Water sealing capsule and manufacturing method thereof

Abstract

The present invention addresses the problem of providing a water-sealing seamless capsule technique capable of encapsulating and holding water in a content liquid in a capsule over a long period of time. In a water-sealing capsule provided with a water-containing core containing water and a sealing layer disposed on the outside of the water-containing core, the sealing layer is formed from a lipophilic composition having a specific gravity set to a specific range, and the film thickness of the sealing layer is set to a holding range that is equal to or greater than a certain film thickness. Thus, moisture in the water-containing core can be encapsulated and held in the capsule for a long period of time.

Description

Technical Field

[0001] The present invention relates to a water-sealing capsule comprising a water-containing core containing water and a sealing layer arranged outside the water-containing core, and a method for producing the same. Background Art

[0002] In the past, as a water-sealing capsule, there is known a water-sealing capsule with excellent water evaporation resistance, which includes a water-containing core containing water, an inner layer arranged on the outside of the water-containing core, and an outer layer arranged on the outside of the inner layer, the inner layer is composed of a lipophilic material, and the outer layer is composed of a hydrophilic material in which lipophilic particles or water-insoluble particles are dispersed (Patent Document 1).

[0003] In addition, regarding the filter element for use in tobacco articles, there is known a filter element, which has at least one filter body, and a capsule having a core material containing a liquid medium and a water vapor impermeable polymer shell, wherein the liquid medium of the core material contains at least one surfactant (Patent Document 2). In addition, a method for manufacturing a destructible raw capsule useful for assembly into a tobacco product is proposed (Patent Document 3).

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent No. 6250211

[0007] Patent Document 2: Japanese Patent Application No. 2020-527953

[0008] Patent Document 3: Japanese Patent Application No. 2011-512122 Summary of the invention

[0009] Problems to be solved by the invention

[0010] As the content liquid that can be formulated by soft capsule, oil, oil-soluble substances or emulsions (lipophilic + hydrophilic) are well known. On the other hand, even if water or a content liquid with water as the main component can be encapsulated, the water will evaporate quickly through the capsule membrane after encapsulation, and the moisture of the content liquid cannot be maintained for a long time. Therefore, as far as the applicant knows, the current situation is that capsule products encapsulated with water or aqueous solutions have not yet been circulated on the market. Therefore, the subject of the present invention is to provide a water-resistant water-sealed seamless capsule technology that can encapsulate and maintain the moisture of the content liquid in the capsule for a long time.

[0011] Means for solving problems

[0012] In order to solve the above-mentioned problems, the inventors of the present application conducted in-depth research and found that by preparing a sealing layer formed by a lipophilic composition with a specific gravity set to a specific range in a water-sealing capsule having a water-containing core and a sealing layer arranged on the outside of the water-containing core, and setting a film thickness of the sealing layer above a certain thickness as a retention range, the moisture in the water-containing core can be encapsulated and retained in the capsule for a long time. In addition, by making it contain a viscous additive that imparts viscosity to the water in the water-containing core, the preparation properties of the capsule can be improved, thereby completing the present invention.

[0013] That is, the present invention is as defined by the following invention specific matters.

[0014] [1] A water-sealing capsule, characterized in that it comprises a water-containing core containing water and a sealing layer arranged on the outside of the water-containing core, the sealing layer being formed of a lipophilic composition having a specific gravity of 0.79 to 1.05, and the thinnest part of the sealing layer being 80 μm or more.

[0015] [2] The water-sealing capsule according to [1] above, wherein the water-containing core contains a viscosity-enhancing agent that imparts viscosity to water.

[0016] [3] The water-sealing capsule according to [1] above, wherein the lipophilic composition contains a specific gravity adjuster that makes the specific gravity of the lipophilic composition 0.79 to 1.05.

[0017] [4] The water-sealing capsule according to [1] above, wherein the melting point of the lipophilic composition is 16° C. or higher.

[0018] [5] The water-sealing capsule according to [1] above, wherein the lipophilic composition comprises a solid fat having a melting point of 30 to 70°C.

[0019] [6] The water-sealing capsule according to [1] above, wherein the lipophilic composition comprises a liquid fat having a melting point lower than 20°C.

[0020] [7] The water-sealing capsule as described in [1] above is characterized in that a membrane layer is further provided on the outer side of the sealing layer.

[0021] [8] The water-sealing capsule according to [7] above, wherein the moisture content of the membrane layer is greater than 20%.

[0022] [9] The water-sealing capsule as described in [7] above is characterized in that the moisture content of the membrane layer is less than 20%.

[0023] In addition, the present invention is defined by the following invention specific matters.

[0024]

[10] The method for manufacturing a water-sealing capsule described in any one of [1] to [9] above is characterized in that a triple coaxial nozzle is used to spray a water-containing core from an inner nozzle, a sealing layer from a middle nozzle, and a membrane layer from an outer nozzle, thereby forming a three-layer droplet, and the three-layer droplet is brought into contact with a cooling solvent to form a water-sealing precapsule.

[0025]

[11] The manufacturing method according to

[10] above is characterized in that the membrane layer is peeled off and removed before drying the water-sealed pre-capsule, thereby forming two layers: a water-containing core containing water and a sealing layer arranged outside the water-containing core.

[0026]

[12] The method for producing a water-sealing capsule as described in

[10] above is characterized in that the three-layer water-sealing raw capsule is prepared in a manner that does not allow the water-sealing pre-capsule to dry.

[0027]

[13] The method for manufacturing a water-sealing capsule as described in

[10] above is characterized in that a three-layer water-sealing dry capsule is prepared by further undergoing a water-sealing pre-capsule drying step.

[0028] Effects of the Invention

[0029] According to the present invention, a three-layer water-sealed seamless capsule and a double-layer water-sealed seamless capsule can be provided, wherein the water-sealed seamless capsule has a small change in water-sealing rate over time when placed in the open at room temperature, can encapsulate and retain the moisture of the content liquid (water-containing core) in the capsule for a long time, and has excellent water resistance. Moreover, the physical properties of the sealing layer can be set according to the purpose of the water-sealed capsule. In addition, regarding the physical properties of the sealing layer arranged on the outside of the water-containing core, it can be set to be hard or soft by the oily substance constituting it. For example, in the case of setting the sealing layer to be softer, a double-layer capsule design can be used to produce a water-sealed raw capsule that can be easily crushed with fingers and used, and can be used for cosmetics, quasi-pharmaceuticals, etc. DETAILED DESCRIPTION

[0030] The water-sealing capsule of the present invention is not particularly limited as long as it comprises a water-containing core containing water and a sealing layer arranged on the outside of the water-containing core, and the aforementioned sealing layer is formed of a lipophilic composition with a specific gravity of 0.79 to 1.05, and the thinnest part of the film thickness of the sealing layer is 80 μm or more. Preferred examples include double-layer water-sealing capsules and triple-layer water-sealing capsules, but it may also be a multi-layer water-sealing capsule with 4 or more layers.

[0031] The water-containing core is not particularly limited as long as it contains water. The core may consist of water alone, but preferably contains a viscosity-imparting agent that imparts viscosity to water. The core may contain other various active ingredients and various additives.

[0032] Examples of the viscosity-enhancing agent include alginates such as alginic acid and sodium alginate, alginates such as propylene glycol alginate, methylcellulose, ethylcellulose, hydroxypropyl methylcellulose, hydroxypropyl cellulose, celluloses such as carboxymethylcellulose, gelatin, carrageenan, agar, starch, modified starch, dextran, dextrin, pullulan, glucomannan, gum arabic, furcellan, tragacanth gum, guar gum, locust bean gum, gellan gum, xanthan gum, polyvinyl pyrrolidone, polyvinyl alcohol, glucosamine, Eucheuma, soybean water-soluble polysaccharides, welan gum, cassia gum, Agrobacterium succinoglycan, succinoglycan), guar gum hydrolysate, ghatti gum, arabinogalactan, curdlan, karaya gum, tamarind gum, psyllium gum, tara gum, flaxseed gum, konjac flour (corm), hydroxypropyl guar gum, pectin, etc.

[0033] In the above-mentioned sealing layer, as the oily substance constituting the lipophilic composition, first, there can be mentioned an oily substance having a melting point of 20° C. or higher (hereinafter referred to as “solid fats and oils”), specifically, hydrogenated oils (substances having a higher melting point by hydrogenating liquid animal and vegetable fats and oils), partially hydrogenated oils (hydrogenated oils obtained by hydrogenating only a part of liquid animal and vegetable fats and oils or a mixture of unhydrogenated fats and oils and hydrogenated oils), and waxes. Specific examples of solid fats and oils include hydrogenated castor oil, hydrogenated soybean oil, hydrogenated rapeseed oil, hydrogenated coconut oil, cocoa butter, butter, hydrogenated palm kernel oil, beef tallow, hydrogenated beef tallow, lard, hydrogenated lard, beeswax, candelilla wax, rice bran wax, carnauba wax, wood wax (Japan wax, lacquer wax), etc., or mixtures thereof.

[0034] As the oily substance constituting the above-mentioned lipophilic composition, secondly, there can be mentioned liquid oily substances having a melting point below 20°C (hereinafter referred to as "liquid oils and fats"), specifically, safflower oil, linseed oil, sesame oil, olive oil, soybean oil, mustard oil, rapeseed oil, corn oil, castor oil, evening primrose oil, palm kernel oil, jojoba oil, cottonseed oil, coconut oil, peanut oil, EPA, DHA, DPA, squalane, shark liver oil, cod liver oil and other animal and plant oils, medium-chain fatty acid triglycerides (MCT), liquid paraffin, etc.

[0035] As the oily substance constituting the above-mentioned lipophilic composition, there can also be mentioned an oily substance with high lipophilicity (for example, an oily substance with HLB less than 7, an oily substance with HLB less than 10) among surfactants such as glycerol fatty acid esters, sucrose fatty acid esters, and fatty acid acyl esters. In this case, among the above-mentioned surfactants, an oily substance that is solid at 20° C. can be used as a solid fat, and an oily substance that is liquid at a temperature below 20° C. can be used as a liquid fat. As for the lipophilic composition that can be used in the present invention, one or more kinds of solid fats and liquid fats can be mixed and used appropriately. In addition, as commercially available products, "GELUCIRE" series manufactured and sold by Gattefosse, Nissin MCT oil, Kao "Excel" series, Kao "Econa" series, Kao "Emanon" series, Kao "Rheodol" series, etc. can also be used.

[0036] In addition, as the oily substance constituting the lipophilic composition, various functional ingredients of oiliness can also be used (they are ingredients having various functions such as nutritional function, function of fragrance, function of pigment, and are oily ingredients). As the oily nutritional functional ingredients that can be used in the present invention, for example, oleic acid, linoleic acid, linolenic acid, arachidonic acid, eicosapentaenoic acid, docosahexaenoic acid, docosapentaenoic acid and other omega fatty acids, oily substances such as prostaglandins, vitamin A, vitamin E, vitamin D, vitamin K and other oil-soluble vitamins, and oils and fats containing them can be cited. As the oily component having the function of fragrance, orange oil, lemon oil, perilla oil, ambrette seed oil, iris root oil, ylang-ylang oil, mustard oil, caraway oil, carrot seed oil, grapefruit oil, ginger oil, hop oil, myrtle oil, rose oil, rosemary oil and other natural essential oils, eugenol, ethyl caprylate, geraniol, menthol, citral, citronellal, borneol and other synthetic or natural fragrances can be cited. Examples of the oily component having a pigment function include oily colorants such as annatto, carotene, and oleoresin, etc. It goes without saying that these may be used alone or in combination of two or more.

[0037] The lipophilic composition may contain an oil-insoluble component. As the oil-insoluble component, any component that can be mixed with the oily component can be used. As the oil-insoluble component that can be mixed with the oily component, for example, inorganic powders such as titanium dioxide, calcium carbonate, magnesium carbonate, magnesium oxide, calcium stearate, magnesium stearate, (fine-particle) silicon dioxide, and aluminum oxide can be used.

[0038] In order to make the specific gravity of the above-mentioned lipophilic composition within the specified range, a specific gravity adjusting agent can be used. The specific gravity adjusting agent is a substance that can be dissolved or mixed with the lipophilic composition and has a specific gravity different from the specific gravity of the lipophilic composition before adding the specific gravity adjusting agent. As a specific gravity adjusting agent, oily substances with a specific gravity of more than 1 such as SAIB (Sucrose Acetate Isobutylate: sucrose fatty acid ester), wood rosin glycerol ester, and sucrose octaacetate can be preferably used. In addition, inorganic powders such as titanium dioxide, calcium carbonate, magnesium carbonate, magnesium oxide, calcium stearate, magnesium stearate, (microparticle) silicon dioxide, and aluminum oxide can also be used as specific gravity adjusting agents, as long as the specific gravity can be adjusted by mixing with the lipophilic composition before addition. In addition, animal and vegetable oils, synthetic oils, ester oils, mineral oils, etc. allowed in the purpose of use of the present invention can also be used as specific gravity adjusting agents, as long as the specific gravity can be adjusted by adding them to the lipophilic composition before addition.

[0039] Preferred examples of the specific gravity of the sealing layer in the present invention include 0.79 to 1.05, 0.79 to 1.03, 0.79 to 1.0, 0.795 to 1.05, 0.795 to 1.03, 0.795 to 1.0, 0.8 to 1.05, 0.8 to 1.03, 0.8 to 1.0, 0.83 to 1.05, 0.83 to 1.03, 0.83 to 1.0, 0.85 to 1.05, 0.85 to 1.03, 0.85 to 1.0, and particularly 0.80 to 1.0. It should be noted that, as the sealing layer, it was confirmed that a low specific gravity lipophilic composition [for example, a mixture of the above-mentioned squalane and hydrogenated oil, sealing layer specific gravity: 0.795] and a high specific gravity lipophilic composition [for example, a mixture of the above-mentioned SAIB and hydrogenated oil, sealing layer specific gravity: 1.03] can be used to formulate a water-sealing capsule.

[0040] Regarding the film thickness of the above-mentioned sealing layer, what is important is the thickness of the thinnest part (thinnest part film thickness). As long as it is kept above the minimum limit, for example, above 80μm, preferably above 90μm, above 100μm, above 110μm, above 120μm, above 150μm, above 180μm, above 210μm, above 240μm, above 270μm, above 300μm, above 350μm, above 400μm, above 450μm, above 500μm, the film thickness may also have deviations.

[0041] A membrane layer may be further provided on the outside of the above-mentioned sealing layer to form a three-layer water-sealing capsule. As the membrane layer, it is a layer of the membrane commonly used as a seamless capsule, for example, a membrane layer containing gelatin, casein, zein, pectin and its derivatives, alginic acid or its salts, agar, gellan gum, tragacanth gum, guar gum, locust bean gum, carrageenan (carrageenan), tamarind gum, mannan, hemilose, starch, chitosan, etc. as a matrix. In addition, in the above-mentioned membrane layer, in addition to the matrix, plasticizers such as glycerol, sorbitol, propylene glycol, polyethylene glycol, pH regulators such as sodium phosphate, chelating agents such as trisodium citrate and sodium metaphosphate, gelling promoters such as calcium lactate and potassium chloride, surfactants such as polyglycerol fatty acid esters and lecithin, sweeteners, spices, preservatives, colorants, etc. may also be included. In addition, the film layer may also contain additives such as natural pigments, synthetic pigments, various sweeteners, preservatives, water activity reducers, pH adjusters, etc. The three-layer water-sealed capsules may also be classified into dry capsules and raw capsules according to the moisture content of the film layer.

[0042] The coating liquid used for the coating layer preferably has a viscosity of 300 mPa·s or less at 85° C. as measured by a C-type viscometer (VISCOMETER TVC-7 manufactured by Toki Sangyo Co., Ltd.) using rotor No. 1 (upper limit 500 mPa·s).

[0043] The method for manufacturing the water-sealed capsule of the present invention is not particularly limited as long as a triple coaxial nozzle is used, the water-containing core is ejected from the inner nozzle, the sealing layer is ejected from the middle nozzle, and the membrane layer is ejected from the outer nozzle to form a three-layer droplet, and the three-layer droplet is brought into contact with a cooling solvent, for example, which has been set to 0 to 25° C. to form a water-sealed pre-capsule. Examples of the cooling solvent include cooling oils such as MCT composed of fatty acids such as capric acid and caprylic acid, liquid paraffin, sunflower oil, safflower oil and other vegetable oils, or mixtures thereof, and low-temperature gases such as air, helium, nitrogen, and argon.

[0044] When the membrane layer is peeled off and removed before the water-sealed pre-capsule is dried, a double-layer water-sealed capsule (which consists of a water-containing core containing water and a sealing layer arranged on the outside of the water-containing core) can be manufactured. Regarding peeling off and removing the membrane layer before the water-sealed pre-capsule is dried, since the membrane layer is in a soft state, it can be easily peeled off using a simple tool such as fingers or a medicine spoon.

[0045] In the case where the water-sealing capsule of the present invention is a double-layer water-sealing capsule, it can be roughly divided into solid capsules and raw capsules according to the hardness of the sealing layer. Capsules with hard sealing layer can be temporarily classified as solid capsules, and capsules with soft sealing layer can be classified as raw capsules, but the dividing line between the physical property differences between the two cannot be clearly defined. Therefore, the hardness in each sealing layer formula is measured again using the rheometer to compare its maximum load. Therefore, in the present invention, for convenience, the capsule formed by the sealing layer with a maximum load of less than 5kg when the adapter is pressed to 3mm by the rheometer is classified as a double-layer water-sealing raw capsule (double-layer raw capsule), and the capsule formed by the sealing layer with a maximum load greater than 5kg is classified as a double-layer water-sealing solid capsule (double-layer solid capsule).

[0046] [Measurement method]

[0047] 150 g of the sealing layer was prepared in a 200 mL glass beaker, dissolved in a water bath at 60°C (75°C when hydrogenated oil e was included), and stirred thoroughly. 50 g of the solution was placed in a plastic polyethylene bottle, cooled under refrigeration conditions for more than 3 hours, solidified, and then allowed to stand until it returned to room temperature. The maximum load when the center of the polyethylene bottle was pressed to 3 mm with an adapter was measured using a rheometer.

[0048] [Equipment used for measurement]

[0049] SUN RHEO METER CR-3000EX-L (Sun Scientific Co.,Ltd.)

[0050] Mode: MODE1(Depth) Adapter: No.1φ10mm

[0051] REAL / HOLD: HOLD Entry distance: 3.0mm

[0052] Compression / tension: PRESS Stage moving speed: 20.0mm / min

[0053] Load cell maximum stress: 200N

[0054] Then, in order to prepare a double-layer solid capsule, as an example of the lipophilic composition of the sealing layer, a solid fat, or a solid fat and a liquid fat can be used, and the melting point (measured value) of the sealing layer is, for example, 37°C or more, and the specific gravity of the sealing layer is, for example, 0.82 to 1.05. On the other hand, in order to prepare a double-layer raw capsule, as an example of the lipophilic composition of the sealing layer, a mixed fat of a solid fat and a liquid fat can be used, and the melting point (measured value) of the sealing layer is, for example, 16 to 36.8°C, and the specific gravity of the sealing layer is, for example, 0.79 or more and less than 0.82. In addition, the double-layer raw capsule usually becomes an easily disintegrating capsule. It should be noted that it can be seen that the melting point of the sealing layer, which is a mixed fat of a solid fat and a liquid fat, does not show a double peak of the melting point of the solid fat and the melting point of the liquid fat, but shows almost a single peak.

[0055] The melting point was measured using a differential scanning calorimeter "DSC7020" (manufactured by Hitachi High-Tech Science Corporation). The measurement start temperature was 0°C, the temperature was increased at 5°C / min, and the endothermic peak was taken as the measured value of the melting point.

[0056] The melting point of the oily substance constituting the lipophilic composition is not particularly limited, but in the case where the water-sealing capsule is a double-layer capsule, it can be roughly divided into solid capsules or raw capsules according to the properties of the lipophilic composition. That is, in the case of a double-layer solid capsule, the lipophilic composition has a melting point of 20°C or more, preferably 30°C or more, and preferably 100°C or less, preferably 80°C or less, and more preferably 70°C or less. Among them, a lipophilic composition with a melting point of 30°C to 70°C can be preferably exemplified. The lipophilic composition can also be appropriately adjusted by mixing a plurality of oily substances such as hydrogenated oils with different melting points, or adding liquid animal and vegetable oils. On the other hand, in the case where the water-sealing capsule is in the form of a raw capsule, as an example, a mixed fat of the above-mentioned solid fat and a liquid fat with a melting point below 20°C can be used. For example, in the case of a water-sealing capsule in which the melting point of the mixed fat in the sealing layer is 16°C, even if it is liquid at room temperature, it remains in a semi-raw state under refrigerated conditions. If it is envisaged that it will circulate and use under refrigerated conditions, it can also be understood as a double-layer raw capsule.

[0057] On the other hand, in the case of a three-layer water-sealed capsule, it can be roughly divided into a raw capsule or a dry capsule mainly according to the properties of the membrane. In the case of a three-layer water-sealed raw capsule (three-layer raw capsule), the water-containing core is sprayed from the inner nozzle, the sealing layer is sprayed from the middle nozzle, and the membrane layer is sprayed from the outer nozzle to form three-layer droplets, and the three-layer droplets are contacted with a cooling solvent. The important feature of the water-sealed pre-capsule is that it is prepared as a three-layer raw capsule without going through a membrane drying process. The above-mentioned "drying process without membrane" (process) refers to the production of three-layer water-sealed capsules without using known capsule drying means such as spray drying, freeze drying, air blast drying, vacuum drying, static drying, vacuum vibration drying, etc., but for the sake of convenience, it may also include the case where the above drying process (drying stopping process) is stopped before the water content ratio (water content) of the membrane of the water-sealed pre-capsule becomes, for example, less than 20%, less than 25%, less than 30%, less than 45%, less than 70%, less than 90%. The water content of the membrane of the three-layer raw capsule can be 20% or more, preferably 25% or more, more preferably 30% or more, more preferably 45% or more, further preferably 70% or more, and further more preferably 90% or more.

[0058] Each film of the three-layer raw capsule without the film drying step is characterized by being soft. The moisture content of the film can be measured using, for example, an infrared moisture meter FD-720 (manufactured by Kett Electric Laboratory Co. Ltd.) under the conditions of 1 g of film / 105°C / 15 minutes.

[0059] In other words, the three-layer raw capsule can be produced by a method comprising the following steps (a) to (c), and can be stored.

[0060] Step (a), using a triple coaxial nozzle, spraying the water-containing core from the inner nozzle, spraying the sealing layer from the middle nozzle, and spraying the film layer from the outer nozzle, thereby forming three layers of droplets;

[0061] Step (b), contacting the three-layer droplets with a cooling solvent to form a water-sealed pre-capsule;

[0062] Step (c), immersing the water-sealed pre-capsule in a capsule preservation solution;

[0063] It should be noted that, for the above three-layer water-sealing capsule, in order to remove the cooling solvent adhering to the surroundings, it can also be washed with a lotion or running water as needed.

[0064] As the capsule preservation solution, an aqueous solvent containing at least one water selected from tap water, well water, distilled water, purified water, ion exchange water, ultrapure water, deep sea water, mineral water, etc. can be cited. However, since the water content of the membrane is high, for example, in the case of assuming cosmetic applications, in order to prevent the membrane from decaying, a preservative such as phenoxyethanol or an antibacterial agent such as 1,3-butylene glycol can be added to the membrane, the preservation solution, etc. The three-layer raw capsule obtained in this way can also be immersed in the preservation solution and provided for transportation. Even during storage and transportation, the water and water-soluble components contained in the capsule can be encapsulated and maintained in the capsule in the state of raw capsule for a long time, which is excellent. Therefore, as an example of the use of the three-layer raw capsule, an application in the form of a product in which water is mixed and dispersed can be cited. Its fields can be conceived to cover a wide range of fields such as food, pharmaceuticals, quasi-drugs, cosmetic compositions such as cosmetics, skin external preparations, beverages, pet food, and hobby products.

[0065] On the other hand, the capsule prepared by drying the water-sealed pre-capsule by using a known capsule drying method such as spray drying, freeze drying, air blast drying, vacuum drying, static drying, vacuum vibration drying, etc. can be used as a three-layer dry water-sealed capsule (three-layer dry capsule). The water content in the membrane of the three-layer dry capsule can be less than 20%, preferably 15% or less, more preferably 10% or less, and further preferably 8% or less.

[0066] In other words, the three-layer dry capsule can be produced by a method comprising the following steps (a) to (c).

[0067] Step (a), using a triple coaxial nozzle, spraying the water-containing core from the inner nozzle, spraying the aforementioned sealing layer from the middle nozzle, and spraying the aforementioned film layer from the outer nozzle, thereby forming three layers of droplets;

[0068] Step (b), contacting the three-layer droplets with a cooling solvent to form a water-sealed pre-capsule;

[0069] Step (c), drying the water-sealed pre-capsules to produce three-layer dry capsules;

[0070] In the case of the above-mentioned three-layer dry capsule, for example, in the case of an easily breakable capsule used in tobacco applications, from the perspectives of manufacturability and breakability, the hardness of the capsule membrane can be exemplified as 0.5 to 40 N, preferably 0.5 to 20 N, the thickness of the capsule membrane can be exemplified as 20 to 500 μm, preferably 40 to 200 μm, from the perspectives of ease of grasping and content, the diameter of the capsule can be exemplified as 0.5 to 15 mm, preferably 1 to 8 mm, and the capsule membrane rate can be exemplified as 5 to 30%.

[0071] The three-layer dry capsule can be easily broken with fingers, and the snapping sound and touch produced when the capsule is broken are pleasant. Therefore, if a capsule containing spices is buried inside a filter attached to tobacco or a filter for installation on tobacco, it can be broken with fingers when smoking to obtain the sound, touch and aroma of the broken capsule. In addition, if a capsule containing flavor is set in a greeting card, the recipient can break the capsule to obtain the sound, touch and aroma. In addition, it can be applied to daily necessities such as pharmaceuticals, health foods, foods, cosmetics, cleaning supplies, etc. It should be noted that the three-layer dry film capsule includes not only the easily breakable capsules used in tobacco applications as described above, but also capsules suitable for oral ingestion.

[0072] As a method for determining the water sealing stability in the capsule of the present invention, in the case of a double-layer solid capsule, the following method can be exemplified: the mass of the capsule after being opened and left under the conditions of 22°C and 18-45% RH (or 5°C and 70% RH, 25°C and 8% RH) is measured to determine the change in water sealing rate over time. If the mass is 75% or more, preferably 85% or more, and more preferably 90% or more after 4 weeks, it is determined that the capsule has water sealing stability. If the mass is 50% or more, preferably 75% or more, more preferably 78% or more, further preferably 80% or more, and particularly preferably 90% or more after 8 weeks, it is determined that the capsule has water sealing stability.

[0073] It should be noted that, in the case of the three-layer dry capsules described above and the easily breakable capsules used for tobacco applications, even if one month (1M) has passed since the capsules were dried, the sound and touch when they were broken with fingers were good, that is, the sound and touch of the broken capsules could be enjoyed, which indicates that the moisture and water-soluble components in the water-containing core have not migrated to the membrane side and the capsules have water-sealing stability.

[0074] As an evaluation method for the water resistance of the capsule of the present invention, a method of visually confirming the migration of the pigment of the water-containing core when the water-sealing capsule is immersed in a preservation solution and stored can be exemplified. When the water and water-soluble components of the water-containing core are encapsulated and stably maintained in the raw capsule, the preservation solution is colorless and has no color change, but when the water and water-soluble components in the water-containing core migrate to the preservation solution side through the membrane, the preservation solution is colored blue, and therefore, it can be visually confirmed that it is unstable.

[0075] Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited to these Examples at all.

[0076] Example

[0077] [Production of water-sealing capsules]

[0078] A triple coaxial nozzle (manufactured by Fuji Capsule Co., Ltd.) was used to spray a membrane liquid having a composition shown in Table 1 from the outermost nozzle, spray an aqueous core liquid having a composition shown in Tables 2 and 3 from the innermost nozzle, and spray an encapsulation layer liquid having a composition shown in Tables 2 and 3 from the middle nozzle, thereby preparing three-layer droplets, and the three-layer droplets were brought into contact with a cooling solvent containing MCT to solidify the membrane liquid, thereby preparing a three-layer water-sealed pre-capsule having a water-containing core, an encapsulation layer that coats the aforementioned water-containing core, and a membrane layer that coats the aforementioned encapsulation layer.

[0079] The outermost gelatin film layer of the three-layer water-sealed pre-capsule was peeled off without drying to make a double-layer water-sealed capsule. If the sealing layer of the double-layer water-sealed capsule exists as the outer layer, water can be sealed, confirming that the gelatin film layer is not necessarily required.

[0080] [Table 1]

[0081] Raw material name Quantity (parts by mass) Gelatin (gel strength 200) 100 glycerin 15 Purified water Moderate

[0082] [Table 2]

[0083]

[0084] Polyethylene bag..Made of low density polyethylene resin, thickness 0.06mm

[0085] Rubber balloon (water balloon)…Made of natural rubber, thickness 0.10mm

[0086] SAIB..Sucrose Acetate Isobutylate (Eastman Chemical)

[0087] The device used for measuring the film thickness at the thinnest part is a high-resolution 3D X-ray microscope "NANO3DX" (manufactured by Rigaku Corporation)

[0088] Equipment used for the measurement of melting point of fats and oils...Differential Scanning Calorimeter "DSC7020" (Hitachi High-Tech Science Corporation)

[0089] Determination start: 0℃, temperature rise: 5℃ / min

[0090] [Table 3]

[0091]

[0092] [Examples 1 to 7]

[0093] For the water-containing cores of Examples 1 to 6, KimicaAlgin IL-2 (manufactured by KIMICA Co., Ltd.) which is sodium alginate was used to thicken the water in order to improve the filling properties. For the sealing layer, four kinds of solid oils were used as the base, and the thickness of the sealing layer was made greater than 70 μm, so that water could be sealed. In Examples 3, 4, and 4-1, a specific gravity adjuster SAIB (manufactured by Eastman Chemical Co., Ltd.) was added to the solid oils in order to improve the filling properties.

[0094] In the water sealing rate test shown in Table 2, the time-dependent changes in the water sealing rate after 4 weeks, 8 weeks, 12 weeks and 16 weeks in the open state under the conditions of 22°C and 18-45% RH (or 5°C and 70% RH, 25°C and 8% RH) were measured. As a reference and target evaluation standard for the water sealing rate, 100% of water was sealed in Comparative Example 1 [polyethylene bag: made of low-density polyethylene resin, thickness 0.06 mm] and Comparative Example 2 [rubber balloon (water balloon): made of natural rubber, thickness 0.10 mm], and the time-dependent changes in the water sealing rate were measured. In terms of the water sealing rate, Comparative Example 1 is superior to Comparative Example 2, and Examples 1 to 7 have water sealing rates that are substantially equal to or superior to Comparative Example 1.

[0095] In Example 4, after seamless filling with three layers to obtain the capsule of Example 4-1, the outer gelatin membrane layer is peeled off without going through the membrane drying process to make a double-layer water-sealed capsule. If the sealing layer exists as the outer layer, water can be sealed. The membrane layer (gelatin) is not necessarily required, and the presence or absence of the membrane layer can be appropriately selected according to the purpose of the product. In addition, according to the results of the time-dependent changes in the water sealing rate in Examples 4 and 4-1, there is no difference in the water sealing rate in the double-layer and triple-layer structures.

[0096] [Examples 8 to 12]

[0097] In Examples 8 to 12 and Comparative Example 3, in order to understand the minimum film thickness of the sealing layer that can seal water, double-layer capsules were prepared in which the minimum film thickness of the sealing layer was changed within 700 to 70 μm, and the water sealing rate was measured after 4 weeks, 8 weeks, 12 weeks, and 16 weeks of exposure under the conditions of 22° C. and 18 to 45% RH. In the measurement of the film thickness of the thinnest part of the sealing layer, a high-resolution 3D X-ray microscope "NANO3DX" (manufactured by Rigaku Corporation) was used to take cross-sectional images obtained by a non-destructive method to confirm the film thickness.

[0098] On the other hand, in terms of water sealing rate, when the thinnest film thickness of the sealing layer was 70 μm (Comparative Example 3), the water sealing rate was significantly reduced and was not suitable as a water sealing capsule. However, when the thinnest film thickness was greater than 70 μm, a good water sealing rate was maintained.

[0099] According to the formulation shown in Table 4 below, each water-sealing capsule was prepared.

[0100] [Table 4]

[0101]

[0102] [Equipment used for rheometer measurement]

[0103] SUN RHEO METER CR-3000EX-L (Sun Scientific Co.,Ltd.)

[0104] Mode: MODE1(Depth) Adapter: No.1φ10mm

[0105] REAL / HOLD: HOLD Entry distance: 3.0mm

[0106] Compression / tension: PRESS Stage moving speed: 20.0mm / min

[0107] Load cell maximum stress: 200N

[0108] (Examples 13 and 14)

[0109] In the water-sealing capsules of Examples 13 and 14, the sealing layer uses an oily substance obtained by mixing a solid oil with a liquid oil squalane believed to have a melting point of -38°C, and the specific gravity of the sealing layer is set to a low specific gravity of 0.795 and 0.815, respectively. In addition, regarding the maximum load measured by the rheometer, it is 0.75 kg in Example 13 and 3.42 kg in Example 14, and a double-layer water-sealing raw capsule with a sealing layer set to be soft can be obtained. Regarding the data after 8 weeks of testing the change of water sealing rate over time, the water sealing rate is maintained better than that of Comparative Example 2 (rubber balloon (water balloon)). Therefore, it is confirmed that the double-layer raw capsule with a specific gravity of 0.795 to 0.815 in the sealing layer maintains an excellent water sealing rate.

[0110] (Examples 15 and 16)

[0111] In the water-sealing capsules of Examples 15 and 16, the sealing layer uses an oily substance obtained by mixing solid fat and liquid fat squalane, and the specific gravity of the sealing layer is set to a slightly higher 0.825 or 0.835. In addition, the maximum load measured by the rheometer is 5.81 kg in Example 15 and 7.18 kg in Example 16, and a double-layer water-sealing solid capsule with a sealing layer set to be relatively hard is obtained.

[0112] (Example 17)

[0113] Regarding the specific gravity of the lipophilic composition in the sealing layer, a double-layer solid capsule using SAIB as a specific gravity adjuster and set to a high specific gravity of 0.99 was obtained as Example 17. The data on the change of water sealing rate over time after 8 weeks of testing showed that the water sealing rate was superior to that of Comparative Example 2 (rubber balloon (water balloon)).

[0114] [Preparation of three-layer water-sealed dry capsules]

[0115] (Examples 18 and 19)

[0116] In Example 18, a capsule having a high specific gravity of 0.99 was prepared as a three-layer dry capsule having a gelatin-based membrane. In Example 19, a capsule having a higher specific gravity of 1.03 was prepared as a three-layer dry capsule having a gelatin-based membrane.

[0117] For Examples 18 and 19, the data after 4 weeks of the time-dependent change test were all above 75%, and the data after 8 weeks of the time-dependent change test were all above 50%, both maintaining a water-dependent rate superior to that of Comparative Example 2 (rubber balloon (water balloon)).

[0118] (Comparative Examples 4 and 5)

[0119] Regarding the specific gravity of the lipophilic composition in the sealing layer, squalane was used as a specific gravity adjuster and the low specific gravity was set to 0.775 and 0.785 as Comparative Examples 4 and 5, respectively, but both were difficult to formulate into three-layer capsules. For formulation, a specific gravity of 0.79 or more is required.

[0120] (Comparative Examples 6 and 7)

[0121] Regarding the specific gravity of the lipophilic composition in the sealing layer, capsules obtained by using SAIB as a specific gravity adjuster and setting the specific gravity to a high specific gravity of 1.065 are respectively used as Comparative Example 6 (double-layer capsules) and Comparative Example 7 (triple-layer capsules). When the specific gravity is greater than 1.05, although the capsule preparation properties are poor, capsules can still be made. However, in terms of the change in water sealing rate over time, it dropped to about 2% after 8 weeks, and the water sealing rate was very poor. The data after 4 weeks and 8 weeks of the test of the change in water sealing rate over time are all lower than the water sealing rate of the above-mentioned Comparative Example 2 (rubber balloon (water balloon)), which cannot be said to be a capsule with excellent water sealing stability.

[0122] [Study on three-layer dry capsules]

[0123] It is known that capsules containing flavorings are buried in tobacco filters, and the capsules are broken when smoking to enjoy the aroma or the sound and touch when the capsules are broken. As the flavors used, oil-soluble flavors that are easy to encapsulate are generally used. In the case of using water-soluble flavors, even if encapsulation is achieved, the water and water-soluble components in the water-soluble flavors will quickly migrate to the capsule membrane side, and the membrane will soften. Therefore, it is pointed out that the sound and touch when the capsules are broken cannot be enjoyed, and further research is being conducted to solve these problems.

[0124] According to the above-mentioned procedure of [Preparation of Water-sealed Capsules], the prepared three-layer water-sealed pre-capsules were dried using a rotary drum type air drier (manufactured by Fuji Capsule Co., Ltd.) to prepare three-layer dry capsules according to the formulation shown in Table 5 below.

[0125] In the water-containing core, water, propylene glycol, and / or ethanol, and / or glycerin are used as components of the water-soluble flavor. In addition, hydroxypropyl cellulose is used as a viscosity-enhancing agent instead of the conventional sodium alginate.

[0126] In the sealing layer, SAIB is used as a specific gravity adjuster, and the specific gravity of the sealing layer is set to a high value of 0.94 or 0.945.

[0127] The film layer has the following film formulations that can be used in tobacco filter embedding capsules and mask filter cartridges: a carrageenan base containing carrageenan and water, a gelatin base containing gelatin and water, or an agar base containing agar and water.

[0128] [Table 5]

[0129]

[0130] (Confirmation of sealing water stability)

[0131] (Examples 20 to 25)

[0132] The thinnest film thickness of the six three-layer dry capsules of Examples 20 to 25 is in the range of 130 μm to 300 μm. In addition, the specific gravity of the sealing layer obtained by using solid oil with a melting point of 44.2°C and specific gravity adjuster SAIB is 0.940 to 0.945, but the physical properties of the sealing layer become hardened, and it becomes a three-layer dry water-sealed capsule. In addition, no matter which of the carrageenan base, gelatin base, and agar base the membrane layer is, it can be easily broken with fingers, and the sound and touch of the snap produced when the capsule is broken are pleasant and good. In addition, even after 1 month (1M) after the capsule is dried, the sound and touch when broken with fingers are good, and the sound and touch of the capsule breaking can be enjoyed. Therefore, it is confirmed that the three-layer dry capsule with the thinnest film thickness of the sealing layer of more than 130 μm has high water-sealing stability.

[0133] It should be noted that the moisture content of the membrane layer of the above 6 kinds of dry capsules was measured using an infrared moisture meter FD-720 (manufactured by Kett Electric Laboratory Co. Ltd.) under the conditions of 1 g of membrane / 105°C / 15 minutes, and all of them were in the range of 8 to 15%. In addition, the thickness was 40 to 200 μm, the hardness was 0.5 to 20 N, the membrane ratio was 5 to 30%, and the capsule diameter was 1 to 8 mm.

[0134] [Production of three-layer raw water-sealed capsules]

[0135] The raw capsule in the prior art is a double-layer capsule in which an oil-soluble component or a lipophilic composition is contained in a soft membrane in a moist state, and its application in cosmetics is known. When the capsule is crushed during use, the capsule membrane is broken and the contents are released to the application site. The contents are mixed with a liquid, cream or semi-solid cosmetic base in a fresh state. The substances used as the contents are usually oil-soluble components and lipophilic compositions, and raw capsules containing water or water-soluble components have not been found. Therefore, a three-layer raw capsule having a water-containing core containing water, which is assumed to be used in the above-mentioned manner, was studied (Examples 26 to 30).

[0136] According to the steps of [Preparation of Water-Sealing Capsules] described above, water-sealing pre-capsules were prepared for each formulation shown in Table 6 below. After washing with running water, the three-layer raw capsules were immersed in a preservation solution (aqueous preservation solution / colorless) containing a preservative (phenoxyethanol) and an antibacterial agent (1,3-butanediol).

[0137] In the water-containing core, Blue No. 1 was added to water as a pigment for visually confirming the pigment migration of the water-containing core in the water resistance test, and sodium alginate was used as a viscosity-enhancing agent.

[0138] In the sealing layer, MCT (Coconad MT, Kao) is used as a liquid oil together with the solid oil, so the sealing layer specific gravity becomes high. For Examples 27 to 30, SAIB is used as a specific gravity adjuster, and the specific gravity of the sealing layer is set to a relatively high 1.01 and 1.00. The film thickness of the thinnest part is 150 μm or more.

[0139] As for the film layer, the following film formulations were used: a carrageenan base comprising carrageenan and water, a gelatin base comprising gelatin and water, or an agar base comprising agar and water.

[0140] As a method for evaluating water resistance, a method of visually confirming the pigment migration of the water-containing core when the three-layer raw capsule is immersed in a preservation solution (preservation water solution / colorless) containing a preservative (phenoxyethanol) and an antibacterial agent (1,3-butylene glycol) and stored. When the water and water-soluble components of the water-containing core are encapsulated in each three-layer raw capsule and are stably maintained, the preservation solution is colorless and has no color change, and it can be confirmed that it has water resistance. On the other hand, when the water and water-soluble components in the water-containing core migrate to the preservation solution side through the membrane, the preservation solution is colored blue and is therefore unstable, and insufficient water resistance can be visually confirmed. The results are shown in Table 6 below.

[0141] [Table 6]

[0142]

[0143] (Examples 26 to 30)

[0144] (Confirmation of water resistance)

[0145] The three-layer capsules of Examples 26 to 30 are all three-layer raw water-sealed capsules, in which the thinnest film thickness of the sealing layer is 150 μm or more, and the specific gravity of the sealing layer obtained by using MCT as the liquid oil is 0.930 to 1.010. In addition, after the capsules are dried, even if the three-layer raw capsules are immersed in a preservation solution for 3 months (3M), there is no pigment migration to the preservation solution side, confirming high water resistance. In addition, these capsules can be easily crushed with fingers and used. As the measured values ​​of the membrane moisture content in the three-layer raw capsules, carrageenan-based membrane capsules: 20.4%; gelatin-based membrane: 49.6%; agar-based membrane capsules: 97.5%. Based on these membrane moisture contents, it can be judged that each membrane is soft and is a raw capsule.

[0146] [Study on water resistance of capsules]

[0147] As shown in the following Table 7 (Examples 31 to 35), double-layer solid capsules or triple-layer capsules having various film thicknesses of the thinnest portion of the sealing layer were produced.

[0148] The water resistance of the water-sealed capsules prepared according to the formulation shown in Table 7 below was evaluated. That is, water was placed in a 20 mL glass vial, one capsule was immersed in the water, and the capsule was stored at room temperature with the lid closed. After 4 weeks, 8 weeks, 12 weeks, and 16 weeks, it was visually confirmed whether the pigment of the water-containing core of the capsule immersed in water leaked out of the capsule over time.

[0149] [Table 7]

[0150]

[0151] (result)

[0152] It can be confirmed from Table 7 that, for Comparative Example 8, the thinnest film thickness of the sealing layer is 60 μm. After 8 weeks, all the capsules leaked pigments and could not obtain water resistance. On the other hand, Example 31 is a double-layer solid water-sealed capsule with a thinnest film thickness of 200 μm or more, and Example 32 is a double-layer solid water-sealed capsule with a thinnest film thickness of 500 μm or more. Even after 16 weeks, the water in the glass bottle did not turn blue, and it was a water-resistant capsule (no pigment leakage). In the three-layer dry capsule of Example 33 with a sealing layer with a thinnest film thickness of 500 μm or more, the gelatin film layer swells over time, but there is no pigment leakage from the water-containing core, and it has water resistance. Examples 34 and 35 are double-layer solid water-sealed capsules with the specific gravity of the sealing layer set to 0.940 and 1.030, and good water-resistant capsules were obtained.

[0153] Industrial Applicability

[0154] The water-sealing capsule of the present invention can be used as a water-sealing capsule that can stably retain hydrophilic volatile substances for a long time in medicines, quasi-drugs, cosmetics, foods, beverages, dairy products, seasonings, supplements, pet food, household daily necessities, tobacco, tobacco substitutes and other hobby products, fertilizers, feeds, detergents and other industrial products and other fields.

Claims

1. A water-sealing capsule, characterized in that it comprises a water-containing core containing water and a sealing layer arranged outside the water-containing core, wherein the sealing layer is formed of a lipophilic composition with a specific gravity of 0.79 to 1.05, and the thinnest part of the sealing layer is 80 μm or more.

2. The water-sealing capsule according to claim 1, It is characterized in that The water-containing core contains a viscosity-adding agent that imparts viscosity to water.

3. The water-sealing capsule according to claim 1, It is characterized in that The lipophilic composition contains a specific gravity adjuster which adjusts the specific gravity of the lipophilic composition to 0.79 to 1.

05.

4. The water-sealing capsule according to claim 1, It is characterized in that The melting point of the lipophilic composition is 16° C. or higher.

5. The water-sealing capsule according to claim 1, It is characterized in that The lipophilic composition contains solid fat having a melting point of 30 to 70°C.

6. The water-sealing capsule according to claim 1, It is characterized in that The lipophilic composition comprises a liquid fat having a melting point below 20°C.

7. The water-sealing capsule according to claim 1, It is characterized in that A film layer is further provided on the outer side of the sealing layer.

8. The water-sealing capsule according to claim 7, It is characterized in that The moisture content of the film layer is 20% or more.

9. The water-sealing capsule according to claim 7, It is characterized in that The moisture content of the film layer is less than 20%.

10. The method for producing the water-sealing capsule according to any one of claims 1 to 9, It is characterized in that Using a triple coaxial nozzle, a water-containing core is sprayed from the inner nozzle, a sealing layer is sprayed from the middle nozzle, and a membrane layer is sprayed from the outer nozzle to form three layers of droplets, which are brought into contact with a cooling solvent to form a water-sealed pre-capsule.

11. The manufacturing method according to claim 10, It is characterized in that Before drying the water-sealed pre-capsule, the membrane layer is peeled off and removed, thereby forming two layers: a water-containing core containing water and a sealing layer disposed outside the water-containing core.

12. The method for manufacturing the water-sealing capsule according to claim 10, It is characterized in that The three-layer water-sealed raw capsules were prepared in such a way that the water-sealed pre-capsules were not allowed to dry out.

13. The method for manufacturing the water-sealing capsule according to claim 10, It is characterized in that The three-layer water-sealed dry capsule is prepared by further undergoing a water-sealed pre-capsule drying process.

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