Stretching to be green
Although stretch wrap is lightweight as packaging materials go, it still has a role in packagers’ sustainability initiatives-both from a materials standpoint and vis-à-vis stretch wrap equipment.
On the materials side, sustainability hinges on two strategies, says packaging consultant Sterling Anthony: “Source reduction, or how to use less film in the first place, and recycling whatever film is used at the end of the service life. Of all the [disposal] options, recycling has proven to be the most feasible.”
Source reduction translates into using fewer pounds of stretch wrap to do the same job. Thinner gauge stretch film is one approach to source reduction, and it can provide the added benefit of reduced materials costs for the end user.
“Sustainability is both an economic and an ecological model. In the case of thinner film, these two are tied together. Reduced material use makes sense from an environmental point of view, and it also saves money for the user,” says Michael Hildreth, product/marketing manager at AEP Industries Inc.
AEP has developed a 63-gauge linear low density polyethylene (LLDPE) stretch film to replace 80-gauge film in automatic and semi-automatic stretch wrapping applications. The company also markets a 47-gauge LLDPE film for hand wrapping, “replacing 80-gauge films without sacrificing performance,” Hildreth says.
According to Hildreth, end users can reduce materials use by 21% by switching from 80-gauge to 63-gauge stretch film, without compromising unitizing performance. But because the thinner film is more expensive per pound than what it is replacing, the end user’s cost savings are closer to 10% to 15%.
AEP’s 63-gauge film incorporates polypropylene and metallocene compounds, but like other LLDPE stretch films, it is recyclable. Recycled LLDPE stretch film is typically remanufactured into products such as plastic lumber; LLDPE is the most commonly used polymer for stretch wrap.
Compostable biopolymers, though attractive from a green perspective, are not currently a feasible option for stretch film, for performance reasons.
Equipment does its part
Another approach to source reduction is to increase the film’s pre-stretch percentage. This refers to how much the stretch wrapper can stretch the film before applying it to a load.
In practice, one foot of film can be pre-stretched to a length of two or three feet, and hypothetically, up to four feet. “Over the past few years, more and more of our customers have been requesting higher pre-stretch percentages,” says Steve Fleming, director of sales at Wulftec/M.J. Maillis Group.
Fleming adds, “Two-hundred percent pre-stretch was standard, but now it’s 225%, 250%, up to 300%.” Consequently, it takes “quite a bit less film around the load to secure it during transportation.”
In addition to engineering their equipment for higher pre-stretch, stretch wrapper manufacturers are tackling sustainability with equipment features that focus on energy use, film delivery and film breaks.
Wulftec has engineered a positioning system that enables its stretch wrappers to more accurately deliver film to the load, purportedly reducing film use by four feet of film per pallet. On a fully automatic turntable stretch wrapper, this translates into 60 miles of unstretched film per year, and on a semi-automatic turntable, 10 miles of film.
The company’s stretch wrappers also incorporate variable frequency drives on all motors; therefore, only the power required by the load is exerted, regardless of the motor’s horsepower. The resulting energy savings can help reduce the user’s carbon footprint.
A key focus for stretch wrapper manufacturer Lantech, as it addresses sustainability, is the need to get the wrapped load to its destination undamaged.
“The amount of waste created by improper packaging, including improperly applied stretch wrap-in terms of solid waste, fuel and labor-dwarfs the total consumption of stretch film,” says Pat Lancaster, chairman of Lantech. “The reduction of film is not the issue until you are certain you haven’t generated more sustainability issues, and damage, by using less film.”
To avoid damage to stretch-wrapped loads, it’s essential to “put the film at the right place and at the right force, with optimum force all the time,” Lancaster says. “This really gets important when primary packaging is downgauged,” as when corrugated trays replace shippers and when PET bottles are lightweighted.
Lantech’s No Film Break stretch wrapping technology was developed to minimize product damage, but it also delivers a sustainability advantage. The technology eliminates twisting action on the load, enabling users to apply greater film force and improve load containment while reducing film use by up to 50%.
The technology is a good fit for light loads and display packs because loads are not deformed or destabilized by twisting. Plus there are fewer film breaks, so the user can apply fewer wraps of film.
Most importantly, load damage is significantly and consistently reduced. As Lancaster points out, “reducing damage is the long-term sustainability story.”
Kate Bertrand Connolly, a freelance writer based in the San Francisco Bay area, specializes in packaging, business and technology. Reach her at email@example.com.
FOR MORE INFORMATION
AEP Industries Inc.
The Sterling Anthony Consultancy
Wulftec/M.J. Maillis Group