Synthesis And Modification Of IPDI-Based Waterborne Polyurethane

IPDI-based waterborne polyurethane was synthesized and modified to get low modulus and high strength PU film for application in gloves and so on.First, the preparation of linear waterborne polyurethane emulsion was studied using polyethylene glycol (PPG) as soft segment and isophorone diisocyanate (IPDI) as hardsegment. It was found that the higher the DMPA content, the film was much easier to absorb water and DMPA of 7% was better. When nNco/noHis about 3.0, film with a lower modulus, higher strength and a suitable elongation at break could be obtained. By adjustment and optimization, basic formula was obtained for preparation of PU film.To improve the mechanical properties of PU film, especially the tensile strength, cross-linked polyurethane film was prepared by adding some types of external crosslinking agent. It was found that cross-linking agent containing carboxyl group could make the emulsion instability, while the cross-linking agent containing hydroxyl group have little effect on stability.To improve the cross-linking efficiency, terminal hydroxyl group content was increased. DEA contains a secondary amine group, had good result than TMP which contains three hydroxyl groups. When DEA was added after the chain extender reacted completely, the water-based PU had a good stability. The higher the DEA content, the better the water resistance and the lower the molecular weight. When the DEA content of 0.5%, and adding BI7963 with 2.8%, the elongation at break, tensile strength and modulus of PU film was up to 995%,14.9MPa and 2.1MPa at 100% elongation modulus, respectively. The stretch recoverability was also good.