Sustainable material for the future - epoxy resin from orange peel - News and insights for the European coatings industry

Epoxy resins can be processed into versatile plastics that are used in various areas – for example in railway vehicles, cars or interior fittings. Usually made from crude oil, alternatives are needed for a more sustainable future. The Orange Oil research project offers a promising approach. The aim is to develop a bio-based epoxy resin system – made from orange peels.

Orange peel is a by-product of orange juice production and is available in large quantities. The German-Turkish cooperation project Orange Oil, in which the SKZ Plastics Centre, the Fraunhofer IMWS and the TÜBITAK Marmara Research Center are working together, has discovered the dormant potential for the development of a sustainable epoxy resin.

In order to produce epoxy resins from orange peel, the orange oil is first extracted and then chemically modified by epoxidation. The epoxidised orange oil can then be mixed with a hardener to form a bio-based two-component system that could be used as an adhesive, as a resin layer for floor coverings or as a matrix component in fibre composite materials.

Due to their outstanding properties, epoxy resins are more widely used in the coating industry than almost any other class of binder. In their new reference book “Epoxy Resins“, the authors Dornbusch, Christ and Rasing explain the basics of the chemistry of the epoxy group and use specific formulations to explain the use of epoxy and phenoxy resins in industrial coatings – including corrosion protection, floor coatings, powder coatings and internal can coatings.

The combination of bio-based epoxy resin with natural fibres in biocomposites is particularly attractive as it offers both ecological and technical benefits. Natural fibres such as flax or hemp have a low density, high specific stiffness and good processability. Another advantage is that they can also be obtained from renewable raw materials and are more environmentally friendly than synthetic fibres.

The bio-based resins and fibre composites will be comprehensively characterised as part of the project in order to determine their mechanical, thermal, chemical and optical properties. The handling of the resin and hardener components as well as the processing technology will also be optimised. In addition, robust technical rules for reproducible process control are being developed. This will enable the bio-based epoxy resins to be used in many areas of application in the rail vehicle, sports equipment, automotive, architecture, shipbuilding and interior design sectors in the future.

The German-Turkish cooperation project Orange Oil started on 1 October 2021 and ran until 31 March 2024. It was funded by the German Federal Ministry for Economic Affairs and Climate Protection (BMWK) as part of the international CORNET programme. The innovative project shows: Waste products from the food industry can become a valuable raw material for plastics technology and thus make an important contribution to resource conservation and climate protection.

Source: Industrieverband Klebstoffe e.V.