MORRISTOWN, NJ, Dec. 16 -- New Petra Endurance Enhanced glass-reinforced polyester
resins from Honeywell Plastics provide a balance of high fatigue strength and good
surface appearance, previously not available with high glass-reinforced compounds. The
new Petra 7300 series, and the soon to be introduced Petra 7500 series, are
post-consumer recycled polyesters and virgin polyesters, respectively.
Compared to other reinforced thermoplastic polyesters, the fatigue strength of the new
Petra Endurance Enhanced grades typically is 10 to 50 times higher. For example, the
fatigue strength of Petra 7330, at 8000-psi load, is about 240,000 cycles. Typically, a
30% glass-reinforced PET, at this load level, has a fatigue value of about 26,000
cycles. In development is a grade with still higher fatigue strength: Petra 7537, in
recent laboratory tests, exhibited a fatigue strength over 1.7 million cycles, at 8000
The high fatigue strength of the new grades is achieved while maintaining a quality
surface appearance. This capability is due to a special additive package that ensures
high quality surface appearance, said Honeywell.
The excellent melt stability and high melt flow of the new grades permit a much broader
processing window, compared to other highly reinforced polyesters. This combination of
molding traits allows large parts to be molded using the new Petra resins, as well as
thinwall parts made in molds having small gates, says the company.
A key application area is office furniture, in particular office seating. The
materials' high fatigue strength and good surface appearance make them ideal materials
for molding chairs and arm rests. The high surface smoothness of seating molded from
the Petra resins enables manufacturers to eliminate painting.
Honeywell said many furniture manufacturers are establishing specifications that
prioritize environmentally friendly materials, including the use of recycled materials
and limiting the use of materials containing regulated chemicals or other substances of