Lubricant Additive Packages for Lubricant Blenders
The economic case for lubricants
Lubricant blenders add lubricant additive packages to base oils to make industrial and automotive lubricants. In the UK alone, wear resulting from friction costs GBP £24 billion (US $37 billion) each year. This figure is equivalent to 1.6 % of the UK GDP. Improved lubrication reduces wear and mitigates costs.
What Makes a Base Oil Into a Lubricant?
A lubricant comprises a base oil plus a lubricant additive package. Lubricant additive packages comprise a careful balance of the following:
- base oil
- anti-wear and extreme pressure (EP) additives
- corrosion inhibitors
- metal passivators
Some additive types compete with each other for surfaces on which to act. Additionally, and usually separately, lubricant blenders add oil tackifiers, viscosity modifiers, friction modifiers, solid lubricant dispersions and pour point depressants for specific applications.
Extreme pressure & antiwear additives
The primary function of a lubricant is to reduce static and dynamic friction. Reducing the friction reduces the machine input energy requirements, preventing wear and extreme pressure damage to surfaces. Extreme pressure damage and wear damage occur under high pressure boundary conditions, where surfaces or small raised areas of surfaces (asperities) are in direct contact and rubbing against each other and this is mitigated by EP/antiwear boundary lubricant additives that react with the surfaces.
You can reduce the machine input energy requirements by reducing the wasted energy that the system loses as heat and/or sound. Moreover, there are two main ways in which a machine generates waste heat and sound energy. Internal friction in the fluid that results in shear heating of the fluid creates waste heat energy. Secondly, under boundary conditions, surfaces rubbing against each other generate waste heat and sound energy. . Formulators must tailor both the base oil and the additive mix towards mitigating this waste energy. Furthermore, they can achieve this by keeping the lubrication as close as possible to the ideal elasto-hydrodynamic condition. Generation of waste heat energy activates base oil oxidation.
All lubricant base oil types will oxidise and degrade over time . Consequently, antioxidants are an essential component of any lubricant additive package. The chemical reactions involved in oxidation of base oils are thermally activated. Furthermore, once the oil reaches thermal oxidation reaction activation temperatures, the rate of oxidation increases. Oxidation speeds up as temperature increases, due to increased collisions, in line with the Arrhenius equation.
At moderate temperatures the mechanism proceeds by a free radical route. However, at relatively high temperatures additional thermo-oxidative reactions may also occur. Lubricant blenders must, therefore, select an appropriate blend of antioxidants according to the operating temperature regime of the lubricant.
Corrosion inhibitors & metal deactivators
Base oils can contain a certain amount of water; some contain water inherently. Additionally, water vapour from the air can enter the oil, or it can condense in high atmospheric pressure components of a mechanical system. Wherever water comes into contact with metals, corrosion can occur and this causes damage to metal parts resulting in high replacement or repair costs. Corrosion inhibitors and metal passivators reduce the damage caused by corrosion to metal parts and the resulting repair or replacement costs.
Mineral oil or synthetic?
Mineral oil is a relatively low cost base for lubricants; however, it does have performance limitations. Specifically, at high temperatures, mineral oil oxidises and breaks down more readily than synthetic most synthetic base oils. For incidental food contact applications, most mineral oil is not food grade. Poly alpha olefins PAOs and polyisobutenes have much better high temperature and properties and better lubricity than mineral oil. Out of all of the conventional base oils, synthetic esters, have the best combination of properties for many high temperature applications. Brad-Chem distribute synthetic esters for Nyco. Due to Nyco’s background in aerospace and turbine lubrication, we are able to offer very highly advanced products.
Brad-Chem offers a very wide range of polybutenes (PIBs), with unrivalled security of supply. Furthermore, these products range from low molecular weight base oils, to high molecular weight solid rubbers. We offer products for use in caulks and sealants, food grade lubricants, plastics, rubber, cling film, and asphalt. We also offer a full range of PAOs for synthetic lubricants, compressor oils, engine oils, and gear oils.
Molybdenum Disulphide and Graphite
Molybdenum disulphide are lamellar solids. This means that they comprise macromolecular layers that can slide over each other, similar to a deck of cards. Moreover, this means that they act as solid lubricants in the same way that a deck of cards feels slippery. Brad-Chem is the UK distributor for Climax Molybdenum Molysulphide, sodium molybdate, molybdic oxide and ammonium molybdate products.
Additionally Brad-Chem manufacture and supply colloidal graphite dispersions and molybdenum disulphide dispersions. Lubricant blenders use these dispersions as a means of adding graphite or moly to oil or water. Additional applications include:
- forging and forming
- high temperature chain lubrication
- wire rope lubrication
- refractory applications
Speciality Lubricant Additive Packages for High Temperature Chains
Speciality lubricants require speciality lubricant additive packages. High temperature applications for lubricants have very diverse; therefore, there are few industry or OEM standards, and those that do exist are by no means universal.
The properties of a lubricant can change significantly at elevated temperatures. It follows that a lubricant that has been developed for one application or temperature regime may prove entirely unsuitable for another.
Brad-Chem has developed an extensive range of solutions for high temperature chain lubricant formulators. Contact us for further details.
Speciality Biodegradable Vegetable Oil Lubricant Additive Packages
Vegetable oils are natural esters with unsaturated fatty acid components. As such, they are inherently more susceptible to oxidation than other base oils. Therefore, any lubricant additive package for these product types must contain a careful blend of antioxidants.
Due to their derivation from natural plant sources, which are subject to climate conditions, the actual composition of these oils is variable. Moreover, exact compositions, even from the same supply source, may vary from crop to crop.
To date there are few established industry or OEM standards that apply specifically to lubricants made from vegetable base oils. Applications range from forestry / wood cutting and agricultural equipment to industrial compressor, hydraulic and gear oils.
Standards exist for mineral oil and synthetic oil based lubricants and the performance of a vegetable oil may be measured against these standards. However, the inherent variability of base oil supplies may mean that compliance of vegetable oil based industrial and agricultural lubricants can be subject to batch variation. For this reason, most approvals lie with the end users.
Speciality Food Grade Corrosion Inhibitors and Food Grade Lubricant Additive Packages
Lubricants, heat transfer fluids and cleaning products for the food production sector require incidental food contact approvals. These approvals are needed in case there is a risk of the lubricant coming into contact with food. In practice, this means that additives and additive packages or corrosion inhibitor packages must be selected from an inventory of registered and approved products for use in either incidental food contact applications or applications, with no possibility of contamination under normal circumstances.
Brad-Chem manufacture products registered an approved for HX-1, HX2 (lubricant additives approvals for incidental food contact and food processing equipment in which the lubricant has no food contact respectively), AX (incidental food contact cleaning product additive), GX (boiler water treatment) and HTX (heat transfer fluids). Find out more about our products for incidental food contact.