JP5827089B2 - Non-charged colored resin particle, non-charged colored resin particle dispersion, and method for producing electrophoretic display device - Google Patents

Description

The present invention is a non-chargeable colored resin particles, relates to the production how uncharged colored resin particle dispersion and an electrophoretic display device. More specifically, the present invention relates to a method for producing non-charged colored resin particles that stably exhibit non-charge properties, non-charged colored resin particles obtained thereby, and non-charged colored resin particle dispersions obtained using the same The present invention relates to a liquid and an electrophoretic display device (image display device) manufacturing method .

An image display device using electrophoresis of colored particles exhibiting chargeability has a wide viewing angle, low power consumption, a memory property that display information does not disappear even when the power is turned off, and low cost. In recent years, it has attracted attention and is expected to spread.
As this image display device, for example, a microcapsule in which charged colored particles showing electrophoretic properties (hereinafter also referred to as “colored electrophoretic particles”) are dispersed in a dispersion medium colored by dissolving a dye or the like is used. A technique for multicolor display has been proposed (see, for example, Japanese Patent No. 2551783: Patent Document 1). However, in Patent Document 1, general pigment particles are used as the colored migrating particles, and there is a problem in that a dispersion medium having a different color tone enters a gap between the particles and color mixing occurs, and a desired color display cannot be performed. .

  In order to solve such problems, a display liquid in which colored resin particles exhibiting charging properties are dispersed in a dispersion medium is sandwiched between two electrode substrates that are arranged to face each other through a spacer and transparent. Panels have been proposed as image display devices. For example, colored electrophoretic particles and non-charged colored particles that are not substantially charged and do not move through the dispersion medium in response to an electric field (also referred to as “colored non-electrophoretic particles”). In other words, a technology is proposed in which a base color corresponding to paper is displayed on colored non-electrophoretic particles, and an image color corresponding to characters or pictures drawn on paper is displayed on colored electrophoretic particles. (For example, refer to JP 2010-210856 A: Patent Document 2).

  However, in the technique using the high refractive resin particles obtained by the method described in the example of Patent Document 2 as the colored non-electrophoretic particles, the colored electrophoretic particles are moved onto the electrode substrate opposite to the display surface, and the colored non-electrophoretic particles are moved. When trying to display the coloring (base color) by the electrophoretic particles, there is a problem that the color non-electrophoretic particles are not concealed and the color of the colored electrophoretic particles can be seen through the display surface, and a desired color display cannot be performed. In addition, for such problems, when the amount of colored non-electrophoretic particles in the solvent is increased in order to perform a desired color display, the viscosity of the entire dispersion (display liquid) increases, and electrophoresis of the colored electrophoretic particles is prevented. There is a problem that the migration speed of the colored migrating particles is reduced.

On the other hand, a method using white particles in which the surface of titanium oxide as a colorant is uniformly coated with a resin having a large difference in refractive index from the dispersion medium is known as a highly concealed colored particle (for example, special No. 2008-122468 gazette: see Patent Document 3).
However, Patent Document 3 does not describe a specific method for producing colored particles. Further, since titanium oxide is used as a colorant, the charge amount becomes high, and such particles are colored. When used as non-electrophoretic particles, there is a problem that electrophoresis of colored electrophoretic particles is inhibited.

Japanese Patent No. 2551783 JP 2010-210856 A JP 2008-122468 A

  An object of the present invention is to solve the above problems, and to provide a production method for obtaining non-electrophoretic non-charged colored resin particles that have high concealability and do not inhibit electrophoresis of colored electrophoretic particles. To do.

  As a result of intensive studies, the inventors of the present invention have once produced a resin-coated pigment (positively charged colored resin particles) having a silicone chain and a carboxyl group by a submerged drying method, and then the carboxyl group and amino group of the resin-coated pigment. By surprisingly finding that by reacting with the amino group of the contained compound, non-charged colored resin particles having a low charge amount and stable non-chargeability and dispersibility can be easily obtained. It came.

Thus, according to the present invention, a segment comprising a silicone chain having an affinity for a nonpolar solvent and a segment comprising an acrylic polymer having an affinity for a nonaqueous polar solvent, and having a carboxyl group and an acid value There was 1~200mgKOH / g, and polyol in a non-polar solvent is insoluble, a pigment, a polyfunctional isocyanate, prior Symbol obtaining a mixed liquid a containing a non-aqueous polar solvent, before Symbol mixture a before Symbol obtaining a mixed solution B by mixing the non-polar solvent, before Symbol mixture to obtain a mixed liquid C to remove the previous SL nonaqueous polar solvent from step B, in the previous SL mixture C, before serial polyol is coating the surface of the pre-Symbol pigment by pre Symbol crosslinked resin obtained by crosslinking with polyfunctional isocyanates and obtaining a mixture D containing resin-coated pigment, adding an amino group-containing compounds prior Symbol mixture D and, before The resin-coated pigment of the crosslinked resin and the amino group-containing compound, the carboxyl group to 1 mole derived from the polyol, 0.2 to 1.5 by mole reacting an amino group of the amino group-containing compound in a non There is provided a method for producing non-chargeable colored resin particles, comprising a step of obtaining chargeable colored resin particles.

Also, according to the present invention, the non- charged colored resin particles are dispersed in the non-polar solvent at a solid content concentration of 10% by weight, and between the ITO electrodes forming parallel flat plates with an inter-electrode distance of 50 μm. And a method for producing the above non-chargeable colored resin particles , which exhibits a charge amount of 10 nC / cm ² or less when a voltage of 10 V is applied for 60 seconds.

Furthermore, according to the present invention, there is provided a method for producing a non-charged colored resin particle dispersion in which the non-charged colored resin particles are dispersed in a non-polar solvent.
Moreover, according to this invention, the manufacturing method of an electrophoretic display device using the said non-chargeable colored resin particle dispersion is provided.

ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the non-electrophoretic non-chargeable colored resin particle which has high concealability and does not inhibit the electrophoresis of colored electrophoretic particles can be provided.
Since the non-charged colored resin particles obtained by the production method of the present invention have stable non-chargeability and dispersibility, the non-charged colored resin particles according to the present invention are used as colored non-electrophoretic particles and combined with the colored electrophoretic particles. When used in an electrophoretic display device, desired color display can be realized without hindering movement of colored electrophoretic particles.

  Moreover, when the amino group-containing compound is an aliphatic amine or an amino group-containing silicone compound, the amino group in the amino group-containing compound is 0.2 to 1.5 with respect to 1 mol of the carboxyl group derived from the polyol. By making the molar reaction, non-charged colored resin particles having more stable non-chargeability and dispersibility can be easily obtained.

Furthermore, when the non-aqueous polar solvent has a boiling point lower than the boiling point of the non-polar solvent and 50 to 200 ° C., the non-polar solvent is silicone oil or paraffinic hydrocarbon, so that the non-aqueous polar solvent is an ester or By using ketones, it is possible to easily obtain non-charged colored resin particles having more stable non-chargeability and dispersibility.
Further, when the polyol is an AB type block copolymer or a graft copolymer, non-charged colored resin particles having more stable non-chargeability and dispersibility can be easily obtained.

The electrophoretic display device using the non-charged colored resin particle dispersion obtained by dispersing the non-charged colored resin particles of the present invention in a non-polar solvent can prevent an undesired color from being displayed.
For example, a non-charged colored resin particle dispersion using the non-charged colored resin particles of the present invention is mixed with a non-charged colored resin particle of the present invention as a colored non-migrated particle in a non-polar solvent. It is formed by dispersing known chargeable colored resin particles as particles.

It is the schematic of the jig for evaluating the charge amount of the colored resin particle obtained in the Example and comparative example of this invention.

The method for producing the non-charged colored resin particles of the present invention (hereinafter also referred to as “non-charged particles”)
A segment comprising a silicone chain having affinity for a nonpolar solvent and a segment comprising an acrylic polymer having affinity for a non-aqueous polar solvent, and having a carboxyl group and an acid value of 1 to 200 mgKOH / g , A step of obtaining a mixed solution A containing a polyol insoluble in a nonpolar solvent, a pigment, a polyfunctional isocyanate, and a nonaqueous polar solvent, and mixing the mixed solution A with a nonpolar solvent to obtain a mixed solution B. Obtaining step (hereinafter also referred to as “dispersing step”);
Removing the non-aqueous polar solvent from the mixed solution B to obtain a mixed solution C (hereinafter also referred to as “removing step”);
In the mixed solution C, a step of obtaining a mixed solution D containing a resin-coated pigment by coating the surface of the pigment with a crosslinked resin obtained by crosslinking a polyol with a polyfunctional isocyanate (hereinafter also referred to as “crosslinking step”);
A step of adding an amino group-containing compound to the mixed solution D and reacting the crosslinked resin of the resin-coated pigment with the amino group-containing compound to obtain non-chargeable colored resin particles (hereinafter also referred to as “reaction step”).
And have.

In the present invention, “non-chargeable” means that neither positive nor negative reaction is shown in the evaluation of polarity (chargeability) and the above-mentioned charge amount is provided. The method for evaluating the polarity (chargeability) and the method for measuring the charge amount will be described in Examples.
Hereinafter, (A) a method for producing non-charged colored resin particles, (B) non-charged colored resin particles, (C) a non-charged colored resin particle dispersion, and (D) an electrophoretic display device will be specifically described. .

(A) Method for Producing Uncharged Colored Resin Particles In the present invention, a resin-coated pigment having a silicone chain and a carboxyl group (positively charged colored resin particles) is once produced by a submerged drying method, and then the carboxyl of the resin-coated pigment. By reacting the group with the amino group of the amino group-containing compound, uncharged colored resin particles can be obtained.
Hereinafter, although this manufacturing method is demonstrated concretely for every process, these are one Embodiment, This invention is not limited by these.

(A-1) Dispersion step First, a segment comprising a silicone chain having an affinity for a nonpolar solvent and a segment comprising an acrylic polymer having an affinity for a nonaqueous polar solvent, and having a carboxyl group and an acid A mixed liquid A containing a polyol having a value of 1 to 200 mg KOH / g and insoluble in a nonpolar solvent, a pigment, a polyfunctional isocyanate, and the nonaqueous polar solvent, and a nonpolar solvent are mixed and mixed. Liquid B is obtained.
In the mixed solution A, polyol and the like are dissolved in a non-aqueous polar solvent, and a pigment and the like are dispersed in the non-aqueous polar solvent.
The mixed solution B is in a state in which a non-aqueous polar solvent in which a polyol or the like is dissolved and a non-soluble component such as a pigment in the non-aqueous polar solvent are dispersed.

(Polyol)
The polyol has a carboxyl group and an acid value of 1 to 200 mgKOH / g.
The carboxyl group possessed by the polyol may be derived from, for example, a vinyl monomer described later.
The amount of the carboxyl group in the polyol can be determined using the acid value as an index, and the measurement method will be described in Examples.
When the acid value of the polyol is less than 1 mgKOH / g, the reaction with the amino group of the amino group-containing compound described later becomes insufficient, the charge amount is low, and the non-chargeable coloring has stable non-chargeability and dispersibility. Resin particles cannot be obtained. When the acid value of the polyol exceeds 200 mgKOH / g, the amount of carboxyl groups present on the particle surface increases, so that dispersibility in a nonpolar solvent deteriorates. The preferable lower limit of the acid value of the polyol is 5 mgKOH / g, the preferable upper limit is 180 mgKOH / g, the more preferable lower limit is 10 mgKOH / g, and the more preferable upper limit is 150 mgKOH / g.

  The polyol is insoluble in a nonpolar solvent. Here, as to whether the polyol is soluble or insoluble in a nonpolar solvent, for example, the polyol is added to silicone and stirred with a stirrer such as a homomixer at room temperature (25 ° C.) to become transparent. It can be easily judged by whether or not.

  Furthermore, the polyol includes a segment composed of a silicone chain having affinity for a nonpolar solvent and a segment composed of an acrylic polymer having affinity for a nonaqueous polar solvent. These two segments have a function of stably dispersing the pigment in a nonpolar solvent. Specifically, this function is because the polyol is present at the interface between the pigment and the nonpolar solvent, the segment having affinity for the nonaqueous polar solvent is on the pigment side, and the segment having affinity for the nonpolar solvent is nonpolar. It is estimated that it is expressed by being located on the solvent side.

  Examples of the segment having affinity for the nonpolar solvent include a segment composed of a silicone chain containing a polyorganosiloxane group. Examples of the segment that is insoluble in the nonpolar solvent and has an affinity for the nonaqueous polar solvent include a segment composed of an acrylic chain not containing a polyorganosiloxane group.

Examples of the segment composed of the silicone chain include dimethyl silicone represented by the following general formula (1) and a modified silicone segment into which an organic group is introduced.

In the general formula (1), R represents a hydrogen atom, an alkyl group such as a methyl group or an ethyl group, or a phenyl group, an amino group, an aralkyl group, an amino group, an epoxy group, a polyether group, or an alkyl polyether group. . M and n are integers of 0 or more.

  In addition, the segment made of an acrylic chain not containing the polyorganosiloxane group is not particularly limited. For example, acrylic acid esters (methyl acrylate, methyl acrylate, ethyl acrylate, 2-ethylhexyl acrylate, acrylic acid) 2-hydroxyethyl) and methacrylic acid esters (methyl methacrylate, ethyl methacrylate, butyl methacrylate, 2-hydroxyethyl methacrylate, etc.) are preferably used. .

  Further, examples of vinyl monomers that can be used in combination with the above monomers include styrene derivatives (styrene, p-hydroxymethylstyrene, p-methoxystyrene, etc.), vinyl ethers (methyl vinyl ether, ethyl vinyl ether, cyclohexyl vinyl ether, hydroxyethyl vinyl ether, hydroxybutyl). Vinyl ethers), unsaturated carboxylic acids (acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid, etc.), acrylamides (N, N-dimethylacrylamide, N-tert-butylacrylamide, N-cyclohexylacrylamide, etc.), Examples include methacrylamides (N, N-dimethylmethacrylamide) and acrylonitrile.

In the present invention, the polyol includes, for example, a polysiloxane group-containing graft copolymer described in JP-A-1-254719 and JP-A-63-291925, wherein a polysiloxane group is bonded to an acrylic polymer. An AB type block copolymer comprising a polymer part (hereinafter referred to as polymer part A) and an acrylic polymer part (hereinafter referred to as polymer part B) can be suitably used. A polysiloxane group-containing graft copolymer in which a polysiloxane group is bonded to an acrylic polymer can also be suitably used.
In particular, the weight ratio A / B between the polymer part A and the polymer part B is 25/75 to 90/10, and the weight average molecular weight in terms of polystyrene measured by gel permeation chromatography using tetrahydrofuran as an eluent. Is suitable for obtaining the non-chargeable colored resin particles of the present invention. Examples of such a copolymer include a product name Modiper FS700 (molecular weight Mw = 27000, hydroxyl value 60 mgKOH / g) manufactured by NOF Corporation.

The polyol has a radical polymerizable group at one end of a silicone polymer such as polydimethylsiloxane described in JP-A-60-123518 and JP-A-63-227670. A silicone-based graft copolymer obtained by copolymerizing a silicone-based macromonomer with another polymerizable monomer can also be suitably used.
As such a graft copolymer type polyol, for example, trade name Rezata GS1015 (molecular weight Mw = 23000, hydroxyl value 120 mgKOH / g, acid value 14 mgKOH / g, solid content 45% by weight, manufactured by Toa Gosei Co., Ltd. Ether acetate solution) and the like.

  Furthermore, a segment having an acrylic chain not containing a polyorganosiloxane group and having an affinity for a non-aqueous polar solvent, and a segment having a silicone chain containing a polyorganosiloxane group and having an affinity for the non-polar solvent. Examples of the copolymer provided include silicone macroazo initiation as described in JP-A-6-93100, JP-A-11-189621, JP-A-11-228631, and JP-A-2000-313709. A polymer obtained by introducing a polysiloxane block copolymer component by polymerizing a vinyl monomer using a molecular weight adjusting agent such as an agent and lauryl mercaptan can be suitably used.

Examples of the silicone macroazo initiator include an initiator having a structure in which a plurality of polydimethylsiloxane segments represented by the following formula (2) are connected via an azo group.

In this initiator, in formula (2), R ¹ , R ² , R ³ and R ⁴ are each independently a hydrogen atom, a lower alkyl group or a cyano group, and R ⁵ , R ⁶ , R ⁷ and R ⁸ is independently a hydrogen atom or a lower alkyl group, R ⁹ and R ¹⁰ are each independently a hydrogen atom, an alkyl group, a haloalkyl group, or a phenyl group, and p and q are each independently 1 to 6 M and n are each independently an integer of 0 to 6, and r is an integer of 0 to 200.
For example, the block-type copolymer can be obtained by reacting a polymer azo initiator and a vinyl monomer with a polymerization temperature of 70 ° C. for 5 hours using toluene as a solvent so that the target polydimethylsiloxane and vinyl polymer are linear. A block copolymer bonded to can be obtained.
Examples of commercially available products include polymer azo initiators (trade names VPS-0501 and VPS-1001) manufactured by Wako Pure Chemical Industries, Ltd.

  The vinyl monomers that can be used here are mainly acrylic esters (methyl acrylate, methyl acrylate, ethyl acrylate, 2-ethylhexyl acrylate), methacrylic esters (methyl methacrylate, ethyl methacrylate). , Butyl methacrylate, 2-ethylexyl methacrylate, etc.). These vinyl monomers may be used in combination with other monomers. Other monomers include styrene derivatives (styrene, p-hydroxymethyl styrene, p-methoxy styrene, etc.), vinyl ethers (methyl vinyl ether, ethyl vinyl ether, cyclohexyl vinyl ether, hydroxyethyl vinyl ether, hydroxybutyl vinyl ether, etc.), unsaturated carboxylic acids (Acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid, etc.), acrylamides (N, N-dimethylacrylamide, N-tert-butylacrylamide, N-cyclohexylacrylamide, etc.), methacrylamides (N, N- Dimethylmethacrylamide), acrylonitrile and the like.

In particular, in the present invention, in order to obtain an AB type block copolymer suitable for the production of the desired non-chargeable colored resin particles, the ratio of the polymeric azo initiator to the vinyl monomer is 1: 1 to 1. : 4 is preferable, and 1: 2 to 1: 3 is more preferable. The weight average molecular weight of the block copolymer is preferably in the range of 20000 to 150,000.
In the present invention, a hydroxyl group is contained in the block copolymer or graft copolymer to form a polyol. To prepare a polyol, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, acrylic acid Vinyl monomers having a hydroxyl group such as hydroxybutyl, hydroxybutyl methacrylate, polyalkylene glycol monoacrylate, and polyalkylene glycol monomethacrylate can be used. The amount of the vinyl monomer having a hydroxyl group is 1 to 50 weights when the total of materials such as all monomers and polymer azo initiator constituting the block copolymer or graft copolymer is 100 parts by weight. Parts, preferably 2 to 30 parts by weight.

(Pigment)
The pigment is not particularly limited, and an organic pigment or an inorganic pigment can be used.
Specifically, for example, C.I. I. Pigment yellow 1, C.I. I. Monoazo pigments such as CI Pigment Yellow 74; I. Pigment yellow 12, C.I. I. Disazo pigments such as CI Pigment Yellow 17; I. Non-benzidine azo pigments such as CI Pigment Yellow 180; I. Azo lake pigments such as C.I. Pigment Yellow 100, C.I. I. Condensed azo pigments such as C.I. Pigment Yellow 95, C.I. I. Pigment Yellow 115, acidic dye lake pigments, C.I. I. Pigment yellow 18 and other basic dye lake pigments, anthraquinone pigments such as flavantron yellow, isoindolinone yellow 3RLT, C.I. I. Pigment Yellow 139 and other isoindolinone pigments, quinophthalone yellow and other quinophthalone pigments, isoindoline yellow and other isoindoline pigments, C.I. I. Nitroso pigments such as C.I. Pigment Yellow 153, C.I. I. Metal complex azomethine pigments such as C.I. Pigment Yellow 117; I. Monoazo pigments such as C.I. Pigment Red 3; I. Disazo pigments such as CI Pigment Red 38; I. Pigment Red 53: 1 and C.I. I. Azo lake pigments such as CI Pigment Red 57: 1; I. Condensed azo pigments such as C.I. Pigment Red 144; I. Acidic dye lake pigments such as C.I. Pigment Red 174; I. Basic dye lake pigments such as C.I. Pigment Red 81; I. Anthraquinone pigments such as CI Pigment Red 177; I. Thioindigo pigments such as CI Pigment Red 88; I. Perinone pigments such as C.I. Pigment Red 194; I. Perylene pigments such as CI Pigment Red 149; I. Quinacridone pigments such as C.I. Pigment Red 122; I. Isoindolinone pigments such as CI Pigment Red 180; I. Alizarin lake pigments such as CI Pigment Red 83; I. Disazo pigments such as C.I. Pigment Blue 25, C.I. I. Phthalocyanine pigments such as C.I. Pigment Blue 15; I. Acidic dye lake pigments such as C.I. Pigment Blue 24; I. Basic dye lake pigments such as CI Pigment Blue 1; I. Anthraquinone pigments such as C.I. Pigment Blue 60; I. Pigment Blue 18 and other alkali blue pigments, aniline black pigments and other organic pigments, copper oxides, iron oxides (CI Pigment Black 11), titanium oxides such as titanium dioxide and titanium black, and furnaces And carbon black pigments such as black, lamp black, acetylene black, and channel black.

  Furthermore, pigments dispersed in advance with a water-insoluble resin, so-called processed pigments, can also be used. Specifically, what is called a color chip (Taihei Chemical Co., Ltd., manufactured by Taisei Kako Co., Ltd.) obtained by kneading a pigment and a resin under heating with two rolls or the like, or a commercially available processed pigment such as Microlith (manufactured by BASF) can be used. Specifically, processed pigments typified by microlith pigments such as microlith-A, -K, and -T can be suitably used. Specific examples thereof include Microlith Yellow 4G-A, Micro Resled BK, Microlith Magenta 5B-K, Microlith Blue 4G-K, Microlith White RK, Microlith Blue 4G-T, and Microlith. Black CT etc. are mentioned.

In addition, as the water-insoluble resin for dispersing the pigment used in the processed pigment, vinyl chloride-vinyl acetate copolymer, acrylic resin, butyral resin, olefin resin, polyester resin, and the like can be used.
For example, since the colored resin particles used for electronic paper preferably have an average particle size of 20 nm to 10 μm, the pigment preferably has an average particle size of 10 nm to 1 μm. The shape of the pigment is not particularly limited, but it is preferably as close to a sphere as possible in consideration of dispersion stability in the dispersion medium.

The pigment may be previously contacted with a polyol in order to improve dispersibility in a non-aqueous polar solvent. In addition to the polyol, for example, it may be brought into contact with an acrylic resin, vinyl chloride-vinyl acetate copolymer, butyral resin, olefin resin, polyester resin, or the like.
The pigment may be surface-treated with a pigment dispersant. This surface treatment is preferably performed in a non-aqueous polar solvent before the pigment is dispersed in the non-polar solvent.
Examples of pigment dispersants, for example, polymer dispersant type pigment dispersants include Solsperse series (manufactured by Nihon Lubrizol), Disperbyk series and BYK series (manufactured by Big Chemie), Ajisper (manufactured by Ajinomoto Fine Techno Co.), florene Series (manufactured by Kyoeisha Chemical Co., Ltd.), Disparon series (manufactured by Enomoto Kasei Co., Ltd.), etc. can be used as commercial products without any special purification. These polymer activator type pigment dispersants have a salt, ester group, amino group, etc. in the molecule, have a low solution viscosity when dissolved in an organic solvent, and have the ability to subdivide the pigment. Have.

Examples of the Sol Sparse series include Sol Sparse 10,000, Sol Sparse 20000, Sol Sparse 24000, Sol Sparse 27000, Sol Sparse 28000, Sol Sparse 32550, Sol Sparse 34750, Sol Sparse 54000, and the like. These Solsperse series are soluble in non-aqueous polar solvents, but difficult to dissolve in silicone oil, so it is estimated that the contribution to the dispersion stability of colored resin particles in silicone oil is low. The
Examples of the Disperbyk series and BYK series include Disperbyk-103, Disperbyk-161, Disperbyk-166, Disperbyk-167, BYK-P104, and BYK-P105.
Examples of the Ajisperse series include PB-881 and PB-821, which have the following general formula (3).

In the above general formula (3), R ¹ is a linear or branched alkyl or alkenyl group having 8 to 22 carbon atoms, m is an integer of 0 to 20, Y is O or COO, j is 0 or 1 An integer, X represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or a substituent represented by the following general formula (4), and A represents a neutral or acidic amino acid residue excluding the amino group moiety.

In the general formula (4), R ² is a linear or branched alkyl group or alkenyl group having 8 to 22 carbon atoms that is the same as or different from R ¹ , n is an integer of 0 to 20, Y is O or COO, k represents 0 or 1.
Examples of the florene series include KDG-2400. Examples of the disparon series include disparon 1210 and disparon 1220.

  Moreover, coupling agents, such as a silane coupling agent, an aluminum coupling agent, a titanate coupling agent, a zirconium coupling agent, can also be used as a pigment dispersant.

  Examples of the silane coupling agent include 3-aminopropyltriethoxysilane, 3-aminopropylmethyldiethoxysilane, 3-ureidopropyltriethoxysilane, 3-ureidopropyltrimethoxysilane, and 3-aminopropyltrimethoxysilane. 3-aminopropyl-tris (2-methoxy-ethoxy-ethoxy) silane, N-methyl-3-aminopropyltrimethoxysilane, N-aminoethyl-3-aminopropyl-trimethoxysilane, diaminosilane, N-aminoethyl -3-aminopropylmethyldimethoxysilane, triaminopropyl-trimethoxysilane, 3-amino-4,5-dihydroimidazolol propyltriexosilane, 3-methacryloxypropyltrimethoxysilane, 3-glycidoxypropioxy Trimethoxysilane, 3-mercaptopropyltrinitroxysilane, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-chloropropyltriethoxysilane, 3-chloropropyltrimethoxysilane, 3-chloropropylmethyldimethoxy Silane, 3-cyanopropyltriethoxysilane, vinyltrichlorosilane, vinyltriethoxysilane, vinyltrimethoxysilane, vinyltri (2-methoxyethoxy) silane, hexamethyldisilazane, N, N-bis (trimethylsilyl) acetamide, methyltri Methoxysilane, methyltriethoxysilane, ethyltrichlorosilane, n-propyltrimethoxysilane, isobutyltrimethoxysilane, amyltrichlorosilane, octyl Riethoxysilane, vinyltris (β-methoxyethoxy) silane, γ-methacryloxypropyltrimethoxysilane, N-β- (aminoethyl) γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-phenyl- γ-aminopropyltrimethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, methyltri (methacryloyloxyethoxy) silane, methyltri (glycidyloxy) silane, long-chain alkyltriethoxysilane, tetramethylsilicate, tetraethylsilicate, vinyltris (2 -Methoxyethoxy) silane, 3-glycidoxypropylmethyldimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-methacryloxypropyltri Examples include methoxysilane and γ- (2-aminoethyl) aminopropylmethyldimethoxysilane.

Examples of the aluminum coupling agent include acetooctadecyloxyaluminum diisopropionate.
Examples of titanate coupling agents include isopropyl triisostearoyl titanate, isopropyl tristearoyl titanate, isopropyl trioctanoyl titanate, isopropyl dimethacrylisostearoyl titanate, isopropyl tridodecylbenzenesulfonyl titanate, isopropyl isostearoyl diacryl titanate, isopropyl trititanate. (Dioctyl phosphate) titanate, isopropyl tricumyl phenyl titanate, isopropyl tris (dioctyl pyrophosphate) titanate, isopropyl tri (n-aminoethyl-aminoethyl) titanate, tetraisopropyl bis (dioctyl phosphite) titanate, tetraoctyl bis (ditridecyl) Phosphite) Titanate, Tet (2,2-diallyl-1-butyl) bis (
Ditridecyl) phosphite titanate, dicumylphenyloxyacetate titanate, bis (dioctylpyrophosphate) oxyacetate titanate, diisostearoyl ethylene titanate, bis (dioctyl palophosphate) ethylene titanate, bis (dioctyl palophosphate) diisopropyl titanate, tetramethyl ortho Titanate, tetraethyl orthotitanate, tetrapropyl orthotitanate, tetraisopropyl tetraethyl orthotitanate, tetrabutyl orthotitanate, butyl polytitanate, tetraisobutyl orthotitanate, 2-ethylhexyl titanate, stearyl titanate, cresyl titanate monomer, cresyl titanate polymer, di Isopropoxy-bis- (2, -Pentadionate) Titanium (IV), Diisopropyl-bis-triethanolamino titanate, Octylene glycol titanate, Titanium lactate, Acetoacetate cetyl titanate, Diisopropoxybis-8acetylacetonato) Titanium, Di-n-butoxybis (Triethanolaluminate) titanium, dihydroxybis (lactato) titanium, titanium-isopropoxyoctylene glycolate, titra-n-butoxytitanium polymer, tri-n-butoxytitanium monostearate polymer, butyl titanate dimer, titanium acetylacetate , Polytitanium titanium acetylacetonate, titanium octylene glycolate, titanium lactate ammonium salt, titanium lactate ethyl ester, titanium trieta Ruamineto and polyhydroxy titanium stearate and the like.

  Examples of the zirconium-based coupling agent include zirconium butyrate, zirconium acetylacetonate, acetylacetone zirconium butyrate, zirconium lactate, zirconium stearate butyrate, tetra (triethanolamine) zirconate, and tetraisopropylzirconate.

The amount of the polyol used is not particularly limited, but a preferable lower limit is 30 parts by weight and a preferable upper limit is 130 parts by weight with respect to 100 parts by weight of the pigment.
The amount of the pigment dispersant used is not particularly limited, but the preferred lower limit is 3 parts by weight and the preferred upper limit is 30 parts by weight with respect to 100 parts by weight of the pigment.
In addition, in order to finely disperse the pigment to a desired particle size, a dyno mill or DSP is used by using a dispersion medium such as glass beads, steel beads or zirconia beads in the presence of a solvent, a pigment dispersant, and a polyol as necessary. -It is preferable to disperse by a disperser such as a bead mill such as a mill, a roll mill, a sand mill, an attritor, a high pressure spray mill such as a kneader or a nanomizer.

(Polyfunctional isocyanate)
The polyfunctional isocyanate is a compound that forms a crosslinked resin by reacting with the polyol. A polyfunctional means two or more functionalities, and a preferable functional number is 2-6.

As the polyfunctional isocyanate, for example, a compound in which a plurality of isocyanate groups are bonded to a basic structure such as an aliphatic chain hydrocarbon, an alicyclic hydrocarbon, and an aromatic hydrocarbon can be used. Aromatic polyisocyanates such as diphenylmethane diisocyanate (MDI), polymethylene polyphenylene polyisocyanate, polytolylene polyisocyanate, tolylene diisocyanate (TDI), xylylene diisocyanate (XDI), naphthalene diisocyanate (NDI), hexamethylene diisocyanate (HDI) Aliphatic polyisocyanates such as isophorone diisocyanate (IPDI), other carbodiimide-modified polyisocyanates of the above polyisocyanates, isocyanurates It can be mentioned door type polyisocyanate, biuret type polyisocyanate, and adduct type polyisocyanate. Moreover, it is a reaction product obtained by reacting an excess polyisocyanate with a polyol, and a so-called urethane prepolymer having an isocyanate group at a molecular end can be applied, and further, a mixture thereof can also be used.
Specific examples of these include HDI manufactured by Asahi Kasei Chemicals Co., Ltd., trade name: Duranate 50M, and diphenylmethane diisocyanate manufactured by Nippon Polyurethane Co., Ltd., Millionate MT-F.

  Furthermore, as isocyanurate type polyisocyanate made of HDI, manufactured by Asahi Kasei Chemicals Corporation, trade name: Duranate TPA-100 (viscosity: 1400 mPa · s / 25 ° C., NCO%: 23.1%), TLA-100 (viscosity: 500 mPa · s / 25 ° C., NCO%: 23.5%), as a burette type polyisocyanate, manufactured by Asahi Kasei Chemicals Corporation, trade name: Duranate 24A-100 (viscosity: 1800 mPa · s / 25 ° C., NCO%: 23.5) %), As an adduct type polyisocyanate, manufactured by Asahi Kasei Chemicals Corporation, trade name: Duranate P301-75E (containing 25% ethyl acetate, viscosity: 350 mPa · s / 25 ° C., NCO%: 12.5%), from urethane prepolymer As polyisocyanate, manufactured by Asahi Kasei Chemicals Name: Duranate D101 (viscosity: 500 mPa · s / 25 ° C., NCO%: 19.7%) and D102 (viscosity: 1800 mPa · s / 25 ° C., NCO%: 15.8%).

It is preferable to use a polyfunctional isocyanate in the range which becomes 0.3-1.0 mol isocyanate group with respect to 1 mol of hydroxyl groups according to content of the hydroxyl group in the polyol to be used. More specifically, for example, the use amounts of polyol and polyfunctional isocyanate can be generally calculated by the following formula.
Formula: Required amount of polyfunctional isocyanate [parts] =
(Hydroxyl value of polyol / 561) × (42 × 100) /
(NCO% of polyfunctional isocyanate) × (polyol amount / 100) × (NCO / OH ratio)
If it is in this range, it is difficult to peel from the pigment, and colored resin particles having good dispersibility in a nonpolar solvent can be obtained.

A crosslinking catalyst may be present during the reaction of the polyfunctional isocyanate and the polyol. The crosslinking catalyst is not particularly limited, and examples thereof include tertiary amines such as trimethylamine, triethylamine and tributylamine, amine compounds such as dimethylaminopropylamine and N-ethylmorpholine, tin compounds such as dibutyltin dilaurate, and titanium acetylacetonate. Zirconium compounds such as titanium compounds and zirconium acetylacetonate can be suitably used.
The amount of the crosslinking catalyst used is not particularly limited, but the preferred lower limit is 0.01 parts by weight, the preferred upper limit is 5 parts by weight, and the more preferred lower limit is 0.05 parts by weight with respect to 100 parts by weight of the polyfunctional isocyanate. A more preferred upper limit is 3 parts by weight.

(Non-aqueous polar solvent)
The non-aqueous polar solvent means a polar solvent that substantially does not contain water, and more specifically, is not particularly limited as long as it is a solvent that can dissolve the polyol and the polyfunctional isocyanate. For example, methyl formate, Esters such as ethyl formate, propyl formate, butyl formate, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, methyl propionate, ethyl propionate, methyl butyrate, ethyl butyrate, acetone, methyl ethyl ketone, diethyl ketone, methyl isobutyl ketone, And ketones such as cyclohexanone.

The boiling point of the non-aqueous polar solvent is preferably less than the boiling point of the non-polar solvent. Moreover, it is preferable that the boiling point of the said non-aqueous polar solvent is 50-200 degreeC. By having a boiling point in this range, the mixed liquid can be easily dispersed in the nonpolar solvent in the dispersion step, and the nonaqueous polar solvent can be removed in the removal step in a short time. A more preferable range of the boiling point of the non-aqueous polar solvent is 50 to 150 ° C.
In particular, the boiling point of the non-aqueous polar solvent is more preferably 50 to 120 ° C. from the viewpoint of ease of production of the dispersion.
The boiling point of the non-aqueous polar solvent is preferably 10 ° C. or more lower than the boiling point of the non-polar solvent, more preferably 20 ° C. or more, and further preferably 30 ° C. or more. When the difference in boiling points is less than 10 ° C., when removing the non-aqueous polar solvent, the non-polar solvent may also be removed at the same time, which may reduce the dispersion stability.

(Nonpolar solvent)
The nonpolar solvent (nonpolar solvent) is not particularly limited as long as it is an insoluble solvent with respect to the polyol, but is preferably a material having low volatility and high safety as a chemical substance. Examples thereof include paraffinic hydrocarbons, silicone oils, and fluorine-based liquids that are boiling components.
Examples of the paraffinic hydrocarbons include normal paraffinic hydrocarbons and isoparaffinic hydrocarbons having 20 or more carbon atoms (boiling point of 80 ° C. or higher). For reasons of safety and volatility, use isoparaffins. Is preferred. Specifically, trade names: Isopar H (100% distillation temperature 188 ° C.), Isopar L (100% distillation temperature 199 ° C.), Isopar G (100% distillation temperature 176 ° C.), Isopar M, manufactured by Exxon (100% distillation temperature 199 ° C.), Idemitsu Petrochemical Co., Ltd., trade names: IP solvent 1620 (100% distillation temperature 202 ° C.), IP solvent 2028 (100% distillation temperature 262 ° C.), IP solvent 2835 ( 100% outflow temperature 353 ° C.). Here, the 100% distillation temperature means a temperature at the end of distillation obtained by a distillation test under normal pressure.

  Specific examples of the silicone oil include silicone oils in which a hydrocarbon group is bonded to a siloxane bond (eg, dimethyl silicone oil, diethyl silicone oil, methyl ethyl silicone oil, methyl phenyl silicone oil, diphenyl silicone oil, etc.), modified Silicone oil (for example, fluorine-modified silicone oil, amine-modified silicone oil, carboxyl-modified silicone oil, epoxy-modified silicone oil, alcohol-modified silicone oil, etc.) can be mentioned. Among these, dimethyl silicone is particularly preferable from the viewpoints of high safety, chemical stability, good long-term reliability, and high resistivity.

(Use amount of polyol, polyfunctional isocyanate, pigment and non-aqueous polar solvent)
The amount of the non-aqueous polar solvent used is an amount that can dissolve the polyol and polyfunctional isocyanate and disperse the pigment, but is preferably as small as possible in order to shorten the time for subsequent removal. From such a point of view, the amount of the non-aqueous polar solvent used is preferably 200 parts by weight, preferably 3000 parts by weight, more preferably the lower limit with respect to 100 parts by weight of the polyol, the polyfunctional isocyanate, and the pigment. 300 parts by weight, and a more preferable upper limit is 1500 parts by weight.

  When the non-charged colored resin particle dispersion using the non-charged colored resin particles of the present invention is used in, for example, a display device, a better display can be obtained when the amount of pigment is as large as possible. However, when the amount of the crosslinked resin is decreased, the dispersion stability of the pigment in the dispersion may be lowered. From such a viewpoint, the amount of the pigment used is preferably 5 parts by weight, preferably 100 parts by weight, more preferably 20 parts by weight, and more preferably 80 parts by weight with respect to 100 parts by weight of the crosslinked resin. Part. Note that the amount of the crosslinked resin composed of the polyol-derived component and the polyfunctional isocyanate-derived component is substantially equivalent to the total amount of the polyol and the polyfunctional isocyanate.

(Mixing / dispersing in non-aqueous polar solvent: Preparation of mixture A)
The production method of the mixed liquid A is not particularly limited, and for example, a media type dispersion device such as a ball mill, an attritor, or a sand mill, a shear type dispersion device such as a homomixer, a homogenizer, or a biomixer, an ultrasonic dispersion device, or the like was used. A method is mentioned. Among these, a method using an ultrasonic dispersion apparatus with high dispersion efficiency is preferable.
Dispersion by irradiating with ultrasonic waves is achieved by immersing a container containing a mixture of polyol, polyfunctional isocyanate, pigment, and non-aqueous polar solvent in a generally used ultrasonic cleaning device filled with an appropriate amount of medium such as warm water. It can be carried out by a method of irradiating a sound wave or a method of irradiating an ultrasonic wave by inserting an ultrasonic vibrator into a container containing a mixed solution using an internal irradiation type ultrasonic generator.

The ultrasonic transmission frequency is preferably 16 kHz or more, and more preferably in the range of 20 to 500 kHz. The output is preferably 10 to 1000 W per 1 L of the medium irradiated with ultrasonic waves.
For dispersion under ultrasonic irradiation, a mechanical stirrer such as a magnetic stirrer can be used in combination. Furthermore, you may adjust temperature by circulating the solvent which controlled temperature with the external temperature control apparatus in an ultrasonic cleaning apparatus. In addition, it does not specifically limit as dispersion temperature, It can carry out at room temperature (about 25 degreeC), and can cool or heat as needed.
The order of adding the polyol, polyfunctional isocyanate and pigment to the non-aqueous polar solvent is not particularly limited. Therefore, after adding the polyol and the polyfunctional isocyanate, the pigment may be added, the three may be added in the reverse order, or the three may be added simultaneously.
That is, as in the examples, a pigment dispersion in which a pigment is dispersed in a non-aqueous polar solvent and a solution in which a polyol is dissolved in a non-aqueous polar solvent are prepared in advance, and these are mixed with other components in a non-aqueous polar solvent. May be mixed.

(Preparation of mixture B)
Next, the liquid mixture A and the nonpolar solvent are mixed to obtain a liquid mixture B.
The mixed solution B is in a state where a non-aqueous polar solvent in which a polyol or the like is dissolved and a non-soluble component such as a pigment with respect to the non-aqueous polar solvent is dispersed. Any method of dispersing the pigment in the medium can be used.
Further, in mixing the mixed solution A and the nonpolar solvent, the nonpolar solvent may be added to the mixed solution A, or vice versa. It may be added.

(A-2) Removal Step The production method of the present invention then has a step of obtaining the mixed solution C by removing the non-aqueous polar solvent from the mixed solution B.
In this removal step, for example, the non-aqueous polar solvent can be removed by heating and / or reducing the pressure of the mixed solution B. This removal step may also serve as a crosslinking step in which a polyol is crosslinked with a polyfunctional isocyanate to form a crosslinked resin layer. In addition, when the removal step does not serve as a crosslinking step, the non-aqueous polar solvent is removed to form a layer containing a polyol and a polyfunctional isocyanate on the pigment surface, and then subjected to the crosslinking step to form a crosslinked resin layer. Can be obtained.

  The heating temperature is not particularly limited as long as the non-aqueous polar solvent can be removed. For example, if heating is performed at a temperature 50 to 200 ° C. higher than the boiling point of the non-aqueous polar solvent, the non-aqueous polar solvent can be easily removed. Moreover, you may remove a nonpolar solvent by pressure reduction at the temperature below normal temperature using the difference in boiling point. Furthermore, the removal time can be shortened by reducing the pressure simultaneously with the heating.

The removing step may be performed while stirring the dispersion. As the stirring method, any method of dispersing the pigment in the non-aqueous polar medium in the dispersion step can be used.
The end point of removal of the non-aqueous polar solvent can be determined by measuring with gas chromatography or the like.
Furthermore, when the removal step also serves as a crosslinking step, the heating temperature is preferably a temperature that is 10 ° C. or more higher than the boiling point of the non-aqueous polar solvent, more preferably a temperature that is 20 ° C. or more, more preferably 30 ° C. or more. More preferably, the temperature is high.

(A-3) Crosslinking step Next, in the production method of the present invention, in the mixed solution C, the surface of the pigment is coated with a crosslinked resin obtained by crosslinking a polyol with a polyfunctional isocyanate and the resin-coated pigment is contained. D is obtained.
In the present invention, a crosslinking catalyst such as triethylamine used during the reaction of the polyfunctional isocyanate and the polyol may be added at the time of preparing the dispersion of the polyol, the polyfunctional isocyanate and the pigment as the non-aqueous polar solvent. It may be added to the nonpolar solvent during dispersion in the solvent, or it may be added to the nonpolar solvent after removing the nonaqueous polar solvent by heating and / or depressurizing the system containing the nonpolar solvent and the dispersion. . The addition timing of the crosslinking catalyst can be appropriately selected in consideration of the type of crosslinking catalyst used and the manufacturing process. It is preferable to add a crosslinking catalyst to the nonpolar solvent after heating and / or depressurizing the system containing the nonpolar solvent and the mixed solution to remove the nonaqueous polar solvent.

(A-4) Reaction step Next, in the production method of the present invention, an amino group-containing compound is added to the mixed solution D, and the cross-linked resin of the resin-coated pigment and the amino group-containing compound are reacted to form a non-chargeable colored resin. A step of obtaining particles. More specifically, the non-chargeable colored resin particles are obtained by reacting the carboxyl group derived from the polyol in the crosslinked resin with the amino group of the amino group-containing compound.
The amino group-containing compound is not particularly limited. For example, aliphatic amines such as butylamine, hexylamine, octylamine, stearylamine, dibutylamine and triethylamine; amino group-containing silicones such as bis (3-aminopropyl) polydiphenylsiloxane Compound etc. are mentioned.

It is preferable to react 0.2 to 1.5 mol of the amino group in the amino group-containing compound with respect to 1 mol of the carboxyl group derived from the polyol.
When the amino group is less than 0.2 mol, the charge amount of the obtained non-chargeable colored resin particles may be higher than 10 nC / cm ² . On the other hand, when the amount exceeds 1.5 mol, an effect commensurate with the addition cannot be obtained, and a lot of time is required for washing for removing the excess amino group-containing compound, which may reduce the production efficiency. . The minimum with a preferable amino group is 0.3 mol, and a preferable upper limit is 1.0 mol.

The amount of amide groups is 0.2 to 1.5 molar equivalents, preferably 0.5 to 1.0 molar equivalents relative to the amount of carboxyl groups in the chargeable colored resin particles.
The fact that the reaction product has an amide group can be confirmed by, for example, infrared spectroscopy, and the details thereof will be described in Examples.

  In order to obtain non-chargeable colored resin particles, the method of reacting the resin-coated pigment cross-linked resin with the amino group-containing compound is not particularly limited. For example, the amino group-containing compound is added to the resin-coated pigment dispersion, Examples thereof include a method in which the amino group-containing compound is stirred in a state of being dissolved in a nonpolar solvent under heating, and then centrifugal sedimentation and washing are repeated using the nonpolar solvent.

(B) Uncharged colored resin particles The non-charged colored resin particles of the present invention are obtained by the above production method, and the distance between the electrodes is 50 μm in a state of being dispersed in the nonpolar solvent at a solid content concentration of 10% by weight. When a voltage of 10 V is applied for 60 seconds, the charge amount is 10 nC / cm ² or less.

The non-chargeable colored resin particles of the present invention have improved dispersion stability in the dispersion due to the crosslinked resin layer covering the surface of the pigment.
The coating with the cross-linked resin layer in the present invention means that a pigment is taken into the resin and can be confirmed by a transmission electron microscope (TEM) photograph. For example, at least one or more pigments may be contained in the resin. Moreover, as long as it is inside the resin, the pigment may be unevenly distributed and uniformly dispersed.
The shape of the non-chargeable colored resin particles of the present invention is not particularly limited. However, in the use of the display device, it is preferable that the colored resin particles have a shape as close to a sphere as possible.

  The average particle diameter of the non-chargeable colored resin particles of the present invention is not particularly limited, but the preferred lower limit is 0.1 μm and the preferred upper limit is 1.0 μm. When the average particle size is less than 0.1 μm, the viscosity of the nonpolar solvent increases during polymerization, and as a result, it may not be possible to produce non-charged colored resin particles having a stable average particle size. On the other hand, when it exceeds 1.0 μm, dispersion stability in a nonpolar solvent may be deteriorated. A more preferable lower limit of the average particle diameter is 0.2 μm, and a more preferable upper limit is 0.8 μm.

Although it does not specifically limit as specific gravity of the non-chargeable colored resin particle of this invention, A preferable minimum is 1.0 and a preferable upper limit is 3.0. If the specific gravity is less than 1.0, the pigment concentration becomes low, and color development may be deteriorated. On the other hand, when it exceeds 3.0, the dispersibility in a nonpolar solvent may deteriorate. The more preferable lower limit of the specific gravity is 1.2, and the more preferable upper limit is 2.5.
Further, the obtained non-chargeable colored resin particles may be taken out from the nonpolar solvent, or may be used as it is without being taken out. The extracted resin particles can be washed with a nonpolar solvent as necessary. Further, the washed nonpolar colored resin particles may be dispersed again in the nonpolar solvent.

The non-chargeable colored resin particles of the present invention are excellent in dispersion stability in a non-polar solvent, particularly silicone oil, have a high colorant content, and have stable non-charge properties. Therefore, the non-charged colored resin particle dispersion utilizing such properties can be suitably used as a display element of an electrophoretic display device utilizing electrophoresis such as electronic paper.
Nonpolar solvents include those exemplified in the method for producing (A) non-charged colored resin particles, for example, paraffinic hydrocarbons such as pentane, hexane, heptane, octane, nonane, decane, dodecane; isohexane, isooctane, isododecane. Iso-paraffin hydrocarbons such as liquid paraffins; alkyl naphthenic hydrocarbons such as liquid paraffin; silicone oils such as dimethyl silicone oil, phenylmethyl silicone oil, dialkyl silicone oil, alkylphenyl silicone oil, cyclic polydialkylsiloxane and cyclic polyalkylphenylsiloxane Is mentioned.
Among these, silicone oil is particularly preferable in consideration of the influence on the environment such as the working environment.

The inventors have confirmed through preliminary tests that desired color display cannot be achieved even when colored non-electrophoretic particles as described in Patent Documents 2 and 3 are dispersed in a solvent.
That is, when the amount of the colored non-electrophoretic particles in the solvent is increased in order to enhance the color developed by the colored non-electrophoretic particles of Patent Documents 2 and 3, the viscosity of the entire dispersion (display liquid) increases, and the electrophoretic properties of the colored electrophoretic particles are increased. It has been found that migration tends to be inhibited, that is, the moving speed of colored migrating particles tends to decrease. Accordingly, it was found that when the ratio of the coloring agent in the colored non-electrophoretic particles was increased, the charge amount of the colored non-electrophoretic particles increased, and in this case also, the electrophoresis of the colored electrophoretic particles tended to be inhibited.

(C) Non-charged colored resin particle dispersion The non-charged colored resin particle dispersion of the present invention is obtained by dispersing the non-charged colored resin particles of the present invention in a non-polar solvent such as silicone oil. The content of the non-chargeable colored resin particles of the present invention in 100 parts by weight of the non-charged colored resin particle dispersion is usually about 2 to 40 parts by weight, preferably 5 to 30 parts by weight.
When the non-charged colored resin particle dispersion is used as an electrophoretic display device (image display device), the known chargeable colored resin particles are further included, and the content thereof is usually non-charged colored resin particle dispersion. The amount is about 0.2 to 30 parts by weight, preferably 0.5 to 20 parts by weight with respect to 100 parts by weight of the liquid.
The non-charged colored resin particle dispersion may contain known additives as long as the effects of the present invention are not impaired.

(D) Electrophoretic display device The electrophoretic display device of the present invention is obtained using a non-charged colored resin particle dispersion.
That is, in the electrophoretic display device of the present invention, the non-charged colored resin particles of the present invention develop a base color, and known charged colored resin particles develop a desired shape by electrophoresis, thereby displaying an image. To do.

  The electrophoretic display device of the present invention includes, for example, a structure in which a display layer made of a non-charged colored resin particle dispersion is sandwiched between a pair of substrates having electrodes. By applying a voltage between the electrodes, the chargeable colored resin particles used in combination move to one side in the pair of substrates according to the polarity of the applied voltage. In this apparatus, information is displayed using movement of the chargeable colored resin particles.

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

(Polyol Production Example 1)
To 6 g of toluene (manufactured by Wako Pure Chemical Industries) in a 50 mL glass container, 1 g of a polymer azo polymerization initiator (polydimethylsiloxane unit-containing polymer azo initiator manufactured by Wako Pure Chemical Industries, Ltd., trade name: VPS-1001) is added. Dissolved. There, 1.32 g of methyl methacrylate (MMA, manufactured by Mitsubishi Rayon Co., Ltd., trade name: Acryester M) and 2-hydroxyethyl methacrylate (HEMA, manufactured by Kyoeisha Chemical Co., Ltd., trade name: Light Ester OH-250) 28 g, 0.4 g of methacrylic acid (MAA, manufactured by Wako Pure Chemical Industries, Ltd.) and 0.02 g of lauryl mercaptan (produced by Wako Pure Chemical Industries, Ltd.) were added and mixed. The resulting mixture was heated and stirred in an oil bath at 80 ° C. for 5 hours. The obtained polymer solution was poured onto a 100 mm × 100 mm Teflon (registered trademark) sheet and dried in a dryer at 60 ° C. for 2 hours to obtain a film-like polyol (block copolymer).

[Weight average molecular weight (Mw)]
The weight average molecular weight (Mw) of the obtained polyol was measured.
The weight average molecular weight (Mw) in this invention means the polystyrene (PS) conversion weight average molecular weight measured using gel permeation chromatography (GPC).
Specifically, 4 mg of a sample was dissolved in 4 mL of tetrahydrofuran (THF) (permeation time: 6.0 ± 0.5 hr (complete dissolution)), filtered through a non-aqueous 0.45 μm chromatographic disk, and then subjected to the following conditions. And measured using a chromatograph. The average molecular weight of the sample was determined from a standard polystyrene calibration curve measured and prepared in advance.

Liquid chromatograph: Tosoh Corporation, trade name “Gel Permeation Chromatograph HLC-8320”
Guard column: manufactured by Tosoh Corporation, one product name “TSKguard SuperMP (HZ) -HX” (4.6 mm ID × 2 cm)
Column: Two TOSGE SuperMultipore HZ-H X (4.6 mm ID × 15 cm), manufactured by Tosoh Corporation
Column temperature: 40 ° C
Mobile phase: Tetrahydrofuran (THF)
Mobile phase flow rate: 0.2 mL / min
Detection: RI
Sample concentration: 0.5 g / mL THF
Injection volume: 20 microliters Measurement time: 25 min
Standard polystyrene for calibration curve: Showa Denko, trade name “shodex”
Weight average molecular weight: 5620000, 3120,000, 1250,000, 442000, 131000, 54000, 20000, 7590, 3450, 1320
In the method for preparing a calibration curve, the standard polystyrene for calibration curve was grouped into A and B, dissolved in THF so that the concentration was about 1% by weight (0.1 g / L), and 20 μL was injected. From these retention times, a calibration curve (primary equation) was created and used for molecular weight distribution measurement.

[Acid value]
The acid value of the obtained polyol was measured by the method shown below.
A 10 g sample is accurately weighed and placed in a stoppered Erlenmeyer flask, and 100 mL of an alcohol / ether mixture (1: 2) is added and dissolved. The solution is titrated with a 0.1N alcohol potassium hydroxide solution until a pale red color lasting 30 seconds is obtained using a phenolphthalene test solution as an indicator.
The acid value is determined by the following formula.
Acid value = (5.611 × a × F) / S
(Where S is the amount of sample collected (g), a is the consumption of 0.1N alcohol potassium hydroxide solution (mL), F is the titer of 0.1N alcohol potassium hydroxide solution)

(Polyol Production Examples 2 to 5)
A polyol was obtained in the same manner as in Polyol Production Example 1 except that various materials were used in the amounts shown in Table 1.
Table 1 shows the materials used in the production of the polyol and the amount thereof, the weight average molecular weight (Mw) of the obtained polyol and the acid value thereof.

(Production Example 1 of Pigment Dispersion)
In a 300 mL glass bead pot containing 500 g of zirconia beads having a diameter of 5 mm, 50 g of ethyl acetate (manufactured by Wako Pure Chemical Industries) as a non-aqueous polar solvent, titanium oxide as a pigment (average primary particle size: 180 nm, Ishihara Sangyo Co., Ltd.) Product name: PT-501R) (50 g) and a polymer dispersant as a pigment surface treatment agent (polymer pigment dispersant, Ajinomoto Fine Techno Co., Ltd., trade name: Ajisper PB881) (5.0 g) were added, and room temperature ( The pigment was dispersed by a bead mill at 25 ° C. for 24 hours to obtain a pigment dispersion.

(Production Example 2 of Pigment Dispersion)
Instead of the polymer dispersant PB881 as the pigment surface treatment agent, a pigment dispersant was used except that a polymer dispersant (Ajinomoto Fine Techno Co., Ltd., aluminum coupling agent, trade name: Plenact AL-M) was used. A pigment dispersion was obtained in the same manner as in Liquid Production Example 1.

(Production Example 3 of Pigment Dispersion)
Instead of titanium oxide PT-501R as a pigment, titanium oxide (average primary particle diameter: 70 nm, manufactured by Ishihara Sangyo Co., Ltd., trade name: PT401M) was used in the same manner as in Production Example 1 for pigment dispersion. A pigment dispersion was obtained.
Table 2 shows the materials used in the production of the pigment dispersion and the amounts thereof.

Example 1
(Dispersion process)
As a nonpolar solvent (continuous phase), 25 g of isoparaffin (manufactured by Idemitsu Kosan Co., Ltd., trade name: IP Solvent 2028) was used.
4.7 g of ethyl acetate as a non-aqueous polar solvent was added to 0.63 g (containing 0.3 g of pigment) of the pigment dispersion obtained in Production Example 1 of the pigment dispersion, and further obtained in Production Example 1 of the polyol. A solution prepared by dissolving 0.8 g of polyol in 5 g of ethyl acetate and 0.12 g of isocyanurate type polyisocyanate of hexamethylene diisocyanate as a polyfunctional isocyanate (crosslinking agent) (manufactured by Asahi Kasei Chemical Co., Ltd., trade name: Duranate TPA-100) Was added and dissolved to obtain 11.25 g of a reaction phase (mixture A: including a total amount of 10 g of ethyl acetate as a water-insoluble polar solvent). Here, the polyol is insoluble in isoparaffin, which is a nonpolar solvent, and has a segment made of a block copolymer (acrylic polymer) having an affinity for ethyl acetate, which is a nonaqueous polar solvent, and is compatible with isoparaffin, which is a nonpolar solvent. And a segment made of a silicone chain having properties.
Into a 50 mL glass bottle, 25 g of isoparaffin was added as a continuous phase, and the reaction phase was added over about 5 minutes while stirring using an ultrasonic homogenizer. After the addition, the resulting mixture was subsequently stirred for 10 minutes and subjected to an emulsification dispersion treatment to obtain an emulsion (mixture B).
(Removal process)
Next, the obtained emulsion was put into a 50 mL eggplant flask, and the mixture was heated at 90 ° C. for 2 hours with stirring to remove ethyl acetate to obtain a mixture C.

(Crosslinking process)
Next, 0.002 g of triethylamine (Et ₃ N) as a crosslinking catalyst is added to the emulsion from which ethyl acetate has been removed, and the mixture is stirred at 95 ° C. for 1 hour to crosslink the polyol with a polyfunctional isocyanate and coat with a crosslinked resin. A dispersion containing the colored resin particles was obtained.
(Reaction process)
Next, 0.34 g of stearylamine (molecular weight: 269.51) as an amino group-containing compound was added to the obtained dispersion, and the mixture was reacted at 60 ° C. for 4 hours with stirring using a magnetic stirrer to obtain a colored resin. 26.59 g of a particle dispersion was obtained.
(Post-processing)
After completion of the reaction, the colored resin particles were separated from the dispersion using a centrifuge (Kubota, model: 9730), and again washed twice in 25 g of isoparaffin (continuous phase). 26.59 g of dispersion was obtained.

(Evaluation)
[Average particle size]
The average particle diameter of the colored resin particles in the obtained dispersion was measured. In the present invention, the “average particle size” means a Z average particle size measured using a method called a dynamic light scattering method.
Specifically, a dispersion of colored resin particles is irradiated with a laser beam using a particle size distribution analyzer (Spectras Malvern Instruments Ltd, product name: Zetasizer Nano ZS) and its data analysis software. Then, the scattered light intensity scattered from the resin particles is measured with a time change in units of microseconds, and the scattered intensity distribution resulting from the detected resin particles is applied to the normal distribution, and an average particle diameter of 388 nm is obtained by the cumulant analysis method. It was.

[Dispersibility (dispersion stability)]
Using a centrifuge (Tomy Seiko Co., Ltd., trade name: tabletop centrifuge LC-200), 40 mL of a dispersion of colored resin particles placed in a 50 mL conical tube is centrifuged at 5000 rpm for 30 minutes, Thereafter, the dispersed state of the particles in the extracted conical tube was visually observed, and the dispersibility was evaluated according to the following criteria.
◯: Not settled Δ: Precipitated particles and non-settled particles coexist ×: Sedimented The obtained colored resin particle dispersion was evaluated as “Good” and had good dispersibility.

[Polarity (Chargeability)]
As a measurement sample, a dispersion (about 5 mL) of colored resin particles having a solid content of 5% by weight was prepared from the obtained dispersion of colored resin particles.
Next, two glass plates coated with indium tin oxide (ITO) on one side (width 8 mm, length 100 mm, thickness 0.7 mm: manufactured by Matsunami Glass Industry Co., Ltd., trade name: ITO coated glass EAGLE XG) A parallel flat plate (jig) was prepared in which the distance between the glass plates was 1 mm with the spacer with the copper tape affixed between the glass plates inside. Next, the jig was immersed in the measurement sample, a voltage of +100 V was applied to the left side of the jig and left for 10 seconds. After 10 seconds had elapsed, the jig was pulled up from the measurement sample. If particles are attached to the left (one) glass plate of the jig, the particle polarity is negative, and if particles are attached to the right (other) glass plate, the particle polarity is determined to be positive. The sample did not clearly show polarity (chargeability).

[Charge amount]
As a measurement sample, a dispersion (about 5 mL) of colored resin particles having a solid content of 10% by weight was prepared from the obtained dispersion of colored resin particles.
Then, two glass plates (width 20 mm, length 100 mm, thickness 0.7 mm, manufactured by Matsunami Glass Industrial Co., Ltd., trade name: ITO coated glass EAGLE XG) coated with indium tin oxide (ITO) on one side were prepared. As shown in FIG. 1, a Teflon (registered trademark) film (width 20 mm, length 25 mm) having a thickness of 50 μm is pasted as a spacer on the coated surface of one glass substrate, and the coated surfaces of two glass plates are on the inside. In this state, a parallel plate (tool) sandwiched between spacers was used. A preliminarily prepared measurement sample is infiltrated by capillary action into a gap (width 25 mm, length 20 mm, thickness 50 μm) between the coated surfaces of indium tin oxide (ITO) on two glass plates. It was. Next, both sides of the jig were connected to a measuring device (trade name: KEITHLEY6514, manufactured by KEITHLEY), and the measured value (total charge amount) obtained by applying a voltage of +10 V for 60 seconds was divided by the measurement area, and charged. A quantity of 0.7 nC / cm ² was determined.

[Confirmation of amide group in reaction product]
The presence or absence of the amide group of the reaction product in the resin component of the colored resin particles was confirmed.
Specifically, the colored resin particles (about 0.2 mg) separated from the obtained dispersion and KBr powder (about 160 mg) are mixed and pulverized in a mortar, and the mixed powder obtained by a tablet press molding machine has a diameter. It was molded into a tablet of about 13 mm, and IR measurement was performed using a Fourier transform infrared spectrophotometer (manufactured by Nicolet, trade name: MAGNA-560). The absorption wavelength peculiar to the colored resin particles was found from the difference spectrum of the obtained infrared absorption spectrum and the functional group information was obtained. As a result, a peak derived from an amide group was confirmed in the vicinity of 3300 cm ⁻¹ .
Table 3 shows the materials used, their amounts, and evaluation results, including the following examples and comparative examples.

(Example 2)
A colored resin in the same manner as in Example 1 except that 0.16 g of octylamine (molecular weight: 129.24, manufactured by Kao Corporation, trade name: Farmin) was used instead of stearylamine as the amino group-containing compound. A dispersion containing particles was obtained.
The obtained colored resin particles had an average particle diameter of 447 nm, and an IR measurement confirmed a peak derived from an amide group in the vicinity of 3300 cm ⁻¹ . The obtained colored resin particles had good dispersibility in a nonpolar solvent, had a charge amount of 1.2 nC / cm ² , and did not clearly show chargeability.

(Example 3)
Coloring in the same manner as in Example 1 except that 0.44 g of silicone chain amine (molecular weight: 350, manufactured by Momentive Inc., trade name: MCR-A11) was used instead of stearylamine as the amino group-containing compound. A dispersion containing resin particles was obtained.
The obtained colored resin particles had an average particle diameter of 390 nm, and an amide group-derived peak was confirmed in the vicinity of 3300 cm ⁻¹ by IR measurement. The obtained colored resin particles had good dispersibility in a nonpolar solvent, had a charge amount of 4.5 nC / cm ² , and did not clearly show chargeability.

Example 4
A dispersion containing colored resin particles was obtained in the same manner as in Example 1 except that 0.51 g of stearylamine (molecular weight: 269.51) was used as the amino group-containing compound.
The resulting colored resin particles had an average particle diameter of 436 nm, and an IR measurement confirmed a peak derived from an amide group in the vicinity of 3300 cm ⁻¹ . The obtained colored resin particles had good dispersibility in a nonpolar solvent, had a charge amount of 0.6 nC / cm ² , and did not clearly show chargeability.

(Example 5)
A dispersion containing colored resin particles was obtained in the same manner as in Example 1 except that 0.17 g of stearylamine (molecular weight: 269.51) was used as the amino group-containing compound.
The obtained colored resin particles had an average particle diameter of 380 nm, and an IR measurement confirmed a peak derived from an amide group in the vicinity of 3300 cm ⁻¹ . The obtained colored resin particles had good dispersibility in a nonpolar solvent, had a charge amount of 0.7 nC / cm ² , and did not clearly show chargeability.

(Example 6)
A dispersion containing colored resin particles was prepared in the same manner as in Example 1 except that silicone oil (trade name: KF-96L-2CS, manufactured by Shin-Etsu Chemical Co., Ltd.) was used instead of isoparaffin as the nonpolar solvent. Obtained.
The obtained colored resin particles had an average particle diameter of 365 nm, and an amide group-derived peak was confirmed in the vicinity of 3300 cm ⁻¹ by IR measurement. The obtained colored resin particles had good dispersibility in a nonpolar solvent, had a charge amount of 0.7 nC / cm ² , and did not clearly show chargeability.

(Example 7)
Aside from using the polyol obtained in polyol production example 2 in place of the polyol obtained in polyol production example 1, 0.17 g of stearylamine (molecular weight: 269.51) as the amino group-containing compound was used. In the same manner as in Example 1, a dispersion containing colored resin particles was obtained.
The obtained colored resin particles had an average particle diameter of 370 nm, and an IR measurement confirmed a peak derived from an amide group in the vicinity of 3300 cm ⁻¹ . Moreover, the obtained colored resin particles had good dispersibility in a nonpolar solvent, had a charge amount of 1.5 nC / cm ² , and did not clearly show chargeability.

(Example 8)
Instead of using the polyol obtained in polyol production example 3 instead of the polyol obtained in polyol production example 1, 0.09 g of stearylamine (molecular weight: 269.51) as an amino group-containing compound was used. In the same manner as in Example 1, a dispersion containing colored resin particles was obtained.
The obtained colored resin particles had an average particle diameter of 365 nm, and an amide group-derived peak was confirmed in the vicinity of 3300 cm ⁻¹ by IR measurement. The obtained colored resin particles had good dispersibility in a nonpolar solvent, had a charge amount of 2.3 nC / cm ² , and did not clearly show chargeability.

Example 9
Instead of using the polyol obtained in polyol production example 5 in place of the polyol obtained in polyol production example 1, 0.01 g stearylamine (molecular weight: 269.51) as the amino group-containing compound was used. In the same manner as in Example 1, a dispersion containing colored resin particles was obtained.
The obtained colored resin particles had an average particle diameter of 361 nm, and an IR measurement confirmed a peak derived from an amide group in the vicinity of 3300 cm ⁻¹ . Further, the obtained colored resin particles had good dispersibility in a nonpolar solvent, had a charge amount of 9.3 nC / cm ² , and did not clearly show chargeability.

(Example 10)
Instead of the polyol obtained in Polyol Production Example 1, a silicone-acrylic graft copolymer (acid value 14 mgKOH / g, hydroxyl value 120 mgKOH / g, manufactured by Toagosei Co., Ltd., trade name: Reeta GS-1015) was used. A dispersion containing colored resin particles was obtained in the same manner as in Example 1 except that 0.10 g of stearylamine (molecular weight: 269.51) as an amino group-containing compound was used.
The obtained colored resin particles had an average particle diameter of 582 nm, and an IR measurement confirmed a peak derived from an amide group in the vicinity of 3300 cm ⁻¹ . The obtained colored resin particles had good dispersibility in a nonpolar solvent, had a charge amount of 0.6 nC / cm ² , and did not clearly show chargeability.

(Example 11)
Colored resin particles in the same manner as in Example 1, except that the pigment dispersion obtained in Production Example 2 of the pigment dispersion was used instead of the pigment dispersion obtained in Production Example 1 of the pigment dispersion. A dispersion containing was obtained.
The obtained colored resin particles had an average particle diameter of 428 nm, and an IR measurement confirmed a peak derived from an amide group in the vicinity of 3300 cm ⁻¹ . The obtained colored resin particles had good dispersibility in a nonpolar solvent, had a charge amount of 2.1 nC / cm ² , and did not clearly show chargeability.

(Example 12)
Colored resin particles in the same manner as in Example 1, except that the pigment dispersion obtained in Production Example 3 of pigment dispersion was used instead of the pigment dispersion obtained in Production Example 1 of pigment dispersion. A dispersion containing was obtained.
The obtained colored resin particles had an average particle diameter of 248 nm, and an IR measurement confirmed a peak derived from an amide group in the vicinity of 3300 cm ⁻¹ . Further, the obtained colored resin particles had good dispersibility in a nonpolar solvent, had a charge amount of 3.8 nC / cm ² , and did not clearly show chargeability.

(Comparative Example 1)
A dispersion containing colored resin particles was obtained in the same manner as in Example 9, except that stearylamine as the amino group-containing compound was not used.
The obtained colored resin particles had an average particle diameter of 338 nm and good dispersibility in a nonpolar solvent, but had a charge amount of 70.0 nC / cm ² and clearly showed chargeability. It was.

(Comparative Example 2)
Instead of using the polyol obtained in polyol production example 4 instead of the polyol obtained in polyol production example 1, 0.85 g of stearylamine (molecular weight: 269.51) as the amino group-containing compound was used. In the same manner as in Example 1, a dispersion containing colored resin particles was obtained.
The obtained colored resin particles were strongly aggregated, and the average particle diameter and charge amount could not be measured. In addition, an amide group-derived peak was confirmed in the vicinity of 3300 cm ⁻¹ by IR measurement.

  From the results of Table 3, the colored resin particles obtained by reacting the carboxyl group in the resin with the amino group of the amino group-containing compound in the resin-coated pigment particle in which the pigment particle is coated with the resin by the in-liquid drying method are It can be seen that it has a low non-chargeability and dispersibility.

Claims (9)

A segment comprising a silicone chain having affinity for a nonpolar solvent and a segment comprising an acrylic polymer having affinity for a non-aqueous polar solvent, and having a carboxyl group and an acid value of 1 to 200 mgKOH / g Obtaining a mixed liquid A comprising a polyol insoluble in a nonpolar solvent, a pigment, a polyfunctional isocyanate, and the nonaqueous polar solvent;
Mixing the mixture A and the nonpolar solvent to obtain a mixture B;
Removing the non-aqueous polar solvent from the mixed solution B to obtain a mixed solution C;
In the mixed solution C, a step of obtaining a mixed solution D containing a resin-coated pigment by coating the surface of the pigment with a crosslinked resin obtained by crosslinking the polyol with the polyfunctional isocyanate;
An amino group-containing compound is added to the mixed solution D, and the cross-linked resin of the resin-coated pigment and the amino group-containing compound are added to the amino group-containing compound with respect to 1 mol of the carboxyl group derived from the polyol. And a step of obtaining 0.2 to 1.5 moles of groups to obtain non-chargeable colored resin particles.   The method for producing non-chargeable colored resin particles according to claim 1, wherein the amino group-containing compound is an aliphatic amine or an amino group-containing silicone compound.   The method for producing non-chargeable colored resin particles according to claim 1 or 2, wherein the non-aqueous polar solvent has a boiling point lower than the boiling point of the non-polar solvent and 50 to 200 ° C.   The method for producing non-chargeable colored resin particles according to any one of claims 1 to 3, wherein the non-polar solvent is silicone oil or paraffinic hydrocarbon.   The method for producing non-chargeable colored resin particles according to any one of claims 1 to 4, wherein the non-aqueous polar solvent is an ester or a ketone.   The method for producing non-chargeable colored resin particles according to any one of claims 1 to 5, wherein the polyol is an AB type block copolymer or a graft copolymer. The non-charged colored resin particles are enclosed between ITO electrodes that are parallel flat plates with a distance between the electrodes of 50 μm in a state where the solid content concentration is dispersed in the non-polar solvent at a solid concentration of 10% by weight. The method for producing non-chargeable colored resin particles according to any one of claims 1 to 6, which exhibits a charge amount of 10 nC / cm ² or less when applied for ² seconds. A method for producing a non-chargeable colored resin particle dispersion obtained by dispersing the non-charged colored resin particles according to claim 7 in a nonpolar solvent. A method for producing an electrophoretic display device using the non-chargeable colored resin particle dispersion according to claim 8.