For many years, DOTG was used as the primary accelerator for AEM compounds because it provided fast cure speeds and low compression set.
Many different accelerators have been evaluated as replacements for DOTG, but none has the same combination of fast cure speed and low compression set.
An example is when a compound based on AEM G and DOTG has to be reformulated to eliminate DOTG, while not sacrificing any compression set properties.
This benefit is important for compounds that cannot use DOTG as the accelerator.
Table 3 shows an AEM GLS compound with DOTG as an accelerator compared to AEM GLS and AEM 3110 compounds with a DBU based accelerator.
Initial shot After 35 shots AEM G compound 25% 50% AEM IP compound 25% 20% Table 3 - compression set study of AEM compounds with and without DOTG as the accelerator AEM GLS AEM GLS AEM 3110 with DOTG with DBU with DBU AEM GLS 100 100 - AEM 3110 - - 100 Hindered amine AO 2 2 2 Octadecyl amine 0.
The situation with respect to DOTG is changing, and this is discussed in more detail in other presentations, including reference 3.
It was difficult to find an accelerator that worked as well as DOTG as far as speeding up the cure rate and improving the compression set.
Either DOTG or a combination of DOTG with DPG is used with either HMDA or HMDC.
DOTG can be replaced by both Vulcofac ACT 55 and XLA-60, which are based on the same active chemical substance.
Studies have shown that, when used with other curatives, DOTG can produce o-toluidine.
With Compound A we see that replacing the DOTG with Rhenogran XLA-60 reduces the scorch safety and shortens the cure rate, but matches the Mooney viscosity and shows improved final torque.