Bookbinding leather in the paper deacidification process. Part I. Analytical investigation of the leather
| Main Authors: | , , , |
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| Format: | Book Chapter |
| Language: | English Slovak |
| ISBN: | ISBN 1-84407-253-3 |
| Online Access: | http://www.viks.sk/chk/14tmh_36.doc |
| Abstract: | SUMMARIES. The non-aqueous ‘papersave swiss’ process is used for paper deacidification. This treatment may cause damage to vegetable tanned leathers. To assess this process, historic, new and new artificially aged materials were analysed using various methods. Positive effects observed are the complete neutralization of acids in historic leathers and an increase in hydrothermal stability of new ones. Negative effects are a decrease in hydrothermal stability of historic leathers, extraction of fat compounds and stiffening of the leathers. Moreover, the deacidification effects may depend on the tannin type. Multiple regression modelling suggests two different breakdown patterns for deacidified and untreated leathers, respectively. CONCLUSIONS. The effect of the deacidification on vegetable tanned leathers depends on the type of tannin. Thus leathers tanned with hydrolysable tannins seem to be more resistant to deterioration than leathers containing condensed tannins. This is supported by multiple regression modelling of the shrinkage temperature vs. data from amino acid analysis, tannin analysis, the amount of soluble sulphate and the acidity in the leather. The modelling results in significant prediction of the shrinkage temperature and suggests two different breakdown patterns for the two main types of leathers, hydrolysable and condensed. Moreover, the effects of deacidification are both positive and negative. The positive effects are first of all the complete deacidification of acids in the historic leathers and increase in hydrothermal stability of the new leathers. On the negative side are the mechanical properties and slight decrease in durability, the decrease in hydrothermal stability of the historic leathers, the extraction of fat compounds and the general stiffening of the leathers. This means that the leather part of a book binding may be in danger of being affected negatively by this type of deacidification treatment. Open questions concern the extraction of tannin in the deacidification liquid, the reaction of chrome-tanned leather bindings and the reduction or repair of the stiffening of leather bindings. It is our hope that these questions can be answered in a future joint project. |
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| ISBN: | ISBN 1-84407-253-3 |
