The skin packaging (pictured) is based on DuPont Surlyn, a highly transparent polymer designed to protect susceptible, three-dimensional component surfaces. The product is the result of joint development work between DuPont, machinery producer Zappe Verpackungsmaschinen and film producer Jura-Plast.
Miele is using the technology at its plant in Warendorf, Germany, to prevent high-gloss, thermoplastic bezels for washing machines from becoming scratched as they make their way through the fully automated assembly line to retail and, ultimately, to the end-user’s home. The tailored skin packaging process helps prevent rejects and the corresponding raw-material waste, Miele says.
The skin-film itself, and its production residue, can be recycled in the polyethylene waste stream.? Surlyn weighs about one third less than polyethylene, which was the material used in an early development stage, DuPont and Jura-Plast say.
The film also offers good heat absorption that makes it stretchable after only 10 seconds of heating, compared to about 15 seconds required for polyethylene, when working with Zappe’s SKVA-5050 3D skin-packaging machine, the company says. This saves process energy and helps achieve short cycle times.
Zappe managing director Ulrich Zappe said Surlyn’s chemical structure makes it melt-stable and tough even when heated, a particularly important quality for three-dimensional components, because it enables high draw ratios without the risk of the film tearing at the edges.
The formulation of its base layer also ensures that no air bubbles form between the film and the component surface, improving appearance, according to Jura-Plast managing director Jürgen Müller. The use of a modified resin makes component-film adhesion high enough for a fully assembled 5 kg washing machine door to be transported using vacuum grippers. At the same time, the consumer can easily peel off the film and leave no residue behind, Müller said.