Pyroxylin on paper

Claire Hoevel has requested for information about pyroxylin and its
reaction on paper. She has already got her answer from Stephen Koob,
so I don't bring her any more comments on that. But, she writes in
here letter that pyroxylin is used in library bindings to increase
durability.

I was nearly saying: I hope not! Pyroxylin has of course nothing to
do with durability, as we know it to day. So I think it needs some
explanation.

Pyroxylin was used in bookbinding in order to give the cloth on the
book covers more strength and a more resistant surface. But the
instability of pyroxylin didn't bring that strength to the covers.
Instead it brought new problems, like the tendency to "glue" the
books together with each other, when they were standing on the
shelves in the Library. The flexibility of the cloth decreased quite
rapidly and the covers  broke in the hinges. Another big problem was
the increased risk for fire (not that it would start to burn by it
self, but that the books would burn more easily).

Nowadays the manufactures normally uses an acrylic resin for the
same purpose as above. Acrylic compounds has compared with pyroxylin
good chemical stability and should for that reason not show similar
problems.

Lars Bjordal
Conservator
Uppsala University Library
Sweden

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                  Conservation DistList Instance 9:62
                 Distributed: Thursday, March 14, 1996
                        Message Id: cdl-9-62-012
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