CN1805784A - Encapsulated essential oils - Google Patents

Abstract

The present invention provides a process for the preparation of essential oil microcapsules, which comprises dissolving a di-or polyisocyanate in an essential oil, emulsifying the resulting mixture in an aqueous solution containing a di-or polyamine and/or a di-or polyhydroxy compound, thereby effecting encapsulation of the essential oil by interfacial polymerization to form a polyurea and/or polyurethane film around the essential oil droplets, which film enhances the stability of the essential oil, reduces its evaporation rate and controls its release rate on application to a substrate.

Description

Encapsulated Essential Oils

The present application relates to microcapsules of essential oils, their preparation and their use: as a green sanitizing product for the consumer market such as hard surface cleaners, laundry detergents and softeners; Use of insecticides such as larvicides; use such as repellants against eg mosquitos, ants and other insects and use as antiviral and antifungal agents. The present invention also provides a disinfectant or pesticide or insect repellent and larvicide composition comprising essential oils encapsulated in microcapsules having a capsule wall mainly composed of diisocyanate or polyisocyanate and polyfunctional Amines are optionally formed as reaction products in the presence of difunctional or polyfunctional alcohols. The present invention also provides a method for encapsulating essential oils in microcapsule formulations comprising an aqueous phase containing an emulsifier and a suspending agent: an organic phase is provided, which is an essential oil containing diisocyanate or polyisocyanate, and the aqueous phase and the organic phase are The phases are combined to form an oil-in-water emulsion to which an aqueous solution of a difunctional or polyfunctional amine and a difunctional or polyfunctional alcohol is added with stirring, thereby reacting the amine and alcohol with the isocyanate to form Microencapsulated coating around essential oils.

More specifically, according to the present invention, there is now provided a method for preparing essential oil microcapsules, comprising dissolving diisocyanate or polyisocyanate in essential oil, in an aqueous solution containing diamine or polyamine and/or dihydroxy compound or polyhydroxy compound The resulting mixture is emulsified in the medium, and the encapsulation of the essential oil is carried out by interfacial polymerization to form a polyurea and/or polyurethane film around the essential oil droplets, which film is able to increase the stability of the essential oil, reduce its evaporation rate and control Its rate of release when applied to a substrate.

In a preferred embodiment of the present invention, the polymerization reaction is carried out at a temperature of 0°C to 30°C.

Preferably the mixture also comprises a catalyst.

In a preferred embodiment, the aqueous solution further comprises a diol or polyol and optionally further comprises a diamine or polyamine.

Preferably, the aqueous solution also comprises at least one emulsifier.

Also preferred is a method wherein the essential oil is encapsulated together with other ingredients selected from adjuvants and agents capable of enhancing the properties of the essential oil, preferably sesame oil.

In a preferred embodiment of the invention, said encapsulation is carried out by dissolving the polyisocyanate in said essential oil under ambient conditions in an aqueous solution containing polyamines and/or diols or polyols. The resulting mixture is emulsified in solution where a preliminary reaction takes place which forms a film and consumes all of the polyamine present, then the slower reacting polyol reacts and forms an outer cross-linked coating which is further consumed with water any residual isocyanate to form an amine that reacts with any residual isocyanate.

Alternatively, the method can also be carried out in the absence of diamines or polyamines in the aqueous solution.

In the method of the present invention, preferably the diisocyanate or polyisocyanate is selected from the group consisting of dicyclohexylmethane 4,4'-diisocyanate; hexamethylene 1,6-diisocyanate; isophorone diisocyanate; trimethyl Hexamethylene diisocyanate; trimer of hexamethylene 1,6-diisocyanate; trimer of isophorone diisocyanate; 1,4-cyclohexane diisocyanate; 1,4-(dimethyl (isocyanato) cyclohexane; biuret of hexamethylene diisocyanate; urea of hexamethylene diisocyanate; trimethylene diisocyanate; propylene-1,2-diisocyanate and butylene-1, 2-Diisocyanates; mixtures of aliphatic diisocyanates and aliphatic triisocyanates, tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate and 4-(isocyanatomethyl)-1,8 - Octyl diisocyanate, aromatic polyisocyanates including 2,4-toluene diisocyanate and 2,6-toluene diisocyanate, naphthalene diisocyanate, diphenylmethane diisocyanate and triphenylmethane -p,p',p" - Trityl triisocyanate. Suitable aromatic isocyanates are toluene diisocyanate, polymethylene polyphenylisocyanate, 2,4,4'-diphenylether triisocyanate, 3,3'-dimethyl- 4,4′-diphenyl diisocyanate, 3,3′-dimethoxy-4,4′-diphenyl diisocyanate, 1,5-naphthalene diisocyanate and 4,4′,4″-triphenyl Methyl methane triisocyanate and isophorone diisocyanate.

Preferably, the diamine or polyamine is selected from ethylenediamine, diethylenetriamine, propylenediamine, tetraethylenepentamine, pentamethylenehexamine, α, ω-diamine, propylene- 1,3-diamine, tetramethylenediamine, pentamethylenediamine and 1,6-hexamethylenediamine, polyethyleneamine, diethylenetriamine, triethylenetriamine, pentaethylene Hexamethylene, 1,3-phenylenediamine, 2,4-toluenediamine, 4,4'-diaminodiphenylmethane, 1,5-diaminonaphthalene, 1,3,5-triaminobenzene, 2,4,6-triaminotoluene, 1,3,6-triaminonaphthalene, 2,4,4'-triaminodiphenyl ether, 3,4,5-triamino-1,2,4-tri oxazole, bis(hexamethylenetriamine) and 1,4,5,8-tetraaminoanthraquinone.

Preferably, the dihydric alcohol or polyhydric alcohol is selected from such as ethylene glycol, diethylene glycol, propylene glycol, 1,4-butanediol, 1,4-hexanediol, dipropylene glycol, cyclohexyl-1,4 -Dimethanol, 1,8-octanediol and other polyols, and polyols with an average molecular weight of 200 to 2000 such as polyethylene glycol, polypropylene glycol, polytetramethylene glycol, trimethylolpropane, glycerin, Hexatriol and pentaerythritol, 1,3-dihydroxybenzene, 2,4-dihydroxytoluene, 4,4'-dihydroxydiphenylmethane, 1,5-dihydroxynaphthalene, 1,3,5-trihydroxybenzene , 2,4,6-trihydroxytoluene, 1,3,6-trihydroxynaphthalene, 2,4,4'-trihydroxydiphenyl ether and hydrolyzed polyvinyl alcohol.

Preferably, the catalyst is selected from such as N,N-dimethylaminoethanol, N,N-dimethylcyclohexylamine, bis(2-dimethylaminoethyl)ether, N,N-dimethyl Amino compounds or organometallic compounds such as hexadecylamine, diaminobicyclooctane, stannous octoate and dibutyltin dilaurate, the concentration of which is 0.1% to 0.3% by weight based on the glycol, and such as triethylamine or Tertiary amines such as diethylmethylamine and metal salts of Cu, Pb, Zn, Co, Ni, and Mn.

In a particularly preferred embodiment of the invention, emulsifiers, dispersants and sterically hindering polymers which prevent aggregation of the microcapsules are used by adding these substances to the aqueous solution used for the preparation of the microcapsules. These emulsifiers, steric hindrance agents can be selected from sodium lignosulfonate, potassium lignosulfonate, magnesium lignosulfonate, calcium lignosulfonate or ammonium lignosulfonate; low density and high density polyvinyl alcohol, Or Tween 20, 40 or 80, and use selected from carboxymethylcellulose, sodium salt, xanthan gum (Xantangum), pecan (Karya) gum and locust bean gum, polyvinylpyrrolidone (PVP), with Water-soluble polyvinyl alcohol (PVA) with different acetate hydrolysis degrees (as one of the most preferred ranges, the degree of hydrolysis is 80% to 90%, and the other range is a degree of hydrolysis above 95%) and poly(ethoxy)nonyl A suspending agent such as phenol is used to form a dispersion. PVP is available in various molecular weights ranging from about 20,000 to about 90,000; poly(ethoxy)nonylphenols have various molecular weights depending on the length of the ethoxy chain. Poly(ethoxy)nonylphenol, polyether block copolymers, polyethylene oxide adducts of fatty alcohols, surfactants and esters of fatty acids such as stearate, oleate, sorbitan-hard Fatty acid ester, sorbitan monooleate, sorbitan sesquioleate. Each of the emulsifiers, dispersants and steric hindrance polymers mentioned above may be used alone or in combination. Typically they are added to the aqueous solution prior to dispersing the non-aqueous essential oil/isocyanate, or in some cases during or after interfacial polymerization.

In a particularly preferred embodiment of the invention, the resulting microcapsules comprise 60% to 95% essential oils, the remainder of said microcapsules comprising capsule walls and additives.

Preferably, the average size of the obtained microcapsules is 10 μm to 100 μm.

In a particularly preferred embodiment of the invention, the resulting microcapsules contain essential oils as larvicide, the microcapsules have a size of 0.5 μm to 100 μm and are optionally adapted to float on water, the microcapsules will not Degraded by ultraviolet (UV) radiation and capable of slowly releasing effective doses of essential oil pesticides encapsulated therein.

In other preferred embodiments of the present invention, the resulting microcapsules contain essential oils as larvicide, the microcapsules have a size of 0.5 μm to 100 μm, and optionally, the microcapsules are adapted to float on water, and Optionally, the microcapsules are not degraded by ultraviolet radiation and are capable of slowly releasing an effective dose of the essential oil pesticide encapsulated therein.

In a further preferred embodiment of the present invention, the obtained microcapsules contain essential oil as a larvicide, the microcapsules have a size of 0.5 μm to 100 μm, and can slowly release an effective dose of the essential oil insect repellant encapsulated therein .

According to the present invention it is also possible to provide a method wherein the obtained microcapsules contain essential oils as larvicide, the microcapsules have a size of 0.5 μm to 100 μm, the microcapsules are optionally not degraded by ultraviolet radiation, and can Slow release of an effective dose of essential oil repellent encapsulated within.

In another aspect of the invention, the resulting microcapsules contain essential oils that are used in consumer products as a substitute for chlorine-containing disinfectants and possess sustained antibacterial activity.

In yet another aspect of the present invention, the microcapsules are reacted with active amines or hydroxyl-containing reagents after formation, and the active amines or hydroxyl-containing reagents also contain anionic groups or cationic groups or amphoteric groups or hydrophilic groups. Water groups which render the surface of the microcapsules of encapsulated essential oil anionic or cationic or amphoteric, or hydrophilic but uncharged.

In another aspect of the invention, the microcapsules are post-modified after formation by absorbing monomers or polymers on their surfaces, which can increase their hydrophilicity or hydrophobicity, or make their surfaces Anionic or cationic or amphoteric, or hydrophilic but uncharged.

The present invention also provides essential oil microcapsules prepared by any of the above methods.

In one embodiment of the present invention, microcapsules are formed by encapsulating essential oils in polyurea or polyurethane microcapsules by interfacial polymerization at room temperature. The properties of these capsules are that they prevent the evaporation or oxidation of the encapsulated essential oils and allow them to be absorbed and retained on the surface to which they are applied, as well as their slow release properties. Encapsulation methods and capsule membrane materials provide essential oil formulations with low or no toxicity and are ecologically safe [termed "green"] that overcome the toxicity and inefficiencies of existing materials and technologies aspect limitations.

In another embodiment of the present invention, slow-release essential oil microencapsulated formulations for mosquito control are said to be competitive "green" alternatives to currently used synthetic chemicals. The formulations of the present invention will also improve their performance at a lower cost than other natural larvicides. Microencapsulation by interfacial polymerization to form polyurea and polyurethane films at the interface reduces the effective concentration required for each application and increases the duration of activity. For purported larvicide use, essential oil microcapsules are micron-sized encapsulated particles of essential oils that float on water, are not degraded by UV radiation, and are capable of slow release of an effective dose.

In another embodiment, the essential oil microcapsules of the present invention will be used to replace chlorine-containing disinfectants in consumer products, which have good sustained antimicrobial activity, where the essential oil microcapsules of the present invention are often required, such as in hard surface cleaners and detergents. capsule.

In another preferred embodiment of the invention, encapsulation is carried out by dissolving bisphenol A-based polyisocyanates in essential oils in the presence of polyamines and diols or polyols (e.g. polyethylene glycol [ PEG]) in water to emulsify the mixture. A preliminary reaction occurs which forms the membrane and consumes all of the polyamine. The slower reacting polyol then reacts and forms an outer cross-linked coating. Any residual isocyanate is further consumed with water to form an amine which reacts with the residual isocyanate. The final product contains only microcapsules dispersed in water without residual toxic chemicals. The solution was not further purified and other substances were added to form the final formulation.

In another preferred embodiment of the invention, encapsulation is carried out by dissolving bisphenol A-based polyisocyanates in essential oils in the presence of diols or polyols (e.g. polyethylene glycol [PEG]) emulsify the mixture in water. A preliminary reaction occurs which forms the film and primarily results in a polyurethane encapsulating coating with a minimum of urea groups formed by hydrolyzing the isocyanate with water and reacting the resulting amine with the remaining isocyanate groups. The final product contains only microcapsules dispersed in water without residual toxic chemicals. The solution does not require further purification and other substances are added to form the final formulation.

In other preferred embodiments of the present invention, the microcapsules are formed and reacted with reagents containing active amines or hydroxyl groups, which also contain anionic or cationic or amphoteric or hydrophilic groups, which makes the encapsulated essential oil The surface of the microcapsules is anionic or cationic or amphoteric, or hydrophilic but uncharged.

In a further preferred embodiment of the present invention, the microcapsules are post-modified after formation by absorbing monomers or polymers onto their surface which are capable of increasing their hydrophilicity or Hydrophobic, or make its surface anionic or cationic or amphoteric, or hydrophilic but uncharged.

In another embodiment, an essential oil is encapsulated with an adjuvant or agent that enhances the properties of the essential oil, such as sesame oil that contains ingredients that enhance the properties of other essential oils as larvicides or antibacterials.

In a particularly preferred embodiment of the invention, the method is characterized in that the essential oil is encapsulated at room temperature in firm polyurea or polyurethane microcapsules formed by interfacial polymerization. By controlling factors such as: the nature and concentration of the reactants and the conditions under which the reaction takes place, such as pH, ionic strength, temperature, presence of emulsifying agents, suspending agents, solvents, it is possible to achieve a more efficient encapsulation of the above-mentioned essential oils than other methods hitherto used to encapsulate the above-mentioned essential oils. Effectively control the size of microcapsules and the permeability of the encapsulation barrier to essential oils. By this method, essential oils can serve as effective green alternatives to toxic chemicals currently used, and such essential oils have significantly improved efficacy compared to non-encapsulated essential oils and essential oils encapsulated using other methods. Encapsulation is required since non-encapsulated products based on essential oils are extremely sensitive to oxidation and volatilization, properties that compromise their efficacy, and the capsule needs to be protected from oxidation and volatilization. The encapsulated essential oils listed in the prior art do not have adsorption and retention capacity with respect to the surface to which they are applied and/or do not have the desired sustained release properties, which are required for a product with low cost. The release profile of prior art microencapsulated essential oils is either too fast or too slow and/or not released at a constant rate. The capsules of our invention have the necessary properties to enable them to be adsorbed and retained on the surface to which they are applied, with the desired sustained release properties. The method of encapsulation and the material used for the capsule film provide an ideal essential oil formulation as a sustained release product, which overcomes the limitations of existing materials and technologies, which can enhance the stability and duration of the activity of the active material, and The quantity required is reduced, thereby reducing production costs. Since this unique microcapsule of essential oil is new and has the desired adsorption and sustained release properties, it has been extensively explored, but has not yet been obtained at a low cost compared to synthetic chemicals" Green" material.

Background technique

Before the emergence of modern chemical and pharmaceutical industries, essential oils were used as antiseptic and antiseptic materials for pharmaceutical and cosmetic purposes in many areas of daily life, such as antibacterial (antiviral, bactericidal and antifungal) Larvicide. Essential oil-based formulations with broad-spectrum antimicrobial activity have been found to be relatively nontoxic to mammals, especially for essential oil-based surface cleaning compositions, which are particularly effective disinfectants and antiseptics, but they have been Substitution of more effective synthetic chemicals and antimicrobials as they are cheaper, more effective and can be used at lower concentrations. However, the toxicity and environmental impact of synthetic chemicals has gradually become apparent over time, so efforts are now being made to replace synthetic chemicals with the above-mentioned essential oil agents that were once discarded.

In the field of disinfectants for consumer products, there is a need for safe alternatives to synthetic chemicals and antibiotics used as disinfectants and antiseptics for currently used chemicals showing toxicity to humans and the environment. Some disinfectants have been reported to be chronically toxic especially to small children. There is thus a need to replace chemicals containing active chlorine and other synthetic chemicals with non-toxic, natural "green" materials. Aromatic natural essential oils with little or no toxicity have shown good antimicrobial properties and are therefore strong candidates for use in replacing chlorine-based disinfectants. We have demonstrated good antimicrobial activity of eucalyptus oil in fabric softening applications. However, the lack of access to the consumer market for essential oil products, including current encapsulated formulations, is due to the price of raw materials, lack of sustained activity, and the need for repeated applications.

In the field of pesticides, the present microcapsules can be used in applications such as larvicides, insect repellents and insecticides. For larvicide applications, essential oil microencapsulations for mosquito control can be combined with existing process larvicides [organophosphates, organochlorides, carbamates, petroleum oils, insect growth regulators (IGR) ( For example, Mengwuyiwu or Bailipfen)] compete.

Two important reasons for controlling mosquitoes are to avoid annoying bites and to prevent the spread of mosquito-borne diseases such as malaria, encephalitis, dengue and yellow fever, and West Nile virus. The World Health Organization estimates that more than 500 million clinical cases are attributed to pathogens carried and transmitted by mosquitoes each year. The recent dramatic increase in mosquito-borne diseases in the United States has significantly increased the commercial value of larvicides. Currently, chemical insecticides are used as larvicides or adulticides to control mosquitoes even though the insecticides may harm human health and are known to have harmful effects on the environment and wildlife. Biolarvicides are primarily microorganism-based products that are registered as pesticides for outdoor control of mosquito larvae. In addition to being expensive, biological products are difficult to apply effectively because the duration of effectiveness depends largely on the product formulation, environmental conditions, water quality and mosquito species. Spray with kly 2% of mineral oil.

The purposes of microcapsule of the present invention:

Non-toxic larvicide, cleaner for hard surfaces, laundry detergent, diapers, feminine tampons, fabric softener. Insect repellent especially against mosquitoes and ants.

The essential oil microcapsules of the present invention have the following uses. In a given application, the use of the microcapsules of the present invention increases the potency of essential oils by reducing the amount needed to prolong the activity, thereby reducing the cost of use and making essential oils competitive with current synthetic chemicals .

1) Disinfectants and cleaning compositions for hard surfaces such as counter tops, tiles, porcelain products (sinks and toilets), floors, windows, tableware, glassware, dishes, and dental and surgical appliances;

2) Spices and lotions applied to textile structures to improve the physiological condition of the skin;

3) Highly effective antibacterial wipes for rapid bacterial reduction described in the following U.S. patents described in the "Comparison with the Prior Art" section on essential oils;

4) Long-acting antimicrobial composition with high residual effect against Gram-positive bacteria described in the following US patents described in the "Comparison with prior art" section on essential oils;

5) Antimicrobial compositions formulated with essential oils described in the following U.S. patents described in the "Comparison with the Prior Art" section on essential oils;

6) Essential oil-based disinfectant and cleaning compositions described in the following U.S. patents described in the "Comparison with the Prior Art" section on essential oils;

7) Blooming agents in germicidal hard surface cleaning compositions;

8) Liquid detergent compositions;

9) Antibacterial compositions having antiseptic, antiviral and larvicidal activity, for example for the treatment of cold sores, head lice, vaginitis, warts, warts and athlete's foot, and as antiseptic mouthwashes and surface cleaners;

10) pediculicide;

11) Natural pesticides;

12) Flavoring agent;

13) Fragrances;

14) Therapeutic agents for human and animal infectious diseases;

15) lice repellent composition;

16) Analgesic and anti-inflammatory compositions;

17) Fragrance or insect repellant;

18) Active agents in pharmaceuticals and cosmetics;

19) Benefit agents in extruded soap and/or cleanser bars;

20) Food or tobacco additives;

21) Active agents in pharmaceuticals and cosmetics;

22) hair care products; and

23) Toothpaste containing encapsulated flavor.

24) Repellants for mosquitoes, ants and insects

25) Larvicide

26) Antiviral agent

27) Antifungal agents

28) Gel for gum diseases

29) Feminine tampons that don't cause toxic syndrome

30) Diapers

Comparison with Existing Technology

A review of the prior art shows that essential oils have been used in many different compositions for the various purposes mentioned above. Although encapsulation of this oil has been used to improve stability, facilitate sustained release, and reduce application cost (for the same uses that we propose to develop), to our knowledge, these efforts have not yet produced a Currently available synthetic chemicals compete with commercial products. The reason for this is that currently used essential oils, including those that have been encapsulated, do not meet one or more of the above-mentioned requirements for the manufacture of microencapsulated products with low cost. Disadvantages of currently available products include:

1) they do not have a sufficiently long shelf-life on the surface to which they are applied due to an unsuitable encapsulation barrier, and/or do not sustain effective dose release on these matrices;

2) They are manufactured by processes that destroy or alter many of the properties of oils; and

3) In many cases, they must be used in higher than low cost dosages to be effective, thus costing significantly more than currently available synthetic chemicals.

Patent literature related to encapsulated essential oils can be divided into the following categories:

1) A category of patents that describe all methods of encapsulation and a wide range of polymeric sealants, but only give limited examples and claims;

2) a class of patents based on a solid core containing essential oils absorbed inside, with and without an accompanying coating;

3) Encapsulation of essential oil droplets or emulsions within the polymer shell by coagulation or adsorption of prefabricated polymers;

4) Encapsulation of essential oil droplets or emulsions within polymer shells by coagulation or adsorption of preformed polymers; and

5) Encapsulation within the microorganism. The prior art closer to this patent is the encapsulation of essential oil as liquid core. All encapsulation methods and a wide range of polymeric sealants are described in patents US 3,957,964, US 5,411,992, US 6,414,036, but only limited examples are given and claimed. None of the examples or claims specifically refer to interfacial polymerization to form polyurethane or polyurea encapsulated essential oils.

In patents US 6,238,677, US 5,753,264, US 6,200,572, PCT/PUBLICATION-1997-07-09A1, it involves the encapsulation of essential oil droplets or emulsions in polymer shells by coagulation or adsorption of prefabricated polymers. These patents are not related to our proposed patents and, due to the nature of their microcapsule walls, do not actually have the necessary sustained release or required stability in our application.

In patent US 5,232,769, the encapsulation of essential oil droplets or emulsions within a polymer shell is carried out by interfacial polymerization of monomers such as melamine or urea dissolved in essential oil droplets, and by interfacial crosslinking of formaldehyde. In this case there is no sustained release, and the microcapsules, in the case of formaldehyde, melamine or urea, are hard and give a bad feel to the surface to which they are applied.

The method of forming polyurea and polyurethane microcapsules by interfacial polymerization has been widely used in the encapsulation of pesticides and herbicides [see A. Markus, Advances in the technology of controlled release pesticide formulations” in Micro-encapsulation: Methods and Industrial Applications, S. Benita (Ed), 1996, pp. 73-91, and U.S. Patent US 4,851,227, Jul. 25, 1989]. These methods and materials have not yet been used in the encapsulation of essential oils, but it is indeed surprising that they Works well with non-toxic essential oils. The use of interfacial condensation to encapsulate substances such as drugs, pesticides and herbicides is discussed in US3,577,515, issued May 4, 1971. The encapsulation method involves two mutually immiscible The liquid phase, where one phase is dispersed in the other by agitation, followed by polymerization of the monomers from each phase at the interface between the bulk (continuous) phase and the dispersed droplets. The immiscible liquids are usually water and Organic solvents. Polyurethanes and polyureas are among the types of materials suitable for making microcapsules. The use of emulsifying agents (also known as suspending or dispersing agents) is also discussed. U.S. patents disclose Capsules are formed with diameters ranging from 30 μm to 2 mm, depending on the monomers and solvents used.

The use of interfacial condensation to encapsulate substances such as drugs, pesticides and herbicides is discussed in US 3,577,515, issued May 4,1971. The encapsulation process involves two immiscible liquid phases, one phase is dispersed in the other by agitation, followed by the separation of monomers from each phase at the interface between the bulk (continuous) phase and the dispersed droplets. polymerization. The immiscible liquids are usually water and organic solvents. Among the types of materials suitable for making microcapsules are polyurethanes and polyureas. The use of emulsifying agents (also known as suspending or dispersing agents) is also discussed. US patents disclose the formation of microcapsules comprising polymer spheres and liquid cores, with diameters ranging from 30 μm to 2 mm, depending on the monomers and solvents used.

British Patent 1,371,179 discloses the preparation of polyurea capsules containing dyes, inks, chemical agents, drugs, flavoring materials, fungicides, bactericides and pesticides such as herbicides and insecticides. These capsules are prepared from various diisocyanates and polyisocyanates in a dispersed organic phase. Some of the isocyanate present reacts with water to form amines which can further react at the interface with the remaining isocyanate, which is then polymerized to form the polyurea shell. The aqueous phase also contains surfactants such as ethoxylated nonylphenols or polyethylene glycol ethers of linear alcohols. Additionally, the aqueous phase contains protective colloids, typically polyacrylates, methylcellulose, and polyvinyl alcohol (PVA). For example the particle size may be as small as 1 μm. Encapsulation of insect hormones and mimetics is also included in the mentioned systems.

US Patent 4,046,741 and US Patent 4,140,516 appear to relate to the development of the method disclosed in UK Patent 1,371,179. According to US Patent US 4,046,741, the problem associated with microcapsules is the instability caused by the evolution of carbon dioxide from the residual isocyanate encapsulated in the microcapsules. US Patent No. 4,046,741 discloses post-treatment of polyurea microcapsules with ammonia or amines such as diethylamine. This removes residual isocyanate, allowing subsequent storage of the microcapsules at lower pH without carbon dioxide generation. US Patent No. 4,140,516 discloses the use of quaternary salts as phase transfer catalysts to accelerate the formation of polyurea microcapsules.

Canadian Patent 1,044,134 relates to microencapsulation of insecticides, particularly pyrethroids. The insecticide is dissolved together with the polyisocyanate in a water-immiscible organic solvent. The solution in the organic solvent is then dispersed in water by stirring, and the polyfunctional amine is added while stirring continuously. The polyisocyanate and polyfunctional amine react to form a polyurea shell wall around the dispersed insecticide-containing droplets.

Microencapsulation (or encapsulation) of active agents is a known method to control their release and improve shelf life and duration of activity. Encapsulated sustained release formulations based on active agents enable the manufacture of lower cost products than non-encapsulated products. Many other hydrophobic or water-insoluble agents such as pesticides have been successfully encapsulated by various methods. Microcapsules are flowable powders or powders with a particle size of about 0.1 μm to 1000 μm. They can be produced using various coating methods in which finely divided solid, liquid or even gaseous substances can be used. Polymers are often used as coating materials or wall materials. Basically, microcapsules consist of two completely different regions, the core region and the coating region. The methods suitable for preparing microcapsules include: phase separation method (simple coacervation and complex coacervation), interfacial polymerization method (polycondensation or polyaddition of dispersion liquid) and physical mechanical method (fluidized bed method, spray drying). The main disadvantage of traditional microcapsules is the relative complexity of preparation.

Encapsulation of substances such as pharmaceuticals, pesticides (including insecticides, nematicides, herbicides, fungicides and microbicides), preservatives, vitamins and flavoring agents is desirable for many reasons. In the case of pharmaceuticals and pesticides, encapsulation can provide controlled release of the active substance. In the case of vitamins, encapsulation can be performed to protect the vitamin from oxidation, thus extending its shelf life. In the case of flavors, encapsulation may be performed to place the flavor in a readily metered form which releases the flavor upon a controllable trigger, such as the addition of water. Those of ordinary skill in the art of flavor encapsulation are generally aware that current practical commercial methods for producing stable, dry flavors are generally limited to spray drying and extrusion coagulation. The former method requires emulsification or dissolution of the fragrance in a liquid carrier containing an encapsulated solid, followed by drying in high temperature, high velocity gas and collection as a low bulk density solid.

Although most commercial encapsulation materials are processed by spray drying, some limitations of this method are evident. Low molecular weight components of complexes or natural flavor blends may be lost or disproportioned in this process. The resulting perfume carrier is porous and difficult to handle. In addition, harmful chemical reactions such as oxidation can occur on the exposed surfaces during and after the drying process. The final product, a dry free-flowing powder, will rapidly release the encapsulant due to rehydration, whether rapid release is desired or not.

There are also encapsulated forms of larvicides based on materials other than essential oils. For example, ALTOSID ^(R) produced by Wellmark International is a microencapsulated larvicide that has been used in the United States to reduce mosquito infestation by preventing immature mosquito larvae from becoming disease-transmitting adults. The active ingredient, Mengwuyiwu, is an insect growth regulator that interferes with the normal development of mosquitoes.

Microcapsule properties of the present invention

Encapsulation is required for slow release and improved stability of essential oils, both properties are desirable for manufacturing products at low cost. Essential oil-based products are extremely sensitive to oxidation and evaporation, properties that compromise their efficacy and require encapsulation to prevent oxidation and evaporation. Many "green" materials, including essential oils, are less efficient and more expensive than the synthetic chemicals they seek to replace. There is thus a need to manufacture these "green" materials with smaller effective doses and to increase efficacy by increasing the duration of activity per unit dose. Our proposed product is a sustained release formulation that will meet the above needs in the form of encapsulated essential oils. When applied to a given substrate, the oil will be released at a constant rate for an extended period of time, thereby increasing the duration of activity per dose and reducing the amount required, thereby reducing the cost of the product. Encapsulation also stabilizes the essential oil from oxidation and volatilization, a required step for product formulation, shelf life, usage and duration of activity upon application.

The microcapsules of the present invention are micron-sized microcapsules containing essential oil liquid cores obtained through a low-cost method with high encapsulation efficiency and low oil loss. The resulting microcapsules release the effective dose at a constant rate (known in terminology as zero-order release), providing a longer duration of activity than the same amount of non-encapsulated essential oil. The above requirements can be met by our room-temperature interfacially formed microcapsules formed from agents that can form polyurea or polyurethane films around dispersed oil droplets. The permeability of strong polyurea or polyurethane films is readily controlled by polymerization conditions, composition of reactants, and catalyst. The resulting material is non-toxic and ultimately biodegradable.

There are many requirements for competing microencapsulated essential oil formulations which can be met by the room temperature interfacially formed microcapsules of the present invention made of agents that can form polyurea or polyurethane films around dispersed oil droplets form. The following requirements must be met:

1) Microcapsules must be spherical, which ensures the smallest surface area per unit volume, thus providing effective controlled release and maximum flow characteristics at the same time;

2) In order to produce an aesthetically pleasing, uniform and easy-to-use formulation that does not have an unsightly rough appearance or unpleasant tactile feel when applied to a given surface, the capsules need to be nanometer to micrometer sized;

3) The microcapsules should consist of a thin outer polymer film encapsulating an essential oil liquid core. The polymer film controls the release of oil and prevents it from oxidation or evaporation. The configuration with a liquid core encapsulated within a spherical membrane ensures an ideal constant and sustained release pattern (termed zero-order release);

4) The cross-link density and hydrophobic/hydrophilic balance of the encapsulating film should be adjusted to provide the desired duration of controlled release;

5) The encapsulating film should be strong and not brittle to facilitate machining and provide a smooth feel to the surface, as is required in some applications for hard surfaces and textiles;

6) Microcapsules need to be formed in aqueous solution at low temperature or room temperature to prevent oil properties from changing at high temperature and minimize product cost;

7) Microcapsules provide surface properties such as charge required for adsorption; and

8) In order to facilitate imparting the regulatory function, the encapsulating film and reagents used in the product should be cheap, thereby providing an economical product (non-carcinogenic, non-deformation-inducing, and free of heavy metals).

These above requirements can be met by our method of interfacially forming microcapsules with reagents that form polyurea or polyurethane films around dispersed oil droplets or emulsions at room temperature. However, the same requirements cannot yet be met by currently available technologies.

Contents of the invention

Essential oils include, but are not limited to, the following oils: cottonseed oil, soybean oil, cinnamon oil, corn oil, cedar oil, castor oil, clove oil, geranium oil, lemongrass oil, linseed oil, peppermint oil, sesame oil, thyme oil , rosemary oil, anise oil, basil oil, camphor oil, citronella oil, eucalyptus oil, fennel oil, grapefruit oil, lemon oil, orange oil, orange oil, pine needle oil, pepper oil, rose oil, tangerine oil, tea tree oil, camellia oil, amaranth oil, garlic oil, sesame oil, onion oil, rosemary oil, citronella oil, lavender oil, geranium oil, almond oil, spearmint oil. These oils can be packaged individually or in any combination. For example, sesame oil can be used in larvicides to enhance the efficacy of pine oil, or in the case of mosquito repellents, active ingredients such as citronella oil, lavender oil, geranium oil etc. dissolved in almond oil can be encapsulated mixture.

In addition to essential oils, the liquid core may also contain adjuvants or agents capable of enhancing the properties of the essential oil, such as sesame oil containing components capable of enhancing the properties of the essential oil as a larvicide or an antibacterial agent. The amount of sesame oil or similar agent accounts for 2%-80% of the liquid core composition, but preferably 5%-60%. Sesame oil also acts as a synergistic additive to essential oils, enhancing the performance of essential oils by acting as a larvicide or antibacterial agent, beyond what it can achieve alone. It is known in the prior art that sesame oil can enhance the activity of various insecticides, but it has not been applied to essential oils nor encapsulated essential oils.

The size of the microcapsules comprising the polymeric spherical surface and the liquid core is from 0.05 mm to 2 mm in diameter, more preferably from 0.5 μm to 100 μm. In order to provide acceptable volatility and stability and controlled release at low cost, the proportion of polymer in the microcapsules is from about 5% to about 90% by weight, preferably from about 50% to about 85% by weight. For encapsulation and slow release of essential oils, the microcapsules have a size of at least about 0.05 μm to about 1000 μm, with microcapsules of about 20 μm to about 100 μm being particularly preferred.

Dispersion of the essential oil phase is preferably accomplished by stirring. Stirring is preferably reduced before adding the polyfunctional amine to the reaction mixture. Typical initial stirring rates are from about 500 rpm to about 2000 rpm, preferably from about 1000 rpm to about 1200 rpm. Fine tuning of the diameter can be achieved by controlling the agitation of the reaction mixture and the properties of the components in the aqueous solution.

In the process of manufacturing microcapsules, the water-insoluble essential oil dissolved in water-insoluble diisocyanate or polyisocyanate is dispersed in the water phase to form a water-insoluble phase, thereby forming a water-insoluble phase in the entire water phase A dispersion of liquid droplets; then, under stirring, polyfunctional amines and/or polyfunctional alcohols are added to the dispersion, whereby the amines and alcohols react with diisocyanates or polyisocyanates, thereby in the water-insoluble Polyurea and/or polyurethane shell walls are formed around the material of the microcapsules; in order to assist the suspension of the droplets in the aqueous phase, emulsifiers and/or suspending agents can be used to enhance the suspension of the microcapsules in the solution.

In the context of the present invention, polyisocyanates are generally understood to be those compounds which contain two or more isocyanate groups in the molecule. Preferred isocyanates are diisocyanates and triisocyanates, the isocyanate groups of which can be attached to aliphatic or aromatic moieties. The aliphatic polyisocyanate can be arbitrarily selected from aliphatic polyisocyanates containing two isocyanate functional groups, three isocyanate functional groups, or more than three isocyanate functional groups, or mixtures of these polyisocyanates. Preferably, the aliphatic polyisocyanate contains 5 to 30 carbon atoms. More preferably, the aliphatic polyisocyanate contains one or more cycloalkyl moieties. Examples of preferred isocyanates include dicyclohexylmethane 4,4'-diisocyanate; hexamethylene 1,6-diisocyanate; isophorone diisocyanate; trimethylhexamethylene diisocyanate; hexamethylene Trimer of 1,6-diisocyanate; trimer of isophorone diisocyanate; 1,4-cyclohexane diisocyanate; 1,4-(dimethylisocyanato)cyclohexane; hexamethylene urea of hexamethylene diisocyanate; trimethylene diisocyanate; propylene-1,2-diisocyanate; and butylene-1,2-diisocyanate. Mixtures of polyisocyanates can be used. Examples of suitable aliphatic diisocyanates and aliphatic triisocyanates are tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate and 4-(isocyanatomethyl)-1,8-octyl diisocyanate. Examples of aromatic polyisocyanates include 2,4-toluene diisocyanate and 2,6-toluene diisocyanate, naphthalene diisocyanate, diphenylmethane diisocyanate and triphenylmethane-p,p',p"-trityl Suitable aromatic isocyanates are toluene diisocyanate (TDI: DESMODUR Registered TM VL, Bayer); polymethylene polyphenyl isocyanate (MONDUR Registered TM MR, Miles Chemical Company); PAPI Registered TM135 (Dow Company); , 4,4'-diphenyl ether triisocyanate, 3,3'-dimethyl-4,4'-diphenyl diisocyanate, 3,3'-dimethoxy-4,4'-diphenyl diisocyanate, 1,5-naphthalene diisocyanate and 4,4',4"-triphenylmethane triisocyanate. A more suitable diisocyanate is isophorone diisocyanate. Adducts of diisocyanates with polyols such as ethylene glycol, glycerol, and trimethylolpropane are also suitable by dividing each mole of polyol with the number of moles of diisocyanates corresponding to the number of hydroxyl groups of the respective alcohols. Obtained by addition of isocyanates. In this way, multiple diisocyanate molecules are linked to polyols with carbamate groups to form macromolecular polyisocyanates. Another suitable product of this type (DESMODUR Registered™ L) can be prepared by reacting three moles of toluene diisocyanate with one mole of 2-ethylglycerol (1,1-dimethylolpropane). Suitable products are also obtainable by addition of hexamethylene diisocyanate or isophorone diisocyanate to ethylene glycol or glycerol. Preferred polyisocyanates are diphenylmethane-4,4'-diisocyanate and polymethylene polyphenylisocyanate. The above-exemplified diisocyanates and triisocyanates may be used alone or as a mixture of two or more of such isocyanates.

In a preferred embodiment, the polyisocyanate is polymethylene polyphenylisocyanate. These compounds are available under the trademark Mondur-MRS. The molar equivalent ratio of all primary amine or hydroxyl functional groups to isocyanate functional groups in the system is preferably about 0.8:1 to 1:1.2, more preferably about 1:1.1.

The polyfunctional amine can be any polyamine taught in the prior art for this purpose, and the amines used in the present invention are used to form the polyurea skin. Diamines or polyamines (such as ethylenediamine, phenylenediamine, toluenediamine, hexamethylenediamine. The polyfunctional amine can be any polyamine taught for this purpose in the prior art, particularly preferably It is diamine, triamine, tetramine or pentaamine. Such as ethylenediamine, diethylenetriamine, propylenediamine, tetraethylenepentamine, pentamethylenehexamine, etc.) exists in the water phase and organic/oil in phase. Suitable polyamines within the scope of the present invention are generally understood to be those compounds which contain in the molecule two or more primary amino groups which are linked to aliphatic or aromatic moieties. Examples of suitable aliphatic polyamines are α,ω-diamines including, but not limited to, ethylenediamine, propylene-1,3-diamine, tetramethylenepentamine, pentamethylenehexamine and 1,6 - Hexamethylenediamine and the like. A preferred diamine is 1,6-hexamethylenediamine.

Other suitable aliphatic polyamines are polyethyleneamines including, but not limited to, diethylenetriamine, triethylenetriamine, tetraethylenepentamine, pentaethylenehexamine.

Examples of suitable aromatic polyamines are 1,3-phenylenediamine, 2,4-toluenediamine, 4,4'-diaminodiphenylmethane, 1,5-diaminonaphthalene, 1,3,5 -Triaminobenzene, 2,4,6-triaminotoluene, 1,3,6-triaminonaphthalene, 2,4,4'-triaminodiphenyl ether, 3,4,5-triamino-1, 2,4-triazole, bis(hexamethylenetriamine) and 1,4,5,8-tetraaminoanthraquinone. These polyamines which are insoluble or not highly soluble in water can be used as hydrochlorides.

Compounds similar in structure to the above compounds but having one or more oxygen atoms present in ether linkages between carbon atoms may also be used. Preferably the hydrogen atoms are present on the amines, especially on the terminal amino groups. Aromatic diamines such as toluenediamine can be used. Mixtures of polyfunctional compounds can be used.

Other suitable polyamines are those polyamines which, in addition to amino groups, contain sulfo or carboxyl groups. Examples of such polyamines are 1,4-phenylenediaminesulfonic acid, 4,4'-diaminodiphenyl-2-sulfonic acid or diaminocarboxylic acids such as ornithine and lysine.

Such amino compounds may also contain anionic or cationic or amphoteric or hydrophilic groups which render the surface of the microcapsules of encapsulated essential oil anionic or cationic or amphoteric, or Water-based but uncharged.

The di- or polyhydroxyl compound which reacts with isocyanate to form urethane groups can be selected from, for example, ethylene glycol, diethylene glycol, propylene glycol, 1,4-butanediol, 1,4-hexanediol, dipropylene glycol, Polyols such as cyclohexyl-1,4-dimethanol and 1,8-octanediol, and polyols such as polyethylene glycol, polypropylene glycol, and polytetramethylene glycol with an average molecular weight of 200 to 2,000. Preferred crosslinkers are compounds containing more than 2 hydroxyl functions, such as trimethylolpropane, glycerol, hexane, triol and pentaerythritol. The crosslinking agent is used in an amount of 5% to 40% by weight, preferably 10% to 20% by weight, based on the diol. The aromatic hydroxy compound is selected from 1,3-dihydroxybenzene, 2,4-dihydroxytoluene, 4,4'-dihydroxydiphenylmethane, 1,5-dihydroxynaphthalene, 1,3,5-trihydroxy Benzene, 2,4,6-trihydroxytoluene, 1,3,6-trihydroxynaphthalene, 2,4,4'-trihydroxydiphenyl ether. Agents with hydroxyl groups that also contain carboxylic acid groups, sulfonic acid groups, phosphonic acid groups, and quaternary ammonium groups can also be used to make the surface of the microcapsules of encapsulated essential oils anionic or cationic or amphoteric, or uncharged. watery.

Catalysts can be added to essential oils or aqueous solutions to increase the reactivity of isocyanates with amines or hydroxyl groups. Catalysts suitable for use in the present invention are, for example, N,N-dimethylaminoethanol, N,N-dimethylcyclohexylamine, bis(2-dimethylaminoethyl)ether, N,N-di Amino compounds or organometallic compounds such as methylhexadecylamine, diaminobicyclooctane, stannous octoate, and dibutyltin dilaurate have a concentration of 0.1% to 0.3% by weight based on the glycol.

The catalyst may also be a metal salt, a tertiary amine, or the like. For example triethylamine or diethylmethylamine and metal salts of Cu, Pb, Zn, Co, Ni, Mn.

To form dispersions, emulsifiers such as sodium, potassium, magnesium, calcium or ammonium salts of lignosulfonic acid can be used.

The suspending agent capable of enhancing the suspension of the microcapsules in the solution is preferably a non-alkaline emulsifier selected from low-density polyvinyl alcohol and high-density polyvinyl alcohol or Tween 20, 40 or 80, And the suspending agent is selected from carboxymethylcellulose, sodium salt, xanthan gum, hickory (Karya) gum and locust bean gum.

Preferably, the non-alkaline emulsifier is selected from low-density polyvinyl alcohol and high-density polyvinyl alcohol or Tween 20, 40 or 80, and the suspending agent is selected from carboxymethyl cellulose, sodium salt, xanthan gum, mountain Walnut gum and locust bean gum.

Aqueous dispersions require surfactants. Preferred are nonionic surfactants. Examples of suitable surfactants include polyvinylpyrrolidone (PVP), polyvinyl alcohol (PVA) and poly(ethoxylated) nonylphenol. PVP is available with a molecular weight ranging from about 20,000 to about 90,000 and all such PVPs can be used, but PVP with a molecular weight of about 40,000 is preferred. Poly(ethoxy)nonylphenol is available under the trademark Igepal, the molecular weight of which varies according to the length of the ethoxy chain. Poly(ethoxy)nonylphenols can be used, but Igepal 630 (indicating a molecular weight of about 630) is the preferred poly(ethoxy)nonylphenol. Other examples of surfactants include polyether block copolymers, such as Pluronic.TM. and Tetronic.TM., polyethylene oxide adducts of fatty alcohols, such as Brij.TM. surfactants, and esters of fatty acids, such as stearate and oleate etc. Examples of the fatty acid include sorbitan monostearate, sorbitan monooleate, sorbitan sesquioleate, and the like. Examples of alcohol moieties of fatty esters include glycerol, glucosyl, and the like. Fatty esters are commercially available as surfactants from Arlacel C.RTM.

Surfactants vary in the nature of the surfactant and the nature of the surfactant can affect the size of the microcapsules formed. Other things being equal, the use of PVP with a molecular weight of 40,000 will result in larger microcapsules than Igepal 630. The surfactant used and the degree and intensity of agitation affect the size of the resulting microcapsules. Typically, their size is from about 1 μm to about 100 μm, depending on the conditions used.

Although less preferred, ionic surfactants can also be used. Mention may be made of partially neutralized salts of polyacrylic acid, such as sodium or potassium polyacrylate or sodium or potassium polymethacrylate.

As the water-insoluble solvent, nonpolar solvents that are inert to the encapsulation reaction but can dissolve or disperse the polyisocyanate and the material to be encapsulated can be used. Examples of suitable solvents include hydrocarbon solvents such as kerosene and alkylbenzenes such as toluene and xylene. It is preferred to use only small amounts of solvent; an amount of up to about 5% based on the amount of water is usually sufficient, and in most cases about 3% or less of solvent is preferred.

The reaction is readily carried out at room temperature, but it is preferred to operate below room temperature up to about 0°C, preferably about 15°C. It is possible in some cases to raise the reaction temperature up to 70°C, but the preferred temperature range is from 0°C to 30°C, most preferably below 20°C.

Microcapsules can be suspended in water to provide a suspension suitable for aircraft spraying. The suspension may contain a suspending agent, such as a colloidal suspending agent such as guar gum, rhamsan gum or xanthan gum.

However, it is also within the scope of the present invention to add light stabilizers, if desired. Suitable light stabilizers include the tertiary phenylenediamine compounds disclosed in Canadian Patent 1,179,682, the contents of which are incorporated by reference. It can be added by dissolving the light stabilizer together with the essential oil and polyisocyanate in a water-immiscible solvent. Alternatively, light stabilizers may be added to the polyurea shell as disclosed in Canadian Patent 1,044,134, the contents of which are incorporated by reference.

Capsules are prepared from various diisocyanates and polyisocyanates in a dispersed organic phase. Some of the isocyanate present reacts with water to form amines which can further react at the interface with the remaining isocyanate, which is then polymerized to form the polyurea shell. The aqueous phase also contains surfactants such as ethoxylated nonylphenols or polyethylene glycol ethers of linear alcohols. Additionally, the aqueous phase contains protective colloids, typically polyacrylates, methylcellulose, and polyvinyl alcohol (PVA). For example the particle size may be as small as 1 μm.

In a preferred embodiment of the invention, the encapsulation is carried out by dissolving the polyisocyanate (in a preferred case based on bisphenol A) in an essential oil in the presence of a polyamine and a diol or polyol (e.g. polyethylene glycol [PEG]) in water to emulsify the mixture. A preliminary reaction occurs which forms the film and results primarily in a polyurethane encapsulating coating with a small amount of urea groups formed by hydrolyzing the isocyanate with water and reacting the resulting amine with the remaining isocyanate groups. The final product contains only microcapsules dispersed in water without residual toxic chemicals. The solution does not require further purification and other substances can be added to form the final formulation.

A preferred material for incorporation into the encapsulating film during interfacial polymerization and/or as an adjuvant or additive in aqueous solutions is polyvinyl alcohol. Polyvinyl alcohol has been mentioned in the encapsulation of synthetic pesticides. For example, in U.S. Patent 5,925,464 (July 20, 1999, Mulqueen; Patrick Joseph; Smith; Geoff; Lubetkin; Steven D), recently assigned to Dow, small microencapsulated pesticides (such as chlorpyrifos) It is obtained by interfacial polycondensation reaction of PVA and polyamine (such as diethylenetriamine) with polyisocyanate (such as Voranate M220) used to make microcapsules for encapsulation. Microcapsules can be obtained which exhibit improved storage stability, in particular improved leaching of the active material from the resulting microcapsules, especially when the microcapsules are small in size (eg less than 5 μm).

As stated in said patent and incorporated into the present invention, "The encapsulation method in the presence of PVA during the encapsulation reaction has the advantage that the capsule wall can be controlled with a certain precision by varying the time before the addition of the polyamine. The amount of polyurethane and polyurea in the medium. Since these two polymers have completely different diffusivities to the encapsulating material, this polyurethane/polyurea ratio provides a useful method for controlling the activity, except by varying the capsule wall thickness and capsule size. Another independent method of the release rate of the substance. Another advantage of using PVA in the encapsulation reaction is that the PVA suspension formed on the surface of the microcapsule as a steric barrier can doewards during production or storage. ) aggregation and, when required, simultaneously enhance the efficacy of spray drying and the rapid dispersion of the dried product in water".

US Patent No. 4,417,916 discloses the encapsulation of water insoluble materials such as herbicides in polyurea shells. Using polyisocyanates and polyamines to form polyureas, the gist of the invention appears to be the use of lignosulfonate compounds as emulsifiers in the polyurea forming reaction. The concentration of water-insoluble material encapsulated in the exemplified examples ranges from 320 g/l composition to 520 g/l composition.

U.S. Patent No. 4,563,212 is similar to that taught by U.S. Patent No. 4,417,916, but uses emulsifiers other than lignosulfonates, particularly sulfonated naphthalene formaldehyde condensates and sulfonated polystyrene.

European patent EP 611 253 describes the reaction of polyisocyanates and polyamines using non-ionic surfactants (block copolymers containing hydrophilic and hydrophobic blocks) to encapsulate materials such as pesticides in poly in urea.

In one described embodiment, the polyamine in salt form is added to the isocyanate dispersion so that the polymerization is initiated by adding a base. This is said to improve the stability of behavior-altering compounds (aldehydes), but this was not exemplified.

In a preferred embodiment, the encapsulating material is a partially water-soluble material and the amount of encapsulated partially water-soluble material is at least 5%, preferably at least 90%, based on the total weight of the microcapsules.

In another aspect of the invention, the invention provides a microcapsule comprising a partially water-soluble organic material having a molecular weight greater than about 100 and less than about 400 and containing at least one heteroatom, the organic The material is encapsulated in a polyurea or polyurethane shell in an amount of at least 5%, preferably at least 9%, based on the total weight of the microcapsules.

The enclosing walls of the microcapsules are composed of polymers with varying degrees of porosity and pore size. The pore size and porosity can be varied using known methods, the pore size can vary from micron to submicron to nanoscale pores, and in one preferred application can be a relatively dense barrier where transport across the barrier is by "solution -Diffusion" mechanism is realized. The polymeric wall of the present invention may be selected from polymers such as polyurea, polyamine, polysulfonamide, polyester, polycarbonate or polyurethane, and constitute from about 5% to about 35% by weight of each microcapsule. Preferably, the microcapsule wall comprises from about 10% to about 25% by weight of the microcapsule.

The emulsifier is preferably selected from salts of lignosulfonic acid, such as its sodium, potassium, magnesium and calcium salts. Particularly effective are the sodium salts of lignosulfonic acid, referred to herein as lignosulfonate emulsifiers or surfactants.

In another embodiment of the invention, the preparation of microcapsules comprises an aqueous phase consisting of a solution containing a suitable emulsifier/crosslinking resin, optionally a stabilizer in the form of an antifoam agent, and optionally an antimicrobial agent. The emulsifier/crosslinking resin is preferably derived from a copolymerization product of styrene and maleic anhydride, or from a copolymerization product of styrene, maleic anhydride and alcohol. Copolymerization of styrene and maleic anhydride provides non-esterified copolymers or anhydride copolymers. When the copolymerization of styrene and maleic anhydride is carried out with an alcohol, the rings of the maleic anhydride are opened to form copolymers which are the half-acids and half-esters of the corresponding alcohols in the copolymerization reaction. Such alcohols include, but are not limited to, linear or branched lower C ₁ -C ₆ alkyl alcohols. Anhydride copolymers and half acid/half ester copolymers are further reacted with hydroxides such as ammonium hydroxide, sodium hydroxide, potassium hydroxide, magnesium hydroxide, calcium hydroxide, etc. to provide the aforementioned resins in the form of water-soluble salts. The aforementioned reaction of the hydroxide with the anhydride copolymer results in opening of the maleic anhydride ring to provide a disalt, such as a disodium or dipotassium salt. When the anhydride copolymer is reacted with, for example, ammonium hydroxide, the maleic anhydride ring opens to provide the amide/ammonium salt. In the context of the present invention, the emulsifier/crosslinking resin is preferably selected from ammonium hydroxide, sodium hydroxide, potassium hydroxide, magnesium hydroxide, calcium hydroxide salts of anhydrous copolymerization products of styrene and maleic anhydride; and Ammonium hydroxide, sodium hydroxide, potassium hydroxide, magnesium hydroxide, calcium hydroxide salts of half acid/half ester copolymerization products of styrene and maleic anhydride. Particularly preferred resins are the ammonium hydroxide and sodium hydroxide salts of the anhydrous copolymerization product of styrene and maleic anhydride, most preferably the ammonium hydroxide salt.

Can be added to the solution of microcapsules to improve shelf life and/or sprayability and/or properties such as adsorption to the substrate, said adjuvant can be selected from natural polymers and synthetic polymers, such as polyvinyl alcohol , polyvinylpyrrolidone, polyethylene oxide, ethylene/maleic anhydride copolymer, methyl vinyl ether-maleic anhydride copolymer, water-soluble cellulose, water-soluble polyamide or polyester, acrylic acid copolymer or homo polymers, water-soluble and modified starches, natural gums such as alginates, dextrins, and proteins such as gelatin and casein.

It will be appreciated that although the present invention is primarily directed to methods of preparing essential oil microcapsules, the present invention is also directed to essential oil microcapsules prepared by any of the methods of the invention described herein, and in particular to essential oil microcapsules prepared by any of the methods of the invention and Essential oil microcapsules for use in any of the following applications: Disinfectants for hard surfaces such as counter tops, ceramic tile, porcelain products (sinks and toilets), floors, windows, tableware, glassware, dishes, and dental and surgical appliances and cleaning compositions; fragrances and lotions for application to textile structures to improve skin physiology; antibacterial wipes for improved rapid bacterial reduction; long-lasting for Gram-negative and Gram-positive bacteria Antiseptic compositions; disinfectants and sanitizing compositions; spray creams in germicidal hard surface cleaning compositions; liquid cleaner compositions; antiseptic compositions having antiseptic, antiviral and larvicidal activity, e.g. Remedies for cold sores, head lice, vaginitis, warts, warts and athlete's foot and as antiseptic mouthwashes and surface cleaners; pediculicides; natural pesticides; flavoring agents; fragrances; Lice treatment composition; analgesic and anti-inflammatory composition; fragrance or insect repellent; active agent in pharmaceuticals and cosmetics; beneficial agent in extruded soaps and/or cleansing bars; food or tobacco additive; active in pharmaceuticals and cosmetics hair care products; and toothpastes containing encapsulated fragrances; mosquito, ant and insect repellents; larvicides; antivirals; antifungals; gels for gum disease; does not cause toxic syndrome female tampons; diapers.

Although the invention will be described in connection with preferred embodiments in the following examples so that its various aspects can be more fully understood and appreciated, the invention is by no means limited to these specific embodiments. On the contrary, the invention is intended to cover all such changes, modifications and equivalents as may be included within the scope of the invention as defined by the appended claims. Thus, the following examples, which include preferred embodiments, will serve to describe the practice of the invention, it being understood that the particulars shown are provided by way of example only for the purpose of illustrating and discussing the preferred embodiments of the invention and are provided The reason for this is to provide the most useful and understandable description of the formulation process and the principles and concepts of the invention.

Example

Example 1

Using composition 1 in Table 1, essential oil microcapsules were formed by interfacial polymerization as follows: 13.5 g of isocyanate was mixed with 88 g of eucalyptus oil and added to 347 g of water containing the amines EDA and DETA using a high shear mixer . Mixing was continued at room temperature for 2 hours then the dispersant Xanthane gum [Rodopol] (1.35 g) was added to obtain a stable emulsion and the pH adjusted to 7.0 as needed. The formulation was 100% lethal to larvae of Culex pipiens after one day at 500 ppm.

Example 2

Example 1 was repeated, except that Voronate M-580 was replaced by TDI [see Formulation 2 in Table 1], and the resulting microcapsules were not lethal at 500 ppm even after one day, showing that it is very important to choose materials for the manufacture of encapsulating formulations. important.

Example 3

Example 2 was repeated with pine oil [see formulation 3 in Table 1]. The yield of the obtained capsules was 78%, and the average size of the capsules was 100 μm.

Example 4

Example 1 was repeated with pine oil [see formulation 3 in Table 1]. The yield of the obtained capsules was 85%, and the average size of the capsules was 50 μm.

Example 5

Example 2 was repeated with pine oil [see formulation 5 in Table 1] with 3.4g TDI and 0.75g EDA and 0.68g DETA. The resulting capsules were 97% lethal to larvae of Culex pipiens after one day at 500 ppm.

Example 6

Example 5 was repeated except that TDI and 0.75g EDA and 0.68g DETA were replaced with pine oil having 4.4g Voronate M-580 [see formulation 6 in Table 1]. The resulting capsules were 97% lethal to larvae of Culex pipiens after one day at 500 ppm.

Example 7

Example 4 was repeated except that pine oil and Voronate M 580 and TEPA and HMDA were used instead of EDA and DETA [see formulation 7 in Table 1]. The resulting capsules were only 10% lethal to larvae of Culex acesmus after one day at 500 ppm.

Example 8

Example 7 was repeated using pine oil and replacing Voronate M-580 [see Formulation 8 in Table 1] with TDI. The resulting capsules were only 53% lethal to larvae of Culex acutinus after one day at 500 ppm.

Example 9

Example 4 was repeated except that pine oil and Voronate M 580 and PEG4000 were used instead of amines [see Formulation 9 in Table 1]. The resulting capsules were only 7% lethal to larvae of Culex acesmus after one day at 500 ppm.

Example 10

Example 9 was repeated except that Voronate M 580 was replaced by TDI [see Formulation 10 in Table 1]. The resulting capsules were 100% lethal to larvae of Culex amphipitus tested in 100 L buckets after one day at 500 ppm.

Example 11A

Example 10 was repeated with different concentrations of TDI and PEG 4000 [see Formulation 11 in Table 1]. The resulting capsules were 87% and 100% lethal after one day at 800ppm and 1000ppm, respectively, against larvae of Culex pipiens tested in a 100 L bucket. The lethality at a concentration of 1000 ppm was 87% and 80% after 14 days and 20 days, respectively.

Example 11B

When Example 11 was repeated using 500 ppm of partially quaternized tetraethylenepentamine, the resulting encapsulation formulation was 95% and 90% lethal to larvae of Culex acutina after 14 days and 20 days, respectively. Improved efficacy was shown for microcapsules with cationic surfaces.

Example 12A

When the packaged pine oil manufactured in Example 11 was tested in a 70L water pond, at a concentration of 800ppm, the average lethality of Culex acutus larvae in three different water ponds after 1, 7, 13 and 21 days The rates were 98%, 53%, 66% and 39%. Unencapsulated pine oil at the same concentration of 800 ppm had only 8% lethality after the first day and 0% thereafter. The lethality after 1 day and 7 days at 400 ppm was 93% and 43%, respectively.

Example 12B

When the pine oil capsules in Example 12A above also contained sesame oil [10% by weight of the total liquid core of pine oil and sesame oil], at a concentration of 800 ppm, after 1 day and 7 days, the encapsulated mixture was more effective than the three The average lethality of Culex acutinus larvae in the different pools was 93% and 89%, respectively. Non-encapsulated pine/sesame oils were 23% and 7% lethal after 1 and 7 days, respectively. This suggests that a mixture of pine oil and sesame oil can achieve significantly better results than sesame oil alone.

Example 13

Replace PEG 4000 with PEG 2000 and use higher concentration of TDI [see formula 12 in Table 1] to repeat embodiment 11, test in 70L water pool under 400ppm, the lethality rate to culex larvae larvae is 70%～ 73%. Unencapsulated pine oil was only 7% lethal at the same concentration of 400ppm.

Example 14

The above Example 1 was repeated with clove oil, and the encapsulation efficiency was 83%.

Example 15

The microcapsule essential oil preparation [see formulation 13 in Table 1] prepared in Example 11 with TDI and PEG 4000 is placed in a shallow 70L water bath, and after 1 day at a concentration of 800ppm, it is effective against Aedes aegypti (A.aegypti) Mosquito larvae and Culex acutus showed a killing effect of 90%, compared to only 10% for the unencapsulated essential oil as a control. These results can be compared with tests using other larvicides: for example, saponin extract from Quillaja saponaria was lethal to larvae of A. The rate is 100%. The activity against larvae was tested using cyromazine (an insect growth regulator) manufactured by Novartis, either directly or in encapsulated form. Cymethazin at an effective concentration of 0.5 g/ ^m2 gave 60% lethality after 3 days and the best sustained release formulation gave 100% lethality after 8 days.

Example 16

Microcapsules of eucalyptus oil were produced according to Example 2 and used under the condition of using a fiber softener, and had significant effect on two kinds of tested microorganisms (Staphylococcus aureus and Escherichia coli) at low temperature. disinfection effect. At a concentration of 0.8%, more than 99% of bacteria were killed. Concentration had a strong effect on efficacy: as the concentration of active ingredient increased from 0.2% to 0.8%, the number of microorganisms killed increased by a factor of 1 million. In comparison, oxycarbonates, which are currently used in Europe to replace chlorine-based disinfectants, have very limited efficacy against microorganisms at room temperature.

Example 17

Microcapsules of eucalyptus oil produced according to Example 1 and applied to brick walls at a concentration of 1.0 g per square meter of wall area (based on the weight of the essential oil) showed a low-temperature effect on two tested microorganisms (Vitis aureus coccus and E. coli) has a remarkable disinfecting effect - killing more than 95% of bacteria.

Example 18

Microcapsules of eucalyptus oil were produced according to Example 2 and applied to marble floors at a concentration of 0.8 g per square meter of floor area (based on the weight of the essential oil), showing a low-temperature effect on two tested microorganisms (Vitis aureus Cocci and E. coli) have a remarkable disinfecting effect - killing more than 90% of bacteria.

Table 1 Composition of materials used to form encapsulated essential oils serial number essential oil Isocyanate water Amine g Voronate M-580(DOW) ¹ g TDI ^2g g PEG2000 PEG4000 EDA DETA TEPA HMDA Dispersant 1 Eucalyptus oil 88g 13.5 347 3 2.7 Rodopol1.35g 2 Eucalyptus oil 88g 17.5 307 3 2.7 Rodopol1.35g 3 Pine oil 88g 13.5 347 3 2.7 Rodopol1.35g 4 Pine oil 88g 17.5 307 3 2.7 Rodopol1.35g 5 Pine oil 88g 3.4 362 0.75 0.68 Rodopol1.5g 6 Pine oil 88g 4.4 361 0.75 0.68 Rodopol1.5g 7 Pine oil 90g 17 370 3.2 2 JR-301.5g 8 Pine oil 90g 13.5 374 3.2 2 JR-301.5g 9 Pine oil 70g 13.2 262 JR-301.2g 10 Pine oil 70g 10.2 265 16.3 JR-301.2g 11 Pine oil 420g 61.2 1591 97.8 JR-301.5g 12 Pine oil 420g 88.7 1590 71 JR-308.2g 13 Pine oil 420g 61.2 1591 97.8 JR-4008.2g ¹ : Copolymer 4,4'-diphenylmethane diisocyanate ² : Toluene diisocyanate (Fluka) PEG = polyethylene glycol EDA = ethylenediamine DETA = diethylenetriamine TEPA = tetraethylene pentamine HMDA = hexamethylenediamine Rodopol = xanthan gum JR = cationic hydroxyethylcellulose polymer from Amerchol, Edison, NJ, USA

Example 19

In this example the use of encapsulated essential oils as mosquito repellants is illustrated.

Three essential oils, citronella oil, lavender oil and geranium oil, were prepared in a ratio of 1:1:1, and the mixture was dissolved in almond oil as a mixture of active ingredients to form a 24% solution of active ingredients ( Supplied by Tamar LTD of Israel under the trade name Di-Tush), encapsulated according to the above procedure with the following combinations. Thus, 153 g of Di-Tush with an active essential oil concentration of 24% was mixed with 19.8 g of TDI and dispersed in an aqueous solution of 270 g of water containing 2.7 g of PVA. After about 5 minutes, microcapsules of 32.3g PEG 4000 dissolved in 75g water were formed and continued to disperse, and finally at the end of the preparation, 2.4g Nefocide, 0.7g Rodopol and sodium dihydrogen phosphate were added. This formulation is referred to as N141. The results for 2 human volunteers are shown in Table 2.

Table 2 The relative efficacy of repellant #141 against Aedes aegypti within the 8-hour contact period (8:30～16:30) Repellant #141 Reduction rate (%) in the number of mosquito bites within 10 minutes in the mosquito cage for each hour of the 8-hour exposure period 1 2 3 4 5 6 7 8 Human Volunteer N1 94.3 91.7 84.1 77.9 78.4 78.3 77 Human Volunteer N2 100 100 96.3 96.7 93.5 92.3 90.1 average value 97.1 95.8 90.2 87.3 85.9 85.3 83.9

For each hour of the 8-hour test exposure period, the percent reduction in mosquito bites on the forearm of a human volunteer in a mosquito cage within 10 minutes was calculated according to the following formula: percent reduction=100*(C-T)/C where C is in The number of mosquito bites per hour on the forearm of human volunteers within 10 minutes in the untreated cage, T is the number of mosquito bites on the forearm of human volunteers per hour within 10 minutes in the treated cage times.

Example 20

Example 19 above was repeated to give an additional formulation #141 and another formulation #143 was prepared in the same manner using the 48% active Di-Tush formulation. Both formulations were tested on mice simultaneously with the commercially available synthetic repellent MO438E (29% active ingredient (a.i.)). The results are shown in Table 3. The results showed that both formulations had good mosquito repellency.

Table 3 The relative efficacy of repellant #141 against Aedes aegypti within the 8-hour contact period (8:30～16:30) repellant Reduction (%) in the number of mosquito bites received by the three treated mice during the 8-hour exposure 1 2 3 4 5 6 7 8 MO438E (20%ai) 100 98.8 100 100 100 100 100 98.9 #141(6%ai) 100 100 100 100 99.4 99.1 100 98.9 #143(6%ai) 100 100 100 100 100 100 100 98.9

The percentage reduction in the number of mouse bites from mosquitoes that landed on three mice in each hour of testing was calculated according to the following formula:

Percentage reduction = 100 x (C-T)/C

where C is the number of mosquitoes landed on three untreated control mice per hour in the untreated control cage and T is the number of mosquitoes landed on three treated mice per hour in the treated cage The number of mosquitoes that fell on the test mice.

It will be apparent to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, but that the invention may be embodied in other specific forms without departing from the essential characteristics of the invention. Accordingly, the embodiments and examples of the present invention should be considered illustrative and not restrictive in all respects. Refer to the appended claims rather than the foregoing description, and the claims should embrace all changes within the meaning and scope equivalent to the claims.

Claims (31)

1. method that is used to prepare essential oil microcapsules, described method comprises vulcabond or polyisocyanates is dissolved in the essential oil, the resulting mixture of emulsification in the aqueous solution that contains diamines or polyamines and/or dihydroxy compounds or polyol, around described essential oil drop, form polyureas and/or polyurethane film by interfacial polymerization, carry out the encapsulated of described essential oil thus, described film can strengthen described essential oil stability, reduce its evaporation rate and when being applied to substrate, control its rate of release.

2. the method for claim 1, wherein said polymerisation is carried out 0 ℃～30 ℃ temperature.

3. the method for claim 1, wherein said mixture also comprises catalyst.

4. the method for claim 1, wherein said aqueous solution also comprises dihydroxylic alcohols or polyalcohol, selectively comprises diamines or polyamines in addition.

5. the method for claim 1, wherein said aqueous solution also comprises at least a emulsifying agent.

6. the method for claim 1, wherein said essential oil is encapsulated with being selected from adjuvant and can strengthening other composition of reagent of described essential oil performance.

7. method as claimed in claim 6, wherein said other composition is a sesame oil.

8. the method for claim 1, wherein said essential oil is selected from cottonseed oil, soybean oil, cinnamon oil, corn oil, cedar oil, castor oil, caryophyllus oil, geranium oil, lemongrass oil, Linseed oil, peppermint oil, sesame oil, thyme linaloe oil, rosemary oil, oleum anisi, basil, camphorated oil, citronella oil, eucalyptus oil, fennel oil, oil of grapefruit, lemon oil, tangerine oil, orange oil, pinke needle oil, papper oil, attar of rose, tangerine oil, tea oil, camellia seed oil, caraway oil, garlic oil, sesame oil, onion oil, rosemary oil, citronella oil, lavender oil, geranium oil, apricot kernel oil, spearmint oil and their mixture.

9. the method for claim 1, wherein said encapsulatedly carry out as follows: under environmental condition, polyisocyanates is dissolved in the described essential oil, the mixture of emulsification gained in the aqueous solution that contains polyamines and/or dihydroxylic alcohols or polyalcohol, initial reaction has wherein taken place, described initial reaction has formed film and has consumed whole existing polyamines, the slower polyalcohol of reaction reacts and forms outside crosslinked coating then, water further consumes the isocyanates of any remnants, with the amine of formation with the isocyanate reaction of any remnants.

10. method as claimed in claim 9 does not exist diamines or polyamines in the wherein said aqueous solution.

11. method as claimed in claim 9, wherein said method is carried out 0 ℃～30 ℃ temperature.

12. the method for claim 1, wherein said vulcabond or polyisocyanates be selected from dicyclohexyl methyl hydride 4,4 '-vulcabond; Hexa-methylene 1, the 6-vulcabond; IPDI; Trimethyl hexamethylene diisocyanate; Hexa-methylene 1, the trimer of 6-vulcabond; The Trimerization of Isophorone Diisocyanate thing; 1, the 4-cyclohexane diisocyanate; 1,4-(dimethyl NCO) cyclohexane; The biuret of hexamethylene diisocyanate; The urea of hexamethylene diisocyanate; Trimethylene diisocyanate; Propylidene-1,2-vulcabond and butylidene-1,2-vulcabond; The mixture of aliphatic diisocyanate and aliphatic triisocyanate, as tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate and 4-(isocyanates ylmethyl)-1,8-octyl group vulcabond, aromatic polyisocyanate, comprise 2,4-toluene di-isocyanate(TDI) and 2, the 6-toluene di-isocyanate(TDI), naphthalene diisocyanate, methyl diphenylene diisocyanate and triphenyl methane-p, p ', p " trityl triisocyanate; suitable aromatic isocyanate is as toluene di-isocyanate(TDI); polymethylene polyphenyl isocyanate; 2,4; 4 '-the diphenyl ether triisocyanate; 3,3 '-dimethyl-4,4 '-diphenyl diisocyanate, 3,3 '-dimethoxy-4 ', 4 '-diphenyl diisocyanate, 1,5-naphthalene diisocyanate and 4,4 ', 4 " triphenylmethane triisocyanate and IPDIs.

13. the method for claim 1, wherein said diamines or polyamines are selected from ethylenediamine, diethylentriamine, propane diamine, tetren, the pentamethylene hexamine, α, ω-diamines, propylidene-1, the 3-diamines, tetra-methylenedimine, five methylene diamine and 1, the 6-hexamethylene diamine, polyvinylamine, diethylentriamine, three ethylene triamines, penten, 1, the 3-phenylenediamine, 2, the 4-toluenediamine, 4,4 '-diaminodiphenyl-methane, 1, the 5-diaminonaphthalene, 1,3, the 5-triaminobenzene, 2,4,6-triamido toluene, 1,3,6-triamido naphthalene, 2,4,4 '-the triamido diphenyl ether, 3,4,5-triamido-1,2, the 4-triazole, two (hexa-methylene triamines) and 1,4,5, the 8-tetra-amino anthraquinone.

14. method as claimed in claim 4, wherein said dihydroxylic alcohols or polyalcohol are selected from such as ethylene glycol, diethylene glycol, propane diols, 1, the 4-butanediol, 1, the 4-hexylene glycol, DPG, cyclohexyl-1, the 4-dimethanol, 1, polyalcohols such as 8-ethohexadiol, with mean molecule quantity be 200～2000 such as polyethylene glycol, polypropylene glycol, polyalcohols such as polytetramethylene glycol, trimethylolpropane, glycerine, hexanetriol and pentaerythrite, 1, the 3-dihydroxy benzenes, 2, the 4-orcin, 4,4 '-the dihydroxy diphenyl methane, 1, the 5-dihydroxy naphthlene, 1,3, the 5-trihydroxy benzene, 2,4, the 6-trihydroxytoluene, 1,3, the 6-trihydroxynaphthalene, 2,4,4 '-trihydroxy diphenyl ether and polyvinyl alcohol.

15. method as claimed in claim 3, wherein said catalyst is selected from: such as N, N-dimethylaminoethanol, N, N-dimethylcyclohexylam,ne, two (2-dimethyl aminoethyl) ether, N, amino-compound or organo-metallic compounds such as N-dimethyl cetylamine, diaminourea bicyclooctane, stannous octoate and dibutyl tin laurate, its concentration is 0.1 weight %～0.3 weight % based on dihydroxylic alcohols, and such as the slaine of tertiary amines such as triethylamine or diethylmethyl amine and Cu, Pb, Zn, Co, Ni, Mn.

16. the method for claim 1, wherein, to prevent or reduce that the composition that is selected from emulsifying agent, suspending agent or steric barrier polymers that microcapsule granule is assembled is added in the aqueous solution that is dispersed with blend of essential oils, described composition is selected from sodium salt, sylvite, magnesium salts, calcium salt or the ammonium salt of lignosulfonates; The pure and mild high-density polyethylene enol of low density polyethylene (LDPE) or polysorbas20,40 or 80, carboxymethyl cellulose, sodium salt, xanthans, hickory nut glue and locust bean gum, polyvinylpyrrolidone (PVP), water-soluble poval (PVA) and poly-(ethyoxyl) nonyl phenol, polyether block copolymer, the polyethylene oxide adduct of fatty alcohol and the ester of aliphatic acid.

17. the method for claim 1, wherein resulting microcapsules comprise 60%～95% essential oil, and the remainder of described microcapsules is made of capsule wall and additive.

18. the method for claim 1, wherein the average-size of resulting microcapsules is 10 μ m～100 μ m.

19. the method for claim 1, wherein resulting microcapsules contain the essential oil as larvicide, described microcapsules are of a size of 0.5 μ m～100 μ m, and be suitable for swimming on the water surface, can do not degraded, and can slowly discharge wherein the essential oil agricultural chemicals of being encapsulated in of effective dose by ultraviolet radiation.

20. the method for claim 1, wherein resulting microcapsules contain essential oil, described microcapsules are of a size of 0.5 μ m～100 μ m, and be suitable for swimming on the water surface, can do not degraded, and can slowly discharge wherein the essential oil larvicide of being encapsulated in of effective dose by ultraviolet radiation.

21. the method for claim 1, wherein resulting microcapsules contain essential oil, and institute's microcapsules are of a size of 0.5 μ m～100 μ m, and can slowly discharge wherein the essential oil pest repellant of being encapsulated in of effective dose.

22. the method for claim 1, wherein resulting microcapsules contain essential oil, and described microcapsules are of a size of 0.5 μ m～100 μ m, and can slowly discharge wherein the essential oil culicifuge of being encapsulated in of effective dose.

23. the method for claim 1, wherein resulting microcapsules contain by be dissolved in the apricot kernel oil by mixed essential oil that citronella oil, lavender oil and geranium oil constituted, described microcapsules are of a size of 0.5 μ m～100 μ m, and can slowly discharge wherein the essential oil culicifuge of being encapsulated in of effective dose.

24. the method for claim 1, wherein resulting microcapsules contain the essential oil as pest repellant, and described microcapsules are of a size of 0.5 μ m～100 μ m, and can slowly discharge wherein the pest repellant of being encapsulated in of effective dose.

25. as each described method of claim 21～24, wherein said microcapsules have reduced the amount of the encapsulated essential oil of degrading because of ultraviolet ray or oxidation.

26. the method for claim 1, wherein resulting microcapsules contain in the consumer goods essential oil as the substitute of chlorine-containing disinfectant, and have lasting antibacterial activity when described microcapsules are used in hard surface cleaner, laundry detergent compositions and the softening agent.

27. the method for claim 1, wherein said microcapsules after formation with reactive amines or contain the reagent reacting of hydroxyl, described reactive amines or the reagent that contains hydroxyl also contain anionic group or cation group or amphiprotic group or hydrophilic radical, described group makes the surface of the microcapsules of encapsulated essential oil have anionic property or cationic or both sexes, or possess hydrophilic property but neutral.

28. the method for claim 1, wherein said microcapsules carry out post-modification by absorbing monomer or polymer in its surface after formation, described monomer or polymer can increase their hydrophily or hydrophobicity, or make their surface have anionic property or cationic or both sexes or possess hydrophilic property but neutral.

29. the method that is used to form essential oil microcapsules as claimed in claim 1, wherein said microcapsules are suitable for use as antivirotic and antifungal agent.

30. method as claimed in claim 8, wherein said essential oil are the oil outside ginger oil, cottonseed oil or its mixture.

31. an essential oil microcapsules, this essential oil microcapsules prepares with each described method of claim 1～30.