. . "R???NH???CH2???CH(R1)???CH2???Si(R1)x(OR2)(3-x)???(Ib) wherein in formulae (Ia) and (Ib), R is a linear or branched alkyl group having 1 to 18 C atoms, R1 is a methyl group, R2 is a methyl or ethyl group and x is 0 or 1," . .