TWI687457B - Liquid crystal alignment agent and use thereof - Google Patents

Abstract

The invention relates to a liquid crystal alignment agent comprising a polymer (A) and a solvent (B); wherein the polymer (A) is selected from the group consisting of a polyamide acid polymer, a polyimide polymer, a polyimide-based block copolymer and a combination thereof. The liquid crystal alignment agent is capable of forming a liquid crystal alignment film with excellent pretilt angle stability. Furthermore, the invention also provides a liquid crystal alignment film made by the liquid crystal alignment agent as mentioned above, a method for forming a liquid crystal alignment film and a liquid crystal display element comprising the liquid crystal alignment film.

Description

Liquid crystal alignment agent and its application

The invention relates to a liquid crystal alignment agent and its application, in particular to a liquid crystal alignment agent capable of forming a liquid crystal alignment film with good pretilt stability, a liquid crystal alignment film formed by the liquid crystal alignment agent, and a liquid crystal having the liquid crystal alignment film Display element.

Since consumers' requirements for wide viewing angle characteristics of liquid crystal displays are increasing year by year, the electrical characteristics or display characteristics of liquid crystal display elements with wide viewing angles are more stringent than ever.

Nowadays, the vertical alignment type is the most widely used liquid crystal display element. In the vertical alignment type liquid crystal display element, the liquid crystal alignment film is used to arrange the liquid crystal molecules regularly, and the liquid crystal molecules can have a large tilt angle without providing an electric field, in order to improve the electrical or display characteristics of the vertical alignment type liquid crystal display element , Liquid crystal alignment film has become one of the important research objects. The formation method of the liquid crystal alignment film is usually formed by applying a liquid crystal alignment agent containing a polymer material such as a polyamic acid polymer, a polyimide polymer and the like to a substrate surface, and then forming the film after heat treatment and alignment treatment.

For example, Japanese Patent Laid-Open No. 2002-162630 discloses a polyamic acid polymer used for a liquid crystal alignment film of a vertical alignment type liquid crystal display element, which is composed of a diamine compound represented by formula (i) and a tetracarboxylic acid The dianhydride compound is obtained through polymerization.

In the formula, T, U and V are each independently a benzene ring or a cyclohexane ring, and any H on the ring may be an alkyl group having 1 to 3 carbon atoms, an alkyl group having 1 to 3 carbon atoms and substituted with fluorine, F , Cl or CN substitution; m and n are each independently an integer from 0 to 2; h is an integer from 0 to 5; R is H, F, Cl, CN or a monovalent organic group; m is 2 or n is 2 , 2 U or 2 V can be the same or different.

At this stage, with the high definition of liquid crystal display elements, and the requirement to reduce the contrast of the liquid crystal display elements or reduce the residual image charge, the use of liquid crystal alignment films must increase the voltage maintenance rate or reduce the residual charge when DC voltage is applied And/or the characteristics of prematurely mitigating the residual charge accumulated due to the DC voltage also gradually become important.

In order to improve the high voltage maintenance rate and reduce the residual image charge accumulated due to DC voltage as early as possible even after long-term exposure at high temperature, it is known to use polyacrylic acid and/or polyimide, which can be used as the polyacrylic acid The liquid crystal alignment agent of the diamine compound used for the raw materials of amine acid and polyimide (for example, refer to Patent Cooperation Treaty International Publication No. WO2009093704).

However, in recent years, large-screen and high-definition LCD TVs have been widely used. Among these applications, liquid crystal display elements must be used in harsh environments under the strict use environment compared with the previous display applications that mainly display text or still pictures. The characteristics of good pretilt stability.

Therefore, how to provide a liquid crystal alignment agent for a liquid crystal alignment film with good pretilt stability so that the formed liquid crystal alignment film can have a better display quality when applied to a liquid crystal display element is really urgent for those skilled in the art solved problem.

In the present invention, a liquid crystal alignment agent is obtained by providing a special polymer component. The liquid crystal alignment film and the liquid crystal display element formed by the liquid crystal alignment agent have the advantages of good pretilt angle stability.

Therefore, the present invention relates to a liquid crystal alignment agent, which comprises: a polymer (A); and a solvent (B); wherein, the polymer (A) is selected from the group consisting of a polyamic acid polymer and a polyimide polymer , A group consisting of a polyimide block copolymer and any combination of the above polymers; and the polymer (A) includes units represented by formula (Ia):

In formula (Ia), Y is a single bond, -COO-, -CONR _d -or -NR _d -; _Rd is a hydrogen atom, or a linear or branched alkyl group of C ₁ to C ₁₀ ; Ra is _a single Bond or C ₁ to C ₁₀ straight or branched chain alkyl; Ht is a nitrogen-containing heterocyclic ring; R _b is C ₁ to C ₁₀ straight or branched chain oxyalkyl, nitrile or carbonyl; R _c is C ₁ to C ₁₀ straight or branched chain alkyl; or R _b and R _c may combine with each other to form a single ring; a1 is an integer of 0 to 2; and * is a bond.

The present invention further provides a liquid crystal alignment film, which is manufactured by the aforementioned liquid crystal alignment agent.

The present invention also provides a liquid crystal display device including the aforementioned liquid crystal alignment film.

The invention also provides a method for manufacturing a liquid crystal alignment agent, which comprises a mixed polymer (A) and a solvent (B).

The invention also provides a method for manufacturing a liquid crystal alignment film, which comprises forming the liquid crystal alignment film by a liquid crystal alignment agent, wherein the liquid crystal alignment agent is composed of the aforementioned liquid crystal alignment agent Formed by the manufacturing method of the agent.

The present invention further provides a method for manufacturing a liquid crystal display element, the liquid crystal display element comprising a liquid crystal alignment film, the manufacturing method comprises forming the liquid crystal alignment film from a liquid crystal alignment agent, wherein the liquid crystal alignment agent is composed of the aforementioned liquid crystal alignment agent Formed by the manufacturing method.

100: liquid crystal display element

110: Unit 1

112: the 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 liquid crystal alignment film

130: LCD unit

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

The invention provides a liquid crystal alignment agent, which comprises: a polymer (A); and a solvent (B); wherein, the polymer (A) is selected from the group consisting of a polyamic acid polymer, a polyimide polymer, and a polyamide A group consisting of any combination of imine-based block copolymers and the above polymers; and the polymer (A) includes units represented by formula (Ia):

In formula (Ia), Y is a single bond, -COO-, -CONR _d -or -NR _d -; _Rd is a hydrogen atom, or a linear or branched alkyl group of C ₁ to C ₁₀ ; Ra is _a single Bond or C ₁ to C ₁₀ straight or branched chain alkyl; Ht is a nitrogen-containing heterocyclic ring; R _b is C ₁ to C ₁₀ straight or branched chain oxyalkyl, nitrile or carbonyl; R _c is C ₁ to C ₁₀ straight or branched chain alkyl; or R _b and R _c may combine with each other to form a single ring; a1 is an integer of 0 to 2; and * is a bond.

The polymer (A) according to the present invention is obtained by reacting a mixture including the tetracarboxylic dianhydride component (a) and the diamine component (b).

Specifically, the polymer (A) is selected from a polyamic acid polymer, a polyimide polymer, a polyimide block copolymer, or any combination of the above polymers. Wherein, the polyimide block copolymer is selected from polyamic acid block copolymer, polyimide block copolymer, polyamic acid-polyimide block copolymer or Any combination of the above polymers.

The polymer (A) contains units represented by formula (Ia):

In formula (Ia), Y is a single bond, -COO-, -CONR _d -or -NR _d -; _Rd is a hydrogen atom, or a linear or branched alkyl group of C ₁ to C ₁₀ ; Ra is _a single Bond or C ₁ to C ₁₀ straight or branched chain alkyl; Ht is a nitrogen-containing heterocyclic ring; R _b is C ₁ to C ₁₀ straight or branched chain oxyalkyl, nitrile or carbonyl; R _c is C ₁ to C ₁₀ straight or branched chain alkyl; or R _b and R _c may combine with each other to form a single ring; a1 is an integer of 0 to 2; and * is a bond.

Preferably, the polymer (A) comprises units represented by formula (Ia-1), formula (Ia-1) or formula (Ia-3):

Y is a single bond, -COO-, -CONR _d -or -NR _d -; R _d is a hydrogen atom, or a linear or branched alkyl group of C ₁ to C ₁₀ ; Ra is _a single bond or C ₁ to C ₁₀ linear or branched alkyl; R _b is C ₁ to C ₁₀ linear or branched oxyalkyl, nitrile or carbonyl; R _c is C ₁ to C ₁₀ linear or branched alkyl; Or R _b and R _c may combine with each other to form a single ring; a1 is an integer of 0 to 2; and * is a bond.

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

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

Specific examples of the alicyclic tetracarboxylic dianhydride compound may include, but are not limited to, 1,2,3,4-cyclobutane tetracarboxylic 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 tetracarboxylic dianhydride, 1,2,3,4-tetramethyl-1,2,3,4-cyclobutane tetracarboxylic dianhydride, 1,2,3,4-cyclopentane tetra Carboxylic 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 acid dianhydride, bicyclo[2.2.2]-octyl -7-ene-2,3,5,6-tetracarboxylic dianhydride or a combination of the above compounds.

Specific examples of the aromatic tetracarboxylic dianhydride compound may include, but are not limited to, 3,4-dicarboxy-1,2,3,4-tetrahydronaphthalene-1-succinic dianhydride and pyromellitic dianhydride , 3,3',4,4'-benzophenone tetracarboxylic dianhydride, 3,3',4,4'-biphenyl tetracarboxylic dianhydride, 1,4,5,8-naphthalene tetra Carboxylic dianhydride, 2,3,6,7-naphthalene tetracarboxylic dianhydride, 3,3'-4,4'-diphenylethane tetracarboxylic 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)diphenyl sulfide dianhydride, 4,4'-bis(3,4-dicarboxyphenoxy)diphenyl dianhydride, 4,4' -Bis(3,4-dicarboxyphenoxy)diphenylpropane dianhydride (4,4'-bis(3,4-dicarboxy phenoxy)diphenylpropane dianhydride), 3,3',4,4'-perfluoroiso Propylenediphthalic dianhydride, 3,3',4,4'-diphenyltetracarboxylic dianhydride, bis(phthalic acid) benzenephosphine oxide dianhydride, p-phenylene-bis( Triphenyl phthalic acid) dianhydride, m-phenylene-bis (triphenyl phthalic acid) dianhydride, bis (triphenyl phthalic acid) -4,4'-diphenyl ether dianhydride, Bis(triphenylphthalic acid)-4,4'-diphenylmethane dianhydride, ethylene glycol-bis (dehydrated trimellitate), propylene glycol-bis (dehydrated trimellitate), 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(anhydride trimellitate), 2,3,4,5-tetrahydrofuran tetracarboxylic dianhydride, 1,3,3a,4,5 ,9b-Hexahydro-5-(tetrahydro-2,5-bi- pendant-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-bi- pendant-3-furanyl)-naphtho[1,2-c]-furan-1,3 -Diketone, 1,3,3a,4,5,9b-hexahydro-5-ethyl-5-(tetrahydro-2,5-dipentoxy-3-furanyl)-naphtho[1, 2-c)-furan-1,3-dione, 1,3,3a,4,5,9b-hexahydro-7-methyl-5-(tetrahydro-2,5-di Pendant-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-furanyl)-naphtho[1,2-c]-furan-1,3-dione, 1,3,3a,4,5,9b -Hexahydro-8-methyl-5-(tetrahydro-2,5-bi- pendant-3-furanyl)-naphtho[1,2-c]-furan-1,3-dione, 1 ,3,3a,4,5,9b-hexahydro-8-ethyl-5-(tetrahydro-2,5-bi- pendant-3-furanyl)-naphtho[1,2-c]- Furan-1,3-dione, 1,3,3a,4,5,9b-hexahydro-5,8-dimethyl-5-(tetrahydro-2,5-bi- pendant-3-furan Group)-naphtho[1,2-c]-furan-1,3-dione, 5-(2,5-bi- pendant tetrahydrofuranyl)-3-methyl-3-cyclohexene-1, Aromatic tetracarboxylic dianhydride compounds such as 2-dicarboxylic dianhydride or a combination of the above compounds.

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

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 each may independently represent —H or an alkyl group. Specific examples of the tetracarboxylic dianhydride compound represented by formula (a-5) include at least one of the compounds represented by formula (a-5-1) to formula (a-5-3).

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 alkyl. The tetracarboxylic dianhydride compound represented by formula (a-6) is preferably a compound represented by formula (a-6-1).

Preferably, the tetracarboxylic dianhydride component (a) includes but is not limited to 1,2,3,4-cyclobutane tetracarboxylic dianhydride, 1,2,3,4-cyclopentane tetracarboxylic dianhydride Anhydride, 2,3,5-tricarboxycyclopentylacetic acid dianhydride, 1,2,4,5-cyclohexanetetracarboxylic dianhydride, 3,4-dicarboxy-1,2,3,4-tetra Hydronaphthalene-1-succinic dianhydride, pyromellitic dianhydride, 3,3',4,4'-benzophenone tetracarboxylic dianhydride and 3,3',4,4'-biphenyl Tetracarboxylic dianhydride. The tetracarboxylic dianhydride component (a) can be used alone or in combination.

Based on the total usage of the diamine component (b) being 100 moles, the usage quantity of the tetracarboxylic dianhydride component (a) is preferably 80 to 120 moles, more preferably 85 to 115 moles ear.

The diamine component (b) according to the present invention includes at least one diamine compound (b1) represented by formula (Ib):

In formula (Ib), Y is a single bond, -COO-, -CONR _d -or -NR _d -; _Rd is a hydrogen atom, or a linear or branched alkyl group of C ₁ to C ₁₀ ; Ra is _a single Bond or C ₁ to C ₁₀ straight or branched chain alkyl; Ht is a nitrogen-containing heterocyclic ring; R _b is C ₁ to C ₁₀ straight or branched chain oxyalkyl, nitrile or carbonyl; R _c is C ₁ to C ₁₀ straight or branched chain alkyl; or R _b and R _c may be combined with each other to form a single ring; and a1 is an integer of 0 to 2.

Preferably, the diamine component (b) comprises the diamine compound (b1) represented by formula (Ib-1), formula (Ib-2) or formula (Ib-3):

Where Y is a single bond, -COO-, -CONR _d -or -NR _d -; R _d is a hydrogen atom, or a linear or branched alkyl group of C ₁ to C ₁₀ ; Ra is _a single bond or C ₁ to C linear or branched alkyl group of _10; R _b is a C ₁ to C ₁₀ straight chain or branched chain of oxyalkyl, nitrile group or carbonyl group; R _c is a C linear or branched alkyl of ₁ to ₁₀ C Group; or R _b and R _c may combine with each other to form a single ring; and a1 is an integer of 0 to 2.

、

A specific example of the diamine compound (b1) is

,

In a specific example of the present invention, based on the total usage of the diamine component (b) is 100 moles, the usage of the diamine compound (b1) is 3 to 40 moles, preferably 5 to 35 moles Ears, more preferably 5 to 30 moles.

When the monomer for polymerization of the polymer (A) does not contain the diamine compound (b1), the prepared liquid crystal alignment agent has a defect that the stability of the pretilt angle is not good. When the amount of the diamine compound (b1) used is within the above range, a liquid crystal display device with excellent pretilt stability can be obtained.

Preferably, the diamine component (b) of the present invention may further contain other diamine compounds (b2).

The other diamine compound (b2) includes an aliphatic diamine compound, an alicyclic diamine compound, an aromatic diamine compound, a diamine compound having formula (b2-1) to formula (b2-26), 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 Alkanes, 1,6-diaminohexane, 1,7-diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane, 1,10-diaminodecane Alkane, 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, or a combination of the above compounds.

Specific examples of the alicyclic diamine compound include but are not limited to 4,4'-diaminodicyclohexylmethane, 4,4'-diamino-3,3'-dimethyldicyclohexylamine, 1 ,3-diaminocyclohexyl Alkanes, 1,4-diaminocyclohexane, isophorone diamine, tetrahydrodicyclopentadiene diamine, tricyclo[6.2.1.02,7]-undecene dimethyl diamine, 4,4'-methylenebis (cyclohexylamine), or a combination of the above compounds.

Specific examples of the aromatic diamine compound include but are not limited to 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylethane, and 4,4'-diaminodiphenyl Benzene, 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 indanyl dimethylene diamine, 3,3'-diaminobenzophenone, 3,4'-diamine 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 ] 碸, 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-diamino stilbene, 9,9-bis(4-aminophenyl) stilbene, 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 Yl)phenyl]hexafluoropropane, 4,4'-bis[(4-amino-2-trifluoromethyl)phenoxy]-octafluorobiphenyl, 5-[4-(4-n-pentane 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.

The diamine compounds having formula (b2-1) to formula (b2-26) are shown below.

、

、

、

B²表示具有甾(膽固醇(steroid))骨架的基、三氟甲基、氟基、碳數為2至30的烷基、或衍生自吡啶、嘧啶、三嗪、哌啶或哌嗪等含氮原子環狀結構的一價基團。 In formula (b2-1), B ¹ represents -O-,

,

,

,

B ² represents a group having a steroid (cholesterol) skeleton, a trifluoromethyl group, a fluoro group, an alkyl group having a carbon number of 2 to 30, or derived from pyridine, pyrimidine, triazine, piperidine, or piperazine. The monovalent group of nitrogen atom ring structure.

Specific examples of the compound represented by formula (b2-1) include, but are not limited to, 2,4-diaminophenyl ethyl formate, 2,3,5-diaminophenyl ethyl formate Ester (3,5-diaminophenyl ethyl formate), 2,4-diaminophenyl propyl 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-hexadecyloxy-2,4-diaminobenzene ( 1-hexadecoxy-2,4-diaminobenzene), 1-octadecoxy-2,4-diaminobenzene (1-octadecoxy-2,4-diaminobenzene), from formula (b2-1-1) to formula At least one of the compounds represented by (b2-1-6), or a combination of the above compounds.

The compounds represented by formula (b2-1-1) to formula (b2-1-6) are shown below.

In the formula (B2-2), and B ¹ in the formula (b2-1) B same as ^1, B ³ and B ⁴ each independently represents a divalent aliphatic ring, a divalent aromatic ring or a divalent 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, a fluoroalkoxy group having 1 to 5 carbon atoms, a cyano group, or Halogen atom.

Specific examples of the compound represented by formula (b2-2) include at least one of the compounds represented by the following formula (b2-2-1) to formula (b2-2-13):

In formula (b2-2-1) to formula (b2-2-13), s represents an integer of 3 to 12.

In formula (b2-3), B ⁶ each independently represents a hydrogen atom, an acetyl group having 1 to 5 carbon atoms, an alkyl group having 1 to 5 carbon atoms, an alkoxy group or a halogen atom having 1 to 5 carbon atoms, 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 formula (b2-3) include when u is 1: p-diamine, m-diamine, o-diamine, or 2,5-diaminotoluene, etc.; 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, etc.

Specific examples of the compound represented by formula (b2-3) preferably include p-diaminobenzene, 2,5-diaminotoluene, 4,4'-diaminobiphenyl, 3,3'-dimethyl Oxy-4,4'-diaminobiphenyl, 1,4-bis(4'-aminophenyl)benzene or a combination of the above compounds.

In formula (b2-4), v represents an integer of 2 to 12.

In formula (b2-5), w represents an integer of 1 to 5.

The compound represented by formula (b2-5) is preferably 4,4'-diamino-diphenyl sulfide.

In formula (b2-6), 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 derived from pyridine, pyrimidine, triazine, piperidine or piper A divalent group of a ring structure containing a nitrogen atom such as azine.

In formula (b2-7), B ¹⁰ , B ¹¹ , B ¹² and B ¹³ each independently represent a hydrocarbon group having 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; and x2 represents an integer of 1 to 20.

In formula (b2-8), B ¹⁴ represents an oxygen atom or cyclohexane group; B ¹⁵ represents a methylene group; B ¹⁶ represents a phenyl group or cyclohexane group; and B ¹⁷ represents a hydrogen atom or heptyl group.

Specific examples of the compound represented by formula (b2-8) include the compound represented by formula (b2-8-1), the compound represented by formula (b2-8-2), or a combination of the above compounds:

The compounds represented by formula (b2-9) to formula (b2-25) are shown below.

In formula (b2-17) to formula (b2-25), B ¹⁸ preferably represents an alkyl group having 1 to 10 carbon atoms or an alkoxy group having 1 to 10 carbon atoms; B ¹⁹ preferably represents a hydrogen atom , An alkyl group having 1 to 10 carbon atoms or an alkoxy group having 1 to 10 carbon atoms.

In formula (b2-26), B ²⁰ and B ²² 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 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 (b2-26), 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 with a diaminophenyl group.). The group represented by "-C _f H _2f+1 "is preferably linear. The position of the two amine groups in the diaminophenyl group with respect to other groups is preferably the 2,4 position or the 3,5 position.

Specific examples of the compound represented by formula (b2-26) include compounds represented by the following formula (b2-26-1) to formula (b2-26-4):

The other diamine component (b2) can be used alone or in combination.

Specific examples of the other diamine component (b2) preferably include, but are not limited to 1,2-diaminoethane, 4,4'-diaminodicyclohexylmethane, and 4,4'-diamine Diphenylmethane, 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- Ethyl diaminophenylcarboxylate, 1-octadecyloxy-2,4-diaminobenzene, compound represented by formula (b2-1-1), represented by formula (b2-1-2) Compound, compound represented by formula (b2-2-1), compound represented by formula (b2-2-11), p-diamine benzene, m-diamine benzene, o-diamine benzene, compound represented by formula (b2 -8-1), or a combination of the above compounds.

In a specific example of the present invention, based on the total usage of the diamine component (b) is 100 moles, the usage of the other diamine compound (b2) is 60 to 97 moles, preferably 65 to 95 Molar, more preferably 70 to 95 mol.

The polymer (A) may include at least one of polyamic acid and polyimide. In addition, the polymer (A) may further include a polyimide block copolymer. The following further describes the preparation methods of the above-mentioned various polymer compositions.

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 polymerizes at a temperature of 0°C to 100°C Condensation reaction. After the reaction for 1 hour to 24 hours, the reaction solution is distilled under reduced pressure with an evaporator to obtain polyamide. Alternatively, the reaction solution is poured into a large amount of lean solvent to obtain a precipitate. Next, the precipitate is dried under reduced pressure to obtain polyamide.

Based on the usage amount of the diamine component (b) is 100 moles, the usage amount of the tetracarboxylic dianhydride component (a) is 20 moles to 200 moles; more preferably, the tetracarboxylic dianhydride The amount of component (a) used is 30 mol 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, for example: N-methyl-2-pyrrolidinone (N-methyl-2-pyrrolidinone; NMP), N,N-dimethylacetamide, Aprotic polar solvents such as N,N-dimethylformamide, dimethylsulfoxide, γ-butyrolactone, tetramethylurea, or hexamethyltriphosphate; or (2) Phenolic solvents, for example, phenolic solvents such as m-cresol, xylenol, phenol or halogenated phenols. Based on the total amount of the mixture used is 100 parts by weight, the 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.

It is worth noting that in the polycondensation reaction, an appropriate amount of lean solvent can be used in combination, and the lean solvent will not cause precipitation of the polyamic acid. The poor solvent can be used alone 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 such as alcohol or triethylene glycol; (2) ketones, such as ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; (3) esters, such as: 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 dimethyl ether Ethers such as basic 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. The use amount of the diamine component (b) is 100 parts by weight, and the use amount of the poor solvent is preferably 0 to 60 parts by weight, and more preferably 0 to 50 parts by weight.

The method for preparing polyimide is obtained by heating the polyamic acid prepared by the method for preparing polyamic acid in the presence of a dehydrating agent and a catalyst. During the heating process, the amide acid functional group in the polyamic acid can be converted into the amide imine functional group (ie, imidate) via a dehydration ring-closure reaction.

The solvent used in the dehydration ring-closure 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 base polyamino acid is 100 parts by weight, and the amount of the solvent used in the dehydration ring-closing reaction is preferably 200 parts by weight to 2000 parts by weight, and More preferably, it is 300 parts by weight to 1800 parts by weight.

In order to obtain a better degree of polyamide imidization of the polyamic acid, the operating temperature of the dehydration ring-closing reaction is preferably 40°C to 200°C, more preferably 40°C to 150°C. If the operating temperature of the dehydration and ring-closing reaction is lower than 40°C, the imidate reaction is incomplete, and the degree of amidate of the polyamic acid is reduced. However, if the operating temperature of the dehydration ring-closure reaction is higher than 200°C, the weight average molecular weight of the resulting polyimide is low.

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

In a specific example of the present invention, the imidate ratio of the polymer composition (A) is 35% to 85%, preferably 40% to 85%, and more preferably 40% to 80%. When the imidate ratio of the polymer composition (A) is within the above range, a liquid crystal display device with excellent stability of pretilt angle can be obtained.

The polyimide block copolymer is selected from the group consisting of polyamic acid block copolymers, polyimide block copolymers, polyamic acid-polyimide block copolymers or the above polymerization Any combination of objects.

The method for preparing the polyimide block copolymer is preferably to first dissolve the starting material in a solvent and perform a polycondensation reaction, where the starting material includes at least one polyamic acid and/or at least one polyacrylic acid Imine, and may further include tetracarboxylic dianhydride component (a) and diamine component (b).

The tetracarboxylic dianhydride component and the diamine component in the starting material 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 The solvent in the polycondensation reaction may be the same as the solvent (B) in the liquid crystal alignment agent described below, which will not be repeated here.

The 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 amount of the starting material used is 100 parts by weight. 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 acid with different terminal groups and different structures; (2) two kinds of polyimide with different terminal groups and different structures; (3 ) Polyamide and polyimide with different terminal groups and different structures; (4) Polyamide, tetracarboxylic dianhydride component and diamine component, among which the tetracarboxylic dianhydride component At least one of the diamine components is different from the structure of the tetracarboxylic dianhydride component and the diamine component used to form the polyamic acid; (5) the polyimide and tetracarboxylic dianhydride groups 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) Polyamide, polyimide, tetracarboxylic dianhydride component and diamine component, wherein at least one of tetracarboxylic dianhydride component and diamine component forms polyamide The structure of the tetracarboxylic dianhydride component used in the acid or polyimide is different from that of the diamine component; (7) Two different structures of the polyamic acid, tetracarboxylic dianhydride component and diamine Component; (8) two different structures of polyimide, tetracarboxylic dianhydride component and diamine component; (9) two types of polyamic acid with terminal structure of acid anhydride group and different structure and Diamine component; (10) Two kinds of polyamic acid and tetracarboxylic dianhydride with different amine groups and different structures; (11) Two kinds of polyacrylic acid with different structure and acid groups Imine and diamine components; or (12) Polyimide and tetracarboxylic dianhydride components whose two terminal groups are amine groups and have different structures.

Within the range that does not affect the efficacy of the present invention, the polyamic acid, polyimide, and polyimide-based block copolymer are preferably terminal modified polymers after molecular weight adjustment. The use of terminal-modified polymers can improve the application of liquid crystal alignment agents performance. The method for preparing the terminal-modified polymer can be obtained by adding a monofunctional compound while the polyamic acid undergoes 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-decyl succinic anhydride, n-dodecyl succinic anhydride, n-fourteen 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-icosaneamine; 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-converted weight average molecular weight measured by Gel Permeation Chromatography (GPC) of 2,000 to 200,000, preferably 3,000 to 100,000, more preferably 4000 to 50000.

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, preferably the same as in the aforementioned synthetic polyamide At the same time, the solvent used can also be used in combination with the poor solvent used in the synthesis of the polyamide.

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, ethylenedioxide Alcohol 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 Ester or N,N-dimethylformamide or N,N-dimethylacetamide (N,N-dimethyl acetamide) etc. The solvent (B) can be used alone or in combination.

The use amount of the polymer (A) is 100 parts by weight, and the use amount of the solvent (B) is 800 to 2500 parts by weight, preferably 1000 to 2200 parts by weight, and more preferably 1000 to 2000 parts by weight.

The liquid crystal alignment agent may optionally add an additive (C) within a range that does not affect the efficacy of the present invention, where the additive (C) includes an epoxy compound, a silane compound having a functional group, or a combination thereof. The additive (C) is used to improve the adhesion of the liquid crystal alignment film to the substrate surface.

The epoxy compound includes but is not limited to ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, polypropylene glycol dicyclic Oxypropyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerol diglycidyl ether, 2,2-dibromo neopentyl glycol Diglycidyl ether, 1,3,5,6-tetraglycidyl-2,4-hexanediol, N,N,N',N'-tetraglycidyl-m-xylene Amine, 1,3-bis(N,N-diglycidoxypropylaminomethyl)cyclohexane, N,N,N',N'-tetraglycidoxy-4,4'-diamino Diphenylmethane, 3-(N,N-diepoxypropyl)aminopropyltrimethoxysilane, or a combination of the above compounds.

The epoxy compound can be used alone or in combination.

Based on the use amount of the polymer (A) is 100 parts by weight, the use amount of the epoxy compound may be 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 -Aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropyl Methyldimethoxysilane, 3-ureidopropyltrimethoxy silane, 3-ureidopropyltriethoxysilane, N-ethoxycarbonyl-3-aminopropyl Trimethoxysilane, N-ethoxycarbonyl-3-aminopropyltriethoxysilane, N-triethoxysilylpropyltriethylene Amine, N-trimethoxysilylpropyltriethylenetriamine, 10-trimethoxysilyl-1,4,7-triacdecane, 10-triethoxysilyl-1,4,7 -Triacdecane, 9-trimethoxysilyl-3,6-diazonyl acetate, 9-triethoxysilyl-3,6-diazonyl acetate, N-benzyl- 3-aminopropyltrimethoxysilane, N-benzyl-3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-phenyl-3 -Aminopropyltriethoxysilane, N-bis(ethylene oxide)-3-aminopropyltrimethoxysilane, N-bis(ethylene oxide)-3-aminopropyltriethoxysilane, Or a combination of the above compounds.

The silane compound having a functional group can 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) is 100 parts by weight.

Based on the use amount of the polymer (A) is 100 parts by weight, 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.

<Manufacturing method of liquid crystal alignment agent>

The manufacturing method of the liquid crystal alignment agent is not particularly limited, and can be prepared by a general mixing method. For example, the tetracarboxylic dianhydride component (a) and the diamine component (b) are mixed uniformly to react to form a polymer (A). Next, the polymer (A) is added to the solvent (B) under the condition of a temperature of 0° C. to 200° C., and the additive (C) may be optionally added, and the stirring device may be continuously stirred until it is dissolved. Preferably, the solvent (B) is added to the polymerization composition 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, 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 the liquid crystal alignment agent on the surface of the 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. Next, the precoat layer is subjected to pre-bake treatment, post-bake treatment, and alignment treatment to prepare 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, and more preferably 40°C to 110°C, and particularly preferably 50°C to 100°C.

There is no particular limitation on the alignment treatment. The cloth made of fibers such as nylon, rayon, or cotton can be wrapped around the drum and rubbed in a certain direction for alignment.

The purpose of the post-baking treatment step is to further subject the polymer in the pre-coating layer to dehydration ring-closure (amidation) reaction. The operating temperature of the post-baking treatment is preferably 150°C to 300°C, more preferably 180°C to 280°C, and particularly preferably 200°C to 250°C.

<Liquid crystal display element and its manufacturing method>

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

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 separated 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 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 In the liquid crystal alignment film 126, 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 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, etc., wherein the transparent materials include, but are not limited to, alkali-free glass, soda lime glass, hard glass (Pales glass), quartz glass used for liquid crystal display devices , Polyethylene terephthalate, polybutylene terephthalate, polyether ash 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 cell 130 form a pretilt 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. This electric field can drive the liquid crystal cell 130, thereby changing the arrangement of the liquid crystal molecules in the liquid crystal cell 130.

The liquid crystals used in the liquid crystal unit 130 may be used alone or in combination. The liquid crystals include but are not limited to diaminobenzene-based liquid crystals, pyridazine-based liquid crystals, shiff base-based liquid crystals, and azo-based ( Azoxy-based liquid crystal, biphenyl-based liquid crystal, phenylcyclohexane-based liquid crystal, ester-based liquid crystal, terphenyl, terphenyl, biphenylcyclohexane-based liquid crystal, pyrimidine ( pyrimidine-based liquid crystal, dioxane-based liquid crystal, bicyclooctane-based liquid crystal or cubane-based liquid crystal, etc., and can be added according to demand, for example, cholesteryl chloride, cholesterol nonyl Cholesteric liquid crystals such as esters (cholesteryl nonanoate), cholesterol carbonates (cholesteryl carbonate), or chiral agents under the trade names "C-15" and "CB-15" (made by Merck) ,or It is a ferroelectric liquid crystal such as p-decyloxybenzylidene-p-amino-2-methylbutylcinnamate.

The following examples illustrate the invention in detail, but it does not mean that the invention is limited to what is disclosed by these examples.

[Preparation of polymer (A)] <Synthesis Example A-1-1>

A nitrogen inlet, stirrer, condenser, and thermometer are set on a four-necked conical flask with a volume of 500 ml, and nitrogen is introduced. Then, in a four-necked conical flask, add 0.0005 moles of b1-1 shown in Table 1, 0.037 moles of p-diamine (abbreviated as b2-1), and 0.0125 moles of b2 shown in Table 1. -6 and 80 grams of N-methyl-2-pyrrolidone (N-methyl-2-pyrrolidone, referred to as NMP), and stirred at room temperature until dissolved. Next, 0.05 mol of 2,3,5-tricarboxycyclopentylacetic dianhydride (abbreviated as a-1) and 20 g of NMP were added, and the reaction was carried out at room temperature for 2 hours. After the reaction was completed, the reaction solution was poured into 1500 ml of water to precipitate the polymer. Then, the obtained polymer was filtered, washed repeatedly with methanol and filtered three times, placed in a vacuum oven, and dried at a temperature of 60°C to obtain a polymer (A-1-1).

<Synthesis Examples A-1-2 to A-1-5>

Synthesis Examples A-1-2 to A-1-5 prepared the polymer in the same steps as Synthesis Example A-1-1, except that the type of tetracarboxylic dianhydride compound or diamine compound was changed And its usage is shown in Table 1.

<Synthesis Example A-2-1>

A nitrogen inlet, stirrer, condenser, and thermometer are set on a four-necked conical flask with a volume of 500 ml, and nitrogen is introduced. Then, in a four-necked conical flask, add 0.0015 moles of b1-1 shown in Table 1, 0.036 moles of p-diamine (abbreviated as b2-1), and 0.0125 moles of b2 shown in Table 1. -6 and 80 grams of N-methyl-2-pyrrolidone (N-methyl-2-pyrrolidone, referred to as NMP), and stirred at room temperature until dissolved. Next, join 0.05 moles of 2,3,5-tricarboxycyclopentylacetic dianhydride (abbreviated as a-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 the amide imidization reaction. After the reaction was completed, the reaction solution was poured into 1500 ml of water to precipitate the polymer. Then, the polymer obtained was filtered, washed repeatedly with methanol and filtered three times, placed in a vacuum oven, and dried at a temperature of 60°C to obtain a polymer (A-2-1).

<Synthesis Examples A-2-2 to A-2-12 and Comparative Synthesis Examples A-4-1 to A-4-5>

Synthesis Examples A-2-2 to A-2-12 and Comparative Synthesis Examples A-4-1 to A-4-5 were prepared in the same steps as Synthesis Example A-2-1, except for Lies in: changing the type and usage of tetracarboxylic dianhydride component, diamine component, dehydrating agent or catalyst, as shown in Table 1; and changing the type and usage of catalyst of dehydrating agent and dehydration ring-closing reaction the amount.

<Synthesis Example A-3-1>

A nitrogen inlet, stirrer, condenser, and thermometer are set on a four-necked conical flask with a volume of 500 ml, and nitrogen is introduced. Then, in a four-necked conical flask, 0.0325 moles of p-diamine (abbreviated as b2-1) and 40 grams of N-methyl-2-pyrrolidone (abbreviated as NMP), and stirred at room temperature until dissolved. Next, 0.025 moles of pyromellitic dianhydride (abbreviated as a-3) and 10 grams of NMP were added. After reacting at room temperature for 6 hours, 50 g of NMP, 1.3 g of acetic anhydride and 10 g of pyridine were added, the temperature was raised to 60° C., and stirring was continued for 2 hours to carry out the amide imidization reaction. After the reaction was completed, the reaction solution was poured into 1500 ml of water to precipitate the polymer. Then, the obtained polymer was filtered, washed repeatedly with methanol and filtered three times, placed in a vacuum oven, and dried at a temperature of 60°C to obtain a polymer (A-3-1-1).

A nitrogen inlet, stirrer, condenser, and thermometer are set on a four-necked conical flask with a volume of 500 ml, and nitrogen is introduced. Then, in a four-necked conical flask, add the above synthesized polymer (A-3-1-1), add 0.0075 moles b1-4 shown in Table 1, add 0.01 moles b1 shown in Table 1 -6, and 100 grams of NMP, and stirred at room temperature until dissolved. Pick up Then, 0.025 moles of 2,3,5-tricarboxycyclopentylacetic dianhydride (abbreviated as a-1) and 10 grams of NMP were added, and reacted at room temperature for 2 hours. After the reaction was completed, the reaction solution was poured into 1500 ml of water to precipitate the polymer. Then, the obtained polymer was filtered, washed repeatedly with methanol and filtered three times, placed in a vacuum oven, and dried at a temperature of 60°C to obtain a polymer (A-3-1).

In Table 1 and Table 2:

a1-1 2,3,5-tricarboxycyclopentyl acetic dianhydride

a1-2 1,2,3,4-cyclobutane tetracarboxylic dianhydride

a1-3 Benzenetetracarboxylic dianhydride

b1-1

b1-2

b1-3

b1-4

b1-5

b1-6

b1-7

b1-8

b2-1 p-diaminobenzene

b2-2 4,4'-diaminodiphenylmethane

b2-3 4,4'-diaminodiphenyl ether

b2-4

b2-5

b2-6

b2-7

b2-8

[Preparation of liquid crystal alignment agent, liquid crystal alignment film and liquid crystal display element] <Example 1>

100 parts by weight of polymer (A-1-1) and 800 parts by weight of N-methyl-2-pyrrolidone (abbreviated as B-1) were weighed, and stirred and mixed at room temperature to form the liquid crystal of Example 1. Alignment agent.

The liquid crystal alignment agent was evaluated for each test item, and the results are shown in Table 3.

<Examples 2 to 18 and Comparative Examples 1 to 5>

In Examples 2 to 18 and Comparative Examples 1 to 5, the liquid crystal alignment agent was prepared by the same procedure as in Example 1, except that the types and usage amounts of the polymer composition, solvent and additives were changed, as shown in the table 3 and 4 are shown. These liquid crystal alignment agents were evaluated for each test item, and the results are shown in Tables 3 and 4.

Table 3 and Table 4:

B-1 N-methyl-2-pyrrolidone

B-2 Ethylene glycol n-butyl ether

B-3 N,N-dimethylacetamide

C-1 N,N,N’,N’-tetraepoxypropyl-4,4’-diaminodiphenylmethane

C-2 3-aminopropyltriethoxysilane

[Test items] <Amidation rate>

The ratio of imidate refers to the ratio of the number of imidate rings calculated based on the total number of amide acid functional groups and the number of imidate rings in the polyimide polymer, and Expressed as a percentage.

The detection method of the imidate ratio is to dry the polymer (A) of the above Synthesis Examples A-1-1 to A-2-10 and Comparative Synthesis Examples A-3-1 to A-3-7 under reduced pressure Then, dissolve the aforementioned polymer (A) in an appropriate deuteration solvent (e.g. deuterated dimethyl sulfoxide) and use tetramethylsilane as the reference substance at room temperature (e.g. 25°C) The results of ¹ H-NMR (hydrogen atom nuclear magnetic resonance) were measured as follows, and the imidate ratio (%) of the polymer (A) was calculated by the following formula:

In the formula, △1 represents the peak area generated by the chemical shift of the NH matrix near 10 ppm, △2 represents the peak area of other protons, and α represents the polymer composition (A). The ratio of the number of one proton in the NH group in the polyamide precursor of other polymers to the number of other protons.

<Pretilt angle stability>

Apply the prepared liquid crystal alignment agent on the transparent electrode surface of the glass substrate containing ITO film (liquid crystal alignment film printer is manufactured by Nippon Photographic Printing Co., Ltd.), and heat on a hot plate at 80°C for 1 minute (pre-baking) After removing the solvent, heating on a hot plate at 150°C for 10 minutes (post-baking) can obtain a coating film with an average film thickness of 600Å. Put the coating film on The friction machine with man-made fiber cloth is wound at 400 rpm, 3 cm/sec traverse speed and 0.1 mm fiber length. After that, ultrasonic cleaning was performed in ultrapure water for 1 minute, followed by drying in a 100°C oven for 10 minutes to obtain a substrate with a liquid crystal alignment film. Repeat the previous steps to obtain a pair (2 pieces) of substrates with liquid crystal alignment films.

Then, after the outer edge of the substrate with the liquid crystal alignment film is coated with an epoxy resin adhesive filled with alumina balls with a diameter of 5.5 μm, the surface of the liquid crystal alignment film is relatively laminated, and the adhesive is hardened. Then, after filling the nematic liquid crystal (made by Merck, MLC-6608) from the liquid crystal injection port between the pair of substrates, the liquid crystal injection port is sealed with an acrylic photohardening adhesive to obtain Liquid crystal display element.

The above-prepared liquid crystal cell was measured with a pre-tilt angle measuring instrument (Optipro, manufactured by Shintech) to measure the initial pre-tilt angle, and the liquid crystal display element after the initial pre-tilt angle measurement was irradiated with a fluorescent lamp at an irradiation amount of 10,000 J/m ² at 60°C And the AC voltage applied to 20Vp-p for 20 hours is evaluated by the amount of pre-tilt angle change before and after, the evaluation criteria are as follows: ◎: pre-tilt angle change amount ≦1°; ○: 1°<pre-tilt angle change amount≦2° ; ×: Pretilt angle change> 2°.

The above-mentioned embodiments are only to illustrate the principle and efficacy of the present invention, but not to limit the present invention. Modifications and changes made by those skilled in the art to the above embodiments still do not violate the spirit of the present invention. The scope of the rights of the present invention shall be as listed in the patent application scope described later.

100‧‧‧LCD display element

110‧‧‧ Unit 1

112‧‧‧The first substrate

114‧‧‧ First conductive film

116‧‧‧The first liquid crystal alignment film

120‧‧‧ Unit 2

122‧‧‧Second substrate

124‧‧‧Second conductive film

126‧‧‧Second liquid crystal alignment film

130‧‧‧LCD unit

Claims (10)

A liquid crystal alignment agent, comprising: a polymer (A); and a solvent (B); wherein, the polymer (A) is selected from the group consisting of polyamic acid polymer, polyimide polymer, and polyimide block A group consisting of a copolymer and any combination of the above polymers; and the polymer (A) comprises units represented by formula (Ia-1), formula (Ia-2) or formula (Ia-3):

Y is a single bond, -COO-, -CONR _d -or -NR _d -; R _d is a hydrogen atom, or a linear or branched alkyl group of C ₁ to C ₁₀ ; Ra is _a single bond or C ₁ to C ₁₀ linear or branched alkyl; R _b is C ₁ to C ₁₀ linear or branched oxyalkyl, nitrile or carbonyl; R _c is C ₁ to C ₁₀ linear or branched alkyl; Or R _b and R _c may combine with each other to form a single ring; a1 is an integer of 0 to 2; and * is a bond. The liquid crystal alignment agent according to claim 1, wherein the imidate of the polymer (A) is 35% to 85%. A liquid crystal alignment film formed of the liquid crystal alignment agent according to claim 1 or 2. A liquid crystal display element comprising the liquid crystal alignment film according to claim 3. A method for manufacturing a liquid crystal alignment agent, comprising a mixed polymer (A) and a solvent (B); wherein the polymer (A) is selected from the group consisting of polyamido acid polymers, polyimide polymers, and polyimide systems Groups composed of block copolymers and any combination of the above polymers; and the polymer (A) is prepared by reacting a mixture including a tetracarboxylic dianhydride component (a) and a diamine component (b) Wherein the diamine component (b) comprises the diamine compound (b1) represented by the formula (Ib-1), formula (Ib-2) or formula (Ib-3):

Where Y is a single bond, -COO-, -CONR _d -or -NR _d -; R _d is a hydrogen atom, or a linear or branched alkyl group of C ₁ to C ₁₀ ; Ra is _a single bond or C ₁ to C linear or branched alkyl group of _10; R _b is a C ₁ to C ₁₀ straight chain or branched chain of oxyalkyl, nitrile group or carbonyl group; R _c is a C linear or branched alkyl of ₁ to ₁₀ C Group; or R _b and R _c may combine with each other to form a single ring; and a1 is an integer of 0 to 2. The method for manufacturing a liquid crystal alignment agent according to claim 5, wherein the total usage amount based on the diamine component (b) is 100 moles, and the formula (Ib-1), formula (Ib-2) or formula ( The amount of the diamine compound (b1) shown in Ib-3) is 3 to 40 moles. The method for manufacturing a liquid crystal alignment agent according to claim 5, wherein the use amount (A) based on the polymer is 100 parts by weight, and the use amount of the solvent (B) is 800 to 2500 parts by weight. The method for manufacturing a liquid crystal alignment agent according to claim 5, wherein the imidate ratio of the polymer (A) is 35% to 85%. A method for manufacturing a liquid crystal alignment film includes forming the liquid crystal alignment film from a liquid crystal alignment agent, wherein the liquid crystal alignment agent is formed by the method for manufacturing a liquid crystal alignment agent according to any one of claims 5 to 8. A method for manufacturing a liquid crystal display element comprising a liquid crystal alignment film, the method comprising forming the liquid crystal alignment film from a liquid crystal alignment agent, wherein the liquid crystal alignment agent is formed according to any one of claims 5 to 8 The liquid crystal alignment agent manufacturing method is formed.

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