Abstract
Keywords - Door panels, polyolefin, one polymer class, recycling, polypropylene fabrics.
Abstract - The development of materials and technologies for making parts using materials of one only polymer class is become increasingly relevant for the automotive industry. The objective is to make components which are entirely recyclable at the end of the vehicles life.
These were the premises for a project aimed at the construction of door panels entirely made of polyolefin based materials (skin, structural plastic supports and accessories). We started by studying and developing polypropylene fibre upholstery fabric with characteristics similar to those of polyester normally used for fabric central inserts. In parallel, we identified a compatible type of polyolefinic foam to be arranged between the fabric upholstery and the structural support. Finally, we identified a suitable polyolefinic base skin consisting of TPO foamed laminate readily available on the market for the skinned door belt.
After focusing on trimming materials, we turned to developing and characterising the plastic material to be used for structural supports. We identified the most suitable to be vegetable fibres filled polypropylene suitable for compression moulding with injection of door fastening ribs directly in the mould. We developed a new type of polypropylene with better scratch resistance for the lower part of the panel (normally made of rigid injection moulded plastic).
Finally, we studied a high-fluidity polyolefinic plastic to obtain thin, cell-like, complex structures capable of satisfying stylistic requirements and passing the cold impact tests (-20°C) stated in specifications for the speaker grid also made of homogenous, compatible material.
After developing, characterising and testing the single components, we subjected the resulting door panels to qualification and tests in accordance with current Fiat Auto standards for use in a vehicle being launched on the market.