Detergent composition for automatic dishwashers

Abstract

To provide a detergent composition for an automatic dishwashing machine and a dishwashing method with which it is possible to effectively wash protein-containing stains, such as thermal-denatured yolk stains, even when the repeated use of washing liquid causes its liquid properties to change into neutral to weakly alkaline regions.SOLUTION: A detergent composition for an automatic dishwashing machine contains component (a), component (b), and water, with the pH at 25°C being more than 11 or more and 14 or less. Component (a): a reductant with a redox potential of +71 mV or less. Component (b): a hydroxide of alkali metal.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a detergent composition for automatic dishwashers and a method for cleaning dishes. [Background technology]

[0002] Dishwashers are used to wash dirty dishes, glasses, cooking utensils, and other tableware in kitchens such as homes, restaurants, and coffee shops, as well as plastic containers for ingredients and products used in food and beverage factories. The main target stains are food-derived proteins, starches, oils, and grease, which combine to adhere to dishes, glasses, cooking utensils, and other tableware and plastic containers. In addition, these stains can be thermally denatured during cooking, turning into strong, adherent stains.

[0003] Typically, dishwashers perform washing in the order of washing and rinsing. The time required for these processes is very short, with the washing process taking approximately 40 to 180 seconds and the rinsing process taking approximately 5 to 20 seconds, according to the process design for commercial use. However, for stubborn stains, these designed times may not be sufficient for cleaning, and it is not uncommon for the washing process to take several times longer than the designed time to achieve adequate cleaning.

[0004] Patent Document 1 discloses a throat depressant for use in cleansers, and a cleanser composition containing the throat depressant, which contains a chelating agent or the like as a main cleansing ingredient, and also contains carbonate and / or percarbonate and an organic acid including at least one of succinic acid, fumaric acid, citric acid, and malic acid, and is to be contained in a solid or powdered cleanser that generates carbon dioxide gas when brought into contact with water or the like and used, and which contains a surfactant that generates foam during use as an active ingredient. Patent Document 2 discloses a liquid detergent composition containing a) an alkanolamine, b) a sulfite, c) a perfume oil containing an aldehyde or a ketone, and d) a sulfur-containing pro-perfume compound, which provides improved stability and perfume longevity. Patent Document 3 discloses a high-bulk-density granular detergent composition that contains 3.1 to 10% by weight of sulfite, 1 to 30% by weight of nonionic surfactant, and 0.01% by weight or more of fragrance, and has a bulk density of 0.6 g / ml or more, thereby maintaining good stability of the fragrance from the fragrance even over a long period of time. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-3899 [Patent Document 2] Special Publication No. 2016-522279 [Patent Document 3] Japanese Patent Application Publication No. 9-78099 Summary of the Invention [Problem to be solved by the invention]

[0006] Various types of stains adhere to dishes, but protein-containing stains in particular are prone to deterioration and solidification, making them difficult to remove in a short time using a commercial dishwasher. In particular, egg yolk and other stains can adhere strongly depending on the state of deterioration of the stain due to drying, denaturation, etc. over time after adhesion, making them even more difficult to remove in a short time. In order to effectively remove protein-containing stains in a short time, currently, strong alkaline conditions are unavoidable. However, in commercial dishwashers, the cleaning solution used to wash dishes is usually reused, and as a result, the solution becomes mixed with dirt and is diluted with rinse water, resulting in a neutral to weakly alkaline range of liquid pH. In this case, protein-containing stains become difficult to remove, which poses a problem.

[0007] The present invention provides a dishwasher detergent composition and a method for washing dishes, which can effectively clean protein-containing stains, such as heat-denatured egg yolk stains, even when the liquid pH is changed to a neutral to weakly alkaline range by reusing the washing liquid in an automatic dishwasher, and which has little reduction in detergency due to pH fluctuations. [Means for solving the problem]

[0008] The present invention relates to a detergent composition for automatic dishwashers, which contains the following components (a) and (b), and water, and has a pH at 25°C of more than 11 and 14 or less: (a) Component: a reducing agent with an oxidation-reduction potential of +71 mV or less (b) Component: Alkali metal hydroxide

[0009] The present invention also relates to a method for washing tableware, which comprises using an automatic dishwasher to wash tableware stained with protein using a cleaning liquid prepared by diluting the detergent composition for automatic dishwashers of the present invention with water. [Effects of the Invention]

[0010] According to the present invention, there are provided a dishwasher detergent composition and a method for washing dishes that can effectively clean protein-containing stains, such as heat-denatured egg yolk stains, even when the liquid pH is changed to a neutral to weakly alkaline range by reusing the washing liquid in an automatic dishwasher, and that exhibits little decrease in detergency due to pH fluctuations. DETAILED DESCRIPTION OF THE INVENTION

[0011] The dishwasher detergent composition and dishwashing method of the present invention can effectively clean protein-containing stains, such as heat-denatured egg yolk stains, even when the liquid pH is in the neutral to weakly alkaline range due to reuse of the cleaning liquid in an automatic dishwasher, and the reason for little reduction in detergency due to pH fluctuations is not entirely clear, but is presumed to be as follows. The removal of food stains using a cleaning solution containing an alkaline agent is achieved by hydrolyzing proteins and solubilizing and dispersing them through the negative charges of amino acid residues in the case of protein stains, by hydrolyzing fats and oils to form fatty acid soaps that are solubilized and dispersed in the case of lipid stains, and by hydrolyzing starch to shorten the molecules that are solubilized and dispersed in the case of starch stains. However, in actual cleaning using a commercial automatic dishwasher, the cleaning solution containing some of the solubilized stains during the wash is recovered and reused. Although the initial cleaning solution is highly alkaline and exhibits good cleaning performance, as the cleaning solution is recovered, the pH of the cleaning solution decreases due to soluble acidic compounds such as fatty acids and amino acids. In the neutral to weakly alkaline range of such recovered cleaning solution, the cleaning effect on food stains is reduced, and the cleaning performance of proteins in particular is significantly reduced. Many proteins contain disulfide bonds that stabilize their structure, but in the present invention, the specific reducing agent (component (a)) cleaves the disulfide bonds of proteins, solubilizing and dispersing the proteins when the pH of the recovered washing solution is in the neutral to weakly alkaline range, which is believed to be why cleaning power can be maintained regardless of pH. The reducing agent of the present invention, if it has a redox potential of disulfide bonds of +71 mV or less, is believed to be able to cleave disulfide bonds even when the pH of the washing solution is lowered by recovery in an automatic dishwasher and even during short wash periods, thereby achieving high cleaning effectiveness and maintaining cleaning power. However, the effects of the present invention are not limited to the mechanism of action shown here.

[0012] [Detergent composition for automatic dishwashers] <Component (a)> Component (a) is a reducing agent having an oxidation-reduction potential of +71 mV or less. From the viewpoint of protein cleansing ability and maintaining protein cleansing power when the pH changes from neutral to weakly alkaline (hereinafter referred to as "maintaining protein cleansing ability"), the redox potential of component (a) is +71 mV or less, preferably +60 mV or less, more preferably +55 mV or less, and even more preferably +50 mV or less. The lower the lower limit of the redox potential of component (a), the greater the expected effect, and although there are no particular limitations, from the viewpoint of ease of availability, it is preferably 0 mV or more, more preferably 3 mV or more. The redox potential of component (a) is measured by the following method. Distilled water is added to component (a) to a concentration of 0.016 mol / L, and 1 mol / L of hydrochloric acid and / or sodium hydroxide is added to adjust the pH to 7.5 to prepare a prepared solution. The temperature of the prepared solution is adjusted to 60°C, and the redox potential is measured using a redox potentiometer (for example, an ORP meter (ORP5 Pen ORP Meter) manufactured by Cem Corporation).

[0013] Component (a) is specifically one or more selected from sulfites, disulfates, thiosulfates, and iodides, and specifically includes one or more selected from sodium sulfite (+50 mV), potassium sulfite (+50 mV), sodium disulfate (+17 mV), potassium disulfate (+17 mV), potassium iodide (+28 mV), sodium iodide (+28 mV), sodium thiosulfate (+5 mV), and potassium thiosulfate (+5 mV). Component (a) is not particularly limited as long as it has a redox potential of +71 mV or less. From the viewpoints of protein cleaning ability and ease of availability, however, it is preferably one or more selected from sodium sulfite, sodium disulfate, potassium iodide, and sodium thiosulfate, and more preferably one or more selected from sodium sulfite, sodium disulfate, and potassium iodide. Note that the value in parentheses indicates the redox potential value.

[0014] <(b) Component> Component (b) is an alkali metal hydroxide. From the viewpoint of protein cleansing ability, component (b) is preferably at least one selected from sodium hydroxide, potassium hydroxide, and lithium hydroxide, more preferably at least one selected from sodium hydroxide and potassium hydroxide.

[0015] <Composition, etc.> From the viewpoint of formulation taking into consideration protein cleansing performance, maintenance of protein cleansing performance, and workability, the detergent composition for automatic dishwashers of the present invention may contain component (a) in an amount of preferably 0.0001% by mass or more, more preferably 0.0005% by mass or more, even more preferably 0.001% by mass or more, still more preferably 0.002% by mass or more, still more preferably 0.005% by mass or more, still more preferably 0.05% by mass or more, still more preferably 0.1% by mass or more, still more preferably 0.5% by mass or more, and still more preferably 1% by mass or more; and from the viewpoint of protein cleansing performance and maintenance of protein cleansing performance, it may contain component (a) in an amount of preferably 30% by mass or less, more preferably 20% by mass or less, even more preferably 15% by mass or less, still more preferably 12% by mass or less, and still more preferably 10% by mass or less. When used as a formulation that can be used as is without dilution (dilute formulation), the detergent composition for automatic dishwashers of the present invention can contain, for example, from the viewpoint of protein cleansing ability and maintaining protein cleansing ability, component (a) in an amount of preferably 0.0001% by mass or more, more preferably 0.0005% by mass or more, even more preferably 0.001% by mass or more, still more preferably 0.002% by mass or more, still more preferably 0.005% by mass or more, and preferably 5% by mass or less, more preferably 1% by mass or less, even more preferably 0.5% by mass or less, still more preferably 0.1% by mass or less, and still more preferably 0.05% by mass or less. Note that even formulations of these concentrations may be diluted before use. When preparing a formulation that can be diluted (concentrated formulation), the detergent composition for automatic dishwashers of the present invention may contain, for example, from the viewpoint of protein detergency and maintaining protein detergency, preferably 0.05% by mass or more of component (a), more preferably 0.1% by mass or more, even more preferably 0.5% by mass or more, still more preferably 1% by mass or more, and preferably 30% by mass or less, more preferably 20% by mass or less, even more preferably 15% by mass or less, still more preferably 12% by mass or less, and still more preferably 10% by mass or less. Note that even formulations of these concentrations may be used without dilution.

[0016] From the viewpoint of formulation taking into consideration protein cleaning performance and workability, the detergent composition for automatic dishwashers of the present invention may contain component (b) in an amount of preferably 0.0005% by mass or more, more preferably 0.0008% by mass or more, even more preferably 0.001% by mass or more, still more preferably 0.002% by mass or more, still more preferably 0.1% by mass or more, still more preferably 0.5% by mass or more, still more preferably 1% by mass or more, still more preferably 2% by mass or more, still more preferably 3% by mass or more, and preferably 20% by mass or less, more preferably 15% by mass or less, still more preferably 10% by mass or less, and still more preferably 5% by mass or less. When used as a formulation that can be used as is without dilution (dilute formulation), the detergent composition for automatic dishwashers of the present invention can contain, for example, from the viewpoint of protein cleaning ability, component (b) in an amount of preferably 0.0005% by mass or more, more preferably 0.0008% by mass or more, even more preferably 0.001% by mass or more, still more preferably 0.002% by mass or more, and preferably 0.05% by mass or less, more preferably 0.02% by mass or less, even more preferably 0.01% by mass or less, and still more preferably 0.005% by mass or less. Note that even formulations of these concentrations may be diluted before use. When used as a formulation that can be diluted (concentrated formulation), the detergent composition for automatic dishwashers of the present invention may contain, for example, from the viewpoint of protein cleaning performance, preferably 0.1% by mass or more of component (b), more preferably 0.5% by mass or more, even more preferably 1% by mass or more, still more preferably 2% by mass or more, still more preferably 3% by mass or more, and preferably 20% by mass or less, more preferably 15% by mass or less, still more preferably 10% by mass or less, and still more preferably 5% by mass or less. Note that even formulations of this concentration may be used without dilution.

[0017] In the detergent composition for automatic dishwashers of the present invention, the mass ratio (a) / (b) of the content of component (a) to the content of component (b) is, from the viewpoint of protein detergency, preferably 0.1 or more, more preferably 0.3 or more, even more preferably 0.5 or more, still more preferably 1 or more, still more preferably 1.5 or more, and is preferably 20 or less, more preferably 10 or less, even more preferably 5 or less, and still more preferably 3 or less.

[0018] From the viewpoint of detergency for protein stains, the detergent composition for automatic dishwashers of the present invention may further contain, as component (c), one or more selected from alkanolamines, silicates, and carbonates.

[0019] The alkanolamine may be one or more selected from monoethanolamine, diethanolamine, triethanolamine, N-methylmonoethanolamine, N-methyldiethanolamine, and N,N-dimethylmonoethanolamine. Examples of silicates include one or more selected from sodium silicate and potassium silicate, and more specifically, one or more selected from sodium metasilicate, sodium orthosilicate, No. 1 sodium silicate, No. 2 sodium silicate, No. 3 sodium silicate, No. 4 sodium silicate, 1K potassium silicate, and 2K potassium silicate. The carbonate may be one or more selected from sodium carbonate, potassium carbonate, lithium carbonate, and magnesium carbonate.

[0020] From the viewpoint of protein cleansing ability, component (c) is preferably one or more selected from monoethanolamine, sodium silicate, potassium silicate, sodium carbonate, and potassium carbonate, and more preferably one or more selected from monoethanolamine, sodium silicate, and potassium carbonate.

[0021] From the viewpoint of formulation taking into consideration protein cleaning performance and workability, the detergent composition for automatic dishwashers of the present invention may contain component (c) in an amount of preferably 0.0001% by mass or more, more preferably 0.0005% by mass or more, even more preferably 0.001% by mass or more, still more preferably 0.0015% by mass or more, still more preferably 0.1% by mass or more, still more preferably 0.5% by mass or more, still more preferably 1% by mass or more, still more preferably 1.5% by mass or more, and preferably 30% by mass or less, more preferably 20% by mass or less, still more preferably 15% by mass or less, and still more preferably 10% by mass or less. When used as a formulation that can be used as is without dilution (dilute formulation), the detergent composition for automatic dishwashers of the present invention can contain, for example, from the viewpoint of protein cleaning performance, preferably 0.0001% by mass or more of component (c), more preferably 0.0005% by mass or more, even more preferably 0.001% by mass or more, still more preferably 0.0015% by mass or more, and preferably 0.03% by mass or less, more preferably 0.02% by mass or less, even more preferably 0.015% by mass or less, and still more preferably 0.01% by mass or less. Note that even formulations of these concentrations may be diluted before use. When used as a formulation that can be diluted (concentrated formulation), the detergent composition for automatic dishwashers of the present invention may contain, for example, from the viewpoint of protein cleaning performance, preferably 0.1% by mass or more of component (c), more preferably 0.5% by mass or more, even more preferably 1% by mass or more, still more preferably 1.5% by mass or more, and preferably 30% by mass or less, more preferably 20% by mass or less, even more preferably 15% by mass or less, and still more preferably 10% by mass or less. Note that even formulations of this concentration may be used without dilution.

[0022] In the detergent composition for automatic dishwashers of the present invention, the mass ratio (a) / (c) of the content of component (a) to the content of component (c) is, from the viewpoint of protein detergency, preferably 0.1 or more, more preferably 0.5 or more, even more preferably 1 or more, still more preferably 1.5 or more, still more preferably 3 or more, still more preferably 4 or more, and is preferably 50 or less, more preferably 30 or less, still more preferably 20 or less, still more preferably 10 or less, and still more preferably 7 or less.

[0023] From the viewpoint of protein cleaning performance, the detergent composition for automatic dishwashers of the present invention may further contain a chelating agent as component (d).

[0024] From the viewpoint of protein cleansing ability, component (d) is preferably a chelating agent having a calcium stability constant pKCa of 2 or more at pH 11 and 25°C. From the viewpoint of cleansing power for protein stains, the calcium stability constant pKCa of component (d) is preferably 2 or more, more preferably 2.5 or more, even more preferably 3 or more, and from the viewpoint of easy availability, it is preferably 15 or less, more preferably 10 or less, even more preferably 6 or less. The calcium stability constant pKCa is determined by the following method. Using a calcium ion-selective electrode (e.g., manufactured by HORIBA), 0.2 mL of a 2 g / L calcium chloride solution at 25°C was dropped into 100 mL of distilled water at 25°C, and the potential was measured. A linear approximation equation was calculated by plotting the logarithm of the calcium ion concentration at each drop on the horizontal axis and the potential on the vertical axis. Subsequently, distilled water was added to component (d) to adjust the concentration to 1 g / L, and the pH was adjusted to 11 with 1 N sodium hydroxide and / or 1 N hydrochloric acid to prepare a chelating agent solution. 100 mL of the chelating agent solution was removed, cooled to 25°C, and 3 mL of a 2 g / L calcium chloride solution at 25°C was dropped into the solution. The potential was measured using a calcium ion-selective electrode (e.g., manufactured by HORIBA). The potential at this time was substituted into the approximate equation to calculate the untrapped calcium concentration A (mol / L) in the chelating agent solution, and then substituted into the following equation along with the chelating agent concentration B (mol / L) to calculate KCa, and the logarithm was taken to calculate pKCa. KCa = (5.4 × 10 -5 -A) / (A×(B-(5.4×10 -5 -A)

[0025] Specifically, component (d) is one or more selected from ethylenediaminetetraacetic acid (pKCa12.2), tripolyphosphate (pKCa5.9), polyacrylic acid (pKCa3.2), acrylic acid-maleic acid copolymer (pKCa approximately 3.5 (may vary depending on the monomer ratio)), citric acid (pKCa3.2), glutamic acid diacetate (pKCa6.5), methylglycine diacetate (pKCa6.3), L-aspartic acid N,N-diacetate (pKCa7.0), and salts thereof. From the viewpoint of protein cleaning ability, it is preferably one or more selected from ethylenediaminetetraacetic acid, polyacrylic acid, acrylic acid-maleic acid copolymer, citric acid, methylglycine diacetate, and salts thereof, and more preferably one or more selected from polyacrylic acid, citric acid, methylglycine diacetate, and salts thereof. Examples of the salt include alkali metal salts such as sodium and potassium, ammonium salts, and alkanolamine salts such as monoethanolamine and triethanolamine, with potassium salts and sodium salts being preferred from the viewpoint of availability.

[0026] The polyacrylic acid or salt thereof of component (d) may be a copolymer containing a monomer other than acrylic acid that is copolymerizable with acrylic acid (excluding maleic acid). The molar ratio of the monomer copolymerizable with acrylic acid (excluding maleic acid) to all constituent monomers is 0 mol% or more and 5 mol% or less, preferably 3 mol% or less, and more preferably 0 mol% from the viewpoint of protein cleansing ability. Furthermore, the weight-average molecular weight of the polyacrylic acid or salt thereof of component (c) is 1,000 or more, preferably 2,000 or more and 20,000 or less, preferably 17,000 or less, from the viewpoint of protein cleansing ability and workability. This weight-average molecular weight was determined by gel permeation chromatography using a mixed solvent of acetonitrile and water (phosphate buffer solution) as the developing solvent and a commercially available polymer standard reagent (e.g., a molecular weight standard reagent manufactured by Sigma-Aldrich) with a known molecular weight as the standard substance.

[0027] From the viewpoint of protein cleansing ability, the acrylic acid-maleic acid copolymer or salt thereof of component (d) has an acrylic acid / maleic acid molar ratio of 0.25 or more, preferably 0.4 or more, and 4 or less, preferably 2.5 or less. The acrylic acid-maleic acid copolymer or salt thereof of component (d) may be a copolymer containing a monomer other than acrylic acid and maleic acid that is copolymerizable with acrylic acid and / or maleic acid. From the viewpoint of protein cleansing ability, the molar ratio of the monomer other than acrylic acid and maleic acid that is copolymerizable with acrylic acid and / or maleic acid to the total constituent monomers is 0 mol% or more and 5 mol% or less, preferably 3 mol% or less, more preferably 0 mol%. Furthermore, from the viewpoints of protein cleansing ability and workability, the weight-average molecular weight of the acrylic acid-maleic acid copolymer or salt thereof of component (d) is 1,000 or more, preferably 2,000 or more, and preferably 100,000 or less, more preferably 90,000 or less. This weight-average molecular weight was determined by gel permeation chromatography using a mixed solvent of acetonitrile and water (phosphate buffer solution) as a developing solvent and polyacrylic acid, a commercially available polymer standard reagent with a known molecular weight (e.g., molecular weight standard reagent manufactured by Sigma-Aldrich), as a standard substance.

[0028] From the viewpoint of formulation taking into consideration protein cleaning performance and workability, the detergent composition for automatic dishwashers of the present invention may contain component (d) in an amount of preferably 0.0001% by mass or more, more preferably 0.0005% by mass or more, even more preferably 0.001% by mass or more, still more preferably 0.002% by mass or more, still more preferably 0.1% by mass or more, still more preferably 0.5% by mass or more, still more preferably 1% by mass or more, still more preferably 2% by mass or more, and preferably 50% by mass or less, more preferably 25% by mass or less, still more preferably 15% by mass or less, and still more preferably 10% by mass or less. When used as a formulation that can be used as is without dilution (dilute formulation), the detergent composition for automatic dishwashers of the present invention can contain, for example, from the viewpoint of protein cleaning performance, preferably 0.0001% by mass or more of component (d), more preferably 0.0005% by mass or more, even more preferably 0.001% by mass or more, still more preferably 0.002% by mass or more, and preferably 0.05% by mass or less, more preferably 0.025% by mass or less, even more preferably 0.015% by mass or less, and still more preferably 0.01% by mass or less. Note that even formulations of these concentrations may be diluted before use. When used as a formulation that can be diluted (concentrated formulation), the detergent composition for automatic dishwashers of the present invention may contain, for example, from the viewpoint of protein cleaning performance, preferably 0.1% by mass or more of component (d), more preferably 0.5% by mass or more, even more preferably 1% by mass or more, still more preferably 2% by mass or more, and preferably 50% by mass or less, more preferably 25% by mass or less, even more preferably 15% by mass or less, and still more preferably 10% by mass or less. Note that even formulations of this concentration may be used without dilution. In the present invention, the mass of component (d) is defined as a value converted into the sodium salt.

[0029] In the detergent composition for automatic dishwashers of the present invention, the mass ratio (a) / (d) of the content of component (a) to the content of component (d) is, from the viewpoint of protein detergency, preferably 0.01 or more, more preferably 0.1 or more, even more preferably 0.5 or more, still more preferably 1 or more, and preferably 50 or less, more preferably 30 or less, even more preferably 20 or less, still more preferably 10 or less, still more preferably 5 or less, and still more preferably 3 or less.

[0030] The detergent composition for automatic dishwashers of the present invention may further contain a surfactant as component (e) from the viewpoints of protein detergency, oil detergency and foam suppression.

[0031] As the surfactant of component (e), a nonionic surfactant is preferred from the viewpoints of protein cleansing ability, oil cleansing ability, and foam suppression ability. Examples of nonionic surfactants for component (e) include polyoxyalkylene alkyl ethers, polyoxyalkylene alkenyl ethers, polyoxyalkylene sorbitan fatty acid esters, alkyl glycosides, alkyl polyglycosides, sucrose fatty acid esters, and alkyl polyglyceryl ethers, and these may be used alone or in combination. From the viewpoint of protein cleansing ability, the number of carbon atoms in the alkyl or alkenyl group of these nonionic surfactants is preferably 6 or more, more preferably 8 or more, and preferably 22 or less, more preferably 18 or less. From the viewpoint of protein cleansing ability, the alkylene oxide in the polyoxyalkylene alkyl ether, polyoxyalkylene alkenyl ether, or polyoxyalkylene sorbitan fatty acid ester preferably contains an alkylene oxide selected from ethylene oxide and propylene oxide, and from the viewpoint of protein cleansing ability, the average number of moles of alkylene oxide added is preferably 2 or more and preferably 25 or less.

[0032] The component (e) is preferably a polyoxyalkylene alkyl ether (hereinafter referred to as component (e1)). From the viewpoint of protein cleansing ability, the number of carbon atoms in the alkyl group in component (e1) is preferably 10 or more, more preferably 12 or more, and preferably 20 or less, more preferably 18 or less, and even more preferably 16 or less. From the viewpoint of protein cleansing ability, the alkylene oxide in component (e1) preferably includes an alkylene oxide selected from ethylene oxide and propylene oxide. Furthermore, from the viewpoint of protein cleansing ability, the average number of moles of alkylene oxide added in component (e1) is preferably 2 or more, more preferably 4 or more, and preferably 20 or less, more preferably 18 or less.

[0033] Examples of component (e1) include secondary alcohol alkylene oxide adducts having 10 to 24 carbon atoms. From the viewpoint of protein cleansing ability, the number of carbon atoms in the secondary alcohol is preferably 10 or more, more preferably 12 or more, and preferably 20 or less, more preferably 18 or less, and even more preferably 16 or less. Examples include primary alcohol alkylene oxide adducts having 10 to 24 carbon atoms. From the viewpoint of protein cleansing ability, the number of carbon atoms in the primary alcohol is preferably 10 or more, more preferably 12 or more, and preferably 20 or less, more preferably 18 or less, and even more preferably 16 or less. From the viewpoint of protein cleansing ability, the alkylene oxide is preferably an alkylene oxide having 2 to 4 carbon atoms. From the viewpoint of protein cleansing ability, the alkylene oxide preferably contains an alkylene oxide selected from ethylene oxide and propylene oxide. From the viewpoint of protein cleansing ability, the average number of moles of alkylene oxide added is preferably 2 or more, more preferably 4 or more, and preferably 20 or less, more preferably 18 or less.

[0034] From the viewpoints of foam-suppressing property and formulation taking into consideration protein cleansing ability, oil cleansing ability, and workability, the detergent composition for automatic dishwashers of the present invention may contain component (e) in an amount of preferably 0.00001% by mass or more, more preferably 0.0001% by mass or more, even more preferably 0.0005% by mass or more, still more preferably 0.001% by mass or more, still more preferably 0.01% by mass or more, still more preferably 0.1% by mass or more, still more preferably 0.5% by mass or more, still more preferably 1.0% by mass or more, and preferably 20% by mass or less, more preferably 15% by mass or less, even more preferably 10% by mass or less, and still more preferably 5% by mass or less. When used as a formulation that can be used as is without dilution (dilute formulation), the detergent composition for automatic dishwashers of the present invention can contain, for example, from the viewpoints of protein detergency, oil detergency, and foam suppression, component (e) in an amount of preferably 0.00001% by mass or more, more preferably 0.0001% by mass or more, even more preferably 0.0005% by mass or more, still more preferably 0.001% by mass or more, and preferably 0.02% by mass or less, more preferably 0.015% by mass or less, even more preferably 0.01% by mass or less, and still more preferably 0.005% by mass or less. Note that even formulations of these concentrations may be diluted before use. When preparing a formulation that can be diluted (concentrated formulation), the detergent composition for automatic dishwashers of the present invention may contain component (e) in an amount of preferably 0.01% by mass or more, more preferably 0.1% by mass or more, even more preferably 0.5% by mass or more, still more preferably 1.0% by mass or more, and preferably 20% by mass or less, more preferably 15% by mass or less, even more preferably 10% by mass or less, and still more preferably 5% by mass or less, from the viewpoints of, for example, protein detergency, oil detergency, and foam suppression. Note that even formulations of these concentrations may be used without dilution.

[0035] In the detergent composition for automatic dishwashers of the present invention, the ranges of the contents of components (a), (b), (c), (d), and (e) can be set by arbitrarily selecting and combining the aforementioned values.

[0036] From the viewpoint of protein cleaning ability, the detergent composition for automatic dishwashers of the present invention has a pH at 25°C of more than 11, preferably 11.5 or more, more preferably 12 or more, and 14 or less. This pH is measured by the following method. (1) pH measurement method A pH measurement composite electrode (Horiba, Ltd., glass-ground sleeve type) with a saturated potassium chloride aqueous solution (3.33 mol / L) as the pH electrode internal solution was connected to a pH meter (Horiba, Ltd., pH / ion meter F-23). ​​Next, a pH 4.01 standard solution (phthalate standard solution), a pH 6.86 standard solution (neutral phosphate standard solution), and a pH 9.18 standard solution (borate standard solution) were each filled into 100 mL beakers and immersed in a thermostatic bath at 25°C for 30 minutes. The pH measurement electrode was immersed in the thermostatically adjusted standard solution for 3 minutes, and calibration was performed in the order of pH 6.86 → pH 9.18 → pH 4.01. The automatic dishwasher detergent composition to be measured was adjusted to 25°C, and the electrode of the pH meter was immersed in the sample. The pH was measured after 1 minute.

[0037] From the viewpoints of protein cleaning ability and safety to humans, the detergent composition for automatic dishwashers of the present invention preferably has a pH at 25°C of 9 or more, more preferably 10 or more, and preferably 12 or less, more preferably 11 or less, when diluted with water to a concentration of 0.1% by mass. This pH is measured by the above-mentioned measurement method (wherein "detergent composition for automatic dishwashers" is read as "diluted detergent composition for automatic dishwashers").

[0038] The detergent composition for automatic dishwashers of the present invention preferably contains water from the viewpoint of the stability and workability of the composition. The water is not particularly limited, but examples thereof include tap water, well water, ion-exchanged water, and distilled water. The water is preferably used in an amount that makes up the remainder of the composition (amount that makes the total 100% by mass). The water content can be, for example, 40% by mass or more, further 45% by mass or more, further 50% by mass or more, further 55% by mass or more, further 60% by mass or more, further 65% by mass or more, or even 70% by mass or more of the composition.

[0039] The detergent composition for automatic dishwashers of the present invention may contain ingredients such as enzymes (protease, lipase, carbohydrate-degrading enzyme, etc.), solvents, hydrotropes, dispersants, pH adjusters, thickeners, viscosity modifiers, fragrances, colorants, antioxidants, preservatives, foam suppressors, bleaches, bleach activators, etc. (excluding those corresponding to components (a) to (e)) within the scope of the present invention.

[0040] From the viewpoint of protein cleaning performance, the viscosity of the detergent composition for automatic dishwashers of the present invention at 20°C may be, for example, 1200 mPa·s or less, or even 1000 mPa·s or less. The lower limit of the viscosity may be 0 mPa·s or more. This viscosity is measured using a Brookfield viscometer.

[0041] In the present invention, tableware refers to: (i) In addition to so-called tableware such as plates, bowls, cups, chopsticks, knives, forks, and spoons, (ii) Storage containers such as Tupperware and bottles, (iii) Cooking utensils such as knives, cutting boards, pots, frying pans, and fish grills; (iv) Storage or transport equipment such as racks, containers, etc. It may also mean components or utensils that come into contact with food ingredients, such as:

[0042] <How to wash dishes> The present invention provides a method for washing tableware, which comprises using an automatic dishwasher to wash tableware having protein-containing stains with a cleaning liquid prepared by diluting the detergent composition for automatic dishwashers of the present invention with water. The items described for the detergent composition for automatic dishwashers of the present invention can be appropriately applied to the dishwashing method of the present invention. The components (a), (b), (c), (d), and (e), their mass ratios, pH, and specific and preferred examples of tableware are also the same as those for the detergent composition for automatic dishwashers of the present invention.

[0043] The cleaning liquid of the present invention may be prepared by diluting the detergent composition for automatic dishwashers of the present invention with water more than 1-fold, further 300-fold or more, and 2000-fold or less, further 1500-fold or less.

[0044] From the viewpoint of protein cleansing ability and maintaining protein cleansing ability, the cleaning solution of the present invention can contain component (a), for example, preferably 0.0001% by mass or more, more preferably 0.0005% by mass or more, even more preferably 0.001% by mass or more, still more preferably 0.002% by mass or more, even more preferably 0.005% by mass or more, and preferably 5% by mass or less, more preferably 1% by mass or less, even more preferably 0.5% by mass or less, still more preferably 0.1% by mass or less, and even more preferably 0.05% by mass or less.

[0045] From the viewpoint of protein cleaning ability, the cleaning solution of the present invention can contain component (b), for example, preferably 0.0005% by mass or more, more preferably 0.0008% by mass or more, even more preferably 0.001% by mass or more, still more preferably 0.002% by mass or more, and preferably 0.05% by mass or less, more preferably 0.02% by mass or less, even more preferably 0.01% by mass or less, and still more preferably 0.005% by mass or less.

[0046] From the viewpoint of protein cleaning ability, the cleaning solution of the present invention can contain component (c) in an amount of, for example, preferably 0.0001% by mass or more, more preferably 0.0005% by mass or more, even more preferably 0.001% by mass or more, still more preferably 0.0015% by mass or more, and preferably 0.03% by mass or less, more preferably 0.02% by mass or less, even more preferably 0.015% by mass or less, and still more preferably 0.01% by mass or less.

[0047] From the viewpoint of protein cleaning ability, the cleaning solution of the present invention can contain component (d), for example, preferably 0.0001% by mass or more, more preferably 0.0005% by mass or more, even more preferably 0.001% by mass or more, still more preferably 0.002% by mass or more, and preferably 0.05% by mass or less, more preferably 0.025% by mass or less, even more preferably 0.015% by mass or less, and still more preferably 0.01% by mass or less.

[0048] From the viewpoint of protein cleansing ability, oil cleansing ability and foam suppression ability, the cleaning solution of the present invention can contain component (e) in an amount of, for example, preferably 0.00001% by mass or more, more preferably 0.0001% by mass or more, even more preferably 0.0005% by mass or more, still more preferably 0.001% by mass or more, and preferably 0.02% by mass or less, more preferably 0.015% by mass or less, even more preferably 0.01% by mass or less, and still more preferably 0.005% by mass or less.

[0049] In the present invention, the ranges of the contents of the components (a), (b), (c), (d), and (e) in the cleaning solution can be set by arbitrarily selecting and combining the aforementioned values.

[0050] From the viewpoint of protein cleaning ability and safety for humans, the pH of the cleaning solution of the present invention is preferably 9 or higher, more preferably 9.5 or higher, even more preferably 10 or higher, and preferably 12 or lower, more preferably 11.5 or lower, even more preferably 11 or lower.

[0051] In the dish washing method of the present invention, the washing liquid is brought into contact with the dish for, for example, 20 seconds or more, further 30 seconds or more, further 40 seconds or more, and then 600 seconds or less, further 300 seconds or less, further 180 seconds or less, from the viewpoint of protein cleaning ability.

[0052] In the tableware washing method of the present invention, the temperature of the washing liquid can be, for example, 30°C or higher, further 35°C or higher, further 40°C or higher, and 90°C or lower, further 80°C or lower, further 70°C or lower.

[0053] In the dishwashing method of the present invention, the flow rate of the cleaning liquid when contacting the dishwashing liquid is preferably 5 m / min or more, more preferably 10 m / min or more, even more preferably 50 m / min or more, from the viewpoint of protein cleaning ability, and preferably 2000 m / min or less, more preferably 1000 m / min or less, more preferably 500 m / min or less.

[0054] The protein-containing stain may be a protein-containing stain derived from egg yolk.

[0055] After the dishware is contacted with the cleaning solution, the dishware is rinsed with water at a temperature of 50°C or higher, preferably 55°C or higher, more preferably 60°C or higher, and 80°C or lower. The rinsing time for the dishes is 4 seconds or more, preferably 5 seconds or more, and 10 seconds or less, preferably 9 seconds or less. The flow rate of the rinse water is preferably 5 m / min or more, more preferably 10 m / min or more, even more preferably 100 m / min or more, and preferably 2500 m / min or less, more preferably 2000 m / min or less, even more preferably 1500 m / min or less.

[0056] The automatic dishwasher may be any dishwasher generally available on the market, and although a household automatic dishwasher may be used, a commercial automatic dishwasher is preferred. When washing with a commercial dishwasher, the detergent composition of the present invention is generally used as a cleaning liquid mixed with water. In this case, the composition is arbitrarily transferred in a fixed amount into the commercial dishwasher by a supply device, and an appropriate concentration of the cleaning liquid is maintained. For example, the detergent composition of the present invention is supplied by inserting a tube dedicated to commercial dishwashers directly into a container such as a plastic container filled with the composition and sucking it up. The cleaning liquid is then supplied into the commercial dishwasher.

[0057] In the method for washing tableware of the present invention, the washing liquid after washing the tableware may be collected in the tank and the collected washing liquid may be reused for washing tableware. When the cleaning liquid used to wash dishes is collected in a tank and reused as a cleaning liquid for dishes, the liquid may become mixed with dirt adhering to the dishes or may be diluted with rinse water, causing the liquid's pH to fall within the neutral to weak alkaline range, making it difficult to remove stains containing protein. However, the cleaning liquid of the present invention can remove stains containing protein even when the liquid's pH falls within the neutral to weak alkaline range. [Example]

[0058] The ingredients used in the examples and comparative examples are listed below.

[0059] <Component (a)> Sodium sulfite: oxidation-reduction potential 50 mV, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. Potassium iodide: Oxidation-reduction potential 28 mV, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. Sodium thiosulfate: Oxidation-reduction potential 5mV, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.

[0060] <Component (a') (comparison component of component (a))> Sodium dithionite: oxidation-reduction potential 76 mV, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.

[0061] The oxidation-reduction potentials of the components (a) and (a') were measured by the following method. A solution was prepared by adding distilled water to component (a) or (a') to a concentration of 0.016 mol / L, and adjusting the pH to 7.5 with 1 mol / L hydrochloric acid and / or sodium hydroxide. The temperature of the solution was adjusted to 60°C, and the oxidation-reduction potential was measured using an ORP meter (ORP5 Pen ORP Meter) manufactured by Cem Corporation.

[0062] <(b) Component> KOH: Potassium hydroxide, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. NaOH: Sodium hydroxide, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.

[0063] <(c) component> Monoethanolamine: Monoethanolamine, manufactured by Mitsui Chemicals, Inc. Potassium silicate: Choline S-458-K (potassium silicate aqueous solution) manufactured by Koei Chemical Co., Ltd. Sodium carbonate: Sodium carbonate, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.

[0064] <(d) component> Citric acid (Na salt): Sodium citrate, pKCa3.4, manufactured by Showa Kako Co., Ltd. MGDA (Na salt): Sodium methylglycine diacetate, TRILON M LIQUID-JP, pKCa6.3, manufactured by BASF SE Polyacrylic acid (Na salt): Sodium polyacrylate, Poise 530, pKCa 3.2, molecular weight 17,000, manufactured by Kao Corporation

[0065] The calcium stability constant pKCa of component (d) at pH 11 and 25°C was measured by the following method. Using a HORIBA calcium ion-selective electrode, 0.2 mL of a 2 g / L calcium chloride solution at 25°C was dropped into 100 mL of distilled water at 25°C, and the potential was measured. A linear approximation equation was calculated by plotting the logarithm of the calcium ion concentration at each drop on the horizontal axis and the potential on the vertical axis. Subsequently, distilled water was added to component (d) to adjust the concentration to 1 g / L, and the pH was adjusted to 11 with 1 N sodium hydroxide and / or 1 N hydrochloric acid to prepare a chelating agent solution. 100 mL of the chelating agent solution was taken, cooled to 25°C, and 3 mL of a 2 g / L calcium chloride solution at 25°C was dropped into it. The potential was measured using a HORIBA calcium ion-selective electrode. The potential was substituted into the approximation equation to calculate the untrapped calcium concentration A (mol / L) in the chelating agent solution. This was then substituted into the following equation along with the chelating agent concentration B (mol / L) to calculate KCa, and the logarithm was taken to calculate pKCa. KCa = (5.4 × 10 -5 -A) / (A×(B-(5.4×10 -5 -A)

[0066] <(e) component> EP7085: secC12-14EO(7)PO(8.5), "SOFTANOL EP7085", manufactured by Nippon Shokubai Co., Ltd., a nonionic surfactant in which an average of 7 moles of ethylene oxide and an average of 8.5 moles of propylene oxide are added to a secondary alcohol having 12 to 14 carbon atoms, in that order. LS106: C12-14EO(3)PO(1.5)EO(4), Emulgen LS 106, manufactured by Kao Corporation, a nonionic surfactant in which an average of 3 moles of ethylene oxide, an average of 1.5 moles of propylene oxide, and an average of 3 moles of ethylene oxide are added to a primary alcohol having 12 to 14 carbon atoms, in this order.

[0067] <Other ingredients> C8COONa: Sodium caprylate, Lunac 8-98(E), manufactured by Kao Corporation

[0068] The cleaning power for thermally denatured egg yolk stains was evaluated using the detergent compositions for automatic dishwashers shown in Tables 1 and 2 according to the following procedure. The results are shown in Tables 1 and 2. The pH of the compositions in Tables 1 and 2 was adjusted with sodium hydroxide and / or sulfuric acid as necessary.

[0069] (1) The mass (mass A) of a ceramic round plate (diameter 235 mm, diameter of the recess 140 mm) was measured. (2) 3 g of egg yolk was applied to the recess of the round plate and dried at 80°C for 30 minutes to prepare heat-denatured egg yolk stains. (3) The mass of the round plate after drying (mass B) was measured. (4) The detergent compositions for automatic dishwashers shown in Tables 1 and 2 were diluted with water to a concentration of 0.1% by mass to prepare cleaning solutions, and the pH at 25°C was measured. (5) Using a JWE-680A dishwasher manufactured by Hoshizaki Electric Co., Ltd., the round plate was washed with the prepared cleaning solution at a temperature of 60°C for 40 seconds at a flow rate of 200m / min, and then rinsed a few seconds later with fresh water at 80°C for 6 seconds at a flow rate of 1000m / min. (6) The mass of the round plate after washing (mass C) was measured, and the mass change rate was evaluated as the rate of cleaning of heat-denatured egg yolk stains. Specifically, the mass change rate can be calculated using the following formula. Mass change rate (%) = [[BC] / [BA]] x 100 (7) A cleaning liquid was prepared by diluting the detergent composition for automatic dishwashers shown in Tables 1 and 2 with water to a concentration of 0.1% by mass. Model soil (1N acetic acid) was added to the cleaning liquid in the amount shown in Tables 1 and 2 and stirred to prepare a cleaning liquid containing the soil, and the pH at 25°C was measured. (8) The above (5) and (6) were carried out using the prepared cleaning solution containing the soil, and the mass change rate was calculated and evaluated as the cleaning rate of heat-denatured egg yolk soil.

[0070] [Table 1]

[0071] [Table 2]

Claims

1. A detergent composition for automatic dishwashers, comprising the following component (a) in an amount of 5% by mass or more and 15% by mass or less, component (b) and water, and having a pH at 25°C of more than 11 and 14 or less, the detergent composition being used by diluting with water: Component (a): a reducing agent having an oxidation-reduction potential of +71 mV or less Component (b): hydroxide of alkali metal

2. 2. The detergent composition for automatic dishwashers according to claim 1, wherein component (a) is at least one selected from the group consisting of sulfites, disulfates, thiosulfates, and iodides.

3. 3. The detergent composition for an automatic dishwasher according to claim 1, wherein the component (a) is at least one selected from the group consisting of sodium sulfite, potassium sulfite, sodium disulfate, potassium disulfate, sodium thiosulfate, potassium thiosulfate, sodium iodide, and potassium iodide.

4. 4. The detergent composition for automatic dishwashers according to claim 1, wherein component (b) is at least one selected from the group consisting of sodium hydroxide, potassium hydroxide, and lithium hydroxide.

5. 5. The detergent composition for an automatic dishwasher according to claim 1, wherein the mass ratio (a) / (b) of the content of the component (a) to the content of the component (b) is 0.1 or more and 20 or less.

6. The detergent composition for automatic dishwashers according to any one of claims 1 to 5, further comprising the following component (c): Component (c): one or more selected from alkanolamines, silicates, and carbonates

7. 7. The automatic dishwashing detergent of claim 6, wherein component (c) is one or more selected from the group consisting of monoethanolamine, sodium silicate, potassium silicate, sodium carbonate, and potassium carbonate. Machine cleaning compositions.

8. The detergent composition for automatic dishwashers according to any one of claims 1 to 7, further comprising the following component (d): Component (d): Chelating agent

9. 9. The detergent composition for use in automatic dishwashers according to claim 8, wherein component (d) is a chelating agent having a calcium stability constant pKCa of 2 or more at pH 11 and 25°C.

10. 10. The detergent composition for an automatic dishwasher according to claim 8 or 9, wherein component (d) is at least one selected from ethylenediaminetetraacetic acid, polyacrylic acid, acrylic acid-maleic acid copolymer, citric acid, methylglycine diacetic acid, and salts thereof.

11. The detergent composition for automatic dishwashers according to any one of claims 1 to 10, further comprising the following component (e): Component (e): surfactant

12. The detergent composition for use in automatic dishwashers according to claim 11, wherein component (e) is at least one selected from nonionic surfactants.

13. A method for washing tableware, comprising using an automatic dishwasher to wash tableware having protein-containing stains thereon with a cleaning liquid prepared by diluting the detergent composition for an automatic dishwasher according to any one of claims 1 to 12 with water.

14. The dishwasher detergent composition according to any one of claims 1 to 12, wherein the cleaning liquid is prepared by diluting the dishwasher detergent composition according to any one of claims 1 to 12 with water at a ratio of more than 1 to 2000 times.

15. The method for washing tableware according to claim 13 or 14, wherein the washing liquid is brought into contact with the tableware for 20 seconds or more and 600 seconds or less.

16. The method for washing tableware according to any one of claims 13 to 15, wherein the temperature of the washing liquid is 40°C or higher and 80°C or lower.

17. The method for washing tableware according to any one of claims 13 to 16, wherein the protein-containing stain is a stain containing protein derived from egg yolk.

18. The method for washing tableware according to any one of claims 13 to 17, wherein the washing liquid after washing the tableware is collected in a tank and reused as the washing liquid.

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