JP2002082364A - Light regulation material, light regulation film and method for manufacturing the light regulation film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light controllable film, which allows the adjustment of the entire incident light quantity, obviates coagulation and settlement of light polarizing particles, obviates local hue changes by a change in inter-substrate spacings, obviates the possibility of the leakage of the light regulated material caused by destroying the sealing material between the substrates, exhibits the specified response time over the entire surface and has superior durability with respect to UV rays. SOLUTION: A light regulation layer is formed on the light regulation film having the light regulation layer, consisting of a solid resin matrix and the light polarizing suspension dispersed into the solid resin matrix by irradiating the light regulation material which contains a high-polymer medium, containing a high polymer having a substituent possessing an ethylenically unsaturated bond and an acryl phosphine oxide-base phtopolymerization initiator and cured through irradiation with UV rays, and the light polarizing suspension dispersed in the dispersion medium in the flowable state of the particles and of which the dispersion medium in the light polarizing suspension can be phase separated from the high-polymer medium and its cured matter with the UV rays, thereby curing the high polymer which has the substituent possessing the ethylenically unsaturated bond.

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 light control window using the light control glass having the above-described 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 of the substrates due to wind pressure, resulting in a change in optical density and inhomogeneous hues, or the destruction of the surrounding sealant for collecting liquid between 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 interface of the capsule 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 directions different from each other at the interface of the other capsule, so that the dimming window becomes translucent milky white. 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 liquid crystal into a 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 provides a light control film, a method of manufacturing the same, and a light control material used therefor, in which a decrease in the tunability of the light polarizing particles due to an electric field is reduced, and furthermore, the stability, especially the durability against ultraviolet rays, is excellent. The purpose is to:

[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 polymer having a substituent having an ethylenically unsaturated bond and an acylphosphine oxide-based photopolymerization initiator, which is cured by irradiation with ultraviolet light; A light-polarizing suspension dispersed in a dispersion medium in a possible state, wherein the dispersion medium in the light-polarization suspension is capable of phase-separating from a polymer medium and a cured product thereof. (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) The light modulating material according to any one of (1) to (4), wherein the acylphosphine oxide-based photopolymerization initiator is a compound represented by the following general formula.

Embedded image (Wherein R ¹ is a phenyl group or a substituted phenyl group,
R ² represents an oxyalkyl group having 1 to 5 carbon atoms, a phenyl group or a substituted phenyl group, and R ³ represents a phenyl group, a substituted phenyl group, a benzoyl group or a substituted benzoyl group. (6) A light control film formed using the light control material according to any one of (1) to (5), wherein the light control film is dispersed in a solid resin matrix formed from a polymer medium and a solid resin matrix. A light control film having a light control layer comprising a light polarization suspension. (7) The light control film according to (6), wherein the light control layer is sandwiched between two transparent conductive substrates. (8) The light modulating material according to (1) is applied on a transparent conductive substrate, and the polymer medium 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, comprising:

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The light modulating material of the present invention is a polymer having a substituent having an ethylenically unsaturated bond (hereinafter referred to as “UV”).
Curable resin ") and an acylphosphine oxide-based photopolymerization initiator, a polymer medium which is cured by irradiation with ultraviolet light, and particles dispersed in a dispersion medium in a flowable state. And a dispersion medium in the light polarization suspension, which is capable of phase-separating from a polymer medium and a cured product thereof. 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 breakage 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 UV-curable resin and (B) an acylphosphine oxide-based photopolymerization initiator, and is cured by irradiation with ultraviolet rays.

Examples of the UV-curable resin in the present invention include silanol polysiloxanes at both ends, such as silanol polydimethylsiloxane at both ends, silanol polydiphenylsiloxane-polydimethylsiloxane copolymer at both ends, and silanol polydiphenylsiloxane at both ends.
Dehydrocondensation of trialkylalkoxysilanes such as trimethylethoxysilane and ethylenically unsaturated bond-containing silane compounds such as (3-acryloxypropyl) methyldimethoxysilane in the presence of organometallic catalysts such as tin and titanium A silicone resin synthesized by a reaction and a dealcoholization reaction is preferably used. As a form of the UV curable resin, a solventless type is preferably used. That is, when a solvent is used for synthesizing the UV curable resin, it is preferable to remove the solvent after the synthesis reaction. These UV
The weight average molecular weight in terms of polystyrene obtained by gel permeation chromatography of the cured resin is
Preferably from 20,000 to 100,000,
More preferably, it is 30,000 to 80,000. What is the amount of the ethylenically unsaturated bond-containing silane compound such as (3-acryloxypropyl) methyldimethoxysilane used? 2 to 30 of total amount of raw material siloxane and silane compound
% By weight, more preferably 5 to 18% by weight.

As the acylphosphine oxide-based photopolymerization initiator in the present invention, a compound represented by the aforementioned general formula [Chemical Formula 1] is preferable. In the above general formula, R ¹ , R ²
And the substituted phenyl group or substituted benzoyl group described as R ³ include those substituted with one or more halogen atoms, alkyl groups and the like, and among them, alkyl having 1 to 5 carbon atoms is preferable. Those substituted with a group are preferred. Examples of the acylphosphine oxide-based photopolymerization initiator represented by the general formula include bis (2,
4,6-trimethylbenzoyl) phenylphosphine oxide, diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide, 2,4,6-trimethylbenzoylethoxyphenylphosphine oxide, benzoylmethoxy (4-methylphenyl) phosphine Fin oxide and the like can be used. The amount of the acylphosphine oxide-based photopolymerization initiator to be used is preferably 0.5 to 10 parts by weight, more preferably 1 to 5 parts by weight, based on 100 parts by weight of the above-mentioned UV curable resin.

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

Further, an additive such as a coloring inhibitor such as dibutyltin dilaurate may be added to the polymer medium as needed.

The dispersion medium in the light-polarized suspension used in the above-mentioned combination serves as a dispersion medium in the light-polarized suspension, and is selectively adhered and coated on particles to form a polymer medium. It is preferable to use a liquid copolymer which acts so that particles move to the phase-separated droplet phase at the time of phase separation, has no electric conductivity, and has no affinity for a polymer medium. 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, either a fluoro group or a hydroxyl group, faces the light-polarizing particle, and the remaining monomer units work to maintain the light-polarizing suspension as droplets in the polymer medium. The light-polarized particles are very homogeneously dispersed in the suspension and during the phase separation the light-polarized particles are guided into the droplets to be 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, 5-trimethylhexyl / 2-hydroxypropyl acrylate / fumaric acid copolymer, butyl acrylate / 2-hydroxyethyl acrylate copolymer, 2,2,3,3-tetrafluoropropyl acrylate / butyl acrylate / 2-hydroxyethyl acrylate copolymer, 1H, 1H, 5H-octafluoropentyl acrylate / butyl acrylate / 2-hydroxyethyl acrylate copolymer, 1H, 1H, 2H acrylate
2H-heptadecafluorodecyl / butyl acrylate /
2-hydroxyethyl acrylate copolymer, 2,2,2-trifluoroethyl methacrylate / 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 methacrylate
-Heptadecafluorodecyl / butyl acrylate / 2-hydroxyethyl acrylate copolymer and the like.
More preferably, it has both a fluoro group and a hydroxyl group. These acrylate oligomers have a weight average molecular weight in terms of standard polystyrene measured by gel permeation chromatography of 1,000 to 20,000.
00, preferably 2,000 to 10,000
Is more preferable. The amount of the fluoro group-containing monomer used as a raw material of these acrylate 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 acrylate oligomers is preferably 0.5 to 22.0 mol%, more preferably 1 to 8 mol%. If the amount of the hydroxyl group-containing monomer exceeds 22.0 mol%, the refractive index tends to increase, and the light transmittance tends to decrease.

The light-polarizing suspension used in the present invention is a dispersion in which particles are fluidly dispersed in a dispersion medium. As the particles, for example, a polymer medium, or a resin component in the polymer medium, that is, having no affinity with the above-described UV-curable resin, and in the presence of a polymer dispersant capable of enhancing the dispersibility of the particles, Is a precursor (substrate forming substance) of
2,3-dicarboxylic acid dihydrate, pyrazine-2,5-
Needle of polyperiodide prepared by reacting one substance selected from the group consisting of dicarboxylic acid dihydrate and pyridine-2,5-dicarboxylic acid monohydrate with iodine and iodide Small crystals 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, for example, the following general formula: CaI ₂ (C ₆ H ₄ N ₂ O ₄ ) .XH ₂ O (X: 1 to
2) Those represented by:

Further, US Pat. No. 2,041,138 (E.R.
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 polarizing 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 UV curable resin in a polymer medium, particles are formed into fine droplets formed by phase separation during film production. It easily disperses and floats, resulting in excellent variable capacity.

In addition to the particles described above, 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,
Nickel, iron, cobalt, chromium, titanium, beryllium, molybdenum, tungsten, aluminum, chromium and the like can be mentioned.

[0021]

Embedded image (In the formula, M represents a central metal or H _2. ) In the present invention, the particle size (volume average particle by photon correlation spectroscopy measured with a submicron analyzer (for example, N4MD (manufactured by Beckman Coulter, Inc.)) Diameter value)
Is preferably 1 μm or less, more preferably 0.1 to 1 μm, and particularly preferably 0.1 to 0.5 μm. 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 polarizing 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 contains a light polarizing suspension in an amount of usually 1 to 100 parts by weight, based on 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 water, 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 a light polarization suspension containing particles is dispersed in a UV-curable resin or a solution thereof in the form of droplets. A light control film can be suitably manufactured by forming a light control layer by coating on the substrate, irradiating ultraviolet rays to cure the UV curable resin, and bringing the transparent conductive substrate into close contact with the light control layer. . The amount of the light polarization suspension in the light control material of the present invention is 1 to 1 with respect to 100 parts by weight of the UV curable resin.
The amount is preferably 00 parts by weight, more preferably 4 to 70 parts by weight, further preferably 8 to 60 parts by weight, further preferably 8 to 50 parts by weight. In addition, the amount of the photopolymerization initiator is 100
The amount is preferably from 0.5 to 10 parts by weight, more preferably from 1 to 5 parts by weight, based on parts by weight. First,
The liquid light polarization suspension is homogeneously mixed with a UV-curable resin (or a solution thereof) and a polymer medium containing a photopolymerization initiator, and the light-polarized suspension is mixed with the UV-curable resin or a solution thereof. The mixture is dispersed in a droplet state. This mixed solution is applied on a transparent conductive substrate in a constant thickness, and after drying and removing the solvent as necessary, the mixture is irradiated with ultraviolet rays using a high-pressure mercury lamp or the like,
The UV curing resin is cured. As a result, a film in which the liquid light polarization suspension is dispersed in the form of droplets in the solid resin matrix composed of the cured product of the UV cured resin is obtained.
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 μm is preferable, and 20 to 100 μm is more preferable.

The size of the droplet of the light-polarized light 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 achieved by matching the refractive index of the liquid light polarization suspension with the refractive index of the UV curable resin. The power supply used is AC, 10-100 volts (effective value), 30Hz-500
It can operate in the frequency range of kHz. The response time to the electric field is within 1 to 50 seconds at the time of decoloration, and 1 time at the time of coloring.
以内 100 seconds or less. UV durability shows stable variable characteristics even after 300 hours have passed, as a result of an ultraviolet irradiation test using a near ultraviolet lamp or the like.
It was found that even when left for a long time, the initial variable characteristics were maintained.

The transparent conductive substrate used when manufacturing 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 the paragraph phenomenon that occurs due to the small distance between the substrates and the 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 deterioration of the dimming material due to the destruction of the sealing material between the transparent conductive substrates 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 glass for architecture, 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 composed 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, and shows 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.

[0036]

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 grade reagent, 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 the 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 0.6 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.) was dissolved, and pyrazine-2,5 was dissolved. -3 g of dicarboxylic acid dihydrate
Was added. After stirring at 45 ° C. for 3 hours to terminate the reaction, the mixture was dispersed with an ultrasonic disperser for 2 hours. 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. 750G reaction solution
The precipitate was removed by centrifugation at a speed of 10 minutes for 10 minutes, and further centrifuged at 7390 G for 2 hours to remove suspended matter.
The precipitate particles were collected. The precipitate particles were dichroic crystals having a particle size of 0.3 to 0.6 μm as measured with a submicron particle analyzer (N4MD, manufactured by Beckman Coulter, Inc.).

(Production Example of Light Polarizing Suspension) 45.5 g of the light polarizing particles obtained in the above (Production Example of Particles) was converted into butyl acrylate (Wako Special Grade, Wako Pure Chemical Industries, Ltd.) as a dispersion medium.
/ 2,2-trifluoroethyl methacrylate (for industrial use, manufactured by Kyoeisha Chemical Industry Co., Ltd.) / 2-acrylic acid
Hydroxyethyl (Wako Class 1, Wako Pure Chemical Industries, Ltd.)
Copolymer (monomer molar ratio: 18 / 1.5 / 0.5, weight average molecular weight: 2,000, refractive index 1.4519) 50
g and mixed with a stirrer for 30 minutes. Then, isoamyl acetate was added to 133 using a rotary evaporator.
Vacuum was removed under reduced pressure at 80 ° C. for 3 hours under a vacuum of Pa to produce a stable liquid light-polarized suspension without particle sedimentation and aggregation.
As a result of measuring the optical characteristics of this light polarization suspension,
Under the conditions of 0 V and 400 Hz, at 700 nm, the light transmittance at the time of decolorization is 60 to 85%, and the light transmittance at the time of coloring is 0.3 to 1
The characteristics were 8%.

(Production Example of UV Cured Resin) In a four-necked flask equipped with a Dean-Stark trap, a cooling tube, a stirrer, and a heating device, 11.75 g of silanol polydimethylsiloxane at both ends (reagent, manufactured by Chisso Corporation) was added. 28 g of silanol polydimethyldiphenylsiloxane at both ends (reagent, manufactured by Chisso Corporation), 4 g of (3-acryloxypropyl) methyldimethoxysilane (reagent, manufactured by Chisso Corporation),
2-Ethylhexanetin (reagent, manufactured by Chisso Corporation) 0.2
g was charged and refluxed at 100 ° C. for 1 hour in heptane to carry out a reaction. Next, 10.6 g of trimethylethoxysilane (reagent, manufactured by Chisso Corporation) was added, and 30
And a heptane was removed under reduced pressure at 133 ° C. under a vacuum of 133 Pa for 3 hours using a rotary evaporator for 3 hours to obtain a weight average molecular weight of 60,00.
Thus, an ultraviolet-curable silicone resin (silicone resin having a substituent having an ethylenically unsaturated bond) having a refractive index of 1.4518 was obtained.

Example 1 10 g of the UV-curable silicone resin obtained in (Production Example of UV-curable resin), and ethyl 2,4,6-trimethylbenzoylphenylphosphinate (2,
4,6-trimethylbenzoylethoxyphenylphosphine oxide, LUCIRIN TPO-L, BAS
2.5 g of the light-polarized light suspension obtained in the above (Example of manufacturing a light-polarized light suspension) was added to 0.3 g of dibutyltin dilaurate (manufactured by Company F) and 0.3 g of dibutyltin dilaurate as a coloring inhibitor. And a light modulating material was produced. This light modulating material is coated with a transparent conductive film (thickness 300 mm) of ITO (indium tin oxide) and has a surface electric resistance of 200 to 30.
It is applied on a transparent conductive substrate made of a 0Ω polyester film (Tetraite TCF, manufactured by Oike Kogyo Co., Ltd., thickness 125 μm), and 3,000 mJ using a high-pressure mercury lamp.
/ Cm ² of UV light was applied to produce a film-like light control layer in which the light-polarized suspension was dispersed and formed in a UV-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 overlapped, and a light control film having a thickness of 70 μm in which a transparent electrode is disposed on the opposing surface is provided. Manufactured. The size of the droplet of the light polarization suspension in the light control film is 2 μm on average with the value of the diameter of the droplet measured by an optical microscope.
m. The transmittance was 5.7% when no AC voltage was applied. When a 50 V AC voltage of 400 Hz was applied, the visible light transmittance was 56.5%. The transmittance ratio was as large as 10 and good. Furthermore, a near-ultraviolet lamp (lamp intensity: 0.5 mW / c
(m ² , maximum energy wavelength: 369 nm) As a result of an ultraviolet irradiation test, even after irradiation for 300 hours, the transmittance ratio was hardly changed to 9.8, and no fading of the film was observed.

Example 2 A light control film was prepared in the same manner as in Example 1 except that the amount of the light-polarizing 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 transmittance was 4.8% when no AC voltage was applied. When a 50 V AC voltage of 400 Hz was applied, the visible light transmittance was 51.1%. The transmittance ratio was as large as 11 and good.

Example 3 Instead of the photopolymerization initiator used in Example 1, bis (2,2)
A light control film was manufactured by treating in the same manner as in Example 1 except that 4,6-trimethylbenzoyl) phenylphosphine oxide (IRGACURE 819, manufactured by Ciba Specialty Chemicals) was used. 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 transmittance was 4.4% when no AC voltage was applied.
In addition, when a 50 V AC voltage of 400 Hz was applied, the visible light transmittance was 53.1%. The transmittance ratio was as large as 12 and good. Further, as a result of an ultraviolet irradiation test using a near-ultraviolet lamp, even after irradiation for 300 hours, the transmittance ratio hardly changed to 11.7, and no fading of the film was observed.

Example 4 A light control film was produced in the same manner as in Example 3, 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 transmittance was 3.9% when no AC voltage was applied. When an AC voltage of 400 Hz and a voltage of 50 V was applied, the transmittance of visible light was 48.9%. The transmittance ratio was as large as 12.5, which was good.

Comparative Example 1 Instead of the photopolymerization initiator used in Example 1, 2-hydroxy-2-methyl-1-phenylpropan-1-one (D
A light control film was produced in the same manner as in Example 1 except that AROCUR 1173 (manufactured by Ciba Specialty Chemicals) was used. 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 transmittance was 5.6% when no AC voltage was applied. Also, 400
When an AC voltage of 50 Hz was applied, the transmittance of visible light was 55.7%. The transmittance ratio was as large as 10 and good. However, as a result of an ultraviolet irradiation test using a near-ultraviolet lamp, the transmittance ratio after irradiation for 100 hours was 3.
5, and the fading of the film was observed.

[0045]

By using the light control material of the present invention,
Because there is no change in the distance between the transparent conductive substrates, there is no local change in hue due to the change in the distance between the substrates, 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. A light control film exhibiting a constant response time, reducing the deterioration of the variable ability of the light-polarized particles due to an electric field, and exhibiting excellent stability, especially durability against ultraviolet rays, can be produced.

[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.

[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) B05D 7/24 303 B05D 7/24 303E C08F 2/50 C08F 2/50 299/00 299/00 F term ( 4D075 BB46Z DA04 DB31 DB48 DC02 DC24 DC38 EA10 EA21 EB22 EC37 4J011 QB25 SA84 UA01 VA02 4J027 AF05 CA03 CB10 CC05

Claims (8)

[Claims] 1. A polymer medium comprising a polymer having a substituent having an ethylenically unsaturated bond and an acylphosphine oxide-based photopolymerization initiator, the polymer medium being cured by irradiation with ultraviolet light, and particles. And a light polarization suspension dispersed in a dispersion medium in a flowable state, wherein the dispersion medium in the light polarization suspension is capable of phase separation from a polymer medium and a cured product thereof. material. 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. The acylphosphine oxide-based photopolymerization initiator is a compound represented by the following general formula.
The light control material according to any one of the above. Embedded image (Wherein R ¹ is a phenyl group or a substituted phenyl group,
R ² represents an oxyalkyl group having 1 to 5 carbon atoms, a phenyl group or a substituted phenyl group, and R ³ represents a phenyl group, a substituted phenyl group, a benzoyl group or a substituted benzoyl group. ) 6. 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. 7. The light control film according to claim 6, wherein the light control layer is sandwiched between two transparent conductive substrates. 8. The light modulating material according to claim 1 is coated on a transparent conductive substrate, and the polymer medium is cured by irradiating ultraviolet rays to form a light modulating layer, and the transparent conductive material is formed on the light modulating layer. A method for producing a light control film, comprising bringing a functional substrate into close contact.