JPH0987113A - Termite-controlling agent and dispersion containing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a termite-controlling agent free from toxicity, excellent in the termite-killing and controlling performance, not polluting environments, capable of expressing the chemical effect action over a long period, and excellent in the residual activity effect. SOLUTION: This termite-controlling agent contains microcapsules produced by forming the core parts from a get-like polyurethane resin 1 containing allyl isothiocyanate and subsequently covering the formed core parts with the shell parts 2 produced from a polyurethane resin.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a termite control agent containing microcapsules containing allyl isothiocyanate and capable of exerting an excellent residual effect, and a dispersion containing the termite control agent.

[0002]

2. Description of the Related Art Conventionally, organochlorine compounds such as chlordane, lindane and dieldrin have been mainly used as termite controlling agents. While these organochlorine compounds have a long term high effect on termites, they have a problem in terms of environmental pollution, and their use is being banned or gradually regulated. Under these circumstances, organophosphorus pesticides are being used because they are rapidly decomposed and disappear when sprayed into the environment, but they have poor residual effects. There is a proposal that the above-mentioned organophosphorus insecticide is microencapsulated to impart residual effect (JP-A-62-190107).

[0003]

However, this organophosphorus insecticide may have an adverse effect on the human body,
There is also a problem that the residual effect is not sufficient.

The present invention contains a termite control agent which is not toxic to the human body, has excellent insecticidal control performance for termites, has no environmental pollution, and has a residual effect that can exert its medicinal effect for a long period of time. The purpose thereof is to provide a dispersion liquid.

[0005]

In order to achieve the above object, the present invention provides a core made of a gel polyurethane resin containing allyl isothiocyanate, and a shell covering the core is made of polyurea resin. A first term is a termite control agent containing formed microcapsules, and the microcapsules encapsulating the allyl isothiocyanate are
The second gist is a termite-controlling agent-containing dispersion that is dispersed and contained in an aqueous medium.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The present inventors have conducted a series of studies in order to obtain a termite control agent which is excellent in residual efficacy, non-toxic and free from environmental pollution. As a result, the inventors have found that by containing allyl isothiocyanate, which is not toxic to humans and has excellent termite control performance, in a specific microcapsule, the termite insecticidal performance can be exerted over a long period of time, and the present invention has been reached. . That is, a termite control agent containing a microcapsule in which the core portion is formed of a gel polyurethane resin containing allyl isothiocyanate, and the shell portion covering the core portion is formed of polyurea resin and which contains allyl isothiocyanate-containing microcapsules. is there.

The dispersion obtained by dispersing the microcapsules encapsulating allyl isothiocyanate in an aqueous medium has various forms such as coating, spraying or impregnating a paper base material or a cloth base material. Can be used.

Next, the present invention will be described in detail.

The termite control agent of the present invention contains microcapsules containing allyl isothiocyanate as an active ingredient, and the microcapsules have a core-shell structure in which the core is covered with a shell. The core part is formed of a gel polyurethane resin containing allyl isothiocyanate, and the shell part is formed of a polyurea resin.

The allyl isothiocyanate contained in the gelled polyurethane resin at the core is CH _{2 、} CHCH ₂
It is represented by -N = C = S and is not toxic to the human body, but has excellent insecticidal and extermination performance for termites to be used in the present invention.

The microcapsules containing allyl isothiocyanate, which is an active ingredient in the termite control agent of the present invention, are contained in the core of allyl isothiocyanate or a hydrophobic medium containing allyl isothiocyanate. Obtained by dissolving a polyfunctional isocyanate, a water-insoluble polyol and a catalyst to form an oil phase, emulsifying and dispersing this in water (aqueous phase) to which an emulsifier is added, and then reacting at the oil drop interface and inside thereof. .

In the above reaction, 0.5 to 2 at 20 to 40 ° C.
The reaction is completed in about an hour, and microcapsules containing allyl isothiocyanate can be produced in a much shorter time and at lower temperature than in the past.

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

The above oil phase is composed of allyl isothiocyanate or a hydrophobic medium containing allyl isothiocyanate, a polyfunctional isocyanate, a water-insoluble polyol, and a catalyst.

The allyl isothiocyanate may be used as it is, or may be contained in a hydrophobic medium as described above. Preferably, allyl isothiocyanate is used as it is from the viewpoint of residual effect.

The above-mentioned hydrophobic medium is used as a volatile inhibitor for allyl isothiocyanate, 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 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, and polyhydric phenols such as these. 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 microcapsules encapsulating allyl isothiocyanate having excellent residual effects 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 encapsulating allyl isothiocyanate and being economical.

Examples of the water-insoluble polyol used together with the polyfunctional isocyanate include castor oil, polyoxyalkylene polyol, polyether polyol such as polytetramethylene ether glycol, condensation polyester polyol, and 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,
When the amount is outside the above range, it tends to be difficult to obtain a microcapsule encapsulating allyl isothiocyanate in which the target core is a gel. 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 polyfunctional isocyanate and the 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. Is formed. Conversely, if the content exceeds 1 part, the formation of the core becomes extremely fast, and it tends to be difficult to obtain the desired microcapsules containing allyl isothiocyanate.

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 the formation of a core-shell structure microcapsule, the core is formed of a gel-like polyurethane resin containing allyl isothiocyanate, and the outer periphery (shell) of the core is formed of a polyurea resin. Thus, microcapsules encapsulating allyl isothiocyanate having a special structure according to the present invention can be obtained.

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

As the emulsifier added to the above aqueous phase, anionic, cationic, nonionic and amphoteric water-soluble polymer substances and various surfactants can be used.

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.

[0026] Examples of the above-mentioned cationic polymer substance include cationized starch.

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

Further, the above-mentioned 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.

The microcapsule dispersion containing allyl isothiocyanate of the present invention is produced, for example, as follows. That is, an oil phase liquid and an aqueous phase are prepared using each of the above components. Then, 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 isothiocyanic acid. An allyl isothiocyanate-encapsulated microcapsule dispersion is formed in which special allyl isothiocyanate-encapsulated microcapsules formed of a gel-like polyurethane resin containing allyl and having the shell portion formed of a polyurea resin are dispersed. Continuing,
By separating water from the dispersion by a predetermined method, microcapsules containing allyl isothiocyanate can be obtained.

In the allyl isothiocyanate-encapsulated microcapsule dispersion of the present invention obtained as described above, the content of allyl isothiocyanate-encapsulated microcapsules in the dispersion is, for example, by coating, spraying and impregnating wood. Considering the expected drug efficacy and residual efficacy when used,
It is preferably set in the range of 1 to 70% in the dispersion liquid.

The mixing ratio between the oil phase liquid and the aqueous phase is preferably set so that the weight ratio of the oil phase to the oil phase is 0.5 to 50 with respect to the aqueous 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 from 500 to
5000 rpm, particularly preferably 1000-1000 rpm.
3000 rpm. Further, the reaction conditions are set at 20 to 40 ° C. for a short time of about 0.5 to 2 hours as described above.

The method for obtaining water from the allyl isothiocyanate-encapsulated microcapsules by separating water from the allyl isothiocyanate-encapsulated microcapsules is not particularly limited, and a conventionally known method, for example, centrifugation, A pressure filtration method, a reduced pressure suction filtration method and the like can be mentioned. Furthermore, the allyl isothiocyanate-encapsulated 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, regarding the formation mechanism for obtaining a special microcapsule containing allyl isothiocyanate,
The present inventors speculate as follows 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 the oil phase liquid containing this catalyst is added to the aqueous phase and stirred,
The reaction between the polyfunctional isocyanate and the water-insoluble polyol in the oil phase reacts more quickly than the reaction between the polyfunctional isocyanate and water. Therefore, in the formation of the core-shell structure microcapsules, first, a gel-like polyurethane resin containing allyl isothiocyanate serving as a core reacts and then, on the surface thereof, the polyfunctional isocyanate and water are mixed. It is considered that the polyurea resin reacts and reacts to form a shell.

Another method for producing the microcapsules containing allyl isothiocyanate used in the present invention is as follows. 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 polyhydric amine is contained in the aqueous liquid, at the oil droplet interface, the polyfunctional isocyanate in the oil phase and the polyamine in the aqueous liquid react very quickly, and the polyurea resin is used. The shell portion is formed, and by the catalysis of the organotin compound, the polyfunctional isocyanate and the water-insoluble polyol react with each other to start gelation inside the shell portion, resulting in a gel containing allyl isothiocyanate. An allyl isothiocyanate-encapsulated microcapsule used in the present invention having a core portion formed of a polyurethane resin and a core portion formed of a shell made of a gel-like polyurethane resin containing allyl isothiocyanate is obtained.

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

In the microcapsules containing allyl isothiocyanate of the present invention, the fact that the core is in a gelled state can be confirmed by observing the cross section of the obtained microcapsules containing allyl isothiocyanate with an electron microscope. In addition, as a result of performing extraction operation of the remaining water-insoluble polyol with the solvent using the obtained microcapsules containing allyl isothiocyanate, no extract was obtained, so that the water-insoluble polyol completely reacted with the polyfunctional isocyanate. Then, it is determined that the inside is in a gel state. Furthermore, allyl isothiocyanate, a polyfunctional isocyanate, a water-insoluble polyol, and a catalyst are mixed at 20 to 40 ° C. and left for 0.5 to 2 hours to lose fluidity and become a gelled state. Inferred.

The termite control agent of the present invention containing such specific microcapsules as an active ingredient is prepared, for example, by coating or spraying a dispersion liquid containing the microcapsules on the surface of wood or immersing the wood. It can be applied to wood using any suitable method such as impregnation or pressure injection into wood. It is also possible to use it by mixing it with soil.

Next, examples will be described together with comparative examples.

First, prior to the examples, microcapsules containing allyl isothiocyanate were produced.

[Production Example 1] 100 parts of allyl isothiocyanate, an adduct of hexamethylene diisocyanate and trimethylolpropane (Coronate HL, manufactured by Nippon Polyurethane Co.) 12
0 parts (isocyanate component), 1 part of a 10% solution of dibutyltin dilaurate (catalyst) in ethyl acetate, castor oil 12
0 parts (water-insoluble polyol) were mixed and dissolved to prepare an oil phase liquid. Then, a 10% aqueous solution 3 of partially saponified polyvinyl alcohol (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., Gohsenol KM-11, degree of saponification 80%) at 25 ° C.
In addition to 50 parts, the mixture was stirred for 5 minutes at 1000 rpm by an auto homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.) to obtain an emulsion. Subsequently, this emulsion was added at 25 ° C. for 1.
The reaction was completed by stirring at 100 to 500 rpm for 5 hours to obtain microcapsules containing allyl isothiocyanate. The particles of the microcapsules were taken out by centrifugation, and taken with an electron microscope (JSM, 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, a gel-like polyurethane resin containing allyl isothiocyanate (core)
Is a special microcapsule having a core-shell structure encapsulated by a polyurea resin shell (see FIG. 1). An electron micrograph of the microcapsules containing allyl isothiocyanate is shown in FIG.

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 oil phase liquid was allowed to stand as it was at 25 ° C. for 1.5 hours, it lost its fluidity and became in a gel state.

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

[0045]

Production Examples 2 to 6 The materials shown in the following Table 1 were used as the allyl isothiocyanate, the isocyanate component, the catalyst and the water-insoluble polyol in the proportions shown in the following Table. An allyl acid-encapsulated microcapsule dispersion was prepared. Then, the obtained microcapsules containing allyl isothiocyanate 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. The results are shown in Table 1 below.

Further, when microcapsules were cut and electron micrographs were taken in the same manner as in Production Example 1, it was confirmed that the core portion was gelled in all cases. 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 microcapsules containing allyl isothiocyanate of Production Examples 2 to 6 are gelled.

[0047]

[Table 1]

[0048]

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.
The emulsion was stirred at 25 ° C. for 8 hours to complete the reaction, thereby obtaining microcapsules containing allyl isothiocyanate. 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 were broken and observed with an electron microscope, it was found that only allyl isothiocyanate was present in the core, and that the microcapsules had a core-shell structure in which allyl isothiocyanate was simply encapsulated. I understand. An electron micrograph of this microcapsule is shown in FIG.

When the above oil phase liquid was left as it was at 25 ° C. for 10 hours, it did not become a gel state but remained liquid.

From these, it is clear that the microcapsules obtained in Comparative Production Example 1 are conventional microcapsules having a core of allyl isothiocyanate only.

[0051]

Examples 1 to 6 and Comparative Examples 1 and 2 The allyl isothiocyanate-encapsulated microcapsule dispersions obtained in Production Examples 1 to 6 and Comparative Production Example 1 were used as wood treating agents. At this time, the content of each microcapsule in the dispersion was adjusted to 1.0% by weight of the whole.

Then, each of the microcapsule-containing dispersions was placed at a height of 60 on a 15 cm × 15 cm plywood board.
5 ml was sprayed with a spray gun from a distance of cm. After air drying, 20 termites were released on the treated surface at 25 ° C. × 100% relative humidity, and the mortality after 24 hours was determined. Then, after the end of the test, the treated veneer plate was left in a thermostat at 40 ° C., and after 3 months, 6 months, and 9 months, the termite activity against the termites on the treated surface was similarly examined. The test was performed in 5 replicates. The results are shown in Table 2 below.

[0053]

[Table 2]

From the results shown in Table 2 above, the mortality of insects after 24 hours was 100% in all Examples and Comparative Example 1, but the mortality was 3 months, 6 months, and 9 months. Compared to Comparative Example 1 in which the rate was remarkably reduced, the mortality of all the examples was 100% even after 9 months. From this, it can be seen that when the allyl isothiocyanate-encapsulated microcapsule dispersion is used by coating it on a plywood board, excellent residual effect is exhibited over a long period of time.

[0055]

Examples 7 to 12, Comparative Examples 3 to 4 To 400 g of sandy soil, 10 ml of each microcapsule dispersion obtained in Production Examples 1 to 6 and Comparative Production Example 1 was added and mixed well. Next, 5 g of this treated soil was evenly spread in a plastic petri dish having a diameter of 9 cm and covered with filter paper moistened with water, 20 termites were released onto the treated soil, and the mortality rate after 3 days was determined. The remaining treated soil was stored at 40 ° C., and after a predetermined period (3 months, 6 months, 9 months), the residual effect on the termites was examined by the same operation. The test was performed in three round trips. The results are shown in Table 3 below.

[0056]

[Table 3]

From the results shown in Table 3 above, in all Examples and Comparative Example 3, the mortality rate after 3 days was 100%.
Compared to Comparative Example 3 in which the mortality rate was remarkably decreased as the predetermined period of time passed, the mortality rate of all Examples was 1 even after 9 months.
00%. From this, it can be seen that even when the allyl isothiocyanate-encapsulated microcapsule dispersion is added to the soil and treated, it exhibits an excellent residual effect over a long period of time.

[0058]

As described above, the present invention provides allyl isothiocyanate having a special core structure in which the core made of gel polyurethane resin containing allyl isothiocyanate is covered with the shell made of polyurea resin. A termite control agent containing encapsulated microcapsules. By taking such a special core structure, allyl isothiocyanate contained in the gel-like polyurethane resin is gradually released from the polyurethane resin over time, therefore,
The amount of allyl isothiocyanate passing through the shell is suppressed, and as a result, excellent residual efficacy is provided. For this reason,
It is a termite control agent with excellent medicinal effect and residual effect. In particular, this allyl isothiocyanate-encapsulated microcapsule-containing dispersion can be used in various forms such as coating, spraying or impregnating a substrate made of various materials, and the above-mentioned excellent residual effect is effective. Can be demonstrated.

[Brief description of drawings]

FIG. 1 is a cross-sectional view schematically showing one example of a microcapsule containing allyl isothiocyanate of the present invention.

FIG. 2 is an electron micrograph showing a particle structure of allyl isothiocyanate-encapsulating microcapsules produced in Production Example 1.

FIG. 3 is an electron micrograph showing a particle structure of a conventional allyl isothiocyanate-encapsulating microcapsule produced in Comparative Production Example 1.

[Explanation of symbols]

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

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[Procedure amendment]

[Submission date] September 25, 1995

[Procedure Amendment 1]

[Document name to be amended] Drawing

[Correction target item name] Figure 2

[Correction method] Change

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[Fig. 2]

[Procedure amendment 2]

[Document name to be amended] Drawing

[Correction target item name] Figure 3

[Correction method] Change

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[Figure 3]

Claims (2)

[Claims] 1. A termite control characterized in that the core portion is formed of a gel polyurethane resin containing allyl isothiocyanate, and the shell portion covering the core portion contains microcapsules formed of polyurea resin. Agent. 2. A termite-controlling agent-containing dispersion, wherein the microcapsules encapsulating allyl isothiocyanate according to claim 1 are dispersed and contained in an aqueous medium.