Konzeption, Entwicklung und Evaluierung eines Messsystems zur sortenreinen Klassifikation von fluoreszenzcodierten Kunststoffen im Rahmen des Kunststoff-Recyclings(Conception, development and evaluation of a measuring system for the classification of fluorescence coded plastics within the framework of plastic recycling)
UNIVERSITAET DER BUNDESWEHR MUENCHEN NEUBIBERG (GERMANY F R) NEUBIBERG Germany
Plastic has become one of the most versatile and widespread materials in the world. Extensive demand however has a significant ecological and environmental impact because production of plastic goods is based on fossil resources crude oil, a high consumption of energy and significant CO2 emissions. The demand of polymers in combination with their high durability following rather short life phases enforces the flow of plastic waste into landfills. Given these facts, plastic recycling has become indispensable. In order to produce economically attractive products based on recycled plastics, mono-fractional compositions of waste polymers are required. However, existing measurement technologies such as near infrared spectroscopy used in sorting facilities show limitations with regard to the separation of complex mixtures of plastic flakes, especially when dark and black plastics are part of them. An innovative approach to overcome these obstacles and provide high sorting purities is to label different types of plastics with unique combinations of fluorescence markers also known as tracers which can be considered as optical fingerprints. They are incorporated into the virgin plastic resins at ppm parts per million levels during the production process and do neither affect the visual appearance nor the structural and mechanical integrity of the materials. The aim is to access the practical use of this concept in industrial processes. For that reason, an industrial applicable spectroscopic measurement system has been designed and implemented that identifies polymer flakes with a size of few millimeters transported on a conveyor belt in real time based on the emitted fluorescence of incorporated organic markers. Additionally, to the implementation of the opto-electrical measurement system, a multi-threading software application has been developed and realized which controls the hardware and collects the measuring data and finally classifies the data.