Patent ID: 6703120
Filing Date: 2004-03-09
Classification: B01L,C08L,C09J,Y10T

Abstract:
An adhesive prepared from components comprising:(a) a polydiorganosiloxane having the general formula R1R2SiO(R2SiO)nSiR2R1 and a number average molecular weight of at least 20,000, wherein each R is independently a monovalent hydrocarbon group, each R1 is independently an alkenyl group, and n is an integer; (b) a polydiorganosiloxane having the general formula R1R2SiO(R2SiO)m(R1RSiO)nSiR2R1 and a number average molecular weight of less than 20,000, wherein each R and R1 is independently a monovalent hydrocarbon group at least two R1 groups are alkenyl groups, and m and n are integers the sum of which provide an alkenyl equivalent weight of about 250 to about 10,000; (c) an organopolysiloxane MQ resin which contains (R2)3SiO1/2 units and SiO2 units in a molar ratio in the range of 0.6:1 to 1:1, wherein each R2 is independently selected from the group of alkyl groups, alkenyl groups, or hydroxyl groups, wherein at least 95 mole percent of all R2 groups are methyl groups; (d) an organohydrogenpolysiloxane free of aliphatic unsaturation having an average of at least 2 silicon-bonded hydrogen atoms in each molecule, in a quantity sufficient to provide from 1 to 40 silicon-bonded hydrogen atoms per alkenyl group in components (a) through (c); and (e) a Group VIIB-containing catalyst in a quantity sufficient to provide 0.1 to 1,000 weight parts Group VIIIB metal for each one million weight parts of the combined quantity of components (a) through (d); wherein when the adhesive is disposed on a propylene/ethylene copolymer backing at a coating weight of 0.8 grams/154.8 cm2 and adhered to a polypropylene plate displays a 180Â° peel force of at least about 5 N/dm when measured at 30.5 cm/minute and room temperature.