acrylate or methacrylate in the copolymer is at least 2 percent by weight component a can have any form such as a solution an emulsion a paste a latex a powder or a solid form organopolysiloxanes used as component b in the compositions of this invention are expressed by the formula str2 in this formula each r represents a substituted or unsubstituted monovalent hydrocarbon radical such as alkyl radicals such as methyl ethyl propyl octyl and tridecyl cycloaliphatic radicals such as the cyclohexyl radical alkenyl radicals such as vinyl and allyl radicals aryl radicals such as the phenyl radical or said monovalent hydrocarbon radicals in which hydrogen atoms are replaced with halogen atoms or cyano radicals it is not always necessary that all the r groups in a single molecule are identical r 39 represents divalent hydrocarbon radicals such as alkylene radicals such as ch 2 ch 2 ch 2 ch 2 ch 2 ch 2 ch 3 ch ch 2 ch ch 3 ch 2 and ch 2 4 or alkylene arylene radicals such as ch 2 2 c 6 h 4 or ch 2 4 ch 2 ch ch 2 c 6 h 5 r 34 represents an alkyl radical such as methyl ethyl propyl decyl and octadecyl a represents r or r 39 ocor 34 radicals in the formula for component b m and n are 0.