Effect of Synthappret BAP on the Wrinkle Recovery of Uncrosslinked and Crosslinked Cotton

Abstract

The dry and wet wrinkle recovery angles of a cotton fabric are increased by treatment with the carbamoyl sulphonate-terminated poly(ether) urethane, Synthap pret BAP. This product cures best under alkaline conditions, but in the presence of an organometallic catalyst, it can also be cured under the acid conditions used to crosslink cotton with dimethyloldihydroxyethylene urea (DMDHEU). Synthappret BAP improves wrinkle recovery by decreasing the frictional component of wrinkling, probably through the formation of interfiber and interyam bonds. This contrasts with DMDHEU, which acts largely by changing the viscoelastic properties of the fibers. When the treatments are done separately, the improvements obtained with the elastomer and fiber crosslinker are additive for both dry and wet wrinkle recovery. Even better results are obtained however, when the treatment with Synthappret BAP, DMDHEU, and magnesium chloride catalyst is done from a single bath, provided a nonionic surfactant is present. The surfactant is necessary to prevent precipitation of the magnesium salt of Synthappret BAP. The practical significance of these results is that fabrics with dry and wet wrinkle recovery angles similar to those produced by treatment with a high level of DMDHEU alone can be produced by a pad-dry-cure method, using low concentra tions of Synthappret BAP (<1.0% solids omf) plus DMDHEU (1-2% solids omf). These fabrics have better abrasion resistance and tear and tensile strengths than fabrics treated solely with a high level of the crosslinker.