Community Research and Development Information Service - CORDIS

Pulps with improved colour stability

The object of the project is to make high yield pulps with improved colour stability and to broaden the understanding of the yellowing process and its inhibition, thus promoting production of papers with improved stability from European Wood.

Various groundwood and refiner type pulps were made from softwood and several hardwood species. The influence of the pulping reagents and conditions during the manufacture on the optical and mechanical properties were established using both sulphonation and peroxide pulping. Subsequently the pulps were also bleached in various ways. The results point to the need to compromise between optimum bleaching conditions with regard to brightness and stability. The experiences led to pilot scale paper making with poplar chemithermomechanical pulp. This paper showed excellent optical properties, was successfully used for sizing and coating trials with yellowing inhibitors.

In the studies on brightness stabilization, ultraviolet screens and antioxidants were synthesized and used, together with commercial ones and then applied to pulps, pulp fractions and papers.

The output of the project was extraordinarily large and the results of the research have been spread to the pulp and paper industry in the form of reports, publications, seminars and courses. Patents have been granted and they have been offered to the industry.

Reported by

Oy Keskuslaboratorio-Centrallaboratorium Ab
Tekniikantie 2
02151 Espoo
Finland
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