Recycling compatibility was a lively discussion amongst high-level brand owner, converter and supplier attendees at AWA’s shrink sleeve conference, writes Danielle Jerschefske
AWA hosted over two hundred attendees, including a number of big-name brand marketers, at its International Sleeve Label Conference and Exhibition in Cincinnati earlier this year. Corey Reardon, president of AWA, said, ‘The sleeve label market is growing, is dynamic and an opportunity for growth in package decoration. Still we are seeing some challenges with recycling materials as are all packaging sectors.’
Brands enjoy the 360 degree decoration capability of shrink sleeve labels, the vibrant colors and design for contour that the technology offers, which is why environmental issues need to be addressed immediately. Shrink sleeve decoration achieved six and a half percent growth globally in 2011 and five percent growth in North America and Europe.
According AWA’s 2012 shrink sleeve report, global brands are specifying alternative materials to replace PVC for sustainability and recycling reasons. There has been some development around PLA, but tests have found the material difficult to convert and difficult to handle in the recycling stream. There is a rapidly rising concern in Europe and North America surrounding shrink decoration materials for labeling PET containers, with good reason.
Most and least recyclable materials
On March 1 NAPCOR, a trade organization for the North American PET plastics industry, released this position statement: ‘Containers with full-body wrap labels as a percent of bale weight has increased from 0.65 percent in 2007 to three percent in 2011. The association says the key challenges with cradle-to-cradle recovery for shrink labels are: the blinding of auto sort devices; difficulties removing labels; melt and bleed with regard to adhesives and inks.'
The Association of Postconsumer Plastic Recyclers (APR) published its statement on March 9 finding ‘all sleeve labels to be unsatisfactory’ with regard to viable recycling in current infrastructures. The only label to pass satisfactorily was a polypropylene wrap label that does not shrink. Both associations are looking to the value chain to innovate so that more plastic materials can be re-processed and sustainable design is used in the development process.
It is clear that the issue of shrink sleeve label recyclability has reached a critical point. According to Dave Cornell, technical director at APR, who represents 20 PET recyclers in the US, ‘The label resin must be compatible with the bottle side wall or it needs to be separable. Clarity of PET resin is what sells. When you print on a label it can carry over to the resin and tarnish clarity.’
Adhesives were said to scorch, burn and cinder in the PET recycling process that reaches 270 degrees C, creating yellowing specs and haze. He continued, ‘If you can avoid the adhesive it is a good thing.’
Shrink design for recycling
The two main ideas tossed around at the conference to overcome recycling stream compatibility issues for shrink sleeve labels:
• Shrink labels designed with a perforation that allows consumers to remove the label prior to disposing of the container into recycling outlets
• Floatable materials that easily separate and remain buoyant in the wash-out process.
The problem with the first proposal is whether consumers can be enticed to remove the labels and how quickly the industry can adjust to making changes to perforate labels for removal while maintaining performance.
Within the SPCs’ labeling for recovery project, committees are working on floatable label performance. The hang-up with this notion is the ability of recycling conveyer sensors to tell the difference between shrink-wrapped bottles and wet-glue or PS labeled containers. They only read ‘PET’ or ‘no PET’.
Other questions include whether a floatable design would impact the PP and polyethylene cap recovery stream. Would de-labeling equipment be required? If the labels can be effectively removed, is shrink a better decoration choice when it comes to environmental impact? What about the ability to recycle the label material? Would that require air or water elutriation (a process for separating lighter particles from heavier ones using a vertically-directed stream of gas or liquid)?
APR shares tips
Cornell confirmed that wraparound PP labels separate very nicely in the PET recovery stream and explained that the near Infrared NIR auto-sorting machine cannot see through an opaque label. ‘The sensor is unable to penetrate through the label, so defaults to 'not PET' and the container is kicked out.
Cornell suggests designing labels with transparent panels to give the auto sorting machines a chance, yet such designs impact the marketing goals of brands selecting shrink sleeve decoration.
He said, ‘The density needs to be well below 1.0 (.995 or less) in order for material and polyester to separate (Plasticsrecycling.org). None of the currently used materials are good – OPS, PETG, PVC, PLA all sink.’ Stretch sleeves made of LDPE had also not performed well in early tests.
PET sinks and PP floats. If the label sinks, then the label color mixes with PET. So there is an opportunity to develop an effective shrink material with a surface layer of PET that allows sufficient identification in the conveyer systems and still floats.
There are two issues when it comes to shrink label substrates and PET flake contamination. Firstly sleeve labels are relatively thick and PET bottles are about half as thick as they were five years ago. This would require improved elutriation.
The second problem with regard to PET flake contamination and a perforated zipper design relying on mechanical separation is that such automated technology is proprietary to PET recyclers, so not every recycler has such integrated systems.
Cornell suggested, ‘We need competitive polyolefin labels. Polyolefin floatables are a revenue stream. Recyclers are survivors and they have to have something to work with. Demand is twice the supply.’
Sustainable shrink innovation
CCL introduced a new LDPE material, TripleS, that is a stretch sleeve that offers design and application benefits and a few environmental perks. Mike Fairley covered this introduction in detail on page 21 in Labels & Labeling issue 3. MRI Flexible Packaging too discussed its LDPE-based stretch sleeve development, C-Fit.
Both C-Fit and TripleS are claimed to reduce material and costs by around one third. An additional benefit is that the stretch technology requires less energy, on average 5.75 kwh versus 85.5 kwh, to apply the label to a container. Stretch sleeves require no glue or solvents; they should create no ink bleed and hold a specific density less than 1.0 so it becomes buoyant in the pre wash process.
Karlville’s Raul Matos encouraged the use of promotional labels in coordination with a perforated shrink label design to help educate consumers. Global brand owners such as SC Johnson, heavily involved in the SPC, must also be informed. Matos also called for the establishment of label converting guidelines for electro-optical scanners.
Eastman Chemical shared its progress on developing awareness around the environment and shrink sleeve decoration in an effort to avoid the pressures that NAPCOR and APR are applying.
Tri-City Beverage and Eastman Chemical collaborated with 16 Virginia Tech industrial design and graphic arts students on a six-week project to develop Eastman Embrace copolyester shrink film label concepts for Dr Enuf, a long-standing beverage brand on the East Coast, with the aim of enticing consumers to remove the label and recycle the container. The project refreshed an old brand and makes sustainability fun.
As brands look to embrace shrink sleeves to increase sales and reap the other benefits of the decoration technology, the labels must be designed to empower and educate consumers and must allow recyclers to viably close the recycling loop. Cornell was sure to tell attendees that APR is not out to stifle innovation, but that solutions must be found that can benefit everyone in the supply chain.
This article was published in L&L issue 4, 2012