Enhanced adhesion of steel filaments to rubber via plasma etching and plasma-polymerized coatings

Zinc-plated steel filaments were coated with RF plasma polymers of acetylen e or butadiene in order to enhance adhesion to rubber compounds. Plasma pol ymerization was carried out as a function of the plasma power, deposition t ime, and gas pressure. In order to maximize adhesion, argon plasma etching was performed and carrier gases such as argon, nitrogen, and oxygen were us ed. Plasma polymer coatings were characterized by FT-LR, Alpha-Step, and a dynamic contact angle analyzer. The adhesion of steel filaments was evaluat ed via a tire cord adhesion test (TCAT). The best results were obtained fro m a combined process involving argon etching (90 W, 10 min, 30 mTorr) and a cetylene plasma polymer coating (10 W, 30 s, 30 mTorr) with argon carrier g as (25/5, acetylene/argon). These samples exhibited a pull-out force of 285 N, which is comparable to that from the brass-plated steel filament (290 N ).