Water-soluble metalworking oil, metalworking fluid, metalworking method, and method for improving dispersibility of water-soluble metalworking oil

Abstract

Provided are: a metalworking oil agent having improved dispersibility in water; and the like. The water-soluble metalworking oil agent contains a hydroxy compound represented by general formula (1), water, a base oil, and a surfactant. # imgabs0 #

Description

Technical Field

[0001] The present invention relates to a water-soluble metalworking oil, a metalworking fluid, a metalworking method and a method for improving the dispersibility of the water-soluble metalworking oil. Background Art

[0002] In the field of metalworking such as cutting and grinding, water-soluble metalworking oils are used. Water-soluble metalworking oils are often prepared by diluting a stock solution of the metalworking oil in water and using it as a metalworking fluid (diluent). A technique for improving the dispersibility of such a stock solution of the metalworking oil in water has been proposed.

[0003] For example, Patent Document 1 discloses a water-soluble metalworking oil composition which contains a hydroxy unsaturated fatty acid polymer and a tertiary amine in relatively high amounts, thereby reducing tool friction and extending tool life, and improving dispersibility in water and improving workability. Prior art literature Patent Literature

[0004] Patent Document 1: International Publication No. 2017 / 073553 Summary of the invention Technical problem to be solved by the invention

[0005] However, the water-soluble metalworking oil composition described in Patent Document 1 has room for improvement from the viewpoint of dispersibility. Reduced dispersibility in water leads to deterioration of workability when the stock solution is diluted in water and equipment contamination due to adhesion of inadequate emulsification products in equipment using the metalworking oil.

[0006] A main object of the present invention is to provide a metalworking oil having improved dispersibility in water. Technical solutions for solving technical problems

[0007] Means of the present invention for solving the above-mentioned problems are as follows.

[0008] [1] A water-soluble metalworking oil comprising a hydroxy compound represented by the following general formula (1), water, a base oil and a surfactant.

[0009]

[0010] [Where R 1 is a branched or cyclic hydrocarbon group or a linear unsaturated hydrocarbon group having 6 to 8 carbon atoms which may be substituted, R 2 is an alkylene group having 2 or 3 carbon atoms, and n is an integer of 0 to 2.] [2] The water-soluble metalworking oil according to [1], wherein in the general formula (1), R1 It is an aromatic group. [3] The water-soluble metalworking oil according to [1] or [2], wherein in the general formula (1), R 2 The number of carbon atoms in the alkylene group is 2. [4] The water-soluble metalworking oil according to any one of [1] to [3], wherein in the general formula (1), n ​​is 1 or 2. [5] The water-soluble metalworking oil according to any one of [1] to [4], wherein the content of the hydroxy compound is 1.5% by mass or more and 10% by mass or less. [6] The water-soluble metalworking oil according to any one of [1] to [5], wherein the mass ratio of the content of the hydroxy compound to the content of the surfactant (hydroxy compound / surfactant) is 0.05 or more and 1.0 or less. [7] The water-soluble metalworking fluid according to any one of [1] to [6], wherein the surfactant is at least one selected from a nonionic surfactant and an anionic surfactant. [8] A metalworking fluid obtained by diluting the water-soluble metalworking oil according to any one of [1] to [7] with water. [9] A metalworking method, comprising processing a workpiece containing metal using a metalworking fluid obtained by diluting the water-soluble metalworking fluid according to any one of [1] to [7] with water.

[10] A method for improving the dispersibility of a water-soluble metalworking oil, comprising the step of mixing a hydroxy compound represented by the following general formula (1), water, a base oil and a surfactant.

[0011]

[0012] [Where R 1 is a branched or cyclic hydrocarbon group or a linear unsaturated hydrocarbon group having 6 to 8 carbon atoms which may be substituted, R 2 is an alkylene group having 2 or 3 carbon atoms, and n is an integer of 0 to 2.] Effects of the Invention

[0013] According to the present invention, it is possible to provide a metalworking oil or the like having improved dispersibility in water. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is an image explaining the evaluation criteria of water dispersibility. DETAILED DESCRIPTION

[0015] Hereinafter, preferred embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments. The elements listed below can be combined arbitrarily, and the scope of the present invention is intended to include all changes in the claims and the scope equivalent to the claims. In addition, in this specification, the upper limit and lower limit of the numerical range can be arbitrarily combined to form a new numerical range. For example, in the case of "A or more and B or less" and "C or more and D or less", the range of "A or more and D or less" and "C or more and B or less" can also be included in the numerical range.

[0016] In this specification, when the number of carbon atoms in a group is specified, unless otherwise specified, the number of carbon atoms refers to the number of carbon atoms in the entire group. That is, when the group is in a form further having a substituent, it refers to the number of carbon atoms in the entire group including the substituent.

[0017] [Metalworking oil] The metalworking oil of the present embodiment contains a hydroxy compound represented by the following general formula (1) (hereinafter also referred to simply as a hydroxy compound), water, a base oil, and a surfactant.

[0018]

[0019] [Where R 1 is a branched or cyclic hydrocarbon group or a linear unsaturated hydrocarbon group having 6 to 8 carbon atoms which may be substituted, R 2 is an alkylene group having 2 or 3 carbon atoms, and n is an integer of 0 to 2.]

[0020] A metalworking oil agent, when the metalworking oil agent is used as a stock solution and diluted with water to form a metalworking fluid (diluted solution), can improve the dispersibility of the stock solution in water and inhibit the generation of coagulation (suspended matter). In this specification, the dispersibility in water refers to the property that particles in the metalworking oil agent are dispersed in water without coagulation.

[0021] The metalworking oil of the present embodiment contains a hydroxy compound to improve water dispersibility. The hydroxy compound functions as a dispersant. The mechanism of the excellent water dispersibility of the metalworking oil of the present invention is not yet clear, but is presumed as follows.

[0022] It is believed that the water and base oil in the oil solution containing water, base oil and surfactant are mixed in a small amount and overlapped in layers, which is a layered structure with fluidity. Surfactants are adsorbed on the water-oil interface. The surfactants are arranged in a manner that the hydrophilic part is arranged in the direction of the water layer and the lipophilic part is arranged in the direction of the oil layer. As the emulsification process of water dilution of the oil solution, the shear force acting on the diluent generates fluctuations at the water-oil interface, and the oil component at the oil interface becomes gradually rounded and is cut off from the part where the neck is generated, thereby forming oil droplets and generating O / W emulsions. The surfactants adsorbed on the water-oil interface interact with each other, and the stronger the interaction between the adsorbed molecules, the stronger the effect as a resistance to the deformation of the water-oil interface, and the more difficult it is to form an O / W emulsion. Therefore, it is speculated that by weakening the interaction between the adsorbed molecules, the formation of the O / W emulsion becomes easier, and the dispersibility and dilution of the oil solution can be improved.

[0023] The hydrophobic group constituting the hydroxyl compound has a structure with a larger volume than a straight-chain saturated structure, that is, a cyclic structure, a branched structure, or a straight-chain unsaturated structure. By allowing the hydroxyl compound having a large volume structure to be adsorbed on the water-oil interface, the intermolecular distance of the adsorbed molecules is expanded compared to the case where a compound having only a straight-chain saturated structure is adsorbed on the water-oil interface. As a result, it is presumed that the interaction between adjacent molecules acting on the hydrophobic group side can be weakened, the dispersibility of the oil solution is improved, and emulsification becomes easier.

[0024] In addition, by weakening the interaction of the hydroxy compound acting on the hydrophilic group side, water dispersibility can be further improved. For example, in the case of a metalworking oil containing a nonionic surfactant such as a polyoxyalkylene chain that plays a role between hydrophilic groups via a water molecule hydrogen bond, or a hydroxy compound having a high affinity with a polyoxyalkylene chain such as an aryl group, a part of the hydroxy compound penetrates into the dense region of the polyoxyalkylene chain present on the hydrophilic group side. By making the hydroxy compound penetrate into the hydrophilic group side, the network of the water molecules on the hydrophilic group side is disturbed, and the interaction (hydrogen bond) on the hydrophilic group side that plays a role as a resistance to deformation at the water-oil interface can be weakened. As a result, it is inferred that the dispersibility of the oil solution is improved, and emulsification becomes easy.

[0025] In this embodiment, in formula (1), R 1 It is a branched or cyclic hydrocarbon group or a linear unsaturated hydrocarbon group having 6 to 8 carbon atoms. 1 It may have a substituent.

[0026] In this specification, "hydrocarbon group" means a group obtained by removing one or more hydrogen atoms from a hydrocarbon having a specified number of carbon atoms. The hydrocarbon group may be substituted with one or more substituents, preferably unsubstituted. The substituent is not particularly limited, and examples thereof include alkyl groups having 1 to 3 carbon atoms (methyl, ethyl, propyl, etc.).

[0027] R 1 The hydrocarbon group is preferably branched or cyclic, and more preferably cyclic. The branched or cyclic hydrocarbon group may be either saturated or unsaturated. The cyclic hydrocarbon group may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group, and preferably an aromatic hydrocarbon group. The cyclic hydrocarbon group may be a polycyclic group or a monocyclic group.

[0028] In formula (1), as R 1 The term "alkenyl" or "alkenyl" refers to a branched, cyclic or linear unsaturated hydrocarbon group, or a branched or cyclic saturated hydrocarbon group, for example, a branched alkyl group, an alkenyl group, an alkenylene group, an aryl group, a cycloalkyl group, a cycloalkenyl group, a cycloalkylene group, a cycloalkynyl group, etc. "Alkenyl" and "alkenylene group" are not particularly limited, for example, monoolefins, dienes and triolefins, etc. are included. As the hydrocarbon group, from the viewpoint of water dispersibility, preferably a branched alkyl group or an aryl group, more preferably an aryl group.

[0029] As R 1 The hydrocarbon group having 6 to 8 carbon atoms includes, for example, ethylbutyl, methylpentyl, dimethylbutyl, methylhexyl, ethylpentyl, dimethylpentyl, methylheptyl, ethylhexyl, dimethylhexyl, phenyl, benzyl, dimethylphenyl, cyclohexyl, cycloheptyl and cyclohexenyl, preferably ethylhexyl, phenyl and benzyl.

[0030] From the viewpoint of water dispersibility, R 1 The hydrocarbon group preferably has 7 carbon atoms.

[0031] In formula (1), R 2 R is an unsubstituted alkylene group having 2 or 3 carbon atoms, and preferably an alkylene group having 2 carbon atoms from the viewpoint of water dispersibility. 2 For example, ethylene (-CH 2 CH 2 -), propylene (-CH 2 CH 2 CH 2 -、-CH(CH 3 )-CH 2 -, or -CH 2 CH(CH 3 )-, etc., preferably ethylene.

[0032] In formula (1), n ​​is an integer of 0 to 2. From the viewpoint of water dispersibility, n is preferably 0 or 1, more preferably 1.

[0033] In one embodiment, the hydroxy compound, in formula (1), R 1 is a cyclic hydrocarbon group having 6 or 7 carbon atoms, R 2 is an alkylene group having 2 or 3 carbon atoms, and n is 0 or 1.

[0034] In one embodiment, the hydroxy compound is, in formula (1), R 1 is a cyclic hydrocarbon group having 7 carbon atoms, R 2 is an alkylene group having 2 carbon atoms, and n is 0 or 1.

[0035] In one embodiment, the hydroxy compound is, in formula (1), R 1 is a branched saturated hydrocarbon group having 8 carbon atoms, R 2 is an alkylene group having 2 carbon atoms, and n is an integer of 0 to 2.

[0036] The hydroxy compound can be obtained by a known synthesis method. The hydroxy compound may be used alone or in combination of two or more.

[0037] Examples of the hydroxy compound include benzyl alcohol, ethylene oxide (hereinafter also referred to as EO) 1 mol addition product of benzyl alcohol, 2-phenoxyethanol, 2-phenoxyisopropanol, 2-ethylhexanol, monoethylene glycol mono-2-ethylhexyl ether, diethylene glycol, mono-2-ethylhexyl ether, and the like.

[0038] In the water-soluble metalworking oil, from the viewpoint of water dispersibility and emulsion stability, the content of the hydroxy compound is preferably 1.5% by mass or more and 10% by mass or less, more preferably 1.8% by mass or more and 9% by mass or less, further preferably 2.0% by mass or more and 8% by mass or less, further preferably 2.5% by mass or more and 7% by mass or less, further preferably 3.5% by mass or more and 6% by mass or less. The content when two or more kinds are used in combination refers to the total amount.

[0039] The water-soluble metalworking oil of the embodiment contains water. Examples of water include tap water, industrial water, ion exchange water, distilled water, sterilized purified water, etc., and hard water or soft water may be used. One type of water may be used alone, or two or more types may be used in combination.

[0040] In the water-soluble metalworking oil, from the viewpoint of processability and water dispersibility, the water content is preferably 1% by mass or more and 15% by mass or less, more preferably 2% by mass or more and 10% by mass or less, further preferably 3% by mass or more and 8% by mass or less, and still further preferably 5% by mass or more and 7% by mass or less. The content when two or more kinds are used in combination refers to the total amount.

[0041] In the water-soluble metalworking oil of the embodiment, from the viewpoint of water dispersibility, the mass ratio of the content of hydroxyl compound to the content of water (hydroxyl compound / water) is preferably 0.05 to 3.0, more preferably 0.1 to 2.0, further preferably 0.2 to 1.5, and even more preferably 0.4 to 1.0.

[0042] The water-soluble metalworking oil of the embodiment contains a base oil. As the base oil, for example, mineral oil, synthetic oil, animal and plant oils and fats, etc. can be cited, preferably mineral oil and synthetic oil. As mineral oil, spindle oil, engine oil, cylinder oil, paraffin oil, gear oil, etc. can be cited, preferably paraffin oil. As synthetic oil, synthetic oils such as hydrocarbon synthetic oil, ester synthetic oil, ether synthetic oil, etc. can be cited, preferably ester synthetic oil. As ester synthetic oil, esters of carboxylic acid (for example, carbon number 10 to 30, preferably carbon number 12 to 28, more preferably carbon number 15 to 25) and alcohol (for example, carbon number 1 to 30, preferably carbon number 1 to 25, more preferably carbon number 1 to 20) can be cited. The above-mentioned alcohol can be any one of a primary alcohol, a secondary alcohol and a tertiary alcohol, and can be any one of a monohydric alcohol, a dihydric alcohol, a trihydric alcohol and a tetrahydric alcohol. As ester synthetic oil, for example, methyl oleate, 2-ethylhexyl oleate, neopentyl glycol dioleate, trimethylolpropane trioleate, pentaerythritol tetraoleate, etc., preferably 2-ethylhexyl oleate. As animal and plant oils and fats, for example, animal oils and fats (lard, tallow, fish oil, etc.), vegetable oils and fats (rapeseed oil, soybean oil, palm oil, etc.), hydrogenated products thereof, etc. can be mentioned. The base oil can be used alone or in combination of two or more.

[0043] In the water-soluble metalworking oil, from the viewpoint of processability and water dispersibility, the content of the base oil is preferably 0.1% by mass or more and 80% by mass or less, more preferably 5% by mass or more and 77% by mass or less, further preferably 10% by mass or more and 75% by mass or less, further preferably 30% by mass or more and 70% by mass or less, further preferably 60% by mass or more and 67% by mass or less. The content when two or more kinds are used in combination refers to the total amount.

[0044] In the water-soluble metalworking oil of the embodiment, from the viewpoint of water dispersibility, the mass ratio of the content of the hydroxy compound to the content of the base oil (hydroxy compound / base oil) is preferably 0.005 to 1.0, more preferably 0.01 to 0.5, further preferably 0.02 to 0.3, and even more preferably 0.04 to 0.1.

[0045] The water-soluble metalworking oil of the embodiment contains a surfactant. The surfactant has the function of improving the liquid stability of the oil stock solution and the emulsion type metalworking fluid. Examples of the surfactant include nonionic surfactants, anionic surfactants, cationic surfactants, and amphoteric surfactants, and nonionic surfactants and anionic surfactants are preferred.

[0046] As nonionic surfactants, for example, ethers, esters, amines, amides, etc. can be mentioned. As ethers, alkyl ethers, polyoxyalkylene ethers, polyoxyalkylene alkyl ethers, etc. can be mentioned, and polyoxyalkylene alkyl ethers are preferred. As esters, glycerol fatty acid esters, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, polyoxysorbitol fatty acid esters, etc. can be mentioned, and sorbitan fatty acid esters are preferred. As amines, polyoxyalkylene alkylamines, EO adducts of organic amines, etc. can be mentioned, and EO adducts of organic amines (for example, 1 to 20 moles) can be preferably mentioned. As amides, coconut fatty acid diethanolamide, oleic acid diethanolamide, etc. can be mentioned. As nonionic surfactants, polyoxyalkylene lauryl ethers, sorbitan monooleate, and EO adducts of laurylamine are preferred.

[0047] Examples of the anionic surfactant include polyoxyalkylene alkyl ether carboxylic acids, polyoxyalkylene alkyl ether phosphoric acids, alkylbenzene sulfonic acids, α-olefin sulfonic acids, and salts thereof, and alkylbenzene sulfonates are preferred. As the anionic surfactant, sodium sulfonate is preferred.

[0048] Examples of the cationic surfactant include quaternary ammonium salts (alkyl trimethyl ammonium salts, dialkyl dimethyl ammonium salts, alkyl dimethyl benzyl ammonium salts, etc.). Examples of the amphoteric surfactant include alkyl betaines, which are betaine-based surfactants. The surfactant may be used alone or in combination of two or more.

[0049] In the water-soluble metalworking oil, from the viewpoint of liquid stability and water dispersibility, the content of the surfactant is preferably 0.1% by mass or more and 40% by mass or less, more preferably 1% by mass or more and 30% by mass or less, further preferably 5% by mass or more and 20% by mass or less, further preferably 10% by mass or more and 17% by mass or less, further preferably 12% by mass or more and 16% by mass or less. The content when two or more kinds are used in combination refers to the total amount.

[0050] In the water-soluble metalworking oil of the embodiment, from the viewpoint of water dispersibility, the mass ratio of the content of the hydroxy compound to the content of the surfactant (hydroxy compound / surfactant) is preferably 0.01 to 2.0, more preferably 0.05 to 1.5, further preferably 0.1 to 1.0, and even more preferably 0.2 to 0.4.

[0051] The water-soluble metalworking oil of the embodiment may contain various additives as needed, in addition to the above essential components, within the range not hindering the effects of the present invention. Examples of additives include rust inhibitors, metal corrosion inhibitors, fatty acids, preservatives, defoamers, and the like.

[0052] As the rust inhibitor, for example, organic amines such as alkanolamines can be cited. As organic amines, primary alkanolamines (monoethanolamine, monoisopropanolamine, 2-amino-2-methyl-1-propanol, diglycolamine, etc.), secondary alkanolamines (diethanolamine, diisopropanolamine, N-methylethanolamine, N-ethylethanolamine, N-butylethanolamine, etc.), tertiary alkanolamines (triethanolamine, triisopropanolamine, diethanol monoisopropanolamine, monoethanol diisopropanolamine, N-cyclohexyl diethanolamine, N-methyldiethanolamine, N-ethyldiethanolamine, N-butyldiethanolamine, etc.), etc., preferably tertiary alkanolamine. In water-soluble metalworking oils, from the viewpoints of rust prevention, pH adjustment, etc., the content of the rust inhibitor is, for example, 0.1% by mass or more and 20% by mass or less, preferably 0.5% by mass or more and 10% by mass or less. The content when two or more are used together refers to the total amount.

[0053] As metal corrosion inhibitors, for example, phosphoric acid esters, alkylphosphonic acids, sodium metasilicate, benzotriazole, etc. can be cited, preferably benzotriazole. The metal corrosion inhibitor can be used alone or in combination of two or more. In the water-soluble metalworking oil, the content of the metal corrosion inhibitor is, for example, 0.01 mass % or more and 5 mass % or less, preferably 0.05 mass % or more and 3 mass % or less. The content when two or more are used in combination refers to the total amount.

[0054] As fatty acids, for example, monocarboxylic acids (caproic acid, heptanoic acid, octanoic acid, 2-ethylhexanoic acid, nonanoic acid, isononanoic acid, decanoic acid, neodecanoic acid, lauric acid, myristic acid, stearic acid, oleic acid, linoleic acid, linolenic acid, ricinoleic acid, castor oil fatty acid condensate, etc.), dicarboxylic acids (adipic acid, sebacic acid, undecane dioic acid, dodecanedioic acid, etc.), etc., preferably monocarboxylic acids. Fatty acids can be used alone or in combination of two or more. In water-soluble metalworking oils, from the viewpoints of lubricity, rust resistance, corrosion resistance, etc., the content of fatty acids is, for example, 1% by mass or more and 30% by mass or less, preferably 3% by mass or more and 20% by mass or less. The content when two or more are used in combination refers to the total amount.

[0055] As the preservative, for example, organic amines can be mentioned. As the organic amine, cyclohexylamine, dicyclohexylamine, N-methyldicyclohexylamine, N,N-dimethylcyclohexylamine, dibenzylamine, 1,3-bisaminomethylcyclohexane, etc. can be mentioned, preferably dicyclohexylamine. The preservative can be used alone or in combination of two or more. In the water-soluble metalworking oil, the content of the preservative is, for example, 0.1% by mass or more and 15% by mass or less, preferably 0.5% by mass or more and 10% by mass or less. The content when two or more are used in combination refers to the total amount.

[0056] As the defoamer, for example, silicone defoamers, higher alcohol defoamers, polyether defoamers, and metal soap defoamers can be cited, preferably silicone defoamers. The defoamer can be used alone or in combination of two or more. In the water-soluble metalworking oil, the content of the defoamer is, for example, 0.01% by mass or more and 5% by mass or less, preferably 0.05% by mass or more and 3% by mass or less. The content when two or more are used in combination refers to the total amount.

[0057] The water-soluble metalworking oil of the embodiment is manufactured by mixing the above-mentioned components. The order of adding the components and the mixing method are not particularly limited. For example, the water-soluble metalworking oil can be mixed by stirring the above-mentioned components. The stirring conditions are not particularly limited, for example, a stirrer can be used to stir for about 5 minutes to 20 minutes at room temperature and a rotation speed of about 100 rpm.

[0058] The water-soluble metalworking oil according to the embodiment can be produced by post-adding (additionally adding) a hydroxy compound to the water-soluble metalworking oil containing water, a base oil, a surfactant, and the like described above.

[0059] The water-soluble metalworking oil of the embodiment can be used directly for processing a workpiece including metal, but can be particularly suitably used as a stock solution for a metalworking fluid obtained by diluting the water-soluble metalworking oil with dilution water because of its excellent water dispersibility.

[0060] [Metalworking fluid] The metalworking fluid of the embodiment contains the water-soluble metalworking oil and dilution water. Examples of the dilution water include tap water, industrial water, ion exchange water, distilled water, sterilized purified water, etc., and may be hard water or soft water. The dilution water may be used alone or in combination of two or more.

[0061] The dilution ratio when diluting the water-soluble metalworking oil with dilution water can be appropriately adjusted according to the composition of the water-soluble metalworking oil and the performance required during metal processing. The dilution ratio is not limited, and it is usually preferably diluted to 1.5 times or more and 100 times or less for use. From the viewpoint of water dispersibility and liquid stability, the dilution ratio is more preferably 5 times or more and 50 times or less, and further preferably 10 times or more and 30 times or less.

[0062] From the viewpoint of corrosion inhibition, the pH of the metalworking fluid is preferably 6.5 or more and 11.0 or less, and more preferably 7.0 or more and 10.0 or less.

[0063] The metalworking fluid of the embodiment is obtained by diluting a water-soluble metalworking oil with dilution water. The dilution method of the water-soluble metalworking oil is not particularly limited, and dilution can be performed by a known method. For example, the mixture may be mixed by stirring using a rotor or a propeller or manually, or the water-soluble metalworking oil may be added to a container containing dilution water and stirred by natural convection to dilute.

[0064] The metalworking fluid according to the embodiment has excellent dispersibility and processability, and can suppress the occurrence of stickiness in the device using the metalworking fluid, so it can be suitably used for various metal processing such as cutting, grinding, lapping, cutting, rolling, stamping, rolling, wire drawing, drawing and ironing of a workpiece including metal. Examples of the workpiece include iron-based metals and their alloys, stainless steels, aluminum, aluminum alloys, magnesium, magnesium alloys, copper, copper alloys and non-ferrous metals and their alloys.

[0065] [Metal processing method] The metalworking method according to the embodiment uses the metalworking fluid to process a workpiece containing a metal. Examples of the processing of the workpiece include cutting, grinding, lapping, cutting, rolling, stamping, rolling, wire drawing, drawing, and ironing. The metalworking fluid is supplied to the processing point in a liquid or mist state, for example. Examples of the workpiece include the metals mentioned above.

[0066] [Method for improving the dispersibility of water-soluble metalworking oil] The method for improving the dispersibility of a water-soluble metalworking oil according to an embodiment includes a step of mixing the above-mentioned hydroxyl compound, water, base oil and surfactant. In the method for improving the dispersibility of the embodiment, the water-soluble metalworking oil containing water, base oil and surfactant further contains a hydroxyl compound, so that the dispersibility of the water-soluble metalworking oil in water can be improved. Example

[0067] Hereinafter, the present invention will be described in more detail based on Examples and Comparative Examples, but the present invention is not intended to be limited to these Examples.

[0068] (Preparation of water-soluble metalworking oil) [Example 1-1] Weigh each component according to the composition shown in Table 2 so that the content of benzyl alcohol as a hydroxy compound is 4.0 parts by mass relative to 100 parts by mass of a blank containing tap water, a base oil, a surfactant and an additive. Using a stirrer (15mm×35mm, rugby type) and a stirrer ("SLOW STIRRER SW-600N-1" manufactured by Nissin Chemical Co., Ltd.), stir and mix them at 5 scales at room temperature for about 15 minutes to obtain the water-soluble metalworking oil of Example 1-1. The composition of the blank is shown in Table 1. In Example 1-1, the pH of the metalworking fluid diluted to 5 parts by mass with tap water is 9.0. The pH is measured using a pH meter ("F-52" manufactured by HORIBA).

[0069] [Examples 1-2 to 5-6, Comparative Examples 1-1 to 5-1] The mixing ratio of each component in the water-soluble metalworking oil is set as shown in Tables 2 to 6. Except for this, the metalworking oil compositions of Examples 1-2 to 5-6 and Comparative Examples 1-1 to 5-1 were prepared in the same manner as in Example 1-1. The content of the hydroxyl compound was 2.0 parts by mass in Examples 2-1 to 2-8 and Comparative Example 2-1, 3.0 parts by mass in Examples 3-1 to 3-8 and Comparative Example 3-1, 6.0 parts by mass in Examples 4-1 to 4-8 and Comparative Example 4-1, and 8.0 parts by mass in Examples 5-1 to 5-6 and Comparative Example 5-1, relative to 100 parts by mass of the blank. Comparative Example 1-4 corresponds to a blank to which no hydroxyl compound is added.

[0070] (Water dispersibility evaluation) In a flat-bottomed beaker of 500 mL capacity, 380.0 g of tap water and the above-mentioned stirring bar as dilution water were added respectively, and 20.0 g of each water-soluble metalworking oil (stock solution) was put in from a position of about 15 cm from the water surface. Then, using the above-mentioned agitator, stir and mix at 3 scales for 10 seconds, and let stand for 30 seconds after stirring stops. After standing, the appearance of the diluent was visually confirmed and evaluated according to the following benchmarks. In the case of A, B and C, it was judged that the water dispersibility was good. The evaluation results are shown in Tables 2 to 6. (Evaluation Criteria) A: No suspended matter was observed on the surface of the dilution. B: A small amount of suspended matter was observed on the surface of the dilution. C: A moderate amount of suspended matter was observed on the surface of the dilution. D: A large amount of suspended matter was observed on the surface of the dilution. E: Poor emulsification occurs.

[0071] Figure 1 This is an image for explaining the evaluation criteria of water dispersibility. Figure 1 This is an illustrative image for explaining the evaluation criteria and does not limit the actual evaluation results. The dotted line in the image indicates the area of ​​suspended matter.

[0072] The details of the components shown in Tables 1 to 6 are as follows. <Base oil> Paraffinic mineral oil 2-Ethylhexyl Oleate <Surfactant> Nonionic surfactant 1: Laurylamine EO15 molar adduct Nonionic surfactant 2: Sorbitan monooleate Nonionic surfactant 3: polyoxyalkylene lauryl ether Anionic surfactant: sodium sulfonate <Additives> Rust inhibitor: N-cyclohexyldiethanolamine Metal corrosion inhibitor: Benzotriazole Fatty acids: Oleic acid Preservative: Dicyclohexylamine Defoamer: Silicone defoamer <Hydroxy compounds> Hydroxyl compound A1: Benzyl alcohol ("Benzyl Alcohol" manufactured by LANXESS, wherein R 1 is a cyclic hydrocarbon group having 7 carbon atoms, and n is 0) Hydroxyl compound A2: benzyl alcohol EO 1 mole adduct ("BLAUNON BA-1" manufactured by Aoki Oil & Fats Industry Co., Ltd., wherein R 1 is a cyclic hydrocarbon group having 7 carbon atoms, R 2 is an alkylene group having 2 carbon atoms, and n is 1) Hydroxyl compound A3: 2-phenoxyethanol (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., wherein R 1 is a cyclic hydrocarbon group having 6 carbon atoms, R 2 is an alkylene group having 2 carbon atoms, and n is 1) Hydroxyl compound A4: 2-phenoxyisopropanol (manufactured by Tokyo Chemical Industry Co., Ltd., wherein R 1 is a cyclic hydrocarbon group having 6 carbon atoms, R 2 is an alkylene group having 3 carbon atoms, and n is 1) Hydroxyl compound A5: 2-ethylhexanol (manufactured by Tokyo Chemical Industry Co., Ltd., wherein R1 is a branched hydrocarbon group having 8 carbon atoms, and n is 0) Hydroxyl compound A6: monoethylene glycol mono-2-ethylhexyl ether ("2-ethylhexanediol" manufactured by Nippon Emulsifier Co., Ltd., where R 1 is a branched hydrocarbon group having 8 carbon atoms, R 2 is an alkylene group having 2 carbon atoms, and n is 1) Hydroxyl compound A7: diethylene glycol mono-2-ethylhexyl ether ("2-ethylhexyl diglycol" manufactured by Nippon Emulsifier Co., Ltd., where R 1 is a branched hydrocarbon group having 8 carbon atoms, R 2 is an alkylene group having 2 carbon atoms, and n is 2) Hydroxylated compound B1: polymer of hydroxyunsaturated fatty acid Hydroxyl compound B2: 1-octanol (in formula (1), R 1 is a straight-chain saturated hydrocarbon group having 8 carbon atoms, and n is 0) Hydroxyl compound B3: tetraethylene glycol mono-2-ethylhexyl ether (in formula (1), R 1 is a branched hydrocarbon group having 8 carbon atoms, R 2 is an alkylene group having 2 carbon atoms, and n is 4) Hydroxy compounds A1 to A7 are hydroxy compounds of the present invention, and hydroxy compounds B1 to B3 are comparative compounds.

[0073] [Table 1] Table 1

[0074] [Table 2]

[0075] [Table 3]

[0076] [Table 4]

[0077] [Table 5]

[0078] [Table 6]

[0079] As can be seen from Tables 2 to 6, in the Examples containing the hydroxy compound represented by formula (1), the dispersibility of the stock solution in water is good. In the Comparative Examples not containing the hydroxy compound represented by formula (1), the dispersibility of the stock solution in water is poor.

[0080] It can be seen from Examples 1-5 and Comparative Examples 1-2 that R in Formula (1) 1 In the case of a linear saturated hydrocarbon group, water dispersibility is poor. As can be seen from Examples 1-7 and Comparative Examples 1-3, water dispersibility is poor when n in formula (1) exceeds 2. It is speculated that if n of the hydroxy compound is too large, that is, the number of additions of ethylene oxide or propylene oxide is too large, the interaction on the hydrophilic side of the surfactant becomes stronger, and the effect of improving water dispersibility cannot be obtained.

[0081] It can be seen from the examples that as the content of the hydroxy compound increases, the water dispersibility tends to improve.

[0082] As described above, it was confirmed that the water-soluble metalworking oil of the present invention has excellent water dispersibility.

Claims

1. A water-soluble metalworking oil, characterized in that: Contains a hydroxy compound represented by the following general formula (1), water, a base oil and a surfactant, In formula (1), R1 is a substituted or unsubstituted branched or cyclic hydrocarbon group or a linear unsaturated hydrocarbon group having 6 to 8 carbon atoms, R2 is an alkylene group having 2 or 3 carbon atoms, and n is an integer of 0 to 2.

2. The water-soluble metalworking oil according to claim 1, wherein In the general formula (1), R1 is an aryl group.

3. The water-soluble metalworking oil according to claim 1 or 2, characterized in that: In the general formula (1), the alkylene group in R2 has 2 carbon atoms.

4. The water-soluble metalworking oil according to claim 1 or 2, characterized in that: In the general formula (1), n ​​is 1 or 2.

5. The water-soluble metalworking oil according to claim 1 or 2, characterized in that: The content of the hydroxy compound is 1.5% by mass or more and 10% by mass or less.

6. The water-soluble metalworking oil according to claim 1 or 2, characterized in that: The mass ratio of the content of the hydroxy compound to the content of the surfactant, that is, hydroxy compound / surfactant, is 0.05 or more and 1.0 or less.

7. The water-soluble metalworking oil according to claim 1 or 2, characterized in that: The surfactant is at least one selected from a nonionic surfactant and an anionic surfactant.

8. A metalworking fluid, characterized in that: The water-soluble metalworking oil according to any one of claims 1 to 7 is diluted with water.

9. A metal processing method, characterized in that: A workpiece containing metal is processed using a metalworking fluid obtained by diluting the water-soluble metalworking fluid according to any one of claims 1 to 7 with water.

10. A method for improving the dispersibility of a water-soluble metalworking oil, characterized in that: The method comprises the steps of mixing the hydroxy compound represented by the general formula (1), water, a base oil and a surfactant, In formula (1), R1 is a substituted or unsubstituted branched or cyclic hydrocarbon group or a linear unsaturated hydrocarbon group having 6 to 8 carbon atoms, R2 is an alkylene group having 2 or 3 carbon atoms, and n is an integer of 0 to 2.

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