Soy Fatty Acid Diethanolamide (or DEA derived from soybean fatty acids) is a nonionic amide surfactant obtained by the reaction of soybean fatty acids with diethanolamine (DEA).
It is commonly used as a foam booster, viscosity enhancer, and secondary surfactant in detergent and cosmetic formulations.

General Formula

R–CO–N(CH₂CH₂OH)₂
where R represents the alkyl chain of the fatty acid (mainly C₁₆–C₁₈, saturated or unsaturated) derived from soybean oil.

Typical Properties of Soy Fatty Acid Diethanolamide

Property	Typical Value / Range
Appearance	Light yellow to amber viscous liquid
Odor	Mild, fatty, vegetable-like odor
Density (25°C)	0.95 – 1.02 g/cm³
Boiling Point	> 200°C (decomposes before boiling)
Viscosity (25°C)	Very high (1,500 – 3,000 cP)
pH (10% solution)	9.0 – 10.5
Solubility	Soluble in water and alcohols; partially soluble in non-polar solvents
Compatibility	Compatible with anionic, cationic, and nonionic surfactants

Applications of Soy Fatty Acid Diethanolamide (DEA)

Detergent and Cleaning Products

Enhances foam formation and viscosity in shampoos, dishwashing liquids, and body washes
Acts as a skin-conditioning agent in mild formulations
Serves as a co-solvent and foam stabilizer in nonionic cleaning systems

Cosmetics and Personal Care

Provides gentle foaming for baby shampoos and mild cleansers
Functions as an emulsifier and stabilizer in creams and lotions

Industrial Applications

Used in lubricant formulations and anti-static agents
Serves as an emulsion stabilizer in industrial degreasers

Advantages

Plant-derived and renewable source (soy-based)
Biodegradable and environmentally friendly
Effective thickener with near-neutral pH
Excellent foaming properties with low skin irritation
Highly compatible with various surfactant systems

Limitations

May form nitrosamines if used with nitrite-containing systems
Temperature-sensitive during formulation processes
Can cause color change or oxidation in finished products under improper pH conditions

Safety and Handling

Safety Aspect	Description
Skin contact	Generally non-irritant; use gloves for prolonged contact
Inhalation	Stable and non-volatile in liquid form; no vapor hazard
Eye contact	May cause mild irritation at high concentration; rinse immediately with water
Flash point	> 200°C
Storage	Store in HDPE or chemical-resistant plastic containers, in a dry, cool environment
Chemical stability	Stable at pH 6–10; sensitive to strong oxidizing agents
Biodegradability	Readily biodegradable in aqueous environments

Summary

Soy Fatty Acid Diethanolamide (Soyamide DEA) is a versatile nonionic surfactant derived from renewable soybean oil, valued for its thickening, foaming, and stabilizing properties. Its biodegradability, mildness, and formulation versatility make it a preferred ingredient in detergents, personal care products, and industrial cleaners.