JPH046514A - High-polymer composite film and light control element containing this film - Google Patents

Abstract

PURPOSE:To allow the formation of thinner films in a wider area with increased freedom in shape, etc., by incorporating a suspension contg. particles sensitive to electric fields into the holes of a porous high-polymer film. CONSTITUTION:The suspension contg. the particles sensitive to the electric fields are incorporated into the holes of the porous high-polymer film. The particles sensitive to the electric fields to be incorporated in the suspension may be in the form of any of a ball, needle, bar or flake and is more preferably in the form of the flake. The use ratio of the particles sensitive to the electric fields incorporated in the suspension is preferably from 0.05 wt.% to a range where the particles do not cause flocculation, settlement, etc. Any high polymers are usable as the high polymer to be used for the porous high-polymer film, insofar as the high polymers can form the composite film with the suspension contg. the particles sensitive to the electric fields. The holes of the porous high-polymer film have preferably about 0.5 to 500mum hole size and the film having >=400 pieces/cm<2> density of the holes is preferably used. The higher density is more preferable. The formation of the thinner films in the wider area with the increased freedom in shape, etc. is possible in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a polymer composite film and a light control element containing the same.

(Prior Art and Problems to be Solved by the Invention) One of the characteristics of a suspension containing particles that are sensitive to an electric field is that when an electric field is applied, the suspended particles aggregate or align, and in this state,
Light passes through the suspension, and the suspension itself appears transparent, and when the electric field is removed, the particles return to a non-oriented random state due to Brownian motion, resulting in low light transmission. Sometimes it is possible to adjust.

For this reason, dimming devices using suspensions that are sensitive to electric fields have been proposed for display devices, dimming windows, mirrors, etc.
-144895, JP-A-464464, etc.). However, the suspension liquid has fluidity, and there are currently problems in terms of fixing the device structure, increasing the area, and freeing the shape.

(Means for solving problems) The present invention solves the above-mentioned problems.

That is, the present invention provides a polymer composite membrane characterized by containing a suspension containing particles sensitive to an electric field in the pores of a porous polymer membrane, and at least the above polymer composite membrane. The gist of the invention is a light control element that is constructed by being sandwiched between a pair of substrates, one of which is transparent and has an electrode formed on its inner surface.

The present invention will be explained in detail below.

The electric field-sensitive particles contained in the suspension used in the present invention may be spherical, needle-shaped, rod-shaped, or flake-shaped; however, for the purpose of blocking light, acicular, rod-shaped,
Flaky ones are best.

For example, herabasite (quinine iodosulfate), graite, mica, garnet, aluminum, optimized products of sulfate alkaloids (alkaloids include dihydrocinchonidine, cinchonidine, dihydroquinine, cinchonine, dihydroquinconine, etc.), etc. The particle size thereof is preferably one in which the major axis is 100 μm or less.

The solvent used for the suspension may be any solvent that does not dissolve or decompose the particles, and is selected depending on the type of particles. For example, aromatic solvents such as benzene, toluene, chlorobenzene, and cyclohexylbenzene; ester solvents such as ethyl acetate, di-n-butyl oxalate, isoamyl benzoate, dioctyl phthalate, phenyl acetate, paracresyl acetate; -Hydrocarbon solvents such as hexane, cyclohexane, n-octane, n-decane, n-dodecane, and paraffin; halogen solvents such as chloroform, trichloroethane, tetrachloroethane, tetrachlorethylene, and tetrachromoethane; n-hexanol, Cyclohexanol, 1-octatool,
Alcohol solvents such as 2-decanol; ether solvents such as di-n-butyl ether and dimethoxyethane; ketone solvents such as methyl ethyl ketone, di-n-butyl ketone, and cyclohexanone. Furthermore, liquid crystals such as nematic liquid crystals, smectic liquid crystals, and cholesteric liquid crystals may be used as the suspending medium.

These solvents may be used alone or in appropriate combinations.

The proportion of particles sensitive to electric fields contained in the suspension is preferably within a range of 0.05% by weight to 0.05% by weight so that the particles do not cause aggregation or sedimentation. At this time, a dispersion stabilizer may be added to prevent particle agglomeration, sedimentation, etc.

Examples of the dispersion stabilizer include those that can be used as dispersion stabilizers for pigments, such as nitrocellulose, polyvinyl butyral, acrylic acid copolymers, nonionic, cationic, or anionic surfactants.

As the polymer used for the porous polymer membrane, any polymer can be used as long as it can form a composite membrane with a suspension containing particles sensitive to an electric field.

Specific polymers include vinyl compounds and addition polymers of vinyl compounds such as polyethylene, polyacrylic acid, polymethyl acrylate, polyvinyl acetate, polyacrylonitrile, polyvinyl chloride, and polyvinyl fluoride, polymethacrylic acid, and polymethacrylic acid. Methyl acid, polyethyl methacrylate, polyvinylidene chloride, polyvinylidene fluoride, vinylidene cyanide, vinylidene fluoride/trifluoroethylene copolymer, vinylidene fluoride/tetrafluoroethylene copolymer, vinylidene cyanide/vinyl acetate Copolymers of vinyl compounds such as copolymers or fluorine-based compounds, compounds containing fluorine such as polytrifluoroethylene, polytetrafluoroethylene, polyfluoropropylene, polyamides such as nylon 6 and nylon 66, polyimides, Polyurethane, polypeptide, polyester such as polyethylene terephthalate, polycarbonate,
Examples include polyethers such as polyoxymethylene, polyethylene oxide, and polypropylene oxide.

The polymer can be used alone or in a mixed system in which various polymers are combined.

Moreover, the pore diameter of the pores of the porous polymer membrane in the present invention is 0.
．． It is preferably about 5 to 500 μm, and the density of the pores is preferably 400 pores/Cl11'' or more, and the higher the density, the more preferable it is.

Further, the pore diameter of the porous polymer membrane used must be larger than that of the particles used, and it is more preferable that the difference is larger.

The method for producing a polymer composite membrane containing an electric field-sensitive suspension in the pores of a porous polymer membrane is as follows: (1) Preparing a porous polymer membrane in advance, and then Method of filling the pores with a suspension (2) Mixing the suspension on the polymer raw material and polymerizing the raw material to form a porous polymer membrane, while filling the pores with the suspension. Method of filling the pores with a suspension (3) There are methods such as uniformly mixing the polymer solution and the suspension and evaporating the solvent in which the polymer was dissolved, which method is selected as appropriate.

In particular, in the case of method (1), many methods for producing porous polymer membranes have been disclosed, and can be classified into a) method of mechanically making holes with a needle, etc. b) salt elution method C) solvent volatilization method d) Solvent substitution method e) Emulsion method f) Radiation irradiation method g) Stretching method h) Sintering method i) Method of adding fillers to the polymer and eluting them.

The polymer composite membrane of the present invention can be produced by bringing an electric field-sensitive suspension into contact with the entire surface of the porous polymer membrane by coating, or by immersing the porous polymer membrane in the suspension. can be obtained by impregnating the suspension into the pores of a porous polymer membrane.

The light control element of the present invention can be adjusted by forming the polymer composite film of the present invention as described above and then sandwiching it between a pair of substrates, at least one of which is transparent and has an electrode formed on the inner surface. Create optical elements.

A transparent electrode such as ITO is used as the electrode, and a transparent substrate such as a glass or a plastic plate such as polyester can be used as the electrode substrate.

When using a pair of electrode substrates that are both transparent, it can be used as a transmission type dimming element, and when using a pair of electrode substrates where one is transparent and the other is opaque, a reflective layer is added after the opaque electrode substrate. By placing , it can be used as a reflective dimming element.

The light control element according to the present invention can be used in devices that utilize transmission or reflection of light, such as display devices, light control windows, mirrors, sunglasses, and memories.

〔Example〕

EXAMPLES Next, the present invention will be specifically explained with reference to examples, but the present invention is not limited to the following examples.

Example 1 Polyethylene porous membrane manufactured by Tredegar (NαX6463)
JP-A-53-144893, Example 2 on the surface of
A suspension containing polarizing particles of dihydrocinchonidine sulfate periodide (using phenylacetate as a suspending solvent, solid content: 2.7 wt%) prepared according to the method described in 1. It was infiltrated into the pores to form a polymer composite membrane. Both sides of the polymer composite membrane are coated with ITO.
A light control element was formed by sandwiching the electrodes with attached glass electrodes (resistance: 100Ω) with the electrodes facing inside. IOV, 25V, 50V for this element
, 10. When OV and voltage were sequentially applied, as shown in Figure 1 (the element, which was blue before voltage application, became completely transparent at 100V.
Looking at the wavelength of nm, even at IOV, the absorbance has changed to 67% compared to the case of 100 square meters, and it can be driven at a low voltage.

Example 2 A suspension containing polarizing particles was prepared in the same manner as in Example 1 in the pores of a polyethylene porous membrane (kX6463) manufactured by Tredegar (equal amounts of dioctyl phthalate and phenylacetate were mixed as a suspending solvent). (using liquid) to form a polymer composite membrane.

Polyester membrane electrodes with ITO were attached to both sides of the cough polymer composite membrane (
A light control element was formed by sandwiching the light control element with a resistance of 250Ω) with the electrode facing inside.

When a voltage of 100 V was applied to this device, it showed the same change in absorbance as in Example 1.

Example 3 Polyethylene porous membrane manufactured by Smith & Nephew (KiP620)
) A suspension containing polarizing particles of dihydroquinicine periodide sulfate (using a mixture of equal amounts of dioctyl phthalate and chlorobenzene as the suspension solvent, solid content 3.0 wt)
%) to form a polymer composite membrane.

Polyester membrane electrodes with ITO are connected to both sides of the polymer composite membrane (
A light control element was formed by sandwiching the light control element with a resistance of 250Ω) with the electrode facing inside.

When a voltage of 100 μ was applied to this device, it showed the same change in absorbance as in Example 1.

(Effects of the Invention) The polymer composite film obtained by the present invention can be made thinner, wider in area, and more flexible in shape. Useful for windows, mirrors, memories, etc.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the electric field response of a light control element manufactured using the polymer composite film of the present invention obtained in Example 1. From top: OV, IOV, 25V, 50V, 100
It shows the absorbance when V was applied. In the figure, the vertical axis represents absorbance, and the horizontal axis represents wavelength (no,).

Claims (2)

[Claims] (1) A polymer composite membrane characterized by containing a suspension containing particles sensitive to an electric field in the pores of a porous polymer membrane. (2) A light control element comprising the polymer composite film according to claim 1 sandwiched between a pair of substrates, at least one of which is transparent and has an electrode formed on its inner surface.