Abstract: A UV varnish suitable for coating on thermoplastic silver powder primers was prepared by using polyurethane acrylic acid with six functions and two functions as prepolymers, dipentaerythritol hexaacrylate (DPHA) and tricyclodecane dimethanol diacrylate (DCPDA) as photosensitive monomers, and 1-hydroxycyclohexyl phenyl ketone (184) as photoinitiator, and the effects of the ratio of DPHA to DCPDA on the hardness, adhesion, water resistance, gloss, high and low temperature impact properties of UV varnish were had studied. The results showed that the ratio of DPHA/DCPDA had a great influence on UV varnish performance. With the increase of DPHA/DCPDA ratio, the hardness of UV varnish increased from HB to 2H, the adhesion decreased from grade 0 to grade 2, and the gloss decreased from 109 GU to 93 GU. When DPHA /DCPDA ratio was 1∶3, the adhesion, water resistance and high and low temperature impact performance of UV varnish reached the best.

Key words: Photoactive monomer, UV varnish, Volume shrinkage, Monomer proportion