Radiation activated addition reaction
AssigneeMinnesota Mining and Manufacturing Company
InventorTimothy J. Drahnak
Life of this patent
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Abstract
A process for the addition of compounds containing silicon-bonded hydrogen to compounds containing aliphatic unsaturation. The process is activated by actinic radiation and is conducted in the presence of a platinum complex having an ultraviolet displaceable group.
Claims18
In a hydrosilation process which comprises reacting a composition comprising a compound having aliphatic unsaturation and a compound containing at least one silicon-bonded hydrogen atom and not having more than two hydrogen atoms attached to any one silicon atom, in the presence of a platinum catalyst, the improvement which comprises using as the platinum catalyst, a (.eta.-diolefin)(.sigma.-aryl) platinum complex having an ultraviolet displaceable group.
A composition which comprises
- (a) a silicon compound containing at least one hydrogen atom attached to silicon per molecule, there being not more than two hydrogen atoms attached to any one silicon atom,
- (b) a compound containing aliphatic unsaturation, and
- (c) a (.eta.-diolefin)(.sigma.-aryl)platinum complex having an ultraviolet displaceable group.
Radiation curable composition comprising
- (a) polyorganohydrosiloxane having the general formula:
- ##STR16## wherein each R.sup.10 is independently an alkyl radical, a cycloalkyl radical, a phenyl radical, a hydroxyalkyl radical, a (polyalkoxy)alkyl radical or hydrogen, at least two but no more than 50% of all R.sup.10 groups being hydrogen;
- m is 0, 1, 2 or 3, and
- n is a number having an average value from one to 275 such that when considered with the value of m provides a molecular weight to the polyorganohydrosiloxane of between 134 and 20,000, (b) a polyorganosiloxane having the general formula:
- ##STR17## wherein each R.sup.8 is independently an unhalogenated or halogenated ethylenically unsaturated radical;
- an unhalogenated or halogenated alkyl radical or cycloalkyl radical, or the phenyl radical, at least 90% of all R.sup.8 radicals being methyl radicals, but no more than 10% of all R.sup.8 radicals being vinyl or propenyl, and at least two of the R.sup.8 radicals being vinyl or propenyl,
- h is a number having a value from about 75 to 250 such that the polyorganovinylsiloxane has a viscosity from about 0.3 to 3 pascal-seconds (300 to 3000 centipoise) at 25.degree. C., and
- g is 0,1,2, or 3,
- (c) a platinum complex represented by the formula:
- ##STR18## wherein R.sup.1 is an alkadiene that is .pi.-bonded to platinum, the alkadiene being a straight or branched chain or a cyclic ring, the alkadiene further being unsubstituted or substituted by one or more groups that are inert in a hydrosilation reaction;
- R.sup.2 and R.sup.3 are aryl radicals that are .sigma.-bonded to platinum and are independently selected from monocyclic and polycyclic aryl radicals, said aryl radicals being unsubstituted or substituted by one or more radicals that are inert in a hydrosilation reaction;
- R.sup.4 and R.sup.5 are independently hydrogen or an ortho-alkenyl radical, said alkenyl radical being in a straight or branched chain or in a ring, the unsaturated bond of the alkenyl radical being in the 2- or 3-position with respect to the .sigma.-bonded position;
- a is zero or one, being zero only when both R.sup.4 and R.sup.5 are ortho-alkenyl radicals, and one when either R.sup.4 or R.sup.5 is not an ortho-alkenyl radical.
Dependencies are inferred from the claim text.