Extruder OEMs SML, Kuhne and Gneuss report that packaging makers are shifting to greener materials, demand for packaging has risen due to the pandemic and equipment sales are strong.
SML: Strong demand for sheet lines
“The two megatrends from my view are the recyclability and the sustainability of the packaging and the avoidance of plastic,” said Martin Kaltenecker, sales manager at SML Extrusion Technology in Austria, which manufactures cast film, sheet and coating equipment.
Demand for more recycled content, coupled with low interest rates and government subsidies in some countries, is fueling strong demand for film and sheet lines to produce packaging for consumer goods.
“There is a lot of cheap money in the market and there are a lot of subsidies in many countries, too, so companies think now is a good time to invest [in new equipment],” Kaltenecker said.
Many older extrusion lines were not designed for recycling large amounts of plastic, extruding very thin layers of film or handling some modern polymers, Kaltenecker said.
“In former days, often the in-house recycled material was used in downcycling — it was used in different applications, not in the product itself,” Kaltenecker said. “It was going to blown film or to injection molding or whatever. Nowadays, the target is clearly that you reuse the material in the same product as you produced it originally.”
In addition, in some markets, post-consumer LLDPE stretch film is being collected from large distribution centers and warehouses and recycled into new stretch film, he said.
“This is one of the points we are focusing on at the moment, building stretch-film lines with extruders with dedicated dosing systems that can feed back the pelletized, washed, post-consumer recycled material into a new stretch film,” Kaltenecker said.
Recycling LLDPE stretch film with older extrusion lines can be a problem because they may only be able to produce three-layer film, whereas for optimum performance, four or five layers are required, allowing the recycled material to be sandwiched between layers of virgin polymer with different properties.
The pandemic, meanwhile, has highlighted the importance of plastic packaging, Kaltenecker said.
The primary function of packaging is protecting a product, and everything else is an additional function, he said.
“What we have seen in the past one-and-a-half years is this protection became more important due to the COVID crisis and hygiene [concerns],” Kaltenecker said. “There was an emphasis on everything being kept clean and not contaminated.”
Additionally, demand for single-product packaging has grown since the start of the pandemic.
“What drove that was people were no longer eating in restaurants,” said Mark Jones, SML’s director of support services in North America. “They would stay at home, and there was a big increase in demand for already-prepared meals.”
And, despite so-called “green pressures” on plastic packaging, U.S. sales are strong. “There is some stocking up [of packaged goods] in anticipation of higher prices,” Jones said. “The base requirement for things like stretch wrap seems to be higher.”
A strong market for stretch wrap also contributes to growing sales of film extrusion lines.
“A lot of companies are not just replacing old equipment because the old equipment is less efficient, they’re putting in new equipment and keeping the old equipment up and running because they don’t have the capacity,” Jones said. “We know several manufacturers who can no longer meet demand.”
Companies also continue to look at what many consumers consider green alternatives to plastic. For example, SML had a couple of projects with paper manufacturers for equipment to coat paper packaging with very thin LDPE layers, Kaltenecker said.
Kuhne: Mono-material easier to recycle
Interest in mono-material packaging, typically PE or PP, also is on the rise, said Adolfo Edgar, VP of blown film systems for Kuhne Anlagenbau GmbH in the U.S. and Canada.
“The term ‘mono-material’ can be deceiving because up to 5 percent of a different but miscible material is allowed in the packaging,” Edgar said. “This is the case of EVOH, which is used to provide an oxygen barrier.”
Limiting packaging to one material can make it easier to recycle.
“Most plastics used in packaging are recyclable, but the problem is they tend to be coextruded or laminated to other plastics, making recyclability difficult or cost-prohibitive,” Edgar said. “In addition, you have the issues of inks, adhesives, pigments, etc.”
Producing mono-material films can be challenging. It may require new equipment, but often existing equipment can handle the material change.
“In many cases, existing equipment can be used without or with minor modifications like a different extrusion screw, for example,” Edgar said. “In other cases, OEMs have to modify their equipment. For example, our Triple Bubble technology [for multilayer, biaxially oriented barrier films] is now being used to produce PO (polyolefin)-based barrier structures for applications like lidding films, stand-up pouches, bottom-forming webs, form-shrink bottom-forming webs and shrink bags. To achieve this, we had to develop new hardware that would allow the production of these PO-based films. When you are not able to use PET or PA [polyamide] in a Triple Bubble structure, the stability of the process becomes a challenge. This is what we were able to overcome.”
Depending on the configuration, existing Triple Bubble lines can be retrofitted to run the films, he said.
Brand owners also are asking for more recycled content in their packaging, but quality recycled resin often is in short supply, Edgar said.
“There are not enough reliable sources of clean recycled plastic,” he said. “The only good option so far is the PET bottle, which remains relatively clean, is easy to sort and the technology to reprocess it is quite mature.”
Bioplastics — biodegradable plastics derived from biological substances rather than petroleum — also are making some inroads but face challenges.
“There are limitations in the performance of bioplastics compared to traditional ones,” Edgar said. “Also, cost and supply are issues. They are more expensive and there would not be enough supply to satisfy the demand if they were to gain traction.”
Gneuss: Decontaminating recycled material
“All over the world, there is a trend to get more and more recycled material,” said Carl-Jürgen Wefelmeier, head of the business unit for sheet at Gneuss, headquartered in Germany. “This is very positive for us as an equipment supplier for recycling machinery, both filtration systems and extrusion systems. This is a very big trend.”
Gneuss sells extrusion systems and turnkey sheet lines for recycling PET, PS and other plastics.
Recycled material is not the same quality as virgin, so processors need to efficiently decontaminate post-consumer PET to produce food-grade sheet, Wefelmeier said. Often, this means purchasing special equipment.
“This is what we are doing,” Wefelmeier said. “We manufacture a special extrusion system, which is able to decontaminate the input material and to clean the input material.”
Gneuss’ MRS extruders are designed to degas and decontaminate post-consumer plastics. The single-screw extruders have a section containing multiple satellite screws that enlarge the melt surface under vacuum. This provides devolatilization that is 100 times greater than a traditional single-screw extruder, the company said. The extruders are especially suited for recycling hygroscopic polymers and resins that require a high degree of devolatilization.
Typically, processors have used MRS extruders to recycle bottle flakes into PET sheet for thermoformed food trays or other packaging.
However, Gneuss foresees a growing market for recycling other materials on its MRS extruders as PET bottle flakes become more difficult to obtain because of growing demand.
“It’s interesting to see that the sources [of recycled PET] are changing a bit,” Wefelmeier said. “Bottle flakes are getting less and less available. We are thinking in the future about different material sources for post-consumer recycling.”
Right now, PET bottle flake dominates the recycling market. However, interest in recycling post-consumer PET trays — and PS trays — is growing.
Gneuss has a customer in Japan that is collecting PS trays used by supermarkets to package sushi, fruit and other products. The processor installed collection boxes in supermarkets where customers return the trays. It grinds and hot washes them and processes the PS in a Gneuss MRS extruder.
“I think that tray-to-tray recycling will be the future,” Wefelmeier said.
To prepare for the future, Gneuss sells its MRSjump extruder, which is based on the original MRS design but is designed for closed-loop recycling of PET trays, which, unlike bottles, may be contaminated with other polymers due to coextruded or laminated layers.
“This MRSjump offers even more intensive decontamination and a deeper vacuum of 1 millibar instead of 25 millibars for the standard MRS,” Wefelmeier said.
For more information:
Gneuss Inc., Matthews, N.C., 704-841-7251, www.gneuss.com
Kuhne Anlagenbau North America, London, Ontario, 416-700-7444, https://kuhne-ab.de/en
SML North America Service Inc., Gloucester, Mass., 978-281-0560, www.sml.at
Bruce Geiselman | Senior Staff Reporter
Senior Staff Reporter Bruce Geiselman covers extrusion, blow molding, additive manufacturing, automation and end markets including automotive and packaging. He also writes features, including In Other Words and Problem Solved, for Plastics Machinery & Manufacturing, Plastics Recycling and The Journal of Blow Molding. He has extensive experience in daily and magazine journalism.
