baseöljyjä

Base oils, also known as base stocks, are the fundamental components of lubricants. They make up the largest percentage of a finished lubricant, typically ranging from 70% to over 99%. The performance of a lubricant is heavily dependent on the properties of its base oil. Base oils are broadly categorized into several groups, primarily based on their refining process and chemical composition.

Group I base oils are solvent-refined mineral oils. They are the oldest and generally least expensive type of base oil. Group I oils have a lower viscosity index, meaning their viscosity changes more significantly with temperature fluctuations, and they contain more impurities, such as sulfur and aromatics.

Group II base oils are produced through more severe refining processes, often involving hydrocracking. This results in higher viscosity indices, lower sulfur content, and greater oxidation stability compared to Group I oils. Group II base oils are predominantly used in automotive engine oils and industrial lubricants.

Group III base oils undergo even more extensive refining, typically through hydroisomerization or severe hydrocracking. These processes produce oils with very high viscosity indices, excellent low-temperature properties, and superior thermal and oxidative stability. Group III oils are often referred to as synthetic or synthetic-based oils due to their performance characteristics, although they are technically derived from petroleum.

Group IV base oils are exclusively polyalphaolefins (PAOs). PAOs are fully synthetic hydrocarbons manufactured through polymerization. They offer exceptional thermal and oxidative stability, a wide operating temperature range, and good low-temperature fluidity, making them ideal for high-performance applications.

Group V encompasses all other base oils not included in Groups I-IV. This category includes esters, silicones, polyalkylene glycols (PAGs), and vegetable oils. These base oils are often used for specific applications where their unique properties, such as extreme temperature resistance, biodegradability, or compatibility with certain seals, are required. The choice of base oil is critical in determining the lubricant's ability to reduce friction, wear, heat, and corrosion.