Bridgestone Corporation

Kazuaki Someno

Kazuhiro Yanagisawa

Uchu Mukai

Kazuya Hatakeyama

Kouji Masaki

Yukari Kanda

Fumiteru Nishiura

Provided is a process for producing a wet masterbatch which, without deteriorating a reinforcing property of a rubber composition and rubber physical properties, micronizes a filler slurry by controlling an amount of functional groups on a filler surface, and improves filler dispersibility in the rubber wet masterbatch and the rubber composition. The process for producing a wet masterbatch comprises: a step of producing a slurry solution having a pH of 8 or more by dispersing carbon black having an average amount of surface acidic functional groups (&#x3bc;eq/m) of 0.15 or more and less than 3.00; a step of producing a mixture by mixing the slurry solution and a rubber latex solution in a liquid phase; and a step of drying the mixture.

Process for producing wet masterbatch, and wet masterbatch produced by said process

The natural rubber master batch of the present invention is prepared by mixing a natural rubber latex having its amide linkages cleaved and an aqueous slurry having a filler dispersed in water. Alternatively, the natural rubber master batch is prepared by a method including a step for mixing a natural rubber latex and an aqueous slurry containing dispersed fillers having a specific particle size distribution and a limited range of 24M4DBP absorption. The natural rubber composition of the present invention is prepared by compounding natural rubber, which contains non-rubber components prepared by cleaving amide linkages of natural rubber latex, with silica and/or a particular inorganic filler.

Natural rubber master batch, production method thereof, and natural rubber composition

A silica-blended rubber composition comprising 100 parts by weight of sulfur-vulcanizable rubber blended with 10 to 100 parts by weight of silica, 3 to 20% by weight of a silane coupling agent based on the silica and 1 to 20% by weight of sodium borate based on the silica. An alkoxy group-containing silane coupling agent is preferred as the silane coupling agent, and sodium tetraborate is preferred as the sodium borate.

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Tokyo, Japan

Kazuaki Someno