• 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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Midas, Asia’s largest manufacturer of tyre retreading materials, has launched O-rings designed for off-the-road (OTR) tyres, aimed at delivering reliable sealing performance in demanding operating conditions.

The O-rings are manufactured using high-quality natural rubber and are formulated to improve physical properties and ensure dimensional stability. According to the company, the product has been tested over many years in harsh environments and is intended to provide consistent, trouble-free performance in OTR tyre applications.

Midas said only REACH-compliant raw materials are used in the manufacture of the O-rings, underscoring its adherence to safety, quality and international regulatory standards.

Founded 56 years ago, Midas supplies tyre retreading materials to customers in more than 60 countries. The company said the launch reflects its continued focus on developing performance-oriented solutions for the global tyre and retreading industry.

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Toyoda Gosei has successfully commercialised automotive weatherstrips using recycled rubber, starting with the new Toyota RAV4. This marks a significant breakthrough in a field where rubber has historically been difficult to reuse, often ending up incinerated instead of truly recycled. Unlike steel or plastic, rubber recycling requires devulcanisation, a complex process that traditionally weakens the material and leaves behind unpleasant odours.

Through dedicated refinement of its proprietary devulcanisation technology, the company has overcome these longstanding quality hurdles. The advancements have dramatically increased the usable proportion of recycled material in automotive parts from under five percent to 20 percent, an achievement honoured by a Toyota Motor Project Award.

Looking ahead, Toyoda Gosei aims to extend this technology beyond synthetic rubber to include natural rubber, which is used in far greater volumes. The broader corporate ambition is to collaborate with automakers and partners to establish a full circular system. This system would collect and regenerate rubber from end-of-life vehicles, positioning the company as an industry leader in enabling both decarbonisation and sustainable resource circulation.

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Pursuing its strategic goals for 2030, Michelin is actively extending its technological leadership into adjacent, high-value sectors. This expansion is being accelerated through two key acquisitions announced in recent months: Cooley Group and Tex Tech Industries. Both US-based companies are leaders in advanced materials, specialising in high-performance fabrics and coatings, and align strongly with Michelin’s own focus on innovation and quality while bringing complementary geographic and technical strengths.

Cooley Group, marking its centennial in 2026, excels in creating engineered polymer-coated fabrics. Its fully integrated production enables custom solutions for critical applications in healthcare, industrial containment and waterproofing. Similarly, Tex Tech Industries, with over a century of operation, designs and manufactures specialised textiles for extreme demands, including thermal protection systems for aerospace, fire-blocking aircraft interiors and advanced composite materials.

These strategic moves significantly bolster Michelin’s existing position in coated fabrics, notably through its European brand Orca. By integrating Cooley and Tex Tech, Michelin anticipates accelerating its global market reach and increasing the revenue of its Polymer Composite Solutions division by approximately 20 percent, equating to roughly USD 280 million. Given the growing scale of this business, Michelin intends to establish it as a dedicated reporting segment starting in 2026.

The acquisitions, slated for completion in the first half of 2026 pending regulatory approvals, will be transacted in cash, with financial terms currently undisclosed.

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Birla Carbon, a leading global manufacturer and supplier of high-quality carbon materials, has been awarded the prestigious Platinum sustainability rating by EcoVadis, ranking it within the top one percent of all assessed companies globally. This honour recognises the firm’s enterprise-wide leadership in integrating sustainability across its operations, innovation and value chain.

The evaluation specifically commended its strong performance across four key areas: Environment, Labor & Human Rights, Ethics and Sustainable Procurement. This achievement is further validated by extensive third-party certifications, with over 75 percent of operations certified to international standards including ISO 14001, ISO 50001, ISO 45001, SA8000 and ISO 27001, underscoring the consistency and strength of its sustainability management systems.

John Loudermilk, President and CEO, Birla Carbon, said, “This Platinum rating reflects the steady progress we are making in embedding sustainability at the core of our business. Our growth strategy is geared towards delivering sustainability through innovation, operational excellence and responsible practices across our global footprint. We continually invest in sustainability and circularity-driven processes, keeping our operations sustainably efficient while creating long-term value for our customers, partners, communities and employees. Our sustainability strategy, Share the Future, serves as a roadmap to a sustainable future and guides our actions towards our aspiration of reaching net zero carbon emissions over the next 25 years. Being recognised among the top one percent of companies globally is a testament to the commitment of our teams worldwide.”

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