MXPA97009999A - Uniform mixes of granules pesticide - Google Patents

Abstract

A homogeneous mixture of solid granules of cylindrical shape of one or more having substantially uniform diameters of a longitudinal length no greater than eight times the diameter with the average length being 1.5 to 4 times the diameter and wherein the diameters vary from a group to another in no more than 3

Description

UNIFORM MIXES OF PESTICIDE GRANULES BACKGROUND OF THE INVENTION The present application relates to mixtures of pesticide granules of various cylindrical shape that do not segregate. Pesticide granules, which are granules dispersible in water, disintegrate in the water of a spray tank to form a fine dispersion of primary particles, which are then applied to the crops by means of spraying. Pesticide granules can also be completely soluble in water. Pesticide granules can also be applied dry. In agriculture, more than one pesticide is often needed to treat a particular crop. In such a case, granules containing a combination of pesticides can be prepared or alternatively prepared separate granules for each pesticide. It is desirable to apply a combination of pesticides simultaneously in a step when spraying crops instead of performing separate steps on the field with each pesticide. In the use of two or more water-dispersible granules each granule is added to the same spray tank after which they disintegrate and are homogeneously distributed in REF: 26013 the water that can be sprayed on the crop. However, adding individual particles to the spray tank is not totally satisfactory due to the inconvenience of measuring products separately and the risk of erroneous measurements increases. A single product containing all the necessary pesticides is preferred. Pesticide blending products in which each granule contains more than one pesticide are commercially available. However, for several markets, pesticides are needed in different combinations and relationships. This increases the number of products and leads to complicated manufacturing and storage problems. It could be advantageous to produce pesticide granules with a single active ingredient that can be combined with a different granular pesticide to form a mixture of granules in the desired ratio as a physical mixture before adding to a spray tank. The physical mixtures of individual granules of different sizes present the risk of segregation and therefore erroneous application when dispersed in parts. One solution to the problem of segregation with respect to water-dispersible granules is to pack the mixture as a "unit package" in which all the contents of the package are used in the spray tank. An example of a unit package is a water-soluble bag which simply is stirred in the spray tank filled with water after which the bag dissolves releasing the contents. Another example of a unit package is a bottle that contains only one dose. Although the unit package is a method for dealing with the problems associated with granule blends, such a package lacks flexibility in the dosage since all the contents of the package must be emptied at one time. Most of the water dispersible granules currently produced are "isodimensional", ie they are approximately spherical and are produced by granulation methods such as fluid bed drying, tray or disc, high cut, spray and the like, and also extrusion in paste in which the extrudate is subsequently treated to give an isodimensional shape (for example, WO 89/00079). The granules produced by these methods tend to have a high variability in the granule size distribution but can be sifted by sieving. To maximize productivity, the range of product sizes is as wide as possible and granules outside the desired product size distribution can be recycled or reworked. Even with the same type of process, there are tendencies from batch to batch and from product to product of variations in the distribution of granule sizes.

In FR 2,704,387 it has been suggested that to obtain a non-segregating mixture of granules, the ratio of average diameters of two categories of granules must be 10 or less. The normal product size distribution of the described granulation techniques typically falls within this range. However, to achieve the preferred ratio of 2 or less, a granular separation after production, extensive, is required. The data show that even if the diameter ratio is less than 2, a significant lack of homogeneity of the size segregation can result. It could be advantageous if a normal product size distribution was suitable for mixing in non-segregated mixtures without further separation by size.

BRIEF DESCRIPTION OF THE INVENTION The present invention pertains to mixtures of pesticide granules that remain homogeneous when stored, handled and distributed. It has been found that homogeneous mixtures of granules result when different granules of substantially similar size and shapes are mixed. Such mixtures that remain homogeneous make it possible to dispense or distribute the content in part and provide a reproducible composition.

The granules of the present invention have a similar size and are characterized by having a substantially cylindrical shape. What is meant substantially cylindrical, is similar to a rod or tube wherein the shape of the cross section may be circular, octagonal, rectangular, or any other conceivable shape and wherein the longitudinal surface is spiral, curved or straight. The longitudinal length of the substantially cylindrical granules of the invention is not greater than eight (8) times the diameter (width of the cross section at its widest point), preferably from 1 to 4 times the diameter with the average length being from 1.5 to 4.0 times the diameter. The diameters of the cylindrical granules in the mixture have a significant effect on the segregation and uniformity of the granule. Advantageously, the techniques for the manufacture of cylindrical granules by extrusion provide a high degree of control of the diameter of the granule thus allowing to equalize the diameters of the cylindrical granules in the normal course of production. There is no need for a size separation after production, extensive. The containers of the cylindrical granules mixtures of the present invention can therefore be made of two or more different pesticide granules and provide a non-segregating composition. The granules can be dispersible in water, soluble in water, and / or non-dispersible. Accordingly, a homogeneous mixture of solid granules comprising cylindrically shaped granules having a diameter that differs from one group of the mixture to another group by no more than 30% with longitudinal lengths no greater than eight (8) times has been discovered. the diameter with the average length being from 1.5 to 4.0 times the diameter. Thus, the present invention is directed to mixtures of pesticidal granules comprising cylindrically shaped granules, wherein a group of the mixture has a pesticide or pesticide content with a longitudinal length not greater than eight (8) times the diameter with the average length being 1.5 to 4.0 times the diameter and one or more different groups having another pesticide or inert content with a longitudinal length no greater than eight (8) times the diameter with the average length being 1.5 to 4.0 times the diameter , the diameter of each group differs from the other group by no more than 30%.

DETAILS OF THE INVENTION According to the present invention, the pesticidal granules of the invention may comprise a mixture of at least two sets of granules which differ in diameter from 0 to 30%, and have the required longitudinal length. A granule assembly may contain pesticide, the other set of granules may contain no pesticide or a different pesticide and additionally, for example, adjuvants. Pesticides refer to agriculturally active ingredients such as herbicides, fungicides, bactericides, insecticides, agents that inhibit the appetite of insects, acaricides, acaricides, nematocides, and plant growth regulators. Further in accordance with the present invention there is provided a mixture of granules of the invention, which may be contained in a different unitary package and be dosed flexibly in two or more uniform portions. The "container" refers to the container in which the mixture of granules is provided to the consumer, and includes containers typically used for this purpose such as bottles, bags and the like. However, even when the mixture of granules of this invention is not required, it could also be packaged in unit doses. Unit doses means an amount of the mixture of the invention to be added to a water spray tank. The packaging could be in the case of unit doses a water soluble polymer. The water-soluble polymer can be selected from polyethylene oxide, methylcellulose and polyvinyl alcohol with the polyvinyl alcohol being the preferred polymer. By uniform portions it is understood that the mixture will not vary in the pesticide test beyond a range that is acceptable to the regulatory agencies, which carefully monitor the agricultural compositions. It is important to recognize that the variability in a measurement of a physical mixture of granules is inversely proportional to the size of the sample taken. However, the acceptable variation in a sample composition can be as high as 10-15% depending on the absolute composition. In general, the pesticide test of each portion of the mixture constituting the invention should be within ± 5%, preferably ± 3%, of the marked composition of the product. The sources of assay variability include the uncertainty in the assay method itself. For granular mixtures, the assay variability increases when there are granules with a wide size distribution beyond the limits of the present invention. The cylindrical granules result from granulation techniques such as extrusion and granulation. Those techniques provide granules that are very consistent in size and shape. For the conventional pasta extrusion, the diameter is controlled (by the choice of the matrix) but the longitudinal lengths are determined by the breaking of the extruded strands in a drying step or after the drying step. For other granulation and extrusion techniques, both diameter and length can be precisely controlled. The techniques of extrusion and granulation can produce cylindrical granules that are consistent in size from batch to batch and even from product to product. Due to their shape, cylindrical granules can not be easily classified by traditional sieving. However, generally the extrusion process to form the cylindrical granules of the invention can produce substantially uniform longitudinal lengths. The weighted average lengths generally of 1.5 to 4 times the diameter contain lengths that can vary up to 8 times the diameter. It has been found that the diameter of the cylindrical granules has an effect on the homogeneity of the combination or mixture. The average diameter of the largest granules in the mixture is not more than about 30% larger than the average diameter of the smallest granules in the mixture. More preferably, the average diameter of the largest diameter granules in the mixture is not more than about 20% larger than the average diameter of the smaller diameter granules in the mixture. More preferably, the average diameters of all cylindrical granules differ by 0-10%. The absolute diameter of the cylindrical granules can be any suitable diameter, generally although the diameter is in the range of 0.4 to 10 mm and more typically in the range of 0.8 to 2 mm. In addition, differences in length can also affect the homogeneity of the cylindrical granules. The lengths of the cylindrical pesticidal granules of the present invention are from 1 to 8 times the diameter. Preferably, the lengths of the granules are from 1 to 4 times the diameter. Although the above discussion focused on water dispersible granules, it should be appreciated that the foregoing applies to non-dispersible granules. Examples of suitable pesticides may include, but are not limited to the following: herbicides such as acifluorfen, asulam, atracine, azafenidina, bensulfurón methyl, bentazón, bromacil, bromoxynil, hydroxybenzonitrile, chloramben, chlorimuron ethyl, chloroxuron, chlorsulfuron, chlortoluron, cyanamide, dazomet, desmedifan, dicamba, dichlorbenil, dichlorprop, diphenamid, dipropetrin, diuron, thiameturon, fenac , fenuron, fluometuron, fluridone, fomesafen, glyphosate, hexacinone, imazametabenz, imazaquin, imacetapir, ioxinil, isoproturon, isouron, isoxaben, carbutylate, lenacil, MCPA, MCPB, mefenacet, mefluidide, metabenzthiauron, metazole, metribuzin, metsulfuron methyl, monuron, naptalam, neburón, nitralín, norfluzarón, orizalín, perfluidona, fenmedifam, picloram, prometrín, pronamida, propanil, propacina, pirazón, rimsulfurón, sidurón, simacina, sulfentrazona, 2-chloro- (4, 6-dimetoxi pyrimidin-2-iltio) sodium enzoate, sulfometuron methyl, tebutiuron, terbacil, terbutilacine, terbutrin, thifensulfuron methyl, triclopyr, 2,4D, 2,4-DB, triasulfuron, tribenuron methyl, triflusulfuron methyl, pyrimisulfuron, ethyl pyrazolesulfuron, nicosulfuron, methyl ethamethyl sulfur, 2- [2,4-dichloro-5- [(2-propynyl) oxy] phenyl-5,6,7,8-tetrahydro-1,2,4-triazolo - [4, 3-a] -pyridin-3- (H) -one, sodium salt of 2- [[[[(4,6-dimethoxy-2-pyrimidinyl) amino] carbonyl] amino] sulfonyl] -6- Methyl (trifluoromethyl) -3-pyridinecarboxylate, N - [(4,6-dimethoxypyrimidin-2-yl) aminocarbonyl] -l-methyl-4- (2-methyl-2H-tetrazol-5-yl) -1H-pyrazole-5 -sulfonamide and N- [(4,6-dimethoxypyrimidin-2-yl) aminocarbonyl] -1-methyl-4-ethoxycarbonyl-5-pyrazole sulfonamide; fungicides such as carbendacim, thiuram, dodin, chloroneb, captan, fa oxadone, folpet, thiophanatemethyl, tiliabendazole, chlorothalonil, dichloran, captafol, iprodione, vinclozolin, kasugamycin, triadi enol, flutriafol, flusilazole, hexaconazole, and fenarimol; bactericides such as oxytetracycline dihydrate; acaricides such as hexatizox, oxythioquinox, dienochlor, and cyhexatin; and insecticides such as carbofuran, carbaryl, 7-chloro-2,5-dihydro-2- [[methoxycarbonyl) 4- (trifluoromethoxy) phenylamino) -carbonyl) inden- (1, 2-E) (1,3,4 ) oxadiacin-4A-methyl carboxylate, thiodicarb, deltamethrin, and tetrachlorvinfos. Especially preferred are sulfonylurea herbicides which are understood to include the entire class of herbicides containing the following and any closely related chemical functionalities: According to the present invention, a mixture of pesticide granules is provided which can be uniformly dosed thereby allowing the easy preparation of a wide range of mixing ratios to satisfy different markets and thus solve many manufacturing problems. inventories. In addition, granules with the normal product size distribution "as they were" can be used without the need for separation by - substantial size after production. The following examples are intended to illustrate but not limit the present invention.

EXAMPLE 1 Effect of the diameter of the cylindrical granule on the segregation Two 50/50 mixtures of cylindrical granules A and B were made, wherein the diameter of the granules was varied. The granules were prepared by pulp extrusion using a bench basket extruder, and the resulting extrudate was dried in a fluid bed dryer. The movement of the granules in the dryer provided the mechanism for the extrudate to break into smaller lengths, the average length of the granules was 2-3 times the diameter or width of the cross section. In each experiment, 50 g of granules containing approximately 50% pesticide were mixed with 50 g of Placebo granules that did not contain pesticide. The mixture was placed in a polyethylene bottle which was inverted until homogeneous and then stirred in a mechanical stirrer for 15 minutes. The mixture was then poured continuously into 10 aliquots of 10 g each. Each aliquot was homogenized by grinding in a powder and tested for the pesticide by standard CLAP techniques. The results are summarized below using the relative standard deviation (The Relative Standard Deviation is the standard deviation divided by the pesticide percent 100 times) as a means to compare the variation of our data that could be accepted by the regulatory agencies (generally 3 -5%) .

Active Granules A B Diameter (mm) 1.0 1.2 Average Length (mm) 2.1 2.5 Placebo Granules Diameter (mm) 1.0 1.0 Average Length (mm) 2.1 2.1 Diameter difference (%) 0 20 % of Pesticide (Average of 10 aliquots) 26.3 26.1 Relative Standard Deviation (%) 2.0 3.3 EXAMPLE 2 Effect of the length of the cylindrical granule on the segregation For this example, the current pesticide granules in discrete lengths were not readily available and instead cylindrical plastic beads of different colors were used, as follows: Black Silver Rose Gold Diameter (mm) 2.0 2.0 2.0 2.0 Length (mm) 6.4 5.0 5.0 3.2 Pearls / gram 26 33 33 50 The beads, of the same diameter and different lengths, were mixed in batches of 200 grams, bottled and agitated as in Example 1 and then poured into five aliquots of 40 grams. Each aliquot was "tested" by manually separating the beads by color and determining the total weight of each color. The results were the following.

Composition of the Mix Relative Standard Deviation 50% Silver + 50% Gold 3.7% 50% Pink + 50% Black 5% 3% 50% Silver + 50% Black 2.3% The relative lengths varied from 1: 1 for pearls of silver color + gold color to 2: 1 for pearls of pink color + black color. There was good homogeneity of the plastic beads.

COMPARATIVE EXAMPLE A Illustration of a mixture of isodimensional granules Two 50/50 mixtures of isodimensional granules A and B were made, where the relative average diameter (mesh size) of each set of granules varied. In each case, 50 g of active granules containing approximately 50% pesticide were mixed with 50 g of placebo granules which did not contain pesticide. The mixture was placed in a polyethylene bottle which was inverted until homogeneous, then stirred in a 15 minute mechanical stirrer. The mixture was then poured continuously into ten aliquots of 10 g each. Each aliquot was homogenized by grinding in a powder and analyzed by the assay using standard CLAP techniques. The results are summarized below.

Active Granules B Mesh Size -25 / + 30 -14 / + 60 Placebo Granules Mesh Size -35 / + 40 -14 / + 60 Diameter Ratio 1.7 5.6 Diameter Difference (%) 70 460 % of pesticide (Average of 10 23.9 23.5 aliquots) Relative Standard Deviation (%) 16.6 13.6 The granules in this example were granulated in a fluid bed. It can be seen that it is very difficult to equalize those granules in a mixture that can be dosed uniformly. The 14/60 mesh size is a typical product cut for commercial pesticide granules. Within this range, the distribution of granule sizes may vary from product to product and from batch to batch. Thus, even for mixtures of granules having the same nominal size distribution as in mixture B, there may be a substantial disuniformity in the dosage. The break in mesh size with the 14/60 mesh product distribution is as follows: Mesh Size% in Active% in Placebo 14-30 53 36 30-40 29 28 40-50 14 25 50-60 3 10 The distribution of the sizes within the 14/60 mesh interval reflects the distribution "as was done " The distribution was not deliberately adulterated. Other granulation techniques for producing isodimensional granules give ranges of equally wide sizes which also vary in distribution within the range of product size from batch to batch and from product to product.

COMPARATIVE EXAMPLE B Effect of the diameter of the cylindrical granule on the segregation A 50/50 mixture of cylindrical granules was made, wherein the relative diameter of the granules was varied.

The granules were prepared by pulp extrusion using a bench basket extruder, and the resulting extrudate was dried in a fluid bed dryer. The movement of the granules in the dryer provided the mechanism for the extrudate to break into smaller lengths, the average length of the granules was 2-3 times the diameter or width of the cross section. In this experiment, 50 g of granules containing approximately 50% pesticide were mixed with 50 g of placebo granules that did not contain pesticide. The mixture was placed in a bottle of polyethylene which was inverted until it was homogeneous and then inverted in a mechanical stirrer for 15 minutes. The mixture was then poured continuously into ten aliquots of 10 g each. Each aliquot was homogenized by grinding in a powder and tested for the pesticide by standard CLAP techniques. The results are summarized below.

Active Granules Diameter 1.2 Average Length 2.5 Granules of Placebo Diameter 0.8 Average Length 2.5 Diameter Difference (%) 50 % of Pesticide (Average of 10 aliquots) 26.0 Relative Standard Deviation (%) 10.6 it is noted that in relation to this date, the best method known by the applicant to carry out the aforementioned invention, is the conventional one for the manufacture of the objects to which it refers. Having described the invention as above, property is claimed as contained in the following:

Claims (10)

1. A substantial mixture of solid granules, which remains homogeneous when stored, handled and distributed, characterized in that it comprises two or more groups of granules of substantially cylindrical shape having substantially uniform diameters so that the average diameter of the largest granules is not more than 30% larger than the average diameter of the smallest granules of the mixture, where the longitudinal length of each group is 1 to 8 times the diameter of the granules with the average length being 1.5 to 4 times the diameter.

2. The mixture according to claim 1, characterized in that the longitudinal length of each group is 1.5 to 4 times the diameter of the granules.

3. The mixture according to claim 1, characterized in that the diameter of the granules differs from one group to any other in the mixture by no more than 20%.

4. The mixture according to claim 1, characterized in that the diameter of the granules differs from one group to any other in the mixture by no more than 10%.

5. The mixture according to claim 2, characterized in that the diameter of the granules differs from one group to any other in the mixture by no more than 20%.

6. The mixture in accordance with the claim 2, characterized in that the diameter of the granules differs from one group to any other in the mixture by no more than 10%.

7. The mixture according to any of the preceding claims, characterized in that it is packed in any suitable unit dose.

8. The mixture in accordance with the claim 7, characterized in that the package is a water soluble polymer.

9. The mixture in accordance with the claim 8, characterized in that the water-soluble polymer is selected from polyethylene oxide, methylcellulose and polyvinyl alcohol.

10. The mixture in accordance with the claim 9, characterized in that the water-soluble polymer is polyvinyl alcohol.