申请人:——
公开号:US20040162385A1
公开(公告)日:2004-08-19
Reactive polyurethanes containing free isocyanate groups but low levels of monomeric asymmetrical diisocyanate may be obtained by reacting a monomeric asymmetrical diisocyanate such as diphenylmethane-2,4′-diisocyanate (2,4′-MDI) containing less than 5% 4,4′-MDI and 2,2′-MDI, the 2,2′-MDI content being under 0.4%, with a polyhydric alcohol such as a diol with a molecular weight of 60 g/mol to 2,000 g/mol. The ratio of isocyanate groups to hydroxyl groups may be a value of 1.05:1 to 2.0:1. The reactive polyurethanes can be used to produce one- and two-component adhesive and sealant products.