JP7621926B2 - Industrial Oil Composition - Google Patents

Description

The present invention relates to an industrial oil composition.

Patent Document 1 describes a lubricating oil composition that uses a mineral oil, synthetic oil, or oil as a base oil and does not contain a compound having a chlorine atom, and contains an organic molybdenum compound as component (A) and an active sulfur compound as component (B). It also describes the use of this lubricating oil composition as a metal processing oil.

JP 2004-211006 A

However, when the lubricating oil composition of Patent Document 1 is used for mechanical lubrication or metal processing, there is a problem in that odors, mist, and oily smoke are generated.

Therefore, the object of the present invention is to provide an industrial oil composition that suppresses odor, mist, and oily smoke.

The industrial oil composition of the present invention contains, as a base oil, at least one selected from a synthetic oil containing an α-olefin polymer and a mineral oil that has been hydrocracking-treated and has an unsaturated content of 10 mass% or less, and, as an antioxidant, a neutral phosphite derivative represented by the following formula (B), a 2,6-di-t-butylphenol derivative represented by the following formula (C), and a hindered amine compound represented by the following formula (D), and the base oil has a kinematic viscosity at 40°C of 40 cSt or less.

(In the above formula (B), R ^b21 to R ^b24 each independently represent an aliphatic hydrocarbon group having 10 to 16 carbon atoms, R ^b25 to R ^b28 each independently represent a linear or branched alkyl group having 1 to 6 carbon atoms, R ^b291 and R ^b292 each independently represent a hydrogen atom or a linear or branched alkyl group having 1 to 5 carbon atoms, and the total number of carbon atoms of R ^b291 and R ^b292 is 1 to 5.)

(In the above formula (C), R ^c1 is a linear or branched alkyl group having 1 to 12 carbon atoms.)

(In the above formula (D), R ^d21 and R ^d22 each independently represent an aliphatic hydrocarbon group having 1 to 10 carbon atoms, and R ^d23 represents a divalent aliphatic hydrocarbon group having 1 to 10 carbon atoms.)

The industrial oil composition of the present invention reduces odor, mist and oily smoke.

The following provides a detailed description of the form (embodiment) for carrying out the present invention. The present invention is not limited to the contents described in the following embodiment. The components described below include those that a person skilled in the art can easily imagine and those that are substantially the same. Furthermore, the configurations described below can be combined as appropriate. Various omissions, substitutions, or modifications of the configuration can be made without departing from the spirit of the present invention.

<Industrial oil composition of the embodiment>
The industrial oil composition of the embodiment contains, as a base oil, at least one selected from a synthetic oil containing an α-olefin polymer (poly α-olefin (PAO)) and a mineral oil having an unsaturated content of 10 mass% or less that has been subjected to hydrocracking, and contains, as an antioxidant, a neutral phosphite derivative represented by the following formula (B), a 2,6-di-t-butylphenol derivative represented by the following formula (C), and a hindered amine compound represented by the following formula (D). The base oil has a kinetic viscosity at 40°C of 40 cSt or less. In the industrial oil composition of the embodiment, a specific base oil and a specific antioxidant are combined, so that odor, mist, and oily smoke are suppressed. Specifically, when the industrial oil composition of the embodiment is used for metal processing in a metal processing machine, odor, mist, and oily smoke are suppressed even when the processing point becomes high temperature. In addition, when used for mechanical lubrication in the above-mentioned metalworking machine, the industrial oil composition for mechanical lubrication may seep out from the lubricating portion and mix with the industrial oil composition for metalworking as metalworking is performed.Even if the industrial oil composition for mechanical lubrication mixes with the industrial oil composition for metalworking in this way, the mixed industrial oil composition for mechanical lubrication does not generate odor, mist, or oily smoke.In addition, the industrial oil composition for mechanical lubrication can lubricate metalworking machines stably for a long period of time.

In contrast, conventional industrial oil compositions typically use common mineral oils and common antioxidants (diphenylamine derivatives, phenolic antioxidants, etc.). When the above industrial oil compositions are used, the low molecular weight components of the oils evaporate, generating odors, mist, and oily smoke, degrading the working environment. In addition, the antioxidants are quickly consumed, and therefore lose their antioxidant ability quickly. This promotes the breakdown of the mineral oil into smaller molecules through molecular destruction. This further promotes the generation of odors, mist, and oily smoke.

<Industrial oil composition of embodiment 1>
The industrial oil composition of embodiment 1 includes a base oil, an antioxidant, a mist suppressant, an oiliness agent, and a metal deactivator. The industrial oil composition of embodiment 1 is suitable for use in machine lubrication.

[Base oil]
The industrial oil composition of the first embodiment contains at least one selected from a synthetic oil containing an α-olefin polymer and a mineral oil having an unsaturated content of 10 mass% or less that has been subjected to hydrocracking. That is, the synthetic oil may be used alone or in combination of two or more as the base oil. The mineral oil may be used alone or in combination of two or more. Furthermore, one or more of the synthetic oils may be used in combination with one or more of the mineral oils. The base oil has a kinetic viscosity at 40°C of 40 cSt or less, preferably 7 cSt to 32 cSt, and more preferably 13 cSt to 26 cSt. In this specification, the kinetic viscosity at 40°C is a value measured in accordance with JIS K 2283-1993. In addition, when two or more kinds are combined to form a mixture of base oils, the kinetic viscosity at 40 ° C. in the mixture (whole base oil) is 40 cSt or less, preferably 7 cSt to 32 cSt, and more preferably 13 cSt to 26 cSt. Even if the kinetic viscosity at 40 ° C. of one of the synthetic oils or mineral oils used is outside the above range, the kinetic viscosity at 40 ° C. of the mixture (whole base oil) may be within the above range. In the industrial oil composition of embodiment 1, since the above base oil is used, the generation of odor, mist, and oily smoke is suppressed. Meanwhile, in the industrial oil composition of embodiment 1, it is preferable that the three types of antioxidants described later are dissolved in an amount that can fully exert the function of suppressing the generation of odor, mist, and oily smoke. When the above base oil is used, the three types of antioxidants can be dissolved in an amount that can fully exert the above suppression function.

The α-olefin polymer (poly α-olefin (PAO)) contained in the synthetic oil may be, for example, a homopolymer of one monomer selected from ethylene and an α-olefin having 3 to 18 carbon atoms, preferably an α-olefin having 10 to 18 carbon atoms, or a copolymer of at least two monomers selected from ethylene and an α-olefin having 3 to 18 carbon atoms, preferably an α-olefin having 10 to 18 carbon atoms. For example, a polymer (oligomer) of 1-decene and/or 1-dodecene may be used. The α-olefin polymer may be used alone or in combination of two or more. In addition, the synthetic oil containing the α-olefin polymer preferably has a kinetic viscosity at 40°C of 40 cSt or less, more preferably 7 cSt to 32 cSt, and even more preferably 13 cSt to 26 cSt.

The mineral oil is a mineral oil that has been hydrocracking-treated, or in other words, specifically, a mineral oil that belongs to Group 3 in the base oil category defined by the American Petroleum Institute (API). In this specification, the unsaturated content of the mineral oil is a value (content (mass%)) calculated using the saturated content measured in accordance with ASTM D 2007-93. In addition, the mineral oil preferably has a kinematic viscosity at 40°C of 40 cSt or less, more preferably 7 cSt to 32 cSt, and even more preferably 13 cSt to 26 cSt.

[Antioxidants]
In the industrial oil composition of the first embodiment, three types of antioxidants are used in combination: a neutral phosphite derivative represented by the following formula (B), a 2,6-di-t-butylphenol derivative represented by the following formula (C), and a hindered amine compound represented by the following formula (D). Therefore, even if the composition is used for a long period of time during machine lubrication, and even if high pressure is continuously applied to the sliding parts, the generation of odor, mist, and oily smoke is suppressed. In addition, the consumption of the antioxidant can be suppressed more than when any of the neutral phosphite derivative, the 2,6-di-t-butylphenol derivative, and the hindered amine compound is not contained. Therefore, the antioxidant ability of the industrial oil composition can be maintained for a long period of time. That is, the industrial oil composition of the first embodiment has excellent oxidation stability, is suppressed in viscosity change, and can be used for a long period of time. Furthermore, the function of suppressing the generation of odor, mist, and oily smoke can be maintained for a long period of time.

The neutral phosphite derivative is represented by the following formula (B). The neutral phosphite derivative may be used alone or in combination of two or more types. Since the neutral phosphite derivative is a dimer, it is difficult to evaporate and can efficiently exhibit antioxidant performance.

In formula (B), R ^b21 to R ^b24 each independently represent an aliphatic hydrocarbon group having 10 to 16 carbon atoms.

The aliphatic hydrocarbon group having 10 to 16 carbon atoms may be a linear, branched or cyclic aliphatic hydrocarbon group, and may be a saturated or unsaturated aliphatic hydrocarbon group. As the aliphatic hydrocarbon group having 10 to 16 carbon atoms, specifically, linear alkyl groups such as decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl and hexadecyl (cetyl) groups are preferably used.

R ^b25 to R ^b28 each independently represent a linear or branched alkyl group having 1 to 6 carbon atoms.

Examples of linear or branched alkyl groups having 1 to 6 carbon atoms include methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, isopropyl, sec-butyl, isobutyl, t-butyl, isopentyl, t-pentyl, neopentyl, and isohexyl.

The neutral phosphite has specific substituents in R ^b25 to R ^b28 , and therefore has excellent anti-wear properties in addition to antioxidant performance. This is thought to be because the presence of specific substituents in R ^b25 to R ^b28 makes the film of the industrial oil composition adhered to the sliding parts stronger.

In particular, when R ^b25 and R ^b27 are linear alkyl groups having 1 to 6 carbon atoms, preferably 1 to 3 carbon atoms, and R ^b26 and R ^b28 are branched alkyl groups having 3 to 6 carbon atoms, preferably 3 to 4 carbon atoms, the effect of improving the wear resistance is further enhanced.

R ^b291 and R ^b292 each independently represent a hydrogen atom or a linear or branched alkyl group having 1 to 5 carbon atoms.

Examples of linear or branched alkyl groups having 1 to 5 carbon atoms include methyl, ethyl, n-propyl, n-butyl, n-pentyl, isopropyl, sec-butyl, isobutyl, t-butyl, isopentyl, t-pentyl, and neopentyl.

However, the total number of carbon atoms in R ^b291 and R ^b292 is 1 to 5. Therefore, for example, when R ^b291 is a hydrogen atom, R ^b292 is a straight-chain or branched alkyl group having 1 to 5 carbon atoms, when R ^b291 is a methyl group, R ^b292 is a straight-chain or branched alkyl group having 1 to 4 carbon atoms, and when R ^b291 is an ethyl group, R ^b292 is a straight-chain or branched alkyl group having 2 to 3 carbon atoms.

In order to make the film of the industrial oil composition stronger, it is more preferable that R ^b291 is a hydrogen atom and R ^b292 is a straight-chain or branched alkyl group having 1 to 5 carbon atoms.

The 2,6-di-t-butylphenol derivative is represented by the following formula (C). The 2,6-di-t-butylphenol derivative may be used alone or in combination of two or more kinds.

In formula (C), R ^c1 is a linear or branched alkyl group having 1 to 12 carbon atoms. Examples of the linear or branched alkyl group having 1 to 12 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a t-butyl group, an isobutyl group, an n-pentyl group, an isopentyl group, a t-pentyl group, a neopentyl group, a hexyl group, a heptyl group, an isoheptyl group, an n-octyl group, an isooctyl group, a 2-ethylhexyl group, a nonyl group, and a decyl group. When R c1 is an alkyl group as described above, the compatibility of the 2,6-di-t-butylphenol derivative is improved.

The hindered amine compound is represented by the following formula (D). The hindered amine compound may be used alone or in combination of two or more types.

R ^d21 and R ^d22 each independently represent an aliphatic hydrocarbon group having 1 to 10 carbon atoms.

The aliphatic hydrocarbon group having 1 to 10 carbon atoms may be a linear, branched or cyclic aliphatic hydrocarbon group, and may be a saturated or unsaturated aliphatic hydrocarbon group.

Specific examples of the aliphatic hydrocarbon group having 1 to 10 carbon atoms that can be used preferably include linear or branched alkyl groups such as methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, heptyl, octyl, nonyl, decyl, isopropyl, sec-butyl, isobutyl, t-butyl, isopentyl, t-pentyl, neopentyl, isohexyl, and 2-ethylhexyl. Of these, linear or branched alkyl groups having 5 to 10 carbon atoms are more preferred from the viewpoint of improving durability.

R ^d23 represents a divalent aliphatic hydrocarbon group having 1 to 10 carbon atoms.

As divalent aliphatic hydrocarbon groups having 1 to 10 carbon atoms, divalent linear or branched alkylene groups such as methylene, 1,2-ethylene, 1,3-propylene, 1,4-butylene, 1,5-pentylene, 1,6-hexylene, 1,7-heptylene, 1,8-octylene, 1,9-nonylene, 1,10-decylene, and 3-methyl-1,5-pentylene are preferably used. Of these, divalent linear or branched alkylene groups having 5 to 10 carbon atoms are more preferred from the viewpoint of improving durability.

From the viewpoint of improving durability, it is more preferable that the sum of the numbers of carbon atoms of R ^d21 , R ^d22 and R ^d23 is 16 to 30.

In the industrial oil composition of embodiment 1, the above three types of antioxidants are preferably contained in a total amount of 0.5 parts by mass to 7.0 parts by mass, and more preferably 0.7 parts by mass to 3.1 parts by mass, per 100 parts by mass of base oil. When the antioxidants are contained in the above amounts, the generation of odor, mist, and oily smoke is further suppressed during machine lubrication, even if the machine is used for a long period of time and even if high pressure is continuously applied to the sliding parts. In addition, from the viewpoint of further suppressing the generation of odor, mist, and oily smoke, in the industrial oil composition of embodiment 1, the neutral phosphite derivative is more preferably contained in an amount of 0.01 parts by mass to 5.0 parts by mass, and particularly preferably 0.1 parts by mass to 0.5 parts by mass, per 100 parts by mass of base oil.

[Mist prevention agent]
The industrial oil composition of embodiment 1 contains a hydrocarbon-based polymer compound as a mist suppressant. The use of the hydrocarbon-based polymer compound makes it possible to suitably suppress the generation of mist when the industrial oil composition is used.

Examples of the hydrocarbon-based polymeric compounds include polyisobutylene and ethylene-propylene copolymers. The hydrocarbon-based polymeric compounds may be used alone or in combination of two or more. Of these, polyisobutylene is preferably used.

The number average molecular weight of the hydrocarbon polymer compound is preferably 100,000 to 3,000,000, more preferably 200,000 to 2,000,000, even more preferably 250,000 to 1,000,000, and particularly preferably 300,000 to 700,000. Here, the number average molecular weight means the number average molecular weight in terms of polystyrene measured by gel permeation chromatography.

In the industrial oil composition of embodiment 1, the hydrocarbon polymer compound is preferably contained in an amount of 0.01 parts by mass or more and 5 parts by mass or less per 100 parts by mass of the base oil, from the viewpoint of preventing mist.

[Oil-based agent and metal deactivator]
The industrial oil composition of embodiment 1 contains zinc dialkyldithiophosphate as an oiliness agent. When the industrial oil composition of embodiment 1 contains zinc dialkyldithiophosphate, the sliding property is improved and wear can be prevented. In addition, the industrial oil composition of embodiment 1 contains a benzotriazole derivative as a metal deactivator. When the industrial oil composition of embodiment 1 contains a benzotriazole derivative, the metal surface can be protected and corrosion can be prevented. In the industrial oil composition of embodiment 1, the specific oiliness agent and the metal deactivator are combined, so that the machine can be lubricated for a longer period of time.

The alkyl group of zinc dialkyldithiophosphate may be a primary type alkyl group or a secondary type alkyl group. A single molecule may have both a primary type alkyl group and a secondary type alkyl group. The alkyl group may be linear or branched. There is no particular restriction on the number of carbon atoms in the alkyl group, but from the viewpoint of preventing wear, it is preferably 3 to 12, and more preferably 3 to 8. One type of zinc dialkyldithiophosphate may be used alone, or two or more types may be used in combination.

The benzotriazole derivative is preferably represented by the following formula (E). When such a benzotriazole derivative is contained, corrosion can be further prevented.

In the above formula (E), R ^e1 represents a hydrogen atom or an alkyl group having 1 to 18 carbon atoms, and R ^e2 and R ^e3 each independently represent an alkyl group having 1 to 18 carbon atoms. The benzotriazole derivatives may be used alone or in combination of two or more kinds.

In the industrial oil composition of embodiment 1, the zinc dialkyldithiophosphate is preferably contained in an amount of 0.01 parts by mass or more and 5 parts by mass or less per 100 parts by mass of the base oil. Also, in the industrial oil composition of embodiment 1, the benzotriazole derivative is preferably contained in an amount of 0.01 parts by mass or more and 5 parts by mass or less per 100 parts by mass of the base oil.

The industrial oil composition of embodiment 1 can be prepared by appropriately mixing the above-mentioned components.

<Industrial oil composition of embodiment 2>
The industrial oil composition of the second embodiment includes a base oil, an antioxidant, a mist suppressant, an extreme pressure agent, and a metal deactivator. The industrial oil composition of the second embodiment is suitable for use in metal processing.

[Base oil]
The industrial oil composition of the second embodiment contains at least one selected from a synthetic oil containing an α-olefin polymer and a mineral oil having an unsaturated content of 10 mass% or less that has been subjected to hydrocracking. That is, the synthetic oil may be used alone or in combination of two or more as the base oil. The mineral oil may be used alone or in combination of two or more. Furthermore, one or more of the synthetic oils may be used in combination with one or more of the mineral oils. The base oil has a kinetic viscosity at 40° C. of 40 cSt or less, preferably 7 cSt or more and 32 cSt or less, and more preferably 13 cSt or more and 26 cSt or less. When two or more types are combined to form a mixture of base oils, the mixture (whole base oil) has a kinetic viscosity at 40° C. of 40 cSt or less, preferably 7 cSt or more and 32 cSt or less, and more preferably 13 cSt or more and 26 cSt or less. Even if the kinetic viscosity at 40°C of one of the synthetic oils or mineral oils used is outside the above range, it is sufficient that the kinetic viscosity at 40°C of the mixture (whole base oil) is within the above range. Since the industrial oil composition of embodiment 2 uses the above base oil, the generation of odor, mist, and oily smoke is suppressed. Meanwhile, in the industrial oil composition of embodiment 2, it is preferable that the three types of antioxidants described below are dissolved in an amount that can fully exert the function of suppressing the generation of odor, mist, and oily smoke. When the above base oil is used, the three types of antioxidants can be dissolved in an amount that can fully exert the above-mentioned suppression function.

Details of the α-olefin polymer (poly α-olefin (PAO)) contained in the synthetic oil are the same as those described in embodiment 1. Details of the mineral oil are also the same as those described in embodiment 1.

[Antioxidants]
In the industrial oil composition of embodiment 2, three types of antioxidants are used in combination: a neutral phosphite derivative represented by formula (B), a 2,6-di-t-butylphenol derivative represented by formula (C), and a hindered amine compound represented by formula (D). Therefore, even if the processing point becomes hot during metal processing, the generation of odor, mist, and oily smoke is suppressed. Furthermore, the generation of odor, mist, and oily smoke is suppressed more than when any of the neutral phosphite derivative, the 2,6-di-t-butylphenol derivative, and the hindered amine compound is not contained. The details of the antioxidant, including the preferred range and reasons, are the same as those explained in embodiment 1.

In the industrial oil composition of embodiment 2, the above three types of antioxidants are preferably contained in a total amount of 0.5 parts by mass to 7.0 parts by mass, and more preferably 0.7 parts by mass to 3.1 parts by mass, per 100 parts by mass of base oil. When the antioxidants are contained in the above amounts, the generation of odor, mist, and oil smoke is further suppressed even if the processing point becomes hot during metal processing. In addition, from the viewpoint of further suppressing the generation of odor, mist, and oil smoke, in the industrial oil composition of embodiment 2, it is more preferable that the neutral phosphite derivative is contained in an amount of 0.01 parts by mass to 5.0 parts by mass, and particularly preferably 0.1 parts by mass to 0.5 parts by mass, per 100 parts by mass of base oil.

[Mist prevention agent]
The industrial oil composition of embodiment 2 contains a hydrocarbon-based polymer compound as a mist inhibitor. The use of the hydrocarbon-based polymer compound can suitably suppress the generation of mist when the industrial oil composition is used. Details of the mist inhibitor, including the preferred range, amount, and reasons, are the same as those described in embodiment 1.

[Extreme Pressure Agents and Metal Deactivators]
The industrial oil composition of embodiment 2 contains a sulfur compound as an extreme pressure agent. Specifically, it contains an active sulfur compound. When the industrial oil composition of embodiment 2 contains an active sulfur compound, the processability can be improved even when the processing point is at a high temperature. In addition, the industrial oil composition of embodiment 2 contains a thiadiazole derivative as a metal deactivator. When the industrial oil composition of embodiment 2 contains a thiadiazole derivative, the metal surface can be protected and corrosion can be prevented even when the processing point is at a high temperature. In addition, copper-based metals can be processed. In the industrial oil composition of embodiment 2, the specific extreme pressure agent and metal deactivator are combined, so that metals can be processed more suitably.

The active sulfur compound may be any compound containing active sulfur in the molecule. Here, the active sulfur compound refers to, for example, a compound that contains sulfur atoms but does not contain metal atoms or phosphorus atoms, and that is diluted with refined mineral oil so that the sulfur content is 1% by mass, and has a copper plate corrosion of 2 to 4 as measured according to JIS K2513 (petroleum products - copper plate corrosion test method; test tube method, heated at 100 ° C for 1 hour). On the other hand, among compounds that contain sulfur atoms but do not contain metal atoms or phosphorus atoms, a compound that has a copper plate corrosion of 1 in the above test method is called an inactive sulfur compound. Examples of active sulfur compounds include polysulfides, sulfurized oils and fats, powdered sulfur, sulfurized mineral oil, sulfurized esters, sulfurized olefins, sulfurized fatty acids, and sulfurized lard. Of these, sulfurized olefins, sulfurized fatty acids, and sulfurized lard are preferably used. The active sulfur compounds may be used alone or in combination of two or more types. Even if the raw materials and sulfur content are similar to these active sulfur compounds, they may be inactive sulfur compounds depending on the manufacturing conditions, etc.

The thiadiazole derivative is preferably 2,5-bis(alkyldithio)-1,3,4-thiadiazole, and is represented by the following formula (F). When such a thiadiazole derivative is contained, corrosion can be further prevented even when the processing point becomes hot.

In the above formula (F), R ^f1 and R ^f2 each independently represent an alkyl group having 1 to 20 carbon atoms, and a and b each independently represent 1, 2, or 3. The thiadiazole derivative may be used alone or in combination of two or more kinds.

In the industrial oil composition of embodiment 2, the sulfur compound is preferably contained in an amount of 0.01 parts by mass or more and 20 parts by mass or less per 100 parts by mass of the base oil. Also, in the industrial oil composition of embodiment 2, the thiadiazole derivative is preferably contained in an amount of 0.01 parts by mass or more and 5 parts by mass or less per 100 parts by mass of the base oil.

The industrial oil composition of embodiment 2 can be prepared by appropriately mixing the above-mentioned components.

<Other embodiments of industrial oil compositions>
As the industrial oil composition of other embodiments, other additives may be further included in the industrial oil composition of embodiments 1 and 2. Examples of the other additives include chlorinated paraffin. It is preferable that the other additives are included in the industrial oil composition to the extent that they do not interfere with the effects of the function of suppressing the generation of odor, mist, and oily smoke.

In addition, the industrial oil composition of another embodiment may be a composition that does not contain at least one of the mist suppressant, oiliness agent, and metal deactivator, as compared to the industrial oil composition of embodiment 1.

Alternatively, the industrial oil composition of embodiment 2 may be a composition that does not contain at least one of a mist inhibitor, an extreme pressure agent, and a metal deactivator. When the industrial oil composition of embodiment 2 does not contain the above-mentioned metal deactivator, it can be suitably used for processing metals other than copper-based metals, such as metals containing iron. Furthermore, when the industrial oil composition of embodiment 2 does not contain the above-mentioned metal deactivator, an inactive sulfur compound may be used as the extreme pressure agent instead of the active sulfur compound.

All of these industrial oil compositions effectively suppress the generation of odors, mist, and oily smoke.

Based on the above, the present invention relates to the following.
[1] At least one base oil selected from the group consisting of synthetic oils containing α-olefin polymers and mineral oils that have been subjected to hydrocracking and have an unsaturated content of 10 mass% or less;
The industrial oil composition contains, as antioxidants, a neutral phosphite derivative represented by the following formula (B), a 2,6-di-t-butylphenol derivative represented by the following formula (C), and a hindered amine compound represented by the following formula (D), and the base oil has a kinetic viscosity at 40° C. of 40 cSt or less.

(In the above formula (B), R ^b21 to R ^b24 each independently represent an aliphatic hydrocarbon group having 10 to 16 carbon atoms, R ^b25 to R ^b28 each independently represent a linear or branched alkyl group having 1 to 6 carbon atoms, R ^b291 and R ^b292 each independently represent a hydrogen atom or a linear or branched alkyl group having 1 to 5 carbon atoms, and the total number of carbon atoms of R ^b291 and R ^b292 is 1 to 5.)

(In the above formula (C), R ^c1 is a linear or branched alkyl group having 1 to 12 carbon atoms.)

(In the above formula (D), R ^d21 and R ^d22 each independently represent an aliphatic hydrocarbon group having 1 to 10 carbon atoms, and R ^d23 represents a divalent aliphatic hydrocarbon group having 1 to 10 carbon atoms.)
[2] The industrial oil composition according to [1], comprising the antioxidant in a total amount of 0.5 parts by mass or more and 5.0 parts by mass or less per 100 parts by mass of the base oil.
The industrial oil composition suppresses odor, mist and oily smoke.
[3] The industrial oil composition according to [1] or [2], further comprising a hydrocarbon-based polymer compound as a mist suppressant.
The above industrial oil composition further suppresses odor, mist and oily smoke.
[4] The industrial oil composition according to any one of [1] to [3], further comprising zinc dialkyldithiophosphate as an oiliness agent, and used for machine lubrication.
[5] The industrial oil composition according to [4], further comprising a benzotriazole derivative as a metal deactivator.
The above industrial oil composition is suitable for use in machine lubrication.
[6] The industrial oil composition according to any one of [1] to [3], further comprising a sulfur compound as an extreme pressure agent, for use in metal processing.
[7] The industrial oil composition according to [6], wherein the sulfur compound is an active sulfur compound and further contains a thiadiazole derivative as a metal deactivator.
The above industrial oil composition is suitable for use in metal working.

[Example]
The present invention will be described in more detail below based on examples, but the present invention is not limited to these examples.
[Example 1-1]
A synthetic oil was used as the base oil, specifically, poly-α-olefin (manufactured by Chevron Phillips Chemical Company, PAO 4 cSt (grade), kinematic viscosity at 40° C. 16.8 cSt) was used as the synthetic oil.
For 100 parts by mass of this base oil, 0.1 parts by mass of 4,4'-butylidenebis(3-methyl-6-t-butylphenyl ditridecyl phosphite) as a neutral phosphite derivative and 0.2 parts by mass of octyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propanoate (CAS No. An industrial oil composition was obtained by mixing 0.5 parts by mass of bis(2,2,6,6-tetramethyl-1-(octyloxy)piperidin-4-yl) decanedioate (trade name: PARATAC, manufactured by Triiso) as a hindered amine compound, 0.1 parts by mass of polyisobutylene (trade name: PARATAC, manufactured by Triiso) as a mist suppressant, 1 part by mass of zinc dialkyldithiophosphate (trade name: Adithin (registered trademark) RC308, manufactured by Lanxess KK) as an oiliness agent, and 0.5 parts by mass of 1-(N,N-bis(2-ethylhexyl)aminomethyl)benzotriazole (trade name: Irgamet (registered trademark) 39, manufactured by BASF Japan Ltd.) as a metal deactivator.

[Example 1-2]
An industrial oil composition was obtained in the same manner as in Example 1-1, except that the components were mixed in the amounts shown below: That is, 0.5 parts by mass of a neutral phosphite derivative, 0.5 parts by mass of a 2,6-di-t-butylphenol derivative, 0.1 parts by mass of a hindered amine compound, 0.1 parts by mass of a mist suppressant, 1 part by mass of an oiliness agent, and 0.5 parts by mass of a metal deactivator were mixed with 100 parts by mass of a base oil to obtain an industrial oil composition.

[Examples 1-3-1 to 1-3-6]
An industrial oil composition was obtained in the same manner as in Example ^1-1 , except that a compound in which the substituents in the above formula (B) were changed to the substituents in Table 1 was used instead of 4,4'-butylidenebis(3-methyl- ⁶ -t-butylphenyl ditridecyl phosphite) (R ^b21 to R ^b24 = tridecyl groups, R ^b25 , R ^b27 = methyl groups, R b26, R b28 = t-butyl groups, R ^b291 = hydrogen atom, R ^b292 = n-propyl group) as the neutral phosphite derivative.

[Examples 1-4-1 to 1-4-6]
An industrial oil composition was obtained in the same manner as in Example ^1-1 , except that a compound in which the substituents in the above formula (D) were changed to the substituents in Table 2 was used instead of bis(2,2,6,6-tetramethyl-1-(octyloxy)piperidin-4-yl) decanedioate (R ^d21 , R d22 = n-octyl group, R ^d23 = 1,8-octylene group) as the hindered amine compound.

[Example 1-5-1]
An industrial oil composition was obtained in the same manner as in Example 1-1, except that polyisobutylene (trade name: Struktol AM, manufactured by Sill+Seilach) was used as the mist suppressant.

[Example 1-5-2]
An industrial oil composition was obtained in the same manner as in Example 1-1, except that polyisobutylene (trade name: Struktol C, manufactured by Sill+Seilach) was used as the mist suppressant.

[Example 1-5-3]
An industrial oil composition was obtained in the same manner as in Example 1-1, except that polyisobutylene (trade name: Struktol S, manufactured by Sill+Seilach) was used as the mist suppressant.

[Example 1-6-1]
An industrial oil composition was obtained in the same manner as in Example 1-1, except that the following synthetic oil was used as the base oil. That is, a mixture of poly-α-olefin (DURACYN 162, manufactured by INEOS Oligomers, kinematic viscosity at 40°C: 5.5 cSt) and poly-α-olefin (DURACYN 164, manufactured by INEOS Oligomers, kinematic viscosity at 40°C: 17.0 cSt) was used as the synthetic oil. The above mixture (whole base oil) had a kinematic viscosity at 40°C of 10 cSt.

[Example 1-6-2]
An industrial oil composition was obtained in the same manner as in Example 1-1, except that the following synthetic oil was used as the base oil: That is, poly-α-olefin (Spectrasyn 4, manufactured by Exxon Mobil Corporation, kinematic viscosity at 40° C.: 20 cSt) was used as the synthetic oil.

[Example 1-6-3]
An industrial oil composition was obtained in the same manner as in Example 1-1, except that the following synthetic oil was used as the base oil: That is, poly-α-olefin (Spectrasyn 5, manufactured by Exxon Mobil Corporation, kinematic viscosity at 40° C.: 25 cSt) was used as the synthetic oil.

[Example 1-6-4]
An industrial oil composition was obtained in the same manner as in Example 1-1, except that the following synthetic oil was used as the base oil: That is, poly-α-olefin (Ineos Oligomers, Durasin 166, kinematic viscosity at 40° C.: 31 cSt) was used as the synthetic oil.

[Example 2-1]
A mineral oil was used as the base oil. Specifically, a mineral oil belonging to Group 3 (Ultra-S3, manufactured by S-OIL Corporation, kinematic viscosity at 40° C. 14 cSt, unsaturated content 10 mass % or less) was used.
For 100 parts by mass of this base oil, 0.1 parts by mass of 4,4'-butylidenebis(3-methyl-6-t-butylphenyl ditridecyl phosphite) as a neutral phosphite derivative and 0.2 parts by mass of octyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propanoate (CAS No. An industrial oil composition was obtained by mixing 0.5 parts by mass of bis(2,2,6,6-tetramethyl-1-(octyloxy)piperidin-4-yl) decanedioate (trade name: PARATAC, manufactured by Triiso) as a hindered amine compound, 0.1 parts by mass of polyisobutylene (trade name: PARATAC, manufactured by Triiso) as a mist suppressant, 1 part by mass of zinc dialkyldithiophosphate (trade name: Adithin (registered trademark) RC308, manufactured by Lanxess KK) as an oiliness agent, and 0.5 parts by mass of 1-(N,N-bis(2-ethylhexyl)aminomethyl)benzotriazole (trade name: Irgamet (registered trademark) 39, manufactured by BASF Japan Ltd.) as a metal deactivator.

[Example 2-2]
An industrial oil composition was obtained in the same manner as in Example 2-1, except that the components were mixed in the amounts shown below: That is, 0.5 parts by mass of a neutral phosphite derivative, 0.5 parts by mass of a 2,6-di-t-butylphenol derivative, 0.1 parts by mass of a hindered amine compound, 0.1 parts by mass of a mist suppressant, 1 part by mass of an oiliness agent, and 0.5 parts by mass of a metal deactivator were mixed with 100 parts by mass of a base oil to obtain an industrial oil composition.

[Examples 2-3-1 to 2-3-6]
An industrial oil composition was obtained in the same manner as in Example ^2-1 , except that a compound in which the substituents in the above formula (B) were changed to the substituents in Table 3 was used instead of 4,4'-butylidenebis(3-methyl- ⁶ -t-butylphenyl ditridecyl phosphite) (R ^b21 to R ^b24 = tridecyl groups, R ^b25 , R ^b27 = methyl groups, R b26 , R b28 = t-butyl groups, R ^b291 = hydrogen atom, R ^b292 = n-propyl group) as the neutral phosphite derivative.

[Examples 2-4-1 to 2-4-6]
An industrial oil composition was obtained in the same manner as in Example ^2-1 , except that a compound in which the substituents in the above formula (D) were changed to the substituents in Table 4 was used instead of bis(2,2,6,6-tetramethyl-1-(octyloxy)piperidin-4-yl) decanedioate (R ^d21 , R d22 = n-octyl group, R ^d23 = 1,8-octylene group) as the hindered amine compound.

[Example 2-5-1]
An industrial oil composition was obtained in the same manner as in Example 2-1, except that polyisobutylene (trade name: Struktol AM, manufactured by Sill+Seilach) was used as the mist suppressant.

[Example 2-5-2]
An industrial oil composition was obtained in the same manner as in Example 2-1, except that polyisobutylene (trade name: Struktol C, manufactured by Sill+Seilach) was used as the mist suppressant.

[Example 2-5-3]
An industrial oil composition was obtained in the same manner as in Example 2-1, except that polyisobutylene (trade name: Struktol S, manufactured by Sill+Seilach) was used as the mist suppressant.

[Example 2-6-1]
An industrial oil composition was obtained in the same manner as in Example 2-1, except that the following mineral oil was used as the base oil. That is, a mixture of a mineral oil belonging to Group 3 (Ultra-S2, manufactured by S-OIL Corporation, kinematic viscosity at 40°C of 7.62 cSt, unsaturated content of 10 mass% or less) and a mineral oil belonging to Group 3 (Ultra-S3, manufactured by S-OIL Corporation, kinematic viscosity at 40°C of 14 cSt, unsaturated content of 10 mass% or less) was used as the mineral oil. The mixture (whole base oil) had a kinematic viscosity at 40°C of 10 cSt and an unsaturated content of 10 mass% or less.

[Example 2-6-2]
An industrial oil composition was obtained in the same manner as in Example 2-1, except that the following mineral oil was used as the base oil: Group 3 mineral oil (Ultra-S4, manufactured by S-OIL Corporation, kinematic viscosity at 40°C of 19.7 cSt, unsaturated content of 10 mass% or less) was used as the mineral oil.

[Example 2-6-3]
An industrial oil composition was obtained in the same manner as in Example 2-1, except that the following mineral oil was used as the base oil. That is, a mixture of a mineral oil belonging to Group 3 (Ultra-S4 manufactured by S-OIL Corporation, kinematic viscosity at 40°C of 19.7 cSt, unsaturated content of 10 mass% or less) and a mineral oil belonging to Group 3 (Ultra-S6 manufactured by S-OIL Corporation, kinematic viscosity at 40°C of 32.5 cSt, unsaturated content of 10 mass% or less) was used as the mineral oil. The mixture (whole base oil) had a kinematic viscosity at 40°C of 26 cSt and an unsaturated content of 10 mass% or less.

[Example 2-6-4]
An industrial oil composition was obtained in the same manner as in Example 2-1, except that the following mineral oil was used as the base oil: Group 3 mineral oil (Ultra-S2, manufactured by S-OIL Corporation, kinematic viscosity at 40°C of 7.62 cSt, unsaturated content of 10 mass% or less).

[Example 3-1]
A synthetic oil was used as the base oil, specifically, poly-α-olefin (manufactured by Chevron Phillips Chemical Company, PAO 4 cSt (grade), kinematic viscosity at 40° C. 16.8 cSt) was used as the synthetic oil.
For 100 parts by mass of this base oil, 0.1 parts by mass of 4,4'-butylidenebis(3-methyl-6-t-butylphenyl ditridecyl phosphite) as a neutral phosphite derivative and 0.2 parts by mass of octyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propanoate (CAS No. An industrial oil composition was obtained by mixing 0.5 parts by mass of bis(2,2,6,6-tetramethyl-1-(octyloxy)piperidin-4-yl) decanedioate (trade name: PARATAC, manufactured by Triiso) as a hindered amine compound, 0.1 parts by mass of polyisobutylene (trade name: PARATAC, manufactured by Triiso) as a mist suppressant, 1 part by mass of sulfurized olefin (trade name: GS-440L, manufactured by DIC Corporation) as an extreme pressure agent, which is an active sulfur compound, and 0.5 parts by mass of 2,5-bis(alkyldithio)-1,3,4-thiadiazole (trade name: R100, manufactured by DIC Corporation) as a metal deactivator.

[Example 3-2]
An industrial oil composition was obtained in the same manner as in Example 3-1, except that the components were mixed in the amounts shown below: That is, 0.5 parts by mass of a neutral phosphite derivative, 0.5 parts by mass of a 2,6-di-t-butylphenol derivative, 0.1 parts by mass of a hindered amine compound, 0.1 parts by mass of a mist suppressant, 1 part by mass of an extreme pressure agent, and 0.5 parts by mass of a metal deactivator were mixed with 100 parts by mass of a base oil to obtain an industrial oil composition.

[Examples 3-3-1 to 3-3-6]
An industrial oil composition was obtained in the same manner as in Example ^3-1 , except that a compound in which the substituents in the above formula (B) were changed to the substituents in Table 5 was used instead of 4,4'-butylidenebis(3-methyl- ⁶ -t-butylphenyl ditridecyl phosphite) (R ^b21 to R ^b24 = tridecyl groups, R ^b25 , R ^b27 = methyl groups, R b26 , R b28 = t-butyl groups, R ^b291 = hydrogen atom, R ^b292 = n-propyl group) as the neutral phosphite derivative.

[Examples 3-4-1 to 3-4-6]
An industrial oil composition was obtained in the same manner as in Example ^3-1 , except that a compound in which the substituents in the above formula (D) were changed to the substituents in Table 6 was used instead of bis(2,2,6,6-tetramethyl-1-(octyloxy)piperidin-4-yl) decanedioate (R ^d21 , R d22 = n-octyl group, R ^d23 = 1,8-octylene group) as the hindered amine compound.

[Example 3-5-1]
An industrial oil composition was obtained in the same manner as in Example 3-1, except that polyisobutylene (trade name: Struktol AM, manufactured by Sill+Seilach) was used as the mist suppressant.

[Example 3-5-2]
An industrial oil composition was obtained in the same manner as in Example 3-1, except that polyisobutylene (trade name: Struktol C, manufactured by Sill+Seilach) was used as the mist suppressant.

[Example 3-5-3]
An industrial oil composition was obtained in the same manner as in Example 3-1, except that polyisobutylene (trade name: Struktol S, manufactured by Sill+Seilach) was used as the mist suppressant.

[Example 3-6-1]
An industrial oil composition was obtained in the same manner as in Example 3-1, except that 2,5-bis(alkyldithio)-1,3,4-thiadiazole (product name: R300, manufactured by DIC Corporation) was used as the metal deactivator.

[Example 3-6-2]
An industrial oil composition was obtained in the same manner as in Example 3-1, except that 2,5-bis(alkyldithio)-1,3,4-thiadiazole (product name: RC8213, manufactured by LANXESS) was used as the metal deactivator.

[Example 3-6-3]
An industrial oil composition was obtained in the same manner as in Example 3-1, except that an alkyl thiadiazole (trade name: Hitec 4313, manufactured by Afton Chemical Co.) was used as the metal deactivator.

[Example 3-7-1]
A synthetic oil was used as the base oil, specifically, poly-α-olefin (manufactured by Chevron Phillips Chemical Company, PAO 4 cSt (grade), kinematic viscosity at 40° C. 16.8 cSt) was used as the synthetic oil.
For 100 parts by mass of this base oil, 0.1 parts by mass of 4,4'-butylidenebis(3-methyl-6-t-butylphenyl ditridecyl phosphite) as a neutral phosphite derivative and 0.2 parts by mass of octyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propanoate (CAS No. An industrial oil composition was obtained by mixing 0.5 parts by mass of bis(2,2,6,6-tetramethyl-1-(octyloxy)piperidin-4-yl) decanedioate (trade name: Irganox (registered trademark) L135, manufactured by BASF Japan Ltd.) as a hindered amine compound, 0.1 parts by mass of bis(2,2,6,6-tetramethyl-1-(octyloxy)piperidin-4-yl) decanedioate (trade name: PARATAC, manufactured by Triiso) as a mist suppressant, and 1 part by mass of lard sulfide (trade name: GS-110, manufactured by DIC Corporation), which is an inactive sulfur compound, as an extreme pressure agent.

[Example 3-7-2]
An industrial oil composition was obtained in the same manner as in Example 3-7-1, except that a sulfurized fatty acid (product name: RC2411, manufactured by LANXESS), which is an inactive sulfur compound, was used as the extreme pressure agent.

[Example 3-8-1]
An industrial oil composition was obtained in the same manner as in Example 3-1, except that the following synthetic oil was used as the base oil. That is, a mixture of poly-α-olefin (DURACYN 162, manufactured by INEOS Oligomers, kinematic viscosity at 40°C: 5.5 cSt) and poly-α-olefin (DURACYN 164, manufactured by INEOS Oligomers, kinematic viscosity at 40°C: 17.0 cSt) was used as the synthetic oil. The above mixture (whole base oil) had a kinematic viscosity at 40°C of 10 cSt.

[Example 3-8-2]
An industrial oil composition was obtained in the same manner as in Example 3-1, except that the following synthetic oil was used as the base oil: That is, poly-α-olefin (Spectrasyn 4, manufactured by Exxon Mobil Corporation, kinematic viscosity at 40° C.: 20 cSt) was used as the synthetic oil.

[Example 3-8-3]
An industrial oil composition was obtained in the same manner as in Example 3-1, except that the following synthetic oil was used as the base oil: That is, poly-α-olefin (Spectrasyn 5, manufactured by Exxon Mobil Corporation, kinematic viscosity at 40° C.: 25 cSt) was used as the synthetic oil.

[Example 3-8-4]
An industrial oil composition was obtained in the same manner as in Example 3-1, except that the following synthetic oil was used as the base oil: That is, poly-α-olefin (Ineos Oligomers, Durasin 166, kinematic viscosity at 40° C.: 31 cSt) was used as the synthetic oil.

[Example 4-1]
A mineral oil was used as the base oil. Specifically, a mineral oil belonging to Group 3 (Ultra-S3, manufactured by S-OIL Corporation, kinematic viscosity at 40° C. 14 cSt, unsaturated content 10 mass % or less) was used.
For 100 parts by mass of this base oil, 0.1 parts by mass of 4,4'-butylidenebis(3-methyl-6-t-butylphenyl ditridecyl phosphite) as a neutral phosphite derivative and 0.2 parts by mass of octyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propanoate (CAS No. An industrial oil composition was obtained by mixing 0.5 parts by mass of bis(2,2,6,6-tetramethyl-1-(octyloxy)piperidin-4-yl) decanedioate (trade name: PARATAC, manufactured by Triiso) as a hindered amine compound, 0.1 parts by mass of polyisobutylene (trade name: PARATAC, manufactured by Triiso) as a mist suppressant, 1 part by mass of sulfurized olefin (trade name: GS-440L, manufactured by DIC Corporation) as an extreme pressure agent, which is an active sulfur compound, and 0.5 parts by mass of 2,5-bis(alkyldithio)-1,3,4-thiadiazole (trade name: R100, manufactured by DIC Corporation) as a metal deactivator.

[Example 4-2]
An industrial oil composition was obtained in the same manner as in Example 4-1, except that the components were mixed in the amounts shown below: That is, 0.5 parts by mass of a neutral phosphite derivative, 0.5 parts by mass of a 2,6-di-t-butylphenol derivative, 0.1 parts by mass of a hindered amine compound, 0.1 parts by mass of a mist suppressant, 1 part by mass of an extreme pressure agent, and 0.5 parts by mass of a metal deactivator were mixed with 100 parts by mass of a base oil to obtain an industrial oil composition.

[Examples 4-3-1 to 4-3-6]
An industrial oil composition was obtained in the same manner as in Example ^4-1 , except that a compound in which the substituents in the above formula (B) were changed to the substituents in Table 7 was used instead of 4,4'-butylidenebis(3-methyl- ⁶ -t-butylphenyl ditridecyl phosphite) (R ^b21 to R ^b24 = tridecyl groups, R ^b25 , R ^b27 = methyl groups, R b26 , R b28 = t-butyl groups, R ^b291 = hydrogen atom, R ^b292 = n-propyl group) as the neutral phosphite derivative.

[Examples 4-4-1 to 4-4-6]
An industrial oil composition was obtained in the same manner as in Example ^4-1 , except that a compound in which the substituents in the above formula (D) were changed to the substituents in Table 8 was used instead of bis(2,2,6,6-tetramethyl-1-(octyloxy)piperidin-4-yl) decanedioate (R ^d21 , R d22 = n-octyl group, R ^d23 = 1,8-octylene group) as the hindered amine compound.

[Example 4-5-1]
An industrial oil composition was obtained in the same manner as in Example 4-1, except that polyisobutylene (trade name: Struktol AM, manufactured by Sill+Seilach) was used as the mist suppressant.

[Example 4-5-2]
An industrial oil composition was obtained in the same manner as in Example 4-1, except that polyisobutylene (trade name: Struktol C, manufactured by Sill+Seilach) was used as the mist suppressant.

[Example 4-5-3]
An industrial oil composition was obtained in the same manner as in Example 4-1, except that polyisobutylene (trade name: Struktol S, manufactured by Sill+Seilach) was used as the mist suppressant.

[Example 4-6-1]
An industrial oil composition was obtained in the same manner as in Example 4-1, except that 2,5-bis(alkyldithio)-1,3,4-thiadiazole (product name: R300, manufactured by DIC Corporation) was used as the metal deactivator.

[Example 4-6-2]
An industrial oil composition was obtained in the same manner as in Example 4-1, except that 2,5-bis(alkyldithio)-1,3,4-thiadiazole (product name: RC8213, manufactured by LANXESS) was used as the metal deactivator.

[Example 4-6-3]
An industrial oil composition was obtained in the same manner as in Example 4-1, except that an alkyl thiadiazole (trade name: Hitec 4313, manufactured by Afton Chemical Co.) was used as the metal deactivator.

[Example 4-7-1]
A mineral oil was used as the base oil. Specifically, a mineral oil belonging to Group 3 (Ultra-S3, manufactured by S-OIL Corporation, kinematic viscosity at 40° C. 14 cSt, unsaturated content 10 mass % or less) was used.
For 100 parts by mass of this base oil, 0.1 parts by mass of 4,4'-butylidenebis(3-methyl-6-t-butylphenyl ditridecyl phosphite) as a neutral phosphite derivative and 0.2 parts by mass of octyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propanoate (CAS No. An industrial oil composition was obtained by mixing 0.5 parts by mass of bis(2,2,6,6-tetramethyl-1-(octyloxy)piperidin-4-yl) decanedioate (trade name: Irganox (registered trademark) L135, manufactured by BASF Japan Ltd.) as a hindered amine compound, 0.1 parts by mass of bis(2,2,6,6-tetramethyl-1-(octyloxy)piperidin-4-yl) decanedioate (trade name: PARATAC, manufactured by Triiso) as a mist suppressant, and 1 part by mass of lard sulfide (trade name: GS-110, manufactured by DIC Corporation), which is an inactive sulfur compound, as an extreme pressure agent.

[Example 4-7-2]
An industrial oil composition was obtained in the same manner as in Example 4-7-1, except that a sulfurized fatty acid (product name: RC2411, manufactured by LANXESS), which is an inactive sulfur compound, was used as the extreme pressure agent.

[Example 4-8-1]
An industrial oil composition was obtained in the same manner as in Example 4-1, except that the following mineral oil was used as the base oil. That is, a mixture of a mineral oil belonging to Group 3 (Ultra-S2, manufactured by S-OIL Corporation, kinematic viscosity at 40°C of 7.62 cSt, unsaturated content of 10 mass% or less) and a mineral oil belonging to Group 3 (Ultra-S3, manufactured by S-OIL Corporation, kinematic viscosity at 40°C of 14 cSt, unsaturated content of 10 mass% or less) was used as the mineral oil. The mixture (whole base oil) had a kinematic viscosity at 40°C of 10 cSt and an unsaturated content of 10 mass% or less.

[Example 4-8-2]
An industrial oil composition was obtained in the same manner as in Example 4-1, except that the following mineral oil was used as the base oil: A mineral oil belonging to Group 3 (Ultra-S4, manufactured by S-OIL Corporation, kinematic viscosity at 40°C of 19.7 cSt, unsaturated content of 10 mass% or less) was used as the mineral oil.

[Example 4-8-3]
An industrial oil composition was obtained in the same manner as in Example 4-1, except that the following mineral oil was used as the base oil. That is, a mixture of a mineral oil belonging to Group 3 (Ultra-S4 manufactured by S-OIL Corporation, kinematic viscosity at 40°C of 19.7 cSt, unsaturated content of 10 mass% or less) and a mineral oil belonging to Group 3 (Ultra-S6 manufactured by S-OIL Corporation, kinematic viscosity at 40°C of 32.5 cSt, unsaturated content of 10 mass% or less) was used as the mineral oil. The mixture (whole base oil) had a kinematic viscosity at 40°C of 26 cSt and an unsaturated content of 10 mass% or less.

[Example 4-8-4]
An industrial oil composition was obtained in the same manner as in Example 4-1, except that the following mineral oil was used as the base oil: Group 3 mineral oil (Ultra-S2, manufactured by S-OIL Corporation, kinematic viscosity at 40°C of 7.62 cSt, unsaturated content of 10 mass% or less) was used as the mineral oil.

[Example 5-1]
A synthetic oil was used as the base oil, specifically, poly-α-olefin (manufactured by Chevron Phillips Chemical Company, PAO 4 cSt (grade), kinematic viscosity at 40° C. 16.8 cSt) was used as the synthetic oil.
100 parts by mass of this base oil was mixed with 0.1 part by mass of 4,4'-butylidenebis(3-methyl-6-t-butylphenyl ditridecyl phosphite) as a neutral phosphite derivative, 0.5 part by mass of octyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propanoate (CAS 125643-61-0, product name: Irganox (registered trademark) L135, manufactured by BASF Japan Ltd.) as a 2,6-di-t-butylphenol derivative, and 0.1 part by mass of decanedioate bis(2,2,6,6-tetramethyl-1-(octyloxy)piperidin-4-yl) as a hindered amine compound to obtain an industrial oil composition.

[Example 5-2]
A synthetic oil was used as the base oil, specifically, poly-α-olefin (manufactured by Chevron Phillips Chemical Company, PAO 4 cSt (grade), kinematic viscosity at 40° C. 16.8 cSt) was used as the synthetic oil.
With respect to 100 parts by mass of this base oil, 0.1 parts by mass of 4,4'-butylidenebis(3-methyl-6-t-butylphenyl ditridecyl phosphite) as a neutral phosphite derivative, 0.5 parts by mass of octyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propanoate (CAS 125643-61-0, product name: Irganox (registered trademark) L135, manufactured by BASF Japan Ltd.) as a 2,6-di-t-butylphenol derivative, 0.1 parts by mass of decanedioic acid bis(2,2,6,6-tetramethyl-1-(octyloxy)piperidin-4-yl) as a hindered amine compound, and 0.1 parts by mass of polyisobutylene (product name: PARATAC, manufactured by Triiso) as a mist suppressant were mixed to obtain an industrial oil composition.

[Example 5-3]
A mineral oil was used as the base oil. Specifically, a mineral oil belonging to Group 3 (Ultra-S3, manufactured by S-OIL Corporation, kinematic viscosity at 40° C. 14 cSt, unsaturated content 10 mass % or less) was used.
100 parts by mass of this base oil was mixed with 0.1 part by mass of 4,4'-butylidenebis(3-methyl-6-t-butylphenyl ditridecyl phosphite) as a neutral phosphite derivative, 0.5 part by mass of octyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propanoate (CAS 125643-61-0, product name: Irganox (registered trademark) L135, manufactured by BASF Japan Ltd.) as a 2,6-di-t-butylphenol derivative, and 0.1 part by mass of decanedioate bis(2,2,6,6-tetramethyl-1-(octyloxy)piperidin-4-yl) as a hindered amine compound to obtain an industrial oil composition.

[Example 5-4]
A mineral oil was used as the base oil. Specifically, a mineral oil belonging to Group 3 (Ultra-S3, manufactured by S-OIL Corporation, kinematic viscosity at 40° C. 14 cSt, unsaturated content 10 mass % or less) was used.
With respect to 100 parts by mass of this base oil, 0.1 parts by mass of 4,4'-butylidenebis(3-methyl-6-t-butylphenyl ditridecyl phosphite) as a neutral phosphite derivative, 0.5 parts by mass of octyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propanoate (CAS 125643-61-0, product name: Irganox (registered trademark) L135, manufactured by BASF Japan Ltd.) as a 2,6-di-t-butylphenol derivative, 0.1 parts by mass of decanedioic acid bis(2,2,6,6-tetramethyl-1-(octyloxy)piperidin-4-yl) as a hindered amine compound, and 0.1 parts by mass of polyisobutylene (product name: PARATAC, manufactured by Triiso) as a mist suppressant were mixed to obtain an industrial oil composition.

[Comparative Example 1-1]
A synthetic oil was used as the base oil, specifically, poly-α-olefin (manufactured by Chevron Phillips Chemical Company, PAO 4 cSt (grade), kinematic viscosity at 40° C. 16.8 cSt) was used as the synthetic oil.
For 100 parts by mass of this base oil, octyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propanoate (CAS No. An industrial oil composition was obtained by mixing 0.5 parts by mass of bis(2,2,6,6-tetramethyl-1-(octyloxy)piperidin-4-yl) decanedioate (trade name: PARATAC, manufactured by Triiso) as a hindered amine compound, 0.1 parts by mass of polyisobutylene (trade name: PARATAC, manufactured by Triiso) as a mist suppressant, 1 part by mass of sulfurized olefin (trade name: GS-440L, manufactured by DIC Corporation) as an extreme pressure agent, which is an active sulfur compound, and 0.5 parts by mass of 2,5-bis(alkyldithio)-1,3,4-thiadiazole (trade name: R100, manufactured by DIC Corporation) as a metal deactivator.

[Comparative Example 1-2]
A synthetic oil was used as the base oil, specifically, poly-α-olefin (manufactured by Chevron Phillips Chemical Company, PAO 4 cSt (grade), kinematic viscosity at 40° C. 16.8 cSt) was used as the synthetic oil.
With respect to 100 parts by mass of this base oil, 0.1 parts by mass of 4,4'-butylidenebis(3-methyl-6-t-butylphenyl ditridecylphosphite) as a neutral phosphite derivative, 0.1 parts by mass of bis(2,2,6,6-tetramethyl-1-(octyloxy)piperidin-4-yl) decanedioate as a hindered amine compound, 0.1 parts by mass of polyisobutylene (product name: PARATAC, manufactured by Triiso) as a mist suppressant, 1 part by mass of sulfurized olefin (product name: GS-440L, manufactured by DIC Corporation) which is an active sulfur compound as an extreme pressure agent, and 0.5 parts by mass of 2,5-bis(alkyldithio)-1,3,4-thiadiazole (product name: R100, manufactured by DIC Corporation) as a metal deactivator were mixed to obtain an industrial oil composition.

[Comparative Example 1-3]
A synthetic oil was used as the base oil, specifically, poly-α-olefin (manufactured by Chevron Phillips Chemical Company, PAO 4 cSt (grade), kinematic viscosity at 40° C. 16.8 cSt) was used as the synthetic oil.
For 100 parts by mass of this base oil, 0.1 parts by mass of 4,4'-butylidenebis(3-methyl-6-t-butylphenyl ditridecyl phosphite) as a neutral phosphite derivative and 0.2 parts by mass of octyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propanoate (CAS No. An industrial oil composition was obtained by mixing 0.5 parts by mass of 125643-61-0, trade name: Irganox (registered trademark) L135, manufactured by BASF Japan Ltd.) as a mist suppressant, 0.1 parts by mass of polyisobutylene (trade name: PARATAC, manufactured by Triiso) as a mist suppressant, 1 part by mass of a sulfurized olefin (trade name: GS-440L, manufactured by DIC Corporation) which is an active sulfur compound as an extreme pressure agent, and 0.5 parts by mass of 2,5-bis(alkyldithio)-1,3,4-thiadiazole (trade name: R100, manufactured by DIC Corporation) as a metal deactivator.

[Evaluation method and results]
(1) 300 parts were machined using a sliding headstock type CNC automatic lathe (product name: Cincom L220E-10, manufactured by Citizen Machinery Co., Ltd.) as a metalworking machine. In this case, an industrial oil composition for metalworking (the industrial oil composition prepared in Example 3-1) was applied to the parts where metalworking was to be performed. The industrial oil composition prepared in Example 1-1 was used for mechanical lubrication of the metalworking machine.
In addition, in the above, 300 parts were processed in the same manner as above, except that the industrial oil compositions prepared in Examples 3-2 to 4-8-4 and Comparative Examples 1-1 to 1-3 were used instead of the industrial oil composition prepared in Example 3-1.
After machining 300 parts, the generation of mist, oily smoke, and odor was evaluated. The generation of mist and oily smoke was evaluated by checking the fogging of the windows of the metalworking machine. If the window was not fogging, i.e., no mist or oily smoke was generated, it was marked as ◯, and if the window was fogging, i.e., there was generation of mist or oily smoke, it was marked as ×. The generation of odor was also evaluated by opening the window of the metalworking machine and checking. If there was no odor, i.e., no odor was generated, it was marked as ◯, if there was some odor, i.e., there was some odor, it was marked as △, and if there was a strong odor, i.e., there was a strong odor, it was marked as ×. The results are shown in Table 9.

From Table 9, it can be said that it is more preferable for the base oil to have a kinematic viscosity at 40°C of 13 cSt or more, since this further suppresses odor generation. In addition, the industrial oil compositions prepared in Examples 3-1 to 4-8-4 had a base oil kinematic viscosity at 40°C of 32 cSt or less, and therefore were superior in terms of ease of spraying onto the parts where metal processing is performed and ease of spreading around the cutting edge. However, if the base oil has a kinematic viscosity at 40°C of more than 32 cSt, the above-mentioned aspects may be inferior.
In addition, when the industrial oil compositions prepared in Examples 3-1 to 4-8-4 were used, the surface roughness was excellent for all the first to 300th processed parts. On the other hand, when the industrial oil compositions prepared in Comparative Examples 1-1 to 1-3 were used, the surface roughness was poor for all the first to 300th processed parts.
As mentioned above, the industrial oil composition prepared in Example 1-1 was used for mechanical lubrication of metalworking machinery. It is possible that as metalworking was carried out, the oil oozed out and mixed with the industrial oil compositions prepared in Examples 3-1 to 4-8-4. Even in this case, it is believed that the industrial oil composition prepared in Example 1-1 did not affect the generation of mist, oily smoke, or odor.

(2) 300 parts were machined using a movable headstock CNC automatic lathe (product name Cincom L220E-10, manufactured by Citizen Machinery Co., Ltd.) as a metal processing machine. In this case, an industrial oil composition for machine lubrication (industrial oil composition prepared in Example 1-1) was used for machine lubrication of the metal processing machine. In addition, a composition obtained by mixing 80% by mass of the industrial oil composition for metal processing (industrial oil composition prepared in Example 3-1) and 20% by mass of the industrial oil composition for machine lubrication (industrial oil composition prepared in Example 1-1) was applied to the part where metal processing was performed. In this way, a state in which the industrial oil composition for machine lubrication seeped out and mixed with the industrial oil composition for metal processing was simulated from the time of processing the first part.
In addition, in the above, 300 parts were processed in the same manner as above, except that the industrial oil compositions prepared in Examples 1-2 to 2-6-4 and 5-1 to 5-4 were used instead of the industrial oil composition prepared in Example 1-1.
After processing 300 parts, the generation of mist, oily smoke, and odor was evaluated. The generation of mist and oily smoke was evaluated by checking the fogging of the window of the metal processing machine. If it was not fogging, i.e., no mist or oily smoke was generated, it was marked as ◯, and if it was fogging, i.e., there was generation of mist or oily smoke, it was marked as ×. The generation of odor was also evaluated by opening the window of the metal processing machine and checking. If there was no odor, i.e., no odor was generated, it was marked as ◯, if there was some odor, i.e., there was some odor generated, it was marked as △, and if there was a strong odor, i.e., there was a strong odor generated, it was marked as ×. The results are shown in Table 10.

From Table 10, it can be seen that it is more preferable for the base oil to have a kinematic viscosity at 40° C. of 13 cSt or more, since this further suppresses the generation of odor even when the industrial oil composition for machine lubrication seeps out.
In addition, when the industrial oil compositions prepared in Examples 1-1 to 2-6-4 and 5-1 to 5-4 were used, all of the parts processed from the first part to the 300th part were excellent in surface roughness. It can be seen that even when the industrial oil composition for machine lubrication seeps out, parts with excellent surface roughness can be obtained.

Claims (7)

As a base oil, at least one selected from a synthetic oil containing an α-olefin polymer and a mineral oil having an unsaturated content of 10 mass% or less that has been subjected to hydrocracking treatment;
The antioxidant comprises a neutral phosphite derivative represented by the following formula (B), a 2,6-di-t-butylphenol derivative represented by the following formula (C), and a hindered amine compound represented by the following formula (D),
The base oil has a kinematic viscosity at 40° C. of 40 cSt or less.
Industrial oil compositions.

(In the above formula (B), R ^b21 to R ^b24 each independently represent an aliphatic hydrocarbon group having 10 to 16 carbon atoms, R ^b25 to R ^b28 each independently represent a linear or branched alkyl group having 1 to 6 carbon atoms, R ^b291 and R ^b292 each independently represent a hydrogen atom or a linear or branched alkyl group having 1 to 5 carbon atoms, and the total number of carbon atoms of R ^b291 and R ^b292 is 1 to 5.)

(In the above formula (C), R ^c1 is a linear or branched alkyl group having 1 to 12 carbon atoms.)

(In the above formula (D), R ^d21 and R ^d22 each independently represent an aliphatic hydrocarbon group having 1 to 10 carbon atoms, and R ^d23 represents a divalent aliphatic hydrocarbon group having 1 to 10 carbon atoms.) The antioxidant is contained in a total amount of 0.5 parts by mass or more and 5.0 parts by mass or less relative to 100 parts by mass of the base oil.
10. The industrial oil composition of claim 1. Further, a hydrocarbon-based polymer compound is included as a mist suppressant.
3. The industrial oil composition of claim 1 or 2. Furthermore, it contains zinc dialkyldithiophosphate as an oiliness agent,
Used for machine lubrication,
The industrial oil composition according to any one of claims 1 to 3. Further, the present invention further includes a benzotriazole derivative as a metal deactivator.
The industrial oil composition of claim 4. Further, a sulfur compound is contained as an extreme pressure agent,
Used in metal processing,
The industrial oil composition according to any one of claims 1 to 3. The sulfur compound is an active sulfur compound,
Further, the present invention further includes a thiadiazole derivative as a metal deactivator.
The industrial oil composition of claim 6.