Latest development in automotive weatherseal profiles

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  • Combination of amorphous EPDM rubber and propylene-based elastomer
  • Density reduced by 10%
  • Compression load deflection (CLD) maintained
  • Application: automotive sponge weatherseal profiles

ExxonMobil Chemical has introduced a new approach to formulating EPDM compounds for automotive sponge weatherseals. Combining an amorphous, high-diene Vistalon EPDM rubber with a propylene-based elastomer (Exxon IT0316), produces a compound that can help to reduce the density of the sponge profile, while maintaining the key properties that meet automotive weatherseal specifications for automakers.

Providing profiles with differentiated properties

Using this new approach to tailor EPDM rubber compounds allows manufacturers to reduce part cost while broadening their range of sponge profiles with differentiated properties, according to the company. Vistalon EDPM rubber is widely used for automotive exterior-sealing systems, especially sponge weatherseals around the doors, trunk and hood. Due to its air and ozone resistant properties, it insulates against water, dirt and noise over the lifetime of the vehicle.

Density reduced by 10%

The new formulation, based on metallocene polymerization technology, allows the design of high-performance compounds with tailored properties through the precise control of the molecular architecture and co-monomer introduction. Tests on an ultra high-frequency (UHF) extrusion line show that blowing-agent efficiency is optimized without compromising the sealing properties of the sponge profile. The compression load deflection (CLD) and compression set (CS) are maintained, and density can be reduced by 10 percent. The uncured, soft-sponge compound also exhibits more green strength, improving weatherseal handling. Compounders can tailor the performance of the sponge weatherseal to produce a profile that has a similar density to an EPDM compound but with a higher CLD or a profile with a lower density but a similar CLD.

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