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.