Synthesis and characterization of PDMS modified UV-curable waterborne polyurethane dispersions for soft tact layers

A series of UV-curable waterborne polyurethane dispersions (Si-PUs) modified by hydroxybutyl-terminated polydimethylsiloxanes (PDMS) were synthesized by incorporating the PDMS into the soft segment of PU chains. The structure was confirmed by the Fourier transform infrared spectroscopy (FTIR). The effect of PDMS content on the Si-PUs properties was investigated. The results of UV curing behaviors showed that the incorporation of PDMS decreased the C = C conversion rate but had little effect on the final conversion. Water resistance and surface properties of the UV cured films with different PDMS content had been investigated. The water diffusion behavior in the films agreed with the Fickian diffusion mechanism. The investigation of the scrub resistance to methyl ethyl ketone (MEK) and the flexibility illustrated that PDMS modified UV-curable waterborne polyurethanes could exhibit both good chemical resistance and flexibility. In addition, the tensile strength of the films with different PDMS content was also studied. (c) 2007 Elsevier B.V. All rights reserved.