How Packaging Labels Cause Headaches for MRF Operators

Packaging labels are important for selling products. Aesthetics play a role in consumer choice. Labels also provide crucial information for buyers.

That’s all well and good. The problem is that labels affixed to recyclable materials can wreak havoc for MRF operators. Pressure-sensitive labels and shrink wrap are particularly problematic. In worst case scenarios, the plastics they stick to—usually PET—have to be sent to landfills because they are impossible to process. And, of course, every ton that enters a MRF that cannot be repurposed represents a hit on an operator’s bottom line.

What’s the solution? Some companies see the situation as an opportunity to innovate and capitalize.

Pressure-sensitive labels are tough on PET

Traditional pressure-sensitive labels (i.e. the stickers affixed to many plastic packages) contaminate PET bottles as labels, adhesive and ink remain attached to the recycled flake.   

MRF operators typically identify PET containers, sort and bale them. Those bales go to companies who make post-consumer resin. To process the bottles, they have to wash labels off and deal with adhesives and ink. However, some containers are pulled off the recycling lines and landfilled rather than processed.

“[T]here are a lot of pressure-sensitive labels, in particular, on the market so recyclers mostly grin and bear it,” says John Standish, technical director at the Association of Plastic Recyclers (APR). “They run hot wash temperatures, using a lot of wash water and a lot of detergent. This has a big cost impact.”

APR works with brands to ensure they can meet their manufacturing requirements while guiding them toward technologies and materials that are recyclable.

The industry has seen a lot of development in pressure-sensitive labels over the last three years.

International label and package manufacturer Constantia Flexibles, NC-based UPM Raflatac, Multi-Color Corp. and CCL Label all have APR-recognized pressure-sensitive labels. Features that earn this recognition are better adhesive separation, labels that have the ability to float and use of inks that do not discolor PET.

Shrink sleeve labels are problematic

Sleeve labels—labels that surround bottles and that shrink when heated—present different challenges.

The labels can fully cover bottles. And they can be any color. It can lead to materials being sorted by the color of the label rather than the actual color of the material. It means in some cases adding a new piece of machinery to de-label bottles so they can be sorted correctly.

Shrink labels are one of the biggest challenges for Athens, Ala.-based Custom Polymers PET.

     “If you have a clear bottle with a full shrink label, the automatic color sort machines cannot identify the color of the bottle under the label. You need about 20 to 25 percent open area to properly identify the bottle,” says Byron Geiger, Customer Polymers PET president.

Further, most shrink labels are made from PETG, which is not compatible with standard PET.  PETG has a lower melting point. When the two polymers get mixed, PETG melts at PET’s standard drying temperatures and causes clumping.

“We have to pull these bottles out of the stream through our automatic sorting equipment and also manually pull them,” Geiger says. “Then they go into waste. … When the PETG shrink label gets through the system and contaminates the finished flake we have to downgrade … to lower end uses and a much reduced value.”

Emerging technologies

Companies have developed new sleeve label technology to address label issues. While some of those labels have been adopted in Europe, the technology is still in development in the U.S.

Mono-web labels are another new development where manufacturers print on a piece of plastic film. This type of label is less expensive than laminated ones, though the ink may be problematic.

“Sometimes the ink completely washes off the label. But sometimes it works, so in upcoming APR meetings we will develop guidelines for mono-web labels,” says Standish.

He adds the industry is beginning to take what it has learned with HDPE and apply it to handling labels on PE.

For now there are products like Constantia Flexibles’ SpearRC to separate the entire label from PET during standard recycling processing. Incorporated by Coca-Cola, Pepsi-Cola and subsidiaries, SpearRC allows PET resin to sink as a clean flake and be recycled. 

The label is made of polypropylene and floats (separates). The inks and adhesives remain attached to the label as to not contaminate the wash water. 

The technology “has full recognition as ‘recycle friendly’ by both the APR and the European PET Bottle Platform and full market introduction in North America and Europe,” says Dan Muenzer, vice president of marketing, Constantia Flexibles. Initial label material costs prohibited its commercialization, but C-Flex has developed proprietary materials that have enabled the product to be cost competitive with traditional pressure-sensitive constructions, he says.

Brand owners are cautious

A lack of awareness is why more brands are not turning to these products.

“Brand owners are risk-averse and want to go slowly. The perception is this is new and involves risk,” says Standish. “But they don’t have to experiment. [There is technology that] is established and on the market.”