the weak anchoring of the present invention. refers to the case where the azimuthal anchoring strength (A ₂ ) is smaller than 10 ⁻⁵ [J/m ² ]. As described in JP-A No. 2013-231757, a polymer capable of forming a completely wet state with the liquid crystal is provided at the interface of the base material, and when the liquid crystal comes into contact with the polymer, a polymer-liquid crystal mixed layer is formed and weak anchoring is achieved. The condition is known to occur.

(Weak anchoring alignment film)
In the present invention, the term "weak anchoring alignment film" refers to a film that forms a weak anchoring state upon contact with liquid crystal, and is not limited to solid films, but also includes liquid films that cover solid surfaces.

(Strong anchoring, strong anchoring alignment film)
In the present invention, "strong anchoring" refers to the ability to regulate the alignment of liquid crystal molecules in a uniaxial alignment and maintain the alignment of the liquid crystal even when energy is applied from the outside, or the ability to maintain the alignment of the liquid crystal even if the alignment of the liquid crystal molecules changes. In the strong anchoring of the present invention, it refers to the case where the azimuthal anchoring strength (A ₂ ) is greater than 10 ⁻⁴ [J/m ² ]. . Furthermore, the term "strongly anchoring alignment film" refers to a film that forms a strong anchoring state when it comes into contact with liquid crystal, and is not limited to solid films, but also includes liquid films that cover solid surfaces.

(Weak anchoring liquid crystal display element)
A weak anchoring liquid crystal display element can be produced by applying the weak anchoring alignment film and the strong anchoring alignment film defined above to a substrate with electrodes, respectively, and pasting them together in a pair. In weak anchoring liquid crystal display elements, the azimuthal anchoring strength of one liquid crystal alignment film is extremely small, so a weak electric field or external field energy can induce alignment changes in the liquid crystal, and liquid crystal molecules in areas that normally do not move can also be aligned. This makes it possible to drive liquid crystal molecules on electrodes with weak electric field strength, especially in display elements using comb-shaped electrodes such as IPS and FFS. Compared to a liquid crystal display element in which both of the films are composed of strong anchoring alignment films, higher transmittance and lower driving voltage can be achieved.

The azimuthal anchoring strength is an index representing the strength of interfacial elastic energy between liquid crystal molecules and a liquid crystal alignment film in the azimuthal direction. As a method for calculating the azimuthal anchoring strength, a torque balance method, a strong electric field method, a geometry method (external field application method), a Frederiks transfer method, etc. are used.

(Weak anchoring liquid crystal alignment agent)
The weakly anchoring liquid crystal aligning agent of the present invention is used for forming a liquid crystal aligning film of a liquid crystal cell having a liquid crystal and a liquid crystal aligning film.
The weak anchoring liquid crystal aligning agent comprises a polymer (P) obtained from a compound having a polymerizable group having a polymerizable unsaturated hydrocarbon group, and a compound represented by the following formula (1) as a solvent (hereinafter referred to as " (sometimes referred to as "specific solvents").

(In formula (1), Q ¹ and Q ² each independently represent an alkyl group having 1 to 4 carbon atoms, and Q ³ represents a linear, branched, or cyclic alkyl group having 1 to 8 carbon atoms, represents an alkoxyalkyl group having 2 to 8 carbon atoms, an alkylcarbonylalkyl group having 4 to 8 carbon atoms, or a hydrogen atom, and the total number of carbon atoms in Q ¹ , Q ² and Q ³ is 4 or more.)

The polymer (P) is preferably at least one selected from the group consisting of polymers (α) and polymers (β).

The liquid crystal aligning agent of the present invention includes a solid component consisting of a block copolymer [polymer (α)] and/or a graft copolymer [polymer (β)] described below as the polymer (P), and A preferred embodiment includes a specific solvent as a solvent for dissolving.
Block copolymers and graft copolymers are materials for weak anchoring films, and the specific solvent used as a solvent has very good solubility for the block copolymers and graft copolymers, and Since it shows good applicability in coating and flexographic printing, it is possible to obtain a weakly anchored liquid crystal alignment film of very high quality as a result.

The block copolymers and graft copolymers used in the present invention have poor solubility in conventionally used solvents such as NMP and GBL, and although they exhibit solubility, they precipitate or gel during storage. However, when these solvents are used for coating, pinholes and unevenness are likely to occur. Further, block copolymers and graft copolymers have block segments that are compatible with liquid crystals and have low polarity and low viscosity due to their structures. Therefore, the coating uniformity of the liquid crystal alignment film obtained by applying the liquid crystal alignment agent, especially the coating properties at the edges, tends to deteriorate, and the edges of the liquid crystal alignment film are not straight or are raised. condition becomes more likely.
The specific solvent is also characterized by its high viscosity due to hydrogen bonds derived from amide bonds.
It has been found that these problems can be solved by using a specific solvent in the weakly anchoring liquid crystal aligning agent of the present invention, and that it is possible to increase the viscosity and improve the storage stability, coatability, and printability of the liquid crystal aligning agent. Do you get it. Another feature is that it causes less damage to APR printing plates used in flexo printing.

Examples of the alkyl group having 1 to 4 carbon atoms in Q ¹ and Q ² in formula (1) include methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, and tert-butyl group. Examples include. Among these, methyl group and ethyl group are preferred.
Examples of the linear, branched, or cyclic alkyl group having 1 to 8 carbon atoms in Q ³ in formula (1) include methyl group, ethyl group, n-propyl group, i-propyl group, n- Examples include butyl group, tert-butyl group, and cyclohexyl group. Among these, methyl group and ethyl group are preferred.
Examples of the alkoxyalkyl group having 2 to 8 carbon atoms in Q ³ in formula (1) include C1 to C4 alkoxyC2 to C4 alkyl groups. Examples of the alkoxyalkyl group having 3 to 8 carbon atoms include 2-methoxyethyl group, 2-butoxyethyl group, 1-methoxymethyl group, 2-methoxyethyl group, and 3-methoxypropyl group.
Examples of the alkylcarbonylalkyl group having 4 to 8 carbon atoms in Q ³ in formula (1) include 4-oxopentyl group, 3-oxopentyl group, and 5-oxohexyl group.

Preferred examples of the specific solvent include N,N-diethylacetamide, N,N-diethylformamide, N,N-dibutylformamide, N,N-dipropylacetamide, N,N-dimethylpropionamide, N,N-diethyl Examples include propionamide, 3-methoxy-N,N-dimethylpropanamide, and the like.
Particularly preferred specific solvents include N,N-diethylacetamide, N,N-diethylformamide, 3-methoxy-N,N-dimethylpropanamide, 2-methoxy-N,N-diethylacetamide, 3-methoxy-N,N -diethylpropanamide, 4-oxo-N,N-diethylpentanamide, N,N-diethylcyclohexanecarboxamide and the like.

Although the introduction ratio of the specific solvent is not particularly limited with respect to the total amount of solvent components contained in the liquid crystal aligning agent, it is preferably 10 to 90% by mass, more preferably 30 to 80% by mass.

Among the above-mentioned preferred specific solvents, when N,N-diethylacetamide, N,N-diethylformamide, N,N-dimethylpropionamide, and N,N-diethylpropionamide are used as the main solvent, they are slightly less expensive than conventional solvents. It has a low boiling point, and there is a risk that coating properties will deteriorate during printing and other applications where there is a waiting time between coating and drying. Therefore, it is preferable to use a specific high-boiling point solvent with a relatively high boiling point among the specific solvents represented by (S) above.

The specific high-boiling point solvent is a solvent with a relatively high boiling point among the specific solvents represented by formula (S1), and refers to a solvent with a boiling point exceeding 200°C. Preferred examples of the specific high boiling point solvent include N,N-dibutylformamide, 4-oxo-N,N-diethylpentanamide, N,N-diethylcyclohexanecarboxamide, and the like.
The boiling point here refers to the boiling point at 1 atmosphere.

The ratio of the specific high boiling point solvent to the total amount of solvent components contained in the liquid crystal aligning agent is not particularly limited, but is preferably 5 to 50% by mass, more preferably 10 to 30% by mass.

(Polymer (P))
The polymer (P) is a polymer obtained from a compound having a polymerizable group having a polymerizable unsaturated hydrocarbon group. In other words, the polymer (P) is a polymer obtained by polymerizing the polymerizable group of a compound having a polymerizable group having a polymerizable unsaturated hydrocarbon group.

The polymer (P) is preferably at least one selected from the group consisting of the following polymers (α) and polymers (β).
Polymer (α): A block copolymer having a block segment (A) that is compatible with liquid crystal and a block segment (B) that is not compatible with liquid crystal or becomes insolubilized in liquid crystal upon firing.
Polymer (β): A graft copolymer having a trunk polymer and a branch polymer bonded to the trunk polymer as a side chain of the trunk polymer.The branch polymer is compatible with the liquid crystal, and the trunk polymer is compatible with the liquid crystal. A graft copolymer that does not dissolve or becomes insoluble in liquid crystals upon firing.

(Block copolymer [polymer (α)])
One embodiment of the "copolymer" in the present invention is a copolymer contained in a weakly anchoring liquid crystal aligning agent.

The block copolymer [polymer (α)] has a block segment (A) that is compatible with the liquid crystal and a block segment (B) that is not compatible with the liquid crystal or becomes insolubilized in the liquid crystal upon firing. The block segment (A) consists of a polymer that is compatible with the liquid crystal even when the copolymer is fired.

Block segment (A) is a compound represented by the following formula (2), a compound represented by the following formula (3), a compound represented by the following formula (4), and a compound represented by the following formula (5). It is preferable that at least one kind selected from the group consisting of compounds is included as a constituent component.

It is preferable that the block segment (B) contains a compound represented by the following formula (6) as a constituent component.

The block copolymer may have three or more types of block segments.

The block copolymer is preferably a copolymer in which the main chain extends linearly without branching.
In the present invention, by using block segments compatible with liquid crystal as block segments of the block copolymer contained in one embodiment of the liquid crystal aligning agent, a weak anchoring film can be produced more easily than conventional methods. It is possible.

The present applicant has proposed a radically polymerizable compound contained in a liquid crystal composition that can stably produce a weakly anchoring horizontal electric field liquid crystal display element without generating a pretilt angle, and which is a radical polymerizable compound that contributes to the occurrence of weak anchoring. We have discovered and applied for a compound represented by the following formula (2), a compound represented by the formula (3), a compound represented by the formula (4), and a compound represented by the formula (5) as chemical compounds. (Patent application 2020-134149, Patent application 2020-163212, Patent application 2021-041196, WO2022/030602, PCT/JP2021/35557 (WO2022/071286), WO2019/004433. The contents of the applications and published publications of , are incorporated herein to the same extent as if expressly set forth in their entirety.)

In addition, the applicant has discovered that the weak anchoring liquid crystal aligning agent containing the polymer (α) can produce a weak anchoring film more easily and stably than conventional methods, and that it is also effective in narrowing the cell gap. A transverse electric field that can simultaneously achieve stable low-voltage driving and high-speed response when the voltage is OFF without generating a pre-tilt angle, reduce burn-in, and achieve both high backlight transmittance and low-voltage driving in low-temperature environments. We have found and filed an application to provide a liquid crystal display element (Japanese Patent Application No. 2021-96448 and PCT/JP2022/22993 (WO2022/260048). By being cited here, the entire content of this application is (incorporated herein to the same extent as if expressly set forth).

(In formula (2), M represents a polymerizable group having a polymerizable unsaturated hydrocarbon group, X represents a single bond, an ether bond, an ester bond, an amide bond, a urethane bond, a urea bond, or a thioether bond, _R1 represents an alkyl group having 1 to 20 carbon atoms which may have a bonding group inserted therein, and n is an integer of 1 to 2. When n is 2, the two X's and _R1 's may be the same or different.)
Examples of the linking group in the alkyl group having 1 to 20 carbon atoms into which a linking group may be inserted include an ether bond, an ester bond, an amide bond, a urethane bond, a urea bond, a thioether bond, -Si(R ₁₁ )(R ₁₂ )- (R ₁₁ and R ₁₂ each independently represent an alkyl group bonded to Si), -Si(R ₁₃ )(R ₁₄ )-O- (R ₁₃ and R ₁₄ each independently represent an alkyl group bonded to Si), and -N(R ₁₅ )- (R ₁₅ represents a hydrogen atom or an alkyl group bonded to N). Examples of the alkyl group in R ₁₁ to R ₁₅ include alkyl groups having 1 to 6 carbon atoms.

(In formula (3), M represents a polymerizable group having a polymerizable unsaturated hydrocarbon group, and S represents a single bond or a saturated hydrocarbon group having 1 to 6 carbon atoms which may have a bonding group inserted therein. , T represents an organic group represented by the following formula (3-T), and n is an integer of 1 to 2. When n is 2, the two Ts may be the same or different. (However, when n is 2, S represents a saturated hydrocarbon group having 1 to 6 carbon atoms which may have a bonding group inserted.)

The saturated hydrocarbon group in S in formula (3) refers to an n+1 valent group formed by removing n+1 hydrogen atoms from a saturated hydrocarbon (n is the same integer as n in formula (3)). be). When n is 1, the saturated hydrocarbon group is an alkylene group.
In S in formula (3), a saturated hydrocarbon group having 1 to 6 carbon atoms into which a bonding group is inserted is a saturated hydrocarbon group having a bonding group inserted between carbon atoms in a saturated hydrocarbon group having 2 to 6 carbon atoms. or an n+1-valent group in which a bonding group is inserted between a saturated hydrocarbon group having 1 to 6 carbon atoms and an atom bonded thereto (for example, a carbon atom).
Examples of the bonding group for S in formula (3) include a carbon-carbon unsaturated bond, an ether bond (-O-), an ester bond (-COO- or -OCO-), an amide bond (-CONH- or - Examples include NHCO-). Examples of carbon-carbon unsaturated bonds include carbon-carbon double bonds, but a saturated hydrocarbon group having 1 to 6 carbon atoms into which a carbon-carbon double bond is inserted has no It is preferable to have a carbon-carbon double bond inside.
When n is 1, examples of the alkylene group having 1 to 6 carbon atoms into which a bonding group may be inserted include alkylene groups having 1 to 6 carbon atoms, oxyalkylene groups having 1 to 6 carbon atoms, etc. .
The alkylene group having 1 to 6 carbon atoms may be a straight chain alkylene group, a branched alkylene group, or a cyclic alkylene group.

R ₁ and R ₂ of -Si(R ₁ )(R ₂ )- in X of formula (3-T) are each independently an alkyl group bonded to Si, for example, an alkyl group having 1 to 6 carbon atoms. It is the basis.
R ₃ and R ₄ of -Si(R ₃ )(R ₄ )-O- in X of formula (3-T) are each independently an alkyl group bonded to Si, for example, a carbon number of 1 to 6. is an alkyl group.
R ₅ of -N(R ₅ )- in X of formula (3-T) is a hydrogen atom or an alkyl group bonded to N. The alkyl group is, for example, an alkyl group having 1 to 6 carbon atoms.

In formula (3-T), Cy is a 6- to 20-membered non-aromatic cyclic group, preferably an 8- to 18-membered non-aromatic cyclic group. Note that Cy may be a 12- to 20-membered non-aromatic cyclic group. In formula (3-T), X is bonded to an atom constituting a ring in Cy.
Examples of atoms constituting the ring in the non-aromatic cyclic group include carbon atoms, oxygen atoms, nitrogen atoms, and silicon atoms.
The bond between the atoms constituting the ring may be a single bond, a double bond, or a triple bond, but a single bond is preferable.
Examples of the ring in the non-aromatic cyclic group include cyclic alkanes, cyclic ethers, and cyclic siloxanes. Examples of the cyclic ether include crown ether. For example, in 12-crown-4, the atoms constituting the ring are carbon atoms and oxygen atoms, and the number of members is 12.
The ring may be monocyclic or polycyclic. Examples of the number of rings in the polycycle include 2 to 4.
In a polycyclic ring, the following three ways are included, for example, in how the rings are bonded to each other.
・One-atom sharing: For example, spirocyclic compounds ・Two-atom sharing: When two rings share two atoms, such as in decalin. ・Bridging structure: When two rings share three atoms, such as in norbornane. Cases in which more than one atom is considered to be in common In the case of a polycyclic ring, the number of ring members is the number of atoms that make up the ring. For example, norbornane is a 7-membered ring.
A halogen atom or an alkyl group having 1 to 6 carbon atoms may be bonded to the atoms constituting the ring instead of a hydrogen atom. Examples of the halogen atom include a fluorine atom and a chlorine atom.

The aliphatic hydrocarbon group in R ₁ in formula (4) has 1 to 10 carbon atoms, may have 1 to 8 carbon atoms, may have 1 to 6 carbon atoms, or may have 1 to 6 carbon atoms. It may be 1 to 4.

The alkyl group having 1 to 6 carbon atoms in R ₂ , R ₃ , and R ₄ in formula (4-X) may be, for example, an alkyl group having 1 to 5 carbon atoms, or an alkyl group having 1 to 5 carbon atoms. 4 may be an alkyl group. These alkyl groups may have a linear structure or a branched structure.

The aromatic hydrocarbon groups represented by R ₂ , R ₃ , and R ₄ in formula (4-X) may be unsubstituted, or the hydrogen atoms may be substituted with a substituent.
Examples of the substituent of the aromatic hydrocarbon group which may have a substituent include a halogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, and a halogen having 1 to 4 carbon atoms. Examples include alkyl groups, halogenated alkoxy groups having 1 to 4 carbon atoms, and the like. The halogenation in the halogenated alkyl group and the halogenated alkoxy group may be complete halogenation or partial halogenation. Examples of the halogen atom include a fluorine atom and a chlorine atom.
Examples of the aromatic hydrocarbon group which may have a substituent include a phenyl group and a naphthyl group.
The number of substituents in the aromatic hydrocarbon group is not particularly limited.

In formula (4), formula (4-X) is one or more, and may be one, two, or three.
In formula (4), the three X's are each independent. Therefore, in formula (4), when there are two or more formulas (4-X), the two or more formulas (4-X) may have the same structure or different structures.

In formula (4-X), at least one of R ₂ , R ₃ and R ₄ may be an aromatic hydrocarbon group which may have a substituent. Therefore, in formula (4-X), one of R ₂ , R ₃ , and R ₄ may be an aromatic hydrocarbon group that may have a substituent, and R ₂ , R ₃ , and Two of R ₄ may be an aromatic hydrocarbon group which may have a substituent, or three of R ₂ , R ₃ and R ₄ may be an aromatic hydrocarbon group which may have a substituent. It may be a base.

In R ₁ to R ₃ in formula (5), an alkylene group having 1 to 6 carbon atoms into which a bonding group is inserted is an alkylene group having a bonding group inserted between carbon atoms in the alkylene group having 1 to 6 carbon atoms. or a divalent group in which a bonding group is inserted between an alkylene group having 1 to 6 carbon atoms and a carbon atom bonded thereto.
Examples of the bonding group include a carbon-carbon unsaturated bond, an ether bond (-O-), an ester bond (-COO- or -OCO-), and an amide bond (-CONH- or -NHCO-). Examples of unsaturated bonds include carbon-carbon double bonds, but alkylene groups with 1 to 6 carbon atoms into which a bonding group is inserted have a carbon-carbon double bond inside, not at the end. It is preferable to have a bond.
Examples of the alkylene group having 1 to 6 carbon atoms into which a bonding group may be inserted include alkylene groups having 1 to 6 carbon atoms, oxyalkylene groups having 1 to 6 carbon atoms, and the like. The oxygen atom in the oxyalkylene group having 1 to 6 carbon atoms is bonded to, for example, the carbon atom bonded to M, R ₁ , R ₂ , and R ₃ in formula (5).
The alkylene group having 1 to 6 carbon atoms may be a straight chain alkylene group, a branched alkylene group, or a cyclic alkylene group.

Examples of the aromatic hydrocarbon group which may have a substituent in X ₁ and X ₂ of formula (5) include a phenyl group, a naphthyl group, and the like which may have a substituent.
Examples of the substituent include a halogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a halogenated alkyl group having 1 to 4 carbon atoms, a halogenated alkoxy group having 1 to 4 carbon atoms, etc. can be mentioned. The halogenation in the halogenated alkyl group and the halogenated alkoxy group may be complete halogenation or partial halogenation. Examples of the halogen atom include a fluorine atom and a chlorine atom.

Examples of R ₁ in formula (5) include a single bond and an alkylene group having 1 to 6 carbon atoms. More specifically, the alkylene group having 1 to 6 carbon atoms includes a straight chain alkylene group having 1 to 6 carbon atoms.
Examples of R ₂ in formula (5) include a single bond and an alkylene group having 1 to 6 carbon atoms. More specifically, the alkylene group having 1 to 6 carbon atoms includes a straight chain alkylene group having 1 to 6 carbon atoms.
Examples of R ₃ in formula (5) include a single bond and an alkylene group having 1 to 6 carbon atoms. More specifically, the alkylene group having 1 to 6 carbon atoms includes a straight chain alkylene group having 1 to 6 carbon atoms.
Examples of X ₁ in formula (5) include a hydrogen atom and a phenyl group.
Examples of X ₂ in formula (5) include a hydrogen atom and a phenyl group.
Ar in formula (5) includes, for example, a phenyl group.

The total carbon number of R ₁ X ₁ , R ₂ X ₂ and R ₃ in formula (5) is not particularly limited as long as it is 1 or more, but may be 2 or more.
Further, the total carbon number of R ₁ , R ₂ , and R ₃ in formula (5) may be, for example, 18 or less, 15 or less, or 10 or less. .
Furthermore, when X ₁ and X ₂ in formula (5) are hydrogen atoms, the total number of carbon atoms in R ₁ , R ₂ , and R ₃ is not particularly limited as long as it is 1 or more, but even if it is 2 or more, good.
In addition, when at least one of X ₁ and X ₂ in formula (5) is an aromatic hydrocarbon group which may have a substituent, the total carbon number of R ₁ , R ₂ , and R ₃ is 0. It may be.

In formula (5), the ring formed by R ₁ X ₁ , R ₂ X ₂ , _{and the carbon atoms bonded to R 1} _X ₁ and R ₂ Examples include hydrocarbon rings having 3 to 13 carbon atoms, which may be optional. The binding group is as described above.

By using the structure of the above compound, it is easy to achieve high-speed response when the voltage is turned off, reduced burn-in, high backlight transmittance in a low-temperature environment, and low-voltage driving.

The block segment (A) is mainly swollen by the liquid crystal in a thin film state and plays the role of forming a weak anchoring film. Since the physical properties of the weak anchoring film vary greatly depending on the molecular weight of the block segment (A), optimization of the molecular weight is not necessary but is important. From the viewpoint of forming a good weak anchoring film, the molecular weight of the block segment (A) is preferably 1,000 to 100,000, more preferably 3,000 to 50,000. Note that this molecular weight is a number average molecular weight (Mn) in terms of polystyrene measured by gel permeation chromatography (GPC). Further, the molecular weight distribution PDI (Mw/Mn), which is expressed as the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn) in terms of polystyrene measured by GPC, is preferably 3.0 or less, and more preferably is 2.0 or less.

The block segment (A) may be a single polymer of the above compounds, or a combination of multiple compounds may be used. When used in combination, random copolymerization or block copolymerization may be used. When combining with a compound species that is compatible with liquid crystal, the ratio is not particularly limited regardless of the combination method. When combined with a compound species that becomes insolubilized in liquid crystal as described below, from the viewpoint of maintaining properties, the preferred combination ratio of compound species that becomes insolubilized in liquid crystal is 30 mol% or less, more preferably 20 mol% or less, but there are no limitations. do not. It is preferable to use these combination methods, the types of compounds to be combined, and the combination ratio within a range that allows desired physical properties, display characteristics, electrical characteristics, etc. to be obtained.

The block segment (B) contributes to the stability of the weakly anchoring liquid crystal alignment film in a thin film state.

Block segment (B) is preferably a trialkoxysilyl group, an isocyanate group, a blocked isocyanate group, an epoxy group, an oxetane group, a vinyl group, an allyl group, an oxazoline group, an amino group, a protected amino group, an aniline group, a protected aniline group. , hydroxy group, protected hydroxy group, phenol group, protected phenol group, thiol group, protected thiol group, thiophenol group, protected thiophenol group, aldehyde group, carboxy group, maleimide group, N-hydroxysuccinimide ester group, bonding group Aromatic hydrocarbon group having 5 to 18 carbon atoms which may be inserted, an aromatic heterocyclic group having 5 to 18 carbon atoms which may have a bonding group inserted, cinnamic acid group, cinnamic acid aromatic ester group, It has a side chain structure having at least one functional group selected from the group consisting of a cinnamic acid alkyl ester group, a cinnamyl group, a phenylbenzoate group, an azobenzene group, an N-benzylideneaniline group, a stilbene group, and a tolan group. Specific examples of the bonding group include the specific examples of the bonding group listed in the explanation of formula (2).
In that case, the block segment (B) contains, for example, a polymerizable compound having the above functional group and a polymerizable group having a polymerizable unsaturated hydrocarbon group as a constituent component.

An example of the polymerizable compound used to form the block segment (B) is represented by the following formula (6).

(In formula (6-Z), L is a trialkoxysilyl group, an isocyanate group, a blocked isocyanate group, an epoxy group, an oxetane group, a vinyl group, an allyl group, an oxazoline group, an amino group, a protected amino group, an aniline group, a protected aniline group) group, hydroxy group, protected hydroxy group, phenol group, protected phenol group, thiol group, protected thiol group, thiophenol group, protected thiophenol group, aldehyde group, carboxy group, maleimide group, N-hydroxysuccinimide ester group, bonding group Aromatic hydrocarbon group having 5 to 18 carbon atoms which may have a bonding group inserted therein, an aromatic heterocyclic group having 5 to 18 carbon atoms which may have a bonding group inserted therein, a cinnamic acid group, a cinnamic acid aromatic ester group , a cinnamic acid alkyl ester group, a cinnamyl group, a phenylbenzoate group, an azobenzene group, an N-benzylideneaniline group, a stilbene group, and a tolan group. J is a single bond or has 1 to 1 carbon atoms. 6 represents an aliphatic hydrocarbon group.When K is bonded to an aromatic hydrocarbon group, it represents a linking group selected from a single bond, ether bond, ester bond, amide bond, urea bond, urethane bond, and thioether bond. In other cases, it indicates a single bond. * represents a binding site. m is an integer from 1 to 3. When m is 2 or 3, multiple K and L may be the same. (However, if J is a single bond, m is 1.)

The block segment (B) has a side chain structure that is not compatible with the liquid crystal or becomes incompatible with the liquid crystal upon firing. Compounds that are incompatible with the liquid crystal used to form the block segment (B) include highly polar compounds and compounds with a rigid structure. Examples of the compound species that are no longer compatible with the thermosetting compound species include thermosetting compound species.

An example of the polymerizable compound used to form the block segment (B) is a compound having a polymerizable group having a polymerizable unsaturated hydrocarbon group and a highly polar structure.
The above highly polar structure preferably has the following structure. However, it is not limited to these.

(X and Y each independently represent an oxygen atom or a sulfur atom. R ₁ and R ₂ each independently represent a single bond or an alkylene group having 1 to 18 carbon atoms. _{R 3} represents an alkylene group having 1 to 18 carbon atoms. Represents an alkyl group. _{One of A 1} , A ₂ and A ₃ represents N, and the remaining two represent CH. One of A ₄ and A ₅ represents N, and the remaining one represents CH. (* represents the binding site.)

An example of the polymerizable compound used to form the block segment (B) is a compound having a polymerizable group having a polymerizable unsaturated hydrocarbon group and a rigid structure.
The above rigid structure preferably has the following structure. However, it is not limited to these.

(X, Y, and Z each independently represent an oxygen atom or a sulfur atom. R ₁ and R ₂ each independently represent a single bond or an alkylene group having 1 to 18 carbon atoms. R ₃ represents a carbon number 1 ~18 represents an alkyl group. * represents a bonding site, n represents an integer from 1 to 5.)

An example of the polymerizable compound used to form the block segment (B) is a compound having a polymerizable group having a polymerizable unsaturated hydrocarbon group and a thermosetting structure.
The above thermosetting structure preferably has the following structure. However, it is not limited to these.

(X, Y and Z each independently represent an oxygen atom or a sulfur atom. R ₁ , R ₂ and R ₃ each independently represent an alkyl group having 1 to 18 carbon atoms. R ₄ and R ₅ are Each independently represents a single bond or an alkylene group having 1 to 18 carbon atoms. * represents a bonding site.)

In the present invention, the following structures are preferred as the polymerizable group having a polymerizable unsaturated hydrocarbon group.

(In the formula, R ₁ and R ₂ each independently represent a hydrogen atom or a linear or branched alkyl group having 1 to 12 carbon atoms, and X, Y, and Z each independently represent an oxygen atom or a sulfur atom. *, * ¹ and * ² represent bonding sites, and either one of * ¹ and * ² may be replaced with a hydrogen atom or a linear or branched alkyl group having 1 to 12 carbon atoms.)

The block segment (B) is mainly responsible for stabilizing the thin film state and does not significantly affect the physical properties of the weak anchoring film. It is sufficient that the block segment (B) complements the stability of the membrane, and the optimal molecular weight that can complement the stability of the membrane is not particularly limited because it varies depending on the type of compound used. Further, depending on the type of compound used, advantages can be obtained in solvent selectivity and coating properties, so it is preferable to control the type of compound constituting the block segment (B) and its molecular weight depending on the use and purpose.

For the block segment (B), the above polymerizable compounds may be used alone, or a plurality of compounds may be used in combination. As mentioned above, the block segment (B) is a block segment that only contributes to the stability of the membrane, and does not significantly contribute to the weak anchoring properties. Therefore, as long as the stabilization of the membrane is complemented, the type of compound to be combined and the method of combination are Not particularly limited.

One embodiment of the polymer (α) is characterized in that it is a copolymer having a block segment (A) that is compatible with the liquid crystal and a block segment (B) that is insoluble in the liquid crystal or becomes insolubilized in the liquid crystal by firing, The number of blocks is not limited, and a configuration having a plurality of block segments, such as (A)-(B)-(A), for example, may be used, and the number and combination of block segments are not particularly limited. It is also possible to introduce block segments that impart electrical properties. On the other hand, from the viewpoint of ease of synthesis, the number of block segments is preferably about 2 to 4, and from the viewpoint of membrane stability, the terminal block segment of the polymer is preferably block segment (B).

As mentioned above, the block segment (A) that is compatible with the liquid crystal controls weak anchoring properties, and the molecular weight of the block segment (A) greatly affects the properties. The molecular weight ratio is not limited.

The polymer (α) can be obtained, for example, by living polymerization. Living polymerization is a polymerization reaction in which side reactions such as chain transfer reactions and termination reactions are not involved during the polymerization reaction, and it is possible to obtain a polymer with a narrow molecular weight distribution and a highly controlled structure. For example, one method is to suppress the deactivation of the active site by introducing a stable covalent species called a dormant species into the polymerization active site, thereby preventing the occurrence of side reactions such as chain transfer reactions and termination reactions. Living polymerizations include those using radicals, cations, and anions as active species, and it is important to select one depending on the structure and properties of the polymerizable compound used.
When obtaining the block polymer that is the polymer (α), there is no need to particularly limit the polymerization method, but cationic polymerization and anionic polymerization may use alkali metals, metal complexes, or halogen compounds to generate active species. In most liquid crystal displays, the contamination of metal residues and halogen compounds can cause burn-in and display defects, so it is preferable to use radical polymerization that does not use metals or halogen compounds as much as possible. Examples of living radical polymerization include living radical polymerization (NMP) using nitroxide as a dormant species, atom transfer radical polymerization (ATRP) using a metal complex, and reversible addition/elimination chain transfer polymerization (RAFT) using a sulfur compound as a dormant. Polymerization), living radical polymerization (TERP) using an organic tellurium compound, etc., and reversible transfer catalytic polymerization (RTCP) using an alkyl iodide compound as a dormant species and using a phosphorus compound, alcohol, etc. as a catalyst, etc. are preferred. Examples of the polymerization method include living radical polymerization such as NMP, RTCP, and RAFT polymerization, and NMP or RAFT polymerization is particularly preferred.

When using NMP, examples of the polymerization initiator include 2,2'-azobis(isobutyronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), benzoyl peroxide, 1,1 Examples include '-bis(tert-butylperoxy)cyclohexane and hydrogen peroxide. The proportion of the polymerization initiator used is usually 0.000001 to 0.1 part by mole, preferably 0.00001 to 0.01 part by mole, per 1 part by mole of the monomer used. Examples of the nitroxide include compounds represented by the following formulas (N-1) to (N-12). The proportion of nitroxide used is usually 0.000001 to 0.1 part by mole, preferably 0.00001 to 0.01 part by mole, per 1 part by mole of the monomer used. The reaction temperature in the above polymerization is preferably 20 to 200°C, more preferably 40 to 150°C, and the reaction time is preferably 1 to 168 hours, more preferably 8 to 72 hours.

When using RTCP, in addition to low-molecular dormant species (dormant species) that contribute to the expression of living properties, it is necessary to use an iodide catalyst or a hydride catalyst and a polymerization initiator for the purpose of promoting the reaction.
Examples of the polymerization initiator used include 2,2'-azobis(isobutyronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), benzoyl peroxide, and 1,1'-bis(tert). -butylperoxy)cyclohexane, hydrogen peroxide, etc. The proportion of the polymerization initiator used is usually 0.000001 to 0.1 part by mole, preferably 0.00001 to 0.01 part by mole, per 1 part by mole of the monomer used.
Examples of low-molecular dormant species include compounds represented by the following formulas (Q-1) to (Q-3). The proportion of the low molecular weight dormant species used is usually 0.000001 to 0.1 mol part, preferably 0.00001 to 0.01 mol part, per 1 mol part of the monomer used.
Examples of the iodide catalyst include compounds represented by the following formulas (P-1) to (P-4). The proportion of the iodide catalyst used is usually 0.000001 to 0.1 part by mole, preferably 0.00001 to 0.01 part by mole, per 1 part by mole of the monomer used.
Examples of the hydride catalyst include compounds represented by the following formulas (O-1) to (O-6). The proportion of the hydride catalyst used is 0.000001 to 0.1 part by mole, preferably 0.00001 to 0.01 part by mole, per 1 part by mole of the monomer used.
Generally, the reaction temperature in the above polymerization is preferably 20 to 200°C, more preferably 40 to 150°C, and the reaction time is preferably 1 to 168 hours, more preferably 8 to 72 hours.

When using RAFT polymerization, examples of the polymerization initiator used include 2,2'-azobis(isobutyronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), benzoyl peroxide, 1, Examples include 1'-bis(tert-butylperoxy)cyclohexane and hydrogen peroxide. The proportion of the polymerization initiator used is usually 0.000001 to 0.1 part by mole, preferably 0.00001 to 0.01 part by mole, per 1 part by mole of the monomer used. As the chain transfer agent (RAFT agent), trithiocarbonate, dithiobenzoate, dithiocarbamate, and xanthate are preferable, and specific examples include compounds represented by the following formulas (R-1) to (R-24). can be mentioned. The proportion of the chain transfer agent used is usually 0.000001 to 0.1 part by mole, preferably 0.00001 to 0.01 part by mole, per 1 part by mole of the monomer used. The reaction temperature in the above polymerization is preferably 20 to 200°C, more preferably 40 to 150°C, and the reaction time is preferably 1 to 168 hours, more preferably 8 to 72 hours.

Living radical properties are expressed in RAFT polymerization because most of the living chains are in the dormant type (dormant type), and there are compounds that can reversibly inactivate the growing radical species. This is because a fast equilibrium exists between the chains.

By using RAFT polymerization, it is possible to control polymer terminals, advanced molecular weight control, and molecular weight distribution control.

In order to precisely synthesize a functional polymer using RAFT polymerization, it is necessary to select an appropriate chain transfer agent in consideration of the reactivity of the monomer.

In RAFT polymerization, polymer terminals can be controlled by thermally and chemically modifying the RAFT terminals present at the growing terminals. In the case of thermal modification, the terminal can be modified into an unsaturated hydrocarbon group by heating at a temperature higher than the temperature at which the RAFT agent used is thermally decomposed. In addition, in the case of chemical modification, the terminal can be modified into a thiol bond by bringing it into contact with a primary amine, secondary amine, etc., accompanied by aminolysis. Furthermore, it is possible to provide a new block segment at the end by bringing it into contact with a new monomer and a radical generator.

In RAFT polymerization, molecular weight can be controlled by using the following formula (eq1). Specifically, the number average molecular weight (Mn) changes linearly with the ratio of the molar concentration of the monomer to the molar concentration of the chain transfer agent, making it possible to control the molecular weight.

(In the above formula (eq1), Mn _(theor) represents the molecular weight of the polymer, [Monomer] ₀ represents the molar concentration of the monomer, [CTA] ₀ represents the molar concentration of the chain transfer agent, and M _monomer represents the molar concentration of the monomer. represents the molecular weight of the chain transfer agent, conv. represents the polymerization conversion rate, and _MCTA represents the molecular weight of the chain transfer agent.)

In addition, when the copolymer obtained by the above polymerization is dissolved in the reaction solution, the reaction solution may be used as it is for preparing the liquid crystal aligning agent, or the copolymer contained in the reaction solution may be isolated. Then, it may be used for preparing a liquid crystal aligning agent.

The organic solvent used in the synthesis of the copolymer (polymer (α)) may be any solvent as long as it does not chemically react with the compound species constituting the copolymer and does not scavenge radicals. For example, N,N-dimethylformamide, N,N-diethylformamide, N,N-dibutylformamide, N,N-dimethylacetamide, N,N-diethylacetamide, N,N-dipropylacetamide, N,N-dimethyl Propionamide, N,N-diethylpropionamide, 3-methoxy-N,N-dimethylpropanamide, N-methylformamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 2-pyrrolidone, 1, 3-dimethyl-2-imidazolidinone, N-methyl-ε-caprolactam, dimethylsulfoxide, tetramethylurea, pyridine, dimethylsulfone, hexamethylphosphoramide, γ-butyrolactone, isopropyl alcohol, methoxymethylpentanol, dipentene, Ethyl amyl ketone, methyl nonyl ketone, methyl ethyl ketone, methyl isoamyl ketone, methyl isopropyl ketone, methyl cellosolve, ethyl cellosolve, methyl cellosolve acetate, butyl cellosolve acetate, ethyl cellosolve acetate, butyl carbitol, ethyl carbitol, ethylene glycol, ethylene glycol monoacetate , ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether (butyl cellosolve), propylene glycol, propylene glycol monoacetate, propylene glycol monomethyl ether, propylene glycol monobutyl ether, propylene glycol-tert-butyl ether, dipropylene glycol monomethyl ether, propylene glycol monomethyl ether Acetate, diethylene glycol, diethylene glycol monoacetate, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, dipropylene glycol monoacetate monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monoacetate monoethyl ether, dipropylene glycol monopropyl ether, dipropylene glycol mono Acetate monopropyl ether, 3-methyl-3-methoxybutyl acetate, tripropylene glycol methyl ether, 3-methyl-3-methoxybutanol, diisopropyl ether, ethyl isobutyl ether, diisobutylene, amyl acetate, butyl butyrate, butyl ether, diisobutyl Ketone, methylcyclohexene, propyl ether, dihexyl ether, 1,4-dioxane, n-hexane, n-pentane, n-octane, cyclohexane, 2-ethyl-1-hexanol, benzene, xylene, toluene, ethylbenzene, isopropyl Benzene, tert-butylbenzene, tetrahydrofuran, diethyl ether, cyclohexanone, ethylene carbonate, propylene carbonate, methyl lactate, ethyl lactate, methyl acetate, ethyl acetate, n-butyl acetate, propylene glycol monoethyl ether acetate, methyl pyruvate, pyruvic acid Ethyl, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, methyl 3-ethoxypropionate, ethyl 3-ethoxypropionate, 3-ethoxypropionic acid, 3-methoxypropionic acid, propyl 3-methoxypropionate, 3 -Butyl methoxypropionate, diglyme, 4-hydroxy-4-methyl-2-pentanone, 3-ethoxy-N,N-dimethylpropanamide, 3-butoxy-N,N-dimethylpropanamide, propyl pyruvate, pyruvic acid Butyl, pentyl pyruvate, hexyl pyruvate, 2-ethylhexyl pyruvate, methyl acetoacetate, ethyl acetoacetate, propyl acetoacetate, butyl acetoacetate, pentyl acetoacetate, hexyl acetoacetate, 2-ethylhexyl acetoacetate, levulinic acid Methyl, ethyl levulinate, propyl levulinate, butyl levulinate, pentyl levulinate, hexyl levulinate, 2-ethylhexyl levulinate, dimethyl malonate, dimethyl succinate, dimethyl glutarate, dimethyl adipate, dimethyl phthalate, maleic acid. Dimethyl acid, diethyl malonate, diethyl succinate, diethyl glutarate, diethyl adipate, diethyl phthalate, diethyl maleate, dipropyl malonate, dipropyl succinate, dipropyl glutarate, dipropyl adipate, dipropyl phthalate, dipropyl maleate , dibutyl malonate, dibutyl succinate, dibutyl glutarate, dibutyl adipate, dibutyl phthalate, dibutyl maleate, dipentyl malonate, dipentyl succinate, dipentyl glutarate, dipentyl adipate, dipentyl phthalate, dipentyl maleate, malon Dihexyl acid, dihexyl succinate, dihexyl glutarate, dihexyl adipate, dihexyl phthalate, dihexyl maleate, di-2-ethylhexyl malonate, 2-ethylhexyl succinate, 2-ethylhexyl glutarate, 2-adipate Ethylhexyl, 2-ethylhexyl phthalate, 2-ethylhexyl maleate (hereinafter also referred to as "specific organic solvent"). Note that in this specification, "specific solvent" and "specific organic solvent" refer to different solvents. ) etc. These organic solvents may be used alone or in combination.

(Graft copolymer [polymer (β)])
One embodiment of the "graft copolymer" in the present invention is a graft copolymer contained in a weakly anchoring liquid crystal aligning agent. Weak anchoring liquid crystal alignment agents are used to form a film for aligning liquid crystals used in liquid crystal display elements, that is, a liquid crystal alignment film. Moreover, the weak anchoring liquid crystal alignment agent is used for forming a liquid crystal alignment film of a liquid crystal cell having a liquid crystal and a liquid crystal alignment film.
The graft copolymer [polymer (β)] has a trunk polymer and a branch polymer bonded to the trunk polymer as a side chain of the trunk polymer.
The branch polymer is compatible with the liquid crystal.
The backbone polymer is not compatible with the liquid crystal or becomes insoluble in the liquid crystal upon firing.

Graft copolymer is a general term for polymers with a branched structure, and refers to a polymer that simultaneously has a polymer corresponding to a "trunk" and a polymer corresponding to a "branch" bonded to the trunk as a side chain of the trunk. A graft copolymer is used in one embodiment of the liquid crystal aligning agent of the present invention. It is characterized by being insoluble in liquid crystals or becoming insoluble in liquid crystals by firing. That is, a branch polymer that is compatible with the liquid crystal dissolves in the liquid crystal and swells, thereby contributing to the formation of a weak anchoring state, while as a graft copolymer, it is not compatible with the liquid crystal, or it becomes insolubilized in the liquid crystal by baking. By preventing the elution of the graft copolymer to the liquid crystal, fixing it to the substrate, crosslinking the polymers with each other, and crosslinking with the sealing component, it is possible to obtain a weakly anchored liquid crystal display element with excellent film hardness and seal adhesion strength. can.

The present applicant has proposed that a weakly anchoring liquid crystal aligning agent containing a polymer (β) is a weakly anchoring liquid crystal aligning agent that can be easily produced, has good coating properties, and has good adhesion to a seal. We have discovered that this is a weakly anchoring liquid crystal aligning agent that does not generate a pretilt angle and can provide a weakly anchoring liquid crystal aligning film that simultaneously achieves low voltage drive and high-speed response when the voltage is turned off, and has filed an application. Japanese Patent Application No. 2021-156886 and WO2023/048278. By being cited herein, the content of this application is incorporated herein to the same extent as if it were expressly set forth in its entirety.)

The graft copolymer of the present invention is characterized in that it has branch polymers that are compatible with liquid crystals, but are not compatible with liquid crystals or become insolubilized in liquid crystals upon firing. In addition, in order to prevent the graft copolymer from being compatible with the liquid crystal, or to make the graft copolymer insoluble in the liquid crystal by baking, the backbone polymer has a structure that is not compatible with the liquid crystal or becomes insoluble in the liquid crystal by baking. It has become.
The graft copolymer of the present invention has a branch polymer that is compatible with liquid crystals and a trunk polymer that is not compatible with liquid crystals or becomes insolubilized by heat etc., and these are preferably connected in a random arrangement by free radical polymerization. . This provides high seal adhesion, solvent selectivity, and coating properties.

The structure of the branch polymer that is compatible with the liquid crystal is not particularly limited as long as it is compatible with the liquid crystal, but for example, the branch polymer can be obtained by using a macromonomer represented by the following formula (7). can. Furthermore, the structure of the backbone polymer that is incompatible with the liquid crystal or becomes insolubilized by firing is not particularly limited as long as it satisfies these properties, but for example, the backbone polymer may be obtained by using a compound represented by the above formula (6). Can be done. In obtaining the backbone polymer, for example, only one type of compound represented by the above formula (6) may be used, or if the compound represented by the above formula (6) is used, one type of compound other than this may be used. Alternatively, a plurality of compounds may be combined.
In other words, the branched polymer in the polymer (β) is derived from, for example, a macromonomer represented by the following formula (7).
Further, the backbone polymer in the polymer (β) contains, for example, a compound represented by the above formula (6) as a constituent component.
The formula of a specific compound is shown below.

(In formula (7), P represents a polymerizable group having a polymerizable unsaturated hydrocarbon group, and Q represents a monomer containing at least one of the compounds represented by formulas (2) to (5) above. It is a structure obtained by polymerization, and n is an integer of 1 to 2. When n is 2, the two Qs may be the same or different.)

The monomer used in the synthesis of the branched polymer may be a single component, or a combination of multiple monomers may be used. Further, other monomers capable of radical polymerization reaction, which will be described below, may be used in combination.

In the polymer (β), the branched polymers are largely involved in the expression of weak anchoring properties. Optimization of the molecular weight is important because the physical properties of the weak anchoring film change depending on the molecular weight of the branch polymer. From the viewpoint of forming a good weak anchoring film, the preferred number average molecular weight of the branched polymer is 1,000 to 100,000, more preferably 3,000 to 50,000, and the weight average molecular weight (Mw) and number The molecular weight distribution (PDI) expressed as a ratio to the average molecular weight (Mn) is preferably 3.0 or less, more preferably 2.0 or less. Note that when the graft copolymer is synthesized by a grafting through method using a macromonomer, the molecular weight here corresponds to the molecular weight of the macromonomer.

The structure in which the terminal end of the branched polymer is removed (for example, the structure of Q in formula (7)) may be a single polymer structure using only one type of monomer represented by the above formulas (2) to (5), or a structure in which multiple monomers are used. A copolymer structure consisting of a combination of monomers may also be used. When a plurality of monomers are combined, random copolymerization or block copolymerization may be used. When the monomers represented by the above formulas (2) to (5) are combined, the ratio is not particularly limited regardless of the method of combination. When combined with a compound species that insolubilizes liquid crystals as described below, the preferred combination ratio of monomers that insolubilize liquid crystals is 30 mol% or less, more preferably 20 mol% or less, from the viewpoint of maintaining properties, but there is no limitation. . These synthesis methods, monomers to be combined, and combination ratios are preferably used within a range that allows desired physical properties, display characteristics, electrical characteristics, etc. to be obtained.

The macromonomer represented by formula (7), which is the raw material for forming the branch polymer of the graft copolymer that is the polymer (β), can be obtained, for example, by a combination of living polymerization, chain transfer polymerization, or polymer terminal modification reaction. Can be done. Furthermore, it has been reported that a polymer having a radically polymerizable unsaturated bond in the terminal group can be obtained by continuous bulk polymerization at a high temperature of 200° C. or higher (Toagosei Research Annual Report TREND 2002 No. 5).
When obtaining a macromonomer that is a raw material for a graft copolymer, there is no need to particularly limit the polymerization method, but cationic polymerization and anionic polymerization may use alkali metals, metal complexes, or halogen compounds to generate active species. In liquid crystal displays, the contamination of metal residues and halogen compounds can cause burn-in and display defects, so it is preferable to use radical polymerization that uses as few metals and halogen compounds as possible. Examples of living radical polymerization include nitroxide-mediated radical polymerization (NMP) using nitroxide as a dormant species, atom transfer radical polymerization (ATRP) using a metal complex, and reversible addition/fragmentation chain transfer (RAFT) using a sulfur compound as a dormant. ) polymerization, living radical polymerization (TERP) using an organic tellurium compound, etc., reversible transfer catalytic polymerization (RTCP) using an alkyl iodide compound as a dormant species, and using a phosphorus compound, alcohol, etc. as a catalyst, etc. are preferred. Examples of the polymerization method include living radical polymerization such as NMP, RTCP, and RAFT polymerization, and NMP or RAFT polymerization is particularly preferred. It is also preferable to use chain transfer polymerization.

When chain transfer polymerization is used, examples of the polymerization initiator used include 2,2'-azobis(isobutyronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), benzoyl peroxide, 1 , 1'-bis(tert-butylperoxy)cyclohexane, hydrogen peroxide, and the like. The proportion of the polymerization initiator used is usually 0.000001 to 0.1 part by mole, preferably 0.00001 to 0.01 part by mole, per 1 part by mole of the monomer used. As the chain transfer agent, it is preferable to use thiols, and specific examples include compounds represented by the following formulas (S-1) to (S-16). The proportion of the chain transfer agent used is usually 0.000001 to 0.1 part by mole, preferably 0.00001 to 0.01 part by mole, per 1 part by mole of the monomer used. The reaction temperature in the above polymerization is preferably 20 to 200°C, more preferably 40 to 150°C, and the reaction time is preferably 1 to 168 hours, more preferably 8 to 72 hours.

(In formulas (S-1) to (S-16), Me represents a methyl group, and Et represents an ethyl group.)

The organic solvent used in the chain transfer polymerization reaction is not particularly limited as long as it dissolves the produced polymer. Specific examples include the above-mentioned specific organic solvents, which may be used alone or in combination of two or more.
Furthermore, even a solvent that does not dissolve the produced polymer may be mixed with the above-mentioned organic solvent and used as long as the produced polymer does not precipitate.
Note that in chain transfer polymerization, oxygen in an organic solvent becomes a cause of inhibiting the polymerization reaction, so it is preferable to use an organic solvent that has been degassed to the extent possible.

By using chain transfer polymerization, it is possible to control polymer terminals, molecular weight, and molecular weight distribution.

In chain transfer polymerization, polymers are obtained by competitive reactions between chain transfer and growth reactions. The molecular weight and molecular weight distribution of a polymer obtained by chain transfer polymerization are determined by the chain transfer constant (Cs), which is expressed as the quotient of the chain transfer rate constant (kc) and the growth rate constant (kp). Generally, in chain transfer polymerization, a structure in which Cs is in the range of 1 to 60 is preferable, and it is important to use the monomer species and chain transfer agent species and the correct combination of these.

The chain transfer constant (Cs) varies greatly depending on the type of monomer used and the type of chain transfer agent, so it is necessary to select it correctly.

The main synthesis methods for graft copolymers include the Grafting-to method, in which a branch polymer is directly introduced into a trunk polymer, and the Grafting-from method, in which a monomer is polymerized from a macroinitiator (a trunk polymer having a polymerization active site) to extend a branch polymer. The synthesis method is not limited, as any method can be used.

The method for producing the graft copolymer is not particularly limited, and any commonly used industrial method can be used. Specifically, it can be produced by radical polymerization, cationic polymerization, or anionic polymerization using the above-mentioned monomers. Among these, radical polymerization is particularly preferred from the viewpoint of ease of reaction control.

As the polymerization initiator for radical polymerization, known compounds such as radical polymerization initiators (radical thermal polymerization initiators, radical photopolymerization initiators) and reversible addition-fragmentation chain transfer (RAFT) polymerization reagents may be used. Can be done.

A radical thermal polymerization initiator is a compound that generates radicals when heated above the decomposition temperature. Such radical thermal polymerization initiators include, for example, ketone peroxides (methyl ethyl ketone peroxide, cyclohexanone peroxide, etc.), diacyl peroxides (acetyl peroxide, benzoyl peroxide, etc.), hydroperoxides (peroxide Hydrogen, tert-butyl hydroperoxide, cumene hydroperoxide, etc.), dialkyl peroxides (di-tert-butyl peroxide, dicumyl peroxide, dilauroyl peroxide, etc.), peroxyketals (dibutyl peroxycyclohexane) etc.), alkyl peroxy esters (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'-bis(2-hydroxyethyl)azobisisobutyronitrile, etc.), and the like. The radical thermal polymerization initiators may be used alone or in combination of two or more.

The radical photopolymerization initiator is not particularly limited as long as it is a compound that initiates radical polymerization by light irradiation. Such radical photopolymerization initiators include benzophenone, Michler's ketone, 4,4'-bis(diethylamino)benzophenone, xanthone, thioxanthone, isopropylxanthone, 2,4-diethylthioxanthone, 2-ethylanthraquinone, acetophenone, 2-hydroxy -2-Methylpropiophenone, 2-hydroxy-2-methyl-4'-isopropylpropiophenone, 1-hydroxycyclohexylphenyl ketone, isopropylbenzoin ether, isobutylbenzoin ether, 2,2-diethoxyacetophenone, 2,2 -dimethoxy-2-phenylacetophenone, camphorquinone, benzanthrone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1-( 4-morpholinophenyl)-1-butanone, ethyl 4-dimethylaminobenzoate, isoamyl 4-dimethylaminobenzoate, 4,4'-bis(tert-butylperoxycarbonyl)benzophenone, 3,4,4'-tris( tert-butylperoxycarbonyl)benzophenone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2-(4'-methoxystyryl)-4,6-bis(trichloromethyl)-s-triazine, 2-(3' , 4'-dimethoxystyryl)-4,6-bis(trichloromethyl)-s-triazine, 2-(2',4'-dimethoxystyryl)-4,6-bis(trichloromethyl)-s-triazine, 2 -(2'-methoxystyryl)-4,6-bis(trichloromethyl)-s-triazine, 2-(4'-pentyloxystyryl)-4,6-bis(trichloromethyl)-s-triazine, 4- [p-N,N-di(ethoxycarbonylmethyl)]-2,6-di(trichloromethyl)-s-triazine, 1,3-bis(trichloromethyl)-5-(2'-chlorophenyl)-s- Triazine, 1,3-bis(trichloromethyl)-5-(4'-methoxyphenyl)-s-triazine, 2-(p-dimethylaminostyryl)benzoxazole, 2-(p-dimethylaminostyryl)benzothiazole, 2-mercaptobenzothiazole, 3,3'-carbonylbis(7-diethylaminocoumarin), 2-(o-chlorophenyl)-4,4',5,5'-tetraphenyl-1,2'-biimidazole, 2 , 2'-bis(2-chlorophenyl)-4,4',5,5'-tetrakis(4-ethoxycarbonylphenyl)-1,2'-biimidazole, 2,2'-bis(2,4-dichlorophenyl) )-4,4',5,5'-tetraphenyl-1,2'-biimidazole, 2,2'-bis(2,4-dibromophenyl)-4,4',5,5'-tetraphenyl -1,2'-biimidazole, 2,2'-bis(2,4,6-trichlorophenyl)-4,4',5,5'-tetraphenyl-1,2'-biimidazole, 3-( 2-Methyl-2-dimethylaminopropionyl)carbazole, 3,6-bis(2-methyl-2-morpholinopropionyl)-9-n-dodecylcarbazole, 1-hydroxycyclohexyl phenylketone, bis(η5-2,4- cyclopentadien-1-yl)-bis(2,6-difluoro-3-(1H-pyrrol-1-yl)-phenyl)titanium, 3,3',4,4'-tetrakis(tert-butylperoxycarbonyl) Benzophenone, 3,3',4,4'-tetrakis(tert-hexylperoxycarbonyl)benzophenone, 3,3'-bis(methoxycarbonyl)-4,4'-bis(tert-butylperoxycarbonyl)benzophenone, 3, 4'-bis(methoxycarbonyl)-4,3'-bis(tert-butylperoxycarbonyl)benzophenone, 4,4'-bis(methoxycarbonyl)-3,3'-bis(tert-butylperoxycarbonyl)benzophenone, 2-(3-Methyl-3H-benzothiazol-2-ylidene)-1-naphthalen-2-yl-ethanone, 2-(3-methyl-1,3-benzothiazol-2(3H)-ylidene)-1 -(2-benzoyl)ethanone and the like. The radical photopolymerization initiators may be used alone or in combination of two or more.

The radical polymerization method is not particularly limited, and emulsion polymerization, suspension polymerization, dispersion polymerization, precipitation polymerization, bulk polymerization, solution polymerization, and the like can be used.
The organic solvent used in the radical polymerization reaction is not particularly limited as long as it dissolves the produced polymer. Specific examples include the above-mentioned specific organic solvents. These organic solvents may be used alone or in combination of two or more.

Furthermore, even a solvent that does not dissolve the produced polymer may be mixed with the above-mentioned organic solvent and used as long as the produced polymer does not precipitate.
In addition, since oxygen in an organic solvent becomes a cause of inhibiting the polymerization reaction in radical polymerization, it is preferable to use an organic solvent that has been degassed to the extent possible.
In addition, when the graft copolymer obtained by the above polymerization is dissolved in the reaction solution, the reaction solution may be used as it is for preparing the liquid crystal aligning agent, or the graft copolymer contained in the reaction solution may be dissolved in the reaction solution. After separation, the liquid crystal aligning agent may be prepared.
The polymerization temperature during radical polymerization can be any temperature in the range of 30 to 150°C, but is preferably in the range of 50 to 100°C. In addition, the reaction can be carried out at any concentration, but if the concentration is too low, it will be difficult to obtain a high molecular weight polymer, and if the concentration is too high, the viscosity of the reaction solution will become too high, making it difficult to stir uniformly. Therefore, the monomer concentration is preferably 1 to 50% by weight, more preferably 5 to 40% by weight. The initial stage of the reaction can be carried out at a high concentration, and then an organic solvent can be added.

In the radical polymerization reaction described above, if the ratio of the radical polymerization initiator to the monomer is large, the molecular weight of the obtained polymer will be small, and if it is small, the molecular weight of the obtained polymer will be large. The amount is preferably 0.1 to 10 mol% based on the monomer to be polymerized. Furthermore, various monomer components, solvents, initiators, etc. can be added during polymerization.

The polymer produced from the reaction solution obtained by the above reaction can be recovered by pouring the reaction solution into a poor solvent to precipitate it, but this reprecipitation treatment is not essential. Examples of the poor solvent used for precipitation include methanol, acetone, hexane, heptane, butyl cellosolve, heptane, methyl ethyl ketone, methyl isobutyl ketone, ethanol, toluene, benzene, diethyl ether, methyl ethyl ether, water, and the like. The polymer precipitated in a poor solvent can be collected by filtration and then dried under normal pressure or reduced pressure, at room temperature or by heating. Further, by repeating the operation of redissolving the recovered polymer in an organic solvent and reprecipitation recovery 2 to 10 times, the amount of impurities in the polymer can be reduced. Examples of the poor solvent in this case include alcohols, ketones, hydrocarbons, etc. It is preferable to use three or more kinds of poor solvents selected from these, since the efficiency of purification will further increase.

Considering the strength of the resulting coating film, workability during coating film formation, and uniformity of the coating film, the weight average molecular weight of the graft copolymer measured by GPC (Gel Permeation Chromatography) method is 2,000 to 5. ,000,000 is preferred, and 5,000 to 2,000,000 is more preferred.

Graft copolymers have branch polymers that are compatible with liquid crystals and trunk polymers that are incompatible with liquid crystals or become insolubilized by heat, etc., and are characterized by being linked in a random arrangement by free radical polymerization. . This provides high seal adhesion, solvent selectivity, and coating properties.

In order to achieve both the coating properties, seal adhesion, film strength, and good weak anchoring properties of the weak anchoring alignment film, the introduction ratio of the branch polymer and the trunk polymer is also an important factor. For example, branch polymers play an important role in weak anchoring properties, and if their introduction ratio increases, the strength of the film will be impaired and heat curing will be inhibited, so it is necessary to consider the appropriate amount of introduction. be. On the other hand, the introduction amount and molecular weight of the backbone polymer do not affect the weak anchoring properties (they are small), so in order to achieve both of the above-mentioned properties, the monomer expressed by formula (6) used to synthesize the backbone polymer must be It is preferable that the ratio of the number of molecules (introduction ratio) of the macromonomer represented by formula (7) used in the synthesis of the branched polymer to the number of molecules is small. The preferred introduction ratio (macromonomer represented by formula (7)/monomer represented by formula (6)) is 0.1/99.9 to 50/50 (mol/mol), more preferably It is 0.2/99.8 to 30/70 (mol/mol).

As a monomer constituting the block segment (B) in the polymer (α) or the backbone polymer in the polymer (β), the structure of the compound represented by the formula (6) is particularly preferable, but it is not limited to the following compounds. do not.

(In formulas (B-1) to (B-17), Me represents a methyl group, and Et represents an ethyl group.)

The liquid crystal aligning agent of the present invention contains at least one specific solvent as a solvent component. As the organic solvent used for the liquid crystal aligning agent, other solvents than the above-mentioned specific solvents may be used. Examples of the other solvents include N,N-dimethylformamide, N,N-dimethylacetamide, N-methylformamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 2-pyrrolidone, 1, 3-dimethyl-2-imidazolidinone, N-methylcaprolactam, dimethylsulfoxide, tetramethylurea, pyridine, dimethylsulfone, hexamethylphosphoramide, γ-butyrolactone, isopropyl alcohol, methoxymethylpentanol, dipentene, ethyl amyl ketone , methyl nonyl ketone, methyl ethyl ketone, methyl isoamyl ketone, methyl isopropyl ketone, methyl cellosolve, ethyl cellosolve, methyl cellosolve acetate, butyl cellosolve acetate, ethyl cellosolve acetate, butyl carbitol, ethyl carbitol, ethylene glycol, ethylene glycol monoacetate, ethylene glycol Monoisopropyl ether, ethylene glycol monobutyl ether, propylene glycol, propylene glycol monoacetate, propylene glycol monomethyl ether, propylene glycol monobutyl ether, propylene glycol-tert-butyl ether, propylene glycol monomethyl ether acetate, diethylene glycol, diethylene glycol monoacetate, diethylene glycol dimethyl ether, diethylene glycol Diethyl ether, dipropylene glycol monoacetate monomethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monoacetate monoethyl ether, dipropylene glycol monopropyl ether, dipropylene glycol monoacetate monopropyl ether, 3 -Methyl-3-methoxybutyl acetate, tripropylene glycol methyl ether, 3-methyl-3-methoxybutanol, diisopropyl ether, ethyl isobutyl ether, diisobutylene, amyl acetate, butyl butyrate, butyl ether, diisobutyl ketone, methylcyclohexene, Propyl ether, dihexyl ether, dioxane, n-hexane, n-pentane, n-octane, diethyl ether, cyclohexanone, ethylene carbonate, propylene carbonate, methyl lactate, ethyl lactate, methyl acetate, ethyl acetate, n-butyl acetate, acetic acid Propylene glycol monoethyl ether, methyl 3-methoxypropionate, methylethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, 3-ethoxypropionic acid, 3-methoxypropionic acid, propyl 3-methoxypropionate, 3-methoxy Butyl propionate, diglyme, 4-hydroxy-4-methyl-2-pentanone, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, 1-butoxy-2-propanol, 1-phenoxy-2-propanol, Propylene glycol diacetate, propylene glycol-1-monomethyl ether-2-acetate, propylene glycol-1-monoethyl ether-2-acetate, dipropylene glycol, 2-(2-ethoxypropoxy)propanol, 2-ethyl-1, 3-hexanediol, ethylene glycol, propylene glycol (1,2-propanediol), 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 2,3-butanediol, 1,4 -butanediol, 1,2-pentanediol, 1,3-pentanediol, 1,4-pentanediol, 1,5-pentanediol, 2-methyl-2,4-pentanediol, 1,2-hexanediol, 1,3-hexanediol, 1,4-hexanediol, 1,5-hexanediol, 1,6-hexanediol, 2,3-hexanediol, 2,4-hexanediol, 2,5-hexanediol, 3 , 5-hexanediol, 1,2-heptane glycol, 1,3-heptanediol, 1,4-heptanediol, 1,5-heptanediol, 1,6-heptanediol, 1,7-heptanediol, 1, 2-octanediol, 1,4-octanediol, 1,8-octanediol, 1,2-nonanediol, 1,3-nonanediol, 1,5-nonanediol, 1,6-nonanediol, 1,9 -nonanediol, 1,2-decanediol, 1,5-decanediol, 1,8-decanediol, 1,10-decanediol, 1,2-cyclohexanediol, 1,3-cyclohexanediol, 1,4- Cyclohexanediol, diethylene glycol, dipropylene glycol, dibutylene glycol, glycerol, 2-ethyl-1-hexanol, methyl pyruvate, ethyl pyruvate, propyl pyruvate, butyl pyruvate, pentyl pyruvate, hexyl pyruvate, pyruvate- 2-ethylhexyl, methyl acetoacetate, ethyl acetoacetate, propyl acetoacetate, butyl acetoacetate, pentyl acetoacetate, hexyl acetoacetate, 2-ethylhexyl acetoacetate, methyl levulinate, ethyl levulinate, propyl levulinate, butyl levulinate , pentyl levulinate, hexyl levulinate, 2-ethylhexyl levulinate, dimethyl malonate, dimethyl succinate, dimethyl glutarate, dimethyl adipate, dimethyl phthalate, dimethyl maleate, diethyl malonate, diethyl succinate, glutaric acid Diethyl, diethyl adipate, diethyl phthalate, diethyl maleate, dipropyl malonate, dipropyl succinate, dipropyl glutarate, dipropyl adipate, dipropyl phthalate, dipropyl maleate, dibutyl malonate, dibutyl succinate, dibutyl glutarate, Dibutyl adipate, dibutyl phthalate, dibutyl maleate, dipentyl malonate, dipentyl succinate, dipentyl glutarate, dipentyl adipate, dipentyl phthalate, dipentyl maleate, dihexyl malonate, dihexyl succinate, dihexyl glutarate, adipic acid Dihexyl, dihexyl phthalate, dihexyl maleate, di-2-ethylhexyl malonate, 2-ethylhexyl succinate, 2-ethylhexyl glutarate, 2-ethylhexyl adipate, 2-ethylhexyl phthalate, 2-maleate -Ethylhexyl and the like, but other solvents may also be used as long as they can be used as solvents. These organic solvents may be used alone or in combination.
The content of the organic solvent other than the specific solvent in the liquid crystal aligning agent is not particularly limited, but is preferably 10 to 90% by mass, more preferably 20 to 70% by mass of the total solvent contained in the liquid crystal aligning agent. be.

Furthermore, it is preferable to use a solvent that improves the uniformity and smoothness of the coating film by mixing it with an organic solvent that has high solubility.

Examples of solvents that improve the uniformity and smoothness of the coating film include isopropyl alcohol, methoxymethylpentanol, methyl cellosolve, ethyl cellosolve, methyl cellosolve acetate, butyl cellosolve acetate, ethyl cellosolve acetate, butyl carbitol, ethyl carbitol, Ethyl carbitol acetate, ethylene glycol, ethylene glycol monoacetate, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether (butyl cellosolve), propylene glycol, propylene glycol monoacetate, propylene glycol monomethyl ether, propylene glycol monobutyl ether, propylene glycol -tert- Butyl ether, diethylene glycol, diethylene glycol monoacetate, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, dipropylene glycol monoacetate monomethyl ether, dipropylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, dipropylene glycol monoethyl ether, dipropylene glycol monoacetate monoethyl ether , dipropylene glycol monopropyl ether, dipropylene glycol monoacetate monopropyl ether, 3-methyl-3-methoxybutyl acetate, tripropylene glycol methyl ether, 3-methyl-3-methoxybutanol, diisopropyl ether, ethyl isobutyl ether, Isobutylene, amyl acetate, butyl butyrate, butyl ether, diisobutyl ketone, methylcyclohexene, propyl ether, dihexyl ether, n-hexane, n-pentane, n-octane, diethyl ether, methyl lactate, ethyl lactate, n-propyl lactate , n-butyl lactate, isoamyl lactate, methyl acetate, ethyl acetate, n-butyl acetate, propylene glycol monoethyl acetate, methyl 3-methoxypropionate, methyl ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, 3 -Ethoxypropionic acid, 3-methoxypropionic acid, propyl 3-methoxypropionate, butyl 3-methoxypropionate, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, 1-butoxy-2-propanol, 1 -Phenoxy-2-propanol, propylene glycol diacetate, propylene glycol-1-monomethyl ether-2-acetate, propylene glycol-1-monoethyl ether-2-acetate, dipropylene glycol, 2-(2-ethoxypropoxy)propanol , 2-ethyl-1-hexanol, methyl pyruvate, ethyl pyruvate, propyl pyruvate, butyl pyruvate, pentyl pyruvate, hexyl pyruvate, 2-ethylhexyl pyruvate, methyl acetoacetate, ethyl acetoacetate, acetoacetic acid Propyl, butyl acetoacetate, pentyl acetoacetate, hexyl acetoacetate, 2-ethylhexyl acetoacetate, methyl levulinate, ethyl levulinate, propyl levulinate, butyl levulinate, pentyl levulinate, hexyl levulinate, 2-levulinate Ethylhexyl, dimethyl malonate, dimethyl succinate, dimethyl glutarate, dimethyl adipate, dimethyl phthalate, dimethyl maleate, diethyl malonate, diethyl succinate, diethyl glutarate, diethyl adipate, diethyl phthalate, diethyl maleate, Dipropyl malonate, dipropyl succinate, dipropyl glutarate, dipropyl adipate, dipropyl phthalate, dipropyl maleate, dibutyl malonate, dibutyl succinate, dibutyl glutarate, dibutyl adipate, dibutyl phthalate, dibutyl maleate, malonic acid Dipentyl, Dipentyl succinate, Dipentyl glutarate, Dipentyl adipate, Dipentyl phthalate, Dipentyl maleate, Dihexyl malonate, Dihexyl succinate, Dihexyl glutarate, Dihexyl adipate, Dihexyl phthalate, Dihexyl maleate, Dipentyl malonate. Examples include 2-ethylhexyl, 2-ethylhexyl succinate, 2-ethylhexyl glutarate, 2-ethylhexyl adipate, 2-ethylhexyl phthalate, and 2-ethylhexyl maleate. A plurality of types of these solvents may be mixed. When using these solvents, it is preferably 5 to 60% by mass, more preferably 10 to 40% by mass of the total solvent contained in the liquid crystal aligning agent.

The weakly anchoring liquid crystal aligning agent of the present invention may contain components other than those mentioned above. Examples include compounds that improve film thickness uniformity and surface smoothness when the composition contained in the weakly anchoring liquid crystal aligning agent is applied, and compounds that improve the adhesion between the composition contained in the weakly anchoring liquid crystal aligning agent and the substrate. Examples include compounds that further improve the film strength of the composition contained in the weak anchoring liquid crystal aligning agent.

Examples of compounds that improve film thickness uniformity and surface smoothness include fluorosurfactants, silicone surfactants, and nonionic surfactants. More specifically, for example, FTOP EF301, EF303, EF352 (manufactured by Mitsubishi Materials Electronic Chemicals), Megafac F171, F173, R-30 (manufactured by DIC), Florado FC430, FC431 (manufactured by 3M), Asahi Examples include Guard AG710 (manufactured by AGC), Surflon S-382, SC101, SC102, SC103, SC104, SC105, and SC106 (manufactured by AGC Seimi Chemical).
When using these surfactants, the usage ratio is preferably 0.01 to 2 parts by mass based on 100 parts by mass of the total amount of polymers contained in the composition contained in the weakly anchoring liquid crystal aligning agent. , more preferably 0.01 to 1 part by mass.

Specific examples of compounds that improve the adhesion between the composition contained in the weak anchoring liquid crystal aligning agent and the substrate include functional silane-containing compounds and epoxy group-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-triethoxysilyl)propyltriethylenetetramine, N-(3-trimethoxysilyl)propyltriethylenetetramine, 10-trimethoxysilyl-1,4,7- Triazadecane, 10-triethoxysilyl-1,4,7-triazadecane, 9-trimethoxysilyl-3,6-diazanonyl acetate, 9-triethoxysilyl-3,6-diazanonyl acetate, N-benzyl- 3-aminopropyltrimethoxysilane, N-benzyl-3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltriethoxysilane, ethylene glycol diglycidyl ether, Polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerin diglycidyl ether, 2,2 -dibromoneopentyl glycol diglycidyl ether, 1,3,5,6-tetraglycidyl-2,4-hexanediol, N,N,N',N'-tetraglycidyl-m-xylylenediamine, 1,3- Bis(N,N-diglycidylaminomethyl)cyclohexane, N,N,N',N'-tetraglycidyl-4,4'-diaminodiphenylmethane, 3-(N-allyl-N-glycidyl)aminopropyltrimethoxysilane , 3-(N,N-diglycidyl)aminopropyltrimethoxysilane and the like.

In addition, in order to further increase the film strength of the weak anchoring liquid crystal alignment film, phenolic compounds such as 2,2-bis(4-hydroxy-3,5-dihydroxymethylphenyl)propane and tetra(methoxymethyl)bisphenol are added. You may. When using these compounds, it is preferably 0.1 to 30 parts by mass, more preferably 1 to 20 parts by mass, based on 100 parts by mass of the total amount of polymers contained in the weak anchoring liquid crystal aligning agent. It is.
Furthermore, in addition to the above, the composition contained in the weak anchoring liquid crystal alignment agent may have electrical properties such as dielectric constant and conductivity of the weak anchoring liquid crystal alignment film, as long as the effects of the present invention are not impaired. A dielectric or conductive substance for the purpose of changing may be added.

Furthermore, a thickener may be added to increase the viscosity of the weakly anchored liquid crystal alignment film. Examples of the thickener include a polymer having a structural unit represented by the following formula (8) (hereinafter sometimes referred to as "polymer RSM").
The present applicant has proposed that a weakly anchoring liquid crystal aligning agent containing a polymer having a structural unit represented by the following formula (8) can be easily produced, has high solvent selectivity, and can be used for varnishes in the high to low viscosity range. We have discovered that it is a weakly anchoring liquid crystal aligning agent that can be controlled up to The contents are incorporated herein to the same extent as if set forth in their entirety.)

(Polymer RSM)
By adding a small amount of "polymer RSM", it becomes possible to easily increase the viscosity of a coating varnish (for example, a liquid crystal aligning agent). Therefore, the viscosity of the varnish can be controlled by adjusting the amount of polymer RSM added. In addition, polymer RSM has good solvent selectivity, and the inclusion of polymer RSM imparts good coating properties to the coating varnish, so mixing it with materials with poor coating properties improves the overall quality of the material. It is possible to improve the coating properties.

The polymer RSM is a polymer having a structural unit represented by the following formula (8).

(In formula (8), R ₁ and R ₂ each independently represent a hydrogen atom, a fluorine atom, or an alkyl group having 1 to 3 carbon atoms, and X represents -O-R _a , -N(R _a ) (R _b ), or -S-R _a (R _a represents a monovalent organic group, and R _b represents a monovalent group).

It is preferable that X in the formula (8) is a group selected from the following structures.

(In the formula, R ₁ and R ₂ each independently represent a hydrogen atom or a straight chain or branched alkyl group having 1 to 12 carbon atoms, and R ₃ represents a straight chain or branched alkylene group having 1 to 12 carbon atoms, m and n each independently represent an integer from 1 to 5. When multiple _{R 1} , R ₂ or R ₃ exist, they may be the same or different. * represents a binding site.)

The polymer (RSM) can be obtained, for example, by reacting a polymer having a structural unit containing a maleic anhydride skeleton (maleic anhydride polymer) with one or more nucleophiles. In this reaction, a nucleophile is added to the carbonyl group of the maleic anhydride skeleton, and a ring-opening reaction proceeds to obtain the structural unit represented by the formula (8).

The polymer having a structural unit containing a maleic anhydride skeleton is preferably a maleic anhydride polymer (homopolymer or copolymer) containing a structural unit represented by the following formula (8') (hereinafter also referred to as structural unit (8')), and more preferably a maleic anhydride copolymer (hereinafter also referred to as copolymer (mRSM)) containing the structural unit (8') and a structural unit represented by the following formula (9) (hereinafter also referred to as structural unit (9)).

(In formula (8'), R ₁ and R ₂ each independently represent a hydrogen atom, a fluorine atom, or an alkyl group having 1 to 3 carbon atoms.
In formula (9), R ₃ , R ₄ , R ₅ and R ₆ are each independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, -OC(=O)-R (R is a carbon number ), -C(=O)-OR (R represents an alkyl group having 1 to 6 carbon atoms), -OR (R represents an alkyl group having 1 to 6 carbon atoms) ), or represents a phenyl group. )

That is, the polymer (RSM) preferably has a structural unit represented by formula (8) and a structural unit represented by formula (9).

The structural unit (9) is, for example, ethylene, propylene, n-butene, isobutylene, n-pentene, n-hexene, alkyl acrylates and methacrylates having 1 to 20 carbon atoms, vinyl acetate, methyl vinyl ether, and the following formula: It is a structural unit derived from a monomer selected from styrenic compounds represented by (10).

(In formula (10), R is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and the benzene ring may be optionally substituted with an alkyl group having 1 to 4 carbon atoms or a hydroxyl group.)

As the alkyl acrylates and methacrylates having 1 to 20 carbon atoms, alkyl acrylates and methacrylates having 1 to 4 carbon atoms are preferred. Note that the term "alkyl acrylates having 1 to 20 carbon atoms" has the same meaning as alkyl esters having 1 to 20 carbon atoms of acrylic acid.
Preferred examples of the alkyl acrylates having 1 to 4 carbon atoms include methyl acrylate, ethyl acrylate, isopropyl acrylate, n-propyl acrylate, n-butyl acrylate, and mixtures thereof.
Preferred examples of alkyl methacrylates having 1 to 4 carbon atoms include methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, n-propyl methacrylate, n-butyl methacrylate, and mixtures thereof. A mixture of alkyl methacrylates having 1 to 4 carbon atoms and alkyl acrylates having 1 to 4 carbon atoms may be used.
Preferred examples of styrenic compounds include styrene, α-methylstyrene, p-methylstyrene, tert-butylstyrene, and mixtures thereof.
Mixtures with styrenic compounds, alkyl acrylates having 1 to 20 carbon atoms and/or methacrylates may be used.
Among these, isobutylene is particularly preferably used, or a mixture of isobutylene, 1-butene, and 2-butene is preferably used.

The structural unit (8') is preferably 10 to 50 mol%, particularly preferably 30 to 50 mol% of all structural units constituting the copolymer (mRSM).

The weight average molecular weight of the copolymer (mRSM) is preferably 10,000 to 1,000,000, more preferably 50,000 to 500,000.

As the copolymer (mRSM), commercially available products can be used, such as ISOBAM-6, ISOBAM-10, and ISOBAM-18 (all manufactured by Kuraray Co., Ltd.).

Examples of the above-mentioned nucleophile include the compounds shown below.

(In the formula, R ₁ and R ₂ each independently represent a hydrogen atom or a straight chain or branched alkyl group having 1 to 12 carbon atoms, and R ₃ represents a straight chain or branched alkylene group having 1 to 12 carbon atoms, (m and n each independently represent an integer of 1 to 5. If multiple R ₁ , R ₂ or R ₃ exist, they may be the same or different.)

The reaction between the polymer having a structural unit containing a maleic anhydride skeleton and the nucleophile is preferably carried out in an organic solvent. Examples of the organic solvent used include alcohols, ethers, ketones, amides, esters, and hydrocarbon compounds. In the above reaction, the reaction temperature is preferably 20 to 200°C, more preferably 40 to 150°C. Further, the reaction time is preferably 1 to 168 hours, more preferably 8 to 72 hours.
The reaction solution obtained by dissolving the polymer can be used as it is, or the reaction solution can be poured into a large amount of poor solvent and the resulting precipitate can be dried under reduced pressure, or the reaction solution can be distilled off under reduced pressure using an evaporator. After isolating the polymer contained in the reaction solution using a known isolation method such as a method such as the method of

The reaction amount of the nucleophile is preferably 0.5 to 10 equivalents, more preferably 1 to 5 equivalents, relative to the anhydride group possessed by the structural unit (8').

When carrying out a ring-opening reaction of a cyclic acid anhydride group, it is preferable to use a small amount of a catalyst to promote the reaction. Examples of the catalyst include triethylamine, N,N,N',N'-tetramethylethylenediamine, pyridine, 4-dimethylaminopyridine, imidazole, 2-methylimidazole, 1,8-diazabicyclo[5.4.0]-7 -Undecene, 1,5-diazabicyclo[4.3.0]-5-nonene, 1,4-diazabicyclo[2.2.2]octane, 1,5,7-triazabicyclo[4.4.0] Examples include deca-5-ene and 1,8-bis(dimethylamino)naphthalene, and the catalyst used is usually 0.000001 to 0.1 mole part, preferably 0.000001 to 0.1 mole part, per mole part of the cyclic acid anhydride group. It is 0.00001 to 0.01 mole part.

The polymer (RSM) of the present invention may further have structural units other than the structural units represented by formulas (8) and (9) above. Structural units other than those represented by formulas (8) and (9) include acrylic acid, methacrylic acid, α-ethyl acrylic acid, 2-hydroxyethyl (meth)acrylic acid, 4-vinylbenzoic acid, Carboxy group-containing compounds such as maleic acid; hydroxyl group-containing compounds such as 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, N-methylol (meth)acrylamide; Compounds containing long-chain alkyl groups such as octyl acrylate, isodecyl acrylate, lauryl acrylate, decyl methacrylate, and stearyl acrylate; compounds containing alicyclic groups such as cyclohexyl (meth)acrylate; 2-phenoxyethyl acrylate, ethoxylated nonyl phenyl acrylate, etc. Benzene ring-containing compounds; oxiranyl group-containing compounds such as glycidyl (meth)acrylate, methylglycidyl (meth)acrylate, 4-(glycidyloxy)butyl (meth)acrylate, 2-methacryloyloxyethyl isocyanate (Karens MOI, manufactured by Showa Denko) ), 2-[(3,5-dimethylpyrazoyl)carbonylamino]ethyl methacrylate (Karens MOI-BP, manufactured by Showa Denko), and other compounds having an isocyanate group or a protected isocyanate group; tetrahydropyranyl, such as tetrahydrofurfuryl methacrylate Examples include structural units derived from compounds having groups.

The polymer (RSM) may contain one type of structural unit represented by formula (9) alone, or may contain two or more types of structural units. The content of the structural unit represented by formula (9) is preferably 50 to 90 mol%, more preferably 50 to 70 mol%, based on the total structural units of the polymer (RSM).

The content of the polymer (RSM) used in the present invention is preferably 1 to 99% by mass, more preferably 5 to 70% by mass, and 10 to 99% by mass, based on the total amount of polymer components contained in the weakly anchoring liquid crystal aligning agent. More preferably 50% by mass. The polymer (RSM) can be used alone or in combination of two or more.

(Strong anchoring alignment film)
It is necessary to provide a strong anchoring horizontal alignment film on a substrate opposite to the substrate provided with the weak anchoring alignment film. The strong anchoring horizontal alignment film described here is a liquid crystal alignment film that can uniformly align liquid crystals in the horizontal direction and has a sufficiently strong force to maintain the aligned liquid crystals, that is, interfacial anchoring energy.

The strong anchoring horizontal alignment film is made by aligning polyamic acid, polyimide, polyamic acid ester, polyamide, polyester, polyacrylate, etc. used in known liquid crystal alignment agents in a uniaxial direction by rubbing or photo alignment. It can be obtained by doing.

A strong anchoring horizontal alignment film can be obtained, for example, by a combination of monomers used in known liquid crystal alignment agents.

(Weak anchoring alignment film and strong anchoring alignment film)
The weakly anchoring alignment film of the present invention can be obtained by using the weakly anchoring liquid crystal alignment agent described above. For example, a cured film obtained by applying the weakly anchoring liquid crystal aligning agent used in the present invention to a substrate, followed by drying and baking, can also be used as it is as the weakly anchoring alignment film. In addition, this cured film can be aligned by rubbing, irradiating with polarized light or light of a specific wavelength, or ion beam treatment, and it is also possible to irradiate UV to the liquid crystal display element after filling the liquid crystal. be.

Similarly, a strong anchoring alignment film can be obtained by applying a strong anchoring liquid crystal aligning agent to a substrate, followed by drying and baking, and then subjecting a cured film to alignment treatment.

In the present invention, when a substrate on which a weak anchoring film is formed is a first substrate and a substrate on which a strong anchoring film is formed is a second substrate, the first substrate is a substrate having a comb-teeth electrode, and the second substrate is a substrate on which a weak anchoring film is formed. The substrate may be a counter substrate. Further, in the present invention, the second substrate may be a substrate having comb-teeth electrodes, and the first substrate may be a counter substrate.

The substrate on which each liquid crystal alignment film is applied is not particularly limited as long as it is a highly transparent substrate, but a substrate on which a transparent electrode for driving liquid crystal is formed is preferable.

Specific examples include glass plates, polycarbonates, poly(meth)acrylates, polyethersulfones, polyarylates, polyurethanes, polysulfones, polyethers, polyetherketones, trimethylpentene, polyolefins, polyethylene terephthalate, (meth)acrylonitrile, and Examples include substrates in which transparent electrodes are formed on plastic plates such as cellulose acetate, cellulose diacetate, and cellulose acetate butyrate.

Substrates that can be used for IPS type liquid crystal display elements include electrode patterns such as standard IPS comb electrodes and PSA (Polymer-Stabilized Alignment) fishbone electrodes, as well as protrusion patterns such as MVA (Multi-domain Vertical Alignment). can.

Furthermore, in a high-performance element such as a TFT (Thin-Film-Transistor) type element, an element such as a transistor is formed between an electrode for driving a liquid crystal and a substrate.

When a transmissive type liquid crystal display element is intended, it is common to use a substrate like the one described above, but when a reflective type liquid crystal display element is intended, silicon is used for only one side of the substrate. Opaque substrates such as wafers can also be used. In this case, a material such as aluminum that reflects light can also be used for the electrodes formed on the substrate.

Methods for applying liquid crystal aligning agents include spin coating, printing, inkjet, spraying, and roll coating, but transfer printing is widely used industrially due to its productivity. It is also suitably used in the present invention.

The drying process after applying the liquid crystal alignment agent is not necessarily required, but if the time from application to firing is not constant for each substrate, or if the board is not fired immediately after application, a drying process is included. is preferable. The drying method is not particularly limited as long as the solvent is removed to such an extent that the shape of the coating film is not deformed due to transportation of the substrate or the like. Preferred conditions for the drying step include drying on a hot plate at a temperature of 40 to 150°C, more preferably 60 to 100°C, for 0.5 to 30 minutes, more preferably 1 to 5 minutes.
Preferred conditions for the firing step include a method of firing on a hot plate or thermal circulation oven at a temperature of 80 to 250°C, more preferably 100 to 230°C, for 1 to 120 minutes, more preferably 5 to 30 minutes.

The thickness of this cured film can be selected as required, but it is preferably 5 nm or more, more preferably 10 nm or more, since this improves the reliability of the liquid crystal display element. Further, it is preferable that the thickness of the cured film is preferably 300 nm or less, more preferably 150 nm or less, since the power consumption of the liquid crystal display element does not become extremely large.

As described above, a first substrate or a second substrate having a weak anchoring alignment film and a second substrate or first substrate having a strong anchoring alignment film can be obtained. Examples of methods for performing the uniaxial alignment treatment include a photoalignment method, an oblique evaporation method, rubbing, and a uniaxial alignment treatment using a magnetic field.

When performing orientation treatment by rubbing in one direction, for example, while rotating a rubbing roller around which a rubbing cloth is wound, the substrate is moved so that the rubbing cloth and the film come into contact with each other. When using a photo-alignment method, the alignment process can be performed by irradiating the entire surface of the film with polarized UV light of a specific wavelength and heating if necessary.

In the case of a substrate on which comb-teeth electrodes are formed, the direction is selected depending on the electrical properties of the liquid crystal, but when using a liquid crystal with positive dielectric anisotropy, the rubbing direction is the direction in which the comb-teeth electrodes extend. It is preferable that the direction is approximately the same as that of .

[Liquid crystal cell]
The liquid crystal cell of the present invention has a substrate (for example, a first substrate) having a weakly anchoring alignment film obtained by using the liquid crystal aligning agent of the present invention by the above method, and a known strong anchoring liquid crystal aligning film. By arranging a substrate (for example, a second substrate) so that a weak anchoring alignment film and a strong anchoring alignment film face each other, sandwiching a spacer, fixing with a sealant, and sealing by injecting liquid crystal. can get. At this time, the size of the spacer used is usually 1 to 30 μm, preferably 2 to 10 μm. In addition, by making the rubbing direction of the first substrate parallel to the rubbing direction of the second substrate, it can be used for the IPS method or FFS method, and if the rubbing directions are arranged orthogonally, it can be used for the TN method. can be used.
Note that an IPS substrate, which is a comb-teeth electrode substrate used in the IPS method, includes a base material, a plurality of linear electrodes formed on the base material and arranged in a comb-teeth shape, and a plurality of linear electrodes formed on the base material. It has a liquid crystal alignment film formed so as to cover the liquid crystal alignment film.
The FFS substrate, which is a comb-teeth electrode substrate used in the FFS method, consists of a base material, a surface electrode formed on the base material, an insulating film formed on the surface electrode, and an insulating film formed on the insulating film. , has a plurality of linear electrodes arranged in a comb-teeth shape, and a liquid crystal alignment film formed on an insulating film so as to cover the linear electrodes.

(Liquid crystal display element)
A liquid crystal display element includes, for example, a first substrate, a second substrate disposed opposite to the first substrate, and liquid crystal filled between the first substrate and the second substrate. The liquid crystal display element comprises a first substrate or a second substrate coated with a weak anchoring liquid crystal alignment agent of the present invention and provided with a weak anchoring alignment film, and a second substrate or a second substrate provided with a strong anchoring horizontal alignment film. Fabricated using a first substrate.
The liquid crystal display element can be made into a reflective liquid crystal display element by, for example, providing a reflective electrode, a transparent electrode, a λ/4 plate, a polarizing film, a color filter layer, etc. in a liquid crystal cell according to a conventional method as required. Furthermore, a transmissive liquid crystal display element can be obtained by providing a backlight, a polarizing plate, a λ/4 plate, a transparent electrode, a polarizing film, a color filter layer, etc. in a conventional manner to the liquid crystal cell as necessary.

FIG. 1 is a schematic cross-sectional view showing an example of a horizontal electric field liquid crystal display element of the present invention, and is an example of an IPS type liquid crystal display element.
In the horizontal electric field liquid crystal display element 1 illustrated in FIG. 1, a liquid crystal 3 is sandwiched between a comb-teeth electrode substrate 2 having a liquid crystal alignment film 2c and a counter substrate 4 having a liquid crystal alignment film 4a. The comb-teeth electrode substrate 2 includes a base material 2a, a plurality of linear electrodes 2b formed on the base material 2a and arranged in a comb-teeth shape, and a plurality of linear electrodes 2b formed on the base material 2a so as to cover the linear electrodes 2b. It has a liquid crystal alignment film 2c. The counter substrate 4 has a base material 4b and a weak anchoring liquid crystal alignment film or a strong anchoring horizontal alignment film (liquid crystal alignment film 4a) formed on the base material 4b. The liquid crystal alignment film 2c is, for example, a weak anchoring alignment film or a strong anchoring horizontal alignment film of the present invention. The liquid crystal alignment films provided on the opposing substrates are each made of a combination of a strong anchoring alignment film and a weak anchoring liquid crystal alignment film.
In this horizontal electric field liquid crystal display element 1, when a voltage is applied to the linear electrodes 2b, an electric field is generated between the linear electrodes 2b as shown by lines of electric force L.

FIG. 2 is a schematic cross-sectional view showing another example of the horizontal field liquid crystal display element of the present invention, and is an example of an FFS type liquid crystal display element.
In the horizontal electric field liquid crystal display element 1 illustrated in FIG. 2, a liquid crystal 3 is sandwiched between a comb-teeth electrode substrate 2 having a liquid crystal alignment film 2h and a counter substrate 4 having a liquid crystal alignment film 4a. The comb-teeth electrode substrate 2 is formed on a base material 2d, a surface electrode 2e formed on the base material 2d, an insulating film 2f formed on the surface electrode 2e, and an insulating film 2f, and has a comb-like shape. It has a plurality of arranged linear electrodes 2g and a liquid crystal alignment film 2h formed on an insulating film 2f so as to cover the linear electrodes 2g. The counter substrate 4 has a base material 4b and a liquid crystal alignment film 4a formed on the base material 4b. The liquid crystal alignment film 4a is similar to the liquid crystal alignment film 4a in FIG. 1 described above. The liquid crystal alignment film 2h is similar to the liquid crystal alignment film 2c in FIG. 1 described above.
In this horizontal electric field liquid crystal display element 1, when a voltage is applied to the plane electrode 2e and the linear electrode 2g, an electric field is generated between the plane electrode 2e and the linear electrode 2g as shown by lines of electric force L.

The present invention will be specifically explained below with reference to Examples, but the present invention should not be construed as being limited to these Examples. The abbreviations of the compounds and the measurement methods for each property are as follows.

((Component A) Component compatible with liquid crystal)

((Component B) A component that is insoluble in liquid crystal or becomes insoluble upon firing)

Me represents a methyl group, and Et represents an ethyl group.

(RAFT agent (control agent))

(Chain transfer agent)

(Polymerization initiator)

VA-086 manufactured by Fuji Film Wako Pure Chemical Industries, Ltd. was used.

(Raw material for polymer (thickener))
ISOBAM-06: Poly(isobutylene-o-maleic anhydride) (weight average molecular weight 80,000-90,000, manufactured by Kuraray)
ISOBAM-10: Poly(isobutylene-o-maleic anhydride) (weight average molecular weight 160,000-170,000, manufactured by Kuraray)
ISOBAM-18: Poly(isobutylene-o-maleic anhydride) (weight average molecular weight 300,000-350,000, manufactured by Kuraray)

(nucleophile)

(catalyst)
DMAP: 4-dimethylaminopyridine

(solvent)
THF: Tetrahydrofuran NMP: N-methyl-2-pyrrolidone PGMEA: Propylene glycol monomethyl ether acetate DEAc: N,N-diethylacetamide DPAc: N,N-dipropylacetamide 3MMP: 3-methoxy-N,N-dimethylpropanamide DEPA : N,N-diethylpropionamide DEF: diethylformamide 2MEA: 2-methoxy-N,N-diethylacetamide 3MEP: 3-methoxy-N,N-diethylpropanamide 4OEP: 4-oxo-N,N-diethylpentanamide ECHC: N,N-diethylcyclohexanecarboxamide DBF: N,N-dibutylformamide DMAc: Dimethylacetamide DMF: Dimethylformamide PB: Propylene glycol monobutyl ether BCS: Ethylene glycol monobutyl ether BCAc: Ethylene glycol monobutyl ether acetate Among the above solvents , DEAc, DPAc, 3MMP, DEPA, DEF, 2MEA, 3MEP, 4OEP, ECHC, and DBF correspond to specific solvents.

(Viscosity measurement)
The viscosity of polyamic acid solutions, etc. was measured using an E-type viscometer TVE-22H (manufactured by Toki Sangyo Co., Ltd.) using a sample volume of 1.1 mL (milliliter), a cone rotor TE-1 (1° 34', R24), and a temperature of 25 mm. Measured at °C.

(Measurement of molecular weight)
The molecular weight of the polymer was determined using a room temperature gel permeation chromatography (GPC) device (CBM-20A) (manufactured by Shimadzu Corporation) and a column (Shodex (registered trademark) KF-804L and KF-803L in series) (manufactured by Showa Denko). It was measured as follows.
Column temperature: 40℃
Eluent: Tetrahydrofuran Flow rate: 1.0 mL/min Standard sample for creating a calibration curve: Standard polystyrene (molecular weight: 197000, 55100, 12800, 3950, 1260) (manufactured by Tosoh Corporation)

<Synthesis of polymer composed of one block segment>
(Synthesis example 1-1)
A-1 (10.0 g, 70.3 mmol), R-3 (482 mg, 1.19 mmol), and AIBN (97.9 mg, 0.597 mmol) were placed in a 100 ml eggplant flask equipped with a stirrer and a nitrogen introduction tube. After weighing and adding THF (10.6 g), stirring at room temperature to dissolve, the system was purged with nitrogen, and heated and stirred in an oil bath set at 60° C. for 12 hours. After heating and stirring, the reaction solution was gently poured into the mixture while stirring methanol (50 g) to precipitate a solid, and the mixture was stirred for 30 minutes. This precipitate was separated by filtration, slurry washing was performed twice with methanol (50 g) for 30 minutes, and the solid was vacuum-dried at 50°C to obtain a polymer (p(A-1)). . Number average molecular weight (Mn): 7,500, weight average molecular weight (Mw): 8,200.

(Synthesis examples 1-2 to 1-22)
The type of raw material (monomer) used, the type of initiator, the type of control agent, the molar ratio of raw material and control agent used [(control agent/raw material) x 100] and the amount are shown in Table 1-1 or Table 1-2 below. Polymers (p(A-2)) to (p(A-2)) shown in Tables 1-1 and 1-2 below were prepared in the same manner as Synthesis Example 1-1 except for replacing them with those shown in Tables 1-1 and 1-2 below. 9/A-10)') was obtained.

<Synthesis of diblock polymer>
(Synthesis example 2-1)
p(A-1) (3.15 g, 0.443 mmol) obtained in Synthesis Example 1-1, B-3 (6.90 g, 27.5 mmol) in a 100 ml eggplant flask equipped with a stirrer and a nitrogen introduction tube. , and AIBN (36.4 mg, 0.222 mmol), added THF (10.1 g), stirred at room temperature to dissolve, then purged the system with nitrogen and heated in an oil bath set at 60°C for 12 hours. The mixture was heated and stirred. After heating and stirring, the reaction solution was gently poured into the mixture while stirring methanol (50 g) to precipitate a solid, and the mixture was stirred for 30 minutes. This precipitate was collected by filtration, slurry washing was performed twice with methanol (50 g) for 30 minutes, and the solid was vacuum-dried at 50° C. to obtain a copolymer (BC-1). Number average molecular weight: 20,500, weight average molecular weight: 22,600.

(Synthesis examples 2-2 to 2-38)
By carrying out the same procedure as Synthesis Example 2-1 except for replacing the types of raw materials (monomers) used with those shown in Table 2-1 or Table 2-2 below, Table 2-1 and Table 2- Polymers (BC-2) to (BC-38) shown in 2 were obtained.

<Synthesis of triblock polymer>
(Synthesis example 3-1)
BC-27 (5.23 g, 0.312 mmol) obtained in Synthesis Example 2-27, B-3 (4.90 g, 19.5 mmol) and AIBN were placed in a 100 ml eggplant flask equipped with a stirrer and a nitrogen inlet tube. (25.6 mg, 0.156 mmol) was added, THF (10.2 g) was added, and after stirring and dissolving at room temperature, the system was purged with nitrogen, and the mixture was heated and stirred in an oil bath set at 60°C for 12 hours. . After heating and stirring, the reaction solution was gently poured into the mixture while stirring methanol (50 g) to precipitate a solid, and the mixture was stirred for 30 minutes. This precipitate was collected by filtration, slurry washing was performed twice with methanol (50 g) for 30 minutes, and the solid was vacuum-dried at 50° C. to obtain a copolymer (BC-39). Number average molecular weight (Mn): 30,800, weight average molecular weight (Mw): 40,100.

(Synthesis examples 3-2 to 3-6)
The polymer shown in Table 3 below (BC-40 ) to (BC-44) were obtained.

<Synthesis of macromonomer>
(Synthesis example 4-1)
A-9 (10.00 g, 78.0 mmol), S-4 (0.216 g, 2.34 mmol) and AIBN (0.128 g, 0.780 mmol) were placed in a 100 ml eggplant flask equipped with a stirrer and a nitrogen inlet tube. ) was added, THF (10.3 g) was added, and the mixture was stirred and dissolved at room temperature. The system was purged with nitrogen, and the mixture was heated and stirred in an oil bath set at 60° C. for 12 hours. After heating and stirring, the reaction solution was gently poured into the mixture while stirring cold methanol (30.0 g) to precipitate a solid, and the mixture was stirred for 30 minutes. This precipitate was collected by filtration, slurry washing was performed twice for 30 minutes with cold methanol (30.0 g), and the solid was vacuum-dried at 50° C. to obtain a prepolymer. Mn: 6,000, Mw: 9,900.
In a 100 ml eggplant flask equipped with a stirrer and a nitrogen inlet tube, the prepolymer (10.0 g, 1.67 mmol) synthesized by the above method, B-6 (0.829 g, 5.83 mmol), and Hydroquinone (8. N,N-dimethyllaurylamine (2.0 mg) and Xylene (20.0 g) were added, stirred at room temperature to dissolve, and then heated and stirred in an oil bath set at 140° C. for 6 hours. After heating and stirring, the reaction solution was gently poured into the mixture while stirring methanol (50.0 g) to precipitate a solid, and the mixture was stirred for 30 minutes. This precipitate was separated by filtration, slurry washing was performed twice with methanol (50.0 g) for 30 minutes, and the solid was vacuum-dried at 50°C to obtain macromonomer p(A-9)''. Obtained. Mn: 6,100, Mw: 9,900.

(Synthesis examples 4-2 to 4-3)
Synthesis Example 4 except that the type of raw material (component A) used and the molar ratio of raw material and chain transfer agent (S-4) used [(raw material/S-4)] were changed as shown in Table 4. By carrying out the same procedure as in -1, macromonomers p(A-2)' and p(A-8)' shown in Table 4 below were obtained.

<Synthesis of graft copolymer>
(Synthesis example 5-1)
In a 100 ml eggplant flask equipped with a stirrer and a nitrogen inlet tube, p(A-9)'' (1.00 g, 0.167 mmol), B-1 (4.10 g, 16.5 mmol), and AIBN (82. After adding THF (7.77 g) and stirring at room temperature to dissolve it, the system was purged with nitrogen and heated and stirred in an oil bath set at 60° C. for 12 hours. After heating and stirring, the reaction solution was gently poured into the mixture while stirring methanol (40 g) to precipitate a solid, and the mixture was stirred for 30 minutes. This precipitate was collected by filtration, slurry washed again with methanol (40 g) for 30 minutes twice in total, and the solid was vacuum-dried at 50° C. to obtain a graft copolymer (GP-1). Number average molecular weight (Mn): 88,700, weight average molecular weight (Mw): 172,900.

(Synthesis examples 5-2 to 5-16)
The graft copolymer ( GP-2) to (GP-16) were obtained.

<Synthesis of polymer (thickener)>
(Synthesis example 6-1)
Weigh out ISOBAM-06 (10.0 g) and catalyst DMAP (0.100 g) into a 100 mL eggplant flask equipped with a stir bar and nitrogen inlet tube, and add nucleophile C-1 (40.0 g) and solvent. DEAc (40.0 g) was added, and the mixture was heated and stirred in an oil bath set at 80° C. for 24 hours. After heating and stirring, the nucleophile was distilled off under reduced pressure to obtain a polymer (RSM-1) (DEAc solution) with a viscosity of 32.8 mPa·s.

(Synthesis Examples 6-2 to 6-5)
By carrying out the same procedure as Synthesis Example 6-1 except that the types of raw materials and nucleophiles used were replaced with those shown in Table 6 below, the polymers (RSM-2) shown in Table 6 below were produced. (RSM-5) was obtained.

<Synthesis of bottle brush polymer>
(Synthesis example 7)
In a 100 ml eggplant flask equipped with a stirrer and a nitrogen inlet tube, add 2-((2-bromo-2-methylpropanoyl)oxy)ethyl methacrylate (5.00 g, 17.91 mmol), B-7 (0.078 g, 0 .60 mmol), R-3 (0.72 g, 1.80 mmol), and AIBN (0.09 g, 0.54 mmol) were added, THF (10.2 g) was added, and after stirring and dissolving at room temperature, the system The atmosphere inside the reactor was replaced with nitrogen, and the reactor was heated and stirred in an oil bath set at 60° C. for 12 hours. After heating and stirring, the reaction solution was gently poured into the mixture while stirring methanol (50.0 g) to precipitate a solid, and the mixture was stirred for 30 minutes. This precipitate was collected by filtration, slurry washing was performed twice for 30 minutes with methanol (50.0 g), and the solid was vacuum-dried at 50° C. to obtain a prepolymer. Mn: 45,300, Mw: 68,000.

In a 50 ml eggplant flask equipped with a stirrer and a nitrogen inlet tube, prepolymer (2.00 g, 0.03 mmol) synthesized by the above method, B-1 (0.43 g, 1.76 mmol), A-2 ( 3.00g, 17.62mmol), ethyl 2-bromoisobutyrate (0.012g, 0.06mmol), CuBr (0.03g, 0.19mmol), N,N,N',N'',N''-Pentamethyldiethylenetriamine e (0.043 g, 0.25 mmol) and Anisole (7.5 g) were added and dissolved by stirring at room temperature, followed by freezing and degassing three times, followed by heating and stirring in an oil bath set at 90° C. for 6 hours. After heating and stirring, the reaction solution was gently poured into the mixture while stirring methanol (50.0 g) to precipitate a solid, and the mixture was stirred for 30 minutes. This precipitate was collected by filtration, slurry washing was performed twice with methanol (50.0 g) for 30 minutes, and the solid was vacuum dried at 50°C to obtain bottle brush polymer (BBP-1). . Mn: 203,000, Mw: 384,000.

<Preparation of weak anchoring liquid crystal alignment agent>
(Example 1)
Weigh 0.6 g of BC-1 obtained in Synthesis Example 2-1 into a 10 mL vial equipped with a stirring bar, add 6.4 g of DEAc, and 3.0 g of PB, and stir at room temperature for 1 hour. In this way, a weakly anchoring liquid crystal aligning agent (WAS-1) was obtained.

(Examples 2 to 81, Comparative Examples 1 to 3)
By carrying out the same procedure as in Example 1 except that the type of polymer used and the solvent were replaced with those shown in Tables 7-1 to 7-3, the results shown in Tables 7-1 to 7-3 below were carried out. Weak anchoring liquid crystal alignment agents (WAS-2) to (WAS-84) were obtained. In addition, in the prepared liquid crystal aligning agent, if there was no precipitation or turbidity, it was rated as "good", and if either precipitation or turbidity occurred, it was rated as "poor". The results are shown in Table 7-1, Table 7-2 and Table 7-3.

"% by mass" in the table represents the mass ratio (%) of each component in the liquid crystal aligning agent.

<Evaluation of coating properties and film condition of liquid crystal aligning agent>
Regarding the liquid crystal alignment agent obtained above, flexographic printing (flexographic printing machine manufactured by Comratec, substrate: 100 mm x 100 mm Cr vapor-deposited substrate, printing speed: 20 m/min, printing pressure: 0.12 mm, printing tact: 50 sec, anilox Roll: #350-28μm, printing size: #600 mesh, 25%, 52°, 80mm x 80mm, leveling time: 40sec, drying conditions: 80℃・120sec, main firing conditions: 230℃・1200sec) The applicability of the material was evaluated. If the film is formed evenly without any defects, it is marked as "good." If there are minor coating defects, but the film is formed relatively evenly, it is marked as "slightly good." If there are many coating defects, it is marked as "poor." ”. The state of the film was also observed, and those with no haze or uneven film thickness were rated as "good." The results are shown in Table 8-1, Table 8-2 and Table 8-3.

It can be seen that when a specific solvent is used as the solvent used in the present invention, the stability of the solution is good, and a very good coating film can be obtained in the flexographic printing test. On the other hand, if NMP, DMAc, or DMF, which is commonly used to dissolve polyamic acid, soluble polyimide, or polyamic acid ester, is used without using a specific solvent, haze (white turbidity of the film) and uneven film thickness will occur. This is thought to be due to the large polarity difference between the solvent and the acrylic polymer that exhibits weak anchoring properties.

<Severe evaluation of coating properties and film condition of weak anchoring liquid crystal alignment agent>
Regarding the liquid crystal aligning agent obtained above, flexographic printing (flexographic printing machine manufactured by Comratec, substrate: 100 mm x 100 mm Cr vapor-deposited substrate, printing speed: 20 m/min, printing pressure: 0.12 mm, anilox roll: #350- 28 μm, printing size: #600 mesh, 25%, 52°, 80 mm x 80 mm, leveling time: 40 sec, main firing conditions: 230° C., 1200 sec), and the applicability was evaluated. The printing tact and drying conditions were as shown in Table 10, and the drying time was 120 seconds. If the film is formed evenly without any defects, it is marked as "good." If there are minor coating defects, but the film is formed relatively evenly, it is marked as "slightly good." If there are many coating defects, it is marked as "poor." ”. The state of the film was also observed, and those with no haze or uneven film thickness were rated as "good." The results are shown in Table 9.

The solvent used in the present invention shows good coating properties in flexographic printing tests using specific solvents, but slight defects may occur under conditions where the standing time is long or drying is extremely accelerated. Examples 163, 167). This is due to the fact that the specific solvent has a low boiling point. On the other hand, when a specific high boiling point solvent is used, good coating properties and good film conditions are exhibited even in the above-mentioned severe evaluation (Examples 164 to 166, 168 to 170).

<Creation of liquid crystal display element>
Below, a method for producing a liquid crystal cell for evaluating liquid crystal alignment and electro-optic response will be shown. First, a substrate with electrodes was prepared. The substrate used was an alkali-free glass substrate measuring 30 mm x 35 mm and having a thickness of 0.7 mm. An ITO (INDIUM-TIN-OXIDE) electrode is formed on the substrate with a comb-shaped pattern with an electrode width of 3 μm, an electrode spacing of 6 μm, and an angle of 10° with respect to the long side of the substrate. and formed pixels. The size of each pixel was 10 mm in length and about 5 mm in width. Hereinafter, it will be referred to as an IPS board.
Next, the liquid crystal aligning agents (WAS-1 to WAS-84) obtained by the above method and the liquid crystal aligning agent for horizontal alignment (NRB-U973 (manufactured by Nissan Chemical Co., Ltd.)) were each passed through a filter with a pore size of 1.0 mm. After filtering, the prepared IPS substrate and a glass substrate (hereinafter referred to as the counter substrate) having an ITO film formed on the back surface and having columnar spacers with a height of 3.0 μm were used as the counter substrate. Application and film formation were performed using a spin coating method. Next, it was dried on a hot plate at 80° C. for 2 minutes and then baked at 230° C. for 30 minutes to obtain a coating film with a thickness of 100 nm. The coating film on the IPS substrate was oriented in the direction along the comb-toothed direction, and the coating film on the counter substrate was oriented in the direction perpendicular to the comb-teeth electrodes. Note that a photo-alignment method was used for the alignment treatment of NRB-U973, and for WAS-1 to WAS-84, the substrates after firing were used as they were without any alignment treatment. In the photo-alignment method, a UV exposure device manufactured by Ushio Inc. was used to irradiate linearly polarized UV with an extinction ratio of about 26:1 so that the irradiation amount was 300 mJ/cm ² based on a wavelength of 254 nm. Thereafter, orientation treatment was performed by heating at 230° C. for 30 minutes.
After that, using the above two types of substrates, combine them in the combinations shown in Tables 10-1 to 10-3 below so that their orientation directions are parallel, and seal the periphery leaving the liquid crystal injection port ( Sealing agent: XN-1500T (manufactured by Mitsui Chemicals, Inc.)), heat treatment was performed at 150° C. for 60 minutes to harden the sealing agent, and empty cells with a cell gap of approximately 3.0 μm were prepared. After injecting liquid crystal (MLC-3019 (manufactured by Merck)) into this empty cell under vacuum at room temperature, the injection port was sealed to obtain an antiparallel-aligned liquid crystal cell.
The obtained liquid crystal cell constitutes an IPS type liquid crystal display element. Thereafter, the obtained liquid crystal cell was heat-treated at 120° C. for 10 minutes to obtain a liquid crystal display element.

<Evaluation of initial orientation>
Using a polarizing microscope, the polarizing plate was set to crossed nicols, the brightness of the liquid crystal cell was fixed at its lowest, and the liquid crystal cell was then rotated by 1° to observe the alignment state of the liquid crystal. Evaluation was performed by defining "good" when no or very slight orientation defects such as unevenness or domains were observed, and "poor" when clearly observed.

<Measurement of VT curve and evaluation of drive threshold voltage, maximum brightness voltage, and transmittance>
Set the white LED backlight and brightness meter so that the optical axes are aligned, set the liquid crystal cell (liquid crystal display element) with a polarizing plate attached so that the brightness is the lowest, and apply a voltage up to 8V at 1V intervals. The VT curve was measured by applying the voltage and measuring the brightness at the voltage. A voltage was applied from a state where no voltage was applied, and the voltage value (Vth) at 10% of the maximum transmitted brightness was estimated. The value of the voltage (Vmax) at which the brightness becomes maximum was estimated from the obtained VT curve. In addition, the maximum transmittance (Tmax) was estimated by setting the parallel Nicol transmission brightness as 100% through a liquid crystal cell with no voltage applied, and comparing the maximum transmission brightness on the VT curve.

<Measurement of response time (Ton, Toff)>
Using the device used to measure the VT curve above, connect the luminance meter to the oscilloscope, and measure the response speed (Ton) when applying the voltage that produces the maximum luminance and the response speed (Toff) when the voltage is returned to 0V. ) was measured.

<Evaluation of cell characteristics using photo-alignment>
(Evaluation results of weak anchoring IPS characteristics)
The details of the examples and the evaluation results are shown in Tables 10-1, 10-2, and 10-3.

In all of the IPS liquid crystal display devices produced using the weakly anchoring liquid crystal aligning agent of the present invention, a decrease in threshold voltage (Vth) and maximum brightness voltage (Vmax) was confirmed, and a decrease in maximum transmittance (Tmax) was confirmed. improvement was confirmed. On the other hand, a delay in response speed due to weak anchoring was also confirmed. From the above, it can be seen that even if a specific solvent is used as a solvent, good weak anchoring properties can be obtained without affecting the properties.

According to the present invention, it is possible to produce a stable weak anchoring film using an extremely simple method compared to conventional technology, so it is possible to reduce the process load and improve the yield in the production of weak anchoring IPS in actual industrialization. . In addition, by using the materials and methods of the present invention, while suppressing the occurrence of pre-tilt angles due to narrowing of the cell gap, we have achieved faster response when the voltage is turned off, reduced burn-in, and higher backlash in low-temperature environments compared to conventional technology. Since light transmittance and low voltage driving can be realized, it is possible to provide a material and a horizontal electric field liquid crystal display element that can stably exhibit excellent characteristics.

1 Horizontal electric field liquid crystal display element 2 Comb tooth electrode substrate

2a Base material

2b Linear electrode 2c Liquid crystal alignment film 2d Base material 2e Plane electrode 2f Insulating film 2g Linear electrode 2h Liquid crystal alignment film 3 Liquid crystal 4 Counter substrate 4a Liquid crystal alignment film 4b Base Material L Electric lines of force

Claims

Used for forming the liquid crystal alignment film of a liquid crystal cell having a liquid crystal and a liquid crystal alignment film,
A weakly anchoring liquid crystal aligning agent containing a polymer (P) obtained from a compound having a polymerizable group having a polymerizable unsaturated hydrocarbon group, and a compound represented by the following formula (1) as a solvent.

(In formula (S1), Q 1 and Q 2 each independently represent an alkyl group having 1 to 4 carbon atoms, and Q 3 represents a linear, branched, or cyclic alkyl group having 1 to 8 carbon atoms; represents an alkoxyalkyl group having 2 to 8 carbon atoms, an alkylcarbonylalkyl group having 4 to 8 carbon atoms, or a hydrogen atom, and the total number of carbon atoms of Q 1 , Q 2 and Q 3 is 4 or more.)
The compound represented by the formula (1) is N,N-diethylacetamide, N,N-diethylformamide, N,N-dibutylformamide, N,N-dipropylacetamide, N,N-dimethylpropionamide, N , N-diethylpropionamide, 3-methoxy-N,N-dimethylpropanamide, 2-methoxy-N,N-diethylacetamide, 3-methoxy-N,N-diethylpropanamide, 4-oxo-N,N- The weakly anchoring liquid crystal aligning agent according to claim 1, which is at least one selected from diethylpentanamide and N,N-diethylcyclohexanecarboxamide.
Weak anchoring according to claim 1, wherein the content of the compound represented by formula (1) is 10 to 90% by mass based on the total amount of solvent components contained in the weak anchoring liquid crystal aligning agent. Liquid crystal alignment agent.
The weakly anchoring liquid crystal aligning agent according to claim 1, wherein the polymer (P) is at least one selected from the group consisting of the following polymers (α) and polymers (β).
Polymer (α): A block copolymer having a block segment (A) that is compatible with the liquid crystal and a block segment (B) that is not compatible with the liquid crystal or becomes insolubilized in the liquid crystal upon firing.
Polymer (β): A graft copolymer having a trunk polymer and a branch polymer bonded to the trunk polymer as a side chain of the trunk polymer, and the branch polymer is compatible with the liquid crystal and the trunk polymer is not compatible with the liquid crystal or becomes insoluble in the liquid crystal upon firing.
The block segment (A) in the polymer (α) and the branch polymer in the polymer (β) are a compound represented by the following formula (2), a compound represented by the following formula (3), a compound represented by the following formula ( 4) and at least one selected from the group consisting of the compound represented by the following formula (5) as a constituent component,
The block segment (B) in the polymer (α) and the backbone polymer in the polymer (β) contain a compound represented by the following formula (6) as a constituent component,
The weak anchoring liquid crystal aligning agent according to claim 4.

(In formula (2), M represents a polymerizable group having a polymerizable unsaturated hydrocarbon group, and X represents a single bond, ether bond, ester bond, amide bond, urethane bond, urea bond, or thioether bond. , R 1 represents an alkyl group having 1 to 20 carbon atoms which may have a bonding group inserted therein, and n is an integer of 1 to 2. When n is 2, the two X and R 1 are each the same. (It may be different or it may be different.)

(In formula (3), M represents a polymerizable group having a polymerizable unsaturated hydrocarbon group, and S represents a single bond or a saturated hydrocarbon group having 1 to 6 carbon atoms which may have a bonding group inserted therein. , T represents an organic group represented by the following formula (3-T), and n is an integer of 1 to 2. When n is 2, the two Ts may be the same or different. (However, when n is 2, S represents a saturated hydrocarbon group having 1 to 6 carbon atoms that may have a bonding group inserted.)

(In formula (3-T), * indicates a bonding site. X is a single bond, ether bond, ester bond, amide bond, urethane bond, urea bond, thioether bond, -Si(R 1 )(R 2 )- (R 1 and R 2 each independently represent an alkyl group bonded to Si.), -Si(R 3 )(R 4 )-O-(R 3 and R 4 each independently bond to Si. represents an alkyl group), and -N(R 5 )-(R 5 represents a hydrogen atom or an alkyl group bonded to N), and Cy is a 6- to 20-membered non-ring group. (Represents an aromatic cyclic group.)

(In formula (4), M represents a polymerizable group having a polymerizable unsaturated hydrocarbon group, R 1 represents an aliphatic hydrocarbon group having a linear or branched structure having 1 to 10 carbon atoms, and 3 Each of the three X's independently represents a hydrogen atom or the following formula (4-X).However, at least one of the three X's represents the formula (4-X).)

(In formula (4-X), Y represents a single bond, -O-, -S-, or -N(R)-(R represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms bonded to N. ), and * indicates a bonding site. R 2 , R 3 , and R 4 each independently represent an alkyl group having 1 to 6 carbon atoms or an aromatic hydrocarbon group that may have a substituent. )

(In formula (5), M represents a polymerizable group having a polymerizable unsaturated hydrocarbon group, and R 1 to R 3 are each independently a single bond or the number of carbon atoms into which a bonding group may be inserted. represents an alkylene group of 1 to 6, Ar represents an aromatic hydrocarbon group that may have a substituent, and X 1 and X 2 are each independently a hydrogen atom, or R 1 X 1 and R 2 X 2 and the carbon atoms bonded to R 1 X 1 and R 2 X 2 may form a ring together. The total number of carbon atoms in R 1 X 1 , R 2 X 2 and R 3 is 1 or more.)

(In formula (6), M represents a polymerizable group having a polymerizable unsaturated hydrocarbon group, and n is an integer of 1 to 2. Z represents a group represented by the following formula (6-Z). (If n is 2, the two Zs may be the same or different.)

(In formula (6-Z), L is a trialkoxysilyl group, an isocyanate group, a blocked isocyanate group, an epoxy group, an oxetane group, a vinyl group, an allyl group, an oxazoline group, an amino group, a protected amino group, an aniline group, a protected aniline group) group, hydroxy group, protected hydroxy group, phenol group, protected phenol group, thiol group, protected thiol group, thiophenol group, protected thiophenol group, aldehyde group, carboxy group, maleimide group, N-hydroxysuccinimide ester group, bonding group Aromatic hydrocarbon group having 5 to 18 carbon atoms which may have a bonding group inserted therein, an aromatic heterocyclic group having 5 to 18 carbon atoms which may have a bonding group inserted therein, a cinnamic acid group, a cinnamic acid aromatic ester group , a cinnamic acid alkyl ester group, a cinnamyl group, a phenylbenzoate group, an azobenzene group, an N-benzylideneaniline group, a stilbene group, and a tolan group. J is a single bond or has 1 to 1 carbon atoms. 6 represents an aliphatic hydrocarbon group.When K is bonded to an aromatic hydrocarbon group, it represents a linking group selected from a single bond, ether bond, ester bond, amide bond, urea bond, urethane bond, and thioether bond. In other cases, it indicates a single bond. * represents a binding site. m is an integer from 1 to 3. When m is 2 or 3, multiple K and L may be the same. (However, if J is a single bond, m is 1.)
The weakly anchoring liquid crystal aligning agent according to claim 5, wherein the branch polymer in the polymer (β) is derived from a macromonomer represented by the following formula (7).

(In formula (7), P represents a polymerizable group having a polymerizable unsaturated hydrocarbon group, and Q represents a polymerizable monomer containing at least one of the compounds represented by formulas (2) to (5) above. (n is an integer of 1 to 2. When n is 2, the two Qs may be the same or different.)
M in the formula (2) is any of the structures represented below,
M in the formula (3) is any of the structures represented below,
M in the formula (4) is any of the structures represented below,
M in the formula (5) is any of the structures represented below,
M in the formula (6) is any of the structures represented below,
The weak anchoring liquid crystal aligning agent according to claim 5.

(In the formula, R 1 and R 2 each independently represent a hydrogen atom or a linear or branched alkyl group having 1 to 12 carbon atoms, and X, Y, and Z each independently represent an oxygen atom or a sulfur atom. *, * 1 and * 2 represent bonding sites, and either one of * 1 and * 2 may be replaced with a hydrogen atom or a straight chain or branched alkyl group having 1 to 12 carbon atoms.)
The polymer (α) and the polymer (β) contain as a constituent component at least one selected from the group consisting of compounds represented by the following formulas (B-1) to (B-17), The weak anchoring liquid crystal aligning agent according to claim 4.

(In formulas (B-1) to (B-17), Me represents a methyl group, and Et represents an ethyl group.)
A liquid crystal display element obtained using the weakly anchoring liquid crystal aligning agent according to any one of claims 1 to 8.
The liquid crystal display element according to claim 9, which is a horizontal electric field liquid crystal display element.
A method for manufacturing a liquid crystal display element, comprising applying and baking the weakly anchoring liquid crystal aligning agent according to any one of claims 1 to 8.
12. The method for manufacturing a liquid crystal display element according to claim 11, wherein the liquid crystal display element is a horizontal field liquid crystal display element.