Polyethyleneglycol Fatty Acid Ester Surfactants
PEG Ester surfactants are manufactured by reacting a polyethylene glycol with a fatty acid. The polyethylene glycol comprises the hydrophilic part of the surfactant and the fatty acid the lipophilic part. By varying the molecular weight of the PEG and the fatty acid, surfactants covering a wide range of HLB values can be produced. Typically, those with an HLB below 13 are oil soluble and water dispersible while those above are water soluble.
EMULSIFICATION : PEG esters, particularly PEG oleates and stearates, are excellent emulsifiers, better than alcohol ethoxylates or nonyl phenol ethoxylates.
FOAMING: Low foaming tendency
WETTING/DISPERSING: Good wetting/dispersing properties
LOW TOXICITY: Widely used in cosmetics and toiletries
BIODEGRADABILITY: Readily biodegradable
LOW HAZARD: No hazard labelling required for transport or use.
STABILITY: Hydrolysed under hot alkaline conditions.
The traditional application areas for PEG ester surfactants have mainly utilised their excellent water/oil emulsifying properties, e.g. as: Lubricants in textile processing Cutting oils and metalworking fluids Solvent cleaners and emulsifiable degreasers Emulsifiers for self-emulsifying herbicides, insecticides and fungicides Emulsifiers for cosmetic creams and toiletry emulsions Emulsifiers for polymer latex production
Other applications have utilised their wetting/dispersing properties, e.g. as: Pigment dispersants for both organic and inorganic pigments in aqueous and non-aqueous systems. Plasticizers/viscosity modifiers in mastics, adhesives, emulsion paints and PVC plastisols
PEG Esters as Alternatives to Nonylphenol Ethoxylates
The environmental effects associated with NPE’s are now well documented and their replacement by alternatives is being strongly encouraged.
It is considered that PEG oleate surfactants are a closer match to NPE’s with respect to solubility and emulsifying characteristics than are alcohol ethoxylate surfactants.
The attached table lists a series of PEG Oleates and their corresponding NPE’s based on HLB No. Tables are also included comparing PEG cocoate and stearate surfactants with their corresponding alcohol ethoxylates.