Tall oil fatty acid (TOFA, CAS 61790-12-3) is a quiet workhorse of the lubricant industry. Its esters and soaps appear in metalworking fluids, grease, rolling oils and lubricant additives — where its unsaturated fatty acid chemistry and low cost make it a preferred bio-based feedstock. This article looks at how TOFA is used in lubricants and metalworking fluids, and what buyers should consider.
1. Why Fatty Acids in Lubricants?
Fatty acids and their derivatives contribute several functions in lubricants:
- Friction modification: fatty acid molecules adsorb onto metal surfaces, forming a low-friction film.
- Extreme-pressure (EP) behavior: fatty acids react at high contact temperatures to form soap films that protect surfaces.
- Emulsification: fatty acid soaps and esters help stabilize oil-in-water emulsions used in metalworking.
- Corrosion protection: fatty acid derivatives act as rust inhibitors in metalworking fluids.
TOFA is attractive because it delivers these functions at a lower cost than refined oleic acid, and its C18 unsaturated profile is well suited to the chemistry.
2. Key TOFA Derivatives in Lubricants
| Derivative | Function | Typical application |
|---|---|---|
| TOFA esters (e.g. TMP, pentaerythritol esters) | Base oil / lubricity additive | Metalworking fluids, rolling oils, grease |
| TOFA soaps (e.g. calcium, lithium) | Thickener for grease | Lithium and calcium greases |
| Amine salts of TOFA | Emulsifier, corrosion inhibitor | Soluble cutting oils |
| Dimer acids (from TOFA) | Corrosion inhibitors, additive intermediates | Rust preventives, additive packages |
3. Metalworking Fluids
In water-soluble cutting and grinding fluids, TOFA soaps and esters help form stable emulsions, provide boundary lubrication at the tool-workpiece interface and protect the workpiece from corrosion. The fatty acid content reduces friction and heat, extending tool life and improving surface finish. Formulators choose TOFA-based emulsifiers for a good balance of emulsion stability, lubricity and cost.
4. Greases
Calcium and lithium soaps of tall oil fatty acids are used as grease thickeners. TOFA’s fatty acid profile gives the soap the right consistency and shear behavior, and its low cost keeps grease prices competitive. Specialty greases may use higher-rosin TOFA grades where color is not critical.
5. Choosing TOFA for Lubricant Applications
- Acid value: higher acid value (e.g. 192) gives more reactive fatty acid for esterification and saponification.
- Rosin content: lower rosin improves color and consistency of esters; high-rosin grades may be acceptable in dark greases.
- Iodine value: affects oxidation stability; higher unsaturation means better lubricity but lower oxidative stability.
- COA verification: confirm acid value, rosin, moisture and color per batch.
6. FAQ
Is TOFA a good base oil?
TOFA itself is not a base oil, but its esters (e.g. trimethylolpropane and pentaerythritol esters) are excellent bio-based lubricant base stocks and lubricity additives.
Can TOFA replace oleic acid in metalworking fluids?
In many formulations yes, at lower cost. The exact performance depends on the rest of the package — test the full formulation before switching.
Does TOFA improve EP performance?
Fatty acids provide mild EP/boundary lubrication by forming soap films; for heavy-duty EP performance they are combined with sulfur, phosphorus or chlorine additives.
Is TOFA-derived lubricant biodegradable?
TOFA and its esters are bio-based and generally more biodegradable than mineral-oil-based products, which is a growing advantage in environmentally sensitive applications.
PolyblueChem supplies tall oil fatty acid (TOFA, CAS 61790-12-3) suitable for lubricant and metalworking applications, with COA and MSDS. See our TOFA grades guide for specification details. Contact us for quotations.