Method of preparing fillers which are modified by organosilicon compounds, the products thus obtained and their use.

摘要

Surface modification of natural or synthetic oxidic or silicate fillers (I) comprises using one or more organosilicon cpds. of formula: (R'n(RO)3-nSi-(Alc)m-(Ar)p)q(B) (I). In (I), B = -SCN (when q = 1) or -Sx- (when q = 2); R and R' = 1-4C alkyl, phenyl in which every R and R' is identical or different, R = 1-4C-alkyl-1-4C-alkoxy gp.; n = 0, 1 or 2; alc = bivalent, linear or branched 1-6C hydrocarbon; m = 0 or 1; Ar = 6-12C arylene gp.; p = 0 or 1 (p+m does not equal 0); x = 2-8. The novelty is that: (a) at least one organosilicon cpd. is intensively mixed with the filler at temps. less than 60 deg.C in a concn. of up to 3.5 x 10 power (-6) mol. trialkoxysilyl gps. on a square meter of filler surface; (b) followed by hydrophobising the homogenised mixt. in a preheated mixer, tempered bed or another suitable heated reaction vessel at temps. larger than 60 deg.C.