JP7559860B1 - Polymerizable cholesteric liquid crystal composition, optically anisotropic film, and electromagnetic wave reflective film - Google Patents

Abstract

The present invention provides a polymerizable cholesteric liquid crystal composition capable of forming an optically anisotropic film having excellent heat resistance, and an optically anisotropic film, such as an electromagnetic wave reflecting film, using the polymerizable cholesteric liquid crystal composition.
[Solution] A polymerizable cholesteric liquid crystal composition containing an achiral polymerizable liquid crystal compound having a solid-liquid crystal phase transition temperature of 50°C to 120°C, a chiral polymerizable compound having a phase transition temperature of 60°C to 90°C, and a photopolymerization initiator, and not containing a polymerizable liquid crystal compound having a fluorene skeleton.
[Selection diagram] None

Description

This disclosure relates to a polymerizable cholesteric liquid crystal composition, and an optically anisotropic film and an electromagnetic wave reflective film using the liquid crystal composition.

In recent years, polymerizable liquid crystal compounds have been used in optically anisotropic films such as polarizing plates, polarizing reflectors, and retardation plates. This is because polymerizable liquid crystal compounds exhibit optical anisotropy in the liquid crystal state, and this anisotropy is fixed by polymerization. Since the optical properties required for optically anisotropic films differ depending on the purpose, various compounds are sometimes combined and used as polymerizable liquid crystal compositions to obtain properties suited to the purpose.

Patent Documents 1 and 2 disclose polymerizable liquid crystal compositions containing a polymerizable liquid crystal compound having a fluorene skeleton and an optically active compound. The polymerizable liquid crystal compositions containing these optically active compounds can be used in a variety of applications by controlling the type and amount of the optically active compound to change the helical pitch of the optically anisotropic film having a twisted alignment. The optically anisotropic film having a twisted alignment reflects light that matches the length of the helical pitch and the direction of rotation of the helix. When the helical pitch is in the range of 380 nm to 780 nm, it reflects visible light. When the helical pitch is longer than 780 nm, it reflects near-infrared and infrared light, and when the helical pitch is shorter than 380 nm, it reflects ultraviolet light.

Other known uses of optically anisotropic films include brightness-enhancing films for displays (e.g., Patent Document 3), near-infrared reflective layers (e.g., Patent Document 4), and electromagnetic wave reflective films (e.g., Patent Document 5).

JP 2005-113131 A JP 2015-110728 A JP 2017-194709 A JP 2009-522399 A International Publication No. 2012/014552

However, the optically anisotropic film, which is a cured film of the polymerizable cholesteric liquid crystal composition specifically described in Patent Documents 1 and 2, still has insufficient heat resistance, and has a problem in that the helical pitch is easily changed by heat.
In view of the above-mentioned circumstances, an embodiment of the present disclosure aims to provide a polymerizable cholesteric liquid crystal composition capable of forming an optically anisotropic film having excellent heat resistance, and an optically anisotropic film, such as an electromagnetic wave reflective film, using the polymerizable cholesteric liquid crystal composition.

Means for Solving the Problems The present inventors have conducted intensive research to achieve the above object, and have found that heat resistance can be improved by forming a polymerizable cholesteric liquid crystal composition containing a chiral polymerizable compound having a specific phase transition temperature, an achiral polymerizable liquid crystal compound having a specific solid-liquid crystal phase transition temperature, and a photopolymerization initiator, but not containing a polymerizable liquid crystal compound having a fluorene skeleton, and have thus completed the present invention.
That is, the present disclosure includes the following aspects.

[1] A polymerizable cholesteric liquid crystal composition comprising an achiral polymerizable liquid crystal compound having a solid-liquid crystal phase transition temperature of 50°C to 120°C, a chiral polymerizable compound having a phase transition temperature of 60°C to 90°C, and a photopolymerization initiator, and not comprising a polymerizable liquid crystal compound having a fluorene skeleton.
[2] The polymerizable cholesteric liquid crystal composition according to the above [1], further comprising a non-fluorinated leveling agent.
[3] Further containing a solvent,
The polymerizable cholesteric liquid crystal composition according to the above [1] or [2], wherein the solvent contains 30 mass% or more of a solvent having a boiling point within a range of ±20° C. of the phase transition temperature of the chiral polymerizable compound in the total solvent.
[4] The polymerizable cholesteric liquid crystal composition according to any one of [1] to [3] above, wherein the achiral polymerizable liquid crystal compound is at least one selected from the group consisting of compounds represented by the following general formula (1):

（一般式（１）において、Ａｒは、１，４－フェニレン基、又はナフタレン－２，６－ジイル基を表し、
Ｌ^１及びＬ^２はそれぞれ独立して、－Ｏ－、－Ｓ－、－ＣＯＯ－、－ＯＣＯ－、－ＣＨ_２－ＣＨ_２－ＯＣＯ－、－ＯＣＯ－ＣＨ_２－ＣＨ_２－、－ＣＨ_２－ＯＣＯ－、－ＯＣＯ－ＣＨ_２－、又は、単結合を表し、
Ａ^１及びＡ^２はそれぞれ独立して、１，４－フェニレン基、１，４－シクロへキシレン基、又はナフタレン－２，６－ジイル基を表し、
前記Ａｒ、Ａ^１及びＡ^２はそれぞれ、１つ以上の置換基Ｅ^１によって置換されていても良く、当該置換基Ｅ^１は、ハロゲン、ニトロ基、シアノ基、テトラゾール基、炭素数１～７のアルキル基又は炭素数１～７のアルコキシ基であり、
Ｒ^１及びＲ^２はそれぞれ独立して、下記一般式（Ｒ－１）から選ばれる基を表し、
一般式（Ｒ－１）： －Ｌ^ｒ１－Ｒ^ｓｐ１－Ｚ^１
一般式（Ｒ－１）中、Ｌ^ｒ１は、－Ｏ－、－Ｓ－、－ＣＯＯ－、－ＯＣＯ－、－ＯＣＯＯ－、又は、単結合を表し、Ｒ^ｓｐ１は、１個の－ＣＨ_２－又は隣接していない２個以上の－ＣＨ_２－が各々独立して－Ｏ－、－ＣＯＯ－、又は－ＯＣＯ－に置き換えられても良い炭素原子数１～２０のアルキレン基又は単結合を表し、Ｚ^１は重合性官能基を表す。
ｎ１及びｎ２はそれぞれ独立して、０～２の整数を表すが、ｎ１＋ｎ２は１以上であり、
Ｌ^１、Ｌ^２、Ａ^１、及びＡ^２がそれぞれ複数存在する場合は、各々同一であっても異なっていても良い。）
［５］ 前記キラルな重合性化合物が、下記一般式（２）で表される化合物からなる群から選択される少なくとも１つである、前記［１］～［４］のいずれかに記載の重合性コレステリック液晶組成物。

In the general formula (1), Ar represents a 1,4-phenylene group or a naphthalene-2,6-diyl group.
L ¹ and L ² each independently represent -O-, -S-, -COO-, -OCO-, -CH ₂ -CH ₂ -OCO-, -OCO-CH ₂ -CH ₂ -, -CH ₂ -OCO-, -OCO-CH ₂ -, or a single bond;
A ¹ and A ² each independently represent a 1,4-phenylene group, a 1,4-cyclohexylene group, or a naphthalene-2,6-diyl group;
Each of Ar, ^A1 , and ^A2 may be substituted with one or more substituents ^E1 , and the substituents ^E1 are halogen, a nitro group, a cyano group, a tetrazole group, an alkyl group having 1 to 7 carbon atoms, or an alkoxy group having 1 to 7 carbon atoms;
R ¹ and R ² each independently represent a group selected from the following general formula (R-1):
General formula (R-1): -L ^r1 -R ^sp1 -Z ¹
In general formula (R-1), L ^r1 represents -O-, -S-, -COO-, -OCO-, -OCOO-, or a single bond, R ^sp1 represents an alkylene group having 1 to 20 carbon atoms in which one -CH ₂ - or two or more non-adjacent -CH ₂ - groups may each be independently replaced by -O-, -COO-, or -OCO-, or a single bond, and Z ¹ represents a polymerizable functional group.
n1 and n2 each independently represent an integer of 0 to 2, provided that n1+n2 is 1 or more;
When there are a plurality of L ¹ , L ² , A ¹ , and A ² , they may be the same or different.
[5] The polymerizable cholesteric liquid crystal composition according to any one of [1] to [4] above, wherein the chiral polymerizable compound is at least one selected from the group consisting of compounds represented by the following general formula (2):

（一般式（２）において、
Ｌ^３及びＬ^４はそれぞれ独立して、－Ｏ－、－Ｓ－、－ＣＯＯ－、－ＯＣＯ－、又は、単結合を表し、
Ａ^３及びＡ^４はそれぞれ独立して、１，４－フェニレン基、１，４－シクロへキシレン基、又はナフタレン－２，６－ジイル基を表し、
Ｒ^３及びＲ^４はそれぞれ独立して、下記一般式（Ｒ－２）から選ばれる基を表し、
一般式（Ｒ－２）： －Ｌ^ｒ２－Ｒ^ｓｐ２－Ｚ^２
一般式（Ｒ－２）中、Ｌ^ｒ２は、－Ｏ－、－Ｓ－、－ＣＯＯ－、－ＯＣＯ－、－ＯＣＯＯ－、又は、単結合を表し、Ｒ^ｓｐ２は、１個の－ＣＨ_２－又は隣接していない２個以上の－ＣＨ_２－が各々独立して－Ｏ－、－ＣＯＯ－、又は－ＯＣＯ－に置き換えられても良い炭素原子数１～２０のアルキレン基又は単結合を表し、Ｚ^２は重合性官能基を表す。
置換基Ｅ^２及びＥ^３はそれぞれ独立して、炭素数１～３のアルキル基、又はハロゲンであり、
ｎ３及びｎ４はそれぞれ独立して、１～３を表し、ｍ１及びｍ２はそれぞれ独立して、０～２を表し、
Ｌ^３、Ｌ^４、Ａ^３、及びＡ^４がそれぞれ複数存在する場合は、各々同一であっても異なっていても良い。）

(In the general formula (2),
^L3 and ^L4 each independently represent -O-, -S-, -COO-, -OCO-, or a single bond;
^A3 and ^A4 each independently represent a 1,4-phenylene group, a 1,4-cyclohexylene group, or a naphthalene-2,6-diyl group;
R ³ and R ⁴ each independently represent a group selected from the following general formula (R-2):
General formula (R-2): -L ^r2 -R ^sp2 -Z ²
In general formula (R-2), L ^r2 represents -O-, -S-, -COO-, -OCO-, -OCOO-, or a single bond, R ^sp2 represents an alkylene group having 1 to 20 carbon atoms in which one -CH ₂ - or two or more non-adjacent -CH ₂ - groups may each be independently replaced by -O-, -COO-, or -OCO-, or a single bond, and Z ² represents a polymerizable functional group.
Substituents ^E2 and ^E3 each independently represent an alkyl group having 1 to 3 carbon atoms or a halogen atom;
n3 and n4 each independently represent 1 to 3, m1 and m2 each independently represent 0 to 2,
When a plurality of L ³ , L ⁴ , A ³ , and A ⁴ are present, they may be the same or different.

[6] An optically anisotropic film which is a cured film of the polymerizable cholesteric liquid crystal composition according to any one of [1] to [5] above.
[7] An electromagnetic wave reflective film which is a cured film of a polymerizable cholesteric liquid crystal composition,
After heating the electromagnetic wave reflective film at 90° C. for 72 hours,
The electromagnetic wave reflective film, wherein the helical pitch of the cholesteric liquid crystal in the cured film of the polymerizable cholesteric liquid crystal composition satisfies the following formulae (A-1), (A-2), and (A-3):
P ₁ - _{P 1} ×0.05≦P ₂ ≦P ₁ +P ₁ ×0.05 (A-1)
P ₁ - _{P 1} ×0.05≦P ₃ ≦P ₁ +P ₁ ×0.05 (A-2)
P ₂ −P ₂ ×0.05≦P ₁ ≦P ₂ +P ₂ ×0.05 (A-3)
(Here, _P1 represents the length of the helical pitch including the position of the first surface of the cured film, _P2 represents the length of the helical pitch including the position of the second surface of the cured film opposite to the first surface, and _P3 represents the length of the helical pitch including the position of the center part of the cured film in the layer thickness direction.)
[8] The electromagnetic wave reflective film according to [7] above, wherein the polymerizable cholesteric liquid crystal composition is the polymerizable cholesteric liquid crystal composition according to any one of [1] to [5] above.

According to an embodiment of the present disclosure, it is possible to provide a polymerizable cholesteric liquid crystal composition capable of forming an optically anisotropic film having excellent heat resistance, and an optically anisotropic film, such as an electromagnetic wave reflective film, using the polymerizable cholesteric liquid crystal composition.

FIG. 1 is a schematic cross-sectional view showing one embodiment of an electromagnetic wave reflecting film according to the present disclosure. FIG. 2 is a schematic cross-sectional view showing one embodiment of a laminate including an electromagnetic wave reflecting film of the present disclosure. FIG. 3 is a schematic cross-sectional view showing one embodiment of a laminate including an electromagnetic wave reflecting film of the present disclosure.

Hereinafter, the embodiments and examples of the present disclosure will be described with reference to the drawings. However, the present disclosure can be implemented in many different forms, and is not to be interpreted as being limited to the description of the embodiments and examples exemplified below. In addition, the drawings may be schematic in terms of the width, thickness, shape, etc. of each part compared to the actual form in order to make the explanation clearer, but they are merely examples and do not limit the interpretation of the present disclosure. In addition, in this specification and each figure, elements similar to those described above with respect to the previous figures may be given the same reference numerals, and detailed explanations may be omitted as appropriate. In addition, for convenience of explanation, the terms "upper" and "lower" may be used in the explanation, but the up-down direction may be reversed.
"In this specification, when a certain component, region, or other structure is described as being "on (or under)" another component, region, or other structure, unless otherwise specified, this includes not only the case where the component is directly on (or directly under) the other structure, but also the case where the component is above (or below) the other structure, i.e., the case where another component is included between the component and the component, above (or below) the other structure.

In the present disclosure, the alignment regulation force refers to the action of aligning liquid crystal compounds in a specific direction.
In the present disclosure, (meth)acrylic refers to either acrylic or methacrylic, and (meth)acrylate refers to either acrylate or methacrylate.
In addition, in this specification, the terms "plate,""sheet," and "film" are not distinguished from one another solely based on the difference in name, and a "film surface (plate surface, sheet surface)" refers to a surface that coincides with the planar direction of the target film-like (plate-like, sheet-like) member when viewed overall and globally.
In addition, in the present disclosure, the use of "to" indicating a numerical range means that the numerical values before and after it are included as the lower limit and upper limit.

A. Polymerizable Cholesteric Liquid Crystal Composition The polymerizable cholesteric liquid crystal composition of the present disclosure is a polymerizable cholesteric liquid crystal composition that contains an achiral polymerizable liquid crystal compound having a solid-liquid crystal phase transition temperature of 50° C. to 120° C., a chiral polymerizable compound having a phase transition temperature of 60° C. to 90° C., and a photopolymerization initiator, and does not contain a polymerizable liquid crystal compound having a fluorene skeleton.

The polymerizable cholesteric liquid crystal composition of the present disclosure contains an achiral polymerizable liquid crystal compound having a solid-liquid crystal phase transition temperature of 50° C. to 120° C. in combination with a chiral polymerizable compound having a phase transition temperature of 60° C. to 90° C., and does not contain a polymerizable liquid crystal compound having a fluorene skeleton, so that it can be a polymerizable cholesteric liquid crystal composition with improved heat resistance and can suppress fluctuations in helical pitch before and after a heat resistance test. The mechanism by which heat resistance is improved is still unknown, but is presumed to be as follows.
The solid-liquid crystal phase transition temperature of most achiral polymerizable liquid crystal compounds is generally 50°C to 180°C, but when the compound is dissolved in a solution and a coating film is formed to obtain a liquid crystal phase, the phase transition tends to occur at a temperature lower than the solid-liquid crystal phase transition temperature. On the other hand, resin substrates such as polyethylene terephthalate (PET) substrates and triacetyl cellulose (TAC) substrates are often used as substrates for forming a cured film of the polymerizable liquid crystal composition, but such resin substrates are prone to heat wrinkles when heated at high temperatures. Therefore, the polymerizable liquid crystal composition is applied onto a substrate and heated at a temperature of usually 60°C to 120°C, preferably 110°C or less or 100°C or less, to dry the solvent and align the liquid crystal, thereby forming a coating film of the polymerizable liquid crystal composition.
The polymerizable cholesteric liquid crystal composition of the present disclosure contains a combination of an achiral polymerizable liquid crystal compound having a solid-liquid crystal phase transition temperature of 50° C. to 120° C. and a chiral polymerizable compound having a phase transition temperature of 60° C. to 90° C., and therefore when a coating film of the polymerizable cholesteric liquid crystal composition is formed and then heated at a normal preferred temperature, the chiral polymerizable compound having a phase transition temperature of 60° C. to 90° C. undergoes phase transition first, or the chiral polymerizable compound and the achiral polymerizable liquid crystal compound undergo phase transition simultaneously. In such a case, the molecular motion of the chiral polymerizable compound becomes active, and a good mixed state of the chiral polymerizable compound and the polymerizable liquid crystal compound is obtained, and a coating film having a uniform concentration of the chiral polymerizable compound and the polymerizable liquid crystal compound in the film thickness direction is obtained. In such a well-mixed coating film, the polymerizable liquid crystal compound is oriented, and then polymerization between the chiral polymerizable compound and the polymerizable liquid crystal compound proceeds, thereby improving the polymerization rate between the chiral polymerizable compound and the polymerizable liquid crystal compound. As a result, a cured film of the liquid crystal composition can be obtained which has high uniformity of the helical pitch in the film thickness direction and high heat resistance, and which has a high uniformity of the helical pitch in the film thickness direction even after a heat resistance test.
In addition, since the phase transition temperature of the chiral polymerizable compound is set to 60° C. or higher, the purity of the chiral polymerizable compound can be easily improved, bleeding in the coating film is less likely, and heat resistance can be ensured.

On the other hand, if the phase transition temperature of the chiral polymerizable compound is higher than 90°C, it becomes difficult to obtain a good mixed state between the chiral polymerizable compound and the polymerizable liquid crystal compound, and the polymerization rate between the chiral polymerizable compound and the polymerizable liquid crystal compound also becomes low, which is considered to result in low heat resistance.
In addition, since the polymerizable liquid crystal compound having a fluorene skeleton has a rigid structure and therefore has low solubility in a solvent and low compatibility with a chiral polymerizable compound, it is considered that the polymerization rate between the chiral polymerizable compound and the polymerizable liquid crystal compound is insufficient, resulting in low heat resistance (Comparative Example described later). Therefore, it is considered that the polymerizable cholesteric liquid crystal composition of the present disclosure has improved heat resistance by not containing a polymerizable liquid crystal compound having a fluorene skeleton.

The polymerizable cholesteric liquid crystal composition of the present disclosure contains at least an achiral polymerizable liquid crystal compound having a solid-liquid crystal phase transition temperature of 50°C to 120°C, a chiral polymerizable compound having a phase transition temperature of 60°C to 90°C, and a photopolymerization initiator, and does not contain a polymerizable liquid crystal compound having a fluorene skeleton, but preferably further contains a solvent. It may also further contain a leveling agent. Furthermore, it may further contain other components within a range that does not impair the effect. Each component constituting the polymerizable liquid crystal composition of the present disclosure will be described in order below.

1. Achiral polymerizable liquid crystal compound having a solid-liquid crystal phase transition temperature of 50° C. to 120° C. The achiral polymerizable liquid crystal compound having a solid-liquid crystal phase transition temperature of 50° C. to 120° C. can be appropriately selected from conventionally known polymerizable liquid crystal compounds having no asymmetric carbon atom.
In the present disclosure, the solid-liquid crystal phase transition temperature means the temperature at which a liquid crystal compound changes from a solid to a liquid crystal. In the present disclosure, the solid-liquid crystal phase transition temperature of a liquid crystal compound is measured using a differential scanning calorimeter (DSC). The measurement method using a differential scanning calorimeter (DSC) can be used to measure even when two or more liquid crystal compounds are mixed or when a chiral polymerizable compound described below is mixed.
In the present disclosure, the solid-liquid crystal phase transition temperature of a liquid crystal compound is specifically measured by the following method. The measurement is performed in accordance with JIS K7121-1987, 8. The phase transition temperature is the extrapolated melting initiation temperature (Tim) in accordance with JIS K7121-1987, 9.1(2). However, the method of preparing a sample by distilling off the solvent and the heating and cooling program (heating rate, cooling rate, heating start temperature, end temperature) are as follows.
First, a solvent is removed from the liquid crystal composition using a rotary evaporator to obtain a measurement sample. 5 mg of the measurement sample is sealed in an aluminum sample pan, and then set in a DSC. Under a nitrogen atmosphere, the sample is cooled from 25°C to -10°C at a rate of -25°C/min, and maintained at -10°C for 15 minutes. Thereafter, as a first heating step, the sample is heated from -10°C to 150°C at a rate of 10°C/min, and maintained at 150°C for 1 minute. As a first cooling step, the sample is cooled from 150°C to -10°C at a rate of -10°C/min, and maintained at -10°C for 10 minutes. Thereafter, as a second heating step, the sample is heated from -10°C to 150°C at a rate of 10°C/min, and maintained at 150°C for 1 minute. As a second cooling step, the sample is cooled from 150°C to 25°C at a rate of -10°C/min. The endothermic onset temperature detected in the second heating step, i.e., the extrapolated melting onset temperature (Tim), which is the temperature at the intersection of a straight line extending the low-temperature baseline to the high-temperature side and a tangent line drawn at the point where the slope of the curve on the low-temperature side of the melting peak is maximum, is taken as the phase transition temperature.

In addition, the DSC measurements in the present examples and comparative examples were both performed with the upper limit temperature set to 150° C. However, in the case of a compound that initiates polymerization by 150° C., the upper limit temperature of the DSC measurement is changed to be lower than the polymerization initiation temperature of the compound.
In this case, whether or not the compound is polymerized is observed according to the following procedures i) to iii) to determine the upper limit temperature for DSC measurement.
i) The temperature reached in the first heating step is set to 150°C, and if no peak is detected in the second heating step or the peak area becomes significantly smaller, a new DSC measurement is performed under conditions in which the temperature reached in the first heating step is 5°C lower.
ii) If no peak is detected in the second heating even when the temperature reached in the first heating is lowered by 5°C, or the peak area becomes significantly smaller, perform DSC measurement again under conditions in which the temperature reached in the first heating is further lowered by 5°C.
iii) Repeat ii) above until a peak is detected in the second heating. The temperature at which a peak can be detected in the second heating is set as the upper limit temperature for DSC measurement (upper limit of heating temperature).

In the present disclosure, the achiral polymerizable liquid crystal compound may be a polymerizable liquid crystal compound having a polymerizable functional group at at least one end of a mesogenic group, but from the viewpoint of improving heat resistance, it is more preferable that the compound is a polymerizable liquid crystal compound having polymerizable functional groups at both ends of a mesogenic group. A polymerizable liquid crystal compound having two or more polymerizable functional groups in one molecule can improve the hardness and durability of a coating film.
Examples of polymerizable liquid crystal compounds having two or more polymerizable functional groups in one molecule include nematic monoacrylate 2 described in Nature vol 378, page 467-469 (1995); (17) to (28) described in paragraph 0013 of JP-A-2002-145830, (a-1) to (a-35) described in paragraph 0018, (a-36) to (a-63) described in paragraph 0022; WO 2022/215751, paragraph 0336 described in chemical 74 and paragraph 0337 described in chemical 75; DIC Technical Review 2001 P38 described in M5, M6, M7, and the like compounds described in the above can be appropriately selected and used.
Examples of the achiral polymerizable liquid crystal compound used in the present disclosure include polymerizable liquid crystal compounds selected from the group consisting of compounds represented by the following general formula (1).

（一般式（１）において、Ａｒは、１，４－フェニレン基、又はナフタレン－２，６－ジイル基を表し、
Ｌ^１及びＬ^２はそれぞれ独立して、－Ｏ－、－Ｓ－、－ＣＯＯ－、－ＯＣＯ－、－ＣＨ_２－ＣＨ_２－ＯＣＯ－、－ＯＣＯ－ＣＨ_２－ＣＨ_２－、－ＣＨ_２－ＯＣＯ－、－ＯＣＯ－ＣＨ_２－、又は、単結合を表し、
Ａ^１及びＡ^２はそれぞれ独立して、１，４－フェニレン基、１，４－シクロへキシレン基、又はナフタレン－２，６－ジイル基を表し、
前記Ａｒ、Ａ^１及びＡ^２はそれぞれ、１つ以上の置換基Ｅ^１によって置換されていても良く、当該置換基Ｅ^１は、ハロゲン、ニトロ基、シアノ基、テトラゾール基、炭素数１～７のアルキル基又は炭素数１～７のアルコキシ基であり、
Ｒ^１及びＲ^２はそれぞれ独立して、下記一般式（Ｒ－１）から選ばれる基を表し、
一般式（Ｒ－１）： －Ｌ^ｒ１－Ｒ^ｓｐ１－Ｚ^１
一般式（Ｒ－１）中、Ｌ^ｒ１は、－Ｏ－、－Ｓ－、－ＣＯＯ－、－ＯＣＯ－、－ＯＣＯＯ－、又は、単結合を表し、Ｒ^ｓｐ１は、１個の－ＣＨ_２－又は隣接していない２個以上の－ＣＨ_２－が各々独立して－Ｏ－、－ＣＯＯ－、又は－ＯＣＯ－に置き換えられても良い炭素原子数１～２０のアルキレン基又は単結合を表し、Ｚ^１は重合性官能基を表す。
ｎ１及びｎ２はそれぞれ独立して、０～２の整数を表すが、ｎ１＋ｎ２は１以上であり、
Ｌ^１、Ｌ^２、Ａ^１、及びＡ^２がそれぞれ複数存在する場合は、各々同一であっても異なっていても良い。）

In the general formula (1), Ar represents a 1,4-phenylene group or a naphthalene-2,6-diyl group.
L ¹ and L ² each independently represent -O-, -S-, -COO-, -OCO-, -CH ₂ -CH ₂ -OCO-, -OCO-CH ₂ -CH ₂ -, -CH ₂ -OCO-, -OCO-CH ₂ -, or a single bond;
A ¹ and A ² each independently represent a 1,4-phenylene group, a 1,4-cyclohexylene group, or a naphthalene-2,6-diyl group;
Each of Ar, ^A1 , and ^A2 may be substituted with one or more substituents ^E1 , and the substituents ^E1 are halogen, a nitro group, a cyano group, a tetrazole group, an alkyl group having 1 to 7 carbon atoms, or an alkoxy group having 1 to 7 carbon atoms;
R ¹ and R ² each independently represent a group selected from the following general formula (R-1):
General formula (R-1): -L ^r1 -R ^sp1 -Z ¹
In general formula (R-1), L ^r1 represents -O-, -S-, -COO-, -OCO-, -OCOO-, or a single bond, R ^sp1 represents an alkylene group having 1 to 20 carbon atoms in which one -CH ₂ - or two or more non-adjacent -CH ₂ - groups may each be independently replaced by -O-, -COO-, or -OCO-, or a single bond, and Z ¹ represents a polymerizable functional group.
n1 and n2 each independently represent an integer of 0 to 2, provided that n1+n2 is 1 or more;
When there are a plurality of L ¹ , L ² , A ¹ , and A ² , they may be the same or different.

L ¹ and L ² each independently represent -O-, -S-, -COO-, -OCO-, -CH ₂ -CH ₂ -OCO-, -OCO-CH 2 -CH ₂ -, -CH ₂ -OCO-, -OCO-CH ₂ -, or a single bond. From the viewpoint of availability of raw materials and ease of synthesis, it is preferable that L 1 and L 2 each independently represent -O-, -COO-, -OCO-, or a single bond, and when a plurality of L 1 and L ₂ are present, they may be the same or different.

1,4-cyclohexylene in ^A1 and ^A2 may exist as cis- or trans-stereoisomers based on the difference in the configuration of the carbon atom bonding to ^L1 , ^L2 , or ^Lr1 . 1,4-cyclohexylene may be either cis- or trans-isomer, or may be a mixture of cis- and trans-isomers, but is preferably either trans- or cis-isomer, and more preferably trans-isomer, because it has good orientation.

n1 and n2 each independently represent an integer from 0 to 2, and n1+n2 is 1 or more, but may be 2 or more and 3 or less.

Specifically, in terms of availability of raw materials and ease of synthesis, R ^sp1 in general formula (R-1) preferably each independently represents an alkylene group having 1 to 12 carbon atoms which may be replaced by one -CH ₂ - or two or more non-adjacent -CH ₂ - groups each independently represents an alkylene group having 1 to 12 carbon atoms or a single bond, more preferably each independently represents an alkylene group having 1 to 12 carbon atoms or a single bond, even more preferably each independently represents an alkylene group having 2 to 10 carbon atoms, and particularly preferably each independently represents an alkylene group having 2 to 6 carbon atoms, and when there are a plurality of R sp1, they may be the same or different.

In general formula (R-1), L ^r1 represents -O-, -S-, -COO-, -OCO-, -OCOO-, or a single bond. From the viewpoint of availability of raw materials and ease of synthesis, it is preferable that each L r1 independently represents -O-, -COO-, -OCO-, -OCOO-, or a single bond, and when a plurality of L r1 are present, they may be the same or different.

In the general formula (R-1), Z ¹ represents a polymerizable functional group. The polymerizable functional group used in the present disclosure may be any group used in a conventional polymerizable liquid crystal compound without any restrictions. Examples of the polymerizable functional group include cyclic ether-containing groups such as an oxirane ring and an oxetane ring, and ethylenic double bond-containing groups. Among these, ethylenic double bond-containing groups are preferred because they exhibit photocurability and are easy to handle.
The polymerizable functional groups in ^Z1 each preferably independently represent a group selected from the following formulae (Z-1) to (Z-7), in which * (asterisk) indicates the bonding position with ^Rsp1 .

（式（Ｚ－１）～（Ｚ－７）中、Ｒ^ｚはそれぞれ独立して、水素原子、フッ素原子、塩素原子、臭素原子、ヨウ素原子、メチル基、エチル基、又はトリフルオロメチル基である。）

(In formulas (Z-1) to (Z-7), R ^z is each independently a hydrogen atom, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a methyl group, an ethyl group, or a trifluoromethyl group.)

In the case where ultraviolet polymerization is performed as the polymerization method, Z ¹ is preferably formula (Z-1), formula (Z-2), formula (Z-3), formula (Z-5), or formula (Z-7), more preferably formula (Z-1), formula (Z-3), or formula (Z-7), still more preferably formula (Z-1), and further preferably the case where in formula (Z-1), R ^z is a hydrogen atom, a methyl group, or a trifluoromethyl group.

The substituent E ¹ which may be substituted on Ar, A ¹ and A ² includes a halogen, a nitro group, a cyano group, a tetrazole group, an alkyl group having 1 to 7 carbon atoms and an alkoxy group having 1 to 7 carbon atoms.
The halogen may be fluorine, chlorine, bromine or iodine, preferably fluorine, chlorine or bromine.
The alkyl group having 1 to 7 carbon atoms may be either linear or branched, and examples thereof include linear alkyl groups such as a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an n-pentyl group, an n-hexyl group, and an n-heptyl group, and branched alkyl groups such as an i-propyl group, an i-butyl group, a t-butyl group, and a 2-methylbutyl group. The alkyl group may have 1 to 5 carbon atoms, or may have 1 to 3 carbon atoms.
The alkoxy group having 1 to 7 carbon atoms is represented by -OR ^a (wherein R ^a is an alkyl group having 1 to 7 carbon atoms). Examples of R ^a in -OR ^a include the same as the alkyl group having 1 to 7 carbon atoms, and may be an alkoxy group having 1 to 5 carbon atoms or an alkoxy group having 1 to 3 carbon atoms.
The number of the substituents ^E1 may be 0 to 3, 0 to 2, or 0 or 1 in each of Ar, ^A1 , and ^A2 .

As the mesogen group contained in the polymerizable liquid crystal compound and -(A ¹ -L ¹ ) _n1 -Ar-(L ² -A ² ) _n2 -, partial structures represented by the following chemical formulae (m-1) to (m-11) are preferably used, and among them, from the viewpoint of solvent solubility, partial structures represented by at least one selected from the group consisting of the following chemical formulae (m-2), (m-3), (m-5), (m-7), (m-8) and (m-10) are preferably used. The hydrogen atom in the phenylene group or naphthylene group in the partial structures represented by the following chemical formulae (m-1) to (m-11) may be substituted with the substituent E ¹ .

The achiral polymerizable liquid crystal compound used in the present disclosure may be a polymerizable liquid crystal compound having a structure shown in Lc-1 to Lc-120 in the following table as specific examples of R ¹ -(A ¹ -L ¹ ) _n1 -Ar-(L ² -A ² ) _n2 -R ² in general formula (1) and having a solid-liquid crystal phase transition temperature of 50° C. to 120° C., but is not limited thereto.

In the structures represented by Lc-1 to Lc-120, n in R ^sp1 represents 1 to 20. Among them, n in R ^sp1 is preferably 2 or more, more preferably 4 or more, while it is preferably 12 or less, more preferably 10 or less, and may be 6 or less.
In addition, in ^Z1 , ^Rz in formula (Z-1) is preferably each independently a hydrogen atom or a methyl group, more preferably a hydrogen atom.
In the structures represented by Lc-1 to Lc-120, R ¹ and R ² may be different, and for example, n in R ^sp1 may be different.

Furthermore, in the structures represented by Lc-1 to Lc-120, the 1,4-phenylene group or naphthalene-2,6-diyl group of Ar, and the 1,4-phenylene groups or naphthalene-2,6-diyl groups of A ¹ and A ² may each be substituted with one or more of the substituents E ^1. Specifically, the 1,4-phenylene group or naphthalene-2,6-diyl group of Ar, A ¹ and A ² may each have the following structure, for example.

The solid-liquid crystal phase transition temperature of the achiral polymerizable liquid crystal compound used in the present disclosure, which has a solid-liquid crystal phase transition temperature of 50°C to 120°C, is preferably 50°C to 100°C in terms of the load on the manufacturing equipment that aligns the liquid crystal, and may be 50°C to 90°C or 50°C to 80°C.

In addition, the achiral polymerizable liquid crystal compound having a solid-liquid crystal phase transition temperature of 50°C to 120°C used in the present disclosure is preferably soluble in at least one solvent selected from the group consisting of methyl ethyl ketone, methyl isobutyl ketone, cyclopentanone, and cyclohexanone at a concentration of 10% by mass or more, and more preferably soluble at 20% by mass or more, in terms of improving the solvent solubility of the polymerizable cholesteric liquid crystal composition. When the solvent solubility of the polymerizable liquid crystal composition is improved, a uniform coating film is easily formed when the polymerizable cholesteric liquid crystal composition is used to form a coating film, and the load on the manufacturing process and manufacturing equipment for drying the solvent is reduced, the options for usable substrates are expanded, and the process margin during alignment is expanded, resulting in more uniform and better alignment.

In addition, in order to improve heat resistance, the present disclosure does not contain a polymerizable liquid crystal compound having a fluorene skeleton. Here, a polymerizable liquid crystal compound having a fluorene skeleton refers to a compound that contains a fluorene skeleton represented by the following structure, among polymerizable liquid crystal compounds having a polymerizable functional group at at least one end of a mesogen group.

（式中、Ｗ^１１は独立して水素原子または置換基を表す。）

(In the formula, W ¹¹ independently represents a hydrogen atom or a substituent.)

The achiral polymerizable liquid crystal compound having a solid-liquid crystal phase transition temperature of 50°C to 120°C used in the present disclosure can be synthesized by a conventionally known synthesis method, and can be synthesized by appropriately referring to Makromol. Chem., 190, 3201-3215 (1989), Makromol. Chem., 190, 2255-2268 (1989), International Publication No. 97/000600, U.S. Patent No. 5,770,107, JP-A No. 2004-231638, etc. In addition, the achiral polymerizable liquid crystal compound having a solid-liquid crystal phase transition temperature of 50°C to 120°C may be appropriately selected from commercially available products.

The achiral polymerizable liquid crystal compound having a solid-liquid crystal phase transition temperature of 50° C. to 120° C. used in the present disclosure may be used alone or in combination of two or more.
The content ratio of the achiral polymerizable liquid crystal compound having a solid-liquid crystal phase transition temperature of 50° C. to 120° C. used in the present disclosure may be appropriately adjusted in order to adjust the desired optical anisotropy, etc., and is not limited thereto, and may be 75% by mass to 99% by mass, 85% by mass to 96% by mass, or 90% by mass to 96% by mass, relative to the total solid content of the polymerizable cholesteric liquid crystal composition.

In the polymerizable cholesteric liquid crystal composition of the present disclosure, a liquid crystal compound other than the achiral polymerizable liquid crystal compound having a solid-liquid crystal phase transition temperature of 50°C to 120°C may be used within a range in which the effects of the present invention are not impaired. As the liquid crystal compound other than the achiral polymerizable liquid crystal compound having a solid-liquid crystal phase transition temperature of 50°C to 120°C, a conventionally known liquid crystal compound can be used. In the polymerizable cholesteric liquid crystal composition of the present disclosure, the achiral polymerizable liquid crystal compound having a solid-liquid crystal phase transition temperature of 50°C to 120°C is preferably 50% by mass or more, may be 70% by mass or more, may be 80% by mass or more, or may be 100% by mass, based on the total amount of the achiral liquid crystal compound, in terms of improving heat resistance.

2. Chiral polymerizable compound having a phase transition temperature of 60° C. to 90° C. Chiral polymerizable compounds have the function of inducing a helical structure of a cholesteric liquid crystal phase as a chiral agent. Chiral polymerizable compounds (chiral agents) generally contain an asymmetric carbon atom, but may be axially asymmetric compounds or planarly asymmetric compounds that do not contain an asymmetric carbon atom.
The chiral polymerizable compound may or may not exhibit liquid crystallinity. When the chiral polymerizable compound exhibits liquid crystallinity, the phase transition temperature is a solid-liquid phase transition temperature, and when the chiral polymerizable compound does not exhibit liquid crystallinity, the phase transition temperature is a solid-liquid phase transition temperature.
The solid-liquid phase transition temperature of the chiral polymerizable compound is measured in the same manner as the achiral polymerizable liquid crystal compound. The solid-liquid phase transition temperature of the chiral polymerizable compound when it does not exhibit liquid crystallinity is also measured using a differential scanning calorimeter (DSC) in the same manner as the achiral polymerizable liquid crystal compound. A measurement sample is set in the DSC, and heating and cooling are repeated twice, and the endothermic onset temperature (extrapolated melting onset temperature) detected in the second heating is taken as the phase transition temperature of the chiral polymerizable compound. The upper limit of the measurement temperature is determined to be lower than the polymerization onset temperature measured by measuring the polymerization onset temperature of the compound.

In the present disclosure, since both the chiral polymerizable compound and the polymerizable liquid crystal compound have a polymerizable functional group, a polymer can be formed by a polymerization reaction between the chiral polymerizable compound and the polymerizable liquid crystal compound, and heat resistance can be improved. Therefore, it is preferable that the polymerizable functional group of the chiral polymerizable compound is the same type of group as the polymerizable functional group of the polymerizable liquid crystal compound. That is, when the polymerizable functional group of the polymerizable liquid crystal compound is a radical polymerizable group such as the unsaturated polymerizable group as in (Z-1) and (Z-2), the polymerizable functional group of the chiral polymerizable compound is also a radical polymerizable group, and when the polymerizable functional group of the polymerizable liquid crystal compound is a cationic polymerizable group as in (Z-3) to (Z-7), the polymerizable functional group of the chiral polymerizable compound may also be a cationic polymerizable group.

In the present disclosure, examples of the chiral polymerizable compound having a phase transition temperature of 60° C. to 90° C. can be appropriately selected from the compounds described in, for example, the chiral polymerizable compounds having a phase transition temperature of 60° C. to 90° C. described in paragraphs [0127] to [0139] of JP-A No. 2015-135474, the chiral polymerizable compounds having a phase transition temperature of 60° C. to 90° C. described in paragraph [0209] of JP-A No. 2015-127793, and the chiral polymerizable compounds having a phase transition temperature of 60° C. to 90° C. described in paragraph [0210] of JP-A No. 2015-110728.
Examples of the chiral polymerizable compound used in the present disclosure include polymerizable compounds selected from the group consisting of compounds represented by the following general formula (2).

（一般式（２）において、
Ｌ^３及びＬ^４はそれぞれ独立して、－Ｏ－、－Ｓ－、－ＣＯＯ－、－ＯＣＯ－、又は、単結合を表し、
Ａ^３及びＡ^４はそれぞれ独立して、１，４－フェニレン基、１，４－シクロへキシレン基、又はナフタレン－２，６－ジイル基を表し、
Ｒ^３及びＲ^４はそれぞれ独立して、下記一般式（Ｒ－２）から選ばれる基を表し、
一般式（Ｒ－２）： －Ｌ^ｒ２－Ｒ^ｓｐ２－Ｚ^２
一般式（Ｒ－２）中、Ｌ^ｒ２は、－Ｏ－、－Ｓ－、－ＣＯＯ－、－ＯＣＯ－、又は、単結合を表し、Ｒ^ｓｐ２は、１個の－ＣＨ_２－又は隣接していない２個以上の－ＣＨ_２－が各々独立して－Ｏ－、－ＣＯＯ－、又は－ＯＣＯ－に置き換えられても良い炭素原子数１～２０のアルキレン基又は単結合を表し、Ｚ^２は重合性官能基を表す。
置換基Ｅ^２及びＥ^３はそれぞれ独立して、炭素数１～３のアルキル基、又はハロゲンであり、
ｎ３及びｎ４はそれぞれ独立して、１～３を表し、ｍ１及びｍ２はそれぞれ独立して、０～２を表し、
Ｌ^３、Ｌ^４、Ａ^３、及びＡ^４がそれぞれ複数存在する場合は、各々同一であっても異なっていても良い。）

(In the general formula (2),
^L3 and ^L4 each independently represent -O-, -S-, -COO-, -OCO-, or a single bond;
^A3 and ^A4 each independently represent a 1,4-phenylene group, a 1,4-cyclohexylene group, or a naphthalene-2,6-diyl group;
R ³ and R ⁴ each independently represent a group selected from the following general formula (R-2):
General formula (R-2): -L ^r2 -R ^sp2 -Z ²
In general formula (R-2), L ^r2 represents -O-, -S-, -COO-, -OCO-, or a single bond, R ^sp2 represents an alkylene group having 1 to 20 carbon atoms in which one -CH ₂ - or two or more non-adjacent -CH ₂ - groups may each be independently replaced by -O-, -COO-, or -OCO-, or a single bond, and Z ² represents a polymerizable functional group.
Substituents ^E2 and ^E3 each independently represent an alkyl group having 1 to 3 carbon atoms or a halogen atom;
n3 and n4 each independently represent 1 to 3, m1 and m2 each independently represent 0 to 2,
When a plurality of L ³ , L ⁴ , A ³ , and A ⁴ are present, they may be the same or different.

^L3 and ^L4 each independently represent -O-, -S-, -COO-, -OCO-, or a single bond. From the viewpoint of availability of raw materials and ease of synthesis, it is preferable that L3 and L4 each independently represent -O-, -COO-, -OCO-, or a single bond, and when a plurality of L3 and L4 are present, they may be the same or different.

The 1,4-cyclohexylene in ^A3 and ^A4 may be the same as the 1,4-cyclohexylene in ^A1 and ^A2 .
In addition, L ^r2 , R ^sp2 and Z ² in the general formula (R-2) may be the same as L ^r1 , R ^sp1 and Z ¹ in the general formula (R-1) of the general formula (1), respectively.

n3 and n4 each independently represent 1 to 3, but may be appropriately selected depending on the phase transition temperature.

Examples of the alkyl group having 1 to 3 carbon atoms or the halogen atom in the substituents ^E2 and ^E3 include the same as those exemplified for the substituent ^E1 .
m1 and m2 each independently represent an integer of 0 to 2, and may be 0 or 1.

As the chiral polymerizable compound used in the present disclosure, specific examples of -(L ³ -A ³ ) _n3 -R ³ and -(L ⁴ -A ⁴ ) _n4 -R ⁴ in general formula (2) include polymerizable compounds having structures shown in Ch-1 to Ch-60 in the following table and having a phase transition temperature of 60° C. to 90° C., but are not limited thereto.
In the table, L ³ /L ⁴ where n3 and n4=1 is the side bonded to the binaphthalene moiety, and for example, Ch-13 has n3 and n4=2, and A ³ /A ⁴ where n3 and n4=2 is bonded to R ³ /R ⁴ .

In the structures represented by Ch-1 to Ch-60, n in R ^sp2 represents 1 to 20. Among them, n in R ^sp2 is preferably 2 or more, more preferably 4 or more, while it is preferably 12 or less, more preferably 10 or less, and may be 6 or less.
In addition, in ^Z2 , ^Rz in formula (Z-1) is preferably each independently a hydrogen atom or a methyl group, more preferably a hydrogen atom.
In the structures represented by Ch-1 to Ch-60, R ³ and R ⁴ may be different, and for example, n in R ^sp2 may be different.

In the compound represented by the general formula (2), each binaphthalene may be substituted with one or more of the substituents ^E1 , and specifically, for example, may have the following structure:

In addition, examples of chiral polymerizable compounds having a phase transition temperature of 60°C to 90°C that can be used in the present invention are not limited to the polymerizable compounds represented by the general formula (2) above, and include, for example, the following polymerizable compounds.

The phase transition temperature of the chiral polymerizable liquid crystal compound used in the present disclosure, which has a phase transition temperature of 60°C to 90°C, may be 60°C to 80°C in view of the load on the manufacturing equipment that causes the phase transition of the liquid crystal mixture by heating.

In addition, the chiral polymerizable liquid crystal compound having a phase transition temperature of 60°C to 90°C used in the present disclosure is preferably soluble in at least one solvent selected from the group consisting of methyl ethyl ketone, methyl isobutyl ketone, cyclopentanone, and cyclohexanone at a concentration of 10% by mass or more, and more preferably soluble at 20% by mass or more, in order to improve the solvent solubility of the polymerizable cholesteric liquid crystal composition. When the solvent solubility of the polymerizable liquid crystal composition is improved, a uniform coating film is easily formed when the polymerizable cholesteric liquid crystal composition is used to form a coating film, and the load on the manufacturing process and manufacturing equipment for drying the solvent is reduced, the options for usable substrates are expanded, and the process margin during alignment is expanded, resulting in more uniform and better alignment.

The chiral polymerizable compound having a phase transition temperature of 60°C to 90°C used in the present disclosure can be synthesized by a conventionally known synthesis method, for example, by appropriately referring to JP-A-2005-263778, GB2298202, DE19843724, etc. In addition, the chiral polymerizable compound having a phase transition temperature of 60°C to 90°C may be appropriately selected from commercially available products.

The chiral polymerizable compound having a phase transition temperature of 60° C. to 90° C. used in the present disclosure may be used alone or in combination of two or more kinds.
The content ratio of the chiral polymerizable compound having a phase transition temperature of 60° C. to 90° C. used in the present disclosure may be appropriately adjusted in order to adjust the desired optical anisotropy, etc., and is not limited thereto, and may be 0.01% by mass to 15% by mass, 1% by mass to 10% by mass, or 1% by mass to 5% by mass, relative to the total solid content of the polymerizable cholesteric liquid crystal composition.

In the polymerizable cholesteric liquid crystal composition of the present disclosure, a chiral compound different from the chiral polymerizable compound having a phase transition temperature of 60°C to 90°C may be used within a range in which the effects of the present invention are not impaired. As a chiral compound different from the chiral polymerizable compound having a phase transition temperature of 60°C to 90°C, a chiral agent of a conventionally known cholesteric liquid crystal composition can be used. However, in the polymerizable cholesteric liquid crystal composition of the present disclosure, the chiral polymerizable compound having a phase transition temperature of 60°C to 90°C is preferably 90% by mass or more, and may be 100% by mass, based on the total amount of chiral compounds, in terms of improving heat resistance.

3. Photopolymerization Initiator In the present disclosure, the photopolymerization initiator can be appropriately selected from conventionally known initiators according to the polymerizable functional groups of the achiral polymerizable liquid crystal compound and the chiral polymerizable compound.
When the polymerizable functional group of the achiral polymerizable liquid crystal compound and the chiral polymerizable compound is a radical polymerizable group, a radical polymerization initiator can be used, and when the polymerizable functional group is a cationic polymerizable group, a cationic polymerization initiator can be used.

Specific examples of such photopolymerization initiators include aromatic ketones including thioxanthone, α-aminoalkylphenones, α-hydroxyketones, acylphosphine oxides, oxime esters, aromatic onium salts, organic peroxides, thio compounds, hexaarylbiimidazole compounds, ketoxime ester compounds, borate compounds, azinium compounds, metallocene compounds, active ester compounds, compounds having a carbon-halogen bond, and alkylamine compounds. Among these, at least one selected from the group consisting of acylphosphine oxide-based polymerization initiators, α-aminoalkylphenone-based polymerization initiators, α-hydroxyketone-based polymerization initiators, and oxime ester-based polymerization initiators is preferred, as it hardens to the inside of the coating film and improves durability.

Examples of acylphosphine oxide polymerization initiators include bis(2,4,6-trimethylbenzoyl)-phenyl-phosphine oxide (e.g., trade name: Irgacure 819, manufactured by BASF), bis(2,6-dimethoxybenzoyl)-2,4,4-trimethyl-pentylphenylphosphine oxide, and 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide (trade name: Lucirin TPO, manufactured by BASF, etc.).

Examples of α-aminoalkylphenone polymerization initiators include 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one (e.g., Irgacure 907, manufactured by BASF), 2-benzyl-2-(dimethylamino)-1-(4-morpholinophenyl)-1-butanone (e.g., Irgacure 369, manufactured by BASF), and 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-morpholinyl)phenyl]-1-butanone (Irgacure 379EG, manufactured by BASF).

Examples of α-hydroxyketone polymerization initiators include 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]-phenyl}-2-methyl-propan-1-one (e.g., trade name: Irgacure 127, manufactured by BASF, etc.), 2-hydroxy-4'-hydroxyethoxy-2-methylpropiophenone (e.g., trade name: Irgacure 2959, manufactured by BASF, etc.), 1-hydroxy-cyclohexyl-phenyl-ketone (e.g., trade name: Irgacure 184, manufactured by BASF, etc.), and oligo{2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propanone} (e.g., trade name: ESACURE ONE, manufactured by Lamberti, etc.).

Examples of oxime ester polymerization initiators include 1,2-octanedione, 1-[4-(phenylthio)-, 2-(O-benzoyloxime)] (product name: Irgacure OXE-01, manufactured by BASF), ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-, 1-(o-acetyloxime) (product name: Irgacure OXE-02, manufactured by BASF), methanone, ethanone, 1-[9-ethyl-6-(1,3-dioxolane, 4-(2-methoxyphenoxy)-9H-carbazol-3-yl]-, 1-(o-acetyloxime) (product name: ADEKA OPT-N-1919, manufactured by ADEKA Corporation).

In the present disclosure, the photopolymerization initiator may be used alone or in combination of two or more kinds.
In the present disclosure, the content ratio of the photopolymerization initiator may be 0.5% by mass to 10% by mass, 0.5% by mass to 8% by mass, or 0.5% by mass to 5% by mass, relative to the total solid content of the polymerizable cholesteric liquid crystal composition, from the viewpoint of promoting curing of the polymerizable compound.

4. Leveling Agent The polymerizable cholesteric liquid crystal composition of the present disclosure may further contain a leveling agent in order to make the surface tension of the coating film uniform and improve the coatability.
From the viewpoint of making the surface tension of the coating film uniform and improving the coatability, the leveling agent may be a nonionic surfactant, and examples of the nonionic surfactant include vinyl-based, silicone-based, fluorine-based, and hydrocarbon-based surfactants.
In order to make the surface tension of the coating film uniform and improve the coating property, the leveling agent used in the polymerizable cholesteric liquid crystal composition of the present disclosure is preferably a non-fluorine-based leveling agent. Examples of the non-fluorine-based leveling agent include vinyl-based, silicone-based, and hydrocarbon-based surfactants. When a non-fluorine-based leveling agent is used, there is a tendency that the reflectance increases and the haze is reduced.

Examples of the vinyl surfactant include polyalkyl acrylate, polyalkyl methacrylate, polyalkyl vinyl ether, polybutadiene, polyolefin, and polyvinyl ether.
Examples of silicone surfactants include polydimethylsiloxane, polyphenylsiloxane, specially modified siloxane, fluorine-modified siloxane, and surface-treated siloxane.
Examples of the hydrocarbon surfactant include polyethylene, polypropylene, polyisobutylene, paraffin, liquid paraffin, chlorinated polypropylene, chlorinated paraffin, and chlorinated liquid paraffin.

The leveling agents may be used alone or in combination of two or more.
Among these, from the viewpoint of making the surface tension of the coating film uniform and improving the coatability, vinyl surfactants which are nonionic surfactants are preferred, and acrylic surfactants such as polyalkyl acrylates (acrylic polymers) or polyalkyl methacrylates are more preferred.
Examples of acrylic surfactants containing such acrylic polymers or acrylic (co)polymers as the main component include the Polyflow series (No. 7, No. 50E, No. 50EHF, No. 54N, No. 75, No. 77, No. 85, No. 85HF, No. 90, No. 90D-50, No. 95, No. 99C), the TEGO Flow series (300, 370, ZFS460), and the BYK series (350, 352, 354, 355, 356, 358N, 361N, 381, 392, 394, 3441, 3440).

In the present disclosure, the leveling agent may be used alone or in combination of two or more kinds.
In the present disclosure, when a leveling agent is contained in the polymerizable cholesteric liquid crystal composition, the content ratio thereof may be 0.0001% by mass to 0.5% by mass, 0.0002% by mass to 0.01% by mass, or 0.0003% by mass to 0.05% by mass, relative to the total solid content of the polymerizable cholesteric liquid crystal composition.

The polymerizable cholesteric liquid crystal composition of the present disclosure may further contain a solvent from the viewpoint of coatability. The solvent may be appropriately selected from conventionally known solvents capable of dissolving or dispersing each component contained in the polymerizable cholesteric liquid crystal composition.
Examples of the solvent include ester-based solvents, amide-based solvents, alcohol-based solvents, ether-based solvents, glycol monoalkyl ether-based solvents, aromatic hydrocarbon-based solvents, halogenated aliphatic hydrocarbon-based solvents, alicyclic hydrocarbon-based solvents, ketone-based solvents, and acetate-based solvents.

Preferred examples of the ester solvent include ethyl acetate, propyl acetate, isopropyl acetate, methyl propionate, and isobutyl acetate.
Preferred examples of the amide solvent include N,N-dimethylacetamide and N,N-dimethylformamide.
Preferred examples of the alcohol solvent include ethanol, 1-propanol, 2-propanol, and 1-butanol.
Preferred examples of the ether solvent include ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, diethylene glycol methyl ethyl ether, bis(2-propyl)ether, 1,3-dioxolane, 1,4-dioxane, tetrahydrofuran (THF), methyltetrahydrofuran, and 4-methyltetrahydropyran.

Preferred examples of glycol monoalkyl ether solvents include ethylene glycol monomethyl ether, ethylene glycol monobutyl ether, diethylene glycol monoethyl ether, propylene glycol monomethyl ether, propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, and the like.
Preferred examples of the aromatic hydrocarbon solvent include toluene, anisole, and xylene.
Preferred examples of the halogenated aliphatic hydrocarbon solvent include chloroform and monochlorobenzene.
Preferred examples of the alicyclic hydrocarbon solvent include cyclohexane and methylcyclohexane.

Preferred examples of the ketone solvent include acetone, methyl ethyl ketone, methyl isobutyl ketone, 2-heptanone, cyclohexanone, cyclopentanone, and methyl propyl ketone.
Preferred examples of acetate solvents include ethylene glycol monomethyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, methyl acetoacetate, and 1-methoxy-2-propyl acetate.

The solvents may be used alone or in combination of two or more.
From the viewpoint of viscosity and electrical conductivity related to the suitability for coating, the solvent may be at least one selected from the group consisting of ketone-based solvents and ester-based solvents.

In terms of improving heat resistance, the polymerizable cholesteric liquid crystal composition of the present disclosure preferably contains 30% by mass or more of a solvent having a boiling point within the range of the phase transition temperature of the chiral polymerizable compound ±20° C. in the total solvent. When the solvent having a boiling point within the range of the phase transition temperature of the chiral polymerizable compound ±20° C. is contained in 30% by mass or more in the total solvent, evaporation of the solvent and phase transition of the chiral polymerizable compound become competitive in the coating and drying process, so that the chiral polymerizable compound is uniformly distributed in the film, and heat resistance can be improved.
The solvent having a boiling point within the range of the phase transition temperature of the chiral polymerizable compound ±20° C. may be, among others, a solvent having a boiling point within the range of the phase transition temperature of the chiral polymerizable compound or higher and the phase transition temperature of the chiral polymerizable compound + 20° C. or lower.
In the present disclosure, the boiling point of a solvent refers to the boiling point at 1 atmospheric pressure.

In the polymerizable cholesteric liquid crystal composition of the present disclosure, in order to improve heat resistance and make the pitch uniform, the solvent may be a mixed solvent of at least one solvent selected from the group consisting of solvents having a boiling point within the range of the phase transition temperature of the chiral polymerizable compound ±20°C and at least one solvent selected from the group consisting of solvents having a boiling point exceeding the phase transition temperature of the chiral polymerizable compound + 20°C, and the solvent may be a mixed solvent of at least one solvent selected from the group consisting of solvents having a boiling point within the range of the phase transition temperature of the chiral polymerizable compound or higher and the phase transition temperature of the chiral polymerizable compound + 20°C or lower and at least one solvent selected from the group consisting of solvents having a boiling point exceeding the phase transition temperature of the chiral polymerizable compound + 20°C. The upper limit of the boiling point of at least one solvent selected from the group consisting of solvents having a boiling point exceeding the phase transition temperature of the chiral polymerizable compound + 20°C may be 205°C or lower.

When the polymerizable cholesteric liquid crystal composition of the present disclosure contains a solvent, the content ratio may be appropriately set in consideration of the optimal viscosity at the time of application, and is not particularly limited. The solvent may be 70% by mass to 85% by mass, or 80% by mass to 85% by mass, based on the total amount of the polymerizable cholesteric liquid crystal composition including the solvent.

6. Other Components The polymerizable liquid crystal composition of the present disclosure may further contain other components within a range that does not impair the effects. Specifically, the composition may contain other components such as an antistatic agent, a light stabilizer, an ultraviolet absorber, an antioxidant, a curing assistant, an acrylate resin, etc. These may be appropriately selected from conventionally known materials.

The polymerizable liquid crystal composition of the present disclosure can be analyzed for each component using a conventionally known analytical method.
When determining the phase transition temperatures of an achiral polymerizable liquid crystal compound and a chiral polymerizable compound from a polymerizable liquid crystal composition, the achiral polymerizable liquid crystal compound and the chiral polymerizable compound may be first isolated, and then each phase transition temperature may be determined.
Examples of the isolation method that can be used include silica gel chromatography, preparative HPLC, and reprecipitation.
From the phase transition temperature and the results of NMR measurement of the isolated compound, it can be confirmed whether it is an achiral polymerizable liquid crystal compound or a chiral polymerizable compound.
For each of the isolated compounds (achiral polymerizable liquid crystal compound, chiral polymerizable compound), a DSC measurement is performed as described in the Examples below to determine the endothermic peak (phase transition temperature) of each compound alone. By comparing the endothermic peak (phase transition temperature) of the DSC measurement of the compound alone with the detection temperature of the endothermic peak of the DSC measurement of the polymerizable liquid crystal composition (mixed state), the peaks of the achiral polymerizable liquid crystal compound and the chiral polymerizable compound in the polymerizable liquid crystal composition can be distinguished.

The polymerizable cholesteric liquid crystal composition of this embodiment has good heat resistance and is therefore suitable for use in a variety of applications. The polymerizable cholesteric liquid crystal composition of this embodiment is suitable for use in a variety of optical components, such as electromagnetic wave reflective films, brightness enhancing films for displays, and heat shielding films, as described below.

B. Optically Anisotropic Film The optically anisotropic film of the present disclosure is a cured film of the polymerizable cholesteric liquid crystal composition of the present disclosure.
The optically anisotropic film of the present disclosure is a polymer composition obtained by forming a film from the polymerizable cholesteric liquid crystal composition of the present disclosure, twisting the polymerizable liquid crystal compound in the formed film of the polymerizable cholesteric liquid crystal composition, and polymerizing the aligned polymerizable liquid crystal compound and the chiral polymerizable compound. The twisted alignment is fixed by polymerizing the aligned polymerizable liquid crystal compound and the chiral polymerizable compound.

The film formation of the polymerizable cholesteric liquid crystal composition of the present disclosure may be performed by uniformly applying the polymerizable cholesteric liquid crystal composition onto a support that has been subjected to an alignment treatment to form a coating film.
By appropriately adjusting the coating amount of the polymerizable cholesteric liquid crystal composition and the concentration of the polymerizable cholesteric liquid crystal composition, the film thickness is adjusted so as to provide the desired optical anisotropy.

Examples of the support include glass substrates and resin substrates. Examples of the resin substrate include transparent resin substrates formed using resins such as acetyl cellulose resins such as triacetyl cellulose, polyester resins such as polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, and polylactic acid, olefin resins such as polypropylene, polyethylene, and polymethylpentene, acrylic resins, polyurethane resins, polyethersulfone, polycarbonate, polysulfone, polyether, polyetherketone, acrylonitrile, methacrylonitrile, cycloolefin polymers, and cycloolefin copolymers. These supports may be subjected to a conventionally known surface treatment such as corona treatment or plasma treatment, or may be laminates.

Examples of the alignment treatment on the support include surface treatments such as conventionally known rubbing treatment and photoalignment treatment, and a conventionally known horizontal alignment film can be appropriately selected and used.
The rubbing treatment may be directly applied to the supporting substrate, or a polymer coating may be provided in advance on the supporting substrate, and the rubbing treatment may be applied to the polymer coating.

When the alignment control force is imparted by the rubbing method, a polymer that exerts an alignment control force by rubbing is used for the horizontal alignment film. Examples of the polymer include polyvinyl alcohol, polyimide, polyamide, and derivatives thereof, and among them, polyvinyl alcohol is preferable.
The method for forming the horizontal alignment film by the rubbing method may be appropriately selected from conventionally known methods. For example, a coating film containing the above polymer is formed on the support, and then the coating film is rubbed with a known rubbing roller or the like to obtain a horizontal alignment film.

When forming a horizontal alignment film by a photo-alignment method, a photo-alignment composition containing a photo-alignment material that exerts an alignment control force by irradiating polarized light is used as the alignment film composition. The photo-alignment material may be a photodimerization type material or a photoisomerization type material. Specifically, for example, cinnamate, coumarin, benzylidenephthalimidine, benzylideneacetophenone, diphenylacetylene, stilbazole, uracil, quinolinone, maleimide, or a polymer having a cinnamylidene acetic acid derivative can be mentioned, and among them, a polymer having at least one of cinnamate and coumarin, and their derivatives are preferably used. Specific examples of such photodimerization-type materials include the compounds described in JP-A-9-118717, JP-T-10-506420, JP-T-2003-505561, WO2010/150748, JP-A-2015-151548, and JP-A-2021-103225.

The method for forming a photo-alignment film by the photo-alignment method may be appropriately selected from conventionally known methods. For example, the photo-alignment composition is uniformly applied onto the support, irradiated with polarized light, and then the entire surface of the coating film is irradiated with light to obtain a photo-alignment film.

The coating method may be selected as appropriate as long as it can form a film with the desired thickness with high accuracy. Examples include gravure coating, reverse coating, knife coating, dip coating, spray coating, air knife coating, spin coating, roll coating, printing, immersion and pulling up, curtain coating, die coating, casting, bar coating, extrusion coating, and E-type coating.

The polymerizable liquid crystal compound in the polymerizable cholesteric liquid crystal composition thus formed is twistedly aligned by adjusting and heating the composition to a temperature at which the polymerizable liquid crystal compound in the polymerizable cholesteric liquid crystal composition thus formed can be aligned.
The heating may be carried out simultaneously with drying of the solvent contained in the polymerizable cholesteric liquid crystal composition when the composition is formed into a film.
By the heat treatment, the main chain portion having an orientation property of the polymerizable liquid crystal compound can be aligned and dried, and the aligned state can be fixed.
The temperature at which alignment is possible differs depending on each substance in the polymerizable cholesteric liquid crystal composition, and therefore needs to be adjusted appropriately. The polymerizable cholesteric liquid crystal composition of the present disclosure contains an achiral polymerizable liquid crystal compound having a solid-liquid crystal phase transition temperature of 50° C. to 120° C. and a chiral polymerizable compound having a phase transition temperature of 60° C. to 90° C., and from the viewpoint of improving heat resistance, the heat treatment is preferably performed within a range of, for example, 60° C. to 120° C.
As the heating means, known heating and drying means can be appropriately selected and used.
The heating time may be appropriately selected, for example, within the range of 10 seconds to 2 hours, and preferably 20 seconds to 30 minutes.

After the orientation step, the polymerizable liquid crystal compound and the chiral polymerizable compound are polymerized. The polymerization method for forming the cured film can be appropriately selected according to the polymerizable functional group contained in the polymerizable liquid crystal compound of the present disclosure. In the orientation step, the polymerizable liquid crystal compound can be polymerized by, for example, irradiating the coating film fixed while maintaining at least the orientation state of the polymerizable liquid crystal compound, and an optically anisotropic film, which is a cured film of the polymerizable cholesteric liquid crystal composition, can be obtained.

The wavelength of light used for the light irradiation is not particularly limited, but it is preferable to match it as closely as possible to the maximum absorption wavelength of the photopolymerization initiator. Electron beams, ultraviolet rays, visible light, infrared rays (heat rays), etc. can be used. Usually, ultraviolet rays or visible light are used.
The wavelength range is 150 to 500 nm. A preferred range is 220 to 450 nm, and a more preferred range is 250 to 400 nm. Examples of the light source are low pressure mercury lamps (germicidal lamps, fluorescent chemical lamps, black lights), high pressure discharge lamps (high pressure mercury lamps, metal halide lamps), and short arc discharge lamps (ultra-high pressure mercury lamps, xenon lamps, mercury xenon lamps). Preferred examples of the light source are metal halide lamps, xenon lamps, ultra-high pressure mercury lamps, and high pressure mercury lamps. The wavelength range of the irradiation light source may be selected by placing a filter or the like between the light source and the polymerizable liquid crystal layer to pass only a specific wavelength range.
The amount of light irradiated from the light source is usually 2 to 10,000 mJ/ ^cm2 when it reaches the coating surface. The preferred range of the amount of light is 10 to 3,000 mJ/ ^cm2 , and more preferably 100 to 2,000 mJ/ ^cm2 . The polymerization environment may be any of a nitrogen atmosphere, an inert gas atmosphere, and an air atmosphere, but a nitrogen atmosphere or an inert gas atmosphere is preferred from the viewpoint of improving curability.

The support and alignment film may be peeled off and removed after the optically anisotropic film is formed.

The optically anisotropic film thus obtained is suitable for use in a variety of optical component applications, including electromagnetic wave reflective films, brightness-enhancing films for displays, and heat-shielding films, as described below.

C. Electromagnetic Wave Reflecting Film The electromagnetic wave reflecting film of the present disclosure is an electromagnetic wave reflecting film which is a cured film of a polymerizable cholesteric liquid crystal composition,
After heating the electromagnetic wave reflective film at 90° C. for 72 hours,
The helical pitch of the cholesteric liquid crystal in the cured film of the polymerizable cholesteric liquid crystal composition satisfies the following formulae (A-1), (A-2), and (A-3).
P ₁ - _{P 1} ×0.05≦P ₂ ≦P ₁ +P ₁ ×0.05 (A-1)
P ₁ - _{P 1} ×0.05≦P ₃ ≦P ₁ +P ₁ ×0.05 (A-2)
P ₂ −P ₂ ×0.05≦P ₁ ≦P ₂ +P ₂ ×0.05 (A-3)
(Here, _P1 represents the length of the helical pitch including the position of the first surface of the cured film, _P2 represents the length of the helical pitch including the position of the second surface of the cured film opposite to the first surface, and _P3 represents the length of the helical pitch including the position of the center part of the cured film in the layer thickness direction.)

The electromagnetic wave reflective film of the present disclosure is an electromagnetic wave reflective film having high heat resistance and high uniformity of the helical pitch in the film thickness direction, since the helical pitch of the cholesteric liquid crystal in the cured film of the polymerizable cholesteric liquid crystal composition satisfies the formulas (A-1), (A-2), and (A-3) after the electromagnetic wave reflective film is heated at 90°C for 72 hours.

Cholesteric liquid crystal phases are known to exhibit selective reflectivity at specific wavelengths.
In a typical cholesteric liquid crystal phase, the central wavelength of selective reflection (selective reflection central wavelength) λ depends on the helical pitch P in the cholesteric liquid crystal phase, and follows the relationship between the average refractive index n of the cholesteric liquid crystal phase and λ = n × P. Therefore, the selective reflection central wavelength can be adjusted by adjusting the helical pitch.
The longer the helical pitch, the longer the selective reflection central wavelength of the cholesteric liquid crystal phase becomes.
The helical pitch is one pitch (helical period) of the helical structure of the cholesteric liquid crystal phase, in other words, one turn of the helix, that is, the length in the helical axis direction in which the director (the long axis direction in the case of a rod-shaped liquid crystal compound) of the liquid crystal compound constituting the cholesteric liquid crystal phase rotates 360°.

The helical pitch of the cholesteric liquid crystal phase depends on the type and concentration of the chiral compound (chiral agent) used together with the achiral liquid crystal compound when forming a cured film of the polymerizable cholesteric liquid crystal composition. Therefore, by adjusting these, the desired helical pitch can be obtained.

In addition, cholesteric liquid crystal phases exhibit selective reflection for either left-handed or right-handed circularly polarized light at a specific wavelength. Whether the reflected light is right-handed or left-handed circularly polarized light depends on the helical twist direction of the cholesteric liquid crystal phase. When the helical twist direction of the cholesteric liquid crystal layer is right-handed, right-handed circularly polarized light is reflected, and when the helical twist direction is left-handed, left-handed circularly polarized light is reflected.
The direction of rotation of the cholesteric liquid crystal phase can be adjusted by the type of achiral liquid crystal compound and/or the type of chiral compound (chiral agent) that forms the cholesteric liquid crystal layer.

FIG. 1 is a schematic diagram showing an example of a striped pattern of bright areas B and dark areas D that can be seen when a cross section of an electromagnetic wave reflective film according to the present disclosure is observed using a scanning transmission electron microscope (STEM).
As shown in FIG. 1, in the cross section of the electromagnetic wave reflection film 10 of the present disclosure, which is a cured film of a polymerizable cholesteric liquid crystal composition, a layered structure in which light parts B (continuous lines formed by light parts B) and dark parts D (continuous lines formed by dark parts D) are alternately laminated is usually observed. In the STEM cross section as shown in FIG. 1, the light parts B and the dark parts D are observed due to the liquid crystal compound being helically oriented in the cured film of the polymerizable cholesteric liquid crystal composition, and the orientation of the liquid crystal compound differs depending on the position in the thickness direction (vertical direction in FIG. 1). Therefore, in the STEM cross section of the cured film of the polymerizable cholesteric liquid crystal composition, the length of one pitch of the helical structure (helical period) is the thickness of four layers, the light parts B, the dark parts D, the light parts B, and the dark parts D.

In the electromagnetic wave reflective film 10 of the present disclosure, the helical pitch of the cholesteric liquid crystal in the cured film of the polymerizable cholesteric liquid crystal composition satisfies the following formulas (A-1), (A-2), and (A-3) after the electromagnetic wave reflective film is heated at 90° C. for 72 hours. Therefore, in the electromagnetic wave reflective film 10 of the present disclosure, the helical pitch of the cholesteric liquid crystal in the cured film of the polymerizable cholesteric liquid crystal composition usually satisfies the following formulas (A-1), (A-2), and (A-3) even before the electromagnetic wave reflective film 10 is heated at 90° C. for 72 hours.
P ₁ - _{P 1} ×0.05≦P ₂ ≦P ₁ +P ₁ ×0.05 (A-1)
P ₁ - _{P 1} ×0.05≦P ₃ ≦P ₁ +P ₁ ×0.05 (A-2)
P ₂ −P ₂ ×0.05≦P ₁ ≦P ₂ +P ₂ ×0.05 (A-3)
Here, _P1 represents the length of the helical pitch including the position of a first surface S1 of the cured film, _P2 represents the length of the helical pitch including the position of a second surface S2 opposite to the first surface S1 of the cured film, and _P3 represents the length of the helical pitch including the position of a central part C in the layer thickness direction of the cured film.

The helical pitch in the electromagnetic wave reflective film of the present disclosure is determined by observing a cross section of the electromagnetic wave reflective film using a scanning transmission electron microscope (STEM).
Specifically, the center of a sample of an electromagnetic wave reflecting film (optically anisotropic film) is cut into a rectangular shape (2 mm x 5 mm), embedded in a thermosetting resin, and then cut with a microtome to produce an ultrathin section (thickness 80 nm) with a smooth cross section. The obtained ultrathin section is observed with an STEM under the following measurement conditions (detector TE, acceleration voltage 30 kV, emission current 10 μA, magnification 5000 times) to obtain a cross-sectional image of the electromagnetic wave reflecting film (optically anisotropic film). In the cross-sectional image obtained using the STEM, one pitch is dark part D-light part B-dark part D-light part B, or light part B-dark part D-light part B-dark part D, and one pitch is measured using cross-sectional image analysis software (manufactured by Hitachi High-Tech, Data Manager).
For one field of view, the locations corresponding to pitch lengths _P1 , _P2 , and _P3 are each measured three times, and the averages of the three measurements are designated as _P1 , _P2 , and _P3 . The pitch length is found by using analysis software to draw a straight line at the locations corresponding to dark area D-light area B-dark area D-light area B, or light area B-dark area D-light area B-dark area D, and then calculating the length of that line on the analysis software.

Since it is desirable for the electromagnetic wave reflective film of the present disclosure to have a wavelength reflection band that does not change due to heat, it is more preferable that the helical pitch of the cholesteric liquid crystal in the cured film of the polymerizable cholesteric liquid crystal composition before and after heating at 90° C. for 72 hours satisfy the following formulas (A'-1), (A'-2), and (A'-3), and it is even more preferable that the helical pitch of the cholesteric liquid crystal in the cured film of the polymerizable cholesteric liquid crystal composition satisfy the following formulas (A"-1), (A"-2), and (A"-3).
P ₁ - _{P 1} ×0.03≦P ₂ ≦P ₁ +P ₁ ×0.03 (A'-1)
P ₁ - _{P 1} ×0.03≦P ₃ ≦P ₁ +P ₁ ×0.03 (A'-2)
P ₂ -P ₂ ×0.03≦P ₁ ≦P ₂ +P ₂ ×0.03 (A'-3)
P ₁ - _{P 1} ×0.02≦P ₂ ≦P ₁ +P ₁ ×0.02 (A”-1)
P ₁ - _{P 1} ×0.02≦P ₃ ≦P ₁ +P ₁ ×0.02 (A”-2)
P ₂ - _{P 2} ×0.02≦P ₁ ≦P ₂ +P ₂ ×0.02 (A”-3)

Moreover, in terms of heat resistance, the electromagnetic wave reflective film of the present disclosure preferably satisfies the following formula (B).
Formula (B)
ΔPave={|(P _1b −P _1a )|/P _1b +|(P _2b −P _2a )|/P _2b +|(P _3b −P _3a )|/P _3b }/3 ≦ 0.05
(Here, P _1b represents the length of the helical pitch including the position of the first surface S1 of the cured film before heating at 90° C. for 72 hours, P _1a represents the length of the helical pitch including the position of the first surface S1 of the cured film after heating at 90° C. for 72 hours, P _2b represents the length of the helical pitch including the position of the second surface S2 opposite to the first surface S1 of the cured film before heating at 90° C. for 72 hours, P _2a represents the length of the helical pitch including the position of the second surface S2 opposite to the first surface S1 of the cured film after heating at 90° C. for 72 hours, P _3b represents the length of the helical pitch including the position of the central part C in the layer thickness direction of the cured film before heating at 90° C. for 72 hours, and P _3a represents the length of the helical pitch including the position of the central part C in the layer thickness direction of the cured film after heating at 90° C. for 72 hours.)

The ΔPave may be 0.04 or less, 0.03 or less, 0.02 or less, or 0.01 or less.

In the electromagnetic wave reflecting film 10 of FIG. 1, the striped pattern (layered structure) of the bright areas B (continuous lines formed by the bright areas B) and the dark areas D (continuous lines formed by the dark areas D) is formed so as to be parallel to the surface (formation surface) of the cured film. In this embodiment, the electromagnetic wave reflecting film 10 exhibits specular reflectivity. In other words, when light is incident from the normal direction of the electromagnetic wave reflecting film 10, the light is reflected in the normal direction.

The electromagnetic wave reflective film of the present disclosure preferably has a reflectance of 42% or more, and more preferably 45% or more, in the reflection wavelength range of 315 nm to 1000 nm.
In this disclosure, the reflected wavelength and reflectance are measured using a spectrophotometer.
More specifically, if the electromagnetic wave reflective film has a resin substrate, it is peeled off and the electromagnetic wave reflective film is transferred to adhesive glass to prepare a measurement sample. The measurement sample transferred to the glass is measured with black tape attached to the glass surface to prevent reflected light from the back side from affecting the measurement value.
The reflectance measurement is performed in accordance with JIS R3106-2019, and the reflection spectrum is measured using a spectrophotometer at wavelengths of 380 nm to 780 nm. The specular reflection of a barium sulfate white plate is used as the baseline, and the measurement position of the sample is the center position of the sample.
The obtained spectrum is analyzed using the UV-Visible spectrophotometer software, and a line graph is created with the reflection wavelength on the horizontal axis and the reflectance on the vertical axis. The reflection wavelength and reflectance at the peak top position of the created line graph are adopted as the measured values. If the peak shape is a trapezoid, the center position of the upper side of the trapezoid is regarded as the peak top.

The electromagnetic wave reflective film of the present disclosure preferably has a haze of 1.5% or less, and more preferably 1.0% or less.
In the present disclosure, the haze is measured using a haze meter in accordance with JIS K7361-1:2000. The haze value is determined by cutting an electromagnetic wave reflective film into a size of 50 mm x 50 mm, measuring each electromagnetic wave reflective film three times, and averaging the values obtained by the three measurements. "Measured three times" does not mean measuring the same place three times, but measuring three different places.

The electromagnetic wave reflective film of the present disclosure is a cured film of a polymerizable cholesteric liquid crystal composition, and may be produced by appropriately selecting a polymerizable cholesteric liquid crystal composition containing a polymerizable liquid crystal compound and a chiral agent, and the electromagnetic wave reflective film of the present disclosure may be a cured film of the polymerizable cholesteric liquid crystal composition of the present disclosure.

The thickness of the electromagnetic wave reflective film disclosed herein varies depending on the purpose, but as a guideline, it is 1 μm to 15 μm, with a preferred range of 1 μm to 10 μm and a more preferred range of 2 μm to 6 μm.

The fact that the electromagnetic wave reflective film of the present disclosure is a cured film of a polymerizable cholesteric liquid crystal composition can be confirmed by collecting and analyzing material from the electromagnetic wave reflective film. NMR, IR, GC-MS, XPS, TOF-SIMS, and combinations of these methods can be used as analytical methods.

The electromagnetic wave reflective film of the present disclosure can be manufactured using a polymerizable cholesteric liquid crystal composition in the same manner as the optically anisotropic film of the present disclosure.

The electromagnetic wave reflection film of the present disclosure may be a laminate including an electromagnetic wave reflection film. Each of Figs. 2 and 3 shows an embodiment of a laminate including an electromagnetic wave reflection film of the present disclosure. An embodiment of the laminate 100 including an electromagnetic wave reflection film shown in the example of Fig. 2 is a laminate in which an orientation film 30 and an electromagnetic wave reflection film 10 are laminated in this order on a support 20. An embodiment of the laminate 100 including an electromagnetic wave reflection film shown in the example of Fig. 3 is a laminate in which an electromagnetic wave reflection film 10 is laminated on a support 20'. The laminate 100 including an electromagnetic wave reflection film shown in the example of Fig. 3 may be subjected to an orientation treatment that exerts an orientation regulating force on the surface of the support 20' on the electromagnetic wave reflection film 10 side.
The support, alignment film, and alignment treatment in the laminate may be the same as those explained for the optically anisotropic film.
In the laminate, the electromagnetic wave reflective film may be a single layer, or may be a laminate of two or more layers.

The present invention will be specifically described below based on examples. The materials, reagents, amounts of substances and their ratios, operations, etc. shown in the following examples can be appropriately changed without departing from the spirit of the present invention. Therefore, the present invention is not limited to the following examples.
Incidentally, Example 10 below is a reference example.

<Method for measuring solid-liquid crystal phase transition temperature or solid-liquid phase transition temperature>
Measurement was performed using a differential scanning calorimeter (DSC) (Shimadzu Science, DSC-60) according to the following method. The measurement was performed in accordance with JIS K7121-1987, 8. The phase transition temperature was the extrapolated melting initiation temperature (Tim) according to JIS K7121-1987, 9.1(2). However, the method of preparing the sample by distilling off the solvent and the heating and cooling program (heating rate, cooling rate, heating start temperature, end temperature) were as follows.
First, the solvent was removed from the liquid crystal composition using a rotary evaporator to obtain a measurement sample. 5 mg of the measurement sample was sealed in an aluminum sample pan, and then set in a DSC, and cooled from 25°C to -10°C at a rate of -25°C/min under a nitrogen atmosphere, and maintained at -10°C for 15 minutes. Thereafter, as a first heating step, the temperature was raised from -10°C to 150°C at a rate of 10°C/min, and maintained at 150°C for 1 minute. As a first cooling step, the temperature was lowered from 150°C to -10°C at a rate of -10°C/min, and maintained at -10°C for 10 minutes. Thereafter, as a second heating step, the temperature was raised from -10°C to 150°C at a rate of 10°C/min, and maintained at 150°C for 1 minute. As a second cooling step, the temperature was lowered from 150°C to 25°C at a rate of -10°C/min. The endothermic onset temperature detected in the second heating, i.e., the extrapolated melting onset temperature (Tim), which is the temperature at the intersection of a straight line extending the low-temperature baseline to the high-temperature side and a tangent line drawn at the point where the slope of the curve on the low-temperature side of the melting peak is maximum, was determined as the phase transition temperature.

The compounds used in the examples and comparative examples are shown below.
(1-A); Solid-liquid crystal phase transition temperature: 80° C.
(1-B); Solid-liquid crystal phase transition temperature: 54° C.
(1-C); Solid-liquid crystal phase transition temperature: 120° C.
(C1-a): Polymerizable liquid crystal compound having a fluorene skeleton, solid-liquid crystal phase transition temperature: 84° C.
(2-A); Phase transition temperature: 76° C.
(2-B); Phase transition temperature: 60° C.
(2-C); Phase transition temperature: 76° C. (optical isomer of 2-A above)
(2-D); Phase transition temperature: 88° C.
(C2-a); Phase transition temperature: 110° C.
(C2-b); Phase transition temperature: 138° C.

The compound (1-A) used was a reagent commercially available from Tokyo Chemical Industry Co., Ltd.
The compound (1-B) used was Paliocolor LC242, available from BASF.
The compound (1-C) was synthesized by the following method. Compound 1 (5.0 g), triethylamine hydrochloride (TEA.HCl) (7.7 g), and sodium azide (2.0 g) were added to 20 mL of toluene and stirred at 110 ° C. for 5 hours. The reaction solution was cooled to 60 ° C., and then 30 mL of water was added. After stirring for 15 minutes, the mixture was left to stand, and the aqueous layer was recovered by liquid separation. 35% hydrochloric acid was added to the recovered aqueous layer until the pH reached 4, and the resulting solid was recovered by filtration. The recovered solid was dried under reduced pressure at 40 ° C. to obtain compound 2 (6.2 g). Compound 1 (1.5 g) and compound 3 (7.7 g) synthesized with reference to Japanese Patent Application No. 2019-116420 were added to 15 mL of chloroform, and then dimethylaminopyridine (0.01 g) and N,N'-diisopropylcarbodiimide (3.0 g) were added at 15 ° C., and the mixture was stirred for 4 hours. Next, 500 mL of methanol was added, and the precipitated solid was collected by filtration. The collected solid was dried under reduced pressure at 40° C. to obtain compound (1-C).

The compound (C1-a) was synthesized according to the method described in JP 2003-238491 A.

The compounds (2-A), (2-B) and (2-C) were synthesized by combining the methods described in JP 2005-263778 A, U.S. Pat. No. 5,886,242 and GB Patent Application Publication No. 2,298,202. In the compounds (2-A) and (2-B), the R-configuration was used for the binaphthalene moiety. In the compound (2-C), the S-configuration was used for the binaphthalene moiety.

The compound (2-D) was synthesized by the following method.
Compound 4 (1.1 g) and 4-hydroxybenzoic acid (1.0 g) were added to 10 mL of methylene chloride, and then dimethylaminopyridine (0.01 g) and N,N'-diisopropylcarbodiimide (1.4 g) were added at 15°C and stirred for 1 hour. The solvent was removed from the reaction solution, and the mixture was purified by silica gel column chromatography to obtain the following compound 5 (2.6 g). Next, compound 5 (2.6 g) and compound 6 (4.8 g) obtained from Merck (Sigma-Aldrich) were added to 20 mL of methylene chloride, and then dimethylaminopyridine (0.01 g) and N,N'-diisopropylcarbodiimide (1.3 g) were added at 15°C and stirred for 4 hours. Next, 200 mL of methanol was added, and the precipitated solid was collected by filtration. The collected solid was purified by silica gel column chromatography to obtain compound (2-D) (5.6 g).

The compound (C2-a) used was Paliocolor LC756, available from BASF.

The compound (C2-b) was synthesized by the following method.
Compound 7 (10.0 g) and compound 8 (15.0 g) were added to 100 mL of methylene chloride, and then dimethylaminopyridine (0.1 g) and N,N'-diisopropylcarbodiimide (8.0 g) were added at 15°C, and the mixture was stirred for 17 hours. Next, 500 mL of methanol was added, and the precipitated solid was collected by filtration. The collected solid was purified by silica gel column chromatography to obtain compound 9 (0.5 g). Compound 3 (0.5 g) and compound 4 (0.1 g) were added to 10 mL of methylene chloride, and then dimethylaminopyridine (0.01 g) and N,N'-diisopropylcarbodiimide (0.1 g) were added at 15°C, and the mixture was stirred for 5 hours. The reaction mixture was concentrated under reduced pressure, and the concentrated residue was purified by silica gel column chromatography to obtain compound (C2-b) (0.1 g).

[Example 1]
(1) Production of Polymerizable Cholesteric Liquid Crystal Composition 24.5 parts by mass of an achiral polymerizable liquid crystal compound (compound (1-A)), 0.5 parts by mass of a chiral polymerizable compound (compound (2-A)), 1 part by mass of a photopolymerization initiator (Omnirad 907, manufactured by Tokyo Chemical Industry Co., Ltd.), and 0.01 part by mass of a leveling agent (acrylic surfactant, Polyflow No. 75, manufactured by Kyoeisha Chemical Co., Ltd.) were dissolved in 24 parts by mass of methyl ethyl ketone (MEK) and 50 parts by mass of methyl isobutyl ketone (MIBK) to produce polymerizable cholesteric liquid crystal composition 1.

(2) Production of electromagnetic wave reflective film (optically anisotropic film) (2-1) Formation of photo-alignment film A composition for photo-alignment film was prepared in the same manner as in the photo-alignment film material of Example 1 of JP-A No. 2021-103225.
The composition for photoalignment film was applied by spin coating onto one side of a PET substrate (Toyobo Co., Ltd., E5100, thickness 38 μm) so that the film thickness after curing would be 0.2 μm, and then dried and thermally cured by heating in an oven at 90° C. for 2 minutes to form a cured coating film. Thereafter, the surface of this cured coating film was irradiated with polarized ultraviolet light containing an emission line of 313 nm using a Hg-Xe lamp and a Glan-Taylor prism in a direction perpendicular to the substrate normal at an exposure dose of 100 mJ/ ^cm2 to form an alignment film.

(2-2) Preparation of electromagnetic wave reflection film (optically anisotropic film) The polymerizable cholesteric liquid crystal composition 1 was applied onto the formed alignment film so that the film thickness after curing would be about 4 μm, forming a film of the polymerizable liquid crystal composition. After that, the film was dried in an oven at 90° C. for 2 minutes, and then irradiated with ultraviolet light (UV) at an irradiation dose of 400 mJ/cm ² using an H bulb manufactured by Fusion Co., Ltd. under a nitrogen atmosphere to form an electromagnetic wave reflection film (optically anisotropic film).

[Examples 2 to 15, Comparative Examples 1 to 3]
(1) Preparation of polymerizable cholesteric liquid crystal compositions Polymerizable cholesteric liquid crystal compositions 2 to 15 and comparative polymerizable cholesteric liquid crystal compositions 1 to 3 were obtained in the same manner as in Example 1, except that the type and/or amount of at least one of the achiral polymerizable liquid crystal compound, the chiral polymerizable compound, the solvent, and the leveling agent in Example 1 was changed according to Table 5 below.
(2) Production of electromagnetic wave reflective films (optically anisotropic films) In Example 1, except that polymerizable cholesteric liquid crystal compositions 2 to 15 and comparative polymerizable cholesteric liquid crystal compositions 1 to 3 were used instead of the polymerizable cholesteric liquid crystal composition 1, and the drying temperature was set to the temperature shown in Table 5, electromagnetic wave reflective films (optically anisotropic films) 2 to 15 and comparative electromagnetic wave reflective films (optically anisotropic films) 1 to 3 were obtained in the same manner as in Example 1.

[evaluation]
<Sample Creation>
The PET substrate of the electromagnetic wave reflection film (optically anisotropic film) obtained in each Example and Comparative Example was peeled off, and the electromagnetic wave reflection film (optically anisotropic film) and the alignment film were transferred to adhesive glass (Corning EagleXG glass (50 mm x 50 mm) bonded with Lintec adhesive CLEAR-PET50-06-50) to obtain a sample, and the reflectance and haze were measured. The electromagnetic wave reflection film of the sample transferred to the glass was also cut to a size of 50 mm x 50 mm.

<Measurement of reflection wavelength and reflectance>
For the electromagnetic wave reflective film (optically anisotropic film) obtained in each of the Examples and Comparative Examples, the reflection wavelength and reflectance were measured using a spectrophotometer (UV2700, manufactured by Shimadzu Corporation).
For the samples to be measured, black tape (vinyl tape No. 200-50-21 manufactured by Yamato) was attached to the entire glass side of the samples transferred onto the glass to prevent reflected light from the back side from affecting the measured values.
The reflectance measurement was performed according to JIS R3106-2019, and the reflection spectrum was measured from a measurement wavelength of 380 nm to 780 nm. The specular reflection light of the barium sulfate white plate was used as the baseline, and the measurement position of the sample was the center position of the sample. The measurement was performed once.
The obtained spectrum was analyzed by UVProbe (Shimadzu Corporation, UV-Visible Spectrophotometer software) and a line graph was created with the reflection wavelength on the horizontal axis and the reflectance on the vertical axis. The reflection wavelength and reflectance at the peak top position of the created line graph were adopted as the measured values. When the peak shape was a trapezoid, the center position of the upper side of the trapezoid was taken as the peak top.
If the reflectance is 5% or more, it is determined that a cholesteric liquid crystal phase is formed.

<Measurement of helical pitch>
Ultrathin sections were prepared using a microtome for the cross sections of the electromagnetic wave reflective films (optically anisotropic films) obtained in each Example and Comparative Example, and observed under a scanning transmission electron microscope (STEM, Hitachi High-Technologies Corporation, S-4800) to measure the length of the helical pitch.
Specifically, the center of a film sample of an electromagnetic wave reflection film (optically anisotropic film) was cut into a rectangular shape (2 mm x 5 mm), and then embedded in a thermosetting resin (Liquid A (62 mL of Lubeac 812 manufactured by Nacalai Tesque and 100 mL of dodecenyl succinic anhydride (DDSA) manufactured by Fuji Film Wako) and Liquid B (a mixture of methyl nadic anhydride (MNA) manufactured by Merck and DMP30 (trade name, obtained from Nissin EM) in a ratio of Liquid A:Liquid B of 7:3 (volume ratio)) prepared according to the Luft method at 80°C for 6 hours by hardening, and then cut with a microtome to prepare an ultrathin section (thickness 80 nm) by cutting out a smooth cross section. The obtained ultrathin cross section was measured by STEM under the following measurement conditions (detector The cross-sectional image of the electromagnetic wave reflective film (optically anisotropic film) was obtained by observation under STEM (TE, accelerating voltage 30 kV, emission current 10 μA, magnification 5000 times). In the cross-sectional image obtained using STEM, one pitch is dark area D-light area B-dark area D-light area B, or light area B-dark area D-light area B-dark area D, and the length of one pitch was measured using cross-sectional image analysis software (Hitachi High-Tech, Data Manager).
For one visual field, measurements were made at locations corresponding to pitch lengths _P1 , _P2 , and _P3 (n=3 each), and the average values were designated as _P1 , _P2 , and _P3 . The pitch length was determined by drawing a straight line using analysis software at the locations corresponding to dark area D-light area B-dark area D-light area B, or light area B-dark area D-light area B-dark area D, and then calculating the length of the line on the analysis software.

<Heat resistance test>
The electromagnetic wave reflective film (optically anisotropic film) thus obtained was heated in an oven at 90° C. for 72 hours.
After heating at 90° C. for 72 hours, the electromagnetic wave reflective film (optically anisotropic film) was subjected to measurement of the helical pitch as described above.
(Evaluation Criteria for Helical Pitch Variation)
A: Satisfies the following formulas (A''-1), (A''-2), and (A''-3).
P ₁ - _{P 1} ×0.02≦P ₂ ≦P ₁ +P ₁ ×0.02 (A”-1)
P ₁ - _{P 1} ×0.02≦P ₃ ≦P ₁ +P ₁ ×0.02 (A”-2)
P ₂ −P ₂ ×0.02≦P ₁ ≦P ₂ +P ₂ ×0.02 (A”-3)
B: The above formulae (A"-1), (A"-2), and (A"-3) are not satisfied, but the following formulae (A-1), (A-2), and (A-3) are satisfied: P ₁ - _{P 1} × 0.05 ≦ P ₂ ≦ P ₁ + P ₁ × 0.05 (A-1)
P ₁ - _{P 1} ×0.05≦P ₃ ≦P ₁ +P ₁ ×0.05 (A-2)
P ₂ −P ₂ ×0.05≦P ₁ ≦P ₂ +P ₂ ×0.05 (A-3)
C: The formulae (A-1), (A-2), and (A-3) are not satisfied.

<Haze measurement>
The electromagnetic wave reflective films (optically anisotropic films) obtained in each Example and Comparative Example were measured using a haze meter (HM-150N, manufactured by MURAKAMI COLORLAB) in accordance with JIS K7361-1:2000. The haze value was measured three times for each electromagnetic wave reflective film using a sample obtained by transferring an electromagnetic wave reflective film cut into a size of 50 mm x 50 mm to glass, and placing the sample so that the glass substrate side was the light source side. The haze value was calculated as the average value of the three measurements. "Measured three times" does not mean that the same place is measured three times, but that three different places are measured.

なお、表中の溶剤及びレベリング剤の略語は以下のとおりである。
ＭＥＫ：メチルエチルケトン（沸点８０℃）
ＭＩＢＫ：メチルイソブチルケトン（沸点１１６℃）
ＣＰＮ：シクロペンタノン（沸点１３１℃）
ＥｔＯＡｃ：酢酸エチル（沸点７７℃）
Ｍｅ－ＴＨＦ：２－メチルテトラヒドロフラン（沸点７８℃）
４－Ｍｅ－ＴＨＰ：４－メチルテトラヒドロピラン（沸点１０５℃）

The abbreviations for the solvents and leveling agents in the table are as follows.
MEK: Methyl ethyl ketone (boiling point 80°C)
MIBK: Methyl isobutyl ketone (boiling point 116°C)
CPN: Cyclopentanone (boiling point 131°C)
EtOAc: Ethyl acetate (boiling point 77° C.)
Me-THF: 2-methyltetrahydrofuran (boiling point 78°C)
4-Me-THP: 4-methyltetrahydropyran (boiling point 105°C)

10 Electromagnetic wave reflecting film 20 Support 20' Support 30 Orientation film 100 Laminate

Claims (5)

The composition contains an achiral polymerizable liquid crystal compound having a solid-liquid crystal phase transition temperature of 50° C. to 120° C., a chiral polymerizable compound having a phase transition temperature of 60° C. to 90° C., a photopolymerization initiator , and a solvent ;
the solvent contains 30 mass% or more of a solvent having a boiling point within a range of the phase transition temperature of the chiral polymerizable compound ±20°C based on the total solvent,
The chiral polymerizable compound having a phase transition temperature of 60° C. to 90° C. is selected from at least one selected from the group consisting of compounds represented by the following general formula (2):
A polymerizable cholesteric liquid crystal composition that does not contain a polymerizable liquid crystal compound having a fluorene skeleton.

(In the general formula (2),
L3 and L4 ^each independently represent -O-, -S-, -COO-, -OCO-, or a single bond ^;
A3 and A4 ^each independently represent a 1,4-phenylene group, a 1,4-cyclohexylene group, or a naphthalene-2,6-diyl group ^;
R ³ and R ⁴ each independently represent a group selected from the following general formula (R-2):
General formula (R-2): -L ^r2 -R ^sp2 -Z ²
In general formula (R-2), L ^r2 represents -O-, -S-, -COO-, -OCO-, -OCOO-, or a single bond, R ^sp2 represents an alkylene group having 1 to 20 carbon atoms in which one -CH ₂ - or two or more non-adjacent -CH ₂ - groups may each be independently replaced by -O-, -COO-, or -OCO-, and Z ² represents a group selected from the following formula (Z-1):
Substituents E2 ^and E3 ^each independently represent an alkyl group having 1 to 3 carbon atoms or a halogen atom;
n3 and n4 each independently represent 2 to 3, m1 and m2 each independently represent 0 to 2,
When a plurality of L ³ , L ⁴ , A ³ , and A ⁴ are present, they may be the same or different.

(In formula (Z-1), R ^z is a hydrogen atom, a methyl group, or a trifluoromethyl group.) The polymerizable cholesteric liquid crystal composition according to claim 1, further comprising a non-fluorine-based leveling agent. 3. The polymerizable cholesteric liquid crystal composition according to claim 1, wherein the achiral polymerizable liquid crystal compound is at least one selected from the group consisting of compounds represented by the following general formula (1):

In the general formula (1), Ar represents a 1,4-phenylene group or a naphthalene-2,6-diyl group.
L ¹ and L ² each independently represent -O-, -S-, -COO-, -OCO-, -CH ₂ -CH ₂ -OCO-, -OCO-CH ₂ -CH ₂ -, -CH ₂ -OCO-, -OCO-CH ₂ -, or a single bond;
A ¹ and A ² each independently represent a 1,4-phenylene group, a 1,4-cyclohexylene group, or a naphthalene-2,6-diyl group;
Each of Ar, ^A1 , and ^A2 may be substituted with one or more substituents ^E1 , and the substituents ^E1 are halogen, a nitro group, a cyano group, a tetrazole group, an alkyl group having 1 to 7 carbon atoms, or an alkoxy group having 1 to 7 carbon atoms;
R ¹ and R ² each independently represent a group selected from the following general formula (R-1):
General formula (R-1): -L ^r1 -R ^sp1 -Z ¹
In general formula (R-1), L ^r1 represents -O-, -S-, -COO-, -OCO-, -OCOO-, or a single bond, R ^sp1 represents an alkylene group having 1 to 20 carbon atoms in which one -CH ₂ - or two or more non-adjacent -CH ₂ - groups may each be independently replaced by -O-, -COO-, or -OCO-, or a single bond, and Z ¹ represents a polymerizable functional group.
n1 and n2 each independently represent an integer of 0 to 2, provided that n1+n2 is 1 or more;
When there are a plurality of L ¹ , L ² , A ¹ , and A ² , they may be the same or different. An optically anisotropic film which is a cured film of the polymerizable cholesteric liquid crystal composition according to claim 1 or 2. 3. An electromagnetic wave reflective film which is a cured film of the polymerizable cholesteric liquid crystal composition according to claim 1 or 2 ,
After heating the electromagnetic wave reflective film at 90° C. for 72 hours,
The electromagnetic wave reflective film, wherein the helical pitch of the cholesteric liquid crystal in the cured film of the polymerizable cholesteric liquid crystal composition satisfies the following formulae (A-1), (A-2), and (A-3):
P ₁ - _{P 1} ×0.05≦P ₂ ≦P ₁ +P ₁ ×0.05 (A-1)
P ₁ - _{P 1} ×0.05≦P ₃ ≦P ₁ +P ₁ ×0.05 (A-2)
P ₂ −P ₂ ×0.05≦P ₁ ≦P ₂ +P ₂ ×0.05 (A-3)
(Here, _P1 represents the length of the helical pitch including the position of the first surface of the cured film, _P2 represents the length of the helical pitch including the position of the second surface of the cured film opposite to the first surface, and _P3 represents the length of the helical pitch including the position of the center part of the cured film in the layer thickness direction.)

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