Title of Invention: Pest Repellent Composition
Technical field
[0001]
　The present invention relates to a pest repellent composition containing a pest repellent component, a solvent and porous particles. In particular, the present invention relates to a pest repellent composition that achieves both suppression of percutaneous absorption of pest repellent components and stabilization of volatilization.
Background technology
[0002]
　Insect repellents containing pest repellent ingredients are used to protect the human body from pests such as mosquitoes, gnats, fleas, fleas, house dust mites, stable flies, bed bugs and mites. Even pest repellent ingredients (DEET, picaridin, etc.) that are approved for application to the skin need to reduce irritation to the skin. For example, when DEET is applied to the skin, about 50% of it has been reported to be transdermally absorbed within 6 hours. That is, by suppressing percutaneous absorption, it is possible to enhance the sustainability of the pest repellent effect and reduce the irritation given to the skin.
[0003]
　Therefore, a pest repellent composition containing a pest repellent component, silicic anhydride, a propellant, and a solvent is known (see, for example, Patent Document 1). According to this composition, since the pest repellent component is taken into the pores of the silicic anhydride, it is possible to prevent the pest repellent component from volatilizing. In addition, since the area where the pest repellent component comes into direct contact with the skin is reduced, the irritation given to the skin can be reduced and the stickiness can be reduced.
[0004]
　Further, a pest repellent composition in which a pest repellent component is impregnated in micropores or voids of a porous organic powder is known (see, for example, Patent Document 2).
Prior art literature
Patent documents
[0005]
Patent Document 1: Japanese Patent Application Laid-Open No. 9-208406
Patent Document 2: Japanese Patent Application Laid-Open No. 6-271402
Outline of the invention
Problems to be solved by the invention
[0006]
　Patent Document 1 states that a pest repellent component is incorporated into the pores of silicic anhydride. However, silicon dioxide having a pore volume of 1 mL / g or less cannot sufficiently prevent the volatilization of the pest repellent component and the stickiness of the pest repellent composition because the amount of the pest repellent component taken up is small.
[0007]
　Further, the aerosol agent of Patent Document 2 contains a porous organic powder impregnated with a pest repellent component in the voids. However, as an aerosol agent, a solvent such as ethanol that dissolves a pest repellent component is often used as a diluent. In this case, a mixed solution of the pest repellent component and the solvent is contained in the porous organic powder. Excess pest repellent components that cannot fit in the pores are applied to the skin as a liquid phase. Therefore, the effects of reducing stickiness and reducing evaporation of pest repellent components could not be sufficiently obtained. In addition, some pest repellent components such as DEET have a strong action of dissolving plastic products. Therefore, if the plastic product is touched while it exists as a liquid phase on the skin, the plastic product may be deteriorated or the appearance may be deteriorated.
Means to solve problems
[0008]
　Therefore, the pest repellent composition of the present invention contains porous particles in which primary particles containing silica form pores and aggregate, a pest repellent component, and a solvent. The ratio (I 1 / I 2 ) of the maximum absorbance (I 1 ) of 3730 to 3750 cm -1 and the maximum absorbance (I 2 ) of 1160 to 1260 cm -1 in the infrared absorption spectrum of the porous particles is 0. It is 005 or less.
[0009]
　According to such a pest repellent composition, the pest repellent component applied to the skin can be efficiently absorbed into the pores of the porous particles, and the pest repellent component in contact with the skin can be reduced. This suppresses transdermal absorption.
[0010]
　In addition, since the pest repellent component volatilizes from the porous particles that have absorbed the pest repellent component at the equivalent of vapor pressure, the pest repellent effect is continuously exhibited. However, when the particles absorb moisture (when water adheres to the surface of the particles), the volatilization of the pest repellent component is inhibited. Therefore, in order to maintain stable volatilization for a long time, it is necessary to prevent water from adhering to the particle surface. Since the absorbance ratio (I 1 / I 2 ) of the porous particles is 0.005 or less, the hydrophilicity of the particle surface is low, and the adsorption of water can be prevented.
[0011]
　Further, the pore volume (PV) of the porous particles was set in the range of more than 1.0 to 5.0 mL / g, and the average pore diameter (PD) was set in the range of 0.005 to 0.5 μm.
[0012]
　Further, in order to keep the volatilization rate of the pest repellent component constant, the hygroscopicity of the porous particles was set to 10% or less. The aperture ratio of the pores was set to 20 to 75%. Further, the ratio (PD / VP) of the average pore diameter PD [μm] of the porous particles to the vapor pressure VP [Pa] of the pest repellent component at 20 ° C. was set to 500 or less.
Effect of the invention
[0013]
　According to the pest repellent composition of the present invention, the pest repellent component applied to the skin is efficiently absorbed by the pores of the porous particles, and the pest repellent component in contact with the skin is reduced. This suppresses transdermal absorption. Furthermore, since the surface of the porous particles is less hydrophilic, moisture absorption does not inhibit the volatilization of the pest repellent component. Therefore, a stable repellent effect can be maintained for a long time.
Mode for carrying out the invention
[0014]
　The pest repellent composition of the present invention contains porous particles, a pest repellent component and a solvent. Porous particles are particles formed by aggregating primary particles containing silica as a component, and have pores formed by voids between the primary particles. The porous infrared absorption spectrum of the particles were measured, 3730 ~ 3750Cm -1 maximum absorbance (I in 1 and), 1160 ~ 1260 cm -1 maximum absorbance (I 2 obtains a). At this time, the absorbance ratio (I 1 / I 2 ) is 0.005 or less. When such a pest repellent composition is applied to the skin, the pest repellent component is efficiently absorbed by the pores of the porous particles on the skin, and the pest repellent component in contact with the skin is reduced. Therefore, transdermal absorption can be suppressed, and adverse effects on plastic products can also be suppressed. Further, since the absorbance ratio (I 1 / I 2 ) of the porous particles is 0.005 or less, the hydrophilicity of the particle surface is low. Therefore, it is difficult for water to be adsorbed on the particles, and the evaporation of the pest repellent component is not hindered. In this way, both suppression of percutaneous absorption of pest repellent components and stabilization of volatilization can be achieved. As a result, the repellent effect is stably exhibited for a long period of time.
[0015]
　Here, the absorbance ratio (I 1 / I 2 ) depends on the amount of silanol groups on the particle surface. When the silanol groups (Si—OH) on the particle surface decrease, the infrared absorbance at 3730 to 3750 cm -1 decreases, while the infrared absorptivity at 1160 to 1260 cm -1 attributed to the siloxane bond (Si—O—Si) increases. Become. Since silanol groups bind to water, the fewer silanol groups there are, the lower the hydrophilicity. That is, it can be said that the smaller the absorbance ratio (I 1 / I 2 ), the lower the hydrophilicity of the particle surface. In order to reduce the absorbance ratio, surface treatment with a silane compound or the like, high-temperature firing, or the like may be performed to reduce silanol groups and make the surface hydrophobic.
[0016]
　For this surface treatment, it is preferable to use a low molecular weight silane compound having a molecular weight of 500 or less. A high molecular weight silane compound can also be made hydrophobic by binding to a silanol group, but since the high molecular weight silane compound has a large molecule, it prevents other silane compound molecules from binding to a nearby silanol group, and unbonded silanol. Many groups may remain (three-dimensional disorder). If silanol groups remain, a minimal hydrophilic phase may be formed here. Therefore, it is preferable to use a low molecular weight silane compound to reduce the number of unbonded silanol groups. Furthermore, the small-sized low-molecular-weight compound easily binds to the silanol groups in the pores, and can impart hydrophobicity to the surface in the pores.
[0017]
　The pore volume of such porous particles is larger than 1.0, preferably 5.0 mL / g or less. When the pore volume is large, many pest repellent components can be contained, so that the repellent effect is sustained. In addition, since the pest repellent component is retained in the voids (pores) in the porous particles, the repellent component does not come into direct contact with the skin, and transdermal absorption is suppressed. Therefore, the repellent effect can be exhibited for a long time.
[0018]
　The average pore size (PD) of the porous particles is preferably in the range of 0.005 to 0.5 μm. If the pore size is small, the volatilization of the pest repellent component is suppressed, and the repellent effect itself may be reduced. Further, if the pore diameter is too large, the volatilization of the pest repellent component is promoted, and the sustainability of the repellent effect may decrease. The range of more than 0.010 to 0.4 μm is particularly preferable.
[0019]
　Further, the hygroscopicity of the porous particles when they are allowed to stand for 24 hours under the conditions of a temperature of 80 ° C. and a relative humidity of 80% is preferably 10% or less. As described above, such porous particles having a low hygroscopicity do not inhibit the volatilization of the pest repellent component, and a stable repellent effect can be obtained. It is more preferably 5% or less, still more preferably 1% or less.
[0020]
　Although such porous particles are hydrophobic with a contact angle of more than 90 ° with respect to water, the contact angle with respect to a repellent component is in the range of 1 ° to 90 °. Therefore, the porous particles do not absorb moisture, the volatilization of the repellent component is not inhibited, and a stable repellent effect is exhibited.
[0021]
　Further, the volatilization rate of the pest repellent component can be controlled by adjusting the aperture ratio of the pores and the size of the average pore diameter in the porous particles according to the vapor pressure of the pest repellent component. The vapor pressure of the pest repellent component at 20 ° C. V P When [Pa], an average pore diameter PD of the porous particles ([mu] m) and the vapor pressure V P ratio of [Pa] (PD / VP) is less than 500 Is preferable. Within this range, rapid volatilization can be prevented and a sustained repellent effect can be obtained. Furthermore, the volatilization of the pest repellent component is not inhibited. The aperture ratio of the pores on the particle surface is preferably 20 to 75%. If the aperture ratio is less than 20%, the evaporation of the pest repellent component is inhibited, and a stable repellent effect cannot be achieved. If the aperture ratio exceeds 75%, the strength of the porous particles is weakened, and the particles may collapse during the compounding process into the preparation.
[0022]
　Incidentally, contained in the pest repellent composition, the vapor pressure V at 20 ° C. in a solvent composed mainly PS vapor pressure V at 20 ° C. of [Pa] and pest repellent component P ratio of [Pa] (V PS / V P ) 1000 or more is suitable. Within this range, the composition is applied to the skin to form a film of a mixture of solvent, pest repellent component and porous particles, after which the solvent immediately volatilizes to form a film of pest repellent component and porous particles. Become. Since the solvent absorbed inside the porous particles also volatilizes, empty pores are created, and the repellent component is absorbed here. In order to suppress the percutaneous absorption of the repellent component, it is desirable to select the solvent so that the above vapor pressure ratio becomes high. The vapor pressure ratio is preferably 2000 or more, and more preferably 3000 or more.
[0023]
　As the solvent, either one that can dissolve the pest repellent component or one that cannot dissolve the pest repellent component can be used, but lower alcohols such as ethanol and denatured ethanol are often used.
[0024]
　Further, the average particle size of the porous particles is preferably 0.5 to 20 μm. If it is within this range, a smooth feeling can be obtained at the time of application. The compressive strength of the porous particles is preferably 0.1 to 100 KPa. When the repellent composition containing the porous particles is spread on the skin by hand, the porous particles disintegrate into the primary particles and adhere to the skin. Therefore, even if there is moisture such as sweat or rain, it is difficult for the skin to fall off. Therefore, the repellent effect can be sustained. The average particle size of the primary particles is preferably 0.005 to 1.0 μm.
[0025]
　Further, it is preferable that the pest repellent composition contains 1 to 30% by weight of porous particles.
[0026]
　Here, the primary particles constituting the porous particles may contain 10 to 50% by mass of alumina, zirconia, titania, etc. in addition to silica as the main component. Amorphous silica particles are preferable as the primary particles, considering that the porous particles are blended in pharmaceutical products and quasi-drugs.
[0027]
　Examples of the pest repellent component include DEET (N, N-diethyl-m-toluamide), which has been confirmed to be safe for the human body, icaridin, IR3535 (cetyl (butyl) aminopropanoate), and the like. it can. In addition, as pest repellents extracted from naturally derived plants, lemon eucalyptus essential oil and its active compound PMD (p-menthan-3,8-diol), cypress, castor oil, achillea oil, oregano oil, catnip oil , Citronella oil, cinnamon skin oil, cinnamon leaf oil, cedar oil, geranium oil, celery extract, tea tree oil, clove oil, neem oil, garlic oil, hashibamine nut oil, basil oil, fennel oil, peppermint oil, peppermint oil , Marigold oil, lavender oil, lemongrass oil, rosemary oil, thyme oil, eucalyptus oil and mixtures thereof.
[0028]
　The pest repellent composition of the present invention can be applied to any dosage form such as an aerosol preparation, a lotion, and a cream. When applied to aerosol preparations, liquefied petroleum gas such as LPG can be used as a propellant, as needed, as a moisturizer, dispersant, fragrance, pigment, refreshing agent, bactericide, ultraviolet absorber, ultraviolet scattering agent, lubricant, etc. Is added.
[0029]
　Hereinafter, an example using DEET as a pest repellent component will be specifically described.
[0030]
　[Example 1]
　First, SMB LB-1500 (average particle diameter 15 μm, pore volume 1.3 mL / g, pore diameter 12 nm, oil absorption 230 mL / g) manufactured by JGC Catalysts and Chemicals Co., Ltd. was used as raw material particles. To 1.0 kg of the raw material particles, 0.1 kg of hexamethyldisilazane (manufactured by Shin-Etsu Chemical Co., Ltd .: SZ-31, molecular weight: 161.4) and 2.3 kg of methanol (special grade reagent) were added. This mixed solution was mixed at room temperature for 5 hours using a rotary evaporator, and then heated at 120 ° C. for 16 hours. As a result, porous particles surface-treated with a silane compound were obtained. The obtained porous particles have few silanol groups on the surface and are hydrophobized. Next, 8.5 kg of ethanol and 1.3 liters of DEET (manufactured by Tokyo Chemical Industry Co., Ltd.) were added to 1.0 kg of the porous particles, and the mixture was stirred in a closed container for 30 minutes. In this way, a pest repellent composition containing porous particles, a pest repellent component, and a solvent is obtained. This pest repellent composition contains 12% by weight of DEET, 79% by weight of ethanol, and 9% by weight of porous particles. The following physical properties were measured using these porous particles and the pest repellent composition as samples. The results are shown in Tables 1 and 2.
[0031]
　(1) Absorbance ratio
　The infrared absorption spectrum of porous particles was measured using FT-IR6300 (manufactured by JASCO Corporation), and a graph showing the relationship between the wave number (cm -1 ) and the absorbance calculated by the Kubelkamunck formula was created. did. From the resulting graph, 3730 ~ 3750Cm -1 maximum absorbance (I in 1 ) and 1160 ~ 1260 cm -1 maximum absorbance (I 2 reads), absorbance ratio (I 1 / I 2 was calculated).
[0032]
　(2) Contact angle After
　1 g of the porous particles are dried at 200 ° C., they are placed in a cell having a diameter of 1 cm and a height of 5 cm and pressed with a load of 50 kgf to prepare a molded product. A drop of water was dropped on the surface of this molded product, and the contact angle with water was measured. Similarly, a drop of DEET was dropped on the surface of the molded product and the contact angle with respect to the pest repellent component was measured.
[0033]
　(3) Pore volume (PV), average pore size (PD)
　Take 10 g of porous particle powder into a crucible, dry at 300 ° C. for 1 hour, cool to room temperature in a desiccator, and use an automatic porosimeter (counterchrome. The pore size distribution was measured by a mercury intrusion method using a PoreMaster PM33GT manufactured by Instruments. Specifically, mercury is press-fitted at 1.5 MPa to 231 MPa, and the pore size distribution can be obtained from the relationship between the pressure and the pore size. According to this method, mercury is press-fitted into the pores from about 7 nm to about 1000 μm, so that both the small-diameter pores existing inside the porous particles and the gaps between the porous particles have a pore diameter. It is represented by the distribution. The gap between the particles is approximately 1/5 to 1/2 the average particle size of the porous particles. The pore volume and the average pore diameter were calculated based on the pore size distribution depending on the pores, excluding the portion of the porous particles depending on the gap.
[0034]
　(4) Pore opening ratio The
　pore opening ratio is defined by (pore area / analysis area area). An image of 100 to 200 particles randomly selected by taking a SEM (scanning electron microscope) photograph (magnification: 30,000 times) of the porous particle group and using image analysis software for SEM (Scandium manufactured by Olympus Corporation). To analyze. At this time, the photographing magnification may be changed according to the particle diameter so that the particle surface can be photographed over the entire photographed image.
[0035]
　Specifically, a scanning electron microscope (JSM-6010LA manufactured by JEOL Ltd.) is used to acquire a secondary electron image (SEM photograph). Randomly select 100 to 200 particles from this SEM photograph. The image data (secondary electron image, jpg image) of the SEM photograph is read by the image analysis software "Scandium". A specific area is selected as an analysis area (frame) from the image. This analysis area (frame) is binarized. Specifically, 153 gradations are selected as the lower limit value and 255 gradations are selected as the upper limit value of each of the RGB values, and binarization by these two threshold values ​​is executed. The pores in the analysis region where binarization was performed are detected. For the detected pores, determine the analysis area area and pore area. This procedure is repeated until 100-200 porous particles are analyzed.
[0036]
　(5) Average particle size The particle size
　distribution of the porous particles was measured using a laser diffraction method. The median value in this particle size distribution was taken as the average particle size. For the measurement of the particle size distribution by the laser diffraction method, a laser diffraction / scattering type particle size distribution measuring device LA-950v2 (attached to a dry unit, manufactured by HORIBA, Ltd.) was used.
[0037]
　(6) Hygroscopicity
　Take 5 g of powder of porous particles into a crucible (weigh "powder weight" and "crucible weight" to four digits after the decimal point), and set the temperature to 80 ° C and relative humidity to 80%. It was allowed to stand in a wet tank (IG420 manufactured by Yamato Scientific Co., Ltd.) for 24 hours. The "total weight of crucible and powder" after standing was weighed to four digits after the decimal point, and the "powder weight after moisture absorption" was calculated from the total weight. From the result, "hygroscopicity (%)" was calculated by setting "hygroscopicity (%)" = ("powder weight after moisture absorption" ÷ "powder weight") x 100-100.
[0038]
　(7) Inclusion rate of pest repellent component The ratio
　of the amount (mL) of the added pest repellent component to the powder weight (g) of the raw material particles used in the examples is the inclusion rate (mL / g) of the pest repellent component. ).
[0039]
　(8) Reduction rate of
　pest repellent component The pest repellent composition is weighed into a glass chalet (146φ × 28) so that the total amount of the pest repellent component and the porous particles is 1.0 g (V 1 ), and the powder is combined with the powder. The total weight of the glass chalet (V 2 ) was recorded. This was allowed to stand in a constant temperature and humidity chamber (IG420 manufactured by Yamato Scientific Co., Ltd.) set at a temperature of 37 ° C. and a relative humidity of 50%. The total weight (V 3 ) was measured every 5 hours, and the reduction rate of the pest repellent component (after 5 hours) was calculated by the following formula. Similarly, the total weight was measured after 10 hours of standing time, and the reduction rate of the pest repellent component (after 10 hours) was calculated. Assuming that the inclusion rate of the pest repellent component is P 1 (mL / g) and the specific gravity of the included pest repellent component is D 1 (g / mL), the reduction rate (%) is expressed by the following formula.
[0040]
Percentage of decrease (%) = (V 2- V 3 ) / (V 1 x (P 1 / (1 + P 1 ) x D 1 ) x 100
[0041]
　(9) Stickiness of
　pest repellent composition The pest repellent composition was subjected to a sensory test by 20 specialized panelists, and an interview survey was conducted regarding the stickiness during application to the skin. The results were evaluated based on the following evaluation point criteria. Here, it was evaluated that it was so excellent that it did not feel sticky.
Evaluation score criteria
◎: Very good
○: Excellent
△: Normal
▲: Inferior
×: Very inferior
[0042]
　[Example 2]
　SMB_SP-1 (manufactured by Nikki Catalyst Kasei Co., Ltd .: average particle diameter 12 μm, pore volume 2.9 mL / g, pore diameter 100 nm, oil absorption 370 mL / g) was used as the raw material particles, and the same as in Example 1. Was hydrophobized to prepare porous particles. To 0.5 kg of the porous particles, 10.2 kg of ethanol and 1.5 liters of DEET (manufactured by Tokyo Chemical Industry Co., Ltd.) were added and stirred in a closed container for 30 minutes to obtain a pest repellent composition. This pest repellent composition contains 12% by weight of DEET, 84% by weight of ethanol, and 4% by weight of porous particles. The physical characteristics of these samples were measured in the same manner as in Example 1.
[0043]
　[Example 3]
　Porous particles were prepared by performing a hydrophobic treatment in the same manner as in Example 1 except that particles having an average particle diameter of 10 μm, a pore volume of 1.3 mL / g, and a pore diameter of 5 nm were used as raw material particles. Then, a pest repellent composition was obtained. Physical characteristics were measured in the same manner as in Example 1. The pest repellent composition of this example contains 12% by weight of DEET, 79% by weight of ethanol, and 9% by weight of porous particles.
[0044]
　[Example 4]
　Porous particles were prepared by performing a hydrophobizing treatment in the same manner as in Example 2. To 1.0 kg of the porous particles, 6.0 kg of ethanol and 3.0 liters of Diet (manufactured by Tokyo Chemical Industry Co., Ltd.) were added, and the mixture was stirred in a closed container for 30 minutes to obtain a pest repellent composition. This pest repellent composition contains 30% by weight of DEET, 60% by weight of ethanol, and 10% by weight of porous particles. The physical characteristics of these samples were measured in the same manner as in Example 1.
[0045]
　[Comparative Example 1] To
　1.0 kg of the same raw material particles (manufactured by Nikki Catalyst Kasei Co., Ltd .: SMB LB-1500) as in Example 1, 8.5 kg of ethanol and 1.3 liters of DEET (manufactured by Tokyo Chemical Industry Co., Ltd.) are added and sealed. The mixture was stirred in a container for 30 minutes. That is, a pest repellent composition was prepared without hydrophobizing the raw material particles. The physical characteristics of these samples were measured in the same manner as in Example 1.
[0046]
　[Comparative Example 2] The
　same raw material particles as in Example 2 (manufactured by JGC Catalysts and Chemicals Co., Ltd .: SMB SP-10.5 kg, 10.2 kg of ethanol and 1.5 liters of DEET (manufactured by Tokyo Chemical Industry Co., Ltd.) are added and placed in a closed container. The mixture was stirred for 30 minutes. That is, the pest repellent composition was prepared without subjecting the raw material particles to the hydrophobic treatment. The physical properties of these samples were measured in the same manner as in Example 1.
[0047]
[table 1]

[0048]
[Table 2]

The scope of the claims
[Claim 1]
　A pest repellent composition containing a pest repellent component, porous particles in which primary particles containing silica as a component form pores and aggregated, and a solvent, and in
　the infrared absorption spectrum of the porous particles, 3750cm from 3730 -1 maximum absorbance at (I 1 and), from 1160 1260 cm -1 absorbance maximum (I 2 ratio of the) (I 1 / I 2 ) is repellent, characterized in that 0.005 or less Composition.
[Claim 2]
　The first aspect of the present invention, wherein the porous particles have a pore volume (PV) of more than 1.0 to 5.0 mL / g and an average pore diameter (PD) of 0.005 to 0.5 μm. Pest repellent composition.
[Claim 3]
　The pest repellent composition according to claim 1 or 2, wherein the porous particles have a hygroscopicity of 10% or less when allowed to stand for 24 hours under the conditions of a temperature of 80 ° C. and a relative humidity of 80%. ..
[Claim 4]
　The pest repellent composition according to any one of claims 1 to 3, wherein the pore opening ratio on the surface of the porous particles is 20 to 75%.
[Claim 5]
　Any one of claims 1 to 4, wherein the ratio (PD / VP) of the average pore diameter PD [μm] to the vapor pressure VP [Pa] of the pest repellent component at 20 ° C. is 500 or less. The pest repellent composition according to.
[Claim 6]
　The pest according to any one of claims 1 to 5, wherein the porous particles have a contact angle with respect to water of more than 90 ° and a contact angle with respect to the pest repellent component of 1 ° to 90 °. Repellent composition.
[Claim 7]
The ratio (V PS / VP ) 　of the vapor pressure V PS [Pa] of the main component of the solvent at 20 ° C. to the vapor pressure V P [Pa] of the pest repellent component at 20 ° C. is 1000 or more. The pest repellent composition according to any one of claims 1 to 6.