Preparation of WPU Wet-Rubbing Fastness Improver

A wet-rubbing fastness improver was prepared by two steps: (1) synthesis of waterborne polyurethane (WPU) through the reaction of diphenylmethane diisocyanate (MDI), polyethylene glycol (PEG), dimethylol propionic acid (DMPA), and diethylenetriamine; (2) modification of WPU by reaction with epichlorohydrin. Influence of temperature, time, concentration and ratio of monomers on the preparation was studied. The optimal process for WPU synthesis is as follows: temperature 100°C, time 3h, diethylenetriamine 1.5 % and DMPA7% (on weight of monomers). The modification reaction can be proceeded at temperature 100°C for 2h with epichlorohydrin 2.7 %.