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

Abstract

This invention provides a liquid crystal alignment agent, a liquid crystal alignment film, and a liquid crystal element. The liquid crystal alignment agent comprises a polymer (P) containing structural units (U1), (U2), and (U3) within the same molecule. Structural unit (U1): a structural unit derived from a diamine having a partial structure represented by formula (1). Structural unit (U2): a structural unit derived from a Y (-(CH2)) compound having a partial structure. n Structural units of diamines (excluding structural units (U1) and (U3)). Structural unit (U3): derived from structural units of diamines having a partial structure represented by formula (2). In formula (1), A 1 and A 2 It is a trivalent aromatic cyclic group. B 1 -NR 1 - etc. In equation (2), X 1 It is a monovalent thermally detachable radical. R 4 For "-C(R) 7 (R) 8 )-” etc. R 5 For "-C(R) 7 (R) 8 )-"wait.

Description

Technical Field

[0001] This invention relates to a liquid crystal alignment agent, a liquid crystal alignment film, and a liquid crystal element. Background Technology

[0002] Liquid crystal elements (LCDs) are widely used in televisions, mobile devices, and various monitors. With this increasing versatility, the demand for higher quality LCDs is growing, leading to improvements in driving methods and element structures, as well as improvements to the liquid crystal alignment film, one of the constituent materials of LCDs.

[0003] When considering the application of the rubbing method to liquid crystal alignment films or to suppress yield reduction in the manufacture of liquid crystal elements, the organic films formed using liquid crystal alignment agents are required to have high adhesion and abrasion resistance (hereinafter also referred to as "film strength").

[0004] Therefore, various techniques for improving the strength of liquid crystal alignment films have been proposed (for example, see Patent Document 1). Patent Document 1 discloses a crosslinking compound in which the liquid crystal alignment agent contains polyimide or a polyimide precursor, as well as a low-molecular-weight compound that improves the hardness of the liquid crystal alignment film.

[0005] [Existing Technical Documents]

[0006] [Patent Literature]

[0007] [Patent Document 1] International Publication No. 2020 / 171128 Summary of the Invention

[0008] [The problem the invention aims to solve]

[0009] To meet the increasingly stringent quality requirements of recent years, it is crucial that the liquid crystal alignment film possesses excellent film strength and that the liquid crystal element exhibits good electrical properties. In a liquid crystal element, if charge accumulates within the liquid crystal cells, it will be perceived by the observer as image retention (direct current (DC) retention), degrading the display quality. Therefore, one of the required electrical characteristics for liquid crystal elements is rapid dissipation of accumulated charge and easy disappearance of DC retention. However, it is difficult to maintain good liquid crystal alignment while simultaneously possessing a balance of film strength and electrical properties, leaving room for further improvement in liquid crystal alignment agents and liquid crystal elements.

[0010] The present invention was made in view of the aforementioned issues, and one of its objectives is to provide a liquid crystal alignment agent that can produce a liquid crystal alignment film with high film strength while exhibiting good liquid crystal alignment properties, and can also produce a liquid crystal element with excellent electrical properties.

[0011] [Technical means to solve the problem]

[0012] The present invention provides liquid crystal alignment agents, liquid crystal alignment films, and liquid crystal elements.

[0013] [1] A liquid crystal alignment agent comprising a polymer (P) containing structural units (U1), (U2) and (U3) within the same molecule.

[0014] Structural unit (U1): a structural unit derived from a diamine having a partial structure represented by the following formula (1);

[0015] Structural unit (U2): A structural unit derived from a diamine having the following partial structure Y (except for the structural unit (U1) and the following structural unit (U3)).

[0016] Structural unit (U3): a structural unit derived from a diamine having a partial structure represented by the following formula (2);

[0017] Partial structure Y: The structure represented, or Any methylene group in the represented structure is replaced by -O-, -S-, -CO-O-, or -NR. 9 -、-NR 10 -CO-、-NR 10 -CO-O- or -NR 10 -CO-NR 11 - The structure formed by substitution (where n is an integer from 2 to 20; R 9 It is a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms; R 10 and R 11 Each can be independently a hydrogen atom or a monovalent organic group; -O-, -S-, -CO-O-, -NR 9 -、-NR 10 -CO-、-NR 10 -CO-O- and -NR 10 -CO-NR 11 - They are not adjacent to each other; "This refers to a bond formed by a single or divalent organogroup to a primary amino group."

[0018] [Chemistry 1]

[0019]

[0020] (In formula (1), A) 1 and A 2 Each is independently a trivalent aromatic cyclic group; B 1 It is a divalent aromatic heterocyclic group or -NR 1 -; in B 1In the case of a divalent aromatic heterocyclic group, R 2 and R 3 Each can be independently a hydrogen atom or a monovalent organic group, or represent R. 2 With R 3 Combine with A 1 Divalent aromatic heterocyclic groups and A 2 A ring structure formed together; in B 1 For -NR 1 In the case of -R 1 R 2 and R 3 For the following (i) or (ii);

[0021] (i)R 1 It is a hydrogen atom or a monovalent organic group; R 2 and R 3 Each can be independently a hydrogen atom or a monovalent organic group, or represent R. 2 With R 3 Combine with A 1 A 2 and A 1 and A 2 The ring structure formed by the bonded nitrogen atoms;

[0022] (ii)R 1 and R 2 Each can be independently a hydrogen atom or a monovalent organic group, or represent R. 1 With R 2 Combine with A 1 and R 1 and A 1 The ring structure formed by the bonded nitrogen atoms; R 3 It can be a hydrogen atom or a monovalent organic group;

[0023] “ "Indicates a bond"

[0024] [Chemistry 2]

[0025]

[0026] (In formula (2), X) 1 It is a monovalent thermally degraded radical; d is 1 or 2; when d is 1, R 4 For "-C(R) 7 (R) 8 )-” or ">C=NR 20 "When d is 2, R 4 for" "(in," "Indicates a bond with a nitrogen atom); R 20It is a hydrogen atom or a monovalent organic group; R 5 For "-C(R) 7 (R) 8 )-”, or a substituted or unsubstituted divalent alicyclic group; R 7 and R 8 Each can be a hydrogen atom or a substituent independently; R 6 It is a hydrogen atom, or a substituted or unsubstituted monovalent aliphatic hydrocarbon group; a is 1 or 2; b is 0 or 1; c is 0 or 1; where a + b + c = 2; in R 7 In the case of two Rs, 7 Same or different; in R 8 In the case of two Rs, 8 Same or different; "Indicates a bond".

[0027] [2] A liquid crystal alignment film is formed using a liquid crystal alignment agent as described in [1].

[0028] [3] A liquid crystal element comprising a liquid crystal alignment film as described in [2].

[0029] [The effects of the invention]

[0030] The liquid crystal alignment agent of the present invention provides a liquid crystal alignment film that exhibits good liquid crystal alignment while maintaining high film strength. Furthermore, the liquid crystal alignment agent of the present invention provides a liquid crystal element with excellent electrical properties. Detailed Implementation

[0031] The following provides a detailed description of matters related to the embodiments of this disclosure.

[0032] In this specification, the numerical range indicated by “~” refers to the values ​​before and after the “~” as lower and upper limits, respectively. A “structural unit” is a unit that primarily constitutes the main chain structure, and contains at least two units within the main chain structure. Typically, a structural unit is a monomer unit. However, substances formed by reacting a monomer unit having a reactive group with a compound having a functional group capable of reacting with said reactive group are also included in the term “structural unit.”

[0033] In this specification, "hydrocarbon group" refers to chain-like hydrocarbon groups, alicyclic hydrocarbon groups, and aromatic hydrocarbon groups. "Chain-like hydrocarbon group" refers to a straight-chain hydrocarbon group or a branched hydrocarbon group that contains only a chain structure and no cyclic structure. The chain-like hydrocarbon group can be saturated or unsaturated. "Alicyclic hydrocarbon group" refers to a hydrocarbon group that contains only an alicyclic hydrocarbon structure as its ring structure and does not contain an aromatic ring structure. The alicyclic hydrocarbon group does not necessarily need to contain only an alicyclic hydrocarbon structure; it may also include groups with a chain structure in a portion thereof. "Aromatic hydrocarbon group" refers to a hydrocarbon group that contains an aromatic ring structure as its ring structure. The aromatic hydrocarbon group does not necessarily need to contain only an aromatic ring structure; it may also contain a chain structure or an alicyclic hydrocarbon structure in a portion thereof. "Aromatic ring" refers to aromatic hydrocarbon rings and aromatic heterocycles. "Aliphatic hydrocarbon group" refers to both chain-like hydrocarbon groups and alicyclic hydrocarbon groups. "Organic group" refers to a group of atoms formed by removing any hydrogen atom from a carbon-containing compound (i.e., an organic compound).

[0034] The term "main chain" of a polymer refers to the "stem" portion of the chain containing the longest atoms in the polymer. The "stem" portion may contain ring structures. For example, "having a specific structure in the main chain" means that the specific structure constitutes part of the main chain. The term "side chain" refers to a portion that branches off from the polymer's "stem." "(meth)acrylate" is a term encompassing both acrylate and methacrylate groups, and "(meth)acryloyl" is a term encompassing both acryloyl and methacryloyl groups.

[0035] Liquid crystal alignment agent

[0036] The liquid crystal alignment agent disclosed herein contains a polymer (hereinafter also referred to as "polymer (P)") comprising specific structural units. The polymer (P) contained in the liquid crystal alignment agent of this disclosure, and other components that may be arbitrarily formulated as needed, will be described below. Furthermore, unless otherwise specifically mentioned, each component may be used alone or in combination with two or more components.

[0037] <Polymer (P)>

[0038] Polymer (P) is a polymer that contains structural units (U1), (U2), and (U3) within the same molecule. The structural units contained in polymer (P) will be described in detail below.

[0039] • Structural unit (U1)

[0040] The structural unit (U1) is a structural unit derived from a diamine (hereinafter also referred to as “specific diamine (A)”) having a partial structure represented by the following formula (1).

[0041] [Chemistry 3]

[0042]

[0043] (In formula (1), A) 1 and A 2 Each is independently a trivalent aromatic cyclic group; B 1 It is a divalent aromatic heterocyclic group or -NR 1 -; in B 1 In the case of a divalent aromatic heterocyclic group, R 2 and R 3 Each can be independently a hydrogen atom or a monovalent organic group, or represent R. 2 With R 3 Combine with A 1 Divalent aromatic heterocyclic groups and A 2 A ring structure formed together; in B 1 For -NR 1 In the case of -R 1 R 2 and R 3 For example, (i) or (ii) below;

[0044] (i)R 1 It is a hydrogen atom or a monovalent organic group; R 2 and R 3 Each can be independently a hydrogen atom or a monovalent organic group, or represent R. 2 With R 3 Combine with A 1 A 2 and A 1 and A 2 The ring structure formed by the bonded nitrogen atoms;

[0045] (ii)R 1 and R 2 Each can be independently a hydrogen atom or a monovalent organic group, or represent R. 1 With R 2 Combine with A 1 and R 1 and A 1 The ring structure formed by the bonded nitrogen atoms; R 3 It can be a hydrogen atom or a monovalent organic group;

[0046] “ "Indicates a bond".

[0047] In the above equation (1), A is... 1 and A 2The trivalent aromatic cyclic group represented can include trivalent aromatic hydrocarbon groups and trivalent aromatic heterocyclic groups. Examples of trivalent aromatic heterocyclic groups include nitrogen-containing aromatic heterocyclic groups, oxygen-containing aromatic heterocyclic groups, and sulfur-containing aromatic heterocyclic groups, with nitrogen-containing aromatic heterocyclic groups being preferred. Furthermore, A 1 and A 2 The aromatic ring may also have substituents. Examples of such substituents include alkyl groups having 1 to 5 carbon atoms, halogen atoms (fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, etc.).

[0048] Regarding A 1 and A 2 Specific examples of the trivalent aromatic ring group, as trivalent aromatic hydrocarbon groups, include groups formed by removing any three hydrogen atoms bonded to the carbon atoms constituting a benzene ring, naphthalene ring, or anthracene ring; as trivalent nitrogen-containing aromatic heterocyclic groups, include groups formed by removing any three hydrogen atoms bonded to the carbon atoms constituting a pyrrole ring, pyridine ring, pyrimidine ring, pyridazine ring, or pyrazine ring; as trivalent oxygen-containing aromatic heterocyclic groups, include groups formed by removing any three hydrogen atoms bonded to the carbon atoms constituting a furan ring; and as trivalent sulfur-containing aromatic heterocyclic groups, include groups formed by removing any three hydrogen atoms bonded to the carbon atoms constituting a thiophene ring. From the viewpoint of simultaneously exhibiting good liquid crystal orientation and improving film strength and electrical properties, A... 1 and A 2 The trivalent aromatic ring group represented is preferably a trivalent aromatic hydrocarbon group, and more preferably a group formed by removing any three hydrogen atoms from a benzene ring.

[0049] In B 1 In the case of a divalent aromatic heterocyclic group, examples of divalent aromatic heterocyclic groups that combine with the components of A can be listed. 1 and A 2 The radicals are formed by removing any two hydrogen atoms from the carbon atom bonds of the aromatic heterocycles exemplified in the example. Among these, B is particularly effective in mitigating accumulated charge and improving electrical properties. 1 The divalent aromatic heterocyclic group represented is preferably a group formed by removing any two hydrogen atoms that are bonded to the carbon atoms constituting the pyrrole ring, furan ring, and thiophene ring.

[0050] In B 1 In the case of a divalent aromatic heterocyclic group, as R 2 and R 3 Examples of monovalent organic groups include alkyl groups with 1 to 3 carbon atoms, halogen atoms, and cyano groups. In this case, R... 2 and R 3 Preferably, it contains hydrogen atoms or alkyl groups having 1 to 3 carbon atoms, more preferably hydrogen atoms. In the representation of R... 2 With R 3 Combine with A1 Divalent aromatic heterocyclic groups and A 2 In the case of a ring structure formed together, examples of such ring structures include: carbazole ring structure, dibenzothiophene ring structure, dibenzofuran ring structure, etc.

[0051] From the perspective of further improvement of electrical properties, B 1 Preferred is -NR 1 -

[0052] In B 1 For -NR 1 In the case of -R 1 R 2 and R 3 For (i) or (ii). As R 1 R 2 and R 3 R is as described in (i) 1 The monovalent organic group represented is preferably a monovalent hydrocarbon group or a monovalent thermally detachable group having 1 to 10 carbon atoms. Examples of monovalent hydrocarbon groups having 1 to 10 carbon atoms include: monovalent chain hydrocarbon groups having 1 to 10 carbon atoms, monovalent alicyclic hydrocarbon groups having 3 to 10 carbon atoms, and monovalent aromatic hydrocarbon groups having 6 to 10 carbon atoms. Among these, alkyl, cyclohexyl, or phenyl groups having 1 to 6 carbon atoms are preferred, alkyl groups having 1 to 6 carbon atoms are more preferred, and alkyl groups having 1 to 3 carbon atoms are even more preferred.

[0053] As R 1 Examples of monovalent thermally detachable groups include: tert-butoxycarbonyl (Boc group), benzyloxycarbonyl, 1,1-dimethyl-2-haloethyloxycarbonyl, allyloxycarbonyl, 2-(trimethylsilyl)ethoxycarbonyl, and 9-fluorenylmethyloxycarbonyl (F-moc group). The Boc group is preferred in terms of its excellent thermal detachability and the reduction of the amount of detached structure remaining in the film.

[0054] In the case of (i), as R 2 and R 3 The monovalent organic group represented can be applied to the B... 1 R when it is a divalent aromatic heterocyclic group 2 and R 3 Explanation of the monovalent organic group represented.

[0055] In R 2 and R 3 R represents 2 With R 3 Combine with A 1 A 2 and A 1 and A 2In the case of a ring structure formed by the bonded nitrogen atoms, examples of such ring structures include: carbazole ring structure, 9-methylcarbazole ring structure, 9-ethylcarbazole ring structure, etc.

[0056] In R 1 R 2 and R 3 In the case of (ii), as R 1 The monovalent organic group represented can be applied to R in (i). 1 Explanation of the monovalent organic group represented.

[0057] As R 2 and R 3 The monovalent organic group represented can be applied to the B... 1 R when it is a divalent aromatic heterocyclic group 2 and R 3 Explanation of the monovalent organic group represented.

[0058] In R 1 and R 2 R represents 1 With R 2 Combine with A 1 and R 1 and A 1 In the case of a ring structure formed by the bonded nitrogen atoms, examples of such ring structures include: carbazole ring structure, indole ring structure, benzimidazole ring structure, indoline ring structure, etc.

[0059] In the case described in (ii), from the viewpoint of achieving improved electrical characteristics, R 1 R 2 and R 3 Preferably, each is an independent hydrogen atom or a monovalent organic group.

[0060] Regarding a preferred specific example of the partial structure represented by the aforementioned equation (1), as B 1 For -NR 1 Examples of this type of situation can be listed below, such as the partial structures represented by equations (1-1) to (1-7); as B 1 Examples of divalent aromatic heterocyclic groups include the partial structures represented by equations (1-8) to (1-13) below.

[0061] [Chemistry 4]

[0062]

[0063] (In equations (1-1) to (1-13), R) 1 and R 12 It can be a hydrogen atom or a monovalent organic group; "Indicates a bond".

[0064] In equations (1-8) and (1-11), R is used as... 12 The monovalent organic group represented can be applied to the R... 1 Explanation of the monovalent organic group represented.

[0065] The specific diamine (A) may have only one partial structure represented by formula (1) or more. From the viewpoint of ensuring the solubility of the polymer (P), one or two are preferred. The specific diamine (A) is preferably an aromatic diamine, wherein, it is preferably an aromatic diamine having a structure capable of introducing the partial structure represented by formula (1) into the main chain of the polymer (P). As specific examples of the specific diamine, compounds represented by formulas (A-1) to (A-11) can be listed. In addition, the specific diamine (A) may also have the partial structure represented by formula (1) and the partial structure Y. In terms of easily obtaining a liquid crystal alignment film with excellent liquid crystal alignment and electrical properties and further improved film strength by adjusting the type and amount of monomers when synthesizing the polymer (P), the specific diamine (A) is preferably without the partial structure Y.

[0066] [Chemistry 5]

[0067]

[0068] From the viewpoint of achieving further improvement in electrical properties, B in formula (1) is preferred as a specific diamine (A). 1 For -NR 1 - That is, preferably the compounds represented by formulas (A-1) to (A-7) and (A-11) respectively.

[0069] • Structural unit (U2)

[0070] Structural unit (U2) is a structural unit derived from a diamine (hereinafter also referred to as "specific diamine (B)") having the following partial structure Y. In addition, structural units corresponding to structural unit (U1) and structural units corresponding to structural unit (U3) are excluded.

[0071] Partial structure Y: The structure represented, or Any methylene group in the represented structure is replaced by -O-, -S-, -CO-O-, or -NR. 9 -、-NR 10 -CO-、-NR 10 -CO-O- or -NR 10 -CO-NR 11- The structure formed by substitution (where n is an integer from 2 to 20; R 9 It is a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms; R 10 and R 11 Each can be independently a hydrogen atom or a monovalent organic group; -O-, -S-, -CO-O-, -NR 9 -、-NR 10 -CO-、-NR 10 -CO-O- and -NR 10 -CO-NR 11 - They are not adjacent to each other; "This refers to a bond formed by a single or divalent organic group to a primary amino group."

[0072] In the aforementioned partial structure Y, n only needs to be 2 to 20. From the viewpoint of achieving improved film strength while exhibiting good liquid crystal alignment, n is preferably 3 or more, more preferably 4 or more, and even more preferably 5 or more. Furthermore, from the aforementioned viewpoint, n is preferably 14 or less, more preferably 12 or less, and even more preferably 10 or less.

[0073] As R 9 The monovalent hydrocarbon groups representing 1 to 10 carbon atoms can be applied using the R... 1 Explanation of the monovalent hydrocarbon groups representing 1 to 10 carbon atoms.

[0074] As R 10 and R 11 The monovalent organic group represented can be applied to the R... 1 Explanation of the monovalent organic group represented.

[0075] As The structure represented by the substitution of any methylene group with -O-, etc., is preferably formed by the substitution of any methylene group with -O-, -S-, -CO-O-, or -NR. 10 -CO- or -NR 10 -CO-NR 11 -A structure formed by substitution. Furthermore, from the viewpoint of improving liquid crystal orientation, it is more preferable that any methylene group is replaced by -O-, -NR. 10 -CO- or -NR 10 -CO-NR 11 The structure formed by substitution is preferably one in which any methylene group is replaced by -O- or -NR. 10 -CO-NR 11 - A structure formed by replacement.

[0076] The The structure represented by the substitution of any methylene group with -O- is more preferably a structure in which n is 3 or more and any two or more methylene groups are substituted with -O-, and even more preferably a structure in which n is 3 or more and The structure shown is formed by -O- substitution of the methylene groups at both ends.

[0077] A specific diamine (B) has primary amino groups at both ends of its main chain and a partial structure Y in the main chain. When synthesizing a polymer (P), the partial structure Y can be introduced into the main chain of the polymer (P) by using the specific diamine (B). Examples of specific diamines (B) include aliphatic diamines, alicyclic diamines, aromatic diamines, and diamino organosiloxanes. Specifically, compounds represented by formula (3) below can be listed as examples.

[0078] [Chemistry 6]

[0079]

[0080] (In formula (3), Y) 2 -(CH2) n - represents the structure, or -(CH2) n - Any methylene group in the structure represented by -O-, -S-, -CO-O-, -NR 9 -、-NR 10 -CO-、-NR 10 -CO-O- or -NR 10 -CO-NR 11 - The structure formed by substitution; n is an integer from 2 to 20; R 9 It is a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms; R 10 and R 11 Each can be independently a hydrogen atom or a monovalent organic group; -O-, -S-, -CO-O-, -NR 9 -、-NR 10 -CO-、-NR 10 -CO-O- and -NR 10 -CO-NR 11 - They are not adjacent to each other; A 3 and A 4 Each is independently a single bond, or a substituted or unsubstituted divalent aromatic cyclic group.

[0081] In the above equation (3), A is... 3 and A 4 The divalent aromatic cyclic group represented can be listed as one that will form the A. 1 and A 2The trivalent aromatic ring group is a group formed by removing any two hydrogen atoms from the carbon atom bond of the aromatic ring as listed in the description.

[0082] A 3 and A 4 Preferably A 3 and A 4 At least one of them is a divalent aromatic ring group, more preferably A. 3 and A 4 At least one of them is phenylene, and more preferably A. 3 and A 4 It is a phenylene oxide, and A is particularly preferred. 3 and A 4 It is 1,4-phenylene.

[0083] Specific examples of a particular diamine (B) include, for example, aliphatic diamines such as m-phenylenediamine, pentamethyldiamine, hexamethylenediamine, and compounds represented by the following formulas (B-1) to (B-5);

[0084] Examples of alicyclic diamines include 4,4'-ethylenebis(cyclohexylamine);

[0085] Examples of aromatic diamines include 4,4'-diaminodiphenylethane, 4,4'-diaminodiphenylpropane, 4,4'-diaminodiphenylhexane, 4,4'-diaminodiphenyloctane, 4,4'-diaminodiphenyldecane, 1,3-bis(4-aminophenethyl)urea, 1,3-bis(4-aminobenzyl)urea, 1,2-bis(4-aminophenoxy)ethane, and 1,3-bis(4-aminophenoxy)propane. 1,4-bis(4-aminophenoxy)butane, 1,5-bis(4-aminophenoxy)pentane, 1,6-bis(4-aminophenoxy)hexane, bis[2-(4-aminophenyl)ethyl]adipic acid, 4,4'-[4,4'-propane-1,3-diylbis(piperidine-1,4-diyl)]diphenylamine, diethylene glycol bis(4-aminophenyl) ether, and compounds represented by formulas (B-6) to (B-15) below, etc.

[0086] Examples of diamino organosiloxanes include 1,3-bis(3-aminopropyl)-tetramethyldisiloxane. Furthermore, "Boc" in the structural formula represents a tert-butoxycarbonyl group (the same applies below).

[0087] [Chemistry 7]

[0088]

[0089] [Chemistry 8]

[0090]

[0091] As a specific diamine (B), from the viewpoint of improving liquid crystal orientation, an aromatic diamine is preferred, and more preferably, at least one selected from the group consisting of 4,4'-diaminodiphenylethane, 4,4'-diaminodiphenylpropane, 4,4'-diaminodiphenylhexane, 4,4'-diaminodiphenyloctane, 4,4'-diaminodiphenyldecane, 1,3-bis(4-aminophenoxy)urea, 1,3-bis(4-aminobenzyl)urea, 1,2-bis(4-aminophenoxy)ethane, 1,3-bis(4-aminophenoxy)propane, 1,4-bis(4-aminophenoxy)butane, 1,5-bis(4-aminophenoxy)pentane, 1,6-bis(4-aminophenoxy)hexane, bis[2-(4-aminophenyl)ethyl]adipic acid, and compounds represented by formulas (B-6), (B-8), and (B-15), respectively.

[0092] • Structural unit (U3)

[0093] The structural unit (U3) is a structural unit derived from a diamine (hereinafter also referred to as "specific diamine (C)") having a partial structure represented by the following formula (2).

[0094] [Chemistry 9]

[0095]

[0096] (In formula (2), X) 1 It is a monovalent thermally degraded radical; d is 1 or 2; when d is 1, R 4 For "-C(R) 7 (R) 8 )-” or ">C=NR 20 "When d is 2, R 4 for" "(in," "Indicates a bond with a nitrogen atom); R 20 It is a hydrogen atom or a monovalent organic group; R 5 For "-C(R) 7 (R) 8 )-”, or a substituted or unsubstituted divalent alicyclic group; R 7 and R 8 Each can be an independent hydrogen atom or a substituent; R 6 It is a hydrogen atom, or a substituted or unsubstituted monovalent aliphatic hydrocarbon group; a is 1 or 2; b is 0 or 1; c is 0 or 1; where a + b + c = 2; in R 7 In the case of two Rs, 7 Same or different; in R 8 In the case of two Rs,8 Same or different; "Indicates a bond".

[0097] In the above equation (2), X is... 1 The monovalent thermally degradable radical represented can be applied to the R... 1 Explanation of the monovalent thermally detachable radical.

[0098] When d is 1 and R 4 For "-C(R) 7 (R) 8 In the case of )-”, as R 7 and R 8 Examples of substituents include: alkyl groups with 1 to 3 carbon atoms, alkoxy groups with 1 to 3 carbon atoms, halogen atoms, primary amino groups, cyano groups, nitro groups, hydroxyl groups, carboxyl groups, etc. R 7 and R 8 Preferably, it is a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, a halogen atom, or a hydroxyl group, more preferably a hydrogen atom. Additionally, when d is 1 and R... 4 For ">C=NR 20 In the case of ", as R 20 The monovalent organic group represented can be applied to the R... 1 Explanation of the monovalent organic group represented. R 20 Preferably, it contains hydrogen atoms, alkyl groups having 1 to 3 carbon atoms, or Boc groups.

[0099] When d is 2 and R 4 for" In the case of ", as R 7 The substituents represented can be applied to the R... 7 and R 8 Explanation of the substituents indicated.

[0100] As R 5 For "-C(R) 7 (R) 8 R when )-” 7 and R 8 The R can be applied 4 For "-C(R) 7 (R) 8 R when )-” 7 and R 8 Explanation.

[0101] As R 5 The divalent alicyclic group represented can be exemplified by removing any two hydrogen atoms bonded to the carbon atoms constituting the aliphatic ring. The aliphatic ring can be a saturated or unsaturated hydrocarbon ring having 3 to 10 carbon atoms. Preferably, it is a group formed by removing any two hydrogen atoms from a cyclopentane or cyclohexane ring.

[0102] As R 5 The substituents represented by the divalent alicyclic group when they have substituents can be applied to the R. 7 and R 8 Explanation of the substituents indicated.

[0103] R 5 Preferably, it is "-C(R) 7 (R) 8 )-" or 1,4-cyclohexanediyl, more preferably "-C(R 7 (R) 8 )-".

[0104] As R 6 The monovalent aliphatic hydrocarbon group represented can be listed as a chain hydrocarbon group with 1 to 6 carbon atoms or an alicyclic hydrocarbon group with 3 to 6 carbon atoms.

[0105] As R 6 The substituents represented by the monovalent aliphatic hydrocarbon group when it has substituents can be applied to the R... 7 and R 8 Explanation of the substituents indicated.

[0106] R 6 Preferably, it is a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or a cyclohexyl group; more preferably, it is a hydrogen atom or a methyl group; and even more preferably, it is a hydrogen atom.

[0107] The polymer (P) may have at least a portion of the partial structure represented by formula (2) in the main chain of the polymer, and may also have the partial structure represented by formula (2) in the side chains. Additionally, in the polymer (P), X in formula (2) 1 The bonded nitrogen atoms can form part of the polymer backbone or be contained in the side chains. From the viewpoint of improving liquid crystal orientation, the polymer (P) preferably has a partial structure represented by formula (2) in its side chains. Furthermore, from the viewpoint of this, X in formula (2) 1 The bonded nitrogen atom is preferably contained in the side chain of the polymer (P), more preferably contained in the side chain of the polymer (P) and bonded to the carbon atom constituting the main chain of the polymer (P) (i.e., d in the formula (2) is 2, R 4 for" (”).

[0108] The specific diamine (C) can be any diamine having a partial structure represented by formula (2), and may have one or more partial structures represented by formula (2). From the viewpoint of improving film strength and electrical properties while maintaining good liquid crystal alignment, and from the viewpoint of ease of diamine synthesis, one or two are preferred. The specific diamine (C) is preferably an aromatic diamine, and more preferably has a structure that can introduce the partial structure represented by formula (2) into the side chain of the polymer (P). As a preferred example of the specific diamine (C), a compound represented by formula (4) can be listed below. In addition, the specific diamine (C) may also have the partial structure represented by formula (2) and the partial structure Y.

[0109] [Chemistry 10]

[0110]

[0111] (In formula (4), A) 5 and A 6 Each is independently a divalent aromatic cyclic group; Z 1 and Z 2 Each is an independent part of the structure represented by equation (2); R 13 R 14 and R 15 Each is independently a single bond, a divalent chain hydrocarbon group, or any methylene group in a divalent chain hydrocarbon group via -O-, -S-, -CO-, or -NR. 16 -CO- or -NR 16 -CO-NR 17 - A divalent group formed by substitution; R 16 and R 17 Each is independently a hydrogen atom or a monovalent organic group; m is an integer greater than or equal to 0; in Z 2 In the case of multiple Z, multiple Z 2 Same or different; in R 14 In the case of multiple Rs, multiple Rs 14 Same or different).

[0112] In the above equation (4), A 5 and A 6 The divalent aromatic cyclic group represented can be applied to the A... 3 and A 4 Explanation of the divalent aromatic ring group.

[0113] R 13 R 14 and R 15 Preferably, the single bond, divalent chain hydrocarbon group, or any methylene group in the divalent chain hydrocarbon group via -O-, -CO-, or -NR is used. 16The divalent group formed by -CO- substitution is more preferably a divalent group formed by -O- substitution of any methylene group in a single bond, a divalent chain hydrocarbon group, or a divalent chain hydrocarbon group.

[0114] As R 16 and R 17 The monovalent organic group represented can be applied to the R... 1 Explanation of the monovalent organic group represented.

[0115] m is preferably an integer from 0 to 3, more preferably an integer from 0 to 2, and even more preferably 0 or 1.

[0116] Specific examples of a particular diamine (C) include compounds represented by formulas (C-1) to (C-7) below.

[0117] [Chemistry 11]

[0118]

[0119] The polymer (P) can be any polymer containing structural units (U1), (U2), and (U3), and its main framework is not particularly limited. However, in terms of high affinity for liquid crystals, high mechanical strength, and the ability to form a highly reliable liquid crystal alignment film, it is preferably selected from at least one of the group consisting of polyamic acid, polyamic acid ester, and polyimide. Furthermore, when the polymer (P) is selected from at least one of the group consisting of polyamic acid, polyamic acid ester, and polyimide, the choice of monomer is highly flexible, and it is relatively easy to obtain a polymer having the partial structure represented by formula (1) and the partial structure represented by formula (2) and having the partial structure Y in the main chain. From the viewpoint of obtaining better liquid crystal alignment and reliability, it is more preferably selected from at least one of the group consisting of polyamic acid and polyimide, and more preferably polyamic acid.

[0120] [Polyamic acid]

[0121] When the polymer (P) is polyamic acid, a polyamic acid (hereinafter also referred to as "polyamic acid (P)") containing structural units (U1), structural units (U2) and structural units (U3) in the same molecule can be obtained by polymerization using tetracarboxylic dianhydride and a diamine containing a specific diamine (A), a specific diamine (B) and a specific diamine (C).

[0122] (Tetracarboxylic acid dianhydride)

[0123] Examples of tetracarboxylic dianhydrides used in the synthesis of polyamic acid (P) include aliphatic tetracarboxylic dianhydrides and aromatic tetracarboxylic dianhydrides. Examples of aliphatic tetracarboxylic dianhydrides include chain tetracarboxylic dianhydrides and alicyclic tetracarboxylic dianhydrides.

[0124] Specific examples of them include, for instance, 1,2,3,4-butanetetracarboxylic anhydrides, as well as chain-like tetracarboxylic anhydrides.

[0125] Examples of alicyclic tetracarboxylic dianhydrides include 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentylacetic acid dianhydride, 1,3,3a,4,5,9b-hexahydro-5-(tetrahydro-2,5-dioxo-3-furanyl)-naphtho[1,2-c]furan-1,3-dione, and 1,3,3a,4,5,9b-hexahydro-8-methyl-5-(tetrahydro-2,5-dioxo-3-furanyl)-naphtho[1,2-c]furan-1,3-dione. c] Furan-1,3-dione, 3-oxabicyclo[3.2.1]octane-2,4-dione-6-spirocyclic-3'-(tetrahydrofuran-2',5'-dione), 5-(2,5-dioxotetrahydro-3-furanyl)-3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride, 3,5,6-tricarboxy-2-carboxymethylnorbornene-2:3,5:6-dianhydride, 2,4,6,8-tetracarboxybicyclo[3.3.0]octane-2:4,6:8-dianhydride, 4,9-dioxatricyclo[5.3.1.0] 2,6 Undecane-3,5,8,10-tetraone, cyclohexanetetracarboxylic dianhydride, etc.;

[0126] Examples of aromatic tetracarboxylic dianhydrides include pyromellitic dianhydride, 4,4'-(hexafluoroisopropylidene)diphthalic anhydride, ethylene glycol dipreptyltrihydride, 4,4'-carbonyldiphthalic anhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, and 3,3',4,4'-diphenyl ether tetracarboxylic dianhydride; in addition, the tetracarboxylic dianhydrides described in Japanese Patent Application Publication No. 2010-97188 can also be cited.

[0127] From the perspective of improving the solubility of polymers and obtaining liquid crystal alignment films exhibiting good electrical properties, alicyclic tetracarboxylic dianhydrides are preferred as tetracarboxylic dianhydrides. Furthermore, alicyclic tetracarboxylic dianhydrides are preferably selected from 2,3,5-tricarboxycyclopentylacetic acid dianhydride, 1,3,3a,4,5,9b-hexahydro-5-(tetrahydro-2,5-dioxo-3-furanyl)-naphtho[1,2-c]furan-1,3-dione, 1,3,3a,4,5,9b-hexahydro-8-methyl-5-(tetrahydro-2,5-dioxo-3-furanyl)-naphtho[1,2-c]furan-1,3-dione, and bicyclo[3.3.0]octane-2,4,6,8-tetracarboxylic acid dianhydride. The acid is at least one selected from the group consisting of 2,4,6,8-dianhydride, 1,2,3,4-cyclobutanetetracarboxylic acid dianhydride and 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic acid dianhydride, particularly preferably at least one selected from the group consisting of 2,3,5-tricarboxycyclopentylacetic acid dianhydride, bicyclo[3.3.0]octane-2,4,6,8-tetracarboxylic acid 2:4,6:8-dianhydride, 1,2,3,4-cyclobutanetetracarboxylic acid dianhydride and 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic acid dianhydride.

[0128] When alicyclic tetracarboxylic dianhydride is included as the tetracarboxylic dianhydride, the content of alicyclic tetracarboxylic dianhydride is preferably 10 mol% or more, more preferably 20 mol% to 100 mol%, relative to the total amount of tetracarboxylic dianhydride used in the synthesis of polyamic acid.

[0129] (Diamine)

[0130] The diamines used in the synthesis of polyamic acid (P) can be specific diamines (A), (B), and (C), but different diamines (hereinafter also referred to as "other diamines") can also be used. Examples of other diamines include aliphatic diamines, aromatic diamines, and diamino organosiloxanes. Aliphatic diamines include chain diamines and alicyclic diamines.

[0131] Specific examples of other diamines, such as chain diamines, include m-phenylenediamine, 1,3-bis(aminomethyl)cyclohexane, etc.

[0132] Examples of alicyclic diamines include 1,4-diaminocyclohexane and 4,4'-methylenebis(cyclohexylamine);

[0133] Examples of aromatic diamines include p-phenylenediamine, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl sulfide, 1,5-diaminonaphthalene, 2,2'-dimethyl-4,4'-diaminobiphenyl, 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl, 4,4'-diaminodiphenyl ether, 9,9-bis(4-aminophenyl)fluorene, 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane, 4,4'-(p-phenylene diisopropylidene)bisaniline, 1,4-bis(4-aminophenoxy)benzene, 2,6-diaminopyridine, 1,4-bis(4-aminophenyl)piperazine, 1-(4-aminophenyl)-2,3-dihydro-1,3,3-trimethyl-1H-inden-5-amine, and 1-(4-aminophenyl)-2,3-diphenyldiphenylamine. Hydrogen-1,3,3-trimethyl-1H-inden-6-amine, 3,5-diaminobenzoic acid, cholesteryloxy-3,5-diaminobenzene, cholesteryloxy-3,5-diaminobenzene, cholesteryloxy-2,4-diaminobenzene, cholesteryl ester of 3,5-diaminobenzoic acid, cholesteryl ester of 3,5-diaminobenzoic acid, lanosteryl ester of 3,5-diaminobenzoic acid, 3,6-bis(4-aminobenzoyloxy)cholestane, 4-(4'-trifluoromethoxybenzoyloxy)cyclohexyl-3,5-diaminobenzoic acid ester, 1,1-bis(4-((aminophenyl)methyl)phenyl)-4-heptylcyclohexane, 2,4-diamino-N,N-diallylaniline, 4-aminobenzylamine, diamines containing cinnamic acid structures, and compounds represented by the following formula (E-1), etc.

[0134] [Chemistry 12]

[0135]

[0136] (In formula (E-1), X) I and X II Each is independently a single bond, -O-, -COO- or -OCO- (where, " "" indicates a bond with the diaminophenyl side); R I It is an alkyldiyl group with 1 to 3 carbon atoms; R II It is a single bond or an alkyl diel with 1 to 3 carbon atoms; R III It is an alkyl, alkoxy, fluoroalkyl, or fluoroalkoxy group having 1 to 20 carbon atoms; a is 0 or 1; b is an integer from 0 to 3; c is an integer from 0 to 2; d is 0 or 1; where 1 ≦ a + b + c ≦ 3).

[0137] Examples of diamino organosiloxanes include 1,3-diaminomethyltetramethyldisiloxane, and the diamine described in Japanese Patent Application Publication No. 2010-97188 may also be used.

[0138] As in the above formula (E-1) "-X" I -(R I -X II ) d The divalent group represented by "-" is preferably an alkyldiyl group having 1 to 3 carbon atoms. -O-、 -COO- or -O-C2H4-O- (wherein, the one with " The bond between R and diaminophenyl is bonded. III The represented group is preferably linear. The two amino groups in the diaminophenyl group are preferably located at the 2,4- or 3,5-position relative to the other groups.

[0139] As specific examples of compounds represented by formula (E-1), compounds represented by formulas (E-1-1) to (E-1-4) can be listed below.

[0140] [Chemistry 13]

[0141]

[0142] In the synthesis of polyamic acid (P), from the viewpoint of achieving a high effect in mitigating accumulated charge and improving electrical properties, the proportion of a specific diamine (A) used relative to the total amount of diamines used in the synthesis of polyamic acid (P) is preferably 3 mol% or more, more preferably 5 mol% or more, further preferably 10 mol% or more, and particularly preferably 15 mol% or more. Furthermore, relative to the total amount of diamines used in the synthesis of polyamic acid (P), the proportion of a specific diamine (A) used is preferably 70 mol% or less, more preferably 60 mol% or less, further preferably 50 mol% or less, and particularly preferably 40 mol% or less.

[0143] From the viewpoint of achieving improved film strength while exhibiting good liquid crystal alignment, the proportion of a specific diamine (B) used is preferably 5 mol% or more, more preferably 10 mol% or more, further preferably 15 mol% or more, and particularly preferably 20 mol% or more, relative to the total amount of diamines used in the synthesis of polyamic acid (P). Furthermore, the proportion of a specific diamine (B) used is preferably 80 mol% or less, more preferably 70 mol% or less, further preferably 60 mol% or less, and particularly preferably 50 mol% or less, relative to the total amount of diamines used in the synthesis of polyamic acid (P).

[0144] From the viewpoint of achieving improved electrical properties and film strength while exhibiting good liquid crystal alignment, the proportion of a specific diamine (C) used is preferably 10 mol% or more, more preferably 15 mol% or more, further preferably 20 mol% or more, and particularly preferably 25 mol% or more, relative to the total amount of diamines used in the synthesis of polyamic acid (P). Furthermore, the proportion of a specific diamine (C) used is preferably 80 mol% or less, more preferably 70 mol% or less, further preferably 60 mol% or less, and particularly preferably 50 mol% or less, relative to the total amount of diamines used in the synthesis of polyamic acid (P).

[0145] (Synthesis of polyamic acid)

[0146] Polyamic acid (P) can be obtained by reacting a tetracarboxylic dianhydride as described above with a diamine and a molecular weight adjuster as desired. The preferred ratio of tetracarboxylic dianhydride to diamine used in the synthesis reaction of polyamic acid (P) is 0.2 to 2 equivalents relative to the amino group of the diamine and the anhydride group of the tetracarboxylic dianhydride, more preferably 0.3 to 1.2 equivalents relative to the amino group of the diamine.

[0147] Examples of molecular weight modifiers include: 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 proportion of the molecular weight modifier used is preferably 20 parts by mass or less, and more preferably 10 parts by mass or less, relative to a total of 100 parts by mass of the tetracarboxylic dianhydride and diamine used.

[0148] The synthesis reaction of polyamic acid is preferably carried out in an organic solvent. The reaction temperature is preferably -20°C to 150°C, more preferably 0°C to 100°C. Furthermore, the reaction time is preferably 0.1 hours to 24 hours, more preferably 0.5 hours to 12 hours.

[0149] Examples of organic solvents used in the reaction include: aprotic polar solvents, phenolic solvents, alcohols, ketones, esters, ethers, halogenated hydrocarbons, and hydrocarbons. Among these organic solvents, it is preferable to use one or more from the group consisting of aprotic polar solvents and phenolic solvents (organic solvents of the first group), or a mixture of one or more organic solvents selected from the first group and one or more from the group consisting of alcohols, ketones, esters, ethers, halogenated hydrocarbons, and hydrocarbons (organic solvents of the second group). In the latter case, the proportion of organic solvents from the second group used is preferably 50% by mass or less, more preferably 40% by mass or less, and even more preferably 30% by mass or less, relative to the total amount of organic solvents from the first group and the second group.

[0150] Particularly preferred organic solvents are those selected from the group consisting of N-methyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide, dimethyl sulfoxide, γ-butyrolactone, tetramethylurea, hexamethylphosphoric triamine, m-cresol, xylenol, and halogenated phenols, or mixtures of one or more of these solvents with other organic solvents within the stated proportions. The amount (x) of organic solvent used is preferably set such that the total amount (y) of tetracarboxylic dianhydride and diamine is 0.1% to 50% by mass relative to the total amount (x+y) of the reaction solution.

[0151] The reaction solution obtained by dissolving polyamic acid is as described above. This reaction solution can be used directly for the preparation of a liquid crystal alignment agent, or it can be used after separating the polyamic acid contained in the reaction solution, or it can be used after purifying the separated polyamic acid. In the case of producing polyimide by dehydrating and ring-closing polyamic acid, the reaction solution can be used directly for the dehydration and ring-closing reaction, or it can be used after separating the polyamic acid contained in the reaction solution, or it can be used after purifying the separated polyamic acid. The separation and purification of polyamic acid can be carried out according to known methods.

[0152] [Polyamide ester]

[0153] Polyamates as polymers (P) can be obtained, for example, by methods such as: [I] reacting polyamic acid (P) obtained through the aforementioned synthesis reaction with an esterifying agent; [II] reacting a tetracarboxylic acid diester with a diamine; [III] reacting a tetracarboxylic acid diester dihalide with a diamine. The polyamates contained in the liquid crystal alignment agent may have only an amide ester structure, or may be a partial esterification containing both an amide acid structure and an amide ester structure. Furthermore, the reaction solution obtained by dissolving the polyamate can be directly used in the preparation of the liquid crystal alignment agent, or it can be used in the preparation of the liquid crystal alignment agent after separating the polyamate contained in the reaction solution, or it can be used in the preparation of the liquid crystal alignment agent after purifying the separated polyamate. The separation and purification of the polyamate can be carried out according to known methods.

[0154] [Polyimide]

[0155] Polyimides as polymers (P) can be obtained, for example, by dehydrating and cyclizing polyamic acid (P) synthesized as described above and then imidizing it.

[0156] The polyimide can be a fully imidized product obtained by dehydrating and ring-closing all of the amic acid structure of polyamic acid (P) as its precursor, or a partially imidized product obtained by dehydrating and ring-closing only a portion of the amic acid structure, resulting in the coexistence of the amic acid structure and the imide ring structure. The polyimide contained in the liquid crystal alignment agent of this disclosure preferably has an imidization rate of 20% or more, more preferably 30% to 90%, and even more preferably 40% to 80%. The imidization rate is particularly preferably 60% or less. The imidization rate is expressed as a percentage, representing the proportion of the number of imide ring structures relative to the total number of amic acid structures and the number of imide ring structures in the polyimide. Here, a portion of the imide ring may be an isoimide ring.

[0157] The dehydration and ring-closing of polyamic acid (P) is preferably carried out by heating the polyamic acid (P) or by dissolving the polyamic acid in an organic solvent and adding a dehydrating agent and a dehydration and ring-closing catalyst to the solution as needed and then heating it.

[0158] In the method of adding a dehydrating agent and a dehydration ring-closing catalyst to a solution of polyamic acid (P), the dehydrating agent can be, for example, anhydrides such as acetic anhydride, propionic anhydride, and trifluoroacetic anhydride. The amount of dehydrating agent used is preferably 0.01 mol to 20 mol relative to 1 mol of the amic acid structure of polyamic acid (P). The dehydration ring-closing catalyst can be, for example, a tertiary amine such as pyridine, trimethylpyridine, dimethylpyridine, triethylamine, or 1-methylpiperidine. The amount of dehydration ring-closing catalyst used is preferably 0.01 mol to 10 mol relative to 1 mol of the dehydrating agent used. Examples of organic solvents used in the dehydration ring-closing reaction include those used in the synthesis of polyamic acid (P). The reaction temperature of the dehydration ring-closing reaction is preferably 0°C to 180°C, more preferably 10°C to 150°C. The reaction time is preferably 1.0 h to 120 h, more preferably 2.0 h to 30 h.

[0159] A reaction solution containing polyimide is obtained as described. This reaction solution can be used directly for the preparation of a liquid crystal alignment agent, or it can be used for the preparation of a liquid crystal alignment agent after removing the dehydrating agent and dehydration ring-closing catalyst from the reaction solution, or it can be used for the preparation of a liquid crystal alignment agent after separating the polyimide, or it can be used for the preparation of a liquid crystal alignment agent after purifying the separated polyimide. These purification operations can be carried out according to known methods. Furthermore, polyimide can also be obtained by imidization of polyaminates.

[0160] The polyamic acid, polyamic ester, and polyimide obtained as polymers (P) in the above manner preferably have a solution viscosity of 20 mPa·s to 1,800 mPa·s when prepared as a 15% by mass solution, more preferably a solution viscosity of 50 mPa·s to 1,500 mPa·s. Furthermore, the solution viscosity (mPa·s) of the polyamic acid, polyamic ester, and polyimide is a value obtained by measuring a 15% by mass polymer solution prepared using a good solvent (e.g., γ-butyrolactone, N-methyl-2-pyrrolidone, etc.) at 25°C using an E-type rotational viscometer.

[0161] The weight-average molecular weight (Mw) of polyamic acid, polyamic acid ester, and polyimide (P) converted from polystyrene by gel permeation chromatography (GPC) is preferably 1,000 to 500,000, more preferably 2,000 to 300,000. Furthermore, the molecular weight distribution (Mw / Mn) expressed as the ratio of Mw to the number-average molecular weight (Mn) of polystyrene determined by GPC is preferably 8 or less, more preferably 6 or less. By ensuring that Mw and Mw / Mn are within these ranges, good liquid crystal alignment of the liquid crystal element can be ensured.

[0162] The proportion of polyamic acid, polyamic acid ester and polyimide as polymers (P) in the liquid crystal alignment agent disclosed herein is preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 70% by mass or more, relative to the total amount of solid components (components other than the solvent component of the liquid crystal alignment agent) contained in the liquid crystal alignment agent.

[0163] <Other Ingredients>

[0164] In addition to the polymer (P), the liquid crystal alignment agent disclosed herein may contain other components as needed. Examples of other components include polymers different from polymer (P) (hereinafter also referred to as "other polymers"), solvents, crosslinking agents, antioxidants, metal chelating compounds, curing accelerators, surfactants, fillers, dispersants, photosensitizers, etc. The proportions of these other components can be appropriately selected based on the suitability of each compound without impairing the effects of the invention.

[0165] [Other polymers]

[0166] Other polymers are acceptable as long as they do not contain structural units (U1), (U2), and (U3), and their main framework is not particularly limited. As for other polymers, from the viewpoint of high affinity for liquid crystals and improved reliability of liquid crystal elements when used with said polymer (P), at least one polymer selected from the group consisting of polyamic acid, polyamic acid ester, and polyimide (hereinafter also referred to as "polymer (Q)") is preferred. From the viewpoint of better liquid crystal orientation and reliability, at least one polymer selected from the group consisting of polyamic acid and polyimide is more preferred, and polyamic acid is more preferred. The descriptions of the polyamic acid, polyamic acid ester, and polyimide as polymer (Q) are applicable beyond those related to the specific diamines (A), (B), and (C) in said polymer (P).

[0167] From the viewpoint of obtaining a liquid crystal alignment film exhibiting excellent liquid crystal alignment properties when photoalignment is applied, the polymer (Q) preferably contains structural units derived from tetracarboxylic dianhydride (hereinafter also referred to as "cyclobutanetetracarboxylic dianhydride") having a cyclobutane ring structure. Specific examples of cyclobutanetetracarboxylic dianhydride include, for example, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, methyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, and 1,2,3,4-tetramethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride. Among these, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride is preferred in terms of further improving the photoreactivity of the coating film formed using the liquid crystal alignment agent.

[0168] When the polymer (Q) contains structural units derived from cyclobutanetetracarboxylic dianhydride, the proportion of the tetracarboxylic dianhydride used in the synthesis of the polymer (Q) is preferably 70 mol% or more, more preferably 80 mol% or more, and even more preferably 90 mol% or more.

[0169] When the liquid crystal alignment agent contains polymer (Q), the content of polymer (Q) is preferably 10% by mass or more, more preferably 20% by mass or more, and even more preferably 30% by mass or more, relative to the total amount of polymer (P) and polymer (Q). Furthermore, the content of polymer (Q) is preferably 80% by mass or less, more preferably 70% by mass or less, and even more preferably 60% by mass or less, relative to the total amount of polymer (P) and polymer (Q).

[0170] When imparting liquid crystal alignment capability to a liquid crystal alignment film formed using a liquid crystal alignment agent via photoalignment, it is preferable to have at least a portion of polymers (P) and (Q) as polymers having photoalignable groups. A photoalignable group refers to a functional group capable of imparting anisotropy to the film through photoreactions such as photoisomerization, photodimerization, photoFries rearrangement, or photodecomposition induced by light irradiation.

[0171] Specific examples of photooriented groups include: groups containing azobenzene or its derivatives as the basic framework; groups containing cinnamic acid or its derivatives (cinnamic acid structure) as the basic framework; groups containing chalcone or its derivatives as the basic framework; groups containing benzophenone or its derivatives as the basic framework; groups containing coumarin or its derivatives as the basic framework; groups containing cyclobutane or its derivatives as the basic framework; groups containing stilbene or its derivatives as the basic framework; and groups containing phenyl benzoate or its derivatives as the basic framework. Among these, the photo-orientation group is preferably selected from at least one group consisting of azobenzene-containing groups, cinnamic acid-containing groups, chalcone-containing groups, stilbene-containing groups, cyclobutane-containing groups, and phenyl benzoate-containing groups. In terms of high light sensitivity and ease of introduction into the polymer, groups containing cinnamic acid-containing groups or cyclobutane-containing groups are preferred.

[0172] There are no particular limitations on the synthesis method of polymers with photo-oriented groups. Polymers with photo-oriented groups can be obtained, for example, by: (1) by polymerization of monomers with photo-oriented groups; (2) by synthesizing polymers having a first functional group (e.g., epoxy group) in the side chain, and by reacting the polymer containing the first functional group obtained by said synthesis with a reactive compound having a second functional group (e.g., carboxyl group) and a photo-oriented group that forms a bond with the first functional group.

[0173] [solvent]

[0174] The liquid crystal alignment agent disclosed herein is prepared in the form of a liquid composition, wherein the liquid composition is formed by dispersing or dissolving a polymer (P) and other components, which may be arbitrarily formulated as needed, in a solvent. The solvent is preferably an organic solvent, such as: aprotic polar solvents, phenolic solvents, alcohols, ketones, esters, ethers, halogenated hydrocarbons, hydrocarbons, etc.

[0175] Specific examples of the organic solvents used include: N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolium ketone, γ-butyrolactone, γ-butyrolactam, N,N-dimethylformamide, N,N-dimethylacetamide, 4-hydroxy-4-methyl-2-pentanone (diacetone alcohol), ethylene glycol monomethyl ether, butyl lactate, butyl acetate, methyl methoxypropionate, ethyl ethoxypropionate, ethylene glycol monomethyl ether, etc. Ethyl alcohol ether, ethylene glycol-n-propyl ether, ethylene glycol-isopropyl 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, diisoamyl ether, ethylene carbonate, propylene carbonate, cyclohexanone, 3-methoxy-1-butanol, etc.

[0176] [Cross-linking agent]

[0177] Liquid crystal alignment agents may contain crosslinking agents. Preferably, the following compounds are used as crosslinking agents: having a total of two or more groups selected from oxetyl, oxetyl, cyclic thioether, cyclic carbonate, hydroxyl, protected hydroxyl, hydroxymethyl, protected hydroxymethyl, mercapto, protected mercapto, amino, protected amino, isocyanate, protected isocyanate, polymerizable carbon-carbon unsaturated groups (alkenyl, vinyl ether, vinylphenyl, maleimide, (meth)acryloyl, etc.), β-hydroxyalkylamide, β-alkoxyalkylamide, oxazoline, aldehyde, carbodiimide, protected carboxyl, α-CR 60 =CR 61 -R 62 - (where R) 60 R is a monovalent organic group that is deactivated through a reaction with an amino group. 61 R is a hydrogen atom or an alkyl group; 62 It is at least one crosslinking group from the group consisting of electron-attracting groups, silanol groups, and alkoxysilyl groups. The number of crosslinking groups in the crosslinking agent is preferably two or more, more preferably two to twelve, and even more preferably two to ten.

[0178] Specific examples of crosslinking agents include compounds represented by formulas (c-1) to (c-19) below.

[0179] [Chemistry 14]

[0180]

[0181] [Chemistry 15]

[0182]

[0183] (In formula (c-8), Ac is an acetyl group)

[0184] [Chemistry 16]

[0185]

[0186] (In equations (c-10) and (c-11), R) 93 (tert-butoxy)

[0187] [Chemistry 17]

[0188]

[0189] From the viewpoint of obtaining a liquid crystal alignment film that maintains good liquid crystal alignment while exhibiting excellent adhesion, compounds without aromatic rings (hereinafter also referred to as "aliphatic crosslinking agents") are preferably used as crosslinking agents. Aliphatic crosslinking agents can be compounds containing chain structures or cyclic structures. Specific examples of aliphatic crosslinking agents include compounds without aromatic rings among the illustrated compounds.

[0190] When the crosslinking agent is incorporated into the liquid crystal alignment agent, the content of the crosslinking agent is preferably 20 parts by mass or less, more preferably 10 parts by mass or less, and even more preferably 5 parts by mass or less, and particularly preferably 3 parts by mass or less, relative to the total amount of polymer components.

[0191] The concentration of the solid component of the liquid crystal alignment agent (the ratio of the total mass of the liquid crystal alignment agent components excluding the solvent to the total mass of the liquid crystal alignment agent) is appropriately selected considering factors such as viscosity and volatility, and is preferably in the range of 1% to 10% by mass. If the solid component concentration is 1% by mass or more, the film thickness of the coating can be sufficiently ensured, and a liquid crystal alignment film exhibiting good liquid crystal alignment properties can be easily obtained. On the other hand, if the solid component concentration is 10% by mass or less, the coating thickness can be set to an appropriate level, and a liquid crystal alignment film exhibiting good liquid crystal alignment properties can be easily obtained. In addition, the viscosity of the liquid crystal alignment agent becomes moderate, which tends to result in good coatability.

[0192] Liquid crystal alignment films, their manufacturing methods, and liquid crystal elements

[0193] The liquid crystal alignment film of this disclosure can be formed using a liquid crystal alignment agent prepared as described above. Furthermore, the liquid crystal element of this disclosure includes a liquid crystal alignment film formed using the liquid crystal alignment agent described above. The operating mode of the liquid crystal in the liquid crystal element is not particularly limited, and can be applied to various modes such as TN type, STN type, vertical alignment (VA) type (including vertical alignment-multi-domain vertical alignment (VA-MVA) type, vertical alignment-patterned vertical alignment (VA-PVA) type, in-plane switching (IPS) type, fringe field switching (FFS) type, optically compensated bending (OCB) type, and polymer-stable alignment (PSA) type. The liquid crystal element can be manufactured, for example, using a method including the following steps 1 to 3. In step 1, the substrate used varies depending on the desired operating mode. Process 2 and Process 3 are common in all operating modes.

[0194] <Step 1: Coating Formation>

[0195] First, a liquid crystal alignment agent is coated onto a substrate, preferably by heating the coated surface to form a coating film on the substrate. Examples of substrates that can be used include: float glass, soda glass, etc.; and transparent substrates containing resins such as polyethylene terephthalate, polybutylene terephthalate, polyethersulfone, polycarbonate, and poly(alicyclic olefins). As a transparent conductive film disposed on one side of the substrate, NESA film (a registered trademark of PPG Industries, Inc.) containing tin oxide (SnO2) or indium tin oxide (ITO) film containing indium oxide-tin oxide (In2O3-SnO2) can be used. When manufacturing TN, STN, or VA type liquid crystal elements, two substrates with patterned transparent conductive films are used. On the other hand, when manufacturing IPS or FFS type liquid crystal elements, a substrate with comb-shaped electrodes and a substrate without electrodes facing each other are used. The liquid crystal alignment agent is applied to the substrate, preferably by offset printing, flexographic printing, spin coating, roller coating or inkjet printing on the electrode forming surface.

[0196] After coating the liquid crystal alignment agent, preheating (pre-baking) is preferably performed to prevent sagging of the coated liquid crystal alignment agent. The pre-baking temperature is preferably 30°C to 200°C, and the pre-baking time is preferably 0.25 minutes to 10 minutes. Subsequently, a calcination (post-baking) process is performed to further remove solvents, etc. The calcination temperature (post-baking temperature) at this time is preferably 80°C to 250°C, more preferably 80°C to 200°C. The post-baking time is preferably 5 minutes to 200 minutes. The film thickness thus formed is preferably 0.001 μm to 1 μm.

[0197] <Step 2: Orientation Treatment>

[0198] In manufacturing TN, STN, IPS, or FFS type liquid crystal elements, a process (orientation treatment) is performed to impart liquid crystal alignment capability to the coating film formed in step 1. This imparts the alignment capability of liquid crystal molecules to the coating film, forming a liquid crystal alignment film. As an orientation treatment, the following processes can be used: friction treatment, in which the coating film formed on the substrate is rubbed in a certain direction using a roller wound with a cloth containing fibers such as nylon, rayon, or cotton; or photo-orientation treatment, in which the coating film formed on the substrate is irradiated with light to impart liquid crystal alignment capability to the coating film. On the other hand, in manufacturing vertically aligned (VA) type liquid crystal elements, the coating film formed in step 1 can be used directly as a liquid crystal alignment film, but to further improve the liquid crystal alignment capability, an orientation treatment can also be performed on the coating film. The liquid crystal alignment film preferred for vertically aligned liquid crystal elements is also preferred for PSA type liquid crystal elements.

[0199] In photoalignment processing, light irradiation can be performed by methods such as: irradiating a coating after a post-baking process; irradiating a coating after a pre-baking process and before a post-baking process; or irradiating the coating during heating in at least one of the pre-baking and post-baking processes. As the radiation irradiating the coating, for example, ultraviolet light and visible light containing wavelengths of 150 nm to 800 nm can be used. Ultraviolet light containing wavelengths of 200 nm to 400 nm is preferred. When the radiation is polarized, it can be linearly polarized or partially polarized. When the radiation used is linearly polarized or partially polarized, irradiation can be performed from a direction perpendicular to the substrate surface, from an oblique direction, or a combination of these directions. For unpolarized radiation, the irradiation direction is set to an oblique direction.

[0200] Examples of light sources used include: low-pressure mercury lamps, high-pressure mercury lamps, deuterium lamps, metal halide lamps, argon resonance lamps, xenon lamps, and excimer lasers. The preferred irradiation dose of radiation on the substrate surface is 400 J / m².2 ~50,000 J / m 2 More preferably 1,000 J / m 2 ~20,000 J / m 2 After light irradiation to impart alignment capability, the substrate surface may be cleaned using, for example, water, an organic solvent (e.g., methanol, isopropanol, 1-methoxy-2-propanol acetate, butyl cellosolve, ethyl lactate, etc.), or a mixture thereof, or the substrate may be heated. To further improve liquid crystal alignment (heat-realignment), it is preferable to perform a heating treatment of the substrate as a post-light irradiation treatment, and the temperature for heating the substrate is preferably 120°C to 280°C, more preferably 150°C to 250°C.

[0201] <Step 3: Construction of Liquid Crystal Cells>

[0202] Two substrates with liquid crystal alignment films formed as described above are prepared, and liquid crystal is disposed adjacent to the liquid crystal alignment films between the two substrates to manufacture a liquid crystal cell. Methods for manufacturing the liquid crystal cell include: arranging two substrates facing each other with the liquid crystal alignment films facing each other and a gap between them; bonding the peripheries of the two substrates together using a sealant; injecting liquid crystal into the cell gap surrounded by the substrate surfaces and the sealant and sealing the injection hole; and using a liquid crystal drop fill (ODF) method. For example, epoxy resin containing a hardener and alumina spheres as spacers can be used as a sealant. Nematic liquid crystals and smectic liquid crystals can be used as liquid crystals, with nematic liquid crystals being preferred. In PSA mode, after constructing the liquid crystal cell, the liquid crystal cell is subjected to light irradiation while a voltage is applied between the conductive films of the pair of substrates.

[0203] PSA-type liquid crystal elements can be manufactured by a method including the following steps.

[0204] The process of forming a coating by coating the liquid crystal alignment agent of the present disclosure onto the conductive film of each of a pair of substrates having a conductive film.

[0205] The process of constructing a liquid crystal cell by arranging a pair of substrates coated with a liquid crystal alignment agent facing each other with the liquid crystal layer sandwiched between them.

[0206] The process of irradiating a liquid crystal cell with light while applying a voltage between conductive films.

[0207] Specifically, firstly, liquid crystal and photopolymerizable monomer are injected or dropped together between a pair of substrates having a conductive film, and liquid crystal cells are constructed in the same manner as in steps 1 to 3, except as described above. As the photopolymerizable monomer injected or dropped together with the liquid crystal, existing known compounds can be used. A polyfunctional (meth)acrylic acid monomer is preferred.

[0208] In the manufacture of PSA-type liquid crystal elements, 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 a pair of substrates. The applied voltage can be, for example, DC or AC of 5 V to 50 V. The irradiated light can be, for example, ultraviolet light or visible light with wavelengths ranging from 150 nm to 800 nm. Ultraviolet light with wavelengths ranging from 300 nm to 400 nm is preferred. The light source can be, for example, a low-pressure mercury lamp, a high-pressure mercury lamp, a deuterium lamp, a metal halide lamp, an argon resonance lamp, a xenon lamp, or an excimer laser. The preferred light intensity is 1,000 J / m². 2 ~200,000 J / m 2 More preferably 1,000 J / m 2 ~100,000 J / m 2 .

[0209] For each type of liquid crystal cell, a polarizing plate is then attached to the outer surface of the liquid crystal cell as needed to form a liquid crystal element. Examples of polarizing plates include: polarizing plates made by sandwiching a polarizing film called an "H film" formed by a cellulose acetate protective film that allows polyvinyl alcohol to absorb iodine while being extended and oriented; or polarizing plates that include the H film itself.

[0210] The liquid crystal element disclosed herein can be effectively applied to a variety of uses. Specifically, it can be used, for example, as a display device or dimming device, or retardation film, in various applications such as clocks, portable game consoles, word processors, notebook computers, car navigation systems, camcorders, personal digital assistants (PDAs), digital cameras, mobile phones, smartphones, various monitors, LCD TVs, information displays, and other display devices.

[0211] According to this disclosure, the following means may be provided.

[0212] [Method 1] A liquid crystal alignment agent comprising a polymer (P) containing the structural unit (U1), the structural unit (U2) and the structural unit (U3) within the same molecule.

[0213] [Method 2] According to [Method 1], the liquid crystal alignment agent, wherein the polymer (P) is at least one selected from the group consisting of polyamic acid, polyamic acid ester and polyimide.

[0214] [Method 3] The liquid crystal alignment agent according to [Method 1] or [Method 2], wherein the polymer (P) has a partial structure represented by the formula (1) in the main chain.

[0215] [Method 4] The liquid crystal alignment agent according to any one of [Method 1] to [Method 3], wherein B in formula (1) 1 For -NR 1 -

[0216] [Method 5] A liquid crystal alignment agent according to any one of [Method 1] to [Method 4], wherein the polymer (P) contains nitrogen atoms of formula (2) in its side chain.

[0217] [Method 6] The liquid crystal alignment agent according to any one of [Method 1] to [Method 5] further comprises a polymer (Q), said polymer (Q) being at least one selected from the group consisting of polyamic acid, polyamic acid ester and polyimide and different from polymer (P).

[0218] [Method 7] A liquid crystal alignment agent according to any one of [Method 1] to [Method 6], wherein the polymer (Q) comprises a structural unit derived from a tetracarboxylic acid dianhydride having a cyclobutane ring structure.

[0219] [Method 8] The liquid crystal alignment agent according to any one of [Method 1] to [Method 7] contains a crosslinking agent.

[0220] [Method 9] A liquid crystal alignment film is formed using a liquid crystal alignment agent according to any one of [Method 1] to [Method 8].

[0221] [Method 10] A liquid crystal element comprising a liquid crystal alignment film according to [Method 9].

[0222] [Example]

[0223] The present invention will be described in more detail below by way of examples, but the invention is not to be interpreted as limited by the following examples. In the following examples, the necessary amounts of the starting compound and polymer are ensured by repeatedly performing the synthesis at the synthetic scale shown in the following synthetic examples as needed. In addition, unless otherwise specified, "parts" and "%" in the examples and comparative examples are based on mass.

[0224] In the following example, the imidization rate of polyimide in a polymer solution is determined by the following method.

[0225] <Imidification rate of polyimide>

[0226] The polyimide solution was added to pure water, and the resulting precipitate was dried under reduced pressure at room temperature. It was then dissolved in deuterated dimethyl sulfoxide, and proton NMR spectroscopy was performed at room temperature using tetramethylsilane as a reference. 1 H-Nuclear Magnetic Resonance, 1 H-NMR) determination. Based on the obtained 1 The H-NMR spectrum was used to determine the imidization rate [%] using the following formula (1).

[0227] Imidification rate [%] = (1 - (A) 1 / (A 2 ×α)))×100…(1)

[0228] (In equation (1), A 1 The peak area of ​​protons originating from NH groups appearing near a chemical shift of 10 ppm; A 2 The peak area originating from other protons; α is the proportion of other protons in the polymer precursor (polyamic acid) relative to one proton of the NH group.

[0229] The abbreviations for compounds are as follows. Furthermore, the compounds represented by formula (X) are sometimes simply referred to as "compound (X)".

[0230] <Tetracarboxylic dianhydride>

[0231] [Chemistry 18]

[0232]

[0233] <Diamine>

[0234] [Chemistry 19]

[0235]

[0236] [Chemistry 20]

[0237]

[0238] [Chemistry 21]

[0239]

[0240] [Chemistry 22]

[0241]

[0242] [Chemistry 23]

[0243]

[0244] <Additives>

[0245] [Chemistry 24]

[0246]

[0247] <Polymer Synthesis>

[0248] 1. Synthesis of polyamic acid

[0249] [Synthesis example 1]

[0250] 100 moles of compound (CA-1) as a tetracarboxylic acid dianhydride, 30 moles of compound (DB-16) as a diamine, 40 moles of compound (DE-2) and 30 moles of compound (DB-11) were dissolved in N-methyl-2-pyrrolidone (NMP) and reacted at 60°C for 5 hours to obtain a solution containing 15% by mass of polyamic acid (designated as polymer (P1)).

[0251] [Synthesis Examples 2-4, 7-36, and 38]

[0252] Except for changing the type and amount of tetracarboxylic dianhydride and diamine used as described in Table 1, the same operation as in Synthesis Example 1 was performed to obtain polyamic acids (which were designated as polymers (P2) to (P4), polymers (P7) to (P36) and polymer (P38)).

[0253] 2. Synthesis of polyimide

[0254] [Synthesis example 5]

[0255] 100 moles of compound (CA-1) as a tetracarboxylic dianhydride, 30 moles of compound (DB-16) as a diamine, 40 moles of compound (DE-2) and 30 moles of compound (DB-11) were dissolved in NMP and reacted at 40°C for 24 hours to obtain a solution containing 20% ​​by mass of polyamic acid.

[0256] Subsequently, NMP was added to the obtained polyamic acid solution, along with pyridine and acetic anhydride, each in 0.9 molar equivalents relative to the carboxyl groups of the polyamic acid. The mixture was then subjected to a dehydration and ring-closure reaction at 60°C for 4 hours. After the dehydration and ring-closure reaction, the solvent in the system was replaced with fresh NMP, followed by concentration, thereby obtaining a solution containing 20% ​​by mass of polyimide with an imidization rate of approximately 60% (designated as polymer (P5)).

[0257] [Synthesis Example 6 and Synthesis Example 37]

[0258] Except for changing the type and amount of tetracarboxylic dianhydride and diamine used as described in Table 1, the same operation as in Synthesis Example 5 was performed to obtain polyimides (which were designated as polymer (P6) and polymer (P37)).

[0259] Furthermore, in Table 1, the values ​​for tetracarboxylic dianhydrides (dianhydrides 1 to dianhydrides 3) represent the proportion (molar ratio) of each compound relative to 100 molar parts of the total amount of tetracarboxylic dianhydrides used in the synthesis of each polyamic acid. The values ​​for diamines (diamine 1 to diamine 4) represent the proportion (molar ratio) of each compound relative to 100 molar parts of the total amount of diamines used in the synthesis of each polyamic acid.

[0260] [Table 1]

[0261]

[0262] <Preparation and Evaluation of Liquid Crystal Alignment Agents>

[0263] [Example 1: Optical FFS type liquid crystal display element]

[0264] 1. Preparation of liquid crystal alignment agent

[0265] A solution containing 40 parts by mass of polymer (P1) obtained in Synthesis Example 1 and a solution containing 60 parts by mass of polymer (P7) obtained in Synthesis Example 7 were mixed, and NMP and butyl cellosolve (BC) were added to prepare a solution with a solvent composition of NMP / BC = 65 / 35 (mass ratio) and a solid content concentration of 3.5% by mass. The solution was filtered using a filter with a pore size of 0.2 μm to prepare a liquid crystal alignment agent.

[0266] 2. Manufacturing of FFS-type liquid crystal cells using photo-alignment method

[0267] A glass substrate (designated as the first substrate) with a flat plate electrode (bottom electrode), an insulating layer, and a comb-shaped electrode (top electrode) stacked sequentially on one side, and a glass substrate without electrodes (designated as the second substrate) are prepared. Then, the liquid crystal alignment agent prepared in step 1 is applied to the electrode forming surface of the first substrate and one substrate surface of the second substrate using a spinner, and heated at 80°C for 1 minute (pre-baking). Subsequently, it is dried for 30 minutes in a 230°C oven purged with nitrogen (post-baking) to form a coating with an average thickness of 0.1 μm. The obtained coating is then irradiated with 1,000 J / m² ultraviolet light containing a linearly polarized 254 nm bright line from the substrate normal direction using an Hg-Xe lamp. 2A photoalignment process is then performed. Furthermore, the irradiation amount is a value measured using a photometer with a wavelength of 254 nm as the reference. Subsequently, the photoaligned coating is heat-treated by heating it in a clean oven at 230°C for 30 minutes to form a liquid crystal alignment film.

[0268] Next, for one of the pair of substrates with the liquid crystal alignment film, an epoxy resin adhesive containing 3.5 μm diameter alumina spheres was screen-printed onto the outer edge of the surface with the liquid crystal alignment film. Then, the substrates were overlapped and pressed together with the projection direction of the polarization axis on the substrate surface being antiparallel during light irradiation, and the adhesive was thermosetting at 150°C for 1 hour. Subsequently, negative liquid crystal (Merck, MLC-6608) was filled between the pair of substrates through the liquid crystal injection port, and the liquid crystal injection port was sealed using an epoxy adhesive to obtain a liquid crystal cell. Furthermore, to remove the flow alignment during liquid crystal injection, it was heated at 120°C and then slowly cooled to room temperature. Additionally, the post-baked ultraviolet irradiation dose was 100 J / m 2 ~10,000 J / m 2 The series of operations are performed by varying the range of UV exposure to produce three or more liquid crystal cells with different UV exposures. The liquid crystal cell with the best exposure (optimal exposure) is used in the following evaluation of delay rate, orientation uniformity and DC mitigation characteristics.

[0269] 3. Evaluation

[0270] (1) Evaluation of liquid crystal orientation based on retardation rate

[0271] The liquid crystal cell manufactured in step 2. was subjected to a temperature of 27,000 cd / m². 2 The liquid crystal cells were left to stand on a high-brightness backlight for 500 hours, and the liquid crystal alignment was evaluated based on the rate of change in retardation before and after backlight illumination. First, for the liquid crystal cells manufactured in section 2, the retardation was measured using an Axoscan (manufactured by Opto Science), and the rate of change in retardation α before and after backlight illumination was calculated using the following formula (z-1). It can be said that the smaller the rate of change α, the more stable the liquid crystal alignment and the better the reliability. Cases with a rate of change α of less than 1% were designated as "Good (◎)", cases greater than 1% but less than 2% were designated as "Acceptable (○)", and cases greater than 2% were designated as "Poor (×)".

[0272]

[0273] (in equation (z-1), This represents the time difference before and after irradiation. (Indicates the delay value before irradiation)

[0274] As a result, the liquid crystal orientation (orientation stability) of the embodiment was rated as "good (○)".

[0275] (2) Evaluation of orientation uniformity

[0276] Using the liquid crystal cell manufactured in section 2, the delay was measured at any 20 points within a pixel plane using an Axoscan sensor manufactured by Opto Science, and its standard deviation was calculated. Regarding the evaluation, a standard deviation of 0.05 or less was designated as "Good (◎)", a standard deviation greater than 0.05 but less than 0.07 was designated as "Acceptable (○)", and a standard deviation greater than 0.07 was designated as "Poor (×)". As a result, the orientation uniformity of the embodiment was rated as "Good (◎)".

[0277] (3) Evaluation of DC mitigation characteristics (long-term residual image at room temperature)

[0278] Polarizing plates are attached to the outer two sides of the substrate of the liquid crystal cell manufactured in step 2, with their polarization directions orthogonal to each other and at a 45° angle to the alignment direction of the liquid crystal alignment film, thereby manufacturing an optical FFS type liquid crystal display element. The liquid crystal element is placed in an environment of 25°C and 1 atmosphere. Using a 30 Hz alternating current (AC) rectangular wave, the device is driven with 100% relative transmittance, and the brightness difference between any two pixels is set to 0. Under backlight illumination, AC driving is performed, while a 0.5 V direct current (DC) is applied to only a single pixel for 30 minutes to accumulate charge. When the DC 0.5 V application is stopped and the drive returns to AC only with 50% relative transmittance, a brightness difference is generated between the two pixels due to the accumulated charge. Regarding the brightness difference The changes over time were observed, from the end of the application of DC 0.5V until the brightness difference. The time until L becomes less than 36.8% of its initial value is defined as the afterimage erasure time. Furthermore, the shorter this time, the easier it is for the afterimage caused by the accumulated charge to disappear, and the better the electrical characteristics (DC mitigation characteristics). Regarding the evaluation, a time of less than 10 minutes is defined as "Good (◎)", a time of 10 minutes or more but less than 30 minutes is defined as "Acceptable (○)", and a time of more than 30 minutes is defined as "Poor (×)". As a result, in this embodiment, the evaluation is "Acceptable (○)".

[0279] (4) Evaluation of film strength (adhesion to the substrate)

[0280] The liquid crystal alignment agent prepared in step 1 was applied to a glass substrate using a spinner. After pre-baking at 80°C for 2 minutes, it was heated for 30 minutes in a 230°C oven purged with nitrogen (post-baking) to form a coating with an average thickness of 0.10 μm. Two coated glass substrates were prepared by repeating the same operation. On the coating of one glass substrate, ODF sealant (manufactured by Sekisui Chemicals, S-WB42) was applied with a sealant width of 1 mm. The two glass substrates were then bonded together with the ODF sealant in contact with the coating. Subsequently, the substrates were irradiated with a metal halide lamp at 30,000 J / m². 2 After being exposed to light at 365 nm (converted to standard wavelength), the film was heated in an oven at 120°C for 1 hour. Following heating, the adhesion strength was measured using a tensile and compression testing machine (model: SDWS-0201-100SL) from Imada Manufacturing Co., Ltd., to evaluate the adhesion between the film and the substrate. For the evaluation, an adhesion strength of 200 N / cm was used. 2 The above conditions are set as "Good (◎)", and 100 N / cm 2 Above but less than 200 N / cm 2 The condition is marked as "allowed (○)" and the value is less than 100 N / cm. 2 The condition is set as "Poor (×)". The result, in this embodiment, is rated as "Good (◎)".

[0281] (5) Evaluation of membrane strength (abrasion resistance)

[0282] The liquid crystal alignment agent prepared in step 1 was coated onto a glass substrate using a rotator and heated (pre-baked) for 3 minutes using a heating plate at 110°C. Subsequently, it was dried (post-baked) for 30 minutes in an oven at 230°C with nitrogen purging, forming a coating with an average thickness of 0.08 μm. The haze value of the coating was measured using a haze meter. Then, the coating was subjected to five rubbing treatments using a rubbing machine with rollers wound with cotton cloth, at a roller speed of 1000 rpm, a platform movement speed of 3 cm / s, and a bristle indentation length of 0.3 mm. The haze value of the liquid crystal alignment film was then measured using a haze meter, and the difference between the haze value and the haze value before the rubbing treatment (haze change value) was calculated. With the haze value of the film before the rubbing treatment set as Hz1 (%) and the haze value of the film after the rubbing treatment set as Hz2 (%), the haze change value is expressed by the following formula (z-2).

[0283] Haze change (%) = Hz2 - Hz1 … (z-2)

[0284] A haze change value of less than 0.5 for the liquid crystal alignment film is evaluated as "Good (◎)", a haze change value of 0.5 or more but less than 1.5 is evaluated as "Acceptable (○)", and a haze change value greater than 1.5 is evaluated as "Poor (×)". If the haze change value is 1.5 or less (more preferably less than 0.5), it can be said that the film strength is sufficiently high and the abrasion resistance is high, that is, the mechanical properties of the film are excellent. As a result, the evaluation in the described embodiment is "Good (◎)".

[0285] [Examples 2-26, Examples 28-30, and Comparative Examples 1-7]

[0286] For Examples 2, 3, 7-26, 28-30, and Comparative Examples 1-7, the liquid crystal alignment agents were prepared in the same manner as in Example 1, except that the composition of the liquid crystal alignment agent was changed as shown in Table 2. For Example 4, the solvent composition was set to γ-butyrolactam (GBL) / NMP / BC / diacetone alcohol = 40 / 30 / 10 / 20. For Example 5, the solvent composition was set to GBL / NMP / BC / N-ethyl-2-pyrrolidone = 15 / 35 / 30 / 20. For Example 6, the solvent composition was set to GBL / NMP / BC / 1,3-dimethyl-2-imidazolinone = 40 / 30 / 20 / 10. The composition of each liquid crystal alignment agent was changed as shown in Table 2. Otherwise, the liquid crystal alignment agents were prepared in the same manner as in Example 1. Furthermore, using the obtained liquid crystal alignment agent, FFS-type liquid crystal cells were manufactured by photoalignment in the same manner as in Example 1, and the retardation rate, alignment uniformity, and DC mitigation characteristics were evaluated. Additionally, using each liquid crystal alignment agent, adhesion and abrasion resistance were evaluated using the same method as in Example 1. The results are shown in Table 2.

[0287] [Example 27: Frictional FFS Type Liquid Crystal Display Element]

[0288] 1. Preparation of liquid crystal alignment agent

[0289] A solution containing 40 parts by mass of polymer (P36) obtained in Synthesis Example 36 and a solution containing 60 parts by mass of polymer (P10) obtained in Synthesis Example 10 were mixed, and NMP and BC were added to prepare a solution with a solvent composition of NMP / BC = 65 / 35 (mass ratio) and a solid content concentration of 3.5% by mass. The solution was filtered using a filter with a pore size of 0.2 μm to prepare a liquid crystal alignment agent.

[0290] 2. Manufacturing of FFS-type liquid crystal cells using the triboelectric method

[0291] Except for using the liquid crystal alignment agent prepared in 1., the glass substrate was prepared and a coating was formed in the same manner as in Example 1. The obtained coating was then subjected to friction treatment using a friction machine with rollers wound with rayon cloth, at a roller speed of 1,000 rpm, a platform movement speed of 3 cm / s, and a bristle indentation length of 0.3 mm. Subsequently, it was ultrasonically cleaned in ultrapure water for 1 minute, and then dried in a clean oven at 100°C for 10 minutes, thereby obtaining a pair of substrates with a liquid crystal alignment film.

[0292] Next, for a pair of substrates with a liquid crystal alignment film, a liquid crystal injection port is left at the edge of the surface where the liquid crystal alignment film is formed. An epoxy resin adhesive containing alumina spheres with a diameter of 3.5 μm is applied by screen printing. The substrates are then overlapped and pressed together, and the adhesive is thermosetting at 150°C for 1 hour. Then, negative liquid crystal (manufactured by Merck, MLC-6608) is filled into the gap between the two substrates through the liquid crystal injection port, and the liquid crystal injection port is sealed using an epoxy adhesive. Furthermore, to remove the flow alignment during liquid crystal injection, it is heated to 120°C and then slowly cooled to room temperature, thereby manufacturing a liquid crystal cell.

[0293] 3. Evaluation

[0294] For the liquid crystal cells manufactured in section 2, the retardation rate, alignment uniformity, and DC mitigation characteristics were evaluated using the same method as in Example 1. Additionally, the adhesion and abrasion resistance were evaluated using the liquid crystal alignment agent prepared in section 1, using the same method as in Example 1. The results are shown in Table 2.

[0295] Furthermore, in Table 2, the values ​​in the columns for polymer components (polymer 1 and polymer 2) and additives represent the mixing ratio (parts by mass) of each compound based on solid components relative to the total amount of 100 parts by mass of polymer components used in the preparation of the liquid crystal alignment agent.

[0296] [Table 2]

[0297]

[0298] As shown in Table 2, in Examples 1 to 30, the evaluation results of liquid crystal alignment agents containing polymers (P) that include structural units (U1), (U2) and (U3) within the same molecule were good (◎) or acceptable (○), and various properties were improved in a balanced manner.

[0299] The mechanism by which liquid crystal alignment agents containing polymers (P) uniformly improve liquid crystal alignment, electrical properties and film strength is still uncertain, but the following is a hypothesis.

[0300] It is hypothesized that the ionization energy is reduced by the presence of heteroatoms or aromatic heterocycles between the electron-rich aromatic rings of a specific diamine (A), or by the formation of a dense liquid crystal alignment film through the stacking of other ring structures caused by the aromatic rings of the specific diamine (A) or the cross-linking of the amino groups of the specific diamine (C), thereby increasing the charge transport properties of the liquid crystal alignment film. Therefore, it is believed that the charge accumulated in the liquid crystal alignment film is mitigated more quickly and DC residues are more easily eliminated. Furthermore, it is hypothesized that the adhesion is improved through the composite effect of the rigidity caused by the aromatic rings of the specific diamine (A), the flexibility caused by the chain structure of the specific diamine (B), and the high density of the film caused by the cross-linking of the amino groups of the specific diamine (C), and the film's defects caused by friction can be suppressed. Moreover, it is hypothesized that, as described above, the improvement in electrical properties and film strength can be achieved through the composite effect of the specific diamine (A) to the specific diamine (C), which can be achieved without compromising the anisotropy of molecular orientation on the film surface, thus maintaining good liquid crystal alignment.

[0301] In contrast, in Comparative Examples 1 to 7, which used liquid crystal alignment agents containing one or more of the following polymers (U1, U2, and U3) in the same molecule instead of polymer (P), one or more of the following evaluation results were unsatisfactory (×): retardation rate, alignment uniformity, DC mitigation characteristics, adhesion, and abrasion resistance.

[0302] Based on the above results, it is clear that by using a liquid crystal alignment agent containing a polymer (P) comprising structural units (U1), (U2), and (U3), a liquid crystal alignment film exhibiting good liquid crystal alignment properties and high film strength, as well as a liquid crystal element with excellent electrical properties, can be obtained.

Claims

1. A liquid crystal alignment agent comprising a polymer (P) containing structural units (U1), (U2) and (U3) within the same molecule. Structural unit (U1): a structural unit derived from a diamine having a partial structure represented by the following formula (1); Structural unit (U2): A structural unit derived from a diamine having the following partial structure Y, except for the structural unit (U1) and the following structural unit (U3); Structural unit (U3): a structural unit derived from a diamine having a partial structure represented by the following formula (2); Partial structure Y: The structure represented Or, a structure formed by substituting any methylene group in the represented structure with -O-, -S-, -CO-O-, -NR9-, -NR10-CO-, -NR10-CO-O-, or -NR10-CO-NR11-, where n is an integer from 2 to 20; R9 is a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms; R10 and R11 are each independently a hydrogen atom or a monovalent organic group; -O-, -S-, -CO-O-, -NR9-, -NR10-CO-, -NR10-CO-O-, and -NR10-CO-NR11- are not adjacent to each other; "1" indicates a bond formed by a single bond or a divalent organic group to a primary amino group; In equation (1), A 1 and A 2 Each is independently a trivalent aromatic cyclic group; B 1 It is a divalent aromatic heterocyclic group or -NR 1 -; in B 1 In the case of a divalent aromatic heterocyclic group, R 2 and R 3 Each can be independently a hydrogen atom or a monovalent organic group, or represent R. 2 With R 3 Combine with A 1 Divalent aromatic heterocyclic groups and A 2 A ring structure formed together; in B 1 For -NR 1 In the case of -R 1 R 2 and R 3 For example, (i) or (ii) below; (i)R 1 It is a hydrogen atom or a monovalent organic group; R 2 and R 3 Each can be independently a hydrogen atom or a monovalent organic group, or represent R. 2 With R 3 Combine with A 1 A 2 and A 1 and A 2 The ring structure formed by the bonded nitrogen atoms; (ii)R 1 and R 2 Each can be independently a hydrogen atom or a monovalent organic group, or represent R. 1 With R 2 Combine with A 1 and R 1 and A 1 The ring structure formed by the bonded nitrogen atoms; R 3 It can be a hydrogen atom or a monovalent organic group; " " represents a bond; In equation (2), X1 is a monovalent thermally degraded radical; d is 1 or 2; when d is 1, R4 is "-C(R7)(R8)-" or ">C=NR20", and when d is 2, R4 is " ",in," " indicates a bond with a nitrogen atom; R20 is a hydrogen atom or a monovalent organic group; R5 is "-C(R7)(R8)-", or a substituted or unsubstituted divalent alicyclic group; R7 and R8 are independently hydrogen atoms or substituents; R6 is a hydrogen atom, or a substituted or unsubstituted monovalent aliphatic hydrocarbon group; a is 1 or 2; b is 0 or 1; c is 0 or 1; wherein a+b+c=2; when there are two R7s, the two R7s are the same or different; when there are two R8s, the two R8s are the same or different; " " indicates a bond.

2. The liquid crystal alignment agent according to claim 1, wherein, The polymer (P) is at least one selected from the group consisting of polyamic acid, polyamic acid ester and polyimide.

3. The liquid crystal alignment agent according to claim 1, wherein, The polymer (P) has a partial structure in the main chain represented by formula (1).

4. The liquid crystal alignment agent according to claim 1, wherein, B in equation (1) 1 For -NR 1 - 5. The liquid crystal alignment agent according to claim 1, wherein, The polymer (P) contains X from formula (2) in its side chain. 1 The nitrogen atom that is bonded.

6. The liquid crystal alignment agent according to claim 1, further comprising a polymer (Q), said polymer (Q) being at least one selected from the group consisting of polyamic acid, polyamic acid ester and polyimide and different from polymer (P).

7. The liquid crystal alignment agent according to claim 6, wherein, The polymer (Q) comprises structural units derived from tetracarboxylic dianhydrides having a cyclobutane ring structure.

8. The liquid crystal alignment agent according to claim 1, wherein it contains a crosslinking agent.

9. A liquid crystal alignment film formed using a liquid crystal alignment agent as described in any one of claims 1 to 8.

10. A liquid crystal element comprising the liquid crystal alignment film as described in claim 9.

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