TWI865445B - Liquid crystal compositions, monomer/liquid crystal mixtures, polymer/liquid crystal composites, liquid crystal elements and chiral compounds - Google Patents

Abstract

The present invention provides a liquid crystal composition, which contains at least one chiral compound represented by formula (K1) as a chiral component (K), and contains at least one achiral compound represented by formula (1-A) or formula (1-B) as a achiral component (T).

Description

Liquid crystal compositions, monomer/liquid crystal mixtures, polymer/liquid crystal composites, liquid crystal elements and chiral compounds

The present invention relates to a liquid crystal composition containing chiral components and non-chiral components, a monomer/liquid crystal mixture, a polymer/liquid crystal composite material, a liquid crystal element and a chiral compound.

As a low-voltage driven technology that can achieve important characteristics required for the practical use of light-scattering liquid crystal display devices, a dimming layer using a chiral nematic liquid crystal composition containing a liquid crystal composition, a chiral compound, and a photopolymerizable monomer is disclosed (Patent Documents 1 to 3). The dimming layer produced by photopolymerizing the photopolymerizable monomer contained in the chiral nematic liquid crystal composition in the presence of a polymerization initiator is used in a low-voltage driven liquid crystal device. Specifically, it is used in a dimming window for blocking and transmitting external light or vision in a liquid crystal device that can block external light or vision and perform electrical operations, especially in windows of buildings or store windows, indoor partitions, roof windows, rear windows, etc. of a car. Similar to the isotropic phase (hereinafter sometimes referred to as "non-liquid crystal isotropic phase") in the nematic liquid crystal material, the Kerr effect [Δn(E)=KλE ² (K: Kerr coefficient (Kerr constant), λ: wavelength)] can be observed in the blue phase, which is a kind of optically isotropic liquid crystal phase. The Kerr effect is a phenomenon in which the electro-birefringence value (the birefringence value excited when an electric field is applied to an isotropic medium) Δn(E) is proportional to the square of the electric field E. In addition, a mode in which an electric field is applied to optically isotropic liquid crystal phases such as the blue phase and the polymer-stabilized blue phase to exhibit electro-birefringence has been disclosed (Patent Documents 4 to 9, Non-Patent Documents 1 to 3). Regarding the blue phase, it has been proposed not only to apply it to display elements of this mode, but also to apply it to tunable filters utilizing electro-birefringence, wavefront control elements, liquid crystal lenses, aberration correction elements, aperture control elements, optical head devices, etc. (Patent Documents 7 to 9). [Prior Art Documents] [Patent Documents]

[Patent Document 1] Japanese Patent Publication No. 5-241119 [Patent Document 2] Japanese Patent Publication No. 5-281525 [Patent Document 3] Japanese Patent Publication No. 5-289064 [Patent Document 4] Japanese Patent Publication No. 2003-327966 [Patent Document 5] International Publication No. 200 5/90520 [Patent Document 6] Japanese Patent Publication No. 2005-336477 [Patent Document 7] International Publication No. 2005/080529 [Patent Document 8] Japanese Patent Publication No. 2005-157109 [Patent Document 9] Japanese Patent Publication No. 2006-127707 [Non-Patent Document]

[Non-patent document 1] "Nature Materials" Vol. 1, p. 64 (2002) [Non-patent document 2] "Advanced Materials (Adv. Mater.)" Vol. 17, p. 96 (2005) [Non-patent document 3] "Journal of the Society for Information Display (Journal of the SID)" Vol. 14, p. 551 (2006) [Non-patent document 4] "Soft Matter" Vol. 10, p. 6582 (2014)

[Problems to be solved by the invention] A liquid crystal composition showing a chiral nematic phase or an optically isotropic phase contains a chiral component and an achiral component. Generally speaking, the greater the helical twisting power (HTP) of a chiral compound, the smaller the amount of chiral compound added to the liquid crystal composition to shorten the helical pitch of the liquid crystal. Therefore, a liquid crystal composition having a target helical pitch can be achieved by adding a small amount of a chiral compound. In addition, in the case of a liquid crystal composition used for optical isotropy, a chiral nematic phase or an optically isotropic phase is expressed by adding a small amount of a chiral compound, and in the case of use as a liquid crystal element, effects such as a reduction in driving voltage and suppression of precipitation of the chiral compound can be expected. The reason is that in the liquid crystal composition, the components that contribute to the characteristics of the liquid crystal element such as the driving voltage and the response speed are non-chiral components. By using a chiral compound with a large HTP, the content of the non-chiral component can be increased. In addition, the compatibility of the liquid crystal composition can be improved by using a chiral compound with good compatibility. When used as a liquid crystal element, it can be driven in a wide temperature range including low temperature. In addition, when making a liquid crystal composition, the time required for dissolution can be greatly shortened, so that efficient manufacturing can be achieved and manufacturing costs can be reduced.

Therefore, the subject of the present invention is to provide a liquid crystal composition and a liquid crystal element, which contain chiral components and non-chiral components with high helical twist power (HTP), good compatibility with other liquid crystal compounds, and good reliability such as light resistance, so that the driving voltage is low, the response is high, and the storage stability is good. In addition, a liquid crystal composition and a liquid crystal element are provided that are stable with respect to external light and have excellent light resistance that can be used externally for a long time. [Means for solving the problem]

The inventors of the present invention have conducted diligent research and found that the above problem can be solved by using the following liquid crystal composition: the liquid crystal composition uses a 9,10-ethanoanthracene-based chiral compound as a chiral component and a fluorine-based liquid crystal compound as an achiral component. The specific details are as follows.

[1] A liquid crystal composition comprising at least one chiral compound represented by formula (K1) as a chiral component (K), and at least one achiral compound represented by formula (1-A) or formula (1-B) as a achiral component (T). [Chemistry 1] (In formula (K1), R ^k1 is independently fluorine, chlorine, -C≡N, an alkyl group having 1 to 10 carbon atoms, or an alkenyl group having 2 to 10 carbon atoms, in which at least one -CH ₂ - in the alkyl group may be substituted by -O-, but two consecutive -CH ₂ - groups may not be substituted by -O-, and in these groups, at least one hydrogen group may be substituted by a halogen; Y ^k1 is independently a single bond, or -(CH ₂ ) _n -, where n is an integer of 1 to 20; nk1 and nk2 are independently an integer of 0 to 4, and Rod ^k1 is a partial structural formula (Rod1), in which R ^k2 is hydrogen, fluorine, chlorine, -C≡N, an alkyl group having 1 to 10 carbon atoms, or an alkenyl group having 2 to 10 carbon atoms, in which at least one -CH ₂ - may be substituted by -O-, but two consecutive -CH ₂ - may not be substituted by -O-; in these groups, at least one hydrogen may be substituted by a halogen; Ring A ^k1 , Ring A ^k2 , and Ring A ^k3 are independently 1,4-cyclohexylene, 1,4-phenylene, 1,4-phenylene in which at least one hydrogen is substituted by fluorine, 1,3-dioxane-2,5-diyl, tetrahydropyran-2,5-diyl, or pyrimidine-2,5-diyl; Z ^k1 , Z ^k2 , and Z ^k3 are independently a single bond, -CH ₂ CH ₂ -, -COO-, -OCO-, -OCH ₂ -, -CH ₂ O-, -CF ₂ O-, -OCF ₂ -, -CH=CH-, -CF ₂ CF ₂ -, -CF=CF-, or -C≡C-; mk1 and mk2 are each independently an integer of 0 or 1; in addition, in the partial structure (X1) and partial structure (X2) shown below, in which 0 to 4 R ^k1 are linked to the ring structure, 0 to 4 hydrogen atoms in the hydrogen atoms forming the ring structure may be replaced by R ^k1 ) [Chemical 2] [Chemistry 3] (In formula (1-A) and formula (1-B), R ¹¹ and R ¹² are independently hydrogen, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, or an alkenyl group having 2 to 10 carbon atoms, in which at least one -CH ₂ - may be substituted by -O-, but two consecutive -CH ₂ - groups may not be substituted by -O-, and in these groups, at least one hydrogen may be substituted by a halogen; Ring A ¹¹ , Ring A ¹² , and Ring A ¹³ are independently 1,4-cyclohexylene, 1,4-phenylene, 1,4-phenylene in which at least one hydrogen is substituted by fluorine, 1,3-dioxane-2,5-diyl, tetrahydropyran-2,5-diyl, or pyrimidine-2,5-diyl; Z ¹¹ , Z ^{Z 12} and Z ¹³ are independently a single bond, -CH ₂ CH ₂ -, -COO-, -OCO-, -CH ₂ O-, -OCH ₂ -, -CF ₂ O-, -OCF ₂ -, -CH=CH-, -CF=CF-, or -C≡C-; X ¹¹ is fluorine, chlorine, -SF ₅ , -CHF ₂ , -CF ₃ , -CF ₂ CH ₂ F, -CF ₂ CHF ₂ , -CF ₂ CF ₃ , -(CF ₂ ) ₃ -F, -CF ₂ CHFCF ₃ , -CHFCF ₂ CF ₃ , -(CF ₂ ) ₄ -F, -(CF ₂ ) ₅ -F, -OCHF ₂ , -OCF ₃ , -OCF ₂ CH ₂ F, -OCF ₂ CHF ₂ , -OCH _{2 CF3 , -OCF2CF3} , _-O- ( _CF2 ) _{3 - F} , -OCF2CHFCF3, -OCHFCF2CF3, -O-( _CF2 ) _4- F, -O-( _CF2 ) ₅ -F, -CH= _CF2 , -CH= _CHCF3 , or -CH= _CHCF2CF3 ; ^L11 and ^L12 are _{independently} hydrogen or _fluorine ; ^L13 and ^L14 are independently hydrogen, fluorine, chlorine, or -C≡N, but ^L13 and ^L14 are not both hydrogen; ^S11 is hydrogen or methyl; m and n are independently 0 or 1)

[2] The liquid crystal composition according to [1], wherein the chiral compound represented by formula (K1) is a chiral compound represented by formula (K1-1). (In formula (K1-1), R ^k1 is independently fluorine, chlorine, -C≡N, an alkyl group having 1 to 10 carbon atoms, or an alkenyl group having 2 to 10 carbon atoms, in which at least one -CH ₂ - may be substituted by -O-, but two consecutive -CH ₂ - may not be substituted by -O-, and in these groups, at least one hydrogen may be substituted by a halogen; nk1 and nk2 are independently integers of 0 to 4, Rod ^k1 is the partial structural formula (Rod1-1) or the partial structural formula (Rod1-2), in the partial structural formula (Rod1-1) and the partial structural formula (Rod1-2), R ^k2 is hydrogen, fluorine, chlorine, -C≡N, an alkyl group having 1 to 10 carbon atoms, or an alkenyl group having 2 to 10 carbon atoms, in which at least one -CH 2 - in the alkyl group may be substituted by -O-, but two consecutive -CH _{2 -} may not be substituted by -O-, and in these groups, at least one hydrogen may be substituted by a halogen; - may be substituted by -O-, but two consecutive -CH ₂ - may not be substituted by -O-; in these groups, at least one hydrogen may be substituted by a halogen; Ring A ^k1 , Ring A ^k2 , and Ring A ^k3 are independently 1,4-cyclohexylene, 1,4-phenylene, 1,4-phenylene in which at least one hydrogen is substituted by fluorine, 1,3-dioxane-2,5-diyl, tetrahydropyran-2,5-diyl, or pyrimidine-2,5-diyl; Z ^k2 and Z ^k3 are independently a single bond, -CH ₂ CH ₂ -, -COO-, -OCO-, -OCH ₂ -, -CH ₂ O-, -CF ₂ O-, -OCF ₂ -, -CH=CH-, -CF ₂ CF ₂ -, -CF=CF-, or -C≡C-; mk1 and mk2 are each independently an integer of 0 or 1; in addition, in the partial structure (X1) and the partial structure (X2) shown below in which R ^k1 is linked to the ring structure, 0 to 4 hydrogen atoms in the hydrogen atoms forming the ring structure may be replaced by R ^k1 ) [Chemical 5]

[3] The liquid crystal composition described in [2], wherein in formula (K1-1), R ^k1 is independently an alkyl group having 1 to 10 carbon atoms or an alkenyl group having 2 to 10 carbon atoms, in the alkyl group, at least one -CH ₂ - may be substituted by -O-, but two consecutive -CH ₂ - groups may not be substituted by -O-, and in these groups, at least one hydrogen may be substituted by a halogen; nk1 and nk2 are independently integers of 0 to 4, and Rod ^k1 is any one of the partial structural formulas (Rod1-1A) to (Rod1-1H) and partial structural formulas (Rod1-2A) to (Rod1-2H) shown below. [Chemistry 6] [Chemistry 7] (In the partial structural formulas (Rod1-1A) to (Rod1-1H) and the partial structural formulas (Rod1-2A) to (Rod1-2H), R ^k2 is hydrogen, an alkyl group having 1 to 10 carbon atoms, or an alkenyl group having 2 to 10 carbon atoms, at least one -CH ₂ - in the alkyl group may be substituted by -O-, but two consecutive -CH ₂ - groups may not be substituted by -O-, and at least one hydrogen in these groups may be substituted by a halogen; in addition, the partial structure (X3) shown below in which (F) is linked to a 1,4-phenylene group represents a 1,4-phenylene group in which one or two hydrogens may be substituted by fluorine) [Chemistry 8]

[4] The liquid crystal composition according to any one of [1] to [3], wherein the achiral compound represented by formula (1-A) is any one of the achiral compounds represented by formula (1-A-01) to formula (1-A-22). [Chemistry 10] [Chemistry 11] In formula (1-A-01) to formula (1-A-22), R ¹¹ is independently an alkyl group having 1 to 10 carbon atoms or an alkenyl group having 2 to 10 carbon atoms, at least one -CH ₂ - in the alkyl group and the alkenyl group may be substituted by -O-, but two consecutive -CH ₂ - groups may not be substituted by -O-; Ring A ¹¹ and Ring A ¹² are independently 1,4-cyclohexylene, tetrahydropyran-2,5-diyl, or pyrimidine-2,5-diyl; X ¹¹ is independently fluorine, chlorine, -CF ₃ , or -OCF ₃ ; (F) is hydrogen or fluorine.

[5] The liquid crystal composition according to any one of [1] to [3], wherein the achiral compound represented by formula (1-B) is any one of the achiral compounds represented by formula (1-B-01) to formula (1-B-22). [Chemistry 13] In formula (1-B-01) to formula (1-B-22), R ¹¹ and R ¹² are independently alkyl having 1 to 10 carbon atoms or alkenyl having 2 to 10 carbon atoms, at least one -CH ₂ - in the alkyl and alkenyl groups may be substituted by -O-, but two consecutive -CH ₂ - groups may not be substituted by -O-; Ring A ¹¹ and Ring A ¹² are independently 1,4-cyclohexylene, tetrahydropyran-2,5-diyl, or pyrimidine-2,5-diyl; (F) is hydrogen or fluorine.

[6] The liquid crystal composition according to any one of [1] to [5], wherein the content of the chiral component (K) in the liquid crystal composition is 0.1 wt % to 30 wt %.

[7] The liquid crystal composition according to any one of [1] to [6], wherein the content of the compound represented by formula (1-A) or (1-B) in the achiral component (T) is 50 wt % to 100 wt %.

[8] The liquid crystal composition according to any one of [1] to [6], wherein the content of the compound represented by formula (1-A) in the achiral component (T) is 50 wt % to 100 wt %, and the composition exhibits an optically isotropic liquid crystal phase.

[9] The liquid crystal composition according to any one of [1] to [8], wherein the chiral component (K) further contains at least one chiral compound represented by formula (K2) to formula (K8). (In formula (K2) to formula (K8), R ^K is independently hydrogen, halogen, -C≡N, -N=C=O, -N=C=S or an alkyl group with 1 to 20 carbon atoms, at least one -CH ₂ - in the alkyl group may be substituted by -O-, -S-, -COO-, -OCO-, -CH=CH-, -CF=CF- or -C≡C-, at least one hydrogen in the alkyl group may be substituted by a halogen; A ^K is independently an aromatic 6- to 8-membered ring, a non-aromatic 3- to 8-membered ring, or a condensed ring with 9 to 20 carbon atoms, at least one hydrogen in the ring may be substituted by a halogen, an alkyl group with 1 to 3 carbon atoms or a halogenated alkyl group, the -CH ₂ - may be substituted by -O-, -S- or -NH-, -CH= may be substituted by -N=; Y ^K are independently hydrogen, halogen, alkyl with 1 to 3 carbon atoms, halogenated alkyl with 1 to 3 carbon atoms, aromatic 6- to 8-membered ring, non-aromatic 3- to 8-membered ring, or condensed ring with 9 to 20 carbon atoms, at least one hydrogen of these rings may be substituted by halogen, alkyl with 1 to 3 carbon atoms or halogenated alkyl, -CH ₂ - may be substituted by -O-, -S- or -NH-, -CH= may be substituted by -N=; Z ^K are independently single bond, or alkylene with 1 to 8 carbon atoms, but at least one -CH ₂ - may be substituted by -O-, -S-, -COO-, -OCO-, -CSO-, -OCS-, -N=N-, -CH=N-, -N=CH-, -CH=CH-, -CF=CF- or -C≡C-, and at least one hydrogen may be substituted by a halogen; X ^K each independently represents a single bond, -COO-, -OCO-, -CH ₂ O-, -OCH ₂ -, -CF ₂ O-, -OCF ₂ - or -CH ₂ CH ₂ -; mK each independently represents an integer of 1 to 4)

[10] A monomer/liquid crystal mixture comprising the liquid crystal composition as described in any one of [1] to [9] and a polymerizable monomer.

[11] The monomer/liquid crystal mixture as described in [10], which exhibits a chiral nematic phase in a temperature range of at least 1°C from -20°C to 70°C, and the helical pitch is less than 700 nm in at least a part of the temperature range.

[12] The monomer/liquid crystal mixture as described in [10], wherein the liquid crystal composition is a liquid crystal composition having an optically isotropic liquid crystal phase.

[13] The monomer/liquid crystal mixture according to any one of [10] to [12], wherein the content of the polymerizable monomer is in the range of 0.1 wt % to 50 wt % relative to the total amount of the monomer/liquid crystal mixture.

[14] A polymer/liquid crystal composite material obtained by polymerizing the monomer/liquid crystal mixture as described in [10] in a non-liquid crystal isotropic phase or an optically isotropic liquid crystal phase, and used for a liquid crystal element driven by an optically isotropic liquid crystal phase.

[15] A polymer/liquid crystal composite material obtained by polymerizing the monomer/liquid crystal mixture as described in [10] and used in a light scattering liquid crystal element driven by a chiral nematic phase.

[16] A liquid crystal element, comprising: a pair of substrates having electrodes; a dimming layer sandwiched between the pair of substrates; and an electric field applying component for applying an electric field to the dimming layer via the electrodes, At least one of the pair of substrates is transparent, and the dimming layer comprises the polymer/liquid crystal composite material as described in [14] or [15].

[17] The liquid crystal element as described in [16], wherein the polymer/liquid crystal composite material exhibits a chiral nematic phase and constitutes a light scattering type liquid crystal element.

[18] The liquid crystal element as described in [16] or [17], wherein the content of the polymer in the polymer/liquid crystal composite material is in the range of 0.1 wt % to 50 wt %.

[19] A chiral compound represented by the following formula (K101), formula (K102), or formula (K103).

In this specification, "liquid crystal compound" is a general term for compounds having a liquid crystal phase such as a nematic phase or a smectic phase, and compounds that do not have a liquid crystal phase but can be used as a component of a liquid crystal composition. Liquid crystal compounds, liquid crystal compositions, and liquid crystal display devices are sometimes referred to as compounds, compositions, and devices, respectively.

In this specification, "liquid crystal element" is a general term for liquid crystal display panels and liquid crystal display modules. The upper limit temperature of the nematic phase is the phase transition temperature of the nematic phase-isotropic phase, and is sometimes referred to as the clearing point or the upper limit temperature. The lower limit temperature of the nematic phase is sometimes referred to as the lower limit temperature.

In this specification, the compound represented by formula (1) is sometimes referred to as compound (1). This abbreviation is sometimes also applied to compounds represented by formula (2) and the like. In the chemical formula, symbols such as A ¹¹ , A ¹² surrounded by a hexagon correspond to ring structure A ¹¹ , ring structure A ¹² and the like, respectively. These are sometimes referred to as "ring A ¹¹ ,""ring A ¹² ." The so-called "ring structure" refers to a cyclic group, including a benzene ring, a naphthalene ring, a cyclohexene ring, a bicyclooctane ring or a cyclohexane ring and the like. Here, a ring structure including multiple rings such as a condensed polycyclic hydrocarbon such as a naphthyl ring or a bridged hydrocarbon such as a bicyclooctane ring is counted as one ring structure. Although multiple identical symbols such as ring A ^k1 and ring Y ^k1 are described in the same formula or different formulas, these symbols may be the same or different. The wavy line in the chemical formula indicates a bonding site.

"At least one" means not only the position but also the number, but does not include the case where the number is 0. The expression that at least one A may be substituted by B, C or D means that in addition to the case where at least one A is substituted by B, at least one A is substituted by C and at least one A is substituted by D, it also includes the case where a plurality of A are substituted by at least two of B to D. For example, the alkyl group in which at least one _-CH2- may be substituted by -O- or -CH=CH- includes alkyl, alkenyl, alkoxy, alkoxyalkyl, alkoxyalkenyl, alkenyloxyalkyl and the like. Furthermore, in the present invention, the case where two consecutive _-CH2- are substituted by -O- to -OO- is not preferred. Moreover, the case where the terminal _-CH2- in the alkyl group is substituted by -O- is also not preferred. In addition, in this specification, "%" means "% by weight" unless otherwise specified. [Effects of the Invention]

The liquid crystal composition containing chiral components and non-chiral components in the embodiment of the present invention can be preferably used for liquid crystal elements due to its good light resistance. The chiral compound in the embodiment of the present invention has a large HTP and high compatibility with non-chiral components, so the pitch can be adjusted to less than 0.5 μm. In addition, the liquid crystal phase can be displayed in a wide temperature range including low temperature. Furthermore, effective light scattering can be obtained, so the liquid crystal element obtained using the liquid crystal composition is low-voltage driven, and the change in light scattering when voltage is applied and when no voltage is applied is large, so it can be applied to liquid crystal devices showing high contrast. In order to better bring out the performance of the liquid crystal composition in the embodiment of the present invention, it is preferably combined with chiral nematic liquid crystal or cholesterol liquid crystal. In the liquid crystal composition of the embodiment of the present invention, in addition to the chiral compound represented by formula (K1), materials generally recognized as liquid crystal materials in the art and chiral compounds other than the chiral compound represented by formula (K1) may be appropriately added.

In addition, an optically isotropic liquid crystal composition can be efficiently prepared in a short time. The liquid crystal composition of the embodiment of the present invention, the liquid crystal composition showing an optically isotropic liquid crystal phase, and the polymer/liquid crystal composite material show a relatively large Kerr coefficient. That is, a relatively low driving voltage is displayed. The liquid crystal composition showing an optically isotropic liquid crystal phase and the polymer/liquid crystal composite material of the embodiment of the present invention have a fast response speed. The liquid crystal composition showing an optically isotropic liquid crystal phase and the polymer/liquid crystal composite material of the embodiment of the present invention can be used in a wide temperature range. Moreover, the liquid crystal composition showing an optically isotropic liquid crystal phase and the polymer/liquid crystal composite material of the embodiment of the present invention can be preferably used in liquid crystal elements such as liquid crystal display elements for high-speed response purposes based on these effects.

1. Liquid crystal composition of the present invention The first aspect of the present invention is a liquid crystal composition that can be used in a liquid crystal element driven by a chiral nematic phase or an optically isotropic phase. The liquid crystal composition of the embodiment of the present invention has a compound represented by formula (K1) as a chiral component and has an achiral component. Here, the chirality of the chiral component is not limited. The liquid crystal composition of the embodiment of the present invention preferably exhibits a chiral nematic phase or an optically isotropic phase. The compounds contained in the liquid crystal composition of the embodiment of the present invention are generally synthesized by a known method, such as a method of reacting the necessary components at a high temperature. In addition, even if the elements constituting the compounds of the liquid crystal composition of the embodiment of the present invention are analogs including isotopic elements, they can be used as long as there is no significant difference in their physical properties. In the liquid crystal composition of the embodiment of the present invention, the content of the chiral component (K) is usually 0.1 wt % to 30 wt %, preferably 0.1 wt % to 10 wt %.

1.1 Chiral Nematic Phase The liquid crystal composition of the embodiment of the present invention includes a chiral nematic phase. The chiral nematic phase can be obtained by adding a small amount of chiral compound to a non-chiral component of a compound exhibiting a nematic phase. In order to obtain a sufficient contrast between opacity and transparency caused by light scattering, the helical pitch (hereinafter sometimes referred to as "pitch") of the liquid crystal composition used in the embodiment of the present invention is preferably 0.3 μm to 5 μm. Generally speaking, in the range of helical pitch of 0.3 μm to 0.5 μm, the transparency caused by light scattering is relatively high, and in the range of helical pitch of 0.6 μm to 5 μm, the opacity caused by light scattering is relatively high. When used in a light-adjusting material, the compound (K1) has a large HTP and is highly compatible with the compound (1-A) or the compound (1-B), so that a pitch of 0.5 μm or less can be adjusted. Furthermore, since effective light scattering can be obtained and stability with respect to light is high, a liquid crystal element that can achieve high contrast and high light resistance by low voltage driving can be provided.

1.2 Optically isotropic liquid crystal phase The liquid crystal composition of the embodiment of the present invention includes a liquid crystal phase having optical isotropy. Here, the liquid crystal composition having optical isotropy means that the liquid crystal molecules are arranged isotropically from a macroscopic point of view, thus showing optical isotropy, but from a microscopic point of view, there is a liquid crystal order. In addition, in this specification, the so-called "optically isotropic liquid crystal phase" means a liquid crystal phase that does not show fluctuations but shows optical isotropy, such as a phase showing a platelet structure (blue phase in a narrow sense). Generally speaking, blue phases are classified into three types (blue phase I, blue phase II, blue phase III), all of which are optically active and isotropic. In the blue phase of blue phase I or blue phase II, two or more diffracted lights caused by Bragg reflection from different lattice planes can be observed. In the liquid crystal composition of the embodiment of the present invention, in order to show an optically isotropic liquid crystal phase, the helical pitch based on the liquid crystal order from a microscopic point of view is preferably less than 1000 nm. The longer the pitch becomes, the greater the electro-induced birefringence in the optically isotropic liquid crystal phase becomes. Therefore, as long as the desired optical properties (transmittance, diffraction wavelength, etc.) are met, the pitch can be set to be long to increase the electro-induced birefringence. In addition, in this specification, the so-called "non-liquid crystal isotropic phase" is an isotropic phase generally defined, that is, a disordered phase, and even if a region where the local order parameter is not zero is generated, the reason is also due to the shaking of the isotropic phase. For example, the isotropic phase shown on the high temperature side of the nematic phase is equivalent to the non-liquid crystal isotropic phase in this specification. The same definition applies to the chiral liquid crystal compounds in this specification.

1.3 Chiral component (K) 1.3.1 Properties of the chiral compound (K1) The chiral component (K) contained in the liquid crystal composition of the embodiment of the present invention includes a compound represented by the following formula (K1). In formula (K1), R ^k1 is independently fluorine, chlorine, -C≡N, an alkyl group having 1 to 10 carbon atoms, or an alkenyl group having 2 to 10 carbon atoms. In the alkyl group, at least one -CH ₂ - may be substituted by -O-, but two consecutive -CH ₂ - groups may not be substituted by -O-. In these groups, at least one hydrogen group may be substituted by a halogen. Preferred examples are hydrogen, fluorine, an alkyl group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, and an alkoxy group having 1 to 5 carbon atoms. Y ^k1 is independently a single bond, or -(CH ₂ ) _n -, where n is an integer of 1 to 20. Preferred examples are single bonds, -CH ₂ CH ₂ -, -(CH ₂ ) ₄ -, or -(CH ₂ ) ₆ -. When n is small, HTP is large, and when n is large, compatibility tends to be good. nk1 and nk2 are each independently integers of 0 to 4. Preferred examples are 0, 1, or 2. When nk1 is 1 or 2, compatibility in the liquid crystal composition tends to be good. Rod ^k1 is a partial structural formula (Rod1), wherein R ^k2 is hydrogen, fluorine, chlorine, -C≡N, an alkyl group having 1 to 10 carbon atoms, or an alkenyl group having 2 to 10 carbon atoms, at least one -CH ₂ - in the alkyl group may be substituted by -O-, but two consecutive -CH ₂ - groups may not be substituted by -O-, and at least one hydrogen in these groups may be substituted by a halogen. Preferred examples are an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 7 carbon atoms, or an alkoxy group having 1 to 7 carbon atoms.

In addition, as a partial structural formula, a preferred example is (Rod1-1) or (Rod1-2). When (Rod1-1) is used, HTP is high, and when (Rod1-2) is used, compatibility in a liquid crystal composition is relatively good. Ring A ^k1 , Ring A ^k2 , and Ring A ^k3 are independently 1,4-cyclohexylene, 1,4-phenylene, 1,4-phenylene in which at least one hydrogen is substituted with fluorine, 1,3-dioxane-2,5-diyl, tetrahydropyran-2,5-diyl, or pyrimidine-2,5-diyl. Preferred examples are 1,4-cyclohexylene, 1,4-phenylene, 1,4-phenylene in which one or two hydrogen radicals are substituted with fluorine, or 1,3-dioxane-2,5-diyl. The compounds have a large HTP and good compatibility with other liquid crystal compositions.

^Zk1 , ^Zk2 , and ^Zk3 are independently single bonds, _-CH2CH2- , _-COO- , -OCO-, -OCH2-, _-CH2O- , _-CF2O- , -OCF2-, -CH=CH-, _-CF2CF2- , -CF=CF-, or _-C≡C- ; preferred examples are single bonds, -COO-, -OCO-, alkylene groups having 1 to 10 carbon atoms, _-CH2O- , _{-OCH2- , -CF2O-} , or _-OCF2- . In the case of these substituents, the compatibility of HTP with the liquid crystal composition is well balanced. mk1 and mk2 are independently integers of 0 or _1. The compound with mk1+mk2 being 1 has good compatibility with the liquid crystal composition. In addition, compounds with mk1+mk2 of 2 tend to have a large HTP.

When there are multiple identical symbols such as R ^k1 , R ^k2 , A ^k1 , Z ^k1 , nk1 , or nk2, they may be identical or different. Furthermore, the alkyl group having 1 to 10 carbon atoms is more preferably an alkyl group having 1 to 6 carbon atoms. Examples of the alkyl group are not limited, and include methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, t-butyl, pentyl, hexyl, and dodecyl.

A preferred example of the chiral compound represented by formula (K1) is a compound represented by formula (K1-1), and Rod ^k1 is (Rod1-1). In formula (K1-1), more preferred examples are compounds represented by Rod ^k1 (Rod1-1C), (Rod1-1D), (Rod1-1F), and (Rod1-1G). All of them have high HTP and good compatibility in liquid crystal compositions.

In general, the content of chiral components in the liquid crystal composition of the embodiment of the present invention is preferably 0.1 wt% to 20 wt%, and particularly preferably 1 wt% to 10 wt%. Liquid crystal compositions containing chiral components within these ranges tend to have an optically isotropic liquid crystal phase. Using the liquid crystal composition of the embodiment of the present invention, the polymer/liquid crystal composite described below can be obtained. When the polymer/liquid crystal composite is used as a dimming material, in order to obtain a sufficient contrast between opacity and transparency brought about by light scattering, the helical pitch in the liquid crystal composition is particularly preferably in the range of 0.3 μm to 0.5 μm, 0.6 μm to 5 μm. In addition, when the liquid crystal composition of the embodiment of the present invention is used in a liquid crystal display element, it is preferred to adjust the concentration of the chiral component so that no diffraction or reflection is substantially confirmed in the visible area. Furthermore, the chiral compound constituting the chiral component contained in the liquid crystal composition of the embodiment of the present invention may be one or more. Furthermore, when two or more chiral compounds are used, it is preferred to use chiral compounds with the same twisting direction so as not to cancel out the HTP. It is also possible to use a combination of chiral compounds with opposite twisting directions for the purpose of adjusting the temperature dependence of the helical pitch.

1.3.2 Synthesis of Chiral Compound (K1) Next, the synthesis of the compound represented by formula (K1) is described. Compound (K1) can be synthesized by appropriately combining methods in organic synthetic chemistry. Methods for introducing target terminal groups, rings, and bonding groups into starting materials are described in: "Organic Syntheses" (John Wiley & Sons, Inc), "Organic Reactions" (John Wiley & Sons, Inc), "Comprehensive Organic Synthesis" (Pergamon Press), New Experimental Chemistry Lectures (Maruzen), etc. There are many methods for synthesizing compound (K1), and appropriate synthesis can be performed by referring to the examples in this manual or books. First, an example of a method for producing compound (15) as a common intermediate will be described using a scheme.

(1) Preparation and synthesis of anthracene derivatives (15) [Chemistry 17]

Anthracene derivatives can be synthesized from commercially available compounds by general organic synthesis methods. Examples of commercially available compounds include compound (ref.001) and compound (ref.002). When R ^k1 is an alkyl group, alkenyl group, alkynyl group, or alkoxy group, for example, an alkyl halide can be allowed to react with compound (101) in the presence of an appropriate lithium reagent or metal catalyst to undergo coupling reaction, thereby obtaining compound (102). Similarly, when R ^k1 is fluorine, compound (103) can be obtained by reacting compound (101) with a fluorinating agent such as N-benzenesulfonimide, and when R ^k1 is -CN, compound (104) can be obtained by reacting compound (101) with a cyanide such as copper cyanide.

(2) Synthesis of Compound (K1-1) and Compound (K1-2) [Chemistry 18] [Chemistry 19]

Trans-butylenediyl chloride (111) is commercially available. In addition, the (S) form or (R) form of optically active ethyl lactate (112) is commercially available. Trans-butylenediyl chloride (111) and a base such as triethylamine can be reacted with optically active ethyl lactate (112) to obtain compound (113). Subsequently, compound (114) can be stereoselectively prepared by subjecting compound (113) to a Diels-Alder reaction with an anthracene derivative (114), and compound (115) can be derived by reacting an excess amount of base. When dicyclohexyl carbodiimide (DCC) and dimethylamino pyridine (DMAP) are added to compound (115) and a suitable phenol derivative (Rod ^k1 -OH) is allowed to react, compound (K1-1) of the embodiment of the present invention can be obtained. Furthermore, when a reducing agent such as lithium aluminum hydride (LAH) is allowed to act on compound (K1-1), compound (K1-2) can be obtained.

Next, an example of a method for producing a bonding group Z ^k1 is described using a flow chart. In this process, MSG ¹ or MSG ² is a monovalent organic group having at least one ring. Multiple MSG ¹ (or MSG ² ) used in the process may be the same or different. Compounds (1A) to (1K) are equivalent to compound (K1).

(I) Generation of single bonds [Chemistry 20] Compound (1A) is prepared by reacting arylboronic acid (21) with compound (22) synthesized by a known method in the presence of a carbonate aqueous solution and a catalyst such as tetrakis(triphenylphosphine)palladium. Compound (1A) can also be prepared by reacting compound (23) synthesized by a known method with n-butyl lithium, followed by a reaction with zinc chloride, and then reacting compound (22) in the presence of a catalyst such as dichlorobis(triphenylphosphine)palladium.

(II) Formation of -CF ₂ O- and -OCF ₂ - [Chemistry 21] Compound (1B) is treated with a sulfiding agent such as Lawesson's reagent to obtain compound (26). Compound (26) is fluorinated with hydrogen fluoride pyridine complex and N-bromosuccinimide (NBS) to synthesize compound (1C) having -CF2O- (see M. Kuroboshi et al., "Chem. Lett.", 1992, No. 827). Compound ( ₂₆ ) is also fluorinated with (diethylamino)sulfur trifluoride (DAST) to synthesize compound (1C) (see WH Bunnelle et al., "Journal of Organic Chemistry, J. Org. Chem.", 1990, No. 55, p. 768). Compounds having -OCF ₂ - can also be synthesized using this method. These bonding groups can also be generated using the method described in "Angew. Chem. Int. Ed." by Peer. Kirsch et al. (2001, Vol. 40, p. 1480).

(III) Formation of -CH=CH- [Chemistry 22] Compound (22) is treated with n-butyl lithium and then reacted with formamide such as N,N-dimethylformamide (DMF) to obtain aldehyde (28). Phosphonium salt (27) synthesized by a known method is treated with a base such as potassium tert-butoxide to produce a phosphorus ylide, which is reacted with aldehyde (28) to synthesize compound (1D). Depending on the reaction conditions, a cis isomer may be generated, and the cis isomer may be isomerized to a trans isomer by a known method as needed.

(IV) Formation of -(CH ₂ ) ₂ - [Chemistry 23] Compound (1E) is synthesized by hydrogenating compound (1D) in the presence of a catalyst such as palladium-carbon.

Formation of (V)-(CH ₂ ) ₄ -[Chemical 24] A compound having -(CH ₂ ) ₂ - and -CH=CH- is obtained by using a phosphonium salt (29) instead of a phosphonium salt (27) according to the method of item (III) or item (IV). This compound is subjected to catalytic hydrogenation to synthesize a compound (1F).

(VI) Formation of -C≡C- [Chemistry 25] Compound (23) is reacted with 2-methyl-3-butyn-2-ol in the presence of a catalyst of palladium dichloride and copper halide, and then deprotected under alkaline conditions to obtain compound (30). Compound (30) is reacted with compound (22) in the presence of a catalyst of palladium dichloride and copper halide to synthesize compound (1G).

(VII) Formation of -CF=CF- [Chemistry 26] Compound (22) is treated with n-butyl lithium and then reacted with tetrafluoroethylene to obtain Compound (31). Compound (1H) is synthesized by treating Compound (22) with n-butyl lithium and then reacting with Compound (31).

(VIII) Formation of -CH ₂ O- or -OCH ₂ - [Chemistry 27] Compound (28) is reduced with a reducing agent such as sodium borohydride to obtain compound (32). Compound (32) is halogenated with hydrobromic acid to obtain compound (33). Compound (33) is reacted with compound (25) in the presence of potassium carbonate to synthesize compound (1J).

(IX) Formation of -(CH ₂ ) ₃ O- or -O(CH ₂ ) ₃ - [Chemistry 28] Compound (1K) is synthesized according to the method of item (VIII) using compound (34) instead of compound (32).

(X)-(CF ₂ ) ₂ - is prepared by fluorinating diketone (-COCO-) with sulfur tetrafluoride in the presence of a hydrogen fluoride catalyst according to the method described in "Journal of the American Chemical Society (J.Am.Chem.Soc.)", Vol. 123, 2001, p. 5414, to obtain a compound having -(CF ₂ ) ₂ -.

In the liquid crystal composition of the embodiment of the present invention, the chiral compound (K1) is added as the chiral component (K), and at least one of the compounds represented by (K2) to (K8) may be included.

1.4 Non-chiral component The non-chiral component constituting the liquid crystal composition of the embodiment of the present invention includes at least one non-chiral compound and exhibits a liquid crystal phase. The non-chiral component containing at least one non-chiral compound represented by formula (1-A) or formula (1-B) is suitable as a liquid crystal component for use as a liquid crystal element. In the liquid crystal composition of the embodiment of the present invention, in addition to the chiral compound represented by formula (K1) as the chiral component (K) and at least one non-chiral compound represented by formula (1-A) or formula (1-B), materials generally recognized as liquid crystal materials in the art may be further added and used as other liquid crystal materials. In addition, in the liquid crystal composition of the embodiment of the present invention, the content of the non-chiral component (T) is generally 80% by weight to 99.9% by weight, preferably 90% by weight to 99.9% by weight. In the liquid crystal composition of the embodiment of the present invention, the content of the compound represented by formula (1-A) or formula (1-B) in the non-chiral component (T) is usually 50% by weight to 100% by weight, preferably 90% by weight to 100% by weight. Furthermore, in the liquid crystal composition of the embodiment of the present invention, the content of the compound represented by formula (1-A) in the non-chiral component (T) is 50% by weight to 100% by weight, in which case an optically isotropic liquid crystal phase can be exhibited.

1.4.1 Structure of the compound represented by formula (1-A) or (1-B) [Chemical 29]

In the formula (1-A) and the formula (1-B), R ¹¹ and R ¹² are independently hydrogen, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, or an alkenyl group having 2 to 10 carbon atoms. In the alkyl group and the alkenyl group, at least one -CH ₂ - may be substituted by -O-, but two consecutive -CH ₂ - groups may not be substituted by -O-. In these groups, at least one hydrogen may be substituted by a halogen. In such R ¹¹ and R ¹² , an alkyl group having 1 to 10 carbon atoms or an alkenyl group having 2 to 10 carbon atoms is preferred. An alkyl group having 2 to 8 carbon atoms or an alkenyl group having 2 to 8 carbon atoms is more preferred. The preferred stereo configuration of -CH=CH- in the alkenyl group depends on the position of the double bond. In alkenyl groups having a double bond at an odd position such as -CH=CHCH ₃ , -CH=CHC ₂ H ₅ , -CH=CHC ₃ H ₇ , -CH=CHC ₄ H ₉ , -C ₂ H ₄ CH=CHCH ₃ , and -C ₂ H ₄ CH=CHC ₂ H ₅ , a trans configuration is preferred. In alkenyl groups having a double bond at an even position such as -CH ₂ CH=CHCH ₃ , -CH ₂ CH=CHC ₂ H ₅ , and -CH ₂ CH=CHC ₃ H ₇ , a cis configuration is preferred. Alkenyl compounds having a preferred stereo configuration have a high upper temperature limit or a wide temperature range of a liquid crystal phase. "Molecular Crystals and Liquid Crystals (Mol. Cryst. Liq. Cryst.)" 1985, No. 131, p. 109 and "Molecular Crystals and Liquid Crystals (Mol. Cryst. Liq. Cryst.)" 1985, No. 131, p. 327 have detailed descriptions. Ring ^A11 , Ring ^A12 , and Ring ^A13 are independently 1,4-cyclohexylene, 1,4-phenylene, 1,4-phenylene in which at least one hydrogen is substituted with fluorine, 1,3-dioxane-2,5-diyl, tetrahydropyran-2,5-diyl, or pyrimidine-2,5-diyl. Ring ^A11 , Ring ^A12 , and Ring ^A13 are each independently preferably 1,4-phenylene which may be substituted with a halogen, 1,3-dioxane-2,5-diyl, tetrahydropyran-2,5-diyl, or 1,4-cyclohexylene. ^Z11 , ^Z12 , and ^Z13 are each independently a single bond, _-CH2CH2- , _-COO- , -OCO-, -CH2O-, _-OCH2- , -CF2O-, _-OCF2- , -CH= _CH- , -CF= _CF- , or -C≡C-. Z ¹¹ , Z ¹² , and Z ¹³ are preferably a single bond, -CH ₂ CH ₂ -, -CH=CH-, -C≡C-, -COO-, -CF ₂ O-, -OCF ₂ -, -CH ₂ O-, or -OCH ₂ -, and among these, a single bond, -COO-, or -CF ₂ O- is particularly preferred. Among these bonds, in a double bond group such as -CH=CH-, -CF=CF-, -CH=CH-(CH ₂ ) ₂ -, and -(CH ₂ ) ₂ -CH=CH-, the stereo configuration is preferably a trans configuration rather than a cis configuration. X ¹¹ is fluorine, chlorine, -SF ₅ , -CHF ₂ , -CF ₃ , -CF ₂ CH ₂ F, -CF ₂ CHF ₂ , -CF ₂ CF ₃ , -(CF ₂ ) ₃ -F, -CF ₂ CHFCF ₃ , -CHFCF ₂ CF ₃ , -(CF ₂ ) ₄ -F, -(CF ₂ ) ₅ -F, -OCHF ₂ , -OCF ₃ , -OCF ₂ CH ₂ F , -OCF ₂ CHF ₂ , -OCH ₂ CF ₃ , -OCF ₂ CF ₃ , -O-(CF ₂ ) ₃ -F, -OCF ₂ CHFCF ₃ , -OCHFCF ₂ CF ₃ , -O-(CF ₂ ) ₄ -F, -O-(CF ₂ ) ₅ -F, -CH=CF ₂ , -CH=CHCF ₃ , or -CH=CHCF ₂ CF ₃ . Preferred examples of X ¹¹ are fluorine, chlorine, -C≡N, -N=C=S, -CF ₃ , -CHF ₂ , -OCF ₃ , and -OCHF ₂ . Optimum examples of X ¹ are fluorine, chlorine, -C≡N, -N=C=S, -CF ₃ , and -OCF ₃ . L ¹¹ and L ¹² are independently hydrogen or fluorine, L ¹³ and L ¹⁴ are independently hydrogen, fluorine, chlorine, or -C≡N, but L ¹³ and L ¹⁴ may not both be hydrogen. Among them, it is preferred that either L ¹¹ or L ¹² is fluorine, and it is preferred that L ¹³ and L ¹⁴ are each independently hydrogen, fluorine or -C≡N. S ¹¹ is hydrogen or methyl. m and n are each independently 0 or 1.

The compound represented by the formula (1-A) is particularly preferably any one of the compounds represented by the following formulas (1-A-01) to (1-A-22). [Chemistry 31] [Chemistry 32]

The compound represented by the formula (1-B) is particularly preferably any one of the compounds represented by the following formulas (1-B-01) to (1-B-22). [Chemistry 34]

(In formulas (1-A-01) to (1-A-22), and (1-B-01) to (1-B-22), R ¹¹ and R ¹² are hydrogen, alkyl having 1 to 8 carbon atoms, alkenyl having 2 to 8 carbon atoms, or alkoxy having 1 to 8 carbon atoms, A ¹¹ and A ¹² are 1,4-cyclohexylene, 1,3-dioxane-2,5-diyl, or tetrahydropyran-2,5-diyl, X ¹¹ is fluorine, chlorine, -CF ₃ , -CHF ₂ , -CH ₂ F, -OCF ₃ , -OCHF ₂ , -OCH ₂ F, -CN, or -C═C-CF ₃ , and (F) is hydrogen or fluorine)

1.3.2 Properties of the achiral compounds represented by formula (1-A) and formula (1-B) Compound (1-A) is a compound having a positive dielectric anisotropy. On the other hand, compound (1-B) is a compound having a negative dielectric anisotropy. By appropriately selecting the left terminal group R ¹¹ , the right terminal group X ¹¹ and the right terminal group R ¹² , the types of rings A ¹¹ to A ¹³ , the bonding groups Z ¹¹ to Z ¹³ , the groups on the terminal phenylene rings and their substitution positions (L ¹¹ , L ¹² , L ¹³ , L ¹⁴ , and S ¹¹ ), the combination of bonding groups Z ¹¹ to Z ¹³ , m and n, etc., the physical properties of the achiral component (T) such as the clearing point, refractive index anisotropy and dielectric anisotropy can be adjusted. The following describes the general relationship between the left terminal group R ¹¹ , the right terminal group X ¹¹ and the right terminal group R ¹² , rings A ¹¹ to A ¹³ , bonding groups Z ¹¹ to Z ¹³ , L ¹¹ to L ¹⁴ , the types of combinations of m and n, and the physical properties of compounds (1-A) and (1-B).

When R ¹¹ or R ¹² is a linear chain, the temperature range of the liquid crystal phase of compound (1-A) and compound (1-B) is wide and the viscosity is low. On the other hand, when R ¹¹ or R ¹² is a branched chain, compound (1-A) and compound (1-B) have good compatibility in the liquid crystal composition. When R ¹¹ or R ¹² is an alkenyl group, the viscosity is low and the compatibility in the liquid crystal composition is good. When R ¹¹ or R ¹² is an alkoxy group, the dielectric anisotropy is large and the compatibility in the liquid crystal composition is good.

The more aromatic rings are contained in Ring A ¹¹ to Ring A ¹³ , the greater the refractive index anisotropy of Compound (1-A) and Compound (1-B). When Ring A ¹¹ to Ring A ¹³ are 1,4-phenylene, 1,3-dioxane-2,5-diyl, tetrahydropyran-2,5-diyl, or pyrimidine-2,5-diyl, respectively, in which at least one hydrogen is substituted with fluorine, it is effective in showing a large dielectric anisotropy. When Ring A ¹¹ to Ring A ¹³ are 1,4-cyclohexylene or tetrahydropyran-2,5-diyl, respectively, it helps Compound (1-A) or Compound (1-B) to show good compatibility. When the bonding group Z ¹¹ , the bonding group Z ¹² , and the bonding group Z ¹³ are respectively a single bond, -CH ₂ CH ₂ -, -CH=CH-, -CF ₂ O-, -OCF ₂ -, -CH ₂ O-, -OCH ₂ -, -CF=CF-, -(CH ₂ ) ₃ -O-, -O-(CH ₂ ) ₃ -, -(CH ₂ ) ₂ -CF ₂ O-, -OCF ₂ -(CH ₂ ) ₂ -, or -(CH ₂ ) ₄ -, the viscosity of the compound (1-A) or the compound (1-B) is small. In addition, when the bonding group Z ¹¹ , the bonding group Z ¹² , and the bonding group Z ¹³ are single bonds, -(CH ₂ ) ₂ -, -CF ₂ O-, -OCF ₂ -, or -CH=CH-, the viscosity of the compound (1-A) or the compound (1-B) becomes further reduced. When the bonding group Z ¹¹ , the bonding group Z ¹² , and the bonding group Z ¹³ are -C≡C-, the refractive index anisotropy of the compound (1-A) or the compound (1-B) is large. When the bonding group Z ¹¹ , the bonding group Z ¹² , and the bonding group Z ¹³ are -COO- or -CF ₂ O-, the dielectric anisotropy of the compound (1-A) or the compound (1-B) is large. When Z ¹¹ , Z ¹² , and Z ¹³ are a single bond, -(CH ₂ ) ₂ -, -CH ₂ O-, -CF ₂ O-, -OCF ₂ -, or -(CH ₂ ) ₄ -, respectively, compound (1-A) or compound (1-B) is relatively stable in chemical properties and is not easily deteriorated. Generally speaking, when the refractive index anisotropy or dielectric anisotropy is large, the driving voltage of the liquid crystal element of the embodiment of the present invention tends to be low, and the response speed is fast if the viscosity is low. When X ¹¹ is fluorine, chlorine, -SF ₅ , -CHF ₂ , -CF ₃ , -CH ₂ F, -OCF ₃ , -OCHF ₂ , or -OCH ₂ F, compound (1-A) has a large dielectric anisotropy. When X ¹¹ is fluorine or -OCF ₃ , the chemical properties are stable. When L ¹¹ and L ¹² are both fluorine, and X ¹¹ is fluorine, chlorine, -SF ₅ , -CF ₃ , -CHF ₂ , -CH ₂ F, -OCF ₃ , -OCHF ₂ , or -OCH ₂ F, the dielectric anisotropy of the compound (1-A) is very large. In addition, when L ¹¹ is fluorine and L ¹² is hydrogen, and X ¹¹ is -CF ₃ or -OCF ₃ ; when L ¹¹ and L ¹² are both fluorine and X ¹¹ is -CF ₃ or -OCF ₃ ; or when L ¹¹ , L ¹² and X ¹¹ are all fluorine, the dielectric anisotropy of the compound (1-A) is large, the temperature range of the liquid crystal phase is wide, and the chemical properties are stable and it is not easy to cause degradation. In addition, when ^{L 13 and} L ¹⁴ are both fluorine and R ¹² is an alkoxy group, the dielectric anisotropy of the compound (1-B) is ^large and the temperature range of the liquid crystal phase is wide. In addition, when L ¹³ is fluorine and R ¹² is an alkyl group, the dielectric anisotropy of the compound (1-B) is large, the chemical properties are stable and it is not easy to deteriorate. The larger the m+n, the higher the transparent point of the compound, and the smaller the m+n, the lower the melting point of the compound (1-A).

1.3.3 Other achiral components For the purpose of optimizing the properties of the liquid crystal composition of the embodiment of the present invention, a compound represented by the following formula (1-C) can be used as an achiral component as necessary.

In the formula (1-C), R ¹¹ and R ¹² are independently hydrogen, an alkyl group having 1 to 8 carbon atoms, an alkenyl group having 2 to 8 carbon atoms, or an alkoxy group having 1 to 8 carbon atoms; Z ¹¹ and Z ¹² are independently a single bond, -CH ₂ CH ₂ -, -COO-, -OCO-, -CH ₂ O-, -OCH ₂ -, -CF ₂ O-, -OCF ₂ -, -CH=CH-, -CF=CF-, or -C≡C-; Ring A ¹¹ and Ring A ¹² are independently 1,4-cyclohexylene, 1,4-phenylene, 1,4-phenylene in which at least one hydrogen atom is substituted with fluorine, 1,3-dioxane-2,5-diyl, tetrahydropyran-2,5-diyl, or pyrimidine-2,5-diyl; p is 1, 2, or 3.

Compound (1-C) is a compound with low dielectric anisotropy and has the characteristic of low viscosity. The general relationship between the terminal groups R ¹¹ and R ¹² , ring A ¹¹ and A ¹² , and the types of combinations of bonding groups Z ¹¹ and Z ¹² of compound (1-C) and the physical properties is similar to that described for compounds (1-A) and (1-B). Regarding p, when p is 1, the clearing point is low and the viscosity is low. When p is 2, the balance between the clearing point and the viscosity is good, and when p is 3, the clearing point is high.

The compound represented by the formula (1-C) is particularly preferably any one of the compounds represented by the following formulas (1-C-01) to (1-C-14).

In formula (1-C-01) to formula (1-C-14), R ¹¹ and R ¹² are each independently hydrogen, an alkyl group having 1 to 8 carbon atoms, an alkenyl group having 2 to 8 carbon atoms, or an alkoxy group having 1 to 8 carbon atoms; A ¹¹ and A ¹² are each independently 1,4-cyclohexylene, 1,3-dioxane-2,5-diyl, or tetrahydropyran-2,5-diyl; and (F) is hydrogen or fluorine.

2. Monomer/liquid crystal mixture containing liquid crystal composition and polymerizable monomer, and polymer/liquid crystal composite material The second aspect of the present invention is a mixture of a liquid crystal composition having a chiral nematic phase or an optically isotropic liquid crystal phase and a polymerizable monomer. Furthermore, in this specification, "polymerizable monomer" is a concept that also includes macromonomers or oligomers. When the monomer/liquid crystal mixture containing the liquid crystal composition and the polymerizable monomer is used as a material for a liquid crystal element having a dimming layer such as a dimming window, a liquid crystal element that can be driven at a lower voltage and has a higher contrast characteristic can be produced. In order to control the structure of the transparent material that becomes a part of the dimming layer of the liquid crystal element described later according to the purpose, it is preferred to use a monomer/liquid crystal mixture in the embodiment of the present invention. The third aspect of the present invention is a polymer/liquid crystal composite material, which can be produced, for example, by polymerizing the monomer/liquid crystal mixture containing the liquid crystal composition and the polymerizable monomer of the second aspect of the present invention. The polymer/liquid crystal composite material of the embodiment of the present invention is preferably a liquid crystal phase having a chiral nematic phase or an optically isotropic phase. The so-called polymer/liquid crystal composite material is not particularly limited as long as it is a composite material containing both a liquid crystal composition and a polymer compound, and may also be a state in which a part or all of the polymer is not dissolved in the liquid crystal composition, and the polymer and the liquid crystal composition are in a phase-separated state.

The optically isotropic polymer/liquid crystal composite material of the embodiment of the present invention can show an optically isotropic liquid crystal phase in a wide temperature range. In addition, a low driving voltage and an extremely fast response speed can be achieved, so based on these effects, it can be preferably used in liquid crystal elements for display, etc. The polymer/liquid crystal composite material showing a chiral nematic phase in a preferred embodiment of the present invention can show a chiral nematic phase in a wide temperature range. In addition, when a voltage is applied and when no voltage is applied, a sufficient contrast can be obtained between the opacity and transparency caused by light scattering.

2.1 Polymerization conditions when manufacturing polymer/liquid crystal composites The polymer/liquid crystal composites of the present invention can also be manufactured by mixing a liquid crystal composition with a polymer obtained by pre-polymerization. It is preferably manufactured by mixing low molecular weight monomers, macromonomers, oligomers, etc. (hereinafter collectively referred to as "polymerizable monomers") that become polymer materials with a liquid crystal composition and then polymerizing the mixture. In the specification of this case, the mixture containing a liquid crystal composition and a polymerizable monomer in the second aspect of the present invention is also referred to as a "monomer/liquid crystal mixture". The "monomer/liquid crystal mixture" may also contain the polymerization initiator, curing agent, catalyst, stabilizer, dichroic pigment (merocyanine, styryl, azo, azomethine, azoxy, quinophthalone, anthraquinone, tetrazine, etc.), or photochromic compound as described below as needed, within the scope of not impairing the effect of the present invention. For example, in the monomer/liquid crystal mixture of the embodiment of the present invention, the polymerization initiator may be contained in an amount of 0.1 to 20 parts by weight of the polymerizable monomer as needed.

In the case of manufacturing a polymer/liquid crystal composite material with optical isotropy, the polymerization in the monomer/liquid crystal mixture containing a liquid crystal component and a polymerizable monomer is preferably carried out on the monomer/liquid crystal mixture in a non-liquid crystal isotropic phase or an optically isotropic liquid crystal phase. That is, the polymerization temperature is preferably a temperature at which the polymer/liquid crystal composite material exhibits high transparency and isotropy. It is more preferred to terminate the polymerization at a temperature at which the mixture of the polymerizable monomer and the liquid crystal component exhibits a non-liquid crystal isotropic phase or a blue phase, and in a non-liquid crystal isotropic phase or an optically isotropic liquid crystal phase. That is, it is preferred to set the polymerization temperature such that after polymerization, the polymer/liquid crystal composite material does not substantially scatter light on the wavelength side of longer visible light and exhibits an optically isotropic state. Furthermore, when the polymer/liquid crystal composite material of the embodiment of the present invention is used as a light-adjusting layer, light may be irradiated while a voltage is applied between the transparent electrodes during the polymerization reaction.

2.2 Raw materials of polymers constituting polymer/liquid crystal composite materials As raw materials of polymers constituting polymer/liquid crystal composite materials in the embodiment of the present invention, monomers such as low molecular weight monomers, macromonomers, and oligomers can be used as polymerizable monomers. In addition, it is preferred that the obtained polymer has a three-dimensional cross-linked structure, so it is preferred to use a multifunctional monomer having two or more polymerizable functional groups as a raw material of the polymer. The polymerizable functional group is not particularly limited, and examples thereof include acrylic group, methacrylic group, glycidyl group, epoxy group, cyclobutylene oxide, vinyl group, etc. From the viewpoint of polymerization rate, acrylic group and methacrylic group are preferred. In the raw material of the polymer, if the raw material contains 10% by weight or more of a monomer containing two or more polymerizable functional groups, the polymer/liquid crystal composite material of the embodiment of the present invention is likely to show high transparency and isotropy, so it is preferred. In addition, in order to obtain a better composite material, the polymer preferably has a mesogen site, and a monomer having a mesogen site can be used as a raw material of the polymer and used in part or all of it.

2.2.1 Monomers having a mesogen site (monoreactive, direactive, and trireactive monomers) The monoreactive, direactive, or trireactive monomers having a mesogen site are not particularly limited in structure, and examples thereof include any of the compounds represented by the following formula (M1), formula (M2), or formula (M3). [Chemistry 37]

In formula (M1) to formula (M3), R ^MA is hydrogen, halogen, -CF ₃ , -OCF ₃ , -C≡N, or an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, or an alkoxycarbonyl group having 2 to 20 carbon atoms. Preferably, R ^MA is an alkyl group having 1 to 20 carbon atoms, or an alkoxy group having 1 to 20 carbon atoms. R ^MB is independently a polymerizable group of group (M3-1) to group (M3-7). [Chemistry 38]

Here, ^Rd in the groups (M3-1) to (M3-7) are independently hydrogen, halogen or alkyl groups having 1 to 5 carbon atoms, and at least one hydrogen in the alkyl groups may be substituted by a halogen. Preferred ^Rd are hydrogen, fluorine and methyl. In addition, the groups (M3-2), (M3-3), (M3-4) and (M3-7) are preferably polymerized by free radical polymerization. The groups (M3-1), (M3-5) and (M3-6) are preferably polymerized by cationic polymerization. Since the above polymerizations are all living polymerizations, the polymerization starts as long as a small amount of free radicals or cationic active species are generated in the reaction system. A polymerization initiator may be used for the purpose of accelerating the generation of active species. For example, light or heat may be used to generate active species. ^AM each independently represents an aromatic or non-aromatic 5-membered ring, 6-membered ring or condensed ring having 9 or more carbon atoms; _-CH2- in the ring may be substituted by -O-, -S-, -NH- or _-NCH3- ; -CH= in the ring may be substituted by -N=; and the hydrogen atom in the ring may be substituted by a halogen, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group. Specific examples of preferred ^AM are: 1,4-cyclohexylene, 1,4-phenylene, 1,4-cyclohexenyl, 2-fluoro-1,4-phenylene, 2,3-difluoro-1,4-phenylene, 2,5-difluoro-1,4-phenylene, 2,6-difluoro-1,4-phenylene, 2-methyl-1,4-phenylene, 2-trifluoromethyl-1,4-phenylene, 2,3-bis(trifluoromethyl)-1,4-phenylene, naphthalene-2,6-diyl, tetrahydronaphthalene-2,6-diyl, fluorene-2,7-diyl, 9-methylfluorene-2,7-diyl, 1,3-dioxane-2,5-diyl, pyridine-2,5-diyl, and pyrimidine-2,5-diyl. Furthermore, the stereo configuration of the 1,4-cyclohexylene and 1,3-dioxane-2,5-diyl groups is that the trans configuration is superior to the cis configuration. Furthermore, since 2-fluoro-1,4-phenylene and 3-fluoro-1,4-phenylene are identical in structure, the latter is not exemplified. This rule also applies to the relationship between 2,5-difluoro-1,4-phenylene and 3,6-difluoro-1,4-phenylene. Y and ^M are each independently a single bond or an alkylene group having 1 to 20 carbon atoms, in which at least one -CH ₂ - may be substituted by -O-, -S-, -CH=CH-, -C≡C-, -COO-, or -OCO-, but two oxygen atoms are not adjacent like -OO-. Preferred ^YM is a single bond, -(CH ₂ ) _{m 2} -, -O(CH ₂ ) _{m 2} -, and -(CH ₂ ) _{m 2} O- (wherein m 2 is an integer of 1 to 20). Z ^M are independently single bonds, -(CH ₂ ) _m3 -, -O(CH ₂ ) _m3 -, -(CH ₂ ) _m3 O-, -O(CH ₂ ) _m3 O-, -CH=CH-, -C≡C-, -COO-, -OCO-, -(CF ₂ ) ₂ -, -(CH ₂ ) ₂ -COO-, -OCO-(CH ₂ ) ₂ -, -CH=CH-COO-, -OCO-CH=CH-, -C≡C-COO-, -OCO-C≡C-, -CH=CH-(CH ₂ ) ₂ -, -(CH ₂ ) ₂ -CH=CH-, -CF=CF-, -C≡C-CH=CH-, -CH=CH-C≡C-, -OCF ₂ -(CH ₂ ) ₂ -, -(CH ₂ ) ₂ -CF ₂ O-, -OCF ₂ -, or -CF ₂ O- (in the above formula, m3 is an integer of 1 to 20). Preferred Z ^M is a single bond, -(CH ₂ ) _m3 -, -O(CH ₂ ) _m3 -, -(CH ₂ ) _m3 O-, -CH=CH-, -C≡C-, -COO-, -OCO-, -(CH ₂ ) ₂ -COO-, -OCO-(CH ₂ ) ₂ -, -CH=CH-COO-, -OCO-CH=CH-, -OCF ₂ -, and -CF ₂ O- (in the above formula, m3 is an integer of 1 to 20). m1 is independently an integer of 0 to 2. When the total of m1 is 1, it is a bicyclic compound having two 6-membered rings or the like. When the total number of m1 is 2 or 3, it is a tricyclic or tetracyclic compound, respectively. In addition, when there are multiple m1, two or more ^AM or two or more ^ZM may be the same or different. The same applies to ^RMB and ^YM .

The compounds represented by formula (M1) to formula (M3) have the same properties even if they contain isotopes such as ² H (deuterium) and ¹³ C in an amount larger than the naturally occurring ratio, and thus can be preferably used. More preferred examples of compound (M1) to compound (M3) are compounds represented by the following formula (M1-1) to formula (M1-16), formula (M2-1) to formula (M2-14), and formula (M3-1) to formula (M3-3). In these compounds, R ^MA , R ^MB , Z ^M , A ^M , and Y ^M have the same meanings as those of formula (M1) and formula (M2) described in the embodiments of the present invention.

The following partial structures of compounds (M1-1) to (M1-16), compounds (M2-1) to (M2-14), and compounds (M3-1) to (M3-3) are explained. Partial structure (a1) represents a 1,4-phenylene group in which at least one hydrogen atom may be substituted with a fluorine atom or a methyl atom. Partial structure (a2) represents a fluorene atom in which the hydrogen atom at the 9-position may be substituted with a methyl atom. [Chem. 39] [Chemistry 40] [Chemistry 41] [Chemistry 42] [Chemistry 43] [Chemistry 44] If necessary, a polymerizable compound other than the monomer having no mesogen site and the monomer (M1) and the monomer (M2) having a mesogen site described below may be used.

2.2.2 Monomers with polymerizable functional groups that do not have a mesogen site As monomers with polymerizable functional groups that do not have a mesogen site, for example, linear acrylates or branched acrylates having 1 to 30 carbon atoms, linear methacrylates or branched methacrylates having 1 to 30 carbon atoms, linear diacrylates or branched diacrylates having 1 to 30 carbon atoms, and linear dimethacrylates or branched dimethacrylates having 1 to 30 carbon atoms, as monomers having three or more polymerizable functional groups, Examples include glycerol propoxylate (1PO/OH) triacrylate, pentaerythritol propoxylate triacrylate, pentaerythritol triacrylate, trihydroxymethylpropane ethoxylate triacrylate, trihydroxymethylpropane propoxylate triacrylate, trihydroxymethylpropane triacrylate, di(trihydroxymethylpropane) tetraacrylate, pentaerythritol tetraacrylate, di(pentaerythritol) pentaacrylate, and di(pentaerythritol) hexaacrylate, but the monomers are not limited to these monomers.

2.3 Polymerization initiator The polymerization reaction in the production of the polymer constituting the polymer/liquid crystal composite material of the embodiment of the present invention is not particularly limited, and for example, photoradical polymerization, thermal radical polymerization, photocationic polymerization, etc. are performed. Examples of photoradical polymerization initiators that can be used in photoradical polymerization are: DAROCUR 1173 and 4265 (both trade names, BASF Japan (stock)), IRGACURE 184, 369, 500, 651, 784, 819, 907, 1300, 1700, 1800, 1850, and 2959 (all trade names, BASF Japan (stock)), etc. Examples of preferred initiators for thermal free radical polymerization that can be used in thermal free radical polymerization include: benzoyl peroxide, diisopropyl peroxydicarbonate, tert-butyl peroxy-2-ethylhexanoate, tert-butyl peroxytrimethylacetate, tert-butyl peroxide diisobutyrate, lauryl peroxide, 2,2'-Azobisisobutyric acid dimethyl (MAIB), di-tert-butyl peroxide (DTBPO), azobisisobutyronitrile (AIBN), azobis cyclohexane carbonitrile (ACN), etc. Examples of photocatalytic polymerization initiators that can be used in photocatalytic polymerization include diaryliodonium salts (hereinafter referred to as "DAS"), triarylsulfonium salts (hereinafter referred to as "TAS"), and the like. Specific examples of the trade names of the photopolymerization initiator include Cyracure UVI-6990, Cyracure UVI-6974, Cyracure UVI-6992 (trade names, UCC (stock code)), Adeka Optomer SP-150, SP-152, SP-170, SP-172 (trade names, ADEKA (stock code)), Rhodorsil Photoinitiator 2074 (trade name, Rhodia Japan (stock code)), IRGACURE 250 (trade name, BASF (stock code)), and UV-9380C (trade name, GE Toshiba Silicone (stock code)).

2.4 Hardener, etc. In the production of the polymer constituting the polymer/liquid crystal composite material of the present invention, in addition to the above-mentioned monomers and polymerization initiators, one or more other preferred components may be added, for example, one or more selected from hardeners, catalysts, stabilizers, chain transfer agents, photosensitizers, and dye crosslinkers. As the hardener, a known latent hardener commonly used as a hardener for epoxy resins may be used. Examples of latent hardeners for epoxy resins include amine hardeners, novolac resin hardeners, imidazole hardeners, and acid anhydride hardeners. In addition, a curing accelerator for accelerating the curing reaction between the polymerizable compound having a glycidyl group, an epoxy group, or an oxycyclobutyl group and the curing agent may be further used. Examples of curing accelerators include tertiary amines such as benzyldimethylamine, tris(dimethylaminomethyl)phenol, and dimethylcyclohexylamine, imidazoles such as 1-cyanoethyl-2-ethyl-4-methylimidazole and 2-ethyl-4-methylimidazole, organic phosphorus compounds such as triphenylphosphine, quaternary phosphonium salts such as tetraphenylphosphonium bromide, diazabicycloolefins such as 1,8-diazabicyclo[5.4.0]undecene-7 or its organic acid salts, quaternary ammonium salts such as tetraethylammonium bromide and tetrabutylammonium bromide, boron compounds such as boron trifluoride and triphenyl borate, etc. These curing accelerators can be used alone or in combination of two or more. In addition, for example, in order to prevent undesired polymerization during storage, it is preferred to add a stabilizer. All compounds known to those skilled in the art can be used as the stabilizer. Representative examples of stabilizers include 4-ethoxyphenol, hydroquinone, and butylated hydroxytoluene (BHT).

2.5 Content of polymerizable monomers, etc. in monomer/liquid crystal mixture The content of polymerizable monomers contained in the monomer/liquid crystal mixture of the embodiment of the present invention can be adjusted according to the purpose of use. When used as a material for forming a dimming layer of a liquid crystal element, in order to obtain a sufficient contrast between opacity and transparency due to light scattering, the monomer/liquid crystal mixture preferably contains polymerizable monomers in the range of 0.1 wt% to 50 wt%, more preferably in the range of 0.1 wt% to 40 wt%, and more preferably in the range of 0.1 wt% to 10 wt%. The content of the liquid crystal component in the polymer/liquid crystal composite material in the embodiment of the present invention varies depending on the purpose of use. As long as the polymer/liquid crystal composite material can exhibit optical isotropy or the composite material can exhibit the required helical pitch, it is preferably as low as possible, so as to achieve a reduction in the driving voltage of the polymer/composite material in the embodiment of the present invention, a faster response, an increase in electro-birefringence (Kerr coefficient), and a high contrast.

2.6 Other components The polymer/liquid crystal composite material of the present invention may also contain, for example, dichroic pigments and photochromic compounds within the scope that does not impair the effects of the present invention.

3 Liquid crystal element 3.1 Liquid crystal element using an optically isotropic liquid crystal composition The fourth aspect of the present invention is a liquid crystal element driven by an optically isotropic liquid crystal phase, comprising an optically isotropic liquid crystal composition or polymer/liquid crystal composite material (hereinafter, the liquid crystal composition and polymer/liquid crystal composite material are sometimes collectively referred to as "liquid crystal medium") of an embodiment of the present invention. As an example of the structure of a liquid crystal display element using an optically isotropic liquid crystal composition, there can be cited a structure in which the electrodes of the comb electrode substrate are arranged alternately with electrodes 1 extending from the left side and electrodes 2 extending from the right side as shown in FIG. 1. When there is a potential difference between the electrode 1 and the electrode 2, a state where electric fields in two directions, namely, the upward direction and the downward direction, can be provided on the comb electrode substrate as shown in FIG. 1 .

3.2 Liquid crystal element using a liquid crystal composition showing a chiral nematic phase The fifth aspect of the present invention is a liquid crystal element using a liquid crystal composition of an embodiment of the present invention or a polymer/liquid crystal composite material showing a chiral nematic phase as a light-adjusting material. The liquid crystal element of the embodiment of the present invention includes: two substrates having electrode layers and at least one of which is transparent, and a light-adjusting layer supported between the substrates. The light-adjusting layer includes the polymer/liquid crystal composite material described above. Here, the polymer contained in the polymer/liquid crystal composite material is preferably transparent. In addition, the polymer/liquid crystal composite material is preferably formed into a continuous layer, and it is important to form an optical edge interface by forming a disordered state of liquid crystal molecules, thereby showing light scattering. The polymer in the polymer/liquid crystal composite in the dimming layer is a polymer containing a polymerizable monomer contained in a monomer/liquid crystal mixture, but it can also be dispersed in a fiber or particle form, a film-like form in which the polymer/liquid crystal composite is dispersed in a droplet form, or a gel-like form having a three-dimensional mesh structure. In the substrate, transparent or opaque electrodes can be appropriately arranged on the entire surface or part of it according to the purpose. In addition, at least one of the substrates has transparency, but it does not necessarily have to be completely transparent. If the liquid crystal element is used to act on light passing from one side of the liquid crystal element to the other side, in this case, appropriate transparency can be given to both substrates. The substrate used in the liquid crystal element can be a solid material, such as glass, metal, etc., or a flexible material, such as a plastic film. Moreover, in the liquid crystal element, the substrates are two pieces facing each other and can be separated by an appropriate interval. In addition, an orientation film such as polyimide can be configured on the entire surface or part of at least one substrate as needed. Furthermore, between the two substrates, a spacer for maintaining the interval can also be inserted, similar to the commonly known liquid crystal element.

In the liquid crystal element of the embodiment of the present invention, the reverse mode driven liquid crystal element can be manufactured as follows, for example. That is, the monomer/liquid crystal mixture is interposed between two substrates having an electrode layer and at least one of which is transparent, and the polymerizable monomer contained in the monomer/liquid crystal mixture is polymerized by irradiating ultraviolet light through the transparent substrate or heating the transparent substrate, thereby manufacturing a liquid crystal element having a dimming layer containing a polymer and a liquid crystal compound. As an example of a reverse mode driven liquid crystal element, schematic diagrams are shown in Figures 3 (a) and 3 (b). The structure of the liquid crystal element of FIG3 (a) and FIG3 (b) includes a pair of substrates 20 with electrodes and a dimming layer 10 sandwiched between the pair of substrates 20, and the dimming layer 10 includes a polymer/liquid crystal composite material of the embodiment of the present invention, namely a liquid crystal compound 12 and a polymer 14. FIG3 (a) shows a state where no voltage is applied, and the orientation of the liquid crystal compound 12 becomes planar and light is transmitted, so the panel becomes transparent. FIG3 (b) shows a state where voltage is applied, and the orientation of the liquid crystal compound 12 becomes homogeneous and light is scattered, so the panel becomes cloudy.

In the liquid crystal element of the embodiment of the present invention, the normal mode driven liquid crystal element can be manufactured as follows. That is, the monomer/liquid crystal mixture is interposed between two substrates having an electrode layer and at least one of which is transparent, and a specific saturation voltage is applied to the liquid crystal compound while the polymerizable monomer contained in the monomer/liquid crystal mixture is polymerized by irradiating ultraviolet light through the transparent substrate or heating the transparent substrate, thereby manufacturing a liquid crystal element having a dimming layer containing a polymer and a liquid crystal compound. As an example of the normal mode driven liquid crystal element of the present invention, schematic diagrams are shown in Figures 4 (a) and 4 (b). The liquid crystal element structure of FIG. 4 (a) and FIG. 4 (b) includes a pair of substrates 20 with electrodes and a dimming layer 10 sandwiched between the pair of substrates 20, and the dimming layer 10 includes a polymer/liquid crystal composite material of the embodiment of the present invention, namely, a liquid crystal compound 12 and a polymer 14. FIG. 4 (a) shows a state where no voltage is applied, and the orientation of the liquid crystal compound 12 is focal-conic and light is scattered, so the panel is cloudy. FIG. 4 (b) shows a state where voltage is applied, and the orientation of the liquid crystal compound 12 is homeotropic and light is transmitted, so the panel becomes transparent.

Furthermore, there is no particular limitation on the method of interposing the monomer/liquid crystal mixture as the material for forming the dimming layer between the two substrates, as long as the monomer/liquid crystal mixture is injected between the substrates by a known injection technique. For example, it can be evenly applied on one of the substrates using an appropriate solution coater or spin coater, and then overlapped and pressed on the other substrate. Regarding the thickness of the light-scattering dimming layer in the liquid crystal element of the present invention, the thickness can be adjusted according to the purpose of use. In order to obtain a sufficient contrast between opacity and transparency brought about by light scattering, the thickness (substrate spacing) is preferably in the range of 2 μm to 40 μm, and particularly preferably in the range of 6 μm to 25 μm. The liquid crystal device of the embodiment of the present invention can be used for various applications such as a dimming window, a light modulation device, etc. for architectural applications such as interior decoration, and for automotive applications such as automotive leaves.

The present invention is further described in detail below by way of examples, but the present invention is not limited to these examples. In addition, unless otherwise specified, "%" means "% by weight". [Example]

In the embodiments of this specification, I represents a non-liquid crystal isotropic phase, N represents a nematic phase, N* represents a chiral nematic layer, BP represents a blue phase, and BPX represents an optically isotropic liquid crystal phase in which diffracted light of two or more colors is not observed. In this specification, the I-N phase transition point is sometimes referred to as the N-I point. The I-N* phase transition point is sometimes referred to as the N*-I point. The I-BP phase transition point is sometimes referred to as the BP-I point. In the embodiments of this specification, unless otherwise specified, the measurement and calculation of physical property values are in accordance with the methods described in the Standard of Electronic Industries Association of Japan, EIAJ・ED-2521A. Specific measurement methods, calculation methods, etc. are described below.

1) IN phase transition point (T _NI ) Place the sample on a heating plate of a melting point measuring device equipped with a polarizing microscope, and first heat the sample to a temperature at which the sample becomes a non-liquid crystal isotropic phase under crossed nicols, then cool it down at a rate of 1°C/min to fully express the chiral nematic phase or optical anisotropic phase. Measure the phase transition temperature during the process, and then heat it at a rate of 1°C/min to measure the phase transition temperature during the process. In the optically isotropic liquid crystal phase, when the phase transition point is difficult to distinguish in a dark field under crossed nicols, the phase transition temperature is measured by shifting the polarizing plate from the crossed nicol state by 1° to 10°.

2) Refractive index (n∥ and n⊥; measured at 25°C) Measured using light with a wavelength of 589 nm using an Abbe refractometer with a polarizing plate mounted on the eyepiece. After rubbing the surface of the main prism in one direction, the sample is dropped onto the main prism. The refractive index (n∥) is measured when the direction of polarization is parallel to the direction of rubbing. The refractive index (n⊥) is measured when the direction of polarization is perpendicular to the direction of rubbing.

3) Pitch (P; measured at 25°C; nm) The pitch length is measured by selective reflection (Liquid Crystal Handbook, page 196, published in 2000, Maruzen). For the selective reflection wavelength λ, the relationship <n>p/λ=1 holds. Here, <n> represents the average refractive index, which is obtained by the following formula. <n>={(n∥ ² +n⊥ ² )/2} ^1/2 . The selective reflection wavelength is measured by a microspectrophotometer (Otsuka Electronics Co., Ltd., trade name FE-3000). The pitch is calculated by dividing the obtained reflection wavelength by the average refractive index. The pitch of cholesterol liquid crystals that have reflection wavelengths in a wavelength region longer than visible light or shorter than visible light, and that are difficult to measure, is obtained by adding a chiral compound at a concentration that has a selective reflection wavelength in the visible light region (concentration C') and measuring the selective reflection wavelength (λ'), and calculating the original selective reflection wavelength (λ) based on the original concentration of the chiral compound (C) using the straight-line extrapolation method (λ=λ'×C'/C).

4) HTP (helical twist power) (measured at 25°C; μm ^-1 ) Using the average refractive index <n> and the pitch value obtained by the above method, HTP is obtained from the following formula: HTP=<n>/(λ×C). λ represents the selective reflection wavelength (nm), and C represents the concentration of the chiral compound (wt%).

5) Voltage holding ratio (VHR; measured at 60°C; %) The TN element used for measurement has a polyimide alignment film and the distance between the two glass substrates (cell gap) is 5 μm. After the sample is injected into the element, it is sealed with an adhesive that cures with ultraviolet light. The decay voltage after charging by applying a pulse voltage (5 V, 60 μs) to the TN element is measured with a high-speed voltmeter for 16.7 ms, and the area A between the voltage curve and the horizontal axis per unit cycle (30 Hz) is calculated. Area B is the area when there is no decay. The voltage holding ratio (%) is expressed as a percentage of area A relative to area B.

6) Measurement of the transmitted light intensity of the cell and calculation of the transmittance of the cell In the UV-visible spectrophotometer V650DS manufactured by JASCO Corporation, the cell is set in a manner that the light source light is perpendicular to the cell surface, and the transmitted light intensity of a wavelength of 450 nm is measured. The bandwidth of the incident light at this time is 5 nm. The transmittance/% of the cell is calculated by the transmitted light intensity of the cell as the measurement object/(the light intensity measured when the cell as the measurement object is not placed in the spectrometer) × 100. Using an electric field application unit and a bipolar power supply, the transmitted light intensity of the cell in the state where voltage is applied to the cell and the transmitted light intensity of the cell in the state where no voltage is applied are measured. The electric field applying unit used was a waveform generator 33210A manufactured by Agilent, and the bipolar power supply used was nf ELECTRONIC INSTRUMENTS 4010 manufactured by NF.

7) Calculation of contrast ratio The contrast ratio is the ratio of the transmitted light intensity under a certain condition to the transmitted light intensity under different conditions.

The ratio (percentage) of a component or liquid crystal compound is a weight percentage (wt%) based on the total weight of the liquid crystal compound. The composition is prepared by mixing the components such as the liquid crystal compound after measuring their weight. Therefore, it is easy to calculate the weight % of the component.

[Example 1] <Synthesis of Compound (K101)> [Chemical 45]

(Compound (K1-1), wherein Rodk1=Rod1-1C, nk1=nk2=0, and ^Rk2 = _C5H11 ) Compound ( _K101 ) was synthesized according to the following flow chart. [Chemical 46]

(Stage 1) Synthesis of compound (103) A toluene (150 mL) solution of compound (102) (38.6 g, 326 mmol) and triethylamine (36.4 g, 360 mmol) was prepared under nitrogen atmosphere, and compound (101) (25.0 g, 163 mmol) was slowly added dropwise at room temperature, and stirred for 1 hour while maintaining the temperature. The reaction solution was filtered to remove insoluble matter, poured into water, and toluene (100 mL) was added. The solution was washed twice with water, and the organic phase was concentrated. The residue was separated and purified by silica gel column chromatography (developing solvent: toluene/ethyl acetate = 1/1) to obtain compound (103) (15.7 g, 163 mmol).

(Stage 2) Synthesis of compound (104) In a nitrogen environment, a solution of compound (103) (29.6 g, 93.5 mmol) obtained in the previous stage and anthracene (25 g, 140 mmol) in toluene (150 mL) was heated and stirred at 110°C for 3 days. After the reaction solution was dissolved and the residual anthracene was removed, the organic phase was concentrated and the residue was separated and purified by silica gel column chromatography (developing solvent: toluene/ethyl acetate = 4/1) to obtain white crystalline compound (104) (46.2 g, 93.5 mmol).

(Stage 3) Synthesis of compound (105) In a nitrogen atmosphere, a mixed solution of compound (104) (20 g, 40.4 mmol) obtained in the previous stage in THF (100 mL)/water (100 mL) was prepared, and a methanol solution of lithium hydroxide (2.91 g, 121 mmol) was slowly added dropwise at room temperature, and the mixture was stirred for 24 hours while maintaining the temperature. The reaction solution was cooled to 5°C, 1N-HCl solution was slowly added until the pH reached 4, poured into water, extracted with diethyl ether (300 mL), and washed twice with water. The organic phase was concentrated and the residue was separated and purified by silica gel column chromatography (developing solvent: toluene/ethyl acetate = 2/1) to obtain compound (105) (8.50 g, 28.9 mmol) as white crystals.

(Stage 4) Synthesis of Compound (K101) A solution of phenol derivative (106) (7.37 g, 29.9 mmol) in dichloromethane (5 mL) was cooled to -10°C under nitrogen atmosphere, and N,N'-dicyclohexylcarbodiimide (6.17 g, 29.9 mmol), 4-dimethylaminopyridine (1.00 g, 8.15 mmol), and the carboxylic acid derivative (105) obtained in the previous stage (4.00 g, 13.6 mmol) were added, and stirred at room temperature for 5 hours. The reaction solution was filtered, poured into water, and dichloromethane (50 mL) was added, and washed twice with sodium bicarbonate solution and twice with water. Then, after the organic phase was concentrated, the residue was separated and purified by silica gel column chromatography (developing solvent: toluene) to obtain compound (K101) (6.30 g, 8.39 mmol). The melting point of this compound is 85°C. ¹ H-NMR (CDCl ₃ , ppm): δ0.932-0.985 (6H, t), 1.37-1.43 (8H, m), 1.66-1.71 (4H, m), 2.66-2.69 (4H, t), 3.93 (2H, s), 5.07 (2H, s), 7.04-7.07 (4H, d), 7.24-7.31 (8H, m), 7.46-7.51 (8H, m), 7.58-7.60 (4H, d).

[Example 2] <Synthesis of Compound (K102)> [Chemical 47] (Compound (K1-1), Rodk1 = Rod1-1G, nk1 = nk2 = 0, R ^k2 = C ₅ H ₁₁ ) By the same method as in Example 1, using the following compound (107) instead of compound (106), compound (K102) (2.40 g, 2.66 mmol) was obtained. The melting point of this compound is 182°C. [Chemical 48] ¹ H-NMR (CDCl ₃ , ppm): δ0.885-0.914 (6H, t), 1.02-1.10 (4H, m), 1.20-1.35 (18H, m), 1.45-1.55 (4H, m), 1.86-1.93 (8H, m), 2.47-2.58 (2H, tt), 3.88 (2H, s), 5.03 (2H, s), 7.00-7.02 (4H, d), 7.21-7.22 (4H, m), 7.26-7.28 (4H, d), 7.42-7.48 (8H, m), 7.53-7.55 (4H, d).

[Example 3] <Synthesis of Compound (K103)> [Chemical 49] (Compound (K1-1), Rodk1 = Rod1-1D, nk1 = nk2 = 0, R ^k2 = C ₅ H ₁₁ ) By the same method as in Example 1, using the following compound (108) instead of compound (106), compound (K103) (9.04 g, 12.0 mmol) was obtained. The compound is amorphous at room temperature. [Chemical 50] ¹ H-NMR (CDCl ₃ , ppm): δ0.879-0.907 (6H, t), 0.990-1.06 (4H, m), 1.18-1.33 (18H, m), 1.38-1.43 (4H, m), 1.84-1.86 (8H, d), 2.40-2.48 (2H, tt), 3.82 (2H, s), 4.98 (2H, s), 6.84-6.86 (4H, d), 7.16-7.20 (8H, m), 7.38-7.40 (2H, d), 7.42-7.43 (2H, m).

[Example 4-1] The liquid crystal composition NLC-A was prepared by mixing the liquid crystal compounds shown in the figure below in the following proportions.

[Chemistry 51] [Chemistry 52]

The phase transition temperature (°C) of the liquid crystal composition NLC-A is N 79.7 I, and the average refractive index <n> is 1.56.

In the liquid crystal composition NLC-A (98.0 wt %), the compound (K101) (2.00 wt %) obtained in Example 1 was heated and dissolved at 100°C to obtain a liquid crystal composition CLC-A1. The phase transition temperature (°C) of the liquid crystal composition CLC-A1 was N* 79.1 I. At this time, the heating time required to obtain the completely dissolved liquid crystal composition CLC-A1 was 2 minutes. As a result, it was found that the compound (K101) showed very high solubility. The selective reflection wavelength (λ) of the liquid crystal composition CLC-A1 was 484.0 (nm), and the HTP of the compound (K101) calculated based on these values was 161 (μm ^-1 ). In addition, the VHR of the liquid crystal composition CLC-A1 was measured and the result was 96.1%. The results show that composition CLC-A1 exhibits a high voltage retention ratio.

[Example 4-2] A liquid crystal composition NLC-B was prepared by mixing the liquid crystal compounds shown in the figure below in the following proportions. [Chemical 53] [Chemistry 54]

The phase transition temperature (°C) of the liquid crystal composition NLC-B is N 87.9 I, and the average refractive index <n> is 1.56.

In the liquid crystal composition NLC-B (95.2 wt%), the compound (K101) (4.80 wt%) obtained in Example 1 was completely dissolved by heating and stirring at 100°C for 2 minutes to obtain a liquid crystal composition CLC-B1. The phase transition temperature (°C) of the liquid crystal composition CLC-B1 is N* 79.1 BP 79.2 I.

[Example 4-3] Preparation of monomer/liquid crystal mixture A liquid crystal composition MLC-B1 was prepared by mixing 89.2% by weight of the liquid crystal composition CLC-B1, 5.4% by weight of n-hexadecyl acrylate (C16A), 5.4% by weight of the compound (MC3-12), and 0.4% by weight of 2,2'-dimethoxyphenylacetophenone as a photopolymerization initiator as a mixture of the liquid crystal composition and the polymerizable monomer. The phase transition temperatures (°C) of the liquid crystal composition MLC-B1 were N* 51.1 BP 54.6 I, I 53.3 BP 49.7 N*.

[Chemistry 55]

[Example 4-4] Preparation of polymer/liquid crystal composite material The liquid crystal composition MLC-B1 was sandwiched between a comb-type electrode substrate that was not subjected to an alignment treatment and an opposing glass substrate (without an electrode) (cell thickness of 8 μm), and the obtained cell was heated to a blue phase of 52.0°C. In this state, ultraviolet light (ultraviolet light intensity of 23 mWcm ^-2 (365 nm)) was irradiated for 1 minute to perform a polymerization reaction. The polymer/liquid crystal composite material PSBP-B1 obtained in this way maintained an optically isotropic liquid crystal phase even when cooled to room temperature. Furthermore, as shown in Fig. 1, regarding the electrodes of the comb-type electrode substrate, the electrode 1 extending from the left side of the connecting electrode portion to the right and the electrode 2 extending from the right side of the connecting electrode portion to the left are arranged alternately. Therefore, in the case where there is a potential difference between the electrode 1 and the electrode 2, on the comb-type electrode substrate as shown in Fig. 1, if one electrode is focused on, the state of the electric field in the two directions of the upper direction and the lower direction in the figure can be provided.

[Example 4-5] The cell sandwiching the polymer/liquid crystal composite material PSBP-B1 obtained in Example 4-4 was set in the optical system shown in FIG2, and the electro-optical characteristics were measured. The optical system shown in FIG2 includes a light source 3, a polarizer 4, a comb electrode 5, an analyzer 6, and a photodetector 7. A white light source using a polarizing microscope (Eclipse LV100POL manufactured by Nikon) was used as the light source 3, and the cell was set in the optical system so that the incident angle toward the cell was perpendicular to the cell surface, and the line direction of the comb electrode 5 was 45° relative to the polarizer 4 and the analyzer 6 polarizers, respectively. The relationship between the applied voltage and the transmittance was investigated at room temperature. When a 68.4 V rectangular wave is applied, the transmittance is 89.7%, and the transmitted light intensity is saturated. The contrast is 1614, showing a very high value.

[Example 5-1] In the liquid crystal composition NLC-A (98.0 wt %), the compound (K102) (2.00 wt %) obtained in Example 2 was heated and dissolved at 100°C to obtain a liquid crystal composition CLC-A2. The phase transition temperature (°C) of the liquid crystal composition CLC-A2 is N* 79.1 I. At this time, the heating time required to obtain a completely dissolved liquid crystal composition CLC-A2 is 3 minutes. The results show that the compound (K102) shows very high solubility. The selective reflection wavelength (λ) of the liquid crystal composition CLC-A2 is 560 (nm). The HTP of the compound (K102) calculated based on these values is 139 (μm ^-1 ). In addition, the VHR of the liquid crystal composition CLC-A2 was measured and the result was 95.6%. The results show that composition CLC-A2 exhibits a high voltage retention ratio.

[Example 5-2] In the liquid crystal composition NLC-B (95.2 wt%), the compound (K102) (4.80 wt%) obtained in Example 2 was completely dissolved by heating and stirring at 100°C for 2 minutes to obtain a liquid crystal composition CLC-B2. The phase transition temperature (°C) of the liquid crystal composition CLC-B2 is N* 83.5 BP 83.7 I.

[Example 5-3] Preparation of monomer/liquid crystal mixture A liquid crystal composition MLC-B2 was prepared by mixing 89.2% by weight of the liquid crystal composition CLC-B2, 5.4% by weight of n-hexadecyl acrylate (C16A), 5.4% by weight of the compound (MC3-12), and 0.4% by weight of 2,2'-dimethoxyphenylacetophenone as a photopolymerization initiator as a mixture of the liquid crystal composition and the polymerizable monomer. The phase transition temperature (°C) of the liquid crystal composition MLC-B2 was N* 55.4 BP 55.5 I, I 55.6 BP 54.7 N*.

[Example 5-4] Preparation of polymer/liquid crystal composite material The liquid crystal composition MLC-B2 was sandwiched between a comb-type electrode substrate that was not subjected to an alignment treatment and an opposing glass substrate (without an electrode) (cell thickness of 8 μm), and the obtained cell was heated to a blue phase of 55.4°C. In this state, ultraviolet light (ultraviolet light intensity of 23 mWcm ^-2 (365 nm)) was irradiated for 1 minute to perform a polymerization reaction. The polymer/liquid crystal composite material PSBP-B2 obtained in this way maintained an optically isotropic liquid crystal phase even when cooled to room temperature.

[Example 5-5] The cell sandwiching the polymer/liquid crystal composite material PSBP-B2 obtained in Example 5-4 was set in the optical system shown in FIG. 2 to measure the electro-optical properties. A white light source using a polarizing microscope (Eclipse LV100POL manufactured by Nikon) was used as the light source 3, and the cell was set in the optical system so that the incident angle toward the cell was perpendicular to the cell surface and the line direction of the comb electrode 5 was 45° with respect to the polarizer 4 and the analyzer 6 polarizer, respectively. The relationship between the applied voltage and the transmittance was investigated at room temperature. When a rectangular wave of 59.5 V was applied, the transmittance was 88.9%, and the transmitted light intensity was saturated. The contrast was 1656, which showed a very high value.

[Example 6-1] The liquid crystal composition NLC-C is prepared by mixing the liquid crystal compounds shown in the figure below in the following proportions.

[Chemistry 56]

The phase transition temperature (°C) of the liquid crystal composition NLC-C is N 79.9 I, and the average refractive index <n> is 1.60.

In the liquid crystal composition NLC-C (95.8 wt%), the compound (K101) (4.2 wt%) obtained in Example 1 was completely dissolved by heating and stirring at 100°C for 2 minutes to obtain a liquid crystal composition CLC-C1. The phase transition temperature (°C) of the liquid crystal composition CLC-C1 is N* 75.9 I. In addition, the helical pitch of the liquid crystal composition CLC-C1 is 0.29 μm and the VHR is 99.1%. As a result, it can be seen that the composition CLC-C1 shows a high voltage retention rate.

[Example 6-2] Preparation of monomer/liquid crystal mixture A liquid crystal composition MLC-C1 was prepared by mixing the compound (K101) (0.9 wt %) obtained in Example 1, 5.90 wt % of the compound (MC2-04), and 0.3 wt % of 2,2'-dimethoxyphenylacetophenone as a photopolymerization initiator with the liquid crystal composition NLC-C (92.9 wt %). [Chemical 57]

[Example 6-3] Preparation of polymer/liquid crystal composite material The liquid crystal composition MLC-C1 was sandwiched between two glass substrates with electrodes provided with transparent conductive films that had not been subjected to alignment treatment (cell thickness was 10 μm), and the obtained cell was heated until MLC-04 became an isotropic phase. In this state, ultraviolet light (ultraviolet light intensity was 18 mWcm ^-2 (365 nm)) was irradiated for 1 minute to perform a polymerization reaction. The polymer/liquid crystal composite material PDLC-C1 obtained in this way maintained a chiral nematic phase even when cooled to room temperature.

[Example 6-4] The cell sandwiching the polymer/liquid crystal composite material PDLC-C1 obtained in Example 6-3 was set in an optical system to measure the electro-optical properties. A white light source using a polarizing microscope (Eclipse LV100POL manufactured by Nikon) was set in the optical system so that the incident angle toward the cell was perpendicular to the cell surface. The relationship between the applied voltage and the transmittance was investigated at room temperature. When a voltage of 20 V was applied, it was confirmed that the polymer/liquid crystal composite material PDLC-C1 was driven in the normal mode. When a voltage of 10 V is applied between the electrodes of the polymer/liquid crystal composite material PDLC-C1, the transmitted light intensity is 96.9%, and when a voltage of 22 V is applied, the transmitted light intensity is 10.0%, and a liquid crystal device with low voltage drive and high contrast can be obtained.

[Example 7-1] In the liquid crystal composition NLC-C (95.8 wt%), the compound (K102) (4.2 wt%) obtained in Example 2 was completely dissolved by heating and stirring at 100°C for 3 minutes to obtain a liquid crystal composition CLC-C2. The phase transition temperature (°C) of the liquid crystal composition CLC-C2 was N* 82.5 I. In addition, the helical pitch of the liquid crystal composition CLC-C2 was 0.33 μm and the VHR was 99.2%. As a result, it can be seen that the composition CLC-C2 showed a high voltage retention rate.

[Example 7-2] Preparation of monomer/liquid crystal mixture A liquid crystal composition MLC-C2 was prepared by mixing the compound (K102) (0.9 wt %) obtained in Example 2, 5.90 wt % of the compound (MC2-04), and 0.3 wt % of 2,2'-dimethoxyphenylacetophenone as a photopolymerization initiator with the liquid crystal composition NLC-C (92.9 wt %).

[Example 7-3] Preparation of polymer/liquid crystal composite material The liquid crystal composition MLC-C2 was sandwiched between two glass substrates with electrodes provided with transparent conductive films that had not been subjected to alignment treatment (cell thickness was 10 μm), and the obtained cell was heated until MLC-04 became an isotropic phase. In this state, ultraviolet light (ultraviolet light intensity was 18 mWcm ^-2 (365 nm)) was irradiated for 1 minute to perform a polymerization reaction. The polymer/liquid crystal composite material PDLC-C2 obtained in this way maintained a chiral nematic phase even when cooled to room temperature.

[Example 7-4] The cell sandwiching the polymer/liquid crystal composite material PDLC-C2 obtained in Example 7-3 was set in an optical system to measure the electro-optical properties. A white light source using a polarizing microscope (Eclipse LV100POL manufactured by Nikon) was set in the optical system so that the incident angle toward the cell was perpendicular to the cell surface. The relationship between the applied voltage and the transmittance was investigated at room temperature. When a voltage of 20 V was applied, it was confirmed that the polymer/liquid crystal composite material PDLC-C2 was driven in the normal mode. When a voltage of 10 V is applied between the electrodes of the polymer/liquid crystal composite material PDLC-C2, the transmitted light intensity is 91.1%, and when a voltage of 18 V is applied, the transmitted light intensity is 10.0%, and a liquid crystal device with low voltage drive and high contrast can be obtained.

[Example 8-1] In the liquid crystal composition NLC-C (95.8 wt%), the compound (K103) (4.2 wt%) obtained in Example 3 was completely dissolved by heating and stirring at 100°C for 2 minutes to obtain a liquid crystal composition CLC-C3. The phase transition temperature (°C) of the liquid crystal composition CLC-C3 is N* 75.4 I. In addition, the helical pitch of the liquid crystal composition CLC-C3 is 0.31 μm, and the VHR is 98.0%. As a result, it can be seen that the composition CLC-C3 shows a high voltage retention rate.

[Example 8-2] Preparation of monomer/liquid crystal mixture A liquid crystal composition MLC-C3 was prepared by mixing the compound (K103) (0.9 wt %) obtained in Example 3, 5.90 wt % of the compound (MC2-04), and 0.3 wt % of 2,2'-dimethoxyphenylacetophenone as a photopolymerization initiator with the liquid crystal composition NLC-C (92.9 wt %).

[Example 8-3] Preparation of polymer/liquid crystal composite material The liquid crystal composition MLC-C3 was sandwiched between two glass substrates with electrodes provided with transparent conductive films that had not been subjected to alignment treatment (cell thickness was 10 μm), and the obtained cell was heated until MLC-04 became an isotropic phase. In this state, ultraviolet light (ultraviolet light intensity was 18 mWcm ^-2 (365 nm)) was irradiated for 1 minute to perform a polymerization reaction. The polymer/liquid crystal composite material PDLC-C3 obtained in this way maintained a chiral nematic phase even when cooled to room temperature.

[Example 8-4] The cell sandwiching the polymer/liquid crystal composite material PDLC-C3 obtained in Example 8-3 was set in an optical system to measure the electro-optical properties. A white light source using a polarizing microscope (Eclipse LV100POL manufactured by Nikon) was used as a light source, and the cell was set in the optical system in such a way that the incident angle toward the cell was perpendicular to the cell surface. The relationship between the applied voltage and the transmittance was investigated at room temperature. When a voltage of 20 V was applied, it was confirmed that the polymer/liquid crystal composite material PDLC-C3 was driven in the normal mode. When a voltage of 10 V is applied between the electrodes of the polymer/liquid crystal composite material PDLC-C3, the light intensity transmitted is 91.0%, and when a voltage of 20 V is applied, the light intensity transmitted is 10.0%, and a liquid crystal device with a high contrast ratio that can be driven by a low voltage can be obtained. [Industrial Applicability]

Examples of effective uses of the present invention include liquid crystal elements such as display elements using polymer/liquid crystal composite materials, and dimming glass.

1. Electrode 1 2. Electrode 2 3. Light source 4. Polarizer 5. Comb electrode 6. Analyzer 7. Light receiver 10. Dimming layer 12. Liquid crystal compound 14. Polymer 20. Substrate

FIG1 shows a comb-shaped electrode substrate used in the embodiment. FIG2 shows an optical system used in the embodiment. FIG3(a) and FIG3(b) are cross-sections showing an example of the structure of a liquid crystal element. FIG4(a) and FIG4(b) are cross-sections showing another example of the structure of a liquid crystal element.

Claims (18)

A liquid crystal composition comprising at least one chiral compound represented by formula (K1) as a chiral component (K), and at least one achiral compound represented by formula (1-A) and formula (1-B) as a achiral component (T), wherein the content of the chiral component (K) in the liquid crystal composition is 0.1 wt% to 20 wt%, and the content of the achiral component (T) in the liquid crystal composition is 80 wt% to 99.9 wt%. Chiral component (K)

In formula (K1), R ^k1 is independently fluorine, chlorine, -C≡N, an alkyl group having 1 to 10 carbon atoms, or an alkenyl group having 2 to 10 carbon atoms, in which at least one -CH ₂ - may be substituted by -O-, but two consecutive -CH ₂ - groups may not be substituted by -O-, and in these groups, at least one hydrogen group may be substituted by a halogen; Y ^k1 is independently a single bond or -(CH ₂ ) _n -, where n is an integer of 1 to 20; nk1 and nk2 are independently an integer of 0 to 4; Rod ^k1 is a partial structural formula (Rod1), in which R ^k2 is an alkyl group having 1 to 6 carbon atoms or an alkenyl group having 2 to 7 carbon atoms; Ring A ^k1 , Ring A ^k2 , and Ring A ^k3 is independently 1,4-cyclohexylene, 1,4-phenylene, 1,4-phenylene in which at least one hydrogen atom is substituted with fluorine, 1,3-dioxane-2,5-diyl, tetrahydropyran-2,5-diyl, or pyrimidine-2,5-diyl; Z ^k1 , Z ^k2 , and Z ^k3 are independently a single bond, -CH ₂ CH ₂ -, -COO-, -OCO-, -OCH ₂ -, -CH ₂ O-, -CF ₂ O-, -OCF ₂ -, -CH=CH-, -CF ₂ CF ₂ -, -CF=CF-, or -C≡C-; mk1 and mk2 are independently an integer of 0 or 1; and 0 to 4 R are linked to the ring structure shown below. In the partial structure (X1) and the partial structure (X2) of ^k1 , 0 to 4 hydrogen atoms in the hydrogen atoms forming the ring structure may be replaced by R ^k1 .

． Non-chiral component (T)

In formula (1-A) and formula (1-B), R ¹¹ and R ¹² are independently hydrogen, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, or an alkenyl group having 2 to 10 carbon atoms, in which at least one -CH ₂ - may be substituted by -O-, but two consecutive -CH ₂ - groups may not be substituted by -O-, and in these groups, at least one hydrogen may be substituted by a halogen; Ring A ¹¹ , Ring A ¹² , and Ring A ¹³ are independently 1,4-cyclohexylene, 1,4-phenylene, 1,4-phenylene in which at least one hydrogen is substituted by fluorine, 1,3-dioxane-2,5-diyl, tetrahydropyran-2,5-diyl, or pyrimidine-2,5-diyl; Z ¹¹ , Z ¹² , and Z ¹³ are independently a single bond, -CH ₂ CH ₂ -, -COO-, -OCO-, -CH ₂ O-, -OCH ₂ -, -CF ₂ O-, -OCF ₂ -, -CH=CH-, -CF=CF-, or -C≡C-; X ¹¹ is fluorine, chlorine, -SF ₅ , -CHF ₂ , -CF ₃ , -CF ₂ CH ₂ F, -CF ₂ CHF ₂ , -CF ₂ CF ₃ , -(CF ₂ ) ₃ -F, -CF ₂ CHFCF ₃ , -CHFCF ₂ CF ₃ , -(CF ₂ ) ₄ -F, -(CF ₂ ) ₅ -F, -OCHF ₂ , -OCF ₃ , -OCF ₂ CH ₂ F, -OCF ₂ CHF ₂ , -OCH ₂ CF ₃ , -OCF ₂ CF ₃ , -O-(CF ₂ ) ₃ -F, -OCF ₂ CHFCF ₃ , -OCHFCF ₂ CF ₃ , -O-(CF ₂ ) ₄ -F, -O-(CF ₂ ) ₅ -F, -CH=CF ₂ , -CH=CHCF ₃ , or -CH=CHCF ₂ CF ₃ ; L ¹¹ and L ¹² are independently hydrogen or fluorine; L ¹³ and L ¹⁴ are independently hydrogen, fluorine, chlorine, or -C≡N, but L ¹³ and L ¹⁴ are not both hydrogen; S ¹¹ is hydrogen or methyl; m and n are independently 0 or 1. The liquid crystal composition as described in item 1 of the patent application, wherein the chiral compound represented by formula (K1) is a chiral compound represented by formula (K1-1),

In formula (K1-1), R ^k1 is independently fluorine, chlorine, -C≡N, an alkyl group having 1 to 10 carbon atoms, or an alkenyl group having 2 to 10 carbon atoms, in which at least one -CH ₂ - may be substituted by -O-, but two consecutive -CH ₂ - groups may not be substituted by -O-, and in these groups, at least one hydrogen may be substituted by a halogen; nk1 and nk2 are independently integers of 0 to 4, Rod ^k1 is the partial structural formula (Rod1-1) or the partial structural formula (Rod1-2), in which R ^k2 is an alkyl group having 1 to 6 carbon atoms or an alkenyl group having 2 to 7 carbon atoms; Ring A ^k1 , Ring A ^k2 , and Ring A ^k3 is independently 1,4-cyclohexylene, 1,4-phenylene, 1,4-phenylene in which at least one hydrogen atom is substituted with fluorine, 1,3-dioxane-2,5-diyl, tetrahydropyran-2,5-diyl, or pyrimidine-2,5-diyl; Z ^k2 and Z ^k3 are independently a single bond, -CH ₂ CH ₂ -, -COO-, -OCO-, -OCH ₂ -, -CH ₂ O-, -CF ₂ O-, -OCF ₂ -, -CH=CH-, -CF ₂ CF ₂ -, -CF=CF-, or -C≡C-; mk1 and mk2 are independently an integer of 0 or 1; and R is linked to the ring structure shown below. In the partial structure (X1) and the partial structure (X2) of ^k1 , 0 to 4 hydrogen atoms in the hydrogen atoms forming the ring structure may be replaced by R ^k1 )

The liquid crystal composition as described in claim 2, wherein in formula (K1-1), R ^k1 is independently an alkyl group having 1 to 10 carbon atoms or an alkenyl group having 2 to 10 carbon atoms, in the alkyl group, at least one -CH ₂ - may be substituted by -O-, but two consecutive -CH ₂ - groups may not be substituted by -O-, and in these groups, at least one hydrogen may be substituted by a halogen; nk1 and nk2 are independently integers of 0 to 4, and Rod ^k1 is any one of the partial structural formulas (Rod1-1A) to (Rod1-1H) and the partial structural formulas (Rod1-2A) to (Rod1-2H) shown below,

In the partial structural formulas (Rod1-1A) to (Rod1-1H) and the partial structural formulas (Rod1-2A) to (Rod1-2H), R ^k2 is an alkyl group having 1 to 6 carbon atoms or an alkenyl group having 2 to 7 carbon atoms; in addition, the partial structure (X3) shown below in which (F) is linked to a 1,4-phenylene group represents a 1,4-phenylene group in which one or two hydrogen atoms may be substituted with fluorine atoms,

A liquid crystal composition as described in any one of items 1 to 3 of the patent application, wherein the achiral compound represented by formula (1-A) is any one of the achiral compounds represented by formula (1-A-01) to formula (1-A-22),

In formula (1-A-01) to formula (1-A-22), R ¹¹ is independently an alkyl group having 1 to 10 carbon atoms or an alkenyl group having 2 to 10 carbon atoms, at least one -CH ₂ - in the alkyl group and the alkenyl group may be substituted by -O-, but two consecutive -CH ₂ - groups may not be substituted by -O-; Ring A ¹¹ and Ring A ¹² are independently 1,4-cyclohexylene, tetrahydropyran-2,5-diyl, or pyrimidine-2,5-diyl; X ¹¹ is independently fluorine, chlorine, -CF ₃ , or -OCF ₃ ; (F) is hydrogen or fluorine. A liquid crystal composition as described in any one of items 1 to 3 of the patent application, wherein the achiral compound represented by formula (1-B) is any one of the achiral compounds represented by formula (1-B-01) to formula (1-B-22),

In formula (1-B-01) to formula (1-B-22), R ¹¹ and R ¹² are independently alkyl having 1 to 10 carbon atoms or alkenyl having 2 to 10 carbon atoms, at least one -CH ₂ - in the alkyl and alkenyl groups may be substituted by -O-, but two consecutive -CH ₂ - groups may not be substituted by -O-; Ring A ¹¹ and Ring A ¹² are independently 1,4-cyclohexylene, tetrahydropyran-2,5-diyl, or pyrimidine-2,5-diyl; and (F) is hydrogen or fluorine. A liquid crystal composition as described in any one of items 1 to 3 of the patent application scope, wherein the content of the compound represented by formula (1-A) or formula (1-B) in the non-chiral component (T) is 50% by weight to 100% by weight. A liquid crystal composition as described in any one of items 1 to 3 of the patent application, wherein the content of the compound represented by formula (1-A) in the non-chiral component (T) is 50% by weight to 100% by weight, and exhibits an optically isotropic liquid crystal phase. A liquid crystal composition as described in any one of items 1 to 3 of the patent application, wherein the chiral component (K) further contains at least one chiral compound represented by formula (K2) to formula (K8),

In formula (K2) to formula (K8), R ^K is independently hydrogen, halogen, -C≡N, -N=C=O, -N=C=S or an alkyl group having 1 to 20 carbon atoms, at least one -CH ₂ - in the alkyl group may be substituted by -O-, -S-, -COO-, -OCO-, -CH=CH-, -CF=CF- or -C≡C-, at least one hydrogen in the alkyl group may be substituted by a halogen; A ^K is independently an aromatic 6- to 8-membered ring, a non-aromatic 3- to 8-membered ring, or a condensed ring having 9 to 20 carbon atoms, at least one hydrogen in the ring may be substituted by a halogen, an alkyl group having 1 to 3 carbon atoms or a halogenated alkyl group, the -CH ₂ - may be substituted by -O-, -S- or -NH-, -CH= may be substituted by -N=; Y ^K are independently hydrogen, halogen, alkyl with 1 to 3 carbon atoms, halogenated alkyl with 1 to 3 carbon atoms, aromatic 6- to 8-membered ring, non-aromatic 3- to 8-membered ring, or condensed ring with 9 to 20 carbon atoms, at least one hydrogen of these rings may be substituted by halogen, alkyl with 1 to 3 carbon atoms or halogenated alkyl, -CH ₂ - may be substituted by -O-, -S- or -NH-, -CH= may be substituted by -N=; Z ^K are independently single bond, or alkylene with 1 to 8 carbon atoms, but at least one -CH ₂ - may be substituted by -O-, -S-, -COO-, -OCO-, -CSO-, -OCS-, -N=N-, -CH=N-, -N=CH-, -CH=CH-, -CF=CF- or -C≡C-, and at least one hydrogen may be substituted by a halogen; X ^K are independently a single bond, -COO-, -OCO-, -CH ₂ O-, -OCH ₂ -, -CF ₂ O-, -OCF ₂ - or -CH ₂ CH ₂ -; mK are independently an integer of 1 to 4. A monomer/liquid crystal mixture, comprising a liquid crystal composition as described in any one of items 1 to 8 of the patent application scope, and a polymerizable monomer. The monomer/liquid crystal mixture described in item 9 of the patent application shows a chiral nematic phase in a temperature range of at least 1°C from -20°C to 70°C, and the helical pitch is less than 700nm in at least a part of the temperature range. The monomer/liquid crystal mixture as described in item 9 of the patent application scope, wherein the liquid crystal composition is a liquid crystal composition having an optically isotropic liquid crystal phase. A monomer/liquid crystal mixture as described in any one of items 9 to 11 of the patent application scope, wherein the content of the polymerizable monomer is in the range of 0.1 wt% to 50 wt% relative to the total amount of the monomer/liquid crystal mixture. A polymer/liquid crystal composite material is obtained by polymerizing the monomer/liquid crystal mixture as described in item 9 of the patent application scope in a non-liquid crystal isotropic phase or an optically isotropic liquid crystal phase, and is used for a liquid crystal element driven by an optically isotropic liquid crystal phase. A polymer/liquid crystal composite material is obtained by polymerizing the monomer/liquid crystal mixture as described in item 9 of the patent application scope, and is used for a light scattering liquid crystal element driven by a chiral nematic phase. A liquid crystal element, comprising: a pair of substrates having electrodes; a dimming layer sandwiched between the pair of substrates; and an electric field applying component for applying an electric field to the dimming layer via the electrodes, at least one of the pair of substrates is transparent, and the dimming layer comprises a polymer/liquid crystal composite material as described in item 13 or 14 of the patent application scope. The liquid crystal element as described in item 15 of the patent application, wherein the polymer/liquid crystal composite material exhibits a chiral nematic phase and constitutes a light scattering liquid crystal element. The liquid crystal element as described in item 15 or 16 of the patent application, wherein the content of the polymer in the polymer/liquid crystal composite material is in the range of 0.1 wt% to 50 wt%. A chiral compound represented by the following formula (K101), formula (K102), or formula (K103),

Here, (R) indicates chirality.