JP2023162737A - Liquid crystal composition and liquid crystal light control element - Google Patents

Abstract

To provide a liquid crystal composition for a smart window that operates autonomously, using solely solar light as an energy source, without using electric energy, and a liquid crystal light control element including the same.SOLUTION: A liquid crystal composition according to an embodiment includes: a non-polymerizable liquid crystal compound (LB) that shows a smectic A phase at room temperature and a chiral nematic phase at temperatures higher than the smectic A phase; and a dye including at least one photoisomer group.SELECTED DRAWING: Figure 1

Description

This embodiment relates to a liquid crystal composition and a liquid crystal light control element.

Liquid crystal materials are not only used for display material elements that display text, images, and videos, as typified by TVs and smartphones, but are also being considered for application in smart windows as dimming elements that adjust the transmission of light. . Smart windows are windows that can control the amount of sunlight that passes through them, and there is growing demand for their use in maintaining a comfortable indoor environment.
On the other hand, a polymer dispersed type (PNM: :Polymer Network liquid crystal material) light control element in which a liquid crystal material is dispersed in a polymer matrix and a polymer dispersed type light control element in which a liquid crystal material is interposed in a polymer network are as follows. , unlike general light control elements, the degree of transmission/scattering of the element can be adjusted. Due to the above features, smart glass and smart windows (SW) for building materials, transportation windows, interior, exterior, private glass (SG), variable projector screens, digital signage, etc. that utilize transmission/scattering light control functions. It is desired to apply it to etc.
With the development of communication technology in recent years, it has become possible to use mobile terminals to control various types of equipment, whether for industrial or home use, so voltage-driven smart glass, smart windows (SW), etc. Light control materials have been proposed to achieve this (for example, Patent Documents 1 to 3).
However, since the above-mentioned light control material for smart windows is voltage-driven, there is a problem that not only manual operation is required during switching, but also the consumption of electrical energy is unavoidable.

Japanese Patent Application Publication No. 6-208107 Japanese Patent Application Publication No. 2007-91850 JP2011-026526A

In view of the above circumstances, it is an object of the present embodiment to provide a liquid crystal composition for a smart window that uses only sunlight as an energy source without using electrical energy, and to provide a liquid crystal composition for a smart window that is autonomously driven. An object of the present invention is to provide a light control element.

As a result of extensive studies, the present embodiment's inventors have found that dyes with photoisomer groups such as azobenzene can be reversibly isomerized in response to light. It is possible to solve the above problems by providing a smart window that uses only sunlight as an energy source and is driven autonomously, and by providing a liquid crystal composition for use in such a smart window. discovered and completed the invention.

That is, the content of the present disclosure includes the following embodiments.
[1] A non-polymerizable liquid crystal compound (LB),
A liquid crystal composition containing a dye having at least one photoisomer group,
A liquid crystal composition, wherein the non-polymerizable liquid crystal compound (LB) exhibits a smectic A phase at room temperature and exhibits a chiral nematic phase at a higher temperature than the smectic A phase.
[2] The liquid crystal composition according to [1], further comprising at least two types of dichroic dyes having different structures from the dye having a photoisomer group.
[3] The liquid crystal composition according to [1] or [2], further containing a chiral compound.
[4] The liquid crystal composition according to any one of [1] to [3], wherein the upper limit temperature of the smectic A phase is 20°C or more and 50°C or less.
[5] The liquid crystal composition according to any one of [1] to [4], further containing a polymerizable compound (MA).
[6] The liquid crystal composition according to [5], further containing a photopolymerization initiator.
[7] A liquid crystal light control element obtained by sandwiching the liquid crystal composition according to any one of [1] to [6] between a pair of substrates.
[8] A liquid crystal light control element containing a polymer obtained from the polymerizable compound (MA) in the liquid crystal composition of [5] or [6].
[9] The liquid crystal light control device according to [7] or [8], wherein the non-polymerizable liquid crystal compound (LB) is vertically aligned on the substrate in a smectic A phase.
[10] The liquid crystal light control device according to any one of [7] to [9], wherein the surface of the substrate is subjected to vertical alignment treatment.
[11] The liquid crystal light control device according to any one of [7] to [9], wherein the substrate does not have a transparent electrode.
[12] The liquid crystal light control device according to any one of [8] to [10], wherein the polymer forms a polymer network.

According to this embodiment, it is possible to provide a smart window that uses only sunlight as an energy source and is driven autonomously without using electrical energy. Furthermore, a liquid crystal composition for use in such smart windows can be provided. Furthermore, a liquid crystal light control element including the liquid crystal composition can be provided.

FIG. 1 is a diagram showing an outline of manufacturing a liquid crystal light control element of an example.

This embodiment will be described in further detail below. Note that this embodiment is not limited to only the embodiment shown below.

(Liquid crystal composition)
A liquid crystal composition of one embodiment of the present embodiment (hereinafter referred to as the present embodiment) contains a non-polymerizable liquid crystal compound (LB) and a dye having at least one type of photoisomer group. The non-polymerizable liquid crystal compound (LB) exhibits a smectic A phase at room temperature, and exhibits a nematic phase at a higher temperature than the smectic A phase.
A gray scale is easier on the human eye than a monochromatic color tone, and from the viewpoint of aesthetics and design, the liquid crystal composition of the present embodiment further includes the photoisomerizable liquid crystal composition in order to adjust the color tone. It is preferable to contain at least two kinds of dichroic dyes having different structures from the dye.
In addition, in order to improve the scattering property in the scattering state of the liquid crystal light control element, it is preferable to exhibit a chiral nematic phase (cholesteric phase). It is preferable to contain a compound.
Further, in order to stabilize the scattering state and transmission state of the liquid crystal light control element, it is preferable that the liquid crystal composition of this embodiment further contains a polymerizable compound (MA). At this time, in order to increase the efficiency of photopolymerization and form a stronger polymer and polymer network, it is preferable that the liquid crystal composition of this embodiment further contains a photopolymerization initiator.

In the liquid crystal composition of this embodiment, by using a non-polymerizable liquid crystal compound (LB) that exhibits a smectic A phase at room temperature, it is possible to align liquid crystal molecules perpendicularly to the substrate when creating a liquid crystal light control element. . When a photoisomerizable dye such as azobenzene is added to this liquid crystal composition, when exposed to light, the azobenzene changes from the trans form to the cis form through photoisomerization, lowering the phase transition temperature of the liquid crystal composition. It becomes a chiral nematic phase, and in particular in the presence of a polymer network, a light scattering state occurs because the refractive index of the liquid crystal molecules and the polymer are different. These two phases allow the liquid crystal light control element to switch between the light transmitting state and the light scattering state, making it suitable as a component of a smart window that can be driven autonomously without applying voltage.

[Non-polymerizable liquid crystal compound (LB)]

The non-polymerizable liquid crystal compound (LB) contained in the liquid crystal composition of this embodiment has an upper limit temperature of smectic A phase of 20°C or more and 50°C or less from the viewpoint of switching drive temperature due to sunlight and heat. The temperature is preferably 30°C or higher and 50°C or lower.

The non-polymerizable liquid crystal compound (LB) contained in the liquid crystal composition of the present embodiment preferably has a nematic phase in a temperature range exceeding the upper limit temperature of the smectic A phase. Further, it is more preferable to have a nematic phase in a temperature range exceeding the upper limit temperature of the smectic A phase and not more than 80°C, and even more preferably not more than 60°C.

The non-polymerizable liquid crystal compound (LB) contained in the liquid crystal composition of this embodiment preferably contains one or more compounds represented by the following general formula (v).

(Compound represented by general formula (v))
The dye compound-containing liquid crystal composition according to the present embodiment is a liquid crystal compound having positive dielectric anisotropy (2≦Δε) at 25° C., a so-called P-type compound, from the viewpoint of driving the liquid crystal with an appropriate voltage. It may contain one or more compounds represented by the following general formula (v).

The dielectric anisotropy (Δε) of the liquid crystal compound is a value extrapolated from the measured value of the dielectric anisotropy of a composition obtained by adding the liquid crystal compound to a dielectrically neutral composition at 25°C. It is.

In the general formula (v), each R ^v1 independently represents an alkyl group having 1 to 20 carbon atoms.

The alkyl group having 1 to 20 carbon atoms is a linear, branched or cyclic alkyl group, and preferably a linear alkyl group.

The number of carbon atoms in the alkyl group having 1 to 20 carbon atoms is preferably 2 to 10, preferably 2 to 6.

One or more -CH ₂ - in the alkyl group may be each independently substituted with -O- and/or -CO-.

Furthermore, one or more -CH ₂ -CH ₂ - in the alkyl group may be each independently substituted with -CH=CH- and/or -C≡C-.

Furthermore, one or more hydrogen atoms in the alkyl group may be each independently substituted with a halogen atom.

Examples of the halogen atom include a fluorine atom, a chlorine atom, and a bromine atom.

However, when the alkyl group is substituted with a predetermined group, the oxygen atoms do not bond directly.

For example, R ^v1 can represent an alkoxy group having 1 to 19 carbon atoms by replacing one -CH ₂ - in the alkyl group with -O-.

The alkoxy group is a linear, branched or cyclic alkoxy group, and preferably a linear alkoxy group.

The number of carbon atoms in the alkoxy group is preferably 2 to 10, preferably 2 to 6.

Furthermore, R ^v1 represents an alkenyl group having 1 to 20 carbon atoms, in which one or more -CH ₂ -CH ₂ - in the alkyl group is replaced with -CH=CH-. be able to.

The alkenyl group is a linear, branched or cyclic alkenyl group, and preferably a linear alkenyl group.

The number of carbon atoms in the alkenyl group is preferably 2 to 10, preferably 2 to 6.

Furthermore, R ^v1 represents an alkynyl group having 1 to 20 carbon atoms, in which one or more -CH ₂ -CH ₂ - in the alkyl group is replaced with -C≡C-. be able to.

The alkynyl group is a linear, branched or cyclic alkynyl group, and preferably a linear alkynyl group.

The number of carbon atoms in the alkynyl group is preferably 2 to 10, preferably 2 to 6.

Furthermore, in R ^v1 , one -CH ₂ - in the alkyl group is substituted with -O-, and one or more -CH ₂ -CH ₂ - are substituted with -CH=CH-. can represent an alkenyloxy group having 1 to 19 carbon atoms.

The alkenyloxy group is a linear, branched or cyclic alkenyloxy group, and preferably a linear alkenyloxy group.

The number of carbon atoms in the alkenyloxy group is preferably 2 to 10, preferably 2 to 6.

Further, R ^v1 can represent a halogenated alkyl group having 1 to 20 carbon atoms, by replacing one or more hydrogen atoms in the alkyl group with a halogen atom.

The halogenated alkyl group is a linear, branched or cyclic halogenated alkyl group, and preferably a linear halogenated alkyl group.

The number of carbon atoms in the halogenated alkyl group is preferably 2 to 10, preferably 2 to 6.

Specific examples of the alkyl group having 1 to 20 carbon atoms (including substituted ones) in R ^v1 include groups represented by formulas (R ^v1 -1) to (R ^v1 -31).

In formulas (R ^v1 -1) to (R ^v1 -31), black dots represent bonds to the ring structure.

Note that R ^v1 is preferably a linear alkyl group having 1 to 6 carbon atoms from the viewpoint of reducing the viscosity of the liquid crystal composition containing the dye compound.

In the general formula (v), R ^v2 represents either an alkyl group having 1 to 20 carbon atoms, a halogen atom, -CN, -OCN or -C≡CCN. R ^v2 preferably represents a halogen atom, -CN, -OCN or -C≡CCN.

Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. Note that R ^v2 is preferably a fluorine atom or -CN from the viewpoint of high light resistance and high solubility of the liquid crystal composition containing a dye compound.

The alkyl group having 1 to 20 carbon atoms in R ^v2 has the same meaning as the alkyl group having 1 to 20 carbon atoms in R ^v2 above. Further, specific examples of the alkyl groups having 1 to 20 carbon atoms (including substituted ones) in R ^v2 include the alkyl groups having 1 to 20 carbon atoms (including substituted ones) in R ^v2 above. Similarly, groups represented by the above formulas (R ^v1 -1) to (R ^v1 -31) can be mentioned.

In general formula (v), A ^v1 and A ^v2 are each independently the following group (a), group (b) and group (c):
(a) 1,4-cyclohexylene group (even if one -CH ₂ - or two or more non-adjacent -CH ₂ -s present in this group is replaced with -O- and/or -S-) good.)
(b) 1,4-phenylene group (one -CH= or two or more non-adjacent -CH= present in this group may be replaced with -N=)
(c) Naphthalene-2,6-diyl group or decahydronaphthalene-2,6-diyl group (one -CH= or two or more non-adjacent -CH present in the naphthalene-2,6-diyl group) = may be replaced with -N=.)
Represents a group selected from the group consisting of.

Furthermore, one or more hydrogen atoms in A ^v1 and A ^v2 may be each independently substituted with a halogen atom.

Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

The substitution position of the halogen atom in A ^v1 and A ^v2 is preferably one of the following formulas (A ^v1/2 -SP-1) to (A ^v1/2 -SP-2).

In the formulas (A ^v1/2 -SP-1) to (A ^v1/2 -SP-2), S ^v1/2 each independently represents a halogen atom, and the white dots represent bonds to R ^v1 or Z ^v1 . , and the black dots represent the bond to Z ^v1 or R ^v2 .

Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

More specifically, A ^v1 and A ^v2 preferably represent any of the following formulas (A ^v1/2 -1) to (A ^v1/2 -5).

In the formulas (A ^v1/2 -1) to (A ^v1/2 -5), the white dots represent the bond to R ^v1 or Z ^v1 , and the black dots represent the bond to Z ^v1 or R ^v2 .

In the general formula (v), Z ^v1 and Z ^v2 each independently represent either a single bond or an alkylene group having 1 to 20 carbon atoms.

The alkylene group is a linear, branched or cyclic alkylene group, and preferably a linear alkylene group.

The number of carbon atoms in the alkylene group is preferably 2 to 10, preferably 2 to 6.

One or more -CH ₂ - in the alkylene group are each independently substituted with -O-, -CH(CH ₃ )-, -CO- and/or -CF ₂ -. Good too.

Furthermore, one or more -CH ₂ -CH ₂ - in the alkylene group are each independently -CH=CH-, -CF=CH-, -CH=CF-, -CF=CF -, -CH=C(CH ₃ )-, -C(CH ₃ )=CH-, -CH=N-, -N=CH-, -N=N- and/or -C≡C- It's okay.

However, when the alkylene group is substituted with a predetermined group, the oxygen atoms do not bond directly.

Specific examples of alkylene groups having 1 to 20 carbon atoms (including substituted ones) include groups represented by formulas (Z ^v1 -1) to (Z ^v1 -24).

In the formulas (Z ^v1 -1) to (Z ^v1 -24), the white dots represent the bond to A ^v1 or A ^v2 , and the black dots represent the bond to A ^v2 .

Note that Z ^vi1 may be a single bond, -CO-O-, -O-CO-, or a linear alkylene group having 1 to 6 carbon atoms, from the viewpoint of high light resistance of the liquid crystal composition containing the dye compound. is preferred.

n ^v1 represents an integer from 1 to 3.

When a plurality of A ^v2 and Z ^v1 exist, they may be the same or different.

However, among the compounds represented by general formula (v), compounds represented by general formulas (ii) and (iii) (including subordinate concepts) are excluded.

The compound represented by the general formula (v) is preferably a compound represented by the following general formulas (v-1) to (v-3).

In general formulas (v-1) to (v-6), R ^v1 , R ^v2 , Z ^v1 , Z ^v2 , A ^v1 and A ^v2 are R ^v1 , R ^v2 , Z ^v1 in the above general formula (v) , Z ^v2 , A ^v1 and A ^v2 each represent the same meaning, and the preferred groups also represent the same thing.

In general formulas (v-1) to (v-6), Z ^v1-2 and Z ^v1-3 each independently represent the same meaning as Z ^v1 in the above general formula (v), and are preferred groups. also represent the same thing.

In general formulas (v-1) to (v-6), A ^v2-2 and A ^v2-3 each independently represent the same meaning as A ^v1 in the above general formula (v), and are preferred groups. also represent the same thing.

The compound represented by the general formula (v-1) is preferably a compound represented by the following general formulas (v-1-1) to (v-1-10).

In the general formulas (v-1-1) to (v-1-10), R ^v1 and R ^v2 each have the same meaning as R ^v1 and R ^v2 in the above general formula (v), and the preferred groups are also the same. represent something.

In the general formulas (v-1-1) to (v-1-10), S ^v1/2 each independently represents a halogen atom.

Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

The compound represented by the general formula (v-1-1) is preferably a compound represented by the following structural formulas (v-1-1.1) to (v-1-1.4).

The compound represented by the general formula (v-1-2) is preferably a compound represented by the following structural formula (v-1-2.1).

The compound represented by the general formula (v-1-3) is preferably a compound represented by the following structural formulas (v-1-3.1) to (v-1-3.4).

The compound represented by the general formula (v-1-4) is preferably a compound represented by the following structural formulas (v-1-4.1) to (v-1-4.4).

The compound represented by the general formula (v-1-5) is preferably a compound represented by the following structural formula (v-1-5.1).

The compound represented by the general formula (v-1-6) may be a compound represented by the following structural formulas (v-1-6.1) to (v-1-6.2). preferable.

The compound represented by the general formula (v-1-7) is preferably a compound represented by the following structural formula (v-1-7.1).

The compound represented by the general formula (v-1-8) is preferably a compound represented by the following structural formula (v-1-8.1).

The compound represented by the general formula (v-1-9) is preferably a compound represented by the following structural formula (v-1-9.1).

The compound represented by the general formula (v-1-10) is preferably a compound represented by the following structural formula (v-1-10.1).

The compound represented by the general formula (v-2) is preferably a compound represented by the following general formulas (v-2-1) to (v-2-5).

In the general formulas (v-2-1) to (v-2-6), R ^v1 and R ^v2 each have the same meaning as R ^v1 and R ^v2 in the above general formula (v), and the preferred groups are also the same. represent something.

In the general formulas (v-2-1) to (v-2-5), S ^v1/2 each independently represents a halogen atom.

Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

The compound represented by the general formula (v-2-1) is preferably a compound represented by the following structural formula (v-2-1.1).

The compound represented by the general formula (v-2-2) is preferably a compound represented by the following structural formulas (v-2-2.1) to (v-2-2.2).

The compound represented by the general formula (v-2-3) is preferably a compound represented by the following structural formula (v-2-3.1).

The compound represented by the general formula (v-2-4) is preferably a compound represented by the following structural formulas (v-2-4.1) to (v-4-4.2).

The compound represented by the general formula (v-2-5) is preferably a compound represented by the following structural formula (v-2-5.1).

The compound represented by the general formula (v-2-6) is preferably a compound represented by the following structural formulas (v-2-6.1) to (v-2-6.4).

The compound represented by the general formula (v-3) is preferably a compound represented by the following general formulas (v-3-1) to (v-3-2).

In the general formulas (v-3-1) to (v-3-2), R ^v1 and R ^v2 each have the same meaning as R ^v1 and R ^v2 in the above general formula (v), and the preferred groups are also the same. represent something.

In general formulas (v-3-1) to (v-3-2), S ^v1/2 each independently represents a halogen atom.

Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

The compound represented by the general formula (v-3-1) is preferably a compound represented by the following structural formulas (v-3-1.1) to (v-3-1.2).

The compound represented by the general formula (v-3-1) is preferably a compound represented by the following structural formulas (v-3-2.1) to (v-3-2.2).

The compound represented by the general formula (v-4) is preferably a compound represented by the following general formulas (v-4-1) to (v-4-5).

In the general formulas (v-4-1) to (v-1-5), R ^v1 and R ^v2 each have the same meaning as R ^v1 and R ^v2 in the above general formula (v), and the preferred groups are also the same. represent something.

In general formulas (v-4-1) to (v-4-3), S ^v1/2 each independently represents a halogen atom.

Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

The compound represented by the general formula (v-4-4) is preferably a compound represented by the following structural formulas (v-4-4.1) to (v-4-4.7).

General formula (v); preferably, general formulas (v-1) to (v-5); more preferably, general formulas (v-1-1) to (v-1-10), general formula (v-2- 1) to (v-2-6), general formulas (v-3-1) to (v-3-2), general formulas (v-4-1) to (v-4-5); more preferably, Structural formula (v-1-1.1) ~ (v-1-1.4), structural formula (v-1-2.1), structural formula (v-1-3.1) ~ (v-1 -3.4), Structural formula (v-1-4.1) to (v-1-4.5), Structural formula (v-1-5.1), Structural formula (v-1-6.1) ) ~ Structural formula (v-1-6.2), Structural formula (v-1-7.1), Structural formula (v-1-8.1), Structural formula (v-1-9.1), Structural formula (v-1-10.1), structural formula (v-2-1.1), structural formula (v-2-2.1) to (v-2-2.2), structural formula (v -2-3.1), Structural formula (v-2-4.1) to (v-2-4.2), Structural formula (v-2-5.1), Structural formula (v-2-6) .1) ~ (v-2-6.4), structural formula (v-3-1.1) ~ (v-3-1.2), structural formula (v-3-2.1) ~ (v -3-2.2), among the liquid crystal compounds represented by structural formulas (v-4-4.1) to (v-4-4.7), the types used in the liquid crystal composition are one or Two or more types, preferably 1 to 6 types, preferably 1 to 5 types, preferably 1 to 4 types, preferably 2 to 4 types.

Among the liquid crystal compounds represented by general formula (v-1), general formula (v-2), and general formula (v-4), one or more types, preferably two or more types, are used in the liquid crystal composition. It is preferable to use 1 to 6 types, preferably 1 to 5 types, preferably 1 to 4 types, and preferably 2 to 4 types.
Among the liquid crystal compounds represented by general formula (v-1), the number of types used in the liquid crystal composition is two or more, preferably 2 to 6, preferably 2 to 5, and preferably 2 to 4. Among the liquid crystal compounds represented by general formula (v-2), the number of types used in the liquid crystal composition is one or two or more, preferably one to three, more preferably one or two. And among the liquid crystal compounds represented by general formula (v-4), the number of types used in the liquid crystal composition is one or more, preferably one to three, more preferably one to two. More preferably, it is a seed.

Among the liquid crystal compounds represented by general formula (v-1-4), general formula (v-2-6), and general formula (v-4-4), one type or It is preferable that there are two or more types, preferably 1 to 6 types, preferably 1 to 5 types, preferably 1 to 4 types, and preferably 2 to 4 types.
Among the liquid crystal compounds represented by general formula (v-1-4), the number of types used in the liquid crystal composition is 2 or more, preferably 2 to 6, preferably 2 to 5, preferably 2 to 4. Among the liquid crystal compounds that are seeds and represented by the general formula (v-2-6), the types used in the liquid crystal composition are one or more, preferably one to three, more preferably Among the liquid crystal compounds represented by the general formula (v-4-4), the number of types used in the liquid crystal composition is one or two or more, preferably one to three, More preferably, it is one or two types.

Structural formula (v-1-4.1) to (v-1-4.5), structural formula (v-2-6.1) to (v-2-6.4), structural formula (v-4 Among the liquid crystal compounds represented by -4.1) to (v-4-4.7), the number of types used in the liquid crystal composition is one or two or more, preferably 1 to 6, preferably 1. -5 types, preferably 1-4 types, preferably 2-4 types.
Among the liquid crystal compounds represented by structural formulas (v-1-4.1) to (v-1-4.5), the number of types used in the liquid crystal composition is two or more, preferably two to six, Preferably 2 to 5 types, preferably 2 to 4 types, and among the liquid crystal compounds represented by structural formulas (v-2-6.1) to (v-2-6.4), liquid crystal The types used in the composition are one or more types, preferably 1 to 3 types, more preferably 1 to 2 types, and have structural formulas (v-4-4.1) to (v-4- Among the liquid crystal compounds represented by 4.7), the number of types used in the liquid crystal composition is preferably one or two or more, preferably one to three, more preferably one or two.

In 100% by mass of the liquid crystal composition, general formula (v); preferably general formulas (v-1) to (v-5); more preferably general formulas (v-1-1) to (v-1-10) ), general formulas (v-2-1) to (v-2-6), general formulas (v-3-1) to (v-3-2), general formulas (v-4-1) to (v -4-5); More preferably, structural formulas (v-1-1.1) to (v-1-1.4), structural formula (v-1-2.1), structural formula (v-1- 3.1) ~ (v-1-3.4), Structural formula (v-1-4.1) ~ (v-1-4.5), Structural formula (v-1-5.1), Structure Formula (v-1-6.1) ~ Structural formula (v-1-6.2), Structural formula (v-1-7.1), Structural formula (v-1-8.1), Structural formula ( v-1-9.1), structural formula (v-1-10.1), structural formula (v-2-1.1), structural formula (v-2-2.1) to (v-2- 2.2), Structural formula (v-2-3.1), Structural formula (v-2-4.1) to (v-2-4.2), Structural formula (v-2-5.1) , Structural formula (v-2-6.1) ~ (v-2-6.4), Structural formula (v-3-1.1) ~ (v-3-1.2), Structural formula (v- Lower limit of total content of compounds represented by 3-2.1) to (v-3-2.2) and structural formulas (v-4-4.1) to (v-4-4.7) is preferably 1% by mass or more, preferably 3% by mass or more, and preferably 5% by mass or more.

In 100% by mass of the liquid crystal composition, general formula (v); preferably general formulas (v-1) to (v-5); more preferably general formulas (v-1-1) to (v-1-10) , general formulas (v-2-1) to (v-2-6), general formulas (v-3-1) to (v-3-2), general formulas (v-4-1) to (v- 4-5); More preferably, structural formulas (v-1-1.1) to (v-1-1.4), structural formula (v-1-2.1), structural formula (v-1-3 .1) ~ (v-1-3.4), structural formula (v-1-4.1) ~ (v-1-4.5), structural formula (v-1-5.1), structural formula (v-1-6.1) ~ Structural formula (v-1-6.2), Structural formula (v-1-7.1), Structural formula (v-1-8.1), Structural formula (v -1-9.1), Structural formula (v-1-10.1), Structural formula (v-2-1.1), Structural formula (v-2-2.1) to (v-2-2 .2), Structural formula (v-2-3.1), Structural formula (v-2-4.1) to (v-2-4.2), Structural formula (v-2-5.1), Structural formula (v-2-6.1) ~ (v-2-6.4), structural formula (v-3-1.1) ~ (v-3-1.2), structural formula (v-3 -2.1) ~ (v-3-2.2), the upper limit of the total content of compounds represented by structural formulas (v-4-4.1) ~ (v-4-4.7) is , preferably 99.5% by mass or less, preferably 99% by mass or less, and preferably 98% by mass or less.

In 100% by mass of the liquid crystal composition, general formula (v); preferably general formulas (v-1) to (v-5); more preferably general formulas (v-1-1) to (v-1-10) ), general formulas (v-2-1) to (v-2-6), general formulas (v-3-1) to (v-3-2), general formulas (v-4-1) to (v -4-5); More preferably, structural formulas (v-1-1.1) to (v-1-1.4), structural formula (v-1-2.1), structural formula (v-1- 3.1) ~ (v-1-3.4), Structural formula (v-1-4.1) ~ (v-1-4.5), Structural formula (v-1-5.1), Structure Formula (v-1-6.1) ~ Structural formula (v-1-6.2), Structural formula (v-1-7.1), Structural formula (v-1-8.1), Structural formula ( v-1-9.1), structural formula (v-1-10.1), structural formula (v-2-1.1), structural formula (v-2-2.1) to (v-2- 2.2), Structural formula (v-2-3.1), Structural formula (v-2-4.1) to (v-2-4.2), Structural formula (v-2-5.1) , Structural formula (v-2-6.1) ~ (v-2-6.4), Structural formula (v-3-1.1) ~ (v-3-1.2), Structural formula (v- The total content of compounds represented by 3-2.1) to (v-3-2.2) and structural formulas (v-4-4.1) to (v-4-4.7) is 10 It is preferably from 100% by mass, more preferably from 20 to 100% by mass, even more preferably from 30 to 100% by mass.

In 100% by mass of the liquid crystal composition, the total content of the liquid crystal compound represented by general formula (v-1) is preferably 10 to 100% by mass, more preferably 20 to 100% by mass. , more preferably 30 to 100% by mass; the total content of the liquid crystal compound represented by general formula (v-2) is preferably 0 to 40% by mass, and 0 to 30% by mass. is more preferable, and even more preferably 0 to 20% by mass; the total content of the liquid crystal compound represented by general formula (v-4) is preferably 10 to 100% by mass, and 20 to 100% by mass. It is more preferably 30% to 100% by mass, and even more preferably 30 to 100% by mass.

In 100% by mass of the liquid crystal composition, the total content of the liquid crystal compound represented by general formula (v-1-4) is preferably 10 to 100% by mass, and preferably 20 to 100% by mass. More preferably, the content is from 30 to 100% by mass; the total content of the liquid crystal compound represented by general formula (v-2-6) is preferably from 0 to 40% by mass, and from 0 to 30% by mass. The total content of the liquid crystal compound represented by the general formula (v-4-4) is preferably 0 to 40% by mass, more preferably 0 to 20% by mass. The content is preferably 0 to 30% by mass, more preferably 0 to 20% by mass.

In 100% by mass of the liquid crystal composition, the total content of liquid crystal compounds represented by structural formulas (v-1-4.1) to (v-1-4.5) shall be 10 to 100% by mass. is preferably 20 to 100% by mass, even more preferably 30 to 100% by mass; with structural formulas (v-2-6.1) to (v-2-6.4)) The total content of the liquid crystal compounds represented is preferably 0 to 40% by mass, more preferably 0 to 30% by mass, even more preferably 0 to 20% by mass; structural formula (v The total content of the liquid crystal compounds represented by -4-4.1) to (v-4-4.7) is preferably 0 to 40% by mass, more preferably 0 to 30% by mass. It is preferably 0 to 20% by mass, and more preferably 0 to 20% by mass.

The liquid crystal composition of the present embodiment preferably exhibits a smectic A phase and further exhibits a nematic phase on the high temperature side, and in order to exhibit this, it is necessary to appropriately adjust a plurality of compounds having different alkyl chains.
For the development of a smectic A phase, a compound having an alkyl chain length of 6 to 20 carbon atoms is preferred, and for a nematic phase, a compound having an alkyl chain length of 1 to 5 carbon atoms is preferred.

General formula (v); preferably, general formulas (v-1) to (v-5); more preferably, general formulas (v-1-1) to (v-1-10), general formula (v-2- 1) to (v-2-6), general formulas (v-3-1) to (v-3-2), general formulas (v-4-1) to (v-4-5); more preferably, Structural formula (v-1-1.1) ~ (v-1-1.4), structural formula (v-1-2.1), structural formula (v-1-3.1) ~ (v-1 -3.4), Structural formula (v-1-4.1) to (v-1-4.5), Structural formula (v-1-5.1), Structural formula (v-1-6.1) ) ~ Structural formula (v-1-6.2), Structural formula (v-1-7.1), Structural formula (v-1-8.1), Structural formula (v-1-9.1), Structural formula (v-1-10.1), structural formula (v-2-1.1), structural formula (v-2-2.1) to (v-2-2.2), structural formula (v -2-3.1), Structural formula (v-2-4.1) to (v-2-4.2), Structural formula (v-2-5.1), Structural formula (v-2-6) .1) ~ (v-2-6.4), structural formula (v-3-1.1) ~ (v-3-1.2), structural formula (v-3-2.1) ~ (v -3-2.2) and the compounds represented by structural formulas (v-4-4.1) to (v-4-4.7) can be synthesized using known synthesis methods.
An example of the non-polymerizable liquid crystal compound (LB) of this embodiment more preferably includes the following four types of host liquid crystals.

As one specific example of the non-polymerizable liquid crystal compound (LB) of this embodiment, for example, three types of liquid crystal compounds 8CB, 7CB, and 5CCB shown below can be mentioned.
4-cyano-4'-n-octylbiphenyl (8CB),
4-cyano-4'-n-heptylbiphenyl (7CB),
trans-4'- (4-amylcyclohexyl)biphenyl-4-carbonitrile (5CCB)

[Dye with photoisomer group]
A dye having a photoisomerization group is a dye having a substituent that causes a photoisomerization reaction. The dye having a photoisomer group of this embodiment is not particularly limited as long as it has the property of causing a photoisomerization reaction, but it has dichroism, which causes absorption to vary depending on the direction of polarization, In addition, it is preferable that the material undergoes an isomerization reaction upon irradiation with light. This is because by causing isomerization of the reaction sites oriented in the polarization direction of the photoisomerization-reactive compound having such characteristics, anisotropy can be easily imparted to the light control material described below.
In addition to such dichroic properties, the phase transition behavior of the composition can also be changed by photoisomerization. By using photoisomerization as a driving force, it is possible to produce a light control element of this embodiment in which the transmittance changes before and after irradiation with light such as sunlight. The feature of this embodiment is that the phase transition behavior in the transparent state (before sunlight irradiation) is the phase transition behavior in the normal stable state, and that the transition to a phase on the high temperature side is possible due to the photoisomerization reaction accompanying light irradiation.
The photoisomerization reaction that produces such a photoisomerization-reactive compound is preferably a cis-trans isomerization reaction. This is because light irradiation increases the amount of either the cis isomer or the trans isomer, thereby imparting a change in light transmittance to the light control material.

Specific examples of dyes having such photoisomeric groups include compounds having a cis-trans isomerization-reactive skeleton such as an azobenzene skeleton or a stilbene skeleton.
In this case, the number of cis-trans isomerization-reactive skeletons contained in the molecule may be one or two or more, but it is preferable to use one because it makes it easier to control the alignment of the liquid crystal. It is preferable that

The cis-trans isomerization-reactive skeleton may have a substituent to further enhance interaction with liquid crystal molecules. The substituent is not particularly limited as long as it can enhance the interaction with liquid crystal molecules and does not hinder the orientation of the cis-trans isomerization-reactive skeleton; for example, a carboxyl group, a sulfonic acid group, etc. Examples include sodium group and hydroxyl group. These structures can be appropriately selected depending on the type of liquid crystal used.
In addition, in addition to the cis-trans isomerization-reactive skeleton in the molecule, photoisomerization-reactive compounds have many π electrons such as aromatic hydrocarbon groups in order to enhance the interaction with liquid crystal molecules. The cis-trans isomerization-reactive skeleton and the aromatic hydrocarbon group may be bonded via a bonding group. The bonding group is not particularly limited as long as it can enhance the interaction with liquid crystal molecules, for example, -COO-, -OCO-, -O-, -C≡C-, -CH ₂ -CH _2- , -CH ₂ O-, -OCH ₂ -, and the like.

The dye having a photoisomer group of this embodiment is preferably a compound having an azobenzene skeleton in the molecule. This is because the azobenzene skeleton contains a large number of π electrons and therefore has high interaction with liquid crystal molecules, making it particularly suitable for controlling the alignment of liquid crystals.

The reason why a change in light transmittance can be imparted to a light control material by the azobenzene skeleton causing a photoisomerization reaction will be explained below. First, when the azobenzene skeleton is irradiated with light, the azobenzene skeleton in the trans form changes to the cis form, as shown in the following formula.

This transsis optical phase transition lowers the phase transition temperature of the liquid crystal composition. As a result, for example, in this embodiment, the smectic A phase before light irradiation changes to the chiral nematic phase after light irradiation under the same environmental temperature. In this embodiment, by utilizing this phenomenon, the light transmitting state and the light scattering state of the liquid crystal light control element are switched.
Among such compounds having an azobenzene skeleton in the molecule, monomolecular compounds include, for example, compounds represented by the following general formulas (w-1) to (w-2).

In the general formulas (w-1) to (w-2), R ^w1 represents either a halogen atom, -CN, -O ₂ N, -OCN, -C≡CCN, or -COOMe. R ^w1 preferably represents any one of -CN, -O ₂ N, and -COOMe, and more preferably represents -CN.

Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. R ^w1 preferably represents either -CN or -O ₂ N, more preferably -CN.

In the general formulas (w-1) to (w-2), R ^w2 each independently represents either an alkyl group having 1 to 20 carbon atoms or -NMe ₂ .

The alkyl group having 1 to 20 carbon atoms is a linear, branched or cyclic alkyl group, and preferably a linear alkyl group.

The number of carbon atoms in the alkyl group having 1 to 20 carbon atoms is preferably 2 to 10, preferably 4 to 10.

The compounds represented by the general formula (w-1) may be compounds Azo-1 and Azo-2 represented by the following structural formulas (w-1-1) to (w-1-2), respectively. preferable. (Azo-2:1-octyl-4-[4-(4-cyano-phenylazo)phenyl]piperazine)

The compound represented by the general formula (w-2) is preferably a compound Azo-3 represented by the following structural formula (w-2-1).

A preferred proportion of the dye having a photoisomeric group in this embodiment is in the range of 1% to 25%, based on the liquid crystal composition. A more preferred ratio is in the range of 2% to 20%. A particularly preferred proportion is in the range 3% to 15%.

In 100% by mass of the liquid crystal composition, the upper limit of the total content of the dye having a photoisomer group of this embodiment is preferably 25% by mass or less from the viewpoint of precipitation, and preferably 20% by mass or less. The content is more preferably 15% by mass or less.

In 100% by mass of the liquid crystal composition, the lower limit of the total content of the dye having a photoisomer group of this embodiment is preferably 1% by mass or more from the viewpoint of drivability as a light control element, and 2% by mass. % or more, and even more preferably 3% by mass or more.

[Dichroic dye]
The dichroic dye of this embodiment is preferably a black (or dark-colored) dichroic dye. Black color is prepared by mixing cyan, magenta, and yellow dichroic dyes. At least two dyes are mixed. Preferably, two, three, four, five or six dyes are mixed. Particularly preferably, three or four dyes are mixed.

Such dichroic dyes have at least some of the characteristics described below. a) The dye molecules are linear. b) In the center of the molecule, there is a skeleton unique to dichroic dyes, such as a benzothiadiazole ring or a diketopyrrolopyrrole ring. c) The benzene ring and thiophene ring that constitute the molecule together with the unique skeleton are located on the same plane. d) The side chain is alkyl or alkoxy. e) It has a conjugated double bond in the center.

Examples of the dichroic dye of this embodiment include benzothiadiazoles, diketopyrrolopyrroles, azomethine compounds, and methine compounds. Pounds), anthraquinones, merocyanates merocyanines, naphthoquinones, tetrazines, pyrromethenes, and rylenes such as perylenes and terrylenes. enes). Preferred dichroic dyes are benzothiadiazoles, diketopyrrolopyrroles, azo compounds, anthraquinones, and rylenes. Particularly preferred dichroic dyes are benzothiadiazoles, diketopyrrolopyrroles, azo compounds, and rylenes. For example, benzothiadiazole means a dichroic dye having a benzothiadiazole ring.

Specific examples of the dichroic dye of this embodiment include a cyan dye represented by the following formula, an anthraquinone derivative dye (cyan dye, M-137) manufactured by Mitsui Toatsu, etc.

The types of dichroic dyes of this embodiment used in the liquid crystal composition of this embodiment are one or more, preferably 1 to 5, preferably 1 to 4, and preferably 1 to 3.
[0125]
A preferred proportion of dichroic dye of this embodiment ranges from 1% to 25%, based on the liquid crystal composition. A more preferred ratio is in the range of 2% to 20%. A particularly preferred proportion is in the range 3% to 15%.

In 100% by mass of the liquid crystal composition, the upper limit of the total content of the dichroic dye of this embodiment is preferably 20% by mass or less from the viewpoint of precipitation, and preferably 15% by mass or less, It is preferably 10% by mass or less.

In 100% by mass of the liquid crystal composition, the lower limit of the amount of the dichroic dye added in this embodiment is preferably 0.1 part by mass or more from the viewpoint of designability and designability, and 1 part by mass or more. It is more preferable that the amount is at least 2 parts by mass, and even more preferably 2 parts by mass or more.

The amount of the dichroic dye of this embodiment added to 100 parts by mass of the liquid crystal composition containing no dye compound and additives is preferably 0.1 to 20 parts by mass, and 0.5 to 15 parts by mass. The amount is preferably from 1 to 10 parts by mass.

[Chiral compound]
The chiral compound used in this embodiment can be used to impart various functions to the polymer dispersed liquid crystal light control element of this embodiment. Such a chiral compound is not particularly limited, but it can be used within a range that does not impair the electro-optic properties and adhesion of the liquid crystal light control element. Specifically, for example, cholesterol pelargonic acid, cholesterol stearate, which has a cholesteryl group as a chiral group, "CB-15" and "C-15" manufactured by BDH, which have a 2-methylbutyl group as a chiral group, and Merck "S-1082" manufactured by Chisso, "CM-19", "CM-20", "CM" manufactured by Chisso, "S-811" manufactured by Merck which has a 1-methylheptyl group as a chiral group, "S-811" manufactured by Chisso "CM-21" and "CM-22" manufactured by BASF, "LC756" of BASF, which has an isosorbide skeleton as a chiral group, Japanese Patent Publication No. 2009-515818, Japanese Patent Application Publication No. 2010-90108, Japanese Patent Application Publication No. 2013-87109 Examples include polymerizable chiral compounds shown in Japanese Patent Publications and the like.
When containing a chiral compound, the thickness (d) of the obtained polymer divided by the helical pitch (P) in the polymer (d/ P) is preferably added in an amount of 0.1 to 100, more preferably 0.1 to 20.
The content of the chiral compound is preferably as small as possible to obtain a desired helical pitch in order to bring out the characteristics of the liquid crystal composition. The content of the chiral compound is preferably 1 to 20% by mass, and preferably 2 to 15% by mass, based on 100% by mass of the total amount of non-polymerizable liquid crystal compounds (LB) used in the liquid crystal composition of the present embodiment. It is more preferable that there be.

[Polymerizable compound (MA)]
The polymerizable compound (MA) has a polyfunctional (meth)acrylate oligomer having a weight average molecular weight of 1500 or more as a first component, and a cyclic monofunctional polymer represented by the following general formula (ii) as a second component. The third component is a mesogenic polymerizable compound represented by the following general formula (P), and the fourth component is a polyfunctional compound having a weight average molecular weight of less than 1500 and represented by the following general formula (ii). As the polymerizable oligomer, the polyfunctional polymerizable monomer, and the fifth component, it is preferable to contain one or more of the chain monofunctional polymerizable compounds represented by the general formula (v) described below.
The polymerizable compound (MA) is particularly preferably a mesogenic polymerizable compound represented by the general formula (P), which is the third component, from the viewpoint of solubility and morphology of the polymer network in the liquid crystal composition. However, it is not limited to this.
In the liquid crystal composition of this embodiment, when the polymerizable compound (MA) is included, the weight ratio (LB/MA) of the non-polymerizable liquid crystal compound (LB) and the polymerizable compound (MA) is 99/1. The range is preferably from 97/3 to 70/30, more preferably from 95/5 to 70/30. Each component will be specifically explained below.

[First component]
The first component, the polyfunctional (meth)acrylate oligomer, is an important compound for introducing a crosslinked structure into the polymer network structure and for obtaining good adhesion. Among the polyfunctional (meth)acrylate oligomers, bifunctional acrylate oligomers are preferred. Furthermore, in order to emphasize adhesion to the substrate, the first component should be one or more selected from the group consisting of urethane (meth)acrylate oligomers and polyester (meth)acrylate oligomers. is preferred, and urethane-based acrylate oligomers are even more preferred. Urethane-based acrylate oligomers include polyester-based and polyether-based oligomers, but polyether-based oligomers are preferred. As for the molecular weight, the weight average molecular weight is 1,500 or more, preferably 1,500 to 60,000, more preferably 1,800 to 40,000, and even more preferably 2,000 to 30,000. This is because if the molecular weight is too small, the degree of curing shrinkage will increase due to the increase in crosslinking density caused by the increase in (meth)acrylic groups contained in one molecule, and the adhesion will deteriorate; This is because if the distance between the crosslinks is large, the distance between the crosslinks becomes long, the gap becomes large, and it becomes easier to take in the liquid crystal, thereby reducing the scattering property as a polymer dispersed liquid crystal. In other words, if the polymer is left in a high temperature environment, the polymer will absorb the liquid crystal, resulting in a significant change in properties. In addition, if the molecular weight is large, the degree of decrease in the transition point Tnm of a polymer dispersed liquid crystal due to the addition of a polymerizable compound will be small, and in order to keep Tnm below room temperature, a material with a low Tni of the liquid crystal composition itself must be used. As a result, a problem arises in that the operating temperature range becomes narrower.
Moreover, in this embodiment, the number average molecular weight (Mn) and the weight average molecular weight (Mw) are values converted to polystyrene based on GPC measurement. Note that the GPC measurement conditions are as follows.

[GPC measurement conditions]
Measuring device: “HLC-8320 GPC” manufactured by Tosoh Corporation
Column: Guard column “SuperHZ-L” manufactured by Tosoh Corporation + “SuperHZ2000” manufactured by Tosoh Corporation x 3 + “TSuperHZM-M” manufactured by Tosoh Corporation
Detector: Built-in RI detector Data processing: “EcoSEC-WorkStation Ver2.01” manufactured by Tosoh Corporation
Measurement conditions: Column temperature: 40° C., developing solvent: tetrahydrofuran, flow rate: 1.0 ml/min Standard: Monodisperse polystyrene with a known molecular weight was used in accordance with the device measurement manual.

A polyfunctional urethane (meth)acrylate oligomer is obtained by reacting a hydroxyl group-containing acrylate with a polyol and a polyisocyanate. Examples of the polyol include polyether polyol, polyester polyol, polycaprolactone polyol, polycarbonate polyol, polybutadiene polyol, and the like. Examples of the polyether polyol include polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and the like.
Examples of polyisocyanates include 2,4- and 2,6-tolylene diisocyanate (TDI), orthotoluidine diisocyanate (TODI), naphthylene diisocyanate (NDI), xylylene diisocyanate (XDI), 4,4'-diphenylmethane diisocyanate ( MDI), methylene bis(4-cyclohexyl isocyanate), xylylene diisocyanate, hydrogenated xylylene diisocyanate, hexamethylene diisocyanate, transcyclohexane 1,4-diisocyanate, 1,6,11-undecane triisocyanate, 1,8-diisocyanate-4 -Isocyanate methyl octane, 1,3,6-hexamethylene triisocyanate, bicycloheptane triisocyanate, trimethylhexamethylene diisocyanate, dicyclopentadiene diisocyanate, norbornene diisocyanate, isophorone diisocyanate, and carbodiimide-modified MDI, polymethylene polyphenylisocyanate, polymeric poly Examples include isocyanates.

Examples of hydroxyl group-containing (meth)acrylates include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and polypropylene glycol mono(meth)acrylate. ) acrylate, 1,4-cyclohexanedimethanol monoacrylate, mono(meth)acrylate modified with ε-caprolactone, and the like.

Specifically, aliphatic urethane (meth)acrylates, aromatic urethane (meth)acrylates, and polyurethane diacrylate oligomers are preferred, and the polyols used are preferably polyether polyols, polyester polyols, and polycaprolactone polyols; polyether polyols, Polyester polyol is particularly preferred, and the polyisocyanate used is preferably a polyisocyanate having a cyclic structure, particularly preferably a polyisocyanate having an alicyclic structure. More specifically, orthotoluidine diisocyanate (TODI), methylene bis(4-cyclohexyl isocyanate), xylylene diisocyanate, hydrogenated xylylene diisocyanate, transcyclohexane 1,4-diisocyanate, 1,6,11-undecane triisocyanate, bicyclo Heptane triisocyanate, dicyclopentadiene diisocyanate, norbornene diisocyanate, isophorone diisocyanate, carbodiimide-modified MDI are preferred, methylene bis(4-cyclohexyl isocyanate), xylylene diisocyanate, hydrogenated xylylene diisocyanate, transcyclohexane 1,4-diisocyanate, 1,6 , 11-undecane triisocyanate, bicycloheptane triisocyanate, dicyclopentadiene diisocyanate, norbornene diisocyanate, and isophorone diisocyanate are particularly preferred.

The hydroxyl group-containing (meth)acrylates used include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 1,4- Cyclohexane dimethanol monoacrylate, mono(meth)acrylate modified with ε-caprolactone are preferred, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 4- Particularly preferred is hydroxybutyl (meth)acrylate.

Further, a compound represented by the following general formula (i-1) is also preferred.

(In the formula, X ⁱ¹ each independently represents a hydrogen atom or a methyl group, B ⁱ¹ represents an alkyl group having 1 to 4 carbon atoms, and one or more -CH ₂ - in the alkyl group It may be substituted with an oxygen atom, -CO-, -COO-, -OCO-, b represents 1 to 20, and B ² represents the following (i-2) to (i-6), respectively. May be used alone or in combination,

B ³ is a group selected from the following general formulas (i-7), (i-8), or (i-9), and each may be used alone or in combination. )

(In the formula, X ⁱ² represents a hydrogen atom or a methyl group, X ⁱ³ represents an alkyl group having 1 to 9 carbon atoms,
Y ⁵ represents an alkylene group having 1 to 15 carbon atoms, a divalent aromatic group, or a divalent alicyclic hydrocarbon group,
Y ³ and Y ⁴ represent a hydrogen atom or a methyl group,
t, t1 and t2 each independently represent an integer from 0 to 300, and t+t1+t2 represents an integer from 20 to 300. )

Furthermore, aliphatic urethane acrylate and polyurethane diacrylate oligomer are particularly preferred.

The content of the polymerizable compound selected from the first component, a polyfunctional (meth)acrylate oligomer having a weight average molecular weight of 1500 or more, is 100% by mass of the total amount of polymerizable compounds contained in the liquid crystal composition of this embodiment. %, from the viewpoint of improving adhesion and scattering properties, it is preferably 0.5% by mass or more, more preferably 1% by mass or more, and particularly preferably 3% by mass or more. Further, from the viewpoint of transparency of the element, the content is preferably 80% by mass or less, more preferably 60% by mass or less, and particularly preferably 50% by mass or less.

[Second component]
The second component is a cyclic monofunctional polymerizable compound represented by the following general formula (ii).

(In the formula, P ⁱⁱ represents a polymerizable functional group,
Z ⁱⁱ represents a single bond or an alkylene group having 1 to 7 carbon atoms, and one or more non-adjacent -CH ₂ - groups in the alkylene group are each independently bonded so that oxygen atoms are not directly adjacent to each other. May be substituted with -O-, -CO-, -COO- or -OCO-,
A ⁱⁱ represents general formulas (ii-9) to (ii-20).

(wherein, one or more -CH ₂ - is each independently substituted with -O-, -S-, -COO-, -OCO-, -NH-, -NCH ₃ -, or -CO-) However, when there are two or more oxygen atoms and/or sulfur atoms in total in general formulas (ii-9) to (ii-20), these may be -O-O-, -O- They do not bond to each other like S- or -SS-, and one or more -CH ₂ -CH ₂ - may be substituted with a -CH=CH- group, and The hydrogen atoms in general formulas (ii-9) to (ii-20) may be substituted with an alkyl group having 1 to 8 carbon atoms, and the alkyl group may be linear or branched. One or more non-adjacent -CH ₂ - in the alkyl group may be independently replaced with -O-, -CO-, -COO- or -OCO- so that oxygen atoms are not directly adjacent to each other. It may be substituted. Also, the black dot in the formula represents the bond to Z ⁱⁱ .))

In the above formulas (ii-9) to (ii-20), the above formulas (ii-9), (ii-10), (ii-11), (ii-15), (ii-16), (ii- 17) and (ii-19) are preferred.

The second component, the compound represented by general formula (ii), is a material with excellent flexibility, and when this compound is used, it is possible to maintain cloudiness even in a bent state. Moreover, it is possible to improve the adhesion and the compatibility of each component in the polymerizable composition. The compound represented by general formula (ii) is a non-liquid crystal compound.

In the compound represented by the general formula (ii), P ⁱⁱ represents a polymerizable functional group, and preferably each of the following formulas (P-1) to (P-20) independently represents a polymerizable functional group. More preferred. Furthermore, in the following formulas (P-1) to (P-20), * represents a bond with a carbon atom or another atom.

Among the polymerizable groups represented by formulas (P-1) to (P-20) above, formula (P-1), formula (P-2), formula (P-2), and -7), formula (P-12), or formula (P-13) is preferred, formula (P-1), formula (P-2), or formula (P-7) is more preferred, and especially formula (P- 1) and formula (P-2) are preferred.

In the compound represented by general formula (ii), Z ⁱⁱ represents a single bond or an alkylene group having 1 to 9 carbon atoms, and one or more -CH ₂ - in the alkylene group is One or more hydrogen atoms present in the alkylene group may be independently substituted with -O-, -CO-, -COO- or -OCO- so that the oxygen atoms are not directly adjacent to each other. Each atom may be independently substituted with a fluorine atom, but is preferably a single bond or an alkylene group having 1 to 6 carbon atoms, and is preferably a single bond or an alkylene group having 1 to 3 carbon atoms. More preferably, a single bond or a -CH ₂ - group is even more preferred.

In the compound represented by the general formula (ii), A ⁱⁱ in the formula preferably has a heterocyclic structure having an oxygen atom and a sulfur atom in A ⁱⁱ from the viewpoint of further improving the adhesion. The following general formulas (ii-a6) to (ii-a11) are preferred.

(In the formula, one or more -CH ₂ - may be each independently substituted with -CO-, and hydrogen atoms in general formulas (ii-a6) to (ii-a11) are carbon atoms. It may be substituted with 1 to 8 alkyl groups, and one or more non-adjacent --CH ₂ -- in the alkyl group are each independently substituted with --O-, so that oxygen atoms are not directly adjacent to each other. It may be substituted with -CO-, -COO- or -OCO-.Also, the black dot in the formula represents the bond to Z ⁱⁱ .) Specifically, from the following (II-35) to ( Compound II-51) is preferred.

(In the formula, X ⁵ represents a hydrogen atom or a methyl group.) Among structural formulas (II-35) to (II-51), (II-36) to (II-51) are preferable, and (II-36 ), (II-38), (II-39), (II-40), (II-45), and (II-47) are more preferred.

When using the compound represented by general formula (ii) as the second component, the content is determined based on 100% by mass of the total amount of the polymerizable compound contained in the liquid crystal composition of this embodiment, adhesion, From the viewpoint of improving scattering properties, the content is preferably 0.5% by mass or more, more preferably 1% by mass or more, and particularly preferably 3% by mass or more. Further, from the viewpoint of transparency of the element, the content is preferably 80% by mass or less, more preferably 60% by mass or less, and particularly preferably 50% by mass or less.

[Third component]
The third component is a mesogenic polymerizable compound represented by the following general formula (P).

(In the above general formula (P), R ^p1 represents a hydrogen atom, a fluorine atom, a cyano group, an alkyl group having 1 to 15 carbon atoms, or -Sp ^p2 -P ^p2 , and R p1 represents one or none of the alkyl groups. Two or more adjacent -CH ₂ - may each be independently substituted with -CH=CH-, -C≡C-, -O-, -CO-, -COO- or -OCO-, One or more hydrogen atoms in the alkyl group may be each independently substituted with a cyano group, a fluorine atom or a chlorine atom,
P ^p1 and P ^p2 each independently represent the general formula (P ^p1 -1) to formula (P ^p1 -9)

(In the formula, R ^p11 and R ^p12 each independently represent a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms, W ^p11 is a single bond, -O -, -COO- or a methylene group, and t ^p11 represents 0, 1 or 2, but if multiple R ^p11 , R ^p12 , W ^p11 and/or t ^p11 exist in the molecule, they are the same. It may be different or different.)
represents one of

Sp ^p1 and Sp ^p2 each independently represent a single bond or a spacer group,
Z ^p1 and Z ^p2 each independently represent a single bond, -O-, -S-, -CH ₂ -, -OCH ₂ -, -CH ₂ O-, -CO-, -C ₂ H ₄ -, - COO-, -OCO-, -OCOOCH ₂ -, -CH ₂ OCOO-, -OCH ₂ CH ₂ O-, -CO-NR ^ZP1 -, -NR ^ZP1 -CO-, -SCH ₂ -, -CH ₂ S- , -CH=CR ^ZP1 -COO-, -CH=CR ^ZP1 -OCO-, -COO-CR ^ZP1 =CH-, -OCO-CR ^ZP1 =CH-, -COO-CR ^ZP1 =CH-COO-, -COO -CR ^ZP1 =CH-OCO-, -OCO-CR ^ZP1 =CH-COO-, -OCO-CR ^ZP1 =CH-OCO-, -(CH ₂ ) _z -COO-, -(CH ₂ ) ₂ -OCO- , -OCO-(CH ₂ ) ₂ -, -(C=O)-O-(CH ₂ ) ₂ -, -CH=CH-, -CF=CF-, -CF=CH-, -CH=CF- , -CF ₂ -, -CF ₂ O-, -OCF ₂ -, -CF ₂ CH ₂ -, -CH ₂ CF ₂ -, -CF ₂ CF ₂ - or -C≡C- (wherein R ^ZP1 is Each independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, but if multiple R ^ZP1s exist in the molecule, they may be the same or different.)
represents,

A ^p1 , A ^p2 and A ^p3 are each independently,
(a ^p ) 1,4-cyclohexylene group (one -CH ₂ - or two or more non-adjacent -CH ₂ -s present in this group may be replaced with -O-)
(b ^p ) 1,4-phenylene group (one -CH= or two or more non-adjacent -CH= present in this group may be replaced with -N=) and (c ^p ) Naphthalene-2,6-diyl group, 1,2,3,4-tetrahydronaphthalene-2,6-diyl group, decahydronaphthalene-2,6-diyl group, phenanthrene-2,7-diyl group or anthracene -2,6-diyl group (one -CH= or two or more non-adjacent -CH= present in these groups may be replaced with -N=)
represents a group selected from the group consisting of, and one or more hydrogen atoms present in the above group (a ^p ), group (b ^p ), and group (c ^p ) are each independently a halogen atom. , a cyano group, an alkyl group having 1 to 8 carbon atoms, or -Sp ^p2 -P ^p2 , and one or more non-adjacent -CH ₂ - in the alkyl group are each independently may be substituted with -CH=CH-, -C≡C-, -O-, -CO-, -COO- or -OCO-,
m ^p1 represents 0, 1, 2 or 3, and when there are multiple Z ^p1 , A ^p2 , Sp ^p2 and/or P ^p2 in the molecule, they may be the same or different; A ^p3 represents a single bond when m ^p1 is 0 and A ^p1 is a phenanthrene-2,7-diyl group or anthracene-2,6-diyl group. )

Compounds represented by are preferred. Moreover, it is preferable to contain one or more types of polymerizable monomers.

In the general formula (P) according to the present invention, R ^p1 is preferably -Sp ^p2 -P ^p2 .
P ^p1 and P ^p2 are each independently preferably one of formulas (P ^p1 -1) to (P ^p1 -3), and preferably (P ^p1 -1).
It is preferable that R ^p11 and R ^p12 are each independently a hydrogen atom or a methyl group.
t ^p11 is preferably 0 or 1.
W ^p11 is preferably a single bond, a methylene group, or an ethylene group.
m ^p1 is preferably 0, 1 or 2, preferably 0 or 1.

Z ^p1 and Z ^p2 each independently represent a single bond, -OCH ₂ -, -CH ₂ O-, -CO-, -C ₂ H ₄ -, -COO-, -OCO-, -COOC ₂ H ₄ - , -OCOC ₂ H ₄ -, -C ₂ H ₄ OCO-, -C ₂ H ₄ COO-, -CH=CH-, -CF ₂ -, -CF ₂ O-, -(CH ₂ ) ₂ -COO- , -(CH ₂ ) ₂ -OCO-, -OCO-(CH ₂ ) ₂ -, -CH=CH-COO-, -COO-CH=CH-, -OCOCH=CH-, -COO-(CH ₂ ) ₂ -, -OCF ₂ - or -C≡C- is preferable, and a single bond, -OCH ₂ -, -CH ₂ O-, -C ₂ H ₄ -, -COO-, -OCO-, -COOC ₂ H ₄ -, -OCOC ₂ H ₄ -, -C ₂ H ₄ OCO-, -C ₂ H ₄ COO-, -CH=CH-, -(CH ₂ ) ₂ -COO-, -(CH ₂ ) ₂ -OCO- , -OCO-(CH ₂ ) ₂ -, -CH=CH-COO-, -COO-CH=CH-, -OCOCH=CH-, -COO-(CH ₂ ) ₂ - or -C≡C- are preferred .
From the viewpoint of solubility, Z ^p1 and Z ^p2 are preferably other than a single bond, but from the viewpoint of polymer morphology and degree of crosslinking, a single bond is preferable, and it is particularly preferable to adjust the bond as appropriate from the balance of both. .

Sp ^p1 and Sp ^p2 each independently represent a single bond or a spacer group, and the spacer group is preferably an alkylene group having 1 to 30 carbon atoms, and -CH ₂ - in the alkylene group is such that oxygen atoms are connected to each other. Unless directly linked, it may be substituted with -O-, -CO-, -COO-, -OCO-, -CH═CH- or -C≡C-, and the hydrogen atom in the alkylene group is a halogen atom. Although it may be substituted with, a straight chain alkylene group having 1 to 10 carbon atoms or a single bond is preferable. From the viewpoint of solubility, Sp ^p1 and Sp ^p2 are preferably other than single bonds, but from the viewpoint of polymer morphology and degree of crosslinking, single bonds are preferable, and it is particularly preferable to adjust the balance between the two as appropriate.

A ^p1 , A ^p2 and A ^p3 are each independently preferably a 1,4-phenylene group or a 1,4-cyclohexylene group, and preferably a 1,4-phenylene group. The 1,4-phenylene group is preferably substituted with one fluorine atom, one methyl group, or one methoxy group in order to improve compatibility with the liquid crystal compound.

When using the mesogenic polymerizable compound represented by the general formula (P) as the third component, the content is preferably 0.5% by mass or more from the viewpoint of improving adhesion and scattering properties, It is more preferably 1% by mass or more, particularly preferably 3% by mass or more. Further, from the viewpoint of transparency of the element, the content is preferably 80% by mass or less, more preferably 60% by mass or less, and particularly preferably 50% by mass or less.

Specific examples of the polymerizable compound represented by the above general formula (P) include those having the following structure.

[Fourth component]
The fourth component is a polyfunctional polymerizable oligomer or a polyfunctional polymerizable monomer having a weight average molecular weight of less than 1500 and is represented by the following general formula (iv). Further, the weight average molecular weight is preferably 1000 or less, more preferably 800 or less.

(In the formula, Y ³¹ represents a hydrogen atom or a methyl group,
X ³¹ represents an alkylene group having 130 or less carbon atoms, and the alkylene group may have a cyclic hydrocarbon group or a branched chain, and one or more of the alkylene group or the cyclic hydrocarbon group -CH ₂ - groups are each independently -O-, -NH-, -CO-, -COO-, -OCO-, -CH=CH-, or -C≡ so that oxygen atoms are not directly adjacent to each other. It may be substituted with C-, and one or more hydrogen atoms present in the alkylene group or cyclic hydrocarbon group may be each independently substituted with a fluorine atom or -OH. ,
n ³¹ represents an integer from 2 to 6. )
Further, X ³¹ is preferably an alkylene group having 100 or less carbon atoms.

For the polyfunctional polymerizable oligomer or polyfunctional polymerizable monomer with a weight average molecular weight of less than 1500 represented by the general formula (iv), it is preferable to use a polymerizable compound represented by the general formula (iv-b1). preferable.

(In the formula, Y ¹ and Y ² represent a hydrogen atom or a methyl group,
X ¹ represents a straight chain or branched alkylene having 2 to 80 carbon atoms, and any carbon atom of the alkylene is replaced by -O-, -CO-, -COO-, It may be substituted with -OCO-, -CH=CH-, -C≡C- or OH. )
Here, in the general formula (iv-b1), X ¹ is a linear or branched alkylene having a carbon atom number of 2 to 70, preferably a carbon atom number of 6 to 70. Among them, a range of 8 to 60 is preferable, and a range of 9 to 50 is particularly preferable from the viewpoint of reducing driving voltage.

Examples of the polymerizable compound represented by the above general formula (iv-b1) include those having the following structure.

(In the formula, n and m are values such that n + m is 1 to 10, n ² is 1 to 18, n ³ and m ² are values such that n ³ + m ² is 1 to 18, n ⁴ is 1 to 23, and n ⁵ is 1 ~23, n ⁶ represents 4 to 30, n ⁷ represents 2 to 10, n ⁸ and n ⁹ represent 2 to 10, respectively.)

When using the polymerizable compound represented by the general formula (iv) as the fourth component, the content is preferably 0.5% by mass or more, and 1% by mass from the viewpoint of improving adhesion and scattering properties. % or more, and particularly preferably 3% by mass or more. Further, from the viewpoint of transparency of the element, the content is preferably 80% by mass or less, more preferably 60% by mass or less, and particularly preferably 50% by mass or less.

[Fifth component]
The fifth component is a chain monofunctional polymerizable compound represented by the following general formula (vi).

(In the formula, P ^vi1 represents a polymerizable group,
R ^vi2 represents a linear or branched alkyl group having 1 to 22 carbon atoms, and one or more -CH ₂ - groups in the alkyl group are each independent so that oxygen atoms are not directly adjacent to each other. may be substituted with -O-, -CO-, -COO-, -OCO- or -P(=O)(-OH)-, and one or more hydrogen atoms present in the alkyl group Each atom may be independently substituted with a fluorine atom or -OH. )

In the compound represented by general formula (vi), P ^vi1 represents a polymerizable functional group, and is preferably the same as the polymerizable group represented by P ⁱⁱ in general formula (ii).
In the compound represented by the general formula (vi), R ^vi2 in the formula preferably represents a straight chain or branched alkyl group having 3 to 20 carbon atoms; It is particularly preferable to represent an alkyl group from the viewpoint of suppressing crystallinity, even more preferably to represent a branched alkyl group, and even more preferably to represent a branched alkyl group having 9 to 24 carbon atoms.

When R ^vi2 represents a linear alkyl group, examples of the compound represented by general formula (v) include ethyl (meth)acrylate, 2-hydroxyethyl acrylate, propyl (meth)acrylate, butyl (meth)acrylate, Pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, lauryl (meth)acrylate, tridecyl (meth)acrylate, tetradecyl ( Mono(meth)acrylates having a linear alkyl chain such as meth)acrylate, hexadecyl(meth)acrylate, stearyl(meth)acrylate, docosyl(meth)acrylate, or a linear alkyl chain represented by the structure below. Mono(meth)acrylates having the following are preferred.
Further, as the compound represented by the general formula (vi), an acrylate in which R ^vi1 in the general formula (vi) has a linear ether chain structure is preferable. The acrylate having the ether chain structure is preferably a compound represented by the following structure.

(In the above general formulas (vi-a1) to (vi-a3), q represents an integer of 1 to 12, preferably 1 to 5, more preferably 1 to 3.)
Among the above general formula (vi), it is preferable to use a mono(meth)acrylate having a linear alkyl chain from the viewpoint of achieving a remarkable effect of reducing the driving voltage.
When R ^vi2 represents a branched alkyl group, the compound represented by general formula (vi) is preferably a mono(meth)acrylate having a branched alkyl chain represented by the following structure. Further, as the compound represented by the general formula (vi), isobutyl (meth)acrylate, isononyl (meth)acrylate, isodecyl (meth)acrylate, isomyristyl (meth)acrylate, and isostearyl (meth)acrylate are preferable.

Further, as the compound represented by the general formula (vi), an acrylate in which R ^vi1 in the general formula (vi) has a linear ether chain structure is preferable. The acrylate having the ether chain structure is preferably a compound represented by the following structure.

(In the formula, q represents an integer of 1 to 10, preferably 1 to 5, more preferably 1 to 3)
Among these, it is particularly preferable to use mono(meth)acrylates having a branched alkyl chain because they have a remarkable effect of reducing the driving voltage while maintaining good transparency when no voltage is applied.

When using the chain monofunctional polymerizable compound represented by the general formula (vi) as the fifth component, the content is preferably 0.5% by mass or more from the viewpoint of improving adhesion and scattering properties. , more preferably 1% by mass or more, particularly preferably 3% by mass or more. Further, from the viewpoint of transparency of the element, the content is preferably 80% by mass or less, more preferably 60% by mass or less, and particularly preferably 50% by mass or less.

[Polymerization initiator]
The liquid crystal composition of this embodiment can contain a polymerization initiator when it contains a polymerizable compound (MA). The polymerization initiator used in this embodiment is used to polymerize the liquid crystal composition of this embodiment. The photopolymerization initiator used when polymerization is carried out by light irradiation is not particularly limited, but it has the above-mentioned one polymerizable group, the polymerizable compound (MA) of this embodiment, and a mesogenic skeleton. Known and commonly used materials can be used as long as they do not inhibit the orientation state of the polymerizable compound (MA).

For example, 1-hydroxycyclohexyl phenyl ketone "Omnirad 184", 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropan-1-one "Omnirad 1173", 2-methyl-1-[(methylthio)phenyl]- 2-morpholinopropane-1 “Omnirad 907”, 2,2-dimethoxy-1,2-diphenylethan-1-one “Omnirad BDK”, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl )-butanone "Omnirad 369"), 2-dimethylamino-2-(4-methylbenzyl)-1-(4-morpholino-phenyl)butan-1-one "Omnirad 379", 2,2-dimethoxy-2- Phenylacetophenone "Omnirad 651", 2,2-dimethoxy-1,2-diphenylethan-1-one, bis(2,4,6-trimethylbenzoyl)-diphenylphosphine oxide "Omnirad TPO", 2,4,6 -Trimethylbenzoyl-phenyl-phosphine oxide "Omnirad 819" (manufactured by IGM Resins Co., Ltd.), 1,2-octanedione, 1-[4-(phenylthio)-,2-(O-benzoyloxime)], ethanone " Irgacure OXE01”), 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-,1-(O-acetyloxime) “Irgacure OXE02”, “Irgacure OXE04” (BASF (manufactured by ADEKA Co., Ltd.), "ADEKA ARCLES NCI-831", "ADEKA ARCLES NCI-930", "ADEKA ARCLES N-1919" (manufactured by ADEKA Corporation), 2,4-diethylthioxanthone (manufactured by Nippon Kayaku Co., Ltd.) A mixture of isopropylthioxanthone (Kayacure ITX, manufactured by Ward Prekinsop) and ethyl p-dimethylaminobenzoate (Kayacure EPA, manufactured by Nippon Kayaku Co., Ltd.) and ethyl p-dimethylaminobenzoate (Kayacure DETX) A mixture of "esacure ONE", "esacure KIP150", "esacure KIP160", "esacure 1001M", "esacure A198", "esacure KIP IT", "esacure KTO46", "esacure TZT" (manufactured by Lamberti Corporation), Examples include "Speed Cure BMS", "Speed Cure PBZ", and "Benzophenone" (manufactured by LAMBSON). Furthermore, a photoacid generator can be used as a photocationic initiator. Examples of the photoacid generator include diazodisulfone compounds, triphenylsulfonium compounds, phenylsulfone compounds, sulfonylpyridine compounds, triazine compounds, and diphenyliodonium compounds.

The content of the photopolymerization initiator is preferably 0.05 to 10% by mass, particularly preferably 0.1 to 3% by mass, based on 100% by mass of the total amount of the liquid crystal composition of the present embodiment. These can be used alone or in combination of two or more.

Further, as the thermal polymerization initiator used in thermal polymerization, known and commonly used ones can be used, such as methyl acetoacetate peroxide, cumene hydroperoxide, benzoyl peroxide, bis(4-t-butylcyclohexyl). Peroxydicarbonate, t-butylperoxybenzoate, methyl ethyl ketone peroxide, 1,1-bis(t-hexylperoxy)3,3,5-trimethylcyclohexane, p-pentahydroperoxide, t-butylhydro Organic peroxides such as peroxide, dicumyl peroxide, isobutyl peroxide, di(3-methyl-3-methoxybutyl) peroxydicarbonate, 1,1-bis(t-butylperoxy)cyclohexane, 2, Azonitrile compounds such as 2'-azobisisobutyronitrile, 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(2-methyl-N-phenylpropion-amidine) dihydro Azoamidine compounds such as chloride, azoamide compounds such as 2,2-azobis{2-methyl-N-[1,1-bis(hydroxymethyl)-2-hydroxyethyl]propionamide}, 2,2'-azobis(2 , 4,4-trimethylpentane) and the like can be used. The content of the thermal polymerization initiator is preferably 0.1 to 10% by mass, and 1 to 6% by mass, based on 100% by mass of the total amount of polymerizable compounds (MA) used in the polymerizable composition of the liquid crystal composition of the present embodiment. % is particularly preferred. These can be used alone or in combination of two or more.

The liquid crystal composition of the present embodiment contains a polymerization inhibitor, antioxidant, light stabilizer, Chain transfer agents, dyes, dyes, pigments, particles with a particle diameter of less than 1 μm, chiral compounds, or alignment materials can be added.

[Polymerization inhibitor]
The polymerization inhibitor used in this embodiment is used to support the efficacy of the polar polymerizable compound (MA), which is the second component, by controlling the polymerization reaction of the liquid crystal composition of this embodiment. Can be done. As such compounds, known and commonly used compounds can be used.
For example, p-methoxyphenol, cresol, t-butylcatechol, 3.5-di-t-butyl-4-hydroxytoluene, 2.2'-methylenebis(4-methyl-6-t-butylphenol), 2.2 '-Methylenebis(4-ethyl-6-t-butylphenol), 4,4'-thiobis(3-methyl-6-t-butylphenol), 4-methoxy-1-naphthol, 4,4'-dialkoxy-2 , 2'-bi-1-naphthol, etc., hydroquinone, methylhydroquinone, tert-butylhydroquinone, p-benzoquinone, methyl-p-benzoquinone, tert-butyl-p-benzoquinone, 2,5-diphenylbenzoquinone , 2-hydroxy-1,4-naphthoquinone, 1,4-naphthoquinone, 2,3-dichloro-1,4-naphthoquinone, anthraquinone, diphenoquinone, etc. are preferred, and p-methoxyphenol, 4-methoxyphenol, etc. Particularly preferred are 1-naphthol, tert-butylhydroquinone, and 2-hydroxy-1,4-naphthoquinone.
The content of the polymerization inhibitor is preferably 0 to 2.0% by mass, more preferably 0 to 0.5% by mass, based on the liquid crystal composition of this embodiment.

〔Antioxidant〕
The antioxidant used in this embodiment can be used to impart practical durability to the polymer dispersed liquid crystal light control element of this embodiment. As such compounds, hydroquinone derivatives, nitrosamine polymerization inhibitors, hindered phenol antioxidants, and the like can be used.
Specifically, tert-butylhydroquinone, "Q-1300" and "Q-1301" from Wako Pure Chemical Industries, Ltd., pentaerythritol tetrakis [3-(3,5-di-tert-butyl-4-hydroxyphenyl)] Propionate "IRGANOX1010", Thiodiethylenebis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate "IRGANOX1035", Octadecyl-3-(3,5-di-tert-butyl-4-hydroxy phenyl) propionate “IRGANOX1076”, “IRGANOX1135”, “IRGANOX1330”, 4,6-bis(octylthiomethyl)-o-cresol “IRGANOX1520L”, “IRGANOX1726”, “IRGANOX245”, “IRGANOX259” , “IRGANOX3114”, “ IRGANOX3790, IRGANOX5057, IRGANOX565 (manufactured by BASF Corporation), ADEKA STAB AO-20, AO-30, AO-40, AO-50, AO-60, AO-80, Sumitomo Sumilizer BHT, Sumilizer BBM-S, and Sumilizer GA-80 manufactured by Kagaku Co., Ltd., and compounds having structures represented by the following general formulas are preferred.

In general formulas (H-1) to (H-3), R ^H1 is an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, or Represents an alkenyloxy group having 2 to 10 carbon atoms, where one -CH ₂ - or two or more non-adjacent -CH ₂ -s present in the group are each independently -O- or -S- Furthermore, one or more hydrogen atoms present in the group may be each independently substituted with a fluorine atom or a chlorine atom. More specifically, it may be an alkyl group having 2 to 7 carbon atoms, an alkoxy group having 2 to 7 carbon atoms, an alkenyl group having 2 to 7 carbon atoms, or an alkenyloxy group having 2 to 7 carbon atoms. Preferably, an alkyl group having 3 to 7 carbon atoms or an alkenyl group having 2 to 7 carbon atoms is more preferable.

Among them, pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, and Compounds represented by the general formulas (H-2) to (H-3) are particularly preferred.
The content of the antioxidant is preferably 0 to 2.0% by mass, and 0 to 0.5% by mass, based on 100% by mass of the total amount of polymerizable compounds (MA) used in the liquid crystal composition of the present embodiment. It is more preferable that it is mass %.

[Light stabilizer]
The light stabilizer used in this embodiment can be used to impart practical durability to the liquid crystal light control element of this embodiment. Such compounds include, for example, "TINUVIN 111FDL", "TINUVIN 123", "TINUVIN 144", "TINUVIN 152", "TINUVIN 292", "TINUVIN 622", "TINUVIN 770", "TINUVIN 765". ”, “TINUVIN 780", "TINUVIN 905", "TINUVIN 5100", "TINUVIN 5050", "TINUVIN 5060", "TINUVIN 5151", "CHIMASSORB 119FL", "CHIMASSORB 944FL", "CHI MASSORB 944LD” (manufactured by BASF Corporation) , "ADK STAB LA-52", "ADK STAB LA-57", "ADK STAB LA-62", "ADK STAB LA-67", "ADK STAB LA-63P", "ADK STAB LA-68LD", "ADK STAB LA-77", Examples include "ADEKA STAB LA-82" and "ADEKA STAB LA-87" (manufactured by ADEKA Co., Ltd.).
The amount of the ultraviolet absorber added is preferably 0.0 to 2.0% by mass, and 0.0 to 1% by mass, based on the total amount of polymerizable compounds (MA) used in the liquid crystal composition of this embodiment. More preferably, it is .0% by mass.

[Chain transfer agent]
The chain transfer agent used in this embodiment can be used to further improve the adhesion between the liquid crystal composition and the base material. As a chain transfer agent, mercaptan compounds such as octyl mercaptan, n-butyl mercaptan, n-pentyl mercaptan, n-hexadecyl mercaptan, n-tetradecyl mercaptan, n-dodecyl mercaptan, t-tetradecyl mercaptan, t-dodecyl mercaptan, etc. , hexanedithiol, decanedithiol, 1,4-butanediol bisthiopropionate, 1,4-butanediol bisthioglycolate, ethylene glycol bisthioglycolate, ethylene glycol bisthiopropionate, trimethylolpropane tristhio Glycolate, trimethylolpropane tristhiopropionate, trimethylolpropane tris(3-mercaptobutyrate), pentaerythritol tetrakisthioglycolate, pentaerythritol tetrakisthiopropionate, tris(2-hydroxyethyl) trimercaptopropionate Thiol compounds such as isocyanurate, 1,4-dimethylmercaptobenzene, 2,4,6-trimercapto-s-triazine, 2-(N,N-dibutylamino)-4,6-dimercapto-s-triazine, penta Examples include phenylethane, α-methylstyrene dimer, acrolein, allyl alcohol, terpinolene, α-terpinene, γ-terbinene, dipentene, etc.
Specifically, compounds represented by the following general formulas (9-1) to (9-8), α-methylstyrene dimer, and α-terpinene are preferred.

In the formula, R ⁹⁵ represents an alkyl group having 2 to 18 carbon atoms, the alkyl group may be linear or branched, and one or more methylene groups in the alkyl group are oxygen atoms. , and the sulfur atoms may be substituted with an oxygen atom, a sulfur atom, -CO-, -OCO-, -COO-, or -CH=CH-, and R ⁹⁶ is a carbon atom Represents an alkylene group of number 2 to 18, and one or more methylene groups in the alkylene group are oxygen atoms, sulfur atoms, -CO-, -OCO-, assuming that the oxygen atom and sulfur atom are not directly bonded to each other. , -COO-, or -CH=CH-.
The content of the chain transfer agent is preferably 0.01 to 10% by mass with respect to 100% by mass of the total amount of polymerizable compounds (MA) used in the polymerizable composition of the liquid crystal composition of the present embodiment, More preferably, it is 0.01 to 5.0% by mass.

[Method for manufacturing liquid crystal composition]
The liquid crystal composition according to the present embodiment can be manufactured by, for example, mixing the above-mentioned non-polymerizable liquid crystal compound (LB), the dichroic dye, and, if necessary, the above-mentioned other compounds and additives. can.

More specifically, a step of obtaining a liquid crystal composition by mixing the non-polymerizable liquid crystal compound (LB) represented by the above-mentioned general formula (v) and, if necessary, other compounds mentioned above; It can be manufactured through a process of obtaining a dichroic dye-containing liquid crystal composition by mixing the dichroic dye used in the liquid crystal composition and optionally additives.

Moreover, it can be manufactured by a process of obtaining a liquid crystal composition by mixing a non-polymerizable liquid crystal compound (LB), a dichroic dye, and optionally additives in any order.

(Liquid crystal light control element)
The liquid crystal light control element of this embodiment is obtained by sandwiching the liquid crystal composition of this embodiment described above between a pair of substrates. In the liquid crystal light control device of this embodiment, the non-polymerizable liquid crystal compound (LB) is vertically aligned on the substrate in a smectic A phase.
In order to maintain the transparent state and provide stability, it is preferable that the liquid crystal light control element of this embodiment is one in which the surface of the substrate is subjected to vertical alignment treatment.
Since the liquid crystal light control element of this embodiment does not require voltage and can be driven by light energy such as sunlight, the liquid crystal light control element of this embodiment does not need to have a transparent electrode.

〔substrate〕
The substrate used in the liquid crystal light control element of this embodiment is a substrate commonly used for liquid crystal display elements, organic light emitting display elements, other display elements, optical components, liquid crystal light control elements, colorants, markings, printed matter, and optical films. Therefore, in applications where emphasis is placed on heat resistance in the manufacturing process of the liquid crystal light control element and the temperature range in which it is used, or transparency that can withstand practical use, the material may be used. , there are no particular restrictions.
Examples of such substrates include glass substrates, metal substrates, ceramic substrates, plastic substrates, and organic materials such as paper. In particular, when the base material is an organic material, examples thereof include cellulose derivatives, polyolefins, polyesters, polycarbonates, polyacrylates, polyarylates, polyether sulfones, polyimides, polyphenylene sulfides, polyphenylene ethers, nylon, and polystyrene. Among these, it is preferable to use plastic base materials such as polyester, polystyrene, polyolefin, cellulose derivatives, polyarylate, polycarbonate, and polyimide.

Although a flat plate shape is shown as the shape of the substrate, other shapes such as those having a curved surface may be used. Further, the substrate may have an antireflection function or a reflection function as necessary. Due to the nature of the device of this embodiment that utilizes the optical phase transition of a photoisomerizable dye, it is preferable that both substrates be transparent.

In order to improve the adhesion in the liquid crystal light control element of this embodiment, these substrates may be subjected to surface treatment. Examples of the surface treatment include ozone treatment, plasma treatment, corona treatment, and silane coupling treatment. In addition, in order to adjust the transmittance and reflectance of light, an organic thin film, an inorganic oxide thin film, a metal thin film, etc. are provided on the surface of the substrate by a method such as vapor deposition, or a base material is used to add optical value. The material may be a pickup lens, a rod lens, an optical disk, a retardation film, a light diffusion film, a microlens sheet, a color filter, or the like.

[Alignment film layer]
The substrate may be subjected to alignment treatment so that the liquid crystal molecules in the liquid crystal light control element of this embodiment are aligned horizontally or vertically, or may be provided with an alignment film. Examples of the alignment treatment include stretching treatment, rubbing treatment, polarized visible light irradiation treatment, ion beam treatment, and oblique deposition treatment of SiO ₂ on the base material. Such alignment films include polyimide, polysiloxane, polyamide, polyvinyl alcohol, polycarbonate, polystyrene, polyphenylene ether, polyarylate, polyethylene terephthalate, polyether sulfone, epoxy resin, epoxy acrylate resin, acrylic resin, azo compound, coumarin. Compounds such as chalcone compounds, cinnamate compounds, fulgide compounds, anthraquinone compounds, and arylethene compounds, or polymers and copolymers of the above compounds can be mentioned. When rubbing is performed to impart a tilt angle to the liquid crystal molecules, the compound to be aligned by rubbing may be one in which the crystallization of the material is promoted by the alignment or by adding a heating step after the alignment. preferable. Among compounds that perform alignment treatment other than rubbing, it is preferable to use photoalignment materials.
Generally, when a liquid crystal composition is brought into contact with a substrate having an alignment function, liquid crystal molecules are aligned near the substrate along the direction in which the substrate is aligned. Whether the liquid crystal molecules are oriented horizontally, obliquely, or perpendicularly to the substrate is largely influenced by the alignment treatment method for the substrate.

The liquid crystal light control device of this embodiment has a layer containing a liquid crystal composition, preferably a composite layer containing a polymer network and a liquid crystal compound. The polymer network is a polymer network derived from the polymerizable compound (MA) contained in the liquid crystal composition of the present embodiment described above, and the liquid crystal compound is a polymer network derived from the polymerizable compound (MA) contained in the liquid crystal composition of the present embodiment described above. It is a liquid crystal compound (LB).

The liquid crystal light control element of this embodiment is an element that uses the above-described liquid crystal light control element using the liquid crystal composition of this embodiment described above and controls the light transmittance of the liquid crystal light control element. The present liquid crystal light control element may be made of laminated glass in which the liquid crystal light control element is sandwiched between two pieces of glass with an interlayer film such as PVB (polyvinyl butyral), EVA (ethylene vinyl acetate copolymer resin), TPU (polyurethane type), or SGP interposed therebetween.

Next, the present embodiment will be specifically described using examples and comparative examples, but the present embodiment is not limited thereto.

(Synthesis example 1)
[Preparation of host liquid crystal LC-1]
According to the liquid crystal compounds and composition ratios shown in Table 1, the following three types of liquid crystal compounds (i) to (iii) and the chiral agent (iv) were mixed in predetermined amounts at 120°C to obtain host liquid crystal LC-1. . In addition, host liquid crystal LC-2 was obtained from the following three types of liquid crystal compounds (i) to (iii) in the same manner as LC-1.
(i) 4-cyano-4'-n-octylbiphenyl (8CB, 45 mol%),
(ii) 4-cyano-4'-n-heptylbiphenyl (7CB, 30 mol%),
(iii) trans-4'-(4-amylcyclohexyl)biphenyl-4-carbonitrile (5CCB, 15 mol%),
(iv) (S)-2-octyl 4-[4-(hexyloxy)benzoyloxy]benzoate (S811, 10 mol%)

(Synthesis example 2)
[Preparation of host liquid crystal LC-2]
In the same manner as in Synthesis Example 1, host liquid crystal LC-2 was obtained from the three types of liquid crystal compounds (i) to (iii) above according to the liquid crystal compounds and composition ratios shown in Table 1.

(Preparation example 1)
[Preparation of homeotropic alignment cell-1]
The glass substrate was ultrasonically cleaned (30 min) using a neutral detergent (Scat 20X-N, 20 times diluted). It was washed in the following order: tap water washing (15 min), pure water ultrasonic washing (30 min), IPA ultrasonic washing (30 min), and then dried.
Next, an ethanol solution (concentration: 0.25 wt%) of noctadecyltrimethoxysilane (silane coupling agent) was prepared. The washed glass substrate was immersed in this ethanol solution for 1 hour, and then heated at 100° C. for 2 hours. Thereafter, after performing IPA ultrasonic cleaning (30 min) and drying, a glass substrate was bonded with a spacer-containing adhesive to produce Cell-1.

(Preparation example 2)
[Preparation of homeotropic orientation cell-2]
In the production process of Production Example 1, Cell-2 was produced by providing an alignment film on the surface of the glass substrate in contact with the liquid crystal composition instead of immersing the glass substrate in the silane coupling agent solution.

(Preparation example 3)
[Preparation of homeotropic alignment cell-3]
In the production process of Production Example 1, Cell-3 was produced using a glass substrate having a transparent electrode layer and without treatment with an alignment agent or installation of an alignment film.

(Examples 1 to 5)
[Preparation of liquid crystal composition]
According to the ratios shown in Table 2, the following components (I) to (V) were mixed at 100° C. to prepare liquid crystal compositions SWLC-1 to SWLC-5 of Examples 1 to 5, respectively.
(I) Host liquid crystal LC-1 obtained in Synthesis Example 1,
(II) 1-octyl-4-[4-(4-cyano-phenylazo)phenyl]piperazine (azobenzene derivative, CPAB),
(III) 1,5-Bis[(4-butylphenyl)amino]-9,10-anthraquinone (magenta dye, BPAAQ),
(IV) Mitsui Toatsu anthraquinone derivative dye (cyan dye, M-137),
1,4-bis[4-(6-acryloyloxyhexyloxy)benzoyloxy]-2-methylbenzene (liquid crystal monomer, C6A),
(V) Irgacure 651 (photopolymerization initiator)

(Examples 6 to 10)
[Preparation of liquid crystal light control element and confirmation of transparent state]
As shown in FIG. 1, the liquid crystal compositions SWLC-1 to SWLC-5 obtained in Examples 1 to 5 were sealed in the homeotropic alignment cell-1 obtained in Preparation Example 1 at 100°C. 6 to 10 liquid crystal light control elements SW-1 to SW-5 were manufactured, respectively. FIG. 1 is a diagram showing an outline of manufacturing liquid crystal light control elements SW-1 to SW-5. After the temperature was lowered to room temperature, the liquid crystals of Examples 6 to 10 were polymerized by irradiation with ultraviolet light (ultra-high pressure mercury lamp 500 W (USHIO, OPM2-502HQ), 366 nm, 5 mW/cm ² , 30 min). Light control elements SW-1 to SW-5 were obtained.
It was confirmed that the liquid crystal light control elements SW-1 to SW-5 obtained in the above steps were in a transparent state.

[Checking the scattering state (heat + light irradiation, sunlight irradiation)]
Using the liquid crystal light control elements SW-1 to SW-5 prepared in Examples 6 to 10 above, the devices were heated to an optimal temperature of about 30 to 45°C within the driving temperature range, and at the same time, a halogen lamp was used to generate a 0.1 mW /cm ² (405 nm) for 30 minutes to simulate sunlight, and the liquid crystal light control elements SW-1 to SW-5 were in a scattering state.
Furthermore, when a liquid crystal light control element was actually attached to a window and exposed to sunlight, a scattering state similar to the above-mentioned conditions under which sunlight was simulated was obtained.

[Evaluation of dimming characteristics of liquid crystal dimming element]
(Visual evaluation)
The obtained liquid crystal light control element was visually evaluated in the transparent state and in the scattering state, and the transparency-scattering control characteristics were evaluated in the following three stages by visual observation and microscopic observation. The results are shown in Table 5.
A: The difference between the transparent state and the scattering state can be easily recognized.
B: The difference between the transparent state and the scattering state can be recognized.
D: The difference between the transparent state and the scattering state is hardly recognizable.

Here, since the liquid crystal light control element SW-5 uses a plurality of dyes, the color tone was not a specific monochrome but a gray scale. This feature is particularly preferable because it is thought to have a wide range of applications as a light control element. However, regarding the color tone, there is no problem with the performance as an element, and since it is from the viewpoint of design and appearance, there is a possibility of various uses depending on the purpose.

(Haze evaluation)
The obtained liquid crystal light control device was evaluated for haze characteristics in a transparent state and a scattering state, and its transparent-scattering control characteristics were evaluated in the following four stages. For haze characteristic evaluation, NDH-7000 manufactured by Nippon Denshoku Industries Co., Ltd. was used. The results are shown in Table 5.
A: The difference in haze between the transmission state and the scattering state is 15% or more. B: The difference in haze between the transmission state and the scattering state is 3% or more and less than 15%. C: The difference in haze between the transmission state and the scattering state is 0.5% or more and less than 3%. D: Haze difference between transmission state and scattering state is less than 0.5%

(Cycle test)
A repeated cycle test of transparency-scattering control characteristics was conducted on the obtained liquid crystal light control device. As a result, repeatability was confirmed for all of the liquid crystal light control elements SW-1 to SW-5.

(Examples 6A to 10A)
[Preparation of liquid crystal light control element and confirmation of transparent state]
The liquid crystal compositions SWLC-1 to SWLC-5 obtained in Examples 1 to 5 were sealed in the homeotropic alignment cell-2 obtained in Production 2 to produce liquid crystal light control elements of Examples 6A to 10A, respectively. did. A transparent state similar to that of the liquid crystal light control elements SW-1 to SW-5 of Examples 6 to 10 was confirmed.

(Examples 6B to 10B)
[Preparation of liquid crystal light control element and confirmation of transparent state]
The liquid crystal compositions SWLC-1 to SWLC-5 obtained in Examples 1 to 5 were sealed in the homeotropic alignment cell-3 obtained in Production 3 to produce liquid crystal light control elements of Examples 6B to 10B, respectively. did. A transparent state similar to that of the liquid crystal light control elements SW-1 to SW-5 of Examples 6 to 10 was confirmed.

(Consideration 1)
From the results of Examples 6 to 10, Examples 6A to 10A, and Examples 6B to 10B, a cell in which a layer with some kind of alignment effect, such as an alignment agent layer, an alignment film layer, or a transparent electrode layer, was installed on a glass substrate. It has been found that by using this method, a liquid crystal light control element exhibiting a transparent state derived from homeotropic alignment can be obtained.

(Examples 11 to 14)
[Thermal properties of liquid crystal composition in liquid crystal light control element]
Thermal characteristics of the polymer-containing liquid crystal compositions in the liquid crystal light control devices SW-1 to SW-4 prepared in Examples 6 to 9 above were measured before and after the heating light irradiation conditions described above. The results are shown in Table 3.
The phase transition behavior in the transparent state (before sunlight irradiation) is the phase transition behavior in the normal stable state. On the other hand, as the photoisomerization reaction progresses due to light irradiation, the phase transition temperature decreases, so the present embodiment is characterized in that the liquid crystal phase changes under the same environmental temperature, resulting in a scattering state.

In Table 3, the meaning of each symbol is shown below.
SmA: Smectic A phase N*: Chiral nematic phase Iso: Isotropic phase

(Examples 15 to 18)
According to the ratios shown in Table 4, liquid crystal compositions SWLC-6 to SWLC-9 of Examples 15 to 18 were prepared in the same manner as in Example 1, respectively.

(Examples 19-27)
Using the liquid crystal compositions SWLC-6 to SWLC-9 obtained in Examples 15 to 18, liquid crystal light control elements SW-6 to SW-9 of Examples 19 to 27 were created in the same manner as Example 6, respectively. did. The same transparent state as in Example 6 was shown. Table 5 shows the results of various evaluations performed using the obtained device.

(Comparative Examples 1-2)
According to the ratios shown in Table 4, liquid crystal compositions Ref-1 and Ref-2 of Comparative Examples 1 and 2 were prepared in the same manner as in Example 1, respectively.

(Comparative Examples 3-4)
Using the liquid crystal compositions ef-1 to Ref-2 obtained in Comparative Examples 1 to 2, liquid crystal light control elements Ref SW-1 to Ref SW-2 of Comparative Examples 3 to 4 were prepared in the same manner as in Example 6. Created each. The same transparent state as in Example 6 was shown. Table 5 shows the results of various evaluations performed using the obtained device.

(Consideration 2)
In the liquid crystal light control elements used in Examples 19 to 23, the difference between the transmission state and the scattering state was easily recognized, and the haze difference between the transmission state and the scattering state was sufficient. Furthermore, the transmission state and the scattering state of the elements produced in Examples 24 to 27 could also be confirmed, and the operation as a light control element could be confirmed.
On the other hand, in all of the elements prepared in Comparative Examples 3 and 4, the transition from the transparent state to the scattering state was not sufficiently achieved by light irradiation, and it was difficult to recognize the difference, and the transition between the transparent state and the scattering state was difficult. The haze difference was also insufficient.
From the above, it was confirmed that the liquid crystal light control device produced using the liquid crystal composition of the present invention exhibits superior performance compared to the liquid crystal light control device of the comparative example.

Claims (12)

A non-polymerizable liquid crystal compound (LB),
A liquid crystal composition containing a dye having at least one photoisomer group,
A liquid crystal composition, wherein the non-polymerizable liquid crystal compound (LB) exhibits a smectic A phase at room temperature and exhibits a chiral nematic phase at a higher temperature than the smectic A phase. The liquid crystal composition according to claim 1, further comprising at least two types of dichroic dyes having different structures from the dye having a photoisomer group. The liquid crystal composition according to claim 1 or 2, further comprising a chiral compound. The liquid crystal composition according to claim 1 or 2, wherein the upper limit temperature of the smectic A phase is 20°C or more and 50°C or less. The liquid crystal composition according to claim 1 or 2, further comprising a polymerizable compound (MA). The liquid crystal composition according to claim 5, further comprising a photopolymerization initiator. A liquid crystal light control element obtained by sandwiching the liquid crystal composition according to claim 1 or 2 between a pair of substrates. A liquid crystal light control element containing a polymer obtained from the polymerizable compound (MA) in the liquid crystal composition according to claim 5. The liquid crystal light control device according to claim 7, wherein the non-polymerizable liquid crystal compound (LB) is vertically aligned on the substrate in a smectic A phase. 8. The liquid crystal light control device according to claim 7, wherein the surface of the substrate is subjected to vertical alignment treatment. The liquid crystal light control element according to claim 7, wherein the substrate does not have a transparent electrode. The liquid crystal light control device according to claim 8, wherein the polymer forms a polymer network.

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