Composition

Abstract

A liquid tank mix composition comprising: a polysaccharide; a carrier fluid; and a thickener wherein the one or more polysaccharides are present in an amount of at least 10% by weight wherein the carrier fluid is a low polarity oil and wherein the thickener is clay and / or silica.

Description

[0001] The present invention relates to a composition for polysaccharide delivery, a preparation method thereof and uses thereof.

[0002] Agrochemicals are bioactive materials such as herbicides, fungicides and insecticides that farmers and growers use to control weeds, as well as insect and fungal pests, in, on or around their crops. Typically, agrochemicals are provided as concentrates and are diluted with water prior to application to form the final composition to be applied. Recently, it has been recognized that for some applications, it may be advantageous to use more targeted agrochemical application rather than uniformly covering an entire area (such as a field). For all types of agrochemicals, it is also possible to allow much lower average levels of agrochemicals to be used across the field, thereby reducing the farmer's costs and the amount of agrochemicals in the environment. This targeted spray application is referred to as 'precision application'.

[0003] 'Precision application' is defined as applying agrochemicals to discrete portions of a target location rather than an entire area (broadcast application). Types of precision application include, but are not limited to, hooded / banded application, variable rate application using a prescription map, and optical spot spraying. Precision application also includes this type of targeted application in non-row crop type applications, such as in-furrow application or orchard spraying.

[0004] Thus, it has been found that polysaccharides in agrochemical compositions can provide enhanced spray retention in precision application scenarios. The polysaccharide concentration in the spray solution is typically about 0.1 (w / w), and the spray solution can be simply prepared on a laboratory scale by diluting an aqueous pre-gel (1%-2% w / w).

[0005] However, this dilution factor is not suitable on a commercial scale. For example, a 1000 L spray tank would require 50 L of 2% aqueous pre-gel, with a dilution factor of 20, which is not commercially suitable. Thus, the technical problem is how to effectively deliver the polysaccharide polymer into the spray tank for its final use in agrochemical applications.

[0006] Accordingly, there is provided a liquid tank mix composition comprising:

[0007] a. a polysaccharide;

[0008] b. a carrier fluid; and

[0009] c. a thickening agent,

[0010] wherein the one or more polysaccharides are present in an amount of at least 10% by weight, wherein the carrier fluid is a low polarity oil, and

[0011] wherein the thickening agent is clay and / or silica.

[0012] Thus, the composition according to the present invention provides a concentrated liquid formulation product that can be applied as a 'tank mix'. 'Tank mix' means a composition intended to be mixed with water in an agricultural chemical spray tank. Such tank mix compositions typically do not contain agricultural chemicals but are mixed in the spray tank with a composition containing agricultural chemicals.

[0013] Preferably, the formulation is an oil dispersion (OD). An oil dispersion is a dispersion of solid particles in a suitable organic carrier liquid.

[0014] It has been found that the composition according to the present invention shows improved physical stability, such as negligible separation upon storage while maintaining flowability. Negligible separation means less than or equal to 10% visual separation after 2 weeks (or even 4 weeks) at 25 °C.

[0015] It has been found that when diluted directly in water, such physically stable compositions form a suitably thickened spray solution. Thus, the oil dispersion serves as a convenient delivery vehicle for getting the polysaccharide into water.

[0016] The composition may not contain or may be substantially free of active ingredients.

[0017] Polysaccharide

[0018] Advantageously, one or more polysaccharides are selected from xanthan gum, guar gum, cellulose or its derivatives.

[0019] Advantageously, one or more polysaccharides are present in an amount of at least 12% by weight, such as at least 13% by weight, or at least 14% by weight.

[0020] Preferably, the polysaccharide is present in an amount of 12% to 60% by weight, even more preferably 15% to 55% by weight.

[0021] Having the polysaccharide concentration within this range significantly increases the dilution factor (e.g., for a 1000 L spray tank, a 40% w / w concentration would only require 2.5 L of the product and thus the dilution factor is 400).

[0022] Carrier fluid

[0023] The carrier fluid can be any non-aqueous liquid that has the desired non-solvent characteristics for the solids to be dispersed in the fluid. The carrier fluid is preferably an organic fluid, advantageously a low-polarity oil.

[0024] Low-polarity fluids (such as oils) are fluids with a dielectric constant less than 2.5.

[0025] The suspended polysaccharide should be insoluble or substantially insoluble in the carrier fluid, such as having a solubility of at most 700 ppm, preferably at most 500 ppm.

[0026] Hydrocarbons are generally suitable carrier fluids. For example, low-polarity oils can be paraffin oil or mineral oil. Suitable organic media include mineral spirits, mineral oil, aliphatic compounds, hexane, heptane, and white spirit. Suitably, the liquid is mineral oil, such as Sunspray Preferably, the carrier fluid is a low-polarity organic liquid, such as commercially available paraffin oil Sunspray

[0027] If the polysaccharide is insoluble in a carrier fluid with a relatively high dielectric constant, such a carrier fluid can be used. Advantageously, such more polar liquids can also have a relatively high water solubility, such that the solid can dissolve more rapidly when added to water. Examples are, for example, methylated rapeseed oil, oleic acid, dipropylene glycol dibenzoate or 200.

[0028] The carrier fluid is preferably present in an amount of from 20% to 90% by weight, such as from 30% to 80% by weight, from 35% to 70% by weight, or even from 40% to 60% by weight.

[0029] The composition preferably contains less than 10% by weight, such as less than 5% by weight, less than 1% by weight, or even less than 0.5% by weight of water.

[0030] Thickening agent

[0031] To stabilize the dispersion of the solid polysaccharide against sedimentation in the carrier fluid, one or more thickening agents are required. The thickening agent can be inert solid particles. Preferably, the thickening agent is a clay, such as one or more organoclays.

[0032] Advantageously, the thickening agent is present in an amount of from 0.001 - 5% by weight, such as from 0.01% to 3% by weight, or from 0.1% to 2% by weight.

[0033] Natural clays such as montmorillonite, attapulgite, and illite (which exhibit significant base exchange capacity) can be modified by treatment with long-chain amines and made hydrophobic. These are known as organoclays. Organoclays can be made from natural attapulgite, smectite, hectorite, or montmorillonite clays.

[0034] Any suitable organoclay thickening agent can be used in the present invention.

[0035] The organoclay thickening agents used in the present invention can be selected from the group consisting of: organically modified bentonite, hectorite, and smectite clays, such as tetraalkylammonium bentonite (e.g., Bentone TM 34), tetraalkylammonium hectorite (e.g., Bentone TM38), tetra(alkyl / aryl)ammonium bentonite (e.g., Bentone TM SD-1, Bentone TM 52, Bentone TM 120 and Bentone TM 1000), alkyl-aryl ammonium lithium montmorillonite (e.g., Bentone TM SD-3). Suitably, the organic clay thickener is selected from the group consisting of: tetraalkylammonium bentonite, tetraalkylammonium lithium montmorillonite, and tetra(alkyl / aryl)ammonium bentonite. Suitably, the organic clay thickener is tetraalkylammonium bentonite. Suitably, the organic clay stabilizer is tetraalkylammonium lithium montmorillonite. Suitably, the organic clay stabilizer is tetra(alkyl / aryl)ammonium bentonite.

[0036] The thickener (if it is clay) can be activated before its addition. The terms 'activator' and 'activation' refer to the formation of a gel structure in the clay. The activating substance can be present in an amount of 0.3% to 10% by weight.

[0037] Chemical or polar activators can help disperse the (organic) clay and act as an anti-settling system with good gel strength and physical stability. The term polar activator refers to a molecule that can activate the organic clay stabilizer so that it forms a gel structure. For example, methanol, propylene carbonate, and water.

[0038] It has been found that the clay can be activated in situ or before being added to the composition, preferably before addition. Examples of amine salts for modifying the clay are salts of isopropylamine, cyclohexylamine, and methylcyclohexylamine, such as bromides and acetates. When modifying the clay by treatment with an amine salt, it is preferred to incorporate an anionic surfactant into the composition. The anionic surfactant can be neutralized with a suitable amine such as alkyl C10 amine or cycloalkylamine or alkylcycloalkylamine. Particularly preferred are alkyl aryl sulfonates, such as alkyl benzene sulfonates and alkyl naphthalene sulfonates. Even more particularly preferred are the isopropylamine salts, cyclohexylamine salts, and methylcyclohexylamine salts of alkyl benzene sulfonates.

[0039] The degree of activation of the organic clay can be related to the clay gel strength and physical stability, since the amount of gelling in the system can be controlled by changing the ratio of the clay and the amine-neutralized surfactant, and also by replacing a portion of the amine-neutralized anionic surfactant with an appropriate amount of a conventional anionic surfactant (such as the alkali metal or alkaline earth metal salts of anionic surfactants). The gelling should be sufficient to keep the substantially insoluble solid components in suspension without making the composition too thick to be used.

[0040] Such formulations can be produced by any conventional wet milling method which will produce a satisfactory reduction in the particle size of the solid material. Examples are sand mills and bead mills. Alternatively, the solid material can be dry milled before being formulated into a mixture of pre-gelled material. Alternatively, an active material of suitable particle size can be dispersed into a mixture of pre-gelled material by high shear equipment.

[0041] Clays suitable for use with low polarity organic systems can be activated by certain emulsifiers rather than polar substances. In these cases, activation by emulsifiers can produce an anti-settling system with better physical stability and / or extended storage stability compared to activation using polar activators. In addition, the addition of glycol ethers can improve the physical stability of the dispersion. Any suitable glycol ether can be used, but preferably includes Dowanol PnB, propylene glycol and n-butyl ether. The ratio of glycol ether to organic clay stabilizer can be between 100:1 and 1:100 by weight, preferably 10:1 to 1:10 w / w. Such as about 2:1 w / w. Glycol ethers can be added to supplement or replace polar activators.

[0042] Organic clay thickeners suitable for use with low polarity liquids are organically modified attapulgite, hectorite, smectite, bentonite or montmorillonite clays. The clay is preferably organically modified to make it organophilic and suitable for use in organic media.

[0043] Also suitable thickeners are silica, preferably fumed silica (e.g., Cab-O-Sil) or precipitated silica (Sipernat 50 TM ); aluminum stearate; and / or hydrogenated oils.

[0044] In addition, mixtures of these thickeners can be used, advantageously, the composition can contain clay and silica. An example of this case would be a mixture of bentonite and silica (e.g., in a ratio of 3:1 to 1:3).

[0045] Emulsifier

[0046] An emulsifier can be added to the formulations of the present invention. The term 'emulsifier' is used herein to include all forms of surfactants (e.g., anionic, nonionic and zwitterionic surfactants).

[0047] Emulsifiers are used in the composition to emulsify water-insoluble organic liquids and facilitate the release of the dispersed solids into the aqueous phase so that they effectively and rapidly form their desired rheological properties. Thus, the emulsifier can contribute to the process. In principle, any emulsifier can be used.

[0048] The use of such emulsifiers can also activate organoclay thickeners. Such emulsifiers can include alkyl ethoxylates, alkyl ethoxylate phosphates, alkyl sulfates, alkyl ammonium salts, and castor oil ethoxylates.

[0049] Anionic surfactants can be used as part of the gel system (as described above) and are routinely balanced with nonionic surfactants to provide optimal emulsification for such formulations under a wide range of use conditions. Suitable nonionic surfactants that can be included in the compositions of the present invention are condensation products of fatty acid esters, fatty alcohols, fatty acid amides, or fatty amines with ethylene oxide and / or propylene oxide, condensation products of alkyl-, alkenyl- or polyaryl-substituted phenols with ethylene oxide and / or propylene oxide, fatty esters of polyol ethers (such as sorbitan fatty acid esters), condensation products of such esters with ethylene oxide such as polyoxyethylene sorbitan fatty acid esters, block copolymers of ethylene oxide and propylene oxide, ethoxylated lanolin alcohols or ethoxylated lanolin acids.

[0050] Advantageously, the emulsifier is Emulsogen

[0051] The emulsifier can be present in an amount of from 0.5% to 30% by weight, such as from 0.6% to 25% by weight, from 0.7% to 20% by weight, from 0.8% to 15% by weight, or even from 1% to 10% by weight.

[0052] Compositions and Uses

[0053] There is also provided a composition comprising an active ingredient, water, and a composition as described herein, which composition advantageously exhibits reduced breakup. Preferably, the polysaccharide is present in an amount of from 0.001% to 1% by weight.

[0054] ‘Droplet breakup’ is defined as the rupture of primary droplets of a nominal diameter upon impact with a surface, which subsequently results in a higher number of smaller secondary droplets that fall outside the initial impact area. Thus, ‘reduced breakup’ is defined as the percentage reduction in the total number of secondary droplets due to a change in composition or a change compared to a reference composition.

[0055] The terms ‘agrochemical’ and ‘active ingredient’ are used interchangeably and include herbicides, fungicides, and insecticides used by farmers and growers to control weeds, as well as insect and fungal pests, in, on, or around their crops.

[0056] There is also provided a precision application device in combination with the above-described composition with reduced breakup.

[0057] A method for preparing a composition as described herein is provided, which preferably includes high-shear mixing of a polysaccharide solid with a suitable carrier fluid and a thickening system under high-shear mixing. Suitable high-shear mixing can be provided by equipment familiar to those skilled in the art, such as an IKA overhead mixer and a wet bead mill. Advantageously, the method is carried out at a temperature of 10 °C to 80 °C.

[0058] The use of the composition as described herein as a tank mix to reduce the breakup of agrochemical compositions is also provided. Preferably, the composition as described herein is used for precision agriculture applications.

[0059] Unless otherwise stated, percentages are given as percentages by total weight, and all examples and preferred features can be combined in any combination.

[0060] The present invention is described by the following non-limiting examples.

[0061] Example

[0062] Definitions of related components are listed in Table 1.

[0063] Table 1

[0064]

[0065] [[ID=...]]

[0066] A pre-gel of a thickener and a carrier fluid was prepared according to the following.

[0067] A 1.5% w / w pre-gel of Bentone 38 in Sunspray 11N was prepared by charging Sunspray 11N (174 g) into a temperature-controlled 500 mL vessel equipped with a Silverson high-shear mixer and mixing at 4000 rpm at 25 °C.

[0068] Bentone 38 (3.04 g) was added and mixed for 10 minutes at 25 °C. Propylene carbonate (0.30 g) was added and mixed for 10 minutes at 25 °C. Finally, Emulsogen M (22.8 g) was added and mixed for an additional 10 minutes at 7500 rpm, then cooled to 20 °C.

[0069] Unless otherwise stated, formulations containing Bentone 38 and Sunspray 11N use this pre-gel at the stated dilution level.

[0070] Physical stability assessment of the oil dispersion

[0071] ​Visual inspection of the polysaccharide oil dispersion is carried out according to certain storage criteria, typically at 25 °C. The separation percentage is judged by visual inspection.

[0072] Prepare a 40% w / w KELCO-VIS oil dispersion with Bentone 38

[0073] Charge Sunspray 11N (13.5 g) into a 50 mL container equipped with an IKA overhead mixer and a serrated paddle and mix at 600 rpm. Add 1.5% w / w pre-gel of Bentone 38 (16.5 g) and mix for 5 minutes. Add KELCO-VIS DG (20.0 g) powder within 10 minutes and mix for another 15 minutes at 800 rpm.

[0074] This procedure is illustrated for a 40% w / w gellan gum example and is used to prepare the various polysaccharide oil dispersions described in Examples 1A to 1E, 2A - 2D and 3A - 3F listed in Tables 2 and 3.

[0075] Table 2 shows the separation percentage of the gellan gum slurry after 2 weeks at 25 °C. In all cases, the carrier fluid is Sunspray 11N, the thickener is Bentone 38, and the polysaccharide is gellan gum. For all entries, the ratio of Bentone 38 to Emulsogen M is 1:7.5.

[0076] Table 2

[0077]

[0078]

[0079] Therefore, it can be seen that it is necessary to optimize the thickener dosage to maintain physical stability while still ensuring flowable characteristics. For example, 1B and 1D are physically stable and flowable compositions. In contrast, Examples 1A and 1C show that physical stability has not been achieved, while 1E shows that too much thickener has led to the formation of a non-flowable paste.

[0080] Prepare a 40% w / w KELCO-VIS oil dispersion with Bentone 38 and Sipernat 50

[0081] Charge 50 mL container equipped with an IKA overhead mixer and a serrated blade with Sunspray 11N (13.25 g) and mix at 600 rpm. Add Bentone 38 1.5% w / w pre-gel (16.5 g) and mix for 5 minutes. Add SIPERNAT 50 (0.25 g) and mix for 5 minutes. Add KELCO-VISDG (12.1 g) powder within 10 minutes and mix for an additional 15 minutes at 800 rpm. This procedure is illustrated for a 40% w / w optimized gum and is used to prepare the various polysaccharide oil dispersions described in Examples 3G - 3L shown in Table 3.

[0082] Table 3 shows the separation % after 4 weeks at 25 °C for various polysaccharide compositions. For all entries, the polymer concentration is 40%, Emulsogen M is 3.75%, Bentone 38 is 0.50% or Bentone 38 (0.50%) and Sipernat 50 (0.50%), and Sunspray 11N is used as the carrier fluid.

[0083] Table 3

[0084]

[0085]

[0086] As can be seen in Table 3, by selecting a suitable thickener system, various polysaccharides can be formulated into physically stable oil dispersions.

[0087] Dilution of polysaccharide oil - dispersions in water

[0088] Example 4A was prepared as follows: Mix optimized gum (10 g) with deionized water (990 g) under high - shear mixing for 20 minutes to obtain a 1% aqueous pre - gel. Mix 10 g of this 1% w / w pre - gel with 90 g of deionized water to obtain a 0.10% optimized gum aqueous solution.

[0089] Example 4B was prepared by pipetting 0.50 g of 1B into water (99.50 g) using a magnetic stir bar with gentle stirring. Let the formulation stand for 5 minutes to allow the polysaccharide particles to hydrate and thicken the aqueous fluid.

[0090] Example 4C was prepared by pipetting 0.25 g of 1D into water (99.75 g) using a magnetic stir bar with gentle stirring. Let the formulation stand for 5 minutes to allow the polysaccharide particles to hydrate and thicken the aqueous fluid.

[0091] Table 4 presents the shear viscosity data for aqueous pre - gels of 1% optimized gum or aqueous solutions of optimized gum (0.10%) prepared using Examples 1B and 1D.

[0092] Table 4

[0093]

[0094] Table 4 shows that, regardless of the preparation method by dilution of the previously employed fully aqueous pre-gel (Example 4A) or the polysaccharide oil dispersion according to the invention (Examples 4B and 4C), the final aqueous solution (0.10%) containing gellan gum exhibits the same rheological properties.

[0095] Evaluation of spray retention performance

[0096] The spray solution is prepared by thoroughly mixing the required components defined in the table below. In all cases, the balance to 100% by weight is water.

[0097] Sulfacid Blue 5J is introduced into the spray solution at a final concentration of 0.5% w / w.

[0098] Spray evaluation

[0099] To evaluate the effectiveness of the polysaccharide in reducing the breakup of the composition, a custom spray evaluation method was developed. A custom static spray device was built and equipped with a spray nozzle operating at 3.0 ± 0.1 bar. Unless otherwise stated, the target surface is located 10 cm below the nozzle tip, i.e., a circular synthetic fabric substrate (D = 20 mm) on a cylindrical support (20 mm × 80 mm). The contact angle of this surface with deionized water is 133 ± 2°, and it is used to replicate a leaf surface that is difficult to wet.

[0100] The formulation is loaded into the spray device, and the operating parameters are adjusted to ensure that a 14 ± 1 mg dose of the spray solution is applied to the target. Below the supported target surface is an A4 paper, which is used to capture the un-retained spray, assisted by blue dye visualization. For each spray scenario, a total of 10 spray events are collected (e.g., repeated 10 times on 10 sheets of paper).

[0101] The breakup performance is evaluated as follows. The 10 A4 capture papers are digitized using a Brother DS-720D scanner operating at 600 dpi. Subsequently, custom ImageJ macros are used to analyze the digitized data to collate information on the number of droplets, coordinates, and area. The performance is evaluated by analyzing the total number of droplets, where breakup reduction is characterized by the percentage reduction in the total number of droplets.

[0102] Example 5A was prepared as follows. 1.5% of Bentone 38 in Sunspray 11N (0.25 g) was pipetted into deionized water (99.25 g) and gently mixed for 5 minutes. Sulfacid blue 5J (0.50 g) was added and mixed for an additional 5 minutes before spraying.

[0103] Examples 5B - 5D were prepared by pipetting 0.25 g of 3B, 3I, or 3E into water (99.25 g) using a magnetic stir bar with gentle stirring. The formulation was allowed to stand for 5 minutes to allow the polysaccharide particles to hydrate and thicken the aqueous fluid. Sulfacid Blue 5J (0.50 g) was added with gentle mixing for 5 minutes.

[0104] Table 5 presents a summary of the data on the spray evaluation of various polysaccharide oil dispersions. Each spray solution was prepared by diluting a 40% polysaccharide oil dispersion in water to a final concentration of 0.10%. The control (5A) was an oil dispersion formulation without any polysaccharide.

[0105] Table 5

[0106] Example Formulation Total number of droplets Reduction % 5A Control 2433 - 5B(3B) Gellan gum 9 99.3 5C(3I) Jaguar HP 60 3 99.9 5D(3E) PPEM 9575 11 99.5

[0107] Table 5 shows that each polysaccharide oil dispersion of the present invention, once diluted in water, is capable of providing a significant reduction in the total number of droplets desired (i.e., a reduction of greater than 50%, preferably greater than 85%), and thus can reduce the breakup of the spray droplets of the agrochemical composition upon impact with a surface.

[0108] Thus, it can be seen that the compositions of the present invention provide concentrated and stable polysaccharide formulations that are suitable for precision agriculture applications (among others).

[0109] The present invention is defined by the claims.

Claims

1. A liquid tank mix composition, comprising: a. a polysaccharide; b. a carrier fluid; and c. a thickener, wherein the one or more polysaccharides are present in an amount of at least 10% by weight, wherein the carrier fluid is a low-polarity oil, and wherein the thickener is clay and / or silica.

2. The composition according to claim 1, which is an oil dispersion (OD).

3. The composition according to claim 1 or 2, wherein The polysaccharide is present in an amount of 15% to 55% by weight.

4. The composition according to any one of the preceding claims, wherein, The one or more polysaccharides are selected from xanthan gum, guar gum, cellulose or derivatives thereof.

5. The composition according to any one of the preceding claims, wherein, The composition comprises less than 10% by weight of water.

6. The composition according to claim 5, wherein, The low-polarity oil is mineral oil.

7. The composition according to any one of the preceding claims, wherein The thickener is clay and silica.

8. The composition according to any one of the preceding claims, wherein, The thickener is present in an amount of 0.001% to 5% by weight.

9. The composition according to any one of the preceding claims, the composition comprising (d) an emulsifier.

10. The composition according to claim 9, wherein, The emulsifier is present in an amount of 1% to 10%.

11. A composition comprising an active ingredient, water and the composition according to any one of claims 1 to 10, the composition exhibiting reduced breakage.

12. The composition according to claim 11, wherein, The polysaccharide is present in an amount of 0.001% to 1% by weight.

13. A precision application device and the composition according to claim 11 or 12.

14. A method of preparing the composition according to any one of claims 1 to 10, the method comprising high-shear mixing of the components.

15. Use of the composition according to any one of claims 1 to 10 as a tank mix to reduce breakage of an agrochemical composition.

Images