AEM Polymer for Seals and Gaskets with Low Oil Swell and Improved Processing

An AEM polymer – VMX 3110 from DuPont – has been developed for the seal and gasket market.  Compounds made from this polymer have shown improved processing in both injection and compression molding equipment when compared to conventional AEM polymers.  They exhibit improved hot tear and less mold fouling. 

Compounds using this polymer can be formulated to have a combination of low oil swell, low compression set and good low temperature properties.  The compounds have less than 10% volume swell in many commercially available automatic transmission fluids and engine oils.  Typical values for volume swell in IRM 903 oil range from 20 to 30%.  

Fluid aging studies were also done where the physicals after aging were measured at elevated temperatures that are typical of what a seal or gasket will see in the end use application.  The fluid aged compounds had good physical properties both at room temperature and at elevated temperatures. 

This polymer has a cure site monomer that allows for the use of a diamine cure system.  Compounds based on it can be designed to have good compression set properties and good cure speeds without using DOTG.