By Liz Stevens, writer, UV+EB Technology
RadTech’s RadLaunch Class of 2024 included Nvirovate Materials, Inc., of Monroe, Washington. Nvirovate has developed soybean-oil-based, compostable adhesives that are UV cured. The company’s technology – based on a patent portfolio licensed from Oregon State University – delivers the only bio-based pressure-sensitive adhesives (PSAs) that are CO2 negative and, as a result of being UV cured, require only 15% of the processing energy needed for legacy fossil-fuel-based adhesives.
Nvirovate’s products are comprised of over 93% organic materials and produced with oxygen-tolerant compounding. They are manufactured without solvents or water and can be processed using UV on existing equipment. The company’s PSAs are shelf stable for over one year and – per ASTM 6400 – are compostable in standard waste-disposal facilities with 90% decay in 180 days. UV+EB Technology spoke with James Holbery, Ph.D., CEO of Nvirovate, about the company’s line of new products, NV-4 and NV-20.
The Market
Holbery stated that the market for pressure-sensitive adhesives is calculated at $15 billion globally and $6 billion in the US. These adhesives are a component of packaging, which is undergoing a shift toward sustainability. Sustainable packaging is a sizeable market, projected to be worth $470 billion globally by 2027. 1 Food-packaging labels, affixed by PSA, also are in flux and heading toward sustainability. France, New Zealand and Australia soon will require that all imported fruit must have compostable labels, and Canada is expected to follow suit.
Holbery sees the US adopting this requirement eventually. “We are perhaps not the most progressive country when it comes to recycling and compostability,” he said. “But we catch on when it hits the pocketbook. So, while we may not have specific federal and/or state mandates today in the US, they certainly are being discussed.”
In addition to labels on fruit, packaging for some food in Europe soon will require compostable labels, too. “The European Union is requiring that, in 2025 or 2026, all ready-to-eat food packaging be completely compostable, 2” said Holbery. “There really is no adhesive out there yet for labels on ready-to-eat packaging. The EU includes 27 countries that will be affected by this mandate. For grab-and-go food in the EU, and soon in other global markets, there will be a move to cellulose acetate to replace the olefin plastic cover on containers, and they will move to a compostable adhesive for the label as well.” The packaging world, it seems, is in for some big changes.
Seeing a Need and Making a Change, in Two Parts
“Natural-gas derived acrylic has been used to produce pressure-sensitive adhesives for well over 60 years,” Holbery explained. The technology has changed and become more efficient, but it still uses acrylic chemistry mixed with either a solvent solution or an aqueous solution. After applying the solution to a substrate, the liquid carrier is removed by means of heat in production line ovens. “The major players in the adhesives world have used that methodology – chemical mixtures and thermal drying – for decades to deliver useful products like cellophane tape and packaging,” he said.
Part One: Replacing fossil fuel-derived ingredients
Earlier in his career, Holbery was employed as a staff scientist at the Pacific Northwest National Laboratory in Richland, Washington. At that time, from 2004 to 2009, he explored bio-based chemistries. “I initiated a program funded by the auto industry to use bio-based fiber and bio-based epoxides for secondary structures in automotive parts,” Holbery explained. “During that successful project, I worked with universities and the major Tier 1 auto suppliers and OEMs. It was clear then that we needed to transition to more bio-based materials, and that need still exists because these problems take decades to solve.” One of Holbery’s partners on the project had worked in adhesives at Oregon State University, and the pair were looking at traditional adhesives –acrylic plus chemicals mixed together and then dispensed. “But we looked at what might result if we combined a natural-based vegetable oil with cross-linking agents to produce resins,” he said. “Could this be used to make adhesive?” At the time, Holbery did not pursue the idea. “But I came back to this topic and the bio-based reactive chemistry concept,” he said, “because the problem of sustainability in adhesives for packaging needs to be addressed.”
As Holbery describes it, reactive chemistry is not a process used in the packaging and converting industries. “They are used to combining everything in a pot, mixing it, dispensing and delivering,” he said. “That’s a great way to make money. But if we are to transition to a sustainable platform using soybean oil or other vegetable oil, the chemistry gets a little more difficult. It takes more monitoring to process into a usable adhesive.”
Holbery and his team face the hurdle to upscale from lab beaker-quantity production to full-scale production in the thousands of pounds. But even with a flawless production system designed, challenges remain. “What we are proposing is a paradigm shift in a $20 billion industry. It’s not for the faint of heart.” Holbery knows that until a change to PSAs is mandated or until a sizeable market emerges, companies in the adhesive business are not going to change their entrenched methods of making a product.
Part Two: Replacing thermal cure
If moving from fossil-fuel-derived chemical mixtures to bio-based reactive chemistries is a paradigm shift, the notion of doing away with thermal production ovens and using UV to cure the adhesive is a major disruption.
“The vast majority of pressure-sensitive adhesives, over 90%, are thermally cured,” said Holbery. “Producers use large drying ovens to drive off the water or the solvent, and that leaves a sticky, tacky film on a substrate. A much more efficient way to do that is to use ultraviolet energy. It cures within a matter of milliseconds.”
Eliminating the drying lines does more than just cut the energy used in production; it also can improve the environment in the factory and in general. While PSA drying lines in the US must be equipped with condensers to capture the effluent gas, this is not true elsewhere. “In China, where I was working for Microsoft, there are no emission collectors or condensers on the drying lines. They use the cheapest adhesives made from solvents, and all effluent gas is emitted into the atmosphere. In my seven years there, I saw this in a multitude of plants.”
Building a Better Adhesive
Holbery stated that the main advantages of Nvirovate’s adhesive include its bio-based >90% compostable makeup, which is less expensive than petroleum-derived material; the new adhesive’s performance – matching that of legacy adhesives up to 40° C; and its superior safety, especially vis-a-vis skin sensitivity.
Nvirovate adhesive is carbon net negative. Holbery stated that Nvirovate hot-melt PSA sequesters 0.8 kg CO2/kg produced (uncured), and he cited these comparison figures: Acrylic PSA creates between 6-8 kg CO2/kg (uncured). 3 Cured Nvirovate creates 2.9 kg CO2, while cured acrylic PSA water creates 29.1 kg CO2 and solvent creates 25.1 kg CO2 per kg, respectively. 4
Nvirovate PSAs are oxygen tolerant, reducing manufacturing cost and increasing throughput speed. “Nvirovate does not require compounding in a gas-inert environment,” Holbery explained. ”It is a low-cost production process.”
According to Holbery, large US adhesive coating companies are eyeing the plusses of using UV energy. “They have set up pilot lines that are using UV because they see a transition to UV on the way,” said Holbery. “But it is going to take time for production to be scaled to handle six- to ten-foot-wide webs, which is how the large producers set up master rolls. To do business in a market with that kind of competition, Nvirovate will have to compete on price. But at scale, if our calculations are right, we are going to be very competitive.”
The Future
“We are not the first people to think of UV-cured adhesive; far from it,” said Holbery. “But we are trying to use the technology in a way that is forward thinking in that it is sustainable. We are a unique offering in the community; we are bringing bio-based materials and UV technology together to displace what always has been a fossil-fuel-based product line.”
“For us to scale,” Holbery explained, “we have to work within the existing supply chain. We need partners in production, we need to cultivate more customers and we need equipment suppliers and the UV community to partner with us to increase our market penetration.”
References
- “Sustainable Packaging Market to Reach USD $470 Billion by 2027.” Source: Market Research Future, June 25, 2021. https://www.globenewswire.com/en/news-release/2021/06/25/2253076/0/en/Sustainable-Packaging-Market-to-reach-USD-470-3-billion-by-2027-Report-by-Market-Research-Future-MRFR.html
- O’Keeffe, Hazel, “EU Proposal for a Regulation on Packaging and Packaging Waste – the Highlights.” Packaging Law. October 2, 2023. https://www.packaginglaw.com/special-focus/eu-proposal-regulation-packaging-and-packaging-waste-highlights
- Golden, R., “Sustainability Advantages of Ultraviolet and Electron Beam Curing,” July/August 2008, Radtech Report. https://radtech.org/archive/images/sustainability_pdfs/SustainabilityAdvantagesofUVEB.pdf
- Bradlee, C., Wall, C., Sanborn, T., Horwitz, R. (BASF) “UV-Cured PSA – Lower Total Cost of Ownership and Env. Superiority,” RadTech Technical Proceedings, 2006. Fig. 5A – Solvent/Water Dispersion vs. UV Hotmelt = 14X.
