Radiation-curable mercaptoalkyl vinyl polydiorganosiloxanes, method of coating there with and coated article
AssigneeDow Corning Corporation
InventorsGary N. Bokerman, Joseph A. Colquhoun, David J. Gordon
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Abstract
Certain polydiorganosiloxane compositions bearing mercaptoalkyl radicals and vinyl radicals are disclosed which cure in the presence of radiation such as ultraviolet light. The compositions consist essentially of a mixture of a triorganosiloxane-endblocked polydiorganosiloxane fluid in which from 1 to 5 percent of the organic radicals are mercaptoalkyl radicals and a methylvinylpolysiloxane. The compositions may be applied to a substrate such as paper and exposed to radiation to prepare a coated substrate that provides premium release of aggressive acrylic adhesives.
Claims23
A radiation-curable polydiorganosiloxane composition consisting essentially of a mixture of
- A. a triorganosiloxane-endblocked polydiorganosiloxane fluid having a viscosity of at least 0.5 pascal-seconds at 25.degree. C., wherein from 50 to 99 percent of all organic radicals are methyl, from 1 to 5 percent of all organic radicals are mercaptoalkyl having the formula --(CH.sub.2).sub.n SH, wherein n has a value of from 1 to 4 inclusive, any remaining organic radicals in (A) being alkyl radicals having from 2 to 6, inclusive, carbon atoms or phenyl, and
- B. a methylvinylpolysiloxane, compatible with (A) and having an average of at least three vinyl groups per molecule, the amount of (B) being sufficient to provide from 0.2 to 1.0 silicon-bonded vinyl radicals for every silicon-bonded mercaptoalkyl radical in the composition.
A method of treating a solid substrate to improve the release of adhesive materials therefrom, said method comprising
- I. applying to the solid substrate a composition obtained by mixing components consisting essentially of
- A. a triorganosiloxane-endblocked polydiorganosiloxane fluid having a viscosity of at least 0.5 pascal-seconds at 25.degree. C., wherein from 50 to 99 percent of all organic radicals are methyl, from 1 to 5 percent of all organic radicals are mercaptoalkyl having the formula --(CH.sub.2).sub.n SH, wherein n has a value of from 1 to 4 inclusive, any remaining organic radicals in (A) being alkyl radicals having from 2 to 6, inclusive, carbon atoms and phenyl, and
- B. a methylvinylpolysiloxane, compatible with (A) and having an average of at least three vinyl groups per molecule, the amount of (B) being sufficient to provide from 0.2 to 1.0 silicon-bonded vinyl radicals for every silicon-bonded mercaptoalkyl radical in the composition,
- Ii. exposing the applied composition to energetic radiation, and
- Iii. recovering an article comprising the solid substrate having adhered thereto a cured polydiorganosiloxane that will provide premium release of aggressive acrylic adhesives therefrom.
Dependencies are inferred from the claim text.