TWI643556B - Agrochemical formulation, a method for its preparation and the use thereof - Google Patents

Abstract

The present invention provides a composition comprising a microencapsulated clomazone which is contained in a microcapsule having a microcapsule wall formed by agglomeration of a plurality of amphoteric polymer electrolytes. In particular, the microcapsule wall is formed from cellulose derivatives such as carboxymethylcellulose, natural gums such as acacia and gelatin. The microcapsule wall preferably comprises a crosslinking agent, in particular, a glycoluril resin. The invention also provides a method of extruding by encapsulation by coacervation.

Description

Agricultural chemical formulation, preparation method thereof and use thereof

The present invention relates to agrochemical formulations, in particular to formulations comprising microencapsulated active ingredients, and in particular to formulations comprising microencapsulated clomazone. The invention further relates to a process for the preparation of such a formulation and to its use.

A variety of different methods are known for blending agrochemical products. One method used is microencapsulation of one or more active ingredients, wherein the active ingredients are embedded in microcapsules formed from polymer walls. Such capsules may be further formulated, for example, by suspending the microcapsules in a suitable carrier liquid for application to the locus to be treated.

One such active ingredient known to be formulated in such a manner is destructible. Can be eliminated, (2-[(2-chlorophenyl)methyl]-4,4-dimethyl-3-iso Oxazolone is a well known for controlling soybeans, cotton, cassava, corn, rapeseed, sugar cane, tobacco and other crops. Traceable for such plants as barnyard grass, green foxtail, crabgrass, Solanum nigrum, Elsholtzia water spine needle, Thlaspi arvense, willow Hedgehog (willow thorn smartweed), cocklebur, pigweed, wild watermelon seedling, wolf grass and other annual grasses and broadleaf weeds, perennial spines The growth of (Cephalanoplos), Daji, horsetail, and Sonchus Caideng has a strong inhibitory effect.

Currently, commercially available traceable formulations are an emulsion (EC) with many disadvantages. First, the formulation contains a large amount of an organic solvent such as toluene or xylene. The application of such solvents to the plant to be treated is a waste material and is harmful to the environment. Second, the extinction has a relatively high vapor pressure, resulting in the need for high application rates to achieve effective plant control, which in turn leads to higher costs. Third, because of its high vapor pressure, the extinction can easily drift from the application site, causing damage to crops or other plants in adjacent areas. In particular, drifting traceable droplets or vapors are phytotoxic to sensitive plants. Avoiding this drift requires very careful and precise spraying techniques that are difficult to apply. For example, spraying must apply low pressure, use large amounts of water, be limited to low wind conditions, be limited to the direction of a particular prevailing wind, and repeat, such as twice a day. In particular, sensitive crops, such as trees and vegetables, cannot be sprayed in the air.

Microencapsulation that can be eliminated can be used to treat and overcome the shortcomings of the aforementioned EC formulations. As is known, this microencapsulation is known in the art.

For example, CN 1491540 is a method for making microencapsulated herbicidal herbicide compositions by application of interface polymerization. The microcapsules are formed from a polyethylene outer shell to reduce the volatilization of the extinction. However, this preparation method is very complicated and the reaction time is very long. In addition, once applied, the resulting microcapsule outer wall material degrades slowly and has high renewal.

Microencapsulation of agrochemically active components, in particular microencapsulation and formulation, can be described in EP 1 840 145. The microencapsulation process disclosed in EP 1 840 145 comprises forming a monomer comprising a lipid isocyanate (for example tetramethyl-m-xylylene diisocyanate (TMXDI)), an aromatic isocyanate prepolymer (for example multi-methylene Base polyphenyl isocyanate (PAPI), an acetylene urea monomer (eg tetrabutoxymethyl acetylene urea), an active ingredient, one or more solvents and other components (eg antioxidants and analogues thereof) phase. This oil phase is dispersed in the aqueous phase to form an emulsion. The aqueous phase comprises water with one or more surfactants, one or more water soluble polymers such as polyvinylpyrrolidone, one or more gums and the like. The polymerization of the isocyanate and acetylene urea components is initiated by heating the dispersion, thereby forming a polymer shell at the interface between the dispersed organic phase and the aqueous phase.

An improved formulation for microencapsulated compounds (e.g., extrinsic) has been discovered.

In particular, it has been found that the extrudate can be encapsulated in microcapsules having an outer wall formed by an amphoteric polymer electrolyte, and more particularly, by coacervation. In a preferred embodiment, the microcapsules are formed by the coacervation of a cellulose derivative (e.g., sodium carboxymethylcellulose), a natural gum (e.g., gum arabic), and gelatin. The microcapsules can be further formulated in a known manner, for example as a suspension in water for subsequent application and use.

Accordingly, in a first aspect, the present invention provides a traceable composition comprising microencapsulation, wherein the traceable system comprises microcapsules having microcapsule walls formed by coacervation of a plurality of amphoteric polymer electrolytes in.

In another aspect, the present invention provides a mimetic composition comprising microencapsulation, wherein the catastrophic system is contained in a microcapsule having a microcapsule wall formed of a cellulose derivative, natural gum and gelatin.

The compositions of the present invention comprise microcapsules having outer walls formed from very low toxicity and biodegradable materials. This composition has high stability and precise control of the release rate of the mimetic active ingredient. As a result, the likelihood of the active ingredient drifting away from the application site is reduced, resulting in a composition with low environmental impact. Overall, this composition is relatively inexpensive and simple to prepare.

As described in more detail below, the compositions of the present invention can be prepared by coacervation techniques.

The composition of the present invention includes a eliminable inclusion in the microcapsules. The extrudate may be present in the composition in an amount of from 0.5 to 25% by weight of the microcapsules, preferably from 1.0 to 20.0%, and more preferably from 1.5 to 15% by weight of the microcapsules.

The composition of the present invention comprises microcapsules having walls other than cellulose derivatives, natural gums and gelatin.

The cellulose derivative can be any suitable derivative of cellulose. Preferred derivatives are cellulose gums, especially carboxyalkyl celluloses. A particularly preferred cellulose gum is carboxymethyl cellulose. The cellulose derivative is preferably present as a salt, more preferably a metal, particularly a salt of a metal derived from Group I or Group II of the periodic table, with a Group I metal salt being particularly preferred. The sodium salt is particularly good. A particularly preferred cellulose gum for forming microcapsules is sodium carboxymethylcellulose.

Cellulose derivatives of microcapsules used to form the compositions are known in the art and are commercially available or can be prepared by known techniques.

The cellulose derivative may be present in the microcapsule wall in an amount of from 1 to 30% by weight, more preferably from 2.5 to 20% by weight. Particularly good is in the range of 2.5 to 17.5%.

The microcapsule wall further comprises a natural gum. Natural gums can be prepared from plant extraction or by microbial fermentation as is known in the art. Suitable natural gums are known to the art and are commercially available. The natural glue is optimally a polymer electrolyte. Preferred gums include gum arabic, gum ghatti, tragacanth and karaya gum. The special natural glue is gum arabic.

The natural gum may be present in the microcapsule wall in an amount of from 5 to 75% by weight, more preferably from 7.5 to 70% by weight, still more preferably from 10 to 65% by weight. Particularly preferred is an amount in the range of 10 to 60%.

The microcapsule wall of the present invention further includes gelatin. Gelatin is well known to the art and is commercially available.

The gelatin may be present in the microcapsule wall in an amount of from 5 to 90% by weight, more preferably from 10 to 90%, still more preferably from 12 to 85% by weight.

As discussed above, the microcapsules of the compositions of the present invention are formed from cellulose derivatives, natural gums, and gelatin. In order to increase the strength of the microcapsules, the material of the microcapsule wall may further include a crosslinking agent. A preferred crosslinking agent is a glycoluril resin.

The glycoluril resin can be produced by a condensation reaction of glycoluril and an aldehyde. Suitable aldehydes are known in the art and include, for example, formaldehyde, paraformaldehyde, acetaldehyde, butyraldehyde, paraldehyde, glyoxal, furfural, propionaldehyde, benzaldehyde, and mixtures thereof. A preferred embodiment of the invention is such A glycoluril resin prepared from a crosslinking agent of formaldehyde, acetaldehyde and butyraldehyde as microcapsule wall materials.

Examples of glycoluril resins suitable for use in the present invention include highly alkylated/alkoxylated, partially alkylated/alkoxylated, or mixed alkylated/alkoxylated glycoluril resins. More specifically, the glycoluril resin can be methylated, n-butylated or isobutylated.

Glycolour resins suitable for use in the alkoxylation of the present invention are known in the art, for example from US 2011/026903, and may be represented by the following formula (I): Wherein R ₁ , R ₂ , R ₃ and R ₄ each independently represent a hydrogen atom or an alkyl group. A preferred compound of formula (I), wherein R ₁ , R ₂ , R ₃ and R ₄ each independently represent an alkyl group, wherein the alkyl group has from 1 to 12 carbon atoms, more preferably from 1 to A compound having 8 carbon atoms, more preferably 1 to 6 carbon atoms, most preferably 1 to 4 carbon atoms. R ₁ , R ₂ , R ₃ and R ₄ may each represent the same or different alkyl groups. The alkyl group can be straight or branched.

Examples of specific commercially available glycoluril resins include CYMEL® 1170, 1171, and 1172. CYMEL® glycoluril resin is commercially available from CYTEC Industries.

The substantially fully mixed alkylated acetylene urea derivative and the substantially sufficient methoxylated acetylene urea derivative are a novel crosslinking agent, the starting material of which is acetylene urea, also known as acetylene diurea or Glycoluril. Acetylene urea is prepared by reacting dimon urea with one mole of glyoxal. The precise chemical name for acetylene urea is tetrahydroimidazole-(4,5-d)imidazole 2,5(1H,3H)-dione. Acetylene urea can be filled with methylol by reacting a molar acetylene urea with tetramol formaldehyde Chemical. The product produced was identified as tetramethylol acetylene urea. The tetramethylol acetylene urea can then be reacted with a selected amount of methanol to facilitate partial methylation of the fully methylolated acetylene urea, which can then be followed by a higher aliphatic monohydric alcohol, for example 2 to 4 One carbon atom is alkylated. The monohydric alcohol can be a primary or secondary alcohol. Examples of suitable higher monohydric aliphatic alcohols include ethanol, n-propanol, isopropanol, n-butanol, isobutanol, and the like. It may be advantageous to methylate tetramethylol acetylene urea in a sufficient amount, and then the desired amount of ethanol, propanol or butanol is incorporated into the acetylene urea derivative by using a transetherification reaction.

A sufficiently etherified, sufficiently methylolated acetylene urea derivative is generally not considered a resin material because, as an individual entity, it is a simple pure compound or a mixture of simple pure compounds. However, it is a latent resin-forming compound which reacts with a specific ionic water-dispersible, non-gel polymerizable substance when heated, more specifically when heated under acidic conditions.

The notion of the average degree of methylation or more extensive alkylation, and the concept of average degree of methylolation will be discussed below so that this concept can be fully understood.

In theory, acetylene urea can be completely methylolated, that is, tetramethylol acetylene urea can be produced. However, often, analysis of commercially available compositions that may be referred to as tetramethylol acetylene urea shows partial degrees of methylolation, i.e., an average degree of methylolation below 4.0. It is not accepted that partial methylolation of a particular molecule is considered to be possible. Therefore, when a composition exhibits a degree of methylolation of 3.70, 3.80 or 3.90 in analysis, it must be understood that it is the average degree of methylolation of the acetylene urea compound and represents the aforementioned methylol composition system. From a major amount of tetramethylol acetylene urea to a minor amount of trimethylol acetylene urea and such (perhaps) lower amounts (including micro-tracks) such as dimethylol acetylene urea and / or monomethylol Composed of derivatives of acetylene urea. The same concept of averaging also applies to the alkylation or etherification of tetramethylol acetylene urea compositions. Thus, when a particular composition analysis shows a degree of methylation, for example, on average, between about 0.9 and 3.60, and a higher alkylation has an average ethylation of between about 2.80 and 0.40, When the degree of propylation and / or butylation, it must be concluded that there is a majority of the mixture in this composition Ether of tetramethylol acetylene urea. For example, the composition may contain monomethyl ether of tetramethylol acetylene urea, triethyl ether; dimethyl ether of tetramethylol acetylene urea, diethyl ether; or top three of tetramethylol acetylene urea Ether or monoethyl ether. There may also be traces of tetramethyl ether of tetramethylol acetylene urea. It may also be present as methyl ether of various tetramethylol acetylene ureas, monoethyl ether, diethyl ether and triethyl ether of various tetramethylol acetylene ureas, monopropyl ether, dipropyl ether and three Propyl ether, as well as monobutyl ether, dibutyl ether and tributyl ether. It is possible to produce monomethyl ether, monoethyl ether, monopropyl ether, monobutyl ether of tetramethylol acetylene urea, which can be classified as a tetra-mixed-alkylated derivative. However, it is generally preferred to use a higher monohydric alcohol having 2 to 4 carbon atoms to produce a mixed total ether of tetramethylol acetylene urea from methyl alcohol. Therefore, a double mixed-methylated product is preferred. However, it is also possible to use tri-mixed-alkylated derivatives as well as tetra-mixed-alkylated derivatives.

The crosslinking agent may be present in the microcapsule wall in an amount of from 5 to 90% by weight, more preferably from 10 to 90% by weight, still more preferably from 12 to 85% by weight.

In the material of the microcapsule wall, the weight ratio of the cellulose derivative to the natural gum is preferably in the range of from 0.075 to 0.75, more preferably from 0.1 to 0.65. The weight ratio of the cellulose derivative to gelatin is preferably from 0.075 to 0.6, and more preferably from 0.08 to 0.5. The weight ratio of the cellulose derivative to the crosslinking agent is preferably from 0.075 to 0.6, and more preferably from 0.08 to 0.5. The weight ratio of natural gum to gelatin is preferably in the range of 0.25 to 3.0, more preferably 0.3 to 2.0. The weight ratio of the natural gum to the crosslinking agent is preferably in the range of 0.25 to 3.0, more preferably 0.3 to 2.0. The weight ratio of gelatin to crosslinker is preferably in the range of from 0.3 to 3.0, more preferably from 0.4 to 2.5.

In one embodiment, the microcapsule wall system comprises a cellulose derivative in a weight ratio of 1:4:5:5, natural gum, gelatin, and a crosslinking agent. In a further embodiment, the wall material of the microcapsules comprises a cellulose derivative, natural gum, gelatin and crosslinker in a weight ratio of 0.4:1.6:2:2.

The microcapsules of the composition contain a mimetic as an active ingredient. Destroyable in microcapsules The proportion of traces is preferably from 5% to 85%, more preferably from 7.5 to 80%, still more preferably from 9 to 75% by weight.

The compositions of the present invention may include one or more emulsifiers, in particular, to aid in the formation of an emulsion when the composition is added to the spray tank prior to application to the site to be treated. The emulsifier may be cationic, anionic or nonionic, but more preferably anionic or nonionic. An example of a particularly suitable anionic surfactant for this purpose is a sulfonate such as calcium dodecylbenzenesulfonate. Examples of particularly suitable nonionic surfactants are polyoxyethylated (POE) sorbitan esters such as POE (20) sorbitan trioleate and polyoxyethylated (POE) sorbitol esters, for example POE (40) sorbitol hexaoleate. Suitable emulsifiers are known to the art and are commercially available. For example, POE (20) sorbitan trioleate is commercially available under the trade name TWEEN 85 sold by Uniqema. POE (40) sorbitol hexaoleate is commercially available under the trade names ATLAS G1086 and CIRRASOL G1086 sold by Uniqema.

The combination of POE sorbitan ester and POE sorbitol ester optimizes the HLB (hydrophilic-lipophilic balance) value of the surfactant to provide the highest quality emulsion (minimum hanging drop) when the composition is added to water. High quality emulsions typically produce optimum herbicidal properties. Thus, with regard to preferred herbicidal properties, particular note is the composition of the invention comprising one or more nonionic surfactants selected from the group consisting of polyoxyethylated (POE) sorbitan esters, such as POE (20). And sorbitan trioleate, and polyoxyethylated (POE) sorbitan esters, such as POE (40) sorbitol hexaoleate, and mixtures thereof.

The composition of the present invention comprises microcapsules containing traceable molecules. The extrudate is preferably present in the microcapsules in combination with a liquid carrier, particularly a dissolvable solution dissolved in a liquid carrier. Any suitable liquid carrier can be used. The liquid carrier of the composition of the present invention preferably comprises one or more lines of fatty acid esters of alkanols, more preferably one or more C ₁ to C ₄ fatty acid ester of the alkanol. The fatty acid ester is preferably present in the liquid carrier in an amount from about 40 to about 99.8% by weight of the carrier.

The fatty acid moiety of the fatty acid ester consists of a carboxylic acid group bonded to a hydrocarbon. Preferred sources of fatty acids are natural sources such as seed oil. Fatty acids can be non-branched or branched. But typically the natural source is non-branched. The hydrocarbon linkage may be saturated or unsaturated; preferably the hydrocarbon linkage is saturated, i.e., alkyl, or contains 1 or 2 carbon-carbon double bonds, i.e., alkenyl linkage. A fatty acid ester formed from a fatty acid having an odd number of carbon atoms, that is, an even number of carbon atoms in the hydrocarbon group, can be used in the composition of the present invention, and a fatty acid ester formed from a fatty acid having an even number of carbon atoms, that is, It has an odd number of carbon atoms on the hydrocarbon linkage. However, fatty acids derived from natural sources typically contain an even number of carbon atoms, and therefore esters containing fatty acids having an even number of carbon atoms are preferred for reasons of availability and cost on the market. Fatty acid compositions derived from natural sources, such as seed oil, typically consist of fatty acids having a range of lengths and different degrees of unsaturation. The fatty acid ester composition derived from such a fatty acid mixture can generally be used in the composition of the present invention without first separating the fatty acid ester.

Fatty acids from natural sources contain at least 4 carbon atoms and are generally limited to 22 carbon atoms. Although esters of lower fatty acids, i.e., containing as little as 4 carbon atoms, can be used in the compositions of the present invention, esters having at least 8, more preferably at least 10 carbon atoms, are preferred because Advantageous physical properties such as its low volatility. Esters of lower fatty acids can be mixed with higher fat esters to reduce polarity, water solubility and volatility. Since fatty acids derived from natural sources typically contain from 8 to 22 carbon atoms, more typically from 10 to 22 carbon atoms, esters of these fatty acids are preferred for reasons of availability and cost on the market. C ₁₀ to C ₂₂ fatty acid esters having an even number of carbon atoms are, for example, sinapic acid, lauric acid, palmitic acid, stearic acid, oleic acid, linoleic acid, and linoleic acid. Preferably, the one or more fatty acid esters in the composition of the present invention comprise at least about 80%, more preferably at least 90% by weight, containing from 8 to 22 carbon atoms, preferably from 12 to 20 carbon atoms. And more preferably a fatty acid ester of 16 to 18 carbon atoms.

Fatty acid compositions derived from natural sources, such as seed oil, typically consist of fatty acids having a range of lengths and different degrees of unsaturation. The fatty acid ester composition derived from such a fatty acid mixture can be used in the composition of the present invention without first separating the fatty acid ester. Suitable fatty acid esters derived from plants include sunflower, rapeseed, olive, corn, large Seed and fruit oils of beans, cotton and linseed. In a preferred embodiment of the composition of the present invention, the one or more fatty acid esters comprise fatty acid methyl esters derived from seed oil of sunflower, soybean, cotton or linseed. A particularly preferred embodiment is one in which one or more fatty acid esters comprise a fatty acid methyl ester derived from soybean oil (also known as methylated soybean oil or soy fatty acid methyl ester).

Fatty acid esters of alkanols and methods for their preparation are well known in the art. For example, "biodiesel" typically includes ethanol or a more common fatty acid ester of methanol. Two main routes for the preparation of fatty acid alkanol esters: transesterification starting with additional fatty acid esters (usually naturally occurring esters with glycerol), and direct esterification starting with such fatty acids. There are various methods known for these two paths. For example, direct esterification can be carried out by contacting a fatty acid with an alkanol in the presence of a strong acid catalyst such as sulfuric acid. The transesterification can be carried out by contacting the starting fatty acid ester with an alcohol in the presence of a strong acid catalyst such as sulfuric acid, or a more common strong base such as sodium hydroxide.

The alkylated seed oil is a transesterification product of seed oil and alkanol. For example, methylated soybean oil, also known as soy fatty acid methyl ester, includes a methyl ester produced by the transesterification of soybean oil with methanol. Soy fatty acid methyl esters thus include methyl esters of fatty acids, which are about the molar ratio at which fatty acids occur when esterified with glycerol in soybean seed oil. The alkylated seed oil, such as soy fatty acid methyl ester, can be distilled to adjust the ratio of methyl fatty acid esters.

As is known, the liquid carrier is present in the microcapsules together with the extrudate. The ratio of the extrudate to the liquid carrier can be from 0.005 to 0.4, more preferably from 0.0075 to 0.3, still more preferably from 0.01 to 0.25.

The compositions of the present invention may further comprise one or more stabilizers. Suitable stabilizers are known to the art and are commercially available. Lignosulfonates are particularly preferred stabilizers for inclusion in the compositions of the present invention.

It has been unexpectedly discovered that lignosulfonates greatly increase the stability of microcapsules containing a mixture of fatty acid alkanol esters in the compositions of the present invention. One or more woods in the composition of the invention The amount of the sulfonate may range from about 0.1 to about 20% by weight of the composition, but in terms of cost, the amount is preferably no more than about 10%, more preferably no more than about 8%. More preferably, it does not exceed a weight ratio of about 6% and optimally no more than about 5% of the composition. Preferably, the one or more lignosulfonates total at least about 0.5% by weight of the composition, although amounts up to about 0.1% can be used. More preferably, the one or more lignosulfonates total at least about 1% by weight of the composition and most preferably at least about 2% by weight of the composition. The amount of lignosulfonate required to provide the desired degree of stability depends on the other components of the composition and can be determined by simple experimentation.

Lignin, the basic building block of lignosulfonate, is formed in woody plants and is a complex natural polymer in terms of structure and homogeneity. Lignosulfonates are sulfonated plant lignin and are well known by-products of the paper industry. The lignosulfonate used in the composition of the present invention may be subjected to a sulfite pulping process or a kraft pulping (also known as kraft pulping) process, including subsequent sulfonation, by basic Chemical modification of lignin components to prepare. These pulping processes are well known in the paper industry. The sulfite pulping process and the Kraft pulping process are described in Lignotech (for example, 'Specialty Chemicals for Pesticide Formulations', October 1998) and MeadWestvaco Corp (for example, "From the Forests to the Fields", 1998 6 (monthly) in the published literature. The crude lignosulfonate preparation typically contains, in addition to the sulfonated lignin, other plant-derived chemicals such as sugars, sugar acids and resins, and inorganic chemicals. While such coarse lignosulfonate preparations can be used in the compositions of the present invention, it is preferred that the crude preparation be first refined to provide a higher purity lignosulfonate. Lignosulfonates in the context of the present disclosure and the scope of the patent application also include lignosulfonates which have been extensively chemically modified. An example of a widely chemically modified lignosulfonate is oxylignin, wherein the lignin is reduced in number by reducing the number of sulfonic acids and methoxy groups and increasing the number of phenol and carboxylic acid groups. The row method is oxidized. An example of an oxylignin is VANISPERS E A sold by Borregaard LignoTech.

Lignosulfonates are versatile depending on the degree of cation, degree of sulfonation and average molecular weight. The lignosulfonate used in the composition of the present invention may contain sodium, calcium, magnesium, zinc, potassium or ammonium The cation or mixture thereof, but preferably contains sodium. The degree of sulfonation is defined as the number of sulfonic acid groups per 1000 units of molecular weight of lignosulfonate, and typically ranges from about 0.5 to about 4.7 in commercial products. The lignosulfonate salt in the composition of the present invention preferably contains a degree of sulfonation ranging from about 0.5 to about 3.0. Lignosulfonates containing a degree of sulfonation ranging from about 0.5 to about 3.0 can be prepared by controlling sulfonation in a Kraft pulping process. For example, the degree of sulfonation using the Kraft pulping method is 2.9 for the commercially available product REAX 88A, 0.8 for the REAX 85A, and 1.2 for the REAX 907. The molecular weight of commercially available lignosulfonates typically ranges from about 2,000 to about 15,100. The lignosulfonate used in the composition of the present invention preferably has an average molecular weight of about 2,900 or more.

Examples of commercially available refined lignosulfonate products useful in the compositions of the present invention include, but are not limited to, REAX 88A (sodium of chemically modified low molecular weight Kraft lignin polymer solubilized by five sulfonic acid groups) Salt, sold by MeadWestvaco), REAX 85A (sodium salt of chemically modified high molecular weight Kraft lignin polymer, sold by MeadWestvaco), REAX 907 (sodium of chemically modified high molecular weight Kraft lignin polymer) Salt, sold by MeadWestvaco), REAX 100M (sodium salt of chemically modified low molecular weight Kraft lignin polymer, sold by MeadWestvaco) and Kraftspearse DD-5 (chemically modified high molecular weight Kraft lignin polymer) Sodium salt, sold by MeadWestvaco).

The compositions of the present invention, in addition to the lignosulfonate, may also include one or more additional ingredients to formulate additional surfactants. These additional surfactant materials include dispersants and wetting agents. The surfactant may be nonionic or ionic, such as anionic, and may include polymeric groups such as polyoxyethylation. Suitable surfactants are described in McCutcheon's Detergents and Emulsifiers Annual , Allured Publ. Corp., Ridgewood, NJ, and Sisely and Wood, Encyclopedia of Surface Active Agents , Chemical Publ. Co., Inc., New York, 1964. Examples of suitable surfactants include polyethoxylated alcohols, polyethoxylated phenols, polyethoxylated fatty acid sorbitan esters, polyethoxylated fatty acid sorbitan esters, dialkyl sulfosuccinates , alkyl sulfate, alkyl benzene sulfonate, organic oxime, N, N-dialkyl taurate, lignosulfonate, naphthalene sulfonate, formaldehyde condensate, polycarboxylate, glycerin Esters, polyoxyethylene/polyoxypropylene block copolymers and alkyl polyglycosides (wherein the number of glucose units, referred to as the degree of polymerization (DP), can range from 1 to 3, while alkyl units can range from C ₆ to C ₁₄ (see Pure and Applied Chemistry 72, 1255-1264).

The amount of surfactant present will depend on the particular surfactant used. For example, the lignosulfonate may be present in an amount of from 0.1 to 15% by weight of the microcapsules, preferably from 0.5 to 10% by weight.

The compositions of the present invention may further comprise other components known in the art and included in such compositions. For example, the composition can include one or more components that adjust the viscosity of the liquid phase. Suitable viscosity modifiers are known in the art and include ethyl cellulose, trisin, polyvinyl alcohol and sodium polyacrylate.

In an exemplified embodiment, the compositions of the present invention are prepared from the following components (parts are expressed in parts by weight): extrinsable: 1 to 10 parts; microcapsules having outer walls including: cellulose derived : 0.4 to 1 part; natural rubber: 1.6 to 4 parts; gelatin: 2 to 5 parts; and cross-linking agent: 2 to 5 parts; emulsifier: 1-4 parts; liquid carrier: 40-99 parts; Agent: 1-3 parts; viscosity modifier: 2-8 parts; and water: 140 to 160 parts

In another aspect, the invention also provides a method of making the above composition. Accordingly, there is provided a method of preparing a microencapsulated tracable composition comprising: a) preparing an aqueous solution of a cellulose derivative and a natural gum; b) adding a traceable and liquid carrier to the step ( a) the prepared solution is stirred and formed to form an emulsion comprising an aqueous immiscible phase in water; c) preparing a gelatin aqueous solution; and d) combining the solution prepared in the step (c) with the emulsion prepared in the step (b).

In the method of the present invention, a complex coacervation technique is used to form microcapsules whereby the encapsulation can annihilate the active ingredient.

In step (a) of the process, a solution of a cellulose derivative and a natural gum in water is formed. In step (b), the eliminable and liquid carrier is added to the aqueous solution. In a preferred embodiment, the eliminator is dissolved in a liquid carrier. If desired, one or more emulsifiers and/or stabilizers may be added to the mixture. The resulting mixture is stirred, as is known in the art, to form a stable emulsion comprising a dispersion of water immiscible microdroplets in a continuous aqueous phase.

A solution of gelatin in water is formed in step (c). The resulting solution is combined with the above emulsion, preferably mixed. The result of this combination is to form an outer wall having a cellulose derivative, natural gum and gelatin and containing microvoids which are destructible. In order to allow the formation of microcapsules, the mixture can be heated when combined. Suitable temperatures will depend on factors such as the components used. Typical temperatures are in the range of 25 to 65 ° C, more preferably 35 to 55 ° C. The pH of the gelatin mixture can be adjusted, preferably to provide acidic conditions. The acidic conditions can be obtained by adding a suitable acid to the mixture. Weak acids are preferred, such as carboxylic acid, especially a C ₁ to C ₄ carboxylic acid, wherein a suitable acid is acetic acid. The pH is preferably adjusted to below 5.5, more preferably below 5.0, especially in the range of from 3 to 4.5. The reaction period required to form the microcapsules will depend on the components and the reaction conditions. A typical reaction period is from 30 to 70 minutes, more preferably from 40 to 60 minutes. The reaction may proceed at low temperatures, for example at about room temperature.

As known above, the wall of the microcapsule preferably comprises a crosslinking agent. Thus, in a preferred embodiment, the process of the present invention comprises the additional step of: e) adding a crosslinking agent to the resulting mixture.

The mixture produced by step (d) is preferably cooled prior to the addition of the crosslinking agent. A temperature in the range of 0 to 10 ° C is used, more preferably 0 to 5 ° C. Further, it is preferred to increase the pH of the resulting mixture, more preferably alkaline. Can use pH up to 9, more Good land 8 to 10. The pH can be increased by adding a suitable base. Suitable bases are known to the art and include Group I metal hydroxides. Sodium hydroxide is a particularly suitable base. A suitable reaction period for the formation of the crosslinked wall material is from 30 to 70 minutes, more preferably from 40 to 60 minutes. The reaction may proceed at elevated temperatures, for example at about 30 to 50 ° C, to allow the formation of wall materials.

Additional components included in the composition, such as tackifiers, can be introduced into the composition once the outer wall formation reaction has been completed.

In the method of the present invention, the microcapsule wall is formed by a coacervation method, particularly in which a water-soluble polymer electrolyte having an opposite charge is used in a known manner. In the present invention, an amphoteric polymer electrolyte, in particular gelatin, is used. Gelatin is positively charged (by adjusting the pH) when it is below the isoelectric point. This gelatin is mixed with a negatively charged aqueous solution of a cellulose derivative and a natural gum. Negatively charged gelatin reacts with positively charged cellulose derivatives and natural gums. As a result of the complex coacervation, cellulose derivatives such as sodium carboxymethylcellulose, natural gums such as acacia and gelatin form wall materials of microcapsules.

An embodiment of the method of the present invention can be summarized as including the following steps:

a. Preparation of an emulsion: dissolving sodium carboxymethylcellulose and gum arabic in deionized water; adding a traceable, emulsifier, liquid carrier and optionally one or more stabilizers; using an impeller by stirring to 3000 to 10000r The speed of /min is homogenized by rotation for 5 to 30 minutes to form a stable oil-in-water emulsion A.

b. Coacervation method: The gelatin is dissolved in deionized water to form a solution B.

c. Solution B is thoroughly mixed with Emulsion A at a temperature of 35 to 55 ° C; the pH is adjusted to 3 to 4.5 by the addition of 10% acetic acid; and mixture C is maintained at room temperature for 40 to 60 minutes.

d. cross-linking: cooling the mixture C to a temperature of 0 to 5 ° C; adding a 20% sodium hydroxide solution to adjust the pH to a range of 8 to 10; adding a crosslinking agent; allowing the resulting mixture to react for 40 to 60 min; and then Slowly warm to 30-50 °C.

The prepared microcapsules can be formulated in any suitable manner. Formulations and formulation techniques suitable for such microcapsules are known in the art. Soluble in a suitable diluent (preferably, water) The suspension or slurry of the capsule is a preferred embodiment for transporting, storing and finally dispersing the composition in the area to be treated. These formulations were applied using conventional spray devices.

Aqueous suspensions may include suspending agents therein, such as crosslinked acrylic acid interpolymers, as discussed in US Pat. No. 3,426,004, other suspending agents, such as hydroxyethylcellulose, gum, clay, submicron sized oxime, and others. Inorganic substances; wetting agents and dispersing agents such as detergents, polyvinyl alcohol, gelatin, methyl cellulose, casein and clay. In addition, the formulation may include so-called "adhesives", even if the capsule adheres to the leaves of the treated plant and does not drip onto the ground, such as gelatin, bentonite, gum, polysulfide, polyacrylic acid. And mineral oils and animal fats.

This formulation can be applied directly to the target area. Alternatively, the composition can be further diluted prior to administration. For example, an aqueous dispersion, suspension or slurry suitable for transport and storage consists of from about 10 to 30% by weight of microcapsules, more preferably about 25% of a pesticide-containing capsule, which is diluted with water to About 1% by weight for spraying.

It has been found that the formulations of the present invention have a high degree of stability during shipping and storage.

The composition of the present invention can be used in a place to prevent unwanted plant growth.

Thus, in another aspect, the invention provides a method of controlling plant growth in a locus comprising applying a composition as described above to the locus.

The invention further provides the use of the compositions described above for controlling plant growth.

The composition may be applied to the area where the plant is to be grown, before or after the emergence of the target plant, for example by spraying on the surface of the soil or on the leaves of the plant. If desired, the user can mix the formulation into the upper soil by farming.

As indicated above, the compositions of the present invention are particularly suitable for formulations which can be eliminated. The eliminator can be formulated and/or applied with other compatible active ingredients including herbicides, insecticides, fungicides, nematicides, plant growth regulators, safeners, fertilizers and other agricultural chemicals. Acetochlor, alachlor, and metolachlor are mixed with the extrudate A preferred herbicide.

When other active agents are administered with the formulations of the present invention, either alone or in combination with other agricultural chemicals, an effective amount of each active ingredient is employed. Depending on the proportion of ingredients added to the extinction and other factors, such as the type of soil, the expected rainfall and irrigation pattern, the type of plant to be controlled, and the crop being grown (if any), the effective amount is variable. of.

Generally, it can be used in a uniform application from about 0.01 to about 2.0 kg per hectare, more preferably from about 0.3 to 1.5 kg per hectare. In general, the rate of application in the field is about two to four times that of the greenhouse.

For the purposes of illustration, the invention is further described by the following examples.

Example 1

This example illustrates the preparation of specific acetylene urea derivatives that can be used to form the present microcapsules. Unless otherwise stated, the amounts shown are by weight.

Preparation of acetylene urea

765 parts of urea and 875 parts of water were introduced into a suitable reaction vessel equipped with a stirrer, a thermometer and a reflux condenser. To the slurry, 282 parts of concentrated sulfuric acid was added and the mixture was heated to 70 °C. At 70 ° C, 605 parts of glyoxal (40% aqueous solution and no formaldehyde) were slowly added to the clear solution to maintain the reaction temperature between 75 ° and 80 ° C. After the addition of glyoxal, the reaction mixture was maintained at 75 ° C for 1 hour and then cooled. The separated crystalline acetylene urea was filtered and washed with water and a dilute aqueous caustic solution.

The acetylene urea obtained after drying had a melting point of 298 to 300 ° C and a yield of 88% (525 parts).

Preparation of tetramethylol acetylene urea

A suitable reaction vessel equipped with a stirrer, a thermometer and a reflux condenser was introduced with 688 parts (10 mol) of aqueous formaldehyde solution (44%), and the pH was adjusted to 8.7 with 22 parts of a 0.5 N NaOH solution. In this solution, 284 parts (2 mol) of acetylene urea was added at 40 °C. During the reaction, the temperature was raised to 55 °C. At this stage, most of the acetylene urea enters the solution. The pH was adjusted to 8.0 with 5 parts of 0.5 N NaOH for approximately 15 minutes. A clear, pale yellow solution was obtained. The clarified solution was distilled under reduced pressure at 50 ° C, and the water was removed until the contents of the reaction vessel were about 640 parts. The slurry formed in the vessel was poured into 800 parts of methanol. The resulting white crystal precipitate was filtered and dried.

The total yield of tetramethylol acetylene urea was 483 parts (92%) and had a melting point of 132-136 °C.

Preparation of dimethoxymethyldiethoxymethylacetylene urea

A suitable reaction vessel equipped with the apparatus described above was charged with 320 parts (10 mol) of methanol, 460 parts of ethanol (10 mol) and 20 parts of 70% concentrated nitric acid. To this acidic alcohol mixture, 262 parts (1 mol) of tetramethylol acetylene urea was charged and the mixture was heated to 40 ° C with stirring. After about 20 minutes, all of the tetramethylol acetylene urea has entered the solution. When the reaction mixture became clear, it was cooled to 22 ° C and 45 parts of a 20% sodium hydroxide solution was added to neutralize the reaction mixture to a pH of 7-8. The neutralized clear solution was slowly heated to 105 ° C under reduced pressure to remove substantially all of the alcohol-water mixture. The resulting slurry was filtered hot at 80 ° C to remove inorganic salts and other impurities.

The yield of the dimethoxymethyldiethoxymethylacetylene urea in the form of a slurry was 320 parts. The structure of this product was confirmed by nuclear magnetic resonance spectroscopy. The disc solid was 95.0% and the flake solid was 98.5%. The Gardner-Holdt viscosity is Z ₃ -Z ₄ (at 25 ° C). This product is soluble in water as well as benzene.

Preparation of methylated ethylated acetylene urea

142 parts (1 mol) of acetylene urea and 300 parts (4.4 mol) of aqueous formaldehyde solution (44%) were introduced into a suitable reaction vessel equipped with the above apparatus. The pH was adjusted to 7.5-8.0 with about 6 parts of a 0.5 N NaOH solution. The reaction mixture was heated to 80 °C for 15 minutes. The pH of the reaction mixture was again adjusted to about 7-7.5 with a 0.5 N NaOH solution. The resulting pale yellow solution of tetramethylol acetylene urea was distilled under reduced pressure at 50 ° C until the weight of the slurry in the reaction solution was about 305-310 parts. Into this slurry, 160 parts (5 mol) of methanol and 6 parts of concentrated nitric acid were added at 50 °C. There was a slight exotherm after the addition. The reaction temperature was maintained at about 55-60 °C for 30 minutes and then cooled to 22 °C. The resulting mixture was neutralized with a 20% NaOH solution to a pH of 7-8 and then heated to 105 °C under reduced pressure to remove substantially all of the alcohol and water. To the resulting slurry was added 92 parts (2 mol) of ethanol and 4 parts of nitric acid and the load was heated to about 70 °C. The reaction mixture was maintained at this temperature for 30 minutes. After the reaction mixture was cooled to 22 ° C, it was neutralized to a pH of 7.5 using a 20% NaOH solution. The neutralized solution was slowly heated to 105 ° C under reduced pressure to remove all of the alcohol-water mixture. The resulting slurry was filtered hot at 80 ° C to remove inorganic salts and other impurities.

The yield of the slurry was 320 g. The flake solid was 99.5% and the product was soluble in water. Nuclear magnetic resonance analysis showed that the ratio of methoxy group to ethoxy group in the product was 1:0.63, that is, the average degree of methylation of about 2.4 and the degree of ethylation of 1.6.

The process for preparing methylated ethylated acetylene urea was repeated in all basic details except that 138 parts (3 moles) of ethanol were used during the second alkylation step. The final slurry product is soluble in water. The flake solids were 99%. Nuclear magnetic resonance analysis showed that the ratio of methoxy group to ethoxy group in the product was 1:0.81, respectively. This product is soluble in water and is also soluble in benzene.

Preparation of methylated butylated acetylene urea

In addition to reacting methylolated acetylene urea with 192 parts (6 mol) of methanol, the above-mentioned preparation of methylated ethylated acetylene urea is repeated in all basic details. law.

The second alkylation stage was carried out with n-butane as follows: 74 parts (1 mol) of n-butanol and 1 part of nitric acid were added to the slurry obtained after the methylation step. The reaction mixture was heated to 105 ° C for 1 and a half hours. The distillate, which appeared to be methanol, was removed using a Dean-Stark separator. The light yellow solution was cooled to 20 ° C and neutralized to a pH of 7-7.5 with a 0.5 N NaOH solution. Unreacted butanol and any water in the reaction mixture were removed under reduced pressure at 121 °C.

The approximately 100% solid viscous liquid produced by N.M.R. analysis showed a ratio of methoxy:butoxy groups of 1:0.32, i.e., an average degree of methylation of about 3, and a degree of butylation of 1.0. The product remained liquid and did not crystallize when stored at ambient temperature. This product is slightly soluble in water but soluble in benzene.

Example 2

Various examples of the compositions of the present invention were prepared as shown in Examples A through E below. The components used to prepare Examples A through E are summarized in the following table:

Examples A to E of the emulsifier is POE (20) sorbitan trioleate nonionic surfactant (e.g. Uniqema; TWEEN 85 ^TM), and POE (40) sorbitol hexaoleate nonionic surfactant (eg Uniqema; ATLAS G1086 ^TM ).

The liquid carrier is a C ₁₆ -C ₁₈ fatty acid methyl ester (e.g. the company Cognis; AGNIQUE ME 18SDU ^TM).

The stabilizer used was a lignosulfonate (e.g. MeadWestvaco Corporation; REAX 88A ^TM).

The crosslinkers of tetrakis (methoxymethyl) glycoluril (Powderlink 1174 ^TM).

The thickening agent used in the examples is Sanxian gum.

The compositions of Examples A through E were prepared using the following general methods:

a. Preparation of an emulsion: dissolving sodium carboxymethylcellulose and gum arabic in deionized water; adding a traceable, emulsifier, liquid carrier and stabilizer; rotating the impeller at a speed of 3000 to 10000 r/min by stirring Homogenized for 5 to 30 minutes to form a stable oil-in-water emulsion A.

b. Coacervation method: The gelatin is dissolved in deionized water to form a solution B.

c. Solution B is thoroughly mixed with Emulsion A at a temperature of 35 to 55 ° C; the pH is adjusted to 3 to 4.5 by the addition of 10% acetic acid; and mixture C is maintained at room temperature for 40 to 60 minutes.

d. cross-linking: cooling the mixture C to a temperature of 0 to 5 ° C; adding a 20% sodium hydroxide solution to adjust the pH to a range of 8 to 10; adding a crosslinking agent; allowing the resulting mixture to react for 40 to 60 min; and then Slowly warm to 30-50 °C.

e. A thickening agent is added to the reaction mixture.

In each of Examples A through E, the resulting composition comprised a microcapsule having a stable outer wall and containing a traceable. When applied to a plant in a locus, the microcapsules have a favorable rate of release of the mimetic active ingredient, with little or no extinction drifting to adjacent areas. This eliminator has at least as high a growth and control activity as planted EC formulations.

Claims (27)

A composition comprising a microencapsulated clomazone, the traceable system comprising microcapsules having microcapsule walls formed by coacervation of a plurality of amphoteric polymer electrolytes, wherein the microcapsules comprise A crosslinking agent, and the crosslinking agent is a glycoluril resin. The composition of claim 1, wherein the traceable is contained in a microcapsule having a capsule wall formed of a cellulose derivative, a natural gum, and gelatin. The composition of claim 1 or 2, wherein the cellulose derivative comprises carboxyalkyl cellulose or a salt thereof, and the natural gum comprises gum arabic, gum ghatti, and tragacanth , karaya gum or a mixture thereof. The composition of claim 3, wherein the cellulose derivative comprises carboxymethylcellulose. The composition of claim 1 or 2, wherein the cellulose derivative is present in the microcapsule wall in an amount of from 1 to 30% by weight; the natural gum is present in an amount of from 5 to 75% by weight In the microcapsule wall; and the gelatin is present in the microcapsule wall in an amount of from 5 to 90% by weight. The composition of claim 1, wherein the glycoluril resin is of the following formula (I): Wherein R ₁ , R ₂ , R ₃ and R ₄ each independently represent a hydrogen atom or an alkyl group. The composition of claim 6, wherein R ₁ , R ₂ , R ₃ and R ₄ each independently represent an alkyl group having 1 to 12 carbon atoms. The composition of claim 1, wherein the crosslinking agent is present in the microcapsule wall in an amount of from 5 to 90% by weight. The composition of claim 1, wherein the cellulose derivative, natural rubber, gelatin and cross-linking agent are present in the microcapsules in a weight ratio of 0.4:1.6:2:2 to 1:4:5:5. In the wall. The composition of claim 1 or 2, wherein the traceable system is combined with a liquid carrier and is present in the microcapsules. The composition of claim 10, wherein the traceable is dissolved in a liquid carrier. The composition of claim 10, wherein the liquid carrier is a fatty acid ester of an alkanol. The composition of claim 1 or 2 further includes a stabilizer. The composition of claim 13, wherein the stabilizer is a lignosulfonate. A method of preparing a microencapsulated extrudable composition according to claim 1 of the patent application, which comprises extruding by agglomeration of a plurality of amphoteric polymer electrolytes. The method of claim 15, wherein the method comprises: a) preparing an aqueous solution of the cellulose derivative and the natural gum; b) adding the traceable and liquid carrier to the solution prepared in the step (a) and Stirring to form an emulsion comprising water immiscible phase in water; c) preparing a gelatin aqueous solution d) combining the solution prepared in step (c) with the emulsion prepared in step (b); and e) in the resulting mixture Add a crosslinking agent. The method of claim 16, wherein the eliminator is dissolved in a liquid carrier. The method of claim 16 or 17, wherein the pH of the gelatin solution in the step (c) is adjusted to less than 5.5. The method of claim 16 or 17, wherein the cellulose derivative comprises a carboxyalkyl cellulose or a salt thereof, and the natural gum comprises gum arabic, gum ghatti, tragacanth, karaya gum or Its mixture. The method of claim 19, wherein the cellulose derivative comprises carboxymethylcellulose. The method of claim 16 or 17, wherein the mixture produced in the step (d) is cooled to a temperature of from 0 to 10 ° C before the crosslinking agent is added. The method of claim 16 or 17, wherein the glycoluril resin is of the following formula (I): Wherein R ₁ , R ₂ , R ₃ and R ₄ each independently represent a hydrogen atom or an alkyl group. The method of claim 22, wherein R ₁ , R ₂ , R ₃ and R ₄ each independently represent an alkyl group having 1 to 12 carbon atoms. A suspension formulation comprising the composition of any one of claims 1 to 14. Use of a composition according to any one of claims 1 to 14 for controlling plant growth in a locus. A use of a formulation according to claim 24 of the patent application is for controlling plant growth in a site. A method for controlling plant growth in a locus comprises applying a composition as claimed in any one of claims 1 to 14 or a formulation as in claim 24 of the patent application.