JP2002214653A - Light controllable material, light controllable film and method of manufacturing light controllable film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light controllable film which is changed in light transmittability by the presence or absence of an electric field, is controllable in the entire incident light quantity, does not flocculate and settle light polarization particles, can exhibit a stable light controllable function and can facilitate manipulation for spacing maintenance, etc., of a substrate in manufacturing and a method of manufacturing the same. SOLUTION: This light controllable material contains a high-molecular medium which consists of a silicone resin having a substituent possessing an ethylenically unsaturated bond and a photopolymerization initiator and is cured by irradiation with UV rays and a light polarization suspension which is dispersed with particles having an aspect ratio of 1.1 to 4.0 in a dispersion medium in a flowable state. The dispersion medium in the light polarization suspension can be separated in phases from the high-polymer medium and the cured matter thereof.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dimming material suitably used for window glass, various flat display devices, substitutes for various liquid crystal display devices, optical shutters, advertisement and information display panels, glasses, sunglasses, and the like. The present invention relates to a light control film using the same and a method for producing the same.

[0002]

BACKGROUND OF THE INVENTION Dimmable glass containing a light polarizing suspension is disclosed in Edwin. Land (U.S. Pat. No. 1,955,923; U.S. Pat. No. 1,961).
3,496) was first invented,
This configuration has a structure in which a light polarization suspension in a liquid state is injected between two transparent conductive substrates having a small space. According to Edwin Land's invention, a liquid light polarization suspension injected between two transparent conductive substrates is a light polarization dispersion that is dispersed in the suspension when no electric field is applied. Due to the Brownian motion of the particles, most of the incident light is reflected, scattered or absorbed by the light polarizing particles, and only a small portion is transmitted. That is, the degree of transmission, reflection, scattering, or absorption is determined by the shape, properties, concentration, and amount of irradiated light energy of the light polarizing particles dispersed in the light polarizing suspension. When an electric field is applied to the dimming window using the dimming glass having the above structure, an electric field is formed in the light polarization suspension through the transparent conductive substrate, and the particles exhibiting the light polarization function are polarized, and become parallel to the electric field. Light is transmitted through the array and between or through the particles, and eventually the dimming glass becomes transparent. However, such initial light control devices are, in practice, agglomeration of light-polarized particles in a light-polarized suspension, sedimentation by their own weight, hue change due to heat, change in optical density, deterioration due to ultraviolet irradiation, Practical use has been difficult due to difficulties in maintaining the interval and injecting the optically polarized suspension into the interval.

[0003] Robert El Sachs
t. L. Saxe) U.S. Patent No. 3,756,70
No. 0, 4,247,175, 4,273,422,
Nos. 4,407,565 and 4,422,963, or F.C. Lowell (FC Low).
ell), U.S. Pat. No. 3,912,365 to RI Thompso.
n) U.S. Pat. No. 4,078,856 describes the initial problems of dimming windows: aggregation and settling of light polarizing particles,
A light control window using a light control glass supplementing a change in optical density or the like is disclosed. In these patents, the density of the light-polarized particles and the suspending agent is reduced by a liquid-state light-polarized suspension composed of acicular light-polarized crystal particles, a suspending agent for dispersing crystal particles, a dispersion preparation, and a stabilizer. Almost in the same way, while preventing the sedimentation of the light-polarized particles, the dispersing agent is added to enhance the dispersibility of the light-polarized particles, thereby preventing aggregation of the particles and solving the problems of the earlier patent. However, these light control glass also have a structure in which a liquid light polarization suspension is sealed in the space between two transparent conductive substrates, like a conventional light control glass. In such a case, it is difficult to fill a uniform suspension into the space between the two transparent conductive substrates.
For example, changes in the spacing between the substrates due to wind pressure, resulting in a change in optical density and inhomogeneous hues, or a break in the surrounding sealant for collecting liquid between the transparent conductive substrates, There is a problem that the light polarizing material leaks.
Further, the response time becomes uneven due to deterioration due to ultraviolet rays and a voltage drop between the peripheral portion and the central portion of the transparent conductive substrate.

On the other hand, a dimming window using a dimming glass using a liquid crystal such as a nematic liquid crystal as a light polarization functional material is disclosed in J.
U.S. Patent Nos. 4,435,047, 4,579,423, 4,6 to J. Fergason.
16,903, JL West (J.
L. West) U.S. Pat. No. 4,685,771. The dimming glass according to these patents has a film in which fine liquid crystal capsules are dispersed.
It is in the form of being inserted between two transparent conductive substrates. When no electric field is applied to the dimming window using these dimming glass, the nematic liquid crystal contained in the dispersed spherical capsule is aligned along the interface of the capsule. The incident light is birefringent at the capsule interface because the refractive index of the polymer resin, which is the film matrix surrounding, does not match. The refracted light continues to be refracted and scattered in different directions from each other at the interface of the other capsule, so that the dimming window has a translucent milky white state. However, when an electric field is applied, the rod-like molecules of the nematic liquid crystal are arranged in parallel to the electric field, so that the refractive index of the liquid crystal and the refractive index of the polymer resin as the film matrix become the same, and no birefringence occurs. Light passes through. In the case of manufacturing a film used for the light control window, an appropriate amount of liquid crystal is mixed with an aqueous solution in which a water-soluble polymer substance is dissolved, and the emulsion state (polymer) is stirred by mechanical stirring or ultrasonic stirring. After the liquid is encapsulated in an aqueous solution), coated on a transparent conductive substrate to a certain thickness, and then evaporated at normal or appropriate temperature to evaporate water to form a film. There is a method of producing a film by phase separation by change.

[0005] However, since the light variable effect of the light control glass using the liquid crystal utilizes the scattering due to the sub refraction, only the transmittance of the vertically incident light (or parallel light) can be adjusted. Since the adjustment of the amount of incident light is weak, it is difficult to use it as a display element. Such a dimming glass shows a milky white translucent state when no electric field is applied, and a light scattering phenomenon occurs even when an electric field is applied, leaving a completely unclear emulsion state. Be in a transparent state. Therefore, a display function by blocking and transmitting light, which is used as an operation principle of the existing liquid crystal display element, cannot be performed. In addition, in the process of forming a liquid crystal film, a part of the liquid crystal acts as a plasticizer for the polymer resin, and in general, a composite liquid crystal is used. Since it is difficult to match the refractive index of the molecular resin, a light scattering phenomenon occurs even when an electric field is applied, resulting in a transparent state in which an emulsion state that is not completely clear remains. Further, since the liquid crystal and the polymer resin have low durability against ultraviolet rays, complicated processing such as adding an ultraviolet ray blocking film or mixing an ultraviolet ray absorbing agent is required. Further, the range of the operating temperature is limited due to the thermal characteristics of the nematic liquid crystal.

The above-mentioned Robert El Sachs (Robe)
rt. L. When a film is manufactured using the light-polarized light suspension disclosed in the patent of Saxe et al. As it is, the liquid light-polarized light suspension is mixed with a polymer resin solution, a phase separation method by polymerization, solvent volatilization is performed. When a film is manufactured using a phase separation method based on temperature or a phase separation method based on temperature, a conventional light-polarized suspension is composed of a multi-component substance such as a stabilizer, a dispersant, and an ultraviolet absorber. In the process of phase separation, the light-polarized particles contained in the liquid light-polarized suspension are not caught in the phase-separated droplets, and are cured. A problem arises in that it cannot be changed with the electric field by remaining in the space. Also, generally, in order to improve the dispersibility of the light polarizing particles in a specific suspension by forming particles of uniform size in the process of synthesizing the light polarizing particles, a polymer such as nitrocellulose is used. Although treated with a substance, nitrocellulose has an affinity for the polymer resin that is the film matrix,
Light-polarized particles treated with nitrocellulose during phase separation are not caught in the separated droplets but remain in the polymer resin, so that the variable ability by an electric field is reduced.

[0007]

SUMMARY OF THE INVENTION The present invention relates to a light control film whose light transmittance changes depending on the presence or absence of an electric field. The light control film is capable of controlling the total amount of incident light, and is free from aggregation and sedimentation of light-polarized particles. It is an object of the present invention to provide a light control film capable of exhibiting a light control function in which a light control function is performed and facilitating operations such as maintaining a distance between substrates even during production, and a method of manufacturing the same. Another object of the present invention is to provide a light control material that is suitably used for manufacturing the light control film. Further, the present invention reduces the decrease in the variable ability of the light polarizing particles due to the electric field, furthermore, has excellent durability against ultraviolet rays,
It is another object of the present invention to provide a light control film having excellent thermal stability, a method for producing the same, and a light control material used for the same.

[0008]

The present invention provides the following light control material, light control film, and method for manufacturing the light control film. (1) A polymer medium comprising a silicone resin having a substituent having an ethylenically unsaturated bond and a photopolymerization initiator, which is cured by irradiation with ultraviolet light, and has an aspect ratio of 1.0 to 4.0. A light-polarizing suspension dispersed in a dispersion medium in a state where the particles are in a flowable state, wherein the dispersion medium in the light-polarizing suspension can be phase-separated from a polymer medium and a cured product thereof. Some dimming materials. (2) The light modulating material according to (1), wherein the dispersion medium in the light polarization suspension has incompatibility or partial compatibility with the polymer medium. (3) The light modulating material according to (1) or (2), wherein the particles in the light polarization suspension are dichroic crystals. (4) The light modulating material according to any one of (1) to (3), wherein the dispersion medium in the light polarization suspension is an acrylic ester oligomer having a fluoro group and a hydroxyl group. (5) A light control film formed by using the light control material according to any one of (1) to (4), wherein a light is dispersed in the solid resin matrix and a solid resin matrix formed from a polymer medium. A light control film having a light control layer comprising a polarizing suspension. (6) The light control film according to (5), wherein the light control layer is sandwiched between two transparent conductive substrates. (7) The light modulating material according to (1) is applied on a transparent conductive substrate, and the silicone resin is cured by irradiating ultraviolet rays to form a light modulating layer, and the transparent conductive substrate is formed on the light modulating layer. A method for producing a light control film, which is characterized in that the film is brought into close contact.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The photochromic material of the present invention comprises a silicone resin having a substituent having an ethylenically unsaturated bond and a photopolymerization initiator, and is cured by irradiation with ultraviolet rays. And the aspect ratio is 1.0 to
And a light-polarizing suspension in which the particles having a particle diameter of 4.0 are dispersed in a dispersion medium in a flowable state, wherein the dispersion medium in the light-polarizing suspension is a polymer medium and a cured product thereof. It can be phase separated. Using the light modulating material of the present invention, a film light modulating layer in which a light polarization suspension is dispersed in a solid resin matrix formed of a polymer medium is sandwiched between two transparent conductive substrates or the like. Thereby, the light control film of the present invention is obtained. That is, in the light control layer of the light control film of the present invention, the liquid light polarization suspension is dispersed in the form of fine droplets in the solid polymer resin. When an electric field is applied to such a light control film, particles having an electric dipole moment suspended and dispersed in droplets of a light polarization suspension dispersed in a solid resin matrix are parallel to the electric field. The droplets are converted to a transparent state by the arrangement, and the incident light is transmitted with little scattering due to the viewing angle or little decrease in transparency. By forming the light control layer into a film as described above, the problems of the light control glass according to the conventional technology, that is, the difficulty of injecting a liquid suspension between two transparent conductive substrates, This solves the problem of expansion of the lower part due to the difference in water pressure between the upper and lower parts, local hue change due to the change of the substrate interval due to the external environment such as wind pressure, and leakage of the dimming material due to the destruction of the sealing material between the transparent conductive substrates. Further, since no liquid crystal is used, a change in color tone and a decrease in variable ability due to exposure to ultraviolet light, and a difference in response time due to a voltage drop between a peripheral portion and a central portion of a transparent conductive substrate, which is peculiar to a large product, are eliminated.

As the polymer medium and the dispersion medium (dispersion medium in the optically polarized light suspension), a polymer medium, a cured product thereof, and a dispersion medium capable of at least phase-separating from each other when formed into a film are used. . It is preferable to use a combination of a polymer medium and a dispersion medium that are incompatible or partially compatible with each other.

The polymer medium used in the present invention comprises:
It comprises (A) a silicone resin having a substituent having an ethylenically unsaturated bond and (B) a photopolymerization initiator, and is cured by irradiation with ultraviolet rays. As specific examples, for example, Japanese Patent Publication No. 53-36515,
The compositions described in JP-A-7-52371, JP-B-58-53656, JP-B-61-17863 and the like can be mentioned.

These silicone resins include, for example, silanol polydimethylsiloxanes at both ends, silanol polydiphenylsiloxane-dimethylsiloxane copolymers at both ends, silanolsiloxane polymers at both ends such as silanol polydimethyldiphenylsiloxane at both ends, and trisilanes such as trimethylethoxysilane. A dehydrocondensation reaction and a dealcoholation of an ethylenically unsaturated bond-containing silane compound such as alkylalkoxysilane and (3-acryloxypropyl) methyldimethoxysilane in the presence of an organic tin catalyst, 2-ethylhexanetin. It is synthesized by reacting. As a form of the silicone resin, a solventless type is preferably used. That is, when a solvent is used for the synthesis of the silicone resin, it is preferable to remove the solvent after the synthesis reaction. The weight average molecular weight of these silicone resins in terms of polystyrene obtained by gel permeation chromatography is from 20,000 to 100,000.
0, preferably 30,000-80,000
Is more preferable. The amount of the ethylenically unsaturated bond-containing silane compound such as (3-acryloxypropyl) methoxysilane is preferably 2 to 30% by weight of the total amount of the raw material siloxane and the silane compound, and is preferably 5 to 18%.
It is more preferable to set the weight%.

Photopolymerization initiators that activate radical polymerization upon exposure to ultraviolet light are described in J. Am. Photochem.
Sci. Technol. , 2, 283 (19
77), specifically 2,2-dimethoxy-1,2-diphenylethan-1-one, 1- (4
-(2-hydroxyethoxy) phenyl) -2-hydroxy-2-methyl-1-propan-1-one, bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide, 2-hydroxy-2-methyl- 1-
Phenylpropan-1-one, (1-hydroxycyclohexyl) phenyl ketone and the like can be used.

The amount of the photopolymerization initiator to be used is preferably 0.05 to 20 parts by weight, more preferably 0.1 to 5 parts by weight, based on 100 parts by weight of the above silicone resin.

In addition to the above-mentioned ultraviolet-curable silicone resin, an organic solvent-soluble resin or a thermoplastic resin, for example, having a weight-average molecular weight in terms of polystyrene of 1,000 as measured by gel permeation chromatography.
-100,000 polyacrylic acid, polymethacrylic acid, etc. can also be used in combination.

Further, additives such as a coloring inhibitor such as dibutyltin dilaurate may be added to the polymer medium as required.

The dispersion medium in the light-polarized suspension used in the above combination serves as a dispersion medium in the light-polarized suspension, and is selectively adhered and coated on particles to form a polymer medium. During the phase separation, the particles act to move to the phase-separated droplet phase, have no electrical conductivity, have no affinity with the polymer medium, and have a It is preferable to use a liquid copolymer having a refractive index similar to that of the solid resin matrix to be formed. For example, a (meth) acrylate oligomer having a fluoro group and / or a hydroxyl group is preferable, and a (meth) acrylate oligomer having a fluoro group and a hydroxyl group is more preferable. When such a copolymer is used, one monomer unit of either a fluoro group or a hydroxyl group is directed to the light polarizing particles, and the remaining monomer units are stably maintained as droplets of the light polarizing suspension in the polymer medium. The light-polarizing particles are dispersed very homogeneously in the light-polarizing suspension, and during the phase separation, the light-polarizing particles are guided into the droplets that are phase-separated. Examples of the acrylate oligomer having a fluoro group and / or a hydroxyl group include 2,2,2-trifluoroethyl methacrylate / butyl acrylate /
2-hydroxyethyl acrylate copolymer, 3,5,5-trimethylhexyl acrylate / 2-hydroxypropyl acrylate / fumaric acid copolymer, butyl acrylate / 2-hydroxyethyl acrylate copolymer, acrylic acid 2,2,3,3-tetrafluoropropyl / butyl acrylate / 2-hydroxyethyl acrylate copolymer, 1H, 1H, 5H-octafluoropentyl acrylate / butyl acrylate / 2-hydroxyethyl acrylate copolymer 1H, 1H, 2H, 2H-heptadecafluorodecyl acrylate / butyl acrylate / 2-hydroxyethyl acrylate copolymer, methacrylic acid 2,
2,2-trifluoroethyl / butyl acrylate / 2-hydroxyethyl acrylate copolymer, 2,2,3,3-tetrafluoropropyl methacrylate / butyl acrylate / 2-hydroxyethyl acrylate copolymer, 1H, 1H, 5H-octafluoropentyl methacrylate / butyl acrylate / 2-hydroxyethyl acrylate copolymer, 1H, 1H, 2H, 2H-heptadecafluorodecyl methacrylate / butyl acrylate / 2-hydroxy acrylate Ethyl copolymer and the like can be mentioned. More preferably, it has both a fluoro group and a hydroxyl group. These acrylate oligomers preferably have a weight average molecular weight in terms of standard polystyrene measured by gel permeation chromatography of 1,000 to 20,000, more preferably 2,000 to 10,000. . The amount of the fluoro group-containing monomer used as a raw material of these acrylic acid ester oligomers is preferably 6 to 12 mol%, more preferably 7 to 8 mol%, of the total amount of the raw material monomers. If the amount of the fluoro group-containing monomer exceeds 12 mol%, the refractive index tends to increase, and the light transmittance tends to decrease. The amount of the hydroxyl group-containing monomer used as a raw material of these acrylic acid ester oligomers is 0.5 to
The content is preferably 22.0 mol%, more preferably 1 to 8 mol%. The amount of the hydroxyl-containing monomer used is 2
When it exceeds 2.0 mol%, the refractive index becomes large,
Light transmittance tends to decrease.

The light-polarizing suspension used in the present invention is a dispersion in which particles having an aspect ratio of 1.0 to 4.0 are dispersed in a dispersion medium in a flowable manner. The particles, for example, have no affinity for the polymer medium, or the resin component in the polymer medium, that is, the silicone resin having a substituent having an ethylenically unsaturated bond, and can enhance the dispersibility of the particles. In the presence of a polymer dispersing agent, pyrazine-2,3-dicarboxylic acid dihydrate, pyrazine-2,5-dicarboxylic acid dihydrate, pyridine- Needle-like small crystals of polyperiodide produced by reacting one substance selected from the group consisting of 2,5-dicarboxylic acid monohydrate with iodine and iodide are preferably used. Examples of the polymer dispersant that can be used include nitrocellulose. Examples of the iodide include calcium iodide. Examples of the polyperiodide thus obtained include those represented by the following general formula: CaI ₂ (C ₆ H ₄ N ₂ O ₄ ) .XH ₂ O (X: 1 to 2).

Further, US Pat. No. 2,041,138 (E.I.
H. Land), U.S. Pat. No. 2,306,108 (Land et al.), U.S. Pat. No. 2,375,963.
Specification (Thomas), US Patent No. 4,270,8.
The particles disclosed in RL Saxe 41 and GB 433,455 can also be used. Crystals of polyiodide known by these patents are prepared by selecting one of pyrazine carboxylic acid and pyridine carboxylic acid and reacting with iodine to obtain polyiodide, polychloride or polybromide. Of polyhalide. These polyhalides are complex compounds in which a halogen atom has reacted with an inorganic or organic substance.
For example, it is disclosed in Sax US Pat. No. 4,422,963.

As disclosed by Sax, in the process of synthesizing light-polarized crystal particles, to form particles of uniform size and to improve the dispersibility of the particles in a particular suspension medium. For this reason, it is preferable to use a polymer substance such as nitrocellulose. When using a crystal coated with a polymer substance such as nitrocellulose thus obtained as particles, the curable polymer that has been used as a conventional polymer medium has an affinity for nitrocellulose, Particles treated with nitrocellulose do not float in droplets separated during phase separation, but remain in the solid resin matrix and may lose their variable ability. In the present invention, by using a silicone resin having a substituent having an ethylenically unsaturated bond as a curable polymer medium, particles can be easily formed into fine droplets formed by phase separation during film production. Dispersion and floating can result in excellent variable ability.

In addition to the above particles, for example, phthalocyanine compounds represented by the following general formula, such as inorganic fibers such as carbon fibers, τ-type metal-free phthalocyanine and metal phthalocyanine, can also be used. In the phthalocyanine compound represented by the following general formula, the central metal M is copper,
Examples include nickel, iron, cobalt, chromium, titanium, beryllium, molybdenum, tungsten, aluminum, chromium, and the like.

[0022]

Embedded image (Wherein, M represents. A central metal or H ₂₎ in the present invention, the aspect ratio measurement of scanning electron microscope of particles, randomly selected the 50 particles major and minor axis ratio of It can be obtained as an average value. The aspect ratio of the particles in the present invention is from 1.1 to 4.0, and preferably from 1.1 to 3.0. When the aspect ratio is less than 1.1 or more than 4.0, the orientation motion in the light polarization suspension is reduced when an electric field is applied. Further, it is preferable that the aspect ratios of all 50 particles fall within this range. In the present invention, the size of the particles is preferably 1 μm or less in a major axis, and 0.1 to
1 μm, more preferably 0.2 to 0.6
μm is preferred. When the size of the particles exceeds 1 μm, problems such as light scattering occur and a decrease in transparency such as a decrease in alignment motion in a light polarization suspension when an electric field is applied occur. There is.

The light polarization suspension used in the present invention preferably comprises 1 to 70% by weight of particles and 30 to 99% by weight of a dispersion medium, and 4 to 50% by weight of particles and 50 to 9% of a dispersion medium.
More preferably, it comprises 6% by weight.

The light modulating material of the present invention comprises a light polarizing suspension in an amount of usually 1 to 100 parts by weight per 100 parts by weight of a polymer medium.
Preferably, it is contained in an amount of 6 to 70 parts by weight, more preferably 6 to 60 parts by weight.

The light control film of the present invention is a light control film formed using the light control material of the present invention, and comprises a solid resin matrix formed from a polymer medium and a light dispersed in the solid resin matrix. It has a light control layer composed of a polarizing suspension. The light control layer is usually sandwiched between two transparent conductive substrates.

The light control film of the present invention is prepared by, for example, mixing the light control material of the present invention and subjecting the mixture to known coating means such as a bar coater, an applicator, a doctor blade, a roll coater, a die coater, and a comma coater. It is applied to a substrate such as a transparent conductive substrate. When applying, it may be diluted with an appropriate solvent, if necessary. When a solvent is used, drying is required after coating on a substrate. As the solvent, tetrahydrofuran, toluene, heptane, cyclohexane, ethyl acetate, ethanol, methanol, isoamyl acetate, hexyl acetate and the like can be used. In order to form a film in which a liquid light polarization suspension is dispersed in the form of fine droplets in a solid polymer matrix, the light modulating material of the present invention is mixed with a homogenizer, an ultrasonic homogenizer, or the like. Utilizing a method of finely dispersing an optically polarized light suspension in a polymer medium, a phase separation method by polymerization of a silicone resin component in a polymer medium, a phase separation method by volatilization of a solvent, or a phase separation method by temperature. Can be.

When a water-based emulsion method is used in the production of a light control film using a liquid crystal, which is a conventional technique, the liquid crystal often loses the light polarization characteristics due to the reaction with moisture, and a film having the same characteristics is often used. There is a problem that it is difficult to manufacture. In the present invention, since a liquid light polarization suspension in which particles are dispersed in a light polarization suspension is used instead of a liquid crystal, an electric field is different from a film-type light control glass using a liquid crystal. Even when no voltage is applied, light is not scattered, and the coloring state is excellent and the viewing angle is not limited. The light variability can be arbitrarily adjusted by adjusting the content of the light-polarizing particles, the shape and thickness of the droplets, or adjusting the electric field intensity.

For example, a light control material is mixed to form a liquid dispersion in which an optically polarized light suspension containing particles is dispersed in a silicone resin or a solution thereof in the form of droplets, and this mixed liquid is placed on a transparent conductive substrate. The light modulating film can be suitably manufactured by forming a light modulating layer by applying the ultraviolet light to the silicone resin and curing the silicone resin by irradiating ultraviolet rays thereto, and bringing the transparent conductive substrate into close contact with the light modulating layer. The amount of the light polarization suspension in the light control material of the present invention was 1 to 100 parts by weight of the silicone resin.
The amount is preferably from 100 to 100 parts by weight, more preferably from 4 to 70 parts by weight, even more preferably from 8 to 60 parts by weight, even more preferably from 8 to 50 parts by weight. In addition, the amount of the photopolymerization initiator is the same as that of the silicone resin 10.
The amount is preferably 0.1 to 20 parts by weight, more preferably 1 to 10 parts by weight, based on 0 parts by weight. First, a liquid polarization suspension is homogeneously mixed with a silicone resin having a substituent having an ethylenically unsaturated bond (or a solution thereof) and a polymer medium containing a photopolymerization initiator. The suspension is a liquid mixture in which the suspension is dispersed in the form of droplets in a silicone resin or a solution thereof. This mixed solution is applied on a transparent conductive substrate in a constant thickness, and after drying and removing the solvent as necessary, the silicone resin is cured by irradiating ultraviolet rays using a high-pressure mercury lamp or the like. As a result, a film is formed in which the liquid light polarization suspension is dispersed in the form of droplets in the solid resin matrix made of the cured silicone resin. By varying the mixing ratio between the polymer medium and the liquid light polarization suspension, the light transmittance of the film can be adjusted. A light control film is obtained by bringing another transparent conductive substrate into close contact with the film-like light control layer formed in this manner. A light control layer may be formed on both of the two transparent conductive substrates, and the light control layers may be laminated so that the light control layers are in close contact with each other. The thickness of the light control layer is 5 to 1,000.
0 μm is preferable, and 20 to 100 μm is more preferable.

The size of the droplet of the light-polarized suspension dispersed in the solid resin matrix (the diameter of the droplet as measured by an optical microscope) is preferably 0.5 to 100 μm, and 1 to 5 μm.
μm is more preferred. The size of the droplet depends on the concentration of each component constituting the light-polarized suspension, the viscosity of the light-polarized suspension and the polymer medium, and the compatibility of the dispersion medium in the light-polarized suspension with the polymer medium. Etc.

According to the above method, a light control film whose light transmittance can be arbitrarily adjusted by forming an electric field is provided.
The light control film maintains a sharply colored state without light scattering even when an electric field is not formed, and is converted to a transparent state when an electric field is formed. This ability is 20
Shows reversible repetition properties of more than 10,000 times. The transmittance enhancement in the transparent state and the sharpness enhancement in the colored state are caused by the refractive index of the liquid light polarization suspension and the refractive index of the silicone resin having a substituent having an ethylenically unsaturated bond. Fulfill by matching. The power supply used is AC,
It can operate at 100 volts (effective value) and a frequency range of 30 Hz to 500 kHz. The response time to an electric field is within 1 to 50 seconds when decoloring, and within 1 to 100 seconds when coloring. UV durability shows stable variable characteristics even after 250 hours as a result of an ultraviolet irradiation test using 750 W ultraviolet light, etc., and the initial variable characteristics even when left at −50 ° C. to 90 ° C. for a long time. Was found to be maintained.

The transparent conductive substrate used for producing a light control film using the light control material according to the present invention is generally a transparent conductive film (IT) having a transmittance of 80% or more.
A transparent substrate coated with a film of O, SnO ₂ , In ₂ O ₃ or the like and having a surface resistance of 3 to 600Ω (for example, a polymer film such as glass or polyethylene terephthalate) can be used. Has a thickness of 10
The thickness is preferably 5,000 nm, and the thickness of the transparent substrate is not particularly limited. For example, in the case of glass, 1 to 15
mm, preferably 10 to 20 in the case of a polymer film.
0 μm is preferred. Uses a substrate with a transparent insulating layer with a thickness of about 200 to 1,000 angstroms formed on a transparent conductive layer in order to prevent short-circuiting phenomena caused by mixing of foreign substances, etc. May be.
In the case of a reflective dimming window (for example, a rear view mirror for an automobile), a thin film of a conductive metal such as aluminum, gold, or silver, which is a reflector, may be directly used as an electrode.

When no electric field is applied to the light control film according to the present invention, the particles exhibit a sharp coloration due to the light absorption and dichroism effect of the particles due to Brownian motion of the particles in the light polarization suspension. However, when an electric field is applied, the light polarizing particles in the droplet or droplet concatenation are arranged parallel to the electric field,
When a dispersion medium having a refractive index difference of 0.005 or less from the solid resin matrix is used, the state changes to a transparent state, and there is no scattering due to a viewing angle and a decrease in transparency. In addition, since it is in the form of a film, there is a problem with the conventional dimming glass that uses the liquid light polarization suspension as it is, that is, injection of the liquid suspension between two transparent conductive substrates. Difficulties, expansion of the lower part due to the water pressure difference between the upper and lower parts of the product, local hue change due to changes in the sense of the substrate due to the external environment such as wind pressure, and dimming The leak is resolved. In addition, a change in color tone and a decrease in variable capability due to exposure to ultraviolet light, and a difference in response time due to a voltage drop between the peripheral portion and the central portion of the transparent conductive substrate, which is peculiar to large products, are eliminated. Further, in the case of a dimming window using a liquid crystal according to the related art, the liquid crystal is easily deteriorated by ultraviolet rays, and the operating temperature range is narrow due to the thermal characteristics of the nematic liquid crystal. Furthermore, also on the optical characteristic surface, when an electric field is not applied, it shows a milky white translucent state due to light scattering, and even when an electric field is applied, it does not completely clear,
There is a problem that an emulsion state remains. Therefore, such a dimming window cannot perform a display function by blocking and transmitting light, which is used as an operation principle in an existing liquid crystal display element. However, such problems can be solved by using the light control film according to the present invention.

Products using the light control film according to the present invention are used for partitioning indoors and outdoors, or window glasses for construction, various flat display elements used in the electronics industry and video equipment, various instrument panels, and existing liquid crystal display elements. , Optical shutters, various indoor / outdoor public notices and guide signs, automobile window glasses, rear-view mirrors, sunroofs, etc., and also applicable to eyeglasses, sunglasses, eyeglasses, etc.

The structure and operation of the light control film according to the present invention will be described in more detail with reference to the drawings.

FIG. 1 is a schematic structural view of a light control film according to one embodiment of the present invention, in which a film-like light control layer 1 is formed of two transparent substrates 6 coated with a transparent conductive thin film 5. It is sandwiched between the conductive substrates 4. By switching the switch 8, connection and disconnection between the power supply 7 and the two transparent conductive thin films 5 are performed. The film-like light control layer 1 is a film-like solid resin matrix 2 obtained by ultraviolet curing a silicone resin having a substituent having an ethylenically unsaturated bond.
And a liquid light polarization suspension dispersed in the form of droplets 3 in the solid resin matrix 2.

FIG. 2 is a view for explaining the operation of the light control film shown in FIG. 1, showing a case where the switch 8 is turned off and no electric field is applied. In this case, the incident light 11 is absorbed, scattered, or reflected by the particles 10 due to Brownian motion of the particles 10 dispersed in the dispersion medium 9 constituting the liquid droplets 3 of the liquid light polarization suspension. And cannot be transmitted. However, as shown in FIG. 3, when the switch 8 is connected and an electric field is applied, the incident light 11 passes between the arranged particles 10 because the particles 10 are arranged in parallel with the electric field formed by the applied electric field. I will be. In this way, a light transmission function without a reduction in scattering and transparency is provided.

[0037]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to Examples of the present invention and Comparative Examples thereof, but the present invention is not limited to these Examples.

(Production Example of Particles) In order to produce particles,
Dilute nitrocellulose 1/4 LIG (trade name, manufactured by Asahi Kasei Corporation) 15% by weight of isoamyl acetate (special reagent grade, manufactured by Wako Pure Chemical Industries, Ltd.) in a 500 ml four-necked flask equipped with a stirrer and a condenser. 87.54 g of solution, 44.96 g of isoamyl acetate, 4.5 g of dehydrated CaI ₂ (for chemical use, manufactured by Wako Pure Chemical Industries, Ltd.), and 2.0 g of absolute ethanol (for organic synthesis, manufactured by Wako Pure Chemical Industries, Ltd.) In a solution of 0.8 g of purified water (purified water, manufactured by Wako Pure Chemical Industries, Ltd.), 4.5 g of iodine (JIS reagent special grade, manufactured by Wako Pure Chemical Industries, Ltd.) is dissolved, and a substrate of light polarizing particles is dissolved. Pyrazin which is a forming substance
2,5-dicarboxylic acid dihydrate (PolyCarbon)
Industries) (3 g). After stirring at 45 ° C. for 3 hours to terminate the reaction, the mixture was stirred for 2 hours with an ultrasonic disperser.
Time dispersed. At this time, the hue of the mixture changed from brown to dark blue. Next, in order to take out light-polarized particles of a certain size from the reaction solution, the particles were separated using a centrifuge. The reaction solution was centrifuged at a speed of 750 G for 10 minutes to remove precipitates, and further centrifuged at 7400 G for 2 hours to remove suspended matters and collect precipitate particles. FIG. 4 shows the major axis, minor axis, and aspect ratio of the precipitate particles. The dichroic crystal had a major axis of 0.3 to 0.6 μm, an aspect ratio of 1.1 to 2.4, and an average aspect ratio of 1.84.

(Production Example of Light Polarized Suspension) 45.5 g of the light polarized particles obtained in the above (Production Example of Particles) was used as a dispersion medium in butyl acrylate (Wako Special Grade, Wako Pure Chemical Industries, Ltd.)
/ 2,2-trifluoroethyl acrylate (for industrial use, manufactured by Kyoeisha Chemical Industry Co., Ltd.) / 2-hydroxyethyl acrylate (Wako 1st grade, manufactured by Wako Pure Chemical Industries, Ltd.) copolymer (Monomer molar ratio: 19 / 1.5 / 0.5, weight average molecular weight: 2,000) and 50 g with a stirrer.
Mix for 0 minutes. Then, isoamyl acetate was removed under reduced pressure at 133 ° C. for 3 hours using a rotary evaporator under a vacuum of 133 Pa to produce a stable liquid light-polarized suspension without particle sedimentation and aggregation.

(Example of producing UV-curable silicone resin)
In a four-necked flask equipped with a Dean-Stark trap, a condenser, a stirrer, and a heating device, both ends silanol polydimethylsiloxane (reagent, Chisso Corporation) 60.33
g, both ends silanol polydimethyldiphenylsiloxane (reagent, Chisso Corp.) 159.18 g, (3-acryloxypropyl) methyldimethoxysilane (reagent,
20.54 g (manufactured by Chisso Corporation) and 3.08 g of an organotin-based catalyst 2-ethylhexanetin (manufactured by Wako Pure Chemical Industries, Ltd.) were charged and refluxed at 101 ° C. for 5 hours to carry out a reaction. Next, 54.43 g of trimethylethoxysilane (reagent, manufactured by Chisso Corporation) was added, refluxed for 3 hours, a dealcoholization reaction was performed, and the weight average molecular weight was 70,00.
Thus, a UV-curable silicone resin (silicone resin having a substituent having an ethylenically unsaturated bond) was obtained.

Example 1 10 g of the ultraviolet-curable silicone resin obtained in (Production example of ultraviolet-curable silicone resin), bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide (Ciba. To 0.1 g of Specialty Chemicals Co., Ltd.) and 0.3 g of dibutyltin dilaurate as a coloring inhibitor, 2.5 g of the light-polarized suspension obtained in (Production Example of Light-Polarized Suspension) was added. The mixture was mechanically mixed for 1 minute to produce a light control material. This light control material is
O (indium tin oxide) transparent conductive film (thickness 300)
Å) coated with a surface electric resistance of 200
~ 300Ω polyester film (Tetraite TC
F, coated on a transparent conductive substrate made of Oike Industry Co., Ltd., having a thickness of 125 μm), and irradiated with ultraviolet light of 5000 mJ / cm ² under a nitrogen atmosphere using a high-pressure mercury lamp to obtain a light-polarized suspension. Produced a light control layer in the form of a film dispersed and formed in an ultraviolet-cured silicone resin as spherical droplets. On this film, a transparent conductive substrate having a film-like light control layer produced in the same manner, a light control layer is superposed, and a transparent electrode is disposed on the opposite surface.
Was manufactured. The size of the droplet of the light-polarized light suspension in the light control film was 2 μm on average as a value of the diameter of the droplet measured by an optical microscope. The total light transmittance was 6.6% when no AC voltage was applied. Also, 400
When an AC voltage of 50 Hz was applied, the total light transmittance was as good as 87.5%.

Example 2 A light control film was produced in the same manner as in Example 1 except that the amount of the light polarization suspension was changed from 2.5 g to 5 g. The size of the droplet of the light polarization suspension in the light control film is an average of 5 droplet diameter values measured with an optical microscope.
μm. The total light transmittance was 4.4% when no AC voltage was applied. When a 50 Hz AC voltage of 400 Hz was applied, the total light transmittance was 85.6%.
And was good.

Example 3 Instead of the light polarizing particles used in Example 1, the volume average diameter measured by N4MD (manufactured by Beckman Coulter, Inc.) was 0.1.
48 μm, and the range of the aspect ratio is 2.0 to 3.5.
The light control was performed in the same manner as in Example 1 except that carbon fibers (trade name: Glasca 0.2 GWH, manufactured by Nikkiso Co., Ltd.) having an average aspect ratio of 3.0 were used. A film was produced. The size of the droplet of the light-polarized light suspension in the light control film was 2 μm on average as a value of the diameter of the droplet measured by an optical microscope. The total light transmittance was 2.9% when no AC voltage was applied. In addition, 400Hz 5
When an AC voltage of 0 V was applied, the total light transmittance was 8
It was as good as 3.2%.

Example 4 Instead of the light-polarizing particles used in Example 1, the volume average diameter measured by N4MD (manufactured by Beckman Coulter, Inc.) was 0.1%.
The same processing as in Example 1 except that a τ-type metal-free phthalocyanine having a thickness of 3 μm, an aspect ratio of 1.6 to 2.0, and an average aspect ratio of 1.8 was used. Thus, a light control film was manufactured. The size of the droplet of the light-polarizing suspension in the light control film was 2.5 μm on average as a value of the diameter of the droplet measured by an optical microscope. The transmittance is
When no AC voltage was applied, it was 5.2%. Also,
When a 50 V AC voltage of 400 Hz was applied, the total light transmittance was as good as 83.1%.

Comparative Example 1 Polymethacrylic acid (weight average molecular weight: 30,000) was used instead of the ultraviolet-curable silicone resin used in Example 1.
Using 10 g of a 20% by weight toluene solution, 0.3 g of dibutyltin dilaurate and 6.1 g of the light-polarizing suspension obtained in (Production example of light-polarizing suspension) were added, and mechanically mixed with a homogenizer for 1 minute. Then, defoaming was performed to produce a light control material. A polyester film having a surface electric resistance of 200 to 300Ω (Tetrite TCF, manufactured by Oike Kogyo Co., Ltd.) coated with a transparent conductive film of ITO (indium tin oxide) (800 mm thick) 125 μm)
Applied on a transparent conductive film of a transparent conductive substrate made of
The solvent was volatilized at ℃ to form a film. Another transparent conductive substrate was overlaid on this film to produce a light control film. The thickness of the light control layer was 60 μm, and the size of the droplet of the light polarization suspension in the light control film was 5 μm on average as the value of the diameter of the liquid droplet measured by an optical microscope. The transmittance is
When no AC voltage was applied, it was 5.3%. Also,
When an AC voltage of 400 Hz and 50 V was applied, the total light transmittance was 13.0%, which was smaller than that of Examples 1 to 4.

Comparative Example 2 A light control film was prepared by treating in the same manner as in Example 1 except that a τ-type metal-free phthalocyanine having an aspect ratio of 1 was used instead of the light polarizing particles used in Example 1. Manufactured. The size of the droplet of the light polarization suspension in the light control film is
2.5 μm on average as the value of the diameter of the droplet measured with an optical microscope
Met. The transmittance is 5. when no AC voltage is applied.
2%. Further, when an alternating voltage of 50 Hz of 400 Hz was applied, the total light transmittance was 10%, and Examples 1 to 4 were used.
Was smaller than.

Comparative Example 3 A light control film was prepared in the same manner as in Example 1 except that the ε-copper-type metal-free phthalocyanine having an aspect ratio of 5 was used instead of the light polarizing particles used in Example 1. Was manufactured. The size of the droplet of the light polarization suspension in the light control film is
2.5 μm on average as the value of the diameter of the droplet measured with an optical microscope
Met. The transmittance is 2. when no AC voltage is applied.
2%. Further, when an alternating voltage of 400 V and 50 V was applied, the total light transmittance was 15%, and Examples 1 to 4 were used.
Was smaller than.

[0048]

By using the light control material of the present invention,
Because there is no change in the transparent conductive substrate interval, there is no local hue change due to the change in the substrate interval, and there is no risk of leakage of the light control material due to the destruction of the sealing material between the transparent conductive substrates, and A light control film exhibiting a constant response time over the entire surface can be manufactured.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of one embodiment of the light control film of the present invention.

FIG. 2 is a schematic view for explaining an operation of the light control film of FIG. 1 when no electric field is applied.

FIG. 3 is a schematic diagram for explaining an operation of the light control film of FIG. 1 when an electric field is applied.

FIG. 4 is a graph showing the major axis, minor axis, and aspect ratio of the particles used in the production examples of the particles of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Film-like light control layer 2 Solid resin matrix 3 Droplet 4 Transparent conductive substrate 5 Conductive thin film 6 Transparent substrate 7 Power supply 8 Switch 9 Dispersion medium 10 Particle 11 Incident light

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08J 5/18 CFH C08J 5/18 CFH C08K 5/34 C08K 5/34 C08L 33/16 C08L 33/16 83 / 07 83/07 G02F 1/061 501 G02F 1/061 501 F-term (reference) 2H079 AA02 AA13 BA01 CA21 CA24 DA07 EA13 EB17 4F071 AA33 AA67 AC12 AC19 AE09 AF29 AH03 AH19 BA06 BC02 4J002 GP01 GP01 EU04 BG08X PA69 PB06 PB25 PB40 PC02 PC08 QB25 SA01 SA06 SA16 SA51 SA54 SA84 TA03 TA06 TA09 UA01 VA01 VA05 WA10 4J027 AF05 CA03 CA25 CA34 CA36 CB10 CC05 CD04

Claims (7)

[Claims] 1. A polymer medium comprising a silicone resin having a substituent having an ethylenically unsaturated bond and a photopolymerization initiator, wherein the polymer medium is cured by irradiation with ultraviolet light,
An optically polarized suspension in which particles having an aspect ratio of 1.1 to 4.0 are dispersed in a flowable state in a flowable state, wherein the dispersion medium in the optically polarized suspension is a polymer medium; A light modulating material that can be phase-separated from the cured product. 2. The light modulating material according to claim 1, wherein the dispersion medium in the light polarization suspension has incompatibility or partial compatibility with the polymer medium. 3. The light modulating material according to claim 1, wherein the particles in the light polarization suspension are dichroic crystals. 4. The light modulating material according to claim 1, wherein the dispersion medium in the light polarization suspension is an acrylic ester oligomer having a fluoro group and a hydroxyl group. 5. A light control film formed using the light control material according to claim 1, wherein the light control film is a solid resin matrix formed from a polymer medium, and a light dispersed in the solid resin matrix. A light control film having a light control layer comprising a polarizing suspension. 6. The light control film according to claim 5, wherein the light control layer is sandwiched between two transparent conductive substrates. 7. The light modulating material according to claim 1 is coated on a transparent conductive substrate, and the silicone resin is cured by irradiating ultraviolet rays to form a light modulating layer, and a transparent conductive material is formed on the light modulating layer. A method for producing a light control film, comprising bringing a substrate into close contact.