Microcapsules

Abstract

To provide a microcapsule with excellent dispersibility in water.SOLUTION: A microcapsule comprises a core material comprising 4-hydroxybenzoic acid ester represented by formula (1) [where R1 is a C4 to 22 alkyl group or a C6 to 22 aryl group] or a salt thereof; and a wall membrane coating the core material, with an average particle size of 100-10000 nm.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to microcapsules containing 4-hydroxybenzoic acid ester.

Background Art

[0002] Paraben (also called 4-hydroxybenzoic acid ester or paraoxybenzoic acid ester) has excellent antibacterial and antiseptic effects and is widely used as a preservative in cosmetics, pharmaceuticals, foods, etc. In recent years, a repellent effect against pests such as mites and slugs has also been reported (Patent Document 1).

[0003] A technique has been developed to carry the efficacy of functional compounds such as paraben on the resin itself by kneading them into synthetic resin. For example, an antibacterial resin composition has been proposed that contains at least one agent selected from quaternary ammonium salts and at least one agent selected from 4-hydroxybenzoic acid ester compounds (Patent Document 2).

[0004] On the other hand, in natural fibers such as feathers and cotton and in ready-made products, it is difficult to knead paraben into the fibers. Therefore, when it is desired to impart the efficacy of paraben to these objects, a method of dissolving paraben in a solvent and applying, spraying, atomizing or dipping the solution can be considered.

[0005] As a solvent for dissolving paraben, water is preferable in consideration of safety. However, since the water solubility of paraben decreases as the alkyl chain becomes longer, it may be difficult to dissolve the required amount in an aqueous solution.

[0006] A method of adding a hydrophilic organic solvent such as ethyl alcohol, propylene glycol or acetic acid has been proposed to improve the solubility of paraben in water (Patent Document 3).

Prior Art Documents

Patent Documents

[0007] [Patent Document 1] Japanese Patent Publication No. 2019-69934 [Patent Document 2] Japanese Patent Application Publication No. 10-237317 [Patent Document 3] Japanese Patent Application Publication No. 61-065802 [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] However, it was difficult to completely dissolve parabens with alkyl groups having four or more carbon atoms in water.

[0009] When parabens were used in slurry form (suspension) without being dissolved, it was difficult to maintain a stable dispersion of the parabens, making it difficult to uniformly adhere them to the target object.

[0010] The object of the present invention is to provide microcapsules that exhibit excellent dispersibility in water. [Means for solving the problem]

[0011] In view of the above problems, the inventors conducted diligent research and found that encapsulating parabens with four or more carbon atoms in an alkyl group in microcapsules significantly improves their dispersibility in water, thus completing the present invention.

[0012] In other words, the present invention encompasses the following preferred embodiments. [1] Formula (1) [ka] [In the formula, R1 represents an alkyl group having 4 to 22 carbon atoms or an aryl group having 6 to 22 carbon atoms.] A microcapsule containing an encapsulation comprising a 4-hydroxybenzoic acid ester or a salt thereof, and a wall film covering the encapsulation, with an average particle size of 100 to 10000 nm. [2] The microcapsule according to [1], wherein the salt of the 4-hydroxybenzoic acid ester is an alkali metal salt or an alkaline earth metal salt. [3] The content of 4-hydroxybenzoic acid ester or a salt thereof is 20% by mass or more based on the total mass of the contents, [1] or [2 ] The microcapsules described. [4] R1 represents an alkyl group having 4 to 6 carbon atoms, a microcapsule as described in any of [1] to [3]. [5] R1 is an alkyl group having 6 carbon atoms, a microcapsule as described in any of [1] to [4]. [6] The wall film contains one or more selected from the group consisting of melamine resin, epoxy resin, (meth)acrylic resin, polyurethane resin, polyurea resin, polyamide resin, polyester resin, polyolefin resin, hydroxypropyl methylcellulose, and alginate, as described in any of [1] to [5]. [7] The wall film contains one or more selected from the group consisting of melamine resin, (meth)acrylic resin and polyurethane resin, as described in any of [1] to [6]. A microcapsule dispersion in which microcapsules described in any of [8][1] to [7] are dispersed in an aqueous solvent. [9] The microcapsule dispersion according to [8], wherein the turbidity of the 0.026 mass% microcapsule dispersion is 30 degrees or higher.

[10] The microcapsule dispersion according to [8] or [9], wherein the turbidity reduction rate after standing the 0.026 mass% microcapsule dispersion at 25°C for 7 days is 50% or less. An antifungal agent containing microcapsules as described in any of

[11] [1] to [7]. An insect repellent containing microcapsules as described in any of

[12] [1] to [7]. Textile products to which microcapsules described in any of

[13] [1] to [7] are attached. [Effects of the Invention]

[0013] According to the present invention, microcapsules excellent in dispersibility in water can be obtained.

Brief Description of the Drawings

[0014] [Figure 1] It is a hexyl 4-hydroxybenzoate microcapsule dispersion obtained in Example 1. [Figure 2] It is a solution containing hexyl 4-hydroxybenzoate obtained in Comparative Example 1.

Embodiments for Carrying Out the Invention

[0015] The microcapsules of the present invention contain an inclusion containing a 4-hydroxybenzoic acid ester represented by the formula (1) or a salt thereof and a wall film covering the inclusion.

Chemical formula

[0016] R1 is preferably an alkyl group having 4 to 18 carbon atoms, more preferably an alkyl group having 4 to 6 carbon atoms, and particularly preferably an alkyl group having 6 carbon atoms because of its excellent antibacterial effect.

[0017] Specific examples of 4-hydroxybenzoic acid esters represented by formula (1) used in the present invention include butyl 4-hydroxybenzoate, isobutyl 4-hydroxybenzoate, pentyl 4-hydroxybenzoate, hexyl 4-hydroxybenzoate, heptyl 4-hydroxybenzoate, octyl 4-hydroxybenzoate, ethylhexyl 4-hydroxybenzoate, nonyl 4-hydroxybenzoate, decyl 4-hydroxybenzoate, and hydroxybenzoic acid esters. Isodecyl acid, undecyl 4-hydroxybenzoate, dodecyl 4-hydroxybenzoate, tridecyl 4-hydroxybenzoate, tetradecyl 4-hydroxybenzoate, pentadecyl 4-hydroxybenzoate, hexadecyl 4-hydroxybenzoate, heptadecyl 4-hydroxybenzoate, octadecyl 4-hydroxybenzoate, nonadecyl 4-hydroxybenzoate, eicosyl 4-hydroxybenzoate, henicosyl 4-hydroxybenzoate 、4 One or more substances selected from the group consisting of benzyl hydroxybenzoate, phenyl 4-hydroxybenzoate, p-tolyl 4-hydroxybenzoate, m-tolyl 4-hydroxybenzoate, o-tolyl 4-hydroxybenzoate, 1-naphthyl 4-hydroxybenzoate, and 2-naphthyl 4-hydroxybenzoate.

[0018] The salt of the 4-hydroxybenzoic acid ester represented by formula (1) used in the present invention is preferably an alkali metal salt or an alkaline earth metal salt of the above 4-hydroxybenzoic acid ester. Specific examples of alkali metals include one or more selected from the group consisting of sodium, potassium, and lithium, and examples of alkaline earth metals include magnesium and / or calcium.

[0019] The 4-hydroxybenzoic acid esters or their salts described above may be used alone or in combination of two or more.

[0020] The 4-hydroxybenzoic acid ester or salt used in the present invention may be a commercially available product, or it may be obtained by reacting 4-hydroxybenzoic acid or a 4-hydroxybenzoic acid ester with an alcohol in the presence of a catalyst, as described in Japanese Patent Publication No. 2018-95581 and Japanese Patent Publication No. 2016-210699.

[0021] The contents of the microcapsules of the present invention may contain other agents in addition to 4-hydroxybenzoic acid ester or its salts, but the content of 4-hydroxybenzoic acid ester or its salts is preferably 20% by mass or more, more preferably 40% by mass or more, even more preferably 50% by mass or more, even more preferably 60% by mass or more, particularly preferably 70% by mass or more, even more preferably 80% by mass or more, even more preferably 90% by mass or more, and most preferably 95% by mass or more.

[0022] Other agents include, for example, various additives other than parabens, such as antibacterial agents, antifungal agents, insecticides, insecticides, antialgal agents, algaecides, colorants, flame retardants, heat stabilizers, plasticizers, light stabilizers (UV absorbers, etc.), antistatic agents, fragrances, mold release agents, as well as strengthening agents and powder bulking agents.

[0023] In the microcapsules of the present invention, the wall film covering the encapsulated material can be one or more selected from the group consisting of melamine resin, epoxy resin, (meth)acrylic resin, polyurethane resin, polyurea resin, polyamide resin, polyester resin, polyolefin resin, hydroxypropyl methylcellulose, and alginate. From the viewpoint that the resulting microcapsules are minute and have excellent uniformity, one or more selected from the group consisting of melamine resin, (meth)acrylic resin, and polyurethane resin are preferred.

[0024] The microcapsules of the present invention can be manufactured by methods such as coacervation, interfacial polymerization, in-situ, and sol-gel methods.

[0025] For example, in interfacial polymerization and in-situ methods, an oil-in-water emulsion containing the raw materials for the membrane and encapsulated substances is obtained using an emulsifier or dispersant, and then various polymerization processes are carried out while maintaining the dispersed state to form microcapsules.

[0026] Examples of emulsifiers or dispersants include water-soluble polymers such as polyvinyl alcohol, polyvinylpyrrolidone, gelatin, cationized starch, hydroxypropyl cellulose, carboxymethylcellulose, and polyacrylic acid; sodium lauryl sulfate, alkylbenzene sulfonic acid, polyoxyethylene alkyl ether, and ceti. Ru Examples include surfactants such as trimethylammonium halide; and inorganic dispersants such as calcium carbonate, calcium phosphate, colloidal silica, and montmorillonite. One or more of these can be used.

[0027] The amount of emulsifier or dispersant used is not particularly limited, but generally the amount is adjusted to be in the range of 0.5 to 50% by mass, preferably 2.0 to 30% by mass, relative to the total amount of oil phase components.

[0028] The microcapsules of the present invention may contain a plasticizer that plasticizes the wall film. By containing a plasticizer in the microcapsules, it is possible to adjust the intermolecular forces of the resin (polymer) that forms the wall film and control the sustained release of the encapsulated material outside the microcapsule. In microcapsules containing a plasticizer, a portion of the added plasticizer may be present in the encapsulated material. Such plasticizers include glycols such as ethylene glycol, propylene glycol, and diethylene glycol; polyhydroxy compounds such as glycerin, trimethylolpropane, pentaerythritol, and sorbitol and their partial esters; monocarboxylic acids such as acetic acid, butyric acid, valeric acid, and benzoic acid; dicarboxylic acids such as succinic acid, malonic acid, glutaric acid, and phthalic acid; hydroxycarboxylic acids such as glycolic acid, lactic acid, malic acid, tartaric acid, and citric acid and their esters; diethylene glycol, triethylene glycol, and tetraethylene glycol. Examples include polyethylene glycols and their monoether derivatives such as chol, cellosolve, and carbitol; water-soluble ethers such as tetrahydrofuran, dioxane, glyme, and diglyme; lower ketones such as acetone, methyl ethyl ketone, and cyclohexanone; aprotic polar solvents such as dimethylformamide, dimethyl sulfoxide, acetonitrile, ethylene carbonate, N-methylpyrrolidone, dimethylimidazolidinone, and hexamethylphosphonamide; and amine compounds such as pyridine, triethylamine, ethylenediamine, and ethanolamine.

[0029] The amount of plasticizer used varies depending on the type of wall film, polymerization temperature, and type of plasticizer, but for example, 1 to 100 parts by mass per 100 parts by mass of wall film is preferred.

[0030] Microcapsules having a wall made of melamine resin can be manufactured, for example, by emulsifying and dispersing an oil-soluble liquid containing melamine or a mixture of melamine and urea, etc., and the encapsulated material in water using the above-mentioned emulsifier or dispersant to obtain an oil-in-water droplet type emulsion, then adding formaldehyde to the emulsion and raising the liquid temperature to induce a polymer formation reaction at the oil droplet interface.

[0031] Microcapsules having a wall made of (meth)acrylic resin can be manufactured, for example, by emulsifying and dispersing an oil-soluble liquid containing acrylic acid and its derivatives, acrylamide, methacrylic acid and its derivatives, a monomer having a vinyl group such as acrylonitrile / butadiene, and an encapsulated substance in water using the above-mentioned emulsifier or dispersant to obtain an oil-in-water emulsion, and then polymerizing it at the oil-in-water interface with a polymerization initiator.

[0032] For obtaining (meth)acrylic resin, monomer components containing methacrylic acid esters and / or acrylic acid esters are preferred. Examples of such methacrylic acid esters and / or acrylic acid esters include methyl methacrylate, ethyl methacrylate, propyl methacrylate, hydroxypropyl methacrylate, butyl methacrylate, isopropyl methacrylate, tert-butyl methacrylate, isobutyl methacrylate, n-butyl methacrylate, benzyl methacrylate, isobornyl methacrylate, cyclohexyl methacrylate, tetrahydrofurfuryl methacrylate, mono(ethylene glycol) methyl ether methacrylate, di(ethylene glycol) methyl ether methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 3-hydroxypropyl methacrylate, glycidyl methacrylate, triethylene glycol methyl ether methacrylate, and poly(ethylene glycol) Examples include methyl ether methacrylate, 2-(diethylamino)ethyl methacrylate, dimethylaminoethyl methacrylate, 2-(tert-butylamino)ethyl methacrylate, 2-ethyl(2-oxoimidazolidine-1-yl) methacrylate, methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, isopropyl acrylate, tert-butyl acrylate, isobutyl acrylate, n-butyl acrylate, tetrahydrofurfuryl acrylate, octyl acrylate, octadecyl acrylate, isooctyl acrylate, isobutyl acrylate, isobornyl acrylate, lauryl acrylate, cyanoethyl acrylate, 2-hydroxyethyl acrylate, 2-ethylhexyl acrylate, and 2-[[(butylamino)carbonyl]oxy]ethyl acrylate.

[0033] As polymerization initiators, oil-soluble azo initiators such as azobisisobutyronitrile (AIBN) and peroxide initiators such as benzoyl peroxide are used. Generally, it is preferable to use the polymerization initiator in an amount of 0.001 to 0.05 parts by mass per 1 part by mass of monomer. It is preferable to add the polymerization initiator to the monomer solution immediately before dispersing it in water after the monomer solution has been prepared. The polymerization temperature and polymerization time depend on the initiator used, but generally, polymerization is preferably carried out at 30 to 100°C for 3 to 24 hours. Polymerization is usually carried out under atmospheric pressure.

[0034] Microcapsules having a wall made of polyurethane resin can be produced, for example, by emulsifying and dispersing an oil-soluble liquid containing isocyanates such as hexamethylene diisocyanate, xylylene diisocyanate, and polyhydric isocyanates and polyol adducts, as well as polyols such as polyethylene glycol, polypropylene glycol, trimethylolpropane, polyester polyol, and castor oil that react with the isocyanates, in an aqueous solvent using the above-mentioned emulsifier or dispersant to obtain an oil-in-water droplet type emulsion, and then raising the liquid temperature to induce a polymer formation reaction at the oil droplet interface.

[0035] The average particle size of the microcapsules of the present invention is 100 to 10000 nm, preferably 150 to 5000 nm, more preferably 200 to 2000 nm, even more preferably 250 to 1500 nm, even more preferably 300 to 1000 nm, and particularly preferably 400 to 700 nm, from the viewpoint of improving dispersibility in water and retention of the contents contained within the microcapsules.

[0036] In this specification, the average particle diameter is defined as the median diameter (D) based on volume. 50 This means, for example, that it is measured by a particle size distribution analyzer MT3200 (manufactured by Nikkiso Co., Ltd.).

[0037] The particle size of the microcapsules is determined by the size of the emulsion droplets being dispersed. Dispersion is performed by stirring with the stirring blades attached to the polymerization tank, or by using a milder, homomixer, or ultrasonic mixer. waveThis is done by stirring with a homogenizer or similar device.

[0038] In the microcapsules of the present invention, the ratio of the encapsulated material to the wall film is preferably selected such that the wall film is 30 to 70 parts by mass, more preferably 40 to 60 parts by mass, per 100 parts by mass of the encapsulated material.

[0039] The microcapsule dispersion obtained by the above manufacturing method may be used as is as various formulations, or the solvent may be removed from the dispersion by filtration, drying, etc., and used as a microcapsule solid preparation. In this case, washing with deionized water or the like may be performed as needed. Furthermore, the microcapsule solid preparation may be dispersed again in an aqueous solvent and used as a dispersion.

[0040] An aqueous solvent refers to a solvent containing water, and may be water alone or a mixed solvent of water and a water-miscible organic solvent. The type of water is not particularly limited, and any of distilled water, pure water, ultrapure water, deionized water, tap water, etc., can be used. When using a mixed solvent of water and a water-miscible organic solvent, the proportion of water in the mixed solvent is preferably 50% by volume or more, more preferably 60% by volume or more, even more preferably 70% by volume or more, and particularly preferably 80% by volume or more, with water alone being the most preferable aqueous solvent.

[0041] The water-miscible organic solvent is not particularly limited as long as it is miscible with water at room temperature, and examples include alcohols such as methanol and ethanol; ethers such as tetrahydrofuran; ketones such as acetone; and amides such as dimethylformamide and dimethylacetamide.

[0042] The microcapsule dispersion of the present invention preferably has a turbidity of 30 degrees or higher, more preferably 35 degrees or higher, and even more preferably 40 to 300 degrees, when the microcapsule content is adjusted to 0.026% by mass. Having a turbidity within this range ensures that the microcapsules are uniformly dispersed in the solvent, allowing the various effects of parabens, such as their antibacterial properties, to be expressed evenly.

[0043] The microcapsule dispersion of the present invention is preferably prepared with a microcapsule content of 0.026% by mass, and after standing at 25°C for 7 days, the turbidity reduction rate, expressed as [(turbidity before standing - turbidity after standing) / turbidity before standing] × 100 (%), is 50% or less, more preferably 45% or less, and even more preferably 40% or less. Maintaining the dispersion state for a long period of time is possible when the turbidity reduction rate of the microcapsule dispersion is within the above range.

[0044] In this specification, "turbidity" refers to the value measured using formazin standard solution in accordance with JIS K 0101 (Test Methods for Industrial Water). Turbidity can be measured using a spectrophotometer such as NanoDrop2000 (manufactured by ThermoFisher SCIENTIFIC).

[0045] To measure turbidity, first, prepare dilutions (20-400°C) by diluting formazin standard solution (400°C) to the specified concentration, and create a calibration curve based on the absorbance (wavelength 660nm) of each dilution. Then, measure the absorbance (wavelength 660nm) of the microcapsule dispersion and calculate the turbidity from the calibration curve. Commercially available formazin standard solution (400°C) can be used.

[0046] The various formulations containing the microcapsules of the present invention may optionally contain other additives, such as dispersants, surfactants, thickeners, preservatives other than parabens, specific gravity adjusters, etc.

[0047] Examples of dispersants include polyvinyl alcohol and its modified products, polyacrylamide and its derivatives, ethylene-vinyl acetate copolymer, styrene-maleic anhydride copolymer, ethylene-maleic anhydride copolymer, isobutylene-maleic anhydride copolymer, polyvinylpyrrolidone, ethylene-acrylic acid copolymer, vinyl acetate-acrylic acid copolymer, carboxymethylcellulose, methylcellulose, casein, gelatin, starch derivatives, gum arabic, and sodium alginate.

[0048] Examples of surfactants include nonionic surfactants, cationic surfactants, anionic surfactants, and amphoteric surfactants.

[0049] Examples of thickening agents include mineral powders such as aluminum magnesium silicate, smectite, bentonite, hectorite, and dry-process silica, as well as alumina sols, which have a thickening effect in water.

[0050] Other preservatives besides parabens include, for example, sodium benzoate and salicylic acid derivatives.

[0051] Examples of specific gravity adjusting agents include water-soluble salts such as sodium sulfate, polysaccharides such as glucose, and water-soluble fertilizers such as urea.

[0052] The microcapsules of the present invention can be used in various formulations, such as antibacterial agents, antifungal agents, insecticides, herbicides, algaecides, and insect repellents.

[0053] The formulations containing the microcapsules of the present invention described above include sprays, aerosols, and Pap It can be prepared in various forms such as formulations, liquids, coatings, mats, sheets, tapes, powders, granules, gels, creams, films, containers, and paints.

[0054] The formulation containing the microcapsules of the present invention is particularly suitable for use as an antifungal agent.

[0055] Examples of target dermatophytes include Trichophyton tonsurans, Trichophyton violaceum, Trichophyton rubrum, Trichophyton mentagrophytes, Trichophyton verrucosum, Microsporum canis, and Microsporum gypseum.

[0056] The anti-dermatophyte agent containing microcapsules of the present invention can be applied to a treated area or body on which dermatophytes can grow or which may be contaminated by dermatophytes, thereby preventing contamination by dermatophytes.

[0057] The processing area or object can be applied to a wide range of products, including living environments such as bathrooms and living rooms, and clothing such as clothes and footwear. Specifically, examples include clothing such as suits, dress shirts, T-shirts, polo shirts, blouses, slacks, skirts, and underwear; footwear such as socks, tabi socks, shoes, boots, sandals, flip-flops, slippers, and insoles; accessories such as hats, scarves, and gloves; bedding such as futons, sofas, blankets, and pillows; textile and leather products such as towels, bath mats, doormats, and carpets; and building materials such as tatami mats, tiles, flooring, wall coverings, and flooring.

[0058] Methods for applying the antifungal agent containing the microcapsules of the present invention to a treated area include sprinkling, spraying, and coating, and methods for applying to the treated object include kneading, sprinkling, spraying, coating, or incorporating Soaking These are some examples of methods.

[0059] The microcapsules of the present invention are particularly preferably attached to textile products.

[0060] Various methods commonly used for processing fibers can be applied to attach the microcapsules of the present invention to a fibrous material, but among them, the padding method, spraying method, coating method, and bath adsorption / exhaustion method are preferred. Furthermore, considering the normal production process, the padding method is preferred when the fibrous material is in the form of woven fabrics such as woven or knitted fabrics, and the bath adsorption / exhaustion method is preferred when the fibrous material is in the form of yarn (including hanks, cheeses, and beams), pantyhose, tights, etc. In addition, in order to ensure uniform processing, it is preferable to perform pretreatment such as desizing, scouring, and bleaching of the fibrous material prior to the application of microcapsules.

[0061] The type of fiber material is not particularly limited and can be used without restriction, including synthetic fibers, regenerated fibers, and natural fibers. Specifically, examples include synthetic fibers such as polyester, polyamide, polyurethane, acrylic, vinylon, vinyl chloride, and polypropylene; semi-synthetic fibers such as diacetate and triacetate; regenerated fibers such as rayon, cupro, and Tencel; and natural fibers such as cotton, linen, kenaf, pulp, wool, and silk. Furthermore, two or more of these may be used in any proportion after being blended, mixed, spun, or interwoven. The form of such fibers may be any form, such as woven fabric, knitted fabric, or nonwoven fabric.

[0062] The formulation containing the microcapsules of the present invention is particularly suitable for use as an anti-algal agent.

[0063] The algae that are targeted include, color These include algae belonging to the divisions Plantae, Rhodophyta, Cryptocoryne, Brown Plantae, Euglena, Prasinophyta, and Chlorophyta (for example, drugs belonging to classes such as cyanobacteria, Euglena, green algae, diatoms, and Prasinophytes), and specifically the following algae:

[0064] Cyanobacteria include the genera Oscillatoria, such as Oscillatoria laetevirens, and Nostoc, such as Nostoc commune. Euglena include the genera Euglena, such as Euglena gracilis.

[0065] Green algae, including species such as Chlorella vulgaris (genus Chlorella), Chlamydomonas (genus Chlamydomonas reinhardtii), and Ulothrix (genus Ulothrix variabilis).

[0066] Diatoms include genera such as Eolimna minima, Gomphonema parvulum, Tabella flocculosa, and Melosira granulata.

[0067] Among these, the genera Oscillatoria, Nostoc, Chlorella, Eolimna, and Gomphonema are preferably protected from algae, with Eolimna being particularly favorably protected.

[0068] Furthermore, hydra, sea anemones, corals, and other coelenterates that live in symbiosis with or feed on the above-mentioned algae, as well as fringed algae. Moss Insects, bryozoans, and bryozoans Shina Which tentacled animals, striped barnacles, triangular barnacles, spotted barnacles, red barnacles, workman Arthropods such as star anemones, mud worms, shrimp, and crabs; annelids such as spiral polychaetes, layered worms, scale worms, ciliates, and pygmy polychaetes; mollusks such as purple mussels, mussels, Pacific oysters, and freshwater mussels; protochordates such as white sea squirts, ghost sea squirts, and red sea squirts; purple sponges, Na It is also effective against sea sponges such as the humid sponge.

[0069] The algal inhibitor containing microcapsules of the present invention can be applied to a treated area or object where algae can grow, and can suppress or prevent the growth of algae.

[0070] Examples of areas or objects to be treated include ships (especially the bottoms), swimming pools, aquariums, fishing nets, seaweed nets, fishing cages, fishing gear, underwater reefs, underwater structures, seawater inlet pipes, buoys, etc., houses (especially exterior walls, roofs, kitchens, bathrooms, verandas, storage rooms, etc.), flower pots, planters, the bottoms or surrounding areas of seedling pots, and the inside of drainage outlets. It can also be applied to organisms that can serve as a nutrient source for algae, or the areas surrounding such organisms.

[0071] Methods for applying the algal inhibitor containing the microcapsules of the present invention to a treated area include sprinkling, spraying, coating, etc., and methods for applying to the treated object include kneading, sprinkling, spraying, coating, or incorporating Soaking These are some examples of methods.

[0072] The formulation containing the microcapsules of the present invention is particularly suitable for use as an insect repellent.

[0073] Examples of pests targeted include slugs, snails, land snails, mites, cockroaches, bees, flies, fly larvae, mosquitoes, horseflies, fleas, centipedes, bed bugs, stable flies, clothes moths, woodlice, ants, termites, leafhoppers, whiteflies, millipedes, pill bugs, and confused flour beetles.

[0074] By applying the insect repellent containing the microcapsules of the present invention to a treated area or object, insects can be repelled from that area or object. Alternatively, the insect repellent may be supported on a carrier such as a nonwoven fabric, sheet, or inorganic carrier, and these may be placed in locations where insects are to be repelled.

[0075] Examples of areas or objects to be treated include the bottom or surrounding areas of flower pots, planters, and seedling pots, the space between the bottom and the soil, the inside of drainage holes, and under fallen leaves. Furthermore, organisms themselves or their surrounding areas that can serve as a nutrient source for pests are also included in the areas or objects to be treated in this invention. Examples include crops themselves, the fields in which they are cultivated, orchards, and flowerbeds where flowers are grown.

[0076] Examples of indoor areas or objects to be treated include kitchens, bathrooms, verandas, and storage rooms in ordinary homes and restaurants.

[0077] Methods for applying the insect repellent containing the microcapsules of the present invention to a treatment area include sprinkling, spraying, and coating, and means of application to the treatment object include kneading, sprinkling, spraying, coating, or incorporating Soaking These are some examples of methods. [Examples]

[0078] The present invention will be described in detail below with reference to examples, etc., but these are not intended to limit the scope of the present invention.

[0079] The average particle size, anti-dermatophytogenic activity, and turbidity shown in the examples were measured by the following method. <Average particle size> The average particle size (D) of the microcapsules in the microcapsule dispersion prepared in the example. 50 The particle size distribution was measured using a particle size analyzer (MT3200, manufactured by Nikkiso Co., Ltd.). <Anti-dermatophyte> 1.0 mL of the microcapsule dispersion (microcapsule concentration 26%) prepared in the example and 9.0 mL of sterile water were added to a sample tube and stirred for 1 minute using a vortex mixer to prepare a 10-fold dilution. A similar procedure was performed to prepare a 10-fold dilution. 7 Dilutions up to 1:1 (microcapsule concentration 0.026 ppm) were prepared. For each target dermatophyte, 90 μL of the microcapsule dispersion or microcapsule dispersion dilution was added to the wells in the 1st to 6th rows from the left of a 96-well microplate, with the concentration decreasing tenfold from top to bottom. In addition, 90 μL of sterile water was added to the other wells to serve as a blank. Fill each well with 80 μL of soybean casein digest (SCD) medium and a suspension of the target dermatophyte (2.5 × 10⁴). 4 After adding 10 μL of cfu / mL to each sample, the samples were incubated at 30°C for 72 hours. After culturing, the growth of dermatophytes was visually observed to confirm that dermatophytes had grown in the blank sample, and the minimum inhibitory concentration (MIC: μg / mL) was calculated. The minimum inhibitory concentration was measured according to the Japanese Society of Chemotherapy standard method (micro-liquid dilution method).

[0080] The dermatophytes used in the tests are listed below. [Tinea fungi being tested] Trichophyton mentagrophytes NBRC-32409 Dermatophytes 2: Trichophyton rubrum: NBRC-9185

[0081] <Turbidity> Formazin standard solution (turbidity 400 degrees, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was diluted 2, 4, 8, and 16 times with purified water to prepare standard solutions with turbidity of 200, 100, 50, and 25 degrees. The absorbance of each standard solution with different turbidity (measurement wavelength: 660 nm) was measured using the absorbance measuring instrument described below, and a calibration curve was created. 1 μL of the microcapsule dispersion prepared in the example and 999 μL of purified water were placed in a sample tube and stirred for 30 seconds using a vortex mixer to prepare a 1000-fold dilution (0.026% by mass of microcapsules). The absorbance (measurement wavelength: 660 nm) was measured and the turbidity was determined by applying it to the prepared calibration curve. The measured samples were left to stand at 25°C, and the absorbance was measured again after 1 day and 7 days to determine the turbidity. Absorbance measurement equipment: Spectrophotometer NanoDrop2000 (manufactured by ThermoFisher SCIENTIFIC)

[0082] [Manufacturing of microcapsule dispersions] [Example 1] In a 300 mL flask equipped with a stirrer, thermometer, reflux condenser, and inert gas insert, 0.6 g of polyvinyl alcohol and 120 mL of distilled water were added and stirred until dissolved to obtain a polyvinyl alcohol solution. To this, a mixed solution consisting of 21 g of methyl methacrylate, 9 g of methacrylic acid, 0.9 g of benzoyl peroxide, 17.5 g of propylene glycol, and 18.8 g of hexyl 4-hydroxybenzoate was added while continuously stirring at 500 rpm. After heating at 65 °C for 5 hours while continuing to stir, the suspension was cooled to room temperature to obtain a hexyl 4-hydroxybenzoate microcapsule dispersion. The average particle size, anti-dermatophytogenic activity, and turbidity of the obtained microcapsule dispersion were measured. The results are shown in Table 1. The appearance of the microcapsule dispersion is shown in Figure 1.

[0083] [Example 2] A butyl 4-hydroxybenzoate microcapsule dispersion was obtained in the same manner as in Example 1, except that hexyl 4-hydroxybenzoate was replaced with butyl 4-hydroxybenzoate. The average particle size, anti-dermatophytogenic activity, and turbidity of the obtained microcapsule dispersion were measured. The results are shown in Table 1.

[0084] [Example 3] (Reference example) A hexadecyl 4-hydroxybenzoate microcapsule dispersion was obtained in the same manner as in Example 1, except that hexyl 4-hydroxybenzoate was replaced with hexadecyl 4-hydroxybenzoate. The average particle size and turbidity of the microcapsules in the obtained microcapsule dispersion were measured. The results are shown in Table 1.

[0085] [Comparative Example 1] 1 mL of purified water and 0.1 g of hexyl 4-hydroxybenzoate were added to a sample tube and stirred with a vortex mixer for 30 seconds. However, hexyl 4-hydroxybenzoate crystals settled, and a liquid in which hexyl 4-hydroxybenzoate was dispersed was not obtained. The appearance is shown in Figure 2.

[0086] [Table 1]

[0087] The microcapsule dispersions of the present invention (Examples 1-3) exhibit excellent dispersibility in water because the average particle size of the microcapsules is small, ranging from 100 to 10,000 nm, and the rate of decrease in turbidity over time is low. Furthermore, it is understood that Examples 1 and 2 show antibacterial effects against dermatophytes even in the microencapsulated state. In addition, the microcapsules obtained in Example 3 are particularly useful for use as an insect repellent.

[0088] Acquisition of microencapsulated powder [Example 4] The microcapsule dispersion obtained in the same manner as in Example 1 was filtered, and the resulting solid was washed with 200 mL of deionized water. After drying under reduced pressure at 60°C, 28.3 g of hexyl 4-hydroxybenzoate microcapsule powder was obtained.

[0089] [Example 5] The microcapsule dispersion obtained in the same manner as in Example 2 was filtered, and the resulting solid was washed with 200 mL of deionized water. After drying under reduced pressure at 60°C, 27.4 g of butyl 4-hydroxybenzoate microcapsule powder was obtained.

Claims

1. Formula (1) 【Chemistry 1】 [In the formula, R １ [This indicates an alkyl group with 4 to 6 carbon atoms.] A microcapsule containing an encapsulation comprising a 4-hydroxybenzoic acid ester or a salt thereof, and a wall film covering the encapsulation, wherein the average particle size is 100 to 10000 nm.

2. The microcapsule according to claim 1, wherein the salt of 4-hydroxybenzoic acid ester is an alkali metal salt or an alkaline earth metal salt.

3. The microcapsule according to claim 1 or 2, wherein the content of 4-hydroxybenzoic acid ester or a salt thereof is 20% by mass or more based on the total mass of the encapsulated material.

4. R １ The microcapsule according to any one of claims 1 to 3, wherein is an alkyl group having 6 carbon atoms.

5. The microcapsule according to any one of claims 1 to 4, wherein the wall film contains one or more selected from the group consisting of melamine resin, epoxy resin, (meth)acrylic resin, polyurethane resin, polyurea resin, polyamide resin, polyester resin, polyolefin resin, hydroxypropyl methylcellulose, and alginate.

6. The microcapsule according to any one of claims 1 to 5, wherein the wall film contains one or more selected from the group consisting of melamine resin, (meth)acrylic resin, and polyurethane resin.

7. A microcapsule dispersion in which microcapsules according to any one of claims 1 to 6 are dispersed in an aqueous solvent.

8. The microcapsule dispersion according to claim 7, wherein the turbidity of the 0.026% by mass microcapsule dispersion is 30 degrees or higher.

9. The microcapsule dispersion according to claim 7 or 8, wherein the turbidity reduction rate after standing the 0.026% by mass microcapsule dispersion at 25°C for 7 days is 50% or less.

10. An antifungal agent containing microcapsules according to any one of claims 1 to 6.

11. An insect repellent containing microcapsules according to any one of claims 1 to 6.

12. A textile product to which microcapsules according to any one of claims 1 to 6 are attached.

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