Silicone-modified waterborne polyurethane for wash-free digital inkjet dyeing of polyester fabric with high surface colour and fastness

Disperse-dye wash-free digital inkjet dyeing, which combines digital jetting technology with disperse-dye wash-free dyeing technology, is a simple process that reduces carbon and pollutant emissions, conserves dyes and chemical materials and delivers a fast response. In this study, based on the principle of solubility parameter, a series of wash-free digital inkjet-dyeing waterborne polyurethane (WPU) which directionally delivered the disperse dyes, were prepared by employing isophorone diisocyanate (IPDI) as the hard monomer, polybutylene adipate (PBA) as the soft segment and polydimethylsiloxane (PDMS) as the modified soft segment. The results showed that the WPU film prepared from 6   wt% PDMS and 42   wt% IPDI, exhibited the highest water resistance, mechanical and adhesive properties, and directional dye delivery among the films. The optimal dosage of WPU in the wash-free ink was 6   wt%. Compared with the pure dye ink, the front colour yield of the inkjet-dyed fabrics with WPU wash-free ink reached 16.08 and improved by 18.1%. The colour fastness to dry/wet rubbing achieved grade 4-5 and grade 3-4, respectively. It demonstrated the good prospects of WPU in wash-free dyeing application. In particular, the approach promises inkjet-dyed polyester fabrics of high surface colour and fastness under no reduction-cleaning/washing procedures.