Siloxane polyphotoinitiators of the substituted acetophenone type

Abstract

An organopolysiloxane photoinitiator having an average of at least two siloxane units, of which at least an average of one siloxane unit per organopolysiloxane molecule has the formula: X.sub.a R.sub.b SiO.sub.(4-a-b)/2 wherein a is an integer of 1-3, b is a integer of 0-2 and a plus b equals 1-3; R is C.sub.1 -C.sub.10 hydrocarbyl or halogen substituted C.sub.1 -C.sub.10 hydrocarbyl; and X is substituted acetophenone photomoiety of the formula: ##STR1## where R.sup.1 is any substitutent which will not interfere with hydrosilation, n is an integer between 0 and 4; R.sup.2 is organosilyl substituted alkyl or alkenyl; R.sup.3 is H, alkyl or aryl; and R.sup.4 is a divalent hydrocarbon group having between 2 and 10 carbon atoms. The silicones are prepared by hydrosilation of the corresponding olefinically or acetylenically .alpha.,.alpha.-dialkenylacetophenones or .alpha.,.alpha.-dialkynylacetophenones.

Dependencies are inferred from the claim text.