Community Research and Development Information Service - CORDIS

Development of new more ecological , environmentally friendly resins

The development of resins with lower organic solvent (methanol) contents and reduction of free phenol and formaldehyde levels to minimise the environmental impact has been an important aspect of this project. Standard resins currently applied in the impregnation process of glass fibres are most frequently based on methanol at levels of up to 40%. Furthermore, free monomers present in the resin do contribute to VOC emissions. This goal was to be achieved by altering the molecular structure of the resin and/ or its weight distribution, i. e. by changing the catalyst, its quantity or percentage, the phenol/ formaldehyde ratio, etc.

All the applications where phenolic resins are used nowadays are suitable for these newly developed resins. The primary users are FRP producers supplying mainly into the abrasive manufacturer, transport, electrical, and the building sector, among others. The production process of prepregs is basically applied in this form all over Europe, even the entire world. Large quantities of organic solvents are emitted into the atmosphere. Furthermore the working environment in the production sites will be largely improved by any reduction of organic solvents used in the process.

It can be concluded that the objective has been mostly achieved. A number of resin systems were developed which do contain largely reduced amounts of free monomers and thus emit less organic volatiles in the manufacturing process, without compromising its impregnation properties. A reasonable compromise between flexibility and surface tack could be achieved only by modifying the novolac resins. Modified novolac resins were developed and subsequently tested in the prepreg manufacturing and the grinding wheel production process to ensure that their performance in the process. The idea to move to water based resins would eliminate most of the organic volatile compounds present in the resin, but does have severe limitations as the commonly applied phenolic resins are insoluble in water. The objective to replace organic solvents by water borne systems has not quite been met, as the newly developed dispersion systems do still lack storage stability and do not provide acceptable product qualities. The obvious target has to be to develop lower viscosity dispersion with improved impregnation properties.

More development work will have to be invested beyond the scope of this project to further improve the properties of water-borne and low solvent impregnation resins.

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Hexion Specialty Chemicals GmbH
Gennaer Str. 2-4
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