Crop Care
Concentrated aqueous emulsion (EW) formulations are stable emulsions of an insoluble liquid in a continuous water phase. The insoluble liquid can be either a liquid active ingredient or a solid active ingredient dissolved in a solvent.
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 of expensive solvents containing harmful VOCs
- Solvents may affect plastics and rubbers in spray applicators
- Active ingredients need to be fully soluble in the solvent over a range of temperatures
- Crystallisation of active ingredient if solvent is too polar or slightly soluble in water