In the world of formulation science, achieving a stable interface between oil and water is a fundamental challenge. Sorbitan Esters (Span series) and Polysorbates (Tween series) serve as the essential chemical pillars for emulsification, solubilization, and stabilization across food processing, personal care, and high-performance industrial sectors. foodemul.com, as a leading supplier of high-purity surfactants, provides regulatory-compliant and batch-consistent solutions designed to optimize your product’s shelf life and performance.
Fundamental Chemistry: From Sorbitol to Synthetic Pathways
Understanding the molecular architecture of Spans and Tweens is the first step toward mastering their application. Both classes originate from sorbitol, a sugar alcohol, but diverge in their synthesis pathways to create a spectrum of lipophilic (oil-loving) to hydrophilic (water-loving) properties.
- Sorbitan Esters (Span Series): These are produced by the dehydration of sorbitol into sorbitan, followed by direct esterification with fatty acids such as lauric, stearic, or oleic acid. Because they retain the hydrophobic nature of the fatty acids, Spans are inherently lipophilic.
- Polysorbates (Tween Series): To create these hydrophilic surfactants, a Sorbitan Ester is treated with ethylene oxide (ethoxylation). This adds long polyoxyethylene chains that act as “anchors” in the water phase, making Tweens highly water-soluble and effective O/W emulsifiers.
The HLB System: Your Blueprint for Emulsion Stability
The Hydrophilic-Lipophilic Balance (HLB) system is the essential tool for selecting the correct emulsifier. It is a scale from 0 to 20 that quantifies a surfactant’s balance between its water-loving and oil-loving properties.
- Low HLB Values (1.8 – 8.6): Predominantly the Span series. These are ideal for water-in-oil (W/O) emulsions, acting as co-emulsifiers or crystal modifiers.
- High HLB Values (11.0 – 16.7): Predominantly the Tween series. These are excellent for oil-in-water (O/W) emulsions, solubilizing oils and fragrances into water, and acting as wetting agents.
Formulator’s Pro-Tip: Calculating Blend HLB
To achieve a specific required HLB (rHLB) for your oil phase, use the following formula to blend a Span and a Tween:
HLB_blend = (Wa × HLBa) + (Wb × HLBb)
Where Wa and Wb are the weight fractions of surfactant A and B in the blend.
Technical Specifications at a Glance
This table serves as a primary reference for formulators comparing the core foodemul.com product line:
| Product Name | Chemical Name | Primary Fatty Acid | Typical HLB Value | Primary Function |
| Span 20 | Sorbitan Monolaurate | Lauric Acid (C12) | 8.6 | W/O Emulsifier, Co-emulsifier |
| Span 60 | Sorbitan Monostearate | Stearic Acid (C18) | 4.7 | W/O Emulsifier, Crystal Modifier |
| Span 80 | Sorbitan Monooleate | Oleic Acid (C18:1) | 4.3 | W/O Emulsifier, Wetting Agent |
| Tween 20 | Polyoxyethylene (20) Sorbitan Monolaurate | Lauric Acid (C12) | 16.7 | O/W Solubilizer, Emulsifier |
| Tween 60 | Polyoxyethylene (20) Sorbitan Monostearate | Stearic Acid (C18) | 14.9 | O/W Emulsifier, Texture Modifier |
| Tween 80 | Polyoxyethylene (20) Sorbitan Monooleate | Oleic Acid (C18:1) | 15.0 | O/W Emulsifier, Dispersion Agent |
The Power of Synergy: Leveraging Span & Tween Blends
One of the most effective strategies in emulsion science is the use of co-emulsifiers. By blending a low-HLB Span with a high-HLB Tween, formulators can create a more robust interfacial film at the oil-water boundary. This synergistic approach prevents droplets from coalescing, significantly improving long-term stability and shelf life compared to using a single surfactant.
Application Matrix: Industry-Specific Solutions
- Food & Beverage: Span 60 acts as a dough conditioner and crumb softener in bakery items, while Polysorbate 80 is critical in ice cream to control fat globule destabilization and improve texture.
- Cosmetics & Personal Care: Tween 20 is the industry standard for solubilizing fragrances and essential oils in clear aqueous systems like toners. Blends of Span 60 and Tween 60 are workhorses for achieving elegant, stable O/W creams and lotions.
- Industrial Applications: These surfactants are used as lubricants and antistatic agents in textile processing, as well as emulsifiers in metalworking cutting oils.
Regulatory Compliance & Quality Assurance
Navigating global regulations is essential for market access. foodemul.com ensures our products meet the highest standards:
- Food Grade Safety: Compliant with E-numbers (E491-E495 and E432-E436) and FDA requirements.
- Chemical Compliance: Fully registered under REACH and compliant with industrial safety standards.
- Sustainability: We offer RSPO-certified options to support sustainable supply chain initiatives.
Ready to optimize your formulation? Contact the foodemul.com technical team today to request samples, detailed specifications, or a consultation for your next project.
