Method of making a hybrid prepreg

Abstract

The present invention relates to a hybrid prepreg having reinforcing carbon fibers and foreign fibers. The carbon fibers have a diameter ranging from 5-30 microns and are unidirectionally arranged. The foreign fibers are composed either of single monofilaments having a diameter ranging from between about 50-150 microns or of strands formed by bundling together a plurality of single monofilaments having a diameter ranging from between about 5-50 microns. If strands are employed, they have a conversion diameter (D.sub.0) which is less than about 500 microns. The conversion diameter (D.sub.0) is represented by the following equation: ##EQU1## wherein n is the number of monofilaments used in forming the strand, and wherein d is the diameter of these monofilaments. Examples of foreign fibers which can be used when practicing this invention include boron fibers, metal fibers and organic fibers. These foreign fibers are spaced at fixed intervals, arranged in the same direction as the direction of the reinforcing carbon fibers, and positioned approximately at or near the center of the resulting prepreg. The prepreg prepared in accordance with the present invention also includes a thermosetting matrix resin in which the reinforcing carbon fibers and the foreign fibers are impregnated.

Dependencies are inferred from the claim text.