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!

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Kraton Corporation, a leading global producer of speciality polymers and high-value bio-based chemicals derived from pine wood pulping co-products, has announced a price increase of USD 220 per metric tonne, equivalent to USD 0.10 per pound, across all polymer products sold in North America. The affected lines include Kraton D SBS, Kraton D SIS and Kraton G SEBS/SEPS.

According to the company, the adjustment is necessary to offset significant and sustained increases in feedstocks, energy, logistics, process materials and other manufacturing costs. The increase will take effect on 1 December 2026 or as permitted by applicable contracts.

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Evonik, a global speciality chemicals company, has completed a EUR 52 million expansion of its silicone platform at the Essen Goldschmidtstrasse site in Germany, constructing a new production plant and a large tank farm. The facility raises output capacity for organomodified silicones, a core product group in the company’s global silicone network.

The Essen site operates as a central node in that network, closely tied to Evonik facilities in Geesthacht, Obernburg and Wittenburg in Germany, Pandino in Italy, Shanghai in China and Hopewell, Virginia, in the United States. The expansion strengthens the resilience of this international production system by lessening the need to ship intermediates and finished goods between locations.

Logistics infrastructure has been optimised to support more efficient operations. A new 150-metre pipe bridge links four production units and 15 manufacturing assets to the tank farm, which comprises five stainless-steel tanks, the tallest standing 24 metere and holding substantial quantities of key raw materials. The result is steadier production, more robust supply chains and reduced reliance on short-term deliveries. The tank farm has enlarged the Essen site from 32 to 35 hectares.

The project was executed with the site fully operational and despite constrained space, drawing on roughly 80 Evonik employees and over 230 contractors from 25 partner companies. Essen Goldschmidtstrasse also features in Evonik’s newly developed long-term plans, which assign a clear profile to each of six major production sites – Essen Goldschmidtstrasse, Marl, Wesseling, Darmstadt/Weiterstadt, Rheinfelden and Hanau – as guidelines for future development. Under this framework, Essen Goldschmidtstrasse is positioned as a centre of excellence for customer-specific formulations.

Lauren Kjeldsen, the Evonik Management Board member responsible for the Custom Solutions segment, to which the business belongs, said, “This expansion strengthens our silicone production platform, enhancing supply chain resilience and creating a strong foundation for profitable growth. This latest investment highlights the important role that our innovative German sites play in the success of our global operations.”

Roberto VilaKeller, head of the responsible Business Line Interface & Polyurethane Additives, said, “The investment in Essen strengthens our global production network and further enhances our ability to serve customers reliably around the world. It significantly expands our production capabilities, reduces potential bottlenecks and creates opportunities for future growth in attractive markets.”

Thomas Kufen, Mayor of Essen, said, “At a time when industrial investment is more important than ever, projects of this scale send a strong signal for Essen’s economy and the wider region. They secure high-quality jobs, strengthen competitiveness and demonstrate the international attractiveness of our city as an industrial hub.”

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The Association of Natural Rubber Producing Countries (ANRPC) has published its Monthly Natural Rubber Statistical Report for September 2026, a month marked by broad-based price gains. Firm fundamentals, constrained supply and steady downstream demand combined with geopolitical and macroeconomic uncertainty to lift prices. Renewed Middle East conflict and disruptions to major shipping routes weighed on sentiment, while energy markets were especially affected by the closure of the Strait of Hormuz and attacks on transiting vessels, which raised risks to global energy supplies and strengthened the crude oil risk premium.

According to the report, physical prices for most major grades advanced. SMR-20 in Kuala Lumpur averaged USD 2.50/kg, up 7.96 percent month-on-month, and STR-20 in Bangkok rose 5.80 percent to USD 2.53/kg. RSS-3 in Bangkok slipped 0.30 percent to USD 2.79/kg, while RSS-4 in Kottayam eased 1.39 percent to USD 2.88/kg. Latex-in-bulk in Malaysia gained 3.60 percent to average USD 1.79/kg. Cautious tyre-manufacturer purchasing, limited to immediate needs after earlier increases, weighed on the RSS market. Latex drew support from tight supply, as persistent rainfall disrupted tapping and limited fresh and concentrated latex availability, while glove, healthcare and industrial demand held stable.

Trade flows diverged. China's imports grew 2.56 percent month-on-month, India's 11.36 percent and Malaysia's 17.85 percent, whereas Viet Nam's fell 3.40 percent. Exports rose 3.07 percent in Thailand, 7.30 percent in Malaysia and 1.91 percent in Cambodia, while Indonesia edged down 1.40 percent and Viet Nam recorded the steepest decline at 9.72 percent.

Global production is projected at 15.039 million tonnes in 2026, up 0.6 percent from 14.953 million tonnes in 2025, with September output estimated at 1.4 million tonnes. Uneven rainfall and elevated temperatures slowed supply recovery across Southeast Asia. Global demand is forecast to rise 0.4 percent to 15.356 million tonnes from 15.301 million tonnes, with the largest volume increases among ANRPC member countries. Prospects depend on vehicle sales, tyre production, shipping conditions and weather-related disruptions, while expanding electric-vehicle markets in China, India and Europe support modest growth.

The ringgit traded between RM4.04 and RM4.10 per US dollar, and the baht between THB 32.89 and 33.55. The SHFE January 2027 contract averaged CNY 19,070/tonne, up 5.3 percent month-on-month, and the SGX December 2026 contract averaged USD 2.41/kg, up 7.6 percent. Brent crude averaged USD 114.16 per barrel, a 25.3 percent monthly increase driven by geopolitical risks and shipping disruptions through the Strait of Hormuz.

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Birla Carbon, a leading global supplier of carbon materials, will exhibit at the International Rubber Conference (IRC) 2026, scheduled for 2–6 November in Nagoya, Japan, at Booth B. The company aims to address application-specific demands arising from the shift towards electric mobility, which places greater emphasis on tyre wear and energy efficiency while requiring automotive rubber components to balance durability with ride comfort.

A Very High Structure (VHS) lineup awaits manufacturers of passenger car, light truck, truck and bus tyres. These grades were engineered to meet electrification requirements and tightening standards such as Euro 7, delivering gains in tread wear, energy efficiency and tyre longevity.

Sustainability also features prominently. The company's Continua Sustainable Carbonaceous Materials (SCM) and Sustainable Carbon Blacks (SCB) lines, which contain higher levels of recycled or bio-based material, are intended to help tyre makers pursue circularity targets. Their dependable quality and ability to be supplied at scale in large volumes make them viable for production use, and the Continua range carries ISCC PLUS certification.

Mechanical rubber goods round out the display. Grades aimed at bushings enhance mixing and dispersion, contributing to fatigue life and component durability, while formulations for mounts pair low hysteresis and low stiffness with reinforcement so that durable parts can be produced without sacrificing ride comfort. Drop-in grades for extrusion reduce defects, scrap and screen-pack changes while raising throughput and extending service life. Simulation and technical expertise help customers assess materials, and global production plus Asian capacity growth support long-term supply.

Amit Kumar, President – Asia, Birla Carbon, said, “Asia’s tyre and rubber manufacturers are shaping the next phase of mobility, and their material requirements are becoming increasingly stringent. As the clear leader in our industry, Birla Carbon aims to grow alongside our customers, combining application-focused innovation with dependable local supply. We see performance and circularity as priorities that must progress together. By expanding our capabilities in Asia and strengthening customer partnerships, we aim to help manufacturers meet evolving market needs and build greater long-term competitiveness.”

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