Siloxane modified cycloaliphatic epoxide UV coatings

Tetraethyl orthosilicate (TEOS) functionalized caprolactone diol and triol were used to modify cycloaliphatic diepoxide/caprolactone polyol cationic u ltraviolet (UV) curable coatings. Two levels of the cycloaliphatic diepoxid e (60 and 70 wt.%) were used in the coating formulations. Siloxane function alized polyols were added to the cycloaliphatic diepoxide/caprolactone poly ol coating formulations as a replacement of the parent caprolactone polyols . To monitor the potlife, the viscosity of the coating formulations was mea sured as a function of storage time. The coatings were evaluated in terms o f Tukon hardness, tensile properties, wet pull-off adhesion, glass transiti on temperature, gloss, and dark cure. The addition of the siloxane function alized polyols into the coating formulations significantly increased the gl ass transition temperature and Tukon hardness. Wet adhesion and gloss were also improved. The addition of the siloxane functionalized polyols, however reduced the potlife of the coatings. (C) 1999 Elsevier Science S.A. All ri ghts reserved.