High Performance Unfilled Polypropylene Material for Light Weight Interior Trims 2022-01-0338

Light weighting is important to improve energy efficiency in the automotive industry. In this paper, high performance unfilled polypropylene copolymer (PPCP) material was selected and developed to reduce weight and cost without compromising on functional requirements for interior trims such as door trims, lower pillar trims, scuff trims and rear quarter trims (RQT). Interior trims are loaded with challenging requirements such as stiffness, dimensional stability, haptic feel, scratch resistance, cleanability, thermal stability, toughness, low emission and weathering resistance. Reactor polymerized PPCP material compound met these requirements by having ultra-flow behavior, optimum tensile strength, balanced modulus - impact strength, scratch resistant, low emission and improved thermal properties. This is a ready to mold material used in injection molding process.

This unfilled polypropylene copolymer material has been explored for thin wall interior trims with thickness of 2.5mm. These trims have critical functional requirements such as load versus deflection criteria, push effort to fit the fastener, snap effort with respect to interface bezels and addons, doghouse stiffness, door pull durability, gap and flushes aspects. Structural durability of the design was validated by virtual engineering. Part design and material combinations with better tooling design iterations were analyzed by using mold flow analysis. Complete product performances were being validated for predefined key test metrics such as structural durability, thermal aging, cold impact, scratch resistance and weathering criteria. This part met required specification. The combination of material, optimized part and tool design led to weight savings, good surface quality, dimensional stability under sun load, haptics improvement and considerable cost reduction.