Concentrated aqueous emulsion (EW)
They can be considered as a safer and more environmentally friendly alternative to emulsifiable concentrates (EC). In an EW the continuous phase is water (as opposed to an organic solvent for ECs) which offers the benefit of lower phytotoxicity, no flashpoint concern, ease of handling, and a lower environmental impact.
EW formulations are physically stabilised by specifically identified polymeric surfactants incorporated at an appropriate level. The emulsion has already been established in the formulation and is only diluted further in the spray mixture.
Benefits
- Simple to manufacture
- Relatively high biological activity
- Good chemical stability
- Spontaneous emulsification upon dilution
Limitations
- Use expensive solvents containing harmful VOCs
- Solvents may affect plastics and rubbers in spray applicators
- Active ingredients needs to be fully soluble in the solvent over a range of temperatures
- Use of water miscible solvents can cause active ingredient crystallisation problems upon dilution
The Formulator's Toolbox (Full Version)
Products recommended for EW
We recommend the combination of a low and high HLB polymeric surfactant to obtain EW formulations with excellent, long term stability. This surfactant combination ensures that the formulation maintains stability over a range of application temperatures.
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Atlas™ G-5004 LD
A demineralised version of Atlas™ G-5002L. It is used as a high HLB emulsifier for active ingredients that are sensitive to mineral presence.
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Atlas™ G-5002L
A high HLB polymeric emulsifier or wetting agent in liquid form providing long term stability. It is commonly used in combination with Atlox™ 4916 for emulsions or Atlox Metasperse 500L for...
Tween™ 22
A high HLB emulsifier and adjuvant applicable for both built-in and tank mix applications. The significantly reduced equilibrium surface tension compared to Tween 20 gives the product excellent spray...
Tween™ 23
A high HLB emulsifier and adjuvant applicable for both built-in and tank mix applications. Improved performance identified with various hydrophilic herbicides.
Tween™ 24
A high HLB emulsifier and adjuvant applicable for both built-in and tank mix applications. Strong all round performing adjuvant and strategic emulsifier for use with low HLB partner in microemulsions
We recommend the combination of a low and high HLB polymeric surfactant to obtain EW formulations with excellent, long term stability. This surfactant combination ensures that the formulation maintains stability over a range of application temperatures.
Atlox™ 4916
A low HLB polymeric emulsifier and non-aqueous dispersant, with a unique star structure, which provides exceptional stability. As an emulsifier it is commonly used in combination with Atlas™ G-5002L.
Atlox™ 4914
A nonionic random polymeric surfactant with low HLB value which can be used as an emulsifier or non-aqueous dispersant. Multiple PEG anchoring groups allow for good long term stability in complex...
In an EW formulation the active ingredient must be fully soluble in the carrier solvent. If the active ingredient is solid, it will need to be dissolved in a solvent. Croda’s Seatons Natural Oil range are 100% natural and renewable, which make them a great choice for use in crop care formulations.
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Seatons refined linseed oil
Seatons refined linseed oil is a simple and effective alternative to mineral oil. It is non-flammable, impurity free and has good compatibility with many agrochemical active ingredients. Natural oils...
Seatons refined rapeseed oil
Seatons refined rapeseed oil is a simple and effective alternative to mineral oil. It is non-flammable, impurity free and has good compatibility with many agrochemical active ingredients. Natural oils...
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Seatons refined soyabean oil
Seatons refined soyabean oil is a simple and effective alternative to mineral oil. It is non-flammable, impurity free and has good compatibility with many agrochemical active ingredients. Natural oils...
If an EW is not properly structured, the formulation can breakdown resulting in the oil phase creaming to the surface. This leads to reduced shelf life stability and poor performance in the field. The inclusion of a rheology modifier helps overcome this issue by increasing the viscosity of the formulation, providing improved stability.
Atlox Rheostrux™ 300A
Rheology modifier designed for aqueous formulations. Excellent performance seen in acidic conditions necessary for certain active ingredients. Supplied in liquid form for easy addition via stirring...
