HANOVER, Germany — Continental A.G. and Kordsa Tecknik Tekstil A.S. have developed a sustainable adhesive technology standard for bonding textile reinforcing materials with rubber compounds that they claim eliminates the need for resorcinol and formaldehyde.
The companies disclosed their development at Tire Technology Expo 2019, a trade show and conference in Hanover that runs through March 7.
The partners, which disclosed in mid-2017 they were working on such a solution, said they are offering the new bonding system technology to other interested parties as an "open-source," no-cost solution under the brand name "Cokoon."
Separately, Continental said it plans to have series-produced tires using this technology on the market this year, although it did not specify which tires would be first.
For decades, the chemicals resorcinol and formaldehyde have been irreplaceable in the bonding activation of textile-reinforcing materials to ensure robust adhesion to the surrounding rubber matrix, Conti and Kordsa said in a joint statement.
Resorcinol — a phenol derivative chemically known as 1,3-dihydroxybenzene — has been used since the 1950s to improve the adhesion of organic and inorganic reinforcing materials to natural/synthetic rubber compositions.
Formaldehyde is a naturally occurring organic compound — CH2O (H-CHO) — that is used widely as a precursor to many other materials and chemical compounds. The U.S. National Toxicology Program described formaldehyde in 2011 as "known to be a human carcinogen."
These substances are chemically altered by the vulcanization process, so they do not escape from the finished products into the environment.
With Cokoon dip technology, they said, the bonding of textiles to rubber is now possible without these two substances and can be applied without changing process equipment.
The partners have posted a short video on YouTube to explain the process.
"We need to break new ground to master the upcoming challenges the future will hold," Andreas Topp, vice president material and process development and industrialization at Continental, said.
"The tire industry can send out a clear signal of its responsibility and innovative power by joining to this environmentally friendly open-source technology," Devrim Özaydin, Kordsa's global technology director, added. "We are working continuously to introduce more environmentally friendly products in the interests of our employees, society and the environment."
Continental and Kordsa have chosen to waive development or licensing fees. In return, they said they expect licensees to make their patents concerning the further enhancement of this technology available to the other partners free of charge via a licensing pool. Interested companies can request first lab samples now.
They have designated AdvInno G.m.b.H., a Lubeck, Germany-based law firm, to handle licensing arrangements.
Izmit, Turkey-based Kordsa, founded in 1973 by Sabanci Holdings, is considered a global leader in reinforcing textiles. It claims to be the supplier for half the world's car tires and two-thirds of aircraft tires.
Last year Group Michelin disclosed the development of its own alternative to resorcinol-based adhesive techology with a high-performance resin adhesive that uses polyphenols, with antioxidant properties, and polyaldehydes, regularly used in the perfume industry, to replace the resorcinol and formaldehyde in the adhesive.
At that time, Michelin said it expected to have some tire lines in production by year-end 2018 using the new technology.
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