The anti-redeposition action of sodium carboxy-methyl cellulose (CMC) and polyvinyl alcohol (PVA) in washing process was investigated. CMC having various degree of polymerization (70_??_1, 000) or PVA (_??_=500_??_1, 800) with various degrees of substitution of acethyl group prepared by hydrolysis of polyvinyl acetate (78.5_??_99.4mol%) was added as a builder to the model soiling bath in which carbon black was dispersed in sodium dodecyl sulfate aqueous solution. The degrees of anti-redeposition effect of cotton and nylon fabrics and nylon film were measured by optical reflctance method after the treatment in the soiling bath.
The addition of CMC to the soiling bath prevents soil deposition on cotton fabric at the concentrations more than 1×10^-3%, while it shows no obvious effect on nylon fabric.
When PVA is used, soil deposition on cotton and nylon fabrics and nylon film is prevented. By the addition of any PVA more than 1×10^-4%, the cotton fabric is slightly soiled. In the case of nylon fabric, the soil prevention effect becomes more remarkable with the increased degree of hydrolysis of PVA. In the degrees of hydrolysis from 78.5% to 81.5%, low molecular weight PVA is more effective for the prevention of soil deposition on nylon fabric than high molecular weight PVA.
It is concluded from above results that PVA is effective as an anti-redeposition agent for cotton and nylon, and that.PVA highly hydrolyzed has a remarkable effect for soil prevention.