Back to results
US 4,766,176 AGranted
Storage stable heat curable organosiloxane compositions containing microencapsulated platinum-containing catalysts
AssigneeDow Corning Corporation
InventorsChi-long Lee, Donnie R. Juen, John C. Saam, Robin L. Willis, Jr.
Life of this patent
Estimating the term…
Abstract
Storage stable, one part organosiloxane compositions that cure upon heating by a platinum-catalyzed hydrosilation reaction comprise, in addition to the organosiloxane reactants, a platinum-containing hydrosilation catalyst that is microencapsulated within one or two layers of thermoplastic organic polymers. The microcapsules are formed using known techniques.
Claims13
In an improved one-part, storage stable, heat curable organosiloxane composition comprising
- (A) a curable polyorganosiloxane containing at least two ethylenically unsaturated hydrocarbon radicals per molecule;
- (B) an organohydrogensiloxane containing at least two silicon bonded hydrogen atoms per molecule in an amount sufficient to achieve curing of said polyorganosiloxane (A), where the sum of the average number of ethylenically unsaturated hydrocarbon radicals per molecule of (A) and the average number of silicon bonded hydrogen atoms per molecule of said organohydrogensiloxane (B) is greater than 4, and
- (C) an amount of a platinum-containing hydrosilation catalyst sufficient to promote curing of said composition at a temperature of at least 70.degree. C. and above,
- the improvement comprising the presence of said platinum-containing catalyst in the form of microcapsules that in turn, comprise said catalyst as finely divided particles or droplets that are completely enveloped within a thermoplastic organic polymer where the average diameter of said microcapsules is less than 500 microns, and said thermoplastic organic polymer constitutes at least 50 percent of the weight of said microcapsules.
1 more element
Dependencies are inferred from the claim text.