BASF (Ludwigshafen, Germany) has already built somewhat of a reputation in developing low-warpage injection molding grades based on a blend of polybutylene terephthalate (PBT) and acrylonitrile-styrene-acrylate (ASA). Take, for example, Ultradur S4090 GM13, a PBT/ASA reinforced with minerals and glass fibers that displays a shrinkage ratio of 0.70/0.80. Moving one step beyond, the new grade—Ultradur S4090 GM11—boasts a ratio of 0.95/1.0 as measured by the ISO 294 standard.
This unprecedented homogeneous shrinkage results in minimal warpage, according to the supplier. In combination with its good mold removal behavior from the injection mold and its good surface quality, this property is of particular interest when it comes to manufacturing large-surface parts for automobile interiors, according to BASF. —[email protected]