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Abstract

A novel method for the production of light-stable lignocellulosic materials, in particular, the production of mechanical wood pulps with much improved light stability is described, as well as the resulting pulps of improved light stability and papers containing such pulps. The novel method involves the reaction of lignocellulosic materials such as bleached thermomechanical pulp (BTMP) with a water-soluble, fiber-reactive yellowing inhibitor possessing a primary or secondary amino (--NH.sub.2 or --NHR) functional group in an aqueous medium, or with a water-soluble, fiber-reactive hindered amine light stabilizer possessing a primary or secondary amino (--NH.sub.2 or --NHR) functional group in an alkaline peroxide bleaching medium or in an aqueous medium with a subsequent bleaching of the materials in an alkaline peroxide bleaching medium. Examples of such water-soluble, fiber-reactive yellowing inhibitors and hindered amine light stabilizers are the commercially available 4-amino-2,2,6,6-tetramethylpiperidine-N-oxyl (4-amino-TEMPO) and 4-amino-2,2,6,6-tetramethylpiperidine, respectively.

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