Streamlining the process

The growing demand for products with recycled content is causing some original equipment manufacturers and processors who already make these items to reevaluate their processes to find the sweet spot between material supply, available technology, manufacturing efficiency and customer satisfaction.

D&W Fine Pack, a Wood Dale, Illinois-based manufacturer of food packaging and foodservice disposables that already processes polyethylene terephthalate (PET) sheet with up to 100-percent-recycled resin, in January commissioned a new line at its Fort Wayne, Indiana, plant that uses technology from Gneuss Kunststofftechnik GmbH that eliminates the need to buy and process recycled pellets. Instead, D&W Fine Pack will be able to buy recycled postconsumer PET flake.

The Gneuss MRS extruder also eliminates the need to crystalize and dry flake before it is extruded. That means the line will use an estimated 29 percent less energy than D&W Fine Pack’s other 30 extrusion lines and allow the use of lesser grades of recycled material.

“One of the beauties of this technology is it gives our procurement people the ability to go out and buy on the fringes a little bit more than what some of the other technologies allow,” says Russ Stephens, vice president of engineering at D&W Fine Pack. “Not only did we invest in this MRS technology, but we invested in a pretty sophisticated material receiving, handling and blending system.

“Now we can blend A-level, B-level and C-level postconsumer flake together to get us to the most economically viable cost point,” he adds. “Some of that material may not have been able to go into packaging in the past because it was not clean enough or was too blue or the intrinsic viscosity was too low. Now, at least in our case, we have the material handling and extrusion technology to be able to blend it appropriately for whatever the particular application might be.”

The new material handling system was designed in-house using parts from various suppliers. The new line is the first PET line in the Fort Wayne plant. Resin previously has been delivered by truck and rail, and now the plant handles resin delivered in super sacks or boxes.

D&W Fine Pack has been purchasing PCR pellets for about 10 years as well as postindustrial flake.

Stephens declined to give the amount of the total investment except to say it is a multimillion-dollar transaction. He also declined to reveal the size of the extruder or throughput, but in a news release, D&W Fine Pack described it as the largest of its kind in the U.S.

Multi-Rotation System (MRS) technology was unveiled in the U.S. at the 2009 NPE show. It is based on a conventional single-screw extruder but is equipped with a multiple-screw section for optimal devolatilization.

The polymer melt is delivered into a large single-screw drum. The drum contains eight small extruder barrels parallel to the main screw axis. Installed in these small extruder barrels are the eight screws, which are driven by a ring gear in the main barrel to rotate in the opposite direction to the main screw while they rotate around the screw axis.

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Gneuss says the surface area of the steel parts in contact with the melt is exchanged at a rate of more than 25 times greater than with a co-rotating twin screw extruder. Because of the opposite rotation direction and high speed of the satellite screws, the polymer surface area is increased by a factor of 100 compared with a single-screw extruder and a factor of 40 compared with a twin-screw extruder.

Gneuss builds MRS extruders in several sizes ranging from 35mm to 200mm with throughputs ranging from 80 pounds per hour to 4,500 pounds per hour.

The new line at D&W Fine Pack’s Fort Wayne facility uses a Gneuss extruder and melt filtration system. Other parts of the line are from Pawcatuck, Connecticut-based Davis-Standard, which supplied most of the seven other extrusion lines in the plant, including the controls and interface, which gives the new line a familiar look for operators.

All the PET sheet D&W produces is used internally for its wide range of food packaging. However, Stephens thinks the new line eventually will enable the company to sell recycled-content sheet to others.

There is a possibility that the new line could be duplicated in other D&W Fine Pack plants. “I hope so, but I think we will wait and see how it performs,” Stephens says. “We expect this is going to be wildly successful. We have done our due diligence.

“A big part of that is around the economics of PET and the supply of postconsumer flake,” he adds. “The availability of postconsumer flake is going to have a large impact on how fast we can duplicate this technology or invest in a different technology that can get us to a similar place. We are very bullish on this, but we are not married to it.”

Stephens says D&W Fine Pack tries to buy postconsumer and postindustrial material domestically but will look offshore when necessary.

Another benefit of the Gneuss MRS technology, Stephens says, is that it can process polypropylene, polystyrene or other packaging materials in addition to PET. “When we invest in this technology, we want to invest in something that is flexible just in case pressures in the marketplace change and we need to shift without making another major investment,” he adds.

The company has about 30 extrusion lines using traditional extruders with crystallizer dryers. “There are other options we can do there to kind of enable the postconsumer flake,” Stephens says. “It may not be the MRS technology, but certainly there are others that we can consider as well.”

The author is editor of Plastics Machinery & Manufacturing and can be contacted at rshinn@endeavorb2b.com.