| 摘要 |
941,481. Laminates. SOC. ANON. DES USINES CHAUSSON. Nov. 9, 1959 [Dec. 3, 1958], No. 37904/59. Heading B5N. [Also in Division C3] A method of manufacturing unsaturated polyester resin sheets reinforced with natural or man-made fibre or fabric, e.g. glass fibre, and capable of being shaped mechanically and of being laminated, comprises (a) treating a permeable layer of reinforcing material with a polymerization initiator comprising a salt of a polyvalent metal, (b) agitating, and applying to the layer, a catalysed polyester resin which has been partially polymerized to a thixotropic gel, (c) subjecting one or both faces of the treated layer to the action of heat and/or a polymerization accelerator to form a thin, more fully polymerized, surface layer. The method is a modification of that described and claimed in Specification 938,403 wherein, in step (b), the catalysed polyester is gelled after application to the layer. In embodiments the gelled polyester may be diluted with ungelled polyester before application to the layer, or layers impregnated with the gelled polyester may be laminated with layers impregnated with the ungelled polyester and the laminate subjected to the surface treatment. The polyester may contain an inhibitor, e.g. 4-methyl-2: 6-di.t.-butylphenol, to extend the gel life, and a filler, e.g. calcium carbonate. The polymerization accelerator may be a mono- or di-alkyl aniline and may be mixed with a lubricant or mould-release agent, e.g. a mixture of mono- and di-alkyl phosphates. In examples the polymerization initiator is stannous chloride and the polyester is derived from ethylene glycol, maleic and phthalic anhydrides and adipic acid and is catalysed with benzoyl peroxide. The solvent comonomer is methylstyrene. |
