Water-soluble processing oil composition and metalworking method

Abstract

To provide a water-soluble processing oil composition capable of maintaining a foaming suppressing effect, and a metal processing method using the water-soluble processing oil composition.SOLUTION: A water-soluble processing oil composition comprises: a base oil (A); and a silicone antifoaming agent (B) modified with a polyalkylene oxide modifying group, wherein the silicone antifoaming agent (B) has a weight average molecular weight of more than 26,000.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a water-soluble processing oil composition and a metalworking method. [Background technology]

[0002] When performing metalworking operations such as turning, planing, drilling, and milling on steel or non-ferrous metal materials, machining fluid compositions are used for purposes such as reducing friction between the tool and the workpiece or chips, removing chips, preventing the formation of built-up edges, suppressing heat generation, or cooling. Generally, machining fluid compositions are broadly classified into non-water-soluble machining fluid compositions whose main purpose is lubrication and water-soluble machining fluid compositions whose main purpose is cooling.

[0003] For example, water-soluble cutting fluid compositions, a type of water-soluble machining fluid composition, are classified into A1, A2, and A3 types according to JIS K2241. All of these are used after being diluted with water. While A3 consists only of water-soluble components, A1 and A2 also contain water-insoluble components. Therefore, A1 and A2 are emulsions containing surfactants. Type A1 is called an emulsion, and Type A2 is called a soluble, and they have higher workability compared to Type A3. This high workability is often due to the presence of water-insoluble components. Therefore, when using Type A1 or A2, it is important to ensure that the water-insoluble components are stably emulsified when diluting Type A1 or A2 before using them for metal processing.

[0004] Surfactants are generally used to maintain a stable emulsified state, but the inclusion of surfactants can sometimes cause the water-soluble processing oil composition to foam excessively. For example, in some machining processes, a water-soluble machining oil composition is supplied to the machining point under high pressure. In such cases, a large amount of foam may be generated, causing problems such as overflow from the tank. Generally, defoaming agents are used to suppress this type of foaming.

[0005] For example, Patent Document 1 discloses a water-soluble cutting fluid stock solution composition containing, on a total basis of the composition, (A) 15 to 50% by mass of a block-type polyoxyalkylene compound of a specific structure, (B) 1.0 to 15% by mass of a fatty acid having 8 to 10 carbon atoms, and (C) at least one basic compound selected from alkali metal hydroxides, aliphatic amines, alicyclic amines, aromatic amines, alkanolamines, polyamines, and nitrogen-containing compounds of a specific structure, in an amount equal to or greater than the neutralization equivalent of component (B), and in a range where the total amount of components (B) and (C) is 1.1 to 85% by mass, and further containing 0 to 60% by mass of water. The water-soluble cutting fluid stock solution composition described in Patent Document 1 is said to produce little foam even when supplied under high pressure. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 08-239683 [Overview of the project] [Problems that the invention aims to solve]

[0007] It is preferable that the water-soluble processing oil composition maintains a stable dispersion of the defoaming agent within the oil (hereinafter referred to as "defoaming agent stability") in both its undiluted state at the time of manufacture and sale, and its diluted state when used for processing. If the stability of the defoaming agent in the water-soluble processing oil composition in its undiluted state is poor, for example, the defoaming agent may settle in the water-soluble processing oil composition. In that case, when diluting the water-soluble processing oil composition, only the supernatant containing almost no defoaming agent may be collected, and the resulting diluted product may not be able to suppress foaming when used for processing. Furthermore, if the stability of the defoaming agent in a water-soluble processing oil composition diluted with water is poor, for example, the defoaming agent in the water-soluble processing oil composition may settle in the tank, making it impossible to suppress foaming when the oil is used for processing. In conventional water-soluble machining oil compositions such as the water-soluble cutting oil agent stock solution composition of Patent Document 1 described above, there is room for improvement in the stability of the antifoaming agent in the water-soluble machining oil composition in the stock solution state and in the state diluted with water when used for machining.

[0008] In view of the above circumstances, the present invention has been made, and an object thereof is to provide a water-soluble machining oil composition capable of maintaining an anti-foaming effect, and a metal processing method using the water-soluble machining oil composition.

Means for Solving the Problems

[0009] As a result of intensive studies, the inventors have found that by using a base oil and a silicone-based antifoaming agent having a specific molecular weight and modified with a polyalkylene oxide modification group, the dispersibility and stability of the silicone-based antifoaming agent in the water-soluble machining oil composition are improved in both the stock solution state and the state diluted with water when used for machining. That is, with the above specific configuration, a water-soluble machining oil composition having good anti-foaming properties even when the stock solution is diluted and not having a decrease in anti-foaming properties even when the stock solution is stored for a long time has been found, and the present invention has been completed. Specifically, the present invention employs the following configurations.

[0010] [1] A water-soluble machining oil composition containing a base oil (A) and a silicone-based antifoaming agent (B) modified with a polyalkylene oxide modification group, wherein the weight average molecular weight of the silicone-based antifoaming agent (B) is more than 26,000. [2] The water-soluble machining oil composition according to [1], wherein the modification rate of the silicone-based antifoaming agent (B) is more than 0.12% and less than 2.38%. [3] The water-soluble machining oil composition according to [1] or [2], wherein the molecular weight of the polyalkylene oxide modification group in the silicone-based antifoaming agent (B) is 5000 or more. [4] The water-soluble machining oil composition according to any one of [1] to [3], further containing at least one surfactant selected from the group consisting of a nonionic surfactant and an anionic surfactant. [5] The kinematic viscosity of the base oil (A) at 40°C is 10 mm 2 / s or more 100mm 2 A water-soluble processing oil composition according to any one of items [1] to [4], wherein the s is less than or equal to / s. [6] A water-soluble machining oil composition according to any one of [1] to [5], used for cutting or grinding metals. [7] The water-soluble processing oil composition according to [6], wherein the metal comprises one or more metals selected from the group consisting of aluminum, aluminum alloys, copper, copper alloys, iron, and iron alloys. A metalworking method comprising: a dilution step of diluting a water-soluble processing oil composition described in any one of items [8][1] to [5] with water; and a processing step of processing a metal using the diluted water-soluble processing oil composition. [Effects of the Invention]

[0011] According to the present invention, it is possible to provide a water-soluble processing oil composition that can maintain a foaming suppression effect, and a metal processing method using the water-soluble processing oil composition. [Brief explanation of the drawing]

[0012] [Figure 1] This is a schematic diagram showing a foaming test apparatus. [Modes for carrying out the invention]

[0013] In this specification, "viscosity index" means the viscosity index measured in accordance with JIS K 2283:2000. In this specification, "sulfur content" refers to the value measured in accordance with JIS K 2541-6:2013. In this specification, "saturation content" refers to the value measured in accordance with ASTM D 2007-93.

[0014] In this specification, the "naphthene content" and the "paraffin content" are values for determining these ratios based on the molecular ion intensity obtained by mass spectrometry using FI ionization (with a glass reservoir). The measurement method is specifically shown below.

[0015] (1) Fill a 18 mm diameter and 980 mm long adsorption tube for elution chromatography with 120 g of silica gel having a nominal diameter of 74 - 149 μm (grade 923 manufactured by Fuji Silysia Chemical Ltd.) activated by drying at about 175°C for 3 hours. (2) Inject 75 mL of n - pentane to pre - wet the silica gel. (3) Weigh accurately about 2 g of the sample, dilute it with an equal volume of n - pentane, and inject the resulting sample solution. (4) When the liquid level of the sample solution reaches the upper end of the silica gel, inject 140 mL of n - pentane to separate the saturated hydrocarbon components, and collect the eluate from the lower end of the adsorption tube. (5) Apply the eluate to a rotary evaporator to distill off the solvent and obtain the saturated hydrocarbon components. (6) Perform type analysis on the saturated hydrocarbon components using a mass spectrometer. As the ionization method in mass spectrometry, the FI ionization method using a glass reservoir is used, and the mass spectrometer used is JMS - AX505H manufactured by JEOL Ltd.

[0016] The measurement conditions are shown below. Acceleration voltage: 3.0 kV, cathode voltage: - 5 to - 6 kV, resolution: about 500, emitter: carbon, emitter current: 5 mA, measurement range: mass number 35 - 700, auxiliary oven temperature: 300°C, separator temperature: 300°C, main oven temperature: 350°C, sample injection volume: 1 μL.

[0017] The molecular ions obtained by mass spectrometry, after isotope correction, from their mass numbers, paraffins (C n H 2n+2 ) and naphthenes (C n H 2n , C n H 2n-2 , C n H 2n-4The materials are classified and organized into two types, and the fraction of each ionic strength is determined to determine the content of each type relative to the total saturated hydrocarbon components. Then, based on the content of saturated hydrocarbon components, the respective content of paraffin and naphthene relative to the total sample is determined.

[0018] Further details regarding data processing using type analysis for FI mass spectrometry are described in "Nisseki Review," Vol. 33, No. 4, pp. 135-142, particularly in section "2.2.3 Data Processing."

[0019] In this specification, "aromatic content" means the value measured in accordance with the fluorescent indicator adsorption method of JIS K 2536-1:2003 "Petroleum products - Test methods for components".

[0020] In this specification, "kinematic viscosity at 40°C" refers to the kinematic viscosity (mm³) measured at 40°C in accordance with JIS K 2283:2000. 2 It means / s).

[0021] In this specification, "weight-average molecular weight Mw" refers to the polystyrene-equivalent value obtained by gel permeation chromatography (GPC) using the following measuring equipment and measurement conditions. Equipment used: Shimadzu Corporation Prominence series Detector: RID-10A Column: Shodex KF-405LHQ Mobile phase: THF Flow rate: 0.5mL / min Concentration: 5,000mg / L Calibration material: Polystyrene

[0022] (Water-soluble processing oil composition) The water-soluble processing oil composition of this embodiment contains a base oil (A) and a silicone-based defoaming agent (B) modified with a polyalkylene oxide modified group (hereinafter also referred to as "silicone-based defoaming agent (B)").

[0023] <Base oil (A)> Examples of the base oil (A) in the water-soluble processing oil composition of this embodiment include mineral oil and synthetic oil.

[0024] Mineral oil Specifically, examples of mineral oil include mineral oil obtained by applying one or more refining methods such as solvent delamination, solvent extraction, hydrocracking, solvent dewaxing, catalytic dewaxing, hydrorefining, sulfuric acid washing, and clay treatment to a lubricating oil fraction obtained by atmospheric distillation and vacuum distillation of crude oil.

[0025] As for the mineral oil, you can use base oils of API Group I (hereinafter sometimes referred to as "API Group I base oil"), Group II (hereinafter sometimes referred to as "API Group II base oil"), or Group III (hereinafter sometimes referred to as "API Group III base oil"), or a mixture thereof. API Group I base oils are mineral oil-based base oils having a sulfur content of more than 0.03% by mass and / or a saturation content of less than 90% by mass, and a viscosity index of 80 or more and less than 120. API Group II base oils are mineral oil-based base oils with a sulfur content of 0.03% by mass or less, a saturation content of 90% by mass or more, and a viscosity index of 80 or more and less than 120. API Group III base oils are mineral oil-based base oils with a sulfur content of 0.03% by mass or less, a saturation content of 90% by mass or more, and a viscosity index of 120 or higher.

[0026] The base oil (A) may consist of one type of mineral oil, or it may be a blended base oil containing two or more types of mineral oil. In the case of a blended base oil containing two or more types of mineral oil, the API classifications of those mineral oils may be the same or they may be different from one another. From the viewpoint of the stability of the defoaming agent in the water-soluble processing oil composition, it is preferable that the mineral oil in base oil (A) contains an API group I base oil or an API group II base oil.

[0027] When the base oil (A) is an API group I base oil, the paraffin content in the base oil is preferably 45% by volume or more, more preferably 55% by volume or more, and even more preferably 65% ​​by volume or more, from the viewpoint of the working environment (low odor). Furthermore, from the viewpoint of composition stability, the paraffin content in the base oil is preferably 90% by volume or less, more preferably 80% by volume or less, and even more preferably 70% by volume or less. In one embodiment, the paraffin content in the base oil is preferably 45% by volume or more and 90% by volume or less, more preferably 55% by volume or more and 80% by volume or less, and even more preferably 65% ​​by volume or more and 70% by volume or less.

[0028] When the base oil (A) is an API group I base oil, the naphthene content in the base oil is preferably 5% by volume or more, more preferably 15% by volume or more, and even more preferably 25% by volume or more, from the viewpoint of composition stability. Furthermore, the naphthene content in the base oil is preferably 50% by volume or less, more preferably 40% by volume or less, and even more preferably 30% by volume or less, from the viewpoint of the working environment (low odor). In one embodiment, the naphthenic content in the base oil is preferably 5% by volume or more and 50% by volume or less, more preferably 15% by volume or more and 40% by volume or less, and even more preferably 25% by volume or more and 30% by volume or less.

[0029] When the base oil (A) is an API group I base oil, the aromatic content in the base oil is preferably 10% by volume or less, more preferably 8% by volume or less, and even more preferably 6% by volume or less.

[0030] For example, if the base oil (A) is an API group I base oil, it is preferable that the API group I base oil has a paraffin content of 60% to 70% by volume, a naphthene content of 20% to 30% by volume, and an aromatic content of 10% or less by volume.

[0031] When the base oil (A) is an API group II base oil, the paraffin content in the base oil is preferably 50% by volume or more, more preferably 60% by volume or more, and even more preferably 70% by volume or more. Furthermore, the paraffin content in the base oil is preferably 95% by volume or less, more preferably 90% by volume or less, and even more preferably 85% by volume or less. In one embodiment, the paraffin content in the base oil is preferably 50% by volume or more and 95% by volume or less, more preferably 60% by volume or more and 90% by volume or less, and even more preferably 70% by volume or more and 85% by volume or less.

[0032] When the base oil (A) is an API group II base oil, the naphthene content in the base oil is preferably 5% by volume or more, more preferably 10% by volume or more, and even more preferably 15% by volume or more. Furthermore, the naphthene content in the base oil is preferably 50% by volume or less, more preferably 40% by volume or less, and even more preferably 30% by volume or less. In one embodiment, the naphthenic content in the base oil is preferably 5% by volume or more and 50% by volume or less, more preferably 10% by volume or more and 40% by volume or less, and even more preferably 15% by volume or more and 30% by volume or less.

[0033] When the base oil (A) is an API group II base oil, the aromatic content in the base oil is preferably 5% by volume or less, more preferably 3% by volume or less, and even more preferably 1% by volume or less, and may be below the detection limit.

[0034] For example, if the base oil (A) is an API group II base oil, it is preferable that the API group II base oil has a paraffin content of 70% to 85% by volume, a naphthene content of 15% to 30% by volume, and an aromatic content of 1% or less by volume.

[0035] When the base oil (A) is an API group III base oil, the paraffin content in the base oil is preferably 60% by volume or more, more preferably 65% ​​by volume or more, and even more preferably 70% by volume or more. Furthermore, the paraffin content in the base oil is preferably 95% by volume or less, more preferably 90% by volume or less, and even more preferably 85% by volume or less. In one embodiment, the paraffin content in the base oil is preferably 60% to 95% by volume, more preferably 65% ​​to 90% by volume, and even more preferably 70% to 85% by volume.

[0036] When the base oil (A) is an API group III base oil, the naphthene content in the base oil is preferably 5% by volume or more, more preferably 10% by volume or more, and even more preferably 15% by volume or more. Furthermore, the naphthene content in the base oil is preferably 40% by volume or less, more preferably 35% by volume or less, and even more preferably 30% by volume or less. In one embodiment, the naphthene content in the base oil is preferably 5% to 40% by volume, more preferably 10% to 35% by volume, and even more preferably 15% to 30% by volume.

[0037] When the base oil (A) is an API group III base oil, the aromatic content in the base oil is preferably 5% by volume or less, more preferably 3% by volume or less, and even more preferably 1% by volume or less, and may be below the detection limit.

[0038] For example, if the base oil (A) is an API group III base oil, it is preferable that the API group III base oil has a paraffin content of 70% to 85% by volume, a naphthene content of 15% to 30% by volume, and an aromatic content of 1% or less by volume.

[0039] ≪Synthetic oil≫ Examples of synthetic oils include polyolefins and alkylbenzenes.

[0040] • Polyolefins Examples of polyolefins include homopolymers or copolymers of olefin monomers having 2 to 16 carbon atoms, preferably 2 to 12 carbon atoms, and hydrides of these polymers. The olefin monomer may be any of α-olefins, internal olefins, linear olefins, or branched olefins. Specific examples of such olefin monomers include ethylene, propylene, 1-butene, 2-butene, isobutene, pentene, hexene, heptene, octene, nonene, decene, undecene, dodecene, tridecene, tetradecene, pentadecene, hexadecene, and mixtures thereof.

[0041] Alkylbenzene Preferably, the alkylbenzene has 1 to 4 alkyl groups with 1 to 40 carbon atoms in its molecule. The alkyl groups of the alkylbenzene may be linear or branched, but branched alkyl groups are preferred in terms of stability and viscosity properties, and branched alkyl groups derived from olefin oligomers such as propylene, butene, and isobutylene are more preferred because they are readily available.

[0042] The base oil (A) of the water-soluble processing oil composition of this embodiment may be one of the above-mentioned mineral oils and / or synthetic oils used individually, or two or more may be used in mixture form. However, it is preferable to use one of the above-mentioned mineral oils individually or to use two or more in mixture form.

[0043] The kinematic viscosity of the base oil (A) of the water-soluble machining oil composition of this embodiment at 40°C is preferably 4 mm from the viewpoint of machineability. 2 / s or more, more preferably 6 mm 2 / s or more, and more preferably 8mm 2 It is / s or greater. Furthermore, the kinematic viscosity of the base oil (A) at 40°C is preferably 100 mm from the viewpoint of the removeability of the composition after processing. 2 / s or less, more preferably 80mm 2 / s or less, and more preferably 60 mm 2 It is less than or equal to / s. In one embodiment, the kinematic viscosity of the base oil (A) at 40°C is preferably 4 mm². 2 / s or more 100mm 2 / s or less, more preferably 6mm 2 / s or more 80mm 2 / s or less, and more preferably 8mm 2 / s or more 60mm 2 It is less than or equal to / s.

[0044] The base oil (A) content of the water-soluble processing oil composition of this embodiment is preferably 1% by mass or more, more preferably 3% by mass or more, and even more preferably 5% by mass or more, based on the total amount of the water-soluble processing oil composition. Furthermore, the base oil (A) content is preferably 50% by mass or less, more preferably 40% by mass or less, and even more preferably 30% by mass or less, based on the total amount of the water-soluble processing oil composition. In one embodiment, the base oil (A) content is preferably 1% by mass or more and 50% by mass or less, more preferably 3% by mass or more and 40% by mass or less, and even more preferably 5% by mass or more and 30% by mass or less, based on the total amount of the water-soluble processing oil composition.

[0045] <Silicone-based defoaming agent (B)> In this embodiment, the silicone-based defoaming agent (B) is a synthetic polymer compound having a main skeleton of siloxane bonds (Si-O-Si bonds), a portion of which is modified by a polyalkylene oxide modifying group, and the weight-average molecular weight of the silicone-based defoaming agent (B) is greater than 26,000. In the water-soluble processing oil composition of this embodiment, the dispersibility of the silicone-based defoaming agent (B) in the base oil (A) described above is improved by using the above-described configuration for the silicone-based defoaming agent (B).

[0046] In the water-soluble processing oil composition of this embodiment, the silicone-based defoaming agent (B) preferably has a dimethyl silicone skeleton.

[0047] The silicone-based defoamer (B) may consist of a randomly repeated arrangement of structural units modified by a polyalkylene oxide modification group and unmodified structural units, or it may consist of a long continuous arrangement of the same type of structural units.

[0048] Examples of silicone-based defoaming agents (B) include side-chain modified silicone-based defoaming agents represented by the following general formula (b-1), both-end modified silicone-based defoaming agents represented by the following general formula (b-2), one-end modified silicone-based defoaming agents represented by the following general formula (b-3), and both-end modified silicone-based defoaming agents represented by the following general formula (b-4).

[0049] [ka] [In the formula, X is independently a polyalkylene oxide modified group. m1 to m4 independently represent the number of repetitions of the unmodified constituent unit [-(CH3)2SiO-]. n1 to n4 independently represent the number of repetitions of the constituent unit modified by the polyalkylene oxide modified group.]

[0050] In the above general formulas (b-1) to (b-4), m1 to m4 and n1 to n4 are appropriately adjusted so that the weight-average molecular weight of the silicone-based defoamer (B) exceeds 26,000.

[0051] The polyalkylene oxide modifying group is preferably a group represented by the following general formula (X-1).

[0052] [ka] [In the formula, R 1 ~R 3 These are each an alkylene group independently. p is (-OR 2 This indicates the number of repetitions of (-OR). q is (-OR 3 -) indicates the number of repetitions. * indicates a combination.

[0053] In the above general formula (X-1), R 1 ~R 3 These are, independently, alkylene groups. The alkylene group is preferably an alkylene group having 1 to 10 carbon atoms, more preferably an alkylene group having 1 to 6 carbon atoms, and even more preferably an alkylene group having 1 to 4 carbon atoms.

[0054] Examples of linear alkylene groups having 1 to 4 carbon atoms include the methylene group, the ethylene group [-(CH2)2-], the trimethylene group [-(CH2)3-], and the tetramethylene group [-(CH2)4-]. Examples of branched alkylene groups having 2 to 4 carbon atoms include alkylmethylene groups such as -CH(CH3)-, -CH(CH2CH3)-, -C(CH3)2-, and -C(CH3)(CH2CH3)-; alkylethylene groups such as -CH2CH(CH3)-, -CH(CH3)CH2-, -CH(CH3)CH(CH3)-, -C(CH3)2CH2-, and -CH(CH2CH3)CH2-; and alkylalkylene groups such as alkyltrimethylene groups such as -CH(CH3)CH2CH2- and -CH2CH(CH3)CH2-.

[0055] In the above general formula (X-1), R 1 ~R 3 Among the above, the ethylene group [-(CH2)2-] or the propylene group {[-CH2CH(CH3)-] or [-CH(CH3)CH2-]} is preferred, independently of each other.

[0056] (-OR) in p and q 2 The number of repetitions of -) and (-OR 3 The number of repetitions of -) is adjusted as appropriate, for example, as described later, so that the molecular weight of the polyalkylene oxide modified group is preferably 5000 or more.

[0057] In the water-soluble processing oil composition of this embodiment, the silicone-based defoaming agent (B) is preferably a dimethyl silicone modified with a group in which polyethylene oxide groups and polypropylene oxide groups are linked (hereinafter also referred to as "EOPO-modified dimethyl silicone").

[0058] In this embodiment, the weight-average molecular weight of the silicone-based defoaming agent (B) is greater than 26,000, preferably 30,000 or more, more preferably 35,000 or more, even more preferably 38,000 or more, and particularly preferably 40,000 or more. On the other hand, the upper limit of the weight-average molecular weight of the silicone-based defoamer (B) is preferably 100,000 or less, more preferably 70,000 or less, even more preferably 50,000 or less, and particularly preferably 45,000 or less.

[0059] If the weight-average molecular weight of the silicone-based defoamer (B) in this embodiment is above the lower limit, the dispersibility of the silicone-based defoamer (B) in the base oil (A) in its undiluted state is improved. Furthermore, when diluted with water for processing, the insolubility of the silicone-based defoamer (B) in water becomes appropriate, improving the defoaming effect. If the weight-average molecular weight of the silicone-based defoaming agent (B) in this embodiment is below the above preferred upper limit, the defoaming effect will be further improved.

[0060] In one embodiment, the weight-average molecular weight (Mw) of the silicone-based defoamer (B) is preferably 30,000 to 100,000, more preferably 35,000 to 70,000, even more preferably 38,000 to 50,000, and particularly preferably 40,000 to 45,000.

[0061] In this embodiment, the modification rate of the silicone-based defoaming agent (B) is preferably greater than 0.12%, more preferably 0.15% or greater, even more preferably 0.18% or greater, and particularly preferably 0.2% or greater. Furthermore, the modification rate of the silicone-based defoaming agent (B) is preferably less than 2.38%, more preferably 2.0% or less, even more preferably 1.5% or less, and particularly preferably 1.0% or less.

[0062] If the modification rate of the silicone-based defoamer (B) in this embodiment is above the above preferred lower limit, the dispersibility of the silicone-based defoamer (B) in a water-diluted state when subjected to processing will be further improved. If the modification rate of the silicone-based defoaming agent (B) in this embodiment is below the above preferred upper limit, the dispersibility of the silicone-based defoaming agent (B) in the base oil (A) in its undiluted state will be further improved.

[0063] In one embodiment, the modification rate of the silicone-based defoamer (B) is preferably more than 0.12% and less than 2.38%, more preferably 0.15% or more and 2.0%, even more preferably 0.18% or more and 1.5%, and particularly preferably 0.2% or more and 1.0%.

[0064] [Method for calculating the modification rate of silicone-based defoaming agent (B)] Using a silicone-based defoamer (B0) having constituent units represented by the general formula (b-0) below as an example, the method for calculating the modification rate of the silicone-based defoamer (B) is shown below.

[0065] [ka] [In the formula, Xa is a polyalkylene oxide modified group. ma indicates the number of repeats of the unmodified constituent unit [-(CH3)2SiO-]. na indicates the number of repeats of the constituent unit modified by the polyalkylene oxide modified group.]

[0066] (i) In the structural unit modified by the polyalkylene oxide modification group of the silicone-based defoamer (B0), the peak area HxP attributed to the hydrogen atom Hx of CH2 bonded to Si is, 1 Determined by 1H-NMR measurement. 1In 1H-NMR measurements, the peak area for each hydrogen atom is considered to be "1," so the resulting peak area HxP is "2." Dividing the peak area HxP "2" by the number of hydrogen atoms Hx (2) gives the number of constituent units na modified by the polyalkylene oxide modification group.

[0067] (ii) In the unmodified constituent unit of the silicone-based defoamer (B0), the peak area HyP attributed to the hydrogen atom Hy of CH3 bonded to Si is, 1 This is determined by 1H-NMR measurement. By subtracting the peak area "3" that is attributed to the hydrogen atoms Hy of CH3 in the modified constituent units with polyalkylene oxide modification groups from the peak area HyP, the peak area HyP1 that is attributed to the hydrogen atoms Hy of CH3 in the unmodified constituent units can be calculated. Next, the value obtained by dividing this peak area HyP1 by the number of hydrogen atoms Hy in the unmodified constituent units (6) is the number of unmodified constituent units ma.

[0068] (iii) As shown in formula (1a) below, the ratio of the number of constituent units modified by the polyalkylene oxide modifying group na to the number of unmodified constituent units ma can be calculated by the calculations in (i) and (ii) above. na:ma=2 / 2:(HyP-3) / 6···(1a)

[0069] (iv) The modification rate of the silicone-based defoamer (B0) can be determined by the following formula (2a). Degeneration rate (%) = na / (ma+na) × 100 ... (2a)

[0070] 1 The measurement equipment and conditions used for H-NMR measurement are as follows: Equipment used: Bruker AVANCE III HD-cryo600 NMR spectrometer. 1 H resonance frequency: 600.18MHz Solvent: CDCl3 Concentration: Approximately 50mg / mL Measurement method: 1 H Non-Decoupling Method Pulse width: 30° pulse Waiting time: 5 seconds Chemical shift standard: CHCl3 in CDCl3 (7.28 ppm)

[0071] In this embodiment, the molecular weight of the polyalkylene oxide modified group of the silicone-based defoaming agent (B) is preferably 5000 or more, more preferably 5300 or more, even more preferably 5500 or more, and particularly preferably 6000 or more. Furthermore, the molecular weight of the polyalkylene oxide modified group of the silicone-based defoaming agent (B) is preferably 10,000 or less, more preferably 9,000 or less, even more preferably 8,000 or less, and particularly preferably 7,500 or less.

[0072] If the molecular weight of the polyalkylene oxide modified group of the silicone-based defoamer (B) in this embodiment is above the above preferred lower limit, the dispersibility of the silicone-based defoamer (B) in a water-diluted state when subjected to processing will be further improved. If the molecular weight of the polyalkylene oxide modified group of the silicone-based defoamer (B) in this embodiment is below the above preferred upper limit, the dispersibility of the silicone-based defoamer (B) in the base oil (A) in its undiluted state is further improved.

[0073] In one embodiment, the molecular weight of the polyalkylene oxide modified group of the silicone-based defoamer (B) is preferably 5,000 to 10,000, more preferably 5,300 to 9,000, even more preferably 5,500 to 8,000, and particularly preferably 6,000 to 7,500.

[0074] [Method for calculating the molecular weight of the polyalkylene oxide modified group in silicone-based defoamer (B)] The molecular weight of the polyalkylene oxide modified group of the silicone-based defoamer (B) can be calculated if the structure of the modified group and the number of repeating alkylene oxide units are known.

[0075] As an example, a silicone-based defoamer having a modified group X0 represented by the following formula (x-0) is used, and the method for calculating the molecular weight of the polyalkylene oxide modified group of the silicone-based defoamer (B) is shown below.

[0076] [ka] [In the formula, pa represents the number of (-O-CH2CH2-) repeats. qa represents the number of (-O-CH2(CH3)CH-) repeats. * represents a bond.]

[0077] (i) The number of repetitions qa of (-O-CH2(CH3)CH-) is given by the peak area HdP attributed to the hydrogen atom Hd of CH3 in the constituent unit (-O-CH2(CH3)CH-), as shown in equation (ia) below. 1 It can be determined by measuring 1H-NMR and then calculating the peak area HdP by dividing it by the number of hydrogen atoms Hd (3). qa = HdP / 3···(ia)

[0078] (ii) The number of repetitions of (-O-CH2CH2-) pa can be calculated by subtracting the peak area HdP (assigned to hydrogen atoms Hd) and the peak area HaP (assigned to hydrogen atoms Ha) from the peak area HcP (assigned to hydrogen atoms Hc), as shown in the following formula (iia), and then dividing the result by the number of hydrogen atoms Hc in (-O-CH2CH2-) (4). pa = (HcP - HdP - HaP) / 4 ... (iia)

[0079] (iii) The modifying group X0 is as shown in formula (iiia) below, The molecular weight of the (-CH2CH2CH2-) group that binds to the main chain of the silicone-based defoamer (B) is 42, The molecular weight of (-O-CH2CH2-) is 44, multiplied by the number of repeats (pa) obtained in (iia), The molecular weight of (-O-CH2(CH3)CH-) is 58, multiplied by the number of repeats qa obtained in (ia), It can be calculated by adding the molecular weight of the terminal -OH group (17) to the molecular weight of the terminal -OH group. Molecular weight of modified group X0 = 42 + 44 × pa + 58 × qa + 17 ... (iiia)

[0080] [Method for manufacturing silicone-based defoaming agent (B)] The silicone-based defoaming agent (B) of this embodiment can be produced, for example, by adding two or more polyoxyalkylene compounds having vinyl or allyl groups at the end of their molecular chains and unsaturated olefins having 3 to 20 carbon atoms to a methylpolysiloxane containing a ≡SiH group in the presence of a platinum catalyst. Furthermore, the rate of modification of the silicone-based defoamer (B) described above can be adjusted by adjusting the amount of the polyoxyalkylene compound added and the reaction conditions. Furthermore, by adjusting the type and degree of polymerization of the polyoxyalkylene compound, the molecular weight of the polyalkylene oxide modified group in the silicone-based defoamer (B) described above can be adjusted.

[0081] The content of the silicone-based defoaming agent (B) in the water-soluble processing oil composition of this embodiment is preferably 0.0005% by mass or more, more preferably 0.001% by mass or more, and even more preferably 0.005% by mass or more, based on the total amount of the water-soluble processing oil composition. Furthermore, the content of the silicone-based defoaming agent (B) is preferably 3% by mass or less, more preferably 1% by mass or less, and even more preferably 0.5% by mass or less, based on the total amount of the water-soluble processing oil composition. In one embodiment, the content of the silicone-based defoaming agent (B) is preferably 0.0005% by mass or more and 3% by mass or less, more preferably 0.001% by mass or more and 1% by mass or less, and even more preferably 0.005% by mass or more and 0.5% by mass or less, based on the total amount of the water-soluble processing oil composition.

[0082] The content of the silicone-based defoaming agent (B) in the water-soluble processing oil composition of this embodiment is preferably 0.1 parts by mass or more, more preferably 0.5 parts by mass or more, and even more preferably 0.8 parts by mass or more, per 100 parts by mass of the base oil (A). Furthermore, the content of the silicone-based defoaming agent (B) is preferably 5 parts by mass or less, more preferably 3 parts by mass or less, and even more preferably 1 part by mass or less, per 100 parts by mass of base oil (A). In one embodiment, the content of the silicone-based defoaming agent (B) is preferably 0.1 parts by mass or more and 5 parts by mass or less, more preferably 0.5 parts by mass or more and 3 parts by mass or less, and even more preferably 0.8 parts by mass or more and 1 part by mass or less, per 100 parts by mass of the base oil (A).

[0083] The water-soluble processing oil composition of this embodiment may contain one silicone-based defoaming agent (B) alone, or it may contain two or more types.

[0084] <Optional ingredients> The water-soluble processing oil composition of this embodiment may further contain components other than the base oil (A) and the silicone-based defoaming agent (B) described above (optional components), as long as the effects of the present invention are not impaired. Optional components include surfactants (C), extreme pressure agents (D), water (W), oiliness agents (E), rust inhibitors (F), antioxidants such as phenols and amines; mist inhibitors such as polyisobutene and poly-α-olefins; metal deactivators such as benzotriazole and its derivatives; disinfectants; and anti-spoilage agents. The water-soluble processing oil composition of this embodiment preferably contains a base oil (A), a silicone-based defoaming agent (B), a surfactant (C), an extreme pressure agent (D), water (W), and an oiliness agent (E), and more preferably contains a base oil (A), a silicone-based defoaming agent (B), a surfactant (C), an extreme pressure agent (D), water (W), an oiliness agent (E), and a rust inhibitor (F).

[0085] <<Surfactants (C)>> The water-soluble processing oil composition of this embodiment preferably further contains a surfactant (C). The surfactant (C) is preferably a nonionic surfactant or an anionic surfactant, and more preferably a nonionic surfactant.

[0086] Examples of nonionic surfactants include higher alcohol ethylene oxide adducts, alkylphenol ethylene oxide adducts, fatty acid ethylene oxide adducts, higher alkylamine ethylene oxide adducts, fatty acid esters of sorbitol and sorbitan, sucrose fatty acid esters, fluorine-based surfactants, and Pluronic® surfactants.

[0087] Among the nonionic surfactants in the water-soluble processing oil composition of this embodiment, it is preferable that it contains a pluronic surfactant. Pluronic surfactants are nonionic surfactants of the triblock copolymer type, consisting of hydrophilic ethylene oxide (EO) and hydrophobic propylene oxide (PO). Their surfactant properties can be altered by changing the EO / PO polymerization degree.

[0088] Examples of anionic surfactants include aliphatic carboxylates, sulfonates, sulfate esters, and phosphate esters.

[0089] If the water-soluble processing oil composition of this embodiment contains a surfactant (C), the amount of surfactant (C) is preferably 15% by mass or more, more preferably 20% by mass or more, and even more preferably 25% by mass or more, based on the total amount of the water-soluble processing oil composition. Furthermore, the content of surfactant (C) is preferably 40% by mass or less, more preferably 35% by mass or less, and even more preferably 30% by mass or less, based on the total amount of the water-soluble processing oil composition. In one embodiment, the content of surfactant (C) is preferably 15% to 40% by mass, more preferably 20% to 35% by mass, and even more preferably 25% to 30% by mass, based on the total amount of the water-soluble processing oil composition.

[0090] The water-soluble processing oil composition of this embodiment may contain one surfactant (C) alone, or it may contain two or more surfactants.

[0091] ≪Extreme pressure agent (D)≫ The water-soluble processing oil composition of this embodiment preferably further contains an extreme pressure agent (D). Examples of extreme pressure agents (D) include dihydrocarbyl polysulfide, sulfur esters (including sulfur ester oils and fats), sulfurized fatty acids, sulfurized mineral oil, zinc dithiophosphate compounds, zinc dithiocarbamate compounds, molybdenum dithiophosphate compounds, and molybdenum dithiocarbamate.

[0092] In this embodiment, the extreme pressure agent (D) of the water-soluble processing oil composition is preferably a sulfurized fatty acid. Specifically, sulfurized fatty acids include oleic acid, linoleic acid, fatty acids extracted from animal and vegetable oils, or mixtures thereof that have been sulfurized by any method. Among these, sulfurized oleic acid is preferred as the extreme pressure agent (D).

[0093] If the water-soluble processing oil composition of this embodiment contains an extreme pressure agent (D), the content of the extreme pressure agent (D) is preferably 3% by mass or more, more preferably 5% by mass or more, and even more preferably 10% by mass or more, based on the total amount of the water-soluble processing oil composition. Furthermore, the content of the extreme pressure agent (D) is preferably 25% by mass or less, more preferably 20% by mass or less, and even more preferably 15% by mass or less, based on the total amount of the water-soluble processing oil composition. In one embodiment, the content of the extreme pressure agent (D) is preferably 3% by mass or more and 25% by mass or less, more preferably 5% by mass or more and 20% by mass or less, and even more preferably 10% by mass or more and 15% by mass or less, based on the total amount of the water-soluble processing oil composition.

[0094] The water-soluble machining oil composition of this embodiment may contain one extreme pressure agent (D) alone, or it may contain two or more extreme pressure agents (D).

[0095] ≪Water (W)≫ The water-soluble processing oil composition of this embodiment preferably further contains water (W). Examples of water (W) include tap water, industrial water, purified water, deionized water, ion-exchanged water, well water, and water absorbed from the atmosphere.

[0096] If the water-soluble processing oil composition of this embodiment contains water (W), the water (W) content is preferably 10% by mass or more, more preferably 15% by mass or more, and even more preferably 20% by mass or more, based on the total amount of the water-soluble processing oil composition. Furthermore, the water (W) content is preferably 35% by mass or less, more preferably 30% by mass or less, and even more preferably 25% by mass or less, based on the total amount of the water-soluble processing oil composition. In one embodiment, the water (W) content is preferably 10% to 35% by mass, more preferably 15% to 30% by mass, and even more preferably 20% to 25% by mass, based on the total amount of the water-soluble processing oil composition.

[0097] ≪Oily-based agent (E)≫ The water-soluble processing oil composition of this embodiment preferably further contains an oily agent (E). Specifically, examples of oily agents (E) include nitrogen-containing compounds, more specifically, primary amines such as ethylamine, n-propylamine, n-butylamine, 1-ethylbutylamine, 1,3-diaminopropane, and cyclohexylamine; secondary amines such as diethylamine, di-n-propylamine, di-n-butylamine, 4,4'-diaminodiphenylamine, diethylenetriamine, tetraethylenepentamine, and N-(2-aminoethyl)ethanolamine; tertiary amines such as dimethylethylamine, diethylmethylamine, triethylamine, tributylamine, triisopropylamine, and dicyclohexylmethylamine; aromatic amines such as N,N-dibutylaniline, N,N-dihexylaniline, 2,6-diisopropylaniline, and 2,4,6-tri(t-butyl)aniline; and alkanolamines such as diethanolamine, monoethanolamine, monoisopropanolamine, diisopropanolamine, and dibutanolamine.

[0098] In the water-soluble processing oil composition of this embodiment, the oily agent (E) is preferably an alkanolamine, more preferably diethanolamine, monoethanolamine, monoisopropanolamine, diisopropanolamine, dibutanolamine, or a mixture thereof, with diisopropanolamine being even more preferred.

[0099] If the water-soluble processing oil composition of this embodiment contains an oily agent (E), the content of the oily agent (E) is preferably 3% by mass or more, more preferably 5% by mass or more, and even more preferably 8% by mass or more, based on the total amount of the water-soluble processing oil composition. Furthermore, the content of the oily agent (E) is preferably 25% by mass or less, more preferably 20% by mass or less, and even more preferably 15% by mass or less, based on the total amount of the water-soluble processing oil composition. In one embodiment, the content of the oily agent (E) is preferably 3% by mass or more and 25% by mass or less, more preferably 5% by mass or more and 20% by mass or less, and even more preferably 8% by mass or more and 15% by mass or less, based on the total amount of the water-soluble processing oil composition.

[0100] When the water-soluble processing oil composition of this embodiment contains an extreme pressure agent (D) and an oiliness agent (E), the content of the oiliness agent (E) is preferably 30 parts by mass or more, more preferably 40 parts by mass or more, and even more preferably 50 parts by mass or more, based on the content of 100 parts by mass of the extreme pressure agent (D). Furthermore, the content of the oily agent (E) is preferably 300 parts by mass or less, more preferably 250 parts by mass or less, and even more preferably 200 parts by mass or less, based on the content of 100 parts by mass of the extreme pressure agent (D). In one embodiment, the content of the oily agent (E) is preferably 30 parts by mass or more and 300 parts by mass or less, more preferably 40 parts by mass or more and 250 parts by mass or less, and even more preferably 50 parts by mass or more and 200 parts by mass or less, based on the content of 100 parts by mass of the extreme pressure agent (D).

[0101] The water-soluble processing oil composition of this embodiment may contain one type of oiliness agent (E) alone, or it may contain two or more types.

[0102] Rust Inhibitor (F) The water-soluble machining oil composition of this embodiment preferably further contains a rust inhibitor (F). Examples of rust inhibitors (F) include polyhydroxy fatty acids, alkyl or alkenyl succinic acid derivatives, polyhydric alcohol partial esters, metal sulfonates, amines, and the like.

[0103] In the water-soluble processing oil composition of this embodiment, the rust inhibitor (F) is preferably a polyhydroxy fatty acid, and more preferably a dimer of 1,2-hydroxystearic acid, a trimer of 1,2-hydroxystearic acid, or a mixture of the dimer and trimer.

[0104] If the water-soluble machining oil composition of this embodiment contains a rust inhibitor (F), the amount of rust inhibitor (F) is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 15% by mass or more, based on the total amount of the water-soluble machining oil composition. Furthermore, the content of the rust inhibitor (F) is preferably 30% by mass or less, more preferably 25% by mass or less, and even more preferably 20% by mass or less, based on the total amount of the water-soluble processing oil composition. In one embodiment, the content of the rust inhibitor (F) is preferably 5% by mass or more and 30% by mass or less, more preferably 10% by mass or more and 25% by mass or less, and even more preferably 15% by mass or more and 20% by mass or less, based on the total amount of the water-soluble processing oil composition.

[0105] The water-soluble machining oil composition of this embodiment may contain one rust inhibitor (F) alone, or it may contain two or more rust inhibitors.

[0106] The water-soluble processing oil composition of this embodiment described above contains a base oil (A) and a silicone-based defoaming agent (B) that is modified by a polyalkylene oxide modified group and has a weight-average molecular weight of more than 26,000. The silicone-based defoaming agent (B) is modified with a polyalkylene oxide modifying group to enhance its hydrophilicity, while its weight-average molecular weight is controlled to over 26,000 to prevent excessive hydrophilicity. As a result, in its undiluted state, the silicone-based defoaming agent (B) disperses well in the base oil (A), and even when diluted with water for processing, the silicone-based defoaming agent (B) disperses well in both water and base oil (A). Therefore, the water-soluble processing oil composition of this embodiment maintains its foam-suppressing properties because the dispersibility of the silicone-based defoaming agent (B) is good whether it is in its undiluted state or diluted with water during processing.

[0107] In one embodiment of a water-soluble processing oil composition containing a base oil (A), a silicone-based defoaming agent (B), a surfactant (C), an extreme pressure agent (D), an oiliness agent (E), and water (W), foaming can be further suppressed while improving processability. In its undiluted state, the silicone-based defoamer (B) has moderate hydrophobicity, and therefore, for example, it has low affinity for water in micelle form. Consequently, it is presumed that no flocculation effect originating from water occurs, resulting in a moderate dispersion. When diluted with water for processing, the mixture forms an O / W (oil-in-water) emulsion with a small amount of oily component relative to the water. The silicone-based defoamer (B) has moderate hydrophobicity, so it is presumed to be easily incorporated into the microemulsion of oily components, resulting in a dispersed state in water. On the other hand, if, for example, the hydrophilicity of the silicone-based defoamer (B) is too high, the silicone-based defoamer (B) tends to aggregate near the interface between water and oily components. When the oily components form a microemulsion, they separate into those that are included in the oily components and those that are not, which is thought to worsen the dispersibility of the silicone-based defoamer (B) and reduce its defoaming ability.

[0108] The water-soluble machining fluid composition of this embodiment is useful for cutting or grinding metal workpieces. Specifically, the metal workpiece may include one or more metals selected from the group consisting of aluminum, aluminum alloys, copper, copper alloys, iron, and iron alloys. A specific example of an iron alloy is stainless steel.

[0109] (Metal processing method) The metalworking method of this embodiment comprises a dilution step of diluting the water-soluble processing oil composition of the above-described embodiment with water, and a processing step of performing metalworking using the diluted water-soluble processing oil composition.

[0110] [Dilution process] The dilution step is a step of diluting the water-soluble processing oil composition of the above-described embodiment with water. The water used in the dilution step may be the same as the water (W) in the water-soluble processing oil composition of the embodiment described above.

[0111] From the viewpoint of cooling properties, the dilution ratio of the water-soluble processing oil composition is preferably 5 times or more, more preferably 7 times or more, and even more preferably 10 times or more, in terms of volume relative to the water-soluble processing oil composition. Furthermore, from the viewpoint of processability, the dilution ratio of the water-soluble processing oil composition is preferably 50 times or less, more preferably 40 times or less, and even more preferably 30 times or less, in terms of volume relative to the water-soluble processing oil composition. In one embodiment, the dilution ratio of the water-soluble processing oil composition in the dilution step is preferably 5 to 50 times, more preferably 7 to 40 times, and even more preferably 10 to 30 times, in terms of volume relative to the water-soluble processing oil composition.

[0112] If the dilution ratio of the water-soluble machining oil composition in the dilution process is within the above preferred range, large changes in viscosity of the diluted water-soluble machining oil composition, reverse phase of the emulsion, etc., will not occur, and the concentration of each component of the water-soluble machining oil composition will be sufficient, resulting in more stable metalworking.

[0113] [Processing process] The processing step involves processing metal using the diluted water-soluble processing oil composition described above. Examples of such metals include aluminum, aluminum alloys, copper, copper alloys, iron, iron alloys, or metals containing two or more of these. A specific example of an iron alloy is stainless steel.

[0114] Examples of processing methods include cutting or grinding, and known devices can be used for cutting or grinding.

[0115] Since the metalworking method of this embodiment uses the water-soluble processing oil composition of the embodiment described above, foaming of the water-soluble processing oil composition during processing is suppressed, and stable metalworking can be performed. [Examples]

[0116] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples.

[0117] <Preparation of base oil (A)> Base oils (mineral oils) with the physical properties shown in Table 1 below were prepared. Note that "-" in Table 1 indicates that the value was below the detection limit.

[0118] [Measurement of kinematic viscosity at 40°C of base oil (A) and water-soluble processing oil composition] The kinematic viscosity (mm²) of base oil (A) at 40°C, measured in accordance with JIS K 2283:2000. 2 The kinematic viscosity (mm² / s) at 40°C for each example of the water-soluble machining oil composition is shown in Table 1. Similarly, the kinematic viscosity (mm² / s) for each example of the water-soluble machining oil composition at 40°C is shown in Table 1. 2 The values ​​for / s are shown in Tables 3-5.

[0119] [Table 1]

[0120] <Preparation of silicone-based defoaming agent> Silicone-based defoamers (B1) to (B12), (X1), and (X2) with the physical properties shown in Table 2 were prepared. (B1)~(B12): All are EOPO-modified dimethyl silicone. (X1): EOPO-modified dimethyl silicone (X2): Dimethyl silicone

[0121] [Measurement of weight-average molecular weight (Mw) of silicone-based defoamers] The weight-average molecular weight (Mw) of the silicone-based defoamers (B1) to (B12), (X1), and (X2) in polystyrene equivalents was determined by gel permeation chromatography (GPC) using the following measuring apparatus and conditions. The results are shown in Table 2. ≪Weight-average molecular weight (Mw) measuring device and measurement conditions≫ Equipment used: Shimadzu Corporation Prominence series Detector: RID-10A Column: Shodex KF-405LHQ Mobile phase: THF Flow rate: 0.5mL / min Concentration: 5,000mg / L Calibration material: Polystyrene

[0122] [Measurement of molecular weight of polyalkylene oxide modified groups in silicone-based defoamers] The molecular weights of the polyalkylene oxide modified groups of the silicone-based defoamers (B1) to (B12) and (X1) were calculated using the same method as described above. Furthermore, the polyalkylene oxide modified group of the silicone-based defoamers (B1) to (B12) and the silicone-based defoamer (X1) is a group represented by the following formula (x-0). Furthermore, for the peak area HaP attributed to the hydrogen atom Ha, an integral value of 0.4–0.5 ppm was used. For the peak area HcP attributed to hydrogen atoms (Hc), an integral value of 3.0–4.0 ppm was used. For the peak area HdP attributed to the hydrogen atom Hd, integral values ​​between 1.0 and 1.5 ppm were used.

[0123] [ka] [In the formula, pa represents the number of (-O-CH2CH2-) repeats. qa represents the number of (-O-CH2(CH3)CH-) repeats. * represents a bond.]

[0124] The molecular weight of the polyalkylene oxide modified group of silicone-based defoamers (B1) to (B12) and silicone-based defoamer (X1) was calculated using the following formula (1). Molecular weight of polyalkylene oxide modified group = number of pa repetitions × 44 + number of qa repetitions × 58 + 42 + 17 ... (1) The results are shown in Table 2.

[0125] [Measurement of the degradation rate of silicone-based defoamers] The polyalkylene oxide modification rates of silicone-based defoamers (B1) to (B12) and (X1) were calculated using the same method as described above. The constituent units of silicone-based defoamers (B1) to (B12) and silicone-based defoamer (X1) differ in the number of repetitions, but all are constituent units represented by the following formula (s-0). Furthermore, for the peak area HxP attributed to hydrogen atoms Hx, an integral value of 0.4 to 0.5 ppm was used. For the peak area HcP attributed to the hydrogen atom Hy, integral values ​​between -0.5 and 0.4 ppm were used.

[0126] [ka] [In the formula, X0 is the group represented by the above formula (x-0). m0 indicates the number of repetitions of the unmodified constituent unit [-(CH3)2SiO-]. n0 indicates the number of repetitions of the constituent unit modified by the group represented by the above formula (x-0).]

[0127] The modification rates of the polyalkylene oxide modified groups of the silicone-based defoamers (B1) to (B12) and (X1) were calculated using the following formula (2). Degeneration rate = n0 / (m0+n0) × 100 ... (2) The results are shown in Table 2.

[0128] [Table 2]

[0129] <Preparation of surfactant (C), extreme pressure agent (D), water (W), oiliness agent (E), and rust inhibitor (F)> The following surfactants (C), extreme pressure agents (D), water (W), oiliness agents (E), and rust inhibitors (F) were prepared. Surfactant (C1): Pluronic-type PAG (molecular weight 2650) Extreme pressure agent (D1): Oleic acid sulfide Water (W): Ion-exchanged water Oily agent (E1): Diisopropanolamine Rust inhibitor (F1): Mixture of 1,2-hydroxystearic acid dimers and trimers

[0130] <Manufacturing of water-soluble processed oil composition> The base oil (A), silicone-based defoaming agent (B), surfactant (C), extreme pressure agent (D), water (W), oiliness agent (E), and rust inhibitor (F) described above were mixed in the proportions shown in Tables 3 to 5 to produce the water-soluble machining oil compositions for each example.

[0131] [Foaming Test 1] (1) Each water-soluble processing oil composition prepared by the above method was diluted 10 times with deionized water to prepare samples for each example. (2) As shown in Figure 1, a 500 mL sample from each example was circulated in a 1000 mL graduated cylinder using a circulation pump P. The tip of the nozzle from which the sample from each example was ejected was positioned at the opening of the 1000 mL graduated cylinder. (3) After 20 minutes had elapsed since the start of circulation, the bubble height was read using the scale on the graduated cylinder, and the circulation pump P was stopped. (4) The foam height (mm) was calculated by subtracting the liquid level reading on the graduated cylinder before circulation was started from the foam height reading on the graduated cylinder obtained in (3). The results are shown in Tables 3 to 5.

[0132] [Foaming Test 2 (Stability Test)] (a) 20 L of each water-soluble processing oil composition prepared by the above method was left standing in a 20 L can at room temperature (25°C) for one month. (b) 100 mL was taken from the top of each water-soluble processing oil composition after it had been allowed to stand, and diluted 10 times with deionized water, and used as the sample. The foam height (mm) of each sample was determined using the same procedure as in (2) to (4) of [Foaming Test 1]. The results are shown in Tables 3 to 5.

[0133] [Table 3]

[0134] [Table 4]

[0135] [Table 5]

[0136] In Tables 3-5, the values ​​for base oil (A), defoamer, surfactant (C), extreme pressure agent (D), oiliness agent (E), and rust inhibitor (F) represent the content (mass%) relative to 100% of the total amount of the water-soluble processing oil composition.

[0137] As shown in Tables 3-5, the water-soluble processing oil compositions of the examples showed lower foaming heights in both foaming tests 1 and 2 compared to the water-soluble processing oil compositions of the comparative examples. In particular, the water-soluble processing oil compositions of the examples showed lower foaming heights in foaming test 2 compared to the water-soluble processing oil compositions of the comparative examples.

[0138] From the results of foaming test 1, it was confirmed that the water-soluble processing oil composition of the example exhibited good foam suppression when diluted with water. This is presumed to be due to the good dispersibility of the silicone-based defoaming agent (B) in the water-soluble processing oil composition of the example when diluted with water. Furthermore, the results of foaming test 2 confirmed that the water-soluble processing oil composition of the example could maintain its foaming suppression properties even after being left standing at room temperature (25°C) for one month. This is presumed to be because the silicone-based defoaming agent (B) in the water-soluble processing oil composition maintained good dispersibility even when the water-soluble processing oil composition of the example was stored in its undiluted state for a long period of time.

[0139] Among the water-soluble processing oil compositions of the examples, the water-soluble processing oil compositions of Examples 1 to 11 showed lower foaming heights in both foaming tests 1 and 2 compared to the water-soluble processing oil compositions of Examples 12 to 14.

[0140] In a comparison between the water-soluble processing oil compositions of Examples 1-11 and the water-soluble processing oil composition of Example 14, the silicone-based defoaming agent (B12) contained in the water-soluble processing oil composition of Example 14 had a lower modification rate (modification rate: 0.12%) compared to the other silicone-based defoaming agents (B). As a result, although the foam height in foaming test 1 was low, the foam height in foaming test 2 was higher than that of the water-soluble processing oil compositions of Examples 1-11. In other words, the water-soluble processing oil compositions of Examples 1-11 maintained their foam suppression properties for a longer period than the water-soluble processing oil composition of Example 14.

[0141] In a comparison between the water-soluble processing oil compositions of Examples 1-11 and the water-soluble processing oil composition of Example 13, the silicone-based defoaming agent (B11) contained in the water-soluble processing oil composition of Example 13 had a higher modification rate (modification rate: 2.38%) compared to the other silicone-based defoaming agents (B), resulting in higher foam heights in both foaming tests 1 and 2. In other words, the water-soluble processing oil compositions of Examples 1-11 exhibited better foam suppression than the water-soluble processing oil composition of Example 13, and maintained this foam suppression for a longer period.

[0142] In a comparison between the water-soluble processing oil compositions of Examples 1-11 and the water-soluble processing oil composition of Example 12, the silicone-based defoaming agent (B10) contained in the water-soluble processing oil composition of Example 12 had a lower molecular weight (Mw) of the polyalkylene oxide modified group (Molecular weight (Mw) of the modified group: 4580) compared to the other silicone-based defoaming agents (B), resulting in higher foam heights in both foaming tests 1 and 2. In other words, the water-soluble processing oil compositions of Examples 1-11 exhibited better foam suppression than the water-soluble processing oil composition of Example 12, and maintained this foam suppression for a longer period.

Claims

1. It contains a base oil (A) and a silicone-based defoaming agent (B) modified with a polyalkylene oxide modified group. The silicone-based defoaming agent (B) is a side-chain modified silicone-based defoaming agent represented by the following general formula (b-1), a double-ended modified silicone-based defoaming agent represented by the following general formula (b-2), a single-ended modified silicone-based defoaming agent represented by the following general formula (b-3), or a double-ended modified silicone-based defoaming agent represented by the following general formula (b-4). The weight-average molecular weight of the aforementioned silicone-based defoaming agent (B) is greater than 26,000. A water-soluble metalworking oil composition wherein the molecular weight of the polyalkylene oxide modified group in the silicone-based defoaming agent (B) is 5,000 or more and 10,000 or less. 【Chemistry 1】 [In the formula, X is independently a polyalkylene oxide modified group represented by the following general formula (X-1). m1 to m4 each independently represent the number of repetitions of the unmodified constituent unit [-(CH3)2SiO-]. n1 to n4 each independently represent the number of repetitions of the constituent unit modified by the polyalkylene oxide modification group. 【Chemistry 2】 [In the formula, R1 to R3 are each independently an alkylene group. p indicates the number of (-O-R2-) repeats. q indicates the number of (-O-R3-) repeats. * indicates a bond.]

2. The water-soluble metalworking oil composition according to claim 1, wherein the modification rate of the silicone-based defoaming agent (B) is greater than 0.12% and less than 2.38%.

3. Furthermore, the water-soluble metalworking oil composition according to claim 1 or 2 contains one or more surfactants selected from the group consisting of nonionic surfactants other than the silicone-based defoaming agent (B) and anionic surfactants.

4. The kinematic viscosity of the base oil (A) at 40°C is 10 mm ２ / s or more 100mm ２ A water-soluble metalworking oil composition according to any one of claims 1 to 3, wherein the value is less than or equal to / s.

5. A water-soluble metalworking oil composition according to any one of claims 1 to 4, used for cutting or grinding metal.

6. The water-soluble metalworking oil composition according to claim 5, wherein the metal comprises one or more metals selected from the group consisting of aluminum, aluminum alloys, copper, copper alloys, iron, and iron alloys.

7. A dilution step of diluting the water-soluble metalworking oil composition according to any one of claims 1 to 4 with water, A metalworking method comprising a processing step of processing a metal using the diluted water-soluble metalworking oil composition.

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