• 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.

Orion Engineered Carbons, a specialty chemical company, started commercial sales in Italy from the first new reactor for carbon black production to be commissioned in the European Union in over 40 years. 

The new 25-kiloton line at the facility in Ravenna, in the northern region of Emilia-Romagna, produces both specialty and technical rubber carbon blacks, primarily for the European market, the company said in a release. 

Corning Painter, CEO, Orion, said, “The new line offers customers seeking long-term solutions a unique strategic opportunity to align with a dependable plant that has been operating for more than 60 years in Europe.” 

Additional investments at the plant include a new co-generation facility to convert waste heat into electricity, generating up to 120 MWh of electricity per year. Seventy percent of the electricity is supplied to the national grid, serving about 30,000 households. Orion is a net exporter of electricity in Europe and worldwide. (TT)  

Shin-Etsu Chemical, a leading chemical company, plans to invest $702 million in its silicone portfolio, a key component of its functional materials business segment.

This latest investment follows a plan announced in February 2022, worth $562 million, to meet the surging demand for advanced functional silicone products. However, due to the continuous growth in need, especially for eco-friendly options that align with the global goal of carbon neutrality, the company has decided to expand the applications of its silicone products. The company will also focus on enhancing the advanced functionality of its product lineup and further developing environmentally friendly silicones.

In alignment with its newly announced silicones investment plan, Shin-Etsu Chemical will make investments not only in its central production hub in Japan, the Gunma Complex in Gunma Prefecture, but also in its Naoetsu Plant in Niigata Prefecture, Takefu Plant in Fukui Prefecture, and the Group company plant in Thailand, where silicone monomer and polymer production is conducted. The company will also invest further in existing silicone plants across other Asian countries, the United States, and Hungary. Simultaneously, Shin-Etsu Chemical will accelerate efforts to achieve carbon neutrality by embracing greener manufacturing processes.

Klean Industries Inc has announced that its partner Pyrolysis Hellas SA has completed Phase II of the Detailed Feasibility Study to design and build a tyre pyrolysis plant in Greece. Greek Authorities gave permits to its final Phase, the company said in a release. The company, while terming it as a significant milestone for the PHS project, claimed that it was the first tyre pyrolysis and carbon upgrading project in Greece to receive full authorizations.

Klean Industries Inc has announced that its partner Pyrolysis Hellas SA has completed Phase II of the Detailed Feasibility Study to design and build a tyre pyrolysis plant in Greece. Greek Authorities gave permits to its final Phase, the company said in a release. The company, while terming it as a significant milestone for the PHS project, claimed that it was the first tyre pyrolysis and carbon upgrading project in Greece to receive full authorizations.

Klean Industries Inc has announced that its partner Pyrolysis Hellas SA has completed Phase II of the Detailed Feasibility Study to design and build a tyre pyrolysis plant in Greece. Greek Authorities gave permits to its final Phase, the company said in a release. The company, while terming it as a significant milestone for the PHS project, claimed that it was the first tyre pyrolysis and carbon upgrading project in Greece to receive full authorizations.Klean Industries Inc has announced that its partner Pyrolysis Hellas SA has completed Phase II of the Detailed Feasibility Study to design and build a tyre pyrolysis plant in Greece. Greek Authorities gave permits to its final Phase, the company said in a release. The company, while terming it as a significant milestone for the PHS project, claimed that it was the first tyre pyrolysis and carbon upgrading project in Greece to receive full authorizations.

Each year, over 1.5 billion tyres are sold worldwide, representing more than 26 million metric tonnes, and just as many tyres each year also fall into the category of end-of-life tyres providing a large and partially untapped potential for resource and material recovery. Today, most traditional ELT treatment processes are not circular and do not result in any production of raw materials that are suitable to be reused in the tyre manufacturing industry. Without such ELT solutions in the EU, more than half of the EU end-of-life tyres and secondhand tyres are landfilled or are exported as tyre derived fuels for use into furnaces as an industrial fuel. The PHS project intends to reverse these trends and create a vibrant addition to advancements being made in the tyre recycling sector, the release said.

The PHS project is co-owned by Karabas European Hellenic Recycling. Currently, KEHR collects and recycles all types of scrap vehicle tyres and recycles them through traditional methods by shredding tyres into rubber granules, rubber powder & shock-absorbent surfacing slabs.

PHS has partnered with Klean Industries to build a modern tyre recycling facility that encompasses a state-of-the-art scrap tyre pyrolysis plant to recycle 20,000 TPA of waste tyres into valuable chemical products.

PHS proposes to construct and operate the Waste Tyre Pyrolysis Plant in Moulkia, a seaside town near Skala, Greece. It is located at an existing industrial site that is owned by KEHR, the release added. (TT)

ResiCare, an adhesive manufacturing subsidiary of Michelin, has found commercial use in Allin's plywood manufacturing unit, R'PLY. Allin and Michelin have been in collaboration since 2018.

The company claims that R'Ply is the first responsible plywood made using certified Poplar wood and integrating a ResiCare resin that is kinder to human health as well as the environment. The R’Ply is a high-performance plywood which can be used for multiple applications, according to the company. The plywood can be used for boat-building or in the building trade and will be available at certain DIY stores soon.

Michelin had set up a mobile ResiCare production unit at its Olsztyn site in May 2021. The company hopes to replace more than 80 percent of the usual adhesive used in its tyre textile reinforcement with the new ResiCare adhesive, which is free from any substances of very high concern for health (SVHC), by 2025. The company further plans to set up mobile production units similar to the one in Europe and Asia in the coming months. (TT)