Lubricating oil composition

Abstract

The present invention provides a lubricating oil composition having both excellent brake noise preventing performance and excellent seizure resistance. The lubricating oil composition contains base oil (A), zinc dithiophosphate (B), and sarcosine-based compound (C), the content of the sarcosine-based compound (C) is more than 0.05 mass% and 0.40 mass% or less based on the total amount of the lubricating oil composition, and satisfies the following condition (α) or (β). Condition (α): In the case where the content of the sarcosine-based compound (C) is more than 0.05 mass% and less than 0.20 mass% based on the total amount of the lubricating oil composition, the phosphorus-based compound (D) is optionally contained, the phosphorus-based compound (D) being one or more selected from acidic phosphate ester (D1) and amine salt thereof (D2). Condition (β): In the case where the content of the sarcosine-based compound (C) is 0.20 mass% or more and 0.40 mass% or less based on the total amount of the lubricating oil composition, the content of the phosphorus-based compound (D) is less than 0.50 mass% based on the total amount of the lubricating oil composition.

Description

TECHNICAL FIELD

[0001] The present application relates to a lubricating oil composition. BACKGROUND

[0002] Industrial machines such as agricultural machines, construction machines, and transport machines are generally equipped with a transmission (gear) and a hydraulic working section. Also, in industrial machines, agricultural machines such as tractors, transplanter, balers, and combine harvesters; construction machines such as hydraulic excavators, cranes, and bulldozers; and transport machines such as dump trucks, forklifts, fork trucks, and all-terrain transport vehicles are also equipped with a wet brake. The transmission (gear), hydraulic working section, and wet brake equipped in these machines are generally lubricated in common with the same lubricating oil composition.

[0003] Various lubricating oil compositions used in such industrial machines have been proposed. For example, in Patent Literature 1, a working fluid composition for tractors is proposed, which contains a major amount of an oil of lubricating viscosity, a specific detergent composition, a specific amount of at least one hydrocarbyl polyol, and a specific amount of at least one zinc dialkyldithiophosphate having a secondary alkyl group.

[0004] PRIOR ART DOCUMENTS

[0005] PATENT LITERATURE

[0006] Patent Literature 1: Japanese Patent Application Laid-Open No. 2017-505852 SUMMARY

[0007] PROBLEMS TO BE SOLVED BY THE INVENTION

[0008] However, as a problem peculiar to a wet brake, there is a brake noise caused by vibration and the like due to the repetition of adhesion and sliding of a friction surface generated between friction surfaces, that is, stick-slip. Therefore, for a lubricating oil composition used in an industrial machine equipped with a wet brake, in particular, a performance of preventing a brake noise (hereinafter, also referred to as “anti-brake noise performance”) is required.

[0009] Further, in the case where the transmission (gear), hydraulic working section, and wet brake equipped in an industrial machine are lubricated in common with the same lubricating oil composition, for a lubricating oil composition used in this common lubrication, a performance of preventing seizure of the transmission (gear) (hereinafter, also referred to as “seizure resistance performance”) is also required.

[0010] However, in Patent Literature 1, no study has been made on the trade-off between the brake squeal prevention performance and the seizure resistance. Note that, for the purpose of securing the brake squeal prevention performance, a friction modifier is sometimes added to the lubricating oil composition, but if the addition amount of the friction modifier is increased, there is a tendency that the seizure resistance is decreased, and, on the contrary, if the addition amount of the friction modifier is decreased, the brake squeal prevention performance is sometimes not secured. Thus, it is difficult to trade off these performances.

[0011] Therefore, an object of the present application is to provide a lubricating oil composition excellent in both the brake squeal prevention performance and the seizure resistance.

[0012] Means for solving the object

[0013] The present inventors have made intensive studies repeatedly, and as a result, have found that a lubricating oil composition containing a base oil, zinc dithiophosphate, and a sarcosine-based compound, and satisfying specific conditions can solve the above-described object.

[0014] That is, the present application relates to the following [1] to [2].

[0015] [1] A lubricating oil composition containing a base oil (A), zinc dithiophosphate (B), and a sarcosine-based compound (C),

[0016] The content of the above-described sarcosine-based compound (C) exceeds 0.05 mass% and is 0.40 mass% or less based on the total amount of the lubricating oil composition, and satisfies the following conditions (a) or (β).

[0017] • Condition (a): In the case where the content of the above-described sarcosine-based compound (C) exceeds 0.05 mass% and is less than 0.20 mass% based on the total amount of the lubricating oil composition, the phosphorus-based compound (D) is optionally contained, which is selected from one or more of an acid phosphate ester (D1) and an amine salt thereof (D2).

[0018] • Condition (β): In the case where the content of the above-described sarcosine-based compound (C) is 0.20 mass% or more and 0.40 mass% or less based on the total amount of the lubricating oil composition, the above-described phosphorus-based compound (D) is contained in an amount of less than 0.50 mass% based on the total amount of the lubricating oil composition.

[0019] [2] A lubricating method for an industrial machine, which uses the lubricating oil composition described in the above [1].

[0020] Effects of the Invention

[0021] According to the present application, it is possible to provide a lubricating oil composition excellent in both the brake squeal prevention performance and the seizure resistance. DETAILED DESCRIPTION

[0022] The upper limit value and the lower limit value of the numerical range described in the present specification can be combined arbitrarily. For example, in the case where "A to B" and "C to D" are described as numerical ranges, the numerical ranges of "A to D" and "C to B" are also included in the scope of the present application.

[0023] In addition, the numerical range "lower limit value to upper limit value" described in the present specification means above the lower limit value and below the upper limit value unless otherwise specified.

[0024] In addition, in the present specification, the numerical value of the examples is a numerical value that can be used as the upper limit value or the lower limit value.

[0025] [Mode of the Lubricating Oil Composition of the Invention]

[0026] The lubricating oil composition of the present application contains base oil (A), zinc dithiophosphate (B), and sarcosine-based compound (C). Also, in the lubricating oil composition of the present application, the content of the above-mentioned sarcosine-based compound (C) exceeds 0.05 mass% and is 0.40 mass% or less based on the total amount of the lubricating oil composition, and satisfies the following conditions (a) or (b).

[0027] • Condition (a): In the case where the content of the above-mentioned sarcosine-based compound (C) exceeds 0.05 mass% and is less than 0.20 mass% based on the total amount of the lubricating oil composition, the phosphorus-based compound (D) is optionally contained, which is selected from one or more of the acidic phosphoric ester (D1) and the amine salt thereof (D2).

[0028] • Condition (b): In the case where the content of the above-mentioned sarcosine-based compound (C) is 0.20 mass% or more and 0.40 mass% or less based on the total amount of the lubricating oil composition, the above-mentioned phosphorus-based compound (D) is contained in an amount of less than 0.50 mass% based on the total amount of the lubricating oil composition.

[0029] The present inventors and others have conducted intensive studies in order to solve the above-mentioned problems. As a result, the present inventors and others have found that the lubricating oil composition containing base oil (A), zinc dithiophosphate (B), and sarcosine-based compound (C), and adjusting the content of the sarcosine-based compound (C) to a specific range is excellent in both the brake squeal preventing performance and the seizure resistance. In addition, the present inventors and others have found that by further compounding in the above-mentioned lubricating oil composition one or more of the phosphorus-based compound (D) selected from the acidic phosphoric ester (D1) and the amine salt thereof (D2), it is possible to expand the range of the content of the sarcosine-based compound (C) that makes both the brake squeal preventing performance and the seizure resistance good. Based on these, the present inventors and others have further repeatedly conducted various studies, thereby completing the present application.

[0030] As to the mechanism of exerting the effect of the present application, for example, the following is presumed. That is, in the case of the lubricating oil composition in which only zinc dithiophosphate (B) is incorporated, or the lubricating oil composition in which only zinc dithiophosphate (B) and the phosphorus-based compound (D) are incorporated, although the seizure resistance is exerted, the brake squeal preventive performance is not exerted, and thus it is presumed that the incorporation of the sarcosine-based compound (C) in a specific amount in the lubricating oil composition greatly contributes to the exertion of the brake squeal preventive performance. However, if the amount of the sarcosine-based compound (C) incorporated exceeds the specific amount, the brake squeal preventive performance cannot be exerted, and thus it is known that, in the case where the sarcosine-based compound (C) alone is contained for the brake squeal preventive performance, there is an appropriate amount of incorporation. On the other hand, in the case where it is desired to further incorporate the sarcosine-based compound exceeding the above appropriate amount due to various circumstances, the brake squeal preventive performance cannot be exerted as described above, and thus some countermeasure is required. The present inventors have clarified through various studies that, in such a case, by incorporating the phosphorus-based compound (D), the brake squeal preventive performance is exerted even in the case where the amount of incorporation of the sarcosine-based compound (C) alone does not exert the brake squeal preventive performance. As to the reason why the brake squeal preventive performance is exerted even in the case where the amount of incorporation of the sarcosine-based compound (C) alone does not exert the brake squeal preventive performance by thus incorporating the phosphorus-based compound (D), it is presumed that some interaction occurs between the sarcosine-based compound (C) and the phosphorus-based compound (D).

[0031] The lubricating oil composition of one embodiment of the present application can be composed of only the base oil (A) (hereinafter also referred to as "component (A)"), zinc dithiophosphate (B) (hereinafter also referred to as "component (B)"), and the sarcosine-based compound (C) (hereinafter also referred to as "component (C)"), and under certain conditions, can further contain the phosphorus-based compound (D) (hereinafter also referred to as "component (D)").

[0032] That is, the lubricating oil composition of one embodiment of the present application can be composed of only the component (A), the component (B), and the component (C), and can be composed of only the component (A), the component (B), the component (C), and the component (D).

[0033] In addition, the lubricating oil composition of one embodiment of the present application can further contain another component other than the component (A), the component (B), the component (C), and the component (D).

[0034] In the lubricating oil composition of one embodiment of the present application, the total content of the component (A), the component (B), and the component (C) is preferably 70 mass% or more, more preferably 75 mass% or more, and further preferably 80 mass% or more, relative to the total amount of the lubricating oil composition. In addition, it is preferably 100 mass% or less, more preferably 97 mass% or less, and further preferably 95 mass% or less.

[0035] The upper and lower limits of these numerical ranges can be combined arbitrarily. Specifically, it is preferably 70% to 100% by mass, more preferably 75% to 97% by mass, and even more preferably 80% to 95% by mass.

[0036] Furthermore, in one embodiment of the lubricating oil composition of the present invention, the total content of components (A), (B), (C), and (D) is preferably 70% by mass or more, more preferably 75% by mass or more, and even more preferably 80% by mass or more, based on the total amount of the lubricating oil composition. Additionally, it is preferably 100% by mass or less, more preferably 97% by mass or less, and even more preferably 95% by mass or less.

[0037] The upper and lower limits of these numerical ranges can be combined arbitrarily. Specifically, it is preferably 70% to 100% by mass, more preferably 75% to 97% by mass, and even more preferably 80% to 95% by mass.

[0038] Hereinafter, the conditions (α) and conditions (β) specified in the lubricating oil composition of the present invention will be described in detail, and then the components constituting the lubricating oil composition of the present invention will be described in detail.

[0039] <Condition (α) and Condition (β)>

[0040] The lubricating oil composition of the present invention satisfies condition (α) or condition (β).

[0041] The effects of the present invention cannot be achieved if the lubricating oil composition does not meet either condition (α) or condition (β).

[0042] The following is a detailed explanation of conditions (α) and (β).

[0043] (Condition(α))

[0044] In the lubricating oil composition of the present invention, the conditions (α) are specified as follows.

[0045] • Condition (α): When the content of sarcosine compound (C) is more than 0.05% by mass and less than 0.20% by mass based on the total amount of the lubricating oil composition, it may optionally contain one or more phosphorus compounds (D) selected from acidic phosphate esters (D1) and their amine salts (D2).

[0046] In the lubricating oil composition of the present invention, the content of sarcosine compounds (C) is limited, based on the total amount of the lubricating oil composition, to be more than 0.05% by mass and less than 0.40% by mass. In condition (α), within this limitation range, the manner in which the content exceeds 0.05% by mass and is less than 0.20% by mass is specified.

[0047] That is, in the case where the content of the sarcosine-based compound (C) exceeds 0.05 mass% and is less than 0.20 mass%, the phosphorus-based compound (D) can be contained or can not be contained. In either case, the effects of the present application are exerted. In addition, in the condition (a), in the case where the lubricating oil composition contains the phosphorus-based compound (D), the content thereof is not limited.

[0048] Note that, in the condition (a), in the case where the phosphorus-based compound (D) is not contained, from the viewpoint of more easily exerting the effects of the present application, the content of the sarcosine-based compound (C) in the condition (a) is preferably 0.07 mass% or more, more preferably 0.08 mass% or more, and further preferably 0.09 mass% or more, based on the total amount of the lubricating oil composition. In addition, it is preferably 0.16 mass% or less, more preferably 0.13 mass% or less, and further preferably 0.11 mass% or less.

[0049] The upper limit value and the lower limit value of these numerical ranges can be combined arbitrarily. Specifically, it is preferably 0.07 mass% to 0.16 mass%, more preferably 0.08 mass% to 0.13 mass%, and further preferably 0.09 mass% to 0.11 mass%.

[0050] In addition, in the condition (a), in the case where the phosphorus-based compound (D) is contained, from the viewpoint of more easily exerting the effects of the present application, the content of the sarcosine-based compound (C) in the condition (a) is preferably 0.07 mass% or more, more preferably 0.08 mass% or more, and further preferably 0.09 mass% or more, based on the total amount of the lubricating oil composition. In addition, it is preferably 0.19 mass% or less.

[0051] The upper limit value and the lower limit value of these numerical ranges can be combined arbitrarily. Specifically, it is preferably 0.07 mass% to 0.19 mass%, more preferably 0.08 mass% to 0.19 mass%, and further preferably 0.09 mass% to 0.19 mass%.

[0052] Here, in the case where the lubricating oil composition of one embodiment of the present application satisfies the condition (a), from the viewpoint of more easily exerting the effects of the present application, it is more preferably satisfies any one of the condition (al) and the condition (a2) described below, and further preferably satisfies both of the condition (al) and the condition (a2) described below.

[0053] -Condition (al)-

[0054] In the lubricating oil composition of one embodiment of the present application, the condition (al) is specified as follows.

[0055] • Condition (al): the contained ratio [(C) / (B)] of the sarcosine-based compound (C) to zinc dithiophosphate (B) is more than 0.04 and less than 0.17 in terms of mass ratio.

[0056] By having [(C) / (B)] in the above range, the effect of the present application can be more easily exerted.

[0057] Here, in condition (al), in the case where the phosphorus-based compound (D) is not contained, [(C) / (B)] is preferably 0.05 or greater, more preferably 0.06 or greater, and further preferably 0.07 or greater in terms of mass ratio from the viewpoint of more easily exerting the effect of the present application. In addition, it is preferably 0.14 or less, more preferably 0.11 or less, and further preferably 0.10 or less.

[0058] The upper limit value and the lower limit value of these numerical ranges can be combined arbitrarily. Specifically, it is preferably 0.05 to 0.14, more preferably 0.06 to 0.11, and further preferably 0.07 to 0.10.

[0059] In addition, in condition (al), in the case where the phosphorus-based compound (D) is contained, [(C) / (B)] is preferably 0.05 or greater, more preferably 0.06 or greater, and further preferably 0.07 or greater in terms of mass ratio from the viewpoint of more easily exerting the effect of the present application. In addition, it is preferably 0.16 or less.

[0060] The upper limit value and the lower limit value of these numerical ranges can be combined arbitrarily. Specifically, it is preferably 0.05 to 0.16, more preferably 0.06 to 0.16, and further preferably 0.07 to 0.16.

[0061] -Condition (a2)-

[0062] In the lubricating oil composition of one embodiment of the present application, condition (a2) is specified as follows.

[0063] • Condition (a2): the contained ratio [(D) / (B)] of the phosphorus-based compound (D) to zinc dithiophosphate (B) is 1.04 or less in terms of mass ratio.

[0064] By having [(D) / (B)] in the above range, the effect of the present application can be more easily exerted.

[0065] Here, from the viewpoint of easily producing a lubricating oil composition having more excellent scuffing resistance, the [(D) / (B)] in the condition (a2) is preferably less than 1.04, more preferably 0.90 or less, further preferably 0.80 or less, and still further preferably 0.70 or less, in terms of mass ratio. Note that the lubricating oil composition satisfying the condition (a2) can not contain the phosphorus compound (D), and thus the lower limit value of the [(D) / (B)] can be 0.00 in terms of mass ratio.

[0066] (Condition (β))

[0067] In the lubricating oil composition of the present application, the condition (β) is specified as follows.

[0068] • Condition (β): In the case where the content of the sarcosine compound (C) is 0.20 mass% or more and 0.40 mass% or less based on the total amount of the lubricating oil composition, less than 0.50 mass% of the above-mentioned phosphorus compound (D) is contained based on the total amount of the lubricating oil composition.

[0069] In the lubricating oil composition of the present application, the content of the sarcosine compound (C) is limited to more than 0.05 mass% and 0.40 mass% or less based on the total amount of the lubricating oil composition. In the condition (β), the provision is made for the range of 0.20 mass% or more and 0.40 mass% or less within the range of the limitation. By satisfying the provision, the effect of the present application is exerted even in the case where the above-mentioned condition (a) is not satisfied.

[0070] Note that in the condition (β), the phosphorus compound (D) must be contained in the lubricating oil composition. In the condition (β), the effect of the present application cannot be exerted in the case where the lubricating oil composition does not contain the phosphorus compound (D). Among them, the content of the phosphorus compound (D) is limited to less than 0.50 mass%.

[0071] Here, from the viewpoint of easily producing a lubricating oil composition having more excellent scuffing resistance, the content of the sarcosine compound (C) in the condition (β) is preferably less than 0.40 mass%, more preferably 0.35 mass% or less, and further preferably 0.30 mass% or less, based on the total amount of the lubricating oil composition.

[0072] In addition, from the viewpoint of more easily exerting the effect of the present application, the content of the phosphorus compound (D) in the condition (β) is preferably 0.40 mass% or less, more preferably 0.35 mass% or less, and further preferably 0.30 mass% or less. In addition, it is preferably 0.10 mass% or more, more preferably 0.15 mass% or more, and further preferably 0.20 mass% or more.

[0073] The upper limit value and the lower limit value of these numerical ranges can be combined arbitrarily. Specifically, 0.10 to 0.40% by mass, more preferably 0.15 to 0.35% by mass, further preferably 0.20 to 0.30% by mass is preferable.

[0074] In this case, in the lubricating oil composition of one embodiment of the present application, in the case where the condition (β) is satisfied, from the viewpoint of more easily exerting the effects of the present application, either one of the conditions (β1) and (β2) described below is more preferably satisfied, and both of the conditions (β1) and (β2) described below are further preferably satisfied.

[0075] -Condition (β1)-

[0076] In the lubricating oil composition of one embodiment of the present application, the condition (β1) is specified as follows.

[0077] • Condition (β1): the ratio of the content of the sarcosine-based compound (C) to the content of the zinc dithiophosphate (B) [(C) / (B)] is less than or equal to 0.33 in terms of mass ratio.

[0078] By setting [(C) / (B)] to the above range, the effects of the present application can be more easily exerted.

[0079] In this case, from the viewpoint of easily producing a lubricating oil composition having more excellent seizure resistance, [(C) / (B)] in the condition (β1) is preferably less than 0.33, more preferably 0.30 or less, further preferably 0.27 or less, and much further preferably 0.25 or less in terms of mass ratio. In addition, from the viewpoint of much further easily exerting the effects of the present application, it is preferably 0.10 or more, more preferably 0.15 or more, and further preferably 0.17 or more.

[0080] The upper limit value and the lower limit value of these numerical ranges can be combined arbitrarily. Specifically, 0.10 to 0.40% by mass, more preferably 0.15 to 0.35% by mass, further preferably 0.20 to 0.30% by mass is preferable.

[0081] -Condition (β2)-

[0082] In the lubricating oil composition of one embodiment of the present application, the condition (β2) is specified as follows.

[0083] • Condition (β2): the ratio of the content of the phosphorus-based compound (D) to the content of the zinc dithiophosphate (B) [(D) / (B)] is less than 0.42 in terms of mass ratio.

[0084] By setting [(D) / (B)] to the above range, the effects of the present application can be more easily exerted.

[0085] In this regard, the [(D) / (B)] in the condition (β2) is preferably 0.35 or less, more preferably 0.30 or less, and further preferably 0.25 or less, from the viewpoint of more easily exerting the effects of the present application. In addition, it is preferably 0.10 or more, more preferably 0.15 or more, and further preferably 0.17 or more.

[0086] The upper limit value and the lower limit value of these numerical ranges can be combined arbitrarily. Specifically, it is preferably 0.10 to 0.35, more preferably 0.15 to 0.30, and further preferably 0.17 to 0.25.

[0087] <Base oil (A)>

[0088] The lubricating oil composition of the present application contains a base oil (A).

[0089] As the base oil (A), one or more selected from the group consisting of mineral oils and synthetic oils that have been used as base oils for lubricating oils in the past can be used without particular limitation.

[0090] As the mineral oil, for example, there can be mentioned atmospheric residue obtained by subjecting paraffin-based crude oil, intermediate-based crude oil, or naphthenic-based crude oil, or the like to atmospheric distillation; distillate oil obtained by subjecting these atmospheric residue to vacuum distillation; mineral oils obtained by subjecting the distillate oil to one or more of solvent deasphalting, solvent extraction, hydrocracking, solvent dewaxing, catalytic dewaxing, and refining treatments such as hydrorefining; and the like.

[0091] The mineral oil is preferably a mineral oil classified as Group 2 or Group 3 in the base oil categories of the American Petroleum Institute (API).

[0092] As the synthetic oil, for example, there can be mentioned poly-α-olefins such as α-olefin homopolymers and α-olefin copolymers (e.g., ethylene-α-olefin copolymers and the like α-olefin copolymers having a carbon number of 8 to 14); isomeric paraffins; various esters such as polyol esters and dibasic acid esters; various ethers such as polyphenylene ethers; polyalkylene glycols; alkylbenzenes; alkylnaphthalenes; GTL base oils obtained by subjecting waxes (GTL waxes) manufactured from natural gas using the Fischer-Tropsch method or the like to isomerization; and the like.

[0093] The base oil (A) can use a mineral oil alone or a plurality of mineral oils in combination, or can use a synthetic oil alone or a plurality of synthetic oils in combination. In addition, one or more mineral oils and one or more synthetic oils can be used in combination.

[0094] In the lubricating oil composition of one embodiment of the present application, the base oil (A) preferably contains a mineral oil. In this case, the content of the mineral oil is preferably 50% by mass or more, more preferably 60% by mass or more, further preferably 70% by mass or more, more further preferably 80% by mass or more, and still further preferably 90% by mass or more, relative to the total amount of the base oil (A).

[0095] The 100°C kinematic viscosity of the base oil (A) is preferably 1 mm 2 / s or more, more preferably 2 mm 2 / s or more, further preferably 3 mm 2 / s or more. In addition, the 100°C kinematic viscosity of the base oil (A) is preferably 25 mm 2 / s or less, more preferably 20 mm 2 / s or less, further preferably 15 mm 2 / s or less. If the 100°C kinematic viscosity of the base oil (A) is within the above range, it is advantageous in terms of improvement in the seizure prevention performance and the wear prevention performance of the transmission (gear), the viscosity characteristics, the stability against oxidation deterioration, and the like, in addition to the brake noise prevention performance.

[0096] The upper limit value and the lower limit value of these numerical ranges can be combined arbitrarily. Specifically, the 100°C kinematic viscosity of the base oil (A) is preferably 1 mm 2 / s to 25 mm 2 / s or more, more preferably 2 mm 2 / s to 20 mm 2 / s or more, further preferably 3 mm 2 / s to 25 mm 2 / s.

[0097] The viscosity index of the base oil (A) is preferably 100 or more, more preferably 110 or more, and further preferably 120 or more. If the viscosity index of the base oil (A) is within the above range, it is advantageous in terms of improvement in the seizure prevention performance and the wear prevention performance of the transmission (gear), the viscosity characteristics, the stability against oxidation deterioration, and the like, in addition to the brake noise prevention performance.

[0098] Note that in the case where the base oil (A) is a mixed base oil containing two or more kinds of base oils, the 100°C kinematic viscosity and the viscosity index of the mixed base oil are preferably within the above ranges.

[0099] In this specification, the 100°C kinematic viscosity and the viscosity index of the base oil (A) mean values measured or calculated in accordance with JIS K 2283:2000.

[0100] (Content of base oil (A))

[0101] The content of the base oil (A) in the lubricating oil composition of one embodiment of the present application is preferably 95 mass% or less, relative to the total amount of the lubricating oil composition. By making the content of the base oil (A) 95 mass% or less, the amounts of the zinc dithiophosphate (B) and the sarcosine-based compound (C) and the phosphorus-based compound (D) in the lubricating oil composition can be sufficiently ensured, and the effects of the present application can be easily exhibited.

[0102] Note that the content of the base oil (A) is more preferably 93 mass% or less and further preferably 92 mass% or less, relative to the total amount of the lubricating oil composition, from the viewpoint of more easily exhibiting the effects of the present application. In addition, the content of the base oil (A) is preferably 65 mass% or more, more preferably 70 mass% or more, and further preferably 75 mass% or more.

[0103] The upper limit value and the lower limit value of these numerical ranges can be combined arbitrarily. Specifically, the content of the base oil (A) is preferably 65 mass% to 95 mass%, more preferably 70 mass% to 93 mass%, and further preferably 75 mass% to 92 mass%.

[0104] Note that the lubricating oil composition of one embodiment of the present application, as described later, sometimes contains other additives in addition to the viscosity index improver, and these additives are sometimes provided in a state of being diluted with a diluent oil and sometimes directly mixed into the lubricating oil composition in a state of being diluted with a diluent oil. In this case, the diluent oil is also included in the content of the base oil (A) described above.

[0105] <Zinc dithiophosphate (B)>

[0106] The lubricating oil composition of the present application contains a zinc dithiophosphate (B).

[0107] In the case where the lubricating oil composition does not contain the zinc dithiophosphate (B), the effects (particularly, the seizure resistance) of the present application cannot be exhibited.

[0108] As the zinc dithiophosphate (B), a zinc dithiophosphate that has been widely used as an additive for lubricating oil in the past can be used without particular limitation. Note that one kind of the zinc dithiophosphate (B) can be used alone or two or more kinds thereof can be used in combination.

[0109] In the lubricating oil composition of one embodiment of the present application, as the zinc dithiophosphate (B), a compound represented by General Formula (b-1) described below is preferably used from the viewpoint of more easily exhibiting the effects of the present application.

[0110] [Chemical Formula 1]

[0111]

[0112] In General Formula (b-1), Rb1 ~R b4 each independently represents a hydrocarbon group.

[0113] As the hydrocarbon group which can be selected as R b1 ~R b4 , if it is a monovalent hydrocarbon group, there is no particular limitation, and for example, an alkyl group, an alkenyl group, a cycloalkyl group, an aryl group, and the like can be preferably selected, more preferably an alkyl group and an aryl group, and further preferably an alkyl group.

[0114] That is, the zinc dithiophosphate (B) used in the lubricating oil composition of one embodiment of the present application is more preferably a zinc dialkyldithiophosphate, a zinc diaryldithiophosphate, and further preferably a zinc dialkyldithiophosphate.

[0115] The alkyl group and the alkenyl group which can be selected as R b1 ~R b4 may be either of a linear shape and a branched shape.

[0116] In addition, in the case where R b1 ~R b4 is an alkyl group, the zinc dithiophosphate (B) can be a primary dialkyldithiophosphate in which R b1 ~R b4 is a primary alkyl group, or a secondary dialkyldithiophosphate in which R b1 ~R b4 is a secondary alkyl group, and from the viewpoint of stability of the zinc dithiophosphate (B), it is preferable to use a primary dialkyldithiophosphate.

[0117] Note that the cycloalkyl group and the aryl group which can be selected as R b1 ~R b4 may be, for example, polycyclic groups such as decalinyl (Japanese: decaryl group) and naphthyl.

[0118] In addition, the monovalent hydrocarbon group which can be selected as R b1 ~R b4 may have a substituent containing an oxygen atom and / or a nitrogen atom such as a hydroxyl group, a carboxyl group, an amino group, an amide group, a nitro group, a cyano group, or can be a group in which a part of the group is substituted with a nitrogen atom, an oxygen atom, a halogen atom, or the like.

[0119] In addition, the number of carbons of the hydrocarbon group which can be selected as R b1 ~R b4 , in the case where the monovalent hydrocarbon group is an alkyl group, is preferably 1 or more, more preferably 2 or more, and further preferably 3 or more, and as an upper limit, is preferably 24 or less, more preferably 18 or less, and further preferably 12 or less.

[0120] In the case where the monovalent hydrocarbon is an alkenyl group, the carbon number is preferably 2 or more, more preferably 3 or more, and as an upper limit, 24 or less, more preferably 18 or less, and further preferably 12 or less.

[0121] In the case where the monovalent hydrocarbon is a cycloalkyl group, the carbon number is preferably 5 or more, and as an upper limit, 20 or less, and in the case where the monovalent hydrocarbon is an aryl group, the carbon number is preferably 6 or more, and as an upper limit, 20 or less.

[0122] Note that the compound represented by the following general formula (b-1) can be used alone or in combination with two or more kinds.

[0123] (Content of zinc dithiophosphate (B))

[0124] In the lubricating oil composition of one embodiment of the present application, the content of zinc dithiophosphate (B) is preferably 0.50% by mass or more, more preferably 0.80% by mass or more, further preferably 1.00% by mass or more, and still further preferably 1.10% by mass or more, relative to the total amount of the lubricating oil composition, from the viewpoint of easily exerting the effects of the present application. In addition, it is preferably 2.00% by mass or less, more preferably 1.60% by mass or less, further preferably 1.40% by mass or less, and still further preferably 1.30% by mass or less.

[0125] The upper limit and the lower limit of these numerical ranges can be combined arbitrarily. Specifically, it is preferably 0.50% by mass to 2.00% by mass, more preferably 0.80% by mass to 1.60% by mass, further preferably 1.00% by mass to 1.40% by mass, and still further preferably 1.10% by mass to 1.30% by mass.

[0126] <Serine compound (C)>

[0127] The lubricating oil composition of the present application contains a serine compound (C).

[0128] The lubricating oil composition of the present application is excellent in both brake noise preventing performance and seizure resistance by containing a serine compound (C) and satisfying the following condition (α) or condition (β). In the case where the lubricating oil composition does not contain a serine compound (C), the effects of the present application (particularly, brake noise preventing performance) cannot be exerted.

[0129] Note that the serine compound (C) can be used alone or in combination with two or more kinds.

[0130] In the lubricating oil composition of one embodiment of the present application, as the serine compound (C), a serine compound (C1) represented by the following general formula (c-1) is preferably used from the viewpoint of more easily exerting the effects of the present application.

[0131] [Chemical Formula 2]

[0132]

[0133] In General Formula (c-1) above, R c1 represents a hydrocarbon group having a carbon number of 2 to 30 which can contain a hetero atom, R c2 represents a hydrogen atom or a methyl group.

[0134] As the hydrocarbon group which can be selected as R c1 , if it is a monovalent hydrocarbon group, there is no particular limitation, and for example, an alkyl group having a carbon number of 2 to 30, a cycloalkyl group having a carbon number of 3 to 30, an alkenyl group having a carbon number of 3 to 30 can be mentioned. These monovalent hydrocarbon groups can contain a hetero atom. Specifically, a substituent containing an oxygen atom and / or a nitrogen atom such as a hydroxyl group, a carboxyl group, an amino group, an amido group, a nitro group, a cyano group, or the like can be possessed, and a group in which a part is substituted with a nitrogen atom, an oxygen atom, a halogen atom, or the like can also be possessed.

[0135] The carbon number of the hydrocarbon group which can be selected as R c1 is preferably 8 to 26, more preferably 12 to 24, and further preferably 16 to 20. In addition, R c1 is preferably an alkyl group and an alkenyl group which can have a substituent, and more preferably an alkenyl group which can have a substituent.

[0136] As the alkyl group which can have a substituent which can be selected as R c1 , for example, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group, an undecyl group, a dodecyl group, a tridecyl group, a tetradecyl group, a hexadecyl group, an octadecyl group, a tetracosyl group, a hexacosyl group, and the like can be mentioned. Note that the alkyl group can be a straight chain alkyl group or a branched chain alkyl group.

[0137] As the cycloalkyl group which can have a substituent which can be selected as R c1 , for example, a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, an adamantyl group, and the like can be mentioned. Note that the cycloalkyl group can be substituted with an alkyl group having a carbon number of 1 to 10 (preferably 1 to 4).

[0138] As the alkenyl group which can have a substituent which can be selected as R c1 , for example, a propenyl group, a butenyl group, a pentenyl group, a hexenyl group, a heptenyl group, an octenyl group, a nonenyl group, a decenyl group, an undecenyl group, a dodecenyl group, a tridecenyl group, a tetradecenyl group, a hexadecenyl group, an octadecenyl group, a tetracosenyl group, a hexacosenyl group, and the like can be mentioned. Note that the alkenyl group can be a straight chain alkenyl group or a branched chain alkenyl group.

[0139] Note that the sarcosine-based compound (C1) can be used alone or in combination with two or more kinds.

[0140] In this case, in the lubricating oil composition of one embodiment of the present application, as the sarcosine-based compound (C1), a sarcosine-based compound (C2) represented by General Formula (c-2) is more preferably used from the viewpoint of more easily exerting the effects of the present application.

[0141] [Chemical Formula 3]

[0142]

[0143] [In General Formula (c-2), R C3 represents a hydrocarbon group having a carbon number of 1 to 29.]

[0144] As the hydrocarbon group that can be selected as R c3 , if it is a monovalent hydrocarbon group, there is no particular limitation, and examples include an alkyl group having a carbon number of 1 to 29, a cycloalkyl group having a carbon number of 3 to 29, and an alkenyl group having a carbon number of 3 to 29.

[0145] The carbon number of the hydrocarbon group that can be selected as R c3 is preferably 7 to 25, more preferably 11 to 23, and further preferably 15 to 19. In addition, R c3 is preferably an alkyl group and an alkenyl group, and more preferably an alkenyl group.

[0146] As the alkyl group, cycloalkyl group, and alkenyl group that can be selected as R c3 , the same groups as those exemplified as R c1 can be given.

[0147] As a specific example of the sarcosine-based compound (C2) represented by General Formula (c-2), N-oleoyl sarcosine (R c3 is an alkenyl group having a carbon number of 17) can be given.

[0148] Note that the sarcosine-based compound (C2) can be used alone or in combination with two or more kinds.

[0149] (Content of the sarcosine-based compound (C))

[0150] In the lubricating oil composition of the present application, the content of the sarcosine-based compound (C) is more than 0.05 mass% and 0.40 mass% or less relative to the total amount of the lubricating oil composition.

[0151] If the content of the sarcosine-based compound (C) is 0.05 mass% or less, the braking noise preventing performance cannot be good.

[0152] Further, if the content of the sarcosine-based compound (C) exceeds 0.40 mass%, it is not possible to obtain good seizure resistance.

[0153] Here, from the viewpoint of easily obtaining good brake noise prevention performance, the content of the sarcosine-based compound (C) is preferably 0.07 mass% or more, more preferably 0.08 mass% or more, further preferably 0.09 mass% or more, and more further preferably 0.10 mass% or more, based on the total amount of the lubricating oil composition.

[0154] Further, from the viewpoint of obtaining good seizure resistance, the content of the sarcosine-based compound (C) is preferably less than 0.40 mass%, more preferably 0.35 mass% or less, and further preferably 0.30 mass% or less, based on the total amount of the lubricating oil composition.

[0155] The upper limit value and the lower limit value of these numerical ranges can be combined arbitrarily. Specifically, it is preferable that the content of the sarcosine-based compound (C) be 0.07 mass% or more and less than 0.40 mass%, more preferably 0.08 mass% or more and less than 0.40 mass%, further preferably 0.09 mass% to 0.35 mass%, and more further preferably 0.10 mass% to 0.30 mass%, based on the total amount of the lubricating oil composition.

[0156] <Phosphorus-based compound (D)>

[0157] In the case where the lubricating oil composition of the present application satisfies the above condition (a), a phosphorus-based compound (D) selected from one or more of an acid phosphate (D1) and an amine salt thereof (D2) is optionally contained.

[0158] Further, in the case where the lubricating oil composition of the present application satisfies the above condition (β), the above phosphorus-based compound (D) is contained.

[0159] As described above, by compounding in the lubricating oil composition one or more of a phosphorus-based compound (D) selected from an acid phosphate (D1) and an amine salt thereof (D2), it is possible to expand the range of the content of the sarcosine-based compound (C) in which both brake noise prevention performance and seizure resistance are good. That is, in the case where the content of the sarcosine-based compound (C) in the range of 0.20 mass% or more and 0.40 mass% or less as specified by the above condition (β), it is not possible to make both brake noise prevention performance and seizure resistance good by using only the sarcosine-based compound (C), but in the case where the content of the sarcosine-based compound (C) is in this range, by compounding a specific amount of the phosphorus-based compound (D), it is possible to make both brake noise prevention performance and seizure resistance good.

[0160] Note that the phosphorus-based compound (D) does not include zinc dithiophosphate (B).

[0161] In the lubricating oil composition of one embodiment of the present application, as the acidic phosphoric ester (D1) used as the phosphorus-based compound (D), a compound represented by General Formula (d-1) below is preferably used from the viewpoint of more easily exerting the effects of the present application.

[0162] Chemical Formula 4

[0163]

[0164] In General Formula (d-1), R d1 Each independently represents a hydrocarbon group having a carbon number of 1 to 30. As the hydrocarbon group, an alkyl group, an alkenyl group, an aryl group, an arylalkyl group, or the like can be preferably selected from the viewpoint of more excellent wear resistance.

[0165] In the case where R d1 In the case where R is an alkyl group, the carbon number is preferably 2 to 20 from the viewpoint of more excellent wear resistance, ease of availability, and the like. The alkyl group can be any of a linear shape, a branched shape, and a cyclic shape, and is preferably a linear shape or a branched shape, further considering ease of availability and the like.

[0166] In the case where R d1 In the case where R is an alkenyl group, the carbon number is preferably 2 to 20 from the viewpoint of more excellent wear resistance, ease of availability, and the like. The alkenyl group can be any of a linear shape, a branched shape, and a cyclic shape, and is preferably a linear shape or a branched shape.

[0167] In the case where R d1 In the case where R is an aryl group, the carbon number is preferably 6 to 20, and more preferably 6 to 15, from the viewpoint of more excellent seizure resistance and wear resistance, ease of availability, and the like.

[0168] In the case where R d1 In the case where R is an arylalkyl group, the carbon number is preferably 6 to 20, and more preferably 6 to 15, from the viewpoint of more excellent seizure resistance and wear resistance, ease of availability, and the like.

[0169] In General Formula (d-1), m represents 1 or 2.

[0170] When m = 2, a plurality of R d1 may be the same or different from each other.

[0171] As the acid phosphoric ester represented by the above general formula (d-1), for example, mono(di)ethyl acid phosphoric ester, mono(di)n-propyl acid phosphoric ester, mono(di)2- ethylhexyl acid phosphoric ester, mono(di)butyl acid phosphoric ester, mono(di)octyl acid phosphoric ester, mono(di)dodecyl acid phosphoric ester, mono(di)oleylic acid phosphoric ester, mono(di)isodecyl acid phosphoric ester, mono(di)lauryl acid phosphoric ester, mono(di)stearyl acid phosphoric ester, mono(di)isostearyl acid phosphoric ester, and the like can be given.

[0172] The compound represented by the general formula (d-1) can be used alone as one kind, or two or more kinds can be used in combination.

[0173] Further, as the amine salt (D2) of the acid phosphoric ester, an amine salt formed from the above acid phosphoric ester (D1) and an amine can be preferably given. Here, as the amine used in the formation of the amine salt, primary amines, secondary amines, tertiary amines, polyalkylene amines, and the like can be given, and as the primary amines, secondary amines, and tertiary amines, amines represented by the following general formula (d-2) can be given.

[0174] [Chemical Formula 5]

[0175]

[0176] In the general formula (d-2), R d2 represents a hydrocarbon group having a carbon number of 1 to 30. In the case where the hydrocarbon group is an alkyl group, it can be a hydroxyalkyl group in which at least one of the hydrogen atoms possessed by the alkyl group is substituted with a hydroxyl group.

[0177] R d2 is preferably an alkyl group having a carbon number of 6 to 18, an alkenyl group having a carbon number of 6 to 18, an aromatic group having a ring-forming carbon number of 6 to 18, an arylalkyl group having a carbon number of 7 to 18, or a hydroxyalkyl group having a carbon number of 6 to 18, and more preferably an alkyl group having a carbon number of 6 to 18.

[0178] Further, n is 1, 2, or 3, and when n is 1, it is a primary amine, when n is 2, it is a secondary amine, and when n is 3, it is a tertiary amine.

[0179] As the polyalkylene amine, for example, ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, hexaethylenheptamine, heptaethyleneoctamine, tetrapropylenepentamine, hexabutylenheptamine, and the like can be given.

[0180] The amine salt of the above acid phosphoric ester (D1) and the amine or polyamine represented by the above general formula (d-2) can be used alone as one kind, or two or more kinds can be used in combination.

[0181] (Content of the phosphorus-based compound (D))

[0182] In the lubricating oil composition of one embodiment of the present application, in the case where condition (a) is satisfied, the content of the phosphorus-based compound (D) is preferably 0.05% by mass or more, more preferably 0.10% by mass or more, and still more preferably 0.13% by mass or more, relative to the total amount of the lubricating oil composition, from the viewpoint of more easily exerting the effects of the present application. In addition, it is preferably 1.25% by mass or less, more preferably less than 1.25% by mass, and still more preferably 1.00% by mass or less.

[0183] These upper and lower limits of the numerical ranges can be combined arbitrarily. Specifically, it is preferably 0.05% by mass or more and 1.25% by mass or less, more preferably 0.10% by mass or more and less than 1.25% by mass, and still more preferably 0.13% by mass or more and 1.00% by mass or less.

[0184] In addition, in the lubricating oil composition of one embodiment of the present application, in the case where condition (β) is satisfied, the content of the phosphorus-based compound (D) is as specified in condition (β), and the appropriate range is also the same as the above appropriate range in condition (β).

[0185] <Other conditions>

[0186] In the lubricating oil composition of one embodiment of the present application, in the case where condition (a) is satisfied, the ratio of the content of the phosphorus-based compound (D) to the content of the sarcosine-based compound (C) [(D) / (C)] is preferably more than 0.50, more preferably 1.10 or more, and still more preferably 1.30 or more, in terms of mass ratio, from the viewpoint of more easily exerting the effects of the present application. In addition, it is preferably 12.5 or less, more preferably less than 12.5, and still more preferably 10.0 or less.

[0187] These upper and lower limits of the numerical ranges can be combined arbitrarily. Specifically, it is preferably 0.50 or more and 12.5 or less, more preferably 1.10 or more and less than 12.5, and still more preferably 1.30 or more and 10.0 or less.

[0188] In addition, in the lubricating oil composition of one embodiment of the present application, in the case where condition (β) is satisfied, the ratio of the content of the phosphorus-based compound (D) to the content of the sarcosine-based compound (C) [(D) / (C)] is preferably 0.40 or more, more preferably 0.50 or more, still more preferably 0.55 or more, yet more preferably 0.65 or more, and even more preferably 0.70 or more, in terms of mass ratio, from the viewpoint of more easily exerting the effects of the present application. In addition, it is preferably less than 1.67, more preferably 1.40 or less, and still more preferably 1.30 or less.

[0189] The upper limit and the lower limit of these numerical ranges can be combined arbitrarily. Specifically, it is preferable that the upper limit be 0.40 or more and the lower limit be less than 1.67, more preferable that the upper limit be 0.50 or more and the lower limit be 1.40 or less, further preferable that the upper limit be 0.55 or more and the lower limit be 1.30 or less, more further preferable that the upper limit be 0.65 or more and the lower limit be 1.30 or less, still further preferable that the upper limit be 0.70 or more and the lower limit be 1.30 or less.

[0190] <Other additives>

[0191] The lubricating oil composition of one embodiment of the present application can contain an additive other than the above components (A) to (D) (hereinafter also referred to as "other additive") without greatly impairing the effects of the present application.

[0192] As the other additive, an antioxidant, a friction modifier, an oiliness agent, an anticorrosive agent (metal deactivator), a detergent, a dispersant, a viscosity index improver, a pour point depressant, an antifoaming agent, a rust preventive, an extreme pressure agent, and the like can be given. These additives can be used alone at one kind or in combination with two or more kinds.

[0193] The total content of the other additive is preferably 0 mass% or more and 25 mass% or less, more preferably 0 mass% or more and 20 mass% or less, further preferably 0 mass% or more and 16 mass% or less, with respect to the total amount of the lubricating oil composition.

[0194] (Antioxidant)

[0195] As the antioxidant, for example, a monoalkyl diphenylamine having an alkyl group with a carbon number of approximately 3 to 10, such as monoteriary butyl diphenylamine; a dialkyl diphenylamine in which each alkyl group has a carbon number of approximately 3 to 10, such as 4,4'-dibutyl diphenylamine; a polyalkyl diphenylamine having three or more alkyl groups and each alkyl group having a carbon number of approximately 1 to 10, such as tetrabutyl diphenylamine; an alkyl-substituted phenyl-alpha-naphthylamine having at least one alkyl group with a carbon number of approximately 1 to 12, such as methylphenyl-alpha-naphthylamine; a phenyl-alpha-naphthylamine, such as phenyl-alpha-naphthylamine; a mono-hindered amine-based antioxidant, such as methacrylic acid 2,2,6,6-tetramethylpiperidyl ester; a bisphenol-based antioxidant, such as 4,4'-methylenebis(2,6-di-tert-butylphenol) bis(3-methyl-4-hydroxy-5-tert-butylbenzyl) sulfide; a monophenol-based antioxidant, such as 2,6-di-tert-butyl-4-methylphenol, n-octadecyl 3-(4-hydroxy-3,5-di-tert-butylphenyl)propionate; and the like can be given.

[0196] They can be used alone at one kind or in combination with two or more kinds.

[0197] (Friction modifier)

[0198] As the friction modifier, for example, there can be mentioned ashless friction modifiers such as aliphatic amines having at least one alkyl group or alkenyl group with a carbon number of 6 to 30 in the molecule, fatty acid esters, fatty acid amides, fatty acids, aliphatic alcohols, aliphatic ethers, and the like.

[0199] They can be used singly one kind or in combination two or more kinds.

[0200] (Oily agent)

[0201] As the oily agent, for example, there can be mentioned aliphatic alcohols; fatty acid compounds such as fatty acids and fatty acid metal salts; ester compounds such as polyol esters, sorbitol esters, and glycerol esters; amine compounds such as aliphatic amines; and the like.

[0202] They can be used singly one kind or in combination two or more kinds.

[0203] (Anti-corrosion agent (metal deactivator))

[0204] As the anti-corrosion agent (metal deactivator), for example, there can be mentioned benzotriazole-based compounds, methylbenzotriazole-based compounds, imidazole-based compounds, pyrimidine-based compounds, and the like.

[0205] They can be used singly one kind or in combination two or more kinds.

[0206] (Detergent)

[0207] As the detergent, there can be mentioned metal-based detergents such as salicylate salts, sulfonate salts, phenate salts of sodium, calcium, magnesium, and the like.

[0208] They can be used singly one kind or in combination two or more kinds.

[0209] (Dispersant)

[0210] As the dispersant, there can be mentioned ashless dispersants such as boron-free succinimides, boron-containing succinimides, benzylamines, boron-containing benzylamines, succinates, and mono- or di-carboxylic amides represented by fatty acids or succinic acid.

[0211] They can be used singly one kind or in combination two or more kinds.

[0212] (Viscosity index improver)

[0213] As the viscosity index improver, for example, there can be mentioned non-dispersed polymethacrylates (PMA), dispersed polymethacrylates, olefin-based copolymers (olefin copolymer (OCP); for example, ethylene-propylene copolymers and the like), dispersed olefin-based copolymers, styrene-based copolymers (for example, styrene-diene hydrogenated copolymers and the like), and the like.

[0214] They can be used singly or in combination of two or more.

[0215] Here, as the viscosity index improver, a non-dispersed polymethacrylate (PMA) is preferably used.

[0216] Further, as the non-dispersed polymethacrylate (PMA), the mass average molecular weight (Mw) is preferably in the range of 10,000 to 300,000, and two or more kinds of different mass average molecular weight (Mw) are preferably used in combination.

[0217] Note that the mass average molecular weight (Mw) of the viscosity index improver is a value calculated by using a gel permeation chromatography and converted to polystyrene.

[0218]

[0219] As the pour point depressant, for example, ethylene-vinyl acetate copolymer, condensate of chlorinated paraffin and naphthalene, condensate of chlorinated paraffin and phenol, polymethacrylate, polyalkylstyrene, and the like polymers can be given. The weight average molecular weight (Mw) of these polymers is preferably 50,000 to 150,000.

[0220]

[0221] As the defoaming agent, for example, silicone oil, fluorosilicone oil, and the like silicone-based defoaming agents, fluorine alkyl ether, and the like fluorine-based defoaming agents, and the like can be given.

[0222] They can be used singly or in combination of two or more.

[0223]

[0224] As the rust preventive, for example, petroleum sulfonate, alkylbenzene sulfonate, dinonyl naphthalene sulfonate, alkenyl succinate, polyol ester, and the like can be given.

[0225] They can be used singly or in combination of two or more.

[0226]

[0227] As the extreme pressure agent, for example, sulfurized olefin, hydrocarbon sulfide, sulfurized oil, sulfurized fatty acid, sulfurized ester, and the like sulfur-based extreme pressure agents; phosphoric acid ester, phosphite, hydrogen phosphite, and the like phosphoric acid ester compounds, and amine salts of the phosphoric acid ester compounds, and the like phosphorus-based compounds (D) other than the phosphorus-based extreme pressure agent; monothiophosphoric acid ester, dithiophosphoric acid ester, trithiophosphoric acid ester, amine salt of monothiophosphoric acid ester, amine salt of dithiophosphoric acid ester, monothiophosphite, dithiophosphite, trithiophosphite, and the like extreme pressure agents containing sulfur atom and phosphorus atom can be given.

[0228] They can be used singly or in combination of two or more. ​​​​

[0229] From the viewpoint of maximizing the effect of the addition of the phosphorus-based compound (D), it is preferable that the content of the one or more extreme pressure agents selected from the group consisting of phosphorus-based extreme pressure agents and extreme pressure agents containing both sulfur and phosphorus, other than the phosphorus-based compound (D), be small.

[0230] Specifically, the content of the phosphorus-based extreme pressure agent other than the phosphorus-based compound (D) and the extreme pressure agent containing both sulfur and phosphorus is each independently preferably less than 0.01% by mass, more preferably less than 0.005% by mass, further preferably less than 0.001% by mass, and more further preferably contains none of these extreme pressure agents.

[0231] [Properties of the lubricating oil composition]

[0232] [40°C kinematic viscosity, 100°C kinematic viscosity, viscosity index]

[0233] The 40°C kinematic viscosity of the lubricating oil composition of one embodiment of the present application is preferably 10 mm 2 / s or more, more preferably 20 mm 2 / s or more, further preferably 30 mm 2 / s or more, and preferably 70 mm 2 / s or less, more preferably 60 mm 2 / s or less, further preferably 50 mm 2 / s or less.

[0234] The upper limit value and the lower limit value of these numerical ranges can be combined arbitrarily. Specifically, it is preferable that the 40°C kinematic viscosity be 10 mm 2 / s or more and 70 mm 2 / s or less, more preferably 20 mm 2 / s or more and 60 mm 2 / s or less, further preferably 30 mm 2 / s or more and 50 mm 2 / s or less.

[0235] In addition, the 100°C kinematic viscosity of the lubricating oil composition of one embodiment of the present application is preferably 5.0 mm 2 / s or more, more preferably 6.0 mm 2 / s or more, further preferably 6.5 mm 2 / s or more, more further preferably 7.0 mm 2 / s or more, and preferably 11 mm 2 / s or less, more preferably 10 mm 2 / s or less, further preferably 9.0 mm 2 / s or less.

[0236] The upper limit and lower limit of these numerical ranges can be combined arbitrarily. Specifically, 5.0 mm 2 or more and 11 mm 2 or less, more preferably 6.0 mm 2 or more and 10 mm 2 or less, further preferably 6.5 mm 2 or more and 9.0 mm 2 or less, still further preferably 7.0 mm 2 or more and 9.0 mm 2 or less.

[0237] In addition, the viscosity index of the lubricating oil composition of one embodiment of the present application is preferably 180 or greater, more preferably 190 or greater, and further preferably 200 or greater.

[0238] If the kinematic viscosity and the viscosity index of the lubricating oil composition are in the above range, it is easy to improve the anti-wear properties and viscosity characteristics, along with the improvement in the anti-brake noise properties and the seizure resistance.

[0239] Note that the 40°C kinematic viscosity, the 100°C kinematic viscosity, and the viscosity index of the lubricating oil composition are measured by the same method as that of the base oil (A) described above.

[0240] <Base number>

[0241] The base number of the lubricating oil composition of one embodiment of the present application is preferably 4 mgKOH / g or greater, preferably 5 mgKOH / g or greater, and preferably 6 mgKOH / g or greater. In addition, it is typically 12 mgKOH / g or less.

[0242] If the base number of the lubricating oil composition is in the above range, it is advantageous in terms of improving the detergency and dispersion, and the stability against oxidative deterioration.

[0243] The base number of the lubricating oil composition is a value measured by the potentiometric method (hydrochloric acid method) in accordance with JIS K2501:2003.

[0244] <Various atomic contents>

[0245] From the viewpoint of more easily exerting the effects of the present application, the various atomic contents of the lubricating oil composition of one embodiment of the present application are preferably in the following ranges.

[0246] Note that the contents of calcium atoms, phosphorus atoms, zinc atoms, and sulfur atoms in the lubricating oil composition are values measured in accordance with JIS-5S-38-03.

[0247] In addition, the content of nitrogen atoms in the lubricating oil composition is a value measured in accordance with JIS K2609:1998.

[0248] (calcium atom content)

[0249] The calcium atom content of the lubricating oil composition of one embodiment of the present application is preferably 5000 parts by mass or less, more preferably 4500 parts by mass or less, and further preferably 4200 parts by mass or less, relative to the total amount of the lubricating oil composition. In addition, it is preferably 2500 parts by mass or more, more preferably 3000 parts by mass or more, and further preferably 3500 parts by mass or more.

[0250] The upper limit value and the lower limit value of these numerical ranges can be arbitrarily combined. Specifically, it is preferably 2500 parts by mass or more and 5000 parts by mass or less, more preferably 3000 parts by mass or more and 4500 parts by mass or less, and further preferably 3500 parts by mass or more and 4200 parts by mass or less.

[0251] (phosphorus atom content)

[0252] The phosphorus atom content of the lubricating oil composition of one embodiment of the present application is preferably 2000 parts by mass or less, more preferably 1500 parts by mass or less, and further preferably 1300 parts by mass or less, relative to the total amount of the lubricating oil composition. In addition, it is preferably 500 parts by mass or more, more preferably 700 parts by mass or more, and further preferably 800 parts by mass or more.

[0253] The upper limit value and the lower limit value of these numerical ranges can be arbitrarily combined. Specifically, it is preferably 500 parts by mass or more and 2000 parts by mass or less, more preferably 700 parts by mass or more and 1500 parts by mass or less, and further preferably 800 parts by mass or more and 1300 parts by mass or less.

[0254] (zinc atom content)

[0255] The zinc atom content of the lubricating oil composition of one embodiment of the present application is preferably 2000 parts by mass or less, more preferably 1500 parts by mass or less, and further preferably 1200 parts by mass or less, relative to the total amount of the lubricating oil composition. In addition, it is preferably 500 parts by mass or more, more preferably 800 parts by mass or more, and further preferably 1000 parts by mass or more.

[0256] The upper limit value and the lower limit value of these numerical ranges can be arbitrarily combined. Specifically, it is preferably 500 parts by mass or more and 2000 parts by mass or less, more preferably 800 parts by mass or more and 1500 parts by mass or less, and further preferably 1000 parts by mass or more and 1200 parts by mass or less.

[0257] (sulfur atom content)

[0258] The sulfur atom content of the lubricating oil composition of one embodiment of the present application is preferably 0.30% by mass or less, more preferably 0.25% by mass or less, and further preferably 0.23% by mass or less, relative to the total amount of the lubricating oil composition. In addition, it is preferably 0.10% by mass or more, more preferably 0.15% by mass or more, and further preferably 0.20% by mass or more.

[0259] The upper limit value and the lower limit value of these numerical ranges can be arbitrarily combined. Specifically, it is preferably 0.10% by mass or more and 0.30% by mass or less, more preferably 0.15% by mass or more and 0.25% by mass or less, and further preferably 0.20% by mass or more and 0.23% by mass or less.

[0260] (nitrogen atom content)

[0261] The nitrogen atom content of the lubricating oil composition of one embodiment of the present application is preferably 1200 mass ppm or less, more preferably 900 mass ppm or less, and further preferably 700 mass ppm or less, relative to the total amount of the lubricating oil composition. In addition, it is preferably 250 mass ppm or more, more preferably 300 mass ppm or more, and further preferably 350 mass ppm or more.

[0262] The upper limit value and the lower limit value of these numerical ranges can be arbitrarily combined. Specifically, it is preferably 250 mass ppm or more and 1200 mass ppm or less, more preferably 300 mass ppm or more and 900 mass ppm or less, and further preferably 350 mass ppm or more and 700 mass ppm or less.

[0263] <friction coefficient μ 50 >

[0264] The friction coefficient μ at 80°C of the lubricating oil composition of one embodiment of the present application is preferably less than 0.115, more preferably 0.114 or less, further preferably 0.113 or less, still further preferably 0.112 or less, and yet further preferably 0.111 or less, which is measured on the basis of JASO M 349:2012 using a low-speed sliding friction tester (an LVFA tester) under the conditions of the examples described later. s0

[0265] <load capacity>

[0266] The load capacity (seizure resistance) of the lubricating oil composition of one embodiment of the present application is preferably more than 0.50 MPa, more preferably 0.55 MPa or more, and further preferably more than 0.55 MPa, and still further preferably 0.60 MPa or more, which is measured under the conditions of the examples described later.​

[0267] [Method for producing lubricating oil composition]

[0268] The method for producing the lubricating oil composition of the present application is not particularly limited, and for example, the following production method can be mentioned.

[0269] That is, a method for producing a lubricating oil composition, which is a method for producing a lubricating oil composition having a step (S1) of blending a base oil (A), zinc dithiophosphate (B), and a sarcosine-based compound (C),

[0270] The content of the above-mentioned sarcosine-based compound (C) is adjusted to be more than 0.05 mass% and 0.40 mass% or less based on the total amount of the above-mentioned lubricating oil composition in such a manner as to satisfy the following conditions (α) or (β).

[0271] • Condition (S1α): In the case where the blending amount of the above-mentioned sarcosine-based compound (C) is adjusted to be more than 0.05 mass% and less than 0.20 mass% based on the total amount of the above-mentioned lubricating oil composition, the above-mentioned phosphorus-based compound (D) selected from one or more of an acid phosphate ester (D1) and an amine salt thereof (D2) is optionally blended.

[0272] • Condition (S1β): In the case where the blending amount of the above-mentioned sarcosine-based compound (C) is adjusted to be 0.20 mass% or more and 0.40 mass% or less based on the total amount of the above-mentioned lubricating oil composition, the above-mentioned phosphorus-based compound (D) is blended in an amount of less than 0.50 mass% based on the total amount of the above-mentioned lubricating oil composition.

[0273] There is no particular limitation on the order of blending the above-mentioned components, and for example, zinc dithiophosphate (B), a sarcosine-based compound (C), a phosphorus-based compound (D), and other additives can be sequentially blended in a base oil (A), or two or more selected from zinc dithiophosphate (B), a sarcosine-based compound (C), a phosphorus-based compound (D), and other additives can be previously mixed and then blended.

[0274] [Use of lubricating oil composition]

[0275] The lubricating oil composition of the present application is excellent in both the antibraking noise performance and the seizure resistance. Therefore, it is suitable for use in industrial machines. In addition, in the case where the industrial machines, such as tractors, rice transplanters, balers, combine harvesters, and the like, construction machines, such as hydraulic excavators, cranes, and the like, transport machines, such as dump trucks, forklifts, and the like, are commonly lubricated, the noise of the wet brake can be prevented, and the seizure of the transmission (gear) can be prevented. Therefore, it is suitable for use in these applications.

[0276] [Method for lubrication]

[0277] The method for lubrication of the present application is a method for lubrication using the lubricating oil composition of the present application.

[0278] Both the anti-brake noise performance and the seizure resistance performance of the lubricating oil composition of the present application are excellent. Therefore, the method for lubrication of the present application can effectively utilize the above-mentioned performances of the lubricating oil composition of the present application, and is thus suitable for use in industrial machines. In addition, in the case where common lubrication is performed on industrial machines equipped with a transmission (gear), a hydraulic working section, and a wet brake, such as a tractor, a rice transplanter, a baler, a combine harvester, and the like agricultural machines, a hydraulic excavator, a crane, a bulldozer, a dump truck, a forklift truck, a pallet truck, and the like transportation machines, the use of the present application is also suitable.

[0279] [Industrial machine]

[0280] The industrial machine of the present application contains the lubricating oil composition of the present application.

[0281] The industrial machine of one embodiment of the present application is preferably an industrial machine equipped with a transmission (gear), a hydraulic working section, and a wet brake.

[0282] As the industrial machine equipped with a transmission (gear), a hydraulic working section, and a wet brake, for example, there can be mentioned a tractor, a rice transplanter, a baler, a combine harvester, and the like agricultural machines, a hydraulic excavator, a crane, a bulldozer, a dump truck, a forklift truck, a pallet truck, and the like transportation machines, and the like. In addition, among these industrial machines, from the viewpoint that the excellent performances of the lubricating oil composition of the present application can be effectively utilized, it is preferable that the industrial machine be equipped with a mechanism for performing common lubrication on the transmission (gear), the hydraulic working section, and the wet brake.

[0283] [One embodiment of the present application provided]

[0284] According to one embodiment of the present application, [1] to

[13] described below are provided.

[0285] [1] A lubricating oil composition containing a base oil (A), zinc dithiophosphate (B), and a sarcosine-based compound (C),

[0286] The content of the above-mentioned sarcosine-based compound (C) exceeds 0.05 mass% and is 0.40 mass% or less based on the total amount of the above-mentioned lubricating oil composition, and satisfies the following condition (α) or (β).

[0287] • Condition (a): In the case where the content of the sarcosine-based compound (C) described above exceeds 0.05 mass% and is less than 0.20 mass% based on the total amount of the lubricating oil composition, the phosphorus-based compound (D) is optionally contained.

[0288] • Condition (β): In the case where the content of the sarcosine-based compound (C) described above is 0.20 mass% or more and 0.40 mass% or less based on the total amount of the lubricating oil composition, the phosphorus-based compound (D) described above is contained in an amount of less than 0.50 mass% based on the total amount of the lubricating oil composition.

[0289] [2] The lubricating oil composition according to the above [1], wherein in the case where the above condition (a) is satisfied, the following condition (al) is also satisfied.

[0290] • Condition (al): The ratio of the content of the sarcosine-based compound (C) to the content of the zinc dithiophosphate (B) [(C) / (B)] exceeds 0.04 and is less than 0.17 in terms of mass ratio.

[0291] [3] The lubricating oil composition according to the above [1] or [2], wherein in the case where the above condition (a) is satisfied, the following condition (a2) is also satisfied.

[0292] • Condition (a2): The ratio of the content of the phosphorus-based compound (D) to the content of the zinc dithiophosphate (B) [(D) / (B)] is 1.04 or less in terms of mass ratio.

[0293] [4] The lubricating oil composition according to the above [1], wherein in the case where the above condition (β) is satisfied, the following condition (βl) is also satisfied.

[0294] • Condition (βl): The ratio of the content of the sarcosine-based compound (C) to the content of the zinc dithiophosphate (B) [(C) / (B)] is 0.33 or less in terms of mass ratio.

[0295] [5] The lubricating oil composition according to the above [1] or [4], wherein in the case where the above condition (β) is satisfied, the following condition (β2) is also satisfied.

[0296] • Condition (β2): The ratio of the content of the phosphorus-based compound (D) to the content of the zinc dithiophosphate (B) [(D) / (B)] is less than 0.42 in terms of mass ratio.

[0297] [6] The lubricating oil composition according to any one of the above [1] to [5], wherein the sarcosine-based compound (C) is a sarcosine-based compound (Cl) represented by the following general formula (c-1).

[0298] [Chemical Formula 6]

[0299]

[0300] [In the above general formula (c-1), R c1 represents a hydrocarbon group having a carbon number of 2 to 30 which can contain a hetero atom, R c2 represents a hydrogen atom or a methyl group.]

[0301] [7] The lubricating oil composition according to the above [6], wherein the sarcosine-based compound (C1) is a sarcosine-based compound (C2) represented by the following general formula (c-2).

[0302] [Chemical Formula 7]

[0303]

[0304] [In the above general formula (c-2), R C3 represents a hydrocarbon group having a carbon number of 1 to 29.]

[0305] [8] The lubricating oil composition according to any one of the above [1] to [7], which is used for lubrication of an industrial machine.

[0306] [9] The lubricating oil composition according to the above [8], wherein the industrial machine has a transmission, a hydraulic working section, and a wet brake.

[0307]

[10] The lubricating oil composition according to the above [8] or [9], wherein the industrial machine is an agricultural machine.

[0308]

[11] A lubrication method of an industrial machine, which uses the lubricating oil composition according to any one of the above [1] to [7].

[0309]

[12] The lubrication method according to the above

[11] , wherein the industrial machine has a transmission, a hydraulic working section, and a wet brake.

[0310]

[13] The lubrication method according to the above

[11] or

[12] , wherein the industrial machine is an agricultural machine.

[0311] Examples

[0312] The present application is specifically described by the following examples, but the present application is not limited to the following examples.

[0313] [Measurement method of various physical values]

[0314] Each raw material used in each example and comparative example and each property of the lubricating oil composition of each example and comparative example was measured in accordance with the following gist.

[0315] (1) 40°C kinematic viscosity, 100°C kinematic viscosity and viscosity index

[0316] The 40°C kinematic viscosity, 100°C kinematic viscosity and viscosity index of the base oil were measured and calculated in accordance with JIS K2283:2000.

[0317] In addition, the 40°C kinematic viscosity, 100°C kinematic viscosity and viscosity index of the lubricating oil composition were also measured and calculated in accordance with JIS K2283:2000.

[0318] (2) Base number

[0319] The base number of the lubricating oil composition was measured by the potentiometric method (hydrochloric acid method) in accordance with JIS K2501:2003.

[0320] (3) Various atomic contents

[0321] The contents of calcium atoms, phosphorus atoms, zinc atoms and sulfur atoms in the lubricating oil composition were measured in accordance with JIS-5S-38-03.

[0322] In addition, the content of nitrogen atoms in the lubricating oil composition was measured in accordance with JIS K2609:1998.

[0323] [Examples 1 to 9, Comparative Examples 1 to 7]

[0324] The base oils and various additives shown below were thoroughly mixed in the compounding amounts (mass %) shown in Table 1 to prepare lubricating oil compositions, respectively.

[0325] The details of the base oils and various additives used in Examples 1 to 9 and Comparative Examples 1 to 7 are shown below.

[0326] <Base oil (A)>

[0327] • "100N mineral oil": 40°C kinematic viscosity = 30.0 mm 2 / s, 100°C kinematic viscosity = 4.5 mm 2 / s, viscosity index = 125

[0328] • "500N mineral oil": 40°C kinematic viscosity = 90.5 mm 2 / s, 100°C kinematic viscosity = 10.9 mm 2 / s, viscosity index = 107

[0329] <Zinc dithiophosphate (B)>

[0330] • "Primary dialkyldithiophosphoric acid zinc (primary ZnDTP)": a mixture of compounds in which the primary group of alkyl groups is a primary alkyl group having a carbon number of 4 and the other alkyl groups include primary alkyl groups having carbon numbers of 6 and 8

[0331] < sarcosine-based compound (C) >

[0332] • "N-oleoylsarcosine": a sarcosine-based compound in which R c3 in the above general formula (c-2) is an alkenyl group having a carbon number of 17.

[0333] < phosphorus-based compound (D) >

[0334] • "amine salt of acidic phosphoric ester (D2)": an amine salt of an alkyl acid phosphoric ester and an alkenyl acid phosphoric ester

[0335] The alkyl acid phosphoric ester and the alkenyl acid phosphoric ester are a mixture of monooleyl acid phosphoric ester, monocapryl acid phosphoric ester, dioleyl acid phosphoric ester, dioctyl acid phosphoric ester, and dilauryl acid phosphoric ester.

[0336] The amine salt is a mixture of dodecylamine salt and undecylamine salt.

[0337] • "acidic phosphoric ester (D1)": oleyl acid phosphoric ester

[0338] < viscosity index improver >

[0339] • "viscosity index improver A": non-dispersed polymethacrylate (Mw = 14 x 10 5 , resin component content = 39 mass%)

[0340] • "viscosity index improver B": non-dispersed polymethacrylate (Mw = 2.9 x 10 5 , resin component content = 58 mass%)

[0341] • "viscosity index improver C": non-dispersed polymethacrylate (Mw = 5.0 x 10 5 , resin component content = not clear)

[0342] The mass average molecular weight (Mw) of each viscosity index improver is a value calculated by gel permeation chromatography and converted to polystyrene.

[0343] < other additives >

[0344] friction modifier, antifoaming agent, oiliness agent, antioxidant, dispersant, metal-based detergent, metal deactivator, rust preventive, etc.

[0345] [evaluation 1: evaluation of brake noise prevention performance]

[0346] For the lubricating oil compositions prepared in the examples and comparative examples, the friction coefficient in the friction plate (A795.D0AK) and the steel plate (FZ132-8-Y2) was measured using a low-speed sliding friction tester (LVFA tester) based on JASO M349:2012.

[0347] The test oil temperature at the time of measurement was set to 80°C, and the surface pressure was set to 1 MPa.

[0348] The friction coefficient was measured by the friction coefficient μ 50 Evaluation was performed.

[0349] It can be said that the smaller the friction coefficient μ 50 is, the better the brake noise preventing performance is, because stick-slip is less likely to occur. In contrast, the larger the friction coefficient μ 50 is, the worse the brake noise preventing performance is, because stick-slip is more likely to occur.

[0350] In the present examples, the brake noise preventing performance was evaluated according to the following criteria.

[0351] • The friction coefficient μ 50 is 0.114 or less: Evaluation A (excellent brake noise preventing performance)

[0352] • The friction coefficient μ 50 is 0.115 or more: Evaluation F (poor brake noise preventing performance)

[0353] [Evaluation 2: Evaluation of Extreme Pressure Property]

[0354] The load resistance (stick-slip resistance) was evaluated using the Senda four-ball tester at a rotation speed of 200 rpm according to JIS K2519:1995.

[0355] In the present examples, the stick-slip resistance was evaluated according to the following criteria.

[0356] • The load resistance is more than 0.55 MPa: Evaluation A (excellent stick-slip resistance)

[0357] • The load resistance is more than 0.50 MPa and 0.55 MPa or less: Evaluation B (slightly excellent stick-slip resistance)

[0358] • The load resistance is 0.50 MPa or less: Evaluation F (poor stick-slip resistance)

[0359] The results are shown in Tables 1 and 2.

[0360] Note that in Tables 1 and 2, the content of each viscosity index improver refers to the content including the diluent oil as well. In addition, in each lubricating oil composition, the total content of the diluent oil from viscosity index improvers A to C exceeds 5.50 mass% to less than 6.00 mass% based on the total amount of the lubricating oil composition.

[0361] [Table 1]

[0362]

[0363] [Table 2]

[0364]

[0365] The following can be seen from Tables 1 and 2.

[0366] The lubricating oil compositions of Examples 1 to 6 are excellent in the brake squeal preventing property and the seizure resistance by containing the base oil (A), the zinc dithiophosphate (B), and the sarcosine-based compound (C) and satisfying the condition (α).

[0367] The lubricating oil compositions of Examples 7 to 9 are excellent in the brake squeal preventing property and the seizure resistance by containing the base oil (A), the zinc dithiophosphate (B), and the sarcosine-based compound (C) and satisfying the condition (β).

[0368] On the other hand, the lubricating oil compositions of Comparative Examples 1, 5, and 6 are poor in the brake squeal preventing property because they do not contain the sarcosine-based compound (C). Note that it can be seen that even in the case of containing the phosphorus-based compound (D), the lubricating oil composition as in Comparative Examples 5 and 6 is poor in the brake squeal preventing property if it does not contain the sarcosine-based compound (C).

[0369] It can be seen that the lubricating oil composition of Comparative Example 2 is poor in the brake squeal preventing property although it contains the base oil (A), the zinc dithiophosphate (B), and the sarcosine-based compound (C) because the content of the sarcosine-based compound (C) is 0.05 mass%.

[0370] It can be seen that the lubricating oil compositions of Comparative Examples 3, 4, and 7 are poor in the brake squeal preventing property although they contain the base oil (A), the zinc dithiophosphate (B), and the sarcosine-based compound (C) because neither the condition (α) nor the condition (β) is satisfied.

Claims

1. A lubricating oil composition containing base oil A, zinc dithiophosphate B, and sarcosine-based compound C, the content of the sarcosine-based compound C exceeds 0.05 mass% and is 0.40 mass% or less based on the total amount of the lubricating oil composition, and satisfies the following condition (a) or (β), in the case where the condition (a) is satisfied, the following condition (al) is also satisfied, • Condition (a): in the case where the content of the sarcosine-based compound C exceeds 0.05 mass% and is less than 0.20 mass% based on the total amount of the lubricating oil composition, the phosphorus-based compound D is optionally contained, the phosphorus-based compound D being selected from one or more of acidic phosphoric ester Dl and amine salt D2 thereof, • Condition (β): in the case where the content of the sarcosine-based compound C is 0.20 mass% or more and 0.40 mass% or less based on the total amount of the lubricating oil composition, the phosphorus-based compound D is contained at more than 0 mass% and less than 0.50 mass% based on the total amount of the lubricating oil composition, • Condition (al): the ratio of the content of the sarcosine-based compound C to the zinc dithiophosphate B, that is, C / B, exceeds 0.04 and is less than 0.17 in mass ratio.

2. The lubricating oil composition according to claim 1, wherein the total content of the component A, the component B, and the component C is 70 mass% or more and 100 mass% or less based on the total amount of the lubricating oil composition.

3. The lubricating oil composition according to claim 1, wherein the total content of the component A, the component B, the component C, and the component D is 70 mass% or more and 100 mass% or less based on the total amount of the lubricating oil composition.

4. The lubricating oil composition according to any one of claims 1 to 3, wherein in the condition (a), in the case where the phosphorus-based compound D is not contained, the content of the sarcosine-based compound C in the condition (a) is 0.07 mass% or more and 0.16 mass% or less based on the total amount of the lubricating oil composition.

5. The lubricating oil composition according to any one of claims 1 to 3, wherein in the condition (a), in the case where the phosphorus-based compound D is contained, the content of the sarcosine-based compound C in the condition (a) is 0.07 mass% or more and 0.19 mass% or less based on the total amount of the lubricating oil composition.

6. The lubricating oil composition according to any one of claims 1 to 3, wherein in the condition (al), in the case where the phosphorus-based compound D is not contained, C / B is 0.05 or more and 0.14 or less.

7. The lubricating oil composition according to any one of claims 1 to 3, wherein in the condition (al), in the case where the phosphorus-based compound D is contained, C / B is 0.05 or more and 0.16 or less.

8. The lubricating oil composition of any of claims 1-3, wherein, in the case where the condition (a) is satisfied, the following condition (a2) is also satisfied, • Condition (a2): the ratio of the content of the phosphorus-based compound D to the zinc dithiophosphate B, that is, D / B, is 1.04 or less in mass ratio.

9. The lubricating oil composition according to any one of claims 1 to 3, wherein The content of the phosphorus-based compound D in the condition (β) is 0.10 mass% or more and 0.40 mass% or less based on the total amount of the lubricating oil composition.

10. The lubricating oil composition of any of claims 1-3, wherein, In the case where the condition (β) is satisfied, the following condition (β1) is also satisfied, ・Condition (β1): The ratio of the content of the sarcosine-based compound C to the content of the zinc dithiophosphate B, that is, C / B is 0.33 or less in terms of mass ratio.

11. The lubricating oil composition according to claim 10, wherein, C / B in the condition (β1) is 0.10 or more and less than 0.

33.

12. The lubricating oil composition of any of claims 1-3, wherein, In the case where the condition (β) is satisfied, the following condition (β2) is also satisfied, ・Condition (β2): The ratio of the content of the phosphorus-based compound D to the content of the zinc dithiophosphate B, that is, D / B is less than 0.42 in terms of mass ratio.

13. The lubricating oil composition according to claim 12, wherein, D / B in the condition (β2) is 0.10 or more and 0.35 or less.

14. The lubricating oil composition according to any one of claims 1 to 3, wherein, The base oil A is one or more selected from mineral oil and synthetic oil.

15. The lubricating oil composition according to claim 14, wherein, The mineral oil is one or more selected from atmospheric residue obtained by subjecting paraffin-based crude oil, intermediate-based crude oil, or naphthenic-based crude oil to atmospheric distillation; distillate oil obtained by subjecting these atmospheric residues to vacuum distillation; and mineral oil obtained by subjecting the distillate oil to one or more refining treatments of solvent deasphalting, solvent extraction, hydrocracking, solvent dewaxing, catalytic dewaxing, and hydrorefining.

16. The lubricating oil composition according to claim 14, wherein, The synthetic oil is one or more selected from α-olefin homopolymer, α-olefin copolymer, isomeric paraffin; polyol ester, dibasic acid ester, polyphenyl ether, polyalkylene glycol, alkylbenzene, alkylnaphthalene, and GTL base oil obtained by isomerization of wax, that is, GTL wax, manufactured from natural gas using the Fischer-Tropsch method.

17. The lubricating oil composition according to claim 14, wherein, The base oil A contains mineral oil, and the content of the mineral oil is 50 mass% to 100 mass% based on the total amount of the base oil A.

18. The lubricating oil composition according to any one of claims 1 to 3, wherein, 19. The lubricating oil composition according to any one of claims 1 to 3, wherein, The base oil A has a kinematic viscosity at 100°C of 1 mm 2 / s ~ 25 mm 2 / s. The viscosity index of the base oil A is 100 or more.

20. The lubricating oil composition according to any one of claims 1 to 3, wherein, The content of the base oil A is 65 mass% to 95 mass% based on the total amount of the lubricating oil composition.

21. The lubricating oil composition according to any one of claims 1 to 3, wherein, The zinc dithiophosphate B is a compound represented by the following general formula (b-1), 22. The lubricating oil composition according to any one of claims 1 to 3, wherein, In the general formula (b-1), R b1 ~R b4 each independently represents a hydrocarbon group. The content of the zinc dithiophosphate B is 0.50 mass% or more and 2.00 mass% or less based on the total amount of the lubricating oil composition. ​ 23. The lubricating oil composition of any of claims 1-3, wherein, The sarcosine-based compound C is a sarcosine-based compound C1 represented by the following general formula (c-1), In the general formula (c-1), R c1 represents a hydrocarbon group having 2 to 30 carbon atoms which optionally contains a hetero atom, R c2 represents a hydrogen atom or a methyl group.

24. The lubricating oil composition of claim 23, wherein, The sarcosine-based compound C1 is a sarcosine-based compound C2 represented by the following general formula (c-2), In General Formula (c-2), R C3 represents a hydrocarbon group having 1 to 29 carbons.

25. The lubricating oil composition according to claim 24, wherein The sarcosine compound C2 represented by the general formula (c-2) is a compound in which R c3 is an alkenyl group having 17 carbon atoms, i.e., N-oleoylsarcosine.

26. The lubricating oil composition according to any one of claims 1 to 3, wherein The phosphorus-based compound D does not include zinc dithiophosphate B.

27. The lubricating oil composition according to any one of claims 1 to 3, wherein The acidic phosphate D1 is a compound represented by the following general formula (d-1), In the general formula (d-1), R d1 each independently represents a hydrocarbon group having a carbon number of 1 to 30.

28. The lubricating oil composition according to claim 27, wherein The acidic phosphate represented by the general formula (d-1) is one or more selected from the group consisting of mono- or diethyl acid phosphate, mono- or di-n-propyl acid phosphate, mono- or di-2-ethylhexyl acid phosphate, mono- or dibutyl acid phosphate, mono- or dioctyl acid phosphate, mono- or didocosyl acid phosphate, mono- or dioleyl acid phosphate, mono- or diisodecyl acid phosphate, mono- or dilauryl acid phosphate, mono- or distearyl acid phosphate, and mono- or diisostearyl acid phosphate.

29. The lubricating oil composition according to any one of claims 1 to 3, wherein The amine salt D2 is an amine salt formed from the acidic phosphate D1 and an amine, and the amine used in the formation of the amine salt is an amine represented by the following general formula (d-2), In General Formula (d-2), R d2 represents a hydrocarbon group having 1 to 30 carbons, and n is 1, 2, or 3.

30. The lubricating oil composition according to any one of claims 1 to 3, wherein In the case where the condition (a) is satisfied, the content of the phosphorus-based compound D is 0.05 mass% or more and 1.25 mass% or less based on the total amount of the lubricating oil composition.

31. The lubricating oil composition according to any one of claims 1 to 3, wherein In the case where the condition (a) is satisfied, the content ratio D / C of the phosphorus-based compound D to the sarcosine-based compound C exceeds 0.50 and is 12.5 or less in terms of mass ratio.

32. The lubricating oil composition according to any one of claims 1 to 3, wherein In the case where the condition (b) is satisfied, the content ratio D / C of the phosphorus-based compound D to the sarcosine-based compound C is 0.40 or more and less than 1.67 in terms of mass ratio.

33. The lubricating oil composition according to any one of claims 1 to 3, wherein As the other additives, one or more selected from the group consisting of an antioxidant, a friction modifier, an oiliness agent, a metal deactivator, a detergent, a dispersant, a viscosity index improver, a pour point depressant, an antifoaming agent, a rust preventive, and an extreme pressure agent is contained.

34. The lubricating oil composition according to claim 33, wherein The total content of the other additives is 0 mass% or more and 25 mass% or less based on the total amount of the lubricating oil composition.

35. The lubricating oil composition according to claim 33, wherein The viscosity index improver is a non-dispersed polymethacrylate PMA having a mass average molecular weight Mw in the range of 10,000 to 300,000 and two or more kinds of non-dispersed polymethacrylates PMA having different mass average molecular weights Mw are used in combination.

36. The lubricating oil composition according to any one of claims 1 to 3, The lubricating oil composition has a kinematic viscosity at 40°C of 10 mm 2 / s or more and 70 mm 2 / s or less.

37. The lubricating oil composition according to any one of claims 1 to 3, The lubricating oil composition has a kinematic viscosity at 100°C of 5.0 mm 2 / s or more and 11 mm 2 / s or less.

38. The lubricating oil composition according to any one of claims 1 to 3, The viscosity index of the lubricating oil composition is 180 or more.

39. The lubricating oil composition according to any one of claims 1 to 3, The base number of the lubricating oil composition is 4 mgKOH / g or more and 12 mgKOH / g or less.

40. The lubricating oil composition according to any one of claims 1 to 3, wherein The calcium atom content is 2500 mass ppm or more and 5000 mass ppm or less based on the total amount of the lubricating oil composition.

41. The lubricating oil composition according to any one of claims 1 to 3, wherein The phosphorus atom content is 500 mass ppm or more and 2000 mass ppm or less based on the total amount of the lubricating oil composition.

42. The lubricating oil composition according to any one of claims 1 to 3, wherein The zinc atom content is 500 mass ppm or more and 2000 mass ppm or less based on the total amount of the lubricating oil composition.

43. The lubricating oil composition according to any one of claims 1 to 3, wherein The sulfur atom content is 0.10 mass% or more and 0.30 mass% or less based on the total amount of the lubricating oil composition.

44. The lubricating oil composition according to any one of claims 1 to 3, wherein The nitrogen atom content is 250 mass ppm or more and 1200 mass ppm or less based on the total amount of the lubricating oil composition.

45. The lubricating oil composition of any of claims 1-3, based on the coefficient of friction, μ, at 80°C as determined using a low velocity sliding friction apparatus (LVFA) tester according to JASO M 349:2012. 50 less than 0.

115.

46. The lubricating oil composition according to any one of claims 1 to 3, which has a load-carrying capacity, i.e., a seizure resistance, of more than 0.50 MPa as measured in accordance with JIS K2519: 1995 using a Sueda four-ball tester at a rotational speed of 200 rpm.

47. The lubricating oil composition according to any one of claims 1 to 3, which is used for lubrication of an industrial machine.

48. The lubricating oil composition of claim 47, wherein, The industrial machine has a transmission, a hydraulic working section, and a wet brake.

49. The lubricating oil composition of claim 47, wherein, The industrial machine is an agricultural machine.

50. A method for lubricating an industrial machine, which uses the lubricating oil composition according to any one of claims 1 to 46.

51. The lubricating method of claim 50, wherein, The industrial machine has a transmission, a hydraulic working section, and a wet brake.

52. The lubricating method of claim 50 or 51, wherein, The industrial machine is an agricultural machine.

53. A method for producing a lubricating oil composition, which is a method for producing the lubricating oil composition according to any one of claims 1 to 46, having a step SI of compounding a base oil A, a zinc dithiophosphate B, and a sarcosine-based compound C.

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