Advancure Hexamethylenediamine Curative in Guanidine-Free Cure Systems for Vamac

摘要

DuPont Vamac~R ethylene acrylic elastomers (AEM) are designed to withstand high and low temperatures and aggressive new automotive fluids in under the hood automotive applications such as seals, gaskets, ducts, hoses and dampers. The most frequent cure system rsed to cure AEM is a combination of HMDC (hexamethylenediamine carbamate) with DOTG (di-o-tolylguanidine) or DPG (diphenylguanidine). Previous studies show that hex amethylenediamine (HMDA), can replace HMDC in this type ofcure system with similar cure and physical properties at a much lower cost. Advancure~(TM) is a 47% active liquid concentrate of HMDA absorbed on amorphous silica in powder form. Advancure~(TM) is based on patented curing technology from DuPont and is enhanced with an innovative dispersion technology from Chem Technologies. In this paper we will refer to Advancure~(TM) as HMDA Dispersion. The European Union under REACH will ban the use of guanidine accelerators such as DOTG and DPG due to carcinogenic concerns. Several chemical manufacturers have come up with alternative cure systems using HMDC and amine complexes to replace the guanidins. Since HMDC breaks down to HMDA during the curing of AEM it was theorized that HMDA would also work with the amine complexes. This paper gives a short review of the previous studies on HMDA/guanidine cure system and' then focuses on the recent work that shows the HMDA system can also function well with the amine complexes in a guanidine-free cure system for curing AEM.