A polymerization reactor for producing aqueous polymer dispersions by radically initiated emulsion polymerization of one or more ethylenically unsaturated monomers in the presence of one or more protective colloids and/or emulsifiers, is cleaned by initially charging an aqueous mixture comprising one or more ethylenically unsaturated monomers, one or more protective colloids and/or emulsifiers, but no oxidation initiator, the proportion of ethylenically unsaturated monomers being 20 to 70% by weight of the aqueous mixture, heating the aqueous mixture to a temperature of 50° C. to 100° C. for 5 minutes to 3 hours, adding one or more initiators and optionally further starting materials, initiating polymerization, removing the aqueous polymer dispersion thus obtained from the polymerization reactor and post-treating the dispersion to remove wall deposits detached during the process.

A polymerization reactor for producing aqueous polymer dispersions by radically initiated emulsion polymerization of one or more ethylenically unsaturated monomers in the presence of one or more protective colloids and/or emulsifiers, is cleaned by initially charging an aqueous mixture comprising one or more ethylenically unsaturated monomers, one or more protective colloids and/or emulsifiers, but no oxidation initiator, the proportion of ethylenically unsaturated monomers being 20 to 70% by weight of the aqueous mixture, heating the aqueous mixture to a temperature of 50° C. to 100° C. for 5 minutes to 3 hours, adding one or more initiators and optionally further starting materials, initiating polymerization, removing the aqueous polymer dispersion thus obtained from the polymerization reactor and post-treating the dispersion to remove wall deposits detached during the process.

To provide a fluorinated elastic copolymer having a low content of metal elements and being excellent in crosslinkability. This fluorinated elastic copolymer has iodine atoms and has units a based on tetrafluoroethylene, units b based on a monomer having one polymerizable unsaturated bond (but excluding tetrafluoroethylene), and units c based on a fluorinated monomer having at least two polymerizable unsaturated bonds, wherein the metal content is at least 0.3 ppm by mass and at most 20.0 ppm by mass.

To provide a fluorinated elastic copolymer having a low content of metal elements and being excellent in crosslinkability. This fluorinated elastic copolymer has iodine atoms and has units a based on tetrafluoroethylene, units b based on a monomer having one polymerizable unsaturated bond (but excluding tetrafluoroethylene), and units c based on a fluorinated monomer having at least two polymerizable unsaturated bonds, wherein the metal content is at least 0.3 ppm by mass and at most 20.0 ppm by mass.

Method of reducing the amount of a fluorinated acid or its salts from a fluoropolymer, the method comprises: (i) providing a composition containing particles of the fluoropolymer, (ii) contacting the fluoropolymer particles with a treatment composition comprising at least one organic liquid; and, optionally, further comprising (iii) isolating, washing and subjecting the fluoropolymer to drying treatment, and wherein the fluoropolymer contains units derived from tetrafluoroethene (TFE) and is selected from the group of fluoroelastomers and the group of fluoropolymers having a melting point of less than 150° C. Also provided are fluoropolymer and compositions containing such polymers that are essentially free of fluorinated acids and their salts.

Method of reducing the amount of a fluorinated acid or its salts from a fluoropolymer, the method comprises: (i) providing a composition containing particles of the fluoropolymer, (ii) contacting the fluoropolymer particles with a treatment composition comprising at least one organic liquid; and, optionally, further comprising (iii) isolating, washing and subjecting the fluoropolymer to drying treatment, and wherein the fluoropolymer contains units derived from tetrafluoroethene (TFE) and is selected from the group of fluoroelastomers and the group of fluoropolymers having a melting point of less than 150° C. Also provided are fluoropolymer and compositions containing such polymers that are essentially free of fluorinated acids and their salts.

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.

The present disclosure relates to a purification method of a polymerization solvent used in and recovered from the preparation of a polyolefin resin, which can effectively remove impurities, in particular polyolefin wax, from the polymerization solvent to obtain a purified polymerization solvent with high purity, and can improve energy efficiency.

The present disclosure relates to a purification method of a polymerization solvent used in and recovered from the preparation of a polyolefin resin, which can effectively remove impurities, in particular polyolefin wax, from the polymerization solvent to obtain a purified polymerization solvent with high purity, and can improve energy efficiency.

Provided is a particle suitable for a specimen test, which has high sensitization efficiency in a reaction with an antibody, shows high detection sensitivity as a latex reagent, hardly agglutinates during its storage, and hardly causes nonspecific adsorption even when not post-coated. The particle is a particle including a copolymer containing a monomer unit derived from a styrene-based monomer and a monomer unit derived from a glycidyl group-containing monomer, the particle being represented by the following general formula (1):

##STR00001##

in the general formula (1), L.sub.1 represents a copolymer moiety containing the monomer unit derived from the styrene-based monomer and the monomer unit derived from the glycidyl group-containing monomer, n represents from 4 to 11, and R.sup.1 and R.sup.2 each represent a hydrogen atom, an alkyl group, or a halogen.