Stable aqueous compositions

Abstract

The present invention relates to an herbicidal composition particularly stable at lower temperatures. The present invention provides a stable herbicidal composition comprising at least one pesticide in its salt form and a crystal habit modifying system comprising an alkoxylated alcohol and a polymer. Further the invention relates to a stable herbicidal composition comprising at least two pesticides in their salt form and a crystal habit modifying system comprising an alkoxylated alcohol and a polymer.

Claims

1. A stable aqueous composition comprising, at least one herbicide in its salt form, wherein said herbicide is selected from the group consisting of acifluorfen, bentazone, and combinations thereof as the only herbicidal active ingredients in said composition and a crystal habit modifying system comprising an alkoxylated alcohol and a polymer, wherein the alkoxylated alcohol is butyl cellosolve; and wherein the polymer is selected from esters of polyalkoxylated alcohols, guar gum, xanthan gum, HP guar, and hydroxyethyl cellulose; wherein said polymer is present in an amount from about 0.1 to about 0.2% by weight of the composition; wherein said composition is stable at 10 C.

2. The composition of claim 1 comprising both acifluorfen and bentazone salts.

3. The composition of claim 2 comprising 1-25 wt. % acifluorfen salt and 1-50 wt. % bentazone salt based on the total weight of the composition.

4. The composition of claim 3 comprising 6-14 wt. % acifluorfen salt and 29-36 wt. % bentazone salt based on the total weight of the composition.

5. The composition of claim 1 wherein said composition includes 1-15 wt. % of said butyl cellosolve based on the total weight of the composition.

6. The composition of claim 5 wherein said composition includes 5-10 wt. % butyl cellosolve based on the total weight of the composition.

7. A method of controlling weeds said method comprising applying to a plant or a plant locus said stable aqueous composition of claim 1.

8. A stable aqueous composition comprising, 1-25 wt. % acifluorfen salt and 1-50 wt. % bentazone salt based on the total weight of the composition as the only herbicidal active ingredients in said composition and a crystal habit modifying system comprising an alkoxylated alcohol and a polymer, wherein the alkoxylated alcohol is butyl cellosolve; and wherein the polymer is selected from the group consisting of esters of polyakoxylated alcohols, HP guar, and hydroxyethyl cellulose; wherein said polymer is present in an amount from about 0.1 to about 0.2% by weight of the composition; and wherein said composition includes 1-15 wt. % of said butyl cellosolve based on the total weight of the composition; wherein said composition is stable at 10 C.

9. The composition of claim 8, wherein said composition includes 6-14 wt. % acifluorfen salt, 29-36 wt. % bentazone salt, and 5-10 wt. % butyl cellosolve based on the total weight of the composition.

10. A stable aqueous composition consisting of, at least one herbicide in its salt form, wherein said herbicide is selected from the group consisting of acifluorfen, bentazone, and combinations thereof as the only herbicidal active ingredients in said composition and a crystal habit modifying system consisting of an alkoxylated alcohol and a polymer, wherein the alkoxylated alcohol is butyl cellosolve; and wherein the polymer is selected from esters of polyalkoxylated alcohols, guar gum, xanthan gum, HP guar, and hydroxyethyl cellulose; wherein said polymer is present in an amount from about 0.1 to about 0.2% by weight of the composition; water; and optionally at least one surfactant, wherein said composition is stable at 10 C.

11. The composition of claim 10, wherein said optional surfactant is a nonionic surfactant.

12. The composition of claim 11, wherein said nonionic surfactant is selected from the group consisting of fatty alcohols having 10-24 carbon atoms; fatty acid alkoxylates; triglyceride alkoxylates; fatty acid amide alkoxylates; alkylene oxide adducts of alkynediols; sugar derivatives; amino sugars; amido sugars; polyacrylic derivatives; polymethacrylic derivatives; polyamides; modified gelatins; derivatized polyaspartic acid; surfactant polyvinyl compounds; modified PVP; polyol-based alkylene oxide adducts; polyglycerides and derivatives thereof.

13. The composition of claim 11 consisting of 1-25 wt. % acifluorfen salt and 1-50 wt. % bentazone salt based on the total weight of the composition.

14. The composition of claim 11 consisting of 1-15 wt. % of said butyl cellosolve based on the total weight of the composition.

Description

DETAILED DESCRIPTION

(1) Present invention is related to herbicidal compositions comprising at least one pesticide in its salt form which demonstrate excellent stability at low temperature and are bioefficacious. The present invention particularly relates to liquid compositions comprising at least two pesticides in their salt form and a crystal habit modifying system comprising an alkoxylated alcohol and a polymer which are stable at temperatures.

(2) Several viscosity modifiers are known to be used for various aqueous based agrochemical formulations. However, formulations suffer from the drawback of low temperature stability especially when using pesticide in its salt form active ingredients which are prone to solidify at low temperature. The formulations are either cloudy or have crystal formation or have solid separation when they are tested for stability at temperature below 0 C.

(3) Although the formulations are said to be bioefficacious in controlling weed, they are not practicable due to low temperature instability.

(4) Inventors of the present invention surprisingly found out that the problem of low temperature stability of such pesticides in their salt form can be overcome by using a crystal habit modifying system comprising an alkoxylated alcohol and a polymer.

(5) Accordingly there is provided a crystal habit modifying system comprising an alkoxylated alcohol and a polymer for stabilizing pesticidal salt solutions at low temperatures.

(6) In an embodiment of the present invention there is provided a composition comprising at least one pesticide in its salt form and a crystal habit modifying system comprising an alkoxylated alcohol and a polymer which exhibit excellent low temperature storage stability.

(7) In another embodiment there is provided a liquid herbicidal composition comprising at least two pesticides in their salt form and a crystal habit modifying system comprising an alkoxylated alcohol and a polymer.

(8) Low temperatures according to the present invention refer to a temperature below 10 C., preferably below 5 C., more preferable below 0 C., and most preferably it is 10 C.

(9) According to another embodiment of the present invention the crystal habit modifying system comprises an alkoxylated alcohol and a polymer.

(10) In a preferred embodiment the alkoxylated alcohol is selected from ethylene glycol, propylene glycol and butyl cellosolve.

(11) According to yet another preferred embodiment the alkoxylated alcohol is butyl cellosolve.

(12) In another embodiment of the present invention, the composition comprises from about 0.1 to 25% by weight of the alkoxylated alcohol preferably from about 1% to about 15% and more preferably from about 1% to about 10% by weight of the formulation.

(13) According to another embodiment of the present invention, the polymer is a crystal growth inhibitor, a viscosity modifier, crystal growth regulator, structuring agent or a rheology modifier.

(14) Examples of polymers include but not limited to modified cellulose derivatives, their co-polymers, modified starches, polyvinyl alcohols and derivatives, esters of alkoxylated polyols, clays, modified silica and natural gums such as guar gum, xanthan gum, HP guar, gelatin, dextrin, collagen and derivatives.

(15) According to a preferred embodiment of the present invention the thickener is selected from the group consisting of xanthan gum, guar gum, HP guar, hydroxyl ethyl cellulose and esters of alkoxylated polyols.

(16) In an embodiment of the present invention, the composition comprises from about 0.01% to about 0.2% by weight of the thickener preferably from about 0.05% to about 0.18% by weight of the formulation.

(17) According to an embodiment of the present invention, the composition may comprise at least one pesticide in its salt form selected from various classes of pesticides.

(18) In an embodiment of the present invention, the composition comprises at least one pesticide in its salt form selected from nitrophenyl ether herbicides, organophosphorus herbicides or benzothiadiazine herbicide.

(19) In another embodiment of the present invention the nitrophenyl ether herbicide is selected from acifluorfen, aclonifen, bifenox, chlomethoxyfen, chlornitrofen, etnipromid, fluorodifen, fluoroglycofen, fluoronitrofen, fomesafen, fucaomi, furyloxyfen, halosafen, lactofen nitrofen, nitrofluorfen and oxyfluorfen.

(20) In an embodiment of the present invention the organophosphorus herbicide is selected from amiprofos-methyl, amiprophos, anilofos, bensulide, bilanafos, butamifos, clacyfos, fosamine, glufosinate, glufosinate-P, glyphosate and piperophos.

(21) In another embodiment of the present invention the benzothiadiazine herbicide is bentazone.

(22) According to another embodiment of the present invention the preferred nitrophenyl ether herbicide is acifluorfen.

(23) In another embodiment of the present invention, there is provided a combination of at least two pesticides in their salt form.

(24) In an embodiment of the present invention, the combination of two pesticides in their salt form comprises nitrophenyl ether herbicides and benzothiadiazine herbicides.

(25) According to another embodiment of the present invention, the two pesticides in their salt form are acifluorfen and bentazone.

(26) In an embodiment of the present invention the composition comprises from about 0.1% to about 30% by weight of nitrophenyl ether herbicide preferably from about 1% to about 25% by weight of the formulation.

(27) In another embodiment of the present invention, the composition comprises from about 0.1% to about 60% by weight of benzothiadiazine herbicide preferably from about 1% to about 50% by weight of the formulation.

(28) In an embodiment of the present invention there is provided a composition comprising acifluorfen, bentazone and a crystal habit modifying system wherein the crystal habit modifying system comprises butyl cellosolve and hydroxyethyl cellulose.

(29) The composition comprises from about 1% to about 25% by weight of acifluorfen, from about 1% to about 50% by weight of bentazone, from about 1% to about 15% by weight of butyl cellosolve and from about 0.01% to about 0.2% by weight of hydroxyethyl cellulose.

(30) In another embodiment of the present invention, there is provided a composition comprising acifluorfen, bentazone and a crystal habit modifying system wherein the crystal habit modifying system comprises butyl cellosolve and esters of alkoxylated polyols.

(31) The composition comprises from about 1% to about 25% by weight of acifluorfen, from about 1% to about 50% by weight of bentazone, from about 1% to about 15% by weight of butyl cellosolve and from about 0.01% to about 0.2% by weight of esters of alkoxylated polyols.

(32) In yet another embodiment of the present invention, there is provided a composition comprising acifluorfen, bentazone and a crystal habit modifying system wherein the crystal habit modifying system comprises butyl cellosolve and xanthan gum.

(33) The composition comprises from about 1% to about 25% by weight of acifluorfen, from about 1% to about 50% by weight of bentazone, from about 1% to about 15% by weight of butyl cellosolve and from about 0.05% to about 0.2% by weight of xanthan gum.

(34) According to an embodiment of the present invention, there is provided a composition comprising acifluorfen, bentazone and a crystal habit modifying system wherein the crystal habit modifying system comprises butyl cellosolve and guar gum.

(35) The composition comprises from about 1% to about 25% by weight of acifluorfen, from about 1% to about 50% by weight of bentazone, from about 1% to about 15% by weight of butyl cellosolve and from about 0.05% to about 0.2% by weight of guar gum.

(36) According to an embodiment of the present invention, there is provided a composition comprising acifluorfen, bentazone and a crystal habit modifying system wherein the crystal habit modifying system comprises butyl cellosolve and HP guar.

(37) The composition comprises from about 1% to about 25% by weight of acifluorfen, from about 1% to about 50% by weight of bentazone, from about 1% to about 15% by weight of butyl cellosolve and from about 0.05% to about 0.2% by weight of HP guar.

(38) In an embodiment of the present invention there is provided a composition comprising glufosinate, glyphosate and a crystal habit modifying system wherein the crystal habit modifying system comprises butyl cellosolve and esters of alkoxylated polyols.

(39) The composition comprises from about 1% to about 35% by weight of glufosinate, from about 1% to about 50% by weight of glyphosate, from about 1% to about 15% by weight of butyl cellosolve and from about 0.05% to about 0.2% by weight of esters of alkoxylated polyols.

(40) The aqueous compositions according to the present invention may further comprise other agronomically suitable excipients such as surfactants, solvent, fertilizer, pH modifiers, suspending agents, spray droplet modifiers, pigments, antioxidants, foaming agents, light-blocking agents, compatibilizing agents, antifoam agents, sequestering agents, neutralizing agents, corrosion inhibitors, dyes, odorants, spreading agents, penetration aids, micronutrients, emollients, lubricants, sticking agents, dispersing agents, antimicrobial agents, and the like. In an embodiment of the present invention, the surfactants may be selected from nonionic surfactants. Examples of nonionic surfactants are: fatty alcohols having 10-24 carbon atoms with 0-60 EO and/or 0-20 PO and/or 0-15 BO in any order; fatty acid alkoxylates and triglyceride alkoxylates; fatty acid amide alkoxylates; alkylene oxide adducts of alkynediols; sugar derivatives such as amino sugars and amido sugars; polyacrylic and polymethacrylic derivatives; polyamides such as modified gelatins or derivatized polyaspartic acid; surfactant polyvinyl compounds such as modified PVP; polyol-based alkylene oxide adducts; polyglycerides and derivatives thereof.

(41) The process for preparing compositions according to the present invention is not particularly limiting. The salts of active ingredients are prepared according to processes known in the art.

(42) According to a preferred embodiment of the present invention, the composition was prepared as follows:

(43) The active ingredients was mixed in an empty reactor with calculated amounts of water and sodium hydroxide under stirring and heated to 75 C. The temperature was maintained at 75 C. for 24 hours. The reaction mixture was cooled to 35 C. and then charged butyl cellosolve and hydroxyethyl cellulose along with other customary adjuvants. Stirred for 1 hour, and was filtered.

(44) In an embodiment of the present invention there is provided a method to control unwanted plants or to influence the growth of plants by treating said plants in the field with a composition comprising at least one pesticide in its salt form and a crystal habit modifying system comprising an alkoxylated alcohol and a polymer.

(45) The invention shall now be described with reference to the following specific examples. It should be noted that the examples appended below illustrate rather than limit the invention and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the present invention. The formulation obtained is clear and no haziness or solidification is observed at 54 C., 25 C., 14 C. and 0 C. after 7/14 days as per CIPAC guidelines (MT 39.3), indicating that the composition is stable. Sub-zero stability test has been checked by keeping samples at 10 C. for 14 days.

EXAMPLES

Example 1

(46) A composition of acifluorfen sodium according to the present invention was prepared as follows:

(47) TABLE-US-00001 Ingredients % (w/w) Aciflourfen sodium 20.1 Butyl celloslove 8.5 HP guar 0.1 Water q.s

(48) The composition was prepared by the following manner:

(49) Aciflourfen sodium was mixed in an empty rector with butyl cellosolve, HP guar and other adjuvants in required quantity. The mixture was stirred for an hour and then filtered.

Example 2

(50) A composition of acifluorfen sodium and bentazone sodium according to the present invention was prepared as follows:

(51) TABLE-US-00002 Ingredients % (w/w) Aciflourfen sodium 13.4 Benatazone sodium 29.2 Butyl celloslove 6.0 Esters of alkoxylated polyols 0.15 Nonionic surfactant 5.0 Water q.s

Example 3

(52) A composition of glufosinate ammonium and glyphosate isopropyl amine salt according to the present invention was prepared as follows:

(53) TABLE-US-00003 Ingredients % (w/w) Glufosinate ammonium 16.0 glyphosate isopropyl amine salt 20.2 Butyl celloslove 6.0 Esters of alkoxylated polyols 0.15 Nonionic surfactant 5.0 Water q.s

(54) The stability studies of the compositions are illustrated in Tables 1-4.

(55) TABLE-US-00004 TABLE 1 Polymer/ Compo- Active Alkoxylated crystal sition ingredient alcohol inhibitor Observation Observation sample in salt % by % by % by at ambient Observation below 0 C. no form weight weight weight temp. at 10-0 C. (up to 10 C.) 1 A 20.1 C-8.5 0.0 clear hazy crystal 2 B 44 C-8.5 0.0 clear hazy crystal 3 A:B 13.4:29.2 C-1.5 0.0 clear crystal crystal 4 A:B 13.4:29.2 C-5 0.0 clear crystal crystal 5 A:B 13.4:29.2 C-12 0.0 hazy crystal crystal 6 A:B 13.4:29.2 C-15 0.0 Layer separation A: acifluorfen, B: bentazone, C: butyl cellosolve

(56) From the above table it has been found that though the compositions were stable at ambient temperatures, they failed at low temperatures.

(57) TABLE-US-00005 TABLE 2 Compo- Active Alkoxylated Crystal sition ingredient alcohol inhibitor Observation Observation sample in salt % by % by % by at ambient Observation below 0 C. no form weight weight weight temp. at 10-0 C. (up to 10 C.) 1 A:B 13.9:30.0 C:D-0:6.5 0.0 clear crystal crystal 2 A:B 13.9:30.0 C:E-0:5.0 0.0 clear crystal crystal 3 A:B 13.9:30.0 C:E - 3.0:5.0 0.0 clear crystal crystal 4 A:B 13.9:30.0 C-1.5 H: 0.3 clear crystal crystal 5 A:B 13.9:30.0 C:I - 1.5:4.0 J: 0.2 clear crystal crystal 6 A:B 13.9:30.0 C:I - 1.5:4.0 K: 0.2 clear crystal crystal A: acifluorfen, B: bentazone, C: butyl cellosolve, D: propylene glycol, E: Ethylene glycol, H: Agsole Ex, I: tetrahydrofurfuryl alcohol, J: Rhodafac rs-610, K: Atlox AL-3382

(58) It has been noted by the inventors of the present invention that compositions comprising alkoxylated alcohols, known antifreeze agents and/or known crystal inhibitors, crystal formation was observed at or below 0 C. as evident from table 2.

(59) TABLE-US-00006 TABLE 3 Compo- Active Alkoxylated Crystal Observation Observation sition ingredient alcohol inhibitor at below 0 C. sample in salt % by % by % by ambient Observation (up to no form weight weight weight temp. at 10-0 C. 10 C.) 1 A 20.1 0.0 H-0.2 clear crystal crystal 2 B 44 0.0 J-0.2 clear crystal crystal 3 A:B 13.9:30.0 0.0 H-0.2 clear crystal crystal 4 A:B 13.9:30.0 0.0 J-0.2 clear crystal crystal A: acifluorfen, B: bentazone, H: Agsole Ex, J: Rhodafac rs-610, K: Atlox AL-3382

(60) It has further been further noted by the inventors of the present invention that compositions comprising the known crystal inhibitors were not solving the problem of low temperature stability as crystal formation was observed at low temperatures as evident from table 3.

(61) TABLE-US-00007 TABLE 4 Compo- Active Alkoxylated Observation Observation sition ingredient alcohol Polymer at below 0 C. sample in salt % by % by % by ambient Observation (up to no form weight weight weight temp. at 10-0 C. 10 C.) 1 A 20.1 C-8.5 F-0.1 clear clear clear 2 B 44 C-9 L-0.1 clear clear clear 3 A:B 13.4:29.2 C-6.0 L-0.15 clear clear clear 4 A:B 13.4:29.2 C-6.0 G-0.2 clear clear clear 5 A:B 8.0:36.0 C-5.0 G-0.15 clear clear clear 6 A:B 6.4:30.6 C-6.0 G-0.10 clear clear clear 7 A:B 13.4:29.2 C-5.0 G-0.05 clear clear hazy 8 A:B 13.4:29.2 C-5.0 F-0.2 clear clear clear 9 A1:B1 16.0:20.2 C-6.0 L-0.15 clear clear clear A: acifluorfen, B: bentazone, A1: glufosinate ammonium, B1: Glyphosate isopropyl amine salt, C: butyl cellosolve, F: HP guar, G: Hydroxy ethyl cellulose, L: esters of alkoxylated polyols

(62) As table 4 indicates inventors of the present invention found out that low temperature stability of aqueous formulation of a pesticide in its salt form or combination of two such active ingredients can be achieved by using a crystal habit modifying system comprising an alkoxylated alcohol and a polymer. Samples were found to be stable at temperatures up to 10 C. It was further noted that in case of sample no. 7 wherein the amount of polymer was very low, the sample appeared to be hazy at 10 C.

(63) Although the present invention has been disclosed in terms of a preferred embodiment, it will be understood that numerous additional modifications and variations could be meet thereto without departing from the scope of the invention as defined by the following claims: