Quality Assurance of Recycled HDPE in the Plastic Packaging Industry

Abstract: The recycling of plastic has the potential to support circular material use, thus decreasing the need for virgin plastics. However, there is an existing issue with assuring quality of recycled plastic materials, causing finished products to perform with poorer properties and unexpected deviations. Based on a thermoformed plastic packaging product, Product Y, made of recycled high density polyethylene (HDPE), this thesis is written in collaboration with Company X and researches how to assure quality of Product Y. The purpose of the thesis is to research how Company X can achieve uniform quality on the finished products, regardless of when or where the recycled HDPE is manufactured. To fulfill the aim of the thesis, the research questions to be answered are: 1. What affects the quality of recycled post-industrial and post-consumer HDPE to be used for packaging? 2. What is most important regarding the recycling processes to achieve high- quality plastic? 3. What are the issues regarding plastic recycling processes globally? The method is divided into three parts; a literature study to gain necessary background knowledge on the subject, conducted interviews with internal and external industry representatives to gain insights on how the industry works today, and material testing to compare if the results are corresponding to expected results. The material testing includes Shore D hardness test, measuring of material thickness, tensile test, melt flow index, differential scanning calorimetry, and thermoforming test with a following visual inspection of the finished products. After analyzing interview findings and material testing, it was concluded that conducting polymer tests for different material properties is important for quality assurance. The customer and plastic processing company should agree on the testing procedure. Cooperation between the involved parties is crucial for successful quality assurance of the recycled material. Transparency, global standards, and a coordinated approach will help overcome quality assurance challenges in plastic recycling today.