| 摘要 |
<p>1348862 Thermosetting resin impregnated laminates SHELL INTERNATIONALE RESEARCH MAATSCHAPPIJ NV 24 April 1972 18890/72 Addition to 1266097 Heading B5N An article impregnated with thermosetting resin is produced by impregnating a felt pad or sheet having an open-cell foam structure, e.g. flexible polyurethane foam sheet, with a curable thermosetting resin, e.g. an epoxy resin, applying a layer of fibrous reinforcing material, e.g. a glass fibre mat, to a side of the impregnated felt pad or foam sheet, compressing the felt pad or foam sheet and fibrous reinforcing layer to the extent that resin is expelled from the pad or sheet into the fibrous reinforcing layer to impregnate this layer with resin throughout its thickness and allowing the resin in the pad or sheet and layer to cure whilst maintaining the compression, gas pressure being generated in the felt pad or cells of the impregnated foam sheet to promote the expulsion of resin from the felt pad or foam sheet into the fibrous reinforcing layer. The gas pressure may be generated by means of an agent capable of releasing gas when heated or by chemical reaction. Suitable gas generating agents which may be mixed with the liquid resin composition prior to impregnation of the felt pad or foam sheet are liquid hydrocarbons, e.g. pentane, a composition releasing carbon dioxide or nitrogen by chemical reaction of its components or by reaction with the curing agent present in the resin, e.g. azo-isobutyronitrile, or water in cases where curing is effected at temperatures above 100‹ C.</p> |
