JPWO2020012792A1 - Water-soluble oil composition for metal processing - Google Patents

Abstract

An object of the present invention is to provide a water-soluble oil composition for metal processing containing alkanolamines, which is unlikely to cause a decrease in pH or a decrease in concentration. The water-soluble oil composition for metal processing according to the present invention contains a primary alkanolamine having a substituent that inhibits an intermolecular cyclization dehydration reaction. Here, the primary alkanolamine is represented by the following formula (I): [Chemical formula 1] (R1, R2, R3 and R4 are hydrogens, or alkyl groups having the same or different carbon atoms 1 to 6 or 3 to 6 carbon atoms, respectively. R1 and R2 are both alkyl groups with 1 to 6 carbon atoms or cycloalkyl groups with 3 to 6 carbon atoms, and / or R3 and R4 are both alkyl groups with 1 to 6 carbon atoms. It is a group or a cycloalkyl group having 3 to 6 carbon atoms.).

Description

The present invention relates to a water-soluble oil composition for metal processing. More specifically, the present invention relates to an oil composition which is used for metal cutting, grinding, plastic working, precision polishing and the like and has antiseptic and rust preventive effects on metal surfaces.

Oil-based compositions have been used as oil-based compositions for metal processing such as cutting and grinding, but water-soluble oil-based compositions are widely used from the viewpoint of suppressing the risk of fire and improving workability. It is designed to be used. The water-soluble oil composition is a mixture containing a lubricating oil, an oil agent, an anti-wear agent, an extreme pressure additive, a rust preventive, a surfactant and the like as constituents. In particular, alkanolamines such as monoethanolamine, diethanolamine, and triethanolamine are blended for the purpose of preventing rust and maintaining the pH of the oil composition.

International Publication No. 2014/12499 discloses an aqueous metalworking oil containing two types of alkanolamines having a predetermined structure. Further, Japanese Patent Application Laid-Open No. 2002-338988 discloses a water-soluble cutting and grinding oil for alloys containing a dibasic acid, a mineral oil and / or a fat and oil, an alkali metal compound and / or an amine, and a surfactant.

Monoisopropanolamine (MIPA), which is mentioned as an example of alkanolamines contained in metal processing oils in the above literature, is an alkaline substance and forms an amine salt with a fatty acid to exert a surface-active effect. , Is often used as an alkanolamine component of metal processing oils. However, when the metalworking oil containing MIPA is continuously used, there is a problem that the pH deteriorates over time and the pH decreases. The metalworking oil is normally circulated and used continuously while adding a new metalworking oil, but the pH does not rise or the concentration of MIPA does not rise even if the new metalworking oil is added. was there. This is because when the metal processing oil is exposed to the frictional heat between the tool and the processing material generated during metal processing, the two MIPA molecules contained in the metal processing oil undergo an intermolecular cyclization dehydration reaction to form dimethylpyrazine. It is presumed that this is because MIPA gradually decreases due to its formation. Therefore, an object of the present invention is to provide a water-soluble oil composition for metal processing containing alkanolamines, which is unlikely to cause a decrease in pH or a decrease in concentration.

The water-soluble oil composition for metal processing according to the embodiment of the present invention is characterized by containing a primary alkanolamine having a substituent that inhibits an intermolecular cyclization dehydration reaction.

In the water-soluble oil composition for metal processing of the present invention, pyrazines are not produced due to an increase in temperature during metal processing, the concentration of an alkanolamine component is not decreased, or the pH of the oil composition is not decreased. It can be used stably and continuously without deterioration for a long period of time.

FIG. 1 shows an oil composition before use (Product A containing 2-amino-2-methyl-1-propanol (AMP)), after 5 months of use, after 5 months of use, and after 11 months of use. It is also a GC-MS spectrum of the oil composition after 8 months of use. FIG. 2 is a GC-MS spectrum of an oil composition before use (product B containing monoisopropanolamine (MIPA)) and an oil composition after use for one month.

Embodiments of the present invention will be described below. An embodiment of the present invention is a water-soluble oil composition for metal processing containing a primary alkanolamine having a substituent that inhibits an intermolecular cyclization dehydration reaction. In the present embodiment, the oil composition is a mixture containing an oil component. Generally, an oil composition contains a natural oil such as mineral oil and a synthetic oil such as polyalkylene glycol as a lubricant, and also an oily agent, an anti-wear agent, an extreme pressure additive, a rust preventive, an antiseptic, and a surfactant. Contains an activator or the like as a constituent component. Water-soluble means that it is easily dissolved in water and has a high affinity with water. The water-soluble oil composition is in the form of an emulsion, a transparent aqueous solution, or a translucent soluble aqueous solution, which can be diluted with water and used. Metal processing means cutting, grinding, plastic working, rolling, etc. of metal. The water-soluble oil composition for metal processing is required to have an effect of maintaining the lubricity of the metal surface, cooling the metal surface, and preventing rusting of the metal surface during these operations. The intermolecular cyclization dehydration reaction in this embodiment will be described later.

（Ｒ_１、Ｒ_２、Ｒ_３およびＲ_４は水素、または各々同一のまたは異なる炭素数１〜６のアルキル基または炭素数３〜６のシクロアルキル基であり、ここでＲ_１およびＲ_２はともに炭素数１〜６のアルキル基または炭素数３〜６のシクロアルキル基であり、および／またはＲ_３およびＲ_４はともに炭素数１〜６のアルキル基または炭素数３〜６のシクロアルキル基である。）で表される。式（Ｉ）中、アミノ基（−ＮＨ_２）または水酸基（−ＯＨ）に隣接する炭素の少なくとも一方に、２つのアルキル基が存在している。先に述べたとおり、金属加工油剤には従来からアルカノールアミンとしてモノイソプロパノールアミン（ＭＩＰＡ）が添加されていた。ＭＩＰＡは、金属加工時の高温条件と金属との接触の下で、以下：

のように反応し、ジメチルピラジンを形成する場合があった。このように、１級アルカノールアミン２分子が分子間で脱水しながら環を形成する反応を、本明細書では分子間環化脱水反応と称するものとする。金属加工油剤を長期にわたり使用すると、上記の分子間環化脱水反応によりジメチルピラジンが生成し、ＭＩＰＡは漸次減少していき、これに伴い金属加工油剤のｐＨが低下していくことがあった。In an embodiment, the primary alkanolamine is represented by the following formula (I):

(R ₁ , R ₂ , R ₃ and R ₄ are hydrogens, or alkyl groups having the same or different carbon atoms 1 to 6 or cycloalkyl groups having 3 to 6 carbon atoms, respectively, where R ₁ and R ₂ are. Both are alkyl groups with 1 to 6 carbon atoms or cycloalkyl groups with 3 to 6 carbon atoms, and / or R ₃ and R ₄ are both alkyl groups with 1 to 6 carbon atoms or cycloalkyl groups with 3 to 6 carbon atoms. Is represented by.). In formula (I), two alkyl groups are present on at least one of the carbons adjacent to _{the amino group (-NH 2) or the hydroxyl group (-OH).} As described above, monoisopropanolamine (MIPA) has been conventionally added as an alkanolamine to the metalworking oil. MIPA is used under high temperature conditions during metal processing and in contact with metal:

In some cases, it reacted as follows to form dimethylpyrazine. Such a reaction in which two primary alkanolamine molecules form a ring while dehydrating between molecules is referred to as an intermolecular cyclization dehydration reaction in the present specification. When the metalworking oil was used for a long period of time, dimethylpyrazine was produced by the above intermolecular cyclization dehydration reaction, and MIPA gradually decreased, and the pH of the metalworking oil may decrease accordingly.

The primary alkanolamines of the formula (I) used in the present embodiment, R ₁ , R ₂ , R ₃ and R _4, are hydrogen, or an alkyl group having the same or different carbon atoms 1 to 6, or an alkyl group having 3 to 6 carbon atoms, respectively. It is a cycloalkyl group of 6. Alkyl groups having 1 to 6 carbon atoms may be linear or branched. The cycloalkyl group having 3 to 6 carbon atoms is a cyclic alkyl group such as a cyclopropyl group, a cyclobutyl group, a cyclopentyl group or a cyclohexyl group. The substituents R ₁ , R ₂ , R ₃ and R ₄ are such that R ₁ and R ₂ are both alkyl groups having 1 to 6 carbon atoms or cycloalkyl groups having 3 to 6 carbon atoms, and R ₃ and R ₄ satisfies at least one of being an alkyl group having 1 to 6 carbon atoms or a cycloalkyl group having 3 to 6 carbon atoms. Therefore, substituents between the two alkanolamine molecule R ₁ and R ₂ and / or R ₃ and R ₄ is an obstacle, less prone to intermolecular cyclization dehydration reaction. In the oil composition of the embodiment, the formation of pyrazines is unlikely to occur even after long-term use, the concentration of the alkanolamine component is unlikely to decrease, and therefore the pH is unlikely to decrease. Here, the pyrazines refer to pyrazine and pyrazine having a substituent. Suitable groups as substituents R ₁ , R ₂ , R ₃ and R ₄ are alkyl groups having 1 to 6 carbon atoms, preferably alkyl groups having 1 to 3 carbon atoms, or cycloalkyl groups having 3 to 6 carbon atoms. is there. As the number of carbon atoms in the alkyl group or cycloalkyl group increases, the steric hindrance between the two alkanolamine molecules increases, and it is considered that the intermolecular cyclization dehydration reaction can be more effectively inhibited. However, if the number of carbon atoms of the alkyl group or the cycloalkyl group becomes too large, the water solubility of the alkanolamine itself decreases, so that it cannot be used as a component of the water-soluble oil composition of the present embodiment. Therefore, the substituents R ₁ , R ₂ , R ₃ and R ₄ are particularly preferably alkyl groups having 1 to 3 carbon atoms. And maintenance of water-soluble alkanolamines, both in terms of suppressing the generation reaction of pyrazines, particularly suitable groups as substituents R _1, R _2, R ₃ and R ₄ are alkyl groups having 1 or 2 carbon atoms That is, a methyl group or an ethyl group.

In embodiments, the primary alkanolamines of formula (I) include, for example, 2-amino-2-methyl-1-propanol, 1-amino-2-methyl-2-propanol, 3-amino-3-methyl-. 2-butanol, 3-amino-2-methyl-2-butanol, 3-amino-2,3-dimethyl-2-butanol, 2-amino-2-ethyl-1-propanol, 1-amino-2-ethyl- 2-Propanol can be mentioned.

In the embodiment, the primary alkanolamine is added to the water-soluble oil composition for metal processing in order to impart rust prevention and antiseptic properties to the metal surface. For this purpose, the primary alkanolamine can be added in a proportion of 1 to 20%, preferably 2 to 15% based on the weight of the water-soluble oil composition for metal processing. The primary alkanolamine can be used alone or in admixture of two or more. When two or more kinds of primary alkanolamines are mixed and used, the total amount of the mixed primary alkanolamines is preferably 1 to 20% based on the weight of the water-soluble oil composition for metal processing.

In addition to the above-mentioned primary alkanolamine, the water-soluble oil composition for metal processing of the embodiment includes water, mineral oil, animal and vegetable oil, hydrocarbon-based synthetic oil, fatty acid, fatty acid condensate, fatty acid ester, organic amine, and surfactant. Additives such as agents, anti-wear agents, extreme pressure additives, rust inhibitors, preservatives, and antifoaming agents can be blended.

Mineral oil is a mixture of hydrocarbon compounds derived from petroleum, natural gas and the like. For example, paraffin oil or naphthenic oil can be used. Mineral oil is used as a base oil for a water-soluble oil composition for metal processing. If desired, two or more of the above mineral oils can be used in combination.

As the animal and vegetable oils, vegetable oils such as castor oil, rapeseed oil, palm oil, soybean oil and olive oil, and animal oils such as beef tallow, sheep fat, pork fat and fish oil can be used. Animal and vegetable oils are used as base oils for water-soluble oil composition for metal processing. Two or more of the above animal and vegetable oils can be used in combination as desired.

As the hydrocarbon-based synthetic oil, synthetic hydrocarbon oil typified by α-polyolefin, polybutene or the like, ether-based synthetic oil typified by alkyldiphenyl ether, polypropylene glycol or the like, silicon oil, fluorine oil or the like can be used. If desired, two or more of the above hydrocarbon-based synthetic oils can be used in combination as appropriate.

Fatty acids are long-chain hydrocarbon carboxylic acids. The fatty acid condensate is an intermolecular dehydration condensate of fatty acids, and the fatty acid ester is an ester compound of a fatty acid and an alcohol. Fatty acids, fatty acid condensates, and fatty acid esters are added as rust inhibitors and lubricants in water-soluble oil composition for metal processing. Fatty acids preferably used in the water-soluble oil composition for metal processing include butyric acid, valeric acid, caprylic acid, palmitic acid, stearic acid, oleic acid, linoleic acid, arachidic acid and the like, and these condensates are fatty acid condensates. Can be used as. On the other hand, fatty acid esters preferably used in the water-soluble oil composition for metal processing are lauric acid methyl ester, stearic acid methyl ester, oleic acid methyl ester, Himashi fatty acid methyl ester, palmitate butyl ester, stearate octyl ester, and isopropyl myristate. Examples thereof include esters and trimethylolpropane caprylic acid esters. Two or more of the above fatty acids, fatty acid condensates and fatty acid esters can be appropriately used in combination depending on the intended use and desired function.

Similar to the primary alkanolamine, the organic amine is added to the water-soluble oil composition for metal processing in order to impart rust prevention and antiseptic properties to the metal surface. Amines preferably used in the water-soluble oil composition for metal processing are alkylamines having 1 to 5 carbon atoms such as ethylamine and propylamine, cycloalkylamines having 5 to 20 carbon atoms such as morpholine and cyclohexylamine, and diethanolamine. Examples thereof include tertiary alkanolamines such as tertiary alkanolamines and triethanolamines. Two or more kinds of organic amines can be appropriately used in combination depending on the intended use and desired function.

Surfactants are added to maintain the water-soluble oil composition for metalworking as a stable composition. As the surfactant, any of a cationic surfactant, an anionic surfactant, a nonionic surfactant, and an amphoteric surfactant can be used. Examples of suitable cationic surfactants include quaternary ammonium salts. Examples of suitable anionic surfactants include alkyl group-containing sulfonates, alkyl group-containing sulfonic acid esters, alkyl group-containing phosphates, alkyl group-containing phosphoric acid esters, organic fatty acids and organic fatty acid derivatives, and alkyl groups. Containing sulfonates, organic fatty acids and organic fatty acid derivatives are particularly preferred. Suitable nonionic surfactants include alkylalcohol-ethylene oxide adducts, terminal alkyl ethers of alkylalcohol-ethylene oxide adducts, organic fatty acids-ethylene oxide adducts, hydroxy fatty acids-ethylene oxide adducts, pluronic surfactants, and te. Examples thereof include tronic surfactants and sugar ester-ethylene oxide adducts. Examples of suitable amphoteric surfactants include alkyl betaines. Two or more of the above-mentioned surfactants can be appropriately used in combination depending on the intended use and desired function.

Anti-wear agents are added to prevent friction between the two sides of the metal, wear, and seizure. Suitable used as anti-wear agents include, for example, phosphate esters (tricresyl phosphate, lauryl acid phosphate, etc.), subphosphate esters (tributyl phosphate, dilauryl phosphate, etc.), thiophosphates (dialkyl dithiophosphate, etc.). (Zinc acid acid, zinc diallyl dithiophosphate, etc.), phosphate ester amine salt, zinc dialkyl dithiocarbamate, etc. can be mentioned. Two or more of the above anti-wear agents can be used in combination as desired.

Extreme pressure additives are added to prevent friction, wear and seizure between the two sides of the metal. Extreme pressure additives include, for example, sulfide fats and oils (such as sulfide palm oil), sulfide esters (such as sulfide fat esters), sulfides (dibenzyldisulfide, alkylpolysulfide, olefinpolysulfide, zantic sulfide, etc.), chlorine compounds (chlorinated). Paraffin, methyltrichlorostearate, etc.), lead naphthenate, amine alkylthiophosphate, chloroalkylzantate, etc. Two or more of the above extreme pressure additives can be used in combination as desired.

A rust inhibitor is added to suppress the formation of rust on the metal surface. As rust preventives, calcium sulfonate, calcium phenate, calcium salicylate, magnesium sulfonate, magnesium phenate, magnesium salicylate, barium sulfonate, barium phenate, barium salicylate, glycerin monoolate, glycerin monolaurate, glycerin monostearate, sorbitan Monoolate, sorbitan monolaurate, sorbitan monostearate and the like can be used. Two or more of the above rust preventives can be used in combination as desired.

Preservatives are added to prevent the growth of microorganisms, especially in water-soluble oil compositions. As preservatives, thiazoles such as 2-methyl-4-isothiazolin-3-one, 1,2-benzoisothiazolin-3-one, 5-chloro-2-methyl-4-isothiazolin-3-one, 3-iodo Iode-based such as -2-propagilbutylcarbamic acid, phenol-based such as o-phenyl-phenol, p-chloro-m-cresol, 3-methyl-4-chloro-phenol, 2-pyridinethiol-1-oxide sodium Pyridine-based such as hexahydro-1,3,5-tris (2-hydroxyethyl) -S-triazine, triazine-based such as hexahydro-1,3,5-triethyl-S-triazine, 1,2-dibromo-2 , Brom-based such as 4-dicyanobutane, 2-bromo-2-nitropropane, inorganic-based such as water-soluble glass-silver, zeolite-copper, poly {oxyethylene (dimethylimino) ethylene (dimethylimino) ethylene} dichloride, 5-Methyloxazolidine, 4- (2-nitrobutyl) morpholine, tris (hydroxymethyl) nitromethane, 4,4'-(2-ethyl-2-nitrotrimethylene) dimorpholine, boric acid and the like can be used. Two or more of the above preservatives can be used in combination as desired.

The defoaming agent is added to prevent foaming due to the surfactant contained in the oil composition. Examples of the defoaming agent include organic defoaming agents such as silicone-based defoaming agents, polyols, and higher alcohols. Two or more of the above antifoaming agents can be used in combination as desired.

In addition to these components, non-ferrous metal anticorrosive agents, organic acids, alcohols, chelating agents, colorants, fragrances and the like can be appropriately added to the water-soluble oil composition for metal processing of the embodiment.

The water-soluble oil composition for metal processing of the embodiment can be obtained by mixing these components in an appropriate ratio. Each component may be blended in a proportion well known to those skilled in the art according to a conventionally used metal processing oil. Each component of the water-soluble oil composition for metal processing of the embodiment has an effect of suppressing the intermolecular cyclization dehydration reaction of the primary alkanolamine, an effect of suppressing the production of pyrazines, and an effect of suppressing a decrease in pH of the oil composition. It is formulated so as not to interfere with it.

このため、実施形態の油剤組成物は、金属加工用途に長期にわたり使用しても、ピラジン類の生成が抑制される。The oil composition of the embodiment containing the primary alkanolamine is characterized in that the production of pyrazines due to the intermolecular cyclization dehydration reaction of the primary alkanolamine is suppressed. Here, the formation of pyrazines by the intermolecular cyclization dehydration reaction of the primary alkanolamine means that the amino group of the primary alkanolamine molecule and the hydroxyl group of another primary alkanolamine molecule undergo a dehydration reaction between the molecules to form a ring structure. It refers to the condensation of two alkanolamines to form pyrazines so as to form. Pyrazines refer to pyrazines and pyrazines having substituents. Even if two molecules of the primary alkanolamine used in the embodiment are close to each other, the substituents R ₁ and R ₂ are both an alkyl group having 1 to 6 carbon atoms or a cycloalkyl group having 3 to 6 carbon atoms, and / or Since _{both R 3} and R ₄ are alkyl groups having 1 to 6 carbon atoms or cycloalkyl groups having 3 to 6 carbon atoms, the substituents R ₁ and R ₂ and / or R ₃ and R ₄ become obstacles and are intermolecular. Less likely to cause cyclization dehydration reaction.

Therefore, the oil composition of the embodiment suppresses the production of pyrazines even when used for a long period of time in metal processing applications.

The oil composition of the embodiment containing the primary alkanolamine is characterized in that the decrease in the concentration of the primary alkanolamine with use is suppressed. Here, the decrease in the concentration of the primary alkanolamine means that the primary alkanolamine is changed to a compound different from the primary alkanolamine, and the concentration of the primary alkanolamine itself is lowered. When the oil composition of the embodiment is used for metal processing for a long period of time, it is exposed to harsh conditions such as high heat and high shear, and the primary alkanolamine causes a decomposition reaction or the like, or, for example, described above. Two primary alkanolamine molecules may condense with each other, as in the intermolecular cyclization dehydration reaction of monoisopropanolamine (MIPA). The primary alkanolamine used in the oil composition of the present embodiment is an alkyl group having 1 to 6 carbon atoms or a cycloalkyl group having 3 to 6 carbon atoms in which _{the substituents R 1} and R _{2 are both, and /.} Alternatively, since both R ₃ and R ₄ are characterized by being an alkyl group having 1 to 6 carbon atoms or a cycloalkyl group having 3 to 6 carbon atoms, such a condensation reaction is unlikely to occur. Therefore, in the oil composition of the embodiment, the decrease in the concentration of the primary alkanolamine with use is suppressed.

(1) Examination of components of oil composition before and after use 1
An oil composition containing 2-amino-2-methyl-1-propanol (AMP), which is a primary alkanolamine, as an alkanolamine, and an oil composition containing a conventionally used monoisopropanolamine (MIPA). Was used for a long period of time for metal processing, and it was examined whether the constituents changed before and after use.

(1-1) Example 1
An oil composition (Product A, Neos Co., Ltd.) containing 3.6% of AMP as an alkanolamine was used for metal processing for 5 to 11 months. GC-MS measurement was performed before and after use of this oil composition, and the constituents were analyzed. The GC-MS measuring device was JMS-Q1050GV (JEOL Ltd.), the column used for the measurement was CP-Volamine (Aglian Technology), and the diluting solvent was ion-exchanged water or methanol. Dilution was performed at an arbitrary magnification depending on the measurement sample. The conditions for GC-MS measurement are shown in Table 1 below.

FIG. 1 shows the GC-MS of the oil composition (new liquid) before use and each oil composition after 5 months of use, 5 months of use, 11 months of use, and 8 months of use. The spectrum is shown. In FIG. 1, No. 1: GC-MS spectrum of product A new solution, No. 2: GC-MS spectrum of product A after use at company S for about 5 months, No. 3: GC-MS spectrum of product A after use at NS for about 5 months, No. 4: GC-MS spectrum of product A after use at company N for about 11 months, No. 5: GC-MS spectrum of product A after being used by company D for about 8 months.

(1-2) Comparative Example 1
An oil composition containing 2.0% MIPA as an alkanolamine (Product B, Neos Co., Ltd.) was used for metal processing for one month. For each of the oil composition before and after use, GC-MS measurement was performed under the same conditions as in Example 1, and the constituent components were analyzed. FIG. 2 shows the GC-MS spectra of the oil composition (new liquid) before use and each oil composition after use for one month. In FIG. 2, No. 1: GC-MS spectrum of product B new liquid, No. 2: GC-MS spectrum of product B after being used by Company M for about 1 month.
The components of the oil composition used in Example 1 and Comparative Example 1 are shown in Table 2 below.

In FIG. 1 (Example 1), no change in the constituent components of the oil composition before and after use is observed. However, in FIG. 2 (Comparative Example 1), a peak based on a new component (peak in FIG. 2 spectrum No. 2 near 16 minutes) was observed in the spectrum of the oil composition after use, which was not found in the new solution. .. When the component belonging to this peak was identified by mass spectrometry (MS), it was found to be 2,5-dimethylpyrazine.

The oil composition of the present invention does not produce pyrazines due to the intermolecular cyclization-dehydration reaction of alkanolamines even when used for a long period of time at high temperature. As a result, it can be said that a decrease in the concentration of alkanolamine and a decrease in the pH of the oil composition are unlikely to occur. On the other hand, when the oil composition of the comparative example is used for a long period of time at a high temperature, alkanolamine (MIPA) undergoes an intermolecular cyclization dehydration reaction to produce pyrazines, so that the alkanolamine gradually decreases, and the oil composition May lower the pH of.

(2) Examination of the components of the oil composition before and after use 2
As alkanolamine, an oil composition containing 2-amino-2-methyl-1-propanol (AMP), which is a primary alkanolamine, and an oil composition containing monoisopropanolamine (MIPA) are metal-processed, respectively. It was used for a long period of time, and it was examined whether the constituents changed before and after use.

(2-1) Example 2
Of AMP, which is a primary alkanolamine, triethanolamine (TEA), which is a tertiary alkanolamine, and N, N-bis (2-hydroxyethyl) -N-cyclohexylamine (CH-020), which is a tertiary alkanolamine. Product A (Neos Co., Ltd., AMP: 3.6%, TEA: 2.0%) and Product C (Neos Co., Ltd., AMP: 1.8%, CH-020:) containing at least two of the above. 2.0%) was used for metal processing applications for 1 to 5 months. Capillary electrophoresis analysis (CE) was performed on each of these oil compositions before and after use. The CE measuring device was G1600A (Agrient Technologies), the column used for the measurement was G1600-61232 (Aglian Technologies, 50 μm I.D. × 56 cm), and the diluting solvent was ion-exchanged water. Dilution was performed at an arbitrary magnification depending on the measurement sample. The conditions for CE measurement are shown in Table 3 below.

Table 4 below shows the ratio of the AMP concentration to the tertiary alkanolamine concentration in each oil composition (new liquid) before use and each oil composition after 1 to 6 months of use, which was calculated by CE measurement. Shown.

(2-2) Comparative Example 2
Of MIPA, which is a primary alkanolamine, triethanolamine (TEA), which is a tertiary alkanolamine, and N, N-bis (2-hydroxyethyl) -N-cyclohexylamine (CH-020), which is a tertiary amine. Oil composition product D (Neos Co., Ltd., MIPA: 3.0%, TEA 4.0%) and product B (Neos Co., Ltd., MIPA: 2.0%, TEA: 2.0%) containing at least two kinds. Used for 1 to 3 months for metal processing. CE measurement was performed under the same conditions as in Example 2 before and after using this oil composition. Table 5 below shows the ratio of the MIPA concentration to the tertiary alkanolamine concentration in each of the oil composition (new liquid) before use and each oil composition after use for 1 to 6 months, which was calculated by CE measurement. Shown.
The components of the oil composition used in Example 2 and Comparative Example 2 are shown in Table 2.

The oil composition of the present invention containing AMP shows almost no change in the concentration of AMP even after long-term use. Since the concentration of other amines (TEA, CH-020) does not change in the oil composition of the present invention even after long-term use, it is presumed that there is almost no decrease in the pH of the oil composition. On the other hand, it can be seen that the MIPA concentration of the comparative oil composition containing MIPA decreases after long-term use. It is presumed that the pH of the oil composition is also lowered accordingly.

Claims (4)

A water-soluble oil composition for metal processing containing a primary alkanolamine having a substituent that inhibits an intermolecular cyclization dehydration reaction. The primary alkanolamine is based on the following formula (I):

(R ₁ , R ₂ , R ₃ and R ₄ are hydrogens, or alkyl groups having the same or different carbon atoms 1 to 6 or cycloalkyl groups having 3 to 6 carbon atoms, respectively, where R ₁ and R ₂ are. Both are alkyl groups with 1 to 6 carbon atoms or cycloalkyl groups with 3 to 6 carbon atoms, and / or R ₃ and R ₄ are both alkyl groups with 1 to 6 carbon atoms or cycloalkyl groups with 3 to 6 carbon atoms. Is.)
The water-soluble oil composition for metal processing according to claim 1. The water for metal processing according to claim 1 or 2, wherein the production of pyrazines due to the intermolecular cyclization dehydration reaction of the primary alkanolamine accompanying the use of the water-soluble oil composition for metal processing is suppressed. Soluble oil composition. The water-soluble oil composition for metal processing according to any one of claims 1 to 3, wherein a decrease in the concentration of the primary alkanolamine accompanying the use of the water-soluble oil composition for metal processing is suppressed.

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