• 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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Hi-Green Carbon Limited has achieved a significant milestone in its sustainability operations by securing the prestigious ISCC EU Certification. This globally recognised endorsement highlights the company's adherence to rigorous international standards for environmental responsibility and supply chain integrity.

The certification verifies full compliance across the entire production process, from sourcing to delivery, emphasising traceability and operational transparency. It specifically validates the sustainable production of the company's key outputs, including recovered carbon black (rCB) and tyre pyrolysis oil (TPO). This accomplishment underscores Hi-Green Carbon’s commitment to circular economy principles and positions it as a leader in the production of sustainable industrial materials.

The company statement read: “This milestone not only strengthens our sustainability commitment but also deepens our collaboration with you, our valued clients and partners. With ISCC-certified products, you can have greater confidence in the environmental integrity and long-term sustainability of your supply chain, supporting your own green initiatives and carbon-reduction goals. We extend our sincere gratitude to our clients, partners, and team members for their consistent support and trust. Together, we are driving positive change and contributing to a cleaner, greener, and more circular future.”

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Bekaert has launched a sustainability label, inhera, to identify its top-performing solutions designed to help customers accelerate progress towards net-zero targets. The label is applied to products that meet defined criteria, including alignment with the EU Taxonomy Regulation, carbon-emission reduction, improved resource efficiency and support for circularity. Eight solutions currently carry the label.

The company said the initiative responds to rising expectations for transparency and credible sustainability claims. It presents inhera as a means of offering clearer information on the impact of its solutions across sectors including construction, automotive and energy.

The name reflects Bekaert’s stated commitment to integrating sustainability across its operations. Ann-Françoise Versele, Vice-President Sustainability, said: “Sustainability is inherent in everything we do at Bekaert. Through our products and processes, we aim to leave a legacy of sustainability for future generations. Our partners who choose inhera solutions are choosing to accelerate sustainability and create real impact.”

The eight labelled solutions include Ampact copper magnet wire for high-voltage electric-motor stators, which the company says delivers a 10 per cent reduction in direct CO₂ emissions. Flexisteel hoist ropes for elevators are designed to cut daily energy use by up to 36 per cent compared with traditional steel ropes.

Elyta Ultra and Mega Tensile tyre reinforcements provide up to 16 per cent CO₂ savings per tyre and support circular reuse. High-tensile steel cores for overhead power lines reduce steel consumption by more than 30 per cent.

Bezinal Vineyard Plus coatings, made with low-carbon raw materials, deliver more than 50 per cent CO₂ reduction and 14 percent lower life-cycle greenhouse gas emissions. Bezinox non-magnetic armouring wire for submarine power cables is engineered to extend cable life and reduce operating temperatures.

Next-generation hose-wire reinforcement uses 28 per cent less wire and 5 per cent less rubber per hose, resulting in up to 70 percent lower CO₂ emissions, while subsea cable armouring wire made from at least 70 per cent recycled steel offers more than 50 per cent CO₂ savings and is fully recyclable at end-of-life.

Bekaert said additional products will be added to the inhera label as further innovations are developed.

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Yokohama Rubber has reported new findings from an international research programme aimed at combating leaf fall disease, a fungal infection that has disrupted natural rubber production in Indonesia, the world’s second-largest supplier.

The results were presented on 9 December at the fifth Joint Coordinating Committee Meeting held at Universitas Indonesia. The initiative, formally titled “Development of Complex Technologies for Prevention and Control of Rubber Tree Leaf Fall Diseases”, forms part of the Science and Technology Research Partnership for Sustainable Development, a scheme run by the Japan Science and Technology Agency and the Japan International Cooperation Agency with support from Japan’s foreign and education ministries.

The project brings together Japanese industry, government and academic institutions, including the national research agency RIKEN, with Indonesian partners. Its objective is to maintain output from smallholders, who account for more than 90 per cent of Indonesia’s natural rubber production. The programme is pursuing several approaches: pesticide-based disease control; the development of disease-resistant clones; and early detection using satellite and drone imagery.

Yokohama Rubber, which uses natural rubber as a principal raw material for tyres, has been involved since the project’s launch in 2020. The company began assessing pesticide effects on rubber quality in 2024, following a screening process. Field tests on large plantations have shown that correctly applied pesticides do not impair the properties of raw or vulcanised rubber. Yokohama Rubber is now contributing to research on how such treatments may affect smallholders.

The group said its “Procurement Policy for Sustainable Natural Rubber” incorporates support for participants across the supply chain, including small-scale farmers. It expects its role in the project to aid the sustainable production of natural rubber and help stabilise smallholder incomes. Yokohama Rubber is also an official partner in a separate SATREPS initiative on using rubber seeds to develop environmentally focused products intended to mitigate global warming and plastic pollution.

Under its sustainability theme, “Caring for the Future”, the company has emphasised links between its commercial activities and broader environmental and social objectives.

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Australia has released its first national specification for the use of crumb rubber asphalt on local roads, a move intended to give councils clearer guidance on designing and maintaining light-to-medium-duty networks and to strengthen domestic recycling demand for end-of-life tyres.

The Crumb Rubber Modified Dense Graded Asphalt (CRM DGA) Model Specification for light to medium duty roads was published by the Australian Flexible Pavement Association (AsPA) following collaboration with Tyre Stewardship Australia. The document offers standardised technical requirements for councils, which manage about 75 percent of the national road network — roughly 675,000km of streets and community-level infrastructure.

Existing asphalt standards were largely developed for higher-order state roads, leaving local governments to interpret specifications that did not reflect lower traffic loads or the environmental conditions typical of suburban and regional networks. The new model specification aims to close that gap by setting guidance aligned with the factors that most influence degradation on council roads, such as surface ageing and weather exposure.

The specification promotes the use of crumb rubber modified binders, which can extend pavement life under light-to-medium-duty conditions. Incorporating recycled rubber also aligns with broader circular-economy policies across Australia’s states and municipalities, which are seeking to reduce landfill and illegal dumping while supporting domestic tyre-recycling capacity.

AfPA said the CRM DGA Model Specification V1.0, dated October 2025, is publicly available. It includes requirements for mix design and materials, construction processes such as compaction and temperature control, and performance testing suited to council networks. It also offers practical guidance on integrating reclaimed asphalt pavement content.

Local governments seeking case studies and procurement tools on crumb rubber applications can access Tyre Stewardship Australia’s Crumb Rubber Resource Centre for further technical and project information.

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