JPH09911A - Production of dispersion of microcapsule housing volatile matter and production of microcapsule housing volatile matter - Google Patents

Abstract

PURPOSE: To produce a dispersion of microcapsules excellent in property of slowly releasing a housed volatile matter and capable of releasing the volatile matter over a long period of time. CONSTITUTION: An oily liq. contg. a volatile matter, a multifunctional isocyanate, a water-insoluble polyol and an organotin compd. is added to an aq. liq. contg. a polyamine having at least two amino groups and an emulsifier, and the oily liq. is emulsified, dispersed and brought into a resinification reaction to obtain the objective dispersion of microcapsules each consisting of a gelatinous polyurethane resin core 1 contg. the volatile matter and a polyurea resin shell 2 formed on the periphery of the core 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a process for producing microcapsules containing a volatile substance, which is excellent in sustained release of the volatile substance and can exert a long-term medicinal effect.

[0002]

2. Description of the Related Art Conventionally, a microcapsule containing a volatile substance has a remarkable release of the volatile substance contained therein even at room temperature. However, there is a problem in that the amount of emission decreases. Further, there is a problem that the storage period of the microcapsules is extremely short because the retention of the encapsulating volatile substance is insufficient when not in use.

Therefore, various microcapsules have been tried in order to improve the retention of volatile substances. For example, in JP-A-2-145383, a fragrance,
A volatile substance such as an insecticide has a glass transition temperature of 50 to 200.
Microcapsules encapsulated using a wall film at ℃ have been proposed. The microcapsules have a wall film of polyurethane or polyurea and are manufactured as follows. That is, a polyfunctional isocyanate was dissolved in a volatile substance serving as a core substance or a hydrophobic medium containing the volatile substance, and this was emulsified and dispersed in an aqueous medium to which an emulsifier and optionally a polyamine or a polyol were added. Then, it is produced by raising the temperature of the system and reacting at the oil drop interface.

[0004]

However, the microcapsules containing a volatile substance obtained by the above-mentioned production method are still insufficient in retention of the volatile substance as a core substance, and thus are satisfactory in terms of sustained release. Not a decent one,
There is a problem that the volatile substance cannot exert its medicinal effect over a long period of time.

In Japanese Patent Publication No. 42-771, hexamethylenediamine is dissolved in water to form an aqueous phase.
A method for producing microcapsules by adding an isocyanate component and castor oil to one oil phase is described. However, in this method, before the isocyanate component reacts with castor oil, it reacts with hexamethylenediamine in the aqueous phase, and castor oil is used as the core substance, that is, microcapsules containing only castor oil are included. Manufactured. With such a method, it is not possible to manufacture microcapsules containing a volatile substance.

[0006] The present invention is a method for producing a microcapsule dispersion liquid containing a volatile substance and a volatile substance-containing microcapsule which are excellent in sustained release of the volatile substance to be encapsulated and can release the volatile substance over a long period of time. The purpose is to provide.

[0007]

In order to achieve the above object, the present invention provides a volatile substance in which the following liquid (A) is added to the following liquid (B) to emulsify and disperse the resin to cause a resinification reaction. The first gist is the method for producing the encapsulated microcapsule dispersion. (A) An oily liquid containing the following components (a) to (d). (A) Volatile substance. (B) Polyfunctional isocyanate. (C) Water-insoluble polyol. (D) Organotin compound. (B) An aqueous liquid containing the following components (e) and (f). (E) A polyvalent amine having at least two amino groups. (F) an emulsifier.

Further, the above liquid (A) is added to the above liquid (B) to emulsify and disperse it, and to carry out a resinification reaction to form a volatile substance-encapsulating microcapsule dispersion liquid. The second gist is a method for producing volatile substance-containing microcapsules from which microcapsules are taken out.

[0009]

The present inventors have conducted a series of studies in order to obtain microcapsules which are excellent in sustained release and which can be released over a long period of time by suppressing the amount of volatile substances contained in the microcapsules. . In the process of its research, it is difficult to obtain long-term release of the volatile substance by means of improving the function of the shell itself that encapsulates the volatile substance in the microcapsule having the core-shell structure. I got the knowledge. Based on this finding, if the core, which contains the volatile substance instead of the shell, is composed not only of the volatile substance but of a solid containing the volatile substance or a substance having a property close to that of the volatile substance, Based on the idea that the sustained release of the active substance could be improved, further research was conducted centering on the structure of the core. As a result, an oily liquid (A liquid) containing an organotin compound is converted into an aqueous liquid (B liquid) containing a polyvalent amine having at least two amino groups and an emulsifier.
When it is added to and emulsified and dispersed in the aqueous liquid, the polyfunctional amine is contained in the aqueous liquid. Therefore, at the oil drop interface, the polyfunctional isocyanate (b component) in the A liquid and the polyfunctional amine (e
Component) reacts extremely rapidly to form a shell part made of polyurea resin, and later, due to the catalytic action of the organotin compound (d component), the polyfunctional isocyanate (b component) and the water-insoluble polyol (c component). ) Reacts with each other to start gelation inside the shell to form a gel-like polyurethane resin core containing a volatile substance (a component), and a core made of the above-mentioned volatile substance-containing gel-like polyurethane resin. The inventors have found that a special volatile substance-encapsulating microcapsule in which a part is covered with a shell is obtained, and the present invention has been accomplished. The volatile substance-encapsulated microcapsules thus obtained have a core composed of a gel polyurethane resin, and the volatile substance contained in the microcapsules has an excellent sustained release property because the release amount from the core is suppressed. Have.

In the process for producing such a special volatile substance-encapsulating microcapsule, when the above oily liquid (Liquid A) does not contain a solvent, the volatile substance-encapsulating microcapsule having a better sustained release can be obtained. become.

When silicon dioxide and cyclodextrin are added to the above-mentioned oily liquid (Liquid A) alone or in combination, the volatilization of the volatile substance is further excellent due to the action of inclusion of the volatile substance. A microcapsule containing a sexual substance can be obtained.

Examples of the volatile substance (a component) include pesticides, fragrances, and plant essential oils. Particularly, it is effective to use allyl isothiocyanate from the viewpoint of sustained release.

Next, the present invention will be described in detail.

In the method for producing a volatile substance-encapsulated microcapsule dispersion of the present invention, a specific oily liquid (A liquid) and a specific aqueous liquid (B liquid) to which this oily liquid is added and emulsified and dispersed are used. To be

First, the specific oily liquid (liquid A) will be described.

The oily liquid (A liquid) is a volatile substance (a component), a polyfunctional isocyanate (b component), a water-insoluble polyol (c component), and an organotin compound (d component).
Obtained using and.

The volatile substance (component a) is not particularly limited as long as it has volatility at room temperature, regardless of the melting point and boiling point of the substance. Specific examples include pesticides, fragrances and plant essential oils.

Examples of the above-mentioned pesticides are dimethyl-2,2-dichlorovinyl phosphate (DDVP), o, o-dimethyl-o- (3-methyl-4-nitrophenyl) thiophosphate, dimethyldicarbetoxyethyldithiophosphate and the like. And organic phosphorus insecticides, methyl isothiocyanate, methyl bromide, kunponic agents such as chloropicrin, and attractants such as turpentine oil and pinene oil.

Examples of the above-mentioned fragrances include various natural fragrances and synthetic fragrances, and as the raw materials thereof, for example, bouquet, rose oil, green floral, eucalyptus oil, lavender oil, jasmine, lemon oil,
Various herbs etc. can be mentioned.

As the above-mentioned plant essential oil, those having a medicinal effect, for example, hinoki oil, hiba oil, allyl isothiocyanate, cedar oil, moon peach oil, citrus oil,
Examples include ginger oil. Among these, as the volatile substance used in the present invention, it is effective to use allyl isothiocyanate from the viewpoint of sustained release.

The volatile substance (a component) may be used as it is, or may be used by being contained in a hydrophobic medium. It is preferable to use the volatile substance as it is, from the viewpoint that more excellent sustained release property can be obtained.

Further, by using silicon dioxide and cyclodextrin alone or in combination with the volatile substance, more excellent sustained release property can be obtained. It is considered that this is due to the inclusion action of the volatile substance. When the above silicon dioxide and cyclodextrin are used, the compounding amount is 0.5 based on the total amount of the oily liquid (A liquid).
It is preferably set within the range of 20 wt% (hereinafter abbreviated as “%”). It is particularly preferably 1 to 10%. That is, if the content is less than 0.5%, it is difficult to obtain a more excellent effect of improving sustained release, and conversely, if the content exceeds 20%, it tends to be difficult to produce volatile substance-containing microcapsules. This is because that.

The above-mentioned hydrophobic medium is used as a volatility inhibitor for volatile substances, and examples thereof include esters such as benzyl benzoate and dioctyl phthalate, and vegetable oils such as mineral oils and cottonseed oils. Further, in addition to these, various auxiliaries such as an antioxidant, an ultraviolet absorber and a colored dye can be appropriately added, if necessary.

Examples of the polyfunctional isocyanate (component b) used together with the component a include phenylene diisocyanate, tolylene diisocyanate, hexamethylene diisocyanate, diphenylmethane diisocyanate, naphthalene diisocyanate, xylylene diisocyanate, polymeric diphenylmethane diisocyanate, isophorone diisocyanate, triphenyl. Examples thereof include methanetriisocyanate and the like, and isocyanurate-modified and buret-modified products of the above polyfunctional isocyanates, and isocyanate prepolymers which are addition products with polyols such as trimethylolpropane and hexanetriol. These may be used alone or in combination of two or more.

Examples of polyols other than trimethylolpropane and hexanetriol include aliphatic polyols such as ethylene glycol, propylene glycol and hexanediol, aromatic polyols such as xylylene glycol, polyhydric phenols such as hydroquinone and catechol, and the like. Examples thereof include condensates of polyhydric phenols and alkylene oxides, polyol prepolymers such as polyester polyols and polyether polyols. These may be used alone or in combination of two or more. Among these polyols, trimethylolpropane is preferably used from the viewpoint that volatile substance-containing microcapsules excellent in sustained release can be obtained.

The polyfunctional isocyanate (b
Among the components), it is preferable to use hexamethylene diisocyanate and isophorone diisocyanate from the viewpoints of obtaining non-yellowing type volatile substance-containing microcapsules and being economical.

Specific examples of the water-insoluble polyol (component c) used together with the components a and b include castor oil, polyoxyalkylene polyols, polyether polyols such as polytetramethylene ether glycol, and condensed polyester polyols. And polyester polyols such as lactone polyester diol and polycarbonate diol. These may be used alone or in combination of two or more. Of these water-insoluble polyols, castor oil is preferably used from the viewpoint of reactivity and sustained release. The amount of the water-insoluble polyol (component c) to be blended is preferably set to 10 to 300 parts, and particularly preferably, to 100 parts by weight of the polyfunctional isocyanate (component b) (hereinafter abbreviated as “part”). It is 50 to 200 parts. When the amount of the water-insoluble polyol (component c) is less than 10 parts or more than 300 parts, that is, when the amount is outside the above range, the target core portion is a gel-like volatile substance-encapsulating microcapsule. It tends to be difficult to obtain.

It is necessary to use those water-insoluble polyols (component c) having at least two hydroxyl groups. That is, if the number of hydroxyl groups is one, the core is not in a gelled state without crosslinking. In addition, when a polyol that dissolves in water is used, it is difficult to form microcapsules, which is not suitable for use. From this point of view, the above water-insoluble polyol (component c) is used. Then, in the reaction between the water-insoluble polyol (component c) and the polyfunctional isocyanate (component b), the reaction between the two becomes extremely fast without the addition of the organotin compound (d component) described below. It is not preferable in the subsequent operation, and in consideration of this point, the water-insoluble polyol (component c) is appropriately selected.

Further, examples of the organotin compound (d component) used together with the above components a to c include, for example, tri-
Examples thereof include n-butyltin acetate, n-butyltin trichloride, dimethyltin dichloride, dibutyltin dilaurate and trimethyltin hydroxide. These organotin compounds (d component) may be used as they are, or may be used in a solvent such as ethyl acetate at a concentration of 0.1 to 2
You may melt | dissolve so that it may become 0%, and it may be added so that it may become 0.01-1 part as solid content with respect to 100 parts of polyfunctional isocyanate (b component) which is an isocyanate component in an oily liquid. Thus, the compounding amount of the organotin compound (d component) is 0 as a solid content based on 100 parts of the polyfunctional isocyanate (b component), either as it is or when it is dissolved in a solvent. .01-
It is preferably set to 1 part, and particularly preferably 0.05 to 0.5 part. That is, if the compounding amount of the organotin compound (d component) is too small, such as less than 0.01 part, most of the polyfunctional isocyanate (b component) is used for forming the shell part, and Difficult to form. On the other hand, if the amount exceeds 1 part, the formation of the core becomes extremely fast, and it tends to be difficult to obtain the desired volatile substance-containing microcapsules. Then, in the oily liquid (Liquid A), the reaction of the water-insoluble polyol (component c) and the polyfunctional isocyanate (component b) is initiated by the catalytic action of the organotin compound (component d), but the reaction is extremely extreme. It is necessary to adjust the blending amount of the organotin compound (d component) so as not to accelerate the process.

In the oily liquid (A liquid) containing the above components a to d, the solvent and volatile substance (volatile substance) present in the isocyanate component which is the polyfunctional isocyanate (component b) are contained. When the solvent such as the hydrophobic medium containing the component a) is not contained, the sustained release property of the volatile substance contained therein becomes excellent. Since the amount of the solvent used for adding the organotin compound (d component) is small, sustained release is not significantly affected. The more excellent sustained-release property without containing the solvent is that the polyurethane having an excellent three-dimensional cross-linking structure is obtained without inhibiting the reaction between the polyfunctional isocyanate (b component) and the water-insoluble polyol (c component). It is considered that this is because the resin is formed.

Next, the aqueous liquid (B liquid) to which the above specific oily liquid (A liquid) is added and emulsified and dispersed will be described.

The above aqueous liquid (B liquid) contains a polyvalent amine having at least two amino groups (component e) and an emulsifier (f).
Component) and.

The polyvalent amine (component e) has at least two amino groups, and examples thereof include ethylenediamine, hexamethylenediamine, phenylenediamine, tolylenediamine and diethylenetriamine. Among them, ethylenediamine is preferably used from the viewpoints of economy and curability of the surface of the microcapsule containing a volatile substance. The polyvalent amine (e component)
It is preferable to set the blending ratio of 0.1 to 10% of the total amount of the aqueous liquid (B liquid). It is particularly preferably 0.1 to 6%. That is, if the compounding ratio of the polyvalent amine is less than 0.1%, it is difficult to suppress the volatilization of the volatile substance, and if it exceeds 10%, it tends to be difficult to produce the volatile substance-containing microcapsules. Because it will be done.

By adding the polyvalent amine (component (e)), the reaction between the polyvalent amine and the polyfunctional isocyanate (component (b)) in the oily liquid (component A) causes the oily liquid (component A) to react. The water-insoluble polyol (component (c)) in () and the polyfunctional isocyanate (component (b)) react faster. Therefore, regarding the formation of the core-shell structure microcapsules, first, the polyurea resin of the shell is formed at the interface of the oil droplets, and thereafter, inside the shell, the volatile substance (a Since a gel polyurethane resin containing the component) is formed, volatile substance-encapsulating microcapsules having a special structure can be obtained.

As the emulsifier (component f) used together with the polyvalent amine (component e), anionic, cationic, nonionic and amphoteric water-soluble polymer substances and various surfactants can be used.

Examples of the anionic polymer substance include natural polymers such as gum arabic and alginic acid, semi-synthetic polymers such as carboxymethyl cellulose, sulfated cellulose and phthalated gelatin, carboxy modified polyvinyl alcohol, styrene sulfonic acid type polymers. And synthetic polymers such as copolymers and maleic anhydride copolymers.

Examples of the cationic polymer substance include cationized starch and the like.

Examples of the nonionic polymer substance include polyvinyl alcohol, methyl cellulose, hydroxyethyl cellulose, xanthan gum, and the like, and examples of the amphoteric polymer substance include gelatin.

Further, as the above various surfactants, anionic surfactants such as sodium lauryl sulfate, sodium laurylbenzene sulfonate, sodium polyoxyethylene alkylphenyl ether sulfate, polyoxyethylene alkyl ether, polyoxyethylene alkylphenyl, etc. Examples thereof include nonionic surfactants such as ethers, cationic surfactants such as alkyltrimethylammonium salts, and amphoteric surfactants such as alkylbetaine type and alkylimidazoline type surfactants.

These emulsifiers (component f) are generally prepared by adding them to water so that the concentration of the aqueous solution is 1 to 20%.

The volatile substance-containing microcapsule dispersion of the present invention is produced, for example, as follows.
That is, a specific oily liquid (A
Solution). In addition, the aforementioned e component and f component are added to water to prepare an aqueous liquid (B liquid) having a predetermined concentration. Then, the prepared oily liquid (A liquid) is added to the aqueous liquid (B liquid)
And emulsified and dispersed by stirring at high speed, and then continuing the reaction by stirring at low speed. By reacting at the oil drop interface and inside in this way, a core-shell structure in which the core is covered with a shell is formed, and the core is formed of a gel polyurethane resin containing a volatile substance. A special volatile substance-encapsulating microcapsule dispersion liquid in which the shell portion is formed of a polyurea resin is manufactured. Subsequently, the volatile substance-encapsulating microcapsules are obtained by separating the water content from the dispersion by a predetermined method.

In the volatile substance-encapsulated microcapsule dispersion liquid obtained as described above, the content of the volatile substance-encapsulated microcapsules in the dispersion liquid is used by coating, spraying and impregnating various base materials described below. The expected medicinal effect,
In consideration of the sustained release property, it is preferable to set it in the range of 2 to 70% in the dispersion liquid.

The mixing ratio of the oily liquid (Liquid A) and the aqueous liquid (Liquid B) is 0.5 by weight with respect to 1 of the oily liquid.
It is preferable to set it to be -50. Particularly preferably, the aqueous liquid is 0.8 to 1.5 with respect to 1 oily liquid.
That is, when the amount of the aqueous liquid is less than 0.5 with respect to the oily liquid, it is difficult to make water the continuous phase. In addition, the aqueous liquid is 50
If it exceeds, the tendency tends to be that only a product having a too low concentration of the volatile substance-encapsulating microcapsules can be obtained.

It is preferable that the stirring condition by high speed rotation for emulsification and dispersion is set to 1000 to 2000 rpm, and the stirring condition by low speed rotation is set to 100 to 500 rpm. As a stirrer used for stirring such as emulsion dispersion, for example, a high speed dissolver type mixer (auto homomixer, homodisper, etc.) is used.

Further, the above reaction conditions are set at 20 to 40 ° C. for a short time of about 0.5 to 2 hours. The special volatile substance-encapsulating microcapsules as described above can be obtained in a shorter time and at a lower temperature as compared with the conventional case.

The method of separating water from the volatile substance-encapsulated microcapsule dispersion to obtain the volatile substance-encapsulated microcapsules is not particularly limited, and a conventionally known method such as a centrifugation method is used. , A pressure filtration method, a vacuum suction filtration method and the like. Furthermore, the volatile substance-containing microcapsules obtained by the above separation may be appropriately dried by a conventionally known method, for example, heat drying, spray drying, vacuum drying, freeze drying, or the like.

As described above, the present inventors have speculated as to the formation mechanism for obtaining a special volatile substance-encapsulating microcapsule, from the findings obtained through a series of studies on microcapsules. That is, due to the presence of the polyvalent amine (e component) having at least two amino groups, which is added to the above aqueous liquid (B liquid), the oil liquid (A
When the liquid) is added to the aqueous liquid (liquid B) and stirred, the polyfunctional isocyanate (b component) and the polyamine (e) in the oil liquid (liquid A) are generated at the oil droplet interface rather than the internal gelation reaction. Reacts very quickly with (component). Therefore, in the formation of the core-shell structure microcapsules, first, the polyurea resin is reacted to form the shell portion, and after a while, gelation of the polyurethane resin containing the volatile substance which becomes the core portion is delayed. It is thought to begin. This gelling reaction is due to the reaction between the water-insoluble polyol (component c) and the polyfunctional isocyanate (component b).

A schematic view of the volatile substance-containing microcapsules thus obtained is shown in FIG. As shown,
It has a core-shell structure in which the outer periphery of a gel polyurethane resin 1 containing a volatile substance as a core is covered with a shell 2 made of polyurea resin. The particle size of the volatile substance-encapsulating microcapsules is not particularly limited, but is generally set in the range of 0.5 to 500 μm.

In the volatile substance-containing microcapsules obtained by the production method of the present invention, it is confirmed by observing the cross section of the obtained volatile substance-containing microcapsules with an electron microscope that the core is in a gel state. can do. In addition, using the obtained volatile substance-encapsulating microcapsules, residual water-insoluble polyol (component c) depending on the solvent
As a result of carrying out the extraction operation of the above, it is judged that the water-insoluble polyol (component c) cannot be obtained, so that the water-insoluble polyol completely reacts with the polyfunctional isocyanate and the inside is in a gel state. . Furthermore, with volatile substances,
Polyfunctional isocyanate, water-insoluble polyol,
It is inferred from the fact that when the catalyst is mixed at 20 to 40 ° C. and left for 0.5 to 2 hours, it loses fluidity and becomes in a gel state.

The volatile substance-encapsulated microcapsule dispersion obtained by the production method of the present invention may be the volatile substance-encapsulated microcapsules themselves extracted from the dispersion liquid, which may be directly used in various fields. The dispersion liquid may be applied, sprayed or impregnated on a paper base material or a cloth base material for use. The volatile substance-encapsulating microcapsules obtained by the production method of the present invention are excellent in sustained release of the volatile substance, and therefore have aroma (fragrance, plant essential oil), deodorant, antibacterial (plant essential oil), insect repellent, The medicinal effect such as repellent (agricultural chemicals) can be maintained for a long period of time as compared with the past.

[0051]

As described above, according to the present invention, the oily liquid (A liquid) containing the components a to d is added to the aqueous liquid (liquid B) containing the components e and f to emulsify. Disperse,
By a resinification reaction, a volatile substance-containing microcapsules with a polyurea resin shell formed on the outer periphery of a gel-like polyurethane resin core containing a volatile substance to produce a dispersion liquid are prepared. is there. That is, due to the presence of the polyvalent amine (component e) in the aqueous liquid, the polyfunctional amine and the polyfunctional isocyanate (component b) in the oily liquid (liquid A) react with each other to form the outer shell first. A gel containing a volatile substance (a component) is formed by the reaction of the polyfunctional isocyanate (b component) and the water-insoluble polyol (c component) inside the polyurea resin shell. A special volatile substance-encapsulating microcapsule is obtained in which a core portion made of polyurethane resin is formed, and the core portion made of the volatile substance-containing gel polyurethane resin is covered with a shell portion. Therefore, the obtained volatile substance-encapsulating microcapsules have a core made of a gel polyurethane resin, and the volatile substance contained in the microcapsules has a controlled release amount from the core, and thus has an excellent sustained release property. Prepare Therefore, the volatile substance-containing microcapsules obtained by the present invention are:
Since the excellent sustained-release effect of the encapsulating volatile substance is exhibited, for example, a long-term medicinal effect is required, pesticides, fragrances, vegetable essential oils, etc. It is used in the form of.

In the method for producing such a special volatile substance-encapsulating microcapsule dispersion, when the above oily liquid (Liquid A) does not contain a solvent, volatile substance-encapsulating microcapsules excellent in sustained release are obtained. Will be available.

When silicon dioxide and cyclodextrin are added to the above oily liquid (Liquid A) individually or in combination, the volatilization of a volatile substance further enhances the volatility of the volatile substance. A microcapsule containing a sexual substance can be obtained.

As the volatile substance to be encapsulated, generally, pesticides, fragrances, and plant essential oils can be mentioned. Particularly, it is effective to use allyl isothiocyanate from the viewpoint of sustained release.

Next, examples will be described together with comparative examples.

[0056]

Example 1 100 parts of allyl isothiocyanate (volatile substance), an adduct of hexamethylene diisocyanate and trimethylolpropane [Coronate HL (manufactured by Nippon Polyurethane Co., containing ethyl acetate, isocyanate component concentration 7
5%)] 120 parts (isocyanate component), 1 part of 10% ethyl acetate solution of dibutyltin dilaurate (catalyst),
120 parts of castor oil (water-insoluble polyol) were mixed and dissolved to prepare an oily liquid. Then, add this oily liquid to 25 ° C.
Partially saponified polyvinyl alcohol (Nippon Gosei Kagaku Kogyo KK, Gohsenol KM-11, saponification degree 80%) 35
Parts and 350 parts of an aqueous solution containing 10 parts of ethylenediamine (polyvalent amine), and an emulsion was obtained by stirring at a high speed of 1000 rpm for 5 minutes with an auto homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.). Subsequently, this emulsion was stirred at 25 ° C. for 1.5 hours at a low speed rotation of 200 rpm to complete the reaction to obtain a microcapsule dispersion containing allyl isothiocyanate. When the particles of the microcapsules were taken out by centrifugation and observed with an electron microscope (JSM-T300, manufactured by JEOL Ltd.), particles having a particle diameter of 5 μm were observed. Further, when the microcapsules were broken and observed with an electron microscope, it was confirmed that the core was in a gelled state. This indicates that the gel-like polyurethane resin (core) containing allyl isothiocyanate is a special microcapsule having a core-shell structure encapsulated by a shell made of polyurea resin (see FIG. 1). ).

When the remaining castor oil (water-insoluble polyol) was extracted with tetrahydrofuran using the obtained allyl isothiocyanate-encapsulated microcapsules, castor oil was not detected. This result also shows that castor oil was not present in the core, but completely reacted with the isocyanate component, and the core was a gelled polyurethane resin.

Furthermore, when the above-prepared oily liquid was left as it was at 25 ° C. for 1.5 hours, it lost its fluidity and became in a gelled state.

From these, it is clear that the core of the allyl isothiocyanate-encapsulating microcapsules obtained in Example 1 is gelled.

[0060]

Examples 2 to 10 As a volatile substance (or a volatile substance together with silicon dioxide and cyclodextrin), an isocyanate component, a catalyst and a water-insoluble polyol,
The target volatile substance-containing microcapsule dispersion liquid was prepared in the same manner as in Example 1, using the materials shown in Tables 1 and 2 below in the proportions shown in the same table. Then, the obtained volatile substance-encapsulating microcapsules were taken out by centrifugation, and the particle size was measured by observation with an electron microscope as in Example 1, and the results are shown in Tables 1 and 2 below.

Further, when microcapsules were cut and electron micrographs were taken in the same manner as in Example 1, it was confirmed that the core portion was gelled in all cases. Further, in the same manner as described above, when the water-insoluble polyol was extracted and only the oily liquid was reacted, the same results as in Example 1 were obtained. From these, it is clear that the core portion of the volatile substance-containing microcapsules of Examples 2 to 10 is gelled.

[0062]

[Table 1]

[0063]

[Table 2]

[0064]

Comparative Example 1 When the oily liquid was prepared in Example 1, the catalyst dibutyltin dilaurate was not used. Otherwise, the same operation as in Example 1 was performed. When the obtained emulsion was centrifuged, microcapsules were obtained. When this microcapsule was observed, it was found to be a microcapsule containing castor oil and allyl isothiocyanate (a volatile substance) in the core.

[0065]

Comparative Example 2 When preparing the oily liquid in Example 2, trimethyltin hydroxide as a catalyst was not used. Otherwise, the same operation as in Example 2 was performed. When the obtained emulsion was centrifuged, microcapsules were obtained. When this microcapsule was observed, it was found that the core portion contained castor oil, lemon oil and silicon dioxide (volatile substance).

The dispersion liquid thus obtained in which each microcapsule was dispersed was collected in 5 petri dishes, 1 g each. Then, after leaving them at 25 ° C. for a predetermined number of days, the entire amount of the dispersion liquid in the petri dish is extracted with an organic solvent (tetrahydrofuran) and the content of the volatile substance contained therein is measured by the HPLC method (high performance liquid chromatography). did. Moreover, when the content of the volatile substance encapsulated by the HPLC method was measured in the same manner as above using each dispersion immediately after the preparation, the theoretical content and the actual measurement value were in agreement. The respective contents are shown in Tables 3 and 4 below. Furthermore, the content of the volatile substance was measured for each number of days elapsed by the above method, and the residual rate thereof after standing at room temperature was calculated. The change over time is shown in FIG. In the curve diagram showing the elapsed days-remaining rate in FIG. 4, the curve A is the example 1 and the curve B.
Is Example 2, curve C is Example 3, curve D is Example 4, curve E is Example 5, curve F is Example 6, curve G is Comparative Example 1, and curve H is Comparative Example 2. The residual rates of the volatile substances after 1 week are shown in Tables 5 and 6 below.

[0067]

[Table 3]

[0068]

[Table 4]

[0069]

[Table 5]

[0070]

[Table 6]

Tables 5 and 6 (curve diagram shown in FIG. 4)
Thus, in the conventional volatile substance-containing microcapsules (Comparative Examples 1 and 2), the residual rate of the volatile substance is less than 30% after one week. On the other hand, in the volatile substance-encapsulating microcapsules of Examples, the residual rate of all Examples exceeded 80% even after 1 week, and it is clear that the sustained release property was excellent.

[Brief description of drawings]

FIG. 1 is a cross-sectional view schematically showing an example of a volatile substance-encapsulating microcapsule obtained by the production method of the present invention.

FIG. 2 is a curve diagram showing the relationship between the residual rate of volatile substances and the number of days elapsed.

[Explanation of symbols]

 1 gel-like polyurethane resin 2 shell made of polyurea resin

Claims (6)

[Claims] 1. A process for producing a volatile substance-encapsulated microcapsule dispersion, which comprises adding the following liquid (A) to the following liquid (B), emulsifying and dispersing the mixture to cause a resinification reaction. (A) An oily liquid containing the following components (a) to (d). (A) Volatile substance. (B) Polyfunctional isocyanate. (C) Water-insoluble polyol. (D) Organotin compound. (B) An aqueous liquid containing the following components (e) and (f). (E) A polyvalent amine having at least two amino groups. (F) an emulsifier. 2. The process for producing a volatile substance-encapsulated microcapsule dispersion according to claim 1, wherein the liquid (A) is an oily liquid containing no solvent in the liquid. 3. The volatile substance-encapsulating microsphere according to claim 1, wherein the liquid (A) is an oily liquid containing at least one of silicon dioxide and cyclodextrin in addition to the components (a) to (d). Manufacturing method of capsule dispersion. 4. The volatile substance as the component (a) is a pesticide,
The method for producing a volatile substance-encapsulated microcapsule dispersion according to any one of claims 1 to 3, which is a fragrance or a vegetable essential oil. 5. The method for producing a volatile substance-encapsulating microcapsule dispersion according to any one of claims 1 to 3, wherein the volatile substance (a) is allyl isothiocyanate. 6. A liquid (A) below is added to the liquid (B) below to emulsify and disperse it, and a resinification reaction is carried out to form a microcapsule dispersion liquid containing a volatile substance, and the dispersion liquid is volatile. A method for producing a volatile substance-encapsulating microcapsule, which comprises removing the substance-encapsulating microcapsule. (A) An oily liquid containing the following components (a) to (d). (A) Volatile substance. (B) Polyfunctional isocyanate. (C) Water-insoluble polyol. (D) Organotin compound. (B) An aqueous liquid containing the following components (e) and (f). (E) A polyvalent amine having at least two amino groups. (F) an emulsifier.