Alkyl Alcohols as Defoamers to Remove Foam Generated by Partially Alcoholyzed Polyvinyl Alcohol for Warp Sizing

Alkyl alcohols were evaluated as defoamers to eliminate the foam produced by partially alcoholyzed polyvinyl alcohol (PAPVA) according to their defoaming ability and actual influence on adhesion to fibers, film properties, and desizability. The alcohols considered included 1-pentanol, 1-hexanol, 1-heptanol, 1-octanol, 1-nonanol, 1-decanol, isooctyl alcohol, and 2-octanol. The impact of alkyl alcohols on defoaming performance was examined and an acceptable dose of 1-octanol was determined. Results showed that defoaming ability, adhesion to fibers, and film behaviors depended on the alkyl group and dose of alcohols used. Straight alcohols were superior to the branched ones tested in defoaming ability and properties. Generally, 1-octanol was the best defoamer of the selected alcohols. Excessive increases in alkyl length and dose induced poor defoaming and damaged the adhesion and film behaviors.