Cleaning fluid and cleaning method

Abstract

To provide: a cleaning fluid having improved removability of stains due to impurities: and a cleaning method using the cleaning fluid.SOLUTION: Provided is a cleaning fluid, comprising a solvent and a metal remover. The cleaning fluid includes two or more kinds of solvents, the distance (HSP distance) between the Hansen solubility parameter of the cleaning fluid and the Hansen solubility parameter of dimethylacetamide is 1.0 or less, and the content of metal impurities is 0.1×10-9 pts.mass or more to 102×10-6 pts.mass or less relative to 100 pts.mass in total of the solvent and the metal remover.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a cleaning solution and a cleaning method. [Background technology]

[0002] The cleaning solution must be selected according to the type of dirt and the material of the object to be cleaned. In the industrial field, for example, in films, particularly porous films, produced from polymeric materials, the effects of organic impurity contamination such as polymer residues derived from the polymeric materials, or metal impurity contamination derived from metal catalysts used in the film production process, can be problematic. To address this problem, a membrane cleaning solution has been proposed in which a specific solvent is selected to suit the material of the film (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-202479 A Summary of the Invention [Problem to be solved by the invention]

[0004] Conventionally, in filters manufactured from porous films, the chemical solution purified by the filter may be contaminated unintentionally. The source of contamination is high molecular or low molecular organic impurities or metal impurities coexisting in the filter. These impurities are not only derived from the polymer material or metal catalyst, but are also likely to be mixed in from various places such as each pipe in the production line, the containers used, and the equipment. On the other hand, with the miniaturization and high performance of industrial products, there is a strong demand for further reduction of the above-mentioned impurity contamination. The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a cleaning liquid having improved ability to remove impurities and a cleaning method using the cleaning liquid. [Means for solving the problem]

[0005] In order to solve the above problems, the present invention employs the following configuration.

[0006] A first aspect of the present invention is a cleaning solution containing a solvent and a metal remover, the cleaning solution containing two or more solvents, the distance between the Hansen solubility parameter of the cleaning solution and the Hansen solubility parameter of dimethylacetamide (HSP distance) being 1.0 or less, and the content of metal impurities is 0.1×10 -9 Mass part or more 10 2 ×10 -6 parts by weight or less.

[0007] A second aspect of the present invention is a cleaning method, comprising contacting an object with the cleaning liquid according to the first aspect, thereby cleaning the object. Effect of the Invention

[0008] According to the present invention, it is possible to provide a cleaning liquid having improved ability to remove impurities and a cleaning method using the cleaning liquid. Such a cleaning solution and a cleaning method using the same are useful for removing impurities and dirt from various objects to be cleaned. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] (First aspect: cleaning solution) One embodiment of the cleaning solution contains two or more solvents and a metal removing agent. In this embodiment, the distance (HSP distance) between the Hansen solubility parameter of the cleaning liquid and the Hansen solubility parameter of dimethylacetamide is 1.0 or less. In addition, in the cleaning solution of the present embodiment, the content of metal impurities is 0.1×10 -9 Mass part or more 10 2 ×10 -6 parts by mass or less.

[0010] <Solvent> The cleaning liquid of this embodiment contains two or more solvents. The solvent contained in the cleaning solution of the present embodiment can be appropriately selected from known organic solvents so that the HSP distance is 1.0 or less. Examples of the organic solvent 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. As described later, some organic solvents contain multiple types of functional groups in their structures that characterize the above-mentioned solvents, and in such cases, the term "solvent" refers to any type of solvent containing the functional groups contained in the organic solvent. For example, diethylene glycol monomethyl ether is considered to be either an alcohol solvent or an ether solvent in the above classification.

[0011] <Ketone solvents> Ketone solvents are organic solvents that contain a CC(=O)-C structure. Specific 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, diacetonyl alcohol, acetyl carbinol, acetophenone, methyl naphthyl ketone, and methyl amyl ketone (2-heptanone). The ketone solvent may be a cyclic ketone solvent, specifically, cyclohexanone (CH), methylcyclohexanone, isophorone, propylene carbonate, ethylene carbonate, dihydrolevoglucosenone (silene), etc.

[0012] <Ester-based solvents> Ester solvents are organic solvents that contain CC(=O)-OC in their structure. Specific examples of ester-based solvents include methyl acetate, butyl acetate, ethyl acetate, isopropyl acetate, amyl acetate, isoamyl acetate, ethyl methoxyacetate, ethyl ethoxyacetate, 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, 4-ethoxybutyl 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 lactate, butyl lactate, lactic acid Propyl, 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, and propyl 3-methoxypropionate. The ester solvent may be a cyclic ester solvent (lactone solvent). Specific examples of the lactone solvent include γ-butyrolactone (GBL), ε-caprolactone, γ-valerolactone, and δ-valerolactone.

[0013] <Alcohol-based solvent> An alcohol-based solvent is an organic solvent that contains an alcoholic hydroxyl group in its structure. An "alcoholic hydroxy group" means a hydroxy group bonded to a carbon atom of an aliphatic hydrocarbon group. Specific examples of alcohol-based solvents 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), and dipropylene glycol.

[0014] <Nitrile solvents> A nitrile solvent is an organic solvent that contains a nitrile group in its structure. Specific examples of the nitrile solvent include acetonitrile, propionitrile, valeronitrile, and butyronitrile.

[0015] <Amide-based solvents> An amide-based solvent is an organic solvent that contains an amide group in its structure. Specific examples of the amide solvent include chain amide solvents such as dimethylacetamide (DMAc), dimethylformamide, and tetramethylurea; and cyclic amide (lactam) solvents such as dimethylimidazolidinone, N-methylpyrrolidone, 1-ethyl-2-pyrrolidone, and 1-butyl-2-pyrrolidone.

[0016] ≪Ether solvent≫ Ether-based solvents are organic solvents that contain COC in their structure. Specific 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.

[0017] Sulfoxide solvents Sulfoxide solvents are organic solvents that contain a sulfinyl group -S(=O)- in their structure. A specific example of the sulfoxide solvent is dimethyl sulfoxide (DMSO).

[0018] Sulfone-based solvents Sulfone-based solvents are organic solvents that contain a sulfonyl group, -S(=O)2-, in their structure. Specific examples of sulfone-based solvents include sulfolane.

[0019] <Hydrocarbon solvents> The hydrocarbon solvent is a hydrocarbon solvent that is composed of a hydrocarbon that may be halogenated and has no substituents other than halogen atoms. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is preferred. Specific examples of the hydrocarbon solvent include n-nonane, n-decane, n-undecane, n-dodecane, n-tridecane, n-tetradecane, n-pentadecane, and n-hexadecane.

[0020] The two or more solvents in the cleaning solution of the present embodiment are preferably a mixed solvent of two or more solvents selected from the group consisting of ketone-based solvents, ester-based solvents, alcohol-based solvents, and ether-based solvents, more preferably a mixed solvent of two or more solvents selected from the group consisting of ketone-based solvents, ester-based solvents, and ether-based solvents, and even more preferably a mixed solvent containing two or more solvents selected from the group consisting of ester-based solvents and ether-based solvents. In this specification, the term "two or more solvents" refers to those that contain two types of compounds and may be two or more solvents of the same classification. For example, the two or more solvents may be a mixed solvent of 1-octanone and cyclohexanone, both of which are classified as ketone solvents.

[0021] <Metal remover> Examples of the metal remover contained in the cleaning solution of the present embodiment include a metal chelating agent and an organic acid.

[0022] <Metal chelating agents> Examples of the metal chelating agent in this embodiment include aminocarboxylic acid chelating agents such as ethylenediaminetetraacetic acid, nitrilotriacetic acid, and diethylenetriaminepentaacetic acid; phosphonic acid chelating agents such as 1-hydroxyethane-1,1-diphosphonic acid and nitrilotris(methylenephosphonic acid); and compound (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.

[0023] [ka] [In the formula, Ra 1 and Ra 2 are each independently an alkyl group having 1 to 3 carbon atoms. 3 and Ra 4 are each independently a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. 1 and Ya 2each independently represents a single bond, -O-, -S- or -N(Ra 5 )-. Ra 5 is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. n is an integer of 0 to 3.]

[0024] In the formula (a-1), Ra 1 ~Ra 5 Examples of the alkyl group having 1 to 3 carbon atoms include a methyl group, an ethyl group, a propyl group, and an isopropyl group. In the formula (a-1), Ra 1 and Ra 2 are each independently preferably a methyl group or an ethyl group, and more preferably a methyl group. Ra 3 and Ra 4 is preferably a hydrogen atom. Ya 1 is preferably a single bond or -O-, and more preferably a single bond. Ya 2 is preferably a single bond or -O-, and more preferably a single bond. n is preferably 1 or 2, and more preferably 1.

[0025] Among the above, compound (A1) is preferably acetylacetone (AcAc) or acetonylacetone, and more preferably acetylacetone (AcAc). In the cleaning solution of the present embodiment, the metal chelating agent may be used alone or in combination of two or more kinds.

[0026] ≪Organic acid≫ 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; sugar acids 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)phosphoric acid, and phosphoric acid.

[0027] Among 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. In the cleaning solution of the present embodiment, the organic acid may be used alone or in combination of two or more kinds.

[0028] The cleaning solution of the present embodiment preferably contains two or more types of metal removers. The cleaning liquid of the present embodiment preferably contains two or more metal removers selected from the group consisting of the above-mentioned metal chelating agents and organic acids, more preferably contains two or more metal removers selected from the group consisting of the above-mentioned compound (A1) and organic acids, and further preferably contains two or more metal removers selected from the group consisting of the above-mentioned compound (A1) and carboxylic acids.

[0029] In the cleaning liquid of the present embodiment, among the above, it is preferable to use the above-mentioned metal chelating agent and an organic acid in combination, it is more preferable to use the above-mentioned compound (A1) and an organic acid in combination, and it is even more preferable to use the above-mentioned compound (A1) and a carboxylic acid in combination.

[0030] <Optional ingredients> The cleaning solution of the present embodiment may contain optional components other than the above-mentioned solvent and metal remover, as long as the effects of the present invention are not impaired. Examples of the optional components include a pH adjuster and a surfactant.

[0031] [Hansen Solubility Parameter Distance (HSP Distance)] The cleaning solution of the present embodiment contains the above-mentioned two or more types of solvents and a metal remover, and the distance (HSP distance) between the Hansen solubility parameter of the cleaning solution 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. If the HSP distance of the cleaning solution of this embodiment is equal to or less than the above upper limit, the cleaning solution can improve its effect of removing impurities and dirt, regardless of the material of the object to be cleaned.

[0032] As used herein, the term "Hansen Solubility Parameter" refers to a theoretically calculated numerical constant that is a useful tool for predicting the ability of a solvent material to dissolve a particular solute. The Hansen solubility parameters are the following three experimentally and theoretically derived Hansen solubility parameters (δ d (dispersion force term), δ p (polar term) and δ h (hydrogen bonding term)) can be combined to provide a measure of the overall strength and selectivity of a material. The Hansen solubility parameter is expressed in units of MPa 0.5 Or (J / cc) 0.5 is granted. δ d : Energy derived from intermolecular dispersion forces δ p : Energy derived from polar forces between molecules δ h : Energy derived from hydrogen bonding forces between molecules

[0033] "Hansen Solubility Parameters" can be calculated, for example, by "Molecular Modeling Pro" software, version 5.1.9 (ChemSW, Fairfield Calif., www.chemsw.com) or Hansen Solubility from Dynacomp Software.

[0034] Since the cleaning solution of this embodiment is a mixture, the Hansen solubility parameter of the cleaning solution of this embodiment can be determined as follows. For example, 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 Remover B 2 (δ dB2 , δ pB2 , δ hB2 ) and a cleaning solution CS consisting of a solvent S 1 The amount of the solvent is a, 2 The compounding amount of b, metal remover B 1 The amount of the metal remover B is c. 2 When the blending amount of is d, δ of the cleaning solution CS dcs (dispersion force term), δ pcs (polar term) and δ hcs (Hydrogen bond term) is calculated by the following formula, where a+b+c+d=100. 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

[0035] The distance (HSP distance) between the Hansen solubility parameter of the cleaning solution CS (the cleaning solution of this embodiment) and the Hansen solubility parameter of dimethylacetamide (DMAc) is calculated by the following formula (1). HSP distance={4(δ dcs -δ dDMAc ) 2 +(δ pcs -δ pDMAc ) 2 +(δ hcs -δ hDMAc ) 2} 0.5 (1) In addition, the dispersion term of dimethylacetamide (δ dDMAc ) is 16.8, and the polar term (δpDMAc ) is 11.5, and the hydrogen bond term (δ hDMAc ) uses a value of 9.4.

[0036] The HSP distance in the cleaning solution of this embodiment is, for example, the dispersion force term (δ dDMAc ), polarity term (δ pDMAc ) and hydrogen bond term (δ hDMAc ) or by selecting a combination of components.

[0037] [Metal impurity content] The cleaning solution of the present embodiment has a metal impurity content of 0.1×10 -9 Mass part or more 10 2 ×10 -6 parts by mass or less, 0.25 x 10 -9 Mass part or more 1×10 -6 (1000×10 -9 ) parts by mass or less, and -9 Mass part or more 500×10 -9 Parts by mass or less are more preferable, and 0.75×10 -9 Mass part or more 100×10 -9 It is more preferable that the amount is less than 1×10 -9 Mass part or more 20×10 -9 Parts by weight or less are particularly preferred. In the cleaning solution of this embodiment, so long as the content of metal impurities is within the above range, the effect of the cleaning solution in removing impurities and dirt is further improved regardless of the material of the object to be cleaned.

[0038] The "metal impurities" contained in the cleaning solution of this embodiment refer to metal components including metal elements selected from the group consisting of Na, Ca, K, Fe, Ti, Al, Ni, Zn, Cr, and Mg. The "content of metal impurities" refers to the total content of metal components including metal elements selected from the group consisting of Na, Ca, K, Fe, Ti, Al, Ni, Zn, Cr, and Mg.

[0039] The mass of metal impurities in the cleaning solution is determined by inductively coupled plasma mass spectrometry. In practice, the metal elements to be measured are identified and their total amount is measured to determine the content (mass fraction) of metal impurities in the cleaning solution. The metal elements to be measured are, for example, 12 to 28 elements, and in addition to Na, Ca, K, Fe, Ti, Al, Ni, Zn, Cr, and Mg, further include any of the metal elements Li, V, Mn, Co, Cu, Ge, As, Sr, Zr, Mo, Ag, Cd, Sn, Sb, Ba, W, Au, and Pb.

[0040] The content of metal impurities in the cleaning solution can be adjusted by controlling the amount of metal impurities contained in the solvent or metal remover to be formulated; alternatively, it can be adjusted by mixing the solvent, metal remover, and optional components and then adding a metal element separately from these; alternatively, it can be adjusted by separating and removing excess metal element.

[0041] The cleaning solution of the present embodiment is a composition containing a mixed solvent of two or more solvents selected from the group consisting of ketone-based solvents, ester-based solvents, alcohol-based solvents, and ether-based solvents, the metal chelating agent described above, and the organic acid described above, wherein the HSP distance is 1.0 or less, and the content of metal impurities is 0.1×10 with respect to 100 parts by mass of the total of the mixed solvent, the metal chelating agent, and the organic acid. -9 Mass part or more 10 2 ×10 -6 Parts by mass or less of composition (X) are preferred.

[0042] The mixed solvent in the composition (X) is more preferably a mixed solvent of one or more solvents selected from the group consisting of ketone-based solvents and ester-based solvents (hereinafter also referred to as "solvent S1") and one or more solvents selected from the group consisting of alcohol-based solvents and ether-based solvents (hereinafter also referred to as "solvent S2"), still more preferably a mixed solvent of an ester-based solvent and an ether-based solvent, and particularly preferably a mixed solvent of a lactone-based solvent and an ether-based solvent.

[0043] For example, when the two or more solvents in the composition (X) are a mixed solvent of solvent S1 and solvent S2, the mixing ratio of solvent S1 to solvent S2 (solvent S1:solvent S2) is preferably 20:80 to 80:20 by mass, more preferably 30:70 to 70:30, and even more preferably 40:60 to 60:40.

[0044] Suitable combinations of two or more solvents in the composition (X) include a mixed solvent of one or more solvents selected from the group consisting of γ-butyrolactone, ε-caprolactone, and γ-valerolactone with one or more solvents selected from the group consisting of EGME, PGME, and PGEE; a mixed solvent of dihydrolevoglucosenone (silene) and PG, and the like. Among these, a suitable combination of two or more solvents is preferably a mixed solvent 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 mixed solvent of γ-butyrolactone and PGME.

[0045] The metal chelating agent in the composition (X) is preferably the compound (A1), and more preferably acetylacetone (AcAc). The organic acid in the composition (X) is preferably a carboxylic acid, more preferably a hydroxy acid, and further preferably lactic acid.

[0046] In the composition (X), the content of metal impurities is 0.1×10 to 100 parts by mass of the total of the mixed solvent, the metal chelating agent, and the organic acid. -9 Mass part or more 10 2 ×10 -6 parts by mass or less, 0.25 x 10 -9 Mass part or more 1×10 -6 (1000×10 -9 ) parts by mass or less, and -9 Mass part or more 500×10-9 Parts by mass or less are more preferable, and 0.75×10 -9 Mass part or more 100×10 -9 It is more preferable that the amount is less than 1×10 -9 Mass part or more 20×10 -9 Parts by weight or less are particularly preferred.

[0047] In the composition (X), the contents of the mixed solvent, the metal chelating agent, and the organic acid are appropriately selected so that the HSP distance is 1.0 or less. The content of the mixed solvent in the composition (X) is preferably from 90 to 99.5% by mass, more preferably from 95 to 99% by mass, based on the total amount of the composition (X).

[0048] The content of the metal chelating agent in the composition (X) is preferably from 0.1 to 9 mass %, more preferably from 0.5 to 9 mass %, and even more preferably from 0.5 to 5 mass %, based on the total amount of the composition (X). The proportion of the compound (A1) in the metal chelating agent is preferably 50 mass % or more, more preferably 75 mass % or more, and may be 100 mass % based on the total mass of the metal chelating agent.

[0049] The content of the organic acid in the composition (X) is preferably from 0.1 to 9 mass%, more preferably from 0.5 to 9 mass%, and even more preferably from 0.5 to 5 mass%, relative to 100 mass% of the total amount of the composition (X). The proportion of carboxylic acid in the organic acid is preferably 50% by mass or more, more preferably 75% by mass or more, and may be 100% by mass, based on the total mass of the organic acid.

[0050] The composition (X) may further contain the above-mentioned optional components, in addition to the mixed solvent, the metal chelating agent and the organic acid, as necessary.

[0051] The cleaning solution of the present embodiment is a cleaning solution that is useful for cleaning membranes. The form and shape of the membrane are not particularly limited, and examples thereof include a flat membrane, a hollow fiber membrane, a tubular membrane, a spiral membrane, and a thin film. The material of the membrane is not particularly limited, and examples thereof include polyolefins (polyethylene, polypropylene, etc.), polysulfones, polyacrylonitrile, polyamides, polyimides, polyvinyl alcohol, cellulose acetate, fluoropolymers, ceramics, and the like.

[0052] The cleaning solution of the present embodiment is also useful for removing impurities and dirt from various objects to be cleaned. Examples of the objects to be cleaned include pipes in a production line, containers used, and tools. For example, the cleaning solution of the present embodiment can be used to clean objects to be cleaned selected from the group consisting of metal pipes, resin pipes, glass pipes, metal joints, resin joints, glass joints, filters, chemical containers, measurement cells, and chromatography columns.

[0053] The cleaning solution of the present embodiment described above contains two or more types of solvents and a metal remover. In addition, the distance (HSP distance) between the Hansen solubility parameter of the cleaning solution and the Hansen solubility parameter of dimethylacetamide (DMAc) is 1.0 or less, and the content of metal impurities is 0.1×10 -9 Mass part or more 10 2 ×10 -6 parts by mass or less. Although the reason is unclear, this cleaning solution has a good cleaning and removing effect on both polar and non-polar objects to be cleaned by adjusting the Hansen solubility parameter of the entire cleaning solution to be close to that of DMAc and by containing a metal remover. In addition, since it contains a metal remover, it has excellent ability to remove metal impurity stains. Furthermore, the cleaning solution is intentionally made to contain a specific amount of metal impurities, which enhances the effect of removing impurities from various objects to be cleaned, and in particular, greatly enhances the effect of removing metal impurities.

[0054] (Second aspect: cleaning method) One embodiment of the cleaning method is a method for cleaning an object to be cleaned by bringing the above-mentioned cleaning liquid into contact with the object to be cleaned. The objects to be cleaned in the cleaning method of this embodiment include membranes, each pipe in a production line, containers used, tools, etc. For example, the objects to be cleaned may be membranes such as flat membranes, hollow fiber membranes, tubular membranes, spiral membranes, thin films, etc. Alternatively, the objects to be cleaned may be selected from the group consisting of metal pipes, resin pipes, glass pipes, metal joints, resin joints, glass joints, filters, chemical containers, measurement cells, and chromatography columns.

[0055] More specifically, examples of the cleaning operation in which the above-mentioned cleaning liquid is brought into contact with the object to be cleaned to clean the object include a method of immersing the object to be cleaned in the cleaning liquid and a method of spraying the cleaning liquid onto the object to be cleaned. The washing operation may be carried out only once or may be carried out multiple times. Furthermore, during the washing operation, the washing solution may be heated, or the washing operation may be performed at room temperature (for example, 23° C.).

[0056] The cleaning method of the present embodiment may include a drying step of drying the object cleaned by the above cleaning operation. In the drying step, a known method such as air drying at room temperature, heating the object in a thermostatic chamber, or vacuum drying can be applied.

[0057] According to the cleaning method of the present embodiment described above, the above-mentioned cleaning liquid is used, and therefore the cleaning method is excellent in removing organic impurities or metal impurities from various objects to be cleaned.

[0058] Another embodiment of the cleaning method is a method having a step of cleaning the object to be cleaned by contacting the object with the above-mentioned cleaning liquid (hereinafter also referred to as "cleaning step A"), before or after a step of cleaning the object to be cleaned by contacting the object with a second cleaning liquid different from the above-mentioned cleaning liquid (hereinafter also referred to as "cleaning step B").

[0059] In the cleaning method according to the other embodiment, (i) the method may include a step of cleaning an object to be cleaned by bringing a second cleaning liquid different from the above-mentioned cleaning liquid (referred to as a first cleaning liquid) into contact with the object to be cleaned, and a step of cleaning the object to be cleaned by bringing the first cleaning liquid into contact with the object to be cleaned that has been cleaned with the second cleaning liquid, (ii) the method may include a step of cleaning an object to be cleaned by bringing the above-mentioned cleaning liquid (first cleaning liquid) into contact with the object to be cleaned, and a step of cleaning the object to be cleaned by bringing a second cleaning liquid different from the first cleaning liquid into contact with the object to be cleaned after the object has been cleaned with the first cleaning liquid, (iii) The method may include a step of cleaning an object to be cleaned by bringing a second cleaning liquid different from the above-mentioned cleaning liquid (first cleaning liquid) into contact with the object to be cleaned, a step of cleaning the object to be cleaned by bringing the first cleaning liquid into contact with the object to be cleaned that has been cleaned with the second cleaning liquid, and a step of cleaning the object to be cleaned by bringing a third cleaning liquid different from the above-mentioned first cleaning liquid into contact with the object to be cleaned that has been cleaned with the first cleaning liquid. In (iii), the second cleaning solution and the third cleaning solution may be the same or different.

[0060] Cleaning process B Examples of a method for cleaning the object to be cleaned by contacting the object with a second cleaning liquid different from the above-mentioned cleaning liquid in cleaning step B include methods similar to those in the above-mentioned cleaning step A (such as a method of immersing the object to be cleaned in the cleaning liquid or a method of spraying the cleaning liquid onto the object to be cleaned). The washing step B may be carried out only once or multiple times before or after the washing step A.

[0061] ·Second cleaning solution, third cleaning solution The cleaning liquid (second cleaning liquid, third cleaning liquid) different from the above-mentioned cleaning liquid includes a cleaning liquid containing a solvent and not containing a metal removing agent. The cleaning liquid (second cleaning liquid, third cleaning liquid) typically includes a cleaning liquid consisting of a solvent only.

[0062] Examples of the solvent in the cleaning liquid (second cleaning liquid, third cleaning liquid) include polar solvents such as ketone-based solvents, ester-based solvents, alcohol-based solvents, nitrile-based solvents, amide-based solvents, ether-based solvents, sulfoxide-based solvents, and sulfone-based solvents; and non-polar solvents such as hydrocarbon-based solvents. Specific examples of the solvent include the same solvents as those in the cleaning liquids described above. The cleaning liquid (second cleaning liquid, third cleaning liquid) preferably contains an alcohol-based solvent among the above, more preferably contains an alcohol-based solvent having 1 to 5 carbon atoms, and further preferably contains 2-propanol (isopropanol).

[0063] As another embodiment of the cleaning method, a method having a cleaning step A and a step of cleaning the object to be cleaned by contacting the object to be cleaned with an alcohol-based solvent (preferably 2-propanol) before or after the cleaning step A is preferable.

[0064] Another embodiment of the cleaning method may further include a drying step of drying the object cleaned in the cleaning step A or the cleaning step B. The drying step can be carried out by known methods such as air drying at room temperature, placing the washed object in a thermostatic chamber and heating it, or vacuum drying.

[0065] According to another embodiment of the cleaning method described above, in addition to the above-mentioned cleaning step A, the cleaning method further includes a cleaning step B. Therefore, the effect of removing impurities adhering to the object to be cleaned is enhanced compared to the cleaning method having only the above-mentioned cleaning step A. EXAMPLES

[0066] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0067] <Preparation of cleaning solution> The components were mixed according to the composition shown in Table 1 to prepare the cleaning solution for each example.

[0068] Example 1 In the cleaning solution of Example 1, the content of metal impurities after mixing the components was measured in the "Metal Impurity Content Measurement" described later, and the total content of the 28 metal elements was 1.1 × 10 per 100 parts by mass of the solvent and metal remover. -9 It was parts by mass.

[0069] (Example 2 and Example 3) By adding a standard solution for metal analysis in solvents (Agilent Technologies, part number 5190-8715) as a mineral oil to the cleaning solution of Example 1, the content of metal impurities was 4.5 × 10 per 100 parts by mass of the total of the solvent and metal remover. -9 The cleaning solution of Example 2, which is parts by mass, and the content of metal impurities, 23.9 × 10 -9 The cleaning solutions of Example 3 were prepared in parts by mass.

[0070] (Comparative Example 1 and Comparative Example 2) OK73 thinner was used as the cleaning liquid in Comparative Example 1. The composition of OK73 thinner is a mixed solvent of PGMEA / PGME=30 / 70 (mass ratio). Isopropanol was used as the cleaning liquid in Comparative Example 2. The content of metal impurities in isopropanol was 2.5×10 per 100 parts by mass of the total of the solvent and the metal remover. -9 Parts by mass.

[0071] [Table 1]

[0072] The abbreviations in the table represent the following compounds. The numbers in brackets [ ] in the table indicate the blend amount (parts by mass). GBL: gamma-butyrolactone PGME: Propylene glycol monomethyl ether PGMEA: Propylene glycol monomethyl ether acetate AcAc: Acetylacetone LA: Lactic acid IPA: Isopropanol

[0073] [Calculating HSP distance] The Hansen solubility parameters of each component of the cleaning 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.

[0074] GBL dispersion term (δ dGBL ) is 18, and the polar term (δ pGBL ) is 16.6, and the hydrogen bond term (δ hGBL ) was set to a value of 7.4. PGME dispersion term (δ dPGME ) is 15.6, and the polar term (δ pPGME ) is 6.3, and the hydrogen bond term (δ hPGME ) used a value of 11.6. Dispersion term of AcAc (δ dAcAc ) is 16.1, and the polar term (δ pAcAc ) is 10, and the hydrogen bond term (δ hAcAc ) used a value of 6.2. Dispersion term of LA (δ dLA ) is 17, and the polar term (δ pLA ) is 8.3, and the hydrogen bond term (δ hLA ) used a value of 28.4.

[0075] PGMEA dispersion term (δ dPGMEA ) is 15.6, and the polar term (δ pPGMEA ) is 6.3, and the hydrogen bond term (δ hPGMEA ) used a value of 7.7. Dispersion term of IPA (δ dIPA ) is 16.3, and the polar term (δ pIPA ) is 6.8, and the hydrogen bond term (δ hIPA ) was set to a value of 6.5.

[0076] The dispersion force term (δ dt ), polarity term (δ pt ) and hydrogen bond term (δ ht ) was calculated as follows: δdt =(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

[0077] The dispersion force term (δ dt ), polarity term (δ pt ) and hydrogen bond term (δ ht ) was calculated as follows: 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

[0078] The dispersion force term (δ dt ), polarity term (δ pt ) and hydrogen bond term (δ ht ) was calculated as follows: δ dt =(δ dIPA ×100) / 100 δ pt =(δ pIPA ×100) / 100 δ ht =(δ hIPA ×100) / 100

[0079] The Hansen solubility parameters (MPa) of the cleaning solutions of Examples 1 to 3 0.5) and the Hansen solubility parameter of dimethylacetamide (MPa 0.5 ) was calculated using the following formula (1t): Dispersion term of dimethylacetamide (δ dDMAc ) is 16.8, and the polar term (δ pDMAc ) is 11.5, and the hydrogen bond term (δ hDMAc ) used a value of 9.4.

[0080] HSP distance={4(δ dt -δ dDMAc ) 2 +(δ pt -δ pDMAc ) 2 +(δ ht -δ hDMAc ) 2} 0.5 (1t)

[0081] Hansen solubility parameters (MPa) of the cleaning solutions of Comparative Examples 1 and 2 0.5 ) and the Hansen solubility parameter of dimethylacetamide (MPa 0.5 ) (HSP distance) was also calculated in the same manner as in Examples 1 to 3 above.

[0082] [Metal impurity content measurement] The content of metal impurities in the cleaning solution was measured using an inductively coupled plasma mass spectrometer (manufactured by Agilent Technologies, product name: ICP-MS 8900). The 28 metal elements measured were Na, Ca, K, Fe, Ti, Al, Ni, Zn, Cr, Mg, Li, V, Mn, Co, Cu, Ge, As, Sr, Zr, Mo, Ag, Cd, Sn, Sb, Ba, W, Au, and Pb, and the total was taken as the content (mass fraction) of metal impurities in the cleaning solution. Metal impurity stains in the cleaning evaluation described below, i.e., the total metal amount in the OK73 thinner, were also measured in the same manner as above.

[0083] <Cleaning evaluation (1)> The cleaning solution of each example was used for a porous polyethylene film as the cleaning object, and the cleaning method was performed as shown below to evaluate the removability of metal impurity stains. The results are shown in Table 2.

[0084] (Comparative Example 1-1) To the container, 100 mL of the cleaning solution of Comparative Example 1 (OK73 thinner) was added. There, 1000cm 2 A porous polyethylene film was placed in the solution and immersed for one day. The porous polyethylene film was then removed and the total metal content in the OK73 thinner was measured, which was 37.4 ppb.

[0085] (Example 1-1) To the vessel was added 100 mL of the cleaning solution of Example 1. There, 1000cm 2 A porous polyethylene film was placed in the solution and immersed for one day. Thereafter, the cleaning solution was discarded from the container, and isopropanol (containing 2.5 ppb of metal impurities) was added to rinse the porous polyethylene film. After rinsing, the isopropanol was discarded from the container and replaced with 100 mL of OK73 thinner (the cleaning liquid of Comparative Example 1), and the porous polyethylene film was immersed in the OK73 thinner for one day. The porous polyethylene film was then removed and the total metal content in the OK73 thinner was measured, which was found to be 0.6 ppb.

[0086] (Examples 1-2 and 1-3) Except for changing the cleaning solution of Example 1 to the cleaning solutions of Examples 2 and 3, the above-mentioned cleaning method was used in the same manner to evaluate the removability of metal impurity stains from objects to be cleaned. When the cleaning solution of Example 2 was used, the total metal content in the OK73 thinner was 0.1 ppb. When the cleaning solution of Example 3 was used, the total metal content in the OK73 thinner was 2.1 ppb.

[0087] (Comparative Example 1-2) To the container, 100 mL of the cleaning solution of Comparative Example 2 was added. There, 1000cm 2 A porous polyethylene film was placed in the solution and immersed for one day. Thereafter, the cleaning solution was discarded from the container, and isopropanol (containing 2.5 ppb of metal impurities) was added to rinse the porous polyethylene film. After rinsing, the isopropanol was discarded from the container and replaced with 100 mL of OK73 thinner (the cleaning liquid of Comparative Example 1), and the porous polyethylene film was immersed in the OK73 thinner for one day. The porous polyethylene film was then removed and the total metal content in the OK73 thinner was measured, which was found to be 15.7 ppb.

[0088] [Table 2]

[0089] From the results shown in Table 2, it can be confirmed that the total metal amount is smaller when the cleaning solutions of Examples 1 to 3 are used than when the cleaning solutions of Comparative Examples 1 and 2 are used, and therefore the cleaning solution and cleaning method of the present invention can greatly improve the effect of removing metal impurity stains from the object to be cleaned.

[0090] <Cleaning evaluation (2)> The cleaning object was a chemical supply line (connected to a HDPE 2 nm filter, piping), and the cleaning method was used as shown below, using the cleaning solution of each example to evaluate the removability of impurities and dirt, using the number of defects on the wafer surface as an index. The results are shown in Table 3.

[0091] (Comparative Example 2-1) An HDPE 2 nm filter (Pall Corporation) was connected to the chemical supply line of a resist chemical coating and developing apparatus (Lithius ProZ, Tokyo Electron Ltd.), and 3GAL of the cleaning solution (OK73 thinner) of Comparative Example 1 was passed through it. OK73 thinner that had been passed through a HDPE 2 nm filter was applied to a 12-inch wafer and baked at 80°C for 60 seconds. After that, the number of defects 17 nm or larger was measured using a wafer surface defect analyzer (Surf Scan SP5 XP, manufactured by KLA Tencor). The number of defects when only OK73 thinner was passed through was 584.

[0092] (Example 2-1) An HDPE 2 nm filter (Pall Corporation) was connected to the chemical supply line of a resist chemical coating and developing apparatus (Lithius ProZ, Tokyo Electron Ltd.), and 1 GAL of the cleaning solution of Example 1 was passed through, and then OK73 thinner was used as the cleaning solution, and 2 GAL of the cleaning solution was passed through. The OK73 thinner that had been passed through this HDPE 2 nm filter was applied to a 12-inch wafer and baked at 80°C for 60 seconds. After that, the number of defects of 17 nm or more in size was measured using the wafer surface defect measurement device. When only OK73 thinner was passed through, the number of defects was 359, but this was reduced to 44.

[0093] (Example 2-2) The cleaning solution of Example 1 was replaced with the cleaning solution of Example 2 and allowed to pass through. After immersion in the chemical solution supply line for one day, 1 L of the cleaning solution of Example 2 was allowed to pass through, and then the solution was switched to OK73 thinner and 1 L was allowed to pass through. The OK73 thinner that had been passed through this was applied to a 12-inch wafer and baked at 80°C for 60 seconds. After that, the number of defects with a size of 17 nm or more was measured using the wafer surface defect measurement device, and the number of defects was reduced to 53.

[0094] (Example 2-3) The cleaning solution of Example 1 was replaced with the cleaning solution of Example 3 and allowed to pass through. After immersion in the chemical solution supply line for one day, 1 L of the cleaning solution of Example 3 was allowed to pass through, and then the solution was switched to OK73 thinner and 1 L was allowed to pass through. The OK73 thinner that had been passed through this was applied to a 12-inch wafer and baked at 80°C for 60 seconds. After that, the number of defects with a size of 17 nm or more was measured using the wafer surface defect measurement device, and the number of defects was reduced to 47.

[0095] [Table 3]

[0096] From the results shown in Table 3, it can be seen that when the cleaning solutions of Examples 1 to 3 were used, the number of defects on the wafer surface was reduced compared to when only the cleaning solution of Comparative Example 1 was used. This confirms that the application of the present invention can enhance the effect of removing impurity stains from the object to be cleaned.

[0097] Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments. Addition, omission, substitution, and other modifications of the configuration are possible without departing from the spirit of the present invention. The present invention is not limited by the above description, but is limited only by the scope of the attached claims.

Claims

1. A cleaning solution comprising a solvent and a metal remover, Contains two or more solvents, 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 content of metal impurities is 0.1×10 per 100 parts by mass of the total of the solvent and the metal remover. －９ 10 parts by mass or more ２ ×10 －６ parts by weight or less of a cleaning solution.

2. 2. The cleaning solution according to claim 1, wherein the metal impurities include at least one metal element selected from the group consisting of Na, Ca, K, Fe, Ti, Al, Ni, Zn, Cr and Mg.

3. The cleaning solution according to claim 1 , wherein the distance (HSP distance) is 0.5 or less.

4. The cleaning solution according to claim 1 , comprising two or more types of said metal removers.

5. The cleaning solution of claim 1 , wherein the metal remover comprises an organic acid.

6. The cleaning solution of claim 5 , wherein the organic acid is a carboxylic acid.

7. 2. The cleaning solution according to claim 1, which is used for cleaning an object to be cleaned selected from the group consisting of metal piping, resin piping, glass piping, metal joints, resin joints, glass joints, filters, chemical containers, measurement cells, and chromatography columns.

8. A cleaning method comprising contacting an object with the cleaning liquid according to any one of claims 1 to 7, thereby cleaning the object.

9. 9. The cleaning method according to claim 8, wherein the object to be cleaned is selected from the group consisting of a metal pipe, a resin pipe, a glass pipe, a metal joint, a resin joint, a glass joint, a filter, a chemical container, a measurement cell, and a chromatography column.

10. The cleaning method according to claim 8, further comprising a step of cleaning the object by contacting the cleaning liquid according to any one of claims 1 to 7 with the object, the step of cleaning the object by contacting the object with a second cleaning liquid different from the cleaning liquid.

11. The cleaning method according to claim 10 , wherein the second cleaning liquid contains an alcohol-based solvent.

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