OSU's new wood glue has muscle inspired by mussels

The nontoxic adhesive, developed by an assistant prof, is transforming how products such as plywood are made
Monday, May 09, 2005
MICHAEL MILSTEIN
The Oregonian

CORVALLIS -- A weekend trip to the Oregon coast gave Kaichang Li an idea that is revolutionizing the wood manufacturing industry and will mean cleaner air indoors and out.

It's a new adhesive that's a safe replacement for chemical glues in plywood, particleboard and other manufactured wood that leak noxious formaldehyde fumes into homes. It's so simple and inexpensive that Li, an assistant professor at Oregon State University's College of Forestry, can whip it up from soy flour in a kitchen mixer on his laboratory counter.

The tenacious foothold of mussels in the ocean surf inspired the new glue, and its commercial potential could extend to almost every new home and building. OSU patented the adhesive in the United States and other countries, and is licensing it to companies.

Columbia Forest Products of Portland, the nation's largest producer of decorative plywood, has exclusive rights to use it in plywood. The company announced last week that it would completely switch to the soy-based adhesive within a year, eliminating formaldehyde in its plywood panels.

"You always think there's not a new mousetrap out there, but this one has really shaken the industry," said Brad Thompson, who oversees plywood manufacturing at the company.

The industry in the U.S. and Canada spends about $2 billion a year on adhesives, and more and more wood products are manufactured by pressing and gluing together layers or small pieces of wood. The products are generally inexpensive and can be made with smaller trees grown on plantations instead of larger, older trees seen as valuable to wildlife.

The phone in Li's Corvallis office has been ringing nonstop with calls from companies that want to know more.

"That's probably another one," he says, as it rings again.

The idea for the revolutionary adhesive hit him about five years ago during a weekend crabbing trip to Newport. He and his friends caught no crabs, so they gathered mussels instead. Li saw that the rugged shellfish use a natural adhesive to secure themselves to rocks and wood pilings amid buffeting ocean waves.

A good adhesive must be strong, of course, but also flexible enough that it doesn't break like an eggshell under stress. Mussels evolved the ideal solution. They secure themselves with a network of tiny but tough silken threads known as a byssus that absorbs the force of waves without snapping.

It's made of protein chemically tied to particular amino acids that make it sticky and strong.

Li marveled at the mussel's glue especially because it's not weakened by water. That's important for adhesives in plywood and other wood products because industry standards require that they stand up to hours in boiling water during testing.

"Thinking about it, I didn't know of any other type of adhesive that could work this well in water and withstand so much force," he said.

Inspiration from tofu

The question was whether he could reproduce the mussel's glue so it could be used commercially. A lunch of tofu made Li think about the soybeans that went into his meal. They contain lots of protein, just like the byssus of a mussel.

He and his research group in the Wood Sciences and Engineering Department realized they could duplicate the mussel's adhesive by blending soy flour with the amino acids that give the shellfish its astonishing grip. Columbia Forest Products helped fund the research.

Li's group found other natural ingredients -- such as the tannin that gives tree bark its brown color -- they could use to mix up the same sort of adhesives, and published their results in scientific journals.

The soy blend offered an ideal solution, though. Soy flour is inexpensive, plentiful and widely produced by U.S. farmers. It carries none of the health hazards of formaldehyde glues.

The trouble with formaldehyde

Paneling and particleboard made with the chemical glues release formaldehyde vapor, which can collect in confined spaces and cause bronchitis, irritation of the lungs and eyes, dizziness and headaches. New homes full of such pressed-wood products may contain three times the formaldehyde levels known to cause health problems, according to the U.S. Environmental Protection Agency.

Formaldehyde also poses problems for wood manufacturing plants, which must protect workers from fumes and are under pressure to reduce the amount vented into the air.

Federal figures show that Oregon plants, mainly those making wood products, poured 944,276 pounds of formaldehyde into the air in 2002, the last year with figures available. They may soon be forced to install expensive new emissions controls.

But eliminating the formaldehyde by switching to the soy-based adhesive might prove a simpler and cheaper option, industry officials say. Cost is critical in the wood business; until now, making products with formaldehyde-free glues drove prices up 20 percent to 30 percent.

"This is really the first cost-competitive option," Thompson said.

Stronger than the wood

It's also tougher. During testing to measure its strength, the wood in plywood panels breaks apart before the glued seam where the adhesive holds the wood together, Li said.

In a pot on a hot plate in his laboratory, Li boils samples of plywood and hardboard -- another kind of pressed-wood panel -- made with the soy-based adhesive. Chunks boiled for as long as two days look almost as good as new, while those made with the chemical glue have turned spongy and weak.

The adhesive penetrates the wood fiber and locks it in place, Li said.

"It's like you put a key in a lock and turn it," he said. "You can't get it out."

The discovery could have a huge payoff for the university. Oregon State will not disclose its earnings from Li's new adhesive but said the money could mean a big jump in overall income from licensing of all inventions, which totaled $1.5 million in fiscal 2003.

"The potential is there to make that number go up a pretty significant amount," said Brian Wall, a licensing associate in OSU's technology transfer office.

Michael Milstein: 503-294-7689; michaelmilstein@news.oregonian.com


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