JP2014066913A - Non-electrostatic resin particle, and application of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide non-electrostatic resin particles capable of suppressing precipitation of electrostatic colored resin particles and non-electrostatic resin particles, when having been dispersed in a dispersion medium together with the electrostatic colored resin particles.SOLUTION: Non-electrostatic resin particles are non-electrostatic resin particles formed by polymerizing a vinyl-based monomer indicating a measured value of a charge amount of 5 nC/cmor less, when placed between a pair of ITO electrodes forming parallel flat plates with a distance between electrodes of 50 μm and with an applied voltage of 15 V during 60 s, in a state of being dispersed in a silicone oil having dynamic viscosity of 100 cSt or less and with solid concentration of 30 wt.%. When viscosities at 25°C and at a shear rate of a non-electrostatic resin particle dispersed body which is dispersed in a nonpolar solvent with solid concentration of 30 wt.% of 10 sand 1000 sare set to be ηand η, respectively, 1.2≤η/η≤10 is satisfied.

Description

  The present invention relates to non-chargeable resin particles capable of suppressing sedimentation of chargeable colored resin particles and non-chargeable resin particles when dispersed in a dispersion medium together with the chargeable colored resin particles, and uses thereof. More specifically, the present invention relates to non-chargeable resin particles, a non-chargeable resin particle dispersion using the same, and an electrophoretic display device.

  2. Description of the Related Art In recent years, image display devices (electrophoretic display devices) using colored particles as image display elements using electrophoresis of charged colored particles such as colored resin particles (charged colored resin particles) exhibiting charging properties have been developed. Attention has been paid. This electrophoretic display device is inexpensive, has a viewing angle as wide as a normal printed matter, has low memory consumption, and has a memory property that displayed information does not disappear even when the power is turned off. Because of its advantages, it is expected to be widely used as an inexpensive display device.

  An electrophoretic display device typically includes two electrode substrates that are disposed opposite to each other with a spacer interposed therebetween, and at least one of which is transparent, and a display liquid as an image display element enclosed between these electrode substrates. A display panel including the display panel, wherein the display liquid is a dispersion liquid in which positively charged charged colored particles and / or negatively charged charged colored particles are dispersed in a dispersion medium. The electrophoretic display device having the above configuration can display an image by causing electrophoretic migration of charged colored particles by applying an electric field between the two electrode substrates of the display panel (see Patent Documents 1 to 4).

  In addition, as an electrophoretic display device, a dispersion system in which at least one type of electrophoretic particles (colored particles) having different optical characteristics (color tone) from the dispersion medium is dispersed in a colored dispersion medium is used as a display liquid. An electrophoretic display device is known in which the dispersion system is enclosed in a number of microcapsules and these microcapsules are arranged between the electrode substrates (see Patent Document 2).

  However, in the electrophoretic display device of Patent Document 2, when colored particles are arranged on a transparent electrode substrate serving as a display surface by applying a voltage, a dispersion medium having a color tone different from that of the colored particles is placed in the gap between the colored particles. As a result, color mixing occurs and the desired display is not achieved.

  As a technique for solving the problem of Patent Document 2, for example, charged colored particles (A) that move in a dispersion medium in response to an electric field, and colored particles (B) that do not move in a dispersion medium in response to an electric field (B) ) Is used in a dispersion medium (see Patent Document 3). In this electrophoretic display device, a base color corresponding to paper is displayed by colored particles (B), and an image color corresponding to characters and / or pictures drawn on paper is displayed as charged colored particles (A). By displaying on the screen, it is possible to display an image corresponding to paper on which characters and / or pictures are drawn. In Patent Document 3, it is said that display with high contrast can be realized by the electrophoretic display device. Patent Document 3 describes that, as the colored particles (B), it is possible to use hollow particles made of an organic polymer that are colored by dyeing.

JP 2006-293028 A Japanese Patent No. 2551783 JP 2001-188269 A JP 2006-220969 A

  However, these colored particles have a low image memory property when used as an electrophoretic display device because the colored particles gradually settle with time in the dispersion medium due to the difference in specific gravity with the dispersion medium. There was a problem.

  As a technique for improving the memory property of an image, Patent Document 4 discloses a suspension of a suspension by using a particle group including colored charged electrophoretic particles having thixotropic properties and transparent particles, and a dispersion medium. An electrophoretic display device has been described in which the display image memory performance of a plane transfer type electrophoretic element due to increased viscosity in a low shear region is improved. Further, in Patent Document 4, the viscosity of the suspension in the low shear rate region is made larger than the viscosity of the suspension in the high shear region, thereby increasing the viscosity of the suspension and increasing the viscosity of the suspension. Techniques for preventing movement are described.

  However, since the colored particles used in the technique described in Patent Document 4 are charged electrophoretic particles, it is impossible to use the colored particles as non-chargeable resin particles. Further, the transparent particles used in the technique described in Patent Document 4 are given thixotropy due to the attractive force between particles derived from hydrogen bonds, dipole-dipole interactions, Van der Waals forces, etc. in the dispersion medium. Therefore, the charging property may be imparted, and as a result, the transparent particles themselves may migrate when a voltage is applied. Therefore, the electrophoretic display device described in Patent Document 3 is required. As non-chargeable resin particles, it could not be used.

  An object of the present invention is to provide a non-chargeable resin particle capable of suppressing sedimentation of the chargeable colored resin particle and the non-chargeable resin particle when dispersed in a dispersion medium together with the chargeable colored resin particle, and a non-charge using the same It is providing a conductive resin particle dispersion and an electrophoretic display device.

In order to solve the above-mentioned problems, the non-chargeable resin particles of the present invention are separated from each other in a state where the kinematic viscosity is dispersed in a silicone oil having a solid content concentration of 30% by weight in 100 cSt (centistokes) or less. Charge amount measurement of 5 nC / cm ² or less when a voltage of 15 V is applied for 60 seconds between a pair of parallel indium tin oxide (hereinafter abbreviated as “ITO”) electrodes having a thickness of 50 μm Non-chargeable resin particles obtained by polymerizing a vinyl-type monomer, wherein the non-chargeable resin particles are dispersed in a non-polar solvent at a solid content concentration of 30% by weight When the viscosity at 25 ° C. at shear rates of 10 s ⁻¹ and _{1000 s} ⁻¹ of the dispersion is η ₁₀ and η ₁₀₀₀ , respectively,
1.2 ≦ η ₁₀ / η ₁₀₀₀ ≦ 10
It is characterized by satisfying.

Here, the shear rate when mixing in a fluid, such as migration of chargeable colored resin particles (for example, chargeable colored resin particles) in a dispersion medium, generally exceeds 10 s ⁻¹ and is 1000 s ^−1. Shear is said to be in the following high shear rate region, and shear when particles (such as the non-chargeable resin particles of the present invention and the chargeable colored resin particles) settle slowly in the dispersion medium without migration. The speed is generally in a low shear rate range lower than the above range. In the present invention, the viscosity η ₁₀₀₀ at 25 ° C. at a shear rate of _{1000 s} ⁻¹ in the high shear rate region where migration of the charged colored resin particles occurs in the dispersion medium, and a shear rate of 10 s ⁻¹ lower than the high shear rate region. The ratio to the viscosity η ₁₀ at 25 ° C. is defined.

According to the above configuration, the viscosity η ₁₀ of the non-chargeable resin particle dispersion at 25 ° C. at a shear rate of 10 s ⁻¹ in the low shear rate region is 25 ° C. at a shear rate of 1000 s ⁻¹ in the high shear rate region. It is 1.2 times to 10 times the viscosity η ₁₀₀₀ of the non-chargeable resin particle dispersion of the above, and moderate pseudoplasticity (the viscosity is high when the shear rate is low, and the viscosity is low when the shear rate is high) Characteristic). Therefore, when the non-chargeable resin particles having the above-described configuration are dispersed in a dispersion medium together with the chargeable colored resin particles having a charging polarity and used in an electrophoretic display device, migration (driving) of the chargeable colored resin particles is performed. Since the viscosity of the non-chargeable resin particle dispersion liquid can be made moderately higher than that during migration of the chargeable colored resin particles (high shear rate region) in the state after completion of the process (low shear rate region). In addition, sedimentation of the charged colored resin particles and the non-charged resin particles can be suppressed.

Further, according to the above configuration, the non-chargeable resin particles having the above configuration have a charge amount measurement value of 5 nC / cm ² or less measured under the above-described conditions, and the chargeability is reduced. Therefore, when the non-chargeable resin particles having the above configuration are combined with the chargeable colored resin particles and used in the electrophoretic display device, the non-chargeable resin particles and the chargeable colored resin particles are aggregated, and the chargeable colored resin particles. The occurrence of color mixing due to migration of non-chargeable resin particles in the same direction as the migration direction can be suppressed.

  By these actions, the non-chargeable resin particles having the above-described configuration are dispersed in a dispersion medium together with the chargeable colored resin particles having a charging polarity and used in an electrophoretic display device. Since the sedimentation of the chargeable resin particles can be suppressed, it is possible to improve the memory property of the image and realize a good display.

In the present application documents, the “non-chargeable resin particles” are mutual particles having a mutual distance of 50 μm in a state of being dispersed in a silicone oil having a kinematic viscosity of 100 cSt or less at a solid content concentration of 30% by weight. It shall be a resin particle that shows a measured charge amount of 5 nC / cm ² or less when a voltage of 15 V is applied for 60 seconds between a pair of parallel flat ITO electrodes.

  The non-chargeable resin particle dispersion of the present invention is characterized by comprising a nonpolar solvent and the non-chargeable resin particles of the present invention dispersed in the nonpolar solvent.

  Since the non-chargeable resin particle dispersion having the above-described configuration is obtained by dispersing the non-chargeable resin particles of the present invention in a non-polar solvent, it was used in an electrophoretic display device in combination with the chargeable colored resin particles. Sometimes, the sedimentation of the chargeable colored resin particles and the non-chargeable resin particles can be suppressed, so that the memory property of the image can be improved and a good display can be realized.

  The electrophoretic display device of the present invention includes the non-chargeable resin particle dispersion of the present invention, and the non-charged resin particle dispersion is different in color tone from the non-chargeable resin particles dispersed in the non-polar solvent. It further comprises chargeable colored resin particles having the following characteristics.

  Since the electrophoretic display device having the above-described configuration is obtained by dispersing the chargeable colored resin particles in the non-chargeable resin particle dispersion of the present invention, the settling of the chargeable colored resin particles and the non-chargeable resin particles is suppressed. Therefore, it is possible to improve the memory property of the image and realize a good display.

  ADVANTAGE OF THE INVENTION According to this invention, when it disperse | distributes in a dispersion medium with a charging colored resin particle, the non-charging resin particle which can suppress sedimentation of a charging colored resin particle and a non-charging resin particle, and a non-charging using the same Resin particle dispersion and electrophoretic display device can be provided.

It is the schematic which shows the jig | tool used to measure the charge amount of the non-chargeable resin particle which concerns on one Example of this invention, the upper figure is a side view, and the lower figure is a top view.

[Non-chargeable resin particles]
The non-chargeable resin particles of the present invention comprise a pair of parallel flat ITO plates having a distance of 50 μm and dispersed in a silicone oil having a kinematic viscosity of 100 cSt or less at a solid concentration of 30% by weight. Non-chargeable resin particles obtained by polymerizing a vinyl monomer, showing a charge amount measurement value of 5 nC / cm ² or less when a voltage of 15 V is applied for 60 seconds while being sandwiched between electrodes, The viscosity at 25 ° C. at shear rates of 10 s ⁻¹ and 1000 s ⁻¹ of non-chargeable resin particle dispersions in which non-chargeable resin particles are dispersed in a non-polar solvent at a solid content concentration of 30% by weight is η ₁₀ and η, respectively. ₁₀₀₀
1.2 ≦ η ₁₀ / η ₁₀₀₀ ≦ 10
It is a non-chargeable resin particle satisfying the above.

[1. Vinyl monomer)
As the vinyl monomer, a monofunctional vinyl monomer can be used. The monofunctional vinyl monomer may be a monofunctional vinyl monomer having no polar group or may be a monofunctional vinyl monomer having a polar group. . In the present application document, the “polar group” is at least one selected from the group consisting of a cyano group, an amino group, an ammonium group, a hydroxyl group, a nitro group, a thiol group, a sulfonyl group, a phosphonyl group, a halogen group, and a glycidyl group. Refers to a species substituent. Therefore, the monofunctional vinyl monomer having no polar group is a monofunctional vinyl monomer that does not contain any of the substituents constituting the group. Here, “monofunctional” means having one ethylenically unsaturated group.

  In the non-chargeable resin particles of the present invention, the vinyl monomer is a dispersion stabilizer that is a macromonomer having one or more ethylenically unsaturated groups, and another vinyl monomer that is different from the dispersion stabilizer. It is preferable to include a monomer. That is, the non-chargeable resin particles are preferably those obtained by copolymerizing the dispersion stabilizer and the other vinyl monomer. Thereby, the dispersion stability of the non-chargeable resin particles in the non-polar solvent can be improved.

[1-1. (Dispersion stabilizer)
As the dispersion stabilizer, a macromonomer having one or more ethylenically unsaturated groups and having at least one hydrocarbon skeleton selected from the group consisting of a polybutadiene skeleton, a polyisoprene skeleton, and a polyisobutylene skeleton ( Hereinafter, it is preferable to use at least “a macromonomer having a hydrocarbon skeleton”. Examples of the macromonomer having a hydrocarbon skeleton include various compounds having an ethylenically unsaturated group at a terminal and at least one hydrocarbon skeleton selected from the group consisting of a polybutadiene skeleton, a polyisoprene skeleton, and a polyisobutylene skeleton. Can be used. The polybutadiene skeleton and the polyisoprene skeleton may be partially hydrogenated (hydrogenated) or not hydrogenated (not hydrogenated). ).

  The number average molecular weight of the macromonomer having a hydrocarbon skeleton is preferably in the range of 500 to 100,000, and more preferably in the range of 1000 to 50,000.

  As the macromonomer having the hydrocarbon skeleton, for example, terminal allylated polyisobutylene marketed under the trade name “EP600A” (number average molecular weight 20000, manufactured by Kaneka Corporation), terminal marketed under the trade name “EP400A”. Macros having a polyisobutylene skeleton such as allylated polyisobutylene (number average molecular weight 10,000, manufactured by Kaneka Corporation) and terminal allylated polyisobutylene (number average molecular weight 5000, manufactured by Kaneka Corporation) marketed under the trade name “EP200A”. Monomer: Terminally acrylated hydrogenated polybutadiene marketed under the trade name “SPBDA-S” (number average molecular weight 6000, manufactured by Osaka Organic Chemical Co., Ltd.), single-end methacrylic marketed under the trade name “L-1253” Hydrogenated polybutadiene (Clayton Polymer Japan Co., Ltd.) Macromonomer having a hydrogenated polybutadiene skeleton such as a terminal product, and a terminally acrylated unhydrogenated polybutadiene (manufactured by Osaka Organic Chemical Industry Co., Ltd.) sold under the trade name “BAC-45”; a trade name “UC-102” And a macromonomer having a hydrogenated polyisoprene skeleton such as terminal acrylated hydrogenated polyisoprene (manufactured by Kuraray Co., Ltd.). 1 type may be used for the macromonomer which has the said hydrocarbon frame | skeleton, and 2 or more types may be used together. The macromonomer having a hydrocarbon skeleton is preferably a macromonomer having a hydrocarbon skeleton having no polar group. Thereby, the chargeability of the non-chargeable resin particles can be further reduced.

When the non-chargeable resin particles are formed by copolymerization of the dispersion stabilizer and the other vinyl monomer, the macromonomer having the hydrocarbon skeleton is used as a dispersion stabilizer, so At least one hydrocarbon molecular chain selected from the group consisting of a polybutadiene molecular chain, a polyisoprene molecular chain, and a polyisobutylene molecular chain can be introduced to the surface of the resin particle, and the non-charged resin particle is placed in a nonpolar solvent. When the dispersion is made into a non-chargeable resin particle dispersion, the pseudoplasticity of the non-chargeable resin particles is improved, and the desired viscosity characteristics (viscosity ratio η ₁₀ / η ₁₀₀₀ 1.2 ≦ η ₁₀ / η ₁₀₀₀ ≦ 10)).

The amount of the macromonomer having a hydrocarbon skeleton is preferably in the range of 0.1 to 15 parts by weight, and 0.1 to 10 parts by weight with respect to 100 parts by weight of the other vinyl monomer. More preferably within the range of parts. When the amount of the macromonomer having the hydrocarbon skeleton is less than 0.1 parts by weight with respect to 100 parts by weight of the other vinyl monomer, the hydrocarbon molecule introduced into the surface of the non-chargeable resin particles Since there are fewer chains, when the non-charged resin particles are dispersed in a non-polar solvent to form a non-chargeable resin particle dispersion, the desired viscosity characteristics (viscosity ratio η ₁₀ / Η ₁₀₀₀ may not be imparted with a characteristic satisfying 1.2 ≦ η ₁₀ / η ₁₀₀₀ ≦ 10). On the other hand, when the amount of the macromonomer having the hydrocarbon skeleton exceeds 15 parts by weight with respect to 100 parts by weight of the other vinyl monomer, the hydrocarbon molecular chain becomes excessive on the surface of the non-chargeable resin particles. Therefore, when non-chargeable resin particles are dispersed in a nonpolar solvent to form a non-chargeable resin particle dispersion, the non-chargeable resin particles may aggregate.

  Moreover, it is preferable to use together the macromonomer which has the said hydrocarbon skeleton, and the silicone macromonomer which has an ethylenically unsaturated group as said dispersion stabilizer. By using the macromonomer having the hydrocarbon skeleton and the silicone macromonomer together as a dispersion stabilizer, a non-chargeable resin can be used as compared with the case where only the macromonomer having the hydrocarbon skeleton is used as the dispersion stabilizer. When the particles are dispersed and polymerized, the polymerization stability can be improved and the aggregation of the particles during the polymerization can be avoided.

Further, the non-chargeable resin particles using only the silicone macromonomer as a dispersion stabilizer have a silicone chain derived from the silicone macromonomer on the surface thereof. On the other hand, in the non-chargeable resin particles in which the macromonomer having the hydrocarbon skeleton and the silicone macromonomer are used in combination as a dispersion stabilizer, a part of the silicone chain present on the surface of the non-chargeable resin particles is present. It has a structure replaced by the hydrocarbon molecular chain. By replacing a part of the silicone chain with the above hydrocarbon molecular chain, aggregation of the non-chargeable resin particles can be avoided and the pseudoplasticity of the non-chargeable resin particles can be improved, so that the desired viscosity of the non-chargeable resin particles can be obtained. The characteristics (characteristics in which the viscosity ratio η ₁₀ / η ₁₀₀₀ satisfies 1.2 ≦ η ₁₀ / η ₁₀₀₀ ≦ 10) can be more reliably imparted.

  As the dispersion stabilizer, a macromonomer having the hydrocarbon skeleton, a macromonomer having the hydrocarbon skeleton, and a macromonomer having different dispersion characteristics from the silicone macromonomer but different from the silicone macromonomer are used in combination. Even in this case, there is a possibility that the same effect can be obtained as when the macromonomer having the hydrocarbon skeleton and the silicone macromonomer are used in combination.

  As the silicone macromonomer, various compounds having an ethylenically unsaturated group at one end and having a silicone unit (organosiloxane unit such as polydimethylsiloxane unit) can be used.

  The silicone macromonomer is preferably a silicone macromonomer having no polar group. Thereby, the chargeability of the non-chargeable resin particles can be further reduced. Examples of the silicone macromonomer having no polar group include those having a structure represented by the following general formula (1).

(In the above formula, R ¹ represents a hydrogen atom or a methyl group, R ² represents an alkylene group having 2 to 4 carbon atoms, and R ³ are the same as or different from each other, and each represents an alkyl group having 1 to 4 carbon atoms or Represents a phenyl group, and n represents a positive integer)
Examples of the alkylene group having 2 to 4 carbon atoms represented by R ² in the general formula (1) include an ethylene group, an n-propylene group, a trimethylene group, a tetramethylene group, and an ethylethylene group. Examples of the alkyl group having 1 to 4 carbon atoms represented by R ³ in the general formula (1) include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, and tert-butyl. Groups and the like.

  Specifically, as the silicone macromonomer having the structure represented by the general formula (1), for example, α-butyl-ω- (3-methacryloxypropyl) polydimethylsiloxane (for example, “manufactured by JNC Corporation” Silaplane (registered trademark) FM-0711 "," Silaplane (registered trademark) FM-0721 "," Silaplane (registered trademark) FM-0725 "(trade name)) and the like. 1 type may be used for the said silicone macromonomer, and 2 or more types may be used together.

  The number average molecular weight of the silicone macromonomer is preferably in the range of 500 to 40000, and more preferably in the range of 1000 to 20000. N in the general formula (1) is preferably a number that can give a number average molecular weight within this range. N in the general formula (1) is preferably in the range of 3 to 500, and more preferably in the range of 10 to 250.

The amount of the silicone macromonomer used is preferably in the range of 0.1 to 200 parts by weight and in the range of 0.1 to 100 parts by weight with respect to 100 parts by weight of the other vinyl monomer. It is more preferable that If the amount of the silicone macromonomer used is less than 0.1 parts by weight relative to 100 parts by weight of the other vinyl monomer, the amount of silicone chains introduced to the surface of the non-chargeable resin particles is reduced. When the chargeable resin particles are dispersed in a nonpolar solvent to form a nonchargeable resin particle dispersion, the nonchargeable resin particles may aggregate. On the other hand, when the amount of the silicone macromonomer used exceeds 200 parts by weight with respect to 100 parts by weight of the other vinyl monomer, excessive silicone chains are introduced onto the surface of the non-chargeable resin particles. When the non-chargeable resin particle dispersion is obtained by dispersing the non-conductive resin particles in a non-polar solvent, the non-chargeable resin particle dispersion has a desired viscosity characteristic (viscosity ratio η ₁₀ / η ₁₀₀₀ is 1.2 ≦ η ₁₀ / η ₁₀₀₀ ≦ 10) may not be imparted.

  The use amount of the macromonomer having the hydrocarbon skeleton and the silicone macromonomer is in the range of 0.1 to 15 parts by weight of the macromonomer having the hydrocarbon skeleton with respect to 100 parts by weight of the other vinyl monomer. It is preferable that the silicone macromonomer is in the range of 0.1 to 200 parts by weight with respect to 100 parts by weight of the other vinyl monomer, and 100 weights of the other vinyl monomer. The macromonomer having the hydrocarbon skeleton with respect to parts is in the range of 0.1 to 10 parts by weight, and the silicone macromonomer is 0.1 to 100 parts by weight with respect to 100 parts by weight of the other vinyl monomer. More preferably within the range of 100 parts by weight.

  The weight ratio of the macromonomer having the hydrocarbon skeleton and the silicone macromonomer used (weight of the macromonomer having a hydrocarbon skeleton / weight of the silicone macromonomer) is 1.0 / 100 to 100 / It is preferable to be within the range of 100.

[1-2. Aromatic vinyl monomer having no polar group]
The other vinyl monomer is preferably an aromatic vinyl monomer having no polar group. Thereby, the chargeability of the non-chargeable resin particles can be further reduced. As a result, when the non-chargeable resin particles of the present invention are used in an electrophoretic display device in combination with the chargeable colored resin particles, aggregation of the non-chargeable resin particles and the chargeable colored resin particles, or the chargeable colored resin Generation of color mixing due to migration of the non-chargeable resin particles in the same direction as the migration direction of the particles can be further suppressed.

  The aromatic vinyl monomer having no polar group is a compound having at least one ethylenically unsaturated group (in a broad sense) and having an aromatic group (aromatic vinyl monomer). And a compound having no polar group. The aromatic vinyl monomer having no polar group may be monofunctional or crosslinkable (polyfunctional). Here, “crosslinkable” means having two or more ethylenically unsaturated groups.

  Examples of the monofunctional aromatic vinyl monomer having no polar group include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, o-ethylstyrene, m-ethylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, on-butylstyrene, mn-butylstyrene, pn-butylstyrene, o-tert-butylstyrene, m-tert-butylstyrene, p-tert -Butyl styrene, on-hexyl styrene, mn-hexyl styrene, pn-hexyl styrene, on-octyl styrene, mn-octyl styrene, pn-octyl styrene, on- Nonyl styrene, mn-nonyl styrene, pn-nonyl styrene, on-decyl styrene, mn-decyl styrene, p n-decylstyrene, on-dodecylstyrene, mn-dodecylstyrene, pn-dodecylstyrene, n-methoxystyrene, o-phenylstyrene, m-phenylstyrene, p-phenylstyrene, 1-vinylnaphthalene 2-vinylnaphthalene, benzyl methacrylate, benzyl acrylate, phenyl methacrylate, phenyl acrylate, naphthyl methacrylate, naphthyl acrylate, biphenyl methacrylate, biphenyl acrylate, vinyl benzoate, and derivatives thereof.

  Examples of the crosslinkable aromatic vinyl monomer having no polar group include aromatic divinyl monomers such as divinylbenzene, divinylnaphthalene, divinylbiphenyl, diethylene glycol di (meth) acrylate phthalate, and derivatives thereof. And monomers. One type of aromatic vinyl monomer having no polar group may be used, or two or more types may be used in combination.

  The aromatic vinyl monomer having no polar group is preferably an aromatic vinyl monomer having neither a polar group nor a carbonyl group. Thereby, the chargeability of the non-chargeable resin particles can be further reduced. As a result, when the non-chargeable resin particles of the present invention are used in an electrophoretic display device in combination with the chargeable colored resin particles, aggregation of the non-chargeable resin particles and the chargeable colored resin particles, or the chargeable colored resin Generation of color mixing due to migration of the non-chargeable resin particles in the same direction as the migration direction of the particles can be further suppressed.

[1-3. Vinyl monomers other than aromatic vinyl monomers having no polar group]
The other vinyl monomer may contain a vinyl monomer other than the aromatic vinyl monomer having no other polar group. Examples of the vinyl monomer other than the aromatic vinyl monomer having no other polar group include compounds other than the aromatic vinyl monomer having no polar group, and at least one ethylenic monomer. Any compound having a saturated group may be used, and (1) a monofunctional vinyl monomer having no polar group and not an aromatic vinyl monomer, and (2) a monomer having a polar group. A functional vinyl monomer, (3) a crosslinkable vinyl monomer having no polar group and not an aromatic vinyl monomer, and (4) a crosslinkable vinyl having a polar group System monomers (however, (1) to (4) are not the dispersion stabilizers) can be used.

  Examples of the monofunctional vinyl monomer having no polar group (1) include olefins such as isoprene, isobutene, propylene and ethylene; vinyl ethers such as vinyl methyl ether, vinyl ethyl ether and vinyl isobutyl ether. Carboxylic acid vinyl esters such as vinyl acetate, vinyl propionate and vinyl butyrate; methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, propyl acrylate, n-octyl acrylate, dodecyl acrylate , 2-ethylhexyl acrylate, stearyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, 2-methacrylic acid 2- Hexyl, alpha-methylene aliphatic monocarboxylic acid esters such as stearyl methacrylate; vinyl methyl ketone, vinyl hexyl ketone, and vinyl ketones such as methyl isopropenyl ketone. As the monofunctional vinyl monomer (1), one type may be used, or two or more types may be used in combination.

  Examples of the monofunctional vinyl monomer having a polar group (2) include styrene derivatives such as p-chlorostyrene and 3,4-dichlorostyrene; vinyl chloride, vinylidene chloride, vinyl bromide, fluorine Vinyl halides such as vinyl chloride; 2-chloroethyl acrylate, methyl α-chloroacrylate, dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, diethylaminoethyl acrylate, diethylaminoethyl methacrylate, 2-hydroxyethyl methacrylate , Α-methylene aliphatic monocarboxylic acid esters such as 2-hydroxypropyl methacrylate; acrylic acid derivatives such as acrylonitrile, methacrylonitrile, acrylamide, methacrylamide, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, etc. Or methacrylic acid derivatives (excluding α-methylene aliphatic monocarboxylic acid esters); fatty acids having an ethylenically unsaturated group such as acrylic acid, methacrylic acid, maleic acid, fumaric acid; N-vinylpyrrole, N- Examples thereof include N-vinyl nitrogen-containing heterocyclic compounds such as vinyl carbazole, N-vinyl indole and N-vinyl pyrrolidone. As the monofunctional vinyl monomer (2), one type may be used, or two or more types may be used in combination.

  Examples of the crosslinkable vinyl monomer having no polar group (3) include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, and tetradecaethylene. Glycol di (meth) acrylate, nonaethylene glycol di (meth) acrylate, tetradecaethylene glycol di (meth) acrylate, decaethylene glycol di (meth) acrylate, pentadecaethylene glycol di (meth) acrylate, 1,3-butane Diol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tetra (meth) ) Acrylate, caprolactone-modified dipentaerythritol hexa (meth) acrylate, caprolactone-modified hydroxypivalic acid ester neopentyl glycol diacrylate, and polyester acrylate (meth) acrylic acid ester monomer, and the like. In this application document, “(meth) acrylate” means acrylate or methacrylate, and “(meth) acryl” means acrylic or methacryl. As the crosslinkable vinyl monomer having no polar group (3), one kind may be used, or two or more kinds may be used in combination.

  Examples of the crosslinkable vinyl monomer having a polar group (4) include (meth) acrylic acid ester monomers such as glycerin di (meth) acrylate and urethane acrylate. As the crosslinkable vinyl monomer having a polar group (4), one kind may be used, or two or more kinds may be used in combination.

  The proportion of structural units derived from vinyl monomers having no polar group in the non-chargeable resin particles (corresponding to the proportion of vinyl monomers having no polar group in the monomer mixture) is 50. It is preferably at least wt%, more preferably at least 80 wt%, and most preferably at 100 wt%. Thereby, since the number of polar groups contained in the non-chargeable resin particles can be further reduced, the chargeability of the non-chargeable resin particles can be further reduced. As a result, when the non-chargeable resin particles of the present invention are used in an electrophoretic display device in combination with the chargeable colored resin particles, aggregation of the non-chargeable resin particles and the chargeable colored resin particles, or the chargeable colored resin Generation of color mixing due to migration of the non-chargeable resin particles in the same direction as the migration direction of the particles can be further suppressed.

  The proportion of vinyl monomers not having a polar group in the other vinyl monomers (particularly aromatic vinyl monomers having no polar group) is preferably 50% by weight or more, It is more preferably 80% by weight or more, and most preferably 100% by weight. Thereby, since the number of polar groups contained in the non-chargeable resin particles can be further reduced, the chargeability of the non-chargeable resin particles can be further reduced. As a result, when the non-chargeable resin particles of the present invention are used in an electrophoretic display device in combination with the chargeable colored resin particles, aggregation of the non-chargeable resin particles and the chargeable colored resin particles, or the chargeable colored resin Generation of color mixing due to migration of the non-chargeable resin particles in the same direction as the migration direction of the particles can be further suppressed.

[2. Other additives]
For the non-chargeable resin particles, a chain transfer agent, a pigment particle (pigment), a dye, a stabilizer, an ultraviolet absorber, an antifoaming agent, and a thickening agent may be used as long as the effects of the present invention are not impaired. , Heat stabilizers, leveling agents, lubricants, antistatic agents and the like may be used.

  The chain transfer agent can be used during the polymerization of the vinyl monomer. The chain transfer agent is not particularly limited, and examples thereof include alkyl mercaptans such as n-hexyl mercaptan, n-octyl mercaptan, tert-octyl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan, α-methylstyrene dimer, 2 , 6-di-tert-butyl-4-methylphenol, styrenated phenol and other phenolic compounds, allyl alcohol and other allyl compounds, dichloromethane, dibromomethane, carbon tetrachloride and other halogenated hydrocarbon compounds. These may use 1 type and may use 2 or more types together.

  The pigment particle is not particularly limited as long as it is a pigment particle used as a pigment in the technical field. For example, iron oxide pigments such as mica-like iron oxide and iron black, lead oxides such as red lead and yellow lead Pigment: Titanium oxide pigments such as titanium white (rutile titanium oxide), titanium yellow and titanium black; Cobalt oxide; Zinc oxide pigments such as zinc yellow; Molybdenum oxide pigments such as molybdenum red and molybdenum white Is mentioned. When the non-chargeable resin particles of the present invention are used to display the background of an electrophoretic display device, a white background display such as paper can be realized. As the pigment particles, titanium white, molybdenum white, etc. It is preferable to use white pigment particles, and it is more preferable to use titanium white particles as the pigment particles because a white background display with better whiteness can be realized. The pigment particles may be used alone or in combination of two or more.

[3. Method for producing non-chargeable resin particles]
The non-chargeable resin particles of the present invention can be obtained by polymerizing the vinyl monomer by a known polymerization method such as suspension polymerization, emulsion polymerization or dispersion polymerization. Among these polymerization methods, dispersion polymerization is preferable in that the particle diameter can be easily controlled and non-chargeable resin particles can be easily obtained. Hereinafter, although mainly the case of dispersion polymerization will be described, the present invention is not limited thereto.

  When the non-chargeable resin particles of the present invention are produced by dispersion polymerization, for example, the above-mentioned vinyl monomer is dispersed in a non-polar solvent, a polymerization initiator is added, and polymerization is performed under predetermined conditions. Resin particles can be produced. In order to prevent coalescence of particles during the dispersion polymerization, the dispersion polymerization is preferably performed under irradiation of ultrasonic waves or stirring with a mechanical stirring device such as a magnetic stirrer. Also. The dispersion polymerization may be performed by using both ultrasonic irradiation and stirring by a mechanical stirring device such as a magnetic stirrer.

  The reaction temperature and time in the polymerization of the vinyl monomer are not particularly limited, and can be adjusted as appropriate depending on the type and amount of the polymerization initiator used and the amount of the vinyl monomer used for the polymerization. Good. The polymerization reaction temperature is preferably in the range of 40 to 120 ° C, and more preferably in the range of 40 to 80 ° C. The polymerization reaction time is preferably in the range of 0.5 to 50 hours, and more preferably in the range of 2 to 24 hours.

  In addition, the polymerization of the vinyl monomer may be performed in an air atmosphere or an inert gas atmosphere. In order to prevent a polymerization rate delay and polymerization inhibition due to oxygen in the atmosphere. It is preferable to carry out in an inert gas atmosphere. Examples of such an inert gas include nitrogen gas and argon gas, and nitrogen gas is preferable from the viewpoint of economy.

[4. Polymerization initiator)
As a polymerization initiator used for the polymerization for forming the non-chargeable resin particles, an oil-soluble peroxide polymerization initiator, an azo polymerization initiator, or the like can be used. Specific examples of the polymerization initiator include benzoyl peroxide, dilauroyl peroxide (lauroyl peroxide), octanoyl peroxide, o-chlorobenzoyl peroxide, o-methoxybenzoyl peroxide, methyl ethyl ketone peroxide, Peroxide polymerization initiators such as diisopropyl peroxydicarbonate, cumene hydroperoxide, cyclohexanone peroxide, tert-butyl hydroperoxide, diisopropylbenzene hydroperoxide; 2,2′-azobisisobutyronitrile, 2 2,2′-azobis (2,4-dimethylvaleronitrile), 2,2′-azobis (2,3-dimethylbutyronitrile), 2,2′-azobis (2-methylbutyronitrile), 2,2 '-Azobis (2,3,3-trimethyl Tyronitrile), 2,2′-azobis (2-isopropylbutyronitrile), 1,1′-azobis (cyclohexane-1-carbonitrile), 2,2′-azobis (4-methoxy-2,4-dimethylvalero) Nitrile), 2- (carbamoylazo) isobutyronitrile, 4,4′-azobis (4-cyanovaleric acid), dimethyl-2,2′-azobisisobutyrate, and other azo polymerization initiators. . Examples of the polymerization initiator include polymerization initiators having no polar group such as cyano group, carboxyl group, amide group, ammonium group and sulfonic acid group, for example, organic peroxides such as benzoyl peroxide and dilauroyl peroxide. Polymerization initiators and azo polymerization initiators such as dimethyl-2,2-azobis (2-methylpropionate) are preferred. The said polymerization initiator may use 1 type and may use 2 or more types together.

[5. Nonpolar solvent)
Examples of the nonpolar solvent include paraffinic hydrocarbons such as pentane, hexane, heptane, octane, nonane, decane, and dodecane; isoparaffinic hydrocarbons such as isohexane, isooctane, and isododecane: alkyl naphthenic hydrocarbons such as liquid paraffin A dialkyl silicone oil such as dimethyl silicone oil; an alkylphenyl silicone oil such as methylphenyl silicone oil (phenylmethyl silicone oil); a silicone oil such as cyclic polydialkylsiloxane and cyclic polyalkylphenylsiloxane; Of these, taking into consideration the environmental impact of the working environment, alkyl naphthenic hydrocarbons such as liquid paraffin; dialkyl silicone oils such as dimethyl silicone oil, and alkyl phenyls such as methyl phenyl silicone oil (phenyl methyl silicone oil) Silicone oil; cyclic polydialkylsiloxane, cyclic polyalkylphenylsiloxane and the like are preferable as the nonpolar solvent. The said nonpolar solvent may use 1 type and may use 2 or more types together. In order to efficiently disperse the pigment particles and the surface treatment agent, the silicone oil is preferably a silicone oil having a kinematic viscosity of 100 cSt or less measured by a measurement method defined in JIS K 2283.

[6. Properties of non-chargeable resin particles)
As described above, the non-chargeable resin particles have a pair of mutually parallel distances of 50 μm in a state of being dispersed in a silicone oil having a kinematic viscosity of 100 cSt or less at a solid concentration of 30% by weight. The charge amount measured when a voltage of 15 V is applied for 60 seconds sandwiched between flat ITO electrodes is 5 nC / cm ² or less. The non-chargeable resin particles have a charge amount measured under the above-mentioned conditions of 5 nC / cm ² or less, so that when they are used in an electrophoretic display device in combination with chargeable colored resin particles, Generation of color mixing due to aggregation of the chargeable resin particles and the chargeable colored resin particles, or migration of the non-chargeable resin particles in the same direction as the migration direction of the chargeable colored resin particles can be suppressed, and a good display can be realized. The non-chargeable resin particles preferably have a charge amount measured under the above conditions of 4 nC / cm ² or less.

The non-chargeable resin particles are 25 at a shear rate of 10 s ^-1 and 1000 s ^-1 of a non-chargeable resin particle dispersion in which the non-charge resin particles are dispersed in a non-polar solvent at a solid content concentration of 30% by weight. ℃ viscosity at the when the eta ₁₀ and eta ₁₀₀₀ respectively,
1.2 ≦ η ₁₀ / η ₁₀₀₀ ≦ 10
Viscosity characteristics satisfying When the ratio η ₁₀ / η ₁₀₀₀ of the viscosity at a shear rate of 10 s ⁻¹ and _{1000 s} ⁻¹ of the non-chargeable resin particle dispersion is 1.2 or more, the non-chargeable resin particle dispersion becomes a chargeable colored resin. When used in an electrophoretic display device in combination with particles, the viscosity of the non-charged resin particle dispersion increases (compared to the time of migration) after the migration of the charged colored resin particles (at the time of non-migration). By doing so, sedimentation of the chargeable colored resin particles and the non-chargeable resin particles can be suppressed, so that the memory performance of the image can be improved. In the non-chargeable resin particles, the viscosity ratio η ₁₀ / η _{1000 at} the shear rates of 10 s ⁻¹ and _{1000 s} ⁻¹ of the non-chargeable resin particle dispersion is more preferably 1.3 or more. More preferably, η ₁₀ / η ₁₀₀₀ is 1.4 or more.

When the ratio of viscosity η ₁₀ / η _{1000 at} a shear rate of 10 s ^-1 and _{1000 s} ^-1 of the non-chargeable resin particle dispersion exceeds 10, the non-chargeable resin particle dispersion is combined with the chargeable colored resin particles. When used in an electrophoretic display device, the viscosity of the non-charged resin particle dispersion is too high (compared to migration) before the migration of the chargeable colored resin particles (during non-migration). The migration of the colored resin particles is difficult to start, and as a result, the electric field response of the charged colored resin particles may be lowered. In the non-chargeable resin particles, the viscosity ratio η ₁₀ / η _{1000 at} the shear rates of 10 s ⁻¹ and _{1000 s} ⁻¹ of the non-chargeable resin particle dispersion is more preferably 7 or less, and the viscosity ratio η ₁₀ More preferably, / η ₁₀₀₀ is 5 or less.

The viscosity η _{10 at} a shear rate of 10 s ⁻¹ of the non-chargeable resin particle dispersion in which the non-chargeable resin particles are dispersed in a non-polar solvent is preferably in an appropriate range. The viscosity η ₁₀ measured under the condition that the solid content concentration of the resin particle dispersion is 30% by weight is preferably in the range of 7 to 50 cP. When the viscosity η ₁₀ is less than 7 cP, the memory property of the image can be sufficiently improved when the non-chargeable resin particle dispersion is combined with the chargeable colored resin particles and used in an electrophoretic display device. There are things that cannot be done. When the viscosity η ₁₀ exceeds 50 cP, when the non-chargeable resin particle dispersion is combined with the chargeable colored resin particles and used in the electrophoretic display device, before the chargeable colored resin particles are migrated (during non-electrophoresis). ), The viscosity of the non-chargeable resin particle dispersion is too high, and the migration of the charged colored resin particles is difficult to start, and as a result, the electric field response of the charged colored resin particles may be lowered. The viscosity η _{10 at} a shear rate of 10 s ⁻¹ of the non-charged resin particle dispersion in which the non-charged resin particles are dispersed in a non-polar solvent is more preferably in the range of 7 to 30 cP.

The non-charged resin particle dispersion obtained by dispersing the non-charged resin particles in a non-polar solvent preferably has a low viscosity η _{1000 at} a shear rate of _{1000 s} ⁻¹ , for example, the non-charged resin particle dispersion It is preferable that the viscosity η ₁₀₀₀ measured under a solid content concentration of 30% by weight is less than 20 cP. When the viscosity η ₁₀₀₀ is 20 cP or more, when the non-chargeable resin particle dispersion is combined with the chargeable colored resin particles and used in an electrophoretic display device, the chargeable colored resin particles are uncharged during migration. Since the viscosity of the conductive resin particle dispersion is too high, the migration speed of the chargeable colored resin particles becomes slow, and as a result, the electric field responsiveness of the migration of the chargeable colored resin particles may be lowered. The viscosity η _{1000 at} a shear rate of _{1000 s} ⁻¹ of the non-chargeable resin particle dispersion in which the non-charge resin particles are dispersed in a non-polar solvent is more preferably less than 15 cP.

  The average particle diameter of the non-chargeable resin particles is preferably in the range of 50 to 1000 nm, more preferably in the range of 100 to 1000 nm, and still more preferably in the range of 200 to 800 nm. When the average particle diameter of the non-chargeable resin particles is less than 50 nm, the viscosity of the reaction system during polymerization to form the non-chargeable resin particles (due to dispersion polymerization of the vinyl monomer in a nonpolar solvent). When the non-chargeable resin particles are formed, the viscosity of the non-polar solvent is increased, and as a result, the non-chargeable resin particles having a stable average particle diameter may not be produced. On the other hand, when the average particle diameter of the non-chargeable resin particles exceeds 1000 nm, the non-chargeable resin particles are dispersed in a non-polar solvent to form a non-chargeable resin particle dispersion. The dispersion stability of the resin may deteriorate.

  A smaller sedimentation rate of the non-chargeable resin particles in the dispersion medium is preferable. Specifically, when silicone oil (manufactured by Shin-Etsu Chemical Co., Ltd., trade name “KF-96L-2cs”, kinematic viscosity at 25 ° C.) is used as the dispersion medium, the solid content of the non-chargeable resin particles On the condition that the concentration is 30% by weight, the sedimentation rate of the non-chargeable resin particles in the silicone oil is preferably 0.8 μm / s or less, and more preferably 0.7 μm / s or less. If the settling speed of the non-chargeable resin particles exceeds 0.8 μm / s, it is impossible to maintain the memory properties of the image over a long period of time when the non-chargeable resin particles are used in an electrophoretic display device. There is. In addition, in this application document, the sedimentation rate of non-chargeable resin particles shall mean the sedimentation rate measured with the measuring method as described in the Example section.

  When the non-chargeable resin particles do not contain pigment particles, they are usually observed as white particles when dispersed in a non-polar solvent. Therefore, as non-chargeable resin particles for electrophoretic display devices, It can be used. On the other hand, when the non-chargeable resin particles include pigment particles, they exhibit colors derived from the pigment particles when dispersed in a non-polar solvent. Therefore, various colors of non-chargeable resins for electrophoretic display devices are used. It can be used as particles.

[Non-chargeable resin particle dispersion]
The non-chargeable resin particle dispersion of the present invention contains a non-polar solvent and the non-chargeable resin particles of the present invention dispersed in the non-polar solvent.

  As the non-polar solvent, any of those mentioned in the section “5. Non-polar solvent” can be used, and silicone oil is preferred in consideration of the influence on the environment such as the working environment. In order to promote the dispersion of the non-chargeable resin particles, the silicone oil is preferably a silicone oil having a kinematic viscosity of 100 cSt or less measured by a measurement method defined in JIS K 2283.

  The ratio of the non-chargeable resin particles to the nonpolar solvent is not particularly limited, and can be appropriately set according to the use of the non-chargeable resin particle dispersion. For example, when the non-charged resin particle dispersion is used for an electrophoretic display device, the content of the non-charged resin particles in the non-charged resin particle dispersion is preferably 2 to 60% by weight, More preferably, it is in the range of 5 to 50% by weight.

  The non-chargeable resin particle dispersion may be blended with known additives as long as the effects of the present invention are not impaired.

[Electrophoretic display device]
The electrophoretic display device of the present invention uses the non-chargeable resin particle dispersion of the present invention. The electrophoretic display device of the present invention includes the non-chargeable resin particle dispersion of the present invention, and the non-charged resin particle dispersion is different in color tone from the non-chargeable resin particles dispersed in the non-polar solvent. It further includes chargeable colored resin particles having the following.

  The electrophoretic display device displays an image using electrophoresis of chargeable colored resin particles. Specifically, in the electrophoretic display device, the non-chargeable resin particles develop a base color (a color corresponding to paper, for example, white, black, etc.), and the charged colored resin particles are electrophoresed by electrophoresis. Corresponds to paper on which characters and / or pictures are drawn by developing a color different from the base color (in a desired shape) at a position (color corresponding to letters and / or pictures drawn on paper) Display the image to be played. In the case of an electrophoretic display device for monochromatic display, for example, white non-chargeable resin particles and black chargeable colored resin particles may be used in combination. In the case of an electrophoretic display device for color display, for example, a combination of white non-chargeable resin particles, red chargeable colored resin particles, green chargeable colored resin particles, and blue chargeable colored resin particles. Can be used.

  The content of the chargeable colored resin particles in the nonchargeable resin particle dispersion is 0.2 to 50 parts by weight with respect to 100 parts by weight of components other than the chargeable colored resin particles in the nonchargeable resin particle dispersion. Is preferably in the range of 0.5 to 40 parts by weight.

  The configuration of the electrophoretic display device is not particularly limited, for example, a configuration in which a display layer made of the non-chargeable resin particle dispersion is sandwiched between a pair of opposing substrates each having an electrode, There is a configuration in which at least one of the substrates is a transparent substrate having a transparent electrode such as an ITO electrode. In this configuration, by applying a voltage between the electrode of one substrate and the electrode of the other substrate, the chargeable colored resin particles are electrophoresed on the one substrate side according to the polarity of the applied voltage. (Moving. In the electrophoretic display device, an image can be displayed by using a plurality of pixel electrodes in which electrodes on at least one substrate are arranged in a matrix and controlling the voltage for each pixel electrode. The non-chargeable resin particle dispersion is preferably sealed in a plurality of transparent organic polymer microcapsules, and each microcapsule is disposed adjacent to each pixel electrode.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention concretely, this invention is not limited by these Examples.

  First, the measurement method of the average particle diameter, the charge amount, the sedimentation speed and the viscosity of the non-chargeable resin particles and the evaluation method of the memory property of the image in the following Examples and Comparative Examples will be described.

[Measurement method of average particle diameter of non-chargeable resin particles]
In the following examples and comparative examples, the Z-average particle diameter of the non-chargeable resin particles is measured using the dynamic light scattering method as follows, and the measured Z-average particle diameter is used for the non-chargeable resin particles. The average particle size was taken.

  That is, first, a silicone oil dispersion of non-charged resin particles having a solid content concentration of 30% by weight obtained in the following Examples and Comparative Examples (non-charged resin particles were dispersed in silicone oil as a nonpolar solvent). Non-chargeable resin particle dispersion) is diluted with silicone oil (manufactured by Shin-Etsu Chemical Co., Ltd., trade name “KF-96L-2cs”, kinematic viscosity at 25 ° C. 2 cSt, hereinafter referred to as “silicone oil 2CS”), A silicone oil dispersion having a solid content of 0.1% by weight was prepared. This silicone oil dispersion having a solid content concentration of 0.1% by weight was irradiated with laser light, and the intensity of scattered light scattered from the non-chargeable resin particles was measured with a time change in units of microseconds. Then, the scattering intensity distribution resulting from the detected non-chargeable resin particles was applied to a normal distribution, and the Z-average particle diameter of the non-chargeable resin particles was determined by a cumulant analysis method for calculating the average particle diameter.

  The measurement of the Z average particle diameter can be easily performed with a commercially available particle diameter measuring apparatus. In the following Examples and Comparative Examples, the Z average particle size was measured using a particle size measuring device (trade name “Zetasizer Nano ZS”) manufactured by Malvern Instruments Ltd. Usually, a commercially available particle size measurement apparatus is equipped with data analysis software, and the data analysis software can automatically calculate the Z-average particle size by analyzing the measurement data.

[Measurement method of charge amount of non-chargeable resin particles]
A silicone oil dispersion of non-chargeable resin particles having a solid content concentration of 30% by weight obtained in the following Examples and Comparative Examples was used as a measurement sample.

  Moreover, the jig shown in FIG. 1 was produced as follows. First, a glass plate (width 20 mm, length 100 mm, thickness 0.7 mm, manufactured by Matsunami Glass Industrial Co., Ltd., trade name “EAGLE XG”, which is a pair of rectangular flat plates coated with ITO (flat ITO electrode) on one side. ", Hereinafter referred to as" ITO coated glass plate "). As shown in FIG. 1, one end (45 mm in length) of the pair of ITO coated glass substrates 11 in the length direction is parallel to each other, and the respective ITO coated surfaces 12 are inside. In this state, a jig having a distance of 50 μm was produced by stacking two spacers 14 each having a thickness of 50 μm (the spacer 14 was sandwiched between the ITO-coated glass substrates 11). As the two spacers 14 having a thickness of 50 μm, two “Teflon (registered trademark)” (polytetrafluoroethylene) films (length: 20 mm, width: 10 mm) having a thickness of 50 μm were used. These “Teflon (registered trademark)” The film was affixed to both end portions (dimension 10 mm along the length direction of the ITO coated glass substrate 11) along the length direction of the one end portion (length 45 mm) of one ITO coated glass substrate 11. The jig has a measurement sample injection portion 13 that is a gap having a width of 25 mm, a length of 20 mm, and a thickness of 50 μm between the ITO-coated surfaces 12 of the two ITO-coated glass substrates 11.

Next, the measurement sample was infiltrated into the measurement sample injection portion 13 of the jig by capillary action using a syringe. Next, the ITO coated surfaces 12 at both ends in the length direction of the jig are connected to a charge measuring device (trade name “6514 type programmable electrometer” manufactured by Keithley Instruments Inc.), and the ITO coated surface 12 The amount of charge (nC) was measured by applying a voltage of +15 V between them for 60 seconds. The measured value of the obtained charge amount is divided by the area (cm ² ) of the ITO coat surface 12 facing the measurement sample injection portion 13, and this is charged (charge density per unit area) (nC / cm ² ). ).

[Method for evaluating sedimentation rate of non-chargeable resin particles]
The “dispersion stability” of the non-chargeable resin particles referred to in the present invention was evaluated using the sedimentation rate of the non-chargeable resin particles in the silicone oil. The sedimentation rate of the uncharged resin particles in the silicone oil was measured using a method called a light transmission centrifugal sedimentation method.

  Specifically, a sample cell to which a silicone oil dispersion of non-chargeable resin particles having a solid content concentration of 30% by weight obtained in Examples and Comparative Examples was rotated at a high speed with a centrifugal acceleration of 1000 × g, The sedimentation rate of the non-chargeable resin particles was calculated by analyzing the separation phenomenon of the particles by the elapsed time.

  This sedimentation rate can be easily measured with a commercially available measuring device such as “LUMiSize 611” of LUM GmbH (LUM GmbH) used in Examples and Comparative Examples. Usually, a commercially available measuring apparatus is equipped with data analysis software, and the commercially available measuring apparatus can calculate the sedimentation velocity of particles by automatically analyzing the measurement data with the data analysis software.

[Method for measuring viscosity of non-chargeable resin particle dispersion]
In the following examples and comparative examples, the viscosity of the non-chargeable resin particle dispersion was measured as follows. The non-chargeable resin particle dispersion (silicone oil dispersion of non-chargeable resin particles) having a solid content concentration of 30% by weight obtained in the following Examples and Comparative Examples is set to have a shear rate of 10 s ⁻¹ at 25 ° C. The viscosity η ₁₀ of the non-chargeable resin particle dispersion at a shear rate of 10 s ⁻¹ was measured from the pressure drop at that time. Further, the shear rate the antistatic resin particle dispersion than to make a 1000 s ^-1 in the same manner, the viscosity was measured eta ₁₀₀₀ of the antistatic resin particle dispersion at a shear rate of 1000 s ^-1 .

  This viscosity measurement can be easily performed with a commercially available measuring apparatus such as a portable micro sample viscometer “μVISC” (trade name) manufactured by RheoSense Inc. In the comparative example, the portable micro sample viscometer “μVISC” was used.

[Evaluation Method for Image Memory Properties of Non-Charging Resin Particle Dispersion Containing Charging Colored Resin Particles]
With respect to the silicone oil dispersion of non-chargeable resin particles obtained in the following examples and comparative examples, the content of the non-chargeable resin particles and the red chargeable colored resin particles in the silicone oil dispersion is 27 wt. % And 9% by weight, the red chargeable colored resin particles obtained in the following production examples were added, and as a nonchargeable resin particle dispersion containing the chargeable colored resin particles, the nonchargeable resin particles and A silicone oil dispersion of red chargeable colored resin particles was obtained. This silicone oil dispersion was used as a sample for image memory property evaluation.

  Next, a glass plate (width 20 mm, length 100 mm, thickness 0.7 mm, Matsunami Glass Industrial Co., Ltd., trade name “EAGLE”) is a pair of rectangular flat plates coated with ITO (flat ITO electrode) on one side. XG ", hereinafter referred to as" ITO coated glass plate "). As shown in FIG. 1, one end (45 mm in length) of the pair of ITO coated glass substrates 11 in the length direction is parallel to each other, and the respective ITO coated surfaces 12 are inside. In such a state, a jig having a distance of 100 μm between the ITO-coated glass substrates 11 was produced by stacking the two spacers 14 having a thickness of 100 μm. The non-chargeable resin particles and the red charge are placed on the measurement sample injection portion 13 (width 25 mm, length 20 mm, thickness 100 μm), which is a gap between the ITO-coated surfaces 12 of the two ITO-coated glass substrates 11 of the jig. A silicone oil dispersion of conductive colored resin particles was inserted. The jig is placed so that the ITO-coated glass substrate 11 is horizontal, a voltage of −100 V is applied to the upper ITO-coated glass substrate 11 for 10 seconds, and the red chargeable colored resin particles are placed on the upper ITO-coated glass substrate. 11 was moved to the ITO coated surface 12.

The (chromaticity a ^* L ^* a ^* b ^* color system) a ₀ color of the display surface image displayed on the (upper surface) (of the entire red image) at the top of the ITO-coated glass substrate 11, Nippon Denshoku It was measured with a spectroscopic color meter (trade name “SE-2000”, manufactured by Kogyo Co., Ltd., measurement method: reflection mode, measurement diameter: 10 mmΦ to 6 mmΦ). After 60 minutes, the color a ₆₀ of the image displayed on the display surface of the upper ITO coated glass plate 11 was measured again in the same manner. From the obtained values of a ₀ and a ₆₀ , the change in color of the image in 10 minutes from the start of image display | a ₀ −a ₆₀ | = Δa
Was calculated. Then, the memory property of the image was evaluated according to the following evaluation criteria according to the magnitude of the value of Δa.

(Evaluation criteria)
When Δa ≦ 8, the memory property of the image is evaluated as “◯” (good), and when Δa> 8, the memory property of the image is evaluated as “×” (defective).

[Production Example of Charged Colored Resin Particles] (Production Method of Red Charged Colored Resin Particles)
183 parts by weight of methyl methacrylate (hereinafter abbreviated as “MMA”) and 17 parts by weight of pigment (trade name “Pigment. Red 177 Chromofine (registered trademark) Red 6605T”, manufactured by Dainichi Seika Co., Ltd.) The mixture was placed in a bead pod containing 5 mm zirconia beads and stirred for 12 hours to disperse the pigment in MMA to obtain a dispersion. Next, a part of the dispersion is weighed, and MMA, ethylene glycol dimethacrylate (hereinafter abbreviated as “EGDMA”), and diethylaminoethyl methacrylate (hereinafter abbreviated as “DEAEMA”) are added to the weighed dispersion. The MMA weight fraction is 90.0% by weight, the EGDMA weight fraction is 1.0% by weight, the DEAEMA weight fraction is 5.0% by weight, and the pigment weight fraction is 4.0% by weight. Thus, a polymerizable monomer composition was prepared.

To 100 parts by weight of this polymerizable monomer composition, 1.0 part by weight of 2,2′-azobis (2,4-dimethylvaleronitrile) (hereinafter abbreviated as “ABNV”) is added, and a single amount of ABNV is added. A polymerizable monomer composition containing ABNV was obtained by dissolving in a body (MMA, EGDMA, DEAEMA). Next, a dispersion in which 0.030% by weight of sodium lauryl benzene sulfonate as an anionic surfactant and 1.0% by weight of magnesium pyrophosphate as a suspension stabilizer are prepared in advance and dispersed in water. A polymerizable monomer composition containing ABNV was added to 500 parts by weight, and the mixture was stirred for 5 minutes at a stirring speed of 4000 rpm using a homomixer (manufactured by PRIMIX Corporation) to obtain a primary suspension. Next, a collision type disperser (trade name “Nanomizer (registered trademark) processor LD-500, manufactured by Nanomizer Co., Ltd.) is connected to the high-pressure homogenizer (trade name“ Nanomizer (registered trademark) LA-33 type ”, manufactured by Nanomizer Co., Ltd.). The primary suspension was treated at a primary pressure of 5 kg / cm ² to obtain a secondary suspension.

  The suspension was heated to 60 ° C. while uniformly stirring the whole in a nitrogen atmosphere, and polymerization was performed at 60 ° C. for 6 hours. Further, the suspension was heated to 105 ° C., and polymerization was continued at 105 ° C. for 1 hour to complete the polymerization. Next, the suspension was cooled to room temperature, and hydrochloric acid was added to dissolve magnesium pyrophosphate as a suspension stabilizer. Subsequently, solid-liquid separation and water washing were repeated, followed by drying with a hot air dryer at 70 ° C. for 24 hours to obtain red chargeable colored resin particles.

[Example 1]
In a separable flask having an internal volume of 1000 ml equipped with a stirrer, a reflux condenser, and a thermometer, an isoparaffinic hydrocarbon (made by Exxon Mobil Corporation) as a nonpolar solvent, trade name “ISOPAR (registered trademark)” ) M ”, initial boiling point 225 ° C.) 547 parts by weight, and 2.5 parts by weight of dilauroyl peroxide (manufactured by NOF Corporation, trade name“ Perroyl (registered trademark) L)) as a polymerization initiator, , 100 parts by weight of styrene as an aromatic vinyl monomer having no polar group (other vinyl monomers), terminal acrylated hydrogenated polyisoprene as a macromonomer having a hydrocarbon skeleton (manufactured by Kuraray Co., Ltd.) , Trade name “UC-102”, number average molecular weight 12000, hereinafter abbreviated as “UC-102”) 2.0 parts by weight, and silicone macromonomer JNC Co., Ltd., trade name "FM-0721", hereinafter referred to as "FM-0721") were added to 18.0 parts by weight. Next, the separable flask was immersed in a water bath at 65 ° C., the stirring rotation speed was set to 100 rpm, and dispersion polymerization was performed for 20 hours to obtain resin particles.

  After completion of the dispersion polymerization, resin particles were settled and separated from the contents of the separable flask by centrifugation, and the isolated resin particles were redispersed in silicone oil 2CS. The sedimentation and redispersion operations were repeated three times to wash the resin particles.

  The washed resin particles were dispersed in silicone oil 2CS to obtain a silicone oil dispersion (nonpolar solvent dispersion) of resin particles having a solid content concentration of 30% by weight.

  The obtained resin particles were observed as white particles in the silicone oil dispersion, and were usable as white particles (white non-chargeable resin particles) for electrophoretic display devices. Here, the resin particles were observed as white particles because light reflection occurred at the interface between the resin particles and the silicone oil because the resin particles and the silicone oil had different refractive indexes. . Moreover, the average particle diameter of the resin particles in the obtained silicone oil dispersion was 278 nm.

Further, the charge amount of the resin particles in the obtained silicone oil dispersion was 0.12 nC / cm ² , and thus the obtained resin particles were non-chargeable resin particles. Further, the sedimentation rate of the non-chargeable resin particles in the obtained silicone oil dispersion was as slow as 0.49 μm / s, and the obtained non-chargeable resin particles were non-chargeable resin particles having excellent dispersion stability. It was.

The obtained silicone oil dispersion had a viscosity η _{10 at} a shear rate of 10 s ⁻¹ of 12.5 cP, a viscosity η ₁₀₀₀ at a shear rate of _{1000 s} ⁻¹ of 6.8 cP, and the shear rate of The ratio η ₁₀ / η ₁₀₀₀ was 1.8. Moreover, when the non-chargeable resin particle dispersion containing the chargeable colored resin particles was prepared by the above-described method using the obtained silicone oil dispersion, and the memory property of the image was evaluated by the above-mentioned method, Δa was It was 5.9% and the memory property of the image was good.

[Example 2]
Resin particles were obtained in the same manner as in Example 1 except that 100 parts by weight of 2-vinylnaphthalene was used in place of 100 parts by weight of styrene as an aromatic vinyl monomer having no polar group. Further, a silicone oil dispersion of resin particles was obtained in the same manner as in Example 1 except that the resin particles were used.

  The obtained resin particles were observed as white particles in the silicone oil dispersion and could be used as white particles for electrophoretic display devices. Moreover, the average particle diameter of the resin particles in the obtained silicone oil dispersion was 298 nm.

Further, the charge amount of the resin particles in the obtained silicone oil dispersion was 0.55 nC / cm ² , and thus the obtained resin particles were non-chargeable resin particles. Further, the sedimentation rate of the non-chargeable resin particles in the obtained silicone oil dispersion was as low as 0.55 μm / s, and the obtained non-charged resin particles were non-charged resin particles having excellent dispersion stability. It was.

The obtained silicone oil dispersion had a viscosity η _{10 at} a shear rate of 10 s ⁻¹ of 11.1 cP, a viscosity η ₁₀₀₀ at a shear rate of _{1000 s} ⁻¹ of 6.5 cP, and the shear rate of The ratio η ₁₀ / η ₁₀₀₀ was 1.7. Moreover, when the non-chargeable resin particle dispersion containing the chargeable colored resin particles was prepared by the above-described method using the obtained silicone oil dispersion, and the memory property of the image was evaluated by the above-mentioned method, Δa was It was 6.0% and the image memory property was good.

Example 3
Instead of 100 parts by weight of styrene, 100 parts by weight of benzyl methacrylate was used as an aromatic vinyl monomer having no polar group, and the amount of dilauroyl peroxide was changed from 2.5 parts by weight to 5.0 parts by weight. In the same manner as in Example 1 except that the amount of UC-102 is changed from 2.0 parts by weight to 4.0 parts by weight and the amount of FM-0721 is changed from 18.0 parts by weight to 22.7 parts by weight. Thus, resin particles were obtained. Further, a silicone oil dispersion of resin particles was obtained in the same manner as in Example 1 except that the resin particles were used.

  The obtained resin particles were observed as white particles in the silicone oil dispersion and could be used as white particles for electrophoretic display devices. Moreover, the average particle diameter of the resin particles in the obtained silicone oil dispersion was 245 nm.

Further, the charge amount of the resin particles in the obtained silicone oil dispersion was 4.5 nC / cm ² , and thus the obtained resin particles were non-chargeable resin particles. Further, the sedimentation rate of the non-chargeable resin particles in the obtained silicone oil dispersion was as low as 0.59 μm / s, and the obtained non-charged resin particles were non-charged resin particles having excellent dispersion stability. It was.

The obtained silicone oil dispersion had a viscosity η _{10 at} a shear rate of 10 s ⁻¹ of 34.1 cP, a viscosity η ₁₀₀₀ at a shear rate of _{1000 s} ⁻¹ of 11.1 cP, and the shear rate of The ratio η ₁₀ / η ₁₀₀₀ was 3.1. Moreover, when the non-chargeable resin particle dispersion containing the chargeable colored resin particles was prepared by the above-described method using the obtained silicone oil dispersion, and the memory property of the image was evaluated by the above-mentioned method, Δa was It was 3.4% and the memory property of the image was good.

Example 4
The amount of dilauroyl peroxide described in Example 1 was changed from 2.5 parts by weight to 1.7 parts by weight, the amount of UC-102 was changed from 2.0 parts by weight to 4.0 parts by weight, and FM. Resin particles were obtained in the same manner as in Example 1 except that the amount of −0721 was changed from 18.0 parts by weight to 16.0 parts by weight. Further, a silicone oil dispersion of resin particles was obtained in the same manner as in Example 1 except that the resin particles were used.

  The obtained resin particles were observed as white particles in the silicone oil dispersion and could be used as white particles for electrophoretic display devices. Moreover, the average particle diameter of the resin particles in the obtained silicone oil dispersion was 314 nm.

Further, the charge amount of the resin particles in the obtained silicone oil dispersion was 0.40 nC / cm ² , and thus the obtained resin particles were non-chargeable resin particles. Further, the sedimentation rate of the non-chargeable resin particles in the obtained silicone oil dispersion was as slow as 0.34 μm / s, and the obtained non-chargeable resin particles were non-charged resin particles having excellent dispersion stability. It was.

The obtained silicone oil dispersion had a viscosity η _{10 at} a shear rate of 10 s ⁻¹ of 26.1 cP, a viscosity η ₁₀₀₀ at a shear rate of _{1000 s} ⁻¹ of 10.2 cP, and the shear rate of The ratio η ₁₀ / η ₁₀₀₀ was 2.6. Moreover, when the non-chargeable resin particle dispersion containing the chargeable colored resin particles was prepared by the above-described method using the obtained silicone oil dispersion, and the memory property of the image was evaluated by the above-mentioned method, Δa was It was 4.2% and the image memory property was good.

Example 5
As a macromonomer having a hydrocarbon skeleton, instead of 2.0 parts by weight of UC-102, a terminal acrylated hydrogenated polybutadiene (manufactured by Osaka Organic Chemical Industry Co., Ltd., trade name “SPBDA-S”, number average molecular weight 6000, hereinafter “SPBDA Resin particles were obtained in the same manner as in Example 1 except that 2.0 parts by weight (abbreviated as “-S”) was used. Further, a silicone oil dispersion of resin particles was obtained in the same manner as in Example 1 except that the resin particles were used.

  The obtained resin particles were observed as white particles in the silicone oil dispersion and could be used as white particles for electrophoretic display devices. Moreover, the average particle diameter of the resin particles in the obtained silicone oil dispersion was 321 nm.

Further, the charge amount of the resin particles in the obtained silicone oil dispersion was 0.40 nC / cm ² , and thus the obtained resin particles were non-chargeable resin particles. Further, the sedimentation rate of the non-chargeable resin particles in the obtained silicone oil dispersion was as low as 0.51 μm / s, and the obtained non-charged resin particles were non-charged resin particles having excellent dispersion stability. It was.

The obtained silicone oil dispersion had a viscosity η _{10 at} a shear rate of 10 s ⁻¹ of 10.2 cP, a viscosity η ₁₀₀₀ at a shear rate of _{1000 s} ⁻¹ of 7.5 cP, and a shear rate of The ratio η ₁₀ / η ₁₀₀₀ was 1.4. Moreover, when the non-chargeable resin particle dispersion containing the chargeable colored resin particles was prepared by the above-described method using the obtained silicone oil dispersion, and the memory property of the image was evaluated by the above-mentioned method, Δa was It was 6.3%, and the memory property of the image was good.

[Comparative Example 1]
Resin particles were obtained in the same manner as in Example 1 except that UC-102 was not used and the amount of FM-0721 was changed from 18.0 parts by weight to 20.0 parts by weight. Further, a silicone oil dispersion of resin particles was obtained in the same manner as in Example 1 except that the resin particles were used.

  The obtained resin particles were observed as white particles in the silicone oil dispersion. Moreover, the average particle diameter of the resin particles in the obtained silicone oil dispersion was 314 nm.

Further, the charge amount of the resin particles in the obtained silicone oil dispersion was 0.21 nC / cm ² , and thus the obtained resin particles were non-chargeable resin particles. Moreover, the sedimentation rate of the non-chargeable resin particles in the obtained silicone oil dispersion was as high as 0.81 μm / s, and the non-chargeable resin particles had poor dispersion stability.

The obtained silicone oil dispersion had a viscosity η _{10 at} a shear rate of 10 s ⁻¹ of 6.7 cP, a viscosity η ₁₀₀₀ at a shear rate of _{1000 s} ⁻¹ of 6.1 cP, and the shear rate of The ratio η ₁₀ / η ₁₀₀₀ was as small as 1.1. Moreover, when the non-chargeable resin particle dispersion containing the chargeable colored resin particles was prepared by the above-described method using the obtained silicone oil dispersion, and the memory property of the image was evaluated by the above-mentioned method, Δa was It was 9.9% and the memory property of the image was poor.

[Comparative Example 2]
The amount of dilauroyl peroxide was changed from 2.5 parts by weight to 1.7 parts by weight, the amount of UC-102 was changed from 2.0 parts by weight to 20.0 parts by weight, and the amount of FM-0721 was changed to 18 parts by weight. Resin particles were obtained in the same manner as in Example 1 except that the amount was changed from 0.0 parts by weight to 6.7 parts by weight. Further, a silicone oil dispersion of resin particles was obtained in the same manner as in Example 1 except that the resin particles were used.

  The obtained resin particles were observed as white particles in the silicone oil dispersion. Moreover, the average particle diameter of the resin particles in the obtained silicone oil dispersion was 211 nm. However, evaluation was not possible because the particles aggregated after completion of the cleaning.

  Table 1 summarizes the types and amounts of raw materials used and the evaluation results of the obtained non-chargeable resin particles in Examples 1 to 5 and Comparative Examples 1 and 2.

As described above, in the resin particles of Examples 1 to 5 in which the charge amount is 5 nC / cm ² or less and the viscosity ratio η ₁₀ / η ₁₀₀₀ is in the range of 1.2 to ₁₀ , the charge amount is 5 nC / cm ^2. It can be seen that the dispersion stability in nonpolar solvents and the memory performance of images can be improved as compared with the resin particles of Comparative Example 1 having a viscosity ratio η ₁₀ / η ₁₀₀₀ of less than 1.2 and having a viscosity of cm ² or less. It was. From the comparison between Examples 1 and 4 and Comparative Example 2, when the resin particles are formed by copolymerizing a macromonomer having a hydrocarbon skeleton, a silicone macromonomer, and another vinyl monomer, the particles In order to avoid agglomeration, it has been found that the amount of the macromonomer having a hydrocarbon skeleton is preferably a predetermined amount or less (15 parts by weight or less with respect to 100 parts by weight of another vinyl monomer).

Claims (6)

In a state where the kinematic viscosity is dispersed in a silicone oil having a solid content of 30% by weight in a silicone oil having a viscosity of 100 cSt or less, the distance between the pair of parallel indium tin oxide electrodes with a distance of 50 μm is 15 V. Non-chargeable resin particles obtained by polymerizing a vinyl-based monomer that exhibits a measured charge amount of 5 nC / cm ² or less when a voltage is applied for 60 seconds,
The viscosity at 25 ° C. at a shear rate of 10 s ⁻¹ and 1000 s ⁻¹ of the non-charged resin particle dispersion in which the non-charged resin particles are dispersed in a non-polar solvent at a solid content concentration of 30% by weight is η ₁₀ and When η ₁₀₀₀ ,
1.2 ≦ η ₁₀ / η ₁₀₀₀ ≦ 10
A non-chargeable resin particle characterized by satisfying: The vinyl monomer is a macromonomer having at least one hydrocarbon skeleton selected from the group consisting of a polybutadiene skeleton, a polyisoprene skeleton, and a polyisobutylene skeleton, a silicone macromonomer, and other macromonomers. Vinyl monomers and
0.1 to 15 weight of macromonomer having at least one hydrocarbon skeleton selected from the group consisting of the polybutadiene skeleton, polyisoprene skeleton, and polyisobutylene skeleton with respect to 100 parts by weight of the other vinyl monomer. The non-chargeable resin particles according to claim 1, further comprising 0.1 to 200 parts by weight of the silicone macromonomer.   3. The non-chargeable resin particle according to claim 2, wherein the other vinyl monomer is an aromatic vinyl monomer having no polar group.   The non-chargeable resin particles according to any one of claims 1 to 3, wherein an average particle diameter is in a range of 50 to 1000 nm.   A non-chargeable resin particle dispersion comprising a non-polar solvent and the non-chargeable resin particles according to any one of claims 1 to 4 dispersed in the non-polar solvent. The non-chargeable resin particle dispersion according to claim 5,
The electrophoretic display device, wherein the non-chargeable resin particle dispersion further includes chargeable colored resin particles having a color tone different from that of the non-chargeable resin particles dispersed in the non-polar solvent.

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