Substitute for Vinamul 3252

On behalf of Colin Johnson, Glennda Marsh-Letts
<g_marshletts [at] hotmail__com> writes

>    Vinamul3252 poly vinyl acetate/polyethylene copolymer stock
>    solution is soluble in water and acetone. It is a 57% solids
>    suspension in water: for practical purposes I regard this as
>    100% or 'full strength'. Once set it is partially soluble in
>    acetone.
>...
>    I am informed by friends at the BM (British Museum) that recent
>    batches show browning of the stock solution and a tendency to
>    stain original material (a great sin!). It is suspected that the
>    formulation has been changed. Anyway, a substitute is required!

You may want to look in to Rhoplex AC-33 by Rohm and Haas (the
equivalent in Europe is Primal, although I don't know which series).
It is an aqueous acrylic emulsion composed of a mixture of methyl
methacrylate, ethylacrylate and ethyl methacrylate polymers. The
emulsion has 46.5% solids with a pH of 9.4-9-7.  AC-33 is flexible
and non-yellowing and provides good adhesion.  Its solubility (in
acetone) upon drying has been rated medium to good.  A wall chart
product by SPNHC on "Adhesives and Consolidants in Geological and
Paleontological Conservation" can be found at,
<URL:http://www.spnhc.org/documents/leaflet2_chart.pdf>.  It might
also be worth will contacting Jane Down at CCI, as she has
undertaken a number of research projects on adhesives.

Sara Moy


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                  Conservation DistList Instance 16:70
                   Distributed: Monday, May 12, 2003
                       Message Id: cdl-16-70-004
                                  ***