FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
COMPLETE SPECIFICATION
(See Section 10)
"AN IMPROVED 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,
State of Gujarat, India,
INDIAN.
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 an improvement in the herbicidal composition disclosed and claimed in Patent Application No. 664/MUM/2004 granted as Patent No. IN206130, which is a divisional application of main patent application no. 15/MUM/2003, granted as patent no. IN 194225.
More particularly, the present invention relates to an improved herbicidal composition having superior storage stability, ease of processability and economic significance over the herbicidal composition of Patent No. IN206130.
Background and prior art :
A chemically stable and synergistic herbicidal composition that provides a combination of metsulfuron methyl and sulfosulfuron is disclosed and claimed in Patent No. IN201630.
Patent No. IN206130 discloses polyoxyethylene sorbitan fatty acid ester as an essential component of the compositions disclosed and claimed therein. The herbicidal composition claimed in claim 1 of Patent No. IN206130 comprises metsulfuron methyl active content 5 to 10 % by weight of composition, and sulfosulfuron active content 70 to 80 % by weight of composition along with 1 to 20% w/w of inert fillers, 1.0 to 10% w/w of polyoxyethylene sorbitan fatty acid ester and 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.
However, there exists a continuous need in the art for improved compositions having enhanced storage stability characteristics, ease of processability and economic significance. It has now been surprisingly found that the herbicidal composition of Patent No. IN206130 when made substantially free of polyoxyethylene sorbitan fatty acid ester is showing an improved storage stability, an ease of processability and an economic significance, without affecting the other advantages of the herbicidal composition claimed in Patent No. IN206130.


Object of invention:
Therefore, it is an object of the present invention to provide an improvement in the herbicidal composition as claimed in Patent No. IN206130.
It is a further object of the present invention to provide an improvement particularly in the storage stability, processability and economic significance of the herbicidal composition of Patent No. IN206130.
It is also an object of the present invention to provide an improvement over the herbicidal composition of Patent No. IN206130 without affecting its other advantages such as chemical stability, physico-chemical compatibility, synergism, no cross resistance and the like.
Summary of the invention:
According to an aspect of the present invention there is provided an improvement in and relating to a chemically stable synergistic herbicidal composition as claimed in Patent No. IN206130, said improved 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 25 % w/w of inert fillers, 0.1 to 10% w/w of a stabilizer, 0.1 to 1% w/w of a defoamer and 0 to 5.0 % w/w of wetting and 0 to 10.00 % dispersing and suspending agents, wherein said improved composition is substantially free of a polyoxyethylene sorbitan fatty acid ester.
Detailed Description:
Weed control using a synergistic combination of herbicides is an area of constant and continuous research and thereby contributes a number of different herbicidal compositions as an effective tool for improving the quality of the crops. The present inventors have now surprisingly found that the herbicidal composition of Patent No. IN206130 when made substantially free of polyoxyethylene sorbitan fatty acid ester is showing an improved storage stability, an ease of processability and an economic significance without affecting the other advantages of the herbicidal composition claimed in Patent No. IN206130. The storage stability of the herbicidal composition that is substantially free of polyoxyethylene sorbitan fatty acid ester is improved thereby increasing the shelf life and bioefficay of the invented herbicidal composition.


It has been found that the storage stability and processibility of the herbicidal composition that is substantially free of polyoxyethylene sorbitan fatty acid ester is increased with respect to the herbicidal composition as claimed in Patent No. IN206130.
The term substantially free of polyoxyethylene sorbitan fatty acid ester as used herein denotes a composition that comprises at least less than 1%, preferably less than 0.10% and more preferably less than 0.01% of polyoxyethylene sorbitan fatty acid ester. In a most preferred embodiment thereof, the term substantially free of polyoxyethylene sorbitan fatty acid ester denotes a composition that is completely devoid of polyoxyethylene sorbitan fatty acid ester.
The inert filler may be selected from precipitated silica, kaolin, bentonite, dolomite, Attapulgite, ammonium sulphate and the like or a mixture thereof. In a preferred embodiment, the inert filler is ammonium sulphate and / or a mixture of Attapulgite (30-40%) and precipitated silica (60-70%).
The stabilizer optionally present in the composition in a preferred embodiment is hexamethylene tetramine.
The defoamer is selected from silicone defoamers and the like. In a preferred embodiment, the defoamer is tallow soap, Rhodorsil 426R and / or a mixture thereof.
In another embodiment, the defoamer is a tallow soap derived from any of the suitable animal fat. As used herein, the tallow soap is typically an animal fat that conforms to certain predetermined criteria such as, for example, melting point. The industrial tallow commercially used contains fat derived from animals such as pigs. In another embodiment, tallow may be derived from mutton or beef.
The wetting agent is selected from sodium dialkyl naphthalene sulphonates, alkyl ethoxylates, ether sulphates and other such agents known in the art.
The dispersing and /or suspending agent is selected from sodium naphthalene sulphonate, sodium lignosulphonate, polycarboxylates and other such agents known in the art.


The improved herbicidal compositions of the present invention may be prepared by methods that are substantially disclosed in Patent No. IN 206130 wherein the said spray solution is prepared substantially free of polyoxyethylene sorbitan fatty acid ester.
The direct incorporation of polyoxyethylene sorbitan fatty acid ester during the premixing, grinding, post mixing or granulation stage during the formulation process is quite a cumbersome task. Due to the very nature of the Polyoxyethylene Sorbitan fatty acid ester its uniform distribution is the main difficulty during direct addition. Polyoxyethylene Sorbitan fatty acid ester if added in the premixing stage forms lumps with the other solid/ powder ingredients. The further step of feeding and grinding causes intensive sticking to the machine parts which causes further loss in yield. The resulting formulation has the formation of soft or hard lumps till the post blending operation thus providing a non-homogenous distribution of Polyoxyethylene Sorbitan fatty acid ester. It also causes multiple problems to the formulator viz-a-viz having number of processing problems, increase in manufacturing/batch cycle time and inconsistency of the process parameters and product characteristics. The final formulation is not easy to dry and does not yield the perfect, dry free flowing granules. The product obtained forms soft or sometimes even hard lumps during storage and transporation. The product in bulk storage is also capable of forming lumps. The formation of lumps and non-homogenous distribution finally affects the dispersibility and overall performance of the final granular product.. The granules obtained often appear to be soft, form lumps in bulk storage and are unable to retain the shape, size and hardness till the shelf-life of the product.
Even when the addition of Polyoxyethylene Sorbitan fatty acid ester was done by the preparation of spray solution to ensure uniform distribution of the Polyoxyethylene Sorbitan fatty acid ester through out the processing mixture yet the granules formed were found to be soft and lumpy. The product was found to be less stable in consistency in comparison to the product without Polyoxyethylene Sorbitan fatty acid ester.
More particularly, the compositions of the present invention may be prepared by a process comprising:
(a) preparing a first mixture by pre-blending 5 - 10 % metsulfuron methyl active content, 20 -
40 % of sulfosulfuron active content and 0.1 - 10 % of inert filler; milling said pre-blend
and post-blending the milled mixture to get said first mixture;


(b) preparing a second mixture by pre-blending 30 - 60 % of sulfosulfuron active content, 0.1 -10 % stabilizer, 0.01-15 % of inert filler, with 0-5 % wetting and 0 - 10 % dispersing and suspending agent; milling said pre-blend and post-blending the milled mixture to get said second mixture;
(c) preparing a spray solution being 10-40 % w/w of the composition by mixing 1-10 parts defoamer(s) and 50 - 500 parts water;
(d) charging completely said first mixture 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 said prepared 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 of 75 u - 200 u;
(g) charging completely said second mixture in the roto-granulator of step (f) and mixing said first and second mixtures by operating the roto-granulator for 3-5 minutes such that the pan is rotated 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 said prepared spray solution to the agglomerates of step (g), followed by mixing for another 10-15 minutes to get granules in size range of 100 u - 1000 \i;
(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; and
(k) conditioning the resulting granules obtained in step (j), by passing the granules through an air chamber to get chemically stable synergistic herbicidal composition.
The details of the invention, its objects and advantages are explained hereunder in greater detail in
relation to the following non-limiting exemplary illustrations.
Example A-1
The following ingredients were blended by the process outlined above to obtain a herbicidal
composition comprising Metsulfuron methyl 5 % + Sulfosulfuron 75 % + active content in granular
form with other ingredients.

SNo. Ingredient Component Amount (gm)
1 Active agent Sulfosulfuron of purity 98% 76.531
Metsulfuron methyl of purity 95% 5.264


2 Dispersant Sodium naphthalene sulfonate 2.500
Lignosulfonate 0.100
Potassium polycarboxylate 4.000
3 Wetting agent Sodium dialkyl naphthalene sulphonate 0.100
3EO alkyl (C12-C13) ether sulfate 4.200
4 Suspending agent Ethylene oxide-Propylene oxide 1.700
a- alkyl (C10-C16) -w - hydroxypoly (oxyethylene) mixture 0.100
5 Defoamer Tallow soap + Silicone defoamer 0.200
6 Filler Precipitated Silica 5.305
Total 100.000 gm
The above said chemically stable synergistic herbicidal composition was prepared by following process. A first mixture was prepared by blending, milling and post blending of 5.264 gm metsulfuron methyl technical, 40.000 gm of sulfosulfuron technical and 3.000 gm of filler. A second mixture was prepared by blending, milling and post blending of 36.531 gm of sulfosulfuron technical with 1.800 gm suspending agent comprising ethylene oxide-propylene oxide and a- alkyl (C10-C16) - co - hydroxypoly (oxyethylene) mixture, 4.300 gm wetting agent and 6.600 gm dispersant, and 2.305 gm of filler. A spray solution was made by mixing 0.200 gm defoamer comprising (1:1) tallow soap : silicone defoamer and 24.800 gm water. The first mixture was then charged in a roto-granulator followed by mixing it for 5 minutes, then 10.000 gm of spray solution was sprayed to the mixture in roto-granulator. The roto-granulator was operated and then said second mixture 51.536 gm was charged in the roto-granulator, followed by mixing these mixtures to obtain agglomerates. Then the balanced 15.000 gm of spray solution was sprayed to the agglomerates followed by mixing them to obtain the granules of approximately 500 micrometer sizes. The granules obtained were dried, sieved and conditioned to get yield of more than 99.5 %. The product thus obtained is an improved synergistic herbicidal composition having an enhanced storage stability and economic significance.
Example A - 2
The following ingredients were blended by the process outlined above to obtain a herbicidal composition comprising Metsulfuron methyl 5 % + Sulfosulfuron 75 % active content in granular form with other ingredients.


SNo. Ingredient Component Amount (gm)
Active agent Sulfosulfuron of purity 97% 77.320
1 Metsulfuron methyl of purity 95% 5.264
2 Dispersant Sodium naphthalene sulfonate 2.500
Lignosulfonate 0.100
Potassium polycarboxylate 4.000
3 Wetting agent Sodium dialkyl naphthalene sulphonate 3EO alkyl (C12-C13) ether sulfate 0.100
4.200
4 Suspending agent Ethylene oxide-Propylene oxide 1.700
a- alkyl (C10-C16) -co - hydroxypoly (oxyethylene) mixture 0.100
5 Stabilizer Hexamethylene tetramine 1.000
67 Defoamer Silicone defoamer 0.200
Filler Precipitated Silica 3.516
Total 100.0
The above said chemically stable synergistic herbicidal composition was prepared by following process. A first mixture was prepared by blending, milling and post blending of 5.264 gm metsulfuron methyl technical; 37.320 gm of sulfosulfuron technical and 2.000 gm of filler. A second mixture was prepared by blending, milling and post blending of 40.000 gm of sulfosulfuron technical with 1.000 gm hexamethylene tetramine, 1.800 gm suspending agent comprising ethylene oxide-propylene oxide and a- alkyl (C10-C16) -co - hydroxypoly (oxyethylene) mixture, 4.300 gm wetting agent and 6.600 gm dispersant, and 1.516 gm of filler. A spray solution was made by mixing 0.200 gm defoamer and 24.800 gm water.. The first mixture was then charged in a roto-granulator followed by mixing it for 5 minutes, then 12.000 gm of spray solution was sprayed to the mixture in roto-granulator. The roto-granulator was operated and then said second mixture 55.216 gm was charged in the roto-granulator, followed by mixing these mixtures to obtain agglomerates. Then the balanced 13.000 gm of spray solution was sprayed to the agglomerates followed by mixing them to obtain the granules of approximately 500 micrometer sizes. The granules obtained were dried, sieved and conditioned to get yield of more than 99.7 %. The product thus obtained is an improved synergistic herbicidal composition having an enhanced storage stability and economic significance.


Example A - 3
The following ingredients were blended by the process outlined above to obtain a herbicidal composition comprising Metsulfuron methyl 10 % + Sulfosulfuron 70 % active content in granular form with other ingredients.

SNo. Ingredient Component Amount (gm)
Active agent Sulfosulfuron of purity 97% 72.165
1 Metsulfuron methyl of purity 95% 10.526
Dispersant Sodium naphthalene sulfonate 2.000
2 Lignosulfonate 0.500
Potassium polycarboxylate 3.500
3 Wetting agent Sodium dialkyl naphthalene sulphonate 0.400
3EO alkyl (C12-C13) ether sulfate 3.600
4 Suspending agent Ethylene oxide-Propylene oxide 2.500
a- alkyl (C10-C16) - 00 - hydroxypoly (oxyethylene) mixture 0.300
5 6 Stabilizer Hexamethylene tetramine 2.000
Defoamer Tallow soap + Silicone defoamer \ 0.250
7 Filler Attapulgite + Precipitated Silica 2.259
Total 100.000 gm
The above said chemically stable synergistic herbicidal composition was prepared by following process. A first mixture was prepared by blending, milling and post blending of 10.526 gm metsulfuron methyl technical, 25.000 gm of sulfosulfuron technical and 2.000 gm of filler. A second mixture was prepared by blending, milling and post blending of 47.165 gm of sulfosulfuron technical with 2.000 gm hexamethylene tetramine, 2.800 gm suspending agent comprising ethylene oxide-propylene oxide and a- alkyl (C10-C16) w - hydroxypoly (oxyethylene) mixture, 4.000 gm wetting agent and 6.000 gm dispersant, and 0.259 gm of filler.. A spray solution was made by mixing 0.250 gm defoamer comprising (1:1) tallow soap : silicone defoamer and 34.750 gm water. The first mixture was then charged in a roto-granulator followed by mixing it for 5 minutes, then 20.000 gm of spray solution was sprayed to the mixture in roto-granulator. The roto-granulator was operated and then said second mixture 62.224 gm was charged in the roto-granulator, followed by mixing these mixtures to obtain agglomerates. Then the balanced 15.000 gm of spray solution was sprayed to the agglomerates followed by mixing them to obtain the


granules of approximately 500 micrometer sizes. The granules obtained were dried, sieved and conditioned to get yield of more than 99.5 %. The product thus obtained is an improved synergistic herbicidal composition having an enhanced storage stability and economic significance.
Example A - 4
The following ingredients were blended by the process outlined above to obtain a herbicidal composition comprising Metsulfuron methyl 7 % + Sulfosulfuron 70 % + active content in granular form with other ingredients.

SNo. Ingredient Component Amount (gm) —
1 Active agent Sulfosulfuron of purity 97% 72.165
Metsulfuron methyl of purity 95% 7.369 —
2 Wetting agent Sodium dialkyl naphthalene sulphonate 1.000
3EO alkyl (C12-C13) ether sulfate 4.000
3 4 Suspending agent Ethylene oxide-Propylene oxide 4.500
a- alkyl (C10-C16) -co - hydroxypoly (oxyethylene) mixture 1.000
Stabilizer Hexamethylene tetramine 1.500
5 Defoamer Silicone defoamer 0.300
6 Filler Precipitated Silica 8.166
Total 100.000 gm
The above said chemically stable synergistic herbicidal composition was prepared by following process. A first mixture was prepared by blending, milling and post blending of 7.369 gm metsulfuron methyl technical, 32.165 gm of sulfosulfuron technical and 6.000 gm of filler. A second mixture was prepared by blending, milling and post blending of 40.000 gm of sulfosulfuron technical with 1.500 gm hexamethylene tetramine, 5.500 gm suspending agent comprising ethylene oxide-propylene oxide and a- alkyl (C10-C16) -co - hydroxypoly (oxyethylene) mixture, 5.000 gm wetting agent and 2.166 gm of filler A spray solution was made by mixing 0.300 gm defoamer and 39.700 gm water. The first mixture was then charged in a roto-granulator followed by mixing it for 5 minutes, then 24.000 gm of spray solution was sprayed to the mixture in roto-granulator. The roto-granulator was operated and then said second mixture 54.166 gm was charged in the roto-granulator, followed by mixing these mixtures to obtain agglomerates. Then the balanced


16.000 gm of spray solution was sprayed to the agglomerates followed by mixing them to obtain the granules of approximately 600 micrometer sizes. The granules obtained were dried, sieved and conditioned to get yield of more than 99.7 %. The product thus obtained is an improved synergistic herbicidal composition having an enhanced storage stability and economic significance.
Example A - 5
The following ingredients were blended by the process outlined above to obtain a herbicidal composition comprising Metsulfuron methyl 5 % + Sulfosulfuron 75 % active content in granular form with other ingredients.

SNo. Ingredient Component Amount (gm)
1 Active agent Sulfosulfuron of purity 97% 77.320
Metsulfuron methyl of purity 95% 5.264
2 Dispersant Sodium naphthalene sulfonate 2.000
Lignosulfonate 0.500
Potassium polycarboxylate 4.000
3 Wetting agent Sodium dialkyl naphthalene sulphonate 0.500
3EO alkyl (C12-Q3) ether sulfate 4.500
4 Suspending agent Ethylene oxide-Propylene oxide 1.700
a- alkyl (C10-C16) -co - hydroxypoly (oxyethylene) mixture 0.200
5 Stabilizer Hexamethylene tetramine 1.000
6 Defoamer Silicone defoamer 0.200
7 ^ Filler Ammonium sulphate 2.816
Total
100.000 gm

The above said chemically stable synergistic herbicidal composition was prepared by following process. A first mixture was prepared by blending, milling and post blending of 5.264 gm metsulfuron methyl technical; 35.000 gm of sulfosulfuron technical and 1.816 gm of filler. A second mixture was prepared by blending, milling and post blending of 42.320 gm of sulfosulfuron technical with 1.000 gm hexamethylene tetramine, 1.900 gm suspending agent comprising ethylene oxide-propylene oxide and a- alkyl (C10-C16) -w - hydroxypoly (oxyethylene) mixture, 5.000 gm wetting agent and 6.500 gm dispersant, and 1.000 gm of filler. A spray solution was

made by mixing 0.200 gm defoamer and 29.800 gm water.. The first mixture was then charged in a roto-granulator followed by mixing it for 5 minutes, then 12.000 gm of spray solution was sprayed to the mixture in roto-granulator. The roto-granulator was operated and then said second mixture 57.720 gm was charged in the roto-granulator, followed by mixing these mixtures to obtain agglomerates. Then the balanced 18.000 gm of spray solution was sprayed to the agglomerates followed by mixing them to obtain the granules of approximately 500 micrometer sizes. The granules obtained were dried, sieved and conditioned to get yield of more than 99.9 %. The product thus obtained is an improved synergistic herbicidal composition having an enhanced storage stability and economic significance.
Example A- 6

SNo. Ingredient Component Amount (gm)
1 Active agent Sulfosulfuron of purity 98% 76.531
Metsulfuron methyl of purity 95% 5.264
Dispersant Sodium naphthalene sulfonate 2.500
Lignosulfonate Potassium polycarboxylate 0.100
2 4.000
Wetting agent Sodium dialkyl naphthalene sulphonate 0.100
3 3EO alkyl (C12-C13) ether sulfate 4.200
4 Suspending agent Ethylene oxide-Propylene oxide 1.700
a- alkyl (C10-C16) -co - hydroxypoly (oxyethylene) mixture 0.100
5 Defoamer Tallow soap + Silicone defoamer 0.200
6 Filler Precipitated Silica 5.305
Total 100.000 gm
The dispersants, defoamers, wetting agents, suspending agent and filler is charged in the ribbon blender and blended till a homogeneous mixture is formed. Gradually the required quantity of Sulfosulfuron technical and Metsulfuron-methyl technical are added and blended to form a homogeneous mixture. The homogeneous mixture is micronised for the required particle size. The micronised material is charged into a post blender for post blending. The mixture is then charged in to a Granulator to form granules. The granules are dried in a dryer and sieved through a vibro screen using required sieve size.


Following examples G-1, G-2, G-6 and G-8 are taken from the herbicidal composition as claimed in Patent No. IN206130 for comparison. These examples provide for the compositions with POS (Polyoxyethylene sorbitan fatty acid ester)
EXAMPLES G-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.
Premix formulation Weight percent
Metsulfuron methyl Technical (purity 97%) 5.155
Sulfosulfuron Technical (purity 95%) 78.948
Stabilizer (Hexamethylene tetramine) 3.000
Polyoxyethylene Sorbitan Fatty Acid ester 6.000
Wetting & dispersing agent 0.500
Anti-foaming agent (Rhodorsil 426-R) 0.500
Filler 005.897
Total 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 5.155 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 500micrometer 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.


EXAMPLES G-2
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 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
Total 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, 56.191gm, 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 700micrometer 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.


EXAMPLES G-6
Preparation of a composition containing Metsulfuron methyl active 5% + Sulfosulfuron active 75% [80% 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%) 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 07.466
Total 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 Sulfosulfuron Technical and 2.0gm of filler. Another Mixture-B was prepared
by blending, milling and post blending of 52.320gm of Sulfosulfuron 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 600micrometer 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.


EXAMPLES G-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
Total 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 1000 micrometer sizes.


Improved consistency of the herbicidal composition
The granules for disintegration and material in suspension were tested as per the following procedure:
1 g of the granules was added to a measuring cylinder containing 100 ml of water. The cylinder was inverted through 180 degrees and back again for one full inversion, taking 2 seconds and the number of seconds for complete disintegration observed. The cylinder was then allowed to stand for 30 minutes, undisturbed, and a 10 ml sample taken from the centre of the cylinder and analyzed, gravimetrically, for the amount of solids present. This figure was then used to calculate the % of material in suspension after standing for this time. The results were compared to the formulation of Metsulfuron methyl + Sulfosulfuron with polyoxyethylene sorbitan fatty acid ester (POS). The results obtained were as follows:
Table -A Showing the disintegration and suspension of Metsulfuron methyl + Sulfosulfuron at 0 day and after 30 months of ambient storage.

s.No. ExampleNo. Disintegration of granules (seconds) % material in suspension
At 0 day After 30 months At 0 day After 30 months
1 A-l 8 10 56.2 68.2
2 A-2 10 10 55.7 66.9
3 A-3 8 9 56.4 67.2
4 A-4 11 10 54.7 65.4
5 A-5 9 12 56.2 68.9
6 A-6 10 11 54.5 64.3
7 G-l 35 48 41.1 44.1
8 G-2 30 45 43.5 45.3
9 G-6 24 38 40.7 40.1
10 G-8 25 52 42.6 44.9
The a jove results indicate the a idvantages of the product r. >roduced wit hout POS in this invention. In
addition it was noted that the product with POS was badly caked in the commercial pack, indicating a physical inconsistency of the product on storage.
It was noted that the sample of product with POS was much more softer than the sample of product without POS produced by the process of the present invention. At the low use rate of the product, the higher susceptibility for the product would lead to a higher availability in field use and a higher efficacy. The granules of the present invention are made to deliver the active ingredients incorporated therein, particularly to an aqueous environment.
An improved storage stable granular product according to the invention is non-lumpy granular form. It retains its shape and identity between about 90% to 100% of its original shape. For


example, shape retention and flowability is at least about 90%, preferably at least about 93%, and most preferably about 95% of its original shape and flowability. By "free-flowing" is meant that the granules are essentially free of caking or fusing of the granules and are freely pourable, as from one container to another. Over 90%, especially 95% of the granules, prior to sieving or screening, are of a suitable size such that further processing to alter the size of the granules is not required.
Hardness of Granules:
For hardness the product with POS was compared with the product without POS in respect of relative hardness (represents by five relative rating shown in Table - B).
Table -B Shows the hardness and tap density of Metsulfuron methyl + Sulfosulfuron
granules at 0 days and after 30 months of ambient storage:
s.No. ExampleNo. Hardness of granules *(rating) Tap density (g/cc)
At 0 day After 30 months At 0 day After 30 months
1 A-l 3 3 0.560 0.562
2 A-2 3 3 0.583 0.582
3 A-3 3 3 0.604 0.604
4 A-4 4 3 0.625 0.624
5 A-5 4 4 0.555 0.553
6 A-6 4 4 0.575 0.574
7 G-l 1 1 0.595 0.590
8 G-2 1 1 0.595 0.602
9 G-6 2 1 0.609 0.615
10 G-8 2 1 0.620 0.630
Note: * Relative rating for hardness of granules:
1 - Easily deformable in shape by hands;
2 - Readily crushable by hands;
3 - Crushable by little power by hands;
4 - Crushable by small power by hands;
5 - Difficult to crush;
The product with POS thereof exhibited a hardness that allowed easily and /or readily deformable and crushable by hands whereas the product without the POS exhibited a hardness that requires little and/or small power for crushing.
The comparison data of table A and B, revealed that Metsulfuron methyl + Sulfosulfuron granules without polyoxyethylene sorbitan fatty acid ester was more consistent than Metsulfuron methyl + Sulfosulfuron granules with polyoxyethylene sorbitan fatty acid ester under ambient condition of the storage even at the end of 30 months after preparation of samples.


From the description, one skilled in the art can easily ascertain the essential characteristics of this invention, and without departing from the spirit and scope thereof, can make various changes and modifications of the invention to adapt it to various usages and conditions.
Improved stability of the herbicidal composition
The storage stability of the compositions according the present invention being substantially free of polyoxyethylene sorbitan fatty acid ester was compared with the storage stability of compositions comprising polyoxyethylene sorbitan fatty acid ester.
Table-1 Comparison of active ingredient content before (0 day) and after (21 days) Accelerated Heat Stability(54 ± 1 °C) treatment for products with and without POS.

S.N Example No. (Sulfosulfuron Sulfosulfuron content Metsulfuron methyl
O. : + nftfr21 rnntfnt after
Sulf Metsulfu Oday % 0 day 21 %
osulf ron days degrada days degrad
uron methyl tion ation
G-l-(with POS) 75.350 74.600 0.995 5.180 5.130 1 0.965
A-l- (without
1 POS) 75 5 75.380 75.010 0.491 5.180 5.160 0.386
G-6- (with POS) 76.160 75.250 1.195 5.050 4.990 1.190
A-2- (without
2 POS) 75 5 76.010 75.560 0.590 5.060 5.040 0.395
G-8- (with POS) 70.850 69.500 1.905 7.200 7.030 2.360
A-4- (without
3 POS) 70 7i 70.800 69.980 1.158 7.240 7.140 1.380
G-2- (with POS) 70.050 69.010 1.485 10.25 10.050 1.950
A-3- (without
4 POS) 70 10 70.200 69.640 0.798 10.27 10.18 0.876
Note: G- granted application composition example number


A- addition application composition example number POS- polyoxyethylene sorbitan fatty acid ester
Conclusion ;
The above table -1 results show that the compositions according to the present invention being substantially free of polyoxyethylene sorbitan fatty acid ester was more stable in storage in comparison to the compositions comprising polyoxyethylene sorbitan fatty acid ester.
The confirmation of the above results were done by keeping the same samples at room temperature in different packs. This study was conducted to determine the storage stability and corrosion characteristics of Metsulfuron methyl + Sulfosulfuron granules with and without polyoxyethylene sorbitan fatty acid ester, at ambient temperature for a period of 2 years. The test substance was prepared as described in the above examples. The method followed was as per the CIPAC guidelines.
Eight pouches of the same composition as the commercial pouch (trilaminated aluminium pouch, packed into CFB box) and two extra pouches (for emergency purpose) having 1000 g test substance in each pouch were stored at ambient temperature for 30 months (6 months extra). One pouch of the test substance was drawn initially (0 day) and one at each sampling intervals (i.e. after 3, 6, 9, 12, 18, 24 and 30 months) and the test substance was evaluated for corrosion characteristics (perforation, darkening and leaking at the seam), appearance of the container (by visual : shape, colour and cracks if any), appearance of the test substance (colour and physical state), active ingredient content i) as Metsulfuron methyl and ii) as Sulfosulfuron, wettability (wetting time), wet sieve test (percentage of material retained on 200 BSS test sieve), dry sieve test (percentage of material passing through 120 BSS test sieve), dustiness (percentage of material passing through 200 BSS test sieve). Dispersibility (percentage of material dispesed in 1 % aqueous suspension), rate of dissolution and suspension/solution stability of Metsulfuron methyl + Sulfosulfuron granules with and without polyoxyethylene sorbitan fatty acid ester (referred as "test substance").


Corrosion Characteristics of Container : The container was examined for corrosion characteristics such as perforation, darkening and leaking at the seam.
Appearance of Container : Visual observations were made for shape, cracks and colour of the container.
Appearance of Test Substance - The colour of the test substance was recorded at room temperature by visual inspection and description of colour was reported qualitatively. The physical state of the test substance was recorded by visual inspection. The results were recorded in descriptive terms.
Wetting Time of the Material (CIPAC MT 53.3.1): A volume of 100 mL standard water D (prepared as per CIPAC MT 18.1.4) was taken into a beaker of 250 mL capacity. Different quantities of test substance were weighed from samples drawn at 0 day and after 3, 6, 9, 12, 18, 24 and 30 months of storage with care that it remained in a non-compact form. It was then added at once, by dropping on the water from a position level with the rim of the beaker, without undue agitation of the liquid surface and the stopwatch was started simultaneously. The time taken to the nearest second for complete wetting of the test substance was recorded as the wetting time.
Methodology for Wet Sieve Test (CIPAC MT 167)
a. Wetting of the Test Substance : Different quantities of test substance were weighed from
samples drawn at 0 day and after 3, 6, 9, 12, 18, 24 and 30 months of storage into separate beakers
of 250 mL capacity. A volume of 100 mL tap water (temperature 5-15 °C) was added to each
beaker and allowed to stand for 60 seconds. After 60 seconds, the slurry was stirred with a rubber
capped glass rod by hand at a rate of three to four revolutions per second for 30 seconds.
b. Wet Sieving
The above slurry was transferred quantitatively to the 200 BSS (75 um) test sieve. The residues in the beaker and glass rod were rinsed with water and the slurry on the sieve was washed with tap water using rubber hose at the flow rate of 4 to 5 lit/min. The washing was continued for 10 minutes. The water was directed on the sieve from the circumference of the sieve towards the centre of the sieve in a circular manner. About 2 - 5 cm distance was maintained between end of the rubber hose and the surface of the sieve. The residues were transferred quantitatively to a pre-weighed petri dish with a jet of distilled water from the wash bottle. The petri dish was dried to a constant mass in hot-air-oven at a temperature of 70 °C. After drying the residue, the petri dish was taken out from the oven, allowed to cool in a desiccator and residue was weighed (m).


c. Calculation
Material retained on 200 BSS test sieve (% m/m) was calculated using the following formula:
m
Material retained on 200 BSS test sieve (% m/m) = x 100
M
where,
m = Mass (g) of the dry residues
M = Mass (g) of the material taken for the test
Dry sieve test Methodology for Particle Size Distribution (CIPAC MT 170):
Sampling (CIPAC MT 166) A quantity of 200.012 g test substance was taken into a sufficiently large polyethylene bag, filling the bag upto one third of its capacity. The closed bag was turned end-over-end 10 times to mix the contents. The bag was kept on a large area a sample layer of about 1 cm thickness was made. The representative sample was drawn from five different positions of the sample layer.
Tap Density (CIPAC MT 169): Quantities of 80g test substance (taken from five different positions in the plastic bag) were weighed (M) into two separate beakers of 100 mL capacity. The samples were poured slowly into separate measuring cylinders of 250 mL capacity and the cylinders were placed in the dropping box one at a time. The upper part of the cylinder was grasped gently with the thumb and the forefinger of one hand. The cylinder was lifted to the full extent of its travel during one second. The thumb and the forefinger were released quickly from the cylinders before the beginning of the next second. This procedure of lifting and dropping was continued until the 50 counted drops were completed. The cylinder was allowed to fall once in every 2 seconds and the rotation of the cylinder at an arc of about 10° was made during each lifting. After completion of the 50 drops, the cylinder was immediately removed from the dropping box and the volume (V) of the test substance was recorded. The same procedure was repeated with the second cylinder. The tap / apparent density (D) was calculated using the following formula:
M
Apparent density (D, g/mL)=
V
Particle Size Distribution (Machine Sieving Procedure) : Before starting the particle size distribution, the mass (m) of the sample to be taken was calculated as below :


m = nxDx20g
where,
n = Number of sieves used
D = Apparent density (g/mL)
The nest of the sieves (125, 250, 355, 500, 850, 1000, 1204 and 1405 um) were stacked one on top
of the other in the correct order with the coarsest sieve with the lid at the top and the finest sieve
with at the bottom and mounted on the receiver pan. The calculated quantity of samples (say 100 g)
were weighed (by drawing from five different positions of the plastic bag) and transferred onto the
coarsest sieve (i.e. 1405 um). The lid was fitted to the nest of sieves and the set of sieves was kept
in the sieving machine. The sieving machine was started and run for a period of 5 minutes. After 5
minutes, the nest of sieves was removed from the machine and allowed to stand for a period of 2
minutes to enable the airborne particle to settle. Then the lid was taken out and each of the sieves
were inverted over separate sheets of paper, the side of the sieve frame was tapped and the
uppermost surface was carefully brushed. The sieves were then reversed and brushed to dislodge the
loose particles adhering to the sieves. The individual mass of the test substance retained on each
sieve was recorded (gx, gm).
Calculation : The residue rx on each sieve was calculated as below:
gx
rx(%m/m) = —x 100
m
where,
gx = The mass (g) of the material retained on the sieve m = The mass (g) of the material taken for test
The sum of residues (Rx) was calculated on all the sieves (by summation of the residue rx on sieve with the residues on all subsequent coarser sieves summed) as below:
n
Rx = £ rx % m/m
x The particle size distribution of the test substance was specified by the range [xi, X2] of two sieves where Rx > 90% and Rx < 10%.


Dustiness (CIPAC MT 171) is defined as the property of a granular product to liberate dust into the air when handled under specified conditions. These conditions are related to typical handling in agriculture practice (i.e. measuring out and pouring the product into the spray tank).
Sampling (CIPAC MT 166) : A quantity of 200 g the test substance was taken into a sufficiently large polyethylene bag, filling about one third of the capacity of bag, separately. The closed bag was turned to end-over-end at least 10 times to mix the contents. The bag was kept on a large area to prepare a sample layer of about 1 cm thickness. The representative samples were drawn from five different position of the sample layer.
Determination of Dust: The filter disc was weighed to the nearest 0.1 mg before the start of the study (Wi) and kept on the filter plate of the glass filter. The glass filter was connected with tubing to an air flow meter and a vacuum pump. The glass filter was plugged into the circular fitting provided at the side of the measuring box. The vacuum pump was started and the airflow was adjusted to 15 liters per minute. Different quantities viz., 30.0004, 30.0012, 29.9994 g test substance were weighed (taken from five different positions in the plastic bag) in separate glass beakers. The content from one of the beaker was transferred to the pouring tube in a single action and the stopwatch was started simultaneously. The suction of the liberated air borne dust was continued for 60 seconds, to allow the dust to be collected on the filter disc. After 60 seconds, the vacuum pump was switched off and the filter disc was removed with a tweezer and weighed to the nearest 0.1 mg (W2). The same procedure was followed with the test substance in the other two remaining beakers.
Calculation : The dust content was calculated as difference of (W2 – W1) g.
The percentage dust content was calculated as (W2 – W1) / W x 100 The mean dust content of the test substance along with the standard deviation was reported
Dispersibility : Methodology for Spontaneity of Dispersion (Dispersibility) [CIPAC MT 174] Two tared glass beaker of 1000 mL capacity were filled upto 900 mL with standard water D each
(prepared as per CIPAC MT 18.1.4) at 20 ± 1 °C. The stirrer was centrally positioned in one of the
beakers in such a way that the bottom of the stirrer blades was 15 mm above the base of the beaker.


The stirrer was switched on and set at a speed of 300 rpm. Quantities of (approxiamately 9.0 g) test substance (m) was weighed and added to the two beakers containing 900 mL standard water D. Stirring was continued for 1 minute. The stirrer was then switched off and the suspension was allowed to stand undisturbed for 1 minute. Nine -tenth (810 mL) of suspension was withdrawn from both the beakers by means of vacuum pump within 30 to 60 seconds by maintaining the tip of the glass tube just below the falling level of the suspension, ensuring the suspension is not disturbed. The same procedure was repeated for another replication The solid material left in the remaining 90 mL of the suspension in both the beakers was determined gravimetrically (W), by evaporating the liquid suspension and drying at 65 °C till constant weight. The experiment was carried out in two replicates and the mean % dispersibility was calculated and reported.
Calculation : The dispersibility was calculated using the following formula :
10x(m-W)xl00
Dispersibility (%) =
9 xm
Where,
W = Mass (g) of the residue after drying m = Mass (g) of the sample taken for the test
Methodology for Rate of Dissolution and Solution Stability (CIPAC MT 60)
A volume of 400 mL standard water D (prepared as per CIPAC MT 18.1.4) was taken into two separate beakers of 500 mL capacity. The water was stirred using magnetic stirrer at such a rate that the vortex produced extends to approximately half the depth of the liquid. Different quantities of test substance were weighed from samples drawn at 0 day and after 3, 6, 9, 12, 18, 24 and 30 months of storage and quickly transferred to the beakers and the stirring was continued for further 5 minutes. Then the stirring was stopped and the contents were allowed to settle and the nature of the residue left was recorded. The contents were stirred again to bring back any settled material into the suspension. A volume of 100 mL suspension was quickly transferred into a measuring cylinder of 100 mL capacity and the contents were allowed to stand at 20 °C for a period of 18 h. At the end of this period, the sample was examined for any suspended or sedimented material.


Table-2 - The results of storage stability and corrosion characteristic for 30 months of Metsulfuron methyl + Sulfosulfuron (5+ 75%) Granules with POS (i. e. example G-l) analysis are summarized below:
G-l
Sr Result/Storage period (months)
No. Parameters Oday 3 6 9 12 18 24 30
Corrosion Perforation No
Characteristics Darkening No
1 Leaking No
appearance of Shape Rectangular Silver
container Color
2 (Visual) Crack No
3 Appearance of the Test Substance Light creamish free flowing granule Creamish free flowing granule
4 A.I. Content (% w/w) a) Sulfosulfuron 75.3 5 75.30 75.00 74.70 74.25 73.65 73.05 72.54
b) Metsulfuron methyl 5.18 5.16 5.15 5.13 5.09 5.01 4.97 4.67
5 Wetting time (seconds) 15 15 15 15 17 16 18 18
6 Wet sieve test (retention on 200 BSS Test sieve) % By mass 100 % material passing through 200 BSS test sieve
7 Dry sieve test analysis (% granules lying between 500-1000 urn) 98.20 98.23 98.20 98.20 98.22 98.25 98.25 98.30
8 Dustiness (material passing through 200 BSS sieve) % by mass NIL NIL NIL NIL NIL NIL NIL NIL
9 Dispersibility (1% aq. suspension) % by mass 90.80 90.78 90.75 90.80 90.85 90.90 90.96 91.00
10. Rate of Dissolution and Solution Stability AtO h Opaque suspension with slight setting of particles (less than 1.0 mL) without any large particles
After 18h 3.0 mL of fine particulate sediments and 97.0 mL of suspension containing fine particles


Table -3 - The results of storage stability and corrosion characteristic for 30 months of Metsulfuron methyl + Sulfosulfuron (5+ 75%) Granules without POS (i. e. example A-l) analysis are summarized below:

Sr Result/Storage period (months)
No. Parameters Oday 3 6 9 12 18 24 30
Corrosion Perforation No
Characteristics Darkening No
1 Leaking No
appearance of Shape Rectangular
container Color Silver
2 (Visual) Crack No
3 Appearance of Substance the Test> w/w) n 75.38 75.3' Off- white free flowing granules
4 A.I. Content (°A a) Sulfosulfuro I 75.28 75.01 74.60 74.19 73.56 73.08
b) Metsulfuron methyl 5.18 5.18 12 5.17 ; 5.17 1 5.16 5.09 1 5.01 4.94
5 Wetting time (seconds) 12 12 12 13 14 | 14 14
6 Wet sieve test (retention on 200 BSS Test sieve) % by mass 100 % passing through 200 BSS sieve
7 Dry sieve test analysis (% granules lying between 500-1000 urn) 97.30 97.3 0 ) 97.30 97.30 97.35 97.35 97.35 97.40
8 Dustiness (material passing theough 200 BSS sieve) (% by mass 0.10 0.1C 0.10 0.15 0.15 0.15 0.15 0.15
9 Dispersibility (l%aq. suspension) % by mass 92.50 92.55 92.58 92.59 92.60 92.60 92.61 92.64
Rate of Dissolution and Solution Stability At Oh Opaque suspension with slight setting of particles (less than 1.0 mL) without any large particles
10. After 18 h 2.0 mL of fine particulate sediments and 98.0 mL of suspension containing fine particles

Table -4 - The results of storage stability and corrosion characteristic for 30 months of Metsulfuron methyl + Sulfosulfuron (5+ 75%) Granules with POS (i. e. example G-6) analysis are summarized below:

G- 6
Sr Parameters Result/Storage period (months)
No. Oday 3 6 9 12 18 24 30
Corrosion Characteristics Perforation No
Darkening No
1 Leaking - - - — No
appearance of Shape Rectangular
container (Visual) Color Silver
2 Crack No
3 Appearance of the Test Substance Off white free flowing granule Light creamish free flowing granule
4 A.I. Content (% w/w) a) Sulfosulfuron 76.16 76.00 75.70 75.35 74.90 74.58 74.01 73.47
b) Metsulfuron methyl 5.05 5.04 5.02 5.01 4.99 4.84 4.72 4.64
5 Wetting time (seconds) 14 14 14 15 15 15 16 16
67 Wet sieve test (retention on 200 BSS Test sieve) % By massDry sieve test analysis (% granules lying between 500-1000 urn) 100% material sassing through 20 0 BSS test sieve
98.50 98.52 98.50 98.50 98.48 98.46 98.40 98.50
8 Dustiness (material passing through 200 BSS sieve) % by mass 0.10 0.10 0.10 0.11 0.11 0.10i 012 0.12
9 Dispersibility (1% aq. suspension) % by mass 91.09 91.08 91.07 91.07 91.06 91.04Ii 91.05 91.05
10. Rate of Dissolution and Solution Stability At Oh Opaque suspension with slight setting of particles (less mL) without any large particles than 1.0
After 18h 2.8 mL of fine particulate sediments and 97.2 mL of su containing fine particles spension

Table - 5 -The results of storage stability and corrosion characteristic for 30 months of Metsulfuron methyl + Sulfosulfuron (5+ 75%) Granules without POS (i. e. example A - 2) analysis are summarized below:

A-2
Sr Result/Storage period (months)
No. Parameters Oday 3 6 9 12 18 24 30
1 Corrosion Characteristics Perforation No
Darkening No
Leaking No
appearance of Shape Rectangular
2 container Color Silver
(Visual) Crack No
3 Appearance of the Test Substance Off- white free flowing granules
4 A.I. Content (% w/w) a) Sulfosulfuron 76.01 75.82 75.68 75.44 75.16 74.80 : 74.20 73.71
b) Metsulfuron methyl 5.06 5.06 \ 5.05 5.04 5.03 5.01 4.92 4.84
5 Wetting time (seconds) 10 1 10 10 11 11 11 11 12
6 Wet sieve test (retention on 200 BSS Test sieve) % by mass 100 % passing through 200 BSS sieve
7 Dry sieve test analysis (% granules lying between 500-1000 urn) 97.40 97.40 97.45 97.45 97.45 97.45 97.45| 97.41
8 Dustiness (material passing theough 200 BSS sieve) (% by mass 0.10 0.10 0.10 0.12 0.12 0.12 0.12 0.12
9 Dispersibility (1% aq. suspension) % by mass 92.80 92.81 92.81 92.84 92.80 92.80 92.80 92.84i
10. Rate of Dissolution and Solution Stability At Oh Opaque suspension with slight setting of particles (less \ than 1.0 mL) without any large particles
After 18h 2.0 mL of fine particulate sediments and 98.0 mL of suspension containing fine particles

Table - 6 -The results of storage stability and corrosion characteristic for 30 months of Metsulfuron methyl + Sulfosulfuron (7+ 70%) Granules with POS (i. e. example G-8) analysis are summarized below:G - 8
Sr No. Result/Storage period (months)
Parameters Oday 3 6 9 12 18 24 30
Corrosion Characteristics Perforation No
Darkening No
1 Leaking No
appearance of Shape Rectangular
2 container (Visual) Color Silver
Crack No
T Appearance of the Test Substance Light creamish free flowing granule Creamish free flowing granule
4 A.I. Content (% w/w) a) Sulfosulfuron 70.85 70.70 70.32 69.85 69.45 ! 69.15 68.98 68.40
b) Metsulfuron methyl 7.20 7.17 7.16 7.13 7.09 7.03 6.95 6.72
5 Wetting time (seconds) 14 14 ! 14 14 14 14 15 15
6 Wet sieve test (retention on 200 BSS Test sieve) % By mass 100 % material passing thr ough 200 BSS tes t sieve
7 Dry sieve test analysis (% granules lying between 500-1000 urn) 98.70 98.74 98.740 98.75 98.74 98.74 98.75 98.75
8 Dustiness (material passing through 200 BSS sieve) % by mass NIL NIL NIL NIL NIL NIL NIL NIL
9 Dispersibility (1% aq. suspension) % by mass 91.88 91.88 91.85 91.84 91.82 91.85 91.85 91.83
10. Rate of Dissolution and Solution Stability At OhAfter 18 h Opaque suspension with slight setting of particles (less than 1.0 mL) without any large particles3.0 mL of fine particulate sediments and 97.0 mL of suspension containing fine particles


Table -7 - The results of storage stability and corrosion characteristic for 30 months of Metsulfuron methyl + Sulfosulfuron (7+ 70%) Granules without POS (i. e. example A - 4) analysis are summarized below:
A-4
Sr No. Result/Storage period (months)
Parameters Oday 3 6 9 12 18 24 30
Corrosion Characteristics Perforation No
Darkening No
1 Leaking No
appearance of Shape Rectangular
container Color Silver
2 (Visual) Crack No
3 Appearance of the Test Substance Off- white free flowing granules
4 i A.I. Content (% w/w) a) Sulfosulfuron 70.80 70.507.21 70.18 69.98 69.42 69.19 68.75 68.50
b) Metsulfuron methyl 7.24 7.18 7.16 7.14 7.10 7.01 6.89
5 Wetting time (seconds) 9 9 9 9 10 10 10 10
Wet sieve test (retention on 6 200 BSS Test sieve) % by Imass 100 % passing through 200 BSS sieve
7 Dry sieve test analysis (% granules lying between 500-1000 um) 98.35 98.30 98.31 98.28 98.25 98.24 98.22 98.20
8 Dustiness (material passing theough 200 BSS sieve) (% by mass 0.10 0.10 0.10 0.10 0.10 0.10 0.11 0.11
9 Dispersibility (l%aq. suspension) % by mass 93.80 93.75 93.78 93.70 93.70 93.65 93.65 93.60
10. Rate of Dissolution and Solution Stability At Oh Opaque suspension with slight setting of particles (le 1.0 mL) without any large particles ssthan
After 18h 1.8 mL of fine particulate sediments and 98.2 ml suspension containing fine particles .of


Table -8 - The results of storage stability and corrosion characteristic for 30 months of Metsulfuron methyl + Sulfosulfuron (10 + 70 %) Granules with POS (i. e. example G-2) analysis are summarized below:G-2
Sr Result/Storage period (months)
No. Parameters Oday 3 6 9 12 18 I 24..... i...... _ 30
Corrosion Perforation No
1 Characteristics Darkening No
Leaking No
appearance of container (Visual) Shape Rectangular
Color Silver
2 Crack No
3 Appearance of the Test Substance Light creamish free flowing granule Creamish free flowing granule
. i A.I. Content (% w/w) i a) Sulfosulfuron 70.05 69.94 69.75 69.48 68.84 68.51 j 68.01 67.47
: b) Metsulfuron methyl 10.25 10.16 10.15 10.13 10.05 9.98 9.75 9.45
5 ' Wetting time (seconds) 16 16 16 16 | 16 16 17 18
6 Wet sieve test (retention on 200 BSS Test sieve) % By mass 100 % material passing through 200 BSS test sieve
7 Dry sieve test analysis (% granules lying between 500-1000 um) 98.50 98.52 98.54 98.55 98.45 98.45 98.40 98.34
8 9 Dustiness (material passing through 200 BSS sieve) % by mass 0.10 0.10 0.10 0.10 0.12 0.13 0.15 0.15
Dispersibility (l%aq. suspension) % by mass 92.08 92.87 92.55 92.60 92.65 92.85 92.86 93.00
10. Rate of Dissolution and Solution Stability At Oh Opaque suspension with slight setting of particles (less mL) without any large particles than 1.0
After 18h 3.0 mLc )f fine pai ■ticulate s contain ediments ing fine p and 97.0 articles mL of su spension

Table -9 - The results of storage stability and corrosion characteristic for 30 months of Metsulfuron methyl + Sulfosulfuron (10+ 70%) Granules without POS (i. e. example A-3) analysis are summarized below:
A-3
Sr Result/Storage period (months)
No. Paramfciei» Oday 3 6 9 12 18 24 30
Corrosion Characteristics Perforation No
Darkening No
1 Leaking No
appearance of container (Visual) Shape Rectangular
2 Color Silver
Crack No
3 Appearance of the Test Substance Off- white free flowing granules
4 A.I. Content (% w/w) a) Sulfosulfuron 70.20 70.14 70.01 69.85 i 69.64i 69.14 68.86 68.25
b) Metsulfuron methyl 10.27 10 10.26 10.23 10.20 10.18 10.12 10.01 9.84
5 Wetting time (seconds) 10 10 10 10 11 11 11
6 Wet sieve test (retention on 200 BSS Test sieve) % by mass 100 % passing through 200 BSS sieve
7 Dry sieve test analysis (% granules lying between 500-1000 urn) 97.80 97.82 97.79 97.74 97.70 97.35 97.25 97.05
8 Dustiness (material passing theough 200 BSS sieve) (% by mass 0.10 0.10 0.10 0.15 0.15 0.15 0.15 0.15
9 Dispersibility (1% aq. suspension) % by mass 93.50 93.55 i 93.58 93.59 93.60 93.60 93.61 93.56
10. Rate of Dissolution and Solution Stability At Oh Opaque suspension with slight setting of partu mL) without any large particle ;les (less than 1.0 s
After 18 h 2.0 mL of fine particulate sediments and 98.0 i containing fine particles mL of suspension


CONCLUSION:
Table-10 Comparison of active ingredient content during ambient storage stability study at 0 day and after 30 months of preparation for products with and without POS.

S.No Example No. (Sulfosulfuron+ Sulfosulfuron content after Metsulfuron methyl content after
Sulfosulfuron Metsulfuronmethyl Oday 30 months %degradation Oday 30 months %degradation
1 G-l-(with POS) 75 5 75.35 72.54 3.73 5.18 4.67 9.85
A-l- (without POS) 75.38 73.08 3.05 5.18 4.94 4.63
2 G-6- (with POS) 75 5 76.16 73.47 3.53 5.05 4.64 8.12
A-2- (without POS) 76.01 73.71 3.03 5.06 4.84 4.35
3 G-8- (with POS) 70 7 70.85 68.40 3.46 7.20 6.72 6.67
A-4- (without POS) 70.80 68.50 3.25 7.24 6.89 4.83
4 G-2- (with POS) 70 10 70.05 67.47 3.68 10.25 9.45 7.81
A-3- (without POS) 70.20 68.25 2.78 10.27 9.84 4.19
Note:
(Difference in active content value)
% degradation = X 100
(Active content value at o day analysis)


The comparison data of table 10, revealed that Metsulfuron methyl + Sulfosulfuron granules without polyoxyethylene sorbitan fatty acid ester was more stable than Metsulfuron methyl + Sulfosulfuron granules with polyoxyethylene sorbitan fatty acid ester under ambient condition of the storage even at the end of 30 months after preparation of samples..

We Claim:
1. A stable synergistic herbicidal composition, the composition comprising 5 to 10 % by weight of metsulfuron methyl, 70 to 80% by weight of sulfosulfuron, 1 to 25 % w/w of inert fillers, 0.1 to 10% w/w of a stabilizer, 0.1 to 1% w/w of a defoamcr, 0.1 to 5 % w/w of wetting and 0.10% w/w of dispersing and suspending agents.
2. The herbicidal composition as claimed in claim 1 comprising metsulfuron methyl in an amount of 5 to 7% w/w of the said composition.
3. The herbicidal composition as claimed in claim 1, wherein sulfosulfuron is present in an amount of 73 to 78% w/w of the said composition.
4. The herbicidal composition as claimed in claim 1, wherein metsulfuron methyl is present in an amount of about 5% w/w of the said composition.
5. The herbicidal composition as claimed in claim 1, wherein sulfosulfuron is present in an amount of about 75% w/w of the said composition.
6. The herbicidal composition as claimed in claim 1, wherein said inert filler is selected from a group consisting of ammonium sulphate and a mixture of 30- 40% w/w, with respect to the total inert filler, of attapulgite and 60-70% w/w, with respect to the total inert filler, of precipitated silica.
7. The herbicidal composition as claimed in claim 1, wherein the said stabilizer is hexamethylene tetramine.
8. The herbicidal composition as claimed in claim 1, wherein said defoamer is selected from tallow soap , silicon oil derivative or a mixture thereof.
9. The herbicidal composition as claimed in claim 1, wherein said defoamer is
Rhodorsil 426-R.
10. A process for preparing the herbicidal composition as claimed in anyone of
the above claims, said process comprising:
(a) preparing a first mixture by pre-blending 5 - 10 % metsulfuron methyl active content, 20 - 40 % of sulfosulfuron active content and 0.1 - 10 % of inert filler; milling said pre-blend and post-blending the milled mixture to get said first mixture;
(b) preparing a second mixture by pre-blending 30 - 60 % of sulfosulfuron active content, 0.1-10 % stabilizer, 0.01 - 15 % of inert filler, with 0.1 - 5 % wetting and 0.1 % dispersing and suspending agent; milling said pre-blend and post-blending the milled mixture to get said second mixture;
(c) preparing a spray solution being 10 - 40 % w/w of the composition by mixing 1-10 parts defoamer(s) and 50 - 500 parts water;
(d) charging completely said first mixture 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 said prepared 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 of 75 }i - 200 (i;
(g) charging completely said second mixture in the roto-granulator of step (f) and mixing said first and second mixtures by operating the roto-granulator for 3-5 minutes such that the pan is rotated 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 said prepared spray solution to the agglomerates of step (g), followed by mixing for another 10-15 minutes to get granules in size range of 100 - 1000 µ;
(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; and (k) conditioning the resulting granules obtained in step (j), by passing the granules through an air chamber to get chemically stable synergistic herbicidal composition.
11. The herbicidal composition as claimed in any one of the claims 1 to 9, the composition comprising metsulfuron methyl active content about 5% by weight of composition^ sulfosulfuron active content about 75% by weight of composition, 1 to 5 % w/w of inert fillers or a blend thereof, about 6.6% w/w of a dispersant and about 0.2 % w/w of a defoamer,
12. The herbicidal composition claimed in claim 11, wherein said dispersant is a blend of about 2.5% of sodium naphthalene sulphate, about 0.1% of lignosulfonate and about 4 .0 % of potassium polycarboxylate.
13. The herbicidal composition claimed in claim 11, wherein said filler is ammonium sulphate, precipitated silica or a mixture thereof.
14. The herbicidal composition claimed in claim 11, wherein said defoamer is a blend of about 0.1% of silicone defoamer and 0.1% of tallow soap defoamer.
15. The herbicidal composition claimed in claim 11, wherein said wetting agent is a blend of about 0.1% sodium dialkyl naphthalene sulfonate and about 4.2% of 3EO alkyl (C12-C13) ether sulfate.
16. The herbicidal composition claimed in claim 11, wherein said suspending agent is a blend of about 1.7% of ethylene oxide-propylene oxide and about 0.1% of a- alkyl (C10-C16) - co - hydroxypoly (oxyethylene) mixture.