Synthesis of Benzotriazole UV Absorbers with Blocked Hydroxy Group and Their Application to UV Curable Paint

Keiji HIDA* and Hideo TOMIOKA

Aichi Factory Resin Product Division, Nippon Paint Co., Ltd.; 3-1-5, Shinden-cho, Takahama-shi 444-1301 Japan
Faculty of Engineering Chemistry, Department for Materials, Mie University; 1515, Kamihama-cho, Tsu-shi 514-0008 Japan

In order to realize ideal UV absorbers which do not disturb UV curing processes and yet can act as a absorber, the hydroxy group of 2-(2H-benzotriazol-2-yl)phenol was blocked with a diphenylphosphinyl group and the properties of the resulting blocked benzotriazole derivative were examined.
The results indicated that the triazole showed almost no negative effect on the UV curing processes, but improved the weatherbility of the cured paints.
Spectroscopic studies were carried out in order to reveal the origin of the present observations, which suggested that strong emission from the benzotriazole played an important role.

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