JEC COMPOSITES MAGAZINE - Issue #54 - January 2010 - 58

KNOW-HOW Mould g…/… DEMOCRAT, an electrostatic process fillers) and the release of VOC emissions into the atmosphere. Using electrostatic deposition in a conductive organic mould cuts down significantly on VOC and aerosol emissions. Organic moulds, inexpensive and easy to make, are the type of mould used most in the hand lay-up and RTM markets. The polyester or epoxy used to make these moulds are insulating materials, which rules out the use of electrostatic processes. The proposed innovation breaks with current technology by creating an organic mould that is conductive, both throughout and at the surface. The innovation can help to reduce both the cost of composite processing and the emission of pollutants into the air. The technical advantage is that it makes the inner lining of the mould conductive by using an inherently conductive polymer filler instead of metal fillers to control the system’s flow properties and the composite’s electrical properties. Creating the conductive composite mould involves the following steps: - creating a master mould to match the exact shape of the desired part, - depositing and curing a conductive polymer compound that includes one of the Paniplast conductive polymers in the master mould, - integrating the electrical connectors, - laying up the laminate mould inside the master mould; removing the mould produced. How electrostatic deposition works In the production of composite objects in materials like polyester or epoxy, the resin droplets become negatively charged when they come into contact with the electrode located at the spray gun outlet, which is brought to a voltage of 50-100 Kv. The droplets follow the electrical field lines and are attracted to the surface of the organic mould, which has been made conductive by the above-described process. Fig. 5: Manufacturing steps for creating a conductive mould for a boat hull, up through electrostatic spraying of the gelcoat on the mould. a) Creating the mould for the boat hull with conductive zones (in black) separated by a non-conductive zone (in white). b) Installing the electrode to ground the central part of the mould. c) The boat hull (in white) created in the mould, after electrostatic spraying of the gelcoat. - the 80-100% resin transfer rate considerably saves on material, - the electrostatic process attracts the droplets to the mould, reducing the dispersion of a droplet “fog” and, as a result, the release of solvents and other pollutants into the air, - deposition is more rapid and even, and it is possible to create thin layers of resin or paint. Application areas • Boating: yachts, motor and sailing boats • Wind turbines: blades, nacelles, etc. • Automotive: bodies for trucks, buses, camping cars, tramways, trains, etc. • Swimming pools, showers, etc. • Aviation: gliders and ULMs. More information: www.rescoll.eu Contact : jose.alcorta@rescoll.fr Fig. 4: Principle of electrostatic spraying. The DEMOCRAT process has the following advantages over current processes: jec composites magazine / No54 January 2010

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JEC COMPOSITES MAGAZINE - Issue #54 - January 2010

Table of Contents for the Digital Edition of JEC COMPOSITES MAGAZINE - Issue #54 - January 2010