The Effect of Detergents on the Felting of Wool

Abstract

. Synthetic anionic and nononic detergents can produce higher felting rates than soap and the concentrations of detergents giving maximum felting rates can vary, with the type of machine used. In rotating-drum machines, maximum felting with synthetic detergents is found at about 0.01% concentration or less, compared with 0.05% in ma chines in which the wool is completely immersed for the duration of the test. With soap, maximum felting occurs at 0.05% in both types of machines.

The felting rates with commercial detergent formulations depend mostly on the con centration of active ingredient, although the relatively high pH (>10.0) of some "heavy-duty" detergent solutions may give lower felting rates than those with solutions of pH 6.8-9.6.

Tests for felting shrinkage carried out in the absence of detergents do not necessarily give a true indication of the degree of felting which is possible in machine washing, and standard tests may need to be related to the maximum, felting rates which could be encountered in practice.

The relative effects of different detergents are more marked with shrink-resistant than untreated wool and wool treated with some processes is more sensitive to the lubricating effect of detergents than that treated with other processes.