GB1339507A - Curable fluoroelastomer compositions - Google Patents

Abstract

1339507 Curable fluoroelastomer compositions E I DU PONT DE NEMOURS & CO 28 April 1971 [28 April 1970 22 March 1971] 11927/71 Addition to 1300782 Heading C3P A curable fluoroelastomeric copolymer composition as defined in claim 1 of Specification 1,300,782 wherein: (A) (i) the dihydroxylic aromatic compound is a dihydroxybenzene, dihydroxynaphthalene or dihydroxyanthracene substituted with one or more substituents selected from bromine, carboxyl and acyl or (ii) the dihydroxylic aromatic compound is a bisphenol of the general formula wherein (a) at least one of the hydroxyl groups is not para to the group A and x is 0 or 1; and/or (b) the group A is selected from difunctional, aliphatic, cycloaliphatic or aromatic groups having 11 to 13 carbon atoms, thio, oxy, carbonyl, sulphinyl or sulphonyl groups; or (iii) the dihydroxylic aromatic compound is replaced at least in part by a tri- or tetrahydroxy-substituted benzene, naphthalene or anthracene, or by a bisphenol of the general formula wherein A is a difunctional aliphatic, cycloaliphatic or aromatic group of 1 to 13 carbon atoms, or a thio, oxy, carbonyl, sulphinyl or sulphonyl group; and x is 0 or 1; and/or (B) the divalent metal oxide is replaced at least in part by a divalent metal hydroxide or a mixture of a divalent metal oxide and/or hydroxide with a metal salt of a weak acid, the salt not being barium carbonate, calcium carbonate or calcium silicate when a divalent metal oxide alone is employed. In the examples the compositions comprise a vinylidene fluoride/hexafluoropropylene copolymer, magnesium oxide, calcium hydroxide, carbon black, 2-dodecyl-1,1,3,3- tetramethylguanidine absorbed on silica, hydroquinone and 4,4<SP>1</SP>-dihydroxy diphenyl sulphone and are press-cured and post-cured.