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Re: Methyl Cellulose grades



Our learned colleague has written:

>there are many grades of methyl cellulose - contact a
>manufacturer (DOW Chemical, for one) and get their technical
>data sheets to learn which formula is right for your purpose.

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Indeed.  If the correct methyl cellulose grade is not used, the
resulting effect may be less than desired, or not work at all, or have a
negative effect.

Methyl cellulose is used extensively throughout industry, for such
purposes ranging from paint thickeners, to industrial sizes and
coatings, to ice-cream thickeners.  Many food products found in the
supermarket have methyl cellulose as an ingredient in one form or
another.  The people in the industry see it as a marvellous and
ubiquitous modern product.

There are many grades of methyl cellulose.  When considering the grade
of methyl cellulose to use, one must consider the use to which it will
be put.  The use of methyl cellulose as a sizing agent has been written
up in the [UK's] Institute of Paper Conservation's Manchester Conference
Papers 1992.  Amongst the many and varied papers presented, there were
seven papers dealing with the subject of sizing and resizing.  All are
worth reading, but the one pertinent to the subject under discussion is
"The role viscosity grade plays when choosing methylcellulose as a
sizing agent", by Cathleen Baker.

One has to consider using one grade of methyl cellulose for surface
sizing, and another grade for immersion sizing.  The differences may not
always be apparent, but with jobs that are more delicate, one does see
results which differ, and further study and tests are worthwhile.  Then
one sees, for instance, (and this will put a spanner in the works) that
a thicker mixture does not always mean a more concentrated solution.
It depends on the crystalline structure of the methyl cellulose grade
being used.

When considering methyl cellulose as a light adhesive, differing
criteria are present.  The abovementioned article gives useful technical
information on the differing grades for use with paper, and also touches
on
the use of methyl cellulose as an adhesive.  One may then choose the
appropriate methyl cellulose grade.  We have 3 or 4 grades here, and use
them variously, sometimes combined, sometimes not.

But try it out for yourself.  Obtain the technical booklets from Dow,
with their graphs and tables, and experiment with fine tissues to enable
the different results to be made more apparent to you with the naked
eye.

There is nothing like using the wrong methyl cellulose grade, or using
it at the inappropriate concentration, and then finding, for instance,
that the film of dried methyl cellulose is thicker than the medium one
is gluing or resizing, the result being that the whole medium cracks and
breaks!

We have written this rather hurriedly, and some aspects were only
touched upon, perhaps causing a little confusion, and for this we
apologise.  Our bench is calling us .......

(Jack, are you with us here!)


Peter Krantz.

************************************************
Book Restorations.
34 Clanville Road,
Roseville,
N.S.W.        2069,
Australia.

(P.O. Box 500,  North Sydney,  N.S.W.  2059.)

Telephone:  +61 2 9416.9900
Fax:  +61 2 9416.6800
Email:  bkfndrs@ozemail.com.au

Established:  1976

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