Patent Application
20210368783
The invention relates to a herbicide formulation. In particular, the invention is directed to a herbicide formulation containing salts of 2,4-dichlorophenoxyacetic acid (2,4-D).
The herbicide 2,4-D has been known as a systemic selective herbicide for weeds, especially broad-leaf weeds, since the 1940s. This herbicide has been used in a wide range of formulations to control weeds, especially in grasses and cereal crops, but also in non-crop situations.
More recently, 2,4-D formulations have been in use, usually as liquids, in which the active ingredient is high—over about 70% w/v. However, when exposed to low temperatures approaching zero Celsius, such highly loaded formulations can become partially or entirely crystallised. Crystallisation is undesirable. It can reduce the effectiveness of the herbicide. It can result in clogging of spray equipment.
It is therefore an aim of the invention to provide a liquid 2,4-D herbicide formulation at a relatively high concentration which is crystallisation tolerant at low temperatures.
Accordingly, the invention provides a liquid herbicide formulation comprising:
wherein the formulation includes at least 600 g/L of 2,4-D; and
wherein the quantities of the alkylamine salts, the alkoxylate surfactant and ethylene glycol are such that the formulation resists crystallisation at a temperature of about minus 4° C. to 0° C.
Preferably, the alkoxylate surfactant is an ethoxylated fatty amine or a copolymer alkoxylate. The ethoxylated fatty amine is preferably ethoxylated tallow amine, such as available under the trademark Terwet 3780. An example of an effective amount is about 20 g/L. It is preferred that the ethoxylated fatty amine, if present, does not exceed about 40 g/L.
The copolymer ethoxylate is preferably that available under the trademark Teric BL-8. An example of an effective amount is about 20 g/L.
In both cases, higher or lower amounts of the alkoxylate surfactant may be effective, as will be apparent to a person skilled in the art.
Other surfactants may also be suitable.
Optionally, the formulation may also contain an effective amount of an anti-foaming agent, such as Antifoam A, up to about 1%.
Preferably, the formulation is provided as a soluble liquid (SL).
The formulation is highly loaded with active ingredient, having at least 600 g/L of 2,4-D. In preferred embodiments, the formulation has about 700 g/L, and especially 720 g/L of 2, 4-D.
It is also preferred that the formulation has between 40 and 60 g/L of isopropyl amine (70%). The more preferred quantity is about 45 g/L.
The formulation may have up to about 250 g/L of dimethylamine, more preferably between 100 and 150 g/L of dimethylamine.
The formulation may include from 80 to 100 g/L of diethylamine.
The formulation preferably contains from 20 g/L to 50 g/L of ethylene glycol.
The formulation may have a density of 1.234 g/cm3 at 20° C. In addition, the formulation may have a pH of 9.4 at 20° C.
The molar ratio of the amine salts to 2,4-D is preferably within the range 0.9 to 1.2.
It has been found that the formulation of the invention can advantageously inhibit crystallisation in zero to sub-zero temperatures.
The formulation may inhibit crystallisation when the temperature is about 0° C. Moreover, the formulation may inhibit crystallisation when the temperature is about −2° C. to 0° C. Furthermore, the formulation may inhibit crystallisation when the temperature is about −4 to 0° C.
As illustrated by the examples below and the comparisons in FIG. 1, the formulation details being in FIG. 2, crystallisation may be inhibited when the formulation combines isopropyl amine with dimethylamine or when diethylamine is combined with dimethylamine. When isopropyl amine is present, it is preferably more than about 4% of the formulation.
In order that the invention may be more readily understood and put into practice, one or more preferred embodiments thereof will now be described.
The composition of the herbicide formation according to one embodiment of the invention is shown in Example 1 below.
The composition of the herbicide formation according to a second embodiment of the invention is shown in Example 2 below.
The composition of the herbicide formation according to another embodiment of the invention is shown in Example 3 below.
Efficacy and Safety Studies
Tests were carried out to determine the properties and performance of the herbicide formulation of Example 1, when compared to those of other known herbicide formulations.
The herbicide products used in the studies are listed in Table 1 below.
The following six field trial studies were conducted to compare the efficacy and/or crop safety of the Example 1 formulation compared to ZULU evo 720 and Amicide Advance 700. The purpose was to establish whether the Example 1 formulation was bioequivalent with Zulu evo 720 and Amicide Advance 700 in efficacy and safety. The efficacy and safety of Zulu evo 720 was compared with that of Amicide Advance 700. Specific efficacy and/or crop safety tests were carried out to establish bioequivalence of the Example 1 formulation with Zulu evo 720.
The results of the trials demonstrated that the Example 1 formulation is bioequivalent to ZULU evo 720, and when applied as directed will provide good control in the situations intended.
The data presented also demonstrated that ZULU evo 720 is equivalent and/or superior to Amicide Advance 700. With equivalence of the Example 1 formulation and Zulu evo 720 established, bioequivalence of the Example 1 formulation with Amicide Advance 700 is also confirmed.
The Example 1 formulation's use pattern is derived from both the ZULU evo 720 and Amicide Advance 700 labels. Comparison of labels for all three products confirmed a significant proportion of analogous use patterns; therefore broader equivalence of the Example 1 formulation with Amicide Advance 700 could be expected.
Crystallisation Tests
The liquid formulations were tested at 0±2° C. or lower for more than seven days. The effect of low temperatures on stability were determined and reported according to Collaborative International Pesticide Analytical Council (CIPAC) method MT 39.3 (liquid formulations).
The formulations in Examples 1, 2 and 3 were tested with comparison formulations not falling within the scope of the invention. As indicated in each of Tables 2, 3 and 4 which follow the description below, the formulations in Examples 1, 2 and 3 are identified as AR-40B, AR-51C and AR-52B respectively.
Table 2 shows results for 2, 4-D 720 crystallisation testing at low temperatures. Out of the trials, the three formulations in Examples 1, 2 and 3 inhibited crystallisation of 2,4-D in water at concentration 720 g/L.
The details of the three formulations are shown in Table 3. It was noted that the combination of amines, proportions between them and ethylene glycol presence in the formulations played a main role in inhibition of crystallisation. Replacement of ethoxylated fatty amine by polyalkylene oxide derivative of a synthetic alcohol in the same quantity (Teric BL8) did not significantly reduce inhibition of crystallisation in the formulations of Examples 2 and 3.
The molar ratios of amines to 2,4-D in each of the formulations in Examples 1, 2 and 3, respectively were determined. The detailed results are shown in Table 4. The molar ratio for the Example 1 formulation was 0.988. The molar ratio for the Example 2 formulation was 1.035, while the molar ratio for the Example 3 formulation was 1.148.
The foregoing embodiments are intended to be illustrative of the invention, without limiting the scope thereof. The invention is capable of being practised with various modifications and additions as will readily occur to those skilled in the art.
Accordingly, it is to be understood that the scope of the invention is not to be limited to the exact construction and operation described and illustrated, but only by the following claims which are intended to include all suitable modifications and equivalents permitted by the applicable law.
The term “comprise” and variants of that term such as “comprises” or “comprising” are used herein to denote the inclusion of a stated integer or integers but not to exclude any other integer or any other integers, unless in the context or usage an exclusive interpretation of the term is required.
Reference to prior art disclosures in this specification is not an admission that the disclosures constitute common general knowledge.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2018201794 | Mar 2018 | AU | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/AU2019/000036 | 3/12/2019 | WO | 00 |
