Synthesis and Application of a Polymeric Crosslinking Agent for Improving Fixation of Vinylsulfone-type Dyes on Cotton by a Pad-drycure Process

A new class of novel polymeric crosslinging agent （NPCA）, which contained silane coupling group and the epoxy groups, was designed and synthesized in our laboratory. NPCA was a non-formaldehyde multifunctional crosslinking polymer. The cotton fabrics dyed with 8.0% （owf） Vinylsulpone-type dyes were treated with 3.0%- 4.0% NPCA, 0.5 mol/L potassium thiocyanate as a catalyst, then padded through two dips and two nips to reach a wet pickup of 80%- 85%, then dried at 80℃ for 2 minutes and cured in oven at 140- 150℃ for 3 minutes. Crocking fastness and fixation （%） were improved with up to 1.0 -1. 5 units, 35%- 50%, respectively. And there was little difference between the color yield of dyed fabrics before and after the treatment at certain conditions. The possible crosslinking mechanism of NPCA was also investigated. It was concluded that NPCA can improve colorfastness of cotton fabric by means of the three-dimensional network, covalent bonding and other molecular forces.