Claims:WE CLAIM:

1. A storage stable composition of an active ingredient system comprising:
(a) a fungicidally effective amount of sulphur in an amount from 30% to 85% by weight of the composition and a fungicidally effective amount of tebuconazole in an amount from 1% to l0%, by weight of the total composition and
(b) a dispersant system comprising:
(i) sodium lignosulfonate or sulfonated aromatic polymer, sodium salt in an amount upto 13% by weight of the composition; and
(ii) a salt of naphthalene sulphonic formaldehyde condensate in an amount from 1% to 5% by weight of the total weight of the composition.

2. The composition as claimed in claim 1, wherein the sulphur is present in an amount of 70% of total weight of the composition and tebuconazole is present in an amount of 4.5% of total weight of the dry granules.

3. The composition as claimed in any one of the preceding claim, wherein said composition is formulated as a water dispersible granule or as a wettable powder.

4. The stable composition as claimed in any one of the preceding claim, further comprising one or more active ingredients selected from plant growth regulators, herbicides, and/or pesticides, for example insecticides, fungicides, acaricides, nematocides, miticides, rodenticides, bactericides, molluscicides and bird repellants.
, Description:This application is divided out of Indian Application No. 1720/MUM/2009 filed on 28/07/2009. We pray that the instant application be ante-dated to the date of filing of the parent application.

Field of the Invention

The present invention relates to an agrochemical formulation comprising sulphur and tebuconazole. More particularly, the present invention relates to a highly dispersible solid granular formulation comprising sulphur and tebuconazole and a process for preparing such compositions.

Background of the Invention

The challenge involved in developing commercially acceptable products containing agriculturally active compounds in combination continues to increase due to the rapid emergence of more complex customer and regulatory requirements. These agricultural compositions must exhibit excellent chemical stability and must also maintain a high level of physical stability under a severe range of storage and use conditions especially when used in combination.

US5198231, assigned to Bayer, claims a fungicidal composition comprising a synergistic fungicidally effective amount of wettable sulfur in combination with tebuconazole in a ratio of about 1:50. However, this patent fails to appreciate the sedimentation and caking problems faced by formulations comprising this combination due to the high sulphur density present within such formulations. The sediment so formed on storage is quite difficult to redisperse even after vigorous stirring.

US6677399B2, assigned to ICI PLC GB, teaches a water dispersible solid granular agrochemical formulation. The disclosed formulation is typically in the form of wettable powders and particularly has an average particle size from 5 to 50 µm. The disclosed formulations also include water dispersible granules having an average particle size of from 200 µm to 5 mm. This patent discloses a dispersing agent, which is preferably a water dispersible styrene (meth) acrylic copolymer. However, this patent does not acknowledge the sedimentation problem that is observed when a high amount of sulphur is present in combination with tebuconazole in a formulation. Thus, there exists a need in the art to develop a formulation that overcomes the sedimentation problem associated with the conventional formulations comprising sulfur active ingredient in combination with tebuconazole and yet remains highly dispersible in a required medium.

This invention attempts to provide such a solid granular formulation of sulphur and tebuconazole wherein the granules remain highly dispersible in water.

Dispersions of sulphur and tebuconazole may be prepared according to any known procedure in the prior art. It has been found that the sulphur active component generally has an undesirable tendency to settle on standing to form hard caked precipitates which are difficult to break up and redisperse. Dispersions of sulphur prepared with the aid of the protective colloids formerly employed are also objectionable for some purposes because they are generally flocculated or precipitated by acids or heavy metal ions. The inventors of the present invention have observed that the precipitation and sedimentation or caking of sulphur aggravates in the presence of tebuconazole. This sediment is difficult to redisperse even after using super dispersants in the formulation and vigorously shaking the container before use. This led the present inventors to find a solution to the sedimentation or caking problem that sulphur and tebuconazole composition faced.

Thus, it was believed that there existed a need in the art for a dispersant system to develop good water dispersible granules comprising sulphur and tebuconazole active ingredients. The desired formulation was required to provide good dispersion and suspension properties after extended storage (ageing) of the dry granules.

Thus all these challenges have now surprisingly been met by an invention set out immediately below.

Advantages of the Invention:

Accordingly, it is one advantage of the present invention to provide a physicochemically stable water dispersible solid granular agrochemical formulation of sulphur in combination with tebuconazole.

Further advantage of the present invention is to provide a stable water dispersible solid granular agrochemical formulation typically in the form of wettable powders or water dispersible granules including sulphur in combination with tebuconazole as active components.

Another advantage of the present invention is to provide a stable water dispersible solid granular agrochemical formulation having excellent dispersibility and sprayability.

Yet another advantage of the invention is to prepare a composition of water dispersible solid granular agrochemical formulation having enhanced bioefficacy.

Yet another advantage of the present invention is to provide an improved dispersant system which affords improved water dispersible granules comprising sulfur and tebuconazole active ingredients such that said granules possess good dispersion and suspension properties even after prolonged storage.

Yet another advantage of the present invention is to provide an improved dispersant system that is highly eco-friendly.

Yet another advantage of the present invention is to reduce the fire hazards that normally occur during milling sulphur while formulating sulphur and tebuconazole.

Yet another advantage of the present invention is to provide a spray mix comprising a solid granular agrochemical formulation dispersed in water.
Further advantage of the invention is to provide an improved method of treating plants or a locus surrounding the plant to render it fungicide free.

These and other advantages of the present invention would be apparent from the description of the invention set out hereinafter.

Summary of the Invention

Accordingly, in one aspect, the present invention provides a stable water dispersible solid granular agrochemical formulation comprising (a) a fungicidally effective amount of sulphur active ingredient in combination with a fungicidally effective amount of tebuconazole active ingredient component; and (b) a dispersant system comprising at least one styrene acrylic copolymer in an amount of at least 10% by total weight of the formulation in combination with at least one salt of naphthalene sulphonic formaldehyde condensate in an amount of at least 1% by total weight of the formulation.

In another aspect, the present invention provides a process for the preparation of a stable water dispersible solid granular agrochemical formulation of sulfur and tebuconazole active ingredients, said process comprising:
(a) mixing fungicidally effective amounts of said sulfur and tebuconazole active ingredients with a dispersant system comprising at least one styrene acrylic copolymer in an amount of at least 10% by total weight of the formulation in combination with at least one salt of naphthalene sulphonic formaldehyde condensate in an amount of at least 1% by total weight of the formulation, said components being mixed in the presence of a sufficient quantity of water to obtain a paste;
(b) granulating said paste by a method selected from extrusion, fluidized bed granulation, pan granulation and spray drying; and
(c) drying the granules obtained thereby to obtain said granular formulation.

In another aspect, the present invention provides a process for the preparation of a stable water dispersible solid wettable powder formulation of sulfur and tebuconazole active ingredients, said process comprising:
(a) mixing fungicidally effective amounts of said sulfur and tebuconazole active ingredients with a dispersant system comprising at least one styrene acrylic copolymer in an amount of at least 10% by total weight of the formulation in combination with at least one salt of naphthalene sulphonic formaldehyde condensate in an amount of at least 1% by total weight of the formulation; and
passing the mixture through a centrifuge mill using suitable screen.

Detailed Description of the Invention

The agrochemical compositions are generally prepared using one or more adjuvants sometimes in specific combinations to provide optimum physicochemical stability and optimum biological activity. Sometimes higher the concentration of the active agrochemical and its associated adjuvants, greater is the probability that the stability of the formulation may be disturbed and one or more component separates out, for example as a discrete phase. In general, the separation of a discrete phase from an agrochemical is highly undesirable, particularly when the formulation is sold in bulk containers. In these circumstances it is virtually impossible to re-homogenize the formulation and to achieve even distribution of the components on dilution and spraying.

The present inventors have surprisingly found that agrochemicals in the form of water dispersible granules including a styrene acrylic copolymers in an amount of at least 10% w/w of the formulation and a salt of naphthalene sulphonic formaldehyde condensate in an amount of at least 1% w/w of the formulation imparts excellent dispersibility and suspension properties after extended storage (ageing) of the dry granules. It was found that the desired dispersibility and suspensibility was not attained in formulations without a styrene acrylic copolymers or less than about 10% w/w of said styrene acrylic copolymer and without a salt of naphthalene sulphonic formaldehyde condensate or with less than about 1% of said salt of naphthalene sulphonic formaldehyde condensate.

In an embodiment, the preferred granular formulation according to the present invention is in the form of water dispersible granules or wettable powders.

The term "effective amount" as used herein denotes a quantity of active ingredient which when applied to the site in a conventional manner causes the occurrence of desired effects. The quantity of active ingredients comprised within the composition of the present invention depends on the degree of activity desired to be achieved by the administration of the composition of the present invention and may be suitably determined by a person skilled in the art.

The inventors of the present invention have further surprisingly found that the addition of a combination of a styrene acrylic copolymer in combination with a salt of naphthalene sulphonic formaldehyde condensate among various other dispersant systems tested, resulted not only in an excellent dispersion system (Refer table 1), but also provides a stable formulation of sulphur and tebuconazole. Thus, it can be concluded that a combination of the specific quantities of styrene acrylic copolymers and a salt of naphthalene sulphonic formaldehyde condensate was critical to obtain a granular formulation having a desired suspensibility and dispersion.

It was found that when the formulations according to the present invention were prepared without the salt of naphthalene sulfonic formaldehyde condensate, the resulting formulation displayed poor dispersion with only around 30% suspensibility (refer table 2) Moreover, formulations comprising said naphthalene sulfonic formaldehyde condensate alone in the absence of styrene acrylic copolymer could not be formulated as granular compositions (refer Table 3). Thus, it was concluded that at least 10% by weight of the formulation of a styrene acrylic copolymer and at least about 1% naphthalene sulphonic formaldehyde condensate was critical to maintain desired dispersibility and suspensibility of the granular compositions according to the present invention..
Table 1:
(Different surfactant combinations used with Salt of naphthalene sulphonic formaldehyde condensate)
Active Ingredients % w/w % w/w % w/w % w/w % w/w % w/w
1 Sulphur 71.72 71.72 71.72 71.72 71.72 71.72
2 Tebuconazole 5.26 5.26 5.26 5.26 5.26 5.26
3 Kaolin 4.82 4.82 4.82 4.82 4.82 4.82
4 Silica 3 3 3 3 3 3
5 Styrene acrylic copolymer 13 - - - - -
6 Sodium Lignosulphonate - 13 - - - -
7 Stepsperse DF500 - - 13 - - -
8 Calcium Lignosulphonate - - - 13 - -
9 Ammonium Lignosulphonate - - - - 13 -
10 Sulfonated aromatic polymer,
Sodium salt 13
11 Salt of naphthalene sulphonic formaldehyde condensate 2 2 2 2 2 2
12 Silicon oil defoamer 0.2 0.2 0.2 0.2 0.2 0.2
13 Suspensibility
(Physicochemical properties) 83 60 55 57 52 73

Table 2
(Experiments carried out using different weight % of styrene acrylic copolymer omitting the salt of naphthalene sulphonic formaldehyde condensate)

Common name
of compound Comp
% W/W
1 Comp
% W/W
2 Comp
% W/W
3 Comp
% W/W
4 Comp
% W/W
5 Comp
% W/W
6 Comp
% W/W
7
1 Sulphur Tech. 71.72 71.72 71.72 71.72 71.72 71.72 71.72
2 Tebuconazole 5.26 5.26 5.26 5.26 5.26 5.26 5.26
3 Kaolin 4.82 4.82 4.82 4.82 4.82 4.82 4.82
4 Silica Q.S Q.S Q.S Q.S Q.S Q.S Q.S
5 styrene acrylic
copolymer 10 12 13 14 15 16 17
6 Naphthalene
Sulphonic
formaldehyde
condensate 0 0 0 0 0 0 0
7 ( Silicon
oil defoamer 0.2 0.2 0.2 0.2 0.2 0.2 0.2
8 Suspensibility Less than 30% Less than 30% Less than 30% Less than 30% Less than 30% Less than 30% Less than 30%
9 Dispersion Poor Poor Poor Poor Poor Poor Poor

Table 3
(Experiments carried out using different %w/w of salt of naphthalene sulphonic formaldehyde condensate omitting styrene acrylic copolymer)

Common name
of compound Composition
% W/W
1 Composition
% W/W
2 Composition
% W/W
3 Composition
% W/W
4 Composition
% W/W
5 Composition
% W/W
6 Composition
% W/W
7
1 Sulphur Tech. 71.72 71.72 71.72 71.72 71.72 71.72 71.72
2 Tebuconazole 5.26 5.26 5.26 5.26 5.26 5.26 5.26
3 Kaolin 4.82 4.82 4.82 4.82 4.82 4.82 4.82
4 Silica Q.S Q.S Q.S Q.S Q.S Q.S Q.S
5 styrene
acrylic copolymer 0 0 0 0 0 0 0
6 Naphthalene
sulphonic
formaldehyde
condensate 0.5 1 2 3 4 5 6
7 ( Silicon
oil
defoamer 0.2 0.2 0.2 0.2 0.2 0.2 0.2
8 Suspensibility NA NA NA NA NA NA NA
9 Dispersion
NA NA NA NA NA NA NA
10. Granule
formulation Granule not possible Granule not possible Granule not possible Granule not possible Granule not possible Granule not possible Granule not possible

Moreover, it was also found that when the compositions of the present invention were prepared as solid formulations comprising sulphur and tebuconazole, there were no physical changes observed in the formulation on storage.

The styrene acrylic copolymer dispersant preferably has a molecular weight of from 750 to 20000, more desirably from 1000 to 10000 and particularly from 1500 to 5000. The polymeric dispersant can be used as the free acid or as a salt. In practice, the form present in a formulation will be determined by the acidity of the formulation. Desirably, the formulation will be near neutral and so most of the acid groups will be present as salts. The cations in any such salt can be alkali metal, particularly sodium and/or potassium, ammonium, or amine, including alkanolamine such as ethanolamine, particularly tri-ethanolamine.

The polymeric dispersants used in this invention are desirably free from solvent which might interfere with the active ingredient or cause the granules to stick together. It is useful if the polymeric dispersant can be used satisfactorily in a variety of different granulation processes. Further desirably the polymeric dispersant is heat stable, readily soluble in cold water from the solid dispersible granule (satisfactory polymeric dispersants need not be readily cold water soluble from the bulk solid form) and non gelling.

The inclusion of monomers having strongly acidic substituent groups in the polymeric dispersant can provide improved dispersion of the solid granular form of the agrochemical formulations when dispersed in hard water, particularly water having a hardness above 500 ppm e.g. up to 1000 ppm, up to 2000 ppm or even up to 5000 ppm.

The polymeric dispersants can be made by free radical initiated polymerisation, e.g. using a peroxide or a redox initiator, particularly by solution polymerisation, of the constituent monomers, optionally also with a chain transfer agent such as an alkyl mercaptan which acts to control the molecular weight of the polymer. Such processes for the preparation of these dispersants are conventionally known in the art and are not particularly limiting.

The water dispersible styrene acrylic copolymer component used in the formulation according to the present invention is, for convenience, referred to herein as a polymeric dispersant. The repeating units in the copolymer are conveniently considered as residues of monomer components.

The acrylic acid monomer(s) can be methacrylic acid, crotonic acid or a mixture of two or more of these. The (meth) acrylic acid monomer(s) can be or include (meth) acrylic monomers which are derivatives of (meth) acrylic acid which include strong acid, especially sulphate acid or sulphonic acid groups (or their salts). Examples of such monomers include acrylamido methyl propyl sulphonate (AMPS) and (meth) acrylic acid isethionate. When present such strong acid modified monomers usually form from 1 to 30 mole %, more usually 2 to 20 mole %, and desirably from 5 to 15 mole %, of the acrylic 0acid monomers in the copolymer.

The styrene monomer(s) can be, and desirably is, styrene as such or a substituted styrene particularly a hydrocarbyl, desirably alkyl, substituted styrene, in which the substituent(s) are on the vinyl group or on the aromatic ring of the styrene e.g. a-methyl styrene and vinyl toluene. As with the (meth) acrylic acid monomer, the styrene monomer can be or include styrene monomers including strongly acid, particularly sulphonic acid substituents. When present such strong acid modified monomers usually form 1 to 30 mole %, more usually 2 to 20 mole %, and desirably from 5 to 15 mole %, of the styrene monomers in the copolymer.

The improved dispersing system used in the formulation of the invention preferably includes a co-dispersant selected from naphthalene sulfonate formaldehyde condensates, which term shall mean naphthalene sulphonate formaldehyde condensates and its salts, lignosulfonates, maleic anhydride copolymers and condensed phenolsulphonic acid and their salts. The amount of styrene (meth) acrylic copolymer(s) within the compositions of the present invention varies from about at least 10% by weight of the composition, more preferably in the range of about 10-17% by weight of the composition and most preferably in the range of 12-14% by weight of the composition. The amount of the salt of naphthalene sulfonate formaldehyde condensates used in combination with the styrene acrylic copolymer is used in an amount of at least about 1% by the weight of the composition or more preferably in the range of about 2-5% by weight of the composition.

The following table 4 illustrates the results when a salt of naphthalene sulphonic formaldehyde condensate was used in an amount of about 1% by weight of the formulation with varying amounts of the styrene acryclic copolymer ranging from about 6% to about 17% by weight. The resulting formulations were tested for their physico-chemical parameters such as suspensibility and dispersibility and the results were tabulated as hereunder. The dispersibility was visually determined and reported as very poor when the dispersed phase is less than 50% v/v, , poor when the dispersed phase is in the range of 50-70%, good when the dispersed phase is in the range of 70 – 80%, very good when the dispersed phase is in the range of 80-85% and excellent when the dispersed phase is above 85%. It was found that formulations comprising at least about 12% of a salt of naphthalene sulphonic formaldehyde condensate provided superior suspensibility and dispersibility.

Table 4

Common name
of compound Comp.
% W/W
1 Comp.
% W/W
2 Comp.
% W/W
3 Comp.
% W/W
4 Comp.
% W/W
5 Comp.
% W/W
6 Comp.
% W/W
7 Comp.
% W/W
8 Comp.
% W/W
9 Comp.
% W/W
10
Sulphur Tech. 71.72 71.72 71.72 71.72 71.72 71.72 71.72 71.72 71.72 71.72
Tebuconazole 5.26 5.26 5.26 5.26 5.26 5.26 5.26 5.26 5.26 5.26
Kaolin 4.82 4.82 4.82 4.82 4.82 4.82 4.82 4.82 4.82 4.82
Silica 11 9 8 7 5 4 3 2 1 0
Styrene
(meth)acrylic
copolymer 6 8 9 10 12 13 14 15 16 17
Salt of
Naphthalene
Sulphonic
Formaldehyde
condensate 1 1 1 1 1 1 1 1 1 1
Silicon oil
Defoamer 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2
Suspensibility
Physicochemic
property Approx
25% Approx.
30% 54.4 74 76.12 80.05 84 84.90 Approx
89% Approx
89%

Dispersion V.Poor V.Poor Poor Poor Good Good V.Good V.Good Excel Excel

The following table 5 illustrates the results when a salt of naphthalene sulphonic formaldehyde condensate was used in an amount of about 2% by weight of the formulation with varying amounts of the styrene acryclic copolymer ranging from about 6% to about 17% by weight. The resulting formulations were tested for their physico-chemical parameters such as suspensibility and dispersibility and the results were tabulated as hereunder. It was found that formulations comprising at least about 10% of a salt of naphthalene sulphonic formaldehyde condensate provided superior suspensibility and dispersibility.

Table 5
Common name
Of compound Comp.
% W/W
1 Comp.
% W/W
2 Comp.
% W/W
3 Comp.
% W/W
4 Comp.
% W/W
5 Comp.
% W/W
6 Comp.
% W/W
7 Comp.
% W/W
8 Comp.
% W/W
9 Comp.
% W/W
10
Sulphur Tech. 71.72 71.72 71.72 71.72 71.72 71.72 71.72 71.72 71.72 71.72
Tebuconazole 5.26 5.26 5.26 5.26 5.26 5.26 5.26 5.26 5.26 5.26
Kaolin 4.82 4.82 4.82 4.82 4.82 4.82 4.82 4.82 4.82 3.82
Silica 10 8 7 6 4 3 2 1 0 0
Styrene
(meth)acrylic
copolymer 6 8 9 10 12 13 14 15 16 17
Salt of
Naphthalene
Sulphonic
Formaldehyde
condensate 2 2 2 2 2 2 2 2 2 2
Silicon oil
Defoamer 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2
Suspensibility
Physicochemical
property Approx
25% Approx.
30% Approx.
60% 79.22 81.75 83.0 85.13 88.82 Approx 8 90% Approx 8 90%
Dispersion V.poor V.Poor Poor Good V.Good V.Good Excel Excel. Excel. Excel.

The following table 6 illustrates the results when a salt of naphthalene sulphonic formaldehyde condensate was used in an amount of about 3% by weight of the formulation with varying amounts of the styrene acryclic copolymer ranging from about 6% to about 17% by weight. The resulting formulations were tested for their physico-chemical parameters such as suspensibility and dispersibility and the results were tabulated as hereunder. It was found that formulations comprising at least about 10% of a salt of naphthalene sulphonic formaldehyde condensate provided superior suspensibility and dispersibility.

Table 6
Common name
Of compound Comp.
% W/W
1 Comp.
% W/W
2 Comp.
% W/W
3 Comp.
% W/W
4 Comp.
% W/W
5 Comp.
% W/W
6 Comp.
% W/W
7 Comp.
% W/W
8 Comp.
% W/W
9 Comp.
% W/W
10
Sulphur Tech. 71.72 71.72 71.72 71.72 71.72 71.72 71.72 71.72 71.72 71.72
Tebuconazole 5.26 5.26 5.26 5.26 5.26 5.26 5.26 5.26 5.26 5.26
Kaolin 4.82 4.82 4.82 4.82 4.82 4.82 4.82 4.82 3.82 2.82
Silica 9 7 6 5 3 2 1 0 0 0
Styrene
(meth)acrylic
copolymer 6 8 9 10 12 13 14 15 16 17
Salt of
Naphthalene
Sulphonic
Formaldehyde
condensate 3 3 3 3 3 3 3 3 3 3
Silicon oil
Defoamer 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2
Suspensibility
Physicochemical
property Appro
25% Appro
30% Appro
60% 81.35 83.39 84.23 88.41 89.58 Approx 89% Approx 89%
Dispersion
V.poor
V.Poor
Poor
V.Good
V.Good
V.Good
Excel
Excel
Excel
Excel

The following table 7 illustrates the results when a salt of naphthalene sulphonic formaldehyde condensate was used in an amount of about 4% by weight of the formulation with varying amounts of the styrene acryclic copolymer ranging from about 6% to about 17% by weight. The resulting formulations were tested for their physico-chemical parameters such as suspensibility and dispersibility and the results were tabulated as hereunder. It was found that formulations comprising at least about 10% of a salt of naphthalene sulphonic formaldehyde condensate provided superior suspensibility and dispersibility.

Table 7

Common name
Of compound Comp.
% W/W
1 Comp.
% W/W
2 Comp.
% W/W
3 Comp.
% W/W
4 Comp.
% W/W
5 Comp.
% W/W
6 Comp.
% W/W
7 Comp.
% W/W
8 Comp.
% W/W
9 Comp.
% W/W
10
Sulphur Tech. 71.72 71.72 71.72 71.72 71.72 71.72 71.72 71.72 71.72 71.72
Tebuconazole 5.26 5.26 5.26 5.26 5.26 5.26 5.26 5.26 5.26 5.26
Kaolin 4.82 4.82 4.82 4.82 4.82 4.82 4.82 3.82 2.82 1.82
Silica 8 6 5 4 2 1 0 0 0 0
Styrene
(meth)acrylic
copolymer 6 8 9 10 12 13 14 15 16 17
Salt of
Naphthalene
Sulphonic
Formaldehyde
condensate 4 4 4 4 4 4 4 4 4 4
Silicon oil
Defoamer 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2
Suspensibility
Physicochemi cal
property Less
than
25% Appro
30% Appro
60% 83.87 85.69 86.33 89.22 89.33 Appro
89% Appro
89%
Dispersion V.poor V.Poor Poor V.Good Excel Excel Excel Excel Excel Excel

The following table 8 illustrates the results when a salt of naphthalene sulphonic formaldehyde condensate was used in an amount of about 5% by weight of the formulation with varying amounts of the styrene acryclic copolymer ranging from about 6% to about 17% by weight. The resulting formulations were tested for their physico-chemical parameters such as suspensibility, dispersibility and wetting time and the results were tabulated as hereunder. It was found that formulations comprising at least about 10% of a salt of naphthalene sulphonic formaldehyde condensate provided superior suspensibility and dispersibility.

Table 8

Common name
Of compound Comp.
% W/W
1 Comp.
% W/W
2 Comp.
% W/W
3 Comp.
% W/W
4 Comp.
% W/W
5 Comp.
% W/W
6 Comp.
% W/W
7 Comp.
% W/W
8 Comp.
% W/W
9 Comp.
% W/W
10
Sulphur Tech. 71.72 71.72 71.72 71.72 71.72 71.72 71.72 71.72 71.72 71.72
Tebuconazole 5.26 5.26 5.26 5.26 5.26 5.26 5.26 5.26 5.26 5.26
Kaolin 4.82 4.82 4.82 4.82 4.82 4.82 3.82 2.82 1.82 0.82
Silica 7 5 4 3 1 0 0 0 0 0
Styrene
(meth)acrylic
copolymer 6 8 9 10 12 13 14 15 16 17
Salt of
Naphthalene
Sulphonic
Formaldehyde
condensate 5 5 5 5 5 5 5 5 5 5
Silicon oil
Defoamer 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2
Suspensibility
Physicochemical
property Less
Than
25% 29.14 Approx.
60% 84.88 86.31 88.67 89.41 89.62 Approx
89% Approx .
89%
Dispersion * V.Poor V.Poor Poor V.Good Excel Excel Excel Excel Excel Excel

The following table 9 illustrates the results when a salt of naphthalene sulphonic formaldehyde condensate was used in an amount of about 6% by weight of the formulation with varying amounts of the styrene acryclic copolymer ranging from about 6% to about 17% by weight. The resulting formulations were tested for their physico-chemical parameters such as suspensibility and dispersibility and the results were tabulated as hereunder. It was found that formulations comprising 6% of styrene methacrylic copolymer consistently failed suspensibility and dispersibility tests irrespective of the amount of the salt of naphthalene sulfonate formaldehyde condensate.

Table 9

Common name
of compound Comp.
% W/W
1 Comp.
% W/W
2 Comp.
% W/W
3 Comp.
% W/W
4 Comp.
% W/W
5 Comp.
% W/W
6 Comp.
% W/W
7 Comp.
% W/W
8 Comp.
% W/W
9 Comp.
% W/W
10
Sulphur Tech. 71.72 71.72 71.72 71.72 71.72 71.72 71.72 71.72 71.72 71.72
Tebuconazole 5.26 5.26 5.26 5.26 5.26 5.26 5.26 5.26 5.26 5.26
Kaolin 4.82 4.82 4.82 4.82 4.82 3.82 2.82 1.82 0.82 0
Silica 6 4 3 2 0 0 0 0 0 0
Styrene
(meth)acrylic
copolymer 6 8 9 10 12 13 14 15 16 17
Salt of
Naphthalene
Sulphonic
Formaldehyde
condensate 6 6 6 6 6 6 6 6 6 6
Silicon oil
Defoamer 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.02
Suspensibility
Physicochemical
property 27 Appro
30% 61.1 72.3 74 75 76 77 78 78
Dispersion * V.Poor V.poor Poor Poor Poor Poor Poor Poor Poor Poor

The following table 10 illustrates the results when a salt of naphthalene sulphonic formaldehyde condensate was used in an amount of about 7% by weight of the formulation with varying amounts of the styrene acryclic copolymer ranging from about 6% to about 16% by weight. The resulting formulations were tested for their physico-chemical parameters such as suspensibility and dispersibility and the results were tabulated as hereunder. It was found that formulations comprising 7% of styrene methacrylic copolymer consistently failed suspensibility and dispersibility tests irrespective of the amount of the salt of naphthalene sulfonate formaldehyde condensate.

Table 10

Common name
Of compound Comp.
% W/W
1 Comp.
% W/W
2 Comp.
% W/W
3 Comp.
% W/W
4 Comp.
% W/W
5 Comp.
% W/W
6 Comp.
% W/W
7 Comp.
% W/W
8 Comp.
% W/W
9 Comp.
% W/W
10
Sulphur Tech. 71.72 71.72 71.72 71.72 71.72 71.72 71.72 71.72 71.72 71.72
Tebuconazole 5.26 5.26 5.26 5.26 5.26 5.26 5.26 5.26 5.26 5.26
Kaolin 4.82 4.82 4.82 4.82 3.82 2.82 1.82 0.82 0 0
Silica 5 3 2 1 0 0 0 0 0 0
Styrene
(meth)acrylic
copolymer 6 8 9 10 12 13 14 15 16 16.02
Salt of
Naphthalene
Sulphonic
Formaldehyde
Condensate 7 7 7 7 7 7 7 7 7 7
Silicon oil
Defoamer 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.02 0.0
Suspensibility
Physicochemical
property 27 Appro
30% 61.1 64.2 67.9 72.9 74.8 75.0 76.5 77.9
Dispersion * V.Poor V.Poor V.Poor V.Poor Poor Poor Poor Poor Poor Poor

In other embodiments, the formulations according to the present invention may additionally include a further dispersant used in combination with the improved dispersant system according to the present invention. The additional dispersant may be preferably selected from but not limited to polyvinylpyrrolidone (PVP), polyvinyl alcohol (PVOH), phosphate esters such as the tristeryl phenol based phosphate esters available as Soprophor FL, carbomethoxycellulose (CMC), starch, alginate, gum arabic, sorbitol, sucrose and mixtures thereof.

In another embodiment, said further dispersant is present in an amount of from about 0 to about 5% by weight of the total dispersant.

The composition of the present invention may additionally contain one or more further active ingredients selected from plant growth regulators, herbicides, and/or pesticides, for example insecticides, fungicides, acaricides, nematocides, miticides, rodenticides, bactericides, molluscicides and bird repellants. Usually, the active will be a water insoluble or immiscible material, although granules can be made including water soluble active materials. Specific examples of further included active ingredients include:

Herbicides: including triazines such as Atrazine {6-chloro-N-ethyl-N'-(1-methylethyl)-1,3,5-triazine-2,4-diamine, and Prometryn {N,N'-bis(1-methylethyl)-6-(methylthio)-1,3,5-triazine)-2,4-diamine}, substituted ureas such as Diuron {N'-(3,4-dichlorophenyl)-N,N-dimethylurea}, sulphonyl ureas such as metsulfuron-methyl {2-[[[[(4-methoxy-6-methyl-1,3, 5triazin-2-yl) amino]carbonyl]amino]sulfonyl]benzoate}, triasulfuron {2-(2-chloroethoxy)-N-[[(4-methoxy-6-methyl-1,3,5-triazin-2-yl) amino] carbonyl]benzenesulfonamide}, tribenuron-methyl {methyl 2-[[[[(4-methoxy-6-methyl-1,3,5triazin-2-yl)methylamino]carbonyl]amino]sulfonyl]benzoate} and chlorsulfuron {2-chloro-N-[[(4-methoxy-6-methyl-1,3,5triazin-2-yl) amino]carbonyl]benzenesulfonamide}, bis-carbamates such as Phenmedipham {3-[(methoxycarbonyl)amino]phenyl (3-methylphenyl)carbamate};

Fungicides: including thiocarbamates, particularly alkylenebis(dithiocarbamate)s, such as Maneb {[1,2-ethanediylbis-[carbamodithiato](2-)]manganese} and Mancozeb {[[1,2-ethanediyl-bis[carbamodithiato]](2-)]manganese mixture with [[1,2-ethanediylbis[carbamodithiato]](2-)]zinc}, strobilurins such as azoxystrobin {methyl (E)-2-[[6-(2-cyanophenoxy)-4-pyrimidinyl]oxy]-a-(methoxymethylene)benzeneacetate} and kresoxim-methyl {(E)-a-(methoxyimino)-2-[(2-methylphenoxy)methyl]benzeneacetic acid methyl ester} , dicarboximides such as iprodione {3-(3,5dichlorophenyl)N-isopropyl-2, 4dioxo imidazolidine-1-carboxamide}; azoles such as propiconazole {1-[2-(2,4-dichloro-phenyl)-4-propyl-1,3-dioxolan-2-yl-methyl-1H-1,2,4-triazole} , and tebuconazole {(RS)-1-p-chlorophenyl-4,4-dimethyl-3-(1H-1,2,4-triazole-1-ylmethyl)pentan-3-ol}; halophthalonitriles such as chiorothalonil {2,4,5,6-tetrachloro-1,3-dicyanobenzene}; and inorganic fungicides such as Copper hydroxide {Cu(OH) 2};

Insecticides: including benzoyl ureas such as Diflubenzuron {N-[[(4-chlorophenyl) amino] carbonyl]-2,6-difluorobenzamide)}; and carbamates such as carbaryl {1-naphthyl methylcarbamate};

Acaricides including: tetrazines such as Clofentezine {3,6-bis(2-chlorophenyl)-1,2,4,5-tetrazine}.

Among water soluble active materials, non-selective herbicides, particularly N-(phosphono-methyl) glycine type herbicides such as glyphosate and sulphosate {respectively the iso-propyl-amino and trimethylsulphonium salts of N-phosphonomethyl glycine} and phosphinyl amino acids such as glufosinate {2-amino-4-(hydroxymethylphosphinyl) butanoic acid}, particularly as the ammonium salt. Such water soluble actives can be used as the sole active in water dispersible granules, but more usually, they will be used in combination with water insoluble or immiscible actives in multi-active formulations.

In an embodiment, the granules can further include solid support, filler or diluent material(s) which are desirably inert to the agrochemically active material, but which are readily dispersible in water, if necessary in conjunction with dispersing agents. They may also have the benefit of reducing granule dry clumping and the disintegration rate (on addition to water) and can also be used to adjust the active ingredient concentration. Examples include clays such as kaolin (china clay) and bentonite clays, which may be natural bentonites or modified e. g. activated bentonites, synthetic and diatomaceous silicas, calcium and magnesium silicates, titanium dioxide, aluminium, calcium or magnesium carbonate, ammonium, sodium, potassium, calcium or barium sulphate, charcoal, starch, including modified starches such as alkyl and carboxyalkyl starches, cellulose, such as microcrystalline cellulose, and cellulose derivatives such as carboxyalkyl cellulose, and mixtures of two or more such solid support, filler, diluent materials.

The agrochemical formulation of the present invention may additionally include adjuvants, particularly surfactant adjuvants, especially non-ionic surfactants, such as alcohol alkoxylates e.g. ethoxylates, particularly of C8 to C18 alcohols which can be linear, branched or linear/branched mixtures; alkylamine alkoxylates e.g. ethoxylates, particularly of C 8 to C 18 alkyl amines; sorbitol and sorbitan fatty acid, particularly C8 to C18 fatty acid, esters and their ethoxylated derivatives; and alkyl, particularly C6 to C14 alkyl, polysaccharides. Solid adjuvants may be included directly in the formulation. When the adjuvant is a liquid, then often simple direct incorporation is not appropriate because the adjuvant will often represent a relatively high proportion of the total weight of the granule. For example, typical weight ratios of adjuvant to agrochemical active range from 1:3 to 10:1. The inclusion of such a large amount of liquid may adversely affect the properties of the granule e.g. by making the granules sticky. This problem can be avoided by adsorbing the liquid adjuvant in or adsorbing it on a solid support e.g. silica or diatomaceous earth, which can be solid support, filler or diluent material as mentioned above, or by including it as a clathrate especially an urea clathrate.

Further surfactants can be included particularly as wetting agents to speed up granule wetting and disintegration on mixing with water. Examples of wetting agents include nonionic surfactants such as alcohol ethoxylates for example of C9 to C15, particularly primary, alcohols, which may be linear or branched, particularly mono-branched, ethoxylates with from 5 to 30 moles of ethylene oxide; and alkoxylates of such alcohols particularly mixed ethoxylate/propoxylates which may be block or random mixed alkoxylates, typically containing from 3 to 10 ethylene oxide residues and from 1 to 5 propylene oxide residues, particularly where the polyalkoxylate chain is terminated with propylene oxide unit(s); polyoxyethylene/polyoxypropylene copolymers, particularly block copolymers, such as the Synperonic PE series of copolymers and Atlas G 5000 available from Uniqema, and alkyl polysaccharides; anionic surfactants e.g. isethionates, such as sodium cocoyl isethionate, naphthalene sulphonic acids or sulphosuccinates. Mixtures of such wetting agents can also be used. Although some wetting agents are liquid, the amounts used are generally not so large as to give rise to problems with granule stickiness. However, if desired, the wetting agents can be used in a form in which they are adsorbed on solid support such as silica or diatomaceous earth, which can be solid support, filler or diluent material as mentioned above. For solid wetting agents granule stickiness does not generally limit the amount that can be used even without using a support.

Preferably, the total amount of dispersing agent or combinations thereof used in the granules of this invention varies from about 14% to about 25% by weight of the dry granules.

The total amount of agrochemically active sulphur material will typically be used in an amount of 30%-85%, more particularly 70% by weight of the dry granule. Similarly fungicidally effective amount of tebuconazole typically be used in an amount 1%-10%, more particularly 4.5%by weight of the dry granules.

Disintegrating agents can also be included to speed granule disintegration on mixing with water e.g. in a spray mix tank. Suitable materials include readily soluble materials such as inorganic water soluble salts e.g. sodium chloride, nitrate salts etc., and water soluble organic compounds such as urea (water soluble matrix materials may thus serve also as disintegrating agents), which dissolve thus opening up the granule structure. More active disintegration effects can be achieved using materials which swell or are effervescent on contact with water.

Humectants can be included, especially to aid water retention during granule formulation. Examples of suitable materials include polyoxyethylene/polyoxypropylene copolymers, particularly block copolymers, such as the Synperonic PE series of copolymers available from Uniqema. The non-ionic surfactants mentioned above as adjuvants may also act as humectants.

Particularly when the granules are made additional components may include lubricants such as stearates e.g. magnesium stearate, or boric acid, anti-adherence additives and glidants.

Other components that may be included are penetrating agents; antifoams; safeners such as Bitrex; pigments and/or dyes; anti-caking additives; sequestrants; and adhesives.

The preferred solid granular composition according to the present invention may be a water dispersible granular formulation or a wettable powder formulation.

In another aspect, the present invention provides a process for the preparation of a stable wettable powder formulation of sulfur and tebuconazole active ingredients, said process comprising:
(a) mixing fungicidally effective amounts of said sulfur and tebuconazole active ingredients with a dispersant system comprising at least one styrene acrylic copolymer in an amount of at least 10% by total weight of the formulation in combination with at least one salt of naphthalene sulphonic formaldehyde condensate in an amount of at least 1% by total weight of the formulation; and
(b) passing the mixed powder through a centrifuge mill using suitable screen to obtain the resultant wettable powder formulation.

In yet another aspect, the present invention provides a process for the preparation of a stable water dispersible solid granular agrochemical formulation of sulfur and tebuconazole active ingredients, said process comprising:
(a) mixing fungicidally effective amounts of said sulfur and tebuconazole active ingredients with a a dispersant system comprising at least one styrene acrylic copolymer in an amount of at least 10% by total weight of the formulation in combination with at least one salt of naphthalene sulphonic formaldehyde condensate in an amount of at least 1% by total weight of the formulation, said components being mixed in the presence of a sufficient quantity of water to obtain a paste;
(b) granulating said resultant paste by a method selected from extrusion, fluidized bed granulation, pan granulation and spray drying; and
(c) drying the granules obtained thereby to obtain said water dispersible granular formulation.

Typically, the granules are made by mixing the formulation components including sufficient water to form a paste having suitable rheology for granulation, forming granules from the mixture and then drying the granules. Desirably the formulation includes a filler and when used the composition of the formulation will usually be adjusted so that the composition can readily be formed into granules. A wide variety of granulation methods can be used, including extrusion, fluidized bed granulation, pan-granulation, spray drying. Powder granular formulations can be converted into granules of larger particle size by such processing methods or by adding moderate amount of water to the powder and mixing to agglomerate the powder into larger granules.

In extrusion granulation the formulation will usually be made up as a pasty material that can readily extruded typically to give spaghetti like strands which are usually subsequently broken up into granules e.g. during drying.

In fluidized bed granulation a mixture of the powdered components is fluidized in a fluidized bed and the mixture is sprayed with an aqueous mixture or solution of the liquid components. The particles agglomerate in the bed to form granules which are dried in the bed.

In pan granulation, the solids are tumbled in a rotating inclined vessel and the liquid components sprayed on the particles which agglomerate to form granules which are dried either in the vessel or subsequently, e.g. in a fluidized bed drier.

In spray drying a flowable slurry or solution of all the components of the formulation is made and passed to a spray drier where the slurry or solution is atomised and dried. If necessary, a desired size range of particles is selected from the spray dried product and/or the product can be agglomerated e.g. in a fluidized bed, to form a granulate of the desired particle size range.

Particularly where the granulation method directly produces granules having a range of particle sizes, the granule product can be sieved or otherwise classified, to yield a desired limited particle size range. This is a convenient way to exclude fine particles and thus to make a granular product which is non-dusting at the point of manufacture.

The granules of the agrochemical formulation of this invention typically can have a range of particle sizes. Granules having a moderate to large particle size, often described as water dispersible granules, can have an average particle size (based on spheres of equal volume) of from 200 µm to 1 cm more usually from 200 µm to 5 mm. As particle size and the rate of disintegration are usually inversely related, it is desirable that the particle size is not too great and average particle sizes of up to 2 mm, especially in the range 200 µm to 2 mm are used in water dispersible granule formulations for agrochemicals. An average particle size less that 200 µm is preferably not adopted as it will tend to be associated with higher proportions of fine particles that may give rise to dust. When the granules are made by extrusion, they typically have a diameter of from 0.5 to 2 mm but may retain a strand like form having a length of up to 1 cm, but more usually up to about 5 mm. Strand like granules of this type have minimum size, usually in two dimensions considerably less than their length and typically in the range 0.5 to 2 mm. When the granules are made by tableting, the shape of the granules will primarily be set by the shape of the tablet mould and typical average granule sizes may be from 0.5 mm up to 7.5 mm more usually up to 5 mm. The other methods of making granules will typically yield particles having a low aspect ratio and will usually be made or selected to have an average particle size of from 200 µm to 2 mm, more usually 500 µm to 1.5 mm. As is indicated above, the particle size distribution will generally be chosen so that the presence of finer particles, particularly those less than about 100 µ m is minimized. Accordingly the granules desirably include not more than about 2 weight %, desirably not more than 1 weight %, of particles having a size of less than 200 µm and desirably not more than 0.5% weight %, particularly not more than 0.1 weight %, of particles having a size of less than 50 µm.

The following examples are for purposes of illustration only and are not intended to limit the scope of the present invention.

The best mode of making and using the present invention are described in the following examples. These examples are given only to provide direction and guidance in how to make and use the invention, and are not intended to limit the scope of the invention in any way.

EXAMPLE - 1

The composition comprises Sulfur, tebuconazole, Styrene acrylic copolymer, Diisopropyl naphthalene Sulfonate sodium, Kaolin and silica by weight of the composition.

Examples using different grades of dispersants (Polymeric Dispersant)
Metasperse 550 S- Styrene Acrylic copolymer.
Morwet EFW- Na-alkyl naphthalene sulfonate blend

Recipe:
Sulphur -----------------71.72
Tebucanozole---------- 5.26
Metasperse 550 S----- 13.0
Morwet EFW ----------2
SAG 1572---------------0.2
Ppt.Silica--------------- -3.0
Kaolin -------------------QS
Process Extrude Basket
Dispersibility nice dispersion
Suspensibility(%w/w)
Ambient
14D AHS
83.42
80.65
Chemical stability till shelf life No Degradation
Persistent foam
10 ml after 1 minute
pH of 1 % aqueous suspension 8.50

Process: The composition exemplified herein can be processed in the following manner to get the granular product.

(A) Roller/Basket extrusion:

In a suitable pre blender the specified amount of sulphur,tebuconazole, styrene acrylic copolymer, diisopropyl naphthalene sulphonate sodium, kaolin and silica are taken and blended for the required time to get a uniform mix.

In an air jet mill, the premix is milled to get a particle size of 100% less than 30 micron. Any other suitable micronizer can also be adopted for the said process. The air jet material is reblended. The material is then charged in a ribbon blender/plough shear mixer or in any other suitable dough making equipment and 12-18% water is sprinkled over it to get a dough. The dough is then extruded through a roller/basket extruder. Water content of the extruded material is then reduced by drying in a fluid bed dryer or any other suitable dryer to the extent of below 1% by weight.

(B) Spray drying technology
In a suitable pre blender the specified amount sulphur, tebuconazole, styrene acrylic copolymer, diisopropyl naphthalene sulphonate sodium, kaolin and silica are taken and blended for the required time to get a uniform mix. An aqueous slurry is prepared which contains 40-60% by weight of pre blended material. The slurry is sand milled to get particle size of 100% less than 12 micron. This slurry can be spray dried in a suitable spray dryer to get free flowing powder.

(C) Pan Granulation:
In a suitable pre blender the specified amount of sulphur, tebuconazole, styrene acrylic copolymer, diisopropyl naphthalene sulphonate sodium, kaolin and silica are taken and blended for the required time to get a uniform mix.
In an air jet mill, the premix is milled to get a particle size of 100%less than 30 micron. Any other suitable micronizer can also be adopted for the said process. The air jet material is reblended. This reblended material is loaded in a pan granulator and required amount of water is sprinkled over it to get a spherical granules. After sizing the granules formed are dried in a suitable dryer to reduce the moisture content to lass than 1 % by weight.

Table 11

The Composition of the present invention is compared with the market sample and the physicochemical parameters are compared
Parameters Marketed Sample The present invention
(UPL’s sample)
Recipe: Sulphur
Tebucanozole
Alkyl naphthalene phenol condensate
Alkyl naphthalene sulphonate
Sodium Polycarboxylate Sodium lignosulphonate
China clay Sulphur
Tebucanozole
Metasperse 550 s
Supragil WP
SAG 1572
Ppt.Silica
Kaolin
Dispersibility :
Poor dispersion Good dispersion
Suspensibility(%w/w)
Ambient :
14D AHS
62.23%
62.10%
84.58%
82.35

Any other Observation Flocculation is observed No any Flocculation

It can be authenticated that the physicochemical stability of market sample is compared with the present invention and it is evident that the dispersibility and suspensibility of the invention disclosed in this specification is much better than the suspensibility and dispersibility of market sample.

Also there is no flocculation observed in the composition of the present invention.
The wetting time of UPL’s composition is almost half than the wetting time of the market sample.

Table 12
The reproducibility of the composition of the present invention is also checked to ensure the physicochemical stability
Parameters Batch 1 Batch 2 Batch 3 Batch 4
Process Basket Extrusion Basket
Extrusion Basket Extrusion Basket Extrusion
Suspensibility(%w/w)
Ambient
14D AHS
84.58%
82.35
84.68%
83.36
83.48%
83.45
85.38%
84.55
Chemical stability till shelf life No Degradation No Degradation No Degradation No Degradation
Persistent foam 9 ml after 1 minute)
14 ml after 1 minute
15 ml 16 ml 14 ml
Wetting time (Sec) 5 sec 5 sec 6 sec 7 sec
pH of 1 % aqueous suspension 8.45 8.45 8.44 8.75
Bulk Density (gm/cc) 0.778 0.777 0.771 0.774
Particle Size (µm) d(0.1) = 0.138
d(0.5) = 0.193
d(0.9) = 3.579
d(0.95)=7.586
d(1.00) = 26.303
d(0.1) = 0.125
d(0.5) = 0.185
d(0.9) = 4.356
d(0.95)=9.658
d(1.00) = 30.256
D(0.1) = 0.256
d(0.5) = 0.289
d(0.9) = 3.579
d(0.95)=7.56
d(1.00) = 28.303 d(0.1) = 0.189
d(0.5) = 0.156
d(0.9) = 3.458
d(0.95)=7.586
d(1.00) = 27.303

Wherein the aforegoing reference has been made to components having known equivalents, then such equivalents are herein incorporated as if individually set forth. Accordingly, it will be appreciated that changes may be made to the above described aspects and embodiments of the invention without departing from the principles taught herein. Additional advantages of the present invention will become apparent for those skilled in the art after considering the principles in particular form as discussed and illustrated. Thus, it will be understood that the invention is not limited to the particular embodiments described or illustrated, but is intended to cover all alterations or modifications which are within the scope of the invention.