How to Evaluate the Compatibility of Thermoplastic Materials with Lubricants 2010-01-0918

Over the past few years the use of thermoplastic materials has been broadened considerably in many different parts of automotive components, such as door handles, dashboards, interior trim, seat covers, gearshift linkages and gearboxes. This paper highlights the importance of compatibility issues of polymers coming into contact with lubricants. In order to enable a proper function of car components, advanced elaborated testing should be conducted. Using the example of compatibility tests, this paper illustrates how the “lubricant” design element contributes to improving the function of polymers. Moreover, relevant test rigs and results are described and discussed.

Thermoplastic materials and lubricants are essential for the construction of many technical applications. Therefore, it is very important to consider the compatibility of both components. This however raises the question of how to evaluate the compatibility. Contrary to rubber materials, there is no general standard like the ISO 1817 for thermoplastic materials [ 1 ]. Furthermore, it is difficult to transfer test results from lab tests to technical applications. Currently some OEM and tier 1 suppliers for the automotive industry are formulating standards to define acceptable tests and give certain ranges for the testing. These standards are generally focusing on tensile tests and sometimes on environmental stress cracking (ESC). This article aims to show some different methods for the immersion procedure and their limits. Materials like PA 66, POM, PP and PC will be discussed. Influences caused by additives and solvents will also be considered.