TWI666232B - Liquid crystal alignment agent and production method thereof, liquid crystal alignment film and production method thereof, and liquid crystal display element - Google Patents

Abstract

The invention provides a liquid crystal alignment agent with excellent environmental resistance and a method for manufacturing the same, a liquid crystal alignment film and a method for manufacturing the same, and a liquid crystal display element having the liquid crystal alignment film. The liquid crystal alignment agent includes a polymer (A) and a solvent (B). The polymer (A) is selected from a polyacrylic acid polymer, a polyimide polymer, a polyimide-based block copolymer, or any combination of the above polymers, and includes a formula (b1-0) The unit. Formula (b1-0)

Description

Liquid crystal alignment agent and manufacturing method thereof, liquid crystal alignment film and manufacturing method thereof, and liquid crystal display element

The present invention relates to a liquid crystal alignment agent and a method for manufacturing the same, a liquid crystal alignment film and a method for manufacturing the same, and a liquid crystal display element, and more particularly, to a liquid crystal alignment agent with excellent environmental resistance, a method for manufacturing the same, and the liquid crystal alignment agent A liquid crystal alignment film, a method for manufacturing the same, and a liquid crystal display element having the liquid crystal alignment film.

In recent years, as consumers' requirements for the wide viewing angle characteristics of liquid crystal displays have increased year by year, the requirements for the electrical characteristics or display characteristics of liquid crystal display elements with wide viewing angles have become more stringent than in the past. Among them, the vertical alignment type (Vertical (Alignment) liquid crystal display elements are the most widely studied. In order to have the above-mentioned characteristics, the liquid crystal alignment film has become one of the important research objects for improving the characteristics of the vertical alignment type liquid crystal display element.

The liquid crystal alignment film in the vertical alignment type liquid crystal display element is mainly used to make the liquid crystal molecules have a regular arrangement and to make the liquid crystal molecules have a large tilt angle without providing an electric field, and the liquid crystal alignment film is usually formed by A liquid crystal alignment agent containing a polymer material such as polyamic acid polymer and polyimide polymer is coated on a substrate surface, and is formed after heat treatment and alignment treatment.

Japanese Patent Application Laid-Open No. 2002-162630 discloses a polyamino acid polymer used as a liquid crystal alignment film for a vertical alignment type liquid crystal display element, which is a diamine compound represented by formula (I-1) and a dicarboxylic acid Anhydride compounds are obtained through polymerization. Formula (I-1) In formula (I-1), T, U, and V are each independently a phenyl group or a cyclohexane group, and any -H on the phenyl group or the cyclohexane group may have a carbon number of 1 Alkyl to 3, alkyl having 1 to 3 carbons and substituted with -F, -F, -Cl or -CN. a and b are each independently an integer of 0 to 2, c is an integer of 0 to 5, and R is -H, -F, -Cl, -CN, or a monovalent organic group. When a or b is 2, two U or two V may be the same or different.

On the other hand, International Publication No. 2009-093704 discloses a liquid crystal alignment treatment agent, a polyamic acid obtained by reacting a diamine compound represented by formula (I-2) with a tetracarboxylic dianhydride, or a polyfluorene Polyamidoimide obtained by dehydration ring closure of amino acid. Formula (I-2) In Formula (I-2), W ₁ is at least one selected from the group consisting of -O-, -NQ-, -CONQ-, -NQCO-, -CH ₂ O-, and -OCO-. A divalent organic group, Q is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, W ₂ is a single bond or is selected from the group consisting of an aliphatic hydrocarbon group having 1 to 20 carbon atoms, a non-aromatic cyclic hydrocarbon group, and an aromatic hydrocarbon group Group of at least one divalent organic group, W ₃ is a single bond or is selected from the group consisting of -O-, -NQ-, -CONQ-, -NQCO-, -COO-, -OCO-, and -O (CH ₂ ) _i- (i is an integer of 1 to 5) at least one divalent organic group of the group consisting of W ₄ is a nitrogen-containing aromatic heterocyclic ring, and h is an integer of 1 to 4;

In addition, International Publication No. 2011-155576 discloses a liquid crystal alignment treatment agent containing a polyimide precursor selected from a diamine compound having a cyclic carbonate group side chain represented by formula (I-3) as a raw material, and At least one polymer in which the polyimide precursor is polyimide after polyimidization. Formula (I-3) In formula (I-3), Z ₁ is -O-, -NH-, -N (CH ₃ )-, -CONH-, -NHCO-, -CH ₂ O-, -COO- , -OCO -, - CON (CH 3) - or _{N (CH 3) CO-, Z} 2 is a C 1-5 alkylene group, Z ₃ is a structure of formula (I-4) shown in n is an integer from 1 to 4. Formula (I-4)

The liquid crystal alignment film can form liquid crystals with a high pretilt angle close to 90 ° to achieve good liquid crystal alignment. However, the liquid crystal alignment agent has poor environmental resistance and is unacceptable to the industry.

Therefore, how to provide a liquid crystal alignment agent with good environmental resistance is a problem that those skilled in the art want to solve. [Patent Literature]

[Patent Literature 1] Japanese Patent Laid-Open No. 2002-162630 [Patent Literature 2] International Publication No. 2009-093704 [Patent Literature 3] International Publication No. 2011-155576

In view of this, the present invention provides a liquid crystal alignment agent for a liquid crystal display element. A liquid crystal alignment film prepared using the liquid crystal alignment agent can improve the problem of poor environmental resistance.

The invention provides a liquid crystal alignment agent, which includes a polymer (A) and a solvent (B). Among them, the polymer (A) is selected from a polyamic acid polymer, a polyimide polymer, a polyimide-based block copolymer, or any combination of the above polymers. The polymer (A) contains a unit represented by the formula (b1-0): Formula (b1-0) In formula (b1-0), R ^a and R ^b each independently represent a single bond or a straight or branched chain alkyl group having 1 to 10 carbon atoms; Y is -O-, -COO-, -CONR ^c- , or -NR ^c- ; R ^c is H or a linear or branched alkyl group having 1 to 3 carbons; Cy is an alicyclic heterocyclic ring or an alicyclic heterocyclic ring containing a substituent; * Is the bond; the substituent of the above-mentioned alicyclic heterocyclic ring containing a substituent is a straight or branched alkyl group having 1 to 6 carbon atoms, an aromatic ring or an alicyclic ring.

In one embodiment of the present invention, the polymer (A) includes a carboxylic acid group.

In one embodiment of the present invention, the fluorene imidization rate of the polymer (A) is 30 to 90%.

The present invention also provides a liquid crystal alignment film formed using the liquid crystal alignment agent as described above.

The present invention also provides a liquid crystal display element including the liquid crystal alignment film as described above.

The invention further provides a method for manufacturing a liquid crystal alignment agent, which comprises mixing a polymer (A) and a solvent (B); wherein the polymer (A) comprises a tetracarboxylic dianhydride component (a) and a diamine It is obtained by reacting the mixture of component (b). The diamine component (b) includes at least one diamine compound (b1) represented by the formula (b1-1): Formula (b1-1) In formula (b1-1), R ^a and R ^b each independently represents a single bond or a linear or branched alkyl group having 1 to 10 carbon atoms; Y is -O-, -COO-, -CONR ^c -or -NR ^c- ; R ^c is H or a linear or branched alkyl group having 1 to 3 carbon atoms; Cy is an alicyclic heterocyclic ring or an alicyclic heterocyclic ring containing a substituent; the above-mentioned The substituent of the alicyclic heterocyclic ring of the substituent is a linear or branched alkyl group having 1 to 6 carbon atoms, an aromatic ring or an alicyclic ring.

In one embodiment of the present invention, the total mole number of the diamine component (b) is 100 moles, and the amount of the diamine compound (b1) represented by the formula (b1-1) is 5 to 35. Mor.

In an embodiment of the present invention, the diamine component (b) further includes a diamine compound (b2) having a carboxylic acid group and represented by the formula (b2-1): Formula (b2-1) In formula (b2-1), X represents an organic group having an aromatic ring having 6 to 30 carbon atoms; z1 represents an integer of 1 to 4.

In one embodiment of the present invention, the diamine compound (b2) having a carboxylic acid group and represented by the formula (b2-1) is selected from the group consisting of the formulae (b2-2) to (b2-6). At least one of the groups of compounds: Formula (b2-2) (B2-3) (B2-4) Formula (b2-5) Formula (b2-6) In formulas (b2-2) to (b2-6), X ¹ and X ³ each independently represent a single bond, -CH _2- , -C ₂ H _4- , -C (CH ₃ ) _2- , -CF _2- , -C (CF ₃ ) _2- , -O-, -CO-, -NH-, -N (CH ₃ )-, -CONH-, -NHCO-, -CH ₂ O- , -OCH _2- , -COO-, -OCO-, -CON (CH ₃ )-, or -N (CH ₃ ) CO-; X ² represents a linear or branched alkyl group having a carbon number of 1 to 5; z2 and z8 each independently represent an integer from 1 to 4; z3 and z4 each independently represent an integer from 0 to 4; and (z3 + z4) represents an integer from 1 to 4; z5, z6 and z7 each independently represent an integer from 1 to 5 .

In one embodiment of the present invention, the total mole number based on the diamine component (b) is 100 moles, the diamine compound (b2) having a carboxylic acid group and represented by the formula (b2-1) is used The amount is 30 ~ 90 mol.

In one embodiment of the present invention, the fluorene imidization rate of the polymer (A) is 30 to 90%.

The invention further provides a method for manufacturing a liquid crystal alignment film, which is formed by the liquid crystal alignment agent prepared by the method for manufacturing a liquid crystal alignment agent.

The present invention further provides a liquid crystal display element including the liquid crystal alignment film obtained by the method for manufacturing a liquid crystal alignment film described above.

Based on the above, the liquid crystal alignment agent of the present invention can form a liquid crystal alignment film with excellent environmental resistance because it contains specific compositions (A) and (B).

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

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

Hereinafter, each component of the liquid crystal alignment agent used in the present invention will be described in detail. Polymer ( A )

The polymer (A) is selected from a polyamic acid polymer, a polyimide polymer, a polyimide-based block copolymer, or any combination thereof. The polyimide-based block copolymer is selected from the group consisting of a polyimide block copolymer, a polyimide block copolymer, a polyimide-polyimide block copolymer, or Any combination of the above polymers.

The polymer (A) contains a unit represented by the formula (b1-0): Formula (b1-0) In formula (b1-0), R ^a and R ^b each independently represent a single bond or a straight or branched chain alkyl group having 1 to 10 carbon atoms; Y is -O-, -COO-, -CONR ^c -or -NR ^c- ; R ^c is H or a linear or branched alkyl group having 1 to 3 carbon atoms; Cy is an alicyclic heterocyclic ring or an alicyclic heterocyclic ring containing a substituent; * is Bonding point; the substituent of the above-mentioned alicyclic heterocyclic ring containing a substituent is a straight or branched alkyl group having 1 to 6 carbon atoms, an aromatic ring or an alicyclic ring.

The polyfluorinated acid polymer, the polyfluorinated imine polymer, and the polyfluorinated block copolymer in the polymer (A) may be each composed of a tetracarboxylic dianhydride component (a) and a diamine component (b ). The tetracarboxylic dianhydride component (a), the diamine component (b), and the method for preparing the polymer composition (A) are prepared by the following reaction. Tetracarboxylic dianhydride component ( a )

The tetracarboxylic dianhydride component (a) includes an aliphatic tetracarboxylic dianhydride compound, an alicyclic tetracarboxylic dianhydride compound, an aromatic tetracarboxylic dianhydride compound, and from formula (a-1) to formula (a) -6) At least one of the tetracarboxylic dianhydride compounds represented by the above, or a combination thereof.

Specific examples of the aliphatic tetracarboxylic dianhydride compound may include, but are not limited to, ethane tetracarboxylic dianhydride, butane tetracarboxylic dianhydride, or a combination thereof.

Specific examples of the alicyclic tetracarboxylic dianhydride compound 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-cyclo Butane tetracarboxylic dianhydride, 1,2,3,4-tetramethyl-1,2,3,4-cyclobutane tetracarboxylic dianhydride, 1,2,3,4-cyclopentane tetracarboxylic acid Acid dianhydride, 1,2,4,5-cyclohexanetetracarboxylic dianhydride, 3,3 ', 4,4'-dicyclohexyltetracarboxylic dianhydride, cis-3,7-dibutyl Cycloheptyl-1,5-diene-1,2,5,6-tetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentylacetic dianhydride, bicyclo [2.2.2] -octane- 7-ene-2,3,5,6-tetracarboxylic dianhydride or a combination thereof.

Specific examples of the aromatic tetracarboxylic dianhydride compound may include, but are not limited to, 3,4-dicarboxyl-1,2,3,4-tetrahydronaphthalene-1-succinic dianhydride, pyromellitic dianhydride, 3,3 ', 4,4'-benzophenonetetracarboxylic dianhydride, 3,3', 4,4'-biphenylpyrenetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic acid Acid dianhydride, 2,3,6,7-naphthalenetetracarboxylic 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-furantetracarboxylic dianhydride, 4, 4'-bis (3,4-dicarboxyphenoxy) diphenylsulfide dianhydride, 4,4'-bis (3,4-dicarboxyphenoxy) diphenylarsine dianhydride, 4,4'- Bis (3,4-dicarboxyphenoxy) diphenylpropane dianhydride (4,4'-bis (3,4-dicarboxy phenoxy) diphenylpropane dianhydride), 3,3 ', 4,4'-perfluoroisoprene Propyldiphthalic dianhydride, 3,3 ', 4,4'-diphenyltetracarboxylic dianhydride, bis (phthalic acid) phenylphosphine oxide dianhydride, p-phenylene-bis (tris) Phenylphthalic acid) dianhydride, m-phenylene-bis (triphenylphthalic acid) dianhydride, bis (triphenylphthalic acid) -4,4'-diphenyl ether dianhydride, (Triphenylphthalic acid) -4,4'-diphenylmethane dianhydride, ethylene glycol-bis (anhydrotrimellitic acid ester), propylene glycol-bis (anhydrotrimellitic acid ester), 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 (anhydrotrimellitate), 2,3,4,5-tetrahydrofurantetracarboxylic dianhydride, 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- (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-furanyl) -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- Furanyl) -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-dione, 1,3,3a, 4,5,9b-hexahydro-8-methyl-5- (tetrahydro-2,5-dioxo-3-furyl)- Naphtho [1,2-c] -furan-1,3-dione, 1,3,3a, 4,5,9b-hexahydro-8-ethyl-5- (tetrahydro-2,5-di Pendantoxy-3-furanyl) -naphtho [1,2-c] -furan-1,3-dione, 1,3,3a, 4,5,9b-hexahydro-5,8-dimethyl 5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] -furan-1,3-dione, 5- (2,5-di An aromatic tetracarboxylic dianhydride compound such as pendant oxytetrahydrofuranyl) -3-methyl-3-cyclohexene-1,2-dicarboxylic dianhydride or a combination thereof.

The tetracarboxylic dianhydride compounds represented by formula (a-1) to formula (a-6) are shown below. Formula (a-1) (A-2) (A-3) Formula (a-4) Formula (a-5) In formula (a-5), A ₁ represents a divalent group containing an aromatic ring; r represents an integer of 1 to 2; A ₂ and A ₃ may be the same or different, and may be independently represented by each other -H or alkyl. Specific examples of the tetracarboxylic dianhydride compound represented by the formula (a-5) include at least one of compounds represented by the formula (a-5-1) to the formula (a-5-3). (A-5-1) Formula (a-5-2) Formula (a-5-3) Formula (a-6) In formula (a-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 -H or an alkyl group. The tetracarboxylic dianhydride compound represented by the formula (a-6) is preferably a compound represented by the formula (a-6-1). Formula (a-6-1)

Preferably, the tetracarboxylic dianhydride component (a) includes, but is not limited to, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-cyclopentanetetracarboxylic dianhydride Anhydride, 2,3,5-tricarboxycyclopentylacetic dianhydride, 1,2,4,5-cyclohexanetetracarboxylic dianhydride, 3,4-dicarboxy-1,2,3,4-tetracarboxylic acid Hydronaphthalene-1-succinic dianhydride, pyromellitic dianhydride, 3,3 ', 4,4'-benzophenonetetracarboxylic dianhydride, and 3,3', 4,4'-biphenyl Perylene tetracarboxylic dianhydride. The tetracarboxylic dianhydride component (a) can be used singly or in combination. Diamine component ( b )

The diamine component (b) includes a diamine compound (b1) represented by the formula (b1-1), a diamine compound (b2) having a carboxylic acid group and represented by the formula (b2-1), and other diamines. Compound (b3). Diamine compound ( b1 ) represented by formula (b1-1 )

The diamine compound (b1) represented by the formula (b1-1) contains a unit represented by the above formula (b1-0), and its structure is as follows: Formula (b1-1) In formula (b1-1), R ^a and R ^b each independently represents a single bond or a linear or branched alkyl group having 1 to 10 carbon atoms; Y is -O-, -COO-, -CONR ^c- , or -NR ^c- ; R ^c is -H or a linear or branched alkyl group having 1 to 3 carbon atoms; Cy is an alicyclic heterocyclic ring or an alicyclic heterocyclic ring containing a substituent; The substituent of the above-mentioned substituent-containing alicyclic heterocyclic ring is a linear or branched alkyl group having 1 to 6 carbon atoms, an aromatic ring or an alicyclic ring.

Specific examples of the alicyclic heterocyclic ring or the substituent-containing alicyclic heterocyclic ring include the following formulae (II) to (VIII), but are not limited to these specific examples: Formula (II) Formula (III) Formula (IV) In formulas (II) to (IV), R ^d and R ^e each independently represent -H or a linear or branched alkyl group having 1 to 6 carbon atoms, and R ^d and R ^e may be bonded to form Aromatic ring or alicyclic ring; m is -O-, -S-, or -SO _2- . Formula (V) Formula (VI) Formula (VII) In formula (VIII) In formula (V) to formula (VIII), n and p each independently represent -O- or -S-; q is -O-, -S-, or methylene; R ^f , R ^g , R ^h and R ⁱ each independently represent -H or a linear or branched alkyl group having 1 to 6 carbon atoms; R ^j is -H, a linear or branched alkyl group having 1 to 6 carbon atoms, or carbon number It is a linear or branched alcohol group of 1 to 6, and R ^h and R ⁱ may be bonded to form an aromatic or alicyclic ring, and R ^f and R ⁱ may be bonded to form an aromatic or alicyclic ring.

More specifically, the diamine compound (b1) represented by the formula (b1-1) may include, but is not limited to, the diamine compound represented by the following formula (b1-2) to formula (b1-8): (B1-2) Formula (b1-3) Formula (b1-4) Formula (b1-5) Formula (b1-6) Formula (b1-7) To the formula (B1-8) in a, R ^a, R ^b and Y are as defined with formula (b1-1) is R ^a, R ^b and Y are the same as the formula (B1-8) of formula (b1-2); R ^d, The definition of R ^{e is the} same as that of R ^d and Re in formula (II) to formula (IV) ^; the definitions of n, p, q, R ^f , R ^g , R ^h , R ⁱ and R ^j N, p, q, R ^f , R ^g , R ^h , R ^i, and R ^{j in} formula (VIII) are the same.

More specifically, specific examples of the diamine compound (b1) represented by the formula (b1-1) include diamine compounds represented by the following formula (b1-9) to (b1-135): Formula (b1-9) Formula (b1-10) Formula (b1-11) Formula (b1-12) Formula (b1-13) (B1-14) Formula (b1-15) (B1-16) (B1-17) Formula (b1-18) (B1-19) Formula (b1-20) (B1-21) (B1-22) Formula (b1-23) (B1-24) Formula (b1-25) (B1-26) (B1-27) Formula (b1-28) (B1-29) Formula (b1-30) Formula (b1-31) Formula (b1-32) Formula (b1-33) (B1-34) Formula (b1-35) Formula (b1-36) Formula (b1-37) Formula (b1-38) Formula (b1-39) Formula (b1-40) Formula (b1-41) Formula (b1-42) Formula (b1-43) Formula (b1-44) Formula (b1-45) Formula (b1-46) Formula (b1-47) Formula (b1-48) Formula (b1-49) Formula (b1-50) Formula (b1-51) Formula (b1-52) Formula (b1-53) Formula (b1-54) Formula (b1-55) Formula (b1-56) Formula (b1-57) Formula (b1-58) Formula (b1-59) Formula (b1-60) Formula (b1-61) Formula (b1-62) Formula (b1-63) Formula (b1-64) Formula (b1-65) Formula (b1-66) Formula (b1-67) Formula (b1-68) Formula (b1-69) Formula (b1-70) Formula (b1-71) Formula (b1-72) Formula (b1-73) Formula (b1-74) Formula (b1-75) Formula (b1-76) Formula (b1-77) Formula (b1-78) Formula (b1-79) Formula (b1-80) Formula (b1-81) Formula (b1-82) Formula (b1-83) Formula (b1-84) Formula (b1-85) Formula (b1-86) Formula (b1-87) Formula (b1-88) Formula (b1-89) Formula (b1-90) Formula (b1-91) Formula (b1-92) Formula (b1-93) Formula (b1-94) Formula (b1-95) Formula (b1-96) Formula (b1-97) Formula (b1-98) Formula (b1-99) Formula (b1-100) Formula (b1-101) Formula (b1-102) Formula (b1-103) Formula (b1-104) Formula (b1-105) Formula (b1-106) Formula (b1-107) Formula (b1-108) Formula (b1-109) Formula (b1-110) Formula (b1-111) Formula (b1-112) Formula (b1-113) Formula (b1-114) Formula (b1-115) Formula (b1-116) Formula (b1-117) Formula (b1-118) Formula (b1-119) Formula (b1-120) Formula (b1-121) Formula (b1-122) Formula (b1-123) Formula (b1-124) Formula (b1-125) Formula (b1-126) Formula (b1-127) Formula (b1-128) Formula (b1-129) Formula (b1-130) Formula (b1-131) Formula (b1-132) Formula (b1-133) Formula (b1-134) Formula (b1-135)

The diamine compound (b1) represented by the formula (b1-1) may be used alone or in combination.

Based on the total mole number of the diamine component (b) is 100 moles, the amount of the diamine compound (b1) represented by the formula (b1-1) is 5 to 35 moles, preferably 8 to 35 Mohr, more preferably 8-30 Moore.

When the diamine component (b) of the polymer (A) in the liquid crystal alignment agent does not contain the diamine compound (b1) represented by the formula (b1-1), the environmental resistance of the liquid crystal display element is not good. . Diamine compound ( b2 ) having a carboxylic acid group and represented by formula (b2-1 )

The diamine compound (b2) having a carboxylic acid group and represented by the formula (b2-1) is as follows: Formula (b2-1) In formula (b2-1), X represents an organic group having an aromatic ring having 6 to 30 carbon atoms; z1 represents an integer of 1 to 4.

The diamine compound (b2) which has a carboxylic acid group and is represented by Formula (b2-1) should just have a carboxylic acid group, and the structure is not specifically limited. The diamine compound (b2) having a carboxylic acid group and represented by the formula (b2-1) may include, but is not limited to, an aliphatic diamine, an alicyclic diamine, an aromatic diamine, or a diamine-based organosiloxane. The diamine compound (b2) having a carboxylic acid group and represented by the formula (b2-1) is preferably an alicyclic diamine or an aromatic diamine, and more preferably an aromatic diamine.

The diamine compound (b2) having a carboxylic acid group and represented by the formula (b2-1) may preferably have 1 to 4 carboxylic acid groups, and more preferably has 1 or 2 carboxylic acid groups.

Specifically, the diamine compound (b2) having a carboxylic acid group and represented by the formula (b2-1) may include, but is not limited to, a diamine represented by the following formula (b2-2) to (b2-6) Amine compounds: Formula (b2-2) (B2-3) (B2-4) Formula (b2-5) Formula (b2-6) In formulas (b2-2) to (b2-6), X ¹ and X ³ each independently represent a single bond, -CH _2- , -C ₂ H _4- , -C (CH ₃ ) _2- , -CF _2- , -C (CF ₃ ) _2- , -O-, -CO-, -NH-, -N (CH ₃ )-, -CONH-, -NHCO-, -CH ₂ O- , -OCH _2- , -COO-, -OCO-, -CON (CH ₃ )-or -N (CH ₃ ) CO-; X ² represents a linear or branched alkyl group having a carbon number of 1 to 5; z2 And z8 each independently represent an integer from 1 to 4; z3 and z4 each independently represent an integer from 0 to 4; and (z3 + z4) represents an integer from 1 to 4; z5, z6 and z7 each independently represent an integer from 1 to 5.

Preferably, in the formula (b2-2), z2 may represent 1 or 2; in the formula (b2-3), X ¹ represents a single _{bond, -CH 2 -, - C 2} H 4 -, - C ( CH ₃ ) _2- , -O-, -CO-, -NH-, -N (CH ₃ )-, -CONH-, -NHCO-, -COO-, or -OCO-, and z3 and z4 represent 1 at the same time; In formula (b2-6), X ³ represents a single bond, -CH _2- , -O-, -CO-, -NH-, -CONH-, -NHCO-, -CH ₂ O-, -OCH _2- , -COO- or -OCO-, and z8 represents 1 or 2.

More specifically, examples of the diamine compound (b2) having a carboxylic acid group and represented by the formula (b2-1) include diamine compounds represented by the following formula (b2-7) to (b2-17) Specific examples: (B2-7) Formula (b2-8) (B2-9) Formula (b2-10) (B2-11) (B2-12) (B2-13) (B2-14) (B2-15) (B2-16) Formula (b2-17) In formula (b2-15) and formula (b2-16), X ⁴ represents a single bond, -CH _2- , -O-, -CO-, -NH-, -CONH-, -NHCO -, -CH ₂ O-, -OCH _2- , -COO- or -OCO-.

The diamine compound (b2) which has a carboxylic acid group and is represented by Formula (b2-1) can be used individually or in combination of multiple types.

The total mole number based on the diamine component (b) is 100 moles, the amount of the diamine compound (b2) having a carboxylic acid group represented by the formula (b2-1) is 30 to 90 moles, It is preferably 40 to 80 moles, more preferably 45 to 75 moles.

When the diamine component (b) of the polymer (A) in the liquid crystal alignment agent contains a diamine compound (b2) having a carboxylic acid group and represented by the formula (b2-1), the environmental resistance can be further improved. Sex. Other diamine compounds ( b3 )

The other diamine compound (b3) includes an aliphatic diamine compound, an alicyclic diamine compound, an aromatic diamine compound, a diamine compound having a formula (b3-1) to a formula (b3-25), or a combination thereof.

Specific examples of the aliphatic diamine compound 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) ethyl Alkane, or a combination of the above.

Specific examples of the alicyclic diamine compound include, but are not limited to, 4,4'-diaminodicyclohexylmethane, 4,4'-diamino-3,3'-dimethyldicyclohexylamine, 1, 3-diaminocyclohexane, 1,4-diaminocyclohexane, isophorone diamine, tetrahydrodicyclopentadiene diamine, tricyclo [6.2.1.0 ^2,7 ] -undec Carbenedimethyldiamine, 4,4'-methylenebis (cyclohexylamine), or a combination thereof.

Specific examples of the aromatic diamine compound include, but are not limited to, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylethane, 4,4'-diaminodiphenyl Hydrazone, 4,4'-diaminobenzylanilide, 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-methyl bridged indenyl dimethylene diamine, 3,3'-diamino benzophenone, 3,4'-diamine di 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] Hydrazone, 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 isopropylidene) bisaniline, 4,4'-(m-phenylene isopropylidene) bisaniline , 2,2'-bis [4- (4-amino-2-trifluoromethylphenoxy) phenyl] hexafluoropropane, 4,4'-bis [(4-amino-2-trifluoro Methyl) phenoxy] -octafluorobiphenyl, 5- [4- (4-n-pentylcyclohexyl) 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 thereof.

The diamine compounds having the formula (b3-1) to the formula (b3-25) are shown below. Formula (b3-1) In formula (b3-1), B ¹ represents , , , , ,or ; B ² represents a group having a steroid (cholesterol) skeleton, a trifluoromethyl group, a fluoro group, an alkyl group having 2 to 30 carbon atoms, or derived from pyridine, pyrimidine, triazine, piperidine, or piperazine, etc. A monovalent group containing a nitrogen atom ring structure.

Specific examples of the compound represented by the formula (b3-1) include, but are not limited to, 2,4-diaminophenyl ethyl formate, 3,5-diaminophenyl ethyl formate Ester (3,5-diaminophenyl ethyl formate), 2,4-diaminophenyl propyl formate, 3,5-diaminophenyl propyl formate (3,5- diaminophenyl propyl formate), 1-dodecoxy-2,4-diaminobenzene, 1-dodecoxy-2,4-diaminobenzene, 1-dodecoxy-2,4-diaminobenzene ( 1-hexadecoxy-2,4-diaminobenzene), 1-octadecoxy-2,4-diaminobenzene, from formula (b3-1-1) to formula At least one of the compounds represented by (b3-1-6), or a combination thereof.

The compounds represented by the formula (b3-1-1) to the formula (b3-1-6) are shown below. Formula (b3-1-1) Formula (b3-1-2) Formula (b3-1-3) Formula (b3-1-4) Formula (b3-1-5) Formula (b3-1-6)

In the formula (B3-2) of formula (B3-2), and B ¹ in the formula (b3-1) B same as ^1, B ³ and B ⁴ each independently represents a divalent aliphatic ring, aromatic ring or two divalent Valent heterocyclic group; B ⁵ represents an alkyl group having 3 to 18 carbon atoms, an alkoxy group having 3 to 18 carbon atoms, a fluoroalkyl group having 1 to 5 carbon atoms, and a fluoroalkane having 1 to 5 carbon atoms Oxygen, cyano or halogen atom.

Specific examples of the compound represented by the formula (b3-2) include at least one of compounds represented by the following formulae (b3-2-1) to (b3-2-13): Formula (b3-2-1) Formula (b3-2-2) Formula (b3-2-3) Formula (b3-2-4) Formula (b3-2-5) Formula (b3-2-6) Formula (b3-2-7) Formula (b3-2-8) Formula (b3-2-9) Formula (b3-2-10) Formula (b3-2-11) Formula (b3-2-12) Formula (b3-2-13) In formula (b3-2-1) to formula (b3-2-13), s represents an integer of 3 to 12.

Formula (b3-3) In formula (b3-3), B ⁶ each independently represents a hydrogen atom, a fluorenyl group having 1 to 5 carbon atoms, an alkyl group having 1 to 5 carbon atoms, and an alkane having 1 to 5 carbon atoms. An oxygen or 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 the compound represented by the formula (b3-3) include when u is 1: p-diaminebenzene, m-diaminebenzene, o-diaminebenzene, 2,5-diaminotoluene, and the like; when u When 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 the like.

Specific examples of the compound represented by the formula (b3-3) preferably include p-diaminebenzene, 2,5-diaminotoluene, 4,4'-diaminobiphenyl, 3,3'-dimethyl Oxy-4,4'-diaminobiphenyl, 1,4-bis (4'-aminophenyl) benzene or a combination thereof.

Formula (b3-4) In formula (b3-4), v represents an integer of 2-12.

Formula (b3-5) In Formula (b3-5), w represents an integer of 1 to 5. The compound represented by formula (b3-5) is preferably 4,4'-diamino-diphenylsulfide.

Formula (b3-6) In formula (b3-6), B ⁷ and B ⁹ each independently represent a divalent organic group, and B ⁷ and B ⁹ may be the same or different; B ⁸ represents a derivative derived from pyridine, pyrimidine, tris Divalent group of a cyclic structure containing a nitrogen atom such as azine, piperidine, or piperazine.

Formula (b3-7) In formula (b3-7), B ¹⁰ , B ¹¹ , B ¹² and B ¹³ each independently represent a hydrocarbon group having 1 to 12 carbon atoms, and B ¹⁰ , B ¹¹ , B ¹² and B ¹³ may be Are the same or different; x1 each independently represents an integer from 1 to 3; x2 represents an integer from 1 to 20.

Formula (b3-8) In formula (b3-8), B ¹⁴ represents an oxygen atom or a cyclohexane group; B ¹⁵ represents a methylene group; B ¹⁶ represents a phenyl group or a cyclohexane group; B ¹⁷ represents hydrogen Atom or heptyl.

Specific examples of the compound represented by the formula (b3-8) include a compound represented by the formula (b3-8-1), a compound represented by the formula (b3-8-2), or a combination thereof: Formula (b3-8-1) Formula (b3-8-2)

The compounds represented by the formula (b3-9) to the formula (b3-25) are shown below. Formula (b3-9) Formula (b3-10) (B3-11) Formula (b3-12) Formula (b3-13) (B3-14) (B3-15) (B3-16) (B3-17) (B3-18) (B3-19) Formula (b3-20) Formula (b3-21) Formula (b3-22) (B3-23) Formula (b3-24) Formula (b3-25) In formulas (b3-17) to (b3-25), B ^{18 is} preferably an alkyl group having 1 to 10 carbon atoms or an alkoxy group having 1 to 10 carbon atoms; B ¹⁹ It preferably represents a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or an alkoxy group having 1 to 10 carbon atoms.

Formula (b3-26) In formula (b3-26), B ²⁰ and B ²² each independently represent a single bond, -O-, -COO-, or -OCO-; B ²¹ is an alkylene group having 1 to 3 carbon atoms ; B ²³ is a single bond or an alkylene group having 1 to 3 carbon atoms. d and g each independently represent 0 or 1; e represents an integer from 0 to 2; f represents an integer from 1 to 20; wherein d and e are not 0 at the same time.

In the formula (b3-26), the divalent group represented by "-B ^20- (B ²¹ -B ²² ) _g- " is preferably an alkylene group having 1 to 3 carbon atoms, * -O-, * -COO- or * -OC ₂ H ₄ -O- (wherein * represents a bond to a diaminophenyl group.). The group represented by "-C _f H _{2f +1} " is preferably linear. The positions of two amine groups in the diaminophenyl group with respect to other groups are preferably the 2, 4-position or the 3, 5-position.

Specific examples of the compound represented by the formula (b3-26) include compounds represented by the following formula (b3-26-1) to (b3-26-4): (B3-26-1) (B3-26-2) (B3-26-3) (B3-26-4)

The diamine component (b) may be used alone or in combination.

Specific examples of the diamine component (b) 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, 2,4-diaminophenylcarboxylic acid ethyl ester, 1-deca Octaalkoxy-2,4-diaminobenzene, compound represented by formula (b3-1-1), compound represented by formula (b3-1-2), represented by formula (b3-2-1) Compound, compound represented by formula (b3-2-11), p-diaminebenzene, m-diaminebenzene, o-diaminebenzene, compound represented by formula (b3-8-1), or the above compound The combination.

The total mole number based on the diamine component (b) is 100 moles. The amount of other diamine compounds (b3) used is 0 to 95 moles, preferably 10 to 90 moles, and more preferably 15 to 85. Mor. Method for preparing polymer ( A )

The polymer (A) may include at least one of a polyamidic acid and a polyimide. The polymer (A) may further include a polyfluorene-based block copolymer. The methods for preparing the various polymers described above 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 a tetracarboxylic dianhydride component (a) and a diamine component (b), and polymerize at a temperature of 0 ° C to 100 ° C. Condensation reaction. After reacting for 1 hour to 24 hours, the reaction solution is distilled under reduced pressure using an evaporator to obtain polyamic acid. Alternatively, the reaction solution is poured into a large amount of a lean solvent to obtain a precipitate. Then, the precipitate is dried under reduced pressure to obtain polyamic acid.

Based on the total mole number of the diamine component (b) is 100 moles, and the amount of the tetracarboxylic dianhydride component (a) is 20 to 200 moles; more preferably, the tetracarboxylic dianhydride group Part (a) is used in an amount of 30 to 120 mol.

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 reactant and the product. The solvent preferably includes, but is not limited to (1) an aprotic polar solvent, such as: N-methyl-2-pyrrolidinone (NMP), N, N-dimethylacetamide, Aprotic polar solvents such as N, N-dimethylformamide, dimethylmethylene sulfoxide, γ-butyrolactone, tetramethylurea or hexamethyl phosphate triamine; or (2) phenolic solvents, For example: m-cresol, xylenol, phenol or halogenated phenols. The use amount of the solvent used in the polycondensation reaction is preferably 200 parts by weight to 2000 parts by weight, and more preferably 300 parts by weight to 1800 parts by weight based on the total use amount of the mixture.

It is worth noting that in the polycondensation reaction, an appropriate amount of a lean solvent can be used in combination with the solvent, wherein the lean solvent does not cause the polyamic acid to precipitate. The lean solvent can be used singly or in combination, and it includes but is not limited to (1) alcohols, such as: methanol, ethanol, isopropanol, cyclohexanol, ethylene glycol, propylene glycol, 1,4-butane Alcohols or alcohols such as triethylene glycol; (2) ketones, such as: ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone; (3) esters, such as: Esters such as 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 dimethyl ether Ethers such as alkyl ethers; (5) halogenated hydrocarbons, such as: dichloromethane, 1,2-dichloroethane, 1,4-dichlorobutane, trichloroethane, chlorobenzene, or o-dichloro Halogenated hydrocarbons such as benzene; or (6) hydrocarbons, for example: hydrocarbons such as tetrahydrofuran, hexane, heptane, octane, benzene, toluene or xylene, or any combination of the above solvents. Based on the used amount of the diamine component (b) being 100 parts by weight, the amount of the lean solvent is preferably 0 to 60 parts by weight, and more preferably 0 to 50 parts by weight. Method for preparing polyfluorene

The method for preparing polyimide is obtained by heating the polyamidic acid prepared by the method for preparing polyamidic acid in the presence of a dehydrating agent and a catalyst. During the heating process, the arsenic acid functional group in the polyarsenic acid can be converted into the arsonimine functional group (that is, arsonimation) through a dehydration ring-closing reaction.

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

In order to obtain a better degree of polyimidation of the polyimide, the operating temperature of the dehydration ring-closing reaction is preferably 40 ° C to 200 ° C, and 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 is not complete, and the degree of imidization of the polyacid is 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 polyfluorene imine is low.

The dehydrating agent used in the dehydration ring-closure reaction may be selected from acid anhydride compounds, and specific examples thereof include acid anhydride compounds such as acetic anhydride, propionic anhydride, and trifluoroacetic anhydride. Based on 1 mole of polyamic acid, the amount of dehydrating agent used is 0.01 to 20 moles. The catalyst used in the dehydration ring-closing reaction may be selected from (1) pyridine compounds, such as pyridine, trimethylpyridine, or dimethylpyridine; and (2) tertiary amine compounds, such as: Tertiary amines such as triethylamine. Based on the amount of dehydrating agent used is 1 mole, the amount of catalyst used can be 0.5 to 10 moles.

The amidation ratio of the polymer (A) may be 30% to 90%, preferably 35% to 85%, and more preferably 40% to 80%. When the fluorene imidization rate of the polymer (A) in the liquid crystal alignment agent is within the above range, the environmental resistance can be further improved. Method for preparing polyfluorene imide block copolymer

The polyimide-based block copolymer is selected from the group consisting of a polyimide block copolymer, a polyimide block copolymer, a polyimide-polyimide block copolymer, or the above-mentioned polymerization. Any combination of things.

The method for preparing a polyfluorene-based block copolymer is preferably firstly dissolving a starting material in a solvent and performing a polycondensation reaction, wherein the starting material includes at least one polyamidic acid and / or at least one polyfluorene The imine may further include a tetracarboxylic dianhydride component (a) and a diamine component (b).

The tetracarboxylic dianhydride component and the diamine component in the starting material may be the same as the tetracarboxylic dianhydride component (a) and the diamine component (b) used in the method for preparing a polyamic acid, In addition, the solvent used in the polycondensation reaction may be the same as the solvent (B) in the liquid crystal alignment agent described below, and details are not described herein again.

The used amount of the solvent used in the polycondensation reaction is preferably 200 to 2000 parts by weight, and more preferably 300 to 1800 parts by weight based on the used amount 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 materials preferably include, but are not limited to, (1) two polyamido acids having different terminal groups and different structures; (2) two polyimines having different terminal groups and different structures; (3) ) Polyamidic acid and polyimide having different terminal groups and different structures; (4) Polyamidic acid, tetracarboxylic dianhydride component and diamine component, of which, tetracarboxylic dianhydride component And at least one of the diamine component is different from the structure of the tetracarboxylic dianhydride component and the diamine component used to form the polyamidic acid; (5) the polyamidoimide and the tetracarboxylic dianhydride group And diamine components, wherein at least one of the tetracarboxylic dianhydride component and the diamine component is different from the structure of the tetracarboxylic dianhydride component and the diamine component used to form the polyimide ; (6) at least one of a polyamine acid, a polyimide, a tetracarboxylic dianhydride component, and a diamine component, wherein at least one of the tetracarboxylic dianhydride component and the diamine component forms a polyamine The structure of the tetracarboxylic dianhydride component used by the acid or polyimide is different from that of the diamine component; (7) Two kinds of polyamidic acid, tetracarboxylic dianhydride component and diamine having different structures Component; (8) two structural phases Polyimide, tetracarboxylic dianhydride component and diamine component; (9) two polyamines and diamine components whose terminal groups are acid anhydride groups and different in structure; (10) two kinds of terminals Polyamines and tetracarboxylic dianhydride components whose groups are amine groups and are different in structure; (11) Polyimide and diamine components whose terminal groups are acid anhydride groups and are different in structure; or (12 ) Two kinds of polyimide and tetracarboxylic dianhydride components whose terminal groups are amine groups and have different structures.

As long as the efficacy of the present invention is not affected, the polyamidic acid, polyamidoimide, and polyamidoimide block copolymer are preferably terminally modified polymers after molecular weight adjustment. By using a terminal-modified polymer, the coating performance of the liquid crystal alignment agent can be improved. The method for preparing the terminal-modified polymer can be prepared by adding a polyfunctional compound while the polyamic acid is undergoing a polycondensation reaction.

Specific examples of monofunctional compounds include, but are not limited to (1) monobasic anhydrides, such as: maleic anhydride, phthalic anhydride, itaconic anhydride, n-decylsuccinic anhydride, n-dodecylsuccinic anhydride, n-tetradecyl Monobasic 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-tetradecanylamine, n-pentadecylamine, n-hexadecylamine, n-heptadecanylamine, 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 as measured by Gel Permeation Chromatography (GPC) of 2,000 to 200,000, preferably 3,000 to 100,000, and 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 is a soluble polymer (A) and any other component and does not react therewith, it is preferably the same as that in the aforementioned synthetic polyamide. The solvent to be used may be used in combination with the lean solvent used in the synthesis of the polyamic acid.

Specific examples of the solvent (B) include, but are not limited to, N-methyl-2-pyrrolidone, γ-butyrolactone, γ-butyrolactam, 4-hydroxy-4-methyl-2-pentanone, and ethylene glycol Monomethyl ether, butyl lactate, butyl acetate, methyl methoxypropionate, ethyl ethoxypropionate, 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, ethylene glycol ethyl ether acetate, diethylene 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-dimethyl acetamide, etc. The solvent (B) may be used alone or in combination.

Based on 100 parts by weight of the polymer (A), 500 to 5,000 parts by weight of the solvent (B), preferably 800 to 4500 parts by weight, and more preferably 1,000 to 4,000 parts by weight. Additive ( C )

To the extent that the efficacy of the present invention is not affected, the liquid crystal alignment agent may optionally add an additive (C), where the additive (C) includes an epoxy compound, a silane compound having a functional group, or a combination thereof. The function of the additive (C) is to improve the adhesion between the liquid crystal alignment film and the substrate surface.

Epoxy compounds 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 Propyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerol diglycidyl ether, 2,2-dibromo neopentyl glycol di Glycidyl ether, 1,3,5,6-tetraglycidyl-2,4-hexanediol, N, N, N ', N'-tetraglycidyl-m-xylylenediamine , 1,3-bis (N, N-diepoxypropylaminomethyl) cyclohexane, N, N, N ', N'-tetraepoxypropyl-4,4'-diaminodiamine Phenylmethane, 3- (N, N-diglycidyl) aminopropyltrimethoxysilane, or a combination of the foregoing.

The epoxy compound may be used alone or in combination.

The use amount of the epoxy compound may be 0 to 40 parts by weight, and preferably 0.1 to 30 parts by weight based on the use amount of the polymer (A).

Specific examples of the silane compound having a functional group include, but are not limited to, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 2-aminopropyltrimethoxysilane, 2 -Aminopropyltriethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropyl Methyldimethoxysilane, 3-ureidopropyltrimethoxysilane, 3-ureidopropyltrimethoxysilane, N-ethoxycarbonyl-3-aminopropyl Trimethoxysilane, N-ethoxycarbonyl-3-aminopropyltriethoxysilane, N-triethoxysilylpropyltriethylenetriamine, N-trimethoxysilylpropyltriamine Ethylenetriamine, 10-trimethoxysilyl-1,4,7-triazine, 10-triethoxysilyl-1,4,7-triazine, 9-trimethoxysilane -3,6-diazinyl acetate, 9-triethoxysilyl-3,6-diazinyl acetate, N-benzyl-3-aminopropyltrimethoxysilane, N -Benzyl-3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltriethoxy Silane, N- bis (oxyethylene) -3-aminopropyl trimethoxy Silane, N- bis (oxyethylene) -3-aminopropyl triethoxysilane Silane, or combinations of the above compounds.

The silane compound having a functional group may be used alone or in combination.

The use amount of the silane compound having a functional group may be 0 to 10 parts by weight, and preferably 0.5 to 10 parts by weight based on the use amount of the polymer (A).

The use amount of the additive (C) is preferably 0.5 to 50 parts by weight, and more preferably 1 to 45 parts by weight, based on the total use amount of the polymer (A). < Manufacturing method of liquid crystal alignment agent >

The manufacturing method of the liquid crystal alignment agent is not particularly limited, and it can be prepared by a general mixing method. For example, the tetracarboxylic dianhydride component (a) and the diamine component (b) are first mixed uniformly to form a polymer (A). Next, the polymer (A) is added to the solvent (B) at a temperature of 0 ° C. to 200 ° C., and the additive (C) can be optionally added, and the stirring device can be continuously stirred until dissolved. Preferably, the solvent (B) is added to the polymer at a temperature of 20 ° C to 60 ° C.

Preferably, at 25 ° C, the viscosity of the liquid crystal alignment agent of the present invention is usually 15 cps to 35 cps, preferably 17 cps to 33 cps, and more preferably 20 cps to 30 cps. < Manufacturing method of liquid crystal alignment film >

The liquid crystal alignment film of the present invention can be formed of the liquid crystal alignment agent described above.

Specifically, the preparation method of the liquid crystal alignment film may be, for example, applying a liquid crystal alignment agent on a surface of a substrate by a method such as a roll coating method, a spin coating method, a printing method, or an ink-jet method. To form a pre-coating. Then, a pre-bake treatment, a post-bake treatment, and an alignment treatment are performed on the pre-coat layer to obtain a substrate on which a liquid crystal alignment film is formed.

The purpose of the pre-baking treatment is to volatilize the organic solvent in the pre-coating. The operating temperature of the pre-baking treatment is preferably 30 ° C to 120 ° C, more preferably 40 ° C to 110 ° C, and even more preferably 50 ° C to 100 ° C.

There is no particular limitation on the alignment treatment. Cloths made of fibers such as nylon, rayon, or cotton can be wound on a drum and aligned by rubbing in a certain direction.

The purpose of the post-baking treatment step is to make the polymer in the pre-coating layer undergo a further dehydration ring closure (fluorine imidization) reaction. The operating temperature of the post-baking treatment is preferably 150 ° C to 300 ° C, more preferably 180 ° C to 280 ° C, and even more preferably 200 ° C to 250 ° C. < Liquid crystal display element and manufacturing method thereof >

The liquid crystal display element of the present invention includes a liquid crystal alignment film formed of the liquid crystal alignment agent of the present invention. The manufacturing method of the liquid crystal display element is well known to those skilled in the art. Therefore, the following is simply stated.

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. 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. The first conductive film 114 is formed on a 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 on 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. The second conductive film 124 is formed on a 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 cell 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. The transparent materials include, but are not limited to, alkali-free glass, soda-lime glass, hard glass (Pales glass), and quartz glass used in liquid crystal display devices. , Polyethylene terephthalate, polybutylene terephthalate, polyether fluorene or polycarbonate.

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.

Each of the first liquid crystal alignment film 116 and the second liquid crystal alignment film 126 is the above-mentioned liquid crystal alignment film, and its role is to form a pretilt angle of the liquid crystal cell 130. 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. This electric field can drive the liquid crystal cell 130, thereby changing the arrangement of liquid crystal molecules in the liquid crystal cell 130.

The liquid crystal used in the liquid crystal unit 130 may be used alone or in combination. The liquid crystal includes, but is not limited to, a diaminobenzene liquid crystal, a pyridazine liquid crystal, a shiff base liquid crystal, and an azo oxide ( azoxy) liquid crystal, biphenyl liquid crystal, phenylcyclohexane liquid crystal, ester liquid crystal, terphenyl, biphenylcyclohexane liquid crystal, pyrimidine ( pyrimidine-based liquid crystals, dioxane-based liquid crystals, bicyclooctane-based liquid crystals or cubane-based liquid crystals, etc., and can be added as needed, such as cholesterol cholesterol, cholesterol Cholesteric liquid crystals such as cholesteryl nonanoate, cholesteryl carbonate, etc., or chiral agents under the trade names "C-15" and "CB-15" (Merck) Or a ferroelectric liquid crystal such as p-decoxybenzylidene-p-amino-2-methylbutyl cinnamate.

Hereinafter, the present invention will be described in detail with examples, but the present invention is not limited to the contents disclosed in these examples. < Example > Synthesis example of polymer ( A )

Synthetic Examples A-1-1 to A-1-5, Synthetic Examples A-2-1 to A-2-10, and Comparative Synthetic Examples A-3-1 to Polymer-A are described below. Comparative Synthesis Example A-3-7:

Synthesis Example A-1-1

A 500 ml four-necked flask was provided with a nitrogen inlet, a stirrer, a condenser, and a thermometer, and nitrogen was introduced. Then, in a four-necked flask, 0.591 g (0.0025 mole) of the compound represented by formula (b1-87) (abbreviated as b1-a) and 3.78 g (0.035 mole) of p-diaminebenzene ( Abbreviated as b3-a), 5.38 g (0.0125 mole) of the compound represented by formula (b3-26-2) (abbreviated as b3-f), and 80 g of N-methyl-2-pyrrolidone (N- methyl-2-pyrrolidone (abbreviated as NMP), and stirred at room temperature until dissolved. Next, 11.2 g (0.05 mol) of 2,3,5-tricarboxycyclopentylacetic dianhydride (abbreviated as a1) and 20 g of NMP were added and reacted at room temperature for 2 hours. After the reaction is completed, the reaction solution is poured into 1500 ml of water to precipitate a polymer. Then, the obtained polymer was filtered, repeatedly washed with methanol and filtered three times, put into a vacuum oven, and dried at a temperature of 60 ° C. to obtain a polymer (A-1-1).

Synthesis Example A-1-2 to Synthesis Example A-1-5, and Comparative Synthesis Example A-3-2

Synthesis Example A-1-2 to Synthesis Example A-1-5 and Comparative Synthesis Example A-3-2 The polymers (A-1-2) were prepared by the same procedures as in Synthesis Example A-1-1, respectively. To the polymer (A-1-5) and the polymer (A-3-2), and the difference is that the type of the monomer and the amount of use thereof are changed (as shown in Tables 1 and 2).

Synthesis Example A-2-1

A 500 ml four-necked flask was provided with a nitrogen inlet, a stirrer, a condenser, and a thermometer, and nitrogen was introduced. Then, in a four-necked flask, 0.708 g (0.0025 mol) of the compound represented by formula (b1-81) (abbreviated as b1-f) and 3.78 g (0.035 mol) of p-diaminebenzene ( Abbreviated as b3-a), 5.38 g (0.0125 mol) of the compound represented by formula (b3-26-2) (abbreviated as b3-f) and 80 g of NMP, and stirred at room temperature until dissolved. Next, 11.2 g (0.05 mol) of 2,3,5-tricarboxycyclopentylacetic dianhydride (abbreviated as a1) and 20 g of NMP were added. 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 the imidization reaction. After the reaction is completed, the reaction solution is poured into 1500 ml of water to precipitate a polymer. Then, the obtained polymer was filtered, and repeatedly washed with methanol and filtered three times, put into a vacuum oven, and dried at a temperature of 60 ° C. to obtain a polymer (A-2-1).

Synthesis Example A-2-2 to Synthesis Example A-2-10, Comparative Synthesis Example A-3-1, and Comparative Synthesis Example A-3-3 to Comparative Synthesis Example A-3-7

Synthesis Example A-2-2 to Synthesis Example A-2-10, Comparative Synthesis Example A-3-1, and Comparative Synthesis Example A-3-3 to Comparative Synthesis Example A-3-7 are the same as in Synthesis Example A- 2-1 The same steps were used to prepare polymer (A-2-2) to polymer (A-2-10), polymer (A-3-1), and polymer (A-3-3) to Polymer (A-3-7), and its difference lies in: changing the type of monomer and its amount of use (as shown in Table 1, Table 2).

The compounds corresponding to the numbers in Tables 1 and 2 are shown below.

[Table 1]

[Table 2] Examples and comparative examples of liquid crystal alignment agents, liquid crystal alignment films, and liquid crystal display elements

Examples 1 to 15 and Comparative Examples 1 to 7 of the liquid crystal alignment agent, the liquid crystal alignment film, and the liquid crystal display element will be described below:

a. Liquid crystal alignment agent

100 parts by weight of the polymer (A-1-1) and 500 parts by weight of N-methyl-2-pyrrolidone (abbreviated as B-1) were weighed and stirred at room temperature to form the liquid crystal of Example 1. Alignment agent.

b. Liquid crystal alignment film and liquid crystal display element

The above-mentioned liquid crystal alignment agent was respectively applied to two glass substrates having a conductive film made of ITO (indium-tin-oxide) by a printer (manufactured by Japan Photo Printing Co., Ltd., model S15-036) to form a pre-form. coating. Thereafter, the glass substrate was placed on a hot plate, and pre-baked under conditions of a temperature of 100 ° C. and a time of 5 minutes. Next, post-baking was performed in a circulating oven under the conditions of a temperature of 220 ° C and a time of 30 minutes. Finally, after the alignment process, the glass substrate on which the liquid crystal alignment film of Example 1 is formed can be obtained.

One of the two glass substrates with the liquid crystal alignment film formed thereon was coated with hot-press adhesive, and the other one was coated with a 4 μm spacer. Next, the two glass substrates were bonded together, and then a pressure of 10 kg was applied with a hot press, and the bonding was performed by hot pressing at a temperature of 150 ° C. Then, liquid crystal injection was performed using a liquid crystal injection machine (made by Shimadzu Corporation, model number: ALIS-100X-CH). Next, the liquid crystal injection port is sealed with an ultraviolet curing adhesive, and the ultraviolet curing adhesive is hardened with the ultraviolet light, and the liquid crystal is subjected to an annealing treatment in an oven at a temperature of 60 ° C and a time of 30 minutes. That is, the liquid crystal display element of Example 1 can be obtained.

The liquid crystal display element of Example 1 was evaluated by each evaluation method described later, and the results are shown in Table 3.

Examples 2 to 15

The liquid crystal alignment agent, liquid crystal alignment film, and liquid crystal display element of Example 2 to Example 15 were separately prepared in the same steps as in Example 1, and the difference was that the type of the component and the amount of use were changed, as shown in Table 3. Show. The liquid crystal display elements obtained in Examples 2 to 15 were evaluated in an evaluation method described later, and the results are shown in Tables 3 and 4.

Comparative Example 1 to Comparative Example 7

The liquid crystal alignment agent, liquid crystal alignment film, and liquid crystal display element of Comparative Example 1 to Comparative Example 7 were separately prepared in the same steps as in Example 1. The difference was that the type of the component and the amount of use were changed, as shown in Table 4. . The liquid crystal display elements obtained in Comparative Examples 1 to 7 were evaluated in the evaluation method described later, and the results are shown in Table 4.

The compounds corresponding to the abbreviations in Tables 3 and 4 are shown below.

Evaluation method

a. 醯 imidization rate

The fluorene imidization ratio refers to the total number of fluorene imine functional groups and the number of fluorene imine rings in the polymer, and the ratio of the number of fluorene imine rings is calculated as a percentage.

The detection method is to separately dry the polymer of the synthesis example under reduced pressure, and then dissolve it in an appropriate deuteration solvent (for example: deuterated dimethylsulfine), using tetramethylsilane as a reference material, ¹ H-NMR measurement results ^{(1 H-Nuclear magnetic resonance,} 1 H-NMR) at room temperature (e.g. 25 ℃), then from equation (1) can be obtained (PEI) ratio (%). Mathematical formula (1) Δ1: peak area generated by chemical shift of NH matrix proton around 10 ppm; Δ2: peak area of other protons; α: precursor of polymer (polyamic acid) The ratio of the number of one proton of the NH group to the other protons in the NH group.

b. Environmental resistance

The liquid crystal display elements of the examples and comparative examples were respectively placed in an environment having a temperature of 65 ° C. and a relative humidity of 85%. After 120 hours, the examples were measured using an electric measuring machine (manufactured by Toyo Co., Model 6254). The ion density of the liquid crystal display elements of 1 to Example 13 and Comparative Examples 1 to Comparative Example 6. The test condition is that a triangle wave of 1.7 volts and 0.01 Hz is applied at a temperature of 60 ° C. The ion density (pC) can be measured by calculating the peak area in the range of 0 to 1 volt in the current-voltage waveform. The lower the ion density, the better the environmental resistance.

The evaluation criteria of ion density are shown below. ◎: Ion density <20 ○: 20 ≦ Ion density <40 △: 40 ≦ Ion density ＜ 50 ╳: 50 ≦ Ion density

[table 3]

[Table 4] ＜ Evaluation results ＞

It is known from Tables 3 and 4 that when the diamine component (b) of the polymer (A) in the liquid crystal alignment agent does not include at least one diamine compound (b1) represented by the formula (b1-1) (comparative In Examples 1 to 7), the environmental resistance of the liquid crystal display element was not good.

In addition, when the diamine component (b) of the polymer (A) in the liquid crystal alignment agent further includes a diamine compound (b2) having a carboxylic acid group and represented by the formula (b2-1) (Examples 2 to 15) ), The environmental resistance of the liquid crystal display element can be further improved.

In addition, when the iminium ratio of the polymer (A) in the liquid crystal alignment agent is 30 to 90% (Examples 8 to 13, 15), the environmental resistance of the liquid crystal display element can be further improved.

In summary, in the liquid crystal alignment agent of the present invention, the diamine component (b) in the mixture forming the polymer (A) includes at least one diamine compound (b1) represented by the formula (b1-1). Therefore, the environmental resistance of the liquid crystal display element can be improved.

On the other hand, in the liquid crystal alignment agent of the present invention, the diamine component (b) in the mixture forming the polymer (A) further includes a diamine compound having a carboxylic acid group and represented by the formula (b2-1). (B2), and further improves the environmental resistance of the liquid crystal display element, and is therefore suitable for manufacturing a liquid crystal alignment film and a liquid crystal display element.

Although the present invention has been disclosed as above with the examples, it is not intended to limit the present invention. Any person with ordinary knowledge in the technical field can make some modifications and retouching without departing from the spirit and scope of the present invention. The protection scope of the present invention shall be determined by the scope of the attached patent application.

100‧‧‧LCD display element

110‧‧‧ Unit 1

112‧‧‧First substrate

114‧‧‧The first conductive film

116‧‧‧The first liquid crystal alignment film

120‧‧‧ Unit 2

122‧‧‧Second substrate

124‧‧‧Second conductive film

126‧‧‧Second LCD alignment film

130‧‧‧LCD unit

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

Claims (13)

A liquid crystal alignment agent includes: a polymer (A); and a solvent (B), wherein the polymer (A) is selected from the group consisting of a polyimide polymer, a polyimide polymer, and a polyimide system. A block copolymer or any combination of the aforementioned polymers; the polymer (A) comprises a unit represented by formula (b1-0): Formula (b1-0) In formula (b1-0), R ^a and R ^b each independently represent a single bond or a straight or branched chain alkyl group having 1 to 10 carbon atoms; Y is -O-, -COO-, -CONR ^c -or -NR ^c- ; R ^c is H or a linear or branched alkyl group having 1 to 3 carbon atoms; Cy is an alicyclic heterocyclic ring or an alicyclic heterocyclic ring containing a substituent; * is At the bonding point, the substituent of the alicyclic heterocyclic ring containing a substituent is a straight or branched alkyl group having 1 to 6 carbon atoms, an aromatic ring or an alicyclic ring. The liquid crystal alignment agent according to item 1 of the scope of patent application, wherein the polymer (A) includes a carboxylic acid group. The liquid crystal alignment agent according to item 1 of the scope of patent application, wherein the fluorinated rate of the polymer (A) is 30 to 90%. A liquid crystal alignment film is formed by using the liquid crystal alignment agent according to any one of claims 1 to 3 of a patent application scope. A liquid crystal display element includes the liquid crystal alignment film described in item 4 of the scope of patent application. A method for manufacturing a liquid crystal alignment agent, which comprises mixing a polymer (A) and a solvent (B); wherein the polymer (A) comprises a tetracarboxylic dianhydride component (a) and a diamine component (B) is obtained by reacting a mixture; the diamine component (b) includes at least one diamine compound (b1) represented by formula (b1-1): Formula (b1-1) In formula (b1-1), R ^a and R ^b each independently represents a single bond or a linear or branched alkyl group having 1 to 10 carbon atoms; Y is -O-, -COO-, -CONR ^c -or -NR ^c- ; R ^c is H or a linear or branched alkyl group having 1 to 3 carbon atoms; Cy is an alicyclic heterocyclic ring or an alicyclic heterocyclic ring containing a substituent; said The substituent of the alicyclic heterocyclic ring containing a substituent is a linear or branched alkyl group having 1 to 6 carbon atoms, an aromatic ring or an alicyclic ring. The method for manufacturing a liquid crystal alignment agent according to item 6 of the scope of patent application, wherein the total mole number based on the diamine component (b) is 100 moles, and the formula (b1-1) is The amount of the diamine compound (b1) used is 5 to 35 moles. The method for manufacturing a liquid crystal alignment agent according to item 6 of the scope of patent application, wherein the diamine component (b) further includes a diamine compound (b2) having a carboxylic acid group and represented by the formula (b2-1). ): Formula (b2-1) In formula (b2-1), X represents an organic group having an aromatic ring having 6 to 30 carbon atoms; z1 represents an integer of 1 to 4. The method for manufacturing a liquid crystal alignment agent according to item 8 of the scope of patent application, wherein the diamine compound (b2) having a carboxylic acid group and represented by the formula (b2-1) is selected from the formula (b2-2) To at least one of the groups consisting of compounds represented by formula (b2-6): Formula (b2-2) (B2-3) (B2-4) Formula (b2-5) Formula (b2-6) In formulas (b2-2) to (b2-6), X ¹ and X ³ each independently represent a single bond, -CH _2- , -C ₂ H _4- , -C (CH ₃ ) _2- , -CF _2- , -C (CF ₃ ) _2- , -O-, -CO-, -NH-, -N (CH ₃ )-, -CONH-, -NHCO-, -CH ₂ O- , -OCH _2- , -COO-, -OCO-, -CON (CH ₃ )-or -N (CH ₃ ) CO-; X ² represents a linear or branched alkyl group having a carbon number of 1 to 5; z2 And z8 each independently represent an integer from 1 to 4; z3 and z4 each independently represent an integer from 0 to 4; and (z3 + z4) represents an integer from 1 to 4; z5, z6 and z7 each independently represent an integer from 1 to 5. The method for manufacturing a liquid crystal alignment agent according to item 8 of the scope of patent application, wherein the total mole number based on the diamine component (b) is 100 moles, and the carboxylic acid group is represented by formula (b2) The amount of the diamine compound (b2) shown in -1) is 30 to 90 moles. According to the method for manufacturing a liquid crystal alignment agent according to item 6 of the scope of the patent application, wherein the polymer (A) has an imidization ratio of 30 to 90%. A method for manufacturing a liquid crystal alignment film is formed of a liquid crystal alignment agent prepared by the method for manufacturing a liquid crystal alignment agent according to any one of claims 6 to 11 of a patent application scope. A liquid crystal display element includes the liquid crystal alignment film prepared by the method for manufacturing a liquid crystal alignment film according to item 12 of the scope of patent application.