Verfahren zur Umwandlung von wasser-unloeslichen hochmolekularen Polymeren aus alpha, beta-aethylenisch ungesaettigten Aldehyden in wasserloesliche Derivate

摘要

A process for converting a water-insoluble high molecular weight polymer of an alpha-beta-ethylenically unsaturated aldehyde into a water-soluble derivative, comprises dissolving the water-insoluble polymer in an aqueous medium which contains as a dissolving agent a material which releases sulphur dioxide if heated to 100 DEG C., while maintaining the aqueous medium in the pH range of from 5.5 to 7.5. Dissolving agents used are sodium bisulphite, sodium metabisulphite and sulphur dioxide solution.ALSO:An aqueous solution of a water-soluble dervative of a polymer of air a -b -ethylenically unsaturated aldehyde prepared by dissolving the water unsoluble polymer in an aqueous medium containing a material which releases sulphur dioxide when heated to 100 DEG C. at a pH of 5.5 to 7.5 (see Division C3) is useful as a wet strength agent for paper. The solution may be added during the beater stage or as an after treatment for the paper. The addition may be at the beginning of the beater operation or intermittently or at the end of the operation. If the aqueous solution is applied to the finished paper, it may be added by spraying or by rollers or by dipping or running the paper through the conventional padding apparatus. The treated product is subsequently dried to effect cure.