WO2019082975A1

WO2019082975A1 - Liquid crystal alignment agent, liquid crystal alignment film, and liquid crystal display element

Info

Publication number: WO2019082975A1
Application number: PCT/JP2018/039697
Authority: WO
Inventors: 幸司巴; 大輝山極; 早紀相馬; 新平新津
Original assignee: 日産化学株式会社
Priority date: 2017-10-26
Filing date: 2018-10-25
Publication date: 2019-05-02
Also published as: TW201930401A; JPWO2019082975A1; KR102586312B1; KR20200066656A; CN111279255A; CN111279255B; JP7276666B2

Abstract

A liquid crystal alignment agent containing a polyimide that is a reaction product of a diamine component and a tetracarboxylic acid dianhydride derivative component comprising at least one species selected from an aliphatic tetracarboxylic acid dianhydride and an alicyclic tetracarboxylic acid dianhydride, wherein the diamine component contains at least one species selected from diamines represented by formula [A], and the imidization rate of the polyimide is 70% or greater. In the formula: P1 and P2 are phenyl or biphenyl groups, and a hydrogen atom on an aromatic ring thereof may be substituted with a methyl group or a fluorine group; Q is a divalent organic group, and n1 and n2 are integers of 0 to 5, Q being an oxygen atom when n1 and/or n2 is 0.

Description

Liquid crystal aligning agent, liquid crystal aligning film and liquid crystal display device

The present invention relates to a liquid crystal aligning agent, a liquid crystal aligning film, and a liquid crystal display device.

The liquid crystal display element is configured by sandwiching a liquid crystal layer by a pair of transparent substrates provided with electrodes. And in a liquid crystal display element, the organic film which consists of organic materials is used as a liquid crystal aligning film so that a liquid crystal may be in a desired orientation state between board | substrates. That is, the liquid crystal alignment film is a component of the liquid crystal display element, and is formed on the surface of the substrate holding the liquid crystal in contact with the liquid crystal, and plays a role of orienting the liquid crystal in a certain direction between the substrates. Furthermore, the liquid crystal alignment film can control the pretilt angle of the liquid crystal. There is known a method of decreasing the pretilt angle mainly by selecting the structure of polyimide (see Patent Documents 1 and 2).

JP-A-9-188761 JP 10-123 532 A

On the other hand, along with applications such as large-screen high-definition liquid crystal TVs with the advancement of liquid crystal display devices in recent years, car navigation systems, meter panels, monitors for surveillance cameras and medical cameras, for example, Liquid crystal display elements are used in the art, and the rubbing alignment film is required to have a lower pretilt angle than in the prior art because of the demand for viewing angle characteristics.
Also, the viewing angle dependency of color derived from the pretilt angle, so-called color shift, is pointed out as a problem, and in order to solve this problem, an alignment film having a pretilt angle of 1 degree or less is specifically required. .

The inventors conducted various studies to achieve the above object, and found that the liquid crystal aligning agent having the following constitution is most suitable for achieving the above object, and completed the present invention.

Thus, the present invention is based on the above findings and has the following summary.
1. A liquid crystal aligning agent containing a polyimide which is a reaction product of a carboxylic acid dianhydride derivative component comprising at least one selected from aliphatic tetracarboxylic acid dianhydrides and alicyclic tetracarboxylic acid dianhydrides and a diamine component. A liquid crystal aligning agent, wherein the diamine component contains at least one selected from diamines of the following formula [A] (hereinafter, also referred to as specific diamines), and the imidation ratio of the polyimide is 70% or more.

In the formula, P ₁ and P ₂ are a phenyl or biphenyl group, and hydrogen on the aromatic ring may be replaced by a methyl group or a fluorine group. Q is a divalent organic group, and n1 and n2 are integers of 0 to 5. However, when at least one of n1 and n2 is 0, Q is an oxygen atom.
Preferred specific examples of [A] include diamines of the following formulas [A-1] to [A-6].

By using the liquid crystal aligning agent of the present invention, it is possible to obtain a liquid crystal alignment film which satisfies various properties required for the liquid crystal alignment film and which gives a low pretilt angle of 1 degree or less.

<Aliphatic, alicyclic tetracarboxylic acid derivatives>
The polyimide contained in the liquid crystal aligning agent of the present invention is a tetracarboxylic acid dianhydride derivative component comprising at least one selected from aliphatic tetracarboxylic acid dianhydride and alicyclic tetracarboxylic acid dianhydride and a specific diamine Is obtained by imidizing a polyimide precursor obtained from a diamine component containing (hereinafter, also referred to as a specific polymer). Hereinafter, specific examples of the materials to be used and the production method will be described in detail.
Not only tetracarboxylic acid dianhydrides but also tetracarboxylic acid dianhydrides, tetracarboxylic acid dihalide compounds, tetracarboxylic acid dialkyl esters and tetracarboxylic acid dialkyl esters are used as tetracarboxylic acid derivatives used for producing polyimide precursors Ester dihalides are mentioned.
Among the aliphatic and alicyclic tetracarboxylic acid dianhydrides and derivatives thereof, those represented by the following formula (4) are preferable.

In the formula (4), preferable structures of X ₁ include the following formulas (X1-1) to (X1-24).

In formulas (X1-1) to (X1-4), R ₃ to R ₂₃ each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, or an alkenyl group having 2 to 6 carbon atoms, It is an alkynyl group having 2 to 6 carbon atoms, a monovalent organic group having 1 to 6 carbon atoms containing a fluorine atom, or a phenyl group. From the viewpoint of liquid crystal alignment, R ₃ to R ₂₃ are preferably a hydrogen atom, a halogen atom, a methyl group or an ethyl group, and a hydrogen atom or a methyl group is preferable.
Specific examples of the formula (X1-1) include the following formulas (X1-1-1) to (X1-1-6). (X1-1-1) is particularly preferable from the viewpoint of liquid crystal alignment and sensitivity of photoreaction.

<Specific diamine>
The diamine component used for manufacture of the polyimide contained in the liquid crystal aligning agent of this invention contains at least 1 sort (s) chosen from the diamine of following formula [A].

In the formula, P ₁ and P ₂ are a phenyl or biphenyl group, and hydrogen on the aromatic ring may be replaced by a methyl group or a fluorine group. Q is a divalent organic group, and n1 and n2 are integers of 0 to 5. However, when at least one of n1 and n2 is 0, Q is an oxygen atom.

Here, when (n1 + n2) ≧ 1, and either n1 or n2 is 0, Q is preferably an oxygen atom, and in this case, the formula [A] is represented as the following [A ′] .

In the formula, X is a divalent organic group selected from the following structures.

Each * represents a bond to an oxygen atom.
Preferred specific examples of [A] include diamines of the following formulas [A-1] to [A-6]. These may be used alone or in combination of two or more.

The preferred content of the diamine of the above formula [A] is preferably 40% to 80%, more preferably 40% to 70%, still more preferably 40% to 60% of the total diamine components.

<Other diamines>
In addition to the diamine of said Formula [A], the diamine component used for manufacture of the polyimide contained in the liquid crystal aligning agent of this invention can use various diamine according to the characteristic of the liquid crystal aligning agent calculated | required.
Other diamines are represented by the following formula (5).

In the above formula (5), A ₁ and A ₂ each independently represent a hydrogen atom, or an alkyl group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, or an alkynyl group having 2 to 5 carbon atoms is there.
The structure of Y ₁ is not particularly limited. Preferred structures include the following (Y-1) to (Y-177).

In the above formulae, Me represents a methyl group, and R ¹ represents a hydrogen atom or a hydrocarbon group having 1 to 5 carbon atoms.

From the viewpoint of improving the solubility of the polymer, it is preferable to include a structure represented by the following formula (6) in the structure of any Y ₁ .

In the above formula (6), D is a thermally leaving group which is preferably desorbed at 150 to 230 ° C., more preferably 180 to 230 ° C. to replace a hydrogen atom. Specific examples of Y including the structure represented by the above formula (6) include (Y-124) and (Y-158) to (Y-163).

<Polyamic acid>
The polyamic acid which is a polyimide precursor used in the present invention is specified with a tetracarboxylic acid dianhydride derivative component consisting of at least one selected from aliphatic tetracarboxylic acid dianhydride and alicyclic tetracarboxylic acid dianhydride. It is a polyimide precursor obtained from the diamine component containing a diamine, and can be manufactured by the method shown below.
Specifically, an organic tetracarboxylic acid dianhydride derivative component consisting of at least one selected from aliphatic tetracarboxylic acid dianhydrides and alicyclic tetracarboxylic acid dianhydrides and a diamine component containing a specific diamine It can be synthesized by reacting in the presence of a solvent at -20 ° C to 150 ° C, preferably 0 ° C to 50 ° C, for 30 minutes to 24 hours, preferably 1 to 12 hours.

The organic solvent used for the above reaction is preferably N, N-dimethylformamide, N-methyl-2-pyrrolidone or γ-butyrolactone in view of solubility of monomers and polymers, and one or more of these may be mixed You may use. The concentration of the polymer is preferably 1 to 30% by mass, and more preferably 5 to 20% by mass, from the viewpoint that polymer precipitation is unlikely to occur and a high molecular weight polymer is easily obtained.

The polyamic acid obtained as described above can be recovered by precipitating a polymer by pouring the reaction solution into a poor solvent while well stirring it. Further, precipitation is carried out several times, and after washing with a poor solvent, it is possible to obtain a purified polyamic acid powder by normal temperature or heat drying. The poor solvent is not particularly limited, and water, methanol, ethanol, hexane, butyl cellosolve, acetone, toluene and the like can be mentioned.

<Polyamic acid ester>
The polyamic acid ester which is one of the polyimide precursors used for this invention can be manufactured by the method of (I), (II) or (III) shown below.

(I) When Produced from Polyamic Acid A polyamic acid ester can be synthesized by esterifying a polyamic acid obtained from tetracarboxylic acid dianhydride and diamine. Specifically, the polyamic acid and the esterifying agent are reacted in the presence of an organic solvent at -20 ° C to 150 ° C, preferably 0 ° C to 50 ° C, for 30 minutes to 24 hours, preferably 1 to 4 hours. It can be synthesized.

As the esterifying agent, those which can be easily removed by purification are preferable, and N, N-dimethylformamide dimethyl acetal, N, N-dimethylformamide diethyl acetal, N, N-dimethylformamide dipropyl acetal, N, N-dimethylformamide Dineopentyl butyl acetal, N, N-dimethylformamide di-t-butyl acetal, 1-methyl-3-p-tolyltriazene, 1-ethyl-3-p-tolyltriazene, 1-propyl-3-p -Tolyltriazene, 4- (4,6-dimethoxy-1,3,5-triazin-2-yl) -4-methylmorpholinium chloride and the like. The amount of the esterifying agent used is preferably 2 to 6 molar equivalents with respect to 1 mole of the repeating unit of the polyamic acid.

The solvent used for the above reaction is preferably N, N-dimethylformamide, N-methyl-2-pyrrolidone, or γ-butyrolactone in view of the solubility of the polymer, and these may be used alone or in combination of two or more. Good. The concentration of the polymer in the reaction solution is preferably 1 to 30% by mass, and more preferably 5 to 20% by mass, from the viewpoint that precipitation of the polymer hardly occurs and a polymer can be easily obtained.

(II) When manufactured by reaction of tetracarboxylic acid diester dichloride and diamine Polyamic acid ester can be manufactured from tetracarboxylic acid diester dichloride and diamine. Specifically, tetracarboxylic acid diester dichloride and diamine in the presence of a base and an organic solvent at -20 ° C to 150 ° C, preferably 0 ° C to 50 ° C, for 30 minutes to 24 hours, preferably 1 to 4 hours It can be synthesized by reaction.

As the base, pyridine, triethylamine, 4-dimethylaminopyridine and the like can be used, but pyridine is preferable because the reaction proceeds mildly. The amount of the base used is preferably 2 to 4 times the molar amount of the tetracarboxylic acid diester dichloride from the viewpoint of easy removal and high molecular weight.

The solvent used for the above reaction is preferably N-methyl-2-pyrrolidone or γ-butyrolactone in view of the solubility of monomers and polymers, and these may be used alone or in combination of two or more. The concentration of the polymer in the reaction solution is preferably 1 to 30% by mass, and more preferably 5 to 20% by mass, from the viewpoint that precipitation of the polymer hardly occurs and a polymer can be easily obtained. Further, in order to prevent hydrolysis of the tetracarboxylic acid diester dichloride, the solvent used for the synthesis of the polyamic acid ester is preferably dehydrated as much as possible, and it is preferable to prevent the mixing of outside air in a nitrogen atmosphere.

(III) When manufactured by reaction of tetracarboxylic acid diester and diamine Polyamic acid ester can be manufactured by polycondensing tetracarboxylic acid diester and diamine. Specifically, a tetracarboxylic acid diester and a diamine in the presence of a condensing agent, a base and an organic solvent at 0 ° C. to 150 ° C., preferably 0 ° C. to 100 ° C., for 30 minutes to 24 hours, preferably 3 to 15 It can be produced by reacting for time.

Examples of the condensing agent include triphenyl phosphite, dicyclohexyl carbodiimide, 1-ethyl-3- (3-dimethylaminopropyl) carbodiimide hydrochloride, N, N′-carbonyldiimidazole, dimethoxy-1,3,5-triadidi Nylmethylmorpholinium, O- (benzotriazol-1-yl) -N, N, N ', N'-tetramethyluronium tetrafluoroborate, O- (benzotriazol-1-yl) -N, N And N ′, N′-tetramethyluronium hexafluorophosphate, diphenyl (2,3-dihydro-2-thioxo-3-benzoxazolyl) phosphonate and the like can be used. The addition amount of the condensing agent is preferably 2 to 3 moles per mol of the tetracarboxylic acid diester.

As the base, tertiary amines such as pyridine and triethylamine can be used. The amount of the base used is preferably 2 to 4 moles per mole of the diamine component from the viewpoint of easy removal and high molecular weight.

In the above reaction, the reaction proceeds efficiently by adding a Lewis acid as an additive. As the Lewis acid, lithium halides such as lithium chloride and lithium bromide are preferable. The addition amount of the Lewis acid is preferably 0 to 1.0 times the molar amount with respect to the diamine component.

Among the three methods for producing the polyamic acid ester, the method for producing the above (I) or the above (II) is particularly preferable because a high molecular weight polyamic acid ester can be obtained.

The solution of the polyamic acid ester obtained as described above can precipitate the polymer by pouring it into a poor solvent while stirring well. Precipitation is carried out several times, and after washing with a poor solvent, it is possible to obtain a purified polyamic acid ester powder at room temperature or by heating and drying. The poor solvent is not particularly limited, and water, methanol, ethanol, hexane, butyl cellosolve, acetone, toluene and the like can be mentioned.

<Polyimide>
The polyimide used in the present invention can be produced by imidizing the above-mentioned polyamic acid or polyamic acid ester. The imidation ratio of the polyimide used in the present invention is preferably 70 to 99% from the viewpoint of the electrical properties. When producing a polyimide from polyamic acid ester, chemical imidization which adds a basic catalyst to the polyamic acid solution obtained by dissolving the said polyamic acid ester solution or polyamic acid ester resin powder in an organic solvent is simple. Chemical imidization is preferable because the imidization reaction proceeds at a relatively low temperature, and molecular weight reduction of the polymer does not easily occur in the imidization process.

Chemical imidization can be carried out by stirring the polyamic acid or polyamic acid ester to be imidized in an organic solvent in the presence of a basic catalyst and an acid anhydride. As an organic solvent, the solvent used at the time of the polymerization reaction mentioned above can be used. Examples of basic catalysts include pyridine, triethylamine, trimethylamine, tributylamine and trioctylamine. Among them, pyridine is preferable because it has a suitable basicity to allow the reaction to proceed. Further, as the acid anhydride, acetic anhydride, trimellitic anhydride, pyromellitic anhydride and the like can be mentioned, and it is preferable to use acetic anhydride among them because purification after completion of the reaction becomes easy.

The temperature at which the imidization reaction is carried out is, for example, −20 ° C. to 120 ° C., preferably 0 ° C. to 100 ° C., and the reaction time can be 1 to 100 hours. The amount of the basic catalyst is 0.5 to 30 moles, preferably 2 to 20 moles, of the amic acid group, and the amount of the acid anhydride is 1 to 50 moles, preferably 3 to 30 moles of the amic acid group. It is a double. The imidation ratio of the resulting polymer can be controlled by adjusting the amount of catalyst, temperature and reaction time.

Since the added catalyst and the like remain in the solution after the imidization reaction of the polyamic acid ester or the polyamic acid, the obtained imidized polymer is recovered by the means described below, and redissolved in an organic solvent. Preferably, the liquid crystal aligning agent of the present invention is used.

The solution of the polyimide obtained as mentioned above can precipitate a polymer by inject | pouring into a poor solvent, stirring it well. Precipitation is carried out several times, and after washing with a poor solvent, it is possible to obtain a purified polyamic acid ester powder at room temperature or by heating and drying.

The poor solvent is not particularly limited, and methanol, acetone, hexane, butyl cellosolve, heptane, methyl ethyl ketone, methyl isobutyl ketone, ethanol, toluene, benzene and the like can be mentioned.

<Liquid crystal alignment agent>
The liquid crystal aligning agent of the present invention has a form of a solution in which a polymer containing a specific polymer is dissolved in an organic solvent. The molecular weight of the polyimide precursor and the polyimide described in the present invention is preferably 2,000 to 500,000, more preferably 5,000 to 300,000, and still more preferably 10,000 to 100, in weight average molecular weight. , 000. Also, the number average molecular weight is preferably 1,000 to 250,000, more preferably 2,500 to 150,000, and still more preferably 5,000 to 50,000.
The content of the specific polymer in the liquid crystal aligning agent of the present invention is preferably 2 to 10% by mass, and more preferably 3 to 8% by mass, in the liquid crystal aligning agent.
The liquid crystal aligning agent of the present invention may contain, in addition to the specific polymer, a polyamic acid which is a reaction product of an optional tetracarboxylic acid derivative component and an optional diamine component.
When the liquid crystal aligning agent contains the above polyamic acid, the proportion is preferably 10 to 900 parts by mass, and more preferably 25 to 700 parts by mass with respect to 100 parts by mass of polyimide.

Other polymers may be mixed in all the polymer components in the liquid crystal aligning agent of the present invention. Other polymers include cellulose polymers, acrylic polymers, methacrylic polymers, polystyrenes, polyamides, polysiloxanes, and the like. The content of the other polymer other than that is preferably 0.5 to 15 parts by mass, and more preferably 1 to 10 parts by mass with respect to 100 parts by mass in total of the polyimide and the polyamic acid.

The concentration of the polymer of the liquid crystal aligning agent used in the present invention can be appropriately changed by setting the thickness of the coating film to be formed, but from the point of forming a uniform and defect-free coating film, 1 weight % Or more is preferable, and from the viewpoint of storage stability of the solution, 10% by weight or less is preferable.

The solvent in the liquid crystal aligning agent of the present invention is a solvent that dissolves a polyimide precursor and a polyimide (also referred to as a good solvent) or a solvent that improves the coating properties and surface smoothness of the liquid crystal alignment film when the liquid crystal aligning agent is applied. (Also referred to as a poor solvent) is preferably used. Specific examples of other solvents are listed below, but are not limited to these examples.

Specific examples of the good solvent include N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N-butyl-2-pyrrolidone, γ-butyrolactone, γ-valerolactone, 1,3-dimethylimidazolidinone, N, N-dimethylformamide, N, N-dimethylacetamide, dimethylsulfoxide, methyl ethyl ketone, cyclohexanone, cyclopentanone, 3-methoxy-N, N-dimethylpropanamide or 4-hydroxy-4-methyl-2-pentanone and the like. be able to.
Specific examples of the poor solvent include 1-butoxy-2-propanol, 2-butoxy-1-propanol, 2-propoxyethanol, 2- (2-propoxyethoxy) ethanol, 1-propoxy-2-propanol ethanol, isopropyl alcohol 1-butanol, 2-butanol, isobutyl alcohol, tert-butyl alcohol, 1-pentanol, 2-pentanol, 3-pentanol, 2-methyl-1-butanol, isopentyl alcohol, tert-pentyl alcohol, 3 -Methyl-2-butanol, neopentyl alcohol, 1-hexanol, 2-methyl-1-pentanol, 2-methyl-2-pentanol, 2-ethyl-1-butanol, 1-heptanol, 2-heptanol, 3 -Heptanol, 1-octano , 2-octanol, 2-ethyl-1-hexanol, cyclohexanol, 1-methylcyclohexanol, 2-methylcyclohexanol, 3-methylcyclohexanol, 1,2-ethanediol, 1,2-propanediol, 1 , 3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,5-pentanediol, 2-methyl-2,4-pentane Diol, 2-ethyl-1,3-hexanediol, dipropyl ether, dibutyl ether, dihexyl ether, dioxane, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, 1,2-butoxyethane, diethylene glycol dimethy Ether, diethylene glycol methyl ethyl ether, diethylene glycol dibutyl ether, 2-pentanone, 3-pentanone, 2-hexanone, 2-heptanone, 4-heptanone, 3-ethoxybutyl acetate, 1-methylpentyl acetate, 2-ethylbutyl acetate Tart, 2-ethylhexyl acetate, ethylene glycol monoacetate, ethylene glycol diacetate, propylene carbonate, ethylene carbonate, 2- (methoxymethoxy) ethanol, butyl cellosolve, ethylene glycol monoisoamyl ether, ethylene glycol monohexyl ether, 2- (Hexyloxy) ethanol, furfuryl alcohol, diethylene glycol, propylene glycol, 1- (butoxyethoxy) prop Nordol, propylene glycol monomethyl ether acetate, dipropylene glycol, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, tripropylene glycol monomethyl ether, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol mono Butyl ether acetate, ethylene glycol monoacetate, ethylene glycol diacetate, diethylene glycol monoethyl ether acetate, propylene glycol diacetate, diisopentyl ether, diethylene glycol monobutyl ether acetate, 2- (2-ethoxyethoxy) ethyl acetate Tart, diethylene glycol acetate, triethylene glycol Glycol, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, methyl lactate, ethyl lactate, methyl acetate, ethyl acetate, n-butyl acetate, propylene glycol monoethyl ether acetate, methyl pyruvate, ethyl pyruvate, 3-methoxy Methyl propionate, methyl ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, 3-ethoxypropionic acid, 3-methoxypropionic acid, propyl 3-methoxypropionate, butyl 3-methoxypropionate, lactate methyl ester, lactate Ethyl ester, lactic acid n-propyl ester, lactic acid n-butyl ester, lactic acid isoamyl ester, diisobutyl ketone, ethyl carbitol and the like can be mentioned.
Moreover, as a poor solvent, the solvent represented by a following formula is also used preferably.

R _{24 and} R ₂₅ are each independently a linear or branched alkyl group having 1 to 8 carbon atoms. However, R ₂₄ + R ₂₅ is an integer greater than 3.
Further, as the poor solvent, when the solubility of the polyimide precursor and the polyimide contained in the liquid crystal aligning agent in the solvent is high, the solvents represented by the following [D-1] to the formula [D-3] are preferable.

In Formula [D-1], D ¹ represents an alkyl group having 1 to 3 carbon atoms, and in Formula [D-2], D ² represents an alkyl group having 1 to 3 carbon atoms, Formula [D-3] among, ^{D 3} is an alkyl group having 1 to 4 carbon atoms.

Further, the liquid crystal aligning agent of the present invention is at least one kind of substitution selected from the group consisting of a crosslinkable compound having an epoxy group, an isocyanate group, an oxetane group or a cyclocarbonate group, a hydroxyl group, a hydroxyalkyl group and a lower alkoxyalkyl group. A crosslinkable compound having a group or a crosslinkable compound having a polymerizable unsaturated bond may be included.

As such a crosslinking compound, various known compounds can be used depending on the purpose. The following compounds are preferably used.

The content of the crosslinkable compound is preferably 0.1 to 150 parts by mass with respect to 100 parts by mass of all the polymer components. Among these, in order for the crosslinking reaction to proceed and to achieve the desired effect, 0.1 to 100 parts by mass is preferable, and 1 to 50 parts by mass is more preferable.

The liquid crystal aligning agent of this invention can contain the compound which improves the uniformity of the film thickness of a liquid crystal aligning film at the time of apply | coating a liquid crystal aligning agent, and surface smoothness.

As a compound which improves the uniformity of the film thickness of a liquid crystal aligning film, and surface smoothness, a fluorine-type surfactant, a silicone type surfactant, a nonion type surfactant etc. are mentioned.
The amount of surfactant used is preferably 0.01 to 2 parts by mass, more preferably 0.01 to 1 parts by mass, with respect to 100 parts by mass of all polymer components contained in the liquid crystal aligning agent.
Also, it contains a silane coupling agent for the purpose of improving the adhesion between the liquid crystal alignment film and the substrate, and an imidization accelerator for the purpose of efficiently advancing the imidization by heating the polyimide precursor when baking the coating film. You may

<Liquid crystal alignment film, liquid crystal display element>
The liquid crystal aligning film of this invention is a film | membrane obtained by apply | coating said liquid crystal aligning agent to a board | substrate, drying, and baking. The substrate to which the liquid crystal aligning agent of the present invention is applied is not particularly limited as long as it is a highly transparent substrate, and a glass substrate, a silicon nitride substrate, a plastic substrate such as an acrylic substrate or a polycarbonate substrate, or the like can be used. At that time, it is preferable to use a substrate on which an ITO electrode or the like for driving liquid crystal is formed, from the viewpoint of simplification of the process. Further, in the reflection type liquid crystal display element, an opaque material such as a silicon wafer can be used if it is only on one substrate, and in this case, a material that reflects light such as aluminum can also be used for the electrode.

Industrially, the liquid crystal aligning agent is generally applied by screen printing, offset printing, flexographic printing or ink jet method, and as the other coating methods, dip method, roll coater method, slit coater, etc. Methods, spinner methods or spray methods are known.

After the liquid crystal aligning agent is applied onto the substrate, the solvent can be evaporated by using a heating means such as a hot plate, a thermal circulation type oven or an IR (infrared) type oven to form a liquid crystal alignment film. The drying and baking steps after the application of the liquid crystal aligning agent can be performed at any temperature and time. Usually, in order to sufficiently remove the contained solvent, baking is carried out at 50 to 120 ° C. for 1 to 10 minutes, followed by baking at 150 to 300 ° C. for 5 to 120 minutes. The thickness of the liquid crystal alignment film after firing is preferably 5 to 300 nm, and more preferably 10 to 200 nm, because if it is too thin, the reliability of the liquid crystal display element may decrease.

The liquid crystal aligning agent of the present invention can be used as a liquid crystal alignment film without application of alignment treatment in a vertical alignment application or the like after being coated and baked on a substrate and then subjected to alignment treatment by rubbing treatment or photo alignment treatment. A known method or apparatus can be used in alignment treatment such as rubbing treatment or light alignment treatment.
As an example of a method of manufacturing a liquid crystal cell, a liquid crystal display element having a passive matrix structure is described as an example. It may be a liquid crystal display element of an active matrix structure in which a switching element such as a TFT (Thin Film Transistor) is provided in each pixel portion constituting an image display.

Specifically, a transparent glass substrate is prepared, a common electrode is provided on one substrate, and a segment electrode is provided on the other substrate. These electrodes can be, for example, ITO electrodes, and are patterned to provide a desired image display. Then, an insulating film is provided on each substrate so as to cover the common electrode and the segment electrode. The insulating film can be, for example, a film of SiO ₂ -TiO ₂ formed by a sol-gel method.

Next, a liquid crystal alignment film is formed on each substrate, the other substrate is superimposed on one of the substrates so that the liquid crystal alignment film faces each other, and the periphery is bonded with a sealing agent. In order to control the substrate gap, it is usually preferable to mix a spacer in the sealing agent, and to disperse the substrate gap control spacer also in the in-plane portion where the sealing agent is not provided. An opening capable of being filled with liquid crystal from the outside is provided in part of the sealing agent. Next, a liquid crystal material is injected into the space surrounded by the two substrates and the sealing agent through the opening provided in the sealing agent, and then the opening is sealed with an adhesive. For injection, a vacuum injection method may be used, or a method utilizing capillary action in the atmosphere may be used. The liquid crystal material may be either a positive liquid crystal material or a negative liquid crystal material, preferably a negative liquid crystal material. Next, the polarizing plate is installed. Specifically, a pair of polarizing plates is attached to the surface of the two substrates opposite to the liquid crystal layer.

EXAMPLES Hereinafter, the present invention will be specifically described by way of examples and the like, but the present invention is not limited to these examples. In addition, the symbol of a compound and a solvent is as follows.
NMP: N-methyl-2-pyrrolidone GBL: γ-butyrolactone BCS: butyl cellosolve DA-1 to DA-12, CA-1 to CA-6: compounds represented by the following structural formulas.
AD-1: 3-glycidoxypropyltriethoxysilane AD-2: a compound represented by the following structural formula.

<Viscosity>
In the synthesis example, the viscosity of the polymer solution was measured using an E-type viscometer TVE-22H (manufactured by Toki Sangyo Co., Ltd.), a sample volume of 1.1 mL, corn rotor TE-1 (1 ° 34 ', R24), temperature 25 Measured in ° C.

<Measurement of imidation ratio of polyimide>
The imidation ratio of the polyimide in the synthesis example was measured as follows. 30 mg of polyimide powder is placed in an NMR (nuclear magnetic resonance) sample tube (NMR sampling tube standard, φ5 (manufactured by Kusano Scientific Co., Ltd.)), and deuterated dimethyl sulfoxide (DMSO-d6, 0.05 mass% TMS (tetramethylsilane) The mixture (0.53 ml) was added and sonicated to dissolve completely. This solution was subjected to proton NMR measurement at 500 MHz with an NMR measurement device (JNW-ECA 500) (manufactured by Nippon Denshi Datum Co., Ltd.). The imidation ratio is determined using a proton derived from a structure that does not change before and after imidization as a reference proton, and a peak integrated value of this proton and a proton peak derived from the NH group of amic acid appearing around 9.5 ppm to 10.0 ppm It calculated | required by the following formula using integration value.

Imidation ratio (%) = (1−α · x / y) × 100

In the above formula, x is the proton peak integrated value derived from the NH group of the amic acid, y is the peak integrated value of the reference proton, and α is one NH group proton of the amic acid in the case of polyamic acid (imidation ratio is 0%) The ratio of the number of reference protons to.

Synthesis Example 1
225 g (3770 mmol) of DA-1, 167 g (419 mmol) of DA-2 and 117 g (210 mmol) of DA-3 are added to a 7 L separable flask equipped with a stirrer and a nitrogen introduction tube, and 3130 g of NMP added The solution was stirred for dissolution while feeding. While stirring the diamine solution under water cooling, 204 g (910 mmol) of CA-1 was added, and 616 g of NMP was further added, followed by stirring at 40 ° C. for 6 hours under a nitrogen atmosphere. Further, 79.0 g (402 mmol) of CA-2 was added, and 709 g of NMP was further added, followed by stirring for 2 hours at 23 ° C. under a nitrogen atmosphere to obtain a solution of polyamic acid (viscosity: 270 mPa · s) PAA-B1.
400 g of this polyamic acid solution is separated into a 2 L Erlenmeyer flask containing a stirrer, 350 g of NMP, 32.4 g of acetic anhydride and 8.39 g of pyridine are added, and stirred at room temperature for 30 minutes, then at 55 ° C. It was allowed to react for 4 hours. The reaction solution was poured into 2770 g of methanol, and the obtained precipitate was separated by filtration. The precipitate was washed with methanol and then dried under reduced pressure at a temperature of 80 ° C. to obtain a powder of polyimide (imidation ratio: 87%).
Furthermore, 40.0 g of the powder of this polyimide is separated in a 500 mL Erlenmeyer flask containing a stirrer, 293 g of NMP is added, and stirred at 70 ° C. for 24 hours for dissolution to obtain a solution SPI-A1 of polyimide. The

(Composition example 2)
In a 100 mL recovery type flask equipped with a stirrer and a nitrogen inlet tube, 5.62 g (19.2 mmol) of DA-1, 4.18 g (10.5 mmol) of DA-2, and 2.92 g of DA-3 (5. 5 g). 24 mmol) Measured, 54.3 g of NMP was added, and stirred and dissolved while feeding nitrogen. While the diamine solution was stirred under water cooling, 4.50 g (22.7 mmol) of CA-3 was added, 15.5 g of NMP was further added, and the mixture was stirred at 50 ° C. for 1 hour under a nitrogen atmosphere. Furthermore, 2.26 g (11.5 mmol) of CA-2 was added, and 6.80 g of NMP was further added, and the solution was stirred at 23 ° C. for 2 hours under a nitrogen atmosphere to obtain a polyamic acid solution (viscosity: 1300 mPa · s) .
In a 100 mL Erlenmeyer flask containing a stirrer, 27.0 g of this polyamic acid solution is separated, 18.0 g of NMP, 2.96 g of acetic anhydride, and 0.766 g of pyridine are added and stirred at room temperature for 30 minutes. The reaction was carried out at 55 ° C. for 3 hours. The reaction solution was poured into 170 g of methanol, and the obtained precipitate was separated by filtration. The precipitate was washed with methanol and then dried under reduced pressure at a temperature of 80 ° C. to obtain a powder of polyimide (imidation ratio: 86%).
Furthermore, 4.00 g of the powder of this polyimide is taken into a 500 mL Erlenmeyer flask containing a stirring bar, 29.3 g of NMP is added, and stirred at 70 ° C. for 24 hours to dissolve, and then polyimide solution SPI-A2 I got

(Composition example 3)
In a 100 mL recovery type flask equipped with a stirrer and a nitrogen inlet tube, 5.62 g (19.2 mmol) of DA-1, 4.18 g (10.5 mmol) of DA-2, and 2.92 g of DA-3 (5. 5 g). 24 mmol) Measured, 50.9 g of NMP was added, and stirred and dissolved while feeding nitrogen. While stirring this diamine solution under water cooling, 4.50 g (22.7 mmol) of CA-3 was added, and 18.0 g of NMP was further added, and the mixture was stirred at 50 ° C. for 1 hour under a nitrogen atmosphere. Furthermore, 2.63 g (11.7 mmol) of CA-1 was added, and 9.70 g of NMP was further added, and the solution was stirred at 40 ° C. for 2 hours under a nitrogen atmosphere to obtain a polyamic acid solution (viscosity: 1180 mPa · s) .
In a 100 mL Erlenmeyer flask containing a stirrer, 25.0 g of this polyamic acid solution is separated, 8.33 g of NMP, 2.96 g of acetic anhydride, and 0.766 g of pyridine are added and stirred at room temperature for 30 minutes. The reaction was carried out at 55 ° C. for 3 hours. The reaction solution was poured into 170 g of methanol, and the obtained precipitate was separated by filtration. The precipitate was washed with methanol and then dried under reduced pressure at a temperature of 80 ° C. to obtain a powder of polyimide (imidation ratio: 86%).
Furthermore, 4.00 g of the powder of this polyimide is taken into a 500 mL Erlenmeyer flask containing a stirring bar, 29.3 g of NMP is added, and stirred at 70 ° C. for 24 hours to dissolve, and polyimide solution SPI-A3 I got

(Composition example 4)
In a 100 mL recovery type flask equipped with a stirrer and a nitrogen inlet tube, 4.82 g (16.4 mmol) of DA-1, 3.58 g (8.98 mmol) of DA-2, 2.50 g of DA-3 (4. 49 mmol) Measured, 53.3 g of NMP was added, and stirred and dissolved while feeding nitrogen. While the diamine solution was stirred under water cooling, 4.96 g (22.1 mmol) of CA-1 was added, 19.3 g of NMP was further added, and the mixture was stirred at 50 ° C. for 1 hour under a nitrogen atmosphere. Furthermore, 1.50 g (5.99 mmol) of CA-4 was added, and 6.35 g of NMP was further added, and the solution was stirred at 40 ° C. for 15 hours under a nitrogen atmosphere to obtain a solution of polyamic acid (viscosity: 427 mPa · s) .
In a 100 mL Erlenmeyer flask containing a stirrer, 30.0 g of this polyamic acid solution is separated, 15.0 g of NMP, 2.85 g of acetic anhydride, and 0.737 g of pyridine are added and stirred at room temperature for 30 minutes. The reaction was carried out at 55 ° C. for 3 hours. The reaction solution was poured into 170 g of methanol, and the obtained precipitate was separated by filtration. The precipitate was washed with methanol and then dried under reduced pressure at a temperature of 80 ° C. to obtain a powder of polyimide (imidation ratio: 84%).
Furthermore, 4.00 g of powder of this polyimide is taken into a 500 mL Erlenmeyer flask containing a stirrer, 29.3 g of NMP is added, and stirred at 70 ° C. for 24 hours to dissolve, and then polyimide solution SPI-A4 I got

(Composition example 5)
In a 100 mL recovery type flask equipped with a stirrer and a nitrogen inlet tube, 2.89 g (9.88 mmol) of DA-1, 3.94 g (9.89 mmol) of DA-2, and 2.75 g of DA-3 (4. 94 mmol) and 2.01 g (8.22 mmol) of DA-4 were weighed out, 49.5 g of NMP was added, and the solution was stirred and dissolved while feeding nitrogen. While stirring the diamine solution under water cooling, 4.25 g (21.4 mmol) of CA-3 was added, and 14.7 g of NMP was further added, followed by stirring at 50 ° C. for 1 hour under a nitrogen atmosphere. Furthermore, 2.04 g (10.4 mmol) of CA-2 was added, and 6.96 g of NMP was further added, and the solution was stirred at 23 ° C. for 2 hours under a nitrogen atmosphere to obtain a polyamic acid solution (viscosity: 1170 mPa · s) .
In a 100 mL Erlenmeyer flask containing a stirrer, 25.0 g of this polyamic acid solution is separated, 16.6 g of NMP, 2.81 g of acetic anhydride, and 0.728 g of pyridine are added and stirred at room temperature for 30 minutes. The reaction was carried out at 55 ° C. for 3 hours. The reaction solution was poured into 160 g of methanol, and the obtained precipitate was separated by filtration. The precipitate was washed with methanol and dried under reduced pressure at a temperature of 80 ° C. to obtain a powder of polyimide (imidation ratio: 82%).
Furthermore, 4.00 g of powder of this polyimide is taken into a 500 mL Erlenmeyer flask containing a stirrer, 29.3 g of NMP is added, and stirred at 70 ° C. for 24 hours to dissolve, and polyimide solution SPI-A5 I got

Synthesis Example 6
In a 300 mL eggplant flask equipped with a stirrer and a nitrogen inlet tube, 6.33 g (15.8 mmol) of DA-2, 4.42 g (7.94 mmol) of DA-3, and 8.52 g of DA-8 (29. 1 mmol) Measured, 150 g of NMP was added, and stirred and dissolved while feeding nitrogen. While stirring this diamine solution under water cooling, 7.72 g (34.4 mmol) of CA-1 was added, 10.0 g of NMP was further added, and the mixture was stirred at 40 ° C. for 6 hours under a nitrogen atmosphere. Furthermore, 3.38 g (17.2 mmol) of CA-2 was added, and 10.0 g of NMP was further added, and the solution was stirred at 23 ° C. for 2 hours under a nitrogen atmosphere to obtain a polyamic acid solution (viscosity: 190 mPa · s) .
150 g of this polyamic acid solution is separated into a 500 mL Erlenmeyer flask containing a stirrer, 130 g of NMP, 12.1 g of acetic anhydride, 3.13 g of pyridine and stirred at room temperature for 30 minutes, then at 55 ° C. It was allowed to react for 4 hours. The reaction solution was poured into 1040 g of methanol, and the obtained precipitate was separated by filtration. The precipitate was washed with methanol and then dried under reduced pressure at a temperature of 80 ° C. to obtain a powder of polyimide (imidation ratio: 81%).
Furthermore, 4.00 g of powder of this polyimide is taken into a 500 mL Erlenmeyer flask containing a stirrer, 29.3 g of NMP is added, and stirred at 70 ° C. for 24 hours to dissolve, and polyimide solution SPI-A6 I got

Synthesis Example 7
1.12 g (4.49 mmol) of DA-5, 1.49 g (7.47 mmol) of DA-6, and 0.590 g of DA-7 in a 100 mL recovery type flask equipped with a stirrer and a nitrogen introduction tube. 97 mmol) Measured, 15.5 g of NMP and 15.5 g of GBL were added and dissolved by stirring while feeding nitrogen. While stirring this diamine solution under water cooling, 1.15 g (5.86 mmol) of CA-2 was added, and 5.00 g of NMP and 5.00 g of GBL were further added, followed by stirring at 25 ° C. for 1 hour under a nitrogen atmosphere. . Further, 2.60 g (8.83 mmol) of CA-5 is added, 5.00 g of NMP and 5.00 g of GBL are further added, and the solution is stirred at 50 ° C. for 12 hours under a nitrogen atmosphere to obtain a polyamic acid solution (viscosity: 200 mPa · s) PAA-A1 was obtained.

Synthesis Example 8
After 30.0 g of the solution PAA-B1 of the polyamic acid obtained in Synthesis Example 1 was separated, 26.2 g of NMP, 2.44 g of acetic anhydride, and 0.630 g of pyridine were added and stirred at room temperature for 30 minutes. The reaction was allowed to proceed at 40 ° C. for 30 minutes. The reaction solution was poured into 150 g of methanol, and the resulting precipitate was filtered off. The precipitate was washed with methanol and then dried under reduced pressure at a temperature of 80 ° C. to obtain a powder of polyimide (imidation ratio: 40%).
Furthermore, 2.00 g of the powder of this polyimide is taken into a 500 mL Erlenmeyer flask containing a stirrer, 14.6 g of NMP is added, and the solution is stirred for 24 hours at 70 ° C. to dissolve, and a solution SPI-B1 of polyimide I got

Synthesis Example 9
In a 200 mL eggplant flask equipped with a stirrer and a nitrogen inlet tube, 8.04 g (27.5 mmol) of DA-1, 5.98 g (15.0 mmol) of DA-2, and 4.17 g (7. 7) of DA-3. 50 mmol) Measured, 111 g of NMP was added, and stirred and dissolved while feeding nitrogen. While stirring this diamine solution under water cooling, 7.29 g (32.5 mmol) of CA-1 was added, 22.0 g of NMP was further added, and the mixture was stirred at 40 ° C. for 6 hours under a nitrogen atmosphere. Furthermore, 3.16 g (14.5 mmol) of CA-6 was added, and 28.5 g of NMP was further added, and the solution was stirred at 50 ° C. for 12 hours under a nitrogen atmosphere to obtain a polyamic acid solution (viscosity: 280 mPa · s) .
In a 300 mL Erlenmeyer flask containing a stirrer, 100 g of this polyamic acid solution is added, 87.5 g of NMP, 8.02 g of acetic anhydride, and 2.07 g of pyridine are added, and stirred at room temperature for 30 minutes. The reaction was allowed to proceed for 4 hours. The reaction solution was poured into 700 g of methanol, and the resulting precipitate was filtered off. The precipitate was washed with methanol and dried under reduced pressure at a temperature of 80 ° C. to obtain a powder of polyimide (imidation ratio: 82%).
Furthermore, 10.0 g of the powder of this polyimide is separated into a 500 mL Erlenmeyer flask containing a stirring bar, 73.3 g of NMP is added, and stirred at 70 ° C. for 24 hours to dissolve, and polyimide solution SPI-B2 I got

Synthesis Example 10
In a 100 mL recovery type flask equipped with a stirrer and a nitrogen inlet tube, 5.62 g (19.3 mmol) of DA-8, 4.18 g (10.5 mmol) of DA-2, and 2.92 g of DA-3 (5. 5 g). 25 mmol) Measured, 54.3 g of NMP was added, and stirred and dissolved while feeding nitrogen. While stirring this diamine solution under water cooling, 4.51 g (22.8 mmol) of CA-3 was added, and 15.5 g of NMP was further added, followed by stirring at 50 ° C. for 1 hour under a nitrogen atmosphere. Furthermore, 2.29 g (11.7 mmol) of CA-2 was added, and 8.30 g of NMP was further added, and the solution was stirred at 23 ° C. for 2 hours under a nitrogen atmosphere to obtain a polyamic acid solution (viscosity: 1210 mPa · s) .
Chemical imidization is carried out using the obtained polyamic acid in the same manner as in Synthesis Example 2 to obtain a powder of polyimide (imidation ratio: 83%), and it is further dissolved in NMP to obtain a solution SPI-A7 of polyimide. The

Synthesis Example 11
In a 100 mL recovery type flask equipped with a stirrer and a nitrogen inlet tube, 5.62 g (19.3 mmol) of DA-9, 4.18 g (10.5 mmol) of DA-2, and 2.92 g of DA-3 (5. 5 g). 25 mmol) Measured, 54.3 g of NMP was added, and stirred and dissolved while feeding nitrogen. While stirring this diamine solution under water cooling, 4.51 g (22.8 mmol) of CA-3 was added, and 15.5 g of NMP was further added, followed by stirring at 50 ° C. for 1 hour under a nitrogen atmosphere. Furthermore, 2.33 g (11.9 mmol) of CA-2 was added, and 8.50 g of NMP was further added, and the solution was stirred at 23 ° C. for 2 hours under a nitrogen atmosphere to obtain a polyamic acid solution (viscosity: 900 mPa · s) .
Chemical imidization is carried out using the obtained polyamic acid in the same manner as in Synthesis Example 2 to obtain a powder of a polyimide (imidation ratio: 80%) and further dissolved in NMP to obtain a solution SPI-A8 of the polyimide. The

Synthesis Example 12
In a 100 mL recovery type flask equipped with a stirrer and a nitrogen inlet tube, 7.09 g (19.3 mmol) of DA-10, 4.18 g (10.5 mmol) of DA-2, and 2.92 g of DA-3 (5. 25 mmol) Measured, 60.5 g of NMP was added, and stirred and dissolved while feeding nitrogen. While stirring this diamine solution under water cooling, 4.51 g (22.8 mmol) of CA-3 was added, and further 15.2 g of NMP was added, and the mixture was stirred at 50 ° C. for 1 hour under a nitrogen atmosphere. Furthermore, 2.25 g (11.5 mmol) of CA-2 was added, and 8.10 g of NMP was further added, and the solution was stirred at 23 ° C. for 2 hours under a nitrogen atmosphere to obtain a polyamic acid solution (viscosity: 1250 mPa · s) .
Chemical imidization is carried out using the obtained polyamic acid in the same manner as in Synthesis Example 2 to obtain a powder of polyimide (imidation ratio: 75%), and it is further dissolved in NMP to obtain a solution SPI-A9 of polyimide. The

Synthesis Example 13
In a 100 mL recovery type flask equipped with a stirrer and a nitrogen inlet tube, 7.40 g (19.3 mmol) of DA-11, 4.18 g (10.5 mmol) of DA-2, and 2.92 g of DA-3 (5. 25 mmol) Measured, 61.8 g of NMP was added, and stirred and dissolved while feeding nitrogen. While stirring this diamine solution under water cooling, 4.51 g (22.8 mmol) of CA-3 was added, and further 15.2 g of NMP was added, and the mixture was stirred at 50 ° C. for 1 hour under a nitrogen atmosphere. Furthermore, 2.30 g (11.7 mmol) of CA-2 was added, and 8.20 g of NMP was further added, and the solution was stirred at 23 ° C. for 2 hours under a nitrogen atmosphere to obtain a polyamic acid solution (viscosity: 980 mPa · s) .
Chemical imidization is carried out using the obtained polyamic acid in the same manner as in Synthesis Example 2 to obtain a powder of a polyimide (imidation ratio: 81%) and further dissolved in NMP to obtain a solution SPI-A10 of the polyimide. The

Synthesis Example 14
9.17 g (19.3 mmol) of DA-12, 4.18 g (10.5 mmol) of DA-2, and 2.92 g of DA-3 in a 100 mL eggplant flask equipped with a stirrer and a nitrogen inlet tube. 25 mmol) Measured, 69.4 g of NMP was added, and stirred and dissolved while feeding nitrogen. While stirring this diamine solution under water cooling, 4.51 g (22.8 mmol) of CA-3 was added, and 14.8 g of NMP was further added, followed by stirring at 50 ° C. for 1 hour under a nitrogen atmosphere. Further, 2.34 g (12.0 mmol) of CA-2 was added, and 8.30 g of NMP was further added, and the solution was stirred at 23 ° C. for 2 hours under a nitrogen atmosphere to obtain a polyamic acid solution (viscosity: 1030 mPa · s) .
Chemical imidization is carried out using the obtained polyamic acid in the same manner as in Synthesis Example 2 to obtain a powder of polyimide (imidation ratio: 83%), and further, it is dissolved in NMP to obtain a solution SPI-A11 of polyimide. The

Synthesis Example 15
In a 100 mL Erlenmeyer flask containing a stirrer, 30.0 g of the solution of polyamic acid obtained in Synthesis Example 2 is separated, 0.470 g of di-tert-butyl dicarbonate is added, and then reacted at 40 ° C. for 12 hours. The Furthermore, 20.0 g of NMP, 3.85 g of acetic anhydride, and 1.28 g of pyridine were added, and the mixture was stirred at room temperature for 30 minutes and then reacted at 60 ° C. for 4 hours. The reaction solution was poured into 220 g of methanol, and the resulting precipitate was filtered off. The precipitate was washed with methanol and then dried under reduced pressure at a temperature of 80 ° C. to obtain a powder of polyimide (imidation ratio: 90%).
Furthermore, 3.50 g of the powder of this polyimide is separated into a 500 mL Erlenmeyer flask containing a stirrer, 25.6 g of NMP is added, and stirred at 70 ° C. for 24 hours to dissolve, and polyimide solution SPI-A12 I got

(Examples 1 to 15) and (Comparative Examples 1 to 3)
NMP was added to a solution obtained by mixing the solution of polyamic acid obtained in Synthesis Example 1 to 15 and the solution of polyimide in the ratio of polymer 1 and polymer 2 as shown in the following table. GBL, BCS, NMP solution containing 1% by weight of AD-1, and NMP solution containing 10% by weight of AD-2 are added while stirring to obtain the composition shown in the table below, and further stirred at room temperature for 2 hours Thus, liquid crystal aligning agents of Examples 1 to 15 and Comparative Examples 1 to 3 were obtained.

Hereinafter, a method of manufacturing the liquid crystal cell 1 for evaluating the pretilt angle and the voltage holding ratio, and the liquid crystal cell 2 for evaluating the liquid crystal alignment property will be described.

[Production of Liquid Crystal Cell 1]
First, a substrate with an electrode was prepared. The substrate is a glass substrate with a size of 30 mm × 40 mm and a thickness of 1.1 mm. An ITO electrode having a film thickness of 35 nm is formed on the substrate, and the electrode has a stripe pattern of 40 mm long and 10 mm wide.
Next, the liquid crystal aligning agent was filtered through a filter with a pore diameter of 1.0 μm, and then applied to the prepared electrode-equipped substrate by spin coating. After drying on a hot plate at 80 ° C. for 2 minutes, baking was carried out in an IR oven at 230 ° C. for 20 minutes to form a coating film with a film thickness of 100 nm to obtain a substrate with a liquid crystal alignment film. This liquid crystal alignment film is rubbed with a rayon cloth (roller diameter: 120 mm, roller rotational speed: 1000 rpm, moving speed: 20 mm / sec, indentation length: 0.4 mm), and then ultrasonic irradiation is performed for 1 minute in pure water. The resultant was washed, air droplets were removed by air blow, and dried at 80 ° C. for 10 minutes to obtain a substrate with a liquid crystal alignment film. Two substrates with this liquid crystal alignment film are prepared, and a spacer of 4 μm is sprayed on the surface of one liquid crystal alignment film, and then a sealing agent is printed thereon, and the rubbing direction of the other substrate is reverse. And, after bonding so that the film surfaces face each other, the sealing agent was cured to produce an empty cell. A liquid crystal MLC-3019 (manufactured by Merck & Co., Ltd.) was injected into the empty cell by a reduced pressure injection method, and the injection port was sealed to obtain a liquid crystal cell. Thereafter, the obtained liquid crystal cell was heated at 120 ° C. for 1 hour, allowed to stand at 23 ° C. overnight, and then used for each evaluation.

[Fabrication of liquid crystal cell 2]
A glass substrate with a size of 30 mm × 35 mm and a thickness of 0.7 mm was prepared. On the substrate, an IZO electrode having a solid pattern is formed, which constitutes a counter electrode as a first layer. A SiN (silicon nitride) film formed by the CVD method is formed as a second layer on the first counter electrode. The film thickness of the second SiN film is 500 nm and functions as an interlayer insulating film. A comb-like pixel electrode formed by patterning an IZO film as a third layer is disposed on the second layer SiN film, and two pixels of a first pixel and a second pixel are formed. ing. The size of each pixel is about 10 mm in height and about 5 mm in width. At this time, the first opposing electrode and the third pixel electrode are electrically insulated by the action of the second SiN film.

The pixel electrode of the third layer has a comb-like shape configured by arranging a plurality of “く” shaped electrode elements whose central portion is bent as shown in FIG. 3 described in JP-A-2014-77845. It has the shape of The width in the short direction of each electrode element is 3 μm, and the distance between the electrode elements is 6 μm. Since the pixel electrode forming each pixel is configured by arranging a plurality of bent "字" shaped electrode elements in the central portion, the shape of each pixel is not rectangular, and the center is the same as the electrode elements. It has a shape resembling a bold "字" that bends in parts. And each pixel is divided up and down bordering on the central bending part, and has the 1st field of the upper part of a bending part, and the 2nd field of the lower side.

When the first region and the second region of each pixel are compared, the forming directions of the electrode elements of the pixel electrodes constituting them are different. That is, on the basis of the rubbing direction of the liquid crystal alignment film described later, the electrode element of the pixel electrode is formed at an angle of + 10 ° (clockwise) in the first region of the pixel, and the pixel in the second region of the pixel The electrode elements of the electrodes are formed at an angle of -10 ° (clockwise). In addition, in the first area and the second area of each pixel, the directions of rotational movement (in-plane switching) in the substrate plane of the liquid crystal induced by voltage application between the pixel electrode and the counter electrode are mutually different. It is configured to be in the opposite direction.

Next, the liquid crystal aligning agent is filtered with a filter having a pore diameter of 1.0 μm, and then an ITO film is formed on the back surface as the electrode-attached substrate and the opposite substrate, and a glass substrate having columnar spacers of 4 μm in height Each was spin-coated. Next, after drying for 2 minutes on a hot plate at 80 ° C., baking was performed at 230 ° C. for 20 minutes to obtain a polyimide film with a film thickness of 60 nm on each substrate. This liquid crystal alignment film is rubbed with a rayon cloth (roller diameter: 120 mm, roller rotation speed: 500 rpm, moving speed: 30 mm / sec, indentation length: 0.3 mm), and then ultrasonic irradiation is performed for 1 minute in pure water. The resultant was washed, air droplets were removed by air blow, and dried at 80 ° C. for 10 minutes to obtain a substrate with a liquid crystal alignment film.
Using the two types of substrates with the liquid crystal alignment film, they were combined so that their rubbing directions would be antiparallel, and the periphery was sealed leaving a liquid crystal injection port to produce an empty cell with a cell gap of 3.8 μm. . Liquid crystal MLC-3019 (manufactured by Merck & Co., Ltd.) was vacuum injected into this empty cell at normal temperature, and then the inlet was sealed to obtain a liquid crystal cell of anti-parallel alignment. The obtained liquid crystal cell constituted an FFS mode liquid crystal display element. Thereafter, the liquid crystal cell was heated at 120 ° C. for 1 hour, allowed to stand at 23 ° C. overnight, and then used for each evaluation described below.

<Pretilt angle>
The pretilt angle in the liquid crystal cell 1 was evaluated using AxoScan Muller matrix polarimeter manufactured by Optometrics.

<Voltage holding ratio>
A voltage of 1 V was applied for 60 μsec at a temperature of 60 ° C. to the liquid crystal cell 1 and the voltage after 50 msec was measured to evaluate how much the voltage could be maintained as a voltage retention rate.

<Evaluation of liquid crystal alignment>
Using the liquid crystal cell 2, an alternating voltage of 9 VPP was applied at a frequency of 30 Hz for 170 hours in a constant temperature environment of 60 ° C. Thereafter, the pixel electrode and the counter electrode of the liquid crystal cell were short-circuited, and left at room temperature for a day.

After standing overnight at 23 ° C., this liquid crystal cell is placed between two polarizing plates disposed so that the polarization axes are orthogonal to each other, and the backlight is turned on with no voltage applied, and the brightness of the transmitted light The arrangement angle of the liquid crystal cell was adjusted so as to minimize. Then, the rotation angle when the liquid crystal cell is rotated from the angle at which the second region of the first pixel is the darkest to the angle at which the first region is the dark is calculated as the angle Δθ1. The angle Δθ2 was calculated by comparing with the first region. The average value of these Δθ1 and Δθ2 was defined as the angle Δθ of the liquid crystal cell, and the smaller this value, the better the liquid crystal alignment was defined and evaluated.

The liquid crystal display devices using the liquid crystal aligning agents of Examples 1 to 15 and Comparative Examples 1 to 3 above show the results of the pretilt angle, the voltage holding ratio, and the liquid crystal cell angle Δθ performed as described above. .

It can be seen that the liquid crystal display device using the liquid crystal aligning agent of the embodiment of the present invention has a low pretilt angle, a high voltage holding ratio, and good liquid crystal alignment.

Claims

A liquid crystal aligning agent containing a polyimide which is a reaction product of a tetracarboxylic acid dianhydride derivative component composed of at least one selected from aliphatic tetracarboxylic acid dianhydride and alicyclic tetracarboxylic acid dianhydride and a diamine component It is a liquid crystal aligning agent whose diamine component contains at least 1 sort (s) chosen from diamine of following formula [A], and the imidation ratio of a polyimide is 70% or more.

In the formula, P 1 and P 2 are a phenyl or biphenyl group, and hydrogen on the aromatic ring may be replaced by a methyl group or a fluorine group. Q is a divalent organic group, and n1 and n2 are integers of 0 to 5. However, when at least one of n1 and n2 is 0, Q is an oxygen atom.
The liquid crystal aligning agent according to claim 1, wherein the diamine of the formula [A] is at least one selected from the following formulas [A-1] to [A-6].
The liquid crystal aligning agent according to claim 1 or 2, wherein the diamine of the formula [A] is 40% to 80% of the total diamine component.
The liquid crystal aligning agent of any one of Claims 1-3 in which the said diamine component contains the diamine which has a structure of following formula (6) in the structure further.

In the above formula (6), D is a thermally releasable group capable of desorbing at 150 to 230 ° C. and replacing a hydrogen atom.
The liquid crystal aligning agent of Claim 4 whose diamine which has a structure of the said Formula (6) is at least 1 sort (s) chosen from the following diamine.

In the formula, n is an integer of 1 to 12.
The liquid crystal aligning agent of any one of Claim 1 to 5 whose aliphatic tetracarboxylic acid dianhydride and alicyclic tetracarboxylic acid dianhydride are represented by following formula (4).

In the formula, X 1 is a structure selected from the following structures.
The liquid crystal aligning agent according to any one of claims 1 to 6, further comprising a polyamic acid which is a reaction product of a tetracarboxylic acid dianhydride derivative and a diamine.
A liquid crystal alignment film obtained from the liquid crystal alignment agent according to any one of claims 1 to 7.
The liquid crystal display element which comprises the liquid crystal aligning film of Claim 8.