TECHNOLOGY | FOAMS
The die makes all the difference
Aside from polymer and foaming agents, the extrusion die is also a core component for the production of foamed boards, sheets and tubes, according to equipment maker KraussMaffei Berstorff. “It ensures defined discharge of the melt containing the blowing agent, subsequent foaming and final shaping in the calibration system,” the company says. As such it requires in-depth technical design expertise. While slot dies are used for foam boards, blown film dies
are frequently applied for film and sheet. These dies are equipped with slitters to cut the tubular sheet to a flat sheet suitable for winding. Twin or four die heads are generally used for expanded tube production as the simultaneous extrusion of two or four
foam tubes substantially enhances cost-effectiveness. All extrusion dies are equipped with an oil-based temperature control system for several zones to achieve the exact temperature profile required for foam products. �
www.kraussmaffeiberstorff.com
A four-die head for expanded tube production manufactured by KraussMaffei Berstorff Image: KraussMaffei Berstorff
phosphate chemistry.” This is said to make them suitable for food-contact and medical applications. The Budit F Series provides endothermic foaming ingredients for chemical foaming process- es for extrusion and injection moulding. In physical foaming processes, at low concentrations, the cell nucleation can be precisely controlled, says Wassmer. Controlled cell formation can be achieved, thanks to what is said to be unique kinetic reaction profiles, which lead to fewer sink marks and surfaces with improved aesthetics. Budenheim offers solutions for all types of foam-
able polymers, including silicones as well as polyolefins and engineering plastics. Clariant said last year it was seeing strong
interest in its Hydrocerol endothermic chemical foaming masterbatches, particularly in the Chinese automotive market where manufacturers have been preparing for tough new fuel efficiency and emission standards. It claims that part mass reductions of between 5-20% are possible in PP, PA and TPO without sacrificing performance or compromising appearance. BMW has exceeded that with a 25% weight saving on a dashboard carrier, the company says. Using the Hydrocerol masterbatch can also deliver process savings, according to Clariant. The endothermic foaming reaction absorbs heat from the polymer, allowing cycle times to be shortened and productivity to be increased by up to 20%. Sinking and warpage is also reduced.
CLICK ON THE LINKS FOR MORE INFORMATION: �
www.sabic.com �
www.borealisgroup.com �
www.lyondellbasell.com �
www.reedychemicalfoam.com �
www.pochem.co.jp/english/jpp/ (Japan Polypropylene)
Typical application and processing temperatures for Budenheim’s Budit F series of endothermic foaming agents Source: Chemische Fabrik Budenheim
60 COMPOUNDING WORLD | January 2019
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www.crayvalley.com �
www.braskem.com.br �
www.polyfilcorp.com �
www.budenheim.com �
www.clariant.com
www.compoundingworld.com
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