FORM 2
THE PATENTS ACT 1970
(39 Of 1970)
And
THE PATENT RULES, 2003
(See Section 10, rule 13)
PROVISIONAL SPECIFI CAT ION
IMPROVED PROCESS FOR THE PREPARATION OF GRANULATED PRODUCTS
UNITED PHOSPHORUS LTD., A COMPANY REGISTERED UNDER INDIAN COMPANY'S ACT 1956 , HAVING ITS REGISTERED OFFICE AT 3 - 11, GDDC, VAPI - 396 195, STATE OF GUJARAT, INDIA AND HAVING ITS OFFICE AT UMPHOS HOUSE, 11th ROAD , C.D.MARG, KHAR (WEST) MUMBAY , 400052, MAHARASHTRA, INDIA, INDIAN.
The following specification describes the invention.
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Field of Invention:
The proposed invention relates to improved process for the preparation of granulated products . This invention particularly relates to an improved process for the preparation of granulated agricultural products such as Mancozeb, Propineb , Imidacloprid ,Surflan, Metribuzin , Metamitron, Alpha Cypermethrin, Cyhalothrin, Permethrin . The products prepared by the process of the proposed invention have low density , are loosely packed essentially dust free and of pre determined sizes, consistent quality in terms of size , hardness, dispersion and bulk density and devoid of binder. The products prepared by the process of the proposed invention are useful for consumers as such products due to their low bulk density , loosely packed , essentially dust free nature , are easy to use ,storage and transportation with low warehousing costs.
Background of the invention
Various processes are known in the prior art for the preparation of granulation products such as agrochemicals. Most commonly used processes for such granulation are Pan Granulation, Extrusion and , Spray drying, Each of these process has it's own drawbacks.
The Pan granulation process involves blending and milling of the ingredients irrespective of whether the ingredients have been previously milled, e.g. by air-milling or not. The resultant powder is then converted to a granule using a pan-granulator or similar device using water or water containing an adhesive. However, it seems to be the method most widely used.
The product obtained form a pan granulation process suffers from certain disadvantages which are highlighted below This is a rather crude process and control of granule size is difficult to achieve. There is non homogeneous distribution of water resulting into inconsistent quality of granules produced There is limited control on oversized granules formation leading to uncontrolled granulation. Generally addition of binder is necessary
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as the granules formed are susceptible to dust formation while bagging and transportation. Such a process can be used to produce narrowly sized granules of hardness and density with high production rates and therefore not economical In addition is a dusty operation effecting the environments . The process is lengthy.
The Pan granulated product generally result in inconsistent quality of granules. There is limited control on oversized granules formation leading to uncontrolled granulation. Generally addition of binder is necessary as the granules formed are susceptible to dust formation while bagging and transportation.
The product obtained by the extrusion process is not consistent in terms of the hardness, dispersion, bulk density of granules obtained varies. The extrudates obtained are of uneven length resulting in lack of uniformity in the final product. The products of extrusion are more Compact than products obtained by all other methods which directly affects dispersion and disintegration of granules. Extrusion aid components have to be included in the recipe
Extrusion process involves the tedious job of dough preparation and further drying of the wet dough produced .In a typical extrusion granulation process , the dry ingredients (or the dry ingredients and any liquid active agent or auxiliary agent which may be proposed) are mixed together in a premix stage. Water, up to about 40% by weight or more typically up to about 20% by weight is added with mixing to form an extrudable paste. In some instances the active ingredient or one of the auxiliary agents may be added in the form of an aqueous solution or dispersion or may have been produced for example as a damp solid. The process water is then reduced in proportion to the water which has already been incorporated. The extrudable paste (dough) is then fed to an extruder in which it is forced through dies to form cylindrical particles. After extrusion, the composition is usually dried, for example in a fluidised bed drier.
The product obtained by the extrusion process is not consistent. The hardness, dispersion, bulk density of granules obtained varies from batch to batch due to non-uniformity in
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dough. The strands obtained are of uneven length resulting in lack of uniformity in the final product. The products of extrusion are more compact than products obtained by all other methods which directly affects dispersion and disintegration of granules. Extrusion aid components have to be included in the recipe.
For the spray drying processes it is necessary to "blunge" the solids with a liquid (such as water) at as high a solids loading as possible consistent with adequate flow of the suspension, using high shear mechanical energy to effect deagglomeration and mixing the powder, the water, and any chemical additions necessary to control the rheological properties of the suspension.
It is known that the products produced by ordinary spray drying generally have a low mean particle size, typically within the range 50-150 u m , in some cases even less and often proposed serious dust problems. A large percentage of fine, starting particles is characteristic for the known granulation processes involving spray drying. This high percentage actually represents a problem in the straight-through process because it leads to the formation of a granulated product with an unacceptably high content of dust.
Spray drying method requires Capital investment for wet grinding/spray drying technology. The Cost of overheads is more. The spray drying process becomes lengthy due to nozzle chocking and the process is not suitable for low melting actives The product obtained from spray drying are prone to dust generation while bagging and transportation. The Active materials are exposed to higher temperatures.
In the proposed day context, particularly in the agricultural area there is a high demand for products having low density, loosely packed essentially dust free and of pre determined sizes, consistent quality in terms of size, hardness, dispersion and bulk density and devoid of binder. The demand is due their low bulk density, loosely packed, essentially dust free nature, are easy to use, storage and transportation with low warehousing costs.
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The major difficulty, though, is to find a relatively inexpensive and efficient process to produce such a product.
Thus there is need for a granulated product which is of consistent quality of granules in terms of size, length, hardness, dispersion, bulk density and which is devoid of aid components and which is not prone to dust generation while bagging and transportation.
Objectives of the invention:
Therefore the main objective of the proposed invention is to provide a process for the preparation of granulated products devoid of the draw backs of the hitherto known processes in the prior art.
Another objective of the proposed invention is to provide an improved process for the preparation of granulated products which are non dusty water dispersible granular preparation and the granules produced have consistent quality in terms of size, dispersion, bulk density and devoid of aid components.
Yet another objective of the proposed invention is to provide an improved process for the preparation of granulated products which is a relatively inexpensive and environmentally safe.
Still another objective of the proposed invention is to provide an improved process for the preparation of granulated products which is a relatively inexpensive (low processing overheads cost) and environmentally safe (dust free).
Yet another objective of the proposed invention is to provide an improved process for the preparation of granulated products without any limitations to the melting points of the products which are to be granulated.
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Still another objective ofthe proposed invention is to provide an improved process for the preparation of granulated products which are not prone to dust generation while filling in bags and transportation thereby avoiding polluting the environment.
Yet another objective of the proposed invention is to provide an improved process for the preparation of granulated products without exposing the products which are to be granulated to higher temperatures during granulation, thereby making the process not only economical but also simple.
Yet another objective ofthe proposed t invention is to provide an improved process for the preparation of granulated products without using any aid components such as binders etc thereby making the process relatively inexpensive and efficient.
The above mentioned objectives of the proposed invention have been achieved by our sustained R&D due to our finding that if uniform wetting ofthe powder ofthe product which is to be granulated and the granulating liquid are achieved . We observed that such uniform mixing is possible if the granulating liquid is passed in two phases, counter currently, through the powder of the product to be granulated taken in a rotating tank, the tank being kept in 45 Degree angle.
Summary of the proposed Invention
Accordingly, the proposed invention provides an improved process for the preparation of non dusty granulated products having consistent quality in terms of size , hardness, dispersion and bulk density, which comprises
(i) mixing a powder ofthe product which is to be granulated , with powders of a
wetting agent, a dispersing agent and an inert filler; (ii) adding a portion ofthe required quantity of a granulating liquid to a rotating mixing tank containing the powder prepared described in step (i) through an inlet, which also serves as a stirrer , the rotation of the tank being in the clockwise or anticlockwise direction , the rotation being at a speed in the
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range of 10 to 60 RPM, the tank being kept at an angle in the range of 20 to 60 Deg with respect to its horizontal position; (iii) adding the remaining quantity of the granulating liquid through the same inlet which rotates in an opposite direction with respect to the rotation of the tank , the rotation of the inlet being at a speed in the range of 500 to 2000 rpm , the rotation of the tank being in the range 10 to 60 RPM . so as to have an counter current effect in mixing the powder and the granulating liquid to obtain the granulated products;
(iv) sieving the granulated products to obtain the desired sizes of the products; and
(v) drying the sieved granulated products.
The above process is conducted in an apparatus which is shown in Fig 1 of the drawing accompanying this specification.
The apparatus as shown in Fig 1 comprises a rotating mixing tank (A) having cylindrical walls. The Tank (A) is inclined at an angle 0 which may vary from 20 - 60 degrees with respect to the horizontal. The mixing tank has a stand (B) which comprises a base frame (C) secured to a foundation (D) . The apparatus also has an inlet (E) to add granulating liquid in the rotating mixing tank (A). The Inlet (E) also serves as a stirrer with the ability to rotate at a speed of 500 - 2000 rpm.
By the term wetting agent is meant a compound which permits the granule to rapidly penetrate into the water, and, more precisely, a compound which, when mixed in selected proportions with agriculturally active compounds, in the form of granules, give a mixture which has a wettability time of less than 2 minutes. This wetting agent can be an ionic or non-ionic agent or a mixture of such surface-active agents.
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Compounds which are usable as wetting agents and which can be cited are, for example, the alkylarylsulphonate-type salts, in particular the alkali metal alkyinaphthalene sulphonates, the salts of polycarboxylic acids, polycondensates of ethylene oxide with fatty alcohols or with fatty acids or with fatty amines, or substituted phenols (in particular alkylphenols or arylphenols), and salts of esters of sulphosuccinic acids.
By the term dispersing agent is meant a compound which ensures that the particles remain suspended in the application mixture and which allows rapid disintegration of the granule in the water. More precisely, by dispersing agent is meant a compound which, when intimately mixed in selected proportions with agriculturally active compounds , in the form of granules, gives a mixture which has a suspensibility of more than 50%. The dispersing agent can be an ionic or non-ionic agent or a mixture of such surface-active agents.
As compounds which are suitable as dispersing agents there may be cited, for example, arylsulphonate-type polymers, in particular the alkali metal polynaphthalenesulphonates obtained by condensation of (alkyl)arylsulphonates with formaldehyde, the lingo sulphonates, the polyphenylsulphonates, salts of polyacrylic acids, salts of lignosulphonic acids, salts of phenolsulphonic acids or naphthalenesulphonic acids, taurine derivatives (in particular alkyltaurates), phosphoric esters of alcohols or of polycondensates of ethylene oxide and phenols, esters of fatty acids and polyols, and the derivatives of the preceding compounds which have sulphate, sulphonate and phosphate functions.
The term" inert filer" refers to a solid organic or inorganic material, natural or synthetic, with which the active substance is combined so as to facilitate the specific application of the granulated product This filler is therefore generally inert and acceptable The filler can be selected for example from amongst clay, diatomaceous earth, the natural or synthetic silicates, silica, soluble or insoluble mineral salts, organic derivatives, and polysaccharide compounds such as starch, cellulose, sugars and lactose.
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Preferred granulating liquid may be water , organic or inorganic solvents or a combination therof or a solution containing dissolved wetting and dispersing agents.
Preferred fillers which can be used are hydrophilic fillers which have a disintegrating action, that is to say which facilitate the rupture of the granule according to the invention in the presence of water. As compounds of this type there may be mentioned the bentonites (natural or activated), starch and its derivatives (in particular the alkylstarches and the carboxyalkylstarches), the celluloses (in particular microcrystalline cellulose) and the derivatives of cellulose (in particular carboxyalkylcellulose), the alginates, soluble mineral salts, or reticulated polyvinylpyrrolidone.
Besides the product used for granulation the product ( first compound) nmay contain at least a second active compound of a type which differs from the first compound, which has the aim of widening the spectrum of the first one.
In the case of agro chemicals used for granulation, the first and second compounds may be a contact pesticide, which act by contact with the plants/pests. As compounds of this type, there may be mentioned Mancozeb, Propineb , Imidacloprid ,Surflan, Metribuzin , Metamitron, alpha Cypermethrin, Cyhalothrin, Permethrin.
This second compound may be present in the granulated product prepared by the process of the proposed invention in an amount between 0.01 to 50.0 %, preferably between 0.1 to 40.0 % (percentages based on the total granulated product). The first agricultural compound may be present in quantities , preferably between 9.9 to 55.0 %., the other ingredients in the end product being the wetting agent, dispersing agent and inert filers Besides the above-described ingredients the granulated product may also contain 50.1 to 90.0 % of suitable additives, such as antifoams, sequestering agents, stabilisers, penetrating agents, adhesives, anti-caking agents, colorants, and others.
The process of the proposed invention is generally carried out starting with the preparation of the powders of the product to be granulated, the wetting agent , the
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dispersing agent and the inert filler The pesticides which may used with the active substance may be absorbed or adsorbed on a solid support such as, for example, silica, diatomaceous earth, kaolin clay or a combination thereof. The mixing of the powders may be done in suitable mixers.
According to the proposed invention the powder taken in the mixing tank of the apparatus is mixed with granulating liquid ,from 1 to 30%, preferably 10 to 15 % of the required quantities .This moistened powder has the consistency of a non drifting dust. This is further processed in the tank with the addition of remaining quantity of the granulating liquid in such a way as to obtain the granulated product.
The process may use a mixture of the powders prepared by mixing 10 to 95% by mass of at least one active substance in solid or solidified form, 1 to 10% by weight of a wetting agent, 1 to 10 % by weight of a dispersing agent and 70 to 88% by weight of an inert filler.
The granulated agricultural products which are prepared according to the process of the proposed invention, which are diluted by the agriculturalists in containers which contain water for application These diluted mixtures are usually applied at 50 to 10001/ha.
The process is described with reference to the granulation of Mancozeb powder though the same process can be applied to any products which are to be granulated.
The powder of Mancozeb is mixed with the desired wetting , dipersing agents and the filler in desired quantities . The resultant mixture is taken in the chamber of the apparatus shown in fig 1. The chamber is rotated in clockwise direction at a speed in the range of 10 - 60 RPM and the chamber being inclined at an angle between 20 - 60 Degree. A portion (say 25%) of the granulating liquid such as water of the total quantity required, is then passed through the inlet (E ). In this embodiment the inlet is stationary, though it can be rotated in an opposite direction ( namely in this case anticlockwise) and also serve as a stirrer. Thereafter the remaining portion of the granulating liquid is passed
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through the inlet which is now made rotating in anticlockwise direction with reference to he direction of rotration of the chamber so as to have a counter current mixing of the powder and the granulating liquid . The rotation of the inlet may be in the range of and the rotation of the chamber being the same as mentioned earlier.
After the above mixing is over , the granulated product obtained is seived to get he desired sizes of the granulated products and dried . The sieving and drying , if desired , may be repeated to get the exact sizes of the granulated products.
The comparative differences in the products obtained by conventional methods of spray drying , extrusion and Pan granulation process as compared to the product granulated according to the process of the proposed invention are as below,

s.No Characteristics Spray Dried product Product ofProposedInvention Extruded product Pangranulatedproduct
1 Dustiness Dusty Non -dusty Dusty Dusty
2. Size of Granules Not uniform Uniform Not uniform Not Uniform
3 Density Low Medium High medium
4 Packing Hollow Loosely Packed Tightly packed Loose packing
5 Dispersability High Low lowest highest
6 Compactness Least compact Less compact More compact Less compact
7 Size < 100 um < 100 um >100um >100um
Thus the granulated product of the proposed invention is a solution to all the problems associated with all the earlier known granulated products. The granulated product of the proposed invention has characteristics which have been required but not been achieved by any earlier known processes of granulation.
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The comparative differences in the conventional processes of spray drying , extrusion and pan granulation as compared to the process employed to obtain the granulated product according to the process of the proposed invention are shown below,

s.No Characteristics Spray drying Process ofProposedInvention Extrusion process PanGranulationProcess
1 Recycling of non uniform granules Recyling done Single pass. Norecyclingrequired. Recyling done Recycling done
2 Operation Dusty Non dusty Dusty Dusty
3 Water used More Less Least Less
4 Wear and tear of machinery Least Less More Less
5 Drying energy Most Least Less Less
6 Mechanical energy Least Less Most Less
7 Multi material mix Not possible Possible Possible Possible
8 Size decided by Viscocity of liquid High attrition between the agglomerates The size of the orifice. Speed of Pan, spray size
The characteristic outcome of the employment of the process of the proposed invention is the wetting of almost 100% of the particles with a minimum of water without keeping the particles in a flowable slurry form.
The granulated product prepared by the process of the proposed invention have the following characteristics
• a wettability time of less than 4 minutes, preferably less than 2 minutes;
• a dispersibility of more than 75 %, preferably more than 90.0 %;
• a suspensibility of more than 25 %, preferably more than 50%.
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The process has the following advantages.
1. It is a non dusty operation.
2. The amount of the granulating liquid used in the process is very less.
3. There is homogenous distribution of the granulating liquid into the solid non -dusty phase.
4. The process affords complete control on the size of the granules produced.
5. The processing time is short as compared to the known processes.
6. The drying time is short as compared to conventional spray drying process.
7. The drying temperature is also less leading to energy savings as compared to conventional processes.
8. The counter current process leads to a three dimensional mixing.
9. The process affords multi material mixing leading to better granulated product of combined active ingredients.
10. The process enables full and complete process control of granulation by layering to produce products in a narrow size range in a single pass. Single pass means the primary yield with substantially little/no recycle employed.
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The product of the proposed invention has the following advantages
1. Uniform size of the Granules produced.
2. The granules produced are binder & dust free.
3. The granules produced have uniform hardness, dispersion & bulk density.
4. The granules do not require specialized driers.
5. The granules have moderate density leading to loosely packed product.
6. The granules have better dispersibility and disintegration characteristics.

Dated this 8th day of May 2006

M B Trivedi Company Secretary
United Phosphorus Limited
Uniphos House, 11th Road,
C. D Marg, Khar (W), Mumbai.
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