| 摘要 |
Cationic polyurethanes are prepared by reacting a monomeric, aliphatic dihydroxyl compound containing a maximum of 7 atoms between the two hydroxyl groups and containing an aliphatic radical having at least 10 carbon atoms on one of said atoms with a polyisocyanate to give a preadduct containing NCO end groups, chain-extending the resultant preadduct by means of an aliphatic monomeric diol containing tertiary nitrogen, and converting the chain-extended product into an ammonium compound. These polyurethanes are particularly suitable as the active component in paper sizes. The sizes can be employed both in bulk sizing and in the surface sizing of paper and give sized papers having a high degree of sizing and a low Cobb value. Sizing in a relatively broad pH range is possible, and the polyurethanes can be processed very well together with products usually used for sizing. |
