May/June 2002
Whatever the language—English (wax), Spanish (cEra), or French (cire)—
wax continues to spell trouble for recyclers of corrugated containers.
While there are many proposed solutions, none has solved the problem—yet.
By Lynn R. Novelli
When the waxed corrugated container was introduced, food shippers hailed it as the answer to their packaging needs. That’s because the paraffin-coated container proved to be an effective moisture protector, enabling meat, fruit, and vegetables—which had to be packaged in ice or moist conditions—to arrive fresh at their destination.
Today, these sturdy and moisture-proof containers are still used in mass quantities. Of the 26 million tons of corrugated produced in the United States in 2001, about 3 to 5 percent—or 780,000 to 1.3 million tons—was waxed corrugated, according to the Fibre Box Association (Rolling Meadows, Ill.).
While waxed containers are great at preserving perishable products, they have a serious flaw: They’re virtually unrecyclable. The same properties that make waxed corrugated a useful, moisture-proof product also make it a recycling headache for scrap processors, brokers, and paper mills alike.
“Waxed corrugated is my worst nightmare,” states Jim Maher of Morgan Price & Co. Inc., a Miami-based scrap paper broker. In South Florida, he notes, where importing and exporting fresh produce is big business, “you can buy carloads of waxed OCC, but nobody wants it. It all goes to the landfill.”
Echoing Maher, John Gold of The Newark Group’s recycled fibers division (Marblehead, Mass.) says, “Our experience with wax is never good. There’s nothing good to be said about it on the recycling end.”
Currently, most waxed OCC—or WCC—is landfilled. This not only creates what one environmental group calls “a huge waste problem,” but it also represents a sizable loss of secondary fiber—fiber that could, if recycled, add several percentage points to the current OCC recycling rate of about 75 percent.
Fortunately, many parties—from waxed-corrugated producers to chemical firms to entrepreneurs—have been hard at work seeking solutions to the WCC problem.
What’s the Problem?
Why is WCC considered such a material non grata? Here are just some of the reasons:
• For grocery stores, retailers, and other generators of WCC, the material imposes an extra labor burden because their employees must devote time to sorting waxed from unwaxed OCC. Since the sorting process is far from perfect, a reported 10 to 15 percent of discarded containers are unwaxed OCC, which means lost recycling revenue for the generator as well as lost secondary fiber. The discarded containers also add to the generator’s waste-disposal costs. In addition, if WCC makes it into the generator’s OCC bales, it could cause the bales to be downgraded by the scrap buyer or broker.
• For scrap paper packers, WCC requires more personnel for sorting, which increases labor costs, takes time, and slows throughput—all of which means higher production costs.
“We aren’t supposed to have waxed corrugated in the bales that go to the mills, so we have to run everything through a sorting line before it gets to the baler,” says Ben Harvey of E.L. Harvey & Sons Inc., a paper processor in Westborough, Mass. “Pulling out the waxed corrugated requires sorting by hand, and that’s a very difficult thing to do.”
Midland Davis Corp. (Moline, Ill.), a scrap metal and paper recycler, considered replacing its manual paper-sorting operations with an automated sorting system, says Marty Davis, president. The company ultimately rejected the equipment idea because the system couldn’t cull many common paper contaminants, including wood and WCC. “So,” says Davis, “we have two people on the line whose full-time job is to sort waxed OCC—and they’re busier than I’d like them to be.”
For paper packers, WCC also increases their disposal costs and—perhaps most importantly—is the leading cause of OCC rejections by paper mills. Typically, when a mill inspector finds waxed corrugated in even a single bale of OCC in a load, he or she will reject the entire shipment—a “costly penalty,” Harvey says.
• For paper mills, WCC is generally considered a prohibitive material because of its negative effects on their machinery and finished products. Wax, for instance, can delay the defibering process in a mill’s hydrapulper, which can reduce the strength of the final product. Wax can also prevent good interfiber bonding and clog the wires and felt in a mill’s machinery.
“When the wax carton goes into the beater, it’s in cool water. The wax comes off the carton, but it gets gobbed up,” says Ray Petermeyer, West Coast associate for Moore & Associates, an Atlanta-based paper recycling consulting firm. Older, less-automated equipment that used hotter water could absorb wax with fewer problems than the newer, high-tech equipment, notes John Ockenfels of paper processor City Carton Co. Inc. (Iowa City, Iowa). While the latest pulping equipment can tolerate small amounts of wax without breaking down, the clumps of wax that form in the process still affect the final product, Petermeyer explains.
According to John Gold, as little as 1 pound of wax in a bale of OCC can linger in a mill’s equipment, causing spots and holes in the corrugated coming off the line for the next 35 to 40 minutes. Wax can also make the surface of the finished product undesirably slippery, which can lead to processing and handling problems and prevent laminates and adhesives from sticking.
Keeping the Stream Clean
If any mill knows the challenges of WCC, it’s Cedar River Paper Co. (Cedar Rapids, Iowa), a Weyerhaeuser subsidiary that makes medium and linerboard. As the largest single-location consumer of OCC in the United States, “waxed OCC issues affect us more than anyone,” says Ed Sparks, mill support supervisor. “Our concern is to keep wax out of the system because it creates a slippage issue with new boxes. When wax gets into the linerboard and medium, the finished product is not usable at the box plant.”
At Cedar River’s mill, bales of OCC enter the plant and are fed directly into the pulping system. If a significant amount of waxed OCC is in the feedstock and gets recycled into new product, a quality inspector will cull the rolls. “The defective product has to get cut up, then we rebleed it into the system and hope it’s diluted enough not to cause problems,” Sparks says.
To keep waxed OCC out of its papermaking process, Cedar River conducts random quality checks of the 3,000 tons of OCC it consumes daily. Material is classified as good, outthrows (contaminants that won’t affect the end product), and prohibitives (contaminants that will affect the quality of the finished product). The mill grades material based on the ReMA (11) specification for corrugated containers, which dictates that prohibitive materials may not exceed 1 percent of a load and that total outthrows (including the prohibitives) may not exceed 5 percent. Cedar River has found that wax accounts for about 87 percent of all prohibitives in its purchased scrap, while plastic and other materials account for the remaining 13 percent.
When the standards and practices committee of ISRI’s Paper Stock Industries Chapter reviewed the corrugated specifications last year, the members considered changing the tolerances for wax. In the end, the committee decided not to change the specs, instead opting to “leave the responsibility for deciding what’s acceptable to the mill and the packer,” says Ockenfels, who chaired the committee. “The goal for the packer has to be to meet the specifications the buyer wants. The mills have what they have as far as equipment, so it has to be on an individual basis, and it’s up to the packers to know their customers.” As Gold adds, “Every mill has the right to set its own standards for what it’s buying.”
To meet those standards, most packers say the best approach is to nip the WCC problem at its source by encouraging generators to discard the containers and, thus, prevent them from ever entering the recycling stream. To achieve that goal, packers have to educate OCC generators about the problem and how to identify waxed containers. Packers must also train their own plant employees about the importance of removing waxed material from the OCC mix. “We also work with the mills,” Harvey says, “to minimize the impact of waxed corrugated and help them understand how difficult it is to keep the material out.”
From the paper-mill side, Sparks says that he likewise spends “a lot of time working with OCC suppliers to identify and keep the waxed bales out of our system. We try to have our OCC sources train their box handlers or baler operator to not put the waxed in with the unwaxed OCC.”
Such education and training efforts must be ongoing to keep pace with the rapid employee turnover at OCC generators and packers. “It becomes a constant education,” Harvey explains. “We try to get back to our suppliers with stickers, posters, and education programs to help them learn to identify waxed OCC.”
To help OCC generators and recyclers identify waxed corrugated containers, the American Forest & Paper Association (Washington, D.C.) and the Fibre Box Association developed voluntary packaging standards in 1998. The standards encouraged box manufacturers to label their waxed cartons with the word “wax” in English (wax), Spanish (cera), and French (cire).
Beyond Landfilling
Given WCC’s recycling problems, OCC generators, paper packers, and mills have had little choice but to dispose of it. This habit is becoming less attractive economically and environmentally, however, due to increasing tipping fees and decreasing landfill space.
Meanwhile, waxed-corrugated producers, box manufacturers, their trade groups, and others have invested much time and money exploring options for WCC.
Getting the Wax Out. Several firms, for instance, have developed techniques to remove wax from corrugated containers.
In 1998, Inland Paperboard and Packaging Inc. (Indianapolis) and Kadant Black Clawson Inc., a Middletown, Ohio, pulp and paper equipment manufacturer, introduced Xtrax, a patented wax-removal process that creates a suspension of wax in water, followed by separation of the usable fibers through reverse screening. The wax/water solution passes through the screen, leaving behind the fiber, which is fed into the production line. The wax/water is then separated, with the recovered wax being sold for reprocessing and reuse on new corrugated containers.
While the Xtrax system works fine, there have been no takers thus far, says a Kadant Black Clawson spokesperson. When the process was developed, the price difference between pulp and paper was sufficient to motivate some corrugated producers to pursue technologies for recycling waxed OCC. Since then, market conditions have changed to the point where the Xtrax process “is not worth it economically right now,” the spokesperson says.
Another company—Hercules Inc., a Jacksonville, Fla., chemical company serving the pulp and paper industry—created a chemical treatment that separates wax from corrugated during pulping. In the system, waxed OCC is processed in the pulper at 120 degrees F for 30 minutes. A proprietary chemical treatment is added that causes the wax particles to separate from the paper and clump together into large, rigid particles. The pulp slurry is then screened to remove the agglomerated wax, yielding clean, wax-free pulp.
Though Hercules introduced the process in 1999, a company spokesperson couldn’t confirm that any mills are currently using it.
Other Containers and Coatings. Container and wax manufacturers have focused other R&D efforts on creating alternative coatings and containers.
The landfill-space crisis in Europe has already prompted the European Union to ban the use of wax on corrugated, forcing manufacturers to develop new forms of protective packaging. Though the situation isn’t as critical in the United States, it’s time for an alternative to wax, says Morgan Price’s Jim Maher. “Waxed corrugated is a dying industry,” he says. “Wax coating is a very expensive process, and the new technology is toward better coatings.”
Indeed, The International Group Inc. (Wayne, Pa.), a worldwide manufacturer of petroleum-based waxes, is researching different formulations to make the wax easier to separate from the paper fibers. The firm is also exploring lighter-weight waxes that would be easier to treat or disperse in the pulping process.
The challenge is to create new coatings or containers that have the same performance characteristics as today’s waxed containers without their recycling problems. The American Plastics Council (Arlington, Va.), for one, is exploring reusable plastic packaging for perishable foods, while several box manufacturers have proposed plastic liners.
The Newark Group has already developed polylined corrugated cartons for the food industry. Though these cartons protect the product and hold up well, the polylining does present some recycling challenges, says Gold. “Some mills can handle it, some can’t. When it’s done correctly, polylining can be a good solution.”
Several years ago, Weyerhaeuser came up with a recyclable packaging system for fresh produce that combines special package features, packing processes, and cooling methods. The patented ClimaPack system creates a modified environment inside the box, without ice, that retains moisture, holds color, resists mold and odor, and maintains product freshness. Since the shipping cartons are plain, dry corrugated, they can be recycled along with other OCC.
Fuel, Compost, and Beyond. Other approaches to the WCC problem have centered on alternative uses for the material, such as processing it into fuel pellets or artificial firelogs. In the 1990s, International Paper Co. installed systems at several of its plants that shredded waxed corrugated, processed it into dense pellets, and mixed it with wood chips to create a cheap, efficient fuel for its boilers.
In contrast, SP Newsprint Co.’s mill in Newberg, Ore., has considered using WCC as fuel at times but has never found it to be economically feasible. “You have to remember that waxed OCC is competing with other fuel sources,” says John Lucini, a scrap paper buyer for the mill. “By the time the material is pelletized so it can be burned in our system, it’s too expensive to produce or use.”
Composting is another alternative use for WCC. In 1998, the Paper and Paperboard Economic Council teamed with The International Group to commission a study to explore that idea. Researchers at McGill University in Montréal found that waxed corrugated will decompose over several months when mixed with other organics, with the resulting compost usable to grow nursery stock. While some Canadian nurseries are pursuing this approach, composting waxed OCC isn’t considered a viable, long-term solution for the huge volume of WCC generated in the United States.
In the end, the ultimate solution to the waxed-corrugated problem remains elusive. Until that solution is found, paper recyclers resign themselves to managing the best they can. “Waxed corrugated is a problem, but we’re taking many different approaches to solve it,” says Harvey, “and I don’t stay awake at night worrying about it.”
Lynn R. Novelli is a writer based in Russell, Ohio.•