CN102276835A - Treated polymers for liquid crystal alignment agents, their preparation and use - Google Patents

Abstract

A treated polymer for a liquid crystal aligning agent, a preparation method and uses thereof. The preparation method comprises the following steps: subjecting a tetracarboxylic dianhydride compound and a diamine compound to a polymerization reaction to obtain an untreated polymer; preparing a coprecipitation solvent for an untreated polymer, the coprecipitation solvent containing a poor solvent as a main component and a good solvent as a sub-component; and treating the untreated polymer with the coprecipitation solvent to remove at least a portion of the polymer component having a molecular weight of not more than 3,000 from the untreated polymer to obtain the treated polymer. The invention also provides a treated polymer for the liquid crystal alignment agent, the liquid crystal alignment agent containing the treated polymer, a liquid crystal alignment film formed by the liquid crystal alignment agent and a liquid crystal display element containing the liquid crystal alignment film. The treated polymer for the liquid crystal alignment agent of the invention utilizes the coprecipitation solvent to treat the untreated polymer, and the alignment agent, the alignment film and the display element prepared by the alignment agent can really have shorter residual image eliminating time when being used by adjusting the characteristics of the liquid crystal alignment agent prepared subsequently, thereby achieving the aim of the invention.

Description

Treated polymer for liquid crystal alignment agent, its preparation method and use

technical field

The present invention relates to a polymer, its preparation method and its use, in particular to a treated polymer for liquid crystal alignment agent, its preparation method and its use. The present invention further relates to a liquid crystal alignment agent containing the treated polymer, a liquid crystal alignment film formed from the liquid crystal alignment agent, and a liquid crystal display element containing the liquid crystal alignment film.

Background technique

Liquid crystal display elements were mainly used in the screens of notebook computers or desktop personal computers in the early days, and were also used in various liquid crystal display devices such as camera viewfinders and projection displays, and have been widely used in recent years. for making televisions.

The industry generally uses nematic liquid crystal display elements as the mainstream. Among the nematic liquid crystal display elements, the types that are actually used are as follows: (1) The alignment direction of the liquid crystal on one side of the substrate is different from that on the other side. Twisted Nematic (TN) type liquid crystal display elements in which the liquid crystal alignment direction of the substrate is at an angle of 90 degrees; Twisted nematic (Super Twisted Nematic; STN) type liquid crystal display element; and (3) Thin Film Transistor (Thin Film Transistor; TFT) type liquid crystal display element.

Based on the continuous improvement of the quality of related technological products and the user's requirements for the quality of liquid crystal display devices, liquid crystal display elements must be continuously improved accordingly. In the component materials that make up the liquid crystal display element, the liquid crystal alignment film is an important part related to the display quality of the liquid crystal display element, so with the high quality of the liquid crystal display element, the role of the liquid crystal alignment film is becoming more and more Important; therefore, in order to improve the display quality of liquid crystal display elements, such as image sticking, there is still a need to continuously improve the existing liquid crystal alignment film.

The liquid crystal alignment film is prepared from a liquid crystal alignment agent, and the existing method of preparing the liquid crystal alignment film is mainly to dissolve polyamic acid or soluble polyimide in an organic solvent to form a solution, and then the solution is Coating on the substrate, and forming a film by heating or other methods, and then forming a polyamic acid or polyimide alignment film.

The above-mentioned afterimage problem is mainly caused by residual direct current (DC). When the residual amount of direct current (DC) is large, after the voltage is applied, even after the voltage is turned off, the image that should have disappeared will still remain on the display device. That is, a so-called "afterimage" is produced. Aiming at this problem, most of the solutions currently proposed are to improve the afterimage problem by changing the composition and dosage of the alignment agent.

Japanese Patent Application Laid-Open No. 11-193345 discloses a polyimide resin (polyimide resin) formed by two or more polyamic acids having different physical properties and used to prepare liquid crystal alignment films.

WO 00/61684 and its corresponding Chinese Taiwan Patent Application No. 483908 are a kind of varnish composition, and the varnish composition is made of specific structure polyamic acid and polyamide, or specific structure polyamide and soluble polyimide A polymer composed of amines.

WO 2007/078153 discloses a composition for liquid crystal alignment, comprising an oligoimide (oligoimide) or an oligoamic acid (oligoamic acid), at least One end contains a heat-curable or light-curable functional group. This published application mentions that in the optical resolution process, the polyimide used for liquid crystal alignment will be selectively decomposed by light and inevitably produce decomposition by-products. This decomposition by-product can cause serious problems in alignment stability and long-term reliability (especially image sticking).

US 2004/0031950 discloses a liquid crystal alignment agent. This published application specifically mentions the use of poor solvents to purify polyamic acid used in the preparation of liquid crystal alignment agents.

However, the above-mentioned prior art still cannot completely solve the problem of long image sticking elimination time, therefore, there is still a need to develop a liquid crystal alignment agent that can effectively shorten the image sticking elimination time.

Contents of the invention

The object of the present invention is to provide a liquid crystal alignment agent that can effectively shorten the time for eliminating image sticking.

Therefore, according to the first embodiment of the present invention, there is provided a method for preparing a treated polymer used in a liquid crystal alignment agent, which includes the following steps: polymerizing a tetracarboxylic dianhydride compound and a diamine compound to Obtaining an untreated polymer; preparing a co-precipitation solvent for the untreated polymer, the co-precipitation solvent containing a poor solvent as a main component and a good solvent as a secondary component, the poor solvent is selected from ketones, ethers or a combination of these; and treating the untreated polymer with the co-precipitation solvent to remove at least a portion of the polymer component having a molecular weight not greater than 3,000 from the untreated polymer to obtain the treated polymer things.

According to the method for preparing a treated polymer used in a liquid crystal alignment agent of the present invention, at least a part of polymer components with a molecular weight not greater than 7,000 are removed from the untreated polymer after being treated with the co-precipitation solvent.

According to the method for preparing the treated polymer used in the liquid crystal alignment agent of the present invention, based on the total weight of the coprecipitation solvent being 1000 parts by weight, the amount of the poor solvent and poor solvent ranges from 800 to 900 parts by weight.

According to the method for preparing a treated polymer used in a liquid crystal alignment agent of the present invention, the ketones include acetone.

According to the method for preparing the treated polymer used in liquid crystal alignment agents of the present invention, the ethers include tetrahydrofuran.

According to the second embodiment of the present invention, there is provided a treated polymer for liquid crystal alignment agent prepared by a method comprising the following steps: polymerizing a tetracarboxylic dianhydride compound and a diamine compound to Obtaining an untreated polymer; preparing a co-precipitation solvent for the untreated polymer, the co-precipitation solvent containing a poor solvent as a main component and a good solvent as a secondary component, the poor solvent is selected from ketones, ethers or a combination of these; and treating the untreated polymer with the co-precipitation solvent to remove at least a portion of the polymer component having a molecular weight not greater than 3,000 from the untreated polymer to obtain the treated polymer .

According to the third embodiment of the present invention, a liquid crystal alignment agent is provided, which comprises:

A treated polymer is produced by a method comprising the steps of: polymerizing a tetracarboxylic dianhydride compound and a diamine compound to obtain an untreated polymer; preparing a copolymer for the untreated polymer; Precipitation solvent, the coprecipitation solvent contains a poor solvent as a main component and a good solvent as a secondary component, the poor solvent is selected from ketones, ethers or a combination of these; and the coprecipitation solvent is used to process the untreated polymer to obtain the treated polymer by removing at least a portion of polymer components having a molecular weight of not greater than 3,000 from the untreated polymer; and

an organic solvent for dissolving the treated polymer.

According to the liquid crystal alignment agent of the present invention, the treated polymer is selected from polyamic acid, polyimide, or polyimide-based block copolymers.

According to the liquid crystal alignment agent of the present invention, the polyimide block copolymer is selected from polyamic acid block copolymer, polyimide block copolymer, or polyamic acid-polyimide block copolymers.

According to the fourth embodiment of the present invention, there is provided a liquid crystal alignment agent, which includes a polymer obtained by polymerizing a tetracarboxylic dianhydride compound and a diamine compound; and an organic compound used to dissolve the polymer solvent. Wherein, the liquid crystal alignment agent has a T value of 0-1.0%, and the T value is defined by the following steps: the liquid crystal alignment agent is mixed with methanol in a weight ratio of 1:6 to obtain the first solid precipitate containing The first mixture; using a 0.2 μm filter, filter out the first solid precipitate from the first mixture; place the first solid precipitate in an oven and dry at a temperature of 60°C for 12 hours to obtain A dried solid having a _WS weight value; the dried solid is mixed with N-methyl-2-pyrrolidone (N-methyl-2-pyrrolidone, NMP) in a weight ratio of 1:15 to obtain a solution; the The solution is mixed with acetone in a weight ratio of 1:6 to obtain a second mixture containing a second solid precipitate; the second solid precipitate is filtered out from the second mixture using a 0.2 μm filter to obtain a filtrate; the solids content in the filtrate is defined as the W _LS weight value; and the T value is obtained by T=W _LS / _WS .

According to the liquid crystal alignment agent of the present invention, the T value ranges from 0.005% to 0.9%.

According to the liquid crystal alignment agent of the present invention, the T value ranges from 0.01% to 0.8%.

According to the liquid crystal alignment agent of the present invention, the polymer is selected from polyamic acid, polyimide, or polyimide-based block copolymers.

According to the liquid crystal alignment agent of the present invention, the polyimide block copolymer is selected from polyamic acid block copolymer, polyimide block copolymer, or polyamic acid-poly imide block copolymers.

According to a fifth embodiment of the present invention, a liquid crystal alignment film formed from the liquid crystal alignment agent of the present invention is provided.

According to the sixth embodiment of the present invention, there is provided a liquid crystal display element comprising the liquid crystal alignment film of the present invention.

The efficacy of the present invention lies in that the treated polymer used in the liquid crystal alignment agent of the present invention uses the co-precipitation solvent to treat the untreated polymer, and adjusts the characteristics of the subsequent liquid crystal alignment agent to make the alignment agent and the application of the When the alignment film and the display element made by the alignment agent are used, they can indeed have a shorter time for eliminating image sticking, thereby achieving the purpose of the present invention.

Detailed ways

The liquid crystal alignment agent of the present invention comprises a treated polymer (A) and an organic solvent (B) for dissolving the treated polymer (A). The treated polymer (A) is produced by a method comprising the following steps: polymerizing a tetracarboxylic dianhydride compound and a diamine compound to obtain an untreated polymer; preparing an untreated polymer Co-precipitation solvent of substance, this co-precipitation solvent contains poor solvent as main component and good solvent as subcomponent, and this poor solvent is selected from ketones, ethers or these combination; And utilize this coprecipitation solvent to process this an untreated polymer to obtain the treated polymer by removing at least a portion of polymer components having a molecular weight not greater than 3,000 from the untreated polymer.

Preferably, at least a portion of polymer components having a molecular weight of not greater than 7,000 are removed from the untreated polymer after treatment with the co-precipitation solvent.

The liquid crystal alignment agent of the present invention has a T value of 0-1.0%, and the T value is defined by the following steps: the liquid crystal alignment agent is mixed with methanol in a weight ratio of 1:6 to obtain the first solid precipitate containing the second A mixture; using a 0.2 μm filter to filter out the first solid precipitate from the first mixture; placing the first solid precipitate in an oven and drying at a temperature of 60° C. After 12 hours, a Dried solid of W _S weight value; a solution obtained by mixing the dried solid with N-methyl-2-pyrrolidone in a weight ratio of 1:15; mixing the solution with acetone in a weight ratio of 1:6 And obtain the second mixture that contains the second solid precipitate; Utilize the filter of 0.2 μm, filter out this second solid precipitate from this second mixture, obtain a filtrate; The solid content in this filtrate is defined as W _LS weight value; and T value obtained by T=W _LS / _WS .

Each composition of the present invention is described in detail below one by one:

[Treated polymer (A)]

The treated polymer includes polyamic acid (A-1), polyimide (A-2), polyimide-based block copolymer (A-3), or a combination of these. The polyimide block copolymer (A-3) includes polyamic acid block copolymer (A-3-1), polyimide block copolymer (A-3-2), polyamic acid - Polyimide block copolymer (A-3-3) or a combination of these.

[Tetracarboxylic dianhydride compound]

Tetracarboxylic dianhydride compounds suitable for use in the present invention include aliphatic tetracarboxylic dianhydride, alicyclic tetracarboxylic dianhydride, and aromatic tetracarboxylic dianhydride.

Specific examples of aliphatic tetracarboxylic dianhydride include ethane tetracarboxylic dianhydride, butane tetracarboxylic dianhydride, and the like.

Specific examples of alicyclic tetracarboxylic dianhydrides include 1,2,3,4-cyclobutane tetracarboxylic dianhydride, 1,2-dimethyl-1,2,3,4-cyclobutane tetracarboxylic acid Dianhydride, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-dichloro-1,2,3,4-cyclobutanetetracarboxylic di anhydride, 1,2,3,4-tetramethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-cyclopentanetetracarboxylic dianhydride, 1, 2,4,5-cyclohexanetetracarboxylic dianhydride, 3,3',4,4'-dicyclohexyltetracarboxylic dianhydride, cis-3,7-dibutylcycloheptyl-1,5-di Alkene-1,2,5,6-tetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentylacetic dianhydride, 2,3,4,5-tetrahydrofuran tetracarboxylic dianhydride, 3,4- Dicarboxy-1,2,3,4-tetrahydronaphthalene-1-succinic 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-5-methyl-5-(tetrahydro -2,5-Dioxy-3-furyl)-naphtho[1,2-c]-furan-1,3-dione, 1,3,3a,4,5,9b-hexahydro-5- Ethyl-5-(tetrahydro-2,5-dioxo-3-furyl)-naphtho[1,2-c]-furan-1,3-dione, 1,3,3a,4,5 , 9b-hexahydro-7-methyl-5-(tetrahydro-2,5-dioxo-3-furyl)-naphtho[1,2-c]-furan-1,3-dione, 1 , 3,3a,4,5,9b-hexahydro-7-ethyl-5-(tetrahydro-2,5-dioxo-3-furyl)-naphtho[1,2-c]-furan- 1,3-Diketone, 1,3,3a,4,5,9b-hexahydro-8-methyl-5-(tetrahydro-2,5-dioxo-3-furyl)-naphtho[1 ,2-c]-furan-1,3-dione, 1,3,3a,4,5,9b-hexahydro-8-ethyl-5-(tetrahydro-2,5-dioxo-3- Furyl)-naphtho[1,2-c]-furan-1,3-dione, 1,3,3a,4,5,9b-hexahydro-5,8-dimethyl-5-(tetra Hydrogen-2,5-dioxo-3-furyl)-naphtho[1,2-c]-furan-1,3-dione, 5-(2,5-dioxotetrahydrofuranyl)-3-methan Base-3-cyclohexene-1,2-dicarboxylic dianhydride, bicyclo[2.2.2]-oct-7-ene-2,3,5,6-tetracarboxylic dianhydride and the following structural formula ( Compounds shown in I-1) and (I-2):

构造式(I-1)

Constructive formula (I-1)

构造式(I-2)

Constructive formula (I-2)

(In the above formulas (I-1) and (I-2), R ¹ and R ³ are divalent organic groups containing aromatic rings, R ² and R ⁴ are hydrogen atoms or alkyl groups, R ² and R ⁴ can be the same or different, respectively.)

Specific examples of aromatic tetracarboxylic dianhydrides include pyromellitic dianhydride, 3,3',4,4'-benzophenone tetracarboxylic dianhydride, 3,3',4,4'-biphenyl sulfone Tetracarboxylic dianhydride, 1,4,5,8-naphthalene tetracarboxylic dianhydride, 2,3,6,7-naphthalene tetracarboxylic dianhydride, 3,3'-4,4'-diphenylethane Alkane tetracarboxylic dianhydride, 3,3',4,4'-dimethyldiphenylsilane tetracarboxylic dianhydride, 3,3',4,4'-tetraphenylsilane tetracarboxylic dianhydride, 1,2,3,4-furantetracarboxylic dianhydride, 4,4'-bis(3,4-dicarboxyphenoxy)diphenylsulfide dianhydride, 4,4'-bis(3,4- Dicarboxyphenoxy)diphenylsulfone dianhydride, 4,4'-bis(3,4-dicarboxyphenoxy)diphenylpropane dianhydride, 3,3',4,4'-perfluoroisopropylene Base diphthalic dianhydride, 3,3',4,4'-diphenyltetracarboxylic dianhydride, bis(phthalic acid)phenylphosphine oxide dianhydride (bis(phthalic acid)phenylphosphine oxidedianhydride), p- -Phenylene-bis(triphenylphthalic acid)dianhydride, m-phenylene-bis(triphenylphthalic acid)dianhydride, bis(triphenylphthalic acid)-4,4'- Diphenyl ether dianhydride, bis(triphenylphthalic acid)-4,4'-diphenylmethane dianhydride, ethylene glycol-bis(dehydrated trimellitate), propylene glycol-bis(dehydrated trimellitate) triester), 1,4-butanediol-bis(dehydrated trimellitate), 1,6-hexanediol-bis(dehydrated trimellitate), 1,8-octanediol-bis (dehydrated trimellitate), 2,2-bis(4-hydroxyphenyl)propane-bis(dehydrated trimellitate) and the aromatic tetracarboxylic acid represented by the following structural formulas (1) to (4) Compounds such as acid dianhydrides. These tetracarboxylic dianhydride compounds can be used individually by 1 type or in mixture of multiple types.

构造式(1)

Construct (1)

构造式(2)

Construct (2)

构造式(3)

Construct (3)

构造式(4)

Construct (4)

Among the above-mentioned tetracarboxylic dianhydride compounds, 1,2,3,4-cyclobutane tetracarboxylic dianhydride, 1,2,3,4-cyclopentane tetracarboxylic dianhydride, 2,3,5 - tricarboxycyclopentyl acetic dianhydride, 3,4-dicarboxy-1,2,3,4-tetrahydronaphthalene-1-succinic dianhydride, compounds shown in the aforementioned structural formula (I-1) such as The compound shown in the following structural formula (5)～(7), the compound shown in the compound shown in the aforementioned structural formula (I-2), such as the compound shown in the following structural formula (8), pyromellitic dianhydride, 3,3 ', 4,4'-benzophenone tetracarboxylic dianhydride and 3,3',4,4'-biphenylsulfone tetracarboxylic dianhydride are preferred.

构造式(5)

Construct (5)

构造式(6)

Construct (6)

构造式(7)

Construct (7)

构造式(8)

Construct (8)

[Diamine compound]

The diamine compounds used in the present invention include aliphatic or alicyclic diamine compounds, aromatic diamine compounds, or other diamine compounds.

Specific examples of aliphatic or alicyclic diamine compounds are 1,3-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane, 1,6-diaminohexane, 1,7 -Diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane, 4,4-diaminoheptamethylenediamine, 1,4-diaminocyclohexane, isophor Ketonediamine, tetrahydrodicyclopentadienediamine, hexahydro-4,7-methyleneindenylene dimethylenediamine (hexahydro-4,7-methanoindanylenedimethyldiamine), tricyclo[6.2.1.02, 7]-Undecenedimethyldiamine, 4,4'-methylenebis(cyclohexylamine).

Specific examples of aromatic diamine compounds include p-phenylenediamine, m-phenylenediamine, o-phenylenediamine, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylethane, 4 , 4'-diaminodiphenylsulfide, 4,4'-diaminodiphenylsulfone, 3,3'-dimethyl-4,4'-diaminobiphenyl, 4,4'-diamino Benzanilide, 4,4'-diaminodiphenyl ether, 1,5-diaminonaphthalene, 2,2'-dimethyl-4,4'-diaminobiphenyl, 5-amino-1- (4'-aminophenyl)-1,3,3-trimethylhydroindene, 6-amino-1-(4'-aminophenyl)-1,3,3-trimethylhydroindene, 3, 4'-diaminodiphenyl ether, 3,3'-diaminobenzophenone, 3,4'-diaminobenzophenone, 4,4'-diaminobenzophenone, 2,2- Bis[4-(4-aminophenoxy)phenyl]propane, 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane, 2,2-bis(4-aminobenzene base) hexafluoropropane, 2,2-bis[4-(4-aminophenoxy)phenyl]sulfone, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(4- Aminophenoxy) benzene, 1,3-bis(3-aminophenoxy)benzene, 9,9-bis(4-aminophenyl)-10-hydroanthracene, 2,7-diaminoterpene, 9, 9-bis(4-aminophenyl) fluorine, 4,4'-methylene-bis(2-chloroaniline), 2,2',5,5'-tetrachloro-4,4'-diaminobis Benzene, 2,2'-dichloro-4,4'-diamino-5,5'-dimethoxybiphenyl, 3,3'-dimethoxy-4,4'-diaminobiphenyl, 4,4'-(p-phenyleneisopropylidene)bisaniline, 4,4'-(m-phenyleneisopropylidene)bisaniline, 2,2'-bis[4-(4- Amino-2-trifluoromethylphenoxy)phenyl]hexafluoropropane, 4,4'-diamino-2,2'-bis(trifluoromethyl)biphenyl, 4,4'-bis[( 4-Amino-2-trifluoromethyl)phenoxy]-octafluorobiphenyl.

Specific examples of other diamine compounds include 2,3-diaminopyridine, 2,6-diaminopyridine, 3,4-diaminopyridine, 2,4-diaminopyrimidine, 5,6-diamino-2,3 -Dicyanopyrazine, 5,6-diamino-2,4-dihydroxypyrimidine, 2,4-diamino-6-dimethylamino-1,3,5-triazine, 1,4-bis (3-aminopropyl)piperazine, 2,4-diamino-6-isopropoxy-1,3,5-triazine, 2,4-diamino-6-methoxy-1,3, 5-triazine, 2,4-diamino-6-phenyl-1,3,5-triazine, 2,4-diamino-6-methyl-s-triazine, 2,4-diamino- 1,3,5-triazine, 4,6-diamino-2-vinyl-s-triazine, 2,4-diamino-5-phenylthiazole, 2,6-diaminopurine, 5,6 -Diamino-1,3-dimethyluracil, 3,5-diamino-1,2,4-triazole, 6,9-diamino-2-ethoxyacridine lactate, 3, 8-diamino-6-phenylphenanthridine, 1,4-diaminopiperazine, 3,6-diaminoacridine, two (4-aminophenyl) phenylamine and the following structural formula (II-1) And the compound represented by (II-2), that is, diamines containing two primary amino groups and nitrogen atoms other than the primary amino groups in the molecule, and the like.

构造式(II-1)

Constructive formula (II-1)

(In the above formula, ^R5 is a monovalent organic group selected from pyridine, pyrimidine, triazine, piperidine and piperazine with a ring structure containing a nitrogen atom, and X is a divalent organic group.)

构造式(II-2)

Constructive formula (II-2)

(In the above formula, R ⁶ is a divalent organic group with a nitrogen-atom ring structure selected from pyridine, pyrimidine, triazine, piperidine and piperazine, X is a divalent organic group, and R ⁶ present in the majority, Can be the same or different.)

And the compound shown in following structural formula (II-3)～(II-5),

构造式(II-3)

Constructive formula (II-3)

(In the above formula, R ⁷ is a divalent organic group selected from -O-, -COO-, -OCO-, -NHCO-, -CONH- and -CO-, R ⁸ is selected from the group containing steroids (steroids) Skeleton, monovalent organic group of trifluoromethyl group and fluorine group, or an alkyl group with 6 to 30 carbon atoms.)

Construction formula (II-4)

(In the above formula, R ⁹ is a divalent organic group selected from -O-, -COO-, -OCO-, -NHCO-, -CONH- and -CO-, X ₁ and X ₂ are selected from aliphatic ring , an aromatic ring and a heterocyclic ring, R ¹⁰ is an alkyl group selected from 3 to 18 carbon atoms, an alkoxy group with 3 to 18 carbon atoms, a fluoroalkyl group with 1 to 5 carbon atoms, and a carbon atom 1 to 5 fluoroalkoxy, cyano and halogen atoms.)

构造式(II-5)

Constructive formula (II-5)

(In the above formula, R ¹¹ is a hydrocarbon group with 1 to 12 carbon atoms, and the R ¹¹ present in a plurality may be the same or different, p is an integer of 1 to 3, and q is an integer of 1 to 20.)

As well as compounds represented by the following structural formulas (9) to (15), these diamine compounds may be used alone or in combination.

构造式(9)

Construct (9)

构造式(10)

Construct(10)

构造式(11)

Construct (11)

构造式(12)

Construct (12)

构造式(13)

Construct (13)

构造式(14)

Construct(14)

构造式(15)

Construct(15)

(In the above-mentioned structural formula (12), t is an integer of 2 to 12; in the above-mentioned structural formula (13), u is an integer of 1 to 5.)

Among the above-mentioned diamine compounds, p-phenylenediamine, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylsulfide, 1,5-diaminonaphthalene, 2,7- Diaminoterpene, 4,4'-diaminodiphenylether, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 9,9-bis(4-aminophenyl) , 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane, 2,2-bis(4-aminophenyl)hexafluoropropane, 4,4'-(p-phenylene (isopropylidene)bisaniline, 4,4'-(m-phenyleneisopropylidene)bisaniline, 1,4-diaminocyclohexane, 4,4'-methylenebis(cyclohexyl amine), 1,4-bis(4-aminophenoxy)benzene, 4,4'-bis(4-aminophenoxy)biphenyl, 2,6-diaminopyridine, 3,4-diaminopyridine , 2,4-diaminopyrimidine, 3,6-diaminoacridine, the compound shown in the above-mentioned structural formula (9)～(15), the compound shown in the above-mentioned structural formula (II-1) such as the following structural formula In the compound shown in (16), in the compound shown in the above-mentioned structural formula (II-2) as in the compound shown in the following structural formula (17), in the compound shown in the above-mentioned structural formula (II-3) as in the following structural formula Of the compounds represented by (18) to (29), and the compounds represented by the above structural formula (II-4), liquid crystalline diamine compounds represented by the following structural formulas (30) to (41) are preferred.

Construct (22) Construct (23)

Construct (26) Construct (27)

Construct(28) Construct(29)

Construct(30) Construct(31)

Construct(32) Construct(33)

Construct(34) Construct(35)

Construct(36) Construct(37)

Construct(38) Construct(39)

Construct(40) Construct(41)

(In the above structural formulas (38) to (41), v is an integer of 3 to 12.)

[Synthesis of polyamic acid (A-1)]

The untreated polyamic acid (A-1) is obtained by polycondensation reaction of tetracarboxylic dianhydride compound and diamine compound. Wherein, the equivalent ratio of the tetracarboxylic dianhydride compound and the diamine compound used for the polycondensation reaction ranges from 0.2 to 2, preferably 0.3 to 1.2.

In the polycondensation reaction of the untreated polyamic acid (A-1), the reaction temperature of the tetracarboxylic dianhydride compound and the diamine compound in the organic solvent is generally -20 to 150°C, preferably 0 to 100°C . Among them, as long as the organic solvent can dissolve the reactant and the product, it can be used in this application, and there is no other limitation. Specific examples of organic solvents: N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, dimethyl sulfoxide, γ-butyrolactone, tetramethyl Aprotic polar solvents such as urea and hexamethyltriamine phosphate, and phenolic solvents such as m-cresol, xylenol, phenol, and halogenated phenols.

A coprecipitation solvent for the untreated polyamic acid (A-1) containing a poor solvent as a main component and a good solvent as a subcomponent was prepared.

The good solvent is for polymer (A) [that is, polyamic acid (A-1), polyimide (A-2), polyimide block copolymer (A-3), or a combination of these] Solvent with good solubility. Specific examples of the good solvent include the aforementioned organic solvents.

A poor solvent is a solvent having relatively poor solubility for the polymer (A). Specific examples of poor solvents suitable for the present invention include ketones (such as acetone), ethers (such as tetrahydrofuran) or combinations of these.

Preferably, based on the total weight of the co-precipitation solvent being 1000 parts by weight, the amount of the poor solvent is in the range of 800-900 parts by weight.

The untreated polyamic acid (A-1) is poured into the co-precipitation solvent to remove at least a part of polymer components with a molecular weight not greater than 3,000 from the untreated polyamic acid (A-1), A precipitate was obtained; the precipitate was then dried under reduced pressure to obtain the treated polyamic acid (A-1). Preferably, at least a part of the polymer component having a molecular weight of not more than 7,000 is removed from the untreated polyamic acid (A-1) after the treatment with the coprecipitation solvent.

[Synthesis of polyimide (A-2)]

The polyimide (A-2) of the present invention is obtained by further subjecting the polyamic acid (A-1) to a dehydration ring-closing (imidization) treatment.

The imidization treatment method of polyamic acid (A-1) is, for example: dissolving polyamic acid polymer (A-1) in an organic solvent, and heating in the presence of a dehydrating agent and an imidization catalyst Dehydration ring closure reaction. The heating temperature of the imidization treatment is generally 40-200°C, preferably 80-150°C.

If the reaction temperature of the imidization treatment is lower than 40° C., the dehydration ring-closure reaction cannot proceed sufficiently; if the reaction temperature exceeds 200° C., the weight average molecular weight of the obtained polyimide (A-2) is low.

Specific examples of dehydrating agents suitable for imidization treatment include acid anhydride compounds such as acetic anhydride, propionic anhydride, and trifluoroacetic anhydride. Based on 1 mole of the polyamic acid (A-1), the amount of the dehydrating agent preferably ranges from 0.01 to 20 moles. Specific examples of the imidization catalyst used include tertiary amines such as pyridine, collidine, lutidine, and triethylamine. Based on 1 mole of the dehydrating agent, the amount of the imidization catalyst preferably ranges from 0.5 to 10 moles. The specific example of the solvent used in the imidization treatment is the same as the solvent used in the polycondensation reaction of the aforementioned polyamic acid (A-1), and will not be repeated here.

[Synthesis of polyimide-based block copolymer (A-3)]

Polyimide-based block copolymers (A-3) include polyamic acid block copolymers (A-3-1), polyimide block copolymers (A-3-2), poly Amic acid-polyimide block copolymer (A-3-3), or a combination of these.

In the synthetic reaction of polyimide series block copolymer (A-3), will be selected from aforementioned polyamic acid polymer (A-1), polyimide polymer (A-2), four Carboxylic acid dianhydride compound and diamine compound are obtained through further polycondensation reaction in an organic solvent. For example: the first polyamic acid and the second polyamic acid (A-1) with different terminal groups and different structures; the first polyamic acid and the second polyimide (A-2) with different terminal groups and different structures ; Polyamic acid (A-1) and polyimide (A-2) with different terminal groups and different structures; polyamic acid (A-1), tetracarboxylic dianhydride compound and diamine compound, wherein four At least one of the carboxylic acid dianhydride compound and the diamine compound is different from the structure of the tetracarboxylic dianhydride compound and the diamine compound used in the condensation reaction of the polyamic acid (A-1); the polyimide (A-2), Tetracarboxylic dianhydride compounds and diamine compounds, wherein at least one of the tetracarboxylic dianhydride compounds and diamine compounds is used for the condensation reaction with polyimide (A-2) and the tetracarboxylic dianhydride compounds and diamine compounds Different structures of amine compounds; polyamic acid (A-1), polyimide (A-2), tetracarboxylic dianhydride compound and diamine compound, wherein at least one of tetracarboxylic dianhydride compound and diamine compound The structure of the tetracarboxylic dianhydride compound and diamine compound used in the condensation reaction of polyamic acid (A-1) and polyimide (A-2) is different; the first polyamic acid and the second polyamic acid with different structures Amic acid (A-1), tetracarboxylic dianhydride compound, and diamine compound; first polyamic acid and second polyimide (A-2), tetracarboxylic dianhydride compound, and diamine compound having different structures ; The first polyamic acid and the second polyamic acid (A-1) and the diamine compound whose terminal group is an anhydride group and different in structure; the first polyamic acid and the second polyamide whose terminal group is an amine group and different in structure Acid (A-1) and tetracarboxylic dianhydride compound; first polyimide and second polyimide (A-2) and diamine compound with terminal group being acid anhydride group and different structures; terminal group being amine The first polyimide and the second polyimide (A-2), tetracarboxylic dianhydride compounds, and the like having different groups and structures.

In the polycondensation reaction of the polyimide-based block copolymer (A-3), the reaction temperature is generally 0-200°C, preferably 0-100°C. The specific example of the solvent used is the same as the solvent used in the polycondensation reaction of the aforementioned polyamic acid (A-1), and will not be repeated here.

[Terminal modified polymer]

The polyamic acid (A-1), polyimide (A-2) and polyimide-based block copolymer (A-3) used in the present invention can also be terminal after molecular weight adjustment. Modified polymers. By using the end-modified polymer, properties such as the coating characteristics of the liquid crystal alignment agent can be improved without detracting from the effect of the present invention. Such end-modified polymers can be produced by adding monofunctional compounds such as monobasic anhydrides, monoamine compounds, and monoisocyanate compounds to the reaction system during the synthesis reaction of polyamic acid. Among them, specific examples of monobasic acid anhydrides: maleic anhydride, phthalic anhydride, itaconic anhydride, n-decyl succinic anhydride, n-dodecyl succinic anhydride, n-tetradecyl succinic anhydride, n-hexadecyl succinic anhydride anhydride, etc. Specific examples of monoamine compounds include aniline, cyclohexylamine, n-butylamine, n-pentylamine, n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine, n-decylamine, n-undecylamine, n-dodecylamine , n-tridecylamine, n-tetradecylamine, n-pentadecylamine, n-hexadecylamine, n-heptadecylamine, n-octadecylamine, n-eicosylamine, etc. Specific examples of the monoisocyanate compound include phenyl isocyanate, naphthyl isocyanate, and the like.

[Organic solvent (B)]

In the liquid crystal alignment agent of the present invention, specific examples of the organic solvent (B) used are: N-methyl-2-pyrrolidone, γ-butyrolactone, γ-butyrolactam, N,N-dimethylformamide , N, N-dimethylacetamide, 4-hydroxy-4-methyl-2-pentanone, ethylene glycol monomethyl ether, butyl lactate, butyl acetate, methyl methoxypropionate, ethyl Ethyl oxypropionate, ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol n-propyl ether, ethylene glycol isopropyl ether, ethylene glycol n-butyl ether (butyl cellosolve), ethylene glycol Alcohol dimethyl ether, ethylene glycol ethyl ether acetate, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol Alcohol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, etc.

[Additive (C)]

In addition, the liquid crystal alignment agent of the present invention can add functional silane compounds or epoxy compounds to improve the adhesion to the surface of the substrate within the scope of not impairing the desired physical properties.

Specific examples of the functional silane-containing compound: 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 2-aminopropyltrimethoxysilane, 2-aminopropyltriethoxysilane N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, 3-ureido Propyltrimethoxysilane (3-ureidopropyltrimethoxysilane), 3-ureidopropyltriethoxysilane, N-ethoxycarbonyl-3-aminopropyltrimethoxysilane, N-ethoxycarbonyl-3- Aminopropyltriethoxysilane, N-triethoxysilylpropyltriethylenetriamine, N-trimethoxysilylpropyltriethylenetriamine, 10-trimethoxy Silyl-1,4,7-triazadecane (10-trimethoxysilyl-1,4,7-triazadecane), 10-triethoxysilyl-1,4,7-triazadecane, 9 -Trimethoxysilyl-3,6-diazanonyl acetate (9-trimethoxysilyl-3,6-diazanonyl acetate), 9-triethoxysilyl-3,6-diazanonyl acetate ester, N-benzyl-3-aminopropyltrimethoxysilane, N-benzyl-3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltriethoxysilane, N-bis(oxyethylene)-3-aminopropyltrimethoxysilane, N-bis(oxyethylene)-3-aminopropyltriethoxy base silane, etc.

In addition, specific examples of the epoxy compound: ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, poly Propylene Glycol Diglycidyl Ether, Neopentyl Glycol Diglycidyl Ether, 1,6-Hexanediol Diglycidyl Ether, Glycerol Diglycidyl Ether, 2,2-Dibromonew Pentylene glycol diglycidyl ether, 1,3,5,6-tetraepoxypropyl-2,4-hexanediol, N,N,N',N'-tetraepoxypropyl-m- Xylenediamine, 1,3-bis(N,N-diepoxypropylaminomethyl)cyclohexane, N,N,N',N'-tetraepoxypropyl-4,4'-di Aminodiphenylmethane, 3-(N-allyl-N-epoxypropyl)aminopropyltrimethoxysilane, 3-(N,N-diepoxypropyl)aminopropyltrimethoxysilane wait.

[Liquid crystal alignment agent]

The liquid crystal alignment agent of the present invention is prepared by dissolving the treated polymer (A) and additives (C) in an organic solvent (B).

The preparation temperature of the liquid crystal alignment agent of the present invention is preferably 0-200°C, more preferably 20-60°C.

The solid content in the liquid crystal alignment agent of the present invention is adjusted according to properties such as viscosity and volatility. Generally, it is 1-15 weight%, Preferably it is 2-15 weight%, More preferably, it is 3-15 weight%. That is to say, when the liquid crystal alignment agent of the present invention is coated on the surface of the substrate to form a coating film of the liquid crystal alignment film, when the solid content of the liquid crystal alignment agent is between 1% and 15% by weight, the coating properties of the liquid crystal alignment agent will be improved. better.

The range of T value of the liquid crystal alignment agent of the present invention is 0-1.0%, preferably 0.005%-0.9%, more preferably 0.01%-0.8%. The T value is defined by the following steps: mixing the liquid crystal alignment agent with methanol in a weight ratio of 1:6 to obtain a first mixture containing a first solid precipitate; using a 0.2 μm filter, from the first mixture The first solid precipitate was filtered out; the first solid precipitate was placed in an oven and dried at a temperature of 60° C., and after 12 hours, a dried solid with _{a WS} weight value was obtained; the dried solid was mixed with N -Methyl-2-pyrrolidone is mixed in a weight ratio of 1:15 to obtain a solution; the solution is mixed with acetone in a weight ratio of 1:6 to obtain a second mixture containing a second solid precipitate; using 0.2 μm filter, filter out the second solid precipitate from the second mixture to obtain a filtrate; the solid content in the filtrate is defined as W _LS weight value; and obtained by T=W _LS / _WS T value.

If the T value>1.0%, the formed liquid crystal alignment film is prone to problems such as a long time for image sticking to be eliminated.

[Formation of liquid crystal alignment film]

The liquid crystal alignment film of the present invention is formed by the above-mentioned liquid crystal alignment agent, and further, the preparation method of the liquid crystal alignment film is to place the liquid crystal alignment agent of the present invention on one side of the substrate provided with a transparent conductive film Roll coating method, spin coating method, printing method, ink-jet method and the like are used to coat the substrate, and then the coated surface is heated to form a coating film.

膜(

为美国PPG公司拥有的注册商标)、由氧化铟-氧化锡(In₂O₃-SnO₂)构成的ITO膜等。Specific examples of the aforementioned substrates include glass such as alkali-free glass, soda-lime glass, hard glass (Pileus glass), quartz glass, polyethylene terephthalate, polybutylene, etc. used in liquid crystal display devices. Plastic transparent substrates such as terephthalate, polyethersulfone, polycarbonate, etc. The transparent conductive film provided on one side of the substrate can be made of tin oxide (SnO ₂ ).

membrane(

is a registered trademark owned by PPG Corporation of the United States), an ITO film made of indium oxide-tin oxide (In ₂ O ₃ -SnO ₂ ), and the like.

Before coating the liquid crystal alignment agent, in order to improve the adhesion between the substrate surface and the transparent conductive film, a functional silane compound or a functional titanium compound may be pre-coated on the substrate surface.

The heat treatment for forming the alignment film includes pre-bake and post-bake after the coating of the liquid crystal alignment agent. The pre-heat treatment can volatilize the organic solvent to form the coating layer of the alignment film. Pre-heat The treatment temperature is generally 30-120°C, preferably 40-110°C, more preferably 50-100°C.

In addition, after the alignment agent forms the coating film layer of the alignment film, further post-heat treatment can be performed to perform a dehydration ring-closure (imidization) reaction to form an imidized coating film layer of the alignment film. The post-heating temperature is generally 150-300°C, preferably 180-280°C, more preferably 200-250°C.

The film thickness of the formed alignment film coating layer is preferably 0.001-1 μm, more preferably 0.005-0.5 μm.

The formed alignment film coating layer can be wound on the drum with cloth made of nylon, rayon, cotton and other fibers according to needs, and the alignment treatment is carried out by rubbing in a certain direction, so that the alignment of liquid crystal molecules can be given to the coating layer. A liquid crystal alignment film is formed on it. In addition, the method of imparting the alignment energy of liquid crystal molecules is achieved by forming a protrusion or a pattern on at least one substrate forming an alignment film. This method is based on MVA (Multi-domain Vertical Alignment) or PVA (Patterned Vertical Alignment) known.

[LCD display element]

Two substrates with the above-mentioned liquid crystal alignment film are produced, and a gap (cell gap) is interposed between the two substrates to make facing arrangements, and the surrounding parts of the two substrates are bonded together with a sealer (sealer) sealant ( Only one liquid crystal injection hole is left), and then, after injecting liquid crystal into the gap defined by the surface of the substrate and the sealant, the injection hole is sealed to form a liquid crystal cell. Then, on the outer surface of the liquid crystal chamber, that is, on the other side surfaces of the substrates constituting the liquid crystal chamber, polarizing plates are pasted to obtain a liquid crystal display element.

The sealant material can use a general epoxy resin curing agent, and the spacer material can use glass beads, plastic beads, or photosensitive epoxy resin. Examples of liquid crystals: nematic liquid crystals, specific examples: Schiff Base liquid crystals, Azoxy liquid crystals, Biphenyl liquid crystals, Phenylcyclohexane liquid crystals Liquid crystals, Ester liquid crystals, Terphenyl liquid crystals, Biphenylcyclohexane liquid crystals, Pyrimidine liquid crystals, Dioxane liquid crystals, Dicyclooctane ( Bicyclooctane)-based liquid crystals, cubane-based liquid crystals, and the like. Among the above-mentioned liquid crystals, cholesteric liquid crystals such as Cholesteryl Chloride, Cholesteryl Nonanoate, Cholesteryl Carbonate, etc. can be added, and the trade name "C- 15", "CB-15" (manufactured by Merck & Co., Ltd.), a chiral agent, etc. are sold. In addition, the polarizing plate attached to the outer surface of the liquid crystal cell is, for example, a polarizing film called an H film that stretches and aligns polyvinyl alcohol while absorbing iodine, and sandwiches it with a cellulose acetate protective film. The polarizing plate or the polarizing plate formed by the H film itself.

Example

The present invention will be further described with reference to the following examples, but it should be understood that these examples are for illustrative purposes only and should not be construed as limitations on the practice of the present invention.

The compound shown in the aforementioned structural formula (15) used in the following examples (hereinafter referred to as C7CDA) is prepared according to the method disclosed in Japanese Patent Application Laid-Open No. 2003-96034, and the compound shown in the aforementioned structural formula (14) (hereinafter referred to as BCDA) is prepared according to the method disclosed in Japanese Patent Laid-Open No. 2002-162630.

<Comparative Synthesis Example 1>

Set nitrogen inlet, stirrer, heater, condenser and thermometer on a four-necked conical flask with a volume of 500 milliliters, and introduce nitrogen, and add 7CDA 0.74g (0.0015mole), p-phenylenediamine (hereinafter referred to as PDA) 5.24 g (0.0485 mole), and 75 g of solvent N-methyl-2-pyrrolidone (hereinafter referred to as NMP). First, stir at room temperature to dissolve C7CDA and PDA in NMP, then add pyromellitic dianhydride (hereinafter referred to as PMDA) 10.91g (0.05mole) and NMP 20g, and react at room temperature for 2 hours. , the reaction solution was poured into 1500ml of water, the polymer was precipitated and filtered, and then the filtered polymer was placed in a vacuum oven and dried at a temperature of 60°C to obtain polyamic acid (A-1-a ).

<Comparative Synthesis Example 2>

Comparative synthetic example 2 is to prepare polyamic acid (A-1-b) in the same manner as comparative synthetic example 1, and the difference is: this synthetic example is to first make the compound (hereinafter referred to as VEDA) shown in structural formula (24) ) 5.64g (0.01mole), 4,4'-diaminodiphenylmethane (hereinafter referred to as DDM) 7.93g (0.04mole) are dissolved in NMP 100g, then add cyclobutane tetracarboxylic dianhydride (hereinafter referred to as CBTA ) 9.81g (0.05mole) and NMP 30g.

<Comparative Synthesis Example 3>

Set nitrogen inlet, stirrer, heater, condenser and thermometer on a four-necked conical flask with a volume of 500 ml, and introduce nitrogen, and add BCDA 1.13g (0.0025mole), PDA 5.14g (0.0475mole), and solvent NMP 45g. First, the system is heated to 60° C. and stirred so that BCDA and PDA are dissolved in NMP, and then 3,4-dicarboxy-1,2,3,4-tetrahydronaphthalene-1-succinic dianhydride ( Hereinafter referred to as TDA) 15.01g (0.05mole) and NMP 20g, reacted at room temperature for 6 hours. Then add 97g of NMP, 6g of acetic anhydride, and 20g of pyridine, heat up to 60°C and continue to stir for 2 hours for imidization. After the reaction, pour the reaction solution into 1500ml of water, precipitate the polymer and filter it. The filtered polymer was placed in a vacuum oven and dried at a temperature of 60° C. to obtain polyimide (A-2-a).

<Comparative Synthesis Example 4>

Comparative synthesis example 4 is to prepare polyimide (A-2-b) in the same manner as comparative synthesis example 3, the difference is: this synthesis example is to make VEDA 4.23g (0.0075mole), 4,4 ' - Dissolve 8.51g (0.0425mole) of diaminodiphenyl ether (hereinafter referred to as ODA) in 60g of NMP, then add 15.01g (0.05mole) of TDA and 25g of NMP.

<Comparative Synthesis Example 5>

First, prepare polyamic acid (A-1-c) and polyamic acid (A-1-d) in the same manner as Comparative Synthesis Example 1, the difference is: prepare polyamic acid polymer (A-1- c) Dissolve VEDA 0.71g (0.00125mole), 2,2'-bis[4-(4-aminophenoxy)phenyl]propane (hereinafter referred to as BAPP) 20.01g (0.04875mole) in NMP 160g In, add again 3,3',4,4'-benzophenone tetracarboxylic dianhydride (hereinafter referred to as BTDA) 15.95g (0.0495mole) and NMP 50g; Prepare polyamic acid polymer (A-1-d ) is to dissolve C7CDA 0.61g (0.00125mole), DDM 9.67g (0.04875mole) in NMP 120g, and then add BTDA 16.27g (0.0505mole) and NMP 30g.

Then, a nitrogen inlet, a stirrer, a heater, a condenser tube and a thermometer are set on a four-necked conical flask with a volume of 500 milliliters, and nitrogen is introduced, and 3 g of the polyamic acid (A-1-c) obtained above is added, and Solvent NMP 17g, and stir at room temperature to dissolve polyamic acid (A-1-c) in NMP, then add 3g of polyamic acid (A-1-d) and 17g of NMP obtained above, at 60°C React for 6 hours. After the reaction is over, pour the reaction solution into 1500ml of water to precipitate the polymer and filter it. Then put the filtered polymer into a vacuum oven and dry it at 60°C to obtain polyamide. Acid block copolymer (A-3-1-a).

<Comparative Synthesis Example 6>

First, a nitrogen inlet, a stirrer, a heater, a condenser tube and a thermometer are set on a four-necked conical flask with a volume of 500 milliliters, and nitrogen is introduced, and BCDA 0.57g (0.00125mole) and PDA 5.27g (0.04875mole) are added, and solvent NMP 100g, and stirred at room temperature to dissolve BCDA and PDA in NMP, then added BTDA 15.95g (0.0495mole) and NMP 25g, reacted at room temperature for 2 hours, then added NMP 94g, acetic anhydride 15g, and 12g of pyridine, and the system was heated up to 110°C and continued to stir for 2 hours to carry out the imidization reaction. The polymer was placed in a vacuum oven and dried at a temperature of 60° C. to obtain polyimide (A-2-c).

In addition, the polyimide polymer (A-2-d) was prepared in the same manner as above, except that at this time, 0.86g (0.00175mole) of C7CDA and 9.57g (0.04825mole) of DDM were dissolved in In NMP 120g, add BTDA16.27g (0.0505mole) and NMP 30g.

Then, a nitrogen inlet, a stirrer, a heater, a condenser tube and a thermometer are set on a four-necked conical flask with a volume of 500 milliliters, and nitrogen is introduced, and the feed composition is added to include: the above-mentioned polyimide (A-2 -c) 3g, and solvent NMP 17g, stirred at room temperature until dissolved. Then add 3g of the polyimide (A-2-d) obtained above and 17g of NMP, and react at 60°C for 6 hours. After the reaction, pour the reaction solution into 1500ml of water, precipitate the polymer, and filter the obtained polymer. Put the material into a vacuum oven and dry it at a temperature of 60° C. to obtain a polyimide-polyimide block copolymer (A-3-2-a).

<Comparative Synthesis Example 7>

First, a nitrogen inlet, a stirrer, a heater, a condenser tube and a thermometer are set on a four-necked conical flask with a volume of 500 milliliters, and nitrogen is introduced, and BCDA 2.26g (0.005mole) and PDA 5.27g (0.04875mole) are added, And solvent NMP 100g, and stirred at room temperature to dissolve BCDA and PDA in NMP, then added BTDA 15.95g (0.0495mole) and NMP 35g, reacted at room temperature for 2 hours, after the reaction, pour the reaction solution into 1500ml The polymer was precipitated in water, and the obtained polymer was filtered and placed in a vacuum oven for drying at a temperature of 60° C. to obtain polyamic acid (A-1-e).

In addition, a nitrogen inlet, a stirrer, a heater, a condenser tube and a thermometer are set on a four-necked conical flask with a volume of 500 milliliters, and nitrogen is introduced, and BCDA 2.26g (0.005mole) and DDM 8.92g (0.045mole) are added, And solvent NMP 100g, and stir at room temperature to dissolve BCDA and DDM in NMP, then add BTDA 16.27g (0.0505mole) and NMP 55g, react at room temperature for 2 hours, then add NMP 94g, acetic anhydride 15g, and 12g of pyridine, and the system was heated to 110°C and continued to stir for 2 hours to carry out the imidization reaction. The polymer was placed in a vacuum oven and dried at a temperature of 60° C. to obtain polyimide (A-2-e).

Then, a nitrogen inlet, a stirrer, a heater, a condenser tube and a thermometer are set on a four-necked conical flask with a volume of 500 milliliters, and nitrogen is introduced, and the feed composition is added to include: the above-mentioned polyimide (A-2 -e) 3g, and solvent NMP 17g, stirred at room temperature until dissolved. React 3g of the polyamic acid (A-1-e) obtained above with 17g of NMP at 60°C for 6 hours. After the reaction, pour the reaction solution into 1500ml of water to precipitate the polymer. Filter the obtained polymer and place it in a vacuum oven , after drying at a temperature of 60° C., the polyamic acid-polyimide block copolymer (A-3-3-a) can be obtained.

<Synthesis Example 1>

100 parts by weight of the polyamic acid (A-1-a) obtained in Comparative Synthesis Example 1 was added to the co-solvent of 850 parts by weight of acetone/150 parts by weight of NMP, and after continuous stirring for 30 minutes, the precipitate was taken out and placed in a vacuum The polyamic acid (A-1-a') can be obtained after the solvent is devolatilized at a temperature of 60° C. in an oven.

<Synthesis Example 2>

100 parts by weight of the polyamic acid (A-1-b) obtained in Comparative Synthesis Example 2 was added to the co-solvent of 900 parts by weight of acetone/100 parts by weight of NMP, and after continuous stirring for 30 minutes, the precipitate was taken out and placed in a vacuum oven , after the solvent was devolatilized at a temperature of 60° C., and the above steps of dissolution, precipitation, and volatilization were repeated once, polyamic acid (A-1-b′) could be obtained.

<Synthesis Example 3>

100 parts by weight of polyimide (A-2-a) gained in Comparative Synthesis Example 3 was added to the co-solvent of 800 parts by weight of acetone/200 parts by weight of NMP, and after continuing to stir for 30 minutes, the precipitate was taken out and placed in In a vacuum oven, after the solvent is devolatilized at a temperature of 60°C, the above steps of dissolution, precipitation, and volatilization are repeated twice, and then added to a co-solvent of 950 parts by weight of acetone/50 parts by weight of NMP, and continuously stirred for 30 minutes Finally, the precipitate was taken out and placed in a vacuum oven, and the solvent was devolatilized at a temperature of 60° C., and the above steps of dissolution, precipitation and devolatilization were repeated twice to obtain polyimide (A-2-a′).

<Synthesis Example 4>

100 parts by weight of polyimide (A-2-b) gained in Comparative Synthesis Example 4 was added to the co-solvent of 800 parts by weight of acetone/200 parts by weight of NMP, and after continuous stirring for 30 minutes, the precipitate was taken out and placed in In a vacuum oven, after the solvent is devolatilized at a temperature of 60°C, the above steps of dissolution, precipitation, and volatilization are repeated three times, and then added to a co-solvent of 900 parts by weight of acetone/100 parts by weight of NMP, while continuously stirring for 30 minutes, The precipitate was taken out and placed in a vacuum oven, and after the solvent was devolatilized at a temperature of 60° C., the above steps of dissolution, precipitation and devolatilization were repeated four times to obtain polyimide (A-2-b′).

<Synthesis Example 5>

100 parts by weight of the polyamic acid block copolymer (A-3-1-a) gained in Comparative Synthesis Example 5 was added to the co-solvent of 500 parts by weight of tetrahydrofuran/400 parts by weight of acetone/100 parts by weight of NMP, and After continuous stirring for 30 minutes, the precipitate was taken out and placed in a vacuum oven, and after the solvent was devolatilized at a temperature of 60°C, the above steps of dissolution, precipitation, and volatilization were repeated twice to obtain the polyamic acid block copolymer (A -3-1-a').

<Synthesis Example 6>

100 parts by weight of the polyimide-polyimide block copolymer (A-3-2-a) obtained in Comparative Synthesis Example 6 was added to 700 parts by weight of tetrahydrofuran/200 parts by weight of acetone/100 parts by weight of NMP In the co-solvent, and after continuous stirring for 30 minutes, the precipitate was taken out and placed in a vacuum oven, and the solvent was devolatilized at a temperature of 60°C. After repeating the above steps of dissolution, precipitation and devolatilization three times, the polyimide- Polyimide block copolymer (A-3-2-a').

<Synthesis Example 7>

Add 100 parts by weight of the polyamic acid-polyimide block copolymer (A-3-3-a) obtained in Comparative Synthesis Example 7 to a total of 600 parts by weight of tetrahydrofuran/300 parts by weight of acetone/100 parts by weight of NMP. solvent, and after 30 minutes of continuous stirring, take out the precipitate and put it in a vacuum oven, and after the solvent is devolatilized at a temperature of 60°C, after repeating the above steps of dissolution, precipitation, and devolatilization three times, polyamic acid-polyimide Amine block copolymer (A-3-3-a').

[Preparation of liquid crystal alignment agent and liquid crystal display element]

In the following examples and comparative examples, the prepared liquid crystal alignment agent and liquid crystal display element were further evaluated according to the following evaluation methods.

【Evaluation method】

(1) Solid content analysis of filtrate

The liquid crystal alignment agent prepared below was mixed with methanol at a weight ratio of 1:6 to obtain a first mixture containing a first solid precipitate. Use a 0.2 μm filter (manufactured by Critical Process Filtration, Inc., model ETM, PTFE material, pore size 0.2 μm) to filter out the first solid precipitate from the first mixture, and then place it in an oven at a temperature of 60° C. Drying was carried out for 12 hours to obtain a dry solid. The weight of the dry solid is defined and indicated as _WS .

The dry solid was mixed with NMP at a weight ratio of 1:15 to form a solution, and then the solution was mixed with acetone at a weight ratio of 1:6 to obtain a second mixture containing a second solid precipitate. The second solid precipitate was filtered out from the second mixture using a 0.2 μm filter (manufactured by Critical Process Filtration, Inc., model ETM, PTFE material, pore size 0.2 μm) to obtain a filtrate. The weight of the filtrate is defined and indicated as W _L .

Get 5 milliliters of filtrate and put it into an aluminum pan, place it on a heater, and dry it for 30 minutes with a temperature of 225° C. During the process, accurately weigh the net weight (W ₀ ), the weight before drying (W ₁ ), and the weight after drying (W ₂ ) of the aluminum pan, and calculate the solid content of the filtrate with the following calculation formula (E1) (TS), the unit is weight %; and the following calculation formula (E2) calculates the solid content (W _LS ) of the filtrate, the unit is gram.

TS=[(W ₂ -W ₀ )/(W ₁ -W ₀ )]×100% by weight (E1)

W _LS ＝W _L ×TS (E2)

(2) Pretilt angle

According to the method described in "T.J.Scheffer, et.al., J.Appl.Phys., vol.19, 2013 (1980)", the pretilt angle of the liquid crystal alignment film was measured by the crystal rotation method of He-Ne laser. (manufactured by CHUO PRECISION INDUSTRIAL CO., LTD., model OMS-CM4RD)

(3) Afterimage elimination time

At an ambient temperature of 70°C, a 30 Hz, 3.0 volt rectangular wave overlapping 3.0 volts DC and 6.0 volts AC (peak-to-peak) was applied to the prepared liquid crystal chamber for 20 hours, then the voltage was turned off, and the turn-off voltage was measured visually The time required from start to afterimage removal.

○: Afterimage elimination time < 20 seconds.

Δ: Afterimage removal time is 20 to 90 seconds.

×: Afterimage elimination time > 90 seconds.

<Example 1>

The polyamic acid (A-1-a') that 100 weight parts above-mentioned synthetic example 1 gains is dissolved in the co-solvent of NMP 1250 weight parts/ethylene glycol n-butyl ether (hereinafter referred to as BC) 250 weight parts at room temperature , to obtain an alignment agent solution.

First, the solution was coated on an indium tin oxide (indium-tin-oxide; ITO) glass substrate with a printing machine (manufactured by Nippon Photo Printing Co., Ltd., model S15-036). Then, pre-bake (pre-bake) on a heating plate at a temperature of 100°C for 5 minutes, and post-bake (post-bake) in a circulating oven at a temperature of 220°C for 30 minutes to obtain a film . The film was measured with a film thickness measuring instrument (manufactured by KLA-Tencor, model Alpha-step 500), and its film thickness was

Next, on the surface of the film, use a liquid crystal alignment film machine (manufactured by Iinuma Seisakusho, model RM02-11) to perform alignment. The moving speed of the platform is 50mm/sec. Prepare two liquid crystal alignment film glass substrates by the above steps, one glass substrate is coated with hot pressure glue, and the other glass substrate is sprinkled with a 4 μm spacer (spacer), and the two sheets of glass are bonded along the direction perpendicular to each other (leaving only The next liquid crystal injection port), and then apply a pressure of 10kg with a hot press, and perform hot pressing at a temperature of 150°C. Then, use a liquid crystal injection machine (manufactured by Shimadzu Corporation, model ALIS-100X-CH) to inject liquid crystals, then seal the liquid crystal injection port with ultraviolet (UV) curing glue, and cure the curing glue with ultraviolet light. The liquid crystal is tempered in an oven at a temperature of 60° C. for 30 minutes to complete the cell, and further produce a liquid crystal display element.

Finally, the prepared liquid crystal alignment agent and liquid crystal display element were subjected to various property tests according to the above-mentioned evaluation methods, and the evaluation results are shown in Table 1 below.

<Examples 2 to 10>

Examples 2 to 10 prepared the liquid crystal alignment agent and the liquid crystal display element of the present invention in the same manner as in Example 1, except that the polymer (A), organic solvent (B) and/or additive ( C) Types and dosages. In addition, the liquid crystal alignment agents and liquid crystal display elements prepared in these examples were also tested in the same evaluation manner. The detailed information and subsequent evaluation results are recorded in Table 1 below.

It should be noted that, in the preparation process of Example 2 and Example 4, the procedure of subsequent alignment engineering is also omitted.

<Comparative Examples 1 to 8>

Comparative Examples 1 to 8 prepared liquid crystal alignment agents and liquid crystal display elements in the same manner as in Example 1, except that the polymer (A), organic solvent (B) and/or additive (C) used therein In addition, these comparative examples also tested the prepared liquid crystal alignment agent and liquid crystal display elements in the same evaluation method, and the detailed information and evaluation results are recorded in Table 1 below.

It should be noted that, in the preparation process of Comparative Example 2 and Comparative Example 4, the procedure of subsequent alignment engineering is also omitted.

It can be seen from the above Table 1 that the image sticking elimination time of the liquid crystal display elements of Comparative Examples 1 to 7 is all greater than 90 seconds, and the image sticking elimination time of the liquid crystal display element of Comparative Example 8 is between 20-90 seconds. The image sticking elimination times of the liquid crystal display elements of Examples 1 to 10 are all less than 20 seconds. This shows that by using the liquid crystal alignment agent of the present invention, the image sticking problem has indeed been greatly improved. Furthermore, Table 1 shows that the pretilt angle of the liquid crystal alignment film of the present invention is not much different from that of the existing liquid crystal alignment film, that is to say, they all conform to the current industry standard.

However, the above-mentioned person is only a preferred embodiment of the present invention, and the scope of the present invention can not be limited with this, that is, the simple equivalent changes and modifications made according to the patent scope of the present invention and the content of the description of the invention are still the same. It belongs to the scope covered by the patent of the present invention.

Claims (16)

1. A method for preparing a treated polymer for liquid crystal alignment agent, characterized in that, polymerizing the tetracarboxylic dianhydride compound and the diamine compound to obtain an untreated polymer; preparing a co-precipitation solvent for the untreated polymer, the coprecipitation solvent comprising a poor solvent as a major component and a good solvent as a minor component, the poor solvent being selected from ketones, ethers or a combination of these; and Treating the untreated polymer with the co-precipitation solvent to remove at least a portion of polymer components having a molecular weight of not greater than 3,000 from the untreated polymer to obtain the treated polymer. 2. The method for preparing a treated polymer for liquid crystal alignment agent according to claim 1, characterized in that, after being treated with the co-precipitation solvent, at least a part of the polymer having a molecular weight not greater than 7,000 polymer components. 3. The method for preparing the treated polymer for liquid crystal alignment agent according to claim 1, characterized in that, based on the total weight of the co-precipitation solvent being 1000 parts by weight, the amount of the poor solvent ranges from 800 to 900 parts by weight. parts by weight. 4 . The method for preparing a treated polymer used in a liquid crystal alignment agent according to claim 1 , wherein the ketones comprise acetone. 5 . The method for preparing a treated polymer used in liquid crystal alignment agents according to claim 1 , wherein the ethers comprise tetrahydrofuran. 6. A treated polymer for a liquid crystal alignment agent, characterized in that the polymer is prepared by the method according to any one of claims 1 to 5. 7. A liquid crystal alignment agent, characterized in that it comprises the following: A treated polymer obtained by a method comprising: polymerizing a tetracarboxylic dianhydride compound and a diamine compound to obtain an untreated polymer; preparing a compound for the untreated polymer A co-precipitation solvent, the co-precipitation solvent contains a poor solvent as a main component and a good solvent as a secondary component, the poor solvent is selected from ketones, ethers or a combination of these; and the coprecipitation solvent is used to process the an untreated polymer to obtain the treated polymer by removing at least a portion of polymer components having a molecular weight of not more than 3,000 from the untreated polymer; and An organic solvent used to dissolve the treated polymer. 8. The liquid crystal alignment agent according to claim 7, wherein the treated polymer is selected from polyamic acid, polyimide, or polyimide-based block copolymers. 9. The liquid crystal alignment agent according to claim 8, wherein the polyimide block copolymer is selected from polyamic acid block copolymer, polyimide block copolymer, or polyimide block copolymer. Amic acid-polyimide block copolymer. 10. A liquid crystal alignment agent, characterized in that it comprises the following: A polymer obtained by polymerizing a tetracarboxylic dianhydride compound and a diamine compound; and an organic solvent used to dissolve the polymer; The liquid crystal alignment agent has a T value of 0-1.0%, and the T value is defined by the following steps: mixing the liquid crystal alignment agent with methanol in a weight ratio of 1:6 to obtain a first mixture containing a first solid precipitate; filtering out the first solid precipitate from the first mixture using a 0.2 μm filter; The first solid precipitate was placed in an oven and dried at a temperature of 60° C. for 12 hours to obtain a dried solid with _{a WS} weight value; Mixing the dried solid with N-methyl-2-pyrrolidone at a weight ratio of 1:15 to obtain a solution; mixing the solution with acetone in a weight ratio of 1:6 to obtain a second mixture containing a second solid precipitate; filtering out the second solid precipitate from the second mixture using a 0.2 μm filter to obtain a filtrate; defining the solids content in the filtrate as the W _LS weight value; and The T value is obtained by T=W _LS / _WS . 11. The liquid crystal alignment agent according to claim 10, characterized in that the T value ranges from 0.005% to 0.9%. 12. The liquid crystal alignment agent according to claim 11, characterized in that the T value ranges from 0.01% to 0.8%. 13. The liquid crystal alignment agent according to claim 10, wherein the polymer is selected from polyamic acid, polyimide, or polyimide-based block copolymers. 14. The liquid crystal alignment agent according to claim 13, wherein the polyimide block copolymer is selected from polyamic acid block copolymer, polyimide block copolymer , or polyamic acid-polyimide block copolymer. 15. A liquid crystal alignment film, characterized in that the liquid crystal alignment film is formed by the liquid crystal alignment agent according to claim 10. 16. A liquid crystal display element, characterized in that the liquid crystal display element comprises the liquid crystal alignment film according to claim 15.