FORM 2
THE PATENTS ACT, 1970
(39 OF 1970)
COMPLETE SPECIFICATION
{See Section 10)
A CHEMICALLY STABLE, SYNERGISTIC HERBICIDAL COMPOSITION.
We, UNITED PHOSPHORUS LIMITED, a company incorporated under the Companies Act, 1956 and having its registered office at 3-11, GIDC, Vapi - 396 195, Gujarat, India, and having its office at Uniphos House, 11th Road, CD. Marg, Khar (West), Mumbai - 400 052, 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:

- 9 MAR 2004

Field of Invention:
The present invention relates to a chemically stable, synergistic herbicidal composition. More specifically, it relates to a chemically stable synergistic herbicidal composition containing Metsulfuron Methyl and Sulfosulfuron and a process for preparing the same.
Background and Prior Art:
Weeds grow in the fields where they compete with the crops for water, soil nutrients, light and space and thus reduce crop yields. They also harbour insects, pests and microorganisms. Certain weeds release into the soil inhibitors or poisonous substances, which are harmful to the plants, human beings and livestock. They increase the expenditure on labour and equipment, render harvesting difficult, and reduce the quality and marketability of the agricultural produce.
Weeds seeds germinate earlier, their seedlings grow faster, they flower earlier, and form seeds in profusion, and mature ahead of the crop they infest. Weeds have a remarkable capacity to germinate under varied conditions but very characteristically they are season bound and the peak period of the germination always takes place in certain season in the regular succession year after year.
Chemical weed control is easier, less time consuming and less costly than weeding by hired labourers. Most of the presently available herbicides provide only a narrow-spectrum of weed control. These herbicides control either grasses or broad leaf weeds but not both. Many of them have activity only on annual species while a few are only effective against perennials. For example, in certain crops particularly in wheat specific herbicides are used to control grassy weeds. Similarly, to control the broad leaf weeds like Chenopodium album, Melilotus alba, Anagallis arvensis and Rumex, different specific herbicides have to be used separately. Thus there is a danger of species replacement and hitherto less dominant weed becoming prominent and devastating.
With the continuous use of herbicides in monoculture systems, herbicide resistance development is becoming problematic. Herbicide resistance is the inherited ability not to be controlled by herbicide. The indiscriminate use of agricultural chemicals led to two different problems due to persistence - one being harmful/inhibitive effect on sensitive crop growth in succession in a cropping system and thus reducing choice of crops. The second is the toxic chemical residues left underrated, which may result in potential ecological hazard and pollution. In addition there are problems of secondary pests and resurgence of weeds. As a result, change in weed communities are observed.
In many cases, active herbicides in combination have shown multifacet advantage than when applied individually. Since the combination demonstrates a potency or/and activity level, exceeding that which might be expected from a mere addition of the individual potencies of the components is thereby called as "synergism." The present invention highlights the synergistic effect of a novel composition prepared using the two selected herbicides that exhibits the total enhanced effect of higher level of activity and a broader spectrum of weed control rather than a narrow spectrum of weed control while these two herbicides are used individually.

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 adverse effects of certain sulfonylureas on the follow-crop and persistence in the soil for long time periods, it is advisable to use very low concentrations of these herbicides.
Some of the known methods to overcome these problems is (1) to use other adjuvants in the mixing tank such as Herbicide safeners or inerts, (2) use of buffering agents and (3) use of specific application techniques and specially designed applicators.
WO 91/13546 discloses the preparation of dry flowable agricultural compositions comprising an active ingredient, water-soluble heat activated binder and a chemical stabilizer. Among the active ingredients disclosed are only sulfonylureas in combination with glyphosate with a disclosure that one or more may be used. But the process does not describe a combination of two sulfonylureas.
US Patent No. 5569639 discloses a process for the preparation of dry flowable agricultural compositions comprising glyphosate or glyphosate salt and sulfonylurea herbicide. This process also produces a freeflowing granular composition of glyphosate and sulfonylurea but not of two sulfonylureas.
A premix by the trade name of FINESSE is known to be a combination of Chlorsulfuron and Metsulfuron.
However, Metsulfuron methyl in combination with Sulfosulfuron is not yet known in the art. Sulfosulfuron has comparatively negligible adverse effects than Metsulfuron methyl. 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 herbicides. These can also be used as tank mixes. Unfortunately, some of the individual components are physically or chemically incompatible as mixtures. Also, the active ingredients have to be mixed as and when required at the place of application and do not result in a compatible and storage stable formulation product, prepared in the manufacturing plant and made available to use in a packed container, on the shelf. The specific concentration or concentration range of the compound that exhibits synergistic effect is not disclosed. If the ingredients are mixed in advance, i.e. an admixture, and kept, their activity may be either reduced or totally lost. So using such mixtures as spray solutions may sometimes work antagonistically rather than synergistically. Thus, there is a need to develop a herbicidal composition to increase the agricultural yield, having high synergistic action, no cross-resistance, avoids excess loading of the toxicant to the environment and has negligible impact on environmental safety. It also necessitates the need for a synergistic herbicidal composition, which is a physico-chemically compatible formulation available in the form of storage stable, safely packed, ready to use formulation. The present invention achieves the above objective by providing a synergistic composition with many advantages.
Therefore the main objective of the present invention is to provide a chemically stable synergistic herbicidal composition and a process for preparing the same.
Another objective of the present invention is to provide a chemically stable synergistic herbicidal composition which is storage stable.

Still another objective of the present invention is to provide a chemically stable synergistic herbicidal composition, which is effective in controlling both grasses as well as broad leaf varieties of weeds.
Yet another objective of the present invention is to provide a chemically stable synergistic herbicidal composition, which demonstrates a high, controlling effect with reduced crop protection cost, increased crop yield and reduced environmental load.
Still another objective of the present invention is to provide a chemically stable synergistic herbicidal composition, which has a broader spectrum of activity and reduces the risk of developing resistance.
Another objective of the present invention is to provide a process for the preparation of chemically stable synergistic herbicidal composition which is storage stable.
Still another objective of the present invention is to provide a process for the preparation of chemically stable synergistic herbicidal composition, which is effective in controlling both grasses as well as broad leaf varieties of weeds.
Yet another objective of the present invention is to provide a process for the preparation of chemically stable synergistic herbicidal composition, which demonstrates a high, controlling effect with reduced crop protection cost, increased crop yield and reduced environmental load.
Still another objective of the present invention is to provide a process for the preparation of chemically stable synergistic herbicidal composition, which has a broader spectrum of activity and reduces the risk of developing resistance.
Summary of the Invention:
Accordingly, the present invention provides a chemically stable synergistic herbicidal composition comprising Metsulfuron Methyl, active content, 5 to 10% by weight of composition, and, Sulfosulfuron, active content, 70 to 80% by weight of composition, with 1 to 20% w/w of inert fillers, 1.0 to 10% w/w of Polyoxyethylene Sorbitan Fatty Acid Ester along with 0.1 to 10% w/w of a stabilizer, 0.1 to 1% w/w of a defoamer and 0 to 10% w/w of wetting and dispersing agents.
The inert filler is selected from precipitated silica, kaoline, bentonite, dolomite, Attapulgite and the like or a mixture of these, preferably a mixture of Attapulgite (30-40%) and precipitated silica (60-70%).
The stabilizer may be ammonium sulphate or hexamethylene tetramine, preferably hexamethylene tetramine.
The Defoamer may be selected from silicone defoamers, preferably Rhodorsil 426R.
The wetting agent may be selected from sodium dialkyl naphthalene sulphonates, alkyl ethoxylates, ether sulphates or other agents known in the art.

The dispersing agent may be selected from sodium naphthalene sulphonate, sodium lignosulphonate, polycarboxylates or other agents known in the art.
The chemically stable synergistic herbicidal composition may be prepared as follows:
a) Preparing a Mixture-A in the following steps:
(i) Pre blending 5-10% Metsulfuron Methyl active content, 20-40% of
Sulfosulfuron active content and 0.1-10% of inert filler; (ii) Milling the pre blend, (iii) Post blending the milled mixture to get the Mixture-A;
b) Preparing a Mixture-B in the following steps:
(i) Pre blending 30-60% of sulfosulfuron active content, 0.1-10% Stabilizer, 0.01-
10% of inert filler, with 0-5% wetting and 0-l%dispersing agent; (ii) Milling the pre blend; (iii) Post blending the milled mixture to get the Mixture-B;
c) Making 10-40% w/w of the composition, a Spray Solution by mixing 10-100 parts Polyoxyethylene Sorbitan Fatty Acid Ester along with 1-10 parts defoamer and 50-500 parts water;
d) Charging completely the Mixture-A in a Roto Granulator, having a rotor and a pan, followed by mixing it with the help of the rotor for 4-6 minutes;
e) Spraying 20-60%) of the Spray Solution, of step (c), to the mixture of step (d);
f) Operating the Roto granulator such that the rotor's movement and the Pan's movement are in a direction opposite to each other, to get agglomerates in size range of75μ-200u;
g) Charging completely the Mixture-B in the Roto Granulator of step (f) and mixing
both the mixtures by operating the Roto granulator for 3-5 minutes such that the pan
is at a speed of 20-200 rpm and the rotor is at a speed of 500-3000 rpm, keeping
movement of the rotor and that of the pan in the same direction, for layering the
agglomerates;
h) Spraying the remaining quantity (40-80%) of the Spray Solution to the agglomerates of step (g), followed by mixing for another 10-15 minutes to get granules in size range of 100μ-1000μ;
i) Drying the granules of step (h) to get granules containing moisture content less than 0.5%;
j) Sieving the dried granules of step (i) to get 95-99% w/w yield;

k) Conditioning the resulting granules obtained in step (j), by passing the granules through an air chamber to get chemically stable synergistic herbicidal composition.
These granules are tested for the required quality specifications and packed in desired packing. The granules with the incorporation of solid adjuvants, by proper choice, enjoy all the formulation advantages.
The following examples are cited to illustrate but not to restrict the scope of the present invention. Parts and percentages are by weight unless otherwise specified.

EXAMPLE -1
Preparation of a composition containing Metsulfuron methyl active 5% + Sulfosulfuron active 75%[80%w/w]:
The following ingredients were blended to form a premix.
Weight percent
5.155
78.948
3.000
6.000
0.500
0.500
005.897
100.000
Premix formulation
Metsulfuron methyl Technical (purity 97%) Sulfosulfuron Technical (purity 95%) Stabilizer (Hexamethylene tetramine) Polyoxyethylene Sorbitan Fatty Acid ester Wetting & dispersing agent Anti-foaming agent (Rhodorsil 426-R) Filler
The above said chemically stable synergistic herbicidal composition can be prepared by following process:
Mixture-A was prepared by blending, milling and post blending of 5.155 gm Metsulfuron Methyl Technical, 25 gm of Sulfosulfuron Technical and 3gm of filler. Another Mixture-B was prepared by blending, milling and post blending of 53.948 gm of Sulfosulfuron technical with 3 gm Hexamethylene tetramine, 0.50gm wetting and dispersing agent, and 2.897 gm of filler. A spray solution was made by mixing 6gm Polyoxyethylene Sorbitan Fatty Acid ester with 0.5 gm defoamer and 13.5gm water.
Mixture-A, 33.155gm, was then charged in a Roto Granulator followed by mixing it for 5 minutes, then 8gm of spray solution was sprayed to the mixture in roto granulator. Roto Granulator was operated and then Mixture-B, 60.345gm, was charged in the roto granulator, followed by mixing these mixtures to obtain agglomerates. Then the balanced 12gm of spray solution was sprayed to the agglomerates followed by mixing them to obtain the granules of approximately 500u,-meter sizes. The granules obtained were dried, sieved and conditioned to get yield of more than 99.5 %. The product thus obtained is a chemically stable synergistic herbicidal composition.
EXAMPLE-2

Preparation of a composition containing Metsulfuron methyl active 10% + Sulfosulfuron active 70%[80%W/W]:
The following ingredients were blended to form a premix.
Premix formulation Weight percent
Metsulfuron methyl Technical (purity 97%) 10.309
Sulfosulfuron Technical (purity 95%) 73.685
Stabilizer (Hexamethylene tetramine) 3.000
Polyoxyethylene Sorbitan Fatty Acid ester 4.000
Wetting & dispersing agent 2.000
Anti-foaming agent (Rhodorsil 426-R) 0.500
Filler 006.506
100.000 The above said chemically stable synergistic herbicidal composition can be prepared by following process:
Mixture-A was prepared by blending, milling and post blending of 10.309gm Metsulfuron Methyl Technical, 25gm of Sulfosulfuron Technical and 4gm of filler. Another Mixture-B was prepared by blending, milling and post blending of 48.685gm of Sulfosulfuron technical with 3 gm Hexamethylene tetramine, 2.0gm wetting and dispersing agent, and 2.506gm of filler. A spray solution was made by mixing 4gm Polyoxyethylene Sorbitan Fatty Acid ester with 0.5 gm defoamer and 20.5gm water.
Mixture-A, 39.309gm, was then charged in a Roto Granulator followed by mixing it for 5 minutes, then 12gm of spray solution was sprayed to the mixture in roto granulator. Roto Granulator was operated and then Mixture-B, 56.191 gm, was charged in the roto granulator, followed by mixing these mixtures to obtain agglomerates. Then the balanced 13gm of spray solution was sprayed to the agglomerates followed by mixing them to obtain the granules of approximately 700μ-meter sizes. The granules obtained were dried, sieved and conditioned to get yield of more than 99.5 %. The product thus obtained is a chemically stable synergistic herbicidal composition.
EXAMPLE-3
Preparation of a composition containing Metsulfuron methyl active 7.5% + Sulfosulfuron active 75% [82.5% W/W]:
The following ingredients were blended to form a premix.
Premix formulation Weight percent
Metsulfuron methyl Technical (purity 97%) 7.732
Sulfosulfuron Technical (purity 95%) 78.948
Stabilizer (Hexamethylene tetramine) 4.000
Polyoxyethylene Sorbitan Fatty Acid ester 3.000
Wetting & dispersing agent 3.000
Anti-foaming agent (Rhodorsil 426-R) 0.500
Filler 002.820
100.000

The above said chemically stable synergistic herbicidal composition can be prepared by following process:
Mixture-A was prepared by blending, milling and post blending of 7.732gm Metsulfuron Methyl Technical, 30gm of Sulfosulfuron Technical and 2gm of filler. Another Mixture-B was prepared by blending, milling and post blending of 48.948gm of Sulfosulfuron technical with 4gm Hexamethylene tetramine, 3.0gm wetting and dispersing agent, and 0.820gm of filler. A spray solution was made by mixing 3gm Polyoxyethylene Sorbitan Fatty Acid ester with 0.5 gm defoamer and 26.5gm water.
Mixture-A, 39.732gm, was then charged in a Roto Granulator followed by mixing it for 5 minutes, then 15gm of spray solution was sprayed to the mixture in roto granulator. Roto Granulator was operated and then Mixture-B, 56.768gm, was charged in the roto granulator, followed by mixing these mixtures to obtain agglomerates. Then the balanced 15gm of spray solution was sprayed to the agglomerates followed by mixing them to obtain the granules of approximately 800μ-meter sizes. The granules obtained were dried, sieved and conditioned to get yield of more than 99.5 %. The product thus obtained is a chemically stable synergistic herbicidal composition.
EXAMPLE-4
Preparation of a composition containing Metsulfuron methyl active 5% + Sulfosulfuron active 70% [75% WAV]:
The following ingredients were blended to form a premix.
Premix formulation Weight percent
Metsulfuron methyl Technical (purity 97%) 5.155
Sulfosulfuron Technical (purity 95%) 73.685
Stabilizer (Hexamethylene tetramine) 2.750
Polyoxyethylene Sorbitan Fatty Acid ester 4.000
Wetting & dispersing agent 1.500
Anti-foaming agent (Rhodorsil 426-R) 0.500
Filler 012.410
100.000 The above said chemically stable synergistic herbicidal composition can be prepared by following process:
Mixture-A was prepared by blending, milling and post blending of 5.155gm Metsulfuron Methyl Technical, 40gm of Sulfosulfuron Technical and 6.0gm of filler. Another Mixture-B was prepared by blending, milling and post blending of 33.685gm of Sulfosulfuron technical with 2.750gm Hexamethylene tetramine, 1.50gm wetting and dispersing agent, and 6.410gm of filler. A spray solution was made by mixing 4.0gm Polyoxyethylene Sorbitan Fatty Acid ester with 0.5 gm defoamer and 30.5 Ogm water.
Mixture-A, 51.155gm, was then charged in a Roto Granulator followed by mixing it for 5 minutes, then 15gm of spray solution was sprayed to the mixture in roto granulator. Roto Granulator was operated and the Mixture-B, 44.345gm, was charged in the roto granulator, followed by mixing these mixtures to obtain agglomerates. Then the balanced 20gm of spray solution was sprayed to the agglomerates followed by mixing them to obtain the granules of approximately 1000μ-meter sizes. The granules obtained were dried, sieved and conditioned to

get yield of more than 99.5 %. The product thus obtained is a chemically stable synergistic herbicidal composition.
EXAMPLE - 5
Preparation of a composition containing Metsulfuron methyl active 5.92% + Sulfosulfuron active 75% [80.92% W/W]:
The following ingredients were blended to form a premix.
Premix formulation Weight percent
Metsulfuron methyl Technical (purity 97%) 6.103
Sulfosulfuron Technical (purity 95%) 78.948
Stabilizer (Hexamethylene tetramine) 3.500
Polyoxyethylene Sorbitan Fatty Acid ester 4.000
Wetting & dispersing agent 2.000
Anti-foaming agent (Rhodorsil 426-R) 0.500
Filler 004.949
100.000 The above said chemically stable synergistic herbicidal composition can be prepared by following process:
Mixture-A was prepared by blending, milling and post blending of 6.103gm Metsulfuron Methyl Technical, 25gm of Sulfosulfuron Technical and 2.0gm of filler. Another Mixture-B was prepared by blending, milling and post blending of 53.948gm of Sulfosulfuron technical with 3.500gm Hexamethylene tetramine, 2.0gm wetting and dispersing agent, and 2.949gm of filler. A spray solution was made by mixing 4.0gm Polyoxyethylene Sorbitan Fatty Acid ester with 0.5 gm defoamer and 25.50gm water.
Mixture-A, 33.103gm, was then charged in a Roto Granulator followed by mixing it for 5 minutes, then 10gm of spray solution was sprayed to the mixture in roto granulator. Roto Granulator was operated and then Mixture-B, 62.397gm, was charged in the roto granulator, followed by mixing these mixtures to obtain agglomerates. Then the balanced 20gm of spray solution was sprayed to the agglomerates followed by mixing them to obtain the granules of approximately 750μ.-meter sizes. The granules obtained were dried, sieved and conditioned to get yield of more than 99.5 %. The product thus obtained is a chemically stable synergistic herbicidal composition.
EXAMPLE-6
Preparation of a composition containing Metsulfuron methyl active 5% + Sulfosulfuron active 75% [80% W/W]:
The following ingredients were blended to form a premix.
Premix formulation Weight percent
Metsulfuron methyl Technical (purity 95%) 5.264
Sulfosulfuron Technical (purity 97%) 77.320
Stabilizer (Hexamethylene tetramine) 1.000

Polyoxyethylene Sorbitan Fatty Acid ester 2.500
Wetting & dispersing agent 6.250
Anti-foaming agent (Rhodorsil 426-R) 0.200
Filler 007.466
100.000 The above said chemically stable synergistic herbicidal composition can be prepared by following process:
Mixture-A was prepared by blending, milling and post blending of 5.260gm Metsulfuron Methyl Technical, 25gm of Sulfosulfiiron Technical and 2.0gm of filler. Another Mixture-B was prepared by blending, milling and post blending of 52.320gm of Sulfosulfiiron technical with l.OOOgm Hexamethylene tetramine, 6.250gm wetting and dispersing agent, and 5.466gm of filler. A spray solution was made by mixing 2.5gm Polyoxyethylene Sorbitan Fatty Acid ester with 0.2 gm defoamer and 17.30gm water.
Mixture-A, 32.264gm, was then charged in a Roto Granulator followed by mixing it for 5 minutes, then 8gm of spray solution was sprayed to the mixture in roto granulator. Roto Granulator was operated and then Mixture-B, 65.036gm, was charged in the roto granulator, followed by mixing these mixtures to obtain agglomerates. Then the balanced 12gm of spray solution was sprayed to the agglomerates followed by mixing them to obtain the granules of approximately 600μ-meter sizes. The granules obtained were dried, sieved and conditioned to get yield of more than 99.5 %. The product thus obtained is a chemically stable synergistic herbicidal composition.
EXAMPLE-7
Preparation of a composition containing Metsulfuron methyl active 5% + Sulfosulfiiron active 70%[75%W/W]:
The following ingredients were blended to form a premix.
Premix formulation Weight percent
Metsulfuron methyl Technical (purity 95%) 5.264
Sulfosulfiiron Technical (purity 97%) 72.165
Stabilizer (Hexamethylene tetramine) 0.500
Polyoxyethylene Sorbitan Fatty Acid ester 3.000
Wetting & dispersing agent 1.000
Anti-foaming agent (Rhodorsil 426-R) 0.100
Filler 017.971
100.000 The above said chemically stable synergistic herbicidal composition can be prepared by following process:
Mixture-A was prepared by blending, milling and post blending of 5.264gm Metsulfuron Methyl Technical, 20m of Sulfosulfiiron Technical and 7.0gm of filler. Another Mixture-B was prepared by blending, milling and post blending of 52.165gm of Sulfosulfiiron technical with 0.5gm Hexamethylene tetramine, l.Ogm wetting and dispersing agent, and 10.971gm of filler. A spray solution was made by mixing 3.0gm Polyoxyethylene Sorbitan Fatty Acid ester with 0.1 gm defoamer and 6.90gm water.

Mixture-A, 32.264gm, was then charged in a Roto Granulator followed by mixing it for 5 minutes, then 4gm of spray solution was sprayed to the mixture in roto granulator. Roto Granulator was operated and then Mixture-B, 64.636gm, was charged in the roto granulator, followed by mixing these mixtures to obtain agglomerates. Then the balanced 6gm of spray solution was sprayed to the agglomerates followed by mixing them to obtain the granules of approximately 100μ-meter sizes. The granules obtained were dried, sieved and conditioned to get yield of more than 99.5 %. The product thus obtained is a chemically stable synergistic herbicidal composition.
EXAMPLE-8
Preparation of a composition containing Metsulfuron methyl active 7% + Sulfosulfuron active 70% [77% WAV]:
The following ingredients were blended to form a premix.
Premix formulation Weight percent
Metsulfuron methyl Technical (purity 95%) 7.369
Sulfosulfuron Technical (purity 97%) 72.165
Stabilizer (Hexamethylene tetramine) 0.750
Polyoxyethylene Sorbitan Fatty Acid ester 5.000
Wetting & dispersing agent 7.000
Anti-foaming agent (Rhodorsil 426-R) 0.150
Filler 007.566
100.000 The above said chemically stable synergistic herbicidal composition can be prepared by following process:
Mixture-A was prepared by blending, milling and post blending of 7.369gm Metsulfuron Methyl Technical, 30m of Sulfosulfuron Technical and 3.0gm of filler. Another Mixture-B was prepared by blending, milling and post blending of 42.165gm of Sulfosulfuron technical with 0.75gm Hexamethylene tetramine, 7.0gm wetting and dispersing agent, and 4.566gm of filler. A spray solution was made by mixing 5.0gm Polyoxyethylene Sorbitan Fatty Acid ester with 0.15 gm defoamer and 24.850gm water.
Mixture-A, 40.369gm, was then charged in a Roto Granulator followed by mixing it for 5 minutes, then 6gm of spray solution was sprayed to the mixture in roto granulator. Roto Granulator was operated and then Mixture-B, 54.48 lgm, was charged in the roto granulator, followed by mixing these mixtures to obtain agglomerates. Then the balanced 24gm of spray solution was sprayed to the agglomerates followed by mixing them to obtain the granules of approximately 1000μ-meter sizes. The granules obtained were dried, sieved and conditioned to get yield of more than 99.5 %. The product thus obtained is a chemically stable synergistic herbicidal composition.
EXAMPLE-9

Preparation of a composition containing Metsulfuron methyl active 7% + Sulfosulfuron active 75% [82% W/W]:
The following ingredients were blended to form a premix.
Premix formulation Weight percent
Metsulfuron methyl Technical (purity 95%) 7.369
Sulfosulfuron Technical (purity 97%) 72.320
Stabilizer (Hexamethylene tetramine) 1.250
Polyoxyethylene Sorbitan Fatty Acid ester 4.500
Wetting & dispersing agent 6.000
Anti-foaming agent (Rhodorsil 426-R) 0.200
Filler 003.361
100.000 The above said chemically stable synergistic herbicidal composition can be prepared by following process:
Mixture-A was prepared by blending, milling and post blending of 7.369gm Metsulfuron Methyl Technical, 35gm of Sulfosulfuron Technical and 2.0gm of filler. Another Mixture-B was prepared by blending, milling and post blending of 42.320gm of Sulfosulfuron technical with 1.25gm Hexamethylene tetramine, 6.0gm wetting and dispersing agent, and 1.361gm of filler. A spray solution was made by mixing 4.5gm Polyoxyethylene Sorbitan Fatty Acid ester with 0.20 gm defoamer and 15.30gm water.
Mixture-A, 44.369gm, was then charged in a Roto Granulator followed by mixing it for 5 minutes, then 5gm of spray solution was sprayed to the mixture in roto granulator. Roto Granulator was operated and then Mixture-B, 50.93 lgm, was charged in the roto granulator, followed by mixing these mixtures to obtain agglomerates. Then the balanced 15gm of spray solution was sprayed to the agglomerates followed by mixing them to obtain the granules of approximately 700μ-meter sizes. The granules obtained were dried, sieved and conditioned to get yield of more than 99.5 %. The product thus obtained is a chemically stable synergistic herbicidal composition.
EXAMPLE-10
Preparation of a composition containing Metsulfuron methyl active 10% + Sulfosulfuron active 70% [80% WAV]:
The following ingredients were blended to form a premix.
Premix formulation Weight percent
Metsulfuron methyl Technical (purity 95%) 10.526
Sulfosulfuron Technical (purity 97%) 72.165
Stabilizer (Hexamethylene tetramine) 1.000
Polyoxyethylene Sorbitan Fatty Acid ester 3.000
Wetting & dispersing agent 5.500
Anti-foaming agent (Rhodorsil 426-R) 0.250
Filler 007.559
100.000

The above said chemically stable synergistic herbicidal composition can be prepared by following process:
Mixture-A was prepared by blending, milling and post blending of 10.526gm Metsulfuron Methyl Technical, 20gm of Sulfosulfuron Technical and 3.0gm of filler. Another Mixture-B was prepared by blending, milling and post blending of 52.165gm of Sulfosulfuron technical with l.0gm Hexamethylene tetramine, 5.50gm wetting and dispersing agent, and 4.559gm of filler. A spray solution was made by mixing 3.0gm Polyoxyethylene Sorbitan Fatty Acid ester with 0.25 gm defoamer and 26.75gm water.
Mixture-A, 33.526gm, was then charged in a Roto Granulator followed by mixing it for 5 minutes, then l0gm of spray solution was sprayed to the mixture in roto granulator. Roto Granulator was operated and then Mixture-B, 63.224gm, was charged in the roto granulator, followed by mixing these mixtures to obtain agglomerates. Then the balanced 20gm of spray solution was sprayed to the agglomerates followed by mixing them to obtain the granules of approximately 900μ-meter sizes. The granules obtained were dried, sieved and conditioned to get yield of more than 99.5 %. The product thus obtained is a chemically stable synergistic herbicidal composition.
EXAMPLE-11
Preparation of a composition containing Metsulfuron methyl 10% + Sulfosulfuron 75% [85% W/W]:
The following ingredients were blended to form a premix.
Premix formulation Weight percent
Metsulfuron methyl Technical (purity 95%) 10.526
Sulfosulfuron Technical (purity 97%) 77.320
Stabilizer (Hexamethylene tetramine) 1.250
Polyoxyethylene Sorbitan Fatty Acid ester 2.000
Wetting & dispersing agent 6.750
Anti-foaming agent (Rhodorsil 426-R) 0.300
Filler 001.854
100.000 The above said chemically stable synergistic herbicidal composition can be prepared by following process:
Mixture-A was prepared by blending, milling and post blending of 10.526gm Metsulfuron Methyl Technical, 30gm of Sulfosulfuron Technical and 1 .0gm of filler. Another Mixture-B was prepared by blending, milling and post blending of 47.320gm of Sulfosulfuron technical with 1.25gm Hexamethylene tetramine, 6.75gm wetting and dispersing agent, and 0.854gm of filler. A spray solution was made by mixing 2.0gm Polyoxyethylene Sorbitan Fatty Acid ester with 0.30 gm defoamer and 17.70gm water.
Mixture-A, 41.526gm, was then charged in a Roto Granulator followed by mixing it for 5 minutes, then 7gm of spray solution was sprayed to the mixture in roto granulator. Roto Granulator was operated and then Mixture-B, 56.174gm, was charged in the roto granulator, followed by mixing these mixtures to obtain agglomerates. Then the balanced 13gm of spray solution was sprayed to the agglomerates followed by mixing them to obtain the granules of approximately 700μ-meter sizes. The granules obtained were dried, sieved and conditioned to

get yield of more than 99.5 %. The product thus obtained is a chemically stable synergistic herbicidal composition.
EXAMPLE -12
Preparation of a composition containing Metsulfuron methyl 10% + Sulfosulfuron 80% [90% W/W]:
The following ingredients were blended to form a premix.
Premix formulation Weight percent
Metsulfuron methyl Technical (purity 95%) 10.526
Sulfosulfuron Technical (purity 97%) 82.475
Stabilizer (Hexamethylene tetramine) 1.500
Polyoxyethylene Sorbitan Fatty Acid ester 1.000
Wetting & dispersing agent 0.000
Anti-foaming agent (Rhodorsil 426-R) 0.300
Filler 004.199
100.000 The above said chemically stable synergistic herbicidal composition can be prepared by following process:
Mixture-A was prepared by blending, milling and post blending of 10.526gm Metsulfuron Methyl Technical, 40gm of Sulfosulfuron Technical and 2.0gm of filler. Another Mixture-B was prepared by blending, milling and post blending of 42.475gm of Sulfosulfuron technical with 1.5gm Hexamethylene tetramine, and 2.199gm of filler. A spray solution was made by mixing l.0gm Polyoxyethylene Sorbitan Fatty Acid ester with 0.30 gm defoamer and 13.70gm water. Mixture-A, 52.526gm, was then charged in a Roto Granulator followed by mixing it for 5 minutes, then 8gm of spray solution was sprayed to the mixture in roto granulator. Roto Granulator was operated and then Mixture-B, 46.174gm, was charged in the roto granulator, followed by mixing these mixtures to obtain agglomerates. Then the balanced 7gm of spray solution was sprayed to the agglomerates followed by mixing them to obtain the granules of approximately 400μ-meter sizes. The granules obtained were dried, sieved and conditioned to get yield of more than 99.5 %. The product thus obtained is a chemically stable synergistic herbicidal composition.
EXAMPLE -13
Preparation of a composition containing Metsulfuron methyl active 7% + Sulfosulfuron active 80% [87% W/W]:
The following ingredients were blended to form a premix.

Weight percent
7.369
82.475
2.000
3.000
4.000
0.300
000.856
100.000
Premix formulation
Metsulfuron methyl Technical (purity 95%) Sulfosulfuron Technical (purity 97%) Stabilizer (Hexamethylene tetramine) Polyoxyethylene Sorbitan Fatty Acid ester Wetting & dispersing agent Anti-foaming agent (Rhodorsil 426-R) Filler
The above said chemically stable synergistic herbicidal composition can be prepared by following process:
Mixture-A was prepared by blending, milling and post blending of 7.369gm Metsulfuron Methyl Technical, 30gm of Sulfosulfuron Technical and 0.50gm of filler. Another Mixture-B was prepared by blending, milling and post blending of 52.475gm of Sulfosulfuron technical with 2gm Hexamethylene tetramine, 4.0gm wetting and dispersing agent, and .356gm of filler. A spray solution was made by mixing 3.0gm Polyoxyethylene Sorbitan Fatty Acid ester with 0.30 gm defoamer and 11.70gm water.
Mixture-A, 37.869gm, was then charged in a Roto Granulator followed by mixing it for 5 minutes, then 7gm of spray solution was sprayed to the mixture in roto granulator. Roto Granulator was operated and then Mixture-B, 58.83 lgm, was charged in the roto granulator, followed by mixing these mixtures to obtain agglomerates. Then the balanced 8gm of spray solution was sprayed to the agglomerates followed by mixing them to obtain the granules of approximately 550μ-meter sizes. The granules obtained were dried, sieved and conditioned to get yield of more than 99.5 %. The product thus obtained is a chemically stable synergistic herbicidal composition.
EXAMPLE-14
Preparation of a composition containing Metsulfuron methyl active 5% + Sulfosulfuron active 80% [85% WAV]:
The following ingredients were blended to form a premix.
Premix formulation Weight percent
Metsulfuron methyl Technical (purity 95%) 5.264
Sulfosulfuron Technical (purity 97%) 82.475
Stabilizer (Hexamethylene tetramine) 2.000
Polyoxyethylene Sorbitan Fatty Acid ester 2.000
Wetting & dispersing agent 6.000
Anti-foaming agent (Rhodorsil 426-R) 0.150
Filler 002.111
100.000 The above said chemically stable synergistic herbicidal composition can be prepared by following process:
Mixture-A was prepared by blending, milling and post blending of 5.264gm Metsulfuron Methyl Technical, 25gm of Sulfosulfuron Technical and 2.0gm of filler. Another Mixture-B was prepared by blending, milling and post blending of 57.475gm of Sulfosulfuron technical with

2.0gm Hexamethylene tetramine, 6.0gm wetting and dispersing agent, and 0. 111gm of filler. A spray solution was made by mixing 2.0gm Polyoxyethylene Sorbitan Fatty Acid ester with 0.15 gm defoamer and 22.85gm water.
Mixture-A, 32.264gm, was then charged in a Roto Granulator followed by mixing it for 5 minutes, then l0gm of spray solution was sprayed to the mixture in roto granulator. Roto Granulator was operated and then Mixture-B, 65.586gm, was charged in the roto granulator, followed by mixing these mixtures to obtain agglomerates. Then the balanced 15gm of spray solution was sprayed to the agglomerates followed by mixing them to obtain the granules of approximately 900μ-meter sizes. The granules obtained were dried, sieved and conditioned to get yield of more than 99.5 %. The product thus obtained is a chemically stable synergistic herbicidal composition.
EXAMPLE -15
Evaluation of the synergistic herbicidal effect of the Metsulfuron methyl plus Sulfosulfuron combination can be established by using any composition prepared by the process described in the above examples 1-14. For these evaluations one or more of the compositions prepared in the examples are used here.
The herbicides Metsulfuron methyl and Sulfosulfuron were evaluated alone and in combination with each other at varying dose rates. All the treatments were applied as spray using 250 litres of water per hectare on wheat field. The experiment was laid out in Randomised Block Design with 11 treatments and replicated thrice. The various dose rates used are shown in following Tables 1 and 2.
Table 1: Synergistic Effect of varying quantities of Metsulfuron methyl active content with constant Sulfosulfuron active content on Broad Leaf variety and grasses (%)

Sr. No. Metsulfuron
methyl (a.i.
ingm) Sulfosulfuron (a.i. in gm) % Weed kill with respect to. control plot after 60 days
Broad Leaf (Rumex) Grasses (Phalaris minor)
1. 1.6 0.0 96-98 0
2. 1.4 10.125 90-94 96-98
3. 1.2 10.125 86-90 96-98
4. 0.8 10.125 82-85 96-98
5. 0.6 10.125 78-80 96-98
6. 0.0 10.125 0 96-98
Results : From the above Table 1, it can be seen that the highest control of Broad leaf weeds is obtained by 1.6 gm of Metsulfuron methyl and control of grasses is obtained by 10.125 gm of Sulfosulfuron.

Table 2 : Synergistic Effect of varying quantities of Sulfosuifuron active content with/without Metsulfuron Methyl active content on Broad Leaf variety and
grasses (%)

Sr. No. Metsulfuron
methyl (a.i.
in gm) Sulfosuifuron (a.i. in gm) % Weed kill with respect to. control plot after 60 days
Broad Leaf (Rumex) Grasses {Phalaris minor)
1. 0.0 10.125 0 96-98
2. 0.6 10.125 78-80 96-98
3. 0.8 10.55 82-86 96-98
4. 0.8 11.0 86-90 96-98
5. 0.8 11.5 90-94 96-98
6. 0.8 12.0 96-98 96-98
7. 0.8 12.5 96-98 96-98
Results : From the above Table 2 it can be seen that the highest control of both Broad leaf varieties and grasses is obtained by two dose rates -0.8 gm Metsulfuron methyl + 12.0 gm Sulfosulfuron and 0.8 gm Metsulfuron methyl + 12.5 gm Sulfosulfuron.
Graph I: Efficacy of varying concentrations of Metsulfuron methyl 10.125 of Sulfosulfuron
on Broad Leaf Control

Varying concentration of Metsulfuron Methyl with 10.125gm of Sulfosuifuron (AI in gm)

Graph

II: Effect of adding varying concentrations of Sulfosulfuron in 0.8 gm of Metsulfuron methyl on Broad Leaf Control


Conclusion
As can be seen from the data shown in Tables 1 and 2 and Graphs I and II, the combination of Metsulfuron methyl 0.8 gm with Sulfosulfuron 12.0 gm demonstrates a synergistic herbicidal effect.

We claim:
A chemically stable synergistic herbicidal composition comprising Metsulfuron Methyl, active content, 5 to 10% by weight of composition, and, Sulfosulfuron, active content, 70 to 80% by weight of composition, with 1 to 20% w/w of inert fillers, 1.0 to 10% w/w of Polyoxyethylene Sorbitan Fatty Acid Ester along with 0.1 to 10% w/w of a stabilizer, 0.1 to 1% w/w of a defoamer and 0 to 10% w/w of wetting and dispersing agents.
A chemically stable synergistic herbicidal composition as claimed in claim 1, wherein Metsulfuron Methyl is 5-7% w/w of the said composition.
A chemically stable synergistic herbicidal composition as claimed in claim 1, wherein Sulfosulfuron is 73 to 78% w/w of the said composition.
A chemically stable synergistic herbicidal composition as claimed in claim 1, wherein Metsulfuron Methyl is 5% w/w of the said composition.
A chemically stable synergistic herbicidal composition as claimed in claim 1, wherein Sulfosulfuron is 75% w/w of the said composition.
A chemically stable synergistic herbicidal composition as claimed in claim 1, wherein Polyoxyethylene Sorbitan Fatty Acid Ester is Sorbitan Monooleate.
A chemically stable synergistic herbicidal composition as claimed in claim 1, wherein the inert filler is a mixture of Attapulgite 30-40% w/w and precipitated silica 60-70% w/w of the total inert filler.
A composition as claimed in any of the claims 1 to 7, wherein the stabilizer is ammonium sulphate.
A chemically stable synergistic herbicidal composition as claimed in any of the claims 1 to 8, wherein the stabilizer is hexamethylene tetramine.
.A chemically stable synergistic herbicidal composition as claimed in any of the claims 1 to 9, wherein the defoamer is Silicon Oil Derivative.
.A chemically stable synergistic herbicidal composition as claimed in any of the claims 1 to 10, wherein the defoamer is Rhodorsil 426-R.
. A chemically stable synergistic herbicidal composition as claimed in any of the above mentioned claims, wherein the said composition is prepared by a process comprising steps:
Preparing a Mixture-A in the following steps: (i) Pre blending 5-10% Metsulfuron Methyl active content, 20-40% of
Sulfosulfuron active content and 0.1-10% of inert filler; (ii) Milling the pre blend,

(iii) Post blending the milled mixture to get the Mixture-A;
Preparing a Mixture-B in the following steps:
(i) Pre blending 30-60% of sulfosulfuron active content, 0.1-10% Stabilizer, 0.01-
10% of inert filler, with 0-5% wetting and 0-l%dispersing agent; (ii) Milling the pre blend; (iii) Post blending the milled mixture to get the Mixture-B;
Making 10-40% w/w of the composition, a Spray Solution by mixing 10-100 parts Polyoxyethylene Sorbitan Fatty Acid Ester along with 1-10 parts defoamer and 50-500 parts water;
Charging completely the Mixture-A in a Roto Granulator, having a rotor and a pan, followed by mixing it with the help of the rotor for 4-6 minutes;
Spraying 20-60% of the Spray Solution, of step (c), to the mixture of step (d);
> Operating the Roto granulator such that the rotor's movement and the Pan's movement are in a direction opposite to each other, to get agglomerates in size range of 75μ- 200μ;
Charging completely the Mixture-B in the Roto Granulator of step (f) and mixing both the mixtures by operating the Roto granulator for 3-5 minutes such that the pan is at a speed of 20-200 rpm and the rotor is at a speed of 500-3000 rpm, keeping movement of the rotor and that of the pan in the same direction, for layering the agglomerates;
Spraying the remaining quantity (40-80%) of the Spray Solution to the agglomerates of step (g), followed by mixing for another 10-15 minutes to get granules in size range of 100μ-1000μ;
Drying the granules of step (h) to get granules containing moisture content less than 0.5%;
Sieving the dried granules of step (i) to get 95-99% w/w yield;
Conditioning the resulting granules obtained in step (i), by passing the granules through an air chamber to get chemically stable synergistic herbicidal composition.
. A process for preparation of a chemically stable synergistic herbicidal composition as claimed in claim 12 wherein Metsulfuron Methyl is 5-7% w/w of the composition.
.A process as claimed in claim 12, wherein Sulfosulfuron is 70-80% w/w of the composition.

, A process for preparation of a chemically stable synergistic herbicidal composition as claimed in claim 12, wherein Polyoxyethylene Sorbitan Fatty Acid Ester is Sorbitan Monooleate.
A process for preparation of a chemically stable synergistic herbicidal composition as claimed in claim 12, wherein, the inert filler is a mixture of Attapulgite 30-40% w/w and precipitated silica 60-70% w/w of the total inert filler.
A process for preparation of a chemically stable synergistic herbicidal composition as claimed in claim 12, wherein, the stabilizer is 0.5-3% w/w of the composition.
A process for preparation of a chemically stable synergistic herbicidal composition as claimed in claim 12, wherein the defoamer is 0.1-1.0% w/w of the composition.
A process for preparation of a chemically stable synergistic herbicidal composition as claimed in claim 12, wherein the stabilizer is ammonium sulphate.
A process for preparation of a chemically stable synergistic herbicidal composition as claimed in claim 12, wherein the stabilizer is hexamethylene tetramine.
A process for preparation of a chemically stable synergistic herbicidal composition as claimed in claim 12, wherein the defoamer is Silicon Oil Derivative.
A process for preparation of a chemically stable synergistic herbicidal composition as claimed in claim 12, wherein the defoamer is Rhodorsil 426-R.
A chemically stable synergistic herbicidal composition substantially as herein described and illustrated with reference to the text and the examples
Dated day of March 2004

M.B. TRIVEDI
Company Secretary For United Phosphorus Limited