摘要 |
<p>Silane-functionalized ultraviolet screening agent precursors comprise compounds of the formula: <IMAGE> <IMAGE> +TR <IMAGE> wherein R is <IMAGE> R1 is C1-C6 alkyl, R2 is C1-C6 alkyl or C2-C6 alkanoyl, R3 is hydrogen or C1-C6 alkoxyl, X is 0,1 or 2, y is 1,2, or 3 and x+y=3. Under ultraviolet radiation the compounds rearrange to the corresponding alpha -hydroxybenzophenones which protect substrates, especially transparent plastics, against degradation.</p> |