Organofunctional polysiloxanes for modifying the surface of finely divided particles

Claim 1

A coating material for modifying a surface of a finely divided pigment, filler or glass fiber wherein the coating material comprises a polyorganosiloxane with ester groups, epoxide groups or both linked to silicon atoms over carbon atoms and having a general formula ##STR9## wherein R 1 is an alkyl group with 1 to 18 carbon atoms, at least 90% of the R 1 groups being CH 3 groups; R 2 to the extent of 50 to 99% is identical with the R 1 groups and, to the extent of 1 to 50%, is identical with the R 3 and R 4 groups; R 3 is a group of the formula --(CH 2 ) n --CO--OR 5 , and/or ##STR10## and/or ##STR11## R 5 is an alkyl group with 1 to 4 carbon atoms; n is a number from 3 to 20; R 4 is a group of formula ##STR12## the ratio of R 3 groups to R 4 groups being 1:25 to 10:1, with the proviso that there must be at least one R 3 group and at least one R 4 in the average molecule; a is a number from 1 to 500; and b is a number from 0 to 10.