Metal working oil composition

Abstract

To provide a new metal working oil composition with excellent metal working properties.SOLUTION: A metal working oil composition according to the present invention contains a base oil (A) and an organic acid metal salt (B), has a kinematic viscosity of 0.90 to 4.00 mm2 / s at 40°C, and has a volume resistivity of less than 2.0×10-1 TΩ m at 50°C.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a metal working oil composition and an electric discharge machining method using the metal working oil composition. [Background technology]

[0002] Lubricating oil compositions are used in a variety of applications, including lubricating sliding parts in various devices, cooling heat-generating equipment such as engines, and metal working applications to improve workability during metal working. For example, Patent Document 1 describes an electric discharge machining fluid having a kinetic viscosity of 1.0 to 3.0 mm at 40°C for machining a workpiece by accumulating discharge marks caused by electric discharge. 2 The invention discloses an electric discharge machining fluid that contains a low-viscosity oil of 0.5 to 20% by weight of a resin component and a terpene resin and / or a petroleum resin that is solid at 40°C and has a number average molecular weight of 400 to 1200. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 6-155165 Summary of the Invention [Problem to be solved by the invention]

[0004] Under these circumstances, there is a demand for novel metalworking oil compositions having excellent metal workability. [Means for solving the problem]

[0005] In one aspect of the present invention, there is provided a metal working oil composition containing a base oil and an organic acid metal salt, and having a kinematic viscosity and a volume resistivity adjusted to a predetermined range. Specifically, as one aspect of the present invention, for example, the following aspects [1] to

[15] are provided. [1] A composition comprising a base oil (A) and an organic acid metal salt (B), Kinematic viscosity at 40℃ is 0.90 to 4.00mm2 / s, Volume resistivity at 50℃ is 2.0×10 -1 is less than TΩ·m, Metalworking oil composition. [2] The metal working oil composition according to the above [1], wherein the metal working oil composition has a flash point of 70°C or higher. [3] The metal working oil composition has a kinetic viscosity of 1.00 to 3.00 mm at 40 ° C. 2 The metal working oil composition according to the above [1] or [2], wherein [4] The kinematic viscosity of the base oil (A) at 40°C is 0.90 to 4.00 mm 2 The metal working oil composition according to any one of the above [1] to [3], wherein [5] The metal working oil composition according to any one of the above [1] to [4], wherein the base oil (A) is one or more selected from mineral oils, isoparaffins, normal paraffins, and α-olefin-based synthetic oils containing α-olefins as a main component. [6] The metal working oil composition according to any one of the above [1] to [5], wherein the base oil (A) is at least one selected from normal paraffins having 10 to 30 carbon atoms and α-olefin-based synthetic oils containing, as a main component, α-olefins having 10 to 30 carbon atoms. [7] The metal working oil composition according to any one of the above [1] to [6], wherein the metal constituting the organic acid metal salt (B) is one or more selected from the group consisting of Zn, Ba, Ca, Na and K. [8] The metal working oil composition according to any one of the above [1] to [7], wherein the organic acid metal salt (B) comprises one or more selected from the group consisting of metal sulfonates, metal salicylates, metal phenates, and organic acid zinc salts. [9] The metal working oil composition according to any one of the above [1] to [7], wherein the organic acid metal salt (B) comprises one or more selected from the group consisting of metal sulfonates, metal salicylates, and metal phenates.

[10] The organic acid metal salt (B) contains an organic acid zinc salt, The metal working oil composition has a kinetic viscosity at 40°C of 1.10 to 2.70 mm 2 / s, The metal working oil composition has a volume resistivity of 8.0×10 at 50° C. -2 The metal working oil composition according to any one of the above [1] to [6], which has a viscosity of TΩ·m or less.

[11] The metal working oil composition according to any one of the above [1] to

[10] , wherein the content of the organic acid metal salt (B) in terms of metal atoms is 60 mass ppm or more based on the total amount of the metal working oil composition.

[12] The metal working oil composition according to any one of the above [1] to

[11] , wherein the combined content of the base oil (A) and the organic acid metal salt (B) is 70 mass% or more based on the total amount of the metal working oil composition.

[13] The metal working oil composition according to any one of the above [1] to

[12] , wherein the water content is less than 1.0 mass % based on the total amount of the metal working oil composition.

[14] The metal working oil composition according to any one of the above [1] to

[13] , which is a wire electric discharge machining oil composition, in which the metal working oil composition is interposed between an object to be worked on and a wire electrode, and the object to be worked on is machined by discharging between a metal of the object to be worked on and the wire electrode.

[15] A method for electric discharge machining, comprising the steps of interposing the metal working oil composition according to any one of the above [1] to

[14] between an object to be metal worked and a wire electrode, and machining the object by discharging electric current between a metal of the object to be metal worked and the wire electrode. Effect of the Invention

[0006] The metalworking oil composition according to a preferred embodiment of the present invention has excellent metal machinability, and in particular can improve the machining speed in electric discharge machining and smooth the machined surface. Therefore, the metalworking oil composition according to a preferred embodiment of the present invention is preferably applied to metal machining, and can also be suitably used in electric discharge machining (particularly wire electric discharge machining). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0007] The upper and lower limit values ​​of the numerical ranges described in this specification can be arbitrarily combined. For example, when the numerical range is described as "preferably 30 to 100, more preferably 40 to 80", the ranges "30 to 80" and "40 to 100" are also included in the numerical ranges described in this specification. In addition, when the numerical range is described as "preferably 30 or more, more preferably 40 or more, and preferably 100 or less, more preferably 80 or less", the ranges "30 to 80" and "40 to 100" are also included in the numerical ranges described in this specification. In addition, as a numerical range described in this specification, for example, "60 to 100" means a range of "60 or more (60 or more) and 100 or less (100 or less)."

[0008] [Constitution of metal processing oil composition] The metal working oil composition according to one embodiment of the present invention contains a base oil (A) (hereinafter also referred to as "component (A)") and an organic acid metal salt (B) (hereinafter also referred to as "component (B)"), and has a kinetic viscosity at 40°C of 0.90 to 4.00 mm 2 / s, and the volume resistivity at 50°C is 2.0 x 10 -1 Less than TΩ m. The metal working oil composition of one embodiment of the present invention contains the organic acid metal salt (B) together with the base oil (A), so that the work function during electrical discharge machining can be lowered and a wide machining gap can be formed. This makes it easier to discharge the machining chips and gases generated during electrical discharge machining, so that short circuits and abnormal discharges are less likely to occur, the machining speed increases, stable machining can be performed, and the machined surface of the workpiece can be machined smoothly. Therefore, the metal working oil composition of one embodiment of the present invention can be suitably used in electrical discharge machining, such as die-sinking electrical discharge machining and wire-cut electrical discharge machining. The metal working oil composition of one embodiment of the present invention having such a configuration has excellent metal workability, and in particular, can improve the machining speed in electric discharge machining and smooth the machined surface of the workpiece, thereby improving metal workability in electric discharge machining.

[0009] The kinetic viscosity at 40°C of the metal working oil composition of one embodiment of the present invention is 0.90 mm from the viewpoint of obtaining a metal working oil composition having improved metal workability, particularly from the viewpoint of obtaining a metal working oil composition capable of improving the machining speed and smoothing the machined surface when used in electric discharge machining. 2 / s or more, 0.95mm 2 / s or more, 1.00mm 2 / s or more, 1.05mm 2 / s or more, 1.10mm 2 / s or more, 1.15mm 2 / s or more, or 1.20 mm 2 / s or more, and more preferably 1.50 mm 2 / s or more, 1.60mm 2 / s or more, 1.70mm 2 / s super, 1.72mm 2 / s or more, 1.75mm 2 / s or more, 1.77mm 2 / s or more, 1.80mm 2 / s or more, 1.82mm 2 / s or more, 1.85mm 2 / s or more, or 1.87 mm 2 / s or more, and 4.00 mm 2 / s or less, 3.70mm 2 / s or less, 3.50mm 2 / s or less, 3.20mm 2 / s or less, 3.00mm 2 / s or less, 2.70mm 2 / s or less, 2.50mm 2 / s, less than 2.40mm 2 / s or less, 2.30mm 2 / s or less, 2.20mm 2 / s or less, 2.10mm 2 / s or less, or 2.00 mm 2 It is preferable to set the value to 1.97 mm / s or less. 2 / s or less, 1.95mm 2 / s or less, 1.92mm 2 / s or less, or 1.90 mm 2 / s or less may be used. In this specification, the kinematic viscosity refers to a value measured in accordance with JIS K2283:2000.

[0010] From the viewpoint of providing a metal working oil composition with improved metal workability, particularly from the viewpoint of providing a metal working oil composition capable of improving the machining speed and smoothing the machined surface when used in electric discharge machining, the volume resistivity at 50° C. of the metal working oil composition of one embodiment of the present invention is 2.0×10 -1 Less than TΩ·m, 1.0×10 -1 TΩ m or less, 8.0×10 -2 TΩ m or less, 6.0×10 -2 TΩ m or less, 4.0×10 -2 TΩ m or less, 2.0×10 -2 TΩ m or less, 1.0×10 -2 TΩ m or less, 8.0×10 -3 TΩ m or less, 6.0×10 -3 TΩ m or less, 4.0×10 -3 TΩ m or less, 2.0×10 -3 TΩ m or less, 1.0×10 -3 TΩ m or less, 8.0×10 -4 TΩ m or less, 6.0×10 -4 TΩ m or less, 4.0×10 -4 TΩ m or less, 2.0×10 -4 TΩ m or less, 1.0×10 -4 TΩ m or less, 8.0×10 -5 TΩ m or less, 6.0×10 -5 TΩ m or less, 4.0×10 -5 TΩ m or less, 2.0×10 -5 Less than TΩ·m or 1.0×10 -5 It is preferable that the resistance is less than TΩ·m, and 1.0×10 -10 TΩ m or more, 1.0×10 -9 TΩ m or more, 1.0×10 -8 TΩ·m or more, or 1.0×10 -7 It may be TΩ·m or more. In this specification, the volume resistivity means a value determined in accordance with JIS C2101 from the current value 1 minute after a voltage of 250 V / mm is applied at an oil temperature of 50°C.

[0011] In one embodiment of the metal working oil composition of the present invention, the type, kinetic viscosity, and content of component (A) and the type, base number, and content of component (B) are adjusted to adjust the kinetic viscosity and volume resistivity of the metal working oil composition to be within the above-mentioned ranges, thereby improving metal workability, and in particular, providing a metal working oil composition that can improve the machining speed when used in electric discharge machining and smooth the machined surface.

[0012] The flash point of the metal working oil composition of one embodiment of the present invention is, from the viewpoint of providing a metal working oil composition with excellent handleability, preferably 70°C or higher, more preferably 90°C or higher, more preferably 100°C or higher, even more preferably 110°C or higher, still more preferably 116°C or higher, and particularly preferably 120°C or higher. In this specification, the flash point refers to a value measured in accordance with JIS K2265-4.

[0013] The metal working oil composition of one embodiment of the present invention may contain additives other than the components (A) and (B). In the metal working oil composition of one embodiment of the present invention, from the viewpoint of providing a metal working oil composition with improved metal workability, in particular from the viewpoint of providing a metal working oil composition that can improve the machining speed and make the machined surface smoother when used in electric discharge machining, the total content of components (A) and (B) may be 70 mass% or more, 75 mass% or more, 80 mass% or more, 85 mass% or more, 90 mass% or more, 93 mass% or more, 95 mass% or more, 97 mass% or more, or 99 mass% based on the total amount (100 mass%) of the metal working oil composition. Hereinafter, each component contained in the metal working oil composition according to one embodiment of the present invention will be described.

[0014] <Component (A): Base oil> The component (A) used in one embodiment of the present invention can be one or more oils selected from mineral oils and synthetic oils. Examples of mineral oils include atmospheric residual oils obtained by atmospheric distillation of crude oils such as paraffinic crude oil, intermediate base crude oil, and naphthenic crude oil; distillate oils obtained by vacuum distillation of these atmospheric residual oils; and refined oils obtained by subjecting the distillate oils to one or more refining treatments such as solvent deasphalting, solvent extraction, hydrocracking, solvent dewaxing, catalytic dewaxing, and hydrorefining. Examples of synthetic oils include normal paraffin; isoparaffin; α-olefins; polyα-olefins such as α-olefin homopolymers or α-olefin copolymers (e.g., α-olefin copolymers having 8 to 14 carbon atoms, such as ethylene-α-olefin copolymers); isoparaffin; polyalkylene glycols; ester oils such as polyol esters and dibasic acid esters; ether oils such as polyphenyl ether; alkylbenzenes; alkylnaphthalenes; and synthetic oils (GTL) obtained by isomerizing wax produced from natural gas by the Fischer-Tropsch process or the like (GTL wax (Gas To Liquids WAX)).

[0015] Among these, from the viewpoint of obtaining a metal working oil composition with improved metal workability, in particular, from the viewpoint of obtaining a metal working oil composition that can improve the machining speed when used in electric discharge machining and can make the machined surface smoother, the component (A) used in one embodiment of the present invention is preferably one or more selected from mineral oil, isoparaffin, normal paraffin, and α-olefin synthetic oil, more preferably one or more selected from mineral oil, isoparaffin having 10 to 30 carbon atoms, normal paraffin having 10 to 30 carbon atoms, and α-olefin synthetic oil containing 10 to 30 carbon atoms α-olefin as a main component, and from the viewpoint of obtaining a metal working oil composition with low viscosity, high flash point, and excellent safety, it is further preferably one or more selected from normal paraffin having 10 to 30 carbon atoms, and α-olefin synthetic oil containing 10 to 30 carbon atoms α-olefin as a main component, and even more preferably normal paraffin having 10 to 30 carbon atoms. In this specification, the term "main component" refers to the component that is contained in the greatest amount among the components constituting component (A), and means a component that accounts for, for example, 30 mass% or more, 40 mass% or more, 50 mass% or more, 60 mass% or more, 70 mass% or more, 80 mass% or more, 90 mass% or more, or 95 mass% or more based on the total amount (100 mass%) of component (A). From the above viewpoints, the carbon number of the normal paraffin and the carbon number of the α-olefin contained as a main component in the α-olefin-based synthetic oil are each independently preferably 10 or more, more preferably 12 or more, even more preferably 13 or more, and preferably 30 or less, more preferably 20 or less, even more preferably 17 or less, and even more preferably 15 or less.

[0016] The kinetic viscosity at 40°C of the component (A) used in one embodiment of the present invention is 0.90 mm from the viewpoint of obtaining a metal processing oil composition having improved metal workability, particularly from the viewpoint of obtaining a metal processing oil composition capable of improving the processing speed and making the processed surface smoother when used in electric discharge machining. 2 / s or more, 1.00mm 2 / s or more, 1.10mm 2 / s or more, 1.20mm 2 / s super, 1.22mm 2 / s or more, 1.25mm 2 / s or more, 1.27mm 2 / s or more, 1.30mm 2 / s or more, 1.32mm 2 / s or more or 1.35 mm 2 / s or more, and 4.00 mm 2 / s or less, 3.50mm 2 / s or less, 3.20mm 2 / s or less, 3.00mm 2 / s or less, 2.70mm 2 / s or less, 2.50mm 2 / s, less than 2.20mm 2 / s or less, 2.00mm 2 / s or less, 1.90mm 2 / s or less, 1.80mm 2 / s or less, 1.70mm 2 / s or less, or 1.60 mm2 It is preferable to set the value to / s or less.

[0017] In the metal working oil composition of one embodiment of the present invention, from the viewpoint of providing a metal working oil composition with improved metal workability, in particular from the viewpoint of providing a metal working oil composition that can improve the machining speed when used in electric discharge machining and make the machined surface smoother, the content of component (A) is preferably 60 mass% or more, 65 mass% or more, 70 mass% or more, 75 mass% or more, 80 mass% or more, 85 mass% or more, 90 mass% or more, 92 mass% or more, 94 mass% or more, or 96 mass% or more based on the total amount (100 mass%) of the metal working oil composition, and is preferably 99.99 mass% or less, 99.95 mass% or less, 99.90 mass% or less, 99.80 mass% or less, 99.70 mass% or less, 99.60 mass% or less, or 99.50 mass% or less.

[0018] <Component (B): Organic acid metal salt> Component (B) used in one embodiment of the present invention includes metal salts in which the hydrogen atom of the sulfo group (-SO3H) of an organic sulfonic acid or the carboxy group (-COOH) of an organic carboxylic acid is substituted with a metal atom. The component (B) may be an organic acid metal salt having a Pauling electronegativity of 2 or less, or may be an organic acid metal salt having a Pauling electronegativity of more than 2.

[0019] From the viewpoint of providing a metal processing oil composition with improved metal machinability, in particular from the viewpoint of providing a metal processing oil composition that can improve the machining speed and smooth the machined surface when used in electric discharge machining, the metal atoms constituting component (B) are preferably one or more selected from Zn, Ba, Ca, Na, and K, and more preferably one or more selected from Zn, Ca, and Na.

[0020] Examples of the organic acid constituting component (B) include carboxylic acids and sulfonic acids. Examples of carboxylic acids include monocarboxylic acids such as caproic acid, caprylic acid, nonanoic acid, capric acid, lauric acid, myristic acid, palmitic acid, palmitoleic acid, stearic acid, oleic acid, linoleic acid, linolenic acid, arachic acid, behenic acid, melissic acid, isononanoic acid, neodecanoic acid, and isostearic acid; hydroxycarboxylic acids such as glycolic acid, hydroxyacrylic acid, oxybutyric acid, glyceric acid, malic acid, tartaric acid, citric acid, lactic acid, and salicylic acid; and polycarboxylic acids such as malonic acid, succinic acid, glutaric acid, adipic acid, maleic acid, fumaric acid, and phthalic acid.

[0021] Examples of sulfonic acids include naphthalenesulfonic acids such as 1-naphthalenesulfonic acid, 2-naphthalenesulfonic acid, 2,7-naphthalenedisulfonic acid, 1,5-naphthalenedisulfonic acid, 2,6-naphthalenedisulfonic acid, 1,3,6-naphthalenetrisulfonic acid, 3,6-dihydroxynaphthalene-2,7-disulfonic acid, 6-methyl-2-naphthalenesulfonic acid, 4-ethyl-1-naphthalenesulfonic acid, 5-isopropyl-1-naphthalenesulfonic acid, and 5-butyl-2-naphthalenesulfonic acid; benzenesulfonic acid, p-ethylbenzenesulfonic acid, 2,4,6-trimethylbenzenesulfonic acid, xylenesulfonic acid, and o-toluenesulfonic acid; Benzenesulfonic acids such as p-toluenesulfonic acid and p-cumenesulfonic acid; and azulene sulfonic acids such as 1-azulenesulfonic acid, guaiazulene sulfonic acid, 3-methyl-7-isopropyl-1-azulenesulfonic acid, 7-isopropyl-1-azulenesulfonic acid, 3-phenyl-6-isopropyl-1-azulenesulfonic acid, 1,4-dimethyl-7-isopropyl-2-azulenesulfonic acid, 1,3-azulenesulfonic acid, 4,6,8-trimethyl-1,3-azulenesulfonic acid, 1,3-bis(1,1-dimethylethyl)-5,7-azulenesulfonic acid, and 1,3-bis(1,1-dimethylethyl)-5-azulenesulfonic acid.

[0022] Among these, from the viewpoint of obtaining a metal working oil composition with improved metal workability, in particular, from the viewpoint of obtaining a metal working oil composition that can improve the machining speed when used in electric discharge machining and can make the machined surface smoother, component (B) used in one embodiment of the present invention preferably contains one or more selected from metal sulfonates, metal salicylates, metal phenates, and zinc salts of organic acids, and more preferably contains one or more selected from metal sulfonates and zinc salts of organic acids. From the above viewpoint, component (B) used in one embodiment of the present invention preferably contains one or more selected from calcium sulfonate, calcium salicylate, calcium phenate, sodium sulfonate, sodium salicylate, sodium phenate, and zinc salts of organic acids, and more preferably contains one or more selected from calcium sulfonate, sodium sulfonate, and zinc salts of organic acids.

[0023] In one embodiment of the present invention, there is mentioned a metal working oil composition containing, as component (B), one or more members selected from metal sulfonates, metal salicylates, metal phenates, and organic acid zinc salts. In one embodiment of the present invention, the metal sulfonate used as component (B) includes a compound represented by the following general formula (b-1), the metal salicylate includes a compound represented by the following general formula (b-2), and the metal phenate includes a compound represented by the following general formula (b-3). [ka]

[0024] In the above general formulae (b-1) and (b-2), M is a metal atom selected from alkali metals and alkaline earth metals, preferably sodium, calcium, magnesium, or barium, more preferably sodium or calcium. In the above general formula (b-3), M' is an alkaline earth metal, preferably calcium, magnesium or barium, and more preferably calcium. y is an integer of 0 or more, and preferably an integer of 0 to 3. In the above general formulas (b-1) to (b-3), p is the valence of M and is 1 or 2. R is a hydrogen atom or a hydrocarbon group having 1 to 18 carbon atoms. Examples of hydrocarbon groups that can be selected as R include alkyl groups having 1 to 18 carbon atoms, alkenyl groups having 1 to 18 carbon atoms, cycloalkyl groups having 3 to 18 ring carbon atoms, aryl groups having 6 to 18 ring carbon atoms, alkylaryl groups having 7 to 18 carbon atoms, and arylalkyl groups having 7 to 18 carbon atoms.

[0025] The metal sulfonates, metal salicylates, and metal phenates may be overbased metal salts of 100 mg KOH / g or more, or may be neutral metal salts of less than 100 mg KOH / g. The base number of the overbased metal salt may be 100 mgKOH / g or more, 120 mgKOH / g or more, 150 mgKOH / g or more, 170 mgKOH / g or more, or 200 mgKOH / g or more, and may be 600 mgKOH / g or less, 550 mgKOH / g or less, 500 mgKOH / g or less, 450 mgKOH / g or less, or 400 mgKOH / g or less. The base number of the neutral metal salt may be less than 100 mgKOH / g, 0 to 90 mgKOH / g, 0 to 70 mgKOH / g, 0 to 50 mgKOH / g, 0 to 40 mgKOH / g, 0 to 30 mgKOH / g, 0 to 20 mgKOH / g, or 0 to 10 mgKOH / g. In this specification, the base number refers to a value measured in accordance with "9. Potentiometric titration method (base number-perchloric acid method)" of JIS K2501 "Petroleum products and lubricants-Determination method of neutralization number".

[0026] In one embodiment of the present invention, component (B) is a metal working oil composition containing a zinc salt of an organic acid. The metalworking oil composition containing the organic acid zinc salt has a kinetic viscosity of 1.10 mm at 40°C. 2 / s or more, 1.20mm 2 / s or more, 1.30mm 2 / s or more, 1.40mm 2 / s or more, 1.50mm 2 / s or more, 1.60mm 2 / s or more, 1.70mm 2 / s or more, 1.75mm 2 / s or more, 1.77mm 2 / s or more, 1.80mm 2 / s or more, 1.82mm 2 / s or more, 1.85mm 2 / s or more, or 1.87 mm 2 / s or more, and 4.00 mm 2 / s or less, 3.50mm 2 / s or less, 3.20mm 2 / s or less, 3.00mm 2 / s or less, 2.70mm 2 / s or less, 2.50mm 2 / s, less than 2.40mm 2 / s or less, 2.30mm 2 / s or less, 2.20mm 2 / s or less, 2.10mm 2 / s or less, 2.00mm 2 / s or less, or 1.98 mm 2 It is preferable to set the value to / s or less. The volume resistivity of the metalworking oil composition containing the organic acid zinc salt at 50°C is 8.0 × 10 -2 TΩ m or less, 6.0×10 -2 TΩ m or less, 4.0×10 -2 TΩ m or less, 2.0×10 -2 TΩ·m or less, or 1.0×10 -2 It is preferable that the resistance is less than TΩ·m, and 1.0×10 -10 TΩ m or more, 1.0×10 -9 TΩ m or more, 1.0×10 -8 TΩ m or more, 1.0×10 -7 TΩ m or more, 1.0×10 -6 TΩ m or more, 1.0×10 -5 TΩ·m or more, or 1.0×10 -4 It may be TΩ·m or more.

[0027] In the metal working oil composition of one embodiment of the present invention, from the viewpoint of providing a metal working oil composition with improved metal workability, in particular from the viewpoint of providing a metal working oil composition that can improve the machining speed when used in electric discharge machining and make the machined surface smoother, the content of component (B) is preferably 0.05 mass% or more, 0.10 mass% or more, 0.15 mass% or more, 0.20 mass% or more, 0.25 mass% or more, or 0.30 mass% or more based on the total amount (100 mass%) of the metal working oil composition, and is preferably 10.0 mass% or less, 8.0 mass% or less, 7.0 mass% or less, 6.0 mass% or less, 5.0 mass% or less, 4.0 mass% or less, 3.5 mass% or less, 3.0 mass% or less, or 2.5 mass% or less.

[0028] From the above viewpoints, in the metal working oil composition of one embodiment of the present invention, the content of component (B) calculated as a metal atom is preferably 60 ppm by mass or more, 70 ppm by mass or more, 80 ppm by mass or more, 100 ppm by mass or more, 120 ppm by mass or more, 140 ppm by mass or more, 160 ppm by mass or more, 200 ppm by mass or more, 300 ppm by mass or more, 400 ppm by mass or more, 500 ppm by mass or more, 600 ppm by mass or more, or 700 ppm by mass or more based on the total amount (100 mass%) of the metal working oil composition, and is preferably 10,000 ppm by mass or less, 8,000 ppm by mass or less, 6,000 ppm by mass or less, 5,000 ppm by mass or less, 4,000 ppm by mass or less, 3,500 ppm by mass or less, 3,000 ppm by mass or less, 2,500 ppm by mass or less, 2,000 ppm by mass or less, or 1,500 ppm by mass or less. In this specification, the metal atom content means a value measured in accordance with JPI-5S-38-92.

[0029] <Other additives> The metal working oil composition of one embodiment of the present invention may further contain additives other than the above components (A) and (B) as necessary, provided that the effects of the present invention are not impaired. Examples of such other various additives include thickeners, oil-soluble resins, rust inhibitors, antifoaming agents, antioxidants, metal deactivators, and the like. These additives may be used alone or in combination of two or more kinds.

[0030] Examples of thickeners used in one embodiment of the present invention include polybutene, polyisobutylene, polyvinyl acetate, polyalkyl acrylate, ethylene-propylene copolymer, and polyalkylene glycol. In the metal working oil composition of one embodiment of the present invention, the content of the thickener may be 0.1 mass % or more, 0.5 mass % or more, or 1.0 mass % or more, based on the total amount (100 mass %) of the metal working oil composition, and may be 15 mass % or less, 5.0 mass % or less, or 2.0 mass % or less.

[0031] Examples of the oil-soluble resin used in one embodiment of the present invention include polymers of dipentene, tetraterpene, polyterpene, etc., or hydrogenated products thereof; cyclopentadiene-dicyclopentadiene copolymer petroleum resins or hydrogenated products thereof; rosin esters; coumarone resins; and coumarone-indene resins. The number average molecular weight of the oil-soluble resin used in one embodiment of the present invention may be 200 or more, 300 or more, 400 or more, or 500 or more, and may be 5,000 or less, 4,000 or less, 3,000 or less, or 2,000 or less. In the metal working oil composition of one embodiment of the present invention, the content of the oil-soluble resin may be 0.1 mass % or more, 0.5 mass % or more, or 1.0 mass % or more, based on the total amount (100 mass %) of the metal working oil composition, and may be 15 mass % or less, 5.0 mass % or less, or 2.0 mass % or less.

[0032] Examples of the rust inhibitor used in one embodiment of the present invention include alkylbenzene sulfonate, dinonylnaphthalene sulfonate, alkenyl succinate, polyhydric alcohol ester, and the like. In the metal working oil composition of one embodiment of the present invention, the content of the rust inhibitor may be 0.01 mass % or more, 0.05 mass % or more, or 0.10 mass % or more, based on the total amount (100 mass %) of the metal working oil composition, and may be 5.0 mass % or less, 3.0 mass % or less, or 2.0 mass % or less.

[0033] Examples of the defoaming agent used in one embodiment of the present invention include silicone-based defoaming agents, fluorosilicone-based defoaming agents, fluoroalkyl ether-based defoaming agents, and polyacrylate-based defoaming agents. In the metal working oil composition of one embodiment of the present invention, the content of the antifoaming agent may be 0.001 mass% or more, 0.005 mass% or more, or 0.01 mass% or more, based on the total amount (100 mass%) of the metal working oil composition, and may be 3.0 mass% or less, 1.0 mass% or less, or 0.50 mass% or less.

[0034] Examples of the antioxidant used in one embodiment of the present invention include amine-based antioxidants such as alkylated diphenylamine, phenylnaphthylamine, and alkylated phenylnaphthylamine; and phenol-based antioxidants such as 2,6-di-t-butylphenol, 4,4'-methylenebis(2,6-di-t-butylphenol), isooctyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, and n-octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate. In the metal working oil composition of one embodiment of the present invention, the content of the antioxidant may be 0.01 mass % or more, 0.05 mass % or more, or 0.10 mass % or more, based on the total amount (100 mass %) of the metal working oil composition, and may be 7.0 mass % or less, 5.0 mass % or less, or 3.0 mass % or less.

[0035] Examples of metal deactivators used in one embodiment of the present invention include benzotriazole, imidazoline, pyrimidine derivatives, thiadiazole, and the like. In the metal working oil composition of one embodiment of the present invention, the content of the metal deactivator may be 0.01 mass % or more, 0.05 mass % or more, or 0.10 mass % or more, based on the total amount (100 mass %) of the metal working oil composition, and may be 2.0 mass % or less, 1.0 mass % or less, or 0.50 mass % or less.

[0036] In the metal working oil composition of one embodiment of the present invention, the smaller the water content, the more preferable from the viewpoint of improving metal workability. In the metal working oil composition of one embodiment of the present invention, the water content is preferably less than 5.0 mass%, less than 4.0 mass%, less than 3.0 mass%, 2.5 mass% or less, less than 2.0 mass%, less than 1.5 mass%, less than 1.0 mass%, less than 0.50 mass%, or less than 0.25 mass% based on the total amount (100 mass%) of the metal working oil composition. The water content means the amount of water dissolved in the metal working oil composition.

[0037] [Method for producing metal working oil composition] The method for producing the metal working oil composition of one embodiment of the present invention is not particularly limited, and is preferably a method having a step of blending the above-mentioned component (A) with component (B) and, if necessary, other additives. The order of blending the components can be appropriately set.

[0038] [Uses of metalworking oil composition] The metal working oil composition of one embodiment of the present invention has excellent metal workability. For this reason, the metalworking oil composition of one embodiment of the present invention can be suitably used in various metalworking applications such as cutting, pressing, drawing, ironing, bending, rolling, and cold forging.

[0039] The metalworking object to be processed using the metalworking oil composition of one embodiment of the present invention is not particularly limited, and examples thereof include metal materials made of a metal selected from the group consisting of tool steel, cemented carbide, iron, titanium, aluminum, titanium alloys, alloy steels, nickel-based alloys, niobium alloys, tantalum alloys, molybdenum alloys, tungsten alloys, stainless steels, aluminum alloys, and high manganese steels.

[0040] The metalworking oil composition of one embodiment of the present invention can particularly exhibit the effects of improving the machining speed in electric discharge machining and smoothing the machined surface. Therefore, the metalworking oil composition of one embodiment of the present invention is preferably applied to metal machining, and can also be suitably used in electric discharge machining (particularly wire electric discharge machining). In other words, the metal working oil composition of one embodiment of the present invention can be suitably used as a wire electric discharge machining oil composition in which the metal working oil composition is interposed between a metal workpiece and a wire electrode, and the metal workpiece is machined by discharging between the metal of the metal workpiece and the wire electrode.

[0041] According to the above-mentioned characteristics, the present invention can also provide the following [1] and [2] as one embodiment. [1] A method for using the metal working oil composition according to one embodiment of the present invention, comprising interposing the metal working oil composition between an object to be metal worked and a wire electrode, and applying the composition to process the object to be metal worked by discharging between the metal of the object to be metal worked and the wire electrode. [2] An electric discharge machining method comprising the steps of: interposing the metal processing oil composition according to one embodiment of the present invention between an object to be processed and a wire electrode; and machining the object to be processed by generating an electric discharge between a metal of the object to be processed and the wire electrode.

[0042] The metal workpiece described in [1] and [2] above is as described above. According to the methods described in [1] and [2] above, the machining speed in electric discharge machining can be improved and the machined surface of the metal workpiece can be formed smoothly. EXAMPLES

[0043] The present invention will now be described in more detail with reference to examples, but the present invention is not limited to these examples in any way. In the following examples, the methods for measuring and calculating the following physical properties are as follows. (1)Kinematic viscosity, viscosity index Measurements and calculations were made in accordance with JIS K2283:2000. (2) Base number (perchloric acid method) Measurements were performed in accordance with "9. Potentiometric titration method (base number, perchloric acid method)" of JIS K2501 "Petroleum products and lubricants - Neutralization number test method." (3) Metal atom (Ca, Na, Zn) content Measurements were performed in accordance with JPI-5S-38-92. (4) Flash point Measurements were performed in accordance with JIS K2265-4. (5) Volume resistivity In accordance with JIS C2101, a voltage of 250 V / mm was applied at an oil temperature of 50°C, and calculations were made from the current value one minute after application.

[0044] Examples 1 to 5, Comparative Examples 1 to 6 Metal working oil compositions were prepared by adding and mixing various components of the types shown in Tables 1 and 2 in the amounts shown in the tables. The amounts of organic acid metal salts are calculated as active ingredients. Details of each component used in the preparation of the metal working oil compositions are as follows.

[0045] <Base oil (A)> "α-Olefin (1)": α-olefin synthetic oil containing α-olefin with 14 carbon atoms as the main component, kinematic viscosity at 40°C = 1.8 mm 2 / s. "α-Olefin (2)": α-olefin synthetic oil containing α-olefin with 10 carbon atoms as the main component, kinematic viscosity at 40°C = 0.87 mm 2 / s. "α-Olefin (3)": α-olefin synthetic oil containing α-olefin with 12 carbon atoms as the main component, kinematic viscosity at 40°C = 1.2 mm 2 / s. "α-Olefin (4)": α-olefin synthetic oil containing α-olefin with 16 carbon atoms as the main component, kinematic viscosity at 40°C = 2.6 mm 2 / s. "PAO": Poly α-olefin synthetic oil, 40℃ kinematic viscosity = 5.1mm 2 / s. <Organic acid metal salt (B)> "Ca Sulfonate": Calcium sulfonate with a base number of 495 mg KOH / g. "Na sulfonate": Sodium sulfonate with a base value of 3.85 mg KOH / g. "Zinc salt": Zinc salt of fatty acid with a base number of 0.25 mg KOH / g, zinc atom content = 10.6% by mass.

[0046] The prepared metalworking oil compositions were measured for their kinematic viscosity at 40°C, the content of metal atoms (Ca, Na, Zn) derived from organic acid metal salts, the flash point, and the volume resistivity, and were also subjected to the following metalworking property evaluation tests. The test results are shown in Tables 1 and 2.

[0047] (1) Evaluation of metal workability based on work speed ratio The prepared metalworking oil composition was used to perform wire electric discharge machining of steel under the following machining conditions, and the machining speed was measured. The machining speed was calculated using the following formula. ·Processing speed (mm 3 / min)=L×T×W / t (In the above formula, L is the machining distance (mm), T is the thickness of the workpiece (mm), W is the average groove width (mm), and t is the machining time (powder).) <Workpiece> SKD11 (thickness 2.0mm) <Processing conditions> · Machining machine: MAKINO UPV-3 (product name, manufactured by Makino Milling Machine Co., Ltd.) Wire diameter: 0.20mm Wire material: Brass ·Maximum cutting speed: 10mm / min Wire speed: 20m / min In addition, the "processing speed ratio relative to the processing speed in Comparative Example 1" (hereinafter also referred to as "processing speed ratio") was calculated from the following formula. It can be said that the larger the processing speed ratio, the more excellent the metal processing ability of the metal processing oil composition. Machining speed ratio = [Machining speed when using the target metalworking oil composition (mm 3 / min)] / [Processing speed when the metalworking oil composition of Comparative Example 2 was used (mm 3 / min)]

[0048] (2) Evaluation of metal workability based on the Rz ratio of machined surface The maximum height roughness Rz of the cut surface of the workpiece after measuring the machining speed in (1) above (hereinafter also referred to as "machined surface roughness Rz") was measured using a contact type surface roughness measuring instrument Surfcom1400D / G (product name, manufactured by Tokyo Seimitsu Co., Ltd.) in accordance with JIS B0633:2001. Then, the "ratio of the processed surface roughness Rz to the processed surface roughness Rz of Comparative Example 1" (hereinafter also referred to as the "processed surface roughness Rz ratio") was calculated from the following formula. It can be said that the smaller the value of the processed surface roughness Rz ratio, the more excellent the metal workability of the metal processing oil composition. Machined surface roughness Rz ratio=[machined surface roughness Rz (μm) when the target metalworking oil composition is used] / [machined surface roughness Rz (μm) when the metalworking oil composition of Comparative Example 2 is used]

[0049] [Table 1]

[0050] [Table 2]

[0051] As shown in Table 1, the metal working oil compositions prepared in Examples 1 to 5 contained an organic acid metal salt, and had their 40°C kinematic viscosity and volume resistivity adjusted to a predetermined range, and therefore had a higher machining speed ratio and lower machined surface roughness Rz, resulting in excellent metal workability, compared to the metal working oil compositions of Comparative Examples 1 to 6. In Comparative Example 1, the flash point of the metal working oil composition was too low, so measurements of the volume resistivity and evaluation tests of metal workability were not performed.

Claims

1. It contains a base oil (A) and an organic acid metal salt (B), The kinematic viscosity at 40°C is 0.90 to 4.00 mm². ２ / s, The volume resistivity at 50°C is 2.0 × 10⁻⁶ －１ It is less than TΩ·m. Metalworking oil composition.

2. The metalworking oil composition according to claim 1, wherein the flash point of the metalworking oil composition is 70°C or higher.

3. The kinematic viscosity of the metalworking oil composition at 40°C is 1.00 to 3.00 mm. ２ A metalworking oil composition according to claim 1 or 2, wherein the ratio is / s.

4. The kinematic viscosity of base oil (A) at 40°C is 0.90 to 4.00 mm². ２ A metalworking oil composition according to claim 1 or 2, wherein the ratio is / s.

5. The metalworking oil composition according to claim 1 or 2, wherein the base oil (A) is one or more selected from mineral oil, isoparaffin, normal paraffin, and α-olefin-based synthetic oil containing α-olefin as the main component.

6. The metalworking oil composition according to claim 1 or 2, wherein the base oil (A) is one or more selected from normal paraffins having 10 to 30 carbon atoms and α-olefin-based synthetic oils containing α-olefins having 10 to 30 carbon atoms as main components.

7. The metalworking oil composition according to claim 1 or 2, wherein the metal constituting the organic acid metal salt (B) is one or more selected from Zn, Ba, Ca, Na, and K.

8. The metalworking oil composition according to claim 1 or 2, wherein the organic acid metal salt (B) comprises one or more selected from metal sulfonates, metal salicylates, metal phenates, and organic acid zinc salts.

9. The metalworking oil composition according to claim 1 or 2, wherein the organic acid metal salt (B) comprises one or more selected from metal sulfonates, metal salicylates, and metal phenates.

10. The organic acid metal salt (B) contains an organic acid zinc salt, The kinematic viscosity of the metalworking oil composition at 40°C is 1.10 to 2.70 mm. ２ / s, The volume resistivity of the metalworking oil composition at 50°C is 8.0 × 10⁻⁶. －２ A metalworking oil composition according to claim 1 or 2, wherein the TΩ·m is ≤.

11. The metalworking oil composition according to claim 1 or 2, wherein the content of the organic acid metal salt (B) in terms of metal atoms is 60 ppm by mass or more on a total basis of the metalworking oil composition.

12. The metalworking oil composition according to claim 1 or 2, wherein the total content of the base oil (A) and the organic acid metal salt (B) is 70% by mass or more based on the total amount of the metalworking oil composition.

13. The metalworking oil composition according to claim 1 or 2, wherein the water content is less than 1.0% by mass on a total basis of the metalworking oil composition.

14. The metalworking oil composition according to claim 1 or 2, wherein the metalworking oil composition is a wire electrical discharge machining oil composition used to process a metalworking object by interposing the metalworking oil composition between the workpiece and a wire electrode and discharging an electrical discharge between the metal of the workpiece and the wire electrode.

15. A method for electrical discharge machining, comprising the step of interposing the metalworking oil composition according to claim 1 or 2 between a workpiece and a wire electrode, and machining the workpiece by discharging an electrical discharge between the metal of the workpiece and the wire electrode.