AU2021105470B4 - Herbicidal Formulation with Improved Flowability - Google Patents

Abstract

The invention provides a highly loaded imazapic and hexazinone granular herbicidal formulation. The formulation includes a sequestrant present in a quantity sufficient to 5 prevent clumping. The loading of imazapic and hexazinone together may total about 90% of the formulation by weight. The sequestrant may be present at more than 2% by weight (preferably about 3% by weight). A dispersant, wetting agent and filler may also be included. 10 7

Description

Herbicidal Formulation with Improved Flowability

Technical Field

The invention described herein relates to a herbicidal formulation. In particular, the invention is directed to a formulation for a herbicide which includes as active

ingredients imazapic (5-methyl-2-(4-methyl-5-oxo-4-propan-2-yl-1H-imidazol-2-yl) pyridine-3-carboxylic acid) and hexazinone (3-cyclohexyl-6-(dimethylamino)-1-methyl

1,3,5-triazine-2,4-dione).

Background Art

Agricultural chemical products such as herbicides can undergo chemical and physical changes during storage. The rate at which these changes occur may depend on the

nature of the components, the formulation type, the packaging and storage conditions, including temperature, light and humidity.

In the case of a granular formulation, ingress of moisture or other problems may result

in clumping of the product and poor flowability from the container. The problem may be exacerbated when the formulation contains a high loading of active ingredients,

because there may be little 'room' in the formulation for adjuvants which may alleviate such problems.

It is an aim of the invention to provide an imazapic and hexazinone granular herbicidal formulation which overcomes or ameliorates one or more of the problems described

above, or which at least provides a useful choice.

Summary of the Invention

According to one aspect of the invention, there is provided an imazapic and

hexazinone granular or powdered herbicidal formulation wherein the formulation includes a sequestrant present in a quantity sufficient to prevent granular clumping.

In one embodiment, the imazapic and hexazinone together total about 90% of the formulation by weight.

Preferably, the sequestrant is present at or above about 2% by weight to about 3% by weight.

Preferably, the formulation also includes one or more surfactants. It is preferred that

the surfactant (or surfactants if more than one) are present at or above 5% by weight.

The range of about 5.1 to about 5.4% by weight is particularly preferred.

When there is more than one surfactant, one may be a dispersant and one may be a

wetting agent, for example.

The formulation may also include a filler.

It It is particularly preferred that the formulation includes a dispersant, a wetting agent

and a filler.

Each of the adjuvants, such as the sequestrant, the dispersant, the wetting agent and

the filler, may have more than one function. For example, a sequestrant may also function as a filler or binder, a dispersant may also function as a binder and a filler may

also function as a water absorber.

Preferably, the sequestrant is EDTA (ethylenediaminetetraacetic acid) or a suitable

salt, such as disodium ethylenediaminetetraacetate, disodium ethylenediaminetetraacetate dihydrate or tetrasodium ethylenediaminetetraacetate.

In one embodiment, EDTA is present in the formulation at about 3% by weight.

EDTA may also act as a filler or a binder.

In one embodiment, the formulation of the invention may include about 15% by

weight of imazapic. The formulation may include about 75% by weight hexazinone. Preferably, the formulation of the invention contains imazapic: hexazinone in the ratio

range of 1: 2 to 1: 10.

The herbicidal formulation of the invention is in the form of granules or a powder. In a

preferred embodiment the formulation is that of a water soluble granule (SG). However, the invention is not limited to this. Other versions of the formulation may include a water dispersible granule (WG), an emulsifiable granule (EG), a wettable

powder (WP) and a water-soluble powder (SP).

In an embodiment where there is more than one surfactant, one being a dispersant,

the dispersant may be any agriculturally suitable dispersant. In a preferred embodiment, the dispersant is a lignosulfonate, such as that sold under the trademark

Ufoxane 3A, available from Borregard, PO Box 162, 1701 Sarpsborg, Norway.

When the dispersant is a lignosulfonate, it may also function as a binder for the dried product.

In an embodiment where there is more than one surfactant, one being a wetting agent, the wetting agent may be any agriculturally suitable wetting agent. Preferably,

the wetting agent is an anionic wetting agent. In a preferred embodiment, the wetting

agent is an alkyl naphthalene sulfonate, such as that sold under the trademark Supragil WP, available from Solvay Interox Pty Limited, 20-22 McPherson Street, Banksmeadow, NSW, 2019, Australia.

The filler, if present, may be any agriculturally suitable material. The filler may also act

as a water absorber. Preferred is sodium sulphate, particularly anhydrous sodium sulphate.

The formulation of the invention should be packaged so as to meet commercial requirements and prevent the ingress of moisture. One suitable packaging is 5 Kg in a

10 litre jerry can with heat seal and screw cap.

Preferably, the combination of adjuvants in the formulation of the invention has the effect that moisture content in a sealed container is maintained at about 1% or less

Reference throughout this specification to 'one embodiment' or 'an embodiment' means that a particular feature, structure, or characteristic described in connection

with the embodiment is included in at least one embodiment of the present invention. Thus, the appearances of the phrases 'in one embodiment' or 'in an embodiment' in

various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristic described herein may be combined in any suitable manner in one or more

combinations.

Detailed Description of Preferred Embodiment

In one embodiment, a detailed breakdown of content of the formulation of the invention is provided in Table 1 below.

Table 1: Imazapic - Hexazinone SG Formulation

Content % Component Description of Component by weight

15.0 Imazapic active ingredient

75.0 Hexazinone active ingredient

3.6 Ufoxane 3A dispersant/binder

1.5 Supragil WP wetting agent

3.0 EDTA sequestrant/filler binder

1.9 Sodium Sulphate filler/water absorber

Storage Stability Testing Studies were undertaken to obtain information on the shelf life of the formulation

according to the preferred embodiment in Table 1 above. The APVMA Guidelines Generation of Storage Stability Data for Agricultural Chemical Products were followed.

In particular, a study was undertaken to examine the effect of accelerated storage on the stability of the product in commercial packaging material.

The test results are set out in Figure 1.

The test results show that the formulation will remain stable for extended periods of storage, without clumping and with good flowability. Advantageously, the water

soluble (SG) formulation described above can be stored in a jerry can with heat seal and screw cap.

The formulation is suitable for control of weeds in sugarcane, namely:

Awnless Barnyard Grass (Echinochloa colona),

Barnyard Grass (E. crus-galli),

Blackberry Nightshade (Solanum nigrum),

Blue Billygoat Weed (Ageratum houstonianum),

Calopo Vine (Calopogonium mucunoides) Common Sida (Sida rhombifolia),

Giant/Black Pigweed (Trianthema portulacastrum),

Glossy Nightshade (Solanum americanum),

Green Amaranth (Amaranthus viridis),

Green Summer Grass (Brachiaria subquadripara),

Ipomoea spp.,

Guinea Grass (Panicum maximum),

Liverseed Grass (Urochloa panicoides),

Milkweed (Mexican Fire Plant) (Euphorbia heterophylla),

Pigweed (Portulaca oleracea),

Sowthistle (Sonchus oleraceus) Summer Grass (Digitaria cilaris).

The formulation may be applied pre-emergently or post-emergently. One suitable rate is 500 to 630 g per hectare. When used as a directed spray (post-emergently), the

formulation may be mixed with paraquat.

The foregoing embodiments are illustrative only of the principles of the invention, and

various modifications and changes will readily occur to those skilled in the art. The

invention is capable of being practiced and carried out in various ways and in other embodiments. It is also to be understood that the terminology employed herein is for

the purpose of description and should not be regarded as limiting.

Reference to prior art disclosures in this specification is not an admission that the

disclosures constitute common general knowledge.

The term 'imazapic' as used herein in the specification and claims refers to the acid (5

methyl-2-(4-methyl-5-oxo-4-propan-2-yl-1H-imidazol-2-yl) pyridine-3-carboxylic acid).

Claims (5)

Claims

1. An imazapic and hexazinone granular or powdered herbicidal formulation, wherein the formulation includes a sequestrant present in a quantity sufficient to prevent clumping.

2. The granular or powdered formulation of claim 1, wherein imazapic and hexazinone together total about 90% of the formulation by weight and wherein the formulation also contains one or more surfactants present at about 5.1% to about 5.4% by weight, the sequestrant being present at or above about 2% to about 3% by weight.

3. An imazapic and hexazinone SG herbicidal formulation in which imazapic is present at about 15% by weight and hexazinone is present at about 75% by weight, wherein the formulation includes a sequestrant present at about 3% by weight, a dispersant, a wetting agent and a filler.

4. The SG formulation of claim 3, wherein the dispersant is a lignosulfonate, the wetting agent is an anionic wetting agent and the filler is sodium sulphate.

5. The SG formulation of any one of claims 1 to 4, wherein the sequestrant is EDTA (ethylenediaminetetraacetic acid) or a suitable salt, such as disodium ethylenediaminetetraacetate, disodium ethylenediaminetetraacetate dihydrate or tetrasodium ethylenediaminetetraacetate.

FIGURE 1 Analysis (T0) Analysis (TAS) Determination Method Specification storage condition - storage condition - 14d Result ambient @ 54 °C Appearance, Physical Visual Brown granules Brown granules Brown granules PASS State & Colour

Odour Olfactory Characteristic Characteristic Characteristic PASS

pH 1% v/v CIPAC MT 75.3 3.00 – 5.00 3.08 3.17 PASS 1.0 g / 100 mL Dust Content CIPAC MT 171 Max 30 mg 12 mg 18 mg PASS g Gravimetric 1/1

CIPAC MT 185 Wet Sieve Test (10 g) <2% No determined residue No determined residue PASS 75 µm sieve Attrition Resistance CIPAC MT 178.2 > 98 % 99.3 % 99.1 % PASS

Degree of dissolution After 5 mins < 1.0% After 5 mins no residue After 5 mins no residue CIPAC MT 179 PASS & solution stability After 18 hr < 0.05% After 18 hr no residue After 18 hr no residue Content Imazapic 141 - 159 g/Kg 147 g/Kg 149 g/Kg PASS QCM-114 Content Hexazinone 725 – 775 g/Kg 752 g/Kg 754 g/Kg PASS

Flowability after heat CIPAC MT 172.1 0.0 g after 5 liftings 0.0 g after 2 liftings PASS test under pressure