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Ted Mooney, P.E. RET
Pine Beach, NJ
The authoritative public forum
for Metal Finishing since 1989
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Mold Coatings for polyurethane foam
Q. I need to find a coating that polyurethane foam does not stick to and has a reasonable life.
I am currently using a a teflon impregnated plasma coating on an aluminum mold which then filled with polyurethane foam. It works well for about 1000 shots, but then we must start applying a release agent and eventually must re-coat the molds.
What I have found so far is that the coating must have a coefficient of friction on the order of Teflon and a maximum porosity of .003".
One more catch, the coating must be harder than steel, since it is subjected to a expanded metal screen.
Thank you for your help!
Scott Walz- Bloomington, Minnesota
1999
A. I would try teflon impregnated electroless nickel. It is really smooth with very good release properties, is hard and can stand mold temperatures.
I assume that the teflon over your flame spray is a "painted" film that is a few thousandths thick. There are several different teflon formulations. Maybe a different one would get a little longer life.
Not many companies do teflon filled EN. You have several plating firms in and around Minneapolis so there may be one fairly close.
James Watts- Navarre, Florida
1999
A. Scott,
You might look into some of the PVD carbon coatings (diamond-like and diamond) which are very hard and have a low coefficient of friction.
Donald M. MattoxSociety of Vacuum Coaters
Albuquerque, New Mexico
"Handbook of Physical Vapor Deposition (PVD) Processing" (2010) [on AbeBooks or eBay or Amazon affil links]
and "The Foundations of Vacuum Coating Technology" (2018) on AbeBooks or eBay or Amazon affil links]
A. You might try a diamond-like carbon coating. This is usually put down by PVD. It is amorphous carbon, has a low coefficient of friction and has hardnesses above 2000 HV.
Have you tried other hard coatings that are popular these days? (TiN, TiAlN, CrN, etc.) Any success with them?
John Davis
- Berthoud, Colorado, USA
1999
A. Contact General Magnaplate and request information on their Nedox coating.
Mike Loy- Stockbridge, Georgia
1999
A. Scott, Diamond-like carbon (DLC) is a good candidate, which has excellent adhesion to Aluminium substrate. The friction coefficient can be less than 0.1 against steel at RH of 50% and the hardness of 20 GPa for a 2-3 µm DLC film. There are several companies can provide such coating services, such as Poeton and Son Ltd at UK.
xilin PengPhysics department, University of Wisconsin-Madison
1999
Q. I desperately need a good release agent for polyurethane foam that is being formed in a fiberglass mold. I am currently using carnuba wax and pva, but am still having serious sticking issues. I can't seem to get any good advice from the manufacturer's reps. If anyone out there has a proven solution, would you please share.
Thanks
- Atlantic Beach, Florida, USA
January 26, 2013
A. Hello,
From my experience with fiberglass molds, "Acmoscoat" is one release agent that works well.
- Montreal
August 23, 2021
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