Investigation of the effects of gas-counter-pressure injection molding on the properties and manufacturability of post-consumer recycled polypropylene

Abstract

Abstract. In contemporary times, the most effective strategy for mitigating the environmental effects of plastics and their manufacturing is recycling. However, producing high-quality items from recycled materials remains a challenge. This study addresses these challenges, specifically focusing on the injection molding process for recycled polypropylene. Key issues identified include poor surface finish of the molded items, mold contamination with oily residues, and strong odors during processing. The proposed solution involves the innovative use of gas counter pressure in conjunction with injection molding. The study explores various nitrogen pressure levels to assess their impact. Findings indicate that an optimal pressure level significantly improves the surface quality of the products and reduces the accumulation of dirt in the mold cavities. While gas counter pressure does not mitigate odor emissions, it represents a promising step forward in developing a high-quality recycled polypropylene compound. This approach could pave the way for more advanced recycling techniques, enhancing the quality of products made from recycled plastics.