insecticide composition

Abstract

To enhance the insecticidal effect of an insecticidal composition by utilizing a cationic surfactant.SOLUTION: An insecticidal composition contains a hydrophobic insecticidal component, a fatty acid, a cationic surfactant, and water. The insecticidal component dissolved in the fatty acid is dispersed in the water.SELECTED DRAWING: None

Description

Technical Field

[0001] The present disclosure relates to an insecticidal composition for killing pests such as flies, cockroaches, ants, etc.

Background Art

[0002] Since many commonly used insecticidal components are hydrophobic, when water is the main solvent, formulation is often carried out by solubilizing or emulsifying the insecticidal component with a surfactant. In the field of insecticides, nonionic surfactants are exclusively used as surfactants for solubilizing or emulsifying insecticidal components, but anionic surfactants may also be used subsidiarily (see, for example, Patent Document 1). Nonionic surfactants and anionic surfactants are generally considered to be excellent in emulsifying and solubilizing power.

[0003] On the other hand, for example, cationic surfactants are generally considered to have an antistatic effect and bactericidal properties, but their application in the field of insecticides has not advanced. In this regard, for example, it is known that an action of avoiding biocide resistance can be obtained by blending a specific organic acid and a cationic surfactant (see, for example, Patent Document 2).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document {[2]}

Summary of the Invention

Problems to be Solved by the Invention

[0005] Incidentally, the biocide efficacy enhancer described in Patent Document 2 is added to an insecticide solution so that it is used at a 1000-fold dilution; therefore, the insecticide must be emulsified or solubilized beforehand. Furthermore, Patent Document 2 is not a technology that particularly focuses on cationic surfactants.

[0006] This disclosure is made in view of the foregoing, and its purpose is to enhance the insecticidal effect in the field of insecticidal compositions by utilizing cationic surfactants. [Means for solving the problem]

[0007] The inventors of this invention have completed the present invention by discovering that a fatty acid and a cationic surfactant can not only disperse a hydrophobic insecticidal component in water, but also enhance the efficacy of the insecticidal component.

[0008] In one aspect of this disclosure, the insecticidal composition comprises a hydrophobic insecticidal component, a fatty acid, a cationic surfactant, and water. The insecticidal component is characterized in that it is dissolved in the fatty acid and dispersed in the water.

[0009] This allows the insecticidal components to be dispersed in water using cationic surfactants, and also enhances the insecticidal effect compared to when they are emulsified and solubilized with nonionic surfactants.

[0010] In other embodiments of this disclosure, the fatty acid may be a saturated fatty acid having 8 to 12 carbon atoms. This allows the insecticidal component to be suitably dispersed in water and its efficacy to be enhanced.

[0011] In other embodiments of this disclosure, the fatty acid may be present in an amount of 1% by weight or more. This embodiment also allows for suitable dispersion of the insecticidal component in water and enhances its efficacy.

[0012] In other embodiments of this disclosure, the fatty acid in which the insecticidal component is dissolved and the cationic surfactant may form a mixed vesicle, and by forming a mixed vesicle in water, the stability over time is improved and the knockdown activity of the insecticidal component is enhanced.

[0013] Cationic surfactants according to other embodiments of this disclosure may include monoalkyl cationic surfactants and dialkyl cationic surfactants. This allows for the suitable formation of vesicles. [Effects of the Invention]

[0014] As explained above, cationic surfactants can be used to disperse insecticidal components in water, thereby enhancing the insecticidal effect. [Modes for carrying out the invention]

[0015] The embodiments of the present invention will be described in detail below. The following description of preferred embodiments is essentially illustrative and is not intended to limit the present invention, its applications, or its uses.

[0016] The insecticidal composition according to this embodiment contains a hydrophobic insecticidal component, a fatty acid, a cationic surfactant, and water, wherein the insecticidal component dissolved in the fatty acid is dispersed in the water.

[0017] <Hydrophobic insecticide ingredients> The hydrophobic insecticidal components are not particularly limited. Examples of usable insecticidal components include pyrethroid insecticides. Examples of pyrethroid insecticides include transfluthrin, pyrethrin, allethrin, phthalthrin, tetramethrin, prallethrin, phenothrin, tralomethrin, cyfluthrin, resmethrin, permethrin, empenthrin, cyphenothrin, imiprothrin, fenpropathrin, fenvalerate, etofenprox, and silafluofen. Transfluthrin, phthalthrin, prallethrin, and imiprothrin, which have a rapid knockdown effect, are particularly preferred. One or more of these can be used in combination. The insecticidal components can also be called pest control components. The concentration of the insecticidal components can be, for example, 0.01% by mass or more and 0.20% by mass or less.

[0018] <Fatty acids> As fatty acids, saturated fatty acids with 8 to 12 carbon atoms can be used. Examples of such fatty acids include pelargonic acid, caprylic acid, and lauric acid, and any one of these or any combination of several can be used.

[0019] <Cationic surfactants> As cationic surfactants, one or both of monoalkyl cationic surfactants and dialkyl cationic surfactants can be used. Examples of monoalkyl cationic surfactants include lauryltrimethylammonium chloride, myristyltrimethylammonium chloride, cetyltrimethylammonium chloride, stearyltrimethylammonium chloride, behenyltrimethylammonium chloride, alkyl(C12-C16)trimethylammonium chloride, and alkyl(C16-C18)trimethylammonium chloride.

[0020] Examples of the dialkyl cationic surfactant include dioctyldimethylammonium chloride, didecyldimethylammonium chloride, dilauryl dimethyl ammonium chloride, dialkyl (C12-C18) dimethyl ammonium chloride, didecyldimethylammonium chloride, dialkyldimethylammonium chloride, dialkyl (C16-18) dimethyl ammonium chloride, and the like.

[0021] The cationic surfactant may be only a monoalkyl cationic surfactant or only a dialkyl cationic surfactant. Further, the cationic surfactant may contain a monoalkyl cationic surfactant and a dialkyl cationic surfactant. In this case, it may contain one kind of monoalkyl cationic surfactant and two or more kinds of dialkyl cationic surfactants, or two or more kinds of monoalkyl cationic surfactants and one kind of dialkyl cationic surfactant.

[0022] <Water> Water is a component that serves as a solvent for the fatty acid. The water that can be used is not particularly limited, and examples thereof include purified water, ion-exchanged water, tap water, hot spring water, deep ocean water, plant distilled water, and the like.

[0023] <Concentration of fatty acid> In addition, the upper limit of the concentration of the fatty acid is set to 8% by mass or less. The upper limit of the concentration of the fatty acid can also be set to 7% by mass or less. When the concentration of the fatty acid exceeds the above range, it becomes difficult to form the mixed vesicles described later, and the viscosity of the insecticidal composition becomes high, making it unsuitable for spraying or spreading. The lower limit of the concentration of the fatty acid can be set, for example, to 1% by mass or more. The lower limit of the concentration of the fatty acid may be set, for example, to 2% by mass or more.

[0024] <Concentration ratio of fatty acid to cationic surfactant> The concentration ratio of cationic surfactant to fatty acid (concentration of cationic surfactant / concentration of fatty acid) is set to 0.8 or higher. The concentration ratio can also be set to 0.9 or higher. The upper limit of the concentration ratio can be set to, for example, 10.0 or less, or to 8.0 or less.

[0025] <Concentration of cationic surfactant> The concentration of cationic surfactant is set to 1% by mass or higher. The concentration of cationic surfactant can also be set to 1.5% by mass or higher. The upper limit of the cationic surfactant concentration is set to 20% by mass or lower. The upper limit of the cationic surfactant concentration can also be set to 19% by mass or lower.

[0026] <Other ingredients> The insecticidal composition may also contain other components, such as alcohols and preservatives. The alcohol is preferably a monohydric or polyhydric alcohol with 2 to 6 carbon atoms and 1 to 6 hydroxyl groups. Examples of such alcohols include ethyl alcohol, propyl alcohol, isopropyl alcohol, 1,3-butylene glycol, propylene glycol, dipropylene glycol, glycerin, and sorbitol. Using these specific alcohols ensures more reliable formation of mixed vesicles in water.

[0027] Examples of preservatives include isothiazolinone derivatives, but these are components that do not affect the insecticidal efficacy.

[0028] <Formation of mixed vesicles> The insecticidal composition according to this embodiment, by blending fatty acids and cationic surfactants as described above, allows the fatty acids containing the dissolved insecticidal component and the cationic surfactant to form mixed vesicles in water. In this case, the fatty acids containing the dissolved insecticidal component interact with the cationic surfactant in water to form mixed vesicles. These mixed vesicles are self-assemblies in which amphiphilic molecules, which are both hydrophobic and hydrophilic in water, are arranged without gaps to form a spherical shell or sac-like structure. Because the layers of the self-assemblies consist of multiple phases, the fatty acids are uniformly contained, allowing for long-term stabilization of the fatty acids in water.

[0029] However, from the perspective of uniformly dispersing the insecticidal components in water, the formation of mixed vesicles is not essential. In other words, even if mixed vesicles are not formed, the insecticidal components can be dispersed in water by fatty acids and cationic surfactants.

[0030] <Method for producing insecticide compositions> An example of a method for producing an insecticidal composition is described below. First, a hydrophobic insecticidal component is dissolved in a fatty acid, and purified water heated to, for example, 70°C is prepared. The insecticidal component dissolved in the fatty acid, a cationic surfactant, and alcohol are dissolved in this purified water. After cooling to room temperature, a preservative is added.

[0031] <How to use the insecticide composition> The insecticide composition according to this embodiment can be used by spraying or distributing it to pests. For example, the insecticide composition can be placed in a spray container (not shown), such as a spray bottle or aerosol container, and then the spray nozzle of the spray container can be pointed towards the pest, and the spray button or trigger can be operated to cause the insecticide composition to be ejected from the nozzle and adhere to the pest. Alternatively, for example, the insecticide composition can be placed in a shower container, and the shower container can be tilted to spray it onto the pests.

[0032] <Examples and Comparative Examples> Examples 1-7 are shown in Table 1, and Comparative Examples 1-4 are shown in Table 2. Comparative Example 5 is also shown in Table 1. After preparing the samples for the examples and comparative examples, they were placed in 100 ml glass bottles and their appearance was visually evaluated at room temperature (RT). In addition, each sample was placed in a 100 ml glass bottle and placed in a box with orthogonal polarizing plates (crossed nicols) at room temperature (RT). Light was then shone onto the sample bottles from outside the polarizing plate box, and the presence or absence of mixed vesicle formation was evaluated by visually observing the pattern of light passing through the sample bottles via the polarizing plates. The meaning of the "Appearance" column in the tables is as follows.

[0033] Vesicles: Mixed vesicles are formed, resulting in a uniform state. Opacity: No mixed vesicles are formed, but a uniform turbidity (emulsification) state is observed. Not dispersed: No mixed vesicles are formed; the mixture remains separated into two layers. Solubilization: No mixed vesicles are formed; the solution is uniform, transparent, or translucent.

[0034] In Examples 1-3, 6, and 7, the insecticidal component was dispersed in water, and vesicles were formed. In Examples 4 and 5, vesicles were not formed in the water, but the component was uniformly dispersed. Comparative Examples 1 and 3 are conventional techniques in which the insecticidal component is solubilized using a nonionic surfactant. Comparative Examples 2 and 4 contain pelargonic acid in addition to the nonionic surfactant. In Comparative Examples 1-4, the component was solubilized, but vesicles were not formed in the water. In Comparative Example 5, the insecticidal component was not dispersed in the water.

[0035] [Table 1]

[0036] [Table 2]

[0037] As described above, a cationic surfactant and a fatty acid can uniformly disperse hydrophobic insecticidal components in water. As shown in Comparative Example 5, a cationic surfactant alone (without fatty acids) cannot disperse insecticidal components in water. Also, although not shown in the table, a fatty acid alone (without cationic surfactant) cannot disperse insecticidal components in water. This is because higher fatty acids such as caprylic acid, pelargonic acid, and lauric acid are themselves hydrophobic and do not mix with water.

[0038] In other words, it is clear that using either a cationic surfactant or a fatty acid alone is insufficient to disperse insecticidal components in water, while a combination of a cationic surfactant and a fatty acid allows for the uniform dispersion of hydrophobic insecticidal components in water.

[0039] <Knockdown test> Next, we will explain the knockdown test. Knockdown refers to a state in which an insect is lying on its back and unable to move normally. First, the test method is as follows: prepare glass rings with a diameter of 8 cm. The test insects are houseflies, German cockroaches, and Argentine ants. Place each test insect in a glass ring and seal it with a mesh net, and prepare 12 such sets (Examples 1-7, Comparative Examples 1-5). The compositions of Examples 1-7 and Comparative Examples 1-5 were sprayed once into each glass ring from a distance of 20 cm from each mesh net using a hand sprayer. Time measurement started after spraying, and the time required for 50% of the test insects to be knocked down (KT50: 50% knockdown time) was calculated. A smaller value indicates faster knockdown. The average time obtained from three repeated tests is shown in Table 3. Note that the KT50 unit for houseflies and Argentine ants is "seconds (sec)", while the KT50 unit for German cockroaches is "minutes (min)".

[0040] [Table 3]

[0041] As shown in Table 3, in all of Examples 1 to 7, the knockdown effect against houseflies, German cockroaches, and Argentine ants appeared early. In contrast, in Comparative Examples 1 and 3, which did not contain fatty acids, German cockroaches were not knocked down for more than 30 minutes, and the knockdown time for houseflies was extremely long, exceeding 55 seconds. The knockdown time for Argentine ants in Comparative Example 3 was also longer than in Examples 1 to 5, exceeding 36 seconds. Comparative Example 5 could not be tested because the insecticidal component did not disperse in water.

[0042] Thus, it is evident that a sprayable, water-based insecticidal composition with a knockdown effect can be obtained by uniformly dispersing a hydrophobic insecticidal component in water using fatty acids and cationic surfactants. This knockdown effect is comparable to that of conventional techniques (Comparative Examples 1 and 3) that disperse the component in water using nonionic surfactants. Furthermore, when mixed vesicles are formed in water (Examples 1, 2, 3, 6, and 7), an enhanced knockdown effect (reduced knockdown time) is obtained compared to when vesicles are not formed (Examples 4 and 5).

[0043] <Lethal Test> Next, we will describe the lethal test. A test system similar to the knockdown test was prepared. The compositions of Examples 1-7 and Comparative Examples 1-5 were sprayed once into each glass ring from a distance of 20 cm from each mesh net using a hand sprayer. Table 5 shows the lethality of the test insects 24 hours after spraying.

[0044] [Table 4]

[0045] As shown in Table 4, all of Examples 1 to 7 showed high lethality against houseflies and Argentine ants. Furthermore, higher lethality was achieved against German cockroaches compared to the comparative examples. In particular, Examples 1 to 3, 6, and 7, where vesicles were formed, showed high lethality against German cockroaches. On the other hand, Comparative Example 1 showed lower lethality against houseflies and German cockroaches compared to the examples, and Comparative Examples 2 and 3 showed extremely low lethality against German cockroaches at 3%. Comparative Example 3 showed 0% lethality against houseflies, and Comparative Example 4 also showed low lethality against houseflies and German cockroaches. Comparative Example 5 could not be tested because the insecticidal component did not disperse in water.

[0046] Thus, by uniformly dispersing hydrophobic insecticidal components in water using fatty acids and cationic surfactants, a lethal effect comparable to that of conventional techniques (Comparative Examples 1-4) that disperse the components in water using nonionic surfactants can be obtained. Furthermore, when mixed vesicles are formed in water (Examples 1, 2, 3, 6, 7), the lethal effect against German cockroaches is particularly enhanced.

[0047] <Stability over time> Next, we will explain the results of the stability tests. In Tables 5 and 6, "RT (Room Temperature)" refers to the case where the product was stored at room temperature for one month immediately after manufacture, "5°C" refers to the case where the product was stored at 5°C for one month immediately after manufacture, and "50°C" refers to the case where the product was stored at 50°C for one month immediately after manufacture.

[0048] ○: No separation (uniform single phase).

[0049] ×: Completely separated into two phases.

[0050] [Table 5]

[0051] Table 5 shows the formulation examples for Examples 8-18. In Examples 8-18, vesicles are formed in water.

[0052] [Table 6]

[0053] Table 6 shows formulation examples for Comparative Examples 6-10. Comparative Examples 6, 7, and 9 are cloudy, and no vesicles are formed in the water. Comparative Examples 8 and 10 are transparent gel-like, and no vesicles are formed in the water. Comparative Examples 6-10 are designated as "comparative examples" in order to be compared with Examples 8-18 in terms of the presence or absence of vesicle formation, but as mentioned above, even if vesicles are not formed in the water, the insecticidal component can be uniformly dispersed in the water.

[0054] As shown in Table 5, the formation of vesicles prevented separation even after one month, maintaining the translucent state immediately after manufacturing. Although the results for Examples 1-3, 6, and 7 are not shown in the table, they also maintained the translucent state immediately after manufacturing without separation even after one month.

[0055] On the other hand, in Comparative Examples 6-10 shown in Table 6, the products were either cloudy or had a clear gel-like state immediately after manufacturing. Although the insecticidal components were initially dispersed in water, their stability was poor, and separation occurred, especially after one month of storage at 50°C. Furthermore, Comparative Examples 8 and 10 gelled immediately after manufacturing, making them unsuitable for use in spraying or other applications. In addition, Comparative Example 5 was separated immediately after manufacturing, making it unsuitable for use as an insecticide.

[0056] As described above, the formation of mixed vesicles in water by the fatty acid containing the insecticidal component and the cationic surfactant allows for the stable maintenance of a dispersed state suitable for use (spraying or dispensing) of the insecticidal composition over a long period of time.

[0057] The embodiments described above are merely illustrative in all respects and should not be interpreted restrictively. Furthermore, any modifications or changes that fall within the equivalent scope of the claims are all within the scope of the present invention. [Industrial applicability]

[0058] As described above, the present invention can be used to kill various pests.

Claims

1. Hydrophobic insecticide components, Fatty acids and, Cationic surfactants and Water and, Includes, The aforementioned fatty acid is a saturated fatty acid having 8 to 12 carbon atoms. The cationic surfactant includes a monoalkyl cationic surfactant or a dialkyl cationic surfactant. The fatty acid in which the insecticidal component is dissolved and the cationic surfactant form a mixed vesicle, and the insecticidal component dissolved in the fatty acid is dispersed in water. The insecticidal composition is characterized in that the mixed vesicle is a self-assembly in which amphiphilic molecules, which are both hydrophobic and hydrophilic, are arranged without gaps to form a spherical shell or sac-like structure in the water.

2. The insecticidal composition according to claim 1, An insecticidal composition characterized by containing 1% by weight or more of the aforementioned fatty acid.

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