PURPOSE: To obtain a rubber composite, which is excellent in molding process, by combining natural rubber with rubber reinforcing constituent in which a polymer and vulcanizable rubber are grafted with each other via primary condensation of phenol-formaldehyde resin.
CONSTITUTION: Natural rubber (100pts.wt.), ageing preventing agents (1.0pt.wt.), and 6-nylon (50pts.wt.) are thrown into a Banbury mixer, which is kept at 150°C, and kneaded for thorough blend for 4min. During this time, the temperature in the mixer rises up to 230°C, and the 6-nylon is melted. Next, primary condensation (2.25pts.wt.) of novolak-type phenol-formaldehyde is added and kneaded for 7min. Further, hexametylene-tetramine (0.225pts.wt.) is thrown into the mixer and kneaded for 2.5min for graft reaction. Then, the whole things are dumped. The thus obtained kneaded mixture is extruded from an extruder and elongated to the graft ratio of 9. Besides, this elongated substance is rolled to about 10 times in length through the roll clearance of 0.2mm. With this, a reinforced rubber composite can be obtained.
TANIBUCHI TERUO
YAMAMOTO SHINJI
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