PURPOSE: To enhance ballistic resistance, impact resistance, surface appearance and durability by heat-treating an aliphatic polyamide filament fabric and preheating this heat-treated fabric and an aromatic polyamide filament fabric before impregnating both fabrics with a thermoplastic resin soln.

CONSTITUTION: Aliphatic polyamide filaments of 250-1500 denier are used to weave a fabric of which the warp and weft yarn densities are about 11.81-39.38/cm and this fabric is heat-treated at 100-200°C for 1-10 min. Aromatic polyamide filaments of 1000-3000 denier are used to weave a fabric of which the warp and weft yarn densities are about 11.81-39.38/cm. Two kinds of these fabrics are preheated at 50-120°C for 1-10 min to be impregnated with a thermoplastic resin soln. prepared from at least one of a phenol-formaldehyde resin, an epoxy resin, a vinyl ester and an unsaturated polyester, polyvinyl butyral and methanol and the impregnated fabrics are dried at 50-150°C for 1-10 min to produce a prepreg.