Uv-curable Waterborne Polyurethane Acrylate Oligomers

Ultraviolet (UV) curable coating technology is gaining increasing interest as it allows high production speeds of coated articles. The UV curable waterborne coatings has both the advantages of UV curable coatings and waterborne coatings, such as environmental friendly, fast curable speed, energy saving, excellent performance of film, etc. It has been an important direction of coatings. The polyurethane-acrylate (PUA) coatings has been researched and applied more than others for its best performance.In this paper, a novel UV curable waterborne polyurethane acrylate (WPUA) for optimal properties with different functional capping agents, prepared from isophorone diisocyanate(IPDI), polypropylene glycol(PPG210)/polyester polyol (7112) and pentaerythritol tri-acrylate (PETA). Both the optimum conditions of the synthetic reactions and the effects such as the effects of hydrophilic group content on emulsions were studied for the PUA resins. The chemical modification was carried out by grafted epoxy resin (E-44) and the problem of stickiness of WPUA film before UV curable was solved effectively when we used the PPG/7112 as mixed soft segments. It was found that the film of WPUA after UV curable had a positive effect on the water resistance and solvent resistance, but base resistance thereof is on general level.In order to raise the resistance of the waterborne resin's films, a multifunctional capping UV curable WPUA with mixed hydrophilic groups and chemically modified polysiloxanes were prepared. The WPUA resin was prepared from IPDI, polysiloxane (WACKER IM 22 and IM 15), polyester polyol (7112) and PETA. Nonionic hydrophilic groups of polyethylene glycol (PEG600) were introduced into the WPUA chains could reduce the anionic hydrophilic group content of the DMPA; The results show that the problem of water resistance, solvent resistance, acid resistance and base resistance of WPUA film after UV curable was solved effectively when we used the mixed hydrophilic groups and the chemical modification was carried out by grafted E-44 and the polysiloxane...