Adduct hardeners and REACH

When manufacturing epoxy resin hardeners with specific properties, the amines used need to form adducts, involving adding compounds. Using the current technique in accordance with REACH, this produces new substances that need to be registered accordingly.

Adduct hardeners and REACH. Image: semion-Fotolia -

Klaus Reinhold of Worlée discusses the resulting problems and ways forward.

What problems do adduct hardeners pose with regard to REACH legislation?

Klaus Reinhold: To produce epoxy resin hardeners with specific properties, the amines used need to form adducts. This involves adding compounds containing epoxy groups such as bisphenol A diglycidyl ether to one or more amines. Using the current technique in accordance with REACH, this produces new non-polymeric substances that need to be registered accordingly. To keep the registration work and the associated costs in check, the industry and the ECHA agreed to no longer use mixed adducts but to work with in situ adducts (model substances). These are then registered via REACH.

What is the situation with registrations, is it feasible to streamline products?

Reinhold: At present, the industry has three “model substances” in the registration process: the adducts IPDA with bisphenol A diglycidyl ether, MXDA with bisphenol A diglycidyl ether, and a polyaminoamide with o-cresyl glycidyl ether.

Do you see the possibility that products will have to be cut from the portfolio?

Reinhold: The three substances in the registration process are important adducts when manufacturing epoxy resin hardeners, however, they only cover part of the present commercialised product portfolio in this field. In future, specialised solutions not based on the abovementioned adducts will disappear, unless the customer is prepared to take on the registration costs for these specialised solutions.

What does Deutsche Bauchemie, the German Construction Chemials Industry Association, suggest as the way forward?

Reinhold: Deutsche Bauchemie takes the view that the aim of adding epoxides to the hardener formulation is to adjust the physicochemical properties of the hardener for the intended use and to stabilise the product. It is assumed that there is no intention to produce epoxy amine adducts. Annex V of the REACH regulation stipulates that these substances do not need to be registered. However, to be on the safe side, Deutsche Bauchemie has advised its members to pre-register or register the adducts. The association therefore refers to adduct hardeners as “epoxy resin-stabilised amines”. However, it is not clear whether this reasoning is shared by the ECHA.

Your company works with adducts that come under the ECHA definition of a polymer. What does this mean in terms of REACH registrations?

Reinhold: Worlée wanted a way of ensuring it could continue to pursue new joint developments with its customers using the entire range of available amines and epoxy compounds. The only economically sensible option uses the ECHA polymer and monomer definition. The crucial point is that we can offer highly functioning epoxy resin hardeners from polymeric components for virtually all the applications covered by these products today. Using this technology, which does not require REACH registration, means that even in the future, customers can continue to successfully manage development in this product field. There will not be any delay caused by the registration process. There will be significantly less work involved with new developments using this technology than for a substance that requires registration, and importantly we can also offer our customers specific solutions in future that enable them to maintain their entire product range.

The complete interview can be found in the September issue of the European Coatings Journal.

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