Liquid crystal alignment agent for photo-alignment method, liquid crystal alignment film and liquid crystal display element

Abstract

The invention provides a liquid crystal alignment agent for a light alignment method, a liquid crystal alignment film formed by using the liquid crystal alignment agent, and a liquid crystal display component comprising the liquid crystal alignment film, wherein the liquid crystal alignment agent can reduce the brightness change rate after driving. The liquid crystal alignment agent comprises a polymer (A) with a specific structure and a solvent (C).

Description

Technical Field

[0001] The present invention relates to a liquid crystal alignment agent for optical alignment method, and in particular to a liquid crystal alignment agent for optical alignment method which can reduce the brightness change rate after driving, a liquid crystal alignment film formed using the liquid crystal alignment agent, and a liquid crystal display component comprising the liquid crystal alignment film. Background Art

[0002] Known liquid crystal display units are widely used as display components of personal computers, smart phones, mobile phones or television sets. The liquid crystal display unit may include a liquid crystal layer sandwiched between a component substrate and a color filter substrate, a pixel electrode and a common electrode for applying an electric field to the liquid crystal layer, an alignment film for controlling the alignment of liquid crystal molecules in the liquid crystal layer, and a thin film transistor (TFT) for switching the electronic signal supplied to the pixel electrode. As for the driving method of the liquid crystal molecules, there are known longitudinal electric field methods such as the TN (Twisted Nematic) method and the VA (Vertical Alignment) method, and transverse electric field methods such as the IPS (In-Plane Switching) method and the FFS (Fringe Field Switching) method.

[0003] At present, the most popular liquid crystal alignment film in the industry is obtained by rubbing the surface of a film composed of polyamic acid and / or polyimide obtained by imidization formed on an electrode substrate with a cloth such as cotton, nylon or polyester in one direction. The friction treatment is a simple and highly productive industrial method. However, with the high performance, high precision and large-scale liquid crystal display components, the surface of the alignment film is scarred by dust, mechanical force and static electricity generated by the friction treatment, which leads to various problems such as unevenness within the alignment treatment surface. As an alignment treatment method that replaces the friction treatment, a photoalignment method is known that imparts liquid crystal alignment ability by irradiating polarized radiation. With respect to the photoalignment method, Japanese Patent Publication No. 9-297313 has disclosed those that utilize photoisomerization reactions, those that utilize photocrosslinking reactions or those that utilize photodecomposition reactions.

[0004] However, the liquid crystal display device containing the conventional liquid crystal alignment film made by the photo-alignment method still has a poor brightness change rate after driving and cannot meet the application requirements. Summary of the invention

[0005] In view of this, one aspect of the present invention is to provide a liquid crystal alignment agent for photo-alignment method, which comprises a polymer (A) and a solvent (C). The liquid crystal alignment film formed by the liquid crystal alignment agent can reduce the brightness change rate of the liquid crystal display element after driving.

[0006] Another aspect of the present invention is to provide a liquid crystal alignment film, which is formed by using the liquid crystal alignment agent used in the above-mentioned photo-alignment method.

[0007] Another aspect of the present invention is to provide a liquid crystal display component, which includes the aforementioned liquid crystal alignment film and has a low brightness change rate after driving.

[0008] According to the above aspect of the present invention, a liquid crystal alignment agent for photo-alignment method is provided, and the liquid crystal alignment agent comprises a polymer (A) and a solvent (C). In addition to the polymer (A), the liquid crystal alignment agent for photo-alignment method of the present invention may also selectively comprise a polymer (B). This is described below.

[0009] Polymer (A)

[0010] The polymer (A) of the present invention may be selected from at least one polymer selected from the group consisting of a polyimide precursor obtained by reacting a tetracarboxylic dianhydride component (a1) and a diamine component (a2), and an imidized polymer of a polyimide precursor. For example, the polymer (A) may include a polyimide precursor having an imide precursor structure such as polyamic acid and polyamic acid ester, and / or an imidized product of the polyimide precursor (i.e., polyimide).

[0011] The polyimide precursor of the polymer (A) may include structures shown in the following formula (I) and formula (II).

[0012]

[0013] In formula (I), X1 represents a structure as shown in formula (I-1) below; X2 represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms; A1 and A2 represent a divalent aromatic ring group, and the ring portion may have a substituent, wherein A1 and A2 are the same; Y 11 represent R1 represents a group that is released by heat; Y 12 represents a single bond, an oxygen atom or a sulfur atom; Z1 represents a divalent organic group having at least one of a chain hydrocarbon structure and an alicyclic hydrocarbon structure and having a carbon number of 1 to 15, wherein when Y 12 When Z1 represents a sulfur atom, the carbon number of the divalent organic group represented by Z1 is not less than 2.

[0014]

[0015] In formula (I-1), X 11 , X 12 , X 13 With X 14Each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, a monovalent organic group having 1 to 6 carbon atoms and containing a fluorine atom, or a phenyl group, 11 To X 14 are the same or different, and X 11 , X 12 , X 13 With X 14 At least one of is not a hydrogen atom.

[0016] In some embodiments, X1 represents a structure as shown in formula (I-1-1).

[0017]

[0018] In some embodiments, A1 and A2 in formula (I) may represent a divalent group formed by removing two hydrogen atoms from a ring portion of a benzene ring, a pyridine ring, or a pyrimidine ring, wherein the ring portion may have a substituent, and A1 and A2 are the same; and Z1 represents And n represents an integer from 1 to 5.

[0019] In formula (II), X1 and X2 are as defined above; Y 21 Represents a single bond, -0-, -S-, -SS-, -SO2-, -CO-, -C(CH3)2-, -C(CF3)2-, -(CH2) m -、-O-(CH2) m -O- or -S-(CH2) m -S-, wherein m represents an integer from 1 to 12; Y 22 It represents a single bond, -O-, -S-, -CO-, -C(CH3)2-, -C(CF3)2- or an alkylene group having 1 to 10 carbon atoms.

[0020] In some embodiments, Y in formula (II) 21 With Y 22 They may each independently represent -O- or -S-.

[0021] If the polymer (A) does not contain the structures shown in formula (I) and formula (II), the brightness change rate of the liquid crystal display device formed by the liquid crystal alignment film containing the liquid crystal alignment agent after driving is not good.

[0022] Tetracarboxylic dianhydride component (a1)

[0023] In the present invention, the tetracarboxylic dianhydride component (a1) that reacts with the diamine component (a2) may be a tetracarboxylic dianhydride compound, or a tetracarboxylic dianhydride derivative such as a tetracarboxylic acid dihalide, a tetracarboxylic acid dialkyl ester, or a tetracarboxylic dianhydride dialkyl ester dihalide. The tetracarboxylic dianhydride component (a1) may be a single tetracarboxylic dianhydride compound or a derivative thereof, or may be a mixture of a plurality of them.

[0024] The tetracarboxylic dianhydride component (a1) may include an alicyclic tetracarboxylic dianhydride (a1-1) represented by the formula (A11) and other tetracarboxylic dianhydrides (a1-2).

[0025] Alicyclic tetracarboxylic dianhydride (a1-1) represented by formula (A11)

[0026] The tetracarboxylic dianhydride component (a1) used for the reaction to obtain the polymer (A) may include an alicyclic tetracarboxylic dianhydride (a1-1) or a derivative thereof as shown in the following formula (A11). The alicyclic tetracarboxylic dianhydride (a1-1) or a derivative thereof as shown in the formula (A11) may be composed of a single tetracarboxylic dianhydride or a derivative thereof, or may be composed of a plurality of tetracarboxylic dianhydrides or a derivative thereof.

[0027]

[0028] In formula (A11), X 11 , X 12 , X 13 With X 14 The definitions of are as mentioned above.

[0029] When X in formula (A11) 11 , X 12 , X 13 With X 14 When there is a steric barrier structure, it will lead to poor liquid crystal alignment of the liquid crystal alignment agent. 11 , X 12 , X 13 With X 14 Preferably it is a hydrogen atom, a methyl group or an ethyl group, and more preferably it is a methyl group.

[0030] In some specific examples, the alicyclic tetracarboxylic dianhydride (a1-1) represented by formula (A11) may include but is not limited to the compounds represented by the following formulas (A11-1) to (A11-8). Based on the brightness change rate after driving of the liquid crystal display device of the liquid crystal alignment film formed by the liquid crystal alignment agent, the alicyclic tetracarboxylic dianhydride (a1-1) represented by formula (A11) is preferably a compound represented by formula (A11-1).

[0031]

[0032]

[0033] Based on the total usage of the tetracarboxylic dianhydride component (a1) being 100 mol, the usage of the alicyclic tetracarboxylic dianhydride (a1-1) represented by formula (A11) may be 30 mol to 100 mol, preferably 40 mol to 100 mol, and more preferably 50 mol to 100 mol.

[0034] If the tetracarboxylic dianhydride component (a1) does not contain alicyclic tetracarboxylic dianhydride (a1-1) as shown in formula (A11), the liquid crystal alignment film formed by the liquid crystal alignment agent has a poor brightness change rate after driving.

[0035] Other tetracarboxylic dianhydrides (a1-2)

[0036] Other tetracarboxylic dianhydrides (a1-2) may include a tetracarboxylic dianhydride compound represented by the following formula (A12) and a derivative thereof.

[0037]

[0038] In formula (A12), X1′ may represent a structure as shown in the following formula (A12-1) to formula (A12-32), wherein “*” represents a bonding position.

[0039]

[0040]

[0041]

[0042] In formula (A12-5) and formula (A12-6), X 11 ′ and X 12 ' independently represent a single bond, -O-, -CO-, -COO-, phenylene, sulfonyl or amide, and multiple X 12 ' may be the same or different. a1 in formula (A12-5) represents an integer of 0 or 1; a1 in formula (A12-6) represents an integer of 0 or 1. In formula (A12-14), X 13 ' independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, a monovalent organic group having 1 to 6 carbon atoms and containing a fluorine atom, or a phenyl group, and multiple X 13 ' may be the same or different from each other. Based on the viewpoint of liquid crystal alignment, X 13 ' preferably represents a hydrogen atom, a halogen atom, a methyl group or an ethyl group, and more preferably represents a hydrogen atom or a methyl group.

[0043] In some specific examples, the aforementioned formula (A12-5) and formula (A12-6) may include but are not limited to the structures shown below.

[0044]

[0045]

[0046]

[0047] The above-mentioned other tetracarboxylic dianhydrides (a1-2) may be used alone or in combination of plural types.

[0048] Based on the total usage of the tetracarboxylic dianhydride component (a1) being 100 mol, the usage of the other tetracarboxylic dianhydride (a1-2) is 0 mol to 70 mol, preferably 0 mol to 60 mol, and more preferably 0 mol to 50 mol.

[0049] Diamine component (a2)

[0050] The diamine component (a2) may include a diamine compound (a2-1) as shown in formula (A21) and a diamine compound (a2-2) as shown in formula (A22). In addition, the diamine component (a2) may selectively include the following diamine compound (a2-3), other diamine compounds (a2-4), or any combination of the above compounds. The diamine component (a2) may be used alone or in combination of multiple types.

[0051] Diamine compound (a2-1)

[0052] The diamine compound (a2-1) may have a structure represented by the following formula (A21).

[0053] H2N-A1-Y 11 -Z1-Y 12 -A2-NH2 (A21)

[0054] In formula (A21), A1 and A2 represent a divalent aromatic ring group, and the ring portion may have a substituent, wherein A1 and A2 are the same; Y 11 represent R1 represents a group that is released by heat; Y 12 represents a single bond, an oxygen atom or a sulfur atom; Z1 represents a divalent organic group having at least one of a chain hydrocarbon structure and an alicyclic hydrocarbon structure and having a carbon number of 1 to 15, wherein when Y 12 When Z1 represents a sulfur atom, the carbon number of the divalent organic group represented by Z1 is not less than 2.

[0055] In formula (A21), A1 and A2 are groups formed by removing two hydrogen atoms from the ring part of an aromatic ring, and may have a substituent on the ring part. Examples of the aromatic ring include aromatic hydrocarbon rings such as a benzene ring, a naphthalene ring, an anthracene ring, and a biphenyl ring; and nitrogen-containing heterocyclic rings such as a pyridine ring, a pyrimidine ring, a pyrazine ring, and a pyridazine ring. The substituent on the aromatic ring may be, for example, an alkyl group having 1 to 6 carbon atoms. When A1 and A2 are the same, it is helpful to facilitate synthesis to prepare the polymer (A).

[0056] Preferably, A1 and A2 may be groups formed by removing two hydrogen atoms from the ring part of a benzene ring, a biphenyl ring, a pyridine ring or a pyrimidine ring, so as to obtain a liquid crystal alignment agent that can reduce the brightness change rate of the liquid crystal display element after driving.

[0057] In formula (A21), Y 11 represent R1 represents a group that is released by heat; Y 12 represents a single bond, an oxygen atom or a sulfur atom. The protecting group represented by R1 is preferably a carbamate protecting group, an amide protecting group, an imide protecting group or a sulfonamide protecting group. The protecting group represented by R1 may have a structure as shown in the following formula (A21′-1), and the aforementioned protecting group is a high thermal leaving group, so it can effectively reduce the residual amount of the deprotected part in the liquid crystal alignment film.

[0058]

[0059] In formula (A21′-1), Y 1 represents a single bond or a divalent hydrocarbon group having 1 to 4 carbon atoms.

[0060] In formula (A21), Z1 represents a divalent organic group having a chain hydrocarbon structure with a carbon number of 1 to 15 or an alicyclic hydrocarbon structure with a carbon number of 3 to 15. The "chain hydrocarbon structure" refers to a straight-chain hydrocarbon structure and a branched hydrocarbon structure that do not contain a cyclic structure but only contain a chain structure. The chain hydrocarbon structure may be saturated or unsaturated. The "alicyclic hydrocarbon structure" refers to a hydrocarbon structure that only contains an alicyclic hydrocarbon structure as a ring structure and does not contain an aromatic ring structure. The alicyclic hydrocarbon structure is not limited to a structure that only contains alicyclic hydrocarbons, and a part of it may also contain a chain structure.

[0061] Preferably, in formula (A21), when A1 and A2 represent a divalent group formed by removing two hydrogen atoms from a ring portion of a benzene ring, a pyridine ring or a pyrimidine ring, wherein the ring portion may have a substituent, and A1 and A2 are the same; and Z1 represents When n represents an integer from 1 to 5, the liquid crystal alignment film prepared by using the liquid crystal alignment agent can further reduce the brightness change rate of the liquid crystal display component after driving.

[0062] From the viewpoint of reducing the brightness change rate after driving, the bonding position on the benzene ring, pyridine ring or pyrimidine ring represented by A1 and A2 in formula (A21) is preferably para relative to the nitrogen atom in formula (A21). The diamine compound (a2-1) represented by the above formula (A21) is preferably a diamine compound represented by the following formula (A21′-2).

[0063]

[0064] In formula (A21′-2), Q1 and Q2 each independently represent —CH— or a nitrogen atom; Y 11 With Y 12 The definition of is as mentioned above; m 1 Represents an integer from 1 to 5.

[0065] In some specific examples, the diamine compound (a2-1) of the present invention may include but is not limited to the compounds shown in the following formulas (A21-1) to (A21-11). The specific compounds of the diamine compound (a2-1) can be synthesized by a general method of suitable combinatorial organic chemistry. The diamine compound (a2-1) can be used alone or in combination of multiple types. In the following formulas (A21-1) to (A21-11), R b It represents t-butyloxy carbonyl.

[0066]

[0067]

[0068] Based on 100 mol of the diamine component (a2), the total usage of the diamine compound (a2-1) represented by formula (A21) is 1 mol to 20 mol, preferably 2 mol to 15 mol, and more preferably 3 mol to 10 mol.

[0069] If the diamine component (a2) of the polymer (A) does not contain the diamine compound (a2-1) represented by formula (A21), the brightness change rate of the liquid crystal display device after driving of the liquid crystal alignment film formed by the liquid crystal alignment agent is poor.

[0070] Diamine compound (a2-2)

[0071] The diamine compound (a2-2) may have a structure represented by the following formula (A22).

[0072]

[0073] In formula (A22), Y 21 Represents a single bond, -O-, -S-, -SS-, -SO2-, -CO-, -C(CH3)2-, -C(CF3)2-, -(CH2) m -、-O-(CH2) m -O- or -S-(CH2) m -S-, and m represents an integer from 1 to 12; and Y 22 It represents a single bond, -O-, -S-, -CO-, -C(CH3)2-, -C(CF3)2- or an alkylene group having 1 to 10 carbon atoms.

[0074] In formula (A22), the hydrogen atoms of the benzene ring may be substituted or unsubstituted by -F, -CH3, -OH, -CF3 or benzyl. The group whose bonding position is not fixed to any carbon atom constituting the benzene ring means that its bonding position to the benzene ring is arbitrary. The bonding position of -NH2 to the benzene ring is 1 to 2, except for Y. 21 or Y 22 Preferably, Y 21 With Y 22 Each independently represents -O- or -S-. 21 With Y 22 When they independently represent -O- or -S-, the liquid crystal alignment film prepared by using the liquid crystal alignment agent can further reduce the brightness change rate of the liquid crystal display component after driving.

[0075] In some specific examples, the diamine compound (a2-2) represented by formula (A22) may include but is not limited to the compounds represented by the following formulae (A22-1) to (A22-7).

[0076]

[0077]

[0078] The above-mentioned diamine compounds (a2-2) may be used alone or in combination of plural types.

[0079] Based on 100 mol of the total usage of the diamine component (a2), the usage of the diamine compound (a2-2) may be 10 mol to 60 mol, preferably 12 mol to 50 mol, and more preferably 15 mol to 40 mol.

[0080] If the diamine component (a2) does not include the diamine compound (a2-2) represented by formula (A22), the brightness change rate of the liquid crystal display device formed by the liquid crystal alignment film containing the liquid crystal alignment agent after driving is not good.

[0081] Diamine compound (a2-3)

[0082] The diamine compound (a2-3) may include a diamine compound represented by the following formula (A23-1) or formula (A23-2).

[0083]

[0084] In formula (A23-1), Y 31 represents a divalent organic group as shown in the following formula (A23-3). 32 Each independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. 33 Each independently represents a divalent organic group represented by the following formula (A23-3′).

[0085]

[0086] In formula (A23-3), Ar each independently represents a divalent benzene ring, a biphenyl structure or a naphthalene ring, and the hydrogen atoms of the benzene ring, the biphenyl structure or the naphthalene ring may be substituted by a monovalent substituent or may not be substituted; Y 31 ' represents -(CH2) n -, n represents an integer from 2 to 18, and -(CH2) n At least one -CH2- in - may be substituted by -O-, -C(=O)- or -OC(=O)- or may be unsubstituted; p1 represents an integer of 0 or 1; "*" represents a bonding position.

[0087] In formula (A23-3′), Ar′ independently represents a divalent benzene ring or a biphenyl structure, and the hydrogen atoms of the benzene ring or the biphenyl structure may be substituted by a monovalent substituent or may not be substituted; Y 33 ' represents -(CH2) n -, n represents an integer from 2 to 18, and -(CH2) n At least one -CH2- in - may be substituted by -O-, -C(=O)- or -OC(=O)- or may be unsubstituted; p2 represents an integer of 0 or 1; "*" represents a bonding position.

[0088] The monovalent substituent group of the aforementioned benzene ring, biphenyl structure, or naphthalene ring may be, for example, a halogen atom, an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, a fluoroalkyl group having 1 to 10 carbon atoms, a fluoroalkenyl group having 2 to 10 carbon atoms, a fluoroalkoxy group having 1 to 10 carbon atoms, a carboxyl group, a hydroxyl group, an alkoxycarbonyl group having 1 to 10 carbon atoms, a cyano group, a nitro group, or the like.

[0089] From the perspective of improving the liquid crystal alignment, the divalent organic group represented by formula (A23-3) may preferably include groups represented by the following formulae (A23-3-1) to (A23-3-16), wherein "*" represents the bonding position.

[0090]

[0091]

[0092] In formula (A23-3-14), each of m independently represents an integer of 1 to 3.

[0093] From the viewpoint of improving the liquid crystal alignment, the divalent organic group represented by formula (A23-3′) may preferably include groups represented by formulae (A23-3-7) to (A23-3-16).

[0094] When the diamine compound (a2-3) comprises a plurality of diamine compounds as shown in formula (A23-1), it is preferably Y in formula (A23-1): 31 The diamine compounds represented by formula (A23-3-1) to formula (A23-3-14) and Y in formula (A23-1) 31 It represents a combination of diamine compounds of formula (A23-3-15) to formula (A23-3-16).

[0095] In some specific examples, the diamine compound represented by the aforementioned formula (A23-2) may include but is not limited to the diamine compounds represented by the following formulas (A23-2-1) to (A23-2-5).

[0096]

[0097]

[0098] The aforementioned diamine compounds (a2-3) may be used alone or in combination of two or more.

[0099] Based on 100 mol of the total usage of the diamine component (a2), the usage of the diamine compound (a2-3) may be 20 mol to 89 mol, preferably 38 mol to 90 mol, and more preferably 50 mol to 87 mol.

[0100] Other diamine compounds (a2-4)

[0101] In addition to the aforementioned diamine compound (a2-1) represented by formula (A21), the diamine compound (a2-2) represented by formula (A22), and the diamine compound (a2-3), the diamine component (a2) used to obtain the polymer (A) may selectively include other diamine compounds (a2-4). For example, other diamine compounds (a2-4) may include but are not limited to: 4,4′-diaminoazobenzene or diamine compounds represented by the following formulas (A24-1) to (A24-3) and the like having a photo-alignment group; 2,4-diaminophenol, 3,5-diaminophenol, 3,5-diaminobenzyl alcohol, 2,4-diaminobenzyl alcohol or 4,6-diaminoresorcinol; 2,4-diaminobenzoic acid, 2,5-diaminobenzoic acid, 3,5-diaminobenzoic acid or diamine compounds represented by the following formulas (A24-4) to (A24-7) and the like having a carboxyl group; 3,3′-diaminodiphenylmethane, 4,4′-diaminodiphenylmethane, 3,4′-diaminodiphenylmethane, 4,4′-diaminodiphenyl ketone , 1,4-bis(4-aminobenzyl)benzene, 4,4′-diaminodiphenyl ether, 1-(4-aminophenyl)-1,3,3-trimethyl-1H-dihydroindene-5-amine or 1-(4-aminophenyl)-2,3-dihydro-1,3,3-trimethyl-1H-indene-6-amine; diamine compounds having a urea bond such as diamine compounds represented by the following formulas (A24-8) to (A24-10); diamine compounds having an amide bond such as diamine compounds represented by the following formulas (A24-11) to (A24-13); diamine compounds having a photopolymerizable group at the end such as methacrylate 2-(2,4-diaminophenoxy)ethyl or 2,4-diamino-N,N-diallylaniline; diamine compounds having a photopolymerizable group at the end such as diamine compounds represented by the following formulas (A24-14) to (A24-15); A diamine compound with an oxazoline structure.

[0102]

[0103]

[0104]

[0105] In formula (A24-4), Y 41represents a single bond, -CH2-, -C2H4-, -C(CH3)2-, -CF2-, -C(CF3)2-, -O-, -CO-, -NH-, -N(CH3)-, -CONH-, -NHCO-, -CH2O-, -OCH2-, -COO-, -OCO-, -CON(CH3)- or -N(CH3)CO-; m1 and m2 each independently represent an integer from 0 to 4, and (m1+m2) represents an integer from 1 to 4. In formula (A24-5), m3 and m4 each independently represent an integer from 1 to 5. In formula (A24-6), Y 42 represents a linear or branched alkyl group having 1 to 5 carbon atoms; m5 represents an integer from 1 to 5. In formula (A24-7), Y 43 and Y 44 Each independently represents a single bond, -CH2-, -C2H4-, -C(CH3)2-, -CF2-, -C(CF3)2-, -O-, -CO-, -NH-, -N(CH3)-, -CONH-, -NHCO-, -CH2O-, -OCH2-, -COO-, -OCO-, -CON(CH3)- or -N(CH3)CO-; m6 represents an integer from 1 to 4.

[0106] The above-mentioned other diamine compounds (a2-4) may be used alone or in combination of plural types.

[0107] Based on the total usage of the diamine component (a2) being 100 mol, the usage of the other diamine compounds (a2-4) may be 0 mol to 80 mol, preferably 0 mol to 60 mol, and more preferably 0 mol to 40 mol.

[0108] Polymer (B)

[0109] In addition to the aforementioned polymer (A), the liquid crystal alignment agent of the present invention may also selectively contain a polymer (B) selected from the group consisting of a polyimide precursor obtained by using a tetracarboxylic dianhydride component (b1) and a diamine component (b2), and an imidized polymer (i.e., polyimide) of the polyimide precursor. For example, the polymer (B) may include, but is not limited to, at least one polymer selected from the group consisting of a polyimide precursor obtained by using a tetracarboxylic dianhydride component (b1) and a diamine component (b2) that does not contain the aforementioned specific diamine compound (e.g., diamine compound (a2-1) and diamine compound (a2-2)) and an imidized product (i.e., polyimide) of the polyimide precursor, i.e., the polyimide precursor of the polymer (B) does not contain the structures shown in the above formula (I) and formula (II). Specific examples of the above polyimide precursor may include, for example, polyamic acid or polyamic acid ester. The polymer (B) may be used alone or in combination of two or more.

[0110] The usage ratio of polymer (A) to polymer (B) (ie, the mass ratio of [polymer (A)] / [polymer (B)]) may be 10 / 90 to 90 / 10, preferably 20 / 80 to 90 / 10, and more preferably 20 / 80 to 80 / 20.

[0111] Tetracarboxylic dianhydride component (b1)

[0112] The tetracarboxylic dianhydride component (b1) used to obtain the polymer (B) may include, for example, but not limited to, non-cyclic aliphatic tetracarboxylic dianhydride compounds, alicyclic tetracarboxylic dianhydride compounds, aromatic tetracarboxylic dianhydride compounds, or derivatives of these compounds. Specific examples of non-cyclic aliphatic tetracarboxylic dianhydride compounds, alicyclic tetracarboxylic dianhydride compounds, and aromatic tetracarboxylic dianhydride compounds may include, for example, the tetracarboxylic dianhydride compounds exemplified for the aforementioned polymer (A). Preferably, the tetracarboxylic dianhydride component (b1) may include alicyclic tetracarboxylic dianhydride or its derivatives as shown in the above formula (A11), or tetracarboxylic dianhydride compounds or their derivatives as shown in the above formula (A12) and X1′ represents a structure shown in formula (A12-1) to formula (A12-6). The tetracarboxylic dianhydride component (b1) may be used alone or in combination of a plurality of types.

[0113] Based on the viewpoint of further reducing the brightness change rate after driving, the tetracarboxylic dianhydride component (b1) preferably comprises a tetracarboxylic dianhydride compound (hereinafter referred to as tetracarboxylic dianhydride compound (b1-1)) as shown in the above formula (A12) and X1′ represents a structure shown in the following formula (III).

[0114]

[0115] In formula (III), Z 11 represents a single bond; and “*” represents a bonding position.

[0116] The aforementioned tetracarboxylic dianhydride compound (b1-1) may be used alone or in combination of two or more.

[0117] More preferably, the tetracarboxylic dianhydride component (b1) comprises a tetracarboxylic dianhydride compound represented by the following formula (IV).

[0118]

[0119] Based on 100 mol of the total usage of the tetracarboxylic dianhydride component (b1), the usage of the tetracarboxylic dianhydride compound (b1-1) may be 30 mol to 100 mol, preferably 40 mol to 100 mol, and more preferably 50 mol to 100 mol.

[0120] If the tetracarboxylic dianhydride component (b1) includes the tetracarboxylic dianhydride compound (b1-1), the liquid crystal display device containing the liquid crystal alignment film formed by the liquid crystal alignment agent can have a better brightness change rate after driving.

[0121] Diamine component (b2)

[0122] The diamine component (b2) used to obtain the polymer (B) may, for example, include but is not limited to the aforementioned diamine component (a2), or a diamine compound having at least one nitrogen atom structure selected from the group consisting of a nitrogen-containing heterocyclic ring, a secondary amine group and a tertiary amine group (hereinafter referred to as diamine compound (b2-1)), but the diamine component (b2) does not include the aforementioned diamine compound (a2-1) and diamine compound (a2-2).

[0123] The diamine component (b2) can be used alone or in combination of two or more.

[0124] Diamine compound (b2-1)

[0125] The diamine compound (b2-1) having the above-mentioned specific nitrogen-containing atom structure may have a nitrogen-containing heterocyclic ring, for example, pyrrole, imidazole, pyrazole, triazole, pyridine, pyrimidine, tantalum, Pyridine Indole, benzimidazole, purine, quinoline, isoquinoline, Pyridine, quinone Phylin three Carbazole, acridine, piperidine, piperidine Pyrrolidine or hexamethyleneimine, etc. Among them, pyridine, pyrimidine, pyrrolidine Piperidine, piperidine Quinoline, carbazole or acridine is preferred.

[0126] The diamine compound (b2-1) having the above-mentioned specific nitrogen atom-containing structure may include a secondary amine group and a tertiary amine group as represented by the following formula (B21).

[0127]

[0128] In formula (B21), Z represents a hydrogen atom or an alkyl group, a cycloalkyl group or an aryl group having 1 to 10 carbon atoms; "*" represents the bonding position of the hydrocarbon group.

[0129] The alkyl represented by Z may include, but not limited to, methyl, ethyl or propyl; the cycloalkyl represented by Z may include, but not limited to, cyclohexyl; the aryl represented by Z may include, but not limited to, phenyl or tolyl. Z is preferably a hydrogen atom or a methyl group.

[0130] Specific examples of the diamine compound (b2-1) having the above-mentioned specific nitrogen-containing atom structure include: 2,6-diaminopyridine, 3,4-diaminopyridine, 2,4-diaminopyrimidine, 3,6-diaminocarbazole, N-methyl-3,6-diaminocarbazole, 1,4-bis-(4-aminophenyl)-piperidin 3,6-diaminoacridine, N-ethyl-3,6-diaminocarbazole, N-phenyl-3,6-diaminocarbazole, diamine compounds represented by the following formulas (B21-1) to (B21-8), or diamine compounds represented by the following formulas (B21-9) to (B21-26).

[0131]

[0132]

[0133]

[0134]

[0135] The diamine compound (b2-1) may be used alone or in combination of two or more.

[0136] Based on 100 mol of the total usage of the diamine component (b2), the usage of the diamine compound (b2-1) may be 15 mol to 100 mol, preferably 20 mol to 90 mol, and more preferably 25 mol to 80 mol.

[0137] If the diamine component (b2) includes the diamine compound (b2-1), the liquid crystal alignment film prepared by using the liquid crystal alignment agent can further reduce the brightness change rate of the liquid crystal display element after driving.

[0138] Method for making polymer

[0139] The manufacture of polymer (A) or polymer (B) can be carried out by making the aforementioned diamine component and tetracarboxylic dianhydride component carry out (condensation polymerization) reaction in a solvent. When a part of polymer (A) or polymer (B) has an amic acid structure, for example, by reacting the tetracarboxylic dianhydride component with the diamine component, a polymer (i.e., polyamic acid) having an amic acid structure is obtained. The aforementioned solvent is not particularly limited, and it only needs to be able to dissolve the formed polymer. For example, the specific example of the solvent may include but is not limited to N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, γ-butyrolactone, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide or 1,3-dimethyl-2-imidazolidinone. In some specific examples, when the solvent solubility of the polymer is high, the solvent may include methyl ethyl ketone, cyclohexanone, cyclopentanone, 4-hydroxy-4-methyl-2-pentanone, or a solvent as shown in the following formula (D-1) to formula (D-3). In formula (D-1), Z1 represents an alkyl group having 1 to 3 carbon atoms. In formula (D-2), Z2 represents an alkyl group having 1 to 3 carbon atoms. In formula (D-3), Z3 represents an alkyl group having 1 to 4 carbon atoms.

[0140]

[0141] The aforementioned solvents can be used alone or in combination. Secondly, even if the solvent is insoluble in the polymer, it can still be mixed with the above-mentioned solvents within the range that the generated polymer will not precipitate. When the diamine component and the tetracarboxylic dianhydride component react in a solvent, the reaction can be carried out at any concentration, but preferably 1wt% to 50wt%, and more preferably 5wt% to 30wt%. The reaction can also be carried out at a high concentration initially, and then additional solvent is added. When the reaction is carried out, the ratio of the total molar number of the diamine component to the total molar number of the tetracarboxylic dianhydride component is preferably 0.8 to 1.2. Similar to the general polycondensation reaction, the closer this molar ratio is to 1.0, the greater the molecular weight of the polymer (A) or polymer (B) formed.

[0142] The polymer having an amide ester structure can be obtained, for example, by the following known methods: (1) a method in which the polyamide acid obtained by the above method is further reacted with an esterifying agent, (2) a method in which a tetracarboxylic acid diester compound is reacted with a diamine compound, or (3) a method in which a tetracarboxylic acid diester dihalide is reacted with a diamine compound.

[0143] The imide compound in the polymer (A) or polymer (B) contained in the liquid crystal alignment agent of the present invention can be obtained, for example, by subjecting the polymer obtained above to a dead cycle. In the imide compound, the dead cycle rate (also referred to as the imidization rate) of the functional group possessed by the amic acid group or its derivative is not necessarily 100%, and the imidization rate can be arbitrarily adjusted according to the use and / or purpose.

[0144] The method for obtaining the imide product may be, for example, thermal imidization in which the polymer solution obtained by the above reaction is directly heated, or catalytic imidization in which a catalyst is added to the polymer solution. When thermal imidization is performed in the solution, the temperature is preferably 100° C. to 400° C., and more preferably 120° C. to 250° C. When thermal imidization is performed, it is preferred to discharge the water generated by the imidization reaction out of the system.

[0145] The aforementioned catalytic imidization can be carried out, for example, by adding an alkaline catalyst and anhydride to the polymer solution obtained by the reaction, preferably at -20°C to 250°C, and more preferably at 0°C to 180°C for stirring. The amount of alkaline catalyst added is preferably 0.5 to 30 moles of the amide acid group, and more preferably 2 to 20 moles; the amount of anhydride added is preferably 1 to 50 moles of the amide acid group, and more preferably 3 to 30 moles. Specific examples of alkaline catalysts may include but are not limited to pyridine, triethylamine, trimethylamine, tributylamine or trioctylamine. Among them, pyridine is more ideal because it has a moderate alkalinity that allows the reaction to proceed. Specific examples of anhydrides may include but are not limited to acetic anhydride, trimellitic anhydride or benzene tetracarboxylic anhydride. Among them, if acetic anhydride is used, purification after the reaction is easier, so it is more ideal. The imidization rate of catalytic imidization can be controlled by adjusting the amount of catalyst, reaction temperature and / or reaction time.

[0146] When the imide formed is recovered from the reaction solution of the above-mentioned imidization, the reaction solution is put into a solvent and precipitated. The solvent used for precipitation may include, but is not limited to, methanol, ethanol, isopropanol, acetone, hexane, butyl cellosolve, heptane, methyl ethyl ketone, methyl isobutyl ketone, toluene, benzene or water. After filtering and recovering the polymer precipitated by the solvent, it can be dried at normal pressure or reduced pressure, at room temperature or by heating. Alternatively, the polymer recovered by precipitation is dissolved in a solvent again, and reprecipitation is carried out for recovery, and this operation is repeated 2 to 10 times to reduce impurities in the polymer. The solvent used may be, for example, alcohols or ketone hydrocarbons. If used in the three or more solvents selected therein, the efficiency of refining can be further improved, so it is more ideal.

[0147] Solution viscosity and molecular weight of polymers

[0148] When the solution is prepared into a concentration of 10 wt% to 15 wt%, the solution concentration of the polymer (A) or polymer (B) of the present invention is not particularly limited. Based on the viewpoint of easier operation, the solution concentration can be, for example, 10 mPa·s to 1000 mPa·s. The solution viscosity (mPa·s) of the polymer is a value measured at 25°C using a good solvent for the polymer (e.g., γ-butyrolactone or N-methyl-2-pyrrolidone, etc.) to prepare a polymer solution with a concentration of 10 wt% to 15 wt%.

[0149] The weight average molecular weight (M) of the polymer (A) or (B) of the present invention measured by gel permeation chromatography (GPC) in terms of polystyrene is w ) is preferably 1,000 to 500,000, and more preferably 2,000 to 500,000. w The number average molecular weight (M) of the polystyrene was measured by GPC. n ) ratio represents the molecular weight distribution (M w / M n ) is preferably less than 15, and more preferably less than 10. When the molecular weight of the polymer is within the aforementioned molecular weight range, it can ensure good orientation and stability of the liquid crystal display device.

[0150] Capping agent

[0151] When synthesizing the polymer (A) or polymer (B) of the present invention, the tetracarboxylic dianhydride component and the diamine component as described above can be used, and an appropriate end-capping agent can be used to synthesize an end-sealed polymer. The end-sealed polymer has the effect of improving the film hardness of the liquid crystal alignment film obtained by using the coating, and improving the sealing properties of the sealant and the liquid crystal alignment film. The end of the polymer (A) or polymer (B) of the present invention may, for example, contain an amine group, a carboxyl group, an anhydride group or a derivative thereof. The amine group, carboxyl group, anhydride group or a derivative thereof can be obtained by a general condensation reaction, or by using an end-capping agent described later to seal the end. Similarly, the aforementioned derivatives can be obtained, for example, using the following end-capping agent.

[0152] For example, the end-capping agent may include, but is not limited to, acetic anhydride, maleic anhydride, neddic anhydride, phthalic anhydride, itaconic anhydride, cyclohexanedicarboxylic anhydride, 3-hydroxyphthalic anhydride, trimellitic anhydride, 3-((3-trimethoxysilyl)propyl)-3,4-dihydrofuran-2,5-dione, 4,5,6,7-tetrafluoroisobenzofuran-1,3-dione or 4-ethynylphthalic anhydride; dibutyl dicarbonate or diallyl dicarbonate; Carbonic acid diester compounds; chlorocarbonyl compounds such as acryloyl chloride, methacryloyl chloride or nicotinyl chloride; monoamine compounds such as aniline, 2-aminophenol, 3-aminophenol, 4-aminosalicylic acid, 5-aminosalicylic acid, 6-aminosalicylic acid, 2-aminobenzoic acid, 3-aminobenzoic acid, 4-aminobenzoic acid, cyclohexylamine, n-butylamine, n-pentylamine, n-hexylamine, n-heptylamine or n-octylamine; monoisocyanate compounds such as ethyl isocyanate, phenyl isocyanate or naphthyl isocyanate, etc.

[0153] The blocking agents may be used alone or in combination of two or more.

[0154] Based on 100 mol parts of the total usage of the diamine component, the usage of the end-capping agent is preferably 0.01 mol parts to 20 mol parts, and more preferably 0.01 mol parts to 10 mol parts.

[0155] Other ingredients in liquid crystal alignment agents

[0156] The liquid crystal alignment agent of the present invention may include a polymer (A) and a polymer (B) added as needed. In addition to the polymer (A) and the polymer (B), the liquid crystal alignment agent of the present invention may selectively include other polymers. The types of other polymers may include, for example, but are not limited to, polyesters, polyamides, polyureas, polyorganosiloxanes, cellulose derivatives, polyacetals, polystyrenes or their derivatives, poly(styrene-phenylmaleimide) derivatives, or poly(meth)acrylates.

[0157] Solvent (C)

[0158] Based on the viewpoint of forming a uniform thin film, the liquid crystal alignment agent takes the form of a coating liquid to produce a liquid crystal alignment film. The liquid crystal alignment agent of the present invention is preferably a coating liquid containing the above-mentioned polymer component and an organic solvent (hereinafter referred to as solvent (C)). Among them, based on the set thickness of the coating film to be formed, the polymer concentration in the liquid crystal alignment agent can be appropriately changed. Based on the viewpoint of forming a uniform and defect-free coating film, the polymer concentration in the liquid crystal alignment agent is preferably above 1wt%. Based on the viewpoint of the storage stability of the solution, the polymer concentration in the liquid crystal alignment agent is preferably below 10wt%. The ideal polymer concentration can be 2wt% to 8wt%. The content of polymer (A) in the liquid crystal alignment agent can be appropriately changed by the coating method of the liquid crystal alignment agent and / or the film thickness of the desired liquid crystal alignment film, and it can preferably be 2wt% to 10wt%, and more preferably 3wt% to 7wt%.

[0159] There is no particular limitation on the organic solvent contained in the liquid crystal alignment agent, and it only needs to be able to uniformly dissolve the aforementioned polymer. Specific examples thereof include, but are not limited to, N,N-dimethylformamide, N,N-dimethylacetamide, N,N-dimethyllactamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, dimethyl sulfoxide, γ-butyrolactone, γ-valerolactone, 1,3-dimethyl-2-imidazolidinone, methyl ethyl ketone, cyclohexanone, cyclopentanone, 3-methoxy-N,N-dimethylpropionamide, 3-butoxy-N,N-dimethylpropionamide, N-(n-propyl)-2-pyrrolidone, N-isopropyl-2-pyrrolidone, N-(n-butyl)-2-pyrrolidone, N-(tert-butyl)-2-pyrrolidone, N-(n-pentyl)-2-pyrrolidone, N-methoxypropyl-2-pyrrolidone, N-ethoxyethyl-2-pyrrolidone, N-methoxybutyl-2-pyrrolidone or N-cyclohexyl-2-pyrrolidone, etc., and the aforementioned organic solvents are also called good solvents. Among them, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 3-methoxy-N, N-dimethylpropionamide, 3-butoxy-N, N-dimethylpropionamide or γ-butyrolactone is preferred. Based on 100 wt % of the total amount of the solvent in the liquid crystal alignment agent, the amount of the good solvent may be 20 wt % to 99 wt %, preferably 20 wt % to 90 wt %, and more preferably 30 wt % to 80 wt %.

[0160] Secondly, the organic solvent in the liquid crystal alignment agent is preferably a mixed solvent of the aforementioned solvent and a solvent (also referred to as a poor solvent) that can improve the coating properties of the liquid crystal alignment agent and the surface smoothness of the coating film. The specific poor solvent used in combination can be, for example, but not limited to, the solvent described below. Based on the total amount of solvents used in the liquid crystal alignment agent being 100wt%, the amount of the poor solvent used is preferably 1wt% to 80wt%, more preferably 10wt% to 80wt%, and particularly preferably 20wt% to 70wt%. The type and amount of the poor solvent used can be appropriately selected based on the coating device, coating conditions and / or coating environment of the liquid crystal alignment agent.

[0161] For example, the poor solvent may be, for example, diisopropyl ether, diisobutyl ether, diisobutyl carbinol (2,6-dimethyl-4-heptanol), ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, 1,2-butoxyethane, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, 4-hydroxy-4-methyl-2-pentanone, diethylene glycol methyl ethyl ether, diethylene glycol dibutyl ether, 3-ethoxybutyl acetate, 1-methylpentyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, ethylene glycol monoacetate, ethylene glycol diacetate, propylene carbonate, ethylene carbonate, ethylene glycol monobutyl ether (butyl celoxylate), ethylene glycol monoisopentyl ether, ethylene glycol monohexyl ether, propylene glycol monobutyl ether, 1-(2-butoxyethoxy) )-2-propanol, 2-(2-butoxyethoxy)-1-propanol, propylene glycol monomethyl ether acetate, propylene glycol diacetate, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol dimethyl ether, ethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, 2-(2-ethoxyethoxy)ethyl acetate, diethylene glycol acetate, propylene glycol diacetate, n-butyl acetate, propylene glycol monoethyl ether acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, propyl 3-methoxypropionate, butyl 3-methoxypropionate, n-butyl lactate, isopentyl lactate, diethylene glycol monoethyl ether, or diisobutyl ketone (2,6-dimethyl-4-heptanone), etc.

[0162] Among them, diisobutyl carbinol, propylene glycol monobutyl ether, propylene glycol diacetate, diethylene glycol diethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol dimethyl ether, 4-hydroxy-4-methyl-2-pentanone, ethylene glycol monobutyl ether, ethylene glycol monobutyl ether acetate, or diisobutyl ketone is preferred.

[0163] The solvent combination of the good solvent and the poor solvent can be preferably, for example, but not limited to, N-methyl-2-pyrrolidone and ethylene glycol monobutyl ether; N-methyl-2-pyrrolidone, γ-butyrolactone and ethylene glycol monobutyl ether; N-methyl-2-pyrrolidone, γ-butyrolactone and propylene glycol monobutyl ether; N-ethyl-2-pyrrolidone and propylene glycol monobutyl ether; N-ethyl-2-pyrrolidone and 4-hydroxy-4-methyl-2-pentanone; N-ethyl-2-pyrrolidone and propylene glycol diacetate; N,N-dimethyl lactamide and diisobutyl ketone; N-methyl-2-pyrrolidone and ethyl 3-ethoxypropionate; N-ethyl-2-pyrrolidone and ethyl 3-ethoxypropionate; N-methyl-2-pyrrolidone and ethyl Glycol monobutyl ether acetate; N-ethyl-2-pyrrolidone and dipropylene glycol dimethyl ether; N,N-dimethyl lactamide and ethylene glycol monobutyl ether; N,N-dimethyl lactamide and propylene glycol diacetate; N-ethyl-2-pyrrolidone and diethylene glycol diethyl ether; N,N-dimethyl lactamide and diethylene glycol diethyl ether; N-methyl-2-pyrrolidone, γ-butyrolactone, 4-hydroxy-4-methyl-2-pentanone and diethylene glycol diethyl ether; N-ethyl-2-pyrrolidone, N-methyl-2-pyrrolidone and 4-hydroxy-4-methyl-2-pentanone; N-ethyl-2-pyrrolidone, 4-hydroxy-4-methyl-2-pentanone and propylene glycol monobutyl ether; N-methyl-2-pyrrolidone, 4-Hydroxy-4-methyl-2-pentanone and diisobutyl ketone; N-methyl-2-pyrrolidone, 4-hydroxy-4-methyl-2-pentanone and dipropylene glycol monomethyl ether; N-methyl-2-pyrrolidone, 4-hydroxy-4-methyl-2-pentanone and propylene glycol monobutyl ether; N-methyl-2-pyrrolidone, 4-hydroxy-4-methyl-2-pentanone and propylene glycol diacetate; γ-butyrolactone, 4-hydroxy-4-methyl-2-pentanone and diisobutyl ketone; γ-butyrolactone, 4-hydroxy-4-methyl-2-pentanone and propylene glycol diacetate; N-methyl-2-pyrrolidone, γ-butyrolactone, propylene glycol monobutyl ether and diisobutyl ketone; N-methyl-2-pyrrolidone, γ-butyrolactone and propylene glycol diacetate Glycol monobutyl ether and diisopropyl ether; N-methyl-2-pyrrolidone, γ-butyrolactone, propylene glycol monobutyl ether and diisobutyl carbinol; N-methyl-2-pyrrolidone, γ-butyrolactone and dipropylene glycol dimethyl ether; N-methyl-2-pyrrolidone, propylene glycol monobutyl ether and dipropylene glycol dimethyl ether; N-ethyl-2-pyrrolidone, propylene glycol monobutyl ether and dipropylene glycol monomethyl ether; N-ethyl-2-pyrrolidone, propylene glycol monobutyl ether and propylene glycol diacetate; N-ethyl-2-pyrrolidone, propylene glycol monobutyl ether and diisobutyl ketone; N-ethyl-2-pyrrolidone, γ-butyrolactone and diisobutyl ketone; or N-ethyl-2-pyrrolidone, N,N-dimethyl lactamide and diisobutyl ketone, etc.

[0164] The aforementioned solvent (C) may be used alone or in combination of two or more.

[0165] Based on 100 parts by weight of the total amount of polymer (A) and polymer (B), the amount of solvent (C) is 800 to 4000 parts by weight, preferably 900 to 3500 parts by weight, and more preferably 1000 to 3000 parts by weight.

[0166] additive

[0167] The liquid crystal alignment agent of the present invention may also selectively add components other than the polymer component and the organic solvent (hereinafter referred to as additive components). These additive components may include, for example, but are not limited to: a bonding aid for improving the adhesion between the liquid crystal alignment film and the substrate or the adhesion between the liquid crystal alignment film and the sealant, a compound for improving the strength of the liquid crystal alignment film (hereinafter referred to as a cross-linking compound), a compound for promoting imidization, a dielectric or conductive substance for adjusting the dielectric constant or resistance of the liquid crystal alignment film, etc.

[0168] Sealing agent

[0169] The aforementioned adhesion aid can be, for example, 3-aminopropyl trimethoxysilane, 3-aminopropyl triethoxysilane, 3-aminopropyl diethoxymethyl silane, 2-aminopropyl trimethoxysilane, 2-aminopropyl triethoxysilane, N-(2-aminoethyl)-3-aminopropyl trimethoxysilane, N-(2-aminoethyl)-3-aminopropyl methyl dimethoxysilane, 3-ureidopropyl trimethoxysilane, 3-ureidopropyl triethoxysilane, N-ethoxycarbonyl-3-aminopropyl trimethoxysilane, N-ethoxycarbonyl-3-aminopropyl triethoxysilane, N-triethoxysilylpropyl triethylenetriamine, N-trimethoxysilylpropyl triethylenetriamine, vinyl trimethoxysilane, Silane coupling agents include 3-(3-trimethoxysilyl)propyl)isocyanurate, 3-isocyanatepropyltriethoxysilane and the like. When using a bonding aid, based on the viewpoint of exhibiting good resistance to AC image sticking, the amount of the bonding aid used is preferably 0.1 to 30 parts by weight, and more preferably 0.1 to 20 parts by weight, relative to 100 parts by weight of the total amount of the polymer used in the liquid crystal alignment agent.

[0170] Cross-linking compounds

[0171] For the aforementioned cross-linking compound, based on the viewpoint of exhibiting good resistance to AC image sticking and effectively improving film strength, it may be a compound having an ethylene oxide group, a propylene oxide group, at least one group selected from the group consisting of a group represented by the following formula (E1) and a group represented by the following formula (E2), or a compound selected from the compounds represented by the following formula (E3).

[0172]

[0173] In formula (E1), G1 and G2 each independently represent a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or -CH2-OH. In formula (E2), G3 represents an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, or an alkynyl group having 2 to 6 carbon atoms. G4 represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, or an alkynyl group having 2 to 6 carbon atoms. In formula (E3), G5 represents a (g1+g2)-valent organic group containing an aromatic ring. G6 represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. gl represents an integer from 1 to 6, and g2 represents an integer from 0 to 4.

[0174] In formula (E3), the (g1+g2)-valent organic group having an aromatic ring represented by G5 may include a (g1+g2)-valent aromatic hydrocarbon group having a carbon number of 6 to 30, an aromatic hydrocarbon group having a carbon number of 6 to 30 directly or through a linking group, or a (g1+g2)-valent group having an aromatic heterocycle. The aromatic hydrocarbon may be, for example, benzene or naphthalene. The aromatic heterocycle may be exemplified by the above-mentioned specific nitrogen-containing atom structure. The linking group may include an alkylene group having a carbon number of 1 to 10 or a group that removes a hydrogen atom from the alkylene group, or a divalent or trivalent cyclohexane, etc. Among them, any hydrogen atom of the alkylene group may also be substituted by an organic group such as a fluorine atom or a trifluoromethyl group. In formula (E3), the alkyl group having 1 to 5 carbon atoms represented by G6 may be methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, sec-butyl, t-butyl or n-pentyl.

[0175] Compounds with ethylene oxide

[0176] Specific examples of compounds having an oxirane group include N,N,N′,N′-tetraepoxypropyl-m-xylene diamine, 1,3-bis(N,N-diepoxypropylaminomethyl)cyclohexane, N,N,N′,N′-tetraepoxypropyl-4,4′-diaminodiphenylmethane, N,N,N′,N′-tetraepoxypropyl-p-phenylenediamine, and compounds containing nitrogen atoms such as those shown in the following formulas (E4) to (E6).

[0177]

[0178] Compounds having propylene oxide groups

[0179] Specific examples of the compound having an propylene oxide group include compounds represented by the following formula (E7) to formula (E16).

[0180]

[0181]

[0182]

[0183] In formula (E15), R represents The “*” represents the bonding position.

[0184] Compounds having a group represented by formula (E1)

[0185] Specific examples of the compound having a group represented by the formula (E1) include compounds represented by the following formulas (E1-1) to (E1-12).

[0186]

[0187]

[0188]

[0189] Compounds having a group represented by formula (E2)

[0190] Specific examples of the compound having a group represented by formula (E2) include compounds represented by the following formulas (E2-1) to (E2-4).

[0191]

[0192]

[0193] Compounds having a group represented by formula (E3)

[0194] Specific examples of the compound having a group represented by formula (E3) include compounds represented by the following formulas (E3-1) to (E3-10).

[0195]

[0196]

[0197] In the liquid crystal alignment agent of the present invention, based on the total amount of the polymer in the liquid crystal alignment agent being 100 parts by weight, the amount of the crosslinking compound used is preferably 0.5 parts by weight to 20 parts by weight. In particular, based on the viewpoint of the crosslinking reaction and the good resistance to AC image sticking, the amount of the crosslinking compound used is more preferably 1 part by weight to 15 parts by weight.

[0198] Compounds that promote imidization

[0199] The aforementioned compound for promoting imidization is preferably a compound having a basic site (for example: a primary amine group, an aliphatic heterocycle (such as a pyrrolidine skeleton), an aromatic heterocycle (such as an imidazole ring or an indole ring), or a guanidine group, etc.) (except for the above-mentioned cross-linking compound and the close-fitting aid), or a compound that produces the basic site when calcined. More preferably, the compound that promotes imidization is a compound that produces the basic site when calcined, and a specific example thereof may be an amino acid in which a part or all of the basic sites possessed by the amino acid are protected. Specific examples of the above-mentioned amino acids include glycine, alanine, cysteine, methionine, asparagine, glutamic acid, valine, leucine, phenylalanine, tyrosine, tryptophan, proline, hydroxyproline, arginine, histidine, lysine, or ornithine. For the purpose of promoting the imidization compound, a more preferable specific example is N-α-(9-fluorenylmethoxycarbonyl)-N-τ-(tert-butoxycarbonyl)-L-histidine.

[0200] Liquid crystal alignment film and method for manufacturing liquid crystal display component

[0201] The liquid crystal alignment film of the present invention is obtained from the aforementioned liquid crystal alignment agent. The liquid crystal alignment film of the present invention can be used as a horizontal alignment type or a vertical alignment type (VA type) liquid crystal alignment film, and is suitable for a liquid crystal alignment film of a horizontal alignment type liquid crystal display component such as an IPS mode or a FFS mode. The liquid crystal display component of the present invention has the aforementioned liquid crystal alignment film. The liquid crystal display component of the present invention can be produced, for example, by the following steps (1) to (4) or steps (1) to (2) and step (4).

[0202] Step (1): Applying a liquid crystal alignment agent onto a substrate

[0203] The liquid crystal alignment agent of the present invention is applied to one side of a substrate provided with a patterned transparent conductive film by a suitable coating method such as roller coating, spin coating, printing or inkjet. There is no particular limitation on the substrate, which only needs to be a highly transparent substrate. A glass substrate or a silicon nitride substrate can also be used in combination with a plastic substrate such as an acrylic substrate or a polycarbonate substrate. Secondly, in a reflective liquid crystal display component, if only a single-sided substrate is used, an opaque material such as a silicon wafer can also be used, and the electrode used can also be a light-reflecting material such as aluminum. Furthermore, when making an IPS-type or FFS-type liquid crystal component, a comb-tooth type uses an electrode substrate composed of a patterned transparent conductive film or metal film and an opposing substrate without an electrode.

[0204] The method of coating the liquid crystal alignment agent on the substrate to form a film may include screen printing, lithography, flexographic printing, inkjet method or spray coating method, etc. Among them, the film forming method is preferably coating by inkjet method.

[0205] Step (2): calcining the coated liquid crystal alignment agent

[0206] Step (2) is a step of calcining the liquid crystal alignment agent applied on the substrate to form a film. After the liquid crystal alignment agent is applied on the substrate, the solvent can be evaporated by heating means such as a hot plate, a heat circulation oven or an IR (infrared) oven, or thermal imidization of polyamic acid or polyamic acid ester can be performed. The drying and calcining steps performed after the liquid crystal alignment agent of the present invention has been applied can be selected at any temperature and time, and multiple drying or calcining steps can be performed. The drying temperature can be, for example, 40°C to 180°C. From the perspective of shortening the process, it can be performed at 40°C to 150°C. The drying time is not particularly limited, and it can be, for example, 1 minute to 10 minutes or 1 minute to 5 minutes. When thermal imidization of polyamic acid or polyamic acid ester is performed, after the aforementioned drying step, a calcination step can be further performed at a temperature of, for example, 150°C to 300°C or 150°C to 250°C. The calcination time is not particularly limited, and may be 5 to 40 minutes or 5 to 30 minutes. If the film after calcination is too thin, the reliability of the liquid crystal display device will be reduced, so the film thickness is preferably 5 nm to 300 nm, and more preferably 10 nm to 200 nm.

[0207] Step (3): Align the film obtained in step (2)

[0208] Step (3) is to perform an alignment treatment on the film obtained in step (2) as appropriate. In other words, in a horizontal alignment type liquid crystal display component such as an IPS mode or an FFS mode, the coating film is subjected to an alignment treatment to impart alignment capability. On the other hand, in a vertical alignment type liquid crystal display component such as a VA mode or a PSA mode, the formed coating film can be used directly as a liquid crystal alignment film, but the coating film can also be subjected to an alignment treatment to impart alignment capability. The alignment treatment of the liquid crystal alignment film can include a friction treatment method or a photo-alignment treatment method, preferably a photo-alignment treatment method. The photo-alignment treatment method can include a method in which the surface of the above-mentioned film-like object is irradiated with radiation that has been deflected in a certain direction, and, as appropriate, preferably heated at a temperature of 150°C to 250°C to impart liquid crystal alignment (also referred to as liquid crystal alignment capability). The radiation can use ultraviolet rays or visible light with a wavelength of 100nm to 800nm. Among them, the radiation is preferably ultraviolet light having a wavelength of 100 nm to 400 nm, and more preferably ultraviolet light having a wavelength of 200 nm to 400 nm.

[0209] The radiation dose can be 1mJ / cm 2Up to 10,000mJ / cm 2 , preferably 100mJ / cm 2 Up to 5,000mJ / cm 2 , preferably 100 mJ / cm 2 Up to 1500mJ / cm 2 , and preferably 100 mJ / cm 2 Up to 1000mJ / cm 2 When using a general liquid crystal alignment agent, the light exposure for the alignment treatment is 100mJ / cm 2 Up to 5000mJ / cm 2 However, the liquid crystal alignment agent of the present invention can obtain a liquid crystal alignment film in which the variation (non-uniformity) of the liquid crystal alignment within the film surface is effectively suppressed even if the amount of light irradiation in the alignment treatment is reduced. When irradiating radiation, in order to improve the liquid crystal alignment, the substrate of the aforementioned film-like object can be heated at 50°C to 250°C while irradiating. The liquid crystal alignment film produced in this way can stably align the liquid crystal molecules in a certain direction. Secondly, the liquid crystal alignment film that has been irradiated with polarized radiation in the aforementioned method can be contact-treated with a solvent, or the liquid crystal alignment film that has been irradiated with radiation can be heat-treated.

[0210] The solvent used in the above-mentioned contact treatment is not particularly limited, and it only needs to be able to dissolve the decomposition products generated from the film after irradiation with radiation. Specific examples include water, methanol, ethanol, 2-propanol, acetone, methyl ethyl ketone, 1-methoxy-2-propanol, 1-methoxy-2-propanol acetate, butyl cellulose, ethyl lactate, methyl lactate, diacetone alcohol, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, propyl acetate, butyl acetate, or cyclohexyl acetate. Among them, based on the viewpoint of versatility and safety, water, 2-propanol, 1-methoxy-2-propanol or ethyl lactate are preferred, and water, 1-methoxy-2-propanol or ethyl lactate are more preferred. The solvent can be used alone or in combination.

[0211] The temperature at which the coating film irradiated with radiation is subjected to heat treatment is preferably 50° C. to 300° C., and more preferably 120° C. to 250° C. The time for the heat treatment is preferably 1 minute to 30 minutes.

[0212] Step (4): Making liquid crystal cells

[0213] Two liquid crystal alignment film substrates formed as described above are prepared, and liquid crystal is arranged between the two substrates arranged facing each other. For example, the following two methods can be cited. In the first method, the two substrates are arranged facing each other with a gap (cell gap) between them in a manner that the liquid crystal alignment films face each other. Then, the peripheral portions of the two substrates are bonded together with a sealant, and then the liquid crystal composition is injected and filled into the cell gap separated by the substrate surface and the sealant, and after it contacts the film surface, the injection hole is sealed.

[0214] The second method is called ODF (One Drop Fill). A sealant such as a UV-curable sealant is applied to a predetermined position of one of the two substrates on which a liquid crystal alignment film has been formed, and then a liquid crystal composition is dripped at multiple predetermined positions on the surface of the liquid crystal alignment film. Then, the other substrate is attached in a manner that the liquid crystal alignment films face each other, and the liquid crystal composition is pushed on the entire surface of the substrate so that it contacts the film surface. Next, ultraviolet light is irradiated on the entire surface of the substrate to harden the sealant. When any of the aforementioned methods is performed, it is preferred to further heat the liquid crystal composition used to a temperature at which it becomes an isotropic phase, and then slowly cool it to room temperature to remove the flow alignment during liquid crystal filling. Secondly, when the coating is subjected to friction treatment, the two substrates are arranged to face each other at a predetermined angle with the friction directions of each coating, for example, in a perpendicular or anti-parallel manner. The sealant may be, for example, an epoxy resin containing a hardener and alumina balls as spacers. Examples of the liquid crystal composition include nematic liquid crystal and smectic liquid crystal, and nematic liquid crystal is preferred.

[0215] If necessary, a polarizing plate can be attached to the outer surface of the liquid crystal cell to obtain a liquid crystal display device. The polarizing plate attached to the outer surface of the liquid crystal cell can be a polarizing film called "H film" that stretches polyvinyl alcohol and absorbs iodine. It can be a polarizing plate sandwiched by a cellulose acetate protective film, or a polarizing plate composed of the H film itself.

[0216] The following embodiments are used to illustrate the application of the present invention, but they are not used to limit the present invention. Anyone skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0217] none DETAILED DESCRIPTION

[0218] Preparation of polymer (A)

[0219] Synthesis Example A-1-1

[0220] A nitrogen inlet, a stirrer, a condenser and a thermometer were set on a 500 ml four-necked conical flask, and nitrogen was introduced. Then, 1.215 g (0.0035 mol) of the compound (a2-1-1) represented by the formula (A21-1), 6.57 g (0.0225 mol) of the diamine compound (a2-2-3) represented by the formula (A22-2), 3.66 g (0.015 mol) of the diamine compound (a2-3-2) represented by the formula (A23-2), 1.784 g (0.009 mol) of 4,4′-diaminodiphenylmethane (a2-4-1) and 80 g of N-methyl-2-pyrrolidone (hereinafter referred to as NMP) were added, and stirred at room temperature until dissolved. Next, 11.1 g (0.05 mol) of a diamine compound (a1-1-1) as shown in formula (A11-1) and 20 g of NMP were added and reacted at room temperature for 2 hours. After the reaction, the reaction solution was poured into 1500 ml of water to precipitate the polymer, the obtained polymer was filtered, and the steps of washing and filtering were repeated three times with methanol. After that, the product was placed in a vacuum oven and dried at a temperature of 60°C to obtain the polymer (A-1-1) of Synthesis Example A-1-1, whose formula is shown in Table 1.

[0221] Synthesis Examples A-1-2 to A-1-6 and Comparative Synthesis Examples A′-1-1 to A′-1-7

[0222] Synthesis Examples A-1-2 to A-1-6 and Comparative Synthesis Examples A′-1-1 to Comparative Synthesis Examples A′-1-7 use the same preparation method as the method for making the polymer (A-1-1) of Synthesis Example A-1-1, the difference being that Synthesis Examples A-1-2 to A-1-6 and Comparative Synthesis Examples A′-1-1 to Comparative Synthesis Examples A′-1-7 change the type and amount of raw materials in the polymer, and the formula is shown in Table 1 and will not be further described here.

[0223] Synthesis Example A-2-1

[0224] A nitrogen inlet, a stirrer, a condenser and a thermometer were set on a 500 ml four-necked conical flask, and nitrogen was introduced. Then, 1.215 g (0.0035 mol) of the compound (a2-1-1) represented by the formula (A21-1), 6.57 g (0.0225 mol) of the diamine compound (a2-2-3) represented by the formula (A22-2), 3.66 g (0.015 mol) of the diamine compound (a2-3-2) represented by the formula (A23-2), 1.784 g (0.009 mol) of 4,4′-diaminodiphenylmethane (a2-4-1) and 80 g of NMP were added, and stirred at room temperature until dissolved. Next, 11.1 g (0.05 mol) of the diamine compound (a1-1-1) represented by the formula (A11-1) and 20 g of NMP were added. After reacting at room temperature for 6 hours, 97 grams of NMP, 2.55 grams of acetic anhydride and 19.75 grams of pyridine were added, the temperature was raised to 60°C, and stirring was continued for 2 hours to carry out imidization reaction. After the reaction was completed, the reaction solution was poured into 1500 ml of water to precipitate the polymer. Then, the obtained polymer was filtered, and the washing and filtering with methanol were repeated three times, placed in a vacuum oven, and dried at a temperature of 60°C to obtain the polymer (A-2-1) of Synthesis Example A-2-1, whose formula is shown in Table 1.

[0225] Synthesis Example A-2-2

[0226] Synthesis Example A-2-2 uses the same preparation method as the preparation method of the polymer (A-2-1) in Synthesis Example A-2-1, the difference is that Synthesis Example A-2-2 changes the type and amount of raw materials in the polymer. Its formula is shown in Table 1 and is not further described here.

[0227] Table 1

[0228]

[0229] a1-1-1 The compound represented by formula (A11-1)

[0230] a1-2-1 Pyromellitic dianhydride

[0231] a1-2-2

[0232] a2-1-1 Compound represented by formula (A21-1)

[0233] a2-1-2 Compound represented by formula (A21-2)

[0234] a2-1-3 Compound represented by formula (A21-3)

[0235] a2-1-4 Compound represented by formula (A21-4)

[0236] a2-2-1 Compound represented by formula (A22-4)

[0237] a2-2-2 Compound represented by formula (A22-7)

[0238] a2-2-3 Compound represented by formula (A22-2)

[0239] a2-2-4 Compound represented by formula (A22-3)

[0240] a2-3-1 p-phenylenediamine

[0241] a2-3-2 A compound as represented by formula (A23-1), wherein Y 31 represents a group as shown in formula (A23-3-7), n is 2; and Y 32 Represents hydrogen atom

[0242] a2-4-1 4,4'-diaminodiphenylmethane

[0243] a2-4-2 4,4'-diaminodiphenyl ether

[0244] Preparation of polymer (B)

[0245] Synthesis Example B-1-1 to Synthesis Example B-1-7

[0246] Synthesis Examples B-1-1 to B-1-7 are prepared by the same method as the method for preparing the polymer (A-1-1) of Synthesis Example A-1-1, except that the types and amounts of raw materials used in the polymers are changed in Synthesis Examples B-1-1 to B-1-7. The formulas are shown in Table 2, and are not described here.

[0247] Synthesis Example B-2-1 to Synthesis Example B-2-2

[0248] Synthesis Example B-2-1 to Synthesis Example B-2-2 are prepared by the same method as the preparation method of the polymer (A-2-1) of Synthesis Example A-2-1, except that the types and amounts of raw materials used in the polymers are changed from Synthesis Example B-2-1 to Synthesis Example B-2-2. The formulas are shown in Table 2, which are not described in detail here.

[0249] Table 2

[0250]

[0251] b1-1-1

[0252] b1-1-2 The compound represented by formula (IV)

[0253] b2-1-1 4,4'-Diaminodiphenylamine

[0254] b2-1-2 A compound as shown in formula (B21-9), wherein the amino groups on both sides are bonded to the para position of the benzene ring

[0255] b2-1-3 p-phenylenediamine

[0256] b2-1-4 1,2-bis(4-aminophenoxy)ethane

[0257] Preparation of liquid crystal alignment agent, liquid crystal alignment film and liquid crystal display component

[0258] Example 1

[0259] Weigh 50 parts by weight of the polymer (A-1-1) prepared in Synthesis Example A-1-1, 50 parts by weight of the polymer (B-1-1) prepared in Synthesis Example B-1-1, and 2000 parts by weight of NMP (C-1), and stir and mix them at room temperature to obtain the liquid crystal alignment agent of Example 1.

[0260] The liquid crystal alignment agent prepared above is spin-coated on a glass substrate, and a pixel electrode is formed on the glass substrate, wherein the pixel electrode is an IPS driving electrode having a pair of ITO electrodes (electrode width is 10 μm, electrode interval is 10 μm, and electrode height is 50 nm), and the pair of ITO electrodes have a comb-like shape, and the comb-like parts of each other are arranged in a separated and biting manner. Then, the glass substrate coated with the liquid crystal alignment agent is dried on a hot plate at 80°C for 3 minutes, and then baked in a hot air circulation oven at 250°C for 30 minutes to form a coating film with a thickness of 100 nm.

[0261] After irradiating the coating surface with ultraviolet light having a wavelength of 254 nm through a polarizing plate, the substrate was baked in a hot air circulation oven at 250° C. for 30 minutes to obtain a substrate having a liquid crystal alignment film. Similarly, a coating film was formed on an opposing substrate and an alignment treatment was applied, wherein the opposing substrate was a glass substrate having no electrode formed thereon but having a columnar spacer having a height of 4 μm.

[0262] The above two substrates are a set, and a sealant is printed on one of them, and the other is bonded in a manner that it faces the liquid crystal alignment film and the alignment direction is 0°, and then the sealant is hardened to obtain an empty cell. This empty cell is injected with liquid crystal MLC-2041 (Merck) by a reduced pressure injection method, and the injection port is sealed to obtain the liquid crystal display component of Example 1. The obtained liquid crystal display component is evaluated in the following evaluation method, and the results are shown in Table 3, among which the detection method of the brightness change rate after driving will be described later.

[0263] Examples 2 to 10 and Comparative Examples 1 to 7

[0264] Examples 2 to 10 and Comparative Examples 1 to 7 use the same preparation method for the liquid crystal alignment agent, liquid crystal alignment film and liquid crystal display component as that of Example 1, the difference being that Examples 2 to 10 and Comparative Examples 1 to 7 change the type and usage of raw materials in the liquid crystal alignment agent, and their formulas and evaluation results are shown in Table 3, respectively, which will not be further described here.

[0265] Table 3

[0266]

[0267] C-1 N-methyl-2-pyrrolidone (NMP)

[0268] C-2 Ethylene glycol n-butyl ether

[0269] C-3 N, N-dimethylacetamide

[0270] Evaluation method

[0271] Brightness change rate after driving

[0272] Polarizing plates were attached perpendicularly to the top and bottom surfaces of the liquid crystal display components prepared in the aforementioned Examples 1 to 32 and Comparative Examples 1 to 5. The liquid crystal display components attached with polarizing plates were placed under 10000 cd / m 2 The backlight was placed on the LCD, and the brightness in the dark state (L0) was observed using a brightness meter PR-788. Then, the liquid crystal was driven at room temperature and 5V AC voltage for 1 hour, and when the voltage of the liquid crystal display component was disconnected, the brightness in the dark state (L1) was observed using the above method. The brightness change rate was calculated using the following formula, and the brightness change rate of the liquid crystal display component after driving was evaluated based on the following benchmarks.

[0273]

[0274] ※: Brightness change rate after driving <1%.

[0275] ◎: 1%≤Brightness change rate after driving<2%.

[0276] ○: 2%≤Brightness change rate after driving<3%.

[0277] △: 3%≤Brightness change rate after driving<5%.

[0278] ×: Brightness change rate after driving ≥5%.

[0279] From the results in Table 3, it can be seen that if the polymer (A) of the liquid crystal alignment agent of the present invention does not contain the structures shown in formula (I) and formula (II), the brightness change rate of the liquid crystal display device after driving of the liquid crystal alignment film formed by the liquid crystal alignment agent is not good. Wherein, in formula (I), when A1 and A2 represent a divalent group formed by removing two hydrogen atoms from the ring part of a benzene ring, a pyridine ring or a pyrimidine ring, wherein the ring part may have a substituent, and A1 and A2 are the same, and Z1 represents When n represents an integer from 1 to 5, the liquid crystal alignment film prepared by using the liquid crystal alignment agent can further reduce the brightness change rate of the liquid crystal display element after driving. 21 With Y 22 When they independently represent -O- or -S-, the liquid crystal alignment film prepared by using the liquid crystal alignment agent can further reduce the brightness change rate of the liquid crystal display component after driving.

[0280] In addition, when the liquid crystal alignment agent of the present invention contains a polymer (B), if the tetracarboxylic dianhydride component (b1) contains a tetracarboxylic dianhydride compound (b1-1), the liquid crystal alignment film prepared using this liquid crystal alignment agent can further reduce the brightness change rate of the liquid crystal display component after driving; if the diamine component (b2) contains a diamine compound (b2-1), the liquid crystal alignment film prepared using this liquid crystal alignment agent can further reduce the brightness change rate of the liquid crystal display component after driving.

[0281] It should be added that, although the present invention uses specific compounds, compositions, reaction conditions, processes, analysis methods or specific instruments as examples to illustrate the liquid crystal alignment agent, liquid crystal alignment film and liquid crystal display component used in the photo-alignment method of the present invention, anyone with common knowledge in the technical field to which the present invention belongs can know that the present invention is not limited to this. Without departing from the spirit and scope of the present invention, the liquid crystal alignment agent, liquid crystal alignment film and liquid crystal display component used in the photo-alignment method of the present invention may also use other compounds, compositions, reaction conditions, processes, analysis methods or instruments.

[0282] Although the present invention has been disclosed as above in the form of an implementation method, it is not intended to limit the present invention. Anyone with ordinary knowledge in the technical field to which the present invention belongs can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be determined by the scope of the attached patent application.

Claims

1. A liquid crystal alignment agent for a photo-alignment method, characterized in that: Include: The polymer (A) is at least one polymer selected from the group consisting of a polyimide precursor and an imidized polymer of the polyimide precursor, wherein the polyimide precursor comprises the structures shown in the following formula (I) and formula (II): In the formula (I), X1 represents the structure shown in the following formula (I-1); X2 represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms; A1 and A2 represent a divalent aromatic ring group, and the ring portion may have a substituent, wherein A1 and A2 are the same; Y 11 represent R1 represents a group that is released by heat; Y 12 represents a single bond, an oxygen atom or a sulfur atom; Z1 represents a divalent organic group having at least one of a chain hydrocarbon structure and an alicyclic hydrocarbon structure and having a carbon number of 1 to 15: In formula (I-1), X 11 , X 12 , X 13 With X 14 Each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, a monovalent organic group having 1 to 6 carbon atoms and containing a fluorine atom, or a phenyl group, 11 To X 14 are the same or different, and X 11 , X 12 , X 13 With X 14 At least one of is not a hydrogen atom; In the formula (II), X1 and X2 are as defined above; Y 21 Represents a single bond, -O-, -S-, -SS-, -SO2-, -CO-, -C(CH3)2-, -C(CF3)2-, -(CH2) m -、-O-(CH2) m -O- or -S-(CH2) m -S-, and m represents an integer from 1 to 12; and Y 22 represents a single bond, -O-, -S-, -CO-, -C(CH3)2-, -C(CF3)2-, or an alkylene group having 1 to 10 carbon atoms; and Solvent (C).

2. The liquid crystal alignment agent for photo-alignment method according to claim 1, characterized in that: X1 represents a structure as shown in formula (I-1-1):

3. The liquid crystal alignment agent for photo-alignment method according to claim 1, characterized in that: A1 and A2 represent a divalent group formed by removing two hydrogen atoms from a ring portion of a benzene ring, a pyridine ring or a pyrimidine ring, the ring portion may have a substituent, and A1 and A2 are the same; Z1 represents And n represents an integer from 1 to 5.

4. The liquid crystal alignment agent for photo-alignment method according to claim 1, characterized in that: Y 21 With Y 22 Each independently represents -O- or -S-.

5. The liquid crystal alignment agent for photo-alignment method according to claim 1, characterized in that: Also includes: The polymer (B) is at least one polymer selected from the group consisting of a polyimide precursor and an imidized polymer of the polyimide precursor, wherein the polyimide precursor of the polymer (B) does not contain the structures shown in formula (I) and formula (II).

6. The liquid crystal alignment agent for photo-alignment method according to claim 5, characterized in that: The polyimide precursor of the polymer (B) is obtained by reacting a tetracarboxylic dianhydride component (b1) and a diamine component (b2), and the tetracarboxylic dianhydride component (b1) comprises a structure shown in the following formula (III): In the formula (III), Z 11 represents a single bond; and “*” represents a bonding position.

7. The liquid crystal alignment agent for photo-alignment method according to claim 5, characterized in that: The polyimide precursor of the polymer (B) is obtained by reacting a tetracarboxylic dianhydride component (b1) and a diamine component (b2), and the diamine component (b2) comprises a diamine compound having at least one nitrogen-containing atom structure selected from the group consisting of a nitrogen-containing heterocyclic ring, a secondary amine group, and a tertiary amine group.

8. A liquid crystal alignment film, characterized in that: The liquid crystal alignment agent for photo-alignment method according to any one of claims 1 to 7 is used.

9. A liquid crystal display component, characterized in that: It comprises the liquid crystal alignment film as claimed in claim 8.

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