Study on improving the quality of high content recycled PE foamed board by enhancing screw elongational effect in mixing process

Abstract This paper focused on improving the content of recycled PE in the foaming board and the compatibility of recycled PE with other materials and fillers, reducing the unmelted recycled PE particles in the recycled PE foaming board, and enhancing the foaming density and quality of the recycled PE foamed board. In this paper, the elongational mechanism was applied to the design of the screw mixing section, and a new type of elongational screw was designed to improve the mixing effect of PE and LDPE and fillers by strengthening the elongational effect of the screw. Through simulation analysis and experimental comparison, it was found that the mixing capacity of the strong elongational mixing section was 1.3 times higher than that of the ordinary mixing section. The mixing quality of pre‐foaming compound and the foam quality and density of foamed board were studied by macroscopic and microscopic showed that the unmelted particles and filler aggregates in the extruded preform prepared by the new elongational screw were significantly reduced, while the foaming density and extrusion production capacity were significantly increased, especially the formula of pure recycled PE foamed board. It could be seen that increasing the elongational effect played a crucial role in improving the melting of the blends in the extruder, the crushing and refinement of the filler aggregate, and improving the fluidity of the blend foaming materials in the molding foaming machine to avoid the lack of materials in the cavity.