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

Abstract

The present invention is a liquid crystal alignment agent that contains a polymer (P) that includes at least one chosen from the group consisting of polyimide precursors and polyimides obtained using a diamine constituent including a diamine (1) represented by formula (1). (Ar represents a phenylene group; Q represents a bivalent organic group that includes one or more naphthalene rings; Q and each of two oxygen atoms are bound onto a benzene ring that forms the one or more naphthalene rings; and the benzene ring bound to one of the oxygen atoms and the benzene ring bound to the other oxygen atom differ. Any hydrogen atom on the phenylene group may be substituted with at least one chosen from the group consisting of alkyl groups with carbon numbers from 1 to 3, alkoxy groups with carbon numbers from 1 to 3, fluorine-containing alkyl groups with carbon numbers from 1 to 3, fluorine-containing alkoxy groups with carbon numbers from 1 to 3, and a fluorine atom.)

Description

[Technical field]

[0001] The present invention relates to a liquid crystal aligning agent, a liquid crystal alignment film obtained from the liquid crystal aligning agent, and a liquid crystal display device having the liquid crystal alignment film. [Background technology]

[0002] Liquid crystal display elements are widely used in a wide range of applications, from small applications such as mobile phones and smartphones to relatively large applications such as televisions and monitors. Liquid crystal display elements are generally constructed by arranging a pair of electrode substrates facing each other with a predetermined gap (several μm) between them and sealing liquid crystal between the electrode substrates. Display on the liquid crystal display element is performed by applying a voltage between the transparent conductive films constituting the electrodes of the electrode substrates. These liquid crystal display elements have a liquid crystal alignment film that is essential for controlling the alignment state of liquid crystal molecules.

[0003] Meanwhile, various driving methods have been developed for liquid crystal display elements, which differ in electrode structure, physical properties of the liquid crystal molecules used, etc. For example, various modes such as the Twisted Nematic (TN) method, the Super Twisted Nematic (STN) method, the Vertical Alignment (VA) method, the In-Plane Switching (IPS) method, and the FFS (fringe field switching) method are known. In particular, VA (vertical alignment) type liquid crystal display elements have a wide viewing angle, fast response speed, high contrast, and do not require rubbing processing in the production process, so they are widely used, especially in televisions and monitors, where there is a high demand for larger displays. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2008 / 117615 [Patent Document 2] JP 2008-76950 A Summary of the Invention [Problem to be solved by the invention]

[0005] Incidentally, the above-mentioned transparent conductive film in a liquid crystal display element is usually formed of a composition (ITO) in which indium oxide is the main component and is doped with a few percent of tin oxide, and the refractive index of the film is different from that of the liquid crystal alignment film and has a high value. Therefore, when light from a display light source is transmitted through the electrode substrate, the light is reflected at the interface between the transparent conductive film and the liquid crystal alignment film in each electrode substrate. As a result, the light transmittance of the electrode substrate cannot be sufficiently obtained, leading to a problem of a decrease in display brightness. In particular, ultra-high definition panels such as 4K and 8K have been developed in recent years, but these panels require a large occupancy rate of black matrix (BM) and TFT (Thin Film Transistor), which reduces the aperture ratio of the panel, so improving the transmittance of the display area is becoming important.

[0006] Therefore, the present inventors have investigated various materials for forming the liquid crystal alignment film in order to increase the refractive index of the liquid crystal alignment film, from the viewpoint that the above-mentioned problems can be solved by reducing the difference between the refractive index of the transparent conductive film and the refractive index of the liquid crystal alignment film. Specifically, in order to increase the refractive index of the liquid crystal alignment film, various types of polymers to be contained in the liquid crystal alignment agent forming the liquid crystal alignment film have been searched for.

[0007] As a result, by selecting a specific polymer, it was possible to obtain a liquid crystal alignment film having a refractive index close to that of the transparent conductive film. However, on the other hand, it became clear that polymers that form liquid crystal alignment films with high refractive indexes do not have very good solubility in the solvent components of the liquid crystal alignment agent, and therefore tend to be inferior in terms of the storage stability of the liquid crystal alignment agent and the coatability (printability) on the substrate, leaving room for further improvement.

[0008] In view of the above circumstances, an object of the present invention is to provide a liquid crystal alignment agent which has good solubility of the components contained in the liquid crystal alignment agent and can form a liquid crystal alignment film having a high refractive index, a liquid crystal alignment film obtained from the liquid crystal alignment agent, and a liquid crystal display element having the liquid crystal alignment film. [Means for solving the problem]

[0009] As a result of intensive research into achieving the above object, the present inventors have found that a liquid crystal aligning agent containing a polymer having a specific structure is effective for achieving the above object, and have completed the present invention. The present invention relates to a liquid crystal aligning agent characterized by containing a polymer (P) containing at least one selected from the group consisting of polyimide precursors and polyimides obtained by using a diamine component containing diamine (1) (hereinafter also referred to as specific diamine) represented by the following formula (1); a liquid crystal alignment film obtained from the liquid crystal aligning agent; and a liquid crystal display element having the liquid crystal alignment film. [ka] (Ar represents a phenylene group, Q represents a divalent organic group containing at least one naphthalene ring, Q and each of the two oxygen atoms are bonded to a benzene ring constituting the at least one naphthalene ring, and the benzene ring bonded to one of the oxygen atoms is different from the benzene ring bonded to the other oxygen atom. Any hydrogen atom on the phenylene group may be substituted with at least one selected from the group consisting of an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a fluorine-containing alkyl group having 1 to 3 carbon atoms, a fluorine-containing alkoxy group having 1 to 3 carbon atoms, and a fluorine atom.) Effect of the Invention

[0010] According to the present invention, a liquid crystal aligning agent is obtained which has good solubility of the components contained therein and can form a liquid crystal alignment film having a high refractive index. Since the liquid crystal alignment film formed from such a liquid crystal aligning agent has a high refractive index, the difference between the refractive index of the transparent conductive film in a liquid crystal display element and the refractive index of the liquid crystal alignment film can be reduced, and a liquid crystal display element with excellent display quality can be obtained. Although the mechanism by which the above-mentioned effects of the present invention are obtained is not entirely clear, the following is believed to be one of the reasons: In other words, in the polymer of the present invention, the naphthalene ring is arranged at the center of the diamine molecule, not at the bonding position of the amino group, which is thought to reduce the packing property of the polymer and improve the solubility, and also to increase the refractive index of the liquid crystal alignment film obtained by introducing the naphthalene ring. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, the liquid crystal alignment agent of the present invention, the liquid crystal alignment film obtained from the liquid crystal alignment agent, and the liquid crystal display element having the liquid crystal alignment film will be described in detail. However, the explanation of the constituent elements described below is an example of one embodiment of the present invention, and the present invention is not limited to these contents. In the following description, Boc represents a tert-butoxycarbonyl group. Furthermore, examples of the "halogen atom" include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

[0012] (Liquid crystal alignment agent) The liquid crystal aligning agent of the present invention contains a polymer (P) and further contains other components as required.

[0013] (Polymer (P)) The polymer (P) contains at least one selected from the group consisting of polyimide precursors obtained using a diamine component and polyimides. The polymer (P) is at least one selected from the group consisting of polyimide precursors and polyimides, and may be one component or two or more components.

[0014] (Diamine component) The diamine component contains a diamine (1) represented by the following formula (1). [ka] (In the above formula (1), Ar and Q are as defined above.)

[0015] Among these, from the viewpoint of obtaining the effects of the present invention, Q preferably has 10 to 40 carbon atoms, and Q is more preferably a divalent organic group having 10 to 40 carbon atoms and represented by the following formula (f). [ka] (A 1 and A 2 Each of X is independently a naphthalene ring which may have a substituent. 1 and X 2 are each independently a single bond, an oxygen atom or a sulfur atom. Y is an alkylene group having 1 to 8 carbon atoms, or a divalent organic group containing an oxygen atom or a sulfur atom between the carbon-carbon bond of an alkylene group having 1 to 8 carbon atoms. m is an integer of 0 to 2, and n is an integer of 0 or 1. * represents a bond.

[0016] The naphthalene ring may have a substituent. Examples of the substituent that the naphthalene ring may have include an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, and a halogen atom. X 1 and X 2 is preferably an oxygen atom.

[0017] Preferred specific examples of the diamine (1) represented by the above formula (1) include the following formulae (d-1) and (d-2). [ka]

[0018] When the polymer (P) contained in the liquid crystal alignment agent of the present invention is applied to a liquid crystal alignment agent for a liquid crystal display element of a TN mode, STN mode, VA mode, PSA mode, or SC-PVA mode, it is preferable that the polymer (P) contains, as a constituent, a diamine (s) having at least one selected from the group consisting of partial structures represented by the following formulas (S1) to (S3) in addition to the diamine represented by the above formula (1). In the polymer (P), the diamine (s) may be at least one constituent selected from the group consisting of polyimide precursors and polyimides containing the diamine (1) as a constituent, or at least one constituent selected from the group consisting of polyimide precursors and polyimides different from the at least one selected from the group consisting of polyimide precursors and polyimides containing the diamine (1) as a constituent. [ka]

[0019] In formula (S1), X 1 and X 2 are each independently a single bond, -(CH 2 ) a -(a is an integer from 1 to 15), -CONH-, -NHCO-, -CON(CH 3 )-, -N(CH 3 )CO-, -NH-, -O-, -COO-, -OCO-, -((CH 2 ) a1 -A 1 ) m1 - or - (A 1 -(CH 2 ) a1 ) m1 - [a1 is an integer from 1 to 15, A 1 represents an oxygen atom, -COO-, or -OCO-, and m1 is an integer of 1 to 2. When m1 is 2, each of the multiple a1's is independently 1 are independent of each other.]. G 1 and G 2each independently represents a divalent cyclic group selected from a divalent aromatic group having 6 to 12 carbon atoms and a divalent alicyclic group having 3 to 8 carbon atoms. Any hydrogen atom on the cyclic group may be substituted with at least one selected from the group consisting of an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a fluorine-containing alkyl group having 1 to 3 carbon atoms, a fluorine-containing alkoxy group having 1 to 3 carbon atoms, and a fluorine atom. each independently represents an integer of 0 to 3, and the sum of m and n is 1 to 6. From the viewpoint of enhancing the liquid crystal alignment property, the sum of m and n is preferably 2 to 6, and more preferably 2 to 4. R 1 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; R 1 Any hydrogen atom forming the formula (I) may be substituted with a fluorine atom. Also, G 1 , G 2 Examples of the divalent cyclic group in include a cyclopropylene group, a cyclohexylene group, and a phenylene group. Any hydrogen atom on these cyclic groups may be substituted with an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a fluorine-containing alkyl group having 1 to 3 carbon atoms, a fluorine-containing alkoxy group having 1 to 3 carbon atoms, or a fluorine atom.

[0020] [ka] In formula (S2), X 3 is a single bond, -CONH-, -NHCO-, -CON(CH 3 )-, -N(CH 3 )CO-, -NH-, -O-, -CH 2 R represents -O-, -COO- or -OCO-. 2 represents an alkyl group having 1 to 20 carbon atoms or an alkoxyalkyl group having 2 to 20 carbon atoms; R 2 Any hydrogen atom forming the formula (I) may be substituted with a fluorine atom. Also, R 2 From the viewpoint of improving the liquid crystal alignment property, the alkyl group having 3 to 20 carbon atoms or an alkoxyalkyl group having 2 to 20 carbon atoms is preferable.

[0021] [ka] In formula (S3), X 4 -CONH-, -NHCO-, -O-, -COO-, -OCO-, -((CH 2 ) a1 -A 1 ) m1 - or - (A 1 -(CH 2 ) a1 ) m1 - [a1 is an integer from 1 to 15, A 1 represents an oxygen atom, -COO-, or -OCO-, and m1 is an integer of 1 to 2. When m1 is 2, each of the multiple a1's is independently 1 are independent of each other. R 3 represents a structure having a steroid skeleton. 3 is preferably a structure containing a cholestanyl group, a cholesteryl group or a lanostannyl group.

[0022] Preferred specific examples of formula (S1) include the following formulae [S1-x1] to [S1-x7]. [ka]

[0023] In the above formula, R 1 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. p is -(CH 2 ) a -(a is an integer from 1 to 15), -CONH-, -NHCO-, -CON(CH 3 )-, -NH-, -O-, -CH 2 O-, -CH 2 It represents OCO-, -COO-, or -OCO-. 1 is an oxygen atom or -COO-* (where the bond marked with "*" is (CH 2 ) a2 (combines with), A 2is an oxygen atom or *-COO- (where the bond marked with "*" is (CH 2 ) a2 each of a1 and a3 independently represents an integer of 0 or 1, a2 represents an integer of 1 to 10, and Cy represents a 1,4-cyclohexylene group or a 1,4-phenylene group.

[0024] A preferred specific example of the above formula (S3) is the following formula [S3-x]. In the formula [S3-x], X is a group represented by the formula [X1], the formula [X2], or -CH 2 represents -O-, Col represents the formula [Col1], the formula [Col2] or the formula [Col3], and G represents the formula [G1], the formula [G2], the formula [G3] or the formula [G4]. In the formula, "Me" represents a methyl group. * represents a bond.

[0025] [ka]

[0026] The preferred diamine (s) having the partial structure represented by the above formulae (S1) to (S3) is a diamine having the partial structure represented by the above formulae (S1) to (S3) and having at least one benzene ring. The diamine (s) may be a diamine represented by the following formula (d1) or formula (d2). [ka]

[0027] In the formulae (d1) and (d2), Y represents a side chain structure represented by the above formulae (S1) to (S3). X represents a single bond, -O-, -C(CH 3 ) 2 -, -NH-, -CO-, -COO-, -CONH-, -(CH 2 ) m -, -SO 2 -, -O-(CH 2 ) m -O-, -OC(CH 3 ) 2 -, -CO-(CH 2 ) m-, -CO-(CH 2 ) m -CO-, -NH-(CH 2 ) m -, -NH-(CH 2 ) m -NH-, -SO 2 -(CH 2 ) m -, -SO 2 -(CH 2 ) m -SO 2 -,-CONH-(CH 2 ) m -,-CONH-(CH 2 ) m -NHCO- or -COO-(CH 2 ) m It represents -OCO-, and m is an integer of 1 to 8. In the above formula (d2), the two Ys may be the same or different.

[0028] Preferred specific examples of the diamine of the above formula (d1) include the following formulas (d1-1) to (d1-18). [ka] (n is an integer from 1 to 20.)

[0029] [ka]

[0030] The diamine represented by the above formula (d2) may have a structure selected from the group consisting of the following formulae (d2-1) to (d2-6). [ka]

[0031] In the above formula, X p1 ~X p8 is -(CH 2 ) a -(a is an integer from 1 to 15), -CONH-, -NHCO-, -CON(CH 3)-, -NH-, -O-, -CH 2 O-, -CH 2 X represents -OCO-, -COO-, or -OCO-. s1 ~X s4 Each independently represents -O-, -COO- or -OCO-. X a ~X f is a single bond, -O-, -NH-, or -O-(CH 2 ) m -O- (m is an integer of 1 to 8). 1a ~R 1h 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.

[0032] (Production of Polymer (P)) The polymer (P) contained in the liquid crystal aligning agent of the present invention may be composed of one or more polyimide precursors and polyimide which is an imidized product of the polyimide precursor. Here, the polyimide precursor is a polymer which can obtain a polyimide by imidizing a polyamic acid, a polyamic acid ester, etc. More preferred specific embodiments of the polymer (P) are listed below, but the present invention is not limited thereto.

[0033] at least one polymer (hereinafter also referred to as a copolymer) selected from the group consisting of a polyimide precursor obtained by using a diamine component containing the diamine (1) and the diamine (s), and a polyimide which is an imidized product of the polyimide precursor; A mixture (hereinafter also referred to as a polymer blend) of at least one polymer (p-1) selected from the group consisting of a polyimide precursor obtained by using a diamine component containing the above diamine (1) and a polyimide which is an imidized product of the polyimide precursor, and at least one polymer (p-2) selected from the group consisting of a polyimide precursor obtained by using a diamine component containing the above diamine (s) and a polyimide which is an imidized product of the polyimide precursor, and the like. The above copolymers or polymer blends may be used alone or in combination.

[0034] The polyamic acid (P), which is a polyimide precursor of the polymer (P), can be obtained by a polymerization reaction between a diamine component containing the diamine (1) (preferably a diamine component containing diamine (s) in addition to the diamine (1)) and a tetracarboxylic acid component. In this case, the amount of diamine (1) used is preferably from 1 to 100 mol %, more preferably from 1 to 99 mol %, and even more preferably from 5 to 95 mol %, based on the diamine component to be reacted with the tetracarboxylic acid component.

[0035] When diamine (s) is used in addition to the diamine (1), the amount of diamine (s) used is preferably 1 to 99 mol %, more preferably 1 to 95 mol %, based on the diamine component to be reacted with the tetracarboxylic acid component.

[0036] The diamine component used in the production of the polyamic acid (P) may contain diamines other than the diamine (1) and the diamine (s) (hereinafter, these are also referred to as other diamines). Examples of other diamines are given below, but the present invention is not limited thereto.

[0037] Diamines having a carboxy group, such as p-phenylenediamine, m-phenylenediamine, 4-(2-(methylamino)ethyl)aniline, 2,4-diaminobenzoic acid, 2,5-diaminobenzoic acid, 3,5-diaminobenzoic acid, and diamine compounds represented by the following formulae (3b-1) to (3b-4); 4,4'-diaminodiphenylmethane, 3,3'-diaminodiphenylmethane, 4,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl ether; 1,2-bis(4-aminophenyl)ethane, 1,3-bis(4-aminophenyl) Propane, 1,4-bis(4-aminophenyl)butane, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 1,2-bis(4-aminophenoxy)ethane, 1,2-bis(4-amino-2-methylphenoxy)ethane, 1,3-bis(4-aminophenoxy)propane, 1,4-bis(4-aminophenoxy)butane, 1,5-bis(4-aminophenoxy)pentane, 1,6-bis(4-aminophenoxy)hexane, 4-(2-(4-aminophenoxy)ethoxy)-3-fluoroaniline, Di(2-(4-aminophenoxy)ethyl)ether, 4-amino-4'-(2-(4-aminophenoxy)ethoxy)biphenyl, 2,2'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dimethyl-4,4'-diaminobiphenyl, 4,4'-diamino-2,2'-bis(trifluoromethyl)biphenyl, 1,4-diaminonaphthalene, 1,5-diaminonaphthalene, 2,6-diaminonaphthalene, 2,7-diaminonaphthalene, diamines represented by the following formulas (NH-1) to (NH-6), 2,2'-bis[4-(4-aminophenoxy diamines having a urea bond such as 2,2'-bis[4-(4-aminophenoxy)phenyl]propane, 2,2'-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane, 2,2'-bis(4-aminophenyl)propane, and 1,3-bis(4-aminophenethyl)urea; diamines having a photopolymerizable group at the end such as 2-(2,4-diaminophenoxy)ethyl methacrylate and 2,4-diamino-N,N-diallylaniline; diamines having a radical initiation function such as those represented by the following formulas (R1) to (R5); 4,4'-diaminobenzophenone, 3,3'-diaminobenzophenone, 9,Diamines having a photosensitizing function that exhibits a sensitizing effect upon irradiation with light, such as 9-bis(4-aminophenyl)fluorene, 2,6-diaminopyridine, 3,4-diaminopyridine, 2,4-diaminopyrimidine, 3,6-diaminocarbazole, N-methyl-3,6-diaminocarbazole, diamines having heterocycles such as those of the following formulae (z-1) to (z-18), diamines having a diphenylamine skeleton such as those of the following formulae (Dp-1) to (Dp-9), diamines having a group "-N(Boc)" such as those of the following formulae (5-1) to (5-10), diamines having an oxazoline structure such as those of the following formulae (Ox-1) to (Ox-2), and diamines described in International Publication No. WO 2016 / 125870. [ka] (In formula (3b-1), A 1 is a single bond, -CH 2 -, -C 2 H 4 -, -C(CH 3 ) 2 -, -CF 2 -, -C(CF 3 ) 2 -, -O-, -CO-, -NH-, -N(CH 3 )-, -CONH-, -NHCO-, -CH 2 O-, -OCH 2 -, -COO-, -OCO-, -CON(CH 3 )- or -N(CH 3 )CO-, m1 and m2 each independently represent an integer of 0 to 4, and m1+m2 represents an integer of 1 to 4. In formula (3b-2), m3 and m4 each independently represent an integer of 1 to 5. In formula (3b-3), A 2 represents a linear or branched alkyl group having 1 to 5 carbon atoms, and m5 represents an integer of 1 to 5. 3 and A 4 are each independently a single bond, -CH 2 -, -C 2 H 4 -, -C(CH 3 ) 2 -, -CF 2 -, -C(CF 3 ) 2-, -O-, -CO-, -NH-, -N(CH 3 )-, -CONH-, -NHCO-, -CH 2 O-, -OCH 2 -, -COO-, -OCO-, -CON(CH 3 )- or -N(CH 3 )CO-, and m6 represents an integer of 1 to 4. [ka] [ka] [ka] [ka] (n is an integer from 1 to 6.) [ka] [ka] [ka]

[0038] Among these, from the viewpoint of suitably obtaining the effects of the present invention, the other diamines preferably include p-phenylenediamine, 3,5-diaminobenzoic acid, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl ether, 4,4'-diaminobenzophenone, 2,2'-dimethyl-4,4'-diaminobiphenyl, 2-(2,4-diaminophenoxy)ethyl methacrylate, 2,4-diamino-N,N-diallylaniline, diamines represented by the above formulae (R1) to (R5), diamines represented by the above formulae (z-1) to (z-18), diamines represented by the above formulae (5-1) to (5-10), and diamines represented by the above formulae (Ox-1) to (Ox-2). When other diamines are used in addition to the diamine (1), the amount of the other diamines used is preferably 1 to 99 mol %, more preferably 5 to 95 mol %, based on the total diamine components used. When other diamines are used in addition to the diamine (1) and diamine (s), the amount of diamine (s) used is preferably 98 mol % or less, more preferably 94 mol % or less, based on the diamine components to be reacted with the tetracarboxylic acid component.

[0039] The amount of the diamine represented by the above formulas (5-1) to (5-10) used is preferably 5 to 40 mol %, more preferably 10 to 40 mol %, based on the total diamine components used in the production of the polyamic acid (P).

[0040] In liquid crystal display elements using the PSA system or SC-PVA mode, from the viewpoint of increasing the response speed, one or more of 4,4'-diaminobenzophenone, 3,3'-diaminobenzophenone, diamines having a photopolymerizable group at an end, diamines represented by the above formulae (R1) to (R5), and diamines represented by the above formulae (z-1) to (z-18) can be used when producing the polyamic acid (P), and the amount used is preferably 1 to 40 mol %, more preferably 5 to 40 mol %, based on the total diamine components used in the production of the polyamic acid (P).

[0041] (Tetracarboxylic acid component) When producing the above polyamic acid (P), the tetracarboxylic acid component to be reacted with the diamine component may be not only a tetracarboxylic acid dianhydride but also a derivative of a tetracarboxylic acid dianhydride such as a tetracarboxylic acid, a tetracarboxylic acid dihalide, a tetracarboxylic acid dialkyl ester, or a tetracarboxylic acid dialkyl ester dihalide.

[0042] The tetracarboxylic acid dianhydride or its derivative may be an aromatic, aliphatic or alicyclic tetracarboxylic acid dianhydride or a derivative thereof. Here, the aromatic tetracarboxylic acid dianhydride is an acid dianhydride obtained by intramolecular dehydration of four carboxy groups including at least one carboxy group bonded to an aromatic ring. The aliphatic tetracarboxylic acid dianhydride is an acid dianhydride obtained by intramolecular dehydration of four carboxy groups bonded to a chain hydrocarbon structure. However, it is not necessary for the structure to be composed only of a chain hydrocarbon structure, and it may have an alicyclic structure or an aromatic ring structure as a part of it.

[0043] In addition, an alicyclic tetracarboxylic acid dianhydride is an acid dianhydride obtained by intramolecular dehydration of four carboxy groups, including at least one carboxy group bonded to an alicyclic structure. However, none of these four carboxy groups are bonded to an aromatic ring. In addition, it is not necessary for the alicyclic structure to be composed only of an alicyclic structure, and it may have a chain hydrocarbon structure or an aromatic ring structure as a part of the alicyclic structure.

[0044] Among them, the tetracarboxylic dianhydride or derivative thereof is preferably one represented by the following formula (T): That is, the polymer (P) preferably contains a tetracarboxylic acid component containing the tetracarboxylic dianhydride represented by the formula (T) as a constituent component. [ka] In the formula (T), X represents a structure selected from the group consisting of the following (x-1) to (x-13):

[0045] [ka]

[0046] R 1 ~R 4 R each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, a monovalent organic group having 1 to 6 carbon atoms and containing a fluorine atom, or a phenyl group.5 and R 6 Each of j and k is independently a hydrogen atom or a methyl group. 1 and A 2 each independently represents a single bond, an ether (-O-), a carbonyl (-CO-), an ester (-COO- or -OCO-), a phenylene group, a sulfonyl group (-SO 2 In formula (x-13), two A's represent a bond to one acid anhydride group, and *2 represents a bond to the other acid anhydride group. 2 may be the same or different from each other.

[0047] More preferred specific examples of the above formula (x-1) include the following formulae (X1-1) to (X1-6), in which * represents a bond.

[0048] [ka]

[0049] Preferred specific examples of the above formulae (x-12) and (x-13) include the following formulae (x-14) to (x-29), in which * represents a bond. [ka] [ka]

[0050] Preferred specific examples of the tetracarboxylic dianhydride or derivative thereof represented by the above formula (T) include those in which X is selected from the above formulas (x-1) to (x-7) and (x-11) to (x-13).

[0051] The proportion of the tetracarboxylic dianhydride represented by the above formula (T) or a derivative thereof used is preferably 1 mol % or more, more preferably 5 mol % or more, and even more preferably 10 mol % or more, based on 1 mol of the total tetracarboxylic acid components used. The tetracarboxylic dianhydride and its derivatives used in the production of the polyamic acid (P) may contain a tetracarboxylic dianhydride or its derivative other than that of the above formula (T).

[0052] The polyamic acid (P) is produced by reacting the diamine component and the tetracarboxylic acid component in a solvent (condensation polymerization). The solvent is not particularly limited as long as the produced polymer is soluble in the solvent. Specific examples of the solvent include N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, γ-butyrolactone, N,N-dimethylformamide, N,N-dimethylacetamide, dimethylsulfoxide, 1,3-dimethyl-2-imidazolidinone, etc. In addition, when the polymer has high solubility in the 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.

[0053] [ka] (In formula [D-1], D 1 represents an alkyl group having 1 to 3 carbon atoms, and in formula [D-2], D 2 represents an alkyl group having 1 to 3 carbon atoms, and in formula [D-3], D 3 represents an alkyl group having 1 to 4 carbon atoms.

[0054] These solvents may be used alone or in combination. Furthermore, even if the solvent does not dissolve the polymer, it may be mixed with the above-mentioned solvent to the extent that the produced polymer does not precipitate. When the diamine component and the tetracarboxylic acid component are reacted in a solvent, the reaction can be carried out at any concentration, but the total amount of the diamine component and the tetracarboxylic acid component relative to the reaction solution is preferably 1 to 50% by mass, more preferably 5 to 30% by mass. The reaction can be carried out at a high concentration in the early stage, and then the solvent can be added. In the reaction, the ratio of the total number of moles of the diamine components to the total number of moles of the tetracarboxylic acid components is preferably 0.8 to 1.2. As in the case of a normal polycondensation reaction, the closer this molar ratio is to 1.0, the higher the molecular weight of the specific polymer produced.

[0055] The polyamic acid ester, which is a polyimide precursor, can be obtained by a known method such as, for example, [I] a method of reacting the polyamic acid obtained by the above synthesis reaction 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.

[0056] [Polyimide] The polyimide contained in the liquid crystal alignment agent of the present invention is a polyimide obtained by ring-closing the above-mentioned polyimide precursor. In the polyimide, the ring-closing rate of the amic acid group (also called the imidization rate) does not necessarily need to be 100%, and can be arbitrarily adjusted according to the application or purpose.

[0057] Methods for obtaining polyimide by imidizing a polyimide precursor include thermal imidization in which a solution of the polyimide precursor is heated as is, and catalytic imidization in which a catalyst is added to a solution of the polyimide precursor. When thermally imidizing a polyimide precursor in a solution, the temperature is 100 to 400°C, preferably 120 to 250°C, and it is preferable to carry out the thermal imidization while removing water generated by the imidization reaction from the system.

[0058] The catalytic imidization of the polyimide precursor can be carried out by adding a basic catalyst and an acid anhydride to a solution of the polyimide precursor and stirring at -20 to 250°C, preferably 0 to 180°C. The amount of the basic catalyst is 0.5 to 30 times by mole, preferably 2 to 20 times by mole, the amount of the acid anhydride is 1 to 50 times by mole, preferably 3 to 3 ...

[0059] When recovering the polyimide produced from the reaction solution of imidization of the polyimide precursor, the reaction solution may be poured into a solvent to cause precipitation. Examples of the solvent used for precipitation include methanol, ethanol, isopropyl alcohol, acetone, hexane, butyl cellosolve, heptane, methyl ethyl ketone, methyl isobutyl ketone, toluene, benzene, and water. The polymer precipitated by pouring into the solvent can be recovered by filtration, and then dried at room temperature or by heating under normal or reduced pressure. In addition, the polymer precipitated and recovered can be redissolved in a solvent and the reprecipitation and recovery operation can be repeated 2 to 10 times to reduce impurities in the polymer. Examples of the solvent in this case include alcohols and ketones, and the like. It is preferable to use three or more solvents selected from these because the efficiency of purification is further improved.

[0060] The polystyrene-equivalent weight average molecular weight (Mw) of the polyimide precursor and polyimide measured by gel permeation chromatography (GPC) is preferably 5,000 to 1,000,000, more preferably 10,000 to 150,000. The molecular weight distribution (Mw / Mn), which is expressed as the ratio of Mw to the polystyrene-equivalent number average molecular weight (Mn) measured by GPC, is preferably 15 or less, more preferably 10 or less. With the molecular weight in this range, good alignment properties of liquid crystal display elements can be ensured.

[0061] <End-capping agent> In synthesizing the polymer (P) of the present invention, a terminal-capping type polymer may be synthesized by using a suitable terminal-capping agent together with the above-mentioned tetracarboxylic acid component and diamine component. The terminal-capping type polymer has the effect of improving the film hardness of the liquid crystal alignment film obtained by coating and improving the adhesion property between the sealant and the liquid crystal alignment film. Examples of the terminals of the polymer (P) in the present invention include an amino group, a carboxy group, an acid anhydride group, an isocyanate group, or derivatives thereof. The above terminals can be obtained by a conventional condensation reaction or by blocking the terminals with the following terminal blocking agents.

[0062] 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, compounds represented by the following formulas (m-1) to (m-6), 3-(3-trimethoxysilyl)propyl)-3,4-dihydrofuran-2,5-dione, 4,5,6,7-tetrafluoroisobenzofuran-1,3-dione, and 4-ethynylphthalic anhydride; [ka] Examples of the dicarbonate diester compounds include di-tert-butyl dicarbonate and diallyl dicarbonate; chlorocarbonyl compounds include acryloyl chloride, methacryloyl chloride and nicotinic acid chloride; monoamine compounds include aniline, 2-aminophenol, 3-aminophenol, 4-aminosalicylic acid, 5-aminosalicylic acid, 6-aminosalicylic acid, 2-aminobenzoic acid, 3-aminobenzoic acid, 4-aminobenzoic acid, cyclohexylamine, n-butylamine, n-pentylamine, n-hexylamine, n-heptylamine and n-octylamine; and monoisocyanate compounds include ethyl isocyanate, phenyl isocyanate and naphthyl isocyanate.

[0063] The proportion of the end-capping agent used is preferably 0.01 to 20 parts by mol, and more preferably 0.01 to 10 parts by mol, based on 100 parts by mol of the total of the diamine components used.

[0064] The content of the polymer (P) in the liquid crystal aligning agent of the present invention is preferably 30 parts by mass or more, more preferably 30 to 100 parts by mass, and even more preferably 50 to 100 parts by mass, based on 100 parts by mass of the total of the polymers contained in the liquid crystal aligning agent.

[0065] (Other Ingredients) The liquid crystal aligning agent of the present invention is, for example, a liquid composition obtained by dispersing or dissolving the polymer (P) and other components used as necessary, preferably in a suitable solvent.

[0066] In the liquid crystal aligning agent of the present invention, in addition to the polymer (P), other polymers (hereinafter also referred to as other polymers) may be contained, for example, for the purpose of improving electrical properties, vertical alignment properties, and solution properties. The content of the 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, based on 100 parts by mass of the total of the polymers contained in the liquid crystal alignment agent.

[0067] The other polymer is not particularly limited, and examples thereof include the main skeleton of polysiloxane, polyester, polyamide, polyurea, polyorganosiloxane, cellulose derivative, polyacetal, polystyrene derivative, poly(styrene-phenylmaleimide) derivative, poly(meth)acrylate, etc. Among them, at least one selected from the group consisting of polyamide, polyurea, polyorganosiloxane, poly(meth)acrylate, and polyester is preferable. The other polymer may be used in combination of two or more kinds.

[0068] The liquid crystal aligning agent of the present invention may contain other components as necessary. Examples of the components include at least one compound selected from the group consisting of crosslinkable compounds having at least one substituent selected from epoxy groups, isocyanate groups, oxetane groups, cyclocarbonate groups, blocked isocyanate groups, hydroxyl groups, and alkoxy groups, and crosslinkable compounds having polymerizable unsaturated groups, functional silane compounds, metal chelate compounds, curing accelerators, surfactants, antioxidants, sensitizers, preservatives, and compounds for adjusting the dielectric constant and electrical resistance of the liquid crystal alignment film. Preferable specific examples of the crosslinkable compound include the compounds represented by the following formulas (CL-1) to (CL-11). [ka]

[0069] Compounds for adjusting the dielectric constant and electrical resistance of the liquid crystal alignment film include monoamines having a nitrogen-containing aromatic heterocycle such as 3-picolylamine. When using a monoamine having a nitrogen-containing aromatic heterocycle, the amount is preferably 0.1 to 30 parts by mass, more preferably 0.1 to 20 parts by mass, per 100 parts by mass of the polymer component contained in the liquid crystal alignment agent.

[0070] Preferred specific examples of the functional silane compound 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, vinyltrimethoxysilane, vinyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, Examples of the functional silane compound include 3-glycidoxypropyl trimethoxysilane, 3-glycidoxypropyl methyl diethoxysilane, 3-glycidoxypropyl triethoxysilane, p-styryl trimethoxysilane, 3-methacryloxypropyl methyl dimethoxysilane, 3-methacryloxypropyl trimethoxysilane, 3-methacryloxypropyl methyl diethoxysilane, 3-methacryloxypropyl triethoxysilane, 3-acryloxypropyl trimethoxysilane, tris-(trimethoxysilylpropyl)isocyanurate, 3-mercaptopropyl methyl dimethoxysilane, 3-mercaptopropyl trimethoxysilane, and 3-isocyanate propyl triethoxysilane. When a functional silane compound is used, it is preferably 0.1 to 30 parts by mass, more preferably 0.1 to 20 parts by mass, relative to 100 parts by mass of the polymer component contained in the liquid crystal alignment agent.

[0071] The organic solvent contained in the liquid crystal alignment agent is not particularly limited as long as the polymer component is uniformly dissolved in the organic solvent. Specific examples thereof include N,N-dimethylformamide, N,N-dimethylacetamide, N,N-dimethyllactamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, dimethylsulfoxide, γ-butyrolactone, γ-valerolactone, 1,3-dimethyl-2-imidazolidinone, methyl ethyl ketone, cyclohexanone, cyclopentanone, 3-methoxy-N,N-dimethylpropanamide, 3-butoxy-N,N-dimethylpropanamide, 3-methyl ... Examples of the good solvent include N-propanamide, 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, and N-cyclohexyl-2-pyrrolidone (collectively referred to as "good solvent"). Among these, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 3-methoxy-N,N-dimethylpropanamide, 3-butoxy-N,N-dimethylpropanamide, and γ-butyrolactone are preferred. The content of the good solvent is preferably 20 to 99% by mass, more preferably 20 to 90% by mass, and particularly preferably 30 to 80% by mass of the total solvent contained in the liquid crystal alignment agent.

[0072] In addition, the organic solvent contained in the liquid crystal alignment agent is preferably a mixed solvent containing the above-mentioned solvent and a solvent (also called a poor solvent) that improves the coating property when applying the liquid crystal alignment agent and the surface smoothness of the coating film. Specific examples of the organic solvent to be used in combination are shown below, but are not limited thereto.

[0073] For example, diisopropyl ether, diisobutyl ether, diisobutyl carbinol (2,6-dimethyl-4-heptanol), ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, 1,2-butoxyethane, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, 4-hydroxy-4-methyl-2-pentanone, diethylene glycol methyl ethyl ether, diethylene glycol dibutyl ether, 3-ethoxybutyl acetate, 1-methylpentyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, ethylene glycol monoacetate, ethylene glycol diacetate, propylene carbonate, ethylene carbonate, ethylene glycol monobutyl ether, ethylene glycol monoisoamyl ether, ethylene glycol monohexyl ether, propylene glycol monobutyl ether, 1-(2-butoxyethoxy)-2-propanol, propanol, 2-(2-butoxyethoxy)-1-propanol, propylene glycol monomethyl ether acetate, propylene glycol diacetate, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol dimethyl ether, ethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, 2-(2-ethoxyethoxy)ethyl acetate, diethylene glycol acetate, propylene glycol diacetate, n-butyl acetate, propylene glycol monoethyl ether acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, propyl 3-methoxypropionate, butyl 3-methoxypropionate, n-butyl lactate, isoamyl lactate, diethylene glycol monoethyl ether, diisobutyl ketone (2,6-dimethyl-4-heptanone), etc.

[0074] Of these, diisobutyl carbinol, propylene glycol monobutyl ether, propylene glycol diacetate, diethylene glycol diethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol dimethyl ether, 4-hydroxy-4-methyl-2-pentanone, ethylene glycol monobutyl ether, ethylene glycol monobutyl ether acetate, or diisobutyl ketone is preferred. The content of the poor solvent is preferably 1 to 80 mass % of the total solvent contained in the liquid crystal alignment agent, more preferably 10 to 80 mass %, particularly preferably 20 to 70 mass %. The type and content of the poor solvent are appropriately selected depending on the coating device, coating conditions, coating environment, etc. of the liquid crystal alignment agent.

[0075] Preferred combinations of good and poor solvents include N-methyl-2-pyrrolidone and ethylene glycol monobutyl ether, N-methyl-2-pyrrolidone, γ-butyrolactone and ethylene glycol monobutyl ether, N-methyl-2-pyrrolidone, γ-butyrolactone and propylene glycol monobutyl ether, N-ethyl-2-pyrrolidone and propylene glycol monobutyl ether, N-ethyl-2-pyrrolidone and 4-hydroxy-4-methyl-2-pentanone, N-ethyl-2-pyrrolidone and propylene glycol diacetate, and N,N-diphenyl ether. Methyl 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 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,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 diisopropyl ether butyl ketone, N-methyl-2-pyrrolidone, 4-hydroxy-4-methyl-2-pentanone and dipropylene glycol monomethyl ether, N-methyl-2-pyrrolidone, 4-hydroxy-4-methyl-2-pentanone and propylene glycol monobutyl ether, N-methyl-2-pyrrolidone, 4-hydroxy-4-methyl-2-pentanone and propylene glycol diacetate, γ-butyrolactone, 4-hydroxy-4-methyl-2-pentanone and diisobutyl ketone, γ-butyrolactone and 4-hydroxy-4-methyl-2-pentanone Tanone 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-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 γ-butyrolactone and dipropylene glycol dimethyl ether, N-methyl-2-pyrrolidone and γ-butyrolactone and dipropylene glycol dimethyl ether, N-ethyl-2-pyrrolidone, propylene glycol monobutyl ether, dipropylene glycol dimethyl ether, N-ethyl-2-pyrrolidone, propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, N-ethyl-2-pyrrolidone, propylene glycol monobutyl ether, propylene glycol diacetate, N-ethyl-2-pyrrolidone, propylene glycol monobutyl ether, diisobutyl ketone, N-ethyl-2-pyrrolidone, γ-butyrolactone, diisobutyl ketone, N-ethyl-2-pyrrolidone, N,Examples include N-dimethyl lactamide and diisobutyl ketone.

[0076] The solid content concentration in the liquid crystal alignment agent (the ratio of the total mass of the components other than the solvent of the liquid crystal alignment agent to the total mass of the liquid crystal alignment agent) is appropriately selected in consideration of viscosity, volatility, etc., and is preferably in the range of 1 to 10 mass%. The particularly preferable range of the solid content concentration varies depending on the method used to apply the liquid crystal alignment agent to the substrate. For example, in the case of the spinner method, the solid content concentration is particularly preferably in the range of 1.5 to 4.5 mass%. In the case of the printing method, it is particularly preferable to set the solid content concentration in the range of 3 to 9 mass%, thereby setting the solution viscosity in the range of 12 to 50 mPa·s. In the case of the inkjet method, it is particularly preferable to set the solid content concentration in the range of 1 to 5 mass%, thereby setting the solution viscosity in the range of 3 to 15 mPa·s.

[0077] (Liquid crystal alignment film / Liquid crystal display element) The liquid crystal alignment film of the present invention is obtained from the above liquid crystal alignment agent. The liquid crystal alignment film of the present invention can be used as a horizontal alignment type or vertical alignment type liquid crystal alignment film, and is particularly suitable for a vertical alignment type liquid crystal display element such as a VA mode or a PSA mode described later. The liquid crystal display element of the present invention is provided with the above liquid crystal alignment film. The liquid crystal display element of the present invention comprises the liquid crystal alignment film of the present invention. An example of the method for producing a liquid crystal display element of the present invention includes steps (A), (B), and (C). Step (A): A step of applying the liquid crystal aligning agent of the present invention onto a pair of substrates having a conductive film to form a coating film. Step (B): A step of forming a liquid crystal cell by arranging the coating films so that they face each other with a layer of liquid crystal molecules interposed between them. Step (C): A step of irradiating the liquid crystal cell with light while applying a voltage between the conductive films of the pair of substrates.

[0078] The liquid crystal display element of the present invention can be produced, for example, by a method including the following steps (1) to (3) or (1) to (4). (1) A process of applying a liquid crystal alignment agent onto a substrate The liquid crystal alignment agent of the present invention is applied to one side of a substrate on which a patterned transparent conductive film is provided by an appropriate application method such as a roll coater method, a spin coat method, a printing method, an inkjet method, etc. The substrate is not particularly limited as long as it is a highly transparent substrate, and plastic substrates such as acrylic substrates and polycarbonate substrates can be used in addition to glass substrates and silicon nitride substrates. In addition, in a reflective liquid crystal display element, an opaque material such as a silicon wafer can be used for only one substrate, and in this case, a light-reflecting material such as aluminum can be used for the electrode.

[0079] (2) The coating is baked After applying the liquid crystal alignment agent, preliminary heating (pre-baking) is preferably performed first for the purpose of preventing dripping of the applied alignment agent. The pre-baking temperature is preferably 30 to 200°C, more preferably 40 to 150°C, and particularly preferably 40 to 100°C. The pre-baking time is preferably 0.25 to 10 minutes, more preferably 0.5 to 5 minutes. Then, in order to evaporate the solvent, it is preferable to perform a further heating (post-baking) step. The post-baking temperature is preferably 80 to 300°C, more preferably 120 to 250°C. The post-baking time is preferably 5 to 200 minutes, more preferably 10 to 100 minutes. The film thickness of the film thus formed is preferably 5 to 300 nm, more preferably 10 to 200 nm.

[0080] The coating film formed in the above step (1) can be used as a liquid crystal alignment film as it is, but the coating film may be subjected to an alignment ability imparting treatment, such as a rubbing treatment in which the coating film is rubbed in a certain direction with a roll wrapped with a cloth made of fibers such as nylon, rayon, or cotton, or a photoalignment treatment in which the coating film is irradiated with polarized or non-polarized radiation.

[0081] In the photo-alignment treatment, the radiation to be irradiated to the coating film may be, for example, ultraviolet light and visible light containing light with a wavelength of 150 to 800 nm. When the radiation is polarized, it may be linearly polarized or partially polarized. When the radiation used is linearly polarized or partially polarized, the radiation may be applied from a direction perpendicular to the substrate surface, from an oblique direction, or a combination of these. When non-polarized radiation is applied, the radiation is applied in an oblique direction.

[0082] (3) Forming the liquid crystal layer (3-1) VA type LCD element Two substrates on which a liquid crystal alignment film is formed are prepared as described above, and liquid crystal is placed between the two substrates arranged opposite each other. Specifically, the following two methods can be mentioned. The first method is a conventionally known method. First, the two substrates are arranged opposite each other with a gap (cell gap) between them so that the liquid crystal alignment films face each other. Next, the peripheries of the two substrates are bonded together using a sealant, and a liquid crystal composition is injected and filled into the substrate surfaces and the cell gap partitioned by the sealant to come into contact with the film surface, and then the injection hole is sealed.

[0083] The second method is a method called ODF (One Drop Fill) method. For example, a UV-curable sealant is applied to a predetermined location on one of the two substrates on which a liquid crystal alignment film is formed, and a liquid crystal composition is dropped at a predetermined number of locations on the liquid crystal alignment film surface. Thereafter, the other substrate is bonded so that the liquid crystal alignment film faces the other substrate, and the liquid crystal composition is spread over the entire surface of the substrate and contacted with the film surface. Next, the entire surface of the substrate is irradiated with UV light to cure the sealant. In either method, it is preferable to further remove the flow alignment during liquid crystal filling by heating to a temperature at which the liquid crystal composition used has an isotropic phase and then slowly cooling to room temperature.

[0084] The liquid crystal aligning agent of the present invention is also preferably used for a liquid crystal display element (hereinafter, also referred to as a PSA type liquid crystal display element) which has a liquid crystal layer between a pair of substrates equipped with electrodes, and is manufactured through a process of disposing a liquid crystal composition containing a polymerizable compound which is polymerized by at least one of active energy rays and heat between the pair of substrates, and polymerizing the polymerizable compound by at least one of irradiation with active energy rays and heating while applying a voltage between the electrodes. The liquid crystal aligning agent of the present invention may also be used in a liquid crystal display element (hereinafter also referred to as an SC-PVA mode type liquid crystal display element) which has a liquid crystal layer between a pair of substrates equipped with electrodes, and is manufactured by disposing a liquid crystal alignment film between the pair of substrates, the liquid crystal alignment film including a polymerizable group that is polymerized by at least one of active energy rays and heat, and applying a voltage between the electrodes.

[0085] (3-2) Manufacturing of PSA type liquid crystal display elements The procedure is the same as that of (3-1) above, except that a liquid crystal composition containing a polymerizable compound is injected or dropped. Examples of the polymerizable compound include polymerizable compounds represented by the following formulas (M-1) to (M-7). [ka]

[0086] (3-3) Manufacturing of SC-PVA mode type liquid crystal display element A method of manufacturing a liquid crystal display element may be adopted in which, after the same procedure as in the above (3-1), a step of irradiating ultraviolet light described later is carried out. According to this method, a liquid crystal display element having excellent response speed can be obtained with a small amount of light irradiation, as in the case of manufacturing the above PSA type liquid crystal display element. The compound having a polymerizable group may be a compound having one or more polymerizable unsaturated groups in the molecule, such as acrylate groups or methacrylate groups, as represented by the above formulas (M-1) to (M-7), and the content thereof is preferably 0.1 to 30 parts by mass, more preferably 1 to 20 parts by mass, relative to 100 parts by mass of all polymer components. The polymerizable group may be contained in a polymer used for a liquid crystal alignment agent, and an example of such a polymer is a polymer obtained by using a diamine component containing a diamine having the above photopolymerizable group at its terminal in a reaction.

[0087] (4) UV irradiation process The liquid crystal cell is irradiated with light while a voltage is applied between the conductive films of the pair of substrates obtained in (3-2) or (3-3) above. The voltage applied here can be, for example, 5 to 50 V DC or AC. The light to be irradiated can be, for example, ultraviolet light and visible light containing light with a wavelength of 150 to 800 nm, but ultraviolet light containing light with a wavelength of 300 to 400 nm is preferred. The light source for the irradiation light can be, for example, a low-pressure mercury lamp, a high-pressure mercury lamp, a deuterium lamp, a metal halide lamp, an argon resonance lamp, a xenon lamp, an excimer laser, or the like. The light irradiation dose is preferably 1,000 to 200,000 J / m 2 and more preferably 1,000 to 100,000 J / m 2 It is.

[0088] A liquid crystal display element can be obtained by attaching a polarizing plate to the outer surface of the liquid crystal cell. Examples of the polarizing plate to be attached to the outer surface of the liquid crystal cell include a polarizing film called an "H film" made by absorbing iodine while stretching and aligning polyvinyl alcohol, sandwiched between cellulose acetate protective films, and a polarizing plate made of the H film itself.

[0089] The liquid crystal display element of the present invention can be effectively applied to various devices, and can be used in various display devices such as watches, portable games, word processors, notebook computers, car navigation systems, camcorders, PDAs, digital cameras, mobile phones, smartphones, various monitors, liquid crystal televisions, information displays, etc. The polymer composition contained in the liquid crystal alignment agent can also be used as a liquid crystal alignment film for a retardation film, a liquid crystal alignment film for a scanning antenna or a liquid crystal array antenna, or a liquid crystal alignment film for a transmissive scattering type liquid crystal light control element, or for other purposes such as a protective film for a color filter, a gate insulating film for a flexible display, or a substrate material. EXAMPLES

[0090] The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. The abbreviations of the compounds and the methods for measuring the respective properties are as follows.

[0091] (Tetracarboxylic acid dianhydride) DC-1 to DC-3: Compounds represented by the following formulas (DC-1) to (DC-3) [ka]

[0092] (Diamine) DA-1 to DA-11: Compounds represented by the following formulas (DA-1) to (DA-11). [ka]

[0093] The compound represented by formula (DA-1) was synthesized by the synthesis method described in a non-patent document (High Performance Polymers, vol. 31 (9-10), p. 1043-1053 (2019)). The compound represented by formula (DA-2) was synthesized by the synthesis method described in the non-patent document (Separation and Purification Technology, vol. 235, 116218 (2020)). The compound represented by formula (DA-3) was synthesized by the synthesis method described in the non-patent literature (Polymer Science, Series B: Polymer Chemistry, vol. 60(3), 273-282(2018)).

[0094] (solvent) NMP: N-methyl-2-pyrrolidone BCS: Butyl cellosolve (ethylene glycol monobutyl ether)

[0095] [viscosity] Measurements were performed using an E-type viscometer TVE-22H (manufactured by Toki Sangyo Co., Ltd.) with a sample amount of 1.1 mL (milliliters), a cone rotor TE-1 (1°34', R24), and a temperature of 25°C. [Molecular weight measurement] Measurements were carried out using a room temperature gel permeation chromatography (GPC) apparatus (GPC-101, Showa Denko KK) and columns (GPC KD-803, GPC KD-805, Showa Denko KK) as follows. Column temperature: 50℃ Eluent: N,N-dimethylformamide (with lithium bromide monohydrate (LiBr H 2 o) is 30mmol / L (liter), phosphoric acid anhydrous crystals (o-phosphoric acid) is 30mmol / L, and tetrahydrofuran (THF) is 10mL / L) Flow rate: 1.0mL / min Standard samples for preparing a calibration curve: TSK standard polyethylene oxide (molecular weight: approximately 900,000, 150,000, 100,000, and 30,000) (manufactured by Tosoh Corporation) and polyethylene glycol (molecular weight: approximately 12,000, 4,000, and 1,000) (manufactured by Polymer Laboratory Co., Ltd.).

[0096] [Synthesis of polyamic acid] <Synthesis Example 1> In a 100mL four-neck flask equipped with a stirrer, 2.05g (6.0mmol) of DA-1 and 2.80g (14.0mmol) of DA-7 were weighed out as diamine components, 19.4g of NMP was added, and the mixture was stirred to dissolve. While stirring this diamine solution, 4.26g (19.0mmol) of DC-1 as a tetracarboxylic dianhydride component was added, and then 17.0g of NMP was added. The mixture was stirred at 60℃ for 15 hours to obtain a solution of polyamic acid (A-1, viscosity: 625mPa s, number average molecular weight: 7,094).

[0097] <Synthesis Examples 2 to 7> Solutions of polyamic acids (A-2) to (A-7) shown in Table 1 were obtained by carrying out the same procedure as in Synthesis Example 1, except that the diamine component and the tetracarboxylic dianhydride component were changed to those shown in Table 1. The viscosity and molecular weight of the obtained polyamic acids are shown in Table 1.

[0098] [Table 1]

[0099] [Preparation of liquid crystal alignment agent] <Example 1> NMP (6.0 g) and BCS (8.0 g) were added to the solution (6.0 g) of polyamic acid (A-1) obtained above, and the mixture was stirred at room temperature for 10 hours to obtain a liquid crystal alignment agent (PAA-1) having a polyamic acid (A-1) concentration of 6 mass%, an NMP concentration of 54 mass%, and a BCS concentration of 40 mass% in the liquid crystal alignment agent.

[0100] <Examples 2 to 3, Comparative Examples 1 to 3, and Preparation Example 1> Except for changing the polyamic acid solution to that shown in Table 2 below, the same procedure as in Example 1 was carried out to obtain liquid crystal alignment agents (PAA-2) to (PAA-7) shown in Table 2 below.

[0101] [Table 2]

[0102] <Example 4> NMP (0.6 g) and BCS (1.4 g) were added to the liquid crystal alignment agent (PAA-1) (4.0 g) obtained above, and the mixture was stirred at room temperature for 10 hours to obtain a liquid crystal alignment agent (PAA-r-1) having a polyamic acid (A-1) concentration of 4 mass%, an NMP concentration of 46 mass%, and a BCS concentration of 50 mass% in the liquid crystal alignment agent.

[0103] <Examples 5 to 6 and Comparative Examples 4 to 6> Except for changing the polyamic acid solution to that shown in Table 3 below, the same procedure as in Example 4 was carried out to obtain liquid crystal alignment agents (PAA-r-2) to (PAA-r-6) shown in Table 3 below.

[0104] [Table 3]

[0105] <Examples 7 to 9 and Comparative Examples 7 to 9> The liquid crystal alignment agent (PAA-1) obtained in Example 1 and the liquid crystal alignment agent (PAA-7) obtained in Preparation Example 1 were mixed in a mass ratio of 3:7 (PAA-7:PAA-1), and stirred at room temperature for 3 hours to prepare the liquid crystal alignment agent (PAA-b-1) of Example 7. In addition, the liquid crystal alignment agents (PAA-b-2) to (PAA-b-6) of Examples 8 to 9 and Comparative Examples 7 to 9 shown in Table 4 below were prepared by carrying out the same procedure as in Example 7 except that the combination of liquid crystal alignment agents used was changed to that shown in Table 4 below.

[0106] [Table 4]

[0107] [Solubility of liquid crystal alignment agent in poor solvent] The liquid crystal alignment agents prepared in the above Examples 4 to 6 and Comparative Examples 4 to 6 were left to stand in a freezer at -20°C for 14 hours. After that, they were taken out to room temperature and visually confirmed whether the polymer solid matter had precipitated. The results are shown in Table 5. The case where the polymer had dissolved was marked with "◯", and the case where the polymer had precipitated was marked with "X".

[0108] [Table 5]

[0109] [Measurement of refractive index of liquid crystal alignment film] The liquid crystal alignment agent prepared in the above Examples 1 to 3 and Comparative Examples 1 to 3 was spin-coated on a silicon wafer, dried on a hot plate at 70°C for 90 seconds, and then baked in a hot air circulation oven at 230°C for 20 minutes to form a liquid crystal alignment film with a thickness of 100 nm. Next, a spectroscopic ellipsometer (M-2000, manufactured by JA Woollam Co., Ltd.) was used to measure the refractive index at wavelengths of 250 to 800 nm by fitting using the CAUCHY model. The results are shown in Table 6. Table 6 lists the refractive index at a wavelength of 550 nm. A refractive index of 1.630 or more was rated as "excellent," and a refractive index of less than 1.630 was rated as "unacceptable."

[0110] [Table 6]

[0111] [Preparation of liquid crystal alignment film and liquid crystal cell] Using the liquid crystal alignment agents prepared in the above Examples 7 to 9 and Comparative Examples 7 to 9, liquid crystal cells were produced as follows. Each liquid crystal alignment agent was spin-coated onto the ITO surface of an ITO electrode substrate on which an ITO electrode pattern with a pixel size of 100 μm × 300 μm and a line / space of 5 μm each was formed, and then dried on a hot plate at 70°C for 90 seconds and baked in a hot air circulating oven at 230°C for 30 minutes to form a liquid crystal alignment film with a thickness of 100 nm. In addition, a liquid crystal alignment agent was spin-coated onto the ITO surface on which no electrode pattern was formed, and the surface was dried on a hot plate at 70°C for 90 seconds. After that, the surface was baked in a hot air circulating oven at 230°C for 20 minutes to form a liquid crystal alignment film with a thickness of 100 nm. For the two substrates described above, 4 μm bead spacers were sprayed on the liquid crystal alignment film of one substrate, and then a sealant (solvent-based thermosetting epoxy resin) was printed on top of the bead spacers. Next, the other substrate was attached to the previous substrate with the side on which the liquid crystal alignment film was formed facing inward, and the sealant was thermally cured to prepare an empty cell. Liquid crystal containing a polymerizable compound (MLC-3023, Merck) was injected into this empty cell by the reduced pressure injection method to prepare a liquid crystal cell. After that, a DC voltage of 15 V was applied to the liquid crystal cell, and ultraviolet light was applied from the outside of the liquid crystal cell at 10 J / cm through a filter that cuts off wavelengths of 325 nm or less. 2 The illuminance of the ultraviolet light was measured using a UV-MO3A manufactured by ORC Corp. After that, in order to inactivate the unreacted polymerizable compound remaining in the liquid crystal cell, the cell was irradiated with ultraviolet light (UV lamp: FLR40SUV32 / A-1) for 30 minutes using a UV-FL irradiation device (manufactured by Toshiba Lighting & Technology Corp.) in a state where no voltage was applied.

[0112] [Evaluation of vertical alignment] The evaluation of the vertical alignment of each liquid crystal cell prepared as described above is shown in Table 7. The evaluation method is as follows. Each liquid crystal cell was sandwiched between crossed Nicol polarizers and irradiated from behind with a backlight, and the liquid crystal cell was rotated and visually observed to see whether the liquid crystal was vertically aligned based on the change in light and dark. The evaluation criteria were "Good" if the liquid crystal was vertically aligned and "Poor" if the liquid crystal was not vertically aligned. The results are shown in Table 7.

[0113] [Table 7]

Claims

1. A liquid crystal alignment agent for vertical alignment, comprising a polymer (P) containing at least one selected from the group consisting of a polyimide precursor and a polyimide obtained using a diamine component containing a diamine (1) represented by the following formula (1): 【Chemistry 1】 (Ar represents a phenylene group, Q represents a divalent organic group containing at least one naphthalene ring, Q and each of the two oxygen atoms are bonded on a benzene ring constituting the at least one naphthalene ring, and the benzene ring bonded to one oxygen atom is different from the benzene ring bonded to the other oxygen atom. Any hydrogen atom on the phenylene group may be substituted with at least one selected from the group consisting of an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a fluorine-containing alkyl group having 1 to 3 carbon atoms, a fluorine-containing alkoxy group having 1 to 3 carbon atoms, and a fluorine atom.)

2. 2. The liquid crystal aligning agent for vertical alignment according to claim 1, wherein Q represents a divalent organic group having 10 to 40 carbon atoms and represented by the following formula (f): 【Chemistry 2】 (A １ and A ２ Each of X is independently a naphthalene ring which may have a substituent. １ and X ２ are each independently a single bond, an oxygen atom, or a sulfur atom. Y is an alkylene group having 1 to 8 carbon atoms, or a divalent organic group containing an oxygen atom or a sulfur atom between the carbon-carbon bonds of an alkylene group having 1 to 8 carbon atoms. m is an integer of 0 to 2, and n is an integer of 0 or 1. * represents a bond.

3. The liquid crystal aligning agent for vertical alignment according to claim 1 or 2, wherein the diamine (1) is any diamine selected from the group consisting of the following formulas (d-1) to (d-2): 【Chemistry 3】

4. The polymer (P) contains, as a constituent, at least one diamine (s) having a partial structure represented by the following formulas (S1) to (S3): The liquid crystal alignment agent for vertical alignment according to any one of claims 1 to 3. 【Chemistry 4】 (X １ and X ２ each independently represents a single bond, -(CH ２ ) ａ -(a is an integer of 1 to 15), -CONH-, -NHCO-, -CON(CH ３ ) -, -N(CH ３ )CO-, -NH-, -O-, -COO-, -OCO-, -((CH ２ ) ａ１ -A １ ) ｍ１ - or - (A １ - (CH ２ ) ａ１ ) ｍ１ - [a1 is an integer from 1 to 15, A １ represents an oxygen atom, -COO-, or -OCO-, and m1 is an integer of 1 to 2. When m1 is 2, each of the multiple a1's is independent, and １ are each independent. １ and G ２ each independently represents a divalent cyclic group selected from a divalent aromatic group having 6 to 12 carbon atoms and a divalent alicyclic group having 3 to 8 carbon atoms. Any hydrogen atom on the cyclic group may be substituted with at least one selected from the group consisting of an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a fluorine-containing alkyl group having 1 to 3 carbon atoms, a fluorine-containing alkoxy group having 1 to 3 carbon atoms, and a fluorine atom. m and n are each independently an integer of 0 to 3, and the sum of m and n is 1 to 6. R １ 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; R １ Any hydrogen atom forming the formula (I) may be substituted with a fluorine atom. 【Chemistry 5】 (X ３ represents a single bond, -CONH-, -NHCO-, -CON(CH ３ ) -, -N(CH ３ )CO-, -NH-, -O-, -CH ２ represents -O-, -COO- or -OCO-. ２ represents an alkyl group having 1 to 20 carbon atoms or an alkoxyalkyl group having 2 to 20 carbon atoms; R ２ Any hydrogen atom forming the formula (I) may be substituted with a fluorine atom. 【Chemistry 6】 (X ４ -CONH-, -NHCO-, -O-, -COO-, -OCO-, -((CH ２ ) ａ１ -A １ ) ｍ１ - or - (A １ - (CH ２ ) ａ１ ) ｍ１ - [a1 is an integer from 1 to 15, A １ represents an oxygen atom, -COO-, or -OCO-, and m1 is an integer of 1 to 2. When m1 is 2, each of the multiple a1's is independent, and １ are each independent. ３ represents a structure having a steroid skeleton.)

5. The liquid crystal aligning agent for vertical alignment according to claim 4 , wherein the diamine (s) is a diamine represented by the following formula (d1) or formula (d2): 【Chemistry 7】 (X is a single bond, —O—, —C(CH ３ ) ２ -, -NH-, -CO-, -COO-, -CONH-, -(CH ２ ) ｍ -, -SO ２ -, -O-(CH ２ ) ｍ -O-, -OC(CH ３ ) ２ --, --CO--(CH ２ ) ｍ --, --CO-(CH ２ ) ｍ -CO-, -NH-(CH ２ ) ｍ -, -NH-(CH ２ ) ｍ -NH-, -SO ２ - (CH ２ ) ｍ -, -SO ２ - (CH ２ ) ｍ -SO ２ -, -CONH-(CH ２ ) ｍ -, -CONH-(CH ２ ) ｍ -NHCO- or -COO-(CH ２ ) ｍ represents —OCO—; m is an integer of 1 to 8; and each Y independently represents a partial structure of any one of the formulae (S1) to (S3).

6. The liquid crystal aligning agent for vertical alignment according to claim 5, wherein the diamine represented by the formula (d1) is any diamine selected from the group consisting of the following formulas (d1-1) to (d1-18): 【Chemistry 8】 (n is an integer from 1 to 20.) 【Chemistry 9】

7. The liquid crystal aligning agent for vertical alignment according to claim 5, wherein the diamine represented by the formula (d2) is any diamine selected from the group consisting of the following formulas (d2-1) to (d2-6): 【Chemistry 10】 (X ｐ１ ~X ｐ８ is -(CH ２ ) ａ -(a is an integer of 1 to 15), -CONH-, -NHCO-, -CON(CH ３ )-, -NH-, -O-, -CH ２ O-, -CH ２ represents -OCO-, -COO-, or -OCO-; ｓ１ ~X ｓ４ Each independently represents -O-, -COO- or -OCO-. ａ ~X ｆ is a single bond, —O—, —NH—, or —O—(CH ２ ) ｍ -O- (where m is an integer of 1 to 8). １ａ ~R １ｈ 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.

8. The polymer (P) contains a tetracarboxylic acid component containing a tetracarboxylic dianhydride represented by the following formula (T) as a constituent component. The liquid crystal alignment agent for vertical alignment according to any one of claims 1 to 7. 【Chemistry 11】 (X represents a structure selected from the following (x-1) to (x-13).) 【Chemistry 12】 (R １ ~R ４ R 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 containing a fluorine atom, or a phenyl group. ５ and R ６ Each of j and k is independently a hydrogen atom or a methyl group. １ and A ２ each independently represents a single bond, an ether (-O-), a carbonyl (-CO-), an ester (-COO- or -OCO-), a phenylene group, a sulfonyl group (-SO ２ In the formula (x-13), two A's each represent an amide group (-CONH- or -NHCO-). *1 represents a bond bonded to one acid anhydride group, and *2 represents a bond bonded to the other acid anhydride group. ２ may be the same or different.)

9. The liquid crystal aligning agent for vertical alignment according to claim 8, wherein X in the formula (T) is any one of (x-1) to (x-7) and (x-11) to (x-13).

10. The liquid crystal aligning agent for vertical alignment according to any one of claims 1 to 9, wherein the diamine (1) is contained in an amount of 1 to 100 mol % in the total diamine components of the polymer (P).

11. The liquid crystal aligning agent for vertical alignment according to any one of claims 4 to 9, wherein the diamine (s) is contained in an amount of 1 to 99 mol % in the total diamine components of the polymer (P).

12. A liquid crystal alignment film for vertical alignment, formed by using the liquid crystal aligning agent for vertical alignment according to any one of claims 1 to 11.

13. A vertical alignment type liquid crystal display element comprising the liquid crystal alignment film for vertical alignment according to claim 11.

14. A method for producing a vertical alignment type liquid crystal display element, comprising the following steps (A), (B), and (C): Step (A): A step of applying the liquid crystal alignment agent for vertical alignment according to any one of claims 1 to 11 onto a pair of substrates having a conductive film to form a coating film. Step (B): A step of forming a liquid crystal cell by arranging the coating films so as to face each other with a layer of liquid crystal molecules interposed therebetween. Step (C): Irradiating the liquid crystal cell with light while applying a voltage between the conductive films of the pair of substrates.

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