Abstract: The disclosure relates to the production of multi-ply battery separators utilizing mats of melt-blown, randomly laid, self-bonded thermoplastic resin fibers. The process involves the production of at least three separate plies of self-bonded, melt-blown thermoplastic fibers, which are joined in the absence of separate adhesive materials to form a cohesive, multi-ply material. The multi-ply material comprises an internal structure having fiber size, porosity and other characteristics particularly suitable for use in lead-acid battery separator application. The outer plies are formed to have characteristics more suitable for strength and abrasion resistance. In the process of the invention, the several plies are separately formed by melt-blowing techniques, in themselves known, and the several plies are joined in the presence of heat and/or heat and pressure, forming a multi-ply structure entirely free of external adhesive material.