iFormulate: Emulsifiable Concentrates (EC) – The Future of Agrochemical Formulation?

Date:04-29-2020

There can be little doubt that in all markets, not just agrochemicals, there is a drive to more sustainable and environmentally-friendly products.

Delivering products with these claims has been hampered by a number of different factors. Whilst the definitions of sustainability in particular has been helped by the publication of the United Nations Sustainable Development Goals, there remains a significant hurdle in all markets, namely do the new products still work, both functionally and economically?

In agrochemicals the Emulsifiable Concentrate (EC) formulation is a traditional formulation type and is in essence a very simple formulation consisting mainly of the active ingredient, a solvent and an emulsifier system which helps to provide the instant emulsification when the product is added to the spray tank. The manufacture of EC formulations is also very simple with little specialised equipment required and conventionally involves simply dissolving the active ingredient in the appropriate solvent and then adding the emulsifier under agitation. Final tests include simple appearance, assays to verify concentration, specific gravity, viscosity and emulsification checks. CIPAC methods are available for all of these¹.

This formulation type seemed an obvious target for replacement due to the use of unfavoured aprotic solvents such as N-methyl pyrollidone (NMP), dimethyl sulfoxide (DMSO) and flammable aromatic solvents such as xylene and the heavy aromatics often referred to by the ExxonMobil brand name of Solvesso.  The demise of this formulation was predicted by many but has this actually happened?

If we look at the EC format and its frequency of use in the Pesticides Manual, then in 2013, there were 339 actives listed as being formulated as an EC, in 2016, we reported²  that there were 459 active ingredients that were stated as being available in the EC format and that was the highest number of all the formats quoted. A similar search carried out in December 2019 showed that there were 477 active ingredients listed as being formulated as an emulsifiable concentrate.

Of course, this only relates to the number of active ingredients and not necessarily the value of the formulation type. In 2017, Matthew Phillips (then of Phillips McDougall) presented³ data  which showed the market value of different formulation types between 1992 and 2014. Whilst EC was the most valuable formulation type in 1992 with 35% market share, the share had dropped to just over 25% in 2014, but it was however still the most valuable formulation type. As part of an forthcoming report⁴ , we recently accessed the Agraspire database⁵  from 2018 to look at the share in value of the various formulation types and again found that EC still represented a large proportion of the value of products sold with the 23% market share just being below the 25% represented by sales of Suspension Concentrates (SC) formulations.

So why have we not seen the demise of the EC formulation? There is no single reason for this but we have speculated on a number of the possible explanations.

Firstly, the solvents have evolved and even with the Solvesso types the use of naphthalene depleted (ND) grades has become commonplace and this allows these grades and normally formulations not to require the H351 hazard statement “suspected of causing cancer”. Looking at one of the more popular herbicides, formulated as an EC, namely clethodim, we can see that new products such as UPL’s Shadow® 3EC still includes a heavy aromatic naphtha solvent (CAS 64742-94-5) but with a low level of naphthalene so is likely to be using a naphthalene depleted grade.

Of course, there have also been a number of new “greener” solvents coming onto the market which have claimed to be equivalent to the traditional solvents. One of the earliest families to be promoted for this application was the Rhodiasolv® range now being sold by Solvay, but there are also products such as the Armid® family from Nouryon, Corbion’s Purasolv® range and vegetable oil methylated esters from companies such as Croda to name but a few. To promote their equivalence to the more traditional solvents, the use of Hansen Solubility Parameters (HSP) is often used and this approach does demonstrate the technical feasibility of using these solvents but cannot cover other aspects such as level of active ingredient, emulsifiability and perhaps most importantly cost. This cannot be underestimated as the main EC products are all large volume - with many out of patent - so margins will be tight. Unless there is a regulatory requirement to remove heavy aromatic solvents then the cost of a new solvent must be close to that of the traditional solvents.  

A further indication that this formulation type will still be with us for a long time is the research activity as measured by academic and patent literature. As a further part of our work on the new report we found 21 WO patents in the main AO1N category which covers agrochemicals and included “Emulsifiable Concentrate” in the title or abstract and published since January 2016. Similarly, a search for the term in the title or abstract of academic literature yielded 26 results. So, whilst this is not the most active area for research in agrochemicals, it is certainly far from dead.

In summary, reports of the death of the Emulsifiable Concentrate are not to be believed and this is, and will remain, a valuable and significant formulation type due to its wide applicability, technical efficacy and cost effectiveness.

Reference:

1. https://cipac.org/index.php/methods-publications
2. Agrow Formulations 2016 (Informa Agrow)
3. Matthew Phillips Presentation at Informa Crops and Chemicals in Berlin 2017
4. Agribusiness Intelligence: Agrow Formulations 2020 (to be published)
5. https://agribusinessintelligence.informa.com/products-and-services/data-and-analysis/phillips-mcdougall/agraspire

This article will be published in AgroPages '2020 Formulation & Adjuvant Technology ' magazine to be published this May. 

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