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An improved multifilamentary fibrous material is formed having particles of a matrix-forming thermoplastic polymer substantially uniformly dispersed among adjoining filaments in the absence of fusion bonding. The polymer particles initially are dispersed in an aqueous medium containing an effective

An improved multifilamentary fibrous material is formed having particles of a matrix-forming thermoplastic polymer substantially uniformly dispersed among adjoining filaments in the absence of fusion bonding. The polymer particles initially are dispersed in an aqueous medium containing an effective amount of a dissolved polymeric binding agent and the viscosity of the medium subsequently is substantially increased to at least 50,000 cps. to form a gelled impregnation bath having a plastic flow characteristic with shear-thinning behavior wherein the polymer particles are substantially uniformly suspended. The resulting impregnation bath is caused to flow between the adjoining filaments of the multifilamentary fibrous material with a concomitant viscosity reduction which aids in the incorporation of the polymer particles. The concentration of the aqueous medium in the product is controlled to yield a uniform, handleable, drapable, tacky, and highly stable product. Upon the application of heat and pressure the improved product can be transformed into a fiber-reinforced composite article wherein the solid particles form the matrix phase.

대표청구항 ▼

A method for the production of an improved fibrous material suitable for the formation of a substantially void-free composite article comprising a plurality of adjoining substantially parallel reinforcing filaments in association with a matrix-forming thermoplastic polymer comprising: (a) preparing

A method for the production of an improved fibrous material suitable for the formation of a substantially void-free composite article comprising a plurality of adjoining substantially parallel reinforcing filaments in association with a matrix-forming thermoplastic polymer comprising: (a) preparing a dispersion of solid particles of a thermoplastic polymer in an aqueous medium which contains an effective amount of a dissolved polymeric binding agent, (b) substantially increasing the viscosity of said dispersion to form an improved impregnation bath whereby the viscosity of the resulting bath becomes at least 50,000 cps. and said impregnation bath has a plastic flow characteristic with shear-thinning behavior which is sufficient to substantially uniformly suspend said particulate thermoplastic polymer within said bath, (c) impregnating said adjoining substantially parallel reinforcing filaments with said bath under conditions wherein said bath is caused to flow between said adjoining filaments by the application of work wherein said bath flow inherently results in a reduction of the viscosity of said bath which aids in the incorporation of said particulate thermoplastic polymer between adjoining filaments, and (d) controlling the content of said aqueous medium in the resulting fibrous material to provide a product having said particles of matrix-forming thermoplastic polymer substantially uniformly dispersed between adjoining filaments in the absence of fusion bonding which inherently (1) is drapable and tacky at ambient conditions, (2) is handleable without segregation of said particles within the fibrous material, and (3) which upon the application of heat and pressure can be transformed into a substantially void-free fiber-reinforced composite article of a predetermined configuration wherein said solid particles form the matrix phase.