Solution-stable, moisture-curable silicone pressure sensitive adhesives
AssigneeDow Corning Corporation
InventorsRobert H. Krahnke, Shawn K. Mealey, William J. Schoenherr
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Abstract
Silicone pressure sensitive adhesive compositions which are stable in the absence of moisture but which cure in the presence of moisture comprise an adhesive component which bears alkoxy radical-containing curing radicals and, optionally, a catalyst to accelerate the reaction of moisture with the alkoxy radicals to form siloxane bonds. 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 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 R.sub.b (OR').sub.3-b SiY wherein Y denotes a radical which is reactive with .tbd.SiX, whereby the Y-substituted silicon atom is linked with the X-substituted silicon atom by a divalet Z radical, R denotes a monovalent hydrocarbon radical, R' denotes an alkyl or alkoxyalkyl radical, and the subscript b has a value of 0 or 1;
- and with (iii) a silanol-capping compound having the formula R.sub.3 SiY' wherein Y' denotes a radical which is reactive with silanol, whereby the Y'-substituted silicon atom is linked with the silanol-substituted silicon atom by a divalent oxygen atom, and R denotes a monovalent hydrocarbon radical;
- 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;
- the moisture-reactive compound and the silanol-capping compound comprise disilazanes and said reacting is promoted by the action of an acid catalyst.
Dependencies are inferred from the claim text.