Hydrolysis-resistance for long life
For critical applications such as those in automotive electronics, long life and reliability are basic requirements. It is often possible that the average operating temperature in modern electronic components increases, e.g. due to compacting. It is also possible that the components are used where they are exposed to the waste heat from the drive system to a considerable extent.
That's why BASF recommends molding control housings from the especially hydrolysis-resistant Ultradur® B4330G6 HR satisfy the very demanding requirements faced by engineering plastics in hot-humid environments. It retains its material properties during long-term testing at 85°C and 85% relative humidity.
Therefore, the level and duration of the stress are key factors as to whether or not an application is feasible using a PBT without improved hydrolysis resistance. Today, the specifications for a number of plastic applications in the automotive sector include tests at elevated temperatures and humidity or tests on changing climatic conditions. These tests can only be passed by HR-modified PBT grades.