Cleaning solution and cleaning method

Abstract

To provide a cleaning liquid that is capable of cleaning solid matter formed from dried coloration ink.SOLUTION: A cleaning liquid contains at least one compound selected from compounds represented by the following formula (1) and formula (2), and water. R1-(EO)m1(PO)n1H (1) [In the formula (1), R1 is a linear or branched C1-C30 alkyl group. EO is an ethyleneoxy group, PO is a propyleneoxy group. m1 and n1 are each an integer of 1-6. The ratio between m1 and n1, m1: n1, is 1: 2 or more and 3: 2 or less. EO and PO are bound to each other in any order]. [In the formula (2), R2 is a linear or branched C1-C30 alkyl group. OP is an oxypropylene group and OE is an oxyethylene group. m2 is an integer of 1-2 and n2 is an integer of 1-15. OP and OE are bound to each other in any order].SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a cleaning liquid, particularly to a cleaning liquid used for cleaning an inkjet printer, and to a cleaning method using the same. [Background technology]

[0002] A printing method using an inkjet printer (inkjet printing method) is a method in which small droplets of ink are generated and deposited on a recording medium such as paper to perform printing. In recent years, the inkjet printing method has been increasingly applied to industrial applications. The colorants contained in inkjet inks are broadly classified into water-soluble colorants and water-insoluble colorants. Of these, water-insoluble colorants such as pigments are generally superior in various fastness properties compared to water-soluble colorants. For this reason, inkjet inks for industrial use often contain water-insoluble colorants.

[0003] Recording media used for industrial applications are diversified, including various types of paper, fiber, and film. Many recording media are non-ink absorbing, such as resin film, and poorly ink absorbing, such as coated paper. Non-aqueous solvent inks and curable inks are known as inks used for printing on such recording media. However, from the viewpoint of safety, for example, to the natural environment and living organisms, there is a strong demand for aqueous inks to replace these inks. Such aqueous inks contain water-insoluble colorants and dispersants, and also generally contain polymers and waxes for the purpose of improving abrasion resistance and solvent resistance. For this reason, such aqueous inks have a high solid content and are extremely easy to dry. Drying of the ink causes the formation of solids in the nozzles and ink flow paths of the inkjet head during long-term storage, storage in high temperature and low humidity environments, etc., and is prone to clogging. When clogging occurs in the inkjet head in this way, the ink cannot be ejected stably. This causes problems such as deterioration of print quality and reduction in image density. For this reason, industrial inkjet heads are generally equipped with a cap member on the nozzle to prevent the ink from drying out, etc. However, when the environment in which the inkjet printer operates is harsh, it is difficult to completely prevent the ink from drying out.

[0004] In view of the above circumstances, there is a strong demand for a cleaning liquid (also called a cleaning liquid or a maintenance liquid) that can clean the inkjet head even when the ink dries and generates solid matter, causing clogging of the inkjet head. Patent documents 1 to 6 disclose cleaning liquids used for cleaning inkjet recording devices. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 5027444 [Patent Document 2] Patent No. 4649823 [Patent Document 3] Patent No. 4397220 [Patent Document 4] Patent No. 5618250 [Patent Document 5] Patent No. 5819206 [Patent Document 6] Patent No. 5819205 Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present invention is to provide a cleaning liquid capable of cleaning away solid matter even when colored ink dries and produces solid matter. [Means for solving the problem]

[0007] As a result of intensive research aimed at solving the above-mentioned problems, the present inventors have found that the above-mentioned problems can be solved by a cleaning solution containing at least a compound represented by the following formula (1) and / or the following formula (2) and water, and have completed the present invention. That is, the present invention relates to the following 1) to 4).

[0008] 1) A cleaning solution comprising water and one or more compounds selected from compounds represented by the following formulas (1) and (2):

[0009] [ka]

[0010] [In formula (1), R 1 represents a linear or branched C1-C30 alkyl group. EO represents an ethyleneoxy group, and PO represents a propyleneoxy group. m1 and n1 represent integers of 1 to 5. The ratio of m1 to n1, m1:n1, is 1:2 or more and less than 3:2. In addition, the order in which EO and PO are bonded is arbitrary.]

[0011] [ka]

[0012] [In formula (2), R 2 represents a linear or branched C1-C30 alkyl group. OP represents an oxypropylene group, and OE represents an oxyethylene group. m2 represents an integer of 1 to 2, and n2 represents an integer of 1 to 15. In addition, the order in which OP and OE are bonded is arbitrary.] 2) The cleaning solution according to 1) further contains one or more glycol ethers. 3) 1) Use of the cleaning solution according to 1) or 2) in cleaning an inkjet printer. 4) A method for cleaning an inkjet printer, comprising cleaning solid matter of inkjet ink adhering to the inkjet printer with the cleaning solution according to 1) or 2). Effect of the Invention

[0013] According to the present invention, even when colored ink dries and produces solid matter, a cleaning liquid capable of cleaning the solid matter can be provided. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] In this specification, unless otherwise specified, all "%" and "parts" are based on mass.

[0015] In the above formula (1), EO represents an ethyleneoxy group, and PO represents a linear or branched propyleneoxy group. R 1 is a straight-chain or branched alkyl group, usually C1-C30, preferably C10-C18, more preferably C12-C15. Among them, the straight-chain alkyl group is preferred. m1 and n1 each independently represent an integer of 1 to 6. The ratio of m1:n1 is usually in the range of 1:2 or more and 3:2 or less. The number and ratio of m1:n1 are preferably 1:2, 2:3, 3:4, 4:5, 5:6, 6:6, 5:5, 4:4, 3:3, 2:2, 1:1, 6:5, 5:4, 4:3, and 3:2, and among these, 4:4 is more preferable. Both m1 and n1 are average values. Therefore, in this specification, when m1 and n1 have decimal values, the values ​​are rounded off to the nearest integer to represent the values ​​of m1 and n1. The content of the compound represented by formula (1) in the total mass of the cleaning solution is usually 0.1% to 2%, and preferably 0.5% to 1%. The compound represented by formula (1) can be synthesized by a known method. It is also available as a commercial product. Specific examples of commercial products include GENAPOLEP2424 and EP2544 manufactured by Clariant. In addition, in the above formula (1), the order in which EO and PO are bonded is arbitrary and is not limited to the order represented by formula (1), but is preferably the order represented by formula (1).

[0016] [Compound represented by formula (2)] In the above formula (2), OP represents a linear or branched oxypropylene group, and OE represents an oxyethylene group. R 2 is a straight or branched chain, usually C1-C30, preferably C7-C13, more preferably C7-C10, further preferably C8-C10, particularly preferably C9 alkyl group. Of these, straight chain alkyl groups are preferred. m2 represents an integer of 1 to 2, and n2 represents an integer of 1 to 15, preferably an integer of 2 to 8. The ratio of m2:n2 is more preferably 1:4 or 2:4. Both m2 and n2 are average values. Therefore, in this specification, when m2 and n2 have decimal values, the values ​​are rounded off to one decimal place to an integer, and the values ​​are the values ​​of m2 and n2. The content of the compound represented by formula (2) in the total mass of the cleaning solution is usually 0.1% to 2%, and preferably 0.5% to 1%. The compound represented by formula (2) can be synthesized by a known method. It is also available as a commercial product. Specific examples of commercial products include Lutensol XL40 manufactured by BASF. In addition, in the above formula (2), the order in which OP and OE are bonded is arbitrary and is not limited to the order represented by formula (2). The order represented by formula (2) is preferable.

[0017] The above cleaning solution may further contain one or more compounds selected from the compounds represented by the following formula (3) and formula (4).

[0018] [ka]

[0019] R 3 is an alkyl group or an aryl group. R 3 The alkyl group in the formula (I) is a straight-chain or branched-chain alkyl group, usually C1-C30, preferably C10-C28, more preferably C10-C26, further preferably C10-C24, in some cases more preferably C12-C24, particularly preferably C13-C22. Among the alkyl groups, a straight-chain alkyl group is preferred. R 3 The aryl group in is a C6-C14 aryl group, preferably a C6-C10 aryl group, more preferably a phenyl group. R 3 The aryl group in the formula (I) may further have a substituent. The number of the substituents is usually 1 to 5, preferably 1 to 4, more preferably 1 to 3, further preferably 1 or 2, and particularly preferably 2. The substituent includes an arylalkyl group, preferably a C6-C14 aryl C1-C6 alkyl group; more preferably a C6-C10 aryl C1-C4 alkyl group; even more preferably a C6-C10 aryl C1-C3 alkyl group; in some cases more preferably a C6-C10 aryl C1-C2 alkyl group; and particularly preferably a phenethyl group (phenylethyl group). EO represents an ethyleneoxy group. L3 is an integer of 10 or more, preferably 10 to 30, more preferably 10 to 26, even more preferably 10 to 22, and in some cases more preferably 10 to 20, and particularly preferably 13 to 18. Since L3 is an average value, it may not be an integer but may have a decimal value. In this specification, in such cases, the value obtained by rounding off the first decimal place to an integer is regarded as the value of L3. The content of the compound represented by the above formula (3) in the total mass of the cleaning liquid is 0.2% to 2%. The compound represented by formula (3) can be synthesized by a known method. It is also available as a commercial product. Specific examples of commercial products include GENAPOLX150 manufactured by Clariant and Emulgen A90 manufactured by Kao Corporation.

[0020] [ka]

[0021] In the above formula (4), EO represents an ethyleneoxy group, and PO represents a linear or branched propyleneoxy group. m4, n4, and L4 each independently represent an integer of 1 or more, and the upper limit is not particularly limited, but usually m4 is 11 or more and 40 or less, n4 is 25 or more and 58 or less, and L4 is 11 or more and 40 or less; preferably m4 is 11 or more and 39 or less, n4 is 27 or more and 58 or less, and L4 is 11 or more and 39 or less; more preferably m4 is 13 or more and 37 or less, n4 is 29 or more and 56 or less, and L4 is 13 or more and 37 or less. m4, n4, and L4 satisfy the condition of the following formula (5). In the following formula (5), the upper limit of (m4+L4) / (m4+n4+L4)×100 is usually 76, preferably 71, and more preferably 62. The lower limit is usually greater than 27, and preferably 28 or more. The range of these upper and lower limits is usually 27 to 76, preferably 28 to 71, more preferably 35 to 62, even more preferably 40 to 60, and in some cases more preferably 45 to 60, and particularly preferably 47 to 57. m4, n4, and L4 are all average values. Therefore, in this specification, when m4, n4, and L4 have decimal values, the values ​​are rounded off to the nearest integer to represent the values ​​of m4 and n4. In addition, in this specification, when the calculation result of formula (5) has a decimal value, the calculation result is rounded off to one decimal place.

[0022] [ka]

[0023] The content of the compound represented by formula (4) in the total mass of the cleaning solution is usually 0.2% to 2%, preferably 0.4% to 2%. When the content in the cleaning solution is within the above range, a uniform cleaning solution is obtained, and excellent cleaning ability is obtained. The compound represented by formula (4) can be synthesized by a known method. It is also available as a commercial product. Specific examples of commercial products include GENAPOL PF40 manufactured by Clariant and Epane U-105 manufactured by Daiichi Kogyo Seiyaku Co., Ltd. In addition, in formula (4), the order in which EO and PO are bonded is arbitrary and is not limited to the order represented by formula (4), but is preferably the order represented by formula (4).

[0024] By containing one or more compounds selected from the compounds represented by the above formula (1) and formula (2), a cleaning liquid having high cleaning ability can be obtained. In addition, a cleaning solution further containing one or more compounds selected from the compounds represented by the above formulas (3) and (4) can provide a cleaning solution that has high cleaning ability as well as good storage stability.

[0025] [Organic solvents] The cleaning solution may further contain an organic solvent. It won't be done. Examples of organic solvents include C1-C6 alkanols having one hydroxyl group, such as methanol, ethanol, propanol, isopropanol, butanol, isobutanol, secondary butanol, and tertiary butanol; amides, such as N,N-dimethylformamide and N,N-dimethylacetamide; lactams, such as 2-pyrrolidone, N-methyl-2-pyrrolidone, and N-methylpyrrolidin-2-one; cyclic ureas, such as 1,3-dimethylimidazolidin-2-one and 1,3-dimethylhexahydropyrimid-2-one; ketones or ketoalcohols, such as acetone, 2-methyl-2-hydroxypentan-4-one, and ethylene carbonate; cyclic ethers, such as tetrahydrofuran and dioxane; ethylene glycol, diethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butylene glycol, 1,6-hexylene glycol, and the like. Examples of the alkylene glycol include mono-, oligo- or polyalkylene glycols or thioglycols having C2-C8 alkylene units, such as ethanol, 1,2-hexanediol, 1,2-pentanediol, 4-methyl-1,2-pentanediol, 3,3-dimethyl-1,2-butanediol, 1,2-octanediol, 5-methyl-1,2-hexanediol, 4-methyl-1,2-hexanediol, 4,4-dimethyl-1,2-pentanediol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, polyethylene glycol or polypropylene glycol having a molecular weight of 400 or more, thiodiglycol or dithiodiglycol, polyols (triols) such as glycerin, diglycerin, hexane-1,2,6-triol, and trimethylolpropane, γ-butyrolactone, and dimethyl sulfoxide, and glycol ethers. Among these, glycol ethers are preferred. The glycol ether is preferably a monoalkyl ether of a di- or tri-C2-C4 alkylene glycol. The C2-C4 alkylene glycol moiety includes ethylene glycol, propylene glycol, and butylene glycol, of which ethylene glycol and propylene glycol are preferred, and ethylene glycol is more preferred. The carbon number of the alkyl in the monoalkyl ether moiety is usually in the range of C1-C6, preferably C1-C5, more preferably C2-C4, further preferably C3-C4, and particularly preferably C4. Specific examples thereof include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether (butyl diglycol), triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, ethylene glycol monoallyl ether, ethylene glycol monoisopropyl ether, diethylene glycol monomethyl ether, propylene glycol monopropyl ether, triethylene glycol monobutyl ether, etc. Among these, butyl diglycol is preferred. The total content of organic solvents in the total mass of the cleaning liquid is usually 0 to 60%, preferably 0.1 to 50%, more preferably 0.2 to 40%, and even more preferably 0.5 to 30%. When the cleaning liquid contains at least glycol ether as an organic solvent, the total content of glycol ether is usually 0 to 15%, preferably 0.1 to 15%, more preferably 0.2 to 13%, and even more preferably 0.5 to 10%. When glycol ether and other organic solvents are used in combination, the sum of their total contents is the total content of the organic solvents in the total mass of the cleaning solution. In this case, the total content of glycol ethers is also as described above.

[0026] In addition to the above-mentioned components, the above-mentioned cleaning liquid may further contain various additives as necessary, such as surfactants, preservatives, antifungal agents, pH adjusters, chelating agents, rust inhibitors, water-soluble ultraviolet absorbers, antioxidants, etc. The total content of the preparations is usually about 0% to 30%, preferably 0% to 20%, and more preferably 0% to 10%, based on the total mass of the cleaning solution.

[0027] The cleaning solution is substantially free of colorants. In this specification, the term "substantially" means that no colorants are intentionally added to the cleaning solution.

[0028] [Surfactants] The surfactant may be anionic, cationic, nonionic, amphoteric, silicone-based, or fluorine-based surfactant. Of these, nonionic surfactants are preferred.

[0029] Examples of anionic surfactants include alkyl sulfocarboxylates, α-olefin sulfonates, polyoxyethylene alkyl ether acetates, polyoxyethylene alkyl ether sulfates, N-acylamino acids or salts thereof, N-acylmethyltaurines, alkyl sulfates, polyoxyalkyl ether sulfates, alkyl sulfates, polyoxyethylene alkyl ether phosphates, rosin acid soaps, castor oil sulfates, lauryl alcohol sulfates, alkylphenol phosphates, alkyl phosphates, alkylarylsulfonates, diethylsulfosuccinates, diethylhexylsulfosuccinates, and dioctylsulfosuccinates.

[0030] Examples of the cationic surfactant include 2-vinylpyridine derivatives and poly(4-vinylpyridine) derivatives.

[0031] Examples of nonionic surfactants include ester-based surfactants such as polyoxyethylene nonylphenyl ether, polyoxyethylene octylphenyl ether, polyoxyethylene dodecylphenyl ether, polyoxyethylene oleyl ether, polyoxyethylene lauryl ether, polyoxyethylene alkyl ether, polyoxyethylene distyrenated phenyl ether, polyoxyethylene oleate, polyoxyethylene distearate, sorbitan laurate, sorbitan monostearate, sorbitan monooleate, sorbitan sesquioleate, polyoxyethylene monooleate, and polyoxyethylene stearate; and 2,4,7,9-tetramethyl-5-decyne-4,7-diol, 3,6-dimethyl-4-octyne-3,6-diol, and 3,5-dimethyl-1-hexyne-3-ol.

[0032] Examples of amphoteric surfactants include lauryl dimethylaminoacetate betaine, 2-alkyl-N-carboxymethyl-N-hydroxyethyl imidazolinium betaine, coconut oil fatty acid amidopropyl dimethylaminoacetate betaine, polyoctyl polyaminoethyl glycine, and imidazoline derivatives.

[0033] Examples of the silicone surfactant include polyether-modified siloxane and polyether-modified polydimethylsiloxane.

[0034] Examples of fluorine-based surfactants include perfluoroalkyl sulfonic acid compounds, perfluoroalkyl carboxylic acid compounds, perfluoroalkyl phosphate compounds, perfluoroalkyl ethylene oxide adducts, and polyoxyalkylene ether polymer compounds having perfluoroalkyl ether groups on the side chains.

[0035] Examples of preservatives include organic sulfur, organic nitrogen sulfur, organic halogen, haloarylsulfone, iodopropargyl, haloalkylthio, nitrile, pyridine, 8-oxyquinoline, benzothiazole, isothiazolinone, dithiol, pyridine oxide, nitropropane, organic tin, phenol, quaternary ammonium salt, triazine, thiazine, anilide, adamantane, dithiocarbamate, brominated indanone, benzyl bromoacetate, or inorganic salt compounds.

[0036] Specific examples of antifungal agents include sodium dehydroacetate, sodium benzoate, sodium pyridinethione-1-oxide, p-hydroxybenzoic acid ethyl ester, 1,2-benzisothiazolin-3-one and salts thereof.

[0037] As the pH adjuster, any substance can be used as long as it can adjust the pH of the ink composition to 5 to 11 without adversely affecting the ink composition to be prepared. Specific examples of such an acid include alkanolamines such as diethanolamine, triethanolamine, and N-methyldiethanolamine; alkali metal hydroxides such as lithium hydroxide, sodium hydroxide, and potassium hydroxide; ammonium hydroxide (aqueous ammonia); alkali metal carbonates such as lithium carbonate, sodium carbonate, sodium hydrogen carbonate, and potassium carbonate; alkali metal salts of organic acids such as sodium silicate and potassium acetate; and inorganic bases such as disodium phosphate.

[0038] Specific examples of the chelating agent include disodium ethylenediaminetetraacetate, sodium nitrilotriacetate, sodium hydroxyethylethylenediaminetriacetate, sodium diethylenetriaminepentaacetate, and sodium uracildiacetate.

[0039] Specific examples of the rust inhibitor include acid sulfite, sodium thiosulfate, ammonium thioglycolate, diisopropylammonium nitrite, pentaerythritol tetranitrate, and dicyclohexylammonium nitrite.

[0040] Examples of the water-soluble ultraviolet absorber include sulfonated benzophenone compounds, benzotriazole compounds, salicylic acid compounds, cinnamic acid compounds, and triazine compounds.

[0041] Examples of the antioxidant include various organic and metal complex-based anti-fading agents. Examples of the organic anti-fading agents include hydroquinones, alkoxyphenols, dialkoxyphenols, phenols, anilines, amines, indanes, chromans, alkoxyanilines, and heterocycles.

[0042] The above-mentioned cleaning liquid can be obtained by adding the above-mentioned components and, if necessary, ink preparation agents, and thoroughly mixing them. The method for cleaning the inkjet printer is not particularly limited as long as it is a method for cleaning solids of inkjet ink adhering to the inkjet printer. A typical cleaning method includes, for example, a method in which a cleaning liquid is absorbed into a sponge or the like and the stains on the parts where colored ink is adhering are wiped off. On the other hand, for example, when the colored ink dries on the inkjet head and the inkjet head is heavily stained, the inkjet head can be cleaned by filling the inkjet head with a cleaning liquid instead of the colored ink. When cleaning the inkjet head by filling the cleaning liquid therein, it is preferable to precisely filter the cleaning liquid. When performing precision filtration, it is possible to use a membrane filter and / or glass filter paper, etc. The pore size of the filter, etc., used for precision filtration is usually 0.5 μm to 20 μm, preferably 0.5 μm to 10 μm.

[0043] The pH of the above cleaning liquid is usually from pH 5 to 11, and preferably from pH 7 to 10.5, in order to prevent corrosion of the inkjet printer components. The surface tension of the cleaning liquid is usually 10 mN / m to 50 mN / m, and preferably 20 mN / m to 40 mN / m. The viscosity of the cleaning liquid is usually 30 mPa·s or less, preferably 20 mPa·s or less, with the lower limit being approximately 0.1 mPa·s.

[0044] The cleaning solution can be used to clean water-based inks containing various colorants, such as water-soluble dyes such as acid dyes, direct dyes, and reactive dyes, and water-based inks containing water-insoluble colorants such as disperse dyes and pigments. The cleaning solution has a high cleaning power and is therefore preferably used for cleaning water-based inks containing water-insoluble colorants, particularly pigments. In addition, due to its high cleaning power, the cleaning solution exhibits extremely high performance as a cleaning solution for water-based inks containing various resins together with pigments.

[0045] All of the above-mentioned components can be used alone or in combination of two or more. In addition, for all of the above items, a combination of preferred items is more preferred, and a combination of more preferred items is even more preferred. The same applies to combinations of preferred items and more preferred items, and combinations of more preferred items and even more preferred items. EXAMPLES

[0046] The present invention will be described in detail below with reference to examples, but the present invention is not limited to the following examples. In addition, the cleaning liquid and the color ink were prepared under stirring unless otherwise specified. Furthermore, the "water" used in the examples is ion-exchanged water.

[0047] [Example 1~ 3 and Reference Example 1 ]:Preparation of cleaning solution. The components shown in Table 1 below were mixed to obtain a total of 100 parts of each liquid, and the obtained liquid was filtered through a 3 μm membrane filter to obtain the compositions of Examples 1 to 4. 3 and Reference Example 1 The cleaning solution was obtained as follows. 3 "EP2424", "EP2544", and "XL40" used in the above are compounds corresponding to the above formula (1) or formula (2).

[0048] [Comparative Examples 1 to 5]: Preparation of comparative cleaning solutions. The same procedures as in Examples 1 to 4 were repeated except that the components shown in Table 1 below were used. 3 and Reference Example 1 In the same manner, comparative cleaning solutions were obtained for Comparative Examples 1 to 5. "EP2584" used in Comparative Example 2 does not correspond to the above formula (1), and "SN465", "EP7025", and "LS106" are compounds that do not correspond to the above formula (2).

[0049] The abbreviations in Table 1 below have the following meanings. The numerical values ​​in Table 1 are in parts. Gly: Glycerin. 2Py: 2-pyrrolidone. BDG: butyl diglycol. EP2424: GENAPOLE P2424, a nonionic surfactant manufactured by Clariant. EP2544: GENAPOLE P2544, a nonionic surfactant manufactured by Clariant. EP2564: GENAPOLE P2564, a nonionic surfactant manufactured by Clariant. EP2584: GENAPOLE P2584, a nonionic surfactant manufactured by Clariant. XL40: Lutensol XL40 manufactured by BASF. SN465: Surfynol 465, a nonionic surfactant manufactured by Nissin Chemical Co., Ltd. EP7025: Softanol EP-7025, a nonionic surfactant manufactured by Nippon Shokubai Co., Ltd. LS106: Emulgen LS-106, a nonionic surfactant manufactured by Kao Corporation. A90: Emulgen A90, a nonionic surfactant manufactured by Kao Corporation. TEA: Triethanolamine. GXL(S): Proxel GXL(S) manufactured by Lonza.

[0050] EP2424 is represented by the formula (1), R 1 is a C12-C14 alkyl group, m1 is 1 to 3, n1 is 2 to 5, and m1:n1 is 1:2. EP2544 is represented by the formula (1), R 1 is a C12-C15 alkyl group, m1 is 2 to 4, n1 is 2 to 4, and m1:n1 is 1:1. EP2564 is R in the above formula (1). 1 is a C12-C15 alkyl group, m1 is 6, n1 is 4, and m1:n1 is 3:2. EP2584 is R in the above formula (1). 1 is a C12-C15 alkyl group, m1 is 8, n1 is 4, and m1:n1 is 2:1, so this compound is not included in the above formula (1). XL40 is R in the above formula (2). 2 is a 4-nonyl group, m2 is 1, and n2 is 4. Since SN465 is an acetylene glycol, it is not included in the above formula (1). EP7025 is R in the above formula (1). 1 is a C12-C15 branched alkyl group, m is 2.5, and n is 7, so this compound is not included in the above formula (1). LS106 is R 1 Although it has an alkyl group as the alkyl group and an oxyethylene group, it does not have an oxypropylene group (that is, m is 0), and therefore is not included in the above formula (1). A90 is calculated by the above formula ( 3 ) inside, R 3 is a phenyl group substituted with two 1-phenylethyl groups, L 3 There are 18 compounds.

[0051] [Table 1]

[0052] [Preparation Example 1]: Preparation of Resin A. 25 parts of Joncryl 678 (MW: 8500) and 14.3 parts of triethanolamine were dissolved in 60.7 parts of ion-exchanged water and stirred for one hour to obtain a solution. The obtained solution was designated as Resin A.

[0053] [Preparation Example 2]: Preparation of colored dispersion. A block copolymer described in Synthesis Example 3 of WO 2013 / 115071 was prepared, and 5 parts of the obtained polymer dispersant were dissolved in 20 parts of 2-butanone to obtain a homogeneous solution. A solution in which sodium hydroxide (0.4 parts) was dissolved in water (50.6 parts) was added to this liquid, and resin solution A (4 parts) was added, followed by stirring for 1 hour to obtain a liquid. CI Pigment Yellow 74 (20 parts, Clariant HANSAYELLOW5GX01-JP) was added to this liquid, and dispersion treatment was performed in a sand grinder under conditions of 1500 rpm to obtain a liquid. Water (100 parts) was dropped into the obtained liquid, and the liquid was filtered to obtain a filtrate. 2-butanone and a part of the water were distilled off under reduced pressure from the obtained filtrate using an evaporator to obtain a colored dispersion liquid with a pigment content of 12.4%. The pigment content in the color dispersion was calculated as the pigment content only from the total solids in the liquid by the dry weight method using an MS-70 manufactured by A&D Co., Ltd.

[0054] [Preparation Example 3] Preparation of Resin B. By following the procedure of Preparation Example 4 in WO 2015 / 147192, a resin emulsion having an acid value of 6 KOHmg / g, a Tg of 0°C, and a solid content of 25% was prepared. This is referred to as "Resin B".

[0055] [Preparation Example 4]: Preparation of colored ink. The components shown in Table 2 below were mixed to obtain a total of 100 parts of a liquid, and the obtained liquid was filtered through a 3 μm membrane filter to obtain a colored ink to be used for evaluating the cleaning liquid.

[0056] The abbreviations in Table 2 below have the following meanings. The numerical values ​​in Table 2 below are in parts. Dp1: Colored dispersion obtained in Preparation Example 2. TEG: triethylene glycol. 1,2HD: 1,2-hexanediol. SN465: Surfynol 465, a nonionic surfactant manufactured by Nissin Chemical Co., Ltd. AQ515: Polyethylene wax manufactured by BYK-Chemie, AQUACER 515 (solid content 35.0%). The parts numbers in Table 2 for Resin B and AQ515 are calculated as solid content values.

[0057] [Table 2]

[0058] [Stability test] The cleaning solutions obtained in each of the Examples and Comparative Examples were allowed to stand at room temperature for 12 hours, after which the state of the cleaning solutions was visually observed and their stability was evaluated. The evaluation criteria were the following two stages. The evaluation results are shown in Table 3 below. The cleaning test described below was carried out using only the cleaning solutions rated "A" in the stability test. [Evaluation Criteria] A: There was no change in the condition of the cleaning solution. C: Liquid components separated from the cleaning solution were observed floating on the surface of the cleaning solution.

[0059] [Washability test] 20 microliters of the colored ink obtained in Preparation Example 4 above was dropped onto a glass petri dish and left to stand in a thermostatic chamber at 60° C. for 1 hour to dry, thereby obtaining a solid product in which the colored ink had solidified. Ten milliliters of each of the cleaning solutions from the Examples and Comparative Examples was dropped onto the obtained solid matter, and whether the solid matter could be cleaned was visually evaluated. The evaluation criteria were the following four levels. The evaluation results are shown in Table 3 below. In Table 3, "-" indicates that the cleaning property test was not performed. [Evaluation Criteria] A: No remaining solid matter was observed, and the liquid became homogeneous. B: A small amount of solid matter remained, but the liquid was almost homogeneous. C: Solid matter clearly remained and the liquid was not homogeneous. D: The shape of the solid matter did not change at all or changed very little.

[0060] [Table 3]

[0061] As is clear from the above results, the cleaning solutions of the examples are confirmed to have excellent stability and cleaning properties. It was acknowledged. [Industrial Applicability]

[0062] The cleaning liquid of the present invention is extremely useful as a cleaning liquid for colored inks, particularly colored inks containing water-insoluble colorants, since it can clean solid matter even when the ink dries and produces solid matter.

Claims

1. A cleaning solution for an inkjet printer comprising water and one or more compounds selected from compounds represented by the following formula (1), wherein the cleaning solution further comprises butyl diglycol, and where the total mass of butyl diglycol in the cleaning solution is X and the total mass of the compounds represented by the following formula (1) is Y, a value calculated by X / Y is 10 to 30. 【Chemistry 1】 [In formula (1), R １ represents a linear or branched C1-C30 alkyl group. EO represents an ethyleneoxy group, and PO represents a propyleneoxy group. m1 represents an integer from 1 to 4, and n1 represents an integer from 1 to 5. The ratio of m1 to n1, m1:n1, is 1:2 or more and less than 3:

2. The order in which EO and PO are bonded is arbitrary.]

2. 10. The cleaning solution of claim 1 further comprising one or more glycol ethers.

3. 3. A method for cleaning an inkjet printer, comprising cleaning solid matter of inkjet ink adhering to the inkjet printer with the cleaning liquid according to claim 1.

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