JP5224589B2 - Dichroic particles with improved display performance - Google Patents

Description

  The present invention relates to a dichroic particle and an image display device. More specifically, the present invention relates to a dichroic particle suitably used as a display element of a particle rotation type image display apparatus, and a particle rotation type image display apparatus having the particle as a display element.

  There are various methods for displaying images. For example, CRT (CRT), PDP (Plasma Display Panel), LCD (Liquid Crystal Display), FED (Electrolytic Emission Display).

  The CRT emits light by scanning an electron beam in which electrons are converged with a fluorescent material, and the PDP encloses a high-pressure noble gas in a region having a phosphor layer sandwiched between two electrodes. A voltage is applied to gas to generate ultraviolet rays to generate light, and the LCD changes the polarization state of light from the backlight through the liquid crystal and changes the display according to the orientation of the liquid crystal. Emits electrons by emitting electrons into a vacuum and making them collide with a phosphor.

  In addition to the display device as described above, there is a display method called particle rotation type display in which particles classified into two colors are arranged in an insulating resin and the two-color particles are rotated. In this display method, particles having regions of two or more colors are dispersed in a light transmissive support such as silicone rubber, and a voltage is applied by sandwiching the light transmissive support between electrodes. A specific color region of all particles is oriented in the same direction. This is possible because the charging characteristics of each color region of the particles are different. In addition, if the specific gravity of each color area of the particles is matched, the rotation performance of the particles will increase, and once the voltage is applied, the direction of the particles will be fixed in that direction, and even if the device that applies the voltage is turned off That state continues (this is called memory characteristics). Therefore, the particle rotation type display is a display method excellent in power saving. On the other hand, in this method, since it takes time for the particles to rotate, it is not suitable for a display device in which the displayed image changes rapidly, for example, a display device that displays a moving image. It is suitable for displaying still images such as figures, and is expected to be applied to so-called electronic paper.

  Various particles have been developed as particles used for the particle rotation type display. For example, Patent Document 1 (Japanese Patent Application Laid-Open No. 64-42683) discloses a particle composed of a wax-like substance as a main material and a pigment and a dye.

  In Patent Document 2 (Japanese Patent Laid-Open No. 11-352421), a white microball hemisphere formed of glass, titanium oxide, zinc oxide, zirconia, alumina or the like is colored by sputtering with TiC or the like. Particles obtained by doing so are disclosed.

Further, Patent Document 3 (JP 2000-122103 A) discloses a two-color ball obtained by coating a glass ball filled with titanium dioxide with a black material.
JP-A 64-42683 Japanese Patent Laid-Open No. 11-352421 JP 2000-122103 A

  However, the particles disclosed in these patent documents are mainly white / black dichroic particles, and in the other color combination particles, the cause is unknown, but the rotation of the particles when a voltage is applied. Performance (rotational speed) is insufficient.

  An object of the present invention is to provide a dichroic particle having excellent rotational performance of a particle when a voltage is applied, and particularly when a voltage is applied to particles having a color combination other than a white / black color combination. The purpose is to achieve high rotation performance.

  The inventor of the present invention has included a conductive white pigment in a hemispherical portion that constitutes one color (ground color) of the two-color particles, so that even in a combination of colors other than a combination of white / black, It has been found that high rotational performance can be achieved when a voltage is applied, and the present invention has been completed.

That is, the dichroic particles of the present invention are resin dichroic particles in which the individual spherical particles are approximately bisected into different colors in appearance, and the approximately hemisphere of the dichroic particles has a powder resistivity of 1 It comprises a conductive white pigment in the range of ˜100 Ωcm, constitutes a ground color, and the remaining substantially hemisphere of the dichroic particles is colored in any color other than the ground color It is a two-color particle.

  The conductive white pigment can be produced, for example, by treating the white pigment with a conductive material selected from the group consisting of antimony oxide / tin oxide and indium oxide / tin dioxide to impart conductivity.

The powder resistivity of the conductive white pigment blended in the substantially hemisphere constituting the ground color of the dichroic particles is usually in the range of 1 to 100 Ωcm.
As described above, the dichroic particles having a high dielectric constant of the ground color substantially hemisphere and having a difference in dielectric constant between hemispheres have high rotational performance when a voltage is applied.

  The substantially hemisphere colored in an arbitrary color excluding the ground color is colored with, for example, a chromatic dye or a chromatic color pigment. In this case, the substantially hemispherical portion colored in an arbitrary color other than the ground color Contains a chromatic dye or chromatic pigment.

The average particle diameter of the dichroic particles is usually in the range of 30 to 200 μm on a volume basis in consideration of particle rotation efficiency.
Further, the dichroic particle of the present invention is suitable as a display element of a particle rotation type image display device, and the particle rotation type image display device of the present invention is an insulating material that contains dichroic particles rotatably between a pair of electrodes. A particle rotation type image display device made of a resin, wherein the two-color particles are resin-made two-color particles in which individual spherical particles are roughly divided into two different colors in appearance, The hemisphere includes a conductive white pigment having a powder resistivity in the range of 1 to 100 Ωcm and constitutes a ground color, and the remaining substantially hemisphere of the dichroic particles is an arbitrary color excluding the ground color The dichroic particles are rotated in the insulating resin by a voltage applied between the electrodes.

In the particle rotation type image display device, it is preferable that the dichroic particles float in a rotatable manner in an insulating liquid impregnated in the insulating resin.
In the particle rotation type image display device, the voltage applied between the pair of electrodes is preferably in the range of 50 to 300V.

According to the present invention, dichroic particles having excellent rotational performance of particles when a voltage is applied, particularly dichroic particles having a combination of colors other than a combination of white / black having excellent rotational performance, and the two colors A particle rotation type image display device having particles as display elements is provided.

Hereinafter, the dichroic particle of the present invention and a particle rotation type image display apparatus having the dichroic particle as a display element will be described in detail.
[Dichroic particles of the present invention]
The dichroic particles of the present invention are resin dichroic particles in which the individual spherical particles are substantially bisected into different colors in appearance. The substantially hemisphere of the dichroic particles contains a conductive white pigment, and the white pigment mainly composed of the conductive white pigment constitutes the ground color. The remaining substantially hemisphere of the dichroic particles is colored in an arbitrary color except the ground color.

  That is, the dichroic particle of the present invention has a dielectric region in which approximately half of one particle contains a conductive white pigment, and the remaining substantially half that contains a colorant without containing a conductive component. Area (colored area).

  The dielectric region forming approximately half of one particle of the dichroic particle of the present invention contains a conductive white pigment whose powder resistivity is usually in the range of 1-100 Ωcm, preferably 1-30 Ωcm. Preferably, the dielectric region is formed of a resin and a crosslinked structure is formed in the dielectric region.

  In this dielectric region, the conductive white pigment is usually in an amount in the range of 1 to 10 parts by weight, preferably 2 to 5 parts by weight with respect to 100 parts by weight of the total weight of the conductive white pigment and the resin. It is contained in. By containing the conductive white pigment in such an amount, a region occupying about half of the two-color particles exhibits conductivity and a high dielectric constant.

  The potential difference between the dielectric region in the dichroic particle and the colored region containing the coloring material causes the dichroic particle of the present invention placed between a pair of electrodes to rotate according to the voltage applied to the electrode. It becomes a driving force.

  The dielectric region containing the conductive white pigment is generally white reflecting the color of the conductive white pigment, but may be colored within a range that does not impair the characteristics of the dielectric region. If colored yellow, the background color of the dichroic particles of the present invention is yellow. That is, in the dichroic particles of the present invention, the component that determines the characteristics of the dielectric region that occupies approximately half is a conductive white pigment, and since the conductive white pigment itself is white, The original ground color is white. For this reason, the ground color of the two-color particles can be adjusted to any color from white to light to dark to black. Such characteristics are the characteristics of the dichroic particles of the present invention that can be achieved by using a conductive white pigment in the dielectric region, and black conductive carbon black or the like is used as the conductive material. The ground color cannot be adjusted by stacking colors as described above.

  As described above, in the dichroic particles of the present invention, the dielectric region can be freely colored. Therefore, the colored regions constituting the remaining half of the dichroic particles are appropriately selected according to the color of the dielectric region. be able to. In general, the formed image becomes clearer by coloring with a color opposite to or similar to the color of the dielectric region.

The ratio of the resin and the colorant in the colored region may be such that the color of the dielectric region cannot be seen through the colored region, and the colorant may be used, and the total amount of resin and colorant is 100 parts by weight. ,
The colorant is usually used in an amount in the range of 1 to 70 parts by weight, preferably in the range of 2 to 50 parts by weight.

The colored region is made of a resin and a coloring material dispersed or dissolved in the resin. It is preferable that the colored region also has a crosslinked structure as in the dielectric region.
The dichroic particles of the present invention having such a structure can be produced by various methods. Usually, the dichroic particles of the present invention are roughly classified into three types. Specifically, it is roughly classified into a microchannel method (for example, see JP-A-2004-199083), a dropping method (for example, see JP-A-2004-199022) and a crushing method (for example, see JP-A-2004-294628). Is done. These methods will be described below.

[Microchannel method]
In this microchannel method, as shown in FIG. 1, a colored continuous phase 6 divided into two colors is transferred in a first microchannel 1 and continuously in a second microchannel 2 in which a fluid medium flows. It is discharged sequentially or intermittently. Since the colored continuous phase and the fluid medium have an insoluble relationship of O / W or W / O with each other, the discharged colored continuous phase flows in the second microchannel and is spherical due to the interfacial tension. Particle 12 ′ is obtained. The colored continuous phase contains a resin or its monomer, and the resin or its monomer is polymerized and cured by UV irradiation and / or heating when the colored continuous phase is discharged and spheroidized. Thus, resin-made two-color particles in which the individual spherical particles are substantially bisected into different colors in terms of appearance are completed.

<Colored continuous phase>
The colored continuous phase is divided into two colors, and both phases contain a resin or its monomer, a coloring material such as a dye or a pigment, and other optional components. The phase (ground hue) that forms a substantially hemisphere constituting the ground color in the dichroic particles of the present invention contains a coloring material and a conductive white pigment for imparting conductivity to the substantially hemisphere constituting the ground color, The phase (arbitrary colored phase other than the ground color) that is substantially hemispherically colored in an arbitrary color except the ground color contains an arbitrary coloring material other than the ground color. Arbitrary coloring phases other than the said ground hue and ground color are obtained by mixing these containing components.

(Resin or its monomer)
Examples of the resin include acrylic resins, styrene resins, ethylene resins, vinyl chloride resins, vinyl acetate resins, and the monomers include those capable of forming the resin.

As a specific example of the monomer,
The main monomers used in the present invention include (meth) acrylic monomers, styrene monomers and vinyl monomers.

  Examples of the (meth) acrylic monomers include: (meth) acrylic acid alkyl esters such as methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, octyl (meth) acrylate, (meth) acrylic Cycloalkyl (meth) acrylates such as cyclohexyl acid, esters of (meth) acrylic acid and bicyclic alcohols such as isobornyl acrylate, (meth) acrylic such as phenyl (meth) acrylate and benzyl (meth) acrylate And acid aryl esters.

  Examples of the styrenic monomer include: styrene, methyl styrene, dimethyl styrene, trimethyl styrene, ethyl styrene, diethyl styrene, triethyl styrene, propyl styrene, butyl styrene, hexyl styrene, heptyl styrene and octyl styrene, fluorostyrene, chlorostyrene, Examples thereof include bromostyrene, dibromostyrene, chloromethylstyrene, nitrostyrene, acetylstyrene, methoxystyrene, α-methylstyrene, vinyltoluene, and sodium p-styrenesulfonate.

  Examples of the vinyl monomers include: vinyl acetate, vinyl propionate, vinyl n-butyrate, vinyl isobutyrate, vinyl pivalate, vinyl caproate, vinyl persate, vinyl laurate, vinyl stearate, vinyl benzoate, Examples thereof include vinyl pt-butyl benzoate and vinyl salicylate.

  Examples of other monomers used in the present invention include: vinylidene chloride, vinyl chlorohexanecarboxylate, β-methacryloyloxyethyl hydrogen phthalate, perfluoroethylene, perfluoropropylene, vinylidene fluoride, vinyltrimethoxysilane, vinyl A triethoxysilane is mentioned.

In order to improve the dispersibility of the coloring material in the monomer or to adjust the dielectric constant of each hemisphere constituting the dichroic particles, at least one functional group;
A monomer having an amide group, amino group, hydroxyl group, epoxy group, or nitrile group in the molecule may be used in combination.

  Examples of monomers having a carboxyl group in the molecule are unsaturated carboxylic acids; acrylic acid, methacrylic acid, tetrahydrophthalic acid, itaconic acid, citraconic acid, crotonic acid, maleic acid, fumaric acid, isocrotonic acid, norbornene And dicarboxylic acid, bicyclo [2,2,1] hept-2-ene-5,6-dicarboxylic acid and the like, and maleic anhydride, itaconic anhydride, citraconic anhydride, tetrahydrophthalic anhydride as derivatives thereof. Examples include acid, bicyclo [2,2,1] hept-2-ene-5,6-dicarboxylic anhydride, and acid halide.

Examples of monomers having an amide group in the molecule are amide group-containing vinyl monomers; acrylamide, methacrylamide, and N-methylol methacrylamide, N-methoxyethyl methacrylamide, N-butoxymethyl methacrylamide, Acrylamide derivatives such as N, N-dimethylacrylamide, N, N-dimethylaminopropylacrylamide, N-methylacrylamide, and (meth) acrylamides such as N-methylol (meth) acrylamide and diacetone acrylamide, 6-amino Examples include hexyl succinimide and 2-aminoethyl succinimide.

  Examples of monomers having an amino group in the molecule are amino group-containing vinyl monomers; aminoethyl (meth) acrylate, propylaminoethyl (meth) acrylate, dimethylaminoethyl methacrylate, (meth) acrylic Alkylpropyl derivatives of acrylic acid or methacrylic acid such as aminopropyl acid, phenylaminoethyl methacrylate, cyclohexylaminoethyl methacrylate, vinylamine derivatives such as N-vinyldiethylamine, N-acetylvinylamine, allylamine, methacrylamine, N -Allylamine derivatives such as methylacrylamine, and aminostyrenes such as p-aminostyrene.

  Examples of monomers having a hydroxyl group in the molecule: (meth) acrylic acid-2-hydroxyethyl, (meth) acrylic acid-2-hydroxypropyl, monoester of (meth) acrylic acid and polypropylene glycol or polyethylene glycol , And adducts of lactones and 2-hydroxyethyl (meth) acrylate.

Examples of monomers having an epoxy group in the molecule include: glycidyl (meth) acrylate, mono and diglycidyl esters of maleic acid, mono and diglycidyl esters of fumaric acid, mono and diglycidyl esters of crotonic acid, tetrahydrophthalic acid Mono and diglycidyl esters of dicarboxylic acids such as mono and diglycidyl esters of itaconic acid, mono and diglycidyl esters of butenetricarboxylic acid, mono and diglycidyl esters of citraconic acid, mono and glycidyl esters of allyl succinic acid Examples thereof include alkyl glycidyl esters of esters and p-styrene carboxylic acid.

Examples of the monomer having a nitrile group in the molecule include acrylonitrile and methacrylonitrile.
In this invention, such a monomer can be used individually by 1 type or in combination of 2 or more types.

  The resin is obtained by polymerizing the corresponding monomer. For example, when the above-mentioned colored continuous phase is discharged and spheroidized, the monomer or resin is cured while becoming spherical due to its interfacial tension by UV irradiation and / or heating, and has a spherical shape It becomes a cured product.

(Conductive white pigment)
The conductive white pigment is obtained, for example, by treating a white pigment with a conductive material of either antimony oxide / tin oxide or indium oxide / tin dioxide to impart conductivity, thereby forming a ground color. Used to impart conductivity to a substantially hemisphere. Examples of the white pigment include titanium oxide and zinc oxide.

  Here, the treatment is specifically an operation of coating or impregnating with the above-mentioned conductive material using a spherical white pigment (for example, titanium oxide) as a core. When the white pigment is titanium oxide, the titanium oxide may be a rutile type or an anatase type. The coating or impregnation can be performed by mixing a white pigment with a conductive material in a wet or dry manner. The conductive white pigment thus obtained is also commercially available. For example, a conductive white pigment commercially available under the trade name ET-500W (manufactured by Ishihara Sangyo Co., Ltd.) can be used.

  In the present invention, the amount of the white pigment and the covering material (or impregnating material) constituting the conductive white pigment can be appropriately set, but the weight ratio of the white pigment and the covering material (or impregnating material) (white) The pigment: coating material (or impregnating material) is usually set in the range of 95: 5 to 70:30, preferably 90:10 to 80:20. By using a covering material or an impregnating material within the above range, good conductivity can be imparted to the white pigment.

Further, the particle diameter of the conductive white pigment is usually 0.10 to 5 μm, preferably 0.10 to 0.5 μm.
The powder resistivity of the conductive white pigment is usually 1 to 100 Ωcm, preferably 1 to 30 Ωcm.

  In the present invention, the above-described conductive white pigment and a white pigment not subjected to conductive treatment can be mixed and used.

(Coloring material)
Examples of the colorant include achromatic dyes, achromatic pigments, chromatic dyes, and chromatic pigments.

Specifically, black ... Olesolol Fast Black, BONJET BLACK CW-1, Solvent Black 27Cr (trivalent) 5% containing, Pigment Black7,
Water, red ... VALIFAST RED 3306, Olesolol Fast RED BL, Solvent RED 8Cr (trivalent) 5.8% contained, Permanent Carmain FBB02-JP
Blue ... Kaya Set Blue, Solvent Blue 35, Cyanine Blue Yellow ... VALIFAST YELLOW 4120, Oil Yellow 129, Solvent Yellow 16, Solvent Yello
w 33, Disperse Yellow 54, PV Fast Yellow H2G
Lemon ... Piast Yellow 8005
Green ... Oil Green 502, Opias Green 502, Solvent Green 3,
Magenta: VALIFAST PINK 2310N, Plast RED D-54, Plast RED 8355, Plast RED 8360, Plast Vioiet 8850, Disperse Violet 28, Solvent RED 149, Solvent RED 49, Solvent RED 52, Solvent RED 218Cr (trivalent) 4 Containing,
Cyan ・ ・ ・ VALIFAST BLUE 2610, VALIFAST BLUE 2606, Oil BLUE 650, Plast BLUE 8580, Plast BLUE 8540, Oil BLUE 5511, Solvent Blue 70 Cu4% contained,
Orange ... Oil Orange 201, VALIFAST ORANGE 3210, Solvent Orange 70, Kayaset Orange G,
Brown ・ ・ ・ VALIFAST BROWN 2402, Solvent Yellow 116, Kayaset Flavine FG, etc.

Also, for example, solvent blue, solvent red, solvent orange, solvent green, lumogen F orange, etc. can be mentioned.
In addition, for example, dyes and heat-sensitive dyes commonly used in writing recording liquids such as clarine, perylene, dicyanopinyl, azo, quinophthalone, aminopyrazole, methine, dicyanoimidazole, indoaniline, phthalocyanine Leuco dyes used as recording paper or temperature sensitive coloring materials, rhodamine B stearate (red 215), tetrachlorotetrabromofluorescene (red 218), tetrabromofluorescene (red 223), sudan III (red 225), dibromofluorescein (orange 201), diiodo fluorescein (orange 206), fluorescein (yellow 201), quinoline yellow SS (yellow 204)
, Quinizarin green SS (green 202), azurin purple SS (purple 201), medicinal scarlet (red 501), oil red XO (red 505), orange SS (orange 403), yellow AB (yellow 404) No.), Yellow OB (Yellow No. 405), Sudan Blue B (Blue No. 403) and other tar dyes used in cosmetics can also be mentioned as the colorant.

  These dyes can be used alone or in admixture of two or more. Further, various direct dyes, acid dyes, basic dyes, azoic dyes, reactive dyes, fluorescent dyes and fluorescent dyes can be used as necessary. It is possible to disperse in a brightener, and further in the above (meth) acrylic monomer.

Further, for example, as a yellow pigment, permanent yellow DHG, Lionol Yellow 1212B, Shimla First Yellow 4400, Pigment Yellow 12,
Pigment Red 57: 1 as magenta pigment, Lionol Red 6B-4290G, Irgarite Rubin 4BL, Fastgen Super Magenta RH,
As a cyan pigment, Lionol Blue 7027, Fastgen Blue BB, Chromophthal Blue 4GNP,
Carbon black, black pearls 430, Bengala, ultramarine blue,
As the white pigment, various inorganic / organic pigments such as titanium white, zinc sulfide, zinc oxide, alumina white, and calcium carbonate having no conductivity can be used.

  In the present invention, it is included in the phase (ground hue) that constitutes a substantially hemisphere constituting the ground color and the phase (arbitrary colored phase other than the ground color) that is colored in any color other than the ground color, The total amount of the colorant is usually 0.1 to 50 parts by weight, preferably 2 to 40 parts by weight with respect to 100 parts by weight of the total amount of the resin and its monomers in each phase. Moreover, when represented by a volume fraction, it is preferably 1 to 20%.

(Polymerization initiator)
In the present invention, it is preferable to include a polymerization initiator in the ground color phase and any colored phase other than the ground color.

  Specifically, the polymerization initiator is used so that the monomer that is polymerized to become a resin easily initiates the polymerization reaction, and in the present invention, the polymerization initiator is preferably contained in the colored continuous phase.

  Examples of the polymerization initiator include persulfates such as potassium persulfate and ammonium persulfate, peroxides such as benzoyl peroxide and laurium peroxide, and azo compounds such as asobisisobutyronitrile. Examples of polymerization initiators preferably used during coloring and polymerization include, for example, 2,2′-azobis (2-methylpropionitrile), 2,2′-azobis (2-methyl) as azo polymerization initiators. Butyronitrile), 2,2′-azobis (2,4-dimethylvaleronitrile), 2,2′-azobis (2-dichloropropylpropionitrile), 1,1′-azobis (cyclohexane-1-carbonitrile) ), Dimethyl-2,2'-azobis (2-methylpropionate).

These polymerization initiators are generally used in an amount of 0.01 to 5 parts by weight, preferably 0.5 to 2 parts by weight, per 100 parts by weight of the monomer.
As other polymerization initiators, for example, conventionally known acetophenones as photopolymerization initiators; for example, acetophenone, 2,2-diethoxyacetophenone, p-dimethylaminoacetophenone, methoxyacetophenone, 2,2-dimethoxy-2- Phenylacetophenone, 2-hydroxy-2-cyclohexylacetophenone,
Ketones; for example, benzophenone, 2-chlorobenzophenone, p, p′-dichlorobenzophenone, p, p′-bisdiethylaminobenzophenone, N, N′-tetramethyl-4,4′-diaminobenzophenone (Michler ketone), 4 -(2-hydroxyethoxy) phenyl (2-hydroxy-2-propyl) ketone,
Moreover, benzoin ethers; for example, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzyl methyl ketal, benzoyl benzoate, α-acyloxime ester, and thioxanthone can be mentioned.

  Examples of the thermal decomposition type polymerization initiator include peroxyesters, organic peroxides, organic hydroperoxides, organic peroxyketals, and azo compounds.

Examples of peroxyesters include: tert-hexylperoxypivalate, tert-butylperoxyneodecanate, tert-butylperoxybenzoate, tert-hexylperoxy-2-ethylhexanoate, hexylperoxyneo Examples include decanate, cumylperoxyneodecanate, and 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate.

  Examples of organic peroxides include: dicumyl peroxide, di-tert-butyl peroxide, tert-butyl cumyl peroxide, dilauroyl peroxide, dibenzoyl peroxide, diacetyl peroxide, didecanoyl peroxide, di- Examples thereof include isononyl peroxide and 2-methylpentanoyl peroxide.

  Examples of organic hydroperoxides include: tert-butyl hydroperoxide, cumyl hydroperoxide, 2,5-dimethyl-2,5-dihydroperoxyhexane, p-methane hydroperoxide, diisopropylbenzene A hydroperoxide is mentioned.

  Organic peroxyketals include, for example, 1,1-bis (tert-hexylperoxy) -3,3,5-trimethylcyclohexane, 1,1-bis (tert-hexylperoxy) cyclohexane, 1 , 1-bis (tert-butylperoxy) 3,3,5-trimethylcyclohexane.

Examples of azo compounds include: 2,2′-azobisisobutyronitrile, 2,2′-azobis-2,4-dimethylvaleronitrile, 2,2′-azobiscyclohexylnitrile, 1,1 ′ -Azobis (cyclohexane-1-carbonitrile), 2-phenylazo-4-methoxy-2,4-dimethylvaleronitrile, dimethyl-2,2'-azobisisobutyrate.

  These polymerization initiators can be used alone or in combination of two or more.

(Multifunctional monomer)
In the present invention, a polyfunctional monomer having two or more functionalities may be blended in the background hue and any colored phase other than the background color and reacted with the main monomer or other monomer used in the present invention described above. Good.

  Examples of the bifunctional or higher polyfunctional monomer include (poly) alkylene glycol diacrylates, triacrylates, tetraacrylates, or (poly) alkylene glycol dimethacrylates. And trimethacrylic acid esters and tetramethacrylic acid esters.

  Examples of these are ethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, neopentyl glycol di (Meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, 1,1,1-trishydroxymethylethane diacrylate, 1,1,1-trishydroxymethylethane triacrylate, 1, 1,1-trishydroxymethylpropane triacrylate, N-methylol acrylate, 1,9-nonanediol diacrylate, 2-butyl-2-ethyl-1,3-pro Mention may be made of the emissions diacrylate.

  The bifunctional or higher polyfunctional monomer is used for introducing a crosslinked structure into the resin. The cross-linking structure is not essential, but the dichroic particles have a cross-linking structure, so that the insulating liquid such as silicone oil and the dichroic particles of the present invention are in contact with each other in the particle rotation type image display device of the present invention described later. Even so, the dichroic particles of the present invention are not swollen by the insulating liquid, and the dichroic particles can be stably suspended in the insulating liquid in the insulating resin.

  Moreover, such a polyfunctional monomer is normally used in an amount of 10 to 90 parts by weight in 100 parts by weight of the monomer to be the resin described above. In addition, a polyfunctional monomer can be polymerized using only it and a crosslinked structure can be formed, and the polymer of a polyfunctional monomer can also be used as the resin in the dichroic particle of the present invention.

(Other optional ingredients)
Other optional components contained in the colored continuous phase (that is, any color phase other than the ground color and the ground color) include UV sensitizers, charge control agents, pigment dispersants, heat stabilizers, conductive agents, antiseptics. Agents, surface tension modifiers, antifoaming agents, rust inhibitors, antioxidants, near infrared absorbers, ultraviolet absorbers, fluorescent agents, fluorescent whitening agents, and the like.

  The UV sensitizer is used to exert the effect of the photopolymerization initiator more strongly, and examples thereof include n-butylamine, triethylamine, tri-n-butylphosphine and the like.

  The charge control agent is added to the ground hue and / or an arbitrary colored phase other than the ground color, thereby adjusting the charging characteristics of each substantially hemisphere of the obtained dichroic particles and applying a voltage. Used to improve the rotational performance of dichroic particles. Examples of charge control agents include styrene acrylic polymers, calixarene derivatives, hindered amines, azine compounds, salicylic acid metal complexes, phenol condensates, lecithin, pararosarinin, nigrosine dyes, alkoxylated amines, alkylamides. , Phosphorus and tungsten simple substances and compounds, molybdate chelate pigments, fluorine-based activator, hydrophobic silica, metal salt of monoazo dye, sulfonylamine of copper phthalocyanine, oil black, metal salt of naphthenate, benzyltributylammonium-4-hydroxy And quaternary ammonium salts such as naphthalene-1-sulfonate. The charge control agent may also serve as a colorant, or the colorant may serve as a charge control agent.

  The charge control agent is usually used in an amount of 0.05 to 5 parts by weight, preferably 0.5 to 2 parts by weight with respect to 100 parts by weight of the monomer to be the resin.

<Fluid medium>
As described above, the fluid medium used in the microchannel method has a relationship of O / W or W / O with the colored continuous phase. In other words, the colored continuous phase is not dissolved in the fluid medium, and the colored continuous phase is colored continuously. Since the phase becomes spherical, the colored continuous phase can be freely deformed in this fluid medium.

  Examples of the fluid medium include a polyvinyl alcohol aqueous solution, a carboxymethyl cellulose aqueous solution, and a hydroxymethyl cellulose aqueous solution in which polyvinyl alcohol is dissolved in ion exchange water. Since the colored continuous phase is often an oily phase (O phase), the fluid medium is preferably an aqueous phase (W phase).

<Method for producing dichroic particles>
In the microchannel method, which is an example of the method for forming dichroic particles of the present invention, as shown in FIG. 1, a colored continuous phase 6 divided into two colors is transferred in the first microchannel 1 to flow. The liquid is continuously or intermittently discharged into the second microchannel 2 in which the conductive medium flows. Since the colored continuous phase and the flowable medium exist in an insoluble state in which they form an O / W or W / O state with each other, the discharged colored continuous phase passes through the second microchannel. While flowing, spherical particles 12 'are formed by the interfacial tension. This colored continuous phase contains a resin or its monomer, and the resin or its monomer is polymerized and cured by UV irradiation and / or heating when the colored continuous phase is discharged and spheroidized. As a result, a cured resin body is usually formed, and two-color particles are produced in which the individual spherical particles are substantially bisected into different colors in appearance.

  In this method, when the channel width of the microchannel is very small, such as several hundred μm, the fluid (colored continuous phase) flowing therethrough is dominated by viscosity, so the number of lay nozzles is approximately 1000 or less and the laminar flow state Tend to be. The same is true even if the colored continuous phase is split into two colors, and the colored continuous phase split into two colors tends to be transferred in a nearly laminar flow state. It can be easily transferred in the microchannel.

The speed at which the colored continuous phase is transferred in the first microchannel depends on the viscosity, surface tension, density, liquidity (polar group), etc. of the colored continuous phase, but normal flow F1 = 0.01 to 10 m.
The flow rate is 1 / hr, preferably 0.01 to 5 ml / hr, and can be appropriately transferred or discharged into the second microchannel.

  Further, the flow F2 ml / hr of the fluid medium flowing in the second microchannel is not particularly limited as long as the discharged colored continuous phase is spheroidized while flowing, but normal flow F2 = 1 to 100 ml / hr. The flow rate is preferably 1 to 50 ml / hr.

  The flow ratio represented by F2 / F1 is the liquidity such as the production amount of the dichroic particles to be produced, the average particle size and particle monodispersity, the fluid viscosity, density and surface tension of the colored continuous phase and the fluid medium. Can be set as appropriate.

  The colored continuous phase discharged into the second microchannel is formed into spherical particles during discharge, dispersion, and transfer while being separated into two colors, and the resin or the monomer in the discharged colored continuous phase is subjected to UV irradiation and / or Polymerized and cured by heating. Since the spherical shape of the discharged colored continuous phase after spheroidization is stable, this polymerization curing does not necessarily occur even if the colored continuous phase does not completely polymerize and cure while flowing in the second microchannel. The treatment can be appropriately performed under UV irradiation and / or heating in a separate container which is a collecting tank for dichroic particles provided outside the microchannel system.

The irradiation amount when irradiating UV is usually 300 to 1500 mJ / cm ² , the heating temperature when heating is usually 60 to 100 ° C., and the heating time is 20 to 120 minutes.
In addition, in order to transfer the colored continuous phase 6 of two hues [6a / 6b] into the first microchannel 1, the liquid inflow end of the first microchannel is transferred to the liquid inlet end of the first microchannel, for example, by the method illustrated in FIG. Hue [6a / 6b] is supplied. As shown in FIG. 2A, the third microchannel 3 and the fourth microchannel 4 are joined to the liquid inflow end of the first microchannel 1 so as to form a V shape. From the third and fourth microchannels, ground colors and arbitrary colored phases other than the ground colors 6a and 6b are supplied to the first microchannel 1, and two hues [6a / 6b] are supplied into the first microchannel 1. The colored continuous phase 6 is formed. In the system shown in FIG. 2A, the third microchannel 3 and the fourth microchannel 4 that form a V shape are preferably provided on the same plane as the first microchannel 1. In addition, the intersection angle θ5 = 90 ± 80 ° forming the V-shape at the joint portion, preferably the intersection angle θ5 = 90 ± 60 °.

  In addition, a colored continuous phase that is divided into two colors by the method illustrated in FIG. 2B can be supplied to the first microchannel. In the method illustrated in FIG. 2B, for example, an intersection angle (or opening angle) θ6 is in an acute angle range in the transfer direction of the hue 6b in the middle portion of the first microchannel 1 to which the hue 6b is transferred. In this way, the third microchannel 8 is joined, and the hue 6a is supplied from the third microchannel 8, thereby forming the colored continuous phase 6 of two hues [6a / 6b] in the first microchannel 1. Can do.

  Furthermore, the dichroic particles of the present invention can also be produced in the manner shown in FIG. The liquid outflow end port of the first microchannel 1 and the liquid inflow end port of the cylindrical second microchannel 2 in which the fluid medium 7 flows at a predetermined flow F expressed in units of ml / hr are coaxial with each other. It is joined to.

  On both sides on the same surface in the vicinity of the connecting portion, both side microchannels 5a and 5b in the direction of transport of the colored continuous phase 6 in the first microchannel are respectively intersecting angles θ3 and θ4 = 45 ± 5-40. It is joined to the second microchannel 2 in the range of °.

As apparent from FIG. 3, the colored continuous phase 6 of the two-color phase [6a / 6b] transferred to the first microchannel 1 is the front end port of the first microchannel 1 (or the connecting portion) ( At the liquid outflow end), the fluidized medium 7 supplied from both side microchannels 5a and 5b is discharged into the second microchannel 2 so as to be scraped off, and a spheroidized product 12 'of the colored continuous phase 6 is formed. The

  The crossing angles θ3 and θ4 formed by both side microchannels and the first microchannel are preferably θ3 = θ4, and the crossing angles θ3 and θ4 are in a range of 45 ± 5 to 40 ° in FIG. 3 as described above. Is an acute angle. Although not shown in the figure, the intersection angles θ3 and θ4 can be implemented as a right angle or an obtuse angle of 90 ° or more.

  Examples of the shapes of the vertical cut openings of the first microchannel to the third microchannel and the side microchannel described above include a circle, an ellipse, and a quadrangle (square, rectangle, trapezoid). From the viewpoint of microfabrication when the microchannel having such a shape is formed of a material such as a glass plate or a plastic plate, for example, the shape of the vertical cut opening of the microchannel is preferably a square (square, rectangle). . And when these microchannel cutting openings are rectangular (or rectangular), the long sides of the cutting openings are in the range of 0.5 to 500 μm, and the short sides of the cutting openings are in the range of 0.5 to 500 μm. Is preferred. More preferably, each lower limit is 1 μm.

[Droplet method]
In the droplet method, a first droplet having a ground color and a second droplet having an arbitrary hue other than the ground color are brought into contact with each other in air or in a liquid to form a single droplet. The dichroic particles of the present invention are produced by contact and solidification instantaneously.

  As the coloring material for coloring the first droplet and the second droplet, the same coloring material as that used in the microchannel method can be used. Further, in the droplet method, in addition to the components used in the microchannel method, an amine compound such as 1,6 hexanediamine, sodium alginate, sodium carboxymethylcellulose, and polyvinyl alcohol are added to the first droplet and the second liquid. They can be used as constituents of droplets, which react with the reaction solution. The first droplet contains a conductive white pigment. Furthermore, a charge control agent or a charge control agent may be blended as an optional component of the first droplet and the second droplet.

<Method of forming droplets in air or liquid>
First, a method for forming droplets in air will be described. The first and second liquid droplets can be formed by ejecting liquids (first liquid and second liquid) composed of the respective components, for example, with a spray nozzle or an ink jet nozzle.

  Next, a method for forming droplets in the liquid will be described. The first and second droplets can be formed by discharging into a liquid in which the first liquid and the second liquid are not dissolved. For example, when the first and second liquids are hydrophilic liquids, they may be discharged into a non-hydrophilic solvent such as oil.

<Reaction solution>
Examples of the reaction liquid include acid chlorides such as sebacoyl chloride, isocyanates such as TDI, polyvalent cations such as calcium chloride, and acids such as borax and hydrochloric acid. These are appropriately selected depending on the components of the formed first and second droplets.

<Method for producing dichroic particles>
As described above, for example, the first and second droplets created by ejecting with an inkjet nozzle come into contact with each other in the air to form one droplet, and the reaction liquid is prepared at the place where the droplet falls. If this is done, the liquid droplets will be cured immediately upon contact with the reaction solution. In this way, the dichroic particles of the present invention are produced.

[Crushing method]
In the crushing method, a laminate (C) comprising a layer composed of the thermoplastic resin ground color composition (A) and a thermoplastic resin colored composition (B) colored in an arbitrary color other than the ground color is laminated on the laminated surface. The dichroic hitting in a substantially vertical direction is crushed to obtain crushed pieces, and the crushed pieces are heated to produce the dichroic particles of the present invention. In the crushing method, the crushed pieces need to be deformed into a spherical shape by heating. Therefore, the resin that constitutes the dichroic particles needs to be a thermoplastic resin.

As the thermoplastic resin used in the thermoplastic resin ground color composition (A) and the thermoplastic resin coloring composition (B), a known thermoplastic natural resin or synthetic resin can be used.
Specifically, for example, natural resins such as rosin, pentaerythritol ester of rosin, and dammar; acrylic resins obtained by (co) polymerizing acrylic monomers that can be used in the microchannel method, styrene- Synthetic resins such as (meth) acrylic acid ester copolymers, styrene- (meth) acrylic acid copolymers, polystyrene, maleic acid resins, polyvinyl chloride, polyesters, thermoplastic polyurethanes can be used.

  The above resins can be used alone or in admixture of two or more. However, in the crushing method, after the laminate made of the thermoplastic resin is produced, it is crushed into small pieces and then granulated by heating, so that it has flexibility suitable for crushing force and has a glass transition temperature of 60 ° C. The above resins are preferred.

<Method for Producing Laminate (C)>
As a method for preparing the laminate (C), for example, a paint (A1) containing a thermoplastic resin ground color composition (A) is applied on a substrate and dried, and then a thermoplastic resin coloring composition is used. The coating (B1) containing (B) is laminated and dried, then the coating method is peeled off from the substrate, the coating (A1) is sprayed on the substrate and dried, and then the coating (B1) is sprayed. , A method of peeling from a substrate after drying, or a method of spreading a plate-like material or an ingot on which a thermoplastic resin ground color composition (A) and a thermoplastic resin coloring composition (B) are stacked with a heating roller or the like. Can be mentioned.

  In these methods, a solvent is required, and examples of the solvent include alcohols, esters, ketones, glycol ethers, glycol esters, and glycol ether esters.

<Method for producing dichroic particles>
In the crushing method, the laminated body (C) is crushed by a point-like blow in a direction substantially perpendicular to the laminated surface to obtain a crushed piece, and the crushed piece is heated.

  The point-like impact has a shape capable of giving an impact to a point-like narrow area, for example, a needle-like shape or a cone-like shape, and gives an impact larger than the breaking strength of the laminate (C). It is given by a striker made of a material that can be used, such as steel or stainless steel.

Specifically, the substantially vertical direction is ± 15 ° in the vertical direction.
With the above-mentioned striking element, the laminated body (C) is crushed by giving a point-like blow in a direction substantially perpendicular to the laminated surface, and the obtained crushed pieces are heated. More specifically, among the thermoplastic resins contained in the thermoplastic resin ground color composition (A) or the thermoplastic resin coloring composition (B), the crushed pieces are heated with hot air or the like. Heat to the melting start temperature of the resin or higher to melt. The crushed pieces are spheroidized into a spherical shape by the interfacial tension of the thermoplastic resin, and dichroic crushed pieces are cooled to obtain two-color particles.

[Dichroic particles of the present invention]
For example, the dichroic particles of the present invention produced by the above-mentioned method are made of a resin, and in appearance, the individual spherical particles are approximately bisected into different colors. In addition, a ground color is formed, and the remaining substantially hemisphere of the dichroic particles is colored in an arbitrary color other than the ground color.

  As described above, the dichroic particles of the present invention have a large difference between the dielectric constant of the substantially hemisphere of the ground color and the dielectric constant of the substantially hemisphere colored in any color other than the ground color. to differ greatly. Therefore, the dichroic particles of the present invention are excellent in the rotational performance of the particles when a voltage is applied, and are particularly high even in particles having a color combination other than the combination of white / black colors, which has been insufficient in conventional rotational performance. Rotational performance is achieved.

  The average particle diameter of the dichroic particles of the present invention is usually in the range of 30 to 200 μm, preferably 70 to 150 μm, expressed on a volume basis. Dichroic particles having an average particle diameter in this range are likely to rotate when a voltage is applied. In addition, the variation in the particle diameter is usually 20% or less, preferably 5% or less, and more preferably 3% or less, when the uniformity is expressed as a Cv value.

The average particle diameter can be adjusted as follows.
When the microchannel method is employed, the average particle diameter of the obtained dichroic particles becomes small due to the limitation of the discharge amount, the limitation of the nozzle, the limitation of the resin viscosity, and the like.

  When the droplet method is employed, for example, when the first and second droplets are produced by spraying with a spray nozzle or the like, the particle diameter of both droplets is reduced by reducing the nozzle hole diameter. Therefore, as a result, the particle diameter of the dichroic particles is also reduced. In the droplet method, sodium alginate or the like that reacts with the reaction solution is used as a solution dissolved in a solvent. Therefore, the first and second droplets also contain a solvent. When dichroic particles are prepared and dried, the solvent evaporates and the particle size becomes smaller than before the solvent evaporates. Therefore, the average particle diameter of the dichroic particles can be adjusted by adjusting the concentration of components other than the solvent of the first and second droplets.

  When the crushing method is adopted, the size of the obtained two-color particles can be controlled by adjusting the density of the needles by making the striker that gives a dot-like hitting into a bundle-like bundle of needles. . That is, after obtaining dichroic particles by changing the needle density, the density of the needles that can efficiently obtain the desired particle diameter can be determined by measuring the particle diameter. The relationship between the particle diameter and the needle density is affected by the size of the fragments that can be cracked by the striker.

[Particle rotation type image display device]
As described above, since the dichroic particles of the present invention are excellent in rotation performance when a voltage is applied, they are suitable as display elements for particle rotation type image display devices.

  A particle rotation type image display device comprising the dichroic particles of the present invention as a display element is a particle rotation type image display device made of an insulating resin that rotatably contains a dichroic particle between a pair of electrodes. The colored particles are resin-made dichroic particles in which the individual spherical particles are approximately bisected into different colors in appearance, and the substantially hemisphere of the dichroic particles includes a conductive white pigment, constituting a ground color. The remaining substantially hemisphere of the dichroic particles is colored in an arbitrary color except the ground color, and the dichroic particles are rotated in the insulating resin by a voltage applied between the electrodes. It is configured.

The particle rotation type image display device of the present invention generally has a sheet shape and can be manufactured through the following steps.
(1) A step of preparing a thermosetting resin composition in which the dichroic particles of the present invention are dispersed.
(2) A step of producing an insulating transparent resin sheet in which the two-color particles are dispersed by applying the thermosetting resin composition to a substrate and then thermosetting the composition.
(3) A display member in which the insulating transparent resin sheet is dipped in an insulating liquid to swell the sheet and form a vacuole of the insulating liquid so as to wrap the dichroic particles dispersed inside. Manufacturing step.
(4) A step of laminating electrode members on both surfaces of the display member.

  The thermosetting resin used in the thermosetting resin composition in the step (1) is not particularly limited as long as both insulation and transparency are excellent, but has flexibility when used as a display sheet. A two-component curable silicone resin can be suitably used. Hereinafter, a particle rotation type image display apparatus using a two-component curable silicone resin as a thermosetting resin will be described.

  A thermosetting resin composition mix | blends the two-color particle | grains of this invention with a two-pack curable silicone resin so that the content rate may be 40-60 volume%, and mixes with a stirrer. If the content of the dichroic particles is less than 40% by volume, the resulting display sheet may not be sufficiently concealed, and the display characteristics of the image display device may be deteriorated. On the other hand, if it exceeds 60% by volume, the amount of the resin is insufficient, and it may be difficult to uniformly apply the thermosetting resin composition to the base material during sheet preparation.

  The said thermosetting resin composition can be apply | coated to a base material by a well-known and usual means. The viscosity of the thermosetting resin composition is usually as high as 5000 to 10000 mPa · s, and suitable coating means include, for example, those of single wafer coaters such as wire bar coating, applicator coating, and spin coating. Other examples include continuous coaters such as knife coaters, comma coaters, die coaters, and lip coaters.

  The substrate used at this time is not particularly limited as long as it can be used without any problem at the temperature at which the thermosetting resin as a subsequent step is cured, but polyethylene terephthalate (PET) having excellent strength and dimensional stability. ) Is preferred.

  The coating thickness of the thermosetting resin composition is preferably 2 to 4 times the average particle diameter expressed on the volume basis of the dichroic particles of the present invention. If it is smaller than 2 times, coarse particles or the like are caused during coating on the substrate, and coating unevenness is likely to occur, and the concealability of the resulting display sheet may be insufficient. On the other hand, when the ratio is larger than four times, the dichroic particles are arranged in multiple layers in the thickness direction, whereby the reflectance of the display sheet is lowered and the display quality may be deteriorated.

  The coating film of the thermosetting resin composition is heated and cured. Curing is preferably performed at a temperature as high as possible within a range not exceeding the glass transition temperature of the thermoplastic resin used for the dichroic particles.

  An insulating transparent resin sheet in which the two-color particles of the present invention are dispersed is obtained by peeling the thermosetting coating film of the thermosetting resin composition from the substrate. Since the dichroic particles dispersed in the insulating transparent resin sheet are in close contact with the cured matrix resin, they do not rotate even when an electric field is applied. Therefore, by immersing the insulating transparent resin sheet in an insulating liquid and swelling the cured product of the thermosetting resin composition, a vacuole filled with the insulating liquid around the dichroic particles is formed. Can be formed.

The insulating liquid used can swell the cured thermosetting resin, and does not dissolve or swell any of the resin used in the dielectric region and the colored region of the dichroic particle of the present invention. There must be. Examples of such insulating liquids include silicone oil, higher fatty acid esters, polyolefin ethers, isoparaffins, and fluorinated polyethers.

  When the thermosetting resin is the silicone resin, silicone oil can be suitably used as the insulating liquid. Since the silicone oil has a high affinity with the silicone resin, it swells the cured silicone resin, but does not dissolve or swell any of the resins used for the dielectric region and the colored region.

  As the silicone oil, for example, methylphenyl polysiloxane, dimethyl polysiloxane, or the like can be used. The viscosity of the silicone oil at 25 ° C. is preferably 100 mPa, s or less. When the viscosity exceeds 100 mPa, s, it becomes difficult to rotate the two-color particles in the vacuole, and the display response speed may be reduced. Increasing the electric field strength to compensate for this tends to cause problems such as increased power consumption for image rewriting and the like. The specific gravity of the silicone oil is preferably selected to be close to the specific gravity of the dichroic particles.

  The conditions for immersing the insulating transparent resin sheet in which the dichroic particles are dispersed in the insulating liquid vary depending on the type of the thermosetting resin and the insulating liquid to be used and the degree of curing of the thermosetting resin. When the thermosetting resin is a two-component curable silicone resin and the insulating liquid is a silicone oil, a vacuole is usually formed at room temperature in 10 to 24 hours. This time can be shortened by setting the temperature at which the insulating transparent resin sheet is immersed in the insulating liquid as high as possible within a range not exceeding the glass transition temperature of the resin used for the dichroic particles.

  Next, the particle rotation type image display device of the present invention is obtained by laminating electrode layers on both sides of the sheet-like display member obtained by the above method. For that purpose, a sheet-like electrode member provided with an electrode layer on one side of the substrate, for example, a plastic film provided with an electrode layer on one side, may be laminated on both sides of the sheet-like display member as a substrate. At this time, the electrode surface of the substrate and the surface of the sheet-shaped display member do not necessarily need to be in close contact, and the surface opposite to the electrode surface of the substrate may be in close contact with the sheet-shaped display member. Further, a single-layer or multilayer plastic film having gas barrier properties may be interposed between the sheet-like display member and the substrate for the purpose of preventing leakage of the insulating liquid and blocking outside air.

  As the base material on which the electrode layer is laminated, plastic films and sheets such as vinylidene chloride, vinyl chloride, polyethylene, polypropylene, and polyethylene terephthalate, glass plates, and the like can be used. For the electrode layer, a metal foil having a low electric resistance value such as aluminum, copper, nickel, a thin film formed by vapor deposition or sputtering, or a transparent electrode such as indium tin oxide (ITO), antimony tin oxide (ATO) tin oxide A foil film or the like can be used.

  In the particle rotation type image display device of the present invention obtained by laminating such an electrode layer on both surfaces of the sheet-like display member, at least the viewing-side electrode layer of the device, the substrate on which the electrode layer is laminated, and the necessity All plastic films used according to the requirements must be transparent. This is because the image displayed by the apparatus cannot be seen unless it is transparent.

  When laminating the substrates on both sides of the sheet-like display member, an adhesive or a double-sided pressure-sensitive adhesive sheet may be used. Also in this case, it is necessary to select a material so as not to impair the transparency on the viewing side of the display sheet.

The particle rotation type image display device of the present invention obtained by the above method is applied by applying a voltage usually in the range of 50 to 500 V, preferably in the range of 50 to 300 V, between the electrodes of the substrate. The two-color particles floating in the insulating liquid in the cured body of the thermosetting resin composition can be rotated.

  In the particle rotation type image display device of the present invention, the thermosetting resin (excellent in insulation and transparency) contains the dichroic particles of the present invention in a freely rotatable manner, so that a voltage is applied. Since the dichroic particles have excellent rotational performance, quick display is possible.

  Also, if the specific gravity of the ground color approximately hemisphere of the two-color particle and the specific hemisphere colored in any color except the background color (hereinafter referred to as optional colored approximate hemisphere) are substantially the same (when the specific gravity is combined), the two-color particle The center of gravity becomes or approaches the center of the sphere, and the two-color particles are easily rotated. Furthermore, even after the voltage is applied to rotate the dichroic particles, the dichroic particles are rotated according to gravity and the display of the display device is not changed, and the memory characteristics are exhibited. Even if the specific gravity is somewhat different, the random rotation of the dichroic particles is suppressed by the binding force due to the viscosity of the insulating liquid such as silicone oil with respect to the dichroic particles, and the particle rotation type image display device of the present invention is Usually has memory characteristics.

When the specific gravity is adjusted as described above, the specific gravity of the ground color substantially hemisphere and the arbitrarily colored substantially hemisphere can be adjusted as follows, for example.
The ground color substantially hemisphere of the present invention contains a conductive white pigment. Therefore, the specific gravity of the ground color substantially hemisphere portion tends to be heavier than that of the arbitrarily colored substantially hemisphere.

  Therefore, the specific gravity of the ground color approximately hemisphere is reduced by reducing the content of the conductive white pigment contained in the ground color approximately hemisphere or increasing the content of other light components with a low specific gravity contained in the ground color approximately hemisphere. can do.

  On the other hand, in the arbitrarily colored substantially hemisphere, by increasing the content of the colorant having a high specific gravity or by adding a specific gravity adjuster having a heavy specific gravity without affecting the color of the arbitrarily colored substantially hemisphere, Specific gravity can be increased. Examples of the specific gravity adjusting agent include magnetite when the arbitrarily colored substantially hemisphere is black.

  By combining the specific gravity of the ground color substantially hemisphere and the arbitrarily colored substantially hemisphere in this way, dichroic particles that have excellent rotational performance when a voltage is applied and can serve as a display element of a particle rotation type image display device having memory characteristics are obtained. can get.

  As described above, the particle rotation type image display device of the present invention is excellent in rotation performance even if the dichroic particle as the display element is a dichroic particle having a color combination other than the combination of white / black, Since it has memory characteristics by predetermined adjustment, it can be expected to be applied to electronic paper.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited thereto.
[Preparation of Reactive Solution A-1]
As monomers for forming the resin, 20 parts by weight of methyl methacrylate (MMA) and 80 parts by weight of trimethylolpropane triacrylate (TMPTA) and titanium white (manufactured by Ishihara Sangyo Co., Ltd .; CR-50-2) 30 as a coloring material Part by weight and 5 parts by weight of conductive titanium (Ishihara Sangyo Co., Ltd .; ET-500W) are dispersed using a ball mill, and a quaternary ammonium salt (benzyltributylammonium-4-hydroxynaphthalene-1-) is used as a charge control agent. Sulfonate) 0.5 parts by weight was dissolved, and 5 parts by weight of hexyl peroxyneodecanate was dissolved as a thermal polymerization initiator to obtain a colored continuous phase reactive solution A-1.

The conductive titanium ET-500W is a rutile-type spherical titanium oxide coated with tin dioxide and antimony pentoxide as a core. In the conductive white pigment, the weight of titanium dioxide is 83%, The weight of tin dioxide is 10%, the weight of antimony pentoxide is 4%, the particle diameter of the conductive white pigment is 0.2 to 0.3 μm, and the powder resistivity at a pressure of 9,8 MPa is 2 to 5 Ωcm. The powder resistivity is obtained by pressure-molding a conductive white pigment powder at 9.8 MPa to prepare a sample piece, and measuring the resistance value between the upper and lower sides of the sample piece in the pressurized state. The thickness was measured, and the volume low efficiency was calculated from the measured resistance value and the thickness and cross-sectional area of the test piece.

[Preparation of Reactive Solution A-2]
As a monomer for forming the resin, 20 parts by weight of MMA and 80 parts by weight of TMPTA, 6 parts by weight of cyanine blue (manufactured by Dainichi Seika Kogyo Co., Ltd.) as a coloring material are dispersed using a ball mill, 1 part by weight of a metal complex (Orient Chemical Industries, Ltd .: BONTRON E-84) is dissolved, 5 parts by weight of hexylperoxyneodecanate is dissolved as a thermal polymerization initiator, and a colored continuous phase reactive solution A- 2 was obtained.

[Example 1]
Next, 1 part by weight of 88% saponified polyvinyl alcohol was dissolved in 100 parts by weight of ion-exchanged water, and this was used as an aqueous fluid medium B.

  The solutions A-1 and A-2 are merged using a microchannel device (θ5 = 90 °) shown in FIG. 2A, and this is combined with the microchannel device (θ3 = 45 °, θ4 = 45 shown in FIG. 3). From the first microchannel in the middle of the microchannel where the three flow paths of the side microchannels 5a and 5b and the first microchannel intersect, then the solution A-1 And A-2 at a total of 1 ml / hr, and the side microchannels on both sides thereof are discharged into a flowable medium B flowing at 20 ml / hr, and then flowing into a PTFE tube having a tube inner diameter of 1 mm, Polymerization hardening was performed through the inside.

By the above operation, white / blue dichroic particles having a uniform particle diameter were obtained. The average particle diameter on the volume basis was 100 μm, and the CV value was 2%.
The display performance of the obtained dichroic particles was confirmed as follows.

  After the above two-color particles 6 g are sufficiently dispersed in a two-component curable silicone resin and applied on a PET substrate so that the length is 200 mm × width 200 mm × height 0.3 mm after curing is complete, 80 ° C. Curing was completed for 10 hours to obtain a particle-containing resin sheet.

  Next, the obtained resin sheet is peeled off from the PET substrate and immersed in silicone oil (viscosity: 2 mPa, s) for 15 hours, so that the dichroic particles are wrapped in the silicone oil and can be freely rotated in the silicone resin. A new vacuole was obtained.

An electronic paper was prepared by sandwiching the silicone resin containing the vacuole with a glass plate coated with an ITO electrode on the surface via a multilayer plastic.
<Evaluation of particle rotation performance>
A voltage was applied to the electronic paper so that a potential difference of 100 V was generated between the electrodes, and the directions of the two-color particles were unified. The dichroic particles were inverted by reversing the method of applying a voltage between the electrodes. The state of reversal of the two-color particles at this time was confirmed, and the number of reversed particles (out of 200 particles) was counted. Table 1 below shows the results obtained by inverting 150 to 200 pieces as ○, and those obtained by inverting 0 to 150 pieces as x. Confirmation size is within 1mm square. Evaluation was made with an average value at N = 5.

<Evaluation of particle response performance>
A voltage was applied to the electronic paper so that a potential difference of 100 V was generated between the electrodes, and the directions of the two-color particles were unified. The dichroic particles were inverted by reversing the method of applying a voltage between the electrodes. At that time, the time until rotating particles could not be confirmed was measured. The confirmation size was set within about 1 mm square, and evaluation was performed with an average value at N = 5.

<Evaluation of color difference>
A voltage was applied to the electronic paper so as to generate a potential difference of 100 V between the electrodes, and the application method of the voltage between the electrodes was reversed between positive and negative, thereby inverting the two-color particles. The color difference was measured when the two-color particles were aligned in a single direction. For the measurement, TC-8600A (Tokyo Denshoku) was used. The results are shown in Table 1 below.

[Examples 2-6, Comparative Examples 1-2]
Dichroic particles and electronic paper were prepared in the same manner as in Example 1 except that the compositions of the colored continuous phase reactive solutions A-1 and A-2 were changed as shown in Table 1. Evaluation of particle rotation performance and particle response performance and color difference were performed. The results are shown in Table 1. The particle response performance was evaluated only for Example 1 and Comparative Example 1. As a result, the time required for the two-color particles of Example 1 to reverse was one third of the time required for the two-color particles of Comparative Example 1 to reverse. That is, the reversal speed of the dichroic particles of Example 1 was three times the reversal speed of the dichroic particles of Comparative Example 1.

  In Table 1 below, “parts” represents parts by weight.

Contents of abbreviations and the like in Table 1 are shown below.
IBXA: Isobornyl acrylate EGDMA: Ethylene glycol dimethacrylate CR-50-2: Titanium white manufactured by Ishihara Sangyo Co., Ltd.
PV Fast Yellow H2G: Yellow coloring material R-980 manufactured by Clariant Japan Co., Ltd. Titanium white ET-500W manufactured by Ishihara Sangyo Co., Ltd. Conductive white pigment conductive manufactured by Ishihara Sangyo Co., Ltd. Zinc oxide: Cyanine blue manufactured by Hakusuitec Co., Ltd .: Dainichi Seika Kogyo Co., Ltd .: 4920
Permanent Carmain FBB02-JP ... Red colorant manufactured by Clariant Japan Co., Ltd. 1,9-ND-A ... 1,9 Nonanediol diacrylate BMA ... Butyl methacrylate NPA ... Neopentyl glycol diacrylate BEPGA ... 2butyl-2 Ethyl-1,3-propanediol diacrylate CR-58: Titanium white KA-20 manufactured by Ishihara Sangyo Co., Ltd. Titanium white manufactured by Titanium Industry Co., Ltd.

FIG. 1 is a conceptual diagram showing a first microchannel for transferring a colored continuous phase and a second microchannel for manufacturing a dichroic particle in a method for manufacturing a dichroic particle described in Japanese Patent Application Laid-Open No. 2004-197083. It is a figure showing formation of a color particle. FIG. 2 is a conceptual diagram showing an example of a method for forming a colored continuous phase in the method for producing dichroic particles described in JP-A-2004-197083. FIG. 3 is a diagram showing one system of a method for producing dichroic particles described in Japanese Patent Application Laid-Open No. 2004-197083.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 1st microchannel 2 2nd microchannel 3 3rd microchannel 4 4th microchannel 5a, 5b Side microchannel 6 Colored continuous phase 7 Flowable medium 8 3rd microchannel 10 Colored continuous phase discharge 11 'Spherical shape Discharged material 12 'dichromated particles

Claims (7)

In appearance, each spherical particle is a resin dichroic particle that is roughly bisected into different colors,
The substantially hemisphere of the dichroic particles includes a conductive white pigment having a powder resistivity in the range of 1 to 100 Ωcm , and constitutes a ground color.
A dichroic particle characterized in that the remaining substantially hemisphere of the dichroic particle is colored in an arbitrary color except the ground color.   The conductive white pigment contained in the substantially hemisphere constituting the ground color of the dichroic particles is treated by treating the white pigment with a conductive material selected from the group consisting of antimony oxide / tin oxide and indium oxide / tin dioxide. The dichroic particle according to claim 1, wherein the dichroic particle is imparted with a property.   The dichroic particle according to claim 1, wherein the substantially hemisphere colored in an arbitrary color excluding the ground color contains a chromatic dye or a chromatic pigment.   2. The dichroic particle according to claim 1, wherein an average particle diameter of the dichroic particle is in a range of 30 to 200 [mu] m on a volume basis. A particle rotation type image display device made of an insulating resin containing dichroic particles rotatably between a pair of electrodes,
The dichroic particles are resin-made dichroic particles in which individual spherical particles are roughly divided into two different colors in appearance,
The substantially hemisphere of the dichroic particles includes a conductive white pigment having a powder resistivity in the range of 1 to 100 Ωcm , and constitutes a ground color.
The remaining substantially hemisphere of the dichroic particles is colored in any color except the ground color,
A particle rotating image display device, wherein the two-color particles are rotated in the insulating resin by a voltage applied between the electrodes. 6. The particle rotating image display device according to claim 5 , wherein the dichroic particles are rotatably suspended in an insulating liquid impregnated in the insulating resin. 6. The particle rotation type image display device according to claim 5 , wherein a voltage applied between the pair of electrodes is in a range of 50 to 300V.

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