A process for the treatment of glass yarn in which the yarn is impregnated with a low viscosity solution of a thermosetting binder in an organic solvent, the viscosity of said solution being not greater than 50 centipoise (=0.05 Pascal seconds) at 25.degree. C.; solvent is then evaporated from the impregnated yarn; the yarn is further impregnated with a high viscosity solution of a thermosetting binder in an organic solvent; and solvent is again evaporated from the impregnated yarn. The process improves the properties of the glass yarn when used in the manufacture of glass reinforced composites.
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.
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.
