WO2019181907A1 - Liquid crystal aligning agent, liquid crystal alignment film and liquid crystal display element - Google Patents

Abstract

The present invention provides: a highly efficient liquid crystal aligning agent which is provided with alignment control ability, while having excellent whitening resistance, and which enables the achievement of a liquid crystal alignment film that has excellent tilt angle characteristics and voltage holding ratio; a liquid crystal alignment film which is obtained from this liquid crystal aligning agent; and a liquid crystal display element. The present invention provides a liquid crystal aligning agent which contains: (A) an acrylic polymer that has a photo-alignment group and a carboxyl group; and (B) an amine compound which has one primary amino group and a hydroxyl group in each molecule, and wherein the primary amino group and the hydroxyl group are bonded to an aliphatic hydrocarbon group or a non-aromatic cyclic hydrocarbon group.

Description

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

The present invention relates to a liquid crystal aligning agent containing a specific polymer and a specific additive, a liquid crystal alignment film using the same, and a method for producing a substrate having the alignment film. Further, the present invention relates to a novel method for manufacturing a liquid crystal display element having excellent tilt angle characteristics.

The liquid crystal display element is known as a light, thin, and low power consumption display device and has been remarkably developed in recent years. The liquid crystal display element is configured, for example, by sandwiching a liquid crystal layer between a pair of transparent substrates provided with electrodes. In the liquid crystal display element, an organic film made of an organic material is used as the liquid crystal alignment film so that the liquid crystal is in a desired alignment state between the substrates.

That is, the liquid crystal alignment film is a component of the liquid crystal display element, and is formed on the surface of the substrate that holds the liquid crystal in contact with the liquid crystal, and plays a role of aligning the liquid crystal in a certain direction between the substrates. The liquid crystal alignment film may be required to play a role of controlling the pretilt angle of the liquid crystal in addition to the role of aligning the liquid crystal in a certain direction such as a direction parallel to the substrate. In such a liquid crystal alignment film, the ability to control the alignment of liquid crystal (hereinafter referred to as alignment control ability) is given by performing an alignment treatment on the organic film constituting the liquid crystal alignment film.

As a method for aligning a liquid crystal alignment film for imparting alignment control ability, a rubbing method has been conventionally known. The rubbing method is a method of rubbing (rubbing) the surface of an organic film such as polyvinyl alcohol, polyamide or polyimide on a substrate with a cloth such as cotton, nylon or polyester in the rubbing direction (rubbing direction). This is a method of aligning liquid crystals. Since this rubbing method can easily realize a relatively stable alignment state of liquid crystals, it has been used in the manufacturing process of conventional liquid crystal display elements. As an organic film used for the liquid crystal alignment film, a polyimide-based organic film excellent in reliability such as heat resistance and electrical characteristics has been mainly selected.

However, in the rubbing method of rubbing the surface of the liquid crystal alignment film made of polyimide or the like, generation of dust and static electricity may be a problem. In addition, due to the high definition of the liquid crystal surface element in recent years and the unevenness caused by the corresponding electrodes on the substrate and the switching active element for driving the liquid crystal, the surface of the liquid crystal alignment film cannot be uniformly rubbed with a cloth. In some cases, alignment of the liquid crystal could not be realized.

Therefore, a photo-alignment method has been actively studied as another method for aligning the liquid crystal alignment film without rubbing. There are various photo alignment methods. Anisotropy is formed in the organic film constituting the liquid crystal alignment film by linearly polarized light or collimated light, and the liquid crystal is aligned according to the anisotropy.

Among them, a photo-alignment type photo-alignment method is known. For example, polyvinyl cinnamate is used and irradiated with polarized ultraviolet rays to cause a dimerization reaction (crosslinking reaction) at the double bond portion of two side chains parallel to the polarized light. Furthermore, a pretilt angle appears by irradiating polarized ultraviolet rays in an oblique direction (see Non-Patent Document 1). In addition, when a side chain polymer having coumarin in the side chain is used, polarized UV light is irradiated to cause a photocrosslinking reaction in the coumarin part of the side chain parallel to the polarized light, and the liquid crystal is aligned in a direction parallel to the polarization direction. (See Non-Patent Document 2).

The liquid crystal alignment film also has a role of providing a certain tilt angle (pretilt angle) to the liquid crystal, and the provision of the pretilt angle has become an important issue in the development of liquid crystal alignment films (patents). Reference 1 to 3).

On the other hand, when a liquid crystal aligning agent containing a polymer is used, in the case of printing on a substrate, the polymer is precipitated by moisture absorption, the varnish causes a whitening phenomenon, and the resulting coating film is roughened. Become.

As a method for suppressing the whitening phenomenon of a varnish containing a polymer, the solvent having a high boiling point capable of suppressing the drying time of N-vinyl pyrrolidone, N-cyclohexyl pyrrolidone or the like to 50% or more of the solvent in order to solve the above problems Has been proposed (see Patent Document 4).

Japanese Patent Laid-Open No. 04-281427 Japanese Patent Laid-Open No. 05-043687 JP 10-333153 A Japanese Patent Laid-Open No. 5-117487

However, the conventional means proposed above are not always sufficient. For example, in the means using a high boiling point solvent in Patent Document 2, since these solvents are generally highly hygroscopic, the amount of use is small. It has been found that when it becomes large, the above-mentioned whitening phenomenon of the varnish of the liquid crystal aligning agent is increased, and the side effect of reducing the pretilt angle of the obtained liquid crystal aligning film is caused.

The present invention suppresses the whitening phenomenon and the phenomenon of generating foreign matter on the substrate in a liquid crystal aligning agent containing a photoreactive acrylic polymer having a carboxyl group, and further, the pretilt angle of the obtained liquid crystal aligning film It aims at providing the liquid crystal aligning agent which suppresses the fall of this and has a favorable voltage retention.
In addition to the above object, an object of the present invention is to provide a twisted nematic liquid crystal display element and an OCB liquid crystal display element having improved tilt angle characteristics, and a liquid crystal alignment film for the element.

As a result of intensive studies to achieve the above problems, the present inventors have found the following inventions.
<1> (A): an acrylic polymer having a photo-alignment group and a carboxyl group; and (B): one primary amino group and at least two hydroxyl groups in the molecule, and the primary amino group. A liquid crystal aligning agent comprising: an amine compound in which a group and a hydroxyl group are bonded to an aliphatic hydrocarbon group or a non-aromatic cyclic hydrocarbon group.
<2> (A): An acrylic polymer having a photo-alignment group and a carboxyl group is obtained from a monomer mixture containing the following monomer (A-1), monomer (A-2) and monomer (A-3) Liquid crystal aligning agent which is a copolymer.
Monomer (A-1): a monomer having one cinnamoyl moiety, 2 to 4 benzene rings not constituting the cinnamoyl moiety, and a polymerizable group;
Monomer (A-2): a monomer having one cinnamoyl moiety, one benzene ring that does not constitute the cinnamoyl moiety, and a polymerizable group;
Monomer (A-3): A monomer having a carboxyl group and a polymerizable group.
(The cinnamoyl moiety and the benzene ring may have a substituent.)

<3> The liquid crystal aligning agent according to claim 1, wherein the polymerizable group of the monomer (A-1) and the monomer (A-2) is an acryl group or a methacryl group.
<4> In the above item <1>, the monomer (A-1) and the monomer (A-2) are each independently a group represented by the following formula (1) and a group represented by the following formula (2). It is preferable that the monomer has a polymerizable group bonded to any one group selected from the group consisting of

In the formula, A, B and D each independently represent a single bond, —O—, —CH ₂ —, —COO—, —OCO—, —CONH— or —NH—CO—;
S is an alkylene group having 1 to 12 carbon atoms, and each hydrogen atom bonded thereto may be independently replaced with a halogen group;
T is a single bond or an alkylene group having 1 to 12 carbon atoms, and a hydrogen atom bonded thereto may be replaced with a halogen group;
When T is a single bond, B also represents a single bond;
Y ₁ is a divalent benzene ring;
P ₁ , Q ₁ and Q ₂ are each independently a group selected from the group consisting of a benzene ring and an alicyclic hydrocarbon ring having 5 to 8 carbon atoms;
R ₁ is a hydrogen atom, —CN, halogen group, alkyl group having 1 to 5 carbon atoms, (alkyl having 1 to 5 carbon atoms) carbonyl group, cycloalkyl group having 3 to 7 carbon atoms, or 1 to 5 carbon atoms. It is an alkyloxy group.

In Y ₁ , P ₁ , Q ₁ and Q ₂ , each hydrogen atom bonded to the benzene ring is independently —CN, a halogen group, an alkyl group having 1 to 5 carbon atoms, or an (alkyl group having 1 to 5 carbon atoms) carbonyl group. Or may be substituted with an alkyloxy group having 1 to 5 carbon atoms;
X ₁ and X ₂ each independently represents a single bond, —O—, —COO— or —OCO—;
n1 and n2 are each independently 0, 1 or 2,
When the number of X ₁ is 2, X ₁ may be the same or different, and when the number of X ₂ is 2, X ₂ may be the same or different;
When the number of Q ₁ is 2, Q ₁ may be the same or different, and when the number of Q ₂ is 2, Q ₂ may be the same or different;
In the monomer (A-1), the total number of benzene rings other than Y ₁ is 2 to 4;
In the monomer (A-2), the total number of benzene rings other than Y ₁ is 1;
A broken line represents a bond with a polymerizable group.

<5> A compound in which the amine compound of component (B) is represented by the following formula [1] (in the formula [1], X ₁ , X ₂ and X ₃ are each independently an alkyl group or a hydroxyalkyl group). The liquid crystal aligning agent as described in said (1) which is.

<6> The liquid crystal aligning agent according to the above <5>, wherein in formula [1], X ₁ , X ₂ and X ₃ are all hydroxyalkyl groups.
<7> A liquid crystal alignment film obtained using the liquid crystal aligning agent according to any one of <1> to <6>.
<8> A liquid crystal display device having the liquid crystal alignment film according to <7>.

According to the liquid crystal aligning agent of the present invention, whitening phenomenon or foreign matter is generated on the substrate, and the phenomenon that the foreign matter aggregates to cause gap unevenness is suppressed, and further, the pretilt angle of the obtained liquid crystal alignment film is reduced. A liquid crystal alignment film that is suppressed and has a good voltage holding ratio can be obtained, and by using such a liquid crystal alignment film, a highly reliable liquid crystal display element can be produced with a high yield even in the case of a large size and a high definition.
Mechanism of why the use of the liquid crystal aligning agent of the present invention can suppress the phenomenon of whitening and the generation of foreign matter on the substrate, and further suppress the decrease in the pretilt angle of the liquid crystal alignment film obtained. Is not necessarily clear, but is considered as follows.

The molecule (B) contained in the liquid crystal aligning agent of the present invention has one primary amino group and a hydroxyl group in the molecule, and the primary amino group and the hydroxyl group are aliphatic hydrocarbon groups or non-aromatics. In the amine compound bonded to the cyclic hydrocarbon group, the primary amino group of the compound forms a salt with the carboxylic acid group in the polymer, so that the solubility of the polymer in water is increased, and the component (B) It is considered that resistance to whitening is improved as a result of suppression of the reaction between the two. Further, due to the presence of the hydroxyl group, the components (B) are bonded to each other by the reaction between the primary amino group and the hydroxyl group at the time of firing the alignment film, whereby the component (B) is not eluted into the liquid crystal, and the voltage is increased. It is considered that characteristics such as retention rate and tilt angle do not deteriorate.
The twisted nematic liquid crystal display element and OCB type liquid crystal display element manufactured by the method of the present invention are imparted with an alignment control ability with high efficiency, so that display characteristics are not impaired even when driven continuously for a long time.

The liquid crystal aligning agent used in the production method of the present invention includes (A) an acrylic polymer having a photo-alignable group and a carboxyl group (hereinafter also simply referred to as a side chain polymer); and (B) 1 in the molecule. An amine compound having one primary amino group and at least two hydroxyl groups, and wherein the primary amino group and hydroxyl group are bonded to an aliphatic hydrocarbon group or a non-aromatic cyclic hydrocarbon group (hereinafter, specified The coating film obtained by using the liquid crystal aligning agent is a film having a photosensitive side chain polymer that can exhibit liquid crystallinity. This coating film is subjected to orientation treatment by irradiation with polarized light without being rubbed. And after polarized light irradiation, it will become the coating film (henceforth a liquid crystal aligning film) to which the orientation control ability was provided through the process of heating the side chain type polymer film. At this time, the slight anisotropy developed by the irradiation of polarized light becomes a driving force, and the liquid crystalline side chain polymer itself is efficiently reoriented by self-organization. As a result, a highly efficient alignment process can be realized as the liquid crystal alignment film, and a liquid crystal alignment film with high alignment control ability can be obtained.

In the liquid crystal aligning agent of the present invention, the primary amino group in the specific amine compound forms a salt with the carboxyl group in the specific polymer, or the carboxyl group or carboxy ester group in the specific polymer. Thus, it is considered that the amide bond is accompanied by elimination of water or alcohol. Furthermore, it is considered that the primary amino group that forms a salt with the carboxyl group in the specific polymer forms an amide bond due to elimination of water in the baking step in producing the liquid crystal alignment film. As a result, although the liquid crystal aligning agent of the present invention is a simple means of mixing in an organic solvent, the specific amine compound and the specific polymer are efficiently bonded in the liquid crystal alignment film obtained therefrom. I think.

Furthermore, in the present invention, since the specific amine compound that causes the crosslinking reaction is bonded to the specific polymer, the characteristics of the liquid crystal display element are deteriorated due to remaining unreacted components that occur when the crosslinking compound is added. There is no problem.

In this specific amine compound, since the primary amino group contained in the molecule forms a salt with the carboxyl group in the specific polymer, the polymer is used when preparing the liquid crystal aligning agent or during storage of the liquid crystal aligning agent. The possibility of problems such as precipitation and gelation can be avoided.

Hereinafter, embodiments of the present invention will be described in detail.
<Liquid crystal aligning agent>
This application
(A): an acrylic polymer having a photo-alignment group and a carboxyl group; and (B): one primary amino group and at least two hydroxyl groups in the molecule, and the primary amino group and the hydroxyl group. An amine compound in which is bound to an aliphatic hydrocarbon group or a non-aromatic cyclic hydrocarbon group;
The liquid crystal aligning agent containing is provided. Hereinafter, the component (A) (side chain polymer) and the component (B) (specific amine compound) will be described.

<< (A) Side chain polymer >>
The component (A) is an acrylic polymer having a photoalignment group and a carboxyl group.
More specifically, the component (A) is a copolymer obtained from a monomer mixture containing the following monomer (A-1), monomer (A-2) and monomer (A-3).
Monomer (A-1): a monomer having one cinnamoyl moiety, 2 to 4 benzene rings that do not constitute the cinnamoyl moiety, and a polymerizable group.
Monomer (A-2): a monomer having one cinnamoyl moiety, one benzene ring that does not constitute the cinnamoyl moiety, and a polymerizable group.
Monomer (A-3): A monomer having a carboxyl group and a polymerizable group.
The cinnamoyl moiety and the benzene ring may have a substituent.

(A) In the side chain type polymer, a side chain having photosensitivity is bonded to the main chain, and can react with light to cause a crosslinking reaction and an isomerization reaction. The structure of the side chain having photosensitivity is not particularly limited, but a structure that causes a crosslinking reaction in response to light is desirable. In this case, even if exposed to external stress such as heat, the achieved orientation control ability can be stably maintained for a long period of time.

More specific examples of the structure of the side chain polymer of component (A) include hydrocarbon, (meth) acrylate, itaconate, fumarate, maleate, α-methylene-γ-butyrolactone, styrene, vinyl, maleimide, and norbornene. A structure having a main chain composed of at least one selected from the group consisting of radically polymerizable groups such as siloxane and the like and a side chain consisting of at least one of the following formulas (1) and (2) preferable.

In the formula, A, B, D, S, T, Y ₁ , P ₁ , Q ₁ , Q ₂ , R ₁ , X ₁ , X ₂ , n 1, and n ₂ , and the broken line are the same as defined above. .
In the monomer (A-1), the total number of benzene rings other than Y ₁ is 2 to 4;
In the monomer (A-2), the total number of benzene rings other than Y ₁ is 1;

The content of the side chain derived from (A-1) in the total of the content of the side chain derived from (A-1) and the content of the side chain derived from (A-2) in the side chain type polymer of the present invention Is preferably from 10 mol% to 90 mol%, more preferably from 20 mol% to 80 mol%, still more preferably from 30 mol% to 70 mol%, from the viewpoints of liquid crystal alignment and solubility of the side chain polymer.

The side chain polymer of the present invention contains side chains derived from (A-1) and other side chains other than the side chain derived from (A-2) as long as the effects of the present invention are not impaired. Also good. The content is the remaining portion when the total content of the photoreactive side chain and the liquid crystalline side chain is less than 100%.

<< Production Method of Photosensitive Side Chain Polymer >>
The photosensitive side chain polymer capable of exhibiting the above liquid crystallinity can be obtained by polymerizing a monomer mixture containing at least the monomer (A-1) and the monomer (A-2).

[Monomer (A-1), Monomer (A-2) and Monomer (A-3)]
The photoreactive side chain monomer is a monomer capable of forming a polymer having a photosensitive side chain at the side chain portion of the polymer when the polymer is formed.
As the photoreactive group possessed by the side chain, the following structures and derivatives thereof are preferred.

More specific examples of the monomer (A-1) and the monomer (A-2) include hydrocarbon, (meth) acrylate, itaconate, fumarate, maleate, α-methylene-γ-butyrolactone, styrene, vinyl, maleimide, Photosensitivity selected from a polymerizable group composed of at least one selected from the group consisting of radically polymerizable groups such as norbornene and trialkoxysilyl groups, and structures represented by the above formulas (1) and (2) A structure having a side chain is preferred.

The polymerizable group is preferably selected from groups represented by the following formulas PG1 to PG8. Among these, an acrylic group or a methacryl group represented by PG1 is preferable from the viewpoint of easy control of the polymerization reaction and the stability of the polymer. In the formula, the broken line represents a bond with the photosensitive side chain represented by the formula (1) or (2). In formula PG1, M ¹ is a hydrogen atom or a methyl group.

Examples of the monomer (A-1) include monomers selected from the following formulas A-1-1 to A-1-7. In formulas A-1-1 to A-1-7, PG represents a polymerizable group selected from the groups represented by formulas PG1 to PG8, and s1 and s2 each independently represents the number of methylene groups. A natural number of 9 to 9.

Examples of the monomer (A-2) include monomers selected from the following formulas A-2-1 to A-2-14.

In formulas A-2-1 to A-2-14, PG represents a polymerizable group selected from the groups represented by formulas PG1 to PG8, and s1 and s2 each independently represents the number of methylene groups. A natural number of 9 to 9.

Examples of the monomer (A-3) include monomers selected from the following formulas A-3-1 to A-3-4. In formulas A-3-1 to A-3-4, PG represents a polymerizable group selected from the groups represented by formulas PG1 to PG8, and s1 and s2 each independently represents the number of methylene groups. A natural number of 9 to 9.

Some of the monomer (A-1), monomer (A-2) and monomer (A-3) are commercially available, and some are produced by the method described in, for example, International Patent Application Publication WO2014 / 074785. can do.

(A) The side chain polymer can be obtained by the copolymerization reaction of the monomer (A-1), monomer (A-2) and monomer (A-3) described above. Furthermore, it can be copolymerized with other monomers as long as the liquid crystallinity is not impaired.

When the polymerizable group of the monomer (A-1), the monomer (A-2), and the monomer (A-3) is a radical polymerizable group, the other monomer may be a radical polymerization reaction that is industrially available, for example. Monomer.
Specific examples of the other monomer include unsaturated carboxylic acid, acrylic ester compound, methacrylic ester compound, maleimide compound, acrylonitrile, maleic anhydride, styrene compound and vinyl compound.

Specific examples of the unsaturated carboxylic acid include acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid and the like.

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

Examples of the methacrylic acid ester compound include methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, benzyl methacrylate, naphthyl methacrylate, anthryl methacrylate, anthryl methyl methacrylate, phenyl methacrylate, 2,2,2-trifluoroethyl methacrylate, tert-butyl. Methacrylate, lauryl methacrylate, palmityl methacrylate, cyclohexyl methacrylate, isobornyl methacrylate, 2-methoxyethyl methacrylate, methoxytriethylene glycol methacrylate, 2-ethoxyethyl methacrylate, tetrahydrofurfuryl methacrylate, 3-methoxybutyl methacrylate, 2-methyl- 2-adamantyl methacrylate, 2 Propyl-2-adamantyl methacrylate, 8-methyl-8-tricyclodecyl methacrylate, and, 8-ethyl-8-tricyclodecyl methacrylate.

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

Examples of the styrene compound include styrene, methyl styrene, chlorostyrene, bromostyrene, and the like.

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

The content of the photoreactive side chain derived from the monomer (A-1) and the monomer (A-2) in the side chain polymer of the present invention is 10 mol% to 95 mol% from the viewpoint of liquid crystal alignment. It is preferably 20 mol% to 90 mol%, more preferably 30 mol% to 80 mol%.
Further, the content of the carboxyl group derived from the monomer (A-3) is preferably from 5 mol% to 90 mol%, more preferably from 10 mol% to 80 mol%, still more preferably from 20 mol% to 70 mol%.

The method for producing the side chain polymer of the present embodiment is not particularly limited, and a general-purpose method that is handled industrially can be used. Specifically, it can be produced by cationic polymerization, radical polymerization, or anionic polymerization using the vinyl groups of the monomer (A-1), monomer (A-2) and monomer (A-3). Among these, radical polymerization is particularly preferable from the viewpoint of ease of reaction control.
As conditions for the polymerization initiator, reaction temperature, solvent and the like of radical polymerization, known conditions described in International Patent Application Publication No. WO2014 / 074785 can be used.

[Recovery of polymer]
When recovering the produced polymer from the reaction solution of the photosensitive side chain polymer capable of exhibiting liquid crystallinity obtained by the above reaction, the reaction solution is put into a poor solvent, The coalescence can be precipitated. 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, and water. The polymer deposited in a poor solvent and precipitated can be recovered by filtration and then dried at normal temperature or under reduced pressure at room temperature or by heating. In addition, when the polymer collected by precipitation is redissolved in an organic solvent and reprecipitation and collection is repeated 2 to 10 times, impurities in the polymer can be reduced. Examples of the poor solvent at this time include alcohols, ketones, hydrocarbons and the like, and it is preferable to use three or more kinds of poor solvents selected from these because purification efficiency is further improved.

The molecular weight of the (A) side chain polymer of the present invention is measured by a GPC (Gel Permeation Chromatography) method in consideration of the strength of the obtained coating film, workability at the time of forming the coating film, and uniformity of the coating film. The weight average molecular weight is preferably 2,000 to 1,000,000, more preferably 5,000 to 100,000.

<(B) Specific amine compound>
The specific amine compound as the component (B) used in the present invention has one primary amino group and at least two hydroxyl groups in the molecule, and the primary amino group and the hydroxyl group are aliphatic hydrocarbon groups or An amine compound bonded to a non-aromatic cyclic hydrocarbon group. In other words, the specific amine compound (B) of the present invention has one primary amino group and at least two hydroxyl groups in the molecule, and the hydroxyl group is an aliphatic hydrocarbon group or a non-aromatic cyclic group. The amine compound is bonded to the primary amino group through a hydrocarbon group.
More specifically, it is a compound represented by the following formula [1]. In the formula [1], X ₁ and X ₂ are each independently a hydroxyalkyl group, and X ₃ is a hydrogen atom, an alkyl group or a hydroxyalkyl group.

In the above formula [1], a compound in which X ₁ , X ₂ and X ₃ are all hydroxyalkyl groups is particularly preferred. The hydroxyalkyl group is preferably an alkyl group having one hydroxy group. Moreover, since it is preferable that the distance between the hydroxy group and the amino group is short, a group selected from a hydroxyethyl group and a hydroxymethyl group is preferable, and a hydroxymethyl group is particularly preferable. As the alkyl group, a group selected from a methyl group and an ethyl group is particularly preferable.
As the compound represented by the formula [1], for example, a compound represented by the following formula is preferable.

<Organic solvent>
The organic solvent used for the liquid crystal aligning agent of this invention will not be specifically limited if it is an organic solvent in which a resin component is dissolved. Specific examples are given below.
N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, N-methylcaprolactam, 2-pyrrolidone, N-ethylpyrrolidone, N-vinylpyrrolidone, dimethylsulfoxide, tetramethylurea, pyridine, Dimethylsulfone, hexamethylsulfoxide, γ-butyrolactone, 3-methoxy-N, N-dimethylpropanamide, 3-ethoxy-N, N-dimethylpropanamide, 3-butoxy-N, N-dimethylpropanamide, 1,3 -Dimethyl-imidazolidinone, ethyl amyl ketone, methyl nonyl ketone, methyl ethyl ketone, methyl isoamyl ketone, methyl isopropyl ketone, cyclohexanone, ethylene carbonate, propylene carbonate, diglyme, 4-hydroxy-4 Methyl-2-pentanone, propylene glycol monoacetate, propylene glycol monomethyl ether, propylene glycol-tert-butyl ether, dipropylene glycol monomethyl ether, diethylene glycol, diethylene glycol monoacetate, diethylene glycol dimethyl 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, etc. Is mentioned. These may be used alone or in combination.

[Preparation of liquid crystal aligning agent]
It is preferable that the liquid crystal aligning agent of this invention is prepared as a coating liquid so that it may become suitable for formation of a liquid crystal aligning film. That is, the liquid crystal aligning agent of the present invention is preferably prepared as a solution in which a resin component for forming a resin film is dissolved in an organic solvent. Here, the resin component is a resin component containing the side chain polymer that is the component (A) already described. In that case, the content of the resin component is preferably 1% by mass to 20% by mass, more preferably 3% by mass to 15% by mass, and particularly preferably 3% by mass to 10% by mass.

In the liquid crystal aligning agent of the present invention, the above-mentioned resin component may be a side chain type polymer that is all the component (A), but other polymers may be used as long as the liquid crystal aligning ability is not impaired. It may be mixed. In that case, the content of the other polymer in the resin component is 0.5 to 80% by mass, preferably 1 to 50% by mass.
Such other polymers are composed of, for example, poly (meth) acrylate, polyamic acid, polyimide, and the like, and examples thereof include polymers other than the side chain type polymer as the component (A).

The polymer composition used in the present invention may contain components other than the side chain polymer as the component (A), the specific amine compound as the component (B), and the organic solvent. Examples thereof include solvents and compounds that improve film thickness uniformity and surface smoothness when a liquid crystal aligning agent is applied, compounds that improve the adhesion between the liquid crystal alignment film and the substrate, and the like. It is not limited to this.

The following are mentioned as a specific example of the solvent (poor solvent) which improves the uniformity of film thickness and surface smoothness.
For example, isopropyl alcohol, methoxymethylpentanol, methyl cellosolve, ethyl cellosolve, butyl cellosolve, methyl cellosolve acetate, ethyl cellosolve acetate, butyl carbitol, ethyl carbitol, ethyl carbitol acetate, ethylene glycol, ethylene glycol monoacetate, ethylene glycol monoacetate Isopropyl ether, ethylene glycol monobutyl ether, propylene glycol, propylene glycol monoacetate, propylene glycol monomethyl ether, propylene glycol-tert-butyl ether, dipropylene glycol monomethyl ether, diethylene glycol, diethylene glycol monoacetate, diethylene glycol dimethyl ether, dipro Lenglycol 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, 1-hexanol, n-hexane, n-pentane, n-octane Diethyl ether, methyl lactate, ethyl lactate, methyl acetate, ethyl acetate, n-butyl acetate, propylene glycol monoethyl ether, methyl pyruvate, ethyl pyruvate, 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 monoacetate, propylene glycol diacetate, propylene glycol-1-monomethyl ether-2-acetate, propylene glycol- 1-monoethyl ether-2-acetate, dipropylene glycol, 2- (2-ethoxypropoxy) propanol, lactate methyl ester, lactate ethyl ester, lactate n-propyl ester, lactate n-butyl ester, lactyl isoamyl ester, etc. Examples include solvents having surface tension.

These poor solvents may be used alone or in combination. When using the solvent as described above, it is preferably 5% by mass to 80% by mass of the total solvent, more preferably so as not to significantly reduce the solubility of the entire solvent contained in the polymer composition. Is 20% by mass to 60% by mass.

Examples of the compound that improves film thickness uniformity and surface smoothness include fluorine-based surfactants, silicone-based surfactants, and nonionic surfactants.
More specifically, for example, Ftop (registered trademark) 301, EF303, EF352 (manufactured by Tochem Products), MegaFac (registered trademark) F171, F173, R-30 (manufactured by DIC), Florard FC430, FC431 (Manufactured by Sumitomo 3M), Asahi Guard (registered trademark) AG710 (manufactured by Asahi Glass), Surflon (registered trademark) S-382, SC101, SC102, SC103, SC104, SC105, SC106 (manufactured by AGC Seimi Chemical) It is done. The use ratio of these surfactants is preferably 0.01 to 2 parts by mass, more preferably 0.01 to 1 part by mass with respect to 100 parts by mass of the resin component contained in the polymer composition. Part by mass.

Specific examples of the compound that improves the adhesion between the liquid crystal alignment film and the substrate include the following functional silane-containing compounds.
For example, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 2-aminopropyltrimethoxysilane, 2-aminopropyltriethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-ureidopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, N-ethoxycarbonyl-3-aminopropyltrimethoxysilane, N-ethoxy Carbonyl-3-aminopropyltriethoxysilane, N-triethoxysilylpropyltriethylenetriamine, N-trimethoxysilylpropyltriethylenetriamine, 10-trimethoxysilyl-1,4,7-triazadecane, 10-to Ethoxysilyl-1,4,7-triazadecane, 9-trimethoxysilyl-3,6-diazanonyl acetate, 9-triethoxysilyl-3,6-diazanonyl acetate, N-benzyl-3-aminopropyltri Methoxysilane, N-benzyl-3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltriethoxysilane, N-bis (oxyethylene) -3-amino Examples thereof include propyltrimethoxysilane and N-bis (oxyethylene) -3-aminopropyltriethoxysilane.

Furthermore, in addition to improving the adhesion between the substrate and the liquid crystal alignment film, the addition of the following phenoplasts and epoxy group-containing compounds for the purpose of preventing the deterioration of electrical characteristics due to the backlight when the liquid crystal display element is constructed An agent may be contained in the liquid crystal aligning agent. Specific phenoplast additives are shown below, but are not limited to this structure.

Specific epoxy group-containing compounds include ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, 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-xylenediamine, 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane, N, N, N ′, N ′,-tetraglycidyl- , 4'-diaminodiphenylmethane and the like.

When using a compound that improves the adhesion to the substrate, the amount used is preferably 0.1 to 30 parts by mass with respect to 100 parts by mass of the resin component contained in the liquid crystal aligning agent. More preferably, it is 1 to 20 parts by mass. If the amount used is less than 0.1 parts by mass, the effect of improving the adhesion cannot be expected, and if it exceeds 30 parts by mass, the orientation of the liquid crystal may deteriorate.

A photosensitizer can also be used as an additive. Colorless and triplet sensitizers are preferred.
As photosensitizers, aromatic nitro compounds, coumarins (7-diethylamino-4-methylcoumarin, 7-hydroxy4-methylcoumarin), ketocoumarins, carbonyl biscoumarins, aromatic 2-hydroxyketones, and amino-substituted Aromatic 2-hydroxyketones (2-hydroxybenzophenone, mono- or di-p- (dimethylamino) -2-hydroxybenzophenone), acetophenone, anthraquinone, xanthone, thioxanthone, benzanthrone, thiazoline (2-benzoylmethylene-3 -Methyl-β-naphthothiazoline, 2- (β-naphthoylmethylene) -3-methylbenzothiazoline, 2- (α-naphthoylmethylene) -3-methylbenzothiazoline, 2- (4-biphenoylmethylene)- 3-methylbenzothia Phosphorus, 2- (β-naphthoylmethylene) -3-methyl-β-naphthothiazoline, 2- (4-biphenoylmethylene) -3-methyl-β-naphthothiazoline, 2- (p-fluorobenzoylmethylene)- 3-methyl-β-naphthothiazoline), oxazoline (2-benzoylmethylene-3-methyl-β-naphthoxazoline, 2- (β-naphthoylmethylene) -3-methylbenzoxazoline, 2- (α-naphthoylmethylene) ) -3-methylbenzoxazoline, 2- (4-biphenoylmethylene) -3-methylbenzoxazoline, 2- (β-naphthoylmethylene) -3-methyl-β-naphthoxazoline, 2- (4-biphenoyl) Methylene) -3-methyl-β-naphthoxazoline, 2- (p-fluorobenzoylmethylene) -3-methyl-β- Ftoxazoline), benzothiazole, nitroaniline (m- or p-nitroaniline, 2,4,6-trinitroaniline) or nitroacenaphthene (5-nitroacenaphthene), (2-[(m-hydroxy-p -Methoxy) styryl] benzothiazole, benzoin alkyl ether, N-alkylated phthalone, acetophenone ketal (2,2-dimethoxyphenylethanone), naphthalene, anthracene (2-naphthalenemethanol, 2-naphthalenecarboxylic acid, 9-anthracenemethanol And 9-anthracenecarboxylic acid), benzopyran, azoindolizine, melocoumarin and the like.
Aromatic 2-hydroxy ketone (benzophenone), coumarin, ketocoumarin, carbonyl biscoumarin, acetophenone, anthraquinone, xanthone, thioxanthone, and acetophenone ketal are preferred.

<Manufacturing method of substrate having liquid crystal alignment film> and <Manufacturing method of liquid crystal display element>
The method for producing a substrate having the liquid crystal alignment film of the present invention is as follows.
[I] A step of applying a liquid crystal aligning agent containing (A) a side chain polymer, a specific amine compound (B) component and an organic solvent on a substrate having a transparent electrode;
[II] a step of irradiating the coating film obtained in [I] with polarized ultraviolet rays; and [III] a step of heating the coating film obtained in [II];
Have
Through the above steps, a liquid crystal alignment film for a liquid crystal display element to which alignment control ability is imparted can be obtained, and a substrate having the liquid crystal alignment film can be obtained.

Moreover, a liquid crystal display element can be obtained by preparing a 2nd board | substrate other than the obtained board | substrate (1st board | substrate).
The second substrate can be obtained by using the above steps [I] to [III] on the second substrate having a transparent electrode to obtain a second substrate having a liquid crystal alignment film imparted with alignment control ability. it can.

The manufacturing method of the twist nematic type liquid crystal display element and the OCB type liquid crystal display element is as follows:
[IV] A step of obtaining a liquid crystal display element by arranging the first and second substrates obtained above so that the liquid crystal alignment films of the first and second substrates face each other with liquid crystal interposed therebetween;
Have Thereby, a twisted nematic liquid crystal display element can be obtained.
The steps [I] to [III] and [IV] of the production method of the present invention will be described below.

<Process [I]>
In step [I], a liquid crystal aligning agent containing (A) a side chain polymer, (B) a specific amine compound and an organic solvent is applied onto a substrate having an electrode for driving liquid crystal, and a coating film is formed. Form.

<Board>
Although it does not specifically limit about a board | substrate, When the liquid crystal display element manufactured is a transmission type, it is preferable that a highly transparent board | substrate is used. In that case, there is no particular limitation, and a glass substrate or a plastic substrate such as an acrylic substrate or a polycarbonate substrate can be used.
As an electrode for driving the liquid crystal, ITO (Indium Tin Oxide), IZO (Indium Zinc Oxide), or the like is preferable. Further, in the reflection type liquid crystal display element, an opaque material such as a silicon wafer can be used as long as the substrate is only on one side, and in this case, a material that reflects light such as aluminum can be used.
A conventionally known method can be used as a method of forming an electrode on the substrate.

The method for applying the liquid crystal aligning agent described above on a substrate having an electrode for driving liquid crystal is not particularly limited.
In general, the application method is generally performed by screen printing, offset printing, flexographic printing, an inkjet method, or the like. Other coating methods include a dipping method, a roll coater method, a slit coater method, a spinner method (rotary coating method), or a spray method, and these may be used depending on the purpose.

After applying the liquid crystal aligning agent on the substrate having the electrodes for driving the liquid crystal, the temperature is set to 50 to 230 ° C., preferably 50 to 200 ° C. by a heating means such as a hot plate, a thermal circulation oven or an IR (infrared) oven. The coating film can be obtained by evaporating the solvent for 0.4 minutes to 60 minutes, preferably 0.5 minutes to 10 minutes. The drying temperature at this time is preferably lower than the temperature range of the temperature at which the side chain polymer of the side chain polymer as component (A) exhibits liquid crystallinity (hereinafter referred to as liquid crystal expression temperature).
If the thickness of the coating film is too thick, it will be disadvantageous in terms of power consumption of the liquid crystal display element, and if it is too thin, the reliability of the liquid crystal display element may be lowered. Therefore, it is preferably 5 nm to 300 nm, more preferably 10 nm to 150 nm. It is.
In addition, it is also possible to provide the process of cooling the board | substrate with which the coating film was formed to room temperature after the [I] process and before the following [II] process.

<Process [II]>
In step [II], the coating film obtained in step [I] is irradiated with ultraviolet rays polarized from an oblique direction. When irradiating the surface of the coating film with polarized ultraviolet rays, the substrate is irradiated with polarized ultraviolet rays through a polarizing plate from a certain direction. As the ultraviolet rays to be used, ultraviolet rays having a wavelength of 100 nm to 400 nm can be used. Preferably, the optimum wavelength is selected through a filter or the like depending on the type of coating film used. For example, ultraviolet light having a wavelength in the range of 290 nm to 400 nm can be selected and used so that the photocrosslinking reaction can be selectively induced. As the ultraviolet light, for example, light emitted from a high-pressure mercury lamp can be used.

The irradiation amount of polarized ultraviolet rays depends on the coating film used. The amount of irradiation is polarized ultraviolet light that realizes the maximum value of ΔA (hereinafter also referred to as ΔAmax), which is the difference between the ultraviolet light absorbance in a direction parallel to the polarization direction of polarized ultraviolet light and the ultraviolet light absorbance in a direction perpendicular to the polarization direction of the polarized ultraviolet light. The amount is preferably in the range of 1% to 70%, more preferably in the range of 1% to 50%.

The direction of irradiation of polarized ultraviolet rays is usually 1 ° to 89 ° with respect to the substrate, preferably 10 ° to 80 °, particularly preferably 20 ° to 70 °. When this angle is too small, there is a problem that the pretilt angle becomes small, and when it is too large, there is a problem that the pretilt angle becomes high.

As a method of adjusting the irradiation direction to the above angle, there are a method of tilting the substrate itself and a method of tilting the light source. It is more preferable to tilt the light source itself from the viewpoint of throughput.
The pretilt angle obtained is preferably 1 ° to 20 °, more preferably 2 ° to 15 °, as a pretilt angle suitable for the twisted nematic mode.

<Step [III]>
In step [III], the ultraviolet-irradiated coating film polarized in step [II] is heated. An orientation control ability can be imparted to the coating film by heating.
For heating, a heating means such as a hot plate, a heat circulation type oven, or an IR (infrared) type oven can be used. The heating temperature can be determined in consideration of the temperature at which the liquid crystallinity of the coating film used is developed.

The heating temperature is preferably within the temperature range of the temperature at which the side chain polymer exhibits liquid crystallinity (hereinafter referred to as liquid crystal expression temperature). In the case of a thin film surface such as a coating film, the liquid crystal expression temperature on the coating film surface is expected to be lower than the liquid crystal expression temperature when the side chain polymer as the component (A) is observed in bulk. Therefore, the heating temperature is more preferably within the temperature range of the liquid crystal expression temperature on the coating film surface. That is, the temperature range of the heating temperature after irradiation with polarized ultraviolet rays is 10 ° C. lower than the lower limit of the temperature range of the liquid crystal expression temperature of the side chain polymer used, and 10 ° C. lower than the upper limit of the liquid crystal temperature range. It is preferable that it is the temperature of the range which makes an upper limit. If the heating temperature is lower than the above temperature range, the anisotropic amplification effect due to heat in the coating film tends to be insufficient, and if the heating temperature is too higher than the above temperature range, the state of the coating film Tends to be close to an isotropic liquid state (isotropic phase), and in this case, self-organization may make it difficult to reorient in one direction.
The liquid crystal expression temperature is not less than the glass transition temperature (Tg) at which the side chain polymer or coating film surface undergoes a phase transition from the solid phase to the liquid crystal phase, and from the liquid crystal phase to the isotropic phase (isotropic phase). It means a temperature below the isotropic phase transition temperature (Tiso) that causes a phase transition.

The thickness of the coating film formed after heating is preferably 5 nm to 300 nm, more preferably 50 nm to 150 nm for the same reason described in the step [I].
By having the above steps, the production method of the present invention can realize highly efficient introduction of anisotropy into the coating film. And a board | substrate with a liquid crystal aligning film can be manufactured highly efficiently.

<Process [IV]>
[IV] The process includes two substrates obtained in [III] arranged so that the side on which the liquid crystal alignment film is formed faces each other, a liquid crystal layer provided between the substrates, a substrate and a liquid crystal layer And a liquid crystal cell having the liquid crystal alignment film formed with the liquid crystal aligning agent of the present invention. As such a liquid crystal display element of the present invention, a twisted nematic (TN) method, a vertical alignment (VA) method, a horizontal alignment (IPS) method, an OCB alignment (OCB: OCB). There are various types such as Optically Compensated Bend).

To give an example of the production of a liquid crystal cell or a liquid crystal display element, the first and second substrates described above are prepared, spacers are dispersed on the liquid crystal alignment film of one substrate, and the liquid crystal alignment film surface is on the inside. In this way, the other substrate is bonded so that the ultraviolet light exposure directions are orthogonal to each other, and the liquid crystal is injected under reduced pressure to seal it, or after the liquid crystal is dropped on the liquid crystal alignment film surface on which the spacers are dispersed, The method of sticking together and performing sealing etc. can be illustrated. The diameter of the spacer at this time is preferably 1 μm to 30 μm, more preferably 2 μm to 10 μm. This spacer diameter determines the distance between the pair of substrates that sandwich the liquid crystal layer, that is, the thickness of the liquid crystal layer.

The obtained liquid crystal display element is preferably annealed for further alignment stability. The heating temperature is the phase transition temperature of the liquid crystal, preferably 10 to 160 ° C., more preferably 50 to 140 ° C.

The manufacturing method of the board | substrate with a coating film of this invention irradiates the polarized ultraviolet-ray, after apply | coating a liquid crystal aligning agent on a board | substrate and forming a coating film. Next, by heating, high-efficiency anisotropy is introduced into the side chain polymer film, and a substrate with a liquid crystal alignment film having a liquid crystal alignment control ability is manufactured.
The coating film used in the present invention realizes the introduction of highly efficient anisotropy into the coating film by utilizing the principle of molecular reorientation induced by the side chain photoreaction and liquid crystallinity. . In the production method of the present invention, in the case of a structure having a photocrosslinkable group as a photoreactive group in the side chain polymer, after forming a coating film on the substrate using the side chain polymer, polarized ultraviolet rays are formed. After irradiation and then heating, a liquid crystal display element is formed.

Therefore, the coating film used in the method of the present invention is a liquid crystal alignment film having anisotropy introduced with high efficiency and excellent alignment control ability by sequentially performing irradiation of polarized ultraviolet rays on the coating film and heat treatment. can do.

And in the coating film used for the method of the present invention, the irradiation amount of polarized ultraviolet rays to the coating film and the heating temperature in the heat treatment are optimized. Thereby, introduction of anisotropy into the coating film with high efficiency can be realized.

The optimum irradiation amount of polarized ultraviolet rays for introducing highly efficient anisotropy into the coating film used in the present invention is polarized light that optimizes the amount of photocrosslinking reaction or photoisomerization reaction of the photosensitive group in the coating film. Corresponds to the amount of UV irradiation. As a result of irradiating the coating film used in the present invention with polarized ultraviolet rays, if the photo-crosslinking reaction or the photoisomerization reaction of the side chain is small, the photoreaction amount is not sufficient. In that case, sufficient self-organization does not proceed even after heating. On the other hand, as a result of irradiating polarized ultraviolet rays to the structure having a photocrosslinkable group in the coating film used in the present invention, the crosslinking reaction between the side chains is caused when the photosensitive group of the side chain undergoing the crosslinking reaction becomes excessive. Too much progress. In that case, the resulting film may become rigid and hinder the progress of self-assembly by subsequent heating.

Therefore, in the coating film used in the present invention, the optimum amount of the photopolymerization reaction or photoisomerization reaction of the side chain photosensitive group by irradiation with polarized ultraviolet rays is the amount of the photosensitive group possessed by the side chain polymer film. The amount is preferably 0.1 mol% to 60 mol%, more preferably 0.1 mol% to 40 mol%. By making the amount of the photo-reactive side chain photosensitive group within such a range, the self-organization in the subsequent heat treatment proceeds efficiently, and the formation of highly efficient anisotropy in the film is possible. Become.

In the coating film used in the method of the present invention, by optimizing the irradiation amount of polarized ultraviolet rays, photocrosslinking reaction or photoisomerization reaction of photosensitive groups or photofleece rearrangement reaction in the side chain of the side chain polymer film Optimize the amount of. Then, in combination with the subsequent heat treatment, highly efficient introduction of anisotropy into the coating film used in the present invention is realized. In that case, a suitable amount of polarized ultraviolet rays can be determined based on the evaluation of ultraviolet absorption of the coating film used in the present invention.

That is, with respect to the coating film used in the present invention, the ultraviolet absorption in the direction parallel to the polarization direction of the polarized ultraviolet ray and the ultraviolet absorption in the vertical direction after the irradiation with the polarized ultraviolet ray are measured. From the measurement result of ultraviolet absorption, ΔA, which is the difference between the ultraviolet absorbance in the direction parallel to the polarization direction of polarized ultraviolet rays and the ultraviolet absorbance in the direction perpendicular to the polarization direction of the polarized ultraviolet rays, is evaluated. Then, the maximum value of ΔA (ΔAmax) realized in the coating film used in the present invention and the irradiation amount of polarized ultraviolet light that realizes it are obtained. In the production method of the present invention, a preferable amount of polarized ultraviolet rays to be irradiated in the production of the liquid crystal alignment film can be determined on the basis of the amount of polarized ultraviolet rays to realize this ΔAmax.

In the production method of the present invention, the amount of irradiation of polarized ultraviolet rays onto the coating film used in the present invention is preferably in the range of 1% to 70% of the amount of polarized ultraviolet rays that realizes ΔAmax. More preferably, it is within the range of 50%. In the coating film used in the present invention, the irradiation amount of polarized ultraviolet light within the range of 1% to 50% of the amount of polarized ultraviolet light that realizes ΔAmax is 0. 0% of the entire photosensitive group of the side chain polymer film. 1 mol% to 20 mol% corresponds to the amount of polarized ultraviolet light that undergoes a photocrosslinking reaction.

From the above, in the production method of the present invention, in order to achieve highly efficient anisotropy introduction into the coating film, a suitable heating temperature as described above is set based on the liquid crystal temperature range of the side chain polymer. It is good to decide. Therefore, for example, when the liquid crystal temperature range of the side chain polymer used in the present invention is 100 ° C. to 200 ° C., the heating temperature after irradiation with polarized ultraviolet light is desirably 90 ° C. to 190 ° C. By doing so, greater anisotropy is imparted to the coating film used in the present invention.

By doing so, the liquid crystal display element provided by the present invention exhibits high reliability against external stresses such as light and heat.

As described above, the twisted nematic type liquid crystal display element substrate manufactured by the method of the present invention or the liquid crystal display element having the substrate has excellent reliability, and can be used for a large-screen high-definition liquid crystal television. It can be suitably used.

EXAMPLES Hereinafter, although this invention is demonstrated using an Example, this invention is not limited to this Example. The abbreviations used in the examples are as follows.
<Methacrylic monomer>

MA-1 was synthesized by a synthesis method described in a patent document (Macromolecules 2007, 40, 6355-6360).
MA-2 was synthesized by the synthesis method described in the patent literature (British Patent GB 2306470B).
MA-3 was synthesized by a synthesis method described in a patent document (Japanese Patent Laid-Open No. 9-118717).
MA-4 was synthesized by a synthesis method described in a patent document (WO2014 / 054785).
T-1 was purchased from Tokyo Chemical Industry Co., Ltd. and used.
T-2 was purchased from Tokyo Chemical Industry Co., Ltd. and used.
T-3 was purchased from Tokyo Chemical Industry Co., Ltd. and used.
T-4 was purchased from Tokyo Chemical Industry Co., Ltd. and used.

<Organic solvent>
NMP: N-methyl-2-pyrrolidone BCS: Butyl cellosolve <polymerization initiator>
AIBN: 2,2′-azobisisobutyronitrile

<Synthesis Example 1: Methacrylic polymer>
MA-1 (34 g: 60 mmol), MA-2 (9 g: 20 mmol), MA-3 (6 g: 20 mmol) were dissolved in NMP (282 g), deaerated with a diaphragm pump, and then AIBN (0. 5 g: 3 mmol) was added and deaeration was performed again. Thereafter, the mixture was reacted at 60 ° C. for 6 hours to obtain a polymer solution of methacrylate. This polymer solution was added dropwise to methanol (2000 ml), and the resulting precipitate was filtered. This precipitate was washed with methanol and dried under reduced pressure to obtain methacrylate polymer powder P1.

<Synthesis Example 2: Methacrylic polymer>
MA-1 (34 g: 60 mmol), MA-2 (9 g: 20 mmol), MA-4 (9 g: 20 mmol) were dissolved in NMP (296 g), deaerated with a diaphragm pump, and then AIBN (0. 5 g: 3 mmol) was added and deaeration was performed again. Thereafter, the mixture was reacted at 60 ° C. for 6 hours to obtain a polymer solution of methacrylate. This polymer solution was added dropwise to methanol (2000 ml), and the resulting precipitate was filtered. This precipitate was washed with methanol and dried under reduced pressure to obtain methacrylate polymer powder P2.

<Preparation of liquid crystal aligning agent: A1>
NMP (8.4 g) was added to the methacrylate polymer powder P1 (0.6 g) obtained in Synthesis Example 1, and dissolved by stirring at room temperature for 1 hour. BCS (6.0 g) was added to this solution to obtain a polymer solution having a solid content concentration of 4.0 wt%. T-1 (0.03 g) was added to this polymer solution and dissolved by stirring at room temperature for 3 hours to obtain a polymer solution (A1). This polymer solution becomes a liquid crystal aligning agent for forming a liquid crystal alignment film as it is.
With respect to the liquid crystal aligning agents A2, B1, B2, and B3 under the conditions shown in Table 1, a liquid crystal aligning agent was prepared using the same method as the liquid crystal aligning agent A1.

<Preparation of liquid crystal aligning agent: B4>
NMP (8.4 g) was added to the methacrylate polymer powder P1 (0.6 g) obtained in Synthesis Example 1, and dissolved by stirring at room temperature for 1 hour. BCS (6.0 g) was added to this solution to obtain a polymer solution (B4) having a solid content concentration of 4.0 wt%. This polymer solution becomes a liquid crystal aligning agent for forming a liquid crystal alignment film as it is.
With respect to the liquid crystal aligning agent B5 under the conditions shown in Table 1, a liquid crystal aligning agent was produced using the same method as the liquid crystal aligning agent B4.

<Evaluation of whitening characteristics>
About 0.1 ml of the above liquid crystal aligning agent was dropped on each Cr substrate and left in an environment of a temperature of 23 ° C. and a humidity of 70%. The vicinity of the edge and the center of the droplet was observed with a microscope over time. The observation was performed at a magnification of 100 times near the edge of the droplet and at a magnification of 50 times near the center of the droplet. When aggregates were observed near the edge and center of the droplets within 30 minutes, the case where no aggregation was observed even after 1 hour was evaluated as ◯. The results are shown in Table 2.

<Production of liquid crystal cell>
The liquid crystal aligning agent (A1) was filtered through a 0.45 μm filter, spin-coated on a glass substrate with a transparent electrode, and dried on a hot plate at 40 ° C. for 5 minutes to form a liquid crystal aligning film having a thickness of 100 nm. .

(Example 1)
The coating surface was tilted by 60 °, and ultraviolet rays of 313 nm were irradiated through the polarizing plate to 40 mJ / cm ² of the substrate, followed by heating on a hot plate at 120 ° C. for 10 minutes to obtain a substrate with a liquid crystal alignment film. Two substrates with such a liquid crystal alignment film are prepared, a spacer of 4 μm is set on the liquid crystal alignment film surface of one of the substrates, and then combined so that the rubbing directions of the two substrates are parallel to each other. The periphery was sealed, and an empty cell with a cell gap of 4 μm was produced. Liquid crystal MLC-3019 (manufactured by Merck & Co., Inc.) was injected into the empty cell by a reduced pressure injection method, and the injection port was sealed to obtain an antiparallel liquid crystal cell. After heating for 30 minutes at a temperature of 120 ° C., the pretilt angle and voltage holding ratio (VHR) of this liquid crystal cell were measured.

For Example 2 and Comparative Examples 1 to 5 under the conditions shown in Table 2, a liquid crystal cell was prepared using the same method as in Example 1, and the pretilt angle and voltage holding ratio (VHR) were measured.

<Evaluation of voltage holding ratio (VHR)>
A voltage of 1V is applied to the liquid crystal cell produced above at a temperature of 70 ° C. for 60 μs, the voltage after 16.67 ms and 1000 ms is measured, and how much the voltage can be held is calculated as a voltage holding ratio (VHR). did. The voltage holding ratio was measured using a voltage holding ratio measuring device VHR-1 manufactured by Toyo Technica.

As shown in Table 2, the liquid crystal aligning agents of Examples 1 and 2 using additives are both liquid crystal pretilt suitable for twisted nematic mode or OCB mode compared to Comparative Examples 4 and 5 where no additives are used. It can be seen that corners and good whitening resistance can be obtained, and the voltage holding ratio (VHR) does not decrease. The reason why the voltage holding ratio (VHR) decreases in Comparative Examples 1 to 3 is presumed to be because the additive is eluted in the liquid crystal.

Claims (8)

1. (A): an acrylic polymer having a photo-alignment group and a carboxyl group; and (B): one primary amino group and at least two hydroxyl groups in the molecule, and the primary amino group and the hydroxyl group. A liquid crystal aligning agent comprising: an amine compound in which is bonded to an aliphatic hydrocarbon group or a non-aromatic cyclic hydrocarbon group.
2. (A) An acrylic polymer having a photo-alignment group and a carboxyl group is a copolymer obtained from a monomer mixture containing the following monomer (A-1), monomer (A-2) and monomer (A-3). A liquid crystal aligning agent according to claim 1.
   Monomer (A-1): a monomer having one cinnamoyl moiety, 2 to 4 benzene rings not constituting the cinnamoyl moiety, and a polymerizable group;
   Monomer (A-2): a monomer having one cinnamoyl moiety, one benzene ring that does not constitute the cinnamoyl moiety, and a polymerizable group;
   Monomer (A-3): A monomer having a carboxyl group and a polymerizable group.
   (The cinnamoyl moiety and the benzene ring may have a substituent.)
3. The liquid crystal aligning agent according to claim 1, wherein the polymerizable group of the monomer (A-1), the monomer (A-2) and the monomer (A-3) is an acryl group or a methacryl group.
4. The monomer (A-1) and the monomer (A-2) are each independently a group represented by the following formula (1) and a group represented by the following formula (2) (wherein A, B, D Each independently represents a single bond, —O—, —CH ₂ —, —COO—, —OCO—, —CONH— or —NH—CO—;
   S is an alkylene group having 1 to 12 carbon atoms, and each hydrogen atom bonded thereto may be independently replaced with a halogen group;
   T is a single bond or an alkylene group having 1 to 12 carbon atoms, and a hydrogen atom bonded thereto may be replaced with a halogen group;
   When T is a single bond, B also represents a single bond;
   Y ₁ is a divalent benzene ring;
   P ₁ , Q ₁ and Q ₂ are each independently a group selected from the group consisting of a benzene ring and an alicyclic hydrocarbon ring having 5 to 8 carbon atoms;
   R ₁ is a hydrogen atom, —CN, halogen group, alkyl group having 1 to 5 carbon atoms, (alkyl having 1 to 5 carbon atoms) carbonyl group, cycloalkyl group having 3 to 7 carbon atoms, or 1 to 5 carbon atoms. It is an alkyloxy group.
   In Y ₁ , P ₁ , Q ₁ and Q ₂ , each hydrogen atom bonded to the benzene ring is independently —CN, a halogen group, an alkyl group having 1 to 5 carbon atoms, or an (alkyl group having 1 to 5 carbon atoms) carbonyl group. Or may be substituted with an alkyloxy group having 1 to 5 carbon atoms;
   X ₁ and X ₂ each independently represents a single bond, —O—, —COO— or —OCO—;
   n1 and n2 are each independently 0, 1 or 2,
   When the number of X ₁ is 2, X ₁ may be the same or different, and when the number of X ₂ is 2, X ₂ may be the same or different;
   When the number of Q ₁ is 2, Q ₁ may be the same or different, and when the number of Q ₂ is 2, Q ₂ may be the same or different;
   In the monomer (A-1), the total number of benzene rings other than Y ₁ is 2 to 4;
   In the monomer (A-2), the total number of benzene rings other than Y ₁ is 1;
   A broken line represents a bond with a polymerizable group. )
   The liquid crystal aligning agent according to claim 1, which is a monomer in which a polymerizable group is bonded to any one group selected from the group consisting of:
   

   
5. In the amine compound of component (B), the following formula [1] (in formula [1], X ₁ and X ₂ are each independently a hydroxyalkyl group, and X ₃ is a hydrogen atom, an alkyl group or a hydroxyalkyl group. The liquid crystal aligning agent according to any one of claims 1 to 4, which is a compound represented by
   

   
6. Wherein _[1], the liquid crystal alignment agent according to claim 5 neither X 1, _{X 2} and _{X 3} represents a hydroxyalkyl group.
7. A liquid crystal alignment film obtained by using the liquid crystal aligning agent according to any one of claims 1 to 6.
8. A liquid crystal display element having the liquid crystal alignment film according to claim 7.