Conti, Kordsa hope new tech will change industry

HANOVER, Germany—Setting out to change an industry, especially one that can move as slowly as the tire sector does, can be a daunting task.

But that's what Continental A.G. and Kordsa Technik Teksil A.S. aimed to do when they unveiled in March at the Tire Technology Expo in Hanover that they had developed a sustainable adhesive technology for bonding textile reinforcing materials with rubber compounds.

Dubbed Cokoon, the technology initially is aimed at use in tire cord materials, but also could have uses in such mechanical rubber goods as hoses and conveyor belts, officials of the two firms said.

Conti and Kordsa are touting the development as a potential new standard in the tire industry, claiming that it eliminates the need for resorcinol and formaldehyde—two materials used in the dipping process used to treat the cords. Those two materials, in a combination some call the RFL glue, have been the industry standard for more than 80 years as the adhesive agent for reinforcing materials.

To try to establish Cokoon as the replacement standard for RFL, Conti and Kordsa, one of the global leaders in the tire reinforcement sector, are offering the development as an "open source" technology. With this concept, other tire makers and suppliers can access the bonding system technology without paying licensing fees as long as those companies in turn agree to make their patents concerning further advancement of the technology available to other partners free of charge via a licensing pool.

"What we are saying is come together and let's have a pool and let's supply an environmentally friendly solution together," said Devrim Oezaydin, global technology director of Izmit, Turkey-based Kordsa. "We can share improvements with all the parties together and we can transform the industry to a better and environmentally friendly world."

And thus far the idea is getting a good share of attention. Within weeks of the March announcement, the partners sent out non-disclosure agreements to more than 25 interested parties, Burak Ilgun, Kordsa market development manager, said in a joint presentation with Conti at the Future Tire Conference, held June 11-12 in Cologne, Germany.

Those seeking information on the technology and the open source platform included tire manufacturers, textile suppliers, converters and materials research groups, Ilgun said.

The need for change

Just getting to this point with a potential game changing technology in the tire industry where secrets are well-guarded and sharing is rare has been a long road.

The resorcinol, formaldehyde and latex dipping solution is a well-established technology that every tire maker and numerous technical goods makers have used for decades, according to Andreas Topp, Conti vice president of material and process development and industrialization.

"It's a technology that works so well that it has been established and has been the standard everybody is using to make sure the bond between the textile cords and the rubber is solid and robust throughout the tire's life," Topp said in an interview at Conti headquarters in Hanover.

But a change is needed because he said resorcinol and formaldehyde are two chemicals that the industry have been looking to replace from an environmental and health point of view. Formaldehyde, in fact, has been described since 2011 by the U.S. National Toxicology Program as "known to be a human carcinogen."

Topp said the issue isn't a matter that impacts end users because once the tire cords go through the vulcanization process the resorcinol and formaldehyde can't escape into the environment. Where it is an issue is in the converting process where the cord is dipped in the solution that has the adhesion promoter, and then it's heat-treated to be ready for embedding in the rubber.

"For that process, those chemicals are used, and we as an industry for many years have been looking for an alternative," he said. "It's not only Continental and Kordsa. Many tire and textile makers are looking for alternatives."

There were three presentations on the topic alone during the Tire Technology Expo in March, including one from Michelin.

The French tire maker in 2018 launched its own high-performance resin adhesive designed for bonding textiles. Michelin created a business unit called ResiCare for commercialization of the resin, which uses polyphenols with antioxidant properties, and polyaldehydes. The ResiCare website said the technology was the product of 10 years of research and development that led to 250 patents. Michelin said it produced 30,000 tires in 2018 using the ResiCare bonded cords.

Topp said there has been many proposed solutions in the past 10 years, but none really got to the serious stage. "The reason why is it's an industry standard and this conversion step is involving quite a sizable apparatus," he said.

There also is a large volume of materials that go through the process in a short period of time. For a converting operation to run the standard RFL step, then change over to a use a new system, would prove too costly, and why a new standard is the best option, according to Topp.

Conti and Kordsa teamed up to tackle the issue—they revealed in 2017 they were working together on the project—because both are invested in coming up with a solution, he said. And they are pushing it as a new standard because the belief is that other industry stakeholders developing "single islands" of their own proprietary solution isn't feasible in this situation.

"We want to have a single standard," said Mustafa Yasin Sen, Kordsa project leader for global technology. "Many companies have their own RF-free formulation, and it takes forever to get approval. Our idea is to have a single standard to replace RF."

Open platform option

Topp wasn't at liberty to discuss the chemicals used in the Cokoon system, but said the system runs on a similar principle as RFL. It uses resins and a latex solution and runs on the same equipment, with just some minor adjustments needed. The chemicals all are readily available from multiple suppliers, he added.

"We are currently at the level where we have seen in our runs that you can basically do it with the same equipment, with only minor changes," he said. "We see no block from the processing and processability (standpoint)."

More importantly, the results in both the laboratory and in tire production have shown they equal the traditional RFL know-how. "We have those results for polyester, nylon and rayon, all the different cord materials," Topp said. "We are working on something from the mechanism of the adhesion that is very similar to what we have today because we believe this makes it much easier to change."

The most common applications will be for car and light truck tires, he said, and Continental plans to produce tires using the technology for sale on the market by the end of 2019. While it is anticipated Cokoon will have uses in hose and belts, Topp said there have been no tests on those products yet.

Conti and Kordsa said they filed several related patents on the technology just prior to their announcement. Now they are sending out samples of the dipped fabric to the interested parties for evaluation.

"If this is to be a new standard, it needs to work not only with our compounds, it also has to work with the compounds of the competition," Topp said. "The only way to evaluate this situation is by handing over the very same sample from the same lot production to manufacturers to evaluate based on their technologies, test methods and experience level."

The two partners worked for several years on getting a system that would work, and then more time focused on how it could become a potential new industry standard.

That is where the open source proposal comes into play. Officials said neither Conti or Kordsa would be able to operate a patent pool with competitors, so that part of the equation is being handled by Advinno GmbH, a Lubeck, Germany-based law firm.

Neither of the principals would be making any money off the arrangement because they aren't producing the chemicals, and the process itself is not a value-added step but one focused on environment and health benefits. Officials said that is why it makes perfect sense for an industry standard shared by all.

"It's a big change but I do believe that we can transform the industry like that," Kordsa's Oezaydin said. "For this environmentally friendly solution they should think differently. Individual solutions cannot be the right solutions. That's why we want them to be part of this team together."

Topp said he knows the tire industry can be slow to change, but there are reasons for that because of the tire's status as a safety product. "There's a good reason we are slow and we have a very thorough way to release new technologies," he said.

On the other hand, he also has seen examples of the industry working with a new dynamic the past five to 10 years, with players having more flexibility and willingness to adapt new technologies.

He also has seen many new people coming into the tire business with a new attitude.

"There's no good reason that it not work, because there are good arguments technically," the Conti VP said. "It's a non-profit approach, so nobody can lose money and nobody can win money. But we can improve the footprint of the tire industry, which is relevant for our customer base and for all the stakeholders and for the people who are working for the industry."