JPH05173114A - Light control element - Google Patents

Abstract

PURPOSE:To obtain the useful liquid crystal element which has high visibility and is wide in utilization range as the light of the wavelength corresponding to the color of a reflection surface is absorbed when a liquid crystal layer is opaque by forming the light control element having a specific UV absorption layer. CONSTITUTION:A light control material consisting of a liquid crystal for controlling the transmission and scattering of the light by the presence or absence of the impression of an electric field and a high polymer holding this liquid crystal is clamped between a pair of electrode substrates having electrodes on the inside surfaces. The light control element has the UV ray absorption layer having <=30% transmittance of 380nm light and >=90% transmittance of 440nm light. The light control material contains dichromatic dyestuff. The liquid crystal to be used is selected from a group consisting of a nematic liquid crystal, smectic liquid crystal and cholesteric liquid crystal. On the other hand, the high polymer holding these liquid crystals is exemplified by, for example, polyethylene, polyacrylic acid, etc.

Description

Detailed Description of the Invention

[0001]

2. Description of the Related Art A light control material composed of liquid crystal and a polymer holding it is in a cloudy state because the incident light is scattered due to the difference between the refractive index of the polymer and the refractive index of the liquid crystal when no electric field is applied. Also, when an electric field is applied, the liquid crystal aligns in the direction of the electric field, and the refractive index of the polymer and the refractive index of the liquid crystal are close to each other, which causes a reversible phenomenon of becoming transparent. Wake up.

Conventionally, dimming elements utilizing such properties are disclosed in, for example, Japanese Patent Publication No. 58-501631, Japanese Patent Publication No. 63-5.
No. 01512, JP-A-63-271233 and the like.

[0003]

The dimming element has a large transmittance change, repeated response, response speed, voltage sensitivity,
Durability (light resistance, heat resistance, water resistance, etc.) is required, but the conventional light control element cannot be said to have characteristics that can satisfy these requirements. In particular, when a color dimming device is prepared by containing a dye such as a dichroic dye, the dye is faded or discolored by light, which causes a problem in light resistance.

[0004]

The present invention is to solve the above problems. That is, according to the present invention, a dimming element in which a dimming material composed of a liquid crystal that controls transmission and scattering of light depending on whether an electric field is applied and a polymer that holds the liquid crystal is sandwiched between a pair of electrode substrates having electrodes on its inner surface is 380 nm. The light transmittance of 30% or less and the light transmittance of 440 nm is 90% or less.
The gist of the present invention is a light control element having an ultraviolet absorption layer of not less than 10%, and a light control element characterized in that the light control material contains a dichroic dye.

The present invention will be described in detail below. The light control material containing the liquid crystal and the polymer of the present invention can be produced, for example, by the following methods (a) to (d), and together with the liquid crystal and / or the polymer in an appropriate step of the production process. , Blend a prescribed dye. (A) An impregnation method of impregnating a polymer porous body with liquid crystal. (B) An emulsification method in which a liquid crystal is emulsified into fine droplets in an aqueous solution of a water-soluble polymer and then cast on a substrate having a transparent electrode. (C) A solvent casting method in which a liquid crystal and a polymer are dissolved in their common solvent and then cast. (D) A liquid in which a uniform solution of a liquid crystal and a prepolymer of a polymer that holds the liquid crystal (a generic name for substances (eg, monomers) before being polymerized) is prepared, and this is subjected to phase separation by polymerization to form a phase-separated structure. legal.

The proportion of the liquid crystal in the light control material thus obtained is preferably 5 to 95% by weight,
The content is more preferably 40 to 95% by weight, and the liquid crystal used may be one selected from the group consisting of nematic liquid crystal, smectic liquid crystal and cholesteric liquid crystal, or a mixture thereof. On the other hand, as the polymer holding these liquid crystals, specifically, polyethylene, polyacrylic acid, polyacrylic acid ester, polyvinyl acetate, polyacrylonitrile, polyvinyl chloride, addition polymers of vinyl compounds such as polyvinyl fluoride, Polymethacrylic acid, polymethacrylic acid ester, polyvinylidene chloride,
Polyvinylidene fluoride, vinylidene cyanide, vinylidene fluoride / trifluoroethylene copolymer, vinylidene fluoride / tetrafluoroethylene copolymer, vinylidene cyanide / vinyl acetate copolymer, etc. Polymer of vinylidene compound or fluorinated compound or Copolymers, fluorine-containing compounds such as polytrifluoroethylene, polytetrafluoroethylene, polyhexafluoropropylene, polyamides such as nylon 6, nylon 66, polyimides, polyurethanes, polypeptides, polyesters such as polyethylene terephthalate, polycarbonates, polyoxymethylene,
Examples thereof include polyethers such as polyethylene oxide and polypropylene oxide, epoxy resins, polyvinyl alcohol, polyvinyl butyral and the like. These polymers are 1
The seeds may be used alone or in combination of two or more kinds.

If necessary, stabilizers such as surfactants and antioxidants, chain transfer agents, photosensitizers and crosslinking agents may be added to the light control material according to the present invention. it can. The light control element of the present invention uses such a light control material, and sandwiches it between a pair of electrode substrates having an electrode, preferably a transparent electrode on the inner surface, and further has a light transmittance of 380 nm of 3
It is manufactured by applying an ultraviolet absorbing layer having a transmittance of 440 nm of 90% or more and 0% or less.

This ultraviolet absorbing layer may be used as an ultraviolet absorbing layer by dissolving an ultraviolet absorbing agent in a light control material composed of a liquid crystal and a polymer, or an ultraviolet absorbing layer may be laminated inside or outside at least one of the electrodes. You may. As a method for laminating this ultraviolet absorbing layer, a method in which an ultraviolet absorbent is mixed with transparent resin pellets and melt-molded to form a film, which is attached to the inside or outside of the electrode, the ultraviolet absorbent and a solvent together with the transparent resin are used. There is a method in which it is dissolved in the solution and applied to the inner or outer surface of the electrode.

As the ultraviolet absorber, a benzophenone type such as 2,4-dihydroxybenzophenone, 2- (2 ')
-Hydroxy-5'-methylphenyl) benzotriazole type, salicylic acid type such as p-octylphenyl saltylate, and the like having a known UV cut function can be used. These can be used alone or in combination as appropriate to produce the desired filter.

As the resin used in the ultraviolet absorbing layer, acrylic resin, urethane resin, styrene resin, polyester resin, vinyl acetate resin, acetal resin or their copolymers can be used. Examples of commercially available products include SC-3 from Fuji Photo Film Co., Ltd.
Ultraviolet absorption filters sold under the trade names of 9, SC-40 and SC-41 can be preferably used. 44
In the case of an ultraviolet absorption filter having a transmittance of 0 nm light of less than 90%, the filter is colored yellow, which is not preferable for use in a light control element. Further, when the transmittance of 380 nm light exceeds 30%, the effect of improving the light resistance is small. Examples of the dichroic dye added to the light control material include anthraquinone dyes, quinophthalone dyes and azo dyes, and anthraquinone dyes or quinophthalone dyes having good light resistance are more preferable.

Examples of the anthraquinone dyes include dyes represented by the following general formulas [I] and [II].

[0012]

[Chemical 1]

{Wherein R¹Is an optionally substituted amino
Group, hydroxyl group or -SR ⁹(R⁹Is replaced
It represents an optionally substituted aryl group or heterocyclic residue. )
Indicates R², R³, R^FourAre independent hydrogen
Child, hydroxyl group, optionally substituted amino group,
Alkylthio group, -SR⁹Indicates R^Five, R⁶, R⁷
Are each independently a hydrogen atom, halogen atom or
Optionally substituted alkyl group, optionally substituted aryl
Group, optionally substituted phenyl group, -S-
R⁹, -COXR^Ten(X is -O-, -S- or -NH
-Indicates R^TenIs an optionally substituted alkyl group,
Optionally substituted aryl group, optionally substituted
Aralkyl group or optionally substituted cycloalkyl
Represents a radical. ), A cyano group, and Y and Z are respectively
Independently oxygen atom, sulfur atom or = NR¹¹(R¹¹Is water
Indicates an elementary atom or an optionally substituted alkyl group.
You ), And R⁸Is a hydrogen atom, which may be substituted
Alkyl group, optionally substituted cycloalkyl group
Or an aryl group which may be substituted. } More preferred dyes are those represented by the following general formula [III]
Examples include anthraquinone dyes represented by [VIII]
It

[0014]

[Chemical 2]

(R ¹⁴ represents a hydrogen atom, an alkyl group having 1 to 8 carbon atoms or an alkoxy group having 1 to 8 carbon atoms).

[0016]

[Chemical 3]

And R ¹⁵ and R ¹⁸ have the same meanings as R ¹⁴ in the general formula [III]. ) Is shown. ]

[0018]

[Chemical 4]

(R ²¹ is R ¹⁴ in the general formula [III] above.
Has the same meaning as. ) Is shown. )

[0020]

[Chemical 5]

(In the formula, R ²² has the same meaning as R ¹⁴ in the above general formula [III], X represents an oxygen atom, a sulfur atom or a direct bond, and Z represents a hydroxyl group or an amino group.)

[0022]

[Chemical 6]

(R ²⁴ is R ¹⁴ in the general formula [III] above.
Has the same meaning as. ) And Y represents an oxygen atom or an imino group. )

[0024]

[Chemical 7]

Examples of the quinophthalone dye include dyes represented by the following general formula [IX].

[0026]

[Chemical 8]

However, R ³⁴ has the same meaning as R ¹⁴ in the above formula [III]. )) Examples of the azo dye include dyes represented by the following general formula [X].

[0028]

[Chemical 9]

[In the formula, -X-, -Y-, and -Z- are 1,4 optionally substituted with a halogen atom or a methyl group.
-Phenylene, 1,4-naphthylene, 5,6,7,8-
Tetrahydro-1,4 indicates naphthylene or 5,8-quinolylene, R ³⁵ is a hydrogen atom, -R ^37, -SO ₂ R ³⁷
(R ³⁷ represents an alkyl group having 1 to 18 carbon atoms which may be substituted with an alkoxy group having 1 to 10 carbon atoms.)

[0030]

[Chemical 10]

(R ³⁸ is -R ³⁷ ; R ³⁷ , OR ³⁷ or a phenyl group which may be substituted with a halogen atom;
³⁷ represents a cyclohexyl group which may be substituted with ³⁷ ,
Represents 0 or 1. ) Or a halogen atom, R
³⁶ is

[0032]

[Chemical 11]

[0033] (R ^39, R ⁴⁰ represents a hydrogen atom, an -CH ₂ R ^38, or alternatively to each other, may form a nitrogen-containing heterocyclic ring linked to a -Z-, the R ^39, R ⁴⁰ At least one represents a group other than a hydrogen atom), and m represents 1 or 2. However, when R ³⁵ is a hydrogen atom and m is 1, R ³⁶
Represents a -N (CH _{3) 2} group other than. The above dichroic dyes may be used alone or in appropriate combination. The ratio of the dichroic dye to the liquid crystal may be any ratio as long as it is dissolved, but it is used in the range of 0.01 to 20% by weight with respect to the liquid crystal, and more preferably 0.1. It is used in the range of 10 to 10% by weight.

A transparent electrode such as ITO is used as the electrode, and a transparent substrate such as a glass or plastic plate such as polyester is used as the electrode substrate. When a pair of transparent electrode substrates is used, it can be used as a transmissive dimming element, and when one is transparent and the other is opaque, a reflective layer is placed after the opaque electrode substrate. Therefore, it can be used as a reflection type light control device. The light control element according to the present invention includes a display device, a light control window,
It can be used for devices such as mirrors, sunglasses, and memories that utilize light transmission or reflection.

[0035]

EXAMPLES The present invention will now be specifically described with reference to examples, but the present invention is not limited to the following examples. As an evaluation method of the light control element of the present invention in Examples, before and after irradiating the light control element with light using a xenon fade meter (FAL-25AX-HC / B / EC type manufactured by Suga Test Instruments Co., Ltd.) for a certain period of time. Color difference (ΔE; measured by the method described in JIS Z8730).

Example 1 An ITO film having a thickness of 250 Å was formed by sputtering on a polyethylene terephthalate film having a thickness of 125 μm to prepare a transparent electrode plate.

Separately, 1.0 g of trimethylolpropane triacrylate, 2.0 g of n-butyl acrylate and 7.0 of biphenyl nematic liquid crystal E-8 (manufactured by BDH).
g, 0.02 g of 2,2-dimethoxy-2-phenylacetophenone, which is a polymerization initiator, and 0.075 g of 1- [4- (4-butylcyclohexyl) phenylthio] -5- (2-pyridylthio) anthraquinone, 4-butyl. Cyclohexyl 5-amino-6- (4-butylphenoxy)
-8-Hydroxy-2-anthraquinonecarboxylate 0.049 g, 4-butylcyclohexyl 1,4-diamino-2-anthraquinonecarboxylate 0.02
5 g and 4-butylcyclohexyl 1-amino-4-
A black dichroic dye mixture consisting of 0.037 g of (4-butylanilino) -2-anthraquinonecarboxylate was added and dissolved, and a plastic spacer (divinylbenzene copolymer) spacer having a diameter of 10 μm was added to the solution. 15 g was added to make a mixed solution.

This mixed solution is inserted between the two transparent electrode plates prepared above (the ITO film side is placed inside),
By exposing with a UV irradiation device, a uniform light control element without cracks or the like was obtained. The energy given is 800
Corresponds to mJ. An ultraviolet absorption filter SC-40 (Fuji Photo Film Co., Ltd.) is provided on one surface of this light control element.
The transmittance of light having a wavelength of 380 nm is 1%, and the transmittance of light having a wavelength of 440 nm is 92%).

Use a xenon fade meter to measure 1
A light resistance test was conducted by irradiating light for 00 hours. The color difference (ΔE) after the light resistance test and before the test was 1.5, and the light resistance was good. In addition, the parallel light transmittance of this element when a voltage is not applied is 6.8%, which is 100 V AC (6
0 Hz, sine wave) is 72.4% when applied,
Each did not change before and after the light resistance test.

Comparative Example 1 In Example 1, SC-38 (Fuji Photo Film Co., Ltd.) was used instead of the dimmer element (a) and the ultraviolet absorption filter SC-40 which were treated in the same manner except that the ultraviolet absorption filter was not used. ), The transmittance of 380 nm light is 42%, 4
A light control element (b) having a 40 nm light transmittance of 93% attached was prepared, and the same light resistance test as in Example 1 was conducted.
In the light control elements (a) and (b), ΔE is 2
The values were 1.1 and 18.0, which were inferior to those in Example 1.

Example 2 Instead of the black dichroic dye mixture of Example 1, 1- [4-
(4-Butylcyclohexyl) phenylthio] -5-
0.1 g of (2-pyridylthio) anthraquinone was added,
Others were processed in the same manner to prepare the light control device of the present invention. When a light resistance test was conducted in the same manner as in Example 1, ΔE was 3.0 and the light resistance was good. The parallel light transmittance of this element is 8.0% when no voltage is applied, and 75.7% when 100 V AC (60 Hz, sine wave) is applied.
Which was the same before and after the light resistance test.

Comparative Example 2 In Example 2, SC-38 (Fuji Photo Film Co., Ltd.) was used instead of the dimmer element (a) and the ultraviolet absorption filter SC-40 which were treated in the same manner except that the ultraviolet absorption filter was not used. ), The transmittance of 380 nm light is 42%, 4
A light control element (b) having a 40 nm light transmittance of 93% attached was prepared, and the same light resistance test as in Example 1 was conducted.
In the light control elements (a) and (b), ΔE is 3 each
The values were 9.0 and 15.8, which were significantly inferior to those of Example 2.

Example 3 Instead of the black dichroic dye mixture of Example 1, 0.1 g of 4-butylcyclohexyl 5-amino-6- (4-butylphenoxy) -8-hydroxy-2-anthraquinonecarboxylate is added. The others were processed in the same manner to prepare the light control device of the present invention. When a light resistance test was conducted in the same manner as in Example 1, ΔE was 2.4 and the light resistance was good. still,
This device has a parallel light transmittance of 6 when no voltage is applied.
3%, and 69.7% when an alternating current of 100 V (60 Hz, sine wave) was applied, which was unchanged before and after the light resistance test.

Comparative Example 3 In Example 3, instead of using the ultraviolet absorbing filter, the dimmer element (a) and the ultraviolet absorbing filter SC-40 treated in the same manner were replaced by SC-38 (Fuji Photo Film Co., Ltd.). ), The transmittance of 380 nm light is 42%, 4
A light control element (b) having a 40 nm light transmittance of 93% attached was prepared, and the same light resistance test as in Example 1 was conducted.
In the light control elements (a) and (b), ΔE is 3 each
The values were 2.7 and 15.7, which were inferior to those in Example 3.

Example 4 4-Butylcyclohexyl 1-amino-4- (4-butylanilino) was used in place of the black dichroic dye mixture of Example 1.
0.1 g of 2-anthraquinone carboxylate was added, and the other treatments were performed in the same manner to prepare the light control device of the present invention.
When a light resistance test was conducted in the same manner as in Example 1, ΔE was 2.1.
The light resistance was good. In this device, the parallel light transmittance was 6.7% when no voltage was applied.
When an alternating current of V (60 Hz, sine wave) is applied, 70.
It was 0% and did not change before and after the light resistance test.

Comparative Example 4 In Example 4, instead of using the ultraviolet absorbing filter, the dimmer element (a) and the ultraviolet absorbing filter SC-40 treated in the same manner were replaced by SC-38 (Fuji Photo Film Co., Ltd. ), The transmittance of 380 nm light is 42%, 4
A light control element (b) having a 40 nm light transmittance of 93% attached was prepared, and the same light resistance test as in Example 1 was conducted.
In the light control elements (a) and (b), ΔE is 4
They were 9.2 and 13.2, which were far worse than those of Example 4.

[0047]

EFFECTS OF THE INVENTION The light control material of the present invention has good film uniformity, and the light control element using the light control material has good light resistance. It is also useful as an outdoor light control device such as a light control window.
Since the light control element of the present invention has improved light resistance, it can be naturally used for a long period of time and is extremely useful industrially.

Claims (2)

[Claims] 1. A light control element having a light control material composed of a liquid crystal that controls transmission and scattering of light depending on whether an electric field is applied or not and a polymer that holds the liquid crystal between a pair of electrode substrates having electrodes on its inner surface is 380 nm. Light transmittance of 30% or less, 4
A light control element having an ultraviolet absorbing layer having a transmittance of 40 nm light of 90% or more. 2. The light control device according to claim 1, wherein the light control material contains a dichroic dye.