JP2005220213A - Crosslinked polymer particle powder and manufacturing method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a crosslinked polymer particle powder excellent in the dispersion into an organic solvent, a molten resin, and the like, and a manufacturing method therefor. <P>SOLUTION: The crosslinked polymer particle powder contains 100 pts. mass of a crosslinked polymer particle and 1-100 pts. mass of a dispersant shown by the formula (1): T<SP>1</SP>O-(RO)<SB>n</SB>(EO)m-T<SP>2</SP>(1). In the formula (1), T<SP>1</SP>is hydrogen atom, a 1-18C alkyl group or a 2-18C alkenyl group; T<SP>2</SP>is hydrogen atom, sulfonic acid (sulfonate) group, carboxylic acid (carboxylate) group, phosphoric acid (phosphate) group, amino group or ammonium group; RO is a 3-18C oxyalkylene group; and EO is an oxyethylene group. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a crosslinked polymer particle powder, and more particularly, has excellent dispersibility in an organic solvent, a molten resin, and the like, and is particularly useful for an ink for inkjet and a light scattering material for a light scattering sheet. The present invention relates to polymer particle powder.

  Crosslinked polymer particles (especially fine particles) with excellent heat resistance and solvent resistance and controlled average particle diameter are used as surface slip property modifiers for plastic films, ink viscosity improvers, etc. ing. Further, the hollow crosslinked polymer particles are useful as a white pigment for ink, which is less likely to cause precipitation, and as a light scattering material for a light scattering sheet. However, currently used crosslinked polymer particles are water dispersions or dry powders that are inferior in dispersibility, and are inferior in dispersibility in organic solvents, molten resins, etc., so there is a limitation in the formulation of ink. Or a sufficient light scattering function cannot be exhibited.

As a technique for pulverizing polymer particles, for example, Patent Document 1 uses a special drying apparatus, and at the same time contains a formalin condensate of polyvinyl alcohol or melamine sulfonate to redisperse in water. A method for improving the above is disclosed. However, this method has a problem in that dispersibility in an organic solvent, a molten resin, or the like cannot be improved, and drying equipment becomes expensive. Similarly, Patent Document 2 discloses a method of using an oligomeric arylsulfonic acid-formaldehyde condensation product as a drying aid. However, this method cannot improve the dispersibility in an organic solvent, a molten resin, or the like, and when such a drying aid is used, it is colored yellow and the degree of coloring progresses over time. .
Japanese Patent Laid-Open No. 11-292978 JP 2002-138145 A

  The present invention has been made in view of the above-described problems of the prior art, and an object thereof is to provide a crosslinked polymer particle powder excellent in dispersibility in an organic solvent, a molten resin, or the like.

  In order to achieve the above object, the present invention provides the following crosslinked polymer particle powder.

[1] A crosslinked polymer particle powder containing 100 parts by mass of a crosslinked polymer particle and 1 to 100 parts by mass of a dispersant represented by the following formula (1).
^{T 1 O- (RO) n (} EO) m-T 2 ... (1)
(T ¹ is a hydrogen atom, an alkyl group having 1 to 18 carbon atoms or an alkenyl group having 2 to 18 carbon atoms, and T ² is a hydrogen atom, a sulfonic acid (salt) group, a carboxylic acid (salt) group, phosphoric acid ( Salt) group, amino group or ammonium group, RO is an oxyalkylene group having 3 to 18 carbon atoms, EO represents an oxyethylene group, n is an integer of 1 to 50, and m is an integer of 0 to 200. Yes, n RO groups are of the same type or different types, and n RO groups and m EO groups are block bonds or random bonds.)

[2] The crosslinked polymer particle powder according to [1], wherein the crosslinked polymer particles are divinylbenzene copolymer particles.

[3] The crosslinked polymer particle powder according to [1] or [2], wherein the crosslinked polymer particle is a hollow particle.

[4] A non-aqueous crosslinked polymer particle dispersion obtained by dispersing the crosslinked polymer particle powder according to any one of [1] to [3] in an organic solvent.

[5] An ink containing the crosslinked polymer particle powder according to any one of [1] to [3].

[6] A light scattering material comprising the crosslinked polymer particle powder according to any one of [1] to [3].

[7] A step of emulsion polymerizing a polymerizable monomer containing a crosslinkable radical polymerizable monomer in the presence of seed particles (i) in an aqueous medium to obtain a dispersion of the crosslinked polymer particles (ii), and A step of adding 1 to 100 parts by mass of a dispersant represented by the following formula (2) to 100 parts by mass of the dispersion of the crosslinked polymer particles (ii), followed by drying to obtain a crosslinked polymer particle powder; A method for producing a crosslinked polymer particle powder comprising:
^{T 1 O- (RO) n (} EO) m-T 2 ... (2)
(T ¹ is a hydrogen atom, an alkyl group having 1 to 18 carbon atoms or an alkenyl group having 2 to 18 carbon atoms, and T ² is a hydrogen atom, a sulfonic acid (salt) group, a carboxylic acid (salt) group, phosphoric acid ( Salt) group, amino group or ammonium group, RO is an oxyalkylene group having 3 to 18 carbon atoms, EO represents an oxyethylene group, n is an integer of 1 to 50, and m is an integer of 0 to 200. Yes, n RO groups are of the same type or different types, and n RO groups and m EO groups are block bonds or random bonds.)

  According to the crosslinked polymer particle powder of the present invention, since the crosslinked polymer particles are composed of a crosslinked polymer, the particles are not easily bonded and aggregated, and therefore have excellent dispersibility in an organic solvent or a molten resin. Become. Moreover, since the predetermined | prescribed dispersing agent shown by said Formula (1) is contained with a crosslinked polymer particle, it becomes the thing excellent in the dispersibility to an organic solvent or molten resin further.

  BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the best mode for carrying out the present invention (hereinafter sometimes referred to as “embodiment”) will be specifically described, but the present invention is not limited to the following embodiment, It should be understood that design changes, improvements, and the like can be made as appropriate based on ordinary knowledge of those skilled in the art without departing from the spirit of the invention.

One embodiment of the crosslinked polymer particle powder of the present invention is a crosslinked polymer particle powder containing 100 parts by mass of crosslinked polymer particles and 1 to 100 parts by mass of a dispersant represented by the following formula (1). Is the body.
^{T 1 O- (RO) n (} EO) m-T 2 ... (1)
(T ¹ is a hydrogen atom, an alkyl group having 1 to 18 carbon atoms or an alkenyl group having 2 to 18 carbon atoms, and T ² is a hydrogen atom, a sulfonic acid (salt) group, a carboxylic acid (salt) group, phosphoric acid ( Salt) group, amino group or ammonium group, RO is an oxyalkylene group having 3 to 18 carbon atoms, EO represents an oxyethylene group, n is an integer of 1 to 50, and m is an integer of 0 to 200. Yes, n RO groups are of the same type or different types, and n RO groups and m EO groups are block bonds or random bonds.)

  In the case where n RO groups and m EO groups are block bonds, the arrangement order of RO groups and EO groups may be any.

  By comprising in this way, since crosslinked polymer particle | grains consist of a bridge | crosslinked polymer, particle | grains are hard to couple | bond together and aggregate, Therefore, it becomes the thing excellent in the dispersibility to an organic solvent or molten resin. Moreover, since the predetermined | prescribed dispersing agent shown by said Formula (1) is contained with a crosslinked polymer particle, it becomes the thing excellent in the dispersibility to an organic solvent or molten resin further. Here, the organic solvent includes, for example, the organic solvent used in the non-aqueous crosslinked polymer particle dispersion of the present invention described below, and the molten resin includes, for example, polyethylene, polypropylene, polystyrene, and MS resin. (MMA / styrene copolymer resin), styrene / butadiene copolymer resin, AS resin, ABS resin, acrylic resin, nylon resin, polyamide, polyacetal, polycarbonate, PBT resin, PET resin, PPS resin, liquid crystal polymer, polyarylate, polysulfone , Polyethersulfone, norbornene resin, cycloolefin polymer, polymethylpentene, polyethernitrile, polyketone, PEEK, thermoplastic elastomer (RB, EP, EPDM, etc.), fluorine resin, ionomer resin, nitrile resin, ethylene vinyl alcohol Thermosetting resins such as phenolic resins, diallyl phthalate resins, unsaturated polyester resins, epoxy resins, urea resins, and melamine / melamine phenolic resins are uncured. It contains a resin melted in

  The cross-linked polymer particles in the present embodiment refer to particles in which the inside of the particles obtained by addition polymerization, condensation polymerization or the like is cross-linked, such as cross-linked styrene particles, cross-linked acrylic particles, cross-linked urethane-based particles, cross-linked silicone-based particles. Examples thereof include particles, crosslinked alkyd particles, and crosslinked polyester particles.

  The crosslinked polymer particles in the present embodiment are usually obtained by drying these aqueous dispersions. The aqueous dispersion of the crosslinked polymer particles can be obtained by a method such as emulsion polymerization, miniemulsion polymerization, dispersion polymerization, or by emulsifying and dispersing the polymer in water. As a method of crosslinking the polymer fine particles, a method of allowing crosslinking to proceed during polymerization using a polyfunctional monomer, a method of adding a crosslinking agent to the functional group-containing polymer particles, and a polymer particle having an unsaturated double bond Examples include a method of irradiating with an electron beam.

The crosslinked polymer particles are particularly preferably divinylbenzene copolymer particles because of excellent dispersibility. Since the divinylbenzene copolymer particles have high hardness, the cohesive force between the particles is small and the redispersibility is excellent. Divinylbenzene copolymer particles are preferred because they are further excellent in heat resistance and solvent resistance. The content of divinylbenzene in the divinylbenzene copolymer is preferably 10% by mass or more, more preferably 20% by mass or more, and particularly preferably 25% by mass or more. If it is less than 10% by mass, the crosslinked polymer particle powder may be inferior in dispersibility, heat resistance and solvent resistance. In addition to divinylbenzene, the copolymer component contains two or more copolymerizable double bonds such as polyvalent acrylate compounds represented by ethylene glycol dimethacrylate and trimethylolpropane tri (meth) acrylate. The component derived from the crosslinkable compound is preferred. The number of copolymerizable double bonds is preferably two.

  Examples of the polyvalent acrylate compound contained in the divinylbenzene copolymer include polyethylene glycol diacrylate, 1,3-butylene glycol diacrylate, 1,6-hexane glycol diacrylate, neopentyl glycol diacrylate, and polypropylene glycol diacrylate. Diacrylate compounds such as 2,2′-bis (4-acryloxypropyloxyphenyl) propane and 2,2′-bis (4-acryloxydiethoxyphenyl) propane; trimethylolpropane triacrylate, trimethylolethanetri Triacrylate compounds such as acrylate and tetramethylolmethane triacrylate; tetraacrylate compounds such as tetramethylolmethane tetraacrylate; ethylene glycol dimethacrylate Diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate, 1,4-butylene glycol dimethacrylate, 1,6-hexane glycol dimethacrylate, neopentyl glycol dimethacrylate, Dimethacrylate compounds such as dipropylene glycol dimethacrylate, polypropylene glycol dimethacrylate, 2,2′-bis (4-methacryloxydiethoxyphenyl) propane; trimethacrylate compounds such as trimethylolpropane trimethacrylate, trimethylolethane trimethacrylate, etc. Is mentioned. Of these, ethylene glycol dimethacrylate or trimethylolpropane trimethacrylate is preferred. Two or more of these crosslinkable compounds may be copolymerized with divinylbenzene to form a copolymer.

  As described above, the copolymer component other than divinylbenzene contained in the divinylbenzene copolymer particles is preferably composed of only a crosslinkable compound in terms of hardness, but contains a component derived from a polymerizable monovinyl monomer. May be. Examples of polymerizable monovinyl monomers include aromatic monovinyl compounds such as styrene, ethylvinylbenzene, α-methylstyrene, fluorostyrene, and vinylpyridine; vinyl cyanide compounds such as acrylonitrile and methacrylonitrile; butyl acrylate, ethyl acrylate, 2- Acrylic acid ester monomers such as ethylhexylethyl acrylate, cyclohexyl acrylate, hydroxyethyl acrylate, glycidyl acrylate, polyoxyethylene acrylate, N, N′-dimethylaminoethyl acrylate; butyl methacrylate, 2-ethylhexyl methacrylate, methyl methacrylate, cyclohexyl methacrylate, hydroxy Ethyl methacrylate, glycidyl methacrylate, polyoxyethylene methacrylate Methacrylic acid ester monomers such as N, N'-dimethylaminoethyl methacrylate; acrylic acid, methacrylic acid, maleic acid, itaconic acid and other mono- or dicarboxylic acid and dicarboxylic acid anhydrides; acrylamide, dimethylacrylamide, methacrylic acid Examples thereof include amide monomers such as amides. Moreover, within the range allowed in terms of polymerization rate and polymerization stability, conjugated double bond compounds such as butadiene and isoprene, vinyl ester compounds such as vinyl acetate; 4-methyl-1-pentene, and other α-olefins Compounds can also be used. Of these, styrene and ethyl vinyl benzene are particularly preferable. Two or more of these polymerizable monomers may be used.

  Further, the crosslinked polymer particles are preferably hollow particles. The hollow particles make it difficult to settle when the crosslinked polymer particle powder is redispersed in an organic solvent or a molten resin. Moreover, functions, such as concealment property and light scattering property, can be improved by using hollow particles. That is, by using hollow particles, the refractive index of light is greatly different between the polymer portion forming the outer shell and the internal space, so that the effect of scattering and shielding light is exhibited. Such crosslinked polymer particles can be effectively used as a light scattering component of a light scattering material. Moreover, even if a crosslinked polymer particle is a solid particle, it has functions, such as concealment property and light scattering property, and can be used as a light scattering material. The light scattering material containing crosslinked polymer particles is, for example, disposed on the surface of a transparent base material made of a transparent plastic plate or film such as inorganic glass or polyethylene terephthalate to form an optical article, and scatters light incident on the surface. Can be used for.

  The average particle size of the primary particles of the crosslinked polymer particles in the present embodiment is usually 0.01 to 100 μm, preferably 0.02 to 50 μm, more preferably 0.05 to 20 μm, and most preferably 0.1 μm to 10 μm. If it is less than 0.01 μm, the dispersibility is inferior, and the cross-linked polymer particles exceeding 100 μm do not have the problem of dispersibility, which is the subject of the present invention. The primary particles refer to single particles that are not aggregated, and the shape thereof may be a spherical shape, a long spherical shape (spheroid), or any other irregular shape such as a deformed spherical shape or a long spherical shape. Further, the average particle diameter refers to the volume average particle diameter (the same applies hereinafter).

  As the degree of crosslinking of the crosslinked polymer particles in the present embodiment, the toluene insoluble content contained in the crosslinked polymer particles is preferably 40% by mass or more, more preferably 60% by mass or more, and particularly preferably 80%. It is at least mass%. If it is lower than 40% by mass, the dispersibility may be lowered. The toluene-insoluble matter refers to a portion that remains without being dissolved when the crosslinked polymer particles in the crosslinked polymer particle powder are dissolved in toluene. The measurement is performed by the following method.

(Toluene insoluble matter measurement method)
The dispersant is removed from the crosslinked polymer particle powder by Soxhlet extraction using water as an extraction solvent, and water is further removed by vacuum drying at 100 ° C. About 1 g of the obtained crosslinked polymer particles were collected and weighed accurately ((w1) g), immersed in 100 mL of toluene, stirred at 80 ° C. for 6 hours, and then centrifuged at 15000 rpm for 30 minutes using a centrifuge. Then, after collecting a part of the separated liquid ((v) mL), it was evaporated to dryness and solidified, and the obtained residual solid (toluene soluble part (w2) g) was weighed, and insoluble in toluene by the following formula (3) Calculate minutes.
Toluene insoluble matter (mass%) = ((w1-w2 × (100 / v)) / w1) × 100 (3)

The dispersant contained in the crosslinked polymer particle powder of the present embodiment is a compound represented by the above formula (1), and the above-mentioned n RO groups and m EO groups are block bonds. The order of the arrangement of the RO group and the EO group may be any. In the above formula (1), when the numerical ranges of n and m and the structural ranges of T ¹ , T ² , RO and EO are other than the above, the dispersibility is inferior. The T ^1, and more preferably an alkyl group or an alkenyl group having 3 to 12 carbon atoms, particularly preferably an alkenyl group having 3 to 7 carbon atoms. T ² is more preferably a hydrogen atom or a sulfonate group, and particularly preferably an ammonium sulfonate group. Specific examples of the dispersant are trade names, Latemul PD-104 manufactured by Kao Co., Ltd., Emulgen LS series, Emulgen MS series, Emulgen PP series, Fine Surf NDB series, IDEP series, Wonder Surf NDR series manufactured by Aoki Yushi Kogyo Co., Ltd., CP series, ID series, S series, NIKKOL PBC series manufactured by Nikko Chemicals, NIKKOL PEN series, EMALEX DAPE manufactured by Nippon Emulsion Co., etc.

  In the crosslinked polymer particle powder of the present embodiment, the content of the dispersant is 1 to 100 parts by weight, preferably 2 to 50 parts by weight, based on 100 parts by weight of the crosslinked polymer particles. Preferably it is 3-30 mass parts. When the amount is less than 1 part by mass, the dispersibility is inferior, and when the amount is more than 100 parts by mass, no further improvement in the dispersion effect is recognized, resulting in an increase in cost.

  Next, an embodiment of a method for producing a crosslinked polymer particle powder of the present invention will be described.

  In the method for producing a crosslinked polymer particle powder according to the present embodiment, a polymerizable monomer containing a crosslinkable radically polymerizable monomer is emulsion-polymerized in an aqueous medium in the presence of seed particles (i) to form crosslinked polymer particles ( A dispersion of ii) is prepared, and then a specific dispersant is added to the obtained dispersion of crosslinked polymer particles (ii), followed by drying to obtain a crosslinked polymer particle powder. is there. Here, in the present embodiment, the “seed particle (i)” is a particle serving as a nucleus when the crosslinked radical polymerizable monomer is emulsion-polymerized to produce the crosslinked polymer particle (ii). The crosslinkable radical polymerizable monomer is polymerized and grown so as to cover the surface layer of the seed particles or to swell the inside of the seed particles. Hereinafter, the “seed particles (i)” may be referred to as “first polymer particles (i)”. Examples of a method for producing such a dispersion of crosslinked polymer particles (ii) include Japanese Patent No. 2897051 as solid particles, and Japanese Patent No. 2646620, Japanese Patent Application Laid-Open No. 2002-241448 as hollow particles. A particularly preferable form as a production method when the crosslinked polymer particle powder is made into a hollow particle powder is that a specific monomer (first polymerizable monomer) (a) is emulsion-polymerized in an aqueous medium to form first polymer particles ( The dispersion of i) is prepared, and then the surface layer of the first polymer particles (i) is coated with a shell layer containing a second polymer derived from the specific second polymerizable monomer (b) to form crosslinked polymer particles ( A dispersion of ii) is prepared, and then a specific dispersant is added to the obtained dispersion of crosslinked polymer particles (ii), followed by drying to obtain a crosslinked polymer particle powder. is there. According to this embodiment, the above-mentioned crosslinked polymer particle powder of the present invention can be produced. Hereafter, the manufacturing method in this Embodiment is demonstrated concretely for every process.

(Preparation of dispersion of first polymer particles (i))
In the present embodiment, first, unsaturated carboxylic acid (a-1) (hereinafter sometimes referred to as “monomer (a-1)”) and radical polymerizable monomer (a-2) (hereinafter referred to as “monomer ( a dispersion of the first polymer particles (i) is prepared by emulsion polymerization of the first polymerizable monomer (a) consisting of “a-2)” in some cases in an aqueous medium. Water can be used as the aqueous medium.

  Examples of the monomer (a-1) include mono- or dicarboxylic acids such as (meth) acrylic acid, crotonic acid, maleic acid, fumaric acid and itaconic acid, and acid anhydrides of the dicarboxylic acids. Of these, (meth) acrylic acid and itaconic acid are preferred from the viewpoint of particle stability, and methacrylic acid is more preferred. These can be used alone or in combination of two or more. Examples of the monomer (a-2) include unsaturated carboxylic acid esters such as methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, and 2-ethylhexyl (meth) acrylate, Examples thereof include aromatic monomers such as styrene and α-methylstyrene, (meth) acrylonitrile, vinyl acetate, N, N-dimethyl (meth) acrylamide and the like. Among these, unsaturated carboxylic acid esters are preferable. In particular, when the crosslinked polymer particles (ii) are hollow particles, 50% by mass or more of the monomer (a-2) is an unsaturated carboxylic acid ester. preferable. When the unsaturated carboxylic acid ester is less than 50% by mass of the monomer (a-2), the hollow particles may be distorted, and the hollow ratio may not be increased. Moreover, crosslinkable monomers, such as a butadiene, isoprene, divinylbenzene, ethylene glycol di (meth) acrylate, can be used, The preferable compounding quantity is 0-5 mass% of the sum total of a 1st polymerizable monomer (a). Yes, and more preferably 0.2-2% by mass. When the ratio of the crosslinkable monomer is more than 50% by mass of the monomer (a), swelling with a volatile base in the production process of the hollow particles described below is not sufficient, and light scattering properties are lowered, which is not preferable.

  The blending amounts of the monomer (a-1) and the monomer (a-2) in the first polymerizable monomer (a) are 5 to 80% by mass of the monomer (a-1) and 20 to 95% by mass of the monomer (a-2). The monomer (a-1) is preferably 10 to 60% by mass and the monomer (a-2) is 40 to 90% by mass, and more preferably the monomer (a-1) is 20 to 50% by mass and the monomer (a-2). It is 50-80 mass%. When the proportion of the monomer (a-1) is less than 5% by mass, the swellability under a volatile base is not sufficient, and when used as an ink or a light scattering agent, whiteness and light scattering are insufficient. There are cases. When the proportion of the monomer (a-1) exceeds 80% by mass, the polymerization stability of the first polymer particles (i) decreases, and the polymer derived from the second polymerizable monomer (b) described later on the surface layer is uniformly distributed. Since it becomes difficult to coat and the particle shape becomes distorted, when used as an ink or a light scattering agent, the whiteness and light scattering properties may be insufficient.

  The method for emulsion polymerization of the first polymerizable monomer (a) in an aqueous medium is not particularly limited. For example, the monomers may be added and polymerized at once, or may be continuously added and polymerized. However, the latter is preferable in order to obtain particles having a uniform particle size with good stability. The first polymer particles (i) may be prepared by one-stage polymerization or by two-stage or more multi-stage polymerization. Further, the first polymerizable monomer (a) may be subjected to seed emulsion polymerization in the presence of the seed particles (i ′) for preparing the first polymer particles (i). In particular, as the seed particles (i ′), Those having an SP value (solubility parameter) close to those of the first polymerizable monomer (a) are preferable in order to stably obtain particles having a uniform particle diameter. Examples of the emulsifier include an anionic surfactant, a nonionic surfactant, a cationic surfactant, an amphoteric surfactant, and an organic suspension protective agent. And anionic surfactants, nonionic surfactants, and organic suspension protecting agents are preferred. An emulsifier having a radically polymerizable unsaturated bond in the molecule, that is, a reactive emulsifier may be used. These emulsifiers can be used alone or in combination of two or more.

  Examples of the anionic surfactant include rosin salts such as potassium rosinate and sodium rosinate, sodium oleate, potassium laurate, sodium laurate, sodium laurate, sodium stearate, potassium stearate, and the like. Examples thereof include salts, sulfate esters of aliphatic alcohols such as sodium lauryl sulfate, and alkylallyl sulfonic acids such as sodium dodecylbenzene sulfonate.

  Examples of nonionic surfactants include polyoxyalkylene alkyl esters, alkyl ethers, and alkylphenyl ethers. Moreover, the dispersing agent (C) shown by Formula (1) mentioned later can also be used as an emulsifier.

  Examples of organic suspension protection agents include hydrophilic synthetic polymer materials such as polyacrylic acid, polymethacrylic acid, polyvinyl sulfonic acid, polyvinyl alcohol, polyvinyl pyrrolidone and polyethylene glycol, natural hydrophilic high substances such as gelatin and water-soluble starch. Examples thereof include molecular substances and hydrophilic semi-synthetic polymer substances such as carboxymethyl cellulose.

  Examples of the reactive emulsifier include an emulsifier having an ethylenically unsaturated group as a radical reactive group, a polyoxyalkylene group, a sulfone group, a sulfuric acid group as a hydrophilic group, and an alkyl group as a hydrophobic group in one molecule. Examples of such commercially available reactive emulsifiers include “Latemul S-180A”, “Latemul PD-104” [manufactured by Kao Corporation], “Eleminol JS-2” [manufactured by Sanyo Kasei Co., Ltd.], “Aqualon HS-10 Anionic reactions such as “Aqualon BC-10”, “Aquaron KH-10” [Daiichi Kogyo Seiyaku Co., Ltd.], “Adekaria Soap SE-10N”, “Adekaria Soap SR-10” [Asahi Denka Kogyo Co., Ltd.] Nonionic reactive emulsifiers such as “Aqualon RS-20” [Daiichi Kogyo Seiyaku Co., Ltd.], “Adekaria Soap NE-20”, “Adekaria Soap NR-20” [Asahi Denka Kogyo Co., Ltd.] Can be mentioned.

  The polymerization of the monomer (a-1) and the monomer (a-2) is radical polymerization, and the polymerization is started by a predetermined polymerization initiator. Examples of the polymerization initiator include organic hydroperoxides represented by cumene hydroperoxide, diisopropylbenzene hydroperoxide, paramentane hydroperoxide, t-butyl hydroperoxide and the like, sugar-containing pyrophosphate prescription, sulfoxy Rate formulation, sugar-containing pyrophosphate formulation / sulfoxylate formulation mixed system formulation, redox initiator in combination with a reducing agent represented by formaldehyde resin formulation, persulfates such as potassium persulfate, ammonium persulfate, Azobisisobutyronitrile, benzoyl peroxide, lauroyl peroxide, etc. can be mentioned. Among them, persulfates such as potassium persulfate and ammonium persulfate in terms of particle stability and particle size uniformity, azobis Isobutyronitrile, benzo Peroxide is preferable. Moreover, a reducing agent can also be used in combination as needed.

  In the emulsion polymerization in the present embodiment, a polymerization chain transfer agent, a chelating agent, an inorganic electrolyte, and the like can be used as necessary. Specific examples of the polymerization chain transfer agent include octyl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan, n-hexadecyl mercaptan, n-tetradecyl mercaptan, t-tetradecyl mercaptan, n-octyl thioglycol. Mercaptans such as dimethyl xanthogen disulfide, diethyl xanthogen disulfide, diisopropyl xanthogen disulfide, etc .; Xanthogen disulfides such as tetramethyl thiuram disulfide, tetraethyl thiuram disulfide, tetrabutyl thiuram disulfide; chloroform, carbon tetrachloride, ethylene bromide Halogenated hydrocarbons such as pentaphenylethane, α-methylstyrene dimer and the like; and acrolein, Takurorein, allyl alcohol, 2-ethylhexyl thioglycolate, terpinolene, alpha-terpinene, .gamma.-terpinene, can be mentioned dipentene and the like. These may be used alone or in combination of two or more. Of these, mercaptans, α-methylstyrene dimer and the like are preferably used. Further, as the chelating agent, ethylenediaminetetraacetic acid, nitrilotriacetic acid, diethylenetriaminepentaacetic acid, hydroxyethylethylenediaminetriacetic acid and the like, and as the inorganic electrolyte, sodium carbonate, sodium bicarbonate, potassium carbonate, potassium bicarbonate, carbonate Ammonium, sodium sulfate, potassium sulfate, ammonium sulfate and the like are used.

  The polymerization temperature is preferably 5 to 120 ° C, more preferably 50 to 100 ° C. When the temperature is lower than 5 ° C., the reactivity of the unsaturated carboxylic acid is low and the particles may become unstable. When the temperature exceeds 120 ° C., the particles may become unstable.

  As an average particle diameter of the 1st polymer particle (i) obtained by the above, Preferably it is 0.1-2 micrometers, More preferably, it is 0.2-2 micrometers. Moreover, the weight average molecular weight of the obtained polymer becomes like this. Preferably it is 1,000-50,000, More preferably, it is 2,000-20,000.

(Preparation of dispersion of crosslinked polymer particles (ii))
In the present embodiment, after preparing the first polymer particles (i), in the presence of 5 to 1000 parts by mass of the first polymer particles (i), the crosslinkable radical polymerizable monomer (b-1) (hereinafter, 10-80% by mass of “monomer (b-1)”), 0-20% by mass of unsaturated carboxylic acid (b-2) (hereinafter sometimes referred to as “monomer (b-2)”), and The second polymerizable monomer comprising 0 to 90% by mass of another radical polymerizable monomer (b-3) copolymerizable with the monomer (b-1) (hereinafter sometimes referred to as “monomer (b-3)”) (B) Crosslink weight obtained by emulsion polymerization of 100 parts by mass in an aqueous solvent and coating the surface layer of the first polymer particles (i) with a shell layer containing the second polymer derived from the second polymerizable monomer (b). A dispersion of coalesced particles (ii) is prepared. At this time, when there is an unreacted second polymerizable monomer (b), it is preferable from the viewpoint of odor to further polymerize the unreacted second polymerizable monomer (b). The final concentration of the second polymerizable monomer (b) in the dispersion is preferably 3000 ppm or less, more preferably 1000 ppm or less, and particularly preferably 300 ppm or less.

  In order to sufficiently polymerize the unreacted second polymerizable monomer (b), a polymerization initiator, a polymerization initiation assistant, a reducing agent, or the like may be added. Examples of the polymerization initiator include organic hydroperoxides represented by cumene hydroperoxide, diisopropylbenzene hydroperoxide, paramentane hydroperoxide, t-butyl hydroperoxide and the like, sugar-containing pyrophosphate prescription, sulfoxy Rate formulation, sugar-containing pyrophosphate formulation / sulfoxylate formulation mixed system formulation, redox initiator in combination with a reducing agent represented by formaldehyde resin formulation, persulfates such as potassium persulfate, ammonium persulfate, Examples thereof include azobisisobutyronitrile, benzoyl peroxide, lauroyl peroxide, etc. Among them, a system combining t-butyl hydroperoxide and a formaldehyde resin has high reactivity. preferable.

  When the crosslinked polymer particles (ii) are hollow particles, the pH of the dispersion of the crosslinked polymer particles (ii) is adjusted to 7 or more with a volatile base such as ammonia or amine, and neutralized and swollen. The crosslinked hollow polymer particle aqueous dispersion (iii) is prepared by heating as necessary and further polymerizing the unreacted second polymerizable monomer (b).

  Since the polymer derived from the second polymerizable monomer (b) can penetrate a volatile base, the addition of the volatile base neutralizes the first polymer particle (i) component. Along with this, the first polymer particle (i) component absorbs water remarkably, and a core-shell shape (the first polymer particle (i) becomes the core and the polymer derived from the second polymerizable monomer (b) covers the outer periphery thereof. The crosslinked polymer particles (ii) formed in (shell layer) are hollow polymer particles having pores therein. In the aqueous dispersion, the generated particles contain water in the pores inside the particles. The temperature of the dispersion when the crosslinked polymer particles are neutralized and swollen depends on the amount of the unreacted second polymerizable monomer (b) in the shell layer of the core-shell crosslinked polymer particles (ii). The glass transition temperature (Tg) of the polymer constituting the shell of a typical hollow particle is preferred. If neutralized and swollen at a temperature higher than that, the core inside may break the shell and jump out, and the hollowness ratio may decrease.

  After neutralizing and swelling the core-shell polymer particles (ii), a new radical polymerizable monomer may be added and polymerized to form part of the shell of the hollow particles. Is preferable. The monomer used in this case is preferably a monomer such as the monomer (b-1), the monomer (b-2), or the monomer (b-3), and particularly preferably the monomer (b-1). In that case, it is preferred to add the initiator system described above.

  In the present embodiment, as the monomer (b-1), divinylbenzene, trivinylbenzene, dicyclopentadiene, butadiene, isoprene, allyl glycidyl ether, glycidyl (meth) acrylate, ethylene glycol dimethacrylate, trimethylolpropane tri ( Crosslinkable radically polymerizable monomers such as (meth) acrylate, pentaerythritol tri (meth) acrylate and dipentaerythritol hexa (meth) acrylate can be used. By producing cross-linked polymer particles using the cross-linkable radical polymerizable monomer (b-1), the bonding force between the particles is reduced, the particles are less likely to aggregate, and also when the particles are aggregated. It becomes easy to redisperse. In addition, it has excellent resistance to heat, mechanical stress, solvents and chemicals. In particular, divinylbenzene and ethylene glycol di (meth) acrylate are preferable, and divinylbenzene is most preferable. The compounding amount of the monomer (b-1) is 10 to 80% by mass of the total amount of the monomer (b), preferably 10 to 60% by mass, and more preferably 10 to 50% by mass. When the crosslinkable radical polymerizable monomer (b-1) exceeds 80% by mass, the whiteness and light scattering properties may be insufficient when used as an ink or a light scattering agent.

  As the monomer (b-2), the same unsaturated carboxylic acid as the example of the monomer (a-1) described above can be used, and (meth) acrylic acid is particularly preferable from the viewpoint of particle stability. Itaconic acid and the like are preferable.

  Examples of the monomer (b-3) include monoethylenic aromatic compounds such as styrene and α-methylstyrene, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, Use of non-crosslinkable radically polymerizable monomers such as unsaturated carboxylic acid esters such as butyl (meth) acrylate and 2-ethylhexyl (meth) acrylate, (meth) acrylonitrile, vinyl acetate and N, N-dimethyl (meth) acrylamide Can do. Among these, monoethylenic aromatic compounds such as styrene are preferable.

  The blending amounts of the monomer (b-2) and the monomer (b-3) in the second polymerizable monomer (b) are 0 to 20% by mass of the monomer (b-2) and 0 to 90% by mass of the monomer (b-3). The monomer (b-2) is 0.1 to 10% by mass and the monomer (b-3) is 30 to 89.9% by mass, more preferably the monomer (b-2) is 0.2 to 5% by mass and It is 45-89.8 mass% of monomers (b-3). When the proportion of the monomer (b-1) exceeds 20% by mass, the polymerization stability is remarkably deteriorated, and the polymer particles after the volatile base treatment and the heat treatment are deformed and the porosity is lowered. When used as an ink or a light scattering agent, whiteness and light scattering properties may be insufficient.

  In the present embodiment, as described above, the first polymer particles (i) are 5 to 1000 parts by mass, preferably 7 to 100 parts by mass, and more preferably 10 to 50 parts by mass in the presence of the second polymer particles (i). A crosslinked polymer obtained by emulsion polymerization of 100 parts by mass of the polymerizable monomer (b) and coating the surface layer of the first polymer particles (i) with a shell layer containing the second polymer derived from the second polymerizable monomer (b). Prepare particles (ii). If the first polymer particle (i) is less than 5 parts by mass, the particle size of the crosslinked polymer particles becomes small, so that the dispersibility is inferior. If it exceeds 1000 parts by mass, the polymerization stability becomes poor and the crosslinked polymer Therefore, the hardness of the particles decreases and the particles tend to aggregate.

  There is no restriction | limiting in particular as a method of emulsion-polymerizing a 2nd polymerizable monomer (b), The same method as the example shown by the 1st polymer particle (i) mentioned above can be used. In this case, in order to complete the coating structure of the shell, it is preferable that a part or all of the second polymerizable monomer (b) is initially charged and emulsion polymerized by batch charging. At that time, the mass ratio of the second polymerizable monomer (b) and the first polymer particles (i) to be emulsion-polymerized first by batch charging is preferably 10: 1 to 1:10, more preferably 5: 1 to 1: 5. Is particularly preferred. When the ratio exceeds 10: 1, a problem occurs in polymerization stability. If it is less than 1:10, the coating of the first polymer particles (i) is insufficient, the hardness of the particles decreases, and the particles tend to aggregate. Further, the second polymerizable monomer (b) to be initially emulsion-polymerized by batch charging is particularly preferably a monoethylenic aromatic compound such as styrene and an unsaturated carboxylic acid ester such as methyl (meth) acrylate.

  The average particle diameter of the primary particles of the crosslinked polymer particles (ii) obtained as described above is usually 0.01 to 100 μm, preferably 0.02 to 50 μm, more preferably 0.05 to 20 μm, most preferably 0.00. 1 μm to 10 μm. If it is less than 0.01 μm, the dispersibility is inferior, and the cross-linked polymer particles exceeding 100 μm do not have the problem of dispersibility, which is the subject of the present invention.

(Preparation of crosslinked polymer particle powder)
In the present embodiment, after the dispersion of the crosslinked polymer particles (ii) is prepared, the dispersion represented by the following formula (2) with respect to 100 parts by mass of the dispersion of the obtained crosslinked polymer particles (ii). 1 to 100 parts by mass of an agent is added and then dried to obtain a crosslinked polymer particle powder.
^{T 1 O- (RO) n (} EO) m-T 2 ... (2)
(T ¹ is a hydrogen atom, an alkyl group having 1 to 18 carbon atoms or an alkenyl group having 2 to 18 carbon atoms, and T ² is a hydrogen atom, a sulfonic acid (salt) group, a carboxylic acid (salt) group, phosphoric acid ( Salt) group, amino group or ammonium group, RO is an oxyalkylene group having 3 to 18 carbon atoms, EO represents an oxyethylene group, n is an integer of 1 to 50, and m is an integer of 0 to 200. Yes, n RO groups are of the same type or different types, and n RO groups and m EO groups are block bonds or random bonds.)

  In the case where n RO groups and m EO groups are block bonds, the arrangement order of RO groups and EO groups may be any.

The dispersant represented by the above formula (2) should be the same as the dispersant represented by the above formula (1) used in one embodiment of the above-mentioned crosslinked polymer particle powder of the present invention. Can do. That is, the T ^1, and more preferably an alkyl group or an alkenyl group having 3 to 12 carbon atoms, particularly preferably an alkenyl group having 3 to 7 carbon atoms. T ² is more preferably a hydrogen atom or a sulfonate group, and particularly preferably an ammonium sulfonate group. And as a specific example of a dispersing agent, Latmul PD-104 made by Kao Corporation is particularly preferable under the trade name.

  There is no particular limitation on the method of drying and pulverizing the dispersion obtained by adding the dispersant represented by the above formula (2) to the dispersion of the crosslinked polymer particles (ii). For example, a spray drying method is available. (135 to 155 ° C), a tray drying method (50 to 70 ° C) using a hot air dryer, a fluidized bed drying method (normal temperature to 70 ° C), and the like.

  Next, an embodiment of a non-aqueous crosslinked polymer particle dispersion obtained by dispersing the crosslinked polymer particle powder of the present invention in an organic solvent will be described.

  The non-aqueous crosslinked polymer particle dispersion of the present embodiment is such that the crosslinked polymer particles and the dispersant represented by the above formula (1) are dispersed in an organic solvent, and 100 parts by mass of the crosslinked polymer particles. The organic solvent is contained in an amount of 50 to 10,000 parts by mass.

  Examples of the organic solvent used in the non-aqueous crosslinked polymer particle dispersion of the present embodiment include alcohols such as methanol, ethanol and isopropanol; ethers such as dioxane, tetrahydrofuran and 1,3-dioxolane; acetone and methyl ethyl ketone. , Ketones such as diacetone alcohol and γ-butyrolactone; esters such as ethylene glycol monomethyl ether acetate and ethyl lactate; methyl cellosolve, ethyl cellosolve, butyl cellosolve, ethylene glycol isopropyl ether, ethylene glycol dimethyl ether, ethylene glycol t-butyl ether, 3 -Methyl 3-methoxybutanol, 3-methoxybutanol, methyl carbitol, ethyl carbitol, butyl carbitol, propylene glycol Monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol monobutyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, tripropylene glycol Glycol ethers such as monomethyl ether; Amides such as N-dimethylformamide, N-methylacetamide, N, N-dimethylacetamide, N-methylpyrrolidone, morpholine, N-methylmorpholine, N, N-dimethylformamide, monoethanolamine -Amines etc. are mentioned. Among these, at least one selected from the group consisting of water-soluble amines, water-soluble glycol ethers, water-soluble ketones and water-soluble esters is particularly preferable. By using such an organic solvent, the crosslinked polymer particles can be effectively dispersed, and the safety and coating properties are excellent.

  Other examples of the organic solvent include straight chain aliphatic hydrocarbons, branched aliphatic hydrocarbons, and cyclic aliphatic hydrocarbons having 6 to 12 carbon atoms; halogenated hydrocarbons having 1 to 8 carbon atoms; 2-heptanone, 3 -Ketones such as heptanone, 4-heptanone, cyclohexanone; lactate esters such as n-propyl lactate and isopropyl lactate; ethyl acetate, n-propyl acetate, isopropyl acetate, n-butyl acetate, isobutyl acetate, n-amyl acetate, Aliphatic carboxylic acid esters such as isoamyl acetate, isopropyl propionate, n-butyl propionate, isobutyl propionate; methyl 3-methoxypropionate, ethyl 3-methoxypropionate, methyl 3-ethoxypropionate, 3-ethoxypropionate S, such as ethyl acid, methyl pyruvate, ethyl pyruvate Ethylene glycol monoalkyl ether acetates such as ethylene glycol monoethyl ether acetate and ethylene glycol monobutyl ether acetate; propylene glycol monoalkyl ethers such as propylene glycol monobutyl ether; propylene glycol monomethyl ether acetate and propylene glycol monoethyl ether acetate Propylene glycol monoalkyl ether acetates such as propylene glycol monopropyl ether acetate and propylene glycol monobutyl ether acetate; propylene such as propylene glycol dimethyl ether, propylene glycol diethyl ether, propylene glycol dipropyl ether and propylene glycol dibutyl ether Glycol dialkyl ethers; alcohols such as n- hexanol.

  Thus, by blending the crosslinked polymer particle powder in an organic solvent to form a non-aqueous crosslinked polymer particle dispersion, it is possible to facilitate blending of ink, light scattering coating material, and the like.

  As a method for producing the non-aqueous crosslinked polymer particle dispersion of the present embodiment, first, a crosslinked polymer particle powder is produced by the above-described method for producing a crosslinked polymer particle powder. And it is obtained by adding the obtained crosslinked polymer particle powder in an organic solvent (redispersion method). Further, in the above-mentioned method for producing a crosslinked polymer particle powder, after preparing a dispersion of crosslinked polymer particles (ii), an organic solvent may be added without drying, and then water may be removed (solvent replacement). Law). A method of replacing the aqueous solvent with an organic solvent may also be used.

  As a method for removing water in the above “solvent replacement method”, a known method can be used. For example, when the organic solvent has a boiling point higher than that of water, the following method can be mentioned.

(Evaporator type)
A method of distilling off water by heating or stirring at room temperature while blowing a gas such as air or nitrogen into the reaction vessel under reduced pressure or normal pressure. As a specific apparatus, a four-necked flask used for polymerization in the laboratory and a reactor used for polymerization in the laboratory can be used as they are for the polymerization.

(Centrifugal thin film type)
A method of rotating the conical heat transfer surface, thinning the liquid by centrifugal force, and evaporating the water. As a specific apparatus, an evaporator can be used in the laboratory, and industrially, “Evapol” manufactured by Okawara Seisakusho, “centrifugal molecular distillation apparatus” manufactured by Nippon Vehicle Co., Ltd. or the like can be used.

(External circulation spray type)
A method of evaporating water by flowing a treatment liquid and a heating medium alternately on the surface of corrugated plates. As a specific apparatus, “Bubbles” manufactured by Nisso Engineering Co., Ltd. can be used.

(Flowing thin film type)
A method of evaporating water while the treatment liquid flows down from the top of the heating tube group in a thin film.

(Stirring thin film type)
A method of forcibly thinning the treatment liquid with a stirring blade installed in a cylindrical heating tube and evaporating water. Specific equipment includes “Wiperen” and “Exeva” manufactured by Shinko Pantech.

  Regardless of the boiling point of the organic solvent, for example, water is removed using a dehydrating agent such as molecular sieve, calcium sulfate, or phosphorus pentoxide, or the organic solvent is added while concentrating using a ceramic ultrafiltration membrane. There are ways to go.

  Next, an embodiment of the ink of the present invention containing the crosslinked polymer particle powder of the present invention will be described.

  The ink of the present invention can be produced by dispersing the crosslinked polymer particle powder of the present invention in a medium. The ink of the present embodiment can be used as an ink for ink jet recording, a writing instrument such as a general fountain pen, a ballpoint pen, and a sign pen.

  As described above, when the crosslinked polymer particle powder of the present invention is contained in the ink, the solid particle is an ink having excellent print quality such as drying property and sharpness of the outline, and the hollow particle is stored. The resulting white ink has excellent stability. Further, since the crosslinked polymer particle powder is a powder, the degree of freedom of ink blending is increased. In addition, since the crosslinked polymer particle powder of the present invention has few foreign matters, the ink is less likely to clog the nozzle when used as an ink for ink jet recording.

  The content ratio of the crosslinked polymer particles in the ink of the present embodiment is usually 0.1 to 50% by mass, preferably 1 to 30% by mass in terms of solid content in the whole ink. When this content is less than 0.1% by mass, the effect of the crosslinked polymer particles is reduced, and when it exceeds 50% by mass, the storage stability as an ink may be reduced.

  In addition to the crosslinked polymer particles and medium of the present invention, the ink of the present embodiment can also contain a binder, a dye, a pigment, and a known additive.

  When the cross-linked polymer particles constituting the cross-linked polymer particle powder of the present invention are hollow particles, they have high whiteness in appearance, and therefore when they are contained in the ink of the present embodiment, they are concealable. Acts as a high white pigment. And it will have the whiteness which was excellent by making it contain in the ink as all or one part of a pigment.

  Since the ink of the present embodiment contains crosslinked polymer particles, the crosslinked polymer particles are not dissolved or deformed even when, for example, an organic solvent is contacted. Therefore, when the crosslinked polymer particle is a hollow particle, there is an advantage that the whiteness is maintained stably as a result.

  In the ink of the present embodiment, the binder to be blended as necessary is not particularly limited, and for example, styrene / acrylic acid copolymer resin, polyvinyl pyrrolidone resin, urethane resin, acrylic resin, styrene / maleic resin. Examples thereof include acid copolymer resins, α-olefin / maleic acid copolymer resins, vinyl acetate resins, polyvinyl butyral resins, sulfonated isoprene / styrene copolymer resins, and the like. The content ratio of the binder in the ink is usually 1 to 20% by mass, preferably 2 to 10% by mass. When this ratio is less than 1% by mass, sufficient color development may not be obtained, and when it exceeds 20% by mass, the storage stability as an ink may be lowered.

  In the ink of the present invention, the dye blended as necessary is not particularly limited, and examples thereof include an aqueous dye, an oily dye, a disperse dye, a direct dye, an acid dye, and a basic dye. .

  Examples of the disperse dye include C.I. I. Disperse Yellow 5, 42, 54, 64, 79, 82, 83, 93, 100, 122, 124, 126, 160, 184, 199, 204 and 224, C.I. I. Disperse Orange 13, 29, 31, 33, 49, 54, 55, 66, 73, 118 and 163, C.I. I. Disperse Red 60,72,73,86,88,91,92,93,111,126,127,134,135,145,164,177,181,204,206,207,239,240,283,323 , 343, and 362, C.I. I. Disperse Blue 56, 60, 73, 87, 113, 128, 143, 148, 154, 158, 197, 198, 201, 257, 266, 287, 354, and 365, and C.I. I. Disperse Green 9 etc. can be mentioned.

  Examples of the oil dye include C.I. I. Solvent Black 3, 7, 27, 29, and 34, C.I. I. Solvent Yellow 14, 16, 19, 29, 56, 82 and 162, C.I. I. Solvent Red 1, 3, 8, 18, 24, 27, 43, 51 and 72, C.I. I. Solvent Blue 2, 11, 70 etc. can be mentioned.

  Examples of the direct dye include C.I. I. Direct black 19 etc. can be mentioned.

  Examples of the acid dye include C.I. I. Acid Black 2 and 12, C.I. I. Acid Yellow 23, C.I. I. Acid Red 51, 87 and 92, C.I. I. Examples include Acid Blue 1, 9 and 74.

  Examples of the basic dye include C.I. I. Basic Yellow 2 and 11, C.I. I. Basic Red 1 and 13, C.I. I. Basic blue 5, 7, 9, 26, etc. can be mentioned.

  Although the said dye may be used individually by 1 type, it is also possible to use 2 or more types together.

Examples of the pigment used in the ink of the present invention as necessary include insoluble azo pigments, condensed azo pigments, azo lakes, chelate azo pigments and other azo pigments, phthalocyanine pigments, perylene and perinone pigments, anthraquinone pigments, quinacridone pigments, dioxazines. Polycyclic pigments such as pigments, thioindigo pigments, isoindolinone pigments, quinophthalone pigments, organic pigments such as dye lakes, nitro pigments, nitroso pigments, aniline black, fluorescent pigments, titanium oxides, iron oxides, carbon blacks, etc. Can be mentioned.
Although the said pigment may be used individually by 1 type, it is also possible to use 2 or more types together.

  The dyes and pigments can be used alone or in combination of two kinds. The concentration of the dye or pigment contained in the ink of the present invention is usually 1 to 30% by mass, preferably 1.5 to 25% by mass. When the concentration of the dye or pigment is less than 1% by mass, sufficient color development may not be obtained, and when it exceeds 30% by mass, aggregates may be formed in the ink.

  When oily dyes, disperse dyes or pigments are used, it is preferable to disperse these in advance in a medium such as water. For the preparation of this aqueous dispersion, a bead mill, sand mill, coreless mixer is used. It can be dispersed using a known disperser such as a paint shaker, an ultrasonic disperser, or a high-pressure homogenizer. The pigment aqueous dispersion can also be obtained as a commercial product as an industrial product.

  As specific examples of the mixing method of these ink raw materials, an aqueous dispersion of a dye or pigment or an aqueous dispersion of a dye or pigment is stirred, and then an aqueous dispersion of a binder and hollow polymer particles is added. The method of putting additives, such as, can be mentioned. When an oily dye, disperse dye or pigment is dispersed in water in advance, it is preferable to add additives such as a binder, a wetting agent and an antifoaming agent in this dispersion step. Ink may be obtained.

  Known additives that can be added to the ink of the present embodiment include, for example, wetting agents such as polyhydric alcohols, surface tension adjusting agents such as dispersants, antifoaming agents, various surfactants, chelating agents, Examples thereof include an oxygen absorbent, a water-soluble polymer, a polymer emulsion, a pH adjuster, an antiseptic / antifungal agent, a rust preventive, an ultraviolet absorbent, and an infrared absorbent.

  Examples of the wetting agent include glycols such as ethylene glycol, propylene glycol, and diethylene glycol, polyhydric alcohol ethers such as glycerin, diethylene glycol monobutyl ether, triethylene glycol monobutyl ether, and carbitols, acetates, thiodiglycol, N -Nitrogen-containing compounds such as methyl-2-pyrrolidone and triethanolamine.

  Dispersants include anionic surfactants such as fatty acid salts and alkyl sulfonates, cationic surfactants such as aliphatic amines and quaternary ammonium salts, amphoteric surfactants such as betaine type compounds, polyoxyethylene, and the like. Nonionic surfactants such as fatty acid ester type compounds, cellulosic polymer materials, lignin sulfonates, polyacrylates, styrene / acrylic acid copolymer salts, styrene / maleic acid copolymer salts, naphthalene Formalin condensates of sulfonic acid, polyvinyl alcohol, polyethylene glycol and the like can be mentioned.

  In the production of ink, it is preferable to provide a filtration step. In the filtration process, stainless steel mesh, nylon mesh, membrane filter, pleated filter, depth filter, ceramic membrane filter, etc. are used as the filter medium, and batch type, continuous type, circulation type, etc. are preferably used as the filtration method. it can. Industrially, it is particularly preferable to use a circulation system using a depth filter.

  The ink of the present embodiment preferably satisfies a specific physical property. For example, an ink used for an ink jet system needs to have an appropriate viscosity and surface tension. The viscosity of the inkjet recording ink is usually 0.7 to 15 mPa · s, preferably 1 to 10 mPa · s at 25 ° C., and the surface tension of the ink is usually 20 to 70 dyn / cm at 25 ° C., preferably It is 25-60 dyn / cm, More preferably, it is 30-40 dyn / cm.

  Next, an embodiment of the light scattering material of the present invention will be described.

  The light scattering material of the present embodiment is made of the crosslinked polymer particle powder of the present invention, and is disposed on the surface of an optical article or paper, for example, so as to have a function of scattering incident light. Is.

  The light scattering material of the present embodiment may be used as an optical article by being disposed on the surface of a transparent substrate with a binder or the like in a powder state, and the light scattering material of the present embodiment may be organic. After preparing a liquid light scattering agent by dispersing in a solvent or the like, the liquid light scattering agent may be applied to a transparent substrate or the like, dried, and formed into a film. When the crosslinked polymer particle powder of the present invention is used as the light scattering material of the present invention, the crosslinked polymer particle powder may be solid particles, but is preferably hollow particles. This is because the light scattering property is improved and the light scattering material becomes more excellent by being a hollow particle.

  When the light scattering material of the present embodiment is dispersed in an organic solvent, as the organic solvent used for dispersion, the organic solvent used in the above-described non-aqueous crosslinked polymer particle dispersion of the present invention may be used. it can. Further, the mixing ratio of the light scattering material and the organic solvent can also be made the same as in the case of the non-aqueous crosslinked polymer particle dispersion of the present invention described above.

  When the light scattering material of the present embodiment is disposed on a transparent base material to form an optical article, as a transparent base material, in addition to inorganic glass, polyester resin including polyethylene terephthalate, polyethylene naphthalate, polycarbonate resin, Various transparent plastic plates such as acrylic resin, styryl resin, arylate resin, norbornene resin, and triacetyl cellulose, films, and the like can be used. Preferably, inorganic glass, polyethylene terephthalate resin, polycarbonate resin, acrylic resin, or triacetyl cellulose resin is used.

  As a method for disposing the light scattering material of the present embodiment on the transparent substrate, when the light scattering material is dispersed in an organic solvent or the like, a roll coater, a flow coater, a centrifugal coater, an ultrasonic coater, Examples of the method include coating using a micro) gravure coater or the like, dip coating, flow coating, spraying, a screen process, and the like. Preferred are coating using a roll coater and (micro) gravure coater.

  Further, as a method of disposing the light scattering material on the transparent base material in a powder state, it can be disposed as a powder coating by an electrostatic powder coating machine or the like.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples. In the following description, “parts” and “%” indicate parts by mass and mass% unless otherwise specified.

(Evaluation of dispersibility in organic solvents (solvent dispersibility))
10 g of the particle powder was dispersed in 90 g of triethylene glycol monobutyl ether using an ultrasonic disperser, which was sealed in a glass tube with a lid and allowed to stand at 25 ° C. for 24 hours. This was visually observed, ◯ when there was no change, △ when no change was observed but a change in viscosity was observed, and x when separation or significant thickening was observed.

(Evaluation of nozzle clogging in inkjet)
40 g of the dispersion used for the evaluation of dispersibility in the organic solvent (including 4 g of particle powder and 36 g of triethylene glycol monobutyl ether), 1 g of glycerin and 59 g of ion-exchanged water were mixed, and the resulting dispersion was used. Prepare a water-based inkjet ink by filtering with a 5 micron filter, and print using this water-based ink with an inkjet printer “MC2000” (manufactured by Seiko Epson Corporation). The case where clogging occurred in the nozzles but returned by head cleaning was indicated by Δ, and the case where nozzles were clogged during printing and did not return even after head cleaning was indicated by ×.

(Evaluation of dispersibility in resin (resin dispersibility))
100 parts of RB810 (syndiotactic 1,2-polybutadiene) manufactured by JSR Co. was wound around a roll at 85 ° C., and then 5 parts of particle powder was blended, cut out for 3 minutes, and taken out. This was pressed with a heating press to obtain a 1 mm thick sheet. The obtained sheet was visually observed, and the case where no aggregation of particles was observed and the particles were uniformly dispersed was evaluated as ◯, and the case where aggregation was observed was evaluated as x.

(Production Example 1: Production of crosslinked polymer particles using a monomer other than divinylbenzene)
A 2 L flask containing 95 parts of styrene, 5 parts of methacrylic acid, 10 parts of t-dodecyl mercaptan, 5 parts of α-methylstyrene dimer, 0.8 part of sodium dodecylbenzenesulfonate, 1.0 part of potassium persulfate and 200 parts of water. The mixture was heated to 80 ° C. in nitrogen gas while stirring and subjected to emulsion polymerization for 6 hours. Thereby, polymer particles having a polymerization yield of 98%, an average particle diameter of 150 nm, and a weight average molecular weight of 3200 were obtained. Obtained. 10 parts of this polymer particle (in terms of solid content), 0.3 part of sodium lauryl sulfate, 0.5 part of potassium persulfate, and 400 parts of water were charged into this, 5 parts of ethylene glycol dimethacrylate, acrylic A monomer composition consisting of a mixture of 5 parts of acid and 90 parts of methyl methacrylate was added and stirred at 30 ° C. for 1 hour, followed by emulsion polymerization while stirring at 70 ° C. for 5 hours to complete the polymerization. As a result of filtration through a stainless steel mesh net, an aqueous dispersion (A-1) of spherical crosslinked polymer particles having a solid content of 20.6% and an average particle size of 320 nm was obtained.

(Production Example 2: Production of crosslinked polymer particles with divinylbenzene)
A 2 L flask containing 95 parts of styrene, 5 parts of methacrylic acid, 10 parts of t-dodecyl mercaptan, 5 parts of α-methylstyrene dimer, 0.8 part of sodium dodecylbenzenesulfonate, 1.0 part of potassium persulfate and 200 parts of water. The mixture was heated to 80 ° C. in nitrogen gas while stirring and subjected to emulsion polymerization for 6 hours. Thereby, polymer particles having a polymerization yield of 98%, an average particle diameter of 150 nm, and a weight average molecular weight of 3200 were obtained. Obtained. 10 parts of the polymer particles (in terms of solid content), 0.3 part of sodium lauryl sulfate, 0.5 part of potassium persulfate, and 400 parts of water were charged, and 95 parts of divinylbenzene (purity 81%) was added thereto. And a monomer composition consisting of a mixture of 5 parts of acrylic acid, stirred at 30 ° C. for 1 hour, and then emulsion polymerization while stirring at 70 ° C. for 5 hours to complete the polymerization. As a result, an aqueous dispersion (A-2) of spherical crosslinked polymer particles having a solid content of 20.1% and an average particle diameter of 300 nm was obtained.

(Production Example 3: Production of hollow particles)
80 parts of styrene, 5 parts of methacrylic acid, 15 parts of methyl methacrylate, 10 parts of t-dodecyl mercaptan, 5 parts of α-methylstyrene dimer, 0.8 part of sodium dodecylbenzenesulfonate, 1.0 part of potassium persulfate and water 200 Part was placed in a 2 L flask, heated to 80 ° C. in nitrogen gas with stirring, and subjected to emulsion polymerization for 6 hours, whereby a polymerization yield of 98%, an average particle diameter of 150 nm, and a weight average molecular weight 3500 polymer particles were obtained. 10 parts of this polymer particle (in terms of solid content), 0.3 part of sodium lauryl sulfate, 0.5 part of potassium persulfate, and 400 parts of water are charged, and 20 parts of divinylbenzene (purity 55%) are added thereto. A monomer composition consisting of a mixture of 5 parts of acrylic acid and 75 parts of methyl methacrylate was added and stirred at 30 ° C. for 1 hour, and further emulsion polymerization was carried out at 70 ° C. for 5 hours to complete the polymerization. As a result of filtration through a 200-mesh stainless steel wire mesh, hollow spherical crosslinked hollow polymer particles having a single pore having a solid content of 20.5%, an average particle diameter of 350 nm, an inner diameter of 200 nm, and a volume porosity of 19% are obtained. An aqueous dispersion (A-3) was obtained.

(Comparative Production Example 1: Production of non-crosslinked polymer particles)
A 2 L flask containing 95 parts of styrene, 5 parts of methacrylic acid, 10 parts of t-dodecyl mercaptan, 5 parts of α-methylstyrene dimer, 0.8 part of sodium dodecylbenzenesulfonate, 1.0 part of potassium persulfate and 200 parts of water. The mixture was heated to 80 ° C. in nitrogen gas while stirring and subjected to emulsion polymerization for 6 hours. Thereby, polymer particles having a polymerization yield of 98%, an average particle diameter of 150 nm, and a weight average molecular weight of 3200 were obtained. Obtained. 10 parts of this polymer particle (in terms of solid content), 0.3 part of sodium lauryl sulfate, 0.5 part of potassium persulfate, and 400 parts of water were charged into this, 5 parts of acrylic acid, and methyl methacrylate. A monomer composition comprising 95 parts of a mixture was added and stirred at 30 ° C. for 1 hour, followed by emulsion polymerization while stirring at 70 ° C. for 5 hours to complete the polymerization and filtered through a 200 mesh stainless steel wire mesh. An aqueous dispersion (A′-1) of spherical non-crosslinked polymer particles having a solid content of 20.5% and an average particle diameter of 320 nm was obtained.

(Example 1)
In 100 parts (solid content) of the aqueous dispersion (A-1) of the crosslinked polymer particles obtained in Production Example 1, n = 7, m = 10, T in the dispersant represented by the above formula (1) After adding 15 parts of Kao Latemul PD-104 where ¹ is an alkenyl group having 5 carbon atoms, T ² is an ammonium sulfonate group, and RO is an oxyalkylene group having 4 carbon atoms, a spray dryer manufactured by Okawara Chemical Industries Co., Ltd. (Pilot series L-12 type) was dried to obtain a crosslinked polymer particle powder (B-1). The evaluation results of the obtained crosslinked polymer particle powder (B-1) are shown in Table 1.

(Examples 2 and 3 and Comparative Example 1)
Particle powders (B-2), (B-3) and (B) are the same as in Example 1, except that the aqueous dispersions of particles obtained in Production Examples 2 and 3 and Comparative Production Example 1 are used. '-1) was obtained. The evaluation results of the obtained particle powder are shown in Table 1.

(Comparative Example 2)
In 100 parts (solid content) of the aqueous dispersion (A-1) of the crosslinked polymer particles obtained in Production Example 1, n = which is outside the scope of the present invention in the dispersant represented by the above formula (1) 0, m = 20, T ¹ is alkyl group of 12 carbon atoms, after the T ² was added 15 parts of Kao Corporation Emulgen 147 is a hydrogen atom, Ohkawara Kakohki Co. spray dryer (pilot Series L-12 type ) To obtain a crosslinked polymer particle powder (B ″ -1). The evaluation results of the obtained crosslinked polymer particle powder (B ″ -1) are shown in Table 1. In Table 1, EDMA indicates ethylene glycol dimethacrylate, and DVB indicates divinylbenzene.

  In Examples 2 and 3, since the crosslinked polymer particle powder used divinylbenzene as a crosslinking monomer and also used PD-104 represented by the above formula (1) as a dispersant, solvent dispersibility, nozzle clogging and All of the resin dispersibility showed extremely good results. In Example 1, since EDMA was used as a crosslinking monomer, the solvent dispersibility and nozzle clogging were slightly inferior to those in Examples 2 and 3, but the results were good overall. Since Comparative Example 1 uses Emulgen 147 as a dispersant, the evaluation is bad for all of the solvent dispersibility, nozzle clogging and resin dispersibility. Since Comparative Example 2 does not use a cross-linking monomer (not a cross-linked polymer), all of the solvent dispersibility, nozzle clogging, and resin dispersibility are evaluated as “x”.

  The crosslinked polymer particle powder of the present invention can be used as a light scattering material or the like used for the production of an optical article having a surface that scatters incident light and the coating of the surface of paper, fiber, leather and the like. In addition, the ink added to the ink and used as a pigment, the ink added with the crosslinked polymer particle powder of the present invention is an ink for ink-jet recording ink, a writing instrument such as a general fountain pen, ballpoint pen, sign pen, etc. Etc. can be used.

Claims (7)

A crosslinked polymer particle powder containing 100 parts by mass of a crosslinked polymer particle and 1 to 100 parts by mass of a dispersant represented by the following formula (1).
^{T 1 O- (RO) n (} EO) m-T 2 ... (1)
(T ¹ is a hydrogen atom, an alkyl group having 1 to 18 carbon atoms or an alkenyl group having 2 to 18 carbon atoms, and T ² is a hydrogen atom, a sulfonic acid (salt) group, a carboxylic acid (salt) group, phosphoric acid ( Salt) group, amino group or ammonium group, RO is an oxyalkylene group having 3 to 18 carbon atoms, EO represents an oxyethylene group, n is an integer of 1 to 50, and m is an integer of 0 to 200. Yes, n RO groups are of the same type or different types, and n RO groups and m EO groups are block bonds or random bonds.)   The crosslinked polymer particle powder according to claim 1, wherein the crosslinked polymer particles are divinylbenzene copolymer particles.   The crosslinked polymer particle powder according to claim 1 or 2, wherein the crosslinked polymer particles are hollow particles.   A non-aqueous crosslinked polymer particle dispersion obtained by dispersing the crosslinked polymer particle powder according to any one of claims 1 to 3 in an organic solvent.   An ink containing the crosslinked polymer particle powder according to any one of claims 1 to 3.   A light scattering material comprising the crosslinked polymer particle powder according to claim 1. A step of emulsion-polymerizing a polymerizable monomer containing a crosslinkable radically polymerizable monomer in the presence of seed particles (i) in an aqueous medium to obtain a dispersion of crosslinked polymer particles (ii);
1 to 100 parts by mass of a dispersant represented by the following formula (2) is added to 100 parts by mass of the obtained dispersion of the crosslinked polymer particles (ii), and then dried to obtain a crosslinked polymer particle powder. Obtaining a step;
A method for producing a crosslinked polymer particle powder comprising:
^{T 1 O- (RO) n (} EO) m-T 2 ... (2)
(T ¹ is a hydrogen atom, an alkyl group having 1 to 18 carbon atoms or an alkenyl group having 2 to 18 carbon atoms, and T ² is a hydrogen atom, a sulfonic acid (salt) group, a carboxylic acid (salt) group, phosphoric acid ( Salt) group, amino group or ammonium group, RO is an oxyalkylene group having 3 to 18 carbon atoms, EO represents an oxyethylene group, n is an integer of 1 to 50, and m is an integer of 0 to 200. Yes, n RO groups are of the same type or different types, and n RO groups and m EO groups are block bonds or random bonds.)