| 摘要 |
A flexible, hydrophobic polyurethane foam is produced by mixing together an aqueous phase which can optionally contain reinforcing fibers and surfactants and a resin phase comprising a prepolymer derived from a poly (oxy C2-4 alkylene) diol having a molecular weight of at least about 1100, an MDI containing isocyanate product having a functionality greater than 2.0 made of a mixture of MDI and isocyanate containing derivatives of MDI, and a monomeric polyol crosslinking agent having 3 or 4 hydroxyl equivalents per mole. The preferred polyol is trimethylolpropane and the diol is an equimolar mixture of Carbowax 1000 and Carbowax 1450. The diol and the polyol, such as trimethylolpropane, are present in a mole ratio in the range of 4:1 to 8:1 while the ratio of the isocyanate equivalents to the total hydroxyl equivalents is in the range of 2.5:1 to 3.5:1. The isocyanate containing product comprises less than 50% by weight of the prepolymer and Isonate 143L is the preferred isocyanate product. Flexible foams are obtained which are water-absorbing for medical or personal care applications. |
