Agrochemical formulations are commonly supplied to the end user as a concentrate which is then diluted for use. Adjuvant and agrochemical actives can be added in the tank mix at the point of dilution. However, preferably the adjuvants and actives are included in the concentrate. When the agrochemical active ingredient is insoluble or only partly soluble in water, the concentrate comprising the active is conveniently supplied in the form of a suspension concentrate (SC) in which finely divided solid particles of agrochemical are suspended in an aqueous formulation. Wetting agents and dispersants may also be including in the SC to wet and stabilise the solid particles. SC formulations may therefore typically comprise a solid active, surfactant, density/viscosity modifier system, freeze/thaw additive, bactericide, anti-foamer, and water diluent.
It is important that the solid particles remain suspended in the concentrate formulation without significant separation over an extended period of time under typical storage conditions. It is also important to prevent the dispersed solid particles in the SC from forming a hard pack sediment upon storage. It is therefore normally necessary to incorporate suspending or structuring agents in to the suspension concentrate. For example, existing structuring agents used for water-based SCs include polysaccharide gums, clays, celluloses, polyacrylates, and xantham gum.
The presence of high loadings of adjuvant in an SC formulation with consequent reduction in water content (both of which are highly desirable from efficacy and efficiency perspectives) present the formulator with major problems. Existing structuring agents are limited to the need for water in order to swell properly and provide adequate thickening to support a typical SC. The higher the amount of adjuvant that is included, in order to provide desired bioperformance, the more difficult it becomes to achieve a stable suspension concentrate. This problem is noted in US 2004/0082481.