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Subject: Coroplast

Coroplast

From: Paul Storch <paul.storch>
Date: Wednesday, August 20, 2003
Pete Sixbey was told that Coroplast could be causing allergic
reactions in museum technicians working in close proximity to it
(see Conservation DistList Instance: 17:21 Monday, August 18, 2003).
The Coroplast is used as shelving in new cabinets, and given the
information about the other components and the reactions, I would
find it very unlikely that the Coroplast is the culprit. Coroplast
is polypropylene, and unless the shelves are not genuine Coroplast,
there would be no VOC's to detect.

Pete mentioned noticing a strong acidic odor in the cabinets and
vicinity.  I would find it surprising, but not totally out of the
realm of possibility, that the cabinet manufacturer used an
acetoxy-curing silicone as a caulking or gasket material somewhere
in the structure.  This would be the source of the acid smell.  One
way to confirm that is to place IPI A-D strips inside the cabinet
for a semi-qualitative determination of the acetic acid
concentration.

I would suggest obtaining a copy of CCI's Technical Bulletin #21
"Coatings for Display and Storage in Museums" and applying the
various qualitative tests that they include in the appendices.  The
bulletin has protocols for testing cabinetry and assessing this type
of problem.

Given my previous experience with a very similar cabinetry problem,
I would say that it is the gasketing material that is the source of
the odor and the reaction.  The MHS had purchased a large number of
standard and custom-built storage cabinets from a prominent
manufacturer.  After delivery and set-up, we kept noticing a strong
solvent odor inside the cabinets. After contacting the company
president, we agreed to do some testing to determine the problem.  I
sampled both the gasketing and the drawer slide grease and submitted
the samples to a local IAQ lab in St. Paul, Legend Technical
Services, for head-space analysis.  The silicone-rubber gasket came
back positive for uncured silanol monomer and relatively large
amounts of 1,1,1-trichloroethane solvent.  The solution was to
replace the existing gasketing with food-grade, post-cured silicone
rubber.  That was done, and we later had the gasketing re-checked by
the same lab and found no monomer or solvent.

If the manufacturer continues to blame the problem on another
product and is uncooperative, I would suggest submitting samples of
each of the suspect materials to either a state IAQ lab or a
commercial firm to identify the chemical agents responsible for the
reactions.  You might also want to look at other sensitizing
sources, such as mold, but the reactions seem to be correlated with
the cabinets.

Paul S. Storch
Senior/Lead Objects Conservator
Daniels Objects Conservation Laboratory (DOCL)
B-109.1, Minnesota History Center
345 Kellogg Blvd. West
St. Paul, MN  55102-1906
651-297-5774
Fax: 651-297-2967


                                  ***
                  Conservation DistList Instance 17:22
                 Distributed: Thursday, August 21, 2003
                       Message Id: cdl-17-22-001
                                  ***
Received on Wednesday, 20 August, 2003

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