Polymer producers have responded to the changing tyre industry expectations, their innovations take into account a more reactive functionality within polymer architecture, and this is closely matched by increasingly greater degrees of filler surface chemistry. As a result, tyre compound properties may now be tailored to meet quite specific tyre performance targets.

Tyre processing methods also underwent progressive stages of modernisation in recent years, for example, more sophisticated reactive mixing technology together with high-speed extrusion systems allowing for direct extrusion onto the building drum become established as cost effective production routes for many of the major producers.

These advancements however bring about their own conflicts, processing pathways involving multiple stages, often with the ability to rework compound or adjust rheological properties by additional time or energy input during the process are no longer viable options for most tyre producers. It has thus become necessary to achieve processability through an increasingly narrow operating window.

Formulations optimised to achieve peak tyre performance in most cases also tend towards more challenging processing characteristics. This is to be expected; the use of high and narrow molecular weight reactive polymers alongside fillers having high surface area and chemistry, often in loadings above that of the polymer are the norm. The trend towards usage of high loading of plasticiser and resinous materials to adjust tyre tread grip and traction response all contribute to a less forgiving processing nature. Often those compounds that are highly reinforced appear the most fragile during processing and poor green strength with an easily tearing or crumbly compound appearance are often-discussed processability issues. By contrast, the use of high loadings of resins and plasticisers, for example in winter or high-performance tyre formulations, results in compounds that during processing can more resemble chewing gum than tyre treads!

The use of process additive chemicals in an attempt to overcome the processing limitations observed gives rise to further conflicts; Lubricant additives might improve compound surface appearance; however, green strength will probably further reduce due to the unwanted softening effect. The same is true for release additives where lower tack unfortunately remains at a higher value than the also lowered tensile strength of the compound. Filler dispersion is often targeted by additives, however higher loading of fillers mandate equally higher additive loadings, we should more accurately discuss loading as “parts per hundred of filler” not rubber, and under the appropriately higher additive loading, the risk of interference with vulcanisation properties or even additive migration leading to surface bloom become realistic concerns.

Conflicting performance characteristics

The development team at Schill + Seilacher has recognised the need to decouple conflicting performance characteristics found within conventional process additive chemistries. As a result, innovation within our Struktol® range offers tyre compounders opportunities to achieve processability without compromise.

Reduced viscosity leading to better extruder flow properties and improved surface appearance, whilst at the same time achieving an increased compound green strength can be realised by use of Struktol HT 300, a new generation of reactive process additive.

An extract of key processing and property influence in a typical highly silica filled sSBR tread compound are highlighted in the following data.

Significantly lowered Mooney viscosity as well as better mixer batch off with reduced sticking to the mixer rotor and gate with Struktol HT 300 are observed.

An increase in compound green strength was obtained by the addition of Struktol HT 300; this is the opposite of expectation for conventional process additive chemistry, where reduced viscosity is obtained. In addition, the filler dispersion as evidenced by a reduction in the so-called “Payne Effect” as tested in uncured compound by means of RPA strain sweep, is also improved.

Lab extrusion trials, using cold feed extruder demonstrate improved surface appearance and lower compound pressure achieved by use of Struktol HT 300, both desirable processing conditions.      

Physical properties are also acceptable, with a progressive increase in tensile strength an elongation and maintenance of stiffness with loading of 6 phr of process additive, only at higher loading of 12 phr would a balancing slight reduction in process oil be required.

Compound hardness remained unchanged alongside improved wear resistance, as measured by DIN abrasion loss testing, even when using higher loading of process additive, are important aspects.

The ability to decouple the relationship between lubrication, important for improved rheological behaviour, and the maintenance of strength and stiffness in both the uncured and vulcanised condition is only possible with such new and innovative class of process additive. This departure from conventional thinking offers the tyre compounder significant degree of freedom to retain the benefits in terms of easier processability without sacrifice of key tyre performance properties.

In this example, the use of Struktol HT 300 prioritised green strength alongside reduced viscosity. By contrast, our new Struktol HT 250 decouples release from other properties, especially effective for winter tyre tread; compound stickiness is resolved without compromise of viscoelasticity.

Ensuring that migration and ultimately bloom within rubber compounds is kept to the lowest level is important for final article aesthetics, for tyres additional considerations arise; they are composite structures, therefore it is imperative that chemicals do not migrate across boundary layers in an uncontrolled manner, which could result in changed behaviour or interfacial adhesion failure over time. In order to limit migration, the compatibility, solubility and concentration of chemicals are carefully considered. However, one method of ensuring long-term stability involves chemically binding the additive within the vulcanisation network.

At Schill + Seilacher, we have achieved this degree of crosslinking capability for a number of new-generation Struktol process additives. Their usage allows the compounder to avoid completely the risk of migration and bloom due to additive presence.

Photographs of two vulcanised rubber sheets based on the same formulation. On the left-hand side, evidence of typical surface bloom, which may occur due to migration of a conventional process additive, on the right, containing reactive additive Struktol HT 600 as replacement, it can be seen that bloom was eliminated.

This technology also opens tremendous opportunities to “fix” process additives in place within the respective component, the role of additives withinthe cross-linking mechanism may additionally lead to vulcanisate performance characteristics.

                                                                                  One interesting tyre related example involves the development of a superior tyre curing bladder performance, here we have developed new reactive plasticisers called Struktol HT 815 and Struktol HT 820, their use is directed towards resin-cured butyl rubber. This combination of polymer and curing system provides for superior heat resistance with excellent flex fatigue resistance and is used as the basis for tyre curing bladders. Here the replacement of widely used castor oil as plasticiser with new Struktol HT 800 series product leads to a significantly improved bladder performance life, with greater stability in viscoelastic properties. Reduced stiffening of the bladder, due to lower degree of plasticiser migration translated into a much lower flex-cracking rate, especially after high temperature steam ageing.

Reactive Struktol plasticisers, HT 815 and HT 820 exhibit a significantly reduced flex cracking rate when compared to the widely used castor oil, which readily migrates from the bladder; as a result, significant extension of bladder service life is possible.

New reactive process additives, with tailored functionality to closely match the specific chemistry of polymers, fillers and cure systems are actively developed. These innovative products under the Struktol brand offer tyre compounders a more comprehensive toolkit in order to tailor compound performance to meet tyre performance demands. The conflicts of property versus processability diminish and new possibilities emerge!

Pyrum Innovations AG is all set to commence construction on a tyre pyrolysis plant in Vřesová, the Czech Republic, in partnership with the SUAS GROUP and Sokolovská uhelná. The construction work will start in the second quarter of 2025 and the completion is targeted for 2027.

Pyrum and SUAS GROUP will establish a joint venture for the joint construction and operation of the plant. Pyrum will purchase a 49 percent share in the business. Existing loan framework agreements cover Pyrum's stake in the project. The Czech businesses intend to incorporate the gas generated during thermolysis into the current plant for further use and to take use of the synergy effects on site. Each year, 23,000 tonnes of end-of-life tyres will be transformed into useful materials by the proposed operation. An estimated EUR 57 million will be invested in the project.

Martin Čermák, Board Member of SUAS GROUP and Sokolovská uhelná, said, “We are among the first companies in the world to utilise this innovative technology within our industrial complex in Vřesová. The site has the necessary infrastructure not only for the facility’s construction but also for utilising the gas produced during pyrolysis, which is rich in hydrogen and methane. The technology is extremely environmentally friendly, as confirmed by the recently completed Environmental Impact Assessment (EIA). Among other benefits, the project as a whole, significantly reduces the carbon footprint – by more than 18,000 tonnes of CO₂ annually.”

David Najvar, Chairman of the Board of SUAS GROUP, said, “We greatly appreciate that Pyrum Innovations AG, the holder of this revolutionary patent with experience in similar projects across the EU, has become our partner. Together, we are fulfilling the vision of developing a circular economy and sustainability in handling specific types of waste and their disposal within our region and the Czech Republic.”

Pascal Klein, CEO, Pyrum Innovations AG, said, “The collaboration with the SUAS GROUP represents further progress for the development of the circular economy in Europe. This project demonstrates the high adaptability of our technology. Thanks to the efficient use of the gas on site, the end-of-life tyres can be almost completely recycled. Even though each site has individual potentials and designs, the core of our technology remains constant. We are looking forward on a very successful partnership and to the next phase of our collaboration, realising the joint plant at the new site.”

Orion S.A., a global speciality chemicals company, has been recognised as a ‘Key Innovator’ by the European Commission's 'Innovation Radar’ website, which identifies high-potential innovators that have done EU-funded research, for being the first company to produce circular carbon black from 100 percent pyrolysis oil from end-of-life tyres.

The circular carbon black was created by Orion as a collaborator on the EU-funded BlackCycle project (Horizon 2020 programme under grant agreement No: 869625). The material is ready for the market as a substitute to carbon black derived from fossil fuels. The goal of the Michelin-led, award-winning BlackCycle effort was to develop innovative methods for creating new tyres from used tyres. It involved five research and technology organisations as well as seven industry partners.

Last year, Orion also started its ‘Clean Carbon Black Research and Development Project’, which was made possible by a EUR 6.4 million funding from the European Union and the German Government. The goal of the project is to create a method for making carbon black from alternative carbon sources that is climate neutral.

Corning Painter, CEO, Orion, said, “Driving circularity is part of Orion’s long-term strategy. Our customers are increasingly relying on us to provide solutions to meet the growing demand for circular products. We are scaling up our capabilities to process tyre pyrolysis oil and have other innovations in our sustainability pipeline focused on cost-effective solutions.”

Natalia Scherbakoff, CTO, Orion, said, “Although the BlackCycle project has concluded, our innovation work continues with other initiatives with circular carbon black that involve reducing our carbon footprint, improving yield and throughput and potentially lowering material costs.”

The global demand for efficiency and precision in tyre manufacturing has reached unprecedented levels, and VIPO a.s., a pioneer in advanced bead winding technology, has delivered a game-changing solution: the LIHEXAL 8 – octuple head single wire bead winding machine (production of 8 beads per cycle). Designed specifically for the production of PCR (Personal Car Radial) tyres, this latest innovation epitomises cutting-edge research and development, coupled with decades of expertise in rubber and wire applications.

A LEAP FORWARD IN BEAD MANUFACTURING

The LIHEXAL 8 sets a new benchmark for bead winding machines, enabling the simultaneous production of up to eight beads per cycle. This state-of-the-art machine accommodates bead diameters ranging from 13” to 24.5” and cross-sections in both hexagonal and rectangular profiles.

The latest model of VIPO’s bead winding machine significantly reduces production time while maintaining consistent quality. The result is an increased beads output, minimised downtime and improved profitability for tyre manufacturers around the globe.

INNOVATION AT EVERY STEP

The LIHEXAL 8 redefines bead production with cutting-edge sensing and automation technologies. It offers real-time monitoring of material levels and predictive maintenance, ensuring seamless operations. Precision is at its core, measuring key variables like wire temperature, rubberisation and other parameters to guarantee beads of impeccable quality. Its advanced festooner system with independent pulleys allows precise control of wire tension and pressure, adapting effortlessly to unique production needs. Meanwhile, the upgraded bead winding station delivers unparalleled accuracy and speed, producing one bead every two seconds with flawless consistency.

VIPO’s innovations go beyond speed – they deliver reliability. With every cycle, manufacturers achieve premium-quality beads, securing their competitive advantage in the tyre industry.

GROUNDBREAKING WRAPPING TECHNOLOGY

One of the most notable features of the LIHEXAL 8 is its integrated bead wrapping system. In collaboration with the world’s best wrapping tapes suppliers, VIPO has developed a high-performance wrapping solution that applies tape to bead ends simultaneously without affecting the machine’s cycle time. With a machine autonomy and real-time verification of tape application, this system guarantees optimal quality and consistency.

A LEGACY OF EXCELLENCE

Rooted in the legacy of Tomáš Bata’s historic town, VIPO a.s. has been at the forefront of rubber and wire technology for over 50 years. Combining generational expertise with cutting-edge innovation, VIPO proudly serves the world’s leading tyre manufacturers – partners who trust its solutions to deliver excellence. This enduring trust drives VIPO to continuously push the boundaries of innovation, with gratitude to its customers as the foundation of its success.

EXCEPTIONAL SERVICE, UNMATCHED RELIABILITY

From installation and training to continuous support and machine optimisation, VIPO ensures that clients harness the full potential of the LIHEXAL 8. This exceptional level of service, combined with the machine’s unparalleled performance, makes it a cornerstone for modern, efficient and premium tyre manufacturing. Moreover, the LIHEXAL 8’s unmatched reliability and advanced automation significantly reduce human intervention, paving the way for streamlined operations and optimised production workflows.

WHY EVERY TYRE MANUFACTURER NEEDS THE LIHEXAL 8

The LIHEXAL 8 isn’t just a machine – it’s a revolution in tyre manufacturing. With precision, flexibility and speed, it meets the demand for high-quality beads while driving down costs and enhancing efficiency. Designed to adapt to each customer’s unique needs, it’s the ultimate solution for modern production challenges.

More than a supplier, VIPO is the trusted partner and committed to its clients’ success. The LIHEXAL 8, as well as the other VIPO equipment and services isn’t just about transforming production – it’s about empowering your business to lead in a competitive market.

CarbonX has been selected for the European Innovation Council (EIC) Accelerator grant. The allocated funding includes a EUR 2.5 million grant and EUR 5 million equity package to accelerate product development and market expansion.

In the most competitive funding round to date, CarbonX was selected from 71 top firms out of 1,211 submissions. This accomplishment demonstrates CarbonX's state-of-the-art technology, commercial maturity and dedication to sustainability. It also represents a major turning point in the company's goal to transform the supply of active anode materials in Europe, thereby solidifying its role in replacing graphite in Europe within the automotive battery green technology sector.

Rutger van Raalten, CEO, CarbonX, said, “I am very proud of this accomplishment, successfully coming through a tough application process and completing rigorous due diligence – this is great validation of our technology and demonstrates a complete product offering at the right price. With support of the EIC, we will accelerate the realisation of a fully independent European supply chain for critical battery materials.”