Abstract What are designated as ''''composite'''' fiber reinforced polymer (or plastic) articles or structures can be manufactured using what are termed ''''preformed'''' articles and ''''intermediate'''' articles. Such a preformed article may be created by compressing in a chilled die a mixture of reinforcing fibers and a hot melt polymer composition at a temperature at which the composition will flow but below the temperature at which the composition will set up or cure, removing the compressed article from the die and storing it at a low temperature at which it is dimensionally stable until it is ready to be used in a final manufactured article or structure. Such an intermediate article can be manufactured by winding a fiber sheet impregnated with a hot melt polymer composition on a mandrel while subjecting the sheet to pressure and to heat sufficient to cause the composition to flow but not to cure so as to form a dense structure. In the manufacture of a composite article, one or more of the preformed articles are located on an intermediate article and the resultant assembly is cured in a die under heat and pressure. Such preformed and intermediate articles can be cured separately or in contact with other articles by the application of heat and pressure.
forming an intermediate article by, winding a fiber sheet impregnated with a hot melt polymer composition to be used in the intermediate article on a mandrel while subjecting said sheet to heat and pressure as it is wound on said mandrel, said heat being sufficient so as to cause said composition to flow under the pressure applied, said heat being insufficient to cause said composition to cure, such pressure being sufficient to cause the windings of said sheet on said mandrel to be compacted together to at least 95 percent of the theoretical density of said intermediate article, and
Claim 2
Dependent Claim
138 words
A process as claimed in claim 1 wherein: said mixture contains from about 20 to about 80 percent by weight of said reinforcing fibers and from about 20 to about 80 percent by weight of said polymer composition, said compressing is carried out while said mixture is at a temperature of from about 140* to about 160* F., said cooling is partially accomplished by holding said mixture in contact with a mold until said mixture becomes rigid and coherent, said maintaining is carried out at a temperature of from about -10* to about -15* F., said winding is carried out with said sheet at a temperature of from about 140* to about 160* F. while said mandrel is at a temperature of from about 180* to 200* F., said mandrel serving to heat said sheet during said winding.
Claim 3
Dependent Claim
93 words
locating said mandrel containing said intermediate article and said preform with the polymer compositions in each in an uncured state with said preform against said intermediate article while said preform is sufficiently cold so as to be rigid, coherent and dimensionally stable in a mold and applying heat and pressure to said intermediate article and said preform so as to cure said polymer composition in said preform and said intermediate article into a unitary structure and so as to increase the densities of said preform and said intermediate article in said unitary structure.