New technique to deliver environment-friendly and innovative coating for composite parts
Composites for the transport and automotive sectors must meet weight, cost and production rate requirements. Traditional composites used in the automotive industry have typically utilised high-cost technology for autoclave curing or sheet moulding compound. Using Resin transfer moulding (RTM) can provide optimal efficiency in terms of cost and production rates, while maintaining the same level of performance and quality. The EU-funded ECOGEL CRONOS (High productivity manufacturing process of composite parts based on zero emissions fast curing coatings and heated moulds) project developed an RTM method by using powder gel coats. In addition, it also developed new moulding technologies. To develop the powder gel coat, project partners first had to formulate a powder resin system. They prepared different resin modifications to improve powder gel coat adhesion to various resins, to develop conductive gel coats for mould construction, and to improve the thermal resistance of epoxy resins used in the manufacture of hot skins. Preforms were utilised during the manufacturing process. The ECOGEL CRONOS team assessed the influence of preforms in cycle time reduction. It determined that this contributes to drastically reducing cycle time through automation procedures. Researchers employed simulation programmes to determine RTM mould design and electrical thresholds in conductive powder gel coat formulation. They obtained non-conductive and conductive powder gel coat formulations, and used electrically heated technology to manufacture demonstrator moulds. The electrically conductive hot skin mould technologies are based on laminates made of carbon-fibre plastics for mass production parts specifically for agricultural equipment and goods transport. Lastly, a life-cycle assessment of powder gel coat was performed. ECOGEL CRONOS powder gel coats provide significant benefits to RTM production plants in terms of costs, safety, the environment and process flexibility. Curing time is significantly reduced compared to conventional liquid gel coats. Opting for non-conductive powder gel coats over their traditional alternatives could reduce the emissions of potentially harmful vapours known as volatile organic compounds by a factor of 30. This will also eliminate styrene emissions arising from gel coats in the workplace.
Keywords
Composite parts, powder gel coats, resin transfer moulding, ECOGEL CRONOS
