WO2021250383A1 - Clay compositions - Google Patents

Clay compositions Download PDF

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Publication number
WO2021250383A1
WO2021250383A1 PCT/GB2021/051405 GB2021051405W WO2021250383A1 WO 2021250383 A1 WO2021250383 A1 WO 2021250383A1 GB 2021051405 W GB2021051405 W GB 2021051405W WO 2021250383 A1 WO2021250383 A1 WO 2021250383A1
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Prior art keywords
clay
particle gel
laponite
weight
particle
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PCT/GB2021/051405
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French (fr)
Inventor
Camille BOULET
Dirk Gerard Albert Louis AARTS
Carl Andrew Formstone
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Oxford University Innovation Limited
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Publication of WO2021250383A1 publication Critical patent/WO2021250383A1/en

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    • A—HUMAN NECESSITIES
    • A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
    • A01N—PRESERVATION OF BODIES OF HUMANS OR ANIMALS OR PLANTS OR PARTS THEREOF; BIOCIDES, e.g. AS DISINFECTANTS, AS PESTICIDES OR AS HERBICIDES; PEST REPELLANTS OR ATTRACTANTS; PLANT GROWTH REGULATORS
    • A01N25/00—Biocides, pest repellants or attractants, or plant growth regulators, characterised by their forms, or by their non-active ingredients or by their methods of application, e.g. seed treatment or sequential application; Substances for reducing the noxious effect of the active ingredients to organisms other than pests
    • A01N25/02—Biocides, pest repellants or attractants, or plant growth regulators, characterised by their forms, or by their non-active ingredients or by their methods of application, e.g. seed treatment or sequential application; Substances for reducing the noxious effect of the active ingredients to organisms other than pests containing liquids as carriers, diluents or solvents
    • A01N25/04—Dispersions, emulsions, suspoemulsions, suspension concentrates or gels

Definitions

  • the invention provides a particle gel.
  • the invention also provides a composition for use in agriculture, wherein the composition is obtainable by diluting a particle gel as described herein with water.
  • the invention also provides an agrochemical formulation.
  • Thickening and rheological agents have applications in a wide variety of fields, including paints, cosmetics, pharmaceuticals and agrochemicals. In certain applications, it is useful to add thickening agents that are able to maintain a stable gel structure during storage.
  • the composition comprises a dispersion of insoluble particles or emulsified active ingredients which may settle (or cream) out of suspension over time.
  • the composition can be kept as a stable gel for several months at least with a substantially even dispersion of insoluble active ingredients.
  • the product containing the thickening agents may require further processing before it is used.
  • the composition may require diluting or mixing with further ingredients.
  • shear thinning non- Newtonian behaviour
  • the Xanthan/bentonite system is not effective in compositions with a higher ionic strength, such as compositions in which a soluble salt form of an active ingredient is dissolved. It would therefore be advantageous to develop thickening agents which provide the useful rheological properties of known compositions, but which also overcome the drawbacks in terms of cost, bacterial contamination and compatibility with surfactants and higher ionic strength (salt-containing) compositions at varying pH.
  • compositions of this type overcome the aforementioned disadvantages with formulating soluble salts of active ingredients.
  • insoluble active ingredients e.g. particles or emulsions
  • insoluble active ingredients can also be added which remain in stable suspension.
  • compositions of the invention are based on largely inorganic clay materials as thickening agents, the risk of bacterial degradation mentioned above is avoided in this regard.
  • the compositions of the invention have lower manufacturing costs and an increased shelf-life, whilst still maintaining the desired rheological properties (elastic and loss moduli, viscosity and yield stress) as known Xanthan/bentonite compositions. This is useful in agrochemical applications where a product may be stored for some time prior to dilution and use (e.g. as a crop spray).
  • the compositions of the invention provide the desired rheological properties at ionic strengths which permit the incorporation of additional soluble ingredients in salt form as well as the addition of desirable surfactants.
  • compositions of the invention open up new possibilities in terms of new combinations of active ingredients and could contribute to the new products containing new active substances.
  • the present invention may also find use in other fields such as pharmaceutics, food, cosmetics and paint, where particular rheological properties are desired.
  • the invention therefore provides a particle gel comprising particles of a first clay, particles of a second clay and a liquid phase, wherein the second clay is different from the first clay and the second clay comprises an organic modification.
  • the invention also provides a process for producing a composition for use in agriculture, which process comprises diluting a particle gel as described herein with water.
  • the invention also provides a composition for use in agriculture, wherein the composition is obtainable by diluting a particle gel as described herein with water.
  • the invention also provides a composition comprising a bentonite clay and a hectorite clay, wherein the hectorite clay comprises an organic modification.
  • the invention also provides an agrochemical formulation comprising
  • a hectorite clay which comprises an organic modification (a) a hectorite clay which comprises an organic modification, and (b) one or more active ingredients, wherein at least one of the active ingredients is an agrochemical.
  • the invention also provides the use of a particle gel as described herein, a composition as described herein, or an agrochemical formulation as described herein, as a plant protection product.
  • Figures 1 and 2 show flow ramp results for azoxystrobin SC #1 using LaponiteTM EP 5g/L BentopharmTM B20 15 g/L, or LaponiteTM EP 5g/L BentopharmTM B2020 g/L as thickener in the presence of an anionic dispersant.
  • Figure l is a plot of stress (Pa) vs shear rate (s -1 )
  • Figure 2 is a plot of viscosity (Pa.s) vs shear rate (s -1 ).
  • Two tests (called 1st test and 2nd test) were carried out on two different samples both made the same way to determine the reproducibility of the results. The experiment on the second test was performed seven days after making the sample.
  • Figure 3 shows strain oscillation results for azoxystrobin SC #1 using LaponiteTM EP 5g/L BentopharmTM B20 15 g/L, or LaponiteTM EP 5g/L BentopharmTM B2020 g/L as thickener in the presence of an anionic dispersant as a plot of G’, G” (Pa) vs strain (%).
  • Two tests (called 1st test and 2nd test) were carried out on two different samples both made the same way to determine the reproducibility of the results. The experiment on the second test was performed seven days after making the sample.
  • Figure 4 shows frequency oscillation results for azoxystrobin SC #1 with LaponiteTM EP 5g/L BentopharmTM B20 15 g/L, or LaponiteTM EP 5g/L BentopharmTM B2020 g/L in the presence of an anionic dispersant as a plot of G’, G” (Pa) vs frequency (Hz). Data where d>90° are not taken into account.
  • Figure 5 shows flow ramp results for the storage study for azoxystrobin SC #1 with LaponiteTM EP 5g/L BentopharmTM 15 g/L or LaponiteTM EP 5g/L BentopharmTM 20 g/L (with anionic dispersant) which were stored for four weeks at 40°C, as a plot of stress (Pa) vs shear rate (s -1 ).
  • Figure 6 shows strain oscillation results for the storage study for azoxystrobin SC #1 with LaponiteTM EP 5g/L BentopharmTM 15 g/L or LaponiteTM EP 5g/L BentopharmTM 20 g/L (with anionic dispersant) which were stored for four weeks at 40°C, as a plot of G’, G” (Pa) vs strain (%).
  • Figures 7 and 8 show flow ramp results for azoxystrobin SC #2 (with non-ionic dispersant), azoxystrobin SC #1 (with anionic dispersant) and for an azoxystrobin SC#2 using LaponiteTM EP 5.5g/L BentopharmTM 20 g/L.
  • Figure 7 is a plot of stress (Pa) vs shear rate (s -1 );
  • Figure 8 is a plot of viscosity (Pa.s) vs shear rate (s -1 ).
  • Figure 9 shows strain oscillation results for azoxystrobin SC #2 with non-ionic dispersant (RhodopolTM 23 at 3 g/L, BentopharmTM B20 at 30 g/L, control number 2), azoxystrobin SC #2 with non-ionic dispersant (RhodopolTM 23 2 g/L, BentopharmTM B2025 g/L, control number 1), azoxystrobin SC #1 with anionic dispersant (RhodopolTM 23 2 g/L, BentopharmTM B2025 g/L) and for an azoxystrobin SC #2 using LaponiteTM EP 5.5g/L BentopharmTM B2020 g/L (with non-ionic dispersant) as a plot of G’, G” (Pa) vs strain (%).
  • RhodopolTM is a commercially available xanthan-based thickener.
  • Figure 10 shows frequency oscillation results for azoxystrobin SC #1 (formulation with anionic dispersant) and for an azoxystrobin SC #2 with non-ionic dispersant using LaponiteTM EP 5.5g/L BentopharmTM 20 g/L as a plot of G’, G” (Pa) vs frequency (Hz).
  • Figure 11 shows flow ramp results for the storage study on azoxystrobin SC #2 using LaponiteTM EP 5.5g/L BentopharmTM 20 g/L (with non-ionic dispersant) after storage for four weeks at 40°C as a plot of stress (Pa) vs shear rate (s -1 ).
  • Figure 12 shows strain oscillation results for the storage study on azoxystrobin SC #2 with LaponiteTM EP 5.5g/L BentopharmTM 20 g/L (with non-ionic dispersant) after storage for four weeks at 40°C as a plot of G’, G” (Pa) vs strain (%).
  • Figure 13 shows the results of an aging study on samples of LaponiteTM EP 2% (w/w) and LaponiteTM RD 5% (w/w) as plot of G’, G” (Pa) vs time (s).
  • Figure 14 shows the strain oscillation results for the pH study (samples of LaponiteTM EP 5g/L + BentopharmTM 20g/L at the unmodified pH of 8.96 and LaponiteTM EP 5g/L + BentopharmTM 20g/L adjusted to pH 4) as a plot of G’, G” (Pa) vs strain (%).
  • Figure 15 shows flow ramp results for the pH study (samples of LaponiteTM EP 5g/L + BentopharmTM 20g/L at the unmodified pH of 8.96 and LaponiteTM EP 5g/L + BentopharmTM 20g/L adjusted to pH 4) as a plot of stress (Pa) vs shear rate (s -1 ) (left hand side) and viscosity (Pa.s) vs shear rate (s -1 ) (right hand side).
  • Figure 16 shows the strain oscillation results for the pH study (samples of LaponiteTM RD 15g/L + BentopharmTM 20g/L at the unmodified pH of 9.67 and LaponiteTM RD 15g/L + BentopharmTM 20g/L adjusted to pH 4) as a plot of G’, G” (Pa) vs strain (%).
  • Figure 17 shows flow ramp results for the pH study (samples of LaponiteTM RD 15g/L + BentopharmTM 20g/L at the unmodified pH of 9.67 and LaponiteTM RD 15g/L + BentopharmTM 20g/L adjusted to pH 4) as a plot of stress (Pa) vs shear rate (s -1 ) (left hand side) and viscosity (Pa.s) vs shear rate (s -1 ) (right hand side).
  • Figure 18 shows strain oscillation results for LaponiteTM EP 5g/L + BentopharmTM 20g/L with various concentrations of MgCh as a plot of G’, G” (Pa) vs strain (%).
  • Figure 19 shows flow ramp results for LaponiteTM EP 5g/L + BentopharmTM 20g/L with various concentrations of MgCh as a plot of stress (Pa) vs shear rate (s -1 ) (left hand side) and viscosity (Pa.s) vs shear rate (s -1 ) (right hand side).
  • Figure 20 shows strain oscillation results for LaponiteTM RD 15g/L + BentopharmTM 20g/L with various concentrations of MgCh as a plot of G’, G” (Pa) vs strain (%).
  • Figure 21 shows flow ramp results for LaponiteTM RD 15g/L + BentopharmTM 20g/L with various concentrations of MgCh as a plot of stress (Pa) vs shear rate (s -1 ) (left hand side) and viscosity (Pa.s) vs shear rate (s -1 ) (right hand side).
  • Figure 22 shows strain oscillation results for LaponiteTM EP 5g/L + BentopharmTM 20g/L with various concentrations of Tween 20 as a plot of G’, G” (Pa) vs strain (%).
  • Figure 23 shows flow ramp results for LaponiteTM EP 5g/L + BentopharmTM 20g/L with various concentrations of Tween 20 as a plot of stress (Pa) vs shear rate (s -1 ) (left hand side) and viscosity (Pa.s) vs shear rate (s -1 ) (right hand side).
  • Figure 24 shows strain oscillation results for LaponiteTM RD 15g/L + BentopharmTM 20g/L with 1% or 10% Tween 20 as a plot of G’, G” (Pa) vs strain (%).
  • Figure 25 shows flow ramp results for LaponiteTM RD 15g/L + BentopharmTM 20g/L with 1% or 10% Tween 20 as a plot of stress (Pa) vs shear rate (s -1 ) (left hand side) and viscosity (Pa.s) vs shear rate (s -1 ) (right hand side).
  • Figure 26 shows strain oscillation results for the formulation of an azoxystrobin SC #1 (with anionic dispersant) using LaponiteTM EP as thickening agent either at 5g/L, lOg/L or at 5g/L in combination with BentopharmTM 20g/L as a plot of G’, G” (Pa) vs strain (%).
  • Figure 27 shows flow ramp results for the formulation of an azoxystrobin SC #1 (with anionic dispersant) using LaponiteTM EP as thickening agent either at 5g/L, lOg/L or at 5g/L in combination with BentopharmTM 20g/L as a plot of stress (Pa) vs shear rate (s -1 ) (left hand side) and viscosity (Pa.s) vs shear rate (s -1 ) (right hand side).
  • Figure 28 shows the strain oscillation results for LaponiteTM EP 5g/L, LaponiteTM EP lOg/L, Bentopharm 20g/L, Bentopharm 40g/L and LaponiteTM EP 5g/L + BentopharmTM 20g/L as a plot of G’ (Pa) vs strain (%) (top) and a plot of G” (Pa) vs strain (%) (bottom), from example 9.
  • Figure 29 shows the results of the flow ramp test results for LaponiteTM EP 5g/L, LaponiteTM EP lOg/L, Bentopharm 20g/L, Bentopharm 40g/L and LaponiteTM EP 5g/L + BentopharmTM 20g/L as a plot of stress (Pa) vs shear rate (s -1 ) (top) and viscosity (Pa.s) vs shear rate (s -1 ) (bottom), from example 9.
  • Figure 30 shows the stress versus strain rate curve (top) and the viscosity versus strain rate curve (bottom) for LaponiteTM EP combined with BentopharmTM as thickening agent against the control with RhodopolTM (xanthan) only, for gel containing copper-mesotrione, in example 10.
  • Figure 31 shows stress versus strain rate curve (top) and the viscosity versus strain rate curve (bottom) for LaponiteTM EP combined with AttagelTM as thickening agent against the control with RhodopolTM (xanthan) only, for gel containing copper-mesotrione, in example 10
  • Figure 32 shows G’ obtained during the strain oscillations for LaponiteTM EP combined with BentopharmTM as thickening agent compared to the control sample with RhodopolTM (xanthan) for gel containing copper-mesotrione, in example 10.
  • Figure 33 shows G’ during the strain oscillations for LaponiteTM EP combined with AttagelTM as thickening agent compared to the control sample with RhodopolTM (xanthan) for gel containing copper-mesotrione, in example 10.
  • Figure 34 presents the mass loss obtained from thermogravimetric analysis (TGA) for LaponiteTM EP and LaponiteTM RD in example 12.
  • Figure 35 shows the first heat flow curves from the differential scanning calorimetry (DSC) analysis for LaponiteTM EP and LaponiteTM RD in example 12. Note that for the heat flow curves, exotherms point upward.
  • DSC differential scanning calorimetry
  • Figure 36 shows the spectrum obtained from the CP-MAS 13C NMR of LaponiteTM EP, from example 13.
  • particle gel is known in the art, and takes its normal meaning herein.
  • a particle gel may be gel comprising a dispersed solid and/or liquid particle phase intertwined with a continuous liquid phase.
  • the particle gel is a gel comprising a dispersed solid particle phase intertwined with a continuous liquid phase.
  • a “house of cards structure” is known in the art, and takes its normal meaning herein.
  • the term refers to an extended network of particles linked by edge-edge, edge-face and face-face interactions.
  • House of cards structures are discussed in Luckham, Paul F., and Rossi, Sylvia. "The colloidal and rheological properties of bentonite suspensions", Advances in colloid and interface science 82.1-3 (1999): 43-92).
  • microparticle means a microscopic particle whose size is typically measured in micrometres (pm).
  • a microparticle usually has a particle size of greater than 0.1 pm, and more typically has a particle size of greater than 0.5 pm, preferably more than 1 pm.
  • the particle size of a microparticle is typically up to 1000 pm, typically up to 500 pm. Often, however, a microparticle has a particle size of from 1 to 100 pm.
  • nanoparticle means a microscopic particle whose size is typically measured in nanometers (nm).
  • a nanoparticle typically has a particle size of from 0.1 nm to 1000 nm, for instance from 1 to 750 nm or from 5 to 500 nm.
  • room temperature refers to the conventional definition of room temperature of between 15 and 25°C.
  • smectite as used herein is known in the art, and takes its normal meaning herein.
  • a smectite is a naturally occurring silicate-based mineral composed of four atomic planes of oxygen atoms that are cross-linked primarily by silicon in tetrahedral interstices and other metallic elements (e.g., lithium, magnesium, and aluminum) in the octahedral sites.
  • metallic elements e.g., lithium, magnesium, and aluminum
  • the residual negative charge on the layers is balanced by exchangeable hydrated cations (denoted Mn+,xH20) that reside in the gallery region between the layers (see T.J. Pinnavaia, in Encyclopedia of Materials: Science and Technology, 2001).
  • montmorillonite clay is a member of the smectite group, and is typically a 2:1 clay, meaning that it has two tetrahedral sheets of silica sandwiching a central octahedral sheet of alumina and is characterized as having greater than 50% octahedral charge.
  • Bentonite is an absorbent aluminium phyllosilicate clay comprising montmorillonite.
  • hectorite as used herein is known in the art, and takes its normal meaning herein. Thus, a hectorite clay may be found naturally. In the context of the present invention this term is also used to refer to both natural and synthetic forms of this type of clay (“synthetic hectorites”), for instance commercially available synthetic hectorite-type materials such as LaponiteTM, which is a type of “synthetic hectorite”.
  • synthetic clay as used herein is known in the art, and takes its normal meaning herein. Thus, the term refers to a clay synthesised by humans, rather than formed as the result of natural geological processes.
  • the present invention provides a particle gel comprising particles of a first clay, particles of a second clay and a liquid phase, wherein the second clay is different from the first clay and the second clay comprises an organic modification.
  • the particles of the first clay and the particles of the second clay form a house of cards structure.
  • the particles of the first clay and the particles of the second clay interact with each other to produce a single network formed from both types of clay particles.
  • the particles of the first clay are platelets and the particles of the second clay are platelets.
  • the particle gel may comprise a single network formed from both the particles of the first clay and the particles of the second clay, wherein the particles of the first clay are platelets and the particles of the second clay are platelets.
  • the particles of the first clay and the particles of the second clay may exhibit edge-edge, edge- face and/or face-face interactions.
  • the particles of the first clay and the particles of the second clay exhibit edge-edge, edge-face and face-face interactions.
  • the particle gel is a non-Newtonian fluid.
  • the viscosity of the particle gel usually decreases upon application of a force.
  • the particle gel is a shear-thinning fluid.
  • the particle gel may be thixotropic.
  • Thixotropic materials display time-dependent shear thinning behaviour. For instance, thixotropic materials take a finite time to attain equilibrium viscosity when introduced to a change in shear rate.
  • the yield stress of the particle gel is from 1 to 10 Pa, for instance from 1 to 5 Pa.
  • the particle gel has a yield stress of from 1 to 10 Pa, preferably from 1 to 5 Pa at room temperature.
  • the yield stress is the stress that must be applied to make the gel flow.
  • the skilled person would be well aware of a method for determining the yield stress of a composition. For instance, an approximate yield stress measurement can be gained by plotting the shear stress values for a range of shear rates, fitting a curve to the data, and extrapolating through the stress axis. The intersect on the stress axis gives the yield stress. It may be useful to use a rheological mathematical model, such as the Casson model (see Rao, M. Anandha. "Flow and functional models for rheological properties of fluid foods.” Rheology of fluid, semisolid, and solid foods. Springer, Boston, MA, 2014. 27-61).
  • the infinite viscosity of the particle gel determined using a fit of the stress vs strain rate curve using a Casson model is less than 100 mPa.s.
  • the infinite viscosity of the particle gel determined using a fit of the stress vs strain rate curve using a Casson model may be less than 75 mPa.s, less than 50 mPa.s or less than 25 mPa.s.
  • the infinite viscosity of the particle gel determined using a fit of the stress vs strain rate curve using a Casson model is at least 1 mPa.s, for instance at least 5 mPa.s.
  • the infinite viscosity of the particle gel determined using a fit of the stress vs strain rate curve using a Casson model is between 1 and 100 mPa.s, for instance between 1 and 50 mPa.s, preferably between 5 and 25 mPa.s. Unless mentioned otherwise, all infinite viscosity values refer to the infinite viscosity at room temperature, as defined herein.
  • the particle gel of the invention displays a particular viscosity at a particular shear rate.
  • the viscosity of the particle gel of the invention can readily be modified by subject in it to a specific shear rate. This might be useful when the particle gel is mixed with further ingredients or diluted.
  • the viscosity values refer to the viscosity at room temperature, as defined herein.
  • the viscosity of the particle gel at a shear rate of 20 s -1 is less than 450 mPa.s, preferably less than 420 mPa.s.
  • the viscosity of the particle gel at a shear rate of 10 s -1 is less than 700 mPa.s, preferably less than 500 mPa.s.
  • the particle gel may be a particle gel that exhibits a viscosity of less than 420 mPa.s at a shear rate of 20 s -1 and of less than 700 mPa.s at a shear rate of 10 s -1 .
  • the elastic modulus G' of the particle gel is between 10 and 50 Pa, preferably between 10 and 40 Pa.
  • the critical strain (ycritic) of the particle gel is typically between 0.005 and 0.1 (0.5% and 10%), for instance between 0.005 and 0.05 (0.5 and 5%), typically between 0.005 and 0.02 (0.5 and 2%).
  • the critical strain (ycritic) of the particle gel is about 0.01 (about 1 %).
  • the elastic modulus G’ and the critical strain may be determined on the linear viscosity range whose the limit was found using the Lissajous (torque vs displacement) plot or applying a 5% threshold compared to the value obtained in the linear viscoelastic range. Unless mentioned otherwise, the viscoelasticity properties are measured at room temperature, wherein room temperature is as defined herein.
  • Determination of the viscosity parameters discussed above may be performed using a controlled stress rheometer.
  • the yield stress and the infinite viscosity may be determined by doing a flow ramp and fitting the curves with a Casson model (see Rao, M. Anandha. "Flow and functional models for rheological properties of fluid foods.” Rheology of fluid, semisolid, and solid foods. Springer, Boston, MA, 2014. 27-61).
  • the flow ramp up curve was fitted with the Casson model to determine the infinite viscosity and the yield stress.
  • the flow ramp up curve is measured at increasing shear speeds from 0 to 600 s -1 .
  • the viscosity at a particular shear rate may be determined by looking at the values obtained during the flow ramp up at such a shear rate.
  • the elastic modulus G’ and critical strain may be determined by performing a strain oscillatory test.
  • the linear viscoelastic range may be determined using the Lissajous plot and/or the 5% threshold.
  • the particle gel according the invention fulfils at least two of the following criteria, for instance at least three of the following criteria, at least four of the following criteria or at least five of the following criteria: the yield stress of the particle gel is from 1 to 10 Pa; the infinite viscosity of the particle gel determined using a fit of the stress us strain rate curve using a Casson model is less than 100 mPa.s; the viscosity of the particle gel at a shear rate of 20 s -1 is less than
  • the viscosity of the particle gel at a shear rate of 10 s -1 is less than 700 mPa.s; the elastic modulus G' determined on the linear viscoelastic range of the particle gel is between 10 and 50 Pa; the critical strain (ycritic) of the particle gel is about 0.01.
  • the particle gel has all of the following properties: the yield stress of the particle gel is from 1 to 10 Pa; the infinite viscosity of the particle gel determined using a fit of the stress s strain rate curve using a Casson model is less than 100 mPa.s; the viscosity of the particle gel at a shear rate of 20 s -1 is less than 420 mPa.s; the viscosity of the particle gel at a shear rate of 10 s -1 is less than 700 mPa.s; the elastic modulus G' determined on the linear viscoelastic range of the particle gel is between 10 and 50 Pa; and the critical strain (ycritic) of the particle gel is about 0.01.
  • the yield stress of the particle gel is from 1 to 10 Pa
  • the infinite viscosity of the particle gel determined using a fit of the stress s strain rate curve using a Casson model is less than 100 mPa.s
  • the viscosity of the particle gel at a shear rate of 20 s -1
  • the particles of the first clay are microparticles.
  • the particles of the first clay may have an average particle size of at least 1 pm.
  • the particles of the first clay have an average particle size of less than 1000 pm, for instance less than 500 pm, less than 250 pm or less than 100 pm.
  • the particles of the first clay may have a particle size of from 1 pm to 100 pm, typically from 1 pm to 50 pm, from 1 pm to 25 pm, preferably from 1 to 10 pm.
  • the particles of the first clay are in the form of platelets.
  • the particles of the first clay are platelets having an average particle size (maximum diameter i.e. the greatest edge to edge distance across the platelet) of at least 1 pm.
  • the particles of the first clay are platelets having an average particle size of less than 1000 pm, for instance less than 500 pm, less than 250 pm or less than 100 pm.
  • the particles of the first clay may be platelets having a particle size of from 1 pm to 100 pm, typically from 1 pm to 50 pm, from 1 pm to 25 pm, preferably from 1 to 10 pm.
  • the average particle size may be determined by microscopy, for instance by scanning electron microscopy (SEM) or transmission electron microscopy (TEM).
  • the first clay may be a water-swellable clay.
  • the first clay is a naturally occurring clay.
  • the first clay comprises a smectite, preferably a naturally occurring smectite, preferably montmorillonite.
  • the first clay comprises a sodium montmorillonite.
  • the first clay may be bentonite.
  • the first clay may be BentopharmTM, for instance BentopharmTM B20 grade. At the time of filing, BentopharmTM is commercially available from Wilfrid Smith Ltd.
  • the first clay does not comprise an organic modification.
  • the first clay is typically a purely inorganic material, without any organic groups incorporated into the bulk and/or grafted or adsorbed onto the surface.
  • the first clay may impart shear-thinning properties when mixed with a liquid phase in the absence of the second clay.
  • compositions comprising the first clay in the absence of the second clay form a very thick gel which is difficult for a consumer to handle after storage at elevated temperatures (for example, 40°C for 4 weeks).
  • the concentration of the first clay is not more than 25% by weight of the particle gel, not more than 20% by weight of the particle gel, not more than 15% by weight of the particle gel or not more than 10% by weight of the particle gel.
  • the concentration of the first clay may be at least 0.01% by weight of the particle gel, for instance at least 0.05% by weight of the particle gel, preferably at least 0.1% by weight of the particle gel.
  • the concentration of the first clay may be between 0.01 and 10% by weight of the particle gel, preferably between 0.1 and 5% by weight of the particle gel.
  • the concentration of the first clay may be about 0.5% by weight of the particle gel, about 1% by weight of the particle gel, about 1.5% by weight of the particle gel, about 2% by weight of the particle gel, about 2.5% by weight of the particle gel, about 3% by weight of the particle gel, about 3.5% by weight of the particle gel, about 4% by weight of the particle gel, about 4.5% by weight of the particle gel or about 5% by weight of the particle gel.
  • the concentration of the first clay is between 0.5 and 3% by weight of the particle gel.
  • the particles of the second clay are nanoparticles.
  • the particles of the second clay typically have an average particle size of less than 1 pm (1000 nm), usually from 0.1 nm to 1000 nm.
  • the particles of the second clay may have an average particle size of less than 750 nm, less than 500 nm, less than 250 nm, typically less than 100 nm or less than 50 nm.
  • the particles of the second clay may have an average particle size of at least 1 nm, at least 5 nm or at least 10 nm.
  • the particles of the second clay may have an average particle size of from 1 to 250 nm, or from 5 to 100 nm, preferably from 10 to 50 nm.
  • the particles of the second clay may have an average particle size of about 25 nm.
  • the particles of the second clay are in the form of platelets, typically nanoplatelets.
  • the particles of the second clay may be platelets having an average particle size (maximum diameter i.e the greatest edge to edge distance across the platelet) of less than 1 pm (1000 nm), usually from 0.1 nm to 1000 nm.
  • the particles of the second clay may be platelets having an average particle size of less than 750 nm, less than 500 nm, less than 250 nm, typically less than 100 nm or less than 50 nm.
  • the particles of the second clay may be platelets having an average particle size of at least 1 nm, at least 5 nm or at least 10 nm.
  • the particles of the second clay may be platelets having an average particle size of from 1 to 250 nm, or from 5 to 100 nm, preferably from 10 to 50 nm.
  • the particles of the second clay may be platelets having an average particle size of about 25 nm.
  • the second clay may impart shear-thinning properties when mixed with a liquid phase in the absence of the first clay. Indeed, in another aspect of the invention, certain formulations comprising the second clay only (i.e. without the first clay) are provided, as described herein.
  • the second clay comprises a clay material different to the first clay, an organic modification and optionally water, for instance water molecules trapped within the layers of the clay material.
  • the clay material in the second clay may be a water-swellable clay.
  • the second clay is a smectite with an organic modification, preferably a hectorite with an organic modification.
  • the clay material in the second clay may be a smectite, preferably a hectorite.
  • the second clay comprises a synthetic clay.
  • the clay material in the second clay may be a synthetic clay.
  • the second clay may be a synthetic hectorite with an organic modification.
  • the organic modification forms a part of the particles of the second clay.
  • the second clay typically comprises a clay material different to the first clay (preferably a hectorite, more preferably a synthetic hectorite), an organic modification and optionally water.
  • the organic modification may be a bulk modification or a surface modification. Alternatively, the organic modification may be present in both the bulk and on the surface of the clay material.
  • the organic modification is preferably a hydrophilic organic modification.
  • the second clay may be a synthetic hectorite clay with a hydrophilic organic modification.
  • Suitable hydrophilic organic modifications include organic compounds comprising carbonyl groups, for instance organic compounds comprising acetate groups.
  • the hydrophilic organic modifications may comprise an anionic polymer.
  • the hydrophilic organic modification may comprise a surfactant.
  • the hydrophilic organic modification may comprise an organic compound comprising a carboxylate anion, for instance a metal carboxylate.
  • the second clay comprises less than 95% by weight clay material, for instance less than 90% by weight clay material, less than 85% by weight clay material or less than 80% by weight clay material.
  • the second clay comprises at least 50% by weight clay material, at least 60% by weight clay material preferably at least 70% by weight clay material.
  • the second clay typically comprises from 50 to 95% by weight clay material, or from 60 to 85% by weight clay material, preferably from 70 to 80% clay material.
  • the second clay comprises less than 40% by weight of the organic modification, less than 30% by weight of the organic modification, preferably less than 20% by weight of the organic modification.
  • the second clay may comprise at least 1% by weight organic modification, at least 5% by weight organic modification or at least 10% by weight organic modification.
  • the second clay may comprise from 1 to 40% by weight organic modification, from 5 to 30% by weight organic modification preferably from 10 to 20% by weight organic modification.
  • the second clay comprises water.
  • the second clay may comprise from 1 to 30% by weight water, from 1 to 20% by weight water, preferably from 5 to 15% by weight water.
  • the second clay may comprise from 60 to 85% by weight clay material, from 5 to 30% by weight organic modification and from 1 to 20% by weight water.
  • the second clay comprises from 70 to 80% clay material, from 10 to 20% by weight organic modification and from 5 to 15% by weight water.
  • the content of clay material, organic modification and water may be determined using thermogravimetric-gas chromatography-mass spectrometry (TGA-GC-MS).
  • the percentages by weight of certain elements in the second clay may be determined using TGA-GC-MS and elemental analysis.
  • TGA-GC-MS and elemental analysis may show the presence of carbon indicating the presence of the organic modification.
  • the second clay comprises from 0.5% to 30% by weight carbon, for instance from 1 to 25% by weight carbon, from 5 to 20% by weight carbon, preferably from 5 to 15% by weight carbon.
  • the second clay comprises from 0.5% to 30% by weight carbon, from 1% to 10% by weight hydrogen, up to 5% by weight nitrogen, from 1% to 20% by weight magnesium, from 10% to 40% by weight silicon, from 0.01% to 1% by weight calcium, from 0.1% to 10% by weight sodium and from 0.01% to 1% by weight lithium.
  • the second clay may comprise from 5% to 15% by weight carbon, from 1% to 5% by weight hydrogen, from 0.1 to 2% by weight nitrogen, from 5% to 15% by weight magnesium, from 15% to 30% by weight silicon, from 0. 1% to 0.5% by weight calcium, from 0.5% to 5% by weight sodium and from 0.05% to 0.5% by weight lithium.
  • the second clay is LaponiteTM EP.
  • LaponiteTM EP is commercially available from BYK at https://www.byk.com/en/additives/additives-by- name/1 aponite-ep . php .
  • the concentration of the second clay is not more than 15% by weight of the particle gel, not more than 10% by weight of the particle gel, or not more than 5% by weight of the particle gel.
  • the concentration of the second clay may be at least 0.01% by weight of the particle gel, for instance at least 0.05% by weight of the particle gel.
  • the concentration of the second clay may be between 0.01 and 5 % by weight of the particle gel, preferably between 0.05 and 3% by weight of the particle gel.
  • the concentration of the second clay may be about 0.1% by weight of the particle gel, about 0.5% by weight of the particle gel, about 1% by weight of the particle gel, about 1.5% by weight of the particle gel, about 2% by weight of the particle gel, about 2.5% by weight of the particle gel, or about 3% by weight of the particle gel.
  • the concentration of the first clay is about 0.5% by weight of the particle gel.
  • the average particle size of the particles of the first clay is larger than that of the particles of the second clay.
  • the particles of the first clay may be microparticles and the particles of the second clay may be nanoparticles.
  • the average particle size of the particles of the first clay may be from 1 to 1000 pm and the average particle size of the particles of the second clay may be from 0.1 to 1000 nm.
  • the average particle size of the particles of the first clay may be from 1 to 100 pm and the average particle size of the particles of the second clay may be from 1 to 250 nm.
  • the average particle size of the particles of the first clay may be from 1 to 150 pm and the average particle size of the particles of the second clay may be from 5 to 100 nm.
  • the average particle size of the particles of the first clay may be from 1 to 10 pm and the average particle size of the particles of the second clay may be from 10 to 50 nm.
  • the particles of the first clay are platelets and the particles of the second clay are platelets.
  • the particles of the first clay may be microplatelets and the particles of the second clay may be nanoplatelets.
  • the average particle size (maximum diameter i.e. the greatest edge to edge distance across the platelet) of the platelets of the first clay may be from 1 to 1000 pm and the average particle size of the platelets of the second clay may be from 0.1 to 1000 nm.
  • the average particle size of the platelets of the first clay may be from 1 to 100 pm and the average particle size of the platelets of the second clay may be from 1 to 250 nm.
  • the average particle size of the platelets of the first clay may be from 1 to 50 pm and the average particle size of the platelets of the second clay may be from 5 to 100 nm.
  • the average particle size of the platelets of the first clay may be from 1 to 10 pm and the average particle size of the platelets of the second clay may be from 10 to 50 nm.
  • the first clay is a water-swellable clay and the second clay is a water-swellable clay.
  • both the first and second clays comprise a smectite.
  • the first clay may comprise a smectite and the second clay may comprise a smectite with an organic modification, preferably a hydrophilic organic modification.
  • the first clay is a naturally occurring clay whilst the second clay comprises a synthetic clay.
  • the first clay may be a naturally occurring smectite whilst the second clay may comprise a synthetic smectite with an organic modification, preferably a hydrophilic organic modification.
  • the first clay comprises montmorillonite, typically a sodium montmorillonite.
  • the first clay may be bentonite, e.g. BentopharmTM supplied by Wilfrid Smith Ltd, for instance BentopharmTM B20 grade.
  • the second clay comprises a synthetic hectorite with an organic modification, preferably a hydrophilic organic modification.
  • the first clay comprises montmorillonite and the second clay comprises a synthetic hectorite with an organic modification, preferably a hydrophilic organic modification.
  • the first clay may comprise sodium montmorillonite and the second clay comprises a synthetic hectorite with an organic modification, preferably a hydrophilic organic modification.
  • the first clay may be bentonite and the second clay may comprise a hectorite (typically a synthetic hectorite) with an organic modification, preferably a hydrophilic organic modification.
  • the second clay is LaponiteTM EP from BYK. Therefore, preferably the first clay is bentonite, typically BentopharmTM B20, and the second clay is LaponiteTM EP.
  • the first clay does not comprise an organic modification.
  • the first clay is typically a purely inorganic material, without any organic groups incorporated into the bulk and/or grafted or adsorbed onto the surface.
  • the second clay comprises an organic modification as described herein, typically a hydrophilic organic modification as described herein.
  • the concentration of the first clay is between 0.01 and 10% by weight of the particle gel and the concentration of the second clay may be between 0.01 and 5 % by weight of the particle gel.
  • the concentration of the first clay is between 0.1 and 5% by weight of the particle gel and the concentration of the second clay is between 0.05 and 3% by weight of the particle gel.
  • the liquid phase comprises water.
  • the liquid phase is typically aqueous.
  • Further ingredients, such as surfactants, salts, anti-freeze agents and dispersants may be dissolved in the liquid phase.
  • the particle gel of the invention may comprise particles of a first clay, having an average particle size of 1 to 100 pm, said particles of the first clay preferably being platelets, wherein the first clay is a naturally occurring clay; particles of a second clay having an average particle size of from 1 to 250 nm, said particles of the second clay preferably being platelets, wherein the second clay is a synthetic clay comprising a hydrophilic organic modification; and a liquid phase comprising water.
  • the particle gel of the invention may comprise particles of a first clay, having an average particle size of 1 to 50 pm, said particles of the first clay preferably being platelets, wherein the first clay comprises a naturally occurring smectite, preferably wherein the first clay is bentonite; particles of a second clay having an average particle size of from 5 to 100 nm, said particles of the second clay preferably being platelets, wherein the second clay is a synthetic hectorite clay comprising a hydrophilic organic modification, preferably LaponiteTM EP; and a liquid phase comprising water.
  • the particle gel of the invention may comprise particles of a first clay, having an average particle size of 1 to 10 pm, said particles of the first clay preferably being platelets, wherein the first clay comprises a naturally occurring smectite, preferably wherein the first clay is bentonite; particles of a second clay having an average particle size of from 10 to 50 nm, said particles of the second clay preferably being platelets, wherein the second clay is a synthetic hectorite clay comprising a hydrophilic organic modification, preferably LaponiteTM EP; and a liquid phase comprising water.
  • the particle gel of the invention comprises one or more active ingredients.
  • the particle gel of the invention may comprise at least two active ingredients, at least three active ingredients or at least four active ingredients
  • the active ingredient(s) may be any ingredient which imparts a particular utility or property to the particle gel.
  • the active ingredient may be an agrochemical, a pigment, a pharmaceutical or a cosmetic ingredient.
  • at least one of the active ingredients is dispersed in the particle gel or is present in the particle gel in emulsified form. In other words, at least one of the active ingredients is only partially soluble or is insoluble in the liquid phase and hence dispersible. Thus, typically, at least one of the active ingredients is only partially soluble in water, or is insoluble in water.
  • active ingredients examples include thiamethoxam, atrazine, azoxystrobin and mesotrione.
  • the active ingredient is typically dissolved in an oil, for instance an alkylnaphthalene oil such as the solvent SolvessoTM 200.
  • examples of such active ingredients which may be present in emulsified form include S-metolachlor, prosulfocarb, trinexapac-ethyl, clomazone, tefluthrin and lambda-cyhalothrin.
  • the particle gel further comprises one or more surfactants, typically anionic or non-ionic surfactants, as described herein.
  • the particle gel may further comprise other ingredients such as one or more anti-foaming agents, for instance Dow Corning TM antifoam MSA or Dow Coming TM antifoam 1520.
  • At least one of the active ingredients may be an agrochemical. Where there are more than one active ingredients present either all or some of the active ingredients may be agrochemicals.
  • the particle gel may comprise at least two active ingredients which are agrochemicals, at least three active ingredients which are agrochemicals or at least four active ingredients which are agrochemicals. Typically, at least one of those active ingredients (agrochemicals) is dispersed in the particle gel or is present in the particle gel in emulsified form. In other words, at least one of the active ingredients (agrochemicals) is not soluble in the aqueous liquid phase.
  • the agrochemical may be selected from a pesticide, a fungicide, an insecticide or an herbicide, or a plant growth regulator.
  • the agrochemical may be a fungicide which is azoxystrobin, an herbicide which is mesotrione or an insecticide which is thiamethoxam.
  • the concentration of the active ingredient which is not soluble in the liquid phase is from 0.1 to 60 % by weight of the particle gel, for instance from 10 to 40% by weight of the particle gel or from 5 to 20% by weight of the particle gel.
  • the particle gel of the present invention may further comprise a salt.
  • the salt is a salt of an active ingredient.
  • at least one active ingredient may be a salt, typically a salt which is soluble in the liquid phase of the particle gel.
  • the salt is a water- soluble salt.
  • the particle gel comprises at least one active ingredient which is dispersed in the particle gel or is present in the particle gel in emulsified form and at least one active ingredient which is a salt, preferably a salt which is soluble in the liquid phase of the particle gel.
  • the particle gel may comprise only active ingredients which are dispersed in the particle gel or is present in the particle gel in emulsified form (i.e. which are insoluble in the liquid phase) or the particle gel may comprise only active ingredients which are salts which are soluble in the liquid phase of the particle gel.
  • At least one of the active ingredients may be a salt of an agrochemical, for example a pesticide, herbicide or fungicide salt.
  • the particle gel may therefore comprise at least one active ingredient which is an agrochemical (for instance a pesticide, insecticide, herbicide or fungicide) which is dispersed in the particle gel or is present in the particle gel in emulsified form and at least one active ingredient which is a salt of an agrochemical (for instance a pesticide, insecticide, herbicide or fungicide salt, or the salt of a plant growth regulator) which is soluble in the liquid phase.
  • an agrochemical for instance a pesticide, insecticide, herbicide or fungicide
  • a salt of an agrochemical for instance a pesticide, insecticide, herbicide or fungicide salt, or the salt of a plant growth regulator
  • agrochemicals which are soluble in the liquid phase include glyphosate as the potassium salt, dicamba as the sodium salt, 2,4-D as the dimethylamine salt and glufosinate as the ammonium salt.
  • the agrochemical may be a salt of a plant growth regulator, for instance a plant growth regulator which is a mepiquat halide, typically mepiquat chloride. Plant growth regulators may enhance or suppress plant growth, or direct plant growth in a particularly desired way (e.g. to increase yield of a particular product).
  • the salt may be an inorganic salt, for instance an alkaline or alkali earth metal salt.
  • the salt is not an active ingredient, but is present to modify the ionic strength of the particle gel.
  • the particle gel may comprise more than one salt, for instance one salt which is a salt of an active ingredient and another salt which is an inorganic salt, for instance an alkaline or alkali earth metal salt.
  • such salts include lithium halides, sodium halides, potassium halides, magnesium halides and calcium halides.
  • the salt may be magnesium chloride (MgCl 2 ) or sodium chloride (NaCl).
  • the concentration of the salt is from 0.1 to 60% by weight of the particle gel, for instance from 0.1 to 40 % by weight of the particle gel, preferably from 5 to 30% by weight of the particle gel.
  • the particle gel of the present invention may further comprise a dispersant.
  • the dispersant is a non-ionic or anionic dispersant.
  • the person skilled in the art would be well aware of suitable dispersants and would be able to select a dispersant based on the particular characteristics of the particle gel. Dispersants are typically added to improve the separation of particles and to prevent settling or clumping.
  • the particle gel may comprise a dispersant which is an anionic dispersant.
  • anionic dispersants include salts of alkylnaphthalenesulphates (for instance the polymeric material MorwetTM D425 from Nouryon).
  • the particle gel may comprise a dispersant which is a non-ionic dispersant.
  • Non-ionic dispersants include hydrophilic polymers, typically hydrophilic comb-like polymers, for instance hydrophilic methyl methacrylate graft copolymers (for instance AtloxTM 4913 from Croda).
  • the concentration of the dispersant is from 0.1 to 20 % by weight of the particle gel, preferably from 1% to 10% by weight of the particle gel or from 1 to 5% by weight of the particle gel.
  • the particle gel may comprise a surfactant.
  • a surfactant typically added to improve the stability of an emulsion, by lowering the surface tension between the liquid phase (typically aqueous) and the droplets of the emulsion (typically an oil). Surfactants may be added to improve the bio-efficacy of a leaf-applied agrochemical product.
  • the surfactant is a non-ionic surfactant, for instance polyethylene glycol sorbitan monolaurate (such as Tween® 20), tri-styryl-phenol-ethoxylates (such as SoprophorTM BSU) and alkyl ethoxylates (such as SynperonicTMAl 1 and SynperonicTMNP13).
  • the concentration of the surfactant is from 0.1 to 50% by weight of the particle gel, typically from 0.1 to 20 % by weight of the particle gel. pH
  • the particle gel may further comprise a pH-modifying agent.
  • the pH of the particle gel is between 2 and 10.
  • the particle gel comprises a pH- modifying agent that imparts a pH of between 2 and 10 to the particle gel.
  • the pH-modifying agent may be an acid.
  • the pH of the particle gel may be between 2 and 7, preferably between 3 and 5.
  • the pH-modifying agent may be an acid selected from an inorganic acid such as hydrohalic acid, sulfuric acid, sulfonic acid, nitric acid, phosphoric acid, phosphonic acid, or an organic acid such as a carboxylic acid.
  • the acid is hydrochloric acid (HC1) or acetic acid (CH 3 COOH).
  • the pH-modifying agent may be an alkali.
  • the pH of the particle gel may be between 7 and 10.
  • the pH-modifying agent may be an alkali selected from an inorganic alkali such as an alkali or alkaline earth hydroxide or an alkali or alkaline earth carbonate, or an organic base such as an amine.
  • the amount of acid or base in the particle gel may be any amount suitable to achieve the desired pH.
  • the skilled person would readily be able to add an appropriate amount of acid or base and test the pH for instance using a pH probe or indicator paper.
  • the particle gel according may comprise an anti-freezing agent.
  • suitable anti-freezing agent are chemicals that reduce the freezing temperature of the particle gel, relative to an equivalent particle gel without the anti-freezing agent present.
  • the anti-freezing agent is propylene glycol. Salts such as sodium chloride may also be used as anti-freezing agents.
  • the concentration of the anti-freezing agent is from 5 to 25% by weight of the particle gel, preferably from 10 to 20% by weight of the particle gel.
  • the particle gel may comprise two or more, for instance three or more or four or more selected from the group consisting of a surfactant as described herein, a dispersant as described herein, a salt as described herein, a pH modifying agent as described herein and an anti-freezing agent as described herein.
  • the particle gel may comprise a surfactant as described herein, a dispersant as described herein, a salt as described herein, a pH modifying agent as described herein and an anti-freezing agent as described herein.
  • the invention also provides a process for producing a composition for use in agriculture, which process comprises diluting a particle gel as described herein with water.
  • the invention also provides a composition for use in agriculture, wherein the composition is obtainable by diluting a particle gel as described herein with water.
  • the particle gel composition as described herein is diluted by a factor of between 1 in 10 and 1 in 1000, typically 1 part in 100 of water.
  • the particle gel composition as described herein may be diluted by a factor of between 1 part in 10 and 1 part in 200, typically from 1 part in 25 to 1 part in 150, preferably from 1 part in 50 to 1 part in 100.
  • the composition is diluted to enable efficient spraying across fields.
  • the invention also provides a composition comprising a bentonite clay and a hectorite clay, wherein the hectorite clay comprises an organic modification.
  • the organic modification may be any organic modification as described herein.
  • the organic modification is a hydrophilic organic modification.
  • the hectorite clay is a synthetic hectorite clay.
  • the composition comprises a bentonite clay and a synthetic hectorite clay, wherein the synthetic hectorite clay comprises a hydrophilic organic modification.
  • the organic modification may be a bulk modification or a surface modification. Alternatively the organic modification may be present in both the bulk and on the surface of the clay material.
  • Suitable hydrophilic organic modifications include organic compounds comprising carbonyl groups, for instance organic compounds comprising acetate groups.
  • the hydrophilic organic modifications may comprise an anionic polymer.
  • the hydrophilic organic modification may comprise a surfactant.
  • the hydrophilic organic modification may comprise an organic compound comprising a carboxylate anion, for instance a metal carboxylate.
  • the hectorite clay comprises less than 95% by weight clay material, for instance less than 90% by weight clay material, less than 85% by weight clay material or less than 80% by weight clay material.
  • the hectorite clay comprises at least 50% by weight clay material, at least 60% by weight clay material preferably at least 70% by weight clay material.
  • the hectorite clay typically comprises from 50 to 95% by weight clay material, or from 60 to 85% by weight clay material, preferably from 70 to 80% clay material.
  • the hectorite clay comprises less than 40% by weight of the organic modification, less than 30% by weight of the organic modification, preferably less than 20% by weight of the organic modification.
  • the hectorite clay may comprise at least 1% by weight organic modification, at least 5% by weight organic modification or at least 10% by weight organic modification.
  • the hectorite clay may comprise from 1 to 40% by weight organic modification, from 5 to 30% by weight organic modification, preferably from 10 to 20% by weight organic modification.
  • the hectorite clay comprises water.
  • the hectorite clay may comprise from 1 to 30% by weight water, from 1 to 20% by weight water, preferably from 5 to 15% by weight water.
  • the hectorite clay may comprise from 60 to 85% by weight clay material, from 5 to 30% by weight organic modification and from 1 to 20% by weight water.
  • the hectorite clay comprises from 70 to 80% clay material, from 10 to 20% by weight organic modification and from 5 to 15% by weight water.
  • the content of clay material, organic modification and water may be determined using thermogravimetric-gas chromatography-mass spectrometry (TGA-GC-MS).
  • the percentages by weight may be determined using TGA-GC-MS and elemental analysis.
  • TGA-GC-MS and elemental analysis may show the presence of carbon indicating the presence of the organic modification.
  • the hectorite clay comprises from 0.5% to 30% by weight carbon, for instance from 1 to 25% by weight carbon, from 5 to 20% by weight carbon, preferably from 5 to 15% by weight carbon.
  • the hectorite clay comprises from 0.5% to 30% by weight carbon, from 1% to 10% by weight hydrogen, up to 5% by weight nitrogen, from 1% to 20% by weight magnesium, from 10% to 40% by weight silicon, from 0.01% to 1% by weight calcium, from 0.1% to 10% by weight sodium and from 0.01% to 1% by weight lithium.
  • the hectorite clay may comprise from 5% to 15% by weight carbon, from 1% to 5% by weight hydrogen, from 0.1 to 2% by weight nitrogen, from 5% to 15% by weight magnesium, from 15% to 30% by weight silicon, from 0. 1% to 0.5% by weight calcium, from 0.5% to 5% by weight sodium and from 0.05% to 0.5% by weight lithium.
  • the hectorite clay is Laponite TM EP from BYK.
  • the composition preferably comprises a bentonite clay and Laponite TM EP.
  • the bentonite clay may be BentopharmTM supplied by Wilfrid Smith Ltd, for instance BentopharmTM B20 grade.
  • composition may comprise BentopharmTM and Laponite TM EP.
  • the invention also provides an agrochemical formulation comprising
  • the hectorite clay comprising an organic modification is the only thickening agent present in the agrochemical formulation.
  • the hectorite clay comprising an organic modification is the only thickening agent present in the agrochemical formulation.
  • only one clay is present in the agrochemical formulation (namely the hectorite clay comprising an organic modification).
  • the agrochemical formulation is a non-Newtonian fluid.
  • the viscosity of the agrochemical formulation usually decreases upon application of a force.
  • the agrochemical formulation is a shear-thinning fluid.
  • the agrochemical formulation may be thixotropic. Thixotropic materials display time-dependent shear thinning behaviour. For instance, thixotropic materials take a finite time to attain equilibrium viscosity when introduced to a change in shear rate.
  • the hectorite clay may be any hectorite clay as described herein.
  • the hectorite clay is a synthetic hectorite clay.
  • the composition comprises a synthetic hectorite clay comprising a hydrophilic organic modification.
  • the organic modification may be a bulk modification or a surface modification. Alternatively the organic modification may be present in both the bulk and on the surface of the clay material.
  • Suitable hydrophilic organic modifications include organic compounds comprising carbonyl groups, for instance organic compounds comprising acetate groups.
  • the hydrophilic organic modifications may comprise an anionic polymer.
  • the hydrophilic organic modification may comprise a surfactant.
  • the hydrophilic organic modification may comprise an organic compound comprising a carboxylate anion, for instance a metal carboxylate.
  • the hectorite clay comprises less than 95% by weight clay material, for instance less than 90% by weight clay material, less than 85% by weight clay material or less than 80% by weight clay material.
  • the hectorite clay comprises at least 50% by weight clay material, at least 60% by weight clay material preferably at least 70% by weight clay material.
  • the hectorite clay typically comprises from 50 to 95% by weight clay material, or from 60 to 85% by weight clay material, preferably from 70 to 80% clay material.
  • the hectorite clay comprises less than 40% by weight of the organic modification, less than 30% by weight of the organic modification, preferably less than 20% by weight of the organic modification.
  • the hectorite clay may comprise at least 1% by weight organic modification, at least 5% by weight organic modification or at least 10% by weight organic modification.
  • the hectorite clay may comprise from 1 to 40% by weight organic modification, from 5 to 30% by weight organic modification, preferably from 10 to 20% by weight organic modification.
  • the hectorite clay comprises water.
  • the hectorite clay may comprise from 1 to 30% by weight water, from 1 to 20% by weight water, preferably from 5 to 15% by weight water.
  • the hectorite clay may comprise from 60 to 85% by weight clay material, from 5 to 30% by weight organic modification and from 1 to 20% by weight water.
  • the hectorite clay comprises from 70 to 80% clay material, from 10 to 20% by weight organic modification and from 5 to 15% by weight water.
  • the content of clay material, organic modification and water may be determined using thermogravimetric-gas chromatography-mass spectrometry (TGA-GC-MS).
  • the percentages by weight may be determined using TGA-GC-MS and elemental analysis.
  • TGA-GC-MS and elemental analysis may show the presence of carbon indicating the presence of the organic modification.
  • the hectorite clay comprises from 0.5% to 30% by weight carbon, for instance from 1 to 25% by weight carbon, from 5 to 20% by weight carbon, preferably from 5 to 15% by weight carbon.
  • the hectorite clay comprises from 0.5% to 30% by weight carbon, from 1% to 10% by weight hydrogen, up to 5% by weight nitrogen, from 1% to 20% by weight magnesium, from 10% to 40% by weight silicon, from 0.01% to 1% by weight calcium, from 0.1% to 10% by weight sodium and from 0.01% to 1% by weight lithium.
  • the hectorite clay may comprise from 5% to 15% by weight carbon, from 1% to 5% by weight hydrogen, from 0.1 to 2% by weight nitrogen, from 5% to 15% by weight magnesium, from 15% to 30% by weight silicon, from 0.
  • the hectorite clay is LaponiteTM EP from BYK.
  • the agrochemical formulation preferably comprises LaponiteTM EP.
  • the hectorite clay is present in an amount of from 0.01 to 5% by weight of the agrochemical formulation.
  • the hectorite clay may be present in an amount of from 0.05% to 2% by weight of the agrochemical formulation, preferably between 0.2% to 1.5% by weight of the agrochemical formulation.
  • the agrochemical formulation comprises a liquid phase.
  • the liquid phase typically comprises water.
  • the liquid phase is typically aqueous.
  • Further ingredients, such as surfactants, salts, anti-freeze agents and dispersants may be dissolved in the liquid phase.
  • At least one of the active ingredients in the agrochemical formulation is a salt of an agrochemical.
  • the hectorite clay comprising an organic modification is able to impart the desired rheological properties in terms of gel formulation and shear-thinning.
  • the agrochemical formulation of the present invention is particularly well-suited for formulations comprising soluble salts of agrochemicals, for instance, herbicide, pesticide or fungicide salts or the salt of a plant growth regulator.
  • salts examples include glyphosate as the potassium salt, dicamba as the sodium salt, 2,4-D as the dimethylamine salt, glufosinate as the ammonium salt and halide salts of mepiquat.
  • the agrochemical may be a salt of a plant growth regulator, for instance a plant growth regulator which is a mepiquat halide, typically mepiquat chloride.
  • the agrochemical formulation may comprise multiple active ingredients which are salts of agrochemicals.
  • the agrochemical formulation may comprise at least two active ingredients which are salts of agrochemicals, at least three active ingredients which are salts of agrochemicals or at least four active ingredients which are salts of agrochemicals.
  • the salts of agrochemicals may be selected from herbicide, pesticide or fungicide salts and/or salts of a plant growth regulator.
  • the salts of agrochemicals may be selected from glyphosate as the potassium salt, dicamba as the sodium salt, 2,4-D as the dimethylamine salt, glufosinate as the ammonium salt and halide salts of mepiquat.
  • the agrochemical may be a salt of a plant growth regulator, for instance a plant growth regulator which is a mepiquat halide, typically mepiquat chloride.
  • a plant growth regulator which is a mepiquat halide, typically mepiquat chloride.
  • Other salts include salts of dicamba and salts of glyphosate.
  • the agrochemical formulation comprises a synthetic hectorite clay which comprises a hydrophilic organic modification and at least one salt of an agrochemical selected from herbicide, pesticide or fungicide salts and/or salts of a plant growth regulator.
  • the agrochemical formulation may comprise LaponiteTM EP and at least one salt of an agrochemical selected from herbicide, pesticide or fungicide salts and/or salts of a plant growth regulator.
  • the agrochemical formulation may comprise LaponiteTM EP and at least a mepiquat halide, typically mepiquat chloride.
  • the agrochemical formulation may comprise LaponiteTM EP and the salt of an herbicide, for instance a dicamba salt or a glyphosate salt.
  • the agrochemical is present in the agrochemical formulation in an amount from 10 to 70% by weight, for instance from 20 to 60 % by weight, preferably from 30 to 50% by weight.
  • the agrochemical formulation may further comprise one or more agrochemicals which are dispersed in the agrochemical formulation or are present in the agrochemical formulation in emulsified form.
  • at least one of the agrochemicals may be only partially water soluble or insoluble in water.
  • the agrochemical is typically emulsified in an oil, for instance an alkylnaphthalene solvent such as SolvessoTM 200.
  • the agrochemical formulation further comprises one or more surfactants, typically anionic or non-ionic surfactants, as described herein.
  • the particle gel may further comprise one or more anti-foaming agents. Suitable anti-foaming agents include Dow Corning TM antifoam MSA and Dow Coming TM antifoam 1520.
  • the agrochemical formulation may further comprise one or more agrochemicals which are dispersed in the agrochemical formulation or are present in the agrochemical formulation in emulsified form selected from pesticides, fungicides, insecticides, herbicides and plant growth regulators.
  • the agrochemical formulation may comprise a fungicide which is azoxystrobin.
  • the agrochemical formulation may comprise a surfactant as described herein.
  • the agrochemical formulation may comprise a dispersant as described herein.
  • the agrochemical formulation may comprise a salt as described herein.
  • the agrochemical formulation may comprise a pH modifying agent as described herein.
  • the agrochemical formulation may comprise an anti-freezing agent as described herein.
  • the agrochemical formulation may comprise two or more, for instance three or more or four or more selected from the group consisting of a surfactant as described herein, a dispersant as described herein, a salt as described herein, a pH modifying agent as described herein and an anti-freezing agent as described herein.
  • the agrochemical formulation may comprise a surfactant as described herein, a dispersant as described herein, a salt as described herein, a pH modifying agent as described herein and an anti freezing agent as described herein.
  • the invention also provides the use of a particle gel as described herein, a composition as described herein, or an agrochemical formulation as described herein, as a plant protection product.
  • a plant protection product maybe any product designed to protect plants of interests from pests (e g. insects, fungal diseases) or from competition for resources from other plants.
  • the plant protection product typically comprises at least one active ingredient that protects plants.
  • the plant protection product comprises at least one of a fungicide as described herein, an insecticide as described herein, an herbicide as described herein or a plant growth regulator as described herein.
  • the particle gel as described herein, composition as described herein, or agrochemical formulation as described herein may be used as a fungicide.
  • the particle gel as described herein, composition as described herein, or agrochemical formulation as described herein may be used as an insecticide.
  • the particle gel as described herein, composition as described herein, or agrochemical formulation as described herein may be used as an herbicide.
  • the particle gel as described herein, composition as described herein, or agrochemical formulation as described herein may be used to regulate plant growth.
  • the particle gel as described herein, composition as described herein, or agrochemical formulation as described herein is typically used to protect a crop of interest, for instance on a farm.
  • the particle gel as described herein, composition as described herein, or agrochemical formulation as described herein may be used to protect a maize crop or a cereal crop.
  • Example 1 Formulations of azoxystrobin as Suspension Concentrate (SC) #1 comprising anionic dispersant in the millbase
  • LaponiteTM EP 2% gel was prepared as followed: 2g of LaponiteTM EP put into 50g of water then addition of water up to lOOg. Then high shear applied with a high shear mixer from IKA (ULTRA-TURRAXTM digital T25 with impeller S25N-18G) at about 17,000 rpm for about 10 minutes until dissolution. Then centrifugation at 1000 rpm for 5mins was used to remove air bubbles. BentopharmTM B20 10% gel was prepared as follows: 90g of water to which lOg of
  • Example 1 ingredients were then mixed in the following order according to the following recipes:
  • Millbase #1 (comprising an anionic dispersant, 6% by mass MorwetTM D425, and an active ingredient, the fungicide Azoxystrobin at 50% by mass dispersed in water)
  • Rheological test protocol Frequency oscillations test Conditioning at 25°C ; pre-shear at 100 s -1 for 60s; equilibration for 1200s Frequency Oscillation at 25°C; from 10 2 to 100 Hz; at 1 Pa or O.lPa (Control with anionic dispersant) or at a stress within the LVR; conditioning cycles: 15; sampling cycles: 10 Results initial rheological tests (flow ramp and oscillation tests)
  • Figure 4 shows the frequency oscillation results for the first samples only. All samples showed the same behaviour with time showing that the gels were stable for a long time.
  • Model established using the mode-coupling theory (MCT) see Lidon, Pierre, Louis Villa, and Sebastien Manneville. "Power-law creep and residual stresses in a carbopol gel.” Rheologica Acta 56.3 (2017): 307-323):
  • the pourability test was performed as follows: a 25mL cylinder was weighed empty (W 1), - the gel was poured into the cylinder and the weight was recorded (W2)
  • the cylinder was emptied back into the original sample bottle by tilting the cylinder at 45° for 60s and holding it vertically for 60s afterwards.
  • Table 5 Storage test results of rheological tests after four weeks storage at 40°C The same rheological tests as described above were performed on the samples after four weeks storage in non-ideal conditions (at 40°C).
  • Table 6 and Figure 5 show the flow ramp results.
  • Table 7 and Figure 6 show the viscoelasticity results.
  • Table 7 Storage test results of industrial tests after four weeks storage at 40°C No phase separation was observed for either sample after four weeks storage at 40°C.
  • the pourability and dilution tests results, assessed according the method described above, are provided below in Table 8.
  • Example 2 Formulation of azoxystrobin Suspension Concentrate (SC) #2 using nonionic dispersant in the millbase
  • Millbase comprising a non-ionic dispersant, 6% by mass AtloxTM 4913, and an active ingredient, a fungicide Azoxystrobin at 50% by mass dispersed in water
  • Millbase comprising a non-ionic dispersant, 6% by mass AtloxTM 4913, and an active ingredient, a fungicide Azoxystrobin at 50% by mass dispersed in water
  • Table 10 Strain oscillation results are shown in Figure 9.
  • Table 11 shows the results for the elastic modulus (G’), the loss modulus (G”) and the critical strain (“/critic).
  • Figure 10 shows the frequency oscillation results for the first samples only. All samples showed the same behaviour with time showing that the gels were stable for a long time. Model established using the mode-coupling theory (MCT) as described above. Results for the fitting of G” are shown in Table 12.
  • Example 3 comparison between LaponiteTM EP (with organic modification) 2% w/w and LaponiteTM RD (without organic modification) 5% w/w
  • LaponiteTM EP 2% gel was prepared as described above.
  • LaponiteTM RD 5% gel was prepared as followed: 5g of LaponiteTM RD put into 50g of water then addition of water up to lOOg. Then high shear with a high shear mixer from IKA (ULTRA-TURRAXTM digital T25 with impeller S25N-18G) for about 10 minutes until dissolution. Then centrifugation to remove air bubble at 1000 rpm for 5 minutes.
  • IKA ULTRA-TURRAXTM digital T25 with impeller S25N-18G
  • Rheological protocol for evaluating aging of the gel (using a DIN rotor geometry (geometry fitted to the rheometer) or a Vane rotor): Conditioning at 25°C; pre-shear at 100 s -1 for 60s First time Oscillation at 25°C; during 440000s (5 days) or stopped before; at lHz; at 1 Pa or within the LVR; conditioning cycles: 20; sampling cycles: 10 Conditioning at 25°C; pre-shear at 100 s -1 for 60s Second time Oscillation at 25°C; during 440000s (5days) or stopped before; at 1Hz; at a 1 Pa or within the LVR; conditioning cycles: 20; sampling cycles: 10
  • the gelation concentration is not the same: 2% of LaponiteTM EP is enough to have a strong gel whereas it is not with LaponiteTM RD.
  • Examples 4-6 comparison between LaponiteTM EP - BentopharmTM and LaponiteTM RD -BentopharmTM - effect of pH, salt (MgCh) and surfactant (TWEEN20)
  • Rheological protocol (using a DIN rotor geometry (geometry fitted to the rheometer) or a Vane rotor (for the first 3 parts)): Conditioning at 25°C; pre-shear at 100 s -1 for 60s; equilibration for 1200s Time Oscillation at 25°C; during lh30 or 3 hours; at lHz; at a fixed stress (within the LVR); conditioning cycles: 20; sampling cycles: 10 Strain Oscillation at 25°C; from 10 4 to 10; at 1 Hz; conditioning cycles: 10; sampling cycles: 10 Conditioning at 25°C; pre-shear at 600 s 1 for 60s; equilibration for 600s; Ramp up at 25°C; from 0 to 600 s 1 for 900s; sampling interval: 1 s/pt Ramp down at 25°C; from 600 to 0 s 1 for 900s; sampling interval: 1 s/pt Flow properties: fitting of the flow ramp up with Casson model
  • Example 4 comparison between LaponiteTM EP - BentopharmTM and LaponiteTM RD -BentopharmTM - effect of pH
  • Figure 17 and Table 19 show the results of the flow ramp testing on LaponiteTM RD 15g/L + BentopharmTM 20g/L (without pH modification) compared to LaponiteTM RD 15g/L +
  • Example 5 comparison between LaponiteTM EP - BentopharmTM and LaponiteTM RD -BentopharmTM - effect of a salt (MgCh)
  • Figure 19 shows the results of the flow ramp testing for LaponiteTM EP 5g/L + BentopharmTM 20g/L with various concentrations of MgCh.
  • the gel is strengthened with MgCh, possibly because MgCh is very hygroscopic and its addition decreases the osmotic pressure in the bulk with water leaving the network to go to the bulk -> contraction of the electrical double layer.
  • MgCh is very hygroscopic and its addition decreases the osmotic pressure in the bulk with water leaving the network to go to the bulk -> contraction of the electrical double layer.
  • the platelets get closer to each other which increases the strength of the network Results w ith LaponiteTM RD
  • Figure 21 shows the results of the flow ramp testing for LaponiteTM RD 15g/L + BentopharmTM 20g/L with various concentrations of MgCh.
  • the gel is also strengthened with MgCh, the same hypothesis described in the case of LaponiteTM EP 5g/L + BentopharmTM 20g/L can be applied for LaponiteTM RD 15g/L + BentopharmTM 20g/L.
  • Example 6 comparison between LaponiteTM EP - BentopharmTM and LaponiteTM RD -BentopharmTM - effect of a surfactant (Tween 20)
  • Figure 23 and Table 23 show the results of the flow ramp testing LaponiteTM EP 5g/L + BentopharmTM 20g/L (without surfactant) and for LaponiteTM EP 5g/L + BentopharmTM 20g/L (with various concentrations of surfactant - Tween 20).
  • the gel comprising LaponiteTM EP is strengthened with Tween 20.
  • An increase in yield stress and viscosity is observed with increasing concentration of Tween 20.
  • the results obtained with 20% (w/w) may be due to the formation of micelles or a highly ordered system in the bulk increasing the viscosity of the solution whereas the critical micelle concentration may not have been reached at a concentration of 1 or 10%.
  • Tween 20 does not destroy the gel structure, whereas it does for LaponiteTM RD (see results below).
  • Figure 25 and Table 25 show the results of the flow ramp testing for LaponiteTM RD 15g/L + BentopharmTM 20g/L (without surfactant) and for LaponiteTM RD 15g/L + BentopharmTM 20g/L (with various concentrations of surfactant - Tween 20).
  • the gel comprising LaponiteTM RD is weakened when Tween 20 is added.
  • Example 7 comparison of different azoxystrobin SC using LaponiteTM EP as gelling agent with the anionic dispersant containing millbase
  • Millbase #1 (comprising an anionic dispersant, 6% by mass MorwetTM D425, and an active ingredient, a fungicide Azoxystrobin at 50% by mass dispersed in water)
  • the mix of water, Millbase #1 and propylene glycol is referred to as anionic suspension in this example and in Figure 26 and Figure 27.
  • Figure 27 and Table 27 show the results of the flow ramp testing for LaponiteTM EP 5g/L, LaponiteTM EP lOg/L or LaponiteTM EP 5g/L + BentopharmTM 20g/L.
  • Example 8 effect of LaponiteTM EP and LaponiteTM RD upon the gelling of a range of electrolyte solutions including agrochemicals
  • LaponiteTM EP pre-gels were combined with a range of electrolyte (salt) solutions by mixing.
  • the following salt solutions were investigated:
  • LaponiteTM EP and LaponiteTM RD as 2% by mass aqueous gels were both prepared as explained in Examples 1 and 2.
  • a LaponiteTM EP gel was also made at 4.5% by mass for Sample 3 specifically.
  • Mepiquat chloride technical powder material (98.3% chemical purity) was weighed into a glass jar and then LaponiteTM gel added followed by mild agitation by rolling within the glass jar for 1 hour.
  • bentonite clay (BentopharmTM B20) was not readily dispersible in the Mepiquat chloride salt solution. There was apparently an unfavourable interaction that appeared to render the bentonite clay as hydrophobic.
  • Example 9 comparison of different SC containing Azoxystrobin with anionic dispersant using Laponite TM EP as gelling agent. Preparation of the Solution Concentrates
  • Millbase #1 as supplied by Syngenta Limited comprising an anionic dispersant, 6% by mass MorwetTM D425, and an active ingredient, a fungicide Azoxystrobin at 50% by mass dispersed in water 3.
  • the mix of water, Millbase #1 and propylene glycol is referred to as anionic suspension in this example and in Figure 28 and Figure 29.
  • Figure 29 and Table 33 show the results of the flow ramp test for LaponiteTM EP 5g/L, LaponiteTM EP lOg/L, Bentopharm 20g/L, Bentopharm 40g/L and LaponiteTM EP 5g/L + BentopharmTM 20g/L. Note that the values displayed in Table 33 for LaponiteTM EP 5g/L, LaponiteTM EP lOg/L and LaponiteTM EP 5g/L + BentopharmTM 20g/L were obtained based on the mean of two repetitions.
  • Example 10 study of the combination of LaponiteTM EP + Ben top harm with mesotrione acid as active ingredient (formulated as copper chelate)
  • LaponiteTM EP 2% gel was prepared as previously described.
  • RhodopolTM 2% gel was prepared as follows: 2g of RhodopolTM added to 50g of water then addition of water to lOOg. Then high shear mixing using an IKA high shear mixer (ULTRA- TURRAXTM digital T25 with impeller S25N-18G) at 19200 rpm for 6 minutes and 21 000 rpm for 5 minutes afterwards. Then centrifugation at 1000 rpm for 5 minutes to remove air bubbles. The foam formed at the top was removed with a spatula.
  • IKA high shear mixer ULTRA- TURRAXTM digital T25 with impeller S25N-18G
  • AttagelTM 10% gel was prepared as follows: lOg of AttagelTMwere added to 50g of water then addition of water to lOOg. Then high shear mixing using an IKA high shear mixer
  • Figure 30 shows the stress versus strain rate curve and the viscosity versus strain rate for LaponiteTM EP combined with BentopharmTM as thickening agent against the control with RhodopolTM (xanthan) only, for gel containing copper-mesotrione.
  • Figure 31 shows stress versus strain rate curve and the viscosity versus strain rate for LaponiteTM EP combined with AttagelTM as thickening agent against the control with RhodopolTM (xanthan) only, for gel containing copper-mesotrione.
  • Table 34 shows the Casson yield stress and the infinite viscosity obtained from the fit of the flow ramp up by a Casson model.
  • FIG. 35 Strain oscillation results are presented in Table 35 for all formulations.
  • Figure 32 shows G’ obtained during the strain oscillations for LaponiteTM EP combined with BentopharmTM as thickening agent compared to the control sample with RhodopolTM (xanthan) for gel containing copper-mesotrione.
  • Figure 33 shows G’ during the strain oscillations for LaponiteTM EP combined with AttagelTM as thickening agent compared to the control sample with RhodopolTM (xanthan) for gel containing copper-mesotrione.
  • a gel could be obtained using xanthan 2g/L on its own when using copper-mesotrione as active ingredient.
  • a gel could be formed using a combination of LaponiteTM EP and BentopharmTM or LaponiteTM EP and AttagelTM.
  • the synergistic effect was much higher when combining LaponiteTM EP and BentopharmTM than when combining LaponiteTM EP and AttagelTM.
  • a weak gel was formed using AttagelTM, this may not be strong enough to prevent the sedimentation of the active ingredient despite the highest possible concentration of AttagelTM and LaponiteTM EP being used.
  • Combining LaponiteTM EP and BentopharmTM provides gels with different strengths depending on the concentration of the two clay ingredients.
  • Example 11 Comparison with the use of LaponiteTM RD and Bentopharm as thickening agent of Suspension Concentrate containing azoxystrobin. Product used for this study
  • Millbase containing azoxystrobin as active ingredient and anionic dispersant used corresponds to the batch OP I001 -006-001
  • Millbase #1 (comprising an anionic dispersant, 6% by mass MorwetTM D425, and an active ingredient, the fungicide Azoxystrobin at 50% by mass dispersed in water)
  • LaponiteTM RD is not suitable for the formulation of suspension concentrate containing azoxystrobin and anionic dispersant: the yield stress is too low to prevent sedimentation of the active ingredient. Although the elastic modulus is acceptable, the critical strain is too high. Hence, the gel stays stable at strains where some molecular rearrangements are expected. Similar results were found when using LaponiteTMB (Laponite containing inorganic fluoro compounds according to BYK). In fact, the flow ramp experiment performed in presence of Millbase #1 containing Azoxystrobin shows that the combination of LaponiteTM B and BentopharmTM features a low Casson yield stress (below 2 Pa) even with 20g/L of BentopharmTM compared to LaponiteTM EP and BentopharmTM. No significant difference was found on the elastic and loss modulus between the use of LaponiteTM EP or LaponiteTM B combined with BentopharmTM in presence of Azoxystrobin.
  • LaponiteTM EP or LaponiteTM B relating to the stability of the gel were observed with time.
  • Example 12 Thermal characterization of LaponiteTM RD and Laponite TMEP
  • TGA Thermal gravimetric analysis
  • DSC Differential scanning calorimetry
  • Figure 34 presents the mass loss obtained from TGA.
  • Figure 35 shows the 1st heat flow curves from the DSC analysis. Note that for all heat flow curves, exotherms point upward.
  • Curves of the heat flow curve obtained from the DSC experiments are in line with the one obtained from TGA and show an endothermic peak between 100°C and 120°C for both LaponiteTM RD and LaponiteTM EP accompanied by a loss of mass.
  • This endothermic peak corresponds to the loss of water in the interlayer of the clay which is weakly bound to it according to Green et al. 1970, M. Silva et al. 2019 and Daniel et al. 2008.
  • Figure 34 reveals a graduate loss of mass from 150°C to about 700 °C for LaponiteTM RD and from about 300°C to 700°C for LaponiteTM EP which may correspond to further loss of the interlayer water according to the authors quoted above.
  • the DSC heat flow curve of LaponiteTM EP shows an exothermic peak at about 293.86°C. This may be due to some decomposition of the organic matter coating the surface of laponite.
  • Guimaraes et al. (2006) and Gonzalvez et al. (2017) also reported such exothermic peak on grafted laponite.
  • Results Figure 36 shows the spectrum obtained from the CP-MAS 13 C NMR of LaponiteTM EP.
  • the spectra reveals 4 peaks.
  • Hunt et al. 1990 identified such peaks on various metal carboxylate complexes.
  • the high intensity of the peak suggests that the coating features more than one -CH2 - group.

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Abstract

The invention relates to a particle gel comprising particles of a first clay, particles of a second clay and a liquid phase, wherein the second clay is different from the first clay and the second clay comprises an organic modification.

Description

CLAY COMPOSITIONS
FIELD OF THE INVENTION
The invention provides a particle gel. The invention also provides a composition for use in agriculture, wherein the composition is obtainable by diluting a particle gel as described herein with water. The invention also provides an agrochemical formulation.
INTRODUCTION
Thickening and rheological agents have applications in a wide variety of fields, including paints, cosmetics, pharmaceuticals and agrochemicals. In certain applications, it is useful to add thickening agents that are able to maintain a stable gel structure during storage.
This is particularly advantageous when the composition comprises a dispersion of insoluble particles or emulsified active ingredients which may settle (or cream) out of suspension over time. By including thickening agents, the composition can be kept as a stable gel for several months at least with a substantially even dispersion of insoluble active ingredients.
In certain applications, such as agrochemicals, the product containing the thickening agents may require further processing before it is used. For instance, the composition may require diluting or mixing with further ingredients. In this situation, it is advantageous to use thickening agents which modify the rheology such that the composition displays non- Newtonian behaviour (so-called “shear thinning”) during storage and handling. Thus, in the absence of shear stress, the composition is a physically stable gel, but when shear stress is applied, for instance during mixing or pumping, the composition becomes less viscous and easier to work with during handling operations.
In agrochemicals, the combination of bentonite clay with the polysaccharide Xanthan gum has been used to achieve the desired rheological behaviour (see EP0665714). However, this combination has certain drawbacks. Using bentonite alone frequently provides compositions with a very thick gel structure, which are unworkable in that pumping and pouring is difficult, so a further rheological modifying agent must be added. However, Xanthan is a costly ingredient, unsuitable in highly surfactant-rich environments and furthermore is vulnerable to bacterial degradation. This creates potential storage issues in typical formulations and could lead to wastage if the composition becomes contaminated and spoiled. Additionally, the Xanthan/bentonite system is not effective in compositions with a higher ionic strength, such as compositions in which a soluble salt form of an active ingredient is dissolved. It would therefore be advantageous to develop thickening agents which provide the useful rheological properties of known compositions, but which also overcome the drawbacks in terms of cost, bacterial contamination and compatibility with surfactants and higher ionic strength (salt-containing) compositions at varying pH.
SUMMARY OF THE INVENTION
The inventors have discovered that certain clay materials and combinations of clay materials overcome the drawbacks with existing compositions discussed above.
The use of a specific formulation containing two clays that work synergistically to achieve the same rheological response as the formulation containing xanthan and bentonite clay currently used. There is a synergistic effect between both clays: the response of both clays cannot be mimicked by just increasing the concentration of one of them. The rheological properties such as the viscosity, the yield stress and the elastic and loss modulus, are similar to those of known formulations. The new formulations using two clays enables the formation of a shear-thinning gel (hence having low viscosity at high shear rate), while having a yield stress, an elastic and loss modulus suitable to prevent sedimentation/creaming of the pesticides. The yield stress of this new gel is also high enough to keep the gel intact when submitted to low shear rate but low enough to allow the gel to flow easily.
The invention is also based on the discovering that a particular type of clay having an organic modification, in combination with an active ingredient in salt form also has the desired rheological properties outlined above. Compositions of this type overcome the aforementioned disadvantages with formulating soluble salts of active ingredients.
Further, insoluble active ingredients, e.g. particles or emulsions, can also be added which remain in stable suspension.
The interaction between the clay materials and the various other ingredients present in the compositions described herein are complex and difficult to predict with any degree of reliability. The inventors have found that the advantageous results described above are only when a specific combination of clay materials or a specific clay are used.
Because the compositions of the invention are based on largely inorganic clay materials as thickening agents, the risk of bacterial degradation mentioned above is avoided in this regard. In view of this, the compositions of the invention have lower manufacturing costs and an increased shelf-life, whilst still maintaining the desired rheological properties (elastic and loss moduli, viscosity and yield stress) as known Xanthan/bentonite compositions. This is useful in agrochemical applications where a product may be stored for some time prior to dilution and use (e.g. as a crop spray). Additionally, the compositions of the invention provide the desired rheological properties at ionic strengths which permit the incorporation of additional soluble ingredients in salt form as well as the addition of desirable surfactants. Thus, the compositions of the invention open up new possibilities in terms of new combinations of active ingredients and could contribute to the new products containing new active substances. The present invention may also find use in other fields such as pharmaceutics, food, cosmetics and paint, where particular rheological properties are desired.
The invention therefore provides a particle gel comprising particles of a first clay, particles of a second clay and a liquid phase, wherein the second clay is different from the first clay and the second clay comprises an organic modification.
The invention also provides a process for producing a composition for use in agriculture, which process comprises diluting a particle gel as described herein with water.
The invention also provides a composition for use in agriculture, wherein the composition is obtainable by diluting a particle gel as described herein with water.
The invention also provides a composition comprising a bentonite clay and a hectorite clay, wherein the hectorite clay comprises an organic modification.
The invention also provides an agrochemical formulation comprising
(a) a hectorite clay which comprises an organic modification, and (b) one or more active ingredients, wherein at least one of the active ingredients is an agrochemical.
The invention also provides the use of a particle gel as described herein, a composition as described herein, or an agrochemical formulation as described herein, as a plant protection product.
BRIEF DESCRIPTION OF THE FIGURES
Figures 1 and 2 show flow ramp results for azoxystrobin SC #1 using Laponite™ EP 5g/L Bentopharm™ B20 15 g/L, or Laponite™ EP 5g/L Bentopharm™ B2020 g/L as thickener in the presence of an anionic dispersant. Figure l is a plot of stress (Pa) vs shear rate (s-1) whilst Figure 2 is a plot of viscosity (Pa.s) vs shear rate (s-1). Two tests (called 1st test and 2nd test) were carried out on two different samples both made the same way to determine the reproducibility of the results. The experiment on the second test was performed seven days after making the sample.
Figure 3 shows strain oscillation results for azoxystrobin SC #1 using Laponite™ EP 5g/L Bentopharm™ B20 15 g/L, or Laponite™ EP 5g/L Bentopharm™ B2020 g/L as thickener in the presence of an anionic dispersant as a plot of G’, G” (Pa) vs strain (%). Two tests (called 1st test and 2nd test) were carried out on two different samples both made the same way to determine the reproducibility of the results. The experiment on the second test was performed seven days after making the sample.
Figure 4 shows frequency oscillation results for azoxystrobin SC #1 with Laponite™ EP 5g/L Bentopharm™ B20 15 g/L, or Laponite™ EP 5g/L Bentopharm™ B2020 g/L in the presence of an anionic dispersant as a plot of G’, G” (Pa) vs frequency (Hz). Data where d>90° are not taken into account.
Figure 5 shows flow ramp results for the storage study for azoxystrobin SC #1 with Laponite™ EP 5g/L Bentopharm™ 15 g/L or Laponite™ EP 5g/L Bentopharm™ 20 g/L (with anionic dispersant) which were stored for four weeks at 40°C, as a plot of stress (Pa) vs shear rate (s-1). Figure 6 shows strain oscillation results for the storage study for azoxystrobin SC #1 with Laponite™ EP 5g/L Bentopharm™ 15 g/L or Laponite™ EP 5g/L Bentopharm™ 20 g/L (with anionic dispersant) which were stored for four weeks at 40°C, as a plot of G’, G” (Pa) vs strain (%).
Figures 7 and 8 show flow ramp results for azoxystrobin SC #2 (with non-ionic dispersant), azoxystrobin SC #1 (with anionic dispersant) and for an azoxystrobin SC#2 using Laponite™ EP 5.5g/L Bentopharm™ 20 g/L. Figure 7 is a plot of stress (Pa) vs shear rate (s-1); Figure 8 is a plot of viscosity (Pa.s) vs shear rate (s-1).
Figure 9 shows strain oscillation results for azoxystrobin SC #2 with non-ionic dispersant (Rhodopol™ 23 at 3 g/L, Bentopharm™ B20 at 30 g/L, control number 2), azoxystrobin SC #2 with non-ionic dispersant (Rhodopol™ 23 2 g/L, Bentopharm™ B2025 g/L, control number 1), azoxystrobin SC #1 with anionic dispersant (Rhodopol™ 23 2 g/L, Bentopharm™ B2025 g/L) and for an azoxystrobin SC #2 using Laponite™ EP 5.5g/L Bentopharm™ B2020 g/L (with non-ionic dispersant) as a plot of G’, G” (Pa) vs strain (%). Rhodopol™ is a commercially available xanthan-based thickener.
Figure 10 shows frequency oscillation results for azoxystrobin SC #1 (formulation with anionic dispersant) and for an azoxystrobin SC #2 with non-ionic dispersant using Laponite™ EP 5.5g/L Bentopharm™ 20 g/L as a plot of G’, G” (Pa) vs frequency (Hz).
Figure 11 shows flow ramp results for the storage study on azoxystrobin SC #2 using Laponite™ EP 5.5g/L Bentopharm™ 20 g/L (with non-ionic dispersant) after storage for four weeks at 40°C as a plot of stress (Pa) vs shear rate (s-1).
Figure 12 shows strain oscillation results for the storage study on azoxystrobin SC #2 with Laponite™ EP 5.5g/L Bentopharm™ 20 g/L (with non-ionic dispersant) after storage for four weeks at 40°C as a plot of G’, G” (Pa) vs strain (%).
Figure 13 shows the results of an aging study on samples of Laponite™ EP 2% (w/w) and Laponite™ RD 5% (w/w) as plot of G’, G” (Pa) vs time (s). Figure 14 shows the strain oscillation results for the pH study (samples of Laponite™ EP 5g/L + Bentopharm™ 20g/L at the unmodified pH of 8.96 and Laponite™ EP 5g/L + Bentopharm™ 20g/L adjusted to pH 4) as a plot of G’, G” (Pa) vs strain (%).
Figure 15 shows flow ramp results for the pH study (samples of Laponite™ EP 5g/L + Bentopharm™ 20g/L at the unmodified pH of 8.96 and Laponite™ EP 5g/L + Bentopharm™ 20g/L adjusted to pH 4) as a plot of stress (Pa) vs shear rate (s-1) (left hand side) and viscosity (Pa.s) vs shear rate (s-1) (right hand side).
Figure 16 shows the strain oscillation results for the pH study (samples of Laponite™ RD 15g/L + Bentopharm™ 20g/L at the unmodified pH of 9.67 and Laponite™ RD 15g/L + Bentopharm™ 20g/L adjusted to pH 4) as a plot of G’, G” (Pa) vs strain (%).
Figure 17 shows flow ramp results for the pH study (samples of Laponite™ RD 15g/L + Bentopharm™ 20g/L at the unmodified pH of 9.67 and Laponite™ RD 15g/L + Bentopharm™ 20g/L adjusted to pH 4) as a plot of stress (Pa) vs shear rate (s-1) (left hand side) and viscosity (Pa.s) vs shear rate (s-1) (right hand side).
Figure 18 shows strain oscillation results for Laponite™ EP 5g/L + Bentopharm™ 20g/L with various concentrations of MgCh as a plot of G’, G” (Pa) vs strain (%).
Figure 19 shows flow ramp results for Laponite™ EP 5g/L + Bentopharm™ 20g/L with various concentrations of MgCh as a plot of stress (Pa) vs shear rate (s-1) (left hand side) and viscosity (Pa.s) vs shear rate (s-1) (right hand side).
Figure 20 shows strain oscillation results for Laponite™ RD 15g/L + Bentopharm™ 20g/L with various concentrations of MgCh as a plot of G’, G” (Pa) vs strain (%).
Figure 21 shows flow ramp results for Laponite™ RD 15g/L + Bentopharm™ 20g/L with various concentrations of MgCh as a plot of stress (Pa) vs shear rate (s-1) (left hand side) and viscosity (Pa.s) vs shear rate (s-1) (right hand side). Figure 22 shows strain oscillation results for Laponite™ EP 5g/L + Bentopharm™ 20g/L with various concentrations of Tween 20 as a plot of G’, G” (Pa) vs strain (%).
Figure 23 shows flow ramp results for Laponite™ EP 5g/L + Bentopharm™ 20g/L with various concentrations of Tween 20 as a plot of stress (Pa) vs shear rate (s-1) (left hand side) and viscosity (Pa.s) vs shear rate (s-1) (right hand side).
Figure 24 shows strain oscillation results for Laponite™ RD 15g/L + Bentopharm™ 20g/L with 1% or 10% Tween 20 as a plot of G’, G” (Pa) vs strain (%).
Figure 25 shows flow ramp results for Laponite™ RD 15g/L + Bentopharm™ 20g/L with 1% or 10% Tween 20 as a plot of stress (Pa) vs shear rate (s-1) (left hand side) and viscosity (Pa.s) vs shear rate (s-1) (right hand side).
Figure 26 shows strain oscillation results for the formulation of an azoxystrobin SC #1 (with anionic dispersant) using Laponite™ EP as thickening agent either at 5g/L, lOg/L or at 5g/L in combination with Bentopharm™ 20g/L as a plot of G’, G” (Pa) vs strain (%).
Figure 27 shows flow ramp results for the formulation of an azoxystrobin SC #1 (with anionic dispersant) using Laponite™ EP as thickening agent either at 5g/L, lOg/L or at 5g/L in combination with Bentopharm™ 20g/L as a plot of stress (Pa) vs shear rate (s-1) (left hand side) and viscosity (Pa.s) vs shear rate (s-1) (right hand side).
Figure 28 shows the strain oscillation results for Laponite™ EP 5g/L, Laponite™ EP lOg/L, Bentopharm 20g/L, Bentopharm 40g/L and Laponite™ EP 5g/L + Bentopharm™ 20g/L as a plot of G’ (Pa) vs strain (%) (top) and a plot of G” (Pa) vs strain (%) (bottom), from example 9.
Figure 29 shows the results of the flow ramp test results for Laponite™ EP 5g/L, Laponite™ EP lOg/L, Bentopharm 20g/L, Bentopharm 40g/L and Laponite™ EP 5g/L + Bentopharm™ 20g/L as a plot of stress (Pa) vs shear rate (s-1) (top) and viscosity (Pa.s) vs shear rate (s-1) (bottom), from example 9. Figure 30 shows the stress versus strain rate curve (top) and the viscosity versus strain rate curve (bottom) for Laponite™ EP combined with Bentopharm™ as thickening agent against the control with Rhodopol™ (xanthan) only, for gel containing copper-mesotrione, in example 10.
Figure 31 shows stress versus strain rate curve (top) and the viscosity versus strain rate curve (bottom) for Laponite™ EP combined with Attagel™ as thickening agent against the control with Rhodopol™ (xanthan) only, for gel containing copper-mesotrione, in example 10
Figure 32 shows G’ obtained during the strain oscillations for Laponite™ EP combined with Bentopharm™ as thickening agent compared to the control sample with Rhodopol™ (xanthan) for gel containing copper-mesotrione, in example 10.
Figure 33 shows G’ during the strain oscillations for Laponite™ EP combined with Attagel™ as thickening agent compared to the control sample with Rhodopol™ (xanthan) for gel containing copper-mesotrione, in example 10.
Figure 34 presents the mass loss obtained from thermogravimetric analysis (TGA) for Laponite™ EP and Laponite™ RD in example 12.
Figure 35 shows the first heat flow curves from the differential scanning calorimetry (DSC) analysis for Laponite™ EP and Laponite™ RD in example 12. Note that for the heat flow curves, exotherms point upward.
Figure 36 shows the spectrum obtained from the CP-MAS 13C NMR of Laponite™ EP, from example 13.
DETAILED DESCRIPTION
Definitions
The term “particle gel” is known in the art, and takes its normal meaning herein.
Sometimes such compositions are referred to as “colloidal gels”. Thus, a particle gel may be gel comprising a dispersed solid and/or liquid particle phase intertwined with a continuous liquid phase. Typically, the particle gel is a gel comprising a dispersed solid particle phase intertwined with a continuous liquid phase.
A “house of cards structure” is known in the art, and takes its normal meaning herein.
Thus, the term refers to an extended network of particles linked by edge-edge, edge-face and face-face interactions. House of cards structures are discussed in Luckham, Paul F., and Rossi, Sylvia. "The colloidal and rheological properties of bentonite suspensions", Advances in colloid and interface science 82.1-3 (1999): 43-92).
The term “microparticle”, as used herein, means a microscopic particle whose size is typically measured in micrometres (pm). A microparticle usually has a particle size of greater than 0.1 pm, and more typically has a particle size of greater than 0.5 pm, preferably more than 1 pm. The particle size of a microparticle is typically up to 1000 pm, typically up to 500 pm. Often, however, a microparticle has a particle size of from 1 to 100 pm.
The term “nanoparticle”, as used herein, means a microscopic particle whose size is typically measured in nanometers (nm). A nanoparticle typically has a particle size of from 0.1 nm to 1000 nm, for instance from 1 to 750 nm or from 5 to 500 nm.
The term “room temperature”, as used herein, refers to the conventional definition of room temperature of between 15 and 25°C.
The term “smectite” as used herein is known in the art, and takes its normal meaning herein. Typically, a smectite is a naturally occurring silicate-based mineral composed of four atomic planes of oxygen atoms that are cross-linked primarily by silicon in tetrahedral interstices and other metallic elements (e.g., lithium, magnesium, and aluminum) in the octahedral sites. The residual negative charge on the layers is balanced by exchangeable hydrated cations (denoted Mn+,xH20) that reside in the gallery region between the layers (see T.J. Pinnavaia, in Encyclopedia of Materials: Science and Technology, 2001). Clay materials in general, including those discussed herein, are described in Bergaya, Faiza, and Gerhard Lagaly. Handbook of clay science. Newnes, 2013. The term “montmorillonite” as used herein is known in the art, and takes its normal meaning herein. A montmorillonite clay is a member of the smectite group, and is typically a 2:1 clay, meaning that it has two tetrahedral sheets of silica sandwiching a central octahedral sheet of alumina and is characterized as having greater than 50% octahedral charge.
The term “bentonite” as used herein is known in the art, and takes its normal meaning herein. Bentonite is an absorbent aluminium phyllosilicate clay comprising montmorillonite.
The term “hectorite” as used herein is known in the art, and takes its normal meaning herein. Thus, a hectorite clay may be found naturally. In the context of the present invention this term is also used to refer to both natural and synthetic forms of this type of clay (“synthetic hectorites”), for instance commercially available synthetic hectorite-type materials such as Laponite™, which is a type of “synthetic hectorite”.
The term “synthetic clay” as used herein is known in the art, and takes its normal meaning herein. Thus, the term refers to a clay synthesised by humans, rather than formed as the result of natural geological processes.
Particle gel composition
The present invention provides a particle gel comprising particles of a first clay, particles of a second clay and a liquid phase, wherein the second clay is different from the first clay and the second clay comprises an organic modification.
Typically, the particles of the first clay and the particles of the second clay form a house of cards structure. Thus, the particles of the first clay and the particles of the second clay interact with each other to produce a single network formed from both types of clay particles. Typically, the particles of the first clay are platelets and the particles of the second clay are platelets. Thus, the particle gel may comprise a single network formed from both the particles of the first clay and the particles of the second clay, wherein the particles of the first clay are platelets and the particles of the second clay are platelets. The particles of the first clay and the particles of the second clay may exhibit edge-edge, edge- face and/or face-face interactions. Typically, the particles of the first clay and the particles of the second clay exhibit edge-edge, edge-face and face-face interactions.
Rheological properties
Typically, the particle gel is a non-Newtonian fluid. For instance, the viscosity of the particle gel usually decreases upon application of a force. Thus, typically, the particle gel is a shear-thinning fluid. The particle gel may be thixotropic. Thixotropic materials display time-dependent shear thinning behaviour. For instance, thixotropic materials take a finite time to attain equilibrium viscosity when introduced to a change in shear rate.
Typically, the yield stress of the particle gel is from 1 to 10 Pa, for instance from 1 to 5 Pa. Typically, the particle gel has a yield stress of from 1 to 10 Pa, preferably from 1 to 5 Pa at room temperature. The yield stress is the stress that must be applied to make the gel flow. The skilled person would be well aware of a method for determining the yield stress of a composition. For instance, an approximate yield stress measurement can be gained by plotting the shear stress values for a range of shear rates, fitting a curve to the data, and extrapolating through the stress axis. The intersect on the stress axis gives the yield stress. It may be useful to use a rheological mathematical model, such as the Casson model (see Rao, M. Anandha. "Flow and functional models for rheological properties of fluid foods." Rheology of fluid, semisolid, and solid foods. Springer, Boston, MA, 2014. 27-61).
Typically, the infinite viscosity of the particle gel determined using a fit of the stress vs strain rate curve using a Casson model is less than 100 mPa.s. For instance, the infinite viscosity of the particle gel determined using a fit of the stress vs strain rate curve using a Casson model may be less than 75 mPa.s, less than 50 mPa.s or less than 25 mPa.s. Typically, the infinite viscosity of the particle gel determined using a fit of the stress vs strain rate curve using a Casson model is at least 1 mPa.s, for instance at least 5 mPa.s. Typically, the infinite viscosity of the particle gel determined using a fit of the stress vs strain rate curve using a Casson model is between 1 and 100 mPa.s, for instance between 1 and 50 mPa.s, preferably between 5 and 25 mPa.s. Unless mentioned otherwise, all infinite viscosity values refer to the infinite viscosity at room temperature, as defined herein.
It may be desirable that the particle gel of the invention displays a particular viscosity at a particular shear rate. Thus, the viscosity of the particle gel of the invention can readily be modified by subject in it to a specific shear rate. This might be useful when the particle gel is mixed with further ingredients or diluted. Unless mentioned otherwise, the viscosity values refer to the viscosity at room temperature, as defined herein. Typically, the viscosity of the particle gel at a shear rate of 20 s-1 is less than 450 mPa.s, preferably less than 420 mPa.s. Typically, the viscosity of the particle gel at a shear rate of 10 s-1 is less than 700 mPa.s, preferably less than 500 mPa.s. Thus, the particle gel may be a particle gel that exhibits a viscosity of less than 420 mPa.s at a shear rate of 20 s-1 and of less than 700 mPa.s at a shear rate of 10 s-1.
Typically, the elastic modulus G' of the particle gel is between 10 and 50 Pa, preferably between 10 and 40 Pa. The critical strain (ycritic) of the particle gel is typically between 0.005 and 0.1 (0.5% and 10%), for instance between 0.005 and 0.05 (0.5 and 5%), typically between 0.005 and 0.02 (0.5 and 2%). Preferably, the critical strain (ycritic) of the particle gel is about 0.01 (about 1 %). The elastic modulus G’ and the critical strain may be determined on the linear viscosity range whose the limit was found using the Lissajous (torque vs displacement) plot or applying a 5% threshold compared to the value obtained in the linear viscoelastic range. Unless mentioned otherwise, the viscoelasticity properties are measured at room temperature, wherein room temperature is as defined herein.
Determination of the viscosity parameters discussed above may be performed using a controlled stress rheometer. The yield stress and the infinite viscosity may be determined by doing a flow ramp and fitting the curves with a Casson model (see Rao, M. Anandha. "Flow and functional models for rheological properties of fluid foods." Rheology of fluid, semisolid, and solid foods. Springer, Boston, MA, 2014. 27-61). Here, the flow ramp up curve was fitted with the Casson model to determine the infinite viscosity and the yield stress. Typically the flow ramp up curve is measured at increasing shear speeds from 0 to 600 s-1. Further details on the rheological measurements used to provide flow ramp data to input into the Casson model may be found in the rheological test protocol as set out for Example 1. The viscosity at a particular shear rate may be determined by looking at the values obtained during the flow ramp up at such a shear rate. The elastic modulus G’ and critical strain may be determined by performing a strain oscillatory test. The linear viscoelastic range may be determined using the Lissajous plot and/or the 5% threshold.
Typically, the particle gel according the invention fulfils at least two of the following criteria, for instance at least three of the following criteria, at least four of the following criteria or at least five of the following criteria: the yield stress of the particle gel is from 1 to 10 Pa; the infinite viscosity of the particle gel determined using a fit of the stress us strain rate curve using a Casson model is less than 100 mPa.s; the viscosity of the particle gel at a shear rate of 20 s-1 is less than
420 mPa.s; the viscosity of the particle gel at a shear rate of 10 s-1 is less than 700 mPa.s; the elastic modulus G' determined on the linear viscoelastic range of the particle gel is between 10 and 50 Pa; the critical strain (ycritic) of the particle gel is about 0.01.
Preferably, the particle gel has all of the following properties: the yield stress of the particle gel is from 1 to 10 Pa; the infinite viscosity of the particle gel determined using a fit of the stress s strain rate curve using a Casson model is less than 100 mPa.s; the viscosity of the particle gel at a shear rate of 20 s-1 is less than 420 mPa.s; the viscosity of the particle gel at a shear rate of 10 s-1 is less than 700 mPa.s; the elastic modulus G' determined on the linear viscoelastic range of the particle gel is between 10 and 50 Pa; and the critical strain (ycritic) of the particle gel is about 0.01. First clay
Typically, the particles of the first clay are microparticles. For instance, the particles of the first clay may have an average particle size of at least 1 pm. Typically, the particles of the first clay have an average particle size of less than 1000 pm, for instance less than 500 pm, less than 250 pm or less than 100 pm. The particles of the first clay may have a particle size of from 1 pm to 100 pm, typically from 1 pm to 50 pm, from 1 pm to 25 pm, preferably from 1 to 10 pm. Typically, the particles of the first clay are in the form of platelets. Thus, typically the particles of the first clay are platelets having an average particle size (maximum diameter i.e. the greatest edge to edge distance across the platelet) of at least 1 pm. Typically, the particles of the first clay are platelets having an average particle size of less than 1000 pm, for instance less than 500 pm, less than 250 pm or less than 100 pm. The particles of the first clay may be platelets having a particle size of from 1 pm to 100 pm, typically from 1 pm to 50 pm, from 1 pm to 25 pm, preferably from 1 to 10 pm.
The average particle size may be determined by microscopy, for instance by scanning electron microscopy (SEM) or transmission electron microscopy (TEM).
The first clay may be a water-swellable clay. Typically, the first clay is a naturally occurring clay. Typically, the first clay comprises a smectite, preferably a naturally occurring smectite, preferably montmorillonite. Preferably the first clay comprises a sodium montmorillonite. Thus, the first clay may be bentonite. For instance, the first clay may be Bentopharm™, for instance Bentopharm™ B20 grade. At the time of filing, Bentopharm™ is commercially available from Wilfrid Smith Ltd.
Typically, the first clay does not comprise an organic modification. In other words, the first clay is typically a purely inorganic material, without any organic groups incorporated into the bulk and/or grafted or adsorbed onto the surface.
The first clay may impart shear-thinning properties when mixed with a liquid phase in the absence of the second clay. However, typically compositions comprising the first clay in the absence of the second clay form a very thick gel which is difficult for a consumer to handle after storage at elevated temperatures (for example, 40°C for 4 weeks). Typically, the concentration of the first clay is not more than 25% by weight of the particle gel, not more than 20% by weight of the particle gel, not more than 15% by weight of the particle gel or not more than 10% by weight of the particle gel. The concentration of the first clay may be at least 0.01% by weight of the particle gel, for instance at least 0.05% by weight of the particle gel, preferably at least 0.1% by weight of the particle gel. For instance, the concentration of the first clay may be between 0.01 and 10% by weight of the particle gel, preferably between 0.1 and 5% by weight of the particle gel. Thus, the concentration of the first clay may be about 0.5% by weight of the particle gel, about 1% by weight of the particle gel, about 1.5% by weight of the particle gel, about 2% by weight of the particle gel, about 2.5% by weight of the particle gel, about 3% by weight of the particle gel, about 3.5% by weight of the particle gel, about 4% by weight of the particle gel, about 4.5% by weight of the particle gel or about 5% by weight of the particle gel. Preferably, the concentration of the first clay is between 0.5 and 3% by weight of the particle gel.
Second day/organic modification
Typically, the particles of the second clay are nanoparticles. Thus, the particles of the second clay typically have an average particle size of less than 1 pm (1000 nm), usually from 0.1 nm to 1000 nm. The particles of the second clay may have an average particle size of less than 750 nm, less than 500 nm, less than 250 nm, typically less than 100 nm or less than 50 nm. The particles of the second clay may have an average particle size of at least 1 nm, at least 5 nm or at least 10 nm. Thus, the particles of the second clay may have an average particle size of from 1 to 250 nm, or from 5 to 100 nm, preferably from 10 to 50 nm. The particles of the second clay may have an average particle size of about 25 nm.
Typically, the particles of the second clay are in the form of platelets, typically nanoplatelets. Thus, the particles of the second clay may be platelets having an average particle size (maximum diameter i.e the greatest edge to edge distance across the platelet) of less than 1 pm (1000 nm), usually from 0.1 nm to 1000 nm. The particles of the second clay may be platelets having an average particle size of less than 750 nm, less than 500 nm, less than 250 nm, typically less than 100 nm or less than 50 nm. The particles of the second clay may be platelets having an average particle size of at least 1 nm, at least 5 nm or at least 10 nm. Thus, the particles of the second clay may be platelets having an average particle size of from 1 to 250 nm, or from 5 to 100 nm, preferably from 10 to 50 nm. The particles of the second clay may be platelets having an average particle size of about 25 nm.
The second clay may impart shear-thinning properties when mixed with a liquid phase in the absence of the first clay. Indeed, in another aspect of the invention, certain formulations comprising the second clay only (i.e. without the first clay) are provided, as described herein.
The second clay comprises a clay material different to the first clay, an organic modification and optionally water, for instance water molecules trapped within the layers of the clay material. The clay material in the second clay may be a water-swellable clay. Typically, the second clay is a smectite with an organic modification, preferably a hectorite with an organic modification. In other words, the clay material in the second clay may be a smectite, preferably a hectorite. Typically, the second clay comprises a synthetic clay.
In other words, the clay material in the second clay may be a synthetic clay. Thus, the second clay may be a synthetic hectorite with an organic modification. The organic modification forms a part of the particles of the second clay. Thus, the second clay typically comprises a clay material different to the first clay (preferably a hectorite, more preferably a synthetic hectorite), an organic modification and optionally water.
The organic modification may be a bulk modification or a surface modification. Alternatively, the organic modification may be present in both the bulk and on the surface of the clay material.
The organic modification is preferably a hydrophilic organic modification. Thus, the second clay may be a synthetic hectorite clay with a hydrophilic organic modification.
Suitable hydrophilic organic modifications include organic compounds comprising carbonyl groups, for instance organic compounds comprising acetate groups. For instance, the hydrophilic organic modifications may comprise an anionic polymer. The hydrophilic organic modification may comprise a surfactant. The hydrophilic organic modification may comprise an organic compound comprising a carboxylate anion, for instance a metal carboxylate.
Typically, the second clay comprises less than 95% by weight clay material, for instance less than 90% by weight clay material, less than 85% by weight clay material or less than 80% by weight clay material. Typically, the second clay comprises at least 50% by weight clay material, at least 60% by weight clay material preferably at least 70% by weight clay material. Thus, the second clay typically comprises from 50 to 95% by weight clay material, or from 60 to 85% by weight clay material, preferably from 70 to 80% clay material.
Typically, the second clay comprises less than 40% by weight of the organic modification, less than 30% by weight of the organic modification, preferably less than 20% by weight of the organic modification. The second clay may comprise at least 1% by weight organic modification, at least 5% by weight organic modification or at least 10% by weight organic modification. Thus, the second clay may comprise from 1 to 40% by weight organic modification, from 5 to 30% by weight organic modification preferably from 10 to 20% by weight organic modification.
Typically, the second clay comprises water. The second clay may comprise from 1 to 30% by weight water, from 1 to 20% by weight water, preferably from 5 to 15% by weight water. Thus, the second clay may comprise from 60 to 85% by weight clay material, from 5 to 30% by weight organic modification and from 1 to 20% by weight water. Preferably, the second clay comprises from 70 to 80% clay material, from 10 to 20% by weight organic modification and from 5 to 15% by weight water.
The content of clay material, organic modification and water may be determined using thermogravimetric-gas chromatography-mass spectrometry (TGA-GC-MS).
The percentages by weight of certain elements in the second clay may be determined using TGA-GC-MS and elemental analysis. For instance, TGA-GC-MS and elemental analysis may show the presence of carbon indicating the presence of the organic modification. Typically, when subjected to TGA-GC-MS and elemental analysis, the second clay comprises from 0.5% to 30% by weight carbon, for instance from 1 to 25% by weight carbon, from 5 to 20% by weight carbon, preferably from 5 to 15% by weight carbon. Typically, when subjected to TGA-GC-MS and elemental analysis, the second clay comprises from 0.5% to 30% by weight carbon, from 1% to 10% by weight hydrogen, up to 5% by weight nitrogen, from 1% to 20% by weight magnesium, from 10% to 40% by weight silicon, from 0.01% to 1% by weight calcium, from 0.1% to 10% by weight sodium and from 0.01% to 1% by weight lithium. For instance, when subjected to TGA-GC-MS and elemental analysis, the second clay may comprise from 5% to 15% by weight carbon, from 1% to 5% by weight hydrogen, from 0.1 to 2% by weight nitrogen, from 5% to 15% by weight magnesium, from 15% to 30% by weight silicon, from 0. 1% to 0.5% by weight calcium, from 0.5% to 5% by weight sodium and from 0.05% to 0.5% by weight lithium.
Preferably the second clay is Laponite™ EP. At the time of filing, Laponite™ EP is commercially available from BYK at https://www.byk.com/en/additives/additives-by- name/1 aponite-ep . php .
Typically, the concentration of the second clay is not more than 15% by weight of the particle gel, not more than 10% by weight of the particle gel, or not more than 5% by weight of the particle gel. The concentration of the second clay may be at least 0.01% by weight of the particle gel, for instance at least 0.05% by weight of the particle gel. For instance, the concentration of the second clay may be between 0.01 and 5 % by weight of the particle gel, preferably between 0.05 and 3% by weight of the particle gel. Thus, the concentration of the second clay may be about 0.1% by weight of the particle gel, about 0.5% by weight of the particle gel, about 1% by weight of the particle gel, about 1.5% by weight of the particle gel, about 2% by weight of the particle gel, about 2.5% by weight of the particle gel, or about 3% by weight of the particle gel. Preferably, the concentration of the first clay is about 0.5% by weight of the particle gel.
Combinations
Usually, the average particle size of the particles of the first clay is larger than that of the particles of the second clay. For instance, the particles of the first clay may be microparticles and the particles of the second clay may be nanoparticles. Thus, the average particle size of the particles of the first clay may be from 1 to 1000 pm and the average particle size of the particles of the second clay may be from 0.1 to 1000 nm. The average particle size of the particles of the first clay may be from 1 to 100 pm and the average particle size of the particles of the second clay may be from 1 to 250 nm. The average particle size of the particles of the first clay may be from 1 to 150 pm and the average particle size of the particles of the second clay may be from 5 to 100 nm. Preferably, the average particle size of the particles of the first clay may be from 1 to 10 pm and the average particle size of the particles of the second clay may be from 10 to 50 nm.
Preferably the particles of the first clay are platelets and the particles of the second clay are platelets. For instance, the particles of the first clay may be microplatelets and the particles of the second clay may be nanoplatelets. Thus, the average particle size (maximum diameter i.e. the greatest edge to edge distance across the platelet) of the platelets of the first clay may be from 1 to 1000 pm and the average particle size of the platelets of the second clay may be from 0.1 to 1000 nm. The average particle size of the platelets of the first clay may be from 1 to 100 pm and the average particle size of the platelets of the second clay may be from 1 to 250 nm. The average particle size of the platelets of the first clay may be from 1 to 50 pm and the average particle size of the platelets of the second clay may be from 5 to 100 nm. Preferably, the average particle size of the platelets of the first clay may be from 1 to 10 pm and the average particle size of the platelets of the second clay may be from 10 to 50 nm.
Typically, the first clay is a water-swellable clay and the second clay is a water-swellable clay. Generally, both the first and second clays comprise a smectite. Thus, the first clay may comprise a smectite and the second clay may comprise a smectite with an organic modification, preferably a hydrophilic organic modification. Typically, the first clay is a naturally occurring clay whilst the second clay comprises a synthetic clay. For instance the first clay may be a naturally occurring smectite whilst the second clay may comprise a synthetic smectite with an organic modification, preferably a hydrophilic organic modification.
Preferably the first clay comprises montmorillonite, typically a sodium montmorillonite. For instance, the first clay may be bentonite, e.g. Bentopharm™ supplied by Wilfrid Smith Ltd, for instance Bentopharm™ B20 grade. Preferably the second clay comprises a synthetic hectorite with an organic modification, preferably a hydrophilic organic modification. Thus, typically the first clay comprises montmorillonite and the second clay comprises a synthetic hectorite with an organic modification, preferably a hydrophilic organic modification. For instance, the first clay may comprise sodium montmorillonite and the second clay comprises a synthetic hectorite with an organic modification, preferably a hydrophilic organic modification. Thus, the first clay may be bentonite and the second clay may comprise a hectorite (typically a synthetic hectorite) with an organic modification, preferably a hydrophilic organic modification. Preferably the second clay is Laponite™ EP from BYK. Therefore, preferably the first clay is bentonite, typically Bentopharm™ B20, and the second clay is Laponite™ EP.
Typically, the first clay does not comprise an organic modification. In other words, the first clay is typically a purely inorganic material, without any organic groups incorporated into the bulk and/or grafted or adsorbed onto the surface. The second clay comprises an organic modification as described herein, typically a hydrophilic organic modification as described herein.
Typically, the concentration of the first clay is between 0.01 and 10% by weight of the particle gel and the concentration of the second clay may be between 0.01 and 5 % by weight of the particle gel. Preferably, the concentration of the first clay is between 0.1 and 5% by weight of the particle gel and the concentration of the second clay is between 0.05 and 3% by weight of the particle gel.
Liquid phase
Typically, in the particle gel of the present invention, the liquid phase comprises water. Thus, the liquid phase is typically aqueous. Further ingredients, such as surfactants, salts, anti-freeze agents and dispersants may be dissolved in the liquid phase.
Thus, the particle gel of the invention may comprise particles of a first clay, having an average particle size of 1 to 100 pm, said particles of the first clay preferably being platelets, wherein the first clay is a naturally occurring clay; particles of a second clay having an average particle size of from 1 to 250 nm, said particles of the second clay preferably being platelets, wherein the second clay is a synthetic clay comprising a hydrophilic organic modification; and a liquid phase comprising water.
The particle gel of the invention may comprise particles of a first clay, having an average particle size of 1 to 50 pm, said particles of the first clay preferably being platelets, wherein the first clay comprises a naturally occurring smectite, preferably wherein the first clay is bentonite; particles of a second clay having an average particle size of from 5 to 100 nm, said particles of the second clay preferably being platelets, wherein the second clay is a synthetic hectorite clay comprising a hydrophilic organic modification, preferably Laponite™ EP; and a liquid phase comprising water.
The particle gel of the invention may comprise particles of a first clay, having an average particle size of 1 to 10 pm, said particles of the first clay preferably being platelets, wherein the first clay comprises a naturally occurring smectite, preferably wherein the first clay is bentonite; particles of a second clay having an average particle size of from 10 to 50 nm, said particles of the second clay preferably being platelets, wherein the second clay is a synthetic hectorite clay comprising a hydrophilic organic modification, preferably Laponite™ EP; and a liquid phase comprising water.
Active ingredient
Typically, the particle gel of the invention comprises one or more active ingredients. For instance, the particle gel of the invention may comprise at least two active ingredients, at least three active ingredients or at least four active ingredients The active ingredient(s) may be any ingredient which imparts a particular utility or property to the particle gel. For instance, the active ingredient may be an agrochemical, a pigment, a pharmaceutical or a cosmetic ingredient. Typically, at least one of the active ingredients is dispersed in the particle gel or is present in the particle gel in emulsified form. In other words, at least one of the active ingredients is only partially soluble or is insoluble in the liquid phase and hence dispersible. Thus, typically, at least one of the active ingredients is only partially soluble in water, or is insoluble in water. Examples of such active ingredients include thiamethoxam, atrazine, azoxystrobin and mesotrione. When at least one of the active ingredients is present in the particle gel in emulsified form, the active ingredient is typically dissolved in an oil, for instance an alkylnaphthalene oil such as the solvent Solvesso™ 200. Examples of such active ingredients which may be present in emulsified form include S-metolachlor, prosulfocarb, trinexapac-ethyl, clomazone, tefluthrin and lambda-cyhalothrin. Typically, when at least one of the active ingredients is present in the particle gel in emulsified form the particle gel further comprises one or more surfactants, typically anionic or non-ionic surfactants, as described herein. When at least one of the active ingredients is present in the particle gel in emulsified form the particle gel may further comprise other ingredients such as one or more anti-foaming agents, for instance Dow Corning ™ antifoam MSA or Dow Coming ™ antifoam 1520.
At least one of the active ingredients may be an agrochemical. Where there are more than one active ingredients present either all or some of the active ingredients may be agrochemicals. For instance, the particle gel may comprise at least two active ingredients which are agrochemicals, at least three active ingredients which are agrochemicals or at least four active ingredients which are agrochemicals. Typically, at least one of those active ingredients (agrochemicals) is dispersed in the particle gel or is present in the particle gel in emulsified form. In other words, at least one of the active ingredients (agrochemicals) is not soluble in the aqueous liquid phase. The agrochemical may be selected from a pesticide, a fungicide, an insecticide or an herbicide, or a plant growth regulator. For instance, the agrochemical may be a fungicide which is azoxystrobin, an herbicide which is mesotrione or an insecticide which is thiamethoxam.
Typically, the concentration of the active ingredient which is not soluble in the liquid phase is from 0.1 to 60 % by weight of the particle gel, for instance from 10 to 40% by weight of the particle gel or from 5 to 20% by weight of the particle gel. The particle gel of the present invention may further comprise a salt. Typically, the salt is a salt of an active ingredient. Thus, at least one active ingredient may be a salt, typically a salt which is soluble in the liquid phase of the particle gel. Usually, the salt is a water- soluble salt. Thus, typically, the particle gel comprises at least one active ingredient which is dispersed in the particle gel or is present in the particle gel in emulsified form and at least one active ingredient which is a salt, preferably a salt which is soluble in the liquid phase of the particle gel. Alternatively, the particle gel may comprise only active ingredients which are dispersed in the particle gel or is present in the particle gel in emulsified form (i.e. which are insoluble in the liquid phase) or the particle gel may comprise only active ingredients which are salts which are soluble in the liquid phase of the particle gel.
Thus, at least one of the active ingredients may be a salt of an agrochemical, for example a pesticide, herbicide or fungicide salt. The particle gel may therefore comprise at least one active ingredient which is an agrochemical (for instance a pesticide, insecticide, herbicide or fungicide) which is dispersed in the particle gel or is present in the particle gel in emulsified form and at least one active ingredient which is a salt of an agrochemical (for instance a pesticide, insecticide, herbicide or fungicide salt, or the salt of a plant growth regulator) which is soluble in the liquid phase. Examples of agrochemicals which are soluble in the liquid phase (typically water) include glyphosate as the potassium salt, dicamba as the sodium salt, 2,4-D as the dimethylamine salt and glufosinate as the ammonium salt. The agrochemical may be a salt of a plant growth regulator, for instance a plant growth regulator which is a mepiquat halide, typically mepiquat chloride. Plant growth regulators may enhance or suppress plant growth, or direct plant growth in a particularly desired way (e.g. to increase yield of a particular product).
The salt may be an inorganic salt, for instance an alkaline or alkali earth metal salt. In this case the salt is not an active ingredient, but is present to modify the ionic strength of the particle gel. The particle gel may comprise more than one salt, for instance one salt which is a salt of an active ingredient and another salt which is an inorganic salt, for instance an alkaline or alkali earth metal salt. Examples of such salts include lithium halides, sodium halides, potassium halides, magnesium halides and calcium halides. For instance, the salt may be magnesium chloride (MgCl2) or sodium chloride (NaCl). Typically, the concentration of the salt is from 0.1 to 60% by weight of the particle gel, for instance from 0.1 to 40 % by weight of the particle gel, preferably from 5 to 30% by weight of the particle gel.
Dispersant
The particle gel of the present invention may further comprise a dispersant. Typically, the dispersant is a non-ionic or anionic dispersant. The person skilled in the art would be well aware of suitable dispersants and would be able to select a dispersant based on the particular characteristics of the particle gel. Dispersants are typically added to improve the separation of particles and to prevent settling or clumping.
For instance, the particle gel may comprise a dispersant which is an anionic dispersant. Examples of anionic dispersants include salts of alkylnaphthalenesulphates (for instance the polymeric material Morwet™ D425 from Nouryon). The particle gel may comprise a dispersant which is a non-ionic dispersant. Non-ionic dispersants include hydrophilic polymers, typically hydrophilic comb-like polymers, for instance hydrophilic methyl methacrylate graft copolymers (for instance Atlox™ 4913 from Croda).
Typically, the concentration of the dispersant is from 0.1 to 20 % by weight of the particle gel, preferably from 1% to 10% by weight of the particle gel or from 1 to 5% by weight of the particle gel.
Surfactant
The particle gel may comprise a surfactant. The person skilled in the art would be well aware of suitable surfactants and would be able to select a surfactant based on the particular characteristics of the particle gel. Surfactants are typically added to improve the stability of an emulsion, by lowering the surface tension between the liquid phase (typically aqueous) and the droplets of the emulsion (typically an oil). Surfactants may be added to improve the bio-efficacy of a leaf-applied agrochemical product. Typically, the surfactant is a non-ionic surfactant, for instance polyethylene glycol sorbitan monolaurate (such as Tween® 20), tri-styryl-phenol-ethoxylates (such as Soprophor™ BSU) and alkyl ethoxylates (such as Synperonic™Al 1 and Synperonic™NP13). Typically, the concentration of the surfactant is from 0.1 to 50% by weight of the particle gel, typically from 0.1 to 20 % by weight of the particle gel. pH
The particle gel may further comprise a pH-modifying agent. Typically, the pH of the particle gel is between 2 and 10. Thus, typically, the particle gel comprises a pH- modifying agent that imparts a pH of between 2 and 10 to the particle gel.
The pH-modifying agent may be an acid. Thus, the pH of the particle gel may be between 2 and 7, preferably between 3 and 5. For instance, the pH-modifying agent may be an acid selected from an inorganic acid such as hydrohalic acid, sulfuric acid, sulfonic acid, nitric acid, phosphoric acid, phosphonic acid, or an organic acid such as a carboxylic acid. Preferably the acid is hydrochloric acid (HC1) or acetic acid (CH3COOH).
The pH-modifying agent may be an alkali. Thus, the pH of the particle gel may be between 7 and 10. For instance, the pH-modifying agent may be an alkali selected from an inorganic alkali such as an alkali or alkaline earth hydroxide or an alkali or alkaline earth carbonate, or an organic base such as an amine.
The amount of acid or base in the particle gel may be any amount suitable to achieve the desired pH. The skilled person would readily be able to add an appropriate amount of acid or base and test the pH for instance using a pH probe or indicator paper.
Antifreeze
The particle gel according may comprise an anti-freezing agent. The person skilled in the art would be well aware of suitable anti-freezing agent and would be able to select an anti- freezing agent based on the particular characteristics of the particle gel. Anti-freezing agents are chemicals that reduce the freezing temperature of the particle gel, relative to an equivalent particle gel without the anti-freezing agent present. Typically, the anti-freezing agent is propylene glycol. Salts such as sodium chloride may also be used as anti-freezing agents. Typically, the concentration of the anti-freezing agent is from 5 to 25% by weight of the particle gel, preferably from 10 to 20% by weight of the particle gel.
The particle gel may comprise two or more, for instance three or more or four or more selected from the group consisting of a surfactant as described herein, a dispersant as described herein, a salt as described herein, a pH modifying agent as described herein and an anti-freezing agent as described herein. The particle gel may comprise a surfactant as described herein, a dispersant as described herein, a salt as described herein, a pH modifying agent as described herein and an anti-freezing agent as described herein.
Process
The invention also provides a process for producing a composition for use in agriculture, which process comprises diluting a particle gel as described herein with water. The invention also provides a composition for use in agriculture, wherein the composition is obtainable by diluting a particle gel as described herein with water.
Typically, the particle gel composition as described herein is diluted by a factor of between 1 in 10 and 1 in 1000, typically 1 part in 100 of water. For instance, the particle gel composition as described herein may be diluted by a factor of between 1 part in 10 and 1 part in 200, typically from 1 part in 25 to 1 part in 150, preferably from 1 part in 50 to 1 part in 100. Typically, the composition is diluted to enable efficient spraying across fields.
Composition
The invention also provides a composition comprising a bentonite clay and a hectorite clay, wherein the hectorite clay comprises an organic modification. The organic modification may be any organic modification as described herein. Typically, the organic modification is a hydrophilic organic modification.
Typically the hectorite clay is a synthetic hectorite clay. Thus, typically the composition comprises a bentonite clay and a synthetic hectorite clay, wherein the synthetic hectorite clay comprises a hydrophilic organic modification. The organic modification may be a bulk modification or a surface modification. Alternatively the organic modification may be present in both the bulk and on the surface of the clay material.
Suitable hydrophilic organic modifications include organic compounds comprising carbonyl groups, for instance organic compounds comprising acetate groups. For instance, the hydrophilic organic modifications may comprise an anionic polymer. The hydrophilic organic modification may comprise a surfactant. The hydrophilic organic modification may comprise an organic compound comprising a carboxylate anion, for instance a metal carboxylate.
Typically, the hectorite clay comprises less than 95% by weight clay material, for instance less than 90% by weight clay material, less than 85% by weight clay material or less than 80% by weight clay material. Typically, the hectorite clay comprises at least 50% by weight clay material, at least 60% by weight clay material preferably at least 70% by weight clay material. Thus, the hectorite clay typically comprises from 50 to 95% by weight clay material, or from 60 to 85% by weight clay material, preferably from 70 to 80% clay material.
Typically, the hectorite clay comprises less than 40% by weight of the organic modification, less than 30% by weight of the organic modification, preferably less than 20% by weight of the organic modification. The hectorite clay may comprise at least 1% by weight organic modification, at least 5% by weight organic modification or at least 10% by weight organic modification. Thus, the hectorite clay may comprise from 1 to 40% by weight organic modification, from 5 to 30% by weight organic modification, preferably from 10 to 20% by weight organic modification.
Typically, the hectorite clay comprises water. The hectorite clay may comprise from 1 to 30% by weight water, from 1 to 20% by weight water, preferably from 5 to 15% by weight water. Thus, the hectorite clay may comprise from 60 to 85% by weight clay material, from 5 to 30% by weight organic modification and from 1 to 20% by weight water. Preferably, the hectorite clay comprises from 70 to 80% clay material, from 10 to 20% by weight organic modification and from 5 to 15% by weight water. The content of clay material, organic modification and water may be determined using thermogravimetric-gas chromatography-mass spectrometry (TGA-GC-MS).
The percentages by weight may be determined using TGA-GC-MS and elemental analysis. For instance, TGA-GC-MS and elemental analysis may show the presence of carbon indicating the presence of the organic modification. Typically, when subjected to TGA- GC-MS and elemental analysis, the hectorite clay comprises from 0.5% to 30% by weight carbon, for instance from 1 to 25% by weight carbon, from 5 to 20% by weight carbon, preferably from 5 to 15% by weight carbon. Typically, when subjected to TGA-GC-MS and elemental analysis, the hectorite clay comprises from 0.5% to 30% by weight carbon, from 1% to 10% by weight hydrogen, up to 5% by weight nitrogen, from 1% to 20% by weight magnesium, from 10% to 40% by weight silicon, from 0.01% to 1% by weight calcium, from 0.1% to 10% by weight sodium and from 0.01% to 1% by weight lithium. For instance, when subjected to TGA-GC-MS and elemental analysis, the hectorite clay may comprise from 5% to 15% by weight carbon, from 1% to 5% by weight hydrogen, from 0.1 to 2% by weight nitrogen, from 5% to 15% by weight magnesium, from 15% to 30% by weight silicon, from 0. 1% to 0.5% by weight calcium, from 0.5% to 5% by weight sodium and from 0.05% to 0.5% by weight lithium.
Preferably the hectorite clay is Laponite ™ EP from BYK. Thus, the composition preferably comprises a bentonite clay and Laponite ™ EP. The bentonite clay may be Bentopharm™ supplied by Wilfrid Smith Ltd, for instance Bentopharm™ B20 grade.
Thus, the composition may comprise Bentopharm™ and Laponite ™ EP.
Agrochemical formulation
The invention also provides an agrochemical formulation comprising
(a) a hectorite clay which comprises an organic modification, and
(b) one or more active ingredients, wherein at least one of the active ingredients is an agrochemical.
Typically, the hectorite clay comprising an organic modification is the only thickening agent present in the agrochemical formulation. Thus typically, only one clay is present in the agrochemical formulation (namely the hectorite clay comprising an organic modification).
Typically, the agrochemical formulation is a non-Newtonian fluid. For instance, the viscosity of the agrochemical formulation usually decreases upon application of a force. Thus, typically, the agrochemical formulation is a shear-thinning fluid. The agrochemical formulation may be thixotropic. Thixotropic materials display time-dependent shear thinning behaviour. For instance, thixotropic materials take a finite time to attain equilibrium viscosity when introduced to a change in shear rate.
The hectorite clay may be any hectorite clay as described herein. Typically, the hectorite clay is a synthetic hectorite clay. Thus, typically the composition comprises a synthetic hectorite clay comprising a hydrophilic organic modification.
The organic modification may be a bulk modification or a surface modification. Alternatively the organic modification may be present in both the bulk and on the surface of the clay material.
Suitable hydrophilic organic modifications include organic compounds comprising carbonyl groups, for instance organic compounds comprising acetate groups. For instance, the hydrophilic organic modifications may comprise an anionic polymer. The hydrophilic organic modification may comprise a surfactant. The hydrophilic organic modification may comprise an organic compound comprising a carboxylate anion, for instance a metal carboxylate.
Typically, the hectorite clay comprises less than 95% by weight clay material, for instance less than 90% by weight clay material, less than 85% by weight clay material or less than 80% by weight clay material. Typically, the hectorite clay comprises at least 50% by weight clay material, at least 60% by weight clay material preferably at least 70% by weight clay material. Thus, the hectorite clay typically comprises from 50 to 95% by weight clay material, or from 60 to 85% by weight clay material, preferably from 70 to 80% clay material. Typically, the hectorite clay comprises less than 40% by weight of the organic modification, less than 30% by weight of the organic modification, preferably less than 20% by weight of the organic modification. The hectorite clay may comprise at least 1% by weight organic modification, at least 5% by weight organic modification or at least 10% by weight organic modification. Thus, the hectorite clay may comprise from 1 to 40% by weight organic modification, from 5 to 30% by weight organic modification, preferably from 10 to 20% by weight organic modification.
Typically, the hectorite clay comprises water. The hectorite clay may comprise from 1 to 30% by weight water, from 1 to 20% by weight water, preferably from 5 to 15% by weight water. Thus, the hectorite clay may comprise from 60 to 85% by weight clay material, from 5 to 30% by weight organic modification and from 1 to 20% by weight water. Preferably, the hectorite clay comprises from 70 to 80% clay material, from 10 to 20% by weight organic modification and from 5 to 15% by weight water.
The content of clay material, organic modification and water may be determined using thermogravimetric-gas chromatography-mass spectrometry (TGA-GC-MS).
The percentages by weight may be determined using TGA-GC-MS and elemental analysis. For instance, TGA-GC-MS and elemental analysis may show the presence of carbon indicating the presence of the organic modification. Typically, when subjected to TGA- GC-MS and elemental analysis, the hectorite clay comprises from 0.5% to 30% by weight carbon, for instance from 1 to 25% by weight carbon, from 5 to 20% by weight carbon, preferably from 5 to 15% by weight carbon. Typically, when subjected to TGA-GC-MS and elemental analysis, the hectorite clay comprises from 0.5% to 30% by weight carbon, from 1% to 10% by weight hydrogen, up to 5% by weight nitrogen, from 1% to 20% by weight magnesium, from 10% to 40% by weight silicon, from 0.01% to 1% by weight calcium, from 0.1% to 10% by weight sodium and from 0.01% to 1% by weight lithium. For instance, when subjected to TGA-GC-MS and elemental analysis, the hectorite clay may comprise from 5% to 15% by weight carbon, from 1% to 5% by weight hydrogen, from 0.1 to 2% by weight nitrogen, from 5% to 15% by weight magnesium, from 15% to 30% by weight silicon, from 0. 1% to 0.5% by weight calcium, from 0.5% to 5% by weight sodium and from 0.05% to 0.5% by weight lithium. Preferably the hectorite clay is Laponite™ EP from BYK. Thus, the agrochemical formulation preferably comprises Laponite™ EP.
Typically, the hectorite clay is present in an amount of from 0.01 to 5% by weight of the agrochemical formulation. For instance, the hectorite clay may be present in an amount of from 0.05% to 2% by weight of the agrochemical formulation, preferably between 0.2% to 1.5% by weight of the agrochemical formulation.
Typically, the agrochemical formulation comprises a liquid phase. The liquid phase typically comprises water. Thus, the liquid phase is typically aqueous. Further ingredients, such as surfactants, salts, anti-freeze agents and dispersants may be dissolved in the liquid phase.
Typically, at least one of the active ingredients in the agrochemical formulation is a salt of an agrochemical. The inventors have surprisingly discovered that, in the presence of a salt, the hectorite clay comprising an organic modification is able to impart the desired rheological properties in terms of gel formulation and shear-thinning. Thus, the agrochemical formulation of the present invention is particularly well-suited for formulations comprising soluble salts of agrochemicals, for instance, herbicide, pesticide or fungicide salts or the salt of a plant growth regulator. Examples of such salts include glyphosate as the potassium salt, dicamba as the sodium salt, 2,4-D as the dimethylamine salt, glufosinate as the ammonium salt and halide salts of mepiquat. The agrochemical may be a salt of a plant growth regulator, for instance a plant growth regulator which is a mepiquat halide, typically mepiquat chloride.
The agrochemical formulation may comprise multiple active ingredients which are salts of agrochemicals. For instance, the agrochemical formulation may comprise at least two active ingredients which are salts of agrochemicals, at least three active ingredients which are salts of agrochemicals or at least four active ingredients which are salts of agrochemicals. The salts of agrochemicals may be selected from herbicide, pesticide or fungicide salts and/or salts of a plant growth regulator. The salts of agrochemicals may be selected from glyphosate as the potassium salt, dicamba as the sodium salt, 2,4-D as the dimethylamine salt, glufosinate as the ammonium salt and halide salts of mepiquat. For instance, the agrochemical may be a salt of a plant growth regulator, for instance a plant growth regulator which is a mepiquat halide, typically mepiquat chloride. Other salts include salts of dicamba and salts of glyphosate.
Typically, the agrochemical formulation comprises a synthetic hectorite clay which comprises a hydrophilic organic modification and at least one salt of an agrochemical selected from herbicide, pesticide or fungicide salts and/or salts of a plant growth regulator. For instance, the agrochemical formulation may comprise Laponite™ EP and at least one salt of an agrochemical selected from herbicide, pesticide or fungicide salts and/or salts of a plant growth regulator. The agrochemical formulation may comprise Laponite™ EP and at least a mepiquat halide, typically mepiquat chloride. The agrochemical formulation may comprise Laponite™ EP and the salt of an herbicide, for instance a dicamba salt or a glyphosate salt.
Typically, the agrochemical is present in the agrochemical formulation in an amount from 10 to 70% by weight, for instance from 20 to 60 % by weight, preferably from 30 to 50% by weight.
The agrochemical formulation may further comprise one or more agrochemicals which are dispersed in the agrochemical formulation or are present in the agrochemical formulation in emulsified form. Thus, at least one of the agrochemicals may be only partially water soluble or insoluble in water. When at least one of the agrochemicals is present in the agrochemical formulation in emulsified form, the agrochemical is typically emulsified in an oil, for instance an alkylnaphthalene solvent such as Solvesso™ 200. Typically, when at least one of the agrochemicals is present in the agrochemical formulation in emulsified form the agrochemical formulation further comprises one or more surfactants, typically anionic or non-ionic surfactants, as described herein. When at least one of the active ingredients is present in the agrochemical formulation in emulsified form the particle gel may further comprise one or more anti-foaming agents. Suitable anti-foaming agents include Dow Corning ™ antifoam MSA and Dow Coming ™ antifoam 1520. Thus, the agrochemical formulation may further comprise one or more agrochemicals which are dispersed in the agrochemical formulation or are present in the agrochemical formulation in emulsified form selected from pesticides, fungicides, insecticides, herbicides and plant growth regulators. For instance, the agrochemical formulation may comprise a fungicide which is azoxystrobin.
The agrochemical formulation may comprise a surfactant as described herein. The agrochemical formulation may comprise a dispersant as described herein. The agrochemical formulation may comprise a salt as described herein. The agrochemical formulation may comprise a pH modifying agent as described herein. The agrochemical formulation may comprise an anti-freezing agent as described herein.
For instance, the agrochemical formulation may comprise two or more, for instance three or more or four or more selected from the group consisting of a surfactant as described herein, a dispersant as described herein, a salt as described herein, a pH modifying agent as described herein and an anti-freezing agent as described herein. The agrochemical formulation may comprise a surfactant as described herein, a dispersant as described herein, a salt as described herein, a pH modifying agent as described herein and an anti freezing agent as described herein.
Use
The invention also provides the use of a particle gel as described herein, a composition as described herein, or an agrochemical formulation as described herein, as a plant protection product. A plant protection product maybe any product designed to protect plants of interests from pests (e g. insects, fungal diseases) or from competition for resources from other plants. Thus, the plant protection product typically comprises at least one active ingredient that protects plants. Typically, the plant protection product comprises at least one of a fungicide as described herein, an insecticide as described herein, an herbicide as described herein or a plant growth regulator as described herein.
For instance, the particle gel as described herein, composition as described herein, or agrochemical formulation as described herein, may be used as a fungicide. The particle gel as described herein, composition as described herein, or agrochemical formulation as described herein, may be used as an insecticide. The particle gel as described herein, composition as described herein, or agrochemical formulation as described herein, may be used as an herbicide. The particle gel as described herein, composition as described herein, or agrochemical formulation as described herein, may be used to regulate plant growth. The particle gel as described herein, composition as described herein, or agrochemical formulation as described herein, is typically used to protect a crop of interest, for instance on a farm. For instance, the particle gel as described herein, composition as described herein, or agrochemical formulation as described herein, may be used to protect a maize crop or a cereal crop.
EXAMPLES
Example 1: Formulations of azoxystrobin as Suspension Concentrate (SC) #1 comprising anionic dispersant in the millbase
Laponite™ EP 2% gel was prepared as followed: 2g of Laponite™ EP put into 50g of water then addition of water up to lOOg. Then high shear applied with a high shear mixer from IKA (ULTRA-TURRAX™ digital T25 with impeller S25N-18G) at about 17,000 rpm for about 10 minutes until dissolution. Then centrifugation at 1000 rpm for 5mins was used to remove air bubbles. Bentopharm™ B20 10% gel was prepared as follows: 90g of water to which lOg of
Bentopharm™ B20 are added while high shear mixed. Slow increase of the speed of the high shear mixer from IKA (ULTRA-TURRAX™ digital T25 with impeller S25N-18G) was applied during addition of Bentopharm™ B20 in order to create and maintain a vortex. Bentopharm formula: Bentonite = mainly sodium montmorillonite
Example 1 : ingredients were then mixed in the following order according to the following recipes:
Figure imgf000036_0001
1. Water 2. Millbase #1 (comprising an anionic dispersant, 6% by mass Morwet™ D425, and an active ingredient, the fungicide Azoxystrobin at 50% by mass dispersed in water)
3. Laponite™ EP 2% (w/w) gel 4. Bentopharm™ 10% (w/w) gel
5. Propylene glycol
Figure imgf000037_0003
Stir until complete homogenisation with magnetic stirrer.
Preparation of the comparative example (control sample) with anionic dispersant Ingredients were then mixed in the following order according to the following recipes:
Figure imgf000037_0002
1 Millbase #1 (as described above)
2. Xanthan 2% (w/w) gel
3. Bentopharm™ 10% (w/w) gel 4. Propylene glycol
5. Water
Figure imgf000037_0004
Stir until complete homogenisation with magnetic stirrer.
Rheological test protocol Oscillations and flow ramp test Rheological tests were performed on a stress controlled rheometer AR-G2 from TA
Instruments using a concentric cylinder (geometry used in the rheometer) with a DIN rotor. Conditioning at 25°C; pre-shear at 100 s-1 for 60s; equilibration for 1200s Strain Oscillation at 25°C; from 10-4 to 10; at 1 Hz; conditioning cycles: 3; Sampling cycles: 2 Conditioning at 25°C; pre-shear at 600 s-1 for 60s; equilibration for 600s Ramp up at 25°C; From 0 to 600 s-1 for 900s; sampling interval: 1 s/pt Ramp down at 25°C; from 600 to 0 s-1 for 900s; sampling interval: 1 s/pt from the flow ramp up calculate flow properties, fit with Casson model:
Figure imgf000037_0005
Figure imgf000037_0001
Vo = tfc2
Rheological test protocol Frequency oscillations test Conditioning at 25°C ; pre-shear at 100 s-1 for 60s; equilibration for 1200s Frequency Oscillation at 25°C; from 102 to 100 Hz; at 1 Pa or O.lPa (Control with
Figure imgf000038_0003
anionic dispersant) or at a stress within the LVR; conditioning cycles: 15; sampling cycles: 10 Results initial rheological tests (flow ramp and oscillation tests)
Flow ramp results - two tests (called 1st test and 2nd test) were carried out on two different samples both made the same way (to determine the reproducibility of the results). A control sample of Azoxystrobin SC #1 was used for comparison. The experiment on the second test was performed seven days after making the sample to check whether the rheological properties altered over time. Results for the yield stress (σc) and infinite viscosity (pinfinit) are shown below in Table 1 and Figure 1. Results for the viscosity at a shear rate of 10 s-1 and 20s-1 are shown in Table 2 and Figure 2.
Table 1
Figure imgf000038_0001
Table 2
Figure imgf000038_0002
Figure imgf000039_0001
Strain oscillation results are shown in Figure 3. Table 3 shows the results for the elastic modulus (G’), the loss modulus (G”) and the critical strain (“/critic). Table 3
Figure imgf000039_0002
Figure 4 shows the frequency oscillation results for the first samples only. All samples showed the same behaviour with time showing that the gels were stable for a long time. Model established using the mode-coupling theory (MCT) (see Lidon, Pierre, Louis Villa, and Sebastien Manneville. "Power-law creep and residual stresses in a carbopol gel." Rheologica Acta 56.3 (2017): 307-323):
G’(w)=constant at low frequency
G”(w)=a*wn where n correspond to the Andrade exponent between 0.2 and 0.7 Results for the fitting of G” are shown in Table 4: Table 4
Figure imgf000039_0003
Figure imgf000040_0001
Industrial test results
The pourability test was performed as follows: a 25mL cylinder was weighed empty (W 1), - the gel was poured into the cylinder and the weight was recorded (W2)
- the weight of the sample was calculated as W3=W2-W 1.
- the cylinder containing the gel was allowed to stand at room temperature for 30 minutes.
- the cylinder was emptied back into the original sample bottle by tilting the cylinder at 45° for 60s and holding it vertically for 60s afterwards.
- the weight of the cylinder W4 was taken.
- the weight of the residues was obtained: W5=W4-W1.
- the percentage residue was calculated as follows: (W5/W3)*100. Dilution was performed by adding lmL of sample into a lOOmL cylinder containing 100 mL of deionised water. Inversions were performed afterwards until dispersion of the residues. The number of inversions needed to achieve a full dissolution leads to a grade A, B, C, D. A being the best. Pourability and dilution results are shown in Table 5. In both cases the results were satisfactory and suitable for industrial application.
Table 5
Figure imgf000040_0002
Storage test results of rheological tests after four weeks storage at 40°C The same rheological tests as described above were performed on the samples after four weeks storage in non-ideal conditions (at 40°C). Table 6 and Figure 5 show the flow ramp results. Table 7 and Figure 6 show the viscoelasticity results.
Table 6
Figure imgf000041_0001
Table 7
Figure imgf000041_0002
Storage test results of industrial tests after four weeks storage at 40°C No phase separation was observed for either sample after four weeks storage at 40°C. The pourability and dilution tests results, assessed according the method described above, are provided below in Table 8. Table 8
Figure imgf000042_0001
Example 2: Formulation of azoxystrobin Suspension Concentrate (SC) #2 using nonionic dispersant in the millbase
Recipe
Figure imgf000042_0002
Ingredients were added in the following order:
1 Water
2. Millbase (comprising a non-ionic dispersant, 6% by mass Atlox™ 4913, and an active ingredient, a fungicide Azoxystrobin at 50% by mass dispersed in water) 3. Laponite™ EP 2% (w/w) gel
4. Bentopharm™ 10% (w/w) gel
5. Propylene glycol
Figure imgf000042_0003
Stir until complete homogenisation with magnetic stirrer.
Preparation of the comparative example (control sample) with non-ionic dispersant Example 2: ingredients were then mixed in the following order according to the following recipes:
Figure imgf000043_0001
1 Millbase (as described above)
2. Xanthan 2% (w/w) gel
3. Bentopharm™ 10% (w/w) gel 4. Propylene glycol
5. Water Stir until complete homogenisation with magnetic stirrer.
Figure imgf000043_0004
Results rheological tests (flow ramp and oscillation tests) Rheological measurements (flow ramp and oscillation testing) were performed as described above. Results for the yield stress (σc) and infinite viscosity are shown
Figure imgf000043_0005
below in Table 9 and Figure 7. Results for the viscosity at a shear rate of 10 s-1 and 20s-1 are shown in Table 10 and Figure 8.
Table 9
Figure imgf000043_0002
Table 10
Figure imgf000043_0003
Strain oscillation results are shown in Figure 9. Table 11 shows the results for the elastic modulus (G’), the loss modulus (G”) and the critical strain (“/critic).
Table 11
Figure imgf000044_0001
Figure 10 shows the frequency oscillation results for the first samples only. All samples showed the same behaviour with time showing that the gels were stable for a long time. Model established using the mode-coupling theory (MCT) as described above. Results for the fitting of G” are shown in Table 12.
Table 12
Figure imgf000044_0002
Industrial test results
Pourability and dilution were assessed according to the method described above. The results are shown in Table 13. Good pourability was observed and the results for the dilution test were satisfactory.
Table 13
Figure imgf000044_0003
Figure imgf000045_0001
Storage test results of rheological tests after four weeks storage at 40°C The same rheological tests as described above were performed on the sample after four weeks storage in non-ideal conditions (at 40°C). Table 14 and Figure 11 show the flow ramp results. Table 15 and Figure 12 show the viscoelasticity results.
Table 14
Figure imgf000045_0002
Table 15
Figure imgf000045_0003
The results show very little change in rheological properties of the sample after four weeks storage at 40°C.
Storage test results of industrial tests after four weeks storage at 40°C
Dilution test results were satisfactory for the sample after four weeks storage at 40°C.
Example 3: comparison between Laponite™ EP (with organic modification) 2% w/w and Laponite™ RD (without organic modification) 5% w/w
Laponite™ EP 2% gel was prepared as described above. Laponite™ RD 5% gel was prepared as followed: 5g of Laponite™ RD put into 50g of water then addition of water up to lOOg. Then high shear with a high shear mixer from IKA (ULTRA-TURRAX™ digital T25 with impeller S25N-18G) for about 10 minutes until dissolution. Then centrifugation to remove air bubble at 1000 rpm for 5 minutes.
Rheological protocol for evaluating aging of the gel (using a DIN rotor geometry (geometry fitted to the rheometer) or a Vane rotor): Conditioning at 25°C; pre-shear at 100 s-1 for 60s First time Oscillation at 25°C; during 440000s (5 days) or stopped before; at lHz; at 1 Pa or within the LVR; conditioning cycles: 20; sampling cycles: 10 Conditioning at 25°C; pre-shear at 100 s-1 for 60s Second time Oscillation at 25°C; during 440000s (5days) or stopped before; at
Figure imgf000046_0001
1Hz; at a 1 Pa or within the LVR; conditioning cycles: 20; sampling cycles: 10
The results of the rheological tests looking at the aging are shown in Figure 13. Once the gel is formed no difference on the aging => both clay seems to swell (as shown by the beginning of the curve). Same process for gel “recovery” after shearing it so after getting destroyed.
However, the gelation concentration is not the same: 2% of Laponite™ EP is enough to have a strong gel whereas it is not with Laponite™ RD.
Examples 4-6: comparison between Laponite™ EP - Bentopharm™ and Laponite™ RD -Bentopharm™ - effect of pH, salt (MgCh) and surfactant (TWEEN20)
Systems used:
Laponite™ EP 5g/L + Bentopharm™ 20g/L
Laponite™ RD 15g/L + Bentopharm™ 20g/L (Note - no gel could be formed with Laponite™ RD 5g/L + Bentopharm™ 20g/L)
Ingredients were added in the following order:
1. Water
2. Laponite™ EP 2% (w/w) gel/Laponite™ RD 5% (w/w) gel
3. Bentopharm™ 10% (w/w) gel
4. pH adjustment/MgCl2 addition/TWEEN20 Stir until complete homogenisation with a high shear mixer IKA (ULTRA-
Figure imgf000047_0003
TURRAX™ digital T25 with impeller S25N-18G).
Rheological protocol (using a DIN rotor geometry (geometry fitted to the rheometer) or a Vane rotor (for the first 3 parts)): Conditioning at 25°C; pre-shear at 100 s-1 for 60s; equilibration for 1200s Time Oscillation at 25°C; during lh30 or 3 hours; at lHz; at a fixed stress (within the LVR); conditioning cycles: 20; sampling cycles: 10 Strain Oscillation at 25°C; from 104 to 10; at 1 Hz; conditioning cycles: 10; sampling cycles: 10 Conditioning at 25°C; pre-shear at 600 s 1 for 60s; equilibration for 600s; Ramp up at 25°C; from 0 to 600 s 1 for 900s; sampling interval: 1 s/pt Ramp down at 25°C; from 600 to 0 s 1 for 900s; sampling interval: 1 s/pt Flow properties: fitting of the flow ramp up with Casson model:
Figure imgf000047_0004
Figure imgf000047_0001
Example 4: comparison between Laponite™ EP - Bentopharm™ and Laponite™ RD -Bentopharm™ - effect of pH
Results with Laponite™ EP
Strain oscillation results are shown in Figure 14 for Laponite™ EP 5g/L + Bentopharm™ 20g/L (without pH modification) and for Laponite™ EP 5g/L + Bentopharm™ 20g/L (at pH 4). Table 16 shows the results for the elastic modulus (G’), the loss modulus (G”) and the critical strain (ycritic). The initial (unmodified) pH of Laponite™ EP 5g/L + Bentopharm™ 20g/L is 8.96.
Table 16
Figure imgf000047_0002
The results show that the gel is strengthened at pH 4, possibly due to the impact of the electrostatic effect and the interlayer space between platelets being reduced. Figure 15 and Table 17 show the results of the flow ramp testing on Laponite™ EP 5g/L + Bentopharm™ 20g/L (without pH modification) compared to Laponite™ EP 5g/L +
Bentopharm™ 20g/L (at pH 4).
Table 17
Figure imgf000048_0001
Results with Laponite ™ RD
Strain oscillation results are shown in Figure 16 for Laponite™ RD 15g/L + Bentopharm™ 20g/L (without pH modification) and for Laponite™ RD 15g/L + Bentopharm™ 20g/L (at pH 4). Table 18 shows the results for the elastic modulus (G’), the loss modulus (G”) and the critical strain (ycritic). The initial (unmodified) pH of Laponite™ EP 5g/L + Bentopharm™ 20g/L is 9.67.
Table 18
Figure imgf000048_0002
Figure 17 and Table 19 show the results of the flow ramp testing on Laponite™ RD 15g/L + Bentopharm™ 20g/L (without pH modification) compared to Laponite™ RD 15g/L +
Bentopharm™ 20g/L (at pH 4).
Table 19
Figure imgf000048_0003
Example 5: comparison between Laponite™ EP - Bentopharm™ and Laponite™ RD -Bentopharm™ - effect of a salt (MgCh)
Results with Laponite™ EP
Strain oscillation results are shown in Figure 18 for Laponite™ EP 5g/L + Bentopharm™ 20g/L with various concentrations ofMgCl2. Table 20 shows the results for the elastic modulus (G’), the loss modulus (G”) and the critical strain (ycritic).
Table 20
Figure imgf000049_0001
Figure 19 shows the results of the flow ramp testing for Laponite™ EP 5g/L + Bentopharm™ 20g/L with various concentrations of MgCh. The gel is strengthened with MgCh, possibly because MgCh is very hygroscopic and its addition decreases the osmotic pressure in the bulk with water leaving the network to go to the bulk -> contraction of the electrical double layer. Hence the platelets get closer to each other which increases the strength of the network Results w ith Laponite™ RD
Strain oscillation results are shown in Figure 20 for Laponite™ RD 15g/L + Bentopharm™ 20g/L with various concentrations of MgCh. Table 21 shows the results for the elastic modulus (G’), the loss modulus (G”) and the critical strain (“/critic).
Table 21
Figure imgf000049_0002
Figure 21 shows the results of the flow ramp testing for Laponite™ RD 15g/L + Bentopharm™ 20g/L with various concentrations of MgCh.
The gel is also strengthened with MgCh, the same hypothesis described in the case of Laponite™ EP 5g/L + Bentopharm™ 20g/L can be applied for Laponite™ RD 15g/L + Bentopharm™ 20g/L. Example 6: comparison between Laponite™ EP - Bentopharm™ and Laponite™ RD -Bentopharm™ - effect of a surfactant (Tween 20)
Results with Laponite™ EP Strain oscillation results are shown in Figure 22 for Laponite™ EP 5g/L + Bentopharm™ 20g/L (without surfactant) and for Laponite™ EP 5g/L + Bentopharm™ 20g/L (with various concentrations of surfactant - Tween 20). Table 22 shows the results for the elastic modulus (G’), the loss modulus (G”) and the critical strain (ycritic).
Table 22
Figure imgf000050_0001
Figure 23 and Table 23 show the results of the flow ramp testing Laponite™ EP 5g/L + Bentopharm™ 20g/L (without surfactant) and for Laponite™ EP 5g/L + Bentopharm™ 20g/L (with various concentrations of surfactant - Tween 20).
Table 23
Figure imgf000050_0002
The gel comprising Laponite™ EP is strengthened with Tween 20. An increase in yield stress and viscosity is observed with increasing concentration of Tween 20. The results obtained with 20% (w/w) may be due to the formation of micelles or a highly ordered system in the bulk increasing the viscosity of the solution whereas the critical micelle concentration may not have been reached at a concentration of 1 or 10%. With Laponite™ EP, Tween 20 does not destroy the gel structure, whereas it does for Laponite™ RD (see results below).
Results with Laponite™ RD Strain oscillation results are shown in Figure 24 for Laponite™ RD 15g/L + Bentopharm™ 20g/L (without surfactant) and for Laponite™ RD 15g/L + Bentopharm™ 20g/L (with various concentrations of surfactant - Tween 20). Table 24 shows the results for the elastic modulus (G’), the loss modulus (G”) and the critical strain (ycritic).
Table 24
Figure imgf000051_0001
Figure 25 and Table 25 show the results of the flow ramp testing for Laponite™ RD 15g/L + Bentopharm™ 20g/L (without surfactant) and for Laponite™ RD 15g/L + Bentopharm™ 20g/L (with various concentrations of surfactant - Tween 20).
Table 25
Figure imgf000051_0002
The gel comprising Laponite™ RD is weakened when Tween 20 is added.
Example 7: comparison of different azoxystrobin SC using Laponite™ EP as gelling agent with the anionic dispersant containing millbase
Preparation of the Solution Concentrates
The solutions were prepared according to the following procedure to reach the concentration given below:
Figure imgf000051_0003
Figure imgf000052_0001
1. Water
2. Millbase #1 (comprising an anionic dispersant, 6% by mass Morwet™ D425, and an active ingredient, a fungicide Azoxystrobin at 50% by mass dispersed in water)
3. Laponite™ EP 2% (w/w) gel
4. Bentopharm™ 10% (w/w) gel if required 5 Propylene glycol
^ Stir until complete homogenisation with magnetic stirrer.
The mix of water, Millbase #1 and propylene glycol is referred to as anionic suspension in this example and in Figure 26 and Figure 27.
Strain oscillation results are shown in Figure 26 for the use of Laponite™ EP 5g/L, Laponite™ EP lOg/L or Laponite™ EP 5g/L + Bentopharm™ 20g/L as gelling agent. Table 26 shows the results for the elastic modulus (G’), the loss modulus (G”) and the critical strain (ycritic).
Table 26
Figure imgf000052_0002
The addition of 20g/L of Bentopharm™ to 5g/L of Laponite™ EP strengthen the gel more than doubling the Laponite™ concentration to lOg/L without reducing too much the length of the LVR as shown by the values of
Figure imgf000052_0003
which is higher in the case of Laponite™ 5g/L + Bentopharm™ 20g/L than Laponite™ EP 10g/L.
Figure 27 and Table 27 show the results of the flow ramp testing for Laponite™ EP 5g/L, Laponite™ EP lOg/L or Laponite™ EP 5g/L + Bentopharm™ 20g/L.
Table 27
Figure imgf000052_0004
Figure imgf000053_0001
The increase in concentration of Laponite™ EP to lOg/L or the addition of 20g/L of Bentopharm™ to 5g/L of Laponite™ EP leads to a higher yield stress and viscosity. However, the former one may feature a slightly higher viscosity and yield stress than the latter one.
Example 8: effect of Laponite™ EP and Laponite™ RD upon the gelling of a range of electrolyte solutions including agrochemicals
Laponite™ EP pre-gels were combined with a range of electrolyte (salt) solutions by mixing. The following salt solutions were investigated:
• Mepiquat (MPQ) as the chloride (Cl) salt
• Glyphosate as the potassium (K) salt
• Dicamba as the amino-propylmorpholine (APM) salt
• Ammonium sulphate (AMS)
Preparation method: Laponite™ EP and Laponite™ RD as 2% by mass aqueous gels were both prepared as explained in Examples 1 and 2. A Laponite™ EP gel was also made at 4.5% by mass for Sample 3 specifically. Mepiquat chloride technical powder material (98.3% chemical purity) was weighed into a glass jar and then Laponite™ gel added followed by mild agitation by rolling within the glass jar for 1 hour.
Sample A :
• Mepiquat chloride (98.3% purity) 6.93 grams
• Deionised water 9.02 grams
Sample B :
• Mepiquat chloride (98.3% purity) 6.91 grams
• Laponite™ EP 2% gel 9.03 grams
• Deionised water nil
Sample J : • Mepi quat chi ori de (98.3 % purity) 6.88 grams
• Laponite™ RD 2% gel 9.05 grams
• Deionised water nil Sample X:
• Laponite™ EP 2% gel 14.35 grams
• Deionised water nil 16.05 grams
Table 28
Figure imgf000054_0001
Table 29
Figure imgf000054_0002
Taken together this data shows that there is a surprising synergistic interaction between Mepiquat chloride salt solution and the Laponite™ EP synthetic clay. There is also a clear distinction between the effect of Laponite™ EP and Laponite™ RD in terms of the gelling effect in the salt solution.
It should be noted that bentonite clay (Bentopharm™ B20) was not readily dispersible in the Mepiquat chloride salt solution. There was apparently an unfavourable interaction that appeared to render the bentonite clay as hydrophobic.
Further examples using different agrochemical salt solutions
• Glyphosate as the potassium (K) salt
• Dicamba as the amino-propylmorpholine (APM) salt
• Ammonium sulphate (AMS)
Sample U :
• Potassium glyphosate (as 48.3% glyphosate acid equivalent AE purity) 6.97 grams
• Laponite™ EP 2% gel 9.00 grams
• Deionised water nil
Sample V :
• Potassium glyphosate (as 48.3% glyphosate acid equivalent AE purity) 6.99 grams
• Laponite™ RD 2% gel 9.01 grams
• Deionised water nil
Sample Y :
• APM dicamba (as 488 g/1 dicamba acid equivalent AE purity) 7.01 grams
• Laponite™ EP 2% gel 9.01 grams
• Deionised water nil
Sample Z :
• APM dicamba (as 488 g/1 dicamba acid equivalent AE purity) 6.99 grams
• Laponite™ RD 2% gel 9.02 grams
• Deionised water nil
Sample 1 • Ammonium sulphate (as 300 g/1 AMS purity) 7.00 grams
• Laponite™ EP 2% gel 9.01 grams
• Deionised water nil Sample 2 :
• Ammonium sulphate (as 300 g/1 AMS purity) 6.98 grams
• Laponite™ EP 4.5% gel 9.01 grams
• Deionised water nil Sample 3 :
• Ammonium sulphate (as 300 g/1 AMS purity) 7.01 grams
• Laponite™ RD 2% gel 9.00 grams
• Deionised water nil Table 30
Figure imgf000056_0001
Table 31
Figure imgf000057_0001
This data reveals the unexpected result that a wide range of salts across different ionic strengths, varying anions and cations and different pH values can be efficiently gelled using Laponite™ EP whereas Laponite ™ RD by comparison is much less effective. This use of Laponite™ EP within agrochemical formulations would also be applicable to fertilizer-tolerant dispersions whereby the dilution step was of the dispersed agrochemical product into fertilizer solution rather than water. Fertilizer solutions such as urea- ammonium-nitrate (UAN) are commonly used in North America as spray fluids, for example.
Example 9: comparison of different SC containing Azoxystrobin with anionic dispersant using Laponite™ EP as gelling agent. Preparation of the Solution Concentrates
The solutions were prepared according to the following procedure to reach the concentration given below:
Figure imgf000058_0001
1. Water
2. Millbase #1 as supplied by Syngenta Limited comprising an anionic dispersant, 6% by mass Morwet™ D425, and an active ingredient, a fungicide Azoxystrobin at 50% by mass dispersed in water 3. Laponite™ EP 2% (w/w) gel prepared as described example 1
4. Bentopharm™ 10% (w/w) gel prepared as described p. 33, if required
5. Propylene glycol
^ Stir until complete homogenisation with magnetic stirrer.
The mix of water, Millbase #1 and propylene glycol is referred to as anionic suspension in this example and in Figure 28 and Figure 29.
Results
Strain oscillation results are shown in Figure 28 for the use of Laponite™ EP 5g/L, Laponite™ EP lOg/L, Bentopharm™ 20g/L, Bentopharm™ 40g/L and Laponite™ EP 5g/L + Bentopharm™ 20g/L as gelling agent. Table 32 shows the results for the elastic modulus (G’), the loss modulus (G”) and the critical strain (ycritic). Note that the values displayed in Table 30 for Laponite™ EP 5g/L, Laponite™ EP lOg/L and Laponite™ EP 5g/L + Bentopharm™ 20g/L were obtained based on the mean of two repetitions. Table 32
Figure imgf000059_0001
The addition of 20g/L of Bentopharm™ to 5g/L of Laponite™ EP strengthens the gel, Doubling the Laponite™ concentration to lOg/L does not significantly change the length of the LVR as shown by the values of
Figure imgf000059_0003
which is about the same in the case of Laponite™ 5g/L + Bentopharm™ 20g/L as Laponite™ EP lOg/L. 20 g/L of Bentopharm™ does not comply with the requirement of having G’ above 20 Pa which may lead to some sedimentation of particles happening at rest. However, doubling the Bentopharm™ concentration to 40g/L leads to a too strong gel.
Figure 29 and Table 33 show the results of the flow ramp test for Laponite™ EP 5g/L, Laponite™ EP lOg/L, Bentopharm 20g/L, Bentopharm 40g/L and Laponite™ EP 5g/L + Bentopharm™ 20g/L. Note that the values displayed in Table 33 for Laponite™ EP 5g/L, Laponite™ EP lOg/L and Laponite™ EP 5g/L + Bentopharm™ 20g/L were obtained based on the mean of two repetitions.
Table 33
Figure imgf000059_0002
The increase in concentration of Laponite™ EP to lOg/L or the addition of 20g/L of Bentopharm™ to 5g/L of Laponite™ EP leads to a higher yield stress and viscosity. However, a gel containing Laponite™ EP at lOg/L may feature a slightly higher viscosity and yield stress than the gel with 20g/L of Bentopharm™ and 5g/L of Laponite™ EP. Using Bentopharm™ alone at 20g/L as a thickening agent is not enough to guarantee a yield stress which is high enough to prevent sedimentation of particles. Increasing the concentration of Bentopharm™ to 40g/L allows an increase in the yield stress but not as much as the addition of 5g/L of Laponite™EP. In addition, the very high elastic modulus (G’) of the gel formed by the anionic suspension + Bentopharm™40g/L prevents its use.
Example 10: study of the combination of Laponite™ EP + Ben top harm with mesotrione acid as active ingredient (formulated as copper chelate)
Laponite™ EP 2% gel was prepared as previously described.
Bentopharm™ B20 10% gel was prepared as previously described.
Rhodopol™ 2% gel was prepared as follows: 2g of Rhodopol™ added to 50g of water then addition of water to lOOg. Then high shear mixing using an IKA high shear mixer (ULTRA- TURRAX™ digital T25 with impeller S25N-18G) at 19200 rpm for 6 minutes and 21 000 rpm for 5 minutes afterwards. Then centrifugation at 1000 rpm for 5 minutes to remove air bubbles. The foam formed at the top was removed with a spatula.
Attagel™ 10% gel was prepared as follows: lOg of Attagel™were added to 50g of water then addition of water to lOOg. Then high shear mixing using an IKA high shear mixer
(ULTRA- TURRAX™ digital T25 with impeller S25N-18G) at 14 000 rpm for 10 minutes.
Ingredients were then mixed in the following order according to the following recipes:
Figure imgf000060_0001
1. Water
2 Millbase #3 as supplied by Syngenta Limited comprising an active ingredient, the herbicide mesotrione acid formulated as a copper chelate* at 30% mesotrione acid equivalent by mass dispersed in water 3. Laponite™ EP 2% (w/w) gel or Rhodopol™ 2% (w/w) gel
4. Bentopharm™ 10% (w/w) gel or Attagel™ 10% (w/w) gel if required
5. Propylene glycol Magnetic or high shear mixing until complete homogenisation with high shear
Figure imgf000061_0002
mixer from IKA (ULTRA-TURRAX™ digital T25 with impeller S25N-18G)
*US 5912207 discloses that metal chelates of herbicidal cyclohexane-dione compounds such as “mesotrione acid” have been prepared - the examples show how the copper chelate of mestrione acid is prepared & stabilised. The pH of the solutions were measured using the pH meter Five easy plus from Mettler Toledo. The pH varied between 3 and 3.6.
Preparation of the comparative example (control sample) with Rhodopol™ (xanthan) : Ingredients were then mixed in the following order to reach the following concentration:
Figure imgf000061_0001
1. Water
2. Millbase #3 (as described above)
3. Rhodopol™ 2% (w/w) gel
4. Propylene glycol
Figure imgf000061_0003
High shear mixing until complete homogenisation with high shear mixer from IKA
(ULTRA-TURRAX™ digital T25 with impeller S25N-18G)
Rheological test protocol Oscillations and flow ramp test
The same rheological test protocol as described for example 1 above was performed. Results - initial rheological tests (flow ramp and oscillatory tests)
Figure 30 shows the stress versus strain rate curve and the viscosity versus strain rate for Laponite™ EP combined with Bentopharm™ as thickening agent against the control with Rhodopol™ (xanthan) only, for gel containing copper-mesotrione. Figure 31 shows stress versus strain rate curve and the viscosity versus strain rate for Laponite™ EP combined with Attagel™ as thickening agent against the control with Rhodopol™ (xanthan) only, for gel containing copper-mesotrione. Table 34 shows the Casson yield stress and the infinite viscosity obtained from the fit of the flow ramp up by a Casson model.
Table 34
Figure imgf000062_0001
Using Rhodopol™ on its own was not enough to get a yield stress. Again the synergistic effect of Bentopharm™ combined with Laponite™ EP was stronger than the one between Laponite™ EP and Attagel. The Laponite™ EP/Attagel combination only featured a suitable yield stress at the highest possible concentration of Laponite™ EP and Attagel™. On the other hand, different formulations containing Laponite™ EP and Bentopharm™ gave appropriate yield stress and infinite viscosity. For these formulations, all requirements regarding the viscosities at 10s 1 and 20s-1 were met.
Strain oscillation results are presented in Table 35 for all formulations. Figure 32 shows G’ obtained during the strain oscillations for Laponite™ EP combined with Bentopharm™ as thickening agent compared to the control sample with Rhodopol™ (xanthan) for gel containing copper-mesotrione. Figure 33 shows G’ during the strain oscillations for Laponite™ EP combined with Attagel™ as thickening agent compared to the control sample with Rhodopol™ (xanthan) for gel containing copper-mesotrione.
Table 35
Figure imgf000062_0002
Figure imgf000063_0001
No gel could be obtained using xanthan 2g/L on its own when using copper-mesotrione as active ingredient. A gel could be formed using a combination of Laponite™ EP and Bentopharm™ or Laponite™ EP and Attagel™. However, the synergistic effect was much higher when combining Laponite™ EP and Bentopharm™ than when combining Laponite™ EP and Attagel™. In fact, even though a weak gel was formed using Attagel™, this may not be strong enough to prevent the sedimentation of the active ingredient despite the highest possible concentration of Attagel™ and Laponite™ EP being used. Combining Laponite™ EP and Bentopharm™ provides gels with different strengths depending on the concentration of the two clay ingredients.
Example 11: Comparison with the use of Laponite™ RD and Bentopharm as thickening agent of Suspension Concentrate containing azoxystrobin. Product used for this study
Laponite™ RD 5% wt. was prepared as previously described (see example 3 above) Bentopharm 10% wt. was prepared as previously described (see example 1 above) 7 days before this study
Millbase containing azoxystrobin as active ingredient and anionic dispersant used corresponds to the batch OP I001 -006-001
Preparation of the SCs
Ingredients were then mixed in the following order according to the following recipe:
Figure imgf000063_0002
1. Water 2. Millbase #1 (comprising an anionic dispersant, 6% by mass Morwet™ D425, and an active ingredient, the fungicide Azoxystrobin at 50% by mass dispersed in water)
3. Laponite™ EP 2% (w/w) gel 4. Bentopharm™ 10% (w/w) gel
5. Propylene glycol Stir until complete homogenisation with magnetic stirrer.
Figure imgf000064_0003
Rheological test protocol Oscillations and flow ramp test The rheological test protocol used for this study was the same as previously described for example 1.
Results - initial rheological tests on the suspension concentrate (flow ramp and oscillation tests) Table 36 shows the results of the fit of the flow ramp up with a Casson model, thus the
Casson yield stress and the infinite viscosity. Table 37 shows the results of the strain sweep performed thus the elastic and loss moduli on the linear viscoelastic range as well as the critical strain.
Table 36
Figure imgf000064_0001
Table 37
Figure imgf000064_0002
The use of Laponite™ RD is not suitable for the formulation of suspension concentrate containing azoxystrobin and anionic dispersant: the yield stress is too low to prevent sedimentation of the active ingredient. Although the elastic modulus is acceptable, the critical strain is too high. Hence, the gel stays stable at strains where some molecular rearrangements are expected. Similar results were found when using Laponite™B (Laponite containing inorganic fluoro compounds according to BYK). In fact, the flow ramp experiment performed in presence of Millbase #1 containing Azoxystrobin shows that the combination of Laponite™ B and Bentopharm™ features a low Casson yield stress (below 2 Pa) even with 20g/L of Bentopharm™ compared to Laponite™ EP and Bentopharm™. No significant difference was found on the elastic and loss modulus between the use of Laponite™ EP or Laponite™ B combined with Bentopharm™ in presence of Azoxystrobin.
Some variations between the use of Laponite™ EP or Laponite™ B relating to the stability of the gel were observed with time. A phase separation appeared for the formulation containing 5 g/L of Laponite™B and lOg/L Bentopharm™ whereas the gel stayed more stable with Laponite™EP 5g/L and lOg/L Bentopharm™.
Example 12: Thermal characterization of Laponite™ RD and Laponite ™EP
Product used for this study
Laponite™ RD and Laponite™ EP from BYK where used without any previous treatment. Experiment performed
Thermal gravimetric analysis (TGA) was performed by the University of Oxford Surface Analysis Facility using a Mettler Toledo TGA/DSC system under nitrogen from 30°C to 1000°C at a rate of 10°C/min.
Differential scanning calorimetry (DSC) experiments were performed using a DSC Q20 from TA Instruments under nitrogen and in aluminium pan closed with a lid having a pin hole according to the following heat-cool-heat protocols: a) For Laponite™ RD
1) Equilibration at -40°C
2) Ramp up to 400°C at 10°C/min
3) Ramp down to -40°C at 10°C/min
4) Ramp up to 400°C at 10°C/min b) For Laponite™ EP
1) Ramp up from 40°C to 400°C at 10°C/min
2) Ramp down from 400°C to 40°C at 10°C/min 3) Ramp up from 40°C to 400°C at 10°C/min
TA Universal analysis software was used to collect the data from the DSC experiment and to analyse them afterwards.
Results TGA and DSC
Results from TGA and DSC analysis for Laponite™ EP and Laponite™ RD are presented below in Figure 34 and Figure 35. Figure 34 presents the mass loss obtained from TGA. Figure 35 shows the 1st heat flow curves from the DSC analysis. Note that for all heat flow curves, exotherms point upward.
Curves of the heat flow curve obtained from the DSC experiments are in line with the one obtained from TGA and show an endothermic peak between 100°C and 120°C for both Laponite™ RD and Laponite™ EP accompanied by a loss of mass. This endothermic peak corresponds to the loss of water in the interlayer of the clay which is weakly bound to it according to Green et al. 1970, M. Silva et al. 2019 and Daniel et al. 2008.
Figure 34 reveals a graduate loss of mass from 150°C to about 700 °C for Laponite™ RD and from about 300°C to 700°C for Laponite™ EP which may correspond to further loss of the interlayer water according to the authors quoted above. However, the DSC heat flow curve of Laponite™ EP shows an exothermic peak at about 293.86°C. This may be due to some decomposition of the organic matter coating the surface of laponite. Guimaraes et al. (2006) and Gonzalvez et al. (2017) also reported such exothermic peak on grafted laponite. As revealed by TGA, another endothermic peak followed by an exothermic peak are observed at 730°C and 750°C respectively for Laponite™ RD and at 740°C and 760°C respectively for Laponite™ EP. These peaks have also been reported in the literature by the same authors and are due to some dihydroxylation (leading to the endothermic peak) followed by a recrystallisation according to Green et al. 1970. It is worth noting that these peaks happen at similar temperature for the coated and the non-coated Laponite which may indicate that the transformation undergone by Laponite™ EP is to the surface coating only and that its bulk structure may not have been impacted. Example 13: Characterization of the organic coating of Laponite ™EP by reflectance 13C NMR
Product used for this study Laponite™ EP powder from BYK was used for CP-MAS 13C NMR.
Experiment performed
Cross-Polarization-Magic Angle Spinning (CP-MAS) solid state 13C NMR was performed using an AVIIIHD bruker wide bore 400MHz at 10kHz.
Analysis of the spectra was performed using MestReNova software using the auto peak picking tool.
Results Figure 36 shows the spectrum obtained from the CP-MAS 13C NMR of Laponite™ EP.
The spectra reveals 4 peaks. The first peak at 6=174.54 ppm may correspond to some carboxyl maybe bonded to Laponite. In fact, Hunt et al. 1990 identified such peaks on various metal carboxylate complexes.
The second peak found at 6=102.36 ppm might correspond to an unsaturated C=C bond or a nitrile function CºN.
The 3rd peak shown at 6=73.72 ppm may correspond to saturated carbons (-CH2-) present in the molecule. The high intensity of the peak suggests that the coating features more than one -CH2 - group.
The 4th peak at 6=21.27 and 6=25.12 ppm are located in the region characteristics of alkyl groups and may correspond to the methyl group -C¾ as described by Wattel-Koekkoek et al. 2000, who found peaks at about 23 ppm associated with -CH3.

Claims

1. A particle gel comprising particles of a first clay, particles of a second clay and a liquid phase, wherein the second clay is different from the first clay and the second clay comprises an organic modification.
2. A particle gel according to claim 1 wherein the organic modification is a hydrophilic organic modification.
3. A particle gel according to claim 1 or claim 2 wherein the particles of the first clay and the particles of the second clay form a house of cards structure.
4. A particle gel according to any one of claims 1 to 3 wherein the particle gel is a non-Newtonian fluid.
5. A particle gel according to any preceding claim wherein the yield stress of the particle gel is from 1 to 10 Pa; the infinite viscosity of the particle gel determined using a fit of the stress us strain rate curve using a Casson model is less than 100 mPa.s; the viscosity of the particle gel at a shear rate of 20 s-1 is less than
420 mPa.s; the viscosity of the particle gel at a shear rate of 10 s 1 is less than 700 mPa.s; the elastic modulus G' of the particle gel is between 10 and 50 Pa; and/or the critical strain (’/critic) of the particle gel is about 0.01.
6. A particle gel according to any preceding claim wherein the average particle size of the particles of the first clay is larger than that of the particles of the second clay.
7. A particle gel according to any preceding claim wherein the particles of the first clay are microparticles and the particles of the second clay are nanoparticles.
8. A particle gel according to any preceding claim wherein the particles of the first clay have an average particle size of at least 1 pm, preferably wherein the particles of the first clay have an average particle size of from 1 to 10 pm.
9. A particle gel according to any preceding claim wherein the particles of the second clay have an average particle size of less than 1 pm, preferably less than 100 nm, more preferably wherein the particles of the second clay have an average particle size of from 10 to 50 nm.
10. A particle gel according to any preceding claim wherein the particles of the first clay are platelets and/or wherein the particles of the second clay are platelets, preferably wherein the particles of the first clay and the particles of the second clay are platelets.
11. A particle gel according to any preceding claim wherein the liquid phase comprises water.
12. A particle gel according to any preceding claim wherein the first clay does not comprise an organic modification.
13. A particle gel according to any preceding claim wherein the first clay is a water- swellable clay and the second clay is a water-swellable clay.
14. A particle gel according to any preceding claim wherein the first clay comprises a smectite clay and wherein the second clay comprises a smectite with an organic modification, preferably wherein the second clay comprises a hectorite clay with an organic modification.
15. A particle gel according to any preceding claim wherein the first clay comprises montmorillonite, optionally wherein the montmorillonite is a sodium montmorillonite.
16. A particle gel according to any preceding claim wherein the first clay is bentonite.
17. A particle gel according to any preceding claim wherein the second clay is a hectorite with an organic modification.
18. A particle gel according to any preceding claim wherein the first clay is bentonite and the second clay is a hectorite with an organic modification.
19. A particle gel according to any preceding claim wherein the second clay is LAPONITE™ EP.
20. A particle gel according to any preceding claim wherein the first clay is bentonite Bentopharm™ B20 and the second clay is LAPONITE™ EP.
21. A particle gel according to any preceding claim wherein the concentration of the first clay is between 0.01 and 10% by weight of the particle gel, preferably between 0.1 and 5% by weight of the particle gel.
22. A particle gel according to any preceding claim wherein the concentration of the second clay is between 0.01 and 5 % by weight of the particle gel, preferably wherein the concentration of the second clay is between 0.05 and 3% by weight of the particle gel.
23. A particle gel according to any preceding claim further comprising one or more active ingredients, optionally wherein at least one of the one or more active ingredients is dispersed in the particle gel or is present in the particle gel in emulsified form, optionally wherein the concentration of the at least one active ingredient dispersed in the particle gel or is present in the particle gel in emulsified form is from 0.1 to 60 % by weight of the particle gel.
24. A particle gel according to claim 23 wherein the one or more active ingredients are selected from agrochemicals, pigments, pharmaceuticals and cosmetic ingredients
25. A particle gel according to claim 24 wherein the one or more active ingredients are selected from agrochemicals, optionally wherein: the agrochemicals are selected from the group consisting of fungicides, insecticides and herbicides.
26. A particle gel according to any preceding claim further comprising a dispersant, preferably wherein the dispersant is a non-ionic or anionic dispersant.
27. A particle gel according to claim 26 wherein the concentration of the dispersant is from 0.1 to 20 % by weight of the particle gel.
28. A particle gel according to any preceding claim further comprising a surfactant, optionally wherein the concentration of the surfactant is from 0.1 to 20 % by weight of the particle gel.
29. A particle gel according to any preceding claim further comprising a salt, preferably wherein the salt is a salt of an active ingredient, optionally wherein the salt is a pesticide, insecticide, herbicide, fungicide salt, or the salt is an alkaline or alkali earth metal salt.
30. A particle gel according to claim 29 wherein the concentration of the salt is from 0.1 to 40 % by weight of the particle gel.
31. A particle gel according to any preceding claim further comprising a pH-modifying agent, wherein the pH of the particle gel is between 2 and 10.
32. A particle gel according to any preceding claim further comprising an anti-freezing agent, preferably wherein the anti-freezing agent is propylene glycol.
33. A particle gel according to claim 32 wherein the concentration of the anti -freezing agent is from 5 to 25% by weight of the particle gel.
34. A process for producing a composition for use in agriculture, which process comprises diluting a particle gel as defined in any one of claims 1 to 33 with water.
35. A composition for use in agriculture, wherein the composition is obtainable by diluting a particle gel as defined in any one of claims 1 to 33 with water.
36. A composition comprising a bentonite clay and a hectorite clay, wherein the hectorite clay comprises an organic modification.
37. An agrochemical formulation comprising
(a) a hectorite clay which comprises an organic modification, and
(b) one or more active ingredients, wherein at least one of the active ingredients is an agrochemical.
38. An agrochemical formulation according to claim 37 wherein at least one of the active ingredients is a salt of an agrochemical.
39. An agrochemical formulation according to claim 37 or claim 38 further comprising a surfactant as defined in claim 28, a dispersant as defined in claim 26 or claim 27, a salt as defined in claim 29 or claim 30, a pH modifying agent as defined in claim 31 and/or an anti-freezing agent as defined in claim 32 or claim 33, optionally wherein the agrochemical formulation comprises a further active ingredient which is an agrochemical as defined in claim 23 or claim 25.
40. Use of a particle gel as defined in any one of claims 1 to 33, a composition as defined in claim 35 or claim 36, or an agrochemical formulation as defined in any one of claims 37 to 39, as a plant protection product.
PCT/GB2021/051405 2020-06-08 2021-06-07 Clay compositions WO2021250383A1 (en)

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