To provide a method capable of producing fluorinated polymer particles in which formation of fine particles or formation of large aggregates is sufficiently suppressed even in the case of a fluorinated polymer having high solubility in a solvent.

The method comprises the following steps (i) and (ii), being a method for producing particles of a fluorinated polymer (A) which has either one or both of structural units (u1) derived from tetrafluoroethylene and structural units (u2) having no sulfonic acid type functional group and having a cyclic structure and fluorine atoms, and which has structural units (u3) having a sulfonic acid type functional group, wherein the proportion of the structural units (u1) is from 0 to 82 mol % in all structural units (100 mol %) in the fluorinated polymer (A): (i) a step of preparing solution or dispersion of the fluorinated polymer (A) having the above fluorinated polymer (A) dissolved or dispersed in a solvent (B), wherein the following conditions (i-1) and (i-2) are satisfied: (i-1) the solvent (B) contains a good solvent (B2) wherein the solubility of the fluorinated polymer (A) is at least 30%, (i-2) even when the above solution or dispersion of the fluorinated polymer (A) is passed through a filter of 200 mesh made of stainless steel, no residue remains on the filter, (ii) a step of mixing the above solution or dispersion of the fluorinated polymer (A) and a solvent (C) to aggregate the fluorinated polymer (A) to form particles of the fluorinated polymer (A), wherein the following conditions (ii-1) to (ii-3) are satisfied: (ii-1) the solvent (C) contains a poor solvent (C1) whereby the degree of swelling of the fluorinated polymer (A) is at most 100%, (ii-2) the degree of swelling of the fluorinated polymer (A) by a mixed solvent (BC) of the solvent (B) and the solvent (C) is from 70 to 250%, (ii-3) the ratio of the mass (W.sub.C) of the solvent (C) to the mass (W.sub.B) of the solvent (B) is from 1 to 5.

To provide a method capable of producing fluorinated polymer particles in which formation of fine particles or formation of large aggregates is sufficiently suppressed even in the case of a fluorinated polymer having high solubility in a solvent.

The method comprises the following steps (i) and (ii), being a method for producing particles of a fluorinated polymer (A) which has either one or both of structural units (u1) derived from tetrafluoroethylene and structural units (u2) having no sulfonic acid type functional group and having a cyclic structure and fluorine atoms, and which has structural units (u3) having a sulfonic acid type functional group, wherein the proportion of the structural units (u1) is from 0 to 82 mol % in all structural units (100 mol %) in the fluorinated polymer (A): (i) a step of preparing solution or dispersion of the fluorinated polymer (A) having the above fluorinated polymer (A) dissolved or dispersed in a solvent (B), wherein the following conditions (i-1) and (i-2) are satisfied: (i-1) the solvent (B) contains a good solvent (B2) wherein the solubility of the fluorinated polymer (A) is at least 30%, (i-2) even when the above solution or dispersion of the fluorinated polymer (A) is passed through a filter of 200 mesh made of stainless steel, no residue remains on the filter, (ii) a step of mixing the above solution or dispersion of the fluorinated polymer (A) and a solvent (C) to aggregate the fluorinated polymer (A) to form particles of the fluorinated polymer (A), wherein the following conditions (ii-1) to (ii-3) are satisfied: (ii-1) the solvent (C) contains a poor solvent (C1) whereby the degree of swelling of the fluorinated polymer (A) is at most 100%, (ii-2) the degree of swelling of the fluorinated polymer (A) by a mixed solvent (BC) of the solvent (B) and the solvent (C) is from 70 to 250%, (ii-3) the ratio of the mass (W.sub.C) of the solvent (C) to the mass (W.sub.B) of the solvent (B) is from 1 to 5.

Provided is a method of preparing a graft polymer, which includes: polymerizing a monomer mixture comprising a carboxylic acid monomer and methyl acrylate, wherein the carboxylic acid monomer is included at 1.5 to 2.5 wt %, and thus preparing an acrylic coagulant having an average particle diameter of 60 to 70 nm; polymerizing diene-based monomers in the presence of an emulsifier containing a salt of a compound and thus preparing a first diene-based rubber polymer; enlarging the first diene-based rubber polymer using the acrylic coagulant and thus preparing a second diene-based rubber polymer; and graft-polymerizing an aromatic vinyl-based monomer and a vinyl cyanide-based monomer to the second diene-based rubber polymer and thus preparing a graft polymer.

Provided is a method of preparing a graft polymer, which includes: polymerizing a monomer mixture comprising a carboxylic acid monomer and methyl acrylate, wherein the carboxylic acid monomer is included at 1.5 to 2.5 wt %, and thus preparing an acrylic coagulant having an average particle diameter of 60 to 70 nm; polymerizing diene-based monomers in the presence of an emulsifier containing a salt of a compound and thus preparing a first diene-based rubber polymer; enlarging the first diene-based rubber polymer using the acrylic coagulant and thus preparing a second diene-based rubber polymer; and graft-polymerizing an aromatic vinyl-based monomer and a vinyl cyanide-based monomer to the second diene-based rubber polymer and thus preparing a graft polymer.

The present invention relates to a method of preparing a thermoplastic resin, a thermoplastic resin prepared by the same, and a thermoplastic resin composition including the same. More specifically, the method of the present invention includes a step of performing acid coagulation of emulsion polymerization latex, a step of treating coagulated slurry with a base and performing dehydration, and a step of adding a metal salt and water to dehydrated wet powder to adjust pH to 9 or more. According to the present invention, the method may increase the productivity of a thermoplastic resin, and the thermoplastic resin prepared by the method has excellent mechanical strength, thermal stability, and appearance properties. In addition, when the thermoplastic resin of the present invention is used in coating, the thermoplastic resin has an effect of improving the adhesive strength and appearance quality of a coating film.

A method for manufacturing a fired body of a fluororesin includes a mixing step of mixing a fluororesin pulverized after firing and an unfired fluororesin powder aggregated after emulsion polymerization at a rate based on predetermined strength to produce a component to be fired, and a firing step of firing the component to be fired produced.

A method for manufacturing a fired body of a fluororesin includes a mixing step of mixing a fluororesin pulverized after firing and an unfired fluororesin powder aggregated after emulsion polymerization at a rate based on predetermined strength to produce a component to be fired, and a firing step of firing the component to be fired produced.

The present invention relates to a method of preparing an ABS graft copolymer and a method of preparing a thermoplastic resin composition including the ABS graft copolymer. More specifically, the present invention relates to a method of preparing an ABS graft copolymer, in which a predetermined amount of a vinyl aromatic compound and a predetermined amount of a vinyl cyanide compound are grafted to a small-diameter rubber latex before enlarging particle size of the small-diameter rubber latex is performed, and then enlarging particle size of the small-diameter rubber latex is performed by adding a certain amount of a polymer coagulant, and to a method of preparing a thermoplastic resin composition including the ABS graft copolymer. According to the present invention, latex stability may be improved, and an ABS graft copolymer having excellent impact resistance may be prepared.

The present invention relates to a method of preparing an ABS graft copolymer and a method of preparing a thermoplastic resin composition including the ABS graft copolymer. More specifically, the present invention relates to a method of preparing an ABS graft copolymer, in which a predetermined amount of a vinyl aromatic compound and a predetermined amount of a vinyl cyanide compound are grafted to a small-diameter rubber latex before enlarging particle size of the small-diameter rubber latex is performed, and then enlarging particle size of the small-diameter rubber latex is performed by adding a certain amount of a polymer coagulant, and to a method of preparing a thermoplastic resin composition including the ABS graft copolymer. According to the present invention, latex stability may be improved, and an ABS graft copolymer having excellent impact resistance may be prepared.

Pressure-responsive particles include pressure-responsive base particles and fatty acid metal salt particles, in which the pressure-responsive base particles contain a styrene-based resin which contains styrene and other vinyl monomers as polymerization components and a (meth)acrylic acid ester-based resin which contains at least two kinds of (meth)acrylic acid esters as polymerization components and in which amass ratio of the (meth)acrylic acid esters to all polymerization components is 90% by mass or higher, the pressure-responsive particles have at least two glass transition temperatures, and a difference between the lowest glass transition temperature and the highest glass transition temperature is 30° C. or higher.