JP5509547B2 - Industrial lubricating oil composition - Google Patents

Description

  The present invention relates to an industrial lubricating oil composition, and more particularly to an ester-based metal wear reducing agent excellent in wear reducing performance and an industrial lubricating oil composition containing the same.

In recent years, there has been a strong demand for improvement in the performance of lubricating oil in devices and machines used in various industrial fields such as automobiles, home appliances, electronic information devices, and industrial machines. In other words, with the increase in speed, efficiency, and downsizing of equipment, the use conditions of engine oil, transmission oil, metalworking oil, hydraulic fluid, grease, etc. have become more severe, compared to conventional lubricating oil. There is a need for lubricating oils with higher performance.

  Conventionally, mineral oil that is inexpensive and easily available has been mainly used as the lubricating oil. Mineral oil is a mixture of hydrocarbon oils with various chemical structures, and is roughly divided into paraffinic and naphthenic (cycloparaffinic) based on the main hydrocarbon (such as "Tribology Handbook (Yokendo)") . Paraffinic mineral oil and naphthenic mineral oil differ in viscosity characteristics (for example, viscosity index), lubrication characteristics, low-temperature fluidity, heat resistance and compatibility with additives depending on the degree of purification. When using for the base material of each of these, the use which utilized each characteristic is made | formed properly.

  However, as required characteristics such as use under high load conditions and maintenance-free conditions become stricter, it becomes difficult for mineral oil to satisfy the required performance, and various compounds are used as additives. Among them, various compounds are often used as an oil-based agent for the purpose of improving wear reduction performance, which is an important performance as a lubricating oil. As the oily agent, organic acids, higher alcohols, esters and the like are used.

  An object of the present invention is to provide an ester-based metal wear reducing agent having high solubility in a base oil and imparting excellent wear reduction performance, and an industrial lubricating oil composition containing the metal wear reducing agent.

  The inventors of the present invention have obtained the following knowledge as a result of intensive studies on the metal wear reduction effect by the mixture of dibasic acid diester and dibasic acid partial ester in order to achieve the above-mentioned problems.

For at least one base oil selected from the group consisting of mineral oil, animal and vegetable oils and synthetic oils, it is possible to obtain an excellent wear reduction effect by containing the specific dibasic acid diester and dibasic acid partial ester of the present invention. I can do it.
The present invention has been completed based on such knowledge.

  That is, this application provides the following lubricating oil invention.

(Claim 1)
General formula (1) with respect to 100 parts by weight of at least one base oil selected from the group consisting of mineral oil, animal and vegetable oils and synthetic oils

R ¹ OOC-X-COOR ¹ (1)

[In the formula, two R ^{1 s} are the same or different and represent a residue obtained by removing a hydroxyl group from a linear or branched saturated or unsaturated aliphatic monohydric alcohol having 8 to 24 carbon atoms. X represents a residue obtained by removing all carboxyl groups from a saturated or unsaturated dibasic acid having 4 to 10 carbon atoms. ]
1 to 30 parts by weight of a dibasic acid diester represented by the formula (2)

^{R 2 OOC-Y-COOH (} 2)

[Wherein R ² represents a residue obtained by removing a hydroxyl group from a linear or branched saturated or unsaturated aliphatic monohydric alcohol having 8 to 24 carbon atoms. Y represents a residue obtained by removing all carboxyl groups from a saturated or unsaturated dibasic acid having 4 to 10 carbon atoms. ]
An industrial lubricating oil composition comprising 0.02 to 5 parts by weight of a dibasic acid partial ester represented by the formula:

(Section 2)
Item 2. The composition according to Item 1, wherein the industrial lubricating oil composition is a metalworking lubricating oil composition or a mechanical lubricating oil composition.

(Section 3)
Item 2. A method for reducing metal wear, which uses the industrial lubricating oil composition according to Item 1.

(Section 4)

General formula (1)

R ¹ OOC-X-COOR ¹ (1)

[In the formula, two R ^{1 s} are the same or different and represent a residue obtained by removing a hydroxyl group from a linear or branched saturated or unsaturated aliphatic monohydric alcohol having 8 to 24 carbon atoms. X represents a residue obtained by removing all carboxyl groups from a saturated or unsaturated dibasic acid having 4 to 10 carbon atoms. ]
Dibasic acid diester represented by the general formula (2)

^{R 2 OOC-Y-COOH (} 2)

[Wherein R ² represents a residue obtained by removing a hydroxyl group from a linear or branched saturated or unsaturated aliphatic monohydric alcohol having 8 to 24 carbon atoms. Y represents a residue obtained by removing all carboxyl groups from a saturated or unsaturated dibasic acid having 4 to 10 carbon atoms. ]
The metal wear reducing agent which contains the dibasic acid partial ester represented by these in the ratio of 1: 0.001-1: 0.5.

(Section 5)
General formula (1) with respect to 100 parts by weight of at least one base oil selected from the group consisting of mineral oil, animal and vegetable oils and synthetic oils

R ¹ OOC-X-COOR ¹ (1)

[In the formula, two R ^{1 s} are the same or different and represent a residue obtained by removing a hydroxyl group from a linear or branched saturated or unsaturated aliphatic monohydric alcohol having 8 to 24 carbon atoms. X represents a residue obtained by removing all carboxyl groups from a saturated or unsaturated dibasic acid having 4 to 10 carbon atoms. ]
1 to 30 parts by weight of a dibasic acid diester represented by the formula (2)

^{R 2 OOC-Y-COOH (} 2)

[Wherein R ² represents a residue obtained by removing a hydroxyl group from a linear or branched saturated or unsaturated aliphatic monohydric alcohol having 8 to 24 carbon atoms. Y represents a residue obtained by removing all carboxyl groups from a saturated or unsaturated dibasic acid having 4 to 10 carbon atoms. ]
A method for improving the metal wear reduction performance of a base oil, comprising 0.02 to 5 parts by weight of a dibasic acid partial ester represented by the formula:

  According to the present invention, for at least one base oil selected from the group consisting of mineral oil, animal and vegetable oils and synthetic oils, a lubricating oil composition containing the specific dibasic acid diester and dibasic acid partial ester of the present invention is Excellent metal wear reduction performance.

[Ester metal wear reducer]
The metal wear reduction performance of the base oil is improved by blending the mixture of the specific dibasic acid diester and the dibasic acid partial ester according to the present invention with the base oil. In other words, the mixture of the specific dibasic acid diester and the dibasic acid partial ester according to the present invention functions as a metal wear reducing agent.

  The blending ratio of the dibasic acid diester and the dibasic acid partial ester in the ester-based metal wear reducing agent is usually 1: 0.001 to 1: 0.5 (weight ratio).

The dibasic acid diester of the present invention is represented by the following general formula (1).

R ¹ OOC-X-COOR ¹ (1)

  In the general formula (1), X is a residue obtained by removing all carboxyl groups from a saturated or unsaturated dibasic acid having 4 to 10 carbon atoms. Examples of the dibasic acid include succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, fumaric acid, maleic acid, citraconic acid, mesaconic acid, suberic acid, azelaic acid, sebacic acid, and the like. Acid, adipic acid, azelaic acid and sebacic acid are preferred. You may use the said dibasic acid 1 type or in mixture of 2 or more types.

In the formula of the general formula (1), two R ^{1 s} are the same or different and are obtained by removing a hydroxyl group from a linear or branched saturated or unsaturated aliphatic monohydric alcohol having 8 to 24 carbon atoms. Represents a residue. Examples of the saturated aliphatic monohydric alcohol include n-octanol, n-decanol, n-undecanol, n-dodecanol, n-tridecanol, n-tetradecanol, n-pentadecanol, n-hexadecanol, n-octa A decanol etc. are mentioned. Specific examples of the branched saturated aliphatic monohydric alcohol include 2-ethylhexanol, isononanol, 3,5,5-trimethylhexanol, isodecanol, isoundecanol, isododecanol, isotridecanol, isotetradecane. Examples include decanol, isopentadecanol, isohexadecanol, 2-hexyldecanol, isooctadecanol, 2-octyldodecanol, and 2-decyltetradecanol. Specific examples of the linear unsaturated aliphatic monohydric alcohol include oleyl alcohol.

The aliphatic monohydric alcohol can be used for the esterification reaction alone or in combination of two or more. Among the above aliphatic monohydric alcohols, 2-hexyldecanol, isooctadecanol, 2-octyldodecanol, 2-decyltetradecanol, and oleyl alcohol are preferred because of excellent balance between volatility and low temperature fluidity. . Furthermore, oleyl alcohol is preferred because it exhibits particularly excellent lubricity.

The dibasic acid partial ester of the present invention is represented by the following general formula (2).

^{R 2 OOC-Y-COOH (} 2)

In the formula of the general formula (2), Y is a residue obtained by removing all carboxyl groups from a saturated or unsaturated dibasic acid having 4 to 10 carbon atoms. Examples of the dibasic acid are the same as the specific examples of the dibasic acid according to the general formula (1).

In the formula of the general formula (2), R ² represents a residue obtained by removing a hydroxyl group from a linear or branched saturated or unsaturated aliphatic monohydric alcohol having 8 to 24 carbon atoms. As this aliphatic monohydric alcohol, the thing similar to the specific example of the aliphatic monohydric alcohol which concerns on the said General formula (1) is illustrated.

  X in the general formula (1) and Y in the general formula (2) may be the same or different.

Two R ^{1 in the} general formula (1) and R ^{2 in the} general formula (2) may be the same or different.

[Production Method of Ester-Based Metal Abrasion Reducing Agent]
The method for producing the ester metal wear reducing agent of the present invention is not particularly limited as long as it is obtained by the mixing ratio of the dibasic acid diester and the dibasic acid partial ester defined in the present invention.
The following method is mentioned as a specific example of a manufacturing method.
(1) A method of simultaneously obtaining a mixture of a dibasic acid diester and a dibasic acid partial ester by an esterification reaction between a dibasic acid or an ester-forming derivative and an aliphatic monohydric alcohol.
(2) A method of producing a dibasic acid diester and a dibasic acid partial ester separately and mixing them in a later step.

When the ester-based lubricating oil additive of the present invention is directly obtained as a mixture of a dibasic acid diester and a dibasic acid partial ester, the esterification reaction of the dibasic acid and the aliphatic monohydric alcohol is carried out, and the ester is completely esterified. A method of leaving the partial ester without completing the crystallization reaction is simple.
In the esterification reaction, an ester-forming derivative may be used in place of the dibasic acid. Examples of the ester-forming derivatives include active esters such as anhydrides, chlorides, esters of lower alcohols having 1 to 4 carbon atoms, and aryl esters of the above dibasic acids.

As a method for the esterification reaction, for example, 2.0 mol of the above aliphatic monohydric alcohol is charged all at once with respect to 1 mol of the dibasic acid, and the diester and the partial ester are brought to a predetermined ratio while removing the generated water. The method of performing esterification reaction until it becomes is illustrated.
The amount of the aliphatic monohydric alcohol charged is not particularly limited as long as a mixture of the dibasic acid diester and the dibasic acid partial ester is obtained within the scope of the present invention. Furthermore, an excessive amount can be charged.

  More specifically, the esterification reaction temperature is usually 120 to 250 ° C, preferably 130 to 230 ° C. Moreover, as reaction time, it is 1 to 10 hours normally, Preferably, 2 to 8 hours are illustrated. The reaction may be performed without a catalyst or in the presence of an esterification catalyst described later.

  Examples of esterification catalysts include Lewis acids, alkali metals, sulfonic acids, and the like. Specific examples of Lewis acids include aluminum derivatives, tin derivatives, and titanium derivatives. Examples of alkali metals include sodium alkoxide and potassium. Examples include alkoxides, and examples of the sulfonic acids include p-toluenesulfonic acid, methanesulfonic acid, and sulfuric acid. Of these, titanium derivatives and sulfonic acids are preferable. The amount used is, for example, about 0.05 to 1.0% by weight with respect to the total weight of the acid component and alcohol component as raw materials.

  In the esterification reaction, the generated water may be distilled off azeotropically outside the system using a water entraining agent such as benzene, toluene, xylene, cyclohexane or the like, if necessary.

  After completion of the esterification reaction, excess raw material is distilled off under reduced pressure or normal pressure. Subsequently, the present ester can be purified using a conventional purification method, for example, washing with water, distillation under reduced pressure, purification of an adsorbent such as activated carbon.

[Industrial lubricating oil composition]
The industrial lubricating oil composition of the present invention is a lubricating oil composition comprising the above-described ester-based metal wear reducing agent and a base oil.

  The content of each component of the industrial lubricating oil composition of the present invention is usually 1 to 30 parts by weight, preferably 5 to 30 parts by weight of a dibasic acid diester, and 100 parts by weight of a dibasic acid partial ester, based on 100 parts by weight of the base oil In an amount of 0.02 to 5 parts by weight, preferably 0.1 to 5 parts by weight.

[Base oil]
The base oil that can be used in the industrial lubricating oil composition of the present invention is at least one selected from the group consisting of mineral oil, animal and vegetable oils, and synthetic oils, and these base oils may be used alone or in combination of two or more. Can be used.
As the mineral oil, a mineral oil generally used as a base oil in the field of lubricating oil can be used. As mineral oil, for example, a lubricating oil fraction obtained by further distilling atmospheric residue obtained by atmospheric distillation of crude oil is subjected to solvent removal, solvent extraction, hydrocracking, solvent dewaxing, hydrogenation. Examples include base oils manufactured by isomerizing waxes (gas-to-liquid waxes) that have been refined by performing one or more treatments such as refining, or mineral oil-based waxes or Fischer-Tropsch processes. . As the mineral oil used in the present invention, one having a kinematic viscosity at 100 ° C. in the range of 1.5 to 40 mm ² / s is preferable.
Examples of animal and vegetable oils include beef tallow, lard, palm oil, coconut oil, rapeseed oil, castor oil, and the like.
Synthetic oils include synthetic hydrocarbon oils such as poly-α-olefin, polybutene, alkylbenzene, and alkylnaphthalene, and isomerized oils of synthetic hydrocarbons obtained by the Fischer-Tropsch method, as well as polyethers.

Examples of the poly-α-olefin include α-olefins having 2 to 16 carbon atoms (for example, ethylene, propylene, 1-butene, 1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene). Etc.), and a compound having a kinematic viscosity at 100 ° C. of 1.5 to 40 mm ² / s and a viscosity index of 100 or more is preferable, and a kinematic viscosity at 100 ° C. of 3 to 30 mm ² / It is more preferable that the viscosity index is 120 or more.

Examples of polybutene include a polymer of isobutylene and a copolymer of isobutylene and normal butylene, and generally a wide range of kinematic viscosity at 100 ° C. of ² to 6000 mm ² / s is preferable.

  Examples of the alkyl benzene include monoalkyl benzene, dialkyl benzene, trialkyl benzene, and tetraalkyl benzene having a molecular weight of 200 to 450, which are substituted with a linear or branched alkyl group having 1 to 40 carbon atoms.

  Examples of the alkylnaphthalene include monoalkylnaphthalene and dialkylnaphthalene substituted with a linear or branched alkyl group having 1 to 30 carbon atoms.

  Examples of the polyether include polyethylene glycol, polypropylene glycol, oxyethylene-oxypropylene copolymer, polyester ether, polyphenyl ether and the like, and generally include a wide range of those having a kinematic viscosity at 100 ° C. of 2 to 4000 mm 2 / s. .

Among the above base oils, it is preferable to use a mineral oil as the base oil from the viewpoint of easy availability and function as a lubricating oil.

  In order to improve the performance of the lubricating oil of the present invention, known antioxidants, metal detergents, ashless dispersants, oiliness agents, antiwear agents, extreme pressure agents, metal deactivators, rust inhibitors, One or more additives such as a viscosity index improver, a pour point depressant, and an antifoaming agent can be appropriately blended. Although these compounding quantities are not specifically limited as long as there exists a predetermined effect, The specific example is shown below.

  Antioxidants include 2,6-di-tert-butyl-p-cresol, 2-tert-butyl-4-hydroxyanisole, 2,5-di-tert-butylhydroquinone, 4-hydroxymethyl-2,6 -Phenols such as di-tert-butylphenol, 4,4'-methylenebis-2,6-di-tert-butylphenol, 2,2'-methylenebis-4-methyl-6-tert-butylphenol, N-phenyl-α Examples thereof include amine compounds such as naphthylamine and p, p′-dioctyldiphenylamine, and sulfur compounds such as p, p′-dinonyldiphenylamine, mixed dialkyldiphenylamine and phenothiazine. These antioxidants can be used alone or in combination. When used, these antioxidants are usually added in an amount of 0.01 to 5 parts by weight, preferably 0.05 to 3 parts by weight, based on 100 parts by weight of the lubricating base oil.

  Metal detergents include Ca-petroleum sulfonate, overbased Ca-petroleum sulfonate, Ca-alkyl benzene sulfonate, overbased Ca-alkyl benzene sulfonate, Ba-alkyl benzene sulfonate, over-based Ba-alkyl benzene sulfonate. Phonate, Mg-alkylbenzenesulfonate, overbased Mg-alkylbenzenesulfonate, Na-alkylbenzenesulfonate, overbased Na-alkylbenzenesulfonate, Ca-alkylnaphthalenesulfonate, overbased Ca- Metal sulfonates such as alkyl naphthalene sulfonates, Ca-phenates, overbased Ca-phenates, Ba-phenates, overbased Ba-phenates and other metal phenates, Ca-salicylate, overbased C Metal salicylates such as salicylates, Ca-phosphonates, overbased Ca-phosphonates, Ba-phosphonates, overbased Ba-phosphonates and other metal phosphonates, overbased Ca-carboxylates Etc. are exemplified. These metal detergents can be used alone or in combination. When these metal detergents are used, it is usually desirable to add 1 to 10 parts by weight, preferably 2 to 7 parts by weight, per 100 parts by weight of the lubricating base oil.

  Examples of the ashless dispersant include polyalkenyl succinimide, polyalkenyl succinamide, polyalkenyl benzylamine, polyalkenyl succinate and the like. These ashless dispersants can be used alone or in combination. When used, these ashless dispersants are usually added in an amount of 1 to 10 parts by weight, preferably 2 to 7 parts by weight, based on 100 parts by weight of the lubricating base oil.

  Examples of oily agents include aliphatic saturated and unsaturated monocarboxylic acids such as stearic acid and oleic acid, polymerized fatty acids such as dimer acid and hydrogenated dimer acid, hydroxy fatty acids such as ricinoleic acid and 12-hydroxystearic acid, lauryl alcohol, Aliphatic saturated and unsaturated monoalcohols such as oleyl alcohol, aliphatic saturated and unsaturated monoamines such as stearylamine and oleylamine, aliphatic saturated and unsaturated monocarboxylic amides such as lauric acid amide, oleic acid amide, batyl alcohol, Glycerol ethers such as chimyl alcohol and ceralkyl alcohol, alkyl or alkenyl polyglyceryl ethers such as lauryl polyglyceryl ether and oleyl polyglyceryl ether, di (2-ethylhexyl) monoethanolamine , Poly (alkylene oxide) alkyl or alkenyl amines such as diisotridecyl monoethanolamine adduct and the like. These oily agents may be used alone or in combination. When these oil-based agents are used, they are usually added in an amount of 0.01 to 5 parts by weight, preferably 0.1 to 3 parts by weight, based on 100 parts by weight of the lubricating base oil.

  Antiwear / extreme pressure agents include tricresyl phosphate, cresyl diphenyl phosphate, alkylphenyl phosphates, phosphate esters such as tributyl phosphate, dibutyl phosphate, tributyl phosphate, dibutyl phosphate, triisopropyl phosphate, etc. Phosphorous esters of these and phosphorus salts such as amine salts thereof, sulfurized fatty acids such as sulfurized fats and oils, sulfurized oleic acid, sulfurous systems such as dibenzyl disulfide, sulfurized olefin and dialkyl disulfide, Zn-dialkyldithiophosphate, Zn- Examples thereof include organometallic compounds such as dialkyldithiophosphate, Mo-dialkyldithiophosphate, and Mo-dialkyldithiocarbamate. These antiwear agents can be used alone or in combination. These antiwear / extreme pressure agents are usually added in an amount of 0.01 to 10 parts by weight, preferably 0.1 to 5 parts by weight, based on 100 parts by weight of the lubricating base oil.

  Examples of the metal deactivator include benzotriazole-based, thiadiazole-based, and gallic acid ester-based compounds. These metal deactivators can be used alone or in combination. When used, these metal deactivators are usually added in an amount of 0.01 to 0.4 parts by weight, preferably 0.01 to 0.2 parts by weight, based on 100 parts by weight of the lubricating base oil. .

  Antirust agents include alkyl or alkenyl succinic acid derivatives such as dodecenyl succinic acid half ester, octadecenyl succinic anhydride, dodecenyl succinic acid amide, sorbitan monooleate, glycerin monooleate, pentaerythritol monooleate Partial alcohol ester, Ca-petroleum sulfonate, Ca-alkyl benzene sulfonate, Ba-alkyl benzene sulfonate, Mg-alkyl benzene sulfonate, Na-alkyl benzene sulfonate, Zn-alkyl benzene sulfonate, Ca-alkyl naphthalene sulphate Examples thereof include metal sulfonates such as phonates, amines such as rosinamine and N-oleylsarcosine, dialkyl phosphiteamine salts, and the like. These rust inhibitors can be used alone or in combination. When used, these rust inhibitors are usually added in an amount of 0.01 to 5 parts by weight, preferably 0.05 to 2 parts by weight, based on 100 parts by weight of the lubricating base oil.

  Examples of the viscosity index improver include olefin copolymers such as polyalkyl methacrylate, polyalkyl styrene, polybutene, ethylene-propylene copolymer, styrene-diene copolymer, and styrene-maleic anhydride ester copolymer. . These viscosity index improvers can be used alone or in combination. When used, these viscosity index improvers are usually added in an amount of 0.1 to 15 parts by weight, preferably 0.5 to 7 parts by weight, based on 100 parts by weight of the lubricating base oil.

  Examples of the pour point depressant include a condensate of chlorinated paraffin and alkylnaphthalene, a condensate of chlorinated paraffin and phenol, polyalkyl methacrylate, polyalkylstyrene, polybutene and the like as the viscosity index improvers described above. These pour point depressants can be used alone or in combination. When using these pour point improvers, it is usually desirable to add 0.01 to 5 parts by weight, preferably 0.1 to 3 parts by weight, per 100 parts by weight of the lubricating base oil.

  As the antifoaming agent, liquid silicone is suitable. When the antifoaming agent is used, the amount added is usually 0.0005 to 0.01 parts by weight with respect to 100 parts by weight of the lubricating base oil.

An industrial lubricating oil composition containing at least one base oil selected from the group consisting of mineral oils, animal and vegetable oils and synthetic oils of the present invention, a specific dibasic acid diester and a dibasic acid partial ester is excellent in metal wear reduction performance. Therefore, it is useful as a lubricating oil composition for metal working or a mechanical lubricating oil composition. Specific applications of lubricating oil compositions for metal working include cutting oils, rolling oils, drawing / drawing oils, cleaning oils, plastic working oils, stamping oils, heat treatment oils, heat medium oils, etc. Specific applications of the oil composition include turbine oil, hydraulic fluid, bearing oil, gear oil, compressor oil, traction oil, and the like.

  EXAMPLES The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. In Examples and Comparative Examples, various properties of esters, physical properties and chemical properties of lubricating oil were measured by the following methods.

(A) Total acid value It measured based on JISK2501.

(B) Lubricity test In accordance with JPI-5S-32-90, using a high-speed four-ball wear tester (manufactured by SHINKO MACHINERY), the test was performed under conditions of a rotation speed of 1200 rpm, a load of 20 kg, and a time of 60 minutes. The scar diameter was measured. It was judged that the smaller the wear scar formed, the better the lubricity.
The composition of the lubricating oil used in the test was as follows.
This ester mixture or partial ester / Cosmo neutral 100
= 10/90 (parts by weight)
Cosmo Neutral 100: Cosmo Oil Lubricants, 40 ° C kinematic viscosity 21.3 mm ² / s

[Production Example 1]
In a 1 liter four-necked flask equipped with a stirrer, a thermometer and a water fraction receiver with a cooling tube, 146 g (1.0 mol) (1.0 mol) of adipic acid, oleyl alcohol (manufactured by Shin Nippon Rika) ANGEL COAL 90 ") 564g (2.1mol) and toluene are charged, and the temperature is gradually raised to 210 ° C under a nitrogen atmosphere. The esterification reaction was carried out while removing with a water fraction receiver. Toluene and excess alcohol were removed by distillation and filtration was performed to obtain 600 g of an ester mixture.
The total acid value of the obtained ester mixture (1) was 7.0 mgKOH / g.

[Production Example 2]
Instead of the oleyl alcohol of Production Example 1, 2-octyldodecanol (Nippol Chemical's “NJECOAL 200A” 636 g (2.1 mol)) was used in the same manner as in Production Example 1, except that 680 g of the ester mixture was obtained. Obtained.
The total acid value of the obtained ester mixture (2) was 12.8 mgKOH / g.

[Production Example 3]
780 g of ester mixture was prepared in the same manner as in Production Example 1 except that 2-decyltetradecanol (“NJECOAL 240A” 764 g (2.1 mol) manufactured by Shin Nippon Chemical Co., Ltd.) was used instead of oleyl alcohol in Production Example 1. Got.
The total acid value of the obtained ester mixture (3) was 6.5 mgKOH / g.

[Production Example 4]
560 g of an ester mixture was obtained in the same manner as in Production Example 1, except that 519 g (2.1 mol) of 2-hexyldecanol (“NJECOLL 160B” manufactured by Shin Nippon Chemical Co., Ltd.) was used instead of the oleyl alcohol of Production Example 1. .
The total acid value of the obtained ester mixture (4) was 7.0 mgKOH / g.

Examples 1-4
The ester mixtures (1) to (4) obtained by the methods of Production Examples 1 to 4 and the base oil Cosmo Neutral 100 were mixed at 10/90 (parts by weight) to obtain a sample oil, which was used for the lubricity test. The weight composition ratio of partial ester / diester / base oil in the sample oil determined from the AV and molecular weight of the ester mixture is shown in Table 1.

Claims (5)

General formula (1) with respect to 100 parts by weight of at least one base oil selected from the group consisting of mineral oil, animal and vegetable oils and synthetic oils

R ¹ OOC-X-COOR ¹ (1)

[In the formula, two R ^{1 s} represent residues obtained by removing a hydroxyl group from oleyl alcohol . X represents a residue obtained by removing all carboxyl groups from a saturated or unsaturated dibasic acid having 4 to 10 carbon atoms. ]
1 to 30 parts by weight of a dibasic acid diester represented by the formula (2)

^{R 2 OOC-Y-COOH (} 2)

[Wherein R ² represents a residue obtained by removing a hydroxyl group from oleyl alcohol . Y represents a residue obtained by removing all carboxyl groups from a saturated or unsaturated dibasic acid having 4 to 10 carbon atoms. ]
An industrial lubricating oil composition comprising 0.02 to 5 parts by weight of a dibasic acid partial ester represented by the formula:   The composition according to claim 1, wherein the industrial lubricating oil composition is a metal working lubricating oil composition or a mechanical lubricating oil composition.   A method for reducing metal wear using the industrial lubricating oil composition according to claim 1. General formula (1)

R ¹ OOC-X-COOR ¹ (1)

[In the formula, two R ^{1 s} represent residues obtained by removing a hydroxyl group from oleyl alcohol . X represents a residue obtained by removing all carboxyl groups from a saturated or unsaturated dibasic acid having 4 to 10 carbon atoms. ]
Dibasic acid diester represented by the general formula (2)

^{R 2 OOC-Y-COOH (} 2)

[Wherein R ² represents a residue obtained by removing a hydroxyl group from oleyl alcohol . Y represents a residue obtained by removing all carboxyl groups from a saturated or unsaturated dibasic acid having 4 to 10 carbon atoms. ]
The metal wear reducing agent which contains the dibasic acid partial ester represented by these in the ratio of 1: 0.001-1: 0.5. General formula (1) with respect to 100 parts by weight of at least one base oil selected from the group consisting of mineral oil, animal and vegetable oils and synthetic oils

R ¹ OOC-X-COOR ¹ (1)

[In the formula, two R ^{1 s} represent residues obtained by removing a hydroxyl group from oleyl alcohol . X represents a residue obtained by removing all carboxyl groups from a saturated or unsaturated dibasic acid having 4 to 10 carbon atoms. ]
1 to 30 parts by weight of a dibasic acid diester represented by the formula (2)

^{R 2 OOC-Y-COOH (} 2)

[Wherein R ² represents a residue obtained by removing a hydroxyl group from oleyl alcohol . Y represents a residue obtained by removing all carboxyl groups from a saturated or unsaturated dibasic acid having 4 to 10 carbon atoms. ]
A method for improving the metal wear reduction performance of a base oil, comprising 0.02 to 5 parts by weight of a dibasic acid partial ester represented by the formula: