Crown Caps with DYNAPOL®
When you're thirsty, all you want is to down that drink fast, without giving a thought to what exactly it is that keeps the contents inside the bottle: the crown cap. The DYNAPOL® polyesters produced by the Adhesive Resins & Colorants Business Line are major components of the coatings on cans and seals. Refrigerators too, which keep beverages at a refreshing temperature, have a coating that contains DYNAPOL®.
This coating is applied in a coil-coating process. "If they are to be used in food packaging, they must be odorless and tasteless and have no adverse effects on human health,” says Rainer Spittka of Polyesters Technical Service. He also points to a further advantage of this product group: the excellent balance between hardness and flexibility.
In the final production step the tinplate is coated with a formulation containing DYNAPOL®. Only then is the plate printed with the brand name decor, which might be the well-known logo of a soft drink. A DYNAPOL®-based clear coating is then applied for protection from mechanical damage. Before the crown caps can seal the bottles hygienically and tightly, they must be punched out from the tinplate and provided with a seal.
"The packaging market's always changing,” says Spittka. "Our customers want an attractive design and, at the same time, a safe, eco-friendly, and innocuous product.” For this reason, our products too must continually be adapted for changing market requirements. In addition to the classical coatings for cans, tubes, and caps, DYNAPOL® is increasingly being used for flexible packaging systems, too. Moreover, air conditioners, window blind slats, and heat-reflecting exterior wall elements receive a DYNAPOL®-containing finish by means of the coil-coating process.