Patent ID: 8119760
Filing Date: 2012-02-21
Classification: C08K,C08L

Abstract:
1. A method of improving an acid resistance of a gel, said method comprising: preparing a curable perfluoropolymer composition comprising (A) a linear perfluoropolyether compound containing at least two alkenyl groups per molecule, having a perfluoropolyether structure comprising recurring units —C (B-2) an organosilicon compound containing at least two silicon atom-bonded hydrogen atoms per molecule and at least one perfluoroalkyl group or perfluoropolyether substituent group per molecule wherein all silicon atom-bonded hydrogen atoms form H—SiR wherein i and j are 0 or 1, excluding the case where both i and j are 0, in the case where either one of i and j is 0 and the other is 1, Z is -Q-Rf 3 , Q is a divalent hydrocarbon group of 1 to 15 carbon atoms which may contain an ether bond, Rf 3 is a monovalent perfluoroalkyl or perfluorooxyalkyl group, M is a group of formula (i): R 6 is a monovalent hydrocarbon group of 1 to 20 carbon atoms, and g is an integér of 1 to 3, in the case where both i and j are 1, Z is, —Rf′— or -Q-Rf′-Q-, Q is as defined above, Rf′ is a divalent perfluoroalkylene or perfluorooxyalkylene group, M is a group of the formula (ii) and/or a group of the formula (iii): wherein Rf 4 is monovalent perfluoroalkyl or perfluoropolyether group and Q and g are as defined above, with the proviso that there are present at least two groups of formula (ii) per molecule, R 5 is a monovalent hydrocarbon group of 1 to 20 carbon atoms, t is 1, 2 or 3, and u is 0, 1, 2 or 3, (D) a hydrosilylation catalyst, and (E) a polyfluoromonoalkenyl compound containing one alkenyl group per molecule and having a perfluoropolyether structure in its backbone, and curing said curable perfluoropolyether composition, thereby forming a gel having a weight gain of up to 6% when saturated in gasoline at 23° C. and a weight gain of up to 8% when immersed in concentrated sulfuric acid (98%) at 23° C. for 3 days.