TECHNICAL FIELD

The present disclosure relates to polymerizable liquid crystal materials, polymerizable liquid crystal compositions, polymers, optical films, optically anisotropic bodies, polarizing plates, anti-reflection films, display devices, and methods of producing a polymerizable liquid crystal composition.

BACKGROUND

Recent improvements in the function of portable information terminals such as mobile PCs and cellular phones and their widespread use are increasingly requiring that flat panel display devices be thinned as much as possible. Correspondingly, it is also required to make thinner the retardation plates which constitute the flat panel display devices.

The method of making thinner retardation plates which is deemed most effective in recent years involves applying a polymerizable liquid crystal composition containing a polymerizable liquid crystal compound on a film substrate to form an optical film.

However, polymerizable liquid crystal compositions obtained by dissolving polymerizable liquid crystal compounds in organic solvents show poor stability and may undergo gelation with time (see, e.g., PTL 1).

CITATION LIST

Patent Literature

PTL 1: JP2011158671A

SUMMARY

Technical Problem

Therefore, there have been demands for polymerizable liquid crystal compositions which do not easily undergo gelation (i.e., have long gelation time).

Solution to Problem

The inventors made extensive studies to solve the problem set forth above and found that the conventional polymerizable liquid crystal compositions tend to undergo gelation due to the presence of certain compounds (impurities) incorporated for example during the preparation of polymerizable liquid crystal compounds. The inventors thus completed the present disclosure.

Specifically, the present disclosure aims to advantageously solve the problem set forth above and provides the polymerizable liquid crystal material, polymerizable liquid crystal composition, polymer, optical film, optically anisotropic body, polarizing plate, anti-reflection film, display device, and method of producing a polymerizable liquid crystal composition as set forth below.[1] A polymerizable liquid crystal material comprising a polymerizable liquid crystal compound, wherein

an amount of a salt represented by the following formula (I) is less than 0.01 parts by mass per 100 parts by mass of the polymerizable liquid crystal compound, and

an amount of a nitrogen-containing compound represented by the following formula (II) is 0.01 parts by mass or less per 100 parts by mass of the polymerizable liquid crystal compound,


where R1to R4each independently represent a hydrogen atom or a C1-C7 alkyl group, and X represents F−, Br−, Cl−, I−, HSO4−, 1/2(HPO42−), H2PO4−, R—C(═O)—O−, 1/2(−O—(C═O)—R′—(C═O)—O−) or R—SO3−, where R represents a hydrogen atom or a monovalent hydrocarbon group, and R′ represents a single bond or a divalent hydrocarbon group,


where R5represents a hydrogen atom or a C1-C7 alkyl group, and R6and R7represent a hydrogen atom.[2] The polymerizable liquid crystal material of [1] described above, wherein the polymerizable liquid crystal compound comprises a compound represented by the following formula (III):



where Ar represents a group represented by any of the following formulas (1) to (7) which may have a substituent:



where in formulas (1) to (7), *represents a bond with Z1or Z2,

in formulas (1) to (4), E1represents —CR11R12—, —S—, —NR11—, —C(═O)—, or —O—, in formulas (2) to (4), E2represents —CR11R12—, —S—, —NR11—, —C(═O)—, or —O—,

R11and R12each independently represent a hydrogen atom or a C1-C4 alkyl group,

in formula (1), D1represents an aromatic hydrocarbon ring group which may have a substituent, or an aromatic heterocyclic group which may have a substituent,

in formulas (2) and (3), D2and D3each independently represent an aromatic hydrocarbon ring group which may have a substituent, or an aromatic heterocyclic group which may have a substituent,

in formula (4), D4and D5each independently represent an acyclic group which may have a substituent, or an organic group in which D4and D5are combined to form a ring, and

in formulas (5) to (7), D6represents —C(Rf)═N—N(Rg)Rh, —C(Rf)═N—N═C(Rg)Rh, or —C(Rf)═N—N═Ri, where Rfrepresents a hydrogen atom or a C1-C6 alkyl group, Rgrepresents a hydrogen atom or a C1-C30 organic group which may have a substituent, Rhrepresents an organic group having one or more aromatic rings selected from the group consisting of a C6-C30 aromatic hydrocarbon ring and a C2-C30 aromatic heterocyclic ring, and Rirepresents an organic group having one or more aromatic rings selected from the group consisting of a C6-C30 aromatic hydrocarbon ring and a C2-C30 aromatic heterocyclic ring;

Z1and Z2each independently represent a single bond, —O—, —O—CH2—, —CH2—O—, —O—CH2—CH2—, —CH2—CH2—O—, —C(═O)—O—, —O—C(═O)—, —C(═O)—S—, —S—C(═O)—, —NR21—C(═O)—, —C(═O)—NR21—, —CF2—O—, —O—CF2—, —CH2—CH2—, —CF2—CF2—, —O—CH2—CH2—O—, —CH═CH—C(═O)—O—, —O—C(═O)—CH═CH—, —CH2—C(═O)—O—, —O—C(═O)—CH2—, —CH2—O—C(═O)—, —C(═O)—O—CH2—, —CH2—CH2—C(—O)—O—, —O—C(═O)—CH2—CH2—, —CH2—CH2—O—C(—O)—, —C(═O)—O—CH2—CH2—, —CH═CH—, —N═CH—, —CH═N—, —N═C(CH3)—, —C(CH3)═N—, —N═N—, or, —C≡C—, where R21represents a hydrogen atom or a C1-C6 alkyl group;

A1, A2, B1and B2each independently represent a cyclic aliphatic group which may have a substituent, or an aromatic group which may have a substituent;

Y1to Y4each independently represent a single bond, —O—, —C(═O)—, —C(═O)—O—, —O—C(═O)—, —NR22—C(═O)—, —C(═O)—NR22—, —O—C(═O)—O—, —NR22—C(═O)—O—, —O—C(═O)—NR22—, or —NR22—C(═O)—NR23—, where R22and R23each independently represent a hydrogen atom or a C1-C6 alkyl group;

G1and G2each independently represent an organic group which is either a C1-C20 aliphatic hydrocarbon group or a C3-C20 aliphatic hydrocarbon group in which one or more methylene groups (—CH2—) are replaced by —O— or —C(═O)—, where one or more hydrogen atoms of the organic group may be replaced by a C1-C5 alkyl group, a C1-C5 alkoxy group or a halogen atom, with the proviso that methylene groups (—CH2—) at both ends of each of G1and G2are not replaced by —O— or —C(═O)—;

P1and P2each independently represent a polymerizable group; and

p and q each independently represent 0 or 1.[3] A polymerizable liquid crystal composition comprising the polymerizable liquid crystal material of [1] or [2] described above, and an organic solvent.[4] The polymerizable liquid crystal composition of [3] described above, further comprising at least one of a surfactant and a polymerization initiator.[5] A polymer obtainable by polymerizing the polymerizable liquid crystal material of [1] or [2] described above.[6] An optical film comprising the polymer of [5] described above as a constituent material.[7] An optically anisotropic body comprising the polymer of [5] described above as a constituent material.[8] A polarizing plate comprising the optically anisotropic body of [7] described above and a polarizing film.[9] A display device comprising the polarizing plate of [8] described above.[10] An anti-reflection film comprising the polarizing plate of [8] described above.[11]. A method of producing a polymerizable liquid crystal composition, comprising:

a first step of confirming that a polymerizable liquid crystal material which comprises a polymerizable liquid crystal compound comprises less than 0.01 parts by mass of a salt represented by the following formula (I) per 100 parts by mass of the polymerizable liquid crystal compound, and 0.01 parts by mass or less of a nitrogen-containing compound represented by the following formula (II) per 100 parts by mass of the polymerizable liquid crystal compound; and

a second step of mixing the polymerizable liquid crystal material with an organic solvent after the first step,


where R1to R4each independently represent a hydrogen atom or a C1-C7 alkyl group, and X represents F−, Br−, HSO4−, 1/2(HPO42−), H2PO4−, R—C(═O)—O−, 1/2(−O—(C═O)—R′—(C═O)—O−) or R—SO3−, where R represents a hydrogen atom or a monovalent hydrocarbon group, and R′ represents a single bond or a divalent hydrocarbon group,


where R5represents a hydrogen atom or a C1-C7 alkyl group, and R6and R7represent a hydrogen atom.

Advantageous Effect

According to the present disclosure, it is possible to provide a polymerizable liquid crystal composition which does not easily undergo gelation (i.e., has long gelation time) and a polymerizable liquid crystal material from which the polymerizable liquid crystal composition can be prepared.

According to the present disclosure, it is also possible to provide a polymer obtainable by polymerizing the polymerizable liquid crystal material, an optical film and an optically anisotropic body which comprise the polymer, and a polarizing plate, an anti-reflection film and a display device which comprise the optically anisotropic body.

