Application of allocation methods in open-loop recycling systems: The carbon footprint of injection molded products based on ABS, PA66GF30, PC and POM

Abstract

The consumption of recyclates in open-loop recycling systems raises the question in Life Cycle Assessments of how environmental impacts caused by raw materials and recycling can be allocated to the corresponding products. To solve the multifunctional issue of material flows, this study applies the 50:50 method as well as the cut-off and end-of-life approach using the Circular Footprint Formula across a cascade of three product life cycles. This analysis is based on injection molded products made of virgin and secondary materials, which consist of ABS, PA66GF30, PC and POM from post-industrial waste. The loss of quality due to production and mechanical recycling processes is reflected in the decrease of tensile strength. By quantifying the impact of allocation, this paper highlights the effects on the Product Carbon Footprint according to ISO 14,067 to show that a 50:50 as well as a cut-off allocation is suitable for the assessment of technical plastics.