Its Canvera Polyolefin Dispersions are developed using Bluewave Technology to create an ultra-thin, thermoplastic film coating that can be sprayed on from a waterborne formulation to protect a can and its contents.
Free of epoxy
Jonathan Mason, associate research director, DCM, said the metal packaging industry uses both aluminum and steel cans for beverages and aluminum and tin-plated steel for food but these metal containers have been in use for over 150 years.
“Coating is used for two reasons; to protect the can from its contents and to protect the food and beverages inside from the container - you don’t want aluminum or metal getting inside. So it’s both to protect the can and protect the food/drink,” he said.
“The industry needs to convert away from epoxy and BPA.
“Seven years’ ago Dow started a program looking at alternatives to BPA. We started a research effort looking into epoxy. This is where Canvera came in which is a Polyolefin Dispersion which provides a coating free of epoxy and BPA and all the known materials of concern such as styrene, melamine, epichlorohydrine, phenolic, PVC and Isocyanate, acrylic and polyester.”
Bluewave technology
Mason said the innovation that led to Canvera was a mechanical dispersion process known as Bluewave, where you start with Polyolefin pellets, melt them and extrude them in a twin screw extruder, which produces a high internal phase emulsion (HIPE) which locks in the particle size which is then diluted down into the coating system.
“What you end up with, is this Canvera emulsion, a polyolefin emulsion with small 1 micron sized particles, of polyolefin in water which gives you a waterborne system that formulators can develop into a coating and apply to the metal container.”
The coating has been recognized by a number of awards including; the 2016 ICIS Best Product Innovation Award; 2016 R&D 100 Award in the Mechanical/Materials category, and 2016 R&D 100 Special Recognition Silver Award as a Market Disruptor.
“These industry accolades substantiate this novel technology as an effective, drop-in alternative to incumbent epoxy-based metal can coatings,” added Mason.
He said by leveraging existing infrastructure and application equipment, manufacturers do not need to stop production during conversion and Canvera Dispersions may increase productivity by contributing to lighter coating weights and increased line speeds through controlled spray application.