Mechanism of Stain Blockers for Nylon Substrate.

The stain-resistance of nylon 6 substrate treated with aqueous polymethacrylic acid solutions (PMAA soln.) was investigated. The stain-resistance increased only when nylon 6 film was treated with acidic PMAA soln. at high temperature (naturally at more than Tg of nylon 6). A dynamic contact angle of water measurement revealed that hydrophilic groups including amino end groups of nylon 6 tend to diffuse on the outer surface of nylon 6 by hot water (temperature>Tg). In addition the stain-resistance was found to have linear correlation with deposited PMAA on nylon 6. All these data denoted that an interaction between PMAA and cationized amino end groups might give a good stain-resistance to nylon 6. We confirmed that the treatment by PMAA soln. with pH 2 produced the nylon 6 having cleaning-durable high stain-resistance. From these data a tentative and possible stain-resistant mechanism was proposed.