A new mixing section being developed by Robert Malloy, chairman of the Plastics Engineering Dept. at the Univ. of Massachusetts-Lowell, reduces the size of paint particles in reground painted plastics, yielding improved mechanical properties. The patented mixer (U.S. 7021816, 2006), nicknamed "the grater," is designed to blend recycled materials like painted TPO bumpers and multilayer barrier packaging fi lms. The mixer has long axial channels that are closed at the discharge end, forcing the melt over a land with fi ne cross-wise grooves (resembling a cheese grater) to reach the discharge channel. The "grater" reduces paint particle size by 50%, Malloy says. It can use one groove size or progressively fi ner grooves and can be of any length. Malloy is now developing a spiral version. After extrusion with the "grater," painted TPO regrind shows ultimate elongation of about 20% vs. 12% without the grater or 34% for unpainted TPO. Tel: (978) 934-3435 . http://plastics.uml.edu
University of Mass-Lowell
Plastics Engineering Dept
1 University Ave Lowell, MA 01854
Phone (978) 934-3420 Fax (978) 458-4141
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