Liquid denture cleanser composition and method for cleaning dentures

Abstract

To provide a liquid denture cleanser composition having high cleaning power against color stains on dentures, excellent cleaning effect, good dispersibility, usability, and storage stability, and to provide a method for cleaning a denture using the composition.SOLUTION: Provided is a liquid denture cleanser composition comprises (A) a surfactant, (B) an organic phosphonic acid or salt thereof, and (C) a carboxymethylcellulose salt with an ether degree of 1.1 or higher and a pH of 7 to 9. Also provided is a method for cleaning a denture, comprising feeding the liquid denture cleanser composition and water into a cleaning tank of an ultrasonic denture cleaner and subsequently ultrasonically cleaning the denture.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a liquid denture cleanser composition which has high cleaning power against stains on dentures, excellent cleaning effect, and good dispersibility, ease of use and storage stability, and to a method for cleaning dentures using the same. [Background technology]

[0002] Stains that adhere to dentures (dentures and denture base) include denture plaque, food residue, stains (colored deposits), tartar, etc. Dentures, not only the teeth (dentures) but also the palate mucosa and gums (denture base) are made of resin and metal, so the area subject to staining is large and the stains are easily noticeable. In particular, the adhesion of stains to dentures is undesirable from the standpoint of hygiene and aesthetics, and the removal of stains is a major target for denture cleansers. However, it has been difficult to satisfactorily clean and remove colored stains such as stains that are firmly attached due to modification by foreign substances such as food in addition to salivary proteins.

[0003] Meanwhile, denture wearing patterns among partial denture wearers are becoming more diverse, and although the majority of people wear dentures during the day and remove them while sleeping, the number of 24-hour denture wearers who continue to wear dentures even while sleeping is also increasing. 24-hour denture wearers clean their dentures while removing them and brushing their teeth, and because they cannot soak their dentures in cleaning agents for long periods of time, as is the conventional cleaning method, are more likely to be dissatisfied with the current denture cleaning method and cleaning level than those who wear dentures only when necessary or only during the day.

[0004] Therefore, there has been a demand for cleaning using a "denture cleaner and a cleaning container (ultrasonic denture cleaner)" that allows thorough cleaning of denture stains easily and in a short time. Furthermore, in a cleaning method using this cleaning container, for example, a concentrated liquid denture cleaner is generally placed in the cleaning tank of the cleaning container, water is added, and then the denture is ultrasonically cleaned. In this case, it is assumed that the cleaner is automatically diluted during the ultrasonic cleaning process, so high dispersibility of the liquid denture cleaner is essential. On the other hand, considering that the cleaning tank of an ultrasonic denture cleaner is relatively small, with a diameter of about 10 cm, and that most users are elderly, it is easy to use a liquid denture cleaner that is easy to put into the cleaning tank without problems such as dripping, splashing, or over or under-putting. However, it has been difficult to achieve both such dispersibility and ease of use in putting into the cleaning tank, while also providing a cleaning power that satisfactorily cleans and removes stains from dentures.

[0005] To date, a concentrated liquid denture cleanser composition has been proposed that contains hydroxyethanediphosphonic acid, an alkylamine oxide, and benzoic acid or a derivative thereof, and has a pH of 5 to 6.5, and that has excellent stain-cleaning power and usability, as a denture cleanser particularly suitable for use in the cleaning container of an ultrasonic denture cleaner (Patent Document 1: JP 2018-90501 A). However, there is still room for improvement in terms of stain-cleaning power, and the cleaning power for darker stains is insufficient. In addition, there are issues with the usability deteriorating when the pH exceeds 6.5. Patent Document 2 (JP 2018-90499 A) proposes that a liquid denture cleanser composition containing hydroxyethanediphosphonic acid and a surfactant and having a pH of 5 to 9 has excellent cleaning power for stained stains, and has storage stability with suppressed phase separation even after low-temperature storage. Patent Document 2 does not focus on or consider usability, but there are issues with usability when the pH exceeds 6.5. Patent Document 3 (JP 2018-90500 A) proposes a concentrated liquid denture cleanser composition that contains a surfactant and a thickener and has a moderate viscosity (20 mPa s or more), and that has excellent stain-removing power, dispersibility, and usability. Patent Document 3 does not focus on or consider storage stability, but there are issues with storage stability at high temperatures. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2018-90501 A [Patent Document 2] JP 2018-90499 A [Patent Document 3] JP 2018-90500 A Summary of the Invention [Problem to be solved by the invention]

[0007] The present invention has been made in consideration of the above circumstances, and has an object to provide a liquid denture cleanser composition which has high cleaning power against denture stains, excellent cleaning effect, and good dispersibility, usability and storage stability, and a method for cleaning dentures using the same. [Means for solving the problem]

[0008] As a result of intensive research conducted by the present inventors to achieve the above object, it was found that when a liquid denture cleanser composition containing a surfactant and an organic phosphonic acid or a salt thereof is mixed with a carboxymethylcellulose salt having a specific degree of etherification or more and set at a pH of 7 to 9, a high cleaning power is exerted against stains on dentures (dentures and denture base; hereinafter, abbreviated as dentures), an excellent cleaning effect that removes even relatively dark stains can be imparted, and good usability and dispersibility can be achieved, and storage stability can also be imparted. Thus, according to the present invention, it was found that a liquid denture cleanser composition containing (A) a surfactant, (B) an organic phosphonic acid or a salt thereof, and (C) a carboxymethylcellulose salt having a degree of etherification of 1.1 or more and having a pH of 7 to 9 has a high cleaning power against stains on dentures, an excellent cleaning effect, and good dispersibility, usability, and storage stability, and thus the present invention was completed. Furthermore, since the above-mentioned liquid denture cleanser composition has the above-mentioned excellent properties, it can be made into a concentrated preparation, and further, since it has good dispersibility and ease of use even when automatically diluted during the ultrasonic cleaning treatment, it has been found that a method can be adopted in which the liquid denture cleanser composition and water are placed in the cleaning tank of an ultrasonic denture cleaner and then dentures are ultrasonically cleaned.

[0009] In the present invention, by combining the (A) and (B) components with the (C) carboxymethylcellulose salt having a degree of etherification of a specific value or more, and setting the pH of the composition within a specific range, it is possible to impart a remarkably high detergency that cleans and removes not only lightly colored stains but also relatively darkly colored stains. Moreover, the (C) component stably imparts a suitable viscosity, making it possible to achieve both good usability (ease of putting into a cleaning container) and dispersibility (ease of dispersing in water). Furthermore, unlike other thickeners, the (C) component can prevent the occurrence of sediment, turbidity, and precipitate over time even at a pH within the above-mentioned specific range, and can also make the liquid transparent, thereby imparting storage stability (appearance stability after high-temperature storage) that cannot be achieved when other thickeners are used. Therefore, the liquid denture cleanser composition of the present invention has good dispersibility, usability and storage stability, and can provide significantly high cleaning power against denture stains.As a result, it can also be used as a concentrated preparation that is diluted with water and used for ultrasonic cleaning using a cleaning container, such as an ultrasonic denture cleaner. In the present invention, the above-mentioned special effect can be imparted by the (C) component within a specific pH range. When the (C) component is combined with the (A) and (B) components at a pH of less than 7 or more than 9, the colored stain cleaning power is reduced. Furthermore, even if the pH is within the specific range, if the (C) component is not blended, the usability and storage stability are poor even if other thickening anionic water-soluble polymer compounds are further added, and the present effect is inferior. As shown in the comparative examples described later, Comparative Examples 4 and 5, in which the (C) component is blended at a pH of less than 7 or more than 9, had low cleaning power for deep colored stains. Furthermore, Comparative Examples 6 to 11, in which the (C) component is not blended, were inferior in usability (ease of putting into a cleaning container) and / or storage stability (appearance stability after high-temperature storage) even if sodium carboxymethylcellulose, sodium alginate, xanthan gum, sodium polyacrylate, or hydroxyethylcellulose with an inappropriate degree of etherification was added, even if the pH was within the specific range. In contrast, as shown in the Examples described later, a liquid denture cleanser composition containing the components (A), (B), and (C) of the present invention and having a pH of 7 to 9 had excellent cleaning power for light and dark stains, and also had good dispersibility (ease of dispersion in water), usability, and storage stability. In addition, the present invention can provide excellent cleaning power even without blending peroxides and the like that are generally used as denture cleansing agent components, and even when diluted with water. The cleaning effect is outstandingly excellent, removing stains that are firmly attached to dentures, that is, relatively dark stains such as stains that are strongly attached to a thin film called a pellicle formed on the denture surface mainly by saliva proteins and modified by foreign substances such as saliva or food in the oral cavity environment, and further, the stains can be thoroughly cleaned and removed not only from the teeth of dentures but also from denture bases made of resin or metal.

[0010] Accordingly, the present invention provides the following liquid denture cleanser composition and method for cleaning dentures. [1] (A) a surfactant, (B) Organic phosphonic acid or its salt and (C) Carboxymethylcellulose salt having a degree of etherification of 1.1 or more and having a pH of 7 to 9. [2] The liquid denture cleanser composition according to [1], wherein the surfactant (A) is one or more selected from anionic surfactants and amphoteric surfactants. [3] The liquid denture cleanser composition according to [2], wherein the anionic surfactant is selected from alkyl sulfates having 8 to 18 carbon atoms, α-olefin sulfonates having 8 to 18 carbon atoms, and acylamino acid salts having an acyl group with 8 to 18 carbon atoms, and the amphoteric surfactant is selected from alkylamine oxides having an alkyl group with 12 to 18 carbon atoms, and fatty acid amidopropyl betaines having an acyl group with 8 to 18 carbon atoms. [4] (B) The liquid denture cleanser composition according to any one of [1] to [3], wherein the organic phosphonic acid or a salt thereof is hydroxyethanediphosphonic acid or a salt thereof. [5] The liquid denture cleanser composition according to any one of [1] to [4], comprising 1 to 10% by mass of component (A) and 1 to 5% by mass of component (B). [6] The liquid denture cleanser composition according to any one of [1] to [5], comprising 0.1 to 0.5 mass % of component (C). [7] The liquid denture cleanser composition according to any one of [1] to [6], which has a viscosity at 25°C of 20 to 100 mPa·s. [8] The liquid denture cleanser composition according to any one of [1] to [7], which is a concentrated preparation to be diluted with water for use. [9] The liquid denture cleanser composition according to any one of [1] to [8], which is for ultrasonic cleaning.

[10] A method for cleaning dentures, comprising: charging a liquid denture cleanser composition according to any one of [1] to [9] and water into a cleaning tank of an ultrasonic denture cleaner, and then ultrasonically cleaning the dentures. Effect of the Invention

[0011] According to the present invention, it is possible to provide a liquid denture cleanser composition having high detergency against stains on dentures, excellent cleaning effect, and good dispersibility, usability, and storage stability, and a method for cleaning dentures using the same. The liquid denture cleanser composition of the present invention is prepared as a concentrated preparation that is diluted with water for use, and is effective for ultrasonic cleaning using a cleaning container. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] The present invention is described in further detail below. The liquid denture cleanser composition of the present invention is characterized by comprising (A) a surfactant, (B) an organic phosphonic acid or a salt thereof, and (C) a carboxymethylcellulose salt having a degree of etherification of 1.1 or more, and having a pH of 7 to 9.

[0013] As the surfactant (A), anionic surfactants, amphoteric surfactants, nonionic surfactants, and cationic surfactants can be used, but from the viewpoint of cleaning power for dark colored stains, anionic surfactants and amphoteric surfactants are preferred. More preferred surfactants are as described below, and from the viewpoint of cleaning power for dark colored stains, acylamino acid salts are particularly preferred as anionic surfactants, and alkylamine oxides are particularly preferred as amphoteric surfactants, and among these, those in which the carbon number of the acyl group or the alkyl group is 10 to 16 are preferred, such as sodium lauroyl glutamate and lauryl dimethylamine oxide. The surfactants may be used alone or in combination of two or more in terms of exerting the desired effect.

[0014] As the anionic surfactant, alkyl sulfates, α-olefin sulfonates, acylamino acid salts, and alkyl phosphates can be used. Among them, from the viewpoint of cleaning power for dark colored stains, alkyl sulfates having 8 to 18 carbon atoms, α-olefin sulfonates having 8 to 18 carbon atoms, and acylamino acid salts having 8 to 18 carbon atoms in the acyl group are preferred, and the above-mentioned acylamino acid salts are more preferred. As the salt, alkali metal salts such as sodium salts and potassium salts are preferred, and sodium salts are particularly preferred.

[0015] Examples of alkyl sulfates having 8 to 18 carbon atoms include lauryl sulfate and myristoyl sulfate, and lauryl sulfate is particularly preferred. Specifically, commercially available products such as sodium lauryl sulfate manufactured by Toho Chemical Industry Co., Ltd. or BASF can be used.

[0016] The carbon number of the α-olefin sulfonate is preferably 8 to 18, particularly 14 to 16. Among them, α-olefin sulfonate having 14 carbon atoms, particularly sodium salt (generic name: sodium tetradecene sulfonate) is preferred. Specifically, commercially available products usable for oral preparations, such as the trade names "K Liporan PJ-400CJ (powder)" and "Liporan LB-440 (liquid)" manufactured by Lion Specialty Chemicals Co., Ltd., can be used.

[0017] The acylamino acid salt has an acyl group with a carbon number of preferably 8 to 18, particularly 12 to 16, and includes acyl glutamate, acylaspartate, acylsarcosine salt, acyltaurine salt, etc. having such an acyl group with such a carbon number. Specific examples include acyl glutamate such as lauroyl glutamate and myristoyl glutamate, acylaspartate such as lauroyl aspartate, acylsarcosine salt such as lauroyl sarcosine salt, and acyltaurine salt such as lauroyl methyl taurine salt. Among them, acidic acylamino acid salts such as acyl glutamate and acylaspartate, particularly acyl glutamate, are preferred, and lauroyl glutamate is particularly preferred. As the salt, an alkali metal salt is preferred, and a sodium salt is particularly preferred. Specifically, a commercially available product manufactured by Asahi Kasei Chemicals Corporation can be used.

[0018] Examples of the amphoteric surfactant include alkylamine oxides and betaine-type amphoteric surfactants, and alkylamine oxides are particularly preferred. As the alkylamine oxide, an alkyldimethylamine oxide having preferably 12 to 18 carbon atoms, particularly 12 to 16 carbon atoms in the alkyl group can be used, for example, lauryl dimethylamine oxide. Specifically, as the lauryl dimethylamine oxide, a commercially available product such as "Kadenax DM12D-W" manufactured by Lion Specialty Chemicals Co., Ltd. can be used.

[0019] The betaine-type amphoteric surfactant is preferably one in which the carbon number of the acyl group is 8 to 18, particularly 8 to 12. Examples thereof include 2-alkyl-N-carboxymethyl-N-hydroxyethyl imidazolinium betaine, fatty acid amidopropyl betaines such as coconut oil fatty acid amidopropyl betaine and lauric acid amidopropyl betaine, and lauryl dimethylaminoacetic acid betaine, among which 2-alkyl-N-carboxymethyl-N-hydroxyethyl imidazolinium betaine and fatty acid amidopropyl betaine are preferred, and fatty acid amidopropyl betaine is particularly preferred. As the 2-alkyl-N-carboxymethyl-N-hydroxyethyl imidazolinium betaine, an aqueous solution of 2-coconut oil alkyl-N-carboxymethyl-N-hydroxyethyl imidazolinium betaine sodium sold by Lion Specialty Chemicals Co., Ltd. under the trade name "Enadicol C-40H" can be used. As the fatty acid amidopropyl betaine, a coconut oil fatty acid amidopropyl betaine sold by Degussa under the trade name "TEGO BETAIN CK" or a product sold by Sanyo Chemical Industries, Ltd. under the trade name "Revon 2000" can be used.

[0020] As the nonionic surfactant, polyethylene glycol type, particularly polyoxyethylene alkyl ether and polyoxyethylene hydrogenated castor oil are preferred. More preferably, polyoxyethylene alkyl ether having an alkyl group with 12 to 20 carbon atoms and an average added mole number of ethylene oxide (hereinafter abbreviated as EO added mole number) of 10 to 20 moles and / or polyoxyethylene hydrogenated castor oil having an EO added mole number of 5 to 60 moles can be used. Examples of polyoxyethylene alkyl ethers include those available under the trade names "EMALEX HC-60, EMALEX HC-100" (manufactured by Nippon Emulsion Co., Ltd.) and those available under the trade names "BLAUNON SR-705, 707" (manufactured by Aoki Oil & Fat Industries Co., Ltd.). Examples of polyoxyethylene hydrogenated castor oil include trade names "NIKKOL HCO-5, HCO-10, HCO-20, HCO-30" (manufactured by Nikko Chemicals Co., Ltd.) and trade name "Brownon RCW-20 OR" (manufactured by Aoki Oil & Fat Industries Co., Ltd.).

[0021] Examples of cationic surfactants include quaternary ammonium salts such as alkyl (having 6 to 20 carbon atoms) trimethylammonium salts, dialkyl (having 6 to 20 carbon atoms) dimethylammonium salts, and alkyl (having 6 to 20 carbon atoms) dimethylbenzylammonium salts; alkyl (having 6 to 20 carbon atoms) amine salts, alkyl (having 6 to 20 carbon atoms) amine ethylene oxide adducts, and alkyl (having 6 to 20 carbon atoms) pyridinium salts.

[0022] The blending amount of (A) surfactant is preferably 1 to 10% (mass%, hereinafter the same) of the entire composition, more preferably 3 to 10%. When the blending amount is 1% or more, sufficient cleaning power can be obtained even for dark stains. When the blending amount is 10% or less, sufficient and appropriate rinsing properties can be obtained, and stickiness after cleaning dentures and bitter taste when wearing dentures can be prevented.

[0023] (B) The organic phosphonic acid or salt thereof provides cleaning power against dark stains. Examples of organic phosphonic acids include hydroxyethanediphosphonic acid, ethylenediaminetetramethylenephosphonic acid, aminotrimethylenephosphonic acid, diethylenetriaminepentamethylenephosphonic acid, phosphonobutanetricarboxylic acid, nitrilotrismethylenephosphonic acid, and N,N,N',N'-tetrakis(phosphonomethyl)ethylenediamine. Among these, hydroxyethanediphosphonic acid is preferred because of its high cleaning power for dark colored stains. Examples of organic phosphonic acid salts include sodium salts, potassium salts, ammonium salts, magnesium salts, calcium salts, amine salts, and alkanolamine salts of the above organic phosphonic acids. The organic phosphonic acid or its salt may be a commercially available product such as hydroxyethanediphosphonic acid (trade name: Feriox 115-A) manufactured by Lion Specialty Chemicals Co., Ltd. or ethylenediaminetetramethylenephosphonic acid (trade name: N,N,N',N'-ethylenediaminetetrakis(methylenephosphonic acid)) manufactured by Tokyo Chemical Industry Co., Ltd.

[0024] The blending amount of (B) organic phosphonic acid or its salt is preferably 1 to 5% of the total composition, more preferably 3 to 5%. When the blending amount is 1% or more, sufficient cleaning power can be obtained even for deep colored stains. When the blending amount is 5% or less, sufficient storage stability can be ensured.

[0025] (C) Carboxymethylcellulose salt having a degree of etherification of 1.1 or more maintains excellent cleaning effect without reducing the cleaning power against colored stains caused by components (A) and (B), imparts appropriate viscosity, and acts to provide good usability and dispersibility. It also acts to ensure storage stability. The degree of etherification of the carboxymethylcellulose salt is 1.1 or more, preferably 1.1 to 1.9, and more preferably 1.3 to 1.5. When the degree of etherification is 1.1 or more, the storage stability is sufficiently ensured both at high temperature and at room temperature. When the degree of etherification is 1.9 or less, the dispersibility when diluted with water is good. In addition, the weight-average molecular weight of the carboxymethylcellulose salt is not particularly limited, but is preferably 1 million or more, and the viscosity of a 1% aqueous solution (25°C) is preferably 1,500 to 2,000 mPa·s. The viscosity of a 1% aqueous solution (25°C) is a value measured using a B-type viscometer. As such a carboxymethylcellulose salt having a specific degree of etherification, for example, a commercially available product such as sodium carboxymethylcellulose having the above-mentioned degree of etherification manufactured by Daicel Millize Co., Ltd. can be used.

[0026] The blending amount of the (C) component is preferably 0.1 to 0.5% of the total composition, more preferably 0.2 to 0.4%. When the blending amount is 0.1% or more, a suitable viscosity is imparted, good usability is ensured, and the liquid is sufficiently prevented from jumping out of the container or splashing when poured into the cleaning tank. When the blending amount is 0.5% or less, a suitable viscosity is maintained, and good usability is sufficiently maintained. When the blending amount is more than 0.5%, the viscosity becomes too high, and usability becomes poor, and it may take a long time to pour into the cleaning tank or require a strong pressure to be applied to the bottom of the container, resulting in poor usability.

[0027] In addition to the above-mentioned components, the liquid denture cleanser composition of the present invention may contain other known components, such as fragrances, solvents, colorants, and disinfectants, if necessary.

[0028] Examples of the fragrance include natural fragrances such as spearmint oil, peppermint oil, anise oil, eucalyptus oil, wintergreen oil, cassia oil, clove oil, thyme oil, sage oil, lemon oil, orange oil, peppermint oil, cardamom oil, coriander oil, mandarin oil, lime oil, lavender oil, rosemary oil, laurel oil, chamomile oil, caraway oil, marjoram oil, bay oil, lemongrass oil, origanum oil, pine needle oil, and cinnamon bark oil, as well as menthol, menthone, carvone, ethyl butyrate, vanillin, ethyl maltol, anethole, methyl salicylate, cinnamic aldehyde, cineole, eugenol, ethyl vanillin, maltose, and the like.

[0043] Conventional flavors that can be used in oral preparations include single flavors such as ethyl acetate, limonene, citronellol, linalool, linalyl acetate, menthyl acetate, pinene, octyl aldehyde, citral, pulegone, carbyl acetate, anisaldehyde, ginger oleoresin, creosol, and dl-camphor, as well as single flavors such as ethyl acetate, allyl cyclohexane propionate, methyl anthranilate, ethyl methylphenyl glycidate, undecalactone, hexanal, ethyl alcohol, propyl alcohol, butanol, and isoamyl alcohol, and / or various compound flavors including natural flavors, in normal amounts.

[0029] As the solvent, water (ion-exchanged water) is usually used, but polyhydric alcohol or the like can also be added at about 5 to 20%.

[0030] Examples of colorants include legal dyes such as Red No. 2, Red No. 3, Red No. 225, Red No. 226, Yellow No. 4, Yellow No. 5, Yellow No. 205, Blue No. 1, Blue No. 2, Blue No. 201, Blue No. 204, and Green No. 3, caramel color, safflower color, gardenia color, cochineal color, annatto color, titanium mica, and titanium oxide.

[0031] The bactericide may be a non-ionic bactericide such as isopropyl methylphenol, etc. The amount of the bactericide to be used is an effective amount within a range that does not impair the effects of the present invention. In the present invention, it is preferable not to use (0% blend amount) oxidizing agents and bleaching agents, such as peroxides such as sodium percarbonate and sodium perborate, hypochlorous acid or its salts, and sulfites, which are generally used as denture cleansing agent components, particularly from the viewpoint of preventing deterioration of dentures. If they are used, the blend amount of each is preferably 0.03% or less, and more preferably 0.01% or less.

[0032] The liquid denture cleanser composition of the present invention has a pH (25° C.) of 7 to 9, preferably 7.5 to 8.5. If the pH is less than 7, the cleaning power for dark stains is reduced, and the cleaning power for stains is inferior, whereas if the pH exceeds 9, the composition becomes alkaline, raising safety concerns when it comes into contact with hands or oral mucosa. The pH may be adjusted as it comes, or may be adjusted by adding a pH adjuster, such as sodium hydroxide, potassium hydroxide, hydrochloric acid, phosphoric acid or a salt thereof, citric acid or a salt thereof, sodium carbonate, sodium hydrogen carbonate, boric acid or a salt thereof, etc.

[0033] In particular, from the viewpoint of usability, the liquid denture cleanser composition preferably has a viscosity of 20 to 100 mPa·s, more preferably 25 to 80 mPa·s, and even more preferably 25 to 70 mPa·s, which is also preferable in terms of dispersibility. The above-mentioned viscosity ranges can achieve both better usability (ease of putting into a cleaning container) and dispersibility (ease of dispersing in water). If the viscosity is less than 20 mPa·s, the viscosity is too low and the liquid may jump out of the container or splash when put into a cleaning tank, resulting in poor usability. If the viscosity exceeds 100 mPa·s, the viscosity is too high and it may take a long time to put into the cleaning tank or it may be necessary to press the container strongly, resulting in poor usability. The viscosity was measured by the following method. B-type viscometer: VISCOMETER TVB-10 (manufactured by Toki Sangyo Co., Ltd.) Rotor No.: M1 Rotation speed: 60 rpm Measurement time: 60 seconds Measurement temperature: 25℃

[0034] The liquid denture cleanser composition can be prepared by a conventional method, for example, by placing each component in a 5 L kettle and stirring and mixing with a three-one motor.

[0035] The liquid denture cleanser composition of the present invention can be used in a normal manner, and can be used as is without diluting the liquid denture cleanser composition, but is preferably a concentrated preparation (concentrated liquid denture cleanser composition) that is applied by immersing dentures in a diluted cleanser solution diluted with water at the time of use, and can be prepared as a concentrated denture cleanser. After immersion and cleaning, it can be used by rinsing with water as necessary. In the case of a concentrated liquid denture cleanser composition, the preferred dilution ratio with water is 10 to 100 times, particularly 10 to 50 times, in terms of usability and solubility. For example, a concentrated preparation is prepared in which the concentration of component (A) in the preparation is 10% or less, the concentration of component (B) is 5% or less, and the concentration of component (C) is 0.5% or less, particularly 0.4% or less, and when used, the diluted cleanser solution after dilution can be designed so that the concentration of component (A) is 0.1% or more, the concentration of component (B) is 0.1% or more, and the concentration of component (C) is 0.01% or more. The pH (25°C) of the diluted cleanser solution is 7 to 9, preferably 7.5 to 8.5. It is more preferable to design the amount and pH of each component in the concentrated preparation so that all of these are within the above range, and to appropriately set the dilution ratio.

[0036] The liquid denture cleanser composition of the present invention can be suitably used as a concentrated preparation (concentrated liquid denture cleanser composition) in a denture cleaner together with water for dilution, and then a cleaning method in which dentures are immersed in the composition can be suitably adopted. Specifically, the liquid denture cleanser composition and water can be poured into a cleaning tank of a denture cleaner, preferably an ultrasonic denture cleaner, for dilution, and then dentures can be immersed in the diluted cleaner for cleaning. When an ultrasonic denture cleaner is used, dilution is automatically performed during the ultrasonic cleaning process. In this case, the denture cleaner may be one equipped with a cleaning tank in which the liquid preparation can be poured and the dentures immersed therein for cleaning, and a known one may be used. The cleaning tank of the denture cleaner is not particularly limited as long as it is a size suitable for holding full or partial dentures, but a compact one is preferable because of ease of use (location). Specifically, a denture cleaner having a cleaning tank in the shape of a circle or ellipse with a diameter or major axis of 12 cm or less, or a square with at least one side of 12 cm or less is preferable from the viewpoint of usability because it is easy to pour the concentrated liquid denture cleaner composition into it. The capacity of the cleaning tank is preferably about 100 to 150 mL. Furthermore, in terms of cleaning effect and efficiency, the denture cleaner is preferably equipped with an ultrasonic device, and an ultrasonic denture cleaner is suitable. The ultrasonic cleaning frequency is preferably 25 to 120 kHz, more preferably 40 to 100 kHz. If the ultrasonic frequency is equal to or higher than the lower limit, the sound during cleaning is small, and cleaning can be performed without causing harm to the denture, such as deformation or cracking. If the ultrasonic frequency is equal to or lower than the upper limit, high cleaning power can be obtained. Furthermore, the output is preferably 5 to 200 W, more preferably 10 to 100 W. If the ultrasonic output is equal to or higher than the lower limit, high cleaning power can be obtained. If the ultrasonic output is equal to or lower than the upper limit, cleaning can be performed without causing harm to the denture, such as deformation or cracking.

[0037] In addition, when cleaning dentures using the above-mentioned denture cleaner, the denture is immersed for 1 minute or more, preferably 3 minutes or more, and 15 minutes or less, preferably 7 minutes or less. The optimal immersion time is about 5 minutes (4 to 6 minutes). Denture stains can be removed more efficiently by using ultrasonic cleaning or the like. It is even more effective to clean the dentures using the liquid denture cleaner composition of the present invention after lightly removing stains with a toothbrush or the like. EXAMPLES

[0038] The present invention will be described in detail below with reference to examples and comparative examples, but the present invention is not limited to the following examples. In the following examples, % indicates % by mass unless otherwise specified.

[0039] [Examples and Comparative Examples] Liquid denture cleanser compositions (concentrated preparations) having the compositions shown in Tables 1 to 3 were prepared by the following method, and these were used as test samples and evaluated by the following methods. The results are also shown in the tables.

[0040] Preparation method: The ingredients shown in the table were placed in a 5L kettle and mixed with stirring using a three-one motor.

[0041] (1) Usability evaluation method The evaluation was carried out by a sensory test using 10 evaluators. Each of the liquid denture cleanser compositions for the test samples was further added with 0.001% Blue No. 1 to give it a blue color, and 250 mL of the sample was filled into a 250 mL PET container and sealed with a hinge cap (diameter: 2 mm). The container was held in one hand and about 5 g was poured into a denture cleanser container with a diameter of 7.5 cm and a depth of 5 cm. The ease of pouring was evaluated according to the following rating criteria. Here, ease of pouring means that the desired amount can be poured accurately and easily into the cleaning tank without splashing or spilling out of the container when poured into the cleaning tank, without soiling the area around the cleaning tank. Scoring criteria 4 points: Very easy to insert 3 points: Somewhat easy to insert 2 points: Somewhat difficult to insert 1 point: Very difficult to insert The ease of insertion ratings of the 10 people were averaged and the usability was evaluated according to the following criteria. Evaluation criteria ◎: 3.5 points or more and 4.0 points or less ○: 3.0 points or more and less than 3.5 points △: 2.0 points or more and less than 3.0 points ×: Less than 2.0 points

[0042] (2) Method for evaluating dispersibility Each of the liquid denture cleaner compositions of the test samples was further added with 0.001% Blue No. 1 to give it a blue color, which was used as a sample. 5 g of the blue-colored sample was poured into the cleaning tank of an ultrasonic denture cleaner, and 130 mL of cold water stored at 0°C was poured in, and ultrasonic cleaning was started. 5 minutes after the start, 1 mL of cleaning solution was collected from a point 4 cm from the center of the edge of the cleaning tank and 1.5 cm deep from the liquid surface, and the absorbance (630 nm) of the diluted cleaner was measured (A1). The absorbance was measured when the sample was completely dissolved (A0), and the dispersion rate was calculated using the following formula (1). From the calculated dispersion rate, the dispersibility was evaluated according to the following evaluation criteria. Formula (1); Dispersion rate (%)=(A1 / A0)×100 Evaluation criteria ◎: Dispersion rate after ultrasonic cleaning (5 minutes) is 100% ○: Dispersion rate after ultrasonic cleaning treatment (5 minutes) is 90% or more but less than 100% △: Dispersion rate after ultrasonic cleaning treatment (5 minutes) is 80% or more but less than 90% ×: Dispersion rate after ultrasonic cleaning treatment (5 minutes) is less than 80%.

[0043] (3) Evaluation method for colored stain cleaning power (3-1) Method for evaluating cleaning power for lightly colored stains (i) Method for preparing acrylic plate with iron-tannin stain 50 g of Japanese tea (Itoen), 5 bags of black tea (Lipton Brisk teabags), and 12 g of instant coffee (Nescafe) were added to 1,200 mL of boiled ion-exchanged water and left overnight. The Japanese tea and black tea were then removed by filtration to prepare a tannin extract. The surface of the acrylic plate (Kuraray Co., Ltd., 10 mm long x 10 mm wide x 5 mm thick) was treated by sandblasting, and then placed in an ultrasonic denture cleaner (product name: ultrasonic cleaner AU-80C, Aiwa Medical Industry Co., Ltd.) containing neutral detergent for 5 minutes, and then rinsed with water. After repeating the cleaning process with the ultrasonic denture cleaner three times, the plate was naturally dried, and the Lab value (L0) of the acrylic plate before the adhesion of tannin iron stain was measured. The above acrylic plate was repeatedly immersed in 0.5% albumin aqueous solution → tannin extract solution → 0.6% ammonium iron (III) citrate aqueous solution for 30 minutes each, 10 times, air-dried at room temperature for 1 day, washed with running water, and air-dried again to prepare an acrylic plate with tannin iron stain. The surface color of the prepared acrylic plate with tannin iron stain was measured, and the value was taken as the Lab value (L1). The mean L1 value was 45 (range 40-49). (ii) Method for evaluating the effect of removing tannin-iron stains 6.5 g of the liquid denture cleaner composition of the test sample was diluted 20 times with ion-exchanged water to obtain 130 mL of each diluted cleaner solution, which was poured into the cleaning tank of an ultrasonic denture cleaner, and the acrylic plate with tannin iron stains prepared in (i) above was immersed in the solution and subjected to ultrasonic cleaning treatment (frequency: 42 kHz, output: 17 W) for 5 minutes. After the ultrasonic cleaning treatment, the acrylic plate was rinsed under running water and dried, after which the Lab value (L2) of the plate was measured. The tannin iron stain removal rate was calculated using the following formula (2). Formula (2); Tannin iron stain removal rate (%) = [(L1-L2) / (L1-L0)] x 100 From the calculated tannin-iron stain removal rate, the cleaning power for lightly colored stains was evaluated according to the following evaluation criteria. Evaluation criteria ◎: Tannin iron stain removal rate 70% or more ○: Tannin iron stain removal rate is 50% or more but less than 70% △: Tannin iron stain removal rate is 30% or more but less than 50% ×: Less than 30% of tannin iron stains removed

[0044] (3-2) Method for evaluating cleaning power for dark stains (i) Method for preparing acrylic plate with iron-tannin stain 50 g of Japanese tea (Itoen), 5 bags of black tea (Lipton Brisk teabags), and 12 g of instant coffee (Nescafe) were added to 1,200 mL of boiled ion-exchanged water and left overnight. The Japanese tea and black tea were then removed by filtration to prepare a tannin extract. The surface of the acrylic plate (Kuraray Co., Ltd., 10 mm long x 10 mm wide x 5 mm thick) was treated by sandblasting, and then placed in an ultrasonic denture cleaner (product name: ultrasonic cleaner AU-80C, Aiwa Medical Industry Co., Ltd.) containing neutral detergent for 5 minutes, and then rinsed with water. After repeating the cleaning process with the ultrasonic denture cleaner three times, the plate was naturally dried, and the Lab value (L0) of the acrylic plate before the adhesion of tannin iron stain was measured. The above acrylic plate was repeatedly immersed in 0.5% albumin aqueous solution → tannin extract solution → 0.6% ammonium iron (III) citrate aqueous solution for 30 minutes each, 20 times, and then air-dried at room temperature for one day, washed with running water, and air-dried again to prepare an acrylic plate with tannin iron stain. The color of the surface of the prepared acrylic plate with tannin iron stain was measured, and the value was taken as the Lab value (L1). The mean L1 value was 30 (range 20-39). (ii) Method for evaluating the effect of removing tannin-iron stains 6.5 g of the liquid denture cleaner composition of the test sample was diluted 20 times with ion-exchanged water to obtain 130 mL of each diluted cleaner solution, which was poured into the cleaning tank of an ultrasonic denture cleaner, and the acrylic plate with tannin iron stains prepared in (i) above was immersed in the solution and subjected to ultrasonic cleaning treatment (frequency: 42 kHz, output: 17 W) for 5 minutes. After the ultrasonic cleaning treatment, the acrylic plate was rinsed under running water and dried, after which the Lab value (L2) of the plate was measured. The tannin iron stain removal rate was calculated using the following formula (2). Formula (2); Tannin iron stain removal rate (%) = [(L1-L2) / (L1-L0)] x 100 From the calculated tannin-iron stain removal rate, the cleaning power for dark colored stains was evaluated according to the following evaluation criteria. Evaluation criteria ◎: Tannin iron stain removal rate 70% or more ○: Tannin iron stain removal rate is 50% or more but less than 70% △: Tannin iron stain removal rate is 30% or more but less than 50% ×: Less than 30% of tannin iron stains removed

[0045] (4) Evaluation method for storage stability A 100 mL glass screw tube was filled with 80 mL of the liquid denture cleanser composition as a test sample and stored in a high temperature (50°C) constant temperature bath, a high temperature (40°C) constant temperature bath, or at room temperature (RT) for one month. The change in appearance after storage under each condition (compared to the initial appearance of the product immediately after filling) was visually observed, and the storage stability was evaluated according to the following evaluation criteria. The initial appearance of the product immediately after filling was a transparent liquid without any foreign matter. Evaluation criteria ◎: No difference from the initial product, no sediment, turbidity or precipitate observed under all storage conditions ○: Almost no sediment or turbidity was observed under all storage conditions. △: Sediment or turbidity was observed under any storage conditions. ×: Precipitation was observed under any storage conditions.

[0046] Details of the main raw materials used are shown below. Component (A) Lauryl dimethylamine oxide: Manufactured by Lion Specialty Chemicals Co., Ltd. (Product name: Cadenax DM12D-W) Sodium Lauroyl Glutamate: Asahi Kasei Chemicals Corporation (Product name: AminoSurfact ALMS-P1) Sodium α-olefin sulfonate: Manufactured by Lion Specialty Chemicals Co., Ltd. (Product name: Liporan LB-440) Sodium Lauryl Sulfate: BASF (product name: Texapon OC-P) Coconut oil fatty acid amidopropyl betaine (30% aqueous solution): Sanyo Chemical Industries, Ltd. (Product name: Levon 2000) (B) Component Hydroxyethanediphosphonic acid: Manufactured by Lion Specialty Chemicals Co., Ltd. (Product name: Feriox 115-A) Ethylenediaminetetramethylenephosphonic acid: Manufactured by Tokyo Chemical Industry Co., Ltd. (Product name: N,N,N',N'-ethylenediaminetetrakis(methylenephosphonic acid)) (C) Component Sodium Carboxymethylcellulose: Manufactured by Daicel Miraize Co., Ltd. CMC-1 (Etherification degree: 1.10) CMC-2 (Etherification degree: 1.30) CMC-3 (Etherification degree: 1.50) CMC-4 (Etherification degree: 0.90) (Comparison product) Other Ingredients Sodium alginate: Kimika Co., Ltd. (Product name: Kimika Algin) (Comparison product) Xanthan gum: CP Kelco (product name: Monart Gum DA) (comparison product) Sodium polyacrylate: Manufactured by Toagosei Co., Ltd. (Product name: Rheosic 260H) (comparison product) Hydroxyethylcellulose: Manufactured by Daicel Miraize Co., Ltd. (Product name: HEC Daicel) (Comparison product)

[0047] The viscosity of each liquid denture cleanser composition shown in the table was measured by the following method. B-type viscometer: VISCOMETER TVB-10 (manufactured by Toki Sangyo Co., Ltd.) Rotor No.: M1 Rotation speed: 60 rpm Measurement time: 60 seconds Measurement temperature: 25℃

[0048] [Table 1]

[0049]

Table 2

[0050]

Table 3

Claims

1. (A) a surfactant, (B) Organic phosphonic acid or its salt and (C) A liquid denture cleanser composition comprising 0.1 to 0.5% by mass of a carboxymethylcellulose salt having a degree of etherification of 1.1 to 1.5 and having a pH of 7 to 9.

2. 2. The liquid denture cleanser composition according to claim 1, wherein the surfactant (A) is one or more surfactants selected from the group consisting of anionic surfactants and amphoteric surfactants.

3. 3. The liquid denture cleanser composition according to claim 2, wherein the anionic surfactant is selected from alkyl sulfates having 8 to 18 carbon atoms, α-olefin sulfonates having 8 to 18 carbon atoms, and acylamino acid salts having an acyl group with 8 to 18 carbon atoms, and the amphoteric surfactant is selected from alkylamine oxides having an alkyl group with 12 to 18 carbon atoms, and fatty acid amidopropyl betaines having an acyl group with 8 to 18 carbon atoms.

4. 4. The liquid denture cleanser composition according to claim 1, wherein the organic phosphonic acid or its salt (B) is hydroxyethanediphosphonic acid or its salt.

5. 5. The liquid denture cleanser composition according to any one of claims 1 to 4, comprising 1 to 10% by mass of component (A) and 1 to 5% by mass of component (B).

6. A liquid denture cleanser composition described in any one of claims 1 to 5, wherein component (C) is a carboxymethylcellulose salt having a degree of etherification of 1.3 to 1.5, and the amount thereof is 0.2 to 0.4 mass%.

7. The liquid denture cleanser composition according to any one of claims 1 to 6, which has a viscosity at 25°C of 20 to 100 mPa·s.

8. The liquid denture cleanser composition according to any one of claims 1 to 7, which is a concentrated preparation for use by diluting with water.

9. The liquid denture cleanser composition according to any one of claims 1 to 8, which is used for ultrasonic cleaning.

10. A method for cleaning dentures, comprising: charging a liquid denture cleanser composition according to any one of claims 1 to 9 and water into a cleaning tank of an ultrasonic denture cleaner, and then ultrasonically cleaning the dentures.

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