Causes and Solutions for Tar in Grease
During the use or storage of grease, tar-like substances are sometimes produced. This phenomenon is usually caused by thermal decomposition, oxidation, contamination or chemical instability of the grease. The following are the main reasons for the production of tar and the corresponding solutions:
- Reasons for Tar in Grease
High-temperature decomposition
When grease is exposed to high temperature conditions for a long time, it is easy to undergo thermal decomposition reactions to produce carbides and tar-like substances.
Common scenarios:
High-temperature lubrication environment (such as engine oil, gear oil).
Uneven heating or heating process with excessive temperature.
Oxidation
Grease reacts with oxygen in the air to produce oxidation products, such as organic acids, polymers or paint films, which eventually form tar-like deposits.
Key influencing factors:
The oxidation rate is accelerated at high temperatures.
Insufficient antioxidants in grease.
Influence of pollutants
External pollutants (such as moisture, dust, metal particles, etc.) mixed into grease will catalyze the oxidation and degradation of grease and produce tar.
Pollution source:
Metal wear particles.
Environmental impurities or aged sealing materials.
Additive instability
Some grease additives decompose at high temperatures or during long-term use, generating tar-like byproducts.
Problematic additives:
Poor quality antioxidants or anti-wear agents.
Components incompatible with base oils.
Grease aging
Grease stored for a long time will gradually degrade under the effects of temperature, oxygen and light, generating high molecular polymers and sediments.
- Measures to solve the problem of tar production in grease
Choose suitable grease
Choose grease with excellent high temperature resistance and antioxidant properties according to the conditions of use, such as:
Synthetic base oils (such as polyalphaolefins, ester greases).
Formulas containing high-efficiency antioxidants and anti-thermal decomposition additives.
Control the use temperature
Ensure that the operating temperature of the grease is lower than its temperature resistance limit and avoid long-term high temperature operation.
Use equipment with cooling devices or optimize the heat dissipation design.
Enhance antioxidant properties
Add high-efficiency antioxidants, such as:
Phenolic antioxidants (such as butylated hydroxytoluene, BHT).
Amine antioxidants (such as diarylamines).
Regularly test the oxidation stability of oils and greases (such as acid value, viscosity changes).
Prevent contamination
Strengthen the sealing design to prevent moisture and impurities from entering the system.
Regularly replace the filter element and clean the equipment.
Optimize the additive formula
Use additives with good high temperature stability to avoid incompatible chemicals.
Ensure the compatibility of additives with base oils.
Regular maintenance and monitoring
Regularly test the performance indicators of oils and greases (such as acid value, viscosity, particle content), and replace or add new oil in time.
Regularly clean the deposits or carbides that may accumulate in the equipment.
- The effect of tar on the performance of oils and greases
Increase equipment friction and wear, leading to lubrication failure.
Hinder heat conduction, which may cause local overheating.
Cause corrosion and shorten equipment life.
Affect the fluidity and lubrication effect of oils and greases.
The formation of tar in oils and greases is usually the result of a combination of factors, including high temperature, oxidation, contamination and improper formulation. To avoid the formation of tar, we should start from the selection of grease, control of use conditions, optimization of additive formula and equipment maintenance, and strengthen monitoring and regular maintenance. This can extend the service life of grease and equipment and improve operating efficiency.