CN105482830A - Liquid crystal aligning agent, liquid crystal alignment film and liquid crystal display element - Google Patents

Abstract

The invention provides a liquid crystal alignment agent, a liquid crystal alignment film and a liquid crystal display element. The liquid crystal alignment agent can form a liquid crystal alignment film with good frame glue flatness. The liquid crystal alignment agent includes polymer (A) and solvent (B), wherein polymer (A) is obtained by reacting a mixture including tetracarboxylic dianhydride component (a) and diamine component (b). The tetracarboxylic dianhydride component (a) includes at least one tetracarboxylic dianhydride compound (a-1) represented by formula (1). The diamine component (b) includes at least one diamine compound (b-1) represented by formula (2).

Description

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

technical field

The present invention relates to a liquid crystal alignment agent, a liquid crystal alignment film and a liquid crystal display element, in particular to a liquid crystal alignment agent, a liquid crystal alignment film and a liquid crystal display element capable of forming a liquid crystal alignment film with good sealant flattening properties.

Background technique

In recent years, due to the increasing demand for display quality of liquid crystal displays, the quality and characteristics of liquid crystal alignment agents, such as liquid crystal alignment and ion density, have become more stringent than before. Wherein, when the ion density is too high, problems such as image sticking are likely to occur, resulting in a serious decline in display quality.

Japanese Patent Laid-Open No. 2009-175684 discloses a liquid crystal alignment film with low ion density and a diamine compound containing a piperazine structure used to prepare the liquid crystal alignment film. By using the liquid crystal alignment film made of the diamine compound containing the piperazine structure, the problem of the degradation of the display quality caused by the high ion density of the conventional liquid crystal display can be improved. However, the liquid crystal alignment film has the problem of poor flattening of the frame glue, which reduces the yield rate of subsequent processing.

Therefore, how to solve the problem of poor flatness of the frame glue in the liquid crystal alignment film is one of the active research goals of those skilled in the art.

Contents of the invention

In view of this, the present invention provides a liquid crystal alignment agent, a liquid crystal alignment film, and a liquid crystal display element. The liquid crystal alignment agent can form a liquid crystal alignment film with good sealant flattening properties, and the liquid crystal alignment film can form a liquid crystal display element.

The present invention provides a liquid crystal alignment agent, which includes: a polymer (A) and a solvent (B), wherein the polymer (A) is composed of a tetracarboxylic dianhydride component (a) and a diamine component (b) obtained by the reaction of the mixture. The tetracarboxylic dianhydride component (a) includes at least one tetracarboxylic dianhydride compound (a-1) represented by formula (1). The diamine component (b) includes at least one diamine compound (b-1) represented by formula (2).

Specifically, the tetracarboxylic dianhydride compound (a-1) represented by formula (1) is as follows.

In formula (1), a represents an integer from 2 to 20;

In addition, the diamine compound (b-1) represented by formula (2) is as follows.

In formula (2), W ¹ and W ² each independently represent a single bond, -CO-, -COO- or -OCO-; Y ¹ represents an alkyl group with 1 to 10 carbons, and a fat with 3 to 12 carbons Cyclic group, aromatic group with carbon number from 6 to 12, hydroxyl group, halogen atom, nitro group or cyano group, among them, methylene group (methylene, -CH2- ) can be substituted by an oxygen atom, -CO-, -COO- or -OCO-, and the hydrogen atom of the methylene group can be substituted by at least one halogen atom; Y ² and Y ³ each independently represent a carbon number of 1 to 10 An alkyl group, an alkoxy group with a carbon number of 1 to 10, or a halogen atom; b and c each independently represent an integer greater than or equal to 1, and b+c≧3; d represents an integer from 0 to 5; e and f each independently represent Integer from 0 to 4.

In one embodiment of the present invention, based on 100 moles of the tetracarboxylic dianhydride component (b), the tetracarboxylic dianhydride compound (a-1) is used in an amount of 15 to 100 moles.

In an embodiment of the present invention, based on 100 moles of the total diamine component (b), the usage amount of the diamine compound (b-1) is 5 to 80 moles.

In one embodiment of the present invention, the diamine compound (b-1) includes a diamine compound represented by formula (3).

In formula (3), W ¹ and W ² each independently represent a single bond, -CO-, -COO- or -OCO-; Y ¹ represents an alkyl group with 1 to 10 carbons, and a fat with 3 to 12 carbons Cyclic group, aromatic group with carbon number from 6 to 12, hydroxyl group, halogen atom, nitro group or cyano group, wherein, the methylene group in the alkyl group, alicyclic group and aromatic group can be passed through the oxygen atom, - CO-, -COO- or -OCO-, and the hydrogen atom of the methylene group can be replaced by at least one halogen atom; Y ² and Y ³ each independently represent an alkyl group with a carbon number of 1 to 10, and a carbon number of 1 alkoxy or halogen atom from 10 to 10; b and c each independently represent an integer greater than or equal to 1, and b+c≧3; d represents an integer from 0 to 5; e and f each independently represent an integer from 0 to 4.

In an embodiment of the present invention, the imidization rate of the above-mentioned polymer (A) is 30% to 90%.

The present invention also provides a liquid crystal alignment film formed from the above-mentioned liquid crystal alignment agent.

The present invention further provides a liquid crystal display element, which comprises the above-mentioned liquid crystal alignment film.

Based on the above, in the liquid crystal alignment agent of the present invention, since the mixture of polymers contains a specific tetracarboxylic dianhydride compound and a specific diamine compound, the sealant of the liquid crystal alignment film manufactured using the liquid crystal alignment agent of the present invention It has good flattening property and can further improve the yield rate of subsequent processing.

In order to make the above-mentioned features and advantages of the present invention more comprehensible, the following specific embodiments are described in detail with reference to the accompanying drawings.

Description of drawings

FIG. 1 is a side view of a liquid crystal display element according to an embodiment of the present invention.

Explanation of reference signs:

100: liquid crystal display element;

110: first unit;

112: the first substrate;

114: the first conductive film;

116: a first liquid crystal alignment film;

120: second unit;

122: a second substrate;

124: the second conductive film;

126: a second liquid crystal alignment film;

130: a liquid crystal unit.

detailed description

<Liquid crystal alignment agent>

The present invention provides a liquid crystal alignment agent, which includes a polymer (A) and a solvent (B). In addition, the liquid crystal alignment agent may further include an additive (C) if necessary.

Hereinafter, each component of the liquid crystal alignment agent used in the present invention will be explained in detail.

It is explained here that (meth)acrylic acid is used to represent acrylic acid and/or methacrylic acid, and (meth)acrylate is used to represent acrylate and/or methacrylate; similarly, (meth) Acryloyl represents acryloyl and/or methacryloyl.

Polymer (A)

The polymer (A) is obtained by reacting a mixture including tetracarboxylic dianhydride component (a) and diamine component (b).

Specifically, the polymer (A) includes polyamic acid, polyimide, polyamic acid-polyimide block copolymer, or a combination of these polymers. Wherein, the polyimide series block copolymer comprises polyamic acid block copolymer, polyimide block copolymer, polyamic acid-polyimide block copolymer or the polyamic acid block copolymer combination. Polyamic acid polymers, polyimide polymers and polyamic acid-polyimide block copolymers can all be formed by the reaction of a mixture of tetracarboxylic dianhydride component (a) and diamine component (b). be made of.

Tetracarboxylic dianhydride component (a)

The tetracarboxylic dianhydride component (a) includes at least one tetracarboxylic dianhydride compound (a-1). In addition, the tetracarboxylic dianhydride component (a) may also contain other tetracarboxylic dianhydride compounds (a-2).

Tetracarboxylic dianhydride compound (a-1)

The tetracarboxylic dianhydride compound (a-1) is a compound represented by formula (1).

In formula (1), a represents an integer of 2 to 20.

Specific examples of the tetracarboxylic dianhydride compound (a-1) include ethyleneglycol-bis(trimelliticanhydride), 1,3-propylene glycol bis(trimelliticanhydride) (1,3-propanediol-bis(trimelliticanhydride) )), 1,4-butanediol bis(trimellitic anhydride) (1,4-butanediol-bis(trimelliticanhydride)), 1,5-pentanediol bis(trimellitic anhydride) (1,5-pentanediol-bis(trimelliticanhydride)) , 1,6-hexanediol bis (trimellitic anhydride) (1,6-hexanediol-bis (trimelliticanhydride)), 1,8-octanediol bis (trimellitic anhydride) (1,8-octanediol-bis (trimelliticanhydride)), 1 ,10-decanediol bis(trimellitic anhydride) (1,10-decanediol-bis(trimelliticanhydride)), 1,12-dodecanediol bis(trimellitic anhydride) (1,12-dodecanediol-bis(trimelliticanhydride)), 1,16-hexadecanediol bis(trimellitic anhydride) (1,16-hexadecanediol-bis(trimelliticanhydride)), 1,18-octadecanediol bis(trimellitic anhydride) (1,18-octadecanediol-bis(trimelliticanhydride) ), 1,20-eicosanediol-bis(trimellitic anhydride) (1,20-eicosanediol-bis(trimelliticanhydride)), or a combination of the foregoing.

Specific examples of the tetracarboxylic dianhydride component (a-1) preferably include ethylene glycol bis(trimellitic anhydride), 1,3-propanediol bis(trimellitic anhydride), 1,4-butanediol bis(trimellitic anhydride), 1,6 -Hexanediol bis(trimellitic anhydride), 1,8-octanediol bis(trimellitic anhydride), 1,10-decanediol bis(trimellitic anhydride), 1,18-octadecanediol bis(trimellitic anhydride), 1, 20-Eicosanediol bis(trimellitic anhydride) or a combination of the above compounds.

Based on the total usage of tetracarboxylic dianhydride component (b) as 100 moles, the usage of tetracarboxylic dianhydride compound (a-1) can be from 15 moles to 100 moles, preferably from 20 moles to 90 moles, more preferably 30 moles to 80 moles. When the liquid crystal alignment agent does not use the tetracarboxylic dianhydride compound (a-1), the liquid crystal alignment film has the problem of poor flattening of the frame glue.

Other tetracarboxylic dianhydride compounds (a-2)

Other tetracarboxylic dianhydride compounds (a-2) include aliphatic tetracarboxylic dianhydride compounds, alicyclic tetracarboxylic dianhydride compounds, aromatic tetracarboxylic dianhydride compounds, from formula (I-1) to formula At least one of the tetracarboxylic dianhydride compounds represented by (I-6), or a combination of the above compounds.

Although the specific example of an aliphatic tetracarboxylic dianhydride compound, an alicyclic tetracarboxylic dianhydride compound, and an aromatic tetracarboxylic dianhydride compound is mentioned below, this invention is not limited to these specific examples.

Specific examples of the aliphatic tetracarboxylic dianhydride compound may include, but are not limited to, ethanetetracarboxylic dianhydride, butanetetracarboxylic dianhydride, or combinations of the above compounds.

Specific examples of alicyclic tetracarboxylic dianhydride compounds may include, but are not limited to, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2-dimethyl-1,2,3,4- Cyclobutane tetracarboxylic dianhydride, 1,3-dimethyl-1,2,3,4-cyclobutane tetracarboxylic dianhydride, 1,3-dichloro-1,2,3,4-cyclobutane Butane tetracarboxylic dianhydride, 1,2,3,4-tetramethyl-1,2,3,4-cyclobutane tetracarboxylic dianhydride, 1,2,3,4-cyclopentane tetracarboxylic Acid dianhydride, 1,2,4,5-cyclohexanetetracarboxylic dianhydride, 3,3',4,4'-bicyclohexyltetracarboxylic dianhydride, cis-3,7-dibutylcycloheptyl -1,5-diene-1,2,5,6-tetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentylacetic dianhydride, bicyclo[2.2.2]-oct-7-ene- 2,3,5,6-Tetracarboxylic dianhydride or a combination of the above compounds.

Specific examples of aromatic tetracarboxylic dianhydride compounds may include, but are not limited to, 3,4-dicarboxy-1,2,3,4-tetrahydronaphthalene-1-succinic dianhydride, pyromellitic dianhydride , 3,3',4,4'-benzophenone tetracarboxylic dianhydride, 3,3',4,4'-biphenyl sulfone tetracarboxylic dianhydride, 1,4,5,8-naphthalene tetracarboxylic dianhydride Carboxylic dianhydride, 2,3,6,7-naphthalene tetracarboxylic dianhydride, 3,3'-4,4'-diphenylethanetetracarboxylic dianhydride, 3,3',4,4' -Dimethyldiphenylsilane tetracarboxylic dianhydride, 3,3',4,4'-tetraphenylsilane tetracarboxylic dianhydride, 1,2,3,4-furan tetracarboxylic dianhydride, 4 ,4'-bis(3,4-dicarboxyphenoxy)diphenylsulfide dianhydride, 4,4'-bis(3,4-dicarboxyphenoxy)diphenylsulfone dianhydride, 4,4' -Bis(3,4-dicarboxyphenoxy)diphenylpropanedianhydride (4,4'-bis(3,4-dicarboxyphenoxy)diphenylpropanedianhydride), 3,3',4,4'-perfluoroisopropylene Diphthalic acid dianhydride, 3,3',4,4'-diphenyltetracarboxylic dianhydride, bis(phthalic acid)phenylphosphine oxide dianhydride, p-phenylene-bis(triphenylene phthalic acid) dianhydride, m-phenylene-bis(triphenylphthalic acid) dianhydride, bis(triphenylphthalic acid)-4,4'-diphenylether dianhydride, bis( Triphenylphthalic acid)-4,4'-diphenylmethane dianhydride, 2,2-bis(4-hydroxyphenyl)propane-bis(dehydrated trimellitate), 2,3,4, 5-tetrahydrofuran tetracarboxylic dianhydride, 1,3,3a,4,5,9b-hexahydro-5-(tetrahydro-2,5-dipentoxy-3-furyl)-naphtho[1, 2-c]-furan-1,3-dione {(1,3,3a,4,5,9b-hexahydro-5-(tetrahydro-2,5-dioxo-3-furanyl)naphtho[1,2- c]furan-1,3-dione)}, 1,3,3a,4,5,9b-hexahydro-5-methyl-5-(tetrahydro-2,5-dioxo-3-furan base)-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-methan Base-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-di Ketone, 1,3,3a,4,5,9b-hexahydro-8-methyl-5-(tetrahydro-2,5-dipentoxy-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 -Diketone, 1,3,3a,4,5,9b-hexahydro-5,8-dimethyl-5-(tetrahydro-2,5-dipentoxy-3-furyl)-naphtho [1,2-c]-furan-1,3-dione, 5-(2,5-dioxotetrahydrofuryl)-3-methyl-3-cyclohexene-1,2-dicarboxylic acid An aromatic tetracarboxylic dianhydride compound such as dianhydride, or a combination of the above compounds.

The tetracarboxylic dianhydride compounds represented by formula (I-1) to formula (I-6) are shown below.

In formula (I-5), A ¹ represents a divalent group containing an aromatic ring; r represents an integer from 1 to 2; A ² and A ³ may be the same or different, and may each independently represent a hydrogen atom or an alkyl group. Specific examples of the tetracarboxylic dianhydride compound represented by formula (I-5) include at least one of the compounds represented by formula (I-5-1) to formula (I-5-3).

In formula (I-6), A ⁴ represents a divalent group containing an aromatic ring; A ⁵ and A ⁶ may be the same or different, and each independently represents a hydrogen atom or an alkyl group. The tetracarboxylic dianhydride compound represented by formula (I-6) is preferably a compound represented by formula (I-6-1).

The tetracarboxylic dianhydride component (a) can be used individually or in combination of several types.

Specific examples of other tetracarboxylic dianhydride components (a-2) preferably include 1,2,3,4-cyclobutanetetracarboxylic dianhydride (1,2,3,4-cyclobutanetetracarboxylicaciddianhydride), 1,2, 3,4-cyclopentane tetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentyl acetic acid dianhydride (2,3,5-tricarboxycyclopentylacetic aciddianhydride), 1,2,4,5-cyclohexane tetracarboxylic Acid dianhydride, 3,4-dicarboxy-1,2,3,4-tetrahydronaphthalene-1-succinic dianhydride, pyromellitic dianhydride, 3,3',4,4' - Benzophenone tetracarboxylic dianhydride, 3,3',4,4'-biphenylsulfone tetracarboxylic dianhydride, or a combination of the above compounds.

Based on the total usage of tetracarboxylic dianhydride component (b) as 100 moles, the usage of other tetracarboxylic dianhydride compounds (a-2) can be 0 to 85 moles, preferably 10 to 80 moles, more preferably 20 to 70 moles.

Based on the total moles of diamine component (b) as 100 moles, the usage range of tetracarboxylic dianhydride component (a) is preferably 20 moles to 200 moles; the usage amount of tetracarboxylic dianhydride component (a) The range is more preferably 30 moles to 120 moles.

Diamine component (b)

The diamine component (b) includes at least one diamine compound (b-1). In addition, the diamine component (b) may also include other diamine compounds (b-2).

Diamine compound (b-1)

The diamine compound (b-1) is a compound represented by formula (2).

In formula (2), W ¹ and W ² each independently represent a single bond, -CO-, -COO- or -OCO-.

In formula (2), Y represents an alkyl group with ¹ to 10 carbons, an alicyclic group with 3 to 12 carbons, an aromatic group with 6 to 12 carbons, a hydroxyl group, a halogen atom (fluorine atom, chlorine atom, bromine atom or iodine atom), nitro group or cyano group, wherein, the methylene group in the said alkyl group, said alicyclic group and said aromatic group can be passed through oxygen atom, -CO-, - COO- or -OCO-, and the hydrogen atoms of the methylene group may be replaced by at least one halogen atom.

When Y represents an alkyl group with ¹ to 10 carbons, the alkyl group with 1 to 10 carbons includes, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, 2-butyl, Isobutyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl or n-decyl, etc. When ^Y1 represents an alicyclic hydrocarbon group having 3 to 12 carbon atoms, examples of the alicyclic hydrocarbon group having 3 to 12 carbon atoms include cyclopentyl, cyclohexyl, and the like. When ^Y1 represents an aromatic group having 6 to 12 carbon atoms, examples of the aromatic group having 6 to 12 carbon atoms include phenyl, tolyl, benzyl and the like. Y ¹ preferably represents an alkyl group having a carbon number of 1 to 10, more preferably an alkyl group having a carbon number of 1 to 3, and particularly preferably a methyl group. When a plurality of Y ¹ exists, each of the plurality of Y ¹ may be the same or different.

In formula (2), Y ² and Y ³ each independently represent an alkyl group having 1 to 10 carbons, an alkoxy group having 1 to 10 carbons, or a halogen atom. When Y ² and Y ³ represent an alkyl group having 1 to 10 carbon atoms or a halogen atom, examples of the alkyl group and halogen atom having 1 to 10 carbon atoms are the same as those for Y ¹ above. When Y ² and Y ³ represent an alkoxy group with 1 to 10 carbons, examples of the alkoxy group with 1 to 10 carbons include methoxy, ethoxy, propoxy, butoxy, pentyloxy base, hexyloxy, heptyloxy, octyloxy, nonyloxy or decyloxy, etc. Y ² and Y ³ are preferably an alkyl group having 1 to 3 carbons, an alkoxy group having 1 to 3 carbons, a fluorine atom, a chlorine atom or a bromine atom. When there are a plurality of Y ² and Y ³ , each of the plurality of Y ² and Y ³ may be the same or different.

In formula (2), b and c each independently represent an integer greater than or equal to 1 (where b=c=1 is excluded), and b+c≧3, preferably 3≦b+c≦11. In addition, the combination of b and c is more preferably b=1, c=2 or b=2, c=2.

In formula (2), d represents an integer of 0 to 5, preferably represents an integer of 0 to 2, and more preferably represents an integer of 0 or 1.

In formula (2), e and f each independently represent an integer of 0 to 4, preferably an integer of 0 to 2, and more preferably an integer of 0 or 1.

It is worth noting that the position of each aminogroup (aminogroup) bonded to the benzene ring can be in the ortho, meta or para position relative to W ¹ and W ² , and the two aminogroups bonded to different benzene rings The amino groups are preferably in the ortho position, both in the para position or in the meta position relative to W ¹ and W ² , particularly preferably in the para position relative to W ¹ and W ² .

Specifically, the diamine compound in which two amine groups bonded to different benzene rings are preferably para-positions to W ¹ and W ² is a diamine compound represented by formula (3).

W ¹ , W ² , Y ¹ , Y ² , Y ³ , b, c, d, e and f in formula (3) and W ¹ , W ² , Y ¹ , Y ² , Y in formula (2) ³ , b, c, d, e and f are synonymous and will not be repeated here.

The diamine compound represented by formula (3) is, for example, formula (2-1), formula (2-4), formula (2-7), formula (2-10), formula (2-11), Diamine compounds represented by formula (2-13) to formula (2-18).

Specific examples of the diamine compound (b-1) include at least one of the diamine compounds represented by formula (2-1) to formula (2-18).

Based on 100 moles of the total diamine component (b), the diamine compound (b-1) may be used in an amount of 5 to 80 moles, preferably 10 to 75 moles, more preferably 15 to 70 moles. When the liquid crystal alignment agent does not use the diamine compound (b-1), the liquid crystal alignment film has the problem of poor flattening of the frame glue.

When the diamine compound (b-1) includes the diamine compound represented by formula (3), the sealant leveling property of the liquid crystal alignment film produced by the liquid crystal alignment agent can be further improved.

Other diamine compounds (b-2)

Other diamine compounds (b-2) include aliphatic diamine compounds, alicyclic diamine compounds, aromatic diamine compounds, diamine compounds having structural formulas (II-1) to (II-30), or combinations thereof .

Specific examples of aliphatic diamine compounds include, but are not limited to, 1,2-diaminoethane, 1,3-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane , 1,6-diaminohexane, 1,7-diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane, 1,10-diaminodecane , 4,4'-diaminoheptane, 1,3-diamino-2,2-dimethylpropane, 1,6-diamino-2,5-dimethylhexane, 1,7 -Diamino-2,5-dimethylheptane, 1,7-diamino-4,4-dimethylheptane, 1,7-diamino-3-methylheptane, 1, 9-Diamino-5-methylnonane, 2,11-diaminododecane, 1,12-diaminooctadecane, 1,2-bis(3-aminopropoxy)ethane Alkanes, or combinations of the above compounds.

Specific examples of alicyclic diamine compounds include, but are not limited to, 4,4'-diaminodicyclohexylmethane, 4,4'-diamino-3,3'-dimethyldicyclohexylamine, 1, 3-Diaminocyclohexane, 1,4-diaminocyclohexane, isophoronediamine, tetrahydrodicyclopentadienediamine, tricyclo[6.2.1.0 ^2,7 ]-undeca Carbenedimethyldiamine, 4,4'-methylenebis(cyclohexylamine), or a combination of the above compounds.

Specific examples of aromatic diamine compounds include, but are not limited to, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylethane, 4,4'-diaminodiphenyl Sulfone, 4,4'-diaminobenzanilide, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 1,5-diaminonaphthalene, 5-amino-1-(4'-aminophenyl)-1,3,3-trimethylhydroindene, 6-amino-1-(4'-aminophenyl)-1,3, 3-trimethylhydroindene, hexahydro-4,7-methyleneindenylidene dimethylenediamine, 3,3'-diaminobenzophenone, 3,4'-diaminodi Benzophenone, 4,4'-diaminobenzophenone, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 2,2-bis[4-(4- Aminophenoxy)phenyl]hexafluoropropane, 2,2-bis(4-aminophenyl)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, 9,10-bis(4-aminophenyl)anthracene [9,10-bis(4-aminophenyl)anthracene], 2,7 -diaminofluorene, 9,9-bis(4-aminophenyl)fluorene, 4,4'-methylene-bis(2-chloroaniline), 4,4'-(p-phenylene iso Propylene)bisaniline, 4,4'-(m-phenylene isopropylidene)bisaniline, 2,2'-bis[4-(4-amino-2-trifluoromethylphenoxy )phenyl]hexafluoropropane, 4,4'-bis[(4-amino-2-trifluoromethyl)phenoxy]-octafluorobiphenyl, 5-[4-(4-n-pentyl Cyclohexyl)cyclohexyl]phenyl-methylene-1,3-diaminobenzene {5-[4-(4-n-pentylcyclohexyl)cyclohexyl]phenylmethylene-1,3-diaminobenzene}, 1,1-bis [4-(4-aminophenoxy)phenyl]-4-(4-ethylphenyl)cyclohexane{1,1-bis[4-(4-aminophenoxy)phenyl]-4-(4 -ethylphenyl)cyclohexane}, or a combination of the above compounds.

Diamine compounds having structural formulas (II-1) to (II-30) are shown below.

In formula (II-1), B ¹ represents -O-, B represents a group having a steroid (steroid) skeleton, a trifluoromethyl group, a fluorine group, an alkyl group with a carbon number of ² to 30, or a nitrogen-containing ring derived from pyridine, pyrimidine, triazine, piperidine or piperazine, etc. A monovalent group with a similar structure.

Specific examples of compounds represented by formula (II-1) include, but are not limited to, ethyl 2,4-diaminophenylformate (2,4-diaminophenylformate), ethyl 3,5-diaminophenylformate ( 3,5-diaminophenylethylformate), 2,4-diaminophenylpropylformate (2,4-diaminophenylpropylformate), 3,5-diaminophenylpropylformate (3,5-diaminophenylpropylformate), 1-deca Dialkoxy-2,4-diaminobenzene (1-dodecoxy-2,4-diaminobenzene), 1-hexadecoxy-2,4-diaminobenzene (1-hexadecoxy-2,4- diaminobenzene), 1-octadecyloxy-2,4-diaminobenzene (1-octadecoxy-2,4-diaminobenzene), represented by formula (II-1-1) to formula (II-1-6) At least one of the compounds, or a combination of the above compounds.

Compounds represented by formula (II-1-1) to formula (II-1-6) are shown below.

In formula (II- ² ), B1 is the same as B1 in formula (II ^{- 1} ), and ^B3 and B4 each independently represent a divalent alicyclic ring, a divalent aromatic ring or a divalent heterocyclic group; B5 represents an alkyl group with a carbon number of ³ to 18, an alkoxy group with a carbon number of 3 to 18, a fluoroalkyl group with a carbon number of 1 to 5, a fluoroalkoxy group with a carbon number of 1 to 5, a cyano group or halogen atom.

Specific examples of the compound represented by formula (II-2) include at least one of the compounds represented by formula (II-2-1) to formula (II-2-13). Specifically, compounds represented by formula (II-2-1) to formula (II-2-13) are shown below.

In formula (II-2-10) to formula (II-2-13), s represents an integer of 3 to 12.

In formula (II- ³ ), B6 each independently represents a hydrogen atom, an acyl group with 1 to 5 carbons, an alkyl group with 1 to 5 carbons, an alkoxy group with 1 to 5 carbons, or a halogen atom, and B ⁶ in each repeating unit may be the same or different; u represents an integer of 1 to 3.

Specific examples of compounds represented by formula (II-3) include when u is 1: p-diaminobenzene, m-diaminobenzene, o-diaminotoluene, or 2,5-diaminotoluene, etc.; when u When it is 2: 4,4'-diaminobiphenyl, 2,2'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dimethyl-4,4'-di Aminobiphenyl, 3,3'-dimethoxy-4,4'-diaminobiphenyl, 2,2'-dichloro-4,4'-diaminobiphenyl, 3,3'- Dichloro-4,4'-diaminobiphenyl, 2,2',5,5'-tetrachloro-4,4'-diaminobiphenyl, 2,2'-dichloro-4,4' -Diamino-5,5'-dimethoxybiphenyl or 4,4'-diamino-2,2'-bis(trifluoromethyl)biphenyl, etc.; or when u is 3: 1 , 4-bis(4'-aminophenyl)benzene and so on.

Specific examples of the compound represented by formula (II-3) preferably include p-diaminobenzene, 2,5-diaminotoluene, 4,4'-diaminobiphenyl, 3,3'-dimethoxy - 4,4'-diaminobiphenyl, 1,4-bis(4'-aminophenyl)benzene or a combination of the above compounds.

In formula (II-4), v represents an integer of 2 to 12.

In formula (II-5), w represents an integer of 1 to 5. The compound represented by formula (II-5) is preferably 4,4'-diamino-diphenylsulfide.

In formula (II-6), B ⁷ and B ⁹ each independently represent a divalent organic group, and B ⁷ and B ⁹ can be the same or different; B ⁸ represents a group derived from pyridine, pyrimidine, triazine, piperidine or piperidine A divalent group with a ring structure containing a nitrogen atom such as oxazine.

In formula (II-7), B ¹⁰ , B ¹¹ , B ¹² and B ¹³ each independently represent a hydrocarbon group with a carbon number of 1 to 12, and B ¹⁰ , B ¹¹ , B ¹² and B ¹³ may be the same or different; X1 Each independently represents an integer of 1 to 3; X2 represents an integer of 1 to 20.

In formula (II-8), B ¹⁴ represents an oxygen atom or a cyclohexylene group; B ¹⁵ represents a methylene group; B ¹⁶ represents a phenylene group or a cyclohexylene group; B ¹⁷ represents a hydrogen atom or a heptyl group.

Specific examples of the compound represented by formula (II-8) include a compound represented by formula (II-8-1), a compound represented by formula (II-8-2), or a combination of the above compounds.

Compounds represented by formula (II-9) to formula (II-30) are shown below.

In formula (II-17) to formula (II-25), B ¹⁸ preferably represents an alkyl group with a carbon number of 1 to 10 or an alkoxy group with a carbon number of 1 to 10; B ¹⁹ preferably represents a hydrogen atom, and the carbon number is An alkyl group of 1 to 10 or an alkoxy group having a carbon number of 1 to 10.

The above-mentioned other diamine compound (b-2) can be used individually or in combination of several types.

Specific examples of other diamine compounds (b-2) preferably include, but are not limited to, 1,2-diaminoethane, 4,4'-diaminodicyclohexylmethane, 4,4'-diaminodiphenyl Methane, 4,4'-diaminodiphenyl ether, 5-[4-(4-n-pentylcyclohexyl)cyclohexyl]phenylmethylene-1,3-diaminobenzene, 1 , 1-bis[4-(4-aminophenoxy)phenyl]-4-(4-ethylphenyl)cyclohexane, ethyl 2,4-diaminophenylcarboxylate, by formula ( The compound represented by II-1-1), the compound represented by formula (II-1-2), the compound represented by formula (II-1-5), the compound represented by formula (II-2-1), the compound represented by The compound represented by formula (II-2-11), p-diaminobenzene, m-diaminobenzene, ortho-diaminobenzene, the compound represented by formula (II-8-1), the compound represented by formula (II-26) The compound represented by, the compound represented by formula (II-29), or a combination of the above-mentioned compounds.

Based on the total amount of diamine component (b) being 100 moles, the amount of other diamine compounds (b-2) may be 20 to 95 moles, preferably 25 to 90 moles, more preferably 30 to 85 moles.

Process for preparing polymer (A)

The polymer (A) may include at least one of polyamic acid and polyimide. In addition, the polymer (A) may further include a polyimide-based block copolymer. The preparation methods of the above-mentioned various polymers are further described below.

Method for preparing polyamic acid

The method for preparing polyamic acid is to first dissolve the mixture in a solvent, wherein the mixture includes tetracarboxylic dianhydride component (a) and diamine component (b), and carry out polycondensation at a temperature of 0°C to 100°C reaction. After reacting for 1 hour to 24 hours, the reaction solution is distilled under reduced pressure with an evaporator to obtain polyamic acid. Alternatively, the reaction solution is poured into a large amount of poor solvent to obtain a precipitate. Then, the precipitate is dried under reduced pressure to obtain polyamic acid.

The solvent used in the polycondensation reaction may be the same as or different from the solvent in the liquid crystal alignment agent described below, and the solvent used in the polycondensation reaction is not particularly limited as long as it can dissolve the reactants and products. Solvents preferably include but are not limited to (1) aprotic polar solvents, such as: N-methyl-2-pyrrolidinone (N-methyl-2-pyrrolidinone; NMP), N,N-dimethylacetamide, N, Aprotic polar solvents such as N-dimethylformamide, dimethylsulfoxide, γ-butyrolactone, tetramethylurea, or hexamethylphosphoric triamine; or (2) phenolic solvents, such as: Phenolic solvents such as m-cresol, xylenol, phenol, or halogenated phenols. The solvent used in the polycondensation reaction is preferably used in an amount of 200 to 2000 parts by weight, and more preferably 300 to 1800 parts by weight, based on 100 parts by weight in total of the mixture.

It should be noted that in the polycondensation reaction, the solvent can be used together with an appropriate amount of poor solvent, and the poor solvent will not cause the precipitation of polyamic acid. Poor solvents can be used alone or in combination, and they include but are not limited to (1) alcohols, such as: methanol, ethanol, isopropanol, cyclohexanol, ethylene glycol, propylene glycol, 1,4- Alcohols such as butylene glycol or triethylene glycol; (2) ketones, such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, etc.; (3) esters, For example: esters of methyl acetate, ethyl acetate, butyl acetate, diethyl oxalate, diethyl malonate or ethylene glycol ethyl ether acetate; (4) ethers, such as: diethyl ether, ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol n-propyl ether, ethylene glycol isopropyl ether, ethylene glycol n-butyl ether, ethylene glycol dimethyl ether, or diethylene glycol Ethers such as dimethyl ether; (5) halogenated hydrocarbons, such as dichloromethane, 1,2-dichloroethane, 1,4-dichlorobutane, trichloroethane, chlorobenzene or o- Halogenated hydrocarbons such as dichlorobenzene; or (6) hydrocarbons, such as tetrahydrofuran, hexane, heptane, octane, benzene, toluene or xylene or any combination of the above solvents. The amount of the poor solvent used is preferably 0 to 60 parts by weight, and more preferably 0 to 50 parts by weight, based on 100 parts by weight of the diamine component (b).

Method for preparing polyimide

The method for preparing polyimide is obtained by heating the polyamic acid prepared by the above method for preparing polyamic acid in the presence of a dehydrating agent and a catalyst. During the heating process, the amic acid functional group in the polyamic acid can be transformed into an imide functional group through a dehydration ring-closure reaction (ie, imidization).

The solvent used in the dehydration ring-closing reaction can be the same as the solvent (B) in the liquid crystal alignment agent, so it will not be repeated here. Based on 100 parts by weight of the polyamic acid, the amount of the solvent used in the dehydration ring-closure reaction is preferably 200 to 2000 parts by weight, and more preferably 300 to 1800 parts by weight.

In order to obtain a better degree of imidization of the polyamic acid, the operating temperature of the dehydration ring closure reaction is preferably 40°C to 200°C, more preferably 40°C to 150°C. If the operating temperature of the dehydration ring-closing reaction is lower than 40° C., the imidization reaction will not be complete, and the degree of imidization of the polyamic acid will be reduced. However, if the operating temperature of the dehydration ring-closing reaction is higher than 200° C., the weight average molecular weight of the obtained polyimide is low.

The dehydrating agent used in the dehydration ring-closing reaction can be selected from acid anhydride compounds, for example, acid anhydride compounds such as acetic anhydride, propionic anhydride or trifluoroacetic anhydride. Based on 1 mole of the polyamic acid, the amount of the dehydrating agent is 0.01 mole to 20 mole. The catalyst used in the dehydration ring-closing reaction can be selected from (1) pyridine compounds, such as: pyridine compounds such as pyridine, collidine or lutidine; (2) tertiary amine compounds, such as: triethyl Tertiary amine compounds such as base amines. Based on 1 mole of the dehydrating agent, the catalyst may be used in an amount of 0.5 moles to 10 moles.

The imidization rate of the polymer (A) may be 30% to 90%, preferably 35% to 85%, and more preferably 40% to 80%. When the imidization rate of the polymer (A) in the liquid crystal alignment agent is within the above-mentioned range, the flatness of the sealant of the liquid crystal alignment film can be further improved.

Method for preparing polyimide-based block copolymers

Polyimide block copolymer is selected from polyamic acid block copolymer, polyimide block copolymer, polyamic acid-polyimide block copolymer or the above-mentioned polymer random combination.

The method for preparing polyimide-based block copolymers is preferably firstly dissolving the starting material in a solvent, and performing a polycondensation reaction, wherein the starting material includes at least one polyamic acid and/or at least one polyimide amine, and may further include a carboxylic anhydride component and a diamine component.

The carboxylic acid anhydride component and the diamine component in the starter can be the same as the tetracarboxylic dianhydride component (a) and the diamine component (b) used in the method for preparing polyamic acid, and used for polyamic acid The solvent in the condensation reaction may be the same as the solvent in the liquid crystal alignment agent described below, which will not be repeated here.

The solvent used in the polycondensation reaction is preferably used in an amount of 200 to 2000 parts by weight, and more preferably 300 to 1800 parts by weight, based on 100 parts by weight of the starting material. The operating temperature of the polycondensation reaction is preferably 0°C to 200°C, and more preferably 0°C to 100°C.

The starting material preferably includes but is not limited to (1) two kinds of polyamic acids with different terminal groups and different structures; (2) two kinds of polyimides with different terminal groups and different structures; (3) two kinds of polyimides with different terminal groups and different structures; Different and structurally different polyamic acid and polyimide; (4) polyamic acid, carboxylic anhydride component and diamine component, wherein, at least one of the carboxylic anhydride component and diamine component and The structure of the carboxylic anhydride component and the diamine component used to form polyamic acid is different; (5) polyimide, carboxylic anhydride component and diamine component, wherein, the carboxylic anhydride component and the diamine component At least one of them is different from the structure of the carboxylic anhydride component and the diamine component used to form the polyimide; (6) polyamic acid, polyimide, carboxylic anhydride component and diamine component, Wherein, at least one of the carboxylic anhydride component and the diamine component is different from the structure of the carboxylic anhydride component and the diamine component used to form polyamic acid or polyimide; (7) the two structures are similar Different polyamic acid, carboxylic acid anhydride components and diamine components; (8) two polyimides with different structures, carboxylic anhydride components and diamine components; (9) two kinds of terminal groups are acid anhydride groups and polyamic acid and diamine components with different structures; (10) two kinds of polyamic acid and carboxylic anhydride components whose terminal groups are amine groups and have different structures; (11) two kinds of terminal groups are anhydride groups and have structures different polyimide and diamine components; or (12) two kinds of polyimide and carboxylic anhydride components whose terminal groups are amine groups and have different structures.

Polyamic acid, polyimide, and polyimide-based block copolymers are preferably end-modified polymers whose molecular weight has been adjusted first, as long as they do not affect the efficacy of the present invention. By using terminal-modified polymers, the coating performance of the liquid crystal alignment agent can be improved. The method of preparing the end-modified polymer can be obtained by adding a monofunctional compound while the polyamic acid undergoes polycondensation reaction.

Specific examples of monofunctional compounds include but are not limited to (1) monobasic acid anhydrides, such as: maleic anhydride, phthalic anhydride, itaconic anhydride, n-decyl succinic anhydride, n-dodecyl succinic anhydride, n-tetradecyl anhydride, Monobasic acid anhydrides such as alkyl succinic anhydride or n-hexadecyl succinic anhydride; (2) Monoamine compounds, such as: 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, Monoamine compounds such as n-octadecylamine or n-eicosylamine; or (3) monoisocyanate compounds, such as monoisocyanate compounds such as phenyl isocyanate or naphthyl isocyanate.

The polymer (A) of the present invention has a polystyrene-equivalent weight-average molecular weight measured by Gel Permeation Chromatography (GPC) of 2,000 to 200,000, preferably 3,000 to 100,000, more preferably 4,000 to 50,000.

solvent (B)

The solvent used in the liquid crystal alignment agent of the present invention is not particularly limited, as long as it can dissolve the polymer (A) and other arbitrary components and does not react with it, it is preferably the same as that used in the aforementioned synthesis of polyamic acid As a solvent, at the same time, the poor solvent used when synthesizing this polyamic acid can also be used together.

Specific examples of solvent (B) include, but are not limited to, N-methyl-2-pyrrolidone (N-methyl-2-pyrrolidone, NMP), γ-butyrolactone, γ-butyrolactam, 4-hydroxyl-4-methyl -2-pentanone, ethylene glycol monomethyl ether, butyl lactate, butyl acetate, methyl methoxy propionate, ethyl ethoxy propionate, ethylene glycol methyl ether, ethylene glycol ethyl Ethyl ether, ethylene glycol n-propyl ether, ethylene glycol isopropyl ether, ethylene glycol n-butyl ether (ethyleneglycoln-butylether), ethylene glycol dimethyl ether, ethylene glycol ethyl ether acetate, diethylene glycol Glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol Monoethyl ether acetate or N,N-dimethylformamide or N,N-dimethylacetamide (N,N-dimethylacetamide), etc. The solvent (B) can be used individually or in combination of multiple types.

Based on 100 parts by weight of the polymer (A), the solvent (B) is used in an amount of 800 to 4000 parts by weight, preferably 900 to 3500 parts by weight, and more preferably 1000 to 3000 parts by weight.

Additive (C)

In the range that does not affect the effectiveness of the present invention, the liquid crystal alignment agent can optionally add additives (C), wherein the additives (C) include compounds with at least two epoxy groups, silane compounds with functional groups, or a combination thereof.

Compounds having at least two epoxy groups include, but are not limited to, 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, 2,2-Di Bromoneopentyl glycol diglycidyl ether, 1,3,5,6-tetraepoxypropyl-2,4-hexanediol, N,N,N',N'-tetraepoxypropyl- m-Xylylenediamine, 1,3-bis(N,N-diepoxypropylaminomethyl)cyclohexane, N,N,N',N'-tetraepoxypropyl-4,4 '-Diaminodiphenylmethane, N,N-epoxypropyl-p-glycidoxyaniline, 3-(N-allyl-N-epoxypropyl)aminopropyltrimethoxy silane, 3-(N,N-diecidylpropyl)aminopropyltrimethoxysilane, or a combination of the above compounds.

The compound which has at least two epoxy groups mentioned above can be used individually or in combination of several types.

Based on 100 parts by weight of the polymer (A), the compound having at least two epoxy groups may be used in an amount of 0 to 40 parts by weight, and preferably 0.1 to 30 parts by weight.

Specific examples of silane compounds having functional groups include, but are not limited to, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 2-aminopropyltrimethoxysilane, 2-aminopropyltrimethoxysilane, -Aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropyl Methyldimethoxysilane, 3-ureidopropyltrimethoxysilane (3-ureidopropyltrimethoxysilane), 3-ureidopropyltriethoxysilane, N-ethoxycarbonyl-3-aminopropyltrimethoxysilane Oxysilane, N-ethoxycarbonyl-3-aminopropyltriethoxysilane, N-triethoxysilylpropyltriethylenetriamine, N-trimethoxysilylpropyltriethylenetriamine Amine, 10-trimethoxysilyl-1,4,7-triazidecane, 10-triethoxysilyl-1,4,7-triazidecane, 9-trimethoxysilyl-3 , 6-diacrinonyl acetate, 9-triethoxysilyl-3,6-diacrinonyl acetate, N-benzyl-3-aminopropyltrimethoxysilane, N-benzene Methyl-3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltriethoxysilane, N- Bis(oxyethylene)-3-aminopropyltrimethoxysilane, N-bis(oxyethylene)-3-aminopropyltriethoxysilane, or a combination of the foregoing.

Additives (C) can be used alone or in combination.

Based on 100 parts by weight of the polymer (A), the silane compound having a functional group may be used in an amount of 0 to 10 parts by weight, and preferably 0.5 to 10 parts by weight.

The additive (C) is preferably used in an amount of 0.5 to 50 parts by weight, and more preferably 1 to 45 parts by weight, based on 100 parts by weight of the total polymer (A).

<Preparation method of liquid crystal alignment agent>

The preparation method of the liquid crystal alignment agent of the present invention is not particularly limited, and can be prepared by a general mixing method. For example, first add the solvent (B) to the polymer (A) prepared in the above manner at a temperature of 0°C to 200°C, and optionally add the additive (C), and finally use a stirring device to continuously Stir until dissolved. In addition, it is more preferable to add the solvent (B) at a temperature of 20°C to 60°C.

<Formation Method of Liquid Crystal Alignment Film>

The method for forming the liquid crystal alignment film of the present invention includes the following steps: first, the liquid crystal alignment agent prepared above is coated with a roll coating method, a spin coating method, a printing method, an ink-jet method, etc. A pre-coat is formed on the surface of the substrate; then, the pre-coat is subjected to pre-bake treatment, post-bake treatment and alignment treatment.

The purpose of the prebaking treatment is to volatilize the organic solvent in the precoat. The operating temperature of the pre-bake treatment is generally 30°C to 120°C, preferably 40°C to 110°C, more preferably 50°C to 100°C. The pre-bake treatment can be performed within any time from 0.1 minute to 30 minutes, preferably from 0.5 minute to 15 minutes, more preferably from 1 minute to 5 minutes. The pre-baking treatment can be performed by a generally known method, for example, heating can be carried out on a heating plate, an oven, a hot air circulation furnace or an infrared furnace.

The purpose of the post-bake treatment is to make the polymer in the pre-coat further undergo dehydration and ring-closure (imidization) reaction. The operating temperature range of the post-bake treatment is generally 150°C to 300°C, preferably 180°C to 280°C, more preferably 200°C to 250°C. The post-bake treatment can be performed within any time from 5 minutes to 240 minutes, preferably from 10 minutes to 100 minutes, more preferably from 20 minutes to 90 minutes. The post-baking process can be performed by the same method as the above-mentioned pre-baking process.

The alignment treatment is not particularly limited. For example, fabrics made of fibers such as nylon, rayon, and cotton can be wound on a drum and rubbed in a certain direction to perform alignment. The above-mentioned alignment processing is well known to those skilled in the art and will not be described in detail here.

<Liquid crystal display element and its manufacturing method>

The liquid crystal display element of the present invention includes a liquid crystal alignment film formed from the liquid crystal alignment agent of the present invention.

The liquid crystal display element of the present invention can be produced as follows.

Prepare two substrates on which the liquid crystal alignment film is formed as described above, arrange liquid crystal between the two substrates, and manufacture a liquid crystal cell. In order to manufacture a liquid crystal cell (cell), the following two methods are mentioned, for example.

The first method: first, two substrates are arranged oppositely across a gap (intercellular gap), so that their respective liquid crystal alignment films face each other; the peripheral parts of the two substrates are bonded together using a sealant; Liquid crystal is injected into the intercellular space divided by the sealant; and the injection hole is closed, so that the liquid crystal cell can be manufactured.

The second method: a method called the One Drop Fill (ODF for short) method. First of all, on a predetermined position on one of the two substrates forming the liquid crystal alignment film, for example, an ultraviolet curable sealing material is coated; liquid crystal is dropped on the surface of the liquid crystal alignment film; then, the other substrate is bonded to make the liquid crystal alignment film facing each other; next, the entire surface of the substrate is irradiated with ultraviolet light to cure the sealant, whereby a liquid crystal cell can be manufactured.

In the case of using any of the above methods, it is desirable to heat the liquid crystal cell to the temperature at which the liquid crystal used is in the isotropic phase, and then slowly cool it to room temperature, thereby removing the flow alignment when filling the liquid crystal.

Then, the liquid crystal display element of the present invention can be obtained by bonding a polarizer to the outer surface of the liquid crystal cell.

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

The polarizing plate used on the outside of the liquid crystal cell can be formed by sandwiching a polarizing film called a "H film" obtained by stretching and aligning polyvinylalcohol and absorbing iodine between cellulose acetate protective films. The polarizing plate or the polarizing plate formed by the H film itself.

FIG. 1 is a side view of a liquid crystal display element according to an embodiment of the present invention. The liquid crystal display element 100 includes a first unit 110 , a second unit 120 and a liquid crystal unit 130 , wherein the second unit 120 is disposed separately from the first unit 110 , and the liquid crystal unit 130 is disposed between the first unit 110 and the second unit 120 .

The first unit 110 includes a first substrate 112 , a first conductive film 114 and a first liquid crystal alignment film 116 , wherein the first conductive film 114 is formed on the surface of the first substrate 112 . In addition, the first conductive film 114 is located between the first substrate 112 and the first liquid crystal alignment film 116 , and the first liquid crystal alignment film 116 is located at one side of the liquid crystal cell 130 .

The second unit 120 includes a second substrate 122 , a second conductive film 124 and a second liquid crystal alignment film 126 , wherein the second conductive film 124 is formed on the surface of the second substrate 122 . In addition, the second conductive film 124 is located between the second substrate 122 and the second liquid crystal alignment film 126 , and the second liquid crystal alignment film 126 is located on the other side of the liquid crystal cell 130 . In other words, the liquid crystal unit 130 is located between the first liquid crystal alignment film 116 and the second liquid crystal alignment film 126 .

The first substrate 112 and the second substrate 122 are selected from transparent materials, etc., wherein the transparent materials include but not limited to alkali-free glass, soda-lime glass, hard glass (Pyles glass), quartz, etc. used in liquid crystal display devices. Glass, polyethylene terephthalate, polybutylene terephthalate, polyethersulfone or polycarbonate, etc.

The materials of the first conductive film 114 and the second conductive film 124 are selected from tin oxide (SnO ₂ ), indium oxide-tin oxide (In ₂ O ₃ —SnO ₂ ), and the like.

The first liquid crystal alignment film 116 and the second liquid crystal alignment film 126 are each the above-mentioned liquid crystal alignment film, and their function is to make the liquid crystal unit 130 form a pre-tilt angle. In addition, when a voltage is applied to the first conductive film 114 and the second conductive film 124 , an electric field may be generated between the first conductive film 114 and the second conductive film 124 . The electric field can drive the liquid crystal unit 130 , thereby changing the arrangement of the liquid crystal molecules in the liquid crystal unit 130 .

The liquid crystals used in the liquid crystal unit 130 can be used alone or in combination, and the liquid crystals include but are not limited to diaminobenzene liquid crystals, pyridazine (pyridazine) liquid crystals, Schiff's base (shiffBase) liquid crystals, azoxy (azoxy ) liquid crystal, biphenyl liquid crystal, phenylcyclohexane liquid crystal, ester liquid crystal, terphenyl, biphenylcyclohexane liquid crystal, pyrimidine ) type liquid crystals, dioxane type liquid crystals, bicyclooctane type liquid crystals or cubane type liquid crystals, etc., and may be added such as cholesterol chloride (cholesterylchloride), cholesterol nonanoic acid Cholesteryl liquid crystals such as cholesterylnonanoate and cholesterylcarbonate, or chiral agents with trade names ^" C-15 _" and ^" CB-15 _" (manufactured by Merck), or Ferroelectric liquid crystals such as p-decyloxybenzylidene-p-amino-2-methylbutyl cinnamate.

Synthesis example of polymer (A)

Synthesis Example A-1-1 to Synthesis Example A-1-5, Synthesis Example A-2-1 to Synthesis Example A-2-10, and Comparative Synthesis Example A-3-1 to Comparison of Polymer (A) are described below. Synthesis example A-3-6:

Synthesis Example A-1-1

A nitrogen inlet, a stirrer, a condenser, and a thermometer were arranged on a four-necked flask with a capacity of 500 milliliters, and nitrogen was introduced. Then, in the four-necked flask, 1.41 g (0.005 mol) of the diamine compound represented by formula (2-2) (abbreviated as b-1-1), 8.92 g (0.045 mol) of 4,4'- Diaminodiphenylmethane (abbreviated as b-2-1) and 80 g of N-methyl-2-pyrolidone (abbreviated as NMP) were stirred at room temperature until dissolved. Then, add 41.03 grams (0.01 moles) of ethylene glycol bis(trimellitic anhydride) (abbreviated as a-1-1), 8.96 grams (0.04 moles) of 2,3,5-tricarboxycyclopentyl acetic acid dianhydride (abbreviated as a-2-1) and 20 grams of NMP, and reacted at room temperature for 2 hours. After the reaction was finished, the reaction solution was poured into 1500 milliliters of water, so that the polymer was precipitated. Then, the obtained polymer was filtered, washed with methanol and filtered three times, placed in a vacuum oven, and dried at a temperature of 60° C. to obtain the polymer (A-1-1).

Synthesis Example A-1-2 to Synthesis Example A-1-5

Synthesis Example A-1-2 to Synthesis Example A-1-5 are the same steps as Synthesis Example A-1-1 to prepare polymer (A-1-2) to polymer (A-1-5) respectively , and its difference lies in: changing the type and usage amount of the monomer (as shown in Table 1).

Synthesis Example A-2-1

A nitrogen inlet, a stirrer, a condenser, and a thermometer were arranged on a four-necked flask with a capacity of 500 milliliters, and nitrogen was introduced. Then, in the four-necked flask, 1.41 g (0.005 mol) of the diamine compound represented by formula (2-2) (abbreviated as b-1-1), 8.92 g (0.045 mol) of 4,4'- Diaminodiphenylmethane (abbreviated as b-2-1) and 80 g of N-methyl-2-pyrolidone (abbreviated as NMP) were stirred at room temperature until dissolved. Then, add 41.03 grams (0.01 moles) of ethylene glycol bis(trimellitic anhydride) (abbreviated as a-1-1), 8.96 grams (0.04 moles) of 2,3,5-tricarboxycyclopentyl acetic acid dianhydride (abbreviated as For a-2-1) and 20 grams of NMP. After reacting at room temperature for 6 hours, 97 g of NMP, 2.55 g of acetic anhydride, and 19.75 g of pyridine were added, the temperature was raised to 60° C., and stirring was continued for 2 hours to carry out imidization reaction. After the reaction was finished, the reaction solution was poured into 1500 milliliters of water, so that the polymer was precipitated. Then, the obtained polymer was filtered, washed with methanol and filtered three times, placed in a vacuum oven, and dried at a temperature of 60° C. to obtain the polymer (A-2-1).

Synthesis Example A-2-2 to Synthesis Example A-2-10

Synthesis Example A-2-2 to Synthesis Example A-2-10 are the same steps as Synthesis Example A-2-1 to prepare polymer (A-2-2) to polymer (A-2-10) respectively , and its difference lies in: changing the type and usage amount of the monomer (as shown in Table 1).

Comparative Synthesis Example A-3-1 to Comparative Synthesis Example A-3-3

Comparing Synthesis Example A-3-1 to Comparison Synthesis Example A-3-3 is to prepare respectively polymer (A-3-1) to polymer (A-3- 3), and its difference is: change the kind of monomer and its usage amount (as shown in Table 2).

Comparative Synthesis Example A-3-4 to Comparative Synthesis Example A-3-6

Comparative synthesis example A-3-4 to comparison synthesis example A-3-6 is to prepare polymer (A-3-4) to polymer (A-3- 6), and its difference is: change the kind of monomer and its usage amount (as shown in Table 2).

The compounds corresponding to the abbreviations in Table 1 and Table 2 are as follows.

Table 2

Examples and Comparative Examples of Liquid Crystal Alignment Agents and Liquid Crystal Alignment Films

Examples 1 to 15 and Comparative Examples 1 to 6 of the liquid crystal alignment agent and the liquid crystal alignment film are described below:

Example 1

a. Liquid crystal alignment agent

Weigh the polymer (A-1-1) of 100 weight parts, the N-methyl-2-pyrrolidone (abbreviated as B-1) of 1200 weight parts and the ethylene glycol n-butyl ether (abbreviated as B-1) of 600 weight parts -2), and at room temperature, continue to stir with a stirring device until dissolved, and the liquid crystal alignment agent of Example 1 can be formed.

b. Liquid crystal alignment film

The above-mentioned liquid crystal alignment agent was coated on two glass substrates with a conductive film made of ITO (indiumtinoxide) with a printing machine (manufactured by Nippon Photo Printing Co., Ltd., model number S15-036) to form a pre-coating layer. Thereafter, the glass substrate was placed on a heating plate, and prebaked at a temperature of 100° C. for 5 minutes. Next, post-baking was performed in a circulating oven at a temperature of 220° C. and a time of 30 minutes. Finally, after the alignment treatment, the glass substrate on which the liquid crystal alignment film of Embodiment 1 is formed can be obtained.

The liquid crystal alignment film of Example 1 was evaluated by the following evaluation methods, and the results are shown in Table 3.

Example 2 to Example 15

The liquid crystal alignment agents and liquid crystal alignment films of Examples 2 to 15 were prepared in the same steps as in Example 1, and the difference is that the types and amounts of ingredients were changed, as shown in Table 3. The liquid crystal alignment films prepared in Examples 2 to 15 were evaluated in the following evaluation methods, and the results are shown in Table 3.

Comparative Example 1 to Comparative Example 6

The liquid crystal alignment agents and liquid crystal alignment films of Comparative Example 1 to Comparative Example 6 were prepared in the same steps as in Example 1, and the difference lies in that the types and usage amounts of the components were changed, as shown in Table 4. The liquid crystal alignment films prepared in Comparative Example 1 to Comparative Example 6 were evaluated by the following evaluation methods, and the results are shown in Table 4.

The compounds corresponding to the abbreviations in Table 3 and Table 4 are as follows.

<Evaluation method>

a. Imidization rate

The imidization rate refers to the ratio of the number of imide rings calculated based on the total amount of the number of amic acid functional groups and the number of imide rings in the polymer, expressed as a percentage.

The detection method is to dry the polymers in the synthesis examples under reduced pressure, and then dissolve them in a suitable deuteration solvent, such as deuterated dimethyl sulfoxide, using tetramethylsilane as a reference substance, from room temperature (eg, 25° C.) to measure the result of 1H-NMR (1H-Nuclearmagneticresonance, 1H-NMR), and then calculate the imidization rate (%) from the mathematical formula (1).

Δ1: The peak area generated by the chemical shift of NH protons around 10ppm;

Δ2: peak area of other protons;

α: The number ratio of one proton of NH group to other protons in the precursor of the polymer (polyamic acid).

b. Flatness of frame glue

Frame glue (type WR723, manufactured by Kyoritsu Chemical Co., Ltd.) was coated on the liquid crystal alignment films of the example and the comparative example, and the shrinkage rate of the glue frame was observed after 10 minutes using a microscope with a power of 50 times. The evaluation criteria for frame laying properties are as follows. The lower the shrinkage rate, the better the flatness of the frame glue of the liquid crystal alignment film.

◎: Shrinkage <10%

○: 10%≦shrinkage rate<15%

△: 5%≦shrinkage rate<20%

╳: Shrinkage rate≧20%

table 3

Table 3 (continued)

Table 4

<Evaluation result>

It can be seen from Table 3 and Table 4 that the liquid crystal alignment film prepared with the liquid crystal alignment agent of polymer (A) prepared by using tetracarboxylic dianhydride compound (a-1) and diamine compound (b-1) at the same time (Example 1 to Example 15) In comparison, the liquid crystal alignment films of Comparative Examples 1 to 13 have the problem of poor flattening properties of the frame glue.

When using the diamine compound represented by formula (3) (i.e. polymer (A-1-3), polymer (A-1-4), polymer (A-2-3), polymer (A-2 -4), polymer (A-2-7), polymer (A-2-8) and polymer (A-2-10)) (embodiment 3,4,8,9,12,13 and 15), the frame glue of the liquid crystal alignment film has better flattening property.

In addition, when the imidization rate is 30% to 90% of the polymer (A) (ie polymer (A-2-4) to polymer (A-2-9)) (Example 9 to Example 14), the frame glue of the liquid crystal alignment film has a better flattening property.

In summary, in the liquid crystal alignment agent of the present invention, the polymer formed by a mixture of a specific tetracarboxylic dianhydride compound and a specific diamine compound is used, so the frame of the liquid crystal alignment film manufactured using the liquid crystal alignment agent of the present invention The adhesive has good leveling property, which can further improve the yield rate of subsequent processing.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than limiting them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: It is still possible to modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the technical solutions of the various embodiments of the present invention. scope.

Claims (7)

1. A liquid crystal alignment agent, characterized in that, comprising: Polymer (A) is obtained by reacting a mixture comprising tetracarboxylic dianhydride component (a) and diamine component (b); and solvent (B), Wherein, the tetracarboxylic dianhydride component (a) includes at least one tetracarboxylic dianhydride compound (a-1) represented by formula (1); the diamine component (b) includes at least one a diamine compound (b-1) represented by formula (2); In formula (1), a represents an integer from 2 to 20; In formula (2), W ¹ and W ² each independently represent a single bond, -CO-, -COO- or -OCO-; Y ¹ represents an alkyl group with 1 to 10 carbons, and a fat with 3 to 12 carbons Cyclic group, aromatic group with carbon number of 6 to 12, hydroxyl group, halogen atom, nitro group or cyano group, wherein, the methylene group in the alkyl group, the alicyclic group and the aromatic group It can be substituted by oxygen atom, -CO-, -COO- or -OCO-, and the hydrogen atom of the methylene group can be substituted by at least one halogen atom; Y ² and Y ³ each independently represent a carbon number of 1 to 10 alkyl, alkoxy or halogen atom with carbon number from 1 to 10; b and c each independently represent an integer greater than or equal to 1, and b+c≧3; d represents an integer from 0 to 5; e and f each independently Represents an integer from 0 to 4. 2. The liquid crystal alignment agent according to claim 1, characterized in that, based on the total usage amount of the tetracarboxylic dianhydride component (b) being 100 moles, the tetracarboxylic dianhydride compound (a-1 ) is used in an amount of 15 to 100 moles. 3. The liquid crystal alignment agent according to claim 1, characterized in that, based on the total usage amount of the diamine component (b) being 100 moles, the usage amount of the diamine compound (b-1) is 5 to 80 moles. 4. The liquid crystal alignment agent according to claim 1, wherein the diamine compound (b-1) comprises a diamine compound represented by formula (3), In formula (3), W ¹ and W ² each independently represent a single bond, -CO-, -COO- or -OCO-; Y ¹ represents an alkyl group with 1 to 10 carbons, and a fat with 3 to 12 carbons Cyclic group, aromatic group with carbon number of 6 to 12, hydroxyl group, halogen atom, nitro group or cyano group, wherein, the methylene group in the alkyl group, the alicyclic group and the aromatic group It can be substituted by oxygen atom, -CO-, -COO- or -OCO-, and the hydrogen atom of the methylene group can be substituted by at least one halogen atom; Y ² and Y ³ each independently represent a carbon number of 1 to 10 alkyl, alkoxy or halogen atom with carbon number from 1 to 10; b and c each independently represent an integer greater than or equal to 1, and b+c≧3; d represents an integer from 0 to 5; e and f each independently Represents an integer from 0 to 4. 5. The liquid crystal alignment agent according to claim 1, characterized in that, the imidization rate of the polymer (A) is 30% to 90%. 6. A liquid crystal alignment film, characterized in that it is formed from the liquid crystal alignment agent according to any one of claims 1 to 5. 7. A liquid crystal display element, characterized by comprising the liquid crystal alignment film as claimed in claim 6.