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CYPHOS® IL 169 - A Latent Catalyst for Baked Epoxy Anhydride Systems

Thermoset chemistry is made up of a variety of different systems (epoxy, polyester (PE), polyvinylchloride (PVC), etc.) and is used in a wide range of applications such as aerospace and wind energy (composite materials). In many cases, speed of production is a critical factor in these processes. Traditionally, thermosets like epoxy anhydride curing are much slower and require catalysts, even in heat cured applications. Solvay’s CYPHOS® IL 169 (Strem Catalog: 97-1330) is a latent catalyst that can be premixed in the “B” component of a 2K epoxy system. CYPHOS® IL 169 (Strem Catalog: 97-1330) provides low viscosity and long pot life, fast curing at high temperatures compatible with a continuous process (Pultrusion, Filament winding, etc.), deliver high Tg, high clarity and no undesired side reactions. (1-5) The features and benefits of systems cured with CYPHOS® IL 169 (Strem Catalog: 97-1330) make it ideal for these ever evolving applications.


The liquid phosphonium salt CYPHOS® IL 169 (Strem Catalog: 97-1330) is soluble in many common epoxy systems, and when premixed with the anhydride (MTHPA, NMA, etc.) show no reactivity for extended periods. The high thermal stability of the molecule makes it ideal for heat cured systems such as pultrusion and filament winding.


CYPHOS® IL 169 (Strem Catalog: 97-1330)

For curing, CYPHOS® IL 169 (Strem Catalog: 97-1330) is just as effective as common imidazole curing agents and can be effective at curing with loading levels as low as 0.5 wt.%. By comparison however, when looking at the cure profiles, the CYPHOS® IL 169 (Strem Catalog: 97-1330) has a much more homogeneous and consistent thermoset formed. The ultimate effect of this is a more homogeneous product which leads to less production deformations.


An important application of epoxy anhydride chemistry is in LED encapsulates and other technologies which require the material to be more transparent. Many nitrogen based technologies generate a distinct orange color. By comparison – the CYPHOS® IL 169 (Strem Catalog: 97-1330) gives us a much more transparent color and under the right conditions can generate thermosets that are water white in color.


Left: CYPHOS® IL 169, Right EMI24

Lastly, there are many benefits to evaluating the use of epoxy/anhydride systems as a thermoset relative to competitive technology such as PE and PVC. Epoxy anhydride systems are styrene free (unlike PE) and offer safer working conditions for open bath systems. Epoxy anhydrides also offer superior binding to composite materials such as carbon fiber compared to PE and PVC. Finally, epoxy anhydride systems are typically much more durable in terms of chemical and thermal stability (useful under harsh conditions).

CYPHOS® phosphonium ionic liquids are readily available in high-purity at commercial and lab scales.  Custom packaging and logistics support is available at commercial scale. To learn more about other ligands for catalysis, please refer to the Solvay offering at Strem or the Solvay website.

*All systems are a cured system of Araldite® LY 1556, Epiclon®B570H and either CYPHOS® IL 169 or EMI24


  1.       US Patent 20040086720, May 6, 2004.
  2.       ACS Sustainable Chemistry & Engineering,2016, 4, 481-490.
  3.       US Patent 20190169423 A1, June 6, 2019.
  4.       WO patent 2017202771 A1, November 30, 2017.
  5.       WO Patent 2017212177 A1, December 14, 2017.


Featured Product:

97-1330 Tributyl(ethyl)phosphonium diethylphosphate, 95% [CYPHOS® IL 169 PHOSPHONIUM SALT] (20445-94-7)


Related Products:


Phosphorus Ligands and Compounds Booklet

All products sold in collaboration with Solvay



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