| abstract |
A composition contains an organopolysiloxane having the following average chemical structure: X3SiO-SiR2-R'-(R2SiO)x-R2Si-[Rb-(R2SiO)y-R2Si-Rb'-(R2SiO)z-R2Si]m-R'-R2SiO-SiX3; where X is -OSiR2-R'-R2SiO-R2Si-R"-A; R is an alkyl group having from 2 to 6 carbons and aryl groups; R', R", Rb and Rb' are divalent hydrocarbon groups comprising a chain of 2 to 6 methylene units; A is acrylate, methacrylate or trialkoxysilyl; provided that, on average, 60 to 90 mole-percent of the A groups are acrylate and methacrylate; Subscript m has an average value in a range of zero to 10; Subscripts x, y and z each has an average value in a range of zero to 1200; and provided that the average values of m, x, y and z are such that the sum of the average values for x, y and z is in a range of 300-1200 and the molar ratio of methylene units to siloxane units is less than 0.15. |