FORM-2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE
Specification
(See section 10 and rule 13)
A PROCESS FOR THE PREPARATION OF MANCOZEB WATER DISPERSIBLE GRANULAR FORMULATION AND THE FORMULATION
MADE THEREOF
INDOFIL CHEMICALS CO.
( a division of MODIPON LTD.)
An Indian Company
of Nirlon House, Dr. Annie Besant Road, Mumbai 400 025, Maharashtra, India

THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED.


This invention relates to a mancozeb formulation.
In particular, the invention relates to a process for making a water dispersible granular formulation of the water insoluble fungicide based metal salts of ethylene bisdithiocarbamic acid commonly referred to as mancozeb.
BACK GROUND AND PRIOR ART
Wettable powders are generally produced by first blending the technical grade chemical (which may already be in a finely divided state, e.g in an air-milled form), with surfactants (wetting and dispersing agents), fillers and possibly other ingredients . The mixture is then passed through an air mill or other suitable milling device to reduce the size of the additives (and technical chemical if not previously milled) as well as produce an intimate mixture of the components.
The resultant wettable powder is generally very bulky and becomes air borne readily. This can be hazardous to the user in the case of irritant or toxic materials.
Pesticide active ingredients -according to the characteristics of the actives and of their intended applications - can be formulated as dusts, wettable powders, Dispersible granules, suspension concentrates, emulsifiable concentrates, emulsions and concentrated solutions, and their application as formulated products on soil, seeds, or plant foliage is generally carried out with aqueous spray in the form of suspension or emulsion.
The wettable powder is dusty and has a tendency to get suspended in the air during handling of open storage containers. Also, another threat posed by these wettable powders is the possible damage to environment, soil, water, plant and animal life, in the neighboring areas where these powders are being charged to application equipment for use. Wettable powder in particular, is a serious threat to the user, as it is known to cause a combination of nausea and vomiting, if inhaled as a dust. Suspension concentrates pose a problem during transportation, as they are not economical to transport being in an aqueous form, leakages
2

and packaging, as disposal of the containers is an environmental hazard. EmulsifiabJe concentrates are undesirable due to the use of the toxic solvents.
In order to over come some of the problems resulting from the use of conventional pesticidal formulations, researchers and organizations have conducted a through search and investigation in the field of formulation technology, which has evolved into a relatively new concept of water dispersible granules (also known as dry flowables). These are granular formulations of agricultural chemicals that when properly formulated, disperse readily in water and remain in suspension. Water dispersible granules have different characteristics based on the type of process used for manufacture, and on the formulation agents used. Various parameters such as Suspensibility, spontaneity of dispersion, wetting out period, etc determine the quality of water dispersible granule formulation.
The kind of process, the process parameters, formulation agents, play a vital role in the quality and characteristics of the water dispersible granule formulation. Water dispersible granules containing agricultural chemicals which are designed to disperse readily in water and remain in suspension i.e perform as well as liquid flowables and wettable powders when prepared for spray application to soil or plants. Within the meaning of the present invention, a dispersible granule does not denote a granule which, applied as such, while dry, to the soil, can however disintegrate at the end of a certain time in the environment,.
SUMMARY OF PRIOR ART PROCESSES
Patent US 5628800 describes a process for preparation of water dispersible granules from an aqueous dispersion or solution of solids which comprises of spraying of the aqueous dispersion or solution by counter-current principle into a stream of fluidizing chamber and causing it to fluidize starting the formation of granules in a start up phase at 10-60% of the maximum gas flow and time cycle for the process being maintained. Initial feed rates are only up to 30%, which subsequently is increased. Claims in the process are for the gas flow, which are nitrogen or air and maximum feed rate of dispersion . Claims have been made for the temperatures of operations, which vary between 90 to 180 degree centigrade. A group of pesticides as mentioned in the specifications have been claimed, though not very clearly
3

specified, as the actives for the preparation of the water dispersible granules (WG). The dispersion or solution containing one or more adhesives, tackifiers, dispersing and wetting agents and stabilizers has been claimed for the actives. The process also claims auxiliaries for the formulation of pesticides. A system by which dusts are carried over to the filter to the drying chamber is claimed.
US 5001,150 describes a process for the preparation of Mancozeb essentially consisting of an aqueous slurry of about 40-45% by weight of solids with specified percentages of binding agent, dispersant, paraformaldehyde, zinc sulfate, dispersing agent and maneb. The process consists of wet milling to obtain slurry of specified particle size and further adding slurry having essentially the same composition of specified %, spray drying the slurry obtained in second step and recovering non-dusty mancozeb granules of specified particle size with low ethylene thiourea content.
Spray drying is done at inlet temperature of 290 degree to 320 degree and an out let temperature of 122 degree-123 degree.
These two prior art processes use high temperature for making granules.
US 5443764 describe a process for making water dispersible granules by extrusion method.
Percentages of actives and compositions have been provided.
US 6004570 describes a dithiocarbamate fungicide composition which comprises 1 to 95% of one or more dithiocarbamate fungicides and poly vinyl alcohol of definite molecular weight and particle size. Claims are made for the application and the type of formulation in which poly vinyl alcohol can be incorporated in wettable powder, dispersible granules and flowables consisting of dithiocarbamates as active ingredients.
US 6387960 suggests use of monoglyceride use in various formulations in formulations including dry flowables along with the mancozeb, classes of non-ionic surfactants, anionic and cationic surfactants, allyl esters, phytobland mineral oils, water soluble silicone surfactants, dialkyl ethers, fatty dialkyl carbonates, vegetable oils and mixtures thereof are claimed for.
4

US 6255254 describe solid compositions characteristics with one or two actives and complicated containerization system.
US 6273929 describes a composition of dispersible granules using extrusion technology and a organosilicone . Use of other ingredients such as wetting agent, dispersant, filler component and binding component are described.
US 6375969 relates to certain diatomaceous earth compositions, which can be dry spread on the soil to deliver a pesticide or a carrier. Methods of delivery of a bioactive component to a site to be treated include broadcasting upon the site a bioactively effective amount of a dry spreadable granular composition of specified diatomaceous earth, surfactant compositions, polymeric anionic surfactant disintegration aid, and a non-polymeric anionic surfactant rewetting agent and binder system.
US 5389674 describes an improved fungicidal dithiocarbamate particulate compositions
claiming use of specific percentage one or more components selected from dithiocarbamate
and bisdithiocarbamoyl disulfides and an effective amount of moisture to significantly
enchance the flowability of the compositon. A process of producing the above
compositions using an initial wet-milling and further spray draying the slurry with the exhaust temperature of a min of 115 deg centigrade has been described.
US 6617301 describes surfactants mixtures with improved wetting or emulsifying properties for use in agrochemical preparations comprising an alkyl polyglucoside or an anionic derivative of alkyl polyglucoside with an anionic derivative of fatty alcohol. The fore mentioned combination is claimed to find its use in various pesticidal compositions including dispersible granules of mancozeb.
US 6436421 describes pesticide compositions comprising a pesticide and a redispersible polymer and a method of controlling the agricultural pests by applying to the pest the claimed formulation. The specific agricultural chemicals, polymer constitution and type of pesticide formulation are described.
5

US 6677399 describes water dispersible solid granular agrochemical formulations, typically in the form of wettable powders, particularly having an average particle size from 5 to 50 Microns or water dispersible granules, particularly having an average particle size of from 200 mum to 5 mm, including one or more water dispersible agrochemical active components and a dispersing agent including a water dispersible styrene (meth) acrylic copolymer. Along with constituents of the formulation spray mixes made by various methods are also described. The copolymeric dispersing agent, may include monomer residues which include strongly acidic, particularly Sulphonic acid groups.
IN 188928 describes a process of manufacture and the composition of the formulation. The hot air temperatures range from 100 to 320 degree centigrade. Atomized particles are then simultaneously agglomerated to form the water dispersible granules. This process also uses high temperature.
The invention herein envisages a water dispersible granular formulations and to a process for the preparation thereof. The water dispersible granular formulations of the invention are prepared by mixing appropriate quantities of aqueous dispersion of the slurry with suitable adjuvant using a unique process of spray -drying at relatively lower temperatures, resulting in consumption of much less energy and therefore making the process efficient and inexpensive.
Summary of the invention
Certain metal salts of ethylene bis dithiocarbamic acid , particularly zinc , manganese , copper , iron salts alone or in combination of two metal salts are known to catch fire at higher temperatures . High temperature operations therefore become a very risky proposition to handle heat sensitive products as above. The temperature utilized by all spray drying operations are in the range of 120 degree centigrade and above, some times going to temperature as high as 200 to 300 degree centigrade. The precautions to be taken in case of eventual safety issues are immense.
More over the product faces stability issues on being spray dried at higher temperatures.
6

The aim of the invention is to provide a process, which is safe to use.
This novel process employs temperature between 40 to 90 degree Celsius to produce water dispersible granules of a superior type. Not only does the product have superior attrition properties and lower dust content, the suspension characteristics achieved by employing this process are very good. The stability of the product is also higher than the product produced by the conventional processes employed as in prior art.
Accordingly, a particularly preferred embodiment of the invention provides a process for forming a water dispersible granule comprising grinding of the active and post blending of slurry with various additives to and spraying of the slurry and drying of the granules in the same equipment.
In addition to the active ingredient component the ingredients will normally include a surfactant component and optionally other components such as filler component to provide the desired active ingredient content and / or a binding agent.
The term surfactant is used in the broad sense to include materials, which may be referred to as emulsifying agents, dispersing agents and wetting agents and the surfactant component may comprise one or more surfactant selected from the anionic, nonionic type.
Examples of surfactants of the anionic type include sodium dodecyl benzene sulphoante, sodium, calcium or ammonium lignosulphoante, sodium formaldehyde condensates polymer salt (Lomar D [tm]), Naphthalene formaldehyde condensate sodium salt (Morwet D 425 [tm])
Suitable non ionic type surfactants include for example condensation products of ethylene oxide with alkyl phenols such as octyl phenol, nonyl phenol.
Preferably the surfactant component will comprise at least one wetting agent such as those selected from alkyl naphthalene sulfonates, phosphate esters, and / or at least one dispersing agent such as those selected from the group of naphthalene condensates, Hgno sulfonates .
7

Typically the total surfactant component will comprise from 2 to 20% and preferably from 3 to 15% by mass of the dry weight of the composition .
The dispersions or solutions preferably contain adhesives, such as for example starch syrup, dextrose, sucrose, dextrin, poly vinyl acetate. In addition the granules can contain inert material such kaolin or agents which promote the bursting of the granule-grains in water such as penta sodium triphosphate
This invention results in Mancozeb water dispersible granules having diameter size in the range of 150 to 850 micron Containing by mass.
1. 2 to 4% binding agent
2. 2 to 14% dispersing agent / wetting agent
3. 0.2 to 2% para formaldehyde
4. 2 to 7% zinc sulphate

5. 3 to 5 % hexamethylene terra mine
6. 73.5 to 88% of Maneb
7. 0.2 to 1% sodium tripolyphosphate
8. 0.1 to 0.3% non silicone oil [defoaming agent]
Preferred composition of the invention consists of or consists essentially of
a. 2 % of binding agent.
b. 10% of sodium ligno sulphonate [dispersing agent/wetting agent] 1% of
sodium naphthalene sulphonate formaldehyde condensate [additional
dispersing agent]
c. 0.36% para formaldehyde
d. 5.8% of zinc sulphate
e. 2.2% of Hexamethylene tetra mine
f. 78% of Maneb
g. 0.2% Defoamer
h. 0.4% of disintegrating agent
8

Process description
Mancozeb 75% WG (Water dispersible granules Is formulated using Fluisized Bed
equipment)
Five stages are involved:
a. pre-Mixing (Homogenization)
b. Wet-Milling (for particle size Reduction)
c. Post Blending
d. Spraying /drying
e. Sieving
Pre-Mixing
a. Required quantity of adjuvant is charged to Maneb slurry in tank 2.
Wet-milling
b. Blended slurry is directed from tank 2 to wet mill via pump where it is milled to
reduce the particle Size (Range 2 to 4 micron) .
Post Blending
c. Grinded slurry is transferred to Blend tank 3 where the required quantity of
Binder along with additional quantity of dispersing agents / adjuvant are added to
obtain Mancozeb slurry having Total solids in the range of 48 to 56%.
Spray drying
d. Slurry from the blend tank 3 is sprayed at inlet temperature ranging from 40 to 90
degrees and granules formed. It is dried at temp range of 60 to 80 degree.
Sieving and Packing
e. The dried granules are passed through a sieve to recover a final product i.e.
mancozeb water dispersible granules having particle size in the range of 150 to 850
)
microns which is analyzed as per CIPAC method.
9

Example one:
An aqueous Maneb slurry prepared by addition of Manganese sulphate to aqueous solution of sodium ethylene bisthiocarbamate is filtered to remove excess water and water soluble salts. The resulting Maneb cake is mixed with various adjuvant and water in a repulp tank to form aqueous solids concentration. The composition in the repulp tank is (dry basis is as follows):

Percent on dry basis
Zinc sulphate 5.16
Sodium ligno sulphonate 3.04
LomarD 0.92
Hexamethylene tetramine 2.62
NopcoNXZ 0.26
Maneb 88
100
The slurry is pumped to wet mill and milled to a particle size of 2 to 4 micron. The slurry is then pumped to a mix blend tank where further adjuvant is added so that the final composition having total solids in the range of 48 to 56% is obtained. This slurry is then sprayed dried in FBE-5 equipment, while maintaining the inlet air temperature at 60 degree and product temperature range (35 degree to 42 degree), the outlet temperature at 40 degree during spraying, And inlet temperature at 90 degree and outlet temp at 70 degree during drying. The material is sieved through sieve shaker consisting of sieves (850 micron and 150 micron). The moisture content of the product under such conditions is less than 2.5%.
10
16 SEP 2008

Final composition on dry basis

Percent on dry basis
Zinc sulphate 5.8
Sodium lignosulphonate 10
Sodium naphthalene
Sulphonate condensate (LOMAR D) 1
Hexamethylene tetramine 2.2
Nopco NXZ 0.2
Maneb 78
Sodium tripolyphosphate 0.4
Dextrose 2
poly vinyl alcohol 0.04
Para formaldehyde 0.36
100
Example no 2:
Same recipe is used expect that the spray drying conditions are changed. This slurry is then sprayed dried in FBE-5 equipment, while maintaining the inlet air temperature at 70 degree and product temperature range (36 degree to 41 degree), the outlet temperature at 40 degree during spraying, And inlet temperature at 70 degree and outlet temp at 45 degree during drying. The moisture content of the product under such conditions is less than 2.5%. Example no 3:
Same recipe is used expect that the spray drying conditions are changed. This slurry is then sprayed dried in FBE-5 equipment, while maintaining the inlet air temperature at 80 degree and the Product temperature range (35 to 43 degree), outlet temperature at 50 degree during spraying, And inlet temperature at 80 degree and outlet temp at 50 degree during drying. The moisture content of the product under such conditions is less than 2.5%.
11
16 SEP 2008

Example no 4:
Same recipe is used expect that the spray drying conditions are changed. This slurry is sprayed dried in FBE-5 equipment, while maintaining the inlet air temperature at 90 degree and the outlet temperature at 40 degree during spraying, And inlet temperature at 90 degree and outlet temp at 50 degree during drying. The moisture content of the product under such conditions is less than 2.5%.
The following parameters relating to Mancozeb granules were determined before and after aging at 54 ± 2°c for 14 days.

PARAMETERS Example 1
Before Aging Example 1
After Aging Example 2
Before Aging Example 2
After Aging Example 3
Before Aging Example 3
After Aging Example 4
Before Aging Example 4
After Aging
Active content (% w/w) 75.5% 75.1% 77.1 76.4 76.1 75.8 75.18 74.8%
Suspensibility
%w/w 66% 64% 82 78% 78.7 77% 82.6 80.1%
Wetting out time 3 sec 3 sec 4 sec 4 sec 5 sec 4 sec 4 sec 4 sec
Dust content 8mg 9mg 8mg 7mg 9mg 8mg 9mg 9mg
Attrition resistance 92% 91% 93% 92% 92% 91% 90% 90%
PH (1% solution) 6.9 7.0 7.1 7.0 7.1 6.9 7.1 7.0
Moisture content (%w/w 2.1 1.9 1.8% 1.9
12

The following CIPAC methods were used for the analysis of various parameters

SI No. Parameter Method of Analysis
1 Active substance content CIPAC method 34/3/M/6.3
2 PH of 1% w/v aqueous dispersions CIPAC method MT75.1
3 Wettability (without swirling) CIPAC method MT 53.3.1
4 Dustiness CIPAC method MT 171.1
5 Attrition resistance (Friability and attrition characteristics) CIPAC method MT178
6 Water (moisture) content CIPAC MT 30.2
7 Suspensibility (Suspension stability) CIPAC method MT 168
Determination of Dust Content
The method of determination is based on CIPAC method MT
171.1. Outline of Method
A known amount of the test item was allowed to fall under standard condition in a test chamber, releasing the dust. The released dust was collected and quantified by gravimetric method.
Determination of Dust: The empty weight of filter paper disc (Wl), in gram, was recorded and put on the filter plate. Then the air flow meter was connected with dust measuring apparatus and vacuum pump through tubing and plugged the filter into the fitting of the measuring box. The vacuum pump was started and airflow was adjusted to
13

15 L/min. Then the weighed quantity (30 g) of the test item was dropped in a single action into the pouring tube, and stopwatch was started simultaneously. Thus the liberated air borne dust was sucked of for 60 seconds and collected on the filter paper disc. The filter paper disc along with the dust collected on it was taken off from measuring box and weighed (W2) in grams. Calculation
Dust content, mg = (W2 - Wl) x 1000 Based on the weight of the dust (mg) obtained the test item was categorized by using the following table.

Dust collected (mg) Category
0-12 Nearly dust free
12-30 Essentially non dusty
>30 Dusty
Determination of Attrition Resistance
The method of determination is based on the CIPAC method MT 178. Out line of Method
• The test item was first sieved on a 125um sieve in order to remove fine
particles. A known quantity of dust-free granule (test item) was transferred to a glass bottle and was then subjected to a rolling movement with an equal quantity of glass beads. After rolling for a specified period, the attrition resistance was determined by sieving again on a 125um sieve,
Procedure
About 60g of homogeneous test item was weighed and sieved through a 125um sieve fitted on a shaker for 3 minutes to remove the fine particles.
Accurately weighed quantity of about 50.0 g (W) of the sieved granules and equal weight of glass beads were transferred to a glass bottle. The bottle was closed, placed horizontally onto the roller, and rotated for about 4500 revolutions (counted by revolution counter) with a rotation speed of 100 r.p.m.
14

The nest of 125 urn sieve with coarse sieve with the former underneath and mounted it on the receiver pan. The contents of the glass oottles were transferred carefully on the coarse sieve. The glass beads were brushed to ensure that the material adhering to them fell onto the 125 urn sieve. The material remaining inside the lid of the bottle or adhering to the surface of the bottle was removed using the brush or glass rod and added to the other material on the 125 um sieve. The lid of the sieve to the nest of sieves was fitted and mounted it on the shaker.
The nest of the sieves was shaken for a period of 3 minutes, and the sieves were removed from the shaker. The lid was taken out, and the material on the 125 um sieve was transferred to a tared crystallizing dish. The side of the sieve frame was tapped five times and the lower surface was brushed without inverting the sieve. These fractions were discarded. Then the upper surface was brushed, inverted and added to the material on the dish. The mass of the material transferred to the dish was weighed (a). Calculation
Attrition resistance, % a x 100
m/m W
Determination of Water (Moisture) Content
The determination was done as per Method CIPAC MT 30.2. Out line of Method The moisture (water) in the test item was determined by forming an azeotropic binary
mixture with toluene and then distilling Determination of Suspensibility
Suspensibility of the samples was determined with CIPAC standard water D as per the procedure of CIPAC method MT 168. Out line of Method
A suspension of known concentration of the test item was prepared in CIPAC Standard Water D, placed in a measuring cylinder at a constant temperature and allowed to remain undisturbed for the specified time. The top 9/10ths were drawn off and the content of solids in the sediments in the bottom 1/10th was determined.
15

When combination of stabilizer HMT and para formaldehyde is used the drop in active content is only 0.4%.
Example five:
In this experiment the concentration, temperature variation and variation of surfactants is
carried out. Stabilizer used is Paraformaledhye. The slurry is pumped to wet mill and milled
to a particle size of 2 to 4 micron. The slurry is then pumped to a mix blend tank where
further adjuvant are added so that the final composition having total solids in the range of
48 to 56% is obtained. This slurry is then sprayed dried in FBE-5 equipment, while
maintaining the inlet air temperature at 50 degree and the outlet temperature of 40 degree
during spraying, And inlet temperature at 90 degree and outlet temp at 70 degree during
drying. The material is sieved through sieve shaker consisting of sieves (850 micron and
150 micron).
The moisture content of the product under such conditions is less than 2.5%.
Percent on dry
basis
ABC

Maneb 76.82 76.96 77.1
Para formaldehyde 0.94 0.94 0.94
Zinc sulphate 5.92 5.92 5.85
NopcoNXZ 0.16 0.16 0.16
Dispersing agent B 6.24 8.52 4
Dispersing agent A 6.17 3.91 10.2
Dextrose 2.19 2.19 1.15
STPP 0.78 0.7 0.30
Nonyl phenol ethoxylate 0.78 0.7 0.30
100 100.00 100
16
6 SEP 2008

Dispersing agent A: sodium ligno sulphonate
Dispersing agent B: sodium naphthalene formaldehyde condensate
The following parameters relating to Mancozeb granules were determined before and after aging at 54 ± 2°c for 14 days.

PARAMETERS Example A
Before Aging Example A
After Aging Example B
Before Aging Example B
After Aging Example C
Before Aging Example C
After Aging
Active content (% w/w) 77.05 75.45 77.07 16 78.19 75.90
Suspensibility %w/w 81.81 78.26 81.13 72.64 91.52 74.65
Wetting out time 3 sec 3 sec 3 sec 3 sec 3 sec 3 sec
Dust content 9.8 mg 10 mg 10.9 mg 11 mg 2.5 mg 5mg
Attrition resistance 99 95 92 91 98 97
PH(1% solution) 6.9 6.9 6.9 7.1 7.11 7.2
Moisture content (%w/w 1.6 1.2 1.4 1.5 1.2 1.6
Ethylene thiourea 0.045% 0.09 0.047 0.07 0.057 0.014

The data shows that the increase in quantity of dispersing agent A increases the Suspensibility parameter. It is observed that ratio of dispersing agent A to dispersing agent B is in range of 1:1 to 5:2, the Suspensibility is greater than 70%. Ethylene thiourea is also is very less. After aging drop in active content is to the tune of 1.65%.
17

Example no 6:
Here formalin is used as stabilizer Percent on dry basis
Sodium ligno sulphonate 12.02
lomard 1.19
Maneb 76.14
HMT 3.47
Znso4 5.33
HCHO(37%) 0.33
Dextrose 1.52
100
Experimental procedure is same as example no 2
The following parameters relating to Mancozeb granules were determined before and after
aging at 54 ± 2°c for 14 days.

PARAMETERS Example A Before Aging Example A After Aging
Active content (% w/w) 75.4 72.08
Suspensibility %w/w 84.1 74.26
Wetting out time 3 sec 3 sec
Dust content 7mg 10 mg
Attrition resistance 96 95
PH (1% solution) 6.9 6.9
Moisture content (%w/w) 1.6 1.7
Ethylene thiourea 0.055% 0.13
18

When formalin is used as stabilizer then the drop in active is greater than 2.5%.
The novel formulation developed shows better bio-efficacy results when it compared with
Mancozeb 75% WP
TESTING
1) A study was conducted to evaluate the effect of Mancozeb 75% WDG on natural enemy
complex of tomato pests under field conditions of West Bengal. Design of the study was
RBD with six replications; carried out in a field where plants were moderately infested with
fruit borers and leaf miners.
Three different doses of Mancozeb 75% WDG were used viz 2 g/lt, 3 g/lt and 4g/lt along with an untreated control plot. The fungicidal sprays were done three times at intervals of ten days @ 700 Its water/ ha with a hand operated high volume sprayer. Observations were recorded 7 days after each round of applications from 45 leaves (three leaves each from 15 plants).
It was found that in all the treated plots, the presence of the natural enemies remained unaltered. In spite of three rounds of repeated applications, the plants never exhibited any phototoxic symptoms in any treated plots. So it was concluded from the trial that Mancozeb 75% WDG at the three doses used were completely safe to three important natural enemies of tomato fruit borer and leaf miner.
2) Mancozeb 75% WDG was tested against late blight of potato (variety - kufri
chandramukhi) for kharif season of year 2003. Chemicals used were : Mancozeb 75% WDG
0.20%, Mancozeb 75% WDG 0.25%, Mancozeb 75% WDG 0.30%, Mancozeb 75% WP
0.20% and copper oxychloride 0.25%. In a randomized block design study, three sprays
were done of each chemical with four replications each.
The mean results showed that Mancozeb 75% WDG at all concentrations tested, more effective against late blight of potato compared to Mancozeb 75% WP 0.20% and copper oxychloride 0.25%. Highest yield of the crop was recorded in the plot sprayed Mancozeb 75% WDG 0.3%, followed by an almost equal yield for Mancozeb 75% WDG 0.25% & Mancozeb 75% WDG 0.20%; this yield being significantly superior over yields of plots treated with the other chemicals and untreated control. No phytotoxicity or other harmful effects observed.
19

3) Bidhan Chandra Krishi Vishwavidyalaya carried out an evaluation of fungicides against
late blight of potato, early blight of tomato and powdery mildew of pea during Rabi and
summer season (2003-2004).
Chemicals used were : Mancozeb 75% WDG 0.20%, Mancozeb 75% WDG 0.25%,,
Mancozeb 75% WDG 0.30%, Mancozeb 75% WP
0.25%, Metalaxyl+Mancozeb 72% WP, Chlorothalonil 75% WP 0.25%, Zinc 75% WP
0.25%. In a randomized block design study, three sprays were done of each chemical with
three replications. Untreated control plot was sprayed with water only.
Results showed that application of fungicides reduced disease severity significantly as
compared to control. Best results were obtained with Mancozeb 75%WDG formulation at all
doses.
The Mancozeb WDG formulation was found to be better than Mancozeb WP formulation
with respect to its persistency and dispersibility.
No phytotoxicity could be observed even after 21 days of spray.
4) Bio-efficacy testing of Mancozeb 75% WDG was conducted during Autumn season 2002
by Centre for Plant Protection Studies, Tamilnadu against late blight of potato.
Chemicals used were : Mancozeb 75% WDG 0.20%, Mancozeb 75% WDG 0.25%,
Mancozeb 75% WDG 0.30%, Mancozeb 75% WDG 0.35%, Mancozeb 75% WP 0.25%.
In a randomized block design study, four sprays were done of each chemical at 10 days
intervals starting from 40 days after planting, with four replications. Untreated control plot
was sprayed with water only. Incidence of disease was graded on a scale of 0-9 and percent
disease index was calculated.
20

We Claim:
1) A process for preparation of Mancozeb water dispersible granular formulation by spray
drying at lower temperature comprising the steps of;
a) Making of Maneb slurry and charging with adjuvant to make it homogeneous;
b) Blending of slurry and then wet milling to get particle size of 2-4 microns;
c) Grinding the slurry in the wet milling mixed with binder, dispersing agent and adjuvant to obtain Mancozeb slurry containing solids in the range of 48-56 % in the post blending stage;
d) Spraying of slurry at inlet temperature ranging from 50-90 °C and drying the granules at a temperature of 60-80 °C;
e) Passing of the dried granules through sieve to obtain a product of particle size 150-850 microns.

2) The process as claimed in Claim 1 wherein, different stages of the grinding of the active and post blending of slurry with various additives, spraying of slurry and drying of granules is carried out in the same equipment.
3) The process as claimed in Claim 1 wherein, outlet temperature during spraying and drying is between 40-70°C.
4) The process as claimed in Cl^im 1 and 2 wherein, spraying and drying carried out in Fluisized Bed Equipment.
5) The process as claimed in Claim 1 wherein, formulation comprises dispersing agent and optionally fillers.
6) The process as claimed in Claim 5 wherein, surfactant agent comprises emulsifying agent, dispersing agent and wetting agent.
7) The process as claimed in Claim 6 wherein, the surfactant selected from anionic
surfactants and non-ionic surfactants.


8) The process as claimed in Claim 7 wherein, the anionic surfactant are selected from a group of surfactants such as sodium dodecyl benzene sulphoante, sodium, calcium or ammonium lignosulphoante, sodium formaldehyde condensates polymer salt, Naphthalene formaldehyde condensate and sodium salt.
9) The process as claimed in Claim 7 wherein, the non ionic surfactant are condensation products of ethylene oxide with alkyl phenols such as octal phenol and nonyl phenol.

10) The process as claimed in Claim 1 and 6 wherein, surfactant comprises at least one wetting agent such as those selected from a group of wetting agents such as alkyl naphthalene sulfonates, phosphate esters, and / or at least one dispersing agent such as those selected from the group of dispersing agents such as naphthalene condensates and ligno sulfonates.
11) The process as claimed in Claim 1 and 6 wherein the total content of surfactant ranges from 2 to 20% and preferably 3 to 15% by weight of the dry weight of the formulation.
12) The process as claimed in Claim 1 wherein, the formulation comprises adhesives selected from a group of adhesives such as starch syrup, dextrose, sucrose , dextrin , poly vinyl acetate and inert material such as kaolin or agents which promote the bursting of the granule-grains in water such as penta sodium triphosphate.
13) The process as claimed in Claim 1 wherein, formulation optionally comprises inert material preferably Kaolin.
14) The process as claimed in Claim 1 wherein, formulation optionally comprises burst promoting agents for bursting of the granule grain.
15) The process as claimed in Claim 14 wherein, the bursting agent is Penta Sodium Triphosphate in water.
16) The process as claimed in Claim 1 wherein, Mancozeb formulation comprises;


a) 2 to 4% binding agent;
b) 2 to 14% dispersing agent / wetting agent;
c) 0.2 to 2% para formaldehyde;
d) 2 to 7% zinc sulphate;
e) 3 to 5 % hexamethylene tetra mine;
f) 73.5 to 88% Maneb;
g) 0.2 to 1% sodium tripolyphosphate; and h)0.1to0.3%NopcoNXZ.
17) The process as claimed in Claim 1 and 16 wherein, the preferred Mancozeb
formulation consists essentially of;
a) 3 % of binding agent;
b) 10% of sodium ligno sulphonate ;
c) 0.36% of para formaldehyde;
d) 5.8% of zinc sulphate;
e) 2.35% of Hexamethylene tetra mine;
f) 78% of Maneb;
g) 0.2% of Defoamer;
h) 0.4% of disintegrating agent; and
i) 1% of sodium naphthalene sulphonate formaldehyde condensate.
18) The process as claimed in Claim 1 wherein, the pH required to carry out the process is 6.9 to 7.2
19) The process as claimed in Claim 1 wherein, the moisture content of the product before aging is less than 2.5%
20) Mancozeb water dispersible granular formulation obtained by the process of claims 1 to 17, comprising:

a) 2 to 4% binding agent;
b) 2 to 14% dispersing agent / wetting agent;
c) 0.2 to 2% para formaldehyde;


d) 2 to 7% zinc sulphate;
e) 3 to 5 % hexamethylene tetra mine;
f) 73.5 to 88% Maneb;
g)0.2tol% sodium tripolyphosphate; and h) 0.1 to 0.3% non-silicone oil
21) Mancozeb water dispersible formulation as claimed in claim 20, consisting essentially of;
a) 2 % of binding agent;
b) 10% of sodium ligno sulphonate;
c) 0.36% of para formaldehyde;
d) 5.8% of zinc sulphate;
e) 2.2% of Hexamethylene tetra mine;
f) 78% of Maneb;
g) 0.2% of Defoamer;
h) 0.4% of disintegrating agent; and
i) 1% of sodium naphthalene sulphonate formaldehyde condensate;