MXPA00010018A - Improved extrusion process - Google Patents

Abstract

The present invention provides an improved process for making extruded granules containing an agriculturally active ingredient. The extrusion process is more efficient, without reduction in biological effect of the active ingredient, if an organosilicone surfactant is added to the active ingredient mixture prior to extrusion.

Description

"IMPROVED PROCESS TO OBTAIN COMPOSITIONS IN FORM OF EXTRUDED GRANULES AND METHOD TO REDUCE TEMPERATURE OF EXTRUSION OF COMPOSITIONS AGRICULTURAL AND GRANULES SO OBTAINED " This invention relates to formulations of agricultural chemicals, minerals and other substances. It relates in particular to the methods of preparation of granules capable of dispersing in water, containing such substances. The present invention provides an improved method of forming granules containing agricultural chemicals. Agricultural chemicals are formulated in various forms, for example, as large granules (nuggets) for direct application to the soil, grass or crops, emulsifiable concentrates, liquid fluid concentrates and water-miscible powders, which are normally diluted in water for application. Fluid liquids and water-miscible powders comprise most of the agricultural chemical formulations sold worldwide. The first ones are the aqueous suspensions and, although they generally present a satisfactory performance, they can be decanted during storage, requiring a vigorous agitation to resuspend. Due to the high water content (generally around 50%), the costs of packaging and transportation increase. Mixable powders with water are usually produced by mixing first the technical grade chemical, with surfactants (dispersing and wetting agents), fillers and possibly other ingredients. Then, the mixture is passed through an air mill or other suitable grinding device to reduce the size of the additives, as well as to produce an intimate mixture of the components. The resulting powder mixable with water is generally very bulky and is transported through the air rapidly. This can be dangerous for the user in the case of irritating or toxic materials. Water-dispersible granules (also known as dry fluids) that contain agricultural chemicals are designed to rapidly disperse in water and remain in suspension, for example, act as fluid fluids and as water-mixable powders, when prepare for the application in "spray" to the earth or plants. A desirable aspect of dry fluid materials is their applicability to solid chemicals of low water solubility. The common method of producing "dry fluids" is to convert the active agent into a powder formulation mixable with water, mixing and grinding the ingredients of the formulation. The resulting powder is converted into a granulate by agglomeration, using a granulator or similar device, and water, or water containing a binding agent. This is a fairly imperfect process and it is difficult to control the size of the granule. Mixing granules with water can also be obtained by mixing the desired ingredients of the granules in a form capable of to be extruded, extruded or mixed, and then, if required, the extruded product. Mechanical agitation may or may not be required or preferred to adjust the size of the granules. Extrusion methods practiced in the art can also include mixing with water before extrusion. U.S. Patent No. 5,443,764 provides a method for forming granules capable of dispersing in water. In this the desired ingredients of the granules are mixed in the presence of water, a wet mixture is formed that can be extruded, said mixture is extruded, and J-0 rolls the wet extrusions until they break, forming granules.

The granules, optionally, are dried. The inventor of the present discovered that, especially for the active ingredients of low solubility in water (for example, less than about 10 grams per liter of water, or 1%), it can be done with the extrusion process being surprisingly more efficient, without reducing the biological effect of the active ingredient, if an organosiliconated surfactant is added in minor amounts to the mixture of the active ingredient, before extrusion. The present invention also provides an extrusion process and 2o extruded extrusion-molded compositions containing crystalline materials (e.g., active and / or inert ingredients), having a glass transition temperature (Tg) of less than about 65 ° C, alternatively, less than approximately 75 ° C. Decreasing the operating temperature of the extrusion process, the present invention makes possible the most efficient extrusion of materials, such as active and / or inert ingredients having a glass transition temperature (Tg) of less than about 65 ° C, alternatively less than 75 ° C, while maintaining the crystalline structure of the active and / or inert material. Previously, the extrusion of said active and / or inert materials at higher temperatures produced amorphous solids that impaired the ability of the extruded product to disperse in water. Accordingly, the present invention provides improved extruded products, capable of dispersing in water. The organosilicone of the present invention is preferably solubilized in the water used to create the pasty consistency required for the extrusion, opposing its addition to the pre-mix powder directly. The ingredients of the extrusion-capable composition of the present invention will generally have one or more active chemical components, which may be liquid or solid at room temperature, and of a soluble or insoluble type in water. Typically, the active chemical component comprises from 1 to 99%, preferably from 20 to 95% by weight of the dry weight of the composition; more preferably about 50% to 80% by weight of the dry weight of the composition. The process of the invention can be carried out using a wide range of active ingredients. Examples of active ingredients include chemicals agr co as, as pes c as, er c as, ung c as, nsect c as and fertilizers; pigments; coloring matter; pharmaceutical compounds and minor elements. One or more examples of herbicidal active ingredients can be selected from: 2,2-dioxides of benzo-2, 1,3-thiadiazin-4-one, such as betazone; hormonal herbicides, such as MCPA, dichlorprop, MCPB and mecoprop; 3- [4- (4-halofenoxy) phenyl] -l, l-dialkylureas, such as chloroxuron; dinitrophenols and their derivatives, for example, DNOC, donoterb and dinoseb; dinitroanililine herbicides, such as dinitramine, nitraline and trifluralin; phenylurea herbicides such as diurone and fluometurone; phenylcarbamoylphenylcarbamates such as fenmedifam and desmedipham; 2-phenylpyridazin-3 -ones, such as pyrazone, uracil herbicides, such as lenacil, bromacil and terbacillus; triazene herbicides such as atrazine, simazine and azeproptrin; 1-alkoxy-2-alkyl-3-phenylurea herbicides such as linurone, monolinuron and chlorobromuron; pyridine herbicides such as clopyralid and picloram; 1, 2, 4-triazine-5-one herbicides such as metamitrone and metribuzin; benzoic acid herbicides such as 2,3,6-TBA, dicamba and chloramben; annuidate herbicides such as balachlor, alachlor, propachlor and propanil; dihalobenzonitrile herbicides such as dichlobenil, bromoxynil and ioxynil; haloalkanoic herbicides such as dalapon and TCA; diphenyl ether herbicides such as comoflorodifen and bifenox; N- (heteroarylaminocarbonyl) benzenesulfonamides such as DPX 4189; aryloxyphenoxypropionate herbicides such as fluzifop and diclofop; cydohexane-1 -3-d -one derivatives such as alkoxydim-sodium and tra cox m; er c as e pr o ta is like paraquat and quat; organoarsenic herbicides such as MSMA; amino acid herbicides such as glyphosate; and other herbicides such as dipenamid and naptalam.

Preferred herbicides include diuron, atrazine, simazine, cyanazine, oryzalin, fluometuron, metazole, methoxuron and hexazinone.

Examples of fungicides include imazalil, benomyl, carbendazim (BCM), methyl thiophanate, captafol, folpet, captan, sulfur, carbamates, dithiocarbamates, phenyl tin compounds, carbatins, dicarboximides (including iprodione, vinclozolin, procymidone), copper oxachloride, tpforin, dodemorf, tridemorph, dithianon, pyrazophos, binapacril, quinomethionate, panoctin, furalaxyl, tris (ethylphosphonate) aluminum, cymoxanil, etirimol, dimethirimol, fenarimol, fenpropidin, fenpropimorf, propiconazole, bupirimate, matalaxyl, ofurace, benalaxyl, oxadixyl, chlorothalonil, metaxanine, triazole derivatives such as triadimefon, triadimenol, diclobutrazol, flutriafol and penconazole and fungicides inhibitors of ergosterol synthesis. Preferred fungicides that are used as active ingredients include captan, tiram, macozeb, diclofluanid, metiram and vinclozolin.

Examples of insecticides that are used as active ingredients include pyrethroids such as organophosphorus insecticides, cypermethrin, pirimor, croneton, dimethoate, metasistox and formetion.

Examples of pigments include any of the wide variety of powder pigments or mixtures thereof. Suitable pigments of various kinds can be chosen, including: organic pigments from annequine, azoprene, azo, oxazne, coane to ene-ra-caroxic, perylenetetracarboxylic acid, polycyclic, quinacridone, and the thioindigo series, whose specific examples can be found in the "Color Index, 2a edic "; and inorganic pigments such as the colored pigments of the group of alkaline earth metals, antimony, cadmium, chromium, copper, iron, lead, ultramarine and zinc (Kirk-Ohtmer, Encyclopedia of Chemical Technology 15, 496-516 (1968)), pigments targets such as titanium dioxide, zinc oxide, white zinc lithophone (Kirk-Ohtmer, Encyclopedia of Chemical Technology 15, 517-541 (1968)); copper phthalocyanine pigments such as those mentioned in "Color Index, 2nd edition" as Blue Pigment; and black coal. Examples of coloring matter include anthraquinone dyes, azo dyes, methine dyes and naphthoquinone dyes. In addition to the active ingredient component, the ingredients will include at least one organosiliconated surfactant component and may contain other surfactants, and optionally other components such as a filler component to provide the desired content of the active ingredient and / or a binding agent and / or a dispersant, such as, for example, lignosulfonate, formaldehyde naphthalene condensate, kraft lignosulfonate, and EO / PO block copolymer (ethylene oxide / propylene oxide) (such as Pluronic ™ and Plurafac ™ surfactants from BASF). The organosiliconated surfactant component of the present invention is preferably a silicone-glycol copolymer, which is non-ionic, has a number of HLB (Hydrophilic / Lipophilic Balance) in the range of about 5-13, alternatively, an HLB of 5-1 1 or preferably an HLB of 5-8, reduces the surface tension of the composition and is not toxic to the plants that will be treated. The organosiliconized surfactant of the present invention is used in an amount of between 0.001 and 0.4%, alternatively, in an amount of 0.001 to 0.01%, by weight of the dry weight of the pre-extruded composition. The present inventor has discovered that more than this amount of organosiliconized surfactant will no longer be effective in reducing the surface tension of the pre-extruded mixture and, in fact, or will detrimentally affect the extrusion process, and will make it more difficult and less economical. the production of the dry granule. The method of the present invention, which includes the addition of an organosiliconated surfactant in the pre-extrusion mixture of an agricultural product that is capable of being subjected to extrusion, allows the reduction in the amount necessary for this process, which surprisingly leads to , to the economy of energy and material in the manufacture of the agricultural granules described here. In addition, the present invention provides an improved extrusion process as less abrasion occurs on the surface of the extrusion mold, as evidenced by a reduction in or the surface temperature. Moreover, due to the lower need for water in the extrusion process, the active component of the compositions according to the present invention is not subjected to the increased temperatures for long periods, which are required to remove the excess water in the traditional extrusion processes. Additionally, the improved process of of the agricultural products, because only a very small amount of organosiliconated surfactant is added. Examples of organosiliconized surfactants useful in the present invention include, for example, non-ionic silicone-glycol copolymers, such as those marketed by SILWET (Witco OSi Speciaties Group, One American Lane, Greenwich, CT), including SIL WET L-77 (modified polysiloxane dimethyl polyalkylene silicone oxide) (CAS: 27306-78-1), SILWET L -7210, L-7220, and L-7230 (CAS: 68937-55-3), and as described in "Adjuvants for Agrichemicals, Ed Foy, CRC Press (1992)", and non-ionic silicone polyethers such as those marketed by Dow Corning (Midland, MI), such as Sylgard 309 (aceto of 2- (3-hydroxypropyl) -heptamethyltrisiloxane, ethoxylated), and their mixtures, provided that the mixture or the individual components are not phytotoxic. A measure of phytotoxicity includes the aqueous dilution of a given pesticide, the more concentrated spray application allowed by the recommendations on the EPA registered label of the product, and the application of this dilution to the surface of the target crop in the amount Highest recommended pounds of active / unit area. The culture is observed for 21 days, noting any discoloration or physiological changes that are detrimental to the development of the crop. In one embodiment of the present invention, the only surfactant present in the extruded or extrudable composition is an organosiliconated surfactant, such as those described herein. &? rr The agreement is with, or is in, con figuration, not with additional surfactants. It only has the organosiliconized surfactants described here. Examples of additional surfactants of the anionic type that can be used additionally to the organosiliconized surfactants of the present invention include soaps, salts of aliphatic monoesters or sulfuric acid such as sodium lauryl sulfate, salts of sulfonated aromatic compounds, for example sodium dodecylbenzenesulfonate. , sodium lignosulfonate, calcium or ammonium or butylnaphthalene sulfonate, and a mixture of the sodium salts of the diisopropyl- and triisopropyl-naphthalene sulfonates. Suitable agents of the non-ionic type include, for example, the condensation products of ethylene oxide with fatty alcohols, such as oleyl alcohol or cetyl alcohol, or with alkyl phenols such as octyl phenol, nonyl phenol and octyl cresol. Other non-ionic agents are the partial esters with ethylene oxide and the lecithins and phosphoxylated surfactants, such as the block copolymer of phosphorylated ethylene oxide / propylene oxide and ethoxylated and phosphorylated substituted styryl phenol. The additional surfactants and dispersants included are those marketed by International Specialty Products (ISP) Europe (Research Park, Guildford, UK), Ine, such as the Agrimer® VEMA ES polymers (which are described by the manufacturer as low weight copolymers). molecular, partially neutralized, butyl maleate of vinyl methyl ether and ethyl maleate of vinyl methyl ether). The composition of the present invention may contain at least , naphthalene, phosphate, sulfosuccinates and non-ionic esters, such as tridecyl alcohol ethoxylate; and / or at least one dispersing agent, such as those selected from the group of condensates of naphthalene, lignosulfonates (such as sodium lignosulfonate), polyacrylates and phosphate esters. A variety of fillers can be used in granule compositions that are dispersed in water. Examples of fillers include: mineral lands and clays such as, for example, kaolin, hydrated aluminum silicate kaolin, bentonite, kieselguhr, Fuller's earth, Attaclay, diatomaceous earth, variety of fine clay soil, loess, talc, chalk, dolomite, limestone, lime, calcium carbonate, magnesium powder, magnesium oxide, magnesium sulfate, sodium chloride, gypsum, calcium sulfate, pyrophyllite, silicic acid, silicates and silica gels; fertilizers such as, for example, ammonium sulfate, ammonium phosphate, ammonium nitrate and urea; natural products of vegetable origin such as, for example, ground grains and flours, ground crust, ground wood, ground walnut shells and cellulose powders; and synthetic polymeric materials such as, for example, pulverized or ground plastics and resins. When used, the filler components typically comprise from 1 to 99% and preferably from 5 to 80%? by weight, more preferably, 10 to 40%), and the most preferred range of 20 to 35% > of the total granulated composition. However, in one configuration, the granular composition can be formed essentially from one component of the po re eno mo mo, p organosiliconado, a vehicle, such as ammonium sulfate, a dispersant, water and the active component. The present invention preferably concerns the wet mixture of the ingredients described herein and the extrusion of the wet mixture, which has a consistency similar to a paste at the extrusion point, ie, a consistency analogous to the thick paste produced in the process of bread making Such pulp-like consistency is obtained by the total or kneaded mixture, using a mezcal apparatus such as a flat, double-shaft auger mill, or an extrusion equipment can be adapted to provide the proper mixture. The aqueous dilution of the organosiliconated surfactant is preferably presented in the mixing step of the process, in a controlled quantity, so that it is sufficient to mobilize the surfactant component and enables the formation of the granules from the mixture, by extrusion, but which is insufficient to cause the granules, once formed, to stick and agglomerate Although the amount of water used in a given formulation will be variable, it will generally be in the range of 5 to 50 liters (preferably 10 to 30 liters, more preferably 20 liters) of water per 100 kg of dry mix. The order of addition and mixing of the granule ingredients is not narrowly critical. In one configuration, for example, the dry ingredients are combined and the composition is mixed, then, while adding water. You can add water, for example, as a non-spray, and in a con guration, one of the surfactants is added as an aqueous solution, to a dry mixture of other components. The use of the wet mixing process described above also has the advantage of allowing the use of solid surfactants of a technical grade, without the need to grind to fine powder said surfactants. The materials used in the process of the invention must be presented in a finely divided form, preferably in the form generated by the airmills, which is generally the form of the technical grade chemicals provided by the manufacturers. After total mixing, the composition of the present invention is subjected to extrusion through suitable holes. The size of the granules will depend on the size of the holes and the extruder can thus be adjusted with a mesh or mold selected to provide the desired granule size. The extrusions can vary considerably in length, for example, up to 2.5 cm or more in length. A common knowledge technician will appreciate that the shape of the extrudate is determined by the mold. This is typically 2 mm or less, more typically 1 mm. The length of the dough is typically 20 mm or less, more typically 3 to 8 mm long, in the present exemplified method. After extrusion of the wet mix, the wet extrusions are dried by unloading them into a continuous fluid bed dryer, and dried to a moisture content that is in the range of l-5% > , preferably about 3%. The fluid bed dryer used in this configuration of the present invention preferably provides mechanical agitation to break the extruded products into individual granules of approximately the desired size. The dry granules are discharged in a mesh where the granules that exceed the desired size of the fines are separated, so that they are recycled in the mill. Preferably, at least 95% by weight of the composition will comprise granules of a size that allows them to pass through a 8 US mesh (2.36 mm) screen, but are retained in a 300 micron sieve. In many cases it is possible to obtain more than 99% of the particles in that range of dimensions. The invention is now illustrated, but in no way is it limited to the following example. EXAMPLE The following dry ingredients are weighed in a powder mixer or other closed mixer with a suitable closure cap, and are mixed: 521 g of Vinclozolin 96% w / w (BASF AG), 50 g of ammonium sulfate (BASF AG ), 50 g of sodium lignosulfonate (Borregard AS, Sparsborg, NORWAY), 349 g of hydrated aluminum silicate kaolin (Blancs Mineraux de Paris) and a mixture of SIL WET L-77 and SILWETT L-7230. A 1: 1 mixture of the two surfactants is added to the water at a dilution percentage of 0.1% in water and then 22 grams of this solution is mixed with 78 grams of a pre-mix of pesticide powder (described above) for less of 90 seconds in a high-speed mixer and cut, for Make a paste that will be subjected to extrusion, which is poured directly from the mixer to the extruder. Alternatively, the paste is made by mixing the pre-mix powder with the surfactant solution in a continuous kneader (retention time of less than 20 minutes) or in a batch mixer / blender, mixing for less than 20 minutes or in a continuous kneader / extruder system (for example, Teledyne Readco or Bepex Extrudomixer). The mixture is subjected to extrusion through a molding surface with openings of 1, 5 mm in diameter, in a regime close to the maximum load of the machine. This results in deep mixing of the ingredients, formation of a paste and extrusion through the mold or mesh. The extrusions thus formed were dumped in a continuous or batch dryer to produce granules with residual moisture content of about 3% by weight. The previous mixture that was made without the organosiliconadoo surfactant, was made in an extrusion-friendly composition containing 77% dry pre-mix powder and 23% water, and extruded at approximately 800 lb / hr through a 1.5 mm mold. The friction on the surface of the mold raised the temperature to 65 ° C and eventually contributed to the mold failure after 20,000 lbs were extruded. of the product. A similar composition including the organosiliconized surfactant of the present invention required only 20% or moisture and a temperature of 25 ° C on the surface of the mold, limiting the tension in the equipment / mold and product. It is expected that amounts will be used reduced solvent / water (15-20%) if higher temperatures are tolerated. An unexpected advantage of the process of the present invention is the ability to dilute the product in hard water (mineral content greater than 1000 ppm) without affecting the performance of the final product. In addition, because extrusion with lower water content was made possible by the present invention, less energy is required to dry the final product, which leads to saving time and energy. Another unexpected advantage discovered was the decrease in the temperatures on the surface of the mold. All references cited here are incorporated by reference.

Claims (6)

1. : 1.- An improved process for the preparation of compositions in the form of extruded granules, which contain at least one active ingredient, characterized in that it comprises the addition of at least one organosiliconated surfactant to the composition, before extrusion.
2. 2. - An improved process according to claim 1, characterized in that said organosiliconated surfactant is added in an amount ranging in the range of 0.001 to 0.1% by weight of the composition before extrusion.
3. 3. An improved process according to claim 1 and 2, characterized in that said organosiliconized surfactant is a copolymer of silicone and glycol.
4. 4. An improved process according to claim 3, characterized in that said organosiliconized surfactant has a HLB number in the range of 5-1 1.
5. 5. An improved process according to claim 1 to 4, characterized in that said granules do not contain other surfactants than said organosiliconated surfactants.
6. 6. An improved process according to claim 1 to 5, characterized in that said active ingredient is an agricultural chemical compound. 1. An improved process according to claim 6, characterized in that said active ingredient is a herbicide. 8. An improved process according to claim 6, characterized in that said active ingredient is a fungicide. 9. An improved process according to claim 6, characterized in that said active ingredient is an insecticide. 10. A method of reducing the extrusion temperature of exempt agricultural compositions, according to claim 1, characterized in that it comprises the mixture of an organosiliconized surfactant with an initial composition, before extrusion. The method according to claim 10, characterized in that said initial composition comprises water and said method also comprises the addition of said organosilicone to said water before said mixing. 12. Extruded granules obtained with the process of claim 1, comprising at least one active ingredient and at least one organosiliconized surfactant in an amount that is in the range of 0.001 to 0.1%, by weight of the composition, before the extrusion. R E, S U M E N This is an improved process for obtaining extrusion granules, which contain an active ingredient, characterized in that it comprises the addition of at least one organosiliconated surfactant to the composition, before extrusion. A method for reducing the extrusion temperature of granular agricultural compositions and the resulting granules is also proposed.