WO2023008549A1

WO2023008549A1 - Sliding-surface lubricating oil composition

Info

Publication number: WO2023008549A1
Application number: PCT/JP2022/029255
Authority: WO
Inventors: 洋介地曳; 健志見富
Original assignee: 出光興産株式会社
Priority date: 2021-07-30
Filing date: 2022-07-29
Publication date: 2023-02-02
Also published as: JP2023020601A

Abstract

The present invention addresses the problem of providing a sliding-surface lubricating oil composition capable of inhibiting the propagation of microorganisms in a cutting oil tank. The aforementioned problem is solved by a sliding-surface lubricating oil composition containing: a base oil (A); and one or more types of amine compounds (B) selected from the group consisting of a primary amine (B1) and a secondary amine (B2), wherein the primary amine (B1) has 12 or more carbon atoms, and the secondary amine (B2) has at least one cyclic structure group.

Description

Lubricating oil composition for sliding surfaces

The present invention relates to a lubricating oil composition for sliding surfaces.

A machine tool has a sliding surface for moving a tool, a work material, etc. in any direction. A lubricating oil composition for sliding surfaces is used to facilitate sliding motion.
By the way, the lubricating oil composition for sliding surfaces is mixed in the cutting oil tank installed in the machine tool, and accelerates the deterioration of the water-soluble cutting oil. Specifically, the sliding surface lubricating oil composition mixed in the cutting oil tank serves as a nutrient source for bacteria, promoting the propagation of microorganisms in the cutting oil tank and accelerating the deterioration of the water-soluble cutting oil.

In the past, the water-soluble cutting oil and the lubricating oil composition for sliding surfaces were quickly separated to suppress the growth of microorganisms in the cutting tank and to extend the service life of the water-soluble cutting oil. (See, for example, Patent Document 1).

JP 2009-82789 A

In order to quickly separate the water-soluble cutting oil and the lubricating oil composition for sliding surfaces, an oil separation device such as an oil skimmer is required. The number of unprepared cases is increasing. Therefore, it is desired to create a lubricating oil composition for sliding surfaces that can suppress propagation of microorganisms in a cutting oil tank.

An object of the present invention is to provide a lubricating oil composition for sliding surfaces that can suppress the growth of microorganisms in a cutting oil tank.

According to the present invention, the following [1] to [4] are provided.
[1] Containing a base oil (A) and one or more amine compounds (B) selected from the group consisting of primary amines (B1) and secondary amines (B2),
The primary amine (B1) has 12 or more carbon atoms,
The lubricating oil composition for sliding surfaces, wherein the secondary amine (B2) has at least one cyclic structural group.
[2] A method of using the lubricating oil composition for sliding surfaces according to [1] above for suppressing the growth of microorganisms in a water-soluble cutting oil.
[3] After mixing the lubricating oil composition for sliding surfaces according to the above [1] into a water-soluble cutting oil, without removing the lubricating oil composition for sliding surfaces, in the water-soluble cutting oil A method for suppressing the growth of microorganisms in water-soluble cutting oil, comprising the step of holding at
[4] A step of mixing a base oil (A) with one or more amine compounds (B) selected from the group consisting of primary amines (B1) and secondary amines (B2),
The primary amine (B1) has 12 or more carbon atoms,
A method for producing a lubricating oil composition for sliding surfaces, wherein the secondary amine (B2) has at least one cyclic structural group.

According to the present invention, it is possible to provide a lubricating oil composition for sliding surfaces that can suppress the growth of microorganisms in a cutting oil tank.

The upper and lower limits of the numerical ranges described herein can be arbitrarily combined. For example, when "A to B" and "C to D" are described as numerical ranges, the numerical ranges "A to D" and "C to B" are also included in the scope of the present invention.
In addition, the numerical range "lower limit to upper limit" described in this specification means from the lower limit to the upper limit, unless otherwise specified.
In addition, in this specification, numerical values in the examples are numerical values that can be used as upper limit values or lower limit values.

[Aspect of lubricating oil composition for sliding surface]
The lubricating oil composition for sliding surfaces of the present embodiment comprises a base oil (A) and one or more amine compounds selected from the group consisting of primary amines (B1) and secondary amines (B2) ( B).
The primary amine (B1) has 12 or more carbon atoms.
And the secondary amine (B2) has at least one cyclic structural group.

The present inventors have made intensive studies to solve the above problems. As a result, they have found that a lubricating oil composition for sliding surfaces containing a specific amine compound can solve the above problems.
Although the mechanism by which the lubricating oil composition for sliding surfaces of the present invention can solve the above problems has not been clarified, it is speculated, for example, as follows. That is, it is presumed that the structure of the amine compound (B) effectively acts to reduce the activity of microorganisms and contributes to the suppression of propagation of microorganisms in the cutting oil tank. In addition, since the amine compound (B) is difficult to volatilize, it can remain in the lubricating oil composition for sliding surfaces for a long period of time. Further, the amine compound (B) can continue to remain in the sliding surface lubricating oil composition for a long period of time even after the sliding surface lubricating oil composition is mixed with the water-soluble cutting oil. It is presumed that this is because it can be demonstrated without difficulty.

In addition, since the amine compound (B) has high oil solubility, it easily remains in the lubricating oil composition for sliding surfaces even after the lubricating oil composition for sliding surfaces is mixed with the water-soluble cutting oil. Therefore, when microorganisms seek nutrients and come into contact with the sliding surface lubricating oil composition mixed in the water-soluble cutting oil, the microorganisms are exposed to the amine compound (B) present in the sliding surface lubricating oil composition. also easier to come into contact with. As a result, it is speculated that the probability of contact of the microorganisms with the amine compound (B) is improved, and the amine compound (B) reduces the activity of the microorganisms, effectively suppressing the propagation of the microorganisms. be.

In the following description, the "lubricating oil composition for sliding surfaces" is also simply referred to as "lubricating oil composition".

The lubricating oil composition of the present embodiment may be composed only of the base oil (A) and the amine compound (B), but within a range that does not significantly impair the effects of the present invention, the base oil (A) and Components other than the amine compound (B) may optionally be included.
In the lubricating oil composition of the present embodiment, the total content of the base oil (A) and the amine compound (B) is preferably 80% by mass or more, more preferably 85% by mass or more, based on the total amount of the lubricating oil composition. , more preferably 90% by mass or more, still more preferably 95% by mass or more. Also, it is preferably 100% by mass or less, more preferably less than 100% by mass, still more preferably 99.5% by mass or less, and even more preferably 99.0% by mass or less.
The upper and lower limits of these numerical ranges can be combined arbitrarily. Specifically, it is preferably 80% by mass to 100% by mass, more preferably 85% by mass to less than 100% by mass, still more preferably 90% by mass to 99.5% by mass, and even more preferably 95% by mass to 99.5% by mass. It is 0% by mass.

Each component contained in the lubricating oil composition of the present embodiment will be described in detail below.

<Base oil (A)>
The lubricating oil composition of this embodiment contains a base oil (A).
As the base oil (A), for example, one or more selected from mineral oils and synthetic oils conventionally used as base oils for lubricating oil compositions for sliding surfaces can be used without particular limitation.

Mineral oils include, for example, atmospheric residual oils obtained by atmospheric distillation of crude oils such as paraffinic crude oils, intermediate crude oils, and naphthenic crude oils; distillates obtained by vacuum distillation of these atmospheric residual oils oil; mineral oil obtained by subjecting the distillate to one or more refining treatments such as solvent deasphalting, solvent extraction, hydrocracking, solvent dewaxing, catalytic dewaxing, and hydrorefining;

Synthetic oils include, for example, polybutene, 1-octene oligomer, 1-decene oligomer and the like, hydrogenated products thereof, polyolefins such as ethylene-α-olefin copolymers; isoparaffins; Various esters; Various ethers such as polyphenyl ether; Polyalkylene glycol; Alkylbenzene; GTL base oil and the like can be mentioned.

One type of mineral oil may be used alone, or two or more types may be used in combination. Synthetic oils may also be used singly or in combination of two or more. Also, one or more mineral oils and one or more synthetic oils may be used in combination.

In the lubricating oil composition of the present embodiment, the base oil (A) preferably contains mineral oil. The mineral oil content is preferably 50% by mass or more, more preferably 60% by mass or more, still more preferably 70% by mass or more, still more preferably 80% by mass or more, and still more preferably 80% by mass or more, based on the total amount of the base oil (A). It is preferably 90% by mass or more, more preferably 95% by mass or more. Also, it is preferably 100% by mass or less, more preferably 99.5% by mass or less.

In addition, when the base oil (A) contains mineral oil, the mineral oil may be one or more selected from mineral oils classified into Groups I, II, and III in the American Petroleum Institute (API) category. , Group I and II mineral oils, or group I mineral oils.
When the base oil (A) contains a mineral oil classified into Group I in the API category, the content of the mineral oil classified into Group I is based on the total amount of the base oil (A), preferably 50% by mass or more, more It is preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, still more preferably 90% by mass or more, and still more preferably 95% by mass or more. Also, it is preferably 100% by mass or less, more preferably 99.5% by mass or less.

Moreover, from the viewpoint of facilitating the imparting of oil film retention (stickiness) to sliding portions, the base oil (A) preferably contains a polyolefin. The polyolefin content is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, and still more preferably 0.3% by mass or more, based on the total amount of the base oil (A). Also, it is preferably 2.0% by mass or less, more preferably 1.5% by mass or less, and even more preferably 1.0% by mass or less.
In addition, the polyolefin preferably has a kinematic viscosity of 2,000 mm ² /s to 4,000 mm ² /s at 100° C. from the viewpoint of making it easier to impart oil film retention (sticking property) to sliding parts. It is more preferably 2,000 mm ² /s to 3,500 mm ² /s.
Among polyolefins, polybutene is preferable from the viewpoint of making it easier to impart oil film retention (stickiness) to sliding portions.

In addition, the base oil (A) preferably has a kinematic viscosity at 40° C. (hereinafter also referred to as “40° C. kinematic viscosity”) of 10 mm ² /s to 220 mm ² /s.
When the 40° C. kinematic viscosity of the base oil (A) is 220 mm ² /s or less, it is easy to improve the sliding properties of the lubricating oil composition at medium sliding speed and high sliding speed.
Moreover, when the 40° C. kinematic viscosity of the base oil (A) is 10 mm ² /s or more, the coefficient of friction of the lubricating oil composition at a low sliding speed can be more easily reduced.
From the above viewpoint, the 40° C. kinematic viscosity of the base oil (A) is more preferably 15 mm ² /s or more, still more preferably 20 mm ² /s or more, still more preferably 25 mm ² /s or more, and more It is preferably 150 mm ² /s or less, more preferably 90 mm ² /s or less, still more preferably 75 mm ² /s or less.
The upper and lower limits of these numerical ranges can be combined arbitrarily. Specifically, it is more preferably 15 mm ² /s to 150 mm ² /s, still more preferably 20 mm ² /s to 90 mm ² /s, still more preferably 25 mm ² /s to 75 mm ² /s.
As used herein, the 40° C. kinematic viscosity of base oil (A) means a value measured according to JIS K2283:2000.
In addition, when the base oil (A) is a mixed base oil containing two or more kinds of base oils, the 40° C. kinematic viscosity of the mixed base oil is preferably within the above range.

In the present embodiment, the content of the base oil (A) in the lubricating oil composition is preferably 70.0% by mass or more, more preferably 80.0% by mass or more, based on the total amount of the lubricating oil composition. Preferably, it is 90.0% by mass or more. Also, it is preferably 99.0% by mass or less, more preferably 98.5% by mass or less, and still more preferably 98.0% by mass or less.
The upper and lower limits of these numerical ranges can be combined arbitrarily. Specifically, it is preferably 70.0% by mass to 99.0% by mass, more preferably 80.0% by mass to 98.5% by mass, and still more preferably 90.0% by mass to 98.0% by mass. .

<Amine compound (B)>
The lubricating oil composition of this embodiment contains an amine compound (B).
The amine compound (B) is one or more selected from the group consisting of primary amines (B1) and secondary amines (B2).
The primary amine (B1) has 12 or more carbon atoms.
The secondary amine (B2) has at least one cyclic structural group.

In the present embodiment, the primary amine (B1) may be used singly or in combination of two or more. The secondary amine (B2) may also be used singly or in combination of two or more. Also, one or more primary amines (B1) and one or more secondary amines (B2) may be used in combination.

The primary amine (B1) and secondary amine (B2) are described in detail below.

(Primary amine (B1))
The primary amine (B1) has 12 or more carbon atoms.
When the number of carbon atoms of the primary amine (B1) is less than 12, the primary amine (B1) is easily volatilized and cannot be retained in the lubricating oil composition for a long period of time, resulting in propagation of microorganisms. The effect of suppressing is reduced.

The hydrocarbon group bonded to the nitrogen atom of the primary amine (B1) is not particularly limited as long as it has 12 or more carbon atoms. Examples of hydrocarbon groups having 12 or more carbon atoms include alkyl groups, alkenyl groups, cycloalkyl groups, alkylcycloalkyl groups, cycloalkylalkyl groups, alkylcycloalkylalkyl groups, cycloalkenyl groups, alkylcycloalkenyl groups, and cycloalkenyl groups. Alkyl groups, alkylcycloalkenylalkyl groups, aryl groups, alkylaryl groups, arylalkyl groups, alkylarylalkyl groups and the like can be mentioned.
Alkyl groups and alkenyl groups may be linear or branched.

Here, the carbon number of the hydrocarbon group bonded to the nitrogen atom of the primary amine (B1) is preferably 14 or more, more preferably 14 or more, more preferably 16 or more. In addition, from the viewpoint of facilitating improvement in the effect of inhibiting the growth of microorganisms, it is preferably 28 or less, more preferably 24 or less.

(Secondary amine (B2))
The secondary amine (B2) has at least one cyclic structural group.
When the secondary amine (B2) does not have a cyclic structural group, the effect of reducing the activity of microorganisms by the secondary amine (B2) is insufficient, making it difficult to suppress the growth of microorganisms.

The structure of the secondary amine (B2) is not particularly limited as long as it has at least one cyclic structural group.
Specifically, the secondary amine (B2) has a cyclic structure group and a group having no cyclic structure, and the cyclic structure group and the group having no cyclic structure are each bonded to a nitrogen atom. good too. Alternatively, the secondary amine (B2) may have two independent cyclic structural groups, each of which may be bonded to a nitrogen atom.
The cyclic structure group possessed by the secondary amine (B2) includes, for example, a cycloalkyl group, an alkylcycloalkyl group, a cycloalkylalkyl group, an alkylcycloalkylalkyl group, a cycloalkenyl group, an alkylcycloalkenyl group, and a cycloalkenylalkyl group. , an alkylcycloalkenylalkyl group, an aryl group, an alkylaryl group, an arylalkyl group, and an alkylarylalkyl group.
Examples of groups having no cyclic structure that the secondary amine (B2) may have include chain aliphatic hydrocarbon groups such as alkyl groups and alkenyl groups. The chain aliphatic hydrocarbon group may be linear or branched.

The carbon number of the secondary amine (B2) is preferably 10 or more, more preferably 12 or more, from the viewpoint of making it easier to suppress volatilization of the secondary amine (B2). In addition, from the viewpoint of facilitating the improvement of the effect of inhibiting the growth of microorganisms, it is preferably 30 or less, more preferably 28 or less.

Here, from the viewpoint of making it easier to improve the effect of suppressing the growth of microorganisms by the secondary amine (B2), the nitrogen atom of the secondary amine (B2) has two independent cyclic structural groups (cyclic carbonization hydrogen groups) are preferably bonded to each other.
Specifically, the secondary amine (B2) is preferably a compound represented by the following general formula (b2).

In general formula (b2) above, R ¹ and R ² are each independently a substituted or unsubstituted monovalent cyclic hydrocarbon group having 5 to 10 ring-forming carbon atoms.

Examples of monovalent cyclic hydrocarbon groups having 5 to 10 ring-forming carbon atoms include cycloalkyl groups such as cyclopentyl, cyclohexyl, cyclopentyl, cyclooctyl, cyclononyl, cyclodecyl, and decahydronaphthyl groups. cyclohexyl groups such as cyclopentenyl group, cyclohexenyl group, cyclopentenyl group, cyclooctenyl group, cyclononenyl group, cyclodecenyl group, and decahydronaphthenyl group; and aryl groups such as phenyl group and naphthyl group.
Among these, a cycloalkyl group is preferable from the viewpoint of making it easier to further improve the effect of suppressing the growth of microorganisms by the secondary amine (B2).
In addition, the monovalent cyclic hydrocarbon groups that can be selected as R ¹ and R ² may be the same or different. From the viewpoint of facilitating improvement, it is preferable that both R 1 and R 2 are the same, and more preferably both R ¹ and R ² are cycloalkyl groups.

Moreover, the monovalent cyclic hydrocarbon group may have a substituent or may be unsubstituted.
When having a substituent, the substituent may be, for example, an alkyl group having 1 to 4 carbon atoms or an alkenyl group having 1 to 4 carbon atoms. The alkyl group and alkenyl group may be linear or branched. When the monovalent cyclic hydrocarbon group has a substituent, the number of substituents may be one, or two or more. When the monovalent cyclic hydrocarbon group has two or more substituents, the two or more substituents may be the same or different.

In general formula (b2) above, L ¹ and L ² are each independently a single bond or an alkylene group having 1 to 4 carbon atoms.
The term “single bond” as used herein means that the nitrogen atom and R ¹ are directly bonded and that the nitrogen atom and R ² are directly bonded in the general formula (b2).
From the viewpoint of further improving the effect of suppressing the growth of microorganisms by the secondary amine (B2), L ¹ and L ² are each independently a single bond or an alkylene group having 1 to 2 carbon atoms. A single bond or an alkylene group having 1 carbon atom is preferred, and a single bond is even more preferred.
In addition, the groups that can be selected as L ¹ and L ² may be the same or different. Preferably they are the same, and more preferably both L ¹ and L ² are single bonds.

Here, from the viewpoint of further improving the microbial growth inhibitory effect, a more preferred embodiment of the secondary amine (B2) is a compound represented by the following general formula (b2x).

In general formula (b2x) above, R ¹¹ and R ¹² are each independently an alkyl or alkenyl group having 1 to 4 carbon atoms.
m is an integer from 0 to 5; When m is 2 to 5, multiple R ¹¹ may be the same or different.
n is an integer from 0 to 5; When n is 2 to 5, multiple R ¹² may be the same or different.

The number of carbon atoms in the alkyl and alkenyl groups that can be selected as R ¹¹ and R ¹² is preferably 1-3, more preferably 1-2, and still more preferably 1.

Also, the value of m is preferably 0 to 3, more preferably 0 to 2, still more preferably 0 to 1, and even more preferably 0.

Also, the value of n is preferably 0 to 3, more preferably 0 to 2, even more preferably 0 to 1, and even more preferably 0.

<Content of amine compound (B)>
In the lubricating oil composition of the present embodiment, the content of the amine compound (B) is preferably 0.1% by mass or more and 5.0% by mass or less based on the total amount of the lubricating oil composition.
When the content of the amine compound (B) is 0.1% by mass or more, the effect of suppressing the growth of microorganisms is likely to be exhibited.
Moreover, when the content of the amine compound (B) is 5.0% by mass or less, it is easy to suppress deterioration in oxidation stability due to excessive addition of the amine compound (B).
From the above viewpoint, the content of the amine compound (B) is more preferably 0.3% by mass or more, still more preferably 0.5% by mass or more, and even more preferably 0.7% by mass or more. Also, it is more preferably 4.0% by mass or less, still more preferably 3.0% by mass or less, and even more preferably 2.0% by mass or less. The upper and lower limits of these numerical ranges can be combined arbitrarily. Specifically, it is more preferably 0.3% by mass to 4.0% by mass, still more preferably 0.5% by mass to 3.0% by mass, and even more preferably 0.7% by mass to 2.0% by mass. is.

<Physical property values of amine compound (B)>
(Amount of volatilization)
The amine compound (B) has a volatilization amount (60° C.×1 hour) measured by the method described in Examples below, which is preferably 10% or less, more preferably 7% or less, and still more preferably 5% or less. .

<Other components other than base oil (A) and amine compound (B)>
The lubricating oil composition of the present embodiment may contain other components other than the base oil (A) and the amine compound (B) within a range that does not significantly impair the effects of the present invention. It doesn't have to be.
Examples of such other components include oiliness agents, antioxidants, rust inhibitors, metal deactivators, corrosion inhibitors, extreme pressure agents, antifoaming agents, demulsifiers, and pour point depressants. .
These may be used individually by 1 type, and may be used in combination of 2 or more type.
In the lubricating oil composition of the present embodiment, the total content of other components is preferably 0% by mass to 15% by mass, more preferably 0.1% by mass to 10% by mass, based on the total amount of the lubricating oil composition. , more preferably 0.5% by mass to 5% by mass.

(oily agent)
Examples of oiliness agents include saturated aliphatic monocarboxylic acids and unsaturated aliphatic monocarboxylic acids such as stearic acid and oleic acid; polymerized fatty acids such as dimer acid and hydrogenated dimer acid; ricinoleic acid and 12-hydroxystearic acid; aliphatic saturated and unsaturated monoalcohols such as lauryl alcohol and oleyl alcohol; aliphatic saturated and unsaturated monocarboxylic acid amides such as lauric amide and oleic amide; glycerin and sorbitol, etc. and a partial ester of a polyhydric alcohol with an aliphatic saturated monocarboxylic acid or an aliphatic unsaturated monocarboxylic acid.
Oily agents may be used singly or in combination of two or more.
The content of the oiliness agent is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, based on the total amount of the lubricating oil composition. Also, it is preferably 10% by mass or less, more preferably 5% by mass or less.

(Antioxidant)
Examples of antioxidants include phenol-based antioxidants, amine-based antioxidants, sulfur-based antioxidants, and the like.
An antioxidant may be used individually by 1 type, and may be used in combination of 2 or more type.
The content of the antioxidant is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, based on the total amount of the lubricating oil composition. Also, it is preferably 5% by mass or less, more preferably 3% by mass or less.

(Metal deactivator)
Examples of metal deactivators include benzotriazole-based, benzimidazole-based, benzothiazole-based, thiadiazole-based, and dimercaptothiazole-based agents.
The metal deactivators may be used singly or in combination of two or more.
The content of the metal deactivator is preferably 0.005% by mass or more, more preferably 0.01% by mass or more, based on the total amount of the lubricating oil composition. Also, it is preferably 5% by mass or less, more preferably 3% by mass or less.

(corrosion inhibitor)
Corrosion inhibitors include, for example, alkanolamines, amides, carboxylic acids, and the like.
A corrosion inhibitor may be used individually by 1 type, and may be used in combination of 2 or more type.
The content of the corrosion inhibitor is preferably 0.005% by mass or more, more preferably 0.01% by mass or more, based on the total amount of the lubricating oil composition. Also, it is preferably 5% by mass or less, more preferably 3% by mass or less.

(extreme pressure agent)
Examples of extreme pressure agents include phosphorus-based extreme pressure agents such as phosphates, acid phosphates, phosphites, acid phosphites, and amine salts thereof. phenyl phosphate and the like.
Other extreme pressure agents include metal salts of carboxylic acids. The carboxylic acid metal salt referred to herein is preferably a carboxylic acid having 3 to 60 carbon atoms, more preferably a metal salt of a fatty acid having 3 to 30 carbon atoms, more preferably a metal salt of a fatty acid having 12 to 30 carbon atoms. is salt. Further, metal salts of dimer acids, trimer acids, and dicarboxylic acids having 3 to 30 carbon atoms of the above fatty acids can be mentioned. Among these metal salts of carboxylic acids, fatty acids having 12 to 30 carbon atoms and metal salts of dicarboxylic acids having 3 to 30 carbon atoms are preferable. The metal constituting the metal salt is preferably an alkali metal or an alkaline earth metal, more preferably an alkali metal.
Furthermore, examples of extreme pressure agents other than those described above include sulfur-based extreme pressure agents such as dihydrocarbyl polysulfides, thiocarbamates, thioterpenes, and dialkylthiodipropionates.
The extreme pressure agents may be used singly or in combination of two or more.
The content of the extreme pressure agent is preferably 0.05% by mass or more, more preferably 0.1% by mass or more, based on the total amount of the lubricating oil composition. Also, it is preferably 10% by mass or less, more preferably 5% by mass or less.

(Antifoaming agent)
Examples of antifoaming agents include silicone antifoaming agents such as silicone oils, fluorinated silicone antifoaming agents such as fluorosilicone oils, and polyacrylates.
An antifoaming agent may be used individually by 1 type, and may be used in combination of 2 or more type.
The content of the antifoaming agent is preferably 0.0001% by mass or more, more preferably 0.0005% by mass or more, based on the total amount of the lubricating oil composition. Also, it is preferably 0.5% by mass or less, more preferably 0.01% by mass or less.

(Anti-emulsifier)
Examples of demulsifiers include polyalkylene glycol and derivatives thereof; surfactants such as anionic surfactants, cationic surfactants and nonionic surfactants; and the like.
An anti-emulsifier may be used individually by 1 type, and may be used in combination of 2 or more type.
The content of the demulsifier is, for example, 0.001% by mass or more and 0.5% by mass or less based on the total amount of the lubricating oil composition.
However, since the lubricating oil composition of the present embodiment holds the lubricating oil composition in the water-soluble cutting oil to suppress the propagation of microorganisms, it is not necessary to improve the separability from the water-soluble cutting oil. Therefore, the content of demulsifier may be low, preferably less than 0.001% by weight, more preferably less than 0.0001% by weight.

(Pour point depressant)
Examples of pour point depressants include ethylene-vinyl acetate copolymers, condensates of chlorinated paraffin and naphthalene, condensates of chlorinated paraffin and phenol, polymethacrylates (PMA; polyalkyl (meth)acrylates etc.), polyvinyl acetate, polyalkylstyrene and the like.
Pour point depressants may be used alone or in combination of two or more.
The content of the pour point depressant is preferably 0.05% by mass or more, more preferably 0.1% by mass or more, based on the total amount of the lubricating oil composition. Also, it is preferably 1% by mass or less, more preferably 0.5% by mass or less.

[Method for producing lubricating oil composition]
The method for producing the lubricating oil composition of the present embodiment is not particularly limited.
For example, the method for producing a lubricating oil composition of the present embodiment includes a base oil (A), and one or more amine compounds selected from the group consisting of primary amines (B1) and secondary amines (B2) (B), wherein the primary amine (B1) has 12 or more carbon atoms, and the secondary amine (B2) has at least one cyclic structural group. A method for producing a composition.
The method for mixing the above components is not particularly limited, but for example, a method comprising the step of blending the base oil (A) with the amine compound (B) can be mentioned. When a component other than the base oil (A) and the amine compound (B) is blended, the other component may be blended together with the amine compound (B) or separately. Further, each component may be blended after adding a diluent oil or the like to form a solution (dispersion). After blending each component, it is preferable to stir and uniformly disperse the components by a known method.

[Use of lubricating oil composition]
The lubricating oil composition of this embodiment can suppress the propagation of microorganisms in the cutting oil tank.
Accordingly, the present invention provides the following methods of use.
- A method of using the lubricating oil composition of the present embodiment for inhibiting the propagation of microorganisms in a water-soluble cutting oil.
Further, according to the present invention, the following method is provided.
- After mixing the lubricating oil composition of the present embodiment into the water-soluble cutting oil, the water-soluble A method for suppressing the growth of microorganisms in a toxic cutting oil.

[Machine Tools]
The lubricating oil composition of the present embodiment can be suitably used as a lubricating oil composition for sliding surfaces of machine tools.
Machine tools that use the lubricating oil composition of the present embodiment include, for example, NC (Numerical Control Machine) machine tools, machining centers, grinding machines, CNC (Computerized Numerical Control), multitasking machines and the like.
The lubricating oil composition of this embodiment can suppress the propagation of microorganisms in the cutting oil tank. Therefore, it is not necessary to separate the lubricating oil composition of the present embodiment from the water-soluble cutting oil in the cutting tank with a device such as an oil skimmer.
Therefore, according to the lubricating oil composition of the present embodiment, a machine tool having a mechanism for supplying the lubricating oil composition to the sliding surface is provided. Examples of such machine tools include NC (Numerical Control Machine) machine tools, machining centers, grinding machines, CNC (Computerized Nume), multitasking machines, and the like. A system including a machine tool having a mechanism for supplying the lubricating oil composition to a sliding surface may not be equipped with an oil separator such as an oil skimmer.

[One aspect of the provided invention]
According to one aspect of the present invention, the following [1] to [6] are provided.
[1] Containing a base oil (A) and one or more amine compounds (B) selected from the group consisting of primary amines (B1) and secondary amines (B2),
The primary amine (B1) has 12 or more carbon atoms,
The lubricating oil composition for sliding surfaces, wherein the secondary amine (B2) has at least one cyclic structural group.
[2] The slide according to [1] above, wherein the secondary amine (B2) has two independent cyclic structural groups, and the two cyclic structural groups are each bonded to a nitrogen atom. A lubricating oil composition for surfaces.
[3] The above [1] or [2], wherein the content of the amine compound (B) is 0.1% by mass or more and 5.0% by mass or less based on the total amount of the lubricating oil composition for sliding surfaces. ] Lubricating oil composition for sliding surfaces according to .
[4] A method of using the lubricating oil composition for sliding surfaces according to any one of [1] to [3] above for suppressing the growth of microorganisms in water-soluble cutting oil.
[5] After mixing the lubricating oil composition for sliding surfaces according to any one of the above [1] to [3] with water-soluble cutting oil, without removing the lubricating oil composition for sliding surfaces and a method for inhibiting propagation of microorganisms in water-soluble cutting oil, comprising the step of holding in said water-soluble cutting oil.
[6] A step of mixing a base oil (A) with one or more amine compounds (B) selected from the group consisting of primary amines (B1) and secondary amines (B2),
The primary amine (B1) has 12 or more carbon atoms,
A method for producing a lubricating oil composition for sliding surfaces, wherein the secondary amine (B2) has at least one cyclic structural group.

The present invention will be specifically described by the following examples, but the present invention is not limited to the following examples.

[Example 1 and Comparative Examples 1 to 6]
Raw materials used for preparing the sliding surface lubricating oil compositions of Example 1 and Comparative Examples 1 to 6 are shown below.

<Base oil (A)>
・"Mineral oil 1": Mineral oil classified as Group I in the API category (40°C kinematic viscosity: 29 mm ² /s)
・"Mineral oil 2": Mineral oil classified as Group I in the API category (40°C kinematic viscosity: 97 mm ² /s)
・“Synthetic oil”: polybutene (100° C. kinematic viscosity: 2850 mm ² /s)

<Amine compound (B)>
- "Dicyclohexylamine": A compound corresponding to a secondary amine (B2) having at least one cyclic structural group, wherein n = 0 and m = 0 in the above general formula (b2x).

<Amine compound (B')>
・"Cyclohexylamine": primary amine having less than 12 carbon atoms (6 carbon atoms, with cyclic structural group)
・ “n-hexylamine”: a primary amine having less than 12 carbon atoms (6 carbon atoms, no cyclic structural group)
・ “Di-n-hexylamine”: a secondary amine having no cyclic structural group (12 carbon atoms)
- "N-methyldicyclohexylamine": tertiary amine (13 carbon atoms, with cyclic structural group)
・ “Trihexylamine”: tertiary amine (18 carbon atoms, no cyclic structural group)

<Other additives>
・Sliding surface oil package additives: amine-based antioxidants, sulfur-based extreme pressure agents, thiophosphates, fatty acid salts, rust inhibitors, diluent oils

The above raw materials were sufficiently mixed in the blending amounts (% by mass) shown in Table 1 to prepare lubricating oil compositions for sliding surfaces of Example 1 and Comparative Examples 1 to 6, respectively.

[Methods for measuring or evaluating various physical properties]
(1) 40° C. Kinematic Viscosity and 100° C. Kinematic Viscosity The 40° C. kinematic viscosity and 100° C. kinematic viscosity of the base oil were measured according to JIS K2283:2000.

(2) Amount of volatilized amine compound 20 g of an amine compound was placed in a 120 mL container and weighed (initial weight). Next, the amine compound placed in the container was heated to 60° C. and held for 1 hour, and then weighed (post-test weight).
Then, the volatilization amount of the amine compound (60° C., 1 hour) was calculated by the following formula (f1).
Amount of volatilization (unit: %) = {(initial weight) - (weight after test)} x 100/(initial weight) (f1)
The larger the volatilization amount of the amine compound, the easier it is for the amine compound to volatilize. Conversely, the smaller the volatilization amount of the amine compound, the more difficult it is for the amine compound to volatilize.
In this example, samples with a volatilization amount of the amine compound of 10% or less were judged to be acceptable.

(3) Spoilage Test Into an Erlenmeyer flask were placed 100 mL of a 30-fold diluted emulsion-type water-soluble cutting oil and 10 mL each of the sliding surface lubricating oil compositions of Example 1 and Comparative Examples 1-6.
Then, 3 g of Cast Iron Chips specified by ASTM D4627, 1 mL of putrefaction liquid A and 0.2 mL of putrefaction liquid B shown below were added to the Erlenmeyer flask, and cultured with shaking at 30° C. and 150 rpm. started. During the culture period, putrefaction liquid A (1 mL) and putrefaction liquid B (0.2 mL) were additionally added every 7 days. The viable count of the liquid in the Erlenmeyer flask was measured immediately before adding the putrefactive liquid A and the putrefactive liquid B every 7 days, and the life span was determined when the viable count reached 10 ⁷ CFU/mL.
The longer the life, the higher the effect of reducing microbial activity, and the easier it is to suppress the growth of microorganisms in the cutting tank. Conversely, the shorter the life, the lower the effect of reducing microbial activity, and the more difficult it is to suppress the growth of microorganisms in the cutting tank.
In this example, lubricating oil compositions for sliding surfaces that took 3 weeks or longer to reach 10 ⁷ CFU/mL in viable cell count were accepted.
The details of putrefactive liquids A and B and the method for measuring the number of viable bacteria are shown below.

(Details of putrid liquids A and B)
・ Putrid Liquid A
Merck's "Tryptic Soy Broth 105459" was added to putrefied and degraded emulsion-type water-soluble cutting fluid, which was then activated by shaking culture for 24 hours.
・ Putrefactive liquid B
To a medium prepared by adding tartaric acid to Sigma Aldrich's "Potato Dextrose Broth P6685" and adjusting the pH to 3.5, putrefactive and deteriorated emulsion type water-soluble cutting fluid was added, and this was cultured with shaking for 48 hours. The activated one was used.
The shaking culture conditions for preparing putrefactive liquids A and B were 30° C. and 150 rpm in an environment containing 3 g of Cast Iron Chips defined by ASTM D4627.

(Method for measuring the number of viable bacteria)
The number of viable bacteria in 1 mL was determined using Aidian's "Easicult® Combi" TTC medium for bacterial count, and lifespan was determined based on the viable bacterial count.
Yeast and fungi were also measured using Rose Bengal medium, and it was confirmed that the growth of yeast and fungi was suppressed within the life span based on the number of viable bacteria.

Table 1 shows the results.
In Table 1, since the lubricating oil composition for sliding surfaces of Comparative Example 1 did not contain an amine compound, the volatilization amount of the amine compound was not measured.

Table 1 shows the following.
From the results shown in Example 1, it can be seen that the lubricating oil composition for sliding surfaces containing the amine compound (B) is excellent in the effect of suppressing the growth of microorganisms and is difficult to volatilize.
On the other hand, the primary amines having less than 12 carbon atoms contained in the lubricating oil compositions for sliding surfaces of Comparative Examples 2 and 3 are easily volatilized, and are contained in the lubricating oil compositions for sliding surfaces. It turns out that you can't stay for the long term.
In addition, as in Comparative Example 4, it can be seen that the lubricating oil composition for sliding surfaces containing a secondary amine having no cyclic structural group has an insufficient effect of suppressing the propagation of microorganisms.
Moreover, as in Comparative Examples 5 and 6, it can be seen that the tertiary amine-containing lubricating oil composition for sliding surfaces also has an insufficient effect of suppressing the growth of microorganisms.

Claims

Containing a base oil (A) and one or more amine compounds (B) selected from the group consisting of primary amines (B1) and secondary amines (B2),
The primary amine (B1) has 12 or more carbon atoms,
The lubricating oil composition for sliding surfaces, wherein the secondary amine (B2) has at least one cyclic structural group.
The lubricating oil for sliding surfaces according to claim 1, wherein the secondary amine (B2) has two independent cyclic structural groups, and the two cyclic structural groups are each bonded to a nitrogen atom. Composition.
The sliding according to claim 1 or 2, wherein the content of the amine compound (B) is 0.1% by mass or more and 5.0% by mass or less based on the total amount of the lubricating oil composition for sliding surfaces. A lubricating oil composition for surfaces.
A method of using the lubricating oil composition for sliding surfaces according to any one of claims 1 to 3 for suppressing the growth of microorganisms in water-soluble cutting oil.
After mixing the sliding surface lubricating oil composition according to any one of claims 1 to 3 into a water-soluble cutting oil, without removing the sliding surface lubricating oil composition, the water-soluble A method for inhibiting propagation of microorganisms in water-soluble cutting oil, comprising a step of holding in cutting oil.
A step of mixing a base oil (A) with one or more amine compounds (B) selected from the group consisting of primary amines (B1) and secondary amines (B2),
The primary amine (B1) has 12 or more carbon atoms,
A method for producing a lubricating oil composition for sliding surfaces, wherein the secondary amine (B2) has at least one cyclic structural group.