JP7680217B2 - Polymerizable liquid crystal mixture, polymerizable liquid crystal composition - Google Patents

Description

The present invention relates to a polymerizable liquid crystal compound, a polymerizable liquid crystal composition containing the polymerizable liquid crystal compound, and a retardation film, a polarizing plate, and an optical display formed from the polymerizable liquid crystal composition.

As an optical film such as a retardation film used in a flat panel display device (FPD), for example, there is an optical film obtained by dissolving a polymerizable liquid crystal compound in a solvent, applying the coating liquid obtained by dissolving the polymerizable liquid crystal compound in a solvent to a support substrate, and then polymerizing the coating liquid. Conventionally, as a polymerizable liquid crystal compound, for example, a nematic liquid crystal compound having a rod-shaped structure in which about 2 to 4 six-membered rings are connected is known. On the other hand, as one of the characteristics of a retardation film, it is required that the film is capable of polarization conversion in the entire wavelength range. For example, in a wavelength range where the value [Re(λ)/Re(550)] obtained by dividing the retardation value Re(λ) at a certain wavelength λ by the retardation value Re(550) at 550 nm is close to 1, or in a wavelength range showing a reverse wavelength dispersion of [Re(450)/Re(550)]<1, it is known that a uniform polarization conversion is theoretically possible. Polymerizable liquid crystal compounds that can constitute such retardation films are disclosed, for example, in Patent Documents 1 to 3.

JP 2016-121339 A JP 2019-156733 A JP 2020-41026 A

When orienting a polymerizable liquid crystal compound, for example, a coating liquid containing the polymerizable liquid crystal compound must be applied to a support substrate, and then the polymerizable liquid crystal compound must be heated to a temperature higher than the phase transition temperature to cause a phase transition. If the phase transition temperature of the polymerizable liquid crystal compound is high, it may have an undesirable effect on the support substrate, the usable support substrates may be limited, or the heating temperature may become high, resulting in poor manufacturing efficiency. In addition, if an additive is added to the polymerizable liquid crystal compound for the purpose of lowering the phase transition temperature, the molecular orientation of the liquid crystal compound may be disturbed by the additive, and the desired optical properties may not be obtained. Furthermore, the additive or the polymerizable liquid crystal compound may precipitate as crystals, which may also prevent the desired optical properties from being obtained.

The present invention aims to provide a compound that can lower the phase transition temperature of a liquid crystal composition without impairing the optical properties.

The present inventors have conducted extensive research to solve the above problems and have completed the present invention. That is, the present invention provides the following preferred embodiments.
[1] A polymerizable liquid crystal compound represented by formula (1).
[In formula (1),
k11, k12 and l each independently represent an integer of 1 or more;
B ¹¹ and B ¹² each independently represent -CR ¹ R ² -, -CH ₂ -CH ₂ -, -O-, -S-, -CO-O-, -O-CO-, -O-CO-O-, -C(=S)-O-, -O-C(=S)-, -O-C(=S)-O-, -CO-NR ¹ -, -NR ² -CO-, -O-CH ₂ -, -CH ₂ -O-, -S-CH ₂ -, -CH ₂ -S- or a single bond, and R ¹ and R ² each independently represent a hydrogen atom, a fluorine atom or an alkyl group having 1 to 4 carbon atoms;
E ¹¹ and E ¹² each independently represent -CR ¹ R ² -, -CH ₂ -CH ₂ -, -O-, -S-, -CO-O-, -O-CO-, -O-CO-O-, -C(=S)-O-, -O-C(=S)-, -O-C(=S)-O-, -CO-NR ¹ -, -NR ² -CO-, -O-CH 2 -, -CH ₂ -O-, -S-CH _{2 -} , -CH ₂ -S- or a single bond;
G ¹¹ and G ¹² each independently represent a divalent alicyclic hydrocarbon group having 3 to 16 carbon atoms, a hydrogen atom contained in the alicyclic hydrocarbon group may be substituted with a halogen atom, -R ³ , -OR ³ , a cyano group or a nitro group, -CH ₂ - contained in the alicyclic hydrocarbon group may be substituted with -O-, -S- or -NH-, R ³ represents an alkyl group having 1 to 4 carbon atoms, and a hydrogen atom contained in the alkyl group may be substituted with a fluorine atom;
A ¹¹ and A ¹² each independently represent a divalent alicyclic hydrocarbon group having 3 to 16 carbon atoms, or a divalent aromatic hydrocarbon group having 6 to 20 carbon atoms, and a hydrogen atom contained in the alicyclic hydrocarbon group or the aromatic hydrocarbon group may be substituted with a halogen atom, -R ³ , -OR ³ , a cyano group, or a nitro group;
F ¹¹ and F ¹² each independently represent an alkanediyl group having 1 to 12 carbon atoms, a hydrogen atom contained in the alkanediyl group may be substituted with -OR ³ or a halogen atom, and -CH ₂ - contained in the alkanediyl group may be substituted with -O- or -CO-;
P ¹¹ and P ¹² each independently represent a hydrogen atom or a polymerizable group (provided that at least one of P ¹¹ and P ¹² is a polymerizable group);
Each M independently represents a divalent aliphatic hydrocarbon group having 3 to 13 carbon atoms which may have a substituent;
Ar ¹¹ and Ar ¹² each independently represent a divalent aromatic group which may have a substituent.
[2] The polymerizable liquid crystal compound according to the above [1], wherein M in formula (1) is a divalent aliphatic hydrocarbon group having 2n carbon atoms (n is an integer of 2 to 4) which may have a substituent.
[3] The polymerizable liquid crystal compound according to the above [1] or [2], wherein Ar ¹¹ and Ar ¹² in formula (1) are each independently a group represented by any one of the following formulae (Ar-1) to (Ar-5):
[In formulas (Ar-1) to (Ar-5),
* represents a bond;
^Q1 represents -S-, -O- or ^-NR11- , ^R11 represents a hydrogen atom or an optionally substituted alkyl group having 1 to 6 carbon atoms;
^Q2 represents a hydrogen atom or an optionally substituted alkyl group having 1 to 6 carbon atoms;
W ¹ and W ² each independently represent -O-, -S-, -CO- or -NR ¹¹ -, where R ¹¹ represents a hydrogen atom or an optionally substituted alkyl group having 1 to 6 carbon atoms;
Y ¹ represents an alkyl group having 1 to 6 carbon atoms, an aromatic hydrocarbon group which may have a substituent, or an aromatic heterocyclic group which may have a substituent;
^Y2 represents a CN group or an alkyl group having 1 to 12 carbon atoms which may have a substituent, a hydrogen atom contained in the alkyl 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-;
Z ¹ , Z ² and Z ³ each independently represent a hydrogen atom, 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, -NR ¹¹ R ¹² or -SR ¹¹ , Z ¹ and Z ² may bond to each other to form an aromatic ring or an aromatic heterocycle, and R ¹¹ and R ¹² 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 having at least one aromatic ring selected from the group consisting of aromatic hydrocarbon rings and aromatic heterocycles, 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 heterocycles, and Ax and Ay may be bonded to form a ring;
Y ³ and Y ⁴ each independently represent the following formula (Y ³ -1):
[In formula (Y ³ -1),
R ^Y1 represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and the alkyl group may be substituted with one or more substituents X ³ , and the substituents X ³ represent a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a pentafluorosulfuranyl group, a nitro group, a cyano group, an isocyano group, an amino group, a hydroxyl group, a mercapto group, a methylamino group, a dimethylamino group, a diethylamino group, a diisopropylamino group, a trimethylsilyl group, a dimethylsilyl group, a thioisocyano group, or one -CH ₂ - or two or more non-adjacent -CH _{2 -} groups. each independently represents a linear or branched alkyl group having 1 to 20 carbon atoms which may be replaced 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-, and any hydrogen atom in the alkyl group may be replaced by a fluorine atom or may be a group represented by -B ³¹ -F ³¹ -P ³¹ , B ³¹ , F ³¹ and P ³¹ are defined the same as B ¹¹ , F ¹¹ and P ¹¹ in formula (1), ^respectively , ^and may be the same as or different from ¹¹ ;
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 with a heteroatom, and the aromatic hydrocarbon group may be substituted with one or more of the substituents X ³ ;
T ¹ represents -O-, -S-, -COO-, -OCO-, -OCO-O-, -NU ² -, -N═CU ² -, -CO-NU 2 -, -OCO-NU ² - or ^{O-NU 2 -} ; 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 an aromatic hydrocarbon group (any carbon atom of the aromatic hydrocarbon group may be substituted with a heteroatom), or (E ³¹ -A ³¹ ) _q -B ³² -F ³² -P ³² ; each of the alkyl group, cycloalkyl group, cycloalkenyl group and aromatic hydrocarbon group may be unsubstituted or substituted with one or more substituents X ³ , the alkyl group may be substituted with the cycloalkyl group or cycloalkenyl group, and one -CH ₂ - or two or more nonadjacent -CH ₂ - may each independently be replaced by -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 nonadjacent -CH ₂ - in the cycloalkyl group or cycloalkenyl group may each independently be replaced by -O-, -CO-, -COO-, -OCO- or O-CO-O-; E ³¹ , A ³¹ , B ³² , F ³² and P ³² are each defined the same as E ¹¹ , A ¹¹ , B ¹¹ , F ¹¹ and P ¹¹ in formula (1), and may be the same or different from E ¹¹ , A ¹¹ , B ¹¹ , F ¹¹ and P ^11, respectively; q represents an integer of 0 to 4; when a plurality of E ³¹ and/or A ³¹ are present, they may be the same or different; and U ¹ and U ² may be bonded to form a ring.
represents a group selected from the following:
[4] A polymerizable liquid crystal composition comprising the polymerizable liquid crystal compound according to any one of [1] to [3] above and a polymerizable liquid crystal compound represented by formula (2):
[In formula (2),
k21 and k22 each independently represent an integer of 1 or more;
B ²¹ and B ²² each independently represent -CR ¹ R ² -, -CH ₂ -CH ₂ -, -O-, -S-, -CO-O-, -O-CO-, -O-CO-O-, -C(═S)-O-, -O-C(═S)-, -O-C(═S)-O-, -CO-NR ¹ -, -NR ² -CO-, -O-CH ₂ -, -CH ₂ -O-, -S-CH ₂ -, -CH ₂ -S- or a single bond; R ¹ and R ² each independently represent a hydrogen atom, a fluorine atom or an alkyl group having 1 to 4 carbon atoms.
E ²¹ and E ²² each independently represent -CR ¹ R ² -, -CH ₂ -CH ₂ -, -O-, -S-, -CO-O-, -O-CO-, -O-CO-O-, -C(=S)-O-, -O-C(=S)-, -O-C(=S)-O-, -CO-NR ¹ -, -NR ² -CO-, -O-CH 2 -, -CH ₂ -O-, -S-CH _{2 -} , -CH ₂ -S- or a single bond;
G ²¹ and G ²² each independently represent a divalent alicyclic hydrocarbon group having 3 to 16 carbon atoms, a hydrogen atom contained in the alicyclic hydrocarbon group may be substituted with a halogen atom, -R ³ , -OR ³ , a cyano group or a nitro group, -CH ₂ - contained in the alicyclic hydrocarbon group may be substituted with -O-, -S- or -NH-, R ³ represents an alkyl group having 1 to 4 carbon atoms, a hydrogen atom contained in the alkyl group may be substituted with a fluorine atom;
A ²¹ and A ²² each independently represent a divalent alicyclic hydrocarbon group having 3 to 16 carbon atoms, or a divalent aromatic hydrocarbon group having 6 to 20 carbon atoms, and a hydrogen atom contained in the alicyclic hydrocarbon group or the aromatic hydrocarbon group may be substituted with a halogen atom, -R ³ , -OR ³ , a cyano group, or a nitro group;
F ²¹ and F ²² each independently represent an alkanediyl group having 1 to 12 carbon atoms, a hydrogen atom contained in the alkanediyl group may be substituted with -OR ³ or a halogen atom, and -CH ₂ - contained in the alkanediyl group may be substituted with -O- or -CO-;
P ²¹ and P ²² each independently represent a hydrogen atom or a polymerizable group (provided that at least one of P ²¹ and P ²² is a polymerizable group);
Each Ar ²¹ independently represents a divalent aromatic group which may have a substituent.
[5] The polymerizable liquid crystal composition according to [4] above, in which a ratio of a peak area of the polymerizable liquid crystal compound (1) to a total peak area of the polymerizable liquid crystal compound (1) and the polymerizable liquid crystal compound (2), as measured by liquid chromatography, is 0.1% or more and 50% or less.
[6] The polymerizable liquid ^crystal composition according to the above [4] or [5], wherein the groups represented by A ¹¹ , A ¹² , B ¹¹ , B ¹² , E ¹¹ , E ^{12 ,} F ¹¹ , F 12 , G ¹¹ , G ¹² , P ¹¹ and P ¹² in formula (1) are the same as the groups represented by A ²¹ , A ²² , B ²¹ , B ²² , E ²¹ , E ²² , F ²¹ , F ²² , G ²¹ , G ²² , P ²¹ and P ²² in formula (2), and the groups represented by Ar ¹¹ and Ar 12 in formula (1) are the same as the group represented by Ar ²¹ in formula (2).
[7] The polymerizable liquid crystal composition according to any one of [4] to [6] above, further comprising a photopolymerization initiator and an organic solvent.
[8] A retardation film formed from the polymerizable liquid crystal composition according to any one of [4] to [7] above.
[9] A polarizing plate comprising the retardation film according to [8] above.
[10] An optical display comprising the polarizing plate according to [9] above.

The present invention provides a compound that can lower the phase transition temperature of a liquid crystal composition without impairing the optical properties.

The following describes in detail the embodiments of the present invention. Note that the scope of the present invention is not limited to the embodiments described here, and various modifications can be made without departing from the spirit of the present invention.

<Polymerizable liquid crystal compound>
The polymerizable liquid crystal compound of the present invention has the formula (1):
Hereinafter, the polymerizable liquid crystal compound of the present invention represented by formula (1) will also be referred to as "polymerizable liquid crystal compound (1)".

In formula (1), k11 and k12 each independently represent an integer of 1 or more, and may be, for example, an integer of 1 to 5. The sum of k11 and k12 is preferably 2 to 6, and more preferably 2 to 4. From the viewpoint of excellent liquid crystal properties, k11 and k12 each independently are preferably 1 or 2, and from the viewpoint of ease of production of the polymerizable liquid crystal compound (1), it is preferable that k11 and k12 are the same number, and in a preferred embodiment of the present invention, both k11 and k12 are 1.

In formula (1), l represents an integer of 1 or more, and may be, for example, an integer of 1 to 8. From the viewpoint of excellent liquid crystal properties, l is preferably 1 to 6.

In formula (1), B ¹¹ and B ¹² each independently represent -CR ¹ R ² -, -CH ₂ -CH ₂ -, -O-, -S-, -CO-O-, -O-CO-, -O-CO-O-, -C(═S)-O-, -O-C(═S)-, -O-C(═S)-O-, -CO-NR ¹ -, -NR ² -CO-, -O-CH ₂ -, -CH ₂ -O-, -S-CH ₂ -, -CH ₂ -S- or a single bond; and R ¹ and R ² each independently represent a hydrogen atom, a fluorine atom or an alkyl group having 1 to 4 carbon atoms. B ¹¹ and B ¹² are each independently preferably -CO-O-, -O-CO-, -O-CO-O-, -CO-NR ¹ -, -NR ² -CO-, -CH ₂ -O-, -O-CH ₂ -, -CH ₂ -S-, -S-CH ₂ - or a single bond, more preferably -O-CO- or -CO-O-. When a plurality of ^{B 11} and B ¹² are present, they may be the same or different from each other, but from the viewpoint of ease of production of the polymerizable liquid crystal compound (1), it is preferable that a plurality of B ¹¹ are the same group, and it is preferable that a plurality of B ¹² are the same group. It is more preferable that all B ¹¹ and B ¹² are the same.

Examples of the alkyl group having 1 to 4 carbon atoms represented by ^R1 and ^R2 include a methyl group, an ethyl group, a propyl group, a butyl group, an isopropyl group, an isobutyl group, and a tert-butyl group. An alkyl group having 1 or 2 carbon atoms is preferable, and a methyl group is more preferable.

In formula (1), E ¹¹ and E ¹² each independently represent -CR ¹ R ² -, -CH ₂ -CH ₂ -, -O-, -S-, -CO-O-, -O-CO-, -O-CO-O-, -C(═S)-O-, -O-C(═S)-, -O-C(═S)-O-, -CO-NR ¹ -, -NR ² -CO-, -O-CH ₂ -, -CH ₂ -O-, -S-CH ₂ -, -CH ₂ -S- or a single bond. E ¹¹ and E ¹² are each independently preferably -CO-O-, -O-CO-, -O-CO-O-, -CO-NR ¹ -, -NR ² -CO-, -CH ₂ -O-, -O-CH ₂ -, -CH ₂ -S-, -S-CH ₂ - or a single bond, and more preferably -O-CO- or -CO-O-. From the viewpoint of ease of production of the polymerizable liquid crystal compound (1), E ¹¹ and E ¹² may be the same or different from each other, but are preferably the same group.

G ¹¹ and G ¹² each independently represent a divalent alicyclic hydrocarbon group having 3 to 16 carbon atoms. A hydrogen atom contained in the alicyclic hydrocarbon group may be substituted with a halogen atom, -R ³ , -OR ³ , a cyano group or a nitro group, and -CH ₂ - contained in the alicyclic hydrocarbon group may be substituted with -O-, -S- or -NH-. R ³ represents an alkyl group having 1 to 4 carbon atoms, and a hydrogen atom contained in the alkyl group may be substituted with a fluorine atom. Examples of the divalent alicyclic hydrocarbon group having 3 to 16 carbon atoms represented by G ¹¹ and G ¹² include divalent alicyclic hydrocarbon groups which may contain a heteroatom and are represented by formulae (g-1) to (g-10), and a 5- or 6-membered alicyclic hydrocarbon group is preferable.

The groups represented by the above formulas (g-1) to (g-10) may be substituted with an alkyl group having 1 to 4 carbon atoms, such as a methyl group, an ethyl group, an isopropyl group, or a tert-butyl group; an alkoxy group having 1 to 4 carbon atoms, such as a methoxy group or an ethoxy group; a fluoroalkyl group having 1 to 4 carbon atoms, such as a trifluoromethyl group; a cyano group; a nitro group; or a halogen atom, such as a fluorine atom, a chlorine atom, or a bromine atom.

G ¹¹ and G ¹² are each preferably a 5- or 6-membered alicyclic hydrocarbon group represented by any one of formulas (g-1) to (g-4), more preferably a 6-membered alicyclic hydrocarbon group represented by formula (g-1), particularly preferably a cyclohexane-1,4-diyl group, and particularly preferably a trans-cyclohexane-1,4-diyl group.
G ¹¹ and G ¹² may be the same or different from each other, but when they are the same, it is advantageous in terms of ease of industrial production of the polymerizable liquid crystal compound (1) and productivity.

In formula (1), A ¹¹ and A ¹² each independently represent a divalent alicyclic hydrocarbon group having 3 to 16 carbon atoms, or a divalent aromatic hydrocarbon group having 6 to 20 carbon atoms, and a hydrogen atom contained in the alicyclic hydrocarbon group or the aromatic hydrocarbon group may be substituted with a halogen atom, -R ³ , -OR ³ , a cyano group, or a nitro group.

Examples of the divalent alicyclic hydrocarbon group having 3 to 16 carbon atoms or the divalent aromatic hydrocarbon group having 6 to 20 carbon atoms represented by A ¹¹ and A ¹² include alicyclic hydrocarbon groups consisting of a 5-membered or 6-membered ring represented by the above formulas (g-1) to (g-10) and aromatic hydrocarbon groups having about 6 to 20 carbon atoms represented by formulas (a-1) to (a-8).

In addition, some of the hydrogen atoms of the groups exemplified as A ¹¹ and A ¹² may be substituted with an alkyl group having 1 to 4 carbon atoms, such as a methyl group, an ethyl group, an isopropyl group, or a tert-butyl group; an alkoxy group having 1 to 4 carbon atoms, such as a methoxy group or an ethoxy group; a fluoroalkyl group having 1 to 4 carbon atoms, such as a trifluoromethyl group; a cyano group; a nitro group; or a halogen atom, such as a fluorine atom, a chlorine atom, or a bromine atom.

A ¹¹ and A ¹² are preferably a cyclohexane-1,4-diyl group or a 1,4-phenylene group. When k11 and k12 are 1, A ¹¹ and A ¹² are preferably 1,4-phenylene groups, and when k11 and k12 are 2 or more, A ¹¹ bonded to E ¹¹ and A ¹² bonded to E ¹² are preferably the same, and A ¹¹ bonded to E ¹¹ and A ¹² bonded to E ¹² are preferably 1,4-phenylene groups. When a plurality of ^{A 11} and A ¹² are present, they may be the same or different.

In formula (1), F ¹¹ and F ¹² each independently represent an alkanediyl group having 1 to 12 carbon atoms, a hydrogen atom contained in the alkanediyl group may be substituted with -OR ³ or a halogen atom, and -CH ₂ - contained in the alkanediyl group may be substituted with -O- or -CO-. ^{F 11} and F ¹² each independently preferably represent an alkanediyl group having 3 to 10 carbon atoms, -(CF ₂ ) ₄ -, -(CF ₂ ) ₆ -, or -(CF ₂ ) ₈ -, and more preferably an alkanediyl group having 4 or 6 carbon atoms [-(CH ₂ ) ₄ - or -(CH ₂ ) ₆ -]. ^{E 11} and E ¹² may be the same or different from each other, but being the same is advantageous in terms of ease of industrial production of the polymerizable liquid crystal compound (1) and productivity.

^P11 and ^P12 each independently represent a hydrogen atom or a polymerizable group. At least one of ^P11 and ^P12 is a polymerizable group, and it is preferable that both ^P11 and ^P12 are polymerizable groups from the viewpoint of the film hardness of the liquid crystal cured film obtained by using the polymerizable liquid crystal compound.

The polymerizable group may be any reactive group capable of polymerizing the polymerizable liquid crystal compound (1), and specific examples thereof include a vinyl group, a vinyloxy group, a styryl group, a p-(2-phenylethenyl)phenyl group, an acryloyl group, a methacryloyl group, an acryloyloxy group, a methacryloyloxy group, a carboxy group, an acetyl group, a hydroxy group, a carbamoyl group, an N-alkylamino group having 1 to 4 carbon atoms, an amino group, an oxiranyl group, an oxetanyl group, a formyl group, an isocyanato group, an isothiocyanato group, etc. The polymerizable group may contain an ether bond or an ester bond that bonds the above-mentioned groups to F ¹¹ or F ¹² , and each is preferably bonded via an ether bond. As ^P11 and ^P12 , for example, a radical polymerizable group or a cationically polymerizable group suitable for photopolymerization is preferable, and an acryloyloxy group or a methacryloyloxy group is particularly preferable because it is easy to handle and to produce, and an acryloyloxy group is more preferable.

In formula (1), M each independently represents a divalent aliphatic hydrocarbon group having 3 to 13 carbon atoms which may have a substituent. When M in formula (1) is a divalent aliphatic hydrocarbon group having 3 to 13 carbon atoms, it is easy to improve the solubility in a solvent of other polymerizable liquid crystal compounds having a structure similar to that of the polymerizable liquid crystal compound (1) in the molecular structure, such as a polymerizable liquid crystal compound represented by formula (2) described later, and is excellent in the effect of lowering the phase transition temperature of the polymerizable liquid crystal compound. Since it is excellent in the effect of lowering the phase transition temperature of the polymerizable liquid crystal compound, a liquid crystal cured film can be obtained from the polymerizable liquid crystal compound at a lower processing temperature, it is also advantageous in terms of reducing the influence of heating on the optical properties of the liquid crystal cured film and in terms of production efficiency. Such an effect tends to be significantly higher, particularly compared to when M in formula (1) is a structure having a cyclic structure such as an alicyclic hydrocarbon group or an aromatic hydrocarbon group. The reason for this is presumably, but not limited to, that the group M located between the divalent aromatic groups (Ar ¹¹ and/or Ar ¹² ) does not have a rigid cyclic structure, which increases the flexibility of the molecule and makes it easier to improve the solubility, resulting in a significant decrease in the phase transition temperature.

The divalent aliphatic hydrocarbon group having 3 to 13 carbon atoms may be linear or branched, and may be a saturated or unsaturated hydrocarbon, but is preferably a saturated hydrocarbon group, and more preferably a linear saturated hydrocarbon group. Specific examples of the divalent aliphatic hydrocarbon group having 3 to 13 carbon atoms include alkanediyl groups having 3 to 13 carbon atoms, such as n-propanediyl, i-propanediyl, n-butanediyl, n-pentanediyl, n-hexanediyl, n-heptanediyl, n-octanediyl, n-nonanediyl, and n-decanediyl. When there are multiple M's, they may be the same or different.

The hydrogen atom contained in the divalent aliphatic hydrocarbon group having 3 to 13 carbon atoms may be replaced by a substituent. When M in formula (1) is a divalent aliphatic hydrocarbon group having 3 to 13 carbon atoms and having a substituent, it is preferable that no cyclic structure is present in M including the substituent. In other words, the polymerizable liquid crystal compound (1) of the present invention does not contain a cyclic structure other than the alicyclic hydrocarbon group or aromatic hydrocarbon group represented by the group Ar ¹¹ in the structure represented by -(Ar ¹¹ -O-CO-M-CO-O)- in formula (1). Examples of the substituent that the divalent aliphatic hydrocarbon group having 3 to 13 carbon atoms may have include a halogen atom and an alkoxyl group having 1 to 4 carbon atoms. The number of carbon atoms contained in the substituent is not included in the number of carbon atoms of the aliphatic hydrocarbon group represented by M in formula (1).

Furthermore, when M in formula (1) is a divalent aliphatic hydrocarbon group having 2n carbon atoms (n is an integer from 2 to 4) which may have a substituent, the resulting liquid crystal cured film can exhibit better reverse wavelength dispersion while adequately ensuring the effect of lowering the phase transition temperature of the polymerizable liquid crystal compound and the effect of improving solubility. As the divalent aliphatic hydrocarbon group having 2n carbon atoms, an alkanediyl group having 2n carbon atoms is preferred, specifically, an n-butanediyl group, an n-hexanediyl group, or an n-octanediyl group.

In formula (1), M is preferably a divalent alkanediyl group having 3 to 11 carbon atoms which may have a substituent, more preferably a divalent alkanediyl group having 4 to 10 carbon atoms which may have a substituent, even more preferably a divalent alkanediyl group having 4, 6 or 8 carbon atoms which may have a substituent, and particularly preferably an n-butanediyl group, an n-hexanediyl group or an n-octanediyl group.

In formula (1), Ar ¹¹ and Ar ¹² each independently represent a divalent aromatic group which may have a substituent. The divalent aromatic group which may have a substituent may be a divalent aromatic heterocyclic group and a divalent aromatic heterocyclic group. In the present invention, the divalent aromatic hydrocarbon group which may have a substituent means a divalent linking group containing at least one aromatic hydrocarbon ring, and the divalent aromatic heterocyclic group which may have a substituent means a divalent linking group containing at least one aromatic heterocycle. The aromatic hydrocarbon ring and aromatic heterocycle referred to here refer to those in which the number of π electrons in the ring structure is [4n+2] (n represents an integer) according to the Huckel rule (in the case of an aromatic heterocycle, the Huckel rule is satisfied, including non-covalent bond electron pairs on heteroatoms such as -N= and -S-). ^{Ar 11} and Ar ¹² may contain one aromatic hydrocarbon ring or aromatic heterocycle, or may contain two or more. When one aromatic hydrocarbon ring or aromatic heterocycle is included, Ar ¹¹ and Ar ¹² may each independently be a divalent aromatic hydrocarbon group which may have a substituent, or a divalent aromatic heterocyclic group which may have a substituent. When two or more aromatic hydrocarbon rings or aromatic heterocycles are included, only aromatic hydrocarbon rings or only aromatic heterocycles may be included, or one or more aromatic hydrocarbon rings and aromatic heterocycles may be included. Two or more aromatic hydrocarbon rings and/or aromatic heterocycles may be bonded to each other via a divalent bonding group such as a single bond, -CO-O-, -O-, etc.

Ar ¹¹ and Ar ¹² may be the same or different from each other, but being the same is advantageous in terms of ease of industrial production and productivity of the polymerizable liquid crystal compound (1). In addition, when there are multiple Ar ^11s , the multiple Ar ^11s may be the same or different, but are preferably the same group, and it is more preferable that the multiple Ar ^11s and Ar ^12s are all the same.

Examples of aromatic hydrocarbon rings that can be included in Ar ¹¹ and Ar ¹² include benzene ring, naphthalene ring, anthracene ring, etc., and benzene ring and naphthalene ring are preferred. Examples of aromatic heterocycles include furan ring, benzofuran ring, pyrrole ring, indole ring, thiophene ring, benzothiophene ring, pyridine ring, pyrazine ring, pyrimidine ring, triazole ring, triazine ring, pyrroline ring, imidazole ring, pyrazole ring, thiazole ring, benzothiazole ring, thienothiazole ring, oxazole ring, benzoxazole ring, and phenanthroline ring. When Ar ¹¹ and Ar ¹² include a nitrogen atom, it is preferred that the nitrogen atom has π electrons.

Among them, Ar ¹¹ and Ar ¹² preferably have an aromatic heterocycle containing at least two heteroatoms selected from the group consisting of nitrogen atoms, oxygen atoms and sulfur atoms, more preferably have a thiazole ring, a benzothiazole ring or a benzofuran ring, and even more preferably have a benzothiazole ring. In addition, when Ar ¹¹ and Ar ¹² have an aromatic heterocycle containing at least two heteroatoms selected from the group consisting of nitrogen atoms, oxygen atoms and sulfur atoms, the aromatic heterocycle may be directly bonded to -CO-O- or -O-CO- adjacent to G ¹¹ , M or G ¹² in formula (1) to constitute a divalent linking group constituting the main chain of the compound represented by formula (1), and may be included as a substituent of a divalent linking group directly bonded to -CO-O- or -O-CO- adjacent to G ¹¹ , M or G ¹² , respectively, but it is preferable that the entire Ar ¹¹ or Ar ¹² group containing the aromatic heterocycle is stereo-configured in a direction approximately perpendicular to the molecular orientation direction.

In formula (1), the total number _Nπ of π electrons contained in the divalent aromatic groups which may have a substituent represented by Ar ¹¹ and Ar ¹² is preferably 8 or more, more preferably 12 or more, particularly preferably 16 or more, and especially preferably 20 or more. Also, it is preferably 36 or less, more preferably 32 or less, even more preferably 30 or less, particularly preferably 26 or less, and especially preferably 24 or less.

Examples of the optionally substituted divalent aromatic groups represented by Ar ¹¹ and Ar ¹² in formula (1) include groups represented by the following formulae (Ar-1) to (Ar-5).

In formulas (Ar-1) to (Ar-5), * represents a bond.

In formula (Ar-1), ^Q1 represents -S-, -O- or ^-NR11- , where ^R11 represents a hydrogen atom or an optionally substituted alkyl group having 1 to 6 carbon atoms. In formulas (Ar-3) and (Ar-4), ^Q2 represents a hydrogen atom or an optionally substituted alkyl group having 1 to 6 carbon atoms.

In formula (Ar-2), W ¹ and W ² each independently represent --O--, --S--, --CO-- or --NR ¹¹ --, where R ¹¹ represents a hydrogen atom or an optionally substituted alkyl group having 1 to 6 carbon atoms.

In formula (Ar-1), ^Y1 represents an alkyl group having 1 to 6 carbon atoms, an aromatic hydrocarbon group which may have a substituent, or an aromatic heterocyclic group. In formula (Ar-2), ^Y2 represents a CN group or an alkyl group having 1 to 12 carbon atoms which may have a substituent. Here, a hydrogen atom contained in the alkyl 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 (Ar-1) to (Ar-5), Z ¹ , Z ² and Z ³ each independently represent a hydrogen atom, 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, -NR ¹¹ R ¹² or -SR ¹¹ , and Z ¹ and Z ² may be bonded to each other to form an aromatic ring or an aromatic heterocycle. R ¹¹ and R ¹² each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.

In formulae (Ar-3) and (Ar-4), 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 heterocycles, 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 heterocycles, and Ax and Ay may be bonded to form a ring.

In formula (Ar-1), Y ¹ is preferably an aromatic hydrocarbon group or aromatic heterocyclic group which may have a substituent, and is more preferably an aromatic hydrocarbon group having 6 to 12 carbon atoms or an aromatic heterocyclic group having 3 to 12 carbon atoms which may have a substituent. The aromatic hydrocarbon group or aromatic heterocyclic group which may have a substituent is preferably a polycyclic aromatic hydrocarbon group or a polycyclic aromatic heterocyclic group which may have a substituent. In this specification, the term "polycyclic aromatic hydrocarbon group" means an aromatic hydrocarbon group having at least two aromatic rings, and examples of such groups include a fused aromatic hydrocarbon group formed by condensing two or more aromatic rings and an aromatic hydrocarbon group formed by bonding two or more aromatic rings. The term "polycyclic aromatic heterocyclic group" refers to an aromatic heterocyclic group having at least one heteroaromatic ring and having at least one ring selected from the group consisting of aromatic rings and heteroaromatic rings, and examples of such groups include aromatic heterocyclic groups formed by condensing one or more aromatic heterocyclic rings with one or more rings selected from the group consisting of aromatic rings and heteroaromatic rings, and aromatic heterocyclic groups formed by bonding at least one heteroaromatic ring with at least one ring selected from the group consisting of aromatic rings and heteroaromatic rings.

Substituents that the aromatic hydrocarbon group or aromatic heterocyclic group may have include halogen atoms, alkyl groups having 1 to 6 carbon atoms, cyano groups, nitro groups, nitroso groups, alkylsulfinyl groups having 1 to 6 carbon atoms, alkylsulfonyl groups having 1 to 6 carbon atoms, carboxy groups, fluoroalkyl groups having 1 to 6 carbon atoms, alkoxy groups having 1 to 6 carbon atoms, alkylsulfanyl groups having 1 to 6 carbon atoms, N-alkylamino groups having 1 to 4 carbon atoms, N,N-dialkylamino groups having 2 to 8 carbon atoms, sulfamoyl groups, N-alkylsulfamoyl groups having 1 to 6 carbon atoms, and N,N-dialkylsulfamoyl groups having 2 to 12 carbon atoms.

Examples of Y ¹ include groups represented by the following formulae (Y ¹ -1) to (Y ¹ -7).

In formulae (Y ¹ -1) to (Y ¹ -7), the * moiety represents a linking moiety.

In formulae (Y ¹ -1) to (Y ¹ -7), Z ⁴ each independently represents a halogen atom or an organic group having 1 to 20 carbon atoms, and for example, a fluorine atom, a chlorine atom, a bromine atom, a methyl group, an ethyl group, an isopropyl group, a sec-butyl group, a cyano group, a nitro group, a sulfone group, a nitroxy group, a carboxyl group, a trifluoromethyl group, a methoxy group, a thiomethyl group, an N,N-dimethylamino group, or an N-methylamino group is preferable, a halogen atom, a methyl group, an ethyl group, an isopropyl group, a sec-butyl group, a cyano group, a nitro group, or a trifluoromethyl group is more preferable, and a methyl group, an ethyl group, an isopropyl group, a sec-butyl group, a pentyl group, or a hexyl group is particularly preferable.

In formulae (Y ¹ -1) to (Y ¹ -7), V ¹ and V ² each independently represent -CO-, -S-, -NR ¹³ -, -O-, -Se- or -SO ₂ -, and preferably represent -S-, -NR ¹³ - or -O-. R ¹³ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.

In formulae (Y ¹ -1) to (Y ¹ -7), W ³ to W ⁷ each independently represent -C= or -N=.

In formulae (Y ¹ -1) to (Y ¹ -7), at least one of V ¹ , V ² and W ³ to W ⁷ preferably represents a group containing S, N or O.

In formulae (Y ¹ -1) to (Y ¹ -7), each a independently represents an integer of 0 to 3, and is preferably 0 or 1. Each b independently represents an integer of 0 to 2, and is preferably 0.

Any of the groups represented by formulae (Y ¹ -1) to (Y ¹ -7) is preferably any of the groups represented by the following formulae (Y ¹ -8) to (Y ¹ -13), and more preferably a group represented by formula (Y ¹ -8). In addition, the * portion represents a linking portion.

In formulae (Y ¹ -8) to (Y ¹ -13), Z ⁴ , a, b, V ¹ , V ² and W ³ have the same meanings as Z ⁴ , a, b, V ¹ , V ² and W ³ in formulae (Y ¹ -1) to (Y ¹ -7).

Specific examples of Y ¹ include groups represented by formulae (ar-1) to (ar-840) described in JP-A-2019-003177. Among them, groups represented by the following formulae are preferred.

In one embodiment of the present invention, specific examples of the group represented by formula (Ar-1) include groups represented by the following formulae (Ar ¹ -1) to (Ar ¹ -126), in which the * moiety represents a linking moiety.

In one embodiment of the present invention, specific examples of the group represented by formula (Ar-2) include groups represented by the following formulae (Ar ² -1) to (Ar ² -13), in which the * portion represents a linking portion.

In one embodiment of the present invention, specific examples of the group represented by formula (Ar-3) include groups represented by the following formulae (Ar ³ -1) to (Ar ³ -23), in which the * moiety represents a linking moiety.

The groups represented by formulae (Ar-1) to (Ar-4) may be, in addition to the groups specifically exemplified above, groups described in, for example, JP-A-2011-207765, JP-A-2008-107767, WO2014/010325, etc.

In formula (Ar-5), Y ³ and Y ⁴ each independently represent the following formula (Y ³ -1):
The group represented by the formula:

In formula (Y ³ -1), R ^Y1 represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. The alkyl group may be substituted with one or more substituents ^X3 .

The substituent ^X3 is a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a pentafluorosulfuranyl group, a nitro group, a cyano group, an isocyano group, an amino group, a hydroxyl group, a mercapto group, a methylamino group, a dimethylamino group, a diethylamino group, a diisopropylamino group, a trimethylsilyl group, a dimethylsilyl group, a thioisocyano group, or one -CH ₂ - or two or more non-adjacent -CH _{2 -} groups. each independently represents a linear or branched alkyl group having 1 to 20 carbon atoms which may be replaced 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-, and any hydrogen atom in the alkyl group may be replaced by a fluorine atom or may be a group represented by -B ³¹ -F ³¹ -P ³¹ , B ³¹ , F ³¹ and P ³¹ are defined the same as B ¹¹ , F ¹¹ and P ¹¹ in formula (1), ^respectively , ^and It may be the same as or different from ¹¹ .

The substituent ^X3 is preferably a fluorine atom, a chlorine atom, _—CF3 , _—OCF3 or a cyano group. R ^Y1 is preferably unsubstituted, 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.

In formula (Y ³ -1), U ¹ represents an organic group having 2 to 30 carbon atoms and an aromatic hydrocarbon group. Any carbon atom of the aromatic hydrocarbon group may be substituted with a heteroatom, and U ¹ is 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 heterocycles. The aromatic hydrocarbon group may be substituted with one or more of the substituents X ³ .

^U1 is preferably an organic group having an aromatic heterocycle in which one or more carbon atoms are substituted with a heteroatom, in order to improve wavelength dispersion. ^U1 is more preferably an organic group having an aromatic heterocycle which is a condensed ring of a 5-membered ring and a 6-membered ring, in order to improve wavelength dispersion and show high birefringence.

Specifically, ^U1 is preferably one having a group represented by the following formula: In the following formula, these groups have a bond to ^T1 at any position.

In formula (Y ³ -1), T ¹ represents -O-, -S-, -COO-, -OCO-, -OCO-O-, -NU 2 -, -N═CU ² -, -CO-NU ² -, -OCO-NU 2 - or ^{O-NU 2 - ;} 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 an aromatic hydrocarbon group (any carbon atom of the aromatic hydrocarbon group may be substituted with a heteroatom), or (E ³¹ -A ³¹ ) _q -B ³² -F ³² -P ³² . The alkyl group, the cycloalkyl group, the cycloalkenyl group and the aromatic hydrocarbon group may each be unsubstituted or substituted with one or more substituents ^X3 , and the alkyl group may be substituted with the cycloalkyl group or the cycloalkenyl group. One -CH ₂ - or two or more non-adjacent -CH ₂ - in the alkyl group may each independently be replaced by -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 cycloalkyl group or cycloalkenyl group may each independently be replaced by -O-, -CO-, -COO-, -OCO- or O-CO-O-. E ³¹ , A ³¹ , B ³² , F ³² and P ³² are defined similarly to E ¹¹ , A ¹¹ , B ¹¹ , F ¹¹ and P ¹¹ in formula (1), and may be the same as or different from E ¹¹ , A ¹¹ , B ¹¹ , F ¹¹ and P ¹¹ , respectively, q represents an integer of 0 to 4, and when a plurality of E ³¹ and/or A ³¹ are present, they may be the same as or different from each other.

^T1 is preferably -O-, -S-, -N=CU ² - or -NU ^{2 - in terms of good birefringence and ease of synthesis, and more preferably -O-, -S- or -NU 2 -} in terms of ease of improving wavelength dispersion and birefringence.

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 substituents X ³ , and in which one -CH ₂ - or two or more non-adjacent -CH ₂ - are each independently replaced by -O-, -CO-, -COO-, -OCO- or -O-CO-O-, or the alkyl or alkenyl group may be substituted by the cycloalkyl group, cycloalkenyl group, or aryl group.

Among these, from the viewpoints of birefringence and solvent solubility, ^U2 is more preferably a linear alkyl group having 1 to 20 carbon atoms in which a hydrogen atom may be substituted with a fluorine atom and one _-CH2- or two or more non-adjacent _-CH2- groups may each be independently replaced with -O-, -CO-, -COO- or -OCO-.

U ¹ and U ² may be bonded to form a ring, in which case, for example, a cyclic group represented by -NU ¹ U ² or a cyclic group represented by -N=CU ¹ U ² may be mentioned.

In terms of easy availability of raw materials, good solubility and high birefringence, Y ³ and Y ⁴ particularly preferably each represent a group selected from the following formulae (Y ^3' -1) to (Y ^3' -47).

From the viewpoints of improving the alignment property of the polymerizable liquid crystal compound (1) and facilitating industrial production and improving productivity, specific examples of the group represented by formula (Ar-5) include the following groups: * in the following (Ar ⁵ -1) to (Ar ⁵ -20) represents a bond to -CO-O- or -O-CO- adjacent to G ¹¹ , M or G ¹² , respectively.

Among formulas (Ar-1) to (Ar-5), formulas (Ar-1), (Ar-2) and (Ar-5) are preferred, formulas (Ar-1) and (Ar-5) are more preferred, and formula (Ar-1) is even more preferred.

Specific examples of *-O-CO-G ¹¹ -E ¹¹ -(A ¹¹ -B ¹¹ ) _k11 -F ¹¹ -P ¹¹ and *-O-CO-G ¹² -E ¹² -(A ¹² -B ¹² ) _k12 -F ¹² -P ¹² in formula (1) include structures represented by formulae (R-1) to (R-100). In the formula, * represents a bond to Ar ¹¹ or Ar ¹² , and n represents an integer of 2 to 12. The cyclohexane ring may be in a trans or cis form, but is preferably in a trans form.

The polymerizable liquid crystal composition of the present invention comprises a polymerizable liquid crystal compound (1) of the present invention and a compound represented by the formula (2):
[In formula (2),
k21 and k22 each independently represent an integer of 1 or more;
B ²¹ and B ²² each independently represent -CR ¹ R ² -, -CH ₂ -CH ₂ -, -O-, -S-, -CO-O-, -O-CO-, -O-CO-O-, -C(═S)-O-, -O-C(═S)-, -O-C(═S)-O-, -CO-NR ¹ -, -NR ² -CO-, -O-CH ₂ -, -CH ₂ -O-, -S-CH ₂ -, -CH ₂ -S- or a single bond; R ¹ and R ² each independently represent a hydrogen atom, a fluorine atom or an alkyl group having 1 to 4 carbon atoms.
E ²¹ and E ²² each independently represent -CR ¹ R ² -, -CH ₂ -CH ₂ -, -O-, -S-, -CO-O-, -O-CO-, -O-CO-O-, -C(=S)-O-, -O-C(=S)-, -O-C(=S)-O-, -CO-NR ¹ -, -NR ² -CO-, -O-CH 2 -, -CH ₂ -O-, -S-CH _{2 -} , -CH ₂ -S- or a single bond;
G ²¹ and G ²² each independently represent a divalent alicyclic hydrocarbon group having 3 to 16 carbon atoms, a hydrogen atom contained in the alicyclic hydrocarbon group may be substituted with a halogen atom, -R ³ , -OR ³ , a cyano group or a nitro group, -CH ₂ - contained in the alicyclic hydrocarbon group may be substituted with -O-, -S- or -NH-, R ³ represents an alkyl group having 1 to 4 carbon atoms, a hydrogen atom contained in the alkyl group may be substituted with a fluorine atom;
A ²¹ and A ²² each independently represent a divalent alicyclic hydrocarbon group having 3 to 16 carbon atoms, or a divalent aromatic hydrocarbon group having 6 to 20 carbon atoms, and a hydrogen atom contained in the alicyclic hydrocarbon group or the aromatic hydrocarbon group may be substituted with a halogen atom, -R ³ , -OR ³ , a cyano group, or a nitro group;
F ²¹ and F ²² each independently represent an alkanediyl group having 1 to 12 carbon atoms, a hydrogen atom contained in the alkanediyl group may be substituted with -OR ³ or a halogen atom, and -CH ₂ - contained in the alkanediyl group may be substituted with -O- or -CO-;
P ²¹ and P ²² each independently represent a hydrogen atom or a polymerizable group (provided that at least one of P ²¹ and P ²² is a polymerizable group);
Each Ar ²¹ independently represents a divalent aromatic group which may have a substituent.
The polymerizable liquid crystal compound (hereinafter, also referred to as "polymerizable liquid crystal compound (2)"). By using the polymerizable liquid crystal compound (1) and the polymerizable liquid crystal compound (2) in combination, it is possible to effectively lower the phase transition temperature of the polymerizable liquid crystal compound (2) while suppressing the occurrence of alignment defects. Although the reason for this is not clear, when the polymerizable liquid crystal compound (1) and the polymerizable liquid crystal compound (2) of the present invention have structural units similar to each other, M in formula (1) is an aliphatic hydrocarbon group, and the polymerizable liquid crystal compound (1) has high molecular flexibility, and it is considered that the compatibility between them is increased, and in this state, the phase transition temperature can be significantly lowered while maintaining the high alignment order of the two polymerizable liquid crystal compounds contained. If the phase transition is possible at a low temperature, a liquid crystal cured film can be prepared from the polymerizable liquid crystal compound at a lower processing temperature, and such a liquid crystal cured film can reduce the influence of heating. In particular, from the viewpoint of suppressing the occurrence of alignment defects and easily lowering the phase transition temperature of the polymerizable liquid crystal compound (as a mixture of polymerizable liquid crystal compounds (1) and (2)) without impairing the optical properties, -O-CO-G ¹¹ -E ¹¹ -(A ¹¹ -B ¹¹ ) _k11 -F ¹¹ -P ¹¹ and -O-CO-G ¹² -E ¹² -(A 12 ^{-B 12} ) _k12 -F ¹² -P ¹² of the polymerizable liquid crystal compound (1) of the present invention and -O-CO-G ²¹ -E ²¹ -(A ²¹ -B ²¹ ) _k21 -F ²¹ -P ²¹ and -O-CO-G ²² -E ²² -(A ²² -B ²² ) _k22 It is preferable that —F ²² and —P ²² have similar structural units to each other.

In formula (2), k21 and k22 each independently represent an integer of 1 or more, and may be, for example, an integer of 1 to 5. The sum of k21 and k22 is preferably 2 to 6, and more preferably 2 to 4. From the viewpoint of excellent liquid crystal properties, k21 and k22 each independently are preferably 1 or 2, and from the viewpoint of ease of production of the polymerizable liquid crystal compound (2), it is preferable that k21 and k22 are the same number, and in a preferred embodiment of the present invention, k21 and k22 are both 1. From the viewpoint of excellent liquid crystal properties, it is preferable that k11 and k12 in formula (1) and k21 and k22 in formula (2) are all the same number, and it is more preferable that they are all 1.

In formula (2), the groups represented by ^B21 , ^B22 , ^E21 , ^E22 , ^G21 , ^G22 , ^A21 , ^A22 , ^F21 , ^F22 , ^P21 and ^P22 can be exemplified by the same groups as those exemplified as the groups represented by ^B11 , ^B12 , ^E11 , ^E12 , ^G11 , ^G12 , ^A11 , ^A12 , ^F11 , ^F12 , ^P11 and ^P12 in formula (1), and the same applies to the preferred embodiments of each. In addition, the groups represented by ^Ar21 in formula (2) can be exemplified by the same groups as those exemplified as the groups represented by ^Ar11 and ^Ar12 in formula (1), and the same applies to the preferred embodiments.

It is preferred that the groups represented by A ¹¹ , A ¹² , B ¹¹ , B ¹² , E ¹¹ , E ¹² , F ¹¹ , F ¹² , G ¹¹ , G ¹² , P ¹¹ and P ¹² in formula (1) are the same as the groups represented by A ²¹ , A ²² , B ²¹ , B ²² , E ²¹ , E ²² , F ²¹ , F ²² , G ²¹ , G ²² , P ²¹ and P ²² in formula (2), respectively, and that the groups represented by Ar ¹¹ and Ar ¹² in formula (1) are the same as the group represented by Ar ²¹ in formula (2). When the above group in formula (1) and the above group in formula (2) are in such a relationship, the compatibility between the polymerizable liquid crystal compound (1) and the polymerizable liquid crystal compound (2) is likely to be increased, and the phase transition temperature is likely to be significantly reduced while suppressing alignment defects.

The content of the polymerizable liquid crystal compound (1) and the polymerizable liquid crystal compound (2) in the polymerizable liquid crystal composition of the present invention may be appropriately determined within a range in which the effects of the present invention can be obtained depending on the type of the polymerizable liquid crystal compound (1) and/or the polymerizable liquid crystal compound (2), etc., but it is preferable that the ratio of the peak area of the polymerizable liquid crystal compound (1) to the total peak area of the polymerizable liquid crystal compound (1) and the polymerizable liquid crystal compound (2) measured by liquid chromatography (hereinafter also referred to as "area percentage value") is 0.1% or more and 50% or less. More preferably, it is 1% by mass or more, even more preferably 2% by mass or more, and particularly preferably 3% by mass or more. When the content of the polymerizable liquid crystal compound (1) is equal to or more than the above lower limit, the solubility of the polymerizable liquid crystal compound in a solvent is easily improved and the phase transition temperature is easily sufficiently reduced. In addition, when the content of the polymerizable liquid crystal compound (1) is equal to or less than the above upper limit, the alignment state of the liquid crystal can be well maintained when preparing a liquid crystal cured film from the polymerizable liquid crystal composition containing the polymerizable liquid crystal compound, so that an optical film with excellent optical properties can be obtained. In addition, when a plurality of polymerizable liquid crystal compounds corresponding to the polymerizable liquid crystal compound (1) and/or the polymerizable liquid crystal compound (2) are included, the area percentage value of the polymerizable liquid crystal compound (1) is calculated based on the total peak area of all the polymerizable liquid crystal compounds (1) and all the polymerizable liquid crystal compounds (2). 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 examples below.

The polymerizable liquid crystal composition of the present invention can greatly reduce the phase transition temperature by containing the polymerizable liquid crystal compound (1) and the polymerizable liquid crystal compound (2) in combination, compared to the case where the polymerizable liquid crystal compound (2) is used alone. For example, the phase transition temperature of the liquid crystal mixture of the polymerizable liquid crystal compound (1) and the polymerizable liquid crystal compound (2) constituting the polymerizable liquid crystal composition of the present invention is preferably 153° C. or less, more preferably 150° C. or less, and even more preferably 145° C. or less. In addition, when the polymerizable liquid crystal compound (1) of the present invention is used in combination with the polymerizable liquid crystal compound (2), the phase transition temperature can be reduced by preferably 8° C. or more, more preferably 10° C. or more, even more preferably 12° C. or more, and particularly preferably 15° C. or more, compared to the case where the polymerizable liquid crystal compound (2) is used alone.
In the present invention, the phase transition temperature of the polymerizable liquid crystal compound can be measured by the method described in the Examples below. When two or more polymerizable liquid crystal compounds are contained, the phase transition temperature is measured using a polymerizable liquid crystal compound (mixture) having the same composition as the polymerizable liquid crystal compound constituting the polymerizable liquid crystal composition.

Furthermore, the polymerizable liquid crystal composition of the present invention contains a combination of polymerizable liquid crystal compound (1) and polymerizable liquid crystal compound (2), and is therefore superior in terms of increasing the solubility of the polymerizable liquid crystal compound in a solvent, compared to the case where polymerizable liquid crystal compound (2) is used alone.

The method for producing the polymerizable liquid crystal compound (1) and the polymerizable liquid crystal compound (2) constituting the polymerizable liquid crystal composition of the present invention is not particularly limited, and each of them can be produced by appropriately combining known organic synthesis reactions (e.g., condensation reaction, esterification reaction, Williamson reaction, Ullmann reaction, Wittig reaction, Schiff base formation reaction, benzylation reaction, Sonogashira reaction, Suzuki-Miyaura reaction, Negishi reaction, Kumada reaction, Hiyama reaction, Buchwald-Hartwig reaction, Friedel-Crafts reaction, Heck reaction, aldol reaction, etc.) described in Methoden der Organischen Chemie, Organic Reactions, Organic Syntheses, Comprehensive Organic Synthesis, New Experimental Chemistry Course, etc., according to their structures.

For example, a polymerizable liquid crystal compound (1) in which A ¹¹ and A ¹² , B ¹¹ and B ¹² , E ¹¹ and E ¹² , F ¹¹ and F ¹² , G ¹¹ and G ¹² , P ¹¹ and P ¹² , and Ar ¹¹ and Ar ¹² in formula (1) are each the same can be produced by subjecting a compound represented by formula (1-1) (hereinafter also referred to as "compound (1-1)"), a compound represented by formula (1-2) (hereinafter also referred to as "compound (1-2)"), and a compound represented by formula (1-3) (hereinafter also referred to as "compound (1-3)"). In addition, P, F, B, A, E and G in formula (1-1) are the same as those defined as P ¹¹ and P ¹² , F ¹¹ and F ¹² , B ¹¹ and B ¹² , A ¹¹ and A ¹² , E ¹¹ and E ¹² , and G ¹¹ and G ¹² in formula (1), respectively. Furthermore, M in formula (1-2) and Ar in formula (1-3) are the same as those defined as M, Ar ¹¹ , and Ar ¹² in formula (1), respectively. P, F, B, A, E, G and Ar are determined depending on the desired polymerizable liquid crystal compound (1) and polymerizable liquid crystal compound (2).

The reaction of the compounds (1-1) to (1-3) is preferably carried out in the presence of a condensing agent.
Examples of the condensing agent include 1-cyclohexyl-3-(2-morpholinoethyl)carbodiimide metho-para-toluenesulfonate, dicyclohexylcarbodiimide, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (some of which are commercially available as water-soluble carbodiimide: WSC), bis(2,6-diisopropylphenyl)carbodiimide, bis(trimethylsilyl)carbodiimide, carbodiimides such as N,N'-diisopropylcarbodiimide, 2-methyl-6-nitrobenzoic anhydride, 2,2'-carbonylbis-1H-imidazole, 1,1'-oxalyldiimidazole, diphenylphosphoryl azide, 1-(4-nitrobenzenesulfonyl)-1H-1,2,4-triazole, 1H-benzotriazol-1-yloxytripyrrolidinophosphonium hexafluorophosphate, 1 H-benzotriazol-1-yloxytris(dimethylamino)phosphonium hexafluorophosphate, N,N,N',N'-tetramethyl-O-(N-succinimidyl)uronium tetrafluoroborate, N-(1,2,2,2-tetrachloroethoxycarbonyloxy)succinimide, N-carbobenzoxysuccinimide, O-(6-chlorobenzotriazol-1-yl)-N,N,N',N'-tetramethyluronium tetrafluoroborate fluoroborate, O-(6-chlorobenzotriazol-1-yl)-N,N,N',N'-tetramethyluronium hexafluorophosphate, 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 para-toluenesulfonate, 2-fluoro-1-methylpyridinium para-toluenesulfonate, trichloroacetic acid pentachlorophenyl ester, and the like.
In terms of reactivity, cost, and the wide range of solvents available, preferred condensing agents are dicyclohexylcarbodiimide, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride, bis(2,6-diisopropylphenyl)carbodiimide, bis(trimethylsilyl)carbodiimide, N,N'-diisopropylcarbodiimide, and 2,2'-carbonylbis-1H-imidazole.

The polymerizable liquid crystal compound (2) can be produced, for example, by reacting the compound (1-1) with the compound (1-3).

In the present invention, the polymerizable liquid crystal compound (1) and the polymerizable liquid crystal compound (2) constituting the polymerizable liquid crystal composition may be prepared separately and then mixed to be used as a liquid crystal mixture. Alternatively, the polymerizable liquid crystal compound (1) and the polymerizable liquid crystal compound (2) can be obtained as a liquid crystal mixture by reacting the compounds (1-1) to (1-3) in an appropriate ratio. Without isolating each polymerizable liquid crystal compound from the obtained liquid crystal mixture, the liquid crystal mixture can be mixed with the polymerizable liquid crystal compound (1) or with the polymerizable liquid crystal compound (2) as necessary, thereby controlling the contents of the polymerizable liquid crystal compound (1) and the polymerizable liquid crystal compound (2) in the liquid crystal mixture, thereby preparing a desired polymerizable liquid crystal mixture.
When the polymerizable liquid crystal mixture is prepared by the former method, the contents of the polymerizable liquid crystal compounds (1) and (2) can be easily adjusted to a desired range, and the solvent solubility of the polymerizable liquid crystal compounds can be easily controlled. On the other hand, when the polymerizable liquid crystal mixture is prepared by the latter method, the synthesis is simple, and the polymerizable liquid crystal composition can be produced more efficiently.

When preparing a liquid crystal mixture of the polymerizable liquid crystal compound (1) and the polymerizable liquid crystal compound (2), the amount of the compound (1-2) used in the reaction is preferably 0.01 parts by mass or more and 30 parts by mass or less, and more preferably 0.1 parts by mass or more and 20 parts by mass or less, relative to 100 parts by mass of the compound (1-1). The amount of the compound (1-3) used in the reaction is preferably 1 part by mass or more and 70 parts by mass or less, and more preferably 10 parts by mass or more and 65 parts by mass or less, relative to 100 parts by mass of the compound (1-1). By adjusting the amounts of the compounds (1-1), (1-2) and (1-3) within the above ranges, it is easy to prepare a liquid crystal mixture containing the polymerizable liquid crystal compound (1) and the polymerizable liquid crystal compound (2) in the desired ratio.

The polymerizable liquid crystal composition of the present invention may contain a polymerizable liquid crystal compound other than the polymerizable liquid crystal compound (1) and the polymerizable liquid crystal compound (2) as long as it does not affect the effects of the present invention. Examples of such polymerizable liquid crystal compounds include compounds described in 3.2 Nonchiral rod-shaped liquid crystal molecules and 3.3 Chiral rod-shaped liquid crystal molecules in Chapter 3 Molecular structure and liquid crystal properties of Liquid Crystal Handbook (edited by Liquid Crystal Handbook Editorial Committee, published by Maruzen Co., Ltd. on October 30, 2000), compounds described in JP-A-2010-31223, and polymerizable liquid crystal compounds that can exhibit reverse wavelength dispersion when made into a liquid crystal cured film and polymerizable liquid crystal compounds that can exhibit normal wavelength dispersion, as described in JP-A-2011-207765, JP Patent No. 5962760, etc.

When the polymerizable liquid crystal composition of the present invention contains a polymerizable liquid crystal compound other than the polymerizable liquid crystal compound (1) and the polymerizable liquid crystal compound (2), the content thereof is preferably 20 parts by mass or less, more preferably 10 parts by mass or less, and even more preferably 5 parts by mass or less, relative to 100 parts by mass in total of the polymerizable liquid crystal compound (1) and the polymerizable liquid crystal compound (2). In particular, if the content of a liquid crystal compound having a molecular structure significantly different from that of the polymerizable liquid crystal compound (1) or the polymerizable liquid crystal compound (2) becomes too large, phase separation may occur, which may impair the appearance. Therefore, it is preferable that the polymerizable liquid crystal compound constituting the polymerizable liquid crystal composition of the present invention is substantially composed of a polymerizable liquid crystal compound having a structure similar to that of the polymerizable liquid crystal compound (1). The term "similar" refers to a structure common to, for example, the portions represented by -O-CO-G ¹¹ -E ¹¹ -(A ¹¹ -B ¹¹ ) _k11 -F ¹¹ -P ¹¹ and -O-CO-G ¹² -E ¹² -(A ¹² -B ¹² ) _k12 -F ¹² -P ¹² of the polymerizable liquid crystal compound (1) and the portions represented by Ar ¹¹ or Ar ¹² , and the term "substantially constituted" refers to the content of the polymerizable liquid crystal compound (1) and the polymerizable liquid crystal compound (2) being 90 mass % or more with respect to the total mass of the polymerizable liquid crystal compounds contained in the polymerizable liquid crystal composition of the present invention. In one embodiment of the present invention, the polymerizable liquid crystal composition does not contain any polymerizable liquid crystal compound other than the polymerizable liquid crystal compound (1) and the polymerizable liquid crystal compound (2).

The content of the polymerizable liquid crystal compound in the polymerizable liquid crystal composition of the present invention (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 even more preferably 90 to 95 parts by mass, based on 100 parts by mass of the solid content of the polymerizable liquid crystal composition. If the total mass of the polymerizable liquid crystal compounds is within the above range, it is advantageous in terms of the alignment of the resulting liquid crystal cured film. In this specification, the polymerizable liquid crystal compound includes polymerizable liquid crystal compound (1), polymerizable liquid crystal compound (2), and other polymerizable liquid crystal compounds different from these, if included (hereinafter, these are collectively referred to as "polymerizable liquid crystal mixture"). The solid content of the polymerizable liquid crystal composition means all components excluding volatile components such as organic solvents from the polymerizable liquid crystal composition.

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

In the present invention, the polymerizable liquid crystal mixture is preferably applied to a substrate or the like in a state of being dissolved in a solvent, so that the mixture preferably contains a solvent. The solvent is preferably a solvent capable of dissolving polymerizable liquid crystal compounds such as polymerizable liquid crystal compound (1) and polymerizable liquid crystal compound (2), and is preferably a solvent inactive to the polymerization reaction of the polymerizable liquid crystal compound. The polymerizable liquid crystal composition of the present invention contains a combination of polymerizable liquid crystal compound (1) and polymerizable liquid crystal compound (2), and thus the solvent solubility of polymerizable liquid crystal compound (2) can be significantly improved compared to the case where polymerizable liquid crystal compound (2) is dissolved alone in a solvent. Therefore, various solvents can be applied. Examples of the solvent include alcohol solvents such as water, methanol, ethanol, ethylene glycol, isopropyl alcohol, 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; ketone solvents such as acetone, methyl ethyl ketone, cyclopentanone, cyclohexanone, 2-heptanone, and methyl isobutyl ketone; aliphatic hydrocarbon solvents such as pentane, hexane, and heptane; alicyclic 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; and amide solvents such as dimethylacetamide, dimethylformamide, N-methyl-2-pyrrolidone (NMP), and 1,3-dimethyl-2-imidazolidinone. These solvents can be used alone or in combination of two or more. Among these, organic solvents are preferred, and alcohol solvents, ester solvents, ketone solvents, chlorine-containing solvents, amide solvents and aromatic hydrocarbon solvents are more preferred, and from the viewpoint of productivity, at least one selected from the group consisting of methyl ethyl ketone, methyl isobutyl ketone, cyclopentanone, cyclohexanone and N-methylpyrrolidone is even more preferred.

The content of the solvent in the polymerizable liquid crystal composition is preferably 50 to 98 parts by mass, more preferably 50 to 95 parts by mass, relative to 100 parts by mass of the polymerizable liquid crystal composition. Therefore, the solid content in 100 parts by mass of the polymerizable liquid crystal composition is preferably 2 to 50 parts by mass, more preferably 5 to 50 parts by mass. If the solid content is 50 parts by mass or less, the viscosity of the polymerizable liquid crystal composition is low, so that the thickness of the film tends to be approximately uniform and unevenness is unlikely to occur. The solid content can be appropriately determined in consideration of the thickness of the liquid crystal cured film to be produced. The polymerizable liquid crystal composition of the present invention is advantageous in that it has excellent solubility in solvents by containing a combination of the polymerizable liquid crystal compound (1) and the polymerizable liquid crystal compound (2), and therefore the amount of organic solvent used during coating and storage can be reduced.

The polymerizable liquid crystal composition of the present invention preferably contains a photopolymerization initiator. The photopolymerization initiator is a compound that generates reactive species by the contribution of light and can initiate a polymerization reaction of the polymerizable liquid crystal or the like. Examples of reactive species include active species such as radicals, cations, and anions. Among them, from the viewpoint of ease of reaction control, a photopolymerization initiator that generates radicals by light irradiation is preferred. As the photopolymerization initiator, only one type may be used, or two or more types may be used in combination.

Examples of the photopolymerization initiator include benzoin compounds, benzophenone compounds, benzyl ketal compounds, alkylphenone compounds, acylphosphine oxide compounds, α-hydroxyketone compounds, α-aminoketone compounds, triazine compounds, iodonium salts, and sulfonium salts. Specific examples include Irgacure (registered trademark) 907, Irgacure 184, Irgacure 651, Irgacure 819, Irgacure 250, Irgacure 369, Irgacure 379, Irgacure 127, Irgacure 2959, Irgacure 754, and Irgacure 379EG (all manufactured by BASF Japan Ltd.), Seikuol BZ, Seikuol Z, and Seikuol BEE (all manufactured by Seiko Chemical Co., Ltd.), and Kayacure (registered trademark). Examples of suitable urea include 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 ARCLES NCI-831, ADEKA ARCLES NCI-930 (all manufactured by ADEKA Corporation), TAZ-A, TAZ-PP (all manufactured by Nippon SiberHegner AG) and TAZ-104 (manufactured by Sanwa Chemical Co., Ltd.).
In the present invention, the polymerizable liquid crystal mixture composition preferably contains at least one type of photopolymerization initiator, and may contain two or more types of photopolymerization initiators.

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

Examples of α-acetophenone compounds include 2-methyl-2-morpholino-1-(4-methylsulfanylphenyl)propan-1-one, 2-dimethylamino-1-(4-morpholinophenyl)-2-benzylbutan-1-one, and 2-dimethylamino-1-(4-morpholinophenyl)-2-(4-methylphenylmethyl)butan-1-one, and more preferably 2-methyl-2-morpholino-1-(4-methylsulfanylphenyl)propan-1-one and 2-dimethylamino-1-(4-morpholinophenyl)-2-benzylbutan-1-one. Commercially available α-acetophenone compounds include Irgacure 369, 379EG, and 907 (all manufactured by BASF Japan Ltd.) and Seikuol BEE (manufactured by Seiko Chemical Co., Ltd.).

Oxime-based photopolymerization initiators generate methyl radicals when irradiated with light. This methyl radical allows the polymerization of the polymerizable liquid crystal compound in the depth of the liquid crystal cured film to proceed favorably. In addition, from the viewpoint of more efficiently progressing the polymerization reaction in the depth of the liquid crystal cured film to be formed, it is preferable to use a photopolymerization initiator that can efficiently use ultraviolet light with a wavelength of 350 nm or more. As photopolymerization initiators that can efficiently use ultraviolet light with a wavelength of 350 nm or more, triazine 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 oxime ester type carbazole compounds include 1,2-octanedione, 1-[4-(phenylthio)-2-(O-benzoyloxime)], ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-1-(O-acetyloxime), and the like. Commercially available oxime ester carbazole compounds include Irgacure OXE-01, Irgacure OXE-02, Irgacure OXE-03 (all manufactured by BASF Japan Ltd.), Adeka Optomer N-1919, Adeka Arcles NCI-831 (all manufactured by ADEKA Corporation), etc.

The amount of photopolymerization initiator added is usually 0.1 to 30 parts by weight, preferably 0.5 to 20 parts by weight, and more preferably 1 to 15 parts by weight, per 100 parts by weight of the polymerizable liquid crystal compound. Within the above range, the reaction of the polymerizable group proceeds sufficiently, and the orientation of the polymerizable liquid crystal compound is unlikely to be disturbed.

The use of a sensitizer can increase the sensitivity of the photopolymerization initiator. Examples of photosensitizers include xanthones such as xanthone and thioxanthone; anthracenes having substituents such as anthracene and alkyl ether; phenothiazine; and rubrene. Examples of photosensitizers include xanthones such as xanthone and thioxanthone; anthracenes having substituents such as anthracene and alkyl ether; phenothiazine; and rubrene. The content of the photosensitizer is usually 0.01 to 10 parts by mass, preferably 0.05 to 5 parts by mass, and more preferably 0.1 to 3 parts by mass, based on 100 parts by mass of the total amount of the polymerizable liquid crystal compound.

By adding a polymerization inhibitor, the polymerization reaction of the polymerizable liquid crystal compound can be controlled. Examples of the polymerization inhibitor include hydroquinones having a substituent such as hydroquinone and alkyl ether; catechols having a substituent such as alkyl ether, such as butylcatechol; radical scavengers such as pyrogallols and 2,2,6,6-tetramethyl-1-piperidinyloxy radical; thiophenols; β-naphthylamines and β-naphthols. In order to polymerize the polymerizable liquid crystal compound (1) without disturbing the orientation, the content of the polymerization inhibitor is usually 0.01 to 10 parts by mass, preferably 0.1 to 5 parts by mass, and more preferably 0.1 to 3 parts by mass, based on 100 parts by mass of the total amount of the polymerizable liquid crystal compound.

Furthermore, the polymerizable liquid crystal composition of the present invention may contain a leveling agent. The leveling agent is an additive that adjusts the fluidity of the polymerizable liquid crystal composition and functions to make the film obtained by applying the composition flatter. Examples of the leveling agent include silicone-based, polyacrylate-based, and perfluoroalkyl-based leveling agents. Specifically, DC3PA, SH7PA, DC11PA, SH28PA, SH29PA, SH30PA, ST80PA, ST86PA, SH8400, SH8700, FZ2123 (all manufactured by Dow Corning Toray 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 Momentive Performance Materials, Inc.) Japan LLC), Fluorinert (registered trademark) FC-72, FC-40, FC-43, FC-3283 (all manufactured by Sumitomo 3M Limited), Megafac (registered trademark) R-08, R-30, R-90, F-410, F-411, F-443, F-445, F-470, F-477, F-479, F-482, F-483 (all manufactured by DIC Corporation), F-top (trade name) EF301, EF303, EF351, EF352 (all manufactured by Mitsubishi Materials Electronics Co., Ltd.), Surflon (registered trademark) S-381, S-382, S-383, S-393, SC-101, SC-105, KH-40, SA-100 (all manufactured by AGC Seimi Chemical Co., Ltd.), trade names E1830, E5844 (manufactured by Daikin Fine Chemical Research Institute 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, based on 100 parts by mass of the total amount of the polymerizable liquid crystal compound. When 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 be smoother, which is preferable. The polymerizable liquid crystal composition may contain two or more types of leveling agents.

The polymerizable liquid crystal composition of the present invention can be prepared by adding additives such as a solvent, a photopolymerization initiator, a polymerization inhibitor, a photosensitizer, or a leveling agent to the polymerizable liquid crystal compound (1) and the polymerizable liquid crystal compound (2) as necessary, and stirring and mixing them at a predetermined temperature.

<Retardation film>
The polymerizable liquid crystal composition of the present invention has a low phase transition temperature of the polymerizable liquid crystal compound, and can produce a liquid crystal cured film at a lower processing temperature, so that the influence of heating can be reduced to obtain a liquid crystal cured film with excellent optical properties. In addition, since the composition has high solubility in a solvent and excellent coatability and film-forming properties, the occurrence of alignment defects due to undissolved polymerizable liquid crystal compounds and precipitates and deposits in the composition can be suppressed. 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 cured product of the polymerizable liquid crystal composition of the present invention, in particular, a retardation film comprising a liquid crystal cured film obtained by curing the polymerizable liquid crystal composition in a state in which the polymerizable liquid crystal compound (1) and the polymerizable liquid crystal compound (2) in the polymerizable liquid crystal composition are aligned. The retardation film composed of the liquid crystal cured film can fully exhibit the optical properties that the polymerizable liquid crystal compound used can originally exhibit, and can be a retardation film with high optical performance.

The liquid crystal cured film constituting the retardation film of the present invention may be composed of a homopolymer of polymerizable liquid crystal compound (1) in an oriented state and a homopolymer of polymerizable liquid crystal compound (2), or may be composed of a copolymer of a mixture of polymerizable liquid crystal compound (1) and polymerizable liquid crystal compound (2) in an oriented state. Since the polymerization reaction is easy and a uniform liquid crystal cured film is easily obtained, it is preferable that the liquid crystal cured film constituting the retardation film of the present invention is composed of a copolymer of a mixture of polymerizable liquid crystal compound (1) and polymerizable liquid crystal compound (2) in an oriented state.

In one embodiment of the present invention, the retardation film of the present invention is a cured product of the polymerizable liquid crystal composition of the present invention, and includes a liquid crystal cured film having optical properties represented by the following formulas (i), (ii), and (iii). The liquid crystal cured film is usually a cured product obtained by curing a polymerizable liquid crystal compound in a state where the polymerizable liquid crystal compound is aligned in the horizontal direction relative to the plane of the liquid crystal cured film (hereinafter, also referred to as a "horizontally aligned liquid crystal cured film").
Re(450)/Re(550)≦1.00 (i)
1.00≦Re(650)/Re(550) (ii)
100nm≦Re(550)≦180nm (iii)
[In the formula, Re(λ) represents an in-plane retardation value of the cured liquid crystal film at a wavelength of λ nm, and Re=(nx(λ)-ny(λ))×d (d represents a thickness of the cured liquid crystal film, nx represents a principal refractive index at a wavelength of λ nm in a direction parallel to the plane of the cured liquid crystal film in an index ellipsoid formed by the cured liquid crystal film, and ny represents a refractive index at a wavelength of λ nm in a direction parallel to the plane of the cured liquid crystal film and perpendicular to the direction of nx in an index ellipsoid formed by the cured liquid crystal film).]

When the horizontally aligned liquid crystal cured film satisfies the formulas (i) and (ii), the horizontally aligned liquid crystal cured film exhibits so-called reverse wavelength dispersion, in which the in-plane retardation value at a short wavelength is smaller than the in-plane retardation value at a long wavelength. Since the reverse wavelength dispersion is improved and the optical properties of the retardation film are further improved, Re(450)/Re(550) is preferably 0.70 or more, more preferably 0.78 or more, and also preferably 0.90 or less, more preferably 0.88 or less, even more preferably 0.86 or less, particularly preferably 0.85 or less, and especially preferably 0.84 or less. In addition, Re(650)/Re(550) is preferably 1.00 or more, more preferably 1.01 or more, and even more preferably 1.02 or more.

The above in-plane retardation value can be adjusted by the thickness d of the horizontally aligned liquid crystal cured film. Since the in-plane retardation value is determined by the above formula Re(λ) = (nx(λ) - ny(λ)) x d, the desired in-plane retardation value (Re(λ): in-plane retardation value of the horizontally aligned liquid crystal cured film at wavelength λ (nm)) can be obtained by adjusting the three-dimensional refractive index and film thickness d.

In addition, when the horizontally aligned liquid crystal cured film satisfies formula (iii), the effect of improving the front reflection hue (effect of suppressing coloration) is excellent when an elliptical polarizing plate having a retardation film containing the horizontally aligned liquid crystal cured film is applied to an organic EL display device. A more preferable range of the in-plane retardation value is 120 nm ≦ Re(550) ≦ 170 nm, and an even more preferable range is 130 nm ≦ Re(550) ≦ 150 nm.

In one embodiment of the present invention, the retardation film of the present invention is a cured product of the polymerizable liquid crystal composition of the present invention, and includes a liquid crystal cured film having optical properties represented by the following formulas (iv), (v) and (vi). The liquid crystal cured film is usually a cured product obtained by curing a polymerizable liquid crystal compound in a state where the polymerizable liquid crystal compound is aligned in a direction perpendicular to the plane of the liquid crystal cured film (hereinafter, also referred to as a "vertically aligned liquid crystal cured film").
Rth(450)/Rth(550)≦1.00 (iv)
1.00≦Rth(650)/Rth(550) (v)
-100nm≦Rth(550)≦-40nm (vi)
[In the formula, Rth(λ) represents a retardation value in the thickness direction of the cured liquid crystal film at a wavelength of λ nm, and Rth=((nx(λ)+ny(λ))/2-nz)×d (d represents the thickness of the cured liquid crystal film, nx represents the principal refractive index at a wavelength of λ nm in a direction parallel to the plane of the cured liquid crystal film in the index ellipsoid formed by the cured liquid crystal film, ny represents the refractive index at a wavelength of λ nm in a direction parallel to the plane of the cured liquid crystal film and perpendicular to the direction of nx in the index ellipsoid formed by the cured liquid crystal film, and nz represents the refractive index at a wavelength of λ nm in a direction perpendicular to the plane of the cured liquid crystal film in the index ellipsoid formed by the cured liquid crystal film).]

When the vertically aligned liquid crystal cured film satisfies the formulas (iv) and (v), in an elliptical polarizing plate having a retardation film including the vertically aligned liquid crystal cured film, the decrease in ellipticity on the short wavelength side can be suppressed, and the oblique reflection hue can be improved. The value of Rth(450)/Rth(550) in the vertically aligned liquid crystal cured film is preferably 0.70 or more, more preferably 0.78 or more, and also preferably 0.90 or less, more preferably 0.88 or less, even more preferably 0.86 or less, particularly preferably 0.85 or less, and especially preferably 0.84 or less. In addition, Rth(650)/Rth(550) is preferably 1.0 or more, more preferably 1.01 or more, and even more preferably 1.02 or more.

In addition, when the vertically aligned liquid crystal cured film satisfies formula (vi), the oblique reflection hue can be improved when an elliptical polarizing plate having a retardation film containing the vertically aligned liquid crystal cured film is applied to an organic EL display device. The retardation value Rth(550) in the thickness direction of the vertically aligned liquid crystal cured film is more preferably -90 nm or more, even more preferably -80 nm or more, and more preferably -50 nm or less.

The retardation film of the present invention is, for example,
A step of 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
The liquid crystal layer can be produced by a method including a step of polymerizing a polymerizable liquid crystal compound by light irradiation while maintaining the aligned state to form a liquid crystal cured film.

The coating film of the polymerizable liquid crystal composition can be formed by applying the polymerizable liquid crystal composition onto a substrate or onto an alignment film described below.
Examples of the substrate include glass substrates and film substrates, but resin film substrates are preferred from the viewpoint of processability. Examples of the resin constituting the film substrate include polyolefins such as polyethylene, polypropylene, and norbornene-based polymers; cyclic olefin resins; polyvinyl alcohol; polyethylene terephthalate; polymethacrylic acid esters; polyacrylic acid esters; cellulose esters such as triacetyl cellulose, diacetyl cellulose, and cellulose acetate propionate; polyethylene naphthalate; polycarbonate; polysulfone; polyether sulfone; polyether ketone; plastics such as polyphenylene sulfide and polyphenylene oxide. Such resins can be formed into a film by known means such as solvent casting and melt extrusion to form the substrate. The substrate surface may have a protective layer formed from an acrylic resin, a methacrylic resin, an epoxy resin, an oxetane resin, a urethane resin, a melamine resin, or the like, and may be subjected to a surface treatment such as a release treatment such as silicone treatment, a corona treatment, or a plasma treatment.

Commercially available products may be used as the substrate. Examples of commercially available cellulose ester substrates include cellulose ester substrates manufactured by Fuji Photo Film Co., Ltd., such as Fujitac Film; cellulose ester substrates manufactured by Konica Minolta Opto Co., Ltd., such as "KC8UX2M", "KC8UY", and "KC4UY". Examples of commercially available cyclic olefin resins include cyclic olefin resins manufactured by Ticona (Germany), such as "Topas (registered trademark)", cyclic olefin resins manufactured by JSR Corporation, such as "Arton (registered trademark)", cyclic olefin resins manufactured by Zeon Corporation, such as "ZEONOR (registered trademark)" and "ZEONEX (registered trademark)", and cyclic olefin resins manufactured by Mitsui Chemicals, Inc., such as "Apel" (registered trademark). Commercially available cyclic olefin resin substrates may also be used. Commercially available cyclic olefin resin substrates include cyclic olefin resin substrates manufactured by Sekisui Chemical Co., Ltd., such as "S-Cina (registered trademark)" and "SCA40 (registered trademark)"; cyclic olefin resin substrates manufactured by Optes Co., Ltd., such as "ZEONORFILM (registered trademark)"; and cyclic olefin resin substrates manufactured by JSR Corporation, such as "ARTONFILM (registered trademark)."

From the viewpoints of making the retardation film thinner, making the substrate easier to peel off, and making the substrate easier to handle, the thickness of the substrate is usually 5 to 300 μm, and preferably 10 to 150 μm.

Methods for applying the polymerizable liquid crystal composition to a substrate or the like include known methods such as application methods such as spin coating, extrusion, gravure coating, die coating, bar coating, and applicator methods, and printing methods such as flexography.

Then, the solvent is removed by drying or the like to form a dried coating film. Examples of drying methods include natural drying, ventilation drying, heat drying, and reduced pressure drying. At this time, by heating the coating film obtained from the polymerizable liquid crystal composition, the solvent can be dried and removed from the coating film, and the polymerizable liquid crystal compound can be aligned in a desired direction (for example, horizontal or vertical) relative to the coating film plane. The heating temperature of the coating film can be appropriately determined taking into consideration the materials of the polymerizable liquid crystal compound used and the substrate on which the coating film is formed, etc., but in order to phase-transition the polymerizable liquid crystal compound to a liquid crystal phase state, it is usually necessary for the temperature to be equal to or higher than the liquid crystal phase transition temperature. In order to bring the polymerizable liquid crystal compound into a desired alignment state while removing the solvent contained in the polymerizable liquid crystal composition, it can be heated, for example, to a temperature equal to or higher than the liquid crystal phase transition temperature (smectic phase transition temperature or nematic phase transition temperature) of the polymerizable liquid crystal compound contained in the polymerizable liquid crystal composition.

The polymerizable liquid crystal composition of the present invention contains a polymerizable liquid crystal compound (1) and a polymerizable liquid crystal compound (2), and can usually undergo liquid crystal phase transition at a temperature lower than the temperature at which each of the polymerizable liquid crystal compound (1) and the polymerizable liquid crystal compound (2) transitions to a liquid crystal phase. In one embodiment of the present invention, the solid-liquid crystal phase transition temperature of the polymerizable liquid crystal mixture constituting the polymerizable liquid crystal composition of the present invention is preferably 25° C. or higher and 153° C. or lower. When the phase transition temperature to the liquid crystal phase is within the above range, a liquid crystal cured film can be produced at a lower processing temperature, and a liquid crystal cured film having high optical properties that the polymerizable liquid crystal compound can inherently exhibit can be obtained while suppressing deterioration of optical properties due to heating. In addition, in the production of a retardation 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. Furthermore, since the liquid crystal phase transition can be performed by heating at a relatively low temperature, there is also an advantage that the options for the support substrate to which the polymerizable liquid crystal composition is applied are expanded. In the present invention, the solid-liquid crystal phase transition temperature of the polymerizable liquid crystal mixture is usually 40° C. or higher, more preferably 50° C. or higher, and even more preferably 60° C. or higher, from the viewpoint of enabling the resulting liquid crystal cured film to exhibit reverse wavelength dispersion characteristics, and is more preferably 150° C. or lower, even more preferably 145° C. or lower, and particularly preferably 144° C. or lower, from the viewpoint of achieving more significant effects of the present invention.
The liquid crystal phase transition temperature can be measured, for example, using a polarizing microscope equipped with a temperature control stage, a differential scanning calorimeter (DSC), a thermogravimetric differential thermal analyzer (TG-DTA), etc. The phase transition temperature in the polymerizable liquid crystal mixture of the present invention containing at least two polymerizable liquid crystal compounds means a temperature measured using a mixture of polymerizable liquid crystal compounds in which all polymerizable liquid crystal compounds constituting the polymerizable liquid crystal mixture are mixed in the same ratio as the composition in the polymerizable liquid crystal mixture.

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

The removal of the solvent from the coating film may be performed simultaneously with heating to a temperature equal to or higher than the liquid crystal phase transition temperature of the polymerizable liquid crystal compound, or may be performed separately, but it is preferable to perform the removal simultaneously from the viewpoint of improving productivity. Before heating to a temperature equal to or higher than the liquid crystal phase transition temperature of the polymerizable liquid crystal compound, a preliminary drying step may be provided to adequately remove the solvent in the coating film obtained from the polymerizable liquid crystal composition under conditions in which the polymerizable liquid crystal compound contained in the coating film does not polymerize. Examples of the drying method in the preliminary drying step include natural drying, ventilation drying, heat drying, and reduced pressure drying, and the drying temperature (heating temperature) in the drying step can be appropriately determined depending on the type of polymerizable liquid crystal compound used, the type of solvent, its boiling point, and its amount, etc.

Next, in the obtained dried coating film, the polymerizable liquid crystal compound is polymerized by light irradiation while maintaining the orientation state of the polymerizable liquid crystal compound, thereby forming a liquid crystal cured film that is a polymer of the polymerizable liquid crystal compound existing in a desired orientation state. Since the polymerizable liquid crystal composition of the present invention can be highly polymerized by light irradiation such as high-intensity ultraviolet light while suppressing damage to the polymerizable liquid crystal compound, a photopolymerization method is usually used as a polymerization method. In photopolymerization, the light irradiated to the dried coating film is appropriately selected according to the type of polymerization initiator contained in the dried coating film, the type and amount of the polymerizable liquid crystal compound. Specific examples thereof include one or more types of light 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. Among them, ultraviolet light is preferred in terms of ease of controlling the progress of the polymerization reaction and the ability to use photopolymerization devices that are widely used in this field, and it is preferable to select the type of polymerizable liquid crystal compound and polymerization initiator contained in the polymerizable liquid crystal composition so that they can be photopolymerized by ultraviolet light. In addition, the polymerization temperature can be controlled by irradiating light while cooling the dried coating film with an appropriate cooling means during polymerization. By adopting such a cooling means, the polymerization of the polymerizable liquid crystal compound can be carried out at a lower temperature, and even if a substrate with relatively low heat resistance is used, a liquid crystal cured film can be appropriately formed. In addition, it is also possible to promote the polymerization reaction by increasing the polymerization temperature within a range where defects due to heat during light irradiation (such as deformation of the substrate due to heat) do not occur. During photopolymerization, a patterned cured film can also be obtained by performing masking and development, etc.

Examples of light sources for the active energy rays 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 lamps, gallium lamps, excimer lasers, LED light sources emitting light in the wavelength range of 380 to 440 nm, chemical lamps, black light lamps, microwave-excited mercury lamps, and metal halide lamps.

The ultraviolet irradiation intensity is usually 10 to 3,000 mW/ ^cm2 . The ultraviolet irradiation intensity is preferably an intensity in a wavelength region effective for activating a photopolymerization initiator. The time for irradiating light is usually 0.1 seconds to 10 minutes, preferably 0.1 seconds to 5 minutes, more preferably 0.1 seconds to 3 minutes, and even more preferably 0.1 seconds to 1 minute. When irradiating once or multiple times with such ultraviolet irradiation intensity, the integrated light amount is 10 to 3,000 mJ/ ^cm2 , preferably 50 to 2,000 mJ/ ^cm2 , and more preferably 100 to 1,000 mJ/ ^cm2 .

The thickness of the liquid crystal cured film can be appropriately selected depending on the display device to which it is applied, and is preferably 0.2 to 3 μm, and more preferably 0.2 to 2 μm.

The coating of the polymerizable liquid crystal composition may be formed on an alignment film. The alignment film has an alignment regulating force that aligns the polymerizable liquid crystal compound in a desired direction. For example, there is a horizontal alignment film that has an alignment regulating force that aligns the polymerizable liquid crystal compound in the horizontal direction, and a vertical alignment film that has an alignment regulating force that aligns the polymerizable liquid crystal compound in the vertical direction. The alignment regulating force can be adjusted arbitrarily by the type of alignment film, the surface state, the rubbing conditions, etc., and when the alignment film is formed from a photoalignable polymer, it can be adjusted arbitrarily by the polarized light irradiation conditions, etc.

As the alignment film, it is preferable that the film has solvent resistance so that the polymerizable liquid crystal composition does not dissolve when applied, and also has heat resistance during the heat treatment for removing the solvent and for orienting the polymerizable liquid crystal compound described below. Examples of the alignment film include an alignment film containing an alignment polymer, a photo-alignment film, a groove alignment film having a concave-convex pattern or multiple grooves on the surface, and a stretched film stretched in the alignment direction, and the like. From the viewpoint of the precision of the alignment angle and quality, a photo-alignment film is preferable.

Examples of oriented polymers include polyamides and gelatins having amide bonds in the molecule, polyimides having imide bonds in the molecule, and their hydrolyzates such as polyamic acid, polyvinyl alcohol, alkyl-modified polyvinyl alcohol, polyacrylamide, polyoxazole, polyethyleneimine, polystyrene, polyvinylpyrrolidone, polyacrylic acid, and polyacrylic acid esters. Of these, polyvinyl alcohol is preferred. Oriented polymers can be used alone or in combination of two or more.

An alignment film containing an alignment polymer is usually obtained by applying a composition in which an alignment polymer is dissolved in a solvent (hereinafter sometimes referred to as an "alignment polymer composition") to a substrate and removing the solvent, or by applying an alignment polymer composition to a substrate, removing the solvent, and rubbing (rubbing method). Examples of the solvent include the same solvents as those exemplified above as solvents that can be used in the polymerizable liquid crystal composition.

The concentration of the oriented polymer in the oriented polymer composition may be within a range in which the oriented polymer material can be completely dissolved in the solvent, but is preferably 0.1 to 20% in terms of solids content relative to the solution, and more preferably approximately 0.1 to 10%.

As the oriented polymer composition, commercially available alignment film materials may be used as they are. 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).

Methods for applying the alignable polymer composition to a substrate include the same methods as those exemplified as the methods for applying the polymerizable liquid crystal composition to a substrate.

Methods for removing the solvent contained in the oriented polymer composition include natural drying, ventilation drying, heat drying, and reduced pressure drying.

In order to impart an orientation control force to the orientation film, a rubbing treatment can be performed as necessary (rubbing method). One method for imparting an orientation control force by the rubbing method is to bring an orientation polymer film formed on the surface of a substrate by applying an orientation polymer composition to the substrate and annealing the composition into contact with a rotating rubbing roll wrapped with a rubbing cloth. If masking is performed during the rubbing treatment, multiple regions (patterns) with different orientation directions can also be formed in the orientation film.

Photo-alignment films are usually obtained by applying a composition containing 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). Photo-alignment films are also advantageous in that the direction of the alignment control force can be freely controlled by selecting the polarization direction of the polarized light to be irradiated.

The photoreactive group refers to a group that generates liquid crystal alignment ability when irradiated with light. Specific examples include groups involved in photoreactions that are the origin of liquid crystal alignment ability, such as molecular alignment induction caused by light irradiation, or isomerization reactions, dimerization reactions, photocrosslinking reactions, or photodecomposition reactions. Among these, groups involved in dimerization reactions or photocrosslinking reactions are preferred in terms of excellent alignment ability. As the photoreactive group, a group having an unsaturated bond, particularly a double bond, is preferred, and a group having at least one bond selected from the group consisting of a carbon-carbon double bond (C=C bond), a carbon-nitrogen double bond (C=N bond), a nitrogen-nitrogen double bond (N=N bond), and a carbon-oxygen double bond (C=O bond) is particularly preferred.

Examples of photoreactive groups having a C=C bond include vinyl groups, polyene groups, stilbene groups, stilbazole groups, stilbazolium groups, chalcone groups, and cinnamoyl 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 azobenzene groups, azonaphthalene groups, aromatic heterocyclic azo groups, bisazo groups, formazan groups, and groups having an azoxybenzene structure. Examples of photoreactive groups having a C=O bond include benzophenone groups, coumarin groups, anthraquinone groups, and maleimide groups. These groups may have substituents such as alkyl groups, alkoxy groups, aryl groups, allyloxy groups, cyano groups, alkoxycarbonyl groups, hydroxyl groups, sulfonic acid groups, and halogenated alkyl groups.

Among these, photoreactive groups involved in photodimerization reactions are preferred, and cinnamoyl and chalcone groups are preferred because they require a relatively small amount of polarized light irradiation for photoalignment and are easy to obtain photoalignment films with excellent thermal and temporal stability. As polymers having photoreactive groups, those having cinnamoyl groups such that the terminals of the polymer side chains form cinnamic acid structures are particularly preferred.

By applying the composition for forming a photo-alignment film onto a substrate, a photo-alignment-inducing layer can be formed on the substrate. Examples of the solvent contained in the composition include the same solvents as those exemplified above as solvents that can be used in the polymerizable liquid crystal composition, and can be appropriately selected depending on the solubility of the polymer or monomer having a photoreactive group.

The content of the polymer or monomer having a photoreactive group in the composition for forming a photo-alignment film can be adjusted as appropriate depending on the type of polymer or monomer and the desired thickness of the photo-alignment film, but is preferably at least 0.2% by mass, more preferably in the range of 0.3 to 10% by mass, relative to the mass of the composition for forming a photo-alignment film. The composition for forming a photo-alignment film may contain a polymer material such as polyvinyl alcohol or polyimide, or a photosensitizer, as long as the properties of the photo-alignment film are not significantly impaired.

Methods for applying the composition for forming a photo-alignment film to a substrate include the same methods as those for applying an alignable polymer composition to a substrate. Methods for removing the solvent from the applied composition for forming a photo-alignment film include, for example, natural drying, ventilation drying, heat drying, and reduced pressure drying.

To irradiate the polarized light, the polarized UV may be irradiated directly onto the composition for forming a photo-aligned film coated on the substrate from which the solvent has been removed, or the polarized light may be irradiated from the substrate side and then transmitted through the substrate. It is particularly preferable that the polarized light is substantially parallel light. The wavelength of the polarized light to be irradiated is preferably in a wavelength range in which the photoreactive group of the polymer or monomer having a photoreactive group can absorb light energy. Specifically, UV (ultraviolet light) in the wavelength range of 250 to 400 nm is particularly preferable. Examples of light sources used for the polarized light irradiation include xenon lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, metal halide lamps, and ultraviolet lasers such as KrF and ArF, with high-pressure mercury lamps, ultra-high-pressure mercury lamps, and metal halide lamps being more preferable. Among these, high-pressure mercury lamps, ultra-high-pressure mercury lamps, and metal halide lamps are preferable because they have a high emission intensity of ultraviolet light with a wavelength of 313 nm. Polarized UV can be irradiated by passing the light from the light source through an appropriate polarizer. Such polarizers can be polarizing filters, polarizing prisms such as Glan-Thompson and Glan-Taylor, or wire grid type polarizers.

If masking is performed when rubbing or irradiating with polarized light, multiple regions (patterns) with different liquid crystal alignment directions can be formed.

A groove alignment film is a film that has a concave-convex pattern or multiple grooves on its surface. When a polymerizable liquid crystal compound is applied to a film that has multiple equally spaced linear grooves, the liquid crystal molecules are oriented in the direction along the grooves.

Methods for obtaining a groove alignment film include a method in which the surface of a photosensitive polyimide film is exposed through an exposure mask having slits in the shape of a pattern, followed by development and rinsing to form a concave-convex pattern; a method in which a layer of uncured UV-cured resin is formed on a plate-shaped master having grooves on its surface, and the formed resin layer is transferred to a substrate and then cured; and a method in which a roll-shaped master having multiple grooves is pressed against an uncured UV-cured resin film formed on a substrate to form concave-convex patterns, followed by curing.

Furthermore, in addition to the above-mentioned orienting polymers, materials that exhibit an orientation control force that orients the polymerizable liquid crystal compound in a direction perpendicular to the plane of the liquid crystal cured film may also be used, such as fluorine-based polymers such as perfluoroalkyl, silane compounds, and polysiloxane compounds obtained by condensation reactions thereof.

When a silane compound is used as a material for forming the alignment film, a compound containing Si and C elements as constituent elements is preferable from the viewpoint of easily reducing surface tension and easily increasing adhesion with layers adjacent to the alignment film, and a silane compound can be preferably used. As the silane compound, a silane-containing ionic compound or the like can be used, and the vertical alignment control force can be increased by using such a silane compound. As the silane compound, one type may be used alone, two or more types may be used in combination, or it may be used in combination with other materials. When the silane compound is a non-ionic silane compound, a silane compound having an alkyl group at the molecular end is preferable from the viewpoint of easily increasing the vertical alignment control force, and a silane compound having an alkyl group with 3 to 30 carbon atoms is more preferable.

The thickness of the alignment film (alignment film containing an alignment polymer or photoalignment film) is usually in the range of 10 to 10,000 nm, preferably in the range of 10 to 1000 nm, more preferably 10 to 500 nm or less, even more preferably 10 to 300 nm, and particularly preferably 50 to 250 nm.

The present invention includes a polarizing plate (elliptical polarizing plate) including the retardation film of the present invention. The polarizing plate of the present invention usually includes the retardation film of the present invention and a polarizing film.
The polarizing film is a film having a polarizing function, and examples of the polarizing film include a stretched film having a dye having anisotropic absorption adsorbed thereon, a film coated with a dye having anisotropic absorption as a polarizer, etc. Examples of the dye having anisotropic absorption include a dichroic dye.

A film containing a stretched film adsorbed with a dye having absorption anisotropy as a polarizer is usually produced by uniaxially stretching a polyvinyl alcohol resin film, dyeing the polyvinyl alcohol resin film with a dichroic dye to adsorb the dichroic dye, treating the polyvinyl alcohol resin film with the adsorbed dichroic dye with an aqueous boric acid solution, and washing with water after the treatment with the aqueous boric acid solution, and then sandwiching at least one surface of the polarizer produced by this process between a transparent protective film via an adhesive.

Polyvinyl alcohol resins are obtained by saponifying polyvinyl acetate resins. Polyvinyl acetate resins include polyvinyl acetate, which is a homopolymer of vinyl acetate, as well as copolymers of vinyl acetate and other monomers that can be copolymerized with it. Examples of other monomers that can be copolymerized with vinyl acetate include unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, and acrylamides with ammonium groups.

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

A film made from such polyvinyl alcohol-based resin is used as the base film for the polarizing film. The method for making the polyvinyl alcohol-based resin into a film is not particularly limited, and the film can be made by a known method. The thickness of the polyvinyl alcohol-based base film can be, for example, about 10 to 150 μm.

The uniaxial stretching of the polyvinyl alcohol-based resin film can be performed before, simultaneously with, or after dyeing with a dichroic dye. When the uniaxial stretching is performed after dyeing, it may be performed before or during the boric acid treatment. It is also possible to perform the uniaxial stretching at these multiple stages. The uniaxial stretching may be performed uniaxially between rolls with different peripheral speeds, or may be performed uniaxially using a heated roll. The uniaxial stretching may be dry stretching in which the stretching is performed in the atmosphere, or wet stretching in which the polyvinyl alcohol-based resin film is stretched in a swollen state using a solvent. The stretching ratio is usually about 3 to 8 times.

Dyeing of a polyvinyl alcohol-based resin film with a dichroic dye is carried out, for example, by immersing the polyvinyl alcohol-based resin film in an aqueous solution containing the dichroic dye.

Specific examples of the dichroic pigment include iodine and dichroic organic dyes. Examples of the dichroic organic dye include dichroic direct dyes made of disazo compounds such as C.I. DIRECT RED 39, and dichroic direct dyes made of compounds such as trisazo and tetrakisazo. It is preferable to immerse the polyvinyl alcohol resin film in water before the dyeing process.

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

On the other hand, when a dichroic organic dye is used as the dichroic pigment, a method of dyeing a polyvinyl alcohol-based resin film by immersing it in an aqueous solution containing a water-soluble dichroic dye is usually adopted. The content of the dichroic organic dye in this aqueous solution is usually about 1×10 ⁻⁴ to 10 parts by mass, preferably 1×10 ⁻³ to 1 part by mass, and more preferably 1×10 ⁻³ to 1×10 ⁻² parts by mass per 100 parts by mass of water. This aqueous solution may contain an inorganic salt such as sodium sulfate as a dyeing assistant. The temperature of the dichroic dye aqueous solution used for dyeing is usually about 20 to 80° C. In addition, the immersion time in this aqueous solution (dyeing time) is usually about 10 to 1,800 seconds.

The boric acid treatment after dyeing with a dichroic dye can usually be carried out by immersing the dyed polyvinyl alcohol resin film in an aqueous boric acid solution. The content of boric acid in this aqueous boric acid solution is usually about 2 to 15 parts by mass, preferably 5 to 12 parts by mass, per 100 parts by mass of water. When iodine is used as the dichroic dye, this aqueous boric acid solution preferably contains potassium iodide, and in this case the content of potassium iodide is usually about 0.1 to 15 parts by mass, preferably 5 to 12 parts by mass, per 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 more preferably 200 to 400 seconds. The temperature for the boric acid treatment is usually 50°C or higher, preferably 50 to 85°C, and more preferably 60 to 80°C.

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

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

The thickness of the polarizer obtained by uniaxially stretching the polyvinyl alcohol resin film, dyeing it with a dichroic dye, treating it with boric acid, washing it with water and drying it is preferably 5 to 40 μm.

Examples of films coated with a dye having absorption anisotropy include films 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. The film preferably has a protective film on one or both sides. Examples of the protective film include the same resin films as those exemplified above as substrates that can be used in the production of liquid crystal cured films.

The film coated with the dye having absorption anisotropy is preferably thin, but if it is too thin, the strength decreases and the processability tends to be poor. 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 films coated with a dye having the above-mentioned absorption anisotropy include the films described in JP 2012-33249 A and the like.

The polarizing film may have a transparent protective film laminated on at least one surface of the polarizer thus obtained via an adhesive. As the transparent protective film, a transparent film similar to the resin film exemplified above as a substrate that can be used in the production of the liquid crystal cured film can be preferably used.

The polarizing plate of the present invention is composed of the retardation film of the present invention and a polarizing film. For example, the retardation film of the present invention and the polarizing film are laminated via an adhesive layer or a pressure-sensitive adhesive layer, etc., to obtain the elliptical polarizing plate of the present invention.

In one aspect of the present invention, when the retardation film of the present invention containing a horizontally aligned liquid crystal cured film is laminated with a polarizing film, it is preferable to laminate them so that the angle between the slow axis (optical axis) of the horizontally aligned liquid crystal cured film constituting the retardation film and the absorption axis of the polarizing film is 45±5°.

The polarizing plate of the present invention may have a configuration similar to that of a conventional elliptical polarizing plate, or a polarizing film and a retardation film. Examples of such configurations include an adhesive layer (sheet) for attaching the elliptical polarizing plate to a display element such as an organic EL, and a protective film used to protect the surface of the polarizing film or retardation film from scratches and dirt.

The polarizing plate of the present invention can be used in various display devices, particularly optical displays.
The display device is a device having a display element, and includes a light-emitting element or a light-emitting device as a light source. Examples of the display device include a liquid crystal display device, an organic electroluminescence (EL) display device, an inorganic electroluminescence (EL) display device, a touch panel display device, an electron emission display device (e.g., a field emission display device (FED), a surface field emission display device (SED)), an electronic paper (a display device using electronic ink or an electrophoretic element, a plasma display device, a projection display device (e.g., a display device having a grating light valve (GLV) display device, a digital micromirror device (DMD)), and a piezoelectric ceramic display. The liquid crystal display device includes any of a transmissive liquid crystal display device, a semi-transmissive liquid crystal display device, a reflective liquid crystal display device, a direct-view liquid crystal display device, and a projection liquid crystal display device. These display devices may be display devices that display two-dimensional images, or stereoscopic display devices that display three-dimensional images. In particular, the elliptical polarizing plate of the present invention can be suitably used for an organic electroluminescence (EL) display device and an inorganic electroluminescence (EL) display device. These display devices (optical displays) can exhibit good image display characteristics by being provided with the polarizing plate of the present invention, which has excellent optical properties.

The present invention will be explained in more detail below with reference to the following examples. In the examples, "%" and "parts" refer to mass % and mass parts, respectively, unless otherwise specified.

[HPLC Measurement]
The HPLC measurement may be performed under any conditions as long as the peaks derived from the polymerizable liquid crystal compound (1) and the polymerizable liquid crystal compound (2) can be separated. An example of the HPLC measurement conditions is shown below.
(Measurement conditions)
Measurement device: HPLC LC-10AT (Shimadzu Corporation)
Column: L-Column ODS (inner diameter 3.0 mm, length 150 mm, particle size 3 μm)
Temperature: 40℃
Mobile phase A: 0.1% (v/v)-TFA/water Mobile phase B: 0.1% (v/v)-TFA/acetonitrile Gradient: 0 min 70%-B
30min 100%-B
60min 100%-B
60.01min 70%-B
75min 70%-B
Flow rate: 0.5mL/min
Injection volume: 5μL
Detection wavelength: 254 nm

<Preparation of polymerizable liquid crystal compound>
Synthesis Example 1: Preparation of polymerizable liquid crystal compound (2) A polymerizable liquid crystal compound represented by the following formula (2-1-1) (hereinafter referred to as "polymerizable liquid crystal compound (2-1-1)") was synthesized according to the following scheme.

A 100 mL four-neck flask equipped with a Dimroth condenser and a thermometer was filled with nitrogen, and 11.02 g of compound (E-1) synthesized with reference to patent document (JP 2010-31223), 4.22 g of compound (D-2) synthesized with reference to patent document (JP 2011-207765), 0.02 g of DMAP (Wako Pure Chemical Industries, Ltd.), 0.20 g of BHT (Wako Pure Chemical Industries, Ltd.), and 58 g of chloroform (Kanto Chemical Co., Ltd.) were added and mixed, and then 4.05 g of IPC (Wako Pure Chemical Industries, Ltd.) was further added using a dropping funnel, and these were reacted at 0 ° C. overnight. After the reaction was completed, insoluble components were removed by filtration. The obtained chloroform solution was dropped into acetonitrile (Wako Pure Chemical Industries, Ltd.) of 3 times the mass of chloroform contained in the solution to precipitate a solid. The precipitated solid was then filtered off, washed three times with 20 g of acetonitrile, and dried under reduced pressure at 30°C to obtain 11.75 g of polymerizable liquid crystal compound (2-1-1). The yield of polymerizable liquid crystal compound (2-1-1) was 81% based on compound (D-2).

Synthesis Example 2: Preparation of a mixture of polymerizable liquid crystal compound (1) and polymerizable liquid crystal compound (2)

A 100 mL four-neck flask equipped with a Dimroth condenser and a thermometer was filled with nitrogen, and 10.91 g of compound (E-1), 4.22 g of compound (D-2), 0.06 g of compound (F-3) (manufactured by Wako Pure Chemical Industries, Ltd.), 0.02 g of DMAP (manufactured by Wako Pure Chemical Industries, Ltd.), 0.20 g of BHT (manufactured by Wako Pure Chemical Industries, Ltd.), and 58 g of chloroform (manufactured by Kanto Chemical Co., Ltd.) were added and mixed, and then 4.05 g of IPC (manufactured by Wako Pure Chemical Industries, Ltd.) was further added using a dropping funnel and reacted at 0 ° C overnight. After the reaction was completed, insoluble components were removed by filtration. The obtained chloroform solution was dropped into acetonitrile (manufactured by Wako Pure Chemical Industries, Ltd.) in an amount three times the mass of chloroform contained in the solution, and a solid was precipitated. The precipitated solid was then filtered off, washed three times with 20 g of acetonitrile, and dried under reduced pressure at 30°C to obtain 12.34 g of a mixture of polymerizable liquid crystal compound (2-1-1) and polymerizable liquid crystal compound (1-1-1). The mixture thus obtained contained 5.0% of polymerizable liquid crystal compound (1-1-1) based on the total mass of the mixture. The yield of the mixture was 85.0% based on compound (D-2). Note that n in the above formula (1-1-1) is 2.

Synthesis Examples 3 to 13
Liquid crystal mixtures (1) to (12) containing the polymerizable liquid crystal compound (2-1-1) and any one of the polymerizable liquid crystal compounds (1-1-2) to (1-1-10) were prepared in the same manner as in Synthesis Example 2, except that compound (F-3) was replaced with compound (F-4) to (F-10), (F-1) or (F-2) shown in Table 1. The polymerizable liquid crystal compounds (1-1-2) to (1-1-10) each have a structure in which the propylene group in the structure represented by -O-CO-(C ₃ H ₆ )-CO-O- in the above formula (1-1-1) is replaced with an aliphatic hydrocarbon group or alicyclic group derived from compound (F-4) to (F-10), (F-1) or (F-2), respectively.

<Solubility Evaluation>
At 25°C, 1.00 g of N-methylpyrrolidone (NMP) and a stirrer were placed in a vial, and while stirring with a magnetic stirrer (HS-30DN, AS ONE), the above synthetic compounds were added until residual dissolution was visually confirmed. When residual dissolution was confirmed, the solubility of each liquid crystal mixture and polymerizable liquid crystal compound in NMP was calculated as a weight percent concentration from (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 3.

<Preparation of Polymerizable Liquid Crystal Composition>
Example 1
The liquid crystal mixture (1) of the polymerizable liquid crystal compound (1-1-1) and the polymerizable liquid crystal compound (2-1-1) obtained in Synthesis Example 2 was placed in a vial, and a polymerization initiator, a leveling agent, a polymerization inhibitor, and a solvent were added according to the composition shown in Table 2, and the mixture was stirred at 80° C. for 30 minutes using a carousel, thereby obtaining a polymerizable liquid crystal composition (1).
The amounts of the polymerization initiator, the leveling agent, and the polymerization inhibitor shown in Table 2 are amounts charged relative to 100 parts by mass of the liquid crystal mixture (1). The blending amount of the solvent was set so that the mass % of the solid content was 13% with respect to the total amount of the polymerizable liquid crystal composition.

Polymerization initiator: 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butan-1-one (Irgacure 369; manufactured by BASF Japan)
Leveling agent: polyacrylate compound (BYK-361N; manufactured by BYK Japan)
Polymerization inhibitor: BHT (Wako Pure Chemical Industries, Ltd.)
Solvent: N-methylpyrrolidone (NMP; manufactured by Kanto Chemical Co., Ltd.)

Example 2
A polymerizable liquid crystal composition (2) was obtained in the same manner as in Example 1, except that 510 mg of the liquid crystal mixture (2) of the polymerizable liquid crystal compound (1-1-2) and the polymerizable liquid crystal compound (2-1-1) obtained in Synthesis Example 3 and 490 mg of the compound (2-1-1) obtained in Synthesis Example 1 were mixed and used as the polymerizable liquid crystal compound. Using the obtained polymerizable liquid crystal composition (2), HPLC analysis was performed under the above-mentioned measurement conditions, and the area percentage value of the polymerizable liquid crystal compound (1-1-2) based on the total amount of the polymerizable liquid crystal compound (2-1-1) and the polymerizable liquid crystal compound (1-1-2) was calculated.

Examples 3 to 8 and 10 to 12
Polymerizable liquid crystal compositions (3) to (8) and (10) to (12) were obtained in the same manner as in Example 1, except that the liquid crystal mixture (1) was replaced with the liquid crystal mixtures (2) to (10), respectively.

Example 9
A polymerizable liquid crystal composition (9) was obtained in the same manner as in Example 1, except that a mixture of 500 mg of the liquid crystal mixture (8) of the polymerizable liquid crystal compound (1-1-6) and the polymerizable liquid crystal compound (2-1-1) obtained in Synthesis Example 9 and 500 mg of the compound (2-1-1) obtained in Synthesis Example 1 was used as the polymerizable liquid crystal compound. HPLC analysis was performed under the above-mentioned measurement conditions using the obtained polymerizable liquid crystal composition (9), and the area percentage value of the polymerizable liquid crystal compound (1-1-6) based on the total amount of the polymerizable liquid crystal compound (2-1-1) and the polymerizable liquid crystal compound (1-1-6) was measured.

Comparative Example 1
A polymerizable liquid crystal composition (13) was obtained in the same manner as in Example 1, except that the polymerizable liquid crystal compound (2-1-1) obtained in Synthesis Example 1 was used instead of the liquid crystal mixture (1).

Comparative Examples 2 and 3
Polymerizable liquid crystal compositions (14) and (15) were obtained in the same manner as in Example 1, except that the liquid crystal mixture (1) was replaced with the liquid crystal mixture (11) or (12) obtained in Synthesis Example 12 or 13 according to Table 3, respectively.

<Measurement of phase transition temperature>
1000 mg of the liquid crystal mixture used in the polymerizable liquid crystal compositions (1) to (15) was weighed out in a vial, and 2 g of chloroform was added to dissolve the mixture. The obtained solution was applied to a glass substrate with a PVA alignment film that had been rubbed, and then dried. The substrate was placed on a cooling and heating device (Japan High Tech Corporation's "LNP94-2") and heated from room temperature to 180°C, and then cooled to room temperature. The state of the substrate during the temperature change was observed with a polarizing microscope (LEXT, Olympus Corporation), and the temperature at which the substrate became nematic was measured and defined as the nematic phase transition temperature. The results are shown in Table 3.

<Measurement of optical properties (α value)>
For the polymerizable liquid crystal compositions (1), (3), (4), (6), (8), (10) to (12), and (15) in which M in formula (1) is an aliphatic hydrocarbon group, optical films (retardation films) were prepared and the optical properties were evaluated. The results are shown in Table 4.
[Preparation of composition for forming photoalignment film]
The following components were mixed, and the resulting mixture was stirred at 80° C. for 1 hour to obtain a composition for forming a photoalignment film.
A photoalignment material (5 parts) having the formula:
(Number average molecular weight: approx. 28,000)
Solvent (95 parts): Cyclopentanone

[Production of Optical Film (Retardation Film)]
An optical film was produced as follows. A cycloolefin polymer film (COP) (ZF-14, Zeon Corporation) was treated once using a corona treatment device (AGF-B10, Kasuga Electric Co., Ltd.) under the conditions of an output of 0.3 kW and a treatment speed of 3 m/min. The photoalignment film-forming composition was applied to the corona-treated surface using a bar coater, dried at 80°C for 1 minute, and exposed to polarized UV light at an integrated light amount of 100 mJ/ ^cm2 using a polarized UV irradiation device (SPOT CURE SP-7; Ushio Inc.). The thickness of the resulting alignment film was measured using a laser microscope (LEXT, Olympus Corporation) to find it to be 100 nm.

Each of the polymerizable liquid crystal compositions (1), (3), (4), (6), (8), (10) to (12), and (15) was applied onto an alignment film using a bar coater, and dried at 120°C for 1 minute. Then, the film was irradiated with ultraviolet light (under a nitrogen atmosphere, wavelength: 365 nm, accumulated light amount at a wavelength of 365 nm: 1000 mJ/ ^cm2 ) using a high-pressure mercury lamp (Uniqure VB-15201BY-A, manufactured by Ushio Inc.) to prepare an optical film.

The optical film prepared above was used as a measurement sample, and a measuring device (Oji Scientific Instruments' "KOBRA-WR") was used to measure the front retardation value for light with wavelengths of 450 nm and 550 nm, and the α value = Re(450)/Re(550) was calculated.

Claims (8)

A polymerizable liquid crystal compound represented by formula (1):

[In formula (1),
k11, k12 and l each independently represent an integer of 1 or more;
B ¹¹ and B ¹² each independently represent -CR ¹ R ² -, -CH ₂ -CH ₂ -, -O-, -S-, -CO-O-, -O-CO-, -O-CO-O-, -C(=S)-O-, -O-C(=S)-, -O-C(=S)-O-, -CO-NR ¹ -, -NR ² -CO-, -O-CH ₂ -, -CH ₂ -O-, -S-CH ₂ -, -CH ₂ -S- or a single bond, and R ¹ and R ² each independently represent a hydrogen atom, a fluorine atom or an alkyl group having 1 to 4 carbon atoms;
E ¹¹ and E ¹² each independently represent -CR ¹ R ² -, -CH ₂ -CH ₂ -, -O-, -S-, -CO-O-, -O-CO-, -O-CO-O-, -C(=S)-O-, -O-C(=S)-, -O-C(=S)-O-, -CO-NR ¹ -, -NR ² -CO-, -O-CH 2 -, -CH ₂ -O-, -S-CH _{2 -} , -CH ₂ -S- or a single bond;
G ¹¹ and G ¹² each independently represent a divalent alicyclic hydrocarbon group having 3 to 16 carbon atoms, a hydrogen atom contained in the alicyclic hydrocarbon group may be substituted with a halogen atom, -R ³ , -OR ³ , a cyano group or a nitro group, -CH ₂ - contained in the alicyclic hydrocarbon group may be substituted with -O-, -S- or -NH-, R ³ represents an alkyl group having 1 to 4 carbon atoms, and a hydrogen atom contained in the alkyl group may be substituted with a fluorine atom;
A ¹¹ and A ¹² each independently represent a divalent alicyclic hydrocarbon group having 3 to 16 carbon atoms, or a divalent aromatic hydrocarbon group having 6 to 20 carbon atoms, and a hydrogen atom contained in the alicyclic hydrocarbon group or the aromatic hydrocarbon group may be substituted with a halogen atom, -R ³ , -OR ³ , a cyano group, or a nitro group;
F ¹¹ and F ¹² each independently represent an alkanediyl group having 1 to 12 carbon atoms, a hydrogen atom contained in the alkanediyl group may be substituted with -OR ³ or a halogen atom, and -CH ₂ - contained in the alkanediyl group may be substituted with -O- or -CO-;
P ¹¹ and P ¹² each independently represent a hydrogen atom or a polymerizable group (provided that at least one of P ¹¹ and P ¹² is a polymerizable group);
Each M independently represents a divalent aliphatic hydrocarbon group having 2n carbon atoms (n is an integer of 2 to 4) which may have a substituent;
Ar ¹¹ and Ar ¹² each independently represent the following formula (Ar-1):

[In formula (Ar-1),
* represents a bond;
Q1 represents -S- ^;
Y ¹ represents an alkyl group having 1 to 6 carbon atoms, an aromatic hydrocarbon group which may have a substituent, or an aromatic heterocyclic group which may have a substituent;
Z ¹ and Z ² each independently represent a hydrogen atom, 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, -NR ¹¹ R ¹² , or -SR ¹¹ ; Z ¹ and Z ² may be bonded to each other to form an aromatic ring or an aromatic heterocycle; and R ¹¹ and R ¹² each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.
It represents a group represented by the following formula: A polymerizable liquid crystal composition comprising the polymerizable liquid crystal compound according to claim 1 and a polymerizable liquid crystal compound represented by formula (2).

[In formula (2),
k21 and k22 each independently represent an integer of 1 or more;
B ²¹ and B ²² each independently represent -CR ¹ R ² -, -CH ₂ -CH ₂ -, -O-, -S-, -CO-O-, -O-CO-, -O-CO-O-, -C(═S)-O-, -O-C(═S)-, -O-C(═S)-O-, -CO-NR ¹ -, -NR ² -CO-, -O-CH ₂ -, -CH ₂ -O-, -S-CH ₂ -, -CH ₂ -S- or a single bond; R ¹ and R ² each independently represent a hydrogen atom, a fluorine atom or an alkyl group having 1 to 4 carbon atoms.
E ²¹ and E ²² each independently represent -CR ¹ R ² -, -CH ₂ -CH ₂ -, -O-, -S-, -CO-O-, -O-CO-, -O-CO-O-, -C(=S)-O-, -O-C(=S)-, -O-C(=S)-O-, -CO-NR ¹ -, -NR ² -CO-, -O-CH 2 -, -CH ₂ -O-, -S-CH _{2 -} , -CH ₂ -S- or a single bond;
G ²¹ and G ²² each independently represent a divalent alicyclic hydrocarbon group having 3 to 16 carbon atoms, a hydrogen atom contained in the alicyclic hydrocarbon group may be substituted with a halogen atom, -R ³ , -OR ³ , a cyano group or a nitro group, -CH ₂ - contained in the alicyclic hydrocarbon group may be substituted with -O-, -S- or -NH-, R ³ represents an alkyl group having 1 to 4 carbon atoms, a hydrogen atom contained in the alkyl group may be substituted with a fluorine atom;
A ²¹ and A ²² each independently represent a divalent alicyclic hydrocarbon group having 3 to 16 carbon atoms, or a divalent aromatic hydrocarbon group having 6 to 20 carbon atoms, and a hydrogen atom contained in the alicyclic hydrocarbon group or the aromatic hydrocarbon group may be substituted with a halogen atom, -R ³ , -OR ³ , a cyano group, or a nitro group;
F ²¹ and F ²² each independently represent an alkanediyl group having 1 to 12 carbon atoms, a hydrogen atom contained in the alkanediyl group may be substituted with -OR ³ or a halogen atom, and -CH ₂ - contained in the alkanediyl group may be substituted with -O- or -CO-;
P ²¹ and P ²² each independently represent a hydrogen atom or a polymerizable group (provided that at least one of P ²¹ and P ²² is a polymerizable group);
Ar ²¹ is represented by the following formula (Ar-1):

[In formula (Ar-1),
* represents a bond;
Q1 represents -S- ^;
Y ¹ represents an alkyl group having 1 to 6 carbon atoms, an aromatic hydrocarbon group which may have a substituent, or an aromatic heterocyclic group which may have a substituent;
Z ¹ and Z ² each independently represent a hydrogen atom, 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, -NR ¹¹ R ¹² , or -SR ¹¹ ; Z ¹ and Z ² may be bonded to each other to form an aromatic ring or an aromatic heterocycle; and R ¹¹ and R ¹² each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.
It represents a group represented by the following formula: 3. The polymerizable liquid crystal composition according to claim 2, wherein a ratio of a peak area of the polymerizable liquid crystal compound (1) to a total peak area of the polymerizable liquid crystal compound (1) and the polymerizable liquid crystal compound ( 2 ), as measured by liquid chromatography, is 0.1% or more and 50% or less. The polymerizable liquid crystal composition according to claim 2 or 3, wherein the groups represented by A ¹¹ , A ¹² , ^{B 11} , B ¹² , E ¹¹ , E ¹² , F ¹¹ , F ¹² , G ^{11, G 12} , P ¹¹ and P ¹² in formula (1) are the same as the groups represented ^by A ²¹ , A ²² , B ²¹ , B ²² , E ²¹ , E ²² , F ²¹ , F ²² , G ²¹ , G ²² , P 21 and P ²² in formula (2), and the groups represented by Ar ¹¹ and Ar ¹² in formula (1) are the same as the group represented by Ar ²¹ in formula ( 2 ) . The polymerizable liquid crystal composition according to claim 2 , further comprising a photopolymerization initiator and an organic solvent. A retardation film formed from the polymerizable liquid crystal composition according to any one of claims 2 to 5 . A polarizing plate comprising the retardation film according to claim 6 . An optical display comprising the polarizer of claim 7 .