JP2001354952A - Production method for thermochromic material, and dimmer using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for homogeneously dispersing or dissolving a dye or a pigment in a thermochromic material, which is a highly viscous liquid or sol; and a dimmer filled with a thermochromic material obtained by the above method. SOLUTION: A colored thermochromic material is obtained by adding a solution or dispersion prepared by dissolving or dispersing a dye, an inorganic pigment and/or an organic pigment in water or an organic solvent to an aqueous solution of a polymer (e.g. hydroxypropylcellulose) or to a hydrogel and concentrating the resultant product.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a thermochromic material which changes its state at a predetermined temperature and changes its light transmittance and / or color tone. Further, the present invention relates to a colored thermochromic dimmer which can be used for an interior / exterior window material for a building, a transparent substrate for a show window, a window material for a vehicle, and the like using the method for producing a thermochromic material of the present invention.

[0002]

2. Description of the Related Art Conventionally, various dimming methods, for example, a liquid crystal dimming method, an electrochromic dimming method, a photochromic dimming method, and a thermochromic dimming method are known.

[0003] The liquid crystal light control method is based on a difference in molecular orientation depending on whether or not a voltage is applied to a liquid crystal.
Alternatively, it is a dimming method for reversibly changing to a cloudy state.

[0004] The electrochromic light control method is a light control method in which an electrochemical reaction is used to change reversibly to a transparent state or a colored state.

[0005] The photochromic dimming method is a dimming method that reversibly changes to a transparent state or a colored state with or without light irradiation.

The thermochromic dimming method is an isotropic aqueous solution of a nonionic surfactant or a nonionic water-soluble polymer which exhibits a cloud point phenomenon due to aggregation or dispersion, and is a liquid or wet gel. This is a light control method using a chromic material. The thermochromic material is a light control material that reversibly changes to a transparent state or an opaque state (opaque state) due to a phase transition or the like due to a temperature change.

In general, a thermochromic dimmer using a thermochromic material is produced by sandwiching a thermochromic material in a gap between a pair of glass substrates facing each other and sealing the periphery.

[0008]

In order to obtain a colored thermochromic light modulator, a colored transparent substrate may be used. However, assuming that a glass substrate is used as the transparent substrate, the color tone of commercially available colored transparent glass has only blue, brown, gray, and green types.
There are no bright colors such as pink and yellow. A colored transparent glass other than blue, brown, gray, and green must be separately prepared by, for example, uniformly applying a coating liquid for forming a colored film on the surface of a plate glass to form a colored film.

Coloring the thermochromic material itself with a dye or pigment gives a wider choice of color tones, and a thermochromic dimmer can be obtained at lower cost than producing and using colored transparent glass. Even if the dye or pigment is directly mixed with the thermochromic material, the dye or pigment is not easily mixed with the thermochromic material and does not disperse, because the thermochromic material is a high-viscosity aqueous polymer solution or hydrosol. Also,
Even if a water-soluble pigment is used, it hardly dissolves and does not diffuse.

[0010]

Means for Solving the Problems In order to solve the problems involved, the present inventors have used a hydroxypropylcellulose aqueous solution as a thermochromic material to uniformly disperse or dissolve a dye or pigment in a hydroxypropylcellulose aqueous solution. As a result of diligent study of the method to perform, without directly adding the dye or pigment to the high-viscosity hydroxypropylcellulose aqueous solution adjusted to a concentration suitable as a thermochromic material, the dye or pigment is dispersed or dissolved in water in advance. After stirring to make it uniform in water, it is added to the aqueous solution of hydroxypropylcellulose, and concentrated by a rotary evaporator while heating to adjust the concentration to be suitable for the thermochromic material, so that the pigment is uniformly dispersed or dissolved in the thermochromic material. Was obtained.

The thermochromic material using the obtained thermochromic material was satisfactory in both appearance and color tone change and excellent in durability.

The present invention relates to a method for producing a thermochromic material comprising a polymer aqueous solution and / or a hydrogel aqueous solution, wherein a dye, an inorganic pigment and / or an organic pigment is added to water or an organic solvent. And adding a dissolved or dispersed solution or dispersion to the mixture, and then concentrating the mixture.

Further, the present invention is the above-mentioned method for producing a thermochromic material, wherein the aqueous polymer solution is an aqueous hydroxypropylcellulose solution.

Further, the present invention provides a method for producing a liquid crystal display device, comprising:
The method for producing a thermochromic material as described above, wherein an aqueous solution of hydroxypropylcellulose filtered with a filter having a size of not more than μm is used.

Further, according to the present invention, the periphery of a pair of opposed transparent substrates separated from each other is sealed with a sealing material, and the gap is filled with a thermochromic material composed of a polymer aqueous solution and / or a hydrogel aqueous solution. A thermochromic light modulator obtained by filling a colored thermochromic material produced by the method for producing a thermochromic material described above.

As the thermochromic material used in the present invention, for example, a polysaccharide derivative having a hydroxypropyl group such as hydroxypropylcellulose or methylcellulose can be used. Since the water-soluble polymer having a hydroxypropyl group has a high degree of aggregation at high temperatures, it has excellent light-shielding properties at the time of cloudiness, and also has weather resistance. It is preferable to use a conductive polymer in the present invention.

In the present invention, the aqueous hydroxypropylcellulose solution used as the thermochromic material is obtained by dissolving a commercially available hydroxypropylcellulose powder in water. However, commercially available hydroxypropylcellulose synthesized by the polymerization reaction is a water-insoluble solid which is considered to be a highly polymerized product consisting of a three-dimensional crosslinked product of water-insoluble hydroxypropylcellulose having a diameter of 10 μm or more and 100 μm or less. Preferably, the aqueous solution of hydroxypropylcellulose dissolved in water at a concentration of 5 wt% or more and 15 wt% or less and filtered through a filter having a pore size of 0.5 μm or more and 5 μm or less is used in the present invention. It is preferable to use the method for producing a thermochromic material.

If the concentration of the aqueous solution of hydroxypropylcellulose is less than 5% by weight, it takes time and effort to concentrate the solution using a concentration means such as an evaporator. Hydroxypropylcellulose aqueous solution concentration is 15wt%
If it is larger, the viscosity of the aqueous solution of hydroxypropylcellulose becomes too high, and the filtration time becomes too long. The lower the concentration, the lower the viscosity of the aqueous solution of hydroxypropylcellulose. Therefore, even if the amount of the aqueous solution of hydroxypropylcellulose to be filtered increases, the filtration time is shortened and the filtration can be performed efficiently.

If the pore size of the filter is smaller than 0.5 μm, the filtration time is too long even if the concentration of the aqueous solution of hydroxypropylcellulose is small. If the pore size of the filter is larger than 5 μm, even if the hydroxypropylcellulose aqueous solution is filtered, fine solids remain in the hydroxypropylcellulose aqueous solution, and when the thermochromic dimmer is used, solids are visually observed by light reflection. And the appearance is poor.

By filtering under the above filtration conditions,
An aqueous solution of hydroxypropylcellulose free of solids is obtained. By using the aqueous solution of hydroxypropylcellulose in the present invention, a thermochromic light modulator having a good appearance can be obtained.

In the method for producing a thermochromic material of the present invention, the concentration of an aqueous solution of hydroxypropylcellulose is adjusted to 5 wt% or more and 15 wt% or less, and after filtration, a solution or dispersion of a dye and / or a pigment is added. It may be concentrated under reduced pressure using a rotary evaporator or the like so that the concentration becomes suitable as a thermochromic material.

In producing the thermochromic light modulator used in the present invention, the peripheral portions of a pair of opposed transparent substrates separated from each other are sealed with a sealing material, and the gap between the thermochromic material of the present invention and the gap therebetween is filled. The colored thermochromic material produced by the production method is filled. Specifically, before filling the thermochromic material between the opposing transparent substrates, it is necessary to seal the periphery of the transparent substrate. As the sealing material, it is necessary to select a material that suppresses evaporation or volatilization of the solvent of the filled thermochromic material, has good adhesiveness to the substrate, and satisfies these conditions for a long period of time under actual use conditions. For example, as an inner seal material, a band-shaped butyl tape (TB-
240), thiocol or the like can be used as the outer seal material.

According to the present invention, a thermochromic material, which is a high-viscosity aqueous solution of a polymer or an aqueous hydrogel, has a high viscosity, so that a colored thermochromic material is obtained without dissolving or dispersing even when dyes and pigments are directly added. Because there is no, devising a manufacturing method to obtain a colored thermochromic material, a solution or dispersion in which a dye or pigment is dissolved or dispersed in water or an organic solvent in advance in an aqueous polymer solution or aqueous hydrogel solution Are mixed and concentrated to obtain a colored thermochromic material.

The transparent substrate constituting the thermochromic light modulating body using the colored thermochromic light modulating material of the present invention may be a transparent substrate coated with a colored film by various coating methods, or the transparent substrate itself. Can be used, but in the present invention, since the thermochromic light modulator is colored by a thermochromic material, the substrate constituting the thermochromic light modulator is preferably colorless and transparent.

Note that the transparent substrate is not limited to a glass plate, and a transparent plastic plate can be used.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic cross-sectional view showing an example of a thermochromic dimmer 1 produced by the method for producing a thermochromic dimmer of the present invention.

The thermochromic dimmer 1 has a structure in which a colored thermochromic material 2 is sealed by an inner seal material 4 and an outer seal material 5 in a gap between a pair of separated transparent substrates.

As the thermochromic material 2, for example,
Hydroxypropylcellulose aqueous solution is mentioned, and coloring source includes various dyes and pigments.

Specific examples of the dyes and pigments confirmed to be usable in the present invention are listed below. Examples of the dye include alcohol-soluble metal complex dyes (trade name, Aizenspirone, type RED) manufactured by Hodogaya Chemical Industry Co., Ltd. GEH,
RED C-BH, BlueGNH, Blue CR
H, VIOLET RH, BROWN RH)
Examples of the pigment include Glass staineder (trade name, manufactured by Dainichi Seika Co., Ltd.), which is a water-soluble resin coating obtained by combining an organic pigment and a solvent that dissolves a water-soluble resin, and includes, for example, CS PINK NG5- 1,
CS BLUENG2-1, CS YELLOW E1
2-1 and quinacudrine = pigment violet 19 and the like. When a thermochromic dimmer 1 composed of an aqueous solution of hydroxypropylcellulose colored using a dye or a pigment was prepared, the thermochromic dimmer 1 was dissolved or dissolved in an aqueous solution of hydroxypropylcellulose as a thermochromic material 2 sandwiched between a pair of substrates. The dispersed dyes and pigments were in a high-viscosity aqueous solution of hydroxypropylcellulose and maintained a good colored state without reaggregation.

After the above dye or pigment is dispersed or dissolved in water, it is mixed with an aqueous solution of hydroxypropylcellulose, which is a thermochromic material 2, to obtain a colored thermochromic material 2.
Was satisfactory in both appearance, color change and durability, but if a colored thermochromic light control body 1 with satisfactory appearance, color change and durability could be obtained, the dye or pigment was replaced with water instead of water. It may be dissolved or dispersed in an organic solvent.

In the method for producing the thermochromic material 2 of the present invention, if the aqueous polymer solution as the thermochromic material 2 can be colored, it is possible to use dyes and pigments other than the dyes and pigments described above. By mixing various dyes or pigments, it is possible to produce thermochromic light modulators 1 of various colors.

Hereinafter, the present invention will be described with reference to Examples.
The present invention is not limited by the following examples.

[0033]

EXAMPLE A powder of hydroxypropylcellulose (trade name: HPC-L) manufactured by Nippon Soda Co., Ltd. was added to ion-exchanged water so as to have a concentration of 10 wt%, and prepared in a beaker. It was placed in a container with an ultrasonic oscillator filled with water, and ultrasonic waves were emitted to dissolve it. To remove undissolved material,
The prepared solution of 10% by weight of hydroxypropylcellulose was filtered by suction with a filter made of cellulose acetate having a pore size of 0.8 μm, which is a hydrophilic filter.

Next, a metal complex salt dye (trade name, Aizenspirone dye) manufactured by Hodogaya Chemical Industry Co., Ltd., which is soluble in alcohol but not in water, having a concentration of 1% by weight.
Then, the mixture was added to ion-exchanged water, sealed in a container together with zirconia balls having a diameter of 1.2 mm, and the dye was pulverized for 2 hours and dispersed in water by rotating a ball mill at 200 revolutions per minute. Eizenspirone dyes include red dye RED GEH and red dye RED
C-BH, Blue GNH which is a blue dye, Blue C-RH which is also a blue dye, V which is a violet dye
There are types such as IOLET RH and BROWN RH which is a brown dye.

A dye dispersion adjusted to a concentration of 1 wt% was added to an aqueous solution of hydroxypropyl cellulose adjusted to a concentration of 10 wt% in a weight percentage to give a hydroxypropyl cellulose 1 solution.
0 wt% aqueous solution: 1 wt% dye dispersion liquid was added so as to be 95: 5. Then, while sucking with a rotary evaporator, water as a solvent was evaporated and concentrated twice to obtain a colored hydroxypropyl alcohol aqueous solution. That is, a colored thermochromic material 2 was obtained.

The production of the thermochromic light modulator 1 was performed as follows. The prepared colored thermochromic material 1 was placed on the center of a 10 cm square glass substrate 3 by 2.
After weighing g, a butyl tape was placed on the outer periphery of the glass substrate as the inner seal material 4, and thiochol was placed as an outer seal material 5 on the outside thereof.

Further, after the injection needle was arranged in a square, the glass substrate 3 'was placed above the injection needle, and only the glass portion was pressed to press the glass substrate 3 and the glass substrate 3'. Thereafter, a silicone hose was connected to the four injection needles arranged at the four corners of the glass substrates 3 and 3 ', and the air in the cell was exhausted by a vacuum pump. When the thermochromic material 2 is completely spread by evacuating, the vacuum pump is stopped, and the four holes are sealed with an epoxy sealant.
The sealing material was reacted and cured by ultraviolet light by irradiating ultraviolet light.

[0038] RED GE
H, RED C-BH, Blue GNH, Blue
Thermochromic dimmers were prepared in accordance with the above procedure using a total of six types of C-RH, VIOLET RH, and BROWN RH. The thermochromic light controller 1 was solid and the like, was not visually observed, had a good appearance, became cloudy quickly at 70 ° C., and was satisfactory as the thermochromic light controller 1. Comparative Example In the preparation of a thermochromic material, powder of hydroxypropylcellulose (trade name: HPC-L) manufactured by Nippon Soda Co., Ltd. was dissolved in ion-exchanged water while applying vibration by ultrasonic waves, as in Example 1, and 10 wt. %, And then suction-filtered with a filter made of cellulose acetate having a pore size of 0.8 μm. Thereafter, the mixture was concentrated under reduced pressure with a rotary evaporator to a concentration of 20 wt%.

An attempt was made to directly add and dissolve various Aizen spiron dyes to a 20 wt% aqueous solution of hydroxypropylcellulose, which is a thermochromic material 2, but they did not dissolve at all, but precipitated as a lump.

[0040]

According to the present invention, there is provided a colored thermochromic dimmer according to the present invention in which a solution or dispersion obtained by previously dissolving or dispersing a dye or pigment in water or an organic solvent is mixed with an aqueous polymer solution or aqueous hydrogel solution. In the production method, the aqueous polymer solution and the aqueous hydrogel solution that are thermochromic materials have high viscosity, and even if dyes and pigments are directly added, a colored thermochromic material without dissolving or dispersing cannot be obtained. Will be resolved.

By using various dyes or pigments or by mixing them, it is possible to produce thermochromic dimmers of various colors.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view of an example of a dimmer using a colored thermochromic material manufactured by a method for manufacturing a thermochromic material of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Dimmer 2 Thermochromic material 3.3 'Glass substrate 4 Inner seal material 5 Outer seal material

Claims (4)

[Claims] 1. A method for producing a thermochromic material comprising an aqueous polymer solution and / or an aqueous hydrogel solution, wherein a dye, an inorganic pigment and / or an organic pigment is dissolved in water or an organic solvent in the aqueous polymer solution or the hydrogel. Alternatively, a method for producing a thermochromic material, comprising adding a dispersed solution or dispersion and then concentrating the solution. 2. The method for producing a thermochromic material according to claim 1, wherein the aqueous polymer solution is an aqueous hydroxypropylcellulose solution. 3. The method for producing a thermochromic material according to claim 2, wherein an aqueous solution of hydroxypropylcellulose filtered with a filter having a pore size of 0.5 μm or more and 5 μm or less is used. 4. A thermoplast comprising a pair of opposing transparent substrates which are separated from each other, sealed with a sealing material, and filled with a thermochromic material comprising a polymer aqueous solution and / or a hydrogel aqueous solution. A thermochromic light modulating body, which is filled with a colored thermochromic material produced by the method for producing a thermochromic material according to claim 1.