Cross-linked polyurethane elastomers and microcellular foams
AssigneeStamicarbon B.V.
InventorsKurt C. Frisch, Daniel M. J. Tummers, Anne Te Nijenhuis
Life of this patent
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Abstract
Cross-linked polyurethanes such as solid elastomeric polyurethanes or microcellular polyurethanes are prepared by reacting a polyisocyanate, one or more polyols and at least one trihydroxy compound in the presence of a catalyst using, as the hydroxyl compounds a low molecular weight diol, optionally a polymeric polyol and tris-(.beta.-hydroxypropyl)-isocyanaurate or ethoxylated tris-(.beta.-hydroxypropyl)-isocyanurate all present in specific ranges of proportions. Use of the specific isocyanurates provides for better utilization and smaller quantities of the blowing agent used to make microcellular polyurethane foams.
Claims19
In a process for preparing a cross-linked polyurethane elastomer by reacting a polyisocyanate, at least one polyol, and at least one trihydroxy compound, optionally in the presence of a catalyst, the improvement wherein the hydroxyl compounds employed are:
- A-1. a polymeric polyol compound having a molecular weight of between about 500 and about 10,000 and an average of 2 to 3 hydroxy groups per molecule;
- A-2. a dihydroxy compound having a molecular weight of between about 60 and about 200, in a quantity such that the ratio between the hydroxyl groups derived from the low molecular weight diol (A-2) and the hydroxyl groups derived from the polymeric polyol (A-1) is between about 0:1 and about 5:1;
- and
- B. tris-(.beta.-hydroxypropyl)-isocyanurate or ethoxylated tris(.beta.-hydroxypropyl)-isocyanurate such that the ratio between the hydroxyl groups derived from the isocyanurate and the hydroxyl groups derived from the sum of the polyols (A-1) and (A-2) is between about 0.5:1 and about 5:1.
In a process for preparing a microcellular polyurethane foam by reacting a polyisocyanate, at least one polyol, and at least one trihydroxy compound, optionally in the presence of a catalyst, the improvement wherein the hydroxyl compounds employed are:
- A-1. a polymeric polyol compound having a molecular weight of between about 500 and about 10,000 and an average of 2 to 3 hydroxy groups per molecule;
- A-2. a dihydroxy compound having a molecular weight of between 60 and about 200, and present in an amount such that the ratio between the hydroxyl groups derived from the diol (A-2) and the hydroxyl groups derived from the polymeric polyol (A-1) is between about 0.5:1 and about 3:1;
- and
- B. tris-(.beta.-hydroxypropyl)-isocyanurate or ethoxylated tris(.beta.-hydroxypropyl)-isocyanurate such that the ratio between the hydroxyl groups derived from the isocyanurate and the hydroxyl groups derived from the sum of the polyols (A-1 and A-2) is between about 0.5:1 and about 5:1.
Dependencies are inferred from the claim text.