Patent ID: 8071697
Filing Date: 2011-12-06
Classification: B29C,B29D,B29K,B29L,C08L

Abstract:
1. A composition comprising: (A) 100 parts by weight of an organopolysiloxane resin represented by average compositional formula where each R 1 is independently an alkenyl group having 2 to 10 carbon atoms, each R 2 is independently a substituted or unsubstituted monovalent hydrocarbon group other than R 1 , with the proviso that at least 50 mole % of R 2 comprise phenyl groups, subscript “a” has a value ranging from 0.09 to 0.16, and subscript “b” has a value ranging from 1.00 to 1.20; with the provisos that (i) the organopolysiloxane resin comprises alkenyl groups and phenyl groups and (ii) the organopolysiloxane resin has a weight-average molecular weight equal to or exceeding 3000 with polystyrene as reference and determined by gel chromatography; (B) 10 to 50 parts by weight of an organooligosiloxane represented by average compositional formula where each R 3 is independently an alkenyl group having 2 to 10 carbon atoms, each R 4 is independently a substituted or unsubstituted monovalent hydrocarbon group other than R 3 , with the proviso that at least 10 mole % of R 4 comprise phenyl groups; subscript “c” has a value ranging from 0.60 to 0.80, and subscript “d” has a value ranging from 1.50 to 2.10; with the proviso that the organooligosiloxane comprises alkenyl groups and phenyl groups; (C) 20 to 100 parts by weight of an organohydrogenoligosiloxane or organohydrogenpolysiloxane represented by average compositional formula where each R 5 is independently a substituted or unsubstituted monovalent or non-substituted monovalent hydrocarbon group other than alkenyl groups, with the proviso that at least 20 mole % of R 5 comprise phenyl groups; subscript “e” has a value ranging from 0.35 to 0.65, and subscript “f” has a value ranging from 0.90 to 1.70; (D) a catalytic quantity of an addition-reaction catalyst; and (E) 0.2 to 2 weight % of a mold release agent; where the composition is curable to form an article having a hardness of 60 to 100 at 25° C. and 40 to 100 at 150° C. as measured by ASTM D2240-86.