• Plastic ( soft or malleable) at normal ambient temperatures
• A melting point above approximately 45 °C.
• A  relatively low viscosity when melted (unlike many plastics)
• Insoluble in water
• Hydrophobic

We shall be discussing here on the waxes which are only being used in the rubber and plastic industry. Beeswax, perhaps , is the first wax which used by human in the beginning of our civilization, was one of the important renewable source of fuel. The honey comb formed by bees has typical hexagonal geometric pattern (Fig.1). Bees wax is used in tire building drum, if the rubber is too sticky, it can also be used in two roll mill to take care of rubber sticking to the rolls. It is frequently being used in the BC, MC, PC, TB  inner-tube making industry during pre-forming operation in the green stage when inner-tubes are expanded under mild air pressure just before curing in mold.

The main commercial source of wax is, however, crude oil but not all crude oil refiners produce wax. "Mineral" wax can also be produced from lignite. Plants, animals and even insects produce materials sold in commerce as "wax". There are five categories of waxes being used in rubber industries :

• Bees Wax
• Paraffin Wax - made of long-chain alkane hydrocarbons
• Microcrystalline Wax - with very fine crystalline structure
• Chlorinated Paraffin Wax
• Polyethylene Wax
• Chlorinated Polyethylene Wax

The major uses of petroleum based waxes are in rubber, cosmetics and in Candle industry. They are generally white in color but show usual brown color (Fig.2) due to contaminated with oil traces. Two types of waxes, in general, are used in rubber industry, Paraffinic wax and Microcrystalline wax. Its normal dose is 1-3 phr and high level of wax impairs low temperature flexibility and compression set. Rubber compounder considers wax as a very important processing aid because it has following advantages:

• Improves mixing properties

  

   

• Improves dispersion of filler and other ingredients
• Improves extrusion properties
• Improves upon extrudate and calendared surface finish
• Protects surface and acts as antioxidant /antiozonate

Paraffin and Microcrystalline waxes are derived from petroleum. They are easy to recover and offer a wide range of physical properties that can often be tailored by refining processes. Most producers offer two distinct types of petroleum waxes: paraffins, which are distinguished by large, well formed crystals; and microcrystallines, which are higher melting waxes with small, irregular crystals. Microcrystalline wax contains substantial proportions of branched and cyclic saturated hydrocarbons in addition to normal alkanes.

Some producers also sell "intermediate" wax, in which the boiling range is cut where the transition in crystal size and structure occur. Petroleum wax producers also characterize wax by degree of refinement; fully refined paraffin has oil content generally less than 0.5% and fully-refined micro-crystalline less than 3%. Paraffin wax produced from petroleum is essentially a pure mixture of normal and iso-alkanes without the esters, acids, etc. found in the animal and vegetable-based waxes.

Paraffin wax (or simply "paraffin") is mostly found as a white, odorless, tasteless, waxy solid, with a typical melting point between about 47-64 °C  and having a density of around 0.9 g/cm³. It is insoluble in water, but soluble in ether, benzene, and certain esters. Paraffin is unaffected by most common chemical reagents, but burns readily. Paraffin wax is generally unbranched hydrocarbon having carbon above C₁₇ and  are solid at room temperature. Their carbon atoms typically ranges between C₁₇ - C₃₀ and having typical melting point around 60°C. All paraffinic wax are recovered from fractional distillation of petroleum.The name paraffin implies that it contains straight hydrocarbon structure but it has branch also. Branched paraffins are called ‘Isoparafins’ and cyclic parafins are called ‘Cresines’ or ‘Isoceresies’.

Pure paraffin wax dose in rubber compounding varies from 1-3 phr. Pure paraffin wax is rarely used these days in rubber industry as it has oozing character and in excess it causes blooming on green rubber components, that results in reduction in compound tack. They are frequently blended with microcrystalline wax in rubber compounding therefore.

Pure paraffin wax is an excellent electrical insulator, with an electrical resistivity of between 10¹³ and 10¹⁷ ohm meter. This is better than nearly all other materials except some plastics (notably teflon or polytetrafluoroethylene). It is an effective neutron moderator and was used in James Chadwick's 1932 experiments to identify the neutron. Paraffin wax (C₂₅H₅₂) is an excellent material to store heat, having a specific heat capacity of 2.14–2.9 J g^–1 K^–1 (joule per gram per kelvin) and a heat of fusion of 200–220 J g^–1(joule per gram). This property is exploited in modified drywall for home building material.

Microcrystalline waxes: This is produced by de-oiling petrolatum, as part of the petroleum refining process. Microcrystalline wax contains a higher percentage of isoparaffinic (branched) hydrocarbons and naphthenic hydrocarbons. It is characterized by the fineness of its crystals in contrast to the larger crystal of paraffin wax. It consists of high molecular weight saturated aliphatic hydrocarbons with comparatively higher melting point than paraffinic wax. It is generally darker, more viscous, denser, tackier and more elastic than paraffin waxes. The elastic and adhesive characteristics of microcrystalline waxes are related to the non-straight chain components which they contain. Typical microcrystalline wax crystal structure is small and thin, making them more flexible than paraffin wax. It is commonly used in rubber formulation and cosmetic formulations.

Its usual carbon atom ranges from C₄₀–C₇₀ , having comparatively higher melting point (Fig.4) between 80-105 ⁰C because they have higher number of carbon. Common dose in rubber compounding is between 1-3 phr. Some time higher dose of  100% Micro crystalline wax is difficult to process and as a result they are often blended with paraffinic wax for rubber use. Blending is also done for economical reasons as microcrystalline wax is comparatively costlier. Paraffinic wax, having smaller molecular weight bleeds faster in cured rubber article, whereas, 100% micro crystalline wax  will have inherent resistance to faster volatilization and eventually, blended wax will have an intermediate property. Refineries may also utilize blending facilities to combine paraffin and microcrystalline waxes. This type of activity is prevalent especially for industries such as tire and rubber industries.

Higher dose of antioxidant and anti ozonates are always advised to add along with microcrystalline wax because the later help slower migration of antioxidant and antiozonates on the product surface and thereby increase on the product durability against ageing process. Tire curing bladder is often blended with 1-3 phr of microcrystalline wax.

Chlorinated Paraffin Wax

Upon chlorination of paraffinic wax we get Chlorinated Paraffin Wax(CPW). This is available in batch process that is processed from effective exothermic reaction. This reaction generates a by-product hydrochloric acid that is later removed out of the solution. Finally stabilizer and solution is mixed that provide the required final product, which is used in various industrial applications. With 30 to 70% chlorine and insolubility in water, these CPWs have low vapor pressure. Chlorinated Paraffin Wax is highly inert, insoluble in water and they have low vapor pressure. Generally used as plasticizers in plastic and elastomers, where flame retardant property is important.

Polyethylene waxes (PE-Wax)

Polyethylene waxes or PE-Wax is same familiar polyethylene chemical structure (Fig.5) but with lower molecular weight , generally around or less than 3000.This is a processing aid in elastomer and plastics but basically they are a form of synthetic resins. It is a white solid product (Fig.6) appears in the market as powdery, lumpy, or flaky product. It is a non-toxic product having concentrated distribution of molecular weight of 1500 with specific gravity about 0.94 with high softening point but low fusion viscosity with melting point; 112 - 118°C, melt peak 110 °C, flash point 210°C, minimum. It has excellent stability against polishing, scratch resistance, metal mark resistance, scuff resistance. PE-Wax is resistant to water and chemical materials.

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Kraton Corporation, a leading global producer of speciality polymers and high-value biobased products derived from pine chemicals, has revealed a new strategic initiative for its Berre, France facility. The plan involves streamlining its polymer operations to concentrate exclusively on manufacturing USBC products, which will result in the cessation of HSBC production at that site.

This move is designed to bolster Kraton's long-term competitiveness by optimising its manufacturing footprint in reaction to a global overcapacity for HSBC. The company has formally started an information and consultation process with the local Works Councils, with a final decision expected following this mandatory period. The company has reaffirmed its commitment to supplying HSBC from its broader global network and to leveraging its worldwide presence to continue adapting to market demands.

Prakash Kolluri, President, Kraton Polymers, said, “Our aim with this plan is to strengthen Kraton’s long-term competitive position by optimising our manufacturing footprint in response to changing market dynamics associated with global overcapacity of HSBC production capability. With this step, we are preparing Kraton for a sustainable future by securing Kraton’s position as the leading global HSBC producer. Kraton is fully committed to supporting our customers through this transition with supply of HSBC products produced within our unmatched global manufacturing network. We recognise the impact of these actions, and are committed to a safe, respectful and supportive transition. The health, safety and well-being of the employees remain our top priorities.”

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Continental is accelerating its transition towards a circular economy by systematically increasing the use of renewable and recycled materials in its tyres. The company, which averaged a 26 percent sustainable material share in 2024, has set an ambitious target to raise this to at least 40 percent within five years. This strategy involves not only internal innovation but also actively encouraging its supply chain to develop and provide more sustainable raw materials.

A critical area of development is finding green alternatives for reinforcement materials like steel and textiles, which are essential for tyre safety, durability and performance. These materials can constitute over 18 percent of a passenger car tyre, and even more in commercial vehicle tyres. Continental is already integrating recycled steel and is pioneering the use of polyester yarn made from recycled PET bottles. Depending on the tyre size, the carcass of a single passenger car tyre can incorporate the equivalent of up to 15 bottles. This recycled polyester, developed with partner OTIZ, is verified to cut CO₂ emissions by approximately 28 percent compared to conventional materials and is already featured in production tyres like the UltraContact NXT.

The company's sustainable material portfolio extends beyond reinforcements. It includes synthetic rubber derived from used cooking oil, bio-based resins from waste streams and silica obtained from rice husk ash. Complementing these material advances is a commitment to greener manufacturing processes. Together with Kordsa, Continental has developed COKOON, an adhesion technology that bonds textiles to rubber without harmful chemicals. In a move to uplift the entire industry, this innovative solution has been made available to all tyre manufacturers as a free, open-source license, demonstrating Continental's broader commitment to fostering industry-wide sustainability.

Dr Matthias Haufe, Head of Material Development and Industrialization, Continental Tires, said, “We are not reinventing the wheel – but we are reinventing the tyre, with more sustainable materials and more environmentally compatible production processes. It’s not just about the rubber itself. We also focus on the materials that give the rubber its shape and make tyres stable and safe. Recycled steel and polyester yarn made from recycled PET bottles are important for more sustainable tyre production. Our goal is to use at least 40 percent renewable and recycled materials in our tyres within five years. Every alternative material brings us an important step closer to this goal. When it comes to sustainability, it’s not just the materials we switch to, but also those we deliberately do without.”

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Pyrum Innovations AG has officially announced that it will break ground on its next wholly-owned recycling facility in Perl-Besch on 14 November 2025. This new facility is a landmark project for the company, designed to be its largest to date and more than double its existing recycling capacity by processing in excess of 22,000 tonnes of used tyres each year.

The financial framework for this expansion is already taking shape. The project is supported by a diversified funding strategy that includes drawing on a EUR 25 million credit line from BASF and a committed debt financing term sheet from a major European bank. Finalising the package is contingent upon an agreement with Saarland authorities regarding land costs. Crucially, securing the Perl-Besch financing will unlock access to further substantial funding, including a second loan tranche from BASF, paving the way for additional projects in the company's rollout plan.

From a technical and logistical perspective, the Perl-Besch plant will be a state-of-the-art operation. It will be constructed on a 25,000-square-metre site in the strategically important border triangle of Germany, France and Luxembourg. The integrated facility will comprise a shredder plant, three next-generation Pyrum reactors, its own power plant and a grinding and pelletising plant. Insights gained from the existing plant in Dillingen are being directly applied to optimise construction and commissioning, aiming for a faster ramp-up to full production. The site was selected for its superior logistical advantages, offering direct connections to the Moselle River, railway lines and a nearby motorway to efficiently manage material flows from across Europe.

This new facility is central to Pyrum's financial roadmap, with the company projecting it will reach break-even upon its commissioning in 2027. Achieving this milestone is anticipated to create significant momentum and provide a solid foundation for the accelerated rollout of the company's broader project pipeline.

Pascal Klein, CEO, Pyrum Innovations AG, said, “Now that all the legal formalities have finally been clarified – development plan, planning permission and access to the site – we can hardly wait for things to visibly get underway. In the background, planning is already well advanced: The site has been prepared, numerous plant components with long delivery times – so-called long leads – have been ordered and the architect’s tenders for the ground work are underway. During construction, we will also benefit from the experience we have gained from the expansion of our main plant in Dillingen, so we are planning to start production in Perl-Besch in 2027.”

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Capital Carbon, a brand under India's Rathi Group, has successfully commissioned its new greenfield Recovered Carbon Black (rCB) facility in Gummidipoondi, Tamil Nadu. This development dramatically boosts the group's total rCB manufacturing capacity to 20,000 metric tonnes per year, a significant rise from its previous 5,000-tonne capacity.

The group distinguishes itself through complete vertical integration, handling the entire process from shredding end-of-life tyres to pyrolysis. This operation transforms waste into valuable materials, including rCB, fuel oil, steel wires and pyrolytic gas. The company utilises this gas for process heating, while the carbon char is either refined into rCB or supplied to cement plants as a sustainable energy source.

Ravi Rathi, Director, Rathi Group, said, "As Recovered Carbon Black gains wider acceptance, the industry continues to prioritise quality and consistency – and that's exactly what we've focused on addressing.”

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