Wrinkling Behavior of Wool Fabrics: Part I: A Multiple-Pleat Test

A multiple-pleat test has been developed for measuring the change in wrinkling properties of light to medium-weight wool fabrics following various finishing and chemical treatments. Accordion pleats are inserted in a fabric sample (6 in. X 3 in.) by two meshing sets of 30° wedges under uniform load. After holding under the required conditions, the sample is removed and the average pleat angle is measured optically at three intervals over a period of one day. The complete wrinkling behavior is given by two terms, the percentage wrinkle recovery WR at a specified time (usually 15 min) and the recovery rate RR (WR change per unit log time). A sequence of short conditioning and pleating times at 85% RH and 30°C, with recovery at 65% RH and 21°C, is used to develop a large wrinkling effect. The method requires fewer samples than conventional 180°-fold methods and is more versatile under the specified testing conditions. Results show that the change in wrinkling properties during storage or after steam-pressing must not be overlooked in interpreting the results.