JPH0485B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention involves dissolving polymethylene polyphenyl isocyanate in a water-immiscible material, which is the material to be encapsulated, and dissolving the resulting mixture in an aqueous phase containing an emulsifier selected from the group consisting of salts of lignin sulfonates. dispersing and then adding a polyfunctional amine and reacting the amine with polymethylene polyphenyl isocyanate to form an oil-insoluble polyurea microcapsule wall around the water-immiscible material at the oil/water interface. A process for producing small or microcapsules containing water-immiscible substances, including: The capsules can be manufactured to any desired size, for example from 1μ up to 100μ or more. Preferably, the size of the microcapsules is from about 1 to about 1 in diameter.
It is in the range of 50μ. Such capsules have a variety of uses, containing, for example, dyes, inks, chemical reagents, pharmaceuticals, fragrances, pesticides, herbicides, and the like. Any liquid, oil, meltable solid or solvent soluble material that is capable of dissolving the polymethylene polyphenyl isocyanate and is non-reactive with said isocyanate can be encapsulated by this method. Once encapsulated, liquids or other forms can destroy, shatter, or destroy the capsule skin.
It is stored until it is released by some means, such as melting, dissolving or otherwise removing it, or by mechanical means, or until release by diffusion occurs under suitable conditions. The process of the invention is particularly suitable for the production of herbicides containing microcapsules of very small particle size suspended in an aqueous solution. Aqueous dispersions of pesticide and herbicide microcapsules are particularly useful in controlled release pesticide and herbicide formulations. This is because they can be diluted with water or liquid fertilizer and sprayed with conventional equipment, thereby forming a uniform field coverage of the pesticide or herbicide. Additives such as film formers can be added directly to the final formulation to improve the adhesion of the microcapsules to the leaf surface. In some cases, reduced toxicity and prolonged activity of encapsulated herbicides and pesticides has been observed. Various techniques have been used or proposed for packaging. In one such method, known as "simple coacervation", the reaction is carried out by the action of a precipitating agent (e.g. a salt or a non-solvent for the polymer) which reduces the solubility of the polymer in the solvent. Separating the polymer from a solution of the polymer in a solvent. Patent documents describing such methods and their shell wall materials include:
U.S. Patent No. 2800458 (Hydrophilic Colloid);
No. 3069370 and No. 3116216 (polymer zein),
Same No. 3137631 (denatured protein) and No. 3418250
No. (Hydrophobic Thermoplastic Resin) Specifications and others. Other methods include the formation of microcapsules based on in situ interfacial condensation polymerization. UK patent no.
No. 1,371,179 discloses a process comprising dispersing in an aqueous phase an organic pesticide phase containing polymethylene polyphenyl isocyanate or toluene diisocyanate monomers.
This wall-forming reaction continues in this batch up to a high temperature point where the isocyanate monomers are hydrolyzed at the interface to form amines, which then react with the non-hydrolyzed isocyanate monomers to form the polyurea microcapsule walls. It is started by heating. One difficulty with this method is the potential for continued reaction of the monomers after packaging. If all monomers do not react during production, hydrolysis of isocyanate monomers continues to generate _CO2 .
This results in the development of pressure when the formulation is packaged. Various encapsulation methods are known by interfacial condensation between directly acting complementary reaction components. Among these methods are reactions that produce various types of polymers as capsule walls. Many such reactions for the production of coating materials involve an amine, which must be of at least difunctional character, and a second reaction, which for the production of polyurea, is a difunctional or polyfunctional isocyanate. It is carried out between components and intermediates. The amines primarily used or proposed for these methods are typically exemplified by ethylenediamine having at least two primary amino groups. US Pat. No. 3,429,827 and US Pat. No. 3,577,515 are examples of encapsulation by interfacial condensation. For example, U.S. Pat. No. 3,577,515 requires a first reactant and a complementary second reactant to the first reactant and each reactant in a separate phase, so that the first and a continuous or batch method in which the second reactant reacts at the interface between the droplets to form encapsulated droplets. This method is applicable to many types of polycondensation reactions, ie, to many different combinations of reaction components that can interfacially condense from their respective phase liquids to form solid films at the liquid interface. The resulting capsule skin is made of polyamide, polysulfonamide,
It is produced as a mixture of the reactants in one or both phases to produce a polyester, polycarbonate, polyurethane, polyurea or corresponding condensation copolymer. This reference discloses that diamines or polyamines (e.g. ethylene diamine, phenylene diamine, toluene diamine, hexamethylene diamine, etc.) are present in the aqueous phase and diisocyanates or polyisocyanates (e.g. toluene diisocyanate, hexamethylene diisocyanate and polymethylene polyisocyanate) are present in the aqueous phase. The formation of polyurea skins when present in an organic oil phase is described. In the practice of US Pat. No. 3,577,515, the primary liquid is a continuous phase liquid. That is, when forming oil-containing microcapsules, an aqueous liquid is predominant, and when water-encapsulated microcapsules are formed, an oil phase is predominant. Although a number of methods are available in the art of manufacturing microencapsulated pesticide and herbicide formulations, various disadvantages exist with respect to prior art methods. Encapsulation materials produced by the in situ interfacial polymerization method of GB 1371179 require post-treatment to prevent continued carbon dioxide evolution and excessive caking, thereby reducing the final product. Increase costs. In many encapsulation methods, it is often necessary to separate the encapsulated material from the molding medium. During this separation process the capsule wall is subjected to large stresses and strains, which can result in premature rupture of the capsule and concomitant loss of encapsulating material. They also lack practical value in various other respects. Various experiments have demonstrated the difficulty of establishing the desired capsules in a free-standing manner and of avoiding the partially formed capsules from agglomerating into a heterogeneous mass of material lacking clear capsule formation. There is. Very low concentrations of the intended product are often obtained relative to the total mixture. The present invention provides a new and improved encapsulation method that is quick, effective, and eliminates the need to separate the encapsulation material from the continuous phase liquid. The present invention also eliminates the need to use strong solvents in the organic phase, resulting in savings in energy and packaging and equipment consumption. Furthermore, direct combinations of water-based herbicide and pesticidal formulations with other water-based pesticides are possible. A critical characteristic of the present invention is the use of lignin sulfonate emulsifiers, especially lignin sulfonate salts such as sodium, potassium, magnesium, calcium or It consists in using ammonium salts. Generally per total composition
480g or more of a water-immiscible substance is present. Through the use of certain emulsifiers described herein, it is possible to retain the final microcapsules in the initial aqueous solution, thus eliminating the additional step of separating the microcapsules from the initial aqueous environment. Is possible. The final microcapsules do not agglomerate and the aqueous capsule body does not solidify upon further long-term storage or short-term exposure to elevated temperatures. The invention is particularly advantageous when used in the encapsulation of herbicides, especially acetanilide and thiocarbamate herbicides such as alachlor, butachlor, propachlor, trialate, dialate, and the like. Experiments have shown that conventional oil/water herbicide emulsions are sufficient to achieve microencapsulation of concentrated amounts of herbicide material when amines are added and sufficient to exclude solidification of the oil/water mass. It can be seen that it is not possible to produce a stable emulsion. Furthermore, concentrated amounts of acetanilide and thiocarbamate herbicides, e.g., 4-5 pounds per gallon (480-700 g/), can be encapsulated using traditional interfacial polymerization techniques, e.g., as disclosed in U.S. Pat. No. 3,577,515. Attempts to do so have resulted in unsatisfactory formulations due to problems with excessive herbicide crystal growth as well as problems with agglomeration or solidification of the final suspension. It was believed that herbicide crystal growth resulted from incomplete encapsulation of the herbicide material or from passage of small amounts of herbicide through the polymer shell wall. This problem is particularly acute with respect to acetanilide herbicides. Crystal growth is highly undesirable. The reason is that once it occurs, the final formulation cannot be used directly. Rather, the microcapsules must be separated from the aqueous solution and resuspended in water, after which it can be sprayed in conventional agricultural herbicide and fertilizer spray equipment. Therefore, 480 g or more of acetanilide herbicides such as alachlor, propachlor, butachlor, etc. and thiocarbamate herbicides such as trialate, dialate, etc. per total composition are encapsulated within the walls of the polyurea shell, with the final microcapsules being encapsulated within the walls of the polyurea shell. It is a particular object of the present invention to provide a method in which the suspension is suspended in an initial aqueous solution. Suspended microcapsules can be stored for long periods of time without causing agglomeration or solidification of the aqueous capsule formulation or excessive herbicide crystal growth, and can be exposed to elevated temperatures for short periods of time. The present invention relates to a method for encapsulating water immiscible materials in polyurea shell walls. The method of the invention first involves providing an aqueous solution containing an emulsifier selected from the group consisting of lignin sulfonate salts, such as sodium, potassium, magnesium, calcium or ammonium salts. Particularly effective for use herein are the sodium salts of lignin sulfonates. A water-immiscible substance (substance to be encapsulated) and a water-immiscible (organic) phase consisting of polymethylene polyphenyl isocyanate are added to this aqueous phase with stirring; to form a dispersion of. A polyfunctional amine, preferably 1,6-hexamethylene diamine, is then added to the organic/aqueous dispersion with continuous stirring. This polyfunctional amine reacts with the polymethylene polyphenyl isocyanate to form an encapsulated polyurea shell around the water immiscible material. The water-immiscible material referred to herein is the material to be encapsulated and which is suitably capable of dissolving the polymethylene polyphenyl isocyanate and yet being non-reactive thereto. Any liquid, oil, meltable solid or solvent-soluble substance. Such water-immiscible substances include, for example, herbicides such as α-chloro-2′,6′-diethyl-N-methoxymethylacetanilide (commonly known as alachlor), N-(butoxymethyl)-2- Chloro-2′,6′-
Diethylacetanilide (commonly known as butachlor), α-chloro-N-isopropylacetanilide (commonly known as propachlor), 2'-methyl-6'-ethyl-N-(1-methoxyprop-2-yl) )-2-chloroacetanilide (commonly known as metolachlor), 2'-tert-butyl-2-chloro-N-(methoxymethyl-6'-methylacetanilide, α-chloro-2'-ethyl-6 '-Methyl-N-
(1-Methyl-2-methoxyethyl)acetanilide, α-chloro-N-(2-methoxy-6-methylphenyl)-N-(1-methylethoxymethyl)acetamide, α-chloro-N-methyl-N-[ 2-methyl-
6-(3-methylbutoxy)phenyl]acetamide, α-chloro-N-[2-methyl-6-(2-methylpropoxy)phenyl]-N-(propoxymethyl)acetamide, N-[(acetylamino)methyl ]-α-chloro-N-(2,6-diethylphenyl)acetamide, α-chloro-N-methyl-N-(2-methyl-
6-propoxyphenyl)acetamide, N-(2-butoxy-6-methylphenyl)-α
-Chloro-N-methylacetamide, (2,4-dichlorophenoxy)acetic acid isobutyl ester, 2-chloro-N-(ethoxymethyl)-6'-ethyl-o-acetatoluidide (commonly known as acetochlor) , 1-(1-cyclohexen-1-yl)-3-
(2-fluorophenyl)-1-methylurea, S-2,3,3-trichloroallyl-diisopropylthiocarbamate (commonly known as trialate), S-2,3-dichloroallyl-diisopropylthiocarbamate (commonly known as diallate), α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine (commonly known as trifulurin), 2-chloro-4- ethylamino-6-isopropylamino-1,3,5-triazine (commonly known as atrazine), 2-chloro-4,6-bis(ethylamino)-
S-triazine (commonly known as simazine), 2-chloro-4,6-bis(isopropylamino)-S-triazine (commonly known as propazine), 4-amino-6-(1,1 -dimethylethyl)-
3-(methylthio)-1,2,4-triazine-5
(4H)one (commonly known as metribuzin), N'-(3,4-dichlorophenyl)-N-methoxy-N-methylurea (commonly known as linuron), α-chloro-N -(ethoxymethyl)-N-[2
-Methyl-6-(trifluoromethyl)phenyl]
acetamide; ), herbicide safety agents (antidotes) such as ethyl 2-chloro-4-(trifluoromethyl)
-5-triazole carboxylate, benzyl 2-chloro-4-(trifluoromethyl)-5-thiazole carboxylate, and organic solvents such as xylene and are specifically contemplated herein. In the practice of preferred embodiments of the invention, the substance to be encapsulated is a herbicide, particularly an acetanilide or thiocarbamate herbicide, and more particularly alachlor, butachlor, propachlor,
Trialate and dialate herbicides. The material to be encapsulated using the method of the invention need not consist of only one type. This is 2
It may be a combination of species or more of various types of water immiscible substances. Such combinations, for example when using suitable water-immiscible substances, are active herbicides and other active herbicides, or active herbicides and active insecticides. Also contemplated are water-immiscible materials to be encapsulated, including active ingredients such as herbicides and inert ingredients such as solvents or additives. The water-immiscible material containing dissolved polymethylene polyphenyl isocyanate includes a water-immiscible or organic phase. The water-immiscible material acts as a solvent for the polymethylene polyphenyl isocyanate, i.e. excluding the use of other water-immiscible organic solvents and providing a concentrated amount of water-immiscible material in the final encapsulation product. Make it possible. The water-immiscible substance and the polymethylene polyphenyl isocyanate are simultaneously added in premixed form to the aqueous phase. That is, the water-immiscible material and the polymethylene polyphenyl isocyanate are premixed to form a homogeneous water-immiscible phase before being added to the aqueous phase and emulsified. The concentration of water-immiscible material initially present in the water-immiscible phase should be sufficient to provide at least 480 grams of water-immiscible material per aqueous solution. However, this is in no way limiting and larger amounts can be used. In practical operation, as those skilled in the art will recognize, the use of very high concentrations of water-immiscible materials will result in very thick microcapsule suspensions. Generally, the concentration of water immiscible material will range from about 480 grams to about 700 grams per total composition. The preferred range is from about 480 to 1 per total composition.
It is approximately 500g. A polyisocyanate useful in this process is polymethylene polyphenyl isocyanate. Suitable for use herein are commercially available polymethylene polyphenyl isocyanates;
Examples include PAPI and PAPI-135 (an Apzilon product) and Mondur MR (a Mobay Chemical Company product). Polyfunctional amines suitable for use in the present invention are amines that can react with polymethylene polyphenyl isocyanate to form a polyurea shell wall.
The polyfunctional amine should itself be water-soluble or in the form of a water-soluble salt. Polyfunctional amines that can be used can be selected from a wide variety of such materials. Suitable examples of polyfunctional amines that can be used in the present invention include, but are by no means limited to, the following: Ethylenediamine, propylenediamine, isopropylenediamine, hexamethylenediamine, toluenediamine, ethenediamine, triethylenetetraamine, tetraethylenepentamine, pentaethylenehexamine, diethylenetriamine, bishexamethylenetriamine, and others. The amines can be used alone or in combination with each other, preferably with 1,6-hexamethylene diamine (HMDA). 1,6-hexamethylene diamine is preferred for use in the method of the invention. The polymethylene polyphenyl isocyanate and the polyfunctional amine ultimately form a shell wall that encapsulates the water-immiscible material. The shell wall content of the capsules produced by this method is from about 5 to about 30%, preferably from 8 to 20%, by weight of the water-immiscible material;
and more particularly 10% by weight. The amounts of polymethylene polyphenyl isocyanate and polyfunctional amine used in the process are determined by the percent shell wall content produced. Generally, the reaction involves approximately
3.5 to about 21.0% polymethylene polyphenyl isocyanate and about 1.5 to about 9.0% amine are present. Preferably about 5.6 to about 13.9% polymethylene polyphenyl isocyanate and about 2.4 to about 6.1% amine relative to the weight of the water-immiscible material, and more particularly 7.0% polymethylene polyphenyl isocyanate and 3.0% amine present. Although excess amounts of polyfunctional amines relative to the amount of polymethylene polyphenyl isocyanate are used herein, stoichiometric amounts of polyfunctional amines may be used without departing from the spirit of the invention. It should be recognized that it can be used. Emulsifying agents (generally referred to herein as emulsifiers) that are critical for use in the practice of this invention are salts of lignin sulfonates, such as the sodium, potassium, magnesium, calcium or ammonium salts. In practicing the method of the invention, the sodium salt of lignin sulfonate is the preferred emulsifier. Commercially available emulsifiers of any of the above types that do not contain added surfactants can be conveniently used, and many are
Detergents and Emulsifier′s” (North American edition 1978)
(published by MC Publishing). Examples of commercially available emulsifiers are "Treax" LTS, LTK and LTM (products of Scott Paper Co.), "Treax" which are potassium, magnesium and sodium salts (50% aqueous solution) of lignosulfonates, respectively (Scott Paper Company products), "Malapers Marasperse) CR” and “Marasperse
CBOS-3” (sodium lignosulfonate,
Polyfon 0, Polyfon T, Reax 88B, Reax 85B lignin sulfonate sodium salt and Reax C-21
” lignin sulfonate calcium salt (a product of Westvaco Polychemicals). The range of emulsifier concentrations found to be best accepted in the system varies from about 1/2 to about 15%, and preferably from about 2 to about 6%, based on the weight of the water-immiscible material. Sodium lignosulfonate emulsifier is preferentially used at a concentration of 2% relative to the weight of the water-immiscible material. Higher emulsifier concentrations can be used but do not provide greater ease of dispersion. The microcapsules of the invention require no further processing, eg separation from the aqueous liquid. This can be used directly or combined with, for example, liquid fertilizers, pesticides, etc. to produce aqueous solutions that can be conveniently applied for agricultural use. Most often, it is most convenient to bottle or bottle the aqueous suspension containing the encapsulated water-immiscible material. In that case, it may be desirable to add formulation additives to the final aqueous solution of the microcapsules. Adding formulation additives such as thickeners, density modifiers, biocides, surfactants, dispersants, dyes, salts, antifreezes, corrosion inhibitors, etc. to improve stability and ease of application. I can do it. The formulator will recognize that the foregoing formulation additives are exemplary only and that other additives may be advantageously used in the compositions described herein. The method of the present invention is capable of providing satisfactory performance and production of encapsulation materials without adjustment to a specific PH. That is, there is no need to perform system PH adjustment during the packaging process. If it is desired to adjust the PH of the final microcapsule formulation, such as when combining the final microcapsule aqueous solution with other herbicides, pesticides, etc.
Conventional cooperative reagents or additives for adjusting acidity or alkalinity or other properties can be used, such as substances such as hydrochloric acid, sodium hydroxide, sodium carbonate, sodium bicarbonate, and the like. In practicing the process of this invention, the temperature should be maintained above the melting point of the water-immiscible material, but below the temperature at which the polymer shell begins to over-hydrolyze. For example, if it is desired to encapsulate a liquid organic solvent, the temperature of the process can be maintained at room temperature. If encapsulation of a fixed herbicide is desired, it is necessary to heat the herbicide to its molten state. For example, alachlor herbicide
Melts at 39.5-41.5℃. Therefore, the process temperature should be maintained above about 41.5°C. Generally the reaction temperature should not exceed about 80°C. This is because above this temperature the polymeric isocyanate monomer begins to rapidly hydrolyze resulting in loss of shell wall material. The agitation used to establish dispersion of the water-immiscible phase droplets in the aqueous phase can be provided by any means capable of imparting suitably high shear. Thus, any variable shear mixing device (eg, a blender) can be advantageously used to provide the desired agitation. The desired condensation reaction at the interface of the water-immiscible phase droplets and the aqueous phase occurs very quickly and is complete within a few minutes. That is, the formation of the polyurea capsule wall is complete, thereby completing the encapsulation of the water-immiscible material within the polyurea skin, and there is a usable encapsulated product suspended in the aqueous liquid. The particle size of microcapsules is approximately 1μ in diameter to approx.
In the range up to 100μ. Generally the smaller the particle size the better. An optimal range is about 1 to about 10 microns. About 5 to about 50μ is satisfactory for formulation. Particle size is controlled by the emulsifier used and the degree of agitation used. One convenient method of controlling the size of microcapsules is to adjust the stirring speed used to form a dispersion of water-immiscible phase droplets in the aqueous phase. The higher the stirring speed at this stage, the smaller the capsules obtained. Controlling capsule size by adjusting stirring speed is within the skill of those skilled in the art. The invention is further illustrated by the following examples which are intended to be illustrative and not of a limiting nature, and unless otherwise stated, the preparation of the final microcapsules in an aqueous suspension medium. No particle size change was observed over time. Example 1

[Table] 200 g of industrial chemical grade trialate containing 13.9 g of PAPI-135 was mixed with 141.3 g of water containing 4.0 g of Reax 88B sodium lignosulfonate.
emulsified into. Industrial chemical grade trialate and
PAPI−135 was kept at 50°C. Aqueous solution containing sodium lignosulfonate emulsifier is 50
It was warm at ℃. The emulsion was made using a Waring blender operated at high shear. In this emulsion
15.1 g of 40% HMDA was added to reduce shear at the same time. After 20 minutes, 132.0 g of ammonium sulfate was added and the formulation was bottled. The particle size of the resulting microcapsules ranged from 1 to 10 microns in diameter. The resulting formulation contained 500 g of encapsulated technical grade trialate per aqueous solution. Example 2

[Table] Containing 15.0g of PAPI held at 50℃
200g of industrial grade alachlor to 3.8g of Reax
Pour into 168.0 g of water containing 88B sodium lignosulfonate emulsifier. The emulsion is high shear and Brinkman Polytron.
It was formed in a square beaker using a homogenizer (the temperature in the beaker increased to 60°C as a result of the shear rate). 35% of 20.0g in this emulsion
HMDA was added and the shear was simultaneously reduced to low speed. The resulting formulation contained 527 grams of encapsulated technical grade alachlor per aqueous solution. The resulting microcapsules had a particle size of 1 to 10 microns in diameter. Approximately 20% liquid phase formed over time but was resuspended by gentle shaking. Example 3

Table: 200.0 g of technical grade alachlor containing 15.0 g of PAPI was emulsified in 155.9 g of water containing 3.8 g of Reax 88B sodium lignosulfonate. Industrial alachlor and PAPI are
It was maintained at 50°C. The aqueous solution containing the sodium lignosulfonate emulsifier was at room temperature. The emulsions were made using a work ring blender operated at high shear. 16.5g in this emulsion
of 40% HMDA and lowered the shear at the same time. After 20 minutes, ethylene glycol was added and the formula was bottled. Sedimentation occurred over time, but upon gentle shaking the settled layer was completely resuspended. When this formulation was passed through a 325 mesh screen (45μ aperture), only trace amounts of material larger than 45μ were observed. The procedure of Example 3 was repeated using various lignin sulfonate emulsifiers in place of Reax 88. These lignin sulfonate emulsifiers are Reax 85A, Reax C-21, Malaspers CB.
, Polyphon H, Polyphon O, Polyphon T, Reax 84A and Malasperse CBOS
-3. Example 4

TABLE All starting materials and Waring blender cups were kept at 70°C. 100.0g industrial grade propachlor (96.6g) containing 7.5g PAPI
%) was emulsified in 96.6 g of water containing 2.0 g of Reax 88B sodium lignosulfonate using a Waring blender operated at high shear. Add 9.3g of 35.8% HMDA to this emulsion,
and reduced shear at the same time. Capsules ranging in diameter from 1 to 60μ and mostly 1 to 20μ were produced. Example 5

Table: 100.0 g of technical grade butachlor (90%) containing 7.5 g of PAPI (both at room temperature) was added to 152.4 g of H ₂ O containing 2.0 g of Reax 88B sodium lignosulfonate using high shear. Emulsified. 9.3g of 35.8% HMDA was added to the emulsion and simultaneously lowered the shear. Spherical and irregularly shaped particles were observed in the size range 1-30μ in diameter and mostly 1-20μ. Example 6

【table】

[Table] Example 2 except that this example uses a Ross model 100L homogenizer and the beaker is placed in an ice bath to prevent its temperature from rising above 50°C.
Manufactured as in. High shear continued throughout. Shearing was continued for 20 minutes and then 17.1 g of ethylene glycol was added just before bottling. Almost all particles produced were less than 45μ in diameter. Only trace amounts of the substance
It did not pass through the 325 mesh screen (45μ maximum aperture). Example 7

[Table] 200.0 g of industrial grade alachlor containing 13.9 g of PAPI-135 was mixed with 4.0 g of Reax 88B water containing sodium lignosulfonate 166.1
emulsified in g. All components were kept at 50°C. The emulsion was made using a Waring blender operated at high shear. In this emulsion
15.1 g of 70% BHMTA was added and the shear was lowered at the same time. After 20 minutes, sodium chloride was added and the formula was bottled. The resulting microcapsules were primarily spherical particles with some irregularly shaped particles and ranged in size from 1 to 15 microns in diameter. Most of the particles were 1-10 microns in diameter. Example 8

[Table] ○R
Mondoul MR 3.6 15.0

[Table] Contains 13.0g of Mondoul MR at 50℃
200.0g of industrial grade alachlor (90%), 3.8
g of Reax 88B sodium lignosulfonate was emulsified in 165.4 g of water (both at room temperature). The emulsion was made using a Waring blender operated at high shear. 16.7 in this emulsion
g of HMDA (40%) was added and the shear was simultaneously reduced to provide gentle agitation. Ethylene glycol was added after 20 minutes. The irregularly shaped particles were 1-20μ in diameter, and the majority were 1-10μ in diameter. Example 9

[Table] 100 pounds of industrial grade alachlor (90%) was added to a 55 gallon drum at 60°C, and Ross type
7.5 pounds of PAPI was dissolved in this alachlor using a ME-105 homogenizer. 1.9
75.5 pounds of water containing 1 pound of Reax 88B was added to the drum without shear. An emulsion was then produced using a loss homogenizer to impart shear. 40% of 9.0 lbs in this emulsion
Added HMDA. After 20 minutes, 8.6 pounds of ethylene glycol was added and the formulation was filled into gallon containers. Predominantly spherical particles were formed with some irregular shape. These were 1-60μ in diameter and the majority were 1-20μ in diameter. Example 10

[Table] In this example, sodium chloride and 40%
All substances except HMDA were at 50°C. 200g of industrial grade alachlor (90%) containing 7.0g of PAPI-135 was mixed with 3.8g of Reax 88B.
Water containing sodium lignosulfonate
It was emulsified using a Waring blender operated at high shear in 169.0 g. 7.6g in this emulsion
of HMDA (40%) was added and the shear was simultaneously reduced to provide gentle agitation. After 20 minutes, 39.7 g of sodium chloride was added to balance the density of the aqueous phase to that of the suspended microcapsules. Diameter 1~20μ
Both spherical and irregularly shaped microcapsules were produced in the size range of . A particle has a diameter of
It was 80μ. Example 10 was repeated using diethylenetriamine, triethylenetetramine, tetraethylenepentamine and pentamethylenehexamine alone and in combination with 1,6-hexamethylene diamine. The combinations of amines and their respective concentrations are listed in Table 1 along with the amount of additional water if required.

【table】

【table】

[Table] Example 11 The microcapsules of this example were designed to produce a shell wall content of 6-30% relative to the amount of encapsulated herbicide.
Made by the method of Example 10 except that the amounts of PAPI and 40% HMDA were varied.

【table】 Example 12

[Table] This example illustrates the encapsulation of organic solvents. The order of addition of ingredients was the same as described in Example 1. All steps in this example were performed at room temperature. A Waring blender was used to provide moderate shear, which was reduced to gentle agitation after diamine addition.
The particle size of the produced microcapsules is 1 in diameter.
It was in the range of ~15μ. Example 13

【table】

[Table] In 1459.6 g of water containing 35.8 g of Reax 88B sodium lignosulfonate emulsifier,
A solution of 1351.4 g alachlor, 440.6 g metributin, and 124.6 g PAPI-135 were all
Emulsified at ℃. Polytron in a square container
Emulsions were produced using a PT1020 and Premier disperser. 135.3 g of 40% HMDA was added to the emulsion and the polytron shear was immediately stopped. After 10 minutes, 452.7 g of NaCl was dissolved in this suspension, which was then placed in a bottle. The particle size of the resulting spherical microcapsules ranged from 1 to 10 microns in diameter. Example 14

[Table] The manufacturing conditions were the same as in Example 12. The resulting microcapsules were spherical and ranged in diameter from 1 to 10 microns. Example 15

[Table] 13.9 g of PAPI in 187.0 g of water containing 8.6 g of Reax 88B sodium lignosulfonate
Parathion containing −135 dissolved in it
200.0g was emulsified. All ingredients were at 50°C. Emulsions were produced in a Waring blender using a Polytron PT1020 to provide shear.
15.1 g of 40% HMDA was added to the emulsion and the polytron shear was stopped. After 5 minutes, use a blender with gentle shear to blend 91.1g of
NaNO ₃ was dissolved in this suspension. The resulting microcapsules are spherical and 1-10μ in diameter.
It was within the range of Example 16

【table】

[Table] In this example, the reaction temperature was maintained at 50°C.
304.0 g of acetanilide herbicide (93%, industrial grade) containing 21.22 g of PAPI-135 in a Waring blender operating at moderate shear and a Bringman Polytron PT-10 operating at maximum speed.
257.66 g of water containing 6.50 g of Reax 88B sodium lignosulfonate using -20-3500
emulsified inside. Twenty seconds after emulsion formation, 21.22 g of HMDA was added concurrently with shear removal. After 5 minutes, 53.92 g of NaCl was added and dissolved using Waring blender shear. Diameter 4~
Spherical particles in the 10μ range were produced. This formulation was stable over time. Example 17

TABLE Reaction conditions were as in Example 16 except that all reaction components were at room temperature. Most of the uniformly spherical microcapsules were 1-4 microns in diameter. This formulation was stable over time. Example 18

【table】

[Table] The reaction conditions were as in Example 16. Most of the microcapsules were 4-15μ in diameter. This formulation was stable over time. Example 19

[Table] The reaction conditions were as in Example 16, but the starting material was 60
It was warm at ℃. Most of the spherical microcapsules were 4-10 microns in diameter. This formulation was stable over time. Example 20

TABLE Reaction conditions were as in Example 16 except that a Premier disperser and a square stainless steel vessel were used with a Polytron. The size of the spherical microcapsules was 1-10μ. This formulation was stable over time. Example 21

[Table] The reaction conditions were as in Example 16. The spherical microcapsules were 4-10μ in diameter. This formulation was stable over time. Example 22

Table: Reaction conditions were as in Example 16 except that all reaction components were at room temperature. Most of the spherical microcapsules were 4-10 microns in diameter. The formulation was stable over time. Example 23

[Table] All process conditions were as in Example 16. Most of the spherical microcapsules were 4-10 microns in diameter. This formulation was stable over time. Example 24

Table: Process conditions were as in Example 16, but all ingredients were at room temperature. Most of the spherical microcapsules were 4-10 microns in diameter. This formulation was stable over time. Example 25

[Table] Organic acids (2,4-
This is an example of D) microcapsules. This formulation was stable over time. Example 26

【table】

Table: The process conditions were the same as in Example 16 except that this emulsion was made using only a Waring blender operated at higher speed. After adding the diamine, the shear was lowered. Starting material at 60℃
It was hot. This formulation was stable over time. Example 27

Table: All conditions were the same as in Example 25. This formulation was stable over time. No solvent odor was detectable. Example 28

Table: All conditions were the same as in Example 16. This formulation was stable over time. Example 29 Comparing the herbicidal activity of alachlor encapsulated by the method of the invention to unencapsulated alachlor, encapsulated alachlor generally exhibits comparable herbicidal activity against monocotyledonous and broadleaf weeds. The crop safety of encapsulated alachlor was similar to that of unencapsulated alachlor. Microencapsulated alachlor showed greater safety against radiation than non-encapsulated alachlor. The table summarizes the results observed six weeks after application of encapsulated and unencapsulated alachlor in a trial conducted in Brazil with standard agricultural practices at three application rates.

[Table] Example 30 In an aluminum pan measuring 9 1/2" x 5 1/2", pine millet, blueberry, Japanese commonweed, blackberry, and foxtail grass were planted. Alachlor and microencapsulated technical grade alachlor were applied to two pans each in various proportions. Both encapsulated alachlor and unencapsulated alachlor were applied to pans using a belt sprayer with water as the carrier. A visual estimation of % inhibition was performed and recorded two weeks after treatment (2WAT). The bread was dried and the surface vegetation removed. 1/surface from each pan
After removing 2 inches of soil, the pan was replanted and covered with the first top 1/2 inch of soil.
No further herbicide was applied. A second reading was taken two weeks after this second planting. This replanting operation was performed for one additional cycle at rates of 1, 1/2 and 1/4 lb/acre. For the third cycle, 10 ml of standard nutrient solution was added to each loaf to improve fertility. The final observation was made 48 days after the first treatment, or approximately 7 weeks after treatment. The results are summarized in the table. This indicates that microencapsulated alachlor has a longer soil life than non-encapsulated alachlor when given the same proportions. The alachlor used in this example was a commercially available emulsifying concentrate sold by Monsanto under the trade name "Latuso".

【table】

[Table] Example 31 Herbicide activity of microencapsulated trialate and non-encapsulated trialate
A comparison was made of wild oats and cane millet in wheat fields at two locations. The results summarized in the table show that encapsulated trialate exhibits comparable herbicidal activity to unencapsulated trialate against wild oats and sycamore. Encapsulated trialate shows crop safety for wheat as good or even better than non-encapsulated trialate. In the results summarized in the table, aqueous suspensions of microencapsulated trialate and non-encapsulated trialate were applied by spraying by standard agricultural methods.

[Table] Patotrialate

In addition to the above-described advantages of the present invention, herbicide or pesticide microcapsules generally offer several advantages over conventional herbicide or pesticide formulations. Thus, for example, microencapsulated herbicide formulations can reduce mammalian toxicity and prolong herbicide activity. Where herbicide volatility is a concern, microencapsulation may reduce evaporative losses and thus prevent the reduction in herbicide activity associated with such losses. Microencapsulated herbicide formulations can in some cases be less phytotoxic to certain crop plants, thereby enhancing the crop stability of the herbicide. Microencapsulation of herbicides can also protect the herbicide from environmental degradation, reduce leaching of the herbicide into the soil, and extend or increase the soil life of the herbicide. It is appreciated that microencapsulated herbicide formulations have several advantages that make such microencapsulated herbicide formulations a desirable and advantageous alternative to conventional herbicide formulations. I can do it. Accordingly, one object of the present invention is to provide a herbicidal composition consisting essentially of a suspension in water of microcapsules containing herbicide contained within a polyurea encapsulation wall. Herbicides of the above type, preferably acetanilide and thiocarbamate herbicides, and especially alachlor, butachlor, propachlor and trialate, are particularly contemplated for use in such compositions. The concentration of herbicide present in such compositions is about 480 grams per total composition or more, preferably from about 480 to about 700 grams per total composition, and more preferably from about 480 to about 700 grams per total composition. Approximately 600
It is g. Polyurea encapsulation walls are the reaction product of polymethylene polyphenyl isocyanate and polyfunctional amines of the type described above. The concentration of polymethylene polyphenyl isocyanate ranges from about 3.5% to about 21.0% relative to the weight of herbicide present in the composition;
and the concentration of polyfunctional amine ranges from about 1.5% to about 9.0% relative to the weight of herbicide present in the composition. In addition to the microcapsules, there are present in this water a lignin sulfonate emulsifier of the type mentioned above, and optionally formulation ingredients such as antifreeze agents, dispersants, salts, disinfectants, etc. The concentration of lignin sulfonate emulsifier can range from about 1/2 to about 15.0% relative to the weight of herbicide present in the composition. It is to be understood that this invention is not limited to the particular embodiments shown herein, and that it may be embodied in other ways without departing from its spirit.

Claims (1)

[Claims] 1. (a) providing an aqueous phase containing an emulsifying agent selected from the group consisting of lignin sulfonate sodium, potassium, magnesium, calcium or ammonium salts; (b) dissolved in a water-immiscible substance; dispersing a water-immiscible phase consisting essentially of polymethylene polyphenyl isocyanate in said aqueous phase to form a dispersion of water-immiscible phase droplets throughout the aqueous phase; (c) stirring; adding a polyfunctional amine to the dispersion while reacting the amine with the polymethylene polyphenyl isocyanate to form a shell wall of polyurea around the water immiscible material. and the water-immiscible substance is 2-chloro-2',6'-diethyl-N-(methoxymethyl)
Acetanilide, N-(butoxymethyl)-2-chloro-2',6'-diethylacetanilide, 2-chloro-N-isopropylacetanilide, α-chloro-2'-ethyl-6'-methyl-N-(1- Methyl-2-methoxyethyl)acetanilide, α-
Chloro-N-(2-methoxy-6-methylphenyl)-N-(1-methylethoxymethyl)acetamide, α-chloro-N-methyl-N-[2-methyl-6-(3-methylbutoxy)phenyl] Acetamide, α-chloro-N-[2-methyl-6-
(2-Methylpropoxy)phenyl]-N-(propoxymethyl)acetamide, N-[(acetylamino)methyl]-α-chloro-N-(2,6-diethylphenyl)acetamide, α-chloro-N-
Methyl-N-(2-methyl-6-propoxyphenyl)acetamide, N-(2-butoxy-6-
methylphenyl)-α-chloro-N-methylacetamide, (2,4-dichlorophenoxy)acetic acid isobutyl ester, 2-chloro-N-(ethoxymethyl)-6'-ethyl-o-acetatoluidide, 1-( 1-cyclohexen-1-yl)-3-
(2-fluorophenyl)-1-methylurea, S-
2,3,3-Trichloroallyl-diisopropylthiocarbamate, S-2,3-dichloroallyl-diisopropylthiocarbamate, α,α,α
-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine, 2-chloro-4-ethylamino-6-isopropylamino-1,3,
5-triazine, 2-chloro-4,6-bis(ethylamino)-1,3,5-triazine, 2-chloro-4,6-bis(isopropylamino)-1,
3,5-triazine, 4-amino-6-(1,1
-dimethylethyl)-3-(methylthio)-1,2,
4-triazin-5(4H)one, N'-(3,4-
dichlorophenyl)-N-methoxy-N-methylurea, 2-chloro-N-(ethoxymethyl)-N-
[2-Methyl-6-(trifluoromethyl)phenyl]acetamide, α-chloro-N-(ethoxymethyl)-N-[2-ethyl-6-(trifluoromethyl)phenyl]acetamide, methyl and ethyl parathion, selected from the group consisting of ethyl 2-chloro-4-(trifluoromethyl)-5-thiazolecarboxylate and benzyl 2-chloro-4-(trifluoromethyl)-5-thiazolecarboxylate. A method for encapsulating water-immiscible substances within a polyurea shell wall. 2 The concentration of the water-immiscible substance per composition
480-700 g. The method of claim 1. 3. the concentration of polymethylene polyphenyl isocyanate is from 3.5 to 21.0% by weight of the water-immiscible material, the concentration of the polyfunctional amine is from about 1.5 to about 9% by weight of the water-immiscible material, and 3. The method of claim 2, wherein the concentration of the emulsifier is between 1/2 and 15% by weight of the water-immiscible substance. 4 The concentration of the water-immiscible substance is per composition.
480 to 600 g, and the concentration of polymethylene polyphenyl isocyanate is 5.0 g of the water-immiscible substance.
~15.0% by weight, and the concentration of the polyfunctional amine is between 2.0 and 7.5% by weight of the water-immiscible material;
and the concentration of the emulsifier is the water-immiscible substance.
Claim 3, which is 2.0 to 6.0% by weight.
The method described in section. 5 The concentration of polymethylene polyphenyl isocyanate is 7.0 relative to the weight of said water-immiscible material.
%, the concentration of the polyfunctional amine is 3.0% relative to the weight of the water-immiscible material, and the concentration of the emulsifier is 2.0% relative to the weight of the water-immiscible material. , the fourth claim
The method described in section. 6. The method according to any one of claims 1 to 5, wherein the emulsifier is a sodium salt of lignin sulfonate. 7. The method of claim 6, wherein the amine is 1,6-hexamethylene diamine. 8. The reaction temperature is higher than the melting point of the water-immiscible substance,
The method according to claim 1, wherein the temperature is maintained at 80°C or lower. 9 The average particle size of microcapsules is 1μ in diameter.
5. A method as claimed in claim 1, in the range of ~50μ. 10 The water-immiscible substance is α-chloro-2′-ethyl-6′-methyl-N-(1-methyl-2-methoxyethyl)acetanilide, α-chloro-N-
(2-methoxy-6-methylphenyl)-N-(1
-methylethoxymethyl)acetamide, α-chloro-N-(ethoxymethyl)-N-[2-methyl-6-(trifluoromethyl)phenyl]acetamide, α-chloro-N-(ethoxymethyl)-N
-[2-ethyl-6-(trifluoromethyl)phenyl]acetamide and N-[(acetylamino)methyl]-α-chloro-N-(2,6-diethylphenyl)acetamide. The method described in scope item 7. 11 The water-immiscible substance is α-chloro-N-
11. The method of claim 10, wherein (ethoxymethyl)-N-[2-methyl-6-(trifluoromethyl)phenyl]acetamide. 12. The method of claim 10, wherein the water-immiscible substance is α-chloro-2'-ethyl-6'-methyl-N-(1-methyl-2-methoxyethyl)acetanilide. 13. The method of claim 10, wherein the water-immiscible substance is N-[(acetylamino)methyl]-α-chloro-N-(2,6-diethylphenyl)acetamide. 14 The water-immiscible substance is a mixture of S-2,3,3-trichloroallyl-diisopropylthiocarbamate and α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine 11. The method of claim 10. 15 The water-immiscible substance is α-chloro-2′,
6'-diethyl-N-methoxymethylacetanilide and 4-amino-6-(1,1-dimethylethyl)
-3-(methylthio)-1,2,4-triazine-
11. The method of claim 10, wherein the method is in a mixture with 5(4H)one. 16 The water-immiscible substance is α-chloro-2′,
11. The method of claim 10, which is a mixture of 6'-diethyl-N-methoxymethylacetanilide and N'-(3,4-dichlorophenyl)-N-methoxy-N-methylurea. 17 The water-immiscible substance is α-chloro-2′,
11. The method of claim 10, wherein the mixture is a mixture of 6'-diethyl-N-methoxymethylacetanilide and 2-chloro-4-ethylamino-6-isopropylamino-1,3,5-triazine. 18 The water-immiscible substance is α-chloro-N-isopropylacetanilide and 2-chloro-4
-ethylamino-6-isopropylamino-1,
11. A method according to claim 10, which is a mixture with 3,5-triazine. 19 The water-immiscible substance is α-chloro-N-
(Ethoxymethyl)-N-[2-methyl-6-(trifluoromethyl)phenyl]acetamide and 2-
11. The method according to claim 10, which is a mixture with chloro-4-ethylamino-6-isopropylamino-1,3,5-triazine. 20 The water-immiscible substance is 2'-methyl-6'-ethyl-N-(1-methoxyprop-2-yl)-2
-Chloroacetanilide and 2-chloro-4-ethylamino-6-isopropylamino-1,3,5
- a mixture with triazine.