Modified fibers for use in the formation of thermoplastic fiber-reinforced composite articles and process

摘要

A surface-modified fibrous material is provided for incorporation in a thermoplastic matrix to form a fiber-reinforced composite article. Good binding between the fibrous material and the thermoplastic matrix is achieved through the presence of finely roughened surfaces on the fibers of nanoparticles of an inorganic material. Such nanoparticles are provided from an alkaline aqueous size composition containing the nanoparticles dispersed therein (as described). The fibrous material may be provided in continuous or discontinuous form. In a preferred embodiment glass fibers are initially provided in continuous form followed by cutting into discontinuous lengths and drying with the retention of the nanoparticles on the surfaces of the fibers. The surface-roughened fibrous material is incorporated in a thermoplastic matrix as fibrous reinforcement with the application of heat whereby the thermoplastic matrix is rendered melt processable. In preferred embodiments injection or compression molding is utilized. Improved long-fiber thermoplastics also may be formed to advantage.

主权项

1. A process for forming a fiber-reinforced thermoplastic composite article, the process comprising:
(a) applying as a coating to the surface of glass fibers an alkaline aqueous size composition comprising:
a dispersion of nanoparticles of an inorganic material,a polymeric film-former, anda combination of silanes comprising at least one reactive silane and at least one non-reactive silane, wherein the nanoparticles are in a concentration of about 10 to 40 percent by weight based on the weight of total sizing solids in the size composition, (b) drying said coating present on said glass fibers to aid in adherence of the nanoparticles onto said glass fibers and provide a roughened surface on said glass fibers, (c) incorporating said glass fibers bearing said roughened surface in a thermoplastic matrix as fibrous reinforcement with the application of heat whereby said thermoplastic matrix is rendered melt processable, wherein the at least one reactive silane couples the glass fibers to the thermoplastic matrix, and (d) forming a fiber-reinforced composite article with the reinforced thermoplastic matrix, wherein the composite comprises a Notched Izod impact strength that is greater than a composite formed without the nanoparticles.