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REPRINTED FROM EUROPEAN PLASTICS NEWS - October 1999
Dumaplast develops microcellular profilesMuCellmicrocellular foam technology is now being used commercially for the first time in Europe. Dumaplast, a Belgian extrusion company, is using the US technology in the full-scale production of PVC extrusion profiles for interior applications, hollow wall claddings and ceilings. The company claims that it has achieved significant material savings using the samePVC material composition as it used in its existing products. The MuCell microcellular foam process, from the Massachusetts-based Trexel, uses supercritical fluids of atmospheric gases, rather than chemical blowing agents, to create evenly distributed and uniformly sized microscopic cells throughout thermoplastic polymers (see EPN, July/August 1997, page 21). The microscopic cell size and even distribution permit the foaming of thin profiles, while maintaining product appearance and key properties. The Belgium company began development work with Trexel about a year ago. Because the Dumaplast profiles are thin and use interior ribbing for strength and rigidity, the foaming process had to be capable of producing a carefully balanced flow to maintain dimensional uniformity and product functionality. Trexel modified Dumaplast's existing extrusion equipment to accommodate the MuCell process. During the product development cycle, Trexel and Dumaplast designed new dies to provide the correct amount of foaming and to balance the flow of the material. The development process was challenging because the process conditions, die configuration, and downstream treatment conditions had to be optimized. However, Dumaplast was ultimately able to implement the MuCell technology with a low-cost retrofit of existing twin-screw extrusion equipment. Dumaplast comments that the product that comes from applying the MuCell process to PVC is uniquely suitable for interior cladding, decorative trim, and similar thin-wall profiles. The MuCell microcellular foam process permits Dumaplast to foam thin product cross sections of less than 0.5 mm, while maintaining desirable surface qualities and physical properties. By comparison, other foaming processes, such as processes that use chemical blowing agents, can be impractical or impossible to use for thin-cross-section products. The MuCell process has helped to increase the output of cladding by reducing the viscosity of the PVC melt during processing. By implementing the MuCell process, Dumaplast expects to improve the productivity of its extrusion lines by more than 25%. The MuCell foamed material developed by Trexel and Dumaplast has high tensile elongation, providing the required impact properties of the cladding. The MuCell material exhibits the desired surface qualities and physical appearance. In addition, the material meets UV-degradation standards. Dumaplast is the exclusive license holder of the MuCell process for making PVC claddings, sidings, and roller shutters throughout Europe, including Turkey and the former Soviet Union. MuCell interior claddings produced by Belgium facilities of Dumaplast and its sister company API should be available by the end of this year. Dumaplast's MuCell products will be distributed primarily through DIY outlets. Return to Top | Return to Magazine Articles 98-99 |
