Environmental project No. 1791, 2015

CoMEKO – Substitution of cobalt in wood protection products


The aim of this project was to substitute harmful cobalt (II) siccatives as well as the anti-skinning agent methyl ethyl ketone (MEKO) from alkyd wood protection products. This was approached using unconventional technologies while maintaining focus on the overall properties of the final product, such as appropriate drying times and storage stability were maintained or improved. The alternative approaches should create fewer concerns regarding human health as well as the environment compared to the substituted compounds.  

This project was divided into a) design of the siccative system and method development, b) Experiments on model systems and c) formulation and test of the wood protection systems. During the course of this project, a number of possible routes to reduction and/or elimination of the use of the Cobalt(II) and MEKO siccative system for wood protection products have been identified. Many of these involve a change in the physical handling of the paint products, avoiding activation of the dryer system prior to opening and use of the paint. Common for many of these solutions are that long-time storage after opening is no longer an option, as the stability of the system is hampered by exposure to oxygen, or a post-activation step. However systems including three new encapsulation strategies to selectively release the dryer system upon application of the paint systems showed promising results, although it was not possible to make a fully stable system within the timeframe of this project. The encapsulation technology could be a viable route to avoiding the use of Co(II) complexes and MEKO in the wood protection products. Further investigations are needed in order to reach systems that can be implemented in wood protection products. 

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