PLA Film Shrinks to Fit

7/27/2019 PLA Film Shrinks to Fit

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PLA Film Shrinks To FitDemonstrating excellent printability and machinability characteristics, sustainable compostable polylactide fi lm is now being converted by Seal-It for use in shrink-sleeveapplications.BY ANNE MARIE MOHAN

New York-based label converter Seal-It is on the "husk," as it were, of an exciting new advancement in the shrinkfi lm label market. Since February 2006, Seal-It has been

offering its customers shrink-sleeve labels made from a fi lm based on renewable resources that has proven to be competitive in both characteristics and cost with most

traditional, petroleumbasedfi lms.

The transverse-direction-oriented (TDO) polymer, called EarthFirst PLA TDO, is made from a corn-based polylactide resin, NatureWorks PLA, engineered by NatureWorks LLC.

The result of considerable research and development by fi lm manufacturer Plastic Suppliers, EarthFirst PLA TDO is the fi rst commercially-viable shrink fi lm made from

NatureWorks PLA to enter the market.

"I really believe that this is the fi lm of the future," says Seal-It president Sharon Lobel. "While we shouldn't disregard the other fi lms because they all have their place depending

upon the application, PLA is the new kid on the block now, and everybody wants to get to market with it fi rst."

Background

NatureWorks PLA was fi rst introduced in 2000 and, since then, it has slowly but steadily spread across consumer packaged goods applications, from thermoformed deli

containers and fi lm lidding to disposable tableware and beverage bottles, and from Europe to the US. The technology used to produce the resin involves harvesting the starch

stored in natural plant sugars. This sugar is then fermented into lactic acid, which is used to create a clear plastic, or PLA, that can be used for a variety of packaging formats.



Initially, one of the barriers to adoption of PLA was its high price relative to existing, petroleum-based fi lms. In 2002, NatureWorks LLC, then Cargill Dow, christened its fi rst

large-scale production facility in Nebraska, for the manufacture of PLA, with an estimated output of about 136 billion kilograms of resin per year - half of which was slated for

packaging applications (NatureWorks LLC's Ingeo fi bers for textiles are also made from PLA). This increased production capacity, coupled with a petroleum market besieged by

volatile pricing, helped to bring the cost down to a more palatable level forpotential customers.

Says Rich Eichfeld, vice president of Business Development, Plastic Suppliers: "We fi rst manufactured PLA fi lm on May 5, 2004. We had considered using it prior to that, but it

was too costly. Once NatureWorks LLC's manufacturing methods gained economies ofscale, it became more feasible for us."

these applications has been the rigidity of the fi lm. "One-hundred percent PLA has limitations," he explains. "It's a very brittle product.The way we addressed this problem was

through different additivesand manufacturing processes."

It took Plastic Suppliers about one year to engineer a PLA fi lm suitable for shrink-sleeve label use. To develop the fi lm, Eichfeld says the company drew upon its expertise in the

manufacture of its Polyfl ex TMOPS preferentially-oriented PS shrink fi lm, as well as on input from co-branding partners like Seal-It. "Through communication, we were able to

make proper adjustments to the fi lm to meet Seal-It's concerns," he says. "Then we would allow them to look at the fi lm and give us their feedback, and we kept refi ning as we

went along. Seal-It was instrumental in helping us to introduce this product tothe market."

Seal-It

Operating two, side-by-side facilities totaling 13935 square meters of combined manufacturing space, Seal-It has provided label printing and converting services for 20 years.

With a focus on heat-shrinkable label applications, the company works with a variety of substrates, including polyvinyl chloride, polyethylene terephthalate glycol and OPS to

produce full-body shrink-sleeve labels, tamper-evidentneckbands, multipack wrappers and more.

The company's services include in-house design and prepress, as well as modifi ed fl exo printing, gravure printing and label seaming. Seal-It's newest equipment is a one-meter,

10-color gravure press from a proprietary supplier.

Upon Plastic Suppliers' invitation, Seal-It tested the EarthFirst PLA TDO fi lm on its converting equipment during the material's development phase. "We've been fortunate that

we've been able to work with the fi lm and learn how to handle it on our equipment," says Lobel. "Some other converters may just be starting now; it will take them a while to learn



how it handles. Even though the fi nal product looks pretty much the same [as labels made with petroleum-based fi lms], the converting and handling of the fi lm is very different.

Ittakes time to learn how to work with PLA."

Characteristics

EarthFirst PLA TDO, available in 2- and 2.4-millimeter thicknesses, is scuff-resistant, compliant to FDA standards and offers up to a 75- percent shrink in the transverse direction.

According to Lobel, only PETG has a higher shrink rate - at 80 percent. "But the seventy-fi ve percent of shrink that PLA offers will accommodate 99.9 percent ofthe applications

that are out there," she adds.

For shrink-sleeve applications, Eichfeld relates that PLA's inherent brittleness is somewhat of an asset, allowing it to shrink easily onto a package. However, because it has a

lower heat tolerance than other label fi lms, users need to program their shrink tunnels to run cooler than usual.

As for printability, EarthFirst PLA TDO is said to be compatible with all traditional printing processes, as long as converters learn how to adjust their tension controls to

accommodate the new material. As Lobel explains, part of Seal-It's learning curve with the new fi lm was to test it on every piece of equipment necessary to produce a shrink-fi lm

label. "We took it every step of the way," she says. "We had to look at the printability to make sure that the colors were vivid and bright. We looked at our slitting equipment and

said, 'If this is how we slit fi lms that we already work with, how do we have to change the process to accommodate PLA? Do we need different blades? Do we need different

equipment?' We looked at the seaming process to see if there were any differences there, and so on."

Market conditions

As for the issue of cost, PLA is now gaining a favorable footing because of the stability of maize prices versus petroleum-based polymers such as PET. In late 2005,

NatureWorks LLC reported that its PLA product had been price-competitive for the previous 16 months with PET, andin some cases, it was even cost-advantaged over PET.

Says Eichfeld: "It's not the least-expensive product on the market; that would be PVC. But PLA can compete with most shrink fi lms." Concurs Lobel: "The cost for PLA is better

now than it used to be. It's still more than PVC, but after [Hurricane] Katrina, even the cost of PVC has gone up. If you rate the cost of the four fi lms - PVC, PLA, PETG and OPS

- I'd put PLA somewhere in the middle."

Machinability and cost considerations aside, PLA's desirability also lies in its natural, renewable origins. In January, with the purchase of Renewable Energy Certifi cates (RECs),

NatureWorks PLA became the fi rst and only greenhouse-gas-neutral polymer on the market. The RECs serve as an offset to cover all of the emissions from the energy used for

the production of NatureWorks PLA - from the fuel farmers use in their tractors to the fi nal production of the polymer. NatureWorks PLA also uses 60- to 70-percent less fossil

fuel resources than traditional plastics, reports NatureWorks LLC.

Another benefi t of the resin is that products made from NatureWorks PLA can be disposed of through composting.

While Seal-It cannot yet disclose any of its customers pioneering the use of shrink-fi lm labels made from EarthFirst PLA TDO, Lobel says that "everybody wants to do it fi rst,"

especially the larger customers. Eichfeld agrees, noting that in the last three months, the increase in interest in the product has been "dramatic."

"The interest level has increased one-hundred-fold," he says, attributing it to Wal-Mart's launch late last year of a sustainable packaging initiative that included a goal of

converting an estimated 114 million PET containers to NatureWorks PLA.

Lobel says that while stores such as Wal-Mart have given PLA a big push, that was not the driver behind Seal-It's adoption of the material. She relates that "it's exciting to offer a

fi lm that has no dependency on oil and is totally home-grown."



Green packaging primer

Applications: Biodgradable/compostable plastics made from renewable resources are now being used in virtually every packaging application. Among them, windowed bakery

bags; confectionery wraps; disposable cutlery, plates and bowls; grocery and produce bags; deli containers and trays; cold drink cups; beverage bottles; pallet wrap; shrink-film

labels;pressure-sensitive materials; fi lm lidding; and others.

Biomaterials cornucopia: Ingredients for today's green packaging include corn, potatoes, sugar, tapioca, palm-oil byproducts and wood pulp, among others.

1. Terminology

Biodegradable: Capable of decomposing rapidly by microorganisms under natural conditions (aerobic and/or anaerobic). Compostable: Recycled through the composting of organic solid waste. Composting is the means by which organic matter isrecycled in its environment.

Sustainable: Among the characteristics cited by the Sustainable Packaging Coalition are that it is benefi cial, safe and healthy for individuals and communities throughout its life

cycle; is sourced, manufactured, transported and recycled using renewable energy; and maximizes the use of renewable or recycled source materials.

Drivers: The growing popularity of biopolymers for packaging is being driven by several factors, including the skyrocketing cost of petroleum - food packagers were hit in 2005

with price hikes for conventional plastics between 30 and 80 percent; the marketing potential for natural foods in natural packages for increasingly health-conscious consumers;

recent initiatives by major retailers, such as Wal-Mart, to increase their use of sustainable packaging; and the increased production capacities of bioplastics suppliers.

2. International standards

• ASTM D6400 Standard Specifi cation for Compostable Plastics, in the US.

• ASTM D6868 Standard Specifi cation for Biodegradable Plastics Used as Coatings on Paper and Other Compostable Substrates, in the US.

• EN 13432:2000 Requirements for packaging recoverable through composting and biodegradation, in Europe.

3. Resources

The Biodegradable Products Institute, www.bpiworld.com

European Bioplastics, www.european-bioplastics.org

The Sustainable Packaging Coalition, www.sustainablepackaging.org

PLA Film Shrinks to Fit

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