| 摘要 |
<p>The present invention relates to a process for the preparation of polyurethane resins, in which, in an ester as solvent, a) at least one compound having 2 hydroxyl and/or amino groups, b) at least one di- and/or polyisocyanate, c) at least one compound containing 2 groups which are reactive toward isocyanate groups, these compounds containing, at least in part, at least one group capable of forming anions which is neutralized before or after incorporation of component (c) into the polyurethane molecule, and d) at least one compound having at least 3 hydroxyl and/or amino groups are used to prepare a polyurethane resin, preferably using components (a), (b) and (c) to prepare an intermediate which has terminal isocyanate groups and at least some of whose free isocyanate groups are subsequently reacted with component (d), characterized in that ethoxyethyl propionate is employed as solvent.</p> |
