A novel technology expands polymers to increase their yield and results in reduced cost and weight in plastic packaging applications, claims its US developer.
MicroGREEN Polymers, which manufacturers sustainable plastics, said its patented solid-state microcellular plastics process, showcased at Pack Expo in Chicago this week, reduces the amount of plastic used in an application by creating microscopic bubbles in common thermoplastics.
The company said that this increases the material’s volume without compromising performance, and the process significantly increases output while lowering material cost by 75 per cent.
“Our converter and manufacturing partners are always looking for opportunities to make more plastic products from less source material, and in today’s economy, it’s becoming imperative due to the rising cost of petroleum affecting production costs,” said Tom Malone, CEO of the Washington-based company.
The company claims that the finished plastics, containing microcells, retain the look and feel of solid plastics due to the creation of an integral skin over the cellular core structure: “You get the beneficial properties of layered materials without the added steps of lamination or co-extrusion.”
Thermoforming throughput and cycle times are comparable to those of solid plastic counterparts, continued the company.
It added that the solid-state technology can be applied to a broad range of polymers including recycled polyethylene terephthalate (rPET) and the emerging bioplastics such as Natureworks polylactic acid (PLA), with the resulting plastics suitable for use in food and protective packaging applications.
Meanwhile, the WHEYLAYER project, informed by the fact that whey acts as a good moisture-barrier film, is focusing on developing a whey protein coated film for use with plastics films in food packaging.
Whey is a by-product of cheese production, and according to TTZ, 50 million tonnes of it are yearly accumulated in the EU.
Dr Hauke Hilz, team manager with TTZ’s Department of Bio Processing Engineering Food Technology explained that although polyolefin films such as polyethylene (PE) and polypropylene (PP) are excellent moisture barriers, they must be laminated with synthetic polymers like ethylene vinyl alcohol (EVOH) and polyvinylidene chloride (PVDC) copolymers to provide an oxygen barrier.
“The resulting polymeric structures, while effective in minimising the permeation of oxygen, water vapour, and odour, are characterised by their poor reuse due to difficulties in separating each layer for its individual recycling,” said Hilz.
He said that whey coating on plastic films has advantages over the synthetic polymers in that it can be easily removed, chemically or enzymatically, for recycling of the plastic.
“This project will build on past research in order to arrive at a commercially feasible technique for developing whey coated plastic films, without compromising the oxygen or moisture barrier performance of conventional plastic films, while also increasing their recyclability,” added Hilz.