JPH11184409A - Magnetophoretic display panel enclosing color magnetic particles - Google Patents

Abstract

(57) Abstract: Provided is a magnetophoretic display panel in which color magnetic particles are encapsulated and capable of performing color display. Kind Code: A1 Abstract: A magnetophoretic display panel in which a magnetic dispersion, a dispersion medium, a plastic dispersion liquid comprising a thickener and, if desired, a colorant is arranged between two substrates, the magnetic particles are light-reflective magnetic particles The light-reflective magnetic particles have a surface in which color magnetic particles colored with a daylight fluorescent coloring pigment or a daylight fluorescent dye are sealed using a binder.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetophoretic display panel capable of displaying and erasing a clear record by magnetism, and more particularly to a magnetophoretic display panel enclosing color magnetic particles.

[0002]

2. Description of the Related Art Conventionally, magnetic particles are moved by using a magnetic force to display an image. Two sheets of a plastic dispersion liquid containing a magnetic particle, a dispersion medium, a thickener, and a coloring material as desired are used. 2. Description of the Related Art A magnetophoretic display panel is known which is sealed in a small cell having a multi-cell structure formed by forming a small space between substrates, or provided with a microcapsule coating layer in which the plastic dispersion liquid is sealed. When recording with a head or the like in which a magnetic pen or electromagnet is arranged on the front side of the substrate, the magnetic particles attracted by the magnetic force of the magnetic pen, electromagnet, etc. migrate from the substrate on the back side and form a handwriting part. The display is formed by the difference in the color contrast of the non-handwriting portion. When the magnetic particles attracted to the front substrate are applied with a magnetic force from the back substrate by a magnetic eraser or the like, the magnetic particles are attracted to the back substrate and the displayed record can be erased. In general, a magnetophoretic display panel is used in applications such as a writing board or the like, in which dispersed magnetic particles are attracted by the magnetic force of a magnetic pen to obtain a display of characters and patterns as recorded. For example, it is used in various fields such as toys and stationery.

[0003]

However, in the above prior art, since the color of the magnetic particles is from black to dark brown, the handwriting portion is generally black to dark brown and the non-handwriting portion is white. However, in recent years, there has been a demand for a magnetophoretic display panel capable of color display.

An object of the present invention is to provide a magnetophoretic display panel capable of color display and enclosing color magnetic particles.

[0005]

According to the present invention, a plastic dispersion liquid comprising a magnetic particle, a dispersion medium, a thickener and optionally a colorant is disposed between two substrates. In the magnetophoretic display panel, the magnetic particles are light-reflective magnetic particles, and the surface of the light-reflective magnetic particles is colored with a daylight fluorescent pigment or a daylight fluorescent dye using a binder. The configuration is such that particles are enclosed.

[0006] In addition, a structure is used in which a binder is used on the surface of the light-reflective magnetic particles and colored with a white hiding agent and a daylight fluorescent pigment or a daylight fluorescent dye.

The surface of the light-reflective magnetic particles is coated with a white concealing agent using a binder and colored with a daylight fluorescent pigment or a daylight fluorescent dye.

Further, the surface of the light-reflective magnetic particles is colored with a daylight fluorescent pigment or a daylight fluorescent dye in a hollow shape.

[0009] The surface of the light-reflective magnetic particles may be colored with a daylight fluorescent pigment or a daylight fluorescent dye in a porous manner.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Light-reflective magnetic particles are selected from general ferromagnetic metal materials such as stainless steel, nickel steel and chromium steel, which have excellent light reflectivity. Can be. In addition, the size of the magnetic particles can be used depending on the purpose, from fine powder to coarse particles.However, if the size of the magnetic particles varies, the electrophoresis will vary, so by making them uniform, the electrophoresis will be stable and the display will be stable. Has a good effect on the sharpness of Further, the shape may be any shape such as a sphere, a column, a lump, a flake, etc., and is not particularly limited. Further, by coloring the surface of the magnetic particles in a hollow or porous shape, the apparent density of the magnetic particles can be reduced. Therefore, the magnetic particles are stable in the dispersion liquid. In addition, when the surface of the magnetic particles is colored, if the coloring is incomplete, a unique color of the magnetic particles appears. For this reason, even if the coloring is incomplete, if the light-reflective magnetic particles are used as the magnetic particles, the inherent color of the magnetic particles can be made inconspicuous by light reflection.

The daylight fluorescent pigments and daylight fluorescent dyes receive ultraviolet rays in sunlight and violet-blue-green rays in visible rays and emit fluorescent light of a longer wavelength than that of the pigments. Pigments and dyes that also have a color, that is, a reflection color, appear very bright because they almost match the wavelength of fluorescence, and have lightness three times or more as compared with ordinary coloring materials. The daylight fluorescent pigments are classified into a daylight fluorescent dye synthetic resin solid solution type and a pigment dye type.

As the binder, vinyl chloride resin, polyethylene resin, polypropylene resin, acrylic resin,
Phenol resin, epoxy resin, urethane resin, urea resin, melamine resin, alkyd resin, sulfonamide resin, maleic acid resin, ester gum, nitrocellulose
One or a mixture of two or more types of emulsions such as a common resin such as vinyl acetate resin or an acrylic copolymer resin can be used.

As the dispersion medium, preferably used are nonpolar solvents such as oils and aliphatic hydrocarbons, and polar solvents such as glycols and alcohols. Specifically, isoparaffin, spindle oil, ethylene glycol and the like are used. Particularly, an aliphatic hydrocarbon such as isoparaffin is preferable.

As the thickener, one or more of an inorganic thickener and an organic thickener can be selected and used alone or in combination in the plastic dispersion liquid. For example, a fatty acid bisamide having a hydroxyl group, specifically, ethylene bis-12-hydroxystearic acid amide, hydrogenated castor oil, or N-acylamino acid alkylamide such as N-lauroyl-L-glutamic acid-α, γ
-Di-n-butylamide or the like is used. One or two or more of these can be selected and used alone or in combination in the plastic dispersion liquid.

The difference in contrast between the handwriting portion and the non-handwriting portion can be recognized without blending a coloring material. However, in order to further enhance the contrast between the handwriting portion and the non-handwriting portion, it is necessary to use a white pigment or other pigment. A coloring material such as a dye or a pigment is blended.
Furthermore, 10% or less, preferably 3%, based on the plastic dispersion liquid.
% Is preferable because the display becomes clear. If the amount of the coloring material is too large, the display by the magnetic particles becomes unclear, and the contrast tends to decrease.

The color of the magnetic particles and the colorant of the plastic dispersion liquid may be any color as long as the color of the magnetic particles is different from black to dark brown and the colorant is different from the color of the magnetic particles. It is preferable to select an image having a large difference in saturation or lightness.

As the substrate, a transparent substrate is used for the front substrate, and either a transparent or opaque substrate may be used for the back substrate. Can display characters, patterns, and the like from both sides. In addition, the characters and patterns displayed on the front substrate can be read from the back surface by reversing the difference in color contrast between the plastic dispersion liquid and the magnetic particles. Similarly, when recording on the back substrate, it can be read from the front substrate.

In a first embodiment of the manufacture of a magnetophoretic display panel, a small chamber is formed by a multi-cell structure on a substrate, the small chamber is filled with a plastic dispersion liquid, and another substrate is pasted thereon. Manufacture electrophoretic display panel. In the second embodiment, a small chamber formed by a large number of recesses formed in a substrate is filled with a plastic dispersion liquid, and another substrate is attached to manufacture a panel for magnetophoretic display. Alternatively, a recess may be provided in one or both of the substrates, and the substrates may be combined to form an independent small chamber between the substrates. In the third embodiment, a microcapsule enclosing a plastic dispersion liquid is applied to a substrate and a binder is applied.
To produce a magnetophoretic display panel. In some cases, a protective layer may be provided on the surface of the microcapsule coating layer in order to prevent the microcapsules from being broken by friction pressure.

[0019]

Embodiments of the present invention will be described with reference to the drawings. Example 1 Hydrogenated castor oil (THIXCIN RH) was added to an isoparaffin solvent (Isopar-M: manufactured by Exxon Chemical Co., Ltd.).
EOX, Inc. ) Was added, and the mixture was dissolved by heating and then cooled to obtain a dispersion liquid. This dispersion liquid and titanium oxide (Trademark CR-50, manufactured by Ishihara Sangyo Co., Ltd.) are mixed with a wet disperser (T.
K. (Homomixer: manufactured by Tokushu Kika Kogyo Co., Ltd.) to obtain a white dispersion liquid. Then, while stirring with a propeller in a mixed solvent of acetone, methyl ethyl ketone, toluene, and an alcoholic mixed solvent (Solmix: manufactured by Nippon Alcohol Sales Co., Ltd.), a butyral resin (S-lek BL-) was used as a binder. 1: Sekisui Chemical Co., Ltd.)
Was dissolved to obtain a resin solution. While stirring the resin solution with a TK homomixer, daylight fluorescent pigment 2 (FA-43:
(Shinloich Co., Ltd.) and stirred, and further, stainless steel (DAP410L: manufactured by Daido Special Steel Co., Ltd.) as light-reflective magnetic particles 1 was granulated and colored by a spray-dry method or the like. Is dried, and
150 μm red magnetic particles were obtained. The red magnetic particles were mixed with the white dispersion liquid to obtain a plastic dispersion liquid. Honeycomb structure of approximately 0.08 mm thick vinyl chloride sheet, approximately 0.065 mm thick vinyl chloride, approximately 2 mm on each side, approximately hexagonal and approximately 0.8 mm high as a transparent substrate on the front side Was bonded using an ethylene-vinyl acetate adhesive to form a display panel portion. Next, the plastic dispersion liquid is filled in each of the small chambers having a multi-cell structure, and the structure on the back side is sealed with a transparent vinyl chloride sheet of about 0.15 mm using an epoxy-based adhesive, followed by magnetophoretic display. Panel was prepared.

Example 2 A resin solution obtained in the same manner as in Example 1 was mixed with a TK homomixer.
While stirring with titanium oxide (Trademark CR-50:
Ishihara Sangyo Co., Ltd.) and daylight fluorescent pigment (FA-4)
3: Shinloich Co., Ltd.) and stirred, and further, stainless steel (DAP410L:
The product obtained by adding Daido Steel Co., Ltd.) is granulated and colored by a spray-dry method or the like, dried, and dried.
Pink magnetic particles (not shown) of up to 150 μm were obtained. The pink magnetic particles were mixed with the white dispersion liquid to obtain a plastic dispersion liquid. As a transparent substrate on the front side, on a vinyl chloride sheet of about 0.15 mm, a substantially hexagonal shape of about 2 mm on one side made of vinyl chloride of about 0.065 mm and a height of about 0.8 mm
Was bonded using an ethylene-vinyl acetate adhesive to produce a display panel portion. Next, the plastic dispersion liquid is filled in each of the small chambers having a multi-cell structure, and a transparent vinyl chloride screen of about 0.08 mm is formed on the back side.
Then, sealing was performed using an epoxy-based adhesive to produce a panel for magnetophoretic display.

Example 3 To a resin solution obtained in the same manner as in Example 1, titanium oxide (Taipek CR-50, manufactured by Ishihara Sangyo Co., Ltd.) was added as a white hiding agent 3, and the mixture was stirred. Magnetic particles 11
Nickel steel (TYPE CHT: NOVAMET)
Co., Ltd.) was granulated by spray-drying and white concealed magnetic particles were obtained by white concealing the surface. afterwards,
The white opaque magnetic particles are colored by a spray-dry method with a daylight fluorescent pigment 12 (FA-48: manufactured by Shinloich Co., Ltd.) by a spray-dry method, and dried,
Produce 150 μm blue magnetic particles. The blue magnetic particles were mixed with a white dispersion liquid obtained in the same manner as in Example 1 to obtain a plastic dispersion liquid. As a transparent substrate on the back side, about 0.
A large number of continuous recesses of approximately 0.8 mm in depth were formed in a 15 mm vinyl chloride sheet using a vacuum forming die. Next, each of the recesses is filled with the plastic dispersion liquid, and a transparent substrate sheet of about 0.08 mm is used as a substrate on the front side and sealed using an epoxy-based adhesive. Was prepared.

Example 4 The daylight fluorescent pigment 22 (FA-43: manufactured by Shinloich Co., Ltd.) was colored on the white opaque magnetic particles obtained in the same manner as in Example 2 by a spray-dry method, and dried. 10
150 μm light-reflective magnetic particles 21 and daylight fluorescent pigment 22
Then, hollow red magnetic particles having a gap 4 are prepared. The red magnetic particles were mixed with a white dispersion liquid obtained in the same manner as in Example 1 to obtain a plastic dispersion liquid. As a transparent substrate on the front side, a vinyl chloride sheet of about 0.08 mm, a thickness of about 0.08 mm
A honeycomb-structured multi-cell board made of 65 mm of vinyl chloride and having a regular hexagonal shape with a side of about 2 mm and a height of about 0.8 mm is adhered using an ethylene-vinyl acetate adhesive to form a display panel. Produced. Next, the plastic dispersion liquid is filled in each of the small chambers of the multi-cell structure, and a transparent structure of about 0.1
The panel was sealed with a 5 mm vinyl chloride sheet using an epoxy-based adhesive to produce a magnetophoretic display panel.

Example 5 A thickener (Aerosil-200: manufactured by Nippon Aerosil Co., Ltd.) and carbon black (# 40: manufactured by Mitsubishi Chemical Corporation) were added to an isoparaffin solvent (Isopar M: manufactured by Exxon Chemical Co., Ltd.). Was added and mixed and dispersed with a wet disperser (TK homomixer: manufactured by Tokushu Kika Kogyo Co., Ltd.) to obtain a black dispersion liquid. Further, as a white hiding agent 33, calcium carbonate (MC-
T: made by Maruo Calcium) and titanium oxide (made by I-Trade CR-50: manufactured by Ishihara Sangyo Co., Ltd.) and stirred. Further, nickel steel (TYPE) was used as the light-reflective magnetic particles 31.
CHT (manufactured by NOVAMET Co.) was added thereto to obtain white concealed magnetic particles obtained by granulating by spray-drying and concealing the surface in white. Thereafter, the daylight fluorescent pigment 32 (FA-45J: Sinloich Co., Ltd.) was colored on the white concealed magnetic particles by a spray-dry method, and dried,
Porous yellow magnetic particles having small holes 5 in a 50 μm daylight fluorescent pigment 32 are prepared. The yellow magnetic particles were mixed with the black dispersion liquid to obtain a plastic dispersion liquid. The microcapsules enclosing the plastic dispersion liquid are applied to a substrate and bonded to the substrate by a binder. Further, in order to prevent the microcapsules from being broken by friction pressure, a protective layer is provided on the surface of the microcapsule application layer. Was provided to produce a magnetophoretic display panel.

In order to obtain colored magnetic particles having a hollow or porous shape, the drying speed may be increased. The method may be to raise the drying temperature or use a solvent having good drying properties. A general method for increasing the drying speed may be appropriately selected.

In the embodiment of the present invention, color magnetic particles are prepared by the spray-dry method. However, spherical or oval spherical iron powder having a particle diameter that reduces the coloring degree and hiding power of the particles themselves is used together with a dye as a binder. It is a matter of course that it can be produced by other methods such as a method of pulverizing after dispersing in a resin or the like from a known technique.

[0026]

Since the magnetophoretic display panel of the present invention has the above-described structure, characters and patterns displayed on the substrate by a magnetic pen or the like are colored by a difference in contrast between a writing portion and a non-writing portion. There is an advantage that a magnetophoretic display panel capable of displaying can be provided only by slightly increasing the manufacturing cost.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a color magnetic particle of Example 1 of the present invention.

FIG. 2 is a longitudinal sectional view of a color magnetic particle of Example 2 of the present invention.

FIG. 3 is a longitudinal sectional view of a color magnetic particle of Example 3 of the present invention.

FIG. 4 is a longitudinal sectional view of a color magnetic particle of Example 4 of the present invention.

[Explanation of symbols]

 1, 11, 21, 31 Light-reflective magnetic particles 2, 12, 22, 32 Daylight fluorescent pigment 3, 23, 33 White hiding agent 4 Gap 5 Small hole

Claims (5)

[Claims] 1. A magnetophoretic display panel in which magnetic particles, a dispersion medium, a plastic dispersion liquid comprising a thickener and, if desired, a colorant are arranged between two substrates, wherein the magnetic particles are formed of a light-reflective magnetic material. A panel for magnetophoretic display in which color magnetic particles, which are particles and are colored with a daylight fluorescent pigment or a daylight fluorescent dye, using a binder on the surface of the light-reflective magnetic particles. 2. The color magnetism according to claim 1, wherein a binder is used on the surface of the light-reflective magnetic particles, and the surface is colored with a white hiding agent and a daylight fluorescent pigment or a daylight fluorescent dye. Magnetophoretic display panel enclosing particles. 3. The light-reflective magnetic particle according to claim 1, wherein the surface of the light-reflective magnetic particles is coated with a white hiding agent and colored with a daylight fluorescent pigment or a daylight fluorescent dye. Magnetophoretic display panel enclosing color magnetic particles. 4. A color magnetic particle according to claim 1, wherein said light-reflective magnetic particles have a surface colored with a daylight fluorescent pigment or a daylight fluorescent dye. Panel for magnetophoretic display. 5. The color according to claim 1, wherein the surface of the light-reflective magnetic particles is colored with a daylight fluorescent pigment or a daylight fluorescent dye in a porous manner. Magnetophoretic display panel enclosing magnetic particles.