Lithium Stearate is a lithium salt of stearic acid, appearing as a fine white to off-white powder. It is best known as the primary thickener in lithium-based greases, which dominate the global grease market due to their excellent temperature stability, water resistance, and mechanical durability.
Lithium stearate delivers reliable performance in industrial, automotive, and specialty applications where long service life, resistance to heat, and smooth lubrication are critical.
Composition & Chemical Structure
Lithium (Li⁺): Provides thermal stability and water resistance
Stearate Anion (C₁₇H₃₅COO⁻): Long hydrocarbon chain responsible for lubrication and thickening
Structural Features:
• Polar lithium carboxylate head
• Long hydrophobic C18 alkyl tail
• Amphiphilic soap-like structure enabling grease thickening and surface activity
Physical Properties
| Property | Typical Value |
|---|---|
| Appearance | White to off-white powder or granules |
| Odor | Mild fatty odor |
| Density | ~1.0 – 1.1 g/cm³ |
| Melting Point | ~220 – 225 °C (decomposes) |
| Solubility in Water | Insoluble |
| Solubility in Oils | Dispersible |
| Thermal Stability | Excellent (for a soap) |
| Electrical Conductivity | Insulating |
Functional Mechanical Behavior
Lithium stearate is not a structural material. Its performance is evaluated through tribological and rheological behavior, including:
• Grease consistency control
• Shear stability
• Oil retention and film formation
• Load-bearing enhancement
In lubricating greases, lithium stearate forms a fibrous soap network that traps oil, maintains structure under shear, and resists mechanical breakdown.
Strengthening & Tribological Role
• Forms boundary lubrication films on metal surfaces
• Reduces metal-to-metal friction and wear
• Prevents galling under high load
• Lithium ions cross-link fatty acid chains to form a thermally stable soap lattice
Key Characteristics
✔ High thermal resistance (120–150 °C continuous)
✔ Excellent water resistance
✔ Strong mechanical stability under shear
✔ Chemical compatibility with mineral and synthetic oils
Refining & Processing Properties
Manufacturing Process:
• Neutralization of stearic acid with lithium hydroxide
• Controlled heating for uniform soap formation
• Drying and milling into powder or granules
Grease Manufacturing:
• Dispersed into base oil
• Heated to form soap fibers
• Cooled under controlled shear to build grease structure
Available Forms
| Form | Typical Use |
|---|---|
| Fine Powder | Lubricant additives, plastics |
| Granules | Grease manufacturing |
| Pre-dispersed | Specialty lubricant formulations |
| Technical Grade | Industrial greases |
| High-Purity Grade | Cosmetics, pharmaceuticals |
Applications
Lubricating Greases (Primary Use):
• Automotive wheel bearings
• Industrial bearings
• Electric motor greases
• Chassis lubrication
Plastics & Rubber: Release agent, internal lubricant, mold-flow improvement
Paints & Coatings: Thickener, anti-settling agent
Pharmaceuticals & Cosmetics: Tablet lubricant, cream stabilizer
Advantages of Lithium Stearate
✔ Superior temperature stability over calcium and sodium soaps
✔ Excellent water resistance
✔ Long grease service life
✔ Cost-effective performance
✔ Proven global supply chain
Why Choose Lithium Stearate?
Lithium stearate is the global benchmark grease thickener, offering the best balance of performance, stability, versatility, and cost. Decades of industrial use and predictable behavior make it the preferred choice for automotive, industrial, and specialty lubrication systems.