Composite materials and structures coated in the mould
Composite materials are increasingly being used to build structures like boats and wind turbines. These materials, which contain strengthening fibres held together in a resin matrix, are strong, lightweight and can be moulded into complex shapes. To protect the composite material and to provide a high-quality finish, manufacturers usually apply a resin called gelcoat to the material's surface. Currently, they do this in an open-mould system that releases potentially harmful chemicals into the air or the workplace. The EU-funded INGECT (An innovative environmentally friendly gelcoating technology for composites for marine and wind-turbine applications to reduce VOC emissions, processing time and cost) initiative worked to develop a gel-coating technology that reduces harmful emissions. Its main focus was to reduce exposure to a gelcoat component called styrene that vapourises easily and has been linked to neurological disorders and cancer. Project partners investigated ways to gel-coat composite materials while enclosed within the mould tool, thus reducing styrene emissions into the air. In one approach, called in-mould gel-coating, an impermeable spacer fabric provides a pathway through which the gelcoat can flow during the moulding process. An alternative method, called in-mould surfacing, involves first placing a silicone membrane into the mould. After moulding, the membrane is removed and replaced with gel-coating material, which is injected into the space previously occupied by the silicone membrane. Prototypes have been tested, but both technologies require further work to be commercially viable. Once these processes are improved, they will make the manufacturing workplace safer while reducing environmental impact, and also lower manufacturing time and costs.
Keywords
Gelcoat, composite materials, emissions, wind turbines, INGECT, moulding
