Morphology and properties of PC/ABS notebook computer shell prepared by a combined in-mold decoration and microcellular injection molding process

Abstract

In this paper, the PC/ABS notebook computer shells with PET film were prepared using a combined in-mold decoration and microcellular injection molding (IMD/MIM) process. Then the surface quality, morphology, impact toughness and wear resistance were investigated. The results shown that the surface quality is improved by IMD/MIM technology. The three dimensional surface roughness value (Sa) was about 1/3 of that of MIM parts. The cross-section of IMD/MIM samples have three layers. The first layer is a PET film decoration layer with about 132 µm thickness, followed by skin layer (about 22 µm) and foam layer. The range of thickness of the foam layer for the different specimens is about 7803 µm–7820 µm.The cell diameter is between 0.532 µm and 0.638 µm, which is about 2 times than that of MIM parts. Compared with MIM parts, the shape of the bubbles of IMD/MIM parts is ellipsoid with thinner wall. Moreover, the impact toughness of IMD/MIM parts are higher. The best impact toughness is 21.02 KJ/m² within the scope of this experiment, which is 74% higher than the corresponding MIM part under the same foaming process. This may due to the PET film and micropores could block the initiation of the tip crack. Meanwhile, the IMD/MIM parts have excellent wear resistance property. In most cases, the wear rate of IMD/MIM parts is about 36.6% of MIM part under the same condition.