Carbon fiber multifilamentary tow which is particularly suited for

Abstract

An improved multifilamentary tow of carbon fibers is provided which possesses a novel physical configuration that better enables it to undergo impregnation with a matrix-forming resin to form quality composite articles. The individual filaments of the tow are randomly decollimated and commingled with numerous filament cross-over points throughout the length of the multifilamentary tow in order to create a multitude of interstices between adjacent filaments which are well adapted to receive and retain a matrix-forming resin as evidenced by the ability of the filaments when subjected to the flaring test described herein to resist lateral expansion to a width that is as much as three times the original width. The tow commonly comprises approximately 1,000 to 50,000 filaments. Also, the filaments of the tow are substantially continuous and contain at least 70 percent carbon by weight (preferably at least 90 percent carbon by weight). In a preferred embodiment wherein the resistance to lateral expansion is the greatest, the multifilamentary bundles have been found to be capable of being readily woven with no significant productivity loss to form a quality reinforcing fabric while free of a protective size, such as that which has heretofore been required while weaving carbonaceous multifilamentary yarn bundles of the prior art.