High-Purity Solvents, Personal Care

Sodium Lauryl Ether Sulfate (SLES)

Sodium Lauryl Ether Sulfate (SLES) is an anionic surfactant and detergent widely utilized in the cosmetic, personal care, and home care industries. It is synthesized through the ethoxylation of dodecyl alcohol (usually derived from palm kernel or coconut oil), followed by sulfonation and neutralization with sodium hydroxide. This ethoxylation process is a critical distinction from Sodium Lauryl Sulfate (SLS), as it significantly reduces the skin and eye irritation potential, making SLES a preferred choice for formulations intended for sensitive skin.

SLES is characterized by its superior foaming capabilities, excellent emulsification properties, and high efficiency in reducing surface tension. It remains effective across a wide range of water hardness and pH levels, providing a luxurious lather and effective degreasing. Commercially, it is most commonly distributed as a 70% active matter paste (SLES 70%), which offers logistical efficiencies, or a 25-30% aqueous solution for immediate formulation use. Its versatility, low cost, and high performance make it a fundamental building block in modern surfactant chemistry.

Attributes

Key Features and Benefits

Superior Foaming: Produces a rich, dense, and stable lather, which is a primary consumer requirement for cleansing products.
Enhanced Mildness: The ethoxylation step ensures the molecule is gentler on the skin and scalp compared to non-ethoxylated sulfates.
Hard Water Stability: Exhibits high resistance to divalent ions (calcium and magnesium), maintaining cleansing power in hard water conditions.
Viscosity Control: Responds exceptionally well to the addition of electrolytes (such as Sodium Chloride), allowing formulators to easily adjust product thickness.
Synergistic Compatibility: Works effectively in combination with other anionic, non-ionic, and amphoteric surfactants like Cocamidopropyl Betaine.
Biodegradability: Readily biodegradable under aerobic conditions, reducing its environmental footprint.

Specifications

Technical Highlights

Chemical Structure: CH₃(CH₂)₁₁(OCH₂CH₂)_nOSO₃Na, where ‘n’ typically represents 1 to 3 moles of ethylene oxide.
Active Matter Content: Standard grades include 70% (paste) and 28% (liquid) active surfactant concentrations.
pH Stability: Most stable in the pH range of 7.0 to 9.0; susceptible to hydrolysis in acidic environments below pH 4.0.
1,4-Dioxane Limits: Modern manufacturing utilizes vacuum stripping to ensure 1,4-dioxane byproducts remain within strict regulatory safety limits (typically <30 ppm or <10 ppm).
HLB Value: Possesses a high Hydrophilic-Lipophilic Balance, indicating strong water-solubility and oil-in-water emulsification capabilities.
Anionic Nature: Carries a negative charge, providing excellent removal of particulate soils and sebum.