A method for the production of the form of bodies and prefabricated, dry, flexible film for carrying out this method

摘要

1297462 Mould lining FERRO CORP 27 May 1971 [3 June 1970] 17481/71 Heading B5N [Also in Division C3] A flexible sheet material suitable for lining the inside of a mould to form the outer surface of a moulded article has a thickness of from 10 to 20 mil. and comprises a layer of a curable epoxy resin or unsaturated alkyd resin composition and a reinforcing fibrous layer wherein the said composition is derived from a mixture comprising 100 parts by weight of epoxy resin or alkyd resin, 50 to 85 parts polydibasic acid polyanhydride, 10 to 25 parts fumed alumina and 0À5 to 5 parts of accelerator wherein the epoxy resin has the formula wherein x is 0 or 1; n has an average value of at least 0À5; R, RSP1/SP, RSP11/SP being hydrogen or methyl, with no more than one R, RSP1/SP, RSP11/SP being methyl, and when x is I both Rs, RSP1/SPs and RSP11/SPs are hydrogen; # is the divalent aromatic radical derived from bisphenol, dihydroxy diphenyl, dihydroxydiphenylmethane, resorcinol and hydroquinone by removal of two hydroxy groups therefrom; RSP4/SP is hydrogen or an alkyl group of from one to 5 carbon atoms; nSP11/SP is an integer of at least 4; Y is hydrogen or an epoxy alkyl radical of the formula there being at least three of said epoxy alkyl radicals per polymer molecule; (b) the polydibasic acid polyanhydride has the formula wherein xSP1/SP is an integer of from 5 to 10 and nSP1/SP is an integer of at least 4; (c) the accelerator is a tertiary amine or stannous alkanoate having from 5 to 12 carbon atoms and (d) the unsaturated alkyd resin has a molecular weight of from 800 to 3000 and an acid number of from 10 to 40. The fibrous reinforcement may be woven or non-woven and may be impregnated with the resin used in the resinous layer. The resin is suitably cast as a film on a release paper and the reinforcing fibre layer is placed thereon and pressure is suitably applied by a set of rollers. In Example 1 the liner is employed to provide a smooth surface on a fibreglass reinforced epoxy resin.