Sorbitan Trioleate
Sorbitan Trioleate (STO) is a non-ionic sorbitan ester. It is a very low-HLB emulsifier, dispersant and oil-soluble surfactant, particularly suited to oil-rich systems and water-in-oil emulsions.
With an HLB of approximately 1.8, STO is more lipophilic than Sorbitan Monooleate (SMO), making it especially useful where strong oil compatibility, hydrophobic dispersion and low-HLB emulsification are required. It can also be combined with higher-HLB surfactants to adjust emulsifier balance in more complex formulations.
Product Information
Chemical family: Sorbitan fatty acid ester / oleate ester
Chemical name: Sorbitan Trioleate
Common name: STO
INCI name: Sorbitan Trioleate
Type: Non-ionic surfactant / very low-HLB emulsifier
Appearance: Clear yellow to amber liquid
HLB: 1.8
Solubility: Oil-soluble / highly oleophilic, with limited water solubility
Packaging: Drums / IBC / Bulk
Main functions
Water-in-oil emulsification
Supports the formation and stabilisation of W/O emulsions
Hydrophobic dispersion
Helps disperse oils, waxes, pigments, actives and other hydrophobic components
Oil compatibility
Highly compatible with oil-rich and oil-continuous systems
Co-emulsification
Can be used alongside higher-HLB surfactants to fine-tune emulsifier balance
Lubricity / process aid
Can support lubrication and processing performance in industrial systems
Formulation stabilisation
Helps improve consistency and reduce separation in oil-based formulations
Typical Uses by Industry
Personal Care & Cosmetics
Used as a non-ionic emulsifier in creams, lotions, make-up, sunscreens, cleansing oils and oil-rich cosmetic systems
Helps improve emulsion stability, spreadability and skin feel
Industrial & Technical
Used in oil-based emulsions, dispersions, wax systems, polishes and process chemicals
Suitable for formulations requiring very low-HLB emulsification and strong oil compatibility
Metalworking & Lubricants
Used as an emulsifier, co-emulsifier and lubricity aid in lubricant and metalworking fluid systems
Helps stabilise hydrophobic components and improve formulation performance
Textiles
Used as a lubricant, emulsifier and processing aid in textile treatment formulations
Helps improve fibre lubrication and dispersion of oil-based components
Agriculture
Used as an emulsifier and dispersant in selected agrochemical and crop protection formulations
Helps stabilise hydrophobic actives and oil-based formulation components
Household & Cleaning
Used in oil-based cleaners, wax emulsions, polishes and maintenance products
Supports dispersion and stabilisation of hydrophobic ingredients