Development of High Impact, High MFR and Lightweight Polypropylene for Automotive Interiors Application

Plastics nowadays are playing a vital role in the ongoing innovation that is driving the automotive industry to higher performance, safety and sustainability levels. Plastics have allowed automotive designers to meet stringent carbon emission targets and fulfill consumer demands for highly fuel efficient vehicles by reducing vehicle weight while also reducing cost. The next step in weight reduction is to decrease the plastic part thickness further to the minimum possible. But with such reduction in part thickness, it becomes very difficult to meet the side impact crash regulations, and thus it becomes imperative to increase the Impact properties of such light weight materials.

Keeping in line with the above, this paper describes the development of a new blend of Polypropylene which has high impact characteristics to meet crash compliance, high MFR to reduce cycle time and allow for easy filling of low thickness parts and keeping specific gravity in check to reduce weight. This is achieved through usage of high rubber content in Base PP itself in addition to conventional usage of rubber during compounding stage. This paper thus explain in detail our experience of development of such raw material with increased rubber content (to increase Impact properties) and high MFR and optimization of the resulting drop in parameters like tensile strength, flexural modulus and HDT.