Rough, absorbent, porous and penetrable—some deem obvious challenges associated with manufacturing paper-based protective, sustainable and recyclable packaging “insurmountable”; others do not.
Three visionary members of the latter group: BOBST, UPM Specialty Papers and Michelman, partnered in the development of a mono-material, high-barrier, paper-based structure, coated with functional layers that can be accommodated in existing recycling streams. And, in the process of bringing their brain trust—oneBARRIER FibreCycle—to life, they established methodologies to cast obstacles aside.
- Full scale collaborative efforts began in 2020
- Initial launch occurred in June 2022
- Twelve months later, the sustainable and recyclable packaging, with paper as its foundation, has captured considerable attention among brand owners and packaging converters worldwide
At interpack 2023, FLEXO seized the opportunity to sit down with a team of executives—one from each of the three partners—to explore the development and acceptance of what many have come to view as a game changing development.
Partners’ Perspectives
“Recycling is a must for any new packaging solution coming to the market. We can be proud of having accomplished that with an elegant, lightweight solution that is ready for commercial use,” explained Sara Alexander, marketing and communications manager, flexible packaging at BOBST. She continued, “People are looking for alternatives to replace polypropylene (PPL) and other plastics. Developing such solutions requires an ecosystem of key players hailing from the machinery, paper and chemical worlds.”
Photos courtesy of BOBST
Janne Varvemaa, director, products & techno UPM Specialty Papers, added, “Together we managed to create a world-leading barrier solution that offers brand owners a packaging solution that is not only sustainable, but also delivers on functionality.” Elaborating on the significance of the team’s accomplishment, he stated, “oneBARRIER FibreCycle represents the kind of packaging the world needs right now, enabling brand owners to reduce their reliance on fossil-based or non-recyclable materials, increase their use of renewable materials, and meet their sustainability targets.”
Thierry Van Migem, sales director, EMEA, Michelman, declared, “By incorporating the highly versatile barrier properties provided by advanced coating technologies, we have been able to meet the performance needs and sustainability goals that are prevalent in the market.” He further noted, “Working together and not in silos, we were able to identify issues and adjust rapidly, promoting agility and improving speed to market.”
“Just as a famous Greek philosopher said, ‘The whole is greater than the sum of its parts.’ By uniting our respective expertise, total performance of this oneBARRIER FibreCycle packaging solution exceeds what we could have achieved separately,” he concluded.
Motivational Forces
Speaking to what transpired and why, the three partners indicated that the market thirsts for new solutions and structures that provide the right barrier performance and drive a transition from multi-material, non-recyclable packaging to alternatives that are recyclable in existing recycling streams. They emphasized the point that today’s operating climate demands a fully reliable process to consistently produce top quality paper-based recycle-ready ultra-high or high barrier packaging—with faster time-to-market.
Steps successfully navigated entailed:
- Understanding the paper substrate and its inherent characteristics
- Selecting the right chemistry and optimum coat weight for each functional coating step
- Identifying correct coating methods
- Determining the necessary drying profile
- Executing careful web handling requirements stemming from paper’s brittle nature
Moisture Management
Alexander stressed what she called, “the particularity of each element,” and noted, “Thinner and thinner substrates are specified.” In response, she reported, “We increased the percent fiber in each package to make it more recyclable, then moved on and addressed the need for barrier sealability—exasperating a challenge on paper.”
She insisted, “Paper is a delicate area. Moisture management of machinery is fundamental to high-performance metallization. Pinhole-free coating is essential to the process as it allows vacuum metallization applications that let the barrier stay intact.”
She acknowledged that BOBST’s technologies, specifically, vacuum coating and wet coating; as well as its test facilities, proved critical in development.
Fit & Functionality
Varvemaa observed, “Paper, globally is one of the most recycled materials. However, recyclability is not enough, we must consider responsibility all the way from sustainable forest management to operations which guarantee food safety.”
He commented, “UPM Solide Lucent, a recyclable specialty kraft paper is especially well-suited as a base paper for further converting. It works well with all printing methods, including rotogravure. UPM Solide Lucent is globally available as UPM Specialty Papers’ distribution channels cover all continents. Flexo printability is quite good.”
Varvemaa also said, “The paper’s smoothness, density and strength make it an excellent foundation for achieving optimum barrier properties, so a major focus of the co-creation project was developing the coating layers. It’s a long process, but functionality to protect the food inside is where it all starts as barrier values and performance must meet the requirements of long shelf-life food packaging.”
Fulfilling that functionality requires that the packaging meets the necessary water vapor and oxygen transmission rates, according to Varvemaa. “The challenge is finding the right combinations, right recipes and right chemistry for the surface properties, layer thicknesses and folding abilities, as well as securing product safety and getting feedback from shelf-life testing., but through this co-creation we discovered some new benefits.”
Performance & Printability
Van Migem maintained, “The paper, being very smooth, very dense and very strong, enabled a lightweight and uniform coating. The paper and the primer have a symbiotic relationship to guarantee a high-barrier performance and its high density and folding performance secure functionality in the packaging value chain.”
He revealed, “The majority of other solutions on the market are low-to-medium barrier. We have achieved high barrier targets with oxygen and water vapor values below 1 and we are now moving toward ultra-high barrier systems with target values for both oxygen and water vapor below 0.1.” He deemed oneBARRIER FibreCycle “an alternative to non-recyclable metallized PET-PE laminates.”
Details provided by Michelman emphasized that the coating system is built around a multi-functional coating with excellent adhesion to the paper. The single base coating provides oxygen, moisture, and mineral oil barriers, while aiding the metallization process. Michelman has developed a range of heat seal coatings, optimized for different seal initiation temperatures (SITs) and further enhancing moisture barrier properties, taking into account coefficient of friction (CoF) requirements for different packing lines.
These heat seal coatings are applied on top of the metallization to protect the metal and ensure a tight seal on the package. To complete the system, an overprint varnish (OPV) with additional moisture barrier properties is applied over the print, bringing the overall performance into the required range for high barrier food packaging with an extended shelf life.
Van Migem specified the target of this development was to achieve oxygen and moisture vapor barrier values < 1 and stressed that the primer was designed for oxygen barrier, flexibility and high affinity with the subsequent metal vacuum deposition. Addressing the rheology of the coating system, he noted, “Heat seal on top of metallization allows for a tight closure of the packaging even in the triple point.” Other stats gathered indicted that after priming, the package is 99 percent recyclable and after printing and heat seal it has a 94-95 percent recyclability rating. The structures are tested and certified by PTS, an external industry standards body.”
Converting Concerns
Putting the substrate and coating system together successfully hinged on BOBST’s expertise in equipment design, application know-how, and optimization of the converting process, necessary to obtain the smooth, pinhole-free surface required for subsequent vacuum metallization, according to Alexander.
She reported that, over the past four years, BOBST has carried out intensive paper coating tests, conducting more than 550 tests on paper (from 32 gsm to 100 gsm) and testing various chemistries and optimized coating weight for both the primer and top coating.
For the record, BOBST explained that the oneBARRIER equipment package comprises the EXPERT K5 vacuum metallizer and the oneBARRIER EXPERT COATER or the one BARRIER MASTER COATER coating lines, depending on the converter’s productivity needs. oneBARRIER solutions web widths range from 1300 to 2900 mm.
The EXPERT K5 vacuum metallizer is said to deliver:
- Perfectly accurate web handling
- High cooling capacity with largest diameter coating drum in the industry at 700 mm
- Largest coating window in the industry with improved collection efficiency of 16 percent
oneBARRIER COATER coating lines are claimed to deliver:
- Excellent coating profile consistency with water-based and solvent-based coatings
- Single or multiple coating heads as option
- Modular trolley-type configuration allowing for future changes of application technology
- Hybrid dual technology dryer or full floatation dryer with option for additional tunnel sections
Transformative Approach
Varvemaa sought to wrap things up and stated, “This structure has proved to be a powerful innovation, resulting in a transformative approach to safeguarding food products. This is a truly ground-breaking solution for foods with a long shelf-life. These products are usually packaged in a variety of plastic laminates or plastic structures that are not easily recyclable. Our aim was to produce a recyclable, paper-based packaging solution–and we can say ‘mission accomplished!’”
Van Migem, for his part, concluded, “Solving complex sustainable challenges often arises from the relentless wave of new legislation and market disruptions.” His overall assessment, like his partners: “Sustainable paper consumers are happy to go greener!”