| 摘要 |
An aqueous dispersion containing a high molecular polyurethane A and additive B where A has a number average mol. wt. of at least 10 kg/mole and a weight average mol. wt. of at least 20 kg/mole, and B contains mercaptan, hydrazide and/or N-alkylamide groups is new. An Independent claim is included for a process for preparation of the aqueous dispersion where in a first step an isocyanate functional prepolymer is prepared by reaction of a polyisocyanate AA with polyol AB of number average mol. wt. Mn of at least 400, preferably a low molecular polyolefin AC, and compounds AD which have at least two groups reactive to isocyanates and at least one group capable of forming anions to give a free NCO containing prepolymer of Staudinger index Jo of at least 20, preferably 26 cm3/g, and in a second step reaction of the neutralized prepolymer with at least one component selected from low molecular polyols AE, which have no further groups reactive to isocyanate, where these compounds are in excess, compounds AF, which are monofunctional with respect to isocyanates or contain active hydrogen atoms of different reactivities and are different from compounds AE, and compounds AG, which are different from compounds AB, AC, AD, AE, and AF and contain at least two groups reactive to NCO groups.
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