WO2019082913A1 - Liquid crystal alignment agent, liquid crystal alignment film, and liquid crystal display element - Google Patents

Abstract

This liquid crystal alignment agent contains an organic solvent and at least one polymer selected from polyimide precursors which are a reaction product of a tetracarboxylic acid derivative and a diamine, and polyimides which are imidization products of the polyimide precursors, wherein the organic solvent contains component A which is at least one selected from γ-butyrolactone and γ-valerolactone, and component B which is at least one selected from dipropylene glycol dimethyl ether and diacetone alcohol, the contained amounts of component A and component B are both not more than 25 wt%, and the difference between the contained amounts of component A and component B is 5 wt% or less.

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 suitable for coating by an inkjet method (hereinafter, referred to as inkjet coating).

As the liquid crystal alignment film, a so-called polyimide-based liquid crystal alignment film is widely used which is obtained by applying and baking a liquid crystal alignment agent containing a polyimide precursor such as polyamic acid or a solution of a soluble polyimide as a main component. As a method for forming such a liquid crystal alignment film, inkjet coating is currently mainstream instead of spin coating, flexo printing, etc. so far.

Ink jet coating is a method in which fine droplets are dropped on a substrate to form a film by wetting and spreading of a liquid. By this method, efficient use of the liquid crystal aligning agent in the liquid crystal panel manufacturing process becomes possible, the production efficiency of the liquid crystal panel can be improved, and the cost reduction of the liquid crystal panel can be achieved.

The liquid crystal aligning agent used for inkjet coating is required to have a small film thickness unevenness inside the coating surface and to have a high film forming accuracy in the periphery of the coating. At the same time, it is also important that the organic solvent in the liquid crystal alignment agent does not damage the inkjet head and the peripheral members when the ink is ejected from the inkjet device.

In order to achieve the various requirements described above, liquid crystal aligning agents for ink jet coating using appropriate combinations of various solvents have been proposed (see Patent Document 1 and Patent Document 2). With this, further improvement of the characteristics is desired.

Japanese Patent Application No. 2013-507817 Japanese Patent Application No. 2014-529512

In view of the above-mentioned background, the present invention aims to provide a liquid crystal aligning agent most suitable for inkjet coating, by improving various properties required for inkjet coating.

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 an organic solvent and at least one polymer selected from a polyimide precursor which is a reaction product of a tetracarboxylic acid derivative and a diamine and a polyimide which is an imidized product thereof, wherein the organic solvent is component A: At least one component B selected from γ-butyrolactone and γ-valerolactone: containing dipropylene glycol dimethyl ether, the content of each of the components A and B is 25% by weight or less, and the content of the components A and B Liquid crystal aligning agent characterized in that the amount difference is 5% by weight or less.

By using the liquid crystal aligning agent according to the present invention, it is possible to obtain a liquid crystal aligning film having a small film thickness unevenness inside the coated surface and a high film forming accuracy in the peripheral portion of the coating when using the liquid crystal aligning agent When the ink is discharged from the ink jet apparatus, the ink jet head and peripheral members are not damaged, and as a result, it is possible to contribute to the stability of the liquid crystal display element production.

Hereinafter, various requirements of the present invention will be described in detail.
<Organic solvent and its composition>
The liquid crystal aligning agent of the present invention contains the following components A and B as an organic solvent.
Component A: At least one selected from γ-butyrolactone and γ-valerolactone B component: Dipropylene glycol dimethyl ether The organic solvent of the A component dissolves the polymer contained in the liquid crystal aligning agent of the present invention At the same time, the ink jet head and peripheral members of the ink jet coating apparatus are not easily adversely affected. Preferred as the A component is γ-butyrolactone.
The solvent of component B is one that improves the wetting and spreading properties when the liquid crystal aligning agent of the present invention is applied on a substrate or a film.
The content of each of the component A and the component B is 25% by weight or less, and the content difference between the component A and the component B is 5% by weight or less.
Further, it is preferable from the viewpoint of solubility that the component C further contains at least one selected from N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone and N-butyl-2-pyrrolidone.
The organic solvent of component C is a component that dissolves the polymer contained in the liquid crystal aligning agent of the present invention. Preferred specific examples include N-methyl-2-pyrrolidone and N-ethyl-2-pyrrolidone.
Moreover, when using C component, the content is 35 weight% or less with respect to the weight of the whole liquid crystal aligning agent, and 30 weight% or less is more preferable.

<Polymer>
The polymer contained in the liquid crystal aligning agent of the present invention is at least one polymer selected from a polyimide precursor which is a reaction product of a tetracarboxylic acid derivative and a diamine and a polyimide which is an imidized product thereof.
The structure of the polymer is not particularly limited, and the tetracarboxylic acid derivative and the diamine to be described later can be optionally selected according to the characteristics of the liquid crystal aligning agent to be obtained. Among them, the side of the following formula [1-1] A polymer containing a chain structure is preferred from the viewpoint of solubility and the like.

In the formula [1-1], Y ¹ and Y ³ are each independently a single bond,-(CH ₂ ) _a- (a is an integer of 1 to 15), -O-, -CH ₂ O- And at least one selected from the group consisting of -COO- and -OCO-.

Y ² represents a single bond or-(CH ₂ ) _b- (b is an integer of 1 to 15) (provided that Y ¹ or Y ³ is a single bond,-(CH ₂ ) _a- ² is a single bond, Y ¹ is at least one selected from the group consisting of -O-, -CH ₂ O-, -COO- and -OCO-, and / or Y ³ is -O-, In the case of at least one member selected from the group consisting of -CH ₂ O-, -COO- and -OCO-, Y ² is a single bond or-(CH ₂ ) _b- ).

Y ⁴ represents at least one kind of divalent cyclic group selected from the group consisting of a benzene ring, a cyclohexane ring and a heterocycle, or a divalent organic group having 17 to 51 carbon atoms having a steroid skeleton, And hydrogen is an alkyl group of 1 to 3 carbon atoms, an alkoxy group of 1 to 3 carbon atoms, a fluorine-containing alkyl group of 1 to 3 carbon atoms, a fluorine-containing alkoxy group of 1 to 3 carbon atoms or a fluorine atom It may be substituted.

Y ⁵ represents at least one cyclic group selected from the group consisting of benzene ring, cyclohexane ring and heterocyclic ring, and any hydrogen atom on these cyclic groups is an alkyl group having 1 to 3 carbon atoms, 1 carbon atom It may be substituted by an alkoxy group of to 3, a fluorine-containing alkyl group having 1 to 3 carbon atoms, a fluorine-containing alkoxy group having 1 to 3 carbon atoms, or a fluorine atom.

Y ⁶ represents an alkyl group having 1 to 18 carbon atoms, an alkenyl group having 2 to 18 carbon atoms, a fluorine-containing alkyl group having 1 to 18 carbon atoms, an alkoxy group having 1 to 18 carbon atoms and a fluorine-containing alkoxy having 1 to 18 carbon atoms This represents at least one selected from the group consisting of groups. n is an integer of 0 to 4;
In order to introduce the above-mentioned side chain structure into a polymer, there is mentioned a method of using one obtained by introducing the above-mentioned side chain structure into a tetracarboxylic acid derivative or diamine which is a material of the polymer. Among them, it is preferable from the viewpoint of easiness of synthesis and the like to use a diamine into which the side chain structure is introduced.
Preferred specific examples of the side chain structure include the following formulas (S1-1) to (S1-22).

Furthermore, when a process such as ultraviolet irradiation is included in the manufacturing process of the liquid crystal display element, it is preferable to introduce a photoreactive side chain that causes a photoreaction by ultraviolet light of a specific wavelength.

The photoreactive side chain includes a side chain structure of the following formula [VII]. The side chain structure of the formula [VII] has a radical generating structure. In the radical generating structure, radicals are generated by decomposition upon irradiation with ultraviolet light.

In the above-mentioned formula [VII], Ar represents at least one aromatic hydrocarbon group selected from the group consisting of phenylene, naphthylene and biphenylene, and the hydrogen atom of their ring may be substituted by a halogen atom. Since Ar to which a carbonyl is bound is involved in the absorption wavelength of ultraviolet light, when the wavelength is increased, a structure with a long conjugate length such as naphthylene or biphenylene is preferable. On the other hand, when Ar has a structure such as naphthylene or biphenylene, the solubility may be deteriorated, and in this case, the degree of difficulty of synthesis becomes high. If the wavelength of ultraviolet light is in the range of 250 nm to 380 nm, sufficient characteristics can be obtained even with a phenyl group, so Ar is most preferably a phenyl group.

In the above Ar, the aromatic hydrocarbon group may be provided with a substituent. As an example of the substituent here, an electron donative organic group such as an alkyl group, a hydroxyl group, an alkoxy group, an amino group and the like is preferable.

In the above Formula [VII], R ₁ and R ₂ each independently represent an alkyl group having 1 to 10 carbon atoms, an alkoxy group, a benzyl group or a phenethyl group. In the case of an alkyl group or an alkoxy group, a ring may be formed by R ₁ and R ₂ .

In the above Formula [VII], T ₁ and T ₂ each independently represent a single bond, -O-, -COO-, -OCO-, -NHCO-, -CONH-, -NH-, -CH _{2 O -, - N (CH} 3) -, - CON (CH 3) - or an -N _(CH 3) CO- linking group.

Further, in the formula [VII], S represents a single bond or an alkylene group having 1 to 20 carbon atoms which is substituted or unsubstituted by a fluorine atom. The alkylene group -CH ₂ -or -CF ₂ -may be optionally substituted by -CH = CH-, and when any of the following groups are not adjacent to each other, these groups may be -O-, -COO-, -OCO-, -NHCO-, -CONH-, -NH-, divalent carbon ring, divalent heterocyclic ring.

Further, in the formula [VII], Q represents a structure selected from the following formula (1d).

In the above formula (1d), R represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. R ₃ represents —CH ₂ —, —NR—, —O— or —S—.

In the above Formula [VII], Q is preferably an electron-donating organic group, and is preferably an alkyl group, a hydroxyl group, an alkoxy group, an amino group or the like as mentioned in the example of Ar above. When Q is an amino derivative, a problem such as a carboxylic acid group generated and an amino group forming a salt may occur during polymerization of a polyamic acid which is a precursor of polyimide, so a hydroxyl group or an alkoxy group is generated. Is more preferred.

<Tetracarboxylic acid derivative>
The polymer contained in the liquid crystal aligning agent of the present invention is at least one polymer selected from a polyimide precursor obtained from the reaction of a tetracarboxylic acid derivative and a diamine and a polyimide which is an imidized product thereof. 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 tetracarboxylic acid derivatives, those represented by the following formula (3) are preferable.

In Formula (3), the structure of X ₁ is not particularly limited. Specific examples include the following formulas (X1-1) to (X1-42). Preferred are (X1-1), (X1-2), (X1-5), (X1-7), (X1-8), (X1-10), (X1-11), and (X1-26). And (X1-27), (X1-33), (X1-38) and (X1-40).

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). From the viewpoint of liquid crystal alignment and polymerization reactivity, (X1-1-1) and (X1-1-2) are particularly preferable.

<Diamine>
The diamine used for manufacture of a polyimide precursor is represented by following formula (4).

In the above formula (4), 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 the said Formula (4) is not specifically limited. As a preferable structure, the above-mentioned diamine containing the side chain structure of the formula [1-1] can be mentioned. Specific examples thereof include (Y-178), (Y-180) and (Y-181).
Besides, it is possible to use diamine having any structure. Specific examples include the following (Y-1) to (Y-177).
(Y-27), (Y-28), (Y-38), (Y-71) from the viewpoint of easiness of production of polyimide precursor, stability of liquid crystal aligning agent, characteristics as liquid crystal aligning film, etc. (Y-72), (Y-76), (Y-77), (Y-80), (Y-81), (Y-82), (Y-158), (Y-159), (Y Y-160), (Y-161) and (Y-169) to (Y-188) are preferable.

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.

<Polyamic acid>
The polyamic acid which is a polyimide precursor used for this invention can be manufactured by the method shown below. Specifically, a tetracarboxylic dianhydride and a diamine 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 12 hours. Can be synthesized by

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 manufacturing from polyamic acid
The polyamic acid ester can be synthesized by esterification of 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 above three methods for producing polyamic acid, a high molecular weight polyamic acid ester can be obtained, and therefore the production method of the above (1) or (2) is particularly preferable.

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 polyimide imidization rate used in the present invention is not limited to 100%. From the viewpoint of electrical characteristics, 20 to 99% is preferable. 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 the form of a solution in which a polymer containing a specific polymer is dissolved in an organic solvent containing a specific 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 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.

<Other solvent>
The solvent in the liquid crystal aligning agent of the present invention preferably contains the components A and B and further contains a component C, but may contain other solvents. As other solvents, a solvent which dissolves a polyimide precursor and a polyimide (also referred to as a good solvent), a solvent which improves the coating property and surface smoothness of a liquid crystal alignment film when a liquid crystal aligning agent is applied (also a poor solvent) Is preferably used. Specific examples of other solvents are listed below, but are not limited to these examples.

Specific examples of good solvents include 1,3-dimethylimidazolidinone, N, N-dimethylformamide, N, N-dimethylacetamide, dimethylsulfoxide, methyl ethyl ketone, cyclohexanone, cyclopentanone, 3-methoxy-N, N-dimethyl Propanamide or 4-hydroxy-4-methyl-2-pentanone and the like can be mentioned.
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, you may use the solvent represented by a following formula as a poor solvent.

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.
In addition, when the solubility of the polyimide precursor and the polyimide contained in the liquid crystal alignment agent in the solvent is high as the poor solvent, the solvents represented by the following [D-1] to the formula [D-3] are used Also good.

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.
Examples of the crosslinkable compound having an epoxy group include bisphenolacetone glycidyl ether, phenol novolac epoxy resin, cresol novolac epoxy resin, triglycidyl isocyanurate, tetraglycidyl aminodiphenylene, tetraglycidyl-m-xylene diamine, tetraglycidyl-1 , 3-Bis (aminoethyl) cyclohexane, tetraphenyl glycidyl ether ethane, triphenyl glycidyl ether ethane, bisphenol hexafluoroacetodiglycidyl ether, 1,3-bis (1- (2,3-epoxypropoxy) -1-trile Fluoromethyl-2,2,2-trifluoromethyl) benzene, 4,4-bis (2,3-epoxypropoxy) octafluorobiphenyl, triglycidyl-p- Minophenol, tetraglycidyl metaxylene diamine, 2- (4- (2,3-epoxypropoxy) phenyl) -2- (4- (1,1-bis (4- (2,3-epoxypropoxy) phenyl) ethyl) ) Phenyl) propane or 1,3-bis (4- (1- (4- (2,3-epoxypropoxy) phenyl) -1- (4- (1- (4- (2,3-epoxypropoxy) phenyl) phenyl) And -1-) methyl ethyl) phenyl) ethyl) phenoxy) 2-propanol and the like.
Specifically, the crosslinkable compound having an oxetane group is represented by the formula [4a] to the formula [4k] published on pages 58 to 59 of International Publication WO 2011/132751 (published on 2011.10.27). Crosslinkable compounds may be mentioned.
Specific examples of the crosslinkable compound having a cyclocarbonate group include those represented by the formulas [5-1] to [5] listed on pages 76 to 82 of International Publication WO 2012/014898 (2012.2.2 published). And a crosslinkable compound represented by the formula -42].
Specific examples of the crosslinkable compound having at least one substituent selected from the group consisting of a hydroxyl group and an alkoxyl group include pages 62 to 66 of International Publication WO 2011/132751 (published on 2011.10.27). The crosslinkable compounds of the formulas [6-1] to [6-48] listed in
Among the above-mentioned crosslinkable compounds, the following compounds are particularly 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.

<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 The present invention will be more specifically described below by way of Examples, but the present invention is not limited thereto. The symbol of the compound in the following and the measuring method of each characteristic are as follows.

<Tetracarboxylic acid dianhydride>
CBDA: 1,2,3,4, -cyclobutanetetracarboxylic acid dianhydride
BODA: bicyclo [3,3,0] octane-2,4,6,8-tetracarboxylic acid dianhydride DSDA: 3,3 ', 4,4'-diphenyl sulfone tetracarboxylic acid dianhydride PMDA: pyromellitic Acid anhydride

<Diamine>
DA-1: p-phenylenediamine DA-2: 4, 4-diaminodiphenylmethane DA-3: 3,5-diaminobenzoic acid DA-4: 3,5-diamino-N- (pyridin-3-ylmethyl) benzamide DA -5: 4,4 '-[Isopropylidenebis (p-phenyleneoxy)] dianiline DA-6: diamine DA-7 of the following formula DA-6: 1- (4- (2- (2,4-diaminophenoxy) ) Ethoxy) phenyl) -2-hydroxy-2-methylpropanone DA-8: 1,3-diamino-4- [4- (trans-4-n-heptylcyclohexyl) phenoxy] benzene DA-9: 1,3 -Diamino-4- [trans-4- [trans-4- (pentylcyclohexyl) -cyclohexyl] phenoxy] benzene

<Structure of DA-1 to DA-9>

<Additives>
TM-BIP-A: 2,2'-bis (4-hydroxy-3,5-dihydroxymethylphenyl) propane

<Organic solvent>
NMP: 1-methyl-2-pyrrolidone
NEP: 1-ethyl-2-pyrrolidone GBL: γ-butyrolactone BCS: butyl cellosolve PB: 1-butoxy-2-propanol DME: dipropylene glycol dimethyl ether DIBK: diisobutyl ketone In the examples, molecular weight and imidation ratio of polyamic acid and polyimide , Was evaluated as follows.

<Molecular weight measurement>
For the molecular weight of polyamic acid and polyimide, a room temperature gel permeation chromatography (GPC) apparatus (GPC-101) manufactured by Showa Denko K. K. and columns manufactured by Shodex (KD-803, KD-805) were used. The measurement conditions are as follows.
Column temperature: 50 ° C
Eluent: N, N'-dimethylformamide (Additive: 30 mmol / L of lithium bromide-hydrate (LiBr · H2O), 30 mmol / L of phosphoric acid / anhydrous crystal (o-phosphoric acid), tetrahydrofuran (THF) ) 10ml / L)
Flow rate: 1.0 ml / min
Standard samples for preparing a calibration curve: TSK standard polyethylene oxide (molecular weight: approximately 900,000, 150,000, 100,000, 30,000) manufactured by Tosoh Corp., and polyethylene glycol (molecular weight: approximately 12,000, 4 manufactured by Polymer Laboratory) , 000, 1,000).

<Measurement of imidation ratio>
20 mg of polyimide powder is placed in an NMR sample tube (manufactured by Kusano Scientific Co., Ltd., NMR sampling tube standard φ5), and 0.53 ml of deuterated dimethyl sulfoxide (DMSO-d6, 0.05% TMS (tetramethylsilane) mixture) is added The solution was sonicated and completely dissolved. For this solution, proton NMR at 500 MHz was measured using an NMR meter (JNW-ECA500) manufactured by Nippon Denshi Datum Co., Ltd. The imidation ratio is determined using a proton derived from a structure which 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 9.0 to 11.0 ppm. It calculated | required by the following Numerical formula (1) using an integral value.

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

In the above formula (1), x is a proton peak integrated value derived from the NH group of the amic acid, y is a peak integrated value of the reference proton, and α is the NH group of the amic acid in the case of polyamic acid (imidation ratio is 0%) It is the number ratio of reference protons to one proton.

Synthesis Example 1
BODA (22.27 g, 89 mmol), DA-7 (14.70 g, 44.5 mmol), DA-4 (12.94 g, 53.4 mmol), DA-9 (19.34 g, 44.5 mmol), DA- 8 (13.55 g, 35.6 mmol) are mixed in NMP (331.2 g) and reacted at 60 ° C. for 3 hours, and then CBDA (16.93 g, 86.3 mmol) and NMP (67.2 g) In addition, reaction was carried out at 40 ° C. for 15 hours to obtain a polyamic acid solution (a). The number average molecular weight of this polyamic acid solution (a) was 22,000, and the weight average molecular weight was 58,000. NMP is added to this polyamic acid solution (a) (498.13 g) to dilute the content of the polyamic acid solution (a) to 10% by mass, and then acetic anhydride (90.87 g) as an imidization catalyst, And pyridine (28.16 g) were added and reacted at 70 ° C. for 3.5 hours. The reaction solution was poured into methanol (5,000 ml) and the resulting precipitate was filtered off. The precipitate was washed with methanol and dried under reduced pressure at 100 ° C. to obtain polyimide (A). The imidation ratio of this polyimide (A) was 72%.

Synthesis Example 2
BODA (23.02 g, 92 mmol), DA-3 (14.0 g, 92 mmol), DA-5 (22.66 g, 55.2 mmol), DA-8 (14.01 g, 36.8 mmol) with NMP (294. After mixing in 73 g) and reacting at 60 ° C. for 1 hour, CBDA (6.68 g, 34.0 mmol) and NMP (26.7 g) are added and allowed to react at 20 ° C. for 1 hour. .78 g (55.2 mmol) and NMP (79.11 g) were added and reacted at 40 ° C. for 2 hours to obtain a polyamic acid solution (b). The number average molecular weight of this polyamic acid solution (b) was 17,000, and the weight average molecular weight was 45,000. After adding NMP to this polyamic acid solution (b) (500.69 g) and diluting so that content of a polyamic acid solution (b) may be 6.5 mass%, acetic anhydride (93.93 g as an imidation catalyst is carried out. And pyridine (72.77 g) were added and reacted at 75 ° C. for 3.5 hours. The reaction solution was poured into methanol (5,000 ml) and the resulting precipitate was filtered off. The precipitate was washed with methanol and dried under reduced pressure at 100 ° C. to obtain polyimide (B). The imidation ratio of this polyimide (B) was 74%.

Synthesis Example 3
BODA (25.02 g, 100 mmol), DA-1 (8.65 g, 80 mmol), DA-6 (6.83 g, 20 mmol), DA-8 (38.6 g, 100 mmol) in NMP (214.2 g) After mixing and reacting at 60 ° C. for 3 hours, CBDA (19.61 g, 100 mmol) and NMP (178.5 g) were added and reacted at 40 ° C. for 15 hours to obtain a polyamic acid solution (c). The number average molecular weight of this polyamic acid solution (c) was 23,000, and the weight average molecular weight was 60,000. NMP is added to this polyamic acid solution (c) (450.0 g) to dilute it so that the content of the polyamic acid solution (a) is 10% by mass, then acetic anhydride (103.6 g) as an imidization catalyst, And pyridine (32.11 g) were added and reacted at 70 ° C. for 3.5 hours. The reaction solution was poured into methanol (3,600 ml) and the resulting precipitate was filtered off. The precipitate was washed with methanol and dried under reduced pressure at 100 ° C. to obtain polyimide (C). The imidation ratio of this polyimide (C) was 69%.

Synthesis Example 4
BODA (25.02 g, 100 mmol), DA-7 (6.60 g, 20 mmol), DA-2 (23.79 g, 120 mmol), DA-9 (26.1 g, 60 mmol) in NMP (225.9 g) After mixing and reacting at 60 ° C. for 3 hours, CBDA (19.61 g, 100 mmol) and NMP (178.5 g) were added, and reacted at 40 ° C. for 15 hours to obtain a polyamic acid solution (d). The number average molecular weight of this polyamic acid solution (d) was 24,000, and the weight average molecular weight was 62,000. NMP is added to this polyamic acid solution (d) (450.0 g) to dilute the content of the polyamic acid solution (d) to 10% by mass, and then acetic anhydride (90.9 g) as an imidization catalyst, And pyridine (28.17 g) were added and reacted at 70 ° C. for 3.5 hours. The reaction solution was poured into methanol (3,600 ml) and the resulting precipitate was filtered off. The precipitate was washed with methanol and dried under reduced pressure at 100 ° C. to obtain polyimide (D). The imidation ratio of this polyimide (D) was 73%.

Synthesis Example 5
BODA (25.02 g, 100 mmol), DA-3 (12.17 g, 80 mmol), DA-4 (14.53 g, 60 mmol), DA-8 (22.83 g, 60 mmol) in NMP (198.17 g) After mixing and reacting at 60 ° C. for 3 hours, PMDA (8.72 g. 40 mmol) and NMP (34.9 g) were added and allowed to react at 40 ° C. for 3 hours. Finally, CBDA (11.76 g, 60 mmol) and NMP (147.15 g) were added and reacted for 15 hours to obtain a polyamic acid solution (e). The number average molecular weight of this polyamic acid solution (e) was 25,000, and the weight average molecular weight was 65,000. NMP is added to this polyamic acid solution (e) (450.0 g) to dilute the content of the polyamic acid solution (d) to 10% by mass, and then acetic anhydride (96.7 g) as an imidization catalyst, And pyridine (29.97 g) were added and reacted at 70 ° C. for 3.5 hours. The reaction solution was poured into methanol (3,600 ml) and the resulting precipitate was filtered off. The precipitate was washed with methanol and dried under reduced pressure at 100 ° C. to obtain polyimide (E). The imidation ratio of this polyimide (E) was 72%.

Example 1
NEP (198 g) is added to the polyimide (A) (13.5 g) obtained in Synthesis Example 1 and the polyimide (B) (13.5 g) obtained in Synthesis Example 2 and dissolved by stirring at 70 ° C. for 20 hours I did. NEP (17.91 g), GBL (151.2 g), PB (180 g), DME (144 g), and TM-BIP-A (1.89 g) were added to this solution and stirred at 25 ° C. for 2 hours. This solution was filtered through a filter with a pore size of 1 μm to prepare a liquid crystal aligning agent [A] of the present invention.

Example 2
NMP (150.73 g) is added to the polyimide (A) (13.3 g) obtained in Synthesis Example 1 and the polyimide (B) (13.3 g) obtained in Synthesis Example 2 and stirred at 70 ° C. for 20 hours Dissolved. NMP (65.30 g), GBL (115.02 g), BCS (251.6 g), DME (107.8 g), TM-BIP-A (1.86 g) are added to this solution, and 2 hours at 25 ° C. It stirred. This solution was filtered through a filter with a pore size of 1 μm to prepare a liquid crystal aligning agent [B] of the present invention.

Example 3
NMP (150.73 g) is added to the polyimide (C) obtained in Synthesis Example 3 (13.3 g) and the polyimide (E) obtained in Synthesis Example 5 (13.3 g) and stirred at 70 ° C. for 20 hours Dissolved. NMP (65.30 g), GBL (115.02 g), BCS (251.6 g), DME (107.8 g), TM-BIP-A (1.86 g) are added to this solution, and 2 hours at 25 ° C. It stirred. This solution was filtered through a filter with a pore size of 1 μm to prepare a liquid crystal aligning agent [C] of the present invention.

Example 4
NEP (198 g) is added to the polyimide (D) obtained in Synthesis Example 4 (13.5 g) and the polyimide (E) obtained in Synthesis Example 5 (13.5 g) and dissolved by stirring at 70 ° C. for 20 hours I did. NEP (17.91 g), GBL (151.2 g), PB (180 g), DME (144 g), and TM-BIP-A (1.86 g) were added to this solution and stirred at 25 ° C. for 2 hours. This solution was filtered through a filter with a pore size of 1 μm to prepare a liquid crystal aligning agent [D] of the present invention.

Example 5
NEP (150.73 g) is added to the polyimide (A) (13.3 g) obtained in Synthesis Example 1 and the polyimide (E) (13.3 g) obtained in Synthesis Example 5 and stirred at 70 ° C. for 20 hours Dissolved. NEP (65.30 g), GBL (115.02 g), BCS (251.6 g), DME (107.8 g), TM-BIP-A (1.86 g) are added to this solution, and 2 hours at 25 ° C. It stirred. This solution was filtered through a filter with a pore size of 1 μm to prepare a liquid crystal aligning agent [E] of the present invention.

Comparative Example 1
NEP (198 g) is added to the polyimide (A) (13.5 g) obtained in Synthesis Example 1 and the polyimide (B) (13.5 g) obtained in Synthesis Example 2 and dissolved by stirring at 70 ° C. for 20 hours I did. To this solution, NEP (169.11 g), PB (216 g), DME (108 g), and TM-BIP-A (1.89 g) were added, and the mixture was stirred at 25 ° C. for 2 hours. This solution was filtered through a filter with a pore size of 1 μm to prepare a liquid crystal aligning agent [F].

Comparative Example 2
NEP (148.59 g) was added to the polyimide (A) (10.13 g) obtained in Synthesis Example 1 and the polyimide (B) (10.13 g) obtained in Synthesis Example 2 and stirred at 70 ° C. for 20 hours. Dissolved. To this solution, NEP (261.67 g), PB (287.95 g), and TM-BIP-A (1.42 g) were added, and the mixture was stirred at 25 ° C. for 2 hours. This solution was filtered through a filter with a pore size of 1 μm to prepare a liquid crystal aligning agent [G].

Comparative Example 3
NEP (195.07 g) is added to the polyimide (A) (13.3 g) obtained in Synthesis Example 1 and the polyimide (B) (13.3 g) obtained in Synthesis Example 2 and stirred at 70 ° C. for 20 hours Dissolved. To this solution, NEP (202.08 g), PB (212.79 g), DIBK (70.93 g), TM-BIP-A (1.86 g) were added, and the mixture was stirred at 25 ° C. for 2 hours. This solution was filtered through a filter with a pore size of 1 μm to prepare a liquid crystal aligning agent [H].

[Method of formation and evaluation of coating film]
The prepared liquid crystal aligning agent was applied to a substrate by an ink jet method, predrying and main baking were performed to form a coating film. The evaluation of the ink jet coating was performed using an ink jet apparatus (type IJ-1021) manufactured by Shibaura Mechatronics, Ltd. under the following conditions.
Ink jet application conditions:
Head: H18, H1A
Nozzle No. / Head = 256
Head Nozzle Pitch: 396.88um
Head Offset: 198.43 um
Scan count: 2 Scan
Drop pitch (X) in the direction of the head array: 99.22 um
Stage speed: 512 mm / sec, frequency: 4000 Hz
Drop pitch (Y) of the stage movement direction: 128um
Coating pattern setting value: 80 mm x 80 mm
Film thickness: 1000 Å.
Substrate: In the evaluation of the Halo area, a glass substrate with a Cr or ITO electrode on the entire surface on one side of 100 × 100 mm was used. A TFT substrate was used for evaluation of unevenness (C / H unevenness) around the contact hole.
Standing time from the end of application to predrying: 45 seconds Predrying: The substrate was placed on a 1 mm high pin placed on a hot plate set at 90 ° C. and dried for 40 seconds.
Final firing: 230 ° C / 20 minutes (IR oven)

<Evaluation method of Halo area>
Evaluation of the Halo area at the edge of the liquid crystal alignment film is observed with an optical microscope (ECLIPSE L300N, manufactured by Nikon Corp.) color tone change (film thickness unevenness) at the coating edge at the top, bottom, left, and right with respect to the coating direction. It did by doing. Specifically, the magnification was observed at 2.5 times with an optical microscope, and the length of the color tone change (film thickness unevenness) of the obtained coating film image was measured. All coating images are obtained at the same magnification. In addition, those with an average value of 7 mm or more in color tone change (film thickness unevenness) at the coating film edge at lower, left, and right are marked x, those with 6 mm to 5 mm are marked Δ and those less than 5 mm are marked 〇.

<Evaluation method of C / H unevenness>
The surface of the coating film obtained above is observed with an optical microscope at a magnification of 5 times, and the number of unevenness around C / H is 20% or less of the C / H number in the field of view “○” , More than that "X".

The following table shows the evaluation results of the liquid crystal aligning agent obtained in Examples 1 to 5 and Comparative Examples 1 to 3.

The liquid crystal aligning agent of the present invention can solve display unevenness in the vicinity of the frame by improving the adhesion between the sealing agent and the liquid crystal alignment film in a narrow frame liquid crystal display element capable of securing a large number of display surfaces. It is useful.

Claims (7)

A liquid crystal aligning agent containing an organic solvent and at least one polymer selected from a polyimide precursor which is a reaction product of a tetracarboxylic acid derivative and a diamine and a polyimide which is an imidized product thereof, wherein the organic solvent is component A: At least one component B selected from .gamma.-butyrolactone and .gamma.-valerolactone: containing at least one component selected from dipropylene glycol dimethyl ether and diacetone alcohol, and the content of each of components A and B is 25% by weight or less What is claimed is: 1. A liquid crystal aligning agent characterized in that the content difference between the component A and the component B is 5% by weight or less. Furthermore, it contains at least one selected from N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, and N-butyl-2-pyrrolidone as the C component, and these C components are 40% of the total weight of the liquid crystal aligning agent. The liquid crystal aligning agent according to claim 1, characterized in that it is not more than% by weight. The liquid crystal aligning agent of Claim 1 or 2 in which the said polymer contains the side chain structure of following formula [1-1].

In the formula [1-1], Y ¹ and Y ³ are each independently a single bond,-(CH ₂ ) _a- (a is an integer of 1 to 15), -O-, -CH ₂ O- And at least one selected from the group consisting of -COO- and -OCO-.
Y ² represents a single bond or-(CH ₂ ) _b- (b is an integer of 1 to 15) (provided that Y ¹ or Y ³ is a single bond,-(CH ₂ ) _a- ² is a single bond, Y ¹ is at least one selected from the group consisting of -O-, -CH ₂ O-, -COO- and -OCO-, and / or Y ³ is -O-, In the case of at least one member selected from the group consisting of -CH ₂ O-, -COO- and -OCO-, Y ² is a single bond or-(CH ₂ ) _b- ).
Y ⁴ represents at least one kind of divalent cyclic group selected from the group consisting of a benzene ring, a cyclohexane ring and a heterocycle, or a divalent organic group having 17 to 51 carbon atoms having a steroid skeleton, And hydrogen is an alkyl group of 1 to 3 carbon atoms, an alkoxy group of 1 to 3 carbon atoms, a fluorine-containing alkyl group of 1 to 3 carbon atoms, a fluorine-containing alkoxy group of 1 to 3 carbon atoms or a fluorine atom It may be substituted.
Y ⁵ represents at least one cyclic group selected from the group consisting of benzene ring, cyclohexane ring and heterocyclic ring, and any hydrogen atom on these cyclic groups is an alkyl group having 1 to 3 carbon atoms, 1 carbon atom It may be substituted by an alkoxy group of to 3, a fluorine-containing alkyl group having 1 to 3 carbon atoms, a fluorine-containing alkoxy group having 1 to 3 carbon atoms, or a fluorine atom.
Y ⁶ represents an alkyl group having 1 to 18 carbon atoms, an alkenyl group having 2 to 18 carbon atoms, a fluorine-containing alkyl group having 1 to 18 carbon atoms, an alkoxy group having 1 to 18 carbon atoms and a fluorine-containing alkoxy having 1 to 18 carbon atoms This represents at least one selected from the group consisting of groups. n is an integer of 0 to 4; The liquid crystal aligning agent of any one of Claim 1 to 3 in which the said tetracarboxylic dianhydride component contains the tetracarboxylic dianhydride represented by following formula [3].

In the formula [3], X ₁ is a tetravalent organic group having 4 to 13 carbon atoms, and contains a non-aromatic cyclic hydrocarbon group having 4 to 10 carbon atoms. The liquid crystal aligning agent according to claim 4, wherein X ₁ is a structure represented by the following formula.

R ₃ to R _6, R _{24 and} R ₂₅ each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, It is a C 1-6 monovalent organic group containing a fluorine atom, or a phenyl group. The liquid crystal aligning film obtained from the liquid crystal aligning agent in any one of Claims 1-5. A liquid crystal display device comprising the liquid crystal alignment film according to claim 6.