Washing liquid and washing method

Abstract

According to the invention, a cleaning solution containing a solvent and a metal remover is adopted. The cleaning solution contains two or more solvents, and the distance (HSP distance) between the Hansen solubility parameter of the cleaning solution and the Hansen solubility parameter of dimethylacetamide is 1.0 or less. The total content of an organic substance selected from the group consisting of an organic acid polymer, an organic acid ester, and a ketone body is from 0.1 * 10 <-9 > parts by mass to 105 * 10 <-6 > parts by mass (inclusive) per 100 parts by mass of the total of the solvent and the metal remover. According to the washing liquid, the removal performance of organic impurity dirt can be improved.

Description

Technical Field

[0001] This invention relates to a washing liquid and a washing method.

[0002] This application claims priority based on Japanese Patent Application No. 2023-187034, filed in Japan on October 31, 2023, the contents of which are incorporated herein by reference. Background Technology

[0003] The choice of detergent depends on the type of dirt and the material of the object being washed.

[0004] In the industrial field, for example in membranes made of polymer materials, especially porous membranes, the effects of organic contamination such as polymer residues from the polymer materials used in the membrane manufacturing process, or metallic contamination such as from metal catalysts, can become a problem.

[0005] To address this issue, a membrane cleaning solution with a specific solvent selected based on the membrane material was proposed (see Patent Document 1).

[0006] Existing technical documents Patent documents Patent Document 1: Japanese Patent Application Publication No. 2017-202479 Summary of the Invention

[0007] The problem that the invention aims to solve Previously, in filters made of porous membranes, the purified pharmaceutical solutions sometimes became contaminated, contrary to their intended purpose. The sources of contamination were high- or low-molecular-weight organic impurities or metallic impurities coexisting in the filter. Organic impurities not only originated from the polymer materials forming the components but also easily entered from various parts of the production line, such as piping, containers, and equipment. On the other hand, with the miniaturization and high performance of industrial products, there is a strong demand for further reduction of such organic impurities.

[0008] The present invention was made in view of the above circumstances, and its object is to provide a washing liquid with improved removability of organic impurities and dirt, and a washing method using the washing liquid.

[0009] Methods for solving problems To address the aforementioned issues, the present invention employs the following configuration.

[0010] The first aspect of the present invention is a washing liquid containing a solvent and a metal removal agent. The washing liquid contains two or more solvents, and the distance between the Hansen solubility parameter of the aforementioned washing liquid and the Hansen solubility parameter of dimethylacetamide (HSP distance) is 1.0 or less. The total content of organic matter selected from the group consisting of organic acid polymers, organic acid esters, and ketone bodies is 0.1 × 10⁻¹⁰ parts by mass relative to the total 100 parts by mass of the aforementioned solvent and the aforementioned metal removal agent. -9 10 or more by weight 5 ×10 -6 The weight is below 100 parts.

[0011] The second aspect of the present invention is a washing method, wherein the washing liquid involved in the first aspect is brought into contact with the object to be washed, thereby washing the object to be washed.

[0012] Invention Effects According to the present invention, a washing liquid with improved removability of organic impurities and dirt can be provided, as well as a washing method using the washing liquid.

[0013] The washing liquid and the washing method using it can be used to remove organic impurities and dirt from various objects to be washed. Detailed Implementation

[0014] (Method 1: Detergent) One embodiment of the detergent contains two or more solvents and a metal removal agent.

[0015] In this embodiment, the distance (HSP distance) between the Hansen solubility parameter of the aforementioned washing liquid and the Hansen solubility parameter of dimethylacetamide is less than 1.0.

[0016] Furthermore, in the washing liquid of this embodiment, the total content of organic matter selected from the group consisting of organic acid polymers, organic acid esters, and ketone bodies is 0.1 × 10⁻¹⁰ parts by mass relative to the total of 100 parts by mass of the aforementioned solvent and the aforementioned metal removal agent. -9 10 or more by weight 5 ×10 -6 The weight is below 100 parts.

[0017] Solvent The washing liquid in this embodiment contains two or more solvents.

[0018] The solvent contained in the washing liquid of this embodiment can be suitably selected from known organic solvents in such a way that the HSP distance is 1.0 or less as described above. Examples of such organic solvents include polar solvents such as ketone solvents, ester solvents, alcohol solvents, nitrile solvents, amide solvents, ether solvents, sulfoxide solvents, and sulfone solvents; and non-polar solvents such as hydrocarbon solvents.

[0019] As will be described later, there are also organic solvents whose structures contain multiple functional groups that impart characteristics to the solvents described above. In this case, they belong to any type of solvent containing the functional groups possessed by the organic solvent. For example, diethylene glycol monomethyl ether belongs to either alcohol-based solvents or ether-based solvents in the above classification.

[0020] ≪Ketone Solvents≫ Ketone solvents are organic solvents whose structure contains CC (=O)-C.

[0021] Specifically, examples of ketone solvents include 1-octanone, 2-octanone, 1-nonanone, 2-nonanone, acetone, 4-heptanone, 1-hexanone, 2-hexanone, diisobutyl ketone, phenylacetone, methyl ethyl ketone, methyl isobutyl ketone, ionone, diacetone alcohol, acetyl alcohol, acetoethyl ketone, methyl naphthyl ketone, methyl pentyl ketone (2-heptanone), etc.

[0022] In addition, cyclic ketone solvents can also be used as ketone solvents. Specific examples of such cyclic ketone solvents include cyclohexanone (CH), methylcyclohexanone, isophorone, propylene carbonate, ethylene carbonate, and dihydro-L-glucanone (Cyrene).

[0023] ≪Ester Solvents≫ Ester solvents are organic solvents whose structure contains CC (=O)-OC.

[0024] As ester solvents, examples include methyl acetate, butyl acetate, ethyl acetate, isopropyl acetate, amyl acetate, isoamyl acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monopropyl ether acetate, ethylene glycol monobutyl ether acetate, ethylene glycol monophenyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monopropyl ether acetate, diethylene glycol monophenyl ether acetate, diethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, 2-methoxybutyl acetate, 3-methoxybutyl acetate, 4-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate, 3-ethyl-3-methoxybutyl acetate, propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, 2-ethoxybutyl acetate, and 4-ethyl methoxybutyl acetate. Oxybutyl acetate, 4-propoxybutyl acetate, 2-methoxypentyl acetate, 3-methoxypentyl acetate, 4-methoxypentyl acetate, 2-methyl-3-methoxypentyl acetate, 3-methyl-3-methoxypentyl acetate, 3-methyl-4-methoxypentyl acetate, 4-methyl-4-methoxypentyl acetate, propylene glycol diacetate, methyl formate, ethyl formate, butyl formate, propyl formate, ethyl carbonate, propyl carbonate, butyl carbonate, methyl pyruvate, ethyl pyruvate, propyl pyruvate, butyl pyruvate, methyl acetoacetate, ethyl acetoacetate, methyl propionate, ethyl propionate, propyl propionate, isopropyl propionate, methyl 2-hydroxypropionate, ethyl 2-hydroxypropionate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, ethyl 3-ethoxypropionate, propyl 3-methoxypropionate, etc.

[0025] In addition, cyclic ester solvents (lactone solvents) can also be used as ester solvents. Specifically, examples of lactone solvents include γ-butyrolactone (GBL), ε-caprolactone, γ-valerolactone, and δ-valerolactone.

[0026] Alcohol-based solvents Alcohol solvents are organic solvents whose structure contains an alcoholic hydroxyl group.

[0027] "Alcoholic hydroxyl group" refers to a hydroxyl group bonded to a carbon atom of an aliphatic hydrocarbon group.

[0028] As alcohol solvents, examples include 2-propanol (isopropanol), 1-butanol (n-butanol), 1-hexanol, 1-heptanol, 1-octanol, 2-hexanol, 2-heptanol, 2-octanol, 3-hexanol, 3-heptanol, 3-octanol, 4-octanol, benzyl alcohol, ethylene glycol, diethylene glycol, propylene glycol (PG), dipropylene glycol, etc.

[0029] ≪Nitrile Solvents≫ Nitrile solvents are organic solvents whose structure contains nitrile groups.

[0030] Examples of nitrile solvents include acetonitrile, propionitrile, valerate, and butyronitrile.

[0031] ≪Amide solvents≫ Amide solvents are organic solvents whose structure contains amide groups.

[0032] Specifically, examples of amide solvents include chain-type amide solvents such as dimethylacetamide (DMAc), dimethylformamide, and tetramethylurea; and cyclic amide (lactam) solvents such as dimethylimidazolinone, N-methylpyrrolidone, 1-ethyl-2-pyrrolidone, and 1-butyl-2-pyrrolidone.

[0033] ≪Ether-based solvents≫ Ether solvents are organic solvents whose structure contains COC.

[0034] Specifically, examples of ether solvents include ethylene glycol monomethyl ether (EGME), ethylene glycol isopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monohexyl ether, propylene glycol monomethyl ether (PGME), propylene glycol monoethyl ether (PGEE), propylene glycol monopropyl ether, propylene glycol monobutyl ether, and diisopropylene glycol monomethyl ether.

[0035] ≪sulfoxide solvents≫ Sulfoxide solvents are organic solvents whose structure contains a sulfinyl group -S(=O)-.

[0036] As a sulfoxide solvent, dimethyl sulfoxide (DMSO) is a good example.

[0037] ≪Sulfone solvents≫ Sulfone solvents are organic solvents whose structure contains a sulfonyl group -S(=O)2-.

[0038] As a sulfone solvent, examples include sulfolane and cyclobutane.

[0039] Hydrocarbon solvents Hydrocarbon solvents are hydrocarbon solvents composed of halogenable hydrocarbons and without substituents other than halogen atoms. Examples of halogen atoms include fluorine, chlorine, bromine, and iodine atoms, with fluorine atoms being preferred.

[0040] As hydrocarbon solvents, examples include n-nonane, n-decane, n-undecane, n-dodecane, n-tridecane, n-tetradecane, n-pentadecanane, and n-hexadecane.

[0041] As the two or more solvents in the washing liquid of this embodiment, the preferred solvent is a mixture of two or more solvents selected from the group consisting of ketone solvents, ester solvents, alcohol solvents and ether solvents. More preferably, it is a mixture of two or more solvents selected from the group consisting of ketone solvents, ester solvents and ether solvents. Even more preferably, it is a mixture of two or more solvents selected from the group consisting of ester solvents and ether solvents.

[0042] It should be noted that, in this specification, the term "two or more solvents" simply refers to solvents containing two compounds, or solvents classified in the same way. For example, "two or more solvents" could also refer to a mixture of 1-octanone and cyclohexanone, both classified as ketone solvents.

[0043] Metal Remover Examples of metal removal agents contained in the washing liquid of this embodiment include metal chelating agents and organic acids.

[0044] Metal chelating agents Examples of metal chelating agents in this embodiment include aminocarboxylic acid chelating agents such as ethylenediaminetetraacetic acid, hypozoxytriacetic acid, and diethylenetriaminepentaacetic acid; phosphonic acid chelating agents such as 1-hydroxyethane-1,1-diphosphonic acid and hypozoxytris(methylenephosphonic acid); and compounds (A1) represented by the following general formula (a-1) (hereinafter also simply referred to as "compound (A1)"). Among these, compound (A1) is preferred as the metal chelating agent.

[0045] [Chemical Formula 1] [In the formula, Ra] 1 and Ra 2 Each is an alkyl group having 1 to 3 carbon atoms. Ra 3 and Ra 4 Each is independently an alkyl group having 1 to 3 hydrogen atoms or carbon atoms. Ya 1 And Ya 2 Each can be independently a single bond, -O-, -S-, or -N (Ra) 5 )-。 Ra 5 It is an alkyl group having 1 to 3 hydrogen atoms or carbon atoms. n is an integer from 0 to 3. In the aforementioned equation (a-1), Ra 1 ~Ra 5 Alkyl groups having 1 to 3 carbon atoms, such as methyl, ethyl, propyl, and isopropyl.

[0046] In the aforementioned equation (a-1), Ra 1 and Ra 2 Each of the ingredients is preferably methyl or ethyl, more preferably methyl.

[0047] Ra 3 and Ra 4 Each is preferably a hydrogen atom.

[0048] Ya 1 Preferably, it is a single bond or -O-, more preferably a single bond.

[0049] Ya 2 Preferably, it is a single bond or -O-, more preferably a single bond.

[0050] n is preferably 1 or 2, more preferably 1.

[0051] Of the above, the preferred compound (A1) is acetylacetone (AcAc) or acetone-based acetone, and more preferably acetylacetone (AcAc).

[0052] In the washing liquid of this embodiment, one type of metal chelating agent can be used alone, or two or more types can be used in combination.

[0053] Organic acids Examples of organic acids in this embodiment include carboxylic acids such as lactic acid (LA), citric acid, malic acid, formic acid, acetic acid, oxalic acid, 2-nitrophenylacetic acid, 2-ethylhexanoic acid, and dodecanoic acid; glycoacids such as ascorbic acid and glucuronic acid; sulfonic acids such as methanesulfonic acid, benzenesulfonic acid, and p-toluenesulfonic acid; phosphate esters such as bis(2-ethylhexyl)phosphate and phosphoric acid.

[0054] Of the above, the organic acid is preferably a carboxylic acid, more preferably a hydroxy acid, and even more preferably at least one selected from the group consisting of lactic acid, citric acid and malic acid, with lactic acid being particularly preferred.

[0055] In the washing liquid of this embodiment, one type of organic acid can be used alone, or two or more types can be used in combination.

[0056] The washing liquid in this embodiment preferably contains two or more metal removal agents.

[0057] The washing liquid of this embodiment preferably contains two or more metal removal agents selected from the group consisting of the metal chelating agent and organic acid described above, more preferably contains two or more metal removal agents selected from the group consisting of the compound (Al) described above and organic acid, and even more preferably contains two or more metal removal agents selected from the group consisting of the compound (Al) described above and carboxylic acid.

[0058] In the above-mentioned embodiments, the washing liquid preferably uses the metal chelating agent and organic acid mentioned above, more preferably uses the compound (A1) mentioned above and organic acid, and even more preferably uses the compound (A1) mentioned above and carboxylic acid.

[0059] <Any ingredient> The washing liquid of this embodiment may contain any components other than the solvent and metal remover described above, without compromising the effects of the present invention.

[0060] Examples of such components include, for example, pH adjusters and surfactants.

[0061] [Distance between Hansen solubility parameters (HSP distance)] The washing liquid of this embodiment contains two or more of the solvents and metal removal agents described above. The distance (HSP distance) between the Hansen solubility parameter of the washing liquid and the Hansen solubility parameter of dimethylacetamide (DMAc) is 1.0 or less, preferably 0.8 or less, and more preferably 0.5 or less.

[0062] If the HSP distance of the washing liquid in this embodiment is below the aforementioned upper limit, the removal effect of the washing liquid on organic impurities and dirt can be improved regardless of the material of the object being washed. From the perspective of improving the removal effect of the washing liquid on organic impurities and dirt, the lower the value of the HSP distance of the washing liquid in this embodiment, the better.

[0063] The “Hansen solubility parameter” referred to in this specification is theoretically calculated as a numerical constant and is a useful means of predicting the ability of a solvent material to dissolve a specific solute.

[0064] Regarding the Hansen solubility parameters, the following three Hansen solubility parameters (δ) can be derived experimentally and theoretically. d (Dispersion force term), δ p (Polarity term) and δ h (Hydrogen bond terms) combinations, thus serving as a standard for the overall strength and selectivity of the material. The unit for Hansen's solubility parameter is MPa. 0.5 Or (J / cc) 0.5 .

[0065] δ d Energy derived from intermolecular dispersion forces δ p Energy derived from intermolecular polar forces δ h Energy from intermolecular hydrogen bonding forces The "Hansen solubility parameter" can be calculated using, for example, software from "Molecular Modeling Pro", version 5.1.9 (ChemSW, Fairfield CA, www.chemsw.com) or Dynacomp Software's HansenSolubility.

[0066] It should be noted that, since the washing liquid in this embodiment is a mixture, the Hansen solubility parameter of the washing liquid in this embodiment can be obtained as described below.

[0067] For example, in the case of solvent S 1 (δ) ds1 δ ps1 δ hs1 Solvent S 2 (δ) ds2 δ ps2 δ hs2 Metal Remover B 1 (δ) dB1 δ pB1 δ hB1 ) and metal removal agent B 2 (δ) dB2 δ pB2 δ hB2 The washing liquid CS and solvent S formed 1 The amount of the solvent is a, and the amount of solvent S is S. 2 The dosage of the compound is b, metal removal agent B. 1 The amount of compound is c, and the metal removal agent B 2 When the amount of the mixture is d, the δ of the washing liquid CS dcs (Dispersion force term), δ pcs (Polarity term) and δ hcs The hydrogen bond term is calculated using the following formula. It should be noted that a + b + c + d = 100.

[0068] δ dcs =(δ ds1 ×a+δ ds2 ×b+δ dB1 ×c+δ dB2 ×d) / 100 δ pcs =(δ ps1 ×a+δ ps2 ×b+δ pB1 ×c+δ pB2 ×d) / 100 δ hcs =(δ hs1 ×a+δ hs2 ×b+δ hB1 ×c+δ hB2 ×d) / 100 The distance (HSP distance) between the Hansen solubility parameter of the washing liquid CS (the washing liquid of this embodiment) and the Hansen solubility parameter of dimethylacetamide (DMAc) is calculated using the following formula (1).

[0069] HSP distance = {4(δ)} dcs -δdDMAc ) 2 +(δ pcs -δ pDMAc ) 2 +(δ hcs -δ hDMAc ) 2} 0.5 ···(1) The dispersing power term (δ) of dimethylacetamide dDMAc Using a value of 16.8, the polarity term (δ) pDMAc Using a value of 11.5, the hydrogen bond term (δ) hDMAc The value is 9.4.

[0070] It should be noted that the organic matter (selected from the group consisting of organic acid polymers, organic acid esters and ketone bodies) contained in the washing liquid of this embodiment is present in trace amounts, and therefore has little impact on the aforementioned HSP distance variation.

[0071] In this embodiment, the HSP distance in the washing liquid can be achieved, for example, by using the dispersion term (δ) with dimethylacetamide. dDMAc ), polarity term (δ) pDMAc ) and hydrogen bond term (δ hDMAc The value can be controlled by using solvents or metal removers with values ​​close to those of the components, or by selecting a combination of components.

[0072] [Select the total content of organic matter in the group composed of organic acid polymers, organic acid esters, and ketone bodies] In the washing liquid of this embodiment, the total content of organic matter selected from the group consisting of organic acid polymers, organic acid esters, and ketone bodies is 0.1 × 10⁻⁶ parts by mass relative to the total 100 parts by mass of the solvent and the metal removal agent. -9 10 or more by weight 5 ×10 -6 Less than, preferably 5 × 10 parts by weight -9 5 x 10 parts by weight or more -6 Less than, more preferably 10 × 10 parts by weight -9 2.5 × 10 parts by weight or more -6 Less than, more preferably 50 × 10 parts by weight -9 1×10 parts by weight or more -6 The weight is below 100 parts.

[0073] In this embodiment, when the total content of the aforementioned organic matter in the washing liquid is within the aforementioned range, the removal effect of organic impurities and dirt in the washing liquid can be further improved regardless of the material of the object being washed.

[0074] The "organic matter" contained in the detergent of this embodiment refers to organic compounds selected from the group consisting of organic acid polymers, organic acid esters and ketone bodies.

[0075] Examples of organic acid polymers include lactic acid polymers and lactic anhydride. Examples of organic acid esters include ethyl lactate and 1-methoxy-2-propyl acetate. Examples of ketone bodies include 1-methoxy-2-propanone.

[0076] The total mass of the organic matter in the washing liquid can be determined by appropriately selecting a known analytical method.

[0077] The total content of the organic matter in the detergent can be adjusted by controlling the amount of the organic matter contained in the solvent or metal remover used in the solution; or by adding the organic matter separately from the solvent, metal remover and any other ingredients after mixing, or by removing excess organic matter.

[0078] As the washing liquid of this embodiment, the following composition (X) is preferably provided. Composition (X) is a mixture containing two or more solvents selected from the group consisting of ketone solvents, ester solvents, alcohol solvents, and ether solvents, the aforementioned metal chelating agent, and the aforementioned organic acid. The HSP distance of composition (X) is 1.0 or less, and the total content of organic matter selected from the group consisting of organic acid polymers, organic acid esters, and ketone bodies is 0.1 × 10⁻¹¹ parts by mass relative to the total of 100 parts by mass of the aforementioned mixed solvent, the aforementioned metal chelating agent, and the aforementioned organic acid. -9 10 or more by weight 5 ×10 -6 The weight is below 100 parts.

[0079] The distance (HSP distance) between the Hansen solubility parameter of the aforementioned composition (X) and the Hansen solubility parameter of DMAc is 1.0 or less, preferably 0.8 or less, more preferably 0.5 or less, even more preferably 0.4 or less, particularly preferably 0.3 or less, and the lower the value, the more preferred.

[0080] The mixed solvent in the aforementioned composition (X) is more preferably a mixed solvent selected from one or more solvents of the group consisting of ketone solvents and ester solvents (hereinafter also referred to as "solvent S1") and one or more solvents selected from the group consisting of alcohol solvents and ether solvents (hereinafter also referred to as "solvent S2"), and is even more preferably a mixed solvent of ester solvents and ether solvents, and is particularly preferably a mixed solvent of lactone solvents and ether solvents.

[0081] For example, when the two or more solvents in the aforementioned composition (X) are a mixture of solvent S1 and solvent S2, the mixing ratio of solvent S1 and solvent S2 (solvent S1:solvent S2) by mass is preferably 20:80 to 80:20, more preferably 30:70 to 70:30, and even more preferably 40:60 to 60:40.

[0082] Preferred combinations of two or more solvents in the aforementioned composition (X) include: one or more solvents selected from the group consisting of γ-butyrolactone, ε-caprolactone and γ-valerolactone; a mixed solvent with one or more solvents selected from the group consisting of EGME, PGME and PGEE; and a mixed solvent of dihydro-L-glucanone (Cyrene) and PG.

[0083] Among them, the preferred combination of two or more solvents is preferably a mixture of one or more solvents selected from the group consisting of γ-butyrolactone, ε-caprolactone and γ-valerolactone and one or more solvents selected from the group consisting of EGME, PGME and PGEE, and more preferably a mixture of γ-butyrolactone and PGME.

[0084] The metal chelating agent in the aforementioned composition (X) is preferably compound (A1), and more preferably acetylacetone (AcAc).

[0085] The organic acid in the aforementioned composition (X) is preferably a carboxylic acid, more preferably a hydroxy acid, and even more preferably lactic acid.

[0086] The organic compound is selected from the group consisting of organic acid polymers, organic acid esters and ketone bodies, preferably at least one selected from the group consisting of lactic acid polymers, lactic anhydride, ethyl lactate, 1-methoxy-2-propyl acetate and 1-methoxy-2-propanone, more preferably at least one selected from the group consisting of lactic acid polymers, ethyl lactate, 1-methoxy-2-propyl acetate and 1-methoxy-2-propanone.

[0087] In the aforementioned composition (X), the total content of organic matter selected from the group consisting of organic acid polymers, organic acid esters, and ketone bodies is 0.1 × 10⁻¹⁰ parts by mass relative to the total of 100 parts by mass of the aforementioned mixed solvent, the aforementioned metal chelating agent, and the aforementioned organic acid. -9 10 or more by weight 5 ×10 -6 Less than, preferably 5 × 10 parts by weight -9 5 x 10 parts by weight or more -6 Less than, more preferably 10 × 10 parts by weight -9 2.5 × 10 parts by weight or more -6 Less than, more preferably 50 × 10 parts by weight -91×10 parts by weight or more -6 The weight is below 100 parts.

[0088] In the aforementioned composition (X), the contents of the mixed solvent, the metal chelating agent, and the organic acid are suitably selected such that the HSP distance is 1.0 or less.

[0089] The content of the mixed solvent in the aforementioned composition (X) is preferably 90 to 99.5% by mass relative to the total amount of composition (X), more preferably 95 to 99% by mass.

[0090] The content of the metal chelating agent in the aforementioned composition (X) is preferably 0.1 to 9% by mass relative to the total amount of composition (X), more preferably 0.5 to 9% by mass, and even more preferably 0.5 to 5% by mass.

[0091] The proportion of compound (A1) in the metal chelating agent is preferably 50% by mass or more, more preferably 75% by mass or more, and may also be 100% by mass relative to the total mass of the metal chelating agent.

[0092] The content of organic acid in the aforementioned composition (X) is preferably 0.1 to 9% by mass relative to 100% by mass of the total amount of composition (X), more preferably 0.5 to 9% by mass, and even more preferably 0.5 to 5% by mass.

[0093] The proportion of carboxylic acid in the organic acid is preferably 50% by mass or more, more preferably 75% by mass or more, or 100% by mass, relative to the total mass of the organic acid.

[0094] In addition to the mixed solvent, metal chelating agent and organic acid, the aforementioned composition (X) may further contain any of the above-mentioned components as needed.

[0095] The washing solution in this embodiment is a washing solution that can be used to wash the membrane.

[0096] There are no particular limitations on the shape or form of the membrane. Examples include flat membranes, hollow fiber membranes, tubular membranes, spiral membranes, and thin films.

[0097] Furthermore, there are no particular limitations on the material of the membrane. For example, polyolefins (polyethylene, polypropylene, etc.), polysulfone, polyacrylonitrile, polyamide, polyimide, polyvinyl alcohol, cellulose acetate, fluoropolymers, ceramics, etc. can be mentioned.

[0098] Furthermore, the washing solution of this embodiment can also be used to remove organic impurities and dirt from various types of objects to be washed. Examples of various objects to be washed include pipes, containers, and appliances used in a production line. For instance, the washing solution of this embodiment can be used to wash objects selected from the group consisting of metal pipes, resin pipes, glass pipes, metal fittings, resin fittings, glass fittings, filters, pharmaceutical containers, measuring cells, and chromatographic columns.

[0099] The washing liquid of this embodiment described above contains two or more solvents and metal removal agents. Furthermore, the distance between the Hansen solubility parameter of the washing liquid and the Hansen solubility parameter of dimethylacetamide (DMAc) (HSP distance) is 1.0 or less, and the total content of organic matter selected from the group consisting of organic acid polymers, organic acid esters, and ketone bodies is 0.1 × 10⁻¹⁰ parts by mass relative to the total of 100 parts by mass of the aforementioned solvents and metal removal agents. -9 10 or more by weight 5 ×10 -6 The weight is below 100 parts.

[0100] Regarding the washing liquid, since the overall Hansen solubility parameter of the washing liquid has been adjusted to be close to DMAc, the removal of polymer residues from polymer materials is good.

[0101] Regarding the aforementioned washing liquid, although the reason is unclear, it achieves good washing and removal effects on both polar and non-polar objects by adjusting the overall Hansen solubility parameter of the washing liquid to be close to DMAc and by containing a metal removal agent.

[0102] Furthermore, the washing solution intentionally contains a specific amount of organic matter. This further enhances the removal effect of organic impurities and dirt on various objects being washed.

[0103] In addition, since the washing liquid of this embodiment contains a metal removal agent, it also has good removal properties for metal impurities and dirt.

[0104] (Second method: washing method) One embodiment of the washing method is the following method, wherein the washing liquid is brought into contact with the object to be washed, thereby washing the object.

[0105] Regarding the objects to be washed in the washing method of this embodiment, examples include membranes; various pipes in the production line, containers used, and appliances. For example, the objects to be washed can be flat membranes, hollow fiber membranes, tubular membranes, spiral membranes, thin films, etc. Alternatively, the objects to be washed can be items selected from the group consisting of metal pipes, resin pipes, glass pipes, metal connectors, resin connectors, glass connectors, filters, pharmaceutical containers, measuring cells, and chromatographic columns.

[0106] More specifically, examples of washing operations that involve bringing the washing liquid into contact with the object to be washed include immersing the object in the washing liquid and spraying the washing liquid onto the object.

[0107] The washing process can be performed once or multiple times.

[0108] In addition, the washing solution can be heated during the washing process, or the washing process can be carried out at room temperature (e.g., 23°C).

[0109] The washing method of this embodiment may also include a drying step of drying the washed object after washing by the above washing operation. The drying step can be performed using known methods such as air drying at room temperature, heating the washed object in a constant temperature bath, or vacuum drying.

[0110] The washing method of this embodiment described above, due to the use of the aforementioned washing liquid, exhibits excellent removal performance for organic impurities and dirt on various objects to be washed.

[0111] Another embodiment of the washing method is the following method, wherein, before or after the step of washing the object by contacting the washing liquid with the object (hereinafter also referred to as "washing step A"), there is a step of washing the object by contacting a second washing liquid different from the washing liquid with the object (hereinafter also referred to as "washing step B").

[0112] In the washing methods of the other embodiments described above, (i) It may include the following steps: a step of contacting a second washing liquid, different from the washing liquid described above (referred to as the first washing liquid), with the object to be washed to wash the object; and a step of contacting the object to be washed with the second washing liquid with the first washing liquid to wash the object. (ii) It may include the following steps: a step of contacting the aforementioned washing liquid (first washing liquid) with the object to be washed to wash the object; and a step of contacting the object to be washed with a second washing liquid, different from the first washing liquid, with the object to be washed after being washed with the first washing liquid to wash the object. (iii) It may include the following steps: a step of washing the object by contacting a second washing liquid (different from the first washing liquid) with the object to be washed; a step of washing the object after it has been washed with the second washing liquid by contacting the first washing liquid with the first washing liquid; and a step of further washing the object after it has been washed with the first washing liquid by contacting a third washing liquid (different from the first washing liquid) with the object to be washed.

[0113] In (iii), the second washing solution and the third washing solution can be the same as each other or different.

[0114] Washing process B As a method for washing the object by bringing a second washing liquid, different from the washing liquid described above, into contact with the object to be washed in washing step B, the same method as the method in washing step A described above (such as immersing the object to be washed in the washing liquid or spraying the washing liquid onto the object to be washed).

[0115] Washing step B can be performed only once before or after washing step A, or it can be performed multiple times.

[0116] • Second wash solution, third wash solution As a washing solution different from the washing solutions described above (the second washing solution and the third washing solution), examples include washing solutions that contain solvents but do not contain metal removal agents. Typically, washing solutions (the second washing solution and the third washing solution) can be described as washing solutions formed solely of solvents.

[0117] Examples of solvents used in the washing solutions (second washing solution and third washing solution) include polar solvents such as ketone solvents, ester solvents, alcohol solvents, nitrile solvents, amide solvents, ether solvents, sulfoxide solvents, and sulfone solvents; and non-polar solvents such as hydrocarbon solvents. Specifically, examples of solvents similar to those used in the washing solutions mentioned above can be cited.

[0118] Of the above, the washing liquid (second washing liquid, third washing liquid) preferably contains an alcohol solvent, more preferably an alcohol solvent with 1 to 5 carbon atoms, and even more preferably contains 2-propanol (isopropanol).

[0119] As another embodiment of the washing method, a preferred method is one that includes a washing step A and a step of washing the object by contacting an alcohol solvent (preferably 2-propanol) with the object before or after the washing step A.

[0120] Other embodiments of the washing method may also include a drying step of drying the object to be washed after washing step A or washing step B.

[0121] As a drying process, the following methods can be used: air drying at room temperature; heating the washed object in a constant temperature bath; vacuum drying, and other known methods.

[0122] According to other embodiments of the washing method described above, since it is a washing method that includes a washing step B in addition to the washing step A described above, it can further improve the removal effect of organic impurities and dirt adhering to the object to be washed compared with a washing method that only has the washing step A described above.

[0123] Example The present invention will be described in more detail below using examples, but the present invention is not limited to these examples.

[0124] <Preparation of Washing Solution> The washing solutions for each example were prepared by mixing the components according to the composition ratios shown in Table 1.

[0125] [Table 1] The abbreviations in the table represent the following compounds. The values ​​in parentheses in the table are the amounts (parts by mass).

[0126] GBL: γ-Butyrolactone PGME: Propylene Glycol Monomethyl Ether PGMEA: Propylene glycol monomethyl ether acetate AcAc: Acetylacetone LA: lactic acid BA: n-butylacetic acid DMSO: Dimethyl sulfoxide (See Example 1 for reference) The washing solution of Reference Example 1 was prepared by adding 1 part by mass of lactic acid (LA) to 49 parts by mass of γ-butyrolactone (GBL), 49 parts by mass of propylene glycol monomethyl ether (PGME), and 1 part by mass of acetylacetone (AcAc).

[0127] (Example 1) Instead of lactic acid (LA), lactic acid containing 80% lactic acid polymer was used, and the washing solution of Example 1 was prepared in the same manner as in Reference Example 1.

[0128] The identification and quantification of lactic acid polymers were performed using gel permeation chromatography (GPC). The content of lactic acid polymers relative to 100 parts by mass of the total solvent and metal removal agent was 2 × 10⁻⁶. -9 Weight of portions.

[0129] (Example 2) Ethyl lactate was added to the washing solution of Reference Example 1 to prepare the washing solution of Example 2. In this case, the content of ethyl lactate was 1 × 10⁻¹⁰ parts by mass relative to the total 100 parts by mass of the solvent and the metal removal agent. -6 Weight of portions.

[0130] (Example 3) Ethyl lactate was added to the washing solution of Reference Example 1 to prepare the washing solution of Example 3. In this case, the content of ethyl lactate was set to 10 parts by mass relative to the total 100 parts by mass of the solvent and the metal removal agent. 3 ×10 -6 Weight of portions.

[0131] (Example 4) 1-Methoxy-2-propyl acetate was added to the washing solution of Reference Example 1 to prepare the washing solution of Example 4. In this case, the content of 1-methoxy-2-propyl acetate was 1 × 10⁻¹⁰ parts by mass relative to the total 100 parts by mass of the solvent and the metal removal agent. -6 Weight of portions.

[0132] (Example 5) 1-Methoxy-2-propyl acetate was added to the washing solution of Reference Example 1 to prepare the washing solution of Example 5. In this case, the content of 1-methoxy-2-propyl acetate was set to 10 parts by mass relative to the total 100 parts by mass of the solvent and the metal removal agent. 3 ×10 -6 Weight of portions.

[0133] (Example 6) 1-Methoxy-2-propanone was added to the washing solution of Reference Example 1 to prepare the washing solution of Example 6. In this case, the content of 1-methoxy-2-propanone was 1 × 10⁻¹⁰ parts by mass relative to the total 100 parts by mass of the solvent and the metal removal agent. -6 Weight of portions.

[0134] (Example 7) 1-Methoxy-2-propanone was added to the washing solution of Reference Example 1 to prepare the washing solution of Example 7. In this case, the content of 1-methoxy-2-propanone was set to 10 parts by mass relative to the total 100 parts by mass of the solvent and the metal removal agent. 3 ×10 -6 Weight of portions.

[0135] (Comparative Example 1) As the washing solution for Comparative Example 1, n-butylacetic acid was used.

[0136] (Comparative Example 2) As the washing solution for Comparative Example 2, OK73 diluent was used. The composition of OK73 diluent is a mixed solvent of PGMEA / PGME = 30 / 70 (mass ratio).

[0137] (Comparative Example 3) As the washing solution for Comparative Example 3, a mixed solvent of PGMEA / DMSO = 55 / 45 (mass ratio) was used.

[0138] [Calculation of HSP distance] The Hansen solubility parameters of each component of the detergent solution were calculated using "Molecular Modeling Pro" software, version 5.1.9 (ChemSW, Fairfield CA, www.chemsw.com). The Hansen solubility parameters of each component are shown below.

[0139] The dispersion term of GBL (δ) dGBL Using a value of 18, the polarity term (δ) pGBL Using a value of 16.6, the hydrogen bond term (δ) hGBL The value is 7.4.

[0140] The dispersion term of PGME (δ) dPGME Using a value of 15.6, the polarity term (δ) pPGME Using a value of 6.3, the hydrogen bond term (δ) hPGME The value is 11.6.

[0141] The dispersion term of AcAc (δ) dAcAc Using a value of 16.1, the polarity term (δ) pAcAc Using a value of 10, the hydrogen bond term (δ) hAcAc The value of 6.2 is used.

[0142] The dispersion term of LA (δ) dLA Using a value of 17, the polarity term (δ) pLA Using a value of 8.3, the hydrogen bond term (δ) hLA The value is 28.4.

[0143] The dispersion term (δ) of PGMEA dPGMEA Using a value of 15.6, the polarity term (δ) pPGMEA Using a value of 6.3, the hydrogen bond term (δ) hPGMEA The value is 7.7.

[0144] The dispersion term of BA (δ) dBA Using a value of 15.6, the polarity term (δ) pBA Using a value of 3.7, the hydrogen bond term (δ) hBA The value is 6.3.

[0145] The dispersion term of DMSO (δ) dDMSO Using a value of 18.4, the polarity term (δ) pDMSO Using a value of 16.4, the hydrogen bond term (δ) hDMSO The value is 10.2.

[0146] Regarding the dispersing power term (δ) of the washing liquid in Reference Example 1 and Examples 1-7 dt ), polarity term (δ) pt ) and hydrogen bond term (δ ht The following is how it is determined.

[0147] δ dt =(δ dGBL ×49+δ dPGME ×49+δ dAcAc ×1+δ dLA ×1) / 100 δ pt =(δ pGBL ×49+δ pPGME ×49+δ dAcAc ×1+δ dLA ×1) / 100 δ ht =(δ hGBL ×49+δ hPGME ×49+δ dAcAc ×1+δ dLA ×1) / 100 Regarding the dispersing force term (δ) of the detergent in Comparative Example 1 dt ), polarity term (δ) pt ) and hydrogen bond term (δ ht The following is how it is determined.

[0148] δ dt =(δ dBA (×100) / 100 δ pt =(δ pBA (×100) / 100 δ ht =(δ hBA(×100) / 100 Regarding the dispersing force term (δ) of the washing liquid in Comparative Example 2 dt ), polarity term (δ) pt ) and hydrogen bond term (δ ht The following is how it is determined.

[0149] δ dt =(δ dPGMEA ×30+δ dPGME (×70) / 100 δ pt =(δ pPGMEA ×30+δ pPGME (×70) / 100 δ ht =(δ hPGMEA ×30+δ hPGME (×70) / 100 Regarding the dispersing power term (δ) of the detergent in Comparative Example 3 dt ), polarity term (δ) pt ) and hydrogen bond term (δ ht The following is how it is determined.

[0150] δ dt =(δ dPGMEA ×55+δ dDMSO (×45) / 100 δ pt =(δ pPGMEA ×55+δ pDMSO (×45) / 100 δ ht =(δ hPGMEA ×55+δ hDMSO (×45) / 100 Hansen solubility parameters (MPa) of the washing solutions in Reference Example 1 and Examples 1-7 0.5 Hansen solubility parameters (MPa) of dimethylacetamide and dimethylacetamide 0.5 The distance between (HSP distance) is calculated using the following formula (1t).

[0151] The dispersing power term (δ) of dimethylacetamide dDMAc Using a value of 16.8, the polarity term (δ) pDMAc Using a value of 11.5, the hydrogen bond term (δ) hDMAc The value is 9.4.

[0152] HSP distance = {4(δ)} dt -δ dDMAc ) 2 +(δ pt -δ pDMAc ) 2 +(δ ht-δ hDMAc ) 2} 0.5 ···(1t) The distance between the Hansen solubility parameters of the washing solutions in Comparative Examples 1-3 and the Hansen solubility parameters of dimethylacetamide (HSP distance) was calculated in the same manner as in Reference Example 1 and Examples 1-7.

[0153] <Washing Evaluation (1)> As the objects of washing, polyethylene-based porous membranes (PE membranes) and polyimide-based porous membranes (PI membranes) were washed using washing solutions of various types, as shown below, thereby measuring the non-volatile residue (NVR). Then, based on the measurement results, the removal performance of organic impurities was evaluated.

[0154] As a PE film, 1000cm 2 Porous polyethylene film.

[0155] As a PI membrane, 1000cm 2 Porous polyimide membrane.

[0156] (Refer to Example 1-1, Examples 1-1 to 1-7, Comparative Examples 1-1 to 1-3) Add 100 mL of the washing solution from Reference Example 1, Examples 1-7, and Comparative Examples 1-3 to the container respectively.

[0157] Add 1000 cm to 100 mL of the washing solution in each example. 2 The porous polyethylene membrane was impregnated for 1 day. Separately, 1000 cm³ of the washing solution was added to 100 mL of each sample. 2 The porous polyimide membrane was impregnated for 1 day.

[0158] Then, the washing liquid was removed from each container, and isopropanol was added to each container to rinse the porous polyethylene membrane and the porous polyimide membrane.

[0159] After rinsing, the porous polyethylene membrane and the porous polyimide membrane are vacuum dried overnight.

[0160] Each dried membrane was immersed in isopropanol, then removed. The residual isopropanol was transferred to a platinum dish and allowed to evaporate. The weight of the platinum dish was then measured. The mass of the nonvolatile residue (NVR) was determined based on the weight difference between the NVR and the initial weight of the platinum dish.

[0161] The ability to remove organic impurities is evaluated by dividing the mass of the NVR of the membrane after immersion washing with washing liquid by the mass of the NVR of the unwashed membrane (after rinsing with isopropanol) (hereinafter referred to as "residue removal rate").

[0162] The residue removal rate when using PE membrane as the washing target is denoted as "PE NVR", and the residue removal rate when using PI membrane as the washing target is denoted as "PI NVR", as shown in Table 2.

[0163] The lower the residue removal rate, the better the washing liquid removes organic impurities and dirt from each membrane.

[0164] [Table 2] The results shown in Table 2 confirm that, when using the washing solutions of Examples 1-7, the residue removal rate is lower when the PI membrane is the object of washing compared to when using the washing solutions of Comparative Examples 1-3. Therefore, it can be confirmed that the washing solution of the present invention can improve the removal of organic impurities and dirt from porous polyimide membranes.

[0165] It was confirmed that although the washing liquids of Examples 1 to 7 were obtained by further adding a specific amount of organic matter to the washing liquid of Reference Example 1, they had the same good washing performance as the washing liquid of Reference Example 1.

[0166] <Washing Evaluation (2)> For the chemical supply line (piping through which BARC chemical solution flows) that is the object to be cleaned, cleaning solutions of various examples were used, and cleaning methods were employed as shown below. The removal efficiency of organic impurities was evaluated using the number of defects on the wafer surface as an indicator. The results are shown in Table 3.

[0167] (Refer to Example 2-1) Connect the antireflective coating (BARC) solution bottle (Novolac resin, solvent PGEE; ARC-212, BrewerScience) to the solution supply line of the resist coating and developing apparatus (Lithius ProZ, Tokyo Electron Limited) and allow the solution to flow through for a certain period of time.

[0168] After a certain period of liquid flow, the solution bottle is replaced with OK73 diluent. The OK73 diluent is then immersed in the piping for 1 day, followed by liquid flow of 3L of OK73 diluent.

[0169] The OK73 diluent, after being flushed, was spin-coated onto a 12-inch wafer and baked at 80°C for 60 seconds. Then, the number of defects larger than 17 nm was measured using a wafer surface defect analyzer (Surf Scan SP5 XP, KLA Tencor), yielding 33,099 defects. It should be noted that the number of defects in the PGME diluent before piping connection (based on the cleanliness of the PGME itself) was 550.

[0170] Then, the washing solution was switched to that of Reference Example 1 and passed through the solution. The wafer was immersed in the piping for one day, followed by passing through 1L of the washing solution from Reference Example 1. Then, the solution was switched to OK73 diluent, and 1L of OK73 diluent was passed through the solution. The wafer was then spin-coated onto a 12-inch wafer and baked at 80°C for 60 seconds. The number of defects larger than 17nm was then measured using the aforementioned wafer surface defect device. The result showed that the number of defects had been reduced to 876.

[0171] (Example 2-1) The washing solution of Reference Example 1 was replaced with the washing solution of Example 1 and the solution was circulated. After soaking in the piping of the aforementioned drug supply line for 1 day, 1L of the washing solution of Example 1 was circulated, and then OK73 diluent was switched and 1L was circulated.

[0172] The OK73 diluent after liquid permeation was spin-coated onto a 12-inch wafer and baked at 80°C for 60 seconds. Then, the number of defects larger than 17 nm was measured using the aforementioned wafer surface defect device, and the result showed that the number of defects had been reduced to 912.

[0173] (Example 2-2) The washing solution of Reference Example 1 was replaced with the washing solution of Example 2 and the solution was circulated. After soaking in the piping of the aforementioned drug supply line for 1 day, 1L of the washing solution of Example 2 was circulated, and then 1L of OK73 diluent was switched and circulated.

[0174] The OK73 diluent after liquid permeation was spin-coated onto a 12-inch wafer and baked at 80°C for 60 seconds. Then, the number of defects larger than 17 nm was measured using the aforementioned wafer surface defect device, and the result showed that the number of defects had been reduced to 866.

[0175] (Examples 2-3) The washing solution of Reference Example 1 was replaced with the washing solution of Example 3 and the solution was circulated. After soaking in the piping of the aforementioned drug supply line for 1 day, 1L of the washing solution of Example 3 was circulated, and then OK73 diluent was switched and 1L was circulated.

[0176] The OK73 diluent after liquid permeation was spin-coated onto a 12-inch wafer and baked at 80°C for 60 seconds. Then, the number of defects larger than 17 nm was measured using the aforementioned wafer surface defect device, and the result showed that the number of defects had been reduced to 934.

[0177] (Examples 2-4) The washing solution of Reference Example 1 was replaced with the washing solution of Example 4 and the solution was circulated. After soaking in the piping of the aforementioned drug supply line for 1 day, 1L of the washing solution of Example 4 was circulated, and then 1L of OK73 diluent was switched and circulated.

[0178] The OK73 diluent after liquid permeation was spin-coated onto a 12-inch wafer and baked at 80°C for 60 seconds. Then, the number of defects larger than 17 nm was measured using the aforementioned wafer surface defect device, and the result showed that the number of defects had been reduced to 884.

[0179] (Examples 2-5) The washing solution of Reference Example 1 was replaced with the washing solution of Example 5 and the solution was circulated. After soaking in the piping of the aforementioned drug supply line for 1 day, 1L of the washing solution of Example 5 was circulated, and then OK73 diluent was switched and 1L was circulated.

[0180] The OK73 diluent after liquid permeation was spin-coated onto a 12-inch wafer and baked at 80°C for 60 seconds. Then, the number of defects larger than 17 nm was measured using the aforementioned wafer surface defect device, and the result showed that the number of defects had been reduced to 871.

[0181] (Examples 2-6) The washing solution of Reference Example 1 was replaced with the washing solution of Example 6 and the solution was circulated. After soaking in the piping of the aforementioned drug supply line for 1 day, 1L of the washing solution of Example 6 was circulated, and then OK73 diluent was switched and 1L was circulated.

[0182] The OK73 diluent after liquid permeation was spin-coated onto a 12-inch wafer and baked at 80°C for 60 seconds. Then, the number of defects larger than 17 nm was measured using the aforementioned wafer surface defect device, and the result showed that the number of defects had been reduced to 962.

[0183] (Examples 2-7) The washing solution of Reference Example 1 was replaced with the washing solution of Example 7 and the solution was circulated. After soaking in the piping of the aforementioned drug supply line for 1 day, 1L of the washing solution of Example 7 was circulated, and then OK73 diluent was switched and 1L was circulated.

[0184] The OK73 diluent after liquid permeation was spin-coated onto a 12-inch wafer and baked at 80°C for 60 seconds. Then, the number of defects larger than 17 nm was measured using the aforementioned wafer surface defect device, and the result showed that the number of defects had been reduced to 837.

[0185] (Comparative Example 2-1) The washing solution of Reference Example 1 was replaced with the washing solution of Comparative Example 1 and the solution was circulated. After soaking in the piping of the aforementioned drug supply line for 1 day, 1L of the washing solution of Comparative Example 1 was circulated, and then OK73 diluent was switched and 1L was circulated.

[0186] The OK73 diluent after liquid permeation was spin-coated onto a 12-inch wafer and baked at 80°C for 60 seconds. Then, the number of defects larger than 17 nm was measured using the aforementioned wafer surface defect device, and the result showed that the number of defects had been reduced to 35,621.

[0187] (Comparative Example 2-2) The washing solution of Reference Example 1 was replaced with the washing solution of Comparative Example 2 and the solution was circulated. After soaking in the piping of the aforementioned drug supply line for 1 day, 1L of the washing solution of Comparative Example 2 was circulated. Then, OK73 diluent, which is different from the washing solution of Comparative Example 2, was switched and 1L of solution was circulated.

[0188] The OK73 diluent after liquid permeation was spin-coated onto a 12-inch wafer and baked at 80°C for 60 seconds. Then, the number of defects larger than 17 nm was measured using the aforementioned wafer surface defect device, and the result showed that the number of defects had been reduced to 32,804.

[0189] (Comparative Examples 2-3) The washing solution of Reference Example 1 was replaced with the washing solution of Comparative Example 3 and the solution was circulated. After soaking in the piping of the aforementioned drug supply line for 1 day, 1L of the washing solution of Comparative Example 3 was circulated, and then 1L of OK73 diluent was switched and circulated.

[0190] The OK73 diluent after liquid permeation was spin-coated onto a 12-inch wafer and baked at 80°C for 60 seconds. Then, the number of defects larger than 17 nm was measured using the aforementioned wafer surface defect device, and the result showed that the number of defects had been reduced to 34,152.

[0191] [Table 3] The results shown in Table 3 confirm that when the cleaning solutions of Examples 1 to 7 are used, the number of defects on the wafer surface is significantly reduced compared to when the cleaning solutions of Comparative Examples 1 to 3 are used. Therefore, the cleaning solution of the present invention can improve the removal of organic impurities and dirt in the piping after the BARC solution is passed through.

[0192] In the <Washing Evaluation (2)>, it was also confirmed that although the washing liquids of Examples 1 to 7 were obtained by further adding a specific amount of organic matter to the composition of the washing liquid of Reference Example 1, they had the same good washing performance as the washing liquid of Reference Example 1.

[0193] <Washing Evaluation (3)> For the chemical supply line (pipeline through which SOG (spin-on-glass) chemical solution is passed) that is the object to be cleaned, cleaning methods were employed using various cleaning solutions as shown below. The removal efficiency of organic impurities was evaluated using the number of defects on the wafer surface as an indicator. The results are shown in Table 4.

[0194] (Refer to Example 3-1) Connect the SOG solution (HM-825, Shin-Etsu Chemical Co., Ltd.) bottle to the solution supply line of the resist coating and developing apparatus (Lithius i+, Tokyo Electron Limited) and allow the solution to flow through for a certain period of time.

[0195] After a certain period of liquid flow, the solution bottle is replaced with OK73 diluent. The OK73 diluent is then immersed in the piping for 1 day, followed by liquid flow of 3L of OK73 diluent.

[0196] The OK73 diluent, after being flushed, was spin-coated onto a 12-inch wafer and baked at 80°C for 60 seconds. Then, the number of defects larger than 19 nm was measured using a wafer surface defect analyzer (Surf Scan SP5 XP, KLA Tencor), yielding 5255 defects. It should be noted that the number of defects in the PGME diluent before piping connection (based on the cleanliness of the PGME itself) was 550.

[0197] Then, the washing solution was switched to that of Reference Example 1 and passed through the solution. The wafer was immersed in the piping for one day, followed by passing through 1L of the washing solution from Reference Example 1. Then, the solution was switched to OK73 diluent, and 1L of OK73 diluent was passed through the solution. The wafer was then spin-coated onto a 12-inch wafer and baked at 80°C for 60 seconds. The number of defects larger than 19nm was then measured using the aforementioned wafer surface defect device. As a result, the number of defects was reduced to 180.

[0198] (Example 3-1) The washing solution of Reference Example 1 was replaced with the washing solution of Example 1 and the solution was circulated. After soaking in the piping of the aforementioned drug supply line for 1 day, 1L of the washing solution of Example 1 was circulated, and then OK73 diluent was switched and 1L was circulated.

[0199] The OK73 diluent after liquid permeation was spin-coated onto a 12-inch wafer and baked at 80°C for 60 seconds. Then, the number of defects larger than 19 nm was measured using the aforementioned wafer surface defect device, and the result showed that the number of defects had been reduced to 165.

[0200] (Example 3-2) The washing solution of Reference Example 1 was replaced with the washing solution of Example 2 and the solution was circulated. After soaking in the piping of the aforementioned drug supply line for 1 day, 1L of the washing solution of Example 2 was circulated, and then 1L of OK73 diluent was switched and circulated.

[0201] The OK73 diluent after liquid permeation was spin-coated onto a 12-inch wafer and baked at 80°C for 60 seconds. Then, the number of defects larger than 19 nm was measured using the aforementioned wafer surface defect device, and the result showed that the number of defects had been reduced to 172.

[0202] (Example 3-3) The washing solution of Reference Example 1 was replaced with the washing solution of Example 3 and the solution was circulated. After soaking in the piping of the aforementioned drug supply line for 1 day, 1L of the washing solution of Example 3 was circulated, and then OK73 diluent was switched and 1L was circulated.

[0203] The OK73 diluent after liquid permeation was spin-coated onto a 12-inch wafer and baked at 80°C for 60 seconds. Then, the number of defects larger than 19 nm was measured using the aforementioned wafer surface defect device, and the result showed that the number of defects had been reduced to 152.

[0204] (Examples 3-4) The washing solution of Reference Example 1 was replaced with the washing solution of Example 4 and the solution was circulated. After soaking in the piping of the aforementioned drug supply line for 1 day, 1L of the washing solution of Example 4 was circulated, and then 1L of OK73 diluent was switched and circulated.

[0205] The OK73 diluent after liquid permeation was spin-coated onto a 12-inch wafer and baked at 80°C for 60 seconds. Then, the number of defects larger than 19 nm was measured using the aforementioned wafer surface defect device, and the result showed that the number of defects had been reduced to 191.

[0206] (Examples 3-5) The washing solution of Reference Example 1 was replaced with the washing solution of Example 5 and the solution was circulated. After soaking in the piping of the aforementioned drug supply line for 1 day, 1L of the washing solution of Example 5 was circulated, and then OK73 diluent was switched and 1L was circulated.

[0207] The OK73 diluent after liquid permeation was spin-coated onto a 12-inch wafer and baked at 80°C for 60 seconds. Then, the number of defects larger than 19 nm was measured using the aforementioned wafer surface defect device, and the result showed that the number of defects had been reduced to 150.

[0208] (Examples 3-6) The washing solution of Reference Example 1 was replaced with the washing solution of Example 6 and the solution was circulated. After soaking in the piping of the aforementioned drug supply line for 1 day, 1L of the washing solution of Example 6 was circulated, and then OK73 diluent was switched and 1L was circulated.

[0209] The OK73 diluent after liquid permeation was spin-coated onto a 12-inch wafer and baked at 80°C for 60 seconds. Then, the number of defects larger than 19 nm was measured using the aforementioned wafer surface defect device, and the result showed that the number of defects had been reduced to 181.

[0210] (Examples 3-7) The washing solution of Reference Example 1 was replaced with the washing solution of Example 7 and the solution was circulated. After soaking in the piping of the aforementioned drug supply line for 1 day, 1L of the washing solution of Example 7 was circulated, and then OK73 diluent was switched and 1L was circulated.

[0211] The OK73 diluent after liquid permeation was spin-coated onto a 12-inch wafer and baked at 80°C for 60 seconds. Then, the number of defects larger than 19 nm was measured using the aforementioned wafer surface defect device, and the result showed that the number of defects had been reduced to 123.

[0212] (Comparative Example 3-1) The washing solution of Reference Example 1 was replaced with the washing solution of Comparative Example 1 and the solution was circulated. After soaking in the piping of the aforementioned drug supply line for 1 day, 1L of the washing solution of Comparative Example 1 was circulated, and then OK73 diluent was switched and 1L was circulated.

[0213] The OK73 diluent after liquid permeation was spin-coated onto a 12-inch wafer and baked at 80°C for 60 seconds. Then, the number of defects larger than 19 nm was measured using the aforementioned wafer surface defect device, and the result showed that the number of defects had been reduced to 4172.

[0214] (Comparative Example 3-2) The washing solution of Reference Example 1 was replaced with the washing solution of Comparative Example 2 and the solution was circulated. After soaking in the piping of the aforementioned drug supply line for 1 day, 1L of the washing solution of Comparative Example 2 was circulated. Then, OK73 diluent, which is different from the washing solution of Comparative Example 2, was switched and 1L of solution was circulated.

[0215] The OK73 diluent after liquid permeation was spin-coated onto a 12-inch wafer and baked at 80°C for 60 seconds. Then, the number of defects larger than 19 nm was measured using the aforementioned wafer surface defect device, and the result showed that the number of defects had been reduced to 3401.

[0216] (Comparative Example 3-3) The washing solution of Reference Example 1 was replaced with the washing solution of Comparative Example 3 and the solution was circulated. After soaking in the piping of the aforementioned drug supply line for 1 day, 1L of the washing solution of Comparative Example 3 was circulated, and then 1L of OK73 diluent was switched and circulated.

[0217] The OK73 diluent after liquid permeation was spin-coated onto a 12-inch wafer and baked at 80°C for 60 seconds. Then, the number of defects larger than 19 nm was measured using the aforementioned wafer surface defect device, and the result showed that the number of defects had been reduced to 4512.

[0218] [Table 4] The results shown in Table 4 confirm that when the washing solutions of Examples 1 to 7 are used, the number of defects on the wafer surface is significantly reduced compared to when the washing solutions of Comparative Examples 1 to 3 are used. Therefore, the removal of organic impurities and dirt in the piping after SOG solution is passed through can be improved by using the washing solutions of the present invention.

[0219] In the <Washing Evaluation (3)>, it was also confirmed that although the washing liquids of Examples 1 to 7 were obtained by further adding a specific amount of organic matter to the composition of the washing liquid of Reference Example 1, they had the same good washing performance as the washing liquid of Reference Example 1.

[0220] The preferred embodiments of the present invention have been described above, but the present invention is not limited to these embodiments. Additions, omissions, substitutions, and other modifications can be made to the structure without departing from the spirit of the present invention. The present invention is not limited by the foregoing description, but only by the scope of the appended claims.

Claims

1. A washing solution, which is a washing solution containing solvents and metal removal agents. The washing solution contains two or more solvents. The distance (HSP distance) between the Hansen solubility parameter of the washing solution and the Hansen solubility parameter of dimethylacetamide is less than 1.

0. The total content of organic matter selected from the group consisting of organic acid polymers, organic acid esters, and ketone bodies is 0.1 × 10⁻¹⁰ parts by mass relative to the total 100 parts by mass of the solvent and the metal removal agent. -9 10 or more by weight 5 ×10 -6 The weight is below 100 parts.

2. The washing liquid as described in claim 1, wherein, The distance (HSP distance) is less than 0.

5.

3. The washing liquid as described in claim 1, wherein it contains two or more of the metal removal agents.

4. The washing liquid as described in claim 1, wherein, The metal removal agent contains organic acids.

5. The washing liquid as described in claim 4, wherein, The organic acid is a carboxylic acid.

6. The washing solution as described in claim 1, used for washing objects selected from the group consisting of metal piping, resin piping, glass piping, metal fittings, resin fittings, glass fittings, filters, pharmaceutical containers, measuring cells, and chromatographic columns.

7. Washing methods, among which, The washing liquid according to any one of claims 1 to 6 is brought into contact with the object to be washed, thereby washing the object.

8. The washing method as described in claim 7, wherein, The objects to be washed are selected from the group consisting of metal piping, resin piping, glass piping, metal connectors, resin connectors, glass connectors, filters, pharmaceutical containers, measuring cells, and chromatographic columns.

9. The washing method as described in claim 7, wherein, Before or after the step of washing the object by contacting the washing liquid according to any one of claims 1 to 6 with the object to be washed, there is a step of washing the object by contacting a second washing liquid different from the washing liquid with the object to be washed.

10. The washing method as described in claim 9, wherein, The second washing solution contains an alcohol-based solvent.

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