The Influence of Unbleached Pulp Content on the Permanence and Durability of Archive and Library Materials on Paper
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| Format: | Article |
| Language: | English Slovak |
| ISSN: | ISSN 0034-5806 |
| Online Access: | http://www.viks.sk/chk/res_1_02_1_14.doc |
| Abstract: | CONCLUSION. Our results, focussing on determining the effect of internal factors such as the content of unbleached sulphite and sulphate pulp on the quality of paper produced in neutral/alkaline system and using calcium carbonate as a filler, as prescribed in EN/ISO 9706 standard, indicated: ˙ All samples used for our research correspond to the particular quality properties specified by EN/ISO 9706, the standard for permanent papers. The exception is the lignin content, which is higher than allowed by the standard with all samples containing 50 % of unbleached pulp. ˙ Higher contents of lignin and hemicelluloses in unbleached sulphite pulp result in lower stability towards hydrolytic and especially oxidative decomposition; these compounds catalyse the decomposition of the cellulose molecule even without the presence of acid substances. ˙ Optical stability of paper containing higher amounts of unbleached (sulphite) pulp is unlikely; yellowness can be increased by more than 40 % if there is a higher content of unbleached (sulphite) pulp, ˙ Initial mechanical strength of the paper samples is significant. A content of more than 40 % unbleached pulp, particularly sulphite pulp, promotes the deterioration of folding endurance owing to a higher lignin and hemicellulose content. ˙ Our results confirm the necessity to use paper made of quality raw materials for books and documents requiring a permanent value. It is important to assure optimum technological conditions of manufacture, corresponding to the international standards and recommendations for permanent and archive purposes. SUMMARIES. In the framework of the research project entitled 'Permanence of Paper and Board' we checked the quality of several modern types of graphic papers. In addition, we researched the development of more permanent types of paper, including those intended for printing facsimiles, and the influence of modern conservation and restoration methods on permanence and durability of different types of paper. The project was funded by the Ministry of Science and Technology and the Ministry of Culture of the Republic of Slovenia. Our main interest was the influence of unbleached pulp content on the permanence and durability of paper produced under alkaline conditions and containing calcium carbonate as a filler, i.e. on paper fulfilling the main requirements of EN/ISO 9706, except the Kappa number limit given there. Changes in chemical, optical, surface properties and mechanical strength were evaluated and the results indicated suitable stability of the main qualities. As expected, optical stability of some samples appeared less apposite. |
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| ISSN: | ISSN 0034-5806 |
