Emulsified products, as well as their dilutions and mixtures.

Abstract

The present invention provides emulsions with excellent emulsification stability, as well as their dilutions and mixtures. [Solution] An emulsion containing essential oil, sugar ester, and water, wherein the alcohol content relative to the essential oil is 0-5% by mass.

Description

Technical Field

[0001] The present invention relates to emulsions, as well as dilutions and mixtures thereof.

Background Art

[0002] Essential oils (oils obtained from plants. Generally have a specific aroma.) have various effects and have thus been conventionally used in various fields. For example, hinoki essential oil, a natural essential oil extracted by steam distillation from the wood part of hinoki (especially Aomori hinoki), is known to have aromatic, antibacterial, bactericidal, antifungal, insecticidal, and other properties, and attempts have been made to utilize it in various hair tonics, detergents, cosmetics, bath agents, oral care products such as toothpaste, freshness-retaining packaging for foods, plant disease control, insecticides, etc. By the way, since essential oils are hydrophobic, it is difficult to maintain a stable emulsion for a long time when they are blended into products using water as a solvent. Therefore, attempts have been made to stabilize the dispersion using alcohol. On the other hand, when an emulsion is prepared using alcohol, there is a risk that its effects, such as the aromatic odor of the essential oil, may be inhibited. Under such circumstances, Patent Document 1 discloses a composition of hinoki essential oil using polyoxyethylene sorbitan monooleate as a surfactant without using alcohol (Examples, etc.). Patent Document 1 describes that by making such a composition, a uniform and stable emulsified dispersion state is achieved.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] On the other hand, when the inventors prepared an essential oil emulsion based on the examples in Patent Document 1, it became clear that although an emulsion was indeed obtained, the essential oil and water sometimes separated over time. This separation of essential oil and water is problematic because it leads to changes in the properties of the emulsion and variations in its efficacy.

[0005] Therefore, in view of the above circumstances, the present invention aims to provide an emulsion with excellent emulsification stability, as well as its dilutions and mixtures. [Means for solving the problem]

[0006] As a result of diligent research into the above-mentioned problems, the inventors of this invention discovered that these problems could be solved by using sugar esters as surfactants, leading to the present invention. In other words, the inventors have found that the above problem can be solved by the following configuration.

[0007] (1) An emulsion containing an essential oil, a sugar ester, and water, wherein the alcohol content relative to the essential oil is 0 to 5% by mass. (2) The emulsion described in (1) above, wherein the average particle size of the essential oil is 100 to 700 nm. (3) The emulsion described in (1) above, wherein the polydispersity index of the particle size distribution of the essential oil is 0.33 or less. (4) A dilution obtained by diluting any of the emulsions described in (1) to (3) above with water. (5) A mixture of the emulsion described in any of (1) to (3) above and clay. (6) A mixture of an emulsion described in any of (1) to (3) above and a gelling agent or a superabsorbent polymer. [Effects of the Invention]

[0008] As shown below, the present invention provides emulsions with excellent emulsification stability, as well as their dilutions and mixtures. Furthermore, these exhibit excellent deodorizing, insecticidal (insect repellent), antifungal, virus inactivating, and bactericidal properties, allowing for the provision of various formulations that utilize these characteristics. [Brief explanation of the drawing]

[0009] [Figure 1] This is the particle size distribution of the emulsion in Example 1. [Figure 2] This is the particle size distribution of the emulsion in Example 2. [Figure 3] This is the particle size distribution of the emulsion in Example 3. [Figure 4] This is the particle size distribution of the emulsion in Example 4. [Modes for carrying out the invention]

[0010] The emulsions and the like of the present invention will be described below. In this specification, numerical ranges represented by "~" mean a range that includes the numbers written before and after "~" as the lower and upper limits, respectively. Furthermore, each component may be used alone or in combination of two or more. When two or more components are used in combination, the "content" of each component refers to the total content unless otherwise specified. Furthermore, the emulsion of the present invention exhibits excellent emulsification stability, deodorizing properties, insecticidal properties (insect repellent properties), mold prevention, virus inactivation properties, and bactericidal properties, which can be collectively described as "excellent effects of the present invention."

[0011] [1] Emulsion The emulsion of the present invention is an emulsion containing an essential oil, a sugar ester, and water, wherein the alcohol content relative to the essential oil is 0 to 5% by mass.

[0012] Because the emulsion of the present invention has this configuration, it is believed to solve the problems described above. The reason for this is not clear, but it is thought to be roughly as follows. In the emulsion of the present invention, fine particles of essential oil (hereinafter also referred to as "essential oil particles") are dispersed in water. Here, the sugar ester contained in the emulsion of the present invention is considered to function as a surfactant. More specifically, the hydrocarbon chain portion of the sugar ester (particularly the alkyl chain of the carboxylic acid constituting the sugar ester) is compatible with the essential oil particles, and the hydroxyl group or ester group of the sugar ester is compatible with water. Furthermore, since the chain structure and cyclic structure of the sugar ester are in equilibrium, it is considered that the sugar ester also has the function of suppressing changes in the emulsion over time through equilibrium shift. In other words, the sugar ester is considered to not only function as a surfactant but also to have the effect of enhancing the stability of the emulsion. As a result, the emulsion of the present invention is considered to exhibit extremely excellent emulsion stability.

[0013] The following describes each component contained in the emulsion of the present invention.

[0014] [Essential oil] The essential oil contained in the emulsion of the present invention is an oil obtained from plants or trees. Examples of essential oils include hinoki oil, cypress oil, camphor tree oil, fragrant osmanthus oil, dwarf pine oil, katsura tree oil, sugi oil, fir oil, asunaro oil, mizumezakura oil, sansho oil, mock orange oil, eucalyptus oil, anise oil, amyriss oil, angelica oil, benzoin oil, imortel oil, ylang-ylang oil, elemi oil, oregano oil, orange oil, chamomile oil, cajuput oil, cardamom oil, galbanum oil, camphor oil, caraway oil, carrot seed oil, guaiacwood oil, cumin oil, clarissa oil, grapefruit oil, clove oil, coriander oil, cypress oil, sandalwood oil, santolina oil, cedarwood oil, citronella oil, cinnamon oil, jasmine oil, juniper oil, ginger oil, star anise oil, spike lavender oil, spearmint oil, sage oil, geranium oil, celery oil, thyme oil, tagetes oil, tarragon oil, tangelo oil, tea tree oil, dill oil, turpentine oil, nutmeg oil, nearuri oil, frankincense oil, neroli oil, violet oil, pine oil, basil oil, parsley oil, birch oil, patchouli oil, vervain oil, rose oil, palmarosa oil, hyssop oil, pimento oil, fir oil, fennel oil, ptychoglenn oil, black pepper oil, vetiver oil, peppermint oil, bergamot oil, bodaiju flower oil, marjoram oil, myrtle oil, mandarin oil, melissa oil, myrrh oil, yarrow oil, eucalyptus oil, lime oil, lavandin oil, lavender oil, litsea cubeba oil, lemon oil, lemongrass oil, rosewood oil, rosemary oil, laurel oil, yuzu oil, perilla oil, etc. Among these, hinoki oil is preferred because the effects of the present invention are more excellent.

[0015] 〔Content〕 In the emulsion of the present invention, the content of the essential oil is preferably 0.08 to 20% by mass, more preferably 0.05 to 10% by mass, and even more preferably 0.1 to 5% by mass because the effects of the present invention are more excellent.

[0016] [Sugar ester] The sugar ester contained in the emulsion of the present invention is an ester (carboxylic acid ester) of sugar (saccharides), and more specifically, it is an ester obtained by reacting at least one hydroxyl group of sugar with a carboxylic acid or its derivative (hereinafter also referred to as "carboxylic acids").

[0017] 〔Sugar〕 The above sugar is not particularly limited, and examples include monosaccharides, disaccharides, oligosaccharides, etc. Specific examples include refined sugar, granulated sugar, powdered sugar, liquid sugar, glucose, fructose, sorbitol, sucrose, maltose, lactose, honey, enzyme saccharified starch syrup, isomerized liquid sugar, sucrose-bound starch syrup, reduced saccharified starch syrup, oligosaccharides, trehalose, xylose, maltitol, erythritol, mannitol, fructooligosaccharides, soy oligosaccharides, galactooligosaccharides, lactulose oligosaccharides, raffinose, lactulose, palatinose oligosaccharides, etc. Among them, sucrose is preferred because the effects of the present invention are more excellent.

[0018] 〔Carboxylic acids〕 The above carboxylic acids are not particularly limited, and specific examples include fatty acids (saturated fatty acids, unsaturated fatty acids), aromatic carboxylic acids, dicarboxylic acids, tricarboxylic acids, carboxylic acid derivatives (for example, acid anhydrides, acid halides), etc. Among them, fatty acids are preferred because the effects of the present invention are more excellent. From the reason that the effects of the present invention are more excellent, the above fatty acid is preferably a saturated fatty acid having 1 to 30 carbon atoms, more preferably a saturated fatty acid having 10 to 20 carbon atoms, and even more preferably stearic acid.

[0019] 〔Preferred embodiment〕 The above sugar ester may be a monoester (in which one hydroxyl group of sugar becomes an ester), a polyester (in which two or more hydroxyl groups of sugar become an ester), or a mixture thereof. However, from the reason that the effects of the present invention are more excellent, the above mixture is preferred. When the sugar ester is the above mixture, the proportion of polyester to the total of the monoester and polyester is preferably 30% by mass or more, more preferably 50% by mass or more, and even more preferably 75% by mass or more, for reasons that the effects of the present invention are superior.

[0020] The above sugar ester is preferably an ester of sucrose and a fatty acid, and more preferably an ester of sucrose and stearic acid, for reasons that the effects of the present invention are superior.

[0021] [HLB value] The HLB value of the above sugar ester is not particularly limited, but for reasons of superior effects of the present invention, it is preferably 15 or less, more preferably 10 or less, even more preferably 8 or less, and particularly preferably 6 or less. The lower limit of the above HLB value is not particularly limited, but for reasons of superior effects of the present invention, it is preferably 1 or more, and more preferably 3 or more. The HLB value is calculated using Griffin's formula. In the Griffin calculation formula, the HLB value is calculated according to the following formula, using the value of S (saponification value of the ester) and the value of N (neutralization value of the fatty acids constituting the ester). An HLB value closer to 20 indicates a hydrophilic nature, while a value closer to 0 indicates a lipophilic nature. It means... HLB value = 20(1-S / N)

[0022] [Content] In the emulsion of the present invention, the sugar ester content is preferably 0.1 to 100% by mass, more preferably 1 to 50% by mass, even more preferably 5 to 20% by mass, and particularly preferably 10 to 20% by mass, relative to the essential oil, for reasons that the effects of the present invention are superior.

[0023] [water] In the emulsion of the present invention, the water content is preferably 50 to 99.99% by mass, more preferably 70 to 99.9% by mass, and even more preferably 90 to 99% by mass, for reasons that the effects of the present invention are superior.

[0024] [alcohol] In the emulsion of the present invention, the alcohol content relative to the essential oil is 0 to 5% by mass. The above content is preferably 3% by mass or less, more preferably 1% by mass or less, even more preferably 0.1% by mass or less, particularly preferably 0.01% by mass or less, and most preferably 0% by mass (i.e., no alcohol content) for reasons that the effects of the present invention are superior.

[0025] Note that the above alcohols do not include esters (for example, the sugar esters mentioned above).

[0026] [Other ingredients] The emulsion of the present invention may contain components other than those described above (other components). Other components include, for example, surfactants other than sugar esters, organic solvents other than alcohols, and so on.

[0027] [Content] In the emulsion of the present invention, the content of other components is preferably 30% by mass or less, more preferably 10% by mass or less, even more preferably 5% by mass or less, and particularly preferably 1% by mass or less, for reasons that the effects of the present invention are superior.

[0028] [Preparation method] The method for preparing the emulsion of the present invention is not particularly limited and includes methods such as mixing and stirring the above-mentioned components.

[0029] [Average particle size and polydispersity index] As described above, in the emulsion of the present invention, essential oil particles are dispersed in water. The average particle size of the essential oil particles is preferably 100 to 700 nm, more preferably 200 to 600 nm, even more preferably 300 to 550 nm, and particularly preferably 350 to 400 nm, for reasons that the effects of the present invention are superior.

[0030] Furthermore, the polydispersity index of the essential oil particles is preferably 0.33 or less, more preferably 0.30 or less, even more preferably 0.25 or less, and particularly preferably 0.20 or less, for reasons that the effects of the present invention are superior. The lower limit of the polydispersity index is not particularly limited, but is usually 0.01 or higher.

[0031] The methods for measuring the average particle size and polydispersity index described above are as shown in the examples below.

[0032] [2] Dilution The dilution of the present invention is obtained by diluting the emulsion of the present invention described above with water. The dilution of the present invention is useful, for example, when applying the emulsion of the present invention described above to a spray container or the like. The dilution ratio is not particularly limited, but it is preferably 2 to 1000 times, and more preferably 5 to 100 times.

[0033] [3] Mixture (clay type) The mixture (clay type) of the present invention is a mixture of the emulsion of the present invention described above and clay. By creating such a mixture, it becomes possible to mold (granulate, etc.), making it easier to handle and useful, for example, as a deodorizer for compost. Conventional known clays can be used as the above-mentioned clay. Specific examples of clays include bentonite, zeolite, and talc. For optimal results of the present invention, the amount of emulsion mixed with clay is preferably such that the moisture content of the emulsion relative to the dry clay (powder) is 15-25% by mass.

[0034] [4] Mixture (gel type) The mixture (gel type) of the present invention is a mixture of the emulsion of the present invention described above and a gelling agent or a water-absorbing polymer. By creating such a mixture, it becomes gel-like, making it easy to handle and useful for applications such as household deodorizers (e.g., refrigerator deodorizers) and insect repellents. Conventional known gelling agents and superabsorbent polymers can be used as the above-mentioned gelling agents and superabsorbent polymers.

[0035] [5]Usage The emulsions, dilutions, and mixtures of the present invention are particularly useful as deodorants, fragrances, insect repellents, fungicides, insecticides, cleaning agents, cosmetics, bath additives, repellents, freshness preservatives for vegetables, pharmaceuticals, and the like. [Examples]

[0036] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0037] [Preparation of emulsions] Each emulsion was prepared as follows.

[0038] [Example 1] An emulsion was obtained by mixing 10 parts by mass of Aomori-produced cypress essential oil, 1 part by mass of sucrose fatty acid ester (fatty acid: stearic acid, monoester: 10% by mass, polyester: 90% by mass, HLB value: 2) as a surfactant, and 89 parts by mass of water using a stirrer.

[0039] [Example 2] An emulsion was obtained in the same manner as in Example 1, except that a sucrose fatty acid ester (fatty acid: stearic acid, monoester: 30% by mass, polyester: 70% by mass, HLB value: 5) was used as the surfactant.

[0040] [Example 3] An emulsion was obtained in the same manner as in Example 1, except that a sucrose fatty acid ester (fatty acid: stearic acid, monoester: 40% by mass, polyester: 60% by mass, HLB value: 7) was used as the surfactant.

[0041] [Example 4] An emulsion was obtained in the same manner as in Example 1, except that a sucrose fatty acid ester (fatty acid: stearic acid, monoester: 50% by mass, polyester: 50% by mass, HLB value: 9) was used as the surfactant.

[0042] [Example 5] An emulsion was obtained in the same manner as in Example 1, except that a sucrose fatty acid ester (fatty acid: stearic acid, monoester: 55% by mass, polyester: 45% by mass, HLB value: 11) was used as the surfactant.

[0043] [Comparative Example 1] An emulsion was obtained in the same manner as in Example 1, except that polyoxyethylene sorbitan monooleate was used as the surfactant.

[0044] [Average particle size and polydispersity index] For each emulsion immediately after preparation, the average particle size (cumulant method) and polydispersity index (cumulant method) of essential oil particles were measured by dynamic light scattering (measurement temperature 20°C). The results are shown in Table 1. In addition, the particle size distribution (histogram method) of Examples 1 to 4 immediately after preparation is shown in Figures 1 to 4.

[0045] [Emulsification stability] The resulting emulsion was allowed to stand, and separation was observed. The emulsion stability was then evaluated according to the following criteria: △ or higher is preferable, ○ or higher is more preferable, and ◎ is even preferable. The results are shown in Table 1. ◎: No separation observed for more than one year. ○: The number of days until separation was observed was between one month and one year. △: The number of days until separation was observed was 5 days or more but less than 1 month. ×: The number of days until separation was observed was less than 5 days.

[0046] [Table 1]

[0047] As can be seen from Table 1, Examples 1-5, which used sugar esters as surfactants, showed excellent emulsification stability. In particular, Examples 1-4, in which the average particle size of essential oil particles was 300-550 nm, showed even better emulsification stability.

[0048] On the other hand, Comparative Example 1, which used surfactants other than sugar esters, exhibited insufficient emulsification stability.

[0049] [Deodorizer] The emulsions of Examples 1-5 (hereinafter also simply referred to as "Examples") were each diluted 10 times with water and placed in spray bottles. Then, a deodorizing test (sprayed on kimchi) was performed on each diluted emulsion (deodorizer), and excellent deodorizing effects were confirmed in all cases.

[0050] [Test Method] The specific testing method for the deodorization test is as follows: 40g of commercially available kimchi, sprayed with each deodorizer, was sealed. This was placed in a 10L gas bag, 9L of N2 gas was injected, and the odor intensity was measured by olfactory detection at predetermined intervals using a 6-level odor intensity scale.

[0051] [Table 2]

[0052] [Test Results] The specific test results for the deodorant obtained from the emulsion of Example 2 are shown below.

[0053] [Table 3]

[0054] [Clay type] Each emulsion from the examples was added to clay (in a dry powder state) and thoroughly mixed using a machine. Then, granulation was performed using a granulator (extrusion granulation under pressure). Next, the mixtures were dried twice in a dryer (120°C). In this way, each mixture (clay type) was obtained. When each of the obtained mixtures was used in a deodorization test (spread on compost), excellent deodorizing effects were confirmed in all cases. Bentonite, zeolite, and talc were used as clay. The emulsion was mixed with the clay so that its moisture content relative to the dry clay (powder) was approximately 22.5% by mass.

[0055] [Gel type] A gelling agent, a water-synchronizing agent, and NaCl were added to pure water and stirred until dissolved. The aqueous solution was heated while stirring. After reaching a certain temperature, it was allowed to cool naturally. Once the temperature of the aqueous solution had cooled to the specified temperature, the emulsions from the examples were added and stirred. Then, it was allowed to stand until it solidified. In this way, each mixture (gel type) was obtained. Deodorization tests (placed in refrigerators, toilets, etc.) and cockroach repellent tests were conducted using each of the obtained mixtures, and excellent deodorizing and repellent effects were confirmed in both cases.

[0056] The specific details of the repellency test for the mixture (gel type) using the emulsified solution of Example 2 are shown below.

[0057] [Table 4] JPEG2026085350000005.jpg27124

Claims

1. An emulsion containing an essential oil, a sugar ester, and water, wherein the alcohol content relative to the essential oil is 0 to 5% by mass.

2. The emulsion according to claim 1, wherein the average particle size of the essential oil is 100 to 700 nm.

3. The emulsion according to claim 1, wherein the polydispersity index of the particle size distribution of the essential oil is 0.33 or less.

4. A dilution obtained by diluting the emulsion according to any one of claims 1 to 3 with water.

5. A mixture of an emulsion and clay according to any one of claims 1 to 3.

6. A mixture of an emulsion according to any one of claims 1 to 3 and a gelling agent or a water-absorbing polymer.

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