AU2024201110A1

AU2024201110A1 - Herbicide preparations and processes for manufacture thereof

Info

Publication number: AU2024201110A1
Application number: AU2024201110A
Authority: AU
Inventors: Hui Ming Zhang; Yi Xiang Zhang
Original assignee: Leadfarm Australia Pty Ltd
Current assignee: Leadfarm Australia Pty Ltd
Priority date: 2022-01-21
Filing date: 2024-02-21
Publication date: 2024-03-14
Also published as: AU2022200414A1

Abstract

HERBICIDE PREPARATIONS AND PROCESSES FOR MANUFACTURE THEREOF Abstract A herbicide preparation, comprising methabenzthiazuron at a concentration of at least 50 % (w/w); a surfactant; and water; is described, wherein the preparation is in the form of a dry flowable (DF) powder or water dispersible granules (WDGs) and has a suspension concentrate (SC) dispersibility of 80% or more. Processes for producing such preparations are also described.

Description

HERBICIDE PREPARATIONS AND PROCESSES FOR MANUFACTURE THEREOF CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional of Australian Patent Application No. 2022200414, the entire contents of which are incorporated herein by cross-reference.

FIELD OF THE INVENTION

The present invention relates generally to herbicides that are useful in, for example, pre- and post- emergence weed control of grass and broad-leaved crops such as rice, rape and legumes, and processes for their preparation. However, it will be appreciated that the invention is not limited to this particular field of use. In particular, the present invention relates to herbicides comprising methabenzthiazuron, and processes for their preparation.

BACKGROUND

Any discussion of the prior art throughout the specification should in no way be considered as an admission that such prior art is widely known or forms part of common general knowledge in the field.

Herbicides may come in different forms. One such form is water dispersible granules (WDGs), which are granular in appearance, contain 10-90% active ingredient and can be evenly dispersed in water for use. WDGs have the advantages of stable performance, low dust, good flowability, saving in packaging materials and costs, and convenience for transportation and storage. WDGs are also flexible in application and can be applied by a spraying method or soil mixing method.

Herbicide WDGs are generally prepared by a dry process, which mixes the active herbicidal ingredient(s), additive(s) and filler(s) with jet pulverisation or ultra-fine pulverisation to make a wettable powder mixture. Water is then added to knead it into a wet material, which is then granulated by disc granulation, extrusion granulation, high-speed shear granulation, fluidised bed granulation, or dry powder compression granulation (although other forms of granulation are known), and dried by fixed bed drying, boiling bed drying, fluidised bed drying, or other known forms of drying, to form the final WDG product.

Wettable powders (WPs) are dry, finely ground formulations that are mixed with water for application, where the powder particles settle out quickly. As WPs contain small particles, dust can be a problem, and material may need to be scooped for use as the powders are not generally pourable.

Dry flowable (DF) herbicides are a new type of solid preparation that were developed on the basis of WDGs, and are similar to WPs but are formulated as small granules that produce less dust than WPs. DFs are made using a wet sand milling process where the active herbicidal ingredient(s), additive(s) and filler(s) are ground into a slurry with a particle size of 5-15 tm, and then processed using pressure spray granulation before dehydration of the slurry to produce the DF. DFs are diluted in water prior to use.

Methabenzthiazuron is a substituted urea-uracil-based herbicide with the chemical name 1 (benzothiazol-2-yl)-1,3-dimethylurea, commonly called methabenzthiazuron (CAS No.: 18691-97-9). Its structure is depicted below:

-N N I`k S

Methabenzthiazuron achieves weed control by inhibiting the Hill reaction in plant photosynthetic crops. It is absorbed mainly through the roots of affected plants, and weeds die within 14-20 days of application. It is mainly used in overwintering cereal crops such as wheat, leguminous crops such as peas and onions, vegetables and other crops. Dosages of 15-22.5 g/100 m 2 for weed control in wheat fields and 14.3-28.5 g/100 m2 for weed control in bean fields may be used. Since methabenzthiazuron is mainly absorbed through the roots, the soil should be moist when applying. Methabenzthiazuron is not effective for weeds that reproduce via their root system and is not suitable for application to spring barley. However, methabenzthiazuron is safe for subsequent crops. Current commercially available methabenzthiazuron preparations containing methabenzthiazuron are in the form of WPs, which have poor suspension dispersibilities of 70% or lower and therefore effective concentrations of methabenzthiazuron of at most 70%. There is thus a need in the art for alternative herbicide formulations containing methabenzthiazuron.

Accordingly, there is a need for herbicidal preparations to overcome or ameliorate at least one of the disadvantages of the prior art, or which provide a useful alternative.

SUMMARY OF INVENTION

Described herein are WDG and DF herbicide preparations containing methabenzthiazuron as the active ingredient and processes of making them. In certain embodiments, the processes described herein produce methabenzthiazuron preparations in the form of WDGs and DFs having up to 85% methabenzthiazuron content. In certain embodiments, the suspension dispersion of the WDG and DF preparations described herein can reach 80% or more. Accordingly, WDG and DF herbicide preparations described herein may have excellent weed control effects.

As described herein, in some embodiments, fine granular products obtained by spray granulation are added to unsprayed slurries for kneading to obtain DF herbicide preparations with a large final particle size through use of rotary extrusion granulation or boiling granulation. Such preparations comprise finer microscopic particle sizes (D90 5-15 im) than WP and WDG preparations due to sand grinding, and therefore in some embodiments have better physical properties and/or superior biological activity, but also have larger final preparation particle sizes than WP and WDG preparations through use of a secondary granulation process, and therefore also advantageously have little or no dust drift. Accordingly, the processes and preparations described herein may, in some embodiments, protect the environment as well as operators. In some embodiments, the benefits may extend to ease of distribution, storage and transportation.

According to a first aspect of the invention there is provided a herbicide preparation, comprising: methabenzthiazuron at a concentration of at least 50 % (w/w); a surfactant; and water; wherein the preparation is in the form of a dry flowable (DF) powder or water dispersible granules (WDGs) and has a suspension concentrate (SC) dispersibility of 80% or more.

The following features may be used alone or in combination with the first aspect above. The herbicide preparation may comprise, in percentage by weight, from 50 to 85% of methabenzthiazuron, from 3.5 to 15.0% of the surfactant, and from 3 to 10% water. The herbicide preparation may further comprise an additive. The additive may be selected from a defoamer, a calcium and magnesium ion complexing agent, a binder, or a filler, or a combination of any two or more of these. The herbicide preparation may comprise a filler. The filler may be kaolin; light calcium carbonate; ammonium, potassium or sodium sulfate; diammonium, potassium or sodium hydrogen phosphate; ammonium, potassium or sodium chloride; ammonium, potassium, or sodium nitrate; corn starch; silica; sodium carbonate; sodium bicarbonate; or sodium tripolyphosphate; or a mixture of any two or more of these. The surfactant may be a polycarboxylate, a lignin sulfonate, an alkyl naphthalene sulfonate, an alkyl naphthalene sulfonate formaldehyde condensate, an alkylphenol polyoxyethylene polyoxypropylene ether, an ethylene oxide-propylene oxide block copolymer, a maleic acid acrylic acid copolymer, an alkyl sulfate, or an alkyl sulfonate, or a mixture of any two or more of these.

According to a second aspect of the invention there is provided a process for preparing a dry flowable (DF) herbicide preparation, said process comprising: grinding a mixture of methabenzthiazuron and a surfactant to produce a slurry; and spray drying the slurry to produce

a fine granular DF herbicide preparation; wherein the fine granular DF herbicide preparation comprises from 50 to 85% (w/w) methabenzthiazuron.

The following features may be used alone or in combination with the second aspect above.

The grinding may be performed using a sand mill. The process may further comprise combining the fine granular DF herbicide preparation with a slurry comprising a ground mixture of methabenzthiazuron and a surfactant to produce a granular mixture; and granulating

the granular mixture to produce a coarse or columnar DF herbicide preparation; wherein the coarse or columnar DF herbicide preparation comprises from 50 to 85% (w/w) methabenzthiazuron. The granulating may be performed using rotary extrusion to produce columnar DF particles or by boiling to produce coarse DF particles. The columnar DF particles may have a particle size of between 250-1680 im. The coarse DF particles have a particle size of between 250-710 im. The slurry combined with the fine granular DF herbicide preparation is the slurry of the second aspect.

According to a third aspect of the invention there is provided a process for preparing a water dispersible granule (WDG) herbicide preparation, said process comprising: jet pulverising or ultra-fine pulverising a mixture of methabenzthiazuron and a surfactant, thereby forming a

wettable powder; adding water to the wettable powder to produce a wet material; granulating

the wet material by rotary extrusion to produce columnar granules; and drying the columnar granules to produce a WDG herbicide preparation; wherein the WDG herbicide preparation comprises from 50 to 85% (w/w) methabenzthiazuron.

The following features may be used alone or in combination with the second or third aspects above.

An additive may be added to the mixture of methabenzthiazuron and surfactant. The additive may be selected from a defoamer, a calcium and magnesium ion complexing agent, a binder, or a filler, or a combination of any two or more of these. The additive may be a filler. The filler may be kaolin; light calcium carbonate; ammonium, potassium or sodium sulfate; diammonium, potassium or sodium hydrogen phosphate; ammonium, potassium or sodium chloride; ammonium, potassium, or sodium nitrate; corn starch; silica; sodium carbonate; sodium bicarbonate; or sodium tripolyphosphate; or a mixture of any two or more of these. The surfactant may be a polycarboxylate, a lignin sulfonate, an alkyl naphthalene sulfonate, an alkyl naphthalene sulfonate formaldehyde condensate, an alkylphenol polyoxyethylene polyoxypropylene ether, an ethylene oxide-propylene oxide block copolymer, a maleic acid acrylic acid copolymer, an alkyl sulfate, or an alkyl sulfonate, or a mixture of any two or more of these. The DF herbicide preparation or WDG herbicide preparation may have a suspension concentrate (SC) dispersibility of 80% or more. The DF herbicide preparation or WDG herbicide preparation may comprise water. The DF herbicide preparation or WDG herbicide preparation may comprise, in percentage by weight, from 50 to 85% of methabenzthiazuron, from 3.5 to 15.0% of surfactant, and from 3 to 10% water.

According to a fourth aspect of the invention there is provided the process of the second or third aspect above when used to produce a herbicidal preparation according to the first aspect above.

According to a fifth aspect of the invention there is provided a herbicidal preparation produced by the process of the second or third aspect above.

According to a sixth aspect of the invention there is provided a use of a herbicidal preparation according to the first aspect above or a herbicidal preparation produced by the process of the second or third aspect above for killing weeds.

DEFINITIONS

In describing and claiming the present invention, the following terminology will be used in accordance with the definitions set out below. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments of the invention only and is not intended to be limiting. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one having ordinary skill in the art to which the invention pertains.

Unless the context clearly requires otherwise, throughout the description and the claims, the words "comprise", "comprising", and the like are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense; that is to say, in the sense of "including, but not limited to".

Other than in the operating examples, or where otherwise indicated, all numbers expressing quantities of ingredients or reaction conditions used herein are to be understood as modified in all instances by the term "about".

In what follows, unless otherwise indicated, "%" will mean "weight %" and "ratio" will mean "weight ratio". As used herein, the term "weight %" or "wt%" is calculated as [100 x mx/mtot], where mx is the mass of component x and mtot is the total mass of all components. For the avoidance of doubt, all (w/w) values used herein refer to % (w/w) in the final (dried) DF or WDG product unless the context clearly suggests otherwise.

The term "substantially" as used herein shall mean comprising more than 50% by weight, where relevant, unless otherwise indicated.

The recitation of a numerical range using endpoints includes the endpoints and all numbers subsumed within that range (e.g., from I to 10 includes 1, 1.5, 2, 5, 5.75, 7.1, 8.5, 9, 10, etc.).

The terms "preferred" and "preferably" refer to embodiments of the invention that may afford certain benefits, under certain circumstances. However, other embodiments may also be preferred under the same or other circumstances. Furthermore, the recitation of one or more preferred embodiments does not imply that other embodiments are not useful and is not intended to exclude other embodiments from the scope of the invention.

As used herein and in the claims, the singular form of "a", "an", and "the" may include the plural referents unless the context clearly dictates otherwise.

As used herein, the terms "about" and "approximately" are used synonymously. Both terms are meant to cover any normal fluctuations or variations understood by those skilled in the art. In some embodiments, "about" and "approximately" refer to 10% of the reference value, or ±5%, or 2%, or 1%, or 0.1% of the reference value.

In this application, the use of "or" means "and/or" unless stated otherwise.

DETAILED DESCRIPTION

The skilled addressee will understand that the invention comprises the embodiments and features disclosed herein as well as all combinations and/or permutations of the disclosed embodiments and features.

Described herein is a herbicide preparation, comprising: methabenzthiazuron at a concentration of at least 50 % (w/w); a surfactant; and water; wherein the preparation is in the form of a dry

flowable (DF) powder or water dispersible granules (WDGs) and has a suspension concentrate (SC) dispersibility of 80% or more. Also described herein is a process of preparing WDG or DF herbicide preparations.

Methabenzthiazuron

The preparations described herein comprise methabenzthiazuron. In some embodiments, the preparations comprise from 50 to 85% (w/w) of methabenzthiazuron, or from 50 to 75%, or from 60 to 85%, or from 75 to 85%, or from 70 to 85% methabenzthiazuron, or may comprise at least 50%, or at least 55%, or at least 60%, or at least 65%, or at least 70%, or at least 7 5 %, or at least 80%, or at least 85% methabenzthiazuron, or may comprise 50%, 55%, 60%, 65%, 7 0% , 7 5%, 8 0%, or 8 5% (w/w) 50% methabenzthiazuron. Commercial sources of methabenzthiazuron will be known to those of skill in the art, but may include Sigma Aldrich. The methabenzthiazuron used may have any suitable purity, and in one embodiment, has a purity of 96.2%.

Surfactant

The preparations described herein comprise a surfactant. In some embodiments, the surfactant comprises a single surfactant. In other embodiments, the surfactant comprises a mixture of two different surfactants. In yet further embodiments, the surfactant comprises a mixture of two or more different surfactants. In such embodiments, the two or more surfactants may be present in equal amounts or may be present in different amounts. In embodiments where two or more surfactants are used, the surfactants may be used in any suitable ratio by mass. In one embodiment, a suitable ratio by mass when two surfactants are used may be from 1:1 to 5:1, or from 1:1 to 2.5:1, or from 2.5:1 to 5:1, or from 1.5:1 to 3:1, or may be 1:1, 1.5:1, 2.0:1, 2.5:1, 3:1, 3.5:1, 4:1, 4.5:1 or 5:1. In other embodiments, three surfactants may be used in any suitable ratio by mass. In one embodiment, the suitable ratio by mass when three surfactants are used may be 2:1:1 or 5:2:1. In some embodiments, the preparations herein comprise from I to 20% (w/w) surfactant, or from I to 15%, or from 2 to 20%, or from 3 to 15%, or from 5 to 18%, or from 4 to 13%, or from 8 to 14%, or from 3.5 to 15%, or comprise 1, 2, 3, 3.5, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 or 20% surfactant. In certain embodiments, the surfactant is selected from a polycarboxylate, a lignin sulfonate, an alkyl naphthalene sulfonate, an alkyl naphthalene sulfonate formaldehyde condensate, an alkylphenol polyoxyethylene polyoxypropylene ether, an ethylene oxide-propylene oxide block copolymer, a maleic acid acrylic acid copolymer, an alkyl sulfate or an alkyl sulfonate. In another embodiment, the surfactant comprises a mixture of alkyl naphthalene sulfonic acid formaldehyde and alkyl naphthalene sulfonate. In another embodiment, the surfactant comprises a mixture of alkyl naphthalene sulfonic acid formaldehyde and alkyl naphthalene sulfonate. In one embodiment, the surfactant is alkylphenol polyoxyethylene polyoxypropylene ether. In one embodiment, the surfactant comprises a mixture of maleic acid-acrylic acid copolymer, alkyl naphthalene sulfonate, and alkylphenol polyoxyethylene polyoxypropylene ether. In a further embodiment, the surfactant comprises a mixture of polycarboxylate, lignin sulfonate, and alkylphenol polyoxyethylene polyoxypropylene ether.

Water

The preparations described herein comprise water. In some embodiments, the preparations herein comprise from I to 15% (w/w) water, or from Ito 10%, or from 2 to 12%, or from 3 to 10%, or from 5 to 15%, or from 6 to 13%, or from 8 to 14%, or comprise 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14 or 15% water, or greater than 0% water but less than 10%, less than 9 %,

less than 8%, less than 7 .5%, less than 6%, or less than 5% water. In certain embodiments, the preparations described herein contain water in an amount suitable to maintain the suspension concentration (SC) dispersibility at more than 75%, or more than 80%, or more than 85%, or more than 90%. Methods for determining SC dispersibility are described below. In some embodiments, this amount is from 1 to 15%, or from 3 to 10% water (w/w). Without wishing to be bound by theory, it is hypothesised that the S atom on the thiazole heterocyclic ring of methabenzthiazuron forms a hydrate when it contacts water, which can cause coagulation and sedimentation of methabenzthiazuron-containing herbicide products. The present inventors have discovered that inclusion of water in the herbicide preparations disclosed herein may overcome these issues.

Additives

The preparations described herein may comprise one or more additives. In certain embodiments, the additives may include a defoamer, a calcium and magnesium ion complexing agent, or a binder. In some embodiments, the additive comprises a mixture of a defoamer and a binder. In other embodiments, the additive comprises a mixture of a defoamer and a calcium and magnesium ion complexing agent. In other embodiments, the additive comprises a mixture of a binder and a calcium and magnesium ion complexing agent. In one embodiment, the additive is a defoamer. In one embodiment, the additive is a calcium and magnesium ion complexing agent. In another embodiment, the additive is a binder. Suitable defoamers, calcium and magnesium ion complexing agents, and binders for use in the preparations herein will be known to those of skill in the art. Suitable defoamers can include but are not limited to, for example, tallow fatty acid salt. Calcium and magnesium ion complexing agents can include but are not limited to for example, EDTA sodium salt. Binders may include but are not limited to, for example, alkyl organosilicon, polyvinyl alcohol and soluble starch. In other embodiments, the additive may be an inert material or filler. Additives as described in this section may be included in the preparations described herein as modifiers to improve the performance of the preparation or to assist with chemical balancing.

In one embodiment, the preparation described herein comprises a filler. In certain embodiments, the filler comprises one or more of the following: kaolin, light calcium carbonate, a sulfate salt, a hydrogen phosphate salt, a chloride salt, a nitrate, corn starch, silica, sodium carbonate, sodium bicarbonate or sodium tripolyphosphate. The sulfate salt may be selected from ammonium sulfate, potassium sulfate, and sodium sulfate. The hydrogen phosphate salt may be diammonium hydrogen phosphate, potassium hydrogen phosphate, or sodium hydrogen phosphate. The chloride salt may be ammonium chloride, potassium chloride or sodium chloride. The nitrate salt may be ammonium nitrate, potassium nitrate or sodium nitrate. In one embodiment, the filler is sodium sulfate. In another embodiment, the filler is a mixture of sodium sulfate and kaolin. In another embodiment, the filler is a mixture of sodium sulfate and corn starch. Suitable commercial sources of fillers as described herein will be known to those of skill in the art.

In one embodiment, the additive present in the preparations described herein may comprise a mixture of a defoamer, a calcium and magnesium ion complexing agent, a binder and/or a filler. In one embodiment, the additive present in the preparations described herein may comprise a mixture of sodium sulfate, corn starch and a complexing agent. In one embodiment, the additive present in the preparations described herein may comprise a mixture of sodium sulfate, corn starch, defoamer, and a complexing agent.

Herbicide preparations

In certain embodiments, the preparations described herein refer to DFs or WDGs prior to dilution with water for use. Accordingly, in some embodiments, the preparations described herein are DF or WDG concentrates.

The general requirements for herbicide DFs are shown in Table 1 below. As used herein, the terms "fine granular product" and "fine particles" refers to particles having a size of between 105-250 gm as outlined in Table 1. As used herein, the term "coarse particles" refers to particles having a size of between 250-710 pm as outlined in Table 1. As used herein, the term "columnar particles" refers to particles having a size of between 250-1680 pm as outlined in Table 1.

Table 1: General requirements for herbicide DFs Indicator name Standard Measurement value Active ingredient, %,w/w 50.0-85.0 High performance liquid chromatography extemal standard (HPLC) (*XXX/WG/(M)/3) Suspension rate, %,w/w,; 75 CIPAC MT168 Wetting time, S, < 60 CIPAC MT53.3.2 (dynamic)

Fineness (after disintegration),%,> 98 Wet sieve method (through 0.043mm pore size) CIPAC MT185 Weight loss on drying, %,w/w, < 3-10 CIPAC MT30,1 (with hydrophilic water)

Appearance Fine particles 80 105-250 m particle size, pm, Coarse particles 90 250-710 pm [mesh 24-60] %, w/w Columnar 95 250-1680 sm [mesh 12-60] PH value suspensioni) 4-7.5 pH meter method CIPAC MT75

Storage stability Qualified Qualified after 14 days at 54± C

The preparations described herein have a suspension concentrate (SC) dispersibility of 80% or more. SC dispersibility may be measured by any suitable means known in the art, but may in some embodiments be measured using the Collaborative International Pesticides Analytical Council (CIPAC)method MT168, which is well known to the person of skill in the art. In one embodiment, the SC dispersibility of preparations as described herein is 75% or more, or 80% or more, or 85% or more, or 90% or more, or is from 75% to 95%, or is from 80% to 90%, or is from 85% to 95%, or is from 75% to 85%, or is 75%, 80%, 85%, 90%, 93% or 95%.

Processes

Processes of preparing a DF preparation comprising methabenzthiazuron may comprise the following steps: adding methabenzthiazuron TC, surfactant, filler and water into a sand mill, and grinding the mixture into slurry of D90 5-15 tm. To obtain a fine DF powder comprising methabenzthiazuron the slurry is then spray granulated at 70-85 °C in a centrifugal spray dryer. The fine granular product obtained by spray granulation is then added to the unsprayed slurry for kneading, and then rotary extrusion granulated or boiling granulated to obtain a DF of larger particle size appearance.

Processes of preparing a WDG preparation comprising methabenzthiazuron may comprise the following steps: mixing methabenzthiazuron TC, surfactant and filler evenly, crushing the material to 10-25 pm in a jet pulverizer, adding 20-30% water to knead it into a wet material, then extruding it into granules in a rotary granulator, and drying at 45 °C. The final step is sieving the granules to remove any fine powder to obtain methabenzthiazuron as WDGs.

As described herein, a process for preparing a dry flowable (DF) herbicide preparation may comprise grinding a mixture of methabenzthiazuron and a surfactant to produce a slurry, optionally using a sand mill; and spray drying the slurry to produce afine granular DF herbicide preparation; wherein the fine granular DF herbicide preparation comprises from 50 to 85% (w/w) methabenzthiazuron. The process described herein may further comprise combining the fine granular DF herbicide preparation with a slurry comprising a ground mixture of methabenzthiazuron and a surfactant to produce a granular mixture; and granulating the granular mixture to produce a coarse or columnar DF herbicide preparation; wherein the coarse or columnar DF herbicide preparation comprises from 50 to 85% (w/w) methabenzthiazuron. It will be understood that in some embodiments, a single slurry is manufactured (comprising a surfactant as described herein, water, methabenzthiazuron, and optionally one or more additives) and that this slurry is divided into a "slurry" portion and a "spray dried" portion, where the "spray dried" portion is spray dried to produce a fine granular DF herbicide preparation, and it is these two portions that are combined together to produce the coarse or columnar DF herbicide preparation. In will be understood that in some embodiments, two (or more) separate slurries will be produced, because one portion is entirely converted by spray drying into a spray dried fine granular DF herbicide preparation and/or because a mixture of different surfactants and/or additives is desired in the final coarse or columnar DF herbicide preparation, and accordingly, that any spray dried fine granular DF herbicide preparation produced by a process as described herein may be combined with any slurry comprising methabenzthiazuron and a surfactant as described herein to produce a coarse or columnar DF herbicide preparation and be within the scope of the present invention. Accordingly, in some embodiments, the slurry used to make the fine granular DF herbicide preparation may be identical in composition to the slurry used to make the coarse or columnar DF herbicide preparation. In other embodiments, the slurry used to make the fine granular DF herbicide preparation and the slurry used to make the coarse or columnar DF herbicide preparation differ in the type and/or amount of surfactant (or mixtures thereof), and/or in the amount of methabenzthiazuron, and/or in the type and/or amount of additive used.

Methods of grinding mixtures will be known to one of skill in the art. In certain embodiments, grinding is performed using a sand mill. In some embodiments, granulating is performed using rotary extrusion to produce columnar DF particles or by boiling to produce coarse DF particles. Also described herein is a process for preparing a water dispersible granule (WDG) herbicide preparation, said process comprising: jet pulverising or ultra-fine pulverising a mixture of methabenzthiazuron and a surfactant, thereby forming a wettable powder; adding water to the wettable powder to produce a wet material; granulating the wet material by rotary extrusion to produce columnar granules; and drying the columnar granules to produce a WDG herbicide preparation; wherein the WDG herbicide preparation comprises from 50 to 85% (w/w) methabenzthiazuron. Columnar granules are understood by those in the art to refer to granules having a column-like appearance; that is, having a pillar or cylindrical shape or appearance.

EXAMPLES

The present invention will now be described with reference to the following examples which should be considered in all respects as illustrative and non-restrictive.

Example 1: Preparation of herbicides

Embodiment 1: Preparation of fine particles of 50% methabenzthiazuron DF

Weigh 104.Og of 96.2% methabenzthiazuron TC (Fivestar (Nantong) Chemical Co., Ltd), 25g of alkyl naphthalene sulfonic acid formaldehyde condensate (Dispersant NNO; Nami (Thailand) Co., Ltd.), 1O.Og of alkyl naphthalene sulfonate (SP-2888; Jiangsu Qingyu),1O.Og of sodium sulfate, 1.Og of defoamer (FLP; Shanghai Lansheng), 2g of binder (PVA1788; SINOPEC Shanghai), 37.g of kaolin and 200g of water, mix them well, and add the mixture to the sand mill, and then grind the material to a D90 5-15 pm slurry. 370g of the slurry was spray dried in a centrifugal spray dryer at 70-85 °C to obtain 50% methabenzthiazuron DF fine particles (about 200g).

Embodiment 2: Preparation of coarse particles of 50% methylphenothiazuron DF

Take 75g of fine particles prepared in Embodiment 1, add them into the boiling granulator, and make the material boiling; spray 13.5g of slurry prepared in Embodiment 1 slowly into the boiling granulator, and after spraying, dry the wet particles in the boiling dryer at 45°C or less until the moisture is less than 10%, and then sieve to get 24-60 mesh particles to make 50% methabenzthiazuron DF coarse particles.

Embodiment Example 3: Preparation of columnar particles of 50% methabenzthiazuron DF

Take 60g of fine particles prepared in Embodiment 1, and add 16.5g slurry prepared in Embodiment 1 together in the kneader to knead them into wet material; extrusion granulate with D1 mm aperture rotary granulator, and dry the wet particles in the boiling dryer at 45°C until the moisture is less than 6%, and then sieve to get 12-60 mesh particles to make 50% methabenzthiazuron DF agent columnar particles.

Embodiment 4: Preparation of 50% methabenzthiazuron WDG

Weigh 52.Og of 96.2% methabenzthiazuron TC (Fivestar (Nantong) Chemical Co., Ltd), 12.5g of alkyl naphthalene sulfonic acid formaldehyde condensate (Dispersant NNO; Nami (Thailand) Co., Ltd.), 5.g of alkyl naphthalene sulfonate (SP-2888; Jiangsu Qingyu), 5.g of sodium sulfate, 0.5g of defoamer (FLP; Shanghai Lansheng), Ig of binder (PVA1788; SINOPEC Shanghai) and 18.5g of kaolin, mix them well, and crush the mixture in the jet pulverizer to a particle size of 15-25 pm ultra-fine powder; add the powder into the kneader, and add about 22g of water to knead the mixture into wet material; extrusion granulate with

D1 mm aperture rotary granulator, and dry the wet granules in the boiling dryer at 45°C to less than 6% moisture, and then sieve to get 12-60 mesh particles to make about 100g 50% methylbenzthiazuron WDG, with the appearance of D1 mm columnar particles.

Embodiment 5: Preparation of fine particles of 70% methabenzthiazuron DF

Weigh 145.5g of 96.2% methabenzthiazuron TC (Fivestar (Nantong) Chemical Co., Ltd), 10.0g of maleic acid-acrylic acid copolymer (LAS-70; Jiangsu Qingting), 5.Og of alkyl naphthalene sulfonate (SP-2888; Jiangsu Qingyu), 5.Og of alkylphenol polyoxyethylene polyoxypropylene ether (NPE-108; Jiangsu Haian Petroleum Chemical Factory), 5.Og of corn starch, 1.Og of defoamer (FLP; Shanghai Lansheng), 1g of complexing agent (EDTA), 13.Og of sodium sulfate and 200g of water, mix them well, and add the mixture into sand mill, and then grind the material to D90 5-15pm slurry. 370g of slurry was spray dried in a centrifugal spray dryer at 70-85°C to obtain 70% methylbenzthiazuron DF fine particles (about 200g).

Embodiment 6: Preparation of coarse particles of 70% methylphenothiazuron DF

Take 75g of fine particles prepared in Embodiment 5, add them into the boiling granulator, and make the material boiling; spray 13.5g of slurry prepared in Embodiment 5 slowly into the boiling granulator, and after spraying, dry the wet particles in the dryer at 45°C or less until the moisture is less than 7 .5%, and then sieve to get 24-60 mesh particles to make 70

% methabenzthiazuron DF coarse particles.

Embodiment 7: Preparation of columnar particles of 70% methabenzthiazuron DF

Take 60g of fine particles prepared in Embodiment 5, and add 16.5g slurry prepared in Embodiment 1 together in the kneader to knead them into wet material; extrusion granulate with D1 mm aperture rotary granulator, and dry the wet particles in the boiling dryer at 45°C until the moisture is less than 7.5%, and then sieve to get 12-60 mesh particles to make 70% methabenzthiazuron DF agent columnar particles.

Embodiment 8: Preparation of 70% methabenzthiazuron WDG

Weigh 72.7g of 96.2% methabenzthiazuron TC (Fivestar (Nantong) Chemical Co., Ltd), 5.0g of maleic acid-acrylic acid copolymer (LAS-70; Jiangsu Qingting), 2.5g of alkyl naphthalene sulfonate (SP-2888; Jiangsu Qingyu), 2.5g of alkylphenol polyoxyethylene polyoxypropylene ether (NPE-108; Jiangsu Haian Petroleum Chemical Factory), 2.5g of corn starch, 0.5g of defoamer (FLP; Shanghai Lansheng), 0.5g of complexing agent (EDTA) and 6.5g of sodium sulfate, mix them well, and crush the mixture in the jet pulverizer to a particle size of 15-25 pm ultrafine powder; add the powder into the kneader, and add about 25g of water to knead the mixture into wet material; extrusion granulate with D1 mm aperture rotary granulator, and dry the wet granules in the boiling dryer at 45°C to less than 7 .5% moisture, and then sieve to get 12-60 mesh particles to make 70% methyl benzothiazuron WDG (about 100g), with the appearance of D1 mm columnar particles.

Embodiment 9: Preparation of fine particles of 85% methabenzthiazuron DF

Weigh 176.7g of 96.2% methabenzthiazuron TC (Fivestar (Nantong) Chemical Co., Ltd), 5.0g of polycarboxylate (GY-DF85; Beijing Guangyuan Yinong), 2.0g of lignin sulfonate (REAX

85A, REAX 910; Meadwestvaco), 1.0g of alkylphenol polyoxyethylene polyoxypropylene ether (NPE-108; Jiangsu Haian Petroleum Chemical Factory) and 200g of water, mix them well, and add the mixture into sand mill, and then grind the material to D90 5-15 pm slurry. 370g of slurry was spray dried in a centrifugal spray dryer at 70-85°C to obtain 85% methylbenzthiazuron DF fine particles (about 200g).

Embodiment 10: Preparation of coarse particles of 85% Methabenzthiazuron DF

Take 75g of fine particles prepared in Embodiment 9, add them into the boiling granulator, and make the material boiling; spray 13.5g of slurry prepared in Embodiment 9 slowly into the boiling granulator, and after spraying, dry the wet particles in the dryer at 45°C or less until the moisture is less than 8%, and then sieve to get 24-60 mesh particles to make 85% methabenzthiazuron DF coarse particles.

Embodiment 11: Preparation of columnar particles of 85% methabenzthiazuron DF

Take 60g of fine particles prepared in Embodiment 9, and add 16.5g slurry prepared in Embodiment 9 together in the kneader to knead them into wet material; extrusion granulate with D1 mm aperture rotary granulator, and dry the wet particles in the boiling dryer at 45°C until the moisture is less than 5%, and then sieve to get 12-60 mesh particles to make 85% methabenzthiazuron DF agent columnar particles.

Embodiment 12: Preparation of 85% methabenzthiazuron WDG

Weigh 88.3g of 96.2% methabenzthiazuron TC (Fivestar (Nantong) Chemical Co., Ltd), 2.5g of polycarboxylate (GY-DF85; Beijing Guangyuan Yinong), 1.0g of lignin sulfonate (REAX 85A, REAX 910; Meadwestvaco) and 0.5g of alkylphenol polyoxyethylene polyoxypropylene ether (NPE-108; Jiangsu Haian Petroleum Chemical Factory), mix them well, and crush the mixture in the jet pulverizer to a particle size of 15-25 pm ultrafine powder; add the powder into the kneader, and add about 25g of water to knead the mixture into wet material; extrusion granulate with D1 mm aperture rotary granulator, and dry the wet granules in the boiling dryer at 45°C to less than 7 .5% moisture, and then sieve to get 12-60 mesh particles to make 85% methyl benzothiazuron WDG (about 100g), with the appearance of D1 mm columnar particles.

The relevant performance indicators of methabenzthiazuron WDG and DF made in each embodiment were tested and the results met the industry technical requirements. These indicators are also compared with commercially available 70% methabenzthiazuron wettable powder, and the results are shown in Table 2 below:

Table 2 Indicators

00

E 50-85 75 60 98 3-10 Q 4-7.5 Q

1 50% DF S 50.04 93.2 10 Q 5.21 Q 5.8 Q

2 50%r/ DF B 50.22 92.4 16 Q 4.89 Q 5.7 Q

3 50% DF E 50.24 89.7 30 Q 5.01 Q 5.8 Q

4 50% WDG E 49.88 87.7 34 Q 5.22 Q 5.4 Q

5 70% DF S 69.87 91.3 14 Q 6.89 Q 5.3 Q

6 70% DF B 70.32 88.4 21 Q 6.47 Q 5.1 Q

7 70% DF E 70.08 89.2 30 Q 7.01 Q 5.2 Q

8 70% WDG E 70.02 88.4 33 Q 6.98 Q 5.6 Q

9 85% DF S 85.02 87,6 15 Q 8,21 Q 4.9 Q

10 85% DF B 84.77 87.2 22 Q 8.33 Q 5.1 Q

11 85% DF E 84.97 86.4 38 Q 8.06 Q 5.0 Q

12 85% WDG E 85.04 85.8 37 Q 8.24 Q 4.3 Q

N/A* 70% WP 70.33 64.2 41 Q 2.43 Q 4.6 U

Spray - S; Boiling - B; Extrusion - E High performance liquid chromatography extemal standard (HPLC) (*XXX/WG/(M)/3) CIPAC MT168 4 CIPAC MT53.3.2 (dynamic) After disintegration:Q = qualified. Wet sieve method (through 0.043mm pore size) CIPAC MT85. CIPAC MT30.I(including hydrophilic water) Sieving method; Q = qualified pH meter method CIPAC MT75 Q after 14 days at 5441°C; Q = qualified; U = unqualified *Commercially available formulation

The specific embodiments described above are only the preferred embodiments of the present invention. It should be pointed out that, for those of ordinary skill in the technical field, without departing from the principles of the present invention, several improvements or substitutions can be made, and these improvements or substitutions should also be regarded as the protection scope of the present invention.

The reference in this specification to any prior publication (or information derived from it), or to any matter which is known, is not, and should not be taken as an acknowledgment or admission or any form of suggestion that that prior publication (or information derived from it) or known matter forms part of the common general knowledge in the field of endeavour to which this specification relates.

Claims

1. A herbicide preparation, comprising: methabenzthiazuron at a concentration of at least 50% (w/w); a surfactant; and water; wherein the preparation is in the form of a dry flowable (DF) powder or water dispersible granules (WDGs) and has a suspension concentrate (SC) dispersibility of 80% or more.

2. The herbicide preparation of claim 1, comprising from 50% (w/w) to 85% (w/w) of methabenzthiazuron, from 3.5% (w/w) to 15.0% (w/w) of the surfactant, and from 3% (w/w) to % (w/w) water.

3. The herbicide preparation of claim 1 or claim 2, further comprising an additive selected from a defoamer, a calcium and magnesium ion complexing agent, a binder, or a filler, or a combination of any two or more of these.

4. The herbicide preparation of claim 3, wherein the additive is a filler and the filler is kaolin; light calcium carbonate; ammonium, potassium or sodium sulfate; diammonium, potassium or sodium hydrogen phosphate; ammonium, potassium or sodium chloride; ammonium, potassium, or sodium nitrate; corn starch; silica; sodium carbonate; sodium bicarbonate; or sodium tripolyphosphate; or a mixture of any two or more of these.

5. The herbicide preparation of any one of claims 1 to 4, wherein the surfactant is a polycarboxylate, a lignin sulfonate, an alkyl naphthalene sulfonate, an alkyl naphthalene sulfonate formaldehyde condensate, an alkylphenol polyoxyethylene polyoxypropylene ether, an ethylene oxide-propylene oxide block copolymer, a maleic acid - acrylic acid copolymer, an alkyl sulfate, or an alkyl sulfonate, or a mixture of any two or more of these.

6. A process for preparing a dry flowable (DF) herbicide preparation, said process comprising: grinding a mixture of methabenzthiazuron and a surfactant to produce a slurry; and spray drying the slurry to produce a fine granular DF herbicide preparation; wherein the fine granular DF herbicide preparation comprises from 50 to 85% (w/w) methabenzthiazuron.

7. The process of claim 6, wherein grinding is performed using a sand mill.

8. The process of claim 6 or claim 7, further comprising: combining the fine granular DF herbicide preparation with a slurry comprising a ground mixture of methabenzthiazuron and a surfactant to produce a granular mixture; and granulating the granular mixture to produce a coarse or columnar DF herbicide preparation; wherein the coarse or columnar DF herbicide preparation comprises from 50% to 85% (w/w) methabenzthiazuron.

9. The process of claim 8, wherein the granulating is performed using rotary extrusion to produce columnar DF particles or by boiling to produce coarse DF particles.

10. The process of claim 9, wherein the columnar DF particles have a particle size of between 250-1680 m or the coarse DF particles have a particle size of between 250-710 m.

11. The process of any one of claims 8 to 10, wherein the slurry combined with the fine granular DF herbicide preparation is the slurry of claim 6.

12. A process for preparing a water dispersible granule (WDG) herbicide preparation, said process comprising: jet pulverising or ultra-fine pulverising a mixture of methabenzthiazuron and a surfactant, thereby forming a wettable powder; adding water to the wettable powder to produce a wet material; granulating the wet material by rotary extrusion to produce columnar granules; and drying the columnar granules to produce a WDG herbicide preparation; wherein the WDG herbicide preparation comprises from 50% to 85% (w/w) methabenzthiazuron.

13. The process of any one of claims 6 to 12, wherein an additive as described in claim 3 or claim 4 is added to the mixture of methabenzthiazuron and surfactant.

14. The process of any one of claims 6 to 13, wherein the surfactant is a polycarboxylate, a lignin sulfonate, an alkyl naphthalene sulfonate, an alkyl naphthalene sulfonate formaldehyde condensate, an alkylphenol polyoxyethylene polyoxypropylene ether, an ethylene oxidepropylene oxide block copolymer, a maleic acid - acrylic acid copolymer, an alkyl sulfate, or an alkyl sulfonate, or a mixture of any two or more of these.

15. The process of any one of claims 6 to 14, wherein the DF herbicide preparation or WDG herbicide preparation has a suspension concentrate (SC) dispersibility of 80% or more.

16. The process of any one of claims 6 to 15, wherein the DF herbicide preparation or WDG herbicide preparation comprises water.

17. The process of any one of claims 6 to 16, wherein the DF herbicide preparation or WDG herbicide preparation comprises from 50% (w/w) to 85% (w/w) of methabenzthiazuron, from 3.5% (w/w) to 15.0% (w/w) of surfactant, and from 3% (w/w) to 10% (w/w)water.

18. The process of any one of claims 6 to 17 when used to produce a herbicidal preparation according to any one of claims I to 5.

19. An herbicidal preparation produced by the process of any one of claims 6 to 18.

20. Use of an herbicidal preparation according to any one of claims 1 to 5, or a herbicidal preparation produced by the process of any one of claims 6 to 17, for killing weeds.