A growing number of companies are switching from urea formaldehyde to polyvinyl acetate (PVA) adhesives in their production facilities. Why? Some reasons include a reduction in veneer peel, reduction of hot press temperature and reduced cycle times. Those who made the switch offer additional reasons.

"I've been trying to switch adhesives for the last five years," says Arthur Verlaan, president of Descor Industries Ltd., of his recent switch from urea formaldehyde to PVA adhesive in his custom furniture manufacturing plant. Descor's workers use PVA adhesives to glue veneer to panels for processing. Verlaan says he made the switch in his Markham, Ontario, production facility because, after five years of reading reports on the subject, being involved in his local government and observing techniques in Europe, he determined it was a wise thing to do.

One of Verlaan's foremost reasons for switching adhesives was concern for his workers' health. "We know urea formaldehyde is not a very friendly product for humans," he says. When Descor was still using urea formaldehyde adhesive, entering the 170,000-square-foot-plant in the morning was unpleasant for Verlaan and his 250 workers. They could feel the urea formaldehyde in their eyes and throats when they entered the building, he says.

Kitco Wood Products of Glen Hope; Pa., also recently made the switch from urea formaldehyde to PVA adhesives to glue dimension panels for tables, doors and pedestals.

Bob Kitco Jr., Kitco's plant foreman, agrees that urea formaldehyde produces an unpleasant odor. But his main reason for making the switch is workability. "With urea formaldehyde, what you mixed up you had to use. It couldn't sit overnight," he says.

PVA adhesives reduce glue spreader maintenance and provide better workability.

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Kitco says the pot life of urea resin is only between three and four hours. "And you can keep PVA for two, three days when it's mixed," he says.

How do urea formaldehyde and PVA differ?

Bill Pidsadny, Franklin International's technical sales consultant for the province of Ontario, says, "Urea formaldehyde is normally a resin and powder catalyst. You mix the two and it's activated by heat in a hot press."

Pidsadny notes that mixing errors can occur when the incorrect ratio of powder to resin is mixed to produce the urea formaldehyde. Use of urea formaldehyde also requires the clean up and maintenance of mixing and metering equipment

"Polyvinyl acetate is a one-part system, and it's a pre-catalyzed product," says Pidsadny. Because the glue comes pre-mixed, the possibility of error in mixing the product is eliminated. The necessity of mixing and metering equipment is also eliminated.

Both adhesives pose a mild health hazard. But PVA, says Pidsadny, "is far less hazardous than urea formaldehyde." Some PVAs contain a small amount of aluminum chloride, which is a hazardous component. Urea formaldehyde contains formaldehyde, which can cause eye and throat irritation for users.

PVA does not produce irritating odors. "With PVA, there's no more smell," says Verlaan. "The people on the press are happier, and I'm sure their health is better."

Historically, manufacturers shied away from using PVA because urea formaldehyde was far less expensive. "Sticker shock has always been such that people don't want to take a look at PVA," says Pidsadny. "They could see price and price only. PVA used to be 50 to 60 percent higher in price."

But the gap has narrowed considerably in recent years. "Now the difference is only about 30 percent," explains Pidsadney.

Descor, a company with annual sales of more than CAN $25 million, spends roughly CAN $85,000 on glue per year. The cost of using PVA is roughly 50 percent more for Descor, says Verlaan. But he says the extra expense involved in using PVA is well worth the cost because it helps him save money in other, not-so-obvious areas. "The difference in cost is absorbed by other things," he says.

According to Verlaan, using PVA for veneer layup saves his workers a lot of time. He says they can start using the machines earlier in the morning because they don't have to mix the glue. They also have shaved 15 minutes off clean-up time. "My glue spreader rubber lasts longer, and it stays in better shape because the cleaning of the machine is much easier," he says. "With urea formaldehyde, you have to scrape hard or spray on some agents to keep the glue off."

Verlaan says the Descor workers would sometimes inadvertently break the machines in their attempts to remove the urea formaldehyde. "Now they take only a putty knife to scrape off excess glue," he says.

With PVA, Verlaan says he's seen a large reduction in bleed-through. "When you're pressing with urea formaldehyde, you can see streaking and bleed," he says. `The color coats, the whitening stains and the glazes are more uniform now because the urea formaldehyde bleed-through went right to the surface and filled all the little cracks. The stuff was like glass," he says.

"PVA is a little more expensive," says Verlaan, "but I've got my clean up time reduced, the health of my people has improved, there is less maintenance involved, it's easier to clean up the machines and the life of my sandpaper has lengthened."

Bob Kitco Jr. says that the extra cost involved in using PVA did not dissuade Kitco Wood Products from making the switch. "PVA is more expensive, but it's easier to work with," he says.

Like Verlaan, Kitco says he also saves money in unanticipated areas. "It's easier on the machines. Clean up time is half. It's much easier on your knife blades, planer and sander," he says.

Are there many changes to the process needed when companies switch from urea formaldehyde to PVA? Kitco says making the switch to PVA made Kitco's gluing process easier. "The Franklin glue we use is a one-part glue and it comes premixed. You just pour it out of the tote and put it right in the pressure tank," he says. Kitco Wood Products currently uses Franklin International's Multibond 2000.

Both Kitco Wood Products and Door tested PVA in their spreaders before making the switch. "Franklin was here with us during the switch," says Kitco. And when the company decided to switch to PVA, "Franklin camped out with us for several days to make sure the switch went well."

Verlaan's switch to PVA was a bit more involved. "I had to readjust my whole glue spreader because urea formaldehyde is forgiving," he says. "But with the PVA, you have to put the right amount of adhesive. If you put too much on it doesn't glue. Or if you don't put enough on, you've got problems too." Verlaan says he decided to buy a brand new spreader to replace an aging one after he switched to PVA.

Verlaan says he had to revamp all of his machinery to better tolerances to make sure that the glue being applied was very even, "and when I press it in my press that the substrates are nice and straight."

Verlaan, who currently uses Franklin International's Multibond 1060, says he's particularly glad that the adhesive mixing process had been eliminated. "The glue mixer was broken all the time because urea formaldehyde is really abrasive. It was like working with sand," he says. "Now I receive the glue in totes, and we just gravity feed it into the glue spreader."

Sometimes a change from tried and true methods, like the change Descor and Kitco Wood products experienced, can elicit some unexpected or unwanted surprises. "The only surprise," says Verlaan, "was that my reject rate at the end of the line after finish greatly decreased." He estimates a 50 percent reduction in rejects due to uneven color out of the paint shop.

"We thought it was the people that were not gluing it right," says Verlaan. "But in fact it was just the urea formaldehyde underneath the product playing tricks on them."