TWI698489B - Liquid crystal alignment agent, liquid crystal alignment film and liquid crystal display element - Google Patents

Abstract

The present invention provides a liquid crystal alignment agent which has excellent printability by an inkjet coating method and can provide a liquid crystal alignment film with excellent electrical characteristics. The liquid crystal alignment agent provided by the present invention contains at least one polymer selected from the group consisting of polyamide acid, polyimide and polyamide ester obtained by reacting tetracarboxylic dianhydride and diamine (A) and a solvent, and the solvent contains at least one selected from the group consisting of diethylene glycol propyl methyl ether and diethylene glycol butyl methyl ether.

Description

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

The invention relates to a liquid crystal alignment agent, a liquid crystal alignment film and a liquid crystal display element. In more detail, the present invention particularly relates to a liquid crystal alignment agent capable of providing a liquid crystal alignment film with good coatability in an inkjet coating method, and a liquid crystal display element with excellent electrical characteristics.

Currently, as a liquid crystal display element, the following TN type liquid crystal display element having a so-called twisted nematic (TN) type liquid crystal cell is known, which is provided with transparent indium oxide-tin oxide (Indium Tin Oxide, ITO), etc. On the surface of the substrate of the conductive film, a liquid crystal alignment film containing polyamide acid, polyimide, etc. is formed as a substrate for liquid crystal display elements. The two substrates are arranged facing each other, and a positive dielectric is formed in the gap between the substrates. A layer of electrically anisotropic nematic liquid crystal is formed into a sandwich structure unit, and the long axis of the liquid crystal molecule is continuously twisted by 90° from one substrate to the other substrate. In addition, a Super Twisted Nematic (STN) type liquid crystal display element with higher contrast and less viewing angle dependence than TN type liquid crystal display elements is under development. This STN type liquid crystal display element uses nematic liquid crystals doped with a chiral agent as an optically active material as the liquid crystal, and uses the long axis of the liquid crystal molecules to cross over 180° between the substrates to be in a continuously twisted state The resulting birefringence effect.

Furthermore, in recent years, a horizontal electric field type liquid crystal display element has been proposed in which two electrodes for driving liquid crystal are arranged in a comb-tooth shape on one of a pair of substrates, and an electric field parallel to the substrate surface is generated. Control liquid crystal molecules. This device is usually called In Plane Switching (IPS) type, and it is known that the viewing angle is excellent and wide. Especially when the IPS-type element and the optical compensation film are used together, the big feature is that the viewing angle characteristics can be further improved, and there is no gray-scale inversion or hue change, which is comparable to the Braun tube. Perspective.

In addition to these, a method called Multi-Domain Vertical Alignment (MVA) method, or pattern vertical alignment (Multi-Domain Vertical Alignment, MVA) method, in which liquid crystal molecules with negative dielectric anisotropy are vertically aligned on a substrate, has also been proposed. Patterned Vertical Alignment (PVA) type vertical alignment type liquid crystal display element (refer to Patent Document 1 and Non-Patent Document 1). These vertical alignment type liquid crystal display elements are excellent in viewing angles, contrast, etc., and they can also be excellent in terms of manufacturing steps without rubbing treatment during the formation of the liquid crystal alignment film.

In recent years, the popularity of LCD TVs has advanced, and a large-scale production line called the "seventh generation" is operating. In addition, it is also planned to build a larger "8th generation" production line. The advantages of using a large-scale production line to increase the size of the substrate include: since multiple panels are taken out from one substrate, the step time can be reduced and the cost can be reduced; or the size of the liquid crystal display element itself can be coped with. On the other hand, the disadvantage of increasing the size of the substrate is that it is difficult to ensure the uniformity of printing of the liquid crystal alignment agent over a large area. In particular, the following points can be cited: If a large-area film is formed using an offset printing machine that has been widely used in the past, defects in the electrical properties of the liquid crystal alignment film may occur due to poor printing of the liquid crystal alignment agent.

In order to solve the problem, it is being studied to use an inkjet coating method in the formation of a liquid crystal alignment film. The advantages of the inkjet coating method include: since the liquid crystal alignment agent used in printing is substantially equal to the amount of liquid applied in reality, it is expected that the amount of liquid crystal alignment agent used can be reduced. In addition, there is no need to exchange or wash the printing plate because it does not use the printing plate, which can reduce the time, labor, and cost for maintenance, or has flexibility that can correspond to a variety of panel sizes. [Prior Art Document] [Patent Document]

[Patent Document 1] Japanese Patent Laid-Open No. 11-258605 [Non-Patent Document]

[Non-Patent Document 1] "Liquid Crystals" Vol. 3 (No. 2) Page 117 (1999)

[The problem to be solved by the invention]

In order to manufacture liquid crystal display elements with high yield among large-scale substrates manufactured by large-scale production lines, in the inkjet coating method, a liquid crystal alignment agent with excellent printability is still continuously required. Furthermore, in recent years, the demand for improved display quality has become more stringent. For example, with regard to electrical characteristics, a liquid crystal alignment film having characteristics exceeding current characteristics is required.

The present invention is formed in view of the foregoing circumstances, and one of its objects is to provide a liquid crystal alignment agent that has particularly excellent printability by an inkjet coating method and can provide a liquid crystal alignment film with excellent electrical characteristics.

Still other objects and advantages of the present invention will be made clear from the following description. [Technical means to solve the problem]

First, the objectives and advantages of the present invention are achieved by a liquid crystal alignment agent, the liquid crystal alignment agent containing selected from the group consisting of polyamide acid, polyimide and polyamide ester At least one polymer (A) and a solvent. The liquid crystal alignment agent is characterized in that the solvent contains at least one selected from the group consisting of diethylene glycol propyl methyl ether and diethylene glycol butyl methyl ether.

Second, the objectives and advantages of the present invention are achieved by a liquid crystal display element, which includes a liquid crystal alignment film obtained from the liquid crystal alignment agent. [Effects of the invention]

The liquid crystal alignment agent of the present invention is particularly excellent in coating properties when used in an inkjet coating method, and therefore can improve the product yield in the manufacturing steps of a large-scale production line. In addition, the liquid crystal alignment film obtained from the liquid crystal alignment agent of the present invention has excellent electrical properties and is suitable for application to liquid crystal display elements.

Hereinafter, the present invention will be described in detail.

The liquid crystal alignment agent of the present invention contains at least one polymer (A) selected from the group consisting of polyamide acid, polyimide, and polyamide ester as a polymer component, and is prepared as the polymer (A) A liquid composition dispersed or dissolved in a solvent. "Polymer (A)" <Polyamic acid>

The polyamide in the present invention can be obtained by reacting tetracarboxylic dianhydride and diamine. (Tetracarboxylic dianhydride)

Examples of the tetracarboxylic dianhydride used in the synthesis of the polyamide acid include aliphatic tetracarboxylic dianhydride, alicyclic tetracarboxylic dianhydride, and aromatic tetracarboxylic dianhydride. As specific examples of these tetracarboxylic dianhydrides, the aliphatic tetracarboxylic dianhydrides include, for example, 1,2,3,4-butane tetracarboxylic dianhydride, etc.; and the alicyclic tetracarboxylic dianhydrides include, for example, ：1,2,3,4-Cyclobutanetetracarboxylic dianhydride, 2,3,5-Tricarboxycyclopentylacetic dianhydride, 1,3,3a,4,5,9b-hexahydro-5- (Tetrahydro-2,5-dioxo-3-furyl)-naphtho[1,2-c]furan-1,3-dione, 1,3,3a,4,5,9b-hexahydro -8-Methyl-5-(tetrahydro-2,5-dioxo-3-furyl)-naphtho[1,2-c]furan-1,3-dione, 3-oxabicyclo[ 3.2.1] Octane-2,4-dione-6-spiro-3'-(tetrahydrofuran-2',5'-dione), 5-(2,5-dioxotetrahydro-3- Furyl)-3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride, 3,5,6-tricarboxy-2-carboxymethylnorbornane-2:3,5:6-di Anhydride, 2,4,6,8-tetracarboxybicyclo[3.3.0]octane-2:4,6:8-dianhydride, 4,9-dioxatricyclic [5.3.1.0 ^2,6 ] ten Monoalkane-3,5,8,10-tetraketone, cyclohexanetetracarboxylic dianhydride, etc.; examples of aromatic tetracarboxylic dianhydrides include: pyromellitic dianhydride, etc.; in addition to this, it can also be used Tetracarboxylic dianhydride described in JP 2010-97188 A. In addition, the tetracarboxylic dianhydride may be used alone or in combination of two or more.

As the tetracarboxylic dianhydride used in the synthesis, it is preferable to include an alicyclic tetracarboxylic dianhydride from the viewpoints of transparency and solubility in solvents. In addition, among the alicyclic tetracarboxylic dianhydrides, it is preferable to contain 2,3,5-tricarboxycyclopentylacetic dianhydride, 1,3,3a,4,5,9b-hexahydro-5-( Tetrahydro-2,5-dioxo-3-furyl)-naphtho[1,2-c]furan-1,3-dione, 1,3,3a,4,5,9b-hexahydro- 8-Methyl-5-(tetrahydro-2,5-dioxo-3-furyl)-naphtho[1,2-c]furan-1,3-dione, 2,4,6,8 -At least one of the group consisting of tetracarboxybicyclo[3.3.0]octane-2:4,6:8-dianhydride and 1,2,3,4-cyclobutanetetracarboxylic dianhydride, Particularly preferably, it contains selected from 2,3,5-tricarboxycyclopentylacetic acid dianhydride, 2,4,6,8-tetracarboxybicyclo[3.3.0]octane-2:4,6:8-dianhydride , And at least one of the group consisting of 1,2,3,4-cyclobutanetetracarboxylic dianhydride.

In containing selected from 2,3,5-tricarboxycyclopentylacetic acid dianhydride, 2,4,6,8-tetracarboxybicyclo[3.3.0]octane-2:4,6:8-dianhydride, and When at least one of the group consisting of 1,2,3,4-cyclobutane tetracarboxylic dianhydride is used as the tetracarboxylic dianhydride, compared to the tetracarboxylic dianhydride used in the synthesis of polyamide acid The total amount of the acid dianhydride, the total content of these compounds is preferably 10 mol% or more, and more preferably 20 mol% to 100 mol%. (Diamine)

（式（D-1）中，X^I 及X^II 分別獨立地為單鍵、-O-、*-COO-、*-OCO-或*-NH-CO-（其中，帶有「*」的結合鍵與二胺基苯基鍵結），R^I 及R^II 分別獨立地為碳數1～3的烷二基，a為0或1，b為0～2的整數，c為1～20的整數，n為0或1，m為0或1；其中，a及b不會同時成為0，在X^I 為*-NH-CO-的情況下，n為0） 所表示的化合物等； 二胺基有機矽氧烷例如可列舉：1,3-雙(3-胺基丙基)-四甲基二矽氧烷等；除此以外，還可使用日本專利特開2010-97188號公報中記載的二胺。此外，這些二胺可單獨使用一種或者將兩種以上組合使用。Examples of the diamine used in the synthesis of polyamide acid include aliphatic diamines, alicyclic diamines, aromatic diamines, and diamino organosiloxanes. As specific examples of these diamines, aliphatic diamines include, for example, metaxylylenediamine, 1,3-propanediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine Etc.; Examples of alicyclic diamines include: 1,4-diaminocyclohexane, 4,4'-methylenebis(cyclohexylamine), 1,3-bis(aminomethyl)cyclohexyl Alkanes, etc.; examples of aromatic diamines include p-phenylenediamine, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylsulfide, 1,5-diamino Naphthalene, 2,2'-dimethyl-4,4'-diaminobiphenyl, 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl, 2,7- Diaminopyridine, 4,4'-diaminodiphenyl ether, 1,3-bis(4-aminophenoxy)propane, 2,2-bis[4-(4-aminophenoxy) )Phenyl]propane, 9,9-bis(4-aminophenyl)pyridium, 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane, 2,2-bis (4-Aminophenyl) hexafluoropropane, 4,4'-(p-phenylene diisopropylidene) bisaniline, 4,4'-(m-phenylene diisopropylidene) bisaniline, 1,4-bis(4-aminophenoxy)benzene, 4,4'-bis(4-aminophenoxy)biphenyl, 2,6-diaminopyridine, 3,4-diamino Pyridine, 2,4-diaminopyrimidine, 3,6-diaminoacridine, 3,6-diaminocarbazole, N-methyl-3,6-diaminocarbazole, N-ethyl -3,6-diaminocarbazole, N-phenyl-3,6-diaminocarbazole, N,N'-bis(4-aminophenyl)-benzidine, N,N'-bis (4-aminophenyl)-N,N'-dimethylbenzidine, 1,4-bis-(4-aminophenyl)-piperazine, 1-(4-aminophenyl)-2 ,3-Dihydro-1,3,3-trimethyl-1H-inden-5-amine, 1-(4-aminophenyl)-2,3-dihydro-1,3,3-trimethyl -1H-indene-6-amine, 3,5-diaminobenzoic acid, octadecyloxy-2,5-diaminobenzene, cholesteryloxy-3,5-diaminobenzene, Cholesterenoxy-3,5-diaminobenzene, cholesteryloxy-2,4-diaminobenzene, cholestenoxy-2,4-diaminobenzene, 3,5-diaminobenzene Cholesteryl aminobenzoate, cholesteryl 3,5-diaminobenzoate, lanosteryl 3,5-diaminobenzoate, 3,6-bis(4-amino) Benzyloxy)cholestane, 3,6-bis(4-aminophenoxy)cholestane, 4-(4'-trifluoromethoxybenzyloxy)cyclohexyl-3, 5-diaminobenzoate, 4-(4'-trifluoromethylbenzyloxy)cyclohexyl-3,5-diaminobenzoate, 1,1-bis(4-( (Aminophenyl)methyl)phenyl)-4-butylcyclohexane, 1,1-bis(4-((aminophenyl)methyl)phenyl)-4-heptylcyclohexane , 1,1-bis(4-((aminophenoxy)methyl)phenyl)-4-heptylcyclohexane, 1,1-bis(4-((aminophenyl)methyl) Phenyl)-4-(4-heptylcyclohexyl) Cyclohexane, 2,4-diamino-N,N-diallylaniline, 4-aminobenzylamine, 3-aminobenzylamine, and the following formula (D-1) [Chemical 1 ]

(In formula (D-1), X ^I and X ^II are independently a single bond, -O-, *-COO-, *-OCO- or *-NH-CO- (wherein, those with "*" The bond is bonded to the diamino phenyl group), R ^I and R ^II are each independently an alkanediyl group having 1 to 3 carbons, a is 0 or 1, b is an integer of 0 to 2, and c is 1 to 20 N is 0 or 1, m is 0 or 1; where a and b will not become 0 at the same time, and when X ^I is *-NH-CO-, n is 0) the compound represented by; Examples of the diaminoorganosiloxane include 1,3-bis(3-aminopropyl)-tetramethyldisiloxane, etc.; in addition, Japanese Patent Laid-Open No. 2010-97188 can also be used Diamine described in. Moreover, these diamines can be used individually by 1 type or in combination of 2 or more types.

The divalent group represented by "-X ^I -(R ^I -X ^II ) _n -" in the formula (D-1) is preferably an alkanediyl group having 1 to 3 carbon atoms, *-O-, *- COO-, *-OC ₂ H ₄ -O- or *-NH-CO- (wherein, the bond with "*" is bonded to the diamino phenyl group).

Specific examples of the group "-C _c H _{2c +1} "include, for example, methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n- Nonyl, n-decyl, n-dodecyl, n-tridecyl, n-tetradecyl, n-pentadecyl, n-hexadecyl, n-heptadecyl, n-octadecyl, n Nonadecyl, n-eicosyl, etc. The two amino groups in the diaminophenyl group are preferably located at the 2,4-position or the 3,5-position relative to other groups.

此外，作為二胺可將這些化合物的一種單獨使用或者將兩種以上組合使用。As a specific example of the compound represented by the said formula (D-1), the compound etc. respectively represented by following formula (D-1-1)-formula (D-1-4), for example are mentioned. [化2]

In addition, as the diamine, one kind of these compounds may be used alone or in combination of two or more kinds.

The diamine used when synthesizing the polyamide acid in the present invention preferably contains 30 mol% or more of aromatic diamine relative to all diamines, more preferably contains 50 mol% or more, and particularly preferably contains 80 mol%. Ear% above.

In the case of making a liquid crystal alignment agent for a TN-type, STN-type, or vertical alignment-type liquid crystal display element, in order to impart good liquid crystal alignment, it is preferable to use a diamine having a pretilt component. Examples of such diamines having pretilt components include those having an alkyl group having 4 to 20 carbons, a fluoroalkyl group having 4 to 20 carbons, an alkoxy group having 4 to 20 carbons, and a carbon number of 17 to 20. At least one of the group consisting of a group having a steroid skeleton of 51 and a group in which a plurality of rings are bonded directly or via a linking group is a diamine as a pretilt component. Specifically, for example, dodecyloxy-2,4-diaminobenzene, tetradecyloxy-2,4-diaminobenzene, pentadecyloxy-2,4-diamine Benzene, hexadecyloxy-2,4-diaminobenzene, octadecyloxy-2,4-diaminobenzene, dodecyloxy-2,5-diaminobenzene, fourteen Alkoxy-2,5-diaminobenzene, pentadecyloxy-2,5-diaminobenzene, hexadecyloxy-2,5-diaminobenzene, octadecyloxy-2 ,5-diaminobenzene, cholesteryloxy-3,5-diaminobenzene, cholestenoxy-3,5-diaminobenzene, cholestenoxy-2,4-diamine Benzene, Cholesteryl 3,5-Diaminobenzoate, Cholesteryl 3,5-Diaminobenzoate, Lanosteryl 3,5-Diaminobenzoate, 3, 6-bis(4-aminobenzyloxy)cholestane, 3,6-bis(4-aminophenoxy)cholestane, 4-(4'-trifluoromethoxybenzyl) Oxy)cyclohexyl-3,5-diaminobenzoate, 4-(4'-trifluoromethylbenzyloxy)cyclohexyl-3,5-diaminobenzoate, 1 ,1-Bis(4-((aminophenyl)methyl)phenyl)-4-butylcyclohexane, 1,1-bis(4-((aminophenyl)methyl)phenyl) -4-heptylcyclohexane, 1,1-bis(4-((aminophenoxy)methyl)phenyl)-4-heptylcyclohexane, 1,1-bis(4-(( Aminophenyl)methyl)phenyl)-4-(4-heptylcyclohexyl)cyclohexane, the diamine represented by the above formula (D-1), and the like. In addition, the diamine having a pretilt component may be used alone or in combination of two or more.

The total amount of diamine having a pretilt component is preferably 5 mol% or more, and more preferably 10 mol% or more with respect to all diamines.

When the photo-alignment method is used to impart liquid crystal alignment to the coating film produced using the liquid crystal alignment agent of the present invention, it is preferable to use a part or all of the polymer (A) used in the preparation of the liquid crystal alignment agent of the present invention Set as a polymer having a photo-alignment structure. Here, the so-called photo-alignment structure is a concept including both a photo-alignment group and a decomposition-type photo-alignment portion. Specifically, the photo-alignment structure can be a structure derived from a variety of compounds that exhibit photo-alignment properties through photoisomerization, photodimerization, photolysis, etc., for example: containing azobenzene or its derivatives as the base Azobenzene-containing group of the skeleton, a group having a cinnamic acid structure containing cinnamic acid or its derivative as the basic skeleton, a chalcone-containing group containing chalcone or its derivative as the basic skeleton, Benzophenone or its derivative as the basic skeleton of a benzophenone-containing group, a coumarin or its derivative as a basic skeleton of a coumarin-containing group, or a polyimide or its derivative Polyimide-containing structure as the basic skeleton, etc. (Molecular weight regulator)

When synthesizing polyamide acid, as described above, together with tetracarboxylic dianhydride and diamine, a suitable molecular weight regulator can be used to synthesize a terminal modified polymer. By making the terminal modified polymer, the coating property (printability) of the liquid crystal alignment agent can be further improved without impairing the effect of the present invention.

Examples of the molecular weight modifier include acid monoanhydrides, monoamine compounds, and monoisocyanate compounds. As specific examples of these compounds, acid monoanhydrides include, for example, maleic anhydride, phthalic anhydride, itaconic anhydride, n-decyl succinic anhydride, n-dodecyl succinic anhydride, n-tetradecane Benzyl succinic anhydride, n-hexadecyl succinic anhydride, etc.; monoamine compounds include, for example, aniline, cyclohexylamine, n-butylamine, etc.; monoisocyanate compounds include, for example, phenyl isocyanate, isocyanate Acid naphthyl ester and so on.

The use ratio of the molecular weight modifier is preferably 20 parts by weight or less, and more preferably 10 parts by weight or less with respect to 100 parts by weight of the total of the tetracarboxylic dianhydride and diamine used. ＜Synthesis of polyamide acid＞

The ratio of the tetracarboxylic dianhydride to the diamine used in the synthesis reaction of polyamide acid is preferably 1 equivalent relative to the amine group of the diamine, and the acid anhydride group of the tetracarboxylic dianhydride becomes a ratio of 0.2 to 2 equivalents, More preferably, it is a ratio of 0.3 equivalent to 1.2 equivalent.

The synthesis reaction of polyamide acid is preferably carried out in an organic solvent. The reaction temperature at this time is preferably -20°C to 150°C, more preferably 0°C to 100°C. In addition, the reaction time is preferably 0.1 hour to 24 hours, more preferably 0.5 hour to 12 hours.

Here, the organic solvent includes, for example, aprotic polar solvents, phenolic solvents, alcohols, ketones, esters, ethers, halogenated hydrocarbons, and hydrocarbons.

As specific examples of these organic solvents, aprotic polar solvents include, for example, N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, N-ethyl-2-pyrrolidone, N ,N-dimethylacetamide, N,N-dimethylformamide, dimethyl sulfide, γ-butyrolactone, tetramethylurea, hexamethylphosphatidylamine, etc.; phenolic solvent For example, phenol, m-cresol, xylenol, halogenated phenol, etc. may be mentioned; examples of alcohol include methyl alcohol, ethyl alcohol, isopropyl alcohol, cyclohexanol, ethylene glycol, propylene glycol, 1,4- Butylene glycol, triethylene glycol, ethylene glycol monomethyl ether, etc.; examples of ketones include acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, etc.; examples of esters include ethyl lactate , Butyl lactate, methyl acetate, ethyl acetate, butyl acetate, methyl methoxy propionate, ethyl ethoxy propionate, diethyl oxalate, diethyl malonate, propylene Isoamyl acid, isoamyl isobutyrate, etc.; ethers include, for example, diethyl ether, ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol-n-propyl ether, ethylene glycol-n-butyl ether, and ethylene two Diethylene glycol dimethyl ether, ethylene glycol ethyl ether acetate, diethylene glycol dimethyl ether, diethylene glycol monomethyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol propyl methyl ether, two Ethylene glycol butyl methyl ether, tetrahydrofuran, diisoamyl ether, etc.; halogenated hydrocarbons include, for example, dichloromethane, 1,2-dichloroethane, 1,4-dichlorobutane, trichloroethane, and chlorobenzene , O-dichlorobenzene, etc.; examples of the hydrocarbon include hexane, heptane, octane, benzene, toluene, and xylene.

Among these organic solvents, it is preferable to use one or more selected from the group consisting of aprotic polar solvents and phenolic solvents (hereinafter referred to as organic solvent X), or one or more selected from organic solvents X and selected from A mixture of one or more kinds of alcohols, ketones, esters, ethers, halogenated hydrocarbons, and hydrocarbons (hereinafter referred to as organic solvent Y). In the latter case, the use ratio of the organic solvent Y relative to the total amount of the organic solvent X and the organic solvent Y is preferably 50% by weight or less, more preferably 40% by weight or less, and particularly preferably 30% by weight or less.

The use amount (a) of the organic solvent is preferably such an amount that the total amount (b) of the tetracarboxylic dianhydride and the diamine becomes 0.1% by weight to 50% by weight relative to the total amount (a+b) of the reaction solution.

In the manner as described above, a reaction solution obtained by dissolving polyamide acid is obtained. The reaction solution can be directly supplied to the preparation of the liquid crystal alignment agent, or the polyamide acid contained in the reaction solution can be separated and then supplied to the preparation of the liquid crystal alignment agent, or the separated polyamide acid can also be purified before Provided for the preparation of liquid crystal alignment agents. In the case of dehydrating and ring-closing polyamide to form polyimide, the reaction solution can be directly supplied to the dehydration ring-closing reaction, or the polyamide acid contained in the reaction solution can be separated and then supplied to The dehydration ring-closing reaction, or the separated polyamide acid can be purified and then supplied to the dehydration ring-closing reaction. The isolation and purification of polyamic acid can be carried out according to a known method. ＜Polyimide＞

The polyimide contained in the liquid crystal alignment agent of the present invention can be obtained by dehydrating and ring-closing the polyimide synthesized in the above manner to imidize it.

The polyimide may be a complete amide compound obtained by dehydrating and ring-closing all the amide acid structure of the polyamide acid as its precursor, or it may be a part of the amide acid structure. A partial amide compound in which an amide acid structure and an amide ring structure coexist by dehydration and ring closure. The imidization rate of the polyimide in the present invention is preferably 30% or more, more preferably 40% to 99%, and particularly preferably 50% to 99%. The imidization rate is the sum of the number of amide acid structures and the number of amide ring structures with respect to the polyimide, and the ratio of the number of amide ring structures is expressed as a percentage. Here, a part of the imine ring may be an isoimide ring.

The dehydration ring closure of polyamide acid is preferably carried out by the following method: a method of heating polyamide acid; or dissolving polyamide acid in an organic solvent, and adding a dehydrating agent and a dehydration ring-closing catalyst to the solution, depending on A method of heating is required. Among them, the latter method is preferred.

In the method of adding a dehydrating agent and a dehydration ring-closing catalyst to the polyamide acid solution, the dehydrating agent can be, for example, acid anhydrides such as acetic anhydride, propionic anhydride, and trifluoroacetic anhydride. The amount of the dehydrating agent used is preferably 0.01 mol to 20 mol with respect to 1 mol of the amide acid structure of the polyamide acid. As the dehydration ring-closing catalyst, for example, tertiary amines such as pyridine, collidine, lutidine, and triethylamine can be used. The amount of the dehydration ring-closing catalyst used is preferably 0.01 mol to 10 mol relative to 1 mol of the dehydrating agent used. Examples of the organic solvent used in the dehydration ring-closing reaction include organic solvents exemplified as users in the synthesis of polyamide acid. The reaction temperature of the dehydration ring-closing reaction is preferably 0°C to 180°C, more preferably 10°C to 150°C. The reaction time is preferably 1.0 hour to 120 hours, more preferably 2.0 hours to 30 hours.

In the manner described, a reaction solution containing polyimine is obtained. The reaction solution can be directly supplied to the preparation of the liquid crystal alignment agent, or it can be supplied to the preparation of the liquid crystal alignment agent after removing the dehydrating agent and the dehydration ring-closing catalyst from the reaction solution, or it can be supplied to the liquid crystal alignment agent after the polyimide is separated Preparation of the liquid crystal alignment agent, or the isolated polyimine can be purified and then supplied to the preparation of the liquid crystal alignment agent. These purification operations can be performed according to known methods. ＜Polyurate＞

The polyamide ester contained in the liquid crystal alignment agent of the present invention can be obtained, for example, by the following method: [I] By combining the polyamide acid obtained by the synthesis reaction with a hydroxyl-containing compound, halide, and ring-containing A method of reacting a compound of an oxy group to synthesize; [II] a method of reacting a tetracarboxylic acid diester with a diamine; [III] a method of reacting a tetracarboxylic acid diester dihalide with a diamine.

Here, the hydroxyl group-containing compound used in the method [I] includes, for example, alcohols such as methanol, ethanol, and propanol; and phenols such as phenol and cresol. In addition, the halide includes, for example, bromomethane, bromoethane, bromooctadecane, chloromethane, chlorooctadecane, 1,1,1-trifluoro-2-iodoethane, etc., including Examples of epoxy-based compounds include propylene oxide. The tetracarboxylic acid diester used in the method [II] can be obtained by, for example, ring-opening the tetracarboxylic dianhydride exemplified in the synthesis of the polyamide acid using the alcohols. In addition, the tetracarboxylic acid diester dihalide used in the method [III] can be obtained by reacting the tetracarboxylic acid diester obtained in the above-mentioned manner with an appropriate chlorinating agent such as sulfite chloride. As the diamine used in the method [II] and the method [III], the diamines and the like exemplified in the synthesis of the polyamide acid can be used. In addition, the polyamide ester may have only an amide acid ester structure, or may be a partial ester product in which an amide acid structure and an amide acid ester structure coexist.

The reaction solution containing the polyamide ester can be directly supplied to the preparation of the liquid crystal alignment agent, or it can be supplied to the preparation of the liquid crystal alignment agent after the dehydrating agent and the dehydration ring-closing catalyst are removed from the reaction solution, or the polyamide ester After the separation, it is provided to the preparation of the liquid crystal alignment agent, or the separated polyamide ester can be purified and then provided to the preparation of the liquid crystal alignment agent. These purification operations can be performed according to known methods. ＜Solution viscosity, reduction viscosity and weight average molecular weight＞

The polyamide acid, polyimide and polyamide ester obtained in the above manner preferably have a solution viscosity of 10 mPa·s to 800 mPa·s when they are made into a solution with a concentration of 10% by weight Those are more preferably those having a solution viscosity of 15 mPa·s to 500 mPa·s. In addition, the solution viscosity (mPa·s) of the polymer is a concentration of 10% by weight based on a good solvent for the polymer (such as γ-butyrolactone, N-methyl-2-pyrrolidone, etc.). The polymer solution was measured at 25°C using an E-type rotary viscometer.

The reduced viscosity is not particularly limited as long as it is a range that can form a uniform coating film, but is preferably 0.05 dl/g to 3.0 dl/g, more preferably 0.1 dl/g to 2.5 dl/g, and particularly preferably 0.3 dl/g ~1.5 dl/g.

For the polyamide acid, polyimide, and polyamide ester contained in the liquid crystal alignment agent of the present invention, the weight in terms of polystyrene is measured by Gel Permeation Chromatography (GPC) The average molecular weight is preferably 500 to 100,000, more preferably 1,000 to 50,000. "Solvent"

The liquid crystal alignment agent of the present invention contains at least one selected from the group consisting of diethylene glycol propyl methyl ether and diethylene glycol butyl methyl ether (hereinafter referred to as specific solvent (B)) as a solvent component. By containing such a specific solvent (B) in a liquid crystal alignment agent, it becomes a thing which is especially excellent in printability in an inkjet coating method.

Regarding the specific solvent (B), the propyl group of diethylene glycol propyl methyl ether may be either linear or branched. Specifically, examples include diethylene glycol n-propyl methyl ether, diethylene glycol Alcohol isopropyl methyl ether. Preferably, it is diethylene glycol isopropyl methyl ether. In addition, the butyl moiety of diethylene glycol butyl methyl ether may be either linear or branched. Specifically, examples include diethylene glycol n-butyl methyl ether, diethylene glycol isobutyl methyl ether, and diethylene glycol Dibutyl methyl ether and so on. Preferably, it is diethylene glycol n-butyl methyl ether. In addition, the specific solvent (B) may be used alone or in combination of two or more. (Other solvents)

The liquid crystal alignment agent of the present invention preferably contains other solvents other than the specific solvent (B) as a solvent component. Examples of such other solvents include: a solvent capable of dissolving the polymer (A) contained in the liquid crystal alignment agent of the present invention (hereinafter also referred to as "first solvent"), and a poor solvent for the polymer (A). Organic solvents other than the specific solvent (B), etc.

The first solvent may be a good solvent for the polymer (A), and preferred specific examples thereof include N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N -Pentyl-2-pyrrolidone, 3-methoxy-N,N-dimethylpropanamide, N,N,2-trimethylpropanamide, 3-butoxy-N,N-dimethyl Propyl propionamide, γ-butyrolactone, γ-butyrolactone, N,N-dimethylformamide, N,N-dimethylacetamide, 1,3-dimethyl-2- Imidazolidinone, N-ethyl-2-pyrrolidone, dimethyl sulfoxide, tetramethylurea, hexamethylphosphotriamine, m-cresol, etc. In addition, the first solvent may be used alone or in combination of two or more.

In addition, organic solvents other than the specific solvent (B) that are poor solvents for the polymer (A) include, for example, methyl 2-hydroxyisobutyrate, ethylene glycol monomethyl ether, butyl lactate, Butyl acetate, methyl methoxy propionate, ethyl ethoxy propionate, ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol-n-propyl ether, ethylene glycol-isopropyl ether, ethyl Glycol-n-butyl ether (butyl cellosolve), ethylene glycol dimethyl ether, ethylene glycol ethyl ether acetate, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether ethyl Ester, diethylene glycol monoethyl ether acetate, dipropylene glycol monomethyl ether (DPM), diisobutyl ketone, isoamyl propionate, isoamyl isobutyrate, ethylene carbonate , Propylene carbonate, diacetone alcohol, diethylene glycol diethyl ether, diisoamyl ether, propylene glycol diacetate, etc. The organic solvent can be used alone or in combination of two or more. In addition, hereinafter, a group consisting of an organic solvent other than the specific solvent (B) and the specific solvent (B) as a poor solvent for the polymer (A) is also referred to as a “second solvent”.

From the viewpoint of achieving good printability by the inkjet coating method and suppressing the precipitation of the polymer (A), the content ratio of the specific solvent (B) relative to the total amount of the solvent contained in the liquid crystal alignment agent (in When two or more are used, the total amount is preferably set to 90% by weight or less. It is more preferably 85% by weight or less, particularly preferably 80% by weight or less, and particularly preferably 75% by weight or less. In addition, the lower limit of the content ratio is not particularly limited, but it is preferably 1% by weight or more.

From the viewpoint of suppressing the precipitation of the polymer (A), the content of the first solvent is preferably 5% by weight or more, and more preferably 10% by weight or more with respect to the total amount of solvents contained in the liquid crystal alignment agent , Particularly preferably 20% by weight or more. In addition, from the viewpoint of appropriately obtaining the effect brought about by the addition of the specific solvent (B), the upper limit of the content ratio of the first solvent with respect to the total amount of the solvent contained in the liquid crystal alignment agent It is preferably 95% by weight or less, more preferably 90% by weight or less, and particularly preferably 85% by weight or less.

In the second solvent, the content ratio of organic solvents other than the specific solvent (B) is preferably 80% by weight or less, and more preferably 70% by weight or less, relative to the total amount of solvents contained in the liquid crystal alignment agent. It is particularly preferably 50% by weight or less, and particularly preferably 30% by weight or less.

From the viewpoint of making the coatability to the substrate good, the ratio of the first solvent to the second solvent is preferably set to 0.03 times (weight) or more with respect to the used amount of the first solvent. Preferably, it is 0.05 times (weight) or more. In addition, from the viewpoint of suppressing the precipitation of the polymer, it is preferably 2.5 times (weight) or less, and more preferably 2.0 times (weight) or less. "Other Ingredients"

The liquid crystal alignment agent of the present invention contains the polymer (A) and the solvent as described above, and may contain other components as necessary. Examples of the other components include polymers other than the polymer (A), compounds having at least one epoxy group in the molecule (hereinafter referred to as "epoxy group-containing compounds"), functional silane compounds, etc. . [Other polymers]

The other polymers can be used to improve solution properties or electrical properties. Examples of the other polymers include polyesters, polyamides, polyorganosiloxanes, cellulose derivatives, polyacetals, polystyrene derivatives, poly(styrene-phenyl maleic acid) Amine) derivatives, poly(meth)acrylates, etc. Among these polymers, at least one polymer selected from the group consisting of polyester, polyorganosiloxane, and poly(meth)acrylate is preferable, and polyorganosiloxane is more preferable.

In addition, the other polymer may also use a polymer having a photo-alignment structure. Specifically, it is preferably a polymer having a photo-alignment group, and more preferably a polymer having a cinnamic acid structure introduced as a photo-alignment group. Among them, the polysiloxane having a cinnamic acid structure can be preferably used in terms of easy introduction of the photoalignment group into the polymer.

In addition, the polymer having a photo-alignment group can be synthesized by a conventionally known method. For example, a polysiloxane with a photo-alignment group can be combined with a polysiloxane with an epoxy group in the presence of a catalyst such as a quaternary ammonium salt in an organic solvent such as ether, ester, and ketone. The carboxylic acid of the photoalignment group is synthesized by reacting.

Specifically, polysiloxane can be obtained, for example, by subjecting a hydrolyzable silane compound to hydrolysis and condensation. Silane compounds used in the synthesis of polysiloxanes include, for example, tetramethoxysilane, tetraethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, and 3-mercaptopropyltrimethoxysilane. Silane, 3-aminopropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 2-(3,4-ring (Oxycyclohexyl) ethyl triethoxy silane, 3-(meth) acryloxy propyl trimethoxy silane, vinyl trimethoxy silane, etc., one of these compounds can be used alone or two Use a combination of the above.

The hydrolysis/condensation reaction can be carried out by reacting one or two or more of the above-mentioned silane compounds with water, preferably in the presence of a suitable catalyst and organic solvent. In the hydrolysis/condensation reaction, the use ratio of water is preferably 0.5 mol to 100 mol, and more preferably 1 mol to 30 mol relative to 1 mol of the silane compound (total amount).

Examples of the catalyst used in the hydrolysis and condensation reaction include acids, alkali metal compounds, organic bases, titanium compounds, and zirconium compounds. The amount of the catalyst used varies depending on the type of catalyst, reaction conditions such as temperature, etc., and can be appropriately set. For example, relative to the total amount of the silane compound, it is preferably 0.01 times mol to 3 times mol, more preferably 0.05 times mol to 1 times mole.

Examples of the organic solvent used in the hydrolysis and condensation reaction include hydrocarbons, ketones, esters, ethers, and alcohols. Among these solvents, it is preferable to use a water-insoluble or poorly water-soluble organic solvent. The use ratio of the organic solvent is preferably 10 parts by weight to 10,000 parts by weight, and more preferably 50 parts by weight to 1,000 parts by weight with respect to 100 parts by weight of the total of the silane compounds used in the reaction.

The hydrolysis/condensation reaction is preferably carried out by heating with an oil bath or the like, for example. In the case of the hydrolysis/condensation reaction, the heating temperature is preferably 130°C or lower, and more preferably 40°C to 100°C. The heating time is preferably 0.5 hour to 12 hours, and more preferably 1 hour to 8 hours. During heating, the mixture can be stirred or placed under reflux. In addition, it is preferable to wash the organic solvent layer separated from the reaction liquid with water after the completion of the reaction. In this washing, washing with water containing a small amount of salt (for example, an aqueous solution of ammonium nitrate of about 0.2% by weight, etc.) is preferable in terms of easy washing operation. Washing is performed until the washed water layer becomes neutral, and then the organic solvent layer is dried with a desiccant such as anhydrous calcium sulfate, molecular sieve, etc., if necessary, and then the solvent is removed, thereby obtaining polysiloxane. In addition, by reacting the obtained polysiloxane with a reactive compound (for example, a carboxylic acid having a photoalignment group, etc.), a polysiloxane having a reactive group can be obtained.

The polysiloxane contained in the liquid crystal alignment agent of the present invention preferably has a polystyrene conversion weight average molecular weight (Mw) measured by GPC in the range of 100 to 50,000, and more preferably in the range of 200 to 10,000 . If the weight average molecular weight of the polysiloxane is within the above range, it is easy to handle when manufacturing the liquid crystal alignment film, and the obtained liquid crystal alignment film has sufficient material strength and characteristics.

In the case where the other polymer is added to the liquid crystal alignment agent, the blending ratio of the other polymer is preferably 50 parts by weight or less, more preferably, relative to 100 parts by weight of the total polymer in the liquid crystal alignment agent It is 0.1 weight part-40 weight part, Especially preferably, it is 0.1 weight part-30 weight part.

With regard to the polymer component contained in the liquid crystal alignment agent of the present invention, the following aspects are preferable as examples. (I) An aspect that contains only the polymer (A) as a polymer component. (II) Containing polymer (A) and other polymers as polymer components, and the other polymers are polysiloxanes.

Among these aspects, the aspect (II) described above is preferable in terms of good electrical characteristics.

When polysiloxane is contained in the liquid crystal alignment agent, from the viewpoint of obtaining sufficient printability and electrical characteristics improvement effects, relative to 100 parts by weight of the polymer (A) in total, the polysiloxane The blending ratio of the oxane is preferably 0.5 parts by weight to 90 parts by weight, more preferably 1 part by weight to 85 parts by weight, and particularly preferably 3 parts by weight to 80 parts by weight. [Epoxy-containing compounds]

The epoxy-containing compound can be used to improve the adhesion of the liquid crystal alignment film to the surface of the substrate. Here, the epoxy group-containing compound includes, for example, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, Neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerol diglycidyl ether, trimethylolpropane triglycidyl ether, 2,2-dibromoneopentyl glycol diglycidyl ether Ether, N,N,N',N'-tetraglycidyl-m-xylenediamine, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, N,N, N',N'-tetraglycidyl-4,4'-diaminodiphenylmethane, N,N-diglycidyl-benzylamine, N,N-diglycidyl-aminomethyl Cyclohexane, N,N-diglycidyl-cyclohexylamine, etc.

In the case of adding these epoxy compounds to the liquid crystal alignment agent, the blending ratio of the epoxy compound is preferably 40 parts by weight or less, more preferably, relative to 100 parts by weight of the total polymer contained in the liquid crystal alignment agent It is 0.1 parts by weight to 30 parts by weight. [Functional Silane Compound]

The functional silane compound can be used for the purpose of improving the printability of the liquid crystal alignment agent. Examples of such functional silane compounds include: 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 2-aminopropyltrimethoxysilane, 2-aminopropyl Triethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxy Silane, 3-ureidopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, N-ethoxycarbonyl-3-aminopropyltrimethoxysilane, N-triethoxy Silylpropyltriethylenetriamine, 10-trimethoxysilyl-1,4,7-triazadecane, 9-trimethoxysilyl-3,6-diazanonylacetic acid Ester, 9-trimethoxysilyl-3,6-diazanonanoate methyl ester, N-benzyl-3-aminopropyl trimethoxysilane, N-phenyl-3-aminopropyl trimethyl Oxysilane, glycidoxymethyltrimethoxysilane, 2-glycidoxyethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, etc.

When these functional silane compounds are added to the liquid crystal alignment agent, the blending ratio of the functional silane compound is preferably 2 parts by weight or less, more preferably 0.02 parts by weight to 100 parts by weight in total of the polymer. 0.2 parts by weight.

The solid content concentration in the liquid crystal alignment agent of the present invention (the ratio of the total weight of the components other than the solvent of the liquid crystal alignment agent to the total weight of the liquid crystal alignment agent) can be appropriately selected in consideration of viscosity, volatility, etc., preferably It is in the range of 1% by weight to 10% by weight. That is, the liquid crystal alignment agent of the present invention is applied to the surface of the substrate in the manner described below, preferably by heating, to form a coating film as a liquid crystal alignment film or a coating film as a liquid crystal alignment film. At this time, when the solid content concentration is less than 1% by weight, the film thickness of the coating film becomes too small, and it is difficult to obtain a good liquid crystal alignment film. On the other hand, when the solid content concentration exceeds 10% by weight, the film thickness of the coating film becomes too large and it is difficult to obtain a good liquid crystal alignment film. In addition, the viscosity of the liquid crystal alignment agent increases and coating characteristics deteriorate.

The particularly preferable range of the solid content concentration varies depending on the method used when applying the liquid crystal alignment agent on the substrate. For example, when the spin coating method is used, the solid content concentration is particularly preferably in the range of 1.5% by weight to 4.5% by weight. In the case of using the offset printing method, it is particularly preferable to set the solid content concentration to the range of 3% by weight to 9% by weight, thereby setting the solution viscosity to the range of 12 mPa·s to 50 mPa·s. In the case of using the inkjet printing method, it is particularly preferable to set the solid content concentration to the range of 1% by weight to 8% by weight, thereby setting the solution viscosity to the range of 3 mPa·s to 20 mPa·s. The temperature when preparing the liquid crystal alignment agent of the present invention is preferably 10°C to 50°C, more preferably 20°C to 30°C. <Liquid crystal alignment film and liquid crystal display element>

The liquid crystal alignment film of the present invention can be formed using the liquid crystal alignment agent prepared in the manner described above. In addition, the liquid crystal display element of the present invention includes a liquid crystal alignment film formed using the liquid crystal alignment agent of the present invention. The driving mode of the liquid crystal display element to which the present invention is applied is not particularly limited, and can be applied to various driving modes such as TN type, STN type, IPS type, FFS type, VA type, and MVA type. Hereinafter, the manufacturing method of the liquid crystal display element of the present invention will be described, and in the description, the manufacturing method of the liquid crystal alignment film of the present invention will be described.

The liquid crystal display element of the present invention can be manufactured by the following steps (1) to (3), for example. Step (1) Use different substrates according to the required drive mode. Steps (2) and (3) are shared in each drive mode. [Step (1): Formation of coating film]

First, the liquid crystal alignment agent of the present invention is coated on the substrate, and then the coated surface is heated, thereby forming a coating film on the substrate.

(1-1) In the case of manufacturing a TN type, STN type or VA type liquid crystal display element, two substrates provided with a patterned transparent conductive film are used as a pair, and each transparent conductive film on the substrate On the forming surface, it is preferable to apply the liquid crystal alignment agent of the present invention separately by an offset printing method, a spin coating method, a roll coater method, or an inkjet printing method. The liquid crystal alignment agent of the present invention has an advantage that it can exhibit particularly good coating properties (printability) when the inkjet printing method is adopted as the coating method.

Here, the substrate can be, for example, glass such as float glass and soda glass; including polyethylene terephthalate, polybutylene terephthalate, polyether alkene, polycarbonate, poly(alicyclic olefin) ) And other plastic transparent substrates. The transparent conductive film provided on one side of the substrate can use NESA film containing tin oxide (SnO ₂ ) (registered trademark of PPG Corporation in the United States), or indium oxide-tin oxide (In ₂ O ₃ -SnO ₂ ). Indium Tin Oxide (ITO) film, etc. In order to obtain a patterned transparent conductive film, for example, the following methods can be used: a method of forming a pattern by photoetching after forming a transparent conductive film without a pattern; a method of using a mask with a desired pattern when forming a transparent conductive film, etc. . When applying the liquid crystal alignment agent, in order to improve the adhesion between the substrate surface and the transparent conductive film and the coating film, the surface of the substrate surface where the coating film should be formed can also be pre-coated with functional silane compounds, functional titanium compounds, etc. The pretreatment.

After the liquid crystal alignment agent is applied, for the purpose of preventing sagging of the applied alignment agent, it is preferable to perform preheating (prebaking). The pre-baking temperature is preferably 30°C to 200°C, more preferably 40°C to 150°C, and particularly preferably 40°C to 100°C. The pre-baking time is preferably 0.25 minutes to 10 minutes, more preferably 0.5 minutes to 5 minutes. Then, for the purpose of completely removing the solvent and thermally imidizing the amide structure existing in the polymer as necessary, a calcination (post-baking) step is performed. The calcination (post-baking) temperature is preferably 80°C to 300°C, more preferably 120°C to 250°C. The post-baking time is preferably 5 minutes to 200 minutes, more preferably 10 minutes to 100 minutes. The film thickness of the film formed in this manner is preferably 0.001 μm to 1 μm, and more preferably 0.005 μm to 0.5 μm.

(1-2) In the case of manufacturing IPS-type or FFS-type liquid crystal display elements, the electrode formation surface of the substrate is provided with electrodes including a transparent conductive film or a metal film patterned into a comb tooth shape, and the electrode is not provided. On one side of the opposed substrate, the liquid crystal alignment agent of the present invention is respectively coated, and then each coated surface is heated, thereby forming a coating film. At this time, the material of the substrate and the transparent conductive film, the coating method, the heating conditions after coating, the patterning method of the transparent conductive film or the metal film, the pretreatment of the substrate, and the preferred film thickness of the formed coating film are as described above. (1-1) Same. As the metal film, for example, a film containing metal such as chromium can be used.

In any of the above (1-1) and (1-2), after applying a liquid crystal alignment agent on the substrate, the organic solvent is removed to form a coating film that becomes an alignment film. In this case, the polymer contained in the liquid crystal alignment agent of the present invention is polyamide acid, or polyamide acid ester, or an amide polymer having an amide ring structure and an amide acid structure. In the case of the coating film, it is also possible to perform a dehydration ring-closure reaction by further heating after the coating film is formed, thereby forming a coating film that is further imidized. [Step (I-2): Alignment ability grant processing]

In the case of manufacturing a TN-type, STN-type, IPS-type, or FFS-type liquid crystal display element, a process of imparting liquid crystal alignment ability to the coating film formed in the step (I-1) is performed. Thereby, the alignment ability of the liquid crystal molecules is imparted to the coating film to become a liquid crystal alignment film. The treatment for imparting liquid crystal alignment ability includes rubbing treatment and photo-alignment treatment. The rubbing treatment uses a roller wound with a cloth containing fibers such as nylon, rayon, cotton, etc., to wipe the coating film in a certain direction; The alignment treatment irradiates the coating film with polarized or non-polarized radiation. On the other hand, in the case of manufacturing a VA-type liquid crystal display element, the coating film formed in the step (I-1) can be directly used as a liquid crystal alignment film, but the coating film may be subjected to an alignment ability imparting treatment.

In the photo-alignment process, the radiation irradiated to the coating film can use, for example, ultraviolet rays and visible rays including light with a wavelength of 150 nm to 800 nm. When the radiation is polarized light, it may be linearly polarized light or partially polarized light. In addition, when the radiation used is linearly polarized light or partially polarized light, the substrate surface may be irradiated from a vertical direction, may be irradiated from an oblique direction, or these irradiations may be combined. In the case of irradiating non-polarized radiation, the direction of irradiation is an oblique direction.

As the light source used, for example, a low-pressure mercury lamp, a high-pressure mercury lamp, a deuterium lamp, a metal halide lamp, an argon resonance lamp, a xenon lamp, an excimer laser, etc. can be used. Ultraviolet rays in a preferred wavelength range can be obtained by a method of using a light source in combination with, for example, an optical filter and a diffraction grating. The radiation dose is preferably 100 J/m ² to 50,000 J/m ² , and more preferably 300 J/m ² to 20,000 J/m ² . In addition, in order to improve the reactivity, the coating film may be irradiated with light while heating the coating film. The temperature during heating is usually 30°C to 250°C, preferably 40°C to 200°C, and more preferably 50°C to 150°C.

In addition, the liquid crystal alignment film after the rubbing treatment can be further subjected to the following treatment to make the liquid crystal alignment film have different liquid crystal alignment capabilities in each region: by irradiating a part of the liquid crystal alignment film with ultraviolet rays, a part of the liquid crystal alignment film The process of changing the pretilt angle of the region; or the process of removing the resist film after forming a resist film on a part of the surface of the liquid crystal alignment film and then performing a rubbing treatment in a direction different from the previous rubbing treatment. In this case, the visual field characteristics of the obtained liquid crystal display element can be improved. The liquid crystal alignment film suitable for VA-type liquid crystal display elements can also be suitably used for polymer sustained alignment (PSA)-type liquid crystal display elements. [Step (3): Construction of the liquid crystal cell]

Two substrates on which the liquid crystal alignment film is formed in the manner described above are prepared, and liquid crystals are arranged between the two substrates arranged opposite to each other, thereby manufacturing a liquid crystal cell. To manufacture the liquid crystal cell, for example, the following two methods can be cited.

The first method is a previously known method. First, the two substrates are arranged to face each other through a gap (cell gap) in such a way that the respective liquid crystal alignment films are opposed to each other, and the peripheral parts of the two substrates are bonded using a sealant. After injecting and filling the liquid crystal into the cell gap, the injection hole is sealed, so that a liquid crystal cell can be manufactured. In addition, the second method is a method called One Drop Fill (ODF) method. On a predetermined part of one of the two substrates on which the liquid crystal alignment film is formed, for example, a UV-curable sealing material is coated, and then liquid crystal is dropped on a predetermined number of positions on the liquid crystal alignment film surface, and then the liquid crystal The alignment film is bonded to another substrate in an opposing manner, and the liquid crystal is spread on the entire surface of the substrate, and then ultraviolet light is irradiated to the entire surface of the substrate to harden the sealant, thereby manufacturing a liquid crystal cell. In the case of using either method, it is ideal to heat the liquid crystal cell manufactured in the above manner until the temperature at which the liquid crystal used obtains the isotropic phase, and then slowly cool to room temperature, thereby eliminating the liquid crystal Flow alignment during filling.

As the sealing agent, for example, an epoxy resin containing a curing agent and alumina balls as spacers can be used.

The liquid crystals include nematic liquid crystals and smectic liquid crystals. Among them, nematic liquid crystals are preferable. For example, Schiff base liquid crystals, azoxy liquid crystals, biphenyl liquid crystals, and benzene can be used. Cyclohexane-based liquid crystal, ester-based liquid crystal, terphenyl-based liquid crystal, biphenylcyclohexane-based liquid crystal, pyrimidine-based liquid crystal, dioxane-based liquid crystal, bicyclooctane-based liquid crystal, cubane-based liquid crystal, etc. In addition, the following substances can also be added to these liquid crystals for use: for example, cholesteryl chloride, cholesteryl nonanoate, cholesteryl carbonate and other cholesteric liquid crystals. ); chiral agents sold under the trade names "C-15" and "CB-15" (manufactured by Merck); p-decyloxybenzylidene-p-amino-2-methylbutyl Ferroelectric liquid crystals such as cinnamate.

Then, the liquid crystal display element of the present invention can be obtained by bonding a polarizing plate to the outer surface of the liquid crystal cell. Examples of the polarizing plate bonded to the outer surface of the liquid crystal cell include: a polarizing plate formed by sandwiching a polarizing film called "H film" with a cellulose acetate protective film or a polarizing plate containing the H film itself. "H film" is a film formed by absorbing iodine while extending and aligning polyvinyl alcohol. In addition, when the coating film is rubbed, the two substrates are arranged so that the rubbing direction in each coating film forms a predetermined angle with each other, for example, orthogonal or antiparallel.

The liquid crystal display element of the present invention can be effectively applied to various devices, such as: desktop computers, watches, desk clocks, mobile phones, counter display panels, word processors, personal computers, LCD TVs, portable game consoles, car navigation Display devices for systems, camcorders, personal digital assistants (PDAs), digital cameras, smart phones, various monitors, etc. [Example]

Hereinafter, the present invention will be further described in detail through examples, but the present invention is not limited to these examples. [Weight average molecular weight of polymer]

The weight average molecular weight Mw is a polystyrene conversion value measured by gel permeation chromatography under the following conditions. Column: manufactured by Tosoh (Stock), TSKgelGRCXLII Solvent: Tetrahydrofuran Temperature: 40℃ Pressure: 68 kgf/cm ² [Solution viscosity of polymer solution]

The solution viscosity [mPa·s] of the polymer solution is a solution prepared with a polymer concentration of 10% by weight using a predetermined solvent, and measured at 25° C. with an E-type rotary viscometer.

In addition, the required amounts of raw material compounds and polymers used in the following examples are ensured by repeating the synthesis of the raw material compounds and polymers on the synthesis scale shown in the following synthesis examples as necessary. [Synthesis of Polyamide Acid] [Synthesis Example 1]

Combine 112 g (0.50 mol) of 2,3,5-tricarboxycyclopentylacetic dianhydride as tetracarboxylic dianhydride and 157 g (0.50 mol) of 1,3,3a,4,5,9b -Hexahydro-8-methyl-5-(tetrahydro-2,5-dioxo-3-furyl)-naphtho[1,2-c]-furan-1,3-dione, and as Diamine compound 95 g (0.88 mol) of p-phenylenediamine, 32 g (0.10 mol) of 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl, 6.4 g (0.010 mol) of 3,6-bis(4-aminobenzyloxy)cholestane and 4.0 g (0.015 mol) of octadecyloxy-2,5-diaminobenzene, It was dissolved in 960 g of N-methyl-2-pyrrolidone and reacted at 60°C for 9 hours. The obtained polyamide acid solution (PA-1) was aliquoted in a small amount, and N-methyl-2-pyrrolidone was added to prepare a solution with a concentration of 10% by weight. The measured viscosity of the solution was 58 mPa·s. [Synthesis of polyorganosiloxane having epoxy group] [Synthesis Example 2]

In a reaction vessel equipped with a stirrer, thermometer, dropping funnel and reflux cooling tube, add 100.0 g of 2-(3,4-epoxycyclohexyl) ethyl trimethoxysilane (2-(3,4-epoxycyclohexyl) ) ethyl trimethoxy silane, ECETS), 500 g of methyl isobutyl ketone and 10.0 g of triethylamine, mixed at room temperature. Then, 100 g of deionized water was dropped into the dropping funnel for 30 minutes, and the reaction was carried out at 80°C for 6 hours while mixing under reflux. After the reaction, the organic layer was taken out and washed with a 0.2% by weight aqueous ammonium nitrate solution until the washed water became neutral, and then the solvent and water were distilled off under reduced pressure to obtain a viscous transparent liquid with a ring Oxy-based polyorganosiloxane. [Synthesis of photoalignment polyorganosiloxane] [Synthesis Example 3]

[合成例4]In a 100 mL three-necked flask, 9.3 g of the epoxy-containing polyorganosiloxane obtained in Synthesis Example 2, 26 g of methyl isobutyl ketone, and 3 g of the following cinnamic acid derivative were added (K-1) and 0.10 g of the trade name "UCAT 18X" (quaternary amine salt manufactured by San-Apro Co., Ltd.), stirred at 80°C for 12 hours. After the reaction, reprecipitate with methanol and dissolve the precipitate in ethyl acetate to obtain a solution. After washing the solution three times with water, the solvent was distilled off to obtain 6.3 g of photo-aligned polyorganic in the form of white powder. Siloxane compound (S-1). The weight average molecular weight Mw of the photo-alignable polyorganosiloxane compound (S-1) is 3,500. [化3]

[Synthesis Example 4]

(Synthesis of Compound (K-2)) [Chemical 4]

Add 4.63 g of compound (A-1), 50 mL of thionyl chloride and 0.05 mL of N,N-dimethylformamide to a 100 mL eggplant-shaped flask equipped with a reflux tube and nitrogen inlet tube, and reflux 1 hour. After the reaction was completed, it was dried by concentration under reduced pressure, and then 75 mL of tetrahydrofuran (as (A-2) liquid) was added. On the other hand, add 2.62 g of 4-hydroxycinnamic acid, 4.41 g of potassium carbonate, 38 mL of water, 19 mL of tetrahydrofuran, and 0.15 g of tetrabutyl bromide to a 100 mL three-necked flask equipped with a thermometer and nitrogen introduction tube. Base ammonium, cooled in an ice bath to below 5°C. Then, after adding the just prepared (A-2 liquid) over 30 minutes, it returned to room temperature and stirred for 4 hours. After the reaction, 100 mL of ethyl acetate and 200 mL of 1N hydrochloric acid water were added for washing, and then 100 mL of water was used for 3 separate washing. Next, after drying the organic layer with magnesium sulfate, it filtered and concentrated under reduced pressure, and the precipitated white crystal was filtered and dried, and 1.8 g of compound (K-2) was obtained. [Synthesis Example 5]

(Synthesis of Compound (K-3)) [Chemical 5]

Into a 300 mL three-necked flask containing a stir bar, 5.09 g of lithium chloride and 1.64 g of zinc chloride were added, and nitrogen replacement was performed. Add 120 mL of ethylene magnesium chloride-tetrahydrofuran 1 mol/L solution, stir at room temperature for 1 hour, then cool to 0°C, add 12.6 g of cyclooctanone dropwise to it, and continue at room temperature for 15 hours Reaction (as (A-5) solution). Then, while performing an ice bath, a saturated aqueous ammonium chloride solution was added dropwise to the solution (A-5), and 300 mL of ethyl acetate was added. After the organic layer was separated and washed with 300 mL of water three times, the organic layer was dried with magnesium sulfate. Then, by concentrating with a rotary evaporator, the solvent was distilled off, and the residue was distilled to obtain 11.7 g of compound (A-3).

In a 300 mL three-necked flask with a stir bar, add 10.9 g of compound (A-3), and ice-bath to 0°C. 134 mL of n-butyllithium-hexane 1.6 mol/L solution was added dropwise, after stirring at 0°C for 20 minutes, 13.9 g of 4-(chlorocarbonyl)benzoic acid was dissolved in 30 mL of tetrahydrofuran. The methyl ester solution was stirred at 0°C for 2 hours. 5 mL of water was added dropwise, and 200 mL of ethyl acetate was added. After the organic layer was separated and washed with 300 mL of water three times, the organic layer was dried with magnesium sulfate. Then, 13.4 g of the compound (A-4) was obtained by concentration using a rotary evaporator.

In a 100 mL three-necked flask with a stir bar, add 9.55 g of compound (A-4), 30 g of methanol, 10 g of water, and 2.52 g of lithium hydroxide monohydrate, and stir at room temperature for 1 hour Then, 50 mL of ethyl acetate was added to the reaction solution. The organic layer was separated and washed with 10 mL of dilute hydrochloric acid once, and was separated and washed with 50 mL of water three times, and then the organic layer was dried with magnesium sulfate. Then, it was concentrated by a rotary evaporator and gradually concentrated until the content became 20 g, and the white solid precipitated in the middle was recovered by filtration. The white solid was vacuum-dried to obtain 5.5 g of compound (K-3). [Synthesis Example 6]

In a 100 mL three-necked flask, 9.3 g of the epoxy-containing polyorganosiloxane obtained in Synthesis Example 2, 26 g of methyl isobutyl ketone, and 5.8 g of Synthesis Example 4 were added The obtained compound (K-2) and 0.10 g of the trade name "UCAT 18X" (quaternary amine salt manufactured by San-Apro Co., Ltd.) were stirred at 80°C for 12 hours. After the reaction, reprecipitate with methanol and dissolve the precipitate in ethyl acetate to obtain a solution. After washing the solution with water three times, the solvent was distilled off to obtain 9.1 g of optical alignment in the form of white powder Polyorganosiloxane compound (S-2). The weight average molecular weight Mw of the photo-alignable polyorganosiloxane compound (S-2) is 3,600. [Synthesis Example 7]

In a 100 mL three-necked flask, 9.3 g of the epoxy-containing polyorganosiloxane obtained in Synthesis Example 2, 26 g of methyl isobutyl ketone, and 5.8 g of Synthesis Example 4 were added (K-2) obtained, 1.8 g of (K-3) obtained in Synthesis Example 5, and 0.10 g of the trade name "UCAT 18X" (quaternary amine manufactured by San-Apro (Stock) Salt) and stirred at 80°C for 12 hours. After the reaction, reprecipitate with methanol and dissolve the precipitate in ethyl acetate to obtain a solution. After washing the solution with water three times, the solvent was distilled off to obtain 6.3 g of photo-alignment in the form of white powder Polyorganosiloxane compound (S-3). The weight average molecular weight Mw of the photo-alignable polyorganosiloxane compound (S-3) is 3,500. [Example 1]

In the polyamide acid solution (PA-1) obtained in the synthesis example 1, 8 parts by weight of the photo-aligned polyorganosiloxane obtained in the synthesis example 3 were added to 100 parts by weight of the polyamide acid (S-1), and then add N-methyl-2-pyrrolidone and diethylene glycol isopropyl methyl ether to make a solvent composition of N-methyl-2-pyrrolidone: diethylene glycol isopropyl methyl ether = 30: 70 (weight ratio), a solution with a solid content of 3.0%. The solution was filtered with a filter with a pore size of 0.2 μm, and then provided for the following evaluation. <Evaluation of inkjet coating properties>

As a substrate coated with a liquid crystal alignment agent, a glass substrate with a transparent electrode containing ITO was heated on a hot plate at 200°C for 1 minute, followed by ultraviolet/ozone washing, so that the contact angle of water on the transparent electrode surface was 10° Following the substrate shortly after.

Use an inkjet coater (manufactured by Shibaura Mechatronics (stock)) to coat the prepared liquid crystal alignment agent (filtered liquid crystal alignment agent) on the transparent electrode surface of the glass substrate with transparent electrodes . The coating conditions at this time were as follows: two reciprocating coatings (4 times in total) at 2,500 times/(nozzle·min) and a discharge amount of 250 mg/10 seconds. After being allowed to stand for 1 minute after coating, heating was performed to form a coating film having an average film thickness of 0.1 μm. The obtained coating film was observed with the naked eye under the irradiation of an interference fringe measuring lamp (sodium lamp), and the evaluation of unevenness and depression was performed. The heating temperature was set to 50°C, 60°C, and 80°C, and the case where neither unevenness nor depression was found at any temperature was regarded as inkjet coatability "good A (◎)", and it was found at one of the heating temperatures Unevenness and/or dents are regarded as "good B (○)", and the situation where unevenness and/or dents are found at two heating temperatures is regarded as "possible (△)", and unevenness will be found at all heating temperatures And/or dents are regarded as "bad (×)". The inkjet coatability of the liquid crystal alignment agent of this example was "good B (○)". ＜Manufacture of liquid crystal cell＞

The liquid crystal cell used for evaluation of liquid crystal orientation and voltage retention was manufactured in the following manner. In addition, in the manufacture of the liquid crystal cell, the spin coating method is used to apply the liquid crystal alignment agent. The reason for this is that it can be compared with a comparative example described later, which has poor inkjet coating properties.

Using the spin coating method, the prepared liquid crystal alignment agent (filtered liquid crystal alignment agent) was coated on the transparent electrode surface of a glass substrate with a transparent electrode containing an ITO film, and pre-baked on a hot plate at 80°C For 1 minute, then post-baking on a hot plate at 200°C for 10 minutes, thereby forming a coating film with an average film thickness of 0.1 μm. Repeat the same operation to produce a pair (two) of substrates with a coating film on the transparent conductive film. Then, using Hg-Xe lamp and Glan-Taylor prism on the substrate surface on the side with the coating film, irradiate 1,000 J/m ² of polarized ultraviolet rays from the vertical direction of the substrate surface to obtain a film thickness It is a pair of substrates of 0.1 μm liquid crystal alignment film.

After coating each outer edge of the pair of substrates with a liquid crystal alignment film with an epoxy resin adhesive added with an alumina ball with a diameter of 5.5 μm, the liquid crystal alignment film faces are overlapped and pressed together to make the adhesive The adhesive hardens. Then, a nematic liquid crystal (MLC-6601, manufactured by Merck) is filled between the pair of substrates from the liquid crystal injection port, and the liquid crystal injection port is sealed with an acrylic light-curing adhesive, thereby manufacturing a liquid crystal cell . ＜Evaluation of voltage holding rate＞

To the obtained liquid crystal cell, after applying a voltage of 5 V with an application time of 60 microseconds and a span of 167 milliseconds, the voltage retention rate after 167 milliseconds from the release of the application was measured. The measuring device used VHR-1 manufactured by Toyo Technica (stock). The case where the value is 95% or more is evaluated as the voltage retention rate "good A (◎)", the case where the value is less than 95% and 93% or more is evaluated as the voltage retention rate "good B (○)", and the voltage retention rate is less than 93% The case was evaluated as the voltage retention rate "acceptable (△)", and the case that could not be evaluated was evaluated as the voltage retention rate "bad (×)". As a result, the voltage retention rate of the liquid crystal cell of this example was "good (◎)" . [Example 2 to Example 11 and Comparative Example 1 to Comparative Example 4, and Comparative Example 6]

A liquid crystal alignment agent was prepared in the same manner as in Example 1, except that the types and amounts of polymers and solvents shown in Table 1 below were used in Example 1, and various evaluations were performed. The evaluation results are shown in Table 1 below. [Example 12 and Comparative Example 5]

Except for the aspects of using the types and amounts of polymers and solvents shown in Table 1 below in the above-mentioned Example 1, and the aspect of performing rubbing treatment instead of the photo-alignment treatment when manufacturing the liquid crystal cell, it is used with The liquid crystal alignment agent was prepared in the same manner as in Example 1, and various evaluations were performed. Using a rubbing machine with a roll wound with nylon cloth, the rubbing treatment was performed at a roll rotation speed of 1,000 rpm, a table moving speed of 25 mm/sec, and a wool press-in length of 0.4 mm. The evaluation results are shown in Table 1 below.

表1中，化合物的略稱分別為以下含義。 IPDM：二乙二醇異丙基甲醚 BDM：二乙二醇正丁基甲醚 NMP：N-甲基-2-吡咯烷酮 BC：丁基溶纖劑 DPM：二丙二醇單甲醚 DEDG：二乙二醇二乙醚[Table 1]

In Table 1, the abbreviations of the compounds have the following meanings, respectively. IPDM: Diethylene glycol isopropyl methyl ether BDM: Diethylene glycol n-butyl methyl ether NMP: N-methyl-2-pyrrolidone BC: Butyl cellosolve DPM: Dipropylene glycol monomethyl ether DEDG: Diethylene glycol diethyl ether

As shown in Table 1, the printability and voltage retention rate by the inkjet coating method in any of Examples 1 to 12 were evaluated as "good A (◎)" or "good B (○)". In contrast, the comparative example is inferior to the examples in at least one of printability and voltage retention by the inkjet coating method.

no

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Claims (3)

A liquid crystal alignment agent comprising at least one polymer (A) selected from the group consisting of polyamide acid, polyimide and polyamide ester and a solvent. The liquid crystal alignment agent is characterized by: The solvent contains at least one selected from the group consisting of diethylene glycol propyl methyl ether and diethylene glycol butyl methyl ether, and the liquid crystal alignment agent further contains a photo-alignment polyorganosiloxane compound relative to The total amount of the polymer (A) is 100 parts by weight, and the content of the photo-alignable polyorganosiloxane compound is 0.5 parts by weight to 90 parts by weight. A liquid crystal alignment film, which is formed using the liquid crystal alignment agent described in the first item of the scope of patent application. A liquid crystal display element comprising the liquid crystal alignment film as described in item 2 of the scope of patent application.