| 摘要 |
The present invention relates to a process for producing a non-woven fabric comprising impregnating a non-woven fibrous web with an aqueous binding agent dispersion containing, as coagulation agent, a polyurethane having a weight average molecular weight of from 500 to 20,000 which is the reaction product of (i) a polyoxyalkylated aliphatic amine containing d nitrogen atoms, where d is 1 to 5, and where d is greater than 1, each nitrogen atom is connected with the next by a (C2-4) alkylene moiety and from d+1 to d+2 polyoxy(C2-4)alkylene units, with the proviso that the molecule contains C2 alkyleneoxy units and C3 and/or C4 alkyleneoxy units with the C3 and/or C4 units forming the majority of alkyleneoxy units, and (ii) from 0.1 mols to 2 mols per mol of (i) but not exceeding the stoichiometric amount of a polyisocyanate, which product is optionally in quaternized form and, is present in an amount of from 0.5 to 50 parts per weight per 100 parts of binder solids, followed by drying the web.
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