Revolutionary Nanotechnology to Produce Future Agrochemical Formulations

Hans Kißwetter

Manager Businessfield Agrochemicals, NETZSCH-Feinmahltechnik GmbH

Research is being conducted around the world to better understand the effects of nanoparticles on people and the environment. 

Modified formulations of traditional pesticides, growth regulators and seed treatments are among the first nano-chemicals that could be used in agriculture. The greatly reduced particle size compared to conventional pesticides and the associated increase in surface area cause a fundamental change in the physico-chemical properties of nano-pesticides. Compared to larger particles of the same chemical substance, nanoparticles are more reactive, more biologically active and have a stronger catalytic effect. The use of nanoparticles could make pesticides more effective. Nanocapsules that release active ingredients in a targeted manner can also be used more sparingly with the same effect. That's why manufacturers of agrochemicals want to reduce the components of their products to nano-size or package the active ingredients in nano-capsules that only open under very specific conditions such as heat, sunlight or the alkaline environment inside an insect's stomach. Nanoparticles are intended to ensure that pesticides and fertilizers can be used more effectively.

Definition of Nanotechnology in Agrochemicals

Nanotechnology is the design and production of extremely small particles with structure sizes in general of up to 100 nanometers.

For nano-suspension formulae, there is actually no specific definition of the particle size range. However, similar to pharmaceuticals, printing inks, coatings and materials for the microelectronics or battery industry (see Fig. 1), in most cases the nanomaterials used for agrochemicals currently have particle sizes below one micrometer (d99), while for a traditional agrochemical suspension concentrate formula, the particle size requirement is around d90 = 5 - 10 micrometer.

Fig. 1: Nanoparticle

The Aim to Use Nano Particles in Agriculture Industry

Nanotechnology is one of the most revolutionary technologies for the coming years, but why do we still not have practical results in agriculture with the use of this technology as we have in medicine, industry, and other sectors?

Nanotechnology is the synthesis and processing of structures and devices with control at the molecular level which can be used to improve and optimize the physical and chemical properties of any material.

We can use nanotechnology in agriculture for many applications such as

1. smart coatings that release fungicide/insecticide for seed care

2. nanocapsules for controlled release of agrochemicals, biologicals and fertilizers

3. nanoencapsulation of biologicals

4. intelligent sensors for soils, plants and zoonoses 

5. antibacterial coatings for fruits and smart packaging

The use of nanoparticles in agrochemical products is aimed at increasing the efficiency and sustainability of agricultural production by optimizing the use of chemicals while minimizing environmental impact.

The Top-down Process to Produce Nanoparticles for Agrochemicals

The ″Top-down Synthesis Process″ is a process technology used to produce nanoparticles for agrochemical products by breaking down larger structures into smaller ones. This technique offers several advantages for the production of nanoparticles in agrochemicals, including:

• Control over size and shape

• Scalability

• Versatility

• Reduced impurities

• Energy efficiency

Wet Grinding Technology for Top-Down Processes

As ultrafine dispersed powders are extremely reactive elements and consequently pose a very high risk of dust explosion in dry fine grinding processes, very high safety standards must be established to ensure the safety of the process operator and the environment.

Therefore an elementary conclusion for further process design for the grinding of nano-formulations in agrochemicals is to proceed with wet processing technology (see Fig. 2)!

Fig. 2: Classification of comminution processes for nano-scale products

Wet fine grinding processes (e.g. for SC formulations) consisting of a raw material feed station and mixing tank for preparation of the product suspension and, in a parallel step, the thickening agent, with the grinding stage carried out in an agitator bead mill and various product containers, etc., offer the following decisive advantages

Particle size Reduction:

-Finer particles

-Better homogeneity

Cooling and reduced heat generation:

-Heat dissipation

-Preventing of decomposition

Less dust and improved safety:

-Dust reduction

-Fire and explosion hazards

Energy efficiency:

-Lower energy consumption

Better material handling:

-Flow properties

-Continuous processing

Chemical reactivity:

-Enhanced chemical reactions

Surface chemistry and morphology:

-Surface modification

In agrochemical applications, wet grinding is crucial for the preparation of nanopowders and dispersions, ensuring consistent formulations.

NETZSCH NEOS Agitator Bead Mill – for Nanogrinding with Maximum Production Rates

Media milling – or grinding – is the most well-established manufacturing method

for nanoparticle production. Stirred media mills are used in many different industries

to reduce particle size and to develop higher-quality products because of this equipment.

Nano grinding with a stirred media mill offers the key benefits:

• excellent particle size control

• comparative cost effectiveness

• equipment scalability, from benchtop to production

• process repeatability

Figure 3 shows the NETZSCH NEOS agitator bead mill, perfectly designed for grinding nanoparticles in agrochemical applications The system creates grinding and dispersion by agitating the beads with the pins or pegs on the agitator shaft.

Uniform compression throughout the chamber’s length is key to this process. This concept results in total utilization of the media charge and mill capacity for greater efficiency in particle size reduction

Fig. 3: Design of NETZSCH NEOS Agitator Bead Mill

The agitator bead mill with the newly-developed NEOS grinding system stands for maximum performance, product quality and efficiency. Coupled with the reliable use of extremely small grinding media, you can achieve your required product quality with high production output and low specific energy consumption (see Fig. 4).

Fig. 4: Progress in PSD related to specific energy input for a nano insecticide

The importance of stable formulations for the nanogrinding of agrochemicals 

Reagglomerated nanoparticles can cause significant problems in agrochemical applications, affecting product efficacy and handling. The most common stabilization method in the production of agrochemical nanoparticles is surface modification using polymers or surfactants. (see Fig. 5). 

This method often combines steric stabilization with electrostatic stabilization. Nanoparticles can be coated with a layer of polymers, surfactants or other stabilizing molecules. This layer prevents the nanoparticles from clumping together through steric hindrance or electrostatic repulsion and is often used to keep the nanoparticles stable and optimize their properties for specific agricultural use.

Fig. 5: Illustration of an adsorbed polymer layer

SUMMARY

Nanotechnology – the design and production of extremely small particles with structure sizes below 100 nanometers – is met with interest and, at the same time, skepticism. Research is being conducted around the world to better understand the effects of nanoparticles on people and the environment. The potential applications of nanoparticles are diverse: for example in electrical and energy technology, in consumer goods such as textiles, but also in medicine, in the food sector and in agriculture or agrochemical industry. National and international researchers are devoting a great deal of time and capacity to nanotechnology and are developing the basis for assessing its opportunities.

NETZSCH, as a manufacturer of machines and complete processes has the know-how of the production of nanoparticles for agrochemical applications. Our machine scope from laboratory machines to complete process lines or turn-key plants allow our customers to get complete solutions from single source.

Biography Hans Kißwetter

Hans Kißwetter

Manager Businessfield Agrochemicals

NETZSCH-Feinmahltechnik GmbH

Sedanstraße 70

D-95100 Selb/Bavaria

Telephone: + 49 9287 797-203

Telefax: + 49 9287 797 149

Mobil: + 49 172 88 12 060

e-mail: hans.kisswetter@netzsch.com

1991     Study mechanical engineering at Technical University Munich, Germany

1997     Mechanical Engineer product design at Krauss-Maffei Munich, Germany

1998     Mechanical Engineer product design at HAMM AG, Germany

2002     Technical support engineer at NETZSCH-Feinmahltechnik GmbH in Selb, Germany

2004     Sales engineer for East Europe and Russia at NETZSCH- Feinmahltechnik GmbH in Selb, Germany

2016     Global Manager Application Field Agrochemiclas for NETZSCH- Feinmahltechnik GmbH in Selb, Germany