boat manufacturer Halmatic won the JEC Composite 2000 transport innovation
prize in Paris for the world's first glass-reinforced thermoplastic boats.
The competition was open to companies from any country that had developed
an exceptional composite solution in terms of technical quality, market
openings and customer/supplier partnership. The Halmatic boats are one
of the first results of a three-year development project, funded by the
European Commission, to develop an environmentally friendly replacement
for GRP (glass-reinforced polyester).
project involves the low pressure moulding of continuous glass-fibre-reinforced
thermoplastic mats and offers a totally new way of fabricating large surface
area structures. This material offers excellent mechanical performance
and is easy to recycle - and there are no solvent emissions during processing.
for hand lay-up GRP
plastics (FRP) have grown to dominate the market for large scale
structures in all types of transport but particularly in boatbuilding.
In Western Europe alone, over 300,000 tonnes of FRP marine products
are made each year in open moulds using the hand lay-up or contact
moulding process. This involves laying down layers of glass fibre
matting impregnated with a liquid resin in an open mould to build
up the required thickness.
90% of these products use polyester resins contain high levels of
styrene monomer, a solvent that is emitted during the manufacturing
process. The styrene also makes it difficult to store the resins.
Styrene emissions are a major problem when working in large open
moulds as ventilation is often difficult and expensive - and personal
ventilators are uncomfortable to wear.
stringent health and safety regulations have already reduced acceptable
styrene levels in the workplace to typically below 50 ppm in most
of Europe. Even tougher 25 ppm limits in Scandinavia are leading
to widescale abandonment of GRP boat building in many area. And
levels similar to those in Scandinavia are expected to be introduced
throughout the EU in new Commission directives.
group led by UK composite materials design and development specialist
Euro-Projects therefore set out to develop an environmentally acceptable
alternative. Partners included boat and wind-turbine manufacturers,
materials suppliers, research institutes and certification organisations
from Denmark, France, Germany and the UK. The result of the project
was a switch to a thermoplastic process that is clean and efficient
- and poses no solvent emission problems.
The ENVIROCOMP process is based on the use of Twintex, a co-mingled
strand of glass and polypropylene (PP) fibres - 60% glass/40% PP
- developed by French glass specialist Vetrotex. The strands are
woven into a fabric which can then be draped into a mould together
with any cores or inserts and heated to around 190ºC. The polypropylene
then melts. A vacuum is applied to ensure that the glass fibres
are properly 'wetted' or impregnated by the molten thermoplastic.
include much cleaner processing, the ability to recycle offcuts
and complete mouldings (so avoiding landfill costs), resistance
to water and chemical attack, and much better impact performance
and delamination resistance than polyester," claims Gerry Boyce
of Euro-Projects. "And while material costs are the same as
polyester, there is much less labour involved as it possible to
achieve the desired thickness with one shot."
sees a wide range of applications for the ENVIROCOMP process in
areas other than boatbuilding - including automotive applications,
wind turbine blades, flagpoles and refrigerated trailer doors.
ENVIROCOMP group itself has developed a considerable amount of know-how
on sandwich panel technology and thermoplastic composite material
processing - including mould-tool design, processing conditions,
surface finishing, fabric configurations, bonding and joining, and
mechanical properties. It is now keen to encourage wider use of
this technology by organising technology transfer events, seminars
and workshops, and by providing turnkey systems.