New epoxy curing agents for long pot life

Along with the rising demand for lightweight and high-performance materials the importance of composites and related manufacturing processes has significantly increased in recent years. Some important and widely employed processes in this field are vacuum-assisted resin transfer molding (VARTM), pultrusion and filament winding which are used to manufacture a wide variety of composite parts including tools, construction profiles, pipes and pressure vessels to mention just a few. The thermoset matrix systems predominantly applied for these are unsaturated polyesters, which offer a good balance of properties. When improved mechanical properties and chemical resistance are demanded, vinylester and epoxy anhydride systems are the preferred choice. However, the moderate mechanical properties, low alkali resistance and VOC issues of poly- and vinylesters as well as the high curing temperatures required for epoxy anhydride systems are distinct disadvantages of these systems.

Addressing this, Evonik has developed a series of amine-based epoxy curing agents, which are appropriate for application in those processes that require a long pot life such as filament winding, pultrusion, resin transfer molding or casting. With Ancamine® 2167 and Amicure® 101, Evonik offers two standard grades that are recommended for filament winding and casting as they provide medium mixing viscosity, excellent mechanical and thermal properties combined with a high chemical resistance. Compared to Ancamine® 2167, Amicure® 101 exhibits longer pot life and the curing reaction is lower exothermic. For more specialized processes such as high-pressure vessel production which requires lower viscosities and an extended pot life, but can tolerate moderate temperature stability, Ancamine® 2919 is the ideal choice.

The recently developed amine hardener, XR29RB has been designed for standard open bath pultrusion to offer enhanced pot life and lower exothermic reaction heat at moderate thermal stability.

If even higher pot life is required, Ancamine® 2917 can help out. It has an outstanding latency which leads to gel times of more than 1 day.

With this versatile toolbox of crosslinkers, Evonik provides a solid basis for tailored solutions in the field of composites and enables producers of respective composite parts to profit from the benefits of amine-based epoxy curing agents for their products. More detailed information of these curing agents can be found in the table below as well as in the respective technical data sheets.

Epoxy resin used: bisphenol A epoxy resin (EEW 180)
* measured at 23°C, with bisphenol A/F epoxy resin (EEW 190)

Please note that products may not be available in every country. Consult with your area sales manager for further information.