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

Abstract

Provided is a liquid crystal alignment film which has stable in-plane contrast in a low-irradiation-amount region and has little surface irregularities. A liquid crystal aligning agent contains a component (A) and a component (B). Component (A): a polyimide (A) having a repeating unit (a1) represented by formula (1), a repeating unit (a2) represented by formula (2), and an imidized structural unit of at least one of these repeating units, the total of the repeating units (a1) and the imidized structural units of the repeating units (a1) being 10-40 mol% of the total repeating units of the polyimide (A). The total of the repeating units (a2) and the imidized structural units of the repeating units (a2) is 60-90 mol% of the total repeating units of the polyimide (A). Component (B): a polyamic acid (B) having a repeating unit (b1) represented by formula (5). (In the formula, the meaning of each symbol is as defined in the description. > # imgabs0 #

Description

Technical Field

[0001] The present invention relates to a liquid crystal alignment agent, a liquid crystal alignment film and a liquid crystal display element. Background Art

[0002] Liquid crystal display devices are widely used as display units for personal computers, smart phones, mobile phones, televisions, etc. Liquid crystal display devices usually have: a liquid crystal layer, which is sandwiched between a display element substrate and a color filter substrate; pixel electrodes and common electrodes, which apply an electric field to the liquid crystal layer; an orientation film, which controls the orientation of liquid crystal molecules in the liquid crystal layer; and a thin film transistor (TFT: Thin Film Transistor), which converts the electrical signal supplied to the pixel electrode; etc. As a driving method for liquid crystal molecules, known are: longitudinal electric field methods such as TN (Twisted Nematic) method and VA (Vertical Alignment) method; and transverse electric field methods such as IPS (In Plane Switching) driving method and FFS (Fringe Field Switching) driving method.

[0003] The most popular liquid crystal alignment film in industry is made by performing a so-called rubbing treatment, which is to rub the surface of a film formed on an electrode substrate and composed of polyamic acid and / or a polyimide imidized therefrom in one direction using a cloth such as cotton, nylon, or polyester. Rubbing treatment is a simple and productive industrially useful method. However, with the high performance, high precision, and large-scale development of liquid crystal display elements, various problems such as surface damage, dust, mechanical force, and static electricity caused by the rubbing treatment of the alignment film, and then the unevenness within the alignment treatment surface have become apparent. As an alignment treatment method that replaces the rubbing treatment, a photo-alignment method that imparts liquid crystal alignment ability by irradiating polarized radiation is known. As far as the photo-alignment method is concerned, a method utilizing a photoisomerization reaction, a method utilizing a photocrosslinking reaction, a method utilizing a photodecomposition reaction, and the like have been proposed (for example, refer to non-patent document 1, patent documents 1 to 4).

[0004] In recent years, small display terminals such as high-definition tablet PCs and car navigation have become the mainstream, and the demand for high-quality liquid crystal display elements has been further improved than before. In addition, when using the photo-orientation method for orientation treatment, the amount of light irradiation is a factor that affects energy consumption and production speed, so it is preferred to be able to perform the orientation treatment with a small amount of light irradiation.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Laid-Open No. 9-297313

[0008] Patent Document 2: Japanese Patent Application Publication No. 2004-206091

[0009] Patent Document 3: WO2013 / 157586

[0010] Patent Document 4: WO2016 / 152928

[0011] Non-patent literature

[0012] Non-patent document 1: "Functional Materials", November 1997, Vol. 17, No. 11, pp. 13-22 Summary of the invention

[0013] Problems to be solved by the invention

[0014] The present inventors have conducted research and found that a liquid crystal alignment film obtained by using a conventional liquid crystal alignment agent including a first polyamic acid and a second polyamic acid obtained by using substituted cyclobutanetetracarboxylic dianhydride as raw materials has a low thermal conductivity of less than 450 mJ / cm 2 The in-plane contrast in the low-irradiation area is not necessarily stable.

[0015] Therefore, in order to stabilize the in-plane contrast, the raw material components of the first polyamic acid were reviewed, and a liquid crystal aligning agent containing polyimide and polyamic acid was re-examined. As a result, fine irregularities were generated on the surface of the liquid crystal aligning film this time.

[0016] On the other hand, with regard to recent liquid crystal display elements, as the number of pixels of liquid crystal display elements increases and the pixel size decreases, the pixel electrode becomes a further fine structure, and the concave-convex density per unit area of ​​the formation surface of the pixel electrode tends to become higher. The liquid crystal alignment film is usually formed by applying a liquid crystal alignment agent to the pixel electrode, but from the perspective of improving the display quality level, it is more preferred that the film thickness of the obtained coating film is uniform, and it is further preferred that the film surface of the liquid crystal alignment film has fewer concave-convex surfaces. In the composition studied above, it cannot be said that the display characteristics required in the future will be met, which may lead to a reduction in the display quality level.

[0017] Therefore, in view of the above situation, the object of the present invention is to provide a method for obtaining a 2 A liquid crystal aligning agent for a liquid crystal aligning film having a stable in-plane contrast ratio in a low irradiation amount region, the liquid crystal aligning film, and a liquid crystal display element using the liquid crystal aligning film.

[0018] In addition, the object of the present invention is to provide a liquid crystal alignment agent that can obtain a liquid crystal alignment film with less surface unevenness in a liquid crystal alignment film formed by a specific liquid crystal alignment agent containing polyimide and polyamic acid obtained by using substituted cyclobutanetetracarboxylic dianhydride or its derivatives as raw materials, the liquid crystal alignment film, and a liquid crystal display element using the liquid crystal alignment film.

[0019] Solutions for solving problems

[0020] The present inventors have conducted intensive studies and have found that the above-mentioned technical problems can be solved by using a liquid crystal aligning agent containing specific components, thereby completing the present invention.

[0021] Specifically, the present invention has the following aspects.

[0022] A liquid crystal aligning agent characterized by containing the following (A) component and (B) component.

[0023] Component (A): a polyimide (A) comprising either or both of a repeating unit (a1) represented by the following formula (1) and an imidized structural unit of the repeating unit (a1), and either or both of a repeating unit (a2) represented by the following formula (2) and an imidized structural unit of the repeating unit (a2), wherein the total amount of the repeating unit (a1) and the imidized structural unit of the repeating unit (a1) is 10 to 40 mol % of all the repeating units of the polyimide (A), and the total amount of the repeating unit (a2) and the imidized structural unit of the repeating unit (a2) is 60 to 90 mol % of all the repeating units of the polyimide (A).

[0024] (B) Component: a polyamic acid (B) having a repeating unit (b1) represented by the following formula (5).

[0025]

[0026] (R and Z each independently represent a hydrogen atom or a monovalent organic group.)

[0027]

[0028] (In formula (2), R and Z have the same meanings as in the case of formula (1). Y2 represents a divalent organic group represented by the following formula (2m).

[0029]

[0030] (In formula (2m), any hydrogen atom on the benzene ring may be substituted with a halogen atom or a monovalent organic group. * represents a bonding bond.)

[0031]

[0032] (In the above formula (5), X5 is a tetravalent organic group, and Y5 is a divalent organic group. Z has the same meaning as Z in the above formula (1).)

[0033] It should be noted that, in the entire specification, the following terms and abbreviations have the following meanings: Halogen atoms include fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, and the like.

[0034] * In any case, it represents a bond. In addition, Boc represents a tert-butyloxycarbonyl group, and Fmoc represents a 9-fluorenylmethoxycarbonyl group.

[0035] Effects of the Invention

[0036] According to the present invention, it is possible to provide a method for obtaining a heat release of less than 450 mJ / cm 2 A liquid crystal alignment agent for a liquid crystal alignment film having a stable in-plane contrast in a low-irradiation area, the liquid crystal alignment film, and a liquid crystal display element using the liquid crystal alignment film. In addition, a liquid crystal alignment agent for a liquid crystal alignment film having less surface unevenness in a liquid crystal alignment film formed from a specific liquid crystal alignment agent comprising polyimide and polyamic acid obtained by using substituted cyclobutanetetracarboxylic dianhydride or a derivative thereof as raw materials, the liquid crystal alignment film, and a liquid crystal display element using the liquid crystal alignment film can be provided.

[0037] The mechanism of obtaining the above-mentioned effect of the present invention is not necessarily clear, but it can be considered that the following is one of the reasons. It is believed that: by introducing a rigid skeleton and a component with high solubility into polyimide, good orientation uniformity can be obtained, and the cohesion of polymer can be suppressed. Therefore, even when polyamic acid is mixed in the above-mentioned polyimide, a film with flat surface can be obtained, so the above-mentioned effect is obtained. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 This is a schematic cross-sectional view of an example of a lateral electric field liquid crystal display element including a liquid crystal aligning film obtained from the liquid crystal aligning agent of the present invention.

[0039] Figure 2 This is a schematic cross-sectional view of another example of a lateral electric field liquid crystal display element including a liquid crystal aligning film obtained from the liquid crystal aligning agent of the present invention. DETAILED DESCRIPTION

[0040] <Polyimide (A)>

[0041] The liquid crystal aligning agent of this invention contains a polyimide (A).

[0042] The polyimide (A) has one or both of the repeating unit (a1) represented by the above formula (1) and the imidized structural unit of the repeating unit (a1). The polyimide (A) may be composed of one or two or more of these repeating units.

[0043] In the above formula (1), R and Z each independently represent a hydrogen atom or a monovalent organic group.

[0044] Examples of the monovalent organic group in R and Z in the above formula (1) include a monovalent hydrocarbon group having 1 to 20 carbon atoms, -O-, -S-, -CO-, -COO-, -COS-, -NR- 3 -、-CO-NR 3 -、-Si(R 3 )2-(where R 3 is a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms. 3 In the case of 3 The monovalent organic group in R and Z in the above formula (1) is preferably an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an alkynyl group having 2 to 10 carbon atoms, a Boc group, or a Fmoc group, and more preferably an alkyl group having 1 to 3 carbon atoms, and still more preferably a methyl group.

[0045] From the viewpoint of appropriately obtaining the effects of the present invention, R and Z are each independently preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and more preferably a hydrogen atom or a methyl group.

[0046] The polyimide (A) of the present invention has one or both of the repeating unit (a2) represented by the above formula (2) and the imidized structural unit of the repeating unit (a2). The polyimide (A) may be composed of one or more of these repeating units.

[0047] Preferred embodiments of R and Z in the above formula (2) include the structures exemplified in the above formula (1), and more preferred embodiments are also the same as the structures exemplified in the above formula (1).

[0048] Any hydrogen atom on the benzene ring in the above formula (2m) is optionally substituted by a halogen atom (e.g., a fluorine atom, a chlorine atom, a bromine atom, an iodine atom) or a monovalent organic group (e.g., an alkyl group having 1 to 3 carbon atoms, an alkenyl group having 2 to 3 carbon atoms, an alkynyl group having 2 to 3 carbon atoms, a monovalent organic group having 1 to 3 carbon atoms containing a fluorine atom, etc.).

[0049] From the viewpoint of appropriately obtaining the effects of the present invention, the total amount of the repeating unit (a1) and the imidized structural unit of the repeating unit (a1) is 10 to 40 mol %, preferably 10 to 30 mol %, more preferably 10 to 20 mol % of all repeating units in the polyimide (A).

[0050] From the viewpoint of appropriately obtaining the effects of the present invention, the total amount of the repeating unit (a2) and the imidized structural unit of the repeating unit (a2) is 60 to 90 mol %, more preferably 70 to 90 mol %, and most preferably 80 to 90 mol % of all the repeating units possessed by the polyimide (A).

[0051] From the viewpoint of appropriately obtaining the effects of the present invention, the polyimide (A) may be a polyimide having at least one of the repeating unit (a1), the repeating unit (a2), and their imidized structural units, and further having at least one selected from the group consisting of a repeating unit (ar) represented by the following formula (Ar), a repeating unit (a2') represented by the following formula (2'), a repeating unit (a3) ​​represented by the following formula (3), and their imidized structural units. It should be noted that the repeating units (ar), (a2') to (a3), and their imidized structural units may be one type or two or more types.

[0052]

[0053] In the above formula (Ar), R and Z have the same meanings as in the above formula (1). Y2 represents a divalent organic group represented by the following formula (O) (excluding the divalent organic group represented by the above formula (2m)).

[0054] *-Ar-Q2-Ar-* (O)

[0055] In the above formula (O), Ar each independently represents a benzene ring, a biphenyl structure, or a naphthalene ring. Any hydrogen atom on the Ar ring may be substituted with a halogen atom or a monovalent organic group. Q2 represents -(CH2) n -(n is 2 to 18), or -(CH2) is substituted by any one of -O-, -C(=O)- or -OC(=O)- n - a group formed by a part of.

[0056]

[0057] (In the above formula (2') and formula (3), X 2’ and X3 represents a tetravalent organic group, Y 2’ represents a divalent organic group represented by the following formula (O2), and Y3 represents a divalent organic group having a group "-N(D)- (D represents a carbamate-based protective group)" in the molecule, excluding D, and having 6 to 30 carbon atoms. R and Z have the same meanings as in the above formula (1).

[0058]

[0059] In the above formula (O2), m is an integer of 0 to 2, Ar 2’ represents an unsubstituted or substituted benzene ring. Wherein, when m is 0, Ar 2’ represents an unsubstituted benzene ring, and when m is 1 to 2, Ar 2’ Each independently represents an unsubstituted benzene ring, or a benzene ring in which any hydrogen atom on the benzene ring is substituted with a halogen atom or a monovalent organic group (e.g., an alkyl group having 1 to 3 carbon atoms, an alkenyl group having 2 to 3 carbon atoms, an alkynyl group having 2 to 3 carbon atoms, a monovalent organic group having 1 to 3 carbon atoms and having a fluorine atom). 2’ Indicates a single bond or -O-. 2’ , Q 2’ In the case of , each is optionally the same or different. * represents a bonding bond.

[0060] In the above formula (O), examples of the above halogen atom include fluorine atom, chlorine atom, bromine atom and iodine atom. Examples of the above monovalent organic group include: alkyl groups having 1 to 3 carbon atoms, such as methyl, ethyl, propyl and isopropyl; alkenyl groups having 2 to 3 carbon atoms, such as vinyl, propenyl and butenyl; alkynyl groups having 2 to 3 carbon atoms, such as ethynyl, 1-propynyl and 2-propynyl; monovalent organic groups having 1 to 3 carbon atoms, such as fluoromethyl, trifluoromethyl, pentafluoroethyl and pentafluoropropyl, etc., which contain fluorine atoms.

[0061] The divalent organic group represented by the formula (O) is preferably a divalent organic group represented by any one of the following formulae (o-1) to (o-15) from the viewpoint of improving the liquid crystal orientation. In the formula (o-10), m is preferably 2. In the formula (o-14), m is more preferably 0 or 2.

[0062]

[0063] (In formulas (o-14) to (o-15), the two m are independent of each other.)

[0064] As the divalent organic group represented by the formula (O2), from the viewpoint of appropriately obtaining the effects of the present invention, a divalent organic group represented by any one of the following formulae (o2-1) to (o2-12) is preferred.

[0065]

[0066] D of Y3 in the above formula (3) represents a carbamate protecting group, and examples of the carbamate protecting group include Boc and Fmoc. Specific examples of Y3 include divalent organic groups represented by the following formula (Dx).

[0067]

[0068] In the above formula (Dx), Q5 is a single bond, -(CH2) n -(n is 1 to 20), or -(CH2) n Any of the -CH2- in - is replaced by -O-, -Si(CH3)2-, -COO-, -OCO-, -NQ9-, -NQ9-CO-, -CO-NQ9-, -NQ9-CO-NQ 10 -, -NQ9-COO- or -O-COO- substituted groups, Q9 and Q 10 Each independently represents a hydrogen atom or a monovalent organic group.

[0069] Q6 and Q7 each independently represent -H, -NHD, -N(D)2, a group having -NHD, or a group having -N(D)2. When m=0, Q6 has a carbamate protecting group, and when m=1, at least one of Q5, Q6, and Q7 has a carbamate protecting group in the group. In addition, when Q6 and Q7 represent a group having -NHD or a group having -N(D)2, the preferred carbon number of Q6 and Q7 excluding D is 1 to 10, and more preferably 1 to 8.

[0070] As mentioned above Q9 and Q 10 The monovalent organic group may include an alkyl group having 1 to 3 carbon atoms, an alkenyl group having 2 to 3 carbon atoms, an alkynyl group having 2 to 3 carbon atoms, a monovalent organic group having 1 to 3 carbon atoms and having a fluorine atom, Boc or Fmoc. Specific examples of the alkyl group having 1 to 3 carbon atoms, the alkenyl group having 2 to 3 carbon atoms, the alkynyl group having 2 to 3 carbon atoms, and the monovalent organic group having 1 to 3 carbon atoms and having a fluorine atom include the same structures as the monovalent organic group exemplified in the above formula (O).

[0071] Preferred specific examples of Y3 include divalent organic groups represented by any one of the following formulae (Y3-1) to (Y3-9), from the viewpoint of appropriately obtaining the effects of the present invention.

[0072]

[0073] As X in the above formula (2') and formula (3), 2’ , X3, in addition to the tetravalent organic group represented by the following formula (g), may also be a tetravalent organic group represented by any of the following formulas (X-1) to (X-25), a tetravalent organic group derived from an aromatic tetracarboxylic dianhydride, etc. 2’ X3 is more preferably a tetravalent organic group represented by the following formula (g), and further preferably a tetravalent organic group represented by (g) in which R1 and R4 are methyl groups, and R2 and R3 are hydrogen atoms.

[0074]

[0075] (R1 to R4 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 having a fluorine atom, or a phenyl group, and at least one of R1 to R4 represents a group other than a hydrogen atom as defined above.)

[0076]

[0077] Specific examples of the alkyl group having 1 to 6 carbon atoms in R1 to R4 in the above formula (g) include methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, etc. Specific examples of the alkenyl group having 2 to 6 carbon atoms in R1 to R4 include ethenyl, propenyl, butenyl, etc., which may be linear or branched. Specific examples of the alkynyl group having 2 to 6 carbon atoms in R1 to R4 include ethynyl, 1-propynyl, 2-propynyl, 1-butynyl, 2-butynyl, 3-butynyl, etc. Specific examples of the monovalent organic group having 1 to 6 carbon atoms and containing fluorine atoms in R1 to R4 include fluoromethyl, trifluoromethyl, pentafluoroethyl, pentafluoropropyl, etc.

[0078] The aromatic tetracarboxylic dianhydride is an acid dianhydride obtained by intramolecular dehydration of a carboxyl group bonded to an aromatic ring such as a benzene ring or a naphthalene ring. Specific examples include a tetravalent organic group represented by any of the following formulas (Xa-1) to (Xa-2) and a tetravalent organic group represented by any of the following formulas (Xr-1) to (Xr-7).

[0079]

[0080] (x and y are each independently a single bond, an ether group, a carbonyl group, an ester group, an alkanediyl group having 1 to 10 carbon atoms, a 1,4-phenylene group, a sulfonyl group or an amide bond. j and k are 0 or 1.)

[0081]

[0082] The tetravalent organic group represented by the above formula (Xa-1) or (Xa-2) may be a structure represented by any one of the following formulas (Xa-3) to (Xa-19).

[0083]

[0084] The polyimide (A) may be a polyimide having a repeating unit (a4) represented by the following formula (4) in addition to the repeating unit (a1), the repeating unit (a2), the repeating unit (ar), the repeating unit (a2′), and the repeating unit (a3).

[0085]

[0086] In the above formula (4), X4 represents a tetravalent organic group, and Y4 represents a divalent organic group. R and Z have the same meanings as R and Z in the above formula (1). Among them, Y4 represents a structure other than a divalent organic group having a group "-N(D)- (D represents a carbamate-based protective group)" in the molecule, a divalent organic group having 6 to 30 carbon atoms excluding D, and a divalent organic group represented by the above formula (O2). Moreover, when X4 is a tetravalent organic group represented by the above formula (g), and has the same meaning as a tetravalent organic group in which R1 and R4 are methyl groups, and R2 and R3 are hydrogen atoms, Y4 represents a structure other than 2-methyl-1,4-phenylene, a divalent organic group represented by the above formula (2m), and a divalent organic group represented by the above formula (O).

[0087] As specific examples of X4, the above-mentioned X 2’ From the viewpoint of appropriately obtaining the effect of the present invention, X4 is preferably a tetravalent organic group represented by the above formula (g), or a tetravalent organic group represented by any one of the above formulas (X-1) to (X-25), and more preferably a tetravalent organic group represented by the above formula (g).

[0088] Specific examples of the divalent organic group of Y4 include, in addition to the divalent organic groups exemplified in the above formula (O), divalent organic groups derived from diamines described below (divalent organic groups obtained by removing two amino groups from diamines).

[0089] 2,5-dimethyl-1,4-phenylenediamine, 2-fluoro-1,4-phenylenediamine, 2-methoxy-1,4-phenylenediamine, 2,5-dimethoxy-1,4-phenylenediamine, 4,4'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 3,3'-dimethyl-4,4'-diaminodiphenylmethane; diamines having a photo-alignment group such as diamines represented by the following formulas (g-1) to (g-9); diamines having a urea bond such as diamines represented by the following formulas (u-1) to (u-3) (wherein the diamines do not have a carbamate-based protecting group in the molecule); diamines having an amide bond such as diamines represented by the following formulas (u-4) to (u-7) (wherein the diamines do not have a carbamate-based protecting group in the molecule); a nitrogen-containing structure having at least one selected from the group consisting of a nitrogen-containing heterocyclic ring, a secondary amino group, and a tertiary amino group (hereinafter also referred to as a nitrogen-containing structure).Among them, the diamine having a carboxyl group such as 2,4-diaminobenzoic acid, 2,5-diaminobenzoic acid, 3,5-diaminobenzoic acid or a diamine compound represented by the following formula (3b-1) to (3b-4); 4-(2-(methylamino)ethyl)aniline, 4- (2-aminoethyl)aniline, 4,4'-diaminobenzophenone, 1-(4-aminophenyl)-1,3,3-trimethyl-1H-indane-5-amine, 1-(4-aminophenyl)-2,3-dihydro-1,3,3-trimethyl-1H-indane-6-amine; diamines having a photopolymerizable group at the end, such as 2-(2,4-diaminophenoxy)ethyl methacrylate and 2,4-diamino-N,N-diallylaniline; cholesteryloxy-3,5-diaminobenzene, cholesteryloxy-3,5-di Diamines having a steroidal skeleton, such as aminobenzene, cholesteryloxy-2,4-diaminobenzene, 3,5-diaminobenzoic acid cholesteryl ester, 3,5-diaminobenzoic acid cholesteryl ester, 3,5-diaminobenzoic acid lanosteryl ester, and 3,6-bis(4-aminobenzoyloxy)cholestane; diamines represented by the following formulas (V-1) to (V-6); diamines having a siloxane bond, such as 1,3-bis(3-aminopropyl)-tetramethyldisiloxane; diamines having an oxazoline ring bond, such as the following formulas (Ox-1) and (Ox-2); diamines having a radical polymerization initiator function, such as 1-(4-(2,4-diaminophenoxy)ethoxy)phenyl)-2-hydroxy-2-methylacetone, 3,5-diaminobenzoic acid 2-(4-(2-hydroxy-2-methylpropionyl)phenoxy)ethyl ester, 4,4'-diaminobenzophenone, 3,3'-diaminobenzophenone, and the like; and diamines derived from diamines, and divalent organic groups represented by any one of formulas (Y-1) to (Y-167) described in WO2018 / 117239.

[0090]

[0091]

[0092] In the above formula (3b-1), A 1 It 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-, m1 and m2 are each independently 0 to 4, and the total of m1 and m2 is 1 to 4.

[0093] In the above formula (3b-2), m3 and m4 are each independently 1 to 5. In the above formula (3b-3), A 2 represents a linear or branched alkyl group having 1 to 5 carbon atoms, and m5 is 1 to 5. In the above formula (3b-4), A 3 and A 4 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-, and m6 is 1 to 4.

[0094]

[0095] In the above formulas (V-1) to (V-6), X v1 ~X v4 , X p1 ~X p2 Each independently represents -(CH2) a -(a is 1 to 15), -CONH-, -NHCO-, -CON(CH3)-, -NH-, -O-, -CH2O-, -CH2OCO-, -COO-, or -OCO-, X v5 Represents -O-, -CH2O-, -CH2OCO-, -COO-, or -OCO-. X a Represents a single bond, -O-, -NH-, -O-(CH2) m -O-(m is 1 to 6), -C(CH3)2-, -CO-, -(CH2) m -(m is 1 to 6), -SO2-, -O-C(CH3)2-, -CO-(CH2) m -(m is 1 to 6), -NH-(CH2) m -(m is 1 to 6), -SO2-(CH2) m -(m is 1 to 6), -CONH-(CH2) m -(m is 1 to 6), -CONH-(CH2) m -NHCO-(m is 1 to 6), -COO-(CH2) m -OCO-(m is 1 to 6), -CONH-, -NH-(CH2) m -NH-(m represents 1 to 6), or -SO2-(CH2) m -SO2-(m is 1 to 6), R v1 ~R v4, R 1a ~R 1b Each independently represents an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, or an alkoxyalkyl group having 2 to 20 carbon atoms. k may be the same or different.

[0096]

[0097] Examples of the nitrogen-containing heterocyclic ring include pyrrole, imidazole, pyrazole, triazole, pyridine, pyrimidine, pyridazine, pyrazine, indole, benzimidazole, purine, quinoline, isoquinoline, naphthyridine, quinoxaline, phthalazine, triazine, carbazole, acridine, piperidine, piperazine, pyrrolidine, and hexamethyleneimine. Among them, pyridine, pyrimidine, pyrazine, piperidine, piperazine, quinoline, carbazole, or acridine is preferred.

[0098] The secondary amino group and the tertiary amino group which the diamine having a nitrogen atom-containing structure may have are represented by, for example, the following formula (n).

[0099]

[0100] In the above formula (n), R represents a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms. "*1" represents a bond to the hydrocarbon group. Examples of the monovalent hydrocarbon group of R in the above formula (n) include: alkyl groups such as methyl, ethyl, and propyl; cycloalkyl groups such as cyclohexyl; aryl groups such as phenyl and methylphenyl. R is preferably a hydrogen atom or a methyl group.

[0101] Specific examples of the diamine having a structure containing a nitrogen atom include 2,6-diaminopyridine, 3,4-diaminopyridine, 2,4-diaminopyrimidine, 3,6-diaminocarbazole, N-methyl-3,6-diaminocarbazole, N-ethyl-3,6-diaminocarbazole, N-phenyl-3,6-diaminocarbazole, 1,4-bis-(4-aminophenyl)-piperazine, 3,6-diaminoacridine, compounds represented by the following formulas (Dp-1) to (Dp-8), and compounds represented by the following formulas (z-1) to (z-13).

[0102]

[0103]

[0104] When the polyimide (A) contains repeating units other than the repeating units (a1), the repeating units (a2) and the imidized structural units of at least one of these repeating units, it is more preferred that the total of the repeating units (a1), the repeating units (a2) and the imidized structural units of at least one of these repeating units be set to 99 mol% or less of all the repeating units possessed by the polyimide (A), further preferably to 95 mol% or less, and most preferably to 90 mol% or less.

[0105] In the case where the polyimide (A) contains at least any one of a repeating unit (a3) ​​and an imidized structure unit of a repeating unit (a3), from the viewpoint of appropriately obtaining the effect of the present invention, the polyimide (A) more preferably contains the sum of the repeating unit (a3) ​​and the imidized structure of the repeating unit (a3) ​​at 1 to 30 mol % of all the repeating units, and further preferably contains the sum of the repeating unit (a3) ​​and the imidized structure of the repeating unit (a3) ​​at 1 to 25 mol % of all the repeating units.

[0106] When the polyimide (A) contains at least any one of the above-mentioned repeating units (a4) and their imidized structural units, from the viewpoint of appropriately obtaining the effect of the present invention, it is preferably composed of at least any one of the repeating units (a4) and their imidized structural units, in which Y4 is a divalent organic group that does not have a side chain structure with more than 4 carbon atoms.

[0107] Examples of the divalent organic group having no side chain structure having 4 or more carbon atoms include divalent organic groups derived from diamines selected from the group consisting of diamines obtained by removing 2-(2,4-diaminophenoxy)ethyl methacrylate, 2,4-diamino-N,N-diallylaniline, the diamines having a steroid skeleton, the diamines represented by the above formulae (V-1) to (V-6), 1-(4-(2,4-diaminophenoxy)ethoxy)phenyl)-2-hydroxy-2-methylacetone, 3,5-diaminobenzoic acid-2-(4-(2-hydroxy-2-methylpropionyl)phenoxy)ethyl ester, N-phenyl-3,6-diaminocarbazole, and diamines represented by (z-4) and (z-6).

[0108] In the case where the polyimide (A) contains at least any one of the repeating units (a4) and the imidized structural units of the repeating units (a4), from the viewpoint of appropriately obtaining the effect of the present invention, the polyimide (A) more preferably contains the total of the repeating units (a4) and the imidized structures of the repeating units (a4) at 1 to 30 mol % of all the repeating units, and further preferably contains the total of the repeating units (a4) and the imidized structures of the repeating units (a4) at 1 to 25 mol % of all the repeating units.

[0109] From the viewpoint of appropriately obtaining the effects of the present invention, the total amount of repeating units of the tetravalent organic group represented by the above formula (g) in which R1 and R4 of the polyimide (A) are methyl groups and R2 and R3 are hydrogen atoms is more preferably 70 mol% or more of all repeating units of the tetravalent organic group derived from tetracarboxylic dianhydride or a derivative thereof possessed by the polyimide (A), further preferably 80 mol% or more, and most preferably 100 mol%.

[0110] <Polyamic acid (B)>

[0111] The liquid crystal aligning agent of the present invention contains a polyamic acid (B). In addition, the polyamic acid (B) may be composed of one kind or two or more kinds.

[0112] In addition, although the polyamic acid (B) may contain the imidation product which carried out imidization, the content ratio of the imidation product in the polyamic acid (B) is preferably less than 30 mol%, and more preferably less than 10 mol%.

[0113] The polyamic acid (B) has a repeating unit (b1) represented by the above formula (5).

[0114] In addition, the repeating unit which comprises polyamic acid (B) may be one type or two or more types.

[0115] In the above formula (5), X5 is a tetravalent organic group, Y5 is a divalent organic group, and Z has the same meaning as Z in the above formula (1).

[0116] Examples of the tetravalent organic group in X5 include a tetravalent organic group derived from acyclic aliphatic tetracarboxylic dianhydride, a tetravalent organic group derived from alicyclic tetracarboxylic dianhydride, and a tetravalent organic group derived from aromatic tetracarboxylic dianhydride.

[0117] Here, alicyclic tetracarboxylic dianhydride is an acid dianhydride obtained by intramolecular dehydration of four carboxyl groups including at least one carboxyl group bonded to an alicyclic structure. Among them, none of these four carboxyl groups is bonded to an aromatic ring. In addition, it is not necessary to be composed only of an alicyclic structure, and a part of it may also have a chain hydrocarbon structure or an aromatic ring structure.

[0118] Acyclic aliphatic tetracarboxylic dianhydride is an acid dianhydride obtained by intramolecular dehydration of four carboxyl groups bonded to a chain hydrocarbon structure. However, it is not necessary to be composed of only a chain hydrocarbon structure, and may have an alicyclic structure or an aromatic ring structure in part.

[0119] The aromatic tetracarboxylic dianhydride is not particularly limited as long as it is an acid dianhydride obtained by intramolecular dehydration of four carboxyl groups including at least one carboxyl group bonded to an aromatic ring.

[0120] From the viewpoint of appropriately obtaining the effect of the present invention, the above-mentioned non-cyclic aliphatic or alicyclic tetracarboxylic dianhydride is preferably a tetracarboxylic dianhydride having at least one partial structure selected from the group consisting of a cyclobutane ring structure, a cyclopentane ring structure, and a cyclohexane ring structure from the viewpoint of appropriately obtaining the effect of the present invention. In addition, from the viewpoint of appropriately obtaining the effect of the present invention, the above-mentioned aromatic tetracarboxylic dianhydride is preferably a tetracarboxylic dianhydride having a benzene ring.

[0121] Under the viewpoint of suitably obtaining the effect of the present invention, above-mentioned X5 is more preferably a tetravalent organic group with at least one partial structure selected from the group consisting of a benzene ring, a cyclobutane ring structure, a cyclopentane ring structure and a cyclohexane ring structure. As a more preferred specific example of X5, the tetravalent organic group shown in the above-mentioned X4 can be enumerated.

[0122] More preferably, X5 is a tetravalent organic group represented by the above formula (g), a tetravalent organic group represented by any of the above formulas (X-1) to (X-25), a tetravalent organic group represented by the above formulas (Xa-1) to (Xa-2), or a tetravalent organic group represented by the above formulas (Xr-1) to (Xr-7) (these are also collectively referred to as specific tetravalent organic groups).

[0123] From the viewpoint of appropriately obtaining the effect of the present invention, the polyamic acid (B) preferably contains a repeating unit in which X5 is the above-mentioned specific tetravalent organic group at 5 mol % or more of all repeating units contained in the polyamic acid (B), and more preferably contains a repeating unit in which X5 is the above-mentioned specific tetravalent organic group at 10 mol % or more of all repeating units contained in the polyamic acid (B).

[0124] As the divalent organic group in the above Y5, the divalent organic groups exemplified in the above Y4 can be cited. From the viewpoint of less afterimages derived from residual DC, the polyamic acid (B) is preferably a polymer containing the following repeating units, wherein Y5 is a repeating unit derived from the above diamine having a urea bond, the above diamine having an amide bond, the above diamine having a structure containing a nitrogen atom, 2,4-diaminophenol, 3,5-diaminophenol, 3,5-diaminobenzyl alcohol, 2,4-diaminobenzyl alcohol, 4,6-diaminoresorcinol, the above diamine having a carboxyl group, 4,4'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 3,3'-dimethyl-4,4'-diaminodiphenylmethane, p-phenylenediamine or m-phenylenediamine (these are also collectively referred to as specific divalent organic groups).

[0125] From the viewpoint of improving transmittance, the polyamic acid (B) more preferably has two or more repeating units represented by the above formula (5), including repeating units having Y5 as a divalent organic group derived from the above diamine having a urea bond, the above diamine having an amide bond, or the above diamine having a structure containing a nitrogen atom, and repeating units having Y5 as a divalent organic group derived from diamines other than these.

[0126] From the viewpoint of less afterimage originating from residual DC, the polyamic acid (B) preferably contains a repeating unit in which Y5 is the above-mentioned specific divalent organic group at 1 mol % or more of all repeating units contained in the polyamic acid (B), preferably, more preferably, contains the repeating unit at 5 mol % or more of all repeating units contained in the polyamic acid (B), further preferably, contains the repeating unit at 10 mol % or more of all repeating units contained in the polyamic acid (B), and particularly preferably contains the repeating unit at 20 mol % or more of all repeating units contained in the polyamic acid (B).

[0127] From the viewpoint of reducing image sticking due to residual DC, the content ratio of polyimide (A) to polyamic acid (B) (mass ratio of polyimide (A) / polyamic acid (B)) is preferably 10 / 90 to 90 / 10, more preferably 20 / 80 to 90 / 10, and further preferably 20 / 80 to 80 / 20.

[0128] <Method for producing polyimide (A) and polyamic acid (B)>

[0129] The polyamic acid ester, the polyamic acid, and the polyimide or the polyamic acid (B) which are the precursors of the polyimide (A) of the present invention can be synthesized by a known method as described in, for example, WO2013 / 157586.

[0130] Specifically, by making diamine component and tetracarboxylic acid derivative component (polycondensation) reaction in solvent to synthesize.As the above-mentioned tetracarboxylic acid derivative component, tetracarboxylic dianhydride or its derivative (tetracarboxylic acid dihalide, tetracarboxylic acid diester or tetracarboxylic acid diester dihalide) can be listed.In the case of including amic acid structure in a part of polyimide (A), for example, by making tetracarboxylic dianhydride component and diamine component react, obtain the polymer (polyamic acid) with amic acid structure.As solvent, as long as dissolving the generated polymer is not particularly limited.

[0131] The diamine component and the tetracarboxylic acid derivative component of the polyimide precursor for obtaining the polyimide (A) correspond to the repeating units represented by the above-mentioned formula (1), formula (2), formula (Ar), formula (2'), formula (3) and formula (4) respectively, and are selected and used in a manner that can obtain the structure of the above-mentioned repeating units.

[0132] For example, in the case of a repeating unit represented by the formula (1) possessed by a polyimide (A), a diamine having a structure of -N(Z)-Y1-N(Z)- (Y1 represents 2-methyl-1,4-phenylene. The definition of Z has the same meaning as described above) is used as a diamine component, and a tetracarboxylic acid derivative having a structure of the following formula (mt) is used as a tetracarboxylic acid derivative component.

[0133]

[0134] The diamine component and the tetracarboxylic acid derivative component used in the case of obtaining a polyimide precursor having repeating units represented by the formula (2), formula (ar), formula (2'), formula (3) and formula (4) possessed by the polyimide (A) are selected and used according to the diamine and the tetracarboxylic acid derivative used in the case of obtaining a polyimide precursor having repeating units represented by the above-mentioned formula (1).

[0135] In addition, the diamine component and the tetracarboxylic acid derivative component used to obtain the polyamic acid (B) are selected and used in a manner that the structure of the repeating unit shown in the above formula (5) possessed by the polyamic acid (B) can be obtained. That is, as the diamine component, a diamine having a structure of -N(Z)-Y5-N(Z)- (the definitions of Y5 and Z are the same as above) is used, and as the tetracarboxylic acid derivative component, a tetracarboxylic acid derivative having a structure of X5 (the definition of X5 is the same as above) is used.

[0136] Specific examples of the solvent used when reacting the diamine component with the tetracarboxylic acid derivative component include N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, γ-butyrolactone, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, and 1,3-dimethyl-2-imidazolidinone. In addition, when the polymer has high solubility in a solvent, methyl ethyl ketone, cyclohexanone, cyclopentanone, 4-hydroxy-4-methyl-2-pentanone, or solvents represented by the following formulas [D-1] to [D-3] can be used.

[0137]

[0138] (In formula [D-1], D 1 represents an alkyl group having 1 to 3 carbon atoms, wherein in the formula [D-2], D 2 represents an alkyl group having 1 to 3 carbon atoms, wherein D 3 represents an alkyl group having 1 to 4 carbon atoms).

[0139] These solvents may be used alone or in combination. Furthermore, even a solvent that does not dissolve the polymer may be used by mixing with the above solvents as long as the generated polymer does not precipitate.

[0140] When the diamine component and the tetracarboxylic acid derivative component are reacted in a solvent, the reaction may be performed at any concentration, preferably 1 to 50% by mass, more preferably 5 to 30% by mass. The reaction may be performed at a high concentration in the initial stage and then the solvent may be added.

[0141] In the reaction, the ratio of the total molar number of the diamine component to the total molar number of the tetracarboxylic acid derivative component (total molar number of the tetracarboxylic acid derivative component / total molar number of the diamine component) is preferably 0.8 to 1.2. As in a normal polycondensation reaction, the closer this molar ratio is to 1.0, the greater the molecular weight of the polyimide (A) and polyamic acid (B) produced.

[0142] Polyamic acid ester can be obtained by, for example, a known method such as [I] a method of reacting the polyamic acid obtained by the above method with an esterifying agent; [II] a method of reacting a tetracarboxylic acid diester with a diamine; or [III] a method of reacting a tetracarboxylic acid diester dihalide with a diamine.

[0143] Examples of the method for obtaining a polyimide include thermal imidization in which a solution containing a polyimide precursor such as a polyamic acid or a polyamic acid ester obtained in the above reaction is heated as it is, and catalytic imidization in which a catalyst is added to the above solution.

[0144] The polyimide (A) is a polyimide precursor in which a part or all of the repeating units are ring-closed. The imidization rate of the polyimide (A) is more preferably 30% or more, more preferably 50% or more, and most preferably 60% or more. In addition, the imidization rate of the polyimide (A) is more preferably 95% or less, and more preferably 90% or less.

[0145] <Polymer solution viscosity / molecular weight>

[0146] For the polyimide (A) and polyamic acid (B) of the present invention, when the solution is made into a concentration of 10 to 15% by mass, for example, from the viewpoint of workability, it is preferably a polymer having a solution viscosity of 10 to 1000 mPa·s, but it is not particularly limited. It should be noted that the solution viscosity (mPa·s) of the above polymer is a value measured at 25°C using an E-type rotational viscometer for a polymer solution having a concentration of 10 to 15% by mass prepared using a good solvent for the polymer (e.g., γ-butyrolactone, N-methyl-2-pyrrolidone, etc.).

[0147] The weight average molecular weight (Mw) of the polyamic acid, polyamic acid ester and polyimide measured by gel permeation chromatography (GPC) in terms of polystyrene is preferably 1000 to 500000, more preferably 2000 to 300000. In addition, the molecular weight distribution (Mw / Mn) represented by the ratio of Mw to the number average molecular weight (Mn) in terms of polystyrene measured by GPC is preferably 15 or less, more preferably 10 or less. Within this molecular weight range, good orientation and stability of the liquid crystal display element can be ensured.

[0148] <Capping agent>

[0149] When synthesizing the polyimide (A) and the polyamic acid (B) in the present invention, an appropriate end-capping agent may be used together with the tetracarboxylic acid derivative component and the diamine component as described above to prepare an end-capped polymer. The end-capped polymer has the effect of increasing the film hardness of the liquid crystal alignment film obtained from the coating film and improving the adhesion characteristics of the sealant and the liquid crystal alignment film.

[0150] As examples of the ends of the polyimide (A) and the polyamic acid (B) in the present invention, amino groups, carboxyl groups, anhydride groups or their derivatives can be listed. Amino groups, carboxyl groups, anhydride groups, isocyanate groups can be obtained by a common condensation reaction, or by blocking the ends using the following blocking agents, for example, they can be obtained in the same manner using the following blocking agents.

[0151] Examples of the end-capping agent include: acid monoanhydrides such as acetic anhydride, maleic anhydride, nadic 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, and 4-ethynylphthalic anhydride; dicarbonic acid diester compounds such as di-tert-butyl dicarbonate and diallyl dicarbonate; chlorocarbonyl compounds such as acryloyl chloride, methacryloyl chloride, and nicotinoyl chloride; aniline, 2-butyl dicarbonate, and 2-butyl dicarbonate; 4-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, n-octylamine and other monoamine compounds; isocyanate compounds having unsaturated bonds such as ethyl isocyanate, phenyl isocyanate, naphthyl isocyanate, 2-acryloyloxyethyl isocyanate and 2-methacryloyloxyethyl isocyanate; isothiocyanate compounds such as ethyl isothiocyanate and allyl isothiocyanate, etc.

[0152] The amount of the terminal blocking agent used is preferably 0.01 to 20 parts by mole, more preferably 0.01 to 10 parts by mole, based on 100 parts by mole of the total of the diamine components used.

[0153] <Liquid crystal alignment agent>

[0154] The liquid crystal alignment agent of the present invention contains polyimide (A) and polyamic acid (B). In addition to polyimide (A) and polyamic acid (B), the liquid crystal alignment agent of the present invention may also contain other polymers. If specific examples of other polymers are listed, there can be listed a polymer selected from the group consisting of polyimides other than polyimide (A), polyimide precursors other than polyamic acid (B), polysiloxanes, polyesters, polyamides, polyureas, polyurethanes, polyorganosiloxanes, cellulose derivatives, polyacetals, polystyrene derivatives, poly(styrene-maleic anhydride) copolymers, poly(isobutylene-maleic anhydride) copolymers, poly(vinyl ether-maleic anhydride) copolymers, poly(styrene-phenylmaleimide) derivatives, and poly(meth)acrylates.

[0155] As specific examples of poly(styrene-maleic anhydride) copolymers, SMA1000, 2000, 3000 (manufactured by Cray Valley), GSM301 (manufactured by Gifu Shellac Manufacturing Co., Ltd.), etc. can be cited. As specific examples of poly(isobutylene-maleic anhydride) copolymers, Isobam-600 (manufactured by KURARAY) can be cited. As specific examples of poly(vinyl ether-maleic anhydride) copolymers, Gantrez AN-139 (methyl vinyl ether maleic anhydride resin, manufactured by Ashland) can be cited. Other polymers can be used alone or in combination of two or more. The content ratio of other polymers is preferably 90 parts by mass or less, more preferably 10 to 90 parts by mass, and further preferably 20 to 80 parts by mass relative to the total of 100 parts by mass of the polymers contained in the liquid crystal alignment agent.

[0156] The liquid crystal alignment agent is used to make a liquid crystal alignment film, and from the viewpoint of forming a uniform film, a coating liquid is used. In the liquid crystal alignment agent of the present invention, a coating liquid containing the above-mentioned polymer component and an organic solvent is also preferred. At this time, the concentration of the polymer in the liquid crystal alignment agent can be appropriately changed according to the setting of the thickness of the coating film to be formed. From the perspective of forming a uniform and defect-free coating film, the concentration of the polymer in the liquid crystal alignment agent is preferably 1% by mass or more, and from the perspective of the storage stability of the solution, it is preferably 10% by mass or less. The concentration of the polymer is particularly preferably 2 to 8% by mass.

[0157] The organic solvent contained in the liquid crystal alignment agent is not particularly limited as long as it is a solvent that uniformly dissolves the polymer component. Specific examples thereof include: N, N-dimethylformamide, N, N-dimethylacetamide, N, N-dimethyllactamide, N, N-dimethylpropionamide, tetramethylurea, N, N-diethylformamide, 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-dimethyl Propionamide, 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, N-cyclohexyl-2-pyrrolidone (these are also collectively referred to as "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. The content of the good solvent is preferably 20 to 99% by mass of the total solvent contained in the liquid crystal aligning agent, more preferably 20 to 90% by mass, and particularly preferably 30 to 80% by mass.

[0158] In addition, the organic solvent contained in the liquid crystal aligning agent preferably uses a mixed solvent of a solvent (also referred to as a poor solvent) that improves the coating property and surface smoothness of the coating film when the liquid crystal aligning agent is applied in addition to the above-mentioned solvent. The content of the poor solvent is preferably 1 to 80% by mass of the entire solvent contained in the liquid crystal aligning agent, more preferably 10 to 80% by mass of the entire solvent contained in the liquid crystal aligning agent, and particularly preferably 20 to 70% by mass of the entire solvent contained in the liquid crystal aligning agent. The type and content of the poor solvent are appropriately selected according to the coating device, coating conditions, coating environment, etc. of the liquid crystal aligning agent.

[0159] Specific examples of the poor solvent are described below, but the poor solvent is not limited thereto.

[0160] Examples thereof include 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, ethylene glycol monoisopentyl ether, ethylene glycol monohexyl ether, propylene glycol monomethyl ether, propylene glycol monobutyl ether, 1-(2-butoxyethoxy)-2-propanol, 2-(2-butoxyethoxy)-2-propanol, 1-(2-(2-ethoxyethoxy)ethyl)acetate, diethylene glycol acetate, propylene glycol diacetate, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol dimethyl ether, ethylene glycol monobutyl ether acetate, diethylene glycol monopropyl ether, 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, cyclohexyl acetate, 4-methyl-2-pentyl 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, diisobutyl ketone (2,6-dimethyl-4-heptanone), and the like.

[0161] Among them, the poor solvent is preferably diisobutylcarbinol, 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.

[0162] Preferred combinations of good solvents and poor solvents include N-methyl-2-pyrrolidone and ethylene glycol monobutyl ether, N-methyl-2-pyrrolidone and γ-butyrolactone and ethylene glycol monobutyl ether, N-methyl-2-pyrrolidone and 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 3-ethoxypropionate and dipropylene glycol monomethyl Ether, N-ethyl-2-pyrrolidone and ethyl 3-ethoxypropionate and propylene glycol monobutyl ether, N-methyl-2-pyrrolidone and ethyl 3-ethoxypropionate and diethylene glycol monopropyl ether, N-ethyl-2-pyrrolidone and ethyl 3-ethoxypropionate and diethylene glycol monopropyl ether, N-methyl-2-pyrrolidone and ethylene 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-ethyl-2-pyrrolidone and diethylene glycol monoethyl ether and butyl cellosolve acetate, N-methyl-2-pyrrolidone and diethylene glycol monomethyl ether and butyl cellosolve acetate, N,N-dimethyl lactamide and diethylene glycol diethyl ether, N-methyl-2-pyrrolidone and γ-butyrolactone and 4-hydroxy-4-methyl-2-pentanone and diethylene glycol diethyl ether, N-ethyl-2-pyrrolidone and N-methyl-2-pyrrolidone and 4-hydroxy-4-methyl-2-pentanone, N-ethyl-2-pyrrolidone and 4-hydroxy-4-methyl-2-pentanone and propylene glycol monobutyl ether, N-methyl-2-pyrrolidone and 4-hydroxy-4-methyl-2-pentanone and diisobutyl ketone, N-methyl-2-pyrrolidone and 4-hydroxy-4-methyl-2-pentanone and dipropylene glycol monomethyl ether, N-methyl-2-pyrrolidone and 4-Hydroxy-4-methyl-2-pentanone and propylene glycol monobutyl ether, N-methyl-2-pyrrolidone and 4-hydroxy-4-methyl-2-pentanone and propylene glycol diacetate, N-ethyl-2-pyrrolidone and 4-hydroxy-4-methyl-2-pentanone and dipropylene glycol dimethyl ether, γ-butyrolactone and 4-hydroxy-4-methyl-2-pentanone and diisobutyl ketone, γ-butyrolactone and 4-hydroxy-4-methyl-2-pentanone and propylene glycol diacetate, N-methyl-2-pyrrolidone and γ-butyrolactone and propylene glycol monobutyl ether and diisobutyl ketone, N-methyl-2-pyrrolidone and γ-butyrolactone and propylene glycol monobutyl ether and diisopropyl ether, N-methyl N-methyl-2-pyrrolidone and γ-butyrolactone and propylene glycol monobutyl ether and diisobutyl carbinol, N-methyl-2-pyrrolidone and γ-butyrolactone and dipropylene glycol dimethyl ether, N-methyl-2-pyrrolidone and propylene glycol monobutyl ether and dipropylene glycol dimethyl ether, N-ethyl-2-pyrrolidone and propylene glycol monobutyl ether and dipropylene glycol monomethyl ether, N-ethyl-2-pyrrolidone and diethylene glycol diethyl ether and dipropylene glycol monomethyl ether, N-ethyl-2-pyrrolidone and propylene glycol monobutyl ether and propylene glycol diacetate, N-ethyl-2-pyrrolidone and propylene glycol monobutyl ether and diisobutyl ketone, N-ethyl-2-pyrrolidone and γ-butyrolactone and diisobutyl Ketone, N-ethyl-2-pyrrolidone and N, N-dimethyl lactamide and diisobutyl ketone, N-methyl-2-pyrrolidone and ethylene glycol monobutyl ether and ethylene glycol monobutyl ether acetate, γ-butyrolactone and ethylene glycol monobutyl ether acetate and dipropylene glycol dimethyl ether, N-ethyl-2-pyrrolidone and ethylene glycol monobutyl ether acetate and propylene glycol dimethyl ether, N-methyl-2-pyrrolidone and 4-methyl-2-pentyl acetate and ethylene glycol monobutyl ether, N-ethyl-2-pyrrolidone and cyclohexyl acetate and diacetone alcohol cyclohexanone and propylene glycol monomethyl ether, cyclopentanone and propylene glycol monomethyl ether, N-methyl-2-pyrrolidone and cyclohexanone and propylene glycol monomethyl ether, etc. ,

[0163] The liquid crystal aligning agent of the present invention may be supplemented with components other than the polymer component and the organic solvent (hereinafter also referred to as additive components). Such additive components include: a close adhesion aid for improving the close adhesion between the liquid crystal aligning film and the substrate, the close adhesion between the liquid crystal aligning film and the sealant, a compound for improving the strength of the liquid crystal aligning film (hereinafter also referred to as a cross-linking compound), a compound for promoting imidization, a dielectric for adjusting the dielectric constant and resistance of the liquid crystal aligning film, a conductive substance, etc.

[0164] As the cross-linking compound, from the viewpoint of appropriately obtaining the effect of the present invention, at least one compound selected from the group consisting of a compound having the following group and a compound represented by the following formula (e) can be cited, wherein the group is selected from the group consisting of an oxirane group, an oxetane group, a protected isocyanate group, a protected isothiocyanate group, a group containing an oxazoline ring structure, a group containing a Michaelis acid structure, a cyclocarbonate group, and at least one group (hereinafter also referred to as a cross-linking group) represented by the following formula (d). It is more preferred to have two or more of the above cross-linking groups and the group "-CH2-OR" in the following formula (e) in the molecule.

[0165]

[0166] In the above formula (d), R2 and R3 are each independently a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or "*-CH2-OH". In the above formula (e), A represents an (m+n)-valent organic group having an aromatic ring, R and R' are each independently a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, m is 1 to 6, and n is 0 to 4. Any hydrogen atom of the above aromatic ring may be optionally substituted by 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, or a fluoroalkoxy group having 1 to 10 carbon atoms. * represents a bonding bond.

[0167] Specific examples of compounds having an oxirane group include compounds described in paragraph 0037 of Japanese Patent Application Laid-Open No. 10-338880 and compounds having a triazine ring in the skeleton described in WO2017 / 170483. Among them, compounds containing nitrogen atoms such as N,N,N',N'-tetracyclyl-m-xylene diamine, 1,3-bis(N,N-dicyclylaminomethyl)cyclohexane, N,N,N',N'-tetracyclyl-4,4'-diaminodiphenylmethane, N,N,N',N'-tetracyclyl-p-phenylenediamine, and compounds represented by the following formulas (r-1) to (r-3) may be mentioned.

[0168]

[0169] Specific examples of the compound having an oxetane group include compounds having two or more oxetane groups described in paragraphs 0170 to 0175 of WO2011 / 132751.

[0170] Specific examples of the compound having a protected isocyanate group include compounds having two or more protected isocyanate groups described in paragraphs 0046 to 0047 of JP-A-2014-224978, compounds having three or more protected isocyanate groups described in paragraphs 0119 to 0120 of WO2015 / 141598, and the like, which may be compounds represented by the following formulas (bi-1) to (bi-3).

[0171]

[0172] Specific examples of the compound having a protected isothiocyanate group include compounds having two or more protected isothiocyanate groups described in JP-A-2016-200798.

[0173] Specific examples of the compound having a group containing an oxazoline ring structure include compounds containing two or more oxazoline ring structures described in paragraph 0115 of JP-A-2007-286597.

[0174] Specific examples of the compound having a group containing a Michaelis acid structure include compounds having two or more Michaelis acid structures described in WO2012 / 091088.

[0175] Specific examples of the compound having a cyclic carbonate group include compounds described in WO2011 / 155577.

[0176] Examples of the alkyl group having 1 to 3 carbon atoms in R2 and R3 of the group represented by the above formula (d) include methyl, ethyl, propyl and isopropyl.

[0177] Specific examples of the compound having a group represented by the above formula (d) include compounds having two or more groups represented by the above formula (d) described in WO2015 / 072554, paragraph 0058 of JP-A-2016-118753, and compounds described in JP-A-2016-200798. The compounds may be compounds represented by the following formulas (hd-1) to (hd-8).

[0178]

[0179] Examples of the (m+n)-valent organic group having an aromatic ring in A of the above formula (e) include an (m+n)-valent aromatic hydrocarbon group having 6 to 30 carbon atoms, an (m+n)-valent organic group formed by directly or via a linking group bonding an aromatic hydrocarbon group having 6 to 30 carbon atoms, and an (m+n)-valent group having an aromatic heterocyclic ring. Examples of the above aromatic hydrocarbon group include benzene and naphthalene. Examples of the aromatic heterocyclic ring include an aromatic heterocyclic ring represented by a pyridine ring within the structures exemplified in the above nitrogen-containing heterocyclic ring. Examples of the above linking group include an alkylene group having 1 to 10 carbon atoms, -NR- (R is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms), or a group obtained by removing one hydrogen atom from the above alkylene group, a divalent or trivalent cyclohexane ring, and the like. It should be noted that any hydrogen atom of the above alkylene group may be substituted with an organic group such as an alkyl group having 1 to 6 carbon atoms, a fluorine atom, or a trifluoromethyl group. Examples of the alkyl group having 1 to 5 carbon atoms in R and R' in the above formula (e) include specific examples of the alkyl group exemplified in R1 to R4 in the above formula (g).

[0180] Specific examples of the formula (e) include compounds described in WO2010 / 074269 and compounds represented by any one of the following formulae (e-1) to (e-10).

[0181]

[0182] The compounds exemplified above are examples of crosslinking compounds, but are not limited thereto. For example, compounds disclosed in paragraphs 0105 on page 53 to 0116 on page 55 of WO2015 / 060357 may be cited. In addition, two or more crosslinking compounds may be used in combination.

[0183] The content of the crosslinkable compound in the liquid crystal aligning agent of the present invention is preferably 0.5 to 20 parts by mass, more preferably 1 to 15 parts by mass, based on 100 parts by mass of the polymer component contained in the liquid crystal aligning agent, from the viewpoint of appropriately obtaining the effects of the present invention.

[0184] Examples of the adhesion aid include 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyldiethoxymethylsilane, 2-aminopropyltrimethoxysilane, 2-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, 3-ureidopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-cyclohexyl-3-aminopropyltrimethoxysilane, Silane coupling agents include 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, p-phenylenetrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, tris-[3-(trimethoxysilyl)propyl]isocyanurate, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, and 3-isocyanatepropyltriethoxysilane.

[0185] When using a silane coupling agent, from a viewpoint of appropriately obtaining the effect of the present invention, the amount is preferably 0.1-30 parts by mass, more preferably 0.1-20 parts by mass, based on 100 parts by mass of the polymer component contained in the liquid crystal aligning agent.

[0186] As the above-mentioned compound for promoting imidization, it is preferred to have a compound having a basic part (for example, a primary amino group, an aliphatic heterocycle (for example, a pyrrolidine skeleton), an aromatic heterocycle (for example, an imidazole ring, an indole ring), or a guanidine group, etc.) (excluding the above-mentioned cross-linking compound and a close-fitting aid), or a compound that generates the above-mentioned basic part when fired. More preferred are compounds that generate the above-mentioned basic part when fired. If specific examples are listed, the compounds represented by the following formulas (B-1) to (B-17) can be listed. The content of the compound for promoting imidization is more preferably 0.5 to 30 parts by mass, and further preferably 1 to 20 parts by mass, relative to 100 parts by mass of the polymer component contained in the liquid crystal aligning agent.

[0187]

[0188] (D represents an organic group that is released by heating, and is preferably either Boc or Fmoc. When there are a plurality of Ds, the plurality of Ds may be the same as or different from each other.)

[0189] The solid content concentration in the liquid crystal aligning agent of the present invention (the ratio of the total mass of the components other than the solvent of the liquid crystal aligning agent to the total mass of the liquid crystal aligning agent) can be appropriately selected in consideration of viscosity, volatility, etc., but is preferably in the range of 1 to 10 mass %.

[0190] The range of particularly preferred solid content concentration varies depending on the method used when applying the liquid crystal alignment agent to the substrate. As described in step (1) described later, as a method for applying the liquid crystal alignment agent to the substrate, for example, a roll coater method, a spin coating method, a printing method, an inkjet method, etc. can be cited. When using a roll coater method, the solid content concentration is particularly preferably in the range of 4 to 10% by mass. When using a spin coating method, the solid content concentration is particularly preferably in the range of 1.5 to 4.5% by mass. When using a printing method, it is particularly preferred to set the solid content concentration to a range of 3 to 9% by mass, thereby setting the solution viscosity to a range of 12 to 50 mPa·s. When using an inkjet method, it is particularly preferred to set the solid content concentration to a range of 1 to 5% by mass, thereby setting the solution viscosity to a range of 3 to 15 mPa·s. The temperature when preparing the liquid crystal alignment agent is preferably 10 to 50°C, and more preferably 20 to 30°C.

[0191] <Liquid crystal alignment film>

[0192] The liquid crystal alignment film of the present invention is obtained by the above-mentioned liquid crystal alignment agent. The liquid crystal alignment film of the present invention can be used for a liquid crystal alignment film of a horizontal orientation type or a vertical orientation type (VA type), wherein it is a liquid crystal alignment film suitable for a liquid crystal display element of a horizontal orientation type such as an IPS driving mode or an FFS driving mode. In addition, it is more preferably used for a liquid crystal alignment film for a photo-alignment treatment method. In addition, it can be effectively applied to various technical uses, for example, it can also be applied to liquid crystal alignment films other than the above-mentioned uses (liquid crystal alignment films for phase difference films, scanning antennas, liquid crystal alignment films for liquid crystal array antennas, or liquid crystal alignment films for liquid crystal dimming elements of a transmission scattering type), or other uses, for example, protective films (for example, protective films for color filters), spacer films, interlayer insulating films, anti-reflective films, wiring coating films, antistatic films, motor insulating films (gate insulating films for flexible displays), etc.

[0193] The liquid crystal aligning film of the present invention can be produced by, for example, a method including the following steps (1) to (3), preferably a method including the steps (1) to (4).

[0194] <Step (1): Step of applying a liquid crystal aligning agent onto a substrate>

[0195] 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 a roller coater method, a spin coating method, a printing method, an inkjet method, etc. Here, as a substrate, as long as it is a substrate with high transparency, it is not particularly limited, and a plastic substrate such as an acrylic substrate, a polycarbonate substrate, etc. can also be used together with a glass substrate, a silicon nitride substrate, etc. In addition, in a reflective liquid crystal display element, if it is only a single-sided substrate, an opaque object such as a silicon wafer can also be used, and the electrode in this case can also use a material that reflects light such as aluminum. In addition, in the case of manufacturing a liquid crystal display element of an IPS drive mode or an FFS drive mode, a substrate provided with an electrode composed of a transparent conductive film or a metal film patterned into a comb-shaped pattern and an opposing substrate without an electrode are used.

[0196] As a method of applying a liquid crystal aligning agent to a substrate to form a film, screen printing, offset printing, flexographic printing, an inkjet method, or a spray method can be mentioned. Among them, a method of applying and forming a film by an inkjet method can be preferably used.

[0197] <Step (2): Step of calcining the applied liquid crystal aligning agent>

[0198] Step (2) is a step of firing the liquid crystal aligning agent applied to the substrate to form a film. After the liquid crystal aligning agent is applied to the substrate, the solvent can be evaporated by a heating unit such as a heating 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 firing steps after applying the liquid crystal aligning agent of the present invention can be selected at any temperature and time, and can be performed multiple times. As the firing temperature, for example, it can be carried out at 40 to 180°C. From the viewpoint of shortening the process, it can be carried out at 40 to 150°C. There is no particular limitation on the firing time, and 1 to 10 minutes can be listed, and 1 to 5 minutes is preferably listed. In the case of thermal imidization of polyamic acid or polyamic acid ester, after the above-mentioned firing step, for example, a firing step can be performed at a temperature range of 150 to 300°C, preferably 150 to 250°C. There is no particular limitation on the firing time, and 5 to 40 minutes can be listed, and a firing time of 5 to 30 minutes is preferably listed.

[0199] If the film-like material after firing is too thin, the reliability of the liquid crystal display element may be reduced. Therefore, the thickness is preferably 5 to 300 nm, and more preferably 10 to 200 nm.

[0200] <Step (3): Step of orienting the film obtained in step (2)>

[0201] Step (3) is a step of orienting the film obtained in step (2) as needed. That is, in a horizontally oriented liquid crystal display element such as an IPS drive mode or an FFS drive mode, the coating is treated to impart an orientation ability. On the other hand, in a vertically oriented liquid crystal display element such as a VA mode or a PSA mode, the formed coating can be kept in this state and used as a liquid crystal alignment film, or the coating can be treated to impart an orientation ability. As an orientation treatment method for a liquid crystal alignment film, a friction treatment method and a photo-orientation treatment method can be listed, and a photo-orientation treatment method is more preferred. As a photo-orientation treatment method, the following method can be listed: irradiating the surface of the above-mentioned film-like object with radiation (more preferably radiation deflected in a fixed direction), preferably heating at a temperature of 150 to 250°C according to the circumstances, imparting liquid crystal orientation (also referred to as liquid crystal orientation ability). As radiation, ultraviolet rays or visible light having a wavelength of 100 to 800 nm can be used. Among them, ultraviolet rays having a wavelength of 100 to 400 nm are preferred, and ultraviolet rays having a wavelength of 200 to 400 nm are more preferred.

[0202] The radiation dose is more preferably 100 to 450 mJ / cm 2 , more preferably 100 to 400 mJ / cm 2 , particularly preferably 100 to 350 mJ / cm 2 .

[0203] Furthermore, when irradiating with radiation, in order to improve the liquid crystal orientation, the radiation may be irradiated while heating the substrate having the film-like material at 50 to 250° C. The liquid crystal alignment film thus produced can stably align liquid crystal molecules in a fixed direction.

[0204] The liquid crystal aligning film obtained by the above-mentioned method may be further subjected to a step of contact treatment using a solvent.

[0205] The solvent used for the above-mentioned contact treatment is not particularly limited as long as it is a solvent that dissolves the decomposition product generated by the film due to the irradiation of radiation. As specific examples, water, methanol, ethanol, 2-propanol, acetone, methyl ethyl ketone, 1-methoxy-2-propanol, 1-methoxy-2-propanol acetate, butyl cellosolve, ethyl lactate, methyl lactate, diacetone alcohol, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, propyl acetate, butyl acetate, cyclohexyl acetate, etc. Among them, water, 2-propanol, 1-methoxy-2-propanol or ethyl lactate are preferred from the perspective of versatility and safety of the solvent. Water, 1-methoxy-2-propanol or ethyl lactate is more preferred. The solvent may be one or a combination of two or more.

[0206] The liquid crystal alignment film of the present invention can also be produced by performing the following step (4) after the above step (3). More preferably, step (4) is performed on either the film subjected to the alignment treatment in step (3) or the treated film subjected to the above contact treatment with a solvent.

[0207] <Step (4): Step of performing a heating treatment>

[0208] The coating film irradiated with the radiation may be subjected to a heat treatment. The temperature of the heat treatment is preferably 50 to 300° C., more preferably 120 to 250° C. The heat treatment time is preferably 1 to 30 minutes.

[0209] <Liquid crystal display device>

[0210] The liquid crystal display element of the present invention includes the liquid crystal alignment film of the present invention and is produced as follows: Two substrates on which the liquid crystal alignment films obtained as described above are formed are prepared, and liquid crystal is arranged between the two substrates disposed opposite to each other. Specifically, the following two methods can be cited.

[0211] In the first method, first, two substrates are arranged opposite to each other with a gap (cell gap) between the liquid crystal alignment films. Next, the peripheral portions of the two substrates are bonded to each other using a sealant, and a liquid crystal composition is filled into the cell gap defined by the substrate surface and the sealant through an injection hole until the liquid crystal composition contacts the film surface, and then the injection hole is sealed.

[0212] The second method is a method called ODF (One Drop Fill: liquid crystal dripping) method. For example, a UV-curable sealant is applied to a predetermined position on one of the two substrates on which the liquid crystal alignment film is formed, and a liquid crystal composition is further dripped to a predetermined number of positions on the surface of the liquid crystal alignment film. After that, the other substrate is bonded in a manner that the liquid crystal alignment film is opposite, and the liquid crystal composition is pushed to the entire surface of the substrate to contact the film surface. Then, ultraviolet light is irradiated to the entire surface of the substrate to cure the sealant.

[0213] In any of the above methods, it is preferable to further heat to a temperature at which the liquid crystal composition to be used becomes an isotropic phase and then gradually cool to room temperature to remove the flow alignment during liquid crystal filling.

[0214] In addition, when the coating film is subjected to the rubbing treatment, the two substrates are disposed to face each other so that the rubbing directions of the coating films form a predetermined angle, for example, orthogonal or antiparallel, with each other.

[0215] As the sealant, for example, an epoxy resin containing a curing agent and alumina balls as spacers can be used. As the liquid crystal, nematic liquid crystal and smectic liquid crystal can be mentioned, and among them, nematic liquid crystal is preferred.

[0216] As the above-mentioned liquid crystal composition, there is no particular limitation, and various liquid crystal compositions containing at least one liquid crystal compound (liquid crystal molecule) and having a positive or negative dielectric anisotropy can be used. It should be noted that, hereinafter, a liquid crystal composition having a positive dielectric anisotropy is also referred to as a positive liquid crystal, and a liquid crystal composition having a negative dielectric anisotropy is also referred to as a negative liquid crystal.

[0217] Examples of the liquid crystal composition include a liquid crystal composition presenting a nematic phase, a liquid crystal composition presenting a smectic phase, and a liquid crystal composition presenting a cholesteric phase. Among them, a liquid crystal composition presenting a nematic phase is preferred.

[0218] The above-mentioned liquid crystal composition may contain a liquid crystal compound having a fluorine atom, a hydroxyl group, an amino group, a fluorine atom-containing group (for example, a trifluoromethyl group), a cyano group, an alkyl group, an alkoxy group, an alkenyl group, an isothiocyanate group, a heterocyclic ring, a cycloalkane, a cycloolefin, a steroid skeleton, a benzene ring, or a naphthalene ring, and may also contain a compound having two or more rigid sites (mesogenic skeletons) exhibiting liquid crystal properties in the molecule (for example, a bimesogenic compound formed by two rigid biphenyl structures or terphenyl structures linked by an alkyl group).

[0219] From the viewpoint of improving the orientation of the liquid crystal, the above-mentioned liquid crystal composition may further be added with additives. Such additives may include: photopolymerizable monomers such as compounds having polymerizable groups; optically active compounds (e.g., S-811 manufactured by Merck, Inc.); antioxidants; ultraviolet absorbers; pigments; defoamers; polymerization initiators; or polymerization inhibitors, etc.

[0220] Examples of the positive liquid crystal include ZLI-2293, ZLI-4792, MLC-2003, MLC-2041, MLC-3019, and MLC-7081 manufactured by Merck.

[0221] As a negative liquid crystal, MLC-6608, MLC-6609, MLC-6610, or MLC-7026-100 manufactured by Merck is mentioned, for example.

[0222] Moreover, as a liquid crystal containing a compound which has a polymerizable group, MLC-3023 manufactured by Merck can be mentioned.

[0223] Then, by attaching a polarizing plate to the outer surface of the liquid crystal cell as needed, a liquid crystal display element can be obtained. Examples of the polarizing plate attached to the outer surface of the liquid crystal cell include a polarizing film called "H film" that absorbs iodine while stretching polyvinyl alcohol and sandwiched between cellulose acetate protective films, or a polarizing plate composed of the H film itself.

[0224] An IPS substrate, which is a comb-teeth electrode substrate used in the IPS method (mode), includes a substrate, a plurality of linear electrodes formed on the substrate and arranged in a comb-teeth shape, and a liquid crystal alignment film formed on the substrate so as to cover the linear electrodes.

[0225] It should be noted that the FFS substrate, which is a comb-tooth electrode substrate used in the FFS method (mode), has a substrate, a surface electrode formed on the substrate, an insulating film formed on the surface electrode, a plurality of linear electrodes formed on the insulating film and arranged in a comb-tooth shape, and a liquid crystal orientation film formed on the insulating film in a manner covering the linear electrodes.

[0226] Figure 1 This is a schematic cross-sectional view showing an example of an IPS mode transverse electric field liquid crystal display element including a liquid crystal aligning film obtained from the liquid crystal aligning agent of the present invention.

[0227] exist Figure 1 In the lateral electric field liquid crystal display element 1 shown as an example in FIG, a liquid crystal 3 is sandwiched between a comb-tooth electrode substrate 2 having a liquid crystal alignment film 2c and an opposing substrate 4 having a liquid crystal alignment film 4a. The comb-tooth electrode substrate 2 has a substrate 2a, a plurality of linear electrodes 2b formed on the substrate 2a and arranged in a comb-tooth shape, and a liquid crystal alignment film 2c formed on the substrate 2a in a manner covering the linear electrodes 2b. The opposing substrate 4 has a substrate 4b and a liquid crystal alignment film 4a formed on the substrate 4b. The liquid crystal alignment film 2c is the liquid crystal alignment film of the present invention. The liquid crystal alignment film 4c is also the liquid crystal alignment film of the present invention.

[0228] exist Figure 1 In the lateral electric field liquid crystal display element 1, when a voltage is applied to the linear electrodes 2b, an electric field is generated between the linear electrodes 2b as indicated by the electric field lines L.

[0229] Figure 2 This is a schematic cross-sectional view showing an example of a lateral electric field liquid crystal display element of an FFS mode including a liquid crystal aligning film obtained from the liquid crystal aligning agent of the present invention.

[0230] exist Figure 2In the lateral electric field liquid crystal display element 1 shown as an example in FIG, a liquid crystal 3 is sandwiched between a comb-tooth electrode substrate 2 having a liquid crystal alignment film 2h and an opposing substrate 4 having a liquid crystal alignment film 4a. The comb-tooth electrode substrate 2 has a substrate 2d, a surface electrode 2e formed on the substrate 2d, an insulating film 2f formed on the surface electrode 2e, a plurality of linear electrodes 2g formed on the insulating film 2f and arranged in a comb-tooth shape, and a liquid crystal alignment film 2h formed on the insulating film 2f in a manner covering the linear electrodes 2g. The opposing substrate 4 has a substrate 4b and a liquid crystal alignment film 4a formed on the substrate 4b. The liquid crystal alignment film 2h is the liquid crystal alignment film of the present invention. The liquid crystal alignment film 4a is also the liquid crystal alignment film of the present invention.

[0231] exist Figure 2 In the lateral electric field liquid crystal display element 1, when a voltage is applied to the surface electrode 2e and the linear electrode 2g, an electric field is generated between the surface electrode 2e and the linear electrode 2g as indicated by the electric field lines L.

[0232] Example

[0233] The present invention will be described in more detail below with reference to Examples, but the present invention is not limited thereto. The abbreviations of the following compounds and the methods for measuring the properties are as follows.

[0234] (Organic Solvent)

[0235] NMP: N-methyl-2-pyrrolidone.

[0236] GBL: gamma-butyrolactone.

[0237] BCS: ethylene glycol monobutyl ether.

[0238] (Tetracarboxylic dianhydride)

[0239] CA-1 to CA-3: compounds represented by the following formulas (CA-1) to (CA-3), respectively.

[0240]

[0241] (Diamine)

[0242] DA-1 to DA-9: compounds represented by the following formulae (DA-1) to (DA-9), respectively.

[0243]

[0244] (additive)

[0245] AD-1 to AD-4: compounds represented by the following formulae (AD-1) to (AD-4), respectively.

[0246]

[0247] <Viscosity measurement>

[0248] The measurement was performed at a temperature of 25° C. using an E-type viscometer TVE-22H (manufactured by Toki Sangyo Co., Ltd.) with a sample amount of 1.1 mL and a conical rotor TE-1 (1°34′, R24).

[0249] <Determination of molecular weight>

[0250] The measurement was performed using the following room temperature gel permeation chromatography (GPC) apparatus, and Mn and Mw were calculated as polyethylene glycol and polyethylene oxide equivalent values.

[0251] GPC apparatus: GPC-101 (manufactured by Showa Denko K.K.), chromatographic column: GPC KD-803 and GPC KD-805 (manufactured by Showa Denko K.K.) connected in series, chromatographic column temperature: 50°C, eluent: N,N-dimethylformamide (as an additive, lithium bromide monohydrate (LiBr·H2O) is 30 mmol / L, anhydrous phosphoric acid (orthophosphoric acid) is 30 mmol / L, and tetrahydrofuran (THF) is 10 mL / L), flow rate: 1.0 mL / min.

[0252] Standard samples for preparing the calibration curve: TSK standard polyethylene oxide (molecular weight: about 900,000, about 150,000, about 100,000, and about 30,000) (manufactured by TOSOH) and polyethylene glycol (molecular weight: about 12,000, about 4,000, and about 1,000) (manufactured by Polymer Laboratories).

[0253] <Measurement of Imidization Ratio>

[0254] 20 mg of polyimide powder was added to an NMR (nuclear magnetic resonance) sample tube (NMR standard sample tube, φ5 (manufactured by Kusano Scientific Co., Ltd.)), 1.0 mL of deuterated dimethyl sulfoxide ([D6]-DMSO, 0.05% tetramethylsilane (TMS) mixed product) was added, and ultrasonic waves were applied to completely dissolve it. The solution was measured for 500 MHz proton NMR using a Fourier transform superconducting nuclear magnetic resonance device (FT-NMR) "AVANCE III" (manufactured by BRUKER).

[0255] As for the (chemical) imidization rate, a proton derived from a structure that does not change before and after imidization is determined as a reference proton, and the peak integral value of the proton and the peak integral value of the proton derived from the NH group of the amic acid appearing near 9.5 to 10.0 ppm are used to obtain the following formula. It should be noted that in the following formula, x represents the peak integral value of the proton derived from the NH group of the amic acid, y represents the peak integral value of the reference proton, and α represents the ratio of the number of reference protons to one NH proton of the amic acid in the case of a polyamic acid (imidization rate of 0%).

[0256] Imidization rate (%) = (1-α·x / y) × 100

[0257] [Synthesis of polymer]

[0258] <Synthesis example 1>

[0259] DA-1 (0.541 g, 4.43 mmol), DA-2 (4.69 g, 19.2 mmol), DA-3 (2.35 g, 5.91 mmol), CA-1 (6.09 g, 27.2 mmol) and NMP (100 g) were added to a 100 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube, and stirred at 40° C. for 3 hours to obtain a polyamic acid solution having a solid content concentration of 12% by mass (viscosity: 189 mPa·s). The polyamic acid had an Mn of 11012 and an Mw of 38921.

[0260] The solution (40.0 g) of the polyamic acid obtained was measured in a 100 mL four-necked flask with a stirring device and a nitrogen inlet tube, NMP was added in a solid content concentration of 9% by mass, acetic anhydride (3.18 g) and pyridine (0.820 g) were added, and after stirring at room temperature for 30 minutes, it was reacted at 55 ° C for 2 hours. The reaction solution was put into methanol (286 g) and the obtained precipitate was filtered out. The precipitate was washed with methanol and dried under reduced pressure at 80 ° C to obtain a powder of polyimide. The imidization rate of the polyimide powder was 70%, Mn was 12324, and Mw was 40131.

[0261] NMP was added to the obtained polyimide powder so as to have a solid content concentration of 15 mass %, and the mixture was dissolved by stirring at 70° C. for 20 hours to obtain a polyimide (SPI-A1) solution (viscosity: 294 mPa·s). The polyimide had an Mn of 12821 and an Mw of 40182.

[0262] <Synthesis example 2>

[0263] DA-4 (1.28 g, 11.8 mmol), DA-5 (5.29 g, 17.7 mmol), CA-2 (5.44 g, 27.8 mmol) and NMP (88.1 g) were added to a 100 mL four-necked flask equipped with a stirring device and a nitrogen inlet tube, and stirred at room temperature for 3 hours to obtain a solution of polyamic acid (PAA-B1) having a solid content concentration of 12% by mass (viscosity: 130 mPa·s). The Mn of the polyamic acid was 10101 and the Mw was 38321.

[0264] <Synthesis example 3>

[0265] DA-6 (2.35 g, 11.8 mmol), DA-5 (5.29 g, 17.7 mmol), CA-2 (1.74 g, 8.86 mmol) and NMP (84.4 g) were added to a 100 mL four-necked flask with a stirring device and a nitrogen inlet tube, and stirred at room temperature for 1 hour while supplying nitrogen. Then, after cooling to 15°C, CA-3 (5.65 g, 19.2 mmol) and NMP (25.8 g) were added, and stirred at 50°C for 20 hours to obtain a solution of polyamic acid (PAA-B2) with a solid content concentration of 12% by mass (viscosity: 412 mPa·s). The Mn of the polyamic acid is 13102 and the Mw is 43244.

[0266] <Synthesis example 4>

[0267] DA-6 (4.71 g, 23.6 mmol), DA-7 (0.899 g, 5.91 mmol), CA-3 (8.17 g, 27.8 mmol) and NMP (101 g) were added to a 100 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube, and stirred at 70° C. for 15 hours to obtain a solution of polyamic acid (PAA-B3) having a solid content concentration of 12% by mass (viscosity: 389 mPa·s). The polyamic acid had an Mn of 13183 and an Mw of 42917.

[0268] <Synthesis example 5>

[0269] DA-2 (6.13 g, 25.1 mmol), DA-8 (1.05 g, 4.43 mmol), CA-1 (6.06 g, 27.0 mmol) and NMP (97.1 g) were added to a 100 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube, and stirred at 40° C. for 3 hours to obtain a polyamic acid solution having a solid content concentration of 12% by mass (viscosity: 200 mPa·s). The polyamic acid had an Mn of 12901 and an Mw of 38592.

[0270] The solution (40.0 g) of the polyamic acid obtained was measured in a 100 mL four-necked flask with a stirring device and a nitrogen inlet tube, NMP was added in a solid content concentration of 9% by mass, acetic anhydride (3.28 g) and pyridine (0.850 g) were added, and after stirring at room temperature for 30 minutes, it was reacted at 55 ° C for 3 hours. The reaction solution was put into methanol (287 g) and the obtained precipitate was filtered out. The precipitate was washed with methanol and dried under reduced pressure at 80 ° C to obtain a powder of polyimide. The imidization rate of the polyimide powder was 70%, Mn was 13910, and Mw was 40101.

[0271] NMP was added to the obtained polyimide powder (40.0 g) to a solid content concentration of 12 mass %, and the mixture was dissolved by stirring at 70° C. for 20 hours to obtain a polyimide solution (SPI-R1) (viscosity: 140 mPa·s). The polyimide had an Mn of 14578 and an Mw of 40282.

[0272] <Synthesis Example 6>

[0273] DA-3 (2.35 g, 5.90 mmol), DA-2 (2.16 g, 8.86 mmol), DA-9 (2.84 g, 8.86 mmol), DA-4 (0.639 g, 5.91 mmol), CA-1 (6.22 g, 27.8 mmol) and NMP (104 g) were added to a 100 mL four-necked flask equipped with a stirring device and a nitrogen inlet tube, and stirred at 40° C. for 20 hours to obtain a solution of a polyamic acid (PAA-R1) having a solid content concentration of 12% by mass (viscosity: 389 mPa·s). The Mn of the polyamic acid was 14391 and the Mw was 40282.

[0274] The types and amounts of the tetracarboxylic acid derivative components and diamine components used in Synthesis Examples 1 to 6 are shown in Table 1. In Table 1, the numerical values ​​in parentheses represent the usage amounts (parts by mole) of the monomers in each component relative to a total of 100 parts by mole.

[0275] [Table 1]

[0276]

[0277] [Preparation of Liquid Crystal Alignment Agent]

[0278] <Example 1>

[0279] The solution of the polymer (SPI-A1) and the solution of the polymer (PAA-B1) were diluted with NMP, GBL and BCS, and AD-1 to AD-4 were further added, followed by stirring at room temperature for 20 hours, thereby obtaining a liquid crystal aligning agent (V-1), wherein the solid content ratio (mass ratio) of the polymer (SPI-A1) to the polymer (PAA-B1) was 50:50, the mass ratio of the polymer solid content to each solvent (polymer solid content: NMP: GBL: BCS) was 6:49:20:25, and the mixing ratio of AD-1 was 10 parts by mass, the mixing ratio of AD-2 was 1 part by mass, the mixing ratio of AD-3 was 10 parts by mass, and the mixing ratio of AD-4 was 3 parts by mass, relative to 100 parts by mass of the polymer.

[0280] <Example 2, Comparative Examples 1 and 2>

[0281] Except having changed the kind and amount of the polymer, the solvent, and the additive used as shown in Table 2, it carried out similarly to Example 1, and prepared the liquid crystal aligning agent (V-2), (RV-1) - (RV-2).

[0282] [Table 2]

[0283]

[0284] In the table, the numerical values ​​in parentheses of the polymers represent the blending amount (parts by mass) of each polymer relative to 100 parts by mass of the total amount of the polymers.

[0285] [Fabrication of FFS-driven liquid crystal cell]

[0286] A liquid crystal cell having a structure of an FFS mode liquid crystal display element was produced.

[0287] First, prepare a substrate with electrodes. A glass substrate with a rectangular shape of 30 mm × 50 mm and a thickness of 0.7 mm is used as the substrate. On the substrate, an ITO electrode with a dense pattern constituting a common electrode is formed as the first layer. On the common electrode of the first layer, a SiN (silicon nitride) film formed by CVD (chemical vapor deposition) is formed as the second layer. The thickness of the second layer of SiN film is 300 nm, and it functions as an interlayer insulating film. On the second layer of SiN film, a comb-shaped pixel electrode formed by patterning the ITO film is arranged as the third layer, and two types of pixels, a first pixel and a second pixel, are formed, and the size of each pixel is 10 mm long and 5 mm wide. This substrate with electrodes has a structure in which the common electrode of the first layer and the pixel electrode of the third layer are insulated by the SiN film of the second layer.

[0288] The pixel electrode of the third layer has a comb-tooth shape in which multiple electrode lines with a width of 3 μm are arranged in parallel at intervals of 6 μm and bent at an internal angle of 160° in the central part. One pixel is formed by multiple electrode lines and has a first area and a second area with the line connecting the bent parts as the boundary.

[0289] Next, the liquid crystal alignment agents (V-1) to (V-2) and (RV-1) to (RV-2) obtained in the above-mentioned Examples 1 to 2 and Comparative Examples 1 to 2 were filtered using a filter with a pore size of 1.0 μm, and then applied to the above-mentioned substrate with electrodes (hereinafter referred to as the electrode substrate) and a glass substrate with a columnar spacer with a height of 4 μm formed on the back with an ITO film (hereinafter referred to as the counter substrate) by spin coating. After drying on a hot plate at 80°C for 2 minutes, it was calcined in a hot air circulation oven at 230°C for 20 minutes to form a coating film with a film thickness of 100 nm. After irradiating the coating surface with a predetermined amount of polarized ultraviolet rays through a 254nm bandpass filter and a polarizer, the substrate with the film formed was immersed in ethyl lactate for 5 minutes at room temperature, and then immersed in pure water for 1 minute. Then, the above-mentioned substrate was calcined in a hot air circulation oven at 230°C for 20 minutes to obtain a substrate with a liquid crystal alignment film. The irradiation amount of polarized ultraviolet rays is shown in Table 3 below. It should be noted that, for the liquid crystal alignment film formed on the electrode substrate, the orientation treatment was carried out in a manner that the direction of bisecting the inner angle of the pixel bending portion was orthogonal to the orientation direction of the liquid crystal, and for the liquid crystal alignment film formed on the opposing substrate, the orientation treatment was carried out in a manner that the orientation direction of the liquid crystal on the electrode substrate was consistent with the orientation direction of the liquid crystal on the opposing substrate when making the liquid crystal box. The above two substrates were used as a group, and a sealant (XN-1500T manufactured by Mitsui Chemicals Co., Ltd.) was printed on the substrate using a dispensing machine, and another substrate was bonded in a manner that the orientation direction of each liquid crystal alignment film became 0° and faced each other. Then, the bonded substrates were pressed and heated in a hot air circulation oven at 150°C for 60 minutes to cure the sealant and make an empty box. Negative liquid crystal MLC-7026-100 (manufactured by Merck) was injected into the empty box by a reduced pressure injection method, and the injection port was sealed to obtain an FFS driven liquid crystal box. Then, the obtained liquid crystal box was heated at 120°C for 1 hour, and was placed at 23°C overnight for evaluation.

[0290] [Evaluation of In-plane Uniformity of Contrast]

[0291] AxoStep manufactured by AXOMETRICS was used to evaluate the uneven twist angle of the liquid crystal box. The liquid crystal box produced above was placed on a measuring table, and the distribution of circular retardation (Circular Retardance) in the pixel surface was measured without applying voltage, and 3σ, which is three times the standard deviation σ, was calculated. It can be said that the smaller the value of 3σ, the better the uniformity in the surface. As an evaluation criterion, the case where the 3σ value is less than 1.80 is set to "○", and the case where the 3σ value is greater than 1.80 is set to "×". The results are shown in Table 3.

[0292] [Evaluation of film surface flatness]

[0293] The liquid crystal alignment agents (V-1) to (V-2) and (RV-1) obtained in the above-mentioned Examples 1 to 2 and Comparative Examples 1 to 2 were filtered using a filter with a pore size of 1.0 μm, and then applied to a 30 mm × 40 mm rectangular glass substrate with a thickness of 1.1 mm by spin coating. After drying on a hot plate at 80°C for 2 minutes, the mixture was calcined in a hot air circulation oven at 230°C for 20 minutes to form a coating with a film thickness of 100 nm. After irradiating the coating surface with a prescribed amount of polarized ultraviolet light through a 254 nm bandpass filter and a polarizer, the substrate with the film formed thereon was immersed in ethyl lactate for 5 minutes at room temperature, and then immersed in pure water for 1 minute. Then, the above-mentioned substrate was calcined in a hot air circulation oven at 230°C for 20 minutes to obtain a substrate with a liquid crystal alignment film. The irradiation amount of polarized ultraviolet light is shown in Table 3 below. The surface of the coating film was observed using an atomic force microscope (AFM, L-trace probe microscope manufactured by SII Technology) to measure the centerline average roughness (Ra) of the film surface and evaluate the flatness of the film surface. It can be said that the smaller the centerline average roughness (Ra) value, the better the flatness of the film surface.

[0294] As evaluation criteria, a case where the Ra value was less than 1.00 nm was rated as “○”, and a case where the Ra value was 1.00 nm or more was rated as “×”.

[0295] [Table 3]

[0296]

[0297] As shown in Table 3 above, the liquid crystal alignment films obtained from the liquid crystal alignment agents (V-1) to (V-2) containing the polyimide (A) and the polyamic acid (B) having a specific structure are compared with the liquid crystal alignment films obtained from the liquid crystal alignment agents (RV-1) to (RV-2) not containing the polyimide (A). The ultraviolet irradiation amount is less than 450 mJ / cm 2 The in-plane contrast is stable and the film surface has excellent flatness.

[0298] Industrial Applicability

[0299] By using the liquid crystal aligning agent of the present invention, it is possible to obtain a liquid crystal aligning agent having a strength of less than 450 mJ / cm 2 The liquid crystal alignment film with stable contrast in the plane within the low irradiation area. In addition, a liquid crystal alignment film formed by a specific liquid crystal alignment agent comprising polyimide and polyamic acid obtained by using substituted cyclobutane tetracarboxylic dianhydride or its derivatives as raw materials can be obtained, and the surface has few concavoconvex liquid crystal alignment films. Therefore, it can be expected that the liquid crystal display elements requiring high display quality grades, especially the IPS drive mode and the FFS drive mode liquid crystal display elements are utilized. In addition, these elements are also useful in liquid crystal displays for the purpose of display, dimming windows for controlling the transmission and isolation of light, optical shutters, etc.

[0300] Description of Reference Numerals

[0301] 1: lateral electric field liquid crystal display element; 2: comb-tooth electrode substrate; 2a: substrate; 2b: linear electrode; 2c: liquid crystal orientation film; 2d: substrate; 2e: surface electrode; 2f: insulating film; 2g: linear electrode; 2h: liquid crystal orientation film; 3: liquid crystal; 4: opposing substrate; 4a: liquid crystal orientation film; 4b: substrate; L: electric field line.

[0302] It should be noted that the entire contents of the specification, claims, drawings, and abstract of Japanese Patent Application No. 2022-125633 filed on August 5, 2022 are cited herein and introduced as a disclosure of the specification of the present invention.

Claims

1. A liquid crystal alignment agent, characterized in that: Contains the following components A and B, Component A: a polyimide A having either or both of a repeating unit a1 represented by the following formula (1) and an imidized structural unit of the repeating unit a1, and either or both of a repeating unit a2 represented by the following formula (2) and an imidized structural unit of the repeating unit a2, The total amount of the repeating unit a1 and the imidized structural unit of the repeating unit a1 is 10 to 40 mol% of all the repeating units of the polyimide A. The total amount of the repeating unit a2 and the imidized structural unit of the repeating unit a2 is 60 to 90 mol% of all the repeating units of the polyimide A. Component B: polyamic acid B having a repeating unit b1 represented by the following formula (5), In formula (1), R and Z each independently represent a hydrogen atom or a monovalent organic group, In formula (2), R and Z have the same meanings as in formula (1); Y2 represents a divalent organic group represented by the following formula (2m), Any hydrogen atom on the benzene ring described in formula (2m) is optionally substituted by a halogen atom or a monovalent organic group; * represents a bonding bond, In formula (5), X5 is a tetravalent organic group, Y5 is a divalent organic group; and Z has the same meaning as Z in formula (1).

2. The liquid crystal alignment agent according to claim 1, wherein The polyimide A further comprises at least one selected from the group consisting of a repeating unit ar represented by the following formula (Ar), a repeating unit a2' represented by the following formula (2'), a repeating unit a3 represented by the following formula (3), and imidized structural units thereof, In the formula (Ar), R and Z have the same meanings as in the formula (1); Y2 represents a divalent organic group represented by the following formula (O), which does not include the divalent organic group represented by the formula (2m); *-Ar-Q2-Ar-* (O) In the formula (O), Ar each independently represents a benzene ring, a biphenyl structure, or a naphthalene ring; any hydrogen atom on the Ar ring is optionally substituted by a halogen atom or a monovalent organic group; Q2 represents -(CH2) n -, or the -(CH2) is substituted by any one of -O-, -C(=O)- or -OC(=O)- n -, the -(CH2) n -, n is 2 to 18; * indicates a bonding key, In formula (2') and (3), X 2’ , X3 represents a tetravalent organic group, Y 2’ represents a divalent organic group represented by the following formula (O2), Y3 represents a divalent organic group having a group "-N(D)-" in the molecule and having 6 to 30 carbon atoms excluding D, wherein D in the -N(D)- represents a carbamate-based protecting group; R and Z have the same meanings as in the case of the formula (1), In formula (O2), m is an integer from 0 to 2, Ar 2’ represents an unsubstituted or substituted benzene ring; wherein, when m is 0, Ar 2’ represents an unsubstituted benzene ring. When m is 1 or 2, Ar 2’ Each independently represents an unsubstituted benzene ring, or a benzene ring in which any hydrogen atom on the benzene ring is substituted with a halogen atom or a monovalent organic group; Q 2’ Indicates a single bond or -O-; in the presence of multiple Ar 2’ , Q 2’ In the case of , each is optionally the same or different; * represents a bonding bond.

3. The liquid crystal alignment agent according to claim 1, wherein The X5 is a tetravalent organic group derived from a non-cyclic aliphatic tetracarboxylic dianhydride, a tetravalent organic group derived from an alicyclic tetracarboxylic dianhydride, or a tetravalent organic group derived from an aromatic tetracarboxylic dianhydride.

4. The liquid crystal alignment agent according to claim 1, wherein The X5 is a tetravalent organic group having at least one partial structure selected from the group consisting of a benzene ring, a cyclobutane ring structure, a cyclopentane ring structure, and a cyclohexane ring structure.

5. The liquid crystal alignment agent according to claim 1, wherein The Y5 is a divalent organic group derived from the following compounds, wherein the compound is a diamine having a urea bond, a diamine having an amide bond, a diamine having a structure containing a nitrogen atom, 2,4-diaminophenol, 3,5-diaminophenol, 3,5-diaminobenzyl alcohol, 2,4-diaminobenzyl alcohol, 4,6-diaminoresorcinol, a diamine having a carboxyl group, 4,4'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 3,3'-dimethyl-4,4'-diaminodiphenylmethane, p-phenylenediamine or m-phenylenediamine.

6. The liquid crystal alignment agent according to claim 1, wherein The liquid crystal alignment agent further contains a crosslinking compound, which is at least one compound selected from the group consisting of a compound having the following group and a compound represented by the following formula (e), wherein the group is at least one group selected from the group consisting of an oxirane group, an oxetane group, a protected isocyanate group, a protected isothiocyanate group, a group containing an oxazoline ring structure, a group containing a Michaelis acid structure, a cyclocarbonate group, and a group represented by the following formula (d), In formula (d), R2 and R3 are each independently a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or "*-CH2-OH", In formula (e), A represents an m+n-valent organic group having an aromatic ring, R and R' each independently represent a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, m is 1 to 6, and n is 0 to 4; any hydrogen atom of the aromatic ring is optionally substituted by 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, or a fluoroalkoxy group having 1 to 10 carbon atoms; and * represents a bonding bond.

7. The liquid crystal alignment agent according to claim 1, wherein: The liquid crystal alignment agent is used for a liquid crystal alignment film used in a photo-alignment treatment method. 8 . A liquid crystal alignment film obtained from the liquid crystal alignment agent according to claim 1 . 9 . A liquid crystal display element comprising the liquid crystal alignment film according to claim 8 .

10. A method for manufacturing a liquid crystal alignment film, wherein the liquid crystal alignment film is a liquid crystal alignment film for a liquid crystal display element, wherein: The method comprises the following steps 1 to 3, Step 1: a step of applying the liquid crystal aligning agent according to any one of claims 1 to 7 onto a substrate, Step 2: a step of firing the applied liquid crystal alignment agent. Step 3: A step of subjecting the film obtained in step 2 to an orientation treatment as necessary.

11. The method for manufacturing a liquid crystal alignment film according to claim 10, wherein: The alignment treatment is a photo-alignment treatment.

12. The method for manufacturing a liquid crystal alignment film according to claim 11, wherein: The radiation dose in the photo-alignment treatment is 100 to 450 mJ / cm 2 .

13. The method for manufacturing a liquid crystal alignment film according to claim 10, wherein: The step of contacting with a solvent is also included.

14. The method for manufacturing a liquid crystal alignment film according to claim 10, wherein: After step 3, step 4 of performing a heat treatment is further included.

15. The method for manufacturing a liquid crystal alignment film according to claim 10, wherein: The liquid crystal display element is an IPS driving mode or a FFS driving mode liquid crystal display element.

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