Pest repellent emulsion composition for human use

Abstract

To provide a pest repellent emulsion composition for human use free from scattering of repellent active ingredients, capable of uniformly coating on not only limbs and arms, but also on face and the nape of the neck, less in stiff feeling and feeling of stimulation of a skin after coating, excellent in retentivity of the evasion effective component, and excellent in stability in time.SOLUTION: The insect repellent emulsion composition for human use contains a repellent-effective ingredient, one or two nonionic surfactants selected from the group consisting of glycerol fatty acid esters and polyoxyethylene fatty acid esters, and water (excluding aerosol agents).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present disclosure relates to a pest repellent emulsion composition for human use, and more particularly to a pest repellent emulsion composition for human use that does not scatter the active repellent ingredient, can be applied evenly and without unevenness not only to the hands and feet but also to the face and neck, causes little tightness or irritation to the skin during use, has excellent retention of the active repellent ingredient, and is stable over time. [Background technology]

[0002] Conventionally, DEET has been widely used as the active ingredient (repellent active ingredient) in repellents (pest repellents) for use on the skin against pests such as mosquitoes. However, DEET is highly volatile and has a low retention time when applied to the skin, which means that such repellents have a problem of low durability. Therefore, studies are being conducted on repellents with excellent durability. For example, Patent Document 1 proposes a method using DEET and hexyl laurate, and Patent Document 2 proposes a method of blending an emulsifier composition with DEET.

[0003] Furthermore, repellents that are sprayed onto the skin in liquid form such as aerosols or mists often contain high concentrations of ethanol or polyhydric alcohols to improve the solubility and dispersibility of the active repellent ingredients and the stability of the formulation. For example, icaridin and DEET are poorly soluble in water but soluble in ethanol, so adding ethanol improves the stability of the formulation.

[0004] However, repellents containing ethanol have the problem that the active ingredient does not easily remain on the skin when applied to the skin, and the inclusion of ethanol can cause irritation and dry, tight skin sensations depending on the user.

[0005] Repellents containing polyhydric alcohols require a high concentration of polyhydric alcohol to achieve a stabilizing effect, which can cause a sticky or slimy feeling when applied to the skin, making them difficult to use. Furthermore, as with ethanol-containing repellents, users may experience irritation. Patent Document 3 proposes an ethanol-free repellent in which the amount of polyhydric alcohol added is minimized. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-012414 [Patent Document 2] Japanese Patent Application Publication No. 11-1404 [Patent Document 3] Japanese Patent Application Publication No. 2019-26603 Summary of the Invention [Problem to be solved by the invention]

[0007] Many conventional repellents are in aerosol or mist form, and consumers can experience irritation when inhaling the repellent active ingredients that are dispersed during use. They can also be inconvenient due to dripping during use, and some product labels include instructions not to use on the face (around the eyes and mouth) or neck. Furthermore, some repellents can have a distinctive tight feeling on the skin, making them uncomfortable to use.

[0008] In addition, in order to uniformly emulsify and disperse the active repellent ingredients, it is necessary to add high concentrations of higher alcohols or polyhydric alcohols, which can result in a sticky or slimy feeling when the repellent is applied to the skin, making it unpleasant to use.

[0009] For the reasons described above, preparations containing high concentrations of repellent active ingredients that are excellent in repellent effect and can claim long-lasting effects contain high concentrations of surfactants, higher alcohols, and polyhydric alcohols, which can cause a sticky or slimy feeling during use and a tight feeling on the skin after application.As a result, it has been difficult to obtain a repellent that is easy to use and has a good feel, and also contains a high concentration of repellent ingredients.

[0010] The present disclosure has been made in consideration of the above points, and an object thereof is to provide a pest repellent emulsion composition for human use which does not scatter, can be applied evenly and uniformly not only to the hands and feet but also to the face and neck, causes little sticky or slimy feeling during application, and makes the skin feel tight after application, has excellent retention of the repellent active ingredient, does not separate even when stored for a long period of time, and has good stability. [Means for solving the problem]

[0011] The present invention has the following aspects.

[0012] (1) The pest repellent for human use can include an active repellent ingredient (a), two or more nonionic surfactants (b) selected from the group consisting of glycerin fatty acid esters and polyoxyethylene fatty acid esters, a water-soluble polymer (c), and water.

[0013] (2) The repellent active ingredient (a) may be at least one selected from the group consisting of icaridin and DEET.

[0014] (3) The one or more nonionic surfactants (b) selected from the group consisting of glycerin fatty acid esters and polyoxyethylene fatty acid esters may have an HLB of 8 to 19 or 9 to 16, and the concentration range may be 8 to 24% by mass or 9 to 20% by mass.

[0015] (4) The concentration of the water-soluble polymer (c) may be 0.01 to 2% by mass, or 0.01 to 1% by mass, based on the total mass of the pest repellent for human use.

[0016] (5) The concentration ratio (R=b / a) of the concentration of one or more nonionic surfactants (b) selected from the group consisting of glycerin fatty acid esters and polyoxyethylene fatty acid esters to the concentration of the repellent active ingredient (a) may be R=0.5 to 2.0, or R=0.6 to 1.6.

[0017] (6) The glycerin fatty acid ester may be an ester of glycerin and a fatty acid, the fatty acid having 12 or more carbon atoms, and the HLB of the glycerin fatty acid ester may be 8 or less.

[0018] (7) The polyoxyethylene fatty acid ester may be an ester of polyethylene glycol and a fatty acid, the fatty acid having 12 or more carbon atoms, and the POE fatty acid ester having an HLB of 9 or more.

[0019] (8) The concentration of the repellent active ingredient (a) may be in the range of 5 to 30% by mass, 5 to 25% by mass, or 5 to 20% by mass. Other ingredients may also be contained. [Effects of the Invention]

[0020] The pest repellent for human use according to the present disclosure does not scatter during use, can be applied evenly and without unevenness not only to the hands and feet but also to the face and neck, leaves little sticky or slimy feeling during application, and leaves the skin feeling tight after application. It has excellent retention of the repellent active ingredient, does not separate even when stored for a long period of time, and has good stability. DETAILED DESCRIPTION OF THE INVENTION

[0021] Hereinafter, preferred embodiments of the present invention will be described in detail. Note that the following description of preferred embodiments is merely exemplary in nature and is not intended to limit the present invention, its applications, or its uses.

[0022] The human pest repellent according to this embodiment contains an active repellent ingredient (a), one or more nonionic surfactants (b) selected from the group consisting of glycerin fatty acid esters and polyoxyethylene fatty acid esters, a water-soluble polymer (c), and water. The water may be, for example, purified water. The human pest repellent may contain other ingredients as needed. The human pest repellent may be distributed on the market as a pest repellent product, for example, in a container. The container may be, for example, a spray container, an aerosol container, or the like. In the case of an aerosol container, a propellant for spraying the human pest repellent is also contained therein.

[0023] <Repellent active ingredient (a)> The repellent active ingredient (a) is an ingredient that has a repellent effect against pests, such as mosquitoes.

[0024] The repellent active ingredient (a) may be any ingredient that has a repellent effect against pests, and is not particularly limited. Examples thereof include icaridin, DEET (diethyltoluamide), 3-(Nn-butyl-N-acetyl)aminopropionic acid ethyl ester (IR3535), p-menthane-3,8-diol, 2-ethyl-1,3-hexadiol, butyl 3,4-dihydro-2,2-dimethyl-4-oxo-2H-pyran-6-carboxylate, n-hexyltriethylene glycol monoether, methyl 6-n-pentyl-cyclohexene-1-carboxylate, dimethyl phthalate, eucalyptol, Examples of pest repellent ingredients include α-pinene, geraniol, citronellal, camphor, linalool, terpenol, carvone, dioctyl phthalate, dibutyl phthalate, naphthalene, cinnamon, camphor, lemongrass, clover, thyme, geranium, bergamot, laurel, pine, red peach, benny royal, eucalyptus, and Indian sedan; and pyrethroid insecticide compounds such as natural pyrethrins, pyrethrins, allethrin, phthalthrin, resmethrin, furamethrin, phenothrin, permethrin, cyphenothrin, prallethrin, etofenprox, empenthrin, and transfluthrin. Any one of these may be used alone, or any two or more may be used in combination (mixed).

[0025] As the repellent active ingredient (a), a repellent active ingredient that is poorly soluble in water but soluble in ethanol can be used in terms of usefulness. Examples of such repellent active ingredients (a) include icaridin, DEET (diethyltoluamide), 3-(Nn-butyl-N-acetyl)aminopropionic acid ethyl ester (IR3535), p-menthane-3,8-diol, etc. Among these, icaridin or DEET can be used in terms of the feel and effect when applied to the skin.

[0026] <Nonionic surfactant (b)> The nonionic surfactant (b) is one or more selected from the group consisting of glycerin fatty acid esters and polyoxyethylene fatty acid esters. The one or more nonionic surfactants (b) uniformly emulsify and disperse the repellent active ingredient (a), thereby contributing to improving the stability of the pest repellent for human use.

[0027] The glycerin fatty acid ester used in this embodiment is not particularly limited, but examples thereof include esters of glycerin and fatty acids, in which at least one hydroxyl group of glycerin is esterified with a fatty acid. Specific examples of glycerin fatty acid esters include glyceryl laurate, glyceryl myristate, glyceryl palmitate, glyceryl stearate, glyceryl oleate, glyceryl behenate, and glyceryl caprate.

[0028] The number of carbon atoms in the fatty acid may be 12 or more, or may be 14 to 22. Furthermore, the HLB of the glycerin fatty acid ester may be 8 or less, or may be 2 to 7.

[0029] The polyoxyethylene fatty acid ester used in this embodiment is an ester of polyethylene glycol having an average repeating polyoxyethylene group (average number of moles of ethylene oxide added) and a fatty acid, in which at least one hydroxyl group of the polyethylene glycol is esterified with a fatty acid. Hereinafter, "polyoxyethylene" will also be referred to as "POE."

[0030] Specific examples of POE fatty acid esters used in this embodiment include polyethylene glycol laurate (120 E.O.), polyethylene glycol myristate (150 E.O.), polyethylene glycol palmitate (150 E.O.), polyethylene glycol stearate (150 E.O.), polyethylene glycol distearate (150 E.O.), polyethylene glycol distearate (250 E.O.), and the like.

[0031] The number of carbon atoms of the fatty acid may be 12 or more, or may be 14 to 22. The number of POE may be 10 to 250, or may be 100 to 200. Furthermore, the HLB of the POE fatty acid ester may be 9 or more, or may be 10 to 20.

[0032] The HLB of the nonionic surfactant (b) used in this embodiment, which is one or more selected from the group consisting of glycerin fatty acid esters and polyoxyethylene fatty acid esters, can be 8 to 19, or may be 9 to 16.

[0033] HLB stands for Hydrophile-Lipophile Balance, which means the relative strength of the hydrophilic and lipophilic properties of a surfactant molecule, and is a quantitative expression of this balance. The HLB of a nonionic surfactant can be calculated from the organic and inorganic values ​​of its molecular structure using the following formula (1):

[0034] Furthermore, the mixed HLB of one or more nonionic surfactants can be calculated by the following formula (2).

[0035] HLB value of nonionic surfactant = Σ inorganic / Σ organic × 10 (1) HLB value of two or more nonionic surfactants = HLB1 W1 + HLB2 W2 + (2) HLB1, HLB2: HLB values ​​of nonionic surfactants W1, W2: Weight fraction of nonionic surfactant (W1 + W2 = 1)

[0036] <Water-soluble polymer (c)> The water-soluble polymer (c) used in this embodiment acts on the adsorption layer of the emulsified and dispersed aggregates, contributing to the stabilization of the aggregates due to its steric protection effect and electrostatic repulsion. When the human pest repellent contains the water-soluble polymer (c), the aggregates can be stabilized even with a low surfactant concentration, and changes in viscosity over time can be reduced, aggregation and coalescence of the aggregates can be inhibited, and separation can be prevented even during long-term storage.

[0037] In this specification and claims, the term "water-soluble polymer" refers to a polymer that can be dissolved or dispersed in water and thicken an aqueous medium.

[0038] Specific examples of the water-soluble polymer (c) include natural water-soluble polymers such as plant-based polymers such as gum arabic, tamarind gum, tragacanth gum, galactan, guar gum, xanthan gum, carob gum, locust bean gum, karaya gum, carrageenan, pectin, agar, quince seed, algae colloid, and starch, microbial polymers such as dextran, dextrin, succinoglucan, and pullulan, and animal polymers such as collagen, casein, albumin, and gelatin. Specific examples of semi-synthetic water-soluble polymers include starch-based polymers such as carboxymethyl starch and methylhydroxypropyl starch, cellulose-based polymers such as methylcellulose, nitrocellulose, ethylcellulose, methylhydroxypropyl cellulose, hydroxyethyl cellulose, sodium cellulose sulfate, hydroxypropyl cellulose, sodium carboxymethylcellulose (CMC), crystalline cellulose, and cellulose powder, and alginic acid-based polymers such as sodium alginate and propylene glycol alginate. Examples of synthetic water-soluble polymers include vinyl polymers such as polyvinyl alcohol, polyvinyl methyl ether, polyvinylpyrrolidone, and carboxyvinyl polymer (carbomer); polyoxyethylene polymers such as polyethylene glycol (molecular weight 1500, 4000, 6000, etc.); polyoxyethylene-polyoxypropylene copolymer polymers; acrylic polymers such as sodium polyacrylate and polyethyl acrylate; polyethyleneimine; and cationic polymers. Examples of inorganic water-soluble polymers include bentonite, AlMg silicate, laponite, hectorite, and silicic anhydride. These may be used alone or in combination of two or more.

[0039] Among the above-mentioned water-soluble polymers (c), carboxyvinyl polymers are particularly preferred because they act on the adsorption layer of the emulsified / dispersed aggregates and prevent aggregation and coalescence of the aggregates due to their steric protection and thixotropy. The carboxyvinyl polymer is an acrylic acid / alkyl methacrylate copolymer.

[0040] <Other ingredients> The human repellent may contain ingredients (other ingredients) other than those mentioned above. Examples of other ingredients include surfactants other than glycerin fatty acid esters and polyoxyethylene fatty acid ester surfactants. Other examples include additives such as moisturizers, disinfectants and preservatives, thickeners other than water-soluble polymers, pigments, pH adjusters, fragrances, UV absorbers, UV scattering agents, and antioxidants. Any one of these may be used alone, or any two or more may be used in combination.

[0041] The other surfactants are not particularly limited, and known surfactants can be used as appropriate. Specific examples include polyoxyethylene sorbitan fatty acid ester, polyoxyethylene sorbit tetraoleate, polyoxyethylene hydrogenated castor oil, polyoxyethylene polyoxypropylene glycol, etc. These surfactants are preferred because they do not impair the stability of the pest repellent for human use. Any one of these surfactants may be used alone, or any two or more may be used in combination.

[0042] <Concentration of each ingredient> In the pest repellent for human use according to this embodiment, the concentration of the repellent active ingredient (a) can be 5 to 30% by mass relative to the total mass of the pest repellent for human use. The concentration of the repellent active ingredient (a) may also be 5 to 25% by mass, or 5 to 20% by mass. When the concentration of the repellent active ingredient (a) is equal to or greater than the lower limit, the repellent effect against pests is easily exhibited when the pest repellent for human use is applied to the skin. When the concentration is equal to or less than the upper limit, the stability of the pest repellent for human use is improved. Note that, for example, when the specification and claims refer to "5 to 30% by mass," this means "5% by mass or more and 30% by mass or less," and includes the values ​​on both sides of the "to" symbol. The same applies to other terms.

[0043] The concentration of the nonionic surfactant (b) can be 8 to 24% by mass relative to the total mass of the pest repellent for human use. The concentration of the nonionic surfactant (b) may be 9 to 20% by mass. If the concentration of the nonionic surfactant (b) is less than the above lower limit, the stability of the pest repellent for human use may decrease, and if it exceeds the above upper limit, the feeling of use of the pest repellent for human use may decrease.

[0044] The concentration of the water-soluble polymer (c) can be 0.01 to 2% by mass relative to the total mass of the pest repellent for human use. The concentration of the water-soluble polymer (c) can be 0.01 to 1% by mass. If the concentration of the water-soluble polymer (c) is within the above range, the association is sufficiently stabilized even when the concentration of the nonionic surfactant (b) is low, and the stability of the pest repellent for human use is excellent. If the concentration of the water-soluble polymer (c) is too high or too low, the molecular association may become unstable.

[0045] The concentration ratio R of the nonionic surfactant (b) to the repellent active ingredient (a) can be calculated by (b) / (a). The concentration ratio (R=b / a) can be set to 0.5 to 2.0. The concentration ratio (R=b / a) can also be set to 0.6 to 1.6. If the concentration of the nonionic surfactant (b) is below the lower limit of the above range, the stability of the human pest repellent may decrease, while if it exceeds the upper limit of the above range, the feeling of use of the human pest repellent may decrease and irritation may increase.

[0046] <Method for preparing a pest repellent for human use> The method for preparing the pest repellent for human use according to this embodiment is not particularly limited, and the pest repellent for human use can be prepared, for example, by the following method.

[0047] The repellent active ingredient (a), surfactant (nonionic surfactant (b), and other surfactants as needed), and oil are stirred in a warm bath at about 80°C. Purified water and, if needed, additives are added to this mixture, and after uniform emulsification and dispersion, the mixture is cooled with stirring. After cooling, additives such as water-soluble polymer (c), preservatives, and fragrances are added, and the mixture is further cooled to near room temperature. Examples of preservatives include methylparaben and propylparaben, but other preservatives may also be used.

[0048] <Action and effect> The pest repellent for human use according to this embodiment does not scatter and can be applied evenly and without unevenness not only to the hands and feet but also to the face and neck, leaving little sticky or slimy feeling during use, leaving little tightness on the skin after application, and exhibiting excellent stability and retention of the active repellent ingredient.

[0049] In other words, by using a nonionic surfactant (b) with a specific HLB range as the surfactant, even a repellent active ingredient that is poorly soluble in water, such as icaridin, can be uniformly emulsified and dispersed with a small amount of surfactant, thereby stabilizing a pest repellent for human use.

[0050] Furthermore, by combining a nonionic surfactant (b) with a water-soluble polymer (c), a stable dispersion state can be maintained even when the amount of surfactant is reduced. The water-soluble polymer (c) acts on the adsorption layer of the emulsified and dispersed aggregates, contributing to the stabilization of the aggregates due to its steric protection effect and electrostatic repulsion. Because it has the effect of preventing aggregation and coalescence of the aggregates, by using this in combination, it is thought that it will be possible to prepare a pest repellent for human use that is highly stable even with a small amount of surfactant.

[0051] The repellent effect of a low-volatility active repellent ingredient (a) such as icaridin is reduced mainly by runoff due to sweat or percutaneous absorption, so that suppressing percutaneous absorption can improve retention. Therefore, the present invention is effective for various active repellent ingredients, but is particularly useful when using a low-volatility active repellent ingredient such as icaridin.

[0052] The form of the pest repellent for human use according to this embodiment is not particularly limited, and it can be used in the form of, for example, emulsion, cream, gel, spray, etc. The pest repellent for human use can be stored in a container according to the formulation.

[0053] The human pest repellent according to this embodiment exerts a sufficient repellent effect against pests when applied to the skin, for example. Examples of pests that can be repelled by the human pest repellent according to this embodiment include mosquitoes, black flies, stable flies, house dust mites, bedbugs (cimex lectularius), ticks, chiggers, and fire ants, but the repellent effect is also exerted against pests other than these. [Example]

[0054] The present invention will be explained in more detail below with reference to examples and comparative examples, but the present invention is not limited to these examples.

[0055] <Production Methods of Examples and Comparative Examples> The active repellent ingredient (a) and surfactant (nonionic surfactant (b), optionally other surfactants) and higher alcohol or polyhydric alcohol are stirred in a warm bath at approximately 80°C, and heated purified water is added to the mixture. The mixture is then allowed to cool to 50°C while stirring. A water-soluble polymer and preservative are then added, followed by a neutralizing agent such as sodium hydroxide. The mixture is then stirred and cooled to room temperature. Examples of higher alcohols include isostearyl alcohol and octyldodecanol, although other higher alcohols may also be used. Examples of polyhydric alcohols include glycerin, 1,3-butylene glycol, and propylene glycol, although other polyhydric alcohols may also be used.

[0056] The "balance" of purified water in Tables 1 to 3 indicates the amount that makes the total amount of the pest repellent for human use 100% by mass.

[0057] [Table 1]

[0058] [Table 2]

[0059] [Table 3]

[0060] <Stability test evaluation> The pest repellents for human use (Examples 1 to 28, Comparative Examples 1 to 8) prepared by the above-mentioned preparation method were stored for one month at room temperature (RT), -5°C, and 50°C, respectively. The condition (appearance) of each pest repellent for human use after storage was visually evaluated, and stability was evaluated according to the following criteria. The results are shown in Tables 1 to 3. In Examples 1 to 28, there was no separation over a wide temperature range and the repellents were uniformly emulsified and dispersed, whereas in Comparative Examples 1 to 8, oil droplets were present in the liquid or separation into two phases was observed.

[0061] (Evaluation criteria) ◯: No separation, uniformly emulsified and dispersed. △: Partially emulsified and dispersed, but oil droplets remain. ×: Separated into two phases.

[0062] <Scattering evaluation> The human pest repellent was applied evenly to the inside of the forearm of five subjects, and scattering was evaluated based on the subjects' evaluation results using the following criteria. The results are shown in Table 4. No scattering was observed with Example 3, but scattering was observed with Commercial Products A and B. Commercial Product A is an aerosol product, Commercial Product B is a pump mist product, and Commercial Product C is a gel product.

[0063] (Evaluation criteria) 〇: All five participants did not feel any dust flying around. ×: One or more people felt the dust flying.

[0064] [Table 4]

[0065] <Evaluation of ease of uniform application> The human pest repellent was applied to the inside of the forearm of five subjects, and the ease of uniform application was evaluated based on the subjects' evaluation results using the following criteria. The results are shown in Table 4, and Example 3 was easy to apply uniformly.

[0066] (Evaluation criteria) 〇: All five people felt that it was easy to apply evenly. ×: One or more people found it difficult to apply evenly.

[0067] <Skin irritation evaluation> The human pest repellent was applied evenly to the inside of the forearm of five subjects, and the irritation sensation was evaluated based on the subjects' evaluation results using the following criteria. The results are shown in Table 4. No irritation was felt on the skin with Example 3, but irritation was felt with commercially available products A to C.

[0068] (Evaluation criteria) 〇: All five participants felt no irritation. ×: One or more people felt irritation.

[0069] <Skin tightness evaluation> The human pest repellent was applied evenly to the inside of the forearm of five subjects, and the subjects' evaluation results were used to evaluate the skin's feeling of tightness after application according to the following criteria. The results are shown in Table 4. Example 3 did not cause any skin tightness, but commercial products A to C caused skin tightness.

[0070] (Evaluation criteria) 〇: All five subjects did not feel any tightness on their skin. ×: One or more people felt a tight feeling on the skin.

[0071] <Test for sustained blood-sucking prevention effect (pest repellent test)> The human pest repellent was evenly applied to the inside of the forearm of five subjects, and a syringe containing 10 female Aedes albopictus mosquitoes was pressed against the skin for 1 minute after each time period (10 hours, 5 hours, and before 5 hours), and the number of mosquitoes that bitten was counted to measure and evaluate the repellent effect. The results are shown in Table 4. In Example 3, a 90% blood-sucking prevention rate was confirmed even 10 hours after application, but in the case of commercial products A to C, the blood-sucking prevention rate fell below 90% 5 hours after application.

[0072] (Evaluation criteria) 〇: 90% blood-sucking prevention effect confirmed after 10 hours △: 90% blood-sucking prevention effect confirmed after 5 hours ×: 90% blood-sucking prevention effect confirmed in less than 5 hours

[0073] As shown in Table 1, the pest repellents for human use in Examples 1 to 9 were able to uniformly emulsify and disperse the repellent active ingredient, including icaridin, when the concentration of the oil-based repellent active ingredient was in the range of 5 to 30% by mass, and the stability test results after one month were also good. Furthermore, when the concentration ratio (R=b / a) of the nonionic surfactant (b) to the repellent active ingredient (a) was in the range of 0.5 to 2.0, the repellent active ingredient was uniformly emulsified and dispersed, and the stability test results after one month were also good.

[0074] On the other hand, even when the concentration ratio R was within the range of 0.5 to 2.0, as in Comparative Examples 1 to 3, when the concentration of the repellent active ingredient was 40 mass% or more and water-soluble polymer (c) was not added, the appearance immediately after preparation was heterogeneous, and the stability test results after one month were also poor.

[0075] In the human pest repellents of Examples 4 and 5, the nonionic surfactant (b) was a glycerin fatty acid ester alone or a polyoxyethylene fatty acid ester alone, but it was possible to uniformly emulsify and disperse the repellent active ingredient, and the stability test results after one month were also good.

[0076] The pest repellent for human use in Example 6 contains DEET as an active repellent ingredient, and DEET was uniformly emulsified and dispersed in the same manner as icaridin, and the stability test after one month showed good results.

[0077] As shown in Table 2, in Examples 10 to 16, in which the mixed HLB value of the nonionic surfactant (b) was in the range of 9 to 16, the repellent active ingredient was uniformly emulsified and dispersed, and the stability test results after one month were also good. However, in Comparative Examples 4 and 5, in which the mixed HLB value was 8 or less, the appearance immediately after blending was uniformly emulsified and dispersed, but the stability after one month was poor.

[0078] Furthermore, as in Comparative Examples 6 to 8, even when the mixed HLB value was within the range of 9 to 16, when the concentration ratio (R=b / a) of the nonionic surfactant (b) to the repellent active ingredient (a) was 0.5 or less, the stability test after one month was poor.

[0079] From the above results, it can be seen that if the mixed HLB value of the nonionic surfactant (b) is within the range of 8 to 19 or 9 to 16, and the concentration ratio of the nonionic surfactant (b) to the repellent active ingredient (a) (R=b / a) is 0.5 to 2.0 or R=0.6 to 1.6, the repellent active ingredient can be uniformly emulsified and dispersed, and the stability test after one month also shows good results.

[0080] As shown in Table 3, the human pest repellents of Examples 17 to 20 contain CMC (hydroxymethylcellulose), HEC (hydroxyethylcellulose), xanthan gum, and cationized guar gum as water-soluble polymers, and all of them were able to produce uniform emulsions, and stability tests after one month showed good results.

[0081] The human pest repellents of Examples 21 to 23 contain other surfactants such as POE sorbitan fatty acid ester, POE sorbit tetraoleate, and POE hydrogenated castor oil, and all of them produced uniform emulsions, and the stability test after one month showed good results.

[0082] Furthermore, the pest repellents for human use in Examples 24 to 28 contained higher alcohols or polyhydric alcohols as additives, but all of them were able to produce uniform emulsions, and the stability test after one month showed good results.

[0083] As shown in Table 4, the human pest repellent of Example 3 did not scatter the active ingredient of the repellent, caused less irritation during use, and was easy to apply evenly not only to the hands, feet, and arms, but also to the face and neck, compared to commercial products A and B.

[0084] Furthermore, compared to commercially available product C, the human pest repellent of Example 3 dripped less when applied, was easy to apply evenly to the entire body, including the face and neck, had less stickiness or sliminess when used, and did not leave the skin feeling tight after application.

[0085] Regarding the sustained blood-sucking prevention effect, all of the commercially available products A, B, and C lost 90% of their blood-sucking prevention effect in less than 5 hours, but the human pest repellent of Example 3 still maintained 90% of its blood-sucking prevention effect even after 10 hours had passed.

[0086] From the above results, it can be seen that the human pest repellent of Example 3 is easier to apply evenly to the entire body, including the face and neck, is less sticky or slimy during use, does not leave a tight feeling on the skin after application, and furthermore, shows high durability in the blood-sucking deterrent effect test, compared to commercial products A to C. Similarly, for the other examples, it is easier to apply evenly to the entire body, including the face and neck, is less sticky or slimy during use, does not leave a tight feeling on the skin after application, and furthermore, shows high durability in the blood-sucking deterrent effect test, compared to commercial products A to C.

[0087] The above-described embodiments are merely examples in all respects and should not be construed as limiting. Furthermore, all modifications and variations within the scope of the claims are within the scope of the present invention. [Industrial Applicability]

[0088] As explained above, the pest repellent for human use according to the present invention can be used to repel pests such as mosquitoes, black flies, stable flies, house dust mites, bedbugs (cimex lectularius), ticks, chiggers, and fire ants, and can be used, for example, as an insect repellent to be applied to human skin, or to the epidermis of pets or livestock.

Claims

1. A pest repellent emulsion composition for human use (excluding aerosols) comprising an active repellent ingredient (a), at least one or more nonionic surfactants (b) selected from the group consisting of glycerin fatty acid esters and polyoxyethylene fatty acid esters, and water.

2. 2. The pest repellent emulsion composition for human use according to claim 1, wherein the repellent active ingredient (a) is at least one selected from the group consisting of icaridin and DEET.

3. The emulsified composition of a pest repellent for human use, wherein the total concentration of the nonionic surfactant (b) is in the range of 8 to 24 mass %.

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