The closed method of manufacturing reinforced plastic products will soon give SMEs big
advantages compared with existing open laminating methods: lower emissions, safe working
conditions, and reduced air handling costs. In the closed method solvent emissions of the
resin binder are significantly reduced because the resin is absorbed under negative
pressure into the reinforcing fibres and the curing takes place in a closed space.
Less resin is needed in the closed method, the manufacturing process is cleaner, and the
job will become more attractive to the industry's workers. The present method of manual
laminating and resin transfer moulding will require better air handling in the future
because the permitted level of emissions will be lowered and laminating emissions to
outside air will be prohibited entirely.
Reinforced plastic is used especially in the manufacture of boats, body shells, sporting
goods, body armour, process industry containers and pipes. The closed method of
manufacturing reinforced plastic is especially suitable for small and medium-sized series
The challenge for the future is to develop a method by which reinforced plastic products
can be made safely and moreprofitably than by the present method of open lamination, while
retaining their hard surface layer and the use of colouring agents. Fire-proof polyester
resin suitable for the underpressure technique will also be needed.
The new laminating method has been developed by VTT Chemical Technology The Laboratory
of Lightweight Structures at Helsinki University of Technology, Ahlström Glassfibre Oy,
FY-Industries Oy Composites, Neste Chemicals Oy, Nautor Oy and Profile Component Oy. The
work was financed by the National Technology Agency, Tekes.
VTT Chemical Technology, Jyrki Siikonen, tel. +358 3316 3522 or +358 40 746 7602.