LUBRICANT COMPOSITION FOR GEAR OIL

Abstract
The present invention relates to a lubricant composition, and more particularly to a lubricant composition, which includes an ethylene-alphaolefin oligomer and an alkylated phosphonium compound, thus realizing energy reduction and an increased endurance life, and which is thus suitable for use in gear oil. The lubricant composition of the present invention includes a base oil, a liquid olefin copolymer, and an alkylated phosphonium compound.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based on and claims priority from Korean Patent Application No. 10-2019-0023683, filed on Feb. 28, 2019 with the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference.


BACKGROUND OF THE INVENTION
1. Technical Field

The present invention relates to a lubricant composition, and more particularly to a lubricant composition, which includes an ethylene-alphaolefin oligomer and an alkylated phosphonium compound, thus realizing energy reduction and an increased endurance life, and which is thus suitable for use in gear oil.


2. Description of the Related Art

Recently, as environmental problems such as global warming, destruction of the ozone layer, etc. have come to the fore, environmental regulations have become strict. Hence, reduction of carbon dioxide emissions is receiving a great deal of attention. In order to reduce carbon dioxide emissions, it is urgent to decrease energy consumption in vehicles, construction machinery, agricultural machinery and the like, that is, to increase fuel economy, and thus there is a strong demand for measures capable of contributing to energy reduction in an engine, a transmission, a final reducer, a compressor, a hydraulic device and the like. Accordingly, lubricants used in such devices are required to have the ability to decrease stirring resistance or friction resistance compared to conventional cases.


A lubricant is an oily material used to reduce the generation of frictional force on the friction surface of a machine or to dissipate frictional heat generated from the friction surface. The lubricant is manufactured by adding additives to base oil, and is largely classified into a mineral-oil-based lubricant (petroleum-based lubricant) and a synthetic lubricant depending on the type of base oil, the synthetic lubricant being classified into a polyalphaolefin-based lubricant and an ester-based lubricant.


As means for improving fuel economy in gears of transmissions and reducers, decreasing the viscosity of a lubricant is generally used. For example, among transmissions, an automatic transmission or a continuously variable transmission for vehicles has a torque converter, a wet clutch, a gear bearing mechanism, an oil pump, a hydraulic control mechanism, etc., and a manual transmission or a reducer has a gear bearing mechanism, and thus when the viscosity of lubricant used therefor is further decreased, stirring resistance and friction resistance of the torque converter, the wet clutch, the gear bearing mechanism, and the oil pump are decreased, thereby increasing power transmission efficiency, ultimately making it possible to improve the fuel economy of vehicles.


However, when the viscosity of conventional lubricants is lowered, fitting performance is greatly decreased due to the deterioration of friction performance, and sticking or the like occurs, thus causing defects in the transmission or the like. Particularly, in the case of low viscosity, a viscosity modifier is sheared during the use thereof, and thus the viscosity is lowered, so that the wear resistance of the gear is damaged and fitting performance is easily deteriorated. Furthermore, even when a sulfur/phosphorus extreme pressure agent is added to increase the extreme pressure performance of low-viscosity oil, fitting performance and endurance life are remarkably decreased, making it difficult to realize long-term use thereof.


Therefore, the present inventors have developed a lubricant composition for gear oil, which is capable of reducing the mechanical wear of gear parts and energy consumption and also of exhibiting superior thermal stability and oxidation stability, and may thus be industrially used for a long period of time.


CITATION LIST
Patent Literature

(Patent Document 0001) Korean Patent No. 10-1420890


(Patent Document 0002) Korean Patent No. 10-1347964


SUMMARY OF THE INVENTION

Accordingly, the present invention has been made keeping in mind the problems encountered in the related art, and an objective of the present invention is to provide a lubricant composition, in which a functional additive for friction reduction and an ethylene-alphaolefin liquid random copolymer are mixed, thereby exhibiting superior friction characteristics, thermal stability and oxidation stability.


Another objective of the present invention is to provide a lubricant composition for gear oil, which is able to reduce the mechanical wear of gear parts and energy consumption when applied to gears of transmissions and reducers, and may be used for a long period of time due to low changes in the physical properties of gear oil.


In order to accomplish the above objectives, the present invention provides a lubricant composition, comprising a base oil, a liquid olefin copolymer, and an alkylated phosphonium compound.


The base oil may be at least one selected from the group consisting of mineral oil, polyalphaolefin (PAO) and ester.


The liquid olefin copolymer may be prepared by copolymerizing ethylene and alphaolefin in the presence of a single-site catalyst system, and the single-site catalyst system preferably includes a metallocene catalyst, an organometallic compound and an ionic compound.


The liquid olefin copolymer may have a coefficient of thermal expansion of 3.0 to 4.0.


In the lubricant composition of the present invention, the liquid olefin copolymer may be included in an amount of 0.1 to 30 wt %, and preferably 0.5 to 25 wt %. The alkylated phosphonium compound may be included in an amount of 0.1 to 5.0 wt %, and preferably 0.3 to 4.0 wt %.


The lubricant composition may have an SRV friction coefficient of 0.2 to 0.3 and a traction coefficient of 0.15 to 0.3. Moreover, the lubricant composition may have a pinion torque loss rate due to friction of less than 1% in an FZG gear efficiency test.


According to the present invention, a lubricant composition includes an alkylated phosphonium compound as a friction-reducing agent, in addition to an existing sulfur/phosphorus extreme pressure agent, thereby maximizing friction performance to thus reduce the mechanical wear of gear parts and energy consumption when applied to gears of transmissions and reducers, ultimately maximizing energy-saving effects.


Also, according to the present invention, the lubricant composition includes, as a viscosity modifier, an olefin copolymer prepared in the presence of a metallocene compound catalyst, and can thus exhibit a high viscosity index and superior low-temperature stability.


Therefore, the present invention can provide a lubricant composition for gear oil, which enables long-term use due to low changes in the physical properties of gear oil.







DESCRIPTION OF SPECIFIC EMBODIMENTS

Hereinafter, a detailed description will be given of the present invention.


The present invention relates to a lubricant composition, which has superior oxidation stability and friction characteristics and is thus suitable for use in gear oil. Hence, the lubricant composition of the present invention includes a base oil, a liquid olefin copolymer, and an alkylated phosphonium compound.


Here, the base oil varies from the aspects of viscosity, heat resistance, oxidation stability and the like depending on the manufacturing method or refining method, but is generally classified into mineral oil and synthetic oil. The API (American Petroleum Institute) classifies base oil into five types, namely Group I, II, III, IV and V. These types, based on API ranges, are defined in API Publication 1509, 15th Edition, Appendix E, April 2002, and are shown in Table 1 below.














TABLE 1








Saturated hydrocarbon
Sulfur
Viscosity




(%)
(%)
index









Group I
<90
>0.03
80 ≤ VI < 120



Group II
≥90
≤0.03
80 ≤ VI < 120



Group III
≥90
≤0.03
VI ≥ 120










Group IV
PAO (Poly Alpha Olefin)



Group V
Ester & Others










In the lubricant composition of the present invention, the base oil may be at least one selected from the group consisting of mineral oil, polyalphaolefin (PAO) and ester, and may be any type among Groups I to V based on the API ranges.


More specifically, mineral oil belongs to Groups I to III based on the API ranges, and mineral oil may include oil resulting from subjecting a lubricant distillate fraction, obtained through atmospheric distillation and/or vacuum distillation of crude oil, to at least one refining process of solvent deasphalting, solvent extraction, hydrogenolysis, solvent dewaxing, catalytic dewaxing, hydrorefining, sulfuric acid cleaning, and white clay treatment; wax isomerized mineral oil; or a gas-to-liquid (GLT) oil obtained via the Fischer-Tropsch process.


The synthetic oil belongs to Group IV or V based on the API ranges, and polyalphaolefin belonging to Group IV may be obtained through oligomerization of a higher alphaolefin using an acid catalyst, as disclosed in U.S. Pat. No. 3,780,128, 4,032,591, Japanese Patent Application Publication No. Hei. 1-163136, and the like, but the present invention is not limited thereto.


Examples of the synthetic oil belonging to Group V include alkyl benzenes, alkyl naphthalenes, isobutene oligomers or hydrides thereof, paraffins, polyoxy alkylene glycol, dialkyl diphenyl ether, polyphenyl ether, ester, and the like.


Here, the alkyl benzenes and alkyl naphthalenes are usually dialkylbenzene or dialkylnaphthalene having an alkyl chain length of 6 to 14 carbon atoms, and the alkyl benzenes or alkyl naphthalenes are prepared through Friedel-Crafts alkylation of benzene or naphthalene with olefin. The alkylated olefin used in the preparation of alkyl benzenes or alkyl naphthalenes may be linear or branched olefins or combinations thereof.


Also, examples of the ester include, but are not limited to, ditridecyl glutarate, di-2-ethylhexyl adipate, diisodecyl adipate, ditridecyl adipate, di-2-ethylhexyl sebacate, tridecyl pelargonate, di-2-ethylhexyl adipate, di-2-ethylhexyl azelate, trimethylolpropane caprylate, trimethylolpropane pelargonate, trimethylolpropane triheptanoate, pentaerythritol 2-ethylhexanoate, pentaerythritol pelargonate, pentaerythritol tetraheptanoate, and the like.


In the lubricant composition of the present invention, the liquid olefin copolymer is prepared by copolymerizing ethylene and alphaolefin monomers in the presence of a single-site catalyst system in order to uniformly distribute alphaolefin units in the copolymer chain. Preferably, the liquid olefin copolymer is prepared by reacting ethylene and alphaolefin monomers in the presence of a single-site catalyst system including a crosslinked metallocene compound, an organometallic compound, and an ionic compound for forming an ion pair through reaction with the crosslinked metallocene compound.


Here, the metallocene compound included in the single-site catalyst system may be at least one selected from the group consisting of Chemical Formulas 1 to 6 below.




embedded image


In Chemical Formulas 1 to 4,

    • M is a transition metal selected from the group consisting of titanium, zirconium, and hafnium,
    • B is absent or is a linking group including a C1-C20 alkylene group, a C6-C20 arylene group, C1-C20 dialkyl silicon, C1-C20 dialkyl germanium, a C1-C20 alkylphosphine group or a C1-C20 alkylamine group,
    • X1 and X2, which are the same as or different from each other, are each independently a halogen atom, a C1-C20 alkyl group, a C2-C20 alkenyl group, a C2-C20 alkynyl group, a C6-C20 aryl group, a C7-C40 alkylaryl group, a C7-C40 arylalkyl group, a C1-C20 alkylamido group, a C6-C20 arylamido group, a C1-C20 alkylidene group or a C1-C20 alkoxy group, and
    • R1 to R10, which are the same as or different from each other, are each independently hydrogen, a C1-C20 alkyl group, a C2-C20 alkenyl group, a C6-C20 aryl group, a C7-C20 alkylaryl group, a C7-C20 arylalkyl group, a C5-C60 cycloalkyl group, a C4-C20 heterocyclic group, a C1-C20 alkynyl group, a C6-C20-aryl-containing hetero group or a silyl group.




embedded image


In Chemical Formulas 5 and 6,

    • M is a transition metal selected from the group consisting of titanium, zirconium, and hafnium,
    • B is absent or is a linking group including a C1-C20 alkylene group, a C6-C20 arylene group, a C1-C20 dialkyl silicon, a C1-C20 dialkyl germanium, a C1-C20 alkylphosphine group or a C1-C20 alkylamine group,
    • X1 and X2, which are the same as or different from each other, are each independently a halogen atom, a C1-C20 alkyl group, a C2-C20 alkenyl group, a C2-C20 alkynyl group, a C6-C20 aryl group, a C7-C40 alkylaryl group, a C7-C40 arylalkyl group, a C1-C20 alkylamido group, a C6-C20 arylamido group, a C1-C20 alkylidene group or a C1-C20 alkoxy group, and
    • R1 to R10, which are the same as or different from each other, are each independently hydrogen, a C1-C20 alkyl group, a C2-C20 alkenyl group, a C6-C20 aryl group, a C7-C20 alkylaryl group, a C7-C20 arylalkyl group, a C5-C60 cycloalkyl group, a C4-C20 heterocyclic group, a C1-C20 alkynyl group, a C6-C20-aryl-containing hetero group or a silyl group.


Furthermore, all of R11, R13 and R14 are hydrogen, and each of R12 radicals, which are the same as or different from each other, may independently be hydrogen, a C1-C20 alkyl group, a C2-C20 alkenyl group, a C6-C20 aryl group, a C7-C20 alkylaryl group, a C7-C20 arylalkyl group, a C5-C60 cycloalkyl group, a C4-C20 heterocyclic group, a C1-C20 alkynyl group, a C6-C20-aryl-containing hetero group or a silyl group.


Also, the metallocene compound of Chemical Formulas 2 to 6 may include a compound substituted through a hydroaddition reaction, and a preferred example thereof includes dimethylsilyl bis(tetrahydroindenyl) zirconium dichloride.


The organometallic compound included in the single-site catalyst system may be at least one selected from the group consisting of an organoaluminum compound, an organomagnesium compound, an organozinc compound and an organolithium compound, and is preferably an organoaluminum compound. The organoaluminum compound may be at least one selected from the group consisting of, for example, trimethylaluminum, triethylaluminum, triisobutylaluminum, tripropylaluminum, tributylaluminum, dimethylchloroaluminum, dimethylisobutylaluminum, dimethylethylaluminum, diethylchloroaluminum, triisopropylaluminum, triisobutylaluminum, tricyclopentylaluminum, tripentylaluminum, triisopentylaluminum, ethyldimethylaluminum, methyldiethylaluminum, triphenylaluminum, methylaluminoxane, ethylaluminoxane, isobutylaluminoxane and butylaluminoxane, and is preferably triisobutylaluminum.


The ionic compound included in the single-site catalyst system may be at least one selected from the group consisting of organoboron compounds such as dimethylanilinium tetrakis(perfluorophenyl)borate, triphenylcarbenium tetrakis(perfluorophenyl)borate, and the like.


The component ratio of the single-site catalyst system may be determined in consideration of catalytic activity, and the molar ratio of metallocene catalyst:ionic compound:organometallic compound is preferably adjusted in the range of 1:1:5 to 1:10:1000 in order to ensure desired catalytic activity.


Furthermore, the components of the single-site catalyst system may be added at the same time or in any sequence to an appropriate solvent and may thus function as an active catalyst system. Here, the solvent may include, but is not limited to, a hydrocarbon solvent such as pentane, hexane, heptane, etc., or an aromatic solvent such as benzene, toluene, xylene, etc., and any solvent usable in the preparation may be used.


Also, the alphaolefin monomer used in the preparation of the liquid olefin copolymer includes a C2-C20 aliphatic olefin, and may specifically be at least one selected from the group consisting of ethylene, propylene, 1-butene, 1-pentene, 3-methyl-1-butene, 1-hexene, 4-methyl-1-pentene, 3-methyl-1-pentene, 1-heptene, 1-octene, 1-decene, 1-dodecene and 1-tetradecene, and may include isomeric forms, but the present invention is not limited thereto. In the copolymerization, the monomer content is 1 to 95 mol %, preferably 5 to 90 mol %.


The liquid olefin copolymer required in the present invention has a coefficient of thermal expansion of 3.0 to 4.0 and a bromine number of 0.1 or less.


The liquid olefin copolymer may be included in an amount of 0.1 to 30 wt %, and preferably 0.5 to 25 wt %, based on 100 wt % of the lubricant composition. If the amount of the liquid olefin copolymer is less than 0.1 wt % based on 100 wt % of the lubricant composition, low-temperature stability may deteriorate. On the other hand, if the amount thereof exceeds 30 wt %, sufficient viscosity cannot be realized, and thus application of the resulting composition to gear oil becomes difficult, which is undesirable.


The alkylated phosphonium compound, serving as a friction-reducing agent, may be at least one selected from the group consisting of tetraoctylated phosphonium bisethylhexyl phosphate, tributyltetradecylphosphonium bis(2-ethylhexyl)phosphate, tetraethylphosphonium bis(2-ethylhexyl)phosphate and tributylphosphonium bis(2-ethylhexly)phosphate. When the alkylated phosphonium compound is included in the lubricant composition, it may exhibit synergistic effects with an existing wear-resistant agent and friction reduction effects, and additionally, energy-saving effects may be achieved through friction reduction.


The alkylated phosphonium compound may be included in an amount of 0.1 to 5.0 wt %, and preferably 0.3 to 4.0 wt %, based on 100 wt % of the lubricant composition. If the amount of the alkylated phosphonium compound is less than 0.1 wt % based on 100 wt % of the lubricant composition, the friction reduction effect is insignificant. On the other hand, if the amount thereof exceeds 5.0 wt %, the additional reduction effect is insignificant despite the excessive addition thereof, which is undesirable.


The lubricant composition of the present invention may further include an additive selected from the group consisting of an antioxidant, a metal cleaner, an anticorrosive agent, a foam inhibitor, a pour-point depressant, a viscosity modifier, a wear-resistant agent and combinations thereof.


The antioxidant may be included in an amount of 0.01 to 5.0 wt % based on 100 wt % of the lubricant composition, and is preferably used in the form of a mixture of a phenolic antioxidant and an aminic antioxidant, more preferably a mixture of 0.01 to 3.0 wt % of the phenolic antioxidant and 0.01 to 3.0 wt % of the aminic antioxidant.


The phenolic antioxidant may be any one selected from the group consisting of 2,6-dibutylphenol, hindered bisphenol, high-molecular-weight hindered phenol, and hindered phenol with thioether.


The aminic antioxidant may be any one selected from the group consisting of diphenylamine, alkylated diphenylamine and naphthylamine, and preferably, the alkylated diphenylamine is dioctyldiphenylamine, octylated diphenylamine, or butylated diphenylamine.


The metal cleaner may be at least one selected from the group consisting of metallic phenate, metallic sulfonate, and metallic salicylate, and preferably, the metal cleaner is included in an amount of 0.1 to 10.0 wt % based on 100 wt % of the lubricant composition.


The anticorrosive agent may be a benzotriazole derivative, and is preferably any one selected from the group consisting of benzotriazole, 2-methylbenzotriazole, 2-phenylbenzotriazole, 2-ethylbenzotriazole and 2-propylbenzotriazole. The anticorrosive agent may be included in an amount of 0 to 4.0 wt % based on 100 wt % of the lubricant composition.


The foam inhibitor may be polyoxyalkylene polyol, and preferably, the foam inhibitor is included in an amount of 0 to 4.0 wt % based on 100 wt % of the lubricant composition.


The pour-point depressant may be poly(methyl methacrylate), and preferably, the pour-point depressant is included in an amount of 0.01 to 5.0 wt % based on 100 wt % of the lubricant composition.


The viscosity modifier may be polyisobutylene or polymethacrylate, and preferably, the viscosity modifier is included in an amount of 0 to 15 wt % based on 100 wt % of the lubricant composition.


The wear-resistant agent may be at least one selected from the group consisting of organic borates, organic phosphites, organic sulfur-containing compounds, zinc dialkyl dithiophosphate, zinc diaryl dithiophosphate and phosphosulfurized hydrocarbon, and preferably, the wear-resistant agent is included in an amount of 0.01 to 3.0 wt %.


The lubricant composition of the present invention has an SRV friction coefficient of 0.2 to 0.3 and a traction coefficient of 0.15 to 0.3. Also, the lubricant composition of the present invention has a pinion torque loss rate due to friction of less than 1%, as measured through an FZG gear efficiency test as a gear oil rig test.


A better understanding of the present invention through the following examples. However, the present invention is not limited to these examples, but may be embodied in other forms. These examples are provided to thoroughly explain the invention and to sufficiently transfer the spirit of the present invention to those skilled in the art.


1. Preparation of Additive Composition


An additive composition for use in the lubricant composition of the present invention was prepared as shown in Table 2 below.











TABLE 2






Composition
Composition


Additive composition
A
B


















Antioxidant
2,6-dibutylphenol
1
1.5



Diphenylamine
0.8
1


Metal cleaner
Metallic phenate
0.2
0.6


Anticorrosive
Benzotriazole
0.3
1.0


agent





Foam inhibitor
Polyoxyalkylene polyol
0.01
0.02


Pour-point
Polymethylmethacrylate
0.2
0.5


depressant





Viscosity
Polyisobutylene
1.0



modifier





Wear-resistant
Zinc diaryl
0.2
1.1


agent
dithiophosphate









2. Liquid Olefin Copolymer


A liquid olefin copolymer was prepared using an oligomerization method through a catalytic reaction process. Depending on the reaction time and conditions, which follow, liquid olefin copolymers having different molecular weights were prepared, and the properties thereof are shown in Table 3 below.


The reaction time and conditions were increased by 4 hr each from 20 hr. Here, the amounts of hydrogen and comonomer C3, which were added thereto, were increased by 10% each, and polymerization was performed under individual conditions, and the resulting polymers were classified depending on the molecular weight thereof.










TABLE 3








Main properties










Alphaolefin
Evaporation
Thickening Power
CoE of


copolymer
Loss (%)
(10 wt % in 150N)
Thermal Expansion













Copolymer I
1.28
6
3.00 to 3.20


Copolymer II
0.54
7
3.20 to 3.40


Copolymer III
0.10
8
3.40 to 3.50


Copolymer IV
0.001
10
3.50 to 3.60


Copolymer V
0.0001
12
3.60 to 3.70


Copolymer VI
0.00001
14
3.70 to 3.80









3. Preparation of Lubricant Composition For Gear Oil


A lubricant composition was prepared by mixing a base oil, the liquid olefin copolymer, an alkylated phosphonium compound, and the additive prepared above, as shown in Tables 4 and 5 below. Here, the base oil was polyalphaolefin (PAO 4 cSt, available from Chevron Philips) having kinematic viscosity of 4 cSt at 100° C., and the alkylated phosphonium compound was tetraoctylated phosphonium bisethylhexyl phosphate.


Preparation Examples 1 to 72 and Comparative Examples 1 to 9. Lubricant Composition For Gear Oil Including Additive A













TABLE 4






Base
Alphaolefin
Alkylated phosphonium
Additive


Composition
oil
copolymer
compound
A



















Preparation
97.14
Copolymer I
0.1
2.71


Example 1

0.05




Preparation
96.74
Copolymer I
0.5
2.71


Example 2

0.05




Preparation
96.24
Copolymer I
1.0
2.71


Example 3

0.05




Preparation
94.24
Copolymer I
3.0
2.71


Example 4

0.05




Preparation
92.24
Copolymer I
5.0
2.71


Example 5

0.05




Preparation
95.79
Copolymer I
1.0
2.71


Example 6

0.5




Preparation
93.79
Copolymer I
3.0
2.71


Example 7

0.5




Preparation
91.79
Copolymer I 5
0.5
2.71


Example 8






Preparation
89.29
Copolymer I 5
3.0
2.71


Example 9






Preparation
87.29
Copolymer I 5
5.0
2.71


Example 10






Preparation
86.79
Copolymer I 10
0.5
2.71


Example 11






Preparation
86.29
Copolymer I 10
1.0
2.71


Example 12






Preparation
82.29
Copolymer I 10
5.0
2.71


Example 13






Preparation
76.79
Copolymer I 20
0.5
2.71


Example 14






Preparation
72.29
Copolymer I 20
5.0
2.71


Example 15






Preparation
67.19
Copolymer I 30
0.1
2.71


Example 16






Preparation
62.29
Copolymer I 30
5.0
2.71


Example 17






Preparation
61.79
Copolymer I 35
0.5
2.71


Example 18






Preparation
61.29
Copolymer I 35
1.0
2.71


Example 19






Preparation
59.29
Copolymer I 35
3.0
2.71


Example 20






Preparation
57.29
Copolymer I 35
5.0
2.71


Example 21






Preparation
52.29
Copolymer I 35
10.0
2.71


Example 22






Preparation
97.14
Copolymer II
0.1
2.71


Example 23

0.05




Preparation
96.74
Copolymer II
0.5
2.71


Example 24

0.05




Preparation
96.24
Copolymer II
1.0
2.71


Example 25

0.05




Preparation
94.24
Copolymer II
3.0
2.71


Example 26

0.05




Preparation
92.24
Copolymer II
5.0
2.71


Example 27

0.05




Preparation
95.79
Copolymer II
1.0
2.71


Example 28

0.5




Preparation
93.79
Copolymer II
3.0
2.71


Example 29

0.5




Preparation
91.79
Copolymer II 5
0.5
2.71


Example 30






Preparation
91.29
Copolymer II 5
1.0
2.71


Example 31






Preparation
87.29
Copolymer II 5
5.0
2.71


Example 32






Preparation
87.19
Copolymer II
0.1
2.71


Example 33

10




Preparation
86.29
Copolymer II
1.0
2.71


Example 34

10




Preparation
84.29
Copolymer II
3.0
2.71


Example 35

10




Preparation
82.29
Copolymer II
5.0
2.71


Example 36

10




Preparation
77.19
Copolymer II
0.1
2.71


Example 37

20




Preparation
74.29
Copolymer II
3.0
2.71


Example 38

20




Preparation
72.29
Copolymer II
5.0
2.71


Example 39

20




Preparation
67.19
Copolymer II
0.1
2.71


Example 40

30




Preparation
97.14
Copolymer III
0.1
2.71


Example 41

0.05




Preparation
96.74
Copolymer III
0.5
2.71


Example 42

0.05




Preparation
96.24
Copolymer III
1.0
2.71


Example 43

0.05




Preparation
94.24
Copolymer III
3.0
2.71


Example 44

0.05




Preparation
91.79
Copolymer III
0.5
2.71


Example 45

5




Preparation
87.29
Copolymer III
5.0
2.71


Example 46

5




Preparation
86.79
Copolymer III
0.5
2.71


Example 47

10




Preparation
82.29
Copolymer III
5.0
2.71


Example 48

10




Preparation
76.79
Copolymer III
0.5
2.71


Example 49

20




Preparation
76.29
Copolymer III
1.0
2.71


Example 50

20




Preparation
72.29
Copolymer III
5.0
2.71


Example 51

20




Preparation
92.19
Copolymer IV 5
0.1
2.71


Example 52






Preparation
89.29
Copolymer IV 5
3.0
2.71


Example 53






Preparation
87.29
Copolymer IV 5
5.0
2.71


Example 54






Preparation
82.29
Copolymer IV 5
10.0
2.71


Example 55






Preparation
86.79
Copolymer IV
0.5
2.71


Example 56

10




Preparation
74.29
Copolymer IV
3.0
2.71


Example 57

20




Preparation
76.79
Copolymer IV
0.5
2.71


Example 58

20




Preparation
91.79
Copolymer V 5
0.5
2.71


Example 59






Preparation
86.79
Copolymer V 10
0.5
2.71


Example 60






Preparation
82.29
Copolymer V 10
5.0
2.71


Example 61






Preparation
77.19
Copolymer V 20
0.1
2.71


Example 62






Preparation
76.79
Copolymer V 20
0.5
2.71


Example 63






Preparation
72.29
Copolymer V 20
5.0
2.71


Example 64






Preparation
67.19
Copolymer V 30
0.1
2.71


Example 65






Preparation
66.79
Copolymer V 30
0.5
2.71


Example 66






Preparation
97.14
Copolymer VI
0.1
2.71


Example 67

0.05




Preparation
96.74
Copolymer VI
0.5
2.71


Example 68

0.05




Preparation
96.24
Copolymer VI
1.0
2.71


Example 69

0.05




Preparation
91.79
Copolymer VI 5
0.5
2.71


Example 70






Preparation
86.79
Copolymer VI
0.5
2.71


Example 71

10




Preparation
76.79
Copolymer VI
0.5
2.71


Example 72

20




Comparative
97.24
Copolymer I

2.71


Example 1

0.05




Comparative
97.24
Copolymer II

2.71


Example 2

0.05




Comparative
87.29
Copolymer II

2.71


Example 3

10




Comparative
77.29
Copolymer II

2.71


Example 4

20




Comparative
67.29
Copolymer II

2.71


Example 5

30




Comparative
92.29
Copolymer IV 5

2.71


Example 6






Comparative
67.29
Copolymer V 30

2.71


Example 7






Comparative
62.29
Copolymer V 35

2.71


Example 8






Comparative
97.24
Copolymer VI

2.71


Example 9

0.05











Preparation Examples 73 to 148 and Comparative Examples to 16. Lubricant Composition For Gear Oil Including Additive B













TABLE 5






Base
Alphaolefin
Alkylated phosphonium
Additive


Composition
oil
copolymer
compound
B



















Preparation
92.28
Copolymer I
0.5
6.72


Example 73

0.5




Preparation
91.78
Copolymer I
1.0
6.72


Example 74

0.5




Preparation
87.78
Copolymer I 5
0.5
6.72


Example 75






Preparation
87.28
Copolymer I 5
1.0
6.72


Example 76






Preparation
82.28
Copolymer I
1.0
6.72


Example 77

10




Preparation
80.28
Copolymer I
3.0
6.72


Example 78

10




Preparation
72.78
Copolymer I
0.5
6.72


Example 79

20




Preparation
72.28
Copolymer I
1.0
6.72


Example 80

20




Preparation
91.78
Copolymer II
1.0
6.72


Example 81

0.5




Preparation
89.78
Copolymer II
3.0
6.72


Example 82

0.5




Preparation
87.78
Copolymer II
0.5
6.72


Example 83

5




Preparation
87.28
Copolymer II
1.0
6.72


Example 84

5




Preparation
82.28
Copolymer II
1.0
6.72


Example 85

10




Preparation
80.28
Copolymer II
3.0
6.72


Example 86

10




Preparation
70.28
Copolymer II
3.0
6.72


Example 87

20




Preparation
62.78
Copolymer II
0.5
6.72


Example 88

30




Preparation
62.28
Copolymer II
1.0
6.72


Example 89

30




Preparation
60.28
Copolymer II
3.0
6.72


Example 90

30




Preparation
58.28
Copolymer II
5.0
6.72


Example 91

30




Preparation
93.13
Copolymer III
0.1
6.72


Example 91

0.05




Preparation
92.73
Copolymer III
0.5
6.72


Example 93

0.05




Preparation
92.23
Copolymer III
1.0
6.72


Example 94

0.05




Preparation
90.23
Copolymer III
3.0
6.72


Example 95

0.05




Preparation
87.78
Copolymer III
0.5
6.72


Example 96

5




Preparation
83.28
Copolymer III
5.0
6.72


Example 97

5




Preparation
82.78
Copolymer III
0.5
6.72


Example 98

10




Preparation
78.28
Copolymer III
5.0
6.72


Example 99

10




Preparation
72.78
Copolymer III
0.5
6.72


Example 100

20




Preparation
72.28
Copolymer III
1.0
6.72


Example 101

20




Preparation
68.28
Copolymer III
5.0
6.72


Example 102

20




Preparation
58.28
Copolymer III
5.0
6.72


Example 103

30




Preparation
58.18
Copolymer III
0.1
6.72


Example 104

35




Preparation
57.78
Copolymer III
0.5
6.72


Example 105

35




Preparation
57.28
Copolymer III
1.0
6.72


Example 106

35




Preparation
55.28
Copolymer III
3.0
6.72


Example 107

35




Preparation
93.13
Copolymer IV
0.1
6.72


Example 108

0.05




Preparation
92.73
Copolymer IV
0.5
6.72


Example 109

0.05




Preparation
92.23
Copolymer IV
1.0
6.72


Example 110

0.05




Preparation
90.23
Copolymer IV
3.0
6.72


Example 111

0.05




Preparation
88.23
Copolymer IV
5.0
6.72


Example 112

0.05




Preparation
88.18
Copolymer IV
0.1
6.72


Example 113

5




Preparation
85.28
Copolymer IV
3.0
6.72


Example 114

5




Preparation
83.28
Copolymer IV
5.0
6.72


Example 115

5




Preparation
78.28
Copolymer IV
10.0
6.72


Example 116

5




Preparation
83.18
Copolymer IV
0.1
6.72


Example 117

10




Preparation
82.78
Copolymer IV
0.5
6.72


Example 118

10




Preparation
78.28
Copolymer IV
5.0
6.72


Example 119

10




Preparation
73.18
Copolymer IV
0.1
6.72


Example 120

20




Preparation
72.78
Copolymer IV
0.5
6.72


Example 121

20




Preparation
70.28
Copolymer IV
3.0
6.72


Example 122

20




Preparation
93.13
Copolymer V
0.1
6.72


Example 123

0.05




Preparation
92.73
Copolymer V
0.5
6.72


Example 124

0.05




Preparation
92.23
Copolymer V
1.0
6.72


Example 125

0.05




Preparation
90.23
Copolymer V
3.0
6.72


Example 126

0.05




Preparation
88.23
Copolymer V
5.0
6.72


Example 127

0.05




Preparation
88.18
Copolymer V 5
0.1
6.72


Example 128






Preparation
87.78
Copolymer V 5
0.5
6.72


Example 129






Preparation
83.28
Copolymer V 5
5.0
6.72


Example 130






Preparation
82.78
Copolymer V
0.5
6.72


Example 131

10




Preparation
78.28
Copolymer V
5.0
6.72


Example 132

10




Preparation
72.78
Copolymer V
0.5
6.72


Example 133

20




Preparation
72.28
Copolymer V
1.0
6.72


Example 134

20




Preparation
63.18
Copolymer V
0.1
6.72


Example 135

30




Preparation
90.23
Copolymer VI
3.0
6.72


Example 136

0.05




Preparation
88.23
Copolymer VI
5.0
6.72


Example 137

0.05




Preparation
87.78
Copolymer VI
0.5
6.72


Example 138

5




Preparation
85.28
Copolymer VI
3.0
6.72


Example 139

5




Preparation
83.18
Copolymer VI
0.1
6.72


Example 140

10




Preparation
82.28
Copolymer VI
1.0
6.72


Example 141

10




Preparation
78.28
Copolymer VI
5.0
6.72


Example 142

10




Preparation
70.28
Copolymer VI
3.0
6.72


Example 143

20




Preparation
58.18
Copolymer VI
0.1
6.72


Example 144

35




Preparation
57.78
Copolymer VI
0.5
6.72


Example 145

35




Preparation
57.28
Copolymer VI
1.0
6.72


Example 146

35




Preparation
55.28
Copolymer VI
3.0
6.72


Example 147

35




Preparation
53.28
Copolymer VI
5.0
6.72


Example 148

35




Comparative
93.23
Copolymer IV

6.72


Example 10

0.05




Comparative
88.28
Copolymer IV

6.72


Example 11

5




Comparative
83.28
Copolymer IV

6.72


Example 12

10




Comparative
88.28
Copolymer V 5

6.72


Example 13






Comparative
73.28
Copolymer V

6.72


Example 14

20




Comparative
63.28
Copolymer V




Example 15

30

6.72


Comparative
88.28
Copolymer VI




Example 16

5

6.72









4. Evaluation of Properties


The properties of the lubricant compositions prepared in Preparation Examples and Comparative Examples were measured as follows. The results are shown in Tables 6 and 7 below.


Friction Coefficient


In the ball-on-disc mode, friction performance was evaluated by sequentially elevating the temperature in increments of 100□ from 40 to 120□ at 50 Hz and comparing the average friction coefficients at individual temperatures. Here, the friction coefficient value decreases with an increase in effectiveness.


Traction Coefficient


The traction coefficient was measured using an MTM instrument made by PCS Instruments. Here, the measurement conditions were fixed at 50N and SRR 50%, and friction and traction were observed depending on changes in temperature. The temperature was varied from 40 to 120□, and the average values were compared.


Wear Resistance


Four steel balls were subjected to friction with the lubricant composition for 60 min under conditions of 20 kg load, 1200 rpm, and 54□, the sizes of wear scars were compared, and evaluation was carried out in accordance with ASTM D4172. Here, the wear scar (average wear scar diameter, μm) value decreases with an increase in effectiveness.


Oxidation Stability


Oxidation stability was measured using an RBOT (Rotational Bomb Oxidation Test) meter in accordance with ASTM D2271.


Friction Loss


As a gear oil rig test, an FZG gear efficiency test was performed. In the FZG efficiency test, the pinion torque was measured through rotation with a motor drive specified depending on the type of oil under conditions in which the temperature of oil was fixed to 100° C. and no load was applied, and thus the pinion torque loss rates of existing oil and the oil using the alphaolefin copolymer and the alkylated phosphonium compound were calculated, and relative values thereof were compared.














TABLE 6










Relative





4

loss



SRV
MTM
Ball

(FZG



Friction
Traction
Wear
Oxidation
efficiency



Coefficient
Coefficient
(μm)
stability
at 100° C.)




















Preparation
0.701
0.598
496
610
1.20


Example 1







Preparation
0.732
0.569
477
654
1.09


Example 2







Preparation
0.734
0.587
432
523
1.16


Example 3







Preparation
0.735
0.544
501
320
1.30


Example 4







Preparation
0.712
0.523
665
249
1.30


Example 5







Preparation
0.285
0.200
152
1650
0.91


Example 6







Preparation
0.265
0.236
133
1600
0.90


Example 7







Preparation
0.267
0.211
110
2000
0.95


Example 8







Preparation
0.240
0.236
106
2110
0.94


Example 9







Preparation
0.736
0.569
511
333
1.15


Example 10







Preparation
0.239
0.207
123
1840
0.91


Example 11







Preparation
0.257
0.217
140
1680
0.92


Example 12







Preparation
0.745
0.564
522
285
1.22


Example 13







Preparation
0.259
0.243
147
1510
0.93


Example 14







Preparation
0.754
0.555
536
278
1.20


Example 15







Preparation
0.710
0.621
588
299
1.18


Example 16







Preparation
0.768
0.561
555
269
1.18


Example 17







Preparation
0.769
0.532
622
298
1.16


Example 18







Preparation
0.774
0.512
654
277
1.09


Example 19







Preparation
0.744
0.533
635
279
1.16


Example 20







Preparation
0.730
0.612
598
311
1.14


Example 21







Preparation
0.741
0.633
590
312
1.16


Example 22







Preparation
0.76
0.685
518
384
1.20


Example 23







Preparation
0.769
0.696
523
368
1.18


Example 24







Preparation
0.778
0.641
537
321
1.14


Example 25







Preparation
0.792
0.621
556
325
1.16


Example 26







Preparation
0.791
0.632
631
387
1.12


Example 27







Preparation
0.278
0.236
107
1610
0.93


Example 28







Preparation
0.279
0.245
108
1440
0.91


Example 29







Preparation
0.284
0.278
121
2130
0.92


Example 30







Preparation
0.291
0.247
122
2410
0.93


Example 31







Preparation
0.793
0.612
623
345
1.19


Example 32







Preparation
0.777
0.548
505
269
1.16


Example 33







Preparation
0.269
0.219
158
1780
0.95


Example 34







Preparation
0.264
0.209
169
1790
0.93


Example 35







Preparation
0.797
0.587
647
388
1.20


Example 36







Preparation
0.81
0.521
644
415
1.14


Example 37







Preparation
0.258
0.221
152
1540
0.92


Example 38







Preparation
0.755
0.555
612
321
1.30


Example 39







Preparation
0.841
0.623
698
610
1.15


Example 40







Preparation
0.702
0.665
678
654
1.14


Example 41







Preparation
0.682
0.610
598
523
1.16


Example 42







Preparation
0.713
0.587
599
320
1.30


Example 43







Preparation
0.715
0.588
587
333
1.15


Example 44







Preparation
0.258
0.211
175
2020
0.95


Example 45







Preparation
0.716
0.521
499
285
1.22


Example 46







Preparation
0.269
0.207
154
1650
0.92


Example 47







Preparation
0.717
0.569
580
278
1.20


Example 48







Preparation
0.278
0.217
135
1580
0.92


Example 49







Preparation
0.279
0.213
108
1490
0.93


Example 50







Preparation
0.726
0.587
590
269
1.18


Example 51







Preparation
0.693
0.587
520
495
1.15


Example 52







Preparation
0.231
0.247
163
2456
0.94


Example 53







Preparation
0.691
0.587
651
419
1.14


Example 54







Preparation
0.711
0.547
587
322
1.12


Example 55







Preparation
0.268
0.236
199
1680
0.91


Example 56







Preparation
0.264
0.248
185
2020
0.92


Example 57







Preparation
0.247
0.278
169
2122
0.93


Example 58







Preparation
0.254
0.219
165
1681
0.93


Example 59







Preparation
0.260
0.217
155
1519
0.92


Example 60







Preparation
0.678
0.512
655
279
1.16


Example 61







Preparation
0.621
0.547
591
325
1.18


Example 62







Preparation
0.278
0.243
123
1440
0.93


Example 63







Preparation
0.744
0.587
478
347
1.16


Example 64







Preparation
0.685
0.611
664
269
1.18


Example 65







Preparation
0.655
0.587
673
396
1.16


Example 66







Preparation
0.745
0.587
599
348
1.16


Example 67







Preparation
0.725
0.555
568
384
1.30


Example 68







Preparation
0.756
0.548
534
368
1.15


Example 69







Preparation
0.291
0.245
149
1810
0.91


Example 70







Preparation
0.269
0.278
107
1790
0.92


Example 71







Preparation
0.284
0.256
110
1540
0.94


Example 72







Comparative
0.721
0.589
454
510
1.11


Example 1







Comparative
0.759
0.674
505
348
1.22


Example 2







Comparative
0.775
0.555
436
258
1.30


Example 3







Comparative
0.811
0.588
698
412
1.18


Example 4







Comparative
0.766
0.672
664
510
1.16


Example 5







Comparative
0.725
0.611
510
465
1.30


Example 6







Comparative
0.68
0.563
636
249
1.30


Example 7







Comparative
0.7
0.587
597
321
1.20


Example 8







Comparative
0.716
0.539
498
396
1.30


Example 9





















TABLE 7










Relative





4

loss



SRV
MTM
Ball

(FZG



Friction
Traction
Wear
Oxidation
efficiency



Coefficient
Coefficient
(μm)
stability
at 100□)




















Preparation
0.268
0.209
122
1640
0.93


Example 73







Preparation
0.269
0.236
132
1490
0.91


Example 74







Preparation
0.247
0.200
164
2110
0.92


Example 75







Preparation
0.231
0.236
176
2030
0.93


Example 76







Preparation
0.254
0.211
161
1580
0.95


Example 77







Preparation
0.251
0.236
196
1490
0.94


Example 78







Preparation
0.269
0.207
193
1480
0.91


Example 79







Preparation
0.278
0.222
190
1650
0.92


Example 80







Preparation
0.277
0.236
167
1480
0.93


Example 81







Preparation
0.284
0.245
189
2020
0.94


Example 82







Preparation
0.268
0.278
107
2456
0.93


Example 83







Preparation
0.269
0.247
108
1854
0.91


Example 84







Preparation
0.284
0.219
121
1440
0.92


Example 85







Preparation
0.291
0.209
122
2080
0.93


Example 86







Preparation
0.264
0.200
169
1810
0.93


Example 87







Preparation
0.749
0.555
520
298
1.12


Example 88







Preparation
0.748
0.569
555
277
1.19


Example 89







Preparation
0.75
0.539
562
279
1.16


Example 90







Preparation
0.755
0.587
458
249
1.30


Example 91







Preparation
0.798
0.639
655
346
1.16


Example 91







Preparation
0.768
0.589
636
347
1.30


Example 93







Preparation
0.736
0.598
664
258
1.15


Example 94







Preparation
0.747
0.569
673
269
1.22


Example 95







Preparation
0.254
0.236
194
1540
0.93


Example 96







Preparation
0.822
0.587
676
287
1.20


Example 97







Preparation
0.260
0.207
123
1640
0.95


Example 98







Preparation
0.813
0.544
618
288
1.18


Example 99







Preparation
0.269
0.222
140
1490
0.93


Example 100







Preparation
0.278
0.219
146
2020
0.91


Example 101







Preparation
0.702
0.569
589
299
1.14


Example 102







Preparation
0.682
0.564
597
388
1.12


Example 103







Preparation
0.726
0.512
478
347
1.22


Example 104







Preparation
0.735
0.533
436
321
1.20


Example 105







Preparation
0.749
0.523
505
247
1.18


Example 106







Preparation
0.748
0.532
518
258
1.14


Example 107







Preparation
0.693
0.548
587
322
1.30


Example 108







Preparation
0.704
0.512
541
368
1.15


Example 109







Preparation
0.779
0.563
523
388
1.22


Example 110







Preparation
0.77
0.611
498
396
1.20


Example 111







Preparation
0.691
0.587
599
348
1.18


Example 112







Preparation
0.722
0.521
534
368
1.12


Example 113







Preparation
0.284
0.209
198
1650
0.92


Example 114







Preparation
0.715
0.555
612
345
1.15


Example 115







Preparation
0.716
0.672
647
346
1.13


Example 116







Preparation
0.726
0.498
644
258
1.30


Example 117







Preparation
0.291
0.278
107
1580
0.94


Example 118







Preparation
0.745
0.623
612
299
1.18


Example 119







Preparation
0.725
0.665
664
388
1.14


Example 120







Preparation
0.264
0.219
121
1480
0.91


Example 121







Preparation
0.269
0.256
110
1910
0.93


Example 122







Preparation
0.758
0.600
678
415
1.19


Example 123







Preparation
0.759
0.588
598
369
1.16


Example 124







Preparation
0.76
0.541
599
358
1.30


Example 125







Preparation
0.769
0.563
587
347
1.16


Example 126







Preparation
0.778
0.522
499
321
1.30


Example 127







Preparation
0.716
0.563
789
317
1.20


Example 128







Preparation
0.268
0.221
158
1480
0.93


Example 129







Preparation
0.713
0.532
580
365
1.15


Example 130







Preparation
0.264
0.236
174
2122
0.95


Example 131







Preparation
0.645
0.555
589
285
1.22


Example 132







Preparation
0.247
0.219
152
2456
0.93


Example 133







Preparation
0.231
0.211
169
1854
0.91


Example 134







Preparation
0.735
0.547
510
250
1.14


Example 135







Preparation
0.758
0.512
578
321
1.22


Example 136







Preparation
0.759
0.563
579
325
1.20


Example 137







Preparation
0.251
0.207
154
2080
0.93


Example 138







Preparation
0.260
0.234
169
2130
0.94


Example 139







Preparation
0.798
0.578
485
287
1.22


Example 140







Preparation
0.259
0.209
220
1810
0.93


Example 141







Preparation
0.822
0.601
444
412
1.12


Example 142







Preparation
0.261
0.226
226
1780
0.91


Example 143







Preparation
0.769
0.587
584
345
1.14


Example 144







Preparation
0.778
0.588
562
346
1.12


Example 145







Preparation
0.792
0.541
532
347
1.19


Example 146







Preparation
0.791
0.513
521
258
1.16


Example 147







Preparation
0.793
0.555
511
269
1.30


Example 148







Comparative
0.725
0.555
651
269
1.16


Example 10







Comparative
0.711
0.588
568
384
1.14


Example 11







Comparative
0.717
0.499
698
347
1.16


Example 12







Comparative
0.715
0.543
590
399
1.22


Example 13







Comparative
0.749
0.555
587
321
1.19


Example 14







Comparative
0.646
0.569
523
278
1.20


Example 15







Comparative
0.76
0.611
624
387
1.18


Example 16









As is apparent from Tables 6 and 7, the lubricant compositions including the liquid olefin copolymer and the alkylated phosphonium compound within the amount ranges of the present invention were significantly reduced in wear scar and friction coefficient compared to the lubricant compositions of Comparative Examples, and also exhibited superior oxidation stability.


Moreover, an efficiency improvement of at least 5 to 12% in the FZG gear efficiency test resulted, indicating that, even in practical use, the lubricant composition of the present invention was capable of reducing gear loss, thereby significantly improving fuel economy or energy-saving effects.


Therefore, it is concluded that the lubricant composition of the present invention is improved from the aspects of friction characteristics and stability and thus is suitable for use in gear oil.


Although the embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.

Claims
  • 1. A lubricant composition, comprising: a base oil, a liquid olefin copolymer, and an alkylated phosphonium compound.
  • 2. The lubricant composition of claim 1, wherein the liquid olefin copolymer is prepared by copolymerizing ethylene and alphaolefin using a single-site catalyst system.
  • 3. The lubricant composition of claim 2, wherein the single-site catalyst system includes a metallocene catalyst, an organometallic compound and an ionic compound.
  • 4. The lubricant composition of claim 1, wherein the liquid olefin copolymer has a coefficient of thermal expansion of 3.0 to 4.0.
  • 5. The lubricant composition of claim 1, wherein the liquid olefin copolymer has a bromine number of 0.1 or less.
  • 6. The lubricant composition of claim 1, wherein the alkylated phosphonium compound is included in an amount of 0.1 to 5.0 wt % in the lubricant composition.
  • 7. The lubricant composition of claim 1, wherein the liquid olefin copolymer is included in an amount of 0.1 to 30 wt % in the lubricant composition.
  • 8. The lubricant composition of claim 1, wherein the base oil is at least one selected from the group consisting of mineral oil, polyalphaolefin (PAO), and ester.
  • 9. The lubricant composition of claim 1, further comprising an additive selected from the group consisting of an antioxidant, a metal cleaner, an anticorrosive agent, a foam inhibitor, a pour-point depressant, a viscosity modifier, a wear-resistant agent, and combinations thereof.
  • 10. The lubricant composition of claim 1, wherein the lubricant composition has an SRV friction coefficient of 0.2 to 0.3.
  • 11. The lubricant composition of claim 1, wherein the lubricant composition has a traction coefficient of 0.15 to 0.3.
  • 12. The lubricant composition of claim 1, wherein the lubricant composition has a pinion torque loss rate due to friction of less than 1% in an FZG gear efficiency test.
  • 13. The lubricant composition of claim 1, wherein the lubricant composition is used as gear oil.
Priority Claims (1)
Number Date Country Kind
10-2019-0023683 Feb 2019 KR national