old tyres by retreading is an established technique. By buying retreads,
drivers can help prevent scrap tyres from ending up in landfills and on
illegal dumps. In the EU, only 12% of all car and truck tyres are currently
retreaded and reused. Thanks to a CRAFT project which aimed to improve
the quality control and performance of retreaded tyres made by SMEs, new
inspection and testing equipment has been developed, along with environmentally
friendly water-based adhesives to replace organic solvent-borne formulations.
Such innovations in monitoring quality will lead to economical and environmental
benefits in a European market worth € 1 billion.
equipment for improving the reliability of retreaded tyres has just won
its first customer. Such equipment was just one development resulting
from a CRAFT project that aimed to help SMEs improve their retreading
business by providing a better quality control.
of retreading involving recycling a tyre by removing a worn tread and
replacing it with a new one, allows tyres to be reused. While a car tyre
may be retreaded only once, lorry tyres are often retreaded two or three
times, and aircraft tyres many times.
are highly recyclable
are many millions of tyres made each year in Europe and every year,
at the end of their useful life of a few years, over 250 million
are thrown away. But tyres can be recycled. The main problem is
economic: recycling costs more than dumping, so many tyres end up
in landfills or on illegal dumps, adding to those already polluting
the landscape. Tyre dumps are potentially dangerous: they can catch
fire, and when they do, toxic chemicals are released, leaving an
oily residue that can contaminate groundwater.
only about 12% of the EU's scrap tyres are retreaded and reused,
so a long-term goal of the project was to help boost this level
by increasing consumer confidence in the reliability of retreads.
project co-ordinator is Dr Alan Roberts, deputy director of the
Tun Abdul Razak
Research Centre, the British arm of a Malaysian rubber research
organisation. John O'Connell used to work for the organisation in
Malaysia before starting up his own company, Bandvulc Remoulds,
a UK SME retreader based in Devon. Dr Roberts and his colleagues,
with their wealth of experience in retreading research, were in
contact with many SME retreaders. He knew about CRAFT projects and
Mr O'Connell knew about making retreads. They both recognised the
need for tyre retreading to become as scientific and technological
as possible. Together they began to form the project consortium.
award was granted to evaluate the proposal before it was accepted
as a two-year CRAFT
project, which addressed the three major technical issues in retreading
modern tyres are usually reinforced with steel cord and over time,
water can penetrate into the tyre and rust the cord. The retreader
has to examine the tyre to see if any corrosion has already developed.
To reach the cord the old tread has to be removed by being ground
away. To minimise inspection costs, a non-destructive test was needed
to indicate quickly whether a tyre should be accepted or rejected
before this process.
depending on the retreading process employed, a cement or adhesive
may be needed to stick the new tread to the old tyre. Current cements
use potentially harmful organic solvents, which must be replaced
Finally, since the tread rubber is in contact with the road, this
is normally the only part of the tyre to wear away. The service
life of the retread thus depends mainly on the wear or abrasion
resistance of the new tread. Retreaders must be able to guarantee
the service life (in kilometres) of their products. To do this,
they need a new abrasion tester capable of predicting tread wear
and tyre life under service conditions.
final consortium comprised 21 partners: 11 SME car and truck retreaders,
two SME test equipment or instrument manufacturers, five large raw
material suppliers, and three research organisations. It included
not just SMEs but also large companies such Bekaert,
the world leader for manufacturing steel cord for reinforcing tyres;
a global supplier of carbon black (which is used to improve the
wear resistance of rubber treads); and Gummiwerk
Kraiburg, a leading rubber products manufacturer.
project team also benefited from a technology transfer from the
German steel industry to the European rubber field. The RWTH
Technical University of Aachen provided expertise in tyre wear
to design the new abrasion test method, and detecting surface corrosion
of steel pipes to develop a electromagnetic device to check tyre
cords for rust.
team met all their objectives. The first rust detector is now operational
- manufactured by one project partner and bought by another. The
used tyre is checked for its suitability for retreading in less
than 10 seconds. It is spun round once in front of the electromagnetic
detector and either gets a green light for 'go' or a red light for
'no go' if rust is detected. Water-based cements are now being used
in production and the new abrasion tester is now ready for commercialisation.
monitoring of retreads will increase the reliability of the life
of retreaded tyres. It will lead to clear economical and environmental
benefits. An important project spin-off is the ongoing co-operation
between the partners, who are now behaving as a 'network'. Along
with new members, they are already working on a new CRAFT project.
Each percentage increase in the market share of re-used tyres represents
potential annual Europe-wide sales of an estimated € 100 million
for the retreaders.