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REIFEN ESSEN
Kraiburg – Electric Rubber
Kraiburg is one of the partners in BIPAVER’s ReTYre scheme to establish a process for the homologation of retread tyres and there is rather obviously a sense of uncertainty in the air when talking to the management. “Of course,” says Holger Dux, “we hope that there will be a solution found but if not, then who knows what will happen to the retread sector in Europe.”
However, on a more positive front, Kraiburg has invested in research and development into how OTR retreading can be made more cost effective using the pre- cure method called K_Inno.
Currently the process requires heating the whole tyre to around 110 degrees to vulcanise the bonding process and create a retreaded OTR tyre. This is traditionally done in an autoclave that uses considerable energy and time to cure a whole tyre. Kraiburg’s R&D team thought, what if we only heated the elements that needed curing? If the cushion gum was heated to curing point and held for a period to allow the bonding to take place, then there was the potential to save a great deal of time, energy and money.
The concept of heating just the cushion gum is not new and one process uses thin wires embedded in the camelback to heat the bonding area and Hawkinson’s process for truck tyres heats only the cushion gum. However, Kraiburg have developed a conductive cushion gum that heats by Ohmic resistance.
Kraiburg’s Dieter Hasenkopf explained the process, showing how savings in time, energy and costs could be made if the process were developed for OTR tyres. Rather obviously a large OTR tyre retreaded by either hot cure or traditional precure method takes a long time to heat to the required vulcanisation temperature, measured in hours rather than minutes. Kraiburg’s new process by heading the conductive rubber reaches vulcanising temperature in minutes, in fact, on the demonstration piece it reached operational temperature for vulcanising in about 6-8 minutes. The proof of the process being that although the infra red temperature sensor was reading over 86 degrees, the sidewall and tread blocks of the tyre were cold, or at best warm.
The tyres still need to be processed under vacuum pressure in an autoclave, but there is no need to heat the whole autoclave just the bonding gum and the adjacent mating surfaces.
Kraiburg is now looking for partners to develop the process for production and take it out to the market. There is a strong belief that the savings will attract both partners and clients interested in utilising the process.
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arbrasive
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2000 Trichy Road Coimbatore 641 005
Tel : +91 422 232 1000 Fax : +91 422 232 2222 E-mail : info@in.elgirubber.com www.elgirubber.com
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