TWI869565B - Polymerizable liquid crystal composition, phase difference film, elliptical polarizing plate and optical display - Google Patents

Abstract

The polymerizable liquid crystal composition of the present invention comprises at least two polymerizable liquid crystal compounds represented by formula (1) having the same molecular weight but different molecular structures. The above-mentioned polymerizable liquid crystal compound includes: a polymerizable liquid crystal compound (1-1) in which ^G1 and ^G2 in formula (1) are respectively 1,4-trans-cyclohexanediyl, and a polymerizable liquid crystal compound (1-2) having a molecular structure different from that of the above-mentioned polymerizable liquid crystal compound (1-1) only when at least one of ^G1 and G2 in formula (1 ⁾ is 1,4-cis-cyclohexanediyl; the ratio of the peak area of the polymerizable liquid crystal compound (1-2) measured by liquid chromatography to the total peak area of the polymerizable liquid crystal compound (1-1) and the polymerizable liquid crystal compound (1-2) is greater than 0.01% and less than 10%.

Description

Polymerizable liquid crystal composition, phase difference film, elliptical polarizing plate and optical display

The present invention relates to a polymerizable liquid crystal composition, a phase difference film comprising a cured product of the polymerizable liquid crystal composition, and an elliptical polarizing plate and an optical display comprising the phase difference film.

As an optical film such as a phase difference film used in a flat panel display device (FPD), there is an optical film, for example, which is obtained by dissolving a polymerizable liquid crystal compound in a solvent to obtain a coating liquid, applying the obtained coating liquid to a supporting substrate, and then polymerizing it. As a polymerizable liquid crystal compound used to form such an optical film, for example, a nematic liquid crystal compound having a rod-like structure with 2 to 4 six-membered rings connected is known.

On the other hand, the phase difference film is required to be able to perform uniform polarization conversion in the entire wavelength range as one of its characteristics. It is known that in the wavelength range where the value [Re(λ)/Re(550)] obtained by dividing the phase difference value Re(λ) at a certain wavelength λ by the phase difference value Re(550) at 550 nm is close to 1, and in the wavelength range showing the reverse wavelength dispersion of [Re(450)/Re(550)] < 1, it is theoretically possible to perform uniform polarization conversion. The polymerizable liquid crystal compound that can constitute such a phase difference film is disclosed in, for example, Japanese Patent Publication No. 2011-207765 and Japanese Patent Publication No. 2015-143788.

In a solution (coating liquid) for manufacturing an optical film obtained by dissolving a polymerizable liquid crystal compound in a solvent, the solubility in various solvents is sometimes insufficient due to the molecular structure of the polymerizable liquid crystal compound. Such a polymerizable liquid crystal compound with low solubility sometimes precipitates or crystallizes and precipitates in the coating liquid, and such precipitation and precipitation of the polymerizable liquid crystal compound may cause a decrease in film forming properties and alignment defects in the obtained optical film. Therefore, it is expected to develop a polymerizable liquid crystal composition containing a polymerizable liquid crystal that exhibits further improved solubility in a solvent.

The object of the present invention is to provide a polymerizable liquid crystal composition having excellent solubility in a solvent.

The present invention provides the following suitable aspects.

[1] A polymerizable liquid crystal composition comprising at least two polymerizable liquid crystal compounds represented by formula (1) having the same molecular weight but different molecular structures [In the formula (1), Ar represents a divalent aromatic hydrocarbon group or a divalent aromatic heterocyclic group which may have a substituent, D ¹ , D ² , E ¹ , E ² , B ¹ and B ² each independently represent -CR ¹¹ R ¹² -, -CH ₂ -CH ₂ -, -O-, -S-, -CO-O-, -O-CO-, -O-CO-O-, -C(=S)-O-, -OC(=S)-, -OC(=S)-O-, -CO-NR ¹¹ -, -NR ¹¹ -CO-, -O-CH ₂ -, -CH ₂ -O-, -S-CH 2 -, -CH ₂ -S- or a single bond, R ¹¹ and R ¹² each independently represent a hydrogen atom, a fluorine atom or an alkyl group having 1 to 4 carbon atoms, G ¹ and G 2 each independently represent -CR 11 R 12 -, -CH ₂ -CH 2 -, -O-, -S- ^A1 and ^A2 each independently represent a divalent alicyclic alkyl group having 3 to 16 carbon atoms or a divalent ^aromatic alkyl group having 6 to 20 carbon atoms, wherein the hydrogen atom contained in the alicyclic alkyl group and the aromatic alkyl group may be substituted by a halogen atom, ^-R13 , ^-OR13 , a cyano group or a nitro group, ^R13 represents an alkyl group having 1 to 4 carbon atoms, wherein the hydrogen atom contained in the alkyl group may be substituted by a fluorine atom, ^F1 and ^F2 each independently represent an alkanediyl group having 1 to 12 carbon atoms, wherein the hydrogen atom contained in the alkanediyl group may be substituted by ^-OR14 or a halogen atom, ^R14 represents an alkyl group having 1 to 4 carbon atoms, wherein the hydrogen atom contained in the alkyl group may be substituted by a fluorine atom, and the _-CH2- contained in the alkanediyl group may be substituted by -O- or -CO-, ^P1 and ^P2 each independently represent a hydrogen atom or a polymerizable group (wherein at least one of ^P1 and ^P2 is a polymerizable group)], as the above-mentioned polymerizable liquid crystal compound, it includes: a polymerizable liquid crystal compound (1-1 ⁾ in which ^G1 and ^G2 in formula (1) are each 1,4-trans-cyclohexanediyl, and a polymerizable liquid crystal compound (1-2) having a molecular structure different from that of the above-mentioned polymerizable liquid crystal compound (1-1) only when at least one of ^G1 and G2 in formula (1) is 1,4-cis-cyclohexanediyl; the ratio of the peak area of the polymerizable liquid crystal compound (1-2) measured by liquid chromatography to the total peak area of the polymerizable liquid crystal compound (1-1) and the polymerizable liquid crystal compound (1-2) is greater than 0.01% and less than 10%. [2] The polymerizable liquid crystal composition described in [1] above, wherein the polymerizable liquid crystal compound (1-2) comprises a polymerizable liquid crystal compound (1-2a) in which any one of ^G1 and ^G2 in formula (1) is 1,4-cis-cyclohexanediyl, and a polymerizable liquid crystal compound (1-2b) in which ^G1 and ^G2 in formula (1) are both 1,4-cis-cyclohexanediyl. [3] The polymerizable liquid crystal composition described in [1] or [2] above, wherein Ar in formula (1) is a group represented by any one of formulas (2-1) to (2-5). [wherein, * represents a bonding portion with D ¹ or D ² ; Q ¹ represents -S-, -O- or -NR ¹⁵ -, R ¹⁵ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms which may have a substituent, Q ² represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms which may have a substituent; W ¹ and W ² each independently represent -O-, -S-, -CO- or -NR ¹⁵ -, R ¹⁵ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms which may have a substituent; Y ¹ represents an alkyl group having 1 to 6 carbon atoms, an aromatic alkyl group or an aromatic heterocyclic group which may have a substituent, the hydrogen atom contained in the alkyl group, the aromatic alkyl group or the aromatic heterocyclic group may be substituted by a halogen atom, the -CH ₂ - contained in the alkyl group may be substituted by -O-, -CO-, -O-CO- or -CO-O-, Y ^Z2 represents a CN group or an alkyl group having 1 to 12 carbon atoms which may have a substituent. The hydrogen atom contained in the alkyl group may be substituted by a halogen atom, and the _-CH2- contained in the alkyl group may be substituted by -O-, -CO-, -O-CO- or -CO-O-; ^Z1 , ^Z2 and ^Z3 each independently represent a hydrogen atom or an aliphatic hydrocarbon group or alkoxy group having 1 to 20 carbon atoms, an alicyclic hydrocarbon group having 3 to 20 carbon atoms, a monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms, a halogen atom, a cyano group, a nitro group, ^-NR15R16 or ^-SR15 ; ^Z1 and ^Z2 may also be bonded to each other to form an aromatic ring or an aromatic heterocyclic ring; ^R15 and ^R16 each independently represent a hydrogen atom or an alkyl group having 1 to ⁶ carbon atoms; Ax represents an organic group having 2 to 30 carbon atoms and at least one aromatic ring selected from the group consisting of aromatic hydrocarbon rings and aromatic heterocyclic rings; Ay represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms which may have a substituent, or an organic group having 2 to 30 carbon atoms and at least one aromatic ring selected from the group consisting of aromatic hydrocarbon rings and aromatic heterocyclic rings; Ax and Ay may also be bonded to form a ring; ^Y3 and ^Y4 each independently represent a group selected from the following formula (Y-1): [In formula (Y-1), ^M1 represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and the alkyl group may be substituted by one or more substituents ^X3 , and the substituents ^X3 represent fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, pentafluorosulfur groups, nitro groups, cyano groups, isocyano groups, amino groups, hydroxyl groups, hydroxyl groups, methylamino groups, dimethylamino groups, diethylamino groups, diisopropylamino groups, trimethylsilyl groups, dimethylsilyl groups, isothiocyano groups, or one _-CH2- or two or more non-adjacent -CH2- _groups. - a linear or branched alkyl group having 1 to 20 carbon atoms which may be independently substituted by -O-, -S-, -CO-, -COO-, -OCO-, -CO-S-, -S-CO-, -O-CO-O-, -CO-NH-, -NH-CO-, -CH=CH-COO-, -CH=CH-OCO-, -COO-CH=CH-, -OCO-CH=CH-, -CH=CH-, -CF=CF- or -C≡C-, any hydrogen atom in the alkyl group may be substituted by a fluorine atom, or may be a group represented by ^-B11 - ^F11 - ^P11 , ^B11 , ^F11 and ^P11 are respectively defined as ^B1 , ^F1 and ^P1 in the above formula (1), and may be respectively substituted by ^B1 , ^F1 and P1 as above. ¹ are the same or different; U ¹ represents an organic group having 2 to 30 carbon atoms and having an aromatic hydrocarbon group, any carbon atom of the aromatic hydrocarbon group may be substituted by a heteroatom, and the aromatic hydrocarbon group may be substituted by one or more of the substituents X ³ mentioned above; T ¹ represents -O-, -S-, -COO-, -OCO-, -OCO-O-, -NU ² -, -N=CU ² -, -CO-NU ² -, -OCO-NU ² -, or -O-NU ² -, and U ² represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 12 carbon atoms, a cycloalkenyl group having 3 to 12 carbon atoms, an organic group having 2 to 30 carbon atoms and having an aromatic hydrocarbon group (any carbon atom of the aromatic hydrocarbon group may be substituted by a heteroatom), or (E ¹¹ -A ¹¹ ) _q -B ¹² -F ¹² -P ¹² , the alkyl, cycloalkyl, cycloalkenyl and aromatic hydrocarbon group are unsubstituted or substituted with one or more substituents X ³ , the alkyl group may be substituted with the cycloalkyl or cycloalkenyl group, one -CH ₂ - or two or more non-adjacent -CH ₂ - in the alkyl group may be independently substituted with -O-, -S-, -CO-, -COO-, -OCO-, -CO-S-, -S-CO-, -SO _{2 -, -O-CO-O-, -CO-NH-, -NH-CO-, -CH=CH-COO-, -CH=CH-OCO-, -COO-CH=CH-, -OCO-CH=CH-, -CH=CH-, -CF=CF- or -C≡C-, one -CH 2} in the cycloalkyl or cycloalkenyl group may be substituted with -O-, -S-, -CO-, -COO-, -OCO-, -CO-S-, -S-CO-, -SO 2 -, -O-CO-O-, -CO-NH-, -NH-CO-, -CH=CH-COO-, -CH=CH-OCO-, -COO-CH=CH-, -OCO- _CH =CH-, -CH=CH-, -CF=CF- or -C≡C- - or two or more non-adjacent -CH ₂ - may be independently substituted with -O-, -CO-, -COO-, -OCO- or -O-CO-O-; E ¹¹ , A ¹¹ , B ¹² , F ¹² and P ¹² are defined similarly to E ¹ , A ¹ , B ¹ , F ¹ and P ¹ in formula (1), and may be the same as or different from the above-mentioned E ¹ , A ¹ , B ¹ , F ¹ and P ¹ , respectively; q represents an integer of 0 to 4, and when there are plural E ¹¹ and/or A ¹¹ , they may be the same as or different; U ¹ and U ² may be bonded to form a ring]]. [4] The polymerizable liquid crystal composition described in any one of [1] to [3] above, wherein ^A1 and ^A2 in formula (1) are independently 1,4-cyclohexanediyl or 1,4-phenylenediyl. [5] The polymerizable liquid crystal composition described in any one of [1] to [4] above, wherein ^P1 and ^P2 in formula (1) are acryloyl. [6] The polymerizable liquid crystal composition described in any one of [1] to [5] above, further comprising a photopolymerization initiator. [7] The polymerizable liquid crystal composition described in any one of [1] to [6] above, further comprising an organic solvent. [8] A phase difference film comprising a liquid crystal cured film as a cured product of the polymerizable liquid crystal composition described in any one of [1] to [7] above. [9] A phase difference film as described in [8] above, wherein the liquid crystal cured film satisfies formula (i): 0.75≦Re(450)/Re(550)＜1.00 (i) [In formula (i), Re(λ) represents the in-plane phase difference value of the liquid crystal cured film at a wavelength of λ nm]. [10] An elliptical polarizing plate comprising the phase difference film as described in [8] or [9] above. [11] An optical display comprising the elliptical polarizing plate as described in [10] above. [12] A flexible image display device comprising the elliptical polarizing plate as described in [10] above.

According to the present invention, a polymerizable liquid crystal composition having excellent solubility in a solvent can be provided.

The following is a detailed description of the implementation of the present invention. Furthermore, the scope of the present invention is not limited to the implementation described here, and various modifications can be made within the scope of not damaging the gist of the present invention.

<Polymerizable liquid crystal composition> The polymerizable liquid crystal composition of the present invention comprises at least two polymerizable liquid crystal compounds represented by formula (1) having the same molecular weight but different molecular structures. By comprising at least two polymerizable liquid crystal compounds having different molecular structures but the same molecular weight and having molecular structures similar to each other represented by formula (1), high solubility in a solvent can be ensured. [In the formula (1), Ar represents a divalent aromatic hydrocarbon group or a divalent aromatic heterocyclic group which may have a substituent, D ¹ , D ² , E ¹ , E ² , B ¹ and B ² each independently represent -CR ¹¹ R ¹² -, -CH ₂ -CH ₂ -, -O-, -S-, -CO-O-, -O-CO-, -O-CO-O-, -C(=S)-O-, -OC(=S)-, -OC(=S)-O-, -CO-NR ¹¹ -, -NR ¹¹ -CO-, -O-CH ₂ -, -CH ₂ -O-, -S-CH 2 -, -CH ₂ -S- or a single bond, R ¹¹ and R ¹² each independently represent a hydrogen atom, a fluorine atom or an alkyl group having 1 to 4 carbon atoms, G ¹ and G 2 each independently represent -CR 11 R 12 -, -CH ₂ -CH 2 -, -O-, -S- ^A1 and ^A2 each independently represent a divalent alicyclic alkyl group having 3 to 16 carbon atoms or a divalent ^aromatic alkyl group having 6 to 20 carbon atoms, wherein the hydrogen atom contained in the alicyclic alkyl group and the aromatic alkyl group may be substituted by a halogen atom, ^-R13 , ^-OR13 , a cyano group or a nitro group, ^R13 represents an alkyl group having 1 to 4 carbon atoms, wherein the hydrogen atom contained in the alkyl group may be substituted by a fluorine atom, ^F1 and ^F2 each independently represent an alkanediyl group having 1 to 12 carbon atoms, wherein the hydrogen atom contained in the alkanediyl group may be substituted by ^-OR14 or a halogen atom, ^R14 represents an alkyl group having 1 to 4 carbon atoms, wherein the hydrogen atom contained in the alkyl group may be substituted by a fluorine atom, and the _-CH2- contained in the alkanediyl group may be substituted by -O- or -CO-, ^P1 and ^P2 each independently represent a hydrogen atom or a polymerizable group (wherein at least one of ^P1 and ^P2 is a polymerizable group)].

The polymerizable liquid crystal composition of the present invention includes, as the at least two polymerizable liquid crystal compounds, a polymerizable liquid crystal compound (1-1) in which ^G1 and ^G2 in formula (1) are 1,4-trans-cyclohexanediyl (hereinafter also referred to as "polymerizable liquid crystal compound (1-1)"), and a polymerizable liquid crystal compound (1-2) having a molecular structure different from that of the polymerizable liquid crystal compound (1-1) only when at least one of ^G1 and G2 in formula ( ¹⁾ is 1,4-cis-cyclohexanediyl (hereinafter also referred to as "polymerizable liquid crystal compound (1-2)"). In the present invention, the polymerizable liquid crystal composition may include only one polymerizable liquid crystal compound (1-1) or two or more. When a plurality of polymerizable liquid crystal compounds (1-1) are included, the polymerizable liquid crystal composition of the present invention may include a polymerizable liquid crystal compound (1-2) corresponding to at least one of the polymerizable liquid crystal compounds (1-1), or may include polymerizable liquid crystal compounds (1-2) respectively corresponding to the plurality of polymerizable liquid crystal compounds (1-1) constituting the polymerizable liquid crystal composition.

By including the polymerizable liquid crystal compound (1-1) in combination with the polymerizable liquid crystal compound (1-2) whose molecular structure is different only when at least one of ^G1 and ^G2 in the formula (1) is 1,4-cis-cyclohexanediyl, i.e., as an isomer, the solubility of the polymerizable liquid crystal compound (1-1) in the solvent can be improved. That is, when the polymerizable liquid crystal compound (1-1) and the polymerizable liquid crystal compound (1-2) are included in combination, a larger amount of the polymerizable liquid crystal compound (1-1) can be easily dissolved in the same amount or a smaller amount of the solvent compared to the case where the polymerizable liquid crystal compound (1-1) is dissolved in the solvent alone. In this way, undissolved polymerizable liquid crystal compounds are less likely to remain in the coating solution, and precipitation, precipitation and accumulation of polymerizable liquid crystal compounds in the coating solution can be suppressed. The improvement of the solubility of the polymerizable liquid crystal compound (1-1) in the solvent is related to the suppression of alignment defects caused by undissolved polymerizable liquid crystal compounds and precipitates, and the improvement of storage stability.

The polymerizable liquid crystal compound (1-1) and the polymerizable liquid crystal compound (1-2) are respectively represented by formula (1): The polymerizable liquid crystal compound represented by formula (1) is a polymerizable liquid crystal compound that exhibits reverse wavelength dispersion birefringence when polymerized in a state of being aligned in one direction, and is capable of uniform polarization conversion in a relatively wide wavelength range. Therefore, by using the polymerizable liquid crystal compound represented by formula (1), a polymerizable liquid crystal composition can be obtained that can impart good display characteristics when a phase difference film and an elliptical polarizing plate formed by the polymerizable liquid crystal compound are used in an optical display such as a display device.

In formula (1), ^G1 and ^G2 each independently represent a 1,4-cyclohexanediyl group. The two polymerizable liquid crystal compounds (1-1) and the polymerizable liquid crystal compound (1-2) constituting the polymerizable liquid crystal composition of the present invention are different from each other in that the structures represented by ^G1 and ^G2 in formula (1) are all 1,4-trans-cyclohexanediyl groups, or that any one or all of ^G1 and ^G2 are 1,4-cis-cyclohexanediyl groups.

In formula (1), D ¹ , D ² , E ¹ , E ² , B ¹ and B ² each independently represent -CR ¹¹ R ¹² -, -CH ₂ -CH ₂ -, -O-, -S-, -CO-O-, -O-CO-, -O-CO-O-, -C(=S)-O-, -OC(=S)-, -OC(=S)-O-, -CO-NR ¹¹ -, -NR ¹¹ -CO-, -O-CH _{2 -, -CH 2} -O-, -S-CH ₂ -, -CH _{2 -S-} or a single bond. Here, R ¹¹ and R ¹² each independently represent a hydrogen atom, a fluorine atom or an alkyl group having 1 to 4 carbon atoms, preferably a hydrogen atom, a methyl group or an ethyl group.

In formula (1), ^D1 and ^D2 are each independently preferably -CO-O-, -O-CO-, -C(=S)-O-, -OC(=S)-, -O- _CH2- , -CH2-O-, -CO- _NR11- or ^-NR11 -CO-, more preferably -CO-O-, -O-CO-, -CO- ^NR11- or ^-NR11 -CO-, and particularly preferably -CO-O- or ^-O -CO-. ^R11 is preferably a hydrogen atom, a methyl group or an ethyl group. In formula (1), ^D1 and ^D2 may be the same or different. Furthermore, ^D1 and ^D2 being the same means that the structures of ^D1 and ^D2 are the same when observed with Ar as the center. The same applies to the relationships between ^E1 and ^E2 , ^A1 and ^A2 , ^B1 and ^B2 , and ^F1 and ^F2 .

In formula (1), ^E1 , ^E2 , ^B1 and ^B2 are each independently preferably -O-, -S-, -CO-O-, -O-CO-, -O-CO-O-, -CO- ^NR11- , ^-NR11 -CO- or a single bond, and more preferably -O-, -O-CO- or -CO-O-. ^R11 is preferably a hydrogen atom, a methyl group or an ethyl group. In formula (1), ^E1 and ^E2 , and ^B1 and ^B2 may be the same or different.

In formula (1), ^A1 and ^A2 each independently represent a divalent alicyclic alkyl group having 3 to 16 carbon atoms or a divalent aromatic alkyl group having 6 to 20 carbon atoms. Here, the hydrogen atom contained in the alicyclic alkyl group and the aromatic alkyl group may be substituted by a halogen atom, ^-R13 , ^-OR13 , a cyano group or a nitro group, and ^R13 represents an alkyl group having 1 to 4 carbon atoms, and the hydrogen atom contained in the alkyl group may be substituted by a fluorine atom.

In formula (1), ^A1 and ^A2 are each independently preferably 1,4-phenylenediyl which may be substituted by at least one substituent selected from the group consisting of a halogen atom and an alkyl group having 1 to 4 carbon atoms, 1,4-cyclohexanediyl which may be substituted by at least one substituent selected from the group consisting of a halogen atom and an alkyl group having 1 to 4 carbon atoms, more preferably 1,4-phenylenediyl substituted by methyl, unsubstituted 1,4-phenylenediyl, or unsubstituted 1,4-cyclohexanediyl, particularly preferably unsubstituted 1,4-phenylenediyl or unsubstituted 1,4-cyclohexanediyl, and particularly preferably unsubstituted 1,4-phenylenediyl. In formula (1), ^A1 and ^A2 may be the same or different.

In formula (1), ^F1 and ^F2 each independently represent an alkanediyl group having 1 to 12 carbon atoms. Here, the hydrogen atom contained in the alkanediyl group may be substituted by ^-OR14 or a halogen atom, and ^R14 represents an alkyl group having 1 to 4 carbon atoms, and the hydrogen atom contained in the alkyl group may be substituted by a fluorine atom. In addition, the _-CH2- contained in the alkanediyl group may be substituted by -O- or -CO- (wherein, when there are plural -O- groups, they are not adjacent to each other).

In formula (1), ^F1 and ^F2 are each independently preferably an optionally substituted alkanediyl group having 4 to 12 carbon atoms. In formula (1), ^F1 and ^F2 may be the same or different from each other.

Examples of the polymerizable group represented by ^P1 or ^P2 include epoxy, vinyl, vinyloxy, 1-chlorovinyl, isopropenyl, 4-vinylphenyl, acryl, methacryl, oxirane and cyclobutyl. Among them, acryl, methacryl, vinyl and vinyloxy are preferred, acryl and methacryl are more preferred, and acryl is further preferred. In formula (1), ^P1 and ^P2 may be the same or different as long as either one of them is a polymerizable group, but preferably both ^P1 and ^P2 are polymerizable groups, and more preferably both ^P1 and ^P2 are acryl.

In formula (1), Ar represents a divalent aromatic alkyl group or a divalent aromatic heterocyclic group which may have a substituent. In the present invention, a divalent aromatic alkyl group which may have a substituent refers to a divalent linking group containing at least one aromatic alkyl ring, and a divalent aromatic heterocyclic group which may have a substituent refers to a divalent linking group containing at least one aromatic heterocyclic ring. The aromatic alkyl ring and aromatic heterocyclic ring mentioned here refer to those having a ring structure having a π electron number of [4n+2] (n represents an integer) according to Huckel's rule (in the case of an aromatic heterocyclic ring, non-shared bonding electron pairs on hetero atoms such as -N= and -S- are included to satisfy Huckel's rule). Ar may contain one aromatic hydrocarbon ring or an aromatic heterocyclic ring, or may contain two or more. When containing one aromatic hydrocarbon ring or an aromatic heterocyclic ring, Ar may be a divalent aromatic hydrocarbon group which may have a substituent, or may be a divalent aromatic heterocyclic group which may have a substituent. When containing two or more aromatic hydrocarbon rings or aromatic heterocyclic rings, it may contain only a plurality of aromatic hydrocarbon rings, or only a plurality of aromatic heterocyclic rings, or may contain one or more aromatic hydrocarbon rings and aromatic heterocyclic rings respectively. Two or more aromatic hydrocarbon rings and/or aromatic heterocyclic rings may be bonded to each other via a single bond, a divalent bonding group such as -CO-O-, or -O-.

Examples of aromatic hydrocarbon rings that Ar may contain include benzene ring, naphthalene ring, anthracene ring, etc., preferably benzene ring and naphthalene ring. Examples of aromatic heterocyclic rings include furan ring, benzofuran ring, pyrrole ring, indole ring, thiophene ring, benzothiophene ring, pyridine ring, pyrrolidine ring, pyrimidine ring, triazole ring, tris(iodine) ring, pyrroline ring, imidazole ring, pyrazole ring, thiazole ring, benzothiazole ring, thiophenothiazole ring, oxadiazole ring, benzooxadiazole ring, and phenanthroline ring. When Ar contains a nitrogen atom, the nitrogen atom preferably has π electrons.

Among them, Ar is preferably an aromatic heterocyclic ring containing at least two heteroatoms selected from the group consisting of nitrogen atoms, oxygen atoms and sulfur atoms, more preferably a thiazole ring, a benzothiazole ring or a benzofuran ring, and more preferably a benzothiazole ring. Furthermore, when Ar has an aromatic heterocyclic ring containing at least two heteroatoms selected from the group consisting of nitrogen atoms, oxygen atoms and sulfur atoms, the aromatic heterocyclic ring may be directly bonded to ^D1 and ^D2 in formula (1) to form a divalent linking group, or may be included as a substituent of the divalent linking group directly bonded to ^D1 and ^D2 , but it is preferred that the Ar group containing the aromatic heterocyclic ring as a whole is stereoscopically configured in a direction substantially orthogonal to the molecular orientation direction.

In formula (1), the total number _Nπ of π electrons contained in the divalent aromatic alkyl group or divalent aromatic heterocyclic group which may have a substituent represented by Ar is preferably 8 or more, more preferably 12 or more, particularly preferably 16 or more, and particularly preferably 20 or more. Further, it is preferably 36 or less, more preferably 32 or less, further preferably 30 or less, particularly preferably 26 or less, and particularly preferably 24 or less.

Examples of the divalent aromatic alkyl group or divalent aromatic heterocyclic group which may have a substituent and which is represented by Ar in the formula (1) include groups represented by the following formulae (2-1) to (2-5).

In formulas (2-1) to (2-5), * represents a bonding portion with ^D1 or ^D2 .

In formula (2-1), ^Q1 represents -S-, -O- or ^-NR15- , and ^R15 represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms which may have a substituent. In formula (2-3) and (2-4), ^Q2 represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms which may have a substituent.

In formula (2-2), ^W1 and ^W2 independently represent -O-, -S-, -CO-, or ^-NR15- , and ^R15 represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms which may have a substituent.

In formula (2-1), ^Y1 represents an alkyl group having 1 to 6 carbon atoms, an aromatic alkyl group or an aromatic heterocyclic group which may have a substituent, preferably an aromatic alkyl group having 6 to 12 carbon atoms or an aromatic heterocyclic group which may have a substituent, and more preferably an aromatic alkyl group having 6 to 12 carbon atoms or an aromatic heterocyclic group which may have a substituent. In formula (2-2), ^Y2 represents a CN group or an alkyl group having 1 to 12 carbon atoms which may have a substituent. Here, the hydrogen atom contained in the alkyl group, the aromatic heterocyclic group or the aromatic heterocyclic group may be substituted with a halogen atom, and _-CH2- contained in the alkyl group may be substituted with -O-, -CO-, -O-CO- or -CO-O-.

In formulae (2-1) to (2-5), Z ¹ , Z ² and Z ³ independently represent a hydrogen atom, an aliphatic alkyl group or an alkoxy group having 1 to 20 carbon atoms, an alicyclic alkyl group having 3 to 20 carbon atoms, a monovalent aromatic alkyl group having 6 to 20 carbon atoms, a halogen atom, a cyano group, a nitro group, -NR ¹⁵ R ¹⁶ or -SR ¹⁵ . Z ¹ and Z ² may be bonded to each other to form an aromatic ring or an aromatic heterocyclic ring. R ¹⁵ and R ¹⁶ independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.

In formulae (2-3) and (2-4), Ax represents an organic group having 2 to 30 carbon atoms and having at least one aromatic ring selected from the group consisting of aromatic hydrocarbon rings and aromatic heterocyclic rings, and Ay represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms which may have a substituent, or an organic group having 2 to 30 carbon atoms and having at least one aromatic ring selected from the group consisting of aromatic hydrocarbon rings and aromatic heterocyclic rings. Ax and Ay may also be bonded to form a ring.

The groups represented by formulae (2-1) to (2-4) are not particularly limited, and specific examples thereof include groups described in Japanese Patent Application Publication No. 2011-207765, Japanese Patent Application Publication No. 2008-107767, and WO2014/010325.

In formula (2-5), Y ³ and Y ⁴ are independently selected from the following formula (Y-1): The basis represented.

In formula (Y-1), ^M1 represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. The alkyl group may be substituted by one or more substituents ^X3 .

The substituent X ³ represents a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a pentafluorosulfur group, a nitro group, a cyano group, an isocyano group, an amino group, a hydroxyl group, an amine group, a methylamino group, a dimethylamino group, a diethylamino group, a diisopropylamino group, a trimethylsilyl group, a dimethylsilyl group, an isothiocyano group, or one -CH ₂ - or two or more non-adjacent -CH ₂ - a linear or branched alkyl group having 1 to 20 carbon atoms which may be independently substituted by -O-, -S-, -CO-, -COO-, -OCO-, -CO-S-, -S-CO-, -O-CO-O-, -CO-NH-, -NH-CO-, -CH=CH-COO-, -CH=CH-OCO-, -COO-CH=CH-, -OCO-CH=CH-, -CH=CH-, -CF=CF- or -C≡C-, any hydrogen atom in the alkyl group may be substituted by a fluorine atom, or may be a group represented by ^-B11 - ^F11 - ^P11 , ^B11 , ^F11 and ^P11 are respectively defined as ^B1 , ^F1 and ^P1 in the above formula (1), and may be respectively substituted by ^B1 , ^F1 and P1 as above. ^1Same , or different.

The substituent X ³ is preferably a fluorine atom, a chlorine atom, -CF ₃ , -OCF ₃ or a cyano group. M ¹ is preferably unsubstituted, or a hydrogen atom or an alkyl group having 1 to 6 carbon atoms substituted with one or more fluorine atoms, more preferably a hydrogen atom.

^U1 represents an organic group having 2 to 30 carbon atoms and having an aromatic alkyl group. Any carbon atom of the aromatic alkyl group may be substituted with a heteroatom, and ^U1 is an organic group having 2 to 30 carbon atoms and having at least one aromatic ring selected from the group consisting of an aromatic alkyl ring and an aromatic heterocyclic ring. The aromatic alkyl group may be substituted with one or more of the above-mentioned substituents ^X3 .

In order to improve the wavelength dispersion, ^U1 is preferably an organic group having an aromatic heterocyclic ring in which one or more carbon atoms are substituted by heteroatoms. In order to improve the wavelength dispersion and show higher birefringence, ^U1 is more preferably an organic group having an aromatic heterocyclic ring as a condensed ring of a five-membered ring and a six-membered ring.

Specifically, U ¹ is preferably a group represented by the following formula: In the following formula, the group has a bond with T ¹ at any position.

^T1 represents -O-, -S-, -COO-, -OCO-, -OCO-O-, ^-NU2- , -N= ^CU2- , -CO- ^NU2- , -OCO- ^NU2- , or -O- ^NU2- , and ^U2 represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 12 carbon atoms, a cycloalkenyl group having 3 to 12 carbon atoms, an organic group having 2 to 30 carbon atoms having an aromatic hydrocarbon group (any carbon atom of the aromatic hydrocarbon group may be substituted with a heteroatom), or ( ^E11 - ^A11 ) _q - ^B12 - ^F12 - ^P12 . The above-mentioned alkyl group, cycloalkyl group, cycloalkenyl group, and aromatic hydrocarbon group may be unsubstituted or substituted with one or more substituents ^X3 , and the above-mentioned alkyl group may be substituted with the above-mentioned cycloalkyl group or the above-mentioned cycloalkenyl group. One -CH ₂ - or two or more non-adjacent -CH ₂ - in the above-mentioned alkyl group may be independently substituted with -O-, -S-, -CO-, -COO-, -OCO-, -CO-S-, -S-CO-, -SO ₂ -, -O-CO-O-, -CO-NH-, -NH-CO-, -CH=CH-COO-, -CH=CH-OCO-, -COO-CH=CH-, -OCO-CH=CH-, -CH=CH-, -CF=CF- or -C≡C-; one -CH ₂ - or two or more non-adjacent -CH ₂ - in the above-mentioned cycloalkyl or cycloalkenyl group may be independently substituted with -O-, -CO-, -COO-, -OCO- or O-CO-O-. ^E11 , ^A11 , ^B12 , ^F12 and ^P12 are defined similarly to ^E1 , ^A1 , ^B1 , ^F1 and ^P1 in the above formula (1), and may be the same as or different from ^E1 , ^A1 , ^B1 , ^F1 and ^P1 , respectively. q represents an integer of 0 to 4, and when there are a plurality of ^E11 and/or ^A11 , they may be the same as or different from each other.

In order to obtain good birefringence and facilitate synthesis, ^T1 is preferably -O-, -S-, -N=CU ² - or -NU ² -. In order to easily improve wavelength dispersion and birefringence, -O-, -S- or -NU ² - is more preferably.

U ² is preferably an alkyl or alkenyl group having 1 to 20 carbon atoms, a _cycloalkyl group having 3 to 12 carbon atoms, or a cycloalkenyl group having 3 to 12 carbon atoms, which may be substituted by one or more of the above substituents ^X 3, and one -CH 2 - or two or more non-adjacent -CH ₂ - groups may be independently substituted by -O-, -CO-, -COO-, -OCO-, or -O-CO-O-, or the above alkyl or alkenyl group which may be substituted by the cycloalkyl group, cycloalkenyl group, or aryl group.

In terms of birefringence and solvent solubility, U ² is more preferably a linear alkyl group having 1 to 20 carbon atoms in which hydrogen atoms may be substituted with fluorine atoms and one -CH ₂ - or two or more non-adjacent -CH ₂ - may be independently substituted with -O-, -CO-, -COO- or -OCO-.

^U1 and ^U2 may also be bonded to form a ring. In this case, for example, a cyclic group represented ^{by -NU1U2} or ^a cyclic group represented by -N= ^CU1U2 can be cited.

In order to easily obtain the raw materials, have good solubility and show a high birefringence, ^Y3 and ^Y4 are preferably groups respectively selected from the following formulas (Y-1') to (Y-47').

From the viewpoint of making the orientation of the polymerizable liquid crystal compound (1) good, facilitating industrial production, and improving productivity, the molecular structure of the polymerizable liquid crystal compound (1) is preferably symmetrical. The group represented by formula (2-5) may specifically include the following groups. In the following (2-5a) to (2-5t), * represents a bonding part with ^D1 or ^D2 .

Among formulas (2-1) to (2-5), formula (2-1), formula (2-3), formula (2-4) and formula (2-5) are preferred, formula (2-1) and formula (2-5) are more preferred, and formula (2-1) is particularly preferred.

In the present invention, the polymerizable liquid crystal compound represented by formula (1) includes, for example, compounds described in Japanese Patent Application Publication No. 2019-003177 and Japanese Patent Application Publication No. 2019-073496.

The polymerizable liquid crystal compound (1-1) and the polymerizable liquid crystal compound (1-2) constituting the polymerizable liquid crystal composition of the present invention differ from each other only in the structure of the 1,4-cyclohexanediyl group represented by ^G1 and ^G2 in the structure represented by the above formula (1). Regarding the polymerizable liquid crystal compound (1-1), ^G1 and ^G2 in the formula (1) are both 1,4-trans-cyclohexanediyl groups, and regarding the polymerizable liquid crystal compound (1-2), based on the structure of the polymerizable liquid crystal compound (1-1), it differs from the polymerizable liquid crystal compound (1-1) only in that at least one of ^G1 and ^G2 is 1,4-cis-cyclohexanediyl groups.

In the present invention, the polymerizable liquid crystal compound (1-2) may be a polymerizable liquid crystal compound (1-2a) (hereinafter also referred to as “polymerizable liquid crystal compound (1-2a)”) in which either ^G1 or ^G2 in formula (1) is 1,4-trans-cyclohexanediyl and the other is 1,4-cis-cyclohexanediyl, or a polymerizable liquid crystal compound (1-2b) (hereinafter also referred to as “polymerizable liquid crystal compound (1-2b)”) in which both ^G1 and ^G2 in formula (1) are 1,4-cis-cyclohexanediyl. The polymerizable liquid crystal composition of the present invention may include only one of the polymerizable liquid crystal compound (1-2a) and the polymerizable liquid crystal compound (1-2b), or may include both.

The polymerizable liquid crystal composition of the present invention comprises a polymerizable liquid crystal composition (1-1) and a polymerizable liquid crystal compound (1-2) in an amount wherein the ratio of the peak area of the polymerizable liquid crystal compound (1-2) measured by liquid chromatography to the total peak area of the polymerizable liquid crystal compound (1-1) and the polymerizable liquid crystal compound (1-2) (hereinafter also referred to as the "area percentage value") is greater than 0.01% and less than 10%. Regarding the polymerizable liquid crystal compound represented by formula (1) having a so-called T-shaped structure in which constituent molecules are arranged in the direction of the long axis of the main chain of the compound and in the direction intersecting the long axis, when ^G1 and ^G2 in formula (1) are both 1,4-trans-cyclohexanediyl (i.e., polymerizable liquid crystal compound (1-1)), the molecular structure is generally stable and it is easy to align in a desired direction compared to the polymerizable liquid crystal compound (1-2) in which at least one of ^G1 and ^G2 in formula (1) is 1,4-cis-cyclohexanediyl, so that an optical film with fewer alignment defects can be manufactured. Therefore, from the viewpoint of alignment and optical properties, the polymerizable liquid crystal compound (1-1) is considered to be more advantageous as the polymerizable liquid crystal compound represented by formula (1). In the present invention, by setting the amount of the polymerizable liquid crystal compound (1-2) relative to the polymerizable liquid crystal compound (1-1) within a specific range, the solubility of the polymerizable liquid crystal compound (1-1) in the solvent can be sufficiently improved without affecting the alignment of the polymerizable liquid crystal compound (1-1).

If the area percentage value of the polymerizable liquid crystal compound (1-2) is less than the above lower limit, it is difficult to improve the solubility of the polymerizable liquid crystal compound (1-1) in the solvent. If the area percentage value of the polymerizable liquid crystal compound (1-2) is greater than the above lower limit, the solubility of the polymerizable liquid crystal compound (1-1) in the solvent tends to be sufficiently improved. In addition, if the area percentage value of the polymerizable liquid crystal compound (1-2) is less than the above upper limit, the liquid crystal alignment state can be kept good when an optical film such as a phase difference film is prepared from a polymerizable liquid crystal composition containing the polymerizable liquid crystal compound, thereby obtaining an optical film with excellent optical properties while suppressing alignment defects. In the present invention, the area percentage value of the polymerizable liquid crystal compound (1-2) is preferably less than 9%, further preferably less than 8%, particularly preferably less than 7%, and particularly preferably less than 6%. In the present invention, the area percentage value of the above-mentioned polymerizable liquid crystal compound (1-2) is preferably more than 0.1%, more preferably 0.5%, and further preferably more than 2.5%. On the other hand, in the present invention, even when a small amount of the polymerizable liquid crystal compound (1-2) is included, the effect of greatly improving the solubility of the polymerizable liquid crystal compound (1-1) in the solvent is also excellent. Therefore, in one form of the present invention, the area percentage value of the polymerizable liquid crystal compound (1-2) may not reach 1.0%, for example, less than 0.5% or less than 0.1%. In this case, it is also easy to fully obtain the above-mentioned advantageous effects of the present invention. Furthermore, when a plurality of polymerizable liquid crystal compounds equivalent to the polymerizable liquid crystal compound (1-1) and/or the polymerizable liquid crystal compound (1-2) are included, the area percentage value of the polymerizable liquid crystal compound (1-2) is calculated relative to the total peak area of all polymerizable liquid crystal compounds (1-2) and all polymerizable liquid crystal compounds (1-1). The area percentage value can be calculated based on the peak area measured by liquid chromatography, and in detail, it can be measured and calculated by the method described in the following examples.

The method for preparing the polymerizable liquid crystal compound represented by the formula (1) of the polymerizable liquid crystal compound (1-1) and the polymerizable liquid crystal compound (1-2) constituting the polymerizable liquid crystal composition of the present invention is not particularly limited, and the polymerizable liquid crystal compound can be prepared by converting the polymerizable liquid crystal compound (1-1) and the polymerizable liquid crystal compound (1-2) into a polymerizable liquid crystal compound according to the structure of the polymerizable liquid crystal compound. The compound can be produced by appropriately combining known organic synthesis reactions described in "Synthesis", "New Experimental Chemistry Lectures" and the like (for example, condensation reaction, esterification reaction, Williamson reaction, Ulmann reaction, Wittig reaction, Schiff base formation reaction, benzylation reaction, Sonogashira reaction, Suzuki-Miyaura reaction, Negishi reaction, Kumada reaction, Hirayama reaction, Buchwald-Hartwig reaction, Friedel-Craft reaction, Heck reaction, aldol reaction, etc.).

For example, in formula (1), ^D1 and ^D2 are *-O-CO- (* represents a bonding portion to Ar), ^G1 and ^G2 are 1,4-trans-cyclohexanediyl, and have a symmetrical structure centered on Ar (i.e., ^E1 and ^E2 , ^A1 and ^{A2 ,} B1 and ^B2 , ^F1 and ^F2 , ^P1 and ^P2 are the same), and the following formula (A-1) is given: The polymerizable liquid crystal compound (1-1) represented by formula (B): HO-Ar-OH (B) can be reacted with an alcohol compound (B) represented by formula (C): Furthermore, Ar, ^{E1, E2} , A1, ^A2 , ^B1 , B2, F1, F2, ^P1 and ^P2 in the above formula (A- ^{1 )} , formula (B) and formula (C) are the same as those defined in the above formula (1), and are determined corresponding to the structure of the polymerizable liquid crystal compound (1-1) ^{represented by} formula (A- ¹ ).

The alcohol compound (B) may be a compound having two hydroxyl groups bonded to the aromatic group Ar of the desired polymerizable liquid crystal compound (1-1), and the aromatic group Ar corresponds to the aromatic group Ar in formula (1). The aromatic group Ar is the same as that specified above, and examples thereof include compounds in which two * moieties are hydroxyl groups in the above formulas (2-1) to (2-5).

The carboxylic acid compound (C) may be any compound in which a carboxyl group is bonded to 1,4-trans-cyclohexanediyl group as ^G1 in the structure corresponding to P1- ^F1 - ^B1 - ^A1 - ^E1 - ^G1- in the formula ( ¹ ) of the desired polymerizable liquid crystal compound (1-1).

The polymerizable liquid crystal compound (1-2a) in which either ^G1 or ^G2 in formula (1) is 1,4-cis-cyclohexanediyl can be prepared, for example, by reacting the alcohol compound (B) with the carboxylic acid compound (C) to obtain the following formula (D): The compound represented by is prepared by reacting the compound with the following formula (C'): Furthermore, Ar, ^E1 , ^E2 , ^A1 , ^A2 , ^B1 , B2, ^F1 , ^F2 , ^P1 and ^P2 in the above formulas (C') and (D ⁾ are the same as those defined in the above formula (1), and are determined corresponding to the structure of the polymerizable liquid crystal compound (1-1) represented by formula (A-1).

In addition, the polymerizable liquid crystal compound (1-2b) in which ^G1 and ^G2 in formula (1) are both 1,4-cis-cyclohexanediyl can be produced, for example, by using a carboxylic acid compound (C') instead of the carboxylic acid compound (C) in the method exemplified as the method for producing the polymerizable liquid crystal compound (1-1).

The esterification reaction of the alcohol compound (B) and the carboxylic acid compound (C) and/or the carboxylic acid compound (C') is preferably carried out in the presence of a condensing agent. By carrying out the esterification reaction in the presence of a condensing agent, the esterification reaction can be carried out efficiently and rapidly.

Examples of the condensing agent include 1-cyclohexyl-3-(2-oxoethyl)carbodiimide methyl p-toluenesulfonate, dicyclohexylcarbodiimide, diisopropylcarbodiimide, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (water-soluble carbodiimide: commercially available as WSC), bis(2,6-diisopropyl)carbodiimide, Carbodiimide compounds such as bis(trimethylsilyl)carbodiimide, 2-methyl-6-nitrobenzoic anhydride, 2,2'-carbonylbis-1H-imidazole, 1,1'-oxalyldiimidazole, diphenylphosphatidyl azide, 1(4-nitrobenzenesulfonyl)-1H-1,2,4-triazole, 1H-benzotriazol-1-yl-oxytripyrrolidinophosphonium hexafluorophosphate, 1 H-benzotriazol-1-yl-oxytris(dimethylamino)phosphonium, N,N,N',N'-tetramethyl-O-(N-succinimidyl)uronium tetrafluoroborate, N-(1,2,2,2-tetrachloroethoxycarbonyloxy)succinimidyl, N-benzyloxycarbonylsuccinimidyl, O-(6-chlorobenzotriazol-1-yl)-N,N,N',N'-tetramethyluronium tetrafluoroborate, O-(6- chlorobenzotriazol-1-yl)-N,N,N',N'-tetramethyluronium, 2-bromo-1-ethylpyridinium tetrafluoroborate, 2-chloro-1,3-dimethylimidazolinium chloride, 2-chloro-1,3-dimethylimidazolinium hexafluorophosphate, 2-chloro-1-methylpyridinium iodide, 2-chloro-1-methylpyridinium p-toluenesulfonate, 2-fluoro-1-methylpyridinium p-toluenesulfonate and pentachlorophenyl trichloroacetate, etc.

The polymerizable liquid crystal compound (1-1) and the polymerizable liquid crystal compound (1-2) constituting the polymerizable liquid crystal composition of the present invention can be used as a liquid crystal mixture by preparing them separately and then mixing them. In addition, a liquid crystal mixture containing the polymerizable liquid crystal compound ( ^1-1 ) and the polymerizable liquid crystal compound (1-2a) and/or the polymerizable liquid crystal compound (1-2b) can also be prepared by a method including the step of reacting the reactive group ^R2 of the compound represented by the following formula (I), the reactive group ^R2 of the compound represented by the formula (II), and R1 of the compound represented by the formula (III). [In the formula, ^R1 and ^R2 independently represent reactive groups, and Ar, ^E1 , ^E2 , ^A1 , ^A2 , ^B1 , ^B2 , ^F1 , ^F2 , ^P1 and ^P2 have the same meanings as Ar, ^E1 , ^E2 , A1, ^A2 , ^B1 , ^B2 , ^F1 , ^F2 , ^P1 and ^P2 in formula ( ¹ )] The former method can easily control the contents of the polymerizable liquid crystal compound (1-1) and the polymerizable liquid crystal compound (1-2) in the polymerizable liquid crystal composition. The latter method has the advantages of simple synthesis and more efficient production of the polymerizable liquid crystal composition.

Ar, ^E1 , ^E2 , ^A1 , ^A2 , ^B1 , ^B2 , ^F1 , ^F2 , ^P1 and ^P2 in formula (I), formula (II) and formula (III) are determined according to the molecular structures corresponding to the desired polymerizable liquid crystal compound (1-1) and polymerizable liquid crystal compound (1-2).

^R1 in formula (III) and ^R2 in formula (I) and formula (II) can react with each other to form the structures represented by ^D1 and D2 in formula (1) representing polymerizable liquid crystal compound (1-1) and polymerizable liquid crystal compound (1-2). For example, as the reactive group represented by ^R1 and/or ^R2 , hydroxyl group, carboxyl group, amino group, etc. can be mentioned. The reactive groups represented by ^R1 and ^R2 can be selected according to the reaction used in the production of the polymerizable liquid crystal ^compound .

From the viewpoints of the ease of reaction, the operability of the material, and the ease of obtaining, for example, an alcohol compound in which R ¹ is a hydroxyl group in formula (III) as a compound represented by formula (III), and a carboxylic acid compound in which R ² is a carboxyl group in formula (I) and formula (II) as a compound represented by formula (I) and a compound represented by formula (II) are respectively carried out to carry out an esterification reaction, thereby producing a polymerizable liquid crystal compound (liquid crystal mixture) constituting the polymerizable liquid crystal composition of the present invention. The esterification reaction can be carried out in the same manner as the esterification reaction that can be used to produce the polymerizable liquid crystal compound represented by formula (I), for example, the above-mentioned method, or the method and conditions described in Japanese Patent Laid-Open No. 2019-003177, etc.

By adjusting the amount of the compound represented by formula (I) and the compound represented by formula (II) used in the preparation, the content ratio of the polymerizable liquid crystal compound (1-1), the polymerizable liquid crystal compound (1-2a) and the polymerizable liquid crystal compound (1-2b) in the obtained liquid crystal mixture can be controlled. By using a plurality of carboxylic acid compounds in the method of reacting R ¹ with R ² , a plurality of compounds can be synthesized simultaneously.

The polymerizable liquid crystal composition of the present invention may also contain polymerizable liquid crystal compounds other than polymerizable liquid crystal compound (1-1) and polymerizable liquid crystal compound (1-2) as long as it does not affect the effect of the present invention. Examples of other polymerizable liquid crystal compounds other than polymerizable liquid crystal compound (1-1) and polymerizable liquid crystal compound (1-2) include polymerizable liquid crystal compounds that do not have the molecular structure represented by formula (1), polymerizable liquid crystal compounds that generally show positive wavelength dispersion when aligned and polymerized, and compounds having polymerizable groups in the compounds described in "3.8.6 Network (Completely Cross-linked Type)" and "6.5.1 Liquid Crystal Material b. Polymerizable Nematic Liquid Crystal Material" of Liquid Crystal Handbook (Edited by Liquid Crystal Handbook Editorial Committee, published by Maruzen Co., Ltd. on October 30, 2001).

When the polymerizable liquid crystal composition of the present invention contains polymerizable liquid crystal compounds other than the polymerizable liquid crystal compound (1-1) and the polymerizable liquid crystal compound (1-2), from the viewpoint of obtaining a liquid crystal cured film having a higher degree of alignment order, the ratio of the polymerizable liquid crystal compound (1) to the total mass of all polymerizable liquid crystal compounds contained in the polymerizable liquid crystal composition is preferably 51 mass % or more, more preferably 70 mass % or more, further preferably 90 mass % or more, and may also be 100 mass %.

When more than two polymerizable liquid crystal compounds (1-1) are included, it is sufficient to include a polymerizable liquid crystal compound (1-2) corresponding to at least one of the polymerizable liquid crystal compounds (1-1). The content of the polymerizable liquid crystal compound (1-1) (the corresponding polymerizable liquid crystal compound (1-2)) and the corresponding polymerizable liquid crystal compound (1-2) relative to the total mass of all polymerizable liquid crystal compounds is preferably 60 mass % or more, more preferably 70 mass % or more, and even more preferably 80 mass % or more.

The content of the polymerizable liquid crystal compound in the polymerizable liquid crystal composition (the total amount of all polymerizable liquid crystal compounds) is, for example, 70 to 99.5 parts by mass, preferably 80 to 99 parts by mass, more preferably 85 to 98 parts by mass, and further preferably 90 to 95 parts by mass relative to 100 parts by mass of the solid components of the polymerizable liquid crystal composition. If the content of the polymerizable liquid crystal compound is within the above range, it is more advantageous from the perspective of the orientation of the obtained liquid crystal cured film. Furthermore, in this specification, the solid components of the polymerizable liquid crystal composition refer to all components after removing volatile components such as organic solvents from the polymerizable liquid crystal mixture.

The polymerizable liquid crystal composition of the present invention may further contain additives such as a photopolymerization initiator, an organic solvent, a polymerization inhibitor, a photosensitizer, and a leveling agent in addition to the polymerizable liquid crystal compound (1-1) and the polymerizable liquid crystal compound (1-2). These components may be used alone or in combination of two or more.

The polymerizable liquid crystal composition of the present invention preferably contains a polymerization initiator. The polymerization initiator is a compound that can generate reactive species by the contribution of heat or light and start the polymerization reaction of the polymerizable liquid crystal. As reactive species, free radicals, cations or anions can be cited as active species. Among them, from the perspective of easy control of the reaction, a photopolymerization initiator that generates free radicals by light irradiation is preferred.

Examples of the photopolymerization initiator include benzoin compounds, benzophenone compounds, benzyl ketal compounds, α-hydroxy ketone compounds, α-amino ketone compounds, tris(iodine) compounds, iodonium salts, and coronium salts. Specifically, there can be mentioned: Irgacure (registered trademark) 907, Irgacure 184, Irgacure 651, Irgacure 819, Irgacure 250, Irgacure 369, Irgacure 379, Irgacure 127, Irgacure 2959, Irgacure 754, Irgacure 379EG (all manufactured by BASF Japan Co., Ltd.), Seikuol BZ, Seikuol Z, Seikuol BEE (all manufactured by Seiko Chemical Co., Ltd.), Kayacure BP100 (manufactured by Nippon Kayaku Co., Ltd.), Kayacure UVI-6992 (manufactured by Dow), Adeka Optomer SP-152, Adeka Optomer SP-170, Adeka Optomer N-1717, Adeka Optomer N-1919, Adeka Arkles NCI-831, Adeka Arkles NCI-930 (all manufactured by ADEKA Co., Ltd.), TAZ-A, TAZ-PP (all manufactured by Nihon SiberHegner Co., Ltd.) and TAZ-104 (manufactured by Sanwa Chemical Co., Ltd.). In the present invention, the polymerizable liquid crystal composition preferably contains at least one photopolymerization initiator, and may also contain two or more photopolymerization initiators.

The photopolymerization initiator can fully utilize the energy emitted from the light source and has excellent productivity. Therefore, the maximum absorption wavelength is preferably 300 nm to 400 nm, more preferably 300 nm to 380 nm. Among them, α-acetophenone-based polymerization initiators and oxime-based photopolymerization initiators are preferred.

Examples of the α-acetophenone-based polymerization initiator include 2-methyl-2-oxo-1-(4-methylthiophenyl)propane-1-one, 2-dimethylamino-1-(4-oxo-1-phenyl)-2-benzylbutane-1-one, and 2-dimethylamino-1-(4-oxo-1-phenyl)-2-(4-methylphenylmethyl)butane-1-one. More preferred examples include 2-methyl-2-oxo-1-(4-methylthiophenyl)propane-1-one and 2-dimethylamino-1-(4-oxo-1-phenyl)-2-benzylbutane-1-one. Examples of commercially available α-acetophenone compounds include Irgacure 369, 379EG, and 907 (all manufactured by BASF Japan Co., Ltd.) and Seikuol BEE (manufactured by Seiko Chemical Industries, Ltd.).

Oxime-based photopolymerization initiators generate methyl radicals by irradiation with light. The polymerizable liquid crystal compound is suitably polymerized in the deep part of the formed liquid crystal cured film by means of the methyl radicals. In addition, from the viewpoint of more efficiently carrying out the polymerization reaction in the deep part of the formed liquid crystal cured film, it is preferable to use a photopolymerization initiator that can efficiently utilize ultraviolet rays with a wavelength of more than 350 nm. As photopolymerization initiators that can efficiently utilize ultraviolet rays with a wavelength of more than 350 nm, trioxime compounds and oxime ester-type carbazole compounds are preferred, and from the viewpoint of sensitivity, oxime ester-type carbazole compounds are more preferred. Examples of the oxime ester type carbazole compound include 1,2-octanedione, 1-[4-(phenylthio)-2-(O-benzoyl oxime)], ethyl ketone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3-yl]-1-(O-acetyl oxime), etc. Examples of commercially available oxime ester type carbazole compounds include Irgacure OXE-01, Irgacure OXE-02, Irgacure OXE-03 (all manufactured by BASF Japan Co., Ltd.), Adeka Optomer N-1919, Adeka Arkles NCI-831 (all manufactured by ADEKA Co., Ltd.), etc.

The amount of the photopolymerization initiator added is usually 0.1 to 30 parts by mass, preferably 0.5 to 100 parts by mass, more preferably 1 to 20 parts by mass, and more preferably 15 parts by mass or less, relative to 100 parts by mass of the polymerizable liquid crystal compound. If it is within the above range, the reaction of the polymerizable group will proceed sufficiently and it is difficult to disrupt the alignment of the polymerizable liquid crystal compound.

In the present invention, the polymerizable liquid crystal composition is usually coated on a substrate or the like in a state of being dissolved in a solvent, and therefore preferably contains a solvent. As the solvent, it is preferred that a solvent that can dissolve the polymerizable liquid crystal compound (1-1) and the polymerizable liquid crystal compound (1-2) constituting the polymerizable liquid crystal composition be used, and it is preferred that the solvent be inert to the polymerization reaction of the polymerizable liquid crystal compound. Examples of the solvent include alcohol solvents such as water, methanol, ethanol, ethylene glycol, isopropanol, propylene glycol, ethylene glycol methyl ether, ethylene glycol butyl ether, 1-methoxy-2-propanol, 2-butoxyethanol, and propylene glycol monomethyl ether; ester solvents such as ethyl acetate, butyl acetate, ethylene glycol methyl ether acetate, γ-butyrolactone, propylene glycol methyl ether acetate, and ethyl lactate; acetone, methyl ethyl ketone, cyclopentanone, cyclohexanone, 2-heptanone, and methyl Ketone solvents such as 1,2-dimethyl-2-butyl-ketone, 1,2-dimethyl-2-pyrrolidone (NMP), 1,3-dimethyl-2-imidazolidinone, etc.; aliphatic hydrocarbon solvents such as pentane, hexane and heptane; aliphatic hydrocarbon solvents such as ethylcyclohexane; aromatic hydrocarbon solvents such as toluene and xylene; nitrile solvents such as acetonitrile; ether solvents such as tetrahydrofuran and dimethoxyethane; chlorine-containing solvents such as chloroform and chlorobenzene; amide solvents such as dimethylacetamide, dimethylformamide, N-methyl-2-pyrrolidone (NMP), 1,3-dimethyl-2-imidazolidinone, etc. These solvents may be used alone or in combination of two or more. Among them, organic solvents are preferred, and alcohol solvents, ester solvents, ketone solvents, chlorine-containing solvents, amide solvents, and aromatic hydrocarbon solvents are more preferred.

The content of the solvent in the polymerizable liquid crystal composition is preferably 50 to 98 parts by mass, and more preferably 70 to 95 parts by mass, relative to 100 parts by mass of the polymerizable liquid crystal composition. Therefore, in 100 parts by mass of the polymerizable liquid crystal composition, the solid component is preferably 2 to 50 parts by mass, and more preferably 5 to 30 parts by mass. If the solid component is less than 50 parts by mass, the viscosity of the polymerizable liquid crystal composition tends to be lower, and the thickness of the film becomes roughly uniform, and it is not easy to produce uneven trends. The above-mentioned solid component can be appropriately determined by considering the thickness of the liquid crystal cured film to be manufactured.

By preparing a polymerization inhibitor, the polymerization reaction of the polymerizable liquid crystal compound can be controlled. Examples of the polymerization inhibitor include: hydroquinone and hydroquinones having substituents such as alkyl ethers; butyl o-o ...

Furthermore, by using a sensitizer, the photopolymerization initiator can be highly sensitive. Examples of the photosensitizer include thiophene, 9-oxothiophene, Anthracene and anthracene with alkyl ether and other substituents; phenanthrene; rubrene. As photosensitizers, for example, phenanthene, 9-oxythiophene Ketones; anthracene and anthracene with alkyl ether and other substituents; phenanthrene; rubrene. The content of the photosensitizer is usually 0.01 to 10 parts by weight, preferably 0.05 to 5 parts by weight, and further preferably 0.1 to 3 parts by weight, relative to 100 parts by weight of the polymerizable liquid crystal compound.

Furthermore, the polymerizable liquid crystal composition of the present invention may also include a leveling agent. The leveling agent is an additive that has the function of adjusting the fluidity of the polymerizable liquid crystal composition and making the film obtained by coating the polymerizable liquid crystal composition flatter. Examples include: polysilicone-based, polyacrylate-based, and perfluoroalkyl-based leveling agents. Specifically, examples include: DC3PA, SH7PA, DC11PA, SH28PA, SH29PA, SH30PA, ST80PA, ST86PA, SH8400, SH8700, FZ2123 (all manufactured by Toray Dow Corning Co., Ltd.), KP321, KP323, KP324, KP326, KP340, KP341, X22-161A, KF6001 (all manufactured by Shin-Etsu Chemical Co., Ltd.), TSF400, TSF401, TSF410, TSF4300, TSF4440, TSF4445, TSF-4446, TSF4452, TSF4460 (all manufactured by Maitu Advanced Materials Japan Co., Ltd.), fluorinert (registered trademark) FC-72, fluorinert FC-40, fluorinert FC-43, fluorinert FC-3283 (all manufactured by Sumitomo 3M Co., Ltd.), Megafac (registered trademark) R-08, Megafac R-30, Megafac R-90, Megafac F-410, Megafac F-411, Megafac F-443, Megafac F-445, Megafac F-470, Megafac F-477, Megafac F-479, Megafac F-482, Megafac F-483 (all manufactured by DIC Co., Ltd.), Eftop (trade name) EF301, Eftop EF303, Eftop EF351, Eftop EF352 (all manufactured by Mitsubishi Materials Corporation), Surflon (registered trademark) S-381, Surflon S-382, Surflon S-383, Surflon S-393, Surflon SC-101, Surflon SC-105, KH-40, SA-100 (all manufactured by AGC Seimei Chemical Co., Ltd.), trade name E1830, trade name E5844 (manufactured by Daikin Fine Chemicals Laboratories Co., Ltd.), BM-1000, BM-1100, BYK-352, BYK-353 and BYK-361N (all trade names: manufactured by BM Chemie Co., Ltd.), etc. Among them, polyacrylate-based leveling agents and perfluoroalkyl-based leveling agents are preferred.

The content of the leveling agent in the polymerizable liquid crystal composition is preferably 0.01 to 5 parts by mass, and more preferably 0.05 to 3 parts by mass, relative to 100 parts by mass of the polymerizable liquid crystal compound. If the content of the leveling agent is within the above range, it is easy to align the polymerizable liquid crystal compound, and the obtained liquid crystal cured film tends to become smooth, so it is preferred. The polymerizable liquid crystal composition may also have two or more leveling agents.

The polymerizable liquid crystal composition of the present invention can be prepared by the following method: adding a solvent, a photopolymerization initiator, a polymerization inhibitor, a photosensitizer or a leveling agent and other additives to the polymerizable liquid crystal compound (1-1) and the polymerizable liquid crystal compound (1-2) as needed, and stirring and mixing the mixture at a specified temperature.

<Phase difference film> Regarding the polymerizable liquid crystal composition of the present invention, the polymerizable liquid crystal compound has a high solubility in the solvent, and therefore has an excellent effect of suppressing the generation of alignment defects caused by the precipitation and precipitation of undissolved polymerizable liquid crystal compounds and polymerizable liquid crystal compounds in storage. Therefore, by using the polymerizable liquid crystal composition of the present invention, it is possible to form a film without reducing the optical properties that the polymerizable liquid crystal compound can originally exhibit, and a liquid crystal cured film with excellent optical properties can be obtained. Therefore, the present invention also relates to a phase difference film, which includes a liquid crystal cured film, which is a cured product (liquid crystal cured film) of the polymerizable liquid crystal composition of the present invention, and is cured in the state of the alignment of the polymerizable liquid crystal compound in the polymerizable liquid crystal composition. The phase difference film including the above-mentioned liquid crystal cured film can fully demonstrate the optical properties that the polymerizable liquid crystal compound used can originally exert, and can become a phase difference film with higher optical performance.

The liquid crystal cured film constituting the phase difference film of the present invention may also include a homopolymer of the polymerizable liquid crystal compound (1-1) and a homopolymer of the polymerizable liquid crystal compound (1-2) in an aligned state, and may also include a copolymer of a mixture of the polymerizable liquid crystal compound (1-1) and the polymerizable liquid crystal compound (1-2) in an aligned state. Since the polymerization reaction is easier and a uniform liquid crystal cured film is more easily obtained, the liquid crystal cured film constituting the phase difference film of the present invention is preferably a copolymer of a mixture of the polymerizable liquid crystal compound (1-1) and the polymerizable liquid crystal compound (1-2) in an aligned state.

In one form of the present invention, the phase difference film of the present invention includes a liquid crystal cured film as a cured product of the polymerizable liquid crystal composition of the present invention, and the liquid crystal cured film preferably has the optical properties represented by the following formula (i): 0.75≦Re(450)/Re(550)＜1.0    (i) [In formula (i), Re(λ) represents the in-plane phase difference value of the liquid crystal cured film at a wavelength of λ nm]. When the liquid crystal cured film satisfies formula (i), it exhibits the so-called reverse wavelength dispersion, that is, the in-plane phase difference value of the liquid crystal cured film at a short wavelength is smaller than the in-plane phase difference value at a long wavelength. In order to improve the reverse wavelength dispersion and further improve the optical properties of the phase difference film, Re(450)/Re(550) is preferably greater than 0.76, and more preferably greater than 0.78, and more preferably less than 0.92, and more preferably less than 0.90, particularly preferably less than 0.87, particularly preferably less than 0.86, and particularly preferably less than 0.85.

In one form of the present invention, the phase difference film of the present invention is preferably a liquid crystal cured film having optical properties represented by the following formula (ii): 1.00≦Re(650)/Re(550)    (ii) [In formula (ii), Re(λ) represents the in-plane phase difference value of the phase difference film at a wavelength of λ nm]. From the perspective of the optical properties of the phase difference film, Re(650)/Re(550) is preferably greater than 1.01, and further preferably greater than 1.02.

Furthermore, in one form of the present invention, the phase difference film of the present invention preferably comprises a liquid crystal cured film having optical properties represented by the following formula (iii): 100 nm≦Re(550)≦180 nm    (iii) [In formula (iii), Re(λ) represents the in-plane phase difference value of the phase difference film at a wavelength of λ nm]. The liquid crystal cured film satisfying the above formula (iii) functions as a λ/4 plate, and the elliptical polarizing plate having a phase difference film including the liquid crystal cured film is excellent in improving the front reflection hue (suppressing coloring) when applied to an optical display or the like. The more preferable range of the in-plane phase difference value is 120 nm≦Re(550)≦170 nm, and the further preferable range is 130 nm≦Re(550)≦150 nm.

The above-mentioned in-plane phase difference value can be adjusted according to the thickness d of the liquid crystal cured film. The in-plane phase difference value is determined by the above-mentioned formula Re(λ)＝(nx(λ)－ny(λ))×d. Therefore, in order to obtain the required in-plane phase difference value (Re(λ): in-plane phase difference value of the liquid crystal cured film at wavelength λ(nm)), it is only necessary to adjust the three-dimensional refractive index and the film thickness d. Furthermore, in the above-mentioned formula, d represents the thickness of the liquid crystal cured film as the object, nx represents the principal refractive index at a wavelength λ nm in the direction parallel to the plane of the liquid crystal cured film in the refractive index ellipsoid formed by the liquid crystal cured film, and ny represents the refractive index at a wavelength λ nm in the direction parallel to the plane of the liquid crystal cured film and orthogonal to the above-mentioned direction of nx in the refractive index ellipsoid formed by the liquid crystal cured film.

The phase difference film of the present invention can be manufactured, for example, by a method comprising the following steps: Forming a coating film of the polymerizable liquid crystal composition of the present invention, drying the coating film, and aligning the polymerizable liquid crystal compound in the polymerizable liquid crystal composition; and While maintaining the alignment state, polymerizing the polymerizable liquid crystal compound by light irradiation to form a liquid crystal cured film.

The coating film of the polymerizable liquid crystal composition can be formed by coating the polymerizable liquid crystal composition on a substrate or on the alignment film described below. As the substrate, for example, a glass substrate and a film substrate can be cited. From the viewpoint of processability, a resin film substrate is preferred. As the resin constituting the film substrate, for example, polyolefins such as polyethylene, polypropylene, and norolefin polymers; cycloolefin resins; polyvinyl alcohol; polyethylene terephthalate; polymethacrylate; polyacrylate; cellulose esters such as triacetyl cellulose, diacetyl cellulose, and cellulose acetate propionate; polyethylene naphthalate; polycarbonate; polysulfone; polyethersulfone; polyetherketone; plastics such as polyphenylene sulfide and polyphenylene ether can be cited. The substrate can be made by forming a film of such a resin by a known method such as solvent casting or melt extrusion. The surface of the substrate may also have a protective layer formed of an acrylic resin, a methacrylic resin, an epoxy resin, an oxycyclobutane resin, a polyurethane resin, a melamine resin, etc., and may also be subjected to a surface treatment such as a release treatment such as a silicone treatment, a corona treatment, or a plasma treatment.

Commercially available products may also be used as the substrate. Examples of commercially available cellulose ester substrates include cellulose ester substrates manufactured by FUJI FILM Co., Ltd. such as Fujitac Film, and cellulose ester substrates manufactured by Konica Minolta Opto Co., Ltd. such as "KC8UX2M", "KC8UY", and "KC4UY". Examples of commercially available cycloolefin resins include: cycloolefin resins manufactured by Ticona Corporation (sole proprietorship) such as "Topas (registered trademark)", cycloolefin resins manufactured by JSR Corporation such as "ARTON (registered trademark)", cycloolefin resins manufactured by Zeon Co., Ltd. such as "ZEONOR (registered trademark)" and "ZEONEX (registered trademark)", and cycloolefin resins manufactured by Mitsui Chemicals Co., Ltd. such as "APEL (registered trademark). Commercially available cycloolefin resin substrates may also be used. Examples of commercially available cycloolefin resin substrates include: "S-SINA (registered trademark)" and "SCA40 (registered trademark)" manufactured by Sekisui Chemical Industries, Ltd.; "ZEONOR Film (registered trademark)" manufactured by Optes Co., Ltd.; and "ARTON Film (registered trademark)" manufactured by JSR Co., Ltd.

From the viewpoints of thinning of the retardation film, ease of substrate peeling, and substrate handling, the thickness of the substrate is generally 5 to 300 μm, preferably 10 to 150 μm.

Examples of methods for coating the polymerizable liquid crystal composition on a substrate include: coating methods such as spin coating, extrusion coating, gravure coating, die coating, rod coating, and application coating; and printing methods such as flexographic printing.

Then, the solvent is removed by drying, etc., thereby forming a dry coating. Examples of drying methods include natural drying, ventilation drying, heating drying, and reduced pressure drying. At this time, by heating the coating obtained from the polymerizable liquid crystal composition, the solvent can be dried and removed from the coating, and the polymerizable liquid crystal compound can be aligned in a desired direction (for example, horizontal or vertical direction) relative to the plane of the coating. The heating temperature of the coating can be appropriately determined in consideration of the materials of the polymerizable liquid crystal compound used and the substrate forming the coating, but in order to make the polymerizable liquid crystal compound phase transition to the liquid crystal phase state, it is usually necessary to be a temperature above the liquid crystal phase transition temperature. In order to remove the solvent contained in the polymerizable liquid crystal composition and make the polymerizable liquid crystal compound into the desired alignment state, for example, it can be heated to a temperature above the liquid crystal phase transition temperature (smectic phase transition temperature or nematic phase transition temperature) of the polymerizable liquid crystal compound contained in the above-mentioned polymerizable liquid crystal composition. Furthermore, the liquid crystal phase transition temperature can be measured, for example, using a polarizing microscope with a temperature adjustment stage, a differential scanning calorimeter (DSC), a thermogravimetric differential thermal analyzer (TG-DTA), etc. The above-mentioned phase transition temperature of the polymerizable liquid crystal composition of the present invention containing at least two polymerizable liquid crystal compounds refers to the temperature measured using a mixture of polymerizable liquid crystal compounds formed by mixing all the polymerizable liquid crystal compounds constituting the polymerizable liquid crystal composition in the same ratio as the composition of the polymerizable liquid crystal composition.

The polymerizable liquid crystal composition of the present invention comprises at least two polymerizable liquid crystal compounds (1-1) and a polymerizable liquid crystal compound (1-2), and can generally undergo liquid crystal phase transition at a temperature lower than the temperature at which the individual polymerizable liquid crystal compound (1-1) or the polymerizable liquid crystal compound (1-2) transitions to the liquid crystal phase. Therefore, in the manufacture of a phase difference film using the polymerizable liquid crystal composition of the present invention, excessive consumption of thermal energy can be suppressed, and production efficiency can be improved. In addition, by performing liquid crystal phase transition by heating at a relatively low temperature, there is also an advantage of increasing the options for supporting substrates for coating the polymerizable liquid crystal composition.

The heating time can be appropriately determined according to the heating temperature, the type of polymerizable liquid crystal compound used, the type of solvent, the boiling point and amount of the solvent, etc., but is usually 15 seconds to 10 minutes, preferably 0.5 to 5 minutes.

Regarding the removal of the solvent from the coating, it can be carried out simultaneously with the heating to a temperature above the liquid crystal phase transition temperature of the polymerizable liquid crystal compound, or it can be carried out separately, but from the perspective of improving productivity, it is preferably carried out simultaneously. It is also possible to set a pre-drying step before heating to a temperature above the liquid crystal phase transition temperature of the polymerizable liquid crystal compound, which step is used to appropriately remove the solvent in the coating under the condition that the polymerizable liquid crystal compound contained in the coating obtained from the polymerizable liquid crystal composition is not polymerized. Examples of drying methods in the pre-drying step include natural drying, ventilation drying, heating drying, and reduced pressure drying. The drying temperature (heating temperature) in the drying step can be appropriately determined according to the type of polymerizable liquid crystal compound used, the type of solvent, and the boiling point and amount of the solvent.

Then, in the obtained dry coating, the polymerizable liquid crystal compound is polymerized by light irradiation in the alignment state of the polymerizable liquid crystal compound, forming a liquid crystal cured film as a polymer of the polymerizable liquid crystal compound in the desired alignment state. The polymerizable liquid crystal composition of the present invention can suppress damage to the polymerizable liquid crystal compound and can be highly polymerized by irradiation with high-intensity ultraviolet light, so photopolymerization is generally used as a polymerization method. In photopolymerization, the light irradiated to the dry coating is appropriately selected according to the type of polymerization initiator contained in the dry coating, the type of polymerizable liquid crystal compound and its amount. As a specific example, one or more lights selected from the group consisting of visible light, ultraviolet light, infrared light, X-rays, α rays, β rays and γ rays and active electron beams can be cited. Among them, ultraviolet light is preferred in terms of easy control of the progress of the polymerization reaction and the ability to be used as a photopolymerization device by a wide range of users in this field. It is preferred to select the types of polymerizable liquid crystal compounds and polymerization initiators contained in the polymerizable liquid crystal composition in a manner that allows photopolymerization by ultraviolet light. In addition, during polymerization, the dried coating is cooled by an appropriate cooling method and irradiated with light, thereby controlling the polymerization temperature. If the polymerization of the polymerizable liquid crystal compound is carried out at a lower temperature by adopting such a cooling method, a liquid crystal cured film can be properly formed even if a substrate with relatively low heat resistance is used. In addition, the polymerization temperature is increased within a range that does not cause adverse conditions caused by heat during light irradiation (such as deformation of the substrate caused by heat), thereby promoting the polymerization reaction. During photopolymerization, a patterned cured film can also be obtained by performing masking and development.

Examples of the light source of the active energy line include low-pressure mercury lamps, medium-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, xenon lamps, halogen lamps, carbon arc lamps, tungsten filament lamps, gallium lamps, excimer lasers, LED (Light Emitting Diode) light sources emitting light in the wavelength range of 380 to 440 nm, chemical lamps, black light lamps, microwave-excited mercury lamps, and metal halogen lamps.

The intensity of ultraviolet irradiation is usually 10 to 3,000 mW/cm ² . The intensity of ultraviolet irradiation is preferably an intensity in the wavelength region effective for activation of photopolymerization initiators. The irradiation time is usually 0.1 second to 10 minutes, preferably 0.1 second to 5 minutes, more preferably 0.1 second to 3 minutes, and further preferably 0.1 second to 1 minute. If the ultraviolet irradiation intensity is used once or multiple times, the cumulative light amount is 10 to 3,000 mJ/cm ² , preferably 50 to 2,000 mJ/cm ² , and more preferably 100 to 1,000 mJ/cm ² .

The thickness of the liquid crystal cured film can be appropriately selected according to the optical display used, etc. It is preferably 0.2 to 3 μm, and more preferably 0.2 to 2 μm.

The coating of the polymerizable liquid crystal composition can also be formed on the alignment film. The alignment film is a film that has an alignment restriction force that allows the polymerizable liquid crystal compound liquid crystal to align in a desired direction. For example, there is a horizontal alignment film for an alignment film that has an alignment restriction force that allows the polymerizable liquid crystal compound to align in a horizontal direction, and there is a vertical alignment film for an alignment film that has an alignment restriction force that allows the polymerizable liquid crystal compound to align in a vertical direction. The alignment restriction force can be arbitrarily adjusted according to the type of alignment film, surface state, and friction conditions, etc. When the alignment film is formed of a photo-alignable polymer, it can be arbitrarily adjusted according to polarized light irradiation conditions, etc.

As an alignment film, it is preferred that the film has solvent resistance such that the polymerizable liquid crystal composition is not dissolved by coating, etc., and has heat resistance in the heat treatment for removing the solvent and aligning the polymerizable liquid crystal compound described below. As an alignment film, there can be cited: an alignment film comprising an alignment polymer, a photo-alignment film, a groove alignment film having a concave-convex pattern and a plurality of grooves on the surface, and an extension film extending along the alignment direction. From the perspective of the accuracy and quality of the alignment angle, a photo-alignment film is preferred.

As the alignment polymer, for example, there can be cited: polyamides and gelatins having amide bonds in the molecule, polyimides having imide bonds in the molecule and polyamides as hydrolyzates thereof, polyvinyl alcohol, alkyl-modified polyvinyl alcohol, polyacrylamide, polyazole, polyethyleneimine, polystyrene, polyvinyl pyrrolidone, polyacrylic acid, and polyacrylates. Among them, polyvinyl alcohol is preferred. The alignment polymer can be used alone or in combination of two or more.

The alignment film including the alignment polymer is usually obtained by applying a composition in which the alignment polymer is dissolved in a solvent (hereinafter sometimes referred to as "alignment polymer composition") to a substrate and removing the solvent; or applying the alignment polymer composition to a substrate, removing the solvent and rubbing (rubbing method). As the solvent, the same solvent as exemplified as the solvent that can be used in the polymerizable liquid crystal composition can be cited.

The concentration of the alignment polymer in the alignment polymer composition can be within the range that the alignment polymer material can be completely dissolved in the solvent, but is preferably 0.1 to 20% in terms of solid content relative to the solution, and more preferably about 0.1 to 10%.

As the alignment polymer composition, a commercially available alignment film material may be used as it is. Examples of commercially available alignment film materials include Sunever (registered trademark, manufactured by Nissan Chemical Industries, Ltd.) and Optomer (registered trademark, manufactured by JSR Corporation).

As a method for applying the aligning polymer composition on the substrate, the same methods as exemplified as the method for applying the polymerizable liquid crystal composition on the substrate can be cited.

Examples of methods for removing the solvent contained in the alignment polymer composition include natural drying, ventilation drying, heat drying, and reduced pressure drying.

In order to impart an alignment restricting force to the alignment film, a rubbing treatment (rubbing method) may be performed as needed. As a method of imparting an alignment restricting force by the rubbing method, the following method may be cited as an example: a rotating rubbing roller wrapped with a rubbing cloth is brought into contact with an alignment polymer film formed on the surface of a substrate, the alignment polymer film being formed by coating an alignment polymer composition on the substrate and annealing it. If masking is performed during the rubbing treatment, multiple regions (patterns) with different alignment directions may also be formed on the alignment film.

The photo-alignment film is usually obtained by applying a composition comprising a polymer or monomer having a photoreactive group and a solvent (hereinafter also referred to as a "photo-alignment film forming composition") to a substrate, removing the solvent, and then irradiating the substrate with polarized light (preferably polarized UV light). The photo-alignment film is also advantageous in that the direction of the alignment restraining force can be arbitrarily controlled by selecting the polarization direction of the polarized light irradiated.

Photoreactive groups refer to groups that generate liquid crystal alignment ability by light irradiation. Specifically, groups that participate in the photoreactions that are the origin of the liquid crystal alignment ability, such as molecular alignment induction or isomerization reaction, dimerization reaction, photocrosslinking reaction or photodecomposition reaction generated by light irradiation, can be cited. Among them, groups that participate in dimerization reaction or photocrosslinking reaction are preferred in terms of excellent alignment. As photoreactive groups, groups having unsaturated bonds, especially double bonds, are preferred, and groups having at least one selected from the group consisting of carbon-carbon double bonds (C=C bonds), carbon-nitrogen double bonds (C=N bonds), nitrogen-nitrogen double bonds (N=N bonds) and carbon-oxygen double bonds (C=O bonds) are particularly preferred.

Examples of photoreactive groups having a C=C bond include vinyl, polyene, stilbene, styrylpyridyl, styrylpyridinium, chalcone, and cinnamyl groups. Examples of photoreactive groups having a C=N bond include groups having structures such as aromatic Schiff bases and aromatic hydrazones. Examples of photoreactive groups having an N=N bond include azophenyl, azonaphthyl, aromatic heterocyclic azo, bisazo, formazan, and groups having an oxyazobenzene structure. Examples of photoreactive groups having a C=O bond include benzophenone, coumarin, anthraquinone, and maleimide groups. These groups may have a substituent such as an alkyl group, an alkoxy group, an aryl group, an allyloxy group, a cyano group, an alkoxycarbonyl group, a hydroxyl group, a sulfonic acid group, or a halogenated alkyl group.

Among them, the photoreactive groups that participate in the photodimerization reaction are preferred. In terms of the relatively small amount of polarized light irradiation required for photo-alignment and the ease of obtaining a photo-alignment film with excellent thermal stability and temporal stability, cinnamoyl and chalcone groups are preferred. As a polymer having a photoreactive group, a cinnamoyl group having a cinnamic acid structure at the end of the polymer side chain is particularly preferred.

By coating the photo-alignment film-forming composition on a substrate, a photo-alignment inducing layer can be formed on the substrate. The solvent contained in the composition may be the same as the solvent exemplified as the solvent that can be used in the polymerizable liquid crystal composition, and may be appropriately selected according to the solubility of the polymer or monomer having a photoreactive group.

The content of the polymer or monomer having a photoreactive group in the photo-alignment film-forming composition can be appropriately adjusted according to the type of the polymer or monomer and the thickness of the target photo-alignment film, preferably at least 0.2 mass % relative to the mass of the photo-alignment film-forming composition, and more preferably in the range of 0.3-10 mass %. The photo-alignment film-forming composition may also contain a polymer material such as polyvinyl alcohol or polyimide or a photosensitizer within a range that does not significantly damage the properties of the photo-alignment film.

As a method for applying the photo-alignment film-forming composition on a substrate, the same method as the method for applying the aligning polymer composition on a substrate can be cited. As a method for removing the solvent from the applied photo-alignment film-forming composition, for example, natural drying, ventilation drying, heat drying, and reduced pressure drying can be cited.

Regarding the irradiation of polarized light, the following two forms are possible, namely, the form of directly irradiating the polarized UV light obtained by removing the solvent from the photo-alignment film-forming composition applied on the substrate, and the form of irradiating the polarized light from the substrate side so that the polarized light is transmitted. In addition, the polarized light is preferably substantially parallel light. The wavelength of the polarized light irradiated can be a wavelength region in which the photoreactive group of the polymer or monomer having a photoreactive group can absorb light energy. Specifically, UV (ultraviolet light) with a wavelength range of 250 to 400 nm is particularly preferred. As the light source used for the polarized light irradiation, there can be cited: xenon lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, metal halogen lamps, KrF, ArF and other ultraviolet lasers, etc., and high-pressure mercury lamps, ultra-high-pressure mercury lamps and metal halogen lamps are more preferred. Among them, high-pressure mercury lamps, ultra-high-pressure mercury lamps and metal halogen lamps are more preferred because of the high intensity of ultraviolet light with a wavelength of 313 nm. Polarized UV can be irradiated by passing the light from the above light sources through an appropriate polarizing element. As the polarizing element, a polarizing filter, a polarizing prism such as Glen-Thompson or Glen-Taylor, and a wire-grid type polarizing element can be used.

Furthermore, if shielding is performed during rubbing or polarized light irradiation, multiple regions (patterns) with different liquid crystal alignment directions can also be formed.

A groove-aligned film is a film with a concave-convex pattern or multiple grooves on its surface. When a polymerizable liquid crystal compound is coated on a film with multiple linear grooves arranged at equal intervals, the liquid crystal molecules are aligned along the direction of the grooves.

As methods for obtaining a groove alignment film, the following methods can be cited as examples: a method of exposing the surface of a photosensitive polyimide film through an exposure mask having slits in the shape of a pattern, and then performing development and rinsing to form a concave-convex pattern; a method of forming a pre-cured UV-curable resin layer on a plate-shaped master having grooves on its surface, and then transferring the formed resin layer to a substrate and curing it; and a method of pressing a roll-shaped master having a plurality of grooves against a pre-cured UV-curable resin film formed on a substrate to form concave-convex patterns, and then curing it.

The thickness of the alignment film (including the alignment film of the alignment polymer or the photo-alignment film) is usually in the range of 10 to 10000 nm, preferably in the range of 10 to 1000 nm, more preferably in the range of 10 to 500 nm or less, further preferably in the range of 10 to 300 nm, and particularly preferably in the range of 50 to 250 nm.

<Elliptical polarizing plate> The present invention includes an elliptical polarizing plate including the phase difference film of the present invention. The elliptical polarizing plate of the present invention includes the phase difference film of the present invention and a polarizing film. The polarizing film is a film having a polarizing function, and examples thereof include a stretched film adsorbed with a dye having absorption anisotropy, and a film coated with a dye having absorption anisotropy as a polarizing element. As a dye having absorption anisotropy, for example, a dichroic dye can be cited.

A film including a stretched film adsorbed with a dye having absorption anisotropy as a polarizing element is usually produced by sandwiching a transparent protective film via an adhesive on at least one side of the polarizing element. The polarizing element is produced by the following steps: a step of uniaxially stretching a polyvinyl alcohol resin film, a step of dyeing the polyvinyl alcohol resin film with a dichroic dye to adsorb the dichroic dye, a step of treating the polyvinyl alcohol resin film adsorbed with the dichroic dye with a boric acid aqueous solution, and a step of washing with water after the treatment with the boric acid aqueous solution.

Polyvinyl alcohol resins can be obtained by saponifying polyvinyl acetate resins. As polyvinyl acetate resins, in addition to polyvinyl acetate which is a homopolymer of vinyl acetate, copolymers of vinyl acetate and other monomers copolymerizable therewith can be used. Examples of other monomers copolymerizable with vinyl acetate include unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, and acrylamides having an ammonium group.

The saponification degree of polyvinyl alcohol resin is usually about 85-100 mol%, preferably 98 mol% or more. Polyvinyl alcohol resin can also be modified, for example, polyvinyl formal or polyvinyl acetaldehyde modified with aldehydes can also be used. The polymerization degree of polyvinyl alcohol resin is usually about 1,000-10,000, preferably in the range of 1,500-5,000.

The polyvinyl alcohol resin is used as a film for a polarizing film. The method for forming the polyvinyl alcohol resin is not particularly limited, and the film can be formed by a known method. The film thickness of the polyvinyl alcohol film can be set to about 10 to 150 μm, for example.

The uniaxial stretching of the polyvinyl alcohol resin film can be performed before, at the same time as, or after dyeing with a dichroic dye. When the uniaxial stretching is performed after dyeing, the uniaxial stretching can be performed before the boric acid treatment or during the boric acid treatment. Furthermore, the uniaxial stretching can be performed in these multiple stages. During the uniaxial stretching, the uniaxial stretching can be performed between rollers with different peripheral speeds, or a hot roller can be used for uniaxial stretching. Furthermore, the uniaxial stretching can be dry stretching performed in the atmosphere, or wet stretching performed in a state where the polyvinyl alcohol resin film is swollen using a solvent. The stretching ratio is usually about 3 to 8 times.

The polyvinyl alcohol-based resin film is dyed with a dichroic dye by, for example, immersing the polyvinyl alcohol-based resin film in an aqueous solution containing the dichroic dye.

As the dichroic pigment, specifically, iodine or a dichroic organic dye is used. Examples of the dichroic organic dye include dichroic direct dyes containing bis-azo compounds such as C.I. DIRECT RED 39, and dichroic direct dyes containing trisazo, tetrakis-azo, and the like. The polyvinyl alcohol-based resin film is preferably immersed in water before dyeing.

When iodine is used as a dichroic pigment, a method of dyeing is usually adopted in which a polyvinyl alcohol-based resin film is immersed in an aqueous solution containing iodine and potassium iodide. The content of iodine in the aqueous solution is usually about 0.01 to 1 mass part relative to 100 mass parts of water. In addition, the content of potassium iodide is usually about 0.5 to 20 mass parts relative to 100 mass parts of water. The temperature of the aqueous solution used for dyeing is usually about 20 to 40°C. In addition, the immersion time in the aqueous solution (dyeing time) is usually about 20 to 1,800 seconds.

On the other hand, when a dichroic organic dye is used as a dichroic pigment, a method of dyeing is usually adopted in which a polyvinyl alcohol-based resin film is immersed in an aqueous solution containing a water-soluble dichroic dye. The content of the dichroic organic dye in the aqueous solution is usually about 1×10 ^-4 to 10 parts by mass, preferably 1×10 ^{-3 to 1 part by mass, and further preferably 1×10 -3 to} 1×10 ^-2 parts by mass relative to 100 parts by mass of water. The aqueous solution may also contain inorganic salts such as sodium sulfate as a dyeing auxiliary. The temperature of the dichroic dye aqueous solution used for dyeing is usually about 20 to 80°C. In addition, the immersion time (dyeing time) in the aqueous solution is usually about 10 to 1,800 seconds.

The boric acid treatment after dyeing with a dichroic dye can usually be performed by immersing the dyed polyvinyl alcohol-based resin film in an aqueous boric acid solution. The content of boric acid in the aqueous boric acid solution is usually about 2 to 15 parts by mass, preferably 5 to 12 parts by mass, relative to 100 parts by mass of water. When iodine is used as the dichroic dye, the aqueous boric acid solution preferably contains potassium iodide, and the content of potassium iodide at this time is usually about 0.1 to 15 parts by mass, preferably 5 to 12 parts by mass, relative to 100 parts by mass of water. The immersion time in the aqueous boric acid solution is usually about 60 to 1,200 seconds, preferably 150 to 600 seconds, and further preferably 200 to 400 seconds. The temperature of the boric acid treatment is usually above 50°C, preferably 50-85°C, and further preferably 60-80°C.

The polyvinyl alcohol resin film treated with boric acid is usually washed with water. The washing treatment can be performed, for example, by immersing the polyvinyl alcohol resin film treated with boric acid in water. The temperature of the water in the washing treatment is usually about 5 to 40°C. The immersion time is usually about 1 to 120 seconds.

After washing, drying treatment is performed to obtain a polarizing element. Drying treatment can be performed, for example, using a hot air dryer or a far infrared heater. The temperature of the drying treatment is usually around 30 to 100°C, preferably 50 to 80°C. The time of the drying treatment is usually around 60 to 600 seconds, preferably 120 to 600 seconds. Through the drying treatment, the moisture content of the polarizing element is reduced to a practical level. The moisture content is usually around 5 to 20 mass%, preferably 8 to 15 mass%. If the moisture content is within the above range, it is easy to obtain a polarizing element with appropriate flexibility and excellent thermal stability.

The thickness of the polarizing element obtained by uniaxially stretching the polyvinyl alcohol resin film, dyeing with a dichroic pigment, treating with boric acid, washing with water and drying in this way is preferably 5 to 40 μm.

As the film coated with the dye having absorption anisotropy, there can be exemplified a film obtained by coating a composition containing a dichroic dye having liquid crystal properties, or a composition containing a dichroic dye and a polymerizable liquid crystal compound. The film preferably has a protective film on one or both sides thereof. As the protective film, there can be exemplified the same resin film as exemplified as the substrate that can be used in the production of the above-mentioned liquid crystal cured film.

The film coated with the dye having absorption anisotropy is preferably thin, but from the viewpoint of strength and processability, the thickness of the film is usually 20 μm or less, preferably 5 μm or less, and more preferably 0.5 to 3 μm.

Specific examples of the film coated with the dye having absorption anisotropy include films described in Japanese Patent Application Laid-Open No. 2013-33249 and the like.

A transparent protective film is laminated on at least one side of the polarizing element obtained in this way via an adhesive to obtain a polarizing film. As the transparent protective film, the same transparent film as the resin film exemplified as the substrate that can be used in the production of the liquid crystal cured film constituting the phase difference film can be suitably used.

The elliptical polarizing plate of the present invention includes the phase difference film and the polarizing film of the present invention. For example, the elliptical polarizing plate of the present invention can be obtained by laminating the phase difference film and the polarizing film of the present invention via a bonding agent layer or an adhesive layer.

In one aspect of the present invention, when the phase difference film of the present invention including the liquid crystal cured film and the polarizing film are laminated, it is preferred that the phase difference film is laminated so that the angle between the retardation axis (optical axis) of the liquid crystal cured film constituting the phase difference film and the absorption axis of the polarizing film becomes 45±5°.

The elliptical polarizing plate of the present invention may have the structure of the conventional elliptical polarizing plate, polarizing film and phase difference film. Such structure may include, for example, an adhesive layer (sheet) for attaching the elliptical polarizing plate to a display element constituting an optical display, a protective film for protecting the surface of the polarizing film and phase difference film from damage and contamination, and the like.

The elliptical polarizing plate of the present invention can be used in various display devices, especially optical displays. A display device refers to a device having a display element, including a light-emitting element or a light-emitting device as a light source. Examples of display devices include liquid crystal display devices, organic electroluminescent (EL) display devices, inorganic electroluminescent (EL) display devices, flexible image display devices, touch panel display devices, electron emission display devices (e.g., field emission display devices (FED), surface field emission display devices (SED)), electronic paper (display devices using electronic ink or electrophoretic elements), plasma display devices, projection display devices (e.g., grating valve imaging system (GLV) display devices, display devices with digital micromirror devices (DMD)), and piezoelectric ceramic displays. Liquid crystal display devices include any one of transmissive liquid crystal display devices, semi-transmissive liquid crystal display devices, reflective liquid crystal display devices, direct-view liquid crystal display devices, and projection liquid crystal display devices. The display devices may be display devices for displaying two-dimensional images or three-dimensional display devices for displaying three-dimensional images. In particular, the elliptical polarizer of the present invention is suitable for use in organic electroluminescent (EL) display devices and inorganic electroluminescent (EL) display devices. The display devices (optical displays) can exhibit good image display characteristics by using the elliptical polarizer of the present invention having excellent optical characteristics.

The flexible image display device having the elliptical polarizing plate of the present invention preferably further has a window and a touch panel touch sensor. The flexible image display device, for example, includes a multilayer body for a flexible image display device and an organic EL display panel, and is configured in a manner such that the multilayer body for a flexible image display device is arranged on the viewing side relative to the organic EL display panel and can be bent. As a multilayer body for a flexible image display device, in addition to the elliptical polarizing plate of the present invention, it can also include a window, a touch panel touch sensor, etc. The stacking order is arbitrary, but preferably, the stacking is in the order of window, elliptical polarizing plate, touch panel touch sensor or in the order of window, touch panel touch sensor, elliptical polarizing plate from the visual side.

When there is an elliptical polarizing plate on the visual side of the touch panel touch sensor, the pattern of the touch panel touch sensor is not easily visible, and the visibility of the displayed image is improved, which is preferred. Each component can be laminated using adhesives, adhesives, etc. In addition, the laminated body for the flexible image display device can have a light-shielding pattern formed on at least one side of any layer of the above-mentioned window, elliptical polarizing plate, and touch panel touch sensor.

The window is arranged on the viewing side of the flexible image display device to protect other components from external impact or environmental changes such as temperature and humidity. Previously, glass was used as such a protective layer, but the window of the flexible image display device is not rigid and hard like glass, but has the property of flexibility. The above-mentioned window includes a flexible transparent substrate and may also include a hard coating layer on at least one side.

The transparent substrate preferably has a visible light transmittance of 70% or more, and more preferably has a visible light transmittance of 80% or more. As the transparent substrate, any transparent polymer film can be used. Among them, polyamide film, polyamide imide film or polyimide film, polyester film, olefin film, acrylic film, cellulose film with excellent transparency and heat resistance are preferred. It is also preferred to disperse inorganic particles such as silicon dioxide, organic microparticles, colloidal particles, etc. in the polymer film.

The thickness of the transparent substrate is preferably 5 to 200 μm, more preferably 20 to 100 μm.

A hard coating layer may be provided on at least one side of the transparent substrate constituting the window. The thickness of the hard coating layer is not particularly limited, and may be, for example, 2 to 100 μm. If the thickness of the hard coating layer is within the above range, sufficient impact resistance, scratch resistance, and bending resistance can be easily ensured.

The hard coating layer can be formed by curing a hard coating layer-forming composition containing a reactive material that forms a cross-linked structure by irradiating active energy rays or thermal energy, but preferably, the hard coating layer is formed by curing with active energy rays. Active energy rays are defined as energy rays that can decompose compounds that generate active species to generate active species. Examples of active energy rays include visible light, ultraviolet rays, infrared rays, X-rays, α rays, β rays, γ rays, and electron beams, and ultraviolet rays are particularly preferred. The hard coating layer-forming composition usually contains at least one compound of a free radical polymerizable compound and a cationic polymerizable compound, and a polymerization initiator. There are no particular limitations on the free radical polymerizable compound, the cationic polymerizable compound, and the polymerization initiator, and examples thereof include those previously known. The hard coating composition may further include one or more selected from the group consisting of solvents and additives. As long as the solvent can dissolve or disperse the polymerizable compound and the polymerization initiator, any solvent known as a composition for forming a hard coating in the field of optical films may be used without limitation. Examples of the additive include inorganic particles, leveling agents, stabilizers, surfactants, antistatic agents, lubricants, antifouling agents, and the like.

The touch panel touch sensor is used as an output mechanism. As a touch panel touch sensor, various types such as a resistive film method, a surface acoustic wave method, an infrared method, an electromagnetic induction method, and an electrostatic capacitance method are disclosed, and any method may be used. Among them, the electrostatic capacitance method is preferred. The electrostatic capacitance method touch panel touch sensor is divided into an active area and an inactive area located outside the active area. The active area is an area corresponding to the area (display part) where the screen is displayed in the display panel, and is an area that senses the user's touch, and the inactive area is an area corresponding to the area (non-display part) where the screen is not displayed in the display device. The touch panel touch sensor may include: a substrate having a flexible characteristic; a sensing pattern formed in an active area of the substrate; and sensing lines formed in an inactive area of the substrate for connecting to an external driving circuit via the sensing pattern and a pad.

There is no particular restriction on the substrate, sensing pattern and sensing lines having flexible characteristics, and materials applicable in the technical field can be selected respectively.

As a substrate having a flexible property, for example, a substrate comprising the same material as the transparent substrate of the above-mentioned window can be used. Regarding the substrate of the touch panel touch sensor, in terms of suppressing cracking of the touch panel touch sensor, it is preferred that the toughness is 2,000 MPa% or more, and more preferably the toughness is 2,000 MPa% to 30,000 MPa%. Here, toughness is defined as the area below the curve up to the rupture point in the stress (MPa)-strain (%) curve obtained by the tensile test of the polymer material.

Each layer (window, elliptical polarizing plate, touch panel touch sensor) forming the above-mentioned flexible image display device and the film components (polarizing film, phase difference film, etc.) constituting each layer can be formed by an adhesive. As the adhesive, water-based adhesives, organic solvent-based adhesives, solvent-free adhesives, solid adhesives, solvent sublimation adhesives, moisture-curing adhesives, heat-curing adhesives, anaerobic curing adhesives, active energy ray-curing adhesives, curing agent mixed adhesives, hot melt adhesives, pressure-sensitive adhesives (adhesives), rewetting adhesives, etc., which are commonly used, can be used. Among them, the preferred ones are water-based solvent sublimation adhesives, active energy ray curing adhesives, and adhesives. The thickness of the adhesive layer can be appropriately adjusted according to the required bonding force, but is usually 0.01 μm to 500 μm, preferably 0.1 μm to 300 μm. When there are multiple adhesive layers in the laminated body of the above-mentioned flexible image display device, the type and thickness of the adhesive constituting each adhesive layer can be the same or different. [Implementation Example]

Hereinafter, the present invention will be described in more detail by way of examples. Furthermore, unless otherwise specified, "%" and "parts" in the examples refer to mass % and mass parts, respectively.

1. Preparation of polymerizable liquid crystal compounds and liquid crystal mixtures Production Example 1: Production of polymerizable liquid crystal compounds represented by formula (A-1) The polymerizable liquid crystal compound represented by the following formula (A-1) (hereinafter referred to as "polymerizable liquid crystal compound (A-1)") was synthesized according to the following process.

A 100 mL four-necked flask equipped with a Dai's condenser and a thermometer was placed in a nitrogen atmosphere, 11.02 g of the compound (E-1) synthesized in the reference patent document (Japanese Patent Laid-Open No. 2010-31223), 4.00 g of the compound (D-1) synthesized in the reference patent document (Japanese Patent Laid-Open No. 2011-207765), 0.02 g of DMAP (manufactured by Wako Jun Chemical Industries, Ltd.), 0.20 g of BHT (manufactured by Wako Jun Chemical Industries, Ltd.), and 58 g of chloroform (manufactured by Kanto Chemical Industry Co., Ltd.) were added and mixed, and then 4.05 g of IPC (manufactured by Wako Jun Chemical Industries, Ltd.) was added using a dropping funnel, and the mixture was reacted at 0°C overnight. After the reaction is completed, the insoluble components are removed by filtration. The obtained chloroform solution is added dropwise to acetonitrile (produced by Wako Pure Chemical Industries, Ltd.) having a weight three times the weight of the chloroform contained in the solution to precipitate a solid. Then, the precipitated solid is taken out by filtration, washed three times with 20 g of acetonitrile, and dried under reduced pressure at 30°C to obtain 11.43 g of a polymerizable liquid crystal compound (A-1). The yield of the polymerizable liquid crystal compound (A-1) is 80% based on compound (D-1).

Production Example 2: Production of Liquid Crystal Mixture (A') A liquid crystal mixture (hereinafter also referred to as "liquid crystal mixture (A')") containing polymerizable liquid crystal compounds represented by the following formulae (A-1) to (A-3) was synthesized according to the following process. Referring to the patent document (Japanese Patent Laid-Open No. 2010-31223), trans-1,4-cyclohexanedicarboxylic acid was replaced with cis-1,4-cyclohexanedicarboxylic acid to synthesize 27.02 g of a mixture represented by compound (E-2). Compound (E-2) and compound (E-1) were mixed at a ratio of 10/90, and compound (E-1) of Preparation Example 1 was replaced with the above mixture of compound (E-2) and compound (E-1) to obtain 10.57 g of a liquid crystal mixture (A'). The obtained liquid crystal mixture (A') was analyzed by HPLC (high performance liquid chromatography). As a result, the liquid crystal mixture contained the above-mentioned compound (A-1), compound (A-2) and compound (A-3), and the total peak area of the above-mentioned compound (A-2) and compound (A-3) was 3.00% relative to the total peak area of compound (A-1), compound (A-2) and compound (A-3) (100%).

[HLPC measurement] HPLC measurement can be performed under any conditions as long as the peak from the polymerizable liquid crystal compound can be separated. The following shows the HPLC measurement conditions used in the analysis of the embodiments and comparative examples of the present invention. (Measurement conditions) Measurement device: HPLC LC-10AT (manufactured by Shimadzu Corporation) Column: L-Column ODS (inner diameter 3.0 mm, length 150 mm, particle size 3 μm) Temperature: 40°C Mobile phase A: 0.1% (v/v)-TFA/water Mobile phase B: 0.1% (v/v)-TFA/acetonitrile Gradient: 0 min 70%-B 30 min 100%-B 60 min 100%-B 60.01 min 70%-B 75 min 70%-B Flow rate: 0.5 mL/min Injection volume: 5 μL Detection wavelength: 254 nm

Production Example 3: Production of a polymerizable liquid crystal compound represented by formula (B-1) A polymerizable liquid crystal compound represented by the following formula (B-1) (hereinafter referred to as "polymerizable liquid crystal compound (B-1)") was synthesized according to the following process.

Except for changing the amount of compound (D-2) to 4.22 g, the same method as described in Preparation Example 1 was used to obtain 11.75 g of polymerizable liquid crystal compound (B-1). The yield of polymerizable liquid crystal compound (B-1) was 81% based on compound (D-2).

Production Example 4: Production of Liquid Crystal Mixture (B') A liquid crystal mixture (hereinafter also referred to as "liquid crystal mixture (B')") containing polymerizable liquid crystal compounds represented by the following formulae (B-1) to (B-3) was synthesized according to the following process.

Except for changing to 4.22 g of compound (D-2), all the reactions were carried out in the same manner as described in Preparation Example 2 to obtain 10.88 g of a liquid crystal mixture (B'). The obtained liquid crystal mixture (B') was analyzed under the above-mentioned HPLC measurement conditions. As a result, the liquid crystal mixture contained the above-mentioned compound (B-1), compound (B-2) and compound (B-3), and the total peak area of the above-mentioned compound (B-2) and compound (B-3) was 5.23% relative to 100% of the total peak area of compound (B-1), compound (B-2) and compound (B-3).

Preparation Example 5: Preparation of Liquid Crystal Mixture (C') Except that the mixing ratio of compound (E-2) and compound (E-1) used in Preparation Example 4 was changed to 20/80, all the reactions were carried out in the same manner as described in Preparation Example 4 to obtain 10.44 g of liquid crystal mixture (C'). The obtained liquid crystal mixture (C') was analyzed under the above-mentioned HPLC measurement conditions. As a result, the liquid crystal mixture contained the above-mentioned compound (B-1), compound (B-2) and compound (B-3), and the total peak area of the above-mentioned compound (B-2) and compound (B-3) was 12.3% relative to the total peak area of compound (B-1), compound (B-2) and compound (B-3) (100%). Furthermore, in the above-mentioned production examples 1 to 5, compound (A-1) and compound (B-1) are respectively equivalent to the polymerizable liquid crystal compound (1-1) of the present invention, compound (A-2) and compound (B-2) are respectively equivalent to the polymerizable liquid crystal compound (1-2a) of the present invention, and compound (A-3) and compound (B-3) are respectively equivalent to the polymerizable liquid crystal compound (1-2b) of the present invention.

2. Polymerizable liquid crystal compounds/mixtures of Examples and Comparative Examples (1) Example 1: Preparation of liquid crystal mixture (1) Under the above-mentioned HPLC measurement conditions, the liquid crystal mixture (A') obtained in the above-mentioned Preparation Example 2 was mixed with the polymerizable liquid crystal compound (A-1) obtained in the above-mentioned Preparation Example 1 so that the peak area of compound (A-2) and compound (A-3) was 0.1% relative to the total peak area of compound (A-1), compound (A-2) and compound (A-3) 100%, thereby obtaining a liquid crystal mixture (1).

(2) Example 2: The liquid crystal mixture (A') obtained in the above-mentioned Preparation Example 2 is set as liquid crystal mixture (2).

(3) Example 3: Preparation of liquid crystal mixture (4) Under the above HPLC measurement conditions, the liquid crystal mixture (B') obtained in Preparation Example 4 was mixed with the polymerizable liquid crystal compound (B-1) obtained in Preparation Example 3 to obtain a liquid crystal mixture (3) in such a manner that the peak area of compound (B-2) and compound (B-3) was 0.4% relative to the total peak area of compound (B-1), compound (B-2) and compound (B-3) (100%).

(4) Example 4: The liquid crystal mixture (B') obtained in the above-mentioned Preparation Example 4 is set as liquid crystal mixture (4).

(5) Comparative Example 1: The polymerizable liquid crystal compound (A-1) obtained in Production Example 1 was used as the liquid crystal compound (1).

(6) Comparative Example 2: The polymerizable liquid crystal compound (B-1) obtained in Production Example 3 was used as the liquid crystal compound (2).

(7) Comparative Example 3: The liquid crystal mixture (C') obtained in Preparation Example 5 is used as liquid crystal mixture (5).

3. Solubility evaluation N-methylpyrrolidone (NMP) and a stirrer were placed in a bottle tube and stirred with a magnetic stirrer (HS-30DN, AS ONE). The liquid crystal mixtures (1) to (5) and liquid crystal compounds (1) and (2) prepared in the above-mentioned Examples 1 to 4 and Comparative Examples 1 to 3 were added respectively until no dissolution was visually confirmed. When no dissolution was confirmed, the solubility of each liquid crystal mixture and polymerizable liquid crystal compound in NMP was calculated by weight percentage concentration according to (weight of each liquid crystal mixture and polymerizable liquid crystal compound)/(weight of each liquid crystal mixture and polymerizable liquid crystal compound + weight of NMP). The results are shown in Table 2.

4. Evaluation of alignment defects (1) Preparation of optical film (retardation film) An optical film (retardation film) was prepared according to the following steps. (i) Preparation of a composition for forming an optical alignment film The following components were mixed and the obtained mixture was stirred at 80° C. for 1 hour to obtain a composition for forming an optical alignment film. A photo-alignment material represented by the following formula (5 parts) (number average molecular weight of about 28,000): Solvent (95 parts): Cyclopentanone

(ii) Preparation of polymerizable liquid crystal composition A cycloolefin polymer film (COP) (ZF-14, manufactured by Zeon Co., Ltd.) was treated once using a corona treatment device (AGF-B10, manufactured by Kasuga Electric Co., Ltd.) at an output of 0.3 kW and a treatment speed of 3 m/min. The photo-alignment film-forming composition was applied to the surface subjected to the corona treatment using a rod coater, dried at 80°C for 1 minute, and exposed to polarized UV light using a polarized UV irradiation device (SPOT CURE SP-7; manufactured by Ushio Electric Co., Ltd.) at a cumulative light dose of 100 mJ/ ^cm2 . The film thickness of the obtained photo-alignment film was measured using a laser microscope (LEXT, manufactured by Olympus Co., Ltd.) and the result was 100 nm. Then, the liquid crystal mixture (1) prepared in the above-mentioned Example 1 was added to the bottle tube, and a photopolymerization initiator, a leveling agent, a polymerization inhibitor and a solvent were added according to the composition listed in Table 1, and the mixture was stirred at 80° C. for 30 minutes using a rotating rack to obtain a polymerizable liquid crystal composition. Furthermore, the amount of the solvent was set so that the mass % of the liquid crystal mixture relative to the total amount of the polymerizable liquid crystal composition (solution) was 13%.

[Table 1] Liquid crystal mixture/liquid crystal compound Types of polymerizable liquid crystal compounds (1-1) Addition amount relative to 100 parts by mass of liquid crystal mixture/liquid crystal compound (parts by mass) Photopolymerization initiator Leveling agent Polymerization inhibitor Embodiment 1 Liquid crystal mixture (1) (A-1) 6 0.1 0.2 Embodiment 2 Liquid crystal mixture (2) (A-1) 6 0.1 0.2 Embodiment 3 Liquid crystal mixture (3) (B-1) 6 0.1 0.2 Embodiment 4 Liquid crystal mixture (4) (B-1) 6 0.1 0.2 Comparison Example 1 Liquid crystal compounds (1) (A-1) 6 0.1 0.2 Comparison Example 2 Liquid crystal compounds (2) (B-1) 6 0.1 0.2 Comparison Example 3 Liquid crystal mixture (5) (B-1) 6 0.1 0.2

Polymerization initiator: 2-benzyl-2-dimethylamino-1-(4-oxo-1,1-diphenyl)butane-1-one (Irgacure 369; manufactured by BASF Japan) Leveler: Polyacrylate compound (BYK-361N; manufactured by BYK-Chemie Japan) Polymerization inhibitor: BHT (manufactured by Wako Junyaku Industries) Solvent: N-methylpyrrolidone (NMP; manufactured by Kanto Chemical Co., Ltd.)

(iii) Preparation of Optical Film The obtained polymerizable liquid crystal composition was coated on the alignment film using a rod coater, dried at 120°C for 1 minute, and then irradiated with ultraviolet light (under nitrogen atmosphere, wavelength: 365 nm, cumulative light intensity at wavelength 365 nm: 1000 mJ/ ^cm2 ) using a high-pressure mercury lamp (uniQureVB-15201BY-A, manufactured by Niuwei Electric Co., Ltd.) to prepare an optical film. In addition, the liquid crystal mixtures (2) to (5), liquid crystal compounds (1) and (2) prepared in Examples 2 to 5 and Comparative Examples 1 to 3 were used instead of the above-mentioned liquid crystal mixture (1), and a photopolymerization initiator, a leveling agent, a polymerization inhibitor and a solvent were added according to the composition described in Table 1. Otherwise, a polymerizable liquid crystal composition and an optical film were prepared in the same manner as above.

(2) Evaluation of alignment defects The optical film was cut into 10 cm square pieces and the number of alignment defects on the screen was visually confirmed using a polarizing microscope (LEXT, manufactured by Olympus Corporation). The evaluation was performed according to the following evaluation criteria. The results are shown in Table 1. (Evaluation criteria for alignment defects) 1: Alignment defects are present on the entire surface (>100) 2: 11 to 100 3: 1 to 10 4: No defects

[Table 2] Liquid crystal mixture/liquid crystal compound Types of polymerizable liquid crystal compounds (1-1) Area percentage value of polymerizable liquid crystal compound (1-2) (%) Alignment defect assessment Solubility in NMP Embodiment 1 Liquid crystal mixture (1) (A-1) 0.1 4 4.2 Embodiment 2 Liquid crystal mixture (2) (A-1) 3 4 6.6 Embodiment 3 Liquid crystal mixture (3) (B-1) 0.4 4 6.1 Embodiment 4 Liquid crystal mixture (4) (B-1) 5.23 4 8.4 Comparison Example 1 Liquid crystal compounds (1) (A-1) 0 4 3.0 Comparison Example 2 Liquid crystal compounds (2) (B-1) 0 4 5.8 Comparison Example 3 Liquid crystal mixture (3) (B-1) 12.3 2 8.8

As shown in Table 1, it can be confirmed that the polymerizable liquid crystal composition (Examples 1 to 4) according to the present invention can suppress alignment defects and improve the solubility of the polymerizable liquid crystal compound (1-1) in the solvent by including a specific amount of the polymerizable liquid crystal compound (1-2) relative to the polymerizable liquid crystal compound (1-1).

Claims (11)

A polymerizable liquid crystal composition comprises at least two polymerizable liquid crystal compounds represented by formula (1) having the same molecular weight but different molecular structures, wherein P1- ^F1 - ^B1 - ^A1 - ^E1 - ^G1 - ^{D1 -} Ar- ^D2 -G2- ^E2 - ^A2 - ^B2 - ^F2 - ^P2 (1) [In formula (1), Ar represents a divalent aromatic hydrocarbon group or a divalent aromatic heterocyclic group which may have a substituent, and ^D1 , D2, ^E1 , ^E2 , B1 and ^B2 each independently represent ^-CR11R12- , -CH2- ^CH2- , -CR11R12-, -CH2-CH2-, -CR11R12-, -CH2-CH2-, -CR11R12-, -CH2- ^CH2- , -CR11R12-, -CH2-CH2-, -CR11R12-, -CH2-CH2-, -CR11R12-, -CH2-CH2-, -CR11R12-, -CH2-CH2-, -CR11R12-, ^{-CH2 -} CH2-, -CR11R12-, _-CH2 - _CH2- -, -O-, -S-, -CO-O-, -O-CO-, -O-CO-O-, -C(=S)-O-, -OC(=S)-, -OC(=S)-O-, -CO-NR ¹¹ -, -NR ¹¹ -CO-, -O-CH ₂ -, -CH ₂ -O-, -S-CH ₂ -, -CH ₂ -S- or a single bond; R ¹¹ and R ¹² each independently represent a hydrogen atom, a fluorine atom or an alkyl group having 1 to 4 carbon atoms; G ¹ and G ² each represent a 1,4-cyclohexanediyl group; A ¹ and A R ¹³ represents an alkyl group having 1 to 4 carbon atoms, and the hydrogen atom contained in the alkyl group may be substituted by a fluorine atom. F ¹ and F ² each independently represent an alkanediyl group having 1 to 12 carbon atoms, and the hydrogen atom contained in the alkanediyl group may be substituted by -OR ¹⁴ or a halogen atom. R ¹⁴ represents an alkyl group having ¹ to 4 carbon atoms, and the hydrogen atom contained in the alkyl group may be substituted by a fluorine atom. The -CH ² - contained in the alkanediyl group may be substituted by ^-O- or -CO-. P ₁ and P ² each independently represent ^a hydrogen atom or a polymerizable group (wherein P At least one of ^G1 and ^G2 is a polymerizable group)], as the above-mentioned polymerizable liquid crystal compound, it includes: a polymerizable liquid crystal compound (1-1) in which ^G1 and ^G2 in formula (1) are respectively 1,4-trans-cyclohexanediyl, and a polymerizable liquid crystal compound (1-2) whose molecular structure is different from that of the above-mentioned polymerizable liquid crystal compound (1-1) only when at least one of ^G1 and ^G2 in formula (1) is 1,4-cis-cyclohexanediyl; the ratio of the peak area of the polymerizable liquid crystal compound (1-2) measured by liquid chromatography to the total peak area of the polymerizable liquid crystal compound (1-1) and the polymerizable liquid crystal compound (1-2) is 0.01% or more and 10% or less; and the polymerizable liquid crystal compound (1-2) includes ^G1 and G2 in formula (1) ² is a polymerizable liquid crystal compound (1-2a) in which either one of them is 1,4-cis-cyclohexanediyl, and a polymerizable liquid crystal compound (1-2b) in which both ^G1 and ^G2 in formula (1) are 1,4-cis-cyclohexanediyl. The polymerizable liquid crystal composition of claim 1, wherein Ar in formula (1) is a group represented by any one of formulas (2-1) to (2-5),

[In the formula, * represents a bonding portion with D ¹ or D ² ; Q ¹ represents -S-, -O- or -NR ¹⁵ -, R ¹⁵ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms which may have a substituent, Q ² represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms which may have a substituent; W ¹ and W ² each independently represent -O-, -S-, -CO- or -NR ¹⁵ -, R ¹⁵ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms which may have a substituent; Y ^{1 represents an alkyl group having 1 to 6 carbon atoms, an aromatic alkyl group or an aromatic heterocyclic group which may have a substituent, the hydrogen atom contained in the alkyl group, the aromatic alkyl group or the aromatic heterocyclic group may be substituted by a halogen atom, the -CH 2 - contained in the alkyl group may be substituted by -O-, -CO-, -O-CO- or -CO-O-, Y 1} represents an alkyl group having 1 to 6 carbon atoms, an aromatic alkyl group or an aromatic heterocyclic group which may have a substituent, the hydrogen atom contained in the alkyl group, the aromatic alkyl group or the aromatic heterocyclic group may be substituted by a halogen atom, the -CH ₂ - contained in the alkyl group may be substituted by -O-, -CO-, -O-CO- or -CO-O-, ^Z2 represents a CN group or an alkyl group having 1 to 12 carbon atoms which may have a substituent. The hydrogen atom contained in the alkyl group may be substituted by a halogen atom. The _-CH2- contained in the alkyl group may be substituted by -O-, -CO-, -O-CO- or -CO-O-. ^Z1 , ^Z2 and ^Z3 each independently represent a hydrogen atom or an aliphatic hydrocarbon group or an alkoxy group having 1 to 20 carbon atoms, an alicyclic hydrocarbon group having 3 to 20 carbon atoms, a monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms, a halogen atom, a ^cyano group, a nitro group, ^-NR15R16 or ^-SR15 . ^Z1 and ^Z2 may also be bonded to each other to form an aromatic ring or an aromatic heterocyclic ring. ^R15 and R ¹⁶ each independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms; Ax represents an organic group having 2 to 30 carbon atoms and having at least one aromatic ring selected from the group consisting of aromatic hydrocarbon rings and aromatic heterocyclic rings; Ay represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms which may have a substituent, or an organic group having 2 to 30 carbon atoms and having at least one aromatic ring selected from the group consisting of aromatic hydrocarbon rings and aromatic heterocyclic rings; Ax and Ay may also be bonded to form a ring; ^Y3 and ^Y4 each independently represent a group selected from the following formula (Y-1):

[In formula (Y-1), ^M1 represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and the alkyl group may be substituted by one or more substituents ^X3 , and the substituents ^X3 represent fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, pentafluorosulfur groups, nitro groups, cyano groups, isocyano groups, amino groups, hydroxyl groups, hydroxyl groups, methylamino groups, dimethylamino groups, diethylamino groups, diisopropylamino groups, trimethylsilyl groups, dimethylsilyl groups, isothiocyano groups, or one _-CH2- or two or more non-adjacent -CH2- _groups. - a linear or branched alkyl group having 1 to 20 carbon atoms which may be independently substituted by -O-, -S-, -CO-, -COO-, -OCO-, -CO-S-, -S-CO-, -O-CO-O-, -CO-NH-, -NH-CO-, -CH=CH-COO-, -CH=CH-OCO-, -COO-CH=CH-, -OCO-CH=CH-, -CH=CH-, -CF=CF- or -C≡C-, any hydrogen atom in the alkyl group may be substituted by a fluorine atom, or may be a group represented by -B11- ^F11 - ^P11 , ^B11 , ^F11 and ^P11 are respectively defined in the same manner as ^B1 , ^F1 and ^P1 in the above formula (1), and may be respectively substituted by ^B1 , ^F1 and P1 as above ^{. 1} are the same or different; U ¹ represents an organic group having 2 to 30 carbon atoms and having an aromatic alkyl group, any carbon atom of the aromatic alkyl group may be substituted with a heteroatom, and the aromatic alkyl group may be substituted with one or more of the substituents X ³ mentioned above; T ¹ represents -O-, -S-, -COO-, -OCO-, -OCO-O-, -NU ² -, -N=CU ² -, -CO-NU ² -, -OCO-NU ² -, or -O-NU ² -, and U ² represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 12 carbon atoms, a cycloalkenyl group having 3 to 12 carbon atoms, an organic group having 2 to 30 carbon atoms and having an aromatic alkyl group (any carbon atom of the aromatic alkyl group may be substituted with a heteroatom), or (E ¹¹ -A ¹¹ ) _q -B ¹² -F ¹² -P ¹² , the alkyl, cycloalkyl, cycloalkenyl and aromatic hydrocarbon group are unsubstituted or substituted with one or more substituents X ³ , the alkyl group may be substituted with the cycloalkyl or cycloalkenyl group, one -CH ₂ - or two or more non-adjacent -CH ₂ - in the alkyl group may be independently substituted with -O-, -S-, -CO-, -COO-, -OCO-, -CO-S-, -S-CO-, -SO _{2 -, -O-CO-O-, -CO-NH-, -NH-CO-, -CH=CH-COO-, -CH=CH-OCO-, -COO-CH=CH-, -OCO-CH=CH-, -CH=CH-, -CF=CF- or -C≡C-, one -CH 2} in the cycloalkyl or cycloalkenyl group may be substituted with -O-, -S-, -CO-, -COO-, -OCO-, -CO-S-, -S-CO-, -SO 2 -, -O-CO-O-, -CO-NH-, -NH-CO-, -CH=CH-COO-, -CH=CH-OCO-, -COO-CH=CH-, -OCO- _CH =CH-, -CH=CH-, -CF=CF- or -C≡C- - or two or more non-adjacent -CH ₂ - may be independently substituted with -O-, -CO-, -COO-, -OCO- or -O-CO-O-; E ¹¹ , A ¹¹ , B ¹² , F ¹² and P ¹² are defined similarly to E ¹ , A ¹ , B ¹ , F ¹ and P ¹ in formula (1), and may be the same as or different from the above-mentioned E ¹ , A ¹ , B ¹ , F ¹ and P ¹ ; q represents an integer of 0 to 4, and when there are plural E ¹¹ and/or A ¹¹ , they may be the same as or different; U ¹ and U ² may be bonded to form a ring]]. The polymerizable liquid crystal composition of claim 1 or 2, wherein ^A1 and ^A2 in formula (1) are independently 1,4-cyclohexanediyl or 1,4-phenylenediyl. The polymerizable liquid crystal composition of claim 1 or 2, wherein ^P1 and ^P2 in formula (1) are respectively acryl groups. The polymerizable liquid crystal composition of claim 1 or 2 further comprises a photopolymerization initiator. The polymerizable liquid crystal composition of claim 1 or 2 further comprises an organic solvent. A phase difference film comprising a liquid crystal cured film which is a cured product of a polymerizable liquid crystal composition as described in any one of claims 1 to 6. As claimed in claim 7, the phase difference film, wherein the liquid crystal cured film satisfies formula (i): 0.75≦Re(450)/Re(550)<1.00 (i) [in formula (i), Re(λ) represents the in-plane phase difference value of the liquid crystal cured film at a wavelength of λ nm]. An elliptical polarizing plate comprising a phase difference film as claimed in claim 7 or 8. An optical display comprising an elliptical polarizing plate as claimed in claim 9. A flexible image display device, comprising an elliptical polarizing plate as claimed in claim 9.