Abstract: A process for producing an article by three-dimensional printing includes applying a 1,1-di-activated vinyl compound-containing liquid binder over a predetermined area of a layer of solid particles. The liquid binder infiltrates gaps between the solid particles to form a first cross-sectional layer of an article, and the 1,1-di-activated vinyl compound reacts to solidify the liquid binder and bind the solid particles in the first cross-sectional layer of the article. Also provided is an article produced by the three-dimensional printing process, set forth herein.

Abstract: A one part, storage stable polymerizable formulation is provided that includes an ethenically unsaturated polymerizable compound intermixed with a free radical polymerization initiator and an organic solvent. The organic solvent provides storage stability and upon evaporation of the solvent, the rate of polymerization of the compound accelerates independent of addition of a second part. The formulation includes at least 30 total weight percent solids upon cure. Optional additives to the formulation include at least one of a cure accelerator, a filler, a plasticizer, a colorant, and a cure inhibitor. A process for forming a polymerized coating on an article involves the application of this formulation to the substrate of an article and allowing sufficient time for the solvent to evaporate to form the polymerized coating on the article. The substrate of the article forms a corrosion barrier even without prior removal of a native corrosion layer on a surface of the substrate of the article.

Abstract: Ink and coating compositions, printing and coating processes, and printed and coated substrates utilizing a polymerizable composition comprising one or more di-activated vinyl compounds, with the proviso that said a di-activated vinyl compound is not a cyanoacrylate. Exemplary compositions include methylene malonates, methylene ?-ketoesters, methylene ?-diketones, dialkyl disubstituted vinyls, and dihaloalkyl disubstituted vinyls. Exemplary compositions are polymerizable at ambient temperatures.

Abstract: A composite material comprises a reinforcing material carried in a polymer matrix material which is the polymerization product of a polymerizable composition comprising a di-activated vinyl compound, with the proviso that the di-activated vinyl compound is not a cyanoacrylate. The reinforcing materials may be a wide variety of substrates including thermally sensitive materials. Exemplary composites can be molded and cured at ambient temperatures. Also disclosed are laminate materials having layered materials adhered by curing a di-activated vinyl polymerizable composition.

Abstract: A free radical curable liquid for inkjet printing of food packaging materials includes no initiator or otherwise one or more initiators selected from the group consisting of non-polymeric di- or multifunctional initiators, oligomeric initiators, polymeric initiators, and polymerizable initiators; wherein the polymerizable composition of the liquid consists of: a) 25-100 wt % of one or more polymerizable compounds A having at least one acrylate group G1 and at least one second ethylenically unsaturated polymerizable functional group G2 different from the group G1; b) 0-55 wt % of one or more polymerizable compounds B selected from the group consisting of monofunctional acrylates and difunctional acrylates; and c) 0-55 wt % of one or more polymerizable compounds C selected from the group consisting of trifunctional acrylates, tetrafunctional acrylates, pentafunctional acrylates and hexafunctional acrylates.

Abstract: The present disclosure is concerned with improved curable adhesive compositions for anchoring elements in a structural body that exhibit low temperature versus standard temperature degree of cures that are at least 50% or higher. The compositions include, in a first portion, a reactive resin, an acetoacetoxy functional monomer and a silane monomer. By using phthalate-free constituents in the formulation, a further 10% increase in strength and durability of the resins at standard temperatures may be realized after curing at low temperatures. Improvements in the adhesive compositions that relate to increased shelf life are also presented.

Abstract: A one part, storage stable polymerizable formulation is provided that includes an ethenically unsaturated polymerizable compound intermixed with a free radical polymerization initiator and an organic solvent. The organic solvent provides storage stability and upon evaporation of the solvent, the rate of polymerization of the compound accelerates independent of addition of a second part. The formulation includes at least 30 total weight percent solids upon cure. Optional additives to the formulation include at least one of a cure accelerator, a filler, a plasticizer, a colorant, and a cure inhibitor. A process for forming a polymerized coating on an article involves the application of this formulation to the substrate of an article and allowing sufficient time for the solvent to evaporate to form the polymerized coating on the article. The substrate of the article forms a corrosion barrier even without prior removal of a native corrosion layer on a surface of the substrate of the article.

Abstract: The present invention relates to (meth)acrylated compounds (A) prepared from (a) at least one cyclic ether polyol, (b) at least one linking compound (b1) and/or (b2), wherein the linking compound (b1) is selected from cyclic compounds (b11) containing at least one (I) group in the cycle where X=O or NH, from hydroxy acids (b12) and/or from alkylene oxides (b13) containing from 2 to 4 carbon atoms and the linking compound (b2) is selected from epihalohydrins or polyisocyanates, (c) a (meth)acrylating compound; and to their use in radiation curable compositions for the coatings, inks, overprint varnishes, adhesives and composites.

Abstract: A method for the manufacture of a transparent, scratch resistant film, comprising: (1) cleaning a surface of a flexible substrate; (2) altering the surface energy of the surface of the flexible substrate; (3) coating the surface of the flexible substrate with a transparent, scratch resistant coating comprising functionalized group monomers and a solvent; (4) wetting the transparent, scratch resistant coating; and (5) forming a cross-linked polymer structure by curing the transparent, scratch resistant coating.

Abstract: The present invention provides a vulcanizable composition containing a specific hydrogenated nitrile rubber, at least one cross-linking agent and carbon nanotubes, a process for preparing such composition and the use thereof for preparing vulcanizates. Said vulcanizates exhibit excellent heat performance, oil resistance and mechanical strength.

Abstract: A binder composition for a rechargeable battery, including a binder polymer having a glass transition temperature (Tg) of 20° C. or less, and having a storage modulus (60° C.) of 50-150 MPa. The binder composition according to an embodiment can improve life characteristics of the rechargeable battery by efficiently controlling expansion of a negative electrode plate.

Abstract: To provide a photopolymerizable inkjet ink, which contains photopolymerizable monomers containing at least one selected from the following compound group (A) compounds of which are negative for skin sensitization, and at least one selected from the following compound group (B) compounds of which are negative for skin sensitization, wherein the compound group (A) is a compound group consisting of caprolactone-modified dipentaerythritol hexaacrylate, polyethoxylated tetramethylol methane tetraacrylate, ethylene oxide-modified bisphenol A diacrylate, caprolactone-modified hydroxy pivalic acid neopentyl glycol diacrylate, polypropylene glycol diacrylate [CH2?CH—CO—(OC3H6)n-OCOCH?CH2 (n?12)], hydroxyethyl acryl amide, trimethylol propane trimethacrylate, and tricyclodecane dimethanol dimethacrylate, and the compound group (B) is a compound group consisting of ethylene oxide-modified phenolacrylate, isostearyl acrylate, ethylene oxide-modified trimethylol propane trimethacrylate, stearyl methacrylate, and glycerin

Abstract: The invention relates to an inorganic-organic hybrid material which comprises an inorganic component and an organic component, has a content of the inorganic component of 20-80% by mass, and has a refractive index of 1.60 or higher, wherein, when preparing a strip specimen having a thickness of 1,000 ?m, a width of 5 mm and a length of 70 mm by using the inorganic-organic hybrid material and winding the specimen by 180° on a cylindrical metal rod having a diameter of 10 mm at 25° C., the specimen does not crack.

Abstract: Methods of forming a curable pre-impregnated composite precursor material with radiation (e.g., actinic or electron-beam) curable resin composition systems are provided, as are the curable pre-impregnated composite precursor materials themselves. The resin systems have reversible temperature-viscosity control, which are advantageously used to form curable pre-impregnated composite precursor materials (pre-preg) that can be cured to form a composite article. The uncured resin composition comprises: (a) an acrylate or a methacrylate monomer; (b) an oligomer species selected from the group consisting of: polyethers, polyesters, epoxies, and combinations thereof; and (c) a photoinitiator. The uncured resin has a first viscosity at 21° C. (70° F.) of ?about 200,000 centipoise (cP) and a second viscosity of ?about 5,000 cP at 65° C. (149° F.) or above.

Abstract: Process for preparing an aqueous polymer dispersion with small polymer particles.

Abstract: This curable resin composition comprises (A) a polymerizable (meth)acrylic-based monomer, (B) a thiourea compound component, and (C) a peroxide component having a structure of formula (1), and may have (D) a (meth) acrylic-based polymer component as an optional component. (In formula (1), R is a C1-15 hydrocarbon group.) In the curable resin composition, preferably, the content of the (A) component is 5-100 mass % and the content of the (D) component is 0-95 mass % relative to the total mass of the (A) component and the (D) component.

Abstract: The present invention provides organopolysiloxane comprising one or more unsaturated bond-containing group(s) in one molecule and having constitutional units F1, M1, and T in any combination of (i) F1 and M1, (ii) F1 and T, and (iii) F1, M1, and T: wherein R1 represents any selected from the group consisting of a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, a substituted or unsubstituted aryl group, and a substituted or unsubstituted aralkyl group; R2 represents an unsaturated bond-containing group having 2 to 10 carbon atoms; X represents a divalent hydrocarbon group having 2 to 10 carbon atoms; Y represents a divalent hydrocarbon group having 2 to 10 carbon atoms; and a, b, and c each independently represent an integer of 1 or larger, wherein F1 represents a unit constituting cyclic organopolysiloxane.

Abstract: A free radical curable liquid for inkjet printing of food packaging materials includes no initiator or otherwise one or more initiators selected from the group consisting of non-polymeric di- or multifunctional initiators, oligomeric initiators, polymeric initiators, and polymerizable initiators; and a polymerizable composition of the liquid consists essentially of: a) 25-100 wt % of one or more polymerizable compounds A having at least one acrylate group G1 and at least one second ethylenically unsaturated polymerizable functional group G2 selected from the group consisting of a vinlyether group, an allylether group, and a allylester group; b) 0-55 wt % of one or more polymerizable compounds B selected from the group consisting of monofunctional acrylates and difunctional acrylates; and c) 0-55 wt % of one or more polymerizable compounds C selected from the group consisting of trifunctional acrylates, tetrafunctional acrylates, pentafunctional acrylates and hexafunctional acrylates.

Abstract: A curable polymeric composition is herein disclosed. According to one embodiment, a curable polymeric composition comprises a thermoplastic block copolymer containing at least two polymer blocks A separated by at least one polymer block B. Each polymer block A is primarily a poly(monovinyl aromatic hydrocarbon) block, and polymer block B includes hydrogenated conjugated didne. The solid curable polymeric composition further comprises a curable functional compound compatible with polymer block A. The solid curable polymeric composition optionally comprises an initiator, a plasticizer, an antioxidant; a tackifyer and an aromatic resin.

Abstract: Disclosed is a resin composition for laser engraving, comprising: (Component A) a macroinitiator having a structure represented by any one of Formulae I to V below obtained by step-growth polymerization; and (Component B) a polymerizable compound.

Abstract: The present invention is directed to a nonaqueous pressure-sensitive adhesive that may be used in medicinal tape preparations for percutaneous absorption. The adhesive may comprise a copolymer obtained by copolymerization of a (meth)acrylic monomer having an acetoacetyl group in the molecule and one or more monomers from among other (meth)acrylic monomers without acetoacetyl groups and copolymerizable vinyl monomers, in a nonaqueous solvent. Suitable (meth)acrylic monomers having an acetoacetyl group in the molecule are acetoacetoxyalkyl methacrylates, and especially 2-acetoacetoxyethyl methacrylate. The pressure-sensitive adhesive of the invention uses no polyamine derivatives, isocyanate compounds, polyvalent metal chelate compounds, etc., as crosslinking agents, and therefore toxicity is not a concern and skin is not irritated. A medicinal tape preparation for percutaneous absorption of the invention has superior adhesive strength and cohesive strength, and is highly safe with low skin irritation.

Abstract: A radiation curable liquid coating composition comprising 1 to 90 wt % of at least one multifunctional (meth)acrylated oligomer; 10 to 80 wt % of at least one C8 to C20 monofunctional aliphatic alkyl (meth)acrylate; 0 to 40 wt % of at least one monomeric reactive diluent wherein (a)+(b)+(c)=100%; and additionally comprising 0.1 to 15 wt % of matting agent by weight of the coating composition.

Abstract: A method of preparing a resin composition for hard coat, comprises: a first step of obtaining a polyfunctional (meth)acrylate monomer modifying agent by addition reaction between a modifying agent having a thiol group and a three- or more functional (meth)acrylate monomer to form a covalent bond between the thiol group and acryloyl group and/or methacryloyl group, and a second step of modifying metal oxide microparticles with the polyfunctional (meth)acrylate monomer modifying agent that is obtained from the first step.

Abstract: An optically polymerizable inkjet ink including an optically polymerizable monomer having a Stimulation Index (SI) of less than 3 in a skin sensitization test as measured by Local Lymph Node Assay (LLNA), a molecule cleavage type optical polymerization initiator, a hydrogen-extracting type optical polymerization initiator, and an amine compound serving as a polymerization accelerator.

Abstract: This invention relates to polymerizable compositions comprising a salt of a barbituric acid derivative. The compositions are typically shelf-life stable and may be polymerized through mixing of an acidic component with the salt of a barbituric acid derivative.

Abstract: A binder for secondary battery electrodes contains a copolymer latex obtained by emulsion polymerization of a monomer composition containing 12.0 to 39.5 wt % of an aliphatic conjugated diene-based monomer, 1.5 to 8.5 wt % of an unsaturated carboxylic acid alkyl ester monomer, 0.1 to 10.0 wt % of an ethylene-based unsaturated carboxylic acid monomer, and 42.0 to 86.4 wt % of a monomer that is copolymerizable therewith, wherein 50 to 100 wt % of the copolymer latex is toluene-insoluble.

Abstract: This invention relates to a process for producing coatings based on an LCST polymer and to formed articles obtainable by the process.

Abstract: Curable solid ink compositions, comprising a curable wax having a melting point under 40° C. as part of the ink vehicle, which are suitable for ink jet printing in applications that require high and/or variable levels of gloss. In particular, there is provided a novel high gloss, ultraviolet (UV) curable, phase change ink composition comprising a colorant and an ink vehicle comprising a gellant, a reactive diluent, a photoinitiator package, and a curable acrylate wax.

Abstract: The present invention relates to novel organic-inorganic silica particles, a preparation method thereof, and a hard coating composition containing the same, and more specifically, to organic-inorganic silica particles wherein an initiator is chemically bonded to hydroxyl groups (—OH) on the surface of the silica particles, a preparation method thereof, and a hard coating composition containing the same. A hard coating film with excellent abrasion resistance, scratch resistance and the like can be prepared by using the hard coating composition containing the organic-inorganic silica particles according to the present invention.

Abstract: The invention is directed to the use of maleic esters selected from compounds of formulae (I), (II) and (III), as copolymerizable emulsifiers in the emulsion polymerization of olefinically unsaturated monomers, in which A is a C3-C40 alkyl group; X, Y and Z independently are hydrogen or methyl; B and D independently are sulfate, phosphate or hydrogen; n and p independently are numbers in the range from 0 to 40; and m is a number in the range from 2 to 40.

Abstract: Provided is a UV curable type ink-jet ink composition containing a monomer A which is expressed by the following general formula (I): CH2?CR1—COOR2—O—CH?CH—R3??(I) (in the formula, R1 is a hydrogen atom or methyl radical, R2 is a bivalent organic residue radical having a carbon number in a range of 2 to 20, and R3 is a hydrogen atom or a univalent organic residue radical having a carbon number in a range of 1 to 11), a compound B containing five or more (meth)acryloyl radicals per molecule, and a monofunctional (meth)acrylate C having an aromatic ring skeleton, wherein the monofunctional (meth)acrylate C which is in a range of 5 to 35 wt % with respect to the total weight of the ink composition is contained.

Abstract: Provided is a method for producing a curable composition for imprints which excellent in patternability. Applied is a method for producing a curable composition for imprints, which comprises passing a curable composition comprising a polymerizable monomer (A) and a polymerizable initiator (B) through a filter having an effective filter area of 200 cm2 or more at least one time.

Abstract: Process for producing protective or surface coatings by coating of substrates with a radiation curable coating composition and subsequent radiation curing, wherein the radiation curable coating composition comprises a compound of the formula I in which R1 and R2 independently of one another are an organic radical having in each case at least one C atom, but where the sum of the C atoms of R1 and R2 is at least 4, or R1 and R2 together form a ring system comprising at least 4 C atoms, R3 is a hydrogen atom or Y, X is a C1 to C10 alkylene group, n and m independently of one another are 0 or an integer from 1 to 50, Y is a group selected from —CH?CH2; —CH2—CH?CH2; or and R4 can be an H atom, a methyl group or —CH2—C(?O)—OH, and R5 is an H atom and R6 is a —C(?O)—OH group or, alternatively, R6 is an H atom and R5 is a —C(?O)—OH group.

Abstract: The present invention is directed to a hardening composition comprising silica fine particles (a), a (meth)acrylate (b) having two or more ethylenically unsaturated groups and being free from cyclic structure, a (meth)acrylate (c) having an ethylenically unsaturated group and having an alicyclic structure, a polymerization initiator (d) and black inorganic fine particles (e), wherein the silica fine particles (a) are surface-treated with a silane compound (f) represented by the following general formula (1) and a silane compound (g) represented by the following general formula (2): (in the formula (1), R1 represents a hydrogen atom or a methyl group, R2 represents an alkyl group having 1 to 3 carbon atoms or a phenyl group, R3 represents a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms; q represents an integer of 1 to 6; and r represents an integer of 0 to 2, (in the formula (2), R4 is an alkyl group having 1 to 3 carbon atoms or a phenyl group which may have a substituent; R

Abstract: The present invention provides a method for tinting an optical substrate. The method includes the steps of applying a coating composition containing: a polymerisable monomer having a polyoxyalkylene backbone containing at least four contiguous oxyalkylene units, and an abrasion resistant agent and/or a high crosslinking polymerisable monomer to the optical substrate, polymerising the coating composition to form an abrasion resistant coating layer, and introducing a tinting compound into the coating layer to thereby tint the optical substrate. The invention also provides a coating composition and an optical substrate that is tinted according to the method of the invention.

Abstract: The present invention provides an inkjet ink composition, which has excellent ink-ejection reliability over a long time and capability of forming an image without defects such as white spots, and which includes: a pigment coated with a dispersant polymer; a water soluble polymerizable compound; a polymerization initiator; and water, the dispersant polymer being formed from a water soluble dispersant by crosslinking with a crosslinking agent.

Abstract: A syrup composition of the present invention comprises a mixture of monomers (A), each having a molecular mass of 130 to 300 and one (meth)acryloyl group; a resin (C) which is soluble in the monomers (A) and has a glass transition temperature of 20 to 155° C.; a wax (D); and a tertiary amine (E), wherein the monomers (A) contain a heterocyclic ring-containing (meth)acrylate (a1), an oligoethylene glycol monoalkyl ether (meth)acrylate (a2), and a hydroxyalkyl (meth)acrylate (a3) having a hydroxyalkyl group with 2 or 3 carbon atoms. The syrup composition does not substantially contain a polyvalent metal soap.

Abstract: A crosslinkable moulding composition comprises: (1) a functionalised isocyanate product having at least six ethylenically unsaturated groups which is the reaction product of (i) an isocyanate component having an isocyanate functionality of two or more, and (ii) an ethylenically unsaturated component having at least one functional group that is reactive with an isocyanate group of the isocyanate component and at least two ethylenically unsaturated groups; and (2) a monomer component comprising a cross-linking monomer having at least two ethylenically unsaturated groups, wherein at least one of an ethylenically unsaturated component (ii) and/or a monomer component (2) are selected to have at least three ethylenically unsaturated groups. The moulding compositions are especially suitable for reinforcement and thermal curing. Example crosslinked resins derived from such moulding compositions are shown to be capable of achieving high heat deflection temperatures, often in excess of 260° C.

Abstract: The present invention provides a composition suitable for a dental composition. The present invention is a composition containing: a polymerizable monomer (A) having an unconjugated carbon chain with at least four carbon atoms bonded continuously, at least two polymerizable groups, and at least two hydroxyl groups; and a polymerizable monomer (B) having one polymerizable group and at least one hydroxyl group. When a suitable component is added to this composition, the resultant composition can be used suitably for dental materials such as a primer, bonding material, composite resin, and cement.

Abstract: A hard coating composition and a laminate including a hard coating layer, the hard coating composition including an alkylene glycol acrylic monomer; a polyfunctional acrylic monomer; and a polymerization initiator, wherein the alkylene glycol acrylic monomer is present in an amount of about 5% to about 69% by weight, based on a total solids content of the composition.

Abstract: New process conditions are described and more particularly emulsion polymerization of compositions which are based on copolymers of vinyl acetate, straight chain ?-olefin and an optional third different olefinically-unsaturated co-monomer in which the ?-olefin is emulsified prior to the addition into the polymerization mixture.

Abstract: The invention is directed to the use of maleic esters selected from compounds of formulae (I), (II) and (III), as copolymerizable emulsifiers in the emulsion polymerization of olefinically unsaturated monomers, in which A is a C3-C40 alkyl group; X, Y and Z independently are hydrogen or methyl; B and D independently are sulfate, phosphate or hydrogen; n and p independently are numbers in the range from 0 to 40; and m is a number in the range from 2 to 40.

Abstract: Porous polymeric resins, reaction mixtures and methods that can be used to prepare the porous polymeric resins, and uses of the porous polymeric resin are described. More specifically, the polymeric resins typically have a hierarchical porous structure plus reactive groups that can be used to interact with or react with a variety of different target compounds. The reactive groups can be selected from an acidic group or a salt thereof, an amino group or salt thereof, a hydroxyl group, an azlactone group, a glycidyl group, or a combination thereof.

Abstract: The invention provides an ink composition having at least (A) a polymerization initiator, (B) an ester or amide of (meth)acrylic acid having a 1,3-dioxolane ring skeleton or a 1,3-dioxane ring skeleton or (B?) an ester or amide of (meth)acrylic acid having a 1,3-diketone structure, and (C) a colorant. The invention further provides an inkjet recording method and a method for producing a planographic printing plate, each of which includes at least (I) ejecting the ink composition onto a hydrophilic support and (II) curing the ink composition by irradiating the ejected ink composition with active radiation so as to form a hydrophobic image region on the hydrophilic support. The invention furthermore provides a planographic printing plate formed by the method for producing a planographic printing plate.

Abstract: The present invention provides a method for tinting an optical substrate. The method includes the steps of applying a coating composition containing: a polymerisable monomer having a polyoxyalkylene backbone containing at least four contiguous oxyalkylene units, and an abrasion resistant agent and/or a high crosslinking polymerisable monomer to the optical substrate, polymerising the coating composition to form an abrasion resistant coating layer, and introducing a tinting compound into the coating layer to thereby tint the optical substrate. The invention also provides a coating composition and an optical substrate that is tinted according to the method of the invention.

Abstract: The present invention provides a polymerizable composition that exhibits excellent adhesive properties to a tooth structure (particularly dentin) when applied as a dental material, and a polymerizable monomer that is used as a component of the polymerizable composition. The present invention is a polymerizable monomer (A) that is a compound having at least two polymerizable groups. The polymerizable monomer (A) has a retention time of 7 minutes to 30 minutes in a high-performance liquid chromatography (HPLC) measurement conducted under a condition in which a column with an inner diameter of 3.9 mm and a length of 300 mm, packed with a C18 packing material having been crushed to have an average particle size of 10 ?m and a pore size of 125 angstroms, is used, an eluent is a mixed solvent of methanol and water contained at a ratio of 3:7, a flow rate is 1.0 mL/minute, a measurement temperature is 50° C.

Abstract: The actinic ray curable composition has a radically, photopolymerizable compound, and a non-reactive compound having a viscosity at 25° C. of from 0.1 to 20 mPa·s and a boiling point of not less than 150° C.

Abstract: Process for preparing an aqueous polymer dispersion using alkenes of 5 to 12 carbon atoms and use of the resultant aqueous polymer dispersions as adhesives components.

Abstract: The present invention relates to an aqueous pigment dispersion that shows excellent dispersibility and storage stability, an inkjet ink that shows excellent jetability, water resistance, and adhesion, and a process for producing an aqueous pigment dispersion that shows excellent dispersibility and storage stability, as well as superior jetability, water resistance and adhesion. An aqueous pigment dispersion of the present invention comprises a dispersion formed by dispersing a monoalkyl maleate graft polymer of a maleic anhydride/?-olefin copolymer in water in the presence of a base, a pigment, and an aqueous medium.

Abstract: To provide a process for producing polymer particles which are spherical and have smooth surfaces and small contents of oil- and the solvent-soluble at the time of being compounded. Polymer particles are produced by adding 0.099 to 47 parts by mass of a crosslinking vinyl monomer to 100 parts by mass of a vinyl monomer (referred to hereinafter as the monomer) during polymerization reaction at a degree of monomer polymerization of 1 to 100% in order to polymerize the monomer in a solvent in the presence of a dispersant and a polymerization initiator to give polymer particles.