SUSTAINABILITY
SPECIAL ISSUE ON ARCHITECTURE & DESIGN
Powdura ECO Powder Coatings: from Plastic to Powder The Sherwin-Williams scientists developed a new process which converts plastic waste into a durable, high-performing polyester resin that contains 25% pre-consumer recycled plastic (rPET).
T
he issue of plastic waste polluting our oceans is well documented
(polyethylene terephthalate) contains the same monomers (building
and reported to be around 12 million tonnes of pollution each
blocks of polymers) as the resins used in the binders of powder coatings. The novel process the scientists developed to capture and stitch these
year - this is the equivalent of > 700 billion plastic water bottles . 1
Why is this happening? Plastic is cheap, strong, lightweight and malleable
monomers directly into the backbone of the Powdura ECO powder
making it ideal for single-use plastic containers, which have been widely
coating resin not only reduces the environmental footprint of the coating
adopted as a convenient way to package and carry food and drinks. Once
by 20%, as demonstrated in life cycle analyses, but the resulting coating
the contents are consumed the container is discarded as waste that
has the same protective, decorative and functional properties as a
eventually makes its way, via the waste cycle, into the oceans.
product made from virgin resin’.
Many polymers are difficult or expensive to recycle, however the
The Sherwin-Williams scientists put Powdura ECO through its paces,
scientists at The Sherwin-Williams Company have found a way to re-
probing the performance with an exhaustive array of mechanical,
purpose the polymer used to manufacture plastic water bottles and
environmental and chemical tests against a class-leading control with the
convert it into a powder coating. Powder coatings are amongst the
results in the table below exceeding expectations.
most sustainable coatings available as they contain no VOCs and have
As the recycled material is polymerised into the resin backbone this gives
utilisation rates >95%. ‘Using pre-consumer PET waste that would
a wide degree of formulation flexibility with Powdura ECO being offered
normally go to landfill and recycling it into a functional coating that
in a full range of colors, gloss levels, effect and textured finishes.
is used to protect products from corrosion, extending their service
The incorporation of recycled PET, the equivalent of 35 plastic bottles
life, makes perfect sense’ explained Aliette Brochier, Product Director
per kg, into Powdura Eco translates into quantifiable environmental
of The Sherwin-Williams Company. ‘Not only does this support the
benefits, creating a competitive advantage for manufacturers looking to
circular economy by recycling waste material, but it further reduces
achieve corporate sustainability targets, differentiate their products in the
the environmental footprint of powder coatings by capturing the
market-place or meet the requirements of third-party certifications such
good carbon contained in the waste PET’, she went on to explain. ‘PET
as LEED, BREEAM, GREENGUARD and GBB.
“Plastic Waste Inputs from Land into The Ocean”, Science, Feb. 2015, Vol. 347, Issue 6223, pg. 768-771.
For further information: https://industrial.sherwin.eu
1
Powdura ECO’s tests results.
42
TEST PROPERTY
TEST METHOD
POWDURA ECO
Smoothness Rating @ 2.0 mils
PCI #20
≥6
Impact (Direct/Reverse)
ASTM D2794
160/160 in. lbs.
Conical Mandrel Bend
ASTM D522
1/8” No Cracking
Pencil Hardness
ASTM D3363
≥2H
Crosshatch Adhesion
ASTM D3359
100% (5B)
Re-coat Adhesion
ASTM D3359
100% (5B)
Chemical Resistance (100% MEK)
PCI #8
Pass
Humidity Resistance (500 hrs.)
ASTM D2247
Blister Rating: 10, no blisters Rust Rating: 10, no rust
Salt Spray Resistance (500 hrs.)
ASTM B117
Avg. creep from scribe = <1.0 mm Blister Rating = 10, no blisters Rust Rating = 10, no rust
Xenon Resistance (500 hours)
ASTM G155
60° Gloss Retention = ≥85% - ∆E = ≤1.0
N. 71 - SEPTEMBER/OCTOBER 2021 - international PAINT&COATING magazine
