Shedding light on UV
degradation in plastic aerosols
Plastic aerosols represent an innovative package platform
PARG study and test method awareness
with many industry and consumer benefits. While still
a new and developing technology, there are references
within current plastic aerosol regulation and development
requirements that can help to understand the effects of ultraviolet
(UV) degradation in plastic aerosol containers. However, few
technical references or literature are available to guide this testing.
The Plastic Aerosol Research Group (PARG)—an internationally
recognized consortium of marketers, suppliers and contract manufactures
actively involved in the global advancement of the aerosol
industry—began studying the impact of UV radiation from “real
world” environmental exposure.
PARG previously developed 19 voluntary test methods focused
on plastic aerosol container development to support regulatory test
requirements. Its membership developed an extensive study utilizing
Q-Lab Weathering Research Service to provide data leading
to two new UV test methods enabling safe testing with filled and
pressurized bottles simulating UV radiation exposure conditions.
Its intent was to drive awareness of public availability to this technical
testing, with information recently published in the Rochester
Institute of Technology (RIT) Journal of Applied Packaging Research (full
study available at scholarworks.rit.edu/japr/vol12/iss1/8/).
Setting the Stage
To the best of our knowledge, at the time of this study, no literature
was found regarding the effect(s) of Outdoor Weathering (UV
radiation) specifically related to the degradation of polyethylene
terephthalate (PET) resin containers. This study was designed
to analyze the impact to or degradation of PET subjected to and
resulting from actual UV radiation exposure through analytical
and physical testing. Additionally, we wanted to correlate the data
to develop a simulated environment methodology, using artificial
sunlight in a Xenon-Arc lamp chamber, for repeatability and to accurately
assess the impact on the plastic
aerosol container integrity. This would
provide an interested party a standard
means to make better, faster decisions
and their own risk assessment.
Testing Process & Method
Development Summary
UV exposure testing was conducted using
a one-liter PET aerosol bottle specimen
and Q-Lab Weathering Research
Service. Outdoor test specimens were
exposed for 12 months, behind single
pane glass, per ISO 877-2 method, located
at Latitude of ~25.5°N, Miami, FL,
representing a hot and humid environment
(see Figure 1). Additionally, for
correlation, test bar specimens were put
in two artificial sunlight profiles, using
Xenon-Arc light chambers (see Figure
1). Specimens were exposed initially for
50 hours, then 100-hour intervals up to
1,500 hours.
Sunlight Profile Selection
We wanted to develop a profile parameter—
to be used inside the Xenon-Arc
test chamber that could safely contain
a pressurized container in an enclosed
environment—to provide consistency
and repeatable test conditions that
would be representative of “natural”
UV solar exposure. To validate the new
Andy Franckhauser
Senior Scientist, Advanced
Packaging TPT, Procter & Gamble
“PARG
profile,”
the study was set up to compare three
exposures:
1) Using “natural” solar radiation per
ISO 877-2 method;
2) A known industry-recognized
profile using Xenon-Arc per ISO
4892-2 method; and
3) The newly created “PARG profile”
also using Xenon-Arc.
To compare the test variables, ASTM
D638 Type-V tensile bars (2.5" long x
0.375" wide) were cut from the vertical
direction of the container side walls
for applicable analytical and physical
comparison tests.
24 Spray June 2021
Dan Durham
Director, Technical Client Services,
Plastic Technologies, Inc.
Priyan Manjeshwar
Corporate Quality Technical
Manager, Plastipak Packaging
Rodney Prater
Principal, Packaging Center
of Excellence,
SC Johnson & Son, Inc.
Figure 1: Sample set-up for outdoor exposure per ISO method (left). Example of the Xenon Test Chamber (right).