Stable, moisture-curable silicone pressure sensitive adhesives
AssigneeDow Corning Corporation
InventorsJoseph N. Clark, Robert H. Krahnke, Shawn K. Mealey, William J. Schoenherr
Life of this patent
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Abstract
Silicone pressure sensitive adhesive compositions which cure in the presence of moisture comprise an adhesive component which bears alkoxy radical-containing curing radicals, a catalyst to accelerate the reaction of moisture with the alkoxy radicals to form siloxane bonds and a multialkoxy silicon compound to stabilize the composition in the solventless state. Curing provides adhesives ranging from pressure sensitive adhesives having improved properties to permanent adhesives. The adhesives are useful for adhering an object to a surface and thereafter improving the bond between the object and the surface by exposure to moisture.
Claims10
A composition comprising:
- (A) a silanol-free silicone pressure sensitive adhesive component bearing curing radicals having the formula (MeO).sub.3 SiC.sub.2 H.sub.4 SiMe.sub.2 O-- and capping radicals having the formula Me.sub.3 SiO-- wherein Me denotes methyl;
- (B) an effective amount of a catalyst component to accelerate the reaction of the curing radicals with moisture to form siloxane bonds;
- and
- (C) an effective amount of a silane compound, or partial hydrolyzates and/or condensates thereof, bearing a plurality of silicon-bonded alkoxy radicals to improve the shelf life of the composition;
- wherein the silanol-free silicone pressure sensitive adhesive component (A) bearing curing radicals has been prepared by a method comprising reacting (i) a silicone pressure sensitive adhesive composition having reactive sites of the formula .tbd.SiX, and X denotes an alkenyl radical, a hydroxyl radical or a hydrogen atom, substantially all X being OH, with (ii) a moisture-reactive compound having the formula {(MeO).sub.3 SiC.sub.2 H.sub.4 SiMe.sub.2 }.sub.2 Nh, and with (iii) a silanol-capping compound having the formula (Me.sub.3 Si)NH;
- all other silicon-bonded radicals in (i) being selected from the group consisting of divalent oxygen atoms linking silicon atoms, hydrogen atoms and monovalent hydrocarbon radicals.
Dependencies are inferred from the claim text.