February 27, 2018 - Plastics News
APR in the News
California rules: No more No. 1 resin code for PETG
When is PET not PET? When it is PETG.
To the typical consumer, the difference between PET and glycol-modified PET is simply a letter.
But to a polymer scientist worth her molecular weight, there’s a huge difference. Especially when it comes to recycling.
And that’s why the Association of Plastic Recyclers worked for years to clarify that difference in California, culminating in the recent passage of a new law that defines exactly what constitutes PET.
A workhorse of the container business, PET is the most recycled resin, especially in bottle bill states like California, where there is a financial incentive to recapture the material.
The resin identification code for years has labeled PET as a No. 1. But some PETG-container makers also have been putting a No. 1 code on their products.
And that’s a problem because PET and PETG perform differently during the recycling process, explained APR Technical Director John Standish.
“It’s distinctly different,” he said. “It might sound silly, but people go, ‘It’s polyester, and all polyesters are the same.’ And no, they are not.”
PETG flakes, when recycled, end up glomming on to PET flake to create clumps that disrupt processes and equipment.
“PETG is a copolymer. So it’s a polyester. But it’s a different composition than the PET that’s used to make injection stretch blow molded bottles, which are what a Coke bottle, a Pepsi bottle, a single-serve water bottle [are made from],” Standish said.
The introduction of glycol to create PETG from PET creates a distinct material, one that performs differently during processing as well as recycling.
PETG, in the thermoformed container market, is used in food packaging. It’s also frequently used to package medical devices and electronics.
It’s typically a shade of blue in thermoformed medical applications, and not typically found in the recycling stream, Standish explained.
“All we really did in California, we introduced a piece of legislation that really clarified their existing law,” APR Executive Director Steve Alexander said. “All we did was just reinforce the definition of what PET was for the purposes of the resin identification code in California.”
Read the full article from Plastics News here.