TWI467008B - Lubricant composition - Google Patents

Description

Lubricating oil composition

The present invention relates to a lubricating oil composition, and more specifically relates to a lubricating oil composition which suppresses noise generation and at the same time imparts fuel economy when operating a mechanical device filled with lubricating oil such as an internal combustion engine.

In recent years, the production and use of automobiles or industrial machinery of a world-scale scale has increased rapidly, and accordingly, the energy consumed by petroleum and the like has increased. Therefore, the air pollution caused by energy use is becoming more and more serious and has become a major problem.

In order to prevent such atmospheric pollution, it is necessary to reduce the exhaust gas emitted from automobiles and the like, which is the main source of atmospheric pollution, and to realize the fuel economy from the viewpoint of lubricating oil.

However, lubricating oils, for example, fuel-saving methods for lubricating oils for internal combustion engines (engine oils) are known to reduce the friction loss (stirring resistance) caused by engine oil, and it is known to reduce the viscosity (low viscosity) (for example, Patent Literature) 1 for reference).

However, the use of a low-viscosity base oil or the like simply reduces the viscosity of the lubricating oil, which causes a problem that the noise or vibration of the engine becomes large. This noise or vibration acts as a noise and vibration hazard, which is a cause of a great negative impact on the living environment.

Therefore, regarding the fuel-saving lubricating oil, it is desirable to make the lubricating oil low-viscosity, save fuel economy, and suppress noise. Development of lubricating oil compositions resulting from vibration.

[Patent Document 1] JP-A-2004-137317

The present invention provides excellent fuel economy and noise suppression in this situation. The composition of the lubricating oil produced by the vibration is intended.

The inventors of the present invention have diligently studied the results of the development of a lubricating oil composition having the above-described preferred properties, and found that the use of a specific base oil, together with an ethylene-α-olefin copolymer and/or polymethacrylate having a specific molecular weight, is adjusted. This can be achieved for a composition of a specific dynamic viscosity. The present invention has been completed based on relevant knowledge. That is, the present invention provides:

[1] A lubricating base oil having a dynamic viscosity of 3.5 to 10 mm ² /s and a viscosity index of 100 or more at 100 ° C, and (a) an ethylene-α-olefin copolymer having an average molecular weight of 2,500 to 25,000 And/or (b) a lubricating oil composition having a polymethacrylate having an average molecular weight of 10,000 to 30,000, and a lubricating oil composition having a dynamic viscosity of 5.6 to 15.0 mm ² /s at 100 ° C of the composition. ,

[2] The lubricating oil composition according to the above [1], wherein the dynamic viscosity at 100 ° C of the lubricating oil composition is 5.6 to 12.5 mm ² /s,

[3] The lubricant composition described in the above [1] or [2], wherein the dynamic viscosity of the lubricating base oil is 100 to 6 mm ² /s,

[4] Further comprising the above-mentioned [1] or [2] of an additive selected from at least one of an antioxidant, an extreme pressure agent, an antiwear agent, an oiliness agent, a detergent dispersant, a viscosity index enhancer, and a pour point depressant. The lubricating oil composition described,

[5] The lubricating oil composition according to the above [1] or [2] for use in an internal combustion engine.

According to the present invention, it is possible to provide excellent fuel economy while suppressing noise. A lubricating oil composition produced by vibration.

[Best Mode for Carrying Out the Invention]

The base oil used in the lubricating oil composition of the present invention requires the use of a base oil having a dynamic viscosity at 100 ° C of 3.5 to 10 mm ² /s and a viscosity index of 100 or more.

When the dynamic viscosity at 100 ° C is less than 3.5 mm ² /s, there is a case where noise or vibration cannot be sufficiently prevented. When the dynamic viscosity exceeds 10 mm ² /s, the fuel economy performance is hindered. Therefore, the dynamic viscosity at 100 ° C is preferably 3.5 to 6 mm ² /s.

Further, the base oil used in the present invention has a viscosity index of 100 or more. When the viscosity index is 100 or more, the low-temperature viscosity of the composition is lowered to save fuel, and at the same time, the viscosity at a higher temperature can be suppressed from being lowered, and the effect of suppressing noise or vibration can be enhanced.

Therefore, the viscosity index of the base oil is preferably 110 or more, and more preferably 120 or more.

The base oil used in the present invention has a sulfur content of preferably 1000 ppm by mass or less, more preferably 500 ppm by mass or less. When the sulfur content is within 1000 ppm by mass, the stability of the composition can be improved.

The base oil in the lubricating oil composition of the present invention is not particularly limited as long as the above conditions are satisfied, and mineral oil and/or synthetic oil used in general lubricating oils can be used.

In the case of a mineral oil base oil, for example, the crude oil is subjected to an atmospheric distillation fraction, or the atmospheric residue obtained after atmospheric distillation is subjected to vacuum distillation to obtain a lubricating oil fraction for performing more than one solvent deasphalting, solvent extraction, Manufactured by a process such as hydrodecomposition, hydrodewaxing, solvent dewaxing, or hydrorefining, or a mineral oil wax or a gas-to-liquid wax produced by a gas-to-liquid process Base oil, etc.

Further, the synthetic oil base oil may, for example, be a poly-α-olefin such as polybutene or a hydrogenated product thereof or a 1-decene oligomer or a hydrogenated product thereof, di-2-ethylhexyl adipate, or di-2-ethylene Polyester esters such as diesters such as ethylhexyl sebacate, trimethylolpropane octanoate, pentaerythritol-2-ethylhexanoate, aromatic synthetic oils such as alkylbenzenes and alkylnaphthalenes, and polyalkanes a diol or a derivative thereof or the like.

In the present invention, the base oil may be a mineral oil base oil, a synthetic oil base oil or any mixture of two or more selected from among these. For example, one or more types of mineral oil base oil, one or more types of synthetic oil base oils, one or more types of mineral oil base oils, and a mixed oil of one or more types of synthetic oil base oils. In particular, it is preferred to use a mineral oil base oil obtained by purifying a hydrogenation decomposition treatment or a mixture of the base oil and a hydrogenated product of a poly-α-olefin such as a 1-decene oligomer.

In the present invention, the base oil may be any of a mixture of two or more selected from the group consisting of mineral oil base oils, synthetic oil base oils, and the like.

In the present invention, the component (a) is an ethylene-α-olefin copolymer having a number average molecular weight of 2,500 to 25,000.

Here, the number average molecular weight is less than 2,500, and the effect of suppressing noise or vibration is insufficient, and when it exceeds 25,000, the shear stability is lowered and it is difficult to maintain the effect. The preferred number average molecular weight of the ethylene-α-olefin copolymer is in the range of 2,500 to 5,000, in consideration of noise or vibration suppression and shear stability.

Further, the α-olefin used in the ethylene-α-olefin copolymer is preferably an α-olefin having 3 to 20 carbon atoms, such as propylene, 1-butene or 1-decene. Further, the ratio of ethylene to α-olefin is preferably in the range of 1:9 to 9:1 (mass ratio).

The ethylene-α-olefin copolymer of the component (a) may be used alone or in combination of two or more.

Further, the amount of the collocation is usually selected in the range of 0.1 to 20% by mass based on the total amount of the composition. When the amount is 0.1% by mass or more, the effect of suppressing noise or vibration can be obtained. When the amount is 20% by mass or less, the viscosity is high when there is no low temperature, and the shear stability is also good, and the effect can be stably maintained.

In the present invention, the component (b) is a polymethacrylate having a number average molecular weight of 10,000 to 30,000. The polymethacrylate may be non-dispersed or dispersed.

Here, the number average molecular weight is less than 10,000, and the effect of suppressing noise or vibration is insufficient, and in the case of more than 30,000, the shear stability is lowered, and it is difficult to maintain the effect. The preferred number average molecular weight of the polymethacrylate is in the range of 15,000 to 25,000, taking into consideration the suppression of noise or vibration and the stability of shearing.

The polymethacrylate of the component (b) may be used alone or in combination of two or more.

Further, the amount of the composition may be selected so as to satisfy the condition of the dynamic viscosity at 100 ° C of the composition of the present invention, and is usually selected in the range of 0.1 to 10% by mass based on the total amount of the composition. When the amount is 0.1% by mass or more, the fuel economy effect and the effect of suppressing noise or vibration can be obtained. When the amount is 10% by mass or less, the viscosity is too high when there is no low temperature, and the shear stability is also good. Maintain this effect with stability.

As described above, the present invention is a composition obtained by mixing the component (a) and/or the component (b) with a base oil, and further, various additives which are usually used in the lubricating oil can be used depending on the purpose of use.

For example, an additive selected from at least one selected from the group consisting of an antioxidant, an extreme pressure agent, an antiwear agent, an oily agent, a detergent dispersant, (a), (b) other viscosity index increasing agents, and a pour point depressant is good.

Antioxidant with phenolic antioxidants and/or amine antioxidants.

The phenolic antioxidant can be used by any suitable phenolic antioxidant which is used as an antioxidant of a conventional lubricating oil. The phenolic antioxidant, for example, 2,6-di-tert-butyl-4-methylphenol; 2,6-di-tert-butyl-4-ethylphenol; 2,4,6-tri- Tert-butylphenol; 2,6-di-tert-butyl-4-hydroxymethylphenol; 2,6-di-tert-butylphenol; 2,4-dimethyl-6-tert-butyl Phenol; 2,6-di-tert-butyl-4-(N,N-dimethylaminomethyl)phenol; 2,6-di-tert-pentyl-4-methylphenol; 4,4 '-Methylene double (2,6-di-tert-butylphenol), 4,4'-bis(2,6-di-tert-butylphenol), 4,4'-bis (2-A) -6-tert-butylphenol), 2,2'-methylenebis(4-ethyl-6-tert-butylphenol), 2,2'-methylenebis(4-methyl- 6-tert-butylphenol), 4,4'-butylene bis(3-methyl-6-tert-butylphenol), 4,4'-isopropylidene bis(2,6-di-tert -butylphenol), 2,2'-methylenebis(4-methyl-6-nonylphenol), 2,2'-isobutylene bis(4,6-dimethylphenol), 2, 2'-methylenebis(4-methyl-6-cyclohexylphenol), 2,4-dimethyl-6-tert-butylphenol, 4,4'-thiobis(2-methyl- 6-tert-butylphenol), 4,4'-thiobis(3-methyl-6-tert-butylphenol), 2,2'-thiobis(4-methyl-6-tert- Butylphenol), bis(3-methyl-4-hydroxy-5-tert-butylbenzyl) sulfide, double (3,5 -di-tert-butyl-4-hydroxybenzyl)sulfide, 2,2'-thio-divinylbis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propane Acid ester], tridecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, pentaerythritol-indole [3-(3,5-di-tert-butyl) 4-hydroxyphenyl)propionate], octyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, octadecyl-3-(3,5 Further, di-tert-butyl-4-hydroxyphenyl)propionate, octyl-3-(3-methyl-5-tert-butyl-4-hydroxyphenyl)propionate or the like is preferred.

Further, the amine-based antioxidant can be suitably selected from any of the known amine-based antioxidants used as an antioxidant of a conventional lubricating oil. The amine is an antioxidant, such as a diphenylamine system, specifically such as diphenylamine or monooctyldiphenylamine; monodecyldiphenylamine; 4,4'-dibutyldiphenylamine 4,4'-dihexyldiphenylamine;4,4'-dioctyldiphenylamine;4,4'-dimercaptodiphenylamine;tetrabutyldiphenylamine; tetrahexyldi Phenylamine; tetraoctyldiphenylamine: tetradecyldiphenylamine, such as alkylated diphenylamine having 3 to 20 carbon atoms, and naphthylamine, specifically as α -naphthylamine; phenyl-α-naphthylamine, further butylphenyl-α-naphthylamine; hexylphenyl-α-naphthylamine; octylphenyl-α-naphthylamine; An alkyl group having 3 to 20 carbon atoms such as phenyl-α-naphthylamine is substituted with phenyl-α-naphthylamine. Among these, the effect of the diphenylamine system is better than that of the naphthylamine series, particularly the alkylated diphenylamine having an alkyl group of 3 to 20, particularly 4,4'-di (C ₃ ~ C ₂₀ alkyl) diphenylamine is preferred.

In the present invention, the phenolic antioxidant may be used singly or in combination of two or more kinds. Further, the above-mentioned amine-based antioxidants may be used singly or in combination of two or more kinds. Further, one type or more of a phenolic antioxidant and one or more types of an amine antioxidant may be used in combination.

The amount of the antioxidant is preferably selected from the range of 0.05 to 3% by mass, more preferably 0.2 to 2% by mass, based on the total amount of the lubricating oil composition, from the viewpoint of balance of effects and economy.

Extreme pressure agents, anti-wear agents, such as zinc dithiophosphate, dithiocarbamic acid, disulfides, sulfurized olefins, sulfurized oils, sulfurized esters, thiocarbonates, Sulfur-containing anti-wear agents such as thiocarbamate; phosphites, phosphates, phosphonates, and phosphorus-containing anti-wear agents such as amine salts or metal salts; Phosphate, phosphorothioate, thiophosphonate and sulfur and phosphorus anti-wear agents such as amine or metal salts.

The oily agent (friction modifier) may be any compound generally used as a friction modifier for lubricating oils, for example, an alkyl group or an alkenyl group having 6 to 30 carbon atoms, particularly a carbon number of 6 to 30 in the molecule. An aliphatic amine having one linear alkyl group or a linear alkenyl group, a fatty acid ester, a fatty acid decylamine, a fatty acid, an aliphatic alcohol, an aliphatic ether or the like. The extreme pressure agent, the abrasion resistance agent, and the oil agent are generally in the range of 0.01 to 3% by mass, preferably 0.1 to 1.5% by mass.

Examples of the detergent dispersant include a sulfonate, a phenate, a salicylate, a carboxylate, a phosphonate, etc., which are an alkali earth metal such as Ca, Mg or Ba, which is a metal-based detergent. . Among these, the metal-based detergent is preferably a Ca sulfonate, a Ca salicylate or a Ca phenolate, and particularly a Ca which is highly alkaline (the base price of the perchloric acid method is 150 to 500 mgKOH/g). The sulfonate, Ca salicylate, and Ca phenate are preferred.

Further, an ashless dispersant such as succinimide succinimide (containing a boride), succinate or the like.

The amount of such a clean dispersant is usually in the range of 0.01 to 10% by mass, preferably 0.1 to 5% by mass.

(a) Other viscosity index-improving agents other than (b), for example, polymethacrylate other than the above, an olefin-based copolymer other than the above, a dispersed olefin-based copolymer, and a styrene-based copolymer ( For example, a styrene-diene copolymer, a styrene-isoprene copolymer, etc.). The amount of the viscosity index-increasing agent is usually from 0.5 to 15% by mass, preferably from 1 to 10% by mass.

In the present invention, it can be combined with other, a pour point depressant, an antifoaming agent, a surfactant, and the like.

The dynamic viscosity of the lubricating oil composition of the present invention at 100 ° C must be 5.6 to 15.0 mm ² /s. When the dynamic viscosity at a temperature of 100 ° C of the composition is less than 5.6 mm ² /s, there is a case where noise or vibration cannot be sufficiently prevented, and if it exceeds 15.0 mm ² /s, the performance of the fuel economy is hindered. Therefore, the dynamic viscosity at 100 ° C is preferably 5.6 to 12.5 mm ² /s.

The lubricating oil composition of the invention has excellent fuel economy and can suppress noise. The effect of vibration.

For example, the lubricating oil is used in an internal combustion engine, and is suitable as a fuel-saving internal combustion engine oil (engine oil), and when the engine is operated, it is possible to suppress noise particularly during acceleration operation. The generation of vibration. Therefore, it is particularly useful in the use of lubricating oil for internal combustion engines used in a four-wheeled vehicle or a two-wheeled vehicle equipped with a four-stroke engine.

[Examples]

Next, the present invention will be described in more detail by way of examples, but the invention is not limited thereto.

Moreover, noise and fuel economy are implemented by the following methods.

(1) Assessment of noise

The noise was measured by the following engine motoring apparatus and noise measuring method.

[Engine starting device and operating conditions]

Use engine: water cooled 600cc, 4-cylinder engine

Dynamic valve form: DOHC (direct strike type)

Engine revolutions: 3000rpm

Oil pan oil temperature: 100 ° C

Drive motor: 7.5KW

[Noise measurement method]

A power spectrum (dB) of the number of cycles of 6300 Hz was measured using a noise meter ("LA5560" manufactured by Ono Co., Ltd.) and a cycle number analyzer (Repolyzer XN-8100 manufactured by Ono Instruments).

(2) Assessment of fuel economy

Using the "engine engine" of the noise of (1), the fuel economy of the motor is measured by measuring the engine driving torque (Nm).

[Engine starting device and operating conditions]

Use engine: water cooled 600cc, 4-cylinder engine

Dynamic valve form: DOHC (straight hit)

Engine revolutions: 5000rpm

Oil pan oil temperature: 100 ° C

Drive motor: 7.5KW

Examples 1 to 5 and Comparative Examples 1 to 3

The lubricating oil was prepared using the base oils and additives of Table 1, and the noise and fuel economy were evaluated by the above methods. The result is shown in Table 1.

〔Note〕

1) Paraffinic mineral oil, 100 ° C dynamic viscosity 4.469 mm ² / s, viscosity index 127

2) Paraffinic mineral oil, 100 ° C dynamic viscosity 5.285mm ² / s, viscosity index 104

3) Paraffinic mineral oil, 100 ° C dynamic viscosity 10.89mm ² / s, viscosity index 107

4) Number average molecular weight 300,000

5) Number average molecular weight 21,000

6) Titanium alkyl dialkyl dithiophosphate having a P content of 8.6% by mass

7) Casulfonate: base price (perchloric acid method) 300 mgKOH/g, Ca content 12.5% by mass

8) nitrogen content of 1,8 mass%, boron content of 2.0% by mass,

9) nitrogen content of 2.3% by mass and boron content of 1.9% by mass

10) The nitrogen content is 1.0% by mass, and the boron content is 0% by mass.

11) Dialkyldiphenylamine

12) Number average molecular weight 2,600, 100 °C dynamic viscosity 600mm ² / s, viscosity index 240

13) Number average molecular weight 3,700, 100 ° C dynamic viscosity 2,000 mm ² / s, viscosity index 300

14) Defoamer

As is apparent from the first table, Examples 1 to 4 are ethylene-α-olefin copolymers A or B having a number average molecular weight of 2,600 or 3,700, and Example 5 is a polymethacrylate having a number average molecular weight of 21,000. Moreover, the properties of any of the base oils and the 100 ° C dynamic viscosity of the composition are those satisfying the requirements. These lubricating oil compositions of the present invention can reduce noise and have excellent fuel economy performance.

On the other hand, Comparative Examples 1 and 2, which do not have the ethylene-α-olefin copolymer or polymethacrylate having the number average molecular weight necessary for the present invention, are insufficient in noise reduction property and fuel economy. Further, in the case of using an ethylene-α-olefin copolymer having a number average molecular weight of 3,700, Comparative Example 3 having a 100 ° C dynamic viscosity of the composition of 15.4 mm ² /s was inferior in fuel economy.

[industrial use]

When the lubricating oil of the present invention is used in various mechanical devices including internal combustion engines, it exhibits excellent fuel economy and can suppress noise. A lubricating oil composition produced by vibration. Therefore, it is advantageous as a lubricating oil that prevents air pollution and noise and vibration.

Claims (4)

A lubricating oil composition for an internal combustion engine oil, which uses a lubricating base oil having a dynamic viscosity of 3.5 to 10 mm ² /s at a temperature of 100 ° C and a viscosity index of 110 or more, and is matched with (a) a number average of 0.1 to 20% by mass. A lubricating oil composition comprising an ethylene-α-olefin copolymer having a molecular weight of 2,500 to 5,000 and/or (b) 0.1 to 10% by mass of a polymethacrylate having a number average molecular weight of 10,000 to 25,000, wherein The dynamic viscosity of the composition at 100 ° C is 5.6 to 15.0 mm ² /s. The lubricating oil composition of claim 1, wherein the lubricating oil composition has a dynamic viscosity at 100 ° C of 5.6 to 12.5 mm ² /s. The lubricating oil composition according to claim 1 or 2, wherein the lubricating base oil has a dynamic viscosity at 100 ° C of 3.5 to 6 mm ² /s. For example, the lubricating oil composition of claim 1 or 2 is further matched with an antioxidant, an extreme pressure agent, an antiwear agent, an oily agent, a detergent dispersant, a viscosity index enhancer, and a pour point depressant. The additive of at least one selected is selected.