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GBlist: PF resins



Hal, Mike and GB listers:

I would like to add to the discussion on phenol-formaldehyde resins by
pointing out that formaldehyde-free resins can also be made and used as
adhesives for composite building materials, such as plywood and
particleboard.

As you know, conventional phenolic resins are manufactured with
formaldehyde (toxic petrochemical) used to link phenol molecules
together.  The presence of unreacted phenol and formaldehyde in these
resins is an environmental problem because these compounds are VOC's. 
Actually, 10-40% of the formaldehyde evaporates from these resins (we
all know the health risks associated with these emissions).
Two main functional problems are also associated with PF resins:
1) There are unstable; they deteriorate and turn yellow when exposed to
heat and light.
2) The must be dissolved in large amounts of petroleum-based solvents.

Formaldehyde free resins can be made with the addition of a natural
catalyst, a peroxidase enzyme, with which the phenol molecules can be
linked together directly, thus eliminating the need for formaldehyde.

The peroxidase technology was developed by Enzymol International
(Columbus, OH) and based on an enzyme that is derived from soybeans. 
The peroxidase enzymes are produced by a variety of plants, fungi and
microbes.  However the soybean-derived peroxidase exhibits superior
thermal stability and a variety of useful reactive properties.  There
advantages include:
1) For one, it eliminates the use of formaldehyde as a bridge.  This
offers a functional advantage to the resin because this bridge is the
site most susceptible to chemical reactions with oxygen and degradation
induced by heat and light.  Therefore, formaldehyde free resins are more
stable and resistant to yellowing.
2) The systhesis reactions are also milder and more efficient.  They
occur at temperatures 100-150F lower and 4-5 hours faster than the
conventional process.
3) They also have more complete reactions that results in 10-40% higher
product yields.

Overall benefits include: economic factors such as reduces processing
times and higher product yields, lowering VOC's by eliminating
formaldehyde, and providing a safer work environment.

I also enjoy the added benefit of utilizing a biologically-derived
material versus a petroleum derived one.  This not only avoids the
upstream pollution generated with the extraction of oil, but also allows
for cleaner processing and supports our agricultural communities.

Thanks,
Michelle Carstensen
Research Associate
Instutite for Local Self-Reliance
Website: http://www.ilsr.org
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