Hanover, Germany — Continental AG and Turkey's Kordsa Teknik Tekstil AS are pleased with the progress of their sustainable adhesive technology and still feel confident they can make their Cokoon-brand dip technology into an industry standard.
Since Hanover-based Conti and Kordsa, one of the global leaders in the tire reinforcement sector, detailed plans in early 2019 to offer Cokoon as a license-free, "open source" technology, more than 70 firms have expressed interest.
Some 24 have signed non-disclosure agreements to receive detailed information about the newly developed know-how; those sampling Cokoon have given positive feedback after testing; and Continental itself has started tire series production using Cokoon.
"We are even more convinced that our target (to be the industry standard) is the right thing to do, and the concept to change over the tire industry and maybe the technical rubber goods industry to this eco-friendly dip solution is just the right target," Andreas Topp, Continental vice president of material and process development and industrialization tires, said.
He discussed the progress of Cokoon in an interview with Rubber & Plastics News, along with Devrim Ozaydin, Kordsa director of global technology, and Bjorn Joachim, managing director of Advinno GmbH, the firm that is administering the licensing pool.
Ozaydin said the 70 companies that have expressed interest include a mix of tire manufacturers, converters, textile suppliers and mechanical rubber goods producers.
"Feedback has been quite positive," he said. "The sample process was a big success and I think exceeded our expectations."
Conti and Kordsa have worked together since 2017 on what became Cokoon, a technology they said eliminates the need for resorcinol and formaldehyde in the dipping process to treat the tire cords.
The two materials have been part of a combination commonly known as the RFL glue — with latex as the "L" — that have been the industry standard for 80-plus years as the adhesive agent in the bonding activation of textile reinforcing materials to the surrounding rubber matrix.
The textile reinforcing materials mainly are used in tire manufacturing, but also are used to produce mechanical rubber goods such as hoses and conveyor belts.
In recent years there has been an emphasis — and much research — on replacing resorcinol and formaldehyde from an environmental and health point of view.
Both Conti and Kordsa emphasize that workers in tire plants and end consumers aren't exposed to the substances because they are chemically altered through the vulcanisation process.
Where it is an issue is in the converting process where the tire cord is dipped in the solution that has the adhesion promoter, and then is heat-treated to be ready for embedding into the rubber.
The partners claim their Cokoon technology can do just as good a job without using the RFL combination, relying on readily available materials, including epoxy, block isocyanates, latex and some other additives, according to Ozaydin.
They also said the process uses the exact same machinery as RFL, doesn't require any additional processing steps and can be done for the same cost.
Continental and Kordsa also said that, in an effort to get the industry to accept Cokoon as the industry standard, they felt it was necessary to offer it as an open innovation technology.
Under this setup, outside parties can join the licensing pool and use the new dip technology without paying development or licensing fees. In return, licensees would be expected to make their patents concerning further enhancement of the technology available to other pool members free of charge.
After receiving positive feedback from the industry, Conti started the integration of Cokoon into series tire production in late 2019, and had planned to expand that this year to produce up to 250,000 passenger tires featuring the sustainable adhesive technology, Topp said.
However, like all tire makers, Conti has had to cut back on tire production for a good portion of 2020, due to the COVID-19 pandemic. As a result, Conti hasn't made as many tires as expected with Cokoon this year. But the firm has been pleased with its performance thus far.
"We are happy with the performance and processability," Mr. Topp said. "Everything seems to be just fine as expected on the tire side, and also on the R&D side to further develop the technology for other applications."
Continental is using Cokoon at one of its tire factories, but the Conti official wouldn't identify which one.
"It's a starting point," he said. "That means we are running one production plant, and we are extending at the end to worldwide production because we want to translate the whole production in the area of textile cord dip to this new technology."
Progress also is being made in terms of setting up the licensing pool, according to Advinno's Joachim. His firm is handling all requests from interested parties, and in that role he said it plays no favourites.
Different colours can be applied on textiles while using the new eco-friendly dip technology Cokoon.
"When it comes to the pool, Conti and Kordsa are equal as each pool member is," Joachim said. "They have no special benefits and no special obligations, so all parties are the same."
There was some delay in being able to deal with potential partners this year, because the annual Tire Technology Expo took place at the end of February, right before the coronavirus shut down much industry around the globe. That pretty much tabled all feedback and discussions until the end of April or early May.
Still, Joachim is pleased with the 24 companies that have signed NDAs as they evaluate Cokoon, noting that there are interested parties from all regions of the world except for Australia. Two-thirds of those interested are converters that produce the dip and apply it to the cords, and one-third are manufacturers, mainly tire producers but also a couple from mechanical rubber products.
A third company already has joined Conti and Kordsa as pool members, he said, and two other parties have agreed to enter the pool, with paperwork for them expected to be completed during September.
In addition, one new patent family has been added to the pool in addition to the eight patent families Conti and Kordsa contributed when setting up the open source platform.
"I think it's very good progress, especially taking into account the current situation," said Joachim, addingthat interested parties so far say they understand the legal concept behind it and are fine with the provisions.
It also can be a task to develop agreements that have to cover small and large companies, prospective members that have intellectual property they may want to add, as well as firms that don't have IP and only want to take a license.
Topp said he too is pleased with the progress: "Our area of the industry is not known for being the most flexible when it comes to legal situations, and I include my company.
"That we have one pool member that is already in the process of contributing its own IP to the pool, to me that is very much surprising.
“I'm very optimistic that that's a good sign that this concept, once it's digested and understood and accepted, that for this part of the industry makes real sense."
Becoming a standard
Of course, getting positive feedback is a long way from replacing a standard that has been in place for more than eight decades. But both Topp and Ozaydin said their companies are willing to be patient.
The Kordsa official said one point to emphasize is that the aim from the start has been to make the technology available to the entire industry.
"Everyone can be a part of this open innovation platform," Ozaydin said. "Join the pool and get free licensing and contribute to the new open technology, and we can transfer the whole industry over to this Cokoon technology."
Topp said he is even more convinced it is the right thing to do.
"Technically it fits. The legal framework and the concept, it fits," he said. "I'm really happy we started together with Kordsa on this journey and we continue to go forward.
He said the time frame won't be short, and that Continental likely will be the first tire maker to be fully converted. "Every company will do a very careful process in converting its portfolio to the new technology, so we are talking about years," Topp said. "We can't really say for certain. It will keep us busy for some time."
Even with other competitive technologies on the market — including one Michelin has been working on for years — the partners believe theirs has several advantages.
Ozaydin said potential users shouldn't overlook that it can be used with current machinery and there are many suppliers for chemicals.
And Topp said while Cokoon was met by skepticism when first introduced, the more people understand it, the more potential he sees for it to make inroads in the market.
"With all the arguments, the technology works, it doesn't take changes in the process and it doesn't take additional cost for the material itself," he said. "And it works across, so far, all the industry tests in a positive way. It's hard to beat."