JP2011190314A - Liquid crystal composition for light control, photo-cured product thereof, and light control element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal composition for light control capable of producing a light control element that enables actuation at a low voltage and light control at a high temperature, and can attain various coloring and a haze of ≤10% at the same time, as well as to provide its photo-cured product, and a light control element using the cured product. <P>SOLUTION: The liquid crystal composition for light control which includes following components (A), (B), (C) and (D); the photo-cured product which is produced by photo-curing the component (B) of the composition; and the light control element which holds a layer of the photo-cured product of the composition between a pair of substrates composed of transparent substrates oppositely arranged are provided. The component (A) is a liquid crystal which contains a fluorine-containing and/or chlorine-containing nematic liquid with a phase transition temperature of ≥100°C. The component (B) is a photo-curable compound which contains a 5-13C alkyl group-having mono(meth)acrylate and a 4-13C linear alkylene di(meth)acrylate. The component (C) is a pigment which is represented by a specific chemical formula, and contains an anthraquinone dye with ≤4 aromatic rings. The component (D) is a photopolymerization initiator. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a light control liquid crystal composition, a photocured product thereof, and a light control device using the same.

  Films obtained by dispersing liquid crystals in polymers instead of blinds, photocuring, etc. for the purpose of privacy protection in windows, doors, partitions, etc. of trains, automobiles, business buildings, hospitals, etc. It is common to use a film with a light-modulating layer as a light-control panel using phase separation of the liquid crystal material that accompanies the photo-curing of the photo-curing vinyl-based compound in the composition of the curable vinyl compound and liquid crystal Have been doing. Normally, in such a light control panel, depending on the presence or absence of voltage application, light transmission and scattering can be controlled and light control can be performed to block the field of view. For the purpose of reducing this and improving contrast, a dye is added. In this case, for example, in providing light control performance to a window glass of an automobile, it is preferable that there is no cloudiness when it is transparent and that the field of view is good, and that dark coloring is obtained when it is cloudy.

  As such a liquid crystal composition for light control, Patent Document 1 discloses a liquid crystal composition containing a di (meth) acrylate monomer as a photocurable compound and an anthracene dichroic dye in a cyano liquid crystal. ing. Although the light control element obtained by the liquid crystal composition for light control of Patent Document 1 can be variously colored (color tone and light and shade), a high voltage of about 100 V is required for driving, and the present invention According to their verification, the operating temperature range is limited to less than 70 ° C., and therefore, it is not sufficient to realize battery operation without using a booster or operation at a high temperature as a light control element for automobiles. Furthermore, the haze representing the visibility when transparent is cut by only 10%, but only 4%.

  Patent Document 2 discloses a liquid crystal composition containing cyano liquid crystal and di (meth) acrylate, mono (meth) acrylate and anthracene dichroic dye as a photocurable compound. The light control device obtained by the liquid crystal composition for light control disclosed in Patent Document 2 can realize various coloring (color tone / shading) as well as the liquid crystal composition disclosed in Patent Document 1, and up to less than 100 ° C. Is possible. However, a high voltage of about 100 V is necessary for driving, and as a light control element for automobiles, battery driving without using a booster cannot be achieved, and further, haze is 10% or more, and when transparent The visibility is also insufficient.

JP-A-4-264193 JP-A-5-307171

  The present invention has been made in view of the above-described prior art in the liquid crystal composition for light control. Accordingly, the present invention can be driven at a low voltage and light controlled at a high temperature, and has various colors (color tones). Provided are a light control liquid crystal composition capable of obtaining a light control device capable of simultaneously achieving light and shade) and a haze of 10% or less, a photocured product thereof, and a light control device using the same. With the goal.

  As a result of intensive studies in view of the above problems, the inventors of the present invention can drive at 50 V or lower, and can be dimmed up to 100 ° C. Since pigments having a wide range of colors up to yellow can be contained at a high concentration, the inventors have found that any color tone and light and shade can be achieved, and have reached the present invention.

That is, the gist of the present invention resides in a light control liquid crystal composition comprising the following components (A), (B), and (C).
Component (A): Liquid crystal component containing fluorine-containing and / or chlorine-containing nematic liquid crystal having a phase transition temperature (Tni) of 100 ° C. or higher (B) Component: linear or branched chain having 5 to 13 carbon atoms A photocurable compound component comprising a mono (meth) acrylate (B-1) component having an alkyl group and a di (meth) acrylate (B-2) component represented by the following general formula (I)

CH ₂ ═CH—C—O—X—O—C—CH═CH ₂ (I)
‖ ‖
O O

[In formula, X shows a C4-C13 linear alkylene group. ]

  Component (C): a dye component containing an anthraquinone dye represented by the following general formula (II) and having four or less aromatic rings

[In the formula (II), R ¹ is —NHR ⁸ (R ⁸ is a hydrogen atom, a linear or branched alkyl group, an optionally substituted cycloalkyl group, or a substituent. An aryl group which may be substituted, or a heterocyclic residue which may have a substituent.), Or -SR ⁹ (R ⁹ is a linear or branched alkyl group or a substituent. A cycloalkyl group that may be substituted, an aryl group that may have a substituent, or a heterocyclic residue that may have a substituent.
R ² , R ³ , and R ⁴ are each independently a hydrogen atom, —NHR ⁸ (R ⁸ is as defined above), —SR ⁹ (R ⁹ is as defined above), or — OR ¹⁰ (R ¹⁰ has a hydrogen atom, a linear or branched alkyl group, a cycloalkyl group which may have a substituent, an aryl group which may have a substituent, or a substituent. A heterocyclic residue that may be present). However, when ^one of R ^{1 to} R ⁴ is —NH ₂ , the other three are not —NH ₂ . Further, a cycloalkyl group, an aryl group, and a substituent having a heterocyclic residue of R ⁸ to R ¹⁰ does not include a coupling ring.
R ⁵ , R ⁶ , and R ⁷ each independently have a hydrogen atom, a halogen atom, a linear or branched alkyl group, an aryl group that may have a substituent, or a substituent. An aryloxy group, —SR ⁹ (R ⁹ is as defined above), or —COYR ¹¹ (Y is an oxygen atom, sulfur atom, or —NR ⁸ (R ⁸ is as defined above). R ¹¹ represents a linear or branched alkyl group, a cycloalkyl group which may have a substituent, an aralkyl group which may have a substituent, or a substituent. It represents a good aryl group or a heterocyclic residue which may have a substituent. However, when ^one of R ^{1 to} R ⁴ is —NH ₂ , at least one of R ^{5 to} R ⁷ is not a hydrogen atom. R ^{5 to} R ⁷ do not have three or more linked ring structures. ]
(D) component; photopolymerization initiator component

  The gist of the present invention is that the photocurable compound of the liquid crystal composition for light control, wherein the photocurable compound component of the component (B) of the liquid crystal composition for light control is photocured, and A light-modulating element, wherein a photocured layer of the liquid crystal composition for light control is sandwiched between a pair of substrates opposed to each other, at least one of which is a transparent substrate having a transparent electrode, Exist.

  According to the liquid crystal composition for light control of the present invention, sufficient light control performance can be obtained by driving at 50 V or less, the influence on the human body can be minimized, and at the same time energy saving can be achieved. Furthermore, since light control up to 100 ° C. is possible, it can withstand use in a high temperature environment. In addition, by mixing and combining pigments having different color tones, it is possible to obtain a light control element exhibiting an arbitrary color tone and lightness, for example, black, while suppressing the haze representing visibility when transparent to 10% or less.

I. Light control liquid crystal composition I-1. (A) Liquid Crystal Component The (A) liquid crystal component used in the light control liquid crystal composition of the present invention includes fluorine-containing and / or chlorine-containing nematic liquid crystal having a phase transition temperature (Tni) of 100 ° C. or higher. When the liquid crystal component does not contain fluorine-containing and / or chlorine-containing nematic liquid crystal, the effects of the present invention cannot be obtained.

  Here, the phase transition temperature (Tni) is preferably 130 ° C. or lower, and particularly preferably 120 ° C. or lower. If the phase transition temperature (Tni) is too low, the usable temperature range is narrowed and the dimming function is not achieved in a high temperature range. If it is too high, the viscosity near room temperature becomes high, and driving at room temperature tends to be difficult. The phase transition temperature (Tni) represents the nematic isotropic phase transition temperature of the liquid crystal, and can be evaluated by measuring a transmitted light intensity change accompanying the phase transition using a phase transition temperature measuring device.

In addition, the fluorine-containing and / or chlorine-containing nematic liquid crystal used in the light control liquid crystal composition of the present invention preferably has a large refractive index anisotropy (Δn) from the viewpoint of ensuring shielding properties when clouded. The refractive index anisotropy (Δn) of the dimmable liquid crystal composition of the present invention preferably has a large absolute value of Δn. Specifically, the refractive index anisotropy (Δn) of the liquid crystal is preferably 0.14 or more, and more preferably 0.16 or more. If the refractive index anisotropy (Δn) of the liquid crystal in the light controllable liquid crystal composition is smaller than this value, the shade of the dye corresponding to the movement of the liquid crystal can be expected, but the shielding property at the time of cloudiness is impaired. The refractive index anisotropy (Δn) referred to here is the refractive index in the major axis direction of liquid crystal molecules (n‖) and the refractive index in the minor axis direction of liquid crystal molecules (n⊥) as shown in the following formula. And is defined as the difference.
Δn = n‖−n⊥

  The basic skeleton of the fluorine-containing and / or chlorine-containing nematic liquid crystal in the present invention includes azomethine, biphenyl, phenyl ester, cyclohexanecarboxylic acid phenyl ester, phenyl cyclohexane, phenyl pyrimidine, phenyl dioxane, Examples of the liquid crystal compound include tolan series and alkenyl cyclohexyl benzene series. Examples of the liquid crystal compound include pages 154 to 192 of “Liquid Crystal Device Handbook” (Japan Society for the Promotion of Science 142nd edition, Nikkan Kogyo Shimbun, 1989). And the liquid crystal compounds described on pages 715 to 722 can be used. Specific examples include “MLC-2058” and “ZLI-1132” manufactured by Merck & Co., Inc.

I-2. (B) Photocurable compound component I-2-1. (B-1) Mono (meth) acrylate component The (B) photocurable compound component used in the light control liquid crystal composition of the present invention contains a linear or branched alkyl group having 5 to 13 carbon atoms. The mono (meth) acrylate (B-1) component which has.

  The mono (meth) acrylate used in the light control liquid crystal composition of the present invention has an effect of imparting compatibility with the liquid crystal in the light control liquid crystal composition, and the light control device of the present invention as a light control element described later. When the photocurable compound component is photocured by irradiating the liquid crystal composition with light, the liquid crystal dispersed in the photocurable compound undergoes phase separation, and the phase of the cured product of the photocurable compound and the liquid crystal phase However, mono (meth) acrylate has a function of forming a cured product phase and relaxing interfacial interaction with the liquid crystal phase. Therefore, when the polarity of mono (meth) acrylate is high, the interface interaction with the liquid crystal phase is strengthened and the movement of the liquid crystal is inhibited, and the drive voltage becomes high. preferable.

  Specific examples of the mono (meth) acrylate used in the light control liquid crystal composition of the present invention include, for example, pentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, and octyl (meth) acrylate. , Linear alkyl mono (meth) acrylates such as nonyl (meth) acrylate, decyl (meth) acrylate, undecyl (meth) acrylate, dodecyl (meth) acrylate, tridecyl acrylate, 2-methylhexyl (meth) acrylate, 2 -Branched alkyl mono (such as ethylhexyl (meth) acrylate, 2-propylhexyl (meth) acrylate, 2-methylheptyl (meth) acrylate, 2-ethylheptyl (meth) acrylate, 2-propylheptyl (meth) acrylate) Meta Acrylate is preferably used.

I-2-2. (B-2) Di (meth) acrylate component (B) The photocurable compound component used in the light control liquid crystal composition of the present invention is di (meth) acrylate (B-2) together with the mono (meth) acrylate. Including ingredients.

  The di (meth) acrylate used in the light control liquid crystal composition of the present invention is obtained by photoirradiating the photocurable compound component by irradiating the light control liquid crystal composition of the present invention as a light control element described later. In addition, the liquid crystal dispersed in the photocurable compound is phase-separated to form a cured product phase and a liquid crystal phase of the photocurable compound. The cured product phase is formed together with (meth) acrylate, and has an action for stabilizing the separated phase of the cured product phase and the liquid crystal phase. Therefore, when the polarity of di (meth) acrylate is high, the interface interaction with the liquid crystal phase is strengthened and the movement of the liquid crystal is inhibited, and the drive voltage becomes high. preferable.

  The di (meth) acrylate used in the light control liquid crystal composition of the present invention is a di (meth) acrylate represented by the following general formula (I).

CH ₂ ═CH—C—O—X—O—C—CH═CH ₂ (I)
‖ ‖
O O

[In formula, X shows a C4-C13 linear alkylene group. ]

  Specific examples of the di (meth) acrylate used in the light control liquid crystal composition of the present invention include 1,4-butanediol di (meth) acrylate and 1,5-pentanediol di (meth) acrylate. 1,6-hexanediol di (meth) acrylate, 1,7-heptanediol di (meth) acrylate, 1,8-octanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, , 10-decanediol di (meth) acrylate, 1,11-undecanediol di (meth) acrylate, 1,12-dodecanediol di (meth) acrylate, 1,13-tridecanediol di (meth) acrylate, etc. Preferably used.

I-2-3. (B-1) Mixing ratio of component and (B-2) component The mono (meth) acrylate and the di (B) as a photocurable compound component used in the light control liquid crystal composition of the present invention (B). The ratio with the (meth) acrylate is preferably 1: 9 to 9: 1, and more preferably 5: 5 to 9: 1, with the former: the latter being in a weight ratio. When mono (meth) acrylate is used alone and when the proportion of di (meth) acrylate is more than the above range, the compatibility with the liquid crystal becomes too high and it is formed by photocuring by light irradiation. Separation between the polymer phase and the liquid crystal phase does not occur sufficiently, and the gelation tends to occur. On the other hand, when di (meth) acrylate is used alone, and the ratio of mono (meth) acrylate is larger than the above range. In this case, it tends to be difficult to form a separated phase between the polymer phase and the liquid crystal phase.

I-2-4. (B) Compatibility of photocurable compound component with (A) liquid crystal component Compatibility with (A) liquid crystal component of (B) photocurable compound component used in the light control liquid crystal composition of the present invention is as follows. It can be evaluated by the phase separation temperature obtained by, for example, dissolving the liquid crystal and the photocurable compound once and observing the phase separation due to the temperature drop with a polarizing microscope or measuring by DSC. As, it is preferable that it is the range of 0-50 degreeC, and it is especially preferable that it is the range of 10-40 degreeC. If the temperature is lower than this temperature, the compatibility as the liquid crystal composition is good, but when the polymer phase and the liquid crystal phase are separated by photocuring, the phase separation tends to occur after the polymerization proceeds. Since the liquid crystal phase obtained by photocuring is small, the driving voltage as a light control element tends to be high. On the other hand, when the temperature is higher than this temperature, it tends to be difficult to maintain a uniform phase before photocuring. .

I-3. (C) Dye Component The (C) dye component used in the liquid crystal composition for light control of the present invention includes an anthraquinone dye that is represented by the following general formula (II) and has four or less aromatic rings.

[In the formula (II), R ¹ is —NHR ⁸ (R ⁸ is a hydrogen atom, a linear or branched alkyl group, an optionally substituted cycloalkyl group, or a substituent. An aryl group which may be substituted, or a heterocyclic residue which may have a substituent.), Or -SR ⁹ (R ⁹ is a linear or branched alkyl group or a substituent. A cycloalkyl group that may be substituted, an aryl group that may have a substituent, or a heterocyclic residue that may have a substituent.
R ² , R ³ , and R ⁴ are each independently a hydrogen atom, —NHR ⁸ (R ⁸ is as defined above), —SR ⁹ (R ⁹ is as defined above), or — OR ¹⁰ (R ¹⁰ has a hydrogen atom, a linear or branched alkyl group, a cycloalkyl group which may have a substituent, an aryl group which may have a substituent, or a substituent. A heterocyclic residue that may be present). However, when ^one of R ^{1 to} R ⁴ is —NH ₂ , the other three are not —NH ₂ . Further, a cycloalkyl group, an aryl group, and a substituent having a heterocyclic residue of R ⁸ to R ¹⁰ does not include a coupling ring.
R ⁵ , R ⁶ , and R ⁷ each independently have a hydrogen atom, a halogen atom, a linear or branched alkyl group, an aryl group that may have a substituent, or a substituent. An aryloxy group, —SR ⁹ (R ⁹ is as defined above), or —COYR ¹¹ (Y is an oxygen atom, sulfur atom, or —NR ⁸ (R ⁸ is as defined above). R ¹¹ represents a linear or branched alkyl group, a cycloalkyl group which may have a substituent, an aralkyl group which may have a substituent, or a substituent. It represents a good aryl group or a heterocyclic residue which may have a substituent. However, when ^one of R ^{1 to} R ⁴ is —NH ₂ , at least one of R ^{5 to} R ⁷ is not a hydrogen atom. R ^{5 to} R ⁷ do not have three or more linked ring structures. ]

In formula (II), ^{R 8} in -NHR ⁸ of ^{R 1,} and -SR ⁹ of ^{R 9, and, R} 8 of -NHR ⁸ in ^R 2 ~R ^4, R ⁹ of -SR ^9, and ^{-OR 10} As the linear alkyl group of R ¹⁰ , those having 1 to 13 carbon atoms and those having 3 to 13 carbon atoms as the branched alkyl group have a substituent. As the substituent of the cycloalkyl group, a linear alkyl group having 1 to 13 carbon atoms, a branched alkyl group having 3 to 13 carbon atoms, or the like may have a substituent. As the substituent of the aryl group, a linear alkyl group having 1 to 13 carbon atoms or a branched alkyl group having 3 to 13 carbon atoms may have a substituent. The heterocyclic residue is a pyridyl group or the like, and the substituent is a linear alkyl having 1 to 13 carbon atoms. And a cycloalkyl group having a C 1-13 branched alkyl group or a C 1-13 linear alkyl group as a substituent.

Incidentally, in formula (I), when having -NH ₂ two or more as R ¹ to R ^4, in the composition irradiated with light and light cured, a photopolymerization -NH ₂ is quench radical Since it inhibits, when one of R ^{1 to} R ⁴ is —NH ₂ , the other three are not —NH ₂ . When the cycloalkyl group, aryl group, and heterocyclic residue of R ^{8 to} R ¹⁰ have a substituent containing a linked ring structure, the composition is irradiated with light to obtain a photocured product. Therefore, the substituents of the cycloalkyl group, aryl group, and heterocyclic residue of R ^{8 to} R ¹⁰ do not include a linked ring structure.

The halogen atoms of R ^{5 to} R ⁷ are fluorine atoms, chlorine atoms, bromine atoms, etc., and the linear alkyl groups are those having 1 to 13 carbon atoms, and branched alkyls. Examples of the group include those having 3 to 13 carbon atoms, and examples of the substituent of the aryl group which may have a substituent include a linear alkyl group having 1 to 13 carbon atoms and 3 carbon atoms. A branched alkyl group of ˜13 or a cycloalkyl group having a linear alkyl group of 1 to 13 carbon atoms as a substituent, or a linear alkyl group of R ⁹ of —SR ⁹ , a branched chain Of the alkyl group, the substituent of the cycloalkyl group which may have a substituent, the substituent of the aryl group which may have a substituent, and the heterocyclic residue which may have a substituent is then the substituents and heterocyclic residue, is the same as described above, also, the -COYR ¹¹ There linear alkyl group R ⁸ when it is -NR ^8, branched alkyl group, which may have a substituent group substituents of the cycloalkyl group, an aryl group which may have a substituent And a heterocyclic residue which may have a substituent and the substituent thereof are the same as those described above, and Y in -COYR ^{11 represents} an oxygen atom or The linear alkyl group for R ¹¹ when it is a sulfur atom has 1 to 13 carbon atoms, and the branched alkyl group has 3 to 13 carbon atoms. Examples of the substituent of the cycloalkyl group which may have a group include a linear alkyl group having 1 to 13 carbon atoms, a branched alkyl group having 3 to 13 carbon atoms, and the like. As a substituent of the aralkyl group which may have a linear alkyl having 1 to 13 carbon atoms Or a branched alkyl group having 3 to 13 carbon atoms, or a substituent of the aryl group which may have a substituent, is a linear alkyl group having 1 to 13 carbon atoms, carbon A branched alkyl group having 3 to 13 carbon atoms, or a cycloalkyl group having a linear alkyl group having 1 to 13 carbon atoms as a substituent, and the heterocyclic residue optionally having a substituent The heterocyclic residue of the group is a pyridyl group or the like, and the substituent is a linear alkyl group having 1 to 13 carbon atoms, a branched alkyl group having 3 to 13 carbon atoms, or a carbon number. Examples thereof include cycloalkyl groups having 1 to 13 linear alkyl groups as substituents.

In the general formula I), when one of R ^{1 to} R ⁴ is —NH ₂ , if all of R ^{5 to} R ⁷ are hydrogen atoms, it is difficult to adjust the color tone as a pigment. ^{When one of 1 to} R ⁴ is —NH ₂ , at least one of R ^{5 to} R ⁷ is not a hydrogen atom. In addition, when R ^{5 to} R ⁷ have a linked ring structure of 3 or more rings, when the composition is irradiated with light to form a photocured product, the linked ring structure portion is cleaved and no color is exhibited. ^{5 to} R ⁷ do not have a linked ring structure of three or more rings.

  Among the anthraquinone dyes represented by the general formula (II), preferable yellow dyes include those represented by the following general formula (IIa).

[In Formula (IIa), R ¹² represents a linear or branched alkyl group having 1 to 5 carbon atoms, or a cycloalkyl group having a linear alkyl group having 1 to 6 carbon atoms as a substituent. R ³ _a , R ⁴ _a , R ⁵ _a , R ⁶ _a , and R ⁷ _a are each independently a hydrogen atom, a linear alkyl group having 1 to 5 carbon atoms, or 1 to 6 carbon atoms. A phenylthio group, a pyridylthio group, or a cyclohexyl carboxyl group having a linear alkyl group having 1 to 6 carbon atoms as a substituent. . ]

  Specific examples of preferable yellow pigments represented by the general formula (IIa) include the following.

  In the anthraquinone dyes represented by the general formula (II), examples of suitable red dyes include those represented by the following general formula (IIb).

[In the formula (IIb), R ² _b is a hydrogen atom, a hydroxyl group, a phenylthio group having a linear or branched alkyl group having 1 to 8 carbon atoms as a substituent, or a carbon atom having 1 to 8 carbon atoms. A phenylthio group having a cyclohexyl group as a substituent having a linear alkyl group as a substituent, and R ⁵ _b is a carboxyl group having a linear or branched alkyl group having 1 to 8 carbon atoms as a substituent. A cyclohexyl carboxyl group having a linear alkyl group having 1 to 8 carbon atoms as a substituent, a phenyl carboxyl group having a linear alkyl group having 1 to 8 carbon atoms as a substituent, or a carbon number of 1 to 8 a phenoxy group having a straight chain alkyl group as a substituent of, R ⁷ _b is carboxy with a hydrogen atom, a linear or branched alkyl group having 1 to 8 carbon atoms as a substituent Silyl group, a cyclohexyl carboxyl group having a linear alkyl group having 1 to 8 carbon atoms as a substituent, a phenyl carboxyl group having a linear alkyl group having 1 to 8 carbon atoms as a substituent, or a carbon number of 1 The phenyl carboxyl group which has a cyclohexyl group which has a linear alkyl group of -8 as a substituent is shown. ]

  In the anthraquinone dyes represented by the general formula (II), examples of suitable red dyes include those represented by the following general formula (IIc).

[In Formula (IIc), R ¹³ represents a cyclohexyl group having a linear or branched alkyl group having 1 to 8 carbon atoms or a linear alkyl group having 1 to 8 carbon atoms as a substituent. , R ¹⁴ represents a phenyl group having a linear alkyl group having 1 to 8 carbon atoms as a substituent. ]

  Specific examples of suitable red dyes represented by the general formulas (IIb) and (IIc) include the following.

  Among the anthraquinone dyes represented by the general formula II), preferable blue dyes include those represented by the following general formula (IId).

[In the formula (IId), R ² _d is a linear alkylthio group having 1 to 8 carbon atoms, a phenylamide group having a linear alkyl group having 1 to 8 carbon atoms as a substituent, or a carbon number 1 to 8 represents a phenylthio group having a linear alkyl group as a substituent, and R ³ _d , R ⁴ _d , and R ⁷ _d are each independently a hydrogen atom, a hydroxyl group, or a carbon number of 1 to 13 A phenylthio group having a linear or branched alkyl group as a substituent, R ⁵ _d is a hydrogen atom, a carboxyl group having a linear or branched alkyl group having 1 to 8 carbon atoms as a substituent , A cyclohexyl carboxyl group having a linear alkyl group having 1 to 8 carbon atoms as a substituent, or a phenyl carboxyl group having a linear alkyl group having 1 to 8 carbon atoms as a substituent, R ¹⁵ is Hydrogen atom or Represents a linear or branched alkyl group having 1 to 8 carbon atoms or a phenyl group having a fluorine atom or a chlorine atom as a substituent. ]

  Specific examples of suitable blue dyes represented by the general formula (IId) include the following.

  The anthraquinone dye represented by the general formula (II) is synthesized by combining conventionally known methods described in, for example, JP-A-56-55479 and JP-A-58-53954. be able to.

  The solubility of the anthraquinone dye in the liquid crystal according to the present invention is defined as a value obtained by adding the dye to the liquid crystal, shaking it for 1 hour, leaving it overnight, and measuring the dye concentration in the liquid crystal after filtration. The amount is preferably 0.5 to 10% by weight, particularly preferably 0.5 to 6% by weight. If the solubility of the dye in the liquid crystal is lower than this range, a sufficient effect of adding the dye cannot be obtained. On the other hand, if the solubility is higher than this range, the composition is irradiated with light to obtain a cured product. It tends to inhibit polymerization.

I-4. (D) Photopolymerization initiator component The light control liquid crystal composition of the present invention further comprises (D) a photopolymerization initiator component. In the present invention, the photopolymerization initiator is preferably an acylphosphine oxide photopolymerization initiator. Specifically, for example, 2,4,6-trimethylbenzoyldiphenylphosphine oxide such as “Lucirin TPO” manufactured by BASF Etc.

I-5. (A)-(D) Component Mixing Ratio The present invention contains the (A) liquid crystal component, the (B) photocurable compound component, the (C) dye component, and the (D) photopolymerization initiator component. In the light control liquid crystal composition, the pigment component is preferably 0.5 to 5 parts by weight with respect to 100 parts by weight of the liquid crystal component, and the liquid crystal component to which the pigment component is added and the photocurable compound component The ratio of is preferably 90:10 to 50:50 by weight, and particularly preferably 80:20 to 50:50. If the ratio of the photocurable compound component is less than this range, the liquid crystal component becomes excessive and the compatibility with the photocurable compound component decreases, and both tend to separate before curing by light irradiation, When the ratio of the photocurable compound component is beyond this range, the light shielding property as a cured product tends to be lowered. In addition, it is preferable that the ratio of a photoinitiator component is about 0.1-5 weight part with respect to 100 weight part of photocurable compound components.

I-6. Other Components In addition, in the light control liquid crystal composition of the present invention, in addition to the components (A) to (D), for example, benzotriazole-based, benzophenone-based, hindered amine-based light stabilizers, phosphite-based, Antioxidants such as hindered phenols, thermal polymerization inhibitors, thiol compounds, photosensitizers, photosensitizers, chain transfer inhibitors, polymerization inhibitors, adhesion promoters, antifoaming agents, crosslinking agents, interfaces An activator, a thermosetting accelerator, a thermoplastic resin, a thermosetting resin, a thickener such as urethane diacrylate, and the like may be contained. Moreover, in order to control the cell gap as a light control element, you may add spherical or cylindrical spacers, such as a silica, glass, a plastic, a ceramic. The cell gap at this time can be set in the range of 2 to 100 μm.

II. Photocured product of light control liquid crystal composition In the present invention, a photocured product is obtained by photoirradiating the photocurable compound by light irradiation of the light control liquid crystal composition. Examples of the light irradiation light source at that time include a high-pressure mercury lamp, a metal halide lamp, a xenon lamp, and a halogen lamp that can be irradiated with ultraviolet rays. Further, the curing temperature is preferably a temperature at which the liquid crystal composition can be kept in a uniform state, that is, a temperature higher than the phase separation temperature, and preferably 1 to 5 ° C. higher than the phase separation temperature. If the temperature is lower than this temperature, the liquid crystal and the photocurable compound are separated before polymerization, and thus a uniform polymer tends to be hardly obtained. On the other hand, if the temperature is higher than this temperature, the polymer and the liquid crystal obtained by photocuring are likely to be obtained. When these are separated, the domain size of the liquid crystal tends to be small.

III. Light control element III-1. Structure of the light control device The light control device of the present invention has a photocured product layer of the liquid crystal composition for light control sandwiched between a pair of substrates in which at least one substrate is a transparent substrate having a transparent electrode. It has been made. Here, examples of the substrate include inorganic transparent materials such as glass and quartz, colorless transparent or colored transparent or opaque materials such as metals, metal oxides, semiconductors, ceramics, plastic plates, and plastic films, and electrodes. Is formed on the substrate by, for example, a thin film such as a metal oxide, metal, semiconductor, organic conductive material or the like entirely or partially by a known coating method, printing method, sputtering method or other vapor deposition method. It is. Alternatively, it may be partially etched after forming a conductive thin film. In particular, in order to obtain a light control device with a large area, from the viewpoint of productivity and workability, an ITO (indium oxide, tin oxide) electrode is deposited on a transparent polymer film such as PET by a vapor deposition method such as sputtering or a printing method. It is desirable to use the electrode substrate formed by using. A wiring for connecting the electrodes or connecting the electrodes and the outside may be provided on the substrate. For example, a segment driving electrode substrate, a matrix driving electrode substrate, an active matrix driving electrode substrate, or the like may be used. Furthermore, the electrode surface provided on the substrate is a protective film or alignment film made of an organic compound such as polyimide, polyamide, silicon, and cyanide, an inorganic compound such as SiO ₂ , TiO ₂ , and ZrO ₂ , or a mixture thereof. The entire surface or a part thereof may be covered.

  When a plastic film is used as the substrate, a flexible and lightweight dimmer element can be obtained. For this reason, it is sandwiched between a pair of flat or curved glass or hard plastic via an adhesive layer such as polyvinyl butyral, vinyl acetate, double-sided tape, adhesive, etc. It can be used by attaching it to a surface of glass-like glass or hard plastic with a double-sided tape or an adhesive. Further, it may be sandwiched between soft plastics or attached to one side or both sides. In addition, a protective layer such as a hard coat, an ultraviolet cut layer, an infrared cut layer, or a half mirror may be provided on the substrate surface opposite to the electrode surface of the light control element, or a color filter may be laminated or polarized light. A child filter may be attached. In addition, a color plate may be placed on the rear side of the light control element. Furthermore, the light control element can be used after being cut into a desired size and shape. Moreover, you may laminate | stack with an electroluminescent display element, a light emitting diode display element, an electrochromic display element, and another liquid crystal display element.

  In addition, since the light control element in this invention contains the dichroic dye in photocured material, a colored liquid crystal etc. ooze out from the end surface of this light control element, and there exists a possibility of stain | polishing the periphery. In order to prevent this, the end face of the light control element is a tape such as an adhesive tape, a thermocompression bonding tape, a thermosetting tape, and / or a thermosetting resin, a photocurable resin, a moisture curable resin, a room temperature curable type. By protecting the periphery with curable resins and thermoplastic resins such as adhesives, anaerobic adhesives, silicone adhesives, fluororesin adhesives, polyester adhesives, and vinyl chloride adhesives It is possible to prevent contamination. In addition, this protection may have a function of preventing deterioration of the light control element. In this case, the end face may be protected by covering the entire end face or by pouring a curable resin or thermoplastic resin from the end face into the light control element and solidifying it. May be covered with tape.

III-2. Characteristics of light control element III-2-1. Color Tone The light control device of the present invention not only provides a yellow to blue light control device by using a dichroic dye, but also has various color tones such as brown, gray, and black by mixing the dye. An optical element is obtained.

III-2-2. Haze It is preferable that the haze at the time of voltage OFF of the light control element of this invention is 30-100. If it is less than this range, the degree of obstructing the field of view becomes worse. Further, the haze when the voltage is ON is preferably 10 or less. If it is less than 10, the field of view becomes cloudy. . The haze is obtained by measuring the light control element in the voltage ON and OFF states with a haze meter.

III-2-3. Display temperature range It is preferable that the display temperature range of the light control element of this invention is 10-100 degreeC. If the temperature is lower than 10 ° C., the response speed of the liquid crystal becomes slow. On the other hand, if it exceeds 100 ° C., the phase transition temperature of the liquid crystal to be used is exceeded, and the liquid crystal device does not function.

III-2-4. Driving voltage A driving device for applying a voltage to the light control element of the present invention is a device that can apply a DC voltage of 2 to 50 V or an AC voltage of 10 to 10000 Hz. Any device that opens or short-circuits may be used. The driving device may be provided with a voltage application circuit for segment driving, a voltage application circuit for matrix driving, a voltage application circuit for active matrix, and the like. Furthermore, seed sensors such as an infrared sensor, a sound sensor, a pressure sensor, a heat sensor, a gas sensor, an optical sensor, a humidity sensor, and a radiation sensor may be provided.

Example 1
(A) As a liquid crystal component, 73.7 parts by weight of fluorine-containing and / or chlorine-containing nematic liquid crystal (“MLC2058” manufactured by Merck) having a phase transition temperature (Tni) of 106.4 ° C., (B) photocurability As compound components, 2-ethylhexyl acrylate (manufactured by Aldrich) 15.9 parts by weight and 1,6-hexanediol diacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd.) 7.96 parts by weight, and (C) a dye component having the following structure: 2.3 parts by weight of blue dye (B1) and 0.14 parts by weight of (4) 2,4,6-trimethylbenzoyldiphenylphosphine oxide ("Lucirin TPO" manufactured by BASF) as a photopolymerization initiator component at room temperature By mixing, a liquid crystal composition for light control was prepared. About the obtained liquid crystal composition for light control, the phase-separation temperature was measured with the method shown below, and the result was shown in Table 1.
<Phase separation temperature>
A liquid crystal composition for light control is dropped on a preparation, covered with a cover glass, set on a hot stage with a microscope temperature controller ("FP-80" manufactured by METTLER) at 40 ° C, and two polarizing plates are obtained with a polarizing microscope. In crossed Nicol state, confirm that it is a dark field (isotropic state) before observation, observe with a polarizing microscope while cooling at 1 ° C / min, and the temperature at which a small bright field began to be observed in the observation field Was the phase separation temperature.

Subsequently, the obtained liquid crystal composition for dimming was injected into two 2 cm square ITO glass plates that had been shifted by 5 mm with a 10 μm gap, and the light intensity at 365 nm was 17 mJ using a metal halide lamp manufactured by Ushio. A sample is set on a thermoplate manufactured by AS ONE so that the sample temperature can be maintained at 22 ° C. at a position where it becomes / cm ^2, and the photocurable compound component is photocured by irradiating with light for 2 minutes. Obtained. About the obtained light control element, the haze at the time of a voltage non-application state and a drive, a drive voltage, and an operating temperature range were measured with the method shown below, and the result was shown in Table 1.

<Haze>
Measurement was performed using a haze meter manufactured by Toyo Seiki Co., Ltd., when no voltage was applied and when 14 V was applied by applying a sine wave of 50 Hz.
<Drive voltage>
Set the light control element sample in the spectrophotometer, measure the light transmittance while changing the applied voltage, and set the light transmittance to 100% when the light transmittance hardly increases even when the applied voltage is increased. The applied voltage at which the light transmittance is 90% was used as the drive voltage (V ₉₀ ).
<Operating temperature range>
The fiber type spectroscope “USB2000” is set in the environmental tester “SH641” manufactured by ESPEC Co., Ltd., and the light transmittance (T ₀ ;%) and the driving voltage (V ₉₀ ) when the applied voltage is 0 V while changing the temperature condition. ) light transmittance upon application of a _(T 90; measured%) was the temperature difference between _{T 0} and _{T 90} have 10% and operating temperature range.

Example 2
In Example 1, (C) 15.9 parts by weight of 2-ethylhexyl acrylate as a photocurable compound component was changed to 15.9 parts by weight of hexyl acrylate (manufactured by Tokyo Chemical Industry Co., Ltd.), and (C) as a dye component A dimming liquid crystal composition was prepared in the same manner as in Example 1 except that 2.3 parts by weight of the blue dye (B2) having the following structure was used, and the phase separation temperature was measured in the same manner as described above. Further, photocuring to obtain a blue dimming element, and for the obtained dimming element, in the same manner as described above, the haze, driving voltage, and operating temperature range during no voltage application and driving are measured. The results are shown in Table 1.

Example 3
(A) 67.2 parts by weight of “MLC2058” manufactured by Merck as a liquid crystal component, 15.8 parts by weight of hexyl acrylate as a (B) photocurable compound component, and 7,6-hexanediol diacrylate. 65 parts by weight, (C) As a dye component, 4.07 parts by weight of the blue dye (B2) having the above structure, 2.2 parts by weight of the red dye (R1) having the following structure, and a yellow dye (Y1) having the following structure 1.42 parts by weight, 0.72 parts by weight of yellow dye (Y2) having the following structure, and (D) 0.5 parts by weight of “Lucirin TPO” manufactured by BASF as a photopolymerization initiator component, A liquid crystal composition for light control was prepared in the same manner as in Example 1, the phase separation temperature was measured by the same method as described above, and further photocured to obtain a blue light control device, and the light control device obtained In the same manner as described above, no voltage application state and Haze at the time of moving, and measuring the driving voltage, and operating temperature range, the results are shown in Table 1.

Example 4
(A) 73.3 parts by weight of “MLC2058” manufactured by Merck as a liquid crystal component, 15.8 parts by weight of hexyl acrylate as a (B) photocurable compound component, and 7.6- 1,6-hexanediol diacrylate. 65 parts by weight, (C) 2.29 parts by weight of the blue dye (B1) having the above structure as a dye component, and (D) 0.14 parts by weight of “Lucirin TPO” manufactured by BASF as a photopolymerization initiator component A liquid crystal composition for light control was prepared in the same manner as in Example 1 except that the phase separation temperature was measured in the same manner as described above for the obtained liquid crystal composition for light control, and the results were shown. It was shown in 1. Subsequently, the obtained liquid crystal composition for light control was applied on a 5 cm square ITO-PET using an applicator, and the composition surface was overlaid so that the surface of the ITO electrode was an ITO electrode surface. The sample is set on an ASONE thermoplate so that the sample temperature can be maintained at 22 ° C. at a position where the light intensity at 365 nm is 17 mJ / cm ^2, and the photocurable compound component is photocured by light irradiation for 2 minutes. Thus, a blue light control element was obtained. About the obtained light control element, the haze at the time of a voltage non-application state and a drive, a drive voltage, and an operating temperature range were measured by the method similar to the above, and the result was shown in Table 1.

Comparative Example 1
In Example 1, (A) Merck “MLC2058” as the liquid crystal component) is a nematic liquid crystal (“BDH-” manufactured by Merck Ltd.) having a phase transition temperature (Tni) of 70.3 ° C. and containing no fluorine or chlorine. Except for the change to E8), a liquid crystal composition for dimming was prepared in the same manner as in Example 1, and the phase separation temperature was measured and photocured in the same manner as described above to obtain a blue dimming element. With respect to the obtained light control device, the voltage non-application state and the haze at the time of driving, the driving voltage, and the operating temperature range were measured by the same method as described above, and the results are shown in Table 1.

  The light control element obtained by the liquid crystal composition for light control of the present invention includes a window, a partition, a door, a building material such as a stained glass, a vehicle material such as a window and a sunroof, a display for displaying a picture, characters, numbers, and the like. It can be used for display materials such as show windows and showcases, ornaments that are combined and cut out in various shapes such as flowers and butterflies, and event equipment that aims for a light-up effect. Can be attached.

Claims (6)

A light control liquid crystal composition comprising the following component (A), component (B), component (C), and component (D):
Component (A): Liquid crystal component containing fluorine-containing and / or chlorine-containing nematic liquid crystal having a phase transition temperature (Tni) of 100 ° C. or higher (B) Component: linear or branched chain having 5 to 13 carbon atoms A photocurable compound component comprising a mono (meth) acrylate (B-1) component having an alkyl group and a di (meth) acrylate (B-2) component represented by the following general formula (I)

CH ₂ ═CH—C—O—X—O—C—CH═CH ₂ (I)
‖ ‖
O O

[In formula (I), X represents a linear alkylene group having 4 to 13 carbon atoms. ]
Component (C): a dye component containing an anthraquinone dye represented by the following general formula (II) and having four or less aromatic rings

[In the formula (II), R ¹ is —NHR ⁸ (R ⁸ is a hydrogen atom, a linear or branched alkyl group, an optionally substituted cycloalkyl group, or a substituent. An aryl group which may be substituted, or a heterocyclic residue which may have a substituent.), Or -SR ⁹ (R ⁹ is a linear or branched alkyl group or a substituent. A cycloalkyl group that may be substituted, an aryl group that may have a substituent, or a heterocyclic residue that may have a substituent.
R ² , R ³ , and R ⁴ are each independently a hydrogen atom, —NHR ⁸ (R ⁸ is as defined above), —SR ⁹ (R ⁹ is as defined above), or — OR ¹⁰ (R ¹⁰ has a hydrogen atom, a linear or branched alkyl group, a cycloalkyl group which may have a substituent, an aryl group which may have a substituent, or a substituent. A heterocyclic residue that may be present). However, when ^one of R ^{1 to} R ⁴ is —NH ₂ , the other three are not —NH ₂ . Further, a cycloalkyl group, an aryl group, and a substituent having a heterocyclic residue of R ⁸ to R ¹⁰ does not include a coupling ring.
R ⁵ , R ⁶ , and R ⁷ each independently have a hydrogen atom, a halogen atom, a linear or branched alkyl group, an aryl group that may have a substituent, or a substituent. An aryloxy group, —SR ⁹ (R ⁹ is as defined above), or —COYR ¹¹ (Y is an oxygen atom, sulfur atom, or —NR ⁸ (R ⁸ is as defined above). R ¹¹ represents a linear or branched alkyl group, a cycloalkyl group which may have a substituent, an aralkyl group which may have a substituent, or a substituent. It represents a good aryl group or a heterocyclic residue which may have a substituent. However, when ^one of R ^{1 to} R ⁴ is —NH ₂ , at least one of R ^{5 to} R ⁷ is not a hydrogen atom. R ^{5 to} R ⁷ do not have three or more linked ring structures. ]
(D) component; photopolymerization initiator component   A photocured product of a liquid crystal composition for light control, wherein the photocurable compound component of the component (B) of the liquid crystal composition for light control according to claim 1 is photocured.   The photocured product layer of the liquid crystal composition for light control according to claim 2 is sandwiched between a pair of substrates facing each other, at least one of which is a transparent substrate having a transparent electrode. Dimmer element.   The light control device according to claim 3, wherein both of the pair of substrates are transparent substrates having transparent electrodes.   The light control device according to claim 4, which is for automobiles.   The light control element according to claim 4, which is for building materials.