Textile Warp Size Reclamation Using Thermal Precipitation

摘要

The report describes a novel method for reclaiming size based on precipitation of the size material by heating the desize washwater. The method uses hydroxypropyl cellulose (HPC) or hydroxypropyl methylcellulose (HPMC) which are soluble in cool water but insoluble in warm water. Reclaiming size would eliminate most of the BOD typically resulting from sizing and desizing. Since maximum system temperature with HPC is about 50C, compared to 95C for a conventional system, considerable energy is conserved. Strength and elongation of yarns sized with virgin HPC and with reclaimed HPC were not significantly different from those of yarns sized with the conventional size, polyvinyl alcohol (PVA), at similar add-on levels. Abrasion resistence of yarns sized with HPC was lower than that of yarns sized with PVA at similar add-on levels. Weaving of HPC-sized 50/50 polyester/cotton yarns in the laboratory was successful. In production weaving of percale sheeting, HPC accumulated on the shuttle caused poor weaving efficiency. The capital investment for reclaiming HPC using thermal precipitation is much lower than for reclaiming PVA using ultrafiltration. Operating costs for recovering HPC by thermal precipitation and for recovering PVA by ultrafiltration represent a savings over conventional sizing and desizing without reclaiming size.