Insecticide composition

Abstract

The objective is to provide an insecticide composition that is aqueous in nature, using water as a solvent, yet exhibits excellent stability by suppressing separation and precipitation during storage. [Solution] An insecticide composition containing (A) an insecticidal component, (B) a surfactant, (C) an additive, and (D) water, wherein the (C) additive is one or more selected from the group consisting of organic acid salts, alkaline agents, inorganic salts, and chelating agents. It is preferable that the (A) insecticidal component contains at least a pyrethroid compound.

Description

【Technical Field】 【0001】 The present invention relates to an insecticide composition containing an insecticidal component, and more particularly to an aqueous insecticide composition using water as a solvent. 【Background Art】 【0002】 When formulating an insecticidal component, which is an organic compound, as an insecticide composition, an aqueous formulation using water as a solvent is safer than a formulation solubilizing the insecticidal component in an organic solvent, and has the advantage that the insecticidal component is easily diffused. 【0003】 Therefore, when manufacturing an insecticide composition, a method of dispersing and solubilizing an insecticidal component in water using a surfactant is generally adopted. However, in an aqueous formulation, separation, precipitation, etc. may occur depending on the storage conditions after manufacturing the insecticide composition. If separation, precipitation, etc. occur in the insecticide composition, there is a risk that the intended effect cannot be exhibited. To solve such problems, as disclosed in Patent Document 1, a method of improving the stability of an insecticide composition by blending an organic solvent as a stabilizer has been carried out. 【Prior Art Documents】 【Patent Documents】 【0004】 【Patent Document 1】 Japanese Patent Application Laid-Open No. 2013-95744 【Summary of the Invention】 【Problems to be Solved by the Invention】 【0005】 However, it is known that an organic solvent causes deterioration, alteration, and even cracking when applied to materials such as plastics. Therefore, when blending an organic solvent as a stabilizer, there is a problem that it cannot be used depending on the material of the object to be treated with the chemical. In addition, depending on the type and amount of the organic solvent, the flash point of the insecticide composition may decrease, increasing the risk as a product. 【0006】 Therefore, in view of the above problems, the present invention aims to provide an insecticide composition that is an aqueous formulation using water as a solvent, yet suppresses separation and precipitation during storage and exhibits excellent stability. [Means for solving the problem] 【0007】 To achieve the above objective, in one aspect of the present invention, an insecticide composition is provided which contains (A) an insecticidal component, (B) a surfactant, (C) an additive, and (D) water, wherein the (C) additive is one or more selected from the group consisting of organic acid salts, alkaline agents, inorganic salts, and chelating agents. 【0008】 The insecticidal component (A) may be a pyrethroid compound. 【0009】 The amount of surfactant (B) may be such that, after standing the composition containing (A), (B), and (D) but without (C) at 20°C for 24 hours, neither separation nor precipitation occurs. [Effects of the Invention] 【0010】 According to one aspect of the present invention, although it is an aqueous formulation using water as a solvent, by incorporating a predetermined additive, it is possible to obtain an insecticide composition that is highly stable and can suppress the occurrence of separation and precipitation during storage without incorporating an organic solvent as a stabilizer. [Modes for carrying out the invention] 【0011】 Embodiments of the present invention will be described below. The embodiments described below are merely examples of the present invention and do not limit the technical scope of the present invention. The insecticide composition of this embodiment is an insecticide composition containing (A) an insecticidal component, (B) a surfactant, (C) an additive, and (D) water, wherein the (C) additive is one or more selected from the group consisting of organic acid salts, alkaline agents, inorganic salts, and chelating agents. 【0012】 In this embodiment, (A) the insecticidal component is an organic compound having insecticidal activity. Examples include allethrin, prallethrin, phthalthrin, transfluthrin, metofluthrin, profluthrin, teralethrin, flamethrin, monfluorothrin, dimefluthrin, mepafluthrin, heptafluthrin, phenothrin, cyphenothrin, permethrin, cypermethrin, cyfluthrin, bifenthrin, fenpropatrin, deltamethrin, tralomethrin, imiprothrin, resmethrin, natural pyrethrins, pyrethroid compounds such as silafluofen (which is also an organosilicon insecticide), etofenprox, organophosphates such as fenitrothion, diazinon, and propaphos, carbamates such as propoxur and methoxydiazone, cartap, and buprofezin. 【0013】 These insecticidal components can be used individually or in combination of two or more. Among the above insecticidal components, pyrethroid compounds are preferred because they have low toxicity to warm-blooded animals and high safety for humans. More preferably, pyrethroid compounds having an m-phenoxybenzyl skeleton, such as etofenprox, silafluofen, cyfluthrin, phenothrin, cyphenothrin, permethrin, cypermethrin, fenpropathrin, deltamethrin, and tralomethrin, or pyrethroid compounds having a 2,3,5,6-tetrafluorobenzyl skeleton, such as transfluthrin, metofluthrin, profluthrin, monfluorothrin, dimefluthrin, mepafluthrin, and heptafluthrin, are preferred. Even more preferably, etofenprox and silafluofen are preferred because they have low toxicity to fish. (A) The amount of insecticidal component to be added is preferably 0.1% to 15% by mass, more preferably 0.1% to 2% by mass, and even more preferably 0.1% to 1% by mass, based on the total amount of the insecticide composition, taking into consideration the balance between the efficacy and the solubilization of the insecticidal component. 【0014】 In this embodiment, any of the following surfactants can be used as (B): anionic surfactants, cationic surfactants, and nonionic surfactants. These surfactants can be used individually or in combination of two or more. More specifically, anionic surfactants include carboxylates, sulfonates, sulfate esters, and phosphate esters. Cationic surfactants include aliphatic amine salts and their quaternary ammonium salts, aromatic quaternary ammonium salts, and heterocyclic quaternary ammonium salts. 【0015】 Examples of nonionic surfactants include ether-type nonionic surfactants such as polyoxyethylene alkyl ethers, polyoxyethylene alkylphenyl ethers, polyoxyethylene polyoxypropylene alkyl ethers, and polyoxyethylene alkylamino ethers; ether ester-type nonionic surfactants such as polyoxyethylene glycerin fatty acid esters, polyoxyethylene hydrogenated castor oil, and polyoxyethylene sorbitan fatty acid esters; and ester-type nonionic surfactants such as polyethylene glycol fatty acid esters, fatty acid monoglycerides, polyglycerin fatty acid esters, and sorbitan fatty acid esters. 【0016】 (A) When pyrethroid compounds are used as insecticidal components, it is desirable that the nonionic surfactant has an HLB value of 9.0 or higher. This improves the storage stability of the insecticide composition. In this specification, the HLB value refers to the hydrophilic-lipophilic balance value and takes a value from 0 to 20. The closer to 0, the higher the lipophilicity, and the closer to 20, the higher the hydrophilicity. 【0017】 In this embodiment, one or more additives selected from organic acid salts, alkaline agents, inorganic salts, and chelating agents can be used as (C) additives. Examples of organic acid salts include citrate, lactate, fumarate, gluconate, acetate, succinate, etc. Examples of alkaline agents include bicarbonate, triethanolamine, and metal hydroxides. Examples of inorganic salts include metal sulfate salts and metal chlorides. In all cases of organic acid salts, alkaline agents, and inorganic salts, sodium salts or potassium salts are preferred as the type of salt. In this specification, a chelating agent means a compound that can coordinate with metal ions to form a chelate (complex), and examples include metal salts of ethylenediaminetetraacetic acid (EDTA) and metal salts of ethylenediamine-N,N'-disuccinic acid (EDDS). 【0018】 (B) There are no particular restrictions on the amount of surfactant added; it can be any amount that prevents separation and precipitation after the composition containing (A) to (D) has been left to stand at room temperature (20°C) for 24 hours. However, it is preferable that the amount of surfactant added (B) is such that the composition containing (A), (B), and (D) but without (C) does not separate or precipitate after being left to stand at 20°C for 24 hours. This makes it possible to ensure the stability of the insecticide composition at room temperature by adding the surfactant. Adding the additive (C) further improves the stability of the insecticide composition against temperature changes. To elaborate on the stability of the insecticide composition, when the insecticide composition is stored at low temperatures in particular, it is prone to separation and precipitation. Adding the additive makes it possible to suppress the occurrence of separation, precipitation, etc. of the insecticide composition. Specifically, it is preferable that the (B) surfactant / (A) insecticide component (mass ratio) is 5 or more, and more preferably 5 to 100. 【0019】 The amount of surfactant (B) added to the total insecticide composition is preferable as it is less expensive and reduces the environmental burden. From this viewpoint, the amount of surfactant (B) added can be such that when a composition containing (A), (B), and (D) but without (C) is left to stand at 20°C for 24 hours, neither separation nor precipitation occurs, and when a composition without (C) is left to stand at 5°C for 24 hours, separation or precipitation occurs. Specifically, a ratio of surfactant (B) to insecticide component (A) (mass ratio) of 5 to 40 is preferred. 【0020】 This allows for a reduction in the amount of surfactant (B) added. Furthermore, the amount of additive (C) can be set so that the insecticide composition does not separate or precipitate after being left to stand at 5°C for 24 hours. Specifically, the amount of additive (C) is preferably 0.1% to 60% by mass of the total insecticide composition, more preferably 0.1% to 30% by mass, and even more preferably 0.1% to 10% by mass. The amount of surfactant (B) may also be set so that the composition without (C) does not separate or precipitate after being left to stand at 5°C for 24 hours. Even if the amount of surfactant is set so that the insecticide composition does not separate or precipitate after being left to stand at 5°C for 24 hours, the low-temperature stability of the insecticide composition can be further improved by adding the additive. 【0021】 As described above, in a method for preparing an insecticide composition containing (A) an insecticidal component, (B) a surfactant, (C) an additive, and (D) water, the amount of surfactant (B) can be adjusted such that when a composition containing (A), (B), and (D) but without (C) is left to stand at 20°C for a certain period of time, neither separation nor precipitation occurs, and when a composition without (C) is left to stand at a predetermined temperature lower than 20°C for a certain period of time, separation or precipitation occurs. The amount of additive (C) can also be adjusted such that when an insecticide composition containing (A) to (D) is left to stand at the predetermined temperature for a certain period of time, neither separation nor precipitation occurs. 【0022】 The pesticidal composition prepared in this way has the effect of being excellent in low-temperature stability (stability at a predetermined temperature lower than 20°C) while suppressing the blending amount of the (B) surfactant. Here, the predetermined temperature lower than 20°C can be appropriately set according to the assumed storage environment of the pesticidal composition. Specifically, it can be set, for example, at 0°C to 10°C so that a certain temperature difference from 20°C occurs. 【0023】 Also, the fixed time is preferably the time when the pesticidal composition is left standing to determine its stability, and for example, it can be set at 12 hours to 24 hours. Empirically, the appearance of the pesticidal composition when it is left standing for 24 hours is at the same level as the appearance when the standing time is extended later, so it can be about 24 hours. 【0024】 As described above, the pesticidal composition of the present invention only needs to not cause either separation or precipitation at 20°C (room temperature), but it is preferably transparent, which can improve the stability against external changes such as temperature changes after production. From this perspective, the pesticidal composition of the present invention is more preferably transparent even at a temperature lower than 20°C (for example, 5°C). Here, "transparent" means that the absorbance at a wavelength of 500 nm is less than 1.0. 【0025】 The pesticidal composition according to the present invention is an aqueous formulation using water as a solvent, but since a predetermined additive is blended, it is possible to suppress the occurrence of separation, precipitation, etc. during storage of the pesticidal composition without blending an organic solvent as a stabilizer. However, it is also possible to blend an organic solvent in the pesticidal composition as long as the effects of the present invention are not impaired. In other words, it is sufficient that it is substantially free of an organic solvent. 【0026】 In other words, even when the insecticide composition is applied to plastic, it is acceptable for it to contain an amount of organic solvent that does not cause deterioration, alteration, cracking, etc., of the plastic. Specifically, the amount of organic solvent in the total insecticide composition should be 20% by mass or less, and more preferably 10% by mass or less. Furthermore, the aqueous insecticide composition of the present invention may also contain fragrances, deodorizers, disinfectants, dyes, etc., as needed, to the extent that they do not impair the effects of the present invention. [Examples] 【0027】 The present invention will be described in detail below with reference to examples. However, the present invention is not limited to these examples. 【0028】 [Evaluation of nonionic surfactants] In preparing the insecticide composition, we first tested the relationship between the HLB value and the stability of the insecticide composition when a nonionic surfactant was used as the (B) surfactant (see Tests 1-5 in Table 1). For (A) the insecticidal component, we used etofenprox, a pyrethroid compound, and for (B) the surfactant, we used five different nonionic surfactants with varying average moles of ethylene oxide (EO) added, all derived from polyoxyethylene hydrogenated castor oil. 【0029】 Next, using (B) hydrogenated castor oil with an HLB value of 13.1 as the surfactant, we tested the relationship between the mass ratio of surfactant content / insecticide content and the stability of the insecticide composition (Tests 6-11 in Table 1). In this test, the insecticide composition was prepared by combining (A) the insecticide component, (B) the surfactant, and water without (C) the additive, and the appearance of the insecticide composition was visually evaluated after standing at a specified temperature for 24 hours. The evaluation criteria are as follows. ◎: The insecticide composition is colorless and transparent (absorbance at a wavelength of 500 nm is less than 1.0). ○: The insecticide composition is semi-transparent or cloudy, but no separation or precipitation is observed. Here, "semi-transparent or cloudy" means that the absorbance at a wavelength of 500 nm is 1.0 or higher. ×: Separation or precipitation is observed in the insecticide composition. 【0030】 The evaluation results for nonionic surfactants are shown in Table 1. From Table 1, it can be seen that in the case of nonionic surfactants, if the HLB value is 9.0 or higher, it is possible to formulate the insecticide composition so that separation or precipitation does not occur even when left standing at 20°C for 24 hours. Therefore, in the following examples, nonionic surfactants with an HLB value of 9.0 or higher were used for evaluation. 【0031】 [Table 1] 【0032】 [Preparation of insecticide compositions] An insecticide composition was prepared by combining (A) an insecticide component, (B) a surfactant, (C) an additive, and (D) water. (A) Etofenprox was used as the insecticide component, and (B) the nonionic surfactant, anionic surfactant, and cationic surfactant shown below were used as the surfactant. 【0033】 (1) Nonionic surfactants • Polyoxyethylene hydrogenated castor oil (average number of moles added to EO: 40) • Polyoxyethylene lauryl ether (average number of moles added to EO: 9) • Polyoxyethylene styrene-derived phenyl ether (2) Anionic surfactants • Polyoxyethylene styrene-derived phenyl ether sulfate ammonium (average number of moles added to EO: 13) (3) Cationic surfactants • Lauryldimethylbenzylammonium chloride 【0034】 The stability of the insecticide compositions was evaluated by adding an organic acid salt as additive (C) to (A) and (B) above (Table 2, Examples 1-14). As comparative examples, insecticide compositions without additive (C) were prepared and evaluated (Table 2, Comparative Examples 1-5). Furthermore, insecticide compositions with an organic acid as additive (C) were prepared and evaluated (Table 2, Comparative Example 6). The stability of the insecticide compositions was evaluated in accordance with the evaluation criteria for "Evaluation of Nonionic Surfactants" described above. The evaluation results are shown in Table 2. 【0035】 [Table 2] 【0036】 Furthermore, insecticide compositions were prepared by adding an inorganic salt or alkaline agent as additive (C) to (A) and (B) above, and their stability was evaluated (Table 3, Examples 15-28). In addition, insecticide compositions were prepared by adding a chelating agent as additive (C) to (A) and (B) above, and their stability was evaluated according to the evaluation criteria for "Evaluation of Nonionic Surfactants" described above (Table 4, Examples 29-37). 【0037】 [Table 3] 【0038】 [Table 4] 【0039】 (A) Insecticide compositions were prepared using metofluthrin or cyfluthrin instead of etofenprox as the insecticidal component, and their stability was evaluated (Table 5, Examples 38-39, Comparative Examples 7-8). In Table 5, (B) polyoxyethylene hydrogenated castor oil (average EO addition moles 40), a nonionic surfactant, was used as the surfactant, and (C) sodium citrate, an organic acid salt, was used as the additive. 【0040】 [Table 5] 【0041】 [Evaluation Results] As shown in Tables 2 to 4, insecticide compositions (Examples 1 to 39) formulated with various surfactants and additives exhibit improved low-temperature stability compared to (C) compositions without additives (Comparative Examples 1 to 8). Therefore, the amount of surfactants used that have high solubilizing power and can solubilize insecticidal components on their own can be reduced, thus reducing costs. 【0042】 Furthermore, surfactants known for effects other than solubilization, such as cationic surfactants with antibacterial properties, sometimes could not be used alone due to insufficient solubilizing power. However, by incorporating additives, it becomes possible to solubilize insecticide compositions while also obtaining secondary effects. 【0043】 (A) Metofluthrin, used as the insecticide, is a room-temperature volatile insecticide. Here, room-temperature volatility means that the vapor pressure at 30°C is 2 × 10⁻⁶. -4 ~1 × 10 -2 This means it is in mmHg. Etofenprox and cyfluthrin have a vapor pressure of 2 × 10 at 30°C. -4 It is a non-volatile insecticide component with a concentration of less than mmHg. From Examples 1, 38, and 39, it was confirmed that (A) the insecticide component may be either a volatile insecticide component at room temperature or a non-volatile insecticide component. 【0044】 Although embodiments of the present invention have been described above, the scope of the present invention is not limited thereto, and various modifications can be made without departing from the spirit of the invention. For example, in Tables 2 to 5, (A) insecticide component, (B) surfactant, and (C) additive were each combined and formulated as one type each, but this is not limited to this, and multiple types of at least one of (A) to (C) can be used. The constituent elements disclosed in the embodiments and examples are combinable with each other, and by combining them, new technical features can be formed.

Claims

[Claim 1] An insecticide composition comprising (A) an insecticidal component, (B) a surfactant, (C) an additive, and (D) water, wherein the (C) additive is one or more selected from the group consisting of organic acid salts, alkaline agents, inorganic salts, and chelating agents. [Claim 2] The insecticide composition according to claim 1, comprising at least a pyrethroid compound as the (A) insecticidal component. [Claim 3] The insecticide composition according to claim 1 or 2, wherein the amount of surfactant (B) is such that the composition containing (A), (B), and (D) but without (C) does not separate or precipitate after being left to stand at 20°C for 24 hours.

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