| abstract |
Silicone urethane compounds, e.g., a polysiloxane urethane (meth)acrylate, obtained as a reaction product of a polysiloxane carbinol, a polyisocyanate, and a polyfunctional compound having at least one functional group which is reactive with an isocyanate group of the polyisocyanate and after reaction therewith provides an ethylenic functional group in the reaction product. The polysiloxane carbinol has a molecular weight of from about 5,000 to about 50,000 and has R'OH end groups wherein R' is linear C4-C20 alkylene. Such carbinol may be obtained as a reaction product of the corresponding hydride-terminated polysiloxane and a linear C4-C20 omega -alkenyl alcohol. The hydride-terminated polysiloxane in turn may be obtained as a reaction product of either (i) the corresponding silanol of molecular weight at least 10,000 and a hydridosilane having one or more hydrolyzable groups attached to the silicon atom, or (ii) a cyclosiloxane and a 1,3-dihydrido disiloxane. The disclosed compounds may be utilized in adhesive compositions for substrates including bonding surfaces such as glass, and polymers and copolymers of ethylenically unsaturated monomers. The bonding of such substrates may suitably be carried out at least partially under anoxic conditions, e.g., with elevated temperature and/or actinic radiation curing of the bonding composition in a substantially oxygen-free environment. A preferred vacuum degassing/anoxic curing process is disclosed for such bonding compositions, which is particularly advantageous for difficult to bond substrates, such as low density polyethylene. |