Synthesis And Properties Of Water Retardant Silicone Modified Polyurethane Fabric Finishing Agent

When the polymer was used as a water-repellent finishing agent, the fabric not only had high water-repellent that fabric not soaked in heavy rain, but also required breathable, thin, soft, comfortable, washable and good durability. The finishing process should be simple and environmental. After the treatment, there was no toxic residue and the fabric is of good physical health. The raw materials should be easy to get and the price is as cheap as possible. After treatment of the water dispersible polymer finishing agent, the fabric was still poor water-repellent, washable and adhesion ability. In this dissertation, because of low toxicity, the moderate boiling point and easy recovery, isopropanol was used as the solvent to synthesis solvent-based siloxane-polyurethane fabric finishing agent.Amino-terminated polydimethylsiloane (SN2) was synthesized by using hydroxyl-terminated PDMS and aminopropyl siloxane coupling agent (DB-912). And the siloxane-polyurethane (Si-PU) block copolymer was synthesized using SN2as a chain extender. Effects of the feed ratio of SN2and prepolymer of polyurethane on the rheological behavior of the copolymer solution in isopropanol and the properties of its film were studied. It was found that the Si-PU block copolymer solution (25wt%) exhibited low apparent viscosity. The surface contact angles of the films were higher than110°. The water absorption was low and the water-repellent were good. With the increasing of SN2block ratio, the surface contact angles of films to water increased slightly. When the content of siloxane block was up to40wt%, the contact angles increased obviously. Moreover, the water absorption of copolymer films were low (less than1.5wt%). With the content of siloxane block increased, the water absorption of films declined a little. But when the siloxane content was higher than46wt%, the water absorption increased instead. And siloxane improved the heat resistant of polyurethane. The innovation of this work is to use the end of aminopropyl polysiloxane oligomer as chain extender. Isopropanol was used as solvent and the water-repel lency of the copolymer was improved, the aggregation process was simplified and the cost was reduced.