MULTI-PLY WEB OF FLEXIBLE MATERIAL, SUCH AS TISSUE PAPER OR NONWOVEN, AND PRODUCT, AND METHOD FOR IMPROVING THE BLEED FASTNESS OF A FLUORESCENT WHITENING AGENT OF A MULTI-PLY WEB

摘要

The invention relates to a multi-ply web of flexible material, such as tissue paper or nonwoven material, comprising a fluorescent whitening agent. The multi-ply web comprises at least two plies being interconnected in one or more adhesive interconnection zones with an adhesive composition comprising polyvinyl alcohol, a polyaldehyde and an acid catalyst. The polyvinyl alcohol is cross-linked with the polyaldehyde such that the adhesive composition is water insoluble. The invention relates also to a method for improving the bleed fastness of a fluorescent whitening agent of a multi-ply web of flexible material, which comprises at least two plies being interconnected in one or more adhesive interconnection zones with an adhesive composition comprising polyvinyl alcohol. The method comprises a step of incorporating a polyaldehyde and an acid catalyst in the adhesive composition so as to cross-link the polyvinyl alcohol with the polyaldehyde such that the adhesive composition is made water insoluble.