MXPA99008946A - Encapsulation process and encapsulated products - Google Patents

Abstract

A process for encapsulating a partially water-miscible organic material within a polyurea or polyurethane shell is provided utilizing a water-soluble tertiary amine in the reaction dispersion. Microcapsules and methods of using microcapsules are also provided.

Description

. * ._ ENCAPSULATION PROCESS AND ENCAPSULATED PRODUCTS FIELD OF THE INVENTION: This invention relates to a process for the encapsulation of materials that are partially miscible in water. An application of the invention involves the encapsulation of materials that will modify the behavior of animal species, for example semiochemicals such as pheromones, and their use for the control of pests in forestry, agriculture or horticulture.

BACKGROUND OF THE INVENTION The use of interfacial condensation to encapsulate substances such as pharmaceuticals, pesticides and herbicides is discussed in U.S. Patent No. 3,577,515, filed May 4, 1971. The encapsulation process involves two liquid phases. immiscible, one that is dispersed in the other by agitation, and the subsequent polymerization of the monomers of each phase at the interface between the volumetric (continuous) phase, and the dispersed droplets. Immiscible liquids are typically water and an organic solvent. Polyurethanes and polyureas are included in the types of materials suitable for producing the microcapsules. The use of emulsifying agents (also known as REF: 31305 suspension or dispersion agents) is also discussed. The United States Patent describes the formation of microcapsules comprising a polymeric sphere and a liquid center, in the range of 30 micrometers to 2 mm in diameter, depending on the monomers and solvents used. United Kingdom Patent No. 1,371,179 describes the preparation of polyurea capsules to contain colorants, inks, chemical reagents, pharmaceuticals, flavoring materials, fungicides, bactericides, and pesticides such as herbicides and insecticides. The capsules are prepared from various di- and polyisocyanates in a dispersed organic phase. Some of the isocyanates present react to produce an amine that further reacts with the remaining isocyanate at the interface with water and subsequently polymerizes to form a polyurea layer. The aqueous phase also contains a surfactant, for example an ethoxylated nonylphenol or a polyethylene glycol ether of a linear alcohol. In addition, the aqueous phase contains protective colloids, typically polyacrylates, methylcellulose and PVA. Particle sizes as small as 1 micrometer are exemplified. The encapsulation of insect hormones and their imitations are among the mentioned systems.

U.S. Patent No. 4,046,741 and U.S. Patent No. 4,140,516 appear to refer to the developments of the process described in U.S. Patent No. 1,371,179. In accordance with U.S. Patent No. 4,046,741, a problem with microcapsules is the instability caused by the evolution of carbon dioxide from the residual isocyanate trapped in the microcapsules. U.S. Patent No. 4,046,741 describes a subsequent treatment of the polyurea microcapsules with ammonia or an amine such as diethylamine. This removes the residual isocyanate, allowing the subsequent storage of the microcapsules at lower pH without the generation of carbon dioxide. U.S. Patent No. 4,140,516 discloses the use of quaternary salts as phase transfer catalysts to accelerate the formation of polyurea microcapsules. U.S. Patent No. 4,417,916 describes the encapsulation of water-immiscible materials, such as herbi-acids in a polyurea layer. A polyisocyanate and a polyamine are used to form the polyurea, and the invention appears to reside in the use of a lignin sulfonate compound as an emulsifier in the polyurea formation reaction. The concentration range of the water-immiscible material encapsulated in the listed examples is 320 and 520 g / L of composition.

U.S. Patent No. 4,563212 is similar in teaching to U.S. Patent No. 4,417,916, but uses emulsifiers other than lignin sulfonates, particularly fused sulphonated naphthalene formaldehyde condensates and sulfonated polyesters. European Patent No. 611-253 describes the reaction of polyisocyanates and polyamines to encapsulate materials, such as pesticides in polyurea, using nonionic surfactants which are block copolymers containing hydrophilic blocks together with hydrophobic blocks. Canadian Patent No. 1,044,134 relates to the microencapsulation of insecticides, in particular pyrethroids. The insecticide is dissolved, together with a polyisocyanate, in an organic solvent immiscible with water. The solution is then dispersed in the organic solvent in water by stirring, and a polyfunctional amine is added while stirring is continued. The polyisocyanate and the polyfunctional amine react to form a wall of the polyurea layer surrounding the dispersed droplets containing the insecticide. Canadian Patent No. 1,179,682 discusses the encapsulation of pheromones. Microcapsules containing pheromones are produced from toluene diisocyanate and ethylene diamine and / or diethylene triamine. In a described embodiment, a polyamine in the form of a salt is added to an isocyanate dispersion, to allow the polymerization to be initiated by the addition of a base. It is said that this could improve the stabilization of behavior modifying compounds that are aldehydes, but this is not exemplified. Canadian Patent No. 1,179,682 states that pheromones are photolabile and lose effectiveness after exposure to sunlight. A tertiary phenylene diamine is used as a light stabilizer, and is added with the phase immiscible with water, so that it is finally encapsulated with the pheromone.

BRIEF DESCRIPTION OF THE INVENTION In one aspect, the present invention provides a process for encapsulating an organic material partially miscible with water within a polyurea or polyurethane layer, the process comprising: (a) providing an aqueous phase containing a surfactant; (b) dispersing in the aqueous phase a water-immiscible organic solvent in which the partially miscible material in water to be encapsulated and a polyisocyanate are dissolved or dispersed, to form a droplet dispersion of the organic solvent in the continuous aqueous phase; (c) adding a water-soluble tertiary amine to the dispersion; (d) subsequently, adding to the dispersion a polyfunctional compound containing the functional groups selected from the group consisting of primary amine, secondary amine and hydroxy groups, whereby discrete capsules are formed composed of the encapsulated material in a polyurea layer or polyurethane.

In another aspect, the invention provides microcapsules composed of a material encapsulated within a layer of polyurea or polyurethane, these microcapsules contain a tertiary amine soluble in water. In a preferred embodiment, the encapsulated material is a material partially miscible with water and the amount of the partially miscible material in encapsulated water is at least 5%, preferably at least 9%, based on the total weight of the microcapsules. In another aspect, the invention provides microcapsules composed of a partially water miscible organic material of higher molecular weight of about 100 and less than about 400 and containing at least one heteroatom, encapsulated within a polyurea or polyurethane layer, the amount of the Encapsulated material is at least 5%, preferably at least 9%, based on the total weight of the microcapsules.

DESCRIPTION OF THE PREFERRED MODALITIES The invention relates particularly, but not exclusively, to the encapsulation of partially water-miscible organic molecules of compounds having a molecular weight in the range of about 100 to about 400, especially about 150 to 300. The compounds contain a heteroatom that confers a certain degree of miscibility in water. For many of the compounds of interest, the only heteroatom is oxygen, and there could be up to three heteroatoms per molecule in, for example, carboxylic acids substituted by hydroxy or substituted by keto. Of course, the unsubstituted carboxylic acids contain two oxygen atoms and simple aldehydes, the ketones and the ethers contain only one oxygen atom. However, compounds containing nitrogen and / or sulfur atoms are also of interest. The compounds are gradually released from the microcapsules with the passage of time. This contrasts with the microcapsules that release the active ingredient once, when the microcapsule layer is broken. The encapsulated compounds could be aldehydes, alcohols, epoxy compounds, ethers, ketones, especially reactive ketones in which the double bond of the carbonyl group is conjugated with one or more double bonds, for example, acetophenone wherein the carbonyl group is conjugated with the double bonds of the aromatic ring. Of particular interest are biologically active compounds. For the purposes of the present invention, the term "Biologically active" means materials that affect the life processes of organisms. Materials that are biologically active include herbicides, pesticides, pharmaceuticals and semiochemicals, which include naturally and artificially produced pheromones. The materials of this nature that are of particular interest, are those materials that interfere with a life process essential for the survival of a white plague. Pheromones could be defined as compounds that, when produced naturally, are secreted by a member of an animal species that can influence the behavior or development of another member of the same animal species. Pheromones are specific for each species and, therefore, the application of pheromones for the modification of insect behavior has minimal effect on white pests. The pheromones supplied for the modification of insect behavior interfere with the "couple encounter process" by releasing point sources of pheromone, which could compete with or camouflage the pheromone feather of a female. This last type of action differs from chemical insecticides or regulators or insect growth hormones, in that pheromones are the target of future generations of insects, not the current ones. As pheromones are very specific for a species and are used only in small quantities, their use is more environmentally acceptable than the diffusion of pesticides. It is known that the use of pheromones interferes with the mating of insects, for example, the impregnation of hollow fibers, the flakes of plastic laminates or knots braided with a pheromone and then physically bind the fibers or knots to the plants that are going to protect from insect infestation. This process is labor intensive and is adequate to protect small areas, such as orchards, but it is inadequate to protect large areas of forest. The cost of labor would not only be prohibitive, but would also be impossible to cover a large area of forest within the span created by the mating season of a white insect. To cover large areas, you can resort to using the spray area. For spraying, in particular aerial spraying, it is desirable or essential that the microcapsules have certain characteristics. Ideally, they remain suspended in water, so if they are kept in suspension in tanks on an airplane they do not cause difficulty. If the microcapsules are not kept in suspension, there is a possibility that they are immersed in the suspension and coagulate and, while this can be avoided, at least some degree of agitation, the need to provide agitation constitutes another disadvantage. To atomize the suspension when sprayed, the suspension is forced through two perforated rotating disks that are immediately upstream of the discharge nozzle. To minimize damage as the microcapsules pass through the discs, it is desirable that they exhibit a degree of elasticity. Due to the handling to which the microcapsules are subjected, and to the desired slow release over time of the encapsulated material, it is desirable that the layer of the microcapsules of the present invention should be quite elastic, and not brittle. The present invention provides microcapsules suitable for this purpose.

Compounds of interest at the lower end of the above molecular weight range include mercaptans. Some compounds mark the territory by means of urine, to discourage the entry of other animals into this territory. Examples of such animals include game animals such as wolves, lions, dogs, etc. The ingredients in the urine of such animals include mercaptans. By dispersing the microcapsules containing the appropriate mercaptans it is possible to define a territory and discourage the entry of certain animals in particular in such territory. For example, the urine of a wolf includes a mercaptan and, the distribution of microcapsules from which this mercaptan is gradually released to define a territory, will discourage deer to enter this territory. Other materials that can be encapsulated and used to discourage the approach of animals include garlic essences, rotten eggs, and capsaicin. Other compounds that can be included in the microcapsules of the invention include perfumes, fragrances, flavoring agents and the like. The invention is particularly useful for encapsulating materials that are partially miscible in water. While the limits of what is meant by "partially miscible" are not precise, in general a substance that is immiscible in water is considered if its solubility in water is less than about 0.5% by weight. It is considered to be soluble in water if its solubility is greater than 98%, that is, if 1 gram of the substance is placed in 100 grams of water, 0.98 grams will be dissolved. A substance whose solubility falls between these approximate limits is considered to be partially miscible in water. The invention relates, in particular, to the encapsulation of partially miscible alcohols in water, aldehydes, carboxylic acids, ketones, ethers including epoxy compounds and mercaptans. In the past it has been difficult to achieve high degrees of encapsulation of materials that have some degree of solubility in water, since the material is fragmented between the small amount of organic solvent and the relatively greater amount of water that constitutes the continuous phase. In addition, these compounds can be expected to react with the reagents used to encapsulate. The aldehydes and the ketones react with amines to form aldimines and ketimines, respectively. The alcohols, carboxylic acids and mercaptans react with isocyanates. The epoxy compounds react with the amines and with isocyanates. Therefore, it is surprising that, with the addition of a tertiary amine according to the invention, these materials can be encapsulated with the formation of discrete capsules. Preferred embodiments of the invention are described in connection with the encapsulation of partially miscible pheromones in water, however, it should be appreciated that the invention extends to the encapsulation of materials other than such pheromones and to microcapsules containing such materials other than the pheromones. These materials may or may not be biologically active. Pheromones can be broadly classified in terms of solubility in water, either as insoluble, that is, immiscible or partially miscible in water. Many pheromones have, for example, an ether terminal group, and the acetate or format group and, in general, they are immiscible in water and the incorporation of these into the microcapsules by the known methods does not present any particular problem. Many other pheromones have an aldehyde terminal group or an alcohol, and in general, these are partially miscible in water and potentially reactive with the reagents used to encapsulate. By means of the invention, it is possible to encapsulate partially water-soluble pheromones in the improved amount and with longer effective life, as compared to Canadian Patent No. 1,179,682. This is particularly remarkable according to Patent No. 1, 179,682 which demonstrates only the encapsulation of acetate-terminated pheromones that are immiscible in water and whose encapsulation presents no difficulties due to partial solubility in water, nor does difficulty due to reactivity, since the esters are not reactive with isocyanates or the amines. The range of average particle size, demonstrated in the Canadian Patent is 1-5 microns. The microcapsules produced tend to submerge to the bottom of the reaction vessel and form a clot. Another disadvantage of this system is that the pheromone appears to be encapsulated only in a small amount. Example 4 is the only example that really shows the encapsulation. The encapsulated pheromones are water-immiscible acetate compounds that are present in the original reaction mixture in an amount of 4% w / v. The amount actually incorporated into the microcapsules in the product is not expressed. Pheromones such as (Z) -9-tetradecenyl acetate (Z9-TDA) are used and all the formulations exemplified in this patent contain 2 or 3 co-encapsulated pheromones. The half-lives of the pheromones in the microcapsules sprayed during the "maximum limit" studies are typically greater than 20 days when the light stabilizer is present. However, the half-lives of the stabilized pheromones during the "field" studies on the sprayed microcapsules fall from 0.4 to 8.5 days, depending on the chemistry of the pheromone and the thickness of the microcapsule wall. It will be appreciated that the encapsulation process of the invention does not have the effect of rendering the encapsulated material inert or ineffective as a pheromone. The encapsulation material has a certain degree of elasticity, so that the microcapsules will withstand the harsh mechanical conditions at the which could be subjected to aerial spraying, and a certain degree of porosity so that the encapsulated material is slowly released over time, for example a pheromone is released slowly during the mating season of a white insect.

The process of the present invention provides an improved encapsulation of the material to be encapsulated. The following examples show the encapsulation of the partially miscible pheromone in water of 9% w / v. The microcapsules produced are typically 10-100 micrometers, discrete, and will remain in suspension in water. Encapsulated pheromones have a superior performance in preventing the growth of the insect population when they are administered in the form of a spray from a predetermined height. The spraying process is safe, quick, less likely to contaminate groundwater, results in lower exposure to the environment and other non-target species and, in general, has lower labor costs. In this way, the improved microcapsules, combined with the release process, have resulted in improved development over existing methods such as hollow fibers, plastic laminates and braided knots. The encapsulated pheromones are preferably insect pheromones. In the notation that is used later to describe the structure of the pheromones, first the type (E or Z) is given and the position of the double bond or bonds, is given after the number of carbon atoms in the chain and, for The nature of the terminal group is provided. For the purpose of illustration, pheromone Z-10 of aldehyde C19 has the structure: In fact, pheromones could be mixtures of compounds in which a component of the mixture predominates, or at least be a significant component. Mention is made as examples of significant or predominant partially water-miscible components of insect pheromones, with white species in parentheses, which are detailed below: aldehyde C14 E / Z-ll (Eastern Spruce Yolk Worm), aldehyde C19 Z-10 (Yellow Cup Spruce Saw Fly), C14 Z-ll alcohol (Larva Crinkling Oblique Strip Sheets), C12 Z-8 Alcohol (Oriental Fruit Moth) and C12 Alcohol E, E -8,10 (Apple Moth). An example of a ketone that is a pheromone is 7-tetradecen-2-one E or Z, which is effective with the oriental moth. An ether that is not a pheromone but is valuable is the -alilanisol, which can be used to make pines not attractive to the southern pine moth. As stated above, a tertiary amine is added to the aqueous phase containing the pheromone, the surfactant and the polyisocyanate. The tertiary amine is introduced after the addition of the immiscible solvent in water containing the pheromone and the polyisocyanate. A period of time should elapse during which the tertiary amine is in contact with the polyisocyanate and before adding the polyfunctional compound, for example the polyfunctional amine. Conveniently, in the laboratory scale when quantities in grams are used, the period is at least about two minutes, preferably at least about 5 minutes. The optimal period may depend on the scale of reaction, but may be determined by experimentation. The tertiary amine, in the amount used, must be freely soluble in the water present in the reaction mixture. The simplest tertiary amine is trimethylamine and this compound can be used, and its homologs C2, C3 and C4. Of course, it is also possible to use tertiary amines containing a mixture of alkyl groups, for example methyldiethyl amine. The tertiary amine may contain more than one tertiary amine radical. It could also contain other functional groups with the proviso that these other functional groups do not interfere with the required reaction or with the functional groups that participate beneficially in the required reaction. As an example of a functional group that does not interfere, an ether group can be mentioned. As examples of beneficently involved groups, the primary and secondary amine groups are mentioned, which will form urea radicals with the isocyanate groups, and the hydroxyl groups, which will form urethane radicals with the isocyanate groups. Examples of suie tertiary amines include compounds having the following structures: N [CH2 (CH2) r? CH3] 3, where n e s 0, 1, 2 or 3 Of the tertiary amines, the one that is preferred is triethylamine (TEA). The amount of tertiary amine needed is not very large. It is conveniently added in the form of a solution containing 0.5 g of TEA per 10 mL of water. Usually, 0.5% by weight of this solution is sufficient, based on the total weight, although in some cases 0.7% may be required. Usually the amount used does not exceed 1%, although no disadvantages arise if more than 1% is used. A surfactant is required for the aqueous dispersion. Preferably, this is a non-ionic surfactant. As examples of suitable surfactants, polyvinylpyrrolidone (PVP), polyvinyl alcohol (PVA) and poly (ethoxy) nonylphenol are mentioned. PVP is available in various molecular weights in the range of about 20,000 to about 90,000 and all of them may be used, but the molecular weight PVP of about 40,000 is preferred. The poly (ethoxy) nonylphenols are available under the trademark Igepal, with various molecular weights depending on the length of the ethoxy chain. The poly (ethoxy) nonylphenols of the formula can be used: wherein n has an average value of about 9 to about 13, but poly (ethoxy) nonylphenol Igepal 630, which indicates a molecular weight of about 630 is preferred. Other examples of surfactants include polyether block copolymers such as, Pluronic ™ and Tetranic ™, polyoxyethylene adducts of fatty alcohols such as, Brij ™ surfactants and fatty acid esters, such as stearates, oleates and the like. Examples of such fatty acids include sorbitan monostearate, sorbitan monooleate, sorbitan sesquioleate and the like. Examples of the alcohol moieties of the fatty esters include glycerol, glycosyl and the like. Fatty esters are commercially available as Arlacel C® surfactants. The surfactants vary in their surfactant properties, and the surfactant properties affect the size of the microcapsules formed. Likewise, the use of molecular weight PVP of 40,000 will give larger microcapsules than Igepal 630. The surfactant used, and also the degree and level of agitation, affect the size of the obtained microcapsules. In general, they could be from approximately 1 to approximately 100 meters in size, depending on the conditions employed. However, for the encapsulation and slow release of pheromones, it is preferred that the microcapsules have a size of at least about 10 to about 60 microns and, in particular, microcapsules in the range of about 20 to about 30 are especially preferred. micrometers although less preferred, ionic surfactants can be used. Mention is made of the partially neutralized salts of the polyacrylic acids, such as sodium or potassium polyacrylate or sodium or potassium polymethacrylate. Preferably, the dispersion of the organic phase is carried out by stirring. Preferably, the stirring is decreased before the addition of the polyfunctional amine to the reaction mixture. Typical initial stirring rates are about 500 rpm and about 2,000 rpm preferably, from about 1,000 rpm to about 1,200 rpm. As stated above, the diameter of the microcapsules produced in this invention is preferably from about 1 micrometer to about 60 micrometers, preferably from 20 to 30 micrometers. The precise adjustment of the diameter is achieved by controlling the agitation of the reaction mixture. The polyisocyanate could be aromatic or aliphatic and could contain two, three or more isocyanate groups. Some examples of aromatic polyisocyanates include 2,4- and 2,6-toluene diisocyanate, naphthalene diisocyanate, diphenylmethane diisocyanate and triphenylmethane-p, p ', p "-trifyl triisocyanate The aliphatic polyisocyanates could be selected from aliphatic polyisocyanates that contain two isocyanate functionalities, three isocyanate functionalities or more than three isocyanate functionalities, or mixture of these polyisocyanates. Preferably, the aliphatic polyisocyanate contains from five to thirty carbons more preferably, the aliphatic polyisocyanate comprises one or more cycloalkyl radicals. Examples of the preferred isocyanates include dicycloexylme t an-4, 4'-diisocyanate; 1,6-hexamethylene diisocyanate; isophorone diisocyanate; trimethyl-hexamethylene diisocyanate; 1, 6-hexamethylene diisocyanate trimer; isophorone diisocyanate trimer; 1,4-cyclohexane diisocyanate; 1, 4 - (dimethylisocyanate) cyclohexane; hexamethylene diisocyanate biuret; hexamethylene diisocyanate urea; trimethylene diisocyanate; 1, 2, propylene diisocyanate and 1,2-butylene butylene diisocyanate. Mixtures of polyisocyanates can be used. Particularly preferred polyisocyanates are the poly ethylene polyphenylisocyanates of the formula:wherein n is 2 to 4. These compounds are available under the trademark Mondur-MRS. The mol equivalent ratio of the functionality of the total primary amine to the isocyanate functionality in the system is preferably from about 0.8: 1 to 1: 1.2, and more preferably about 1: 1.1. The polyfunctional compound containing the amine and / or hydroxy functional groups contains at least two functional groups which are selected from primary amine, secondary amine and hydroxy groups and, should be soluble in water. Examples of suitable compounds include ethylenediamine and diethylenetriamine and the compounds of the general formula: R R R H (CH2CHN) mH where m takes a value from 1 to 8, and each R is independently, hydrogen or methyl. Also useful are compounds whose structure is similar to that of the above formula, but have one or more oxygen atoms present in the ether bonds between the carbon atoms. It is preferred that R is hydrogen, especially at the terminal amino groups. Aromatic diamines, for example t-oluenediamine, can be used. Mixtures of polyfunctional compounds can be used. Mention is made of tetraethylenepentamine (TEPA); and pentamethylenehexamine, of which TEPA is preferred. As the solvent immiscible with water, a non-polar solvent is used which is inert to the encapsulation reaction, but in which the polyisocyanate and the material to be encapsulated can be dissolved or suspended. Suitable solvents are hydrocarbon solvents, for example kerosene, and alkylbenzenes such as toluene, xylene and the like. It is desirable to employ only a small amount of the solvent; amounts of up to about 5% based on the amount of water, usually sufficient and in most cases it is preferred to use the solvent in an amount of about 3% or less. The reaction proceeds easily at room temperature, but it may be advantageous to operate at a temperature below room temperature, below about 0 ° C, preferably at about 15 ° C. In a preferred embodiment, the product of the microencapsulation process is a plurality of microcapsules having a size in the range of about 10 to about 60 microns, more preferably about 20 to about 30 microns, and an encapsulated pheromone contained within the polyurea layer or polyurea / polyurethane. The capsules will remain suspended in water, that is, they have a specific weight less than 1 and, the layer has elasticity and at the same time porosity to allow the slow release of the encapsulated pheromone. The microcapsules can be suspended in water to give a suitable suspension for aerial spraying. The spray could contain a suspending agent, for example a rubber suspending agent, such as guar gum, ramsan gum and xanthan. It has not been considered to include a light stabilizer to protect the encapsulated pheromone. However, the incorporation of a light stabilizer, if needed, is within the scope of the invention. Suitable light stabilizers include the tertiary phenylenediamine compounds that are set forth in Canadian Patent No. 1,179,682, the disclosure of which is incorporated by reference. The light stabilizer can be incorporated by dissolving it, with the pheromone and the polyisocyanate, in the solvent immiscible with water. Alternatively, a light stabilizer may be incorporated into the polyurea layer as shown in Canadian Patent No. 1,044,134, the disclosure of which is also incorporated herein by reference. To assist in the determination of the distribution of the pulverized microcapsules, it is possible to include a colorant in the microcapsules. The dye should be soluble in oil and can be incorporated, with the pheromone and the polyisocyanate, into the solvent soluble in water. Alternative or, additionally, soluble or dispersible in oil, can be included in the aqueous suspension or the microcapsules, where it is absorbed by the layer of the microcapsule. Suitable oil soluble or dispersible dyes can be obtained from DayGlo Color Corporation, Cleveland, Ohio and include Blaze Orange, Saturn Yellow, Aurora Pink and the like. Although the invention has been described extensively with reference to the encapsulation of partially miscible pheromones in water, other molecules that are active in nature can be encapsulated in a similar manner. As examples, linalool, terpineol, fenone and keto-decenoic acids and hydroxy-decenoic acids, which promote the activity of worker bees, are mentioned. The encapsulated 4-allylanisole can be used to make the pines unattractive to southern pine beetles. The 7,8-epoxy-2-methyl-octadecane can be used to combat the religious moth or the gypsy moth. Flavors and natural fragrances can be encapsulated. All of these applications, and the microcapsuals containing these materials, are within the scope of the present invention. The following non-limiting examples are provided to more particularly illustrate the present invention.

Pheromones Partially Miscible in Water Example 1 Tretradecanal (TD) (1 g) and toluene (3 g) were mixed with polymethylene polyphenylisocyanate (Mondur-MRS *) (4 g). The mixture was added to a 500 mL glass reactor containing deionized water (DI) (100 mL) and PVP of molecular weight of approximately 40,000 (1 g). The solution was stirred at 1000 rpm for 5 minutes, then a small amount of dilute aqueous TEA (0.5 g / 10 mL of water) was added. After 5 minutes, the stirring was reduced to approximately 800 rpm for the slow addition of TEPA (50 g of a 5% aqueous solution). Stirring was continued for 4 hours, then stirring was stopped. Discrete spherical microcapsules with a particle size range of 10 to 100 microns were produced.

Example 2 The procedure described in Example 1 was used, except that p-xylene was used as the diluent in place of toluene. TD (5 g) was mixed with Mondur-MRS * (10 g) and p-xylene (15 g). The mixture was added in DI water (200 mL) containing PVP (2 g). The dispersed organic phase with a stirring speed of 1000 rpm. TEA was added (0.5 g in water) for 5 minutes. After about 5 additional minutes, TEPA (50 g of the 5% aqueous solution) was added dropwise while the reaction mixture was stirred at about 800 rpm. The reaction mixture was stirred for 4 hours. The discrete microcapsules of 10 to 90 mm were obtained. These microcapsules remained suspended in water.

Example 3 Decyl aldehyde (DA) (1 g), Mondur-MRS were added (4 g) (a registered trademark of Bayer Company) and toluene (3 g) in a 500 mL glass reactor, containing PVP (1 g) and DI water (100 L). The mixture was stirred at a speed of 1200 rpm for a period of one minute. TEA (0.5 g) was diluted with DI water (15 mL) and the solution was added to the reactor. After about 5 additional minutes, TEPA (38 g, 5% aqueous solution) was added dropwise. The reaction was stirred at 1200 rpm for an additional 10 minutes. The stirring speed was then lowered to 800 rpm for 2 hours, then reduced to 500 rpm for 2 hours. During the course of the reaction, discrete capsules were formed. The capsules were in the size range of 10 to 100 mm.

Comparative Example A This example is comparative and illustrates an attempt to prepare the DA microcapsules in the absence of a tertiary amine. DA (1 g), Mondur-MRS * (4 g) and toluene (3 g) were added in a mixture of PVP (1 g) and DI water (100 mL) in a 500 mL glass reactor. The solution was stirred at 1200 rpm for 2 minutes. TEPA (5% aqueous solution) was measured in the reactor while stirring at approximately 800 rpm. Coagulation was observed after the addition of 5 mL of the TEPA solution. In total, 15 g of TEPA solution was added and the reaction was allowed to proceed for 2 hours. The product was isolated in the form of clot.

Example 4 The procedure set forth in Comparative Example A was adopted, but TEA was used as the tertiary amine, TD was used in place of DA, - xylene was used in place of toluene and the ratio of TD to inert diluent was changed from 1 to 2. : 3 to 1: 9. TD (3 g) and p-xylene (27 g) were mixed with Mondur-MRS * 8 g). The mixture was then added in DI water (150 mL) containing PVP (2 g) in a glass reactor. The reagents were mixed at 1000 rpm to produce a uniform suspension. While the mixture was stirred at approximately 800 rpm, TEA (0.5 g in 10 mL) was added. TEPA (12 g) was then added in DI water (38 mL). Stirring was continued for 3 hours. The resulting discrete capsules were characterized by the optical microscope and were found in the particle size range from 20 to 100 microns. The capsules were kept suspended in water.

Example 5 PVP (1 g) in water (325 g) was added in a 1 L glass reactor. Zl 0 - nonadecenal (45 g) and p-xylene (15 g) were mixed with Mondur MS (6 g) which it was then added to the reactor under stirring at 1800 rpm. After two minutes, TEA (0.5 g in 5 mL of water) was added dropwise, followed by the dropwise addition of TEPA (4 g in 20 mL of water). The reaction was continued for 40 minutes after the final addition of TEPA under agitation about 1000 rpm. Then, the mixture of 1.5 g of ramsan gum, 2 g of proxel (1, 2-benzisothiazolin-3-one, a preservative, and 0.2 g of Igepal CO-630 emulsifier in 50 g of water, was introduced into the The microcapsules were found in the range from 5 to 40 micrometers The product analysis revealed that the microcapsules constituted 16% by weight of the reaction product, and the encapsulated Z-10-nonadecenal constituted 9.47% by weight of the product. E / Z-11-tetradecenal compound was incorporated into the discrete microcapsules using the procedure of Example 5.

Example 6 PVP (11 g) was dissolved in 3490 g of water in an 8 L size reactor. An oil phase containing Z-10-nonadecenal (479 g), p-xylene (159 g) and Mondur MS (64 g) was added to the reactor under stirring at 1800 rpm. TEA (2 g in 50 g of water) was added to begin the polymerization, followed by the addition of TEPA (42 g in 200 g of water) at the rate of 3 mL / min. After the final addition of TEPA, the suspension was stirred at 1000 rpm for 40 min. A mixture of ramsan gum (16 g), proxel (20 g) and Igepal CO-630 (2 g) in 500 g of water was added to the reactor, and mixed well with the capsule suspension. The product analysis revealed a solid content of 16%, which contained 9.51% of encapsulated Z-l O-nonadecenal (based on the total).

Example 7 PVP (10 g) was dissolved in DI water (4.2 L) in an 8L reactor, and the mixture was stirred at 1400 rpm. E-11-tet radecen-1-ol (500 mg) was dissolved in p-xylene (160 g); isophorone diisocyanate (IPDI) (84.8 g) was added to this solution and the mixture was added to the reactor at a stirring speed of 1200 rpm. TEA (1 g) was diluted with DI water (20 ml) and the solution was added to the reactor at a stirring speed of 1700 rpm. After five minutes, TEPA (40 g) was added in water (80 ml) at a rate of 3 ml per minute. After completing the TEPA addition, the suspension was stirred at 1650 rpm for 30 minutes. The discrete microcapsules of 10 to 80 microns were obtained. The following alcohols were incorporated into the discrete microcapsules by the procedure of Example 7: alcohol C14 Z-ll alcohol C12 Z-8 alcohol C12 E, E-8, 10 Performance of the Pheromone Formulation To control the physical performance of the aerial application, two parameters were measured: (1) air concentrations of the pheromone released from the microencapsulated formulation and (2) the amount of the formulation that remained in the foliage during the course of time.

Methods for the E / Z-11-tetradecenal A site of approximately 5 ha (mixed balsamic fir, maple and black fir) was selected for the aerial application (-100 g / ha) of the microencapsulated formulation of the worm sex. the fir pheromone (E / Z - 11 -tetradecenal 95/5). The deposit of the formulation was ascertained, in part, by deploying water-sensitive deposit cards throughout the site and collecting the foliage samples following the aerial spraying. The samples were taken at the levels of the lower, middle and upper cups of the fir trees of 10 meters. Foliage sampling was continued, along with air sampling, during the duration of the experiment as follows.

Field Evaluation Air Determinations Air sampling was started within 24 hours, following the application of the formulation and repeated every four or five days through the duration of the estimated adult flight period. The two sampling locations were designated near the center of the test lot of approximately 5 ha and separated by approximately 20 feet. Two cubic meters of air were extracted by means of 25 g of absorbent (in a 3 x 20 cm glass column) for a period of two hours. The absorber was stored at -10 ° C until the extraction, concentration and quantification of the solvent by gas electrophoretic chromatography (GC-EAD) detection.

Foliage Determinations Samples were collected from intersection branches of two, six points within 24 hours of the application of the formulation and approximately every four or five days thereafter, until the end of the adult flight. The foliage samples were stored at -10 ° C until extraction and quantification of the solvent by GC-FID and / or GC / EAD.

Laboratory Evaluation The laboratory / field evaluation protocols were also placed in the appropriate place. The pheromone formulation is applied to the foliage surface in known quantities and the foliage is exposed to a variety of environmental conditions for several weeks (control for wind, rain and the impact of the sun on the adhesion of the formulation). and the release speed). The foliage samples are taken periodically and the liberated pheromone is quantified as well as the residual pheromone that remains in the foliage during the time.

Formulation Evaluation (a) Air samples were analyzed for pheromone levels using the GC-EAD technique. These samples contained pheromone levels (c 1 mg / m3) at the beginning of the experiment and very low levels (1-10 pg / m3) three to four weeks later. (b) foliage samples were collected for analysis. (c) The laboratory evaluation of the known quantities of release characteristics of the pheromone formulation was placed on small spruce trees and these trees were kept at different environmental conditions. In all the tests, the amount of the formulation that contains the pheromone that remained in the foliage was carried out, even after four weeks on the trees exposed to all the elements (wind, rain and sun); was approximately 5-10% of that applied at the beginning of the experiment. The effects of sun and rain on the longevity of the formulation were apparent. The samples of the branches taken during the test period for pheromone release were examined. The pheromone was still released from the formulation in the branches during the total trial period of four weeks.

Z-10-Nonadecenal Methods for the Z-10-nonadecenal The formulation of the pheromone, was applied aerially by helicopter at a rate of -100 g of the active ingredient / ha to a test site and, to a control site It contains black firs. Three fir trees were also sprayed (portable atomizer) with the additional formulation for the purpose of evaluation of the formulation. The deposit of the formulation was verified in part with the water sensitive drip cards placed in the batch before spraying.

Field Evaluation Air Determinations As described above for the E / Z-ll-tetradecenal.

Foliage determinations As described above for the E / Z-ll-tetradecenal.

Results The studies of the evaluation of the laboratory formulation that were carried out during the spring and the summer, show that a prolonged release of four weeks of the pheromone of the sawfly (Zl 0 -nonadecenal) of the formulation was obtained MEC applied to small spruce trees. Approximately 5% of the applied formulation remained on the trees exposed to the elements for a period of four weeks. Still, low levels of the pheromone released from the foliage samples were detected after approximately five weeks. The results of the laboratory evaluation indicate that the formulation has a lifespan of at least four weeks with prolonged release.

It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention.

Claims (17)

CLAIMS Having described the invention as above, the content of the following claims is claimed as property.

1. A process for encapsulating an organic material partially miscible with water within the polyurea or polyurethane layer, characterized in that it comprises: (a) providing an aqueous phase containing a surfactant; (b) dispersing in the aqueous phase a water-immiscible organic solvent in which the partially miscible material in water to be encapsulated and a polyisocyanate, are dissolved or dispersed, to form a dispersion of droplets of the organic solvent in the continuous aqueous phase; (c) adding a tertiary amine soluble in water to the dispersion; (d) subsequently adding to the dispersion a polyfunctional compound containing the functional groups selected from the group consisting of primary amine, secondary amine and hydroxy groups, whereby discrete capsules composed of the encapsulated material are formed in a layer of polyurea or polyurethane.

2. A process according to claim 1, characterized in that the tertiary amine is added to the aqueous dispersion in at least about two minutes before the addition of the polyfunctional compound to the aqueous dispersion.

3. A process according to claim 2, characterized in that the tertiary amine is triethylamine.

4. A process according to claim 1, characterized in that the encapsulated material is an alcohol, aldehyde, ketone, acid, ether or mercaptan.

5. A process according to claim 1, characterized in that the encapsulated material is an organic compound having a molecular weight in the range from about 100 to about 400 and has one, two or three oxygen atoms.

6. A process according to claim 1, characterized in that a pheromone partially miscible with water is encapsulated and the surfactant is a polyvinylpyrrolidone (PVP).

7. A process according to claim 1, characterized in that a partially water-immiscible pheromone is encapsulated and the surfactant is a poly (ethyleneoxy) nonylphenol.

8. A process according to claim 1, characterized in that the polyisocyanate is a polymethylene polyphenylisocyanate. A process according to claim 1, characterized in that the polyisocyanate is selected from the group consisting of 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, isophorone diisocyanate, naphthalene diisocyanate and 2,4,6-toluene triisocyanate 10. A process according to claim 8, characterized in that the polymethylene polyphenylisocyanate is of the formula: wherein n is from 2 to 4. 11. A process according to claim 1, characterized in that the polyfunctional compound is an amine containing at least 4 nitrogen atoms. 12. A process according to claim 11, characterized in that the polyfunctional compound is tetraethylene pentamine. 13. A process according to claim 1, characterized in that the diameter of the polyurea layer is from about 10 micrometers to about 60 micrometers. 14. Microcapsules composed of a material that is partially miscible in water, encapsulated within a polyurea / polyurethane layer, characterized in that the amount of the encapsulated material is at least 5%. The microcapsules according to claim 13, characterized in that the encapsulated material is a pheromone partially miscible in water and the encapsulated amount is at least 9%. 16. The microcapsules according to claim 14, characterized in that they have a specific density of less than 1. 17. A method for combating an organism of pests in agriculture, horticulture or forestry, characterized in that the method comprises applying to the organism of pests. or to the habitat thereof, or to a crop to be protected, microcapsules composed of a material partially miscible with water that interferes with a life process essential for the survival of the white pests, the material is encapsulated in a layer of polyurea or polyurethane which also contains a tertiary amine soluble in water.