An Online Extrusion-compression Molding Method to Produce Wood Plastic Composite Packaging Boxes

Abstract

Wood plastic composites are widely used to manufacture profiles by extrusion but rarely applied to make products by injection or compression for its poor flowability. Wood plastic composite packaging boxes were manufactured by both self-designed online extrusion-compression and traditional injection molding methods with different formula. The mechanical properties, buckling deformation, production capacity and final passed yield of packaging boxes and energy consumption was investigated with the two different methods. We find that the filling of bamboo fiber into polyolefins improves tensile strength but brings down impact strength in both processing method. However, for online extrusion-compression molding we can obtain a better tensile and impact strength. With the increase of bamboo fiber concentration and decrease of HDPE/PP mass ratio the buckling deformation declines, and a smaller buckling deformation can be obtained by the online extrusion-compression molding with respect to tradition injection molding. The comparison of energy consumption between the two processing methods reveals that it is a cost-effective way to manufacture wood plastic products, saving about 29.81% energy compared with traditional injection molding. Online extrusion-compression molding technique can be widely used to manufacture wood plastic composite products of irregular structure and large-format.