ipcm® n. 71 - September/October 2021

Page 50

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