JP2008106107A - Light-modulating material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light-modulating material by a guest host method excellent in light modulation, heat resistance and moist heat durability. <P>SOLUTION: This light-modulating material is provided by equipping a liquid crystal layer containing a dichroic pigment expressed by general formula (1) [wherein, R<SP>1</SP>to R<SP>8</SP>are each independently H or a substituent, but at least one of the R<SP>2</SP>, R<SP>3</SP>, R<SP>6</SP>and R<SP>7</SP>is a substituent expressed by -(Het)<SB>m</SB>-ä(B<SP>1</SP>)<SB>p</SB>-(Q<SP>1</SP>)<SB>q</SB>-(B<SP>2</SP>)<SB>r</SB>}<SB>n</SB>-C<SP>1</SP>; Het is O, S or NR; R is H, an alkyl, an aryl or a heteroaryl; B<SP>1</SP>, B<SP>2</SP>are each independently a divalent aryl, a heteroaryl or a cyclic aliphatic hydrocarbon group; Q<SP>1</SP>is a divalent linking group; C<SP>1</SP>is an alkyl, a cycloalkyl, an alkoxy, an acyl, an alkoxycarbonyl or an acyloxy; (m) is 0 or 1; (p), (q), (r) are each any of 0 to 5 integer; and (n) is any of 1 to 3 integer, but (p+r)×(n) is 3 to 10.] and a host liquid crystal, and transmitts incident light. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a light control material, and particularly belongs to the technical field of guest-host light control materials.

  With the increasing interest in the environment, the importance of materials capable of electrically adjusting the amount of light, so-called electrical light control materials, is increasing. Such light control materials are expected to have a wide range of applications such as interior use, building material use, vehicle use, and advertisement use. Until now, electrochromic methods using an oxidation-reduction reaction, polymer dispersed liquid crystal (PDLC) methods using a composite system of a liquid crystal and a polymer, and the like have been proposed as electrical light control materials. However, it is difficult to increase the area by current drive in the electrochromic method, and there are problems such as problems in the durability of the electrochromic dye. In the PDLC method, there is only switching between scattered white and transparent state. Since this is not possible, the application is limited, and the drive voltage may be high, and improvements have been demanded.

The light control material using the guest host system can be brightly controlled, and is expected as a system suitable for light control applications. However, what has been proposed so far (see, for example, Patent Document 1) may not be at a satisfactory level of dimming performance, and improvements have been demanded. Further, the conventional guest-host system may have a problem from the viewpoint of durability, and an improvement thereof has been demanded. In particular, when used outdoors or as a vehicle application, durability is an important performance, and a light-durable material with higher durability has been demanded.
JP 2000-347224 A

  The objective of this invention is providing the light control material by the guest host system excellent in light resistance, heat resistance, and thermal-humidity durability.

  In view of the above situation, the present inventor has conducted extensive research and can realize a light-modulating material that provides extremely high durability by combining a dichroic dye having a specific substituent at a specific substitution position. The present invention was completed by further studying based on this knowledge.

Means for solving the above-mentioned problems are as follows.
<1> A liquid crystal layer containing at least one kind of dichroic dye represented by the following general formula (1) and at least one kind of host liquid crystal is provided between a pair of electrodes, and allows incident light to pass therethrough. It is a light control material characterized.

In the formula, R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ and R ⁸ each independently represent a hydrogen atom or a substituent, but R ² , R ³ , R ⁶ and R ⁷ at least one of represents _{- ^{{(B 2) r (B}} 1) p - - - (Q 1) q} substituent represented by n -C ^{1 (Het)} _m. Het represents an oxygen atom, a sulfur atom or NR, and R represents a hydrogen atom, an alkyl group, an aryl group or a heteroaryl group. B ¹ and B ² each independently represent a divalent aryl group, heteroaryl group or cyclic aliphatic hydrocarbon group, Q ¹ represents a divalent linking group, C ¹ represents an alkyl group, a cycloalkyl group, Represents an alkoxy group, an acyl group, an alkoxycarbonyl group or an acyloxy group; m represents 0 or 1, p, q and r each represent an integer of 0 to 5, n represents an integer of 1 to 3, but (p + r) × n is 3 to 10 is there. When p, q and r are each 2 or more, 2 or more B ¹ , Q ¹ and B ² may be the same or different. When n is 2 or more, 2 or more {(B ¹ ) _p − (Q ¹ ) _q- (B ² ) _r } may be the same or different.

<2> In the general formula (1), at least R ² is represented by-(Het) _m -{(B ¹ ) _p- (Q ¹ ) _q- (B ² ) _r } _n -C ^1. The light modulating material according to <1>, wherein the light modulating material is a substituent.

<3> In the general formula (1), any two of R ² , R ³ , R ⁶ and R ⁷ are the-(Het) _m -{(B ¹ ) _p- (Q ¹ ) _q- (B ²⁾ a light modulating material according to <1> or <2>, which is a substituent represented by _{r} n} -C ^1.

<4> In the general formula (1), R ² and R ⁶ are represented by-(Het) _m -{(B ¹ ) _p- (Q ¹ ) _q- (B ² ) _r } _n -C ^1. is a substituent that, or the ^{R 2} and _{^{R 3 - (Het) m -}} {(B 1) p - (Q 1) q - (B 2) r} substituent represented by n -C ¹ It is the light control material as described in said <3> characterized by the above-mentioned.

<5> In any one of the above items <1> to <4>, in the general formula (1), at least one of R ¹ , R ⁴ , R ⁵ , and R ⁸ is a hydroxy group. It is the light control material as described in above.

<6> The light control material according to <5>, wherein at least R ¹ in the general formula (1) is a hydroxy group.

<7> The light control material according to <6>, wherein R ¹ and R ^{5 in the} general formula (1) are hydroxy groups.

<8> In any one of the above items <1> to <7>, in the general formula (1), m = 0, p = 2, q = 0, r = 1, and n = 1. It is the light control material as described in above.

<9> The light control material according to any one of <1> to <8>, wherein the host liquid crystal includes a chiral agent.

<10> The light control material according to any one of <1> to <9>, wherein the host liquid crystal is a nematic liquid crystal.

<11> Any one of the above <1> to <10>, wherein the light is adjusted by changing between a colored state and a transparent state, or the light is changed by changing between a scattered colored state and a transparent state. It is the light control material as described in above.

<12> The light modulating material according to <11>, wherein a ratio of light transmittance in the colored state and the transparent state (transparent state / colored state) is in a range of 3 to 1000.

<13> The light modulating material according to any one of <1> to <12>, further including a polymer support.

<14> The light control material according to any one of <1> to <13>, further including an ultraviolet absorbing layer.

<15> The light control material according to any one of <1> to <14>, wherein the light control material is used outdoors.

  ADVANTAGE OF THE INVENTION According to this invention, the light control material by a guest host system excellent in light resistance, heat resistance, and heat humidity durability can be provided.

  Hereinafter, the present invention will be described in detail. In the present specification, “to” indicates a range including the numerical values described before and after the minimum and maximum values, respectively.

  The light modulating material of the present invention contains at least one dichroic dye represented by the following general formula (1) and at least one host liquid crystal.

In the formula, R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ and R ⁸ each represent a hydrogen atom or a substituent, but at least R ² , R ³ , R ⁶ and R ⁷ one represents _{- ^{{(B 2) r (B}} 1) p - - - (Q 1) q} substituent represented by n -C ^{1 (Het)} _m. Het represents an oxygen atom, a sulfur atom or NR, and R represents a hydrogen atom, an alkyl group, an aryl group or a heteroaryl group. B ¹ and B ² each represent a divalent aryl group, a heteroaryl group or a cyclic aliphatic hydrocarbon group, Q ¹ represents a divalent linking group, C ¹ represents an alkyl group, a cycloalkyl group, an alkoxy group, Represents an acyl group, an alkoxycarbonyl group or an acyloxy group. m represents 0 or 1, p, q and r each represent an integer of 0 to 5, n represents an integer of 1 to 3, but (p + r) × n is 3 to 10 is there. When p, q and r are each 2 or more, 2 or more B ¹ , Q ¹ and B ² may be the same or different. When n is 2 or more, 2 or more {(B ¹ ) _p − (Q ¹ ) _q- (B ² ) _r } may be the same or different. ) A dichroic dye and at least one kind of host liquid crystal are contained.

  For example, a light-control glass that arbitrarily adjusts the transmittance of light from a window is clearly colored or scattered and clouded under certain conditions, and extremely difficult under other conditions. It is desirable that the transparency is high.

  The light-modulating material of the present invention can be dimmed by changing the orientation state of the host liquid crystal to change between a transparent colored state and a transparent state, or can be dimmed by changing between a scattered colored state and a transparent state. Can be. In particular, since the chromic material of the present invention uses the dichroic dye represented by the general formula (1), the difference in light absorption between the colored state and the transparent state is good, and the alignment state of the host liquid crystal is supported. When it is horizontal with respect to the surface of the body, it shows high color development, and when the alignment state is vertical with respect to the surface of the support, it shows high light control performance such that the light transmittance is high. Furthermore, it has been found that the light control material of the present invention has an unexpected effect of high durability against light, heat, and moisture, and has been found to be suitable for outdoor use.

  In the case of a light-modulating material, an observer observes the state where light passes through the light-modulating material only once, whereas in the case of a liquid crystal display element, after light passes through the liquid crystal display element, Since the observer observes the state of being reflected and passing through the liquid crystal display element again, it is necessary to absorb light with the dichroic dye more efficiently than in the case of the liquid crystal display element in the case of the light control material, It is not clear whether high light control performance can be obtained when the composition of the liquid crystal display element is used as it is for the light control material.

  The light control material of the present invention comprises at least one liquid crystal layer containing at least the dichroic dye and the host liquid crystal. In the present specification, a composition constituting the liquid crystal layer is referred to as a “liquid crystal composition”, and the liquid crystal composition contains at least the dichroic dye and the host liquid crystal, Additives can also be included.

<Liquid crystal layer>
(Dichroic dye)
In the light control material of the present invention, the dichroic dye is defined as a compound that dissolves in the host liquid crystal and has a function of absorbing light. The dichroic dye of the present invention may have any absorption maximum and absorption band, but has an absorption maximum in the yellow region (Y), magenta region (M), or cyan region (C). The case is preferred. Two or more dichroic dyes may be used, and it is preferable to use a mixture of dichroic dyes having absorption maxima in Y, M, and C. A method for performing full color display by mixing a yellow dye, a magenta dye and a cyan dye is detailed in “Color Chemistry” (written by Sumio Tokita, Maruzen, 1982). Here, the yellow region is a range of 430 to 490 nm, the magenta region is a range of 500 to 580 nm, and the cyan region is a range of 600 to 700 nm.

In the present invention, the anthraquinone compound represented by the general formula (1) is used as the dichroic dye. When the dichroic dye has an anthraquinone skeleton, when it is used as a light control material, decomposition to light, heat and moisture is suppressed. Therefore, it exhibits excellent durability against light, heat and moisture. In particular, durability against light is improved.
Hereinafter, the dichroic dye represented by the general formula (1) will be described in detail.

In the general formula (1), R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ and R ⁸ each represent a hydrogen atom or a substituent, but R ² , R ³ , R ⁶ And at least one of R ⁷ represents a substituent represented by-(Het) _m -{(B ¹ ) _p- (Q ¹ ) _q- (B ² ) _r } _n -C ¹ .
Here, at least one of R ² , R ³ , R ⁶ and R ⁷ in the general formula (1) is-(Het) _m -{(B ¹ ) _p- (Q ¹ ) _q- (B ² ) _r }. _The reason why the durability against light, heat, and moisture is increased when the dichroic dye that is the substituent represented by _n- C ¹ is used in the light control material is as follows. It is not limited by the following action.

That is, at least one of R ² , R ³ , R ⁶ and R ⁷ is represented by-(Het) _m -{(B ¹ ) _p- (Q ¹ ) _q- (B ² ) _r } _n -C ^1. The dichroic dye, which is a substituent, exhibits a shape in which a rod-like substituent is introduced with respect to the molecular long axis, so that the degree of order in the host liquid crystal is high and the solubility in the host liquid crystal is high. It has the characteristics. Since the degree of order and solubility in the host liquid crystal are high, it is considered that the dye molecules are present in close compatibility with the host liquid crystal at the molecular level. For this reason, it is estimated that the penetration | invasion of oxygen and a water molecule is suppressed and it is hard to be decomposed | disassembled. As a result, it is estimated that durability against light, heat, and moisture is increased.

In particular, it is a host liquid crystal that at least R ² is a substituent represented by-(Het) _m -{(B ¹ ) _p- (Q ¹ ) _q- (B ² ) _r } _n -C ¹ It is preferable from the viewpoints of high degree of ordering and high solubility in the host liquid crystal.
Further, the compound represented by the general formula (1), wherein _{^{- (Het) m - {(}} B 1) p - (Q 1) q - (B 2) r} substituent represented by n -C ¹ May be any number, and is preferably a mono-substituted product having one, a di-substituted product having two, a tri-substituted product having three, a tetra-substituted product having four, and a di-substituted product or a tri-substituted product. The di-substituted product is more preferable because the order in the host liquid crystal is higher and the solubility in the host liquid crystal is higher.

In the case where the compound represented by the general formula (1) is a di-substituted product, it is a combination of R ² and R ⁶ and having the substituent has a higher degree of order in the host liquid crystal. From the viewpoint of increasing the solubility in the host liquid crystal, it is preferable that the substituent is a combination of R ² and R ³ .

  In the general formula (1), Het represents an oxygen atom, a sulfur atom or NR, and R represents a hydrogen atom, an alkyl group, an aryl group or a heteroaryl group. Het is preferably an oxygen atom or a sulfur atom, and particularly preferably a sulfur atom. As the alkyl group, aryl group or heteroaryl group represented by R, those exemplified in the above-mentioned Substituent group V can be mentioned. R preferably represents a hydrogen atom or an alkyl group, more preferably a hydrogen atom.

B ¹ and B ² each represent a divalent aryl group, a heteroaryl group, or a cyclic aliphatic hydrocarbon group. The divalent aryl group is preferably an aryl group having 2 to 20 carbon atoms. Specifically, divalent groups such as a benzene ring, a naphthalene ring, and an anthracene ring are preferable. Particularly preferred are divalent groups of a benzene ring and a substituted benzene ring, and more preferred is a 1,4-phenylene group. The divalent heteroaryl group represented by each of B ¹ and B ² is preferably a C 1-20 heteroaryl group. Specifically, pyridine ring, quinoline ring, isoquinoline ring, pyrimidine ring, pyrazine ring, thiophene ring, furan ring, oxazole ring, thiazole ring, imidazole ring, pyrazole ring, oxadiazole ring, thiadiazole ring, triazole ring, and A condensed divalent heteroaryl group formed by condensation of these is preferable. Preferred specific examples of the divalent cyclic aliphatic hydrocarbon group represented by each of B ¹ and B ² include a cyclohexane-1,2-diyl group, a cyclohexane-1,3-diyl group, and a cyclohexane-1,4-diyl group. And cyclopentane-1,3-diyl group, particularly preferably (E) -cyclohexane-1,4-diyl group.

Q ¹ represents a divalent linking group. Preferably, it represents a divalent linking group comprising an atomic group composed of an atom selected from a carbon atom, a nitrogen atom, a sulfur atom and an oxygen atom. Examples of the divalent linking group include alkylene groups having 1 to 20 carbon atoms (for example, methylene group, ethylene group, propylene group, butylene group, pentylene group, cyclohexyl-1,4-diyl group), and 2 to 20 carbon atoms. Alkenylene group (for example, ethenylene group), alkynylene group having 2 to 20 carbon atoms (for example, ethynylene group), amide group, ether group, ester group, sulfoamide group, sulfonate group, ureido group, sulfonyl group, sulfinyl group , A thioether group, a carbonyl group, an —NR— group (wherein R represents a hydrogen atom, an alkyl group or an aryl group), an azo group, an azoxy group, a heterocyclic divalent group (for example, piperazine-1,4-diyl) Group), or a divalent linking group having 0 to 60 carbon atoms constituted by combining two or more thereof. Q ¹ preferably represents a divalent linking group comprising an alkylene group, alkenylene group, alkynylene group, ether group, thioether group, amide group, ester group, carbonyl group, or a combination thereof.

C ¹ represents an alkyl group, a cycloalkyl group, an alkoxy group, an acyl group, an alkoxycarbonyl group or an acyloxy group. Preferable examples include alkyl and cycloalkyl groups having 1 to 30 carbon atoms, preferably 1 to 12 carbon atoms, and more preferably 1 to 8 carbon atoms (for example, methyl group, ethyl group, propyl group, butyl group, t-butyl group). Group, i-butyl group, s-butyl group, pentyl group, t-pentyl group, hexyl group, heptyl group, octyl group, cyclohexyl group, 4-methylcyclohexyl group, 4-ethylcyclohexyl group, 4-propylcyclohexyl group, 4-butylcyclohexyl group, 4-pentylcyclohexyl group, hydroxymethyl group, trifluoromethyl group, benzyl group); C1-C20, preferably C1-C10, more preferably C1-C8 alkoxy group (For example, methoxy group, ethoxy group, 2-methoxyethoxy group, 2-phenylethoxy group); 0, preferably 1-12 carbon atoms, more preferably 2-8 carbon acyl groups (eg acetyl, pivaloyl, formyl groups); 1-20 carbons, preferably 2-12 carbons, more preferably C2-C8 acyloxy group (for example, acetyloxy group, benzoyloxy group); C2-C20, preferably C2-C12, more preferably C2-C8 alkoxycarbonyl group (for example, methoxycarbonyl group) , An ethoxycarbonyl group, a 2-benzyloxycarbonyl group). C ¹ is particularly preferably an alkyl group or an alkoxy group, and more preferably an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group or a trifluoromethoxy group.

m represents 0 or 1, particularly preferably 0.
p, q, and r each represent an integer of 0 to 5, and n represents an integer of 1 to 3, but (p + r) × n satisfies 3 to 10. In addition, when p, q, r, and n are each 2 or more, the repeating unit may be the same or different. Preferred combinations of p, q, r and n are described below.
(1) p = 3, q = 0, r = 0, n = 1
(2) p = 4, q = 0, r = 0, n = 1
(3) p = 5, q = 0, r = 0, n = 1
(4) p = 2, q = 1, r = 1, n = 1
(5) p = 1, q = 1, r = 2, n = 1
(6) p = 3, q = 1, r = 1, n = 1
(7) p = 1, q = 1, r = 3, n = 1
(8) p = 2, q = 1, r = 2, n = 1
(9) p = 1, q = 1, r = 1, n = 3
(10) p = 0, q = 1, r = 3, n = 1
(11) p = 0, q = 1, r = 2, n = 2
(12) p = 1, q = 1, r = 2, n = 2
(13) p = 2, q = 1, r = 1, n = 2
(14) p = 2, q = 0, r = 1, n = 1
(15) p = 1, q = 0, r = 2, n = 1

  More preferably, (1) p = 3, q = 0, r = 0, n = 1; (2) p = 4, q = 0, r = 0, n = 1; (4) p = 2, q = 1, r = 1, n = 1; (14) p = 2, q = 0, r = 1, n = 1; (15) p = 1, q = 0, r = 2, n = 1 More preferably, (1) p = 3, q = 0, r = 0, n = 1; (14) p = 2, q = 0, r = 1, n = 1; (15) p = 1, q = 0, r = 2, n = 1, and particularly preferably (14) p = 2, q = 0, r = 1, n = 1; (15) p = 1, q = A combination of 0, r = 2, and n = 1. In the case of this combination, the solubility in the host liquid crystal becomes high, which is preferable from the viewpoint that a light control material with high display performance can be provided.

Note that-{(B ¹ ) _p- (Q ¹ ) _q- (B ² ) _r } _n -C ¹ preferably includes a structure exhibiting liquid crystallinity. The liquid crystal as used herein may be in any phase, but is preferably a nematic liquid crystal, a smectic liquid crystal, or a discotic liquid crystal. In particular, the driving voltage is low, the response speed is relatively fast, and the driving is performed in a wide temperature range. A nematic liquid crystal is preferable from the viewpoint that it can be formed. Specific examples of the liquid crystal compound include those described in Chapter 3 “Molecular Structure and Liquid Crystallinity” of 2000, Chapter 3 “Molecular Structure and Liquid Crystallinity” edited by the Committee for Editing the Liquid Crystal Handbook, Liquid Crystal Handbook.

Specific examples of-{(B ¹ ) _p- (Q ¹ ) _q- (B ² ) _r } _n -C ¹ are shown below, but the present invention is not limited to this (in the figure, wavy lines are Represents the connection position).

The preferable structure of the substituent represented by the-{(B ¹ ) _p- (Q ¹ ) _q- (B ² ) _r } _n -C ¹ is the following combination.
[1] B ¹ represents an aryl group or a heteroaryl group, B ² represents a cyclohexane-1,4-diyl group, C ¹ represents an alkyl group, p = 2, q = 0, r = 1 and n A structure representing = 1.
[2] B ¹ represents an aryl group or a heteroaryl group, B ² represents a cyclohexane-1,4-diyl group, C ¹ represents an alkyl group, p = 1, q = 0, r = 2 and n A structure representing = 1.

A particularly preferred structure is
[I] B ¹ represents a 1,4-phenylene group, B ² represents a trans-cyclohexyl group, and C ¹ represents an alkyl group (preferably a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, or a hexyl group). ), And a structure represented by the following general formula (a-1) wherein p = 2, q = 0, r = 1 and n = 1,
[2] B ¹ represents a 1,4-phenylene group, B ² represents a trans-cyclohexane-1,4-diyl group, and C ¹ represents an alkyl group (preferably a methyl group, an ethyl group, a propyl group, a butyl group). , A pentyl group or a hexyl group), and a structure represented by the following general formula (a-2) where p = 1, q = 0, r = 2 and n = 1.
In the structure represented by the general formula (a-1) or (a-2), the degree of order in the host liquid crystal is high and the solubility in the host liquid crystal is high. This is preferable from the viewpoint that a material can be provided.

In the general formulas (a-1) and (a-2), R ^{a1 to} R ^a12 each independently represent a hydrogen atom or a substituent. Examples of the substituent include a substituent selected from the aforementioned substituent group V.
R ^{a1 to} R ^a12 are preferably each independently a hydrogen atom, a halogen atom (particularly a fluorine atom), an alkyl group, an aryl group, or an alkoxy group. Among the alkyl groups, aryl groups, and alkoxy groups represented by R ^{a1 to} R ^a12 , preferable ones have the same ^meanings as the alkyl groups, aryl groups, and alkoxy groups described in Substituent Group V above.

In the general formulas (a-1) and (a-2), C ^a1 and C ^a2 each independently represent an alkyl group, preferably an alkyl group having 1 to 20 carbon atoms, more preferably 1 to 10 carbon atoms. It is. Particularly preferably, it represents a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group or a nonyl group.

Among the general formulas (a-1) and (a-2), the substituent represented by the above-{(B ¹ ) _p- (Q ¹ ) _q- (B ² ) _r } _n -C ¹ In particular, when C ^a1 and C ^a2 are linear alkyl groups having 3 to 10 carbon atoms, the solubility in the host liquid crystal is improved, and the light absorption amount in a colored state is increased, which is suitable for a light-modulating material. . The reason is not clear, but it is presumed that the compatibility with the host liquid crystal is improved.

In the general formula (1), R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ and R ⁸ are the same as the above-(Het) _m -{(B ¹ ) _p- (Q ¹ ) _Q- (B ² ) _r } When it is not a substituent represented by _n- C ¹ , each substituent may be any substituent, but a substituent selected from the substituent group V described below Is mentioned.

<Substituent group V>
Halogen atom (eg, chlorine, bromine, iodine, fluorine); mercapto group; cyano group; carboxyl group; phosphate group; sulfo group; hydroxy group; carbon number 1-10, preferably carbon number 2-8, more preferably carbon A carbamoyl group having 2 to 5 carbon atoms (for example, methylcarbamoyl group, ethylcarbamoyl group, morpholinocarbamoyl group); a sulfamoyl group having 0 to 10 carbon atoms, preferably 2 to 8 carbon atoms, more preferably 2 to 5 carbon atoms (for example, methyl). Sulfamoyl group, ethylsulfamoyl group, piperidinosulfamoyl group); nitro group; C1-C20, preferably C1-C10, more preferably C1-C8 alkoxy group (for example, methoxy) Group, ethoxy group, 2-methoxyethoxy group, 2-phenylethoxy group); 6 to 20 carbon atoms, preferably 6 to 1 carbon atoms More preferably an aryloxy group having 6 to 10 carbon atoms (for example, phenoxy group, p-methylphenoxy group, p-chlorophenoxy group, naphthoxy group); 1 to 20 carbon atoms, preferably 2 to 12 carbon atoms, more preferably Is an acyl group having 2 to 8 carbon atoms (for example, acetyl group, benzoyl group, trichloroacetyl group); an acyloxy group having 1 to 20 carbon atoms, preferably 2 to 12 carbon atoms, and more preferably 2 to 8 carbon atoms (for example, acetyl group). An oxy group, a benzoyloxy group); an acylamino group having 1 to 20 carbon atoms, preferably 2 to 12 carbon atoms, more preferably 2 to 8 carbon atoms (for example, an acetylamino group); 1 to 20 carbon atoms, preferably a carbon number. 1 to 10, more preferably a sulfonyl group having 1 to 8 carbon atoms (for example, methanesulfonyl group, ethanesulfonyl group, benzenesulfonyl group) A sulfinyl group having 1 to 20 carbon atoms, preferably 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms (for example, methanesulfinyl group, ethanesulfinyl group, benzenesulfinyl group); 1 to 20 carbon atoms, preferably carbon A sulfonylamino group having 1 to 10, more preferably 1 to 8 carbon atoms (for example, methanesulfonylamino group, ethanesulfonylamino group, benzenesulfonylamino group);

A substituted or unsubstituted amino group having 0 to 20 carbon atoms, preferably 0 to 12 carbon atoms, more preferably 0 to 8 carbon atoms (for example, an unsubstituted amino group, a methylamino group, a dimethylamino group, a benzylamino group) Anilino group, diphenylamino group); an ammonium group having 0 to 15 carbon atoms, preferably 3 to 10 carbon atoms, more preferably 3 to 6 carbon atoms (for example, trimethylammonium group or triethylammonium group); A hydrazino group having 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms (for example, trimethylhydrazino group); 1 to 15 carbon atoms, preferably 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms. Ureido group (for example, ureido group, N, N-dimethylureido group); carbon number 1-15, preferably carbon number 1-10, more preferably carbon number -6 imide group (for example, succinimide group); C1-C20, preferably C1-C12, more preferably C1-C8 alkylthio group (for example, methylthio group, ethylthio group, propylthio group); An arylthio group having 6 to 80, preferably 6 to 40, more preferably 6 to 30 carbon atoms (for example, phenylthio group, p-methylphenylthio group, p-chlorophenylthio group, 2-pyridylthio group, 1-naphthylthio group) 2-naphthylthio group, 4-propylcyclohexyl-4′-biphenylthio group, 4-butylcyclohexyl-4′-biphenylthio group, 4-pentylcyclohexyl-4′-biphenylthio group, 4-propylphenyl-2-ethynyl -4'-biphenylthio group); 1 to 80 carbon atoms, preferably 1 to 40 carbon atoms, The Mashiku heteroarylthio group having 1 to 30 carbon atoms (e.g., 2-pyridylthio group, 3-pyridylthio group, 4-pyridylthio group, 2-Kinoriruchio group, 2-furylthio group, 2-Piroriruchio group);

An alkoxycarbonyl group having 2 to 20 carbon atoms, preferably 2 to 12 carbon atoms, more preferably 2 to 8 carbon atoms (for example, a methoxycarbonyl group, an ethoxycarbonyl group, or a 2-benzyloxycarbonyl group); Preferably it is C6-C12, More preferably, it is C6-C10 aryloxycarbonyl group (for example, phenoxycarbonyl group); C1-C18, Preferably it is C1-C10, More preferably, it is C1-C5 An unsubstituted alkyl group (for example, methyl group, ethyl group, propyl group, butyl group); a substituted alkyl group having 1 to 18 carbon atoms, preferably 1 to 10 carbon atoms, more preferably 1 to 5 carbon atoms {for example, hydroxy Methyl group, trifluoromethyl group, benzyl group, carboxyethyl group, ethoxycarbonylmethyl group, acetylaminomethyl group, In this case, an unsaturated hydrocarbon group having 2 to 18 carbon atoms, preferably 3 to 10 carbon atoms, more preferably 3 to 5 carbon atoms (for example, vinyl group, ethynyl group 1-cyclohexenyl group, benzylidine group, benzylidene group). Are also included in the substituted alkyl group}; a substituted or unsubstituted aryl group having 6 to 20 carbon atoms, preferably 6 to 15 carbon atoms, more preferably 6 to 10 carbon atoms (for example, a phenyl group, a naphthyl group, p-carboxyphenyl group, p-nitrophenyl group, 3,5-dichlorophenyl group, p-cyanophenyl group, m-fluorophenyl group, p-tolyl group, 4-propylcyclohexyl-4'-biphenyl, 4-butylcyclohexyl -4'-biphenyl, 4-pentylcyclohexyl-4'-biphenyl, 4-propylphenyl-2-ethynyl-4 -Biphenyl); a substituted or unsubstituted heterocyclic group having 1 to 20 carbon atoms, preferably 2 to 10 carbon atoms, more preferably 4 to 6 carbon atoms (for example, pyridyl group, 5-methylpyridyl group, thienyl group, furyl). Group, morpholino group, tetrahydrofurfuryl group). These substituent groups V can have a structure in which a benzene ring or a naphthalene ring is condensed. Furthermore, any substituent selected from the substituent group V may be further substituted on these substituents.

  Preferred as the substituent group V is a hydroxy group, an arylthio group having 6 to 80 carbon atoms, more preferably 6 to 40 carbon atoms, still more preferably 6 to 30 carbon atoms (for example, phenylthio, p-methylphenylthio, p- Chlorophenylthio, 4-methylphenylthio, 4-ethylphenylthio, 4-n-propylphenylthio, 2-n-butylphenylthio, 3-n-butylphenylthio, 4-n-butylphenylthio, 2-t -Butylphenylthio, 3-t-butylphenylthio, 4-t-butylphenylthio, 3-n-pentylphenylthio, 4-n-pentylphenylthio, 4-amylpentylphenylthio, 4-hexylphenylthio, 4-heptylphenylthio, 4-octylphenylthio, 4-trifluoromethylphenylthio, 3-tri Fluoromethylphenylthio, 2-pyridylthio, 1-naphthylthio, 2-naphthylthio, 4-propylcyclohexyl-4′-biphenylthio, 4-butylcyclohexyl-4′-biphenylthio, 4-pentylcyclohexyl-4′-biphenylthio 4-propylphenyl-2-ethynyl-4′-biphenylthio), a heteroarylthio group having 1 to 80 carbon atoms, more preferably 1 to 40 carbon atoms, and still more preferably 1 to 30 carbon atoms (for example, 2-pyridylthio). , 3-pyridylthio, 4-pyridylthio, 2-quinolylthio, 2-furylthio, 2-pyrrolylthio), substituted or unsubstituted alkylthio groups (for example, methylthio, ethylthio, butylthio, phenethylthio), substituted or unsubstituted amino groups ( For example, amino, methylamino, dimethyl Amino, benzylamino, anilino, diphenylamino, 4-methylphenylamino, 4-ethylphenylamino, 3-n-propylphenylamino, 4-n-propylphenylamino, 3-n-butylphenylamino, 4-n- Butylphenylamino, 3-n-pentylphenylamino, 4-n-pentylphenylamino, 3-trifluoromethylphenylamino, 4-trifluoromethylphenylamino, 2-pyridylamino, 3-pyridylamino, 2-thiazolylamino, 2- Oxazolylamino, N, N-methylphenylamino, N, N-ethylphenylamino), halogen atom (eg, fluorine atom, chlorine atom), substituted or unsubstituted alkyl group (eg, methyl, trifluoromethyl) , Substituted or unsubstituted alkoxy groups ( For example, methoxy, trifluoromethoxy), substituted or unsubstituted aryl group (eg, phenyl), substituted or unsubstituted heteroaryl group (eg, 2-pyridyl), substituted or unsubstituted aryloxy group (eg, phenoxy) ), A substituted or unsubstituted heteroaryloxy group (for example, 3-thienyloxy) and the like.

  The substituent group V is more preferably the above-mentioned alkyl group, aryl group, alkoxy group, aryloxy group, halogen atom, unsubstituted amino group, substituted amino group, hydroxy group, alkylthio group, and arylthio group, and more preferably , Oxygen atom, sulfur atom or nitrogen atom, for example, hydroxy group, alkoxy group, aryloxy group, alkylthio group, arylthio group, unsubstituted amino group, substituted amino group (alkylamino group, arylamino group) Among them, a hydroxy group is particularly preferable.

R ¹ , R ⁴ , R ⁵ and R ⁸ are each independently a hydrogen atom, alkyl group, aryl group, alkoxy group, aryloxy group, halogen atom, amino group, substituted amino group, hydroxy group, alkylthio group or It is preferably an arylthio group, more preferably a hydrogen atom, an amino group, a substituted amino group, a hydroxy group, an arylthio group or an aryl group, and at least one of R ¹ , R ⁴ , R ⁵ and R ⁸ is More preferably, it is a hydroxy group.
In particular, at least R ¹ is preferably a hydroxy group, and R ¹ and R ⁵ are preferably a hydroxy group from the viewpoint that the maximum absorption wavelength is in the visible range.

  Although the specific example of the dichroic dye which can be used for this invention below is shown, this invention is not limited at all by the following specific examples.

  The dichroic dye represented by the general formula (1) can be synthesized by combining known methods. For example, it can be synthesized according to the method described in JP-A No. 2003-192664.

(Host LCD)
The host liquid crystal that can be used in the light control material of the present invention changes the alignment state by the action of an electric field, and the alignment state of the dichroic dye represented by the general formula (1) dissolved as a guest It is defined as a compound having a function of controlling.
The host liquid crystal usable in the present invention is not particularly limited as long as it can coexist with the dichroic dye, but a liquid crystal compound exhibiting a nematic phase can be used. Specific examples of nematic liquid crystal compounds include azomethine compounds, cyanobiphenyl compounds, cyanophenyl esters, fluorine-substituted phenyl esters, cyclohexanecarboxylic acid phenyl esters, fluorine-substituted cyclohexanecarboxylic acid phenyl esters, cyanophenylcyclohexane, fluorine-substituted phenylcyclohexane, and cyano-substituted. Examples include phenyl pyrimidine, fluorine-substituted phenyl pyrimidine, alkoxy-substituted phenyl pyrimidine, fluorine-substituted alkoxy-substituted phenyl pyrimidine, phenyl dioxane, tolan compounds, fluorine-substituted tolan compounds, alkenyl cyclohexyl benzonitrile and the like. The liquid crystal compounds described on pages 154 to 192 and pages 715 to 722 of “Liquid Crystal Device Handbook” (Japan Society for the Promotion of Science 142nd edition, Nikkan Kogyo Shimbun, 1989) can be used. For example, Merck's liquid crystal (ZLI-4692, MLC-6267, 6284, 6287, 6288, 6406, 6422, 6423, 6425, 6435, 6437, 7700, 7800, 9000, 9100, 9200, 9300, 10,000, etc.) Liquid crystal (LIXON 5036xx, 5037xx, 5039xx, 5040xx, 5041xx, etc.) of Asahi Denka Co., Ltd. (HA-11757).

The dielectric anisotropy of the host liquid crystal used in the present invention may be positive or negative.
When the host liquid crystal with positive dielectric anisotropy is horizontally aligned, the liquid crystal is horizontally aligned when no voltage is applied, so that the dichroic dye is also horizontal and absorbs light. On the other hand, since the liquid crystal molecules are tilted vertically when a voltage is applied, the dichroic dye is also tilted vertically, so that light is transmitted. That is, it is transparent when a voltage is applied and colored when no voltage is applied.
When the host liquid crystal having a negative dielectric anisotropy is vertically aligned, when no voltage is applied, the liquid crystal is vertically aligned, so that the dichroic dye is also vertical and transmits without absorbing light. On the other hand, since the liquid crystal molecules are tilted horizontally when a voltage is applied, the dichroic dye is also tilted horizontally, and as a result, absorbs light. That is, it is in a transparent state when no voltage is applied, and in a colored state when a voltage is applied.

In order to become a liquid crystal having a negative dielectric anisotropy, it is necessary to have a structure in which the dielectric anisotropy is increased on the short axis of the liquid crystal molecule. For example, “Monthly Display” (April 2000 issue) ), Pages 4-9, Syn Lett. , Vol. 4, pages 389 to 396, 1999. For example, Merck's liquid crystal (such as ZLI-2806) may be used. Among these, from the viewpoint of voltage holding ratio, a liquid crystal having a fluorine-based substituent and having a negative dielectric anisotropy is preferable. For example, Merck liquid crystal (MLC-6608, 6609, 6610, etc.) can be mentioned.
Furthermore, the light control material of this invention can also use the liquid crystal which shows dual wavelength drivability. Dual frequency drive liquid crystal indicates positive dielectric anisotropy when the frequency of the electric field applied to the liquid crystal is in the low frequency region, and the sign of the dielectric anisotropy is reversed negative in the high frequency region. It is a liquid crystal. For details, refer to Japan Society for the Promotion of Science 142nd Committee, Liquid Crystal Device Handbook, Nikkan Kogyo Shimbun, 1989, pages 189-192.
The refractive index anisotropy (Δn) of the host liquid crystal used in the present invention is preferably a small absolute value of Δn when switching between the transparent coloring state and the transparent state, and when switching between the scattering coloring state and the transparent state. Preferably, the absolute value of Δn is small. The refractive index anisotropy (Δn) here is defined as the difference between the refractive index (n‖) in the major axis direction of the liquid crystal molecules and the refractive index (n⊥) in the minor axis direction of the liquid crystal molecules.

  Δn = n‖−n⊥

When the phase transition method is used as a method for switching between the transparent coloring state and the transparent state, a liquid crystal having a small Δn absolute value is preferably Δn = 0.1 or less. When Δn is small, the wave guide in the spiral structure is suppressed, light leakage is reduced, and the light control performance is improved.
On the other hand, when the phase transition method is used as a method for switching between the scattering colored state and the transparent state, a liquid crystal having a large absolute value of Δn is preferably Δn = 0.1 or more. More preferably, Δn = 0.12 or more. This is because, in the scattering state based on the random focal conic state, the scattering intensity increases as Δn of the host liquid crystal increases, and the dimming performance improves.

  Although there is no restriction | limiting in particular about content of the host liquid crystal and dichroic dye in the light control material of this invention, Content of dichroic dye is 0.1-15 mass% with respect to content of a host liquid crystal. It is preferably 0.5 to 10% by mass, more preferably 1 to 8% by mass. In addition, the contents of the host liquid crystal and the dichroic dye were prepared by preparing a liquid crystal composition containing both, measuring the absorption spectrum of the liquid crystal cell in which the liquid crystal composition was sealed, and obtaining the desired optical density as the liquid crystal cell. It is desirable to determine the dye concentration necessary to indicate.

(Other additives)
The light control material of the present invention is a compound that does not exhibit liquid crystallinity for the purpose of changing the physical properties of the host liquid crystal to a desired range (for example, for the purpose of setting the temperature range of the liquid crystal phase to a desired range). May be added. Moreover, you may contain compounds, such as a chiral compound, a ultraviolet absorber, and antioxidant. Examples of such additives include chiral agents for TN and STN described in pages 199 to 202 of “Liquid Crystal Device Handbook” (edited by the Japan Society for the Promotion of Science 142nd Committee, Nikkan Kogyo Shimbun, 1989). It is done. When the chiral agent is added, a cholesteric liquid crystal phase is formed, and the dichroic dye dissolved in the nematic liquid crystal is arranged in a spiral shape. Therefore, since both polarized light can be absorbed with respect to linearly polarized light orthogonal to each other, the amount of light absorption in the colored state increases. Therefore, it is preferable. On the other hand, when a uniaxially aligned nematic liquid crystal layer is used, only half of the light is theoretically absorbed.

  The addition amount of the chiral agent is preferably 1 to 30% by mass in the liquid crystal composition, more preferably 1.5 to 20% by mass, and still more preferably 2 to 10% by mass. When the amount is more than 30% by mass, selective reflection may be exhibited in the visible range, and the dimming performance may be deteriorated, or the chiral agent may be easily deposited from the host liquid crystal. A plurality of chiral agents may be used. In particular, it is preferable that the temperature dependence of the chiral pitch is reduced by using a combination of a positive and negative temperature dependence of the chiral pitch.

Specific examples of the chiral agent used in the present invention are shown below.

  About the light control performance in the light control material of this invention, it is preferable that the ratio (transparent state / colored state) of the light transmittance in the colored state and a transparent state is the range of 3-1000. More preferably, it is the range of 5-1000, Most preferably, it is the range of 8-1000.

The liquid crystal composition used for the light control material of the present invention may coexist with a polymer. In the case where the light-modulating material of the present invention is a method of switching between a scattering colored state and a transparent state, it is preferable to coexist with a polymer.
The polymer medium layer containing the liquid crystal composition used for the light modulating material of the present invention can be formed, for example, by coating a polymer solution in which the liquid crystal composition is dispersed on a substrate. As a method of dispersing the liquid crystal composition in the polymer solution, mechanical stirring, heating, ultrasonic waves, or a combination thereof can be used.

  In the polymer medium layer, the mass ratio between the liquid crystal composition dispersed in the polymer medium and the polymer medium is preferably 1:10 to 10: 1, and more preferably 1: 1 to 8: 2.

As a method for forming the polymer medium layer, a solution in which a polymer and a liquid crystal composition are dissolved is applied on the substrate, or after the liquid crystal composition and the polymer are dissolved in a common solvent, A method in which the solvent is evaporated and the solvent is evaporated is preferred.
There is no restriction | limiting in particular in the polymer used for the said polymer medium layer. Water-soluble polymers such as siloxane polymers, methylcellulose, polyvinyl alcohol, polyoxyethylene, polyvinyl butyral, gelatin, polyacrylates, polymethacrylates, polyamides, polyesters, polycarbonates, polyvinyls such as vinyl acetate and polyvinyl butyral Water-insoluble polymers such as alcohol derivatives, cellulose derivatives such as triacetylcellulose, polyurethanes, and styrenes are used. As the polymer used in the light control material of the present invention, siloxane polymers, polyacrylates, and polymethacrylates are preferable from the viewpoint of high compatibility with the host liquid crystal.

  Specific examples of the siloxane polymer of the present invention are shown below, but the present invention is not limited thereto.

Furthermore, a surfactant can be used in the polymer medium layer for the purpose of stabilizing the dispersion of the liquid crystal composition. There is no particular limitation on the surfactant applicable to the present invention, but nonionic surfactants are preferable, and sorbitan fatty acid esters, polyoxyethylene fatty acid esters, polyoxyethylene alkyl ethers, fluoroalkylethylene oxides, etc. are used. It is done.
In particular, since the dichroic dye according to the present invention has a structure represented by the general formula (1), when a polymer having an aromatic group is used, the compatibility with the polymer is increased and the light control performance is improved. Can be increased.

    In the light modulating material of the present invention, the thickness of the polymer medium layer is preferably 1 to 50 μm, more preferably 2 to 40 μm, and still more preferably 5 to 30 μm.

In the case of a light-modulating material, it is particularly preferable to add a large amount of dichroic dye because the light-modulating performance is improved. At the same time, as a method for preparing a polymer-dispersed liquid crystal, a polymer phase separation that tends to increase the scattering intensity. When the method (method (1) above) is applied, the polymerization temperature is preferably lower than room temperature from the viewpoint of suppressing the decomposition of the dichroic dye by radical species during polymerization. Moreover, when the reactivity by radical species is low, there exists an effect which suppresses decomposition | disassembly of a dichroic dye, From the viewpoint, it is preferable to use a methacrylate-type monomer. Further, when utilizing photopolymerization, it is preferable to reduce the UV irradiation intensity from the viewpoint of suppressing the decomposition of the dichroic dye during UV irradiation, for example, a range of 1 to 500 mW / cm ² is preferable. More preferably, it is the range of 1-50 mW / cm < ² >. When applying a method (phases (2) to (4) above) in which a polymer and a liquid crystal composition are mixed in advance before phase separation is applied, the applied polymer has a viewpoint of reducing dyeing of a dichroic dye. From the above, a polymer having no aromatic group is preferable. For example, polyacrylate, polymethacrylate, polyvinyl alcohol, gelatin, polyimide and the like are preferable. The above measures are preferable because the transmittance in the transparent state is increased. In addition, when the additive concentration of the chiral agent is adjusted so that the selective reflection band comes in the near-infrared region, the number of spirals increases and the light absorption rate by the dichroic dye increases. Is preferred.

  In the light control material of the present invention, a plurality of dichroic dyes may be mixed in one liquid crystal layer. Any color may be presented. Further, the liquid crystal layers exhibiting the respective colors may be stacked as separate layers. Furthermore, liquid crystal layers (liquid crystal portions) exhibiting respective colors may be juxtaposed.

<Configuration of light control material>
(Basic structure)
The light control material should just have the liquid crystal layer containing a host liquid crystal and a dichroic dye at least. Therefore, a mode in which a liquid crystal layer is simply present between a pair of supports or a mode in which a liquid crystal layer is present between a pair of electrode substrates and the light control state is electrically controlled (a light control element) ). Preferably, the support and the substrate are transparent.

(Each component)
-Electrode substrate-
As the electrode substrate, a substrate in which an electrode layer is formed on a substrate usually made of glass or plastic (polymer) can be used. A plastic substrate is preferable. Examples of the plastic substrate include acrylic resin, polycarbonate resin, epoxy resin, PES, and PEN. As the substrate, for example, those described in pages 218 to 231 of “Liquid Crystal Device Handbook” (edited by the Japan Society for the Promotion of Science 142nd Committee, Nikkan Kogyo Shimbun, 1989) can be used. The electrode layer formed on the substrate is preferably a transparent electrode layer. For example, it can be formed from indium oxide, ITO (indium tin oxide), tin oxide, or the like. As for the transparent electrode, for example, those described in pages 232 to 239 of “Liquid Crystal Device Handbook” (edited by the Japan Society for the Promotion of Science 142nd Committee, Nikkan Kogyo Shimbun, 1989) are used.

-Spacer-
The light-modulating material of the present invention can be produced, for example, by placing a pair of substrates facing each other at intervals of 1 to 50 μm via a spacer or the like, and disposing a liquid crystal composition in a space formed between the substrates. As the spacer, for example, those described in pages 257 to 262 of “Liquid Crystal Device Handbook” (edited by Japan Society for the Promotion of Science 142nd Committee, Nikkan Kogyo Shimbun, 1989) can be used. The light control material of this invention can be arrange | positioned in the space between board | substrates by apply | coating or printing on a board | substrate.
In the case of the light modulating material of the present invention, the thickness of the liquid crystal layer, that is, the distance between the substrates formed by the spacers is preferably 1 to 50 μm, more preferably 2 to 40 μm. If it is thicker than 50 μm, the transmittance in a transparent state tends to decrease, and if it is thinner than 1 μm, display unevenness tends to occur due to energization due to a partial defect, which is not preferable.

-Other components-
Examples of other members include a barrier film, an ultraviolet absorbing layer, an antireflection layer, a hard coat layer, a stain prevention layer, an organic interlayer insulating film, a metal reflector, a retardation plate, and an alignment film. These may be used alone or in combination of two or more.

The barrier film may be any of organic polymer type, inorganic type, and organic-inorganic composite type. Examples of the organic polymer system include ethylene-vinyl alcohol (EVOH), polyvinyl alcohol (PVA / PVOH), nylon MXD6 (N-MXD), and nanocomposite nylon. Examples of the inorganic system include silica, alumina, and binary system. Details thereof are described, for example, in “Development of High Barrier Materials, Film Formation Technology and Barrier Properties Measurement / Evaluation Method” (Technical Information Association, 2004).
In the light modulating material of the present invention, the barrier layer is preferably installed on the surface side where the transparent electrode on the support is not installed from the viewpoint of ease of production.

As the ultraviolet absorbing layer, an antioxidant such as 2,2-thiobis (4-methyl-6-tert-butylphenol), 2,6-di-tert-butylphenol: 2- (3-tert-butyl-5-methyl) It is preferable to contain ultraviolet absorbers such as 2-hydroxyphenyl) -5-chlorobenzotriazole and alkoxybenzophenone.
In the light control material of the present invention, the ultraviolet absorbing layer is preferably installed on the surface side where the transparent electrode on the support is not installed from the viewpoint of ease of production.

  The antireflection film is formed using an inorganic material or an organic material, and the film configuration may be a single layer or a multilayer. Furthermore, a multilayer structure of an inorganic material film and an organic material film may be used. The antireflection film can be provided on one side or both sides of the light control material. When provided on both sides, the antireflection films on both sides may have the same configuration or different configurations. For example, the antireflection film on one surface may have a multilayer structure, and the antireflection film on the other surface side may be simplified to have a single layer structure. Further, an antireflection film can be directly provided on the transparent electrode or the support.

The inorganic material used for the antireflection _{film, SiO 2, SiO, ZrO 2} , TiO 2, TiO, Ti 2 O 3, Ti 2 O 5, Al 2 O 3, Ta 2 O 5, CeO 2, MgO, Y 2 O ₃ , SnO ₂ , MgF ₂ , WO _{3 and the} like can be mentioned, and these can be used alone or in combination of two or more. Among these, since the lens is a plastic lens, SiO ₂ , ZrO ₂ , TiO ₂ , and Ta ₂ O ₅ that can be vacuum-deposited at a low temperature are preferable.
As a multilayer film formed of an inorganic material, the total optical film thickness of the ZrO ₂ layer and the SiO ₂ layer from the lens side is λ / 4, the optical film thickness of the ZrO ₂ layer is λ / 4, and the outermost SiO ₂ layer is SiO _2. A laminated structure in which a high refractive index material layer and a low refractive index material layer having an optical film thickness of λ / 4 are alternately formed is exemplified. Here, λ is a design wavelength, and usually 520 nm is used. The outermost layer is preferably made of SiO ₂ because it has a low refractive index and can impart mechanical strength to the antireflection film.
In the case of forming an antireflection film with an inorganic material, for example, a vacuum deposition method, an ion plating method, a sputtering method, a CVD method, a method of depositing by a chemical reaction in a saturated solution, or the like can be employed.

  Examples of the organic material used for the antireflection film include FFP (tetrafluoroethylene-hexafluoropropylene copolymer), PTFE (polytetrafluoroethylene), ETFE (ethylene-tetrafluoroethylene copolymer), and the like. The refractive index of the lens material and the hard coat film (if any) is selected. As a film forming method, a film can be formed by a coating method having excellent mass productivity such as a spin coating method and a dip coating method in addition to a vacuum deposition method.

As the hard coat layer, a known ultraviolet curing or electron beam curing acrylic or epoxy resin can be used.
As the antifouling film, a water / oil repellent material such as a fluorine-containing organic polymer can be used.

As the alignment film, it is preferable to use a polyimide, a silane coupling agent, polyvinyl alcohol, gelatin, a silica vapor deposition film, etc., and using a polyimide or a silane coupling agent is preferable from the viewpoint of alignment ability, durability, insulation, and cost. To preferred. The alignment film may be either a horizontal alignment film or a vertical alignment film.
As for the polyimide alignment film, for example, “Liquid Crystal Handbook” (edited by the Liquid Crystal Handbook Editorial Committee, Maruzen, 2000), pages 253 to 258, “Cutting edge of liquid crystal display” (Liquid Crystal Young Research Group, The materials described in pages 83 to 104 of Sigma Publishing (1996) can be used.

When a vertical alignment film is used as the polyimide alignment film of the present invention, it is preferable to have a high vertical alignment capability, so-called vertical anchoring force. By using a polyimide film with improved vertical alignment capability, the contrast ratio of the light control material of the present invention is improved. As the polyimide film having improved vertical alignment ability, a structure in which the alkyl chain length of the polyimide side chain is extended to increase the hydrophobicity, and a structure in which the introduction rate of the diamine moiety having a long alkyl chain is increased is preferable.
On the other hand, when a horizontal alignment film is used as the polyimide alignment film of the present invention, a film having high horizontal alignment capability, so-called horizontal anchoring force, is preferable. By using a polyimide film with improved horizontal alignment capability, the contrast ratio of the light control material of the present invention is improved. As the polyimide film having enhanced horizontal alignment ability, a structure in which hydrophilicity is enhanced by shortening the alkyl chain of the polyimide side chain or introducing a hydrophilic functional group is preferable.

  Examples of the polyimide alignment film include International Patent No. 2002/051909, JP-A-7-301805, JP-A-62-297819, JP-A-1-262527, JP-A-1-262528, and JP-A-5-43688. JP, 6-82794, JP 2003-96070, JP 2003-114437, JP 2004-18422, JP 2004-163724, JP 2005-105019, JP 2005-170818. Alignment films described in JP 2000-104073, JP 2001-108831, JP 2001-100038, JP 2001-100040, and JP 2001-100041 are preferably used.

The orientation method may or may not be rubbed. As the rubbing treatment, a rubbing treatment with a cloth is used, and for example, the method described on pages 83 to 104 of “Cutting edge of liquid crystal display” (edited by Young Research Group for Liquid Crystals, Sigma Publishing, 1996) is preferably used.
The polyimide alignment film can be attached by coating, printing, or the like. Usually, a process of converting to a polyimide film by applying and baking a polyamic acid solution, or a method of forming a polyimide film by applying a solution in which polyimide is dissolved and distilling off the solvent is preferable. When a glass substrate is used, the firing temperature is preferably around 200 ° C. When a film substrate is used, it is preferable to fire at a temperature lower than the Tg temperature of the film substrate. In particular, in the case of a PEN film, the case of 120 ° C. or lower is preferable.

The film thickness of the polyimide alignment film is preferably in the range of 10 nm to 1 μm, more preferably in the range of 20 nm to 300 nm. More preferably, it is the range of 30 nm to 200 nm.
The silane coupling agent can be attached by dipping or the like. Usually, after the substrate is immersed in an alcohol solution containing a silane coupling agent, the substrate is bonded to the silane coupling agent by heating and drying.

<Application>
Since the light control material of the present invention can provide high light control performance, it can be suitably used as light control, security, in-vehicle use, interior, advertisement, and information display board. In particular, the light-modulating material of the present invention is excellent in weather resistance because of its high durability against light, heat and humidity, and can be suitably used in outdoor applications and harsh environments. The harsh environment includes in-vehicle use and use in a bathroom.

  The present invention will be described more specifically with reference to the following examples. The materials, reagents, amounts and ratios, operations, etc. shown in the following examples can be appropriately changed without departing from the gist of the present invention. Therefore, the scope of the present invention is not limited to the following specific examples. .

[Example 1]
<Preparation of light control material>
1. Preparation of dichroic dye and liquid crystal The dichroic dyes shown in Table 1 below were synthesized according to the method described in JP-A No. 2003-192664. Host liquid crystal ZLI-1132 (nematic liquid crystal) and chiral agent R-1011 were purchased from Merck.

2. Preparation of light control device A polyimide horizontal alignment film (manufactured by Nissan Chemical Co., Ltd.) was attached on a glass substrate with ITO as a transparent electrode by spin coating and baking. Next, the obtained glass substrate with a horizontal alignment film was rubbed.
In 1.0 g of host liquid crystal (ZLI-1132), the dichroic dyes shown in Table 1 below and a chiral agent (R-1011, manufactured by Merck & Co., Inc.) are heated and dissolved in the combinations shown in Table 2. And then left at room temperature for 1 day. The amount of each dichroic dye added was adjusted so that the transmittance was 20% when the liquid crystal composition was injected into an 8 μm liquid crystal evaluation cell. A small amount of 12 μm spherical spacer (manufactured by Sekisui Chemical Co., Ltd.) is mixed with the obtained liquid crystal composition, and a photo-curing sealant (manufactured by Sekisui Chemical Co., Ltd.) is sandwiched between the glass substrate with ITO and the alignment film side in contact with the liquid crystal layer. ).

3. Evaluation The obtained light control material of the present invention was in a colored state when no voltage was applied. When a voltage (± 40 V, 100 Hz) was applied using a signal generator (manufactured by Tektronix Co., Ltd.), the liquid crystal layer became transparent. Moreover, the scattering coloring state in the maximum absorption wavelength of a dichroic dye and the UV / vis absorption spectrum measurement in a transparent state (Shimadzu UV2400) were performed, and the transmittance | permeability of a scattering coloring state and a transparent state was measured. Table 2 shows the ratio of transmittance between the colored state and the transparent state (T (transparent) / T (during coloring)).
As shown in Table 2, it was confirmed that the light control material of the present invention has a light control function capable of electrically controlling light transmittance.

[Comparative Example 1]
A dimming element was prepared in the same manner as in Example 1 except that the yellow dye Y-1, magenta dye M-1, and cyan dye C-1 shown below were used, and evaluated in the same manner as in Example 1. The results are shown in Table 2.
As shown in Table 2, it was revealed that the comparative light control device had a low transmittance ratio and a low light control function as compared with the light control device of the present invention.

［実施例２］
＜調光材料の調製＞
１．プラスチック基板の作製
特開２０００−１０５４４５号公報の実施例１の試料１１０の作製と同様にＰＥＮ（Ｄｕｐｏｎｔ−Ｔｅｉｊｉｎ Ｑ６５Ａ）に対し下塗り層及びバック層を作成した。すなわち、ポリエチレン−２，６−ナフタレートポリマー１００重量部と紫外線吸収剤としてＴｉｎｕｖｉｎ Ｐ．３２６（チバ・ガイギーＣｉｂａ−Ｇｅｉｇｙ社製）２重量部とを乾燥した後、３００℃にて溶融後、Ｔ型ダイから押し出し、１４０℃で３．３倍の縦延伸を行ない、続いて１３０℃で３．３倍の横延伸を行い、さらに２５０℃で６秒間熱固定して厚さ９０μｍの本発明のプラスチック基板（ＰＥＮ）を得た。

[Example 2]
<Preparation of light control material>
1. Production of Plastic Substrate An undercoat layer and a back layer were produced for PEN (Dupont-Teijin Q65A) in the same manner as in the production of Sample 110 of Example 1 of JP-A-2000-105445. That is, 100 parts by weight of polyethylene-2,6-naphthalate polymer and Tinuvin P.I. 326 (manufactured by Ciba-Geigy Ciba-Geigy) was dried, melted at 300 ° C., extruded from a T-die, and stretched 3.3 times at 140 ° C., followed by 130 ° C. The plastic substrate (PEN) of the present invention having a thickness of 90 μm was obtained by performing transverse stretching of 3.3 times and further heat setting at 250 ° C. for 6 seconds.

2. Preparation of transparent electrode layer Conductive indium tin oxide (ITO) was coated on one surface of the plastic substrate obtained above, and a uniform thin film having a thickness of 200 nm was laminated. The surface resistance was about 20 Ω / cm ² , and the light transmittance (500 nm) was 85%. Next, a SiO ₂ thin film (100 nm) was provided as an antireflection film on the ITO surface by sputtering. The light transmittance (500 nm) was 90%.

(Preparation of liquid crystal layer)
A liquid crystal layer was prepared in the same manner as in Example 1 using the above support. However, an 8 μm adhesive spherical spacer (catalyst chemical product) was used. As the alignment film, a polyimide vertical alignment film (manufactured by Nissan Chemical Industries, SE1211) was used, and MLC-6609 (manufactured by Merck) was used as the host liquid crystal. R-1011 (manufactured by Merck) was used as the chiral agent.

(Attachment of barrier layer)
Preparation of Organic-Inorganic Hybrid Layer Soarnol D2908 (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., ethylene-vinyl alcohol copolymer) was dissolved at 80 ° C. in a mixed solvent of 18.8 g of 1-propanol and 73.2 g of water. 2.4 ml of 2N hydrochloric acid was added to 10.72 g of this solution and mixed. While stirring this solution, 1 g of tetraethoxysilane was added dropwise and stirring was continued for 30 minutes. Subsequently, the obtained coating liquid was applied with a wire bar on the support of the light control material. Thereafter, an organic-inorganic hybrid layer having a film thickness of about 1 μm was formed on the light control material by drying at 120 ° C. for 5 minutes.

(Attachment of UV absorbing layer)
After mixing 42 g of water, 40 g of silanol-modified polyvinyl alcohol (manufactured by Kuraray Co., Ltd .: trade name R2105) and 13.5 g of the capsule solution for ultraviolet filter, 50% by mass of 2- (3-tert-butyl-5-methyl-2-) 17 g of an aqueous solution of hydroxyphenyl) -5-chlorobenzotriazole, 65 g of a 20% by mass colloidal silica dispersion (manufactured by Nissan Chemical Co., Ltd .: trade name Snowtex 0), polyoxyethylene alkyl ether phosphate (manufactured by Toho Chemical Co., Ltd .: Neoscore CM57 ) 2.5 g and 2.5 g of polyethylene glycol dodecyl ether (manufactured by Kao Corporation: Emulgen 109P) were mixed to obtain a coating solution for an ultraviolet filter layer.

  Next, the obtained coating solution was applied with a wire bar onto the barrier layer of the light control material. Thereafter, an ultraviolet absorbing layer having a film thickness of about 1 μm was formed on the light-modulating material by drying at 120 ° C. for 5 minutes.

  Subsequently, the light control materials of Samples L, M, and N were prepared by the same operation as in Example 1. The light-modulating material of the present invention was transparent when no voltage was applied, and changed to a colored state when the voltage was applied. Further, the light control materials of the comparative samples O, P, and Q were prepared by the same operation as in Comparative Example 1, except that the above support was used.

(Evaluation of display performance)
When the obtained light control material of the present invention was evaluated in the same manner as in Example 1, it was confirmed that light control with a high contrast ratio was possible.
Furthermore, as shown in FIG. 1, the obtained light control material 10 was adhered to the inside of the automobile windshield 20 using an adhesive, and it was confirmed that the scattering colored state and the colorless and transparent state can be switched electrically. . That is, it was confirmed that the display element of the present invention functions as a sun visor.
Moreover, as shown in FIG. 2, the obtained light control material 10 was attached to the glass part of the door 30, and it confirmed that the scattering coloring state and the colorless and transparent state were switched electrically. That is, it was confirmed that the display element of the present invention functions as a door having a dimming function.

(Evaluation of light resistance)
The light resistance was evaluated. When the light control material was irradiated with Xe lamp (150,000 lux) (480 hours), the light control material of the present invention did not change in electrical characteristics. The light absorption rate in the colored state was visually reduced, and it was confirmed that the light control function was lowered. That is, it was confirmed that the light control material of the present invention is excellent in light resistance.
Table 3 shows the results of measuring the ratio (%) of the light absorption after the light resistance evaluation to the light absorption before the light resistance evaluation for the light absorption ratio in the colored state.

(Evaluation of heat resistance)
The heat resistance was evaluated. The electrical characteristics were evaluated after storing the light-modulating material in an oven set at 85 ° C. for 1 week, and the electrical characteristics of the light-modulating material of the present invention were not changed. It was confirmed that the light absorption rate of the transparent material at the time of voltage application decreased visually, and the light control function was falling. That is, it was confirmed that the light control material of the present invention is excellent in heat resistance.
Table 4 shows the results of measuring the ratio (%) of the absorptance after the heat resistance evaluation to the absorptance before the heat resistance evaluation for the light absorptance in the transparent state.

(Evaluation of heat and humidity durability)
Evaluation of heat and humidity durability was performed. The electrical characteristics were evaluated after storing the light-modulating material for 1 week in a constant temperature oven set at a humidity of 80% and a temperature of 60 ° C. As a result, the electrical characteristics of the light-modulating material of the present invention were not changed. However, it was confirmed that the comparative light-modulating material had a reduced light absorption rate in a transparent state when a voltage was applied, and the light-modulating function was lowered. That is, it was confirmed that the light control material of the present invention is excellent in thermal humidity durability.
Table 5 shows the results of measuring the ratio (%) of the absorption rate after the evaluation of the thermal humidity durability to the absorption rate before the evaluation of the thermal humidity durability for the light absorption rate in the transparent state.

The figure which used the light control material element of this invention for the inner side of the motor vehicle windshield. The figure which attached the light control material element of this invention to the glass part of the door.

Explanation of symbols

10 Light control material
20 Windshield
30 Glass part of the door

Claims (15)

A liquid crystal layer containing at least one kind of dichroic dye represented by the following general formula (1) and at least one kind of host liquid crystal is provided between a pair of electrodes, and transmits incident light. Dimmable material.

[Wherein R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ and R ⁸ each independently represent a hydrogen atom or a substituent, R ² , R ³ , R ⁶ and At least one of R ⁷ represents a substituent represented by-(Het) _m -{(B ¹ ) _p- (Q ¹ ) _q- (B ² ) _r } _n -C ¹ . Het represents an oxygen atom, a sulfur atom or NR, and R represents a hydrogen atom, an alkyl group, an aryl group or a heteroaryl group. B ¹ and B ² each independently represent a divalent aryl group, heteroaryl group or cyclic aliphatic hydrocarbon group, Q ¹ represents a divalent linking group, C ¹ represents an alkyl group, a cycloalkyl group, Represents an alkoxy group, an acyl group, an alkoxycarbonyl group or an acyloxy group; m represents 0 or 1, p, q and r each represent an integer of 0 to 5, n represents an integer of 1 to 3, but (p + r) × n is 3 to 10 is there. When p, q and r are each 2 or more, 2 or more B ¹ , Q ¹ and B ² may be the same or different. When n is 2 or more, 2 or more {(B ¹ ) _p − (Q ¹ ) _q- (B ² ) _r } may be the same or different. ] In the general formula (1), at least R ² is a substituent represented by-(Het) _m -{(B ¹ ) _p- (Q ¹ ) _q- (B ² ) _r } _n -C ^1. The light control material according to claim 1, wherein the light control material is provided. In the general formula (1), any two of R ² , R ³ , R ⁶ and R ⁷ are the-(Het) _m -{(B ¹ ) _p- (Q ¹ ) _q- (B ² ) _r. } the light modulating material according to claim 1 or claim 2, characterized in that a substituent represented by _n -C ^1. In the general formula (1), R ² and R ⁶ are the substituents represented by-(Het) _m -{(B ¹ ) _p- (Q ¹ ) _q- (B ² ) _r } _n -C ^1. it is, or the ^{R 2} and _{^{R 3 - (Het) m -}} {(B 1) p - (Q 1) q - (B 2) r} be a substituent represented by n -C ¹ The light control material according to claim 3. 5. The process according to claim 1, wherein at least one of R ¹ , R ⁴ , R ⁵ , and R ^{8 in} the general formula (1) is a hydroxy group. Light material. The light control material according to claim 5, wherein at least R ¹ in the general formula (1) is a hydroxy group. In said general formula (1), R < ¹ > and R < ⁵ > is a hydroxyl group, The light control material of Claim 6 characterized by the above-mentioned.   In the said General formula (1), it is m = 0, p = 2, q = 0, r = 1 and n = 1, The adjustment of any one of Claim 1 thru | or 7 characterized by the above-mentioned. Light material.   The light control material according to any one of claims 1 to 8, wherein the host liquid crystal contains a chiral agent.   The light control material according to claim 1, wherein the host liquid crystal is a nematic liquid crystal.   The dimming according to any one of claims 1 to 10, wherein dimming is performed by changing between a colored state and a transparent state, or dimming is performed by changing between a scattering colored state and a transparent state. Light material.   The light control material according to claim 11, wherein a ratio of light transmittance in the colored state and the transparent state (transparent state / colored state) is in a range of 3 to 1,000.   Furthermore, it has a polymer support body, The light control material of any one of Claim 1 thru | or 12 characterized by the above-mentioned.   Furthermore, it has a ultraviolet absorption layer, The light control material of any one of Claim 1 thru | or 13 characterized by the above-mentioned.   The light control material according to any one of claims 1 to 14, wherein the light control material is used outdoors.

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