Global plastic packaging producers and the after-use value chain are collaborating to eliminate problematic or unnecessary single-use plastic packaging through redesign, innovation or reuse.
However, to achieve systemic change, brand owners still need to take additional transformational steps when it comes to their packaging brand designs.
While plastics recycling technology has improved over the last decade, one challenging limitation is the variety of colors that are used in plastic packaging. This variation can be addressed in part by separating white and natural plastics, but the remaining materials are composed of various colors that create a gray color once blended and extruded into pellets.
Upgrading the shrink sleeve
Gray recycled plastic pellets might not appeal to brand owners that are keen to maintain their original brand designs. It is interesting that in Japan no colored polyethylene terephthalate (PET) bottles are used because of a universal decision to use only clear PET.
The rest of the world, however, is still hooked on colored PET bottles, which does mean finding another solution if sustainability goals are to be reached. This brings us back to the plastic shrink sleeve.
Shrink sleeves have been around for decades. The first ones appeared in 1960 in Japan, where Fujio Carpentry Shop invented them to provide a new form of tamper-evidence following the change in selling sake in wooden barrels to glass bottles.
Shrink sleeves made a resurgence in the early 2000s, and by 2011, full-body wrap labels accounted for 3 percent of overall container bale weights, an increase from 0.65 percent in 2007. Brand owners embraced the shrink sleeve’s 360-degree design capability only to find serious challenges with recovery and recycling, including difficulty removing the labels, blinding of optical sorting devices and melt and bleed issues.
Today’s new shrink sleeves are vastly improved versions of these earlier counterparts. Now they have double perforations that are easily identified and allow the label to be removed by consumers. The new sleeves also allow for polymer recognition of the bottle during automatic sorting, even if the sleeve is still present on the bottle, and they no longer bleed ink into the washing water.
The upgraded shrink sleeves could go a long way toward increasing recycled content and save on masterbatch costs. They also would preserve the original brand and design identity of the bottle to ensure consumer recall.
All the initial design benefits brand managers enjoyed when they first started using plastic sleeves are still present. Any visible part of the bottle also would communicate to consumers that recycled plastics are being used, which is a positive for brand owners.
Improved recycling processes now enable sorting and recycling with the sleeves in place. This is the case for PET sleeves on PET bottles, though the recognition of PET sleeves on high-density polyethylene bottles might seem more challenging. However, even this scenario presents many possible solutions.
Solutions for shrink sleeves
Some recyclers already use machinery that removes labels and external contaminants so that bare bottles go to the near-infrared optical sorters.
Sorting equipment is now capable of detecting both the sleeve and the underlying polymer if the sleeve is thin, for example 50 microns. This would allow the identification of the combined signal and enable the classification of the bottles into the designated categories for recycling.
Being able to identify the bottle under the sleeve and guide it to the correct recycling stream would offer brand owners the added assurance that their packaging would be properly recycled without relying on consumer input. This is where markers, such as the PRISM (Plastic Packaging Recycling using Intelligent Separation technologies for Materials) fluorescent markers developed by a consortium led by U.K.-based Nextek Ltd. come into play, ensuring sleeved bottles are properly identified during the sorting process.
The process is simple: Fluorescent markers are printed on labels or plastic packaging sleeves, and as packaging is sorted at high speed, the invisible marker is triggered by an ultraviolet (UV) light source that identifies the coded PRISM label, reads the code and air propels it into the appropriate recycling stream.
Maintaining appeal and recyclability
In essence, the resurgence of sleeved bottles might just be a way forward for brand owners to maintain their strong design appeal while upping recyclability.
As manufacturers take more responsibility for the recyclability of their products, gray is set to become the new color of sustainable packaging.
The opportunities for innovation via sleeves and labels are vast and could help brand owners and consumers meet their targets and expectations for recycled content and recyclability. Making it technically possible for all our plastic packaging to be reused or recycled will go a long way toward boosting the plastic recycling sector and establishing a stronger circular economy.