DIFFERENT WAXES IN RUBBER INDUSTRY

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  • June 26, 2020
DIFFERENT WAXES IN RUBBER INDUSTRY
  • 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
Fig No 1

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
    Fig No 2
    Petroleum Based Wax

     

  • 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’.

Fig.3: Paraffinic  Wax
Fig.4: Micro Crystalline Wax

 

 

 

 

 

 

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.

Fig.5: Polyethylene, Fig.6: Polyethylene wax
Fig.7: Chlorinated Polyethylene waxes (CPE)

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.

 

Rubber Board Extends Planting Aid Schemes At Current Rates For 2026-27

Rubber Board Extends Planting Aid Schemes At Current Rates For 2026-27

The Rubber Board of India has confirmed the continuation of all existing central sector schemes for the 2026-27 fiscal year at unchanged rates. Financial aid for new planting will be restricted to estates utilising poly bag or root trainer plants sourced solely from Board-approved nurseries, with applicants required to submit the original purchase bill. This mandatory verification step aims to ensure quality and authenticity of planting materials used across the sector.

Support for rain guarding and spraying operations will be channelled exclusively through Rubber Producers’ Societies. These societies must include GST bills for all acquired materials when applying. The official timeline for submitting applications will be announced separately by the Board, giving producers adequate time to prepare documentation and coordinate with their respective societies before the deadline.

Rubber Board Calls For Marketing Graduates With Digital Skills For Temporary Engagement

Rubber Board Calls For Marketing Graduates With Digital Skills For Temporary Engagement

The Rubber Board of India has announced a temporary engagement for a young professional within its Market Promotion Division, located at the RRII campus in Puthuppally, Kottayam. The selected individual will assist with division activities and promote ‘mRube’, the electronic trading platform for natural rubber.

Candidates must hold an MBA in Marketing or Agri Business Management with computer knowledge, while skills in digital marketing, sales or market research and proficiency in English and Hindi are preferred. Applicants aged up to 30 years as of 1 May 2026, will be considered for the one-year role, which offers a consolidated monthly pay of INR 25,000.

Interested individuals should send their applications to the Deputy Director (Marketing) at the Central Laboratory Building, RRII, Rubber Board PO, Kottayam – 686009 by 19 May 2026. Shortlisted names will appear on the Rubber Board’s website with interview details, as no separate communication will be sent.

Bekaert Finalises Acquisition Of Bridgestone’s Tyre Reinforcement Plants In China And Thailand

Bekaert Finalises Acquisition Of Bridgestone’s Tyre Reinforcement Plants In China And Thailand

Bekaert has officially finalised its acquisition of Bridgestone’s tyre reinforcement operations in China and Thailand, after securing all necessary regulatory approvals and meeting standard closing conditions. The deal, now fully completed, marks a significant step in the Belgian company’s expansion strategy.

The transaction brings under Bekaert’s control two production facilities: Bridgestone (Shenyang) Steel Cord Co., Ltd. in China and Bridgestone Metalfa (Thailand) Co., Ltd. in Thailand. These plants specialise in manufacturing high-quality tyre cord products exclusively for Bridgestone tyres, and they will continue to supply Bridgestone under the new ownership, further deepening the longstanding partnership between the two firms.

Financially, the acquisition is expected to add roughly EUR 80 million to Bekaert’s annual consolidated sales. The EUR 60 million cash consideration for the deal was funded from the company’s available cash reserves.

Curd Vandekerckhove, CEO Rubber Reinforcement, said, “With the completion of this acquisition within our Rubber Reinforcement division, we are pleased to officially welcome the plant teams in China and Thailand to Bekaert. Our immediate focus is on a smooth transition and operational continuity while continuing to serve Bridgestone as a key strategic partner. The completion of the acquisition further strengthens the position of Bekaert in the tyre cord market, expands the global manufacturing footprint and deepens our longstanding partnership with Bridgestone. A long-term supply agreement ensures continued delivery of high-quality tyre reinforcement within a trusted supplier model.”

ANRPC Publishes Monthly NR Statistical Report For March 2026

ANRPC Publishes Monthly NR Statistical Report For March 2026

The Association of Natural Rubber Producing Countries (ANRPC) has released its Monthly NR Statistical Report for March 2026, revealing a market that turned external pressures into clear price gains. While February had hinted at shifting dynamics, March provided proof of the industry’s core strength, with prices rising across all major grades and trading hubs despite an unusually challenging global environment. A 3.4 percent drop in monthly output and a dramatic 42.51 percent spike in Brent crude prices allowed natural rubber to advance rather than retreat.

Benchmark grades recorded widespread increases. In Kuala Lumpur, SMR-20 reached an average of USD 2.04 per kilogramme, while Bangkok saw STR-20 climb to USD 2.20 and RSS-3 jump to USD 2.56 per kilogramme. Kottayam’s RSS-4 averaged USD 2.35, and centrifuged latex in Kuala Lumpur rose sharply to USD 1.72 per kilogramme. Futures markets echoed the trend, with Shanghai’s May contract averaging CNY 16,662 per tonne and Singapore’s June contract closing at USD 1.95 per kilogramme.

The supply situation tightened considerably. Global March production is forecast at 786,000 tonnes, with Thailand’s output falling to 164,000 tonnes as southern growing regions endured temperatures of 42 to 43 degrees Celsius and rainfall up to 69 percent below normal levels. These punishing conditions sent a clear message that the market can absorb demand without chaotic price swings, a sign of a maturing commodity sector.

Demand told a similarly positive story. China’s natural rubber consumption surged from 446,000 tonnes in February to 610,000 tonnes in March, supported by a manufacturing PMI of 50.4, a 74.4 percent monthly rise in vehicle output, and a 130 percent annual leap in new energy vehicle exports. Chinese imports jumped 39.03 percent month-on-month to 629,800 tonnes, while Vietnam, Malaysia and Thailand boosted exports by 47.34 percent, 13.73 percent and 8.3 percent, respectively.

The oil market further strengthened natural rubber’s competitive edge. With Brent crude averaging over USD 101 per barrel and peaking at USD 126.69 on 31 March, synthetic rubber became significantly less cost-effective, giving tyre makers a strong incentive to favour natural rubber. Policy moves also bolstered confidence, including Malaysia’s replanting aid increase to RM 20,000 per hectare and a new Indonesian research partnership on high-yield rubber tree genetics.

Looking ahead to the second quarter, the market enters the seasonal low-yield period with firming demand. New energy vehicle growth across Asia, an elevated oil floor, replanting investments and tightening supply all point to constructive pricing. Risks like trade disputes, weather extremes and geopolitical tensions remain, but March data shows an industry turning uncertainty into opportunity.