Water-soluble metalworking oil agent

Abstract

To provide a metalworking oil fluid that can be a water-soluble metalworking oil of which performance can be maintained for a long period of time.SOLUTION: A water-soluble metalworking oil agent containing two or more amine compounds (A) having an evaporation rate of 20% or less when heated at 50°C for 48 hours, as calculated by the following formula (i), and fatty acids (B), wherein the content of amine compounds (X), which do not fall under the component (A), is less than 5.0 pts.mass per 100 pts.mass of the total amount of component (A). Formula (i): Evaporation rate (%)=([Mass of amine compounds before heating] - [Mass of amine compounds after heating for 48 hours]) / [Mass of amine compounds before heating]×100.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a water-soluble metalworking oil, a metalworking fluid obtained by mixing the water-soluble metalworking oil with dilution water, and a metalworking method for applying the metalworking fluid to a workpiece made of metal. [Background technology]

[0002] 2. Description of the Related Art In the field of metalworking such as cutting and grinding, metalworking fluids are used for the purposes of improving the workability of workpieces and suppressing wear of processing tools. Metalworking fluids include oil-based fluids, which are mainly composed of oils such as mineral oils, synthetic oils, and animal and vegetable oils, and water-soluble fluids, which are made water-soluble by blending oils with compounds having surface activity. In recent years, water-soluble metalworking fluids have come to be used for safety reasons, such as a low risk of fire.

[0003] For example, Patent Document 1 discloses an invention relating to a concentrated metalworking fluid that contains 60 to 90% by weight of a base oil selected from the group consisting of water-soluble polyalkylene glycols, methoxypolyethylene glycols, and combinations of two or more of them, 5 to 20% by weight of a glycol ether, 0.01 to 5% by weight of an oil-soluble polyalkylene glycol, and 0.2 to 6% by weight of an additive. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2010 / 113594 Summary of the Invention [Problem to be solved by the invention]

[0005] However, water-soluble metalworking fluids such as those described in Patent Document 1 are used repeatedly during metalworking, but the deterioration of performance over long-term use is a problem. Therefore, there is a demand for water-soluble metalworking oils that can be used to prepare metalworking oils that can maintain their performance over a long period of time. [Means for solving the problem]

[0006] The present invention provides a water-soluble metalworking oil agent that contains two or more amine compounds having a specific volatility rate of a predetermined value or less and fatty acids, and in which the content of amine compounds having a specific volatility rate exceeding the predetermined value is limited. Specifically, the present invention provides, for example, the following aspects [1] to

[13] . [1] The present invention comprises two or more amine compounds (A) each having a volatility of 20% or less when heated at 50° C. for 48 hours, as calculated from the following formula (i), and a fatty acid (B), A water-soluble metalworking oil, comprising an amine compound (X) not corresponding to component (A) in an amount of less than 5.0 parts by mass per 100 parts by mass of the total amount of component (A). Formula (i): Volatility rate (%) = ([mass of amine compound before heating] - [mass of amine compound after heating for 48 hours]) / [mass of amine compound before heating] x 100 [2] The water-soluble metalworking oil according to the above-mentioned [1], wherein the content of component (A) is more than 5.0 mass% based on the total amount of the water-soluble metalworking oil. [3] The water-soluble metalworking oil according to the above [1] or [2], wherein the component (A) contains at least two kinds of amine compounds (A1) having a volatility rate of 10% or less. [4] The water-soluble metalworking oil according to any one of the above [1] to [3], wherein the combined content of the polyalkylene glycol (Y1) having a weight-average molecular weight of 12,000 or less and the water-insoluble compound having a polyoxyalkylene group (Y2) is less than 70 mass% based on the total amount of the water-soluble metalworking oil. [5] The water-soluble metalworking oil according to any one of the above [1] to [4], wherein the content of the polyalkylene glycol (Y1) having a weight-average molecular weight of 12,000 or less is less than 15.0 mass% based on the total amount of the water-soluble metalworking oil. [6] The water-soluble metalworking oil according to any one of the above [1] to [5], wherein the content of the water-insoluble compound (Y2) having a polyoxyalkylene group is less than 15.0 mass% based on the total amount of the water-soluble metalworking oil. [7] The water-soluble metalworking oil according to any one of the above [1] to [6], wherein the content of component (B) is 5.0 mass % or more based on the total amount of the water-soluble metalworking oil. [8] The water-soluble metalworking oil according to any one of the above [1] to [7], wherein the ratio of the base number derived from the component (A) to the acid number derived from the component (B) [(A) / (B)] is 0.50 to 10.0. [9] The water-soluble metalworking oil according to any one of the above [1] to [8], further comprising a nonionic surfactant (C).

[10] The water-soluble metalworking oil according to any one of the above [1] to [9], further comprising a base oil (D).

[11] The water-soluble metalworking oil according to any one of the above [1] to

[10] , further comprising water (E).

[12] A metalworking fluid obtained by mixing the water-soluble metalworking oil agent according to any one of the above [1] to

[11] with dilution water.

[13] A metalworking method comprising applying the metalworking fluid described in

[12] above to a workpiece made of metal. Effect of the Invention

[0007] The water-soluble metalworking oil agent according to a preferred embodiment of the present invention can be diluted with dilution water to prepare a metalworking oil having excellent thermal stability and corrosion resistance and capable of maintaining its performance for a long period of time. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] 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)."

[0009] In this specification, the term "metalworking oil" refers to a stock solution of a metalworking fluid before it is diluted with dilution water to produce a metalworking fluid, and is in a suitable form for transport or storage before use in metalworking. Also, the term "metalworking fluid" refers to a stock solution of a metalworking oil diluted with dilution water, and is in a suitable form for use in metalworking. "Metalworking oils" and "metalworking fluids" can also be distinguished, for example, by the water content as follows: "Metalworking oil": The water content is between 0 and 400 parts by mass per 100 parts by mass of the total amount of ingredients other than water. "Metalworking fluid": The water content is more than 400 parts by mass per 100 parts by mass of the total amount of ingredients other than water.

[0010] [Composition of water-soluble metalworking oil] The water-soluble metalworking oil of the present invention contains two or more amine compounds (A) (hereinafter also referred to as "component (A)") having a volatility of 20% or less, as calculated from formula (i), and fatty acids (B) (hereinafter also referred to as "component (B)"), and is prepared so that the content of amine compound (X) (hereinafter also referred to as "component (X)") not corresponding to component (A) is less than 5.0 parts by mass per 100 parts by mass of the total amount of component (A). In this specification, "water-soluble" means a component that dissolves in an amount of 20 g or more in 100 g of water at 25°C and has a total light transmittance of 90% or more after adding 20 g of the target substance to 100 g of water at 25°C.

[0011] The present inventors have found that the deterioration in performance that occurs when metalworking oils are used for a long period of time is caused by the fact that amine salts are formed in the metalworking oil from amine compounds and fatty acids, and the amines in the amine salts are volatilized by the heat generated during metalworking. The water-soluble metalworking oil of one embodiment of the present invention was completed based on this finding, and contains an amine compound (A) having a volatility rate of 20% or less calculated from formula (i) together with fatty acids (B), and limits the content of an amine compound (X) that does not fall under component (A) and that may cause a decrease in performance. As a result, it is believed that the amine of the amine salt formed in the metalworking oil prepared from the water-soluble metalworking oil of one embodiment of the present invention is less likely to volatilize even due to heat generated during metalworking, and performance can be maintained for a long period of time.

[0012] The water-soluble metalworking oil agent of one embodiment of the present invention may further contain a nonionic surfactant (C) (hereinafter, also referred to as "component (C)"). The water-soluble metal working oil of one embodiment of the present invention may further contain a base oil (D) (hereinafter, also referred to as "component (D)"). The water-soluble metalworking oil of one embodiment of the present invention may further contain water (E) (hereinafter, also referred to as "component (E)"). By adjusting the content of water (E), it is possible to prepare an emulsion-type oil classified as type A1 or a soluble-type oil classified as type A2 as specified in JIS K2241:2017. The water-soluble metalworking oil agent of one embodiment of the present invention preferably contains two or more selected from component (C), component (D), and component (E), and more preferably contains all of component (C), component (D), and component (E).

[0013] The water-soluble metalworking oil agent according to one embodiment of the present invention may contain components other than the components (A) to (E) to the extent that the effects of the present invention are not impaired.

[0014] In the water-soluble metal working oil of one embodiment of the present invention, the total content of components (A) and (B) is, based on the total amount (100 mass%) of the water-soluble metal working oil, preferably 10 mass% or more, more preferably 15 mass% or more, even more preferably 20 mass% or more, still more preferably 25 mass% or more, and particularly preferably 28 mass% or more, and may be 100 mass% or less, 90 mass% or less, 80 mass% or less, 70 mass% or less, 65 mass% or less, 60 mass% or less, 55 mass% or less, 50 mass% or less, or 48 mass% or less.

[0015] In the water-soluble metal working oil of one embodiment of the present invention, the total content of the components (A) to (E) is, based on the total amount (100 mass%) of the water-soluble metal working oil, preferably 40 mass% or more, more preferably 50 mass% or more, more preferably 60 mass% or more, even more preferably 70 mass% or more, still more preferably 80 mass% or more, particularly preferably 90 mass% or more, and may be 100 mass% or less, 99 mass% or less, 98 mass% or less, or 97 mass% or less. Hereinafter, each component contained in the water-soluble metalworking oil agent according to one embodiment of the present invention will be described.

[0016] <Component (A): Amine compound> A water-soluble metal-working oil agent according to one embodiment of the present invention contains two or more amine compounds (A) having a volatilization rate of 20% or less when heated at 50° C. for 48 hours, as calculated from the following formula (i): Formula (i): Volatility rate (%) = ([mass of amine compound before heating] - [mass of amine compound after heating for 48 hours]) / [mass of amine compound before heating] x 100 In this specification, the volatility rate refers to a value measured based on the method described in the Examples section below.

[0017] The water-soluble metal working oil of one embodiment of the present invention contains component (A), so that when the water-soluble metal working oil is diluted to prepare a metal working oil, the amine of the amine salt formed from components (A) and (B) in the metal working oil is less likely to volatilize even due to heat generated during metal working, making it possible to provide a metal working oil whose performance is maintained for a long period of time.

[0018] In the water-soluble metal working oil of one embodiment of the present invention, from the viewpoint of obtaining a water-soluble metal working oil capable of preparing a metal working oil that has excellent thermal stability and putrefaction resistance and can maintain its performance over a long period of time, the content of component (A) is preferably more than 5.0 mass%, 7.0 mass% or more, 9.0 mass% or more, 10.0 mass% or more, 11.0 mass% or more, 12.0 mass% or more, 14.0 mass% or more, 16.0 mass% or more, 18.0 mass% or more, 20.0 mass% or more, 22.0 mass% or more, 24.0 mass% or more, or 26.0 mass% or more based on the total amount (100 mass%) of the water-soluble metal working oil, and may also be 60.0 mass% or less, 55.0 mass% or less, 50.0 mass% or less, 45.0 mass% or less, 40.0 mass% or less, 37.0 mass% or less, 35.0 mass% or less, 32.0 mass% or less, or 30.0 mass% or less.

[0019] In one aspect of the water-soluble metal working oil of the present invention, from the viewpoint of providing a water-soluble metal working oil capable of preparing a metal working oil that is excellent in thermal stability and putrefaction resistance and can maintain its performance for a long period of time, the content of component (A) is more than 5.0 mass%, 7.0 mass% or more, 9.0 mass% or more, 10.0 mass% or more, 11.0 mass% or more, 12.0 mass% or more, 13.0 mass% or more, 15.0 mass% or more, based on the total amount (100 mass%) of the water-soluble metal working oil excluding water. It is preferable that the content be 0.0% by mass or more, 17.0% by mass or more, 20.0% by mass or more, 22.0% by mass or more, 24.0% by mass or more, 26.0% by mass or more, 28.0% by mass or more, or 30.0% by mass or more, and it may also be 70.0% by mass or less, 65.0% by mass or less, 60.0% by mass or less, 55.0% by mass or less, 50.0% by mass or less, 45.0% by mass or less, 40.0% by mass or less, 37.0% by mass or less, or 35.0% by mass or less.

[0020] From the viewpoint of obtaining a water-soluble metal working oil agent that is excellent in thermal stability and putrefaction resistance and can prepare a metal working oil that can maintain its performance for a long period of time, the volatility of component (A) used in one embodiment of the present invention is preferably 20% or less, 18% or less, 16% or less, 14% or less, 12% or less, 11% or less, 10% or less, 9.0% or less, 8.0% or less, 7.0% or less, 6.0% or less, 5.0% or less, 4.0% or less, 3.0% or less, 2.0% or less, 1.0% or less, or 0.50% or less.

[0021] Component (A) used in one embodiment of the present invention is composed of two or more amine compounds having a volatility rate of 20% or less, from the viewpoint of preparing a water-soluble metal working oil agent that is excellent in thermal stability and corrosion resistance and can maintain its performance over a long period of time, and preferably contains at least two amine compounds (A1) having a volatility rate of 10% or less. The volatility rate of the amine compound (A1) is 10% or less, and from the above viewpoints, it is more preferably 9.0% or less, 8.0% or less, 7.0% or less, 6.0% or less, 5.0% or less, 4.0% or less, 3.0% or less, 2.0% or less, 1.0% or less, or 0.50% or less.

[0022] In one aspect of the water-soluble metal working oil of the present invention, from the viewpoint of providing a water-soluble metal working oil that is excellent in thermal stability and putrefaction resistance and can prepare a metal working oil that can maintain its performance over a long period of time, the content of component (A1) is preferably 20 mass% or more, 25 mass% or more, 30 mass% or more, 35 mass% or more, 40 mass% or more, 45 mass% or more, 50 mass% or more, 55 mass% or more, 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, 95 mass% or more, 98 mass% or more, or 100 mass% based on the total amount (100 mass%) of component (A) contained in the water-soluble metal working oil.

[0023] Component (A) used in one embodiment of the present invention is not particularly limited as long as the volatility rate is 20% or less, and may be, for example, any of the above-mentioned monoamines having one amino nitrogen atom in one molecule, diamines having two amino nitrogen atoms in one molecule, and polyamines having three or more amino nitrogen atoms in one molecule. However, from the viewpoint of keeping the volatilization rate at or below a predetermined value, the component (A) used in one embodiment of the present invention is preferably a monoamine.

[0024] The monoamine used as component (A) in one embodiment of the present invention may be any of primary amines, secondary amines, and tertiary amines. From the viewpoint of keeping the volatility rate at or below a predetermined value, the primary amine is preferably a primary amine compound represented by the following general formula (a-1), the secondary amine is preferably a secondary amine compound represented by the following general formula (a-2), and the tertiary amine is preferably a tertiary amine compound represented by the following general formula (a-3).

[0025] [ka]

[0026] In the general formula (a-1), p1 and p2 each independently represent an integer of 0 to 10, preferably an integer of 1 to 6, more preferably an integer of 1 to 4, even more preferably an integer of 2 to 3, and still more preferably 2. x1 is 0 or 1.

[0027] The primary amine compound represented by the general formula (a-1) is preferably 2-(2-aminoethoxy)ethanol.

[0028] In the general formula (a-2), R 11 ~R 14 each independently represents a hydrogen atom, a hydroxyl group, a straight-chain or branched-chain alkyl group which may be substituted with a hydroxyl group, or a phenyl group. R 11 ~R 14 The alkyl group that can be selected as the alkyl group preferably has 1 to 12 carbon atoms, more preferably 1 to 10 carbon atoms, even more preferably 1 to 6 carbon atoms, and even more preferably 1 to 3 carbon atoms. However, R 11 and R 13 It is preferable that at least one of R is a hydrogen atom and the other is a group other than a hydrogen atom. 12 and R 14 It is preferable that at least one of the groups is a hydrogen atom and the other is a group other than a hydrogen atom. X 1 and X 2 are each independently an oxygen atom, an oxyethylene group, or an oxypropylene group. p3 and p4 are each independently an integer of 0 to 10, preferably an integer of 0 to 6, and more preferably an integer of 0 to 3.

[0029] The secondary amine compound represented by the general formula (a-2) is preferably diisopropanolamine or dibenzylamine, and more preferably dibenzylamine.

[0030] In the general formula (a-3), R 21 ~R 24 each independently represents a hydrogen atom, a hydroxyl group, a straight-chain or branched-chain alkyl group which may be substituted with a hydroxyl group, or a phenyl group. R 21 ~R 24The alkyl group that can be selected as the alkyl group preferably has 1 to 12 carbon atoms, more preferably 1 to 10 carbon atoms, even more preferably 1 to 6 carbon atoms, and even more preferably 1 to 3 carbon atoms. However, R 21 and R 23 It is preferable that at least one of R is a hydrogen atom and the other is a group other than a hydrogen atom. 22 and R 24 It is preferable that at least one of the groups is a hydrogen atom and the other is a group other than a hydrogen atom. X 3 and X 4 are each independently an oxygen atom, an oxyethylene group, or an oxypropylene group. p3 and p4 are each independently an integer of 0 to 10, preferably an integer of 0 to 6, and more preferably an integer of 0 to 3. R 31 is a straight-chain or branched-chain alkyl group which may be substituted with a hydroxyl group, a phenyl group, or a cyclohexyl group. R 31 The alkyl group that can be selected as the alkyl group preferably has 1 to 12 carbon atoms, more preferably 1 to 10 carbon atoms, even more preferably 1 to 6 carbon atoms, and even more preferably 1 to 3 carbon atoms.

[0031] The tertiary amine compound represented by the general formula (a-3) is preferably N-methyldiethanolamine, triethanolamine, triisopropanolamine, cyclohexyldiethanolamine, or a polyoxyalkylene alkylamine, and more preferably contains at least cyclohexyldiethanolamine or a polyoxyalkylene alkylamine.

[0032] R in the general formulae (a-2) to (a-3) 11 ~R 14 , R 21 ~R 24 and R 31Examples of the alkyl group that can be selected as the aryl group include a methyl group, an ethyl group, a propyl group (n-propyl group, i-propyl group), a butyl group (n-butyl group, i-butyl group, s-butyl group, t-butyl group), a pentyl group (n-pentyl group, i-pentyl group, neopentyl group), a hexyl group, a heptyl group, an octyl group, a 2-ethylhexyl group, a nonyl group, a decyl group, an undecyl group, and a dodecyl group. The alkyl group may be a straight chain alkyl group or a branched chain alkyl group.

[0033] The component (A) used in one embodiment of the present invention consists of a combination of two or more types, and specific examples thereof include the following combinations. (i) A combination of at least one primary amine and at least one secondary amine. (ii) A combination of at least one primary amine and at least one tertiary amine. (iii) A combination of at least one secondary amine and at least one tertiary amine. (iv) A combination of at least one primary amine, at least one secondary amine, and at least one tertiary amine. (v) A combination of at least two primary amines. (vi) A combination of at least two secondary amines. (vii) A combination of at least two tertiary amines. Among the above combinations, from the viewpoint of obtaining a water-soluble metal working oil agent capable of preparing a metal working oil having excellent thermal stability and corrosion resistance and capable of maintaining performance over a long period of time, the combination of (i), (ii), (iii), (iv), (vi) or (vii) is preferred, the combination of (i), (ii), (iv), (vi) or (vii) is more preferred, the combination of (i), (iv) or (vii) is even more preferred, and the combination of (iv) or (vii) is even more preferred.

[0034] From the viewpoint of obtaining a water-soluble metal working oil agent that is excellent in thermal stability and putrefaction resistance and can prepare a metal working oil that can maintain its performance for a long period of time, the base number (amine number) of component (A) used in one embodiment of the present invention is preferably 560 mgKOH / g or less, 550 mgKOH / g or less, or 540 mgKOH / g or less, and more preferably more than 100 mgKOH / g, 150 mgKOH / g or more, or 170 mgKOH / g or more.

[0035] When a primary amine compound is used as component (A), from the viewpoint of obtaining a water-soluble metalworking oil agent capable of preparing a metalworking oil having excellent thermal stability and corrosion resistance and capable of maintaining its performance over a long period of time, the base number (amine value) of the primary amine compound is preferably 560 mgKOH / g or less, 550 mgKOH / g or less, or 540 mgKOH / g or less, and is also preferably more than 100 mgKOH / g, 150 mgKOH / g or more, 170 mgKOH / g or more, 200 mgKOH / g or more, 250 mgKOH / g or more, 300 mgKOH / g or more, 350 mgKOH / g or more, 400 mgKOH / g or more, 450 mgKOH / g or less, or 500 mgKOH / g or more.

[0036] When a secondary amine compound is used as component (A), from the viewpoint of obtaining a water-soluble metalworking oil capable of preparing a metalworking oil having excellent thermal stability and corrosion resistance and capable of maintaining its performance over a long period of time, the base number (amine value) of the secondary amine compound is preferably 570 mgKOH / g or less, 550 mgKOH / g or less, 530 mgKOH / g or less, 500 mgKOH / g or less, 470 mgKOH / g or less, 450 mgKOH / g or less, 430 mgKOH / g or less, 400 mgKOH / g or less, 370 mgKOH / g or less, 350 mgKOH / g or less, 330 mgKOH / g or less, or 300 mgKOH / g or less, and is preferably more than 100 mgKOH / g, 150 mgKOH / g or more, 170 mgKOH / g or more, 200 mgKOH / g or more, or 250 mgKOH / g or more.

[0037] When a tertiary amine compound is used as component (A), from the viewpoint of obtaining a water-soluble metalworking oil agent capable of preparing a metalworking oil having excellent thermal stability and corrosion resistance and capable of maintaining its performance over a long period of time, the base number (amine value) of the tertiary amine compound is preferably 570 mgKOH / g or less, 550 mgKOH / g or less, 530 mgKOH / g or less, 500 mgKOH / g or less, 470 mgKOH / g or less, 450 mgKOH / g or less, 430 mgKOH / g or less, 400 mgKOH / g or less, 370 mgKOH / g or less, 350 mgKOH / g or less, 330 mgKOH / g or less, or 300 mgKOH / g or less, and is preferably more than 100 mgKOH / g, 150 mgKOH / g or more, or 170 mgKOH / g or more.

[0038] In this specification, the base number (amine number) means a value measured in accordance with JIS K2501:2003 (hydrochloric acid method).

[0039] <Component (X): Amine compounds not falling under component (A)> In one embodiment of the water-soluble metal working oil of the present invention, the content of the amine compound (X) not corresponding to component (A) is limited to less than 5.0 parts by mass per 100 parts by mass of the total amount of component (A), from the viewpoint of providing a water-soluble metal working oil that is excellent in thermal stability and corrosion resistance and can prepare a metal working oil that can maintain its performance over a long period of time. From the above viewpoint, in the water-soluble metal lubricant of one embodiment of the present invention, the content of component (X) is preferably less than 4.5 parts by mass, less than 4.0 parts by mass, less than 3.0 parts by mass, less than 2.0 parts by mass, less than 1.0 parts by mass, less than 0.50 parts by mass, less than 0.10 parts by mass, less than 0.01 parts by mass, less than 0.001 parts by mass, or less than 0.0001 parts by mass, relative to 100 parts by mass of the total amount of component (A).

[0040] From the above viewpoints, the content of component (X) in the water-soluble metalworking oil of one embodiment of the present invention is preferably less than 1.0 mass%, less than 0.10 mass%, less than 500 ppm by mass, less than 100 ppm by mass, less than 50 ppm by mass, less than 10 ppm by mass, less than 5.0 ppm by mass, or less than 1.0 ppm by mass, based on the total amount (100 mass%) of the water-soluble metalworking oil.

[0041] <Component (B): Fatty acids> The water-soluble metal-working oil agent according to one embodiment of the present invention contains fatty acids (B). By containing component (B), a water-soluble metalworking oil agent can be obtained that can serve as a metalworking fluid having improved performance in various areas, such as emulsion stability, rust prevention, and workability. In the water-soluble metal-working oil agent according to one embodiment of the present invention, the component (B) may be used alone or in combination of two or more kinds.

[0042] In the water-soluble metal working oil of one embodiment of the present invention, the content of component (B) is preferably 2.0 mass% or more, 3.0 mass% or more, 5.0 mass% or more, 7.0 mass% or more, 10.0 mass% or more, 12.0 mass% or more, 14.0 mass% or more, or 16.0 mass% or more based on the total amount (100 mass%) of the water-soluble metal working oil, and is preferably 60 mass% or less, 50 mass% or less, 40 mass% or less, 35 mass% or less, 30 mass% or less, 25 mass% or less, or 20 mass% or less.

[0043] In the water-soluble metal working oil of one embodiment of the present invention, the content of component (B) is preferably 2.0 mass% or more, 3.0 mass% or more, 5.0 mass% or more, 7.0 mass% or more, 10.0 mass% or more, 12.0 mass% or more, 14.0 mass% or more, 16.0 mass% or more, or 18.0 mass% based on the total amount (100 mass%) of the water-soluble metal working oil excluding water, and is preferably 60 mass% or less, 50 mass% or less, 40 mass% or less, 35 mass% or less, 30 mass% or less, 25 mass% or less, or 22 mass% or less.

[0044] Examples of the component (B) used in one embodiment of the present invention include fatty acids, hydroxy fatty acids, aliphatic dicarboxylic acids, dimer acids of fatty acids, and polymerized fatty acids of hydroxy unsaturated fatty acids.

[0045] Examples of the fatty acid include saturated aliphatic monocarboxylic acids such as octanoic acid, 2-ethylhexanoic acid, decanoic acid, neodecanoic acid, undecanoic acid, dodecanoic acid, tridecanoic acid, pentadecanoic acid, heptadecanoic acid, nonadecanoic acid, myristic acid, palmitic acid, stearic acid, arachic acid, behenic acid, and isostearic acid, and unsaturated aliphatic monocarboxylic acids such as octenoic acid, nonenoic acid, decenoic acid, undecenoic acid, oleic acid, elaidic acid, erucic acid, nervonic acid, linoleic acid, γ-linolenic acid, arachidonic acid, α-linolenic acid, stearidonic acid, eicosapentaenoic acid, and docosahexaenoic acid. Furthermore, mixtures of unsaturated fatty acids such as tall oil fatty acid, soybean oil fatty acid, palm oil fatty acid, linseed oil fatty acid, rice bran oil fatty acid, cottonseed oil fatty acid, etc. may also be used. The fatty acid preferably has 8 to 30 carbon atoms, more preferably 10 to 25 carbon atoms, and even more preferably 10 to 20 carbon atoms.

[0046] Examples of the hydroxy fatty acid include hydroxylauric acid, hydroxymyristic acid, hydroxypalmitic acid, hydroxystearic acid, hydroxyarachic acid, hydroxybehenic acid, and hydroxyoctadecenoic acid. The hydroxy fatty acid preferably has 8 to 30 carbon atoms, more preferably 10 to 25 carbon atoms, and even more preferably 10 to 20 carbon atoms.

[0047] Examples of the aliphatic dicarboxylic acid include sebacic acid, dodecanedioic acid, dodecyl succinic acid, lauryl succinic acid, stearyl succinic acid, and isostearyl succinic acid. The aliphatic dicarboxylic acid preferably has 8 to 30 carbon atoms, more preferably 10 to 25 carbon atoms, and further preferably 10 to 20 carbon atoms.

[0048] Examples of the hydroxy unsaturated fatty acid constituting the polymerized fatty acid of the hydroxy unsaturated fatty acid include ricinoleic acid (12-hydroxyoctadec-9-enoic acid), etc. Also, a fatty acid mixture containing ricinoleic acid such as castor oil may be used. Examples of the polymerized fatty acid of the hydroxy unsaturated fatty acid include a condensed fatty acid which is a dehydration polycondensation product of a hydroxy unsaturated fatty acid, and a condensed fatty acid obtained by dehydration condensation of an alcoholic hydroxyl group of a condensed fatty acid which is a dehydration polycondensation product of a hydroxy unsaturated fatty acid with a monocarboxylic acid.

[0049] From the viewpoint of obtaining a water-soluble metalworking oil that can become a metalworking fluid with improved workability, the acid value of component (B) is usually 0 mgKOH / g or more, and is preferably 5 mgKOH / g or more, 10 mgKOH / g or more, 15 mgKOH / g or more, or 20 mgKOH / g or more, and may be 100 mgKOH / g or less, 90 mgKOH / g or less, 80 mgKOH / g or less, 70 mgKOH / g or less, 60 mgKOH / g or less, 50 mgKOH / g or less, 40 mgKOH / g or less, or 30 mgKOH / g or less. The hydroxyl value of component (B) is preferably 80 mgKOH / g or less, 60 mgKOH / g or less, 40 mgKOH / g or less, 20 mgKOH / g or less, 10 mgKOH / g or less, or 5 mgKOH / g or less, and may be 0 mgKOH / g or more, 0.1 mgKOH / g or more, or 0.5 mgKOH / g or more. From the above viewpoints, the ratio of the acid value to the hydroxyl value of component (B) [acid value / hydroxyl value] is preferably 1.5 or more, 2.0 or more, 2.5 or more, 5.0 or more, 10 or more, or 15 or more; and is preferably 50 or less, 40 or less, 35 or less, 30 or less, or 25 or less. It is preferable that the saponification value of component (B) is 10 mgKOH / g or more, 20 mgKOH / g or more, 40 mgKOH / g or more, 60 mgKOH / g or more, 100 mgKOH / g or more, 150 mgKOH / g or more, 180 mgKOH / g or more, 190 mgKOH / g or more, or 195 mgKOH / g or more, and it is preferable that it is 300 mgKOH / g or less, 250 mgKOH / g or less, 220 mgKOH / g or less, 210 mgKOH / g or less, or 205 mgKOH / g or less. In this specification, the acid value means a value measured in accordance with JIS K2501:2003 (indicator photometric titration method), the hydroxyl value means a value measured in accordance with JIS K0070:1992, and the saponification value means a value measured based on JIS K2503:1996.

[0050] In one aspect of the water-soluble metal working oil of the present invention, from the viewpoint of providing a water-soluble metal working oil that is excellent in thermal stability and corrosion resistance and can prepare a metal working oil that can maintain its performance over a long period of time, the ratio of the base number (amine number) derived from component (A) to the acid number derived from component (B) [(A) / (B)] is 0.50 or more, 0.60 or more, 0.70 or more, 0.80 or more, 0.90 or more, 1.00 or more, 1.10 or more, 1.20 or more, 1.30 or more, It is preferable that the refractive index is 1.00 or more, 1.40 or more, 1.50 or more, 1.60 or more, 1.70 or more, 1.80 or more, 1.90 or more, 2.00 or more, 2.20 or more, 2.40 or more, 2.50 or more, 2.60 or more, 2.80 or more, or 3.00 or more, and it is preferable that the refractive index is 10.0 or less, 9.0 or less, 8.0 or less, 7.0 or less, 6.5 or less, 6.0 or less, 5.5 or less, 5.0 or less, 4.5 or less, 4.0 or less, or 3.5 or less.

[0051] <Nonionic surfactants (C)> The water-soluble metalworking oil of one embodiment of the present invention preferably further contains a nonionic surfactant (C). By containing the component (C), the water-soluble metalworking oil can be made into a metalworking fluid having improved emulsion stability and workability. In the water-soluble metal-working oil agent according to one embodiment of the present invention, the component (C) may be used alone or in combination of two or more kinds.

[0052] From the above viewpoints, in the water-soluble metal working oil of one embodiment of the present invention, the content of component (C) is preferably 0.10 mass% or more, 0.30 mass% or more, 0.50 mass% or more, 0.70 mass% or more, 1.00 mass% or more, 1.20 mass% or more, 1.50 mass% or more, 1.70 mass% or more, 2.00 mass% or more, 2.20 mass% or more, 2.50 mass% or more, or 2.70 mass% or more based on the total amount (100 mass%) of the water-soluble metal working oil, and is preferably 15.0 mass% or less, 12.0 mass% or less, 10.0 mass% or less, 8.0 mass% or less, 6.0 mass% or less, 5.0 mass% or less, 4.5 mass% or less, or 4.0 mass% or less.

[0053] From the above viewpoints, in the water-soluble metalworking oil of one embodiment of the present invention, the content of component (C) is, based on the total amount (100 mass%) of the water-soluble metalworking oil excluding water, preferably 0.20 mass% or more, 0.40 mass% or more, 0.60 mass% or more, 0.80 mass% or more, 1.00 mass% or more, 1.20 mass% or more, 1.50 mass% or more, 1.70 mass% or more, 2.00 mass% or more, 2.20 mass% or more, 2.50 mass% or more, 2.70 mass% or more, or 3.00 mass% or more, and is preferably 15.0 mass% or less, 12.0 mass% or less, 10.0 mass% or less, 8.0 mass% or less, 6.0 mass% or less, 5.0 mass% or less, 4.5 mass% or less, or 4.0 mass% or less.

[0054] From the viewpoint of obtaining a water-soluble metalworking oil that can become a metalworking fluid having improved emulsion stability and workability, the HLB of component (C) used in one embodiment of the present invention is preferably 6.0 or more, more preferably 7.0 or more, even more preferably 8.0 or more, still more preferably 9.0 or more, particularly preferably 10.0 or more, and is 18.0 or less, preferably 17.0 or less, more preferably 16.0 or less, even more preferably 15.0 or less, and still more preferably 14.5 or less. In this specification, HLB refers to a value calculated by the Griffin method.

[0055] Examples of component (C) used in one embodiment of the present invention include alkylene glycols, polyoxyalkylene alkyl ethers, polyoxyalkylene aryl ethers, polyoxyalkylene alkylamines (cocoamine alkylene oxide adducts), alkylphenol alkylene oxide adducts, higher alcohol alkylene oxide adducts, polyoxyalkylene fatty acid esters, fatty acid esters of glycerin and pentaerythritol, fatty acid esters of sucrose, fatty acid esters of polyoxyalkylene adducts of polyhydric alcohols, alkyl polyglycosides, and fatty acid alkanolamides.

[0056] Among these, from the viewpoint of obtaining a water-soluble metalworking oil agent that can become a metalworking fluid having improved emulsion stability and processability, it is preferable that component (C) used in one embodiment of the present invention contains one or more selected from polyoxyalkylene alkyl ethers and polyoxyalkylene alkyl amines. The total content of polyoxyalkylene alkyl ether and polyoxyalkylene alkyl amine is preferably 50 to 100 mass%, more preferably 70 to 100 mass%, even more preferably 80 to 100 mass%, still more preferably 90 to 100 mass%, and particularly preferably 95 to 100 mass%, based on the total amount (100 mass%) of component (C) contained in the water-soluble metalworking oil.

[0057] <Component (D): Base oil> The water-soluble metalworking oil of the present invention preferably further contains a base oil (D). By containing component (D), the water-soluble metalworking oil can be a metalworking fluid with improved workability. The component (D) used in one embodiment of the present invention may be used alone or in combination of two or more kinds.

[0058] In the water-soluble metal working oil of one embodiment of the present invention, the content of component (D) based on the total amount (100 mass%) of the water-soluble metal working oil may be 0.01 mass% or more, 0.1 mass% or more, 1.0 mass% or more, 3.0 mass% or more, 5.0 mass% or more, 10.0 mass% or more, 20.0 mass% or more, 25.0 mass% or more, 30.0 mass% or more, 35.0 mass% or more, or 40.0 mass% or more, or may be 80 mass% or less, 70 mass% or less, 65 mass% or less, 60 mass% or less, 55 mass% or less, 50 mass% or less, 45 mass% or less, 40 mass% or less, or 35 mass% or less.

[0059] In addition, when the oil is an emulsion type classified as Type A1 as specified in JIS K2241:2017, the content of component (A) may be 10 mass% or more, 15 mass% or more, 20 mass% or more, 30 mass% or more, 40 mass% or more, 45 mass% or more, or 50 mass% or more based on the total amount of the oil (100 mass%).

[0060] When the oil is a soluble type classified as Type A2 as specified in JIS K2241:2017, the content of component (A) may be 60 mass% or less, 50 mass% or less, 40 mass% or less, 30 mass% or less, 25 mass% or less, 20 mass% or less, 15 mass% or less, or 10 mass% or less based on the total amount (100 mass%) of the oil.

[0061] In addition, in the water-soluble metal working oil of one embodiment of the present invention, the content of component (D) based on the total amount (100 mass%) of the water-soluble metal working oil excluding water may be 0.01 mass% or more, 0.1 mass% or more, 1.0 mass% or more, 3.0 mass% or more, 5.0 mass% or more, 10.0 mass% or more, 20.0 mass% or more, 25.0 mass% or more, 30.0 mass% or more, 35.0 mass% or more, or 40.0 mass% or more, and may be 80 mass% or less, 70 mass% or less, 65 mass% or less, 60 mass% or less, 55 mass% or less, 50 mass% or less, 45 mass% or less, 40 mass% or less, or 35 mass% or less.

[0062] In addition, when the oil is an emulsion type classified as Type A1 as specified in JIS K2241:2017, the content of component (D) may be 10 mass% or more, 15 mass% or more, 20 mass% or more, 30 mass% or more, 40 mass% or more, 45 mass% or more, or 50 mass% or more based on the total amount (100 mass%) of the oil excluding water.

[0063] Furthermore, in the case of a soluble oil agent classified as Type A2 as specified in JIS K2241:2017, the content of component (D) may be 60 mass% or less, 50 mass% or less, 40 mass% or less, 30 mass% or less, 25 mass% or less, or 20 mass% or less based on the total amount (100 mass%) of the oil agent excluding water.

[0064] The component (D) used in one embodiment of the present invention includes 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.

[0065] Examples of synthetic oils include poly-α-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); isoparaffins; ester-based oils such as polyol esters, dibasic acid esters, and phosphate esters; ether-based 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)).

[0066] The kinetic viscosity at 40° C. of the component (D) used in one embodiment of the present invention is preferably 2.0 to 150 mm from the viewpoint of forming a water-soluble metalworking oil capable of forming a metalworking fluid having excellent workability. 2 / s, more preferably 3.0 to 120 mm 2 / s, more preferably 5.0 to 100 mm 2 / s, and even more preferably 6.0 to 90 mm 2 / s, particularly preferably 7.0 to 80 mm 2 / s.

[0067] <Component (E): Water> The water-soluble metalworking oil of one embodiment of the present invention may further contain water (E). By making the water-soluble metalworking oil contain water, it is possible to impart flame retardancy to the water-soluble metalworking oil, making it non-hazardous, and improving the handling properties during storage. The water as component (E) used in one embodiment of the present invention is not particularly limited, and may be, for example, any of distilled water, ion-exchanged water, tap water, industrial water, and the like.

[0068] In the water-soluble metal-working oil of one embodiment of the present invention, the content of component (E) is 400 parts by mass or less, preferably 1 to 350 parts by mass, more preferably 2 to 300 parts by mass, even more preferably 3 to 250 parts by mass, and still more preferably 5 to 200 parts by mass, per 100 parts by mass of the total amount of components other than water in the water-soluble metal-working oil. In addition, when the water-soluble metalworking oil is an emulsion-type oil classified as Type A1 as specified in JIS K2241:2017, the content of component (E) may be 150 parts by mass or less, 100 parts by mass or less, 70 parts by mass or less, 50 parts by mass or less, 40 parts by mass or less, 30 parts by mass or less, 20 parts by mass or less, or 15 parts by mass or less, per 100 parts by mass of the total amount of components other than water in the water-soluble metalworking oil, and the lower limit is as described above. Furthermore, in the case of a soluble oil classified as Type A2 as specified in JIS K2241:2017, the content of component (E) may be 10 parts by mass or more, 30 parts by mass or more, 50 parts by mass or more, 60 parts by mass or more, 70 parts by mass or more, 80 parts by mass or more, 90 parts by mass or more, or 100 parts by mass or more, per 100 parts by mass of the total amount of components other than water in the water-soluble metalworking oil, and the upper limit is as described above.

[0069] In the water-soluble metal working oil of one embodiment of the present invention, the content of component (E) is preferably 1 to 99 mass%, more preferably 2 to 90 mass%, even more preferably 3 to 85 mass%, and still more preferably 5 to 80 mass%, based on the total amount (100 mass%) of the water-soluble metal working oil. In addition, when the water-soluble metalworking oil is an emulsion-type oil classified as Type A1 as specified in JIS K2241:2017, the content of component (E) may be 70 mass% or less, 60 mass% or less, 50 mass% or less, 40 mass% or less, 30 mass% or less, 25 mass% or less, 20 mass% or less, or 15 mass% or less based on the total amount (100 mass%) of the water-soluble metalworking oil, and the lower limit is as described above. Furthermore, in the case of a soluble oil classified as Type A2 as specified in JIS K2241:2017, the content of component (E) may be 10 mass% or more, 15 mass% or more, 20 mass% or more, 25 parts by mass or more, 30 mass% or more, 35 mass% or more, 40 mass% or more, 45 mass% or more, or 50 mass% or more based on the total amount (100 mass%) of the water-soluble metalworking oil, and the upper limit is as described above.

[0070] <Polyalkylene glycol (Y1), water-insoluble compound having a polyoxyalkylene group (Y2)> In the water-soluble metal working oil of one embodiment of the present invention, the total content of the polyalkylene glycol (Y1) (hereinafter also referred to as "component (Y1)") having a weight average molecular weight of 12,000 or less and the water-insoluble compound (Y2) (hereinafter also referred to as "component (Y2)") having a polyoxyalkylene group, based on the total amount (100 mass%) of the water-soluble metal working oil, may be less than 70 mass%, less than 60 mass%, less than 50 mass%, less than 40 mass%, less than 30 mass%, less than 20 mass%, less than 15 mass%, less than 10 mass%, or less than 5.0 mass%.

[0071] In the water-soluble metal working oil of one embodiment of the present invention, the content of component (Y1) may be less than 45.0 mass%, less than 40.0 mass%, less than 35.0 mass%, less than 30.0 mass%, less than 25.0 mass%, less than 20.0 mass%, less than 15.0 mass%, less than 10.0 mass%, or less than 5.0 mass% based on the total amount (100 mass%) of the water-soluble metal working oil.

[0072] In the water-soluble metal working oil of one embodiment of the present invention, the content of component (Y2) may be less than 40.0 mass%, less than 30.0 mass%, less than 20.0 mass%, less than 15.0 mass%, less than 10.0 mass%, less than 5.0 mass%, less than 1.0 mass%, less than 0.1 mass%, less than 0.01 mass%, less than 0.001 mass%, less than 0.0001 mass%, or less than 0.00001 mass%, based on the total amount (100 mass%) of the water-soluble metal working oil.

[0073] <Other additives> The water-soluble metal working oil agent according to one embodiment of the present invention may further contain various other additives other than the above components (A) to (E) as necessary, provided that the effects of the present invention are not impaired. Examples of such other various additives include anionic surfactants, cationic surfactants, petroleum sulfonates, extreme pressure agents, metal deactivators, emulsifying aids, antibacterial agents, antifoaming agents, antioxidants, oiliness agents, and the like. These various additives may be used alone or in combination of two or more kinds.

[0074] In the water-soluble metal working oil of one embodiment of the present invention, the content of each of these various additives is appropriately set depending on the type and function of each component, but is preferably 0.01 to 40 mass%, more preferably 0.07 to 30 mass%, and even more preferably 0.1 to 20 mass%, based on the total amount (100 mass%) of the water-soluble metal working oil.

[0075] In the water-soluble metal working oil agent of one embodiment of the present invention, the content of each of these various additives is appropriately set depending on the type and function of each component, but may be 0.001 mass% or more, 0.01 mass% or more, 0.1 mass% or more, 1.0 mass% or more, or 3.0 mass% or more based on the total amount (100 mass%) of the water-soluble metal working oil agent, and may be 20 mass% or less, 15 mass% or less, 10 mass% or less, 5.0 mass% or less, or 1.0 mass% or less.

[0076] In addition, the water-soluble metalworking oil of one embodiment of the present invention may be substantially free of a specific additive among these various additives. Note that the term "substantially free" excludes cases in which the target additive is added with a specific intention, and does not exclude cases in which the additive is unavoidably contained. When a specific additive is substantially not contained, the content of the additive may be less than 0.1 mass%, less than 0.01 mass%, less than 0.001 mass%, less than 0.0001 mass%, or less than 0.00001 mass%, based on the total amount (100 mass%) of the water-soluble metalworking oil.

[0077] Examples of the anionic surfactant include polyoxyethylene alkyl ether carboxylic acid, polyoxyethylene alkyl ether phosphoric acid, alkylbenzene sulfonic acid, α-olefin sulfonic acid, and salts thereof. The acid value of the anionic surfactant is preferably 20 to 250 mgKOH / g, more preferably 30 to 200 mgKOH / g, even more preferably 40 to 190 mgKOH / g, and even more preferably 50 to 180 mgKOH / g. Examples of the cationic surfactant include alkyltrimethylammonium salts, dialkyldimethylammonium salts, and alkyldimethylbenzylammonium salts.

[0078] Examples of the petroleum sulfonates include calcium sulfonate, sodium sulfonate, and magnesium sulfonate.

[0079] Examples of extreme pressure agents include chlorine-based extreme pressure agents such as chlorinated paraffin, chlorinated fatty acid, and chlorinated fatty oil; phosphorus-based extreme pressure agents such as phosphate esters, phosphites, thiophosphate esters, and salts thereof, phosphines, and tricresyl phosphate; and sulfur-based extreme pressure agents such as sulfurized olefins, sulfurized lard, alkyl polysulfides, and sulfurized fatty acids.

[0080] Metal deactivators include, for example, benzotriazoles, imidazolines, pyrimidine derivatives, and thiadiazoles.

[0081] Examples of the emulsifying aid include unsaturated fatty acid esters such as methyl oleate, ethyl oleate, and propyl oleate; aromatic alcohols such as 2-phenoxyethanol and 2-phenylethyl alcohol; and the like.

[0082] Examples of antibacterial agents include isothiazolinone compounds, triazine compounds, alkylbenzimidazole compounds, and metal pyrithione salts.

[0083] Examples of the defoaming agent include silicone-based defoaming agents, fluorosilicone-based defoaming agents, polyacrylates, and the like.

[0084] Examples of the antioxidant 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.

[0085] Examples of oily agents include alcohols such as lauryl alcohol, myristyl alcohol, palmityl alcohol, stearyl alcohol, and oleyl alcohol.

[0086] <Method of manufacturing water-soluble metalworking oil> The method for producing the water-soluble metalworking oil agent according to one embodiment of the present invention is not particularly limited, and is preferably a method having a step of blending the above-mentioned components (A) and (B), and, if necessary, components (C) to (E) and various other additives. The order of blending the components can be appropriately set.

[0087] [Form of metalworking fluid] The metalworking fluid of one embodiment of the present invention is prepared by mixing the metalworking oil according to the above-mentioned one embodiment of the present invention as a stock solution with dilution water. The dilution water may be, for example, any of distilled water, ion-exchanged water, tap water, industrial water, and the like.

[0088] The amount of dilution water to be blended when preparing a metalworking fluid is more than 400 parts by mass per 100 parts by mass of the total amount of the components other than water in the water-soluble metalworking oil, but it is preferable to appropriately adjust this amount to a desired dilution concentration. The dilution concentration of the metalworking fluid of one embodiment of the present invention is preferably 1 to 50% by volume, more preferably 3 to 40% by volume, and further preferably 5 to 20% by volume. In this specification, the above-mentioned "dilution concentration of the metalworking fluid" means a value calculated from the following formula. "Dilution concentration of metalworking fluid (volume %)" = [Volume of metalworking fluid before dilution] / [[Volume of metalworking fluid before dilution] + [Volume of dilution water]] x 100

[0089] [Uses of metalworking fluids and metalworking methods] The metalworking fluid of a preferred embodiment of the present invention has superior thermal stability and corrosion resistance compared to conventional metalworking fluids, and can maintain its performance for a long period of time. Therefore, the metalworking fluid of a preferred embodiment of the present invention can be used repeatedly in metalworking applications, thereby reducing consumption of oil agents.

[0090] The workpiece to be machined using the metalworking fluid of one embodiment of the present invention is not particularly limited, but is particularly suitable for workpieces made of metals selected from the group consisting of 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. Among these, the metalworking fluid is particularly suitable for workpieces having a member containing at least iron or aluminum.

[0091] Therefore, the present invention can also provide the following [1] and [2]. [1] A method of using the metalworking fluid according to one embodiment of the present invention described above for machining a workpiece made of metal. [2] A metalworking method, comprising applying the metalworking fluid according to one embodiment of the present invention to a workpiece made of metal.

[0092] The workpieces described in [1] and [2] above are as described above, but for example, a workpiece having a member containing at least iron or aluminum is preferable.

[0093] In the above items (1) and (2), examples of the processing of the workpiece include cutting, grinding, punching, polishing, drawing, drawing, rolling, and the like. In the above-mentioned method of use [1] and the above-mentioned method of metalworking [2], the metalworking fluid is prepared by mixing the water-soluble metalworking oil of one embodiment of the present invention with dilution water, supplying the mixture to the workpiece, and contacting the workpiece. The metalworking fluid lubricates the area between the workpiece and the tool. It is also used to remove chips, prevent rust on the workpiece, and cool the tool and the workpiece. EXAMPLES

[0094] 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) Volatility of amine compounds 20 g of the amine compound to be measured was weighed on an electronic balance into a glass petri dish (manufactured by Kenis Co., Ltd.) with a diameter of 70 mm, and placed without a lid in a precision thermostatic oven (fine oven) with an explosion vent (manufactured by Yamato Scientific Co., Ltd., model "DF412S") The vent was then fully opened, and the temperature was raised from 25°C to 50°C over 30 minutes, and the mixture was heated at 50°C for 48 hours. The mass of the amine compound after heating was measured on an electronic balance and calculated from the following formula. Volatility rate (%) = ([Mass of amine compound before heating (20 g)] - [Mass of amine compound after heating for 48 hours (g)]) / [Mass of amine compound before heating (20 g)] x 100 (2) Base number (hydrochloric acid method) Measurements were performed in accordance with JIS K2501:2003 (hydrochloric acid method). (3) Acid value (indicator photometric titration method) Measurements were performed in accordance with JIS K2501:2003 (indicator photometric titration method). (4)HLB Calculations were based on the Griffin method. (5) Kinematic viscosity, viscosity index Measurements and calculations were made in accordance with JIS K2283:2000.

[0095] Examples 1 to 19, Comparative Examples 1 to 20 Each water-soluble metalworking oil was prepared by adding and mixing various components of the types shown in Tables 1 to 4 in the amounts shown in each table. The contents of the polyalkylene glycol (Y1) having a weight average molecular weight (Mw) of 12,000 or less and the water-insoluble compound having a polyoxyalkylene group (Y2) contained in the prepared water-soluble metalworking oil were both "0 mass%". The details of each component used in preparing the water-soluble metalworking oil are as follows:

[0096] <Component (A)> - "2-(2-aminoethoxy)ethanol": Primary amine, volatility rate = 4.00%, total base number = 534 mg KOH / g. "Diisopropanolamine": Secondary amine, volatility rate = 11.00%, total base number = 365 mg KOH / g. "Dibenzylamine": Secondary amine, volatility rate = 2.00%, total base number = 279 mg KOH / g. "N-Methyldiethanolamine": Tertiary amine, volatility rate = 7.00%, total base number = 434 mg KOH / g. - "Triisopropanolamine": Tertiary amine, volatility rate = 8.00%, total base number = 249 mg KOH / g. - "Cyclohexyldiethanolamine": Tertiary amine, volatility rate = 0.10%, total base number = 297 mg KOH / g. "POE alkylamine (EO:2)": Tertiary amine, polyoxyethylene (2EO) alkylamine, volatility rate = 0.10%, total base number = 200mgKOH / g.

[0097] <Component (X)> "Monoisopropanolamine": Primary amine, volatility rate = 100.00%, total base number = 747 mg KOH / g. - "2-Amino-2-methyl-1-propanol": Primary amine, volatility rate = 100.00%, total base number = 565 mg KOH / g. "N-Methylethanolamine": Primary amine, volatility rate = 100.00%, total base number = 747 mg KOH / g. "Dicyclohexylamine": Primary amine, volatility rate = 61.00%, total base number = 309 mg KOH / g. "N-Methyldicyclohexylamine": Primary amine, volatility rate = 28.00%, total base number = 287 mg KOH / g.

[0098] <Ingredient (B)> "Fatty acid mixture": a fatty acid mixture mainly containing dodecanedioic acid, neodecanoic acid, tall oil fatty acid, and ricinoleic acid polymerized fatty acid (castor oil polymerized fatty acid), acid value = 22.0 mg KOH / g, hydroxyl value = 1.1 mg KOH / g. <Component (C)> - "Polyoxyalkylene alkyl ether": Nonionic surfactant, HLB=12.7. <Ingredient (D)> "Paraffinic mineral oil": 40℃ kinematic viscosity = 7.117mm2 / s, and a paraffinic mineral oil with a viscosity index of 109. · "PAO": 40℃ kinematic viscosity = 31.0mm 2 / s, viscosity index = 132. Poly-alphaolefin synthetic oil. "Ester-based synthetic oil": 40℃ kinematic viscosity = 49.45mm 2 / s, viscosity index = 189 trimethylolpropane trioleate. <Ingredient (E)> Water: Ion-exchanged water <Other additives> Benzotriazole: metal deactivator "Oleyl alcohol": Emulsifying agent 1,2-Benzisothiazolin-3-one: Antibacterial agent "Silicone-based defoaming agent"

[0099] The prepared water-soluble metalworking fluids were used to carry out the following evaluations, and the results are shown in Tables 1 to 4.

[0100] (1) Hume color test Approximately 0.1 mL of water-soluble metalworking oil was dropped onto a cold-rolled steel plate (SPCC-SD) heated to 80°C, and a 50 mL glass bottle was placed so that the opening was in contact with the cold-rolled steel plate to cover the dropped oil, and left to stand in this state for one minute to capture the fume components of the oil. After that, an aqueous solution of thymol blue (which is alkaline and turns from yellow to blue) was added to the fume components captured in the glass bottle to check for coloration, and the volatility of the alkaline components was evaluated according to the following criteria. A: No color change was observed, and no volatilization of alkaline components including amine compounds was confirmed. F: The color turned blue, and the evaporation of alkaline components including amine compounds was confirmed.

[0101] (2) Thermal stability test The test fluid was a metalworking fluid with a fluid concentration of 5% by volume, prepared by diluting a water-soluble metalworking fluid with water. 20 g of the test liquid was dropped into a petri dish with a diameter of 70 mm, and the weight of the petri dish was measured. The petri dish was then heated at 50°C for 24 hours (1 day) without a lid, and ion-exchanged water was added to replace the weight of the test liquid lost by heating. The pH of the test liquid was then measured using a pH meter (product name "HM-25R", manufactured by DKK-TOA Corporation). The pH value is shown in Tables 1 to 4 as "pH after 24 hours of heating". In addition, the above-mentioned "heating at 50°C for 24 hours" and "addition of ion-exchanged water to compensate for the mass loss" were repeated for 7 days (heating time 168 hours), after which the pH of the test solution was measured. This pH value is shown in Tables 1 to 4 as "pH after heating for 168 hours." If the test liquid separated before the heating time reached 168 hours and the pH could no longer be measured, it was deemed "measurement impossible" and the liquid was determined to be water-soluble metalworking oil with poor thermal stability, and no further operations were performed. The smaller the difference between the "pH after 24 hours of heating" and the "pH after 168 hours of heating," the more thermally stable the water-soluble metalworking oil is.

[0102] (3) Rot resistance test [Preparation of test solution] A metalworking fluid with an oil concentration of 3% by volume, prepared by diluting a water-soluble metalworking oil with water, was used as the "test fluid before thermal degradation." Additionally, 100 mL of the above pre-thermal degradation test liquid was heated at 50°C for 48 hours, and ion-exchanged water was added to replace the weight loss to create the metalworking liquid "post-thermal degradation test liquid." If the test liquid separated after 48 hours of heating and the "post-thermal degradation test liquid" could not be prepared, it was deemed "measurement not possible" and the following corrosion resistance test using the "post-thermal degradation test liquid" was not performed. [Resistant to decay test] To 100 mL of the above "test liquid before thermal degradation" or "test liquid after thermal degradation", 5 mL of putrefactive liquid A and 0.5 mL of putrefactive liquid B described below were added, and the mixture was shaken at 30°C and 150 rpm for one week (7 days). After one week of incubation, the viable bacteria count in the test solution was measured, and the number of bacteria was 10 6 The test was terminated if the bacterial count was 106 If the number of bacteria was less than 10 / mL, 2.5 mL of putrefactive fluid A and 0.25 mL of putrefactive fluid B were added, and the mixture was shaken for another week (7 days) to measure the number of viable bacteria. 6 The number of weeks at which the number of cells / mL or more is shown in Tables 1 to 4. The longer the number of weeks, the more excellent the putrefaction resistance of the water-soluble metalworking oil.

[0103] The spoilage test conditions and the method for measuring the viable cell count are as follows. (Decomposition test conditions) Culture conditions: 3 g of FC200 dry cutting chips were added and cultured at 30°C with shaking at 150 rpm. Decayed fluid A: A solution that was activated by adding SCD medium "Daigo" (product name, manufactured by Nippon Pharmaceutical Co., Ltd.) to a decayed and deteriorated emulsion-type cutting fluid and aerating it for 72 hours. Decayed fluid B: A solution that was activated by adding potato dextrose agar medium "Daigo" (product name, manufactured by Nippon Pharmaceutical Co., Ltd.) to a decayed and deteriorated emulsion-type cutting fluid and aerating it for 72 hours. (Method for measuring viable cell count) The number of bacteria in 1 mL was measured using a total bacteria count measuring device, "Sanai Biochecker TTC" (product name, manufactured by Sanai Oburi Co., Ltd.).

[0104] [Table 1]

[0105] [Table 2]

[0106] [Table 3]

[0107] [Table 4]

[0108] From Tables 1 and 2, it can be seen that the metalworking fluids prepared from the water-soluble metalworking oils of Examples 1 to 20 suppressed the volatilization of alkaline components, maintained their pH even when heated, and had good corrosion resistance. Therefore, it is believed that the metalworking fluids obtained from these water-soluble metalworking oils can maintain their performance for a long period of time even in a heated environment. On the other hand, as can be seen from Tables 3 and 4, the metalworking fluids prepared from the water-soluble metalworking oils of Comparative Examples 1 to 4 had some oils that did not sufficiently suppress the volatilization of the alkaline components, and also showed a decrease in pH and a decrease in decay resistance in a heated environment.

Claims

1. It contains two or more amine compounds (A) and fatty acids (B), the volatilization rate calculated from the following formula (i) when heated at 50°C for 48 hours is 20% or less, A water-soluble metalworking fluid in which the content of amine compound (X), which is not part of component (A), is less than 5.0 parts by mass per 100 parts by mass of the total amount of component (A). Formula (i): Volatility (%) = ([Mass of amine compound before heating] - [Mass of amine compound after heating for 48 hours]) / [Mass of amine compound before heating] × 100

2. The water-soluble metalworking fluid according to claim 1, wherein the content of component (A) is more than 5.0% by mass on a total basis of the water-soluble metalworking fluid.

3. The water-soluble metalworking fluid according to claim 1 or 2, wherein component (A) comprises at least two amine compounds (A1) having a volatility rate of 10% or less.

4. The water-soluble metalworking fluid according to claim 1 or 2, wherein the total content of polyalkylene glycol (Y1) having a weight-average molecular weight of 12,000 or less and a water-insoluble compound (Y2) having a polyoxyalkylene group is less than 70% by mass on a total basis of the water-soluble metalworking fluid.

5. The water-soluble metalworking fluid according to claim 1 or 2, wherein the content of polyalkylene glycol (Y1) having a weight-average molecular weight of 12,000 or less is less than 15.0% by mass on a total basis of the water-soluble metalworking fluid.

6. The water-soluble metalworking fluid according to claim 1 or 2, wherein the content of a water-insoluble compound (Y2) having a polyoxyalkylene group is less than 15.0% by mass on a total basis of the water-soluble metalworking fluid.

7. The water-soluble metalworking fluid according to claim 1 or 2, wherein the content of component (B) is 5.0% by mass or more based on the total amount of the water-soluble metalworking fluid.

8. The water-soluble metalworking fluid according to claim 1 or 2, wherein the ratio of the base value derived from component (A) to the acid value derived from component (B) [(A) / (B)] is 0.50 to 10.

0.

9. The water-soluble metalworking fluid according to claim 1 or 2, further containing a nonionic surfactant (C).

10. The water-soluble metalworking fluid according to claim 1 or 2, further containing a base oil (D).

11. The water-soluble metalworking fluid according to claim 1 or 2, further containing water (E).

12. A metalworking fluid comprising the water-soluble metalworking oil according to claim 1 or 2, with diluting water added.

13. A metalworking method comprising applying the metalworking fluid described in claim 12 to a workpiece made of metal.