JP2021066809A - Lubricating oil composition - Google Patents

Abstract

To provide a lubricating oil composition having high electrical insulation (high volume resistivity) and excellent component protection performance, such as wear resistance, seizure resistance, gear fatigue resistance, and bearing fatigue resistance, even if the kinematic viscosity of the lubricating oil composition at 40°C is lowered.SOLUTION: In a lubricating oil composition comprising the following components (A) to (F): (A) a base oil for lubricating oil; (B) a metal cleaning agent; (C) a phosphorus-based extreme pressure agent; (D) a sulfur-based extreme pressure agent; (E) an ashless dispersant; and (F) a viscosity index improver having a weight average molecular weight (Mw) of 10,000 to 100,000, the phosphorus-based extreme pressure agent (C) contains (C1) one or more selected from phosphite esters and phosphonate esters and (C2) acidic phosphate esters having an alkyl group of 11 to 30 carbons, the ashless dispersant (E) contains a specific succinic acid imide, and the content of boron in the lubricating oil composition is 25 to 150 mass ppm.SELECTED DRAWING: None

Description

The present invention is a lubricating oil composition, particularly a lubricating oil composition applicable for automobiles, more preferably a lubricating oil composition used in a hybrid vehicle, an electric vehicle or a fuel cell vehicle, and more preferably of these automobiles. The present invention relates to a lubricating oil composition that can be used as a gear oil or a transmission oil.

Lubricating oil compositions are used in a wide variety of applications such as automobiles and machinery. In recent years, it has been required to reduce the viscosity of the lubricating oil composition for automobiles from the viewpoint of fuel efficiency. However, lowering the viscosity of the lubricating oil composition affects the oil film forming ability. The low viscosity is originally intended to realize fuel saving, but even if the viscosity of the conventional lubricating oil composition is lowered as it is, the oil film forming ability is inferior, so that the friction is rather high. Depending on the situation, it may not be possible to achieve fuel efficiency. Further, when the oil film forming ability is lowered due to the low viscosity, direct contact between the metals occurs, and as a result, sufficient lubrication is not performed, and as a result, wear becomes severe, so that the function as a lubricating oil composition can be obtained. It will not be fully fulfilled.

In recent years, automotive lubricating oil compositions have been used in hybrid vehicles, electric vehicles, and fuel cell vehicles. In that case, not only fuel efficiency is reduced by lowering the viscosity, but also wear resistance, seizure resistance, and advanced characteristics. Gear fatigue characteristics, high bearing fatigue characteristics, low friction characteristics, and high electrical insulation (high volume resistance) are required. Furthermore, compatibility of lubricating oil with automobile members is also required. It is extremely difficult to ensure these properties by simply reducing the viscosity of the conventionally used lubricating oil composition.

Patent Document 1 contains a lubricating oil base oil, a copolymer of an ester monomer having a polymerizable unsaturated bond and an α-olefin, and a performance additive containing phosphorus, sulfur and boron as constituent elements. The lubricating oil composition to be used is described, and it is described that it is excellent in abrasion resistance, seizure resistance, and fuel saving property. Patent Document 2 describes a lubricating base oil having a kinematic viscosity at 100 ° C. of 1.0 mm ² / s or more and 3.0 mm ² / s or less, a performance additive containing phosphorus, sulfur and boron as constituent elements, and a poly. It contains at least one succinic acid imide compound selected from the group consisting of alkyl succinate imides and polyalkenyl succinate imides, and a copolymer of an ester monomer having a polymerizable unsaturated bond and α-olefin. A lubricating oil composition is described, and it is described that the lubricating oil composition is excellent in defoaming property, abrasion resistance, seizure resistance, and fuel saving property. Patent Document 3 uses a wax isomerized base oil and / or a polyalphaolefin having specific properties as a base oil, and further combines a specific friction modifier, a sulfur-based extreme pressure agent, and a non-boric acid modification dispersant. Therefore, it is described that a lubricating oil composition satisfying high fuel saving by reducing the viscosity, durability of unit members, and economy is provided. However, none of these documents mention high electrical insulation (high volume resistivity) at all.

Patent Document 4 discloses a lubricating oil composition having a high viscosity index by using a viscosity index improver having a specific structure in a mineral oil having a kinematic viscosity at 100 ° C. of ^{2 to 2.5 mm 2 / s.} ing. However, the lubricating oil composition described in Patent Document 4 has a kinematic viscosity of 4 mm ² / s or more at 100 ° C., and the additive formulation is detailed because only general additives are described. There is no description.
On the other hand, the inventors of the present applicants have found that when the kinematic viscosity of the lubricating oil composition at 40 ° C. is 10 mm ² / s or less, good results are not always obtained in terms of wear.

Japanese Unexamined Patent Publication No. 2016-190918 Japanese Unexamined Patent Publication No. 2016-19919 JP-A-2017-138393 Japanese Unexamined Patent Publication No. 2017-155193

In view of the above circumstances, the present invention has wear resistance, seizure resistance, and gear fatigue resistance even when the kinematic viscosity of the lubricating oil composition at 40 ° C. is ^{reduced to more than 10 mm 2} / s and 20 mm ^{2 / s or less.} It is an object of the present invention to provide a lubricating oil composition having excellent component protection performance such as bearing fatigue resistance and high electrical insulation (high volume resistance).

As a result of diligent studies to solve the above problems, the present inventors have conducted a diligent study and found that a lubricating oil essentially containing a metal detergent, a specific phosphorus-based extreme pressure agent, a sulfur-based extreme pressure agent, a viscosity index improver, and an ashless dispersant. A composition which contains a non-borrated succinate imide having the following specific structure and a boring succinate imide having a specific molecular weight as an ashless dispersant, and a viscosity index improver having a specific weight average molecular weight is used. By limiting the amount of boron contained in the lubricating oil composition, it has excellent component protection performance such as wear resistance, gear fatigue resistance, and bearing fatigue resistance even if the viscosity is lowered, and has a high volume resistance. Moreover, it has been found that a lubricating oil composition having excellent seizure resistance can be provided.

（式中、Ｒは、互いに独立に、炭素数６〜１４のα−オレフィンから導かれる繰り返し単位を有する、炭素数２０〜１０００のポリα−オレフィン残基であり、ａは１〜１０の整数である）、及び
（Ｅ２）重量平均分子量（Ｍｗ）１５００〜４５００を有する、ポリα−オレフィンコハク酸イミドのホウ素化物
を含み、
該潤滑油組成物の４０℃における動粘度が１０ｍｍ^２／ｓ超〜２０ｍｍ^２／ｓの範囲にあり、かつ該潤滑油組成物中のホウ素含有量が２５〜１５０質量ｐｐｍであることを特徴とする、
前記潤滑油組成物に関する。 That is, the present invention
In the lubricating oil composition containing the following components (A) to (F),
(A) Lubricating oil base oil,
(B) Metal cleaner,
(C) Phosphorus-based extreme pressure agent,
(D) Sulfur-based extreme pressure agent,
(E) Ash-free dispersant,
And (F) a viscosity index improver having a weight average molecular weight (Mw) of 10,000 to 100,000,
The (C) phosphorus-based extreme pressure agent contains one or more selected from (C1) phosphite ester and phosphonic acid ester, and (C2) acidic phosphoric acid ester having an alkyl group having 11 to 30 carbon atoms. E) The ashless dispersant is (E1) poly α-olefin-containing (poly) ethyleneamine succinate imide represented by the following formula.

(In the formula, R is a polyα-olefin residue having 20 to 1000 carbon atoms having a repeating unit derived from an α-olefin having 6 to 14 carbon atoms independently of each other, and a is an integer of 1 to 10 carbon atoms. ), And (E2) containing a boronized product of a poly-α-olefin succinimide having a weight average molecular weight (Mw) of 1500-4500.
And wherein the kinematic viscosity at 40 ° C. of the lubricating oil composition is in the range of 10 mm ² / s Ultra to 20 mm ² / s, and the boron content of the lubricating oil composition is 25 to 150 ppm by weight To do,
The present invention relates to the lubricating oil composition.

A preferred embodiment of the present invention has at least one feature selected from the following (1) to (16).
(1) The (A) lubricating oil base oil has a kinematic viscosity of 1 to 4.5 mm ² / s at 100 ° C. (2) The (B) metal detergent is calcium salicylate, calcium sulfonate, magnesium salicylate and magnesium sulfonate. (3) The (B) metal cleaning agent has a total base value of 50 to 600 mgKOH / g (4) In the component (C1), the phosphite ester has 4 to 30 carbon atoms. The phosphonic acid ester has an alkyl group having 4 to 30 carbon atoms.
(5) The (C2) acidic phosphoric acid ester has an alkyl group having 11 to 20 carbon atoms. (6) The (D) sulfur-based extreme pressure agent is at least selected from thiasiazol, olefin sulfide, fat and oil sulfide, and sulfide ester. Type 1 (7) The (D) sulfur-based extreme pressure agent has an active sulfur amount of 0.5 to 15% by mass (8) further contains an organic friction modifier (9) The (G) organic friction modifier At least one selected from ester-based friction modifiers, amine-based friction modifiers, amide-based friction modifiers, and imide-based friction modifiers (10) Further (H) chain unsaturated (di) carboxylic (11) The component (H) is a fumaric acid alkyl ester / vinyl acetate copolymer (12) for hybrid automobiles (13), which contains a copolymer of an acid or an anhydride thereof or an ester and a vinyl compound. For electric vehicles (14) For fuel cell vehicles (15) For transmission oils (16) For gear oils

The lubricating oil composition of the present invention, the low viscosity conditions of kinematic viscosity 10 mm 2 / ^s Ultra to 20 mm 2 / ^s at 40 ° C., excellent component protection performance such as wear resistance and bearing characteristic, high electrical insulation It has properties (high volume resistivity) and excellent material compatibility. In particular, good results are obtained in the ring-on test, which is an index of seizure resistance, and the reliability is high. Therefore, it is suitably used as a transmission or gear oil for hybrid vehicles, electric vehicles, and fuel cell vehicles.

The lubricating oil composition of the present invention has a kinematic viscosity (KV40) at 40 ° C. of more than 10 to 20 mm ² / s. The lower limit of the KV40 is preferably 10.5 mm ² / s, more preferably 11 mm ² / s, and the upper limit is preferably 18 mm ² / s, more preferably 16 mm ² / s. If it exceeds the upper limit, the viscosity becomes too high and does not contribute to fuel saving performance, and if it falls below the lower limit, the wear characteristics may deteriorate.

(A) Lubricating oil base oil The lubricating oil base oil in the present invention is not particularly limited, and conventionally known lubricating oil base oils can be used. Examples of the lubricating oil base oil include mineral oil-based base oils, synthetic base oils, and mixed base oils thereof.

The method for producing mineral oil-based base oil is not limited. Mineral oil-based base oils are highly refined paraffin-based mineral oils (high-viscosity index mineral oil-based lubricating oil base oils) obtained by subjecting hydrorefined oils, catalytic isomerized oils, etc. to solvent dewaxing or hydrodewaxing. ) Is preferable. Examples of mineral oil-based base oils other than the above include raffinate obtained by solvent refining using an aromatic extraction solvent such as phenol and furfural as a lubricating oil raw material, and hydrogen such as cobalt and molybdenum using silica-alumina as a carrier. Examples thereof include hydrogenated oil obtained by hydrogenation treatment using a hydrogenation treatment catalyst. For example, 100 neutral oil, 150 neutral oil, 500 neutral oil and the like can be mentioned.

As the synthetic base oil, for example, a base oil (derived from so-called Fischer-Tropsch) obtained by hydrocracking and hydrogenating isomerizing a raw material such as wax obtained by Fischer-Tropsch synthesis from a natural gas such as methane. Base oil), poly-α-olefin base oil, polybutene, alkylbenzene, polyol ester, polyglycol ester, dibasic acid ester, phosphoric acid ester, silicon oil and the like. The poly-α-olefin (PAO) base oil is not particularly limited, and for example, 1-octene oligomer, 1-decene oligomer, ethylene-propylene oligomer, isobutene oligomer, and hydrides thereof can be used.

The lubricating oil base oil may be used alone or in combination of two or more as long as it is selected from the above-mentioned mineral oil-based base oil, the above-mentioned synthetic base oil, or a combination thereof. When two or more kinds of lubricating oil base oils are used in combination, they may be mineral oil-based base oils, synthetic base oils, or a combination of mineral oil-based base oils and synthetic base oils, and the mode thereof is not limited.

The kinematic viscosity of the lubricating oil base oil is not limited as long as the gist of the present invention is not impaired. In particular, in order to obtain the above-mentioned lubricating oil composition having a low viscosity, ^{it is preferable that the entire lubricating oil base oil has a kinematic viscosity of 1 to 4.5 mm 2} / s at 100 ° C., and more preferably 1.1. It is preferably to have ~ 4.3 mm ² / s, more preferably 1.2 to 4.0 mm ² / s. If the kinematic viscosity of the lubricating oil base oil at 100 ° C. exceeds the above upper limit value, it may be difficult to reduce the viscosity of the lubricating oil composition, and it may be difficult to achieve fuel efficiency. If the kinematic viscosity at 100 ° C. is less than the lower limit, fuel efficiency can be achieved, but the wear characteristics may be adversely affected.

(B) Metal Cleaner The lubricating oil composition of the present invention contains a metal cleanser. The metal cleaning agent is not particularly limited, but is preferably one or more of metal cleaning agents having an element selected from calcium and magnesium. As the metal cleaning agent having calcium, calcium sulfonate, calcium phenate, and calcium salicylate are preferable. One of these metal cleaning agents may be used alone, or two or more thereof may be mixed and used. As the metal cleaning agent having magnesium, magnesium sulfonate, magnesium phenate, and magnesium salicylate are preferable. Of these metal cleaning agents, at least one selected from calcium salicylate, calcium sulfonate, magnesium salicylate, and magnesium sulfonate is preferable. The metal cleaning agent may be used alone or in combination of two or more. The total base value of the metal detergent is not limited, but is preferably 50 to 600 (mgKOH / g), more preferably 100 to 500 (mgKOH / g), and even more preferably 100 to 400 (mgKOH / g). is there. The total base value is the number of milligrams (mg) of hydrochloric acid or perchloric acid equivalent to potassium hydroxide required to neutralize all the basic components contained in 1 g of the sample, such as JIS K2501. Can be measured according to.

The content of the metal cleaning agent is not particularly limited, but the metal content contained in the lubricating oil composition is preferably 10 to 500 mass ppm, more preferably 20 to 400 mass ppm, and 40 to 40 to 400 mass ppm. 300 mass ppm is more preferred. If the amount of the metal cleaning agent is too small, the material compatibility may be inferior, and if it is too large, high electrical insulation (high volume resistivity) may not be obtained, which is not preferable.

(C) Phosphorus-based extreme pressure agent The lubricating oil composition of the present invention has 1 or more selected from (C1) phosphite ester and phosphonic acid ester as (C) phosphorus-based extreme pressure agent, and (C2) 11 to 11 carbon atoms. An acidic phosphoric acid ester having 30 alkyl groups is essentially contained.

(C1) The phosphite ester or phosphonic acid ester is not particularly limited. For example, the phosphite ester has the following structure.
(R ² O) _b P (= O) (OH) _2-b H (1)
(R ³ O) _3- P (2)
In the above formulas (1) and (2), b is 1 or 2, and R ² and R ³ are hydrocarbon residues.

In the above formulas (1) and (2), R ² and R ³ are not limited as long as they are hydrocarbon residues, but are preferably alkyl groups having 4 to 30 carbon atoms, and have 4 carbon atoms. It is more preferably an alkyl group of ~ 20, and most preferably an alkyl group having 4 to 18 carbon atoms.

The phosphite ester is not particularly limited, but is phosphite tributyl ester, phosphite dibutyl ester, phosphite monobutyl ester, phosphite tripentyl ester, phosphite dipentyl ester, and phosphite. Acid monopentyl ester, phosphite trihexyl ester, phosphite dihexyl ester, phosphite monohexyl ester, phosphite triheptyl ester, phosphite diheptyl ester, phosphite monoheptyl ester, phosphite tri Octyl ester, dioctyl phosphite ester, monooctyl phosphite ester, trinonyl phosphite ester, dinonyl phosphite ester, monononyl phosphite ester, tridecyl phosphite ester, didecyl phosphite ester , Hydrate monodecyl ester, Triundecyl phosphite, Diundecyl phosphite, Monoundecyl phosphite, Tridodecyl phosphite, Didodecyl phosphite, Monododecyl phosphite Esters, tritridecyl phosphite, ditridecyl phosphite, monotridecyl phosphite, tritetradecyl phosphite, ditetradecyl phosphite, monotetradecyl phosphite, phosphite Acid tritetradecyl ester, ditetradecyl phosphite ester, monotetradecyl phosphite ester, tripentadecyl phosphite ester, dipentadecyl phosphite ester, monopentadecyl phosphite ester, tri phosphite Hexadecyl ester, dihexadecyl phosphite, monohexadecyl phosphite, triheptadecyl phosphite, diheptadecyl phosphite, monoheptadecyl phosphite, trioctadecyl phosphite , Dioctadecyl phosphite ester, monooctadecyl phosphite ester.
Among them, dibutyl phosphite ester, monobutyl phosphite ester, dihexyl phosphite ester, monohexyl phosphite ester, dioctyl phosphite ester, monooctyl phosphite ester, didecyl phosphite ester, phosphite Acid monodecyl ester, diphosphate didodecyl ester, monododecyl phosphite, ditetradecyl phosphite, monotetradecyl phosphite, dihexadecyl phosphite, monohexadecyl phosphite , Dioctadecyl phosphite ester, monooctadecyl phosphite ester are preferred.

The component (C1) may be an amine salt of a phosphite ester. The amine salt of the phosphite ester is not particularly limited, but is an amine salt of a dibutyl ester of phosphite, an amine salt of a monobutyl ester of phosphite, an amine salt of a dihexyl phosphite, and a phosphorus. Acid monohexyl ester amine salt, phosphite dioctyl ester amine salt, phosphite monooctyl ester amine salt, phosphite didecyl ester amine salt, phosphite monodecyl ester amine salt, phosphite Amine salt of didodecyl ester, amine salt of monododecyl phosphite, amine salt of ditetradecyl phosphite, amine salt of monotetradecyl phosphite, amine salt of dihexadecyl phosphite, Examples thereof include an amine salt of a monohexadecyl phosphite ester, an amine salt of a dioctadecyl phosphite ester, and an amine salt of a monooctadecyl phosphite ester.

Of the above (C1) components
The phosphonic acid ester is represented by the following formula.
(R ⁴ O) (R ⁵ O) (R ⁶ ) P (= O) (3)
In formula (3), R ⁴ and R ⁵ are independent of each other, a hydrogen atom or a monovalent hydrocarbon group, ^{at least one of R 4} and R ⁵ is a monovalent hydrocarbon group, and R ⁶ is a monovalent hydrocarbon group. It is a monovalent hydrocarbon group.

^{R 4} , R ⁵ and R ⁶ in the formula (3) are not limited as long as the above conditions are satisfied, but R ⁴ and R ⁵ are independent of each other and have one of hydrogen atoms or 1 to 30 carbon atoms. It is a valent hydrocarbon group, and ^{at least one of R 4} and R ⁵ is preferably a monovalent hydrocarbon group ^{having 1 to 30 carbon atoms, and R 6} is preferably a monovalent hydrocarbon group having 1 to 30 carbon atoms. It is more preferable that any one of R ⁴ , R ⁵ and R ⁶ is a monovalent hydrocarbon group having 4 to 30 carbon atoms.
Any of R ⁴ and R ⁵ is preferably an alkyl group having 1 to 30 carbon atoms, more preferably an alkyl group having 2 to 20 carbon atoms, and particularly preferably an alkyl group having 4 to 20 carbon atoms. .. In another preferred embodiment, R ⁴ and R ⁵ are both alkyl groups having 1 to 30 carbon atoms, and more preferably R ⁴ and R ⁵ are both alkyl groups having 2 to 20 carbon atoms, particularly having 2 to 20 carbon atoms. It is preferably an alkyl group of 4 to 20.

Examples of the phosphonic acid ester include dimethyl butylphosphonate, diethyl butylphosphonate, dipropyl butylphosphonate, dibutyl butylphosphonate, dipentyl butylphosphonate, dihexyl butylphosphonate, diheptyl butylphosphonate, dioctyl butylphosphonate, and hexylphosphone. Dimethyl oxyate, diethyl hexyl phosphonate, dipropyl hexyl phosphonate, dibutyl hexyl phosphonate, dipentyl hexyl phosphonate, dihexyl hexyl phosphonate, diheptyl hexyl phosphonate, dioctyl hexyl phosphonate, dimethyl octyl phosphonate, diethyl octyl phosphonate, octyl phosphone Dipropyl acid, dibutyl octylphosphonate, dipentyl octylphosphonate, dihexyl octylphosphonate, diheptyl octylphosphonate, dioctyl octylphosphonate, dimethyl decylphosphonate, diethyl decylphosphonate, dipropyl decylphosphonate, dibutyl decylphosphonate, decylphosphone Dihexyl acid, dioctyl decylphosphonate, didecyl decylphosphonate, dimethyl dodecylphosphonate, diethyl dodecylphosphonate, dipropyl dodecylphosphonate, dibutyl dodecylphosphonate, dihexyl dodecylphosphonate, dioctyl dodecylphosphonate, didecyl dodecylphosphonate, dodecylphosphone Didodecyl acid, dimethyl tetradecylphosphonate, diethyl tetradecylphosphonate, dipropyl tetradecylphosphonate, dibutyl tetradecylphosphonate, dihexyl tetradecylphosphonate, dioctyl tetradecylphosphonate, dodecyl tetradecylphosphonate, diddecyl tetradecylphosphonate , Tetetradecyl tetradecylphosphonate, dimethyl hexadecylphosphonate, diethyl hexadecylphosphonate, dipropyl hexadecylphosphonate, dibutyl hexadecylphosphonate, dihexyl hexadecylphosphonate, dioctyl hexadecylphosphonate, didecyl hexadecylphosphonate, hexa Didecyl decylphosphonate, ditetradecyl hexadecylphosphonate, dimethyl octadecylphosphonate, diethyl octadecylphosphonate, dipropyl octadecylphosphonate, dibutyl octadecylphosphonate, dipentyl octadecylphosphonate, dihexyl octadecylphosphonate, diheptyl octadecylphosphonate, octadecylphosphonic acid Examples thereof include dioctyl and dioctadecyl octadecylphosphonate.

The content of the component (C1) is not limited as the phosphorus content in the lubricating oil composition, but is preferably 50 to 600 ppm, more preferably 100 to 500 ppm, and even more preferably 100 to 300 ppm.

The lubricating oil composition of the present invention further essentially contains (C2) an acidic phosphoric acid ester having an alkyl group having 11 to 30 carbon atoms as a (C) phosphorus-based extreme pressure agent.

The acidic phosphoric acid ester is represented by (R ⁷ O) _a P (= O) (OH) _3-a . It can also be used as a mixture of compounds in which a = 1 or 2 in the above formula and a has a different value. In the above formula, R ⁷ is an alkyl group having 11 to 30 carbon atoms independently of each other. The alkyl group having 11 to 30 carbon atoms may be linear or branched. R ⁷ is preferably an alkyl group having 11 to 20 carbon atoms, more preferably an alkyl group having 12 to 20 carbon atoms, and further preferably an alkyl group having 12 to 18 carbon atoms.
Too few carbon atoms in the alkyl group can accelerate wear.

As the acidic phosphoric acid ester, an acidic phosphoric acid dodecyl ester, an acidic phosphoric acid tetradecyl ester, an acidic phosphoric acid hexadecyl ester, an acidic phosphoric acid octadecyl ester, and an acidic phosphoric acid eicosyl ester are preferably used. More preferably, it is an acidic phosphoric acid tetradecyl ester, an acidic phosphoric acid hexadecyl ester, and an acidic phosphoric acid octadecyl ester.

The content of the component (C2) is not limited as the phosphorus content in the lubricating oil composition, but is preferably 50 to 600 ppm, more preferably 80 to 500 ppm, and even more preferably 80 to 400 ppm.

The phosphorus content of the (C) phosphorus-based extreme pressure agent in the lubricating oil composition is not limited, but is preferably 200 to 1000 ppm, more preferably 250 to 900 ppm, and most preferably 280 to 800 ppm. is there.

(D) Sulfur-based extreme pressure agent The lubricating oil composition of the present invention contains a sulfur-based extreme pressure agent as an essential sulfur source. The content of the sulfur-based extreme pressure agent is not limited, but for example, the sulfur-based extreme pressure agent is used as a sulfur content of 100 to 500 ppm, preferably 200 to 450 ppm, based on the total mass of the lubricating oil composition. It is good to be. The component (D) may be a known sulfur-based extreme pressure agent, and is preferably at least one selected from, for example, thiadiazole, olefin sulfide, oil sulfide, sulfide ester, and polysulfide, and in particular, olefin sulfide. Thiadiazole and sulfide fats and oils are preferable. Most preferably thiadiazole.

上記式（４）〜（６）中、Ｒ^１〜Ｒ^６は、互いに独立に、水素原子又は炭素数１〜３０の一価炭化水素基であり、ａ、ｂ、ｃ、ｄ、ｅ及びｆはそれぞれ０〜８の整数である。 Thiadiazole is a nitrogen-containing sulfur heterocyclic compound, and its structure is not particularly limited. The nitrogen-containing heterocyclic compound has high adsorptivity and is preferable because a high seizure resistance improving effect can be obtained even in a small amount. For example, the 1,3,4-thiadiazole compound represented by the following general formula (4), the 1,2,4-thiadiazole compound represented by the following general formula (5), and the 1,4 represented by the general formula (6). , 5-Thiadiazole compounds.

In the above formulas (4) to (6), R ^{1 to} R ⁶ are hydrogen atoms or monovalent hydrocarbon groups having 1 to 30 carbon atoms independently of each other, and are a, b, c, d, e and f. Are integers from 0 to 8, respectively.

Examples of the hydrocarbon group having 1 to 30 carbon atoms include an alkyl group, a cycloalkyl group, an alkylcycloalkyl group, an alkenyl group, an aryl group, an alkylaryl group, and an arylalkyl group.

Examples of the thiadiazole include 2-amino-5-methyl-1,3,4-thiadiazole, 2,5-dimethyl-1,3,4-thiadiazole and 2,5-diethyl-1,3,4-thiadiazole. , 2,5-bis (n-hexyldithio) -1,3,4-thiadiazole, 2,5-bis (n-octyldithio) -1,3,4-thiadiazole, 2,5-bis (n-nonyldithio) )-1,3,4-Thiadiazole, 2,5-bis (1,1,3,3-tetramethylbutyldithio) -1,3,4-thiadiazole, 3,5-bis (n-hexyldithio)- 1,2,4-thiadiazole, 3,5-bis (n-octyldithio) -1,2,4-thiadiazole, 3,5-bis (n-nonyldithio) -1,2,4-thiadiazole, 3,5 -Bis (1,1,3,3-tetramethylbutyldithio) -1,2,4-thiadiazole, 4,5-bis (n-hexyldithio) -1,2,3-thiadiazole, 4,5-bis (N-octyldithio) -1,2,3-thiadiazole, 4,5-bis (n-nonyldithio) -1,2,3-thiadiazole, 4,5-bis (1,1,3,3-tetramethyl) Butyldithio) -1,2,3-thiadiazole and mixtures thereof can be mentioned. Of these, 2,5-bis (1,1,3,3-tetramethylbutyldithio) -1,3,4-thiadiazole is preferable.

The olefin sulfide and polysulfide are represented by, for example, the following general formula (7).
R ^8- S _x1- (R ^9- S _x2- ) _n- R ¹⁰ (7)
As will be described later, olefin sulfide is obtained by sulfurizing olefins, and polysulfide is obtained by sulfurizing a hydrocarbon raw material other than olefins.

In the above formula (7), R ⁸ and R ⁹ are monovalent hydrocarbon groups independently of each other, for example, linear or branched, saturated or unsaturated aliphatic monovalent hydrocarbons having 2 to 20 carbon atoms. It is a hydrogen group or an aromatic monovalent hydrocarbon group having 2 to 26 carbon atoms. For example, ethyl group, propyl group, butyl group, nonyl group, dodecyl group, propenyl group, butenyl group, benzyl group, phenyl group, tolyl group, hexylphenyl group and the like can be mentioned.

In the above formula (7), R ¹⁰ is a linear or branched saturated or unsaturated aliphatic divalent hydrocarbon group having 2 to 20 carbon atoms, or an aromatic divalent hydrocarbon having 6 to 26 carbon atoms. It is a hydrogen group. For example, an ethylene group, a propylene group, a butylene group, a phenylene group and the like can be mentioned.

In the above formula (7), x1 and x2 are integers of 1 or more, preferably integers of 1 to 8, independently of each other. If it is smaller than this value, the extreme pressure property becomes small, and if it is too large, the thermal oxidation stability may decrease. In order to obtain both extreme pressure and thermal oxidation stability, x2 is preferably an integer of 1 to 6, more preferably an integer of 2 to 4, and particularly preferably 2 or 3.

Examples of the sulfide olefin include those obtained by sulphurizing olefins such as polyisobutylene and terpenes with sulfur or other sulfide agents.

Examples of the polysulfide compound include diisobutyldisulfide, dioctylpolysulfide, di-tert-butylpolysulfide, and di-tert-benzylpolysulfide.

Sulfurized fats and oils are reaction products of fats and oils and sulfur, and are obtained by sulfurizing animal and vegetable fats and oils such as lard, beef tallow, whale oil, palm oil, coconut oil, and rapeseed oil as fats and oils. This reaction product is not a single product, but a mixture of various substances, and the chemical structure itself is not clear.

The sulfurized ester is obtained by sulfurizing a fatty acid ester obtained by reacting the above fats and oils with various alcohols. Like sulfide fats and oils, the chemical structure itself is not clear.

The amount of active sulfur of the sulfur-based extreme pressure agent is not particularly limited, but has active sulfur in an amount of 45% by mass or less, preferably 30% by mass or less, based on the mass of the extreme pressure agent. , More preferably, it is characterized by having 15% by mass or less. If the amount of active sulfur exceeds the above upper limit, not only metal corrosion occurs, but also wear cannot be suppressed. The lower limit of the amount of active sulfur is not particularly limited, but in order to ensure extreme pressure, it is preferably 0.5% by mass or more, more preferably 1% by mass, based on the mass of the extreme pressure agent. % Or more, more preferably 2% by mass or more.

Here, the amount of active sulfur is measured by the method specified in ASTM D1662. The amount of active sulfur based on ASTM D1662 can be measured in more detail by the following procedure.
Put 50 g of a sulfur-based additive (active sulfur-based extreme pressure agent) and 5 g of copper powder in a beaker for 1.200 ml, and raise the temperature to 150 ° C. while stirring with a stirrer.
2. When the temperature reaches 150 ° C., add 5 g of copper powder and stir for 30 minutes.
3. 3. After the stirring is completed, an ASTM D130 compliant copper plate is placed in a beaker and immersed. At this time, if discoloration is observed on the copper plate, add 5 g of copper powder and stir for 30 minutes (continue this operation until discoloration is no longer observed).
4. When the discoloration of the copper plate is no longer observed, the copper powder in the sulfur-based additive is removed by filtration, and the amount of sulfur contained in the additive is measured.
The amount of active sulfur is calculated as follows.
Amount of active sulfur (% by mass) = Amount of sulfur before reaction with copper powder (% by mass) -Amount of sulfur after reaction with copper powder (% by mass)

式中、Ｒは、互いに独立に、炭素数６〜１４のα−オレフィンから導かれる繰り返し単位を有するポリα−オレフィン構造であり、ａは１〜１０の整数である。Ｒは好ましくは、１−オクテン、１−デセン、又は１−ドデセン、及びこれらの混合を繰り返し単位として含む炭素数２０〜１０００、好ましくは炭素数３０〜８００のポリα―オレフィン構造である。上記化合物は重量平均分子量１，０００〜１０，０００、好ましくは１，５００〜５，０００を有する。 (E) Ash-free dispersant The lubricating oil composition of the present invention has (E) an ash-free dispersant, and as the (E) ash-free dispersant, (E1) contains a poly α-olefin represented by the following formula (poly). An imide of ethyleneamine succinimide and a boronized product of the imide polyα-olefin succinimide having (E2) weight average molecular weight (Mw) of 1500 to 4500 are essentially contained.

In the formula, R is a polyα-olefin structure having repeating units derived from α-olefins having 6 to 14 carbon atoms independently of each other, and a is an integer of 1 to 10. R is preferably a poly-α-olefin structure having 20 to 1000 carbon atoms, preferably 30 to 800 carbon atoms, containing 1-octene, 1-decene, or 1-dodecene, and a mixture thereof as a repeating unit. The compound has a weight average molecular weight of 1,000 to 10,000, preferably 1,500 to 5,000.

The polyethyleneamine succinimide may be produced by a known method. For example, it can be produced by the method described in JP-A-2017-25306. More specifically, the hydrocarbon group obtained by polymerizing a mixture of 1-octene, 1-decene and 1-dodecene with a metallocene catalyst is reacted with maleic anhydride, and then the obtained reaction product is reacted with polyethyleneamine. Obtained by

The content of the component (E1) in the lubricating oil composition is 0.5 to 3.5% by mass, preferably 0.5 to 2.5% by mass, and more preferably 0.5 to 1%. It is 5.5% by mass.

In addition to the component (E1), the lubricating oil composition of the present invention contains a boronized product of polyα-olefin succinimide having (E2) a weight average molecular weight (Mw) of 1500 to 4500. The component (E2) is, for example, a boronized product of succinimide having at least one alkyl group or alkenyl group having a linear structure or a branched structure and having 40 to 400 carbon atoms in the molecule. The ashless dispersant may be used alone or in combination of two or more. The boronized succinimide is a boronized succinimide generally used for lubricating oil, and may be any conventionally known boronized succinimide. Borylation is usually carried out by allowing boric acid to act on the nitrogen-containing compound to neutralize some or all of the remaining amino and / or imino groups. In the present invention, the borated succinimide is characterized by having a weight average molecular weight of 1500 to 4500, preferably having a weight average molecular weight of 2000 to 4000.

The alkyl group or alkenyl group of the poly-α-olefin succinimide has 40 to 400 carbon atoms, preferably 60 to 350 carbon atoms. When the number of carbon atoms of the alkyl group and the alkenyl group is less than the above lower limit value, the solubility of the compound in the lubricating oil base oil tends to decrease. Further, when the carbon number of the alkyl group and the alkenyl group exceeds the above upper limit value, the low temperature fluidity of the lubricating oil composition tends to deteriorate. The alkyl group and the alkenyl group may have a linear structure or a branched structure. Preferred embodiments include, for example, olefin oligomers such as propylene, 1-butene, isobutylene, hexene, octene, decene, dodecene, branched alkyl groups or branched alkenyl groups derived from ethylene and propylene co-oligomers, and the like. Can be mentioned.

The succinimide includes a so-called monotype succinimide in which succinic anhydride is added to one end of the polyamine, and a so-called bis-type succinimide in which succinic anhydride is added to both ends of the polyamine. The lubricating oil composition of the present invention may contain either monotype or bistype, or may contain both. One type of boronized succinimide may be used alone, or two or more types may be used in combination. When used in combination, both monotype and bistype may be included, monotypes may be used in combination, or bistypes may be used in combination.

Examples of the method for producing an imide boronated succinimide are disclosed in Japanese Patent Application Laid-Open No. 42-8013 and 42-8014, Japanese Patent Application Laid-Open No. 51-52381, and Japanese Patent Application Laid-Open No. 51-130408. The method used is mentioned. More specifically, an organic solvent such as alcohols, hexane, and xylene, a polyamine as a base oil for a light lubricating oil, and a boron compound such as boric acid, borate ester, or borate as polyalkenyl succinic acid (anhydrous). It can be obtained by mixing and heat-treating under appropriate conditions. The boron content of the boronized succinimide thus obtained can be usually 0.1 to 4% by mass. In particular, a boron-modified compound (borated succinimide) of an alkenyl succinimide compound is preferable because it is excellent in heat resistance, antioxidant property and wear resistance.

The boron content contained in the boronized ashless dispersant is not particularly limited, but the amount of the boron content contained in the lubricating oil composition is preferably 25 to 150 mass ppm. For example, if the amount of boron contained in the ashless dispersant increases, the amount of the boborated ashless dispersant added to the lubricating oil composition is naturally limited. Usually, it is 0.1 to 3% by mass with respect to the mass of the ashless dispersant. In one aspect of the present invention, the boron content in the ashless dispersant is preferably 0.2% by mass or more, more preferably 0.4% by mass or more, and preferably 2% by mass or less, more preferably. Is 1.5% by mass or less, more preferably 1.0% by mass or less. The boronized ashless dispersant is preferably an imide borated succinimide, and particularly preferably an imide borated bisuccinate. When a borated ashless dispersant is used, its boron content is 0.01% by mass or more, preferably 0.02% by mass or more, more preferably 0.025% by mass or more, based on the total mass of the composition. It is preferable that it is 0.15% by mass or less, preferably 0.1% by mass or less, and particularly preferably 0.05% by mass or less.

The boronized ashless dispersant has a boron / nitrogen mass ratio (B / N ratio) of 0.1 or more, preferably 0.2 or more, preferably less than 0.5, more preferably 0.4 or less. It is preferable to have.

In the present invention, an unborated unmodified ashless dispersant other than the components (E1) and (E2) can be further used in combination. Examples of the non-borylated ashless dispersant include the above-mentioned alkenyl succinimide compounds that are not boronized. It is preferable to use a mixture of a boronized product of bisimide polyisobutenyl succinate and unmodified bisimide polyisobutenyl succinate.

The content of the ashless dispersant in the lubricating oil composition may be appropriately adjusted. For example, the total of the above (E1) component and (E2) component is 0.01 with respect to the total mass of the lubricating oil composition. It is preferably ~ 20% by mass, more preferably 0.1 to 10% by mass. If the content of the ashless dispersant is less than the above lower limit, the effect of improving cleanliness may be insufficient. If the content exceeds the above upper limit, sludge of the lubricating oil composition may be generated.

The boron content in the lubricating oil composition is 25 to 150 mass ppm, preferably 30 to 120 mass ppm.

(F) Viscosity Index Improver The lubricating oil composition of the present invention indispensably contains a viscosity index improver. In the present invention, the viscosity index improver has a weight average molecular weight of 10,000 to 100,000. It is preferably 15,000 to 80,000, and more preferably 15,000 to 50,000. If the weight average molecular weight is less than the above lower limit value, the heat-resistant seizure property of the obtained lubricating oil composition may deteriorate, and if it exceeds the above upper limit value, the kinematic viscosity at 40 ° C. in the lubricating oil composition tends to increase. , It becomes difficult to contribute to fuel saving.
The weight average molecular weight of the viscosity index improver was measured by GPC (gel permission chromatography) under the following conditions and converted to polystyrene.
Equipment: "HLC-802A" [manufactured by Tosoh Corporation]
Column: 2 "TSK gel GMH6" [manufactured by Tosoh Corporation] Measurement temperature: 40 ° C
Sample solution: 0.25 wt% tetrahydrofuran solution Injection volume: 100 μl
Detector: Refractive index detector

The viscosity index improver may have a weight average molecular weight within the above range, and may be appropriately selected from conventionally known viscosity index improvers. For example, a so-called non-dispersive viscosity index improver such as a polymer or copolymer of one or more kinds of monomers selected from various methacrylic acid esters, or a hydrogenated product thereof, or various kinds containing a nitrogen compound. A so-called dispersed viscosity index improver obtained by copolymerizing a methacrylic acid ester, a non-dispersed or dispersed ethylene-α-olefin copolymer (examples of α-olefin include propylene, 1-butene, 1-pentene and the like). , Or a hydride thereof, polyisobutylene or a hydrogenated product thereof, a hydride of a styrene-diene copolymer, polyalkylstyrene and the like, and examples thereof include a polymer having a methacrylic acid ester (PMA) and an ethylene-α-olefin. Copolymers are preferable, and polymers having a methacrylic acid ester (PMA) are most preferable. The amount of the viscosity index improver added to the lubricating oil composition is not limited, but is preferably 0.1 to 15% by mass, more preferably 1 to 10% by mass, still more preferably 2 to 8% by mass. Most preferably, 3 to 7% by mass.

(G) Organic Friction Modifier The lubricating oil composition of the present invention may further contain an organic friction modifier as an optional component. The organic friction modifier means a friction modifier having no metal. For example, it is composed of an organic compound such as an amine-based friction modifier, an amide-based friction modifier, an ester-based friction modifier, an ether-based friction modifier, and an imide-based friction modifier. Particularly preferably, it is an amine-based friction modifier, an ester-based friction modifier, or an imide-based friction modifier, and functions suitably as a phosphorus scavenger. By including the organic friction modifier, excellent wear resistance and seizure resistance can be ensured. When an organic friction modifier is added, the content in the lubricating oil composition is preferably 0.1 to 2% by mass, more preferably 0.2 to 1.5% by mass, and even more preferably 0. It is 2-1% by mass. The organic friction modifier may be used alone or in combination of two or more.

As the amine-based friction modifier, an aliphatic amine compound is preferable. Examples of the aliphatic amine compound include alkylamines having an alkyl group having 1 to 30 carbon atoms, alkenylamines having an alkenyl group having 2 to 30 carbon atoms, alkylenediamine having an alkylene group having 1 to 30 carbon atoms, and carbon. Polyamines having an alkyl group of several 1 to 30 and an alicyclic amine can be mentioned.

In an alkylamine having an alkyl group having 1 to 30 carbon atoms, the alkyl group may be linear or may have a branch. The alkyl group preferably has 4 to 28 carbon atoms, and more preferably 6 to 25 carbon atoms. For example, methylamine, ethylamine, propylamine, butylamine, pentylamine, hexylamine, heptylamine, octylamine, nonylamine, decylamine, undecylamine, dodecylamine (laurylamine), tridecylamine, tetradecylamine, pentadecylamine. , Hexadecylamine, heptadecylamine, octadecylamine (stearylamine), docosylamine (behenylamine), dimethylamine, diethylamine, dipropylamine, dibutylamine, dipentylamine, dihexylamine, diheptylamine, dioctylamine, dinonylamine, didecylamine , Diundecylamine, didodecylamine, ditridecylamine, ditetradecylamine, dipentadecylamine, dihexadecylamine, diheptadecylamine, dioctadecylamine, methylethylamine, methylpropylamine, methylbutylamine, ethylpropylamine , Ethylbutylamine, and propylbutylamine.

In an alkenylamine having an alkenyl group having 2 to 30 carbon atoms, the alkenyl group may be linear or branched. The alkenyl group preferably has 4 to 28 carbon atoms, and more preferably 6 to 25 carbon atoms. For example, ethenylamine, propenylamine, butenylamine, octenylamine, and oleylamine can be mentioned.

In an alkylene diamine having an alkylene group having 1 to 30 carbon atoms, the alkylene group may be linear or branched. For example, methylenediamine, ethylenediamine, propylenediamine, and butylenediamine can be mentioned.

In a polyamine having an alkyl group having 1 to 30 carbon atoms, the alkyl group may be linear or branched. For example, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, and pentaethylenehexamine can be mentioned.

Examples of the alicyclic amine include cyclohexylamine and the like.

The amide-based friction modifier is not limited, but it is preferable to use a saturated fatty acid amide having an alkyl group having 1 to 30 carbon atoms and an unsaturated fatty acid amide having an alkenyl group having 2 to 30 carbon atoms. ..
These may be used alone or in combination.

Saturated fatty acid amides having an alkyl group having 1 to 30 carbon atoms include ethane acid amide, propanoic acid amide, butanoic acid amide, octanoic acid amide, decanoic acid amide, dodecanoic acid amide, hexadecanoic acid amide, octadecanoic acid amide, and docosanoic acid. Amides can be mentioned. The number of carbon atoms of the alkyl group having 1 to 30 carbon atoms is preferably 4 to 28, and more preferably 6 to 25 carbon atoms.

Examples of the unsaturated fatty acid amide having an alkenyl group having 2 to 30 carbon atoms include oleic acid amide and erucic acid amide. The alkenyl group having 2 to 30 carbon atoms preferably has 4 to 28 carbon atoms, and more preferably 6 to 25 carbon atoms.

As the ester-based friction modifier, a fatty acid ester-based friction modifier is preferable. As the fatty acid, a fatty acid having an alkyl group having 1 to 30 carbon atoms or an alkenyl group having 2 to 30 carbon atoms is preferable. The alkenyl group may be linear or has a branch, but a linear group is preferable. The alcohol to be reacted with the fatty acid in preparing the fatty acid ester may be a monohydric alcohol or a polyhydric alcohol, but a polyhydric alcohol is preferable. For example, it is a polyhydric alcohol having a value of 2 to 10 and more specifically, ethylene glycol, diethylene glycol, polyethylene glycol (3 to 15-mer of ethylene glycol), propylene glycol, dipropylene glycol, polypropylene glycol (3 of propylene glycol). ~ 15 mer), 1,3-propanediol, 1,2-propanediol, 1,3-butanediol, 1,4-butanediol, 2-methyl-1,2-propanediol, 2-methyl-1 , 3-Propanediol, 1,2-Pentanediol, 1,3-Pentanediol, 1,4-Pentanediol, 1,5-Pentanediol, dihydric alcohols such as neopentylglycol, glycerin, polyglycerin (of glycerin) 2 to 8 mer, such as diglycerin, triglycerin, tetraglycerin, etc.), trimethylol alkane (trimethylol ethane, trimethylol propane, trimethylol butane, etc.) and these 2 to 8 mer, pentaerythritol and 2 of these. ~ Quadrate, 1,2,4-butanetriol, 1,3,5-pentanetriol, 1,2,6-hexanetriol, 1,2,3,4-butantetrol, sorbitol, sorbitan, sorbitol glycerin Condensates, polyhydric alcohols such as adonitol, arabitol, xylitol, mannitol, xylose, arabinose, ribose, ramnorse, glucose, fructose, galactose, mannose, sorbose, cellobiose, maltose, isomaltose, trehalose, sculose and other sugars, Examples thereof include a mixture of.

Among the above polyhydric alcohols, ethylene glycol, diethylene glycol, polyethylene glycol (3 to 10-mer of ethylene glycol), propylene glycol, dipropylene glycol, polypropylene glycol (3 to 10-mer of propylene glycol), 1,3-propane. Diol, 2-methyl-1,2-propanediol, 2-methyl-1,3-propanediol, neopentyl glycol, glycerin, diglycerin, triglycerin, trimethylalcohol (trimethylolethane, trimethylolpropane, trimethylol) Butane etc.) and their 2 to tetramers, pentaerythritol, dipentaerythritol, 1,2,4-butanetriol, 1,3,5-pentanetriol, 1,2,6-hexanetriol, 1,2, 2,6-valent polyhydric alcohols such as 3,4-butantetrol, sorbitol, sorbitan, sorbitol glycerin condensate, adonitol, arabitol, xylitol, and mannitol, and mixtures thereof are preferable. Further, ethylene glycol, propylene glycol, neopentyl glycol, glycerin, trimethylolethane, trimethylolpropane, and mixtures thereof are more preferable. Of these, glycerin is particularly preferable.

As an ester-based friction modifier, for example, with a fatty acid selected from lauric acid, myristic acid, palmitic acid, palmitic acid, stearic acid, oleic acid, linoleic acid, linolenic acid, eicosanoic acid, behenic acid, and lignoceric acid or a mixture thereof. , Ethyl glycol, propylene glycol, neopentyl glycol, glycerin, trimethylolethane, trimethylolpropane, and esters obtained by reacting alcohols selected from them or mixtures thereof. The structure of the ester may be a complete ester in which all the hydroxyl groups in the polyhydric alcohol are esterified, or a partial ester in which a part of the hydroxyl groups is not esterified and remains as the hydroxyl groups. Of these, partial esters of fatty acids and glycerin having 16 to 20 carbon atoms are preferable.

More preferably, as the ester-based friction modifier, glycerin monooleate, glycerin monostearate, glycerin monolaurate, ethylene glycol monooleate, ethylene glycol monostearate, ethylene glycol monolaurate, propylene glycol monooleate, propylene glycol mono. Examples thereof include esterate and propylene glycol monolaurate. Of these, glycerin monooleate, glycerin monostearate, and glycerin monolaurate are particularly preferable.

Further, examples of the ether-based friction modifier include ether compounds having two or more hydroxyl groups in the molecule, and a (poly) glycerin ether compound is preferable. For example, it is expressed by the following formula (8).
R ^11- O- (CH _2- CH (OH) -CH _2- O) _p- H (8)
In the above formula (8), R ¹¹ is a monovalent hydrocarbon group having 1 to 30 carbon atoms, for example, an alkyl group having 1 to 30 carbon atoms, an alkenyl group having 3 to 30 carbon atoms, and an aryl having 6 to 30 carbon atoms. Examples include a group and an aralkyl group having 7 to 30 carbon atoms. The alkyl group and alkenyl group may be linear, branched, or cyclic. p is an integer of 1-10. Particularly preferably, R ¹¹ is preferably an alkyl group or an alkenyl group having 8 to 20 carbon atoms from the viewpoint of the performance and availability of the (poly) glycerin ether compound.

Examples of the alkyl group having 1 to 30 carbon atoms, preferably 8 to 20 carbon atoms include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, isopentyl, neopentyl, tert-pentyl, hexyl and heptyl. , Octyl, 2-ethylhexyl, nonyl, decyl, undecyl, dodecyl, tridecyl, isotridecyl, tetradecyl, hexadecyl, octadecyl, icosyl, docosyl, tetracocil, triacontyl, 2-octyldodecyl, 2-dodecylhexadecyl, 2-tetradecyl octadecyl, Groups such as 16-methylheptadecyl, cyclopentyl, cyclohexyl, methylcyclohexyl, and cyclooctyl can be mentioned.

Examples of the alkenyl group having 3 to 30 carbon atoms, preferably 8 to 20 carbon atoms include a propenyl group, an isopropenyl group, a butenyl group, an isobutenyl group, a pentanyl group, an isopentenyl group, a hexenyl group, a heptenyl group, an octenyl group and a nonenyl group. , Decenyl group, undecenyl group, dodecenyl group, tetradecenyl group, octadecenyl group, oleyl group, cyclopentenyl group, cyclohexenyl group, methylcyclopentenyl group, methylcyclohexenyl group and the like.

Examples of the aryl group having 6 to 30 carbon atoms include a phenyl group, a naphthyl group, a tolyl group, a xsilyl group, a cumenyl group, a mesityl group, an ethylphenyl group, a propylphenyl group, a butylphenyl group, a pentylphenyl group, a hexylphenyl group and a heptyl group. Examples thereof include a phenyl group, an octylphenyl group, a nonylphenyl group and the like.

Examples of the aralkyl group having 7 to 30 carbon atoms include a benzyl group, a phenethyl group, a naphthylmethyl group, a benzhydryl group, a trityl group, a methylbenzyl group, a methylphenethyl group and the like.

Examples of the (poly) glycerin ether compound include glycerin monododecyl ether, glycerin monotetradecyl ether, glycerin monohexadecyl ether (same as “chimil alcohol”), and glycerin monooctadecyl ether (same as “bacyl alcohol”). ), Glycerin monooleyl ether (same as "Ceraquil alcohol"), diglycerin monododecyl ether, diglycerin monotetradecyl ether, diglycerin monohexadecyl ether, diglycerin monooctadecyl ether, diglycerin monooleyl ether, Examples thereof include triglycerin monododecyl ether, triglycerin monotetradecyl ether, triglycerin monohexadecyl ether, triglycerin monooctadecyl ether, and triglycerin monooleyl ether.

Further, as the imide-based friction modifier, a mono and / or bisuccinate imide having one or two linear, branched, preferably branched hydrocarbon groups, and boric acid in the succinic imide. And phosphoric acid, carboxylic acid having 1 to 20 carbon atoms, or a succinic acid imide-modified compound other than the above-mentioned (E1) component and (E2) component obtained by reacting one or more selected from sulfur-containing compounds. I can get it. More specifically, compounds of the following formulas (9) and (10) can be mentioned.

In the above general formulas (9) and (10), R ¹ and R ² individually represent an alkyl group or an alkenyl group having 8 to 30, preferably 12 to 24 carbon atoms, respectively, and R ³ and R ^{4 respectively.} are each independently 1 to 4 carbon atoms, preferably an alkylene group having 2 to 3 carbon atoms, ^{R 5} is a hydrogen atom or 1 to 30 carbon atoms, preferably an alkyl or alkenyl group having 8 to 30 carbon atoms , N represents an integer of 1 to 7, and is preferably an integer of 1 to 3. Of these, the bisimide compound of the general formula (9) is preferable. When the ^{number of carbon atoms of R 1} and R ² is 40 or more, it corresponds to the above-mentioned component (E2) and is therefore excluded.

一般式（１１）において、ｘ及びｙは、ｘ＋ｙが８〜１５となる整数であり、ｚは０〜５の整数であって、好ましくはｘ及びｙは、ｘ＋ｙが１０〜１４となる整数であり、ｚは０〜３の整数である。
本摩擦調整剤は、ポリエチレンポリアミン由来のイミド系摩擦調整剤であり、その製法は、ＵＳ ５，８４０，６６３に記載されている。 Among the bisimide compounds of the general formula (9), the succinimide compound represented by the following general formula (11) is preferable.

In the general formula (11), x and y are integers in which x + y is 8 to 15, z is an integer from 0 to 5, and preferably x and y are integers in which x + y is 10 to 14. Yes, z is an integer from 0 to 3.
This friction modifier is an imide-based friction modifier derived from polyethylene polyamine, and its production method is described in US 5,840,663.

The imide-based friction modifier may be used alone, but it is preferable to use the above-mentioned amine-based friction modifier and the imide-based friction modifier in combination.

(H) Copolymer of a chain unsaturated (di) carboxylic acid or an anhydride or ester thereof and a vinyl compound The lubricating oil composition of the present invention is, if necessary, a chain unsaturated (di) carboxylic acid. Alternatively, an anhydride thereof or an ester thereof and a copolymer of a vinyl compound may be further contained. The component functions as a pour point lowering agent. By including the component, the Brookfield viscosity at −40 ° C. can be controlled in the range of 6 to 12 Pa · s. In particular, even when mixed with a commercially available oil, a decrease in Brookfield viscosity at −40 ° C. can be suppressed.

（ｎ及びｍは、重量平均分子量が５，０００〜３００，０００となる数であり、Ｒ^２は互いに独立に炭素数１〜２４のアルキル基であり、Ｒ^３は炭素数１〜１８のアルキル基であり、好ましくはメチル基である） Examples of the chain unsaturated (di) carboxylic acid or its anhydride or its ester include fumaric acid, maleic acid, fumaric acid anhydride, maleic anhydride, fumaric acid alkyl ester, and maleic acid alkyl ester, and alkyl fumarate. Esters and alkyl maleic acids are particularly preferred. Examples of the vinyl compound include α-olefins such as ethylene and propylene, and vinyl carboxylate such as vinyl acetate, and vinyl carboxylate is preferable. Vinyl carboxylate is ^{a compound represented by R 3-} COO-CH = CH ₂ , but in the present invention, R is preferably a short-chain alkyl group having 1 to 18 carbon atoms, and particularly preferably vinyl acetate in which R is a methyl group. Is.
The weight average molecular weight of the copolymer is not limited, but is preferably 5,000 to 300,000. The component (H) is preferably an ester-based copolymer, which can suitably suppress a decrease in low-temperature viscosity when mixed with a commercially available oil. The ester-based copolymer is represented by the following formula.

(N and m are numbers having a weight average molecular weight of 5,000 to 300,000, R ² is an alkyl group having 1 to 24 carbon atoms independently of each other, and R ³ is an alkyl group having 1 to 18 carbon atoms. Group, preferably methyl group)

Of these, a copolymer of an alkyl fumarate and vinyl acetate is preferable, and the ratio of the repeating unit (n) derived from the alkyl fumarate and the repeating unit (m) derived from vinyl acetate is 10:90 to 90:10 (mass). The ratio) is preferable, and 20:80 to 80:20 (mass ratio) is more preferable.

When the component (H) is added, the amount of the component (H) added is not particularly limited, but is preferably 0.02 to 3.0% by mass, preferably 0.05 to 1.5% by mass, based on the lubricating oil composition.

Further, the lubricating oil composition of the present invention may further contain a pour point lowering agent other than the above polymer. The pour point lowering agent used in combination may be any conventionally known one, and is not particularly limited.

(I) Other Additives The lubricating oil composition of the present invention contains, as other additives other than the above components (A) to (H), an antiwear agent, an antioxidant, a corrosion inhibitor, a rust preventive, and an anti-corrosion agent. It can contain an emulsifier, a metal inactivating agent, a defoaming agent, a metal friction modifier and the like.

Examples of the corrosion inhibitor include benzotriazole-based, tolyltriazole-based, and imidazole-based compounds.

Examples of the rust preventive include petroleum sulfonate, alkylbenzene sulfonate, dinonylnaphthalene sulfonate, alkenyl succinic acid ester, polyhydric alcohol ester and the like.

Examples of the anti-emulsifier include polyalkylene glycol-based nonionic surfactants such as polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, and polyoxyethylene alkyl naphthyl ether.

Examples of the metal inactivating agent include imidazoline, pyrimidine derivative, mercaptobenzothiazole, benzotriazole or a derivative thereof, 1,3,4-thiadiazole polysulfide, 1,3,4-thiadiazolyl-2,5-bisdialkyldithiocarbamate. , 2- (alkyldithio) benzimidazole, β- (o-carboxybenzylthio) propionnitrile and the like.

Examples of the defoaming agent include silicone oil having a kinematic viscosity of 10 to 100,000 mm ² / s at 25 ° C., an alkenyl succinic acid derivative, an ester of a polyhydroxy fatty alcohol and a long chain fatty acid, methyl salicylate and o-. Hydroxybenzyl alcohol and the like can be mentioned.

As the metal friction modifier, a known molybdenum friction modifier can be used. For example, a sulfur-containing organic molybdenum compound such as molybdenum dithiophosphate (MoDTP) and molybdenum dithiocarbamate (MoDTC), a complex of a molybdenum compound and a sulfur-containing organic compound or another organic compound, or molybdenum sulfide or molybdenum sulfide acid. Examples thereof include a complex of a sulfur-containing molybdenum compound such as alkenyl succinate imide and the like. Further, as the friction modifier in the present invention, the trinuclear molybdenum compound described in US Pat. No. 5,906,968 can also be used.

The lubricating oil composition of the present invention is a kinematic viscosity (KV40) is 10 super to 20 mm ² / s at 40 ° ^C., is preferably ^{10.5mm 2 / s~18mm 2 / s,} 11mm 2 / s~ It is more preferably 16 mm ^{2 / s.} If the viscosity is lower than this, the seizure resistance may not be sufficient, and if the viscosity is higher than this, it does not contribute to fuel efficiency. Further, the lubricating oil composition of the present invention is excellent in component protection performance such as wear resistance, seizure resistance, gear fatigue resistance, and bearing fatigue resistance even if the viscosity is lowered, and has high electrical insulation (high volume resistance). ) And excellent material compatibility, it can be used as a lubricating oil for hybrid vehicles, electric vehicles, and fuel cell vehicles, and in particular, it should be used as a lubricating oil for transmission oils and gear oils. Can be done.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples.

(A) Lubricating oil base oil (A1) Highly refined mineral oil-based base oil (defined as "mineral oil 2") (kinematic viscosity at 100 ° C. = 2.3 mm ² / s, viscosity index = 100,% Cp = 70,% Cn = 30,% Ca = 0)
(A2) GTL base oil (defined as "GTL4") (kinematic viscosity at 100 ° C. = 4.0 mm ² / s, viscosity index = 120,% Cp = 99,% Cn = 1,% Ca = 0)
(A3) Polyα-olefin (PAO) base oil (defined as “PAO4”) (kinematic viscosity at 100 ° C. = 4.0 mm ² / s, viscosity index = 130,% Cp = 100,% Cn = 0,% Ca = 0)

（式中、Ｒはポリデシル基であり、ａが１〜５の化合物の混合物である）
（Ｅ２）ホウ素化コハク酸イミド
（Ｅ２−１）ポリイソブチレンコハク酸イミドのホウ素化物（重量平均分子量２２００、ホウ素含有量１．０質量％）[以下、「ホウ素化コハク酸イミド１」という。]
（Ｅ２−２）ポリイソブチレンコハク酸イミドのホウ素化物（重量平均分子量１００００、ホウ素含有量１．０質量％、比較用）[以下、「ホウ素化コハク酸イミド２」という。]
（Ｅ２−３）ポリイソブチレンコハク酸イミドのホウ素化物（重量平均分子量１０００、ホウ素含有量 １．０質量％、比較用）[以下、「ホウ素化コハク酸イミド３」という。]
（Ｆ）粘度指数向上剤
（Ｆ１）ポリメタクリレート（Ｍｗ＝３０，０００）[以下、「ＰＭＡ１」という。]
（Ｆ２）ポリメタクリレート（Ｍｗ＝７０，０００）[以下、「ＰＭＡ２」という。]
（Ｆ３）エチレン・α−オレフィンコポリマー（Ｍｗ＝４０，０００）[以下、「ＥＰＣ」という。]
（Ｆ４）ポリメタクリレート（Ｍｗ＝１５０，０００）（比較用）[以下、「ＰＭＡ３」という。]
（Ｇ）有機摩擦調整剤
（Ｇ１）オレイルアミン
（Ｇ２）Ｎ，Ｎ−ジオキシエチレン−Ｎ−オレイルアミン
（Ｇ３）オレイン酸アミド
（Ｇ４）グリセリンモノオレート
（Ｇ５）ポリエチレンポリアミン由来の下記の式で表されるコハク酸イミド
(以下、「ポリエチレンポリアミン由来コハク酸イミド」という。)

式において、ｘ＋ｙ＝１３、ｚ＝０又は３の化合物の混合物。
（Ｈ）流動点降下剤
フマル酸アルキルエステル・酢酸ビニル共重合体（フマル酸アルキルエステル：酢酸ビニル＝２０：８０、重量平均分子量２０，０００）［フマル酸アルキルエステルは、フマル酸ジメチルを主成分とする混合物］
（Ｉ）その他の添加剤
酸化防止剤、金属不活性化剤、及び消泡剤のパッケージ (B) Metal cleaning agent (B1) Calcium salicylate (calcium content; 10% by mass, base value 400 mgKOH / g)
(B2) Calcium sulfonate (calcium content; 10% by mass, base value 350 mgKOH / g)
(C) Phosphorus-based extreme pressure agent
(C1) Phosphorous acid ester or phosphonic acid ester (C1-1) Phosphorous acid monobutyl ester (C1-2) Phosphorous acid monooctadecyl ester (C1-3) Phosphorous acid dibutyl ester (C1-4) Phosphorous acid Acid dioctadecyl ester (C1-5) Phosphonate monooctadecyl ester
(C2) Acidic phosphoric acid ester having an alkyl group having 11 to 30 carbon atoms (also referred to as a long-chain alkyl group-containing acidic phosphoric acid ester)
(C2-1) Acidic Phosphate Octadecyl Ester (C2-2) Acidic Phosphate Dodecyl Ester (C2-3) Acidic Phosphate Tetradecyl Ester
(C3) Acidic phosphoric acid ester having an alkyl group having 10 or less carbon atoms ( also referred to as a short-chain alkyl group-containing acidic phosphoric acid ester. For comparative examples)
(C3-1) Acidic Phosphate Butyl Ester
(D) Sulfur-based extreme pressure agent (D1) 2,5-bis (1,1,3,3-tetramethylbutyldithio) -1,3,4-thiadiazole (active sulfur amount; 3.3% by mass) [ Hereinafter, it is simply referred to as "thiadiazole". ]
(D2) Olefin Sulfide (Amount of Active Sulfur; 11% by Mass)
(D3) Sulfate ester (Amount of active sulfur; 1.4% by mass)
(D4) Sulfide fats and oils (amount of active sulfur; 4.1% by mass)
(E) Ash-free dispersant
(E1) Polyalkyl (Poly) Ethyleneamine Succinimide
(E1-1) Polydecyl group-containing (poly) ethyleneamine succinimide (weight average molecular weight 2000) represented by the following formula [hereinafter referred to as "succinimide 1". ]
(E1-2) Polydecyl group-containing (poly) ethyleneamine succinimide (weight average molecular weight 4000) represented by the following formula [hereinafter referred to as "succinimide 2". ]

(In the formula, R is a polydecyl group and a is a mixture of compounds 1 to 5)
(E2) Borylated succinimide (E2-1) Borylated polyisobutylene succinimide (weight average molecular weight 2200, boron content 1.0% by mass) [Hereinafter referred to as "borated succinimide 1". ]
(E2-2) Boronized polyisobutylene succinimide (weight average molecular weight 10000, boron content 1.0% by mass, for comparison) [Hereinafter referred to as "boronated succinimide 2". ]
(E2-3) Boronized polyisobutylene succinimide (weight average molecular weight 1000, boron content 1.0% by mass, for comparison) [Hereinafter referred to as "borated succinimide 3". ]
(F) Viscosity index improver (F1) Polymethacrylate (Mw = 30,000) [Hereinafter referred to as "PMA1". ]
(F2) Polymethacrylate (Mw = 70,000) [hereinafter referred to as "PMA2". ]
(F3) Ethylene-α-olefin copolymer (Mw = 40,000) [hereinafter referred to as "EPC". ]
(F4) Polymethacrylate (Mw = 150,000) (for comparison) [Hereinafter referred to as "PMA3". ]
(G) Organic Friction Modifier (G1) Oleylamine (G2) N, N-Dioxyethylene-N-Oleylamine (G3) Oleic Acid Amide (G4) Glycerin Monooleate (G5) Represented by the following formula derived from polyethylene polyamine Succinimide
(Hereinafter referred to as "polyethylene polyamine-derived succinimide")

In the formula, a mixture of compounds of x + y = 13, z = 0 or 3.
(H) Pour point depressant
Fumaric acid alkyl ester / vinyl acetate copolymer (Fumaric acid alkyl ester: vinyl acetate = 20: 80, weight average molecular weight 20,000) [Fumaric acid alkyl ester is a mixture containing dimethyl fumarate as a main component]
(I) Other Additives Packages for Antioxidants, Metal Inactivating Agents, and Defoamers

[Examples 1 to 19 and Comparative Examples 1 to 14]
The above-mentioned components were mixed in the compositions and amounts shown in Tables 1 to 3 to prepare lubricating oil compositions in Examples and Comparative Examples. The amount of the metal cleaning agent of the component (B) shown in the table is the mass ppm of the metal element (Ca) with respect to the mass part of the entire lubricating oil composition. The amount of the phosphorus-based extreme pressure agent of the component (C) is the mass ppm of phosphorus with respect to the mass part of the entire lubricating oil composition. The amount of the sulfur-based extreme pressure agent of the component (D) is the mass ppm of sulfur with respect to the mass part of the entire lubricating oil composition. Of the components (E), the content of succinimides (E1-1) and (E1-2) is% by mass in the lubricating oil composition, and (E2-1), (E2-2) and ( The amount of imide succinimide boronized in E2-3) is the mass ppm of boron with respect to the mass part of the entire lubricating oil composition. The amount of viscosity index improver, organic friction modifier and other additives is mass% based on the total mass of the composition. The amount of base oil is the balance with 100% by mass of the entire lubricating oil composition. The kinematic viscosity of the composition at 100 ° C. (measured at 100 ° C. according to ASTM D445) was expressed as ^{KV100 (mm 2 / s).} The kinematic viscosity of the composition at 40 ° C. (measured at 40 ° C. according to ASTM D445) was expressed as ^{KV40 (mm 2 / s).}

The following tests were performed on these lubricating oil compositions. The results are shown in Tables 4-6.
(1) Abrasion resistance
Measured at 40 kgf, 80 ° C., 1800 rpm, 30 minutes according to ASTM D4172.
(2) Seizure resistance
Measured according to ASTM D2783.
(3) Bearing wear The cycle until wear was measured by a cycle test.
(4) Coefficient of friction between metals (80 ° C)
It was measured at 80 ° C. using an MTM tester.
(5) Volume resistivity Measured at 80 ° C. according to JIS C2101.
(6) Ring-on test
In a ring-on-disk tester, under poor lubrication conditions, a test in which a load of 2000 N was constant and acceleration / deceleration was repeated was carried out until burning, and the number of cycles was measured. Here, the test in which acceleration / deceleration is repeated means accelerating to 1 m / sec in 5 seconds from the start of the test, maintaining 1 m / sec for 5 seconds, decelerating to 0 m / s over 5 seconds, and 0 m / sec for 5 seconds. maintain. 20 seconds was set as one cycle, and the number of cycles until burning was shown in the table. In Comparative Examples 1 to 4, the results were described as 0 because they were burned in less than 20 seconds (that is, less than one cycle).

The lubricating oil composition of the present invention have the low viscosity condition of kinematic viscosity 10 mm ² / s Ultra to 20 mm ² / s at 40 ° C., superior component protection performance, high electrical insulating properties, and the material compatibility, further Has improved seizure resistance and is highly reliable. The lubricating oil composition of the present invention is suitable as a transmission or gear oil for hybrid vehicles, electric vehicles, and fuel cell vehicles.

Claims (17)

In the lubricating oil composition containing the following components (A) to (F),
(A) Lubricating oil base oil,
(B) Metal cleaner,
(C) Phosphorus-based extreme pressure agent,
(D) Sulfur-based extreme pressure agent,
(E) Ash-free dispersant,
And (F) a viscosity index improver having a weight average molecular weight (Mw) of 10,000 to 100,000,
The (C) phosphorus-based extreme pressure agent contains one or more selected from (C1) phosphite ester and phosphonic acid ester, and (C2) acidic phosphoric acid ester having an alkyl group having 11 to 30 carbon atoms. E) The ashless dispersant is (E1) poly α-olefin-containing (poly) ethyleneamine succinate imide represented by the following formula.

(In the formula, R is a polyα-olefin residue having 20 to 1000 carbon atoms having a repeating unit derived from an α-olefin having 6 to 14 carbon atoms independently of each other, and a is an integer of 1 to 10 carbon atoms. ), And (E2) containing a boronized product of a poly-α-olefin succinimide having a weight average molecular weight (Mw) of 1500-4500.
And wherein the kinematic viscosity at 40 ° C. of the lubricating oil composition is in the range of 10 mm ² / s Ultra to 20 mm ² / s, and the boron content of the lubricating oil composition is 25 to 150 ppm by weight To do,
The lubricating oil composition. The lubricating oil composition according to claim 1, wherein the lubricating oil base oil (A) has a kinematic viscosity ^{of 1 to 4.5 mm 2 / s at 100 ° C.} The lubricating oil composition according to claim 1 or 2, wherein the metal cleaning agent (B) comprises at least one selected from calcium salicylate, calcium sulfonate, magnesium salicylate and magnesium sulfonate. The lubricating oil composition according to any one of claims 1 to 3, wherein the metal cleaning agent (B) has a total base value of 50 to 600 mgKOH / g. The invention according to any one of claims 1 to 4, wherein in (C1), the phosphite ester has an alkyl group having 4 to 30 carbon atoms and the phosphonic acid ester has an alkyl group having 4 to 30 carbon atoms. Lubricating oil composition. The lubricating oil composition according to any one of claims 1 to 5, wherein the (C2) acidic phosphoric acid ester has an alkyl group having 11 to 20 carbon atoms. The lubricating oil composition according to any one of claims 1 to 6, wherein the sulfur-based extreme pressure agent (D) is at least one selected from thiadiazole, an olefin sulfide, a sulfide oil and fat, and a sulfide ester. The lubricating oil composition according to any one of claims 1 to 7, wherein the sulfur-based extreme pressure agent (D) has an active sulfur amount of 0.5 to 15% by mass. (G) The lubricating oil composition according to any one of claims 1 to 8, further comprising an organic friction modifier. The lubrication according to claim 9, wherein the (G) organic friction modifier is at least one selected from an ester-based friction modifier, an amine-based friction modifier, an amide-based friction modifier, and an imide-based friction modifier. Oil composition. The lubricating oil composition according to any one of claims 1 to 10, further comprising (H) a chain unsaturated (di) carboxylic acid or an anhydride thereof or an alkyl ester thereof and a copolymer of a vinyl compound. The lubricating oil composition according to claim 11, wherein the component (H) is a fumaric acid alkyl ester / vinyl acetate copolymer. The lubricating oil composition according to any one of claims 1 to 12, which is used for a hybrid vehicle. The lubricating oil composition according to any one of claims 1 to 12, which is for an electric vehicle. The lubricating oil composition according to any one of claims 1 to 14, which is used for a fuel cell vehicle. The lubricating oil composition according to any one of claims 1 to 15, which is used for transmission oil. The lubricating oil composition according to any one of claims 1 to 15, which is used for gear oil.