A masterbatch manufacturing method comprising: an operation in which a natural rubber latex, and a rubber latex having a mass-average molecular weight that is less than a mass-average molecular weight of the natural rubber latex, are mixed to obtain a pre-slurry-mixing rubber latex for which a mass-average-molecular-weight-to-number-average-molecular-weight ratio is 6 to 10; an operation in which the pre-slurry-mixing rubber latex and a filler slurry are mixed to obtain a pre-coagulation liquid mixture; and an operation in which the pre-coagulation liquid mixture is coagulated.

A method for producing a polymer latex includes: a preparation step of reducing the weight average molecular weight of a conjugated diene polymer (A) by 20 to 70 mass %, thereby obtaining an organic solvent solution containing a conjugated diene polymer (B) having a weight average molecular weight lower than that of the conjugated diene polymer (A); and an emulsification step of emulsifying the organic solvent solution in water in the presence of a surfactant, thereby obtaining a polymer latex.

A method for producing a synthetic polyisoprene latex, including a step of mixing a latex of synthetic polyisoprene (A) synthesized by use of a Ziegler type catalyst and a latex of synthetic polyisoprene (B) synthesized by use of an organic alkali metal catalyst at a weight ratio of synthetic polyisoprene (A): synthetic polyisoprene (B)=10:90 to 90:10. In the method, preferably, the weight average molecular weight of the synthetic polyisoprene (A) is 100,000 to 3,000,000 and the weight average molecular weight of the synthetic polyisoprene (B) is 1,000,000 to 5,000,000.

To provide a novel expanded polystyrene-based resin formed product that is excellent in expandability, mechanical strength, hardness, antistatic property, heat resistance and flame retardancy and does not generate squeak noises, and a production method thereof. Provided is expandable polystyrene-based resin particles having rubber and melamine cyanurate on the surfaces thereof.

A resin film comprising a multilayer structure acrylic polymer and the film having an acid value of not more than 0.018 mmol/g in an acetone insoluble matter, an acid value of not more than 0.012 mmol/g in an acetone soluble matter, a glass transition temperature of not less than 80 C. and a thickness of 5 to 300 pm is obtained by a method comprising emulsion polymerization for producing a latex comprising multilayer structure acrylic polymer, coagulating the latex comprising the multilayer structure acrylic polymer to obtain a slurry, washing and dehydrating the slurry, drying the dehydrated slurry to remove the multilayer structure acrylic polymer, mixing 0 to 35% by mass of an acrylic resin and 65 to 100% by mass of the removed multilayer structure acrylic polymer and subjecting the resultant mixture melted to an extrusion molding.

A method for producing a polymer latex, includes a step of emulsifying a polymer solution of a synthetic polyisoprene and/or a styrene-isoprene-styrene block copolymer, in water in the presence of a rosin and/or a rosin metal salt, thereby obtaining an emulsified liquid, wherein the rosin and/or the rosin metal salt to be used have/has a total content rate of abietic acid, neoabietic acid and palustric acid, and salts thereof, of 5% by weight or less.

The present invention aims to provide a method for producing a masterbatch with improved rubber physical properties such as tensile strength at break, rigidity, and fuel economy at high productivity by enhancing the amount of fillers incorporated into rubber and the dispersibility of fillers in rubber, as well as related products. The present invention relates to a method for producing a masterbatch, including: step (1) of mixing a rubber latex having a zeta potential of 100 to 20 mV with a filler dispersion having a zeta potential of 120 to 10 mV to prepare a latex compound; step (2) of adjusting the zeta potential of the latex compound obtained in step (1) to 30 to 0 mV; and step (3) of solidifying the coagulum obtained in step (2) with an organic solvent.

The invention relates to an elastomeric film-forming composition comprising (a) a copolymer formed from monomers consisting of chlorobutadiene and an ethylenically unsaturated carboxylic acid or ester, and (b) one or more cross-linking agents. The invention also relates to dipped articles, gloves, methods of manufacture and uses involving the composition.

The present invention relates to thermoplastic molding compounds F containing at least two graft rubbers P-I and P-II which are processed by the co-precipitation of a mixture of the respective emulsions containing P-I and P-II. The present invention further relates to a method for producing such thermoplastic molding compounds F and to molded bodies obtained from a thermoplastic molding compound F according to the invention.

A polymer composition may include at least one ethylene-vinyl acetate copolymer and at least one farnesene polymer. A process for producing a polymer composition may include mixing the at least one ethylene-vinyl acetate copolymer with the at least one farnesene polymer, thereby producing the polymer composition that includes at least one ethylene-vinyl acetate copolymer and at least one farnesene polymer.