JP6984402B2 - Metalworking oil Base oil, its manufacturing method and metalworking oil - Google Patents

Description

The present invention relates to an ester-based metalworking oil base oil. More specifically, the present invention has a high ignition point, excellent low-temperature fluidity, and low viscosity, and is suitably used for metalworking oils such as lubricating oils. It relates to a metalworking oil base oil and a method for producing the same.

Conventionally, cheap and easily available mineral oil has been mainly used for metal processing oil such as lubricating oil, but since the balance of various physical properties such as heat resistance is poor, molecular design according to the purpose has been performed in recent years. Synthetic processing oils such as synthetic hydrocarbons and organic acid esters capable of this have come to be mainly used.

Examples of the organic acid esters include esters obtained from the reaction of aliphatic monocarboxylic acids with monohydric alcohols, polyhydric alcohols, polybasic acids, composite esters obtained from reactions with aliphatic monocarboxylic acids, or Metal processing oil base oils and the like using aliphatic polyoxyalkylene alkyl ethers have been proposed (see, for example, Patent Documents 1 to 3).

However, the compounds provided in these documents have a trade-off relationship between a high flash point and low temperature fluidity, that is, a compound having a high flash point and good safety is inferior in low temperature fluidity and has excellent low temperature flowability. Compounds with a flash point have a low flash point, and many of them fall under the dangerous goods Class 4 Class 3 petroleum (flash point 70 ° C or higher and lower than 200 ° C) under the Fire Service Act of Japan. Since there is an advantage of excellent low temperature fluidity, that is, the lower the pour point, the wider the operating temperature range, there is a demand for the development of a compound (base oil) capable of achieving both low temperature fluidity and a high flash point. Further, from the viewpoint of energy saving, a low-viscosity base oil is required for the purpose of suppressing friction loss during use.

Japanese Unexamined Patent Publication No. 2005-146210 Special Table No. 7-508783 International Publication No. 2012/0088442

In view of the above circumstances, the problem to be solved by the present invention is suitable as a base oil for synthetic oils used in the processing of metals such as lubricating oils, which have both high ignition point and low temperature fluidity and low viscosity. It is an object of the present invention to provide a metalworking oil base oil that can be used in the above, a method for producing the same, and a metalworking oil containing the same.

As a result of diligent studies, the present inventors have found that the above problems can be solved by using a diester compound having a specific structure as a base oil, and have completed the present invention.

That is, the present invention has the following general formula (1).

（式中、Ｒ^１、Ｒ^２はそれぞれ独立に炭素原子数３〜２９の脂肪族炭化水素基であり、Ｒ^３は水素原子又はメチル基であり、Ｒ^４は炭素原子数１〜２４の脂肪族飽和炭化水素基である。）
で表されることを特徴とする金属加工油基油、その製造方法及びこれを含む金属加工油を提供するものである。

(In the formula, R ¹ and R ² are independently aliphatic hydrocarbon groups having 3 to 29 carbon atoms, R ³ is a hydrogen atom or a methyl group, and R ⁴ is a fat having 1 to 24 carbon atoms. It is a group saturated hydrocarbon group.)
The present invention provides a metalworking oil base oil represented by, a method for producing the same, and a metalworking oil containing the same.

According to the present invention, it is possible to provide a metalworking oil base oil which has an excellent balance between a high ignition point, low temperature fluidity and a low viscosity when used as a metalworking oil and can be suitably used as a lubricant or the like. .. Further, the metal processing oil base oil is a diester compound having a specific structure, but in the production method thereof, the reaction proceeds stoichiometrically at a relatively low temperature, so that the content of by-products can be suppressed to an extremely low level. At the same time, it is possible to prevent coloring of the product because it is a low temperature reaction. In addition, it has excellent compatibility with other additives such as extreme pressure additives when adjusting as metal processing oil, and has good lubricity, so it is the main component of lubricants used during metal processing. Can be suitably used as.

The metalworking oil base oil of the present invention has the following general formula (1).

（式中、Ｒ^１、Ｒ^２はそれぞれ独立に炭素原子数３〜２９の脂肪族炭化水素基であり、Ｒ^３は水素原子又はメチル基であり、Ｒ^４は炭素原子数１〜２４の脂肪族飽和炭化水素基である。）
で表されることを特徴とする。

(In the formula, R ¹ and R ² are independently aliphatic hydrocarbon groups having 3 to 29 carbon atoms, R ³ is a hydrogen atom or a methyl group, and R ⁴ is a fat having 1 to 24 carbon atoms. It is a group saturated hydrocarbon group.)
It is characterized by being represented by.

The compound represented by the general formula (1) is a diester compound, but the number of carbon atoms between the carbonyloxy groups is 2, and the substituent (R ³ ) bonded to one of them is hydrogen. It is an atom or a methyl group, and the substituent (R ⁴ ) bonded to the other carbon atom is characterized by being an aliphatic saturated hydrocarbon group having 1 to 24 carbon atoms. It realizes "high flammability", "low temperature fluidity", and "low viscosity" suitable for processing oil base oil. Furthermore, since it has a diester structure and has an appropriate balance between polar groups and non-polar groups (hydrocarbon groups), it is also excellent in compatibility with various additives used when preparing as a metalworking oil. become.

The metalworking oil base oil of the present invention is a diester compound having such a specific structure, but even if it is composed of a single compound, it is a mixture composed of a plurality of compounds represented by the general formula (1). May be there.

^{R 1} and R ² in the general formula (1) are independently aliphatic hydrocarbon groups having 3 to 29 carbon atoms, and even if they are linear, they contain one or more branched structures. Further, the carbon atom-carbon atom bond may be partially unsaturated. ^{Among these, R 1} and R ² are independently carbons from the viewpoint of easily balancing high ignition point, low temperature fluidity, and low viscosity, and from the viewpoint of easy availability of raw materials by the manufacturing method described later. It is preferably an aliphatic saturated hydrocarbon group having 4 to 17 atoms, and more preferably a heptyl group, an octyl group, a nonyl group or the like. Further, from the viewpoint of the manufacturing method, it is more preferable that ^{R 1} and R ^{2 have the same structure.}

^{Further, R 3} in the general formula (1) is a hydrogen atom or a methyl group, which has a structure associated with the opening of the ring of the olefin oxide (a1) used as a raw material in the production method described later, and the raw material is easily available. From the viewpoint of sex, a hydrogen atom is more preferable.

Moreover, the generally formula (1) R ⁴ in the aliphatic saturated hydrocarbon group having 1 to 24 carbon atoms, particularly high flash point and low temperature fluidity, from the viewpoint of easily tuning the low viscosity, carbon atoms It is preferably an aliphatic saturated hydrocarbon group having a number of 10 to 24. Further, although the hydrocarbon group may have a branched structure, it is preferably linear from the viewpoint of being more excellent in compatibility with other additives when prepared as a metalworking oil. From this point of view, preferable R ⁴ is a dodecyl group, tetradecyl group, hexadecyl group, an octadecyl group or the like.

The metalworking oil base oil of the present invention preferably has a number average molecular weight in the range of 1000 to 3000 and an acid value in the range of 1000 to 3000 from the viewpoint of excellent balance of high ignition point, low temperature fluidity and low viscosity. It is more preferably 0.5 or less and the hydroxyl value is 1.0 or less.

The GPC measurement in the present invention was carried out under the following conditions.
[GPC measurement conditions]
Measuring device: High-speed GPC device "HLC-8320GPC" manufactured by Tosoh Corporation
Column: "TSK GURDCOLUMN SuperHZ-L" manufactured by Tosoh Corporation + "TSK gel SuperHZM-M" manufactured by Tosoh Corporation + "TSK gel SuperHZM-M" manufactured by Tosoh Corporation + "TSK gel SuperHZ-2000" manufactured by Tosoh Corporation "TSK gel SuperHZ-2000" manufactured by Tosoh Corporation
Detector: RI (Differential Refractometer)
Data processing: "EcoSEC Data Analysis version 1.07" manufactured by Tosoh Corporation
Column temperature: 40 ° C
Developing solvent: Tetrahydrofuran Flow velocity: 0.35 mL / min Measurement sample: 7.5 mg of the sample was dissolved in 10 ml of tetrahydrofuran, and the obtained solution was filtered with a microfilter and used as the measurement sample.
Sample injection amount: 20 μl
Standard sample: According to the measurement manual of the above-mentioned "HLC-8320GPC", the following monodisperse polystyrene having a known molecular weight was used.

(Polystyrene monodisperse)
"A-300" manufactured by Tosoh Corporation
"A-500" manufactured by Tosoh Corporation
"A-1000" manufactured by Tosoh Corporation
"A-2500" manufactured by Tosoh Corporation
"A-5000" manufactured by Tosoh Corporation
"F-1" manufactured by Tosoh Corporation
"F-2" manufactured by Tosoh Corporation
"F-4" manufactured by Tosoh Corporation
"F-10" manufactured by Tosoh Corporation
"F-20" manufactured by Tosoh Corporation
"F-40" manufactured by Tosoh Corporation
"F-80" manufactured by Tosoh Corporation
"F-128" manufactured by Tosoh Corporation
"F-288" manufactured by Tosoh Corporation

The acid value is measured according to the method according to JIS K0070-1992, and the hydroxyl value is measured according to the method according to JIS K0070-1992.

Further, the metalworking oil base oil of the present invention is characterized in that its flash point is a relatively high temperature, but it can be set to 250 ° C. or higher in particular. In order to increase the ignition point, for example, in the above general formula (1), R ¹ and R ² may be a saturated hydrocarbon group containing a linear or branched structure having 7 to 17 carbon atoms, or R. ^{There is a method of using 4} as a linear saturated hydrocarbon group having 12 to 24 carbon atoms. Further, when a material having such a high flash point is prepared as a metalworking oil, it is possible to efficiently increase the flash point as the metalworking oil by containing it in an amount of 50% by mass or more.

Further, the metalworking oil base oil of the present invention is also characterized by having a low pour point (low temperature fluidity). Generally, the pour point of a metal processing oil base oil or a metal processing oil can be evaluated by a method based on JIS K2269, but the pour point of the metal processing oil base oil of the present invention is -10 ° C or less. It can be preferably obtained. In order to further lower the pour point, there is a method of using R ¹ and R ² in the general formula (1) as a hydrocarbon group containing one or a plurality of branched structures. Further, when such a product having a low pour point is prepared as a metalworking oil, the pour point as the metalworking oil can be suitably lowered by containing it in an amount of 50% by mass or more.

The method for producing a metal processing oil base oil of the present invention is a method for efficiently producing the above-mentioned metal processing oil base oil of the present invention, that is, a diester compound represented by the general formula (1), and has 3 carbon atoms. After reacting the olefin oxide (a1) of ~ 26 with the fatty acid (a2) having 4 to 30 carbon atoms, the number of carbon atoms is 4 to 30 with respect to the primary or secondary hydroxyl group generated by the ring opening of the epoxy group. It is characterized in that the fatty acid (a3) of the above is subjected to an esterification reaction.

Examples of the olefin oxide (a1) having 3 to 26 carbon atoms as the raw material used in the production method of the present invention include α-olefin oxide having 14 carbon atoms, and even commercially available ones can be synthesized. It may be the one that has been used.

Among these, α-olefin oxides are preferable, and α-olefins having 12 to 26 carbon atoms are preferable from the viewpoint of industrial availability and the fact that the ring-opening reaction of the epoxy group can easily proceed at a lower temperature. It is more preferably an oxide.

In the production method of the present invention, the epoxy group in the olefin oxide described above is reacted with a fatty acid (a2) having 4 to 30 carbon atoms to open a ring to generate a primary or secondary hydroxyl group in the structure. Is the first stage reaction.

Examples of the fatty acid (a2) having 4 to 30 carbon atoms include butyric acid, valeric acid, caproic acid, enanthic acid, capric acid, 2-ethylhexanoic acid, pelargonic acid, iso-nonanoic acid, capric acid and lauric acid. , Myristic acid, pentadecic acid, palmitic acid, 9-hexadecenoic acid, margaric acid, stearic acid, oleic acid, baxenoic acid, linoleic acid, eleostearic acid, arachidic acid, 8,11-eicosazienoic acid, meadic acid, arachidonic acid , Bechenic acid, lignoseric acid, nervonic acid, cellotic acid, montanic acid, melicic acid, etc., especially 2-ethylhexanoic acid and pelargon from the viewpoint of easily obtaining a compound capable of achieving both high ignition point and low temperature fluidity. It is preferable to use an acid or the like.

This reaction is a reaction between an epoxy group and a carboxy group, and may be carried out according to a conventionally known reaction of an epoxy group, and is not particularly limited in the present invention. As reaction conditions, for example, the carboxy group of the fatty acid (a2) having 4 to 30 carbon atoms is 1 to 3 mol with respect to 1 mol of the epoxy group of the olefin oxide (a1) having 3 to 26 carbon atoms. In a solvent-free or organic solvent, a catalyst such as quaternary onium salts, imidazoles, and TPP (triphenylphosphine) is used, and the reaction is easily carried out by stirring at 120 to 180 ° C, preferably 130 to 150 ° C. You can get things. The amount of the catalyst used may be appropriately set, but it is usually preferable to use the catalyst in the range of 0.001 to 0.3 parts by mass with respect to 100 parts by mass of the total amount of the raw material.

The organic solvent that can be used here is not particularly limited, and for example, ketones such as acetone, methyl ethyl ketone and cyclohexanone, methanol, ethanol, 1-propyl alcohol, isopropyl alcohol, 1-butanol and secondary butanol, Alcohol compounds such as tertiary butanol, glycol ethers such as methyl cellosolve, ethyl cellosolve, propylene glycol monomethyl ether acetate, ether compounds such as tetrahydrofuran, 1,4-dioxane, 1,3-dioxane, diethoxyethane, acetonitrile, dimethyl Examples thereof include aprotonic polar solvents such as sulfoxide and dimethylformamide. Each of these organic solvents may be used alone, or two or more kinds may be used in combination as appropriate for adjusting the polarity.

Tracking of the reaction (opening of the epoxy group) can be performed by measuring the epoxy equivalent of the solids in the reaction solution and can be terminated at the desired step, for example by lowering the temperature, but with the inclusion of by-products. From the viewpoint of further reducing the amount, it is preferable to confirm that the epoxy group content (calculated from the epoxy equivalent) is 0.5% by mass or less before terminating.

Due to the ring-opening reaction of the epoxy group, the linear product contains a primary or secondary hydroxyl group. In the next reaction, a fatty acid (a3) having 4 to 30 carbon atoms is esterified with these hydroxyl groups. The esterification reaction may be carried out under conventionally known esterification reaction conditions, and is not particularly limited.

Examples of the fatty acid (a3) having 4 to 30 carbon atoms include butyric acid, valeric acid, caproic acid, enanthic acid, capric acid, 2-ethylhexanoic acid, pelargonic acid, iso-nonanoic acid, capric acid and lauric acid. , Myristic acid, pentadecic acid, palmitic acid, 9-hexadecenoic acid, margaric acid, stearic acid, oleic acid, baxenoic acid, linoleic acid, eleostearic acid, arachidic acid, 8,11-eicosadienoic acid, meadic acid, arachidonic acid , Bechenic acid, lignoseric acid, nervonic acid, cellotic acid, montanic acid, melicic acid and the like, and it is particularly preferable to use 2-ethylhexanoic acid, pelargonic acid and the like from the viewpoint of ignition point and flow point.

The esterification reaction is, for example, a reaction using an esterification catalyst in a temperature range of 180 to 250 ° C. for 10 to 25 hours. For the fatty acid (a3) having 4 to 30 carbon atoms, the acid itself may be used as a raw material, or an esterified product thereof, an acid chloride product, an anhydride of a dicarboxylic acid, or the like may be used as a raw material. Further, since the reaction is an esterification reaction of a hydroxyl group and a carboxy group, the fatty acid (a3) is given to 1 mol of a primary or secondary hydroxyl group (calculated value from the measured value of the hydroxyl value) in the reaction system. It is preferable to use the carboxy group in the range of 1 to 1.5 mol.

Examples of the esterification catalyst include titanium-based catalysts such as tetraisopropyl titanate and tetrabutyl titanate; tin-based catalysts such as dibutyltin oxide; and organic sulfonic acid-based catalysts such as p-toluenesulfonic acid.

The amount of the esterification catalyst used may be appropriately set, but it is usually preferable to use the esterification catalyst in the range of 0.001 to 0.1 parts by mass with respect to 100 parts by mass of the total amount of the raw material.

The esterification reaction may be carried out without a solvent or in an organic solvent, but it is preferably carried out without a solvent because water and the like generated by the esterification can be efficiently removed. Therefore, it is preferable from the viewpoint of efficiency that the above-mentioned ring-opening reaction of the epoxy group is also performed without a solvent.

The fatty acid (a2) used in the ring-opening reaction of the epoxy group and the fatty acid (a3) used in the esterification reaction may be the same compound or different ones, but they are the same from the viewpoint of reaction efficiency. It is preferable to use one. At this time, when the olefin oxide (a1) is put into the reaction vessel, the fatty acid (a2) and the fatty acid (a3) can be collectively charged into the reaction vessel. In this method, a catalyst is added at any time. As a result, the reaction can be carried out continuously, which is a more efficient manufacturing method.

By removing the unreacted fatty acids (a2) and (a3) from the reaction product thus obtained, a diester compound that can be used as the base oil for metalworking oil of the present invention can be obtained. The catalyst used in the reaction may be removed or may remain in the system as it is.

According to the above-mentioned production method of the present invention, a product composed of almost a single compound can be obtained, and the content of by-products is extremely low. Further, since the esterification reaction is left in a relatively high temperature environment for a short time, it has a feature that the degree of coloring in the obtained product is lower than that in the case where the diester compound is obtained from an alcohol and a fatty acid. The low content of by-products also means that there are few components that adversely affect the flash point, which leads to efficiently exhibiting the performance of high flash point, which is the object of the present invention.

The diester compound obtained above may be used as it is as a metalworking oil, or may be used as a metalworking oil base oil and mixed with various other additives to obtain a metalworking oil.

When preparing as a metalworking oil, it is preferable to contain the metalworking oil base oil of the present invention in an amount of 50% by mass or more in the metalworking oil from the viewpoint of more efficiently exhibiting the effects of the present invention.

Additives that can be used when preparing as metalworking oil include, for example, antioxidants, lubricity improvers, metal detergents, ashless dispersants, rust inhibitors, metal deactivators, viscosity index improvers, and the like. Examples thereof include a fluid transfer curing agent and an antifoaming agent, and one type or two or more types may be used in combination.

Antioxidants include 2,6-di-tert-butyl-p-cresol, 2-tert-butyl-4-hydroxyanisole, 2,5-di-tert-butylhydroquinone, 4-hydroxymethyl-2,6. Phenols such as -di-tert-butylphenol, 4,4'-methylenebis-2,6-di-tert-butylphenol, 2,2'-methylenebis-4-methyl-6-tert-butylphenol, N-phenyl-α Examples thereof include amine-based compounds such as −naphthylamine, p, p'-dioctyldiphenylamine, p, p'-dinonyldiphenylamine, mixed dialkyldiphenylamine, and sulfur-based compounds such as phenothiazine, and phenol-based antioxidants are particularly preferable. These antioxidants may be used alone or in combination. When an antioxidant is used, it is usually added in an amount of 0.01 to 5% by mass, preferably 0.05 to 3% by mass, based on the base oil.

Examples of the lubricity improving agent include an oil-based agent, an abrasion resistant agent, and an extreme pressure agent. Examples of the oily agent include aliphatic saturated and unsaturated monoalcohols such as lauryl alcohol and oleyl alcohol, aliphatic saturated and unsaturated monoamines such as stearylamine and oleylamine, and aliphatic saturated and unsaturated monoamines such as lauric acid amide and oleic acid amide. Glycerin ethers such as carboxylic acid amides, bacillic alcohols, chimil alcohols and seraquil alcohols, alkyl or alkenyl polyglyceryl ethers such as lauryl polyglycerin ethers and oleyl polyglyceryl ethers, di (2-ethylhexyl) monoethanolamines, diisotridecyl monoethanol Examples thereof include poly (alkylene oxide) adducts of alkyl or alkenylamines such as amines. These oily agents can be used alone or in combination, and when an aliphatic monocarboxylic acid is used, it is usually 0.01 to 5% by mass, preferably 0.1 to 3% by mass, based on the base oil. Added.

As anti-wear / extreme pressure agents, tricresyl phosphate, cresyl diphenyl phosphate, alkyl phenyl phosphates, tributyl phosphate, phosphoric acid esters such as dibutyl phosphate, tributyl phosphite, dibutyl phosphite, triisopropyl phosphite, etc. Phosphoric acid esters and phosphorus-based such as amine salts thereof, sulfurized fatty acids such as sulfide oil and fat, oleic acid sulfide, sulfur-based such as dibenzyldisulfide, olefin sulfide, dialkyldisulfide, Zn-dialkyldithiophosphate, Zn- Examples thereof include organic metal compounds such as dialkyl dithiophosphate, Mo-dialkyldithiophosphate, and Mo-dialkyldithiocarbamate. These anti-wear agents may be used alone or in combination, and when the anti-wear agent is used, it is usually added in an amount of 0.01 to 10% by mass, preferably 0.1 to 5% by mass, based on the base oil. do.

Examples of metal detergents include Ca-petroleum sulphonate, perbasic Ca-petroleum sulphonate, Ca-alkylbenzene sulphonate, perbasic Ca-alkylbenzene sulphonate, Ba-alkylbenzene sulphonate, and hyperbasic Ba-alkylbenzene sulphonate. Phonate, Mg-alkylbenzene sulphonate, hyperbasic Mg-alkylbenzene sulphonate, Na-alkylbenzene sulphonate, hyperbasic Na-alkylbenzene sulphonate, Ca-alkylnaphthalen sulphonate, hyperbasic Ca- Metal sulphonates such as alkylnaphthalen sulphonates, metal sulphonates such as Ca-phenates, hyperbasic Ca-phenates, Ba-phenates, and perbasic Ba-fenates, metal salicylates such as Ca-salicylate, hyperbasic Ca-salicylate. , Ca-phosphonate, hyperbasic Ca-phosphonate, Ba-phosphonate, metal phosphonate such as hyperbasic Ba-phosphonate, hyperbasic Ca-carboxylate and the like are exemplified. These metal cleaning agents may be used alone or in combination, and when these metal cleaning agents are used, they are usually added in an amount of 1 to 10% by mass, preferably 2 to 7% by mass, based on the base oil.

Examples of the ashless dispersant include polyalkenylsuccinimide, polyalkenylsuccinamide, polyalkenylbenzylamine, polyalkenylsuccinate and the like. These ashless dispersants may be used alone or in combination, and when these ashless dispersants are used, they are usually added in an amount of 1 to 10% by mass, preferably 2 to 7% by mass, based on the base oil. ..

Anti-rust agents include alkyl or alkenyl succinic acid derivatives such as dodecenyl succinic acid half ester, octadecenyl succinic anhydride, dodecenyl succinic acid amide, sorbitan monooleate, glycerin monooleate, pentaerythritol monooleate and the like. Alcohol partial ester, Ca-petroleum sulphonate, Ca-alkylbenzene sulphonate, Ba-alkylbenzene sulphonate, Mg-alkylbenzene sulphonate, Na-alkylbenzene sulphonate, Zn-alkylbenzene sulphonate, Ca-alkylnaphthalenzul Examples thereof include metal sulfonates such as phonates, rosinamines, amines such as N-oleylzalkosine, and dialkylphosphiteamine salts. These rust inhibitors may be used alone or in combination, and when these rust inhibitors are used, they are usually 0.01 to 5% by mass, preferably 0.05 to 2% by mass with respect to the base oil. %Added.

Examples of the metal deactivating agent include benzotriazole-based compounds, thiadiazole-based compounds, and gallic acid ester-based compounds. Among these metal deactivators, gallic acid esters are preferable because they are excellent in hue and long-term durability. Specific examples of the gallic acid ester include gallic acid alkyl esters having an alkyl group having 3 to 12 carbon atoms. These metal deactivating agents may be used alone or in combination, and when these metal deactivating agents are used, they are usually 0.01 to 0.4% by mass, preferably 0.% by mass, based on the base oil. Add 01 to 0.2% by mass.

Examples of the viscosity index improver include olefin copolymers such as polyalkyl methacrylate, polyalkyl styrene, polybutene, ethylene-propylene copolymer, styrene-diene copolymer, and styrene-maleic anhydride copolymer. .. These viscosity index improvers may be used alone or in combination, and when these viscosity index improvers are used, they are usually 0.1 to 15% by mass, preferably 0.5 to 15% by mass based on the base oil. Add 7% by mass.

Examples of the pour point lowering agent include a condensate of chlorinated paraffin and alkylnaphthalene, a condensate of chlorinated paraffin and phenol, and the above-mentioned viscosity index improvers such as polyalkylmethacrylate, polyalkylstyrene, and polybutene. These pour point depressants may be used alone or in combination, and when these pour point depressants are used, they are usually 0.01 to 5% by mass, preferably 0.1 to 1% by weight based on the base oil. Add 3% by mass.

As the defoaming agent, liquid silicone is suitable, and when the defoaming agent is used, the addition amount thereof is usually 0.0005 to 0.01% by mass with respect to the base oil.

Examples of the metal processing used as the metal processing oil of the present invention include cutting processing, grinding processing, rolling processing, forging processing, pressing processing, drawing processing, rolling processing and the like. Further, since the metal processing oil based on the base oil of the present invention has excellent processing performance, it can be suitably used for heavy processing, difficult processing or difficult processing material processing.

When the metal processing oil of the present invention is used as a lubricating oil, in addition to the above-mentioned additives and the like, for example, mineral oil (hydrocarbon oil obtained by refining petroleum), synthetic hydrocarbon oil, animal and vegetable oil, present ester Other base oils such as organic acid esters, polyalkylene glycols, polyvinyl ethers, polyphenyl ethers, alkylphenyl ethers and silicone oils may be used in combination.

Examples of the mineral oil include solvent refined mineral oil, hydrorefined mineral oil, and wax isomerized oil. Examples of the synthetic hydrocarbon oil include poly-α-olefins, polybutenes, alkylbenzenes, alkylnaphthalene, cycloalkane derivatives, and isomerized oils of synthetic hydrocarbons obtained by the Fischer-Tropsch method.

Examples of the poly-α-olefin include α-olefins having 2 to 16 carbon atoms (for example, ethylene, propylene, 1-butene, 1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene and the like. ), Which has a kinematic viscosity at 100 ° C. of 1.0 to 25 mm ² / s or more, is exemplified. Examples of polybutene include those obtained by polymerizing isobutylene and those obtained by copolymerizing isobutylene with normal butylene, and examples of alkylbenzenes have a molecular weight of 200 to 450 substituted with a linear or branched alkyl group having 1 to 40 carbon atoms. Examples thereof include monoalkylbenzene, dialkylbenzene, trialkylbenzene, tetraalkylbenzene and the like. Examples of the alkylnaphthalene include monoalkylnaphthalene substituted with a linear or branched alkyl group having 1 to 30 carbon atoms, dialkylnaphthalene and the like. Examples of the cycloalkane derivative include synthetic naphthenic base oils containing a cyclohexane ring, a cycloheptane ring, a bicycloheptane ring, and a bicyclooctane ring. Examples of animal and vegetable oils include beef fat, pork fat, palm oil, palm oil, rapeseed oil, castor oil, sunflower oil and the like. Examples of organic acid esters other than this ester include fatty acid monoesters, aliphatic dibasic acid diesters, polyol esters and other esters. Examples of the polyalkylene glycol include a ring-opening polymer of an alcohol and a linear or branched alkylene oxide having 2 to 4 carbon atoms. Examples of the alkylene oxide include ethylene oxide, propylene oxide, and butylene oxide, and a polymer using one of these or a copolymer using a mixture of two or more can be used. Further, a compound in which the hydroxyl group portions at one end or both ends are etherified or esterified can also be used. The polyvinyl ether is a compound obtained by polymerizing a vinyl ether monomer, and the monomers are methyl vinyl ether, ethyl vinyl ether, isopropyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether, s-butyl vinyl ether, t-butyl vinyl ether, and n-pentyl vinyl ether. , N-Hexyl vinyl ether, 2-methoxyethyl vinyl ether, 2-ethoxyethyl vinyl ether and the like. Examples of the polyphenyl ether include compounds having a structure in which the meta positions of two or more aromatic rings are connected by an ether bond or a thioether bond, and specific examples thereof include bis (m-phenoxyphenyl) ether and m-bis (m-bis). Examples thereof include m-phenoxyphenoxy) benzene and thioethers in which one or more of these oxygens are replaced with sulfur. Examples of the alkyl phenyl ether include compounds in which polyphenyl ether is substituted with a linear or branched alkyl group having 6 to 18 carbon atoms, and an alkyl diphenyl ether substituted with one or more alkyl groups is particularly preferable. Examples of the silicone oil include modified silicones such as dimethyl silicone and methyl phenyl silicone, as well as long-chain alkyl silicones and fluorosilicones. Other components used in known lubricants can be appropriately blended as long as the effects of the present invention are not impaired.

Hereinafter, the present invention will be described in more detail based on examples. Parts and% in the example are based on mass unless otherwise specified.

Example 1
In the reaction vessel, 322.8 g (1.2 mol) of α-olefin oxide having 16 to 18 carbon atoms, 414.7 g (2.9 mol) of 2-ethylhexanoic acid, and 0.74 g of triphenylphosphine as an epoxy ring-opening catalyst. Was charged into a four-necked flask having an internal volume of 1 liter equipped with a thermometer, a stirrer, and a reflux cooler, and the temperature was raised to 140 ° C. while stirring under a nitrogen stream. The reaction was stopped when it fell below 5 wt%. Subsequently, 0.0369 g of tetraisopropyl titanate was added as an esterification catalyst, the temperature was gradually raised to 230 ° C., heating was continued at 230 ° C. until the hydroxyl value became 1 or less, and the purified water was continuously removed. .. After the reaction, unreacted 2-ethylhexanoic acid was distilled off under reduced pressure at 230 ° C. to obtain a metalworking oil base oil 1 (acid value 0.40, hydroxyl value 0.40, viscosity 43.1 mPa. s) was obtained in an amount of 530.4 g.

Example 2
In the reaction vessel, 243.1 g (1.1 mol) of α-olefin oxide having 14 carbon atoms, 417.1 g (2.6 mol) of n-nonanoic acid (manufactured by OXEA), and triphenylphosphine 0 as an epoxy ring-opening catalyst. .66 g was placed in a four-necked flask with an internal volume of 1 liter equipped with a thermometer, a stirrer, and a reflux condenser, and the temperature was raised to 140 ° C. while stirring under a nitrogen stream to reduce the amount of residual epoxy from the epoxy equivalent. The reaction was stopped when it fell below 0.5 wt%. Subsequently, 0.0330 g of tetraisopropyl titanate was added as an esterification catalyst, the temperature was gradually raised to 230 ° C., and heating was continued at 230 ° C. until the hydroxyl value became 1 or less, and the purified water was continuously removed. .. After the reaction, unreacted n-nonanoic acid was distilled off under reduced pressure at 230 ° C. to distill off the unreacted n-nonanoic acid under reduced pressure to obtain a metalworking oil base oil 2 (acid value 0.49, hydroxyl value 0.13, viscosity 26.9 mPa · s) which is a diester compound. ) Was obtained in an amount of 520.2 g.

Comparative Example 1
Oleic acid methyl ester was used as a comparative metalworking oil base oil.

The physical properties of the obtained base oil and comparative base oil were evaluated according to the following. The results are shown in Table 1.
[Evaluation of kinematic viscosity]
Measurement was performed using an Ubbelohde kinematic viscosity tube according to the method specified in JIS K-2283.
[Evaluation of lubricity]
The fusion load was measured using a shell-type four-ball tester according to the method specified in ASTM D-2783.
[Pour point evaluation]
The measurement was performed using a pour point tester according to the method specified in JIS K-2269.
[Flash point evaluation]
The measurement was performed using a Cleveland open type automatic flash point tester according to the method specified in JIS K-2265-4.

Claims (8)

The following general formula (1)

(In the formula, R ¹ and R ² are independently aliphatic hydrocarbon groups having 3 to 29 carbon atoms, R ³ is a hydrogen atom or a methyl group, and R ⁴ is a fat having 10 to 24 carbon atoms. It is a group saturated hydrocarbon group.)
Metal cutting and grinding oil base oil characterized by being represented by. In the general formula (1), R ¹ and R ² are independently aliphatic saturated hydrocarbon groups having ³ to 29 carbon atoms, R 3 is a hydrogen atom, and R ⁴ is 10 to 24 carbon atoms. The metal cutting and grinding oil base oil according to claim 1, which is an aliphatic saturated hydrocarbon group of the above. After reacting an olefin oxide (a1) having 12 to 26 carbon atoms with a fatty acid (a2) having 4 to 30 carbon atoms, a carbon atom is attached to a primary or secondary hydroxyl group generated by ring opening of an epoxy group. A method for producing a metal cutting and grinding oil base oil, which comprises subjecting a fatty acid (a3) of several 4 to 30 to an esterification reaction. The method for producing a metal cutting and grinding oil base oil according to claim 3, wherein the olefin oxide (a1) having 12 to 26 carbon atoms is an α-olefin oxide having 12 to 26 carbon atoms. The fatty acid (a2) having 4 to 30 carbon atoms and the fatty acid (a3) having 4 to 30 carbon atoms are saturated or unsaturated fatty acids containing one or more linear or branched structures having 8 to 12 carbon atoms. The method for producing a metal cutting and grinding oil base oil according to claim 3 or 4. The metal cutting grinding according to any one of claims 3 to 5, wherein the fatty acid (a2) having 4 to 30 carbon atoms and the fatty acid (a3) having 4 to 30 carbon atoms are collectively charged into a reaction vessel. Processing oil Base oil manufacturing method. Metal cutting grinding oil characterized by containing a metal cutting grinding base oil of claim 1 or 2, wherein. The metal cutting and grinding method using the metal cutting and grinding oil according to claim 7.