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Subject: PVA

PVA

From: Ralph Roessler <72537.3447>
Date: Friday, September 28, 1990
Hi Doug,

Reversible Adhesive #A-1023 produced by Archivart and also supplied by
Paper Technologies, Inc.  is a high-solids polyvinyl acetate homopolymer
emulsion adhesive of medium molecular weight.  The adhesive is
reversible in COLD water. The adhesive is of heavy viscosity (16000 -
18000 cps, Brookfield RVF, 20 RPM speed, 25 degress Centigrade) and can
be diluted with cold water by up to 40%, if thinner viscosities are
desired.

Like all polyvinyl acetate adhesives, this grade is sensitive to cold
temperatures and should not be exposed to tempertures below 40 degress
Fahrenheit ( this creates problems in shipping the product during the
winter ).  To the best of our knowledge, the reversibility of the
adhesive is not affected by aging of the adhesive film.

What may be of interest to ConsDist users is that apparently, nearly any
good quality polyvinyl acetate emulsion adhesive can be made reversible
to certain degree by mixing the adhesive with cold water soluble methyl
cellulose paste solution.  It appears that an addition of about 10% of
the cellulose solution is required.  From what we know, the cellulose
particles in the resulting adhesive will dissolve in COLD water and
thereby break down the film.  You may wish to make some tests in this
direction and we will be glad to discuss this matter with anyone who is
interested.

Ralph Roessler / Paper Technologies, Inc.
< 72537.3447 [at] compuserve__com >

                                  ***
                  Conservation DistList Instance 4:16
               Distributed: Saturday, September 29, 1990
                        Message Id: cdl-4-16-003
                                  ***
Received on Friday, 28 September, 1990

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