US Patent 7395654 Reinforcing composite yarn and production therefor

A composite yarn having a high reinforcing effect on a matrix material to be reinforced is a paralleled yarn of at least one substantially non-twisted multifilament yarn having a tensile strength of 13 cN/dtex or more and an initial modulus of 300 cN/dtex or more with at least one substantially non-twisted staple fiber yarn having a staple fiber fraction (1) having a fiber length of 1.5 times or more the average fiber length of the staple fibers and another fraction (2) having a fiber length of 0.5 time or less the average fiber length, in which a portion of the staple fibers in the staple fiber yarn winds around the periphery of the paralleled composite yarn to thereby bind the multifilament yarn and the staple fiber yarn substantially into a composite yarn without twisting the composite yarn.