The present invention provides a process for making a silica masterbatch that contains hydrophobated silica, solution-made rubber and emulsion-made rubber. Hydrophobated silica is mixed into a latex emulsion. Solution-rubber crumb in an aqueous suspension is mixed into the latex emulsion, which is coagulated, and a crumb is recovered, further homogenized, dried and baled to yield the silica masterbatch. A well-dispersed mixture of hydrophobated silica and emulsion-made rubber is added into a steam distillation step of a solution-rubber process from which a silica masterbatch is recovered. The emulsion-made rubber can be omitted to make a silica masterbatch of solution rubber and silica without emulsion rubber. The silica masterbatch has physical properties similar to those found in a comparable dry-mixed composition, but the silica masterbatch can be incorporated more easily and less expensively into tires and other rubber products than the dry-mixed composition.

An object of the present invention is to provide an impact modifier that provides impact resistance to a molded object obtained by molding a resin composition such as polycarbonate at a high temperature, and exhibits more excellent heat stability (preservation of mechanical properties after a wet heat test, discoloration, and flame retardance), and a thermoplastic resin composition including the impact modifier. The polyorganosiloxane-containing-rubber latex, in which a total amount of sulfate ions and sulfonate ions included in 100 g of the solid content is 2.4 mmol or less, a powder thereof, and a resin composition including the powder and a resin. Further, a molded object thereof and a production method therefor are provided.

The invention relates to composite polymer modifiers for thermoplastic resins, and especially for polyvinyl chloride (PVC). The composite modifier is an intimate blend of mineral filler and polymeric process aid, which is formed by the co-powderization of aqueous emulsions, suspensions or slurries of one or more mineral filler(s) and process aid(s). The resulting composite modifier provides more effective modification of the thermoplastic resin than by the use of the dried components formed separately. The composite modifier may also contain other co-powderized components such as impact modifiers, for additional benefits.

The invention relates to composite polymer modifiers for thermoplastic resins, and especially for polyvinyl chloride (PVC). The composite modifier is an intimate blend of mineral filler and polymeric process aid, which is formed by the co-powderization of aqueous emulsions, suspensions or slurries of one or more mineral filler(s) and process aid(s). The resulting composite modifier provides more effective modification of the thermoplastic resin than by the use of the dried components formed separately. The composite modifier may also contain other co-powderized components such as impact modifiers, for additional benefits.

To provide a method for producing modified polytetrafluoroethylene, in which formation of a fluorinated oligomer as a by-product is little. A method for producing modified polytetrafluoroethylene which contains substantially no C.sub.6-34 fluorinated oligomer containing hydrophilic functional groups and which contains substantially no fluorinated surfactant, the method comprising conducting copolymerization of tetrafluoroethylene and a monomer having a polar group, in a liquid dispersion 1 comprising a polymer containing units derived from a non-fluorinated monomer and an aqueous medium, or in a solution 2 obtainable by mixing at least one member selected from the group consisting of a polyalkylene oxide compound and a hydrocarbon-containing surfactant, with an oxidizing agent, in an aqueous medium, under such a condition that the amount of the monomer having a polar group to be used, is at most 0.150 mass % to the whole amount of tetrafluoroethylene, to obtain modified polytetrafluoroethylene.

To provide a method for producing modified polytetrafluoroethylene, in which formation of a fluorinated oligomer as a by-product is little. A method for producing modified polytetrafluoroethylene which contains substantially no C.sub.6-34 fluorinated oligomer containing hydrophilic functional groups and which contains substantially no fluorinated surfactant, the method comprising conducting copolymerization of tetrafluoroethylene and a monomer having a polar group, in a liquid dispersion 1 comprising a polymer containing units derived from a non-fluorinated monomer and an aqueous medium, or in a solution 2 obtainable by mixing at least one member selected from the group consisting of a polyalkylene oxide compound and a hydrocarbon-containing surfactant, with an oxidizing agent, in an aqueous medium, under such a condition that the amount of the monomer having a polar group to be used, is at most 0.150 mass % to the whole amount of tetrafluoroethylene, to obtain modified polytetrafluoroethylene.

A method of producing a carboxyl group-containing nitrile rubber including a coagulation step of coagulating a carboxyl group-containing nitrile rubber component by mixing a monovalent metal salt and a polymer flocculating agent into a carboxyl group-containing nitrile rubber latex having an iodine value of 120 or less, wherein the monovalent metal salt is compounded in an amount of 3 to 25 parts by weight and the polymer flocculating agent is compounded in an amount of 0.01 to 10 parts by weight relative to 100 parts by weight of a rubber solid content in the latex, and a weight ratio of the monovalent metal salt/the polymer flocculating agent is in the range of 10 to 500

A method of producing a carboxyl group-containing nitrile rubber including a coagulation step of coagulating a carboxyl group-containing nitrile rubber component by mixing a monovalent metal salt and a polymer flocculating agent into a carboxyl group-containing nitrile rubber latex having an iodine value of 120 or less, wherein the monovalent metal salt is compounded in an amount of 3 to 25 parts by weight and the polymer flocculating agent is compounded in an amount of 0.01 to 10 parts by weight relative to 100 parts by weight of a rubber solid content in the latex, and a weight ratio of the monovalent metal salt/the polymer flocculating agent is in the range of 10 to 500

The present invention relates to polyvinyl chloride aggregate particles, in which a particle diameter D50 at a cumulative volume percentage of 50 vol % in a volume particle size distribution is 0.5 μm or more and 5.0 μm or less, and a particle diameter D90 at a cumulative volume percentage of 90 vol % in the volume particle size distribution is 8.0 μm or less, and a Na concentration in the polyvinyl chloride aggregate particles is 90 ppm or less. The present invention relates to a composition for a metal can coating material, a composition for a marking film and a method for producing the same, and a coating film that contain the polyvinyl chloride aggregate particles. This provides polyvinyl chloride aggregate particles capable of imparting high transparency and retort resistance to a coating film of a metal can, and/or capable of imparting high transparency and water resistance to a marking film.

The present invention relates to polyvinyl chloride aggregate particles, in which a particle diameter D50 at a cumulative volume percentage of 50 vol % in a volume particle size distribution is 0.5 μm or more and 5.0 μm or less, and a particle diameter D90 at a cumulative volume percentage of 90 vol % in the volume particle size distribution is 8.0 μm or less, and a Na concentration in the polyvinyl chloride aggregate particles is 90 ppm or less. The present invention relates to a composition for a metal can coating material, a composition for a marking film and a method for producing the same, and a coating film that contain the polyvinyl chloride aggregate particles. This provides polyvinyl chloride aggregate particles capable of imparting high transparency and retort resistance to a coating film of a metal can, and/or capable of imparting high transparency and water resistance to a marking film.