Unwelcome wax: the presence of waxed corrugated boxes continues to muddy the paper recycling stream

Recycling Today, Oct, 2003 by Dan Sandoval

Many paper and paperboard mills are extending the types of recovered fiber they can take in, and as they do so, quality issues can crop up. One of the most difficult materials to handle is wax-coated or wax-impregnated corrugated containers.

While there are some end markets for the material, it is almost universally unwelcome for re-pulping. Many paper companies are using the material as a source for boiler fuel or, in some cases, using the waxed corrugated as a compostable material.

The problem stems from wax's unsuitability as a material in the making of new paperboard products. Wax, because of its nature as a separator, does not intermingle with the water used to make pulp.

Several companies have taken steps in an attempt to address this issue. The results of experiments, though, have not yet been determined.

THE NUMBERS. Wax-coated corrugated containers are not the most dominant part of the recycling stream. However, because they often can be easily commingled with non-coated streams of old corrugated containers (OCC), the problems with finding and keeping the material out of the pulping stream are significant.

According to several industry sources, about 5 percent of the corrugated produced in the country ends up with some type of wax or other coating. The waxed boxes often end up going into the produce industry, especially grocery stores. However, even at a 5 percent level, this volume is significant.

Kadant Black Clawson, Fulton, N.Y., is one company that has spent a significant amount of time and effort to develop a process to make waxed corrugated a viable material in the paper recycling stream. The company has introduced a system that uses a combination of washers to extract significant amount of wax from the corrugated.

Users of this system have so far been limited. According to Doug Crow, the technical services application manager for Kadant Black Clawson, "The basic problem with wax impregnated board is that it is slippery, it can get on the machine and can effect the slide angles. You have a find a way to get rid of the wax.

"Black Clawson has come up with a product that aims to do that. With this washing system, a company runs between two and three washers in a series, forming a counter current washing system," Crow explains.

While the system greatly reduces the amount of wax on the cardboard, one of the biggest drivers for a company considering whether or not to pay the additional cost of using this system is the price spread between wax corrugated and conventional old corrugated. "You need a bigger price break to make this system viable," Crow adds.

While mills and recyclers deal with what to do with the waxed corrugated that is prevalent in the waste stream, the ultimate decision is made by the box buyers. Grocery stores, a major end market for waxed corrugated boxes, may be forced to throw away as much as 15 percent of their OCC because of wax contamination. But a number of grocery stores say their use of waxed corrugated is in response to consumer demands.

To replace these boxes, some companies are offering other, more effective ways to coat the boxes. However, these coatings may cost more, something that grocery stores find difficult to pass on to customers.

As things stand now, recyclers typically take in wax corrugated for free (as part of the overall shipment) or a charge is imposed on it.

UPGRADING. While many people look at the waxed boxes as a contaminant, or a less valuable fiber material, Crow notes that the goal of new systems is to have the waxed OCC be considered a better quality material than conventional OCC.

The waxed coating, after all, protects the core fiber from contaminants that cheapen the value of the OCC. In this way, some consider the waxed OCC similar to aseptic containers: Expensive to strip away the coating, but holding high quality fiber.

One paper company that has been testing the use of waxed corrugated in its pulping systems has been Domtar's Cornwall, Ontario, Canada paper mill. The company has been using OCC to make some of its fine papers. According to John Mullinder, the company has been blending a small amount of wax corrugated in with its regular OCC.

While the markets for wax-impregnated OCC have been limited so far, there have been some steps taken to address the situation. The Corrugated Packaging Alliance (CPA), Rolling Meadows, Ill., commissioned a study on the issue of waxed boxes. Hal Tanner, the consultant on the project, said the study looked at four different issues with wax boxes:

1. The quantity of the wax treated boxes;

2. What percentage of the wax boxes were claimed to be re-pulpable;

3. Developing a database of replacements;

4. A list of coated roll producers.

The results of the study are not yet available, although Tanner says that the CPA hopes to have the report completed this month.

Although wax coated cardboard boxes only make up between 3 to 5 percent of the total OCC stream, Mullinder says that as much as 20 percent of the OCC generated in the produce industry is made up of wax-coated boxes.