CN111801407A - Lubricating oil composition - Google Patents

Abstract

A lubricating oil composition comprising a base oil (A) and a viscosity index improver (B) having an X-ray small angle scattering spectrum measured at 40°C and 100°C of the viscosity index improver (B) was prepared , in the range of 0.1 nm ^-1 to 1 nm ^-1 , which is the scattering vector q of the x-axis, the absolute value of the slope of the straight line calculated by the least squares method, that is, Δ|α(40)| and Δ|α(100) The ratio of |[Δ|α(40)|/Δ|α(100)|] is 1.5 or more.

Description

Lubricating oil composition

technical field

The present invention relates to lubricating oil compositions.

Background technique

In recent years, there has been a strong demand for reducing fuel consumption of vehicles such as automobiles for the purpose of effectively utilizing petroleum resources and reducing carbon dioxide emissions. For this reason, there has also been an increased demand for fuel economy of lubricating oil compositions used in engines of vehicles such as automobiles.

For example, Patent Document 1 discloses a lubricating oil composition for an internal combustion engine comprising an ashless dispersant and a viscosity index improver having a permanent shear stability index (PSSI) of 10 to 100 in a lubricating oil base oil, and a metal-based At least one of a detergent, an antioxidant, an antiwear agent, and a friction modifier, and the ratio of the viscosity index of the composition to the high temperature high shear viscosity (HTHS viscosity) at 100° C. is 32 or more.

According to Patent Document 1, this lubricating oil composition is believed to be excellent in fuel economy, further sludge suppression, and engine detergency.

prior art literature

Patent Literature

Patent Document 1: Japanese Patent Laid-Open No. 2007-217494.

SUMMARY OF THE INVENTION

The problem to be solved by the invention

For example, an engine mounted on a vehicle such as a general automobile reaches a very high temperature during high-speed operation, and the engine oil also rises to nearly 100°C. Conversely, the temperature of the engine oil in the practical area of the engine is about 80°C.

In addition, the engine oil used in a hybrid vehicle is heated to a high temperature when the engine starts, but when the motor is operated, the engine becomes low speed and reaches a low temperature of about 40 to 50°C.

That is, depending on the type and operating conditions of the engine, when the engine oil reaches a low temperature of about 40°C, it may reach a high temperature of about 100°C. Even in such a wide temperature range, engine oil excellent in fuel efficiency is required.

In Patent Document 1, from such a viewpoint, the fuel saving performance of the lubricating oil composition for an internal combustion engine described in this document has not been studied. There is still room for further improvement in perspective.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a lubricating oil composition that can stably exhibit excellent fuel efficiency even in use in a wide temperature environment ranging from a low temperature range to a high temperature range.

means of solving problems

The inventors of the present invention found that a lubricating oil composition containing a viscosity index improver that satisfies specific parameters and shows a large structural change in oil due to temperature, together with a base oil, can solve the above problems.

That is, the present invention provides the following [1].

[1] A lubricating oil composition comprising a base oil (A) and a viscosity index improver (B), the viscosity index improver (B) having a The ratio of |α(40)| to Δ|α(100)| [Δ|α(40)|/Δ|α(100)|] is above 1.5,

Operation (i): Prepare a sample oil obtained by dissolving the viscosity index improver (B) in mineral oil, perform X-ray small-angle scattering measurement at each temperature of 40°C and 100°C, and obtain the X-ray small angle Scattering spectrum (x-axis: scattering vector q(nm ^-1 ), y-axis; commonly used log(I) of scattering intensity I);

Operation (ii): In the X-ray small-angle scattering spectrum at 40°C obtained in operation (i), in the range of 0.1 nm ^-1 to 1 nm ^-1 which is the scattering vector q of the x-axis, by the least squares method, Calculate the absolute value of the slope of the straight line Δ|α(40)|;

Operation (iii): In the X-ray small-angle scattering spectrum at 100°C obtained in operation (i), in the range of 0.1 nm ^-1 to 1 nm ^-1 which is the scattering vector q of the x-axis, by the least squares method, The absolute value Δ|α(100)| of the slope of the straight line is calculated.

effect of invention

The lubricating oil composition of the present invention can stably exhibit excellent fuel efficiency even when used in a wide temperature environment ranging from a low temperature range to a high temperature range.

Detailed ways

In this specification, kinematic viscosity and viscosity index refer to values measured in accordance with JIS K2283:2000.

In this specification, the weight average molecular weight (Mw) and the number average molecular weight (Mn) of each component are values in terms of standard polystyrene measured by gel permeation chromatography (GPC). The value measured by the method described.

In the present specification, for example, "alkyl (meth)acrylate" refers to a term used to represent both "alkyl acrylate" and "alkyl methacrylate", and the same symbols are used for other similar terms. .

[lubricating oil composition]

The lubricating oil composition of the present invention contains a base oil (A) and a viscosity index improver (B) whose Δ|α calculated by the following operations (i) to (iii) The ratio of (40)| to Δ|α(100)| [Δ|α(40)|/Δ|α(100)|] reaches 1.5 or more,

Operation (i): Prepare a sample oil obtained by dissolving the viscosity index improver (B) in mineral oil, perform X-ray small-angle scattering measurement at each temperature of 40°C and 100°C, and obtain the X-ray small angle Scattering spectrum (x-axis: scattering vector q(nm ^-1 ), y-axis; common logarithm of scattering intensity I(q) log(I(q)));

Operation (ii): In the X-ray small-angle scattering spectrum at 40°C obtained in operation (i), in the range of 0.1 nm ^-1 to 1 nm ^-1 which is the scattering vector q of the x-axis, by the least squares method, Calculate the absolute value of the slope of the straight line Δ|α(40)|;

Operation (iii): In the X-ray small-angle scattering spectrum at 100°C obtained in operation (i), in the range of 0.1 nm ^-1 to 1 nm ^-1 which is the scattering vector q of the x-axis, by the least squares method, The absolute value Δ|α(100)| of the slope of the straight line is calculated.

In addition, the specific method of the said operation (i)-(iii) is described in the Example mentioned later.

In addition, the base oil (A) contained in the lubricating oil composition of the present invention and the mineral oil used for preparing the sample oil in the above-mentioned operation (i) may be the same or different.

That is, the base oil (A) contained in the lubricating oil composition of the present invention is not limited to the mineral oil used for preparing the sample oil in the above-mentioned operation (i).

The values of Δ|α(40)| and Δ|α(100)| calculated through operations (i) to (iii) are numerical values representing the improvement of the viscosity index dispersed in the sample oil at 40°C and 100°C value of the shape of agent (B).

As the values of Δ|α(40)| and Δ|α(100)| are smaller, the polymer chains constituting the viscosity index improver (B) are dispersed and dissolved in the base oil to form thin rods or thin discs. widened shape.

When the viscosity index improver (B) has a widened shape such as a thin rod shape or a thin disk shape, the viscosity index improver (B) is widely dispersed in the sample oil, so it can be considered that the sample oil The viscosity of the oil increases.

On the other hand, as the values of Δ|α(40)| and Δ|α(100)| are larger, the viscosity index improver (B) is aggregated into a spherical shape at the nanometer level.

When the viscosity index improver (B) is aggregated into a spherical shape, dispersion of the viscosity index improver (B) in the sample oil is suppressed, so it is considered that the viscosity of the sample oil decreases.

However, the viscosity index improver is blended in order to impart a viscosity-increasing effect to the lubricating oil composition.

In addition, a desired property of the viscosity index improver is that in a high temperature region where the viscosity of the base oil decreases, the effect of increasing the viscosity is required to be sufficiently exhibited, and on the other hand, in a low temperature region where the viscosity of the base oil increases, the viscosity of the lubricating oil composition is increased. If it does not increase excessively, the viscosity increase is suppressed to some extent.

That is, since the viscosity index improver is expected to be dispersed in a wide range in the base oil in the high temperature region, Δ|α obtained by numerically quantifying the shape of the viscosity index improver (B) at 100° C. in the high temperature region The smaller the value of (100)| is, the more preferable it is.

On the other hand, the desired property of the viscosity index improver is that the viscosity increase of the lubricating oil composition is suppressed to some extent so that the viscosity of the lubricating oil composition does not increase excessively in the low temperature region, so that the viscosity index at 40°C in the low temperature region is improved. The larger the value of Δ|α(40)| obtained by quantifying the shape of the agent, the better.

Also, the ratio of Δ|α(40)| to Δ|α(100)| [Δ|α(40)|/Δ|α(100)|] for the viscosity index improver (B) dispersed in the sample oil ) can also be said to be a parameter indicating the degree of the difference between the shapes at 40°C and 100°C.

That is, the viscosity index improver having a larger ratio [Δ|α(40)|/Δ|α(100)|] can be said to have high temperature dependence, and it can be said that the lubricating oil composition can be changed by changing the shape for each temperature. The viscosity is kept in an appropriate range.

In addition, it is preferable that the lubricating oil composition concerning one aspect of this invention further contains an organic molybdenum compound (C).

In addition, the lubricating oil composition of one embodiment of the present invention may further contain additives for lubricating oil other than the viscosity index improver (B) within a range that does not impair the effects of the present invention.

In the lubricating oil composition according to one embodiment of the present invention, the total content of the components (A) and (B) is preferably 60 to 100 mass % based on the total amount (100 mass %) of the lubricating oil composition. , more preferably 70 to 100 mass %, still more preferably 80 to 100 mass %, still more preferably 85 to 100 mass %.

Hereinafter, the details of each component contained in the lubricating oil composition of one embodiment of the present invention will be described.

＜Base oil (A)＞

The base oil (A) contained in the lubricating oil composition of one embodiment of the present invention may be a mineral oil, a synthetic oil, or a mixed oil of a mineral oil and a synthetic oil.

Examples of the mineral oil include atmospheric residues obtained by subjecting crude oil such as paraffinic crude oil, intermediate crude oil, and naphthenic crude oil to atmospheric distillation; these atmospheric residues are obtained by subjecting these atmospheric residues to vacuum distillation. The distillate oil; the mineral oil obtained by applying one or more kinds of refining treatments such as solvent deasphalting, solvent extraction, hydrocracking, solvent dewaxing, catalytic dewaxing, and hydrorefining to the distillate oil; Mineral oil (GTL) etc. obtained by isomerizing a wax (GTL wax (Gas To Liquids WAX)) produced by a Fischer-Tropsch process or the like.

These mineral oils may be used alone or in combination of two or more.

Examples of synthetic oils include polyα-olefins such as α-olefin homopolymers and α-olefin copolymers (eg, α-olefin copolymers having 8 to 14 carbon atoms such as ethylene-α-olefin copolymers); Isoparaffins; dibasic acid esters (such as ditridecyl glutarate, etc.), polyol esters, dibasic acid esters, aromatic esters (such as 2-ethylhexyl trimellitate, homo Various esters such as 2-ethylhexyl pyromellitic acid) and phosphoric acid ester; various ethers such as polyalkylene glycol and polyphenyl ether; alkylbenzene; alkylnaphthalene, etc.

These synthetic oils may be used alone or in combination of two or more.

From the viewpoint of improving the dispersibility of the viscosity index improver (B), the base oil (A) used in one embodiment of the present invention preferably contains a mineral oil.

The mineral oil is preferably a mineral oil classified into Class 2 or 3 in the base oil category of API (American Petroleum Institute), and more preferably a mineral oil classified into Class 3.

In the base oil (A) used in one embodiment of the present invention, the content of the mineral oil is preferably 50 to 100% by mass, and more preferably 50 to 100% by mass based on the total amount (100% by mass) of the base oil (A). 65-100 mass %, More preferably, it is 80-100 mass %, More preferably, it is 90-100 mass %.

The kinematic viscosity at 40°C of the base oil (A) used in one embodiment of the present invention is preferably 5 to 80 mm ² /s, more preferably 10 to 60 mm ² /s, and even more preferably 12 to 40 mm ² /s , and more preferably 14 to 30 mm ² /s.

The kinematic viscosity at 100° C. of the base oil (A) used in one embodiment of the present invention is preferably 1.0 to 7.0 mm ² /s, more preferably 2.0 to 6.0 mm ² /s, and even more preferably 3.0 to 5.0 mm ² /s, more preferably 3.5 to 4.5 mm ² /s.

In addition, the viscosity index of the base oil (A) used in one embodiment of the present invention is preferably 80 or more, more preferably 80 or more, from the viewpoint of improving fuel economy while suppressing viscosity changes due to temperature changes. It is 100 or more, more preferably 110 or more, still more preferably 120 or more.

In the lubricating oil composition of one embodiment of the present invention, when a mixed oil in which two or more base oils are combined is used, the kinematic viscosity and viscosity index of the mixed oil are preferably within the above-mentioned ranges.

In the lubricating oil composition of one embodiment of the present invention, the content of the base oil (A) is preferably 55 mass % or more, and more preferably 60 mass % based on the total amount (100 mass %) of the lubricating oil composition. The above, more preferably 65 mass % or more, still more preferably 70 mass % or more, and preferably 99.5 mass % or less, more preferably 99 mass % or less, and still more preferably 95 mass % or less.

<Viscosity Index Improver (B)>

The lubricating oil composition of the present invention contains the ratio [Δ|α(40)|/Δ|α of Δ|α(40)| to Δ|α(100)| calculated through the aforementioned operations (i) to (iii). (100)|] The viscosity index improver (B) of 1.5 or more.

In the case where the aforementioned ratio [Δ|α(40)|/Δ|α(100)|] of the viscosity index improver (B) is less than 1.5, the degree of change in shape per temperature is small, and it is difficult to adjust to the lubricating oil Appropriate viscosity according to the temperature of the composition also causes a reduction in fuel efficiency.

On the other hand, by making the lubricating oil composition containing the viscosity index improver (B) in the aforementioned ratio [Δ|α(40)|/Δ|α(100)|] of 1.5 or more, even in the low temperature region to the high temperature Even in use in a wide temperature environment in a region, the viscosity can be kept in an appropriate range, so that excellent fuel economy can be stably exhibited.

From the above viewpoints, in the lubricating oil composition of one embodiment of the present invention, the aforementioned ratio [Δ|α(40)|/Δ|α(100)|] as the viscosity index improver (B) is preferably 1.55 or more , more preferably 1.58 or more, still more preferably 1.6 or more, still more preferably 1.65 or more, furthermore preferably 1.7 or more, still more preferably 1.8 or more.

The value of Δ|α(40)| of the viscosity index improver (B) used in one embodiment of the present invention can be determined to some extent so that the viscosity of the lubricating oil composition does not increase excessively in a low temperature region. From the viewpoint of a viscosity index improver that suppresses an increase in viscosity, it is preferably 2.3 (1/(nm ^-1 )) or more, more preferably 2.5 (1/(nm ^-1 )) or more, and still more preferably 2.8 (1/( nm ^-1 )) or more, more preferably 3.2(1/(nm ^-1 )) or more, and more preferably 6.0(1/(nm ^-1 )) or less.

The value of Δ|α(100)| of the viscosity index improver (B) used in one embodiment of the present invention can sufficiently exhibit the value of Δ|α(100)| in the base oil in a high-temperature region in a widely dispersed state. From the viewpoint of the viscosity index improver having the effect of increasing viscosity, it is preferably 3.5 (1/(nm ^-1 )) or less, more preferably 3.2 (1/(nm ^-1 )) or less, and still more preferably 3.0 (1/( nm ^-1 )) or less, more preferably 2.7(1/(nm ^-1 )) or less, and more preferably 1.2(1/(nm ^-1 )) or more.

In one embodiment of the present invention, the viscosity index improver (B) may be composed of one type of polymer or two or more types of polymers.

When the viscosity index improver (B) consists of two or more kinds of polymers, the aforementioned ratios of the respective polymers [Δ|α(40)|/Δ|α(100)|], Δ|α(40 The value of )| and the value of Δ|α(100)| may fall within the above-mentioned range.

In addition, among two or more kinds of polymers, the aforementioned ratios [Δ|α(40)|/Δ|α(100)|], the value of Δ|α(40)|, and the Δ|α The value of (100)| is outside the above-mentioned range, but the whole of the viscosity index improver (B) including other polymers should just fall within the above-mentioned range.

In the lubricating oil composition of one embodiment of the present invention, from the viewpoint of making a lubricating oil composition that can stably exhibit excellent fuel efficiency even in use in a wide temperature environment ranging from a low temperature range to a high temperature range The content of the viscosity index improver (B) in terms of resin components is based on the total amount (100% by mass) of the lubricating oil composition, preferably 0.5 to 8.0% by mass, more preferably 0.7 to 5.0% by mass %, more preferably 1.0 to 4.0 mass %, still more preferably 1.0 to 3.5 mass %.

In the viscosity index improver (B), the resin component constituting the viscosity index improver is often a solution dissolved in a diluent oil such as mineral oil and synthetic oil in consideration of handling properties and solubility with the base oil (A). commercially available form.

In this specification, the above-mentioned "content in terms of resin component of the viscosity index improver (B)" refers to the content of the resin component constituting the viscosity index improver, excluding the mass of the diluent oil.

In addition, the above-mentioned "resin component" refers to a polymer having a weight average molecular weight (Mw) of 1000 or more and a certain repeating unit.

In the lubricating oil composition according to one embodiment of the present invention, the weight average molecular weight (Mw) of the viscosity index improver (B) can be stably excellent even when used in a wide temperature environment ranging from a low temperature range to a high temperature range. From the viewpoint of a fuel-efficient lubricating oil composition, it is preferably 100,000 to 900,000, more preferably 200,000 to 800,000, still more preferably 300,000 to 750,000, still more preferably 350,000 to 700,000.

In addition, from the same viewpoint as above, as the molecular weight distribution (Mw/Mn) of the viscosity index improver (B) (wherein, Mw represents the weight average molecular weight of the viscosity index improver (B), and Mn represents the viscosity index improver ( The number average molecular weight of B) is preferably 6.00 or less, more preferably 3.00 or less, still more preferably 2.00 or less, still more preferably 1.95 or less, and more preferably 1.90 or less.

In addition, as the molecular weight distribution of the viscosity index improver (B) is small, the fuel efficiency of the lubricating oil composition contained with the base oil (A) tends to be improved.

Further, the molecular weight distribution (Mw/Mn) of the viscosity index improver (B) is not particularly limited as a lower limit value, but is usually 1.05 or more, preferably 1.10 or more, and more preferably 1.15 or more.

However, the aforementioned ratios of the viscosity index improver (B) [Δ|α(40)|/Δ|α(100)|], the value of Δ|α(40)|, and the value of Δ|α(100)| It can be prepared according to the kind and content of the structural unit of the polymer constituting the viscosity index improver (B), and the structure of the polymer.

For example, the viscosity index improver (B) preferably contains a polymer (B1) having a structural unit (β1) derived from a monomer selected from butadiene and hydrogenated butadiene.

In the viscosity index improver (B) containing the polymer (B1), the value of Δ|α(40)| tends to become large, while the value of Δ|α(100)| [Δ|α(40)|/Δ|α(100)|] is made large.

From the above viewpoints, in the polymer (B1) used in one embodiment of the present invention, the content of the structural unit (β1) is preferably 100 mol % relative to the total amount (100 mol %) of the structural units of the polymer (B1). 0.1-70 mol%, More preferably, it is 0.3-60 mol%, More preferably, it is 0.5-50 mol%.

Furthermore, the polymer (B1) more preferably contains the structural unit (β2) derived from the hydroxyl group-containing vinyl monomer together with the structural unit (β1).

In the polymer (B1) used in one embodiment of the present invention, the content of the structural unit (β2) is preferably 0.1 to 30 mol % with respect to the total amount (100 mol %) of the structural units of the polymer (B1). , more preferably 0.5 to 20 mol %, still more preferably 1.0 to 15 mol %, still more preferably 1.5 to 10 mol %.

In addition, as a hydroxyl-containing vinyl monomer, it will be mentioned later.

The content of the polymer (B1) in the viscosity index improver (B) used in one embodiment of the present invention is preferably 70 to 70% based on the total amount (100% by mass) of the viscosity index improver (B). 100 mass %, more preferably 80 to 100 mass %, still more preferably 90 to 100 mass %, still more preferably 95 to 100 mass %.

As the polymer (B1) used as the viscosity index improver (B) in one embodiment of the present invention, the aforementioned ratio [Δ|α(40)|/Δ|α(100)|] is adjusted to the above-mentioned range. From a viewpoint, it is preferable that it is 1 or more types chosen from a styrene-isoprene-butadiene copolymer (B11) and a comb polymer (B12).

Hereinafter, with respect to the components (B11) and (B12), a suitable aspect will be described from the viewpoint of adjusting the aforementioned ratio [Δ|α(40)|/Δ|α(100)|] to the above-mentioned range.

<Styrene-isoprene-butadiene copolymer (B11)>

The styrene-isoprene-butadiene copolymer (B11) used in one embodiment of the present invention may be a copolymer each having a structural unit derived from styrene, isoprene, and butadiene.

In addition, in the styrene-isoprene-butadiene copolymer (B11), a part or all of the structural units derived from butadiene may be replaced with structural units derived from hydrogenated butadiene. unit.

Moreover, as a form of the copolymer of a component (B11), a block copolymer may be sufficient, and a random copolymer may be sufficient as it.

The suitable ranges of the weight average molecular weight (Mw) and molecular weight distribution (Mw/Mn) of the component (B11) are the same as the suitable ranges specified as the above-mentioned component (B).

In the component (B11), as the content of the structural unit (β1) derived from a monomer selected from butadiene and hydrogenated butadiene, relative to the total amount (100 mol %) of the structural unit of the component (B11), Preferably it is 2.5-30 mol%, More preferably, it is 3.0-25 mol%, More preferably, it is 3.5-20 mol%, More preferably, it is 4.0-15 mol%.

In the component (B11), the content of the structural unit (p1) derived from styrene is preferably 1 to 50 mol %, more preferably 3 mol % relative to the total amount (100 mol %) of the structural unit of the component (B11). ~40 mol%, more preferably 5 to 30 mol%, still more preferably 7 to 25 mol%.

In the component (B11), the content (p2) of the structural unit derived from isoprene is preferably 10 to 95 mol % with respect to the total amount (100 mol %) of the structural unit of the component (B11), more preferably It is 25-90 mol%, More preferably, it is 40-85 mol%, More preferably, it is 55-80 mol%.

In addition, the component (B11) may have a structural unit derived from a monomer other than styrene, isoprene, and butadiene (hydrogenated butadiene is also included).

However, in the component (B11), the total content of the structural units (β1), (p1) and (p2) is preferably 80 to 100 mol %, More preferably, it is 85-100 mol%, More preferably, it is 90-100 mol%, More preferably, it is 95-100 mol%.

<Comb polymer (B12)>

In the present specification, a comb polymer refers to a polymer having a structure in which the main chain has a plurality of trifurcated branch points extending from a high-molecular-weight side chain.

The comb polymer (B12) used in the present invention is preferably a polymer having a structural unit (X1) derived from a macromonomer (x1) having a structural unit (X1) derived from a A high molecular weight monomer of the structural unit (β1) of the monomer in diene and hydrogenated butadiene.

That is, the macromonomer (x1) which the comb polymer (B12) has belongs to the above-mentioned "high molecular weight side chain".

In addition, in this invention, the said "macromonomer" means the high molecular weight monomer which has a polymerizable functional group, Preferably it is a high molecular weight monomer which has a polymerizable functional group at the terminal.

Comb polymers with longer side chains are easier to disperse in a wide range in a high temperature region, and more likely to aggregate in a low temperature region, so the aforementioned ratio [Δ|α(40)|/Δ|α(100)| ] is easier to increase.

That is, the larger the molecular weight of the macromonomer (x1) of the comb polymer (B12), the easier it is to adjust the aforementioned ratio [Δ|α(40)|/Δ|α(100)|] to a larger value .

In particular, the macromonomer (x1) possessed by the comb polymer (B12) is a high molecular weight monomer having a structural unit (β1) derived from a monomer selected from butadiene and hydrogenated butadiene, Thereby, the aforementioned ratio [Δ|α(40)|/Δ|α(100)|] can be easily adjusted to a larger value.

The number average molecular weight (Mn) of the macromonomer (x1) is preferably 300 or more, more preferably 500 or more, still more preferably 1,000 or more, still more preferably 2,000 or more, and furthermore, it should be noted that the number average molecular weight (Mn) of the macromonomer (x1) It is 3,000 or more, preferably 4,000 or more for one layer, and preferably 100,000 or less, more preferably 50,000 or less, still more preferably 20,000 or less, and still more preferably 10,000 or less.

From the above viewpoint, in the comb polymer (B12) used in one embodiment of the present invention, the content of the structural unit (X1) is the total amount (100 mol %) of the structural units of the comb polymer (B12) On a basis, it is preferably 0.1 to 20 mol %, more preferably 0.3 to 10 mol %, and further preferably 0.5 to 5 mol %.

Examples of the polymerizable functional group of the macromonomer (x1) include acryloyl (CH ₂ =CH-COO-), methacryloyl (CH ₂ =CCH ₃ -COO-), vinyl (CH 2 ), and vinyl (CH 2 ). ₂ =CH-), vinyl ether (CH ₂ =CH-O-), allyl (CH ₂ =CH-CH ₂ -), allyl ether (CH ₂ =CH-CH ₂ -O- ), a group represented by CH ₂ =CH-CONH-, a group represented by CH ₂ =CCH ₃ -CONH-, and the like.

As content of the structural unit (β1) derived from a monomer selected from butadiene and hydrogenated butadiene in the macromonomer (x1), relative to the total amount of structural units of the macromonomer (x1) (100 mol %), preferably 0.5 to 100 mol %, more preferably 1 to 100 mol %, still more preferably 1 to 50 mol %, still more preferably 1 to 20 mol %, still more preferably 1 to 5 mol % %.

The macromonomer (x1) may have, for example, one or more repeating units represented by the following general formulae (i) to (iii) in addition to the structural unit (β1).

In addition, when a macromonomer (x1) is a copolymer, a block copolymer may be sufficient as a form of copolymerization, and a random copolymer may be sufficient as it.

[hua 1]

In the above-mentioned general formula (i), R ^b1 represents a linear or branched alkylene group having 1 to 10 carbon atoms, and specifically, methylene, ethylene, and 1,2-propylene can be mentioned. , 1,3-propylene, pentylene, hexylene, heptylene, octylene, nonylene, decylene, and 2-ethylhexylene, etc.

In the above general formula (ii), R ^b2 represents a linear or branched alkylene group having 2 to 4 carbon atoms, and specifically, ethylene, 1,2-propylene, 1,3 - Propylene, 1,2-butylene, 1,3-butylene, and 1,4-butylene, etc.

In the above general formula (iii), R ^b3 represents a hydrogen atom or a methyl group.

In addition, R ^b4 represents a linear or branched alkyl group having 1 to 10 carbon atoms, and specifically, methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, n- Heptyl, n-octyl, n-nonyl, n-decyl, isopropyl, isobutyl, sec-butyl, tert-butyl, isopentyl, tert-amyl, isohexyl, tert-hexyl, isoheptyl, tert- Heptyl, 2-ethylhexyl, isooctyl, isononyl, and isodecyl, and the like.

In addition, when each has two or more repeating units represented by said general formula (i)-(iii), R ^b1 , R ^b2 , R ^b3 , and R ^b4 may be the same or different from each other.

The comb polymer (B12) used in one embodiment of the present invention may be a homopolymer composed of a structural unit (X1) derived from only one type of macromonomer (x1), or may be a homopolymer containing two types of macromonomers (x1). A copolymer of the structural unit (X1) of the above macromonomer (x1).

In addition, the comb polymer (B12) used in one embodiment of the present invention may contain a structural unit derived from a macromonomer (x1) and a structure derived from other than the macromonomer (x1). A copolymer of structural units (X2) of other monomers (x2).

As a specific structure of such a comb polymer, it is preferable to have a structural unit (X1) derived from a macromonomer (x1) with respect to a main chain containing a structural unit (X2) derived from a monomer (x2). ) side chain copolymer.

Examples of the monomer (x2) include monomers (x2-a) represented by the following general formula (a1), alkyl (meth)acrylates (x2-b), and vinyl monomers containing nitrogen atoms. body (x2-c), hydroxyl-containing vinyl monomer (x2-d), aliphatic hydrocarbon vinyl monomer (x2-e), alicyclic hydrocarbon vinyl monomer (x2-f), ethylene Base esters (x2-g), vinyl ethers (x2-h), vinyl ketones (x2-i), epoxy-containing vinyl monomers (x2-j), halogen-containing vinyl Monomers (x2-k), esters of unsaturated polycarboxylic acids (x2-l), (di)alkyl fumarate (x2-m), and (x2-n) alkyl maleate )Wait.

The monomer (x2) preferably contains a monomer (x2-a) represented by the following general formula (a1), an alkyl (meth)acrylate (x2-b), and a hydroxyl group-containing vinyl monomer One or more of the bodies (x2-d), more preferably at least a hydroxyl group-containing vinyl monomer (x2-d).

The hydroxyl group-containing vinyl monomer (x2-d) becomes a constituent monomer of the above-mentioned structural unit (β2).

In the comb polymer (B12) used in one embodiment of the present invention, the content of the structural unit (β2) derived from the hydroxyl group-containing vinyl monomer (x2-d) is calculated as the content of the comb polymer (B12). The total amount (100 mol %) of the structural units is preferably 0.1 to 30 mol %, more preferably 0.5 to 20 mol %, still more preferably 1.0 to 15 mol %, and still more preferably 1.5 to 10 mol %.

(monomer (x2-a) represented by the following general formula (a1))

[hua 2]

In the above general formula (a1), R ^b11 represents a hydrogen atom or a methyl group.

R ^b12 represents a single bond, a linear or branched alkylene group having 1 to 10 carbon atoms, -O-, or -NH-.

R ^b13 represents a linear or branched alkylene group having 2 to 4 carbon atoms. Moreover, n represents an integer of 1 or more (preferably an integer of 1 to 20, and more preferably an integer of 1 to 5). In addition, when n is an integer of 2 or more, a plurality of R ^b13 may be the same or different, and the (R ^b13 O) _n part may be a random bond or a block bond.

R ^b14 represents a linear or branched alkyl group having 1 to 60 carbon atoms (preferably 10 to 50, more preferably 20 to 40).

As the above-mentioned "linear or branched alkylene group having 1 to 10 carbon atoms", "linear or branched alkylene group having 2 to 4 carbon atoms", and "linear or branched alkylene group having 1 to 60 carbon atoms" The specific group of "straight-chain or branched alkyl" includes the same groups as those exemplified in the description related to the above-mentioned general formulae (i) to (iii).

(Alkyl (meth)acrylate (x2-b))

Examples of the alkyl (meth)acrylate (x2-b) include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, and isopropyl (meth)acrylate. Propyl, n-butyl (meth)acrylate, tert-butyl (meth)acrylate, amyl (meth)acrylate, hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, ( Heptyl (meth)acrylate, 2-tert-butylheptyl (meth)acrylate, octyl (meth)acrylate, and 3-isopropylheptyl (meth)acrylate, and the like.

As carbon number of the alkyl group which the alkyl (meth)acrylate (x2-b) has, 1-30 are preferable, 1-24 are more preferable, and 1-18 are still more preferable.

In addition, this alkyl group may be a straight-chain alkyl group, and a branched-chain alkyl group may be sufficient as it.

(nitrogen-containing vinyl monomer (x2-c))

Examples of the nitrogen atom-containing vinyl monomer (x2-c) include an amide group-containing vinyl monomer (x2-c1), a nitro group-containing monomer (x2-c2), and a primary amino group-containing vinyl monomer. base monomers (x2-c3), secondary amino-containing vinyl monomers (x2-c4), tertiary amino-containing vinyl monomers (x2-c5), and nitrile-containing vinyl monomers (x2-c6 )Wait.

Examples of the amide group-containing vinyl monomer (x2-c1) include (meth)acrylamide; N-methyl (meth)acrylamide, N-ethyl (meth)acrylamide, N- Monoalkylamino(meth)acrylamides such as isopropyl(meth)acrylamide, N-n-butyl(meth)acrylamide, and isobutyl(meth)acrylamide; N-methylaminoethyl (meth)acrylamide, N-ethylaminoethyl (meth)acrylamide, N-isopropylamino-n-butyl (meth)acrylamide, N-n-butylamino-n-butyl (methyl) ) acrylamide, isobutylamino-n-butyl(meth)acrylamide and other monoalkylaminoalkyl(meth)acrylamides; N,N-dimethyl(meth)acrylamide, N,N-dimethyacrylamide Dialkylamino(meth)acrylamides such as ethyl(meth)acrylamide, N,N-diisopropyl(meth)acrylamide, and N,N-di-n-butyl(meth)acrylamide ; N,N-Dimethylaminoethyl (meth)acrylamide, N,N-diethylaminoethyl (meth)acrylamide, N,N-dimethylaminopropyl (meth)propylene amides, and dialkylaminoalkyl (meth)acrylamides such as N,N-di-n-butylaminobutyl(meth)acrylamide; N-vinylformamide, N-vinylacetamide, N- N-vinyl carboxylic acid amides such as vinyl-n-propionyl amide, N-vinyl isopropionyl amide, and N-vinyl hydroxyacetamide, and the like.

As a nitro group-containing monomer (x2-c2), nitroethylene, 3-nitro-1-propene, etc. are mentioned, for example.

Examples of the primary amino group-containing vinyl monomer (x2-c3) include alkenylamines having alkenyl groups having 3 to 6 carbon atoms, such as (meth)allylamine and crotamine; (methyl) Aminoalkyl (meth)acrylate etc. which have a C2-C6 alkyl group, such as aminoethyl acrylate.

Examples of the secondary amino group-containing vinyl monomer (x2-c4) include (meth)acrylic monoacrylates such as tert-butylaminoethyl (meth)acrylate and methylaminoethyl (meth)acrylate. Alkylaminoalkyl esters; Dienylamines having 6 to 12 carbon atoms such as bis(meth)allylamine, etc.

Examples of the tertiary amino group-containing vinyl monomer (x2-c5) include (meth)acrylic acid such as dimethylaminoethyl (meth)acrylate and diethylaminoethyl (meth)acrylate. Dialkylaminoalkyl esters; alicyclic (meth)acrylates having a nitrogen atom such as morpholinoethyl (meth)acrylate; and their hydrochlorides, sulfates, phosphates or lower alkyl groups (1 to 8 carbon atoms) monocarboxylic acid (acetic acid, propionic acid, etc.) salt, etc.

As a nitrile group-containing vinyl monomer (x2-c6), (meth)acrylonitrile etc. are mentioned, for example.

(hydroxyl-containing vinyl monomer (x2-d))

Examples of the hydroxyl group-containing vinyl monomer (x2-d) include a hydroxyl group-containing vinyl monomer (x2-d1), a polyoxyalkylene chain-containing vinyl monomer (x2-d2), and the like .

Examples of the hydroxyl-containing vinyl monomer (x2-d1) include 2-hydroxyethyl (meth)acrylate, 2- or 3-hydroxypropyl (meth)acrylate, and the like having carbon atoms. Hydroxyalkyl (meth)acrylate of 2~6 alkyl groups; N,N-dihydroxymethyl (meth)acrylamide, N,N-dihydroxypropyl (meth)acrylamide, N,N - Mono- or dihydroxyalkyl-substituted (meth)acrylamides having an alkyl group having 1 to 4 carbon atoms, such as di-2-hydroxybutyl(meth)acrylamide; vinyl alcohol; (meth)allyl alcohol , crotyl alcohol, isocrotyl alcohol, 1-octenol and 1-undecenol and other enols with 3 to 12 carbon atoms; 1-buten-3-ol, 2-buten-1-ol and 2-butenol Butene-1,4-diol and other alkene monoalcohols or alkene diols with 4 to 12 carbon atoms; 2-hydroxyethyl propenyl ether and other alkyl groups with 1 to 6 carbon atoms and 3~ 10 alkenyl hydroxyalkyl alkenyl ethers; alkenyl, macromonomers are introduced into polyols such as glycerol, pentaerythritol, sorbitol, sorbitan, diglycerol, sugars, and sucrose (x1) Compounds containing unsaturated groups such as the above-mentioned polymerizable functional groups; alkenyl groups are introduced into glyceric acid, glycerin fatty acid esters, and the above-mentioned polymerizable functional groups that macromonomers (x1) have, etc. Compounds of unsaturated groups, etc.

Among these, a hydroxyl group-containing vinyl monomer having two or more hydroxyl groups is preferable, and a compound in which an unsaturated group is introduced into a polyhydric alcohol or glyceric acid is more preferable.

Examples of the polyoxyalkylene chain-containing vinyl monomer (x2-d2) include polyoxyalkylene glycols (the number of carbon atoms in the alkylene group is 2 to 4, the degree of polymerization is 2 to 50), polyoxyalkylene glycol Oxyalkylene polyols (polyoxyalkylene ethers of the above-mentioned polyols (the number of carbon atoms in the alkylene group is 2 to 4, and the degree of polymerization is 2 to 100)), polyoxyalkylene glycol, or polyoxyalkylene Mono(meth)acrylate of alkyl (1 to 4 carbon atoms) ether of polyhydric alcohol [polyethylene glycol (Mn: 100 to 300) mono(meth)acrylate, polypropylene glycol (Mn: 130 to 300) 500) Mono(meth)acrylate, methoxy polyethylene glycol (Mn: 110~310) (meth)acrylate, lauryl alcohol ethylene oxide adduct (2~30 mol) (methyl) Acrylate, and mono(meth)acrylic acid polyoxyethylene (Mn: 150~230) sorbitan, etc.] and so on.

(aliphatic hydrocarbon vinyl monomer (x2-e))

Examples of the aliphatic hydrocarbon-based vinyl monomer (x2-e) include ethylene, propylene, butene, isobutene, pentene, heptene, diisobutene, octene, dodecene, and octadecene. Olefins with 2 to 20 carbon atoms; butadiene, isoprene, 1,4-pentadiene, 1,6-heptadiene and 1,7-octadiene with 4 to 12 carbon atoms Alkanediene, etc.

The number of carbon atoms of the aliphatic hydrocarbon-based vinyl monomer (x2-e) is preferably 2 to 30, more preferably 2 to 20, and even more preferably 2 to 12.

(alicyclic hydrocarbon vinyl monomer (x2-f))

Examples of the alicyclic hydrocarbon-based vinyl monomer (x2-f) include cyclohexene, (di)cyclopentadiene, pinene, limonene, vinylcyclohexene, and ethylidenebicycloheptene. Wait.

As carbon number of an alicyclic hydrocarbon-based vinyl monomer (x2-f), 3-30 are preferable, 3-20 are more preferable, and 3-12 are still more preferable.

(Vinyl Esters (x2-g))

Examples of vinyl esters (x2-g) include vinyl acetate, vinyl propionate, vinyl butyrate, and vinyl esters of saturated fatty acids having 2 to 12 carbon atoms, such as vinyl acetate, vinyl propionate, and vinyl octoate.

(Vinyl ethers (x2-h))

Examples of vinyl ethers (x2-h) include carbons such as methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, and 2-ethylhexyl vinyl ether. Alkyl vinyl ethers with 1 to 12 atoms; alkoxyalkyl vinyls with 1 to 12 carbon atoms such as vinyl-2-methoxyethyl ether and vinyl-2-butoxyethyl ether base ether, etc.

(vinyl ketones (x2-i))

Examples of vinyl ketones (x2-i) include alkyl vinyl ketones having 1 to 8 carbon atoms such as methyl vinyl ketone and ethyl vinyl ketone.

(Epoxy-containing vinyl monomer (x2-j))

As an epoxy group-containing vinyl monomer (x2-j), glycidyl (meth)acrylate, glycidyl (meth)allyl ether, etc. are mentioned, for example.

(Halogen-containing vinyl monomer (x2-k))

Examples of the halogen-containing vinyl monomer (x2-k) include vinyl chloride, vinyl bromide, vinylidene chloride, and (meth)allyl chloride.

(ester of unsaturated polycarboxylic acid (x2-l))

As the ester (x2-1) of unsaturated polyhydric carboxylic acid, for example, alkyl ester of unsaturated polyhydric carboxylic acid, cycloalkyl ester of unsaturated polyhydric carboxylic acid, and aralkyl ester of unsaturated polyhydric carboxylic acid can be mentioned. etc., as an unsaturated carboxylic acid, maleic acid, fumaric acid, itaconic acid, etc. are mentioned, for example.

((di)alkyl fumarate (x2-m))

Examples of (di)alkyl fumarate (x2-m) include monomethyl fumarate, dimethyl fumarate, monoethyl fumarate, diethyl fumarate, fumarate Ethyl fumarate, monobutyl fumarate, dibutyl fumarate, dipentyl fumarate, and dihexyl fumarate, etc.

((di)alkyl maleate (x2-n))

Examples of (di)alkyl maleate (x2-n) include monomethyl maleate, dimethyl maleate, monoethyl maleate, diethyl maleate, maleic methyl ethyl ester, monobutyl maleate, and dibutyl maleate, etc.

In addition, as the monomer (x2), a phosphorus atom-containing monomer and a monomer other than an aromatic hydrocarbon-based vinyl monomer are preferable.

That is, the content of the structural unit derived from the phosphorus atom-containing monomer and the content of the structural unit derived from the aromatic hydrocarbon-based vinyl monomer are preferably as small as possible.

The content of the structural unit derived from the phosphorus atom-containing monomer is preferably less than 0.01 mol %, more preferably less than 0.001 mol % based on the total amount (100 mol %) of the structural units of the comb polymer (B12). % by mole, more preferably 0% by mole.

In addition, the phosphorus atom-containing monomer refers to a phosphorus atom-containing monomer, and specifically, phosphoric acid (meth)acryloyloxyethyl ester and phosphoric acid (meth)acryloyloxy are exemplified (Meth)acryloyloxyalkyl phosphates such as isopropyl ester; vinyl phosphate, allyl phosphate, propylene phosphate, isopropyl phosphate, butenyl phosphate, pentene phosphate, octenyl phosphate , decenyl phosphate, and alkenyl phosphates such as dodecenyl phosphate; (meth)acryloyloxyalkylphosphonic acids such as (meth)acryloyloxyethylphosphonic acid; vinylphosphonic acid , allylphosphonic acid, and alkenylphosphonic acid such as octenylphosphonic acid, etc.

The content of the structural unit derived from the aromatic hydrocarbon-based vinyl monomer is preferably less than 0.01 mol %, and more preferably as low as the total amount (100 mol %) of the structural units of the comb polymer (B12). It is 0.001 mol%, more preferably 0 mol%.

Examples of the aromatic hydrocarbon-based vinyl monomer include styrene, α-methylstyrene, α-ethylstyrene, vinyltoluene, 2,4-dimethylstyrene, and 4-ethylbenzene Ethylene, 4-isopropylstyrene, 4-butylstyrene, 4-phenylstyrene, 4-cyclohexylstyrene, 4-benzylstyrene, p-methylstyrene, monochlorostyrene, Dichlorostyrene, tribromostyrene, tetrabromostyrene, 4-crotylbenzene, indene, and 2-vinylnaphthalene, etc.

<Organo-molybdenum compound (C)>

The lubricating oil composition of one embodiment of the present invention preferably contains an organic molybdenum-based compound (C) as a friction modifier.

In the lubricating oil composition of one embodiment of the present invention, the content in terms of molybdenum atoms of the organic molybdenum-based compound (C) is preferably 400 to 1000 based on the total amount (100 mass %) of the lubricating oil composition. The mass ppm is more preferably 400 to 950 mass ppm, still more preferably 400 to 900 mass ppm, and still more preferably 400 to 850 mass ppm.

In addition, in this specification, content of a molybdenum atom means the value measured based on JPI-5S-38-92.

As the organic molybdenum compound (C) used in one embodiment of the present invention, any organic compound having a molybdenum atom can be used, and from the viewpoint of improving the friction reducing effect, it is preferably selected from molybdenum dithiophosphate (MoDTP) ) and one or more of molybdenum dithiocarbamate (MoDTC).

In addition, the organic molybdenum-based compound (C) may be used alone or in combination of two or more.

As molybdenum dithiophosphate (MoDTP), a compound represented by the following general formula (c1-1) or a compound represented by the following general formula (c1-2) is preferable.

[hua 3]

In the above general formulae (c1-1) and (c1-2), R ¹ to R ⁴ each independently represent a hydrocarbon group, and may be the same or different from each other.

X ¹ to X ⁸ each independently represent an oxygen atom or a sulfur atom, and may be the same or different from each other. However, at least two of X ¹ to X ⁸ in formula (c1-1) are sulfur atoms.

In addition, in one form of this invention, in the said general formula (c1-1), it is preferable that X ¹ and X ² are oxygen atoms, and X ³ to X ⁸ are sulfur atoms.

In the above-mentioned general formula (c1-1), from the viewpoint of improving solubility, the molar ratio [sulfur atom/oxygen atom] of sulfur atom to oxygen atom in X ¹ to X ⁸ is preferably 1/4 to 4/1, More preferably, it is 1/3 to 3/1.

In addition, in the aforementioned general formula (c1-2), X ¹ and X ² are preferably oxygen atoms, and X ³ and X ⁴ are preferably sulfur atoms.

In the above-mentioned general formula (c1-2), from the same viewpoint as above, the molar ratio [sulfur atom/oxygen atom] of sulfur atom and oxygen atom in X ¹ to X ⁴ is preferably 1/3 to 3/1, More preferably, it is 1.5/2.5 to 2.5/1.5.

The number of carbon atoms of the hydrocarbon group that can be selected as R ¹ to R ⁴ is preferably 1 to 20, more preferably 5 to 18, still more preferably 5 to 16, and still more preferably 5 to 12.

Specific examples of the hydrocarbon group that can be selected as R ¹ to R ⁴ include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, and undecyl. alkyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, and octadecyl; octenyl, nonenyl, Alkenyl such as decenyl, undecenyl, dodecenyl, tridecenyl, tetradecenyl, pentadecenyl; cyclohexyl, dimethylcyclohexyl, ethylcyclohexyl , cycloalkyl such as methylcyclohexylmethyl, cyclohexylethyl, propylcyclohexyl, butylcyclohexyl, and heptylcyclohexyl; aryl such as phenyl, naphthyl, anthracenyl, biphenyl, and terphenyl alkyl aryl groups such as tolyl, dimethylphenyl, butylphenyl, nonylphenyl, methylbenzyl, and dimethylnaphthyl; phenylmethyl, phenylethyl, and Arylalkyl such as diphenylmethyl and the like.

Examples of molybdenum dithiocarbamate (MoDTC) include dinuclear molybdenum dithiocarbamate containing two molybdenum atoms in one molecule, and trinuclear disulfide containing three molybdenum atoms in one molecule. Molybdenum carbamate, preferably dinuclear molybdenum dithiocarbamate.

As the dinuclear molybdenum dithiocarbamate, a compound represented by the following general formula (c2-1) and a compound represented by the following general formula (c2-2) are more preferable.

[hua 4]

In the above general formulae (c2-1) and (c2-2), R ¹¹ to R ¹⁴ each independently represent a hydrocarbon group, and may be the same or different from each other.

X ¹¹ to X ¹⁸ each independently represent an oxygen atom or a sulfur atom, and may be the same or different from each other.

However, at least one of X ¹¹ to X ¹⁸ in formula (c2-1) is a sulfur atom.

In addition, in one form of this invention, it is preferable that X ¹¹ and X ¹² in formula (c2-1) are oxygen atoms, and X ¹³ to X ¹⁸ are sulfur atoms.

In the above general formula (c2-1), the molar ratio [sulfur atom/oxygen atom] of sulfur atoms in X ¹¹ to X ¹⁸ [sulfur atom/oxygen atom] is preferably 1 from the viewpoint of improving solubility with the base oil (A). /4 to 4/1, more preferably 1/3 to 3/1.

Further, X ¹¹ to X ¹⁴ in the formula (b2-2) are preferably oxygen atoms.

In the above general formulas (c2-1) and (c2-2), the number of carbon atoms of the hydrocarbon group that can be selected as R ¹¹ to R ¹⁴ is preferably 1 to 20, more preferably 5 to 18, further preferably 5 to 16, More preferably, it is 5-13.

Specific examples of the hydrocarbon group that can be selected as R ¹¹ to R ¹⁴ include the same groups as the hydrocarbon groups that can be selected as R ¹ to R ⁴ in the general formulae (c1-1) and (c1-2).

<Additives for lubricating oils>

The lubricating oil composition of one embodiment of the present invention may further contain additives for lubricating oil (hereinafter, also referred to as "lubricating oil") other than the components (B) and (C), as necessary, within the range that does not impair the effects of the present invention. with additives").

Examples of such additives for lubricating oils include pour point depressants, metal-based detergents, dispersants, anti-wear agents, extreme pressure agents, antioxidants, antifoaming agents, rust inhibitors, and metal inerting agents. .

In addition, as this additive for lubricating oils, the additive package of a commercial item containing various additives suitable for API/ILSAC SN/GF-5 standards etc. can be used.

In addition, compounds having various functions as the above-mentioned additives (for example, compounds having functions as anti-wear agents and extreme pressure agents) can also be used.

Furthermore, each additive for lubricating oil may be used individually or in combination of 2 or more types.

The respective contents of these lubricating oil additives can be appropriately adjusted within a range that does not impair the effects of the present invention, and are usually 0.001 independently of the respective additives based on the total amount (100% by mass) of the lubricating oil composition. To 15 mass %, preferably 0.005 to 12 mass %, more preferably 0.01 to 10 mass %.

In the lubricating oil composition of one embodiment of the present invention, the total content of these lubricating oil additives is preferably 0 to 40 mass %, more preferably 0, based on the total amount (100 mass %) of the lubricating oil composition. ~30 mass %, more preferably 0 to 20 mass %, still more preferably 0 to 15 mass %.

[Various Physical Properties of Lubricating Oil Compositions]

The kinematic viscosity at 40°C of the lubricating oil composition according to one embodiment of the present invention is preferably 12.0 to 45.0 mm ² /s, more preferably 15.0 to 40.0 mm ² /s, and even more preferably 20.0 to 37.0 mm ² /s .

The kinematic viscosity at 80°C of the lubricating oil composition according to one embodiment of the present invention is preferably 5.0 to 15.0 mm ² /s, more preferably 6.5 to 14.0 mm ² /s, and even more preferably 8.0 to 13.0 mm ² /s .

The kinematic viscosity at 100°C of the lubricating oil composition according to one embodiment of the present invention is preferably 2.0 to 12.0 mm ² /s, more preferably 3.0 to 10.0 mm ² /s, still more preferably 5.0 to 9.0 mm ² /s . Further, it is preferably 6.1 mm ² /s or more and less than 12.5 mm ² /s, more preferably 6.1 mm ² /s or more and 11.5 mm ² /s or less, still more preferably 6.1 mm ² /s or more and 11.0 mm ² / s or less.

The viscosity index of the lubricating oil composition according to one embodiment of the present invention is preferably 120 or more, more preferably 140 or more, still more preferably 170 or more, and still more preferably 190 or more.

The HTHS viscosity (high temperature high shear viscosity) at 80°C of the lubricating oil composition according to one embodiment of the present invention saves fuel consumption from use in a temperature environment around 80°C, which is expected to be the practical range of an engine From the viewpoint of a lubricating oil composition having good properties, it is preferably 4.0 to 8.2 mPa·s, more preferably 4.3 to 8.0 mPa·s, and even more preferably 4.7 to 7.8 mPa·s.

In addition, HTHS viscosity is also called TBS viscosity.

The HTHS viscosity at 150° C. of the lubricating oil composition of one embodiment of the present invention is preferably 2.4 to 5.5 mPa·s, more preferably 2.4 to 5.5 mPa·s, from the viewpoint of obtaining a lubricating oil composition with good fuel efficiency during high-temperature operation. It is preferably 2.5 to 5.0 mPa·s, and more preferably 2.6 to 4.5 mPa·s. Moreover, it is preferably 2.3 mPa·s or more and less than 2.9 mPa·s, more preferably 2.3 mPa·s or more and 2.8 mPa·s or less, still more preferably 2.3 mPa·s or more and 2.7 mPa·s or less.

In addition, in this specification, HTHS viscosity means the value measured by ASTM D4683.

[Manufacturing method of lubricating oil composition]

The method for producing the lubricating oil composition of the present invention is not particularly limited, but preferably a method having the following step (1),

Step (1): The ratio of Δ|α(40)| and Δ|α(100)| calculated through the following operations (i) to (iii) [Δ|α(40) to the base oil (A) )|/Δ|α(100)|] the step of the viscosity index improver (B) having a viscosity index of 1.5 or more,

Operation (i): Prepare a sample oil obtained by dissolving the viscosity index improver (B) in mineral oil, perform X-ray small-angle scattering measurement at each temperature of 40°C and 100°C, and obtain the X-ray small angle Scattering spectrum (x-axis: scattering vector q(nm ^-1 ), y-axis; commonly used log(I) of scattering intensity I);

Operation (ii): In the X-ray small-angle scattering spectrum at 40°C obtained in operation (i), in the range of 0.1 nm ^-1 to 1 nm ^-1 which is the scattering vector q of the x-axis, by the least squares method, Calculate the absolute value of the slope of the straight line Δ|α(40)|;

Operation (iii): In the X-ray small-angle scattering spectrum at 100°C obtained in operation (i), in the range of 0.1 nm ^-1 to 1 nm ^-1 which is the scattering vector q of the x-axis, by the least squares method, The absolute value Δ|α(100)| of the slope of the straight line is calculated.

In the above-mentioned step (1), the base oil (A) and the viscosity index improver (B) are as described above, and suitable components and the contents of each component are also as described above.

In addition, in this step, the above-mentioned additives for lubricating oils other than the base oil (A) and the viscosity index improver (B) may be blended.

The viscosity index improver (B) can be blended in the form of a solution dissolved in diluent oil. The solid content concentration of the solution is usually 10 to 50% by mass.

After mixing each component, it is preferable to uniformly disperse it by stirring by a well-known method.

[Use of lubricating oil composition]

The lubricating oil composition of the present invention can stably exhibit excellent fuel efficiency even when used in a wide temperature environment ranging from a low temperature range to a high temperature range.

Therefore, the lubricating oil composition of the present invention is preferably used as an engine oil.

Examples of engines suitable for use of the lubricating oil composition of the present invention include vehicle engines such as automobiles, trains, and aircraft, and the like, preferably automobile engines, and more preferably automobiles equipped with a hybrid mechanism and an idling stop mechanism. engine.

It should be noted that the lubricating oil composition of one embodiment of the present invention is suitable for use as a lubricating oil composition for internal combustion engines (engine oil for internal combustion engines) used in vehicles such as automobiles, trains, and aircrafts, but can also be applied for other purposes.

[engine]

The present invention also provides an engine comprising the above-described lubricating oil composition of the present invention.

The engine is as described above.

The lubricating oil composition of the present invention can stably exhibit excellent fuel efficiency even when used in a wide temperature environment ranging from a low temperature range to a high temperature range. Therefore, according to the engine of the present invention, even in use in a wide temperature environment ranging from a low temperature region to a high temperature region, it is possible to stably express excellent fuel economy.

[Lubrication method of engine]

The present invention also provides a method for lubricating an engine using the above-mentioned lubricating oil composition of the present invention to lubricate an engine.

The engine is as described above.

The lubricating oil composition of the present invention can stably exhibit excellent fuel efficiency even when used in a wide temperature environment ranging from a low temperature range to a high temperature range. Therefore, according to the engine lubricating method of the present invention, it is possible to stably impart excellent fuel efficiency to the engine under a wide temperature environment ranging from a low temperature region to a high temperature region.

Example

Next, the present invention will be described in more detail by way of examples, but the present invention is not limited by these examples at all. In addition, the measurement method or evaluation method of each physical property is as follows.

(1) Kinematic viscosity and viscosity index at 40°C, 80°C, and 100°C

It was measured and calculated according to JIS K2283:2000.

(2) Weight average molecular weight (Mw), number average molecular weight (Mn)

Using a gel permeation chromatograph (manufactured by Agento Co., Ltd., "1260 type HPLC"), the measurement was performed under the following conditions, and the value measured in terms of standard polystyrene was used.

(measurement conditions)

• Column: Connect two "Shodex LF404" in sequence.

·Column temperature: 35℃

Elution solvent: chloroform

• Flow rate: 0.3 mL/min.

(3) Content of molybdenum atoms

Measured according to JPI-5S-38-92.

(4) HTHS viscosity (high temperature high shear viscosity) at 80°C and 150°C

According to ASTM D4683, using a TBS high temperature viscometer (Tapered Bearing Simulator Viscometer, cone bearing simulated viscometer), under the specified temperature conditions of 80°C or 150°C, it is measured at a shear rate of 10 ⁶ /s.

In addition, the viscosity index improvers (1) to (5) used in the following Examples and Comparative Examples are as follows.

Viscosity Index Improver (1): Comb-shaped polymer having derived from methyl acrylate, hydrogenated polybutadiene (corresponding to macromonomer (x1), also monomer constituting structural unit (β1), Mn =4000 or more), 2-ethylhexyl acrylate, and a structural unit of a compound obtained by introducing an unsaturated group into glyceric acid (corresponding to a hydroxyl group-containing vinyl monomer (x2-d)). The content of the structural unit derived from the hydrogenated polybutadiene with respect to the total amount (100 mol %) of the structural unit of the comb polymer=1 mol %, Mw=550,000, and Mw/Mn=1.8.

Viscosity index improver (2): styrene-isoprene-butadiene copolymer (styrene/isoprene/butadiene=18/73/9 (mol %)). Mw=640,000, Mw/Mn=1.2.

Viscosity index improver (3): a comb polymer having a monomer derived from methyl acrylate, and hydrogenated polybutadiene (corresponding to macromonomer (x1), which is also a monomer constituting structural unit (β1), Mn=2000 or more) structural unit. The content of the structural unit derived from the hydrogenated polybutadiene with respect to the total amount (100 mol %) of the structural unit of the comb polymer=1 mol %, Mw=450,000, and Mw/Mn=5.2.

Viscosity index improver (4): styrene-isoprene copolymer (styrene/isoprene=27/73 (mol %)). Mw=130,000, Mw/Mn=1.0.

• Viscosity index improver (5): polymethyl acrylate (a homopolymer formed from methyl acrylate). Mw=400,000, Mw/Mn=2.0.

These viscosity index improvers (1) to (5) were dissolved in mineral oil (alkane-based mineral oil, mineral oil classified as API base oil category 3, kinematic viscosity at 40°C = 17.9 mm ² /s) , 100°C kinematic viscosity = 4.16 mm ² /s, viscosity index = 134) to prepare sample oil. In addition, the viscosity index improver was mix|blended so that the 100 degreeC kinematic viscosity of each sample oil might fall within the range of 7.8-8.2 mm< ² >/s.

Then, using a small-angle X-ray scattering apparatus (manufactured by Anton Paar, product name "SAXSPACE"), the quartz capillary to which the sample oil was added was set on a sample stage provided with a temperature controller of the small-angle X-ray scattering apparatus, and each was heated to After 40°C and 100°C, X-ray small-angle scattering measurements were performed to obtain X-ray small-angle scattering spectra (x-axis: scattering vector q(nm ^-1 ), y-axis; common logarithm log(I) of scattering intensity I).

Then, in the X-ray small-angle scattering spectrum at 40°C, in the range of 0.1 nm ^-1 to 1 nm ^-1 which is the scattering vector q of the x-axis, the absolute value Δ|α of the slope of the straight line was calculated by the least squares method. (40)|.

In addition, similarly, in the X-ray small-angle scattering spectrum at 100°C, in the range of 0.1 nm ^-1 to 1 nm ^-1 which is the scattering vector q of the x-axis, the absolute value of the slope of the straight line is calculated by the least squares method. The value Δ|α(100)|.

Finally, the ratio of Δ|α(40)| to Δ|α(100)| [Δ|α(40)|/Δ|α(100)|] is calculated. These values are shown in Table 1.

[Table 1]

Examples 1~3, Comparative Examples 1~2

To the base oil, any one of the viscosity index improvers (1) to (5), a pour point depressant, a friction modifier, and an engine oil additive package were added in the amounts shown in Table 2 to prepare a lubricating oil combination. thing.

It should be noted that the contents of the viscosity index improvers (1) to (5), pour point depressants, friction modifiers, and additive packages for engine oils described in Table 2 are not diluted by diluent oil when diluted with diluent oil. Content in terms of active ingredient conversion (resin component conversion) other than oil.

In addition, the details of the used base oil, pour point depressant, friction modifier, and additive package for engine oil are as described below, and details of the viscosity index improvers (1) to (5) are as described above.

Base oil: alkane-based mineral oil, mineral oil classified as API base oil category 3, 40°C kinematic viscosity=17.9mm ² /s, 100°C kinematic viscosity=4.16mm ² /s, viscosity index =134.

·Pour point depressant: polymethacrylate with Mw=70,000.

· Friction modifier: Adeka Sakura 515 (manufactured by ADEKA Co., Ltd.), molybdenum atom content=10.0 mass %, sulfur atom content=11.5 mass %. Molybdenum dinuclear dialkyldithiocarbamate (MoDTC) represented by the following formula.

[hua 5]

(In the above formula, R is each independently a hydrocarbon group having 8 or 13 carbon atoms).

·Additive package for engine oil: An additive package suitable for API/ILSAC standard and SN/GF-5 standard, including the following various additives.

Metal-based detergent: calcium salicylate

Dispersant: polymer biimide, boron-modified monoimide

Anti-wear agent: primary ZnDTP, and secondary ZnDTP

Antioxidants: diphenylamine-based antioxidants, hindered phenol-based antioxidants

Metal inerting agent: benzotriazole

Defoamer: Silicone-based defoamer.

With respect to the prepared lubricating oil compositions, the kinematic viscosity, viscosity index, and HTHS viscosity were measured or calculated according to the above-mentioned methods, and the oil temperatures 40°C and 80°C of the respective lubricating oil compositions were evaluated based on the methods shown below. lower driving torque improvement rate. These results are shown in Table 2.

[Measurement of driving torque improvement rate]

The crankshaft of a tandem 4-cylinder engine (valve mechanism: roller valve type) having a displacement of 1.5 L was driven by a motor, and the torque applied to the crankshaft at this time was measured. The measurement was performed for each case where the rotation speed of the crankshaft was 1600 rpm and the oil temperature was 40°C and 80°C.

Based on the measured value of torque when the lubricating oil composition of Comparative Example 2 was used, the driving torque improvement rate (%) when the lubricating oil composition other than Comparative Example 2 was used was calculated according to the following formula.

·[Driving torque improvement rate](%)=([Measured value of torque when using the lubricating oil composition of Comparative Example 2]-[Measured value of torque when using the target lubricating oil composition])/[Comparison of use Measured value of torque when the lubricating oil composition of Example 2] × 100

It should be noted that when the value of the driving torque improvement rate calculated from the above formula is positive, the fuel economy is higher than that of the lubricating oil composition of Comparative Example 2, while the value of the driving torque improvement rate is higher. When it is negative, compared with the lubricating oil composition of the comparative example 2, it shows that fuel economy is inferior.

That is, the larger the value of the driving torque improvement rate calculated from the above formula, the more the driving torque is improved, and it can be said that the fuel economy of the lubricating oil composition to be measured is high.

In the present Example, the driving torque improvement rate at 40° C. was defined as 0.5% or more as pass, preferably 1.0% or more, and more preferably 2.0% or more.

In addition, as the driving torque improvement rate at 80° C., 0.1% or more was regarded as pass, preferably 0.12% or more, and more preferably 0.14% or more.

[Table 2]

As a result, compared with the lubricating oil compositions of Comparative Examples 1 and 2, the lubricating oil compositions prepared in Examples 1 to 3 were found to be in a temperature environment around 40° C. expected to be the starting region of the engine, and the temperature environment expected to be In use in a temperature environment around 80°C in the practical area of this is excellent in fuel economy.

Claims (9)

1. A lubricating oil composition comprising a base oil (A) and a viscosity index improver (B) having a ratio [ Delta | alpha (40) |/Delta | alpha (100) | ] of Delta | alpha (40) | to Delta | alpha (100) |, which is calculated by the following operations (i) to (iii), of 1.5 or more,

seed operation (i): a sample oil obtained by dissolving the viscosity index improver (B) in a mineral oil was prepared, and X-ray small-angle scattering measurement was performed at 40 ℃ and 100 ℃ to obtain an X-ray small-angle scattering spectrum (X-axis: scattering vector)q(nm^-1) The y-axis; common log of scattering intensity I (I));

seed planting (ii): (ii) in the X-ray small angle scattering spectrum at 40 ℃ obtained in operation (i), at 0.1nm of the scattering vector q as the X-axis^-1~1nm^-1In the range of (1), an absolute value Δ | α (40) | of a slope of the straight line is calculated by a least square method;

seed operation (iii): (ii) in the X-ray small-angle scattering spectrum at 100 ℃ obtained in operation (i), 0.1nm as the scattering vector q of the X-axis^-1~1nm^-1In the range of (2), the absolute value Δ | α (100) | of the slope of the straight line is calculated by the least square method.

2. The lubricating oil composition according to claim 1, wherein the base oil (a) comprises a mineral oil.

3. Lubricating oil composition according to claim 2, wherein the aforementioned mineral oil is a mineral oil classified as group 2 or 3 in the base oil category of API (american petroleum institute).

4. Lubricating oil composition according to any one of claims 1 to 3, wherein the viscosity index improver (B) comprises a polymer (B1) having structural units (. beta.1) derived from a monomer selected from butadiene and hydrogenated butadiene.

5. The lubricating oil composition according to claim 4, wherein the content of the structural unit (. beta.1) is 0.1 to 70 mol% based on the total amount of the structural units of the polymer (B1).

6. The lubricating oil composition according to claim 4 or 5, wherein the polymer (B1) is 1 or more selected from a styrene-isoprene-butadiene copolymer (B11) and a comb polymer (B12).

7. The lubricating oil composition according to any one of claims 1 to 6, wherein the viscosity index improver (B) has a weight average molecular weight of 10 to 90 ten thousand.

8. The lubricating oil composition according to any one of claims 1 to 7, wherein the content of the viscosity index improver (B) in terms of resin component is 0.5 to 8.0 mass% based on the total amount of the lubricating oil composition.

9. A lubricating oil composition according to any one of claims 1 to 8 for use in an engine.