this invention relates to an improved flexible towpreg and a method of production therefor . the improved flexible towpreg comprises a plurality of towpreg plies which comprise reinforcing filaments and matrix forming material ; the reinforcing filaments being substantially wetout by the matrix forming material such that the towpreg plies are substantially void - free composite articles , and the towpreg plies having an average thickness less than about 100 microns . the method of production for the improved flexible towpreg comprises the steps of spreading the reinforcing filaments to expose individually substantially all of the reinforcing filaments ; coating the reinforcing filaments with the matrix forming material in a manner causing interfacial adhesion of the matrix forming material to the reinforcing filaments ; forming the towpreg plies by heating the matrix forming material contacting the reinforcing filaments until the matrix forming material liquifies and coats the reinforcing filaments ; and cooling the towpreg plies in a manner such that substantial cohesion between neighboring towpreg plies is prevented until the matrix forming material solidifies .