ES2402946T3 - Composition of long-lasting engine oil that saves fuel - Google Patents

Abstract

A long-life motor oil composition that saves fuel comprising: a mineral oil and / or a synthetic base oil; an amine antioxidant consisting of diphenylamine and / or phenylnaphthylamine, as shown by the following general formula (4) or (5), in which each R6, R7, R8 and R9 can be a hydrocarbon group having 3 to 20 carbon atoms ** Formula ** and a phenolic antioxidant shown by the following general formula (2): ** Formula ** in which R5 is a hydrocarbon group having 3 to 20 carbon atoms, in an amount of 1.2% by mass or more in total and the proportion (mass: N / O) of nitrogen content (N) of the amine antioxidant with respect to oxygen content (O) of the phenolic antioxidant of 0 , 20 to 0.50; and molybdenum dithiocarbamate (MoDTC) in an amount of 0.055% by mass or more as an element of 20 molybdenum (Mo).

Description

Composition of long-lasting engine oil that saves fuel

Field of the Invention

The present invention relates to a long-lasting and fuel-saving engine oil composition, which exhibits excellent oxidation stability at elevated temperature and maintains a low friction property for a long time.

Prior art

In recent years, there has been a growing demand to improve the autonomy of cars avoiding the emission of CO2, in order to avoid global warming. It is important to improve the efficiency of the engines in order to improve the fuel efficiency of cars. Therefore, poor mixing technology and direct injection technology for gasoline engines have been used. On the other hand, because the reduction of friction in engines can contribute to the reduction of fuel consumption, the use of a low friction material for sliding parts and the use of a motor oil that saves fuel.

In order to prepare a fuel-saving engine oil, it is known that it is effective to reduce the viscosity of the engine oil to a low viscosity of 5W-20 or 0W-20 specified in the J300 viscosity classification of the Society of Automotive Engineers ( SAE) and simultaneously mix an organomolibdene friction modifier such as molybdenum dithiocarbamate (MoDTC) as an additive (friction modifier, hereinafter abbreviated as "FM") that reduces friction (see document 1 that is not patent ).

Because the poor mixing engine or direct injection engine exhibits high efficiency compared to conventional engines, the combustion temperature tends to increase and the piston and the like are exposed to a higher temperature. Therefore, it is necessary to improve the stability of the engine oil at elevated temperature. Specifically, the fuel-saving engine oil is required, in the future, to exhibit excellent stability against high temperature oxidation, as compared to conventional engine oil.

On the other hand, MoDTC deteriorates during use and disappears in the oil. As a result, the fuel-saving effect of MoDTC also deteriorates along with the duration of use. Therefore, it is an important issue to improve the sustainability of the fuel saving effect.

[Patent document 1] JP-A-10-17883 [Non-patent document 1] K. Hoshino et al., Fuel Efficiency of SAE 5W-20 Friction Modified Gasoline Engine Oil, SAE Technical Paper 982506 (1998).

Description of the invention

Problems to be solved by means of the invention

In view of the situation, an object of the present invention is to provide an engine oil that exhibits excellent oxidation stability at elevated temperature and excellent fuel saving sustainability.

Means to solve the problems

The inventors of the present invention have carried out intensive studies in order to achieve the above objective. As a result, the inventors have found that a composition containing a mineral oil and / or a synthetic base oil and a specific antioxidant, in a specific proportion, and containing MoDTC in a certain amount or more is useful as a Long-life engine that saves fuel that exhibits excellent stability against high temperature oxidation. This discovery has led to the completion of the present invention.

Specifically, the present invention provides a motor oil composition comprising: a mineral oil and / or a synthetic base oil: an amine antioxidant and a phenolic antioxidant in an amount of 1.2% by mass or more in total and the proportion (mass: N / O) of nitrogen content (N) of the amine antioxidant with respect to oxygen content (O) of the phenolic antioxidant from 0.20 to 0.50; and molybdenum dithiocarbamate (MoDTC) in an amount of 0.055% by mass or more in the form of molybdenum element (Mo).

In particular, it is preferable that the composition comprises the amine antioxidant and the phenolic antioxidant in an amount of 1.5% by mass or more in total and that the proportion (mass: N / O) of nitrogen (N) content of the Amine antioxidant with respect to oxygen content (O) of the phenolic antioxidant is 0.20 to 0.35 and molybdenum dithiocarbamate (MoDTC) in an amount of 0.055% by mass or more in the form of molybdenum element (Mo ).

The specific choice of the amine antioxidant and the phenolic antioxidant is explained below in the claims and discussed below.

Effect of the invention

The long-lasting and fuel-saving engine oil composition according to the present invention having the configuration described above, exhibits excellent stability against high temperature oxidation, shows a small increase in viscosity even after a period for prolonged use, and maintains low friction for a long period of time. Therefore, the composition can be used for internal combustion engines such as the poorly mixed gasoline engine and the direct injection gasoline engine, in particular. It exhibits the particular effect that the composition thus reduces fuel consumption and maintains good autonomy for a long period of time.

Best way to carry out the invention

As the base oil used in the engine oil composition according to the present invention, the kinematic viscosity of the base oil at 100 ° C is preferably 3.5 to 5.0 mm2 / s, and more preferably 4.0 at 4.5 mm2 / s. Preferably, the viscosity index of the base oil is 110 to 160, and more preferably 120 to 140. As a mineral oil, a lubricating base oil of high viscosity index having a viscosity index of 120 or more is desirable. . A lubricating base oil of high viscosity index having a viscosity index of 120 or more can be obtained by subjecting an oil, produced by means of wax hydroisomerization or heavy oil hydrocracking, to a process of wax removal or hydroelimination of solvent wax. An example of these production methods is specifically described in detail below.

Wax hydroisomerization can be carried out by causing the contact of a wax, as raw material, which has a boiling point of 300 to 600 ° C and containing 20 to 70 carbon atoms (for example, paraffin wax obtained during the solvent wax removal of a mineral oil lubricant, or wax obtained by means of Fischer-Tropsch synthesis that synthesizes a liquid fuel from a hydrocarbon gas or the like) with a hydroisomerization catalyst (for example, a catalyst in that at least one of group 8 metals such as nickel and cobalt and group 6A metals such as molybdenum and tungsten is on a silica-alumina support, a zeolite catalyst, or a catalyst in which platinum or the like is found on a support containing zeolite), under hydrogen atmosphere of a hydrogen partial pressure of 5 to 14 MPa, at a temperature of 300 to 450 ° C, and a spatial velocity hor liquid aria (LHSV) from 0.1 to 2 h

1. It is preferable that the conversion rate of the linear paraffin is 80% or more and that the conversion rate to the light fraction be 40% or less.

Meanwhile, hydrocracking can be carried out by contacting a bright reserve material of atmospheric distillate, vacuum distillate, which has a boiling point of 300 to 600 ° C, and optionally obtained through hydrodesulfurization and hydrodesnitrification , with a hydrocracking catalyst (for example, a catalyst in which at least one of group 8 metals such as nickel and cobalt and group 6A metals such as molybdenum and tungsten is on a silica-alumina support), under hydrogen atmosphere with a hydrogen partial pressure of 7 to 14 MPa, at a temperature of 350 to 450 ° C, and a liquid hourly space velocity (LSHV) of 0.1 to 2 h-1. It is preferable that the rate of decomposition (reduction rate (mass%) of the fractions having a boiling point of 360 ° C or more in the product) is 40 to 90%.

A lubricant fraction is obtained by distillation of the light fraction from the oil obtained by means of the above hydroisomerization or hydrocracking. Because, generally, the present fraction has a high pour point and high viscosity and does not have a sufficiently high viscosity index, the wax is removed by means of wax removal to obtain a lubricating base oil having a% of Cp according to the ndM analysis of 80% or more, a pour point of -10 ° C or less and a viscosity index of 120 or more.

When the wax is removed by solvent removal of wax, it is preferable to separate the light fraction by means of distillation using a precision distillation device so that the content of the fraction having a boiling point, determined by means of distillation by gas chromatography, of 371 ° C or more and less than 491 ° C, is 70% by mass or more, in order to carry out solvent removal of wax effectively. Solvent wax removal can be carried out at a temperature of -15 to -40 ° C and a solvent / oil ratio of 2/1 to 4/1, using ethyl methyl ketone / toluene (volume ratio: 1 / 1) as a wax removal solvent.

When the wax is removed by means of wax hydroelimination, it is preferable that the light fraction be distilled to such an extent that the wax hydroelimination is not negatively affected, and the light fraction is separated by distillation using a device of distillation. precision distillation so that the content of the fraction having a boiling point, determined by means of gas chromatography distillation, of 371 ° C or more and less than 491 ° C is 71% by mass or more after hydroelimination of wax, from the point of view of effectiveness. Wax hydroelimination can be carried out by contacting the fraction with a catalyst of

5 zeolite under hydrogen atmosphere of a hydrogen partial pressure of 3 to 15 MPa, at a temperature of 320 to 430 ° C, and a liquid hourly space velocity (LHSV) of 0.2 to 4 h-1, so that the pour point of the resulting lubricating base oil is -10 ° C or less.

A lubricating base oil having a viscosity index of 120 or more can be obtained using the

10 previous method. The lubricating base oil can be optionally subjected to solvent refining or hydrotreatment.

As a synthetic oil, an alpha-olefin oligomer, a diester synthesized from a dibasic acid such as adipic acid and a monohydric alcohol, a polyol ester synthesized from a poly (alcohol) can be provided

Water) such as neopentyl glycol, trimethylolpropane or pentaerythritol and a monobasic acid, one of its mixtures and the like.

In addition, a mixed oil obtained by mixing an appropriate mineral oil with a synthetic oil can also be used as the base oil for the engine oil of the present invention.

MoDTC used in engine oil according to the present invention is shown by means of the following general formula (1):

carbon atoms, and X represents an oxygen atom or a sulfur atom, the proportion being in number of oxygen atoms with respect to sulfur atoms of 1/3 to 3/1. Preferably, R1 to R4 are alkyl groups, and particularly preferably branched alkyl groups having from 8 to 14 carbon atoms, and specifically a butyl group, a 2-ethylhexyl group, an isotridecyl group, a stearyl group and

30 similar. R1 to R4 present in a molecule can be the same or different. MoDTCs that differ in R1 to R4 can be used in combination of two or more.

The MoDTC content is preferably 0.055% by mass or more, particularly preferably 0.055 to 0.12% by mass, and more preferably 0.06 to 0.10% by mass, as the weight of molybdenum element. (Mo) included in the MoDTC with respect to the total weight of the engine oil.

As the antioxidant used in motor oil according to the present invention, a specific phenolic antioxidant and a specific amine antioxidant are used.

As the phenolic antioxidant used in motor oil according to the present invention, a phenol compound shown by means of the general formula (2) is used.

Wherein R5 is preferably a hydrocarbon group having 3 to 20 carbon atoms. As examples of a particularly preferred hydrocarbon group, an octyl group and a stearyl group can be provided.

Compounds of formula (3) can be used: As an amine antioxidant used in motor oil according to the present invention, a diphenylamine and / or a phenylnaphthylamine of general formulas (4) and (5) are used.

In general, the compound of formula (4) is obtained by reacting N-phenylbenzenamine with an alkene. In formula (4), R6 and R7 represent hydrocarbon groups. Each benzene ring can be substituted with five substituents (ten substituents in total). It is preferable that each benzene ring be substituted with at least one substituent. The number of carbon atoms in the hydrocarbon group is

10 preferably from 3 to 20. When the total number of R6 and R7 is two or more, each hydrocarbon group may be the same or different. A linear or branched alkyl group that varies from butyl group to nonyl group is more preferred.

15 in which R8 and R9 represent hydrocarbon groups having 3 to 20 carbon atoms. Although the formula

(5) show that the naphthyl group and the phenyl group are substituted with a substituent, at least one of these groups may be substituted with one or more substituents, or each group may be substituted with one or more substituents. When there are two or more R8 or R9, the R8 and R9 can be the same or different from each other. Preferably, R8 and R9 are alkyl groups having 6 to 12 carbon atoms, and particularly

The compound preferably presents either the naphthyl group or the phenyl group substituted with a substituent of a linear or branched octyl group to a nonyl group.

As the same antioxidant, the compounds shown by the general formulas (4) and (5) can be used in combination.

Preferably, the phenolic antioxidant and the amine antioxidant are mixed so that the total content is 1.5% by mass or more, the weight ratio (N / O) of nitrogen (N) content of the amine antioxidant and the oxygen (O) content of the phenolic antioxidant is from 0.20 to 0.35, and particularly preferably from 0.25 to 0.30. The total antioxidant content is preferably 1.5% by mass or more, and so

Particularly preferred from 1.5 to 3% by mass. If the total antioxidant content is less than 1.5% by mass, the desired high temperature oxidation stability may not be obtained (for example, a viscosity increase rate of the Sequence III G test of 150% or less, and particularly preferably from 0 to 100%). If the proportion of the nitrogen content of the amine antioxidant and the oxygen content of the phenolic antioxidant is less than 0.20, it may be that the oxidation stability at temperature is not obtained

35 high desired. If the nitrogen content ratio of the amine antioxidant and the oxygen content of the phenolic antioxidant exceeds 0.35, the desired low friction life may not be obtained due to MoDTC.

Optionally, additives can be added to the engine oil according to the present invention such as

40 detergents, such as zinc alkyldithiophosphate (ZnDTP), sulfonates, phenates and salicylates of metals such as Ca, Mg, Ba and Na, dispersants that do not contain ashes such as alkylsuccinimide, viscosity index improvers, pour point depressants, metal deactivators, corrosion preservatives and foam antiforming agents.

Examples

In the following, the present invention is described in detail by means of the examples. As a base oil, a mineral based oil was used (kinematic viscosity: 20.3 mm2 / s (40 ° C), 4.34 mm2 / s (100 ° C); viscosity index: 124) obtained by subjecting wax hydroelination an oil produced by hydrocracking a heavy oil.

A phenolic antioxidant A, an amine B antioxidant, MoDTC, and another additive described below were mixed with the base oil in the proportion shown in Table 1 to prepare the motor oils of Example 1 and Comparative Examples 1 to 3. Table 1 also shows the proportion (mass: N / O) of nitrogen content

(N) of the amine antioxidant with respect to oxygen content (O) of the phenolic antioxidant and Mo content.

The other additive was the additive mixture containing zinc alkyl dithiophosphate (ZnDTP), calcium sulphonate, alkylsuccinimide, a viscosity index improver, a pour point depressant and a foam antiforming agent. The additive was added in an amount equal to the example and the comparative examples.

As a phenolic antioxidant A, a phenolic antioxidant (oxygen content: 12.3% by mass) shown by means of the general formula (2) in which the R5 substituent was an octyl group was used.

As the amine B antioxidant, the amine antioxidant (nitrogen content: 4.5% by mass) was used, which is a reaction product of N-phenyl-becencamine and 2,4,4-trimethylpentene.

As MoDTC, the compound shown by the general formula (1) in which R1 to R4 was a mixture of a 2-ethylhexyl group and an isotridecyl group was used and the ratio of oxygen atom / sulfur atom was 1/1

[Table 1]

Example

Comparative Example

one

one

2 3

Base oil

% by mass 84.06 84.71 83.76 84.45

Additive

% by mass 15.94 15.29 16.24 15.55

Antioxidant

% by mass 1.75 1.1 2.05 1.75

(A) phenolic

% by mass 1.0 1.1 0.8 1.0

(B) amine

% by mass 0.75 - 1.25 0.75

MoDTC

% by mass 1.44 1.44 1.44 1.05

Molybdenum (Mo)

% by mass 0.065 0.065 0.065 0.047

Other additives

% by mass 12.75 12.75 12.75 12.75

Proportion (N / O) of N content in the amine antioxidant with respect to O content in the phenol antioxidant

(mass) 0.27 0 0.58 0.27

The engine oils of the example and the comparative examples shown in Table 1 were subjected to a Sequence III G test to evaluate the performance of the engine oil. The test includes a point of evaluation of oxidation stability at elevated temperature by means of the viscosity increase rate. The viscosity increase rate of 150% or less is defined as an acceptable level (see Suzuki, Latest

35 Trend of Gasoline Engine Oil Standard, Monthly Tribology, 2003, 5, page 17). Each engine oil submitted to the Sequence III G test was compared with the engine oil corresponding to the start time of the engine test (0 hours) to determine the viscosity of the increase rate. Results are shown in table 2.

The engine oils shown in Table 1 were subjected to an engine test (a durability test in

40 bench on a chassis dynamometer) and an SRV friction test under the following conditions to determine the test time at which the friction coefficient of the engine oil was made of 0.070. The sustainability of fuel-saving efficiency was evaluated compared to a standard oil (test time at which the friction coefficient was made of 0.070: 165 hours, driving distance corresponding to this time:

10,000 km) The results are shown in the lower part of Table 2 as sustainable life of low friction (km).

Engine test conditions

Engine: 2-liter inline six-cylinder petrol engine Oil container capacity: reduced from 3.4 liters to 2 liters (test intensity increased)

5 Oil temperature in the oil container: 100 ºC Test mode: AMA travel mode (repeat) Oil sampling: every 24 hours (SRV friction test sample)

SRV friction test conditions

10 Contact conditions: cylinder on block Sliding conditions: load: 400 N; frequency: 50 Hz; amplitude: 1.5 mm; and temperature: 120 ° C.

15 The test time at which the friction coefficient of the engine oil was made of 0.070 was determined by interpolation of the sampling times of the two intercalated samples, the friction coefficient being 0.070 of the sample (oil motor) taken every 24 hours. The low friction sustainable life (driving distance, km) was determined based on the resulting test time at which the friction coefficient of the engine oil was 0.070, the test time (165 hours) at which the friction coefficient of the standard oil is

20 made 0.070, and driving distance (10,000 km).

[Table 2]

Example

Comparative Example

one

one

2 3

Rate of viscosity increase in sequence test.

% 83 270 88 120

Sustainable low-friction life MoDTC

km 10000 11000 8000 7000

As evident from the above results, the engine oil composition shown as

25 example by mixing the mineral oil and / or the synthetic base oil, the amine antioxidant and the phenolic antioxidant in an amount of 1.5% by mass or more in total and the mass proportion (N / O) of content of nitrogen (N) of the amine antioxidant with respect to oxygen content (O) of the phenolic antioxidant from 0.20 to 0.35, and MoDTC in an amount of 0.055% by mass or more as Mo element content, exhibited a Reduced viscosity increase rate of the Sequence III test of 83%, making it possible to expect a

30 excellent stability against high temperature oxidation. In addition, because the MoDTC low friction sustainable life calculated from the SRV friction test of the oil used in the engine durability test was as high as 9000 km or more, it is known that the engine oil composition exhibited a Excellent fuel saving sustainability.

The motor oil composition of Comparative Example 1 on which the phenolic antioxidant was added exhibited a long sustainable life of low friction, but showed a high rate of viscosity increase and, thus, could exhibit a lower stability against to oxidation at elevated temperature. The engine oil composition of Comparative Example 2 in which the mass ratio of the nitrogen content of the amine antioxidant to the oxygen content of the phenolic antioxidant was high, exhibited excellent

40 stability against oxidation at elevated temperature, but showed a lower life of low friction. The engine oil composition of Comparative Example 3 in which the amount of MoDTC was reduced showed a high rate of viscosity increase and lower stability against high temperature oxidation, compared to Example 1, and exhibited a life Low friction bottom.

Claims (3)

1. A long-lasting engine oil composition that saves fuel comprising: a mineral oil and / or a synthetic base oil; an amine antioxidant consisting of diphenylamine and / or phenylnaphthylamine, as shown by the following general formula (4) or (5), in which each R6, R7, R8 and R9 can be a hydrocarbon group having 3 to 20 carbon atoms and a phenolic antioxidant shown by means of the following general formula (2): in which R5 is a hydrocarbon group having 3 to 20 carbon atoms, in an amount of 1.2% by mass or more in total and the proportion (mass: N / O) of nitrogen content being (N) of the amine antioxidant with respect to oxygen content (O) of the phenolic antioxidant from 0.20 to 0.50; Y 20 molybdenum dithiocarbamate (MoDTC) in an amount of 0.055% by mass or more as a molybdenum element (Mo). 2. The composition according to claim 1, wherein the proportion (mass: N / O) of nitrogen content (N) of the amine antioxidant with respect to (O) content of phenolic antioxidant is from 0.20 to 0.35. 25 3. The composition according to claim 1, wherein the total amine antioxidant and phenolic antioxidant content is 1.5% by mass or more, the proportion (mass: N / O) of nitrogen content (N ) of the amine antioxidant with respect to oxygen content (O) of the phenolic antioxidant is 0.20 to 0.35 and the content of molybdenum dithiocarbamate (MoDTC) is 0.055% by mass or more as molybdenum element 30 (Mo).