Did you know about this amazing creature? The Blue Mussel.
This mussels lives on the wave-battered shores of the Oregon coast. This mollusk uses small adhesive threads to attach to rocky surfaces in tidal zones, resisting the erosive forces of water and waves. The mussel’s tenacious grip has inspired new wood glue technology called PureBond® that is nontoxic and sustainable, leading the way for innovation in the wood products industry.
They feed on bacteria, plankton, and detritus filtered from ocean water. A colonial species, they cling in large groups to rocks and each other using strong adhesive threads, called byssal threads. Despite living on wave-swept coastlines, mussels are able to hold on tightly using an underwater ‘glue.’ This ability has caught the attention of scientists and entrepreneurs.
Traditionally, man-made glues perform poorly on surfaces that are wet, rough, or dirty, and the blue mussel’s ability to overcome these common obstacles helped it gain attention from the wood products industry.
The Innovator
Dr. Kaichang Li
“I was amazed at the time to see these small mussels attach themselves so strongly to rocks… I didn’t know of any other adhesive that could work this well in water and withstand so much force.”
MOTIVATION
Dr. Li, a wood science researcher, understood the serious health and environmental issues linked to traditional wood adhesives like UF and PF resins. These glues release formaldehyde—a toxic gas associated with irritation and even cancer—during manufacturing and use. In fact, over half of all formaldehyde produced globally goes into wood adhesives.
Because these resins are also fossil fuel–based and non-renewable, the wood industry faces pressure to find safer, more sustainable alternatives for the future.
Of the more than 1.78 million metric tons of adhesive resin solids consumed by the wood products industry in North America in 1998, over 90% were formaldehyde-based.
PROCESS
Dr. Li drew on existing research about how mussels adhere to wet, irregular surfaces. Studies had identified a key amino acid in mussel adhesive proteins called DOPA, known for its strong bonding ability due to a chemical structure called a catechol group. These catechols create powerful bonds even on wet surfaces—something most synthetic adhesives struggle with. While others had explored DOPA for various uses, Dr. Li was the first to test its potential in wood adhesives, and his lab results confirmed its effectiveness.
Dr. Li demonstrated that marine adhesive proteins had the right bonding properties for a formaldehyde-free wood adhesive, but their high cost and limited availability made them commercially unfeasible. Turning to his background in wood science, he explored soy protein—an abundant, renewable resource that is about 40% protein and had historically been used in wood adhesives before being replaced by UF and PF resins.
Recognizing the complementary features between soy and mussel proteins, Dr. Li chemically modified soy protein by attaching DOPA-like catechol groups, mimicking the strong adhesive chemistry found in mussels. This enhanced the strength and water resistance of the soy adhesive, making it comparable to formaldehyde-based resins. Encouraged by the results, he began seeking industrial partners to commercialize the innovation.
Product Development: DESIGN
Dr. Li continued refining the soy protein to better mimic mussel adhesive proteins. He experimented with adding catechol-like structures and other functional groups to replicate the role of DOPA. However, chemical modification at scale wasn’t practical for mass production.
To solve this, he developed a curing agent called Kymene, which modifies the soy protein during the heating phase of plywood manufacturing. Kymene blocks certain amino acids in soy that aren’t found in mussel proteins, making the soy behave more like natural marine adhesives. In production, soy protein is applied to wood fibers, then Kymene is added; when heated, they cross-link to form a strong, durable bond.
Once the adhesive chemistry was optimized, Li and his team conducted mill trials and scale-up tests, leading to the development of PureBond® technology.
TESTING
To test wood composites for water-resistance, variations of cyclic boiling and drying tests are performed. For example, for exterior-use wood composites, standard procedure is to boil a wood sample in water for 4 hours, dry it, and boil it again. If it doesn’t degrade, it’s considered highly water-resistant. Lab testing demonstrated that composites created with adhesive technology using modified soy protein are comparable in both water resistance and shear strength to traditional phenol- and urea-formaldehyde resins. The cross-links created in PureBond panels are so strong that they can be boiled for hours without degrading.
Why PureBond® stands out
Unlike other soy-based or alternative adhesives, PureBond® offers the perfect balance of sustainability, performance, and affordability. It’s:
- Formaldehyde-free and safe for indoor air quality
- Cost-competitive with traditional toxic resins
- Strong and durable, with an attractive, lighter glue line
- Faster to cure and more energy-efficient in production
- Safer to handle, reducing health risks during manufacturing
By switching entirely to this bio-based adhesive, Columbia Forest Products eliminated over 47 million pounds of harmful resins and reduced toxic air emissions at their facilities by up to 90%.
It’s a smarter adhesive—better for people, better for the planet.
THE PUREBOND TIMELINE:
2000 Dr. Kaichang Li is inspired by mussels on the Oregon coast
2003 Steve Pung of Columbia Forest Products meets Dr. Li; CFP agrees to fund R&D efforts
2005 PureBond announced to the public and production begins
2006 CFP converts all 7 of its plywood plants to PureBond technology
2007 Dr. Li, CFP, and Hercules, Inc. receive Presidential Green Chemistry Challenge Award
2008 CFP announces production of 25 millionth hardwood plywood panel using PureBond technology
2010 Over 40 million PureBond panels have been manufactured and sold
