by Liz White, editor
“Release agents – no-one likes them, everybody uses them.” This was the opening gambit in a recent presentation from Dr Peter Prochnow of Acmos Chemie AG, based in Bremen, Germany.
But Prochnow has a solution to this conundrum, in the form of a newly developed plasma-coating technique for moulds that (almost) eliminates the need for release agents.
It also allows users to make polyurethane parts with a Class A surface finish, as needed for automotive components.
This development is not suitable for all types of polyurethane materials, Prochnow said, noting that it is also most suited to long runs of components.
Pointing out that release agents are extensively used because they are needed to demould components without sticking, Prochnow said: “We consider we have found a solution, with IFAM,” (the Fraunhofer Institute for Manufacturing Technology and Applied Materials Research, IFAM, in Bremen), in a project subsidised by various groups.
The solution lies in using plasma – the phase between a gas and another radical phase, with the material prepared in a closed vacuum plasma reactor (see photo). Acmos can coat moulds in this reactor with the new easy-release coating, in a low-pressure, high-frequency process, at about 50°C.
The method takes the fragments of the reactive gas and applies them to the mould surface. Good bonding to the mould surface is essential, and the mould surface has to be “very, very clean,” with…