Synthesis of waterborne polyurethane and its application on cotton fabric

Two-component waterborne polyurethane coating agent consists of a polyisocyanate as a curing agent and a dispersion polyol of aqueous crosslinked polyurethane,which was synthesized by using polycarbonate diol(PCDL),dimethylol propionic acid(DMPA) and isophorone diisocyanate(IPDI) as prepolymerization material and then extended with trimethylol propane(TMP).It was applied on cotton fabric surface in order to research the effect of polyurethane coating on the water resistance of cotton fabric,and the treated cotton fabrics were characterized with scanning electron microscopy(SEM),contact angle and water absorption analysis.The results indicate that the fiber bundles on the surface of the treated cotton fabric are tightly conglutinated together by the coating,showing very good hydrophobicity;the contact angle for water can reach 130°;and the water absorption rate is decreased to 9%.In addition,it also shows good washing durability,the contact angle still reach 90° even after 12 washing cycles and the water absorption rate is much smaller as compared with the fabric before treatment.