JP6870289B2 - Liquid crystal alignment agent, manufacturing method of liquid crystal element, liquid crystal alignment film, liquid crystal element - Google Patents

Description

The present invention relates to a liquid crystal aligning agent, a method of manufacturing a liquid crystal device, a liquid crystal alignment film, relates to a liquid crystal element.

Conventionally, as a liquid crystal display element, various drive methods having different electrode structures and physical properties of liquid crystal molecules used have been developed. For example, TN type, STN type, VA type, in-plane switching type (IPS type) and the like have been developed. Various liquid crystal display elements are known. These liquid crystal display elements have a liquid crystal alignment film for orienting liquid crystal molecules. As the material of the liquid crystal alignment film, for example, polyamic acid, polyamic acid ester, polyimide, polyester, polyorganosiloxane and the like are known.

Further, in recent years, a PSA (Polymer Unified Alignment) mode has been proposed as a new drive mode for controlling the orientation of liquid crystal molecules in a liquid crystal display element. In the PSA mode, a photopolymerizable compound is mixed in a liquid crystal material, the liquid crystal cell is assembled, and then the liquid crystal cell is irradiated with light while a voltage is applied between a pair of electrodes sandwiching the liquid crystal layer. This is a technique for controlling the molecular orientation of liquid crystal molecules by polymerizing a polymerizable compound. According to this technology, there are advantages that the viewing angle can be expanded and high-speed response can be achieved.

On the other hand, in the PSA mode, when the light irradiation amount is insufficient, the unreacted photopolymerizable compound remains in the liquid crystal layer, and the unreacted substance tends to cause burn-in (afterimage) of the image. Further, if the amount of light irradiation is increased in order to completely react the photopolymerizable compound, the quality of the liquid crystal molecules and the liquid crystal alignment film may deteriorate, and the display quality of the panel may deteriorate. In order to eliminate such inconvenience, various techniques for reducing the amount of the photopolymerizable compound remaining in the liquid crystal layer without increasing the amount of light irradiation have been proposed (see, for example, Patent Document 1). Patent Document 1 discloses that a liquid crystal compound having a terphenyl ring structure (hereinafter, also referred to as "terphenyl-based liquid crystal") is contained in a liquid crystal layer.

Further, in recent years, further high-speed response of PSA type liquid crystal panels has been studied, and as such a technique, a monofunctional liquid crystal compound having one of an alkenyl group and a fluoroalkenyl group (hereinafter, "alkenyl"). Attempts have been made to introduce (also referred to as "system liquid crystal") into the liquid crystal layer (see, for example, Patent Documents 2 to 4).

International Publication No. 2009/050869 Japanese Unexamined Patent Publication No. 2010-285499 Japanese Unexamined Patent Publication No. 9-104644 Japanese Unexamined Patent Publication No. 6-108053

However, even when the terphenyl liquid crystal is introduced into the liquid crystal layer, there are still many unreacted photopolymerizable compounds remaining after light irradiation, and there is room for further improvement in terms of afterimage characteristics. Further, in the liquid crystal display element using the alkenyl liquid crystal, the response speed can be increased, but the voltage retention rate is higher than that of the liquid crystal cell in which the alkenyl liquid crystal is not contained in the liquid crystal layer due to the irradiation of the liquid crystal cell with light. It has been clarified that the decrease in the liquid crystal becomes large. From the viewpoint of further improving the display quality of the liquid crystal display element, it is required to suppress the decrease in the voltage retention rate due to light irradiation as much as possible.

The present invention has been made in view of the above problems, and a main object of the present invention is to provide a liquid crystal aligning agent capable of obtaining a liquid crystal display element capable of exhibiting a high voltage retention rate even after irradiating a liquid crystal cell with light and hardly causing an afterimage. And.

As a result of diligent studies to achieve the above-mentioned problems of the prior art, the present inventors have made a group consisting of a polysiloxane having a specific partial structure and a polyamic acid, a polyamic acid ester, a polyimide, and a polyamide having a specific partial structure. We have found that the above problems can be solved by a liquid crystal aligning agent containing at least one polymer selected from the above, and have completed the present invention. Specifically, the present invention provides the following liquid crystal alignment agent, a method for producing a liquid crystal element, a liquid crystal alignment film, a liquid crystal element, and a polymer. Specifically, the following means are provided.
<1> A polysiloxane having at least one partial structure selected from the group represented by the following formulas (1) and the following formulas (2) to (9), and
Selected from the group consisting of polyamic acid, polyamic acid ester, polyimide, and polyamide, and selected from the groups represented by the following formulas (1-1), the following formulas (1-2), and the following formulas (2) to (9). Polymers with at least one partial structure,
A liquid crystal alignment agent containing at least one polymer selected from the group consisting of.

(In equations (1) to (9),
X independently represents a halogen atom, a hydroxyl group, a cyano group, a nitro group, an alkyl group having 1 to 6 carbon atoms, and an alcoholic group having 1 to 6 carbon atoms.
a is an integer from 0 to 4, b is an integer from 0 to 3, c is an integer from 0 to 5, and so on.
R ₁ , R ₂ , R ₄ , R ₅ , R ₆ , R ₇ and R ₈ independently have a hydrogen atom, a halogen atom, a hydroxyl group, an alkyl group having 1 to 20 carbon atoms, and 1 to 20 carbon atoms. the alkoxy group, an aryl group having 6 to 30 carbon atoms, an aryl alkyl group having 7 to 30 carbon atoms, an alkenyl group having 2 to 12 carbon atoms, an alkenyloxy group having 2 to 12 carbon atoms, _{R 1} And R ₂ may be linked to form a 3- to 6-membered cyclic alkane or heterocyclic group, such as an alkyl group, an alcohol group, an aryl group, an arylalkyl group, an alkenyl group, an alkenyloxy group, a cyclic alkyl group, The heterocyclic group may have a substituent and may have a substituent.
R ₃ represents a hydroxyl group, an alkyl group having 1 to 20 carbon atoms substituted or substituted, or any group represented by the following formula (10), and the alkoxy group may have a substituent.

(In formula (10), Y ₂ is a methylene group, -NR, an oxygen atom, and a sulfur atom, R is an independent hydrogen atom and an alkyl group having 1 to 4 carbon atoms, and X and c are the above. Is the same as.)
* Represents a bond. )

In (Equation (1-1), (Equation 1-2),
X, a, R ₁ , R ₂ , R ₃ , * are the same as above.
d is an integer from 1 to 5
R ₉ and R ₁₀ are independently hydrogen atom, halogen atom, hydroxyl group, alkyl group having 1 to 20 carbon atoms, alcoholic group having 1 to 20 carbon atoms, aryl group having 6 to 30 carbon atoms, and carbon atom. arylalkyl group having 7 to 30, an alkenyl group having 2 to 12 carbon atoms, represents alkenyloxy group having 2 to 12 carbon atoms, _{R 1} and _{R 2} are cyclic alkanes having 3 to 6-membered ring by combining or A heterocyclic group may be formed, and the alkyl group, the alcoholic group, the aryl group, the arylalkyl group, the alkenyl group, the alkenyloxy group, the cyclic alkyl group and the heterocyclic group may have a substituent.
At _{least one selected from the group of R 9} and R ₁₀ represents a hydrogen atom, a halogen atom, a hydroxyl group, an alkenyl group having 2 to 12 carbon atoms, and an alkenyloxy group having 2 to 12 carbon atoms. )
A step of applying the liquid crystal alignment agent of <1> above on the conductive film of a pair of substrates having a conductive film to form a coating film.
A step of constructing a liquid crystal cell by arranging a pair of substrates on which the coating film is formed so as to face each other with the coating film facing each other via a liquid crystal layer.
A method for manufacturing a liquid crystal element, comprising a step of irradiating the liquid crystal cell with light in a state where a voltage is applied between the conductive films of the pair of substrates.

By producing a liquid crystal alignment film using the above liquid crystal alignment agent, a high voltage retention rate can be exhibited even after light irradiation of the liquid crystal cell, and afterimages are less likely to occur. Further, in the obtained liquid crystal display element, the response speed of the liquid crystal molecules is fast, and the display quality can be improved.

The figure which shows the electrode pattern of the transparent electrode film used in an Example and a comparative example. The figure which shows the electrode pattern of the transparent electrode film used in an Example and a comparative example. The figure which shows the electrode pattern of the transparent electrode film used in an Example and a comparative example.

Hereinafter, each component contained in the liquid crystal alignment agent of the present disclosure, and other components optionally blended will be described.

In addition, in this specification, the "main chain" of a polymer means the part of the "stem" which consists of the longest chain of atoms in a polymer. It is permissible for this "trunk" portion to include a ring structure. "Hydrocarbon group" is a concept including a chain hydrocarbon group, an alicyclic hydrocarbon group and an aromatic hydrocarbon group. The "chain hydrocarbon group" means a linear or branched hydrocarbon group which does not contain a cyclic structure and is composed only of a chain structure. The "alicyclic hydrocarbon group" means a hydrocarbon group containing only the alicyclic hydrocarbon structure as the ring structure. However, it does not have to be composed only of the alicyclic hydrocarbon structure, and may have a chain structure as a part thereof. The "aromatic hydrocarbon group" means a hydrocarbon group containing an aromatic ring structure as a ring structure. However, it does not have to be composed of only an aromatic ring structure, and a chain structure or an alicyclic hydrocarbon structure may be included in a part thereof.
<Polymer (A)>
The polymer (A) is a polysiloxane having at least one partial structure selected from the group represented by the above formula (1) and the above formulas (2) to (9), and
Selected from the group consisting of polyamic acid, polyamic acid ester, polyimide, and polyamide, and selected from the groups represented by the above formulas (1-1), the above formulas (1-2), and the above formulas (2) to (9). A polymer, which has at least one partial structure.
A polysiloxane having at least one partial structure selected from the groups represented by the above formulas (1), (3), (4) and (5), and
It is selected from the group consisting of polyamic acid, polyamic acid ester, polyimide, and polyamide, and is represented by the above formulas (1-1), (1-2), and formulas (3), (4), and (5). It is preferably a polymer having at least one partial structure selected from the group.
As the polymer (A), one type may be used alone, or two or more types may be used in combination.
The substituent of the alkyl group, arcosiki group, alkenyl group, alkenyloxy group, cyclic alkyl group or heterocyclic group may be a hydroxyl group, a carboxyl group, a halogen atom, a cyano group or a nitro group.
The substituent of the aryl group may be an alkyl group having 1 to 4 carbon atoms, a hydroxyl group, a carboxyl group, a halogen atom, a cyano group or a nitro group.
Examples of the substituent of the arylalkyl group include an alkyl group having 1 to 4 carbon atoms, a hydroxyl group, an alkoxy group having 1 to 4 carbon atoms, an amino group, an alkylthio group having 1 to 4 carbon atoms, a carboxyl group and a halogen atom. It may be a cyano group or a nitro group.
The alkyl group, alkoxy group, alkenyl group and cyclic alkyl group may have a branched structure.
Examples of the alkyl group having 1 to 20 carbon atoms include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, s-butyl, t-butyl, amyl, isoamyl, t-amyl, hexyl, heptyl, octyl, isooctyl, and the like. Examples thereof include 2-ethylhexyl, t-octyl, nonyl, isononyl, decyl, isodecyl, undecyl, dodecyl, tetradecyl, hexadecyl, octadecyl, icosyl, cyclopentyl, cyclopentylmethyl, cyclopentylethyl, cyclohexyl, cyclohexylmethyl and cyclohexylethyl.
Examples of the alcoholic group having 1 to 20 carbon atoms include methoxy, ethoxy, propyloxy, isopropyloxy, butoxy and the like.
Examples of the aryl group having 6 to 30 carbon atoms include a phenyl group, a naphthyl group, a biphenylene group and the like.
Examples of the arylalkyl group having 7 to 30 carbon atoms include benzyl, α-methylbenzyl, α, α-dimethylbenzyl, phenylethyl, 9-fluorenylmethyl and the like.
Examples of the alkenyl group having 2 to 12 carbon atoms include a vinyl group, a 1-propenyl group, a 2-propenyl group, an isopropenyl group, a 1-butenyl group, a 2-butenyl group, a 3-butenyl group, a 1-octenyl group and 1 -Groups such as a decenyl group can be mentioned.
Examples of the alkenyloxy group having 2 to 12 carbon atoms include a vinyloxy group and a 1-propenyloxy group.
Examples of the 3- to 6-membered cyclic alkane include a cyclopentane ring and a cyclohexane ring.
Examples of the heterocyclic group include a group in which one of the carbon atoms of the cyclic alkane is replaced with a nitrogen atom.
[Polyorganosiloxane]
A polysiloxane having at least one partial structure selected from the group represented by the above formula (1) and the above formulas (2) to (9) as the polymer (A) (hereinafter, also referred to as "polyorganosiloxane (A)"). ) Can be obtained, for example, by hydrolyzing and condensing a hydrolyzable silane compound. Specifically, the following [1] or [2] can be mentioned.
[1] An epoxy group-containing polyorganosiloxane is synthesized by hydrolyzing and condensing a hydrolyzable silane compound (ms-1) having an epoxy group or a mixture of the silane compound (ms-1) and another silane compound. Then, the obtained epoxy group-containing polyorganosiloxane and a carboxylic acid having at least one partial structure selected from the groups represented by the above formulas (1) and the above formulas (2) to (9) (hereinafter, "" A method of reacting with "specific carboxylic acid"),
[2] Group A hydrolyzable silane compound (ms-2) having at least one partial structure selected from the group represented by the above formula (1) and the above formulas (2) to (9), or the silane compound. Examples thereof include a method of hydrolyzing and condensing a mixture of (ms-2) and another silane compound. Of these, the method [1] is simple and has at least one partial structure selected from the groups represented by the above formulas (1) and the above formulas (2) to (9) in the polyorganosiloxane. It is preferable in that the introduction rate can be increased.

Specific examples of the silane compound (ms-1) include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, and 3-glycidoxypropyl. Methyldiethoxysilane, 2- (3,4-epylcyclohexyl) ethyltrimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltriethoxysilane, 3- (3,4-epylcyclohexyl) propyltrimethoxysilane, etc. Can be mentioned. As the silane compound (ms-1), one of these can be used alone or in combination of two or more.

Specific examples of the silane compound (ms-2) include compounds represented by the following formulas and the like.

As the silane compound (ms-2), one of these can be used alone or in combination of two or more.

Other silane compounds are not particularly limited as long as they are hydrolyzable silane compounds, and are, for example, tetramethoxysilane, tetraethoxysilane, methyltrimethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, dimethyldimethoxysilane, and dimethyl. Alkoxysilanes such as diethoxysilanes;
3-Mercaptopropyltrimethoxysilane, 3-Mercaptopropyltriethoxysilane, 3-ureidopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N- (3-cyclohexylamino) propyltri Nitrogen / sulfur-containing alkoxysilanes such as methoxysilane and N-2- (aminoethyl) -3-aminopropyltrimethoxysilane;
3- (Meta) acryloyloxypropyltrimethoxysilane, 3- (meth) acryloyloxypropyltriethoxysilane, 6- (meth) acryloyloxyhexyltrimethoxysilane, 3- (meth) acryloyloxypropylmethyldimethoxysilane, 3- (Meta) alkoxysilanes containing unsaturated bonds such as acryloxipropylmethyldiethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, p-styryltrimethoxysilane; and trimethoxysilylpropylsuccinate anhydride. Can be mentioned. Other silane compounds may be used alone or in combination of two or more.

The hydrolysis / condensation reaction of the silane compound is carried out by reacting one or more of the above silane compounds with water, preferably in the presence of a suitable catalyst and organic solvent.

In the method of the above [1], a sufficient amount of the basic partial structure selected from the group represented by the above formulas (1) and the above formulas (2) to (9) is introduced into the side chain of the polymer. The epoxy equivalent of the epoxy group-containing polyorganosiloxane is preferably 100 to 10,000 g / mol, preferably 150, from the viewpoint of suppressing side reactions caused by an excessive amount of epoxy groups while enabling the above. More preferably, it is ~ 1,000 g / mol. Therefore, in synthesizing the epoxy group-containing polyorganosiloxane, it is preferable to adjust the usage ratio of the silane compound (ms-1) so that the epoxy equivalent of the obtained polyorganosiloxane is within the above range. In the hydrolysis / condensation reaction, the ratio of water used is preferably 0.5 to 100 mol, more preferably 1 to 30 mol, based on 1 mol of the silane compound (total amount).

Examples of the catalyst used in the hydrolysis / condensation reaction include acids, alkali metal compounds, organic bases, titanium compounds, and zirconium compounds. The amount of the catalyst used varies depending on the type of catalyst, reaction conditions such as temperature, and should be set appropriately, but is preferably 0.01 to 3 times the molar amount of the total amount of the silane compound, for example. , More preferably 0.05 to 1 times the molar amount.

Examples of the organic solvent used in the above hydrolysis / condensation reaction include hydrocarbons, ketones, esters, ethers, alcohols and the like. Of these, it is preferable to use a water-insoluble or poorly water-soluble organic solvent. The proportion of the organic solvent used is preferably 10 to 10,000 parts by weight, more preferably 50 to 1,000 parts by weight, based on 100 parts by weight of the total silane compound used in the reaction.

The above hydrolysis / condensation reaction is preferably carried out by heating in, for example, an oil bath. During the hydrolysis / condensation reaction, the heating temperature is preferably 130 ° C. or lower, more preferably 40 to 100 ° C. The heating time is preferably 0.5 to 12 hours, more preferably 1 to 8 hours. During heating, the mixture may be agitated or placed under reflux. Further, after the reaction is completed, it is preferable to wash the organic solvent layer separated from the reaction solution with water. In this cleaning, it is preferable to use water containing a small amount of salt (for example, an aqueous solution of ammonium nitrate of about 0.2% by weight) to facilitate the cleaning operation. The washing is carried out until the water layer after washing becomes neutral, and then the organic solvent layer is dried with a desiccant such as anhydrous calcium sulfate or molecular sieve, and then the solvent is removed. The polyorganosiloxane to be obtained can be obtained. The method for synthesizing polyorganosiloxane is not limited to the above-mentioned hydrolysis / condensation reaction, and may be carried out by, for example, a method of reacting a hydrolyzable silane compound in the presence of oxalic acid and alcohol.

In the method of the above [1], the epoxy group-containing polyorganosiloxane obtained by the above reaction is then reacted with a specific carboxylic acid. As a result, the epoxy group contained in the epoxy group-containing polyorganosiloxane reacts with the carboxylic acid, and at least one partial structure selected from the groups represented by the above formulas (1) and the above formulas (2) to (9) is selected. Can be obtained as a polyorganosiloxane having the above in the side chain.

Specific examples of the specific carboxylic acid include compounds represented by each of the following formulas.

The specific carboxylic acid may be used alone or in combination of two or more.

The content ratio of at least one partial structure selected from the groups represented by the above formulas (1) and the above formulas (2) to (9) in one molecule of polyorganosiloxane fully exerts the effect of the present invention. From this point of view, it is preferably 3 to 80 mol%, more preferably 5 to 75 mol%, and further preferably 10 to 70 mol% with respect to the silicon atom of the polyorganosiloxane. .. Therefore, when synthesizing the polyorganosiloxane (A), the content ratio of at least one partial structure selected from the groups represented by the above formulas (1) and the above formulas (2) to (9) is within the above range. It is preferable to select the ratio of the specific carboxylic acid used.

In the synthesis of polyorganosiloxane (A), the carboxylic acid used in the reaction with the epoxy group-containing polyorganosiloxane may be only the specific carboxylic acid, but other carboxylic acids other than the specific carboxylic acid may be used in combination. Good.

The other carboxylic acid is not particularly limited as long as it is a carboxylic acid that does not have at least one partial structure selected from the groups represented by the above formulas (1) and (2) to (9). Examples thereof include a carboxylic acid having the above liquid crystal orientation group. Other carboxylic acids may be used alone or in combination of two or more.

The ratio of the carboxylic acid to be reacted with the epoxy group-containing polyorganosiloxane is preferably 0.001 to 1.5 mol, preferably 0.01 to 1 mol, based on 1 mol of the total epoxy groups of the polyorganosiloxane. More preferably, it is 0.0 mol.

The ratio of other carboxylic acids used is preferably 80 mol% or less, more preferably 50 mol% or less, based on the total amount of carboxylic acids to be reacted with the epoxy group-containing polyorganosiloxane.

The reaction of the epoxy group-containing polysiloxane with the carboxylic acid can preferably be carried out in the presence of a catalyst and an organic solvent. As the catalyst, for example, a compound known as a so-called curing accelerator that promotes the reaction of an organic base or an epoxy compound can be used. Of these, tertiary organic amines or quaternary organic amines are preferred. The ratio of the catalyst used is preferably 100 parts by weight or less, more preferably 0.01 to 100 parts by weight, still more preferably 0.1 to 20 parts by weight, based on 100 parts by weight of the epoxy group-containing polysiloxane.

Examples of the organic solvent used in the above reaction include hydrocarbons, ethers, esters, ketones, amides, alcohols and the like. Among these, from the viewpoint of solubility of raw materials and products and ease of purification of products, at least one selected from the group consisting of ethers, esters and ketones is preferable, and specific examples of particularly preferable solvents. Examples thereof include 2-butanone, 2-hexanone, methyl isobutyl ketone and butyl acetate. The organic solvent is preferably used in a proportion such that the solid content concentration (the ratio of the total weight of the components other than the solvent in the reaction solution to the total weight of the solution) is 0.1% by weight or more. It is more preferable to use it in a ratio of 5 to 50% by weight.

The reaction temperature in the above reaction is preferably 0 to 200 ° C, more preferably 50 to 150 ° C. The reaction time is preferably 0.1 to 50 hours, more preferably 0.5 to 20 hours. Further, after the reaction is completed, it is preferable to wash the organic solvent layer separated from the reaction solution with water. After washing with water, the organic solvent layer is dried with an appropriate desiccant if necessary, and then the solvent is removed to select from the groups represented by the above formulas (1) and the above formulas (2) to (9). A polyorganosiloxane having at least one partial structure in the side chain can be obtained.

For the polyorganosiloxane (A), the polystyrene-equivalent weight average molecular weight (Mw) measured by GPC is preferably in the range of 100 to 50,000, more preferably in the range of 200 to 10,000. When the weight average molecular weight of the polyorganosiloxane (A) is in the above range, it is easy to handle when producing a liquid crystal alignment film, and the obtained liquid crystal alignment film has sufficient material strength and properties.
[Polyamic acid]
A polyamic acid having at least one partial structure selected from the group represented by the above formula (1-1), the above formula (1-2) and the above formulas (2) to (9) as the polymer (A) ( Hereinafter, "polyamic acid (A)") is represented by, for example, tetracarboxylic dianhydride and the above formula (1-1), the above formula (1-2) and the above formulas (2) to (9). It can be obtained by reacting with a diamine having at least one partial structure selected from the above group.
(Tetracarboxylic dianhydride)
Examples of the tetracarboxylic dianhydride used for the synthesis of the polyamic acid (A) include an aliphatic tetracarboxylic dianhydride, an alicyclic tetracarboxylic dianhydride, and an aromatic tetracarboxylic dianhydride. be able to. Specific examples of these include aliphatic tetracarboxylic dianhydrides such as 1,2,3,4-butanetetracarboxylic dianhydride;
Examples of the alicyclic tetracarboxylic dianhydride include 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentylacetic acid dianhydride, 5- (2,5-di). Oxotetrahydrofuran-3-yl) -3a,4,5,9b-tetrahydronaphtho [1,2-c] furan-1,3-dione, 5- (2,5-dioxo tetrahydrofuran-3-yl) -8 -Methyl-3a, 4,5,9b-tetrahydronaphtho [1,2-c] furan-1,3-dione, 3-oxabicyclo [3.2.1] octane-2,4-dione-6-spiro -3'-(tetrahydrofuran-2', 5'-dione), 5- (2,5-dioxotetrahydro-3-furanyl) -3-methyl-3-cyclohexene-1,2-dicarboxylic dianhydride, 3 , 5,6-tricarboxy-2-carboxymethylnorbornane-2: 3,5: 6-dianhydride, 2,4,6,8-tetracarboxybicyclo [3.3.0] octane-2: 4, 6: 8-dianhydride, 4,9-dioxatricyclo [5.3.1.0 ^2,6 ] undecane-3,5,8,10-tetraone, cyclohexanetetracarboxylic dianhydride, etc.;
Examples of the aromatic tetracarboxylic dianhydride include pyromellitic dianhydride, 4,4'-(hexafluoroisopropyridene) diphthalic anhydride, and the following formula (B-1).

(In the formula ^{(B-1), X} 1 and ^{X 2} are each independently a single bond, an oxygen atom, a sulfur atom, -CO -, * - COO - , * - OCO -, * - CO-NR 22 -, * -NR ^22- CO- (where R ²² is a hydrogen atom or a monovalent hydrocarbon group having 1 to 6 carbon atoms. "*" Indicates a bond with ^{R 21). Reference numeral 21} denotes an alcandiyl group having 1 to 10 carbon atoms, a divalent group containing —O— between carbon-carbon bonds of the alcandiyl group, a cyclohexylene group, a phenylene group, or a biphenylene group).
In addition to the above, the tetracarboxylic dianhydride described in JP-A-2010-97188 can be used.

Specific examples of the alkanediyl group having 1 to 10 carbon atoms R ²¹ in the above formula (B-1), such as methylene group, ethylene group, propylene group, butanediyl group, pentanediyl group, hexanediyl group, Heputanjiiru group, octane Examples thereof include a diyl group, a nonane diyl group and a decandiyl group. In a divalent group containing -O- between carbon-carbon bonds of an alkanediyl group, the number of oxygen atoms may be one or two or more.

Specific examples of the compound represented by the above formula (B-1) include compounds represented by each of the following formulas (B-1-1) to (B-1--4).

The tetracarboxylic dianhydride may be used alone or in combination of two or more.

The tetracarboxylic dianhydride used for the synthesis includes 1,2,3,4-cyclobutanetetracarboxylic dianhydride and 2,3,5-tricarboxycyclopentyl dianhydride from the viewpoint of compatibility with liquid crystal. Anhydrous, 5- (2,5-dioxo tetrahydrofuran-3-yl) -3a,4,5,9b-tetrahydronaphtho [1,2-c] furan-1,3-dione, 5- (2,5) −Dioxo tetrahydrofuran-3-yl) -8-methyl-3a, 4,5,9b-tetrahydronaphtho [1,2-c] furan-1,3-dione, bicyclo [3.3.0] octane-2 , 4,6,8-tetracarboxylic dianhydride, cyclopentanetetracarboxylic dianhydride, cyclohexanetetracarboxylic dianhydride, p-phenylenebis (trimellitic acid monoester anhydride), pyromellitic dianhydride It is preferable to contain at least one compound selected from the group consisting of the substance and the compound represented by the above formula (B-1). The amount of these preferable tetracarboxylic dianhydrides used (the total amount when two or more kinds are used) is 5 mol% or more based on the total amount of the tetracarboxylic dianhydride used for the synthesis of polyamic acid. It is preferably 10 mol% or more, and more preferably 20 mol% or more.
(Diamine)
It has at least one partial structure selected from the groups represented by the above formulas (1-1), the above formulas (1-2) and the above formulas (2) to (9) used for the synthesis of the polyamic acid (A). Diamine (hereinafter sometimes referred to as specific diamine)
Specific examples of the above include, for example, compounds represented by the following formulas and the like.

In the synthesis of the polyamic acid (A), the specific diamine may be used alone, or a diamine other than the specific diamine (hereinafter referred to as "other diamine") may be used in combination.

Examples of such other diamines include aliphatic diamines, alicyclic diamines, aromatic diamines, and diaminoorganosiloxane. Specific examples of these diamines include, as aliphatic diamines, m-xylylenediamine, 1,3-propanediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, 1,3-bis (aminomethyl) cyclohexane and the like. ;
As the alicyclic diamine, for example, 1,4-diaminocyclohexane, 4,4'-methylenebis (cyclohexylamine) and the like;
As aromatic diamines, for example, dodecanoxidiaminobenzene, tetradecanoxidiaminobenzene, pentadecanoxidiaminobenzene, hexadecanoxidiaminobenzene, octadecanoxidiaminobenzene, 3,5-diaminobenzoic acid 2- ( Methacryloyloxy) Ethyl, Cholestanyloxydiaminobenzene, Cholesteryloxydiaminobenzene, Cholestanyl diaminobenzoate, Cholesteryl diaminobenzoate, Ranostanyl diaminobenzoate, 3,6-bis (4-aminobenzoyloxy) cholestan, 3,6-bis (4-Aminophenoxy) Cholestan, 1,1-bis (4-((aminophenyl) methyl) phenyl) -4-butylcyclohexane, 1,1-bis (4-((aminophenyl) methyl) phenyl) -4 −Heptylcyclohexane, 1,1-bis (4-((aminophenoxy) methyl) phenyl) -4-heptylcyclohexane, N- (2,4-diaminophenyl) -4- (4-heptylcyclohexyl) benzamide, the following formula (E-1)

(In the formula (E-1), X ^I and X ^II are independently single-bonded, -O-, * -COO- or * -OCO- (where "*" is a bond with ^{X I.} shown.), and, ^{R I} is an alkanediyl group having 1 to 3 carbon ^{atoms, R II} is a single bond or an alkanediyl group having 1 to 3 carbon atoms, a is 0 or 1, b is 0 It is an integer of ~ 2, c is an integer of 1 to 20, d is 0 or 1. However, a and b cannot be 0 at the same time.)
Orientation group-containing diamines such as compounds represented by:
p-phenylenediamine, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylsulfide, 4-aminophenyl-4'-aminobenzoate, 4,4'-diaminoazobenzene, 3,5-diaminobenzoic acid, 2 , 4-Diaminobenzoic acid, 2,6-diaminopyridine, 1,5-bis (4-aminophenoxy) pentane, 1,7-bis (4-aminophenoxy) heptane, bis [2- (4-aminophenyl) Ethyl] hexanedioic acid, N, N-bis (4-aminophenyl) methylamine, 2,2'-dimethyl-4,4'-diaminobiphenyl, 2,2'-bis (trifluoromethyl) -4,4 '-Diaminobiphenyl, 2,7-diaminofluorene, 4,4'-diaminodiphenyl ether, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 9,9-bis (4-aminophenyl) fluorene , 2,2-bis [4- (4-aminophenoxy) phenyl] hexafluoropropane, 4,4'-(p-phenylenediisopropylidene) bisaniline, 1,4-bis (4-aminophenoxy) benzene, 4 , 4'-bis (4-aminophenoxy) biphenyl, etc .;
Examples of the diaminoorganosiloxane include 1,3-bis (3-aminopropyl) -tetramethyldisiloxane; and the diamine described in JP-A-2010-97188 can be used.

In the above formula (E-1) ^{"-X I - (R I -X II} ) d - " Examples of the divalent group represented by the alkanediyl group having 1 to 3 carbon atoms, * - O -, * -COO- or _{* -O-C 2 H 4 -O-} ( where bond marked with "*" is bonded to the diamino phenyl group.) is preferably. Examples of the group "-C _c H _{2c + 1} " include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group, a dodecyl group, a tridecyl group and a tetradecyl group. Examples thereof include a group, a pentadecyl group, a hexadecyl group, a heptadecyl group, an octadecyl group, a nonadecil group, an eikosyl group and the like, and these are preferably linear. The two amino groups in the diaminophenyl group are preferably at the 2,4- or 3,5-position with respect to the other groups.

Specific examples of the compound represented by the above formula (E-1) include compounds represented by each of the following formulas (E-1-1) to (E-1--4).

When applied to a liquid crystal alignment agent for a TN type, STN type or vertically oriented type liquid crystal display element, a group capable of exhibiting a property of controlling the orientation of liquid crystal molecules in the side chain of the polyamic acid (hereinafter referred to as "liquid crystal orientation group"). Also called.) May be introduced. Examples of the liquid crystal oriented group include an alkyl group having 4 to 20 carbon atoms, a fluoroalkyl group having 4 to 20 carbon atoms, an alkoxy group having 4 to 20 carbon atoms, a group having a steroid skeleton having 17 to 51 carbon atoms, and a polycyclic ring. Examples thereof include groups having a structure. The polyamic acid having a liquid crystal oriented group can be obtained, for example, by polymerization containing an oriented group-containing diamine in the monomer composition. When an orientation group-containing diamine is used, the blending amount thereof is preferably 3 mol% or more, preferably 5 to 70 mol%, based on the total diamine used for synthesis from the viewpoint of liquid crystal orientation. Is more preferable.

When the liquid crystal alignment ability is imparted to the coating film formed by the liquid crystal alignment agent by the photoalignment method, at least a part of the polyamic acid (A) may be a polymer having a photoalignment structure. As a specific example of the photo-orientation structure, a group exhibiting photo-orientation by photoisomerization, photodimerization, photodecomposition or the like can be adopted. Specifically, for example, an azo-containing group containing an azo compound or a derivative thereof as a basic skeleton, a katsura acid-containing group containing katsura acid or a derivative thereof as a basic skeleton, and a chalcone-containing group containing calcon or a derivative thereof as a basic skeleton. , A benzophenone-containing group containing benzophenone or a derivative thereof as a basic skeleton, a coumarin-containing group containing coumarin or a derivative thereof as a basic skeleton, a cyclobutane-containing structure containing cyclobutane or a derivative thereof as a basic skeleton, bicyclo [2.2.2 ] Bicyclo containing octene or a derivative thereof as a basic skeleton [2.2.2] Octen-containing structure, the following formula (4)

(In formula (4), X ⁴ is a sulfur atom, an oxygen atom or -NH-. "*" Indicates a bond, respectively. However, at least one of the two "*" is bonded to an aromatic ring. doing.)
Examples thereof include an ester group-containing structure containing a partial structure represented by (1) as a basic skeleton.

The polyamic acid having a photo-oriented structure can be obtained by polymerization containing at least one of a tetracarboxylic dianhydride having a photo-oriented structure and a diamine having a photo-oriented structure as raw materials. In this case, the ratio of the monomer having a photo-oriented structure is preferably 20 mol% or more with respect to the total amount of the monomer used for the synthesis of polyamic acid from the viewpoint of improving the photoreactivity. More preferably, it is ~ 80 mol%.

In the synthesis of the polyamic acid (A), the ratio of the specific diamine used may be 1 mol% or more with respect to the total amount of diamines used in the synthesis from the viewpoint of sufficiently exerting the effect of the present invention. It is preferably 5 mol% or more, more preferably 10 mol% or more. The upper limit of the usage ratio of the specific diamine is not particularly limited, but when other diamines are used, it is preferably 90 mol% or less, and more preferably 80 mol% or less.
(Synthesis of polyamic acid)
The polyamic acid can be obtained by reacting the tetracarboxylic dianhydride as described above with a diamine, if necessary, with a molecular weight regulator. The ratio of tetracarboxylic acid dianhydride and diamine used in the polyamic acid synthesis reaction is 0.2 to 2 for the acid anhydride group of tetracarboxylic acid dianhydride with respect to 1 equivalent of the amino group of the diamine. The ratio of equivalents is preferable, and the ratio of 0.3 to 1.2 equivalents is more preferable.

Examples of the molecular weight adjusting agent include acid monoanhydrides such as maleic anhydride, phthalic anhydride and itaconic anhydride, monoamine compounds such as aniline, cyclohexylamine and n-butylamine, and monoisocyanate compounds such as phenylisocyanate and naphthylisocyanate. Can be mentioned. The ratio of the molecular weight adjusting agent used is preferably 20 parts by weight or less, and more preferably 10 parts by weight or less, based on 100 parts by weight of the total of the tetracarboxylic dianhydride and the diamine used.

The polyamic acid synthesis reaction is preferably carried out in an organic solvent. The reaction temperature at this time is preferably −20 ° C. to 150 ° C., more preferably 0 to 100 ° C. The reaction time is preferably 0.1 to 24 hours, more preferably 0.5 to 12 hours.

Examples of the organic solvent used in the reaction include an aprotic polar solvent, a phenolic solvent, an alcohol, a ketone, an ester, an ether, a halogenated hydrocarbon, and a hydrocarbon. Among these organic solvents, one or more selected from the group consisting of an aprotic polar solvent and a phenolic solvent (organic solvent of the first group), or one or more selected from the organic solvent of the first group. It is preferable to use a mixture of one or more selected from the group consisting of alcohols, ketones, esters, ethers, halogenated hydrocarbons and hydrocarbons (organic solvents of the second group). In the latter case, the proportion of the organic solvent used in the second group is preferably 50% by weight or less, more preferably 40% by weight, based on the total amount of the organic solvent in the first group and the organic solvent in the second group. It is less than or equal to, more preferably 30% by weight or less.

Particularly preferred organic solvents are N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, dimethyl sulfoxide, γ-butyrolactone, tetramethylurea, hexamethylphosphortriamide, m-cresol, xylenol. It is preferable to use one or more selected from the group consisting of and halogenated phenol as a solvent, or to use a mixture of one or more of these and another organic solvent in the above ratio range. Examples of other organic solvents used at this time include butyl cellosolve, 2-butoxy-1-propanol, diethylene glycol diethyl ether and the like. The amount of the organic solvent used (a) shall be such that the total amount (b) of the tetracarboxylic dianhydride and the diamine is 0.1 to 50% by weight based on the total amount (a + b) of the reaction solution. Is preferable.

As described above, a reaction solution obtained by dissolving a polyamic acid is obtained. This reaction solution may be used as it is for the preparation of the liquid crystal alignment agent, the polyamic acid contained in the reaction solution may be isolated and then used for the preparation of the liquid crystal alignment agent, or the isolated polyamic acid may be purified. Then, it may be used for the preparation of the liquid crystal aligning agent. Isolation and purification of the polyamic acid can be carried out according to a known method.
[Polyamic acid ester]
The polyamic acid ester as the polymer (A) is, for example, [I] a method of reacting the polyamic acid (A) obtained by the above synthesis reaction with an esterifying agent, [II] a tetracarboxylic dian diester and a diamine. It can be obtained by a method of reacting, a method of reacting a [III] tetracarboxylic dianester dihalide with a diamine, or the like.

In the present specification, the "tetracarboxylic dianester" means a compound in which two of the four carboxyl groups of the tetracarboxylic acid are esterified and the remaining two are carboxyl groups. The "tetracarboxylic dianester dihalogenate" means a compound in which two of the four carboxyl groups of the tetracarboxylic acid are esterified and the remaining two are halogenated.

Examples of the esterifying agent used in the method [I] include hydroxyl group-containing compounds, acetal-based compounds, halides, and epoxy group-containing compounds. Specific examples of these include, for example, alcohols such as methanol, ethanol and propanol, and phenols such as phenol and cresol as hydroxyl group-containing compounds; for example, N, N-dimethylformamide diethyl acetal, N, as acetal compounds. N-diethylformamide diethylacetal, etc .; as halides, for example, methyl bromide, ethyl bromide, stearyl bromide, methyl chloride, stearyl chloride, 1,1,1-trifluoro-2-iodoethane, etc .; containing epoxy groups. Examples of the compound include propylene oxide and the like.

The tetracarboxylic dianhydride used in the method [II] can be obtained, for example, by opening the ring of the tetracarboxylic dianhydride exemplified in the synthesis of the polyamic acid with alcohols such as methanol and ethanol. The tetracarboxylic acid derivative used in the method [II] may be only a tetracarboxylic acid diester, but a tetracarboxylic dianhydride may be used in combination. Further, as the diamine used in the method [II], the specific diamine may be used alone, or other diamines may be used in combination. The reaction of method [II] is preferably carried out in an organic solvent in the presence of a suitable dehydration catalyst. Examples of the organic solvent include organic solvents exemplified as those used for the synthesis of polyamic acids. Examples of the dehydration catalyst include 4- (4,6-dimethoxy-1,3,5-triazine-2-yl) -4-methylmorpholinium halide, carbonylimidazole, phosphorus-based condensing agent and the like. The reaction temperature at this time is preferably -20 to 150 ° C, more preferably 0 to 100 ° C. The reaction time is preferably 0.1 to 24 hours, more preferably 0.5 to 12 hours.

The tetracarboxylic dianester dihalide used in the method [III] can be obtained, for example, by reacting the tetracarboxylic dianester obtained as described above with an appropriate chlorinating agent such as thionyl chloride. The tetracarboxylic acid derivative used in the method [III] may be only a tetracarboxylic acid diester, but a tetracarboxylic dianhydride may be used in combination. Further, as the diamine used in the method [III], the specific diamine may be used alone, or other diamines may be used in combination. The reaction of method [III] is preferably carried out in an organic solvent in the presence of a suitable base. Examples of the organic solvent include organic solvents exemplified as those used for the synthesis of polyamic acids. As the base, for example, tertiary amines such as pyridine and triethylamine; alkali metals such as sodium hydride, potassium hydride, sodium hydroxide, potassium hydroxide, sodium and potassium can be preferably used. The reaction temperature at this time is preferably -20 to 150 ° C, more preferably 0 to 100 ° C. The reaction time is preferably 0.1 to 24 hours, more preferably 0.5 to 12 hours.

The polyamic acid ester as the compound (A) may have only an amic acid ester structure, or may be a partial esterified product in which the amic acid structure and the amic acid ester structure coexist. The reaction solution obtained by dissolving the polyamic acid ester may be used as it is for the preparation of the liquid crystal alignment agent, or the polyamic acid ester contained in the reaction solution may be isolated and then used for the preparation of the liquid crystal alignment agent. A well or isolated polyamic acid ester may be purified and then used for preparation of a liquid crystal alignment agent. Isolation and purification of the polyamic acid ester can be carried out according to a known method.
[Polyimide]
The polyimide as the polymer (A) can be obtained, for example, by dehydrating, ring-closing and imidizing the polyamic acid (A) synthesized as described above.

The polyimide may be a completely imidized product in which all of the amic acid structure possessed by the precursor polyamic acid (A) is dehydrated and ring-closed, and only a part of the amic acid structure is dehydrated and ring-closed to form an amic acid. It may be a partially imidized product in which the structure and the imide ring structure coexist. The polyimide used has an imidization ratio of preferably 20% or more, more preferably 30 to 99%, and even more preferably 40 to 99%. This imidization ratio is expressed as a percentage of the ratio of the number of imide ring structures to the total of the number of amic acid structures and the number of imide ring structures of polyimide. Here, a part of the imide ring may be an isoimide ring.

The dehydration ring closure of the polyamic acid (A) is preferably carried out by a method of heating the polyamic acid (A) or by dissolving the polyamic acid (A) in an organic solvent and adding a dehydrating agent and a dehydration ring closure catalyst to this solution. It is carried out by a method of heating according to the above. Of these, the latter method is preferable.

In the method of adding a dehydrating agent and a dehydration ring-closing catalyst to a solution of polyamic acid, an acid anhydride such as acetic anhydride, propionic anhydride, or trifluoroacetic anhydride can be used as the dehydrating agent. The amount of the dehydrating agent used is preferably 0.01 to 20 mol with respect to 1 mol of the amic acid structure of the polyamic acid (A). As the dehydration ring-closing catalyst, for example, tertiary amines such as pyridine, collagen, lutidine, and triethylamine can be used. The amount of the dehydration ring-closing catalyst used is preferably 0.01 to 10 mol with respect to 1 mol of the dehydrating agent used. Examples of the organic solvent used for the dehydration ring closure reaction include organic solvents exemplified as those used for the synthesis of polyamic acid (A). The reaction temperature of the dehydration ring closure reaction is preferably 0 to 180 ° C, more preferably 10 to 150 ° C. The reaction time is preferably 1.0 to 120 hours, more preferably 2.0 to 30 hours.

In this way, a reaction solution containing polyimide is obtained. This reaction solution may be used as it is for the preparation of the liquid crystal alignment agent, or may be used for the preparation of the liquid crystal alignment agent after removing the dehydrating agent and the dehydration ring-closing catalyst from the reaction solution. It may be used for the preparation of the alignment agent, or the isolated polyimide may be purified and then used for the preparation of the liquid crystal alignment agent. These purification operations can be performed according to known methods. In addition, polyimide can also be obtained by imidization of a polyamic acid ester.

The polyamic acid, polyamic acid ester and polyimide as the polymer (A) obtained as described above have a solution viscosity of 10 to 800 mPa · s when this is made into a solution having a concentration of 10% by weight. It is preferable, and it is more preferable that the solution has a viscosity of 15 to 500 mPa · s. The solution viscosity (mPa · s) of the polyamic acid, the polyamic acid ester, and the polyimide is 10% by weight, which is a concentration prepared by using a good solvent (for example, γ-butyrolactone, N-methyl-2-pyrrolidone, etc.) of these polymers. It is a value measured at 25 ° C. using an E-type rotational viscometer with respect to the polymer solution of.

The polystyrene-equivalent weight average molecular weight (Mw) measured by gel permeation chromatography (GPC) of polyamic acid, polyamic acid ester and polyimide is preferably 1,000 to 500,000, more preferably 2,000 to 2,000. It is 300,000. The molecular weight distribution (Mw / Mn) represented by the ratio of Mw to the polystyrene-equivalent number average molecular weight (Mn) measured by GPC is preferably 15 or less, more preferably 10 or less. Within such a molecular weight range, good orientation and stability of the liquid crystal display element can be ensured.
[polyamide]
The polyamide as the polymer (A) can be obtained, for example, by a method of reacting a dicarboxylic acid with a diamine. Here, it is preferable that the dicarboxylic acid is acid chlorided with an appropriate chlorinating agent such as thionyl chloride and then subjected to a reaction with a diamine.

The dicarboxylic acid used for the synthesis of polyamide is not particularly limited, and for example, oxalic acid, malonic acid, dimethylmalonic acid, succinic acid, glutaric acid, adipic acid, 2-methyladipic acid, trimethyladic acid, pimelic acid, 2 , 2-Dimethylglutaric acid, 3,3-diethylsuccinic acid, adipic acid, sebacic acid, suberic acid, fumaric acid, muconic acid and other aliphatic dicarboxylic acids;
A dicarboxylic acid having an alicyclic structure such as cyclobutanedicarboxylic acid, 1-cyclobutenedicarboxylic acid, cyclopentanedicarboxylic acid, cyclohexanedicarboxylic acid;
Phthalic acid, isophthalic acid, terephthalic acid, 5-methylisophthalic acid, 5-tert-butylisophthalic acid, 2,5-dimethylterephthalic acid, naphthalenedicarboxylic acid, 4,4'-biphenyldicarboxylic acid, 4,4'-diphenylmethane Dicarboxylic acid, 4,4'-diphenylpropandicarboxylic acid, 4,4'-diphenyl ether dicarboxylic acid, 4,4'-carbonyl dibenzoic acid, 4-carboxy katsura acid, p-phenylenediacrylic acid, 3,3'- [4,4'-(methylenedi-p-phenylene)] dipropionic acid, 4,4'-[4,4'-(oxydi-p-phenylene)] dibutyric acid, 3,4-diphenyl-1,2- Dicarboxylic acids having an aromatic ring such as cyclobutanedicarboxylic acid; and the like can be mentioned. The dicarboxylic acid may be used alone or in combination of two or more.

The diamine used for synthesizing the polyamide as the polymer (A) contains a specific diamine. In addition, other diamines may be used in combination if necessary. The diamine may be used alone or in combination of two or more.

The ratio of the dicarboxylic acid to the diamine used in the polyamide synthesis reaction is preferably such that the carboxyl group of the dicarboxylic acid is 0.2 to 2 equivalents with respect to 1 equivalent of the amino group of the diamine, and is 0.3 to 0 to. The ratio of 1.2 equivalents is more preferable.

The reaction of a dicarboxylic acid (preferably an acid chloride dicarboxylic acid) with a diamine is carried out in an organic solvent, preferably in the presence of a base. The reaction temperature at this time is preferably 0 ° C. to 200 ° C., more preferably 10 to 100 ° C. The reaction time is preferably 0.5 to 48 hours, more preferably 1 to 36 hours.

As the organic solvent used in the reaction, for example, tetrahydrofuran, dioxane, toluene, chloroform, dimethylformamide, dimethylacetamide, dimethyl sulfoxide, N-methyl-2-pyrrolidone and the like can be preferably used. The amount of the organic solvent used is preferably 400 to 900 parts by weight, more preferably 500 to 700 parts by weight, based on 100 parts by weight of the total amount of the dicarboxylic acid and diamine.

As the base used in the above reaction, for example, tertiary amines such as pyridine, triethylamine, N-ethyl-N and N-diisopropylamine can be preferably used. The amount of the base used is preferably 2 to 4 mol, more preferably 2 to 3 mol, based on 1 mol of the diamine.

As described above, a reaction solution obtained by dissolving polyamide is obtained. This reaction solution may be used as it is for the preparation of the liquid crystal alignment agent, the polyamide contained in the reaction solution may be isolated and then used for the preparation of the liquid crystal alignment agent, or the isolated polyamide may be purified. It may be used for preparation of a liquid crystal aligning agent. Isolation and purification of the polyamide can be performed according to a known method.

The solution viscosity of the polyamide as the polymer (A) preferably has a solution viscosity of 10 to 800 mPa · s when it is made into a solution having a concentration of 10% by weight, and is a solution of 15 to 500 mPa · s. It is more preferable that it has a viscosity. The polystyrene-equivalent weight average molecular weight (Mw) of the polyamide measured by GPC is preferably 1,000 to 500,000, more preferably 5,000 to 300,000.
<Other ingredients>
The liquid crystal alignment agent according to the present invention may contain the polymer (A) and, if necessary, other components. Examples of other components that may be blended in the liquid crystal aligning agent include polymers other than the polymer (A) (hereinafter referred to as “other polymers”), compounds having at least one epoxy group in the molecule, and the like. Examples thereof include functional silane compounds, photopolymerizable compounds, antioxidants, metal chelate compounds, curing accelerators, surfactants, fillers, dispersants, photosensitizers and the like. Examples of the other polymer include a polyamic acid having no cyclobutene ring structure, an imidized polymer of the polyamic acid, a polyamic acid ester having no cyclobutene ring structure, a polyester, a cellulose derivative, a polyacetal, a polystyrene derivative, and a poly. Examples thereof include (styrene-phenylmaleimide) derivatives and poly (meth) acrylates. The blending ratio of these other components can be appropriately selected according to each compound as long as the effects of the present disclosure are not impaired.

The blending ratio of the polymer (A) is preferably 30 parts by weight or more, more preferably 40 parts by weight or more, based on 100 parts by weight of the total of the polymer components contained in the liquid crystal alignment agent. It is more preferably 50 parts by weight or more. This is because if the ratio is less than 30 parts by weight, the film curing is not sufficiently performed and the effect of the present invention tends not to be sufficiently obtained.
<Solvent>
The liquid crystal alignment agent according to the present invention is prepared as a liquid composition in which the polymer (A) and other components to be blended as needed are dispersed or dissolved in an organic solvent.

Examples of the organic solvent used include N-methyl-2-pyrrolidone, γ-butyrolactone, γ-butyrolactam, N, N-dimethylformamide, N, N-dimethylacetamide, 4-hydroxy-4-methyl-2-pentanone, and the like. Ethylene glycol monomethyl ether, butyl lactate, butyl acetate, methyl methoxypropionate, ethyl ethoxypropionate, ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol-n-propyl ether, ethylene glycol-i-propyl ether , Ethylene glycol-n-butyl ether (butyl cellosolve), ethylene glycol dimethyl ether, ethylene glycol ethyl ether acetate, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diisobutyl ketone , Isoamyl propionate, isoamyl isobutyrate, diisopentyl ether, ethylene carbonate, propylene carbonate and the like. These can be used alone or in admixture of two or more.

The solid content concentration in the liquid crystal alignment agent (the ratio of the total weight of the components other than the solvent of the liquid crystal alignment agent to the total weight of the liquid crystal alignment agent) is appropriately selected in consideration of viscosity, volatility, etc., but is preferable. It is in the range of 1 to 10% by weight. That is, the liquid crystal alignment agent is applied to the surface of the substrate as described later, and is preferably heated to form a coating film as a liquid crystal alignment film or a coating film as a liquid crystal alignment film. At this time, if the solid content concentration is less than 1% by weight, the film thickness of the coating film becomes too small, and it becomes difficult to obtain a good liquid crystal alignment film. On the other hand, when the solid content concentration exceeds 10% by weight, the film thickness of the coating film becomes excessive and it is difficult to obtain a good liquid crystal alignment film, and the viscosity of the liquid crystal alignment agent increases and the coatability deteriorates. There is a tendency.

The range of particularly preferable solid content concentration depends on the method used when applying the liquid crystal alignment agent to the substrate. For example, when the spinner method is used, the solid content concentration (the ratio of the total weight of all components other than the solvent in the liquid crystal alignment agent to the total weight of the liquid crystal alignment agent) is in the range of 1.5 to 4.5% by weight. It is particularly preferable to have. In the case of the printing method, it is particularly preferable that the solid content concentration is in the range of 3 to 9% by weight, and the solution viscosity is in the range of 12 to 50 mPa · s. In the case of the inkjet method, it is particularly preferable that the solid content concentration is in the range of 1 to 5% by weight, whereby the solution viscosity is in the range of 3 to 15 mPa · s. The temperature at which the liquid crystal alignment agent is prepared is preferably 10 to 50 ° C, more preferably 20 to 30 ° C.
[Liquid crystal alignment film and liquid crystal display element]
By using the liquid crystal alignment agent described above, the liquid crystal alignment film according to the present invention is produced. Further, the liquid crystal display element according to the present invention includes a liquid crystal alignment film formed by using the liquid crystal alignment agent. The operation mode of the liquid crystal display element according to the present invention is not particularly limited, and for example, TN type, STN type, VA type (including VA-MVA type, VA-PVA type, etc.), IPS type, FFS type, OCB type, etc. Although it can be applied to various operation modes, it is particularly suitable for a liquid crystal display element (liquid crystal element) in PSA mode.

The method for manufacturing the liquid crystal display element can be manufactured by, for example, a process including the following steps.
A step of applying the liquid crystal alignment agent of the present invention on the conductive film of a pair of substrates having a conductive film to form a coating film.
A step of constructing a liquid crystal cell by arranging a pair of substrates on which the coating film is formed so as to face each other with the coating film facing each other via a liquid crystal layer.
A step of irradiating the liquid crystal cell with light while applying a voltage between the conductive films of the pair of substrates.
[First step: formation of coating film]
As the substrate, for example, glass such as float glass and soda glass; a transparent substrate made of plastic such as polyethylene terephthalate, polybutylene terephthalate, polyether sulfone, polycarbonate, and poly (aliphatic olefin) can be used. As the conductive film, it is preferable to use a transparent conductive film, for example, tin oxide NESA film made of (SnO ₂₎ (US PPG registered trademark), indium oxide - consisting of tin oxide _{(In 2} O 3 -SnO ₂₎ An ITO film or the like can be used. The conductive film is preferably a patterned conductive film partitioned into a plurality of regions. With such a conductive film, when a voltage is applied between the conductive films, the direction of the pretilt angle of the liquid crystal molecules can be changed for each region by applying a different voltage in each region, whereby the viewing angle can be changed. It is possible to make the characteristics wider.

The method of applying the liquid crystal aligning agent of the present invention on the surfaces of the pair of substrates on which the transparent conductive film is formed can be preferably performed by an offset printing method, a spin coating method, a roll coater method, or an inkjet printing method. When applying the liquid crystal alignment agent, in order to further improve the adhesiveness between the substrate surface and the transparent conductive film and the coating film, a functional silane compound and functional titanium are applied to the surface of the substrate on which the coating film should be formed. A pretreatment for applying a compound or the like in advance may be performed.

After the liquid crystal alignment agent is applied to the substrate, preheating is preferably performed for the purpose of preventing the applied liquid crystal alignment agent from dripping. The prebake temperature is preferably 30 to 200 ° C, more preferably 40 to 150 ° C, and particularly preferably 40 to 100 ° C. The pre-baking time is preferably 0.25 to 10 minutes, more preferably 0.5 to 5 minutes. Then, a firing (post-baking) step is carried out for the purpose of completely removing the solvent and, if necessary, thermally imidizing the amic acid structure present in the polymer. The post-bake temperature is preferably 80-300 ° C, more preferably 120-250 ° C. The post-baking time is preferably 5 to 200 minutes, more preferably 10 to 100 minutes. The film thickness of the film thus formed is preferably 0.001 to 1 μm, more preferably 0.005 to 0.5 μm.

By removing the organic solvent by heating after applying the liquid crystal alignment agent, a coating film to be an alignment film is formed. At this time, when the polymer contained in the liquid crystal aligning agent of the present invention is a polyamic acid, a polyamic acid ester, or an imidized polymer having an imide ring structure and an amic acid structure, The dehydration ring closure reaction may be allowed to proceed by further heating after the coating film is formed to obtain a more imidized coating film.

The coating film thus formed may be subjected to the following second step as it is, or may be subjected to a second step after rubbing treatment on the coating film surface, if necessary. This rubbing treatment can be performed by rubbing the coated surface with a roll wrapped with a cloth made of fibers such as nylon, rayon, and cotton in a certain direction.
[Second step: Construction of liquid crystal cell]
A liquid crystal cell is manufactured by preparing two substrates on which a liquid crystal alignment film is formed as described above and arranging a liquid crystal layer containing a liquid crystal compound and a photopolymerizable compound between the two substrates arranged to face each other. To do. For example, the following two methods can be mentioned for manufacturing a liquid crystal cell. The first method is a conventionally known method (vacuum injection method). First, two substrates are arranged facing each other through a gap (cell gap) so that the respective liquid crystal alignment films face each other, and the peripheral portions of the two substrates are bonded together using a sealant to form the substrate surface and the sealant. A liquid crystal cell is produced by injecting and filling a liquid crystal compound and a photopolymerizable compound into the cell gap partitioned by the above, and then sealing the injection holes. The second method is a method called the ODF (One Drop Fill) method. For example, an ultraviolet photocurable sealing material is applied to a predetermined place on one of the two substrates on which the liquid crystal alignment film is formed, and a liquid crystal property is further applied to a predetermined number of places on the liquid crystal alignment film surface. After dropping a mixture of the compound and the photopolymerizable compound, the other substrate is bonded so that the liquid crystal alignment films face each other, the liquid crystal compound is spread over the entire surface of the substrate, and then the entire surface of the substrate is irradiated with ultraviolet light. The liquid crystal cell is manufactured by curing the sealant.

Regardless of which method is used, the liquid crystal cell produced as described above is further heated to a temperature at which the used liquid crystal compound takes an isotropic phase, and then slowly cooled to room temperature to allow the liquid crystal to flow during liquid crystal filling. The orientation may be removed.

As the sealing agent, for example, an epoxy resin containing an aluminum oxide sphere as a curing agent and a spacer can be used.

As the liquid crystal compound, a nematic liquid crystal having a negative dielectric anisotropy can be preferably used. For example, a dicyanobenzene liquid crystal, a pyridazine liquid crystal, a shift-based liquid crystal, an azoxy liquid crystal, a biphenyl liquid crystal, a phenylcyclohexane liquid crystal, etc. A terphenyl liquid crystal or the like can be used. Further, as the liquid crystal compound, an alkenyl liquid crystal which is a monofunctional liquid crystal compound having one of an alkenyl group and a fluoroalkenyl group is used in that the response speed of the PSA mode liquid crystal display element can be made faster. It is preferable to use them together. As such an alkenyl liquid crystal, conventionally known ones can be used, and examples thereof include compounds represented by the following formulas (L1-1) to (L1-9).

As the photopolymerizable compound, a compound having a functional group capable of radical polymerization such as an acryloyl group, a methacryloyl group, a vinyl group and the like can be used. From the viewpoint of reactivity, it is preferable to use a polyfunctional compound having an acryloyl group or a methacryloyl group. Further, from the viewpoint of stably maintaining the orientation of the liquid crystal molecules, as the photopolymerizable compound, a compound having at least two or more rings of at least one of a cyclohexane ring and a benzene ring is used as the liquid crystal skeleton. Is preferable. As such a photopolymerizable compound, conventionally known compounds can be used. The blending ratio of the photopolymerizable compound is preferably 0.1 to 0.5% by weight based on the total amount of the liquid crystal compound to be used. The thickness of the liquid crystal layer is preferably 1 to 5 μm.
[Third step: light irradiation step]
After the liquid crystal cell is constructed, the liquid crystal cell is irradiated with light while a voltage is applied between the conductive films of the pair of substrates. The voltage applied here can be, for example, 5 to 50 V DC or AC. Further, as the light to be irradiated, for example, ultraviolet rays containing light having a wavelength of 150 to 800 nm and visible light can be used, but ultraviolet rays containing light having a wavelength of 300 to 400 nm are preferable. As the light source of the irradiation light, for example, a low-pressure mercury lamp, a high-pressure mercury lamp, a deuterium lamp, a metal halide lamp, an argon resonance lamp, a xenon lamp, an excimer laser, or the like can be used. The ultraviolet rays in the above-mentioned preferable wavelength region can be obtained by means of using a light source in combination with, for example, a filter diffraction grating or the like. The irradiation dose of light, preferably less than 1,000 J / ^{m 2} or more 200,000 J / ^{m 2,} more preferably from 1,000~100,000J / ^{m 2.}

Then, a PSA mode liquid crystal display element can be obtained by attaching a polarizing plate to the outer surface of the liquid crystal cell after light irradiation. As the polarizing plate used here, a polarizing plate called an "H film" in which polyvinyl alcohol is stretch-oriented and iodine is absorbed is sandwiched between a cellulose acetate protective film, or a polarizing plate made of the H film itself. Can be mentioned.

The liquid crystal elements of the present disclosure can be effectively applied to various applications, for example, clocks, portable games, word processors, notebook computers, car navigation systems, camcorders, PDAs, digital cameras, mobile phones, smartphones, various monitors. , LCD TVs, information displays and other display devices, dimming films and the like. Further, the liquid crystal element formed by using the liquid crystal alignment agent of the present disclosure can also be applied to a retardation film.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.

The weight average molecular weight, epoxy equivalent, solution viscosity of each polymer solution, and imidization rate of polyimide in each synthesis example were measured by the following methods.
[Weight average molecular weight of polymer]
The weight average molecular weight Mw of the polymer is a polystyrene-equivalent value measured by gel permeation chromatography under the following conditions.

Column: Made by Tosoh Corporation, TSKgelGRCXLII
Solvent: tetrahydrofuran Temperature: 40 ° C
Pressure: 68 kgf / cm ²
[Epoxy equivalent]
The epoxy equivalent is a value measured according to the "hydrochloric acid-methyl ethyl ketone method" of JIS C2105.
[Solution viscosity of polymer solution]
The solution viscosity [mPa · s] of the polymer solution was measured at 25 ° C. using an E-type rotational viscometer for the solution prepared to have a polymer concentration of 10% by weight using a predetermined solvent.
[Imidization rate of polyimide]
The polyimide solution was poured into pure water, the obtained precipitate was sufficiently dried under reduced pressure at room temperature, dissolved in deuterated dimethyl sulfoxide, and ¹ H-NMR was measured at room temperature using tetramethylsilane as a reference substance. From the obtained ¹ H-NMR spectrum, the imidization rate [%] was determined by the formula represented by the following formula (x).

Imidization rate [%] = (1-A ¹ / A ² x α) x 100 ... (x)
(In formula (x), A ¹ is the peak area derived from the proton of the NH group appearing near the chemical shift of 10 ppm, A ² is the peak area derived from other protons, and α is the precursor of the polymer (polyamic acid). ) Is the ratio of the number of other protons to one proton of the NH group.)
<Synthesis of polymer>
[Synthesis Example P1: Polyimide synthesis of polymer (A1)]
220 g (1.0 mol) of 2,3,5-tricarboxycyclopentylacetic acid dianhydride as tetracarboxylic dianhydride, 150 g (0.3 mol) of 3- (2,4-diaminophenoxy) cholesterol as diamine, below. 93 g (0.2 mol) of the compound represented by the formula DA-1-1 and 1- (4-aminophenyl) -2,3-dihydro-1,3,3-trimethyl-1H-inden-5-amine. 133 g (0.5 mol) was dissolved in 2,200 g of N-methyl-2-pyrrolidone (NMP) and reacted at 60 ° C. for 6 hours to obtain a solution containing a polyamic acid. A small amount of the obtained polyamic acid solution was taken and measured, and the solution viscosity was about 1,450 mPa · s.

Next, 2,800 g of NMP was added to the obtained polyamic acid solution, 79 g of pyridine and 100 g of acetic anhydride were added, and a dehydration ring closure reaction was carried out at 110 ° C. for 4 hours. After the dehydration ring closure reaction, the solvent in the system was replaced with a new NMP (the pyridine and acetic anhydride used in the dehydration ring closure reaction were removed from the system by this operation) to form a polyimide polymer (A1). A solution containing (P-1) in an amount of about 15% by weight was obtained. The imidization rate of the obtained polyimide (P-1) was about 51%.

(DA-1-1)
[Synthesis Example P2: Polyamic Acid Synthesis of Polymer (A1)]
200 g (1.0 mol) of 1,2,3,4-cyclobutanetetracarboxylic dianhydride as tetracarboxylic dianhydride, 52 g (0.1 mol) of 3- (3,5-diaminobenzoyloxy) cholesterol as diamine ), 128 g (0.2 mol) of the compound represented by the following formula DA-4-1 and 150 g (0.7 mol) of 2,2'-dimethyl-4,4'-diaminobiphenyl, NMP 3,100 g and γ-. It was dissolved in a mixed solvent consisting of 760 g of butyrolactone and reacted at 40 ° C. for 3 hours to obtain a solution containing 10% by weight of polyamic acid (P-2) as a polymer (A1). The solution viscosity of this polyamic acid solution was 160 mPa · s.

(DA-4-1)
[Synthesis Example P3: Polyimide Synthesis of Other Polymers]
220 g (1.0 mol) of 2,3,5-tricarboxycyclopentylacetic acid dianhydride as tetracarboxylic dianhydride, 74 g (0.15 mol) of 3- (2,4-diaminophenoxy) cholesterol as diamine, 1 -(4-Aminophenyl) -2,3-dihydro-1,3,3-trimethyl-1H-inden-5-amine 40 g (0.15 mol), and 3,5-diaminobenzoic acid 110 g (0.7) Mol) was dissolved in 1,800 g of NMP and reacted at 60 ° C. for 6 hours to obtain a solution containing polyamic acid. A small amount of the obtained polyamic acid solution was taken and measured, and the solution viscosity was about 1,300 mPa · s.

Next, 2,200 g of NMP was added to the obtained polyamic acid solution, 120 g of pyridine and 150 g of acetic anhydride were added, and a dehydration ring closure reaction was carried out at 110 ° C. for 4 hours. After the dehydration ring closure reaction, the solvent in the system was replaced with a new NMP to obtain a solution containing about 15% by weight of polyimide (P-3), which is another polymer. The imidization rate of the obtained polyimide (P-3) was about 67%.
[Synthesis Example P4: Polyamic Acid Synthesis of Other Polymers]
220 g (1.0 mol) of 2,3,5-tricarboxycyclopentylacetic acid dianhydride as tetracarboxylic dianhydride, 4- (2- (4- (4-pentylcyclohexyl) phenoxy) ethoxy) benzene as diamine 79 g (0.2 mol) of 1,3-diamine, 40 g (0.2 mol) of 4,4'-diaminodiphenylmethane, and 91 g (0.6 mol) of 2,5-diaminobenzoic acid were added to 2,700 g of NMP and γ-. It was dissolved in a mixed solvent consisting of 1,200 g of butyrolactone and reacted at 40 ° C. for 3 hours to obtain a solution containing 10% by weight of another polymer, polyamic acid (P-4). The solution viscosity of this polyamic acid solution was 160 mPa · s.
[Synthesis Example S1: Polyorganosiloxane Synthesis of Polymer (A1)]
In a reaction vessel equipped with a stirrer, a thermometer, a dropping funnel and a reflux cooling tube, 197 g of 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane (ECETS) as a hydrolyzable silane compound and the following formula (S-1) 151 g of the compound represented by -1) (ECETS: compound represented by the following formula (S-1-1) = 80:20 (molar ratio)), 500 g of methyl isobutyl ketone as a solvent, and 10.0 g of triethylamine as a catalyst. It was charged and mixed at room temperature. Then, 100 g of deionized water was added dropwise from the dropping funnel over 30 minutes, and then the reaction was carried out at 80 ° C. for 6 hours under reflux with stirring. After completion of the reaction, the organic layer is taken out, washed with a 0.2 wt% ammonium nitrate aqueous solution until the washed water becomes neutral, and then the solvent and water are distilled off under reduced pressure to hydrolyze with an epoxy group. The condensate was obtained as a viscous clear liquid.

^{When 1} H-NMR analysis was performed on this hydrolyzed condensate, a peak attributed to an epoxy group was obtained near chemical shift (δ) = 3.2 ppm according to the theoretical intensity, and a sub-epoxide group was obtained during the reaction. It was confirmed that no reaction had occurred.

The resulting hydrolyzed condensate was then reacted with a carboxylic acid. First, a 200 mL three-necked flask is charged with the hydrolyzed condensate having the epoxy group obtained above, and 30.0 g of methylisobutylketone as a solvent and 75.1 g of 4-octyloxybenzoic acid (OCTBA) as a carboxylic acid (as a raw material). It corresponds to 30 mol% with respect to the total of the hydrolyzable silane compounds used and 38 mol% with respect to the epoxy group having the hydrolyzed condensate.) And 36.1 g of 11- (4-cyclohexylphenoxy) undecanoic acid. (Corresponds to 10 mol% with respect to the total of the hydrolyzable silane compounds used as raw materials.), And 0.10 g of UCAT 18X (trade name, manufactured by San-Apro Co., Ltd., curing accelerator for epoxy compounds) was charged as a catalyst. The reaction was carried out at 100 ° C. for 48 hours with stirring. After completion of the reaction, the organic layer obtained by adding ethyl acetate to the reaction mixture was washed with water three times, dried over magnesium sulfate, and then the solvent was distilled off to obtain polyorganosiloxane (polymer (A1)). 367.4 g of S-1) was obtained. For this polyorganosiloxane (S-1), the polystyrene-equivalent weight average molecular weight Mw measured by gel permeation chromatography (GPC) was 8,000.
[Synthesis Examples S2 to S4, S6: Polyorganosiloxane Synthesis]
By performing the same operation as in Synthesis Example S1 except that the types and amounts of the hydrolyzable silane compound and the carboxylic acid are as shown in Table 1 below, the polymer (A1) polyorganosiloxane (S-2) )-(S-3), (S-6) and other polymers, polyorganosiloxane (S-4), respectively. The yield and Mw of these polyorganosiloxanes are shown in Table 1 below.

The abbreviations for each compound in Table 1 above have the following meanings.
(Hydrolytic silane compound)
ECETS: 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane S-1-1: Compound represented by the following formula (S-1-1)

(S-1-1)
TEOS: Tetraethoxysilane ODES: Octadecyltriethoxysilane S-1-2: Compound represented by the following formula (S-1-2)

(S-1-2)
(carboxylic acid)
OCTBA: 4-octyloxybenzoic acid CPUA: 11- (4-cyclohexylphenoxy) undecanoic acid PCHBA: 4- (4-pentylcyclohexyl) benzoic acid C-1-1: represented by the following formula (C-1-1) Compound

(C-1-1)
C-1-2: Compound represented by the following formula (C-1-2)

(C-1-2)
SACY: Succinic acid = 5ξ-cholestane-3-yl PCCHHUBA: 11- (4- (4'-pentylbi (cyclohexane) -4-yl) phenoxy) undecanoic acid (compound represented by the following formula (p1))
C-1-3: Compound represented by the following formula (C-1-3)

(C-1-3)

The "molar ratio" of the hydrolyzable silane compounds in Table 1 above indicates the ratio of each silane compound used to the total amount of hydrolyzable silane compounds used. The "molar ratio" of carboxylic acids indicates the ratio of each carboxylic acid used to the total amount of hydrolyzable silane compounds used. In Synthesis Examples S1 to S4 and S6, two types of carboxylic acids were used.
[Synthesis Example S5: Polyorganosiloxane Synthesis of Polymer (A1)]
An ethanol solution of oxalic acid was prepared by putting 52.8 g of ethanol into a four-necked reaction flask equipped with a reflux tube and adding 20.0 g of oxalic acid to the ethanol little by little under stirring. Next, this solution is heated to its reflux temperature, and 20.8 g of tetraethoxysilane, 4.2 g of octadecyltriethoxysilane and 54 g of the compound represented by the above formula (S-1-2) are contained in this solution under reflux. The mixture was added dropwise. After completion of the dropping, heating was continued under reflux for 5 hours, then the mixture was cooled, and 75 g of butyl cellosolve was added to prepare a solution containing polyorganosiloxane (S-5) having a _{SiO 2 concentration of 4% by weight.} When this solution was analyzed by gas chromatography, no alkoxysilane monomer was detected.
<Preparation of liquid crystal composition>
[Preparation of liquid crystal composition LC1]
5% by weight of the liquid crystal compound represented by the above formula (L1-1) and the photopolymerizable compound represented by the following formula (L2-1) are added to 10 g of the nematic liquid crystal (MLC-6608 manufactured by Merck). Was added and mixed in an amount of 0.3% by weight to obtain a liquid crystal composition LC1.

[Preparation of liquid crystal composition LC2]
The liquid crystal composition LC2 was prepared in the same manner as the liquid crystal composition LC1 except that the amount of the liquid crystal compound represented by the above formula (L1-1) was changed from 5% by weight to 10% by weight.
<Example 1>
[Preparation of liquid crystal alignment agent]
The solid content weight of each of the solution containing polyimide (P-1) and the solution containing polyamic acid (P-2) becomes polyimide (P-1): polyamic acid (P-2) = 20: 80. As an organic solvent, NMP and butyl cellosolve (BC) were added to the mixed solution to prepare a solution having a solvent composition of NMP: BC = 50: 50 (weight ratio) and a solid content concentration of 6.0% by weight. A liquid crystal alignment agent was prepared by filtering this solution using a filter having a pore size of 1 μm.
[Manufacturing of liquid crystal cells]
Using the liquid crystal alignment agent prepared above, the presence or absence of a transparent electrode pattern and the amount of ultraviolet irradiation (2 levels) were changed to produce a total of 4 liquid crystal cells. In addition, various characteristics of the manufactured liquid crystal cells were evaluated.
[Manufacturing of liquid crystal cells with unpatterned transparent electrodes]
The liquid crystal alignment agent prepared above is applied onto the transparent electrode surface of a glass substrate having a transparent electrode made of an ITO film using a liquid crystal alignment film printing machine (manufactured by Nissha Printing Co., Ltd.), and a hot plate at 80 ° C. is applied. After removing the solvent by heating (pre-baking) for 1 minute on the above, heating (post-baking) for 10 minutes on a hot plate at 150 ° C. was performed to form a coating film having an average film thickness of 600 Å.

This coating film was subjected to a rubbing treatment using a rubbing machine having a roll wrapped with rayon cloth at a roll rotation speed of 400 rpm, a stage moving speed of 3 cm / sec, and a hair-foot pushing length of 0.1 mm. Then, the substrate was ultrasonically cleaned in ultrapure water for 1 minute and then dried in a clean oven at 100 ° C. for 10 minutes to obtain a substrate having a liquid crystal alignment film. This operation was repeated to obtain a pair (two) of substrates having a liquid crystal alignment film. It should be noted that this rubbing process is a weak rubbing process performed for the purpose of controlling the collapse of the liquid crystal and performing the orientation division by a simple method.

Next, for one of the pair of substrates, an epoxy resin adhesive containing aluminum oxide spheres having a diameter of 3.5 μm is applied to the outer edge of the surface having the liquid crystal alignment film, and then the pair of substrates has the liquid crystal alignment film surface. The adhesive was cured by overlapping and crimping so as to face each other. Next, a liquid crystal cell was manufactured by filling the liquid crystal composition LC1 prepared above between the pair of substrates from the liquid crystal injection port and then sealing the liquid crystal injection port with an acrylic photocurable adhesive.

The above operation was repeated to produce two liquid crystal cells having a transparent electrode without a pattern. One of them was used as it was for the evaluation of the voltage retention rate. For the remaining one liquid crystal cell, an AC 10V having a frequency of 60 Hz is applied between the conductive films, and while the liquid crystal is being driven, an ultraviolet irradiation device using a metal halide lamp as a light source is used, and 100,000 J / Ultraviolet rays were irradiated at an irradiation amount of m ^2. It should be noted that this irradiation amount is a value measured using a photometer measured based on a wavelength of 365 nm.
[Evaluation of voltage retention rate]
For each of the liquid crystal cells manufactured above, a voltage of 5 V was applied at 23 ° C. for an application time of 60 microseconds and a span of 167 ms, and then the voltage retention rate (VHR) was measured 167 ms after the application was released. .. The measurement results are shown in Table 2 below. As the measuring device, VHR-1 manufactured by Toyo Technica Co., Ltd. was used.
[Manufacturing of liquid crystal cells having patterned transparent electrodes]
The liquid crystal alignment agent of Example 1 prepared above is patterned in a slit shape as shown in FIG. 1 and liquid crystal is printed on each electrode surface of two glass substrates each having ITO electrodes partitioned into a plurality of regions. It is applied using an alignment film printing machine (manufactured by Nissha Printing Co., Ltd.) and heated (pre-baked) on a hot plate at 80 ° C for 1 minute to remove the solvent, and then heated on a hot plate at 150 ° C for 10 minutes. (Post-baking) was performed to form a coating film having an average film thickness of 600 Å. The coating film was ultrasonically cleaned in ultrapure water for 1 minute and then dried in a clean oven at 100 ° C. for 10 minutes to obtain a substrate having a liquid crystal alignment film. This operation was repeated to obtain a pair (two) of substrates having a liquid crystal alignment film. The electrode pattern used is the same as the electrode pattern in the PSA mode.

Next, an epoxy resin adhesive containing aluminum oxide spheres having a diameter of 5.5 μm was applied to each outer edge of the pair of substrates having the liquid crystal alignment film, and then the liquid crystal alignment film surfaces were overlapped and pressure-bonded so as to face each other. The adhesive was cured. Next, a liquid crystal cell was manufactured by filling the liquid crystal composition LC1 prepared above between the pair of substrates from the liquid crystal injection port and then sealing the liquid crystal injection port with an acrylic photocurable adhesive.

The above operation was repeated to produce a total of two liquid crystal cells having patterned transparent electrodes. One of them was used as it was for the evaluation of AC afterimage characteristics described later. For the remaining one liquid crystal cell, an irradiation amount of ^{100,000 J / m 2} was applied in a state where a voltage was applied between the conductive films by the same method as in the case of manufacturing a liquid crystal display element having a transparent electrode without a pattern. After irradiation with light, it was used for evaluation of AC afterimage characteristics.
[Evaluation of AC afterimage characteristics (evaluation of pre-tilt angle stability)]
For the liquid crystal cells manufactured above, "TJ Scheffer et. Al., J. Appl. Phys. Vol 48, p1783 (1977)", and "F. Nakano, et. Al., JPN. J. Appl. Phys. Vol. 19, p2013 (1980) ”, and the measurement was performed by a rotating crystal method using a He-Ne laser beam. The measurement was performed on the pre-tilt angle (initial pre-tilt angle θini) before applying the voltage to the liquid crystal cell, and the pre-tilt angle (pre-tilt angle θac after driving) after driving at AC9V for 13 hours at room temperature. Further, the pretilt angle change rate β [%] was calculated by the following formula (y). When the pretilt angle change rate β was less than 3%, it was evaluated as “good”, when it was 3% or more and less than 5%, it was evaluated as “good”, and when it was 5% or more, it was evaluated as “bad”. The results are shown in Table 2 below.

Pre-tilt angle change rate β [%] = (θac−θini) / θini × 100… (y)

In addition, "part by weight" in Table 2 above indicates the blending amount of each component with respect to 100 parts by weight of the total amount of the liquid crystal aligning agent.
<Examples 2-9, 11, 12 and Comparative Examples 1, 2>
The liquid crystal alignment agents were prepared in the same manner as in Example 1 except that the type and amount of the polymer used for preparing the liquid crystal alignment agent were changed as shown in Table 2 above. The polyorganosiloxanes (S-1) to (S-4) and (S-6) were dissolved in NMP and then used to prepare a liquid crystal aligning agent. For polyorganosiloxane (S-5), the reaction solution was poured into a large excess of methanol to precipitate the reaction product, the precipitate was washed with methanol and then dried under reduced pressure at 40 ° C. for 15 hours. The powder obtained in the above method was dissolved in MeOH and used for preparation of a liquid crystal aligning agent. Further, using each of these liquid crystal alignment agents, a liquid crystal cell was produced in the same manner as in Example 1, and the produced liquid crystal cell was evaluated. In Examples 6 and 12, the liquid crystal composition used in the production of the liquid crystal cell was changed from LC1 to LC2. The evaluation results are shown in Table 2 above.
[Evaluation of high-speed response]
<Example 6A>
The high-speed response of the liquid crystal molecules was evaluated using the liquid crystal cell having the unpatterned transparent electrode produced in Example 6. After sandwiching the liquid crystal cell manufactured above between two polarizing plates arranged in a cross Nicol state, first, a visible light lamp is irradiated without applying a voltage, and the brightness of the light transmitted through the liquid crystal cell is photographed. It was measured with a multimeter, and this value was defined as a relative transmittance of 0%. Next, the transmittance when AC 5V was applied between the electrodes of the liquid crystal cell for 5 seconds was measured in the same manner as above, and this value was taken as the relative transmittance of 100%. When AC 5V was applied to each liquid crystal cell, the time until the relative transmittance changed from 10% to 90% was measured, and this time was defined as the response speed. When the response speed was less than 5 msec, the high-speed response was judged to be "good", and when the response speed was 5 msec or more, the high-speed response was judged to be "good". As a result, the liquid crystal cell of Example 6 had a "good" high-speed response.
<Example 12A and Comparative Example 1A>
The response speed of the liquid crystal molecules was evaluated by the same operation as in Example 6A above except that the liquid crystal cells used were changed to those of Example 12 and Comparative Example 1. The results are shown in Table 3 below.

<Example 10>
[Preparation of liquid crystal alignment agent]
After dissolving the polyorganosiloxane (S-1) obtained in Synthesis Example S1 in NMP, this polyorganosiloxane-containing solution and the polyimide (P-3) as another polymer obtained in Synthesis Example P3 are added. The contained solutions were mixed so that the weight of each solid content was polyimide (P-3): polyorganosiloxane (S-1) = 90: 5. Next, after adding NMP and BC, N, N, N', N'-tetraglycidyl-4,4'-diaminodiphenylmethane was added in the same amount (weight) as polyorganosiloxane (S-1) to adjust the solvent composition. A solution having NMP: BC = 50: 50 (weight ratio) and a solid content concentration of 6.0% by weight was prepared. A liquid crystal alignment agent was prepared by filtering this solution using a filter having a pore size of 1 μm. Further, a liquid crystal cell was manufactured in the same manner as in Example 1 except that the liquid crystal alignment agent used was changed, and the evaluation was performed. The evaluation results are also shown in Table 2 above.

In Comparative Examples 1 and 2, the decrease in the voltage retention rate and the decrease in the AC afterimage characteristic due to the irradiation with ultraviolet rays were remarkable. On the other hand, in Examples 1 to 12, a high voltage retention rate was maintained even after irradiation with ultraviolet rays, and the AC afterimage characteristics were also good. Among them, in Examples 3, 6, 7, 9, 11 and 12 in which a liquid crystal alignment agent containing at least one of polyamic acid and polyimide as a polymer and polyorganosiloxane (A1) was used, the AC afterimage characteristics were particularly good. there were. From these results, when the alkenyl liquid crystal is used in the PSA mode to speed up the response of the liquid crystal panel, the voltage due to ultraviolet irradiation is obtained by forming the liquid crystal alignment film with the liquid crystal alignment agent containing the polymer (A1). It was found that the decrease in the retention rate can be suppressed and the AC afterimage characteristics can be improved. Further, from the results of Examples 6A and 12A, it was found that a liquid crystal display element having high high-speed response can be obtained.

Further, except that the pattern of the ITO electrode on the glass substrate was changed to the fishbone-shaped electrode pattern as shown in FIGS. 2 and 3, the liquid crystal alignment agents of Examples 1 to 12 were used, and the above Example 1 was used. A liquid crystal cell was manufactured and evaluated in the same manner as in the above. In this case as well, the same effects as in Examples 1 to 12 were exhibited.

1 ... ITO electrode, 2 ... Slit, 3 ... Light-shielding film

Claims (5)

Polysiloxane having at least one partial structure selected from the group represented by the following formula (1) and the following formulas ( 3 ) to ( 8), and
Polyamic acid, polyamic acid ester, polyimide, selected from the group consisting of polyamide, or One lower following formula (1-2) and the following formula (3) at least one partial structure selected from the group represented by - (8) Polymer,
A liquid crystal alignment agent containing at least one polymer selected from the group consisting of.

(In equations (1) and (3) to ( 8 ),
X independently represents a halogen atom, a hydroxyl group, a cyano group, a nitro group, an alkyl group having 1 to 6 carbon atoms, and an alcoholic group having 1 to 6 carbon atoms.
a is an integer from 0 to 4, b is an integer from 0 to 3, c is an integer from 0 to 5, and so on.
R ₁ , R ₂ , R ₄ , R ₅ , R ₆ , R ₇ and R ₈ independently have a hydrogen atom, a halogen atom, a hydroxyl group, an alkyl group having 1 to 20 carbon atoms, and 1 to 20 carbon atoms. the alkoxy group, an aryl group having 6 to 30 carbon atoms, an aryl alkyl group having 7 to 30 carbon atoms, an alkenyl group having 2 to 12 carbon atoms, an alkenyloxy group having 2 to 12 carbon atoms, _{R 1} And R ₂ may be linked to form a 3- to 6-membered cyclic alkane or heterocyclic group, such as an alkyl group, an alcohol group, an aryl group, an arylalkyl group, an alkenyl group, an alkenyloxy group, a cyclic alkyl group, The heterocyclic group may have a substituent and may have a substituent.
R ₃ represents a hydroxyl group, an alkyl group having 1 to 20 carbon atoms substituted or substituted, or any group represented by the following formula (10), and the alkoxy group may have a substituent.

(In formula (10), Y ₂ is a methylene group, -NR, an oxygen atom, and a sulfur atom, R is an independent hydrogen atom and an alkyl group having 1 to 4 carbon atoms, and X and c are the above. Is the same as.)
* Represents a bond. )

(In the formula (1 -2),
X, a, R ₁ , R ₂ , * are the same as above.
d is an integer from 1 to 5
R ₁ and R ₂ may be linked to form a 3- to 6-membered cyclic alkane or heterocyclic group, such as an alkyl group, an alcohol group, an aryl group, an arylalkyl group, an alkenyl group, an alkenyloxy group, or a cyclic alkyl. group, heterocyclic group but it may also have a substituent. ) A polysiloxane having at least one partial structure selected from the groups represented by the formulas (1), (3), (4) and (5), and
Polyamic acid, polyamic acid ester, polyimide, selected from the group consisting of polyamide, and before following formula (1-2), and (3) is selected from the group represented by the formula (4) and (5) Polymers with at least one partial structure,
The liquid crystal alignment agent according to claim 1, which contains at least one polymer selected from the group consisting of. A step of applying the liquid crystal alignment agent according to any one of claims 1 to 2 on the conductive film of a pair of substrates having a conductive film to form a coating film.
A step of constructing a liquid crystal cell by arranging a pair of substrates on which the coating film is formed so as to face each other with the coating film facing each other via a liquid crystal layer.
A method for manufacturing a liquid crystal element, comprising a step of irradiating the liquid crystal cell with light in a state where a voltage is applied between the conductive films of the pair of substrates. A liquid crystal alignment film formed by using the liquid crystal alignment agent according to any one of claims 1 and 2. A liquid crystal element comprising the liquid crystal alignment film according to claim 4.

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