GB1259521A - - Google Patents

Abstract

1,259,521. Papermaking. KIMBERLYCLARK CORP. 2 Jan., 1969, No. 338/69. Headings D2A and D2B. An absorbent tissue paper sheet, which may be creped, consists of a blend of fibres of two different kinds, uniformly mixed together. The fibres of one kind have little bonding capacity for one another and contain a water-insoluble, polyfunctional, polymerizable agent, which has a latent capacity for cross-linking cellulose and is developable to stiffen the fibres. The other fibres contain no cross-linking agent, have an inherent bonding capacity for each other and are bonded to each other at points of contact but these bonds are weakened by the presence of the first fibres, the bond between first and second fibres being weaker than that between the second fibres. The sheet may be made by (a) impregnating cellulosic fibres with an aqueous catalysed solution of the cross-linking agent, (b) ageing the impregnated fibres while wet with the solution to advance the agent to a water-insoluble stage, while retaining a cross-linking capacity, (c) blending the impregnated fibres with cellulosic fibres not so impregnated, to form a papermaking stock, and (d) forming a paper web by sheeting the stock and drying it under conditions to only partially cure the agent. The web may be creped either wet or dry, and may be subsequently heated to cure the cross-linking agent, eliminate the latent cross-linking capacity, and set the crepe. The cross-linking agent may be an N-methylol-urea or an N- methylol-melamine, and the catalyst ammonium chloride. The impregnated and aged pulp may, if desired be washed free of catalyst, dewatered, air-dried and stored for slurrying and use at a later time. In this case, catalyst must be added at this time unless the slurry is sufficiently acidic. Usual papermaking additives, such as wet-strength resins and defoamers may be present.