ON SOIL DEPOSITION PREVENTION EFFECT OF POLYVINYL ALCOHOL

Anti-redeposition action of polyvinyl alcohol (PVA) in washing process was investigated. PVA of various degrees of acetate residue hydrolysed from polyvinyl acetate was added as a builder to soiling bath containing carbon black dispersed in aqueous solution of sodium dodecyl sulphate (SDS). Degree of soil deposition on cotton, nylon, vinylon, polyester and polyacryl nitril fabric was measured by optical reflectance method after they were treated in the soiling bath.It was found that the addition of any sample of PVA to the soiling bath prevented soil deposition on all fabrics used in this experiment. Soil prevention effect became more remarkable with decreasing of degree of acetate residue. The soil prevention effect of high degree of acetate residue (18.5-21.5mol%) in 0.2% SDS aqueous solution was less than that in 0.1% SDS aqueous solution. It seemed that this was due to complex formation between SDS and PVA. Comparing the soil prevention effect of PVA deposited on the fabrics with that of PVA in the soiling bath, it was thought that the latter alone is effective for soil prevention. It is deduced that PVA molecules were adsorbed on carbon black particles to have the soil prevention effect.