| abstract |
Siliceous fillers (I), consisting of particles of the usual size, have a carbonaceous surface coating (II), pref. with about the same compsn. as the C black used in the rubber industry. Claims cover the use of the filler in a polymer compsn. pref. contg. a curable unsatd. polymer, esp. a butadiene rubber , e.g. butadiene-styrene or butadiene-acrylonitrile rubber. It is generally suitable for filling natural and synthetic rubbers. The filler combines the properties of (I) with high compatibility with organic polymers. (II) is pref. produced by catalytic cracking of an organic cpd. (pref. a hydrocarbon) on (I), which has a particle size of 100 mu m and a BET surface area of 5-300 m2/g. In an example 200 angstroms SiO2 particles (225 m2/g) were fluidised in C3H6 at 400-500 degrees C, giving a black mobile powder contg. 5.5% C, with an I2 no. of 5.5 and surface area of 177 m2/g, used for filling an SBR blend. |