| abstract |
PCT No. PCT/JP96/03635 Sec. 371 Date Nov. 19, 1997 Sec. 102(e) Date Nov. 19, 1997 PCT Filed Dec. 12, 1996 PCT Pub. No. WO97/48766 PCT Pub. Date Dec. 24, 1997(i) A starting rubber (A) comprising a terminal-modified and/or coupled diene rubber and having an average glass transition temperature TgA ( DEG C.) is mixed with a specific amount of the reinforcing agent are mixed at a temperature of at least 135 DEG C., followed by adding a starting rubber (B) comprising a terminal unmodified diene rubber and having a specific average glass transition temperature TgB ( DEG C.), and the remaining reinforcing agent and a softening agent; (ii) a starting diene rubber (A') having a specific weight average molecular weight Mw(A') and average glass transition temperature TgA' ( DEG C.) is contacted with a reinforcing agent, followed by adding a starting diene rubber (B') having a specific weight average molecular weight Mw(B) and average glass transition temperature TgB' ( DEG C.), and a softening agent to produce a rubber composition; or (iii) 100 parts by weight of a starting rubber comprising a starting rubber (A'') comprising 20 to 100% by weight of a terminal-modified and/or coupled diene rubber and a starting rubber (B'') comprising a terminal-unmodified and/or uncoupled rubber are mixed with a specific carbon black (X) in specific amounts at a temperature of at least 135 DEG C., followed by adding the starting rubber (B'') and the remaining carbon black and a softening agent. |