The photostability of shrinkproofing polymer systems on wool fabric

Abstract

The UV absorbers Cibafast W and Uvinul DS49 were applied to wool treated with various shrinkproofing polymer systems. The photoprotective effects conferred by these absorbers in the presence of a surface polymer application on wool were assessed with respect to breaking strength, yellowness and retention of the shrink resist effect. Exposure tests were carried out using MBTF and natural sunlight irradiation. Following prolonged exposure the efficacy of the Cibafast W absorber, with respect to improving wool fabric breaking strength, was diminished on application to Synthappret BAP and Basolan SW treated wools, but not in the cases of the Hercosett 57 and Ultratex EMJ treated wools. Effective retention of wool fabric breaking strength was observed for the Hercosett-Uvinul DS49 system with combined application of the antioxidant, I1425. The shrink resistances of Hercosett 57 and Ultratex EMJ treated wools are fully retained, while those of Basolan SW and Synthappret BAP are completely lost. None of the polymer-absorber-antioxidant systems investigated in this work retard the photoyellowing of wool during natural sunlight exposure.