Polypropylene/polyethylene two-layered by one-step rotational molding

At present, a two-layered product can be molded through various processes. The rotational molding process is a thermoplastics process that can produce products with a two-layered structure; however, it requires special equipment or additional steps in the processing, which make the processing more complex. However, previous research has shown that, through the use of materials with different particle sizes and melting points, two-layered products can also be molded. Thus, this research uses an axial powder flow apparatus to determine the possibility of a two-layered molding between polypropylene (PP) and linear low-density polyethylene (LLDPE). The differences in the particle shapes of a PP homopolymer and copolymer have been considered. The particle sizes of both PPs were determined to be larger than that of LLDPE, and were mixed in a ratio of 50:50 (%wt) using a dry blending method. The results of this experiment show that the two-layered molding of PP and LLDPE using an uncomplicated technique for rotational molding has a high probability of success.