Coating and Converting 2013

Derichs GmbH celebrates its 40th anniversary

That is the motto of our Krefeld-based roller manufacturer. The company, founded more than four decades ago, is constantly making a name for itself with its trailblazing innovations, and now provides an extremely wide range of products, covering smoothing, embossing, laminating and cooling and heating rollers. Derichs rollers are employed in the widest possible variety of applications and tasks: They distribute molten plastic produced in the extruder and shape it into films and panels, smooth it out within a pre-defined thickness tolerance, giving it a matt or gloss surface laterally or longitudinally or embosses patterns on it. Aside from producing monofilms and panels, the rollers can be used go produce multi-layered laminates of different plastics and plastic coatings on substrates made of paper, textiles and aluminium. Plastics such as PE, PP, PS, ABS, PET, PC and PMMA are used in these processes.

"This multiplicity is a constant challenge to us, though it requires not only excellent specialist knowledge of the chemical and physical behaviour, the processing qualities and product applications of plastics, but also expert knowledge of plant and machine technologies", explains Eberhard Derichs, the company founder and namesake in an interview with C2. "On top of this, it should be remembered that rollers being used in finishing systems and calenders have to satisfy very demanding mechanical and thermal requirements," continues Derichs. "The molten plastic generates very strong wedging forces in the spaces between rollers, which induces linear forces of between 2000 and 3000 N/cm, depending on the film or panels, which increase as the gap between rollers reduces. As rollers have to work under these forces, they are subject to very large and dynamically changing bending loads". Due to the various different melting and solidification points of partially crystalline or amorphous plastics, the rollers must follow the processing sequence as closely as possible thermally in order to achieve the required product quality. Depending on their position within the processing plant, rollers will have to either warm or cool the product in production. The various of tasks in this area ranges from homogenising temperatures  from the material's melting point in the calender all the way to shock cooling of molten plastic as it is being looped through a chill roll unit. The latest of Derichs' innovation is our new generation of type DSWT- 08 smoothing rollers, which can handle linear loads of between 2000 and 3500 N/cm.

"These smoothing rollers are capable of convecting temperatures very precisely to the whole barrel length and provide up to 30% higher energy performance as compared to conventional rollers" stresses Derichs. "With our rollers it is possible to produce extremely thin films and so to achieve the target end temperature directly."

The young team centred around Stephanie Holzmann, shown here chatting to Eberhard Derichs, are ideally equipped to look forward into the future. "The mix of generations, each with its own strengths, allows us to respond flexibly, quickly and with increasing knowledge to the relevant market situation."

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