Detergent composition for hard surfaces

Abstract

The present invention relates to a detergent composition for hard surfaces, the detergent composition containing a fluoride, and provides: a detergent composition for hard surfaces, the composition achieving both corrosion prevention of a hard surface and water stain removal performance under mild conditions in a weak acidic to neutral region; and a method for cleaning a hard surface using the detergent composition for hard surfaces.　Disclosed is a detergent composition for hard surfaces, the detergent composition containing (a) a fluoride (hereinafter referred to as a component (a)) and (b) an organic acid or a salt thereof. The content of the component (a) is 4 mM to 240 mM inclusive in terms of fluorine atoms, and the pH at 25°C is 4.0 to 6.5 inclusive. The hydrogen fluoride concentration [HF] in the detergent composition for hard surfaces calculated from (formula 1) is 0.25 mM to 0.9 mM inclusive.　(Formula 1) 7.08 × 10-4 = [F-][H+] / [HF] [F-]: the ionized fluorine content (mM) in the component (a) contained in the detergent composition for hard surfaces [H+]: the hydrogen ion concentration (mM) calculated from the pH of the detergent composition for hard surfaces at 25°C 7.08 × 10-4: the acid ionization constant of hydrogen fluoride at 25°C

Description

Cleaning composition for hard surfaces

[0001] The present invention relates to a cleaning composition for hard surfaces and a method for cleaning hard surfaces.

[0002] BACKGROUND ART The living environment surrounding us includes various hard surfaces made of materials such as tiles, plastics, and metals. These hard surfaces are exposed to environments in which various types of dirt adhere in daily life. In particular, hard surfaces used in bathrooms, kitchens, and other facilities are surfaces that people come into contact with on a daily basis, making them prone to the accumulation of residual dirt and difficult to clean. Bathroom cleaners typically used in bathrooms, such as bathtubs and bathroom walls and floors, contain surfactants, solvents, sequestering agents, and the like to remove metal soap stains, particularly calcium salts of fatty acids. Furthermore, in bathrooms and kitchens, silicic acid contained in water polymerizes and accumulates on hard surfaces, depositing in a scale-like pattern and forming limescale stains. This limescale stain is also known to be extremely difficult to remove.

[0003] Chinese Patent Publication No. 106190617 discloses a glass scale cleaner containing 0.5-10 parts surfactant, 0.5-15 parts fluoride, 10-30 parts weak acid, 1-3 parts acrylic acid homopolymer sodium salt, 1-10 parts borax, 5-20 parts solvent, and 40-70 parts demineralized water.Chinese Patent Publication No. 111979054 discloses a neutral, environmentally friendly bathroom cleaner containing 0.3-5% cleaning promoter, 10-25% organic acid, 5-15% neutralizer, 0.1-0.5% corrosion inhibitor, 1-5% chelating dispersant, 1-5% surfactant, and the remainder deionized water.

[0004] SUMMARY OF THE INVENTION

[0003] Conventionally, strongly acidic detergent compositions have been used to remove limescale stains from hard surfaces used in bathrooms, kitchens, etc., and hypochlorous acid-based detergent compositions have been used to remove black mold stains from such hard surfaces. For example, when a strongly acidic detergent composition and a hypochlorous acid-based detergent composition are simultaneously used to clean hard surfaces such as bathrooms, there is a risk of accidentally mixing the two detergent compositions, resulting in the generation of harmful chlorine, which is extremely dangerous. Therefore, there is a need for a detergent composition that is excellent at removing limescale stains from hard surfaces under mild conditions with a near-neutral pH. Patent Document 1 also discloses a detergent composition for hard surfaces that contains fluoride under strongly acidic conditions. However, while such detergent compositions can remove limescale stains, they corrode hard surfaces such as glass and aluminum, and therefore require the incorporation of a corrosion inhibitor such as borax. Therefore, there is a demand for a fluoride-containing cleaning composition for hard surfaces that has both water stain removal performance and corrosion prevention properties under mild conditions in the weakly acidic to neutral range.

[0005] The present invention relates to a fluoride-containing detergent composition for hard surfaces, and provides a detergent composition for hard surfaces that achieves both water stain removal performance and corrosion prevention for hard surfaces under mild conditions in the weakly acidic to neutral range, and a method for cleaning hard surfaces using the same.

[0006] The present invention relates to a hard surface cleaning composition containing (a) a fluoride (hereinafter referred to as component (a)) and (b) an organic acid or a salt thereof (hereinafter referred to as component (b)), wherein the content of component (a) is 4 mM or more and 240 mM or less in terms of fluorine atoms, the pH at 25°C is 4.0 or more and 6.5 or less, and the hydrogen fluoride concentration [HF] in the hard surface cleaning composition, calculated by the following (Equation 1), is 0.25 mM or more and 0.9 mM or less. －４ = [F － ][H ＋ ] / [HF] (Formula 1) [F － ]: the content (mM) of ionized fluorine in component (a) contained in the hard surface cleaning composition [H ＋]: hydrogen ion concentration (mM) calculated from the pH of the hard surface cleaning composition at 25 ° C. 7.08 × 10 －４ : Acid ionization constant of hydrogen fluoride at 25°C

[0007] The present invention also relates to a method for cleaning a hard surface, which comprises contacting the hard surface with a hard surface cleaner composition for a predetermined period of time, and then rinsing the hard surface with water.

[0008] According to the present invention, there are provided a fluoride-containing hard surface cleaning composition that achieves both water stain removal performance and corrosion prevention for hard surfaces under mild conditions in the weakly acidic to neutral range, and a method for cleaning hard surfaces using the same. Furthermore, in one aspect of the hard surface cleaning composition of the present invention, the water stain removal performance and corrosion prevention for hard surfaces can be achieved simultaneously without containing a corrosion inhibitor for hard surfaces.

[0009] Modes for Carrying Out the Invention The reason why the hard surface cleaning composition of the present invention is able to achieve both limescale removal performance and corrosion prevention for hard surfaces under mild conditions in the weakly acidic to neutral range is not entirely clear, but is presumed to be as follows. Limescale is formed by the repeated deposition of calcium carbonate and silicic acid dissolved in water on hard surfaces. It is believed that the fluoride, which is component (a) contained in the hard surface cleaning composition of the present invention, partially converts to hydrogen fluoride (HF) depending on the pH of the cleaning composition, and that this hydrogen fluoride acts on silicic acid deposits to exhibit removal performance; the lower the pH, the higher the hydrogen fluoride concentration, and the better the limescale removal performance. On the other hand, glass hard surfaces also have silicic acid as a structural unit, and there is a trade-off between limescale removal performance and corrosion prevention for hard surfaces such as glass. The present inventors discovered that by strictly controlling the amount of fluoride contained in the hard surface cleaning composition of the present invention, the pH, and the hydrogen fluoride concentration in the cleaning composition, and by adding an organic acid or a salt thereof as component (b), it is possible to achieve both water stain removal performance and corrosion prevention for hard surfaces even under mild conditions in the weakly acidic to neutral range, and thus arrived at the present invention.

[0010] [Cleaning composition for hard surfaces] <Component (a)> The cleaning composition for hard surfaces of the present invention contains a fluoride as component (a). Examples of the fluoride as component (a) include one or more selected from hydrogen fluoride, sodium fluoride, potassium fluoride, zinc fluoride, lithium fluoride, ammonium fluoride, sodium hydrogen fluoride, ammonium hydrogen fluoride, hexafluorosilicic acid, sodium hexafluorosilicate, and ammonium hexafluorosilicate. From the standpoints of availability and economy, component (a) is preferably one or more selected from hydrogen fluoride, sodium fluoride, potassium fluoride, lithium fluoride, ammonium fluoride, sodium hydrogen fluoride, and ammonium hydrogen fluoride, more preferably one or more selected from sodium fluoride, ammonium fluoride, and sodium hydrogen fluoride, and even more preferably sodium fluoride.

[0011] <Component (b)> The hard surface cleaning composition of the present invention contains an organic acid or a salt thereof as component (b). Component (b) has a synergistic effect with component (a) to enhance the performance of removing limescale stains. From the viewpoint of the performance of removing limescale stains, the acid dissociation constant (hereinafter referred to as pKa) of component (b) is preferably 4.6 or more, more preferably 5.0 or more, even more preferably 6.0 or more, and preferably 7.0 or less. The above-mentioned range of the acid dissociation constant may be any range that includes any one of the first acid dissociation constant (hereinafter referred to as pKa1), the second acid dissociation constant (hereinafter referred to as pKa2), and the third acid dissociation constant (hereinafter referred to as pKa3) of component (b).

[0012] From the viewpoint of ease of incorporation into the hard surface cleaner composition, component (b) is preferably a water-soluble organic acid or a salt thereof that can dissolve 5 g or more in 100 g of water at 20°C, and is preferably one or more selected from monocarboxylic acids, dicarboxylic acids, tricarboxylic acids, and salts thereof. Examples of organic acid salts of component (b) include alkali metal salts such as sodium and potassium, and alkaline earth metal salts such as calcium. Examples of monocarboxylic acids include propanoic acid (pKa: 4.87), lactic acid (pKa: 3.86), and butyric acid (pKa: 4.82). Examples of dicarboxylic acids include malic acid (pKa1: 3.46, pKa2: 5.10), tartaric acid (pKa1: 2.98, pKa2: 4.34), succinic acid (pKa1: 4.19, pKa2: 5.60), maleic acid (pKa1: 1.90, pKa2: 6.07), and malonic acid (pKa1: 2.83, pKa2: 5.29). Examples of tricarboxylic acids include citric acid (pKa1: 3.09, pKa2: 4.76, pKa3: 6.40).

[0013] From the viewpoint of the performance of removing water stains and the corrosion prevention performance of the hard surface cleaner composition, component (b) is preferably one or more selected from citric acid, propanoic acid, lactic acid, malic acid, tartaric acid, succinic acid, and salts thereof, more preferably one or more selected from citric acid, propanoic acid, malic acid, and salts thereof, and even more preferably citric acid or a salt thereof.

[0014] <Composition, etc.> In the hard surface detergent composition of the present invention, the content of component (a) is, in terms of fluorine atoms, 4 mM or more, preferably 6 mM or more, more preferably 7 mM or more, even more preferably 8 mM or more, still more preferably 10 mM or more, and still more preferably 35 mM or more, from the viewpoint of corrosion prevention, 240 mM or less, preferably 200 mM or less, more preferably 150 mM or less, and still more preferably 125 mM or less, and from the viewpoint of corrosion prevention and from the viewpoint of ensuring sufficient removal performance even on severe limescale stains, even more preferably 100 mM or less, and still more preferably 75 mM or less.

[0015] In the hard surface cleaner composition of the present invention, the content of component (b) is preferably 1% by mass or more, more preferably 2% by mass or more, and even more preferably 3% by mass or more from the viewpoint of limescale removal performance, and is preferably 15% by mass or less, more preferably 12% by mass or less, even more preferably 11% by mass or less, still more preferably 9% by mass or less, and still more preferably 7% by mass or less from the viewpoint of corrosion prevention. In the present invention, the mass of component (b) is expressed as an acid-equivalent value.

[0016] The hydrogen fluoride concentration in the hard surface cleaning composition of the present invention is 0.25 mM or more, preferably 0.30 mM or more, more preferably 0.40 mM or more, from the viewpoint of limescale removal performance, and 0.9 mM or less, preferably 0.80 mM or less, more preferably 0.70 mM or less, from the viewpoint of corrosion prevention. The hydrogen fluoride concentration [HF] in the hard surface cleaning composition of the present invention is calculated by the following (Equation 1): 7.08×10 －４ = [F － ][H ＋ ] / [HF] (Formula 1) [F － ]: the content (mM) of ionized fluorine in component (a) contained in the hard surface cleaning composition [H ＋ ]: hydrogen ion concentration (mM) calculated from the pH of the hard surface cleaning composition at 25 ° C. 7.08 × 10 －４ The acid ionization constant [HF] of hydrogen fluoride at 25°C is calculated by the following procedure when, for example, component (a) is sodium fluoride: 1. If the total amount of sodium fluoride blended in the hard surface cleaning composition is C mM, then C = [F － ] + [HF] 2, (Equation 1) C = [F － ] + [HF] introduced, 7.08 × 10 －４ = [F － ][H ＋ ] / [HF]=(C-[HF])[H ＋ ] / [HF] 3. Rearranging [HF], [HF] = C / (7.08 x 10 －４ / [H ＋ ] + 1) 4, C, and [H ＋ ] and calculate [HF]

[0017] From the viewpoints of water stain removal performance and ease of incorporation into hard surface detergent compositions, the hard surface detergent composition of the present invention may further contain, as component (c), one or more polymers selected from (c1) a carboxylic acid polymer containing a structural unit having a carboxyl group or a salt thereof (hereinafter referred to as component (c1)), and (c2) a sulfonic acid polymer containing a structural unit having a sulfonic acid group or a salt thereof (hereinafter referred to as component (c2)). From the viewpoints of water stain removal performance and ease of incorporation into hard surface detergent compositions, component (c1) is more preferred as component (c).

[0018] From the viewpoint of further improving the limescale removal performance and corrosion prevention performance, the carboxylic acid polymer of component (c1) is preferably at least one selected from polyacrylic acid, polymaleic acid, acrylic acid-maleic acid copolymer, and salts thereof, more preferably at least one selected from polyacrylic acid, acrylic acid-maleic acid copolymer, and salts thereof. The salt may be a partial or complete salt, and is preferably an alkali metal salt, more preferably a sodium salt or potassium salt.

[0019] From the viewpoints of limescale removal performance and easy-to-use liquid properties, the weight-average molecular weight of the carboxylic acid polymer of component (c1) is preferably at least 500, more preferably at least 1000, even more preferably at least 1500, and preferably at most 300000, more preferably at most 200000, even more preferably at most 100000, and still more preferably at most 60000. The weight-average molecular weight of the carboxylic acid polymer is measured by gel permeation chromatography (GPC) using polyethylene glycol of known molecular weight as a standard substance.

[0020] Examples of the sulfonic acid polymer of component (c2) include aromatic formalin condensates containing aromatic sulfonic acids or salts thereof, and salts thereof. Among these, examples of aromatic sulfonic acids include petroleum sulfonic acid, naphthalene sulfonic acid, lignin sulfonic acid, creosote oil sulfonic acid, and cresol alkylene sulfonic acid. Specific examples of sulfonic acid polymers include metacresol methylene sulfonic acid-Schaeffer acid formalin condensate salts (such as Kao Corporation's "Demol SSL" (registered trademark)), metacresol methylene sulfonic acid formalin condensate salts (such as Kao Corporation's "Demol SC30" (registered trademark)), creosote oil sulfonic acid formalin condensate salts (such as Kao Corporation's "Demol C" (registered trademark)), naphthalene sulfonic acid formalin condensate salts (such as Kao Corporation's "Demol NL" (registered trademark)), lignin sulfonic acid formalin condensate salts, melamine sulfonic acid formalin condensate salts, and sodium styrene sulfonate polymer salts. From the viewpoint of limescale removal performance, the sulfonic acid polymer is preferably naphthalene sulfonic acid formalin condensate or its salt.

[0021] From the viewpoints of removal performance and easy-to-use liquid properties, the weight-average molecular weight of the sulfonic acid polymer of component (c2) is preferably at least 500, more preferably at least 1000, even more preferably at least 1500, and preferably at most 300000, more preferably at most 200000, even more preferably at most 100000, and still more preferably at most 60000. The weight-average molecular weight of the sulfonic acid polymer is measured by gel permeation chromatography (GPC) using polyethylene glycol of known molecular weight as a standard substance.

[0022] When the hard surface detergent composition of the present invention contains component (c), the content of component (c) in the hard surface detergent composition of the present invention is, from the viewpoint of water stain removal performance, preferably 0.1 mass % or more, more preferably 0.3 mass % or more, even more preferably 0.5 mass % or more, and from the viewpoint of obtaining suitable liquid properties, for example, from the viewpoint of obtaining suitable liquid properties required when spraying or applying to an object using a spray means, preferably 10 mass % or less, more preferably 5 mass % or less, even more preferably 3 mass % or less.

[0023] From the viewpoint of further enhancing the performance of removing water stains, the hard surface cleaning composition of the present invention can further contain a surfactant as component (d). The surfactant for component (d) can be one or more selected from (d1) anionic surfactant (hereinafter also referred to as component (d1)), (d2) nonionic surfactant (hereinafter also referred to as component (d2)), (d3) amphoteric surfactant (hereinafter also referred to as component (d3)), and (d4) cationic surfactant (hereinafter also referred to as component (d4)). From the viewpoint of ease of incorporation into the hard surface cleaning composition, one or more selected from anionic surfactants, nonionic surfactants, and amphoteric surfactants are preferred, and amphoteric surfactants are more preferred.

[0024] Examples of the anionic surfactant of component (d1) include one or more selected from alkylbenzenesulfonates, polyoxyalkylene alkyl or alkenyl ether sulfate salts, alkyl or alkenyl sulfate salts, olefinsulfonates, alkanesulfonates, saturated or unsaturated fatty acid salts, alkyl or alkenyl ether carboxylate salts, α-sulfofatty acid salts, N-acylamino acids, mono- or diester phosphates, and sulfosuccinate esters. The carbon number of the alkyl or alkenyl group of the anionic surfactant is, for example, 8 to 22 carbon atoms, preferably 10 to 16 carbon atoms, and more preferably 12 to 14 carbon atoms. The polyoxyalkylene group of the anionic surfactant is preferably one or more groups selected from oxyethylene groups and oxypropylene groups, with oxyethylene groups being preferred. The average number of moles of oxyalkylene groups added in the polyoxyalkylene group is, for example, 0 to 10, preferably 1 to 3. Counter ions of the anionic groups of these anionic surfactants include alkali metal ions such as sodium ions and potassium ions; alkaline earth metal ions such as calcium ions and magnesium ions; ammonium ions; and alkanolamines having 1 to 3 alkanol groups each having 2 or 3 carbon atoms (for example, monoethanolamine, diethanolamine, triethanolamine, triisopropanolamine, etc.).

[0025] From the viewpoint of economy, the anionic surfactant of component (d1) is preferably one or more selected from alkylbenzenesulfonates, alkyl or alkenyl ether sulfates, and alkyl or alkenyl sulfates, and from the viewpoint of limescale removal performance, alkyl or alkenyl ether sulfates are more preferred. From the viewpoint of ease of incorporation into hard surface detergent compositions, the number of carbon atoms in the alkyl group of the alkylbenzenesulfonate is 10 or more, preferably 12 or more, and 18 or less, preferably 14 or less, and the alkyl group is preferably linear. The alkyl or alkenyl ether sulfate is preferably a polyoxyalkylene alkyl or alkenyl ether sulfate. From the viewpoint of ease of incorporation into hard surface detergent compositions, the polyoxyalkylene alkyl or alkenyl ether sulfate has an alkyl or alkenyl group having 8 or more, preferably 10 or more, and 18 or less, preferably 14 or less, carbon atoms. The polyoxyalkylene alkyl or alkenyl ether sulfate salt has an oxyalkylene group having preferably 2 or 3 carbon atoms, more preferably 2, and an average number of moles of oxyalkylene groups added of 0.5 or more, preferably 1.0 or more, and 4.0 or less, preferably 3.0 or less. From the viewpoint of ease of incorporation into a hard surface cleaner composition, the alkyl or alkenyl group of the alkyl or alkenyl sulfate salt has an alkyl or alkenyl group having 10 or more carbon atoms, preferably 12 or more, and 18 or less, preferably 14 or less.

[0026] Examples of the nonionic surfactant of component (d2) include one or more selected from polyoxyalkylene alkyl ethers, polyoxyalkylene alkenyl ethers, polyoxyalkylene sorbitan fatty acid esters, alkyl glycosides, alkyl polyglycosides, sucrose fatty acid esters, and alkyl polyglyceryl ethers. 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. The alkylene oxide in the polyoxyalkylene alkyl ether, polyoxyalkylene alkenyl ether, or polyoxyalkylene sorbitan fatty acid ester preferably includes an alkylene oxide selected from ethylene oxide and propylene oxide, and the average number of moles of alkylene oxide added is preferably 2 or more, and preferably 25 or less.

[0027] From the viewpoint of water stain removal performance, the component (d2) is preferably a nonionic surfactant represented by the following general formula (d2): ２１ｄ (CO) ｍ O-(A ２１ｄ O) ｎ -R ２２ｄ (d2) [wherein, R ２１ｄ is an aliphatic hydrocarbon group having 8 to 18 carbon atoms, and R ２２ｄ is a hydrogen atom or a methyl group. CO is a carbonyl group, and m is the number 0 or 1. A ２１ｄ The group is an alkyleneoxy group containing an ethyleneoxy group and having 2 to 4 carbon atoms, and n is the average number of moles added, which is a number of 1 to 30.

[0028] In general formula (d2), R ２１ｄ From the viewpoint of ease of incorporation into a hard surface cleaning composition, the number of carbon atoms in R is 8 or more, preferably 10 or more, more preferably 12 or more, and 18 or less, preferably 16 or less, more preferably 14 or less. ２１ｄ is an aliphatic hydrocarbon group, preferably a group selected from alkyl groups and alkenyl groups.

[0029] In general formula (d2), A ２１ｄThe O group is an alkyleneoxy group containing an ethyleneoxy group and having 2 to 4 carbon atoms, preferably an alkyleneoxy group containing an ethyleneoxy group and having 2 to 3 carbon atoms, and more preferably an ethyleneoxy group. ２１ｄ The O group may be an alkyleneoxy group, including an ethyleneoxy group and another alkyleneoxy group, such as a propyleneoxy group. The other alkyleneoxy group is preferably a propyleneoxy group. ２１ｄ When the O group contains an ethyleneoxy group and a propyleneoxy group, the ethyleneoxy group and the propyleneoxy group may be bonded in a block or random manner.

[0030] In the general formula (d2), n is A ２１ｄ It is the average number of moles of O groups added, and is a number of 1 to 30. In general formula (d2), n is 1 or more, preferably 6 or more, more preferably 10 or more, and 30 or less, preferably 25 or less, more preferably 20 or less, from the viewpoint of ease of incorporation into a detergent composition for hard surfaces.

[0031] Examples of the amphoteric surfactant of component (d3) include one or more selected from alkyldimethylamine oxide, alkyldimethylaminoacetic acid betaine, alkylhydroxysulfobetaine, alkylamidopropyl betaine, and alkylcarboxymethylhydroxyethylimidazolium betaine.

[0032] As the amphoteric surfactant of component (d3), a compound of the following general formula (d3) is preferred from the viewpoints of water stain removal performance and obtaining favorable foam characteristics when sprayed or applied to an object using a spray means.

[0033]

[0034] [In the formula, R ３１ｄ is an alkyl or alkenyl group having 7 to 18 carbon atoms, and R ３２ｄ is an alkylene group having 1 to 6 carbon atoms. A is a group selected from -COO-, -CONH-, -OCO-, -NHCO-, and -O-, and r is the number 0 or 1. R ３３ｄ , R ３４ｄis an alkyl group or a hydroxyalkyl group having 1 to 3 carbon atoms, and R ３５ｄ is an alkylene group having 1 to 5 carbon atoms which may be substituted with a hydroxy group. B is —SO ３ － , -OSO ３ － , -COO － It is.

[0035] In general formula (d3), R ３１ｄ is an alkyl or alkenyl group, preferably an alkyl group, having 7 or more, preferably 10 or more, and 18 or less, preferably 14 or less, more preferably 12 or less carbon atoms, from the viewpoint of ease of incorporation into a detergent composition for hard surfaces. A is preferably -COO- or -CONH-, more preferably -CONH-. R ３２ｄ The number of carbon atoms in R is preferably 2 or 3. r is preferably 0. ３３ｄ , R ３４ｄ is preferably a methyl group. ３５ｄ is preferably a hydroxyalkyl group having 3 carbon atoms. B is preferably —SO ３ － is.

[0036] Examples of the cationic surfactant of component (d4) include one or more selected from alkyltrimethylammonium salts in which the alkyl group has 8 to 22 carbon atoms, dialkyldimethylammonium salts in which the alkyl group has 8 to 22 carbon atoms, alkyldimethylbenzylammonium salts in which the alkyl group has 8 to 22 carbon atoms, and benzethonium salts. Examples of the salt include halogen salts and alkyl sulfates in which the carbon number is 1 to 3.

[0037] When the hard surface cleaning composition of the present invention contains component (d), the content of component (d) in the hard surface cleaning composition of the present invention is preferably 0.3 mass% or more, more preferably 0.6 mass% or more, even more preferably 1 mass% or more, and preferably 7 mass% or less, more preferably 5 mass% or less, even more preferably 3 mass% or less, from the viewpoints of economy, the stability of the composition over time, the limescale removal performance, and ease of incorporation into the composition. In the present invention, when component (d1) is included as component (d), the mass of component (d1) is expressed as a value converted into a sodium salt. Furthermore, when component (d4) is included as component (d), the mass of component (d4) is expressed as a value converted into a chlorine salt.

[0038] From the viewpoint of further improving the performance of removing water stains, the hard surface cleaning composition of the present invention may further contain a water-soluble solvent as component (e). With respect to component (e), "water-soluble" means that 5 g or more of the component (e) dissolves in 100 g of water at 20°C.

[0039] Examples of the water-soluble solvent for component (e) include one or more water-soluble solvents selected from ethanol, isopropyl alcohol, 2-methyl-2-propanol, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, diethylene glycol monohexyl ether, propylene glycol monoethyl ether (methylpropylene glycol), propylene glycol monopropyl ether, propylene glycol monobutyl ether, propylene glycol monohexyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monopropyl ether, dipropylene glycol monobutyl ether, triethylene glycol monobutyl ether, 3-methyl-3-methoxybutanol, and dibutylene diglycol. From the viewpoint of further improving the limescale removal performance, component (e) is more preferably one or more water-soluble solvents selected from diethylene glycol monobutyl ether, diethylene glycol monopropyl ether, and propylene glycol monohexyl ether.

[0040] When the hard surface detergent composition of the present invention contains component (e), the content of component (e) in the hard surface detergent composition of the present invention is, from the viewpoint of limescale stain removal performance, preferably 0.1 mass % or more, more preferably 0.5 mass % or more, even more preferably 1 mass % or more, and, from the viewpoint of economy, preferably 15 mass % or less, more preferably 10 mass % or less, even more preferably 7 mass % or less.

[0041] The hard surface cleaning composition of the present invention may optionally contain a chelating agent, a fragrance, a colorant, a preservative, an enzyme, a pH adjuster, an antioxidant, etc. in order to increase the added value of the product (however, excluding the above components (a) to (e)).

[0042] The hard surface detergent composition of the present invention can achieve both water stain removal performance and corrosion prevention for hard surfaces without containing a corrosion inhibitor. Examples of the corrosion inhibitor include one or more selected from aluminates, gluconates, aluminum salts, borax, and zinc salts. From the viewpoints of economy and stability over time of the composition, the content of the corrosion inhibitor in the hard surface detergent composition of the present invention is preferably 5% by mass or less, more preferably 3% by mass or less, and even more preferably 1% by mass or less. The hard surface detergent composition of the present invention does not need to contain a corrosion inhibitor.

[0043] The hard surface cleaning composition of the present invention contains water. That is, the balance other than the components (a) and (b) and any optional components is water. The hard surface cleaning composition of the present invention contains water in an amount of preferably 60% by mass or more, more preferably 65% ​​by mass or more, even more preferably 70% by mass or more, and preferably 97% by mass or less, more preferably 95% by mass or less, even more preferably 93% by mass or less. It is preferable to use ion-exchanged water, sterilized ion-exchanged water, etc. as the water.

[0044] The pH of the hard surface cleaning composition of the present invention at 25°C is 4.0 or more, preferably 4.5 or more, more preferably 4.8 or more, and 6.5 or less, preferably 6.0 or less, more preferably 5.5 or less, from the viewpoints of water stain removal performance and corrosion prevention. The pH is a value measured by the glass electrode method. The pH of the hard surface cleaning composition of the present invention at 25°C is specifically measured by the pH measurement method described below.

[0045] <pH Measurement Method> A pH measurement composite electrode (HORIBA, glass ground sleeve type) is connected to a pH meter (HORIBA, pH / ion meter F-23) and the power is turned on. A saturated potassium chloride aqueous solution (3.33 mol / L) is used as the internal solution of the pH electrode. Next, a pH 6.86 standard solution (neutral phosphate standard solution), a pH 9.18 standard solution (borate standard solution), and a pH 12.0 standard solution (saturated calcium hydroxide standard solution) are each filled into a 100 mL beaker and immersed in a thermostatic bath at 25°C for 30 minutes. The pH measurement electrode is immersed in the thermostatically adjusted standard solution for 3 minutes, and calibration is performed in the order of pH 6.86 → pH 9.18 → pH 12.0. The sample to be measured (the cleaning composition for hard surfaces of the present invention) is adjusted to 25°C, and the electrode of the pH meter is immersed in the sample, and the pH is measured after 1 minute.

[0046] The hard surfaces targeted by the hard surface cleaner composition of the present invention may be tile, glass, metal (stainless steel, aluminum alloy, etc.), plastic, or ceramic hard surfaces. The hard surface cleaner composition of the present invention is suitably used for cleaning hard surfaces such as bathrooms, bathtubs, washbasins, tiles, restrooms, washstands, mirrors, kitchen sinks, countertops, and areas around water supplies. It is suitably used for bathrooms. Here, "for bathrooms" refers not only to bathrooms but also to other items with hard surfaces present in the bathroom, such as bathtubs and washbasins. The present invention is preferably targeted at hard surfaces with limescale stains attached.

[0047] The hard surface detergent composition of the present invention is preferably used by spraying or applying it in the form of droplets or foam and bringing it into contact with a hard surface. A spray means can be used for spraying or applying it. The present invention provides a spray-container-packed hard surface detergent article, which is obtained by filling the hard surface detergent composition of the present invention into a container equipped with a sprayer.

[0048] In the spray-container-packaged hard surface cleaner article of the present invention, the container equipped with a sprayer into which the hard surface cleaner composition of the present invention is filled includes manual spray devices that do not use a propellant, such as trigger-type spray containers and pump-type spray containers, and aerosols that use a propellant. The container equipped with the sprayer is preferably a trigger-type spray that can spray or apply the contents in the form of droplets or foam, and more preferably a trigger-type spray equipped with a mechanism for spraying the contents in the form of droplets or a mechanism for forming foam (foam-forming mechanism).

[0049] When a trigger-type spray equipped with a mechanism for spraying the hard surface cleaner composition of the present invention in the form of droplets is used in the spray-bottled hard surface cleaner article of the present invention, the nozzle diameter of the spray container containing the composition is preferably 0.1 mm or more, more preferably 0.3 mm or more, and preferably 2 mm or less, more preferably 1 mm or less, so as to facilitate spraying, to prevent the sprayed droplets from being rough, not sprayed in a straight line, and to prevent the spray area from becoming extremely narrow. When a trigger-type spray equipped with a mechanism for spraying in the form of droplets is used, the spray-bottled hard surface antifungal article of the present invention sprays preferably 0.1 mL or more, more preferably 0.3 mL or more, and preferably 5 mL or less, more preferably 2 mL or less of the composition in one operation.

[0050] Furthermore, when a trigger-type spray equipped with a foam-forming mechanism is used in the spray-container-packaged hard-surface cleaner article of the present invention, the spray-container-packaged hard-surface cleaner article preferably has a spin element and a liquid passage plate having several rod-shaped protrusions disposed in a circular space having a diameter of 4 to 8 mm. Here, the spin element is a mechanism that imparts spin to a liquid flow through the spin element and finally sprays the liquid from a nozzle. For detailed structures thereof, reference can be made to Figure 4(b) of JP-A-8-332422 and JP-A-8-108102, Figure 1 of JP-A-2002-68265, etc.

[0051] When using a trigger-type spray equipped with a foam-forming mechanism, the spray-container hard surface cleaner article of the present invention sprays, in one operation, preferably 0.5 mL or more, more preferably 1 mL or more, and preferably 30 mL or less, more preferably 15 mL or less, and even more preferably 5 mL or less of the composition.

[0052] The liquid passage plate, another component of the foam-forming mechanism, has preferably 3 to 8 rod-shaped protrusions disposed in a circular space having a diameter of 5 to 7 mm, and when viewed from above, the rod-shaped protrusions are preferably rectangular, having a width of 0.8 to 1.2 mm and a length of 2 to 4 mm. Furthermore, the area occupied by the rod-shaped protrusions relative to the space excluding the rod-shaped protrusions is preferably 30% or more, more preferably 40% or more, and preferably 90% or less, more preferably 80% or less, and even more preferably 70% or less. By providing such a liquid passage plate, the adhesion and retention of foam on vertical surfaces is improved.

[0053] The container of the spray-container hard surface cleaner article of the present invention can be a commonly used container. For example, it can be made from polyethylene, polypropylene, or polyethylene terephthalate, and can be manufactured by blow molding or the like. The thickness of the container may differ between the bottom and sides, and is preferably 0.01 to 2 mm, and the container capacity is preferably 100 to 1000 mL. For ease of handling, the amount of hard surface cleaner composition filled into the container is preferably 200 to 500 mL. Furthermore, the liquid is filled while leaving a reasonable amount of space.

[0054] [Method for cleaning hard surfaces] The present invention provides a method for cleaning hard surfaces, which comprises contacting the hard surface with the hard surface detergent composition of the present invention for a predetermined period of time, and then rinsing the hard surface with water. Furthermore, the present invention provides a method for removing water stains, which comprises contacting the hard surface with the hard surface detergent composition of the present invention for a predetermined period of time, and then rinsing the hard surface with water. That is, the method for removing water stains from a hard surface comprises contacting the hard surface with the hard surface detergent composition of the present invention for a predetermined period of time, and then rinsing the hard surface with water. The matters described for the hard surface detergent composition of the present invention can be applied to these methods as appropriate. Preferred aspects of the composition are also the same as those for the hard surface detergent composition of the present invention described above. The target hard surface is the same as that described for the hard surface detergent composition of the present invention.

[0055] In the hard surface cleaning method of the present invention, the hard surface detergent composition is contacted with the hard surface. Specifically, the hard surface detergent composition is contacted with the hard surface in its undiluted form, or the hard surface detergent composition is contacted with the hard surface in its undiluted form, i.e., the hard surface detergent composition is contacted with the hard surface without dilution. Contacting the hard surface detergent composition with the hard surface without dilution means that the hard surface detergent composition is not contacted with the hard surface after intentionally diluting it with water or the like. For example, when the hard surface detergent composition is contacted with a hard surface to which water droplets or the like have adhered, or when water droplets adhere to the hard surface after contacting the hard surface with the hard surface detergent composition, the hard surface detergent composition can be understood as being contacted with the hard surface without dilution. In the present invention, it is preferable to contact the undiluted hard surface detergent composition with the hard surface as is, i.e., without changing the composition. For example, the hard surface cleaning composition is brought into contact with a hard surface without being attached to a wet sponge. After contacting the hard surface, the composition of the hard surface cleaning composition may change. That is, after contacting the hard surface, the composition of the hard surface cleaning composition may be diluted or concentrated.

[0056] The method for contacting the hard surface detergent composition with the hard surface is preferably spraying or applying, more preferably spraying in the form of droplets or applying in the form of foam. The method for cleaning a hard surface of the present invention preferably uses the above-mentioned spray-container-packaged hard surface detergent article of the present invention.

[0057] In the method for cleaning a hard surface of the present invention, the cleaning composition for hard surfaces is applied to an area of ​​100 cm of the hard surface to be cleaned. ２ The amount of the cellulose is preferably 0.1 g or more, more preferably 0.3 g or more, even more preferably 0.4 g or more, and preferably 5 g or less, more preferably 3 g or less, even more preferably 2 g or less.

[0058] The time for which the hard surface cleaning composition of the present invention is allowed to stand after contacting the hard surface with the composition is preferably 1 minute or more, preferably 2 minutes or more, more preferably 3 minutes or more, even more preferably more than 3 minutes, still more preferably 4 minutes or more, and even more preferably 5 minutes or more, from the viewpoint of detergency, and is preferably 60 minutes or less, more preferably 30 minutes or less, even more preferably 15 minutes or less, and still more preferably 10 minutes or less, from the viewpoint of efficient cleaning. In this case, the time when the composition first comes into contact with the hard surface may be considered the start of the standing period. The temperature during standing may be room temperature, for example, 10°C or more and 30°C or less.

[0059] Furthermore, in the present invention, hard surfaces can be cleaned using a cleaning article having a substrate impregnated with the hard surface detergent composition of the present invention. As an example, a method for cleaning hard surfaces is provided in which the hard surface detergent composition of the present invention is applied to a hard surface, left for a predetermined time, and then wiped off. For wiping, it is preferable to use a cloth, dustcloth, nonwoven fabric, etc. to remove the composition applied to the hard surface from the hard surface.

[0060] The substrate used for the cleaning article impregnated with the hard surface detergent composition is one that is flexible, can be impregnated with the hard surface detergent composition, has sufficient strength during use, and does not generate debris, etc. It is preferable to use a substrate that can be impregnated with the hard surface detergent composition in an amount described below under no load.

[0061] Examples of such substrates include fiber structures made of fibrous materials, such as various types of paper, nonwoven fabrics, woven fabrics, and knitted fabrics. Examples of the fibrous materials that make up these fiber structures include cellulosic fibers, modified cellulosic fibers, synthetic fibers, and mixtures of two or more of these. Porous structures (e.g., sponge-like structures) obtained by dispersing air bubbles in a resin can also be used as the substrate.

[0062] Furthermore, a cleaning method in which a cleaning article impregnated with the hard surface detergent composition of the present invention is used to wipe a hard surface is preferred for light cleaning of hard surfaces from the viewpoint of workability of the cleaning work. The cleaning article impregnated with the hard surface detergent composition may be one in which a substrate is pre-impregnated with the detergent composition, or one in which a dried substrate is impregnated with the hard surface detergent composition immediately before use. Furthermore, the cleaning article impregnated with the hard surface detergent composition may be attached to a mop-like cleaning tool or may be held directly by hand and used for wiping.

[0063] In the present invention, the hard surface cleaning composition of the present invention is brought into contact with the hard surface and left for a predetermined time, and then, after further washing as necessary, the hard surface is rinsed with water. When rinsing, an external force (physical force) such as hand washing may be applied, or the hard surface may simply be rinsed with a water stream.

[0064] Examples The components used in the examples and comparative examples are as follows: <Component (a)> NaF: sodium fluoride, manufactured by Sunlit Fluo & Chemical Co., Ltd. NH ４ F: Ammonium fluoride, manufactured by GIN JOB ENTEPRISECo., Ltd. / CHINAG MAU Co., Ltd. ・NaHF ２: Sodium hydrogen fluoride, manufactured by GIN JOB ENTEPRISECo., Ltd. / CHINAG MAU Co., Ltd. <Component (b)> Citric acid: Citric acid, manufactured by SunlitFluo & Chemical Co., Ltd. Propanoic acid: Propanoic acid, manufactured by Tokyo Chemical Industry Co., Ltd. Lactic acid: Lactic acid, manufactured by Corbion Malic acid: Malic acid, manufactured by FusoChemical Co., Ltd. Tartanic acid: Tartaric acid, manufactured by Combi-Blocks Succinic acid: Succinic acid, manufactured by Tokyo Chemical Industry Co., Ltd.

[0065] <Component (c)> Acusol 445N: polyacrylic acid sodium salt, weight average molecular weight 4500, component (c1), manufactured by Dow Chemical Company DEMOL N: naphthalenesulfonic acid formalin condensate sodium salt, weight average molecular weight 5000, component (c2), manufactured by Kao Corporation FK-6H: diallyldimethylammonium chloride-maleic acid-sulfur dioxide copolymer, weight average molecular weight 23000, component (c1), manufactured by Nittobo Medical Co., Ltd. Sokalan CP88: acrylic acid-maleic acid copolymer sodium salt, weight average molecular weight 3000, component (c1), manufactured by BASF Co., Ltd. Sokalan CP7: acrylic acid-maleic acid copolymer sodium salt, weight average molecular weight 50000, component (c1), manufactured by BASF Co., Ltd. Acusol 469N: acrylic acid-maleic acid copolymer, weight average molecular weight 45,000, component (c1), manufactured by Dow Chemical Company. OLIGOMER KDS: sodium salt of acrylic acid-maleic acid copolymer, weight average molecular weight 2,000, component (c1), manufactured by Kao Corporation.

[0066] <Component (d)> Amphitol 20AB: lauric acid amidopropyl betaine, component (d3), manufactured by Kao Corporation. AS: ammonium lauryl sulfate, "EMAL AD-25", component (d1), manufactured by Kao Taiwan Co., Ltd. AES (EO2): polyoxyethylene (2) sodium lauryl ether sulfate (the average number of moles of oxyethylene groups added in parentheses is "EMAL 227HP", component (d1), manufactured by Kao Corporation. LAS: sodium alkylbenzene sulfonate, "NEOPELEX S-N", component (d1), manufactured by Kao Taiwan Co., Ltd. AEO (EO10): polyoxyethylene adduct of natural alcohol (the average number of moles of oxyethylene groups added is 10), "Pannox 710", component (d2), manufactured by PAN ASIA CHEMICAL Co., Ltd. Amphitol 20HD: Lauryl hydroxysulfobetaine, component (d3), manufactured by Kao Corporation <Component (e)> BDG: Diethylene glycol monobutyl ether, manufactured by BASF Co., Ltd.

[0067] [Preparation of Cleaning Compositions for Hard Surfaces] Using the components shown in Tables 1 to 5, cleaning compositions for hard surfaces having the compositions shown in Tables 1 to 5 were prepared by the method described below. To obtain the cleaning compositions for hard surfaces shown in Tables 1 to 5, first, components (a) to (e) were added to ion-exchanged water in the amounts shown in Tables 1 to 5, and dissolved at room temperature (25°C). After blending, hydrochloric acid and / or sodium hydroxide was added as a pH adjuster to adjust the pH to the value shown in Tables 1 to 5. The pH was measured by the glass electrode method. The contents of each component in Tables 1 to 5 are all effective amounts. The content of component (a) is also shown in the tables as the content in terms of fluorine atoms.

[0068] [Hydrogen fluoride concentration in hard surface cleaning composition] The hydrogen fluoride concentration [HF] in each hard surface cleaning composition was calculated using the following (Equation 1). The results are shown in Tables 1 to 5. －４ = [F － ][H ＋ ] / [HF] (Formula 1) [F －]: the content (mM) of ionized fluorine in component (a) contained in the hard surface cleaning composition [H ＋ ]: hydrogen ion concentration (mM) calculated from the pH of the hard surface cleaning composition at 25 ° C. 7.08 × 10 －４ The acid ionization constant [HF] of hydrogen fluoride at 25°C is calculated by the following procedure when, for example, component (a) is sodium fluoride: 1. If the total amount of sodium fluoride blended in the hard surface cleaning composition is C mM, then C = [F － ] + [HF] 2, (Equation 1) C = [F － ] + [HF] introduced, 7.08 × 10 －４ = [F － ][H ＋ ] / [HF]=(C-[HF])[H ＋ ] / [HF] 3. Rearranging [HF], [HF] = C / (7.08 x 10 －４ / [H ＋ ] + 1) 4, C, and [H ＋ ] and calculate [HF]

[0069] [Evaluation of Water Scale Cleaning Ability] Preparation of Water Scale-Laden Glass Plates for Evaluation Water scale-laden glass plates for evaluation were prepared according to the following procedure. 1. 1000 ml of tap water from Hsinchu, Taiwan was placed in a beaker, and concentrated to a volume of 250 ml while heating with a panel heater, and then cooled at room temperature. 2. 0.5 ml of the solution prepared in step 1 was dropped onto a 2 x 10 cm soda-lime glass plate (microscope slide CAT. NO. 7101, SAIL BRAND), and then the water was evaporated while heating with a heater. 3. Step 2 was repeated eight times, and then the plate was left for three days to prepare a water scale-laden glass plate.

[0070] Evaluation Method for Limescale Stain Cleaning Ability The evaluation of limescale stain cleaning ability was performed according to the following procedure. 1. First, a cellulose fiber (2.5 x 2.0 cm, product name: Laune Facial Puff, KNH Enterprise Co., Ltd.) was placed on the limescale-stained glass plate to prevent dripping, and 200 μl of each hard surface cleaner composition shown in Tables 1 to 5 was dropped onto the cellulose fiber. 2. After leaving it for 3 minutes, the cellulose fiber was removed. 3. Next, as a scrubbing step, a kitchen paper with a 250 g weight was run back and forth across the surface three times. 4. The glass plate before limescale staining and the limescale-stained glass plate before and after cleaning were scanned with a printer (IMC2500, Ricoh Co., Ltd.), the gray values ​​were measured, and the limescale stain cleaning rate was calculated using the image processing software "Image J" according to the following formula. The results are shown in Tables 1 to 5. Cleaning power (%) = (Ga - Gb) / (G - Gb) x 100 Gb: Average gray value of glass plate with water stains before cleaning Ga: Average gray value of glass plate with water stains after cleaning G: Average gray value of glass plate before water stains

[0071] [Corrosion Test] The same cellulose fiber (2.5 x 2.0 cm, product name: Laune Facial Puff, KNH Enterprises Co., Ltd.) as described above was placed on evaluation plates made of soda-lime glass plates (microscope slide CAT. No. 7101, SAIL BRAND) and aluminum alloy plates (supplied by a hardware store in Taiwan). 500 μl of each hard surface cleaner composition shown in Tables 1 to 5 was dropped onto the plates. After waiting for 24 hours, the surfaces of the evaluation plates were visually observed and rated according to the following criteria. The results are shown in Tables 1 to 5. For evaluation criteria other than evaluation criteria 1, the evaluation result of the composition of Example 1 was rated as 4, the evaluation result of the composition of Comparative Example 2 was rated as 2, and the results were visually evaluated on a 5-point scale between these. (Evaluation Criteria) 4: No change on the surface of the evaluation plate. 3-4: Very slight discoloration on the surface of the evaluation plate. 3: Slight discoloration on the surface of the evaluation plate. 2-3: Somewhat slight discoloration on the surface of the evaluation plate. 2: The surface of the evaluation board is discolored. 1: The surface of the evaluation board is uneven.

[0072]

[0073]

[0074]

[0075]

[0076]

Claims

1. A hard surface cleaning composition comprising (a) a fluoride (hereinafter referred to as component (a)) and (b) an organic acid or a salt thereof (hereinafter referred to as component (b)), the content of component (a) being 4 mM or more and 240 mM or less in terms of fluorine atoms, the pH at 25°C being 4.0 or more and 6.5 or less, and the hydrogen fluoride concentration [HF] in the hard surface cleaning composition calculated by the following (formula 1) being 0.25 mM or more and 0.9 mM or less. －４ = [F － ][H ＋ ] / [HF] (Formula 1) [F － ]: the ionized fluorine content (mM) in the component (a) contained in the hard surface cleaning composition [H ＋ ]: Hydrogen ion concentration (mM) calculated from the pH of the hard surface cleaning composition at 25 ° C. 7.08 × 10 －４ : Acid ionization constant of hydrogen fluoride at 25°C 2. The cleaning composition for hard surfaces according to claim 1, wherein component (a) is one or more selected from hydrogen fluoride, sodium fluoride, potassium fluoride, lithium fluoride, ammonium fluoride, sodium hydrogen fluoride, and ammonium hydrogen fluoride.

3. A cleaning composition for hard surfaces according to claim 1 or 2, wherein component (b) is an organic acid having a carboxy group.

4. The hard surface cleaning composition according to any one of claims 1 to 3, wherein component (b) is one or more selected from the group consisting of citric acid, propanoic acid, lactic acid, malic acid, tartaric acid, and succinic acid.

5. A cleaning composition for hard surfaces described in any one of claims 1 to 4, wherein the content of component (b) is 1 mass% or more and 15 mass% or less.

6. The hard surface cleaning composition according to any one of claims 1 to 5, further comprising, as component (c), one or more polymers selected from (c1) a carboxylic acid-based polymer containing a structural unit having a carboxyl group or a salt thereof (hereinafter referred to as component (c1)), and (c2) a sulfonic acid-based polymer containing a structural unit having a sulfonic acid group or a salt thereof (hereinafter referred to as component (c2)).

7. The cleaning composition for hard surfaces according to claim 6, wherein the component (c) is component (c1).

8. A cleaning composition for hard surfaces according to claim 6 or 7, wherein the content of component (c) is 0.1 mass% or more and 10 mass% or less.

9. The cleaning composition for hard surfaces according to any one of claims 1 to 8, further comprising a surfactant as component (d).

10. The hard surface cleaning composition according to claim 9, wherein component (d) is one or more selected from anionic surfactants, nonionic surfactants, and amphoteric surfactants.

11. A method for cleaning a hard surface, comprising contacting the hard surface with the cleaning composition for hard surfaces according to any one of claims 1 to 10 for a predetermined period of time, and then rinsing the hard surface with water.

12. The method of cleaning a hard surface according to claim 11, wherein the predetermined period of time is greater than or equal to one minute.

13. The method for cleaning a hard surface according to claim 11 or 12, wherein the hard surface is a hard surface having water stains.

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