Effects of Suessen Heat Setting Variables on Streaks in Finished Nylon Carpet

Abstract

The effects of dry heat setting conditions on streaks in finished carpets made from nylon 66 staple yams are considered. Two different polymers were subjected to con trolled variation in heat-set temperature, residence time, and chamber steam pressure on a Suessen machine according to a factorial design. Yarns from some of the items were made into finished carpets, and other items were implanted into these carpets using two adjacent creel positions. Streak intensity grades were assigned to these im plants, and then an empirical model was fit to the data relating streak intensity to the differences between the background and implant items in heat setting conditions. Streaks caused by variation in heat setting conditions are associated with differences in dye uptake rather than with physical or textural differences between tuftlines. If the Suessen is operated at a nominal temperature of 200°C, then surprisingly large dif ferences in heat setting conditions are required in order to cause an objectionable streak. Furthermore, the effect of heat-set temperature differences on carpet streaks depends on the dyeing system used. For a continuous dyeing system, which has a dye uptake minimum at 200°C, any tuftline-to-tuftline heat-set temperature variation from 200°C causes dark streaks. On the other hand, the Beck system has a linear rather than a U-shaped dye response to heat-set temperature, and increases considerably above 200°C cause light streaks when that tuftline is implanted within a group of tuftlines having experienced a 200°C temperature.