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

Abstract

To provide a liquid crystal alignment agent that has excellent liquid crystal aligning properties and can give a liquid crystal element having excellent voltage holding properties and showing little deterioration of display quality after receiving external force.SOLUTION: A liquid crystal alignment agent contains a polymer [A] having a moiety (a) represented by formula (1) in the main chain. In formula (1), R1 and R2 each denote -C(R5)(R6)-, -O-, -S-, -CO-, -COO-, -NR7-, -NR7-NR8-, -NR7-CO-O-, -NR7-CO-NR8-, an aromatic hydrocarbon ring, a heteroaromatic ring or a nitrogen-containing non-heteroaromatic ring, which is a divalent group binding to a carbonyl group in formula (1). R3 and R4 each denote a hydrogen atom, a halogen atom or a C1-3 alkyl group, or R3 and R4 are taken together to form a ring structure.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a liquid crystal alignment agent, a liquid crystal alignment film, and a liquid crystal element. and polymerization On the body Regarding. [Background technology]

[0002] Conventionally, various driving methods have been developed for liquid crystal elements, differing in electrode structure and physical properties of the liquid crystal molecules used, including various types of liquid crystal elements such as TN type, STN type, VA type, MVA type, in-plane switching type (IPS type), FFS type, and optically compensated bend type (OCB type). These liquid crystal elements have a liquid crystal alignment film for aligning the liquid crystal molecules. A liquid crystal alignment film is generally formed on a substrate by applying a liquid crystal alignment agent, which is made by dissolving or dispersing a polymer component in an organic solvent, to the substrate surface and preferably by heating.

[0003] In recent years, large-screen, high-definition LCD televisions have become mainstream, and small display terminals such as smartphones and tablet PCs have become increasingly popular, further increasing the demand for higher quality liquid crystal elements. In order to meet this demand for higher quality, various liquid crystal alignment agents have been proposed (see, for example, Patent Document 1). Patent Document 1 discloses that a crosslinkable compound is contained in the liquid crystal alignment agent as a low-molecular compound that improves the hardness of the liquid crystal alignment film, together with a polyimide or a polyimide precursor. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2020 / 171128 Summary of the Invention [Problem to be solved by the invention]

[0005] As the resolution of liquid crystal elements increases, quality requirements become more stringent. For example, liquid crystal elements are required not only to further improve the liquid crystal alignment and voltage holding ratio, but also to withstand physical pressures such as vibrations and tapping during transportation. In particular, glass panels, which serve as the base material for liquid crystal elements, are becoming thinner, and the physical pressure applied to internal components is increasing. On the other hand, it is becoming difficult to maintain display quality simply by adding a crosslinking compound, as in the past.

[0006] The present invention has been made in consideration of the above-mentioned problems, and has as its main object to provide a liquid crystal alignment agent that can provide a liquid crystal element that has good liquid crystal alignment properties, excellent voltage retention characteristics, and suppresses deterioration in display quality due to exposure to external force. [Means for solving the problem]

[0007] The present inventors have conducted extensive research to solve the above problems and have found that the above problems can be solved by using a polymer having a specific carbon-carbon unsaturated structure, thereby completing the present invention. Specifically, the present invention provides the following means.

[0008] <1> A liquid crystal aligning agent comprising a polymer [A] having a partial structure (a) represented by the following formula (1) in its main chain: [ka] (In formula (1), R 1 and R 2 are each independently -C(R 5 )(R 6 )-, -O-, -S-, -CO-, -COO-, -NR 7 -, -NR 7 -NR 8 -, -NR 7 -CO-O-, -NR 7 -CO-NR 8 R is a divalent group that is an aromatic hydrocarbon ring, an aromatic heterocycle, or a nitrogen-containing non-aromatic heterocycle and is bonded to the carbonyl group in formula (1). 3 and R 4are each independently a hydrogen atom, a halogen atom, or an alkyl group having 1 to 3 carbon atoms, or R 3 and R 4 and are combined together, R 3 The carbon to which R is bonded 4 represents a ring structure formed together with the carbon to which R is attached. 5 and R 6 are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 8 carbon atoms, an alkenyl group having 1 to 8 carbon atoms, or an alkoxy group having 1 to 8 carbon atoms. 7 and R 8 are each independently a hydrogen atom or a monovalent organic group. "*" represents a bond.

[0009] <2> the above <1> A liquid crystal alignment film formed using the liquid crystal alignment agent of the above. <3> the above <2> A liquid crystal element comprising the liquid crystal alignment film. <4> A polyamic acid, a polyamic acid ester, or a polyimide having a partial structure represented by the above formula (1) in the main chain.

[0010] <5> A method for producing a diamine, comprising producing a diamine represented by the following formula (2) using a compound represented by the following formula (5) as a raw material. [ka] (In formula (5), R 9 is a single bond or a divalent organic group. [ka] (In formula (2), A 1 and A 2 R are each independently a single bond, a divalent alicyclic group, or a divalent aromatic ring group. 1 and R 2 are each independently -C(R 5 )(R 6 )-, -O-, -S-, -CO-, -COO-, -NR 7 -, -NR 7 -NR 8 -, -NR 7-CO-O-, -NR 7 -CO-NR 8 R is a divalent organic group that is an aromatic hydrocarbon ring, an aromatic heterocycle, or a nitrogen-containing non-aromatic heterocycle and is bonded to the carbonyl group in formula (2). 3 and R 4 are each independently a hydrogen atom, a halogen atom, or an alkyl group having 1 to 3 carbon atoms, or R 3 and R 4 and are combined together, R 3 The carbon to which R is bonded 4 represents a ring structure formed together with the carbon to which R is attached. 5 and R 6 are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 8 carbon atoms, an alkenyl group having 1 to 8 carbon atoms, or an alkoxy group having 1 to 8 carbon atoms. 7 and R 8 are each independently a hydrogen atom or a monovalent organic group. m1 is an integer of 1 to 3. When m1 is 2 or 3, multiple R 1 ~R 4 are the same or different from each other.)

[0011] <6> A method for producing a tetracarboxylic dianhydride, which comprises using the compound represented by the above formula (5) as a raw material to produce tetracarboxylic dianhydrides represented by the following formulas (3) and (4): [ka] (In formula (3) and formula (4), A 3 and A 4 are each independently a trivalent aromatic ring group or an aliphatic ring group. 1 and R 2 are each independently -C(R 5 )(R 6 )-, -O-, -S-, -CO-, -COO-, -NR 7 -, -NR 7 -NR 8 -, -NR 7 -CO-O-, -NR 7 -CO-NR 8R is a divalent organic group that is an aromatic hydrocarbon ring, an aromatic heterocycle, or a nitrogen-containing non-aromatic heterocycle and is bonded to the carbonyl group in formula (3) and formula (4). 3 and R 4 are each independently a hydrogen atom, a halogen atom, or an alkyl group having 1 to 3 carbon atoms, or R 3 and R 4 and are combined together, R 3 The carbon to which R is bonded 4 represents a ring structure formed together with the carbon to which R is attached. 5 and R 6 are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 8 carbon atoms, an alkenyl group having 1 to 8 carbon atoms, or an alkoxy group having 1 to 8 carbon atoms. 7 and R 8 are each independently a hydrogen atom or a monovalent organic group. m2 is an integer of 1 to 3. n1 and n2 are each independently an integer of 1 to 3. When m2 is 2 or 3, multiple R 1 ~R 4 are the same or different from each other.)

[0012] <7> the above <5> The diamine obtained by the method for producing <6> The above-mentioned tetracarboxylic acid dianhydride is obtained by polymerization using a monomer containing at least one compound selected from the group consisting of tetracarboxylic acid dianhydrides obtained by the production method of <4> The present invention relates to a method for producing a polymer, which comprises producing a polyamic acid, a polyamic acid ester, and a polyimide. [Effects of the Invention]

[0013] According to the liquid crystal aligning agent of the present invention, it is possible to obtain a liquid crystal element that has good liquid crystal alignment properties, excellent voltage retention characteristics, and suppresses deterioration in display quality even when subjected to external force (e.g., external force due to vibration, tapping, etc.). DETAILED DESCRIPTION OF THE INVENTION

[0014] Liquid crystal alignment agent Hereinafter, each component contained in the liquid crystal aligning agent of the present disclosure and other components that may be arbitrarily blended as necessary will be described.

[0015] In this specification, the term "hydrocarbon group" includes chain hydrocarbon groups, alicyclic hydrocarbon groups, and aromatic hydrocarbon groups. "Chain hydrocarbon group" refers to a straight-chain hydrocarbon group or a branched hydrocarbon group that does not contain a cyclic structure in the main chain and is composed only of a chain structure. However, it may be saturated or unsaturated. "Alicyclic hydrocarbon group" refers to a hydrocarbon group that contains only an alicyclic hydrocarbon structure as a ring structure and does not contain an aromatic ring structure. However, it does not have to be composed only of an alicyclic hydrocarbon structure and may also include one that has a chain structure as part of it. "Aromatic hydrocarbon group" refers to a hydrocarbon group that contains an aromatic ring structure as a ring structure. However, it does not have to be composed only of an aromatic ring structure and may contain a chain structure or an alicyclic hydrocarbon structure as part of it.

[0016] "Main chain" refers to the longest "trunk" part of the atomic chain of a polymer. It is permissible for this "trunk" part to contain a ring structure. "Side chain" refers to the part branched from the "trunk" of a polymer. "Aromatic ring" includes aromatic hydrocarbon rings and aromatic heterocycles. "Organic group" refers to an atomic group formed by removing any hydrogen atom from a compound containing carbon (i.e., an organic compound). "Tetracarboxylic acid derivative" includes tetracarboxylic acid dianhydrides, tetracarboxylic acid diesters, and tetracarboxylic acid diester dihalides.

[0017] The liquid crystal aligning agent of the present disclosure contains a polymer [A] having a partial structure (a) represented by the following formula (1) in the main chain. [ka] (In formula (1), R 1 and R 2 are each independently -C(R 5 )(R 6 )-, -O-, -S-, -CO-, -COO-, -NR 7 -, -NR 7 -NR 8 -, -NR 7 -CO-O-, -NR 7-CO-NR 8 R is a divalent group that is an aromatic hydrocarbon ring, an aromatic heterocycle, or a nitrogen-containing non-aromatic heterocycle and is bonded to the carbonyl group in formula (1). 3 and R 4 are each independently a hydrogen atom, a halogen atom, or an alkyl group having 1 to 3 carbon atoms, or R 3 and R 4 and are combined together, R 3 The carbon to which R is bonded 4 represents a ring structure formed together with the carbon to which R is attached. 5 and R 6 are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 8 carbon atoms, an alkenyl group having 1 to 8 carbon atoms, or an alkoxy group having 1 to 8 carbon atoms. 7 and R 8 are each independently a hydrogen atom or a monovalent organic group. "*" represents a bond.

[0018] <Polymer [A]> Regarding the partial structure (a) R in the above formula (1) 1 and R 2 -C(R 5 )(R 6 )- is a divalent group bonded to the carbonyl group in the above formula (1), R 5 and R 6 The alkyl group having 1 to 8 carbon atoms, the alkenyl group having 1 to 8 carbon atoms, and the alkoxy group having 1 to 8 carbon atoms represented by the formula (R) may be either linear or branched. 5 and R 6 Among these, a hydrogen atom or an alkyl group having 1 to 3 carbon atoms is preferred, and a hydrogen atom (i.e., -C(R 5 )(R 6 It is more preferred that )- is a methylene group.

[0019] R in the above formula (1) 1 and R 2 Ga-NR 7 -, -NR 7 -NR 8 -, -NR 7 -CO-O- and -NR 7-CO-NR 8 - is a divalent group bonded to the carbonyl group in the above formula (1), R 7 and R 8 The monovalent organic group represented by the formula (I) is preferably a monovalent hydrocarbon group having 1 to 10 carbon atoms, or a monovalent leaving group that is released by heat or light (hereinafter simply referred to as "leaving group").

[0020] R 7 and R 8 When the monovalent organic group represented by the formula (I) is a monovalent hydrocarbon group, specific examples of the hydrocarbon group include an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 4 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, and an aralkyl group having 6 to 10 carbon atoms. Of these, an alkyl group having 1 to 3 carbon atoms and a phenyl group are preferred, and an alkyl group having 1 to 3 carbon atoms is more preferred.

[0021] R 7 and R 8 When the monovalent organic group represented by the formula (I) is a monovalent leaving group, the leaving group is preferably a thermally leaving group that is released by heat (preferably by heating during film formation). Specific examples of thermally leaving groups include a tert-butoxycarbonyl group (Boc group), a benzyloxycarbonyl group, a 1,1-dimethyl-2-haloethyloxycarbonyl group, an allyloxycarbonyl group, and a 2-(trimethylsilyl)ethoxycarbonyl group. Among these, the Boc group is particularly preferred because it has excellent thermal release properties and can reduce the amount of the released structure remaining in the film.

[0022] R 7 and R 8 Among these, is preferably a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or a monovalent thermally detachable group, and more preferably a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or a tert-butoxycarbonyl group.

[0023] R 1 and R 2When is an aromatic hydrocarbon ring, an aromatic heterocycle, or a nitrogen-containing non-aromatic heterocycle that is bonded to the carbonyl group in the above formula (1), examples of the aromatic hydrocarbon ring include a benzene ring, a naphthalene ring, and an anthracene ring. Examples of the aromatic heterocycle include a nitrogen-containing aromatic heterocycle, an oxygen-containing aromatic heterocycle, and a sulfur-containing aromatic heterocycle. Specific examples of these include a pyridine ring, a pyrimidine ring, a pyridazine ring, and a pyrazine ring as the nitrogen-containing aromatic heterocycle; a furan ring as the oxygen-containing aromatic heterocycle; and a thiophene ring as the sulfur-containing aromatic heterocycle. Examples of the nitrogen-containing non-aromatic heterocycle include a piperidine ring and a piperazine ring. These rings may have a substituent. Examples of the substituent include an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a halogen atom, a hydrogen atom, and a cyano group.

[0024] R 1 and R 2 is -C(R 5 )(R 6 )-, -O-, -S-, -CO-, -COO-, -NR 7 -, -NR 7 -NR 8 -, -NR 7 -CO-O-, -NR 7 -CO-NR 8 The structure of the other portions is not particularly limited as long as it is a group that is bonded to the carbonyl group in formula (1) by an aromatic hydrocarbon ring, an aromatic heterocycle, or a nitrogen-containing non-aromatic heterocycle. 1 and R 2 When is bonded to the carbonyl group in the above formula (1) by -COO-, R 1 and R 2 may be bonded to the carbonyl group in the above formula (1) via an oxygen atom or a carbon atom. 1 and R 2 Ga-NR 7 When bonded to the carbonyl group in the above formula (1) via -CO-O-, R 1 and R 2may be bonded to the carbonyl group in the above formula (1) via a nitrogen atom or a carbon atom.

[0025] R 1 and R 2 A specific example of -C(R 5 )(R 6 )-, -O-, -S-, -CO-, -COO-, -NR 7 -, -NR 7 -NR 8 -, -NR 7 -CO-O-, -NR 7 -CO-NR 8 -, a divalent chain hydrocarbon group, a divalent aromatic hydrocarbon ring group, a divalent aromatic heterocyclic group, and a divalent nitrogen-containing non-aromatic heterocyclic group. 1 and R 2 represents -O-, -S-, -CO-, -COO-, -NR-, provided that the methylene groups of the divalent hydrocarbon group are not adjacent to each other. 7 -, -NR 7 -NR 8 -, -NR 7 -CO-O-, -NR 7 -CO-NR 8 or a divalent organic group substituted with a heterocyclic group.

[0026] R is a key technology in that it can increase the voltage holding ratio (VHR) of liquid crystal elements, can provide highly reliable liquid crystal elements with little decrease in voltage holding ratio even when driven for a long period of time, can provide liquid crystal elements that exhibit good liquid crystal alignment, and is highly effective in preventing deterioration of display quality due to vibration or tapping. 1 and R 2 Preferably, one or both of R are groups having a chain hydrocarbon structure with one or more carbon atoms, or divalent nitrogen-containing non-aromatic heterocyclic groups. 1 and R 2 or both of the above are divalent chain hydrocarbon groups having one or more carbon atoms, or -O-, -S-, -CO-, -COO-, -NR-, or -COO-, provided that any methylene groups possessed by the chain hydrocarbon groups having two or more carbon atoms are not adjacent to each other. 7 -, -NR 7 -NR8 -, -NR 7 -CO-O- or -NR 7 -CO-NR 8 -(wherein -C(R 5 )(R 6 )-, -O-, -S-, -CO-, -COO-, -NR 7 -, -NR 7 -NR 8 -, -NR 7 -CO-O- or -NR 7 -CO-NR 8 - which is bonded to the carbonyl group in the above formula (1)) or a divalent nitrogen-containing non-aromatic heterocyclic group. 1 and R 2 or both of the above are divalent chain hydrocarbon groups having one or more carbon atoms, or -O-, -S-, -CO-, -COO-, -NR 7 -, -NR 7 -NR 8 -, -NR 7 -CO-O- or -NR 7 -CO-NR 8 It is particularly preferable that R is a divalent group substituted with -. 5 , R 6 , R 7 and R 8 The above explanations can be applied to specific and preferred examples.

[0027] R 1 , R 2 When R is a divalent chain hydrocarbon group, the chain hydrocarbon group may be saturated or unsaturated, and may be linear or branched. R is a preferred compound in the following points: it can increase the voltage holding ratio of a liquid crystal device; it can provide a highly reliable liquid crystal device with little decrease in voltage holding ratio even when driven for a long period of time; it can provide a liquid crystal device that exhibits good liquid crystal alignment; and it can suppress deterioration of display quality due to vibration or tapping. 1 , R 2 The chain hydrocarbon group represented by R is preferably an alkanediyl group, more preferably a linear alkanediyl group.1 , R 2 When R is a divalent chain hydrocarbon group, the number of carbon atoms in the chain hydrocarbon group is preferably 2 or more, more preferably 3 or more, from the viewpoint of obtaining a liquid crystal element exhibiting a high voltage holding ratio and a liquid crystal element exhibiting good liquid crystal alignment. In addition, from the viewpoint of achieving both an improvement in film strength (and thus an improvement in rubbing resistance) and an improvement in the voltage holding ratio of the liquid crystal element, 1 , R 2 is a chain hydrocarbon group, R 1 , R 2 The number of carbon atoms is preferably 20 or less, more preferably 15 or less, and even more preferably 10 or less.

[0028] R 1 , R 2 However, -O-, -S-, -CO-, -COO-, -NR- ...O-, -S-, -CO-, -COO-, -O-, -S- 7 -, -NR 7 -NR 8 -, -NR 7 -CO-O- or -NR 7 -CO-NR 8 - (hereinafter also referred to as "divalent group A"), R 1 and R 2 One or both of the above is preferably a group represented by the following formula (6). -R 10 -X 1 -* 1 …(6) (In formula (6), R 10 is an alkanediyl group. X 1 -O-, -S-, -CO-, -COO-, -NR 7 -, -NR 7 -NR 8 -, -NR 7 -CO-O- or -NR 7 -CO-NR 8 -It is. 1 " represents a bond bonded to the carbonyl group in formula (1). 7 and R 8 is the same as formula (1).

[0029] In the above formula (6), R 10 The alkanediyl group represented by the following formula is preferably linear. The number of carbon atoms in the alkanediyl group is preferably 1 to 10, more preferably 2 to 10, and even more preferably 2 to 5.

[0030] R 1 and R 2 When is a divalent nitrogen-containing non-aromatic heterocyclic group, the divalent nitrogen-containing non-aromatic heterocyclic group is preferably a substituted or unsubstituted 1,4-piperidinediyl group or a substituted or unsubstituted 1,4-piperazinediyl group.

[0031] In the above formula (1), R 3 and R 4 is a hydrogen atom, a fluorine atom, or a methyl group, or R 3 and R 4 and are combined together, R 3 The carbon to which R is bonded 4 It is preferable that R forms a ring structure together with the carbon to which it is attached. 3 and R 4 Examples of the ring structure formed by combining R and R together include a cycloolefin ring having 5 to 10 ring members. Of these, a cycloolefin ring having 5 to 8 ring members is preferred. 3 and R 4 Among these, a hydrogen atom, a fluorine atom or a methyl group is preferred, and a hydrogen atom is particularly preferred, in that it can further enhance the effect of improving the film strength.

[0032] -R in the above formula (1) 4 C=CR 3 The group represented by - may be either a cis-type or a trans-type. In terms of enhancing the effect of improving the film strength, -R 4 C=CR 3 The group represented by - is preferably a cis form.

[0033] Partial structure (a) is preferably a structure represented by the following formula (1-1) or (1-2). [ka] (In formula (1-1), R 11 and R 13 is R 11 is a hydrogen atom or a monovalent organic group, and R 13 is a single bond or an alkanediyl group, or R 11 and R 13 are combined together to form R 11 represents a nitrogen-containing non-aromatic heterocyclic structure formed together with the nitrogen atom to which R is attached. 12 and R 14 is R 12 is a hydrogen atom or a monovalent organic group, and R 14 is a single bond or an alkanediyl group, or R 12 and R 14 are combined together to form R 12 represents a nitrogen-containing non-aromatic heterocyclic structure formed together with the nitrogen atom to which R is attached. 3 and R 4 are each independently a hydrogen atom, a halogen atom, or an alkyl group having 1 to 3 carbon atoms. "*" represents a bond. In formula (1-2), R 15 and R 16 R is each independently a single bond or an alkanediyl group. 3 and R 4 are each independently a hydrogen atom, a halogen atom, or an alkyl group having 1 to 3 carbon atoms. "*" represents a bond.

[0034] In the above formula (1-1) and formula (1-2), R 11 , R 12 For the monovalent organic group represented by R in the above formula (1), 7 and R 8 Examples of the groups include the same groups as those exemplified in the description of R 3 and R 4 Regarding R in the above formula (1), 3 and R 4 The same groups as those exemplified in the description of the above may be mentioned.

[0035] R 13 , R 14 When R is an alkanediyl group, it is preferably a linear alkanediyl group, and more preferably a linear alkanediyl group having 1 to 5 carbon atoms. 11 and R 13 a ring structure formed by combining R 12 and R 14 The ring structure formed by combining these is preferably a substituted or unsubstituted 1,4-piperidinediyl group or a substituted or unsubstituted 1,4-piperazinediyl group.

[0036] In order to obtain a liquid crystal device that exhibits good liquid crystal alignment properties and exhibits high VHR and high reliability, the content of structural units derived from monomers having partial structure (a) in polymer [A] is preferably 2 mol% or more relative to the total amount of monomer units contained in polymer [A]. From the above viewpoints, the content of structural units derived from monomers having partial structure (a) is more preferably 5 mol% or more, and even more preferably 7 mol% or more, relative to the total amount of monomer units contained in polymer [A]. Furthermore, the content of structural units derived from monomers having partial structure (a) can be appropriately set depending on the main chain of polymer [A], but is, for example, 60 mol% or less, preferably 50 mol% or less, relative to the total amount of monomer units contained in polymer [A]. Note that polymer [A] may contain only one type of structural unit derived from a monomer having partial structure (a), or two or more types of structural units.

[0037] The main skeleton of the polymer [A] is not particularly limited. In terms of being able to form a highly reliable liquid crystal alignment film having high affinity with liquid crystals and mechanical strength, the polymer [A] is preferably at least one selected from the group consisting of polyamic acid, polyamic acid ester, and polyimide.

[0038] The method for producing polymer [A] is not particularly limited as long as it allows partial structure (a) to be introduced into the main chain of the polymer. In terms of ease of introducing partial structure (a) into the main chain of the polymer, polymer [A] is preferably produced by a polymerization method using a monomer having partial structure (a) in the main chain. In terms of the ability to form a liquid crystal alignment film having high affinity with liquid crystals and mechanical strength, the monomer having partial structure (a) is preferably at least one selected from the group consisting of a diamine compound having partial structure (a) (hereinafter also referred to as a "specific diamine") and a tetracarboxylic dianhydride having partial structure (a) (hereinafter also referred to as a "specific acid anhydride").

[0039] (specific diamine) The specific diamine may be a monomer having the partial structure (a) and two primary amino groups, and the structure of the other parts is not particularly limited. Specifically, the specific diamine is preferably a compound represented by the following formula (2): [ka] (In formula (2), A 1 and A 2 are each independently a single bond, a divalent alicyclic group, or a divalent aromatic ring group. m1 is an integer of 1 to 3. R 1 , R 2 , R 3 and R 4 has the same meaning as in formula (1). When m1 is 2 or 3, a plurality of R 1 ~R 4 are the same or different from each other.)

[0040] In the above formula (2), A 1 and A 2 The divalent alicyclic group represented by the formula (I) is preferably a group obtained by removing two hydrogen atoms from the ring portion of a substituted or unsubstituted alicyclic hydrocarbon ring. Examples of the alicyclic hydrocarbon ring include a cyclobutane ring, a cyclopentane ring, a cyclohexane ring, and a cycloheptane ring. Examples of the substituent introduced into the ring portion of the alicyclic hydrocarbon ring include an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, and a halogen atom.

[0041] A 1 and A 2 The divalent aromatic ring group represented by the formula (I) is a group obtained by removing two hydrogen atoms from the ring portion of a substituted or unsubstituted aromatic ring. The aromatic ring is an aromatic hydrocarbon ring or an aromatic heterocycle, and is preferably an aromatic hydrocarbon ring or a nitrogen-containing aromatic heterocycle. Examples of the substituent introduced into the ring portion of the aromatic ring include an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, and a halogen atom.

[0042] A 1 and A 2 Specific examples of when A is a divalent aromatic ring group include, as the divalent aromatic hydrocarbon ring group, a group obtained by removing any hydrogen atom from the ring moiety of a benzene ring, a biphenyl ring, a naphthalene ring, or an anthracene ring; and as the divalent nitrogen-containing aromatic heterocyclic group, a group obtained by removing any two hydrogen atoms from the ring moiety of a pyridine ring, a pyrimidine ring, a pyridazine ring, or a pyrazine ring. 1 , A 2 The divalent aromatic ring group represented by the following formula (I) is preferably a substituted or unsubstituted phenylene group, biphenylene group or pyridinediyl group, and more preferably a substituted or unsubstituted phenylene group.

[0043] From the viewpoint of obtaining a highly reliable liquid crystal element with little decrease in voltage holding ratio (VHR) even when driven for a long period of time, and from the viewpoint of obtaining a liquid crystal element with good liquid crystal alignment, A 1 and A 2 Among these, is preferably a divalent alicyclic group or a divalent aromatic ring group, and more preferably a divalent aromatic ring group. From the viewpoints of liquid crystal alignment and ease of synthesis, m1 is preferably 1 or 2. Furthermore, from the viewpoint of enhancing the improving effect of the introduction of the partial structure (a), m1 is preferably 2 or more. From the viewpoints of enhancing the liquid crystal alignment and ease of synthesis, and enhancing the improving effect of the voltage holding ratio by the introduction of the partial structure (a), m is particularly preferably 2.

[0044] Preferable specific examples of the specific diamine include a compound represented by the following formula (2-1) and a compound represented by the following formula (2-2). [ka] (In formula (2-1) and formula (2-2), Ar 1 and Ar 2 are each independently a divalent aromatic ring group. m1 is an integer of 1 to 3. R 3 , R 4 , R 11 , R 12 , R 13 , R 14 , R 15 and R 16 has the same meaning as the above formula (1-1) and formula (1-2).

[0045] Specific examples of the specific diamine include compounds represented by the following formulas (3-1) to (3-30): In the compounds represented by the following formulas (3-1) to (3-30), the carbon-carbon unsaturated bond between the two carbonyl groups does not specify structural isomerism, and the compounds may be either cis or trans. [ka] [ka] [ka] [ka] [ka] [ka]

[0046] (Synthesis of specific diamines) The method for synthesizing the specific diamine is not particularly limited. The specific diamine can be synthesized, for example, by synthesizing a diamine containing maleic anhydride and a diamine represented by the formula (2) above.1 -A 1 a method of reacting fumaryl chloride with an amine compound having a partial structure corresponding to "-R" in the above formula (2) (Method 1A); 1 -A 1 The specific diamine can be produced by a method (Method 2A) in which the specific diamine is reacted with an amine compound having a partial structure corresponding to -NH2. The specific diamine can also be produced using a compound represented by the following formula (5) as a raw material (Method 3A). From an industrial viewpoint, it is desirable to obtain a useful diamine with a small number of steps. In this regard, Method 3A is advantageous in that two or more partial structures (a) can be introduced into the specific diamine with a small number of steps. [ka] (In formula (5), R 9 is a single bond or a divalent organic group.

[0047] In Method 3A, a compound represented by the above formula (5) and "-R" in the above formula (2) are 1 -A 1 The reaction is carried out in a solvent as needed, with an amine compound having a partial structure corresponding to -NH2. The solvent is preferably an organic solvent capable of dissolving the raw materials. In Method 3A, the reaction temperature is, for example, 0 to 80°C, and the reaction time is, for example, 30 minutes to 12 hours.

[0048] In the above formula (5), R 9 Examples of the divalent organic group represented by the formula (1) include a divalent hydrocarbon group having 1 to 20 carbon atoms and a divalent group containing -O-, -S-, etc. between the carbon-carbon bond of the hydrocarbon group. For example, by reacting a compound represented by the formula (5) above with a compound represented by the formula (7) below, a compound represented by the formula (8) below can be obtained as the specific diamine. [ka] (In the scheme, R 9 A is a single bond or a divalent organic group. 1 is the same as the above formula (2), and R1 is the same as the above formula (1).

[0049] (Specified acid anhydride) The specific acid anhydride may be a monomer having the partial structure (a) and two acid anhydride groups, and the structure of the other parts is not particularly limited. Specifically, the specific acid anhydride is preferably at least one selected from the group consisting of compounds represented by the following formula (3) and compounds represented by the following formula (4). [ka] (In formula (3) and formula (4), A 3 and A 4 are each independently a trivalent aromatic ring group or an aliphatic ring group. m2 is an integer of 1 to 3. n1 and n2 are each independently an integer of 1 to 3. R 1 , R 2 , R 3 and R 4 has the same meaning as in formula (1). When m2 is 2 or 3, a plurality of R 1 ~R 4 are the same or different from each other.)

[0050] In the above formulas (3) and (4), A 3 and A 4 Examples of the trivalent aliphatic ring group represented by the formula (I) include groups formed by removing three hydrogen atoms from the ring portion of an alicyclic hydrocarbon ring such as a cyclobutane ring, a cyclopentane ring, a cyclohexane ring, or a cycloheptane ring. The alicyclic hydrocarbon ring may have a substituent. Examples of the substituent include an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, and a halogen atom.

[0051] A 3 and A 4The trivalent aromatic ring group represented by the formula (I) is a group obtained by removing three hydrogen atoms from the ring portion of a substituted or unsubstituted aromatic ring. The aromatic ring is an aromatic hydrocarbon ring or an aromatic heterocycle, and is preferably an aromatic hydrocarbon ring or a nitrogen-containing aromatic heterocycle. Examples of the substituent introduced into the ring portion of the aromatic ring include an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, and a halogen atom. From the viewpoint of increasing the density of the liquid crystal alignment film, A 3 , A 4 The trivalent aromatic ring group represented by the following formula (I) is preferably a group having a benzene ring, a biphenyl ring or a pyridine ring, and more preferably a group having a benzene ring.

[0052] From the viewpoint of obtaining a highly reliable liquid crystal element with little decrease in voltage holding ratio (VHR) even when driven for a long period of time, and from the viewpoint of obtaining a liquid crystal element with good liquid crystal alignment, A 3 and A 4 Among these, is preferably a trivalent aromatic ring group, and more preferably a trivalent group having a benzene ring. From the viewpoints of liquid crystal alignment properties and ease of synthesis, m2 is preferably 1 or 2. Furthermore, from the viewpoint of enhancing the improving effect by introducing the partial structure (a), m2 is preferably 2 or more.

[0053] Preferred specific examples of the specific acid anhydride include a compound represented by the following formula (3-1), a compound represented by the following formula (3-2), a compound represented by the following formula (4-1), and a compound represented by the following formula (4-2). [ka] (In formula (3-1) and formula (3-2), Ar 3 and Ar 4 are each independently a trivalent aromatic ring group. m2 is an integer of 1 to 3. R 3 , R 4 , R 11 , R 12 , R 13 , R 14 , R 15 and R 16 has the same meaning as the above formula (1-1) and formula (1-2). [ka] (In formula (4-1) and formula (4-2), m2 is an integer of 1 to 3. n1 and n2 are each independently an integer of 1 to 3. R 3 , R 4 , R 11 , R 12 , R 13 , R 14 , R 15 and R 16 has the same meaning as the above formula (1-1) and formula (1-2).

[0054] In the above formulas (3-1), (3-2), (4-1) and (4-2), R 13 , R 14 , R 15 and R 16 is preferably a single bond from the viewpoint of ease of compound synthesis.

[0055] Specific examples of the specific acid anhydride include compounds represented by the following formulas (4-1) to (4-3): In the compounds represented by the following formulas (4-1) to (4-3), the carbon-carbon unsaturated bond between the two carbonyl groups does not specify structural isomerism, and the compounds may be either cis or trans. [ka]

[0056] (Synthesis of specific acid anhydrides) The method for synthesizing the specific acid anhydride is not particularly limited. The specific acid anhydride can be synthesized, for example, by a method comprising synthesizing fumaryl chloride and a compound represented by the formula (3) or (4) above at "-R 1The specific acid anhydride can be produced by a method (Method 1B) in which the specific acid anhydride is reacted with an amine compound having a partial structure corresponding to the "-acid anhydride group." The specific acid anhydride can also be produced using a compound represented by the following formula (5) as a raw material (Method 2B). From an industrial viewpoint, it is desirable to obtain a useful tetracarboxylic acid dianhydride with a small number of steps. In this regard, Method 2B is advantageous in that two or more partial structures (a) can be introduced into the specific acid anhydride with a small number of steps. [ka] (In formula (5), R 9 is a single bond or a divalent organic group.

[0057] In method 2B, a compound represented by the above formula (5) and "-R" in the above formula (3) or (4) are mixed. 1 -an amine compound having a partial structure corresponding to the "acid anhydride group" is reacted in a solvent as needed. The solvent is preferably an organic solvent capable of dissolving the raw materials. In Method 2B, the reaction temperature is, for example, 0 to 80°C, and the reaction time is, for example, 30 minutes to 12 hours.

[0058] In the above formula (5), R 9 Examples of the divalent organic group represented by the formula (1) include a divalent hydrocarbon group having 1 to 20 carbon atoms and a divalent group containing -O-, -S-, etc. between the carbon-carbon bond of the hydrocarbon group. For example, by reacting a compound represented by the formula (5) above with a compound represented by the formula (9) below, a compound represented by the formula (10) below can be obtained as a specific acid anhydride. [ka] (In the scheme, R 9 A is a single bond or a divalent organic group. 5 is a single bond or an alkanediyl group. 1 has the same meaning as in formula (1) above. n1 is an integer of 1 to 3.

[0059] <Polyamic acid> When the polymer [A] is a polyamic acid, the polyamic acid (hereinafter also referred to as "polyamic acid [A]") can be prepared by, for example, [1] a method of reacting a tetracarboxylic dianhydride containing a specific acid dihydrate with a diamine compound; [2] a method of reacting a tetracarboxylic dianhydride with a diamine compound containing a specific diamine, etc. Methods [1] and [2] may also be combined.

[0060] (Tetracarboxylic acid dianhydride) In synthesizing the polyamic acid [A], one tetracarboxylic dianhydride may be used alone, or two or more tetracarboxylic dianhydrides may be used in combination. The tetracarboxylic dianhydride used in synthesizing the polyamic acid [A] may be only the specific acid anhydride, or may contain a tetracarboxylic dianhydride not having the partial structure (a) (hereinafter also referred to as "other acid dianhydrides"). Examples of other acid dianhydrides include linear aliphatic tetracarboxylic dianhydrides, alicyclic tetracarboxylic dianhydrides, and aromatic tetracarboxylic dianhydrides.

[0061] Specific examples of other acid dianhydrides include, as chain aliphatic tetracarboxylic dianhydrides, 1,2,3,4-butanetetracarboxylic dianhydride, ethylenediaminetetraacetic dianhydride, etc.; as alicyclic tetracarboxylic dianhydrides, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentylacetic dianhydride, 5-(2,5-dioxotetrahydrofuran-3-yl)-3a,4,5,9b-tetrahydronaphtho[1,2-c]furan-1,3-dione, 5-(2,5-dioxotetrahydrofuran-3-yl)-8-methyl-3a,4,5,9b-tetrahydronaphtho[1,2-c]furan-1,3-dione, 2,4,6,8-tetracarboxylic dianhydride, Examples of aromatic tetracarboxylic dianhydrides include pyromellitic dianhydride, 4,4'-(hexafluoroisopropylidene)diphthalic anhydride, ethylene glycol bisanhydrotrimate, 4,4'-(hexafluoroisopropylidene)diphthalic anhydride, 4,4'-carbonyldiphthalic anhydride, and 3,3',4,4'-biphenyltetracarboxylic dianhydride. In addition, the tetracarboxylic dianhydrides described in JP-A-2010-97188 can be used.

[0062] The other acid dianhydrides used in the synthesis of the polyamic acid [A] preferably include at least one selected from the group consisting of linear aliphatic tetracarboxylic acid dianhydrides and alicyclic tetracarboxylic acid dianhydrides, and more preferably alicyclic tetracarboxylic acid dianhydrides, in that they are highly soluble and can produce a liquid crystal alignment film that exhibits good liquid crystal alignment properties and electrical characteristics. The proportion of the alicyclic tetracarboxylic acid dianhydride used is preferably 20 mol % or more, more preferably 40 mol % or more, and even more preferably 50 mol % or more, based on the total amount of tetracarboxylic acid dianhydrides used in the synthesis of the polyamic acid [A].

[0063] When the polyamic acid [A] is produced by the method [1] above, the proportion of the specific acid dianhydride used is preferably 20 mol % or more, more preferably 30 mol % or more, and even more preferably 40 mol % or more, based on the total amount of the tetracarboxylic acid dianhydride used in the synthesis of the polyamic acid [A].

[0064] (diamine compounds) When synthesizing the polyamic acid [A], one diamine compound may be used alone, or two or more diamine compounds may be used in combination. The diamine compound used in synthesizing the polyamic acid [A] may consist solely of the specific diamine, or may contain a diamine compound not having the partial structure (a) (hereinafter also referred to as "other diamines"). Examples of other diamines include linear aliphatic diamines, alicyclic diamines, aromatic diamines, and diaminoorganosiloxanes.

[0065] Specific examples of other diamines include: chain aliphatic diamines such as metaxylylenediamine and hexamethylenediamine; alicyclic diamines such as 1,4-diaminocyclohexane and 4,4'-methylenebis(cyclohexylamine); aromatic diamines such as p-phenylenediamine, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylethane, 4-aminophenyl-4-aminobenzoate, 4,4'-diaminoazobenzene, 3,5-diaminobenzoic acid, 1,5-bis(4-aminophenoxy)pentane, 1,2-bis(4-aminophenoxy)ethane, 1,3-bis(4-aminophenoxy)propane, 1,6-bis(4-aminophenoxy)hexane, 6,6'-(pentamethylenedioxy)bis(3-aminopyridine), N,N'-di(5-amino-2-pyridyl)-N,N'-di( tert-Butoxycarbonyl)ethylenediamine, bis[2-(4-aminophenyl)ethyl]hexanedioic acid, 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylamine, 4,4'-diaminodiphenethyl urea, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 2,2-bis(4-aminophenyl)hexafluoropropane, 1,4-bis(4-aminophenoxy)benzene, 4,4'-bis(4-aminophenoxy)biphenyl, 2,2'-dimethyl-4,4'-diaminobiphenyl, 4,4'-(phenylenediisopropylidene)bisaniline, 2,6-diaminopyridine, 2,4-diaminopyrimidine, 3,6-diaminocarbazole, N-methyl-3,6-diaminocarbazole, 3,6-diaminoacridine, diphenylamine structure-containing monomers, the following formula (F-1): [ka] (In formula (F-1), R 21 and R 22 are each independently an alkanediyl group. 23 is a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or a protecting group. r1 is an integer of 1 to 3. When r1 is 2 or 3, multiple R 22 are the same or different, and multiple R 23 are the same or different.) Main chain diamines such as compounds represented by the following formula: Hexadecanoxy-2,4-diaminobenzene, Octadecanoxy-2,4-diaminobenzene, Octadecanoxy-2,5-diaminobenzene, Cholestanyloxy-3,5-diaminobenzene, Cholesteryloxy-3,5-diaminobenzene, Cholestanyloxy-2,4-diaminobenzene, Cholesteryloxy-2,4-diaminobenzene, Cholestanyloxy-3,5-diaminobenzoate, Cholesteryl 3,5-diaminobenzoate , lanostannyl 3,5-diaminobenzoate, 3,6-bis(4-aminobenzoyloxy)cholestane, 3,6-bis(4-aminophenoxy)cholestane, 4-(4'-trifluoromethoxybenzoyloxy)cyclohexyl-3,5-diaminobenzoate, 1,1-bis(4-((aminophenyl)methyl)phenyl)-4-butylcyclohexane, 3,5-diaminobenzoic acid = 5ξ-cholestan-3-yl, the following formula (E-1): [ka] (In formula (E-1), X I and X II are each independently a single bond, -O-, *-COO-, or *-OCO- (where * indicates the bond to the diaminophenyl group). I is an alkanediyl group having 1 to 3 carbon atoms. II R is a single bond or an alkanediyl group having 1 to 3 carbon atoms. III is an alkyl group, alkoxy group, fluoroalkyl group, or fluoroalkoxy group having 1 to 20 carbon atoms. a is 0 or 1. b is an integer of 0 to 3. c is an integer of 0 to 2. d is 0 or 1, provided that 1≦a+b+c≦3. A side chain type diamine or the like, such as a compound represented by Examples of diaminoorganosiloxanes include 1,3-bis(3-aminopropyl)-tetramethyldisiloxane.

[0066] Examples of the compound represented by the formula (F-1) include compounds represented by the following formulas (F-1-1) to (F-1-3). Examples of the compound represented by the formula (E-1) include compounds represented by the following formulas (E-1-1) to (E-1-4). As the other diamines, one type can be used alone, or two or more types can be used in combination. In the formulas, "Boc" represents a tert-butoxycarbonyl group (the same applies hereinafter). [ka]

[0067] When the polyamic acid [A] is produced by the method [2] above, the proportion of the specific diamine used is preferably 20 mol % or more, more preferably 30 mol % or more, and even more preferably 40 mol % or more, based on the total amount of the diamine compounds used in the synthesis of the polyamic acid [A].

[0068] (Synthesis of polyamic acid) The polyamic acid [A] can be obtained by reacting a tetracarboxylic dianhydride with a diamine compound, optionally together with a molecular weight modifier. One preferred embodiment of the method for producing the polyamic acid [A] includes reacting a tetracarboxylic dianhydride with a diamine compound using a monomer containing at least one selected from the group consisting of the specific diamine obtained by the above method 3A and the specific acid dianhydride obtained by the above method 2B.

[0069] In the synthesis reaction of the polyamic acid [A], the ratio of the tetracarboxylic dianhydride to the diamine compound is preferably such that 0.2 to 2 equivalents of the acid anhydride group of the tetracarboxylic dianhydride are used per equivalent of the amino group of the diamine compound. Examples of molecular weight modifiers include acid monoanhydrides such as maleic anhydride, phthalic anhydride, and itaconic anhydride; monoamine compounds such as aniline, cyclohexylamine, and n-butylamine; and monoisocyanate compounds such as phenyl isocyanate and naphthyl isocyanate. The ratio of the molecular weight modifier used is preferably 20 parts by mass or less per 100 parts by mass of the total of the tetracarboxylic dianhydride and diamine compound used.

[0070] The synthesis reaction of the polyamic acid [A] is preferably carried out in an organic solvent. The reaction temperature is preferably −20° C. to 150° C., and the reaction time is preferably 0.1 to 24 hours. Examples of organic solvents used in the reaction include aprotic polar solvents, phenolic solvents, alcoholic solvents, ketone solvents, ester solvents, ether solvents, halogenated hydrocarbons, and hydrocarbons. Among these, it is preferable to use one or more solvents selected from the group consisting of N-methyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide, dimethyl sulfoxide, γ-butyrolactone, tetramethylurea, hexamethylphosphortriamide, m-cresol, xylenol, and halogenated phenols as the reaction solvent, or to use a mixture of one or more of these solvents with other organic solvents (e.g., butyl cellosolve, diethylene glycol diethyl ether, etc.). The amount of organic solvent used is preferably such that the total amount of the tetracarboxylic dianhydride and the diamine compound is 0.1 to 50% by mass based on the total amount of the reaction solution.

[0071] In this manner, a polymer solution containing the polyamic acid [A] dissolved therein is obtained. This polymer solution may be used as is for preparing a liquid crystal aligning agent, or the polyamic acid [A] contained in the polymer solution may be isolated and then used for preparing a liquid crystal aligning agent.

[0072] Polyamic acid ester When the polymer [A] is a polyamic acid ester, the polyamic acid ester (hereinafter also referred to as "polyamic acid ester [A]") can be obtained, for example, by a method such as [I] reacting a polyamic acid [A] with an esterifying agent, [II] reacting a tetracarboxylic acid diester with a diamine compound containing a specific diamine, or [III] reacting a tetracarboxylic acid diester dihalide with a diamine compound containing a specific diamine. The polyamic acid ester [A] may have only an amic acid ester structure, or may be a partially esterified product in which an amic acid structure and an amic acid ester structure coexist. The reaction solution in which the polyamic acid ester [A] is dissolved may be used directly for preparing a liquid crystal aligning agent, or the polyamic acid ester [A] contained in the reaction solution may be isolated and then used for preparing a liquid crystal aligning agent.

[0073] Polyimide When the polymer [A] is a polyimide, the polyimide (hereinafter also referred to as "polyimide [A]") can be obtained, for example, by imidizing the polyamic acid [A] synthesized as described above through dehydration and cyclization. The polyimide [A] may be a fully imidized product in which all of the amic acid structures contained in its precursor polyamic acid [A] have been dehydrated and cyclized, or a partially imidized product in which only a portion of the amic acid structures have been dehydrated and cyclized, resulting in both amic acid structures and imide ring structures. The polyimide [A] preferably has an imidization rate of 20 to 99%, more preferably 30 to 90%. The imidization rate is the ratio, expressed as a percentage, of the number of imide ring structures to the total number of amic acid structures and imide ring structures in the polyimide. Here, some of the imide rings may be isoimide rings.

[0074] The dehydration ring closure of the polyamic acid [A] is preferably carried out by dissolving the polyamic acid [A] in an organic solvent, adding a dehydrating agent and a dehydration ring closure catalyst to the solution, and heating as needed. In this method, the dehydrating agent may be, for example, an acid anhydride such as acetic anhydride, propionic anhydride, or trifluoroacetic anhydride. The amount of the dehydrating agent used is preferably 0.01 to 20 moles per mole of the amic acid structure of the polyamic acid [A]. The dehydration ring closure catalyst may be, for example, a tertiary amine such as pyridine, collidine, lutidine, or triethylamine. The amount of the dehydration ring closure catalyst used is preferably 0.01 to 10 moles per mole of the dehydrating agent used. Examples of organic solvents used in the dehydration ring closure reaction include the organic solvents exemplified for use in the synthesis of the polyamic acid [A]. The reaction temperature for the dehydration ring closure reaction is preferably 0 to 180°C. The reaction time is preferably 1.0 to 120 hours. The reaction solution containing the polyimide [A] may be used for preparing a liquid crystal aligning agent as it is, or the polyimide [A] may be isolated and then used for preparing a liquid crystal aligning agent.

[0075] When the polymer [A] is at least one selected from the group consisting of polyamic acid, polyamic acid ester, and polyimide, the solution viscosity of the polymer [A] is preferably 10 to 800 mPa·s, and more preferably 15 to 500 mPa·s, when the polymer is prepared as a 10% by mass solution. The solution viscosity (mPa·s) is a value measured at 25°C using an E-type rotational viscometer for a 10% by mass polymer solution prepared using a good solvent for the polymer [A] (e.g., γ-butyrolactone, N-methyl-2-pyrrolidone, etc.).

[0076] The weight average molecular weight (Mw) of the polymer [A] measured by gel permeation chromatography (GPC) in terms of polystyrene is preferably 1,000 to 500,000, more preferably 2,000 to 300,000. The molecular weight distribution (Mw / Mn), which is the ratio of Mw to the number average molecular weight (Mn) measured by GPC in terms of polystyrene, is preferably 7 or less, more preferably 5 or less. When preparing the liquid crystal aligning agent, one type of polymer [A] may be used alone, or two or more types may be used in combination.

[0077] <Other ingredients> The liquid crystal aligning agent may contain, in addition to the polymer [A], components different from the polymer [A] (hereinafter also referred to as "other components"), if necessary.

[0078] Polymer [Q] The liquid crystal aligning agent of the present disclosure may further contain, as a polymer component, a polymer not having the partial structure (a) (hereinafter also referred to as "polymer [Q]").

[0079] The main skeleton of the polymer [Q] is not particularly limited. Examples of the polymer [Q] include polyamic acid, polyamic acid ester, polyimide, polyorganosiloxane, polyester, polyenamine, polyurea, polyamide, polyamideimide, polybenzoxazole precursor, polybenzoxazole, cellulose derivative, polyacetal, (meth)acrylic polymer, styrene polymer, maleimide polymer, styrene-maleimide copolymer, etc. From the viewpoint of obtaining a highly reliable liquid crystal device, the polymer [Q] is preferably at least one selected from the group consisting of polyamic acid, polyamic acid ester, polyimide, polyorganosiloxane, and addition polymer. Examples of the addition polymer include (meth)acrylic polymer, styrene polymer, maleimide polymer, styrene-maleimide copolymer, etc.

[0080] When the liquid crystal aligning agent of the present disclosure contains polymer [A] and polymer [Q] together, the content of polymer [Q] is preferably 1% by mass or more, more preferably 2% by mass or more, based on the total amount of polymer [A] and polymer [Q]. The content of polymer [Q] is preferably 95% by mass or less, more preferably 90% by mass or less, based on the total amount of polymer [A] and polymer [Q]. Polymer [Q] may be used singly or in combination of two or more.

[0081] ·solvent The liquid crystal aligning agent of the present disclosure is prepared as a liquid composition in which a polymer component and other components used as needed are dispersed or dissolved preferably in a suitable solvent.

[0082] As the solvent, an organic solvent is preferably used, specific examples of which include N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 1,2-dimethyl-2-imidazolidinone, 1,3-dimethyl-2-imidazolidinone, phenol, γ-butyrolactone, γ-butyrolactam, N,N-dimethylformamide, N,N-dimethylacetamide, 4-hydroxy-4-methyl-2-pentanone, diacetone alcohol, 1-hexanol, 2-hexanol, propane-1,2-diol, 3-methoxy-1-butanol, ethylene glycol monomethyl ether, methyl lactate, ethyl lactate, butyl lactate, methyl acetate, ethyl acetate, butyl acetate, methyl acetoacetate, ethyl acetoacetate, ethyl propionate, methyl methoxypropionate, ethyl ethoxypropionate, ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol-n-propyl ether, and ethylene glycol-i-propyl ether. Examples of suitable solvents include ethylene glycol ether, ethylene glycol-n-butyl ether (butyl cellosolve), ethylene glycol dimethyl ether, ethylene glycol ethyl ether acetate, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diisobutyl ketone, isoamyl propionate, isoamyl isobutyrate, diisopentyl ether, ethylene carbonate, propylene carbonate, propylene glycol monomethyl ether (PGME), diethylene glycol diethyl ether acetate, propylene glycol monomethyl ether acetate (PGMEA), propylene glycol diacetate, cyclopentanone, cyclohexanone, etc. The solvent may be used alone or in combination of two or more.

[0083] In addition to the above, other components contained in the liquid crystal aligning agent include, for example, a crosslinking agent, an antioxidant, a metal chelate compound, a curing accelerator, a surfactant, a filler, a dispersant, a photosensitizer, etc. The blending ratio of the other components can be appropriately selected depending on each compound within a range that does not impair the effects of the present disclosure.

[0084] The solid content concentration in the liquid crystal aligning agent (the proportion of the total mass of the components other than the solvent in the liquid crystal aligning agent to the total mass of the liquid crystal aligning agent) is appropriately selected taking into consideration viscosity, volatility, etc., but is preferably in the range of 1 to 10 mass %. A solid content concentration of 1 mass % or more is preferable in that it ensures a sufficient coating film thickness and makes it possible to obtain a liquid crystal alignment film that exhibits better liquid crystal alignment properties. On the other hand, a solid content concentration of 10 mass % or less makes it possible to make the coating film have an appropriate thickness, making it easier to obtain a liquid crystal alignment film that exhibits good liquid crystal alignment properties, and also tends to make the viscosity of the liquid crystal aligning agent appropriate, resulting in good coatability.

[0085] According to the present disclosure described above, the following liquid crystal aligning agent is provided. <1> A liquid crystal aligning agent comprising a polymer [A] having a partial structure (a) represented by the above formula (1) in its main chain. <2> The polymer [A] contains a structural unit derived from a diamine having the partial structure (a). <1> The liquid crystal aligning agent according to claim 1. <3> The diamine is a compound represented by the formula (2). <2> The liquid crystal aligning agent according to claim 1. <4> The polymer [A] contains a structural unit derived from a tetracarboxylic acid derivative having the partial structure (a). <1> ~ <3> 10. The liquid crystal aligning agent according to any one of the preceding items. <5> The tetracarboxylic acid derivative is at least one selected from the group consisting of a compound represented by the formula (3) and a compound represented by the formula (4). <4> The liquid crystal aligning agent according to claim 1. <6> The polymer [A] is at least one selected from the group consisting of polyamic acid, polyamic acid ester, and polyimide. <1> ~ <5> 10. The liquid crystal aligning agent according to any one of the preceding items. <7> The polymer [A] contains a structural unit derived from an alicyclic tetracarboxylic dianhydride. <1> ~ <6> 10. The liquid crystal aligning agent according to any one of the preceding items. <8> The above-mentioned polymer [Q] further contains no partial structure (a). <1> ~ <7> 10. The liquid crystal aligning agent according to any one of the preceding items.

[0086] <Liquid crystal alignment film and liquid crystal element> The liquid crystal alignment film of the present disclosure is manufactured using the liquid crystal alignment agent prepared as described above. Furthermore, the liquid crystal element of the present disclosure includes a liquid crystal alignment film formed using the liquid crystal alignment agent described above. The liquid crystal driving method in the liquid crystal element is not particularly limited, and can be applied to various modes, such as TN type, STN type, VA type (including VA-MVA type, VA-PVA type, etc.), IPS type, FFS type, OCB (Optically Compensated Bend) type, and PSA (Polymer Sustained Alignment) type. The liquid crystal element can be manufactured, for example, by a method including the following steps 1 to 3. In step 1, different substrates are used depending on the desired operation mode. Steps 2 and 3 are common to all operation modes.

[0087] <Step 1: Formation of coating film> First, a liquid crystal alignment agent is applied to a substrate, and the coated surface is preferably heated to form a coating film on the substrate. Examples of substrates that can be used include transparent substrates made of glass, such as float glass or soda glass; or plastics, such as polyethylene terephthalate, polybutylene terephthalate, polyethersulfone, polycarbonate, and poly(alicyclic olefin). Examples of transparent conductive films that can be provided on one side of the substrate include NESA films (registered trademarks of PPG, Inc., USA) made of tin oxide (SnO2) and ITO films made of indium oxide-tin oxide (In2O3-SnO2). When manufacturing TN, STN, or VA liquid crystal devices, two substrates with patterned transparent conductive films are used. On the other hand, when manufacturing IPS or FFS liquid crystal devices, a substrate with comb-patterned electrodes and an opposing substrate without electrodes are used.

[0088] The method for applying the liquid crystal aligning agent to the substrate is not particularly limited. The liquid crystal aligning agent can be applied to the substrate by, for example, a spin coating method, a printing method (for example, an offset printing method, a flexographic printing method, etc.), an inkjet method, a slit coating method, a bar coater method, an extrusion die method, a direct gravure coater method, a chamber doctor coater method, an offset gravure coater method, an impregnation coater method, an MB coater method, etc.

[0089] After the liquid crystal aligning agent is applied, preliminary heating (pre-baking) is preferably carried out for the purpose of preventing dripping of the applied liquid crystal aligning agent. The pre-baking temperature is preferably 30 to 200°C, and the pre-baking time is preferably 0.25 to 10 minutes. Thereafter, the solvent is completely removed, and if necessary, a baking (post-baking) step is carried out for the purpose of thermally imidizing the amic acid structure present in the polymer. The baking temperature (post-baking temperature) at this time is preferably 80 to 280°C, more preferably 80 to 250°C. The post-baking time is preferably 5 to 200 minutes. The thickness of the film formed is preferably 0.001 to 1 μm.

[0090] <Step 2: Alignment Treatment> When producing a TN-type, STN-type, IPS-type, or FFS-type liquid crystal device, the coating film formed in step 1 above is subjected to a treatment (alignment treatment) to impart liquid crystal alignment ability. This imparts the ability to align liquid crystal molecules to the coating film, turning it into a liquid crystal alignment film. As the alignment treatment, a rubbing treatment in which the surface of the coating film formed on the substrate is rubbed with cotton, nylon, or the like, or a photo-alignment treatment in which the coating film is irradiated with light to impart liquid crystal alignment ability is preferably used. When producing a vertical alignment type liquid crystal device, the coating film formed in step 1 above may be used as a liquid crystal alignment film as is, or the coating film may be subjected to an alignment treatment to further enhance the liquid crystal alignment ability.

[0091] Light irradiation for photoalignment can be performed by irradiating the coating film after the post-bake step, irradiating the coating film after the pre-bake step but before the post-bake step, or irradiating the coating film while it is being heated in at least one of the pre-bake step and the post-bake step. The radiation to be irradiated to the coating film can be, for example, ultraviolet light and visible light containing light with a wavelength of 150 to 800 nm. Preferably, ultraviolet light containing light with a wavelength of 200 to 400 nm is used. When the radiation is polarized, it may be linearly polarized or partially polarized. When the radiation used is linearly polarized or partially polarized, irradiation may be performed from a direction perpendicular to the substrate surface, from an oblique direction, or a combination of these. When non-polarized radiation is used, the irradiation direction is an oblique direction.

[0092] Examples of light sources that can be used include low-pressure mercury lamps, high-pressure mercury lamps, deuterium lamps, metal halide lamps, argon resonance lamps, xenon lamps, excimer lasers, etc. The radiation dose is preferably 200 to 30,000 J / m 2 and more preferably 500 to 10,000 J / m 2 After the light irradiation for imparting alignment ability, the substrate surface may be washed with, for example, water, an organic solvent (e.g., methanol, isopropyl alcohol, 1-methoxy-2-propanol acetate, butyl cellosolve, ethyl lactate, etc.) or a mixture thereof, or the substrate may be heated.

[0093] <Step 3: Construction of liquid crystal cell> Two substrates with liquid crystal alignment films formed thereon are prepared as described above, and a liquid crystal cell is produced by disposing a liquid crystal between the two substrates arranged opposite each other. Examples of methods for producing a liquid crystal cell include disposing two substrates with a gap between them so that the liquid crystal alignment films face each other, bonding the peripheries of the two substrates together with a sealant, injecting liquid crystal into the cell gap surrounded by the substrate surfaces and the sealant, and sealing the injection hole, and using the ODF method. Examples of sealants that can be used include epoxy resins containing a curing agent and aluminum oxide spheres as spacers. Examples of liquid crystals include nematic liquid crystals and smectic liquid crystals, with nematic liquid crystals being preferred.

[0094] In the PSA mode, a polymerizable compound (e.g., a polyfunctional (meth)acrylate compound) is filled into the cell gap together with the liquid crystal, and after the liquid crystal cell is constructed, the liquid crystal cell is irradiated with light while a voltage is applied between the conductive films of the pair of substrates. In producing a PSA mode liquid crystal element, the proportion of the polymerizable compound used is 0.01 to 3 parts by mass, preferably 0.1 to 1 part by mass, per 100 parts by mass of the total liquid crystal.

[0095] When manufacturing a liquid crystal display device, a polarizing plate is subsequently attached to the outer surface of the liquid crystal cell. Examples of polarizing plates include a polarizing film called an "H film" made by stretching and aligning polyvinyl alcohol and absorbing iodine, sandwiched between cellulose acetate protective films, and a polarizing plate made of the H film itself.

[0096] The liquid crystal element of the present disclosure can be effectively applied to various applications, specifically, for example, various display devices such as clocks, portable game machines, word processors, notebook computers, car navigation systems, camcorders, PDAs, digital cameras, mobile phones, smartphones, various monitors, liquid crystal televisions, and information displays, as well as light control devices, retardation films, and the like. [Example]

[0097] Hereinafter, the present invention will be described in more detail based on examples, but the present invention should not be construed as being limited by the following examples.

[0098] In the following examples, the imidization rate of polyimide in a polymer solution was measured by the following method. The required amounts of raw material compounds and polymers used in the following examples were secured by repeating synthesis on a synthesis scale shown in the following synthesis examples as necessary.

[0099] [Imidization rate of polyimide] The polyimide solution was poured into pure water, and the resulting precipitate was thoroughly dried under reduced pressure at room temperature. After that, it was dissolved in deuterated dimethyl sulfoxide and measured at room temperature using tetramethylsilane as a standard substance. 1 H-NMR measurement was carried out. 1 The imidization rate [%] was calculated from the H-NMR spectrum using the following formula (1). Imidization rate [%] = (1 - (A 1 / (A 2 ×α)))×100 …(1) (In formula (1), A 1 is the peak area due to the proton of the NH group that appears at a chemical shift of around 10 ppm, and A 2 is the peak area due to other protons, and α is the ratio of the number of other protons to one proton of the NH group in the polymer precursor (polyamic acid).

[0100] The abbreviations for the compounds are as follows: In the following, the compound represented by formula (X) may be simply referred to as "compound (X)".

[0101] (Tetracarboxylic acid dianhydride) [ka] [ka]

[0102] (diamine compounds) [ka] [ka] [ka]

[0103] [ka] [ka]

[0104] (Other compounds) [ka] [ka]

[0105] <Monomer synthesis> 1. Synthesis of Compounds (DA-1), (DA-8) and (DA-9) Compounds (DA-1), (DA-8), and (DA-9) were synthesized by a method similar to that described in Japanese Patent No. 6013823. The manufacturing method of compound (DA-1) is shown below.

[0106] Synthesis of compound (DA-1) A reaction vessel was charged with 30 g (0.2 mol) of 4-(2-methylamino-ethyl)-phenylamine and 200 ml of tetrahydrofuran. A solution of 20 g (0.2 mol) of maleic anhydride in 30 ml of tetrahydrofuran was added dropwise to the reaction vessel under ice cooling, and the mixture was stirred overnight at room temperature. After the reaction was complete, the precipitated solid was collected by filtration, washed three times with 20 ml of tetrahydrofuran, and dried at 60 °C for 3 hours to obtain a brown solid. Subsequently, 30 g (0.2 mol) of 4-(2-methylamino-ethyl)-phenylamine, 0.5 g of dimethylaminopyridine, and 100 ml of dimethylformamide were charged to the reaction vessel containing the resulting solid. 38 g (0.2 mol) of 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide hydrochloride was added to the reaction vessel under ice cooling, and the mixture was stirred overnight at room temperature. After the reaction was complete, 300 ml of water was added, and the mixture was extracted three times with 300 ml of ethyl acetate. After drying with sodium sulfate, the solvent was distilled off to obtain 28 g of a brown viscous solid. 80 ml of methanol was added to the obtained solid, and the insoluble solid was filtered off to obtain 20 g of compound (DA-1) as a brown solid. 1 The H-NMR measurement results are as follows: 1 H-NMR (300 MHz, DMSO-d 6 )δppm:7.02(4H,d),6.53(4H,d),6.44(2H,s),3.22-3.57(10H,m),2.62(4H,t).

[0107] 2. Synthesis of Compounds (DA-2) to (DA-7) Compounds (DA-2) to (DA-7) were produced by first preparing compounds (D-1) to (D-4) with reference to the method described in the reference document (Journal of Polymer Science: Polymer Chemistry Edition 1975, Vol. 13, 1691-1698), and then using the resulting compounds (D-1) to (D-4) as intermediates. The production method for compound (DA-2) is shown below. Compounds (DA-2) to (DA-7) are cis-isomers.

[0108] Synthesis of compound (DA-2) A reaction vessel was charged with 19.6 g (0.2 mol) of maleic anhydride and 100 ml of acetic acid. A solution of 5.0 g (0.1 mol) of hydrazine monohydrate dissolved in 25 ml of acetic acid was added dropwise. During the dropwise addition, the reaction temperature was controlled using an ice bath to prevent the reaction solution from exceeding 25°C. After the dropwise addition, the mixture was left to stand for 3 hours, and the precipitate was collected by filtration and washed three times with 30 ml of ethanol. It was then dried at 60°C for 5 hours to obtain 21 g of a pale yellow solid. The obtained solid was transferred to a reaction vessel, and 110 ml of thionyl chloride was added, followed by stirring at 75°C for 6 hours. After the reaction, the mixture was cooled to room temperature, and the precipitate was collected by filtration. The precipitate was washed with hexane and dried at 60°C for 5 hours to obtain 10 g (0.05 mol) of compound (D-1). The obtained compound (D-1) was dissolved in 50 ml of N-methyl-2-pyrrolidone, and 14 g (0.1 mol) of 2-(4-aminophenyl)ethylamine was added dropwise over 30 minutes. After the dropwise addition, the mixture was stirred at room temperature for 1 hour, and the reaction solution was added to 500 ml of water to obtain a precipitate. The obtained precipitate was collected by filtration, washed with water, and then dried at 60°C for 5 hours to obtain 20 g of compound (DA-2). 1 The H-NMR measurement results are as follows: 1 H-NMR (300 MHz, DMSO-d 6 )δppm:8.96(2H,s),6.89(4H,m),6.51(4H,m),6.19-6.31(4H,m),3.29(4H,m),2.60(4H,m).

[0109] 3. Synthesis of Compound (DA-10) A reaction vessel was charged with 13.9 g (0.1 mol) of 2-amino-5-nitropyridine, 7.9 g (0.1 mol) of pyridine, and 50 mL of tetrahydrofuran. A solution of 7.6 g (0.05 mol) of fumaryl chloride dissolved in 25 mL of tetrahydrofuran was added dropwise. After the addition was complete, the mixture was stirred at room temperature for 8 hours. The resulting reaction solution was poured into water, and the precipitate was collected by filtration. The resulting solid was washed with water and ethanol and dried at 60 °C for 5 hours to obtain 14.5 g of the intermediate as a brown solid. The resulting intermediate was transferred to a reaction vessel, and 10 wt% palladium on carbon (2 g) and N,N-dimethylformamide (30 mL) were added. The mixture was heated at 50 °C for 8 hours under a hydrogen atmosphere. The reaction solution was filtered to remove the catalyst, and the filtrate was poured into ice water. The resulting precipitate was collected by filtration. The resulting solid was washed with ethanol and dried at 60 °C for 5 hours to obtain 12.2 g of compound (DA-10). Compound (DA-10) 1 The H-NMR measurement results are as follows: 1 H-NMR (300 MHz, DMSO-d 6 )δppm:11.2(2H,s),7.13-7.44(6H,m),6.18(2H,s).

[0110] 4. Synthesis of Compound (DA-12) Compound (DA-12) was synthesized in the same manner as in the synthesis of compound (DA-10), except that 4-nitroaniline was used instead of 2-amino-5-nitropyridine as the starting material.

[0111] 5. Synthesis of Compound (DA-11) A reaction vessel was charged with 13.9 g (0.1 mol) of 2-amino-5-nitropyridine, 7.9 g (0.1 mol) of pyridine, and 50 ml of tetrahydrofuran. A solution of 7.6 g (0.05 mol) of fumaryl chloride dissolved in 25 ml of tetrahydrofuran was added dropwise. After the addition was complete, the mixture was stirred at room temperature for 8 hours. The resulting reaction solution was poured into water, and the precipitate was collected by filtration. The resulting solid was washed with water and ethanol and dried at 60°C for 5 hours to obtain 14.5 g of the intermediate as a brown solid. The resulting intermediate was transferred to a reaction vessel, and 25 ml of dimethylformamide was added. 18 g (0.08 mol) of di-tert-butyl dicarbonate was added, and the mixture was stirred at room temperature for 16 hours. The reaction solution was added dropwise to water, and the precipitate was collected by filtration, washed with water, and then dried at 60°C for 3 hours to obtain 13.2 g of a light brown solid. The obtained solid was transferred to a reaction vessel, and 10 wt% palladium / carbon (1.8 g) and N,N-dimethylformamide (30 ml) were added, followed by heating at 50°C for 8 hours under a hydrogen atmosphere. The reaction solution was filtered to remove the catalyst, and the filtrate was poured into ice water, and the resulting precipitate was collected by filtration. The obtained solid was washed with ethanol and dried at 60°C for 5 hours to obtain 9.8 g of compound (DA-11). 1 The H-NMR measurement results are as follows: 1 H-NMR (300 MHz, DMSO-d 6 )δppm:8.09(2H,m),7.28-7.44(4H,m),6.93(2H,s),1.39(18H,s).

[0112] 6. Synthesis of Compound (DA-13) Compound (DA-13) was synthesized in the same manner as in the synthesis of (DA-11), except that 4-nitroaniline was used instead of 2-amino-5-nitropyridine as the starting material.

[0113] 7. Synthesis of Compound (TA-1) A reaction vessel was charged with 11.5 g (0.1 mol) of 3-aminodihydrofuran-2,5-dione, 7.9 g (0.1 mol) of pyridine, and 300 ml of tetrahydrofuran. The reaction solution was cooled to 0°C in an ice bath, and a solution of 7.6 g (0.05 mol) of fumaryl chloride in 50 ml of tetrahydrofuran was added dropwise. After the addition was complete, the mixture was stirred at room temperature for 4 hours. After the reaction, the solvent was removed under reduced pressure. Subsequently, 50 g of acetic acid and 50 g of acetic anhydride were added, and the mixture was stirred at 100°C for 3 hours. The resulting precipitate was collected by filtration, washed with acetic acid and normal hexane, and then dried under reduced pressure at 60°C for 5 hours to obtain compound (TA-1).

[0114] 8. Synthesis of Compound (TA-2) Compound (TA-2) was synthesized in the same manner as in the synthesis of compound (TA-1), except that 5-hydroxyisobenzofuran-1,3-dione was used instead of 3-aminodihydrofuran-2,5-dione as the starting material.

[0115] 9. Synthesis of Compound (TA-3) A reaction vessel was charged with 19.6 g (0.2 mol) of maleic anhydride and 100 ml of acetic acid. A solution of 5.0 g (0.1 mol) of hydrazine monohydrate dissolved in 25 ml of acetic acid was added dropwise. During the dropwise addition, the reaction temperature was controlled using an ice bath to prevent the reaction solution from exceeding 25°C. After the dropwise addition, the mixture was left to stand for 3 hours, and the precipitate was collected by filtration and washed three times with 30 ml of ethanol. It was then dried at 60°C for 5 hours to obtain 21 g of a pale yellow solid. The obtained solid was transferred to a reaction vessel, and 110 ml of thionyl chloride was added and stirred at 75°C for 6 hours. After the reaction, the mixture was cooled to room temperature, and the precipitate was collected by filtration. The precipitate was washed with hexane and dried at 60°C for 5 hours to obtain 10 g (0.05 mol) of compound (D-1). The obtained compound (D-1) was dissolved in 50 ml of N-methyl-2-pyrrolidone, and 11.5 g (0.1 mol) of 3-aminodihydrofuran-2,5-dione was added dropwise over 30 minutes. After the addition, the mixture was stirred at room temperature for 4 hours. After the reaction, the solvent was removed under reduced pressure. Subsequently, 50 g of acetic acid and 50 g of acetic anhydride were added, and the mixture was stirred at 100°C for 3 hours. The resulting precipitate was collected by filtration, washed with acetic acid and normal hexane, and then dried under reduced pressure at 60°C for 5 hours to obtain compound (TA-3). Note that compound (TA-3) is a cis-isomer.

[0116] <Polymer synthesis> 1. Synthesis of polyamic acid [Synthesis Example 1] 100 parts by mole of 1,2,3,4-cyclobutanetetracarboxylic dianhydride (compound (TB-1)) as a tetracarboxylic dianhydride and 100 parts by mole of compound (DA-2) as a diamine compound were dissolved in N-methyl-2-pyrrolidone (NMP), and the mixture was allowed to react at room temperature for 6 hours to obtain a solution containing 15% by mass of polyamic acid (referred to as polymer (PAA-1)).

[0117] Polymer (PAA-1) can also be obtained by polymerizing intermediate compound (D-1) without using isolated compound (DA-2). Different synthesis methods for polymer (PAA-1) are shown below. [Alternative synthesis of PAA-1] 100 moles of compound (D-1) was dissolved in N-methyl-2-pyrrolidone, and 200 moles of 2-(4-aminophenyl)ethylamine was added dropwise over 30 minutes. After the dropwise addition, the mixture was stirred at room temperature for 1 hour. 100 moles of 1,2,3,4-cyclobutanetetracarboxylic dianhydride was then added as a tetracarboxylic dianhydride, and the mixture was allowed to react at room temperature for 6 hours to obtain a solution containing 15% by mass of polymer (PAA-1).

[0118] [Synthesis Examples 2 to 24] Polyamic acids (polymers (PAA-2) to (PAA-20) and polymers (paa-1) to (paa-4)) were obtained by the same procedure as in Synthesis Example 1, except that the types and amounts of the tetracarboxylic dianhydrides and diamine compounds used were changed as shown in Table 1. In Table 1, the numerical values ​​for the tetracarboxylic dianhydrides (acid dianhydrides 1 and 2) represent the ratio (molar ratio) of each compound to 100 parts by mole of the total amount of the tetracarboxylic dianhydrides used in the synthesis of the polyamic acid. The numerical values ​​for the diamine compounds (diamines 1 to 3) represent the ratio (molar ratio) of each compound to 100 parts by mole of the total amount of the diamine compounds used in the synthesis of the polyamic acid.

[0119] [Table 1]

[0120] 2. Polyimide Synthesis [Synthesis Example 25] Tetracarboxylic dianhydrides (60 mol parts of compound (TB-1) and 40 mol parts of compound (TB-3)), and diamine compounds (20 mol parts of compound (DA-2), 60 mol parts of compound (DB-2), and 20 mol parts of compound (DB-3)) were dissolved in NMP and reacted at room temperature for 6 hours to obtain a solution containing 15% by weight of polyamic acid. Next, NMP was added to the resulting polyamic acid solution to obtain a solution with a polyamic acid concentration of 10% by weight, and pyridine and acetic anhydride were added to carry out a dehydration ring-closing reaction at 60°C for 4 hours. After the dehydration ring-closing reaction, the solvent in the system was replaced with fresh NMP to obtain a solution containing 15% by weight of polyimide (referred to as polymer (PI-1)) with an imidization rate of approximately 80%.

[0121] [Synthesis Examples 26-30] Polyimides (polymers (PI-2), (PI-3), and (PI-1) to (PI-3)) were obtained by the same procedure as in Synthesis Example 25, except that the types and amounts of the tetracarboxylic dianhydrides and diamine compounds used were changed as shown in Table 2. In Table 2, the values ​​for the tetracarboxylic dianhydrides (acid dianhydrides 1 to 3) represent the ratio (molar ratio) of each compound to 100 parts by mole of the total amount of the tetracarboxylic dianhydrides used in the synthesis of the polyimide. The values ​​for the diamine compounds (diamines 1 to 4) represent the ratio (molar ratio) of each compound to 100 parts by mole of the total amount of the diamine compounds used in the synthesis of the polyimide.

[0122] [Table 2]

[0123] 3. Synthesis of polyorganosiloxane [Synthesis Example 31] A 1000 ml three-neck flask was charged with 100.0 g of 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane (compound (s-1)), 500 g of methyl isobutyl ketone, and 10.0 g of triethylamine, and the mixture was mixed at room temperature. Next, 100 g of deionized water was added dropwise from the dropping funnel over 30 minutes, and the mixture was then refluxed and mixed at 80°C for 6 hours. After the reaction was complete, the organic layer was removed and washed with a 0.2% by weight aqueous solution of ammonium nitrate until the water was neutral, after which the solvent and water were distilled off under reduced pressure. An appropriate amount of methyl isobutyl ketone was added to obtain a 50% by weight solution of polymer (ESSQ-1), a polyorganosiloxane having epoxy groups. In a 500 ml three-neck flask, 3.10 g of compound (c-1) (20 mol% relative to the amount of epoxy groups in the polymer (ESSQ-1)), 3.24 g of compound (c-2) (10 mol% relative to the amount of epoxy groups in the polymer (ESSQ-1)), 1.00 g of tetrabutylammonium bromide, 20.0 g of a solution containing the polymer (ESSQ-1), and 290.0 g of methyl isobutyl ketone were added and stirred at 90 ° C. for 18 hours. After cooling to room temperature, the separation and washing operation with distilled water was repeated 10 times. The organic layer was then recovered, concentrated using a rotary evaporator, and diluted with NMP twice. The solids concentration was then adjusted to 10% by mass using NMP to obtain an NMP solution of polyorganosiloxane (referred to as polymer (PSQ-1)).

[0124] 4. Synthesis of styrene-maleimide copolymer [Synthesis Example 32] Under nitrogen, 5.00 g of compound (M-1), 1.05 g of compound (M-2), 4.80 g of compound (M-3), and 2.26 g of compound (M-4) were added to a 100 mL two-neck flask as polymerization monomers, 0.39 g of 2,2'-azobis(2,4-dimethylvaleronitrile) as a radical polymerization initiator, 0.39 g of 2,4-diphenyl-4-methyl-1-pentene as a chain transfer agent, and 52.5 mL of N-methyl-2-pyrrolidone (NMP) as a solvent, and polymerization was carried out for 6 hours at 70 °C. After reprecipitation in methanol, the precipitate was filtered and dried under vacuum at room temperature for 8 hours to obtain the target polymer (referred to as polymer (MI-1)).

[0125] 5. Polyamide Synthesis [Synthesis Example 33] The synthesis was carried out with reference to the method described in the reference document (Journal of Polymer Science: Polymer Chemistry Edition 1975, Vol. 13, 1691-1698). 100 parts by mole of compound (D-1) as a biisomaleimide and 100 parts by mole of compound (DB-18) as a diamine compound were dissolved in N-methyl-2-pyrrolidone (NMP), and the reaction was carried out at room temperature for 6 hours to obtain a solution containing 15% by mass of polyamide (referred to as polymer (pa-1)).

[0126] <Evaluation as a polymer> Example 1: Evaluation of residual amine and storage stability 1. Evaluation of residual amines The solution of the polymer (PAA-1) obtained in Synthesis Example 1 was dropped into acetone to precipitate the polymer. A portion of the supernatant was removed and evaluated by liquid chromatography (LC). If a peak of the diamine used as the raw material was observed, it was rated as "present," and if not, it was rated as "absent." As a result, the residual amine peak in Example 1 was "absent."

[0127] 2. Evaluation of storage stability The storage stability of the solution of polymer (PAA-1) obtained in Synthesis Example 1 was evaluated based on the rate of change ([(D2-D1) / D1)] x 100 (%)) between the solution viscosity D1 immediately after preparation of the polymer solution and the solution viscosity D2 after storage at room temperature for 7 days. A viscosity change rate of 5% or more was evaluated as "poor (×)," and a viscosity change rate of less than 5% was evaluated as "good (○)." As a result, the storage stability of Example 1 was evaluated as "good (○)."

[0128] [Reference example 1] The residual amine content and storage stability were evaluated in the same manner as in Example 1, except that the polymer was changed as shown in Table 3. The results are shown in Table 3. [Table 3]

[0129] As shown in Table 3, polymer (PAA-1) had less residual amine than polymer (pa-1), which is a polyamide, and also had good storage stability as a solution.

[0130] <Preparation and Evaluation of Liquid Crystal Alignment Agent> [Example 2: Rubbed FFS-type liquid crystal display element] 1. Preparation of Liquid Crystal Alignment Agent The solution of the polymer (PAA-2) obtained in Synthesis Example 2 was diluted with NMP and butyl cellosolve (BC) to obtain a solution with a solvent composition of NMP / BC=80 / 20 (mass ratio) and a solid content of 3.5 mass %. This solution was filtered through a filter with a pore size of 0.2 μm to prepare a liquid crystal alignment agent (AL-1).

[0131] 2. Fabrication of FFS-type LCD elements using the rubbing method A glass substrate (referred to as the first substrate) with a flat electrode (bottom electrode), an insulating layer, and a comb-shaped electrode (top electrode) laminated in this order on one side thereof, and a glass substrate (referred to as the second substrate) without an electrode, were prepared. Next, a liquid crystal alignment agent (AL-1) was applied to the electrode-formed surface of the first substrate and one side of the second substrate using a spinner and heated (pre-baked) on a hot plate at 110°C for 3 minutes. This was then dried (post-baked) for 30 minutes in a nitrogen-purged oven at 230°C to form a coating film with an average thickness of 0.08 μm. The coating film surface was then rubbed using a rubbing machine equipped with a roll wrapped around a rayon cloth at a roll rotation speed of 1000 rpm, a stage movement speed of 3 cm / sec, and a pile depth of 0.3 mm. This was followed by ultrasonic cleaning in ultrapure water for 1 minute and then drying in a clean oven at 100°C for 10 minutes to obtain a pair of substrates with liquid crystal alignment films. Next, a pair of substrates with liquid crystal alignment films were screen-printed with an epoxy resin adhesive containing 3.5 μm diameter aluminum oxide spheres, leaving a liquid crystal injection port at the edge of the surface where the liquid crystal alignment film was formed. The substrates were then stacked and pressed together, and the adhesive was thermally cured at 150°C for 1 hour. Next, negative liquid crystal (MLC-6608, manufactured by Merck) was injected into the gap between the pair of substrates through the liquid crystal injection port, and the liquid crystal injection port was then sealed with an epoxy adhesive. To eliminate flow alignment during liquid crystal injection, the substrates were heated to 120°C and then slowly cooled to room temperature to produce a liquid crystal cell. When stacking the pair of substrates, the rubbing directions of each substrate were antiparallel.

[0132] 3. Evaluation of liquid crystal alignment The liquid crystal cell manufactured in 2 above was set to a 27,000 cd / m 2 The liquid crystal alignment was evaluated by the rate of change in retardation before and after backlight irradiation. First, the retardation of the liquid crystal display element manufactured in 2 above was measured using an Axoscan manufactured by Optoscience, and the rate of change in retardation α before and after backlight irradiation was calculated using the following formula (z-1). The smaller the rate of change α, the better the liquid crystal alignment. A rate of change α of 1% or less was evaluated as "good (○)," a rate of change α between 1% and 2% was evaluated as "fair (△)," and a rate of change α greater than 2% was evaluated as "poor (×)." α=Δθ / θ1 …(z-1) (In formula (z-1), Δθ represents the difference in retardation before and after irradiation, and θ1 represents the retardation value before irradiation.) As a result, the liquid crystal alignment property of this example was evaluated as "good (◯)".

[0133] 4. Initial VHR Assessment The liquid crystal cell manufactured in 2 above was placed in an oven at 60°C, and then the voltage holding ratio (VHR) was measured under conditions of 1V and 1670msec using a VHR measuring device "VHR-1" manufactured by Toyo Corporation. The evaluation criteria were "good (○)" if the VHR was higher than 70%, "fair (△)" if it was 70% or less and 60% or more, and "poor (×)" if it was less than 60%. As a result, the initial VHR of this example was evaluated as "good (○)".

[0134] 5. Evaluation of VHR reliability The reliability (VHR reliability) of the liquid crystal cell manufactured in 2 above was evaluated based on the voltage holding ratio. The evaluation was performed as follows. First, a voltage of 1 V was applied to the liquid crystal cell for 60 microseconds, and then the voltage holding ratio (VHR1) was measured 1670 milliseconds after the application was removed. Next, the liquid crystal cell was irradiated with CCFL (backlight) at 60°C for one week, and then left to cool naturally to room temperature. After cooling, a voltage of 1 V was applied to the liquid crystal cell for 60 microseconds, and then the voltage holding ratio (VHR2) was measured 1670 milliseconds after the application was removed. The measurement device used was a VHR measuring device "VHR-1" manufactured by Toyo Corporation. The rate of change in VHR (ΔVHR) at this time was calculated as the difference between VHR1 and VHR2 (ΔVHR = VHR1 - VHR2), and VHR reliability was evaluated based on ΔVHR. If ΔVHR was less than 15%, it was judged as "good (○)", if it was between 15% and 20% it was judged as "fair (△)", and if it was more than 20%, it was judged as "poor (×)". As a result, in this example, the VHR reliability was "good (○)".

[0135] 6. Evaluation of film strength (rubbing resistance) The liquid crystal alignment agent (AL-1) prepared in 1 above was applied to a glass substrate using a spinner and heated (pre-baked) on a hot plate at 110°C for 3 minutes. The substrate was then dried (post-baked) for 30 minutes in a nitrogen-purged oven at 230°C to form a coating film with an average thickness of 0.08 μm. The haze value of this coating film was measured using a haze meter. The coating film was then rubbed five times using a rubbing machine equipped with a roll wrapped around a cotton cloth at a roll rotation speed of 1000 rpm, a stage movement speed of 3 cm / sec, and a pile depth of 0.3 mm. The haze value of the liquid crystal alignment film was then measured using a haze meter, and the difference from the haze value before and after rubbing (haze change) was calculated. If the haze value of the film before rubbing is Hz1 (%) and the haze value of the film after rubbing is Hz2 (%), the haze change is expressed by the following formula (z-2): Haze change value (%) = Hz2 - Hz1 ... (z-2) A haze change value of the liquid crystal alignment film of less than 0.5 was evaluated as "best (◎)", a haze change value of 0.5 or more but less than 1.0 was evaluated as "good (○)", a haze change value of 1.0 or more but less than 1.5 was evaluated as "fair (△)", and a haze change value of more than 1.5 was evaluated as "poor (×)". If the haze change value is 1.5 or less (more preferably less than 1.0, even more preferably less than 0.5), it can be said that the film strength is sufficiently high and the rubbing resistance is high, that is, the mechanical properties of the film are good. As a result, in this example, the film strength was evaluated as "good (○)".

[0136] 7. Evaluation of film strength (tapping test resistance) The liquid crystal cell manufactured in 2 above was evaluated for its resistance to keystroke tests. The evaluation was performed as follows. First, the liquid crystal cell was observed under a polarizing microscope with crossed Nicols, and the number of bright spots was counted. Next, the liquid crystal cell was fixed on a fixed plate, and a keystroke rod was moved up and down to apply a repeated load to the liquid crystal cell. The load was 250 gf, the number of repetitions was 100,000, and the speed was 10 Hz / sec. After keystrokes, the liquid crystal cell was observed again, and the number of bright spots was counted. If the difference in the number of bright spots before and after keystrokes was less than 5, it was evaluated as "best (◎)," if it was 5 to 10, it was evaluated as "good (○)," if it was 10 to 50, it was evaluated as "fair (△)," and if it was 50 or more, it was evaluated as "poor (×)." If the difference in the number of bright spots was less than 10 (more preferably less than 5), it can be said that the mechanical strength of the film against keystrokes was good. As a result, in this example, the film strength was evaluated as "good (○)."

[0137] [Examples 2 to 15 and Comparative Examples 2 and 3] A liquid crystal alignment agent was prepared in the same manner as in Example 2, except that the composition of the liquid crystal alignment agent was changed as shown in Table 4. Furthermore, using the obtained liquid crystal alignment agent, an FFS-type liquid crystal cell was produced by a rubbing method in the same manner as in Example 2, and various evaluations were carried out. The results are shown in Table 4. In Examples 3, 4, 7, and 12 to 15, two types of polymers were used as the polymer component. In Table 4, the numerical values ​​in the polymer column represent the blending ratio (parts by mass) of the solid content of each polymer relative to 100 parts by mass of the total amount of the polymer components used in preparing the liquid crystal alignment agent.

[0138] [Table 4]

[0139] As shown in Table 4, Examples 2 to 15, which used a liquid crystal alignment agent containing polymer [A], showed good or best results in film strength, especially in the keystroke test durability, compared to Comparative Examples 2 and 3, which used a liquid crystal alignment agent not containing polymer [A]. Furthermore, Examples 2 to 15 also showed good liquid crystal alignment properties, initial VHR, and VHR reliability.

[0140] [Example 16: Optical FFS type liquid crystal display element] 1. Preparation of Liquid Crystal Alignment Agent A solution containing 30 parts by mass of the polymer (PAA-15) obtained in Synthesis Example 15 and a solution containing 70 parts by mass of the polymer (paa-2) obtained in Synthesis Example 18 were mixed and diluted with NMP and BC to obtain a solution with a solvent composition of NMP / BC=80 / 20 (mass ratio) and a solids concentration of 3.5% by mass. This solution was filtered through a filter with a pore size of 0.2 μm to prepare a liquid crystal aligning agent (AL-17).

[0141] 2. Fabrication of FFS-type LCD elements using the photoalignment method A first substrate and a second substrate were prepared similarly to those in Example 1. Next, a liquid crystal alignment agent (AL-17) was applied to the electrode-forming surface of the first substrate and one of the substrate surfaces of the second substrate using a spinner, and heated (pre-baked) on a hot plate at 80°C for 1 minute. Thereafter, the substrate was dried (post-baked) for 30 minutes in an oven at 230°C with the interior replaced with nitrogen, forming a coating film with an average film thickness of 0.1 μm. The resulting coating film was irradiated with 1,000 J / m of linearly polarized ultraviolet light containing a 254 nm emission line using an Hg-Xe lamp. 2 The coating film was then irradiated with light from the normal direction of the substrate to perform a photo-alignment treatment. The irradiation dose was measured using an actinometer measuring at a wavelength of 254 nm. The photo-aligned coating film was then heat-treated in a clean oven at 230°C for 30 minutes to form a liquid crystal alignment film. Next, for one of the pair of substrates on which the liquid crystal alignment film was formed, an epoxy resin adhesive containing 3.5 μm diameter aluminum oxide spheres was applied by screen printing to the outer edge of the surface having the liquid crystal alignment film. The substrates were then superimposed and pressed together so that the projection directions of the polarization axes on the substrate surfaces during light irradiation were antiparallel, and the adhesive was thermally cured at 150°C for 1 hour. Next, negative liquid crystal (MLC-6608, manufactured by Merck) was filled between the pair of substrates through the liquid crystal injection port, which was then sealed with an epoxy adhesive to obtain a liquid crystal cell. Furthermore, to remove flow alignment during liquid crystal injection, the cell was heated at 120°C and then slowly cooled to room temperature. The above series of operations was also performed with a post-baking UV irradiation dose of 100 to 10,000 J / m. 2 Three or more liquid crystal cells with different UV exposure doses were manufactured by changing the exposure dose within the range of , and the liquid crystal cell with the exposure dose that showed the best alignment characteristics (optimum exposure dose) was used for the following evaluation of liquid crystal alignment, initial VHR, VHR reliability, and film strength.

[0142] 3. Evaluation The liquid crystal cells manufactured in 2 above were evaluated for liquid crystal alignment, initial VHR, and VHR reliability in the same manner as in Example 2. In addition, the film strength was evaluated using a liquid crystal alignment agent (AL-17) in the same manner as in Example 2. The evaluation results are shown in Table 5.

[0143] [Examples 17 to 23, Comparative Examples 4 and 5] A liquid crystal alignment agent was prepared in the same manner as in Example 16, except that the composition of the liquid crystal alignment agent was changed as shown in Table 5. Furthermore, using the obtained liquid crystal alignment agent, an FFS-type liquid crystal cell was produced by a photoalignment method in the same manner as in Example 16, and various evaluations were performed. The results are shown in Table 5. In Example 23 and Comparative Example 5, N,N,N',N'-tetraglycidyl-4,4'-diaminodiphenylmethane (referred to as compound (N-1)) was blended as an additive component together with the polymer component. In Table 5, the values ​​in the "Polymer" column represent the blending ratio (parts by mass) of the solid content of each polymer relative to 100 parts by mass of the total solid content (polymer component and additive component) used in the preparation of the liquid crystal alignment agent. The values ​​in the "Additive" column represent the blending ratio (parts by mass) of the solid content of compound (N-1) relative to 100 parts by mass of the total solid content (polymer component and additive component) used in the preparation of the liquid crystal alignment agent.

[0144] [Table 5]

[0145] As shown in Table 5, Examples 16 to 23, which used a liquid crystal alignment agent containing polymer [A], showed good or best results in film strength, especially in the keystroke test resistance, compared to Comparative Examples 4 and 5, which used a liquid crystal alignment agent not containing polymer [A], and had well-balanced performance in terms of liquid crystal alignment property, initial VHR, and VHR reliability.

[0146] [Example 24: PSA type liquid crystal display element] 1. Preparation of Liquid Crystal Alignment Agent A solution containing 5 parts by mass of the polymer (PSQ-1) obtained in Synthesis Example 31 and a solution containing 95 parts by mass of the polymer (PI-3) obtained in Synthesis Example 27 were mixed and diluted with NMP and BC to obtain a solution with a solvent composition of NMP / BC=50 / 50 (mass ratio) and a solids concentration of 3.5% by mass. This solution was filtered through a filter with a pore size of 0.2 μm to prepare a liquid crystal aligning agent (AL-27).

[0147] 2. Preparation of Liquid Crystal Composition 5% by mass of a liquid crystal compound represented by the following formula (L1-1) and 0.3% by mass of a photopolymerizable compound represented by the following formula (L2-1) were added to 10 g of nematic liquid crystal (MLC-6608, manufactured by Merck) and mixed to obtain liquid crystal composition LC1. [ka]

[0148] 3. Manufacturing of PSA type liquid crystal display elements The liquid crystal alignment agent (AL-27) prepared above was applied to the transparent electrode surface of a glass substrate with an ITO transparent electrode using a spinner. After pre-baking for 1 minute on a hot plate at 80°C, the substrate was heated in a nitrogen-purged oven at 200°C for 1 hour to remove the solvent, forming a 0.08 μm-thick coating (liquid crystal alignment film). This coating film was then rubbed using a rubbing machine equipped with a roll wrapped around a rayon cloth at a roll rotation speed of 400 rpm, a stage movement speed of 3 cm / sec, and a pile depth of 0.1 mm. The substrate was then ultrasonically cleaned in ultrapure water for 1 minute and then dried in a clean oven at 100°C for 10 minutes to obtain a substrate with a liquid crystal alignment film. This process was repeated to obtain a pair (two substrates) with a liquid crystal alignment film. Note that this rubbing treatment was weak, intended to suppress liquid crystal collapse and facilitate alignment division. An epoxy resin adhesive containing 3.5 μm diameter aluminum oxide spheres was applied by screen printing to the outer periphery of the surface of one of the substrates bearing the liquid crystal alignment film, and then the liquid crystal alignment film surfaces of the pair of substrates were placed facing each other, overlapped, and pressed together, followed by heating at 150°C for 1 hour to thermally cure the adhesive. Next, liquid crystal composition LC1 was filled into the gap between the substrates through the liquid crystal injection port, which was then sealed with an epoxy adhesive. To prevent flow alignment during liquid crystal injection, the resulting mixture was heated at 150°C for 10 minutes and then slowly cooled to room temperature. Next, an AC voltage of 10 V at a frequency of 60 Hz was applied between the electrodes of the obtained liquid crystal cell, and while the liquid crystal was in a driving state, ultraviolet rays of 50,000 J / m were irradiated using an ultraviolet irradiation device that used a metal halide lamp as a light source. 2The irradiation amount was measured using an actinometer measuring at a wavelength of 365 nm as a reference. A PSA liquid crystal cell was thus produced.

[0149] 4. Evaluation The liquid crystal cells produced in 3 above were evaluated for liquid crystal alignment, initial VHR, VHR reliability, and film strength in the same manner as in Example 2. Table 6 shows the evaluation results.

[0150] Comparative Example 6 A liquid crystal alignment agent was prepared in the same manner as in Example 24, except that the composition of the liquid crystal alignment agent was changed as shown in Table 6. In addition, a PSA-type liquid crystal cell was produced using the obtained liquid crystal alignment agent in the same manner as in Example 24, and various evaluations were performed. The evaluation results are shown in Table 6. In Table 6, the numerical values ​​in the polymer column represent the blending ratio (parts by mass) of the solid content of each polymer relative to 100 parts by mass of the total amount of the polymer components used in preparing the liquid crystal alignment agent.

[0151] [Table 6]

[0152] As shown in Table 6, Example 24, which used a liquid crystal alignment agent containing polymer [A], was evaluated as good in liquid crystal alignment property, initial VHR, and VHR reliability, and was evaluated as best in film strength. In contrast, Comparative Example 6, which used a liquid crystal alignment agent not containing polymer [A], was evaluated as "fair" in film strength (rubbing resistance) and "poor" in film strength (tapping test resistance).

[0153] [Example 25: Optical VA type liquid crystal display element] 1. Preparation of Liquid Crystal Alignment Agent A solution containing 30 parts by mass of the polymer (MI-1) obtained in Synthesis Example 32 and 70 parts by mass of the polymer (PAA-14) obtained in Synthesis Example 14 was mixed and diluted with NMP and BC to obtain a solution with a solvent composition of NMP / BC=80 / 20 (mass ratio) and a solids concentration of 3.5% by mass. This solution was filtered through a filter with a pore size of 0.2 μm to prepare a liquid crystal aligning agent (AL-29).

[0154] 2. Manufacturing of optical VA type liquid crystal display elements The liquid crystal alignment agent (AL-29) prepared above was applied to the transparent electrode surface of a glass substrate with a transparent electrode made of an ITO film using a spinner, and pre-baked on a hot plate at 80°C for 1 minute. It was then heated at 230°C for 1 hour in an oven with the interior replaced with nitrogen, forming a coating film with a thickness of 0.1 μm. Next, the surface of this coating film was irradiated with polarized ultraviolet light at 1,000 J / m², including a 313 nm emission line, using an Hg-Xe lamp and a Glan-Taylor prism. 2 The substrate was irradiated with light from a direction tilted by 40° from the normal to the substrate to impart liquid crystal alignment ability. The same procedure was repeated to prepare a pair (two substrates) having a liquid crystal alignment film. An epoxy resin adhesive containing 3.5 μm diameter aluminum oxide spheres was screen-printed onto the outer periphery of the surface of one of the substrates bearing the liquid crystal alignment film. The pair of substrates were then placed with the liquid crystal alignment film surfaces facing each other and pressed together so that the UV light axes of the substrates were antiparallel to each other. The adhesive was then thermally cured at 150°C for 1 hour. Next, negative liquid crystal (MLC-6608, manufactured by Merck) was injected into the gap between the substrates through the liquid crystal injection port, which was then sealed with an epoxy adhesive. To eliminate flow alignment during liquid crystal injection, the substrate was heated to 130°C and then slowly cooled to room temperature.

[0155] 3. Evaluation The liquid crystal cells produced in 2 above were evaluated for liquid crystal alignment, initial VHR, VHR reliability, and film strength in the same manner as in Example 2. Table 7 shows the evaluation results.

[0156] Comparative Example 7 A liquid crystal alignment agent was prepared in the same manner as in Example 25, except that the composition of the liquid crystal alignment agent was changed as shown in Table 7. In addition, an optical VA-type liquid crystal cell was produced using the obtained liquid crystal alignment agent in the same manner as in Example 25, and various evaluations were performed. The results are shown in Table 7. In Table 7, the numerical values ​​in the polymer column represent the blending ratio (parts by mass) of the solid content of each polymer relative to 100 parts by mass of the total amount of the polymer components used in preparing the liquid crystal alignment agent.

[0157] [Table 7]

[0158] As shown in Table 7, Example 25, which used a liquid crystal alignment agent containing polymer [A], was evaluated as good in liquid crystal alignment, initial VHR, and VHR reliability, and was evaluated as best in film strength. In contrast, Comparative Example 7, which used a liquid crystal alignment agent not containing polymer [A], was evaluated as "fair" in film strength (rubbing resistance) and "poor" in film strength (tapping test resistance).

[0159] From the above results, it has become clear that a liquid crystal alignment agent containing a polymer having the partial structure (a) in its main chain can provide a liquid crystal element with good liquid crystal alignment properties, a high voltage holding ratio, and excellent reliability, as well as high cured film strength.

Claims

1. A liquid crystal aligning agent comprising a polymer [A] having a partial structure (a) represented by the following formula (1) in its main chain: 【Chemistry 1】 (In formula (1), R １ and R ２ are each independently -C(R ５ ) (R ６ )-, -O-, -S-, -CO-, -COO-, -NR ７ -, -NR ７ -NR ８ -, -NR ７ -CO-O-, -NR ７ -CO-NR ８ -, an aromatic hydrocarbon ring, an aromatic heterocycle, or a nitrogen-containing non-aromatic heterocycle, which is a divalent group bonded to the carbonyl group in formula (1). ３ and R ４ are each independently a hydrogen atom, a halogen atom, or an alkyl group having 1 to 3 carbon atoms, or R ３ and R ４ and are combined together to form R ３ and the carbon to which R ４ represents a ring structure formed together with the carbon to which R is attached. ５ and R ６ are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 8 carbon atoms, an alkenyl group having 2 to 8 carbon atoms, or an alkoxy group having 1 to 8 carbon atoms. ７ and R ８ are each independently a hydrogen atom or a monovalent organic group. "*" represents a bond.

2. The liquid crystal aligning agent according to claim 1 , wherein the polymer [A] contains a structural unit derived from a diamine having the partial structure (a).

3. The liquid crystal aligning agent according to claim 2 , wherein the diamine is a compound represented by the following formula (2): 【Chemistry 2】 (In formula (2), A １ and A ２ are each independently a single bond, a divalent alicyclic group, or a divalent aromatic ring group. m1 is an integer of 1 to 3. R １ , R ２ , R ３ and R ４ has the same meaning as in formula (1). When m1 is 2 or 3, a plurality of R １ ~R ４ are the same or different.)

4. The liquid crystal aligning agent according to claim 1 , wherein the polymer [A] contains a structural unit derived from a tetracarboxylic acid derivative having the partial structure (a).

5. The liquid crystal aligning agent according to claim 4, wherein the tetracarboxylic acid derivative is at least one selected from the group consisting of a compound represented by the following formula (3) and a compound represented by the following formula (4): 【Transformation 3】 (In formula (3) and formula (4), A ３ and A ４ are each independently a trivalent aromatic ring group or aliphatic ring group. m2 is an integer of 1 to 3. n1 and n2 are each independently an integer of 1 to 3. R １ , R ２ , R ３ and R ４ has the same meaning as in formula (1). When m2 is 2 or 3, a plurality of R １ ~R ４ are the same or different.)

6. The liquid crystal aligning agent according to claim 1 , wherein the polymer [A] is at least one selected from the group consisting of polyamic acid, polyamic acid ester, and polyimide.

7. The liquid crystal aligning agent according to claim 6 , wherein the polymer [A] contains a structural unit derived from an alicyclic tetracarboxylic dianhydride.

8. The liquid crystal aligning agent according to claim 1 , further comprising a polymer [Q] that does not have the partial structure (a).

9. A liquid crystal alignment film formed by the liquid crystal aligning agent according to any one of claims 1 to 8.

10. A liquid crystal device comprising the liquid crystal alignment film according to claim 9 .

11. A polyamic acid, a polyamic acid ester, and a polyimide each having a partial structure represented by the following formula (1) in the main chain: 【Chemistry 4】 (In formula (1), R １ and R ２ are each independently -C(R ５ ) (R ６ )-, -O-, -S-, -CO-, -COO-, -NR ７ -, -NR ７ -NR ８ -, -NR ７ -CO-O-, -NR ７ -CO-NR ８ -, an aromatic hydrocarbon ring, an aromatic heterocycle, or a nitrogen-containing non-aromatic heterocycle, which is a divalent group bonded to the carbonyl group in formula (1). ３ and R ４ are each independently a hydrogen atom, a halogen atom, or an alkyl group having 1 to 3 carbon atoms, or R ３ and R ４ and are combined together to form R ３ and the carbon to which R ４ represents a ring structure formed together with the carbon to which R is attached. ５ and R ６ are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 8 carbon atoms, an alkenyl group having 2 to 8 carbon atoms, or an alkoxy group having 1 to 8 carbon atoms. ７ and R ８ are each independently a hydrogen atom or a monovalent organic group. "*" represents a bond.

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