Adhesives have, historically, posed serious problems for recyclers. Adhesives themselves are not recyclable, but the papers to which they are affixed, are. By removing the adhesives – like the ones found on the back of a postage stamp – papers become recyclable commodities.
According to Carl Houtman of the Forest Products Laboratory in Madison, WI, USA, recycling compatible adhesives (RCAs)were developed largely due to a push from the United States Postal Service (USPS). Houtman says that it all started when a group of students in the early 1990s were doing research into problems in the recycling process. They contacted the USPS about the bottlenecks found in the recycling process, which were due, to a great extent, to postage stamps. The USPS, so the story goes, took the issue very seriously.
To facilitate the creation of recycling compatible adhesives, the USPS sponsored a conference during which the adhesive industry was invited to participate in its Environmentally Benign Pressure Sensitive Adhesives for Postage Stamp Applications program. Thirteen companies participated by submitting adhesive samples. To determine whether an adhesive was recycling compatible, a protocol needed to be developed. Houtman says that the results of this work led to a three-tier evaluation process with the development of laboratory, pilot-scale and mill-scale recycling protocols.
The USPS reached out to the Forests Products Laboratory and asked the organization to develop the testing protocols that would qualify adhesives as recycling compatible (then, they were known as environmentally benign adhesives, or EBAs). EBAs were tested and qualified by the USPS specifically for their usage on postage stamps.
Houtman worked alongside Richard Oldack and Fred Gustafson to research, develop, test and promote recycling compatible adhesives. Oldack, founder of Grafton, WV, USA-based adhesive manufacturer Dyna-Tech, served as the first chairman of the Tag & Label Manufacturers Institute’s sub-committee on recycling compatible adhesives. Gustafson later assumed the role. The three worked together to educate the label industry on the importance of these adhesives, and to simplify the testing and qualifying process.
Previously, Oldack told L&NW that he wrote the testing protocols for RCAs with the label converter in mind. “Label construction differs from PS stamps in that stamps have a water-soluble barrier between the paper and the adhesive. We took the USPS EBA specification and tests from the Postal Services Specification USPS P-1238F and rewrote them to make them apply to labelstock,” Oldack said. “Usually, when you introduce a new product to the market, there are two main objections – cost and technical. The reason why I wrote several papers, published in TLMI’s Illuminator and in Progress in Paper Recycling, was to overcome the technical objections.” TLMI has since adopted the USPS EBA/RCA standards as its guideline for converters that wish to qualify their adhesives as being recycling compatible.
While Gustafson served as chairman on the TLMI sub-committee, he worked to encourage the use of recycling compatible adhesives in paper-to-paper labels. Because of his, Houtman’s and Oldack’s work, recycling compatible adhesives became commercially available and were often being used on catalogs, envelopes and in other paper applications. Gustafson was particularly excited about the impact that recycling compatible adhesives could have on the industry as a whole. “If all PSA labels were converted into recycling compatible adhesives,” he said at the time, “it would have a huge, positive impact on the paper recycling industry. Remember, paper is now more likely to be recycled than landfilled. That means more paper labels are being recycled than ever before.”
Bumps in the road
With all the momentum behind the research, development and promotion of recycling compatible adhesives, one would think that their use would be ubiquitous throughout the industry today. And that’s simply not the case.
“We’re still doing qualifications every now and again,” Houtman says, “but it really has tapered off. I just don’t think that the issue has ever risen quite to the level it needs to for the consumer. It’s the end users that really have to drive demand now.”
At the peak of recycling compatible adhesives’ popularity – about five years ago, Houtman says – the FPL was testing approximately four materials a month. Over the last two years, Houtman says that he has tested “maybe a dozen.”
According to Houtman, the reason the push for recycling compatible adhesives was so strong and so effective was because the USPS was a major force behind it. “At that time, the post office was moving away from water-activated gum to PS adhesive stamps. And the Postmaster General is a political animal, so pressure is really effective at getting them to do something. That’s what drove the postal service in this direction.”
In the years since the push for recycling compatible adhesives, though, the postal service has been plagued by financial problems – the organization has a well-documented and publicized $20 billion budget gap – which has lead to Postmaster General Patrick Donahoe to request that Congress completely reform its business model.
“The post office has been having hard times not because of stamp production, but because they have an old infrastructure and an old business model that just doesn’t really work,” Houtman says. “They have really scaled back on R&D in stamps. They were funding us to do research on compostable adhesives but that funding has been dropped. The stamp acquisition folks were keen to continue our funding, but given the financial status they were just unable to continue.”
Houtman says that he and his partners are working on new adhesives, in particular one that is made from renewable polymers that is biodegradable, but funding has been a challenge. “We’re applying for grants to keep this going,” he says.
Calvin Frost, CEO of Chicago, IL, USA-based Channeled Resources Group and an L&NW columnist, was also involved in the early stages of recycling compatible adhesives development. “When the USPS brought together a consortium of people from industry, we were brought in as the recycler, so to speak,” he says. “It took us two years, but eventually out of these meetings, trials, etc., we created the technology we have today that’s used with the postage stamp.”
Frost shares Houtman’s perspective that the demand for recycling compatible adhesives, despite the initial intensity behind it, has waned.
“We’ve pretty much reached a plateau,” he says. “Its all a matter of scale. If you take the benign technology that’s out there, if you take it to a brand owner and say, ‘We have benign PS technology, but its going to cost you more money,’ they’re not going to pay for it.
“We see it with Walmart in Canada; there was an issue recycling PET thermoform containers that have PS labels on them. Those labels for the most part are paper, and in Canada, what’s happened is that the Canadian government has said, ‘If you generate any package waste that’s not recyclable, we’re going to tax you,” Frost says. He estimates that the Canadian government has made nearly $400 million from these “eco-fees,” as they’re called.
According to Frost, once word of the eco fees got out, “Distributors said, ‘This is ridiculous; the label industry has to figure this out.’ And we have. Use a film label instead of a paper label. But it’s going to cost you 60% more. Do you think Walmart is going to spend 60% more on a little label? It comes down to price. We have the technology; but it’s all a matter of scale,” he says.
Unless there is pull from the brandowner, Frost says there is not going to be an increase in recycling compatible adhesive popularity.
“Green is the funniest thing,” he adds. “Everyone says they’re green, but as soon as it costs more, people aren’t very green anymore.”
Happily, for anyone who is truly committed to being green (or has a customer who is), there are several suppliers who offer recycling compatible adhesives – at pricing that is competitive.
Green Bay Packaging, based in Green Bay, WI, USA, offers its customers several recycling compatible adhesives, some of which were developed in response to the Canadian government’s PET thermoform recycling initiative. The company offers four stocks that meet the Association of Post-consumer Plastic Recyclers’ protocol for evaluating PET thermoform labels and adhesives for compatibility with PET recycling.
S8240760 is a semi-gloss paper with an all-temperature adhesive. It is a blue-white semi-gloss paper with an adhesive designed to work on frozen, refrigerated and shelf-stable products. S8247960 is a semi-gloss paper with a general purpose, permanent adhesive. It is designed to work on both refrigerated and shelf-stable products. S8247560 is a semi-gloss paper with an aggressive permanent adhesive designed for shelf-stable products. Finally, S8247860 is a top-coated direct thermal paper with a general purpose, permanent adhesive. It is designed to work on refrigerated and shelf-stable products.
Green Bay Packaging also offers two recycling compatible adhesives that meet the Tag and Label Manufacturers Institute testing protocol RCA LRP 2v5. For those who need a general-purpose, permanent adhesive, 760S is available. And for applications where a hard, repositionable adhesive is required, the company offers 548S. 760S is available in high-gloss, semi-gloss (54# and 60#), dull litho, EDP, recycled laser jet and select thermal transfer. 548S is available in semi-gloss. The company says that custom structures can be created with each of these adhesives.
Franklin Adhesives & Polymers, a division of Franklin International, manufactures adhesives for wood furniture, millwork, engineered-lamination and filter-fabrication markets. The Columbus, OH, USA-based company currently offers two pressure sensitive adhesives that are certified by the Forest Products Laboratory as recycling compatible.
Covinax 324-39 is a vinyl acrylic co-polymer for general-purpose permanent pressure sensitive adhesives on tapes and labels. It is used for corrugated substrates, polyolefin films, glass and metals and is easily converted into rolls or sheets without sticky edge problems. This formula can be transfer-coated on most rod, gravure or roll coaters.
Covinax 379-05 is an acrylic adhesive for permanent pressure sensitive applications, including pharmaceutical label applications curved or irregularly shaped surfaces. The balance between peel and shear strength also renders this formula easily convertible to rolls or sheets. It is specifically designed to be transfer-coated on slot die coaters and can be used on most rod or roll coaters. Both adhesives also are FDA compliant under 21CFR 175.105.
UPM Raflatac, a global supplier of pressure sensitive label materials based in Mills River, NC, USA, offers its customers both a permanent recycling compatible adhesive and a water-washable, permanent adhesive approved for use on PET thermoform packaging.
EB34 is a permanent recycling compatible adhesive that meets the TLMI LRP-2 qualifications. This adhesive can be filtered (screened) on the recycling paper process. It is intended for use on paper-to-paper labels.
The company’s RP45 products affix permanently to a variety of materials, but can be easily removed from packaging with warm or hot water wash-off. They can be cleanly removed from food and beverage containers, such as beer kegs, and the Association of Postconsumer Plastic Recyclers (APR) has approved them for use on PET clamshell packaging. Specifically, APR has added SP184W, UPM Raflatac’s 54# Raflacoat facestock paired with RP45 adhesive and a 40# White Kraft (2.5 mil) liner to its list of products that conform to its protocol for evaluating PET thermoform labels and adhesives for compatibility with PET recycling.
According to UPM Raflatac, “APR used a rigorous, seven-part laboratory test to verify that this product can be satisfactorily removed for PET thermoforms via warm or hot water wash-off. Passing the test is a strong indicator that a labeled clamshell can be successfully recycled along with PET bottles. Therefore, brand owners and packages can now offer their grocery and other retail customers a sustainable food packaging solution.”