Re: spot cleaning walls in gallery

[Scott Williams <Scott_Williams@xxxxxxxxx>]

This message refers to Judy Schwender's
query about Mr. Clean Magic Eraser, and Mary Ballard's response.  Both
messages contain errors or misleading statements regarding the composition
and hazards of the product.

The MSDS referred to by Schwender states:
Ingredients/Chemical Name: Formaldehyde-Melamine-Sodium
Bisulfite Copolymer
and
Hazardous Ingredients as defined by
OSHA, 29 CFR 1910.1200., and/or WHMIS under the HPA: None
and 
Unusual Fire Hazards : Dust/air mixture
may explode

Please note that this product contains
a copolymer made from formaldehyde, melamine, and sodium bisulfite, but
does not contain the unreacted starting materials, as stated by Schwender.
 Thus the MSDS statement that there are no hazardous ingredients is
correct.  Ballard is correct in her description of the hazards of
the starting materials, but since none of these are present in the product,
her concerns are irrelevant for this product.  

Ballard's highlighting of the MSDS statement
that the product has the unusual hazard that "dust/air mixtures may
explode" is misleading because it implies that this might be a significant
hazard during use of the product, which is incorrect.  The "unusual
hazard" referred to is actually stated on the MSDS as an "Unusual
Fire Hazard" in the MSDS section on Fire Fighting Information.  
Dust/air mixture of all organic and many inorganic powders might explode
if the conditions are right (http://www.reade.com/Safety/dust.html). Therefore
a phrase such as this is common on MSDS for powdered materials.  For
example, an MSDS for starch (http://www.jtbaker.com/msds/englishhtml/s6506.htm)
contains the following phrase in the Fire Fighting Measures section: "Explosion:
Fine dust dispersed in air in sufficient concentrations, and in the presence
of an ignition source is a potential dust explosion hazard. Minimum ignition
temperature, cloud: 430C (806F)".  This does not cause us undue
concern when we prepare starch pastes and apply them to flammable objects
like paper.  MSDS sheets are invaluable and readily available sources
of information on products, but the information must be read and evaluated
in context.  How much dust would you expect to be produced during
use of a wet sponge measuring 1 x 2.5 x 5 inches?

I recently analyzed this product and
my results with some additional comments follow.

Report on the analysis of Mr. Clean
Magic Eraser, by Scott Williams, CCI:

The eraser is composed of a foam made
of melamine-formaldehyde polymer.  (After reading the MSDS, I think
this should be amended to read as "made of melamine-formaldehyde-sodium
bisulfite copolymer" , which probably has an IR spectrum very similar
to MF polymer).  I think the efficacy of the eraser is related to
the abrasiveness of the sponge.  This is supported by the fact that
IR spectra of the product match the clear tough abrasion resistant topcoats
on Arborite and Formica.  According to the Encyclopedia of Polymer
Science and Engineering, melamine-formaldehyde is the hardest commercial
plastic material.

The mode of cleaning action of this
foam is described at  http://www.sunpowerusa.com/whismefo.html .  I
do not know who supplied the information, but this seems reasonable.  The
individual fibres of the sponge are visible with a stereo microscope, so
they are about the thickness of a hair, which is not extraordinarily fine.

Colleagues have noted that Magic Eraser
scratched acrylic sheet and removed the gloss from glossy paint.  The
Mr Clean web site (http://www.homemadesimple.com/mrclean/tips.shtml#eraser
) warns: "The Mr. Clean Magic Eraser is a highly effective cleaning
tool. Test first on an inconspicuous spot with light pressure to see if
surface may scratch or dull. Not recommended for use on surfaces that are
polished/glossy, or on brushed, satin, dark, or faux finishes. Do not use
with chlorine bleach."

The foam is a reticulated foam.  It
consists of just the pillars of material that form at the intersection
of cells in a foam.  In a reticulated foam the windows between adjacent
cells are absent and only the pillars remain.  A cross-section of
such a foam, which looks just like Magic Eraser, is shown at http://www.jm.com/corporate/labs_services/2337.htm
(scale unknown) and http://www2.basf.de/basf2/html/plastics/englisch/pages/presse/04_260.htm#.
This latter page describes the product as "abrasive and hard".

SEM micrographs comparing melamine foam
to urethane foam are at http://www.univ-lemans.fr/~r940020/en/porous_media/
.  Note all the sharp pokey ends of fibres.  I think these work
like chisels, in the same way as bristles on a glass fibre bristle brush.
 The fibres slice, scrape and abrade, then the detritus produced is
trapped in the cells, to be washed out later.  

According BasoTect website (http://www2.basf.de/basf2/html/plastics/englisch/pages/presse/04_260.htm
) the fibres are 6 micrometer diameter and maintain the "extraordinary
hardness of melamine resins while yet coming up with a soft flexible foam".
 I note that Magic Eraser is made in Germany.  BasoTect is made
by BASF. BASF is producing Basotect® in Ludwigshafen and Schwarzheide,
from where it is shipped to customers worldwide in the form of large blocks
for subsequent transformation into an enormous variety of items.

Consumer info is given at http://www.sptimes.com/2004/07/24/Homes/A_hand_for_Mr_Clean.shtml
.  This says that the eraser is used wet so that it sticks to the
substrate better (like a wetted finger to turn a page).  I think this
due to a surface tension effect that pulls the sponge fibres into contact
with the substrate surface.  Also this says that the eraser crumbles
slightly with each use.  This would expose new pokey ends to do more
abrasion.  Also, some might be left behind on the object, especially
if used dry.

Apparently the really big user of melamine
formaldehyde foam (usually called just melamine foam) is in acoustic applications,
e.g, sound absorbing ceiling tiles  http://www.acousticalsurfaces.com/acoust_ceilings/white.htm?d=20

In conclusion, I suspect this works
solely by abrasive action.  I doubt there is anything else in the
sponge, but I cannot confirm this because no extractions were performed.
 

End of report.

A product with a similar description
(but not analyzed by me) called Extreme Sponge is available (http://www.xtremesponge.com/index.htm
).

R. Scott Williams
Senior Conservation Scientist (Chemist)
Conservation Research Division
Canadian Conservation Institute
1030 Innes Road
Ottawa, Ontario, Canada K1A 0M5
tel: (613) 998-3721
fax: (613) 998-4721
email: scott_williams@xxxxxxxxx

Visit the CCI Web sites at www.cci-icc.gc.ca and www.preservation.gc.ca

--------------------
>>>Mary Ballard <BallardM@xxxxxxxxxxxx>
Judy Schwender: Do you really want to use something in your galleries that
lists as an unusual hazard that its "dust/air mixture may explode"? Sodium
bisulfite is a mild reducing or stripping agent; its eventual oxidation may
release sulfuric acid. It may be that the compound is described in its
pre-polymerized components: formaldehyde has a very low TLV (if you can
smell it, it's now way over the limit); melamine is the English trade name
term for formica. Maybe you should talk directly with a P&G technical
representative--or your paint store. Best wishes, Mary Ballard

>>> sister3603@xxxxxxxxx 11/22/2005 12:30:39 PM >>>
Greetings-
 We would like to spot clean some walls in our quilt gallery, and the Mr.
Clean Magic Eraser has been suggested by a board member.
 According to the Material Data Safety Sheet (found at
http://www.pg.com/content/pdf/01_about_pg/msds/fabric_and_homecare/hard_surface_cleaners/Mr_Clean_Magic_Eraser.PDF)
 this product contains formaldehyde, melamine, and sodium bisulfite
copolymer.  We would spot clean drywall that has been painted with latex
paint.  Nearby quilts would not be removed during application.  Quilts might
be hung over treated areas at a later date, perhaps 4 months from now.
 Does anyone have any experience with this product?  Do you have any other
suggestions for products that would safely work?
 Thank you so much-
 Judy Schwender
 Curator of Collections / Registrar
 Museum of the American Quilter's Society
 Paducah, Kentucky
 USA
 270-442-8856  x30

Mary Ballard <BallardM@xxxxxxxxxxxx>
Sent by: Textile Conservators <TEXCONS@xxxxxxxxxxxxxxxxxx>

2005-11-22 02:37 PM

Please respond to
Textile Conservators <TEXCONS@xxxxxxxxxxxxxxxxxx>

To	TEXCONS@xxxxxxxxxxxxxxxxxx
cc
Subject	Re: spot cleaning walls in gallery

Mary Ballard <BallardM@xxxxxxxxxxxx>
Judy Schwender: Do you really want to use something in your galleries that
lists as an unusual hazard that its "dust/air mixture may explode"? Sodium
bisulfite is a mild reducing or stripping agent; its eventual oxidation may
release sulfuric acid. It may be that the compound is described in its
pre-polymerized components: formaldehyde has a very low TLV (if you can
smell it, it's now way over the limit); melamine is the English trade name
term for formica. Maybe you should talk directly with a P&G technical
representative--or your paint store. Best wishes, Mary Ballard

>>> sister3603@xxxxxxxxx 11/22/2005 12:30:39 PM >>>
Greetings-
 We would like to spot clean some walls in our quilt gallery, and the Mr.
Clean Magic Eraser has been suggested by a board member.
 According to the Material Data Safety Sheet (found at
http://www.pg.com/content/pdf/01_about_pg/msds/fabric_and_homecare/hard_surface_cleaners/Mr_Clean_Magic_Eraser.PDF)
 this product contains formaldehyde, melamine, and sodium bisulfite
copolymer.  We would spot clean drywall that has been painted with latex
paint.  Nearby quilts would not be removed during application.  Quilts might
be hung over treated areas at a later date, perhaps 4 months from now.
 Does anyone have any experience with this product?  Do you have any other
suggestions for products that would safely work?
 Thank you so much-
 Judy Schwender
 Curator of Collections / Registrar
 Museum of the American Quilter's Society
 Paducah, Kentucky
 USA
 270-442-8856  x30



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