Odor reducer for natural rubber odor and natural rubber article using the same

Abstract

To provide an odor reducer that enables effective reduction of natural rubber odor.SOLUTION: The odor reducer for natural rubber odor according to the present invention includes, as active ingredients, n-undecanal, 6-acetyl-1,1,2,4,4,7-hexamethyltetralin, and 2-methoxynaphthalene.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a technology for reducing the odor of natural rubber. [Background technology]

[0002] BACKGROUND ART Conventionally, a technique has been known in which a specific fragrance component is used as a masking agent to reduce the putrid odor or irritating odor of natural rubber products.

[0003] For example, Patent Document 1 discloses a rubber odor modulator containing woody-spicy aroma components, including at least one selected from a first group consisting of juniper berry oil and estragon oil, at least one selected from a second group consisting of cinnamon cassia, pink pepper extract, and black pepper extract, and at least one selected from a third group consisting of vanillin and cypress extract.

[0004] Furthermore, Patent Document 2 discloses a cross-linked rubber composition to which a fragrance containing any one of β-citronellol, 4-tert-butylcyclohexyl acetate, allyl heptanoate, CIS-3-hexenyl acetate, allyl hexanoate, and calone has been added as a fragrance component, and which does not have a noticeable rubber odor. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent Publication No. 2021-126326 [Patent Document 2] Patent Publication No. 2021-138882 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the fragrances of the prior art have not been able to fully meet the demand for effectively reducing the odor of natural rubber.

[0007] The present invention was made in consideration of the above circumstances, and aims to provide an odor-reducing agent that effectively reduces the odor of natural rubber and a fragrance composition containing the same. Another aim of the present invention is to provide an odor-reducing method that effectively reduces the odor of natural rubber. A further aim of the present invention is to provide a natural rubber article with a reduced natural rubber odor. [Means for solving the problem]

[0008] The natural rubber odor reducer of the present invention is characterized by containing n-undecanal, 6-acetyl-1,1,2,4,4,7-hexamethyltetralin, and 2-methoxynaphthalene as active ingredients. The "natural rubber odor reducer" of the present invention is a composition comprising a combination of fragrance compounds, which is highly effective in reducing the natural rubber odor. The inventors discovered that a composition comprising a combination of n-undecanal, 6-acetyl-1,1,2,4,4,7-hexamethyltetralin, and 2-methoxynaphthalene significantly reduces the natural rubber odor, leading to the completion of the present invention.

[0009] The mechanism by which the odor of natural rubber can be effectively reduced by using the odor-reducing agent of the present invention is not limited to any particular theory, but is thought to be that the substances that cause the natural rubber odor (typical examples include isovaleric aldehyde, propionic acid, formic acid, butyric acid, n-valeric acid, trimethylamine, 2-pyrrolidone, etc.) mix with the active ingredients contained in the odor-reducing agent of the present invention, resulting in a reduction in the intensity of the natural rubber odor so that it becomes undetectable.

[0010] The fragrance composition of the present invention is characterized by containing the natural rubber odor-reducing agent of the present invention.

[0011] The method for reducing the odor of natural rubber of the present invention is characterized by using the odor-reducing agent and / or the fragrance composition.

[0012] The natural rubber article of the present invention is characterized by containing n-undecanal, 6-acetyl-1,1,2,4,4,7-hexamethyltetralin, and 2-methoxynaphthalene. [Effects of the Invention]

[0013] According to the present invention, it is possible to effectively reduce the natural rubber odor of natural rubber articles and impart a refreshing fragrance to the natural rubber articles of the present invention, and the effect of reducing the natural rubber odor lasts for a long period of time. DETAILED DESCRIPTION OF THE INVENTION

[0014] (Odor reducer for natural rubber odor) The natural rubber odor reducer of the present invention (hereinafter sometimes referred to as "the odor reducer of the present invention") is characterized by containing n-undecanal, 6-acetyl-1,1,2,4,4,7-hexamethyltetralin, and 2-methoxynaphthalene (hereinafter sometimes referred to as the active ingredients of the present invention) as active ingredients.

[0015] In this specification, "reducing the odor of natural rubber" means weakening the natural rubber odor (the odor derived from natural rubber), and does not necessarily mean completely eliminating the natural rubber odor. Preferably, the odor-reducing agent not only reduces the natural rubber odor but also imparts a refreshing scent that is not unpleasant in various situations in which natural rubber products are used. Here, a refreshing scent is a scent that does not give the impression of a strong scent, but leaves a natural, clean impression. This allows the odor-reducing agent to be used without any unpleasant feeling, regardless of the situation.

[0016] The active ingredients of this odor-reducing agent consist of n-undecanal, 6-acetyl-1,1,2,4,4,7-hexamethyltetralin, and 2-methoxynaphthalene.

[0017] One of the active ingredients, n-undecanal, has the following structure: [ka]

[0018] One of the active ingredients, 6-acetyl-1,1,2,4,4,7-hexamethyltetralin (also known as "Tonalid" (registered trademark)), has the following structure: [ka]

[0019] One of the active ingredients, 2-methoxynaphthalene, has the following structure: [ka]

[0020] The active ingredient of the present invention can be purchased as a commercially available product or can be obtained by any method, such as by synthesis using known methods.

[0021] When the mass of all active ingredients is taken as 100%, the content of each active ingredient in all active ingredients can be determined arbitrarily depending on the desired odor reduction effect. As a non-limiting example, the lower limit of the content of n-undecanal in the active ingredients may be 10 mass%, 20 mass%, or 30 mass%, and the upper limit may be 70 mass%, 60 mass%, or 50 mass%.

[0022] The lower limit of the content of 6-acetyl-1,1,2,4,4,7-hexamethyltetralin in all active ingredients may be 5 mass%, 10 mass%, or 20 mass%, and the upper limit may be 70 mass%, 60 mass%, or 50 mass%.

[0023] 2-Methoxynaphthalene constitutes the remainder of the active ingredients, and the total of n-undecanal and 6-acetyl-1,1,2,4,4,7-hexamethyltetralin is 100% by mass, but the lower limit of the 2-methoxynaphthalene content may be 3%, 5%, or 10% by mass, and the upper limit may be 50%, 40%, or 30% by mass. This is because, when the contents of the active ingredients are within the above ranges, the effect of reducing the natural rubber odor is particularly high, and a refreshing scent is also obtained.

[0024] As an example of the concentration of the active ingredient in the odor reducer, particularly when the odor reducer contains ingredients other than the active ingredient and its solvent, the concentration of the active ingredient in the odor reducer can be determined arbitrarily depending on the target and fragrance characteristics of the odor reducer, and can be set to an appropriate concentration so that the odor reducer can be added at a concentration that provides an odor-reducing effect to the target. For example, the concentration can be 10 ppm to 90 mass%, more specifically, the lower limit can be any of 10 ppm, 100 ppm, 1000 ppm, 1 mass%, 5 mass%, 10 mass%, 15 mass%, 20 mass%, 25 mass%, 30 mass%, 35 mass%, 40 mass%, 45 mass%, 50 mass%, 55 mass%, 60 mass%, 65 mass%, 70 mass%, 75 mass%, 80 mass%, and 85 mass%, and the upper limit can be any of 90 mass%, 85 mass%, and 95 mass%. The range may be any of the following: 80 mass%, 75 mass%, 70 mass%, 65 mass%, 60 mass%, 55 mass%, 50 mass%, 45 mass%, 40 mass%, 35 mass%, 30 mass%, 25 mass%, 20 mass%, 15 mass%, 10 mass%, 5 mass%, 1 mass%, 1000 ppm, and 100 ppm, and may be within a range defined by any combination of these lower and upper limits.

[0025] The odor reducing agent of the present invention may contain, in addition to the active ingredient, any other ingredients, such as a solvent, a dispersion medium, an odor reducing ingredient other than the active ingredient, other fragrance-imparting ingredients, an auxiliary ingredient such as an antioxidant ingredient, etc.

[0026] (Fragrance composition) The fragrance composition of the present invention (hereinafter sometimes referred to as "the fragrance composition of the present invention") is not particularly limited as long as it contains the natural rubber odor reducing agent of the present invention, and preferably contains a fragrance component (excluding n-undecanal, 6-acetyl-1,1,2,4,4,7-hexamethyltetralin, and 2-methoxynaphthalene) and the natural rubber odor reducing agent of the present invention. A fragrance composition formulated with the natural rubber odor reducing agent of the present invention can reduce the natural rubber odor and impart a desired fragrance note.

[0027] Specific examples of optional other components that may be contained in the fragrance composition in addition to the odor-reducing agent include various types of fragrance compounds, fragrance compositions, colorants, functional substances, solvents, surfactants (dispersants or emulsifiers), specific gravity adjusters, antioxidants, etc. These components may be used alone or in combination.

[0028] Examples of various types of fragrance compounds include natural essential oils, natural fragrances, and synthetic fragrances described in the "Japan Patent Office Gazette, Collection of Well-Known and Commonly Used Techniques (Fragrances) Part II Food Flavors, published January 14, 2000," "Survey on the Actual Use of Food Flavoring Compounds in Japan" (2000 Ministry of Health, Labour and Welfare Science Research Report, Japan Flavor and Flavor Manufacturers Association, published March 2001), and "Synthetic Fragrances: Chemistry and Product Knowledge" (revised and expanded edition published December 20, 2016, edited by the Synthetic Fragrances Editorial Committee, Chemical Daily Co., Ltd.).

[0029] Specific examples of fragrance compounds include hydrocarbon compounds, alcohol compounds, aldehyde compounds, ketone compounds, furan or ether compounds, ester compounds, lactone compounds, acid compounds, nitrogen-containing compounds, sulfur-containing compounds, natural essential oils, etc. These fragrance compounds may be used alone or in combination.

[0030] Examples of the hydrocarbon compounds include monoterpenes such as α-pinene, β-pinene, myrcene, camphene, and limonene, sesquiterpenes such as valencene, cedrene, caryophyllene, and longifolene, and 1,3,5-undecatriene.

[0031] Examples of the alcohol compound include saturated or unsaturated alcohols such as butanol, pentanol, 3-octanol, hexanol, (Z)-3-hexen-1-ol, prenol, and 2,6-nonadienol; terpene alcohols such as linalool, geraniol, citronellol, tetrahydromyrcenol, farnesol, nerolidol, cedrol, and terpineol; and aromatic alcohols such as benzyl alcohol, phenylethyl alcohol, and cinnamyl alcohol.

[0032] Examples of the aldehyde compound include saturated or unsaturated aldehydes such as acetaldehyde, hexanal, octanal, decanal, (E)-2-hexenal, and 2,4-octadienal; terpene aldehydes such as citronellal, hydroxycitronellal, citral, myrtenal, and perillaldehyde; and aromatic aldehydes such as benzaldehyde, cinnamaldehyde, amylcinnamaldehyde, vanillin, ethyl vanillin, heliotropin, and p-tolylaldehyde.

[0033] Examples of the ketone compounds include saturated or unsaturated ketones such as 2-heptanone, 2-undecanone, 1-octen-3-one, and acetoin; diketones and hydroxyketones such as diacetyl, 2,3-pentanedione, maltol, ethyl maltol, cyclotene, and 2,5-dimethyl-4-hydroxy-3(2H)-furanone; terpene ketones such as carvone, menthone, and nootkatone; ketones derived from terpene degradation products such as α-ionone, β-ionone, and β-damascenone; and aromatic ketones such as raspberry ketone.

[0034] Examples of the furan or ether compound include furfuryl alcohol, furfural, rose oxide, linalool oxide, menthofuran, theaspirane, estragole, eugenol, and 1,8-cineole.

[0035] Examples of the ester compound include aliphatic esters such as ethyl acetate, isoamyl acetate, ethyl butyrate, ethyl isobutyrate, isoamyl butyrate, ethyl 2-methylbutyrate, ethyl 3-methylbutyrate, 2-methylbutyl isobutyrate, ethyl hexanoate, allyl hexanoate, ethyl heptanoate, ethyl caproate, isoamyl isovalerate, and ethyl nonanoate; terpene alcohol esters such as linalyl acetate, geranyl acetate, lavandulyl acetate, and terpenyl acetate; and aromatic esters such as benzyl acetate, benzyl butyrate, methyl salicylate, benzyl salicylate, methyl cinnamate, cinnamyl propionate, ethyl benzoate, cinnamyl isovalerate, and ethyl 3-methyl-2-phenylglycidate.

[0036] Examples of the lactone compound include saturated or unsaturated lactones such as γ-decalactone, γ-dodecalactone, δ-decalactone, δ-dodecalactone, 7-decen-4-olide, and 2-decen-5-olide.

[0037] Examples of the acid compound include saturated or unsaturated fatty acids such as acetic acid, butyric acid, octanoic acid, isovaleric acid, caproic acid, stearic acid, oleic acid, linoleic acid, and linolenic acid.

[0038] Examples of the nitrogen-containing compound include pyridine, alkyl-substituted pyrazine, methyl anthranilate, and trimethylpyrazine.

[0039] Examples of the sulfur-containing compounds include methanethiol, dimethyl sulfide, dimethyl disulfide, allyl isothiocyanate, 3-methyl-2-butene-1-thiol, 3-methyl-2-butanethiol, 3-methyl-1-butanethiol, 2-methyl-1-butanethiol, and furfuryl mercaptan.

[0040] Examples of the natural essential oils include sweet orange, bitter orange, petitgrain, lemon, bergamot, mandarin, neroli, peppermint, spearmint, lavender, chamomile, rosemary, eucalyptus, sage, basil, rose, hyacinth, lilac, geranium, jasmine, ylang-ylang, anise, clove, ginger, nutmeg, cardamom, cedar, cypress, vetiver, patchouli, labdanum, elderflower, and clary sage.

[0041] The fragrance composition of the present invention may contain, as a fragrance component, a base fragrance (fragrance composition) formulated to have a desired fragrance tone. The base fragrance is not particularly limited, but examples thereof include oriental-tone base fragrances, floral-tone base fragrances, herbal-tone base fragrances, citrus-tone base fragrances, green-tone base fragrances, aqua-tone base fragrances, fruit-tone base fragrances, woody-tone base fragrances, gourmand-tone base fragrances, powder-tone base fragrances, and base fragrances exhibiting two or more of these fragrance tones.

[0042] The fragrance composition of the present invention may take the form of a liquid preparation such as a solution in which the fragrance composition containing the present active ingredient is dissolved in a solvent, a heterogeneous liquid mixture in which the fragrance composition is mixed with water, or a dispersion in which the fragrance composition is dispersed in a solvent; a powder preparation; or other solid preparation (such as solid fat).

[0043] Examples of solvents for preparing the liquid preparation include water-soluble solvents and oil-soluble solvents. Examples of the solvent include water, ethanol, methanol, acetone, tetrahydrofuran, acetonitrile, 2-propanol, methyl ethyl ketone, glycerin, propylene glycol, dipropylene glycol, vegetable oils and fats, animal oils and fats, refined oils and fats (e.g., processed oils and fats such as medium-chain fatty acid triglycerides, and short-chain fatty acid triglycerides such as triacetin and tripropionin), various essential oils, triethyl citrate, isopropyl myristate, diethyl phthalate, diisobutyl adipate, diethylene glycol monobutyl ether, diethylene glycol monoethyl ether, dipropylene glycol monomethyl ether, and hexylene glycol. These solvents may be used alone or in combination.

[0044] The fragrance composition of the present invention is preferably in the form of a mixture of a fragrance composition containing the present active ingredient and water, or a dispersion of a fragrance composition containing the present active ingredient dispersed in water. Hereinafter, the mixture of a fragrance composition containing the present active ingredient and water and the dispersion of a fragrance composition containing the present active ingredient dispersed in water may be collectively referred to as "fragrance water."

[0045] As a dispersion in which a fragrance composition containing the present active ingredient is dispersed in water, a dispersion in which the fragrance composition is dispersed in a nonionic surfactant is more preferred. Examples of the nonionic surfactant include polyoxyalkylene-type and polyhydric alcohol-type surfactants. The polyoxyalkylene-type surfactants are nonionic surfactants having a polyoxyalkylene chain as the hydrophilic moiety. Examples of the polyoxyalkylene-type nonionic surfactants include polyoxyalkylene alkyl ethers, polyoxyalkylene alkylphenyl ethers, polyoxyalkylene alkylamino ethers, polyoxyalkylene fatty acid esters, polyoxyalkylene polyhydric alcohol fatty acid esters, polyoxyethylene / polyoxypropylene block polymers, polyoxyalkylene derivatives, and polyoxyethylene hydrogenated castor oil.

[0046] Examples of the polyoxyethylene alkyl ether include polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene myristyl ether, and polyoxyethylene octyldodecyl ether.

[0047] Examples of the polyoxyalkylene derivative include polyoxyethylene alkylene alkyl ether, polyoxyethylene distyrenated phenyl ether, and polyoxyethylene tribenzyl phenyl ether.

[0048] The polyoxyalkylene polyhydric alcohol fatty acid ester is a fatty acid ester in which a polyoxyalkylene chain is added to a polyhydric alcohol such as glycerin, polyglycerin, sorbitol, or sucrose, and examples thereof include polyoxyethylene glycerin fatty acid ester, polyoxyethylene polyglycerin fatty acid ester, polyoxyethylene sucrose fatty acid ester, and polyoxyethylene sorbitan fatty acid ester.

[0049] Examples of polyoxyethylene sorbitan fatty acid esters include polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan tristearate, polyoxyethylene sorbitan monooleate, polyoxyethylene sorbitan trioleate, and polyoxyethylene sorbitan triisostearate.

[0050] Examples of the polyhydric alcohol-based nonionic surfactant include polyhydric alcohol fatty acid esters, polyhydric alcohol alkyl ester ethers, and fatty acid dialkylol amides.

[0051] The polyhydric alcohol fatty acid ester is a fatty acid ester of a polyhydric alcohol such as glycerin, polyglycerin, sorbitol, or sucrose, and examples thereof include glycerin fatty acid ester, sorbitan fatty acid ester, and sucrose fatty acid ester.

[0052] Examples of sorbitan fatty acid esters include sorbitan monolaurate, sorbitan monopalmitate, and sorbitan monooleate.

[0053] Examples of glycerin fatty acid esters include glycerol monostearate and glycerol monooleate.

[0054] The lower limit of the HLB (Hydrophile Lypophile Balance) value of the nonionic surfactant is preferably 9.5, more preferably 10, and even more preferably 10.5, and the upper limit is preferably 15, more preferably 13, and even more preferably 12. If the HLB value is 9.5 or higher, the emulsification and dispersibility of the fragrance is good, and if it is 15 or lower, foaming of the aqueous dispersion of the fragrance due to the surfactant is suppressed. In the present invention, the HLB value is calculated using the following Griffin equation. HLB value = 20 × {(molecular weight of hydrophilic portion) / (total molecular weight)}

[0055] The aqueous dispersion preferably contains 0.1 to 1000 parts by mass, more preferably 1 to 300 parts by mass, and more preferably 7 to 80 parts by mass of a nonionic surfactant relative to 100 parts by mass of the fragrance composition. The lower limit of the content of the nonionic surfactant relative to 100 parts by mass of the fragrance composition is more preferably 10 parts by mass, and even more preferably 21 parts by mass, and the upper limit is preferably 70 parts by mass, and even more preferably 63 parts by mass. When the content of the nonionic surfactant is 7 parts by mass or more, the fragrance composition can be uniformly dispersed in water. Furthermore, by setting the content to 80 parts by mass or less, foaming of the aqueous dispersion due to the surfactant can be suppressed.

[0056] The concentration of the fragrance composition containing the active ingredient in the fragrance water is preferably 0.005% by mass, more preferably 0.01% by mass, and even more preferably 0.03% by mass as a lower limit, and is preferably 5% by mass, more preferably 3% by mass, and even more preferably 1% by mass as an upper limit.

[0057] By setting the concentration of the fragrance composition to 0.005% by mass or more, it is possible to impart a sufficient amount of fragrance to reduce unpleasant odors in articles, while by setting the concentration of the fragrance composition to 5% by mass or less, it is possible to reduce production costs and minimize the environmental impact of wastewater discharge.

[0058] The method for dispersing and emulsifying the fragrance composition is not particularly limited, and for example, the dispersion and emulsification treatment can be carried out using a homomixer, colloid mill, rotating disk homogenizer, high-pressure homogenizer, or the like.

[0059] (Method for reducing the odor of natural rubber) The method for reducing the odor of natural rubber of the present invention (hereinafter sometimes referred to as the "present odor reduction method") is characterized by using the present odor-reducing agent and / or the present fragrance composition. As will be shown in the examples below, the use of the present odor-reducing agent and / or the present fragrance composition can effectively reduce the odor of natural rubber.

[0060] The odor reduction method is preferably applied to natural rubber articles. In this specification, "natural rubber articles" refers to articles made from natural rubber, and includes both crosslinked and non-crosslinked natural rubber articles. Natural rubber is produced by nicking plants that produce natural rubber latex (milky liquid), recovering the latex, and coagulating the rubber component contained in the latex, and contains naturally occurring cis-1,4-polyisoprene.

[0061] Examples of plants that produce natural rubber latex include Hevea brasiliensis and Hevea brasiliensis of the Euphorbiaceae family, Rubber tree, Hevea brasiliensis, and Hevea lagos of the Moraceae family, Gum arabicum and Tragacanth of the Fabaceae family, Curculionidae, Zanzibar vine, Huntsumia elastica, and Urceola of the Asteraceae family, Guayule and the rubber dandelion, Gutta-percha, Balata and Sapodilla of the Sapotaceae family, Morning glory of the Asclepiadaceae family, and Eucommia of the Eucommiaaceae family.

[0062] The natural rubber article may further contain synthetic rubber in addition to natural rubber. Specific examples of the synthetic rubber include butyl rubber, isoprene rubber, polybutadiene rubber, styrene-butadiene rubber, chloroprene rubber, nitrile rubber such as acrylonitrile-butadiene rubber, hydrogenated nitrile rubber, norbornene rubber, ethylene-propylene rubber, ethylene-propylene-diene rubber, acrylic rubber, ethylene-acrylate rubber, fluororubber, chlorosulfonated polyethylene rubber, epichlorohydrin rubber, silicone rubber, urethane rubber, polysulfide rubber, phosphane rubber, and 1,2-polybutadiene. These may be used alone or in combination of two or more.

[0063] In the natural rubber article, the content of natural rubber in the rubber component is preferably 10% by mass or more, more preferably 30% by mass or more, even more preferably 50% by mass or more, particularly preferably 80% by mass or more, and most preferably 90% by mass or more, from the viewpoint of fully demonstrating the effect of the odor-reducing agent on reducing the natural rubber odor. The upper limit of the content of natural rubber in the rubber component in the natural rubber article is 100% by mass.

[0064] In the case of a product in which natural rubber is crosslinked, for example, a rubber component containing natural rubber is mixed with a co-crosslinking agent, a crosslinking initiator, an organic sulfur compound, etc., and crosslinked to form an article.

[0065] Specific examples of the natural rubber article are not particularly limited as long as it is made of natural rubber, and include, for example, gloves, rain shoes, shoe soles, rugs (e.g., mattresses, yoga mats, etc.), tires, conveyors, hoses, vibration damping materials, vibration isolating materials, toys, rubber bands, miscellaneous goods, stationery, bags, hair ties, etc., and among these, the odor reduction method of the present invention is suitably applicable to natural rubber gloves.

[0066] Examples of the odor reduction method include a method in which the odor-reducing agent and / or the fragrance composition are present in a space in which a natural rubber article is present, and a method in which the odor-reducing agent and / or the fragrance composition are attached to a natural rubber article.

[0067] Methods for attaching the present odor-reducing agent and / or the present fragrance composition to a natural rubber article include, for example, applying or spraying the present odor-reducing agent and / or the present fragrance composition to the natural rubber article, immersing the natural rubber article in the present odor-reducing agent and / or the present fragrance composition and drying it, and blending (mixing) the present odor-reducing agent and / or the present fragrance composition with raw materials and molding the natural rubber article.

[0068] In the odor reduction method of the present invention, it is preferable to immerse a natural rubber article (particularly a natural rubber glove) in fragranced water and then dry it to adhere the odor reducing agent and / or fragrance composition to the natural rubber article.

[0069] The time for which the natural rubber article is immersed in the fragranced water is not particularly limited, but the lower limit is preferably 5 minutes, more preferably 8 minutes, and even more preferably 10 minutes, and the upper limit is preferably 60 minutes, and more preferably 30 minutes.

[0070] The temperature of the fragrance water when the natural rubber article is immersed in the fragrance water is not particularly limited, but the lower limit is preferably 5°C, more preferably 8°C, and even more preferably 10°C, and the upper limit is preferably 80°C, more preferably 60°C, and even more preferably 50°C.

[0071] The odor reduction method of the present invention is achieved by removing a natural rubber article that has been immersed in scented water from the scented water and drying it.

[0072] The natural rubber article to which the perfume water is applied is preferably dried for 50 minutes or more and 240 minutes or less at a temperature of 30° C. to 90° C. Drying under these conditions allows drying while suppressing the volatilization of the perfume.

[0073] The present invention includes a natural rubber article comprising n-undecanal, 6-acetyl-1,1,2,4,4,7-hexamethyltetralin, and 2-methoxynaphthalene, and more preferably includes a natural rubber article having n-undecanal, 6-acetyl-1,1,2,4,4,7-hexamethyltetralin, and 2-methoxynaphthalene attached thereto. [Example]

[0074] The present invention will be described in detail below with reference to examples. However, the present invention is not limited to the following examples, and all modifications and embodiments that do not deviate from the spirit of the present invention are included within the scope of the present invention.

[0075] <Preparation of odor reducing agent> Odor reducing agents and fragrance compositions were prepared having the compositions shown in Table 1. Each active ingredient of the odor reducing agent was dissolved in the solvent component contained in the base fragrance, and the entire composition was in the form of a solution.

[0076] [Table 1]

[0077] The materials used in Table 1 are as follows: n-Undecanal: Tokyo Chemical Industry Co., Ltd. Tonalid (registered trademark) (6-acetyl-1,1,2,4,4,7-hexamethyltetralin): manufactured by Merck 2-Methoxynaphthalene: Tokyo Chemical Industry Co., Ltd. Floral base fragrance (ingredients: methyl dihydrojasmonate, α-hexylcinnamaldehyde, geraniol, etc.): Manufactured by Hasegawa Fragrance Co., Ltd. Oriental base fragrance (ingredients: sandal mysore core, vanillin, galaxolide, etc.): Manufactured by Hasegawa Fragrance Co., Ltd.

[0078] <Odor reduction test> The fragrance composition prepared above was dispersed in water using polyoxyethylene lauryl ether as a surfactant to obtain a 1% by weight (fragrance composition) aqueous dispersion (containing approximately 2% by weight of the surfactant). 0.1 g of this aqueous dispersion was impregnated into a circular filter paper (dimensions: 55 mm diameter). The scented filter paper and natural rubber gloves were sealed in a zip-lock bag (dimensions: 20 cm x 14 cm, material: polyethylene) and left for 10 minutes. After the zipper was opened, the odor of the air inside the bag was evaluated by three perfumers. A control sample, consisting of natural rubber gloves alone sealed in a zip-lock bag (without scented filter paper), was evaluated for odor in the air inside the bag in the same manner as above. The natural rubber odor and freshness of the fragrance were scored based on the evaluation criteria listed in Table 2. The evaluation results (average values ​​of the three experts) are also shown in Table 1.

[0079] [Table 2]

[0080] Examples 1 to 7 are fragrance compositions containing all three active ingredients, while Comparative Examples 1 to 6 are fragrance compositions containing none of the three active ingredients, or containing one or two of the three active ingredients.

[0081] It can be seen that in Examples 1 to 7, the natural rubber odor score was improved from 1 point (comparison product) to 3.7 points or more. On the other hand, in Comparative Examples 1 to 6, the natural rubber odor score was 2.7 points or less, indicating that the odor reduction effect was small. These results show that the odor reducer composed of a combination of three compounds, n-undecanal, 6-acetyl-1,1,2,4,4,7-hexamethyltetralin, and 2-methoxynaphthalene, has an extremely large effect of reducing the natural rubber odor.

[0082] It can be seen that in Examples 1 to 7, the freshness of the scent score improved from 1 point (comparison product) to 3.3 points or more. On the other hand, in Comparative Examples 1 to 6, the freshness of the scent score was 1.9 points or less, indicating that the scent was not refreshing. These results demonstrate that an odor-reducing agent comprising a combination of three compounds, n-undecanal, 6-acetyl-1,1,2,4,4,7-hexamethyltetralin, and 2-methoxynaphthalene, can impart a fresh scent to natural rubber articles.

[0083] <Fragrance test> 0.1 g of the fragrance composition shown in Table 3 was mixed with water and mixed with a medicine spoon to prepare a mixed solution with a fragrance composition concentration of 0.01% by mass. One pair of natural rubber gloves (Goodne, manufactured by Sumitomo Rubber Industries, Ltd.) was immersed in 1 L of this mixed solution (room temperature: approximately 10°C to 40°C) for 10 minutes. The natural rubber gloves were then removed from the mixed solution and dried in a dryer at 60°C for 50 minutes to prepare scented gloves with the fragrance composition attached. In addition, an accelerated test was conducted to promote the evaporation of the fragrance composition by heating the scented gloves and unscented gloves at 50°C for 8 hours.

[0084] [Table 3]

[0085] Seven general monitors evaluated the odor of the scented gloves immediately after production and after the accelerated test based on the evaluation criteria listed in Table 2. Natural rubber gloves without any fragrance treatment were used as a control. The evaluation results are also shown in Table 3. The natural rubber odor and freshness of the scent are shown as the average values ​​of the seven monitors.

[0086] Examples 8 and 9 are fragrance compositions containing all three active ingredients, while Comparative Examples 7 to 9 are fragrance compositions containing none of the three active ingredients, or containing one or two of the three active ingredients.

[0087] In Examples 8 and 9, evaluation after the accelerated test showed that the natural rubber odor score was improved from 1 point (comparison product) to 3.9 points or more. On the other hand, in Comparative Examples 7 to 9, the natural rubber odor score was 2.0 or less, indicating a small odor reduction effect. These results show that the odor reducer, which is a combination of n-undecanal, 6-acetyl-1,1,2,4,4,7-hexamethyltetralin, and 2-methoxynaphthalene, has an extremely large effect in reducing the natural rubber odor.

[0088] In Examples 8 and 9, evaluation after the accelerated test showed that the freshness of the scent score improved from 1 point (comparison product) to 4.0 points or more. On the other hand, in Comparative Examples 8 and 9, the freshness of the scent score was 1.7 points or less, indicating that the scent was not refreshing. These results demonstrate that an odor-reducing agent comprising a combination of three compounds, n-undecanal, 6-acetyl-1,1,2,4,4,7-hexamethyltetralin, and 2-methoxynaphthalene, can impart a fresh scent to natural rubber articles.

[0089] Furthermore, the results of accelerated testing showed that natural rubber gloves coated with an odor-reducing agent made from a combination of three substances - n-undecanal, 6-acetyl-1,1,2,4,4,7-hexamethyltetralin, and 2-methoxynaphthalene - maintained their natural rubber odor-reducing effect even after long-term storage, and retained their fresh scent. Maintaining a natural rubber odor-reducing effect over a long period of time is a major advantage for products that take several months from production to delivery to customers. [Industrial Applicability]

[0090] The present invention is useful for effectively reducing the natural rubber odor of natural rubber articles.

[0091] A preferred embodiment (1) of the present invention is an odor reducer for natural rubber, which comprises n-undecanal, 6-acetyl-1,1,2,4,4,7-hexamethyltetralin, and 2-methoxynaphthalene as active ingredients.

[0092] A preferred embodiment (2) of the present invention is a fragrance composition characterized by containing the natural rubber odor reducer of the above embodiment (1).

[0093] A preferred embodiment (3) of the present invention is a method for reducing the odor of natural rubber, characterized by using the odor-reducing agent according to embodiment (1) or the fragrance composition according to embodiment (2).

[0094] A preferred embodiment (4) of the present invention is a natural rubber article to which the odor-reducing agent according to embodiment (1) or the fragrance composition according to embodiment (2) is attached.

[0095] A preferred embodiment (5) of the present invention is the natural rubber article according to embodiment (4), which is a natural rubber glove.

Claims

1. An odor reducer for natural rubber, comprising n-undecanal, 6-acetyl-1,1,2,4,4,7-hexamethyltetralin, and 2-methoxynaphthalene as active ingredients.

2. A fragrance composition comprising the natural rubber odor-reducing agent according to claim 1.

3. A method for reducing the odor of natural rubber, comprising using the odor-reducing agent for natural rubber according to claim 1 or the fragrance composition according to claim 2.

4. A natural rubber article comprising n-undecanal, 6-acetyl-1,1,2,4,4,7-hexamethyltetralin, and 2-methoxynaphthalene.

5. 5. The natural rubber article according to claim 4, which is a natural rubber glove.

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