WO2015053147A1

WO2015053147A1 - Lubricating oil composition for metal working

Info

Publication number: WO2015053147A1
Application number: PCT/JP2014/076276
Authority: WO
Inventors: 鉄平辻本; 八木下　和宏; 紀夫千本木; 智宏高木
Original assignee: Ｊｘ日鉱日石エネルギー株式会社
Priority date: 2013-10-08
Filing date: 2014-10-01
Publication date: 2015-04-16
Also published as: CN105637076A; CN105637076B

Abstract

　Provided is a lubricating oil composition for metal working, with which it is possible to achieve improved working efficiency and improved tool life, and which is an environmentally-friendly product containing no chlorine, wherein the lubricating oil composition for metal working contains a lubricating oil base oil, (A) a sulfate ester represented by a predetermined formula and/or a dialkylpolysulfide in which 50 mol% of the sulfur has 4 or more crosslinks, and (B) a metallic cleaner having a metal ratio of 6 or greater.

Description

Lubricating oil composition for metal working

The present invention relates to a lubricating oil composition for metalworking that does not contain chlorine.

Conventionally, various compositions have been used in metal working such as cutting and plastic working, and chlorine-based extreme pressure agents that are excellent in workability improvement effect and inexpensive have been used particularly frequently as metal working fluids.
However, in recent years, lubricating oils containing chlorinated extreme pressure agents have been pointed out as problems such as generation of dioxins during incineration, corrosion and damage of incinerators, and some organochlorine compounds are carcinogenic. It has been reported to have Accordingly, there is a need for the development of metalworking oils that do not contain chlorine. As metal processing oils that do not contain chlorine, those using sulfur base materials such as polysulfide, sulfurized fats and oils, calcium sulfonate, ZnDTP, and phosphorus base materials such as phosphate esters have been conventionally known (the following patent documents). 1-5).
However, these lubricating oil compositions do not have sufficient machining performance. Due to recent material hardness, high plasticity, and high machining efficiency, the cutting tool life and machining accuracy are reduced, and plastic working However, problems such as material breakage and tool breakage have occurred.

Japanese Patent Laid-Open No. 6-313182 JP-A-6-330076 Japanese Patent Laid-Open No. 10-226795 JP 2004-059658 A JP 2003-073684 A

The present invention has been made in view of such circumstances, and provides a non-chlorine-based lubricating oil composition for metal processing that is excellent in processing performance and can be suitably used as a processing oil that can be applied under difficult processing conditions. The purpose is to do.

As a result of intensive studies on the above problems, the inventors of the present invention have obtained a lubricating oil composition obtained by blending a lubricating base oil with a sulfur-containing compound having a specific structure [A] and a metallic detergent having a specific metal ratio [B]. The present inventors have found that the problem can be solved by a product, and have completed the present invention.

That is, the present invention relates to a lubricating base oil, [A1] a dialkyl polysulfide in which the number of sulfur crosslinks of 4 or more occupies 50 mol% or more, and [A2] general formula (1) and / or formula (2) It is a lubricating oil composition for metal working containing a sulfur-containing compound selected from the sulfurized esters represented, and [B] a metal-based detergent having a metal ratio of 6 or more.

(Wherein R ¹ and R ² represent hydrogen or a hydrocarbyl group having 1 to 24 carbon atoms. A, b, c and d are each independently an integer of 4 or more, and the sum of a and b is 10 to 16) The sum of c and d is 9-15.)

In the present invention, [A2] further contains a sulfide ester represented by [A3] general formula (3), and the mass ratio of [A3] to [A2] ([A3] / [A2]) Satisfying 0.8 to 20, and the total content of [A2] and [A3] is 1 to 50% by mass based on the total amount of the lubricating oil composition. .

(Wherein n represents a positive number of 1 or more, R ³ and R ⁴ each independently represent hydrogen or a hydrocarbyl group having 1 to 24 carbon atoms, and a1, b1, a2, and b2 each independently represent 3 or more. (The sum of a1 and b1 and the sum of a2 and b2 are 8 to 14, respectively.)

Further, the present invention is the above-described lubricating oil composition for metal working, wherein the content of the metal detergent is 0.1 to 10% by mass based on the total amount of the lubricating oil composition.
The present invention also provides the metal processing lubricant composition, wherein the metal-based detergent is calcium sulfonate.

According to the present invention, there is provided a lubricating oil composition for metal working that does not contain a chlorine-based extreme pressure agent, has few environmental problems, is excellent in processing performance, and can be applied under difficult processing conditions. *

Hereinafter, the present invention will be described in detail.

The lubricating oil composition for metal processing of the present invention contains a lubricating base oil, [A] a sulfur-containing compound having a specific structure, and [B] a metallic detergent having a metal ratio of 6 or more.

As the lubricating base oil of the lubricating oil composition of the present invention, mineral oil, synthetic oil and fats and oils are used, and these may be a mixture.

As mineral oil, for example, a lubricating oil fraction obtained by subjecting crude oil to atmospheric distillation and vacuum distillation is subjected to solvent removal, solvent extraction, hydrocracking, solvent dewaxing, catalytic dewaxing, catalytic dewaxing, hydrogenation. Examples thereof include paraffinic mineral oil or naphthenic mineral oil that is refined by appropriately combining one or more purification treatments such as purification, sulfuric acid washing, and clay treatment.

Synthetic oils include, for example, propylene oligomer, polybutene, polyisobutylene, 1-octene oligomer, 1-decene oligomer, ethylene and propylene co-oligomer, ethylene and 1-octene co-oligomer, and ethylene and 1-decene. Poly α-olefin (PAO) such as co-oligomer or hydride thereof; isoparaffin; alkyl benzene such as monoalkylbenzene, dialkylbenzene, polyalkylbenzene; alkylnaphthalene such as monoalkylnaphthalene, dialkylnaphthalene, polyalkylnaphthalene; dioctyl adipate, di Dibasic acid esters such as -2-ethylhexyl adipate, diisodecyl adipate, ditridecyl adipate, di-2-ethylhexyl sebacate, ditridecyl glutarate Tribasic acid esters such as trimellitic acid; polyol esters such as trimethylolpropane caprylate, trimethylolpropane pelargonate, trimethylolpropane oleate, pentaerythritol 2-ethylhexanoate, pentaerythritol pelargonate; polyethylene glycol, polypropylene glycol Polyglycols such as polyoxyethyleneoxypropylene glycol, polyethylene glycol monoether, polypropylene glycol monoether, polyoxyethyleneoxypropylene glycol monoether, polyethylene glycol diether, polypropylene glycol diether, polyoxyethyleneoxypropylene glycol diether; Monoalkyl diphenyl ether, dialkyl diphenyl Phenyl ethers such as ether, monoalkyl triphenyl ether, dialkyl triphenyl ether, tetraphenyl ether, monoalkyl tetraphenyl ether, dialkyl tetraphenyl ether, and pentaphenyl ether; silicone oils; fluoro ethers such as perfluoro ether, etc. These can be used alone or in combination of two or more.

Examples of fats and oils include beef tallow, lard, soybean oil, rapeseed oil, rice bran oil, coconut oil, palm oil, palm kernel oil, hydrogenated products thereof, or a mixture of two or more of these.

Kinematic viscosity at 100 ° C. of the lubricating base oil is preferably 1 ~ 100mm ² / s, more preferably ² ~ 80mm 2 / s, more preferably 3 ~ 50mm ² / s. When the kinematic viscosity at 100 ° C. is less than 1 mm ² / s, the lubricity is lowered, and the working environment is deteriorated due to generation of mist, such being undesirable. On the other hand, if it exceeds 100 mm ² / s, the amount of the oil that adheres to the workpiece and is carried away increases, which is not preferable.

Kinematic viscosity at 40 ° C. of the lubricating base oil is preferably 1 ~ 500mm ² / s, more preferably 3 ~ 400mm ² / s, more preferably 5 ~ 50mm ² / s. If it is less than 1 mm ² / s, the workability is lowered, and if it exceeds 500 mm ² / s, the washability is lowered.

The content of the lubricating base oil is 40% by mass or more based on the total amount of the lubricating oil composition, preferably 50% by mass or more, more preferably 60% by mass or more, and further preferably 75% by mass or more, and 99.8%. % By mass or less, preferably 98.9% by mass or less, more preferably 98% by mass or less, and still more preferably 95% by mass or less.

The lubricating oil composition of the present invention contains a sulfur-containing compound having a specific structure as the [A] component.
Specifically, the sulfur-containing compound having a specific structure is [A1] a dialkyl polysulfide compound in which the number of sulfur cross-links of 4 or more accounts for 50 mol% or more, and [A2] a sulfurized ester represented by the specific formula. . Each of [A1] and [A2] may use one type of compound or two or more types of compounds. [A1] and [A2] can also be contained at the same time.

The component [A1] is a dialkyl polysulfide compound in which the number of sulfur crosslinks of 4 or more accounts for 50 mol% or more. Dialkyl polysulfide is a compound represented by the following general formula (4).
R- (S) _n -R ' (4)
(In the formula, R and R ′ each represents a linear or branched alkyl group having 1 to 24 carbon atoms, preferably 6 to 18 carbon atoms, and may be the same or different. N represents an integer of 2 to 8. .)

Specific examples of R and R ′ in the general formula (1) include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, Examples thereof include a pentyl group, various hexyl groups, various heptyl groups, various octyl groups, various nonyl groups, various decyl groups, and various dodecyl groups.

Specific examples of the dialkyl polysulfide include di-tert-butyl polysulfide, di-tert-octyl polysulfide, di-tert-nonyl polysulfide, di-sec-octyl polysulfide, di-sec-decyl polysulfide, di-sec-dodecyl polysulfide, Examples include di-sec-hexadecyl polysulfide.

The component [A1] needs to have a content ratio of the dialkyl polysulfide compound in which the number of sulfur crosslinks in the total dialkyl polysulfide compound (n in the above formula (1)) is 4 or more is 50 mol% or more. 55 mol% or more is preferable, and 60 mol% or more is more preferable. When the content ratio of the dialkyl polysulfide compound having 4 or more sulfur bridges is less than 50 mol%, the extreme pressure performance is not sufficient, which is not preferable.
On the other hand, the content ratio of the dialkyl polysulfide compound having 4 or more sulfur bridges is preferably 90 mol% or less, more preferably 85 mol% or less. When the content ratio exceeds 90 mol%, the stability is lowered, which is not preferable.

The content of the component [A1] is not particularly limited, but is preferably 0.1 to 20% by mass, more preferably 0.3 to 15% by mass, and further preferably 0.5 to 10% by mass based on the total amount of the composition. . When the content of the component [A1] is less than 0.1% by mass, a sufficient effect as an extreme pressure agent cannot be obtained, and when it exceeds 20% by mass, the oxidation stability of the lubricating oil composition tends to be lowered. Each of which is not preferable.

[A2] The component is a sulfurized ester represented by the following general formula (1) and / or (2).

R ¹ and R ² in the above general formula (1) or (2) represent hydrogen or a hydrocarbyl group having 1 to 24 carbon atoms, preferably 1 to 3 carbon atoms. Specifically, for example, hydrogen atom; alkyl group such as methyl group, ethyl group, propyl group, isopropyl group; cycloalkyl group such as cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group; phenyl group, cresyl group, etc. Can be mentioned.
Among these, an alkyl group is preferable from the viewpoint of the adsorptivity of the lubricating surface and oxidation stability, and a methyl group and an ethyl group are particularly preferable.

A, b, c and d in the general formula (1) or (2) are each independently an integer of 4 or more, and the sum of a and b is 10 to 16, preferably 10 to 14, and c and The sum of d is 9 to 15, preferably 9 to 13.
If the sum of a and b is less than 10, the solubility is lowered. On the other hand, if it exceeds 16, the storage stability at a low temperature is lowered, which is not preferable. Further, if the sum of c and d is less than 9, the solubility is lowered. On the other hand, if it exceeds 15, the storage stability at a low temperature is lowered.

Examples of the sulfur compounds represented by the general formula (1) and the general formula (2) include unsaturated fatty acids having two unsaturated bonds in the molecule and having 16 to 22 carbon atoms (for example, linoleic acid, eicosadienoic acid, docosadienoic acid) Etc.) by sulfur crosslinking with an ester such as methyl ester or ethyl ester. The raw material unsaturated fatty acid ester is preferably purified, but may be used even if it contains impurities (for example, linolenic acid). The content of impurities in the raw material is preferably 50% by mass or less, more preferably 30% by mass or less, and most preferably 10% by mass or less.

Specific examples of the sulfur compounds represented by the general formulas (1) and (2) include 3-nonanoic methyl ester-5-hexyl-thiolane, 3-nonanoic ethyl ester-5-hexyl-thiolane, 3- Nonanoic propyl ester-5-hexyl-thiolane, 3-dodecanoic methyl ester-5-propyl-thiolane, 3-dodecanoic ethyl ester-5-propyl-thiolane, 3-dodecanoic propyl ester-5-propyl -Thiolane, 3-hexanoic methyl ester-5-nonyl-thiolane, 3-hexanoic ethyl ester-5-nonyl-thiolane, 3-hexanoic propyl ester-5-nonyl-thiolane, 3-nonanoic methyl Ester-5-hexyl-1,2-dithiolane, 3-nonanoic Tylester-5-hexyl-1,2-dithiolane, 3-nonanoic propyl ester-5-hexyl-1,2-dithiolane, 3-dodecanoic methyl ester-5-propyl-1,2-dithiolane, 3-dodeca Neukyl ethyl ester-5-propyl-1,2-dithiolane, 3-dodecanoic propyl ester-5-propyl-1,2-dithiolane, 3-hexanoic methyl ester-5-nonyl-1,2-dithiolane 3-hexanoic ethyl ester-5-nonyl-1,2-dithiolane, 3-hexanoic propyl ester-5-nonyl-1,2-dithiolane, and the like.
Among these, 3-nonanoic methyl ester-5-hexyl-thiolane and 3-nonanoic methyl ester-5-hexyl-1,2-dithiolane are preferable for improving processability.

The sulfurized esters represented by the formulas (1) and (2) may be used alone or in combination. The mixing ratio is arbitrary, but it is preferably used as a mixture having a mass ratio of 1: 2 to 2: 1.

The content of the sulfurized ester represented by the formula (1) and / or (2) is not particularly limited, but the total amount of the composition is based on the total amount of the sulfurized ester represented by the formula (1) and the formula (2). Is preferably 0.1 to 30% by mass, more preferably 0.5 to 25% by mass, and still more preferably 1 to 20% by mass. If it is less than 0.1% by mass, a sufficient effect cannot be obtained, and if it exceeds 30% by mass, the oxidation stability of the lubricating oil composition tends to decrease, which is not preferable.

When the component [A2] is contained, it is preferable to further contain a sulfur compound represented by the following general formula (3) as the component [A3]. By adding the component [A3], workability is further improved.

In the general formula (3), n (the number of sulfur bridges) is a positive number of 1 or more.
[A3] The sulfur compound is usually a mixture of compounds having different numbers of sulfur bridges (n), and n (average number of sulfur bridges) is preferably 2 or more, more preferably 3 to 10, still more preferably 3 to 8.

R ³ and R ⁴ in the general formula (3) represent hydrogen or a hydrocarbyl group having 1 to 24 carbon atoms, preferably 1 to 3 carbon atoms, particularly preferably 1 to 2 carbon atoms. These may be the same or different. Specific examples include a hydrogen atom; an alkyl group such as a methyl group, an ethyl group, a propyl group, and an isopropyl group; and a cycloalkyl group such as a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, and a cyclohexyl group.
Among these, an alkyl group is preferable from the viewpoint of improving processability, and a methyl group and an ethyl group are particularly preferable.

In the above general formula (3), a1, b1, a2 and b2 are each independently an integer of 3 or more, and the sum of a1 and b1 and the sum of a2 and b2 are 8 to 14, preferably 10 to 12, respectively. .
If the sum of a1 and b1 and the sum of a2 and b2 are less than 8, the solubility is lowered. On the other hand, if it exceeds 14, the workability is lowered, which is not preferable.

The sulfur compound represented by the general formula (3) is obtained by sulfur-crosslinking an ester of an unsaturated fatty acid having one unsaturated bond in the molecule and having 16 to 22 carbon atoms (for example, oleic acid). The raw material unsaturated fatty acid ester is preferably purified, but can be used even if it contains impurities. The content of impurities in the raw material is preferably 50% by mass or less, more preferably 30% by mass or less, and most preferably 10% by mass or less.
As the unsaturated fatty acid ester, oleic acid esters such as methyl oleate, ethyl oleate, and propyl oleate are preferable, and among them, a sulfur cross-linked product of methyl oleate is preferable because it exhibits an effective friction reducing effect.

The mass ratio ([A3] / [A2]) of the sulfur compound [A3] represented by the general formula (3) and the sulfur compound [A2] represented by the general formula (1) and / or the general formula (2) is 0. .8 to 20, preferably 0.9 to 19.
If the mass ratio ([A3] / [A2]) of [A3] to [A2] is less than 0.8, the solubility is lowered, and if it exceeds 20, the workability is lowered, which is not preferable.

The total content of the components [A2] and [A3] is 1 to 50% by mass, preferably 2 to 40% by mass, and more preferably 3 to 30% by mass based on the total amount of the composition. If the total content is less than 1% by mass, a sufficient effect cannot be obtained, and if it exceeds 50% by mass, the oxidation stability of the lubricating oil composition tends to be lowered, which is not preferable.

The lubricating oil composition of the present invention contains a metal detergent having a metal ratio of 6 or more as the [B] component.

Examples of the metal detergent include alkali metal sulfonate or alkaline earth metal sulfonate, alkali metal phenate or alkaline earth metal phenate, and alkali metal salicylate or alkaline earth metal salicylate.

As the sulfonate, an alkali metal salt or alkaline earth metal salt of an alkyl aromatic sulfonic acid obtained by sulfonating an alkyl aromatic compound having a molecular weight of 300 to 1500, preferably 400 to 700, such as a sodium salt or a potassium salt. , Magnesium salts, and calcium salts, and calcium salts are particularly preferably used.

Specific examples of the alkyl aromatic sulfonic acid include so-called petroleum sulfonic acid and synthetic sulfonic acid.
As said petroleum sulfonic acid, what sulfonated the alkyl aromatic compound of the lubricating oil fraction of mineral oil, what is called mahoganic acid etc. byproduced at the time of white oil manufacture are generally used. Synthetic sulfonic acids can be obtained by, for example, by-producing from an alkylbenzene production plant that is a raw material for detergents, or by alkylating oligomers of olefins (ethylene, propylene, etc.) having 2 to 12 carbon atoms with benzene. A sulfonated alkylbenzene having a chain or branched alkyl group or a sulfonated alkylnaphthalene such as dinonylnaphthalene is used. The sulfonating agent for sulfonating these alkyl aromatic compounds is not particularly limited, but fuming sulfuric acid or sulfuric anhydride is usually used.

Examples of the phenate include alkylphenols, alkylphenol sulfides, alkali metal salts or alkaline earth metal salts of Mannich reaction products of alkylphenols such as sodium salts, potassium salts, magnesium salts and calcium salts. Specific examples include those represented by the following general formulas (5), (6) and (7).

In the general formulas (5), (6) and (7), R ⁵ to R ¹⁰ each independently represents a linear or branched alkyl group having 4 to 30 carbon atoms, preferably 6 to 18 carbon atoms, M ¹ , M ² and M ³ each represent an alkaline earth metal, preferably calcium or magnesium, and x represents 1 or 2.

Specific examples of the alkyl group represented by R ⁵ to R ¹⁰ include butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, and dodecyl group. , Tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group, nonadecyl group, icosyl group, heicosyl group, docosyl group, tricosyl group, tetracosyl group, pentacosyl group, hexacosyl group, heptacosyl group, octacosyl group, nonacosyl group Group, triacontyl group and the like. These may be linear or branched. These may also be primary alkyl groups, secondary alkyl groups or tertiary alkyl groups.

Examples of the salicylates include alkali metal salts or alkaline earth metal salts of alkyl salicylic acid, such as sodium salts, potassium salts, magnesium salts, and calcium salts. Specific examples include compounds represented by the following general formula (8).

In the general formula (8), R ¹¹ represents a linear or branched alkyl group having 4 to 30 carbon atoms, preferably 6 to 18 carbon atoms, and M ⁴ represents an alkaline earth metal, preferably calcium or magnesium.

Specific examples of the alkyl group represented by R ¹¹ include butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, Examples include pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group, nonadecyl group, icosyl group, heicosyl group, docosyl group, tricosyl group, tetracosyl group, pentacosyl group, hexacosyl group, heptacosyl group, octacosyl group, nonacosyl group, triacontyl group, etc. These may be linear or branched. These may also be primary alkyl groups, secondary alkyl groups or tertiary alkyl groups.

Alkaline earth metal sulfonates, alkaline earth metal phenates, and alkaline earth metal salicylates include the above alkyl aromatic sulfonic acids, alkylphenols, alkylphenol sulfides, Mannich reactants of alkylphenols, alkylsalicylic acid, etc. Or it reacts with alkaline earth metal bases such as calcium alkaline earth metal oxides and hydroxides, or once is converted to an alkali metal salt such as sodium salt or potassium salt and then substituted with alkaline earth metal salt, etc. Neutral (normal salt) alkaline earth metal sulfonate, neutral (normal salt) alkaline earth metal phenate and neutral (normal salt) alkaline earth metal salicylate obtained by: neutral alkaline earth metal sulfonate, neutral Alkaline earth metal phene And a basic alkaline earth metal sulfonate, a basic alkaline earth metal phenate obtained by heating a neutral alkaline earth metal salicylate and an excess of an alkaline earth metal salt or alkaline earth metal base in the presence of water, and A basic alkaline earth metal salicylate; or in the presence of a neutral alkaline earth metal sulfonate, a neutral alkaline earth metal phenate and a neutral alkaline earth metal salicylate; Overbased (superbasic) alkaline earth metal sulfonates, overbased (superbasic) alkaline earth metal phenates and overbased (superbasic) alkaline earth metals obtained by reacting with boric acid Salicylates are also included.

[B] The metal ratio of the metallic detergent of the component needs to be 6 or more, preferably 6.5 or more, and more preferably 7 or more. When the metal ratio is less than 6, workability becomes insufficient, which is not preferable.
The metal ratio here is represented by the valence of metal element × metal element content (mol) / soap group (that is, group such as alkyl salicylic acid group) content (mol). The alkali metal or alkaline earth metal content relative to the alkyl salicylic acid group or alkyl sulfonic acid group content in the alkali metal or alkaline earth metal detergent is shown.

The metal-based detergent is preferably an alkaline earth metal-based detergent from the viewpoint of increasing the metal ratio. Among alkaline earth metal detergents, alkaline earth metal sulfonate is more preferable, and calcium sulfonate is particularly preferable from the viewpoint of processability.

The total base number of the component [B] is not particularly limited, but is preferably 50 to 500 mgKOH / g, more preferably 100 to 450 mgKOH / g. When the total base number is less than 50 mgKOH / g, the lubricity improvement effect tends to be insufficient. On the other hand, those whose total base number exceeds 500 mgKOH / g are very difficult to manufacture and difficult to obtain. It is not preferable.
The total base number referred to here is JIS K 2501 “Petroleum products and lubricants—neutralization number test method”. The total base number [mgKOH / g] by the perchloric acid method measured according to the above.

The content of the component [B] is not particularly limited, but is preferably 0.1 to 10% by mass based on the total amount of the composition. More preferably 0.2% by mass or more, further preferably 0.5% by mass or more, particularly preferably 1% by mass or more, more preferably 8% by mass or less, still more preferably 7% by mass or less, particularly preferably. Is 6% by mass or less, and most preferably 5% by mass or less.
When the content of the component [B] is less than 0.1% by mass, the effect of improving machining efficiency and tool life tends to be insufficient, and when it exceeds 10% by mass, the stability of the metalworking oil composition is lowered. In this case, precipitates tend to be generated, which is not preferable.

In addition, the lubricating oil composition for metal working of the present invention may contain conventionally known additives other than the above-described [A] component and [B] component, if necessary. Examples of such additives include non-chlorine extreme pressure agents other than [A] component; metal detergents other than [B] component; wetting agents such as diethylene glycol monoalkyl ether; acrylic polymer, paraffin wax, microwax, Film forming agents such as slack wax and polyolefin wax; water displacement agents such as fatty acid amine salts; solid lubricants such as graphite, graphite fluoride, molybdenum disulfide, boron nitride, polyethylene powder; amines, alkanolamines, amides, carboxylic acids , Carboxylate, sulfonate, phosphoric acid, phosphate, partial esters of polyhydric alcohol, etc .; metal deactivators such as benzotriazole, thiadiazole; methyl silicone, fluorosilicone, polyacrylate, etc. Antifoaming agent; alkenyl succinimide, benzylamine Ashless dispersants such as polyalkenyl amines polyaminoamide; and the like. The content when these known additives are used in combination is not particularly limited, but the amount is such that the total content of these known additives is 0.1 to 10% by mass based on the total amount of the lubricating oil composition. It is preferable to add. It is preferable that chlorine is not substantially contained, and the chlorine element content is 10 mass ppm or less, particularly 1 mass ppm or less.

The kinematic viscosity of the lubricating oil composition for metal working of the present invention is not particularly limited, but the kinematic viscosity at 40 ° C. is preferably 500 mm ² / s or less from the viewpoint of easy supply to the machined part, and 400 mm ² / s It is more preferably s or less, further preferably 300 mm ² / s or less, particularly preferably 100 mm ² / s or less, and most preferably 50 mm ² / s or less. On the other hand, the kinematic viscosity at 40 ° C. is preferably 1 mm ² / s or more, more preferably 3 mm ² / s or more, and further preferably 5 mm ² / s or more.

Since the lubricating oil composition for metalworking of the present invention is excellent in processing performance such as processing efficiency and tool life, and handling properties, it can be suitably used in a wide range of applications in the metalworking field. The metal processing here is not limited to cutting / grinding, but broadly means general metal processing. Moreover, the lubricating oil composition for metal working of the present invention can be applied not only to metal processing by a normal oil supply method but also to cutting / grinding processing (MQL processing) with a very small amount of oil supply.

Specific examples of metal processing include cutting, grinding, rolling, forging, pressing, drawing, rolling, and the like. Among these, the lubricating oil composition for metal working of the present invention is very useful for applications such as cutting, grinding, and rolling.

Hereinafter, the present invention will be specifically described with reference to examples. However, the present invention is not limited to these examples.

The outline of the test method for evaluating the properties of each prepared lubricating oil composition is as follows.

(Tapping test)
In order to evaluate the performance against tool wear, the tapping energy efficiency E with respect to the standard oil was measured under the following processing conditions for each lubricating oil composition, and the cutting performance was evaluated by this test.
・ Work material: S25C
・ Tool diameter: 8mm
・ Tap pitch: 1.25mm
-Tap rake angle: 10 degrees-Tap biting angle: 1.5 degrees-Tap pilot hole diameter: 7.0 mm
・ Rotation speed: 360rpm
・ Number of processing: 1 hole ・ Standard oil: DIDA (diisodecyl adipate)
-Supply oil amount: 9.0 ml / min

The tapping energy efficiency E is defined by tapping energy efficiency E (%) = (tapping energy when using a comparative standard oil) / (tapping energy when using an oil composition).

(Copper plate corrosion test)
Copper plate corrosivity was evaluated by a method based on JIS K2241. The test temperature is 100 ° C. and the test time is 1 hour.

(Turbidity evaluation test)
80 g of the lubricating oil composition was placed in a 100 ml screw tube, and allowed to stand at 0 ° C. for 1 week, and the presence or absence of turbidity was confirmed and evaluated.

(Example 1 and Comparative Example 1)
Table 1 shows the blending amounts and performances of various lubricating base oils and additives. The addition amount (% by mass) of each additive is based on the total amount of the lubricating oil composition. About each obtained composition, processing performance was evaluated by the tapping test.

(A1) Di-tert-octyl polysulfide (sulfur content: 33.5 mass%, abundance ratio of 4 or more sulfur bridges: 35 mol%), (a2) di-tert-octyl polysulfide (sulfur content: 31 mass%, (A3) di-tert-octyl polysulfide (sulfur content: 20% by mass, abundance ratio of 4 or more sulfur bridges: 35 mol%) is a commercial product. .
(A1-1) Di-tert-octyl polysulfide (sulfur content: 37 mass%, abundance ratio of 4 or more sulfur bridges: 70 mol%), (A1-2) di-tert-octyl polysulfide (sulfur content: 37 mass) %, Abundance ratio of 4 or more sulfur bridges: 70 mol%) and (A1-3) di-sec-dodecyl polysulfide (sulfur content: 26 mass%, abundance ratio of 4 or more sulfur bridges: 55 mol%), Each of (a1), (a2) and (a3) is obtained by fractionating a portion having a high degree of sulfur crosslinking with a silica gel chromatograph.

(Example 2 and Comparative Example 2)
Table 2 shows the blending amounts and performances of various lubricating base oils and additives. The blending amount (mass%) of the base oil and the adding amount (mass%) of each additive are based on the total amount of the lubricating oil composition.
About each obtained composition, processing performance was evaluated by the tapping test and the copper plate corrosion test.

Sulfurized esters A and B are fractions obtained by sulfurizing methyl linoleate or ethyl linoleate to obtain a sulfurized ester, and extracting this sulfurized ester by gel chromatography on silica gel. The content of the compound having 3 or more sulfur crosslinks in the extracted fraction is less than 5% by mass based on the content of sulfur element.

(Example 3 and Comparative Example 3)
Table 3 shows the amounts and performances of various lubricating base oils and additives. The blending amount (mass%) of the base oil and the adding amount (mass%) of each additive are based on the total amount of the lubricating oil composition.
The lubricating oil composition according to Comparative Example 3-4 is the lubricating oil composition of the present invention, but is given as a comparative example for showing the effect of adding the component [A3].
Each of the obtained compositions was subjected to a tapping test and a turbidity evaluation test. Three kinds of sulfurized ester compounds were prepared by the following method.

[A2-3]: Cyclic sulfurized ester represented by formulas (1) and (2) (R ¹ , R ² = CH ₃ , a + b = 12, c + d = 11, mixing ratio is 50:50 by mass ratio)
After 150 g of silica gel is packed in a glass tube, 1.5 g of sulfurized ester (M10 manufactured by DOG) is filled. [A2-3] is obtained from the fraction extracted with 100 ml of a mixed solvent of 5% acetone and 95% toluene after extraction with 150 ml of hexane and 100 ml of toluene. The obtained [A2-3] was identified by C13-NMR, FD-MS and elemental analysis.

[A3-1]: a crosslinked sulfurized ester represented by the formula (3) (active type, R ³ , R ⁴ = CH ₃ , a1 + b1 = 12, a2 + b2 = 12, and a sulfur crosslinking number (n) of 4 or more Is a sulfurized ester occupying 50 mol% or more)
After 150 g of silica gel is packed in a glass tube, 7 g of sulfurized ester (M10 manufactured by DOG) is packed. [A3-1] is obtained from a fraction extracted with 100 ml of acetone after extraction with 150 ml of hexane, 100 ml of toluene, and 100 ml of a mixed solvent of 5% acetone and 95% toluene. The obtained [A3-1] was identified by C13-NMR, FD-MS and elemental analysis.

[A3-2]: a crosslinked sulfurized ester represented by formula (3) (inactive, R ³ , R ⁴ = CH ₃ , a1 + b1 = 12, a2 + b2 = 12, and the number of sulfur bridges (n) is 3 or less Sulfurized esters with more than 50 mol%)
After 150 g of silica gel is packed in a glass tube, 7 g of sulfurized ester (MX16 manufactured by DOG) is packed. After extraction with 150 ml of hexane, 100 ml of toluene, and 100 ml of a mixed solvent of 5% acetone and 95% toluene, [A3-2] is obtained from the fraction extracted with 100 ml of acetone. The obtained [A3-2] was identified by C13-NMR, FD-MS and elemental analysis.

The lubricating oil composition of the present invention is useful because it does not contain a chlorinated extreme pressure agent, has few environmental problems and is easy to handle, and can improve machining efficiency and tool life.

Claims

Lubricating oil base oil, [A1] dialkyl polysulfide in which the number of sulfur crosslinks is 4 or more occupies 50 mol% or more, and [A2] a sulfurized ester represented by general formula (1) and / or formula (2) A lubricating oil composition for metal working containing a selected sulfur-containing compound and a metal detergent [B] having a metal ratio of 6 or more.

(Wherein R 1 and R 2 represent hydrogen or a hydrocarbyl group having 1 to 24 carbon atoms. A, b, c and d are each independently an integer of 4 or more, and the sum of a and b is 10 to 16) The sum of c and d is 9-15.)
[A2] further contains [A3] a sulfurized ester represented by the general formula (3), and the mass ratio of [A3] to [A2] ([A3] / [A2]) is 0.8-20. The lubricating oil composition for metal working according to claim 1, wherein the total content of [A2] and [A3] is 1 to 50% by mass based on the total amount of the lubricating oil composition.

(Wherein n represents a positive number of 1 or more, R 3 and R 4 each independently represent hydrogen or a hydrocarbyl group having 1 to 24 carbon atoms, and a1, b1, a2, and b2 each independently represent 3 or more. (The sum of a1 and b1 and the sum of a2 and b2 are 8 to 14, respectively.)
3. The lubricating oil composition for metal working according to claim 1 or 2, wherein the content of the metal detergent is 0.1 to 10% by mass based on the total amount of the lubricating oil composition.
4. The lubricating oil composition for metal working according to claim 1, wherein the metal detergent is calcium sulfonate.