The high-barrier PET bottle is something of a Grail among technology developers. Various ways have been tried to obtain it, coinjection, spray coating and plasma treatment among them.
SIPA’s chosen route is Smartcoat, a “dip and spin” technology that involves immersing blown bottles up to their necks in special liquids, removing the excess by centrifuging them, and then curing the coating in infrared and ultraviolet radiation. The process is done twice: once to apply a coating with a barrier to oxygen and carbon dioxide, and once to apply a coating that provides mechanical and chemical protection.
Process technology is ready
The coating process is state of the art, and SIPA believes it has important advantages over rivals. Smartcoat has been conceived as a modular coating production line with an output varying from 12,000 to 42,000 containers per hour. The process was developed in collaboration academia and other industrial partners.
The main limitation in the way of commercial success is the sensitivity to moisture of the barrier coating in very hot and humid conditions, which until now has been one of the key challenges to overcome for a more global acceptance by customers. SIPA is now working hard to get the chemistry right.
Bottles are fully recyclable
“The big advantage of the Smartcoat technology is that the barrier coating is applied onto the external surface of the bottle, which means no contact between the coating material and the liquid in the bottle,” says SIPA Innovation Director Laurent Sigler. “Moreover, the properties of the barrier material do not affect the full recyclability of the PET bottles, which means that they can be integrated into the “normal” bottle-to-bottle recycling stream.
Aim is to increase resistance to humidity and heat
“The main objective of our current development program is to develop solutions to improve the barrier resistance of the barrier material in environments with very high moisture levels, up to 80%, and at high temperatures. It’s a hard nut to crack, we know this, but we are sure we are on the right track.
“We are confident we will soon be able to deliver a robust and sound solution that stand up to such environments. Then, Smartcoat will be the most convenient technology available on the market today. It will be the only technology on the market that can combine a fully recyclable packaging together with an economically viable barrier solution.”
Total system will be optimized
Sigler says his team is aiming to develop a barrier coating with a new chemical formulation with much higher resistance to humidity and heat than previous offerings. “We will then optimize the top coat formulation as well, to improve adhesion between the two layers. The performance of our overall barrier solution is going to be significantly improved!”