JPH1087404A - Acaricide and mite-proof dispersion containing same - Google Patents

Abstract

(57) [Problem] To provide an acaricide capable of exhibiting a medicinal effect of a pyrethroid insecticide contained therein for a long period of time and a mite-proofing agent-containing dispersion containing the same. Kind Code: A1 Abstract: A microcapsule having a core formed of a gel-like polyurethane resin containing a pyrethroid-based insecticide and a shell covering the core formed of a shell made of polyurea resin. It is a tick agent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an acaricide containing microcapsules containing a pyrethroid insecticide and a dispersion containing the mites.

[0002]

2. Description of the Related Art Conventionally, pyrethroid insecticides have been emulsified in water with an activator, processed into paper, clothing, and the like, and have exhibited medicinal properties as an anti-mite agent.

[0003]

However, when used as an anti-mite agent as described above, for example, the washing resistance is poor and the effect cannot be sufficiently maintained for a long period of time. is there.

[0004] It is an object of the present invention to provide an acaricide capable of exhibiting the medicinal effect of a pyrethroid insecticide contained therein for a long period of time and a dispersion containing the acaricide containing the same.

[0005]

In order to achieve the above-mentioned object, the present invention relates to a method for producing a core comprising a gel-like polyurethane resin containing a pyrethroid-based insecticide and a shell covering the core comprising a polyurea resin. A first aspect of the present invention is a mite-controlling agent containing the microcapsules formed by the above, and the second aspect is a micro-capsule containing the pyrethroid-based insecticide dispersed in an aqueous medium. And

The present inventors have conducted a series of studies to obtain microcapsules capable of exhibiting the medicinal properties of pyrethroid insecticides encapsulated for a long period of time. In the process, in the microcapsules having a core-shell structure, as a result of further research centering on the configuration of the core that contains the pyrethroid-based insecticide instead of the shell, the pyrethroid-based insecticide was directly encapsulated as the core. Instead, when a pyrethroid-based insecticide is added to a gel-like polyurethane resin, the pyrethroid-based insecticide is strongly retained in the gel-like polyurethane resin. Reached.

Further, the dispersion liquid in which the microcapsules encapsulating the pyrethroid-based insecticide having the special core structure described above are dispersed in an aqueous medium has various forms such as coating, spraying or impregnating paper or fiber. Can be used.

[0008] Then, the above-mentioned dispersion liquid contains at least one of a water-soluble polyurethane resin and an aqueous emulsion of a synthetic resin as a binder component together with a special pyrethroid-based insecticide-encapsulated microcapsule. When the capsule dispersion is used for processing paper, clothing, and the like, the washing resistance is improved, and the anti-mite performance can be further exhibited over a long period of time.

[0009]

Next, the present invention will be described in detail.

The acaricide of the present invention comprises a microcapsule containing a pyrethroid insecticide as an active ingredient. The microcapsule has a core-shell structure in which the core is covered with a shell. The core is formed of a gel-like polyurethane resin containing a pyrethroid-based insecticide, and the shell is formed of a polyurea resin.

Examples of the pyrethroid-based insecticide contained and retained in the gelled polyurethane resin in the core include, for example, arethrin, resmethrin, permethrin, cyhalothrin, cyfluthrin, fenpropatrin, tralomethrin, cycloprothrin, fenvalerate, fluntrilate. Synthetic pyrethroid insecticides such as catenate, fluvalinate and etofenprox, and natural pyrethroid insecticides such as pyrethrin.

The microcapsule containing the pyrethroid-based insecticide as an active ingredient in the mite-controlling agent of the present invention comprises a pyrethroid-based insecticide contained in the core,
Alternatively, in a hydrophobic medium containing a pyrethroid insecticide,
It is obtained by dissolving a polyfunctional isocyanate, a water-insoluble polyol and a catalyst to form an oil phase, emulsifying and dispersing the oil phase in water (aqueous phase) to which an emulsifier has been added, and then reacting the oil phase at and at the oil droplet interface. .

In the above reaction, 0.5 to 2 at 20 to 40 ° C.
The reaction is completed in about a time, and a dispersion liquid of microcapsules containing a pyrethroid-based insecticide can be produced in a much shorter time and at a lower temperature than before.

First, each component constituting the oil phase will be described.

The oil phase is composed of a pyrethroid insecticide or a hydrophobic medium containing the pyrethroid insecticide, a polyfunctional isocyanate, a water-insoluble polyol, and a catalyst.

The pyrethroid insecticide may be used as it is, or may be contained in a hydrophobic medium as described above. Preferably, a pyrethroid insecticide is used as it is in view of the strength of the microcapsules.

The above-mentioned hydrophobic medium is used as a volatile inhibitor for pyrethroid insecticides, and includes, for example, esters such as benzyl benzoate and dioctyl phthalate, and vegetable oils such as mineral oils and cottonseed oils. .

Examples of the polyfunctional isocyanate used for forming the shell and the gel-like core include phenylene diisocyanate, tolylene diisocyanate, and the like.
Hexamethylene diisocyanate, diphenylmethane diisocyanate, naphthalene diisocyanate, xylylene diisocyanate, polymeric diphenylmethane diisocyanate, isophorone diisocyanate, triphenylmethane triisocyanate, etc. And isocyanate prepolymers which are adducts with polyols such as hexanetriol. These may be used alone or in combination of two or more.

Examples of the 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; Examples include condensates of polyhydric phenols and alkylene oxides, and polyol prepolymers such as polyester polyols and polyether polyols. These may be used alone or in combination of two or more. Among these polyols, it is preferable to use trimethylolpropane from the viewpoint that a pyrethroid-based insecticide-encapsulated microcapsule having excellent residual effect can be obtained.

Among the above polyfunctional isocyanates, it is preferable to use hexamethylene diisocyanate and isophorone diisocyanate from the viewpoint of obtaining a non-yellowing type microcapsule containing a pyrethroid-based insecticide and being economical.

Examples of the water-insoluble polyol used together with the above polyfunctional isocyanate include castor oil, polyoxyalkylene polyol, polyether polyol such as polytetramethylene ether glycol, condensation polyester polyol, lactone polyester. And polyester polyols such as diols and polycarbonate diols. These may be used alone or in combination of two or more. Among these water-insoluble polyols, castor oil is preferably used from the viewpoint of reactivity and residual effect. The mixing amount of the water-insoluble polyol is 10 to 30 parts by weight based on 100 parts by weight of the polyfunctional isocyanate (hereinafter abbreviated as "part").
It is preferably set to 0 parts, particularly preferably 50 to
200 copies. If the amount of the water-insoluble polyol is less than 10 parts or more than 300 parts,
If the amount is outside the above range, it tends to be difficult to obtain a pyrethroid-based insecticide-encapsulating microcapsule having a gel-like core. And, among these water-insoluble polyols, it is necessary to use those 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 such a point, the above-mentioned water-insoluble polyol is used.

Further, as a catalyst used together with the above polyfunctional isocyanate and water-insoluble polyol, an organotin compound is used, for example, tri-n-butyltin acetate, n-butyltin trichloride,
Examples include dimethyltin dichloride, dibutyltin dilaurate, and trimethyltin hydroxide. These catalysts may be used as they are, or may be dissolved in a solvent such as ethyl acetate so as to have a concentration of 0.1 to 20% by weight (hereinafter abbreviated as “%”), and form an isocyanate component in the oil phase. For 100 parts of the polyfunctional isocyanate,
You may add so that it may become 0.01-1 part as solid content. As described above, the amount of the catalyst is set so as to be 0.01 to 1 part as a solid content, based on 100 parts of the polyfunctional isocyanate, either as it is or in a state of being dissolved in a solvent. Preferably,
Particularly preferred is 0.05 to 0.5 part. That is,
If the amount of the catalyst is too small, such as less than 0.01 part, the polyfunctional isocyanate is used in the shell formation reaction before the gelled polyurethane resin in the core is formed, and the shell is first used. On the contrary, if the content exceeds 1 part, the formation of the core part becomes extremely fast, and it tends to be difficult to obtain the intended microcapsules containing the pyrethroid-based insecticide.

By adding the above catalyst, the reaction between the polyfunctional isocyanate in the oil phase and the water-insoluble polyol reacts more quickly than the reaction between the polyfunctional isocyanate and the water in the aqueous phase. Therefore, in forming a core-shell microcapsule, the core is formed of a gel-like polyurethane resin containing a pyrethroid-based insecticide, and the outer periphery (shell) of the core is formed of a polyurea resin. Thus, a pyrethroid-based insecticide-encapsulated microcapsule having a special structure of the present invention can be obtained.

It is preferable that the oil phase composed of the above components does not contain a solvent. That is, if a solvent is contained, the following problem occurs. Due to the odor of the solvent itself, a good product cannot be obtained. In the case of the water-soluble solvent, the water-soluble solvent shifts to the aqueous phase at the time of microcapsule formation, and with this shift, the pyrethroid-based insecticide also shifts from the oil phase to the aqueous phase, so that the intended microcapsules containing the pyrethroid-based insecticide are formed. This is because it becomes difficult to obtain.

Next, an aqueous phase in which the above oil phase is emulsified and dispersed will be described.

As the emulsifier to be added to the above aqueous phase, there can be used water-soluble high-molecular substances each of anionic, cationic, nonionic and amphoteric types, and various surfactants.

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

[0028] Examples of the cationic polymer substance include cationized starch.

Examples of the nonionic polymer include polyvinyl alcohol, methylcellulose, hydroxyethylcellulose, xanthan gum and the like, and examples of the amphoteric polymer include gelatin.

Examples of the above various surfactants include anionic surfactants such as sodium lauryl sulfate, sodium laurylbenzenesulfonate, sodium polyoxyethylene alkylphenyl ether sulfate, polyoxyethylene alkyl ether, and polyoxyethylene alkylphenyl. Examples include nonionic surfactants such as ethers, cationic surfactants such as alkyltrimethylammonium salts, and amphoteric surfactants such as alkyl betaine type and alkyl imidazoline type.

These emulsifiers are generally prepared by adding an aqueous solution to water at a concentration of 1 to 20% to obtain an aqueous phase.

In the present invention, the microcapsule dispersion containing the pyrethroid insecticide is produced, for example, as follows. That is, an oil phase liquid and an aqueous phase are prepared using each of the above components. The oil phase liquid prepared above is added to the aqueous phase, and the mixture is stirred and reacted under predetermined conditions to form a core-shell structure in which the core is covered with a shell, and the core is pyrethroid-based. A pyrethroid-based insecticide-encapsulated microcapsule dispersion is formed in which a special pyrethroid-based insecticide-encapsulated microcapsule formed of a gel-like polyurethane resin containing an insecticide and having the shell portion formed of a polyurea resin is dispersed. Then,
By separating water from the dispersion by a predetermined method, a microcapsule containing a pyrethroid-based insecticide can be obtained.

[0033] In the microcapsule dispersion containing the pyrethroid-based insecticide obtained as described above, the content of the microcapsules containing the pyrethroid-based insecticide in the dispersion is determined by, for example, coating, spraying, or the like on paper or fiber. In consideration of the expected medicinal effect and retention when used by impregnation, it is preferable to set the dispersion in the range of 2 to 70%.

The mixing ratio of the oil phase liquid and the water phase is preferably set so that the weight ratio of the oil phase to the oil phase 1 is 0.5 to 50 with respect to the water phase. Particularly preferably, the ratio of the oil phase to the aqueous phase is 0.8 to 1.5. That is, if the water phase is less than 0.5 with respect to the oil phase 1, it is difficult to make water a continuous phase. Further, when the aqueous phase exceeds 50, there is a tendency that only products having a microcapsule concentration that is too low are obtained.

The stirring conditions are generally 500 to
5000 rpm, particularly preferably 1000-1000 rpm.
3000 rpm. Further, as described above, the reaction conditions are set at 20 to 40 ° C. for a short time of about 0.5 to 2 hours.

Further, it is also possible to obtain only the pyrethroid-based insecticide-encapsulated microcapsules by separating water from the microcapsules containing the pyrethroid-based insecticide. The separation method is not particularly limited, and includes a conventionally known method such as a centrifugal separation method, a pressure filtration method, and a vacuum suction filtration method. Further, the microcapsules encapsulating the pyrethroid insecticide 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 presume the following about the formation mechanism by which a special pyrethroid-based insecticide-encapsulated microcapsule can be obtained from the knowledge obtained through a series of studies on microcapsules. That is, due to the presence of the catalyst, which is one of the components constituting the oil phase, when an oil phase liquid containing the catalyst is added to the aqueous phase and stirred, the polyfunctional isocyanate and the water-insoluble polyol in the oil phase are mixed with each other. Reacts more rapidly than the reaction of a polyfunctional isocyanate with water. For this reason, in the formation of the core-shell structure microcapsules, first, a gel-like polyurethane resin containing a pyrethroid-based insecticide serving as a core is produced by a reaction, and then, on the surface thereof, a polyfunctional isocyanate and water are reacted. Are considered to react to form a polyurea resin to form a shell.

As another method for producing a microcapsule dispersion containing a pyrethroid-based insecticide used in the present invention, the following method can also be mentioned. That is, this is a method in which the oily liquid containing an organotin compound is added to an aqueous liquid containing a polyamine compound having at least two amino groups and an emulsifier to emulsify and disperse. According to this method, since the aqueous liquid contains a polyvalent amine, at the oil droplet interface,
The polyfunctional isocyanate in the oil phase and the polyvalent amine in the aqueous liquid react very quickly, forming a shell made of polyurea resin, and later, by the catalytic action of the organotin compound,
The polyfunctional isocyanate reacts with the water-insoluble polyol to initiate gelation inside the shell, forming a gel-like polyurethane resin core containing the pyrethroid-based insecticide, and the pyrethroid-based insecticide used in the present invention. A dispersion of microcapsules encapsulating a pyrethroid-based insecticide in which a core portion made of a gel-like polyurethane resin is formed in a shell portion is obtained.

FIG. 1 shows a schematic diagram of the thus obtained microcapsules containing pyrethroid insecticide. As shown in the figure, a core-shell structure in which the outer periphery of a gel-like polyurethane resin 1 containing a pyrethroid-based insecticide, which is a core, is encapsulated by a shell 2 made of polyurea resin. The particle size of the microcapsules encapsulating the pyrethroid-based insecticide of the present invention is not particularly limited, but is generally set in the range of 0.5 to 500 μm.

In the present invention, the fact that the core portion of the microcapsule containing the pyrethroid-based insecticide is in a gelled state can be confirmed by observing the cross section of the obtained microcapsule containing the pyrethroid-based insecticide with an electron microscope. Can be. In addition, as a result of performing an extraction operation of the remaining water-insoluble polyol with the solvent using the obtained pyrethroid-based insecticide-encapsulated microcapsules, no extract was obtained, so that the water-insoluble polyol was completely mixed with the polyfunctional isocyanate. It reacts and it is determined that the inside is in a gel state. Further, a pyrethroid insecticide, a polyfunctional isocyanate, a water-insoluble polyol, and a catalyst,
It is inferred from the fact that if the mixture is mixed at 20 to 40 ° C. and left for 0.5 to 2 hours, the fluidity is lost and a gel is formed.

Next, after preparing a liquid in which the above-mentioned microcapsules containing the special pyrethroid-based insecticide are dispersed in an aqueous medium, an aqueous emulsion of a water-soluble polyurethane resin and a synthetic resin as binder components is added to the dispersion. By blending at least one of the above, the effects of further improving the durability of the mite prevention effect and the washing resistance, which are the objects of the present invention, can be obtained.

Among the above binder components, the following water-soluble polyurethane resins include the following (B1) and (B1).
It is preferable to use at least one of 2).

(B1) A heat-reactive water-soluble polyurethane resin obtained by reacting the following (a1) with (b1), the terminal isocyanate group being blocked with a blocking agent. (A1) At least one of polyether polyol and polyester polyol. (B1) a diisocyanate component. (B2) A water-soluble polyurethane resin obtained by cross-linking a terminal isocyanate group of at least one of water and an amine in a reaction product obtained by reacting the following (a2) and (b2). (A2) at least one of a polyether polyol and a polyester polyol. (B2) a diisocyanate component.

First, a heat-reactive water-soluble polyurethane resin (B
1) will be described.

The polyether polyol (a1) includes a block polymer of ethylene oxide and propylene oxide, or a random addition polymer thereof.
Examples include propylene oxide of glycerin, ethylene oxide or a random addition polymer thereof, and an addition polymer of propylene oxide.

Examples of the polyester polyol (a1) include polyester polyols of maleic anhydride and 1,4-butanediol, and polyester polyols of maleic anhydride and 1,6-hexanediol.

As the isocyanate component (b1), an aliphatic diisocyanate is preferably used from the viewpoint of preventing yellowing. Specifically, hexamethylene diisocyanate (HMDI), trimethylxylene diisocyanate (TMXDI), isophorone diisocyanate ( IPDI) and the like.

Further, in (B1), (a)
Examples of a blocking agent for blocking a terminal isocyanate group in a reaction product obtained by reacting 1) and (b1) include anhydrous sodium bisulfite, methyl ethyl ketoxime, and the like.

The heat-reactive water-soluble polyurethane resin (B)
1) is obtained, for example, as follows. That is, the above (a1) and (b1) are reacted at 90 to 100 ° C. (until the terminal isocyanate group becomes about 3 to 4%), and the unreacted terminal isocyanate group is blocked with the blocking agent; After cooling, the activator is added as needed. Next, water is added to this to form an emulsion.

The heat-reactive water-soluble polyurethane resin (B1) thus obtained preferably has a weight average molecular weight of 5,000 to 20,000 from the viewpoint of heat reactivity.

Next, a water-soluble polyurethane resin (B2)
Is described.

Examples of the polyether polyol (a2) include polytetramethylene glycol, a random addition polymer of ethylene oxide and propylene oxide, a random addition polymer thereof, an addition polymer of propylene oxide, and an addition polymerization of ethylene oxide of bisphenol A. Products, addition polymerization products of propylene oxide of bisphenol A, 1,4-butanediol, trimethylolpropane and the like.

Examples of the polyester polyol (a2) include butylene adipate, hexylene carbonate, ethylene terephthalate and the like.

As the isocyanate component (b2), tolylene diisocyanate-80 (TDI-8)
0), HMDI, diphenylmethane diisocyanate (MDI), IPDI and the like.

Further, (a) in (B2) above
Examples of the amine that crosslinks the terminal isocyanate group of the reaction product obtained by reacting 2) and (b2) include ethylenediamine, hydrazine, diethylenetriamine and the like.

The water-soluble polyurethane resin (B2) is
For example, it is obtained as follows. That is, (b2) is reacted with (a2) in a solvent (70
７５75 ° C.) until the desired amount of terminal isocyanate groups. Next, cool, add an activator as needed,
Further, a large amount of water is added to crosslink the terminal isocyanate groups with water. At this time, a diamine can be added for efficient crosslinking.

The water-soluble polyurethane resin (B2) thus obtained preferably has a weight average molecular weight of 30,000 or more from the viewpoint of washing resistance. More preferably, the weight average molecular weight is 100,000 or more.

As the water-soluble polyurethane resin blended in the microcapsule dispersion liquid containing pyrethroid insecticide in the present invention, among the above (B1) and (B2), (B1) is particularly preferable from the viewpoint of washing resistance. Preferably, it is used. Regarding the component (B1), it is preferable to add the organotin compound to the microcapsule dispersion in an amount of 0.5 to 1.0% in order to increase the binder power.

The amount of at least one of (B1) and (B2) to be added is 30 to 30% in terms of solid content with respect to the solid content of the special microcapsule dispersion containing a pyrethroid insecticide.
The ratio is set to 100%, more preferably 50 to 80%.

Among the above binder components, examples of the aqueous emulsion of a synthetic resin include vinyl acetate resin, vinyl acetate-acrylic copolymer resin, vinyl acetate-ethylene copolymer resin, acrylic resin, acrylic-styrene copolymer resin, acetic acid Vinyl-ethylene-vinyl chloride copolymer resin,
Aqueous emulsions such as vinyl acetate-malate copolymer resin, acryl-ethylene-vinyl acetate copolymer resin, and vinylidene chloride resin are exemplified. These synthetic resins are used alone or in combination of two or more. Among them, it is preferable to use an aqueous emulsion of a vinyl acetate-ethylene copolymer resin from the viewpoint of washing resistance.

The above-mentioned aqueous emulsion of the synthetic resin is used at a concentration of 30 to 60%, and the amount of addition is determined in terms of the solid content ratio with respect to the solid content of the liquid in which the microcapsules containing the pyrethroid insecticide are dispersed. It is preferably set to 30 to 100%, more preferably to 50 to 80%.

The mite-controlling agent containing these binder components is added to the above-mentioned microcapsule dispersion containing a special pyrethroid-based insecticide by adding (B1) and (B)
It is obtained by adding at least one of 2) or an aqueous emulsion of the above synthetic resin.

The acaricide of the present invention containing such a microcapsule containing a pyrethroid insecticide as an active ingredient is as follows:
This microcapsule itself may be used as it is, or a dispersion containing an acaricide containing the pyrethroid-based insecticide-containing microcapsule as an active ingredient,
Further, a dispersion containing at least one of the above-mentioned aqueous emulsion of a water-soluble polyurethane resin and a synthetic resin is applied to, for example, a surface of paper, fiber, or the like, or sprayed or dispersed. The present invention can be applied to various articles by using an appropriate method such as immersing and impregnating a liquid.

Next, examples will be described together with comparative examples.

First, prior to the examples, microcapsule dispersions containing a pyrethroid insecticide (pyretrin) were produced.

[0066]

Production Example 1 110 parts of pyrethrin, 120 parts of an adduct of hexamethylene diisocyanate and trimethylolpropane (Nippon Polyurethane Co., Coronate HL) (isocyanate component), 1 part of a 10% ethyl acetate solution of dibutyltin dilaurate (catalyst), An oil phase solution was prepared by mixing and dissolving 120 parts of castor oil (a water-insoluble polyol). Next, this oil phase solution was subjected to partially saponified polyvinyl alcohol (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., Gohsenol KM-
11, 10 parts of an aqueous solution having a saponification degree of 80%) and 350 parts of an aqueous homogenizer (manufactured by Tokushu Kika Kogyo Co., Ltd.).
An emulsion was obtained by stirring at 000 rpm for 5 minutes. Subsequently, this emulsion was added at 25 ° C. for 1.5 hours,
The reaction was completed by stirring at 00 to 500 rpm to obtain a microcapsule dispersion liquid containing pyrethrin (a pyrethroid-based insecticide). The particles of the microcapsules are taken out by centrifugation, and are taken with an electron microscope (manufactured by JEOL Ltd.
(JSM-T300), particles having a particle size 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. From this, it can be seen that the pyrethrin-containing gel-like polyurethane resin (core) is a special microcapsule having a core-shell structure encapsulated by a polyurea resin shell (see FIG. 1).

Using the obtained pyrethrin-encapsulated microcapsules, extraction operation of residual castor oil (water-insoluble polyol) was performed with tetrahydrofuran.
No castor oil was 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.

Further, when the oil phase liquid prepared above was allowed to stand at 25 ° C. for 1.5 hours, it lost its fluidity and became a gelled state.

From these facts, it is clear that the core of the pyrethrin-encapsulated microcapsules obtained in Production Example 1 is gelled.

[0070]

Production Examples 2-6 As pyrethrin, isocyanate component, catalyst and water-insoluble polyol, the materials shown in the following Table 1 were used in the proportions shown in the table, and the target pyrethrin-encapsulated microparticles were produced in the same manner as in Production Example 1. A capsule dispersion was prepared. Then, the obtained microcapsules containing pyrethrin were taken out by centrifugation, and the particle size was measured by observation with an electron microscope in the same manner as in Production Example 1.
Are also shown.

Further, the microcapsules were cut in the same manner as in Production Example 1 and electron micrographs were taken. As a result, it was confirmed that the cores were gelled in each case. Further, in the same manner as described above, the same operation as in Production Example 1 was obtained when the extraction operation of the water-insoluble polyol and the reaction of only the oil phase liquid were performed. From these facts, it is clear that the cores of the pyrethrin-containing microcapsules of Production Examples 2 to 6 are gelled.

[0072]

[Table 1]

[0073]

Comparative Production Example 1 In preparing the oil phase liquid in Production Example 1, castor oil, which is a water-insoluble polyol, and dibutyltin dilaurate, which is a catalyst, were not used. Otherwise, the same operations as in Production Example 1 were performed. When the obtained emulsion was centrifuged, microcapsules were not obtained.
Further, this emulsion was stirred at 25 ° C. for 8 hours to complete the reaction, whereby microcapsules containing pyrethrin were obtained. When the particles of the microcapsules were taken out by centrifugation and observed with an electron microscope in the same manner as in Production Example 1, particles having a particle size of 4 μm were observed. When the microcapsules are broken and observed with an electron microscope, it is found that only the pyrethrin is present in the core, and that the microcapsules simply have a core-shell structure containing pyrethrin.

The above oil phase liquid was allowed to stand at 25 ° C. for 10 hours, but it did not enter a gel state but remained in a liquid state.

From these facts, it is clear that the microcapsules obtained in Comparative Production Example 1 are conventional microcapsules whose core is composed only of pyrethrin.

[0076]

Examples 1 to 6 and Comparative Example 1 [Test for Evaluating Mite Repellent Effect] The microcapsule dispersions containing pyrethrin obtained in Production Examples 1 to 6 and Comparative Production Example 1 were used as test cloth treatment agents, respectively. According to the test method, a mite prevention test and a washing resistance evaluation were performed. The results are shown in Table 2 below.

[Test cloth treatment conditions] The test cloth (100% cotton broad) was immersed in a treatment solution obtained by diluting each of the test cloth treatment chemicals to 1%. The amount was reduced to 0.1%. afterwards,
Preliminary drying (120 ° C. × 2 minutes) was performed. Using this, an anti-mite test shown below was performed, and the washing resistance was evaluated as shown below.

[Mite Prevention Test] Test mite: Dermatophagoides pteronyssima Test item: Test for determining repellent effect (intrusion prevention method) Test method: A plastic petri dish having a diameter of 35 mm × 10 mm in height was placed at the center of a glass petri dish having a diameter of 90 mm × 20 mm in height. And placed on an adhesive sheet.
35m diameter plastic petri dish and 90m diameter
A mite medium recognized to be well propagated between the glass dishes having a size of m was uniformly introduced into about 10,000 individuals as the number of living mites. A processed sample (test cloth treated with a drug) hollowed out so as to be in close contact with the bottom surface of the petri dish was laid on a plastic petri dish having a diameter of 35 mm at the central part, and 0.05 g of powdered feed was placed in the central part as an attractant. The same operation as above was performed on the control (untreated) sample. The Petri dish set in this way is 27cm ×
It was placed in a 13 cm × 9 cm plastic closed container for storing food, kept at 75 ± 5% humidity with saturated saline, and stored in a thermostat at a temperature of 25 ± 1 ° C. Then, 24 hours later, each sample and the mites on the inner surface of the petri dish were washed with water, and the mites in the powdered feed used as the attractant were floated with a saturated saline solution.
The number of live mites was observed. Then, the mite repellent effect was calculated and determined as a tick repellent rate by the following calculation method.

[Calculation method]

(Equation 1)

[Washing resistance test]
Washing was performed for 5 minutes using a home washing machine in water containing 2 g / liter of a detergent (Zabkoso YK, manufactured by Kao Corporation) at a temperature of 40 ° C. and a bath ratio of 1:30 (test cloth: treatment liquid). Then, a 2-minute rinse, a 2-minute dehydration, and a 2-minute rinse were performed, followed by a 2-minute dehydration. With this as one cycle, the above-mentioned mite prevention test was performed at 1, 10, 20, and 30 cycles.

[0081]

[Table 2]

Next, an example in which a water-soluble polyurethane resin is mixed with the pyrethrin-encapsulated microcapsule dispersions obtained in Production Examples 1 to 6 will be described.

[0083]

[Production Example 7] [Production of water-soluble polyurethane resin] Glycerin obtained by addition polymerization of ethylene oxide and propylene oxide, and a mixture of a random addition polymer of propylene oxide and ethylene oxide (weight ratio: 20:80)
Is reacted with HMDI (90-100 ° C.) to form a polyurethane, the terminal isocyanate group is blocked with methyl ethyl ketoxime (MEKO), and further cooled, and water is added to the mixture to form a heat-reactive water-soluble polyurethane resin (weight average molecular weight 1). 15,000) to obtain a dispersion (B1).

[Production of Dispersion Containing Mite Control Agent] Next, the dispersion containing the microcapsules encapsulating pyrethrin obtained in Production Example 1 (solid content of microcapsules, 20%) was prepared.
40 parts of the dispersion (B1) in which the heat-reactive water-soluble polyurethane resin is dispersed is added to 00 parts, and 0.8% of dibutyltin dilaurate is further added. A dispersion was obtained. The solid content concentration of this dispersion was 25%.

[0085]

Production Examples 8 to 12 First, water-soluble polyurethane resins α to ε were produced according to the following production method.

[Water-soluble polyurethane resin α] glycerin obtained by addition polymerization of propylene oxide, and
A mixture of a random addition polymer of propylene oxide and ethylene oxide (20:80 by weight) is reacted with HMDI (90-100 ° C.) to form a polyurethane, and terminal isocyanate groups are blocked with anhydrous sodium bisulfite.
Further cool, add water and add water-soluble polyurethane resin α
Was dispersed to prepare a dispersion α (B1).

[Water-soluble polyurethane resin β] A mixture of a polyester polyol of maleic anhydride and 1,6-hexanediol and polyethylene glycol (5: 1 by weight) is reacted with HMDI (90 to 100 ° C.).
A dispersion β (B1) in which a polyurethane is formed, the terminal isocyanate groups are blocked with anhydrous sodium bisulfite, further cooled, water is added, and a water-soluble polyurethane resin β is dispersed.
Was prepared.

[Water-soluble polyurethane resin γ] glycerin obtained by addition polymerization of propylene oxide, and
A mixture (weight ratio of 50:50) of glycerin obtained by random addition polymerization of ethylene oxide and propylene oxide (weight ratio of ethylene oxide and propylene oxide: 13:87) is reacted with HMDI (90-1).
00 ° C.) into a polyurethane, and the terminal isocyanate group is
Block with anhydrous sodium bisulfite, further cool and add water to disperse γ in which water-soluble polyurethane resin γ is dispersed
(B1) was produced.

[Water-soluble polyurethane resin δ] A mixture of butylene adipate, a random addition polymer of propylene oxide and ethylene oxide, and polycaprolactone (weight ratio of 12: 4: 1) was reacted with HMDI (9).
(0 to 100 ° C.) Polyurethane, water is added, a part of the terminal isocyanate group is reacted with sodium aminoethyl sulfonate, and further cooled to prepare a dispersion δ (B2) in which a water-soluble polyurethane resin δ is dispersed. did.

[Water-soluble polyurethane resin ε] A mixture of polytetramethylene glycol, a random addition polymer of propylene oxide and ethylene oxide, polyethylene glycol, 1,4-butanediol, and trimethylolpropane (weight ratio: 50: 4) : 4: 4: 1.5)
Is reacted with hydrogenated MDI (90 to 100 ° C.) to form a polyurethane, and an activator (ethylene oxide adduct of distyrenated phenol) is added to 5 parts per 100 parts of solids.
Then, a large amount of water was added and emulsified, and the terminal isocyanate group was crosslinked with ethylenediamine to prepare a dispersion ε (B2) in which the water-soluble polyurethane resin ε was dispersed.

A dispersion α in which each of the water-soluble polyurethane resins α to ε was dispersed was added to 100 parts of each of the pyrethrin-encapsulated microcapsule dispersions (microcapsule solid content: 20%) prepared in Production Examples 2 to 6. To ε were added in an amount of 40 parts so that the solid content became 10 parts. The water-soluble polyurethane resins α to ε (dispersion α) used for Production Examples 8 to 12 were used.
~ Ε) is combined with each water-soluble polyurethane resin α ~
It is shown in Table 3 below together with the weight average molecular weight of ε. In addition,
For Production Examples 8 to 10, after adding the above dispersion,
Further, 0.8% of dibutyltin dilaurate was added thereto, and the mixture was stirred to obtain an intended mite-proofing agent-containing dispersion. The solid content concentration of the dispersion was 25%.

[0092]

[Table 3]

Next, an example in which an aqueous emulsion of a synthetic resin is added to the pyrethrin-encapsulated microcapsule dispersion will be described.

[0094]

Production Example 13 A liquid in which the microcapsules encapsulating pyrethrin of Production Example 1 were dispersed (microcapsule solid content 20
%), 100 parts of an aqueous emulsion of a vinyl acetate-ethylene copolymer resin (concentration: 50%, "Movinyl 180E" manufactured by Hoechst Gosei Co., Ltd.) was added in an amount of 20.0 parts so that the solid content became 10 parts. The solid concentration of this dispersion is 25
%Met.

[0095]

Examples 7 to 13 Each of the dispersions obtained in Production Examples 7 to 13 was tested for washing resistance against mites in the same manner as in Examples 1 to 6 according to the method described above. However, the test cloths using Production Examples 7 to 10 were pre-dried (120 ° C. × 2
Minutes), curing was performed (160 ° C. × 2 minutes). The results are shown in Table 4 below.

[0096]

[Table 4]

From the results in Table 4 above, it was found that the aqueous emulsion (vinyl acetate-ethylene copolymer resin) of each of the water-soluble polyurethane resins α to ε and the synthetic resin as the binder component was added to the pyrethrin-encapsulated microcapsule dispersion. Indicates the above Examples 1 to 6 (without a binder component)
It is clear that the washing resistance is more excellent than that of

[0098]

As described above, the present invention relates to a pyrethroid-based composition having a special core structure in which a core made of a gel-like polyurethane resin containing a pyrethroid-based insecticide is covered with a shell made of a polyurea resin. It is an anti-mite agent containing microcapsules containing insecticides. As described above, since the microcapsules have a special core structure, the pyrethroid-based insecticide contained in the gel-like polyurethane resin is only gradually released from the polyurethane resin with time, and exhibits its medicinal effect over a long period of time. It is possible to do. Further, the dispersion liquid in which the above-mentioned pyrethroid-based insecticide-encapsulated microcapsules are dispersed can be used in various forms, such as coating, spraying, or impregnating various materials such as paper and fiber, and the above-described excellent properties are obtained. The residual effect can be exhibited effectively.

Further, at least one of a water-soluble polyurethane resin as a binder component and an aqueous emulsion of a synthetic resin is added to a dispersion in which the microcapsules encapsulating the pyrethroid insecticide of the present invention are dispersed. The washing resistance of various materials to be treated using the dispersion is further improved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view schematically showing an example of a microcapsule encapsulating pyrethrin of the present invention.

[Explanation of symbols]

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

────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁶ Identification code FI A01N 37/38 A01N 37/38 53/02 53/00 502C 53/08 508A 508B 508C 508D 508Z

Claims (5)

[Claims] 1. A method according to claim 1, wherein the core is formed of a gel-like polyurethane resin containing a pyrethroid-based insecticide, and the shell covering the core contains microcapsules formed of a polyurea resin. Tick agent. 2. A dispersion containing a miticide, wherein the microcapsules containing the pyrethroid insecticide according to claim 1 are dispersed in an aqueous medium. 3. The method according to claim 1, wherein the dispersion containing the mite-proofing agent further comprises:
The mite-proofing agent-containing dispersion according to claim 2, which comprises at least one of a water-soluble polyurethane resin and an aqueous emulsion of a synthetic resin. 4. The dispersion according to claim 3, wherein the water-soluble polyurethane resin is at least one of the following (B1) and (B2). (B1) A heat-reactive water-soluble polyurethane resin obtained by reacting the following (a1) with (b1), wherein a terminal isocyanate group is blocked with a blocking agent. (A1) At least one of polyether polyol and polyester polyol. (B1) a diisocyanate component. (B2) A water-soluble polyurethane resin obtained by cross-linking a terminal isocyanate group of at least one of water and an amine in a reaction product obtained by reacting the following (a2) and (b2). (A2) at least one of a polyether polyol and a polyester polyol. (B2) a diisocyanate component. 5. The dispersion according to claim 3, wherein the aqueous emulsion of the synthetic resin is an aqueous emulsion of a vinyl acetate-ethylene copolymer resin.