FORM 2
THE PATENTS ACT, 1970
(39 OF 1970)
COMPLETE SPECIFICATION
(See Section 10)
A PROCESS FOR PREPARING CHEMICALLY STABLE, WATER DISPERSIBLE GRANULES OF HERBICIDES.
UNITED PHOSPHORUS LIMITED, a company incorporated under the Companies Act, 1956 having its registered office at 3-11, GIDC, Vapi-396 195, State of Gujarat, India and its corporate office at Uniphos House, 11th Road, C. D. Marg, Khar (West), Mumbai - 400 052, State of Maharashtra, India an Indian Company.
The following specification particularly describes the nature of this invention and the manner in which it is to be performed:

Field of Invention
The present invention relates to a novel process for preparing chemically stable, non-dusty, spherical, water dispersible granules of Herbicides.
Background and Prior Art:
In recent years, agricultural chemicals are most preferably formulated in the form of dusts, wettable powders, soluble powders, emulsifiable concentrates, soluble liquid/concentrates, granules, coated granules, water dispersible granules, suspension concentrates, solution.
Wettable powders are preparations which are uniformly dispersible in water and which, besides the active compound, also comprise ionic and/or nonionic surfactants (wetting agents, dispersants), for example polyethoxylated alkylphenols, polyethoxylated fatty alcohols, polyethoxylated fatty amines, fatty alcohol polyglycol ether sulfates, alkanesulfonates, alkylbenzenesulfonates, sodium lignosulfonate, sodium 2,2'-dinaphthylmethane-6,6'-disulfonate, sodium dibutyinaphthalenesulfonate or else sodium oleoylmethyltaurinate, in addition to a diluent or inert substance. To prepare the wettable powders, the herbicidally active compounds are ground finely, for example in customary equipment such as hammer mills, blower mills and air-jet mills, and simultaneously or subsequently mixed with the formulation auxiliaries.
The active compound concentration in wettable powders is, for example, approximately 10 to 90% by weight, the remainder to 100% by weight being composed of customary formulation components.
Emulsifiable concentrates are prepared by dissolving the active compound in an organic solvent, for example butanol, cyclohexanone, dimethylformamide, xylene, or else higher-boiling aromatics or hydrocarbons or mixtures of the organic solvents with the addition of one or more ionic and/or nonionic surfactants (emulsifiers). Examples of emulsifiers which can be used are: calcium salts of alkylarylsulfonic acids such as calcium dodecylbenzenesulfonate, or nonionic emulsifiers such as fatty acid polyglycol esters, alkylaryl polyglycol ethers, fatty alcohol polyglycol ethers, propylene oxide/ethylene oxide condensates, alkyl polyethers, sorbitan esters, for example sorbitan fatty acid esters or polyoxyethylene sorbitan esters, for example polyoxyethylene sorbitan fatty acid esters.
In the case of emulsifiable concentrates, the active compound concentration may amount to approximately 1 to 90, preferably 5 to 80, % by weight.
Dusts are obtained by grinding the active compound with finely divided solid substances, for example talc, natural clays such as kaolin, bentonite and pyrophyllite, or diatomaceous earth.

Formulations in the form of dusts comprise 1 to 30% by weight of active compound, in most cases preferably 5 to 20% by weight of active compound.
Suspension concentrates can be water or oil-based. They can be prepared, for example, by wet grinding using commercially available bead mills with an optional addition of surfactants as already mentioned above for example in the case of the other types of formulation.
And sprayable solutions comprise approximately 0.05 to 80, preferably 2 to 50, % by weight of active compound.
Emulsions, for example oil-in-water emulsions (EW), can be prepared for example by means of stirrers, colloid mills and/or static mixers using aqueous organic solvents and, if appropriate, surfactants as already mentioned above for example in the case of the other types of formulation.
Granules can be prepared either by spraying the active compound onto adsorptive granulated inert material or by applying active compound concentrates to the surface of carriers such as sand, kaolinites or of granulated inert material by means of binders, for example polyvinyl alcohol, sodium polyacrylate or else mineral oils. Suitable active compounds can also be granulated in the manner, which is conventional for the production of fertilizer granules, if desired as a mixture with fertilizers.
Water-dispersible granules are generally prepared by the customary processes such as spray drying, fluidized-bed granulation, disk granulation, mixing with high-speed mixers and extrusion without solid surfactant, binder, disintegrating agent, stabilizer and inert material.
The active compound content of water-dispersible granules depends partly on whether the active compound is in liquid or solid form and on which granulation auxiliaries, fillers and the like are being used. The active compound content of the water-dispersible granules amounts to, for example, between 1 and 95% by weight, preferably between 10 and 80% by weight.
In addition, the abovementioned formulations of active compounds comprise, if appropriate, the adhesives, wetting agents, dispersants, emulsifiers, penetrants, preservatives, antifreeze agents, solvents, fillers, carriers, colorants, antifoams, evaporation inhibitors and pH and viscosity regulators which are customary in each case.
Components which can be used in combination with the active compounds according to the invention in mixed formulations or in the tank mix are, for example, known active compounds as they are described, for example, in Weed Research 26, 441-445 (1986), or "The Pesticide Manual", 10th edition, The British Crop Protection Council and the Royal

Soc. of Chemistry, 1994, and the literature cited therein. Examples of active compounds, which may be mentioned as herbicides, which are known from the literature
For use, the formulations, which are in commercially available form, are, if appropriate, diluted in the customary manner, for example using water in the case of wettable powders, emulsifiable concentrates, dispersions and water-dispersible granules. Preparations in the form of dusts, granules for soil application or for broadcasting and spray able solutions are conventionally not diluted any further with inert substances prior to use.
The application rate required, of the compounds according to the invention, varies with the external factors such as; inter alia, temperature, humidity and nature of the herbicide used. It can vary within wide limits, for example between 0.001 and 10.0 kg/ha or more of active substance, but it is preferably between 0.005 and 5 kg/ha.
Occasionally when dust produced by absorbing active ingredient into or mixed with a finely divided inert carrier material, for example china clay or the likes, at the time of application poses drift problem. With wettable powders and soluble powders the problems faced at the time of dilution is drift and final disposal of container as it has dust particles sticking to its sides, residues of these formulation poses great problem to environment, to operators and user.
Dusts are undesirable because of airborne contamination and handling difficulties, while liquid spray formulations involve solvent and packaging expenses, and container disposal requirements that detract from commercial desirability.
In the past, there were many methods for obtaining globular particles. For example, the raw material was placed on a rotating round plate, binder was added, and the mixture was made to rotate forming globular particles. If this method is used, the diameter of the particles was many millimeters, and sometimes much larger than that, so it was very difficult to get particles of lesser diameter. Also it was difficult to control the size of the particles. There would be a great variation in the size of the particles. This was a big problem. Also controlling the moisture was quite troublesome.
There were other methods for obtaining globular particles. For example there is the spray method. In this raw material is dissolved in a liquid, then a binder is added and it is then sprayed. Hot air is passed over this, and the liquid part of the spray is made to evaporate. Whatever is left is in the form of globular particles.
In this method, particles of size from a few microns to many hundred microns are obtained, but most of the particles are hollow. Then also, slurry adjustment is required, which makes the equipment large and cumbersome. This makes it impractical for manufacturing small quantities of larce number of products.

However, Water Dispersible Granules produced by fluidized bed spray dryer overcomes all the problem of Wettable Powders and Soluble Powders but high temperatures, high cost processing, high value capital investment as well as highly skilled staff requirements imposes a significantly prohibitive factor in widening the market acceptance.
The other known Method to overcome these problems is the extrusion method, in which the material is extruded into a tube like shape and then put into a globalizer or spherodizer to form globular particles. However it is impossible to obtain really light, small size particles in this manner, which can disperse well and easily into the water at the time of use. Thus the problem continues.
The methods known till now provides either the extruded product of larger diameter or fludised spray dry product of very fine particle size. The problems and disadvantages associated with the method of fludised bed spray drying. Similarly there are also problems and disadvantages associated with the extrusion method are impossible to obtain small particle in the range of 0.1-0.5 mm diameter. The novel improved method proposed by in this invention consists of mould soft non-standard lumps then granulate this lumps so that they form special granules with narrow size distribution
Sulfonylurea herbicides have proven to be particularly effective herbicides and are in worldwide use. The most common method of applying agricultural pesticides involves their dilution in a solvent followed by spraying of the resulting solution or dispersion. Because of the increasing costs of non-aqueous solvents and the toxicity of some of them, formulations involving water-soluble or water-dispersible granules have become increasingly popular.
Conventional methods for the preparation of water-soluble or water-dispersible granules involve fluidized bed or pan granulation techniques or the impregnation of an active pesticide agent on preformed mineral granules. In the fluidized bed or pan granulation techniques, water is added to the formulation in a granulation step which must then be removed in a drying step. The drying, accomplished by means of a stream of heated air, is expensive because it is energy intensive and requires elaborate dust collection equipment. Granules prepared by fluidized bed or pan granulation are generally sprayable upon dilution while the impregnated compositions are applied mechanically, for example, using spreaders.
Often it is desirable to use mixtures of two or more pesticides of different functions to provide broad-spectrum control over a variety of weeds, for example a mixture of a herbicides. Unfortunately, some of the individual components are physically or chemically incompatible as mixtures, especially in long-term storage. For example, sulfonylurea herbicides are known to be unstable in the presence of acidic materials as well as moisture. The chemical incompatibility can be due to an impurity present in the

complementary pesticide and not the bioactive component itself. For these reasons it would be desirable to have a sprayable, formulated product consisting of particles or granules.
SUMMARY OF THE INVENTION
A process for the preparing chemically stable non-dusty, light, spherical, water dispersible granules of herbicide suitable agricultural composition comprising the following steps:
(a) blending herbicide consisting of sulfonyl-uiea, anhydrous alkali salt, surfactant and inert filler to get a blended mixture 1,
(b) grinding the blended mixture 1 in particle sizes of 0.1 to 5 microns;
(c) post-blending the ground mixture of step (b) to get a homogeneous mass;
(d) sprinkling a liquid such as water on to the homogeneous mass of step (c) to avoid dusting and loss of the material;
(e) adding a binder as such or in solution form to the homogeneous mass of step (d) to forming a mixture 11;
(f) agitating thoroughly the mixture 11 of step (e) to form a uniform soft aggregates;
(g) granulating the aggregates of step (f) by an oscillating clit granulator to obtain
granules;
(h) separating in oversize granules and fines from the granules obtained in step(g) by sieving (0.05 to 5.0 mm);
(i) recycling the oversize granules and the fine granules of step (h) through a multimill using various size sieves, and by step (e) respectively;
(i) drying the granules of required size in Fluid Bed Dryer with or without using any inactive gas like nitrogen;
(k) sieving the granules obtained in step (j) for separation of fines and dust.

Detailed description of the invention
The present invention reside in the discovery of a simple, economic and safe method consisting preparing from of a powder mix the small, easy flowable, soft, non-standard shape lumps, then granulates this lumps so that they form granules with narrow size distribution. Further these raw semi-dried and soft granules are simultaneously conditioned by self-compressing and dried in a fluid bed drier to yield the spherical granules.
The novel granulation system involved in the process of this invention consists of
I. Moisture adjusting mixer to form uniform soft aggregates.
II. Oscillating clit granulator.
III. Multi-mill
IV. Fluid bed drier using any inactive gas like nitrogen, fuel gas, carbon dioxide air.
V. Vibro Screen for dust separation.
Pesticide (active ingredient) means herbicides, fungicides, insecticides, nematocides, miticides, virucides, algicides, bactericides, plant growth regulants, defoliants, insect attractants and repellents and particularly compatible combinations of the foregoing. A water-soluble pesticide refers to compounds, which are substantially dissolved in water under the conditions of temperature, and concentration at which application (e.g., spraying of the solution) is to be carried out. A water-dispersible form of a pesticide refers to the various agriculturally suitable formulations including wettable powders used in coatings and dry flowables used as granular substrates. Preferred are herbicides selected from the class of herbicidal sulfonylureas, nonlimitmg examples of which mclude the following. Each of these may be water-soluble or formulated in a water-dispersible or water-soluble form of one or more from metsulfuron, metsulfuron methyl, bensulfuron, chlorsulfuron, sulfometuron, triflusulfuron, pyrazosulfuron, pyrazosulfuron-ethyl, sulfosulfuron.
Some of the more recent herbicidal active compounds have veiy good application properties and can be employed at very low application rates against a wide range of grass-like and broad-leaved weeds.
However, many of the highly active compounds are not fully compatible with (i.e. not selective enough in) some important crops, such as maize, rice or cereals, thus considerably restricting their use. In some crops they can therefore not be employed at all or only at application rates so low that the desired broad herbicidal activity against harmful plants is not ensured. Specifically, the herbicide of the formula (Al) defined

urther below and salts thereof cannot be employed entirely selectively against harmful )lants in maize, rice, cereals or some other crops.
rhe process of the invention is more advantageous when the herbicide is metsulfuron, netsulfuron methyl, benzsulfuron, chlorsulfuron, sulfometuron, triflusulfuron, )yrazosulfuron, pyrazosulfuron-ethyl, sulfosulfuron can be any one or in combination of wo or more of these. Most preferably, the process of the invention is as described earlier. However, the process of the invention can also be carried out with herbicide(s) hat has been previously micronised because even when using micronised herbicide the resulting composition using some prior art methods would require milling which helps to micronise the other ingredients except technical and helps to distribute the ather ingredients uniformly in the final mixture which is processed as per the process of this invention. The process of the invention is carried out with the presence of Sulfonylurea and other herbicides and stabilizer, but it also can be carried out with one or more Sulfonylurea and other herbicides and with or without a stabilizer.
Anhydrous base salts in the compositions may convert free water to crystalline waters of hydration. A preferred anhydrous base salt is that in which the base salt is an anhydrous sodium, ammonium salt, calcium, potassium, lithium salts and polyvalent cat-ions.
In addition, a preferred stabilizer is sodium metasilicate and metal carbonate.
A preferred binder is one selected from the class consisting of pyrrolidone derivative, ethylene oxide/propylene oxide copolymer, polyethoxylated dinonyl phenol, polyethylene glycol, and mixtures thereof.
The preferred sulfonylurea herbicides are Metsulfuron-methyl, metsulfuron, chlorsulfuron, pyrazosulfuron, pyrazosulfuron methyl, sulfosulfuron.
The process of the invention produces chemically stable non-dusty, light, spherical, water dispersible granules of herbicides. The resulting granules can also be described as non-dusty, light, spherical granules of the size 0.1 to 1.5 mm, water dispersible and or water soluble granules of herbicides.
The preferred size of the active herbicidal particle is 1- 50 microns, especially for herbicides with low water solubility, to promote water dispersion, avoid premature settling and avoid nozzle and screen pluggage during tank-mixing or application in the field. Water-soluble herbicidal particles may be of larger size.
The granules can be comprised of the mixture of herbicidal particles which are chemically incompatible in a conventional granule made by water spraying, such ad fluid bed spray drier of pan granulation because the herbicidal particles can be made compatible by adding the stabilizers and anti-caking agents.

The composition of this invention can be prepared by several process (either in batch of continuous mode) including the process wherein:
a) all the ingredients are mixed and liquid with or without binder is sprayed until the granules have grown to the desired size, following which the liquid addition is stopped
b) and the material and granules are sieved through the desired sieve to separate the oversize, desired, and the fines ; the oversize is then processed through multimill to have a smaller size and recycled separately or along with the fines for granulation with the addition of the homogenous mixture of all ingredients until the desired size is obtained; the desired size is then conditioned and dried to have the required liquid content level;
c) all the ingredients are intensely mixed and liquid added such that the spraying of binder solution effect granulation, following which the aggregates were taken for further processing which finally avoids dusting and loss of the material during further processing;
d) all the ingredients are intensely mixed along with the binder and liquid added to
effect granulation, following which the aggregates were taken for further
processing which finally avoids dusting and loss of the material during further
processing but yields in a soft, breakable and dust containing product;
As described above the method
a) involve gentle mixing of the active herbicide which is pre-ground/ micronised, can be carried out in a blender (e.g. Paddle or ribbon type blenders, vee- blenders, zig-zag blenders, lodgie blenders, nauta mixer, ball mill,booth mixer);
b) involves intensely sheared which can be carried out in a micronizer (e.g. Air jet mill, air classifying mill, turbomill, ultrafine mill, pin mill and others) and mixing in blenders , during mixing the binder solution may or may not be sprayed;
c) involves intensely sheared which can be carried out in a micronizer (e.g. Air jet mill, air classifying mill, turbomill, ultrafine mill, pin mill and others) and mixing in blenders , during mixing the liquid may or may not be sprayed;
The processes of the prior art have the disadvantage of requiring a drying step at some stage of production of the formulations disclosed and because the final products contain environmentally-sensitive chemicals such as sulfonylureas and other potentially volatile components, large and expensive air-purification systems are necessary in drying operations to prevent untoward chemical release.

In the prior art, the granulation requires pan granulator; spray drying equipment, fluid bed spray drying granulator, extruders and large, expensive air -purification systems.
Prior to this invention, no granules in the range of 0.1 to 1.5mm was possible with a very less variation in the sizes of the particles and no easy method to manufacture any standardized size material with high yield of uniform material of this invention which is a chemically stable, non-dusty, light, spherical, and water dispersible granules
Now according to the present invention there is no need of such equipments and air purification system to clean large volumes of air in drying operation at manufacturing facilities. In present invention drying operation may be carried out with or without using any inactive gas like nitrogen, fuel gas, carbon dioxide, air etc.
The present invention relates to a novel process for preparing chemically stable, non-dusty, spherical, light, water dispersible granules of Herbicides. The herbicides in the novel process of this invention do not decompose in the storage conditions of 0 to 60 ° C. The process of the instant invention is advantageous over known processes that require rotating round plate, spray method, Fluid bed spray dryer, extrusion method because fine particles or dust of environmentally-sensitive herbicides and other potentially volatile components may be released to the environment in the processing step. Known process conditions include large, expensive air-purification systems, which are required, to clean the large volumes of forced air required in drying operations at manufacturing facilities. The present invention precludes the need of such equipment.
Advantage of the present granules includes potential incorporation of the herbicide in the same granules and at low cost. The process used to prepare these granules is simple and does not require specialized technology. It utilizes readily available selected equipment.
One skilled in the art can select dyes, humectants, spreading agents, corrosion inhibitors, fillers, stickers, odorants, bitterants or other formulation ingredients to obtain some special properties and still be within the scope of this invention.
A drying step in a typical formulation process requires longer heating times, higher temperatures, and a forced air system to remove the water vapor and other volatiles. As indicated above, the forced air must be purified to prevent contamination of the environment, and these purification systems are large and expensive. No such purification systems are required in the process of the present invention.
As mentioned above, in any of the methods in use it was not possible to obtain particles in the range of 0.1mm to 1.5mm. Also, there was a large variation in the sizes of the

particles, and it was relatively difficult to manufacture any standardized size. If uniform material was extracted, the yield was very low.
According to this invention, it is possible to obtain non-dusty, light, spherical granules pf the size 0.1 to 1.5mm, which was not possible in the past. It also minimises the variation in the size of the particles.
Various salts are known to effect herbicidal activity and are routinely added to enhance weed control. Another advantage of the present invention is that the base salts as described are known to enhance biological efficacy are already present and therefore need not be tank-mixed at the time of application.
Another advantage is that the binder selected and present in the compositions of the present invention enhances the activity of the herbicides.
Surfactants additionally may or may not be tank-mixed with herbicides to obtain a comparable improvement in efficacy.
The nature of the herbicides used is available in the form of crystalline material which is already milled to a sub micron size or not milled to have a finer particles in comparison to technical material itself, incorporated into the composition along with anhydrous base salt, ant caking agent, anti-foaming agents, stabilizer, surfactant, binder to have a composition of the invention which is a
1) dry, free-flowing and micronizable to a fine powder,
2) inert to decomposition of a herbicide in the composition, and
3) available for direct processing to finished granules by following the process of this invention.
When the herbicide is used then the weight percent of the stabilizer is 0.01 - 30 % and depends upon the type of the active compounds in use. Useful anhydrous base salts are those, which have hydrated forms with melting points above 60 ° C. Useful anhydrous base salts have cations that include sodium, ammonium, calcium, potassium, lithium, and polyvalent cations as that part of the salt with carbonate, carbonate/phosphate blends, citrate, metaborate, metasilicate, pyrophosphate, sulfate and tetraborate, as well as others.
Potassium salts are less desirable because of the problem of forming hygroscopic compositions. Lithium salts are useful but can be more expensive than the corresponding sodium salt. Polyvalent cationic salts are useful but can deactivate many herbicides. Therefore, sodium based salts are preferred.
Useful examples of anti-caking and anti-foaming agents are magnesium sterate, sodium stearate and silicon oil derivaitves well known to those in the art.

Suitable stabilizers comprise metal carbonate salts, metal acetate salts, or metal metasilicate salts which protect the sulfonylurea from decomposition in the formulation. The metal salts comprise divalent and monovalent metals. Sodium carbonate or sodium metasilicate are preferred.
Any surface active material comprised of one or more components which dissolve rapidly in water, have sufficient viscosity near the melting point for tackiness, and are thus capable of acting as a binder can be used . A preferred amount of binder used in this invention is 0.1-40 % by weight based on the total weight of the composition. Suitable binders include any component or mixture of components meeting the following criteria.
(1) have a melting point range within 40 degrees to 120 degrees C;
(2) have a hydrophile/lipophile balance (HLB) of about 14 or greater;
(3) dissolve in mildly-agitated water in 30 min. or less, preferably 15 min. or less;
(4) have a melt viscosity of at least 200 centipoises (cps);
The process of the invention mentioned above may become more apparent by the examples set forth herein below. These examples are provided merely as illustrations of the invention and are not intended to be construed as a limitation thereof.
Example-1
To prepare Metsulfuron Methyl 20% (by mass) granules:

Composition ingredients
Metsulfuronmethyl Technical (purity 95%) Stabilizer (Sodium Carbonate) Wetting Agent (Supragil WP) Dispersing Agent (Geropon SC-213) Binder (Polyvinylpyrrolidone K-30) Defoamer (Rhodorsil 426-R) Filler (Soluble Starch) (Kaolin)

Total

Quantity (% w/w) in mn.
21.05
3.00
3.00
8.00
1.00
0.30
50.00
13.65
100.00

Process for preparation of above composition comprises blending Metsulfuronmethyl Technical (purity 95%), fillers, stabilizer, anhydrous salt and surfactant. Then grinding the said blendmg mixture and post blending it to get a homogeneous mass and then sprinkling water on it to avoid dusting of the powder then adding the binder in to it and

agitating thoroughly to get uniform soft aggregates. Thereafter granulating the said aggregates by an oscillating clit granulator to get granules thereafter separating oversize and fines and then drying the granules in 0.1- 1.5mm size and thereafter sieving to obtain the granules. The attrition value is 28%. This composition is non-caking and disperses in water within 120 seconds to give a sprayable mixture. The decomposition of Metsulfuron methyl at 54°C for 7 days is 4.0% by mass.
Example-2
Preparation of Metsulfuron methyl 20% (by mass) granules to study the properties of
granules prepared:

Process for preparation of above composition comprises blending Metsulfuronmethyl Technical (purity 95%), fillers, stabilizer, anhydrous salt and surfactant. Then grinding the said blending mixture and post blending it to get a homogeneous mass and then sprinkling water on it to avoid dusting of the powder then adding the binder in to it and agitating thoroughly to get uniform soft aggregates. Thereafter granulating the said aggregates by an oscillating clit granulator to get granules thereafter separating oversize and fines and then drying the granules in 0.1-1.5mm size and thereafter sieving to obtain the granules.The resultant product dispersed in water within 120 seconds to give a sprayable mixture containing dispersed Metsulfuron ethyl active content. All the composition prepared in example-2 is in non-caking form. The attrition values are 2(a) 26%; 2(b) 30%; 2(c) 23%; 2(d) 20%; 2(e) 25%. The product studied for decomposition of Metsulfuron methyl content at 54°C for 7 day and found to be 4.6, 3.5, 3.8, and 4.1% by mass respectively.
Example-3
To prepare Sulfosulfuron 75% (by mass) granules:
Composition

Ingredients
Sulfosulfuron Technical (purity 93.75%) Stabilizer (Sodium Carbonate) Wetting Agent (Supragil WP) Dispersing Agent (Geropon SC-213) Binder (Lactose) Defoamer (Tallow Soap) Filler (Soluble Starch) (Kaolin)

Total

Quantity (% w/w) in gm. 80.00 2.00 2.00 8.00 0.80 0.10 5.00 2.10 100.00

Process for preparation of above composition comprises blending Sulfosulfuron Technical (purity 93.75%), fillers, stabilizer, anhydrous salt and surfactant. Then grinding the said blending mixture and post blending it to get a homogeneous mass and then sprinkling water on it to avoid dusting of the powder then adding the binder in to it and agitating thoroughly to get uniform soft aggregates. Thereafter granulating the said aggregates by an oscillating clit granulator to get granules thereafter separating oversize and fines and then drying the granules in 0.1-1.5mm size and thereafter sieving to obtain the granules.The granules obtained have an attrition value of 12%. The granules are non-caking and disperse within 120 seconds to give a sprayable mixture. The composition of sulfosulfuron at 54°C for 7 days is 1.2% by mass.

Example-4

Preparation of Sulfosulfuron 75% (by mass) granules to study the properties of granules prepared:
Sulfosulfuron Technical (purity 93.75%) Stabilizer
5.00 5.00 5.00 5.00
5.00
Wetting Agent (Supragil WP) Dispersing Agent (Geropon SC-213) Binder (Lactose) Defoamer (Tallow Amine) Fillers (Soluble Starch)

2.10
(Kaolin)
Total
Where 1= Sodium Carbonate 11= Sodium Acetate 111= Tri Sodium Phosphate

2.10 2.10 2.10 2.10
100.00 100.00 100.00 100.00 100.00

Process for preparation of above composition comprises blending Sulfosufuron Technical (purity 93.75%), fillers, stabilizer, anhydrous salt and surfactant. Then grinding the said blending mixture and post blending it to get a homogeneous mass and then sprinkling water on it to avoid dusting of the powder then adding the binder in to it and agitating thoroughly to get uniform soft aggregates. Thereafter granulating the said aggregates by an oscillating clit granulator to get granules thereafter separating oversize and fines and then drying the granules in 0.1-1.5mm size and thereafter sieving to obtain the granules.The resultant product dispersed in water within 120 seconds to give a sprayable mixture containing dispersed sulfosulfuron active content. The whole composition as prepared in example-4 is non caking. The attrition values are 4A 13%; 4B 12.5% 4C 11.0%; AD 10%; and AE 15.0%. The product studied for decomposition of Sulfosulfuron content at 54°C for 7 days and found to be 1.4; 1.1; 1.00; 0.78; and 0.90% by mass respectively.
Example-5
To prepare Metsulfuron Methyl 0.5% (by mass) granules:
Composition
Ingredients Quantity (% w/w) in am.
Metsulfuronrnethyl Technical (purity 95%) 0.564
Filler (Soluble Starch) 50.00
(Kaolin) 49.436
Total 100.000
Process for preparation of above composition comprises blending Metsulfuronrnethyl Technical (purity 95%), fillers. Then grinding the said blending mixture and post blending it to get a homogeneous mass and then sprinkling water on it to avoid dusting of the powder then adding the binder in to it and agitating thoroughly to get uniform soft aggregates. Thereafter granulating the said aggregates by an oscillating clit granulator to get granules thereafter separating oversize and fines and then drying the granules in 0.1-1.5mm size and thereafter sieving to obtain the granules.This powder has been used for preparation of 0.5% granules, which is a product to control weeds in wheat. The prepared granules give a good dispersion of active ingredient in direct application and even with water, but pose a problem of sedimentation in the spray tank.
Example-6
To prepare Metsulfuron Methyl 20% (by mass) granules:

Composition Ingredients
Metsulfuron methyl Technical (purity 95%) Stabilizer (Sodium Carbonate) Wetting Agent (Supragil WP) Zeolite

Quantity (% w/w) in tan.
5.64
1.00
5.00
15.00

Sodium Acetate Sodium Lauryl Sulphate Defoamer (Rhodorsil 426-R) Filler (Soluble Starch) (Kaolin)

Total

3.00
5.00
1.50
50.00
13.86
100.00

Process for preparation of above composition comprises blending Metsulfuronmethyl Technical (purity 95%), fillers, stabilizer, anhydrous salt and surfactant. Then grinding the said blending mixture and post blending it to get a homogeneous mass and then sprinkling water on it to avoid dusting of the powder then adding the binder in to it and agitating thoroughly to get uniform soft aggregates. Thereafter granulating the said aggregates by an oscillating clit granulator to get granules thereafter separating oversize and fines and then drying the granules in 0.1-1.5mm size and thereafter sieving to obtain the granules. The resultant product dispersed in water in less than 120 seconds and a sprayable mixture is obtained.
Example-7
To prepare Metsulfuron Methyl 20% (by mass) granules:


Composition ingredients
Metsulfuronmethyl Technical (purity 95%)
Sodium Pyrophosphate
Zeolite
Tri Sodium Phosphate
Surfactant Mixture
Defoamer (Silicon Oil Derivative)
Lactose
Ammonium Carbonate

Total

Process for preparation of above composition comprises blending Metsulfuronmethyl Technical (purity 95%), fillers, stabilizer, anhydrous salt and surfactant. Then grinding the said blending mixture and post blending it to get a homogeneous mass and then sprinkling water on it to avoid dusting of the powder then adding the binder in to it and agitating thoroughly to get uniform soft aggregates. Thereafter granulating the said aggregates by an oscillating clit granulator to get granules thereafter separating oversize and fines and then drying the granules in 0.1-1.5mm size and thereafter sieving to obtain the granules.The resultant granules are water dispersible and contain 20% of active content and have an attrition value of 15%.

£xample-8
To prepare Metsulfuron Methyl 30% (by mass) granules:
Composition
Ingredients Quantity (% w/w) in gm.
iVletsulfuronmethyl Technical 31.58
Sodium Acetate 2.00
PPT Silica 0.50
Tri Sodium Phosphate 7.00
Tallow Soap 2.00
Morwet D-425 20.00
Starch 20.00
Ammonium Carbonate 16.92
Total 100.00
Process for preparation of above composition composes blending Metsulfuronmethyl Technical, fillers, stabilizer, anhydrous salt and surfactant. Then grinding the said blending mixture and post blending it to get a homogeneous mass and then sprinkling water on it to avoid dusting of the powder then adding the binder in to it and agitating thoroughly to get uniform soft aggregates. Thereafter granulating the said aggregates by an oscillating clit granulator to get granules thereafter separating oversize and fines and then drying the granules in 0.1-1.5mm size and thereafter sieving to obtain the granules. This powder has been used for preparation of 30% granules which give a fine dispersion of active content in slightly agitated water i.e. approximately 50 seconds after dilution.


£xample-9
To prepare Metsulfuron Methyl 50% (by mass) granules:
Composition ingredients
Metsulfuronmethyl Technical Sodium Acetate Tri Sodium Phosphate Surfactant Mixture Defoamer (Rhodorsil 426-R) Potato Starch Ammonium Sulphate
Total

Process for preparation of above composition comprises blending Metsulfuronmethyl Technical, fillers, stabilizer, anhydrous salt and surfactant. Then grinding the said blending mixture and post blending it to get a homogeneous mass and then sprinkling water on it to avoid dusting of the powder then adding the binder in to it and agitating thoroughly to get uniform soft aggregates. Thereafter granulating the said aggregates by an oscillating clit granulator to get granules thereafter separating oversize and fines and then drying the granules in 0.1-1.5mm size and thereafter sieving to obtain the granules. The resultant granules contain 50% of active ingredient. Upon dilution with water, the product totally dissolves in about 50 seconds and gives a clear transparent pale yellow to light brown coloured solution of the active content.
Example-10
To prepare Sulfosulfuron granules:

Composition Ingredients
Herbicide Sulfosulfuron Filler (Kaolin)

Total

Quantity (% w/w) in gm. 0.534 99.466 100.000

Process for preparation of above composition comprises blending Herbicide Sulfosulfuron and fillers. Then grinding the said blending mixture and post blending it to get a homogeneous mass and then sprinkling water on it to avoid dusting of the powder then adding the binder in to it and agitating thoroughly to get uniform soft aggregates. Thereafter granulating the said aggregates by an oscillating clit granulator to get granules thereafter separating oversize and fines and then drying the granules in 0.1-1.5mm size and thereafter sieving to obtain the granules.The resultant product is hard and heavy in its state and does not disperse in water in 180 seconds also.
Example-11
To prepare Sulfosulfuron 25% (by mass) granules:


Ammonium Carbonate Kaolin

Total

10.00 14.33
100.00

Process for preparation of above composition comprises blending Sulosulfuron Technical, fillers, stabilizer, anhydrous salt and surfactant. Then grinding the said blending mixture and post blending it to get a homogeneous mass and then sprinkling water on it to avoid dusting of the powder then adding the binder in to it and agitating thoroughly to get uniform soft aggregates. Thereafter granulating the said aggregates by an oscillating clit granulator to get granules thereafter separating oversize and fines and then drying the granules in 0.1-1.5mm size and thereafter sieving to obtain the granules. The powder is used to prepare 25% granules. This gives an attrition value of 18%.
Example-12
To prepare Sulfosulfuron 75% (by mass) granules:

Composition Ingredients
Sulfosulfuron Technical (purity 93.75%)
Tri Sodium Phosphate
Rhodosil 426-R
Supragil WP
GeroponSC-213
Lactose
Starch
Ammonium Sulphate

Total

Quantity (% w/w) in am. 80.00 3.00 0.30 4.00 8.00 2.00 1.00 1.70 100.00

Process for preparation of above composition comprises blending Sulfosulfuron Technical (purity 93.75%), fillers, stabilizer, anhydrous salt and surfactant. Then grinding the said blending mixture and post blending it to get a homogeneous mass and then sprinkling water on it to avoid dusting of the powder then adding the binder in to it and agitating thoroughly to get uniform soft aggregates. Thereafter granulating the said aggregates by an oscillating clit granulator to get granules thereafter separating oversize and fines and then drying the granules in 0.1-1.5mm size and thereafter sieving to obtain the granules.
The product is processed for the preparation of 75% Sulfosulfuron granules, used to control weeds in wheat. The granules prepared give a fine dispersion of the active ingredient in slightly agitated water approximately in 80 seconds after dilution and these granules in 13.5 gm. Quantity along with 500 ml of liquid surfactant in water give a transparent pale yellow to light brown coloured solution.
Example-13

To prepare Sulfosulfuron 85% (by mass) granules:


Composition Ingredients
Sulfosulfuron Technical Tri Sodium Phosphate Silicon Defoamer Sodium Carbonate Lactose Starch
Ammonium Sulphate
Total

Process for preparation of above composition comprises blending Sulfosulfuron Technical, fillers, stabilizer, anhydrous salt and surfactant. Then grinding the said blending mixture and post blending it to get a homogeneous mass and then sprinkling water on it to avoid dusting of the powder then adding the binder in to it and agitating thoroughly to get uniform soft aggregates. Thereafter granulating the said aggregates by an oscillating clit granulator to get granules thereafter separating oversize and fines and then drying the granules in 0.1-1.5mm size and thereafter sieving to obtain the granules. The resultant product disperses in water in 120 seconds and gives a sprayable mixture containing dispersed 85% sulphosulfuron active content. This has an attrition value of 27% and decomposition of active is 2.8% after 7 days at 54°C .
Example-14
To prepare Sulfosulfuron 90% (by mass) granules:
Composition
Ingredients Quantity (% w/w) in gm.
Herbicide Sulfosulfuron 96.00
Tri Sodium Phosphate 0.50
Polyvinylpyrrolidone K-30 1.00
Ammonium Sulphate 2.50
Total 100.00
The Process for preparation of above composition comprises blending Herbicide Sulfosulfuron, fillers, stabilizer, anhydrous salt and surfactant. Then grinding the said blending mixture and post blending it to get a homogeneous mass and then sprinkling water on it to avoid dusting of the powder then adding the binder in to it and agitating

thoroughly to get uniform soft aggregates. Thereafter granulating the said aggregates by an oscillating clit granulator to get granules thereafter separating oversize and fines and then drying the granules in 0.1 -1.5mm size and thereafter sieving to obtain the granules. Resultant granules contain 90% active ingredient. The granules show a decomposition of 2.5% in 7 days at 54°C. The attrition value is 20% and disperses in less than 90 seconds but is soft.
TESTS:
Non-caking was measured by the C1PAC test, which is described in MT 172 "Flowability of Water Dispersible Granules after Heat Test Under Pressure". The Attrition test measures the stability of the granules to break down under dry conditions. The granules of the present invention exhibit low attrition as determined by the Attrition test.
A sample of the granules to be tested are separated into size fractions first by sieving of granules passing a 12 mesh screen so the largest aggregate in any fraction has a diameter no more than 1.4 times larger than the smallest granule in the fraction. For example, in the fraction isolated between 12 and 60 mesh sieves, the largest aggregate has a diameter of approximately 2 mm and the smallest aggregate has a diameter slightly larger than 74 microns. Other suitable sieve fractions can be isolated, for example, between 25 and 35 mesh sieves, 30 and 40 mesh sieves, 100 and 140 mesh sieves, etc. A three-gram sample from the isolated size fraction is placed in jar. One hundred and twenty 0.64 cm diameter and fourteen 1.3 cm diameter steel balls are added to the jar, the jar is capped and is then placed in a rotating device such as ajar roller and rotated around its longitudinal axis at 25-26 RPM for exactly two minutes. The jar is removed from the roller, its contents discharged carefully to prevent further grinding of the remaining aggregates onto a nest sieves, consisting of a No. 12 sieve to remove the balls and a sieve in which the sieve opening is equal to the diameter of the smallest aggregates in the original sample, and a pan. The stacked sieves are gently rotated to separate the steel balls from the sample. The No. 12 sieve is then removed and the screening of the sample on the other sieve continued with rotation and tapping, until all the fines are collected in the pan. The fine material in the pan is weighed, and the weight percent of mechanical breakdown of the aggregates is calculated: Attrition values of less than 40%, and preferably less than 30%, are acceptable.
The Break-up test measures the time it takes for the granules to form dispersion in water or dissolve in water. A 0.5 sample of granules is added to a 100 ml graduated cylinder containing 90 ml of distilled water at 25°C and the cylinder clamped in the center, stoppered and rotated about the center at 8 RPM until the sample is completely broken up in the water. The time for break up is measured. The granules of the invention should break up in less than 5 minutes, preferably less than 2 minutes.

The present invention further pertains to a method for controlling the growth of undesired vegetation which comprises applying to the locus to be protected, by aqueous spraying, an effective amount of the composition described above. The method of the present invention comprises adding an effective amount of the herbicidal composition to an aqueous medium, forming a solution/suspension of the composition, and applying the solution in an effective amount to the plant/locus to be protected, by spraying. The dispersed particles formed on dilution should be no greater than 45 microns, and preferably less than 15 microns, in their largest dimension to avoid nozzle pluggage or premature settling which results in uneven application of the herbicide. Consequently, it is preferred that all of the components of the formulated product rapidly and completely dissolve in the dilution water prior to aqueous spraying. For this purpose extra quantity of the surfactant in solid or liquid form can also be used. The term "aqueous-sprayable" as employed in this disclosure refers to this ability of the composition to dissolve or disperse in an aqueous solvent and be subsequently sprayed.

We claim:
A process for the preparing chemically stable non-dusty, light, spherical, water dispersible granules of herbicide suitable agricultural composition comprising the following steps:
(a) blending herbicide consisting of sulfonyl-urea, anhydrous alkali salt, surfactant and inert filler to get a blended mixture 1,
(b) grinding the blended mixture 1 in particle sizes of 0.1 to 5 microns;
(c) post-blending the ground mixture of step (b) to get a homogeneous mass;
(d) sprinkling a liquid such as water on to the homogeneous mass of step (c) to avoid dusting and loss of the material;
(e) adding a binder as such or in solution form to the homogeneous mass of step (d) to forming a mixture 11;
(f) agitating thoroughly the mixture 11 of step (e) to form a uniform soft aggregates;
(g) granulating the aggregates of step (f) by an oscillating clit granulator to obtain
granules;
(h) separating in oversize granules and fines from the granules obtained in step(g) by sieving (0.05 to 5.0 mm);
(i) recycling the oversize granules and the fine granules of step (h) through a multimill using various size sieves, and by step (e) respectively;
(j) drying the granules of required size in Fluid Bed Dryer with or without using any inactive gas like nitrogen;
(k) sieving the granules obtained in step (j) for separation of fines and dust.
2. The process of claim 1 wherein active concentration by weight of the composition of, the said herbicide is in the range of 0.5%-95.0%, the anhydrous alkali salt is in the range of 0.1%-10.0%, the surfactant is in the range of 0. l%-25% and the inter filler is in the range5.0%-99.5%.

3. The process of claim 1 wherein herbicides are selected from metsulfuron, metsulfuron
methyl, benzsulfuron, chlorsulfuron, sulfometuron, triflusulfuron, pyrazosulfuron, pyrazo-sulfuron-ethyl, sulfosulfuron.
4. The process as claimed in claim 1 wherein the binder is in range of 0.1-40% of the
liquid.
5. The process as claimed in claim 1 wherein the anhydrous alkali salt is selected from sodium and/or ammonium salts.
6. The process as claimed in claims lto 4, wherein the surfactant such as non-ionic, or cationic is used.
7. The process as claimed in claim 1 wherein the process includes blending of anti-caking agent such as Sodium stearate or Magnesium Stearate and antifoaming agents such as silicon oil derivative.
8. A composition prepared by the process as claimed in any of the above mentioned claims is a chemically stable, water dispersible granules of herbicidal composition comprising 0.5-.95% by weight of the composition a herbicide, 0.1-10.0% by weight of the composition an anhydrous base salt, 0.1-25% by weight of the composition a surfactant and 5.0-99.50% by weight of the composition inert fillers.
9. The composition as claimed in claim 7 wherein the herbicide is selected from metsulfuron, metsulfuron methyl, benzsulfuron, chlorsulfuron, sulfometuron, triflusulfuron, pyrazosulfuron, pyrazo-sulfuron-ethyl, sulfosulfuron.
10. A process for preparing chemically stable non-dusty, light, spherical, water dispersible granules of herbicide suitable agricultural composition, substantially as herein described with reference to the text and examples 1 to 14.
Dated this 31st Day of Oct. 2002
(M. B. TR1VED1)
COMPANY SECRETARY
UNITED PHOSPHORUS LTD.