Chauhan, V. and Ray, A., "Root Cause Analysis of Discoloration of Polypropylene in Automobile Interiors," SAE Technical Paper 2013-01-0615, 2013, doi:10.4271/2013-01-0615.
Presently Automobile industries are struggling to restructure their products to reduce the emissions and increase fuel efficiency. Plastics offering advantages over metals have led to the usage of wide range of polymers in automobiles. Their benefits include light weight, ease of fabrication, intricate shapes, and resistance to harsh chemical environment. Above all, the major advantage of plastics is that, the part can be manufactured in various colors depending on the needs of the designer.Currently the trend is shifting towards the light colored interiors, which make the car look more spacious and aesthetically upmarket. But with the usage of light colored interior plastic, problem related to discoloration of these parts has become prominent. Though this problem persists in dark colored plastics but not noticeable.Polymeric degradation may occur during raw material manufacturing, thermal processing and subsequent exposure to the environment. In vehicles with beige colored interiors phenomena of red color blooming out on the parts' surface (in very fine powder form) is observed.This paper explains the various causes of discoloration of Polypropylene parts along with root cause analysis and countermeasures.