To provide a clay-loaded rubber compsn. which has a low viscosity and improved processibility and productivity without detriment to the physical properties of its vulcanizate, such as hardness and elongation at break, by compounding a raw material rubber with clay and a polysiloxane.
A polysiloxane having Si-H groups is reacted with an alcohol or a carboxylic acid in the presence of a catalyst to give a polysiloxane which has alkoxysilyl groups represented by the formula: ≡SiOR1 [wherein R1 is an (un)substd. 1-18C monovalent hydrocarbon group or an org. group having an ether bond] or acyloxysilyl groups represented by the formula: ≡Si-OCOR2 (wherein R2 is H or a 1-21C hydrocarbon group) and an average degree of polymn. of 3-1,000. Then, 100 pts.wt. raw material rubber is compounded with 5-100 pts.wt. clay and the above-obtd. polysiloxane in an amt. of 40wt.% or lower thereof.
YATSUYANAGI CHIKASHI
ISHIKAWA KAZUNORI
