| abstract |
The present invention relates to latent tri-component polyurethane adhesive compositions comprising: (a) a first polyol component comprising (i) at least one polyol having a hydroxyl equivalent weight of 400 to 2,000 and a nominal hydroxyl functionality of 2 to 4 ; (ii) at least one aliphatic diol chain extender; (iii) from 0.01 to 1% by weight, based on the total weight of the first polyol component, of at least one latent organometallic catalyst at room temperature; and (iv) from 0.01 to 1% by weight, based on the total weight of the first polyol component, of at least one blocked cyclic amidine compound catalyst or at least one blocked cyclic amidine catalyst. phenolic; (b) a second polyol component comprising (i) at least one polyol having a hydroxyl equivalent weight of 400 to 2,000 and a nominal hydroxyl functionality of 2 to 4; (ii) at least one aliphatic diol chain extender; (iii) from 0.01 to 1% by weight, based on the total weight of the second polyol component, of at least one latent organometallic catalyst at room temperature; and (iv) from 0.01 to 1% by weight, based on the total weight of the second polyol component, of at least one blocked cyclic amidine compound catalyst or at least one blocked cyclic amidine catalyst. phenolic; and (c) an isocyanate component comprising (i) at least one isocyanate compound; the isocyanate component and the first and second polyol components being contacted at an isocyanate index of between 0.5 and 2. |