Unlocking the potential of Atlox™ 4917: A multifunctional solution in agrochemical formulations

Nathan Castro, Market Applications Specialist at Croda delves into new research surrounding Atlox 4917 and its innovative potential in diverse applications, explaining the benefits this provides to formulating for the agrichemical market.

In recent years, the agricultural industry has witnessed a notable evolution in agricultural formulations, driven by the demand for more effective and environmentally friendly products. This shift has led to the development of complex formulations, presenting various challenges. These challenges include the need to enhance the stability of formulations while accommodating high loads of active ingredients and multiple active ingredients with diverse physicochemical properties.

Seed treatments have emerged as an environmentally friendly approach to reducing agrochemical usage. Their direct contact with the target site allows for the application of smaller doses of active ingredients compared to foliar applications. Additionally, seed treatments minimise potential exposure to non-target organisms as the seeds are embedded into the soil. Common treatments include the application of fungicides and insecticides.

A critical factor in the success of seed coating is the binder, which promotes the adherence of active ingredients to the seed surface. Accuracy in selecting components is essential to ensure the proper adherence under mechanical stress, preventing dust-off release, and maintaining abrasion performance without compromising flowability and germination.

However, majority of film-formers currently employed are microplastics, which raises concerns regarding their environmental impact. The persistent nature of microplastics in the environment and their potential to accumulate in soil and water ecosystems highlight the crucial need for more sustainable so alternatives. Additionally, as seed treatment formulations incorporate multiple active ingredients, there is limited space available for additional components. This necessitates the use of efficient and multifunctional additives to maintain formulation stability and efficacy.

What is Atlox 4917?

A few years ago, Croda introduced the dispersant Atlox 4917, designed to integrate electrostatic and steric stabilisation mechanisms, as illustrated in Figure 1.

Figure 1: Structure of Atlox 4917

This allows Atlox 4917, acting as a dispersant, to highlight the positive effects of both stabilisation mechanisms. Consequently, Atlox 4917 offers several unique benefits, including:

Electrolyte tolerant
Crystal growth control
Compatibility with a wide range of active ingredients
Effective at low use rate

Recently, it has come to light that Atlox 4917 exhibits even greater versatility than initially anticipated. In addition to its role as a dispersant, it has shown efficacy as a film-former in seed treatment formulations and promises to be an alternative that reduces or even eliminate the need for block co-polymers. This expanded functionality highlights the nature of Atlox 4917, positioning it as an excellent alternative for reducing formulation complexity by minimising the number of components required in the formulation.

Atlox 4917 seed binder properties

Atlox 4917, with its seed binder properties, exhibited performance comparable to other binders in conducted tests. Currently available on the market as an aqueous dispersant, Atlox 4917 falls outside the scope of EU microplastic legislation due to its water solubility. Furthermore, data indicates its versatility as a dispersant agent and binder, rendering it attractive for seed treatment formulations.

Fipronil was selected as the active ingredient for further investigation due to its widespread availability in the seed treatment market. Four formulations were prepared, comparing different binders used in seed treatment formulations (FS). The amount of the binders was adjusted to represent 4% of the solid content for each binder. The ‘Atlox 4917 solo’ formulation evaluated Atlox 4917 for its multiple functions as a dispersant and binder.

The formulations in Table 1 were evaluated using test methods to analyze the performance of the seed treatment. Presented here is a selection of data detailing the observations for the performance of maize insecticide treatment.

Table 1: FS formulations comparing different binders with a binderless formulation. The amount of the binders was adjusted to represent 4% of the solid content for each binder.

Dust-off testing quantifies the amount of dust released from treated seeds. Seeds undergo testing in a Heubach Dustmeter, where they circulate gently within a small drum while an air stream captures dust particles on a fiberglass filter. This method assesses the shedding of seed treatment, including active ingredients or components, as dust. Ideally, seed treatments should exhibit high abrasion resistance and minimal dust loss. In the dust-off evaluations for all treatments, no significant statistical difference was observed as shown in Figure 2.

Figure 2: Dust-off test for maize seeds using FS formulations (Fipronil 250 g/L). Means that do not share a letter are significantly different

The flowability test is conducted to assess the reduction in flow caused by the seed treatment. The presence of components leads to increased seed attrition after treatment compared to untreated seeds, resulting in decreased flowability. This reduced flowability may lead to delays in the packaging process or equipment clogging during packaging or sowing of treated seeds.

In Figure 3, all seed treatments using the Fipronil 250 g/L formulations are presented, comparing them with untreated seeds. All treatments exhibited good performance in the flowability test, with the Atlox 4917 solo notably achieving higher values compared to the other treatments.

Figure 3: Flowability test for maize seeds using FS formulations (Fipronil 250 g/L). Means that do not share a letter are significantly different (case sensitive)

The germination test was conducted to assess any potential phytotoxic effects or other factors that could lead to a reduction in the germination rate due to the components of the formulation. For this reason, the germination test was not conducted using a mixture of agrochemicals. This decision was made to prevent any artifacts that might arise from the components of other formulations and their active ingredients, which could potentially mask the intended purpose of the experiment.

No differences were observed among the treatments for the maize evaluated, as shown in Figure 4. However, a slight improvement in the number of germinated seeds was observed with the ‘Atlox 4917 solo’ treatment compared to the others, suggesting that reducing the number of components in a seed treatment formulation may enhance seed treatment performance.

Figure 4: Germination test for maize seeds using FS formulations (Fipronil 250 g/L)

Combine dispersant and milling aid properties

Exploring the multifunctional property of Atlox 4917 as a dispersant and milling aid, Atlox 4917 was compared to the industry benchmark, Atlox 4913 (dispersant) and Atlas G-5002L (wetting agent), for suspensions concentrated (SC) formulations using Chlorothalonil as the active ingredient as shown in Table 2.

Table 2: SC formulations comparing multifunctional property of Atlox 4917 to industry benchmark

Figure 5: Accelerated stability assessment of the Chlorothalonil 720 g/L SC

Both formulations, the benchmark and Atlox 4917, as a multifunctional component, demonstrated good performance in the accelerated stability test, as shown in Table 3. Additionally, the formulation containing only Atlox 4917 showed no alterations in pH and minimal viscosity variation in the product.

Table 3: Physicochemical data of Chlorothalonil SC formulations after accelerated storage stability

Agrochemical formulations are becoming increasingly complex, incorporating features such as multiple active ingredients and higher loading levels, requiring more versatile components to address various challenges encountered in development. Atlox 4917, a well-established technology launched by Croda, a few years ago, may serve as an excellent alternative for these situations, as it has been shown to be suitable not only as an aqueous dispersant but also as a binder for seed treatment and a promising alternative to reduce or eliminate the use of block copolymer. Additionally, Atlox 4917 falls outside the scope of EU microplastic legislation due to its water solubility, contributing to sustainable development.

This article is published in AgroPages' '2024 Formulation & Adjuvant Technology' magazine, check it out here.