Rate of Felting of Untreated and Shrink-Resistant Wool Fabrics

Abstract

Shrinkage-time curves for a range of wool fabrics, and the effect of various shrink- proofing treatments on these curves, have been studied. Felting rates of untreated fabrics depend on fabric structure and applied force in the way previously established [e.g., 3, 13, 15]. The shrinkage-time curves of treated fabrics show two definite stages, an initial portion indicating a very low felting rate, followed by a second stage where felting may be much more rapid. For a given fabric structure and given applied force, the felting rates of both stages, and the times at which the second stage begins, depend on the degree of treatment. The two-stage curves indicate two distinct steps in the felting of the fabrics and are not due to the fibers being unevenly treated. Frictional properties of treated Merino 64's fibers show no correlation with shrink resistance, and the results are qualitatively different from those found with Lincoln 36's. The importance of defining washing conditions when testing shrink-resistant wool fabrics is again emphasized by results showing that quite different impressions can be gained by washing in different machines and thereby applying different mechanical forces to the fabrics. In an extreme case, a treated fabric of loose structure, when washed for a given time in two different machines, can appear to be either completely shrinkproofed or scarcely shrink-resistant at all.