A Quick Guide to Hydraulic Fluids

Hydraulic oils are critical components of hydraulic systems, serving as the lubricant and coolant for hydraulic pumps, valves, cylinders, and other components. With a wide variety of hydraulic oils available on the market today, selecting the right hydraulic oil for a particular application is critical to ensure maximum performance, reliability, and longevity of hydraulic systems.

Types of Hydraulic Fluids

There are several types of hydraulic oils available on the market, including mineral oils, synthetic oils, and biodegradable oils. Mineral oils are the most common type of hydraulic oil, made from crude oil and refined through a distillation process. These oils are affordable, widely available, and have good lubrication properties. However, they have limited resistance to oxidation, which can lead to oil breakdown and sludge formation.

Synthetic oils are engineered oils that provide superior performance and durability compared to mineral oils. They are made from a variety of base stocks, including esters, polyglycols, and silicones, and are often blended with additives to improve lubricity, anti-wear properties, and resistance to oxidation. Synthetic oils are generally more expensive than mineral oils, but they offer better performance and longevity, making them ideal for high-pressure hydraulic systems and extreme temperature environments.

Biodegradable hydraulic oils are specially formulated to meet environmental regulations and minimize ecological impact. These oils are made from vegetable oils, esters, or other biodegradable base stocks, and are designed to break down quickly in the environment. Biodegradable oils are typically more expensive than mineral and synthetic oils, but they offer superior environmental performance and safety.

Water-glycol fluids are a mixture of water and glycol, and they are known for their excellent heat dissipation properties. They are commonly used in high-heat applications, such as in steel mills and other heavy-duty industrial applications. However, they are not as widely used as mineral, synthetic, or bio-based oils, and they are generally more expensive.

Factors for Selecting a Fluid

When selecting a hydraulic oil, it’s important to consider the specific requirements of the hydraulic system and the operating conditions. For example, hydraulic systems operating in cold environments may require a hydraulic oil with low pour point to ensure adequate fluidity and lubricity. Similarly, hydraulic systems operating in high-temperature environments may require a hydraulic oil with high thermal stability to prevent oxidation and viscosity breakdown.

Different hydraulic oils also have different viscosity grades, which determine the flow rate and resistance to flow of the oil. Viscosity grades are typically expressed in numbers, such as ISO 32 or ISO 46, with higher numbers indicating higher viscosity. The viscosity grade of the hydraulic oil should match the recommended grade specified in the equipment manufacturer’s manual.

In terms of cost and performance, mineral oils are the most affordable type of hydraulic oil, but they may require more frequent oil changes and maintenance due to their limited resistance to oxidation. Synthetic oils are more expensive, but they offer superior performance and longevity, making them ideal for high-pressure hydraulic systems and extreme temperature environments. Biodegradable oils are the most expensive, but they offer superior environmental performance and safety. The choice of oil will depend on the specific application and the user’s priorities.

Different hydraulic oil manufacturers may also have variations in their product formulations, additives, and performance characteristics. It’s important to choose a reputable manufacturer and ensure that the hydraulic oil meets the required specifications and performance standards for the specific application. Some of the most well-known manufacturers include Mobil, Shell, Chevron, and Castrol. These companies have a reputation for producing high-quality oils that are suitable for a wide range of applications. Other manufacturers may have a focus on a particular type of oil or a niche application.

Conclusion

In conclusion, selecting the right hydraulic oil for a particular application is critical to ensure maximum performance, reliability, and longevity of hydraulic systems. Mineral oils, synthetic oils, and biodegradable oils are the main types of hydraulic oils available on the market, each with their own advantages and disadvantages in terms of cost, performance, and environmental impact. When selecting a hydraulic oil, it’s important to consider the specific requirements of the hydraulic system and the operating conditions, as well as the viscosity grade and the reputation of the manufacturer. By choosing the right hydraulic oil, businesses can improve the efficiency and effectiveness of their hydraulic systems, minimize downtime and maintenance costs, and maximize the lifespan of their equipment.

Twin Specialties distributes a full line of hydraulic fluids and other industrial fluids to meet any and all manufacturing demands. Contact a Twin Specialties representative to learn more about our product lines and/or get a quote.

Understanding Multipurpose Greases

Since the invention of the wheel, operators have used grease to help run their bearings. Grease technology remained similar until the industrial revolution, where heavy machinery and advancing technology required lubricating grease to keep up. In the last few decades, grease technology has advanced so much that there is probably a grease tailor-made for any application. However, this has resulted in the loss of an “All-Purpose Grease.”

Multipurpose is not All-Purpose

Many applications are similar in regards to operating temperature, loads, speed, etc. and could be lubricated with the same grease. This creates an illusion that one grease can lubricate all of your machinery. It is tempting to do so because of the benefits of lubricant consolidation, increased purchasing power, and simplified lubricant storage. Greases are uniquely formulated to operate at certain loads, speeds, temperatures, etc. This means that a grease will work optimally for one application, but subpar for another.

In the transport industry, there used to be separate greases for chassis and wheel bearings. This changed when lithium greases emerged and proved to be suitable for both chassis and wheel bearings. These multipurpose greases became popular, but there were certifications needed in order to be truly “multi-purpose.” The National Lubricating Grease Institute (NLGI) has “L” certifications for chassis greases and “G” for wheel bearings. They were paired with an “A”, “B”, or “C” to denote the severity of operations; “A” being the lightest and “B”/”C” being the most severe duty. Most multipurpose greases carry the NLGI GC-LB certification. These are the gold-standard greases for heavy-duty transport operations.

The “Multipurpose” nomenclature is a great marketing tool, but can mislead people into thinking a grease has more “purposes” than it actually does. There is a place for multipurpose greases, but engineers have to evaluate the operation and the grease’s characteristics before selecting the appropriate greases and plans for consolidation.

Selecting the Proper Greases

Some OEM recommendations are simple like, “Use a lithium #2 grease.” Whereas others are complex and list different specifications that ensure optimal performance. Some specifications to consider include:

  • NLGI Grade/Thickness
  • Thickener Type
  • Base Oil Type and Viscosity
  • Dropping Point
  • Oxidation Stability
  • Pumpability
  • Water resistance characteristics
  • EP characteristics

These specifications will help guide you in selecting the appropriate grease. By evaluating these characteristics, you are less likely to over-consolidate your greases and achieve optimal performance. More greases mean a greater probability of cross-contamination, this can be mitigated with proper storage and labeling.

Twin Specialties offers a Full Line of Greases

When selecting the proper grease, talking to manufacturers and informed distributors helps greatly. Twin Specialties has a full line of greases from manufacturers like Shell and Castrol. We work with manufacturers to help find the right product that meets any OEM specification. Contact us if you are looking for the correct grease or just more information.

How Long is Lubricant’s Shelf Life?

When buying lubricants, you have to consider how long they will last. For high-volume users, this is not as much of an issue compared to smaller-volume users. High-volume users’ regularly consumer and reorder lubricants and typically have systems in place to monitor usage and spending. Small-volume users might be spread a drum or two of a lubricant through the course of a year. When consumption is spread out, you have to start to consider shelf-life into your purchasing decisions and operational processes.

Where can I find Shelf-Life Information?

Table made by George Wills and Dr. A.R. Landsdown

Information on a lubricant’s shelf life can be found on a technical or safety data sheet. If it is no t clearly defined, manufacturers and distributors can provide guidance on shelf life for its products. However, this information might be based on storage only or based on typical operations. George Wills and Dr. A.R. Landsdown provide a brief list of lubricants and their shelf-lives for products that have shorter shelf-lives.

Some technical data sheets (TDS) can show how long a lubricant can last in use before losing oxidation stability. This is measured in operating hours. Most oxidation tests will show a lubricant can last 5000+, 8000+, 10000+, etc. hours. However, like all scientific tests, this is done in a controlled environment (usually set by ISO or ASTM standards and specifications). We know that not every operating environment is like an ASTM or ISO test.

What Determines a Lubricant’s Shelf Life?

A lubricant’s shelf life depends on a variety of factors; some of which depend on the lubricant itself and some depend on usage. Greases have much shorter shelf life due to the presence of thickeners than oil-based lubricants. Highly-refined and synthetic oils have longer shelf lives due to better molecular stability. This is much more straight-forward and lubricant suppliers can inform you which lubricants last longer than others.

Using a lubricant is different for each operation. Some operations happen at low temperatures, others occur at high temperatures. The Arrhenius rate is a chemistry term that demonstrates how chemical reactions increase by changing temperature. For lubricants, as temperature increases by 10°C (18°F), the oxidation rate will double. The more oxidation that occurs, the faster a lubricant will break down and reduce the shelf life and effective use life.

Machinery Lubrication compiled a chart from its experts to show what can increase or decrease a lubricants shelf life.

Table Courtesy of Noria Corporation and Machinery Lubrication

 

How can you Reduce Oxidation?

Oxidation occurs when the lubricant comes into contact with air. Certain lubricants are more susceptible to faster oxidation and degradation due to the composition of the lubricant. However, these are known and can be accounted for, whereas human factors are a much greater influence on degradation and chemical stability.

Storage is key to maintain longer shelf-life and higher lubricant performance. Some things that can improve shelf-life include:

  • Storing lubricants in proper ambient temperatures. Cooler temperatures around 68°F are ideal.
  • Storing lubricants in dryer environments. Ambient humidity and moisture increase oxidation and lubricant breakdown.
  • Storing lubricants indoors. Outdoor storage can expose lubricants to more extreme and volatile conditions.
  • Storing lubricants in proper containers. Poor-quality steel containers can expose the oil to iron and fuel oxidation. Plastic or plastic-lined drums are ideal for storage.
  • Reduce agitation of the lubricant. The move the lubricant is agitated or moved, the more surface area of oil is exposed to air and can oxidize.
  • Evaluate usage and purchase lubricants accordingly. This smooths out spending, but also reduces the likelihood of using older products.
  • Practice First-In-First-Out (FIFO) when using lubricants. This prevents lubricants from sitting and aging.
  • Label lubricants, containers, and machines. Knowing when a lubricant was made or put into use allows individuals to be more mindful of when to change lubricants.

How do I Get Informed?

Unfortunately, there is no industry consensus on shelf-life. Following the tips above will extend and maintain shelf-life. Speaking with manufacturers, distributors, and engineers is the best option in getting product-specific shelf-life information. Manufacturers will know exactly what goes into their products and can provide shelf-life information and best practices for storage.

Twin Specialties can provide information about Best Practices for Lubricant Storage and Managing Metalworking Fluids. We work with manufacturers to provide transparency and information about lubricant shelf-life and usage. Contact Twin Specialties for information about lubricants, best practices, and shelf-life.

What are Fire Resistant Lubricants?

Fire-resistant lubricants are fluids that are used in applications and systems where the risk of ignition is high. Typically, these environments are near or contain: open flames, sparks, or hot metals. If an oil leak were to occur, the risk of injury, damage, and even death is magnified as sustained fires can occur. That is why fire-resistant lubricants have been developed and manufactured to protect personnel and equipment.

Why do I need a Fire-Resistant Lubricant?

Fire-resistant lubricants are most needed in environments need high-temperature surfaces and open flames. Regular fluids that have low flash points pose the greatest risks to fire and should be switched for fire-resistant lubricants that have higher flash points.

If using pressurized hydraulic lines, it is key to have a fluid with a high flash point as small leaks can aerosolize the lubricant easily. The lubricant spray is much more susceptible to fire. It takes much less heat to ignite and can spread to fluid reservoirs. The lubricant can ignite if it’s fire point and/or auto-ignition point is reached. The fire point is the temperature at which a fire is sustained and is typically several (50+) degrees higher than the flash point. Opting for fire-resistant fluids with higher flash points will reduce the risk of fire and damage.

Fire-Resistance Fluid Standards

The term “Fire Resistant” and “Fire Resistance” are often misinterpreted and sometimes overused. There is no single property or metric that conveys relative fire resistance. Metrics like flash point, fire point, and autoignition temperature are useful, but do not tell the whole story. Because of this, most fluids are vigorously tested and are classified as “fire resistant” if it can pass various tests and simulations.

The Factory Mutual Research Corporation (FM) developed key benchmarks for testing fire-resistance. FM tests every single commercially available “Fire Resistant” fluid to ensure it meets various benchmarks. FM 6930 is the standard for hydraulic fluids and is classified into 3 levels: 0, 1, and 2. This standard only measures a fluid’s flammability and does not consider other factors of the lubricant.

The Mine Safety & Health Administration (MSHA) has their own tests and standards for underground mines and applications. Their stringent testing produces more failures than FM. Both programs has strict auditing and inspection programs to ensure fire-resistant fluids meet performance standards.

Types of Fire-Resistant Lubricants

Oil-Water Emulsions

There are 2 types of oil-water emulsion fluids: oil-in-water and water-in-oil. Oil-in-water emulsions are formulated with oil droplets sustained in water. Approximately 95% of the fluid is made of water and the remaining 5% is composed of oil. These emulsions have excellent fire resistance and heat-transfer capabilities, but poor lubricity and poor corrosion protection.

Due to these poor lubricity characteristics, water-in-oil emulsions (also known as inverse emulsions) are better performing fluids. These are 40% water and 60% oil. It provides more balance of heat-transfer properties, lubricity, and corrosion protection. The fire-resistance primarily comes from the water, which turns into steam and reduces the oil’s combustibility.

Water Glycols

Water-in-oil emulsions have seen declining market share due to the rise of Water Glycol Fluids. Water Glycols contain 35-45% water and the remaining contents are some sort of glycol, such as ethylene glycol. These Water Glycols offer some benefits such as a lower freezing point and excellent fire resistance. Water Glycols do have drawbacks, but many of these can be mitigated by various additive packages. These fluids can be used in a variety of applications, but speed and strength ratings are reduced due to the limited performance of the fluid. Despite this, Water Glycols are one of the most popular fire resistance lubricants on the market today.

Phosphate Esters

Phosphate Esters provide the best fire resistance properties of any fluid. This is due to their natural molecular structure. They are non-corrosive, have excellent oxidative stability, great anti-wear characteristics, and are suitable for use up to 150 C. Despite this, they have been losing popularity due to stringent compatibility and maintenance concerns. They are still popular for aircraft and military applications. Additionally, they require special seals and coatings and require special care during disposal.

Polyol Esters

Polyol ester fluids have gained popularity due to its fire resistance properties, excellent lubricity, and good viscosity stability across different temperatures. These contain additive packages to impart good performance and high thermal properties. These are much more compatible and versatile than phosphate esters. This has led to their rising popularity and market share in recent years.

Maintenance and Other Considerations

When switching to fire-resistant fluids, compatibility must be considered before restarting the equipment. By carefully draining the machine, this decreases the likelihood of any incompatibility issues.

High-water content fluids require a lot more maintenance and care to ensure they perform properly. Water provides a great medium for bacteria and biocide treatments are recommended to prevent bacteria growth. As temperatures rise, water evaporates and needs to be replaced to ensure the fluids cooling properties are not compromised. pH levels should be monitored along with corrosiveness and wear protection. It is important to follow proper storage practices to maximize efficacy and shelf life.

Like any other oils, fire-resistant fluids degrade in heat and reduce oxidative stability. It is important to note rotating pressure vessel oxidation test (RPVOT) values to ensure your fluid has enough oxidative stability.

Conclusion

Fire-resistant fluids are great options for equipment and environments that are susceptible to fires. If you have high-pressure machines, it is imperative to consider fire-resistant fluids to prevent potential sprays that can ignite. Twin Specialties offers both water glycols and polyol esters to meet your needs. Contact Twin Specialties for product information.

How to Select the Right Grease

Selecting a grease or lubricant is one of the most crucial decisions you make in regards to any machine. Your selection might make the difference between cost savings, reduced downtime, or significant unexpected costs and failures. For oil lubricants, many OEMs specify what product or what type of product is recommended for each component of their equipment. This simplifies the selection process. However, OEM grease specifications are much broader. Most of the time OEMs simply recommend the National Lubrication Grease Institute (NLGI) specification.

This presents both flexibility and options, but also introduces more room erroneous decision-making and poor lubrication. Simply using the NLGI grade is not enough. You have to look at other factors to ensure you grease and machine work properly and does not fail. We will look at some key factors that every operator needs to consider.

Base Oil Viscosity

A grease is composed of 3 ingredients: thickener, oil, and additives. The NLGI number indicates the thickness of the thickener, but does not specify the viscosity of the thickened base oil. The underlying base oil has its own viscosity just like any lubrication oil. If a piece of a equipment calls for a certain lubricating oil with a specific viscosity, it is easy to find a grease that has the same base oil viscosity and similar additive package.

If viscosity requirements are not specified, you can use the chart below (courtesy of ExxonMobil and Noria).

The two factors required are operating temperature and DN or NDm, which are the bearing speed factors. To calculate those speed factors, simply use the following formula:

  • DN = (rpm)*(bearing bore) and
  • NDm = (rpm)*((bearing bore + outside diameter) / 2)

The intersection of DN and Temperature will point you towards the required ISO viscosity. This chart assumes viscosity index.

Base Oil Type and Additives

Once a viscosity is identified, you need to figure out what additives and base oil you need. Similar to oil lubricants you must assess your operations and figure what additives are necessary or unnecessary. For example, light loads and high-speed applications do not require a grease with extreme pressure (EP) additives, but a heavily loaded application will need those EP additives. The chart below breaks down the needed additives for various bearings.

Courtesy of Noria

Most greases use mineral oil and only require mineral oil. However, synthetic base oils are recommended for certain extreme temperature applications. Applications with low or high operating temperatures or a wide range of temperatures, a synthetic base oil is recommended. Synthetic base oil greases are also recommended for users who want to longer regreasing intervals.

Grease Thickener

Unlike lubricating oils, greases include thickeners. The two factors that distinguish grease are type and consistency. As mentioned earlier, consistency is based on the NLGI scale. The scale ranges from 000 (most fluid) to 6 (least fluid). The most common and most recommended NLGI grade is #2. Most OEMs specify the NLGI grade and matching that number is a simple process (especially if you require a NLGI 2 grease).

The other factor for thickeners is the type of thickener. The differences between each type of thickener are present pros and cons for each application. The most common types are lithium soap, lithium complex, and polyurea. Lithium soap greases are low-cost general-purpose grease and perform well in general applications. Lithium complex is similar to lithium soap, but is preferred for applications with higher operating temperatures. Polyurea greases have good high-temperature properties and have high oxidation stability and bleed resistance. When switching greases, it is important to understand thickener compatibility to make sure the new grease does not fail.

Cost and Other Considerations

When purchasing a grease, a basic lithium grease will be cheaper than a sophisticated polyurea grease. It is up to you to determine the tradeoffs between grease costs and performance gains/losses. Purchasing a higher quality grease may lead to longer regreasing intervals and less machine failure.

To save costs, consolidating greases may be wise, but be wary of over-consolidation. This may result in some machines not using an appropriate grease.

Other attributes should be considered depending on the application. Some grease exclusive attributes include:

  • Drop Point
  • Mechanical Stability
  • Water Washout
  • Bleed Characteristics
  • Pumpability

Certain attributes are focused specifically on heavy loads and should be considered for heavy load-low speed applications. These include:

  • Four-Ball Tests
  • Timken OK Load

Additionally, industry specific requirements will also dictate grease selection. These industries have strict requirements and require greases to be certified by certain 3rd-party regulators:

Conclusion

Unlike oils, greases have many more factors for product selection. These factors should be considered for each application as each grease is designed and manufacturer specifically for each application and have a delicate balance of thickener, oil, and additives.

Twin Specialties carries a wide variety of greases to meet you application needs. We work directly with you to make sure we provide the right product that delivers performance while being mindful of the total cost of grease and maintenance. Contact Twin Specialties to learn more about our grease product lines.

Lubricants for Cold Weather

During the winter months and in cold weather regions, operators will face cold starts regularly and must select lubricants that ensure proper performance and protect your machine or engine. We will focus on key features that will differentiate lubricants that excel in cold weather and lubricants that will lead to machine or engine failure.

Viscosity

Not all cold starts are equal. There are varying temperatures and the lubricant you need will depend on the ambient temperature. If temperatures are below -20 C/- 4 F, it is recommended to use base oils that can flow in low temperatures. For engine oils, using an SAE 0W or SAW 5W grade lubricant is recommended. When the temperature drops below -30 C/- 22 F, operators should use a SAE 0W or SAE 5W lubricant, but whose base oil is a synthetic base stock and/or a base oil that is considered “multi-grade” or “multi-viscosity.”

Many of these multi-viscosity and multi-grade lubricants are designed for extreme weather conditions including cold start conditions. These lubricants maintain their viscosity better than conventional lubricants. Generally, multi-viscosity lubricants exhibit viscosity characteristics found in 2 different ISO viscosity grades (i.e. ISO 32-46) and multi-grade lubricants exhibit viscosity characteristics found in 3 different ISO viscosity grades (i.e. ISO 32-46-68).

Viscosity Index

When the temperature drops, the lubricant becomes more viscous, thus making it more difficult to circulate and flow through the engine or machine. Having a lubricant with a high viscosity index, defined as a viscosity index greater than 130, ensures that your lubricant better maintains its viscosity in extreme temperatures. Lubricants with high viscosity indices have either a highly refined or synthetic base stock or include viscosity index improver additives.

Monograde lubricants will have viscosity indices in the 95-105 range and will not perform as well as in cold start conditions. Many operators will use different monograde lubricants depending on the ambient temperature. This may cause issues with change outs and cold temperature properties.

Pour Point

As mentioned earlier, not all cold starts are created equal. In colder temperatures, a lubricant’s pour point could be the difference between success and failure. Pour point is defined as when a lubricant no longer flows and congeals. When operating in temperatures below -30 C/-22 F, it is imperative to use a lubricant with a pour point lower than -50 C/-58 F. Similar to viscosity index, lubricants with highly refined or synthetic base stocks have lower pour points. Some lubricants are manufactured with pour point depressants that prevent wax formation and the congealing of the lubricant.

Oil Integrity and Storage

While you can meticulously select the perfect lubricant based on your OEM requirements, ambient climate, and budget, it could be costly if you do not maintain it properly. Just like any oil, it is important to regularly check the oil for cleanliness and contamination. Taking regular samples is key to ensure your lubricant and machine is in good health. When storing lubricants. It is helpful to store the lubricant indoors or in a warmer environment so that it flows easily during start-up. Proper storage will also protect against contamination. If contaminated, the additives such as VI improvers or pour point depressants may not be as effective and could hurt lubricant performance.

A Guide to Base Oil Groups

In any oil-based lubricant the base oil will compose 80-99% of the product you use. What are differences in the main ingredient of your lubricant? The American Petroleum Institute classifies base oils into 5 groups. These classifications are based on the chemical composition of the base oil and the treatment of the base oil.

If a base oil is classified as Group I-III, that base oil will be composed of crude oil that has been treated. The differences depend on the treatment processes applied to the oil.

Petroleum Base Oils

Group I

Group I base oils are the least refined base oil. Two main characteristics of Group I base oils are that they are composed of less than 90% saturates and/or greater than 0.03% sulfur. If either of these conditions are satisfied, then the base oil will be classified as Group I. The only process that is used is solvent refining, which allows Group I base oil products to be cheaper than their more refined equivalents. These are generally used for less-demanding applications and could be ideal for applications where lubricant consumption is high.

Group II

Group II base oils are more refined than Group I. In addition to solvent refining, these oils are also hydrocracked purify the oil. Unlike Group I base oils, these base oils must contain over 90% saturates and less than 0.03%. The greater percentage of saturates gives these lubricants better antioxidation properties than Group I base oils.

Failure to meet either of these requirements will result in a Group I classification. These products also have a viscosity index of 80-120. These oils have good performance in volatility, oxidation stability, wear prevention, and flash point. They only have fair performance in cold temperature environments. Given costs of treatment today, Group II lubricants are most commonly used today and many users have switched from Group I oils to Group II oils.

Unofficially, there is a Group II+ that are composed of high-end Group II base oils. These base oils must have a viscosity index of 110-120 to be considered Group II+.

Group III

Group II base oils must meet the same conditions (saturates and sulfur) as Group II, but also must have a viscosity index greater than 120. These base oils are severely hydrocracked, hydroisomerized, and hydrotreated to crate the best grade of petroleum base oil. These products offer superior stability and molecular uniformity, which makes them ideal for some semi-synthetic lubricants.

Some people consider Group III base oils to be synthetic. The API classifies them as mineral oil since they are derived from crude oil. They do mimic characteristics of synthetic oils including high viscosity indices. A lawsuit between Mobil and Castrol occurred due to Castrol marketing their Syntec lubricant as a synthetic even though it was composed of Group III base oils. In a 1999 ruling, the product was allowed to marketed as a synthetic.

Many people reject the decision and only consider Group IV and Group V base stocks as “synthetic.” Some Group III lubricants outperform Group IV lubricants if they contain excellent anti-wear, anti-oxidant, and other additives. Similar to Group II, Group III base oils have an unofficial Group III+, which consist of Group III oils that have a “Very High Viscosity Index (VHVI).” The VHVI minimum is anywhere between 130-140.

Synthetic Base Oils

Group IV

Group IV base oils are synthetic base oils that composed of polyalphaolefins (PAOs). These products have a viscosity index of 125-200. These base oils are not extracted from crude oil, but made from small uniform molecules. The uniformity and manufacturing of these oils allows for predictable properties that assure performance in tough conditions. These properties include extreme temperature stability, which makes these products ideal for cold and hot weather climates.

Lubricants composed of polyinternalolefins (PIOs) are considered to be in the unofficial Group VI. Similar to PAOs, PIOs use different chemicals in its synthesis process to obtain an even higher viscosity index. Their official API classification would be Group V. Certain food grade lubricants are composed of Group IV PAOs.

Group V

Group V base oils are any base oil that is not classified as a Group I-IV base oil. Common Group V base oils are polyalkylene glycols (PAGs) and various esters. One exception is white oil, which is a very pure lubricant commonly used in cosmetics and food processing. Also used in food grade lubricants, Group V base oils such as PAGs or esters can be used in certain biodegradable base stocks rather than vegetable or seed oils. It is important to note that most PAGs are only compatible with other PAGs.

Key Takeaways

When selecting a lubricant, it is important to understand what base oil is used. Given that the base oil is 80-99% of a lubricant, you should know what base oil you are using. Upgrading the Group III or Group IV could improve performance and reduce consumption. Twin Specialties offers a variety of industrial and specialty lubricants made from a variety of base stocks to meet your operating and budgetary requirements.

Pros & Cons of Biodegradable Lubricants

In the next installment of our Biodegradable Lubricants series we examine the pros and cons of biodegradable lubricants. How do these lubricants compare to their petroleum-based counterparts? Previously we examined: biodegradability standards, biodegradable base stocks and biodegradable lubricant products. However, are these products right for you? We will look at some pros and cons to see if biodegradable lubricants are the right choice for you.

Pros of Biodegradable Lubricants

  • Excellent lubricity; superior to that of mineral oil
  • Higher viscosity index than mineral and synthetic oils
  • Higher flash point than mineral and synthetic oils
  • Less toxic and readily biodegradable
  • Renewable and reduce dependency on imported petroleum
  • New biotechnology has produced genetically-modified seeds designed for use in lubricants
  • Metal-wetting attraction makes them good for keeping dirt and debris off metal surfaces
  • Water-soluble PAGs are ideal for fire-resistant lubricants
  • Ideal for industries and applications where oil comes in contact with the environment
  • No potential for bioaccumulation (build-up in organism fatty tissue)
  • Price premiums are expected to decline with further market development

Cons of Biodegradable Lubricants

  • Lubricity so potent, friction modifiers must be added to reduce slippage in certain applications
  • Insufficient oxidative stability; oil must be treated or modified to ensure performance (which increase costs)
  • Small amounts of water can cause serious foaming and degradation
  • Cannot withstand high reservoir temperatures (usually greater than 80 C)
  • Vegetable base stocks must be hydrogenated to combat low oxidative stability
  • Low pour point; can be improved by winterization
  • Synthetic esters can be used for cold-temperature environments, but reduce bio-based properties
  • Synthetic oils are limited to which additives they can use due to biodegradability standards
  • PAGs can emulsify water, which can cause foaming, sludge, and corrosion
  • High price premiums for synthetic-based products

Conclusion

Biodegradable lubricants have significant potential to perform better than mineral oils. Developments in biotechnology could allow for specially formulated base oils that will address the current short comings of vegetable oils. As demand increases, price premiums will decrease and the we will become less dependent on petroleum. Synthetic oils already provide superior performance, albeit at a higher cost. Environmental concerns will drive these developments and shift the lubricant market towards biodegradable and environmentally accepted lubricants. To learn more, check out this EPA report on Environmentally Accepted Lubricants (EALs).

Twin Specialties Offers Biodegradable Lubricants

No matter your application or environmental requirements, Twin Specialties can meet your manufacturing, marine, or agricultural needs. We offer a variety of lubricants including: Shell Naturelle, Castrol Performance Bio, and various Food Grade lubricants. Contact Twin Specialties for a quote.

What is Moly?

What is Moly?

Molybdenum Disulfide, simply known as Moly, is used both independently as a dry lubricant and as an additive in lubricating greases. Dry lubricants reduce friction between two sliding surfaces without the need for an oil medium. Dry lubricant molecules have a natural attraction to metal and adhere themselves to metal surfaces. These molecules create a layer of protection that prevents wear and tear as well as significantly improve lubricity of metallic surfaces.

How Does Moly Work?

When used on its own, Moly is impregnated into the surfaces of metal parts to improve the lubricity and protect the parts themselves. When used in greases and lubricants, the Moly attracts itself to the metal surfaces as an anti-wear surface coating. When used in lubricants, Moly’s efficacy is limited if the additive remains suspended. It is important to ensure that the Moly is compatible with the oil or grease. If it is not compatible, the compounds could drop out and plug oil passages and filters.

Moly has a variety of unique properties that distinguish itself from other solid lubricants and solid additives. These include:

  • An inherently low coefficient of friction
  • Strong affinity for metallic surfaces
  • Film forming structure
  • Stability in the presence of most solvents
  • Effective lubricating properties from cryogenic temperatures to 350 C in air
  • Efficacy in vacuum and aerospace applications

Moly Greases

Moly greases can have concentrations from anywhere from 1 to 20%. Typically, Moly greases typically contain 3 to 5% Moly. Moly greases are generally used in operations where high pressure metal surfaces are sliding against each other. These include roller bearings that have very heavy loads and shock loading. Moly greases are also recommended in slow or oscillating motion that is used in universal and CV joints. Moly greases used in high-speed bearings can create problems such as “skidding,” where a bearing roller fails to rotate a full 360 degrees.

Due to its lubricating abilities in vacuums, Moly and Moly greases are popular in aerospace applications. Temperature limitations for Moly are much higher in space (1200 C compared to 350 C in air) thus can withstand extreme temperatures in space. Moly is used for low speed systems such as solar array drives, sensors, and antenna scanners.

Conclusion

As a solid lubricant, Molybdenum disulfide (Moly) serves as a better lubricant and additive than graphite because of its ability to operate under very heavy loads and in vacuum environments. If your machine’s manual calls for a moly grease, it is important to ensure a moly grease is used and the moly grease is compatible with other lubricants in your equipment.

What are Biodegradable Lubricants?

As the world’s petroleum reserves are extracted, scarcity increases, thus driving oil and lubricant prices higher. This economic burden will force end-users and manufacturers to develop alternatives that are cost effective, readily available, and sustainable. The answer to these concerns are biodegradable lubricants.

Biodegradable Lubricants Defined

Biodegradable lubricants have the ability to degrade naturally by the actions of biological organisms. Petroleum is naturally occurring and is considered inherently biodegradable. However, that does not mean they can be marketed, sold, and treated as biodegradable. When we refer to biodegradable lubricants, we are discussing lubricants that are readily biodegradable.

Determining Biodegradability

Biodegradable lubricants must meet the ISO 9439 or OECD 301B standards. These standards state that a lubricant that has degraded by more than 60% within 28 days is readily biodegradable. The tests involve treating a lubricant sample with microorganisms in the presence of oxygen and measuring the CO2 produced by the microorganisms. As mentioned before, petroleum-based lubricants are inherently biodegradable, but not readily biodegradable because they fail to meet these standards. Petroleum-based lubricants naturally degrade at a rate of 15-35% in 28 days, falling short of the required 60%.

Additionally, the lubricant must be of “low toxicity.” There are a variety of tests used to determine toxicity. These tests involve fish, daphnia, and other organisms. In their pure form, mineral oil and vegetable oil show little toxicity, but lubricants are not just pure oil. As additives are incorporated into formulations, the toxicity increases. Additives are added to make up for any performance shortcomings of biodegradable base stocks.

Types of Biodegradable Base Stocks

Most biodegradable lubricants use vegetable oil, synthetic esters, polyalkylene glycols (PAGs), or a combination of these as base stocks. Vegetable oils have been used for years when petroleum was in short supply. They were popular during World War I and World War II due to oil rationing and came back in popularity during oil embargo in the 1970s. Vegetable oils declined in popularity due to the availability of low-cost oil after Desert Storm. Their popularity is beginning to rise as more manufacturers and end-users are faced with climate change and sustainability concerns. Some common vegetable oils used are soybean oil, cottonseed oil, olive oil, sunflower oil, and canola oil. To improve performance, farmers are beginning to grow genetically modified crops that are designed and engineered for use in lubricants.

Synthetic base stocks, such as esters and PAGs, are also used to boost performance when vegetable oils cannot get the job done. PAGs are effective, however they have a few issues that should be considered. PAGs are incompatible with other oils and can cause problems if inadvertently mixed with non-PAG oils. PAGs can also react poorly with seals and paints. This is why synthetic esters are preferred for biodegradable lubricants. Synthetic esters are typically added to vegetable-oil based lubricants to improve low temperature properties. These serve better than light mineral oils as synthetic esters are less toxic and more biodegradable.

Biodegradable Lubricant Products

Many applications and machines now can be lubricated with biodegradable lubricants and meet all performance requirements. Products that can be composed of soybean oils include:

  • Food grade hydraulic fluids and greases
  • Automotive, railroad, and machine greases
  • Tractor transmission and industrial hydraulic fluids
  • Chainsaw bar oils
  • Gear lubricants
  • Compressor oils
  • Transmission and transformer line cooling fluids

Many more products are in development and could become viable in lubricant markets soon. These include:

  • Two-cycle engine oils
  • Metalworking fluids
  • Specialty lubricants

With more resources and demand for biodegradable lubricants, engineers and manufacturers can research and develop more products that perform more applications, perform better than mineral oils, and remain price competitive.

Biodegradable lubricants are highly popular in applications and industries where environmental and safety concerns are high. Marine and agricultural industries need these lubricants as contamination could have devastating effects. According to Total Lubricants, a single liter of oil can pollute as much as 1,000,000 liters of water. In those applications, biodegradable lubricants are essential. Some government regulations ensure that these industries use biodegradable lubricants that do not harm consumers and operators in the event of leakage.

Twin Specialties Offers Biodegradable Lubricants

No matter your application or environmental requirements, Twin Specialties can meet your manufacturing, marine, or agricultural needs. We offer a variety of lubricants including: Shell Naturelle, Castrol Performance Bio, and various Food Grade lubricants. Contact Twin Specialties for a quote.