JP2000063878A - Non-stage transmission oil composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a CVT lubricating oil which has a high coefficient of friction capable of transmitting a high output engine power and, in addition, is excellent in wear proofness. SOLUTION: A non-stage transmission oil composition is obtained by formulating (a) a polymethacrylate, (b) one or more substances selected from alkaline earth metal phenolates and alkaline earth metal sulfonates, (c) an imide compound, (d) a disulfide compound, and (e) a zinc dithiophosphonate into a lubricating oil base oil.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a continuously variable transmission oil composition, and particularly to a metal belt type continuously variable transmission lubricating oil composition having a high friction coefficient, excellent durability of the friction coefficient, and less wear. Regarding

[0002]

2. Description of the Related Art In recent years, the emission of carbon dioxide has been restrained in accordance with measures to prevent global warming. Therefore, it is required to further improve the fuel economy of automobiles. The main type of automatic transmission (AT) for automobiles is a combination of a torque converter, a wet clutch, and a planetary gear. However, since this torque converter transmits power via automatic transmission fluid (ATF), the loss is large. For this reason, the power transmission loss is reduced by the lockup, but it is difficult to reduce the transmission loss drastically as long as the torque converter is used.

Therefore, there is a movement to adopt a continuously variable transmission (CVT) using a metal belt. The belt type CVT is composed of a drive pulley and a belt for transmitting power, and the belt is composed of an element and a steel strip holding the element. With this transmission, transmission loss can be significantly reduced. However, when the engine output is large, slippage between the belt and the pulley is likely to occur, and so far, it has been usually used for automobiles with a small displacement.
However, due to the demand for fuel efficiency, there is a trend toward adoption in high-power engines.

In order to efficiently transmit the engine output, it is necessary to prevent the pulley and the belt from slipping. However, if the pressure for sandwiching the belt is increased in order to prevent slippage, the belt is easily worn. For this reason, not only is the surface of the device improved, but there is also a demand for a lubricating oil that prevents the belt and pulley from slipping and wears the belt and pulley. In other words, it has become necessary to have a lubricant having a frictional force of a certain level or more so as to prevent slippage between the pulley and the belt for sufficient power transmission while having lubricity for preventing wear.

Japanese Unexamined Patent Publication No. 9-25491 discloses a CVT.
In order to eliminate the "scratch phenomenon" in (1), the lubricant base oil (a) is an overbased detergent such as an alkylaryl sulfonate overbased with an alkali metal or an alkaline earth metal, and (b) diisooctyldithiophosphorus. An additive package comprising a metal dialkyldithiophosphate such as zinc acidate, a sulfur-containing friction modifier such as (c) a sulfurized olefin and a sulfurized fatty acid, (d) a fatty acid amide, and (e) a viscosity improver such as a polyolefin is added. A lubricating oil is disclosed.

Japanese Unexamined Patent Publication No. 9-78079 discloses AST.
Using the LFW-1 test method specified in MD2714, a vertical load of 200 lb and a sliding speed of 0 to 1
The friction coefficient measured from the frictional force at each sliding speed in the range of 00 cm / s shows a positive friction characteristic in which the friction coefficient increases with the sliding speed, and the sliding speed is 2.
The coefficient of friction of sliding speed of 5 cm or less is 0.12 to 0.14
Have proposed a lubricating oil that is in the range of. Specifically, it is a lubricating oil containing a base oil such as a mineral oil or a synthetic oil, a sulfurized ester, a metal salt-based detergent, zinc dialkyldithiophosphate, a phosphoric acid ester, an imide compound, and a polymethacrylate. It is said that the use of this lubricating oil enables transmission of a large amount of power and suppresses a stick-slip phenomenon due to slipping between metals.

JP-A-9-100487 discloses that a lubricating base oil contains at least one sulfur-based extreme pressure agent selected from sulfurized fats, thiocarbamates, and thioterpenes, tricresyl phosphate, and alkyl acid. For a continuously variable transmission prepared by blending one or more phosphorus-based extreme pressure agents selected from a phosphate ester amine salt and an alkenyl acidic phosphate ester amine salt and an alkaline earth metal detergent such as calcium phenate. A lubricating oil composition is disclosed. As a result, the wear resistance and extreme pressure are excellent, and the friction coefficient can be kept high for a long time, so that a large torque can be transmitted.

JP-A-9-263782 discloses a base oil containing a viscosity index improver if necessary, an ashless dispersant such as a sulfonate or an imide compound, an acid amide, molybdenum dithiophosphate, or dithiocarbamine. Disclosed is a continuously variable transmission oil composition containing an organic molybdenum compound such as molybdenum acid and an amine-based antioxidant. This composition
The minimum friction coefficient at 100 ° C. is 0.1 or more, and the ratio μs / μd between the friction coefficient μd at the sliding speed V and the friction coefficient μs immediately before the sliding speed becomes 0 is smaller than 1. It also states that it may contain a fatty acid derivative, a partial ester compound, a sulfur-based antioxidant, and the like. As a result, the friction coefficient can be maintained for a long period of time, and the scratch phenomenon can be prevented.

[0009]

However, although the above-mentioned documents focus on improving the friction coefficient, in order to transmit high-power engine power, further improvement in terms of the friction coefficient is required. Required. Further, the wear preventing performance is not sufficient, and improvement has been demanded.

[0010]

DISCLOSURE OF THE INVENTION The inventors of the present invention have made earnest studies on a lubricating oil for a metal belt type CVT capable of achieving both wear prevention and a high friction coefficient. As a result, (a) polymethacrylate,
A lubricating oil containing (b) one or more kinds selected from an alkaline earth metal phenate and an alkaline earth metal sulfonate, (c) an imide compound, (d) a disulfide compound, and (e) zinc dithiophosphate, It has been found that the above problems are satisfied.

Here, the disulfide compound is represented by Formula 1, and the compounding amount thereof is 0.3 to 3.
It is 0 mass%.

[0012]

## EQU1 ## R-S-S-R '(R and R'are an alkyl group, a phenyl group, an aryl group,
Aminophenyl group, nitrophenyl group, furfururi group,
An aminonaphthyl group, a pyridyl group, a benzyl group, R
And R'may be the same or different)

The polymethacrylate is a dispersion type, and its compounding amount is 5 to 15% by mass based on the continuously variable transmission oil. The alkaline earth metal phenate and alkaline earth metal sulfonate are one or more selected from a calcium salt, a magnesium salt, and a barium salt, and the blending amount thereof is 0.5 to 3. 0 mass%
Is. The imide compound is succinimide and / or boron-containing succinimide, and the compounding amount thereof is 0.5 to 5.0 mass% based on the continuously variable transmission oil. Further, the zinc dithiophosphate is a commonly available compound of dithiophosphoric acid having an alkyl and / or aryl group, and its compounding amount is 0.05 to 0.2 mass as zinc on the basis of continuously variable transmission oil. %. It has been found that when such a combination is used, wear prevention and a high friction coefficient are exhibited, and the present invention has been completed.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in more detail below. As the lubricating base oil used in the present invention, known mineral oils and / or synthetic oils can be used. For example, by a known method, neutral oil produced from crude oil as a raw material, bright stock, or atmospheric distillation oil is subjected to extraction treatment with a solvent such as furfural, and the resulting raffinate is dewaxed with a solvent such as methyl ethyl ketone. Examples thereof include those obtained by further purifying hydrogen under high pressure to remove impurities such as sulfur. Examples of synthetic oils include poly-α-olefins, polyhydric alcohol esters, polyalkylene glycols and the like.

In the present invention, it is preferable to contain a substrate having a viscosity index of 120 or more in an amount of 30% by mass or more, preferably 50% by mass or more. Examples of such a base material include waxes, hydroisomerized highly refined hydrotreated oils, and synthetic oils. If the base material having a viscosity index of 120 or more falls below 30% by mass, the life of the continuously variable transmission oil may be shortened.

As the polymethacrylate, a dispersion type can be preferably used. Such a polymer can be obtained by copolymerization of an alkyl methacrylate monomer and a polar monomer. As the polar monomer, one or more selected from diethylaminoethyl methacrylate, 2-methyl-5-vinylpyrrolidone, N-vinylpyrrolidone and morpholinoethylmethacrylate can be preferably used. The molar ratio of the alkyl methacrylate monomer to the polar monomer is 80: 20-9, which maximizes the dispersion effect.
The range of 5: 5 is preferable. Also, regarding the molecular weight of the polymer, from the viewpoint of shear stability, etc., the number average molecular weight is 1
The thing of the range of 0000-100000 can be used conveniently. The amount of polymethacrylate added is 5 to 15% by mass, preferably 7 to 12% by mass based on the total amount of continuously variable transmission oil. If the amount is less than 5% by mass, the low temperature startability and the wear preventing effect may decrease. Further, even if it exceeds 15% by mass, the effect of preventing wear may decrease, which is not preferable.

Among the alkaline earth metal phenates and alkaline earth metal sulfonates, one or more selected from calcium, magnesium and barium can be used as the alkaline earth metal. However, one or more selected from calcium and magnesium is preferable from the viewpoint of improving the friction coefficient.

The amount of one or more selected from alkaline earth metal phenates and alkaline earth metal sulfonates is 0.5 to 3.0 based on the total amount of continuously variable transmission oil.
It is mass%, preferably 0.7 to 2.0 mass%. 0.
If it is less than 5% by mass, the durability of the friction coefficient and the cleaning action may be insufficient. On the other hand, if it exceeds 3.0% by mass, the coefficient of friction may decrease, which is not preferable.

The imide compound used in the present invention is a succinimide and / or a boron-containing succinimide. Those having an alkenyl group can be preferably used. This alkenyl succinimide is used to disperse insoluble substances, sludge and the like generated by the oxidation of organic substances, but the reduction of the friction coefficient is relatively small, and the effect of reducing the temporal change of the friction coefficient is observed.

The amount of succinimide and / or boron-containing succinimide added is 0.5 based on the total amount of continuously variable transmission oil.
˜5.0 mass%, preferably 1.0 to 3.0 mass%. If it is less than 0.5% by mass, the friction coefficient and the dispersion effect may be lowered, which is not preferable. On the other hand, if it exceeds 5.0% by mass, abrasion resistance is deteriorated, which is not preferable.

The disulfide compound used in the present invention is represented by the above-mentioned formula 1, and its compounding amount is 0.3 to 3.0% by mass, preferably 0.5 to 2.0% by mass based on the continuously variable transmission oil. Is. If the amount added is less than 0.3% by mass, the friction coefficient will be low, and the characteristics as a continuously variable transmission oil may not be sufficient. Further, even if it exceeds 3.0% by mass, further improvement in performance cannot be seen, which is not preferable.

When R and R'in Formula 1 are alkyl groups, those having 2 to 15 carbon atoms can be used. More specifically, ethyl group, n-propyl group, i-propyl group, n-
One selected from a butyl group, a t-butyl group, an s-butyl group, and a t-octyl group is easily available as a single substance. However, industrially, one synthesized with a branched alkyl group having almost the same carbon number can be obtained at low cost. Therefore, it can be said that it is preferable to select from a pentyl group having a branched chain, a hexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group, an undecyl group, a dodecyl group, a tridecyl group, a tetradecyl group, and a heptadecyl group.

As the aryl group, a p-tolyl group is preferable in terms of easy availability. However, it is not necessary to limit the number of carbon atoms in the alkyl chain to 1, and a mixture of 1 to 3 may be used. Further, there is no problem if the number of alkyl chains is not only one but two.

The aminophenyl group is preferably a p-aminophenyl group, and the nitrophenyl group is preferably a p-nitrophenyl group from the viewpoint of easy availability. However, there is no problem even if the m-position is substituted. Therefore, there is no problem even if a mixture of p-position and m-position is used.

As the aminonaphthyl group, a 1-aminonaphthyl group is preferable from the viewpoint of easy availability. However, 2-,
There is no problem even if the 3- and 4-positions are used. Therefore, there is no problem even if a mixture of 1-, 2-, 3- and 4-positions is used.

As the pyridyl group, 2-pyridyl group, 4-
A pyridyl group and a mixture of both can be used without any particular limitation.

The zinc compound of dithiophosphoric acid to be added to the base oil, which can be usually available.
Specifically, the hydrocarbon group of dithiophosphoric acid has 3 to 1 carbon atoms.
1 type or 2 types selected from a primary alkyl group of 1, a secondary alkyl group of 3 to 18 carbon atoms, a β-position branched alkyl group of 3 to 18 carbon atoms, a phenyl group and an aryl group of 7 to 18 carbon atoms. That is all. Among these, when used as a continuously variable transmission oil, a phenyl group or an aryl group is preferable from the viewpoint of stability of the friction coefficient. In addition, secondary alkyl groups have excellent wear-preventing effect, and primary alkyl groups and β-position branched alkyl groups have excellent stability against heat and oxidative deterioration. It is preferable to change the mixing ratio.

From the above points, when used as the continuously variable transmission oil of the present invention, the main component is zinc dithiophosphate having a phenyl group and an aryl group, and 10 parts by weight thereof and 1 to 20 parts by weight of a primary alkyl group. A combination of zinc dithiophosphates having a is preferably used. However, it is not necessary to stick to this combination, and there is no problem using an easily available one.

Further, it is inevitable that dithiophosphoric acid having one hydrocarbon group is mixed as an impurity, but it can be used as it is as long as the solubility in the base oil is not a problem.

The amount of the zinc compound of dithiophosphoric acid added is 0.05 to 0.
It is 2 mass%, and 0.074 to 0.2 mass% is more preferable. If the addition amount is less than 0.05% by mass, not only the coefficient of friction decreases but also the effect of preventing wear decreases, which is not preferable. Further, even if it exceeds 0.2% by mass, further improvement in performance cannot be seen, which is not preferable.

Besides, a fatty acid alkanolamide can be used as a friction modifier. As the fatty acid of the fatty acid alkanolamide, those having 7 to 22 carbon atoms, preferably 8 to 20 carbon atoms can be used. Specific examples include saturated fatty acids such as octanoic acid, decanoic acid, dodecanoic acid, tetradecanoic acid, hexadecanoic acid, octadecanoic acid, unsaturated fatty acids such as oleic acid, mixtures thereof, and naturally occurring fatty acids. . Among these, unsaturated fatty acids such as oleic acid can be preferably used because they have a lower melting point. Examples of amines include diethanolamine, monoethanolamine, monoiso-propanolamine, and mixtures thereof.

Those obtained from the above fatty acids and amines include dodecanoic acid (lauric acid) monoethanolamide, dodecanoic acid diethanolamide, octadecanoic acid diethanolamide, octadecanoic acid monoethanolamide, oleic acid diethanolamide, and oleic acid monoethanolamide. , Coconut oil fatty acid diethanolamide, coconut oil fatty acid monoethanolamide, tetradecanoic acid (myristic acid) diethanolamide, tetradecanoic acid monoethanolamide, dodecanoic acid tetradecanoic acid diethanolamide, hexadecanoic acid (palmitic acid) diethanolamide, hexadecanoic acid monoethanolamide , Dodecanoic acid isopropanolamide, iso-octadecanoic acid diethanolamide, iso-octadecanoic acid monoethanolamide, per Kernel oil fatty acid diethanolamide,
Although palm kernel oil fatty acid monoethanolamide and the like can be mentioned, dodecanoic acid diethanolamide, oleic acid diethanolamide, and coconut oil fatty acid diethanolamide are preferable among them in view of easy availability.

A method for producing a fatty acid alkanolamide, which is a method of adding twice the molar amount of diethanolamine, monoethanolamine or monoiso-propanolamine to a predetermined amount of fatty acid, and heating and dehydration condensation under a nitrogen stream, etc. Can be used. As in the case of the N-alkyl propylene diamine fatty acid salt, the fatty acid used does not have to be a single component, and there is no problem using a mixture of two or more kinds or a naturally derived fatty acid.

In addition to the above additives, antioxidants, rust preventives, pour point depressants, metal deactivators, etc., which have been conventionally used in lubricating oils, are used within the range not impairing the object of the present invention. Can also be added as appropriate.

As the antioxidant, a phosphorus-based antioxidant,
A phenolic antioxidant and an amine antioxidant are used alone or as a mixture. The amount of antioxidant added is about 0.1 to 3.0% by mass based on the total amount of continuously variable transmission oil.
If the amount is less than 0.1% by mass, the antioxidant ability may be insufficient. On the other hand, if it exceeds 3.0% by mass, sludge generation due to an increase in the concentration of oxidative decomposition products may be caused, or the friction coefficient may be lowered, which is not preferable.

As the phosphorus-based antioxidant, bis (2,4
-Di-t-butylphenyl) pentaerythritol diphosphite, phenyldiisodecylphosphite, diphenyldiisooctylphosphite, diphenyldiisodecylphosphite, triphenylphosphite, trisnonylphenylphosphite, tris-di-nonylphenylphosphite , Tris- (2,4-di-t-butylphenyl) phosphite, distearyl-pentaerythritol diphosphite, bis (nonylphenyl) pentaerythritol diphosphite, 4,4'-isopropylidene diphenol alkyl phosphite , 4, 4 '
-Butylidene bis (3-methyl-6-t-butylphenyl di-tridecyl phosphite), 1,1,3-tris (2-methyl-4-di-tridecyl phosphite-5-
t-butylphenyl) butane, tetrakis (2,4-di-t-butylphenyl) -4,4'-bisphenylene diphosphite, 3,4,5,6-dibenzo-1,2-oxaphosphane- 2-oxide, trilauryltrithiophosphite, tris (isodecyl) phosphite,
Tris (tridecyl) phosphite, phenyldi (tridecyl) phosphite, diphenyltridecylphosphite, phenyl-bisphenol A pentaerythritol diphosphite, 3,5-di-t-butyl-
4-hydroxybenzylphosphonic acid diethyl ester and the like can be mentioned, and one or more of these can be used.

Among these, aryl phosphites,
In particular, it is preferable that one aryl group has at least one, and preferably two alkyl groups, from the viewpoint of hydrolysis stability, and tris- (2,4-di-t-butylphenyl) phosphite, tris Nonylphenyl phosphite, tris- (mono & di mixed nonylphenyl) phosphite and the like can be preferably used. In addition, especially when an industrial grade reagent is used, the hydrocarbon group is 1 to
It is unavoidable that two things are mixed. However, as long as the solubility in the base oil does not matter, it can be used as it is.

Examples of the phenol-based antioxidant which can be used in the present invention include 2,6-di-t-butylphenol, 2-t-butyl-4-methoxyphenol and 2,4.
-Dimethyl-6-t-butylphenol, 2,4-diethyl-6-t-butylphenol, 2,6-di-t-butyl-p-cresol, 2,6-di-t-butyl-4-
Ethylphenol, 2,6-di-t-butyl-4-hydroxymethylphenol, 2,6-di-t-butyl-4
-(N, N-dimethylaminomethyl) phenol, n-
Octadecyl-β- (4'-hydroxy 3 ', 5-di-
t-Butylphenyl) propionate, 2,4- (n-
Octylthio) -6- (4-hydroxy3 ′, 5′-di-t-butylanilino) -1,3,5-triazine, styrenated phenol, styrenated cresol, tocophenol, 2-t-butyl-6- ( 3'-t-butyl-
5'-methyl-2'-hydroxybenzyl) -4-methylphenyl acrylate, 2,2'-methylenebis (4
-Methyl-6-t-butylphenol), 2,2'-methylenebis (4-ethyl-6-t-butylphenol), 2,2'-methylenebis (4-methyl-6-cyclohexylphenol), 2,2'- Dihydroxy-
3,3′-di (α-methylcyclohexyl) -5,5 ′
-Dimethyldiphenylmethane, 2,2'-ethylidene-
Bis (2,4-di-t-butylphenol), 2,2 '
-Butylidene-bis (4-methyl-6-t-butylphenol), 4,4'-methylenebis (2,6-di-t-)
Butylphenol), 4,4'-butylidene bis (3-
Methyl-6-t-butylphenol), 1,6-hexanediol bis [3- (3,5-di-t-butyl-4-)
Hydroxyphenyl) propionate], triethyleneglycol-bis-3-(-t-butyl-4-hydroxy-5-methylphenyl) propionate, N, N'-
Bis- [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyl] hydrazine, N, N'-hexamethylenebis- (3,5-di-t-butyl-4-hydroxy) hydrocinnamide , 2,2'-thiobis (4
-Methyl-6-t-butylphenol), 4,4'-thiobis (3-methyl-6-t-butylphenol),
2,2-thiodiethylenebis- [3 (3,5-di-t-
Butyl-4-hydroxyphenyl) propionate],
Bis [2-t-butyl-4-methyl-6- (3-t-butyl-5-methyl-2-hydroxybenzyl) phenyl] terephthalate, 1,1,3-tris (2-methyl-4-hydroxy-) 5-t-butylphenyl) butane,
1,3,5-Trimethyl-2,4,6-tris (3,5
-Di-t-butyl-4-hydroxybenzyl) benzene, tris (3,5-di-t-4-hydroxybenzyl) isocyanurate, 1,3,5-tris (4-t-)
Butyl-3-hydroxy-2,6-dimethylbenzyl)
Isocyanurate, tetrakis [methylene-3-
(3 ′, 5′-Di-t-butyl-4-hydroxyphenyl) propionate] methane, calcium (3,5-di-t-butyl-4-hydroxybenzylmonoethylphosphonate), propyl gallate, gallic acid Octyl acid,
Lauryl gallate, 2,4,6-tri-t-butylphenol, 2,5-di-t-butylhydroquinone, 2,5
-Di-t-amylhydroquinone, 1,1,3-tris-
(2-Methyl-4-hydroxy-5-t-butylphenyl) butane, 1,3,5-trimethyl-2,4,6-tris- (3,5-di-t-butyl-4-hydroxybenzyl) Benzene, 3,9-bis [2- {3- (3-t-
Butyl-4-hydroxy-5-methylphenyl) propionyloxy} -1,1-dimethylethyl] -2,8,
10-tetraoxaspiro [5,5] undecane and the like can be mentioned, and one or more of these can be used.

Among them, 2,6-di-t-butyl-p-cresol and 2,2'-methylenebis (4-methyl-6-) are easily available and are used in lubricating oils.
t-butylphenol), 2,2'-methylenebis (4
-Ethyl-6-t-butyl-4-ethylphenol),
4,4'-methylenebis (2,6-di-t-butylphenol) and the like are preferable.

Examples of amine-based antioxidants include p, p'-dioctyldiphenylamine, N-phenyl-N'-isopropyl-p-phenylenediamine, poly-2,2,4-trimethyl-1,2-dihydroquinoline,
6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline, thiodiphenylamine, 4-amino-p
-Diphenylamine, etc. can be mentioned, and these 1 type (s) or 2 or more types can be used.

Further, as the metal deactivator, for example, benzotriazole, tolyltriazole, carbon number 2 to
A benzotriazole derivative having 10 hydrocarbon groups,
Examples thereof include benzimidazole, an imidazole derivative having a hydrocarbon group having 2 to 20 carbon atoms, a thiazole derivative having a hydrocarbon group having 2 to 20 carbon atoms, 2-mercaptobenzothiazole, and the like. Can be used.

[0042]

EXAMPLES The present invention will be specifically described below with reference to a belt type CVT lubricating oil as an example. In addition, all of the examples illustrated as comparative examples are excellent ones that have reached a practical level. Therefore, the difference from the embodiment is small. But,
The CVT oil of the present invention is superior in characteristics to the comparative example. Moreover, the present invention is not limited to these examples.

(Test Method) The LFW-1 tester described in ASTM D2714 was used to examine the friction coefficient of the continuously variable transmission oil, the stability of the friction coefficient, and the lubricity. The test conditions were load: 200 lbf, rotation speed: 140 rpm, and oil temperature: 110 ° C. As the test piece, a standard product was used.

(Lubricating oil base oil) 40% by mass of a wax hydroisomerized base oil, 20% by mass of a solvent-dewaxing base oil and 40% by mass of a neutral oil were mixed. The kinematic viscosity of wax hydroisomerized oil is 20 mm ² / s, 100 at 40 ° C.
4.5 mm ² / s at ℃, flash point is 224 ℃, sulfur content is 10ppm, aromatic component by NDM ring analysis is 0
%, And the viscosity index is 142. The kinematic viscosity of solvent-dewaxed base oil is 96 mm ² / s at 40 ° C, 1 at 100 ° C.
1 mm ² / s, flash point 266 ° C., sulfur content 0.15% by mass, aromatic component by NDM ring analysis 6.5%, viscosity index 97. The kinematic viscosity of neutral oil is 4
12 mm ² / s at 0 ° C., 2.9 at 100 ° C.
mm ² / s, flash point 190 ° C., sulfur content 0.08 mass%, aromatic component by NDM ring analysis 13%, viscosity index 80.

(Additive) (a) Dispersion type polymethacrylate: Nitrogen dispersion type polymethacrylate (number average molecular weight is about 53000)

(B) Calcium phenate: base number 2
50 mg KOH / g

(C) Succinimide

(D1) dibenzyl disulfide (d2) t-octyl disulfide (d3) di-t-nonyl polysulfide (d4) sulfurized oil and fat (d5) 80 mass% of a sulfurized olefin, and a sulfurized ester 2
0 mass% mixture

(E) ZnDTP: Zinc dialkyldithiophosphate having a primary alkyl group in which the alkyl group has 8 carbon atoms

(F) Amine antioxidant:

Example 1 (a) polymethacrylate (a) 7.0% by mass, (b) calcium phenate 1.3% by mass and (c) succinimide 2 were added to the above base oil. 0.0% by mass, 0.047% by mass of zinc alkyldithiophosphate (e) as zinc, and 0.3% by mass of the antioxidant (f) were added. In addition, (d1)
Dibenzyl disulfide was added so as to be 0.9% by mass to obtain a continuously variable transmission oil composition. The concentration is a value based on the total amount of continuously variable transmission oil. The results of the LFW-1 test are shown in Table 1. Not only does the high friction coefficient appear from the initial stage of the test, but the change in the friction coefficient is small.

Example 2 A continuously variable transmission oil composition was prepared in the same manner as in Example 1 except that the amount of (d1) dibenzyl disulfide added in Example 1 was changed to 0.45% by mass.
The results of the LFW-1 test are shown in Table 1. Not only does the high friction coefficient appear from the initial stage of the test, but the change in the friction coefficient is small.

(Example 3) In place of (d1) dibenzyl disulfide of Example 1, 1.0% by mass of t-octyl disulfide of (d2) was added, and steplessly carried out in the same manner as in Example 1. A transmission oil composition was prepared. The results of the LFW-1 test are shown in Table 1, which shows a high friction coefficient from the initial stage of the test.

Example 4 A continuously variable transmission oil composition was prepared in the same manner as in Example 1 except that 0.7% by mass of coconut oil diethanolamide was added to the composition of Example 1. LF
The results of the W-1 test are shown in Table 1. Not only is the coefficient of friction high, but the coefficient of friction is not significantly reduced and wear is small.

(Comparative Example 1) In place of (d1) dibenzyl disulfide of Example 1, 0.7% by mass of di-t-nonylpolysulfide (d3) was added, and steplessly carried out in the same manner as in Example 1. A transmission oil composition was prepared. LFW-1
The results of the test are shown in Table 1, but the coefficient of friction is small.

(Comparative Example 2) In place of the (d1) dibenzyl disulfide of Example 1, 0.5% of the sulfurized fat and oil of (d4) was used.
A continuously variable transmission oil composition was prepared in the same manner as in Example 1 except that the amount of the compound was added by mass. The results of the LFW-1 test are shown in Table 1, but the coefficient of friction is small.

(Comparative Example 3) Instead of the (d1) dibenzyl disulfide of Example 1, a sulfurized olefin 8 of (d5) was used.
A mixture of 0% by mass and 20% by mass of sulfurized ester is added to 0.6
A continuously variable transmission oil composition was prepared in the same manner as in Example 1 except that the amount of the compound was added by mass. The results of the LFW-1 test are shown in Table 1, which shows that the friction coefficient is small and the wear is large.

[0058]

[Table 1]

[0059]

As described above, when the continuously variable transmission oil composition of the present invention is used, the power transmission loss is small and the wear is small because the friction coefficient is high. Therefore, it can be used for a large-capacity belt type CVT, and it becomes possible to popularize automobiles with excellent fuel economy.

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Claims (6)

[Claims] 1. A lubricating base oil comprising at least one selected from (a) polymethacrylate, (b) alkaline earth metal phenate and alkaline earth metal sulfonate, and (c).
Imide compound, (d) disulfide compound, and (e)
A continuously variable transmission oil composition containing zinc dithiophosphate. 2. The continuously variable transmission oil composition according to claim 1, wherein the polymethacrylate is a dispersion type and the compounding amount thereof is 5 to 15% by mass based on the continuously variable transmission oil. 3. The alkaline earth metal phenate and alkaline earth metal sulfonate are one or more selected from a calcium salt, a magnesium salt and a barium salt, and the compounding amount thereof is 0 based on the continuously variable transmission oil. .5-3.0
The continuously variable transmission oil composition according to any one of claims 1 and 2, wherein the composition is mass%. 4. The imide compound is succinimide and / or boron-containing succinimide, and the compounding amount thereof is 0.5 to 5.0 mass% based on the continuously variable transmission oil. The continuously variable transmission oil composition according to any one of claims 1 to 3. 5. The disulfide compound is represented by the formula (1), and the compounding amount thereof is 0.3 to 3.
It is 0 mass%, The continuously variable transmission oil composition of any one of Claims 1-4 characterized by the above-mentioned. R-S-S-R '... (1) (R and R'are an alkyl group, a phenyl group, an aryl group,
Aminophenyl group, nitrophenyl group, furfururi group,
An aminonaphthyl group, a pyridyl group, a benzyl group, R
And R'may be the same or different) 6. The zinc dithiophosphate is added in an amount of 0.05 to 0.2% by mass as zinc (based on continuously variable transmission oil). The continuously variable transmission oil composition according to the item.