Agrochemical composition

Abstract

A composition comprising an encapsulated agrochemical and an adjuvant blend comprising (a) a non-ionic alkylene oxide copolymer and (b) a terpenic alkoxylate.

Description

[0001] AGROCHEMICAL COMPOSITION

[0002] The present invention relates to agrochemical compositions and uses and methods of preparation of the same.

[0003] Microencapsulation is known in many fields of technology and are small capsules which comprise a wall which surrounds an encapsulated material, generally a liquid. They may be used for protecting the encapsulated material from the external environment, for example from degradation by air or light. They may also be used to isolate hazardous materials within the microcapsule to make them safer to handle or use. Microcapsules are known to be used for agrochemicals to protect them from degradation by UV light and to provide controlled release following application. In the agrochemical field, microencapsulation can be beneficial for example for controlling the rate of release of the active ingredient, to reduce volatile loss, to ensure chemical stability of the active ingredient, and / or to protect the operators from exposure to the active ingredients.

[0004] However, encapsulation of an agrochemical can reduce its biological efficacy by reducing the bioavailability to the target organism. This was found to be particularly the case for prosulfocarb, where encapsulation of the active ingredient in order to reduce off target movement resulted in a reduction in pre-emergence herbicidal activity.

[0005] There is therefore a problem where, for environmental benefits, agrochemicals must be encapsulated in order to reduce off target movement and volatile loss but that such encapsulation reduces the performance of the composition.

[0006] This invention seeks to address this technical problem and the present invention therefore provides a composition comprising an encapsulated agrochemical, (a) a non-ionic alkylene oxide copolymer and (b) a terpenic alkoxylate. It has surprisingly been found that such a composition improves the technical performance of an encapsulated agrochemical by reducing volatile movement without incurring an efficacy penalty.

[0007] By ‘encapsulated’ we mean that the agrochemical is enclosed and present within a microcapsule. Unless otherwise specified, the terms ‘encapsulation’ and

[0008] ‘microencapsulation’; and ‘capsule’ and ‘microcapsule’, are used interchangeably. The agrochemical may be encapsulated by any suitable method, preferably natural polymer coacervate microcapsules, synthetic multi-functional acrylate microcapsules, or polyurea microcapsules.

[0009] The microcapsules advantageously have a diameter of from 100nm to 50um, preferably from 1 pm to 30pm, most preferably from 5 pm to 20 pm.

[0010] Preferably the agrochemical is hydrophobic. The agrochemical may have an aqueous solubility of from 0.001 to 1000 ppm, such as from 0.004 to 500 ppm, from 0.01 to 400 ppm, from 0.1 to 300 ppm, or even from 1 to 200 ppm. The agrochemical may be thiamethoxam, metalachlor (e.g., s-metalachlor), tefluthrin, lambda cyhalothrin, clomazone, permethrin or prosulfocarb. Most preferably the agrochemical is prosulfocarb.

[0011] Without wishing to be bound by theory, it is believed that the described adjuvants are able to move the capsules deeper into the soil due to their soil wetting properties and thus be more proximate to the germinating seeds.

[0012] The non-ionic alkylene oxide copolymer may be present in the composition in a major amount and the terpenic alkoxylate is present in the composition in a minor amount.

[0013] In another aspect, the non-ionic alkylene oxide copolymer component is a non-ionic copolymer of ethylene oxide (EO) and propylene oxide (PO).

[0014] When used herein, the term "terpenic" in the context of the terpenic alkoxylate component is indicative of a moiety having terpenic origin. In a further embodiment, the composition of the invention may also contain water and / or one or more organic diluents such alkyl alcohols and / or glycols.

[0015] Preferably, in one embodiment, the composition of the present invention comprises:

[0016] (a) at least one non-ionic alkylene oxide copolymer represented by the formula (I)

[0017] R1-O-(CH2CH2O)x(CH(CH3)CH2O)y(CH2CH2O)z-R2 (I) wherein R1 and R2 are independently selected from hydrogen and linear or branched C1-C8 alkyl; and wherein the values of x, y and z are each other than zero and the sum of x, y and z is chosen so that there is from 10 to 80% of ethylene oxide (EO) present in the copolymer and where the number average molecular weight of the copolymer is from 1000 to 6500; and

[0018] (b) at least one terpenic alkoxylate selected from a compound of the formulae (II):

[0019] R3-O-(CH(R4)CH2O)n-(CH(R4)CH2O)m-R5 (II) wherein R3 is a terpenic moiety selected from the group consisting of terpenic carbides, oxidized derivatives of terpenic carbides (such as hydroformylation derivatives), terpenic alcohols, terpenic aldehydes and ketones, and mixtures thereof; R4 is selected from hydrogen and methyl (i.e., the -(CH(R4)CH2O)- units of the alkylene oxide moiety of formula (II) are selected from ethylene oxide (EO) and propylene oxide (PO) in either a block or random configuration); R5 is selected from hydrogen and linear or branched C1-C8 alkyl; and where n and m are each other than zero and wherein the sum of n and m is chosen so that there are from 2 to 10 propylene oxide units and from 5 to 25 ethylene oxide units.

[0020] In one embodiment, the non-ionic alkylene oxide block copolymer (a) has a number average molecular weight of from 1700 to 3500; more particularly, from 2200 to 2600.

[0021] In another embodiment, the EO percentage of ethylene oxide in the non-ionic alkylene oxide block copolymer molecule (a) can vary from 10 to 50; more particularly, from 10 to 30.

[0022] In one aspect, the non-ionic alkylene oxide block copolymer molecule (a) is an EO-PO-EO copolymer, having a molecular weight of about 2450, and wherein 20% of molecule is polyethylene glycol.

[0023] In one aspect, the terpenic moiety R3 is a moiety derived from monoterpenes, sesquiterpenes, diterpenes, and hydroformylation derivatives thereof. In particular, there may be mentioned the terpenes containing ten carbon atoms in their structure and, more specifically, acyclic, monocyclic or bicyclic monoterpenes. Among the suitable monoterpenes there are, for example, monocyclic terpenic carbides such as dipentene, terpinolene, p-cymene, limonene, etc.; bicyclic terpenic carbides such as a-pinene, p-pinene or b-3-carene, etc.; and terpenic alcohols such as borneol, fenchol, menthanol, terpineols, geraniol, etc.; hydroformylation derivatives thereof; and mixtures thereof.

[0024] In another aspect, in the terpenic alkoxylate of formula (II) the sum of n and m is chosen so that there are from 3 to 7 propylene oxide units and from 5 to 15 ethylene oxide units; more particularly, from 3 to 7 propylene oxide units and from 5 to 9 ethylene oxide units - in any case, in either a block or a random configuration.

[0025] In one embodiment, the terpenic alkoxylate of formula (II) is selected from a block copolymer of the formulae (Ila) or (lib):

[0026] R3-POn-EOm-R5 (Ila)

[0027] R3-EOn-POm-R5 (lib) In another embodiment, the terpenic alkoxylate of formula (II) is a random EO / PO copolymer (He):

[0028] R3-(random EO / PO)n+m-R5 (lie)

[0029] In a specific embodiment, the R3 moiety of formula (II) is derived from the hydroformulation of P-pinene so that the terpenic alkoxylate (b) is a Nopol alkoxylate wherein R4, R5, m and n are as defined above. In a more specific embodiment, the terpenic alkoxylate (b) is Nopol-(POn-EOm)-H, where Nopol is the hydroformylation product of - pinene, and wherein n=5 and m=7.

[0030] Suitably, in the composition according to the invention the ratio (% wt / v) of (a) to (b) is from 95:5 to 5:95. In one aspect, the alkylene oxide copolymer (a) is present in the inventive composition in a major amount and the terpenic alkoxylate (b) is present in said composition in a minor amount. In a particular embodiment, the ratio (% wt / v) of (a) to (b) is from 90:10 to 60:40.

[0031] The composition of the present invention may further contain (c) other inert additives such as standard formulation components and diluents. Such inert additives include flow enhancers, other wetting agents, antifoaming agents, biocides, drift control agents, deposition enhancers, adjuvants, evaporation retardants, freeze protecting agents, UV protecting agents, fragrances, and the like. Among the suitable diluents that are used in the invention there may be mentioned aliphatic alcohols and adducts thereof with alkylene oxides such as glycols and alcohols including ethanol, isopropyl alcohol and propylene glycol. A suitable amount of the optional diluents or flow enhancer is from zero to 20 % wt / v of the entire composition; more particularly, from zero to 10 % wt / v of the entire composition.

[0032] In another embodiment, the ratio (% wt / v) of (a): (b)+(c) is from 90:10 to 80:20.

[0033] Preferably, the adjuvant blend is present in an amount of from 5 to 70% by weight of the composition, such as from 6 to 65% by weight, from 7 to 60% by weight, from 10 to 50% by weight, or most preferably from 15 to 30% by weight.

[0034] In a second aspect of the invention there is also provided a tank mix comprising a composition as defined herein comprising water in an amount from 75 to 99.9% by weight, such as from 80 to 99.5% by weight. Accordingly, there is provided a method of preparing such a tank mix composition comprising (1) the addition of the encapsulated agrochemical and (2) the addition of the adjuvant blend in separate steps.

[0035] There is provided the use of an adjuvant blend as defined herein to improve the biological efficacy of an encapsulated agrochemical together with the associated reduction in drift of such a composition.

[0036] There is provided a method of protecting useful plants from insects, acarines, nematodes or molluscs, comprising applying to said plants, to the locus, including soil thereof, or to plant propagation material thereof, a composition as defined in herein.

[0037] There is also provided a method of controlling weeds at a locus, including soil, comprising applying to the locus a weed controlling amount of a composition as defined in herein.

[0038] Unless otherwise stated all percentages are given as percentages by total weight and all embodiments and preferred features may be combined in any combination.

[0039] The invention is described by the following non-limiting Examples.

[0040] Examples

[0041] Formulations

[0042] The following non-encapsulated and encapsulated formulations were prepared as set out in Tables 1 , 2 and 4. The adjuvant composition is as set out in Table 3.

[0043] Table 1 - Prosulfocarb EC formulation Table 2 - Encapsulated Prosulfocarb formulation [polyurea-based]

[0044] Table 3 - Qualibra ®

[0045] Table 4 - Encapsulated Prosulfocarb formulation [Acrylic-based]

[0046] Drift Testing

[0047] The variation in drift between Compositions 1 and 2 was tested as below.

[0048] Prior to application the soil was wetted so application was made onto wet soil. Treatments were applied to a 50 m2plot in a wind tunnel at a rate of 2.4 kg Al / ha in water volume of 200L / ha. Steel sampling bowls filled with 25 L tap water were placed 1 m, 3 m and 5 m from the treated area and covered. After the plot had been treated the bowls were uncovered and the fans at the opposite end of the wind tunnel turned on to generate wind speeds of 2 m / s for 6 days.

[0049] At 3 days post application the treated plot was re-moistened with a simulated rain event.

[0050] At 1, 2, 3 and 6 days after application (DAA) 50 mL samples were taken from each sampling bowl and the concentration of PSC measured for each. Table 5 gives the sum of PSC concentration in all bowls which represents the total drift potential of each formulation. Samples were frozen until analysis for PSC content.

[0051] Table 5

[0052] It can be seen that the encapsulated formulation exhibits a significant reduction in the drift of the agrochemical. This is the case even after the simulated rain event on day 3.

[0053] Efficacy Testing

[0054] Tank mix compositions were prepared in the concentrations according to the Treatment Numbers as set out in Table 6. All values are given as percentage by weight. Table 6

[0055] Efficacy was measured in field trials against two drilled weed species Alopecurus myosuroides (ALOMY) and Lolium multiflorum (LOLMLI). Each treatment was replicated across 3 plots each of 10m2area. The plots were treated pre-emergent using (using horizontal boom sprayer) at 1.6 and 2.8 kg of pesticide per hectare in a water spray volume of 300 litres per hectare. Some treatments also included Qualibra at either 1 or 5 litres per hectare which was added to the spray tank before application.

[0056] The efficacy of the treatments was assessed visually and expressed as a percentage of the weeds controlled compared to the untreated control plot. Samples were assessed at two time points: between 9 and 15 days after application (DAA) and 27 and 35 DAA. The results in Table 7 are mean averages over the three replicates for each treatment.

[0057] Table 7 It is seen that the use of the encapsulated composition in Treatments 2 and 6 results in a drop in efficacy relative to the non-encapsulated EC formulation in Treatments 1 and 5.

[0058] However, it has surprisingly been found that the presence of Composition 3 in Treatments 3, 4, 7 and 8 results in the improvement of the efficacy, at various rates, such that the encapsulation compositions comparative to the non-encapsulated treatments.

[0059] Accordingly, it can be seen that compositions according to the invention successfully counter the drop in performance associated with the encapsulation of the agrochemical.

[0060] It was also found that this effect is particular to the combination of encapsulated active ingredients and the described adjuvants.

[0061] As set out in Tables 8 and 9 below, four compositions were tested for efficacy as set out in the above methodology but with a water spray volume of 200 L / ha. Treatment 1 is the EC formulation, Treatment 2 is EC + adjuvant, Treatment 3 is an encapsulated active ingredient formulation and Treatment 4 is Treatment 3 plus adjuvant.

[0062] Table 8

[0063] Table 9 As can be seen, an increase in efficacy only occurs when combined with encapsulated active ingredient.

[0064] The invention is defined by the claims.

Claims

Claims1. A composition comprising an encapsulated agrochemical and an adjuvant blend comprising (a) a non-ionic alkylene oxide copolymer and (b) a terpenic alkoxylate.

2. A composition according to claim 1 , wherein the agrochemical is hydrophobic.

3. A composition according to claim 1 or 2, wherein the agrochemical is prosulfocarb.

4. A composition according to any of the preceding claims, wherein the agrochemical capsule has a size of from 100 nm to 50 pm.

5. A composition according to any of the preceding claims wherein the agrochemical is present in an amount of from 25 to 60% by weight.

6. The composition according to any of the preceding claims, wherein the non-ionic alkylene oxide block copolymer molecule (a) comprises at least one copolymer represented by the formula (I)Ri-O-(CH2CH2O)x(CH(CH3)CH2O)y(CH2CH2O)z-R2 (I) wherein Ri and R2are independently selected from hydrogen and linear or branched Ci-Cs alkyl; and wherein the values of x, y and z are each other than zero and the sum of x, y and z is chosen so that there is from 10 to 80% of ethylene oxide (EO) present in the copolymer.

7. The composition according to any of the preceding claims, wherein the terpenic alkoxylate (b) comprises at least one terpenic alkoxylate selected from a compound of the formula (II):R3-O-(CH(R4)CH2O)n-(CH(R4)CH2O)m-R5(II) wherein R3 is a terpenic moiety selected from the group consisting of terpenic carbides, oxidized derivatives of terpenic carbides, terpenic alcohols, terpenic aldehydes and terpenic ketones, and mixtures thereof; R4is selected from hydrogen and methyl; Rs is selected from hydrogen and linear or branched Ci-Cs alkyl; and where n and m are each other than zero and the sum of n and m is chosen so that there are from 2 to 10 propylene oxide units and from 5 to 25 ethylene oxide units.

8. The composition according to any of the preceding claims, wherein the ratio (% wt / v) of (a) to (b) is from 90:10 to 60:40.

9. A composition according to any of the preceding claims wherein the adjuvant blend is present in an amount of from 10 to 40% by weight.

10. A tank mix composition comprising a composition according to any of the preceding claims further comprising water in an amount from 75 to 99.9% by weight.

11. A method of preparing a tank mix composition according to claim 10, comprising (1) the addition of the encapsulated agrochemical and (2) the addition of the adjuvant blend in separate steps.

12. Use of an adjuvant blend as defined in any of claims 1 to 9 to improve the biological efficacy of an encapsulated agrochemical.

13. Use of an encapsulated agrochemical to reduce drift in a composition as defined in any of claims 1 to 9.

14. A method of protecting useful plants from insects, acarines, nematodes or molluscs, comprising applying to said plants, to the locus thereof, or to plant propagation material thereof, a composition as defined in any one of claims 1 to 10.

15. A method of controlling weeds at a locus, including soil, comprising applying to the locus a weed controlling amount of a composition as defined in herein.